Polyfunctional vinyl aromatic copolymer, process for producing the same, copolymer rubber obtained therefrom, rubber composition, rubber crosslinked product, and tire member

文档序号：620868 发布日期：2021-05-07 浏览：39次中文

阅读说明：本技术 多官能乙烯基芳香族共聚物及其制造方法、由其获得的共聚物橡胶、橡胶组合物、橡胶交联物和轮胎构件 (Polyfunctional vinyl aromatic copolymer, process for producing the same, copolymer rubber obtained therefrom, rubber composition, rubber crosslinked product, and tire member ) 是由川辺正直仓富格岩下新一于 2019-09-26 设计创作，主要内容包括：提供一种具有可用于共聚物橡胶的制造的反应性与可溶性的多官能乙烯基芳香族共聚物、以及由其获得的兼备加工性、强度及均质性的共聚物橡胶材料。一种多官能乙烯基芳香族共聚物,含有0.5摩尔％以上且40摩尔％以下的源自二乙烯基芳香族化合物的结构单元(a),且含有60摩尔％以上且99.5摩尔％以下的源自单乙烯基芳香族化合物的结构单元(b),所述多官能乙烯基芳香族共聚物的特征在于：结构单元(a)的至少一部分为由下述式(2)所表示的交联结构单元(a2)、以及由下述式(1)所表示的含乙烯基的结构单元(a1),(式中,R～1独立地表示碳数6～30的芳香族烃基。)交联结构单元(a2)相对于结构单元(a)的摩尔分率为0.05～0.50的范围,含乙烯基的结构单元(a1)相对于结构单元(a)及结构单元(b)的总和的摩尔分率为0.001～0.35的范围,多官能乙烯基芳香族共聚物的数量平均分子量Mn为1,000～50,000,由重量平均分子量Mw与数量平均分子量Mn之比所表示的分子量分布(Mw/Mn)为8.0以下。(Provided are a reactive and soluble polyfunctional vinyl aromatic copolymer which can be used for producing a copolymer rubber, and a copolymer rubber material obtained therefrom which has processability, strength and homogeneity. A polyfunctional vinyl aromatic copolymer containing 0.5 to 40 mol% of a structural unit (a) derived from a divinyl aromatic compound and containing 60 to 99.5 mol% of a structural unit (b) derived from a monovinyl aromatic compound, characterized in that: at least a part of the structural unit (a) is a crosslinking structural unit (a2) represented by the following formula (2) and a vinyl-containing structural unit (a1) represented by the following formula (1), (wherein R is 1 Independently represent an aromatic hydrocarbon group having 6 to 30 carbon atoms. ) The molar fraction of the crosslinking structural unit (a2) relative to the structural unit (a) is in the range of 0.05 to 0.50, the molar fraction of the vinyl-containing structural unit (a1) relative to the sum of the structural unit (a) and the structural unit (b) is in the range of 0.001 to 0.35, the number average molecular weight Mn of the polyfunctional vinyl aromatic copolymer is in the range of 1,000 to 50,000, and the molecular weight distribution (Mw/Mn), represented by the ratio of the weight average molecular weight Mw to the number average molecular weight Mn, is 8.0 or less.)

1. A multifunctional vinyl aromatic copolymer comprising: 5 to 35 mol% of a structural unit (a) derived from a divinylaromatic compound; 5 to 25 mol% of a structural unit (b) derived from a monovinyl aromatic compound; and 40 to 90 mol% of a structural unit (c) derived from a cycloolefin monomer having an aromatic fused ring structure, wherein at least a part of the structural unit (a) is a vinyl group-containing structural unit (a1) represented by the following formula (1),

[ solution 1]

(wherein R1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms.)

The molar fraction of the vinyl group-containing structural unit (a1) to the total of the structural unit (a), the structural unit (b) and the structural unit (c) is in the range of 0.01 to 0.30.

2. The polyfunctional vinyl aromatic copolymer according to claim 1, wherein the number average molecular weight Mn is 300 to 100,000, the molecular weight distribution (Mw/Mn) represented by the ratio of the weight average molecular weight Mw to the number average molecular weight Mn is 10.0 or less, and the copolymer is soluble in toluene, xylene, tetrahydrofuran, dichloroethane or chloroform.

3. The polyfunctional vinyl aromatic copolymer according to claim 1, wherein the cycloolefin-based monomer is at least one monomer selected from the group consisting of indene-based compounds, acenaphthene-based compounds, benzofuran-based compounds and benzothiophene-based compounds.

4. A method for producing a polyfunctional vinyl aromatic copolymer, characterized in that: the polyfunctional vinyl aromatic copolymer according to claim 1, wherein the polymerization is carried out in the presence of a Lewis acid catalyst in a homogeneous solvent obtained by dissolving a polymerization raw material comprising a divinyl aromatic compound, a monovinyl aromatic compound and a cycloolefin monomer having an aromatic condensed ring structure in a solvent having a dielectric constant of 2.0 to 15.0 at a temperature of 20 to 120 ℃.

5. A conjugated diene copolymer characterized in that: the polyfunctional vinyl aromatic copolymer (A) according to claim 1, which is obtained by copolymerizing a conjugated diene compound (B) with the polyfunctional vinyl aromatic copolymer (A) or by copolymerizing the polyfunctional vinyl aromatic copolymer (A) with the conjugated diene compound (B) and an aromatic vinyl compound (C).

6. The conjugated diene copolymer according to claim 5, wherein: contains 0.001 to 6% by weight of a structural unit (A1) derived from a polyfunctional vinyl aromatic copolymer, 29 to 99.999% by weight of a structural unit (B1) derived from a conjugated diene compound, and 0 to 70% by weight of a structural unit (C1) derived from an aromatic vinyl compound.

7. The conjugated diene copolymer according to claim 5, wherein the polymerization active end of the conjugated diene copolymer is further reacted with a modifier.

8. A conjugated diene copolymer composition characterized in that: the conjugated diene copolymer according to claim 5, wherein the reinforcing filler is at least one selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides and carbon black in an amount of 0.5 to 200 parts by weight based on 100 parts by weight of the conjugated diene copolymer.

9. The conjugated diene copolymer composition according to claim 8, further comprising a crosslinking agent.

10. A crosslinked rubber product characterized by: the conjugated diene copolymer composition according to claim 9, which is crosslinked.

11. A tire member comprising the conjugated diene copolymer composition according to claim 8.

12. A multifunctional vinyl aromatic copolymer comprising: 0.5 to 40 mol% of a structural unit (a) derived from a divinylaromatic compound; and 60 to 99.5 mol% of a structural unit (b) derived from a monovinyl aromatic compound, wherein at least a part of the structural unit (a) is a crosslinking structural unit (a2) represented by the following formula (2) and a vinyl group-containing structural unit (a1) represented by the following formula (1),

[ solution 2]

(in the formula, R¹Independently represent an aromatic hydrocarbon group having 6 to 30 carbon atoms. )

The molar fraction of the crosslinking structural unit (a2) relative to the structural unit (a) is in the range of 0.05 to 0.50, the molar fraction of the vinyl-containing structural unit (a1) relative to the sum of the structural unit (a) and the structural unit (b) is in the range of 0.001 to 0.35, the number average molecular weight Mn of the polyfunctional vinyl aromatic copolymer is in the range of 1,000 to 50,000, and the molecular weight distribution (Mw/Mn), represented by the ratio of the weight average molecular weight Mw to the number average molecular weight Mn, is 8.0 or less.

13. The polyfunctional vinyl aromatic copolymer according to claim 12, wherein a haze value of a solution obtained by dissolving 0.5g of the polyfunctional vinyl aromatic copolymer in 100g of toluene is 0.1 or less.

14. The multifunctional vinyl aromatic copolymer according to claim 12, wherein the monovinyl aromatic compound is one or more monomers selected from the group consisting of styrene, vinyl naphthalene, vinyl biphenyl, m-methylstyrene, p-methylstyrene, o, p-dimethylstyrene, m-ethylvinylbenzene, and p-ethylvinylbenzene.

15. A method for producing a polyfunctional vinyl aromatic copolymer, characterized in that: the polyfunctional vinyl aromatic copolymer according to claim 12, wherein the polymerization is carried out in the presence of a Lewis acid catalyst in a homogeneous solvent obtained by dissolving a polymerization raw material comprising a divinyl aromatic compound and a monovinyl aromatic compound in a solvent having a dielectric constant of 2.0 to 15.0 at a temperature of 20 to 60 ℃.

16. A conjugated diene copolymer characterized in that: the polyfunctional vinyl aromatic copolymer (A) according to claim 1, which is obtained by copolymerizing a conjugated diene compound (B) with the polyfunctional vinyl aromatic copolymer (A) or by copolymerizing the polyfunctional vinyl aromatic copolymer (A) with the conjugated diene compound (B) and an aromatic vinyl compound (C).

17. The conjugated diene copolymer according to claim 16, comprising 0.001 to 6% by weight of the structural unit (A1) derived from a polyfunctional vinyl aromatic copolymer, 29 to 99.999% by weight of the structural unit (B1) derived from a conjugated diene compound, and 0 to 70% by weight of the structural unit (C1) derived from an aromatic vinyl compound.

18. The conjugated diene copolymer according to claim 16, wherein a polymerization active end of the conjugated diene copolymer is further modified by reacting with a modifier.

19. A conjugated diene copolymer composition characterized in that: the conjugated diene copolymer according to claim 16, wherein the reinforcing filler is at least one selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides and carbon black in an amount of 0.5 to 200 parts by weight based on 100 parts by weight of the conjugated diene copolymer.

20. The conjugated diene copolymer composition according to claim 19, further comprising a crosslinking agent.

21. A crosslinked rubber product characterized by: the conjugated diene copolymer composition according to claim 20, which is crosslinked.

22. A tire member comprising the rubber vulcanizate of claim 21.

23. A multifunctional vinyl aromatic copolymer comprising: 0.5 mol% or more and 75 mol% or less of a structural unit (a) derived from a divinylaromatic compound; 5.0 mol% or more and 75 mol% or less of a structural unit (b) derived from a monovinyl aromatic compound having no substituent at the α -position; and 5.0 mol% or more and 75 mol% or less of a structural unit (c) derived from an alpha, alpha-disubstituted olefin compound, wherein at least a part of the structural unit (a) is a crosslinking structural unit (a2) represented by the following formula (2) and a vinyl group-containing structural unit (a1) represented by the following formula (1),

[ solution 3]

(in the formula, R¹Independently represent an aromatic hydrocarbon group having 6 to 30 carbon atoms. )

The molar fraction of the crosslinking structural unit (a2) relative to the structural unit (a) is in the range of 0.05 to 0.60, the molar fraction of the vinyl-containing structural unit (a1) relative to the total of the structural unit (a), the structural unit (b), and the structural unit (c) is in the range of 0.001 to 60,

the polyfunctional vinyl aromatic copolymer has a number average molecular weight Mn of 300 to 50,000 and a molecular weight distribution (Mw/Mn) represented by the ratio of the weight average molecular weight Mw to the number average molecular weight Mn of 10.0 or less.

24. The multifunctional vinyl aromatic copolymer of claim 23 wherein the α, α -disubstituted olefin compound is selected from the group consisting of isobutylene, diisobutylene, 2-methyl-1-butene, 2-methyl-1-pentene, 1-methyl-1-cyclopentene, 2-methyl-1-hexene, 1-methyl-1-cyclohexene, 2-methyl-1-heptene, 2-methyl-1-octene, 2-methyl-1-nonene, 2-methyl-1-decene, 2-methyl-1-dodecene, 2-methyl-1-tetradecene, 2-methyl-1-hexadecene, 2-methyl-1-octadecene, 2-methyl-1-decene, 1-methyl-1-decene, 2-methyl-1-dece, 2-methyl-1-eicosene, 2-methyl-1-eicosadiene, 2-methyl-1-tetracosene, alpha-methylstyrene.

25. The multifunctional vinyl aromatic copolymer according to claim 23, wherein the monovinyl aromatic compound having no substituent at the α -position is one or more monomers selected from the group consisting of styrene, vinyl naphthalene, vinyl biphenyl, m-methylstyrene, p-methylstyrene, o, p-dimethylstyrene, m-ethylvinylbenzene, and p-ethylvinylbenzene.

26. A method for producing a polyfunctional vinyl aromatic copolymer, characterized in that: the polyfunctional vinyl aromatic copolymer according to claim 23, wherein the polymerization raw material comprising a divinyl aromatic compound, a monovinyl aromatic compound having no substituent at the α -position, and an α, α -disubstituted olefin compound is dissolved in a solvent having a dielectric constant of 2.0 to 15.0 in a homogeneous solvent, and the polymerization is carried out at a temperature of 0 to 120 ℃ in the presence of a Lewis acid catalyst.

27. A conjugated diene copolymer characterized in that: obtained by copolymerizing the polyfunctional vinyl aromatic copolymer (A) according to claim 23 with the conjugated diene compound (B) or with the conjugated diene compound (B) and the aromatic vinyl compound (C).

28. The conjugated diene copolymer according to claim 27, comprising 0.001 to 6% by weight of the structural unit (A1) derived from a polyfunctional vinyl aromatic copolymer, 29 to 99.999% by weight of the structural unit (B1) derived from a conjugated diene compound, and 0 to 70% by weight of the structural unit (C1) derived from an aromatic vinyl compound.

29. The conjugated diene copolymer according to claim 27, wherein a polymerization active end of the conjugated diene copolymer is further modified by reacting with a modifier.

30. A conjugated diene copolymer composition characterized in that: the conjugated diene copolymer according to claim 27, wherein the reinforcing filler is at least one selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides and carbon black in an amount of 0.5 to 200 parts by weight based on 100 parts by weight of the conjugated diene copolymer.

31. The conjugated diene copolymer composition according to claim 30, further comprising a crosslinking agent.

32. A crosslinked rubber product characterized by: the conjugated diene copolymer composition according to claim 31, which is crosslinked.

33. A tire member comprising the rubber vulcanizate of claim 32.

Technical Field

The present invention particularly relates to a polyfunctional vinyl aromatic copolymer excellent in copolymerization reactivity with a conjugated diene compound (B) and an aromatic vinyl compound (C) in the presence of an anionic polymerization initiator, a method for producing the same, a conjugated diene copolymer excellent in processability and excellent in tensile strength and abrasion resistance, a conjugated diene copolymer composition containing the conjugated diene copolymer, and a crosslinked rubber product and a tire member obtained by crosslinking the conjugated diene copolymer composition.

Background

Conjugated diene rubbers such as styrene-butadiene rubber (SBR), Butadiene Rubber (BR), and Isoprene Rubber (IR), styrene-isoprene rubber, have excellent abrasion resistance, elasticity, and water resistance, and are used in various applications such as molding materials and modifiers for resins.

One of the main uses of the conjugated diene rubber is a tire for automobiles. The properties required for the tire include mechanical strength, abrasion resistance, wet skid resistance (wet grip) and the like (hereinafter also referred to collectively as strength and the like). Further, in recent years, development of a tire (so-called "eco tire") excellent in energy saving performance, i.e., low fuel consumption has been actively conducted. The ecological tire is required to have not only strength and the like but also low rolling resistance.

It is known to add a filler (reinforcing filler) such as carbon black or silica to a conjugated diene rubber in order to secure the strength of a tire, etc., but a solution-polymerization-type SBR having a modified end (S-SBR-modified end) attracts attention as a material for further improving the strength of a tire, etc. and imparting excellent rolling resistance. The terminal-modified S-SBR has a functional group at the molecular terminal of the SBR, which interacts with the filler. By the interaction, the dispersibility of the filler in the SBR is improved, and the molecular terminals of the SBR are restrained, and the mobility is reduced. As a result, hysteresis loss (internal friction) of the tire is reduced, and rolling resistance is reduced. By effectively utilizing the above characteristics, an ecological tire having both strength and the like and low rolling resistance has been developed.

For example, in patent document 1, a block copolymer including an α -methylstyrene block and a butadiene block is synthesized by living anionic polymerization (living anionic polymerization) using an organolithium compound as an initiator in a nonpolar solvent, and a polyfunctional coupling agent is reacted as necessary, thereby obtaining S-SBR having both high temperature characteristics and rubber properties.

Patent document 2 discloses a star-block interpolymer (star-block interpolymer) having a random copolymer block of a conjugated diene and a monovinyl aromatic monomer, a poly-conjugated diene block, and a functional group derived from a polyfunctional lithium initiator, and has been widely used as a rubber for producing a tire tread having excellent characteristics such as reduction of rolling resistance and improvement of traction (traction) characteristics.

Patent documents 1 and 2 suggest that the rubber processability can be ensured by introducing a branched structure into the rubber component. However, the interaction with the filler for ensuring the strength is not designed in particular, and the contribution to the strength is insufficient.

Patent document 3 discloses a rubber composition in which a predetermined amount of carbon black is blended into a mixed rubber containing a plurality of diene rubbers, wherein a polymer containing a functional group having a low molecular weight and a functional group having a functional group interacting with carbon black is blended at a molecular chain end and having a polymer structure similar to that of a rubber component of the diene rubber. The rubber composition can control the distribution amount of carbon black to each diene rubber component by blending a low-molecular compound having an interaction with carbon black in a rubber. Therefore, the characteristics of the respective rubber components can be effectively expressed, and the balance of rubber characteristics such as rolling characteristics and wet (wet) characteristics which are in an inverse relationship can be achieved. However, the technique is not sufficient in terms of contribution to strength because it compounds a low molecular weight to the rubber.

Patent document 4 discloses crosslinked rubber particles containing a conjugated diene monomer unit, an aromatic vinyl monomer unit, and a monomer unit having at least two polymerizable unsaturated groups, and a rubber composition containing a conjugated diene/aromatic vinyl copolymer rubber containing a conjugated diene monomer unit having a specific bond structure, and discloses that the crosslinked rubber particles may contain a monomer unit having a carboxylic acid group, a hydroxyl group, and/or an epoxy group. The above technique has a moderate interaction with an inorganic filler (filler) such as silica, and therefore, the inorganic filler is excellent in dispersibility and processability. However, the monomer units having at least two polymerizable unsaturated groups or the monomer units having a carboxylic acid group, a hydroxyl group and/or an epoxy group are all low-molecular monomers. Therefore, the reactivity is too high, and the crosslinked rubber particles and the rubber composition may be gelled. In addition, the technology requires that a crosslinked rubber is synthesized separately from a conjugated diene/aromatic vinyl copolymer rubber and then the crosslinked rubber is blended with the conjugated diene/aromatic vinyl copolymer rubber, and improvement is required from the viewpoint of ease of the process.

In view of the above-mentioned problems, the present applicant has found that a copolymer rubber having processability, strength and homogeneity in combination can be provided by using a specific polyfunctional vinyl aromatic copolymer compound having both a branching structure and a function of interacting with a filler as a constituent unit of a conjugated diene rubber (patent document 5).

However, the above polyfunctional vinyl aromatic copolymer compound has a problem that a small amount of microgel (microgel) is additionally produced although gelation is greatly improved.

The present applicant has disclosed a compound similar to the polyfunctional vinyl aromatic copolymer compound disclosed in patent document 5 in patent document 6, patent document 7, and the like. However, these similar compounds are not taught to be used as constituent units of the copolymer rubber.

Further, the polyfunctional vinyl aromatic copolymer disclosed in patent document 8 has a broad molecular weight distribution and contains a large amount of a high molecular weight material having a significantly developed branch structure, and therefore, when used as a constituent unit of a copolymer rubber, there is a problem that a small amount of microgel is generated.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2003-73434

Patent document 2: japanese patent laid-open publication No. 2004-517202

Patent document 3: japanese patent laid-open No. 2005-213381

Patent document 4: international publication No. 2002/000779

Patent document 5: international publication No. 2018/084128

Patent document 6: japanese patent laid-open No. 2004-123873

Patent document 7: japanese patent laid-open publication No. 2018-39995

Patent document 8: international publication No. 2018/181842

Disclosure of Invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide a polyfunctional vinyl aromatic copolymer which is useful for producing a copolymer rubber, has reactivity and solubility, and does not cause generation of a small amount of microgel, and a copolymer rubber material having processability, strength and homogeneity.

As a result of extensive studies, the present inventors have found that a polyfunctional vinyl aromatic copolymer as a first invention, which contains a structural unit (a) derived from a divinyl aromatic compound, a structural unit (b) derived from a monovinyl aromatic compound, and a structural unit (c) derived from a cycloolefin monomer having an aromatic fused ring structure, has high reactivity in the production of a copolymer rubber, and have found that the above-mentioned problems are solved by using the polyfunctional vinyl aromatic copolymer as a structural unit of a conjugated diene rubber, and have completed the present invention.

The first invention is a polyfunctional vinyl aromatic copolymer containing: 5 to 35 mol% of a structural unit (a) derived from a divinylaromatic compound; 5 to 25 mol% of a structural unit (b) derived from a monovinyl aromatic compound; and 40 to 90 mol% of a structural unit (c) derived from a cycloolefin monomer having an aromatic fused ring structure, wherein at least a part of the structural unit (a) is a vinyl group-containing structural unit (a1) represented by the following formula (1),

[ solution 1]

(wherein R1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms.)

The molar fraction of the vinyl group-containing structural unit (a1) to the total of the structural unit (a), the structural unit (b) and the structural unit (c) is in the range of 0.01 to 0.30.

The polyfunctional vinyl aromatic copolymer has a number average molecular weight Mn of 300 to 100,000, a molecular weight distribution (Mw/Mn) represented by the ratio of the weight average molecular weight Mw to the number average molecular weight Mn of 10.0 or less, and is soluble in toluene, xylene, tetrahydrofuran, dichloroethane or chloroform.

The cycloolefin-based monomer includes at least one monomer selected from the group consisting of an indene-based compound, an acenaphthene-based compound, a benzofuran-based compound, and a benzothiophene-based compound.

The present invention also provides a method for producing the above polyfunctional vinyl aromatic copolymer, comprising: polymerization is carried out in the presence of a Lewis acid catalyst at a temperature of 20 to 120 ℃ in a homogeneous solvent in which a polymerization raw material comprising a divinylaromatic compound, a monovinylaromatic compound and a cycloolefin monomer having an aromatic condensed ring structure is dissolved in a solvent having a dielectric constant of 2.0 to 15.0.

The present invention also provides a conjugated diene copolymer characterized in that: the polyfunctional vinyl aromatic copolymer (A) is copolymerized with a conjugated diene compound (B) or with a conjugated diene compound (B) and an aromatic vinyl compound (C).

The conjugated diene copolymer may contain 0.001 to 6 wt% of a structural unit (a1) derived from a polyfunctional vinyl aromatic copolymer, 29 to 99.999 wt% of a structural unit (B1) derived from a conjugated diene compound, and 0 to 70 wt% of a structural unit (C1) derived from an aromatic vinyl compound. The polymerization active terminal of the conjugated diene copolymer may be further reacted with a modifier.

The present invention also provides a conjugated diene copolymer composition, comprising: the reinforcing filler is at least one selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides and carbon black, and is contained in an amount of 0.5 to 200 parts by weight based on 100 parts by weight of the conjugated diene-based copolymer.

The conjugated diene copolymer composition may further contain a crosslinking agent.

The present invention also provides a crosslinked rubber product, characterized in that: and a crosslinking agent is added to the conjugated diene copolymer composition.

The present invention also provides a tire member comprising the conjugated diene copolymer composition.

As a result of extensive studies, the present inventors have found that a polyfunctional vinyl aromatic copolymer of the second invention, which contains a structural unit (a) derived from a divinyl aromatic compound and a structural unit (b) derived from a monovinyl aromatic compound and has a specific degree of crosslinking, a mole fraction of a vinyl-containing structural unit, and solubility, has high reactivity in the production of a copolymer rubber, and have found that the above-mentioned problems are solved by using the polyfunctional vinyl aromatic copolymer as a structural unit of a conjugated diene rubber, thereby completing the present invention.

The second invention is a polyfunctional vinyl aromatic copolymer containing: 0.5 to 40 mol% of a structural unit (a) derived from a divinylaromatic compound; and 60 to 99.5 mol% of a structural unit (b) derived from a monovinyl aromatic compound, wherein at least a part of the structural unit (a) is a crosslinking structural unit (a2) represented by the following formula (2) and a vinyl group-containing structural unit (a1) represented by the following formula (1),

[ solution 2]

(in the formula, R¹Independently represent an aromatic hydrocarbon group having 6 to 30 carbon atoms. )

A sample prepared by dissolving 0.5g of the polyfunctional vinyl aromatic copolymer in 100g of toluene was placed in a quartz cell, and the Haze value of the sample measured by an integrating sphere type light transmittance measuring instrument with respect to toluene was 0.1 or less.

The monovinyl aromatic compound may be at least one monomer selected from the group consisting of styrene, vinylnaphthalene, vinylbiphenyl, m-methylstyrene, p-methylstyrene, o, p-dimethylstyrene, m-ethylvinylbenzene, and p-ethylvinylbenzene.

The present invention also provides a method for producing the above polyfunctional vinyl aromatic copolymer, comprising: polymerization is carried out in the presence of a Lewis acid catalyst in a homogeneous solvent in which a polymerization raw material comprising a divinyl aromatic compound and a monovinyl aromatic compound is dissolved in a solvent having a dielectric constant of 2.0 to 15.0 at a temperature of 20 to 120 ℃.

The conjugated diene copolymer composition may further contain a crosslinking agent.

The present invention also provides a crosslinked rubber product, characterized in that: and a crosslinking agent is added to the conjugated diene copolymer composition.

The present invention also provides a tire member comprising the conjugated diene copolymer composition.

As a result of extensive studies, the present inventors have found that a polyfunctional vinyl aromatic copolymer divinyl aromatic compound as a third invention containing a structural unit (a) derived from a divinyl aromatic compound, a structural unit (b) derived from a monovinyl aromatic compound having no substituent at the α -position, and a structural unit (c) derived from an α, α -disubstituted olefin compound has high reactivity at the time of production of a copolymer rubber, and have found that the above-mentioned problem is solved by using the polyfunctional vinyl aromatic copolymer as a constituent unit of a conjugated diene rubber, thereby completing the present invention.

The third invention is a polyfunctional vinyl aromatic copolymer containing: 0.5 mol% or more and 75 mol% or less of a structural unit (a) derived from a divinylaromatic compound; 5.0 mol% or more and 75 mol% or less of a structural unit (b) derived from a monovinyl aromatic compound having no substituent at the α -position; and 5.0 mol% or more and 75 mol% or less of a structural unit (c) derived from an alpha, alpha-disubstituted olefin compound, wherein at least a part of the structural unit (a) is a crosslinking structural unit (a2) represented by the following formula (2) and a vinyl group-containing structural unit (a1) represented by the following formula (1),

[ solution 3]

(in the formula, R¹Independently represent an aromatic hydrocarbon group having 6 to 30 carbon atoms. )

The α, α -disubstituted olefin compound may be exemplified by compounds selected from the group consisting of isobutylene, diisobutylene, 2-methyl-1-butene, 2-methyl-1-pentene, 1-methyl-1-cyclopentene, 2-methyl-1-hexene, 1-methyl-1-cyclohexene, 2-methyl-1-heptene, 2-methyl-1-octene, 2-methyl-1-nonene, 2-methyl-1-decene, 2-methyl-1-dodecene, 2-methyl-1-tetradecene, 2-methyl-1-hexadecene, 2-methyl-1-octadecene, 2-methyl-1-eicosene, 2-methyl-1-decene, 2-methyl-1-eicosadiene, 2-methyl-1-tetracosene, alpha-methylstyrene.

The monovinyl aromatic compound having no substituent at the α -position includes at least one monomer selected from the group consisting of styrene, vinylnaphthalene, vinylbiphenyl, m-methylstyrene, p-methylstyrene, o, p-dimethylstyrene, m-ethylvinylbenzene, and p-ethylvinylbenzene.

The present invention also provides a method for producing the above polyfunctional vinyl aromatic copolymer, comprising: polymerization is carried out in the presence of a Lewis acid catalyst in a homogeneous solvent in which a polymerization raw material comprising a divinylaromatic compound, a monovinylaromatic compound having no substituent at the alpha-position, and an alpha, alpha-disubstituted olefin compound is dissolved in a solvent having a dielectric constant of 2.0 to 15.0, at a temperature of 0 to 120 ℃.

The reinforcing filler may be at least one selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides, and carbon black in an amount of 0.5 to 200 parts by weight based on 100 parts by weight of the conjugated diene-based copolymer.

The conjugated diene copolymer composition may further contain a crosslinking agent.

The present invention also provides a crosslinked rubber product, characterized in that: and a crosslinking agent is added to the conjugated diene copolymer composition.

The present invention also provides a tire member comprising the conjugated diene copolymer composition.

The polyfunctional vinyl aromatic copolymer of the present invention has reactivity and solubility useful for the production of copolymer rubbers, and is therefore suitable as a raw material thereof. The conjugated diene copolymer of the present invention has a structural unit having both a branching structure and a function of interacting with a filler, and therefore is excellent as a rubber having both processability and strength. Further, the gel-like material is not easily formed and is homogeneous, and therefore, the gel-like material is suitable for molding materials, modifiers for resins, and the like.

Furthermore, a crosslinked rubber composition obtained by crosslinking a conjugated diene copolymer containing a filler is excellent in mechanical strength and abrasion resistance because of excellent dispersibility of the filler.

Detailed Description

The polyfunctional vinyl aromatic copolymer of the first invention will be explained.

The polyfunctional vinyl aromatic copolymer of the present invention contains a structural unit (a) derived from a divinyl aromatic compound, a structural unit (b) derived from a monovinyl aromatic compound, and a structural unit (c) derived from a cycloolefin monomer having an aromatic condensed ring structure.

The number average molecular weight Mn may be 300 to 100,000, the molecular weight distribution (Mw/Mn) represented by the ratio of the weight average molecular weight Mw to the number average molecular weight Mn may be 10.0 or less, and the polymer may be soluble in toluene, xylene, tetrahydrofuran, dichloroethane or chloroform.

The polyfunctional vinyl aromatic copolymer of the present invention is preferably solvent-soluble and is therefore also referred to as a soluble polyfunctional vinyl aromatic copolymer, or simply as a copolymer.

The structural unit described in the present specification means a repeating unit present in the main chain of the copolymer.

The structural unit (a) derived from a divinylaromatic compound may have a plurality of structurally different structural units such as a structural unit in which only one vinyl group is reacted and a structural unit in which two vinyl groups are reacted, and the structural unit (a1) may include a structural unit in which only one vinyl group is reacted in a molar fraction of 0.01 to 0.30, that is, a structural unit containing a vinyl group represented by the formula (1).

The preferred lower limit is 0.04, more preferably 0.05. The upper limit is preferably 0.25, more preferably 0.20. By setting the above range, a copolymer rubber can be obtained which has excellent reactivity when copolymerized with a conjugated diene compound while maintaining solubility, has excellent compatibility with a diene rubber, and has excellent processability, tensile strength, and abrasion resistance. When the molar fraction is less than 0.01, the copolymerization reactivity with a conjugated diene compound or the like tends to be lowered, and when it exceeds 0.30, a microgel tends to be formed at the time of copolymerization.

Here, the mole fraction is a mole fraction of the vinyl group-containing structural unit (a1) with respect to the total of the structural unit (a), the structural unit (b), and the structural unit (c), and is calculated by the following formula (12).

(a1)/[(a)+(b)+(c)]…(12)

Here, (a), (b), (c) and (a1) respectively represent the amounts (moles) of the structural unit (a), the structural unit (b), the structural unit (c) and the structural unit (a1) present.

The polyfunctional vinyl aromatic copolymer of the present invention preferably contains 5 to 35 mol% of the structural unit (a) derived from a divinylaromatic compound.

When the structural unit includes only the structural unit (a), the structural unit (b) and the structural unit (c), the mole fraction of the structural unit (a) is 0.05 to 0.35 relative to the total of the structural unit (a), the structural unit (b) and the structural unit (c). The mole fraction is calculated by the following formula (13).

(a)/[(a)+(b)+(c)]…(13)

(wherein (a), (b), and (c) have the same meanings as in formula (2))

The lower limit of the molar fraction is preferably 0.06, more preferably 0.07. The upper limit is preferably 0.30, and more preferably 0.25.

When a structural unit other than the structural unit (a), the structural unit (b), and the structural unit (c) is included, the lower limit is preferably 0.02, more preferably 0.05, and still more preferably 0.07. The upper limit is preferably 0.35, more preferably 0.30, and still more preferably 0.25.

On the other hand, the mole fraction of the structural unit (b) derived from the monovinyl aromatic compound is 0.05 to 0.25. The preferred lower limit is 0.07. The upper limit is preferably 0.23, more preferably 0.20.

The molar fraction of the structural unit (c) derived from the cycloolefin monomer is 0.40 to 0.90, and the lower limit is preferably 0.45, more preferably 0.50, and still more preferably 0.65. The upper limit is preferably 0.86, and more preferably 0.80.

When only the structural unit (a), the structural unit (b), and the structural unit (c) are contained, the mole fraction of the structural unit (b) is calculated by the following formula (14), and the mole fraction of the structural unit (c) is calculated by the following formula (15).

(b)/[(a)+(b)+(c)]…(14)

(c)/[(a)+(b)+(c)]…(15)

(wherein (a), (b), and (c) have the same meanings as those of formula (12))

When a structural unit other than the structural unit (a), the structural unit (b) and the structural unit (c) is included, the preferable mole fraction of the structural unit (b) or the structural unit (c) is also in the above range.

The structural unit (a) derived from a divinyl aromatic compound contains a vinyl group as a branching component for exhibiting copolymerization reactivity with a conjugated diene compound, while the structural unit (b) derived from a monovinyl aromatic compound does not have a vinyl group participating in a curing reaction, and therefore moldability, compatibility, and the like are imparted. Further, the amount of the structural unit (c) derived from the cycloolefin monomer introduced affects the molecular weight and the molecular weight distribution of the polyfunctional vinyl aromatic copolymer, and therefore, reactivity, ease of gel formation, and compatibility are imparted. Therefore, if the mole fraction of the structural unit (a) is less than 0.05, the heat resistance of the cured product is insufficient, and if the mole fraction of the structural unit (a) exceeds 0.35, the moldability is lowered. When the mole fraction of the structural unit (b) exceeds 0.25, the heat resistance is lowered, and when the mole fraction of the structural unit (b) is less than 0.05, the moldability is lowered. On the other hand, if the mole fraction of the structural unit (c) exceeds 0.90, the heat resistance is lowered, and if the mole fraction of the structural unit (c) is less than 0.40, the moldability is lowered.

The Mn (number average molecular weight in terms of standard polystyrene measured by gel permeation chromatography) of the polyfunctional vinyl aromatic copolymer of the present invention is preferably 300 to 100,000, more preferably 400 to 50,000, and still more preferably 500 to 10,000. If Mn is less than 300, the amount of the monofunctional copolymer contained in the copolymer increases, and therefore the copolymerization reactivity with the conjugated diene compound tends to decrease, and if Mn exceeds 100,000, gel is likely to be formed, and the moldability and tensile elongation at break tend to decrease. The value of the molecular weight distribution (Mw/Mn) is preferably 10.0 or less, more preferably 8.0 or less, and still more preferably 1.0 to 7.0. Most preferably 1.3 to 6.0. When Mw/Mn exceeds 10.0, the processability of the copolymer rubber tends to be deteriorated, and gelation tends to occur.

The soluble polyfunctional vinyl aromatic copolymer of the present invention is soluble in a solvent selected from toluene, xylene, tetrahydrofuran, dichloroethane or chloroform, but advantageously is soluble in any of the solvents. Since the copolymer is a polyfunctional copolymer that can be dissolved in a solvent, it is necessary that a part of vinyl groups of divinylbenzene remain without being crosslinked and have an appropriate branching degree. Such a copolymer or a method for producing the copolymer is known from the patent documents and the like. Further, 50g or more of the copolymer may be dissolved in 100g of the solvent. More preferably 80g or more.

The polyfunctional vinyl aromatic copolymer of the second invention will be explained.

The polyfunctional vinyl aromatic copolymer of the present invention contains a structural unit (a) derived from a divinyl aromatic compound and a structural unit (b) derived from a monovinyl aromatic compound.

At least a part of the structural unit (a) includes a crosslinking structural unit (a2) represented by the formula (2) and a vinyl group-containing structural unit (a1) represented by the formula (1).

The molar fraction (also referred to as the degree of crosslinking) of the divinylaromatic compound-derived crosslinking structural unit (a2) relative to the structural unit (a) is in the range of 0.05 to 0.50. The molar fraction of the vinyl group-containing structural unit (a1) relative to the total of the structural unit (a) and the structural unit (b) is in the range of 0.001 to 0.35.

The crosslinking degree of the crosslinking structural unit (a2) is in the range of 0.05 to 0.50, and a preferable lower limit is 0.06, and more preferably 0.07. The upper limit is preferably 0.45, and more preferably 0.40. Particularly preferably 0.35 and most preferably 0.30. By setting the above range, a copolymer rubber can be obtained which has excellent reactivity when copolymerized with a conjugated diene compound while maintaining solubility, has excellent compatibility with a diene rubber, and has excellent processability, tensile strength, and abrasion resistance. The crosslinking degree of the polyfunctional vinyl aromatic copolymer of the present invention is a parameter which can be arbitrarily controlled and changed independently of the vinyl group-containing structural unit (a1) represented by the formula (1) described later, but when the crosslinking degree is less than 0.05, the crosslinking degree of the polyfunctional vinyl aromatic copolymer is small, and therefore, the crosslinking reaction tends to occur in the molecule of the vinyl group-containing structural unit (a1) represented by the formula (1), and microgel tends to be formed when the copolymer is copolymerized with a conjugated diene compound or the like. On the other hand, when the crosslinking degree is more than 0.50, the molecular weight of the polyfunctional vinyl aromatic copolymer itself tends to be increased and the molecular weight distribution tends to be broadened, so that the abrasion resistance tends to be lowered.

The structural unit (a) derived from a divinylaromatic compound may have a plurality of structurally different structural units such as a structural unit in which only one vinyl group is reacted and a structural unit in which two vinyl groups are reacted, and the structural unit (a1) may include a structural unit in which only one vinyl group is reacted in the range of 0.001 to 0.35 in terms of the molar fraction, that is, a structural unit containing a vinyl group represented by the formula (1).

The preferred lower limit is 0.005, more preferably 0.01. The upper limit is preferably 0.30, and more preferably 0.20. By setting the above range, a copolymer rubber can be obtained which has excellent reactivity when copolymerized with a conjugated diene compound while maintaining solubility, has excellent compatibility with a diene rubber, and has excellent processability, tensile strength, and abrasion resistance. When the molar fraction is less than 0.001, copolymerization reactivity with a conjugated diene compound or the like tends to be lowered, and when the molar fraction is more than 0.35, microgel tends to be formed at the time of copolymerization.

Here, the mole fraction is a mole fraction of the vinyl group-containing structural unit (a1) with respect to the total of the structural unit (a) and the structural unit (b), and is calculated by the following formula (23).

(a1)/[(a)+(b)] (23)

Here, (a), (b) and (a1) respectively represent the amounts (moles) of the structural unit (a), the structural unit (b) and the structural unit (a1) present.

The polyfunctional vinyl aromatic copolymer of the present invention contains 0.5 to 40 mol% of the structural unit (a) derived from a divinyl aromatic compound.

When the structural unit includes only the structural unit (a) and the structural unit (b), the mole fraction of the structural unit (a) is 0.005 to 0.40 relative to the total of the structural unit (a) and the structural unit (b). The mole fraction is calculated by the following formula (24).

(a)/[(a)+(b)] (24)

(wherein (a) and (b) have the same meanings as in formula (23))

A preferred lower limit of the mole fraction is 0.006, more preferably 0.007. The upper limit is preferably 0.30, and more preferably 0.25.

When a structural unit other than the structural unit (a) and the structural unit (b) is included, the lower limit of the content is preferably 0.2 mol%, more preferably 0.5 mol%, and still more preferably 0.7 mol%. The upper limit is preferably 35 mol%, more preferably 30 mol%, and still more preferably 25 mol%.

On the other hand, the mole fraction of the structural unit (b) derived from the monovinyl aromatic compound is 0.60 to 0.995. The preferred lower limit is 0.70. A more preferred lower limit is 0.75. The upper limit is preferably 0.994, more preferably 0.993.

When only the structural unit (a) and the structural unit (b) are contained, the mole fraction of the structural unit (b) is calculated by the following formula (25).

(b)/[(a)+(b)] (25)

(wherein (a) and (b) have the same meanings as in formula (23))

When structural units other than structural unit (a) and structural unit (b) are included, the preferred mole fraction of structural unit (b) is also in the above range.

The polyfunctional vinyl aromatic copolymer of the present invention may contain not only the structural unit but also other structural units. The details of the other structural elements can be understood from the description of the manufacturing method.

The multifunctional vinyl aromatic copolymer of the present invention has an Mn (number average molecular weight in terms of standard polystyrene measured by gel permeation chromatography) of 1,000 to 50,000, preferably 1,200 to 45,000, and more preferably 1,400 to 30,000. More preferably 1,600 to 20,000, and most preferably 2,000 to 10,000. When Mn is less than 1,000, the amount of the monofunctional copolymer contained in the copolymer increases, and therefore the copolymerization reactivity with the conjugated diene compound tends to decrease, and when Mn exceeds 50,000, not only gelation tends to occur, but also the moldability and tensile elongation at break tend to decrease. The molecular weight distribution is 8.0 or less, preferably 7.0 or less, and more preferably 1.3 to 6.0. When Mw/Mn exceeds 8.0, not only the processability of the copolymer rubber tends to deteriorate, but also gelation tends to occur.

The polyfunctional vinyl aromatic copolymer of the present invention is soluble in a solvent selected from the group consisting of toluene, xylene, tetrahydrofuran, dichloroethane or chloroform, but advantageously is soluble in any of the solvents. Since the copolymer is a polyfunctional copolymer that can be dissolved in a solvent, it is necessary that a part of vinyl groups of divinylbenzene remain without being crosslinked and have an appropriate branching degree. Such a copolymer or a method for producing the copolymer is known from the patent documents and the like. Further, 50g or more of the copolymer may be dissolved in 100g of the solvent. More preferably 80g or more.

The polyfunctional vinyl aromatic copolymer of the present invention may have a haze value (haze) of 0.1 or less in a toluene solution thereof. Here, the haze value is a haze value measured by using an integrating sphere type light transmittance measuring apparatus using toluene as a reference sample, in which a solution prepared by dissolving 0.5g of a polyfunctional vinyl aromatic copolymer in 100g of toluene is placed in a quartz cell.

The haze value is also related to the evaluation of solubility in a solvent, and a low haze value means excellent solubility or less gel.

The polyfunctional vinyl aromatic copolymer of the third invention will be explained.

The polyfunctional vinyl aromatic copolymer of the present invention contains a structural unit (a) derived from a divinyl aromatic compound, a structural unit (b) derived from a monovinyl aromatic compound having no substituent at the α -position, and a structural unit (c) derived from an α, α -disubstituted olefin compound.

The molar fraction (also referred to as the degree of crosslinking)) of the crosslinking structural unit (a2) derived from a divinylaromatic compound relative to the proportion of the structural unit (a) is in the range of 0.05 to 0.60. The molar fraction of the vinyl group-containing structural unit (a1) to the total of the structural unit (a), the structural unit (b), and the structural unit (c) is in the range of 0.001 to 0.60.

The crosslinking degree of the crosslinking structural unit (a2) is in the range of 0.05 to 0.60, and a preferable lower limit is 0.06, and more preferably 0.07. The upper limit is preferably 0.55, more preferably 0.50. Particularly preferably 0.45 and most preferably 0.40. The most preferable range is 0.20 to 0.40. The crosslinking degree and the vinyl group-containing structural unit (a1) represented by the formula (1) are parameters that can be arbitrarily controlled and changed independently, but when the crosslinking degree of the crosslinking structural unit (a2) is less than 0.05, the crosslinking degree of the polyfunctional vinyl aromatic copolymer is small, and therefore the crosslinking reaction easily occurs in the molecule of the vinyl group-containing structural unit (a1) represented by the formula (1), and microgel tends to be formed when copolymerized with a conjugated diene compound or the like. On the other hand, when the crosslinking degree is more than 0.60, the molecular weight of the polyfunctional vinyl aromatic copolymer itself tends to be increased and the molecular weight distribution tends to be broadened, so that the abrasion resistance tends to be lowered.

The structural unit (a) derived from a divinylaromatic compound may have a plurality of structurally different structural units such as a structural unit in which only one vinyl group is reacted and a structural unit in which two vinyl groups are reacted, and the structural unit (a1) may include a structural unit in which only one vinyl group is reacted in the range of 0.001 to 0.60 in terms of the molar fraction, that is, a structural unit containing a vinyl group represented by the formula (1).

The preferred lower limit is 0.005, more preferably 0.01. The upper limit is preferably 0.55, more preferably 0.50. The most preferable range is 0.10 to 0.50. By setting the above range, a copolymer rubber can be obtained which has excellent reactivity when copolymerized with a conjugated diene compound while maintaining solubility, has excellent compatibility with a diene rubber, and has excellent processability, tensile strength, and abrasion resistance. When the molar fraction is less than 0.001, copolymerization reactivity with a conjugated diene compound or the like tends to be lowered, and when the molar fraction is more than 0.60, microgel tends to be formed at the time of copolymerization.

(a1)/[(a)+(b)+(c)] (33)

Here, (a), (b), (c) and (a1) respectively represent the amounts (moles) of the structural unit (a), the structural unit (b), the structural unit (c) and the structural unit (a1) present.

The polyfunctional vinyl aromatic copolymer of the present invention contains 0.5 to 60 mol% of the structural unit (a) derived from a divinyl aromatic compound.

When the structural unit includes only the structural unit (a), the structural unit (b) and the structural unit (c), the mole fraction of the structural unit (a) is 0.005 to 0.75 relative to the total of the structural unit (a), the structural unit (b) and the structural unit (c). The mole fraction is calculated by the following formula (34).

(a)/[(a)+(b)+(c)] (34)

(wherein (a), (b) and (c) have the same meanings as those of formula (33))

A preferred lower limit of the mole fraction is 0.006, more preferably 0.007. The upper limit is preferably 0.70, more preferably 0.60. Preferably 0.10 to 0.55.

When a structural unit other than the structural unit (a), the structural unit (b), and the structural unit (c) is included, the lower limit of the content is preferably 0.2 mol%, more preferably 0.5 mol%, and still more preferably 0.7 mol%. The upper limit is preferably 50 mol%, more preferably 45 mol%, and still more preferably 40 mol%.

The polyfunctional vinyl aromatic copolymer of the present invention contains 5.0 to 75 mol% of a structural unit (b) derived from a monovinyl aromatic compound having no substituent at the α -position. The molar fraction is 0.05 to 0.75. The preferred lower limit is 0.06. A more preferred lower limit is 0.07. The upper limit is preferably 0.70, more preferably 0.65. Preferably 0.30 to 0.60.

When only the structural unit (a), the structural unit (b) and the structural unit (c) are contained, the mole fraction of the structural unit (b) is calculated by the following formula (35).

(b)/[(a)+(b)+(c)] (35)

(wherein (a), (b) and (c) have the same meanings as those of formula (33))

The polyfunctional vinyl aromatic copolymer of the present invention contains 5.0 to 75 mol% of a structural unit (c) derived from an α, α -disubstituted olefin compound. The molar fraction is 0.05 to 0.75. The preferred lower limit is 0.06. A more preferred lower limit is 0.07. The upper limit is preferably 0.70, more preferably 0.65. Preferably 0.10 to 0.40.

When only the structural unit (a), the structural unit (b) and the structural unit (c) are contained, the mole fraction of the structural unit (c) is calculated by the following formula (36).

(c)/[(a)+(b)+(c)] (36)

(wherein (a), (b) and (c) have the same meanings as those of formula (33))

When the structural unit (a), the structural unit (b) and a structural unit other than the structural unit (c) are included, the preferable mole fraction of the structural unit (c) is also in the above range.

Further, if the mole fraction of the structural unit (a) is less than 0.005, the heat resistance of the cured product is insufficient, and if the mole fraction of the structural unit (a) exceeds 0.75, the moldability is lowered. When the mole fraction of the structural unit (b) exceeds 0.75, the heat resistance is lowered, and when the mole fraction of the structural unit (b) is less than 0.05, the moldability is lowered. On the other hand, if the mole fraction of the structural unit (c) exceeds 0.75, the heat resistance is lowered, and if the mole fraction of the structural unit (c) is less than 0.05, the molecular weight is increased, and the compatibility with other resins or the molding processability is lowered.

The multifunctional vinyl aromatic copolymer of the present invention has Mn (number average molecular weight in terms of standard polystyrene measured by gel permeation chromatography) of 300 to 50,000, preferably 500 to 45,000, and more preferably 600 to 40,000. More preferably 700 to 35,000, and most preferably 800 to 30,000. Preferably 900 to 3,000. If Mn is less than 300, the amount of the monofunctional copolymer contained in the copolymer increases, and therefore the copolymerization reactivity with the conjugated diene compound tends to decrease, and if Mn exceeds 50,000, not only gelation tends to occur, but also the moldability and tensile elongation at break tend to decrease. The molecular weight distribution is 10.0 or less, preferably 9.0 or less, and more preferably 1.3 to 8.0. Most preferably 2.0 to 6.0. When Mw/Mn exceeds 10.0, not only the processability of the copolymer rubber tends to deteriorate, but also gelation tends to occur.

Next, the method for producing the polyfunctional vinyl aromatic copolymer according to the first, second, and third aspects of the present invention will be described. The polyfunctional vinyl aromatic copolymer of the present invention can be advantageously produced by the production method.

In the production method of the present invention, polymerization can be carried out at a temperature of 20 to 60 ℃ in the presence of a Lewis acid catalyst in a homogeneous solvent in which a polymerization raw material containing essential components such as a divinyl aromatic compound and a monovinyl aromatic compound is dissolved in a solvent having a dielectric constant of 2.0 to 15.0.

The divinyl aromatic compound branches the copolymer to form a polyfunctional group, and plays an important role as a crosslinking component for generating branching when the copolymer is copolymerized with the conjugated diene compound. As examples of the divinylaromatic compound, divinylbenzene (including isomers), divinylnaphthalene (including isomers), and divinylbiphenyl (including isomers) are preferably used, but not limited thereto. In addition, these may be used alone or in combination of two or more. From the viewpoint of moldability, divinylbenzene (an intermediate, a para-isomer or an isomer mixture of these) is more preferable.

The monovinyl aromatic compound improves the solvent solubility, compatibility, and processability of the copolymer.

Examples of the monovinyl aromatic compound include vinyl aromatic compounds such as styrene, vinyl naphthalene, and vinyl biphenyl; nuclear alkyl substituted vinyl aromatic compounds such as o-methylstyrene, m-methylstyrene, p-methylstyrene, o, p-dimethylstyrene, o-ethylvinylbenzene, m-ethylvinylbenzene, p-ethylvinylbenzene, etc.; etc., but are not limited to these. In order to prevent gelation of the copolymer and improve solubility in a solvent, compatibility and processability, it is particularly preferable to use styrene, ethylvinylbenzene (including isomers), ethylvinylbiphenyl (including isomers) and ethylvinylnaphthalene (including isomers) from the viewpoints of cost and acquisition easiness. From the viewpoint of compatibility and cost, styrene, ethylvinylbenzene (intermediate, para-isomer, or an isomer mixture of these) are more preferable.

Preferred are compounds having no substituent at the alpha position.

In the first invention, the cycloolefin monomer has an aromatic condensed ring structure, but it also functions as a chain transfer agent, and controls the molecular weight and molecular weight distribution of the copolymer during polymerization, thereby improving solvent solubility and processability while maintaining high dielectric characteristics of the hydrocarbon resin material.

The cycloolefin monomer may be any monomer as long as it contains an aromatic ring and a cycloolefin ring condensed therewith, and the cycloolefin ring may have an unsaturated bond capable of cationic polymerization and may contain a different kind of atom such as an oxygen atom or a sulfur atom as a ring-constituting atom. The aromatic ring or cycloolefin ring may have a substituent such as an alkyl group, an alkoxy group, or an acyl group.

Preferred examples of the cycloolefin-based monomer include monomers selected from the group consisting of indene-based compounds, acenaphthene-based compounds, benzofuran-based compounds, and benzothiophene-based compounds.

The indene compound may be at least one compound selected from the group consisting of indenes, alkylindenes, halogenated indenes, arylindenes, alkoxyindenes, alkoxycarbonylindenes, acyloxyindenes, alkylsilylindenes and alkylstannylalkylindenes.

The acenaphthene compound includes at least one compound selected from the group consisting of acenaphthene, alkyl acenaphthenes, halogenated acenaphthenes, aryl acenaphthenes, alkoxy acenaphthenes, alkoxycarbonyl acenaphthenes, acyloxy acenaphthenes, alkylsilyl acenaphthenes, and alkyl stannyl acenaphthenes.

The benzofuran compounds and benzothiophene compounds may be benzofuran compounds and benzothiophene compounds modified with the same substituent as the indene compounds and the acenaphthene compounds, as well as benzofuran and benzothiophene compounds. The benzofuran compound may be 1-benzofuran or 2-benzofuran. The same is true for benzothiophenes.

The cycloolefin monomers specifically exemplified above may be used singly or in combination of two or more. Among these cycloolefin monomers, indene compounds and acenaphthene compounds are preferably used from the viewpoint of ease of industrial acquisition, dielectric properties, and high molecular weight control effect of the copolymer of the present invention. Indene is most preferably used from the viewpoint of high or low copolymerization reactivity and the effect of controlling the molecular weight.

In the third invention, the α, α -disubstituted olefin compound has a function of controlling the molecular weight of the copolymer, thereby improving solvent solubility, compatibility and processability. Examples of the α, α -disubstituted olefin compounds include compounds selected from the group consisting of isobutylene, diisobutylene, 2-methyl-1-butene, 2-methyl-1-pentene, 1-methyl-1-cyclopentene, 2-methyl-1-hexene, 1-methyl-1-cyclohexene, 2-methyl-1-heptene, 2-methyl-1-octene, 2-methyl-1-decene, 2-methyl-1-dodecene, 2-methyl-1-tetradecene, 2-methyl-1-hexadecene, 2-methyl-1-octadecene, 2-methyl-1-eicosene, 2-methyl-1-docosene, and mixtures thereof, 2-methyl-1-tetracosene, alpha-methylstyrene, but not limited thereto. In order to control the molecular weight and molecular weight distribution of the copolymer, prevent the formation of gel, and improve the solubility in a solvent, compatibility, and processability, it is preferable to use an α, α -disubstituted olefin compound substituted with an aliphatic group, such as isobutylene, diisobutylene, 2-methyl-1-pentene, 2-methyl-1-hexene, and isoprene, or if the α, α -disubstituted olefin compound is substituted with an aromatic group, α -methylstyrene, from the viewpoint of cost and ease of acquisition. In terms of ease of production and cost, isobutylene, diisobutylene, and α -methylstyrene are more preferable.

In the method for producing the copolymer of the present invention, the structural unit (e) derived from another monomer may be introduced into the copolymer by using not only essential components such as a divinyl aromatic compound and a monovinyl aromatic compound but also other monomers such as a trivinyl aromatic compound, a trivinyl aliphatic compound, a divinyl aliphatic compound, and a monovinyl aliphatic compound, within a range not to impair the effects of the present invention.

Specific examples of the other monomer include, but are not limited to, 1,3, 5-trivinylbenzene, 1,3, 5-trivinylnaphthalene, 1,2, 4-trivinylcyclohexane, ethylene glycol diacrylate, butadiene, and the like. These may be used alone or in combination of two or more. The other monomers may be used in the range of less than 30 mol% of all the monomers. Accordingly, the structural unit (e) derived from another monomer is in a range of less than 30 mol% with respect to the total amount of structural units in the copolymer.

In the method for producing a copolymer of the present invention, a copolymer is produced by polymerizing a monomer containing an essential component such as a divinyl aromatic compound or a monovinyl aromatic compound and, if necessary, other monomers in the presence of a lewis acid catalyst.

In the first invention, the ratio of each component as a monomer to be used may be in the following range with respect to 100 mol% of the total of the divinylaromatic compound, the monovinylaromatic compound and the cycloolefin monomer.

Divinyl aromatic compound: 5 to 35 mol%, preferably 6 to 30 mol%, and more preferably 7 to 25 mol%.

Monovinyl aromatic compound: 5 to 25 mol%, preferably 6 to 23 mol%, and more preferably 7 to 20 mol%.

Cycloolefin monomer: 40 to 90 mol%, preferably 45 to 86 mol%, and more preferably 50 to 80 mol%.

In the second invention, the ratio of each component as a monomer to be used may be set in the following range with respect to 100 mol% of the total of the divinyl aromatic compound and the monovinyl aromatic compound.

Divinyl aromatic compound: 0.2 to 45 mol%, preferably 0.3 to 40 mol%, and more preferably 0.4 to 35 mol%.

Monovinyl aromatic compound: 55 to 99.8 mol%, preferably 60 to 99.7 mol%, and more preferably 65 to 99.6 mol%.

In the third invention, the ratio of each component as a monomer can be set in the following range with respect to 100 mol% of the total of the divinylaromatic compound, the monovinylaromatic compound having no substituent at the α -position, and the α, α -disubstituted olefin compound.

Divinyl aromatic compound: 0.2 to 75 mol%, preferably 0.3 to 65 mol%, more preferably 0.4 to 55 mol%, most preferably 5 to 50 mol%.

Monovinyl aromatic compound having no substituent at α position: 7 to 99 mol%, preferably 10 to 95 mol%, and more preferably 15 to 90 mol%.

α, α -disubstituted alkene compounds: 5 to 99 mol%, preferably 10 to 95 mol%, more preferably 15 to 90 mol%, most preferably 20 to 60 mol%.

The lewis acid catalyst (e) used herein is not particularly limited as long as it is a compound containing a metal ion (acid) and a ligand (base) and can receive an electron pair. Among the lewis acid catalysts, from the viewpoint of thermal decomposition resistance of the obtained copolymer, a metal fluoride or a complex thereof is preferable, and particularly, a divalent to hexavalent metal fluoride or a complex thereof such as B, Al, Ga, In, Si, Ge, Sn, Pb, Sb, Bi, Ti, W, Zn, Fe, and V is preferable. These catalysts may be used alone or in combination of two or more. From the viewpoint of controlling the molecular weight and molecular weight distribution of the obtained copolymer and polymerization activity, it is most preferable to use an ether complex of boron trifluoride. Here, as the ether of the ether complex, diethyl ether, dimethyl ether, and the like are mentioned.

The lewis acid catalyst may be used in a range of 0.001 to 100 moles, more preferably 0.01 to 50 moles, based on 100 moles of the total of all monomer components. Most preferably from 0.1 to 10 mol. When the amount exceeds 100 mol, the polymerization rate becomes too high, and it becomes difficult to control the molecular weight distribution. When the amount is less than 0.001 mol, the polymerization rate becomes too low, which leads to an increase in cost, and thus the method is not suitable for industrial practice.

In the method for producing the copolymer of the present invention, one or more kinds of the lewis basic compounds may be used as a cocatalyst as desired.

Specific examples of the lewis basic compound include the following compounds.

1) Ester compounds such as ethyl acetate, butyl acetate, phenyl acetate, and methyl propionate;

2) thioester compounds such as methyl mercaptopropionate and ethyl mercaptopropionate;

3) ketone compounds such as methyl ethyl ketone, methyl isobutyl ketone, and benzophenone;

4) amine compounds such as methylamine, ethylamine, propylamine, butylamine, cyclohexylamine, methylethylamine, dimethylamine, diethylamine, dipropylamine and dibutylamine;

5) ether compounds such as diethyl ether and tetrahydrofuran;

6) thioether compounds such as diethyl sulfide and diphenyl sulfide; and

7) phosphine compounds such as tripropylphosphine, tributylphosphine, trihexylphosphine, tricyclohexylphosphine, trioctylphosphine, vinylphosphine, propenylphosphine, cyclohexenylphosphine, dienylphosphine, and trienylphosphine.

Among these, ester-based compounds and ketone-based compounds are preferably used in terms of easily controlling the polymerization rate and the molecular weight distribution of the polymer by cooperating with the lewis acid catalyst.

One or two or more of these lewis basic compounds may be used.

When the lewis basic compound as the cocatalyst component is used in the polymerization reaction, the interaction between the carbocation as the active species and the counter anion is controlled by the lewis acid catalyst as the counter anion, thereby adjusting the relative reaction frequency with the cycloolefin compound, the divinylaromatic compound and the monovinylaromatic compound functioning as the chain transfer agent. In general, by adding a lewis basic compound, the interaction between the carbocation as the active species and the counter anion is enhanced, and therefore, excessive insertion reaction of the divinyl aromatic compound and the monovinyl aromatic compound is suppressed, chain transfer reaction after the insertion reaction of the cycloolefin compound is likely to occur, and control of the molecular weight becomes easy.

The amount of the Lewis basic compound as the cocatalyst is 0.005 to 500 mol, more preferably 0.01 to 100 mol, and still more preferably 0.1 to 50 mol, based on 100 mol of the total of all monomers. When the amount is within the above range, the polymerization rate is appropriately maintained, and at the same time, the selectivity of the reaction between monomers is improved, and a copolymer excellent in productivity, in which excessive increase or decrease in molecular weight is suppressed, and which is excellent in moldability can be obtained.

The polymerization reaction is carried out by cationic copolymerization in a homogeneous solvent obtained by dissolving a polymerization raw material comprising the monomer mixture and a Lewis acid catalyst in a solvent having a dielectric constant of 2.0 to 15.0 at a temperature of 20 to 120 ℃.

The solvent is a compound which does not substantially inhibit cationic polymerization, and may be an organic solvent which dissolves the catalyst, the polymerization additive, the cocatalyst, the monomer and the produced vinyl aromatic copolymer to form a uniform solution, and has a dielectric constant in the range of 2.0 to 15.0, and may be used alone or in combination of two or more. If the dielectric constant of the solvent is less than 2.0, the molecular weight distribution becomes broad, which is not preferable, and if the dielectric constant of the solvent exceeds 15.0, the polymerization rate decreases.

The organic solvent is particularly preferably toluene, xylene, n-hexane, cyclohexane, methylcyclohexane or ethylcyclohexane from the viewpoint of balance between polymerization activity and solubility. In addition, the amount of the solvent used is determined so that the concentration of the copolymer in the polymerization solution at the end of the polymerization becomes 1 to 90 wt%, preferably 10 to 80 wt%, and particularly preferably 20 to 70 wt%, in view of the viscosity of the polymerization solution obtained and the easiness of heat removal. When the concentration is less than 1 wt%, the polymerization efficiency is low, which leads to an increase in cost, and when the concentration exceeds 90 wt%, the molecular weight and the molecular weight distribution increase, which leads to a decrease in molding processability.

In the production of soluble polyfunctional vinyl aromatic polymers, it is necessary to carry out the polymerization at a temperature of from 20 ℃ to 120 ℃. Preferably from 40 ℃ to 100 ℃. When the polymerization temperature exceeds 120 ℃, the reaction selectivity is lowered, which causes problems such as increase in molecular weight distribution and formation of gel, and when the polymerization temperature is less than 20 ℃, the catalyst activity is remarkably lowered, which requires addition of a large amount of catalyst.

The method for recovering the copolymer after the termination of the polymerization reaction is not particularly limited, and a commonly used method such as a heat concentration method, a steam stripping method, and precipitation in a poor solvent can be used.

The polyfunctional vinyl aromatic copolymer obtained by the production method contains a structural unit (a) derived from a divinyl aromatic compound, a structural unit (b) derived from a monovinyl aromatic compound, and a structural unit (c) derived from a cycloolefin monomer having an aromatic fused ring structure, and at least a part of the structural unit (a) derived from the divinyl aromatic compound is present as a vinyl group-containing structural unit (a1) represented by the formula (1). Furthermore, it can be dissolved in toluene, xylene, tetrahydrofuran, dichloroethane or chloroform.

The polyfunctional vinyl aromatic copolymer of the first, second, and third aspects of the present invention has unreacted vinyl groups, and therefore can be cured and molded by polymerization alone, but may be copolymerized with another polymerizable resin or monomer to form a second copolymer. In particular, the polyfunctional vinyl aromatic copolymer of the present invention is excellent because it is copolymerized with another monomer containing a conjugated diene to obtain a conjugated diene copolymer (rubber).

The polyfunctional vinyl aromatic copolymer (a) of the present invention as a raw material is copolymerized with 1) a conjugated diene compound (B), or 2) a conjugated diene compound (B) and an aromatic vinyl compound (C), thereby obtaining the conjugated diene copolymer of the present invention. When the aromatic vinyl compound (C) is not used, a diene rubber such as a butadiene rubber or an isoprene rubber can be obtained, and when the aromatic vinyl compound (C) is used, a conjugated diene copolymer such as SBR can be obtained. The conjugated diene copolymer is also referred to as a copolymer rubber because it exhibits the characteristics of a rubber.

In the polymerization step for obtaining the conjugated diene copolymer, the following method may be employed: a method (method I) in which a polyfunctional anionic polymerization initiator is prepared in advance in a predetermined reactor by reacting the polyfunctional vinyl aromatic copolymer (a) of the present invention with an organolithium compound, and the prepared polyfunctional anionic polymerization initiator is supplied to a reactor in which a conjugated diene compound is polymerized to carry out polymerization or copolymerization reaction; a method (method II) in which a raw material comprising the polyfunctional vinyl aromatic copolymer (a) and the conjugated diene compound (B), or the polyfunctional vinyl aromatic copolymer (a), the conjugated diene compound (B), and the aromatic vinyl compound (C) and an organolithium compound (or an anionic polymerization initiator) are supplied in batch to a reactor for copolymerization to perform a copolymerization reaction; and a method (method III) for synthesizing a conjugated diene copolymer by supplying the conjugated diene compound (B), or the conjugated diene compound (B) and the aromatic vinyl compound (C) to a predetermined reactor to polymerize the conjugated diene compound, or to copolymerize the conjugated diene compound and the aromatic vinyl compound, and reacting the polymer of the conjugated diene compound having an active end, or the copolymer of the conjugated diene compound and the aromatic vinyl compound, which is produced in the reactor, with the polyfunctional vinyl aromatic copolymer (a).

Of these polymerization methods, the method I is preferable in terms of the efficiency of the copolymerization reaction with the polyfunctional vinyl aromatic copolymer (A) of the present invention.

Examples of the conjugated diene compound (B) include: 1, 3-butadiene, isoprene, 2, 3-dimethyl-1, 3-butadiene, 1, 3-pentadiene, 3-methyl-1, 3-pentadiene, 1, 3-heptadiene, 1, 3-hexadiene, and the like. Of these, 1, 3-butadiene and isoprene are preferable. These may be used alone or in combination of two or more.

As the aromatic vinyl compound (C), styrene, α -methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, vinylxylene, 4-cyclohexylstyrene, 2,4, 6-trimethylstyrene, tert-butoxydimethylsilylstyrene, isopropoxydimethylsilylstyrene and the like can be used alone or in combination, and of these, styrene is particularly preferable.

In the case of using 1, 3-butadiene as the conjugated diene compound (B) and styrene as the aromatic vinyl compound, a so-called styrene-butadiene rubber (SBR) is obtained. In addition, when styrene is not used as the aromatic vinyl compound, in the case of using 1, 3-butadiene as the conjugated diene compound (B), a so-called Butadiene Rubber (BR) is obtained. When isoprene is used as the structural unit of the conjugated diene compound (B) and no aromatic vinyl compound (C), Isoprene Rubber (IR) is obtained. Among them, a styrene-butadiene rubber (SBR) structure is particularly preferable because it is excellent in wear resistance, heat resistance and aging resistance.

The organolithium compound used as an initiator is not particularly limited, and examples thereof include: mono-organolithium compounds such as n-butyllithium, sec-butyllithium, tert-butyllithium, n-propyllithium, isopropyllithium, and benzyllithium; and polyfunctional organic lithium compounds such as 1, 4-dilithiobutane, 1, 5-dilithiopentane, 1, 6-dilithiohexane, 1, 10-dilithiodecane, 1-dilithiodiphenylene, dilithiobutapolybutadiene, dilithiopolypolyisoprene, 1, 4-dilithiobenzene, 1, 2-dilithio-1, 2-diphenylethane, 1, 4-dilithio-2-ethylcyclohexane, 1,3, 5-trilithiobenzene, and 1,3, 5-trilithio-2, 4, 6-triethylbenzene. Among these, a mono-organolithium compound of n-butyllithium, sec-butyllithium, and tert-butyllithium is preferable.

In the production of the conjugated diene copolymer, the following polar compound is preferably added as a vinylating agent for controlling the microstructure of the conjugated diene portion, and in order to improve the polymerization rate and the like.

Examples of the polar compound include: ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2, 2-bis (2-tetrahydrofuryl) propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine and quinuclidine; alkali metal alkoxide compounds such as potassium tert-butoxide, sodium tert-butoxide, and sodium pentoxide; phosphine compounds such as triphenylphosphine, and the like. These polar compounds may be used alone, or two or more of them may be used in combination.

The amount of the polar compound to be used is selected depending on the purpose and the degree of the effect of the obtained conjugated diene copolymer composition, and is preferably 0.005 to 100 mol based on 1 mol of the organolithium compound as an initiator.

The conjugated diene copolymer is preferably polymerized in a predetermined solvent. Particularly preferably in a solvent satisfying the dielectric constant. The solvent is not particularly limited, and a hydrocarbon solvent such as a saturated hydrocarbon or an aromatic hydrocarbon can be used. Specific examples thereof include aliphatic hydrocarbons such as butane, pentane, hexane and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene, and mixtures thereof.

It is preferable that the conjugated diene compound and the polymerization solvent are treated with an organic metal compound in advance, either individually or as a mixture. Thus, the allenes or acetylenes contained in the conjugated diene compound or the polymerization solvent can be treated. As a result, a polymer having a high concentration of active ends can be obtained, and a high modification ratio can be achieved.

The polymerization active terminal of the conjugated diene copolymer of the present invention may be further reacted with a modifier. In the present specification, the conjugated diene copolymer obtained by the above reaction is also referred to as a modified conjugated diene copolymer.

As the modifier (also referred to as "terminal modifier") used in the present embodiment, a compound having a functional group reactive with the polymerization active terminal of the conjugated diene copolymer is used. The terminal modifier is not particularly limited, and when a monofunctional compound is used, a linear both-terminal modified diene copolymer can be obtained, and when a polyfunctional compound is used, a branched both-terminal modified diene copolymer can be obtained. It is preferable to use a monofunctional or polyfunctional compound containing at least one element selected from the group consisting of nitrogen, silicon, tin, phosphorus, oxygen, sulfur, halogen as the terminal modifier. Further, an onium structure may be introduced into the modified conjugated diene copolymer by adding a terminal modifier containing an onium generator to perform a reaction. In addition, a terminal-modifying agent having a plurality of functional groups containing these elements in a molecule, or a terminal-modifying agent having a plurality of functional groups containing these elements may be used. When these terminal modifiers are continuously added to a molded article such as a vehicle tire, for example, a vulcanized rubber composition having a smaller rolling resistance, excellent wear resistance, and excellent tensile strength and tear strength tends to be obtained.

Hereinafter, various terminal modifiers usable in the present invention will be described. However, the terminal modifier is not limited to the exemplified ones.

Examples of the nitrogen-containing compound as the terminal modifier include: isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, carbonyl compounds containing a nitrogen group, vinyl compounds containing a nitrogen group, epoxy compounds containing a nitrogen group, and the like.

Examples of the silicon-containing compound as the terminal modifier include: halogenated silicon compounds, epoxidized silicon compounds, vinylated silicon compounds, silicon alkoxide compounds containing nitrogen-containing groups, and the like.

Examples of the tin-containing compound as the terminal modifier include: tin halide compounds, organotin carboxylate compounds, and the like. Examples of the phosphorus-containing compound as the terminal modifier include: phosphite compounds, phosphine compounds, and the like. Examples of the oxygen-containing compound as the terminal modifier include: epoxy compounds, ether compounds, ester compounds, and the like. Examples of the sulfur-containing compound as the terminal modifier include: mercapto derivatives, thiocarbonyl compounds, isothiocyanates, and the like. Examples of the halogen-containing compound as the terminal modifier include the above-mentioned silicon halide compound and tin halide compound.

Examples of the onium salt-forming agent as the terminal modifier include protected amine compounds (ammonium salts) which can form primary amines or secondary amines; protected phosphine compounds (phosphonium-forming) which form phosphine hydrides; the compound capable of forming a hydroxyl group or a thiol (produced hydrocarbon or sulfonium), etc., is preferably a terminal modifier having a functional group for bonding the onium generator to the modified conjugated diene polymer in each molecule. Examples of the functional group to be bonded to the modified conjugated diene polymer include carbonyl groups (such as ketones and esters), unsaturated groups such as vinyl groups, epoxy groups, silicon halide groups, and silicon alkoxide groups.

Specific examples of the terminal modifier include, as the isocyanate compound: 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate (raw 4, 4-diphenylmethanediisocyanate, CMDI), phenylisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, butyl isocyanate, 1,3, 5-benzene triisocyanate, and the like. Examples of the isocyanuric acid derivative include: 1,3, 5-tris (3-trimethoxysilylpropyl) isocyanurate, 1,3, 5-tris (3-triethoxysilylpropyl) isocyanurate, 1,3, 5-tris (oxetan-2-yl) -1,3, 5-triazinan-2, 4, 6-trione, 1,3, 5-tris (isothiocyanatomethyl) -1,3, 5-triazinan-2, 4, 6-trione, 1,3, 5-trivinyl-1, 3, 5-triazinan-2, 4, 6-trione and the like.

Specific examples of the carbonyl compound having a nitrogen group include: 1, 3-dimethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 1-methyl-3- (2-methoxyethyl) -2-imidazolidinone, N-methyl-2-pyrrolidone, N-methyl-2-piperidone, N-methyl-2-quinolone, 4 '-bis (diethylamino) benzophenone, 4' -bis (dimethylamino) benzophenone, methyl-2-pyridinone, methyl-4-pyridinone, propyl-2-pyridinone, di-4-pyridinone, 2-benzoylpyridine, N, N, N ', N' -tetramethylurea, N-methyl-2-imidazolidinone, N-methyl-2-quinolone, 4 '-bis (diethylamino) benzophenone, 4' -bis (dimethylamino) benzophenone, methyl-2-, N, N-dimethyl-N ', N' -diphenylurea, N-diethylcarbamic acid methyl ester, N-diethylacetamide, N-dimethyl-N ', N' -dimethylaminoacetamide, N-dimethylpicolinic acid amide, N-dimethylisonicotinic acid amide, and the like.

Specific examples of the nitrogen group-containing vinyl compound include: n, N-dimethylacrylamide, N-dimethylmethacrylamide, N-methylmaleimide, N-methylphthalimide, N-bistrimethylsilylacrylamide, morpholinoacrylamide, 3- (2-dimethylaminoethyl) styrene, (dimethylamino) dimethyl-4-vinylphenylsilane, 4 '-vinylenebis (N, N-dimethylaniline), 4' -vinylenebis (N, N-diethylaniline), 1-bis (4-morpholinophenyl) ethylene, 1-phenyl-1- (4-N, N-dimethylaminophenyl) ethylene and the like.

Specific examples of the epoxy compound containing a nitrogen group include: n, N, N ', N ' -tetraglycidyl-1, 3-bisaminomethylcyclohexane, N, N, N ', N ' -tetraglycidyl-m-xylenediamine, 4-methylene-bis (N, N-diglycidylaniline), 1, 4-bis (N, N-diglycidylamino) cyclohexane, N, N, N ', N ' -tetraglycidyl-p-phenylenediamine, 4' -bis (diglycidylamino) benzophenone, 4- (4-glycidylpiperazinyl) - (N, N-diglycidylaniline), 2- [2- (N, N-diglycidylamino) ethyl ] -1-glycidylpyrrolidine, bis (glycidylmethylaniline), N, N ' -diglycidyl-4-glycidyloxyaniline, 4' -diglycidyl-diphenylmethylamine, 4' -diglycidyl-dibenzylmethylamine, N-diglycidyl aniline, N-diglycidyl o-toluidine, N-diglycidyl aminomethylcyclohexane, and the like.

Specific examples of the halogenated silicon compound include: dibutyldichlorosilane, methyltrichlorosilane, dimethyldichlorosilane, methyldichlorosilane, trimethylchlorosilane, tetrachlorosilane, tris (trimethylsiloxy) chlorosilane, tris (dimethylamino) chlorosilane, hexachlorodisilane, bis (trichlorosilane) methane, 1, 2-bis (trichlorosilane) ethane, 1, 2-bis (methyldichlorosilyl) ethane, 1, 4-bis (trichlorosilane) butane, 1, 4-bis (methyldichlorosilyl) butane, and the like.

Specific examples of the epoxy silicon compound include: 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, epoxy-modified silicone and the like.

Specific examples of the silicon alkoxide compound include: tetramethoxysilane, tetraethoxysilane, triphenoxymethylsilane, methoxy-substituted polyorganosiloxane, and the like.

Specific examples of the silicon alkoxide compound containing a nitrogen-containing group include: 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyltriethoxysilane, 3-morpholinopropyltrimethoxysilane, 3-piperidinylpropyltriethoxysilane, 3-hexamethyleneiminopropylmethyldiethoxysilane, 3- (4-methyl-1-piperazinyl) propyltriethoxysilane, 1- [3- (triethoxysilyl) -propyl ] -3-methylhexahydropyrimidine, 3- (4-trimethylsilyl-1-piperazinyl) propyltriethoxysilane, 3- (3-triethylsilyl-1-imidazolidinyl) propylmethyldiethoxysilane, 3- (3-trimethylsilyl-1-hexahydropyrimidyl) propyltrimethoxysilane, 3-dimethylamino-2- (dimethylaminomethyl) propyltrimethoxysilane, bis (3-dimethoxymethylsilylpropyl) -N-methylamine, bis (3-trimethoxysilylpropyl) -N-methylamine, bis (3-triethoxysilylpropyl) methylamine, tris (trimethoxysilyl) amine, tris (3-trimethoxysilylpropyl) amine, N, N, N ', N' -tetrakis (3-trimethoxysilylpropyl) ethylenediamine, 3-isothiocyanatopropyltrimethoxysilane, 3-cyanopropyltrimethoxysilane, 2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclopentane, methyl methacrylate, ethyl methacrylate, 2, 2-diethoxy-1- (3-triethoxysilylpropyl) -1-aza-2-silacyclopentane, 2-dimethoxy-1- (4-trimethoxysilylbutyl) -1-aza-2-silacyclohexane, 2-dimethoxy-1- (3-dimethoxymethylsilylpropyl) -1-aza-2-silacyclopentane, 2-dimethoxy-1-phenyl-1-aza-2-silacyclopentane, 2-diethoxy-1-butyl-1-aza-2-silacyclopentane, 2-dimethoxy-1-methyl-1-aza-2-silacyclopentane, 2-diethoxy-1-aza-2-silacyclopentane, 2-dimethoxy-1-methyl-1-aza-2-silacyclopentane, 2-methoxy-1-methyl-1-aza-2-, 2, 2-dimethoxy-8- (4-methylpiperazino) methyl-1, 6-dioxa-2-silacyclooctane, 2-dimethoxy-8- (N, N-diethylamino) methyl-1, 6-dioxa-2-silacyclooctane and the like.

Among the protected amine compounds which can form a primary amine or a secondary amine, specific examples of the compound having an unsaturated bond and a protected amine in the molecule include: 4,4 '-ethenylbis [ N, N-bis (trimethylsilyl) aniline ], 4' -ethenylbis [ N, N-bis (triethylsilyl) aniline ], 4 '-ethenylbis [ N, N-bis (t-butyldimethylsilyl) aniline ], 4' -ethenylbis [ N-methyl-N- (trimethylsilyl) aniline ], 4 '-ethenylbis [ N-ethyl-N- (trimethylsilyl) aniline ], 4' -ethenylbis [ N-methyl-N- (triethylsilyl) aniline ], 4 '-ethenylbis [ N-ethyl-N- (triethylsilyl) aniline ], 4' -ethenylbis [ N-methyl-N- (t-butyldimethylsilyl) benzene ] or a mixture thereof Amine ], 4' -vinylidenebis [ N-ethyl-N- (tert-butyldimethylsilyl) aniline ], 1- [ 4-N, N-bis (trimethylsilyl) aminophenyl ] -1- [ 4-N-methyl-N- (trimethylsilyl) aminophenyl ] ethylene, 1- [ 4-N, N-bis (trimethylsilyl) aminophenyl ] -1- [ 4-N, N-dimethylaminophenyl ] ethylene and the like.

Among the protected amine compounds which can form a primary amine or a secondary amine, specific examples of the compound having an alkoxysilane and a protected amine in the molecule include: n, N-bis (trimethylsilyl) aminopropyltrimethoxysilane, N-bis (trimethylsilyl) aminopropylmethyldimethoxysilane, N-bis (trimethylsilyl) aminopropyltriethoxysilane, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane, N-bis (trimethylsilyl) aminoethyltrimethoxysilane, N-bis (trimethylsilyl) aminoethylmethyldiethoxysilane, N-bis (triethylsilyl) aminopropylmethyldiethoxysilane, 3- (4-trimethylsilyl-1-piperazinyl) propyltriethoxysilane, 3- (3-triethylsilyl-1-imidazolidinyl) propylmethyldiethoxysilane, N-bis (trimethylsilyl) aminopropylmethyldimethoxysilane, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane, 3- (4-trimethylsilyl-1-piperazinyl) propyltriethoxysilane, 3- (3-trimethylsilyl-1-hexahydropyrimidyl) propyltrimethoxysilane, 2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclopentane, 2-diethoxy-1- (3-triethoxysilylpropyl) -1-aza-2-silacyclopentane, 2-dimethoxy-1- (4-trimethoxysilylbutyl) -1-aza-2-silacyclohexane, 2-dimethoxy-1- (3-dimethoxymethylsilylpropyl) -1-aza-2-silacyclopentane, 2, 2-dimethoxy-1-phenyl-1-aza-2-silacyclopentane, 2-diethoxy-1-butyl-1-aza-2-silacyclopentane, 2-dimethoxy-1-methyl-1-aza-2-silacyclopentane, and the like.

Specific examples of the tin halide compound include: tetrachlorotin, tetrabromotin, trichlorobutyltin, trichlorooctyltin, dibromodimethyltin, dibutyltin dichloride, chlorotrimethyltin, chlorotriectyltin, chlorotriphenyltin, 1, 2-bis (trichlorostannyl) ethane, 1, 2-bis (methyldichlorstannyl) ethane, 1, 4-bis (trichlorostannyl) butane, 1, 4-bis (methyldichlorstannyl) butane and the like.

Specific examples of the organotin carboxylate compounds include: ethyl tin tristearate, butyl tin tricaprylate, butyl tin tristearate, butyl tin trilaurate, dibutyl tin dicaprylate, and the like.

Specific examples of the phosphite ester compound include: trimethyl phosphite, tributyl phosphite, triphenyl phosphite oxide, and the like.

Specific examples of the phosphine compound include: a protected phosphine compound such as P, P-bis (trimethylsilyl) phosphinyl trimethoxysilane or P, P-bis (triethylsilyl) phosphinyl methylethoxysilane, 3-dimethylphosphinyl trimethoxysilane or 3-diphenylphosphinyl propyltrimethoxysilane.

Specific examples of the oxygen-containing compound include: polyglycidyl ethers such as ethylene glycol diglycidyl ether and glycerol triglycidyl ether; polyepoxy compounds such as 1, 4-diglycidylbenzene, 1,3, 5-triglycidylbenzene, poly-epoxidized liquid polybutadiene, epoxidized soybean oil, epoxidized linseed oil and the like; ester compounds such as dimethyl adipate, diethyl adipate, dimethyl terephthalate and diethyl terephthalate, which generate hydroxyl groups at the polymer terminals.

Specific examples of the sulfur-containing compound include protected thiol compounds such as S-trimethylsilylthiopropyltrimethoxysilane and S-triethylsilylthiopropylmethyldiethylsilane, S-methylthiopropyltrimethoxysilane, S-ethylthiopropylmethyldiethoxysilane, N-diethyldithiocarbamate, phenylisothiocyanate, phenyl-1, 4-diisothiocyanate, hexamethylene diisothiocyanate and butyl isothiocyanate.

The amount of the terminal modifier used is preferably more than 0.5 equivalent to 10 equivalents, more preferably more than 0.7 equivalent to 5 equivalents, and still more preferably more than 1 equivalent to 4 equivalents, relative to 1 equivalent of the active terminal of the conjugated diene copolymer. In the present embodiment, the amount of the active end of the conjugated diene polymer can be calculated from the amount of the organolithium compound used in the polymerization and the number of lithium atoms bonded to the organolithium compound, and can also be calculated from the number average molecular weight of the obtained conjugated diene copolymer.

The terminal modifier may be used alone or in combination of two or more.

The weight average molecular weight (in terms of polystyrene) of the conjugated diene copolymer of the present invention is preferably 10 to 200 ten thousand, and more preferably 15 to 100 ten thousand, in view of processability and physical properties. The weight average molecular weight can be determined from a calibration curve using standard polystyrene by measuring a chromatogram by using a Gel Permeation Chromatograph (GPC) using a column using a polystyrene gel as a filler.

In the case where the aromatic vinyl compound (C) is not used, the ratio of the polyfunctional vinyl aromatic copolymer (a) to the conjugated diene compound (B) is preferably in the following range.

The content of the structural unit (A1) derived from the polyfunctional vinyl aromatic copolymer (A) is 0.001 to 6% by weight, preferably 0.001 to 5% by weight, more preferably 0.005 to 5% by weight, still more preferably 0.01 to 5% by weight, and the content of the structural unit (B1) derived from the conjugated diene compound (B) is 29 to 99.999% by weight, preferably 80 to 99.999% by weight, more preferably 90 to 99.995% by weight, still more preferably 95 to 99.99% by weight.

When the aromatic vinyl compound (C) is used, the ratio is preferably in the following range. The structural unit (a1) is in the same range as described above, and the structural unit (B1) is 30 to 97.999 wt%, preferably 45 to 94.995 wt%, and more preferably 55 to 89.99 wt%. The structural unit (C1) derived from the aromatic vinyl compound (C) is 2 to 50% by weight, preferably 5 to 45% by weight, and more preferably 10 to 40% by weight.

In the case of the modified conjugated diene copolymer, the structural unit (H1) derived from the terminal modifier may be 1 to 0% by weight. When the structural element (H1) is included, the structural element (H1) is regarded as an outer number and is not included in the calculation of the ratio.

The structural unit (a1) imparts a branched structure to the conjugated diene copolymer to increase the molecular weight and/or increase the amount of the terminal modifier introduced, thereby improving the physical properties of the conjugated diene copolymer and/or improving the dispersibility of the reinforcing filler.

The microstructure (cis bond, trans bond, vinyl bond amount) of the conjugated diene copolymer can be arbitrarily changed by using a polar compound or the like, but in a state before the terminal is modified, the vinyl bond (1,2 bond) is preferably contained in an amount of 10 to 80 mol% in the conjugated diene unit. When the conjugated diene copolymer of the present invention is used as an automobile tire by preparing a conjugated diene copolymer composition described later and crosslinking the conjugated diene copolymer, the content is preferably 20 to 75 mol%, more preferably 30 to 75 mol%, and still more preferably 40 to 70 mol% in order to balance the rolling resistance performance and the wear resistance to a high degree. In this case, the mass ratio of the cis bond to the trans bond in the conjugated diene bonding unit is preferably 1/1.1 to 1.5.

A reaction terminator may be added to the polymer solution of the conjugated diene copolymer obtained by the above polymerization method, if necessary. Examples of the reaction terminator include alcohols such as methanol, ethanol, and propanol; organic acids such as stearic acid, lauric acid, and caprylic acid; water, and the like.

After the polymerization reaction of the conjugated diene copolymer is carried out, the metal species contained in the polymer may be ashed as necessary. As a method of removing ash, for example, a method of contacting water, an oxidizing agent such as an organic acid, an inorganic acid, or hydrogen peroxide with a polymer solution to extract metals and then separating a water layer is used.

Further, an antioxidant may be added to the polymer solution of the conjugated diene copolymer. Examples of the antioxidant include a phenol stabilizer, a phosphorus stabilizer, and a sulfur stabilizer.

As a method for obtaining a conjugated diene copolymer from a polymer solution, a conventional method can be applied. For example, it is applicable: a method in which the polymer is obtained by separating the solvent by steam stripping or the like, then filtering and separating the polymer, and further dehydrating and drying the polymer; a method of concentrating with a flash tank (flash tank) and then devolatilizing with a puffer extruder or the like; and a method of directly performing devolatilization using a drum dryer (dry dryer), etc.

The conjugated diene copolymer composition of the present invention preferably contains 0.5 to 200 parts by mass of at least one reinforcing filler selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides, and carbon black, per 100 parts by mass of the conjugated diene copolymer.

The silica-based inorganic filler contained in the conjugated diene copolymer composition is preferably solid particles containing SiO2 or a silicate as a main component of a constituent unit. The main component herein means a component accounting for 50 mass% or more, preferably 70 mass% or more, and more preferably 90 mass% or more of the whole.

Specific examples of the silica-based inorganic filler include: inorganic fibrous materials such as silica, clay (clay), talc (talc), mica (mica), diatomaceous earth, wollastonite (wollastonite), montmorillonite (montmorillonite), zeolite (zeolite), and glass fiber. The silica-based inorganic filler may be used alone or in combination of two or more. In addition, a silica-based inorganic filler having a surface hydrophobized, and a mixture of a silica-based inorganic filler and an inorganic filler other than silica-based inorganic filler may also be used. Of these, silica and glass fiber are preferable, and silica is more preferable.

As the silica, dry silica, wet silica, synthetic silicate silica and the like can be used, and among these, wet silica is preferable in terms of more excellent balance between improvement of fracture characteristics and wet skid resistance (wet resistance).

From the viewpoint of obtaining good abrasion resistance and fracture characteristics, the nitrogen adsorption specific surface area of the silica-based inorganic filler determined by the Brunauer-Emmett-Teller (BET) adsorption method is preferably 170m²/g～300m²(ii) g, more preferably 200m²/g～300m²/g。

The amount of the silica-based inorganic filler blended in the conjugated diene-based copolymer composition is preferably 0.5 to 200 parts by mass per 100 parts by mass of the conjugated diene-based copolymer. The upper limit of the amount of the silica-based inorganic filler to be blended is preferably 100 parts by mass or less, and more preferably 75 parts by mass or less, per 100 parts by mass of the conjugated diene-based copolymer as the rubber component. The lower limit is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, and particularly preferably 35 parts by mass or more. When the amount of the silica-based inorganic filler is within the above range, the effect of adding the filler is exhibited, and the dispersibility of the silica-based inorganic filler becomes good, so that the processability of the obtained composition is improved and the mechanical strength is improved.

Carbon black may be added to the conjugated diene copolymer composition as a reinforcing filler other than the silica inorganic filler.

Examples of the carbon black include various types of carbon black such as semi-reinforcing furnace (SRF), Fast Extrusion Furnace (FEF), High Abrasion Furnace (HAF), medium abrasion furnace (ISAF), and Super Abrasion Furnace (SAF). From the viewpoint of excellent reinforcing effect, nitrogen gettering is preferableThe specific surface area is 50m²(ii) carbon black having a dibutyl phthalate (DBP) oil absorption of 80mL/100g or more.

The amount of carbon black blended is 0.5 to 200 parts by mass, preferably 3 to 100 parts by mass, and more preferably 5 to 50 parts by mass, per 100 parts by mass of the conjugated diene copolymer.

The conjugated diene copolymer composition may contain not only a silica-based inorganic filler or carbon black but also a metal oxide or metal hydroxide as a reinforcing filler. The metal oxide is preferably a solid particle having a main component of the chemical formula MxOy (M represents a metal atom, and x and y each represent an integer of 1 to 6). The main component herein means a component accounting for 50 mass% or more, preferably 70 mass% or more, and more preferably 90 mass% or more of the whole.

As the metal oxide, for example, alumina, titania, magnesia, zinc oxide, or the like can be used. Examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide. One kind of the metal oxide and the metal hydroxide may be used alone, or two or more kinds thereof may be used in combination. In addition, a mixture with an inorganic filler other than metal oxides and metal hydroxides may also be used.

The conjugated diene copolymer composition may contain a silane coupling agent. The silane coupling agent has a function of causing the conjugated diene copolymer (silica-based inorganic filler to interact with each other tightly, and has groups having affinity or bondability with the conjugated diene copolymer and the silica-based inorganic filler, respectively.

Specific examples of the silane coupling agent include: bis- [3- (triethoxysilyl) -propyl ] -tetrasulfide, bis- [3- (triethoxysilyl) -propyl ] -disulfide, bis- [2- (triethoxysilyl) -ethyl ] -tetrasulfide, and the like.

The amount of the silane coupling agent to be blended is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and still more preferably 1 to 15 parts by mass, per 100 parts by mass of the silica-based inorganic filler. By setting the amount of the silane coupling agent to the above numerical range, a sufficient blending effect can be obtained and the economy can be improved.

The conjugated diene copolymer composition can be produced by mixing the above components.

The method of mixing the conjugated diene copolymer with at least one reinforcing filler selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides, and carbon black, and a silane coupling agent as desired is not particularly limited. Examples thereof include: a melt-kneading method using a general mixer such as an open roll, a Banbury mixer, a kneader, a single-screw extruder, a twin-screw extruder, or a multi-screw extruder; and a method of melting and mixing the respective components and then heating to remove the solvent. Among these, from the viewpoint of productivity and good kneading properties, a melt kneading method using a roll, an internal mixer, a kneader, or an extruder is preferable. Further, any of a method of kneading the rubber component and various compounding agents at once and a method of mixing them in a plurality of times can be applied.

In the present invention, the degree of the polymer-concentrating ability on the surface of the filler can be represented by the amount of bound rubber (bound rubber) of the modified conjugated diene polymer at 25 ℃. From the viewpoint of improving the wear resistance and the breaking strength, the amount of the conjugated diene copolymer composition (rubber composition) after completion of the kneading is preferably 15% by mass or more, more preferably 20% by mass or more, and still more preferably 30% by mass or more.

The amount of the bound rubber can be measured by the method described in examples described later.

The conjugated diene copolymer composition may be a vulcanized composition obtained by vulcanizing the conjugated diene copolymer composition with a vulcanizing agent. Examples of the vulcanizing agent include radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds. The sulfur compound includes sulfur monochloride, sulfur dichloride, disulfide compounds, polymer polysulfide compounds, and the like.

The amount of the vulcanizing agent to be used is not particularly limited, and is preferably 0.01 to 20 parts by mass, and more preferably 0.1 to 15 parts by mass, based on 100 parts by mass of the conjugated diene copolymer. As the vulcanization method, conventional methods can be applied, and the vulcanization temperature is, for example, preferably 120 to 200 ℃ and more preferably 140 to 180 ℃.

In vulcanization, a vulcanization accelerator may be used as necessary. The vulcanization accelerator may be a conventionally used material, and examples thereof include sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators. As the vulcanization aid, zinc white, stearic acid, or the like can be used.

The amount of the vulcanization accelerator to be used is not particularly limited, and is preferably 0.01 to 20 parts by mass, and more preferably 0.1 to 15 parts by mass, based on 100 parts by mass of the conjugated diene copolymer.

In the conjugated diene copolymer composition of the present invention, a softening agent for rubber may be blended in order to improve processability. The softener for rubber is preferably mineral oil or a liquid or low molecular weight synthetic softener.

The softening agent for mineral oil rubber, which is called process oil or extender oil (process oil) and is used for softening, compatibilization and improvement of processability of rubber, is a mixture of an aromatic ring, a naphthenic ring and a paraffin chain, and is called a paraffinic system in which 50% or more of all carbons in the paraffin chain, a naphthenic system in which 30% to 45% of carbons in the naphthenic ring, and an aromatic system in which more than 30% of carbons in the aromatic ring are contained. The softening agent for rubber used in the present embodiment is preferably a naphthenic and/or paraffinic softening agent for rubber.

The amount of the rubber softener to be blended is not particularly limited, and is preferably 10 to 80 parts by mass, and more preferably 20 to 50 parts by mass, per 100 parts by mass of the conjugated diene copolymer.

In the conjugated diene copolymer composition, various additives other than the above-described softening agent or filler, heat-resistant stabilizer, antistatic agent, weather-resistant stabilizer, aging inhibitor, colorant, lubricant, and the like may be used within a range not to impair the object of the present embodiment. Specific examples of the filler include calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate.

Examples of the softener to be blended as needed for adjusting the hardness or fluidity of the target product include liquid paraffin, castor oil, linseed oil, and the like. As a heat stabilizer, an antistatic agent, a weather stabilizer, an antiaging agent, a colorant and a lubricant, conventional materials can be used.

The rubber crosslinked material of the present invention is obtained by crosslinking the rubber composition. For example, in the case of a tire, the rubber composition is extruded and molded in accordance with the shape of the tire (specifically, the shape of the tread), and the rubber composition is heated and pressurized in a vulcanizer to manufacture the tread, and the tread and other components are assembled to manufacture a target tire.

The conjugated diene copolymer composition (rubber composition) of the present invention is excellent in mechanical strength and abrasion resistance when the rubber crosslinked material is produced. Therefore, as described above, the present invention can be suitably applied to tire members such as treads and casing side members of tires such as low fuel consumption tires, large tires, and high performance tires. Further, the present invention can be suitably applied not only to the tire member but also to a rubber belt, a rubber hose, a footwear material, and the like.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, the parts are all parts by weight unless otherwise specified, and the physical properties are evaluated by the following methods.

1) Molecular weight and molecular weight distribution

The molecular weight and molecular weight distribution were measured using GPC (HLC-8220 GPC, manufactured by Tosoh) using Tetrahydrofuran (THF) as a solvent, using a calibration curve prepared from monodisperse polystyrene at a flow rate of 1.0 ml/min, a column temperature of 38 ℃ and a column temperature.

2) Structure of multifunctional vinyl aromatic copolymer

JNM-LA600 type nuclear magnetic resonance spectroscopy apparatus manufactured by using Japan Electron, by¹³C-Nuclear Magnetic Resonance (NMR) and¹H-NMR analysis. Using chloroform-d₁As solvent, and the resonance line of tetramethylsilane was used as internal standard.

3) Munich viscosity (Mooney viscocity) (ML (1+4)100 ℃ C.)

The temperature was determined in accordance with Japanese Industrial Standards (JIS) K6300-1 using an L-shaped rotor, preheating for 1 minute, a rotor operating time of 4 minutes, and a temperature of 100 ℃.

4) Confirmation of microgel (haze)

A sample obtained by dissolving 0.5g of the copolymer rubber in 100g of toluene was placed in a quartz cell, and the haze (haze) was measured using an integrating sphere type light transmittance measuring apparatus (SZ- Σ 90, manufactured by japan electric color corporation) using toluene as a reference sample.

Setting the haze value below 0.5 as no microgel: when the haze value exceeds 0.5, the microgel is observed: x.

5) Glass transition temperature (Tg)

The glass substrate was uniformly coated with a solution of the polyfunctional vinyl aromatic copolymer dissolved in toluene so that the thickness after drying became 20 μm, and dried by heating for 30 minutes at 90 minutes using a hot plate. The glass substrate and the obtained resin film were placed in a Thermomechanical Analyzer (TMA) (Thermomechanical Analyzer), and heated at a temperature rise rate of 10 ℃/min to 220 ℃ under a nitrogen gas flow, and further subjected to a heat treatment at 220 ℃ for 20 minutes, thereby removing the residual solvent and curing the polyfunctional vinyl aromatic copolymer. After the glass substrate was left to cool to room temperature, the sample in the TMA measuring apparatus was brought into contact with the analysis probe, and scanning measurement was performed from 30 ℃ to 360 ℃ at a temperature increase rate of 10 ℃/min under a nitrogen gas flow, and the softening temperature was determined by the tangent method.

6) Content of vinyl bond of conjugated diene unit

A sample was prepared as a carbon disulfide solution, an infrared spectrum was measured in a range of 600cm-1 to 1000cm-1 using a solution tank, and the vinyl bond amount was determined by using the absorbance at a predetermined wave number according to the calculation formula of the method of Hampton (styrene-butadiene copolymer). The Spectrum (Spectrum)100 manufactured by platinum Elmer (Parkin Elmer) was used as the apparatus.

7) Amount of bound rubber (%)

Using an internal kneading apparatus having a kneading chamber volume of 2 liters, 100 parts by mass of a modified conjugated diene polymer and 60 parts by mass of wet silica (BET specific surface area: 205. + -. 10 m) were mixed in an amount of 60% (volume of rubber composition to be kneaded/volume in kneading chamber). times.100) } of²(g), manufactured by Tosoh Silica (Tosoh Silica) Co., Ltd., trade name "Nippon (Nipsil) AQ"), was kneaded, and the kneaded rubber was discharged when the highest kneading temperature of 160 ℃ was reached, to obtain a rubber composition M for measuring a bound rubber amount.

0.2g of the rubber composition M was cut into 1mm square and measured for mass, then added to 25mL of toluene, left at 25 ℃ for 48 hours, filtered through a glass fiber filter manufactured by Edwardsiec (ADVANTEC) to separate the toluene-insoluble component, and the separated toluene-insoluble component was dried under vacuum at 25 ℃ and weighed, and the amount of the bound rubber was determined by the following formula.

The bound rubber amount (%) { (mass of toluene-insoluble matter-mass of wet silica in rubber composition M)/(mass of rubber composition M-mass of wet silica in rubber composition M) } × 100

Further, the BET specific surface area of silica is measured according to International Organization for Standardization (ISO) 5794/1.

8) Tensile strength

The 300% modulus (modulis) was measured by the tensile test method of JIS K6251.

In the first invention, the measurement value of the crosslinked rubber obtained in comparative example 1 was indexed with 100.

In the second invention, the measurement value of the crosslinked rubber obtained in example 20B was indexed with 100.

In the third invention, the measurement value of the crosslinked rubber obtained in example 10C was indexed with 100.

The larger index value indicates more excellent tensile strength.

9) Wear resistance

The abrasion loss at a slip ratio of 30% was measured by a method using a lambouren type abrasion tester in accordance with JIS K6264.

In the first invention, the measurement value of the crosslinked rubber obtained in comparative example 1 was indexed with 100.

In the second invention, the measurement value of the crosslinked rubber obtained in example 20 was indexed with 100.

In the third invention, the measurement value of the crosslinked rubber obtained in example 10 was indexed with 100.

The larger the index value, the better the abrasion resistance.

10) Solubility in solvents

The copolymer was soluble in toluene, xylene, THF, dichloroethane, dichloromethane, and chloroform, and the case where the copolymer was dissolved in 100g or more of each of the above solvents and no gel was observed was defined as solvent solubility.

The raw materials used in the examples or their abbreviations are as follows.

DVB-630: a mixture of a divinylbenzene component and an ethylvinylbenzene component; divinylbenzene content 63.0 wt%, manufactured by NIPPON STEEL Chemical & Material)

Indene: heguang pure drug preparation

Bht (butylated hydroxytoluene): 2, 6-di-tert-butyl-p-cresol

BTESPA: bis (3-trimethoxysilylpropyl) methylamine

< embodiment of the first invention >

Example 1A

92.98g of DVB-630 (divinylbenzene content: 0.45 mol, ethylvinylbenzene content: 0.26 mol), 276.58g (2.29 mol) of indene and 1.50 mol (172.5mL) of n-propyl acetate were charged into a 1.0L reactor, and 60 mmol of boron trifluoride diethyl ether complex (7.5mL) was added thereto at 70 ℃ to carry out a reaction for 2.5 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, and devolatilized under reduced pressure at 60 ℃ to recover a copolymer. The obtained copolymer was weighed, and it was confirmed that 221.7g of the copolymer 1A was obtained.

In examples and comparative examples, the obtained copolymers were soluble polyfunctional vinyl aromatic copolymers.

The obtained polyfunctional vinyl aromatic copolymer 1A had Mn of 828, Mw of 2620 and Mw/Mn of 3.17. By performing 13C-NMR and 1H-NMR analyses, the polyfunctional vinyl aromatic copolymer 1A contained 13.8 mol% (15.1 wt%) of a structural unit derived from divinylbenzene, 7.9 mol% (8.8 wt%) in total of a structural unit derived from ethylvinylbenzene, and 78.2 mol% (76.1 wt%) of a structural unit derived from indene. The structural unit derived from divinylbenzene having residual vinyl groups (corresponding to the structural unit (a1)) contained in the polyfunctional vinyl aromatic copolymer 1A was 11.0 mol% (12.1 wt%).

Further, the result of TMA measurement of the cured product is Tg: 182 ℃ and the softening temperature is above 280 ℃. The weight loss at 350 ℃ was 1.52% by weight as determined by thermogravimetric analysis (TGA). On the other hand, the compatibility with the epoxy resin was good.

The polyfunctional vinyl aromatic copolymer 1A was solvent-soluble.

Example 2A

187.11g of DVB-630 (divinylbenzene content: 0.90 mol, ethylvinylbenzene content: 0.53 mol), 182.37g (1.57 mol) of indene and 1.50 mol (172.5mL) of n-propyl acetate were charged into a 1.0L reactor, and 40 mmol of boron trifluoride diethyl ether complex (5.0mL) was added thereto at 70 ℃ to carry out a reaction for 3.5 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and reprecipitated, filtered and dried under strong stirring using 4,500mL of methanol, thereby recovering the polyfunctional vinyl aromatic copolymer. The obtained polyfunctional vinyl aromatic copolymer was weighed, and it was confirmed that 238.7g of the polyfunctional vinyl aromatic copolymer 2A was obtained.

The obtained polyfunctional vinyl aromatic copolymer 2A had Mn of 1240, Mw of 3580 and Mw/Mn of 2.89. In copolymer 2A, 29.6 mol% (31.3 wt%) of a structural unit derived from divinylbenzene, a total of 17.9 mol% (19.2 wt%) of a structural unit derived from ethylvinylbenzene, and 52.5 mol% (49.5 wt%) of a structural unit derived from indene were contained. The content of the structural unit derived from divinylbenzene having a residual vinyl group contained in the polyfunctional vinyl aromatic copolymer 2A was 19.5 mol% (20.6 wt%).

The cured product had a Tg of 205 ℃ and a softening temperature of 280 ℃ or higher. The weight loss at 350 ℃ was 0.96% by weight as determined by thermogravimetric analysis (TGA). On the other hand, the compatibility with the epoxy resin was ≈ o.

The polyfunctional vinyl aromatic copolymer 2A was solvent-soluble.

Example 3A

31.16g of DVB-630 (divinylbenzene content: 0.15 mol, ethylvinylbenzene content: 0.09 mol), 320.83g (2.76 mol) of indene and 1.50 mol (172.5mL) of n-propyl acetate were charged into a 1.0L reactor, and 80 mmol of boron trifluoride diethyl ether complex (10.0mL) was added thereto at 70 ℃ to carry out a reaction for 3.0 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and reprecipitated, filtered and dried under strong stirring using 4,500mL of methanol, thereby recovering the polyfunctional vinyl aromatic copolymer. The obtained polyfunctional vinyl aromatic copolymer was weighed, and it was confirmed that 256.3g of the polyfunctional vinyl aromatic copolymer 3A was obtained.

The obtained polyfunctional vinyl aromatic copolymer 3A had Mn of 659, Mw of 2560 and Mw/Mn of 3.88. In the copolymer 3A, 5.1 mol% (5.8 wt%) of a structural unit derived from divinylbenzene, 2.9 mol% (3.3 wt%) in total of a structural unit derived from ethylvinylbenzene, and 92.0 mol% (90.9 wt%) of a structural unit derived from indene were contained. The content of the structural unit derived from divinylbenzene having a residual vinyl group contained in the polyfunctional vinyl aromatic copolymer 3A was 3.3 mol% (3.8 wt%).

The cured product had a Tg of 192 ℃ and a softening temperature of 280 ℃ or higher. The weight loss at 350 ℃ was 1.63% by weight as determined by TGA. On the other hand, the compatibility with the epoxy resin was ≈ o.

The polyfunctional vinyl aromatic copolymer 3A was solvent-soluble.

Comparative example 1A

249.41g of DVB-630 (divinylbenzene content: 1.20 mol, ethylvinylbenzene content: 0.70 mol), 127.20g (1.10 mol) of indene and 1.50 mol (172.5mL) of n-propyl acetate were charged into a 1.0L reactor, and 40 mmol of boron trifluoride diethyl ether complex (5.0mL) was added thereto at 70 ℃ to carry out a reaction for 3.0 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and reprecipitated, filtered and dried under strong stirring using 4,500mL of methanol, thereby recovering the polyfunctional vinyl aromatic copolymer. The obtained polyfunctional vinyl aromatic copolymer was weighed, and it was confirmed that 253.6g of a polyfunctional vinyl aromatic copolymer C1A was obtained.

The obtained polyfunctional vinyl aromatic copolymer C1A had Mn of 1430, Mw of 5030 and Mw/Mn of 3.52. Copolymer C1A contained 40.2 mol% (41.6 wt%) of structural units derived from divinylbenzene, a total of 23.6 mol% (25.0 wt%) of structural units derived from ethylvinylbenzene, and 36.2 mol% (33.4 wt%) of structural units derived from indene. The content of the structural unit derived from divinylbenzene having a residual vinyl group contained in the polyfunctional vinyl aromatic copolymer C1A was 26.5 mol% (27.4 wt%).

The cured product has a Tg of 168 ℃ and a softening temperature of 280 ℃ or higher. The weight loss at 350 ℃ was 2.13% by weight as determined by TGA. On the other hand, the compatibility with the epoxy resin was ≈ o.

The polyfunctional vinyl aromatic copolymer C1A was found to be solvent-soluble.

Comparative example 2A

12.46g of DVB-630 (divinylbenzene content: 0.06 mol, ethylvinylbenzene content: 0.04 mol), 337.44g (2.90 mol) of indene and 1.50 mol (172.5mL) of n-propyl acetate were charged into a 1.0L reactor, and 80 mmol of boron trifluoride diethyl ether complex (10.0mL) was added thereto at 70 ℃ to carry out a reaction for 4.5 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and reprecipitated, filtered and dried under strong stirring using 4,500mL of methanol, thereby recovering the polyfunctional vinyl aromatic copolymer. The obtained polyfunctional vinyl aromatic copolymer was weighed, and it was confirmed that 212.6g of a polyfunctional vinyl aromatic copolymer C2A was obtained.

The obtained polyfunctional vinyl aromatic copolymer C2A had Mn 596, Mw 1750 and Mw/Mn 2.93. Copolymer C2A contained 1.96 mol% (2.19 wt%) of structural units derived from divinylbenzene, a total of 1.16 mol% (1.32 wt%) of structural units derived from ethylvinylbenzene, and 96.88 mol% (96.49 wt%) of structural units derived from indene. The content of the structural unit derived from divinylbenzene having a residual vinyl group contained in the polyfunctional vinyl aromatic copolymer C2A was 1.30 mol% (1.45 wt%).

Further, TMA measurement of the cured product showed that Tg was 178 ℃ and the softening temperature was 201 ℃. The weight loss at 350 ℃ was 2.45% by weight as determined by TGA. On the other hand, the compatibility with the epoxy resin was ≈ o.

The polyfunctional vinyl aromatic copolymer C2A was found to be solvent-soluble.

Comparative example 3A

320.5mL of DVB-810 (1.82 mol as a divinylbenzene component and 0.43 mol as an ethylvinylbenzene component), 0.28 mol (36.9mL) of n-butyl acetate, and 140mL of toluene were charged into a 1.0L reactor, and a solution prepared by dissolving 40 mmol of methanesulfonic acid in 0.12 mol (15.7mL) of n-butyl acetate was added thereto at 70 ℃ to carry out a reaction for 6 hours. After the polymerization solution was stopped by potassium hydroxide, activated alumina was filtered as a filter aid. Thereafter, devolatilization was carried out under reduced pressure at 60 ℃ to obtain 22.6g of a polyfunctional vinyl aromatic copolymer C3A.

The obtained polyfunctional vinyl aromatic copolymer C3A had Mn of 1085, Mw of 12400 and Mw/Mn of 11.4. The polyfunctional vinyl aromatic copolymer F contained 84.0 mol% (83.8 wt%) of a structural unit derived from divinylbenzene and a total of 16.0 mol% (16.2 wt%) of a structural unit derived from ethylvinylbenzene. The content of the structural unit derived from divinylbenzene having a residual vinyl group contained in the polyfunctional vinyl aromatic copolymer C3A was 53.8 mol% (53.6 wt%).

The cured product had a Tg of 82 ℃ and a softening temperature of 93 ℃. The weight loss at 350 ℃ was 8.25% by weight as determined by TGA. On the other hand, the compatibility with the epoxy resin was ≈ o.

The polyfunctional vinyl aromatic copolymer C3A was found to be solvent-soluble.

Example 4A

Into an autoclave (autoclave) having an internal volume of 0.5 liter and purged with nitrogen, 245g of cyclohexane, 2.5g of THF, 10g of styrene, 40g of 1, 3-butadiene and 0.10g of the copolymer 1A obtained in example 1A were charged. Polymerization was started by adding 5g of a cyclohexane solution containing 50mg of sec-butyllithium at 25 ℃. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 85 ℃.

Example 5A

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in purity was added thereto at 50 ℃ followed by 30 minutes and 45g of a cyclohexane solution containing 0.10g of the copolymer 1A obtained in example 1A was added thereto to prepare a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 85 ℃.

Example 6A

A polyfunctional anionic polymerization initiator was prepared by charging 200g of cyclohexane and 2.5g of THF into an autoclave reactor purged with nitrogen, adding 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in terms of purity at 50 ℃ and then adding 45g of a cyclohexane solution containing 0.050g of the copolymer 2A obtained in example 2 over 30 minutes. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 83 ℃. After the polymerization reaction was completed, 21mmol of BTESPA was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 80 ℃ for 5 minutes to obtain a polymer solution.

Example 7A

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in purity was added thereto at 50 ℃ followed by 30 minutes and 45g of a cyclohexane solution containing 0.30g of the copolymer 3A obtained in example 3A was added thereto to prepare a polyfunctional anionic polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 81 ℃. After the polymerization reaction was completed, 21mmol of BTESPA was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 80 ℃ for 5 minutes to obtain a polymer solution.

Comparative example 4A

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in purity was added thereto at 50 ℃ followed by 30 minutes and 45g of a cyclohexane solution containing 0.0375g of the copolymer C1A obtained in comparative example 1A was added thereto to prepare a polyfunctional anionic polymerization initiator. The prepared polyfunctional anionic polymerization initiator was substantially soluble in cyclohexane, but the generation of gel was also observed visually. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 82 ℃.

Comparative example 5A

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in purity was added thereto at 50 ℃ followed by 30 minutes and 45g of a cyclohexane solution containing 0.75g of the copolymer C2A obtained in comparative example 2A was added thereto to prepare a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel generation was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 78 ℃.

Comparative example 6A

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in purity was added thereto at 50 ℃ followed by 30 minutes and 45g of a cyclohexane solution containing 0.020g of the copolymer C3A obtained in comparative example 3A was added thereto to prepare a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be partially dissolved in cyclohexane, and the generation of gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 83 ℃.

In table 1A, the diene copolymer means a conjugated diene copolymer. The same is true in the other tables.

[ Table 1A ]

Example 8A

The conjugated diene copolymer 4A, the process oil, carbon black, zinc oxide, stearic acid and the antioxidant were kneaded at 155 ℃ and 60rpm for 4 minutes using a laboratory Laplace mixer (Labo Plastomill).

The kneaded mixture obtained by the above kneading was added with sulfur and a vulcanization accelerator, and kneaded at 70 ℃ and 60rpm for 1 minute using a laboratory plasbotto mixer (Labo Plastomill) to be vulcanized, thereby obtaining a crosslinked rubber 8A.

The blending ratio of each additive is shown in table 2A. The physical properties of the crosslinked rubber 8A are shown in table 3A.

Example 9A to example 11A, and comparative example 7A to comparative example 9A

Crosslinked rubbers 9A to 11A and crosslinked rubbers C7A to C9A were obtained in the same manner as in example 8A, except that the conjugated diene copolymer 5A, the conjugated diene copolymer 6A, the conjugated diene copolymer 7A, the conjugated diene copolymer C4A, the conjugated diene copolymer C5A, and the conjugated diene copolymer C6A synthesized in the above examples or comparative examples were used instead of the conjugated diene copolymer 4A.

The types of the conjugated diene copolymers used and the physical properties of the crosslinked rubbers 9A to 11A and the crosslinked rubbers C7A to C9A obtained are shown in table 3A.

[ Table 2A ]

Copolymer rubber	100.0
		Process oil	37.5
Zinc oxide	3.0
		Sulfur	1.8
Stearic acid	1.0
		Silicon dioxide	65.0
Carbon black	5.0
		Vulcanization accelerator	1.5
Anti-aging agent	1.0

In table 2A, the additives used are as follows.

Process oil: production of Diana Process oil (AC-12) by Diana Process oil

Sulfur: powdered sulfur produced by crane chemical industry

Zinc oxide: production of zinc white No. 1 from three-well metal mining industry

Stearic acid: preparation of solar oil

Silicon dioxide: ultra silicon (ULTRASIL) VN3, manufactured by Degussa (Degussa) Inc

Carbon black: nicotron #300 from Nippon Steel Carbon (NIPPON STEEL Carbon)

Vulcanization accelerator (b): n-tert-butylbenzothiazole-2-sulphenamides

Anti-aging agent: nockeslar (Nocceler) -NS (produced by Nocceler) in large-scale emerging chemical industry

[ Table 3A ]

	Conjugated diene copolymer	Crosslinked rubber	Index of tensile Strength	Abrasion resistance index
					Example 8A	4A	8A	107	106
Example 9A	5A	9A	109	108
					Example 10A	6A	10A	116	117
Example 11A	7A	11A	115	118
					Comparative example 7A	C4A	C7A	102	91
Comparative example 8A	C5A	C8A	100	100
					Comparative example 9A	C6A	C9A	101	87

In table 3A, the tensile strength index and the abrasion resistance index were obtained by setting the numerical value of the crosslinked rubber of comparative example 7A to 100. As is clear from table 3A, the rubber crosslinked product of the present invention using the polyfunctional vinyl aromatic copolymer of the present invention provides processability equivalent to or higher than that of the case of using divinylbenzene as a conventional branching agent, and is excellent in tensile strength and abrasion resistance in a vulcanized rubber blended with carbon black.

< embodiment of the second invention >

Example 1B

9.30g of DVB-630 (divinylbenzene content: 0.045 mol, ethylvinylbenzene content: 0.026 mol), 148.79g (1.43 mol) of styrene, and 1.50 mol (172.5mL) of n-propyl acetate were charged into a 1.0L reactor, and 200 mmol of boron trifluoride diethyl ether complex (25.1mL) was added thereto at 50 ℃ to carry out a reaction for 2.5 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and the copolymer was recovered to obtain 90.1g of a polyfunctional vinyl aromatic copolymer 1B.

The obtained polyfunctional vinyl aromatic copolymer 1B had Mn of 4140, Mw of 9550 and Mw/Mn of 2.31. By carrying out¹³C-NMR and¹H-NMR analysis revealed that the polyfunctional vinyl aromatic copolymer A contained 3.0 mol% (3.7 wt%) of a structural unit derived from divinylbenzene, 1.4 mol% (1.8 wt%) of a structural unit derived from ethylvinylbenzene, and 95.5 mol% (94.5 wt%) of a structural unit derived from styrene. The crosslinking structural unit (a2) derived from a divinylaromatic compound represented by the formula (2) was 0.24 mol% (0.30 wt%), and thus the degree of crosslinking was 0.08. Further, the structural unit derived from divinylbenzene having a residual vinyl group (a1) contained in the polyfunctional vinyl aromatic copolymer 1B was 2.76 mol% (3.40 wt%), and therefore, the molar fraction of the structural unit containing a vinyl group (a1) with respect to the total of the structural unit (a) and the structural unit (B) was 0.028.

Further, the result of TMA measurement of the cured product is Tg: 105 ℃ and a softening temperature of 128 ℃.

The weight loss at 350 ℃ was 1.36% by weight as determined by TGA. A sample prepared by dissolving 0.5g of the polyfunctional vinyl aromatic copolymer 1B in 100g of toluene was placed in a quartz cell, and the haze value was measured by an integrating sphere type light transmittance measuring instrument using toluene as a reference sample and was 0.00.

Example 2B

18.60g of DVB-630 (divinylbenzene content: 0.090 mol, ethylvinylbenzene content: 0.053 mol), 141.34g (1.36 mol) of styrene, and 1.00 mol (115.0mL) of n-propyl acetate were charged into a 1.0L reactor, and 50 mmol of boron trifluoride diethyl ether complex (6.1mL) was added thereto at 60 ℃ to carry out a reaction for 3.0 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and the copolymer was recovered to obtain 95.8g of a polyfunctional vinyl aromatic copolymer 2B.

The polyfunctional vinyl aromatic copolymer 2B had Mn of 2620, Mw of 11800, and Mw/Mn of 4.51, and contained 7.37 mol% (8.97 wt%) of structural units derived from divinylbenzene, 3.34 mol% (4.12 wt%) of structural units derived from ethylvinylbenzene, and 89.3 mol% (86.9 wt%) of structural units derived from styrene. The crosslinking structural unit (a2) was 1.55 mol% (1.82 wt%), the degree of crosslinking was 0.21, the vinyl group-containing structural unit (a1) was 5.82 mol% (7.15 wt%), and the mole fraction of the structural unit (a1) was 0.058.

The cured product had a Tg of 158 ℃ and a softening temperature of 265 ℃. The weight loss at 350 ℃ was 1.28% by weight.

The haze value of the polyfunctional vinyl aromatic copolymer 2B was 0.01.

Example 3B

31.00g of DVB-630 (divinylbenzene content: 0.150 mol, ethylvinylbenzene content: 0.088 mol), 131.43g (1.262 mol) of styrene, and 1.50 mol (172.5mL) of n-propyl acetate were charged into a 1.0L reactor, and 60 mmol of boron trifluoride diethyl ether complex (7.5mL) was added thereto at 55 ℃ to carry out a reaction for 5.0 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and the copolymer was recovered to obtain 96.3g of a polyfunctional vinyl aromatic copolymer 3B.

The polyfunctional vinyl aromatic copolymer 3B had Mn of 2950, Mw of 13400 and Mw/Mn of 4.54. Contains 11.63 mol% (13.91 wt%) of a structural unit derived from divinylbenzene, 5.87 mol% (7.13 wt%) in total of a structural unit derived from ethylvinylbenzene, and 82.50 mol% (78.96 wt%) of a structural unit derived from styrene. The crosslinking structural unit (a2) was 3.14 mol% (3.76 wt%), and the degree of crosslinking was 0.27. Further, the structural unit (a1) was 8.49 mol% (10.16 wt%), and the mole fraction of the vinyl group-containing structural unit (a1) was 0.085.

The cured product had a Tg of 165 ℃ and a softening temperature of 280 ℃ or higher, and the weight loss at 350 ℃ was 1.46% by weight.

The haze value of the polyfunctional vinyl aromatic copolymer 3B was 0.04.

Example 4B

46.49g of DVB-630 (divinylbenzene content: 0.225 mol, ethylvinylbenzene content: 0.132 mol), 119.03g (1.143 mol) of styrene, and 1.50 mol (172.5mL) of n-propyl acetate were charged into a 1.0L reactor, and 60 mmol of boron trifluoride diethyl ether complex (7.54mL) was added thereto at 50 ℃ to carry out a reaction for 3.5 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, and devolatilized at 60 ℃ under reduced pressure to recover the copolymer, thereby obtaining 96.10g of a polyfunctional vinyl aromatic copolymer 4B.

The polyfunctional vinyl aromatic copolymer 4B had Mn of 3870, Mw of 23600 and Mw/Mn of 6.10. Containing 20.64 mol% (23.98 wt%) of structural units derived from divinylbenzene, 9.09 mol% (10.72 wt%) of structural units derived from ethylvinylbenzene, and 70.27 mol% (65.30 wt%) of structural units derived from styrene. The crosslinking structural unit (a2) was 6.61 mol% (7.67 wt%), the degree of crosslinking was 0.32, the vinyl group-containing structural unit (a1) was 14.04 mol% (16.31 wt%), and the mole fraction of the vinyl group-containing structural unit (a1) was 0.140.

The cured product had a Tg of 178 ℃ and a softening temperature of 280 ℃ or higher, and the weight loss at 350 ℃ was 1.53 wt%.

The haze value of the polyfunctional vinyl aromatic copolymer 4B was 0.07.

Example 5B

77.49g of DVB-630 (divinylbenzene content: 0.375 mol, ethylvinylbenzene content: 0.220 mol), 94.23g (0.905 mol) of styrene, and 1.57 mol (180.2mL) of n-propyl acetate were charged into a 1.0L reactor, and 23.3 mmol of boron trifluoride diethyl ether complex (2.93mL) was added thereto at 50 ℃ to carry out a reaction for 5.25 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and the copolymer was recovered to obtain 76.19g of a polyfunctional vinyl aromatic copolymer 5B.

The polyfunctional vinyl aromatic copolymer 5B had Mn of 4230, Mw of 26200 and Mw/Mn of 6.19. Containing 39.29 mol% (43.12 wt%) of structural units derived from divinylbenzene, 15.08 mol% (16.81 wt%) of structural units derived from ethylvinylbenzene, and 45.63 mol% (40.07 wt%) of structural units derived from styrene.

The crosslinking structural unit (a2) was 16.89 mol% (18.54 wt%), the degree of crosslinking was 0.43, the vinyl group-containing structural unit (a1) was 22.39 mol% (24.58 wt%), and the mole fraction of the structural unit (a1) was 0.224.

The cured product had no Tg, a softening temperature of 280 ℃ or higher, and a weight loss at 350 ℃ of 1.61 wt%.

The haze value of the polyfunctional vinyl aromatic copolymer 5B was 0.09.

Comparative example 1B

The polyfunctional vinyl aromatic copolymer C1B had Mn of 1085, Mw of 12400 and Mw/Mn of 11.4, and contained 84.0 mol% (83.8 wt%) of structural units derived from divinylbenzene, in total 16.0 mol% (16.2 wt%) of structural units derived from ethylvinylbenzene. The crosslinking structural unit (a2) was 2.60 mol% (2.59 wt%), the degree of crosslinking was 0.031, the vinyl group-containing structural unit (a1) was 11.40 mol% (11.37 wt%), and the mole fraction of the vinyl group-containing structural unit (a1) was 0.114.

The cured product had a Tg of 82 ℃, a softening temperature of 93 ℃ and a weight loss at 350 ℃ of 8.25 wt%. On the other hand, the compatibility with the epoxy resin was ≈ o.

The haze value of the polyfunctional vinyl aromatic copolymer C1B was 0.02.

Comparative example 2B

1.5 moles (195.3g) of divinylbenzene, 0.88 moles (114.7g) of ethylvinylbenzene, 12.6 moles (1314.3g) of styrene and 15.0 moles (1532.0g) of n-propyl acetate were charged into a 5.0L reactor, and 600 mmol of boron trifluoride diethyl ether complex was added thereto at 70 ℃ to carry out a reaction for 4 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, and devolatilized under reduced pressure at 60 ℃ to recover a copolymer. The obtained copolymer was weighed, and it was confirmed that 820.8g of copolymer C2B was obtained.

Copolymer C2B had an Mn of 1490, an Mw of 12600 and an Mw/Mn of 8.44. In the copolymer G, a structural unit derived from divinylbenzene is contained: 11.3 mol% (13.5 wt%), structural units derived from ethylvinylbenzene: 5.79 mol% (7.04 wt%), and structural units derived from styrene: 82.9 mol% (79.4 wt%).

The crosslinking structural unit (a2) was 5.86 mol% (7.02 wt%), the degree of crosslinking was 0.52, the vinyl group-containing structural unit (a1) was 5.41 mol% (6.48 wt%), and the mole fraction of the vinyl group-containing structural unit (a1) was 0.054.

The cured product was Tg: 162 ℃ and a softening temperature of 280 ℃ or higher, and a weight loss at 350 ℃ of 1.86 wt%.

The haze value of the polyfunctional vinyl aromatic copolymer C2B was 0.14.

Comparative example 3B

2.25 moles (292.9g) of divinylbenzene, 1.32 moles (172.0g) of ethylvinylbenzene, 11.4 moles (1190.3g) of styrene and 15.0 moles (1532.0g) of n-propyl acetate were charged into a 5.0L reactor, and 600 mmol of boron trifluoride diethyl ether complex was added thereto at 70 ℃ to conduct a reaction for 4 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, and devolatilized under reduced pressure at 60 ℃ to recover a copolymer. The obtained copolymer was weighed, and it was confirmed that 860.8g of copolymer C3B was obtained.

Copolymer C3B had Mn of 2060, Mw of 30700 and Mw/Mn of 14.9. In the copolymer H, the structural unit derived from divinylbenzene is contained: 20.92 mol% (24.29 wt%), structural units derived from ethylvinylbenzene: 9.06 mol% (10.68 wt%), and structural units derived from styrene: 70.02 mol% (65.03 wt%).

The crosslinking structural unit (a2) was 11.30 mol% (13.12 wt%), the degree of crosslinking was 0.54, the vinyl group-containing structural unit (a1) was 9.62 mol% (11.17 wt%), and the mole fraction of the vinyl group-containing structural unit (a1) was 0.096.

The cured product had no Tg, a softening temperature of 280 ℃ or higher, and a weight loss at 350 ℃ of 2.11 wt%.

The haze value of the polyfunctional vinyl aromatic copolymer C3B was 0.17.

Comparative example 4B

3.1 moles (404.5g) of divinylbenzene, 1.8 moles (237.6g) of ethylvinylbenzene, 7.5 moles (780.7g) of styrene and 13.0 moles (1325.7g) of n-propyl acetate were charged into a 5.0L reactor, and 193 mmol of boron trifluoride diethyl ether complex was added thereto at 70 ℃ to conduct a reaction for 4 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, and devolatilized under reduced pressure at 60 ℃ to recover a copolymer. The obtained copolymer was weighed, and it was confirmed that 689.2g of a copolymer C4B was obtained.

The copolymer C4B had Mn of 2940, Mw of 39500 and Mw/Mn of 13.4. In copolymer C4B, the structural units derived from divinylbenzene were contained: 36.8 mol% (40.7 wt%), structural units derived from ethylvinylbenzene: 14.5 mol% (16.3 wt%), and structural units derived from styrene: 48.6 mol% (43.0 wt%).

The crosslinking structural unit (a2) was 20.99 mol% (23.20 wt%), the degree of crosslinking was 0.57, the vinyl group-containing structural unit (a1) was 15.84 mol% (17.50 wt%), and the mole fraction of the vinyl group-containing structural unit (a1) was 0.158.

The cured product had no Tg, a softening temperature of 280 ℃ or higher, and a weight loss at 350 ℃ of 2.23 wt%.

The haze value of the polyfunctional vinyl aromatic copolymer C4B was 0.21.

Example 6B

Into an autoclave reactor having an internal volume of 0.5 liter purged with nitrogen, 245g of cyclohexane, 2.5g of THF, 10g of styrene, 40g of 1, 3-butadiene, and 0.50g of the polyfunctional vinyl aromatic copolymer 1B obtained in example 1B were charged. Polymerization was started by adding 5g of a cyclohexane solution containing 50mg of sec-butyllithium at 25 ℃. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 85 ℃.

Example 7B

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ followed by 30 minutes addition of 45g of a cyclohexane solution containing 0.50g of the polyfunctional vinyl aromatic copolymer 1B obtained in example 1B to prepare a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 85 ℃.

Example 8B

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ to prepare 45g of a cyclohexane solution containing 0.30g of the polyfunctional vinyl aromatic copolymer 2B obtained in example 2B over 30 minutes, thereby preparing a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 85 ℃.

Example 9B

Example 10B

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ to prepare 45g of a cyclohexane solution containing 0.35g of the polyfunctional vinyl aromatic copolymer 2B obtained in example 2B over 30 minutes, thereby preparing a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 81 ℃. After the polymerization reaction was completed, 21mmol of BTESPA was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 80 ℃ for 5 minutes to obtain a polymer solution.

Example 11B

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in purity was added thereto at 50 ℃ followed by 30 minutes and 45g of a cyclohexane solution containing 0.030g of the polyfunctional vinyl aromatic copolymer 3B obtained in example 3B was added to prepare a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was substantially soluble in cyclohexane, but the generation of gel was also observed visually. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 82 ℃.

After the polymerization reaction was completed, 21mmol of BTESPA was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 80 ℃ for 5 minutes to obtain a polymer solution. After confirming that the polymerization conversion rate reached 99%, 50mg (0.83mmol) of isopropyl alcohol was added to stop the polymerization, and BHT was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer 11B. The physical properties of the obtained conjugated diene copolymer 11B are shown in table 1B.

Example 12B

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ followed by 30 minutes addition of 45g of a cyclohexane solution containing 0.25g of the polyfunctional vinyl aromatic copolymer 4B obtained in example 4B to prepare a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel generation was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 81 ℃.

Example 13B

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ followed by 30 minutes addition of 45g of a cyclohexane solution containing 0.15g of the polyfunctional vinyl aromatic copolymer 5B obtained in example 5B to prepare a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be partially dissolved in cyclohexane, and the generation of gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 81 ℃.

Comparative example 5B

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ followed by 30 minutes addition of 45g of a cyclohexane solution containing 0.5g of the polyfunctional vinyl aromatic copolymer C1B obtained in comparative example 1B to prepare a polyfunctional anionic polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be partially dissolved in cyclohexane, and the generation of gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 84 ℃.

Comparative example 6B

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in purity was added thereto at 50 ℃ followed by 30 minutes addition of 45g of a cyclohexane solution containing 0.030g of the polyfunctional vinyl aromatic copolymer C2B obtained in comparative example 2B to prepare a polyfunctional anionic polymerization initiator. The prepared polyfunctional anionic polymerization initiator was substantially soluble in cyclohexane, but the generation of gel was also observed visually. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 83 ℃. After the polymerization reaction was completed, 21mmol of BTESPA was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 80 ℃ for 5 minutes to obtain a polymer solution.

Comparative example 7B

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ followed by 30 minutes addition of 45g of a cyclohexane solution containing 0.25g of the polyfunctional vinyl aromatic copolymer C3B obtained in comparative example 3B to prepare a polyfunctional anionic polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel generation was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 83 ℃.

Comparative example 8B

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 2.5g of THF, and 5g of a cyclohexane solution containing 50mg (0.78mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ followed by 30 minutes addition of 45g of a cyclohexane solution containing 0.15g of the polyfunctional vinyl aromatic copolymer C4B obtained in comparative example 4B to prepare a polyfunctional anionic polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be partially dissolved in cyclohexane, and the generation of gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 83 ℃.

[ Table 1B ]

Example 14B

The conjugated diene copolymer 6B, process oil, carbon black, zinc oxide, stearic acid and an antioxidant were kneaded at 155 ℃ and 60rpm for 4 minutes using a laboratory Laplace mixer (Labo Plastomill).

The kneaded mixture obtained by the above kneading was added with sulfur and a vulcanization accelerator, and kneaded at 70 ℃ and 60rpm for 1 minute using a laboratory plasbox mixer (Labo Plastomill) to be vulcanized, thereby obtaining a crosslinked rubber 14B.

The additives and the blending ratio were the same as those in Table 2A. The physical properties of the crosslinked rubber 14B are shown in table 3B.

Example 15B to example 21B, and comparative example 9B to comparative example 12B

Crosslinked rubbers 14B to 21B, and crosslinked rubbers C9B to C12B were obtained in the same manner as in example 14B, except that the conjugated diene copolymer 7B to the conjugated diene copolymer 13B, and the conjugated diene copolymer C5B to the conjugated diene copolymer C8B synthesized in the above examples or comparative examples were used instead of the conjugated diene copolymer 6B.

The types of the conjugated diene copolymers used and the physical properties of the crosslinked rubbers 14B to 21B and the crosslinked rubbers C9B to C12B thus obtained are shown in table 3B.

[ Table 3B ]

As is apparent from Table 3B, the rubber vulcanizate containing carbon black and the rubber vulcanizate of the present invention in which the polyfunctional vinyl aromatic copolymer of the present invention was used imparted processability equivalent to or higher than that of divinylbenzene, which is a conventional branching agent, was excellent in tensile strength and abrasion resistance.

< embodiment of the third invention >

Example 1C

31.00g of DVB-630 (divinylbenzene content: 0.150 mol, ethylvinylbenzene (mixture of intermediate and counterpart) content: 0.088 mol), 65.72g (0.631 mol) of styrene, 70.80g (0.631 mol) of diisobutylene, 60 mmol (6.90mL) of n-propyl acetate, and 48.55g (0.527 mol) of toluene were charged into a 500mL reactor, and 15.2 mmol of boron trifluoride diethyl ether complex (1.91mL) was added thereto at 70 ℃ to carry out a reaction for 2.0 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and the copolymer was recovered to obtain 60.6g of a polyfunctional vinyl aromatic copolymer 1C.

The obtained polyfunctional vinyl aromatic copolymer 1C had Mn of 941, Mw of 2850 and Mw/Mn of 3.03. By carrying out¹³C-NMR and¹H-NMR analysis revealed that the polyfunctional vinyl aromatic copolymer A contained 19.0 mol% (21.8 wt%) of a structural unit derived from divinylbenzene, 8.3 mol% (9.6 wt%) of a structural unit derived from ethylvinylbenzene, 48.6 mol% (44.6 wt%) of a structural unit derived from styrene, and 24.2 mol% (24.0 wt%) of a structural unit derived from diisobutylene. The crosslinking structural unit (a2) derived from a divinylaromatic compound represented by the formula (2) was 4.6 mol% (5.2 wt%), and thus the crosslinking degree (a2/a) was 0.24. Further, the structural unit derived from divinylbenzene having a residual vinyl group (a1) contained in the polyfunctional vinyl aromatic copolymer 1C was 14.4 mol% (16.5 wt%), and therefore, the molar fraction of the structural unit containing a vinyl group (a1) to the total of the structural unit (a), the structural unit (b), and the structural unit (C) was 0.144.

Further, the result of TMA measurement of the cured product is Tg: 167 ℃ and the softening temperature is above 280 ℃.

The weight loss at 350 ℃ was 1.41% by weight as determined by TGA. A sample prepared by dissolving 0.5g of the polyfunctional vinyl aromatic copolymer 1C in 100g of toluene was placed in a quartz cell, and the haze value was measured by an integrating sphere type light transmittance measuring instrument using toluene as a reference sample and was 0.02.

Example 2C

46.49g of DVB-630 (divinylbenzene content: 0.225 mol, ethylvinylbenzene content: 0.132 mol), 53.33g (0.512 mol) of styrene, 70.80g (0.631 mol) of diisobutylene, 60 mmol (6.90mL) of n-propyl acetate, and 48.55g (0.527 mol) of toluene were charged into a 500mL reactor, and 10.0 mmol of boron trifluoride diethyl ether complex (1.26mL) was added thereto at 70 ℃ to carry out a reaction for 2.0 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and the copolymer was recovered to obtain 66.4g of a polyfunctional vinyl aromatic copolymer 2C.

The obtained polyfunctional vinyl aromatic copolymer 2C had Mn of 1240, Mw of 4980 and Mw/Mn of 4.02. By carrying out¹³C-NMR and¹H-NMR analysis revealed that the polyfunctional vinyl aromatic copolymer B contained 28.2 mol% (31.5 wt%) of a structural unit derived from divinylbenzene, 12.2 mol% (13.8 wt%) of a structural unit derived from ethylvinylbenzene, 37.6 mol% (33.6 wt%) of a structural unit derived from styrene, and 22.0 mol% (21.1 wt%) of a structural unit derived from diisobutylene. The crosslinking structural unit (a2) derived from a divinylaromatic compound represented by the formula (2) was 7.6 mol% (8.5 wt%), and thus the degree of crosslinking was 0.27. Further, since the structural unit derived from divinylbenzene having a residual vinyl group (a1) included in the polyfunctional vinyl aromatic copolymer 2C was 20.6 mol% (23.0 wt%), the molar fraction of the structural unit containing a vinyl group (a1) to the total of the structural unit (a), the structural unit (b), and the structural unit (C) was 0.206.

Further, the result of TMA measurement of the cured product is Tg: 176 ℃ and the softening temperature is above 280 ℃.

The weight loss at 350 ℃ was 1.32% by weight as determined by TGA. A sample prepared by dissolving 0.5g of the polyfunctional vinyl aromatic copolymer 2C in 100g of toluene was placed in a quartz cell, and the haze value was measured by an integrating sphere type light transmittance measuring instrument using toluene as a reference sample and was 0.03.

Example 3C

62.00g of DVB-630 (divinylbenzene content: 0.300 mol, ethylvinylbenzene content: 0.176 mol), 40.92g (0.393 mol) of styrene, 70.80g (0.631 mol) of diisobutylene, 60 mmol (6.90mL) of n-propyl acetate, and 48.55g (0.527 mol) of toluene were charged into a 500mL reactor, and 8.2 mmol of boron trifluoride diethyl ether complex (1.03mL) was added thereto at 70 ℃ to carry out a reaction for 1.5 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and the copolymer was recovered to obtain 56.3g of a polyfunctional vinyl aromatic copolymer 3C.

The obtained polyfunctional vinyl aromatic copolymer 3C had Mn of 1430, Mw of 5490 and Mw/Mn of 3.84. By carrying out¹³C-NMR and¹H-NMR analysis showed that the polyfunctional vinyl aromatic copolymer C contained 39.4 mol% (42.6 wt%) of a structural unit derived from divinylbenzene, 15.9 mol% (17.4 wt%) of a structural unit derived from ethylvinylbenzene, 25.7 mol% (22.2 wt%) of a structural unit derived from styrene, and 19.1 mol% (17.8 wt%) of a structural unit derived from diisobutylene. The crosslinking structural unit (a2) derived from a divinylaromatic compound represented by the formula (2) was 11.4 mol% (12.3 wt%), and thus the degree of crosslinking was 0.29. Further, since the structural unit derived from divinylbenzene having a residual vinyl group (a1) included in the polyfunctional vinyl aromatic copolymer 3C was 28.0 mol% (30.2 wt%), the molar fraction of the structural unit containing a vinyl group (a1) to the total of the structural unit (a), the structural unit (b), and the structural unit (C) was 0.280.

Further, the result of TMA measurement of the cured product is Tg: 183 ℃ and the softening temperature is above 280 ℃.

The weight loss at 350 ℃ was 1.28% as determined by TGA. A sample prepared by dissolving 0.5g of the polyfunctional vinyl aromatic copolymer 3C in 100g of toluene was placed in a quartz cell, and the haze value was 0.05 when the haze (haze) was measured using an integrating sphere type light transmittance measuring instrument using toluene as a reference sample.

Comparative example 1C

The polyfunctional vinyl aromatic copolymer C1C had Mn of 1085, Mw of 12400 and Mw/Mn of 11.4, and contained 84.0 mol% (83.8 wt%) of structural units derived from divinylbenzene, in total 16.0 mol% (16.2 wt%) of structural units derived from ethylvinylbenzene. The crosslinking structural unit (a2) was 2.60 mol% (2.59 wt%), the degree of crosslinking was 0.031, the vinyl group-containing structural unit (a1) was 11.40 mol% (11.37 wt%), and the mole fraction of the vinyl group-containing structural unit (a1) was 0.114.

The cured product had a Tg of 82 ℃, a softening temperature of 93 ℃ and a weight loss at 350 ℃ of 8.25 wt%. On the other hand, the compatibility with the epoxy resin was ≈ o.

The haze value of the polyfunctional vinyl aromatic copolymer C1C was 0.02.

Comparative example 2C

Copolymer C2C had an Mn of 1490, an Mw of 12600 and an Mw/Mn of 8.44. In copolymer C2C, the structural units derived from divinylbenzene were contained: 11.3 mol% (13.5 wt%), structural units derived from ethylvinylbenzene: 5.79 mol% (7.04 wt%), and structural units derived from styrene: 82.9 mol% (79.4 wt%).

The cured product was Tg: 162 ℃ and a softening temperature of 280 ℃ or higher, and a weight loss at 350 ℃ of 1.86 wt%.

The haze value of the polyfunctional vinyl aromatic copolymer C2C was 0.14.

Comparative example 3C

Copolymer C3C had Mn of 2060, Mw of 30700 and Mw/Mn of 14.9. In copolymer C3C, the structural units derived from divinylbenzene were contained: 20.92 mol% (24.29 wt%), structural units derived from ethylvinylbenzene: 9.06 mol% (10.68 wt%), and structural units derived from styrene: 70.02 mol% (65.03 wt%).

The cured product had no Tg, a softening temperature of 280 ℃ or higher, and a weight loss at 350 ℃ of 2.11 wt%.

The haze value of the polyfunctional vinyl aromatic copolymer C3C was 0.17.

Comparative example 4C

The copolymer C4C had Mn of 2940, Mw of 39500 and Mw/Mn of 13.4. In copolymer C4C, the structural units derived from divinylbenzene were contained: 36.8 mol% (40.7 wt%), structural units derived from ethylvinylbenzene: 14.5 mol% (16.3 wt%), and structural units derived from styrene: 48.6 mol% (43.0 wt%).

The cured product had no Tg, a softening temperature of 280 ℃ or higher, and a weight loss at 350 ℃ of 2.23 wt%.

The haze value of the functional vinyl aromatic copolymer C4C was 0.21.

Example 4C

Into an autoclave reactor having an internal volume of 0.5 liter purged with nitrogen, 245g of cyclohexane, 0.5g of THF, 10g of styrene, 40g of 1, 3-butadiene, and 0.10g of the polyfunctional vinyl aromatic copolymer 1C obtained in example 1C were charged. Polymerization was started by adding 5g of a cyclohexane solution containing 10mg (0.16mmol) of sec-butyllithium at 25 ℃. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 81 ℃.

After confirming that the polymerization conversion rate reached 99%, 50mg of isopropyl alcohol was added to stop the polymerization, and 2, 6-di-tert-butyl-p-cresol (BHT) was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer 4C. 0.5g of the obtained conjugated diene copolymer 4C was dissolved in 100mL of toluene, 1.0g of a 0.2 wt% Sudan (Sudan) III toluene solution was added thereto to color the solution, the solution was filtered through a 0.2 μm Polytetrafluoroethylene (PTFE) membrane filter, and observation was made on the filtered membrane filter by an instant dynamic microscope, whereby it was confirmed that no microgel was produced. The physical properties of the conjugated diene copolymer 4C are shown in table 1C.

Example 5C

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 0.5g of THF, and 5g of a cyclohexane solution containing 10mg (0.16mmol) of n-butyllithium in terms of purity was added at 50 ℃ to prepare 45g of a cyclohexane solution containing 0.10g of the polyfunctional vinyl aromatic copolymer 1C obtained in example 1C over a period of 30 minutes, thereby preparing a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 80 ℃.

After confirming that the polymerization conversion rate reached 99%, 50mg (0.83mmol) of isopropyl alcohol was added to stop the polymerization, and BHT was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer 5C. 0.5g of the obtained conjugated diene copolymer 5C was dissolved in 100mL of toluene, 1.0g of a 0.2 wt% Sudan (Sudan) III toluene solution was added thereto to color the solution, the solution was filtered through a 0.2 μm PTFE membrane filter, and the filtered membrane filter was observed by an instant dynamic microscope, whereby it was confirmed that no microgel was produced. Physical properties of the conjugated diene copolymer 5C are shown in table 1C.

Example 6C

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 0.5g of THF, and 5g of a cyclohexane solution containing 10mg (0.16mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ followed by 30 minutes and 45g of a cyclohexane solution containing 0.085g of the polyfunctional vinyl aromatic copolymer 2C obtained in example 2C was added to prepare a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 83 ℃.

After confirming that the polymerization conversion rate reached 99%, 50mg (0.83mmol) of isopropyl alcohol was added to stop the polymerization, and BHT was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer 6C. 0.5g of the obtained conjugated diene copolymer 6C was dissolved in 100mL of toluene, 1.0g of a 0.2 wt% Sudan (Sudan) III toluene solution was added thereto to color the solution, the solution was filtered through a 0.2 μm PTFE membrane filter, and observation was made on the filtered membrane filter by an instant dynamic microscope, whereby it was confirmed that no microgel was produced. Physical properties of the conjugated diene copolymer 6C are shown in table 1C.

Example 7C

After confirming that the polymerization conversion rate reached 99%, 50mg (0.83mmol) of isopropyl alcohol was added to stop the polymerization, and BHT was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer 7C. 0.5g of the obtained conjugated diene copolymer 7C was dissolved in 100mL of toluene, 1.0g of a 0.2 wt% Sudan (Sudan) III toluene solution was added thereto to color the solution, the solution was filtered through a 0.2 μm PTFE membrane filter, and observation was made on the filtered membrane filter by an instant dynamic microscope, whereby it was confirmed that no microgel was produced. Physical properties of the conjugated diene copolymer 7C are shown in table 1C.

Example 8C

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 0.5g of THF, and 5g of a cyclohexane solution containing 10mg (0.16mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ followed by 30 minutes and 45g of a cyclohexane solution containing 0.085g of the polyfunctional vinyl aromatic copolymer 2C obtained in example 2C was added to prepare a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 82 ℃. After the polymerization reaction was completed, 21mmol of BTESPA was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 80 ℃ for 5 minutes to obtain a polymer solution.

After confirming that the polymerization conversion rate reached 99%, 50mg (0.83mmol) of isopropyl alcohol was added to stop the polymerization, and BHT was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer 8C. 0.5g of the obtained conjugated diene copolymer 8C was dissolved in 100mL of toluene, 1.0g of a 0.2 wt% Sudan (Sudan) III toluene solution was added thereto to color the solution, the solution was filtered through a 0.2 μm PTFE membrane filter, and observation was made on the filtered membrane filter by an instant dynamic microscope, whereby it was confirmed that no microgel was produced. Physical properties of the conjugated diene copolymer 8C are shown in table 1C.

Example 9C

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 0.5g of THF, and 5g of a cyclohexane solution containing 10mg (0.16mmol) of n-butyllithium in terms of purity was added at 50 ℃ to prepare 45g of a cyclohexane solution containing 0.070g of the polyfunctional vinyl aromatic copolymer 3C obtained in example 3C over a period of 30 minutes, thereby preparing a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel generation was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 78 ℃. After the polymerization reaction was completed, 21mmol of BTESPA was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 80 ℃ for 5 minutes to obtain a polymer solution.

After confirming that the polymerization conversion rate reached 99%, 50mg (0.83mmol) of isopropyl alcohol was added to stop the polymerization, and BHT was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer 9C. 0.5g of the obtained conjugated diene copolymer 9C was dissolved in 100mL of toluene, 1.0g of a 0.2 wt% Sudan (Sudan) III toluene solution was added thereto to color the solution, the solution was filtered through a 0.2 μm PTFE membrane filter, and observation was made on the filtered membrane filter by an instant dynamic microscope, whereby it was confirmed that no microgel was produced. Physical properties of the conjugated diene copolymer 9C are shown in table 1C.

Comparative example 5C

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 0.5g of THF, and 5g of a cyclohexane solution containing 10mg (0.16mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ followed by 30 minutes addition of 45g of a cyclohexane solution containing 0.1g of the polyfunctional vinyl aromatic copolymer C1C obtained in comparative example 1C to prepare a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be partially dissolved in cyclohexane, and the generation of gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 84 ℃.

After confirming that the polymerization conversion rate reached 99%, 50mg (0.83mmol) of isopropyl alcohol was added to stop the polymerization, and BHT was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer C5C. 0.5g of the obtained conjugated diene copolymer C5C was dissolved in 100mL of toluene, 1.0g of a 0.2 wt% Sudan (Sudan) III toluene solution was added thereto to color the solution, the solution was filtered through a 0.2 μm PTFE membrane filter, and the formation of a microgel was observed on the filtered membrane filter by an instant dynamic microscope. Physical properties of the conjugated diene copolymer C5C are shown in table 1C.

Comparative example 6C

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 0.5g of THF, and 5g of a cyclohexane solution containing 10mg (0.16mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ followed by 30 minutes addition of 45g of a cyclohexane solution containing 0.08g of the polyfunctional vinyl aromatic copolymer C2C obtained in comparative example 2C to prepare a polyfunctional anionic polymerization initiator. The prepared polyfunctional anionic polymerization initiator was substantially soluble in cyclohexane, but the generation of gel was also observed visually. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 83 ℃. After the polymerization reaction was completed, 21mmol of BTESPA was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 80 ℃ for 5 minutes to obtain a polymer solution.

After confirming that the polymerization conversion rate reached 99%, 50mg (0.83mmol) of isopropyl alcohol was added to stop the polymerization, and BHT was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer C6C. 0.5g of the obtained conjugated diene copolymer C6C was dissolved in 100mL of toluene, 1.0g of a 0.2 wt% Sudan (Sudan) III toluene solution was added thereto to color the solution, the solution was filtered through a 0.2 μm PTFE membrane filter, and the formation of a microgel was observed on the filtered membrane filter by an instant dynamic microscope. Physical properties of the conjugated diene copolymer C6C are shown in table 1C.

Comparative example 7C

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 0.5g of THF, and 5g of a cyclohexane solution containing 10mg (0.16mmol) of n-butyllithium in terms of purity was added at 50 ℃ to prepare 45g of a cyclohexane solution containing 0.10g of the polyfunctional vinyl aromatic copolymer C3C obtained in comparative example 3C over 30 minutes, thereby preparing a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, but the generation of gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 83 ℃.

After confirming that the polymerization conversion rate reached 99%, 50mg (0.83mmol) of isopropyl alcohol was added to stop the polymerization, and BHT was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer C7C. 0.5g of the obtained conjugated diene copolymer C7C was dissolved in 100mL of toluene, 1.0g of a 0.2 wt% Sudan (Sudan) III toluene solution was added thereto to color the solution, the solution was filtered through a 0.2 μm PTFE membrane filter, and the formation of a microgel was observed on the filtered membrane filter by an instant dynamic microscope. Physical properties of the conjugated diene copolymer C7C are shown in table 1C.

Comparative example 8C

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 0.5g of THF, and 5g of a cyclohexane solution containing 10mg (0.16mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ followed by 30 minutes addition of 45g of a cyclohexane solution containing 0.08g of the polyfunctional vinyl aromatic copolymer C4C obtained in comparative example 4C to prepare a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be partially dissolved in cyclohexane, and the generation of gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 83 ℃.

After confirming that the polymerization conversion rate reached 99%, 50mg (0.83mmol) of isopropyl alcohol was added to stop the polymerization, and BHT was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer C8C. 0.5g of the obtained conjugated diene copolymer C8C was dissolved in 100mL of toluene, 1.0g of a 0.2 wt% Sudan (Sudan) III toluene solution was added thereto to color the solution, the solution was filtered through a 0.2 μm PTFE membrane filter, and the formation of a microgel was observed on the filtered membrane filter by an instant dynamic microscope. Physical properties of the conjugated diene copolymer C8C are shown in table 1C.

[ Table 1C ]

Example 10C

The conjugated diene copolymer 4C (copolymer rubber) synthesized in example 4C, process oil, carbon black, zinc oxide, stearic acid, and an antioxidant were blended, and kneaded at 155 ℃ and 60rpm for 4 minutes using a laboratory plasbotto mixer (Labo Plastomill).

The blending ratio of each additive is shown in table 2C. The physical properties of the crosslinked rubber 10C are shown in table 3C.

[ Table 2C ]

Copolymer rubber	100.0
		Process oil	37.5
Silicon dioxide	65.0
		Carbon black	5.0
Zinc oxide	3.0
		Stearic acid	1.0
Anti-aging agent	1.0
		Sulfur	1.8
Vulcanization accelerator	1.5

The additives used were as follows.

Process oil: production of Diana Process oil (AC-12) by Diana Process oil

Silicon dioxide: ultra silicon (ULTRASIL) VN3, manufactured by Degussa (Degussa) Inc

Carbon black: nicotron #300 from Nippon Steel Carbon (NIPPON STEEL Carbon)

Zinc oxide: production of zinc white No. 1 from three-well metal mining industry

Stearic acid: preparation of solar oil

Anti-aging agent: nockeslar (Nocceler) -NS (produced by Nocceler) in large-scale emerging chemical industry

Sulfur: powdered sulfur produced by crane chemical industry

Vulcanization accelerator (b): n-tert-butylbenzothiazole-2-sulphenamides

Example 11C to example 15C, and comparative example 9C to comparative example 12C

Crosslinked rubbers 11C to 15C, crosslinked rubbers C9C to C12C were obtained in the same manner as in example 10C, except that the conjugated diene copolymer 5C to the conjugated diene copolymer 9C and the conjugated diene copolymer C5C to the conjugated diene copolymer C8C synthesized in the above examples or comparative examples were used instead of the conjugated diene copolymer 4C.

The types of the conjugated diene copolymers used and the physical properties of the crosslinked rubbers 11C to 15C and the crosslinked rubbers C9C to C12C thus obtained are shown in table 3C.

[ Table 3C ]

As is clear from table 3C, the rubber crosslinked product of the present invention using the polyfunctional vinyl aromatic copolymer of the present invention provides the same or higher dispersibility of silica and adhesion at the interface as compared with the case of using divinylbenzene as a conventional branching agent, and therefore, the vulcanized rubber is excellent in tensile strength and abrasion resistance.

Example 16C

46.49g of DVB-630 (divinylbenzene content: 0.225 mol, ethylvinylbenzene content: 0.132 mol), 53.33g (0.512 mol) of styrene, 61.95g (0.631 mol) of 2-methyl-1-hexene, 60 mmol (6.90mL) of n-propyl acetate, and 48.55g (0.527 mol) of toluene were charged into a 500mL reactor, and 10.0 mmol of boron trifluoride diethyl ether complex (1.26mL) was added thereto at 70 ℃ to conduct a reaction for 2.0 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and the copolymer was recovered to obtain 64.8g of a polyfunctional vinyl aromatic copolymer 16C.

The obtained polyfunctional vinyl aromatic copolymer 16C had Mn of 1310, Mw of 5070 and Mw/Mn of 3.87. By passingTo carry out¹³C-NMR and¹H-NMR analysis revealed that the polyfunctional vinyl aromatic copolymer J contained 28.0 mol% (32.2 wt%) of a structural unit derived from divinylbenzene, 12.2 mol% (14.2 wt%) of a structural unit derived from ethylvinylbenzene, 32.5 mol% (35.3 wt%) of a structural unit derived from styrene, and 24.5 mol% (21.2 wt%) of a structural unit derived from 2-methyl-1-hexene.

The crosslinking structural unit (a2) derived from a divinylaromatic compound represented by the formula (2) was 8.1 mol% (9.3 wt%), and thus the degree of crosslinking was 0.29. Further, the structural unit derived from divinylbenzene having a residual vinyl group (a1) contained in the polyfunctional vinyl aromatic copolymer J was 19.9 mol% (22.8 wt%), and therefore, the molar fraction of the structural unit containing a vinyl group (a1) to the total of the structural unit (a), the structural unit (b), and the structural unit (c) was 0.199.

Further, the result of TMA measurement of the cured product is Tg: 168 ℃ and the softening temperature is above 280 ℃.

The weight loss at 350 ℃ was 1.41% by weight as determined by TGA. A sample prepared by dissolving 0.5g of the polyfunctional vinyl aromatic copolymer 16C in 100g of toluene was placed in a quartz cell, and the haze value was measured with an integrating sphere type light transmittance measuring instrument using toluene as a reference sample and was 0.04.

Example 17C

46.49g of DVB-630 (divinylbenzene content: 0.225 mol, ethylvinylbenzene content: 0.132 mol), 53.33g (0.512 mol) of styrene, 53.10g (0.631 mol) of 2-methyl-1-pentene, 60 mmol (6.90mL) of n-propyl acetate, and 48.55g (0.527 mol) of toluene were charged into a 500mL reactor, and 10.0 mmol of boron trifluoride diethyl ether complex (1.26mL) was added thereto at 70 ℃ to conduct a reaction for 2.0 hours. After the polymerization solution was stopped by an aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water, devolatilized at 60 ℃ under reduced pressure, and the copolymer was recovered to obtain 61.5g of a polyfunctional vinyl aromatic copolymer 17C.

The obtained polyfunctional vinyl aromatic copolymer 17C had Mn of 1280 and Mw of5260 the Mw/Mn is 4.11. By carrying out¹³C-NMR and¹H-NMR analysis revealed that the polyfunctional vinyl aromatic copolymer 17C contained 26.5 mol% (31.7 wt%) of a structural unit derived from divinylbenzene, 11.3 mol% (13.8 wt%) of a structural unit derived from ethylvinylbenzene, 35.3 mol% (33.8 wt%) of a structural unit derived from styrene, and 26.8 mol% (20.8 wt%) of a structural unit derived from 2-methyl-1-pentene.

The crosslinking structural unit (a2) derived from a divinylaromatic compound represented by the formula (2) was 7.2 mol% (8.6 wt%), and thus the degree of crosslinking was 0.27. Further, since the structural unit (a1) derived from divinylbenzene having a residual vinyl group contained in the polyfunctional vinyl aromatic copolymer B was 19.3 mol% (23.1 wt%), the molar fraction of the structural unit (a1) containing a vinyl group to the total of the structural unit (a), the structural unit (B) and the structural unit (c) was 0.193.

Further, the result of TMA measurement of the cured product is Tg: 171 ℃ and the softening temperature is above 280 ℃.

The weight loss at 350 ℃ was 1.38% as determined by TGA. A sample prepared by dissolving 0.5g of the polyfunctional vinyl aromatic copolymer 17C in 100g of toluene was placed in a quartz cell, and the haze value was measured by an integrating sphere type light transmittance measuring instrument using toluene as a reference sample and was 0.03.

Example 18C

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 0.5g of THF, and 5g of a cyclohexane solution containing 10mg (0.16mmol) of n-butyllithium in terms of purity was added at 50 ℃ to prepare 45g of a cyclohexane solution containing 0.085g of the polyfunctional vinyl aromatic copolymer 16C obtained in example 16C over 30 minutes, thereby preparing a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 82 ℃. After the polymerization reaction was completed, 21mmol of BTESPA was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 80 ℃ for 5 minutes to obtain a polymer solution.

After confirming that the polymerization conversion rate reached 99%, 50mg (0.83mmol) of isopropyl alcohol was added to stop the polymerization, and BHT was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer 18C. 0.5g of the obtained conjugated diene copolymer 18C was dissolved in 100mL of toluene, 1.0g of a 0.2 wt% Sudan (Sudan) III toluene solution was added thereto to color the solution, the solution was filtered through a 0.2 μm PTFE membrane filter, and observation was made on the filtered membrane filter by an instant dynamic microscope, whereby it was confirmed that no microgel was produced. The physical properties of the conjugated diene copolymer 18C are shown in table 4C.

Example 19C

A nitrogen-purged autoclave reactor was charged with 200g of cyclohexane and 0.5g of THF, and 5g of a cyclohexane solution containing 10mg (0.16mmol) of n-butyllithium in terms of purity was added thereto at 50 ℃ followed by 30 minutes and 45g of a cyclohexane solution containing 0.085g of the polyfunctional vinyl aromatic copolymer 17C obtained in example 17C was added to prepare a polyfunctional anion polymerization initiator. The prepared polyfunctional anionic polymerization initiator was able to be dissolved in cyclohexane, and no gel was observed. 10g of styrene from which impurities had been removed in advance and 40g of 1, 3-butadiene were added to start the polymerization. The temperature of the reaction solution was raised by the heat of polymerization, and the maximum temperature reached 82 ℃. After the polymerization reaction was completed, 21mmol of BTESPA was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 80 ℃ for 5 minutes to obtain a polymer solution.

After confirming that the polymerization conversion rate reached 99%, 50mg (0.83mmol) of isopropyl alcohol was added to stop the polymerization, and BHT was added to the reaction solution. Subsequently, the solvent was removed by steam stripping to obtain a conjugated diene copolymer 19C. 0.5g of the obtained conjugated diene copolymer 19C was dissolved in 100mL of toluene, 1.0g of a 0.2 wt% Sudan (Sudan) III toluene solution was added thereto to color the solution, the solution was filtered through a 0.2 μm PTFE membrane filter, and observation was made on the filtered membrane filter by an instant dynamic microscope, whereby it was confirmed that no microgel was produced. The physical properties of the conjugated diene copolymer 19C are shown in table 4C.

[ Table 4C ]

[ industrial applicability ]

The polyfunctional vinyl aromatic copolymer of the present invention can be used as a raw material for a conjugated diene copolymer. Furthermore, a crosslinked rubber composition obtained by crosslinking a conjugated diene copolymer containing a filler has excellent dispersibility of the filler and excellent mechanical strength and abrasion resistance, and therefore can be effectively used as an elastomer material such as a tire (particularly a tire tread), a cushion rubber, a rubber hose, a rubber roller, and a footwear material.

Further, the resin composition can be suitably used as a molding material, a resin modifier, and the like. In the fields of the electrical and electronic industry, the aerospace industry, and the like, they are provided as dielectric materials, insulating materials, heat-resistant materials, structural materials, and the like. Further, films and sheets coated with the curable resin composition containing the polyfunctional vinyl aromatic copolymer of the present invention can be suitably used for plastic optical parts, touch panels, flat panel displays, film-forming liquid crystal devices, and the like. The polyfunctional vinyl aromatic copolymer of the present invention is also useful as a modifier for improving the properties such as heat resistance, dielectric properties and optical properties of a thermoplastic resin or a curable resin composition used as a main material of a film, a sheet or a prepreg. The curable resin composition containing the polyfunctional vinyl aromatic copolymer of the present invention as a main material can be used by processing into films, sheets and prepregs. Furthermore, the curable resin composition containing the polyfunctional vinyl aromatic copolymer of the present invention can be used as various optical elements such as an optical waveguide and an optical lens.

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Polyfunctional vinyl aromatic copolymer, process for producing the same, copolymer rubber obtained therefrom, rubber composition, rubber crosslinked product, and tire member

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