Copolymer, method for producing copolymer, rubber composition, and tire
阅读说明：本技术 共聚物、共聚物的制造方法、橡胶组合物以及轮胎 (Copolymer, method for producing copolymer, rubber composition, and tire ) 是由 高野重永 奥利弗·塔迪芙 于 2018-11-29 设计创作，主要内容包括：本发明所要解决的问题为提供一种共聚物,其在低的应变区域中发热性降低,同时具有优异的耐磨耗性和耐龟裂生长性,并且展现出良好的加工性。根据本发明的该问题的解决方案为一种共聚物,其至少包含非共轭烯烃单元和共轭二烯单元并且其特征在于：所述非共轭烯烃单元的含量为40mol％以上；并且通过差示扫描量热计(DSC)测量的在100℃～150℃的源自所述非共轭烯烃单元的结晶度为4.0％以下。(The problem to be solved by the present invention is to provide a copolymer which is reduced in heat generation in a low strain region, while having excellent wear resistance and crack growth resistance, and exhibits good processability. The solution to this problem according to the invention is a copolymer comprising at least non-conjugated olefin units and conjugated diene units and characterized in that: the content of the non-conjugated olefin unit is 40 mol% or more; and a crystallinity derived from the non-conjugated olefin unit at 100 ℃ to 150 ℃ as measured by a Differential Scanning Calorimeter (DSC) is 4.0% or less.)
1. A copolymer comprising at least non-conjugated olefin units and conjugated diene units, wherein:
the content of the non-conjugated olefin unit is 40 mol% or more; and is
A crystallinity originating from the non-conjugated olefin unit in a temperature range of 100 ℃ to 150 ℃ as measured by a Differential Scanning Calorimeter (DSC) is 4.0% or less.
2. The copolymer of claim 1, further comprising aromatic vinyl units.
3. The copolymer of claim 1 or 2, wherein the non-conjugated olefin units are non-cyclic non-conjugated olefin units.
4. The copolymer of claim 3, wherein the acyclic nonconjugated olefin units consist only of ethylene units.
5. The copolymer according to any one of claims 1 to 4, wherein the conjugated diene units comprise 1, 3-butadiene units and/or isoprene units.
6. The copolymer of any of claims 1 to 5, wherein the conjugated diene units comprise only 1, 3-butadiene units.
7. The copolymer according to any one of claims 2 to 6, wherein the aromatic vinyl unit comprises a styrene unit.
8. The copolymer according to any one of claims 2 to 7, wherein the content of the non-conjugated olefin unit is in the range of 40 to 97 mol%, the content of the conjugated diene unit is in the range of 1 to 50 mol%, and the content of the aromatic vinyl unit is in the range of 2 to 35 mol%.
9. A method for producing a copolymer containing at least a non-conjugated olefin unit and a conjugated diene unit, wherein the method comprises the steps of:
curing the catalyst composition; and is
Copolymerizing at least a non-conjugated olefin compound and a conjugated diene compound in the presence of the thus-matured catalyst composition, the catalyst composition comprising:
a rare earth element-containing compound (A) containing a rare earth element compound or a reaction product resulting from a reaction between the rare earth element compound and a Lewis base;
at least one compound selected from the group consisting of an organometallic compound (B) represented by the following general formula (I), an ionic compound (C), and a halogen compound (D):
YR1 aR2 bR3 c…(I)
(in the general formula (I), Y represents a metal selected from the group consisting of group 1,2, 12 and 13 elements in the periodic Table, and R1And R2Each represents C1-10Hydrocarbon radicals or hydrogen atoms, R3Is represented by C1-10Hydrocarbyl radical, R1、R2And R3May be the same kind or different kinds, and when Y is a metal selected from group 1 elements of the periodic table, a ═ is1 and b-c-0, when Y is a metal selected from group 2 and group 12 elements of the periodic table, a-b-1 and c-0, and when Y is a metal selected from group 13 elements of the periodic table, a-b-c-1); and
at least one compound (E) selected from the group consisting of a non-conjugated olefin compound and a conjugated diene compound.
10. A method for producing a copolymer containing at least a non-conjugated olefin unit and a conjugated diene unit, the method comprising a step of copolymerizing at least a non-conjugated olefin compound and a conjugated diene compound in the presence of a catalyst composition comprising:
a rare earth element-containing compound (A) containing a rare earth element compound or a reaction product resulting from a reaction between the rare earth element compound and a Lewis base;
at least one compound selected from the group consisting of an organometallic compound (B) represented by the following general formula (I), an ionic compound (C), and a halogen compound (D):
YR1 aR2 bR3 c…(I)
(in the general formula (I), Y represents a metal selected from the group consisting of group 1,2, 12 and 13 elements in the periodic Table, and R1And R2Each represents C1-10Hydrocarbon radicals or hydrogen atoms, R3Is represented by C1-10Hydrocarbyl radical, R1、R2And R3May be the same kind or different kind, when Y is a metal selected from group 1 elements of the periodic table, a ═ 1 and b ═ c ═ 0, when Y is a metal selected from group 2 and group 12 elements of the periodic table, a ═ b ═ 1 and c ═ 0, and when Y is a metal selected from group 13 elements of the periodic table, a ═ b ═ c ═ 1); and
at least one compound (E') selected from the group consisting of a non-conjugated olefin compound and a conjugated diene compound, the non-conjugated olefin compound and the conjugated diene compound being different in kind from the non-conjugated olefin compound and the conjugated diene compound copolymerized in the copolymerization step.
11. The method for producing a copolymer according to claim 9 or 10, wherein the copolymer further contains an aromatic vinyl unit, and the copolymerization step includes copolymerizing the non-conjugated olefin compound, the conjugated diene compound, and an aromatic vinyl compound.
12. The method for producing a copolymer according to claim 11, wherein a content of the non-conjugated olefin unit of the copolymer is in a range of 40 to 97 mol%, a content of the conjugated diene unit is in a range of 1 to 50 mol%, and a content of the aromatic vinyl unit is in a range of 2 to 35 mol%.
13. The method for producing a copolymer according to any one of claims 9 to 12, wherein the catalyst composition further comprises aluminoxane (F).
14. The method for producing a copolymer according to any one of claims 9 to 13, wherein the compound (E) or the compound (E') is a non-conjugated olefin compound having three or more carbon atoms.
15. The method for producing a copolymer according to any one of claims 9 to 14, wherein the compound (E) or the compound (E') is a cyclic nonconjugated olefin compound.
16. The method for producing a copolymer according to any one of claims 9 to 15, wherein the compound (E) or the compound (E') is at least one selected from norbornene, 1, 3-butadiene and dicyclopentadiene.
17. A rubber composition comprising the copolymer according to any one of claims 1 to 8.
18. A tire using the rubber composition according to claim 17.
Technical Field
The present invention relates to a copolymer, a method for producing the copolymer, a rubber composition, and a tire.
Background
In general, rubber products (such as tires, conveyor belts, vibration-proof rubbers, vibration-isolating rubbers, and the like) require excellent durability (fracture resistance, abrasion resistance, and crack growth resistance, and the like) and weather resistance. Various rubber components and rubber compositions have been developed to meet this need for rubber articles as described above.
For example,
Reference list
Patent document
PTL 1：WO2012/014455
Disclosure of Invention
Problems to be solved by the invention
However, although the chain length of the non-conjugated olefin unit of the copolymer is an important factor affecting the heat generation property and processability of the copolymer in a low strain region,
In view of this, an object of the present invention is to provide a copolymer which is reduced in heat generation in a low strain region and exhibits good processability, while having excellent wear resistance and crack growth resistance.
Further, another object of the present invention is to provide a method for producing a copolymer, which allows production of a copolymer that has reduced heat generation in a low strain region and exhibits good processability, while having excellent wear resistance and crack growth resistance.
Still further, it is still another object of the present invention to provide a rubber composition capable of reducing the rolling resistance of a tire while having high wear resistance and high crack growth resistance, and a tire exhibiting low rolling resistance while having high wear resistance and high crack growth resistance.
Means for solving the problems
The present invention is designed to solve the above problems, and has the following main features.
The copolymer of the present invention is a copolymer containing at least a non-conjugated olefin unit and a conjugated diene unit, wherein:
wherein the content of the non-conjugated olefin unit is 40 mol% or more; and is
A crystallinity originating from the non-conjugated olefin unit in a temperature range of 100 ℃ to 150 ℃ as measured by a Differential Scanning Calorimeter (DSC) is 4.0% or less.
The copolymer of the present invention as described above has reduced heat generation in a low strain region and exhibits good processability while having excellent wear resistance and crack growth resistance.
Preferably, the copolymer of the present invention further comprises an aromatic vinyl unit. In this case, the chain length of the non-conjugated olefin unit can be easily shortened.
In a preferred example of the copolymer of the present invention, the non-conjugated olefin unit is a non-cyclic non-conjugated olefin unit. In this case, the weather resistance of the copolymer is improved.
Preferably, in the present invention, the acyclic unconjugated olefin unit is composed of only an ethylene unit. In this case, the acyclic unconjugated olefin compound from which the acyclic unconjugated olefin unit is derived is easily obtained, and therefore the production cost of the copolymer can be reduced.
In another preferred example of the copolymer of the present invention, the conjugated diene unit includes a 1, 3-butadiene unit and/or an isoprene unit. In this case, the conjugated diene compound from which the conjugated diene unit is derived is easily obtained, and therefore the production cost of the copolymer can be reduced.
In yet another preferred embodiment of the copolymer of the present invention, the conjugated diene unit includes only a 1, 3-butadiene unit. In this case, the conjugated diene compound from which the conjugated diene unit is derived is more easily obtained, and therefore the production cost of the copolymer can be further reduced as compared with other cases.
In still another preferred example of the copolymer of the present invention, the aromatic vinyl unit includes a styrene unit. In this case, an aromatic vinyl compound from which an aromatic vinyl unit is derived is easily obtained, and therefore the production cost of the copolymer can be reduced.
In still another preferred example of the copolymer of the present invention, the content of the non-conjugated olefin unit is in the range of 40 to 97 mol%, the content of the conjugated diene unit is in the range of 1 to 50 mol%, and the content of the aromatic vinyl unit is in the range of 2 to 35 mol%. In this case, the abrasion resistance and crack growth resistance of the copolymer are further improved and also the weather resistance thereof is improved.
The first production method of the copolymer of the present invention is a production method of a copolymer containing at least a non-conjugated olefin unit and a conjugated diene unit, wherein the method comprises the steps of:
curing the catalyst composition; and is
Copolymerizing at least a non-conjugated olefin compound and a conjugated diene compound in the presence of the thus-matured catalyst composition, the catalyst composition comprising:
a rare earth element-containing compound (A) containing a rare earth element compound or a reaction product resulting from a reaction between the rare earth element compound and a Lewis base;
at least one compound selected from the group consisting of an organometallic compound (B) represented by the following general formula (I), an ionic compound (C), and a halogen compound (D):
YR1 aR2 bR3 c…(I)
(in the general formula (I), Y represents a metal selected from the group consisting of
at least one compound (E) selected from the group consisting of a non-conjugated olefin compound and a conjugated diene compound.
According to the first production method of the copolymer of the present invention described above, a copolymer can be obtained which is reduced in heat generation in a low strain region and exhibits good processability while having excellent wear resistance and crack growth resistance.
A second production method of a copolymer of the present invention is a production method of a copolymer containing at least a non-conjugated olefin unit and a conjugated diene unit, the method including a step of copolymerizing at least a non-conjugated olefin compound and a conjugated diene compound in the presence of a catalyst composition including:
a rare earth element-containing compound (A) containing a rare earth element compound or a reaction product resulting from a reaction between the rare earth element compound and a Lewis base;
at least one compound selected from the group consisting of an organometallic compound (B) represented by the following general formula (I), an ionic compound (C), and a halogen compound (D):
YR1 aR2 bR3 c…(I)
(in the general formula (I), Y represents a metal selected from the group consisting of
at least one compound (E') selected from the group consisting of a non-conjugated olefin compound and a conjugated diene compound, the non-conjugated olefin compound and the conjugated diene compound being different in kind from the non-conjugated olefin compound and the conjugated diene compound copolymerized in the copolymerization step.
According to the second production method of the copolymer of the present invention described above, a copolymer can be obtained which is reduced in heat generation in a low strain region and exhibits good processability while having excellent wear resistance and crack growth resistance.
In a preferred example of the first/second production method of a copolymer of the present invention, the copolymer further contains an aromatic vinyl unit, and the copolymerization step includes copolymerizing the non-conjugated olefin compound, the conjugated diene compound, and an aromatic vinyl compound. In this case, the chain length of the non-conjugated olefin unit can be easily shortened.
In still another preferred example of the first/second production method of the copolymer of the present invention, the content of the non-conjugated olefin unit of the copolymer is in the range of 40 to 97 mol%, the content of the conjugated diene unit is in the range of 1 to 50 mol%, and the content of the aromatic vinyl unit is in the range of 2 to 35 mol%. In this case, the abrasion resistance and crack growth resistance of the resulting copolymer are further improved and also the weather resistance thereof is improved.
In the first/second production method of a copolymer of the present invention, the catalyst composition may further comprise aluminoxane (F). In this case, a desired copolymer can be easily obtained.
In still another preferred example of the first/second production method of a copolymer of the present invention, the compound (E) or the compound (E') is a non-conjugated olefin compound having three or more carbon atoms. In this case, the crystallinity of the resulting copolymer derived from the non-conjugated olefin unit in the temperature range of 100 ℃ to 150 ℃ as measured by DSC can be reduced.
In still another preferred example of the first/second production method of a copolymer of the present invention, the compound (E) or the compound (E') is a cyclic nonconjugated olefin compound. In this case, the crystallinity of the resulting copolymer derived from the non-conjugated olefin unit in the temperature range of 100 ℃ to 150 ℃ as measured by DSC can be reduced.
In still another preferred example of the first/second production method of a copolymer of the present invention, the compound (E) or the compound (E') is at least one selected from the group consisting of norbornene, 1, 3-butadiene and dicyclopentadiene. In this case, the crystallinity of the resulting copolymer derived from the non-conjugated olefin unit in the temperature range of 100 ℃ to 150 ℃ as measured by DSC can be reduced.
The rubber composition of the present invention is characterized by containing the above copolymer. The rubber composition of the present invention having high wear resistance and high crack growth resistance can reduce the rolling resistance of a tire when applied to the tire.
The tire of the present invention is characterized by using the above rubber composition. The tire of the present invention having high wear resistance and high crack growth resistance exhibits low rolling resistance.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, it is possible to provide a copolymer which is reduced in heat generation in a low strain region and exhibits good processability while having excellent wear resistance and crack growth resistance.
Further, according to the present invention, it is possible to provide a method for producing a copolymer capable of obtaining a copolymer which is reduced in heat generation property in a low strain region and exhibits good processability, while having excellent wear resistance and crack growth resistance.
Still further, according to the present invention, it is possible to provide a rubber composition capable of reducing the rolling resistance of a tire while having high wear resistance and high crack growth resistance, and a tire exhibiting low rolling resistance while having high wear resistance and high crack growth resistance.
Drawings
In the drawings, wherein:
FIG. 1 is a DSC of copolymer a;
FIG. 2 is a DSC of copolymer A;
FIG. 3 is a DSC of copolymer B; and
FIG. 4 is a DSC of copolymer C.
Detailed Description
The copolymer, the method for producing the copolymer, the rubber composition, and the tire of the present invention will be described in detail below based on embodiments thereof.
< copolymer >
The copolymer of the present invention is a copolymer containing at least a non-conjugated olefin unit and a conjugated diene unit, wherein the content of the non-conjugated olefin unit therein is 40 mol% or more; and a crystallinity originating from the non-conjugated olefin unit in a temperature range of 100 ℃ to 150 ℃ as measured by a Differential Scanning Calorimeter (DSC) is 4.0% or less.
The copolymer of the present invention comprises a non-conjugated olefin unit, whereby when the copolymer is significantly deformed, a crystal component derived from the non-conjugated olefin unit collapses, and thus the copolymer can effectively dissipate energy. Further, the copolymer of the present invention having a content of the non-conjugated olefin unit of not less than 40 mol% exhibits a high energy dissipation capability in a high strain region. Still further, the copolymer of the present invention, which thus has high energy dissipation capability in a high strain region, can suppress abrasion and crack growth due to significant deformation by dissipating energy.
The endothermic peak in the range of 100 ℃ to 150 ℃ determined by DSC measurement is derived from non-conjugated olefin units having a relatively long chain length. In this aspect, the copolymer of the present invention contains a relatively large content of a component of the non-conjugated olefin unit having a relatively short chain length, because the crystallinity derived from the non-conjugated olefin unit in the range of 100 ℃ to 150 ℃ as measured by DSC of the copolymer is 4.0% or less. The abundance of the non-conjugated olefin unit having a relatively long chain length indicates the abundance of the crystalline component (hard portion) in the copolymer, that is, hysteresis loss is easily generated even at a low strain therein. Further, when the copolymer is blended into a rubber composition, the crystalline component or hard portion of the copolymer deteriorates processability in kneading of the rubber composition. In this aspect, the copolymer of the present invention, which contains a relatively large content of a non-conjugated olefin unit component having a relatively short chain length, exhibits low loss hysteresis when a low strain is applied, and therefore heat generation property is reduced in a low strain region, and also exhibits good processability in compounding of a rubber composition when the copolymer is blended into the rubber composition.
Therefore, the copolymer of the present invention has reduced heat generation in a low strain region and exhibits good processability while having excellent wear resistance and crack growth resistance.
In the copolymer of the present invention, the crystallinity derived from the non-conjugated olefin units thereof in the temperature range of 100 ℃ to 150 ℃ as measured by a Differential Scanning Calorimeter (DSC) is 4.0% or less, preferably 2.5% or less, and more preferably 1.0% or less. The lower limit of the crystallinity is not particularly limited, and may be 0%. The smaller the crystallinity derived from the non-conjugated olefin unit in the range of 100 to 150 ℃ as measured by DSC represents the shorter the chain length of the non-conjugated olefin unit, and therefore the more the heat generation property decreases in the low strain region, and the better the processability in the kneading step when the copolymer is blended into the rubber composition.
In the present invention, "crystallinity" means a value measured according to the method described in examples.
The copolymer of the present invention containing at least a non-conjugated olefin unit and a conjugated diene unit may be composed of only a non-conjugated olefin unit and a conjugated diene unit or may further contain other monomer units.
The non-conjugated olefin unit is a structural unit derived from a non-conjugated olefin compound as a monomer. The non-conjugated olefin compound means an aliphatic unsaturated hydrocarbon compound having at least one carbon-carbon double bond. The kind of the non-conjugated olefin compound is not particularly limited, but the non-conjugated olefin compound preferably has 2 to 10 carbon atoms. Specific examples of the above-mentioned non-conjugated olefin compounds include: α -olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene, etc.; heteroatom-substituted olefinic compounds such as vinyl pivalate, 1-phenylthioethylene, N-vinylpyrrolidone; and the like. A single species or a combination of two or more species in these examples may be used as the non-conjugated olefin compound. The non-conjugated olefin compound as a monomer of the copolymer is preferably a non-cyclic non-conjugated olefin compound from the viewpoint of improving the weather resistance of a rubber composition, a tire, or the like using the obtained copolymer. The acyclic nonconjugated olefin compound is preferably an α -olefin, and particularly preferably ethylene. An acyclic nonconjugated olefin compound such as an α -olefin, particularly ethylene, has a double bond at the α -position of the olefin, whereby the compound can be efficiently polymerized with a conjugated diene compound described below, and when it is used for a copolymer, the weather resistance of a rubber composition and a tire using the copolymer can be further improved.
In the copolymer of the present invention, the non-conjugated olefin unit is preferably a non-cyclic non-conjugated olefin unit. When the non-conjugated olefin unit is a non-cyclic non-conjugated olefin unit, the weather resistance of a rubber composition and a tire using the resulting copolymer is improved.
In the copolymer of the present invention, it is particularly preferred that the non-conjugated olefin unit is composed of only ethylene units. In the case where the non-conjugated olefin unit is composed of only an ethylene unit, a non-conjugated olefin compound from which the non-conjugated olefin unit is derived, that is, ethylene, is easily obtained, and therefore the production cost of the copolymer can be reduced.
In the copolymer of the present invention, the content of the non-conjugated olefin unit is not less than 40 mol%, preferably not less than 45 mol%, more preferably not less than 55 mol%, particularly preferably not less than 60 mol%, and preferably not more than 97 mol%, more preferably not more than 95 mol%, still more preferably not more than 90 mol%. When the content of the non-conjugated olefin unit is 40 mol% or more, the copolymer exhibits high energy dissipation ability in its high strain region. Further, in this case, the content of the conjugated diene unit or the aromatic vinyl unit described below is thus reduced, thereby improving the weather resistance and/or fracture resistance (particularly, breaking strength (Tb)) of the copolymer at high temperatures. When the content of the non-conjugated olefin unit is 97 mol% or less, the content of the conjugated diene unit or the aromatic vinyl unit is thereby increased, thereby improving the fracture resistance (particularly, elongation at break (Eb)) of the copolymer at high temperature. The content of the non-conjugated olefin unit is preferably in the range of 40 to 97 mol%, more preferably in the range of 45 to 95 mol%, and further more preferably in the range of 55 to 90 mol% of the whole copolymer.
The conjugated diene unit is a structural unit derived from a conjugated diene compound as a monomer. Although the kind of the conjugated diene compound is not particularly limited, the conjugated diene compound preferably has 4 to 8 carbon atoms. Specific examples of the conjugated diene compound include 1, 3-butadiene, isoprene, 1, 3-pentadiene, and 2, 3-dimethyl-1, 3-butadiene, and the like. From the viewpoint of availability, 1, 3-butadiene and isoprene are preferable among these examples, and 1, 3-butadiene is particularly preferable. A single species or a combination of two or more species in these examples may be used as the conjugated diene compound.
In the copolymer of the present invention, the conjugated diene unit preferably includes a 1, 3-butadiene unit and/or an isoprene unit. When the conjugated diene unit includes a 1, 3-butadiene unit and/or an isoprene unit, a conjugated diene compound from which the conjugated diene unit is derived (i.e., 1, 3-butadiene, isoprene) is easily obtained, and thus the production cost of the copolymer can be reduced.
Further, in the copolymer of the present invention, it is particularly preferable that the conjugated diene unit is composed of only 1, 3-butadiene units. When the conjugated diene unit is composed of only 1, 3-butadiene units, the conjugated diene compound from which the conjugated diene unit is derived (i.e., 1, 3-butadiene) is easily obtained, and therefore the production cost of the copolymer can be reduced.
In the copolymer of the present invention, the content of the conjugated diene unit is preferably not less than 1 mol%, more preferably not less than 3 mol%, and preferably not more than 50 mol%, more preferably not more than 40 mol%, further more preferably not more than 30 mol%, still further more preferably not more than 25 mol%, particularly preferably not more than 15 mol%. The content of the conjugated diene unit is preferably 1 mol% or more, because this remarkably promotes vulcanization of the copolymer and a rubber composition and a rubber article excellent in elongation can be obtained. The content of the conjugated diene unit of 50 mol% or less realizes excellent weather resistance. The content of the conjugated diene is preferably in the range of 1 to 50 mol%, more preferably in the range of 3 to 40 mol% of the whole copolymer.
Preferably, the copolymer of the present invention further contains an aromatic vinyl unit in addition to the non-conjugated olefin unit and the conjugated diene unit. When the copolymer contains an aromatic vinyl unit, the chain length of the non-conjugated olefin unit can be shortened more easily than in other cases.
The aromatic vinyl unit is a structural unit derived from an aromatic vinyl compound as a monomer. "aromatic vinyl compound" means an aromatic compound that has been substituted with at least a vinyl group. Although the kind of the aromatic vinyl compound is not particularly limited, the aromatic vinyl compound preferably has 8 to 10 carbon atoms. Examples of the aromatic vinyl compound include styrene, α -methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o, p-dimethylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene and the like. Among these examples, styrene is preferred from the viewpoint of easy availability. A single species or a combination of two or more species in the examples may be used as the aromatic vinyl compound.
The copolymer of the present invention preferably includes a styrene unit as the aromatic vinyl unit. When the copolymer includes a styrene unit, an aromatic vinyl compound (i.e., styrene) from which an aromatic vinyl unit is derived is easily obtained, and thus the production cost of the copolymer can be reduced.
In the copolymer of the present invention, the content of the aromatic vinyl unit may be 0 mol% or more, but is preferably 2 mol% or more, more preferably 3 mol% or more, and is preferably 35 mol% or less, more preferably 30 mol% or less, and still more preferably 25 mol% or less. The content of the aromatic vinyl unit of not less than 2 mol% improves the fracture resistance at high temperatures. When the content of the aromatic vinyl unit is 35 mol% or less, the effect caused by the non-conjugated olefin unit and the conjugated diene unit is remarkable. The content of the aromatic vinyl unit is preferably in the range of 2 to 35 mol%, more preferably in the range of 3 to 30 mol%, and still more preferably in the range of 3 to 25 mol% of the whole copolymer.
It is preferable that in the copolymer of the present invention, the content of the non-conjugated olefin unit is in the range of 40 to 97 mol%, the content of the conjugated diene unit is in the range of 1 to 50 mol%, and the content of the aromatic vinyl unit is in the range of 2 to 35 mol%. In this case, the wear resistance and crack growth resistance of the rubber composition having the copolymer blended therein are further improved, and also the weather resistance thereof is improved.
The weight average molecular weight (Mw) of the copolymer of the present invention in terms of polystyrene is preferably in the range of 10,000 to 10,000,000, more preferably in the range of 100,000 to 9,000,000, and further more preferably in the range of 150,000 to 8,000,000. The weight average molecular weight (Mw) of the copolymer of 10,000 or more ensures satisfactory mechanical strength of the rubber composition, and the Mw of the copolymer of 10,000,000 or less ensures good processability of the rubber composition.
Further, the number average molecular weight (Mn) of the copolymer of the present invention in terms of polystyrene is preferably in the range of 10,000 to 10,000,000, more preferably in the range of 50,000 to 9,000,000, and still more preferably in the range of 100,000 to 8,000,000. The number average molecular weight (Mn) of the copolymer of 10,000 or more ensures satisfactory mechanical strength of the rubber composition, and the Mn of the copolymer of 10,000,000 or less ensures good processability of the rubber composition.
Still further, the molecular weight distribution [ Mw/Mn (weight average molecular weight/number average molecular weight) ] of the copolymer of the present invention is preferably in the range of 1.00 to 4.00, more preferably in the range of 1.50 to 3.50, and still more preferably in the range of 1.80 to 3.00. By setting the molecular weight distribution of the copolymer to 4.00 or less, the physical properties of the copolymer can be satisfactorily made uniform.
The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw/Mn) with respect to polystyrene as a standard substance were determined by Gel Permeation Chromatography (GPC).
In the copolymer of the present invention, its melting point as measured by a Differential Scanning Calorimeter (DSC) is preferably in the range of 30 to 130 ℃ and more preferably in the range of 30 to 110 ℃. When the melting point of the copolymer is 30 ℃ or higher, the crystallinity of the copolymer increases, and therefore the abrasion resistance and the crack growth resistance thereof are further improved. When the melting point of the copolymer is 130 ℃ or lower, the processability is improved.
The melting point represents a value measured by using a differential scanning calorimeter according to JIS K7121-1987 in the present invention.
In the copolymer of the present invention, the endothermic energy at the endothermic peak thereof in the range of 0 ℃ to 120 ℃ as measured by a Differential Scanning Calorimeter (DSC) is preferably in the range of 10J/g to 150J/g, and more preferably in the range of 30J/g to 120J/g. When the endothermic energy at the endothermic peak of the copolymer is 10J/g or more, the crystallinity of the copolymer is sufficiently high and the abrasion resistance and the crack growth resistance of the copolymer are further improved. When the endothermic energy at the endothermic peak of the copolymer is 150J/g or less, the processability of the copolymer is improved.
In the present invention, "endothermic energy at endothermic peak" means a value of endothermic energy at endothermic peak measured in the range of 0 ℃ to 120 ℃ by using a differential scanning calorimeter when a sample is heated from-150 ℃ to 150 ℃ at a temperature rising rate of 10 ℃/minute in the first run according to JIS K7121-1987.
In the copolymer of the present invention, the glass transition temperature (Tg) as measured by a Differential Scanning Calorimeter (DSC) is preferably 0 ℃ or less, and more preferably in the range of-100 ℃ to-10 ℃. When the glass transition temperature of the copolymer is 0 ℃ or lower, the processability is improved.
"glass transition temperature" means a value measured by using a differential scanning calorimeter according to JIS K7121-1987 in the present invention.
It is preferable that the main chain of the copolymer of the present invention is composed of only a non-cyclic structure, because the crack growth resistance of the copolymer can be further improved. NMR was used as the primary measure to determine whether the backbone of the copolymer consists only of acyclic structures. Specifically, when a peak derived from a cyclic structure present in the main chain (for example, any peak appearing in the range of 10ppm to 24ppm in the case of a three-membered ring structure, a four-membered ring structure and a five-membered ring structure) is not observed, the result indicates that the main chain of the copolymer is composed of only a non-cyclic structure.
< method for producing copolymer >
The copolymer of the present invention described above can be obtained by a method (first production method of the copolymer of the present invention), wherein the method comprises the steps of: curing the catalyst composition; and copolymerizing at least a non-conjugated olefin compound and a conjugated diene compound in the presence of the thus-matured catalyst composition comprising
A rare earth element-containing compound (A) containing a rare earth element compound or a reaction product resulting from a reaction between a rare earth element compound and a Lewis base;
at least one compound selected from the group consisting of an organometallic compound (B) represented by the following general formula (I), an ionic compound (C), and a halogen compound (D):
YR1 aR2 bR3 c…(I)
(in the general formula (I), Y represents a metal selected from the group consisting of
at least one compound (E) selected from the group consisting of a non-conjugated olefin compound and a conjugated diene compound.
According to the above-mentioned first method, the compound (E) is added to the catalyst composition in advance, and then the catalyst composition is aged, so that the compound (E) is introduced into the catalyst composition in a sufficient manner, whereby it is possible to suppress the introduction of the compound (E) into the copolymer and thereby reduce the endothermic energy of the resulting copolymer at the endothermic peak in the temperature range of 100 ℃ to 150 ℃ as determined by DSC measurement, thereby successfully reducing the crystallinity derived from the nonconjugated olefin unit in the range of 100 ℃ to 150 ℃ as measured by DSC.
Therefore, a copolymer, which is reduced in heat generation in a low strain region and exhibits good processability while having excellent wear resistance and crack growth resistance, can be obtained by the above-described first production method of the copolymer of the present invention.
Alternatively, the above-mentioned copolymer of the present invention may be obtained by a method (second production method of the copolymer of the present invention) comprising a step of copolymerizing at least a non-conjugated olefin compound and a conjugated diene compound in the presence of a catalyst composition comprising:
a rare earth element-containing compound (A) containing a rare earth element compound or a reaction product resulting from a reaction between a rare earth element compound and a Lewis base;
at least one compound selected from the group consisting of an organometallic compound (B) represented by the following general formula (I), an ionic compound (C), and a halogen compound (D):
YR1 aR2 bR3 c…(I)
(in the general formula (I), Y represents a metal selected from the group consisting of
and at least one compound (E') selected from the group consisting of a non-conjugated olefin compound and a conjugated diene compound, the non-conjugated olefin compound and the conjugated diene compound being different in kind from the non-conjugated olefin compound and the conjugated diene compound copolymerized in the copolymerization step.
It is possible to reduce the endothermic energy at the endothermic peak in the range of 100 ℃ to 150 ℃ determined by DSC measurement of the copolymer thus produced, and to reduce the crystallinity derived from the non-conjugated olefin unit in the range of 100 ℃ to 150 ℃ measured by DSC by adding the compound (E') to the catalyst composition. In this respect, the compound (E ') selected from the group consisting of a non-conjugated olefin compound and a conjugated diene compound different in kind from the non-conjugated olefin compound and the conjugated diene compound copolymerized in the copolymerization step should be lower in reactivity to the polymerization reaction than the non-conjugated olefin compound and the conjugated diene compound used as monomers in the copolymerization step, so that the compound (E') is difficult to be incorporated into the resulting copolymer. Therefore, according to the above-mentioned second method, the endothermic energy at the endothermic peak in the range of 100 ℃ to 150 ℃ determined by DSC measurement of the resulting copolymer can be reduced without aging the catalyst composition.
Therefore, a copolymer, which is reduced in heat generation in a low strain region and exhibits good processability while having excellent wear resistance and crack growth resistance, can be obtained by the above-described second production method of the copolymer of the present invention.
In the case where the copolymer further contains an aromatic vinyl unit, a copolymer containing an aromatic vinyl unit can be produced by copolymerizing a non-conjugated olefin compound, a conjugated diene compound and an aromatic vinyl compound in the presence of the catalyst composition. By using an aromatic vinyl compound as a monomer, the chain length of the non-conjugated olefin unit can be shortened more easily.
The same definitions as described above and below in the < copolymer > section apply to the non-conjugated olefin compound and the conjugated diene compound used as monomers in the first/second production method of the above-described copolymer. Similarly, the same definitions as those described in the context of the < copolymer > moiety apply to the aromatic vinyl compound that can be used in the first/second production method of the above-described copolymer.
The rare earth element-containing component (a) used in the catalyst composition includes a rare earth element compound or a reaction product resulting from the reaction of a rare earth element compound and a lewis base. More specifically, the rare earth element-containing component (a) includes: a rare earth element compound or a reaction product resulting from a reaction of the rare earth element compound and a lewis base, the compound/reaction product having a bond between the rare earth element and carbon (the compound/reaction product may be hereinafter referred to as "component (a-1)"); and a rare earth element compound or a reaction product resulting from the reaction of the rare earth element compound and a lewis base, the compound/reaction product having no bond between the rare earth element and carbon (the compound/reaction product is hereinafter sometimes referred to as "component (a-2)").
Examples of the component (A-1) include:
a metallocene complex represented by the following general formula (II):
(in the formula (II), M represents a lanthanoid, scandium, or yttrium; CpREach independently represents an unsubstituted/substituted indenyl group; ra～RfEach independently represents C1-3An alkyl group or a hydrogen atom; l represents a neutral lewis base; and w represents an integer in the range of 0 to 3);
a metallocene complex represented by the following general formula (III)
(in the formula (III), M represents a lanthanoid, scandium, or yttrium; CpREach independently represents an unsubstituted/substituted indenyl group; x' represents a hydrogen atom, a halogen atom, an alkoxy group, a mercapto group, an amino group, a silyl group, or C1-20A monovalent hydrocarbon group; l represents a neutral lewis base; and w represents an integer in the range of 0 to 3); and
a half-metallocene cationic complex represented by the following general formula (IV):
(in the formula (IV), M represents a lanthanoid, scandium, or yttrium; CpR’Represents an unsubstituted/substituted cyclopentadienyl group, an unsubstituted/substituted indenyl group, or an unsubstituted/substituted fluorenyl group; x represents a hydrogen atom, a halogen atom, an alkoxy group, a mercapto group, an amino group, a silyl group, or C1-20A monovalent hydrocarbon group; l represents a neutral lewis base; w represents an integer in the range of 0 to 3); and [ B]-Represents a non-coordinating anion).
In the metallocene complexes represented by the general formulae (II) and (III), respectively, CpRIs unsubstituted/substituted indenyl. Cp having indenyl ring as basic skeletonRCan be represented as C9H7-XRXOr C9H11-XRXWherein X represents an integer in the range of 0 to 7 or 0 to 11; r preferably each independently represents a hydrocarbyl group or a metalloid group; the number of carbon atoms of the hydrocarbon group is preferably in the range of 1 to 20, more preferably in the range of 1 to 10, and still more preferably in the range of 1 to 8. Specifically, preferred examples of the hydrocarbon group include methyl, ethyl, phenyl, benzyl and the like. Examples of the metalloid group include germylge, stannyl Sn, and silyl Si. The metalloid group preferably includes a hydrocarbon group defined in the same manner as the above-mentioned hydrocarbon group. Specific examples of the metalloid group include trimethylsilaneAnd the like. Specific examples of the substituted indenyl group include 2-phenylindenyl and 2-methylindenyl, etc. Two Cp in the general formula (II)RMay be of the same kind or of different kinds. Two Cp in the general formula (III)RMay be of the same kind or of different kinds.
In the half-metallocene cation complex represented by the general formula (IV), CpR’Is unsubstituted/substituted cyclopentadienyl, unsubstituted/substituted indenyl, or unsubstituted/substituted fluorenyl. Among these examples, unsubstituted/substituted indenyl is preferred as CpR’。
In the general formula (IV), Cp having a cyclopentadienyl ring as a basic skeletonR’Is represented as C5H5-XRXWherein X is an integer in the range of 0-5; r preferably each independently represents a hydrocarbyl group or a metalloid group; the number of carbon atoms of the hydrocarbon group is preferably in the range of 1 to 20, more preferably in the range of 1 to 10, and still more preferably in the range of 1 to 8. Specifically, preferred examples of the hydrocarbon group include methyl, ethyl, phenyl, benzyl and the like. Examples of the metalloid group include germylge, stannyl Sn, and silyl Si. The metalloid group preferably includes a hydrocarbon group defined in the same manner as the above-mentioned hydrocarbon group. Specific examples of the metalloid group include trimethylsilyl and the like. Cp having cyclopentadienyl ring as basic skeletonR’Specific examples of (a) include compounds represented by the following structural formula:
(in these structural formulae, R represents a hydrogen atom, a methyl group or an ethyl group).
In the general formula (IV), Cp having an indenyl ring as a basic skeletonR’And preferred examples thereof with Cp in the general formula (II)RAnd Cp in the general formula (III)RDefined in the same manner.
In the general formula (IV), Cp having a fluorenyl ring as a basic skeletonR’Is represented as C13H9-XRXOr C13H17-XRXWherein X is an integer in the range of 0 to 9 or 0 to 17; r preferably each independently represents a hydrocarbyl group or a metalloid group; the number of carbon atoms of the hydrocarbon group is preferably in the range of 1 to 20, more preferably in the range of 1 to 10, and still more preferably in the range of 1 to 8. Specifically, preferred examples of the hydrocarbon group include methyl, ethyl, phenyl, benzyl and the like. Examples of the metalloid group include germylge, stannyl Sn, and silyl Si. The metalloid group preferably includes a hydrocarbon group defined in the same manner as the above-mentioned hydrocarbon group. Specific examples of the metalloid group include trimethylsilyl and the like.
The central metal M in each of the general formulae (II), (III) and (IV) is a lanthanide, scandium or yttrium. The lanthanide series of elements includes the 15 elements of the periodic table having atomic numbers 57-71, any one of which is acceptable. Preferred examples of the central metal M include samarium Sm, neodymium Nd, praseodymium Pr, gadolinium Gd, cerium Ce, holmium Ho, scandium Sc, and yttrium Y.
The metallocene complex represented by the general formula (II) includes a silylamino ligand [ -N (SiR)3)2]. The R group included in the silylamine ligand (i.e., R in the general formula (II))a～Rf) Each independently represents C1-3Alkyl groups or hydrogen atoms. Preferably, R isa～RfAt least one of them is a hydrogen atom. When R isa～RfWhen at least one of them is a hydrogen atom, since steric hindrance around the silicon atom is relatively small, the catalyst can be easily synthesized, and the non-conjugated olefin compound and the aromatic vinyl compound can be easily introduced. For similar reasons, it is more preferred that Ra～RcAt least one of which is a hydrogen atom and Rd～RfAt least one of them is a hydrogen atom. Methyl is preferred as alkyl.
The metallocene complex represented by the general formula (III) includes a silyl ligand [ -SiX'3]. Silyl ligand [ -SiX'3]The X' group included and preferred examples thereof are defined in the same manner as the X group in the following general formula (IV).
In the general formula (IV), X is selected from a hydrogen atom, a halogen atom, an alkaneOxy, mercapto, amino, silyl, and C1-20Monovalent hydrocarbon radicals. Acceptable examples of the halogen atom represented by X in the general formula (IV) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Preferably a chlorine atom or a bromine atom.
In the general formula (IV), examples of the alkoxy group represented by X include: aliphatic alkoxy groups such as methoxy, ethoxy, propoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy and the like; and aryloxy groups such as phenoxy group, 2, 6-di-t-butylphenoxy group, 2, 6-diisopropylphenoxy group, 2, 6-dineopentylphenoxy group, 2-t-butyl-6-isopropylphenoxy group, 2-t-butyl-6-neopentylphenoxy group, 2-isopropyl-6-neopentylphenoxy group and the like. Of these examples, 2, 6-di-tert-butylphenoxy is preferred as alkoxy group.
In the general formula (IV), examples of the hydrocarbylthio group represented by X include: aliphatic hydrocarbylthio groups such as thiomethoxy, thioethoxy, thiopropoxy, thio-n-butoxy, thio-isobutoxy, thio-sec-butoxy, and thio-tert-butoxy, and the like; and arylhydrocarbylthio groups such as thiophenoxy, 2, 6-di-tert-butylthiophenoxy, 2, 6-diisopropylthiophenoxy, 2, 6-dineopentylthiophenoxy, 2-tert-butyl-6-isopropylthiophenoxy, 2-tert-butyl-6-thioneopentylphenoxy, 2-isopropyl-6-thioneopentylphenoxy, and 2,4, 6-triisopropylthiophenoxy and the like. Of these examples, 2,4, 6-triisopropylthiophenoxy is preferred as the hydrocarbylthio group.
In the general formula (IV), examples of the amino group represented by X include: aliphatic amino groups such as dimethylamino group, diethylamino group, diisopropylamino group, and the like; arylamino groups such as phenylamino, 2, 6-di-tert-butylphenyl amino, 2, 6-diisopropylphenylamino, 2, 6-dineopentylphenylamino, 2-tert-butyl-6-isopropylphenylamino, 2-tert-butyl-6-neopentylphenylamino, 2-isopropyl-6-neopentylphenylamino, and 2,4, 6-tri-tert-butylphenyl amino, etc.; bis (trialkylsilyl) amino groups such as bis (trimethylsilyl) amino; and the like. Among these examples, a bis (trimethylsilyl) amino group is preferable as the amino group.
In the general formula (IV), examples of the silyl group represented by X include a trimethylsilyl group, a tris (trimethylsilyl) silyl group, a bis (trimethylsilyl) methylsilyl group, a trimethylsilyl (dimethyl) silyl group, a (triisopropylsilyl) bis (trimethylsilyl) silyl group and the like. Among these examples, a tris (trimethylsilyl) silyl group is preferable as the silyl group.
In the general formula (IV), C represented by X1-20Specific examples of the monovalent hydrocarbon group include: straight/branched aliphatic hydrocarbon groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, neopentyl, hexyl and octyl; aromatic hydrocarbon groups such as phenyl, tolyl, and naphthyl; aralkyl groups such as benzyl; a hydrocarbon group containing a silicon atom such as a trimethylsilylmethyl group, a bis (trimethylsilyl) methyl group; and the like. Among these examples, methyl, ethyl, isobutyl, and trimethylsilylmethyl and the like are preferred as C1-20A monovalent hydrocarbon group.
In the general formula (IV), bistrimethylsilylamino or C1-20Monovalent hydrocarbon groups are preferred as X.
In the general formula (IV), from [ B]-Examples of non-coordinating anions that are represented include tetravalent boron anions. Specific examples of the tetravalent boron anion include tetraphenyl borate, tetrakis (monofluorophenyl) borate, tetrakis (difluorophenyl) borate, tetrakis (trifluorophenyl) borate, tetrakis (tetrafluorophenyl) borate, tetrakis (pentafluorophenyl) borate, tetrakis (tetrafluoromethylphenyl) borate, tetrakis (tolyl) borate, tetraxylyl borate, triphenyl (pentafluorophenyl) borate, [ tris (pentafluorophenyl) phenyl ] borate]Borate, and tridecyl-7, 8-dicarbonylundecanoborate, and the like. Of these examples, tetrakis (pentafluorophenyl) borate is preferred as the tetravalent boron anion.
The metallocene complex represented by the general formulae (II) and (III), respectively, and the half-metallocene cationic complex represented by the general formula (IV) each further include 0 to 3, preferably 0 to 1, neutral Lewis bases L. Examples of the neutral Lewis base L include tetrahydrofuran, diethyl ether, dimethylaniline, trimethylphosphine, lithium chloride, neutral olefins, and neutral diolefins and the like. When the complex includes a plurality of neutral lewis bases L, the neutral lewis bases L may be the same kind or different kinds.
The metallocene complex represented by the general formulae (II) and (III), respectively, and the half-metallocene cationic complex represented by the general formula (IV) may each exist as any one of a monomer, a dimer, or other kinds of multimers.
The metallocene complex represented by the general formula (II) can be obtained by, for example, reacting a lanthanoid trihalide, scandium trihalide, or yttrium trihalide with an indenyl salt (such as an indenyl potassium salt or a lithium salt) and a bis (trialkylsilyl) amine salt (such as a potassium salt or a lithium salt of bis (trialkylsilyl) amine) in a solvent. The reaction temperature may be set around room temperature, which allows for manufacturing under mild conditions. The reaction time may be set as desired, and is usually in the range of several hours to several days. The kind of the reaction solvent is not limited, but a solvent capable of dissolving the raw materials and the reaction product is preferable. For example, toluene may be used. Examples of the reaction for obtaining the metallocene complex represented by the general formula (II) are shown below.
(in the above reaction example, X "represents a halide.)
The metallocene complex represented by the general formula (III) can be obtained by, for example, reacting a lanthanoid trihalide, scandium trihalide, or yttrium trihalide with an indenyl salt (e.g., indenyl potassium salt or lithium salt) and a silyl salt (e.g., silyl potassium salt or lithium salt) in a solvent. The reaction temperature may be set around room temperature, which allows for manufacturing under mild conditions. The reaction time may be set as desired, and is usually in the range of several hours to several days. The kind of the reaction solvent is not limited, but a solvent capable of dissolving the raw materials and the reaction product is preferable. For example, toluene may be used. Examples of the reaction for obtaining the metallocene complex represented by the general formula (III) are shown below.
(in the above reaction example, X "represents a halide.)
The half-metallocene cation complex represented by the general formula (IV) can be obtained by, for example, the reaction shown below.
In the compound represented by the general formula (V), M represents a lanthanoid, scandium, or yttrium; cpREach independently represents an unsubstituted/substituted cyclopentadienyl group, an unsubstituted/substituted indenyl group, or an unsubstituted/substituted fluorenyl group; and X represents a hydrogen atom, a halogen atom, an alkoxy group, a mercapto group, an amino group, a silyl group, or C1-20A monovalent hydrocarbon group. L represents a neutral Lewis base, and w represents an integer in the range of 0 to 3. In the general formula [ A]+[B]-Among the ionic compounds represented by (A)]+Represents a cation, [ B ]]-Represents a non-coordinating anion.
From [ A ]]+Examples of cations represented include carbonium cations, oxonium cations, amine cations, phosphonium cations, cycloheptatriene cations, and transition metal-containing ferrocenium cations, among others. Examples of carbonium cations include trisubstituted carbonium cations such as triphenylcarbonium cation, tris (substituted phenyl) carbonium cation, and the like. Specific examples of the tri (substituted phenyl) carbonium cation include a tri (methylphenyl) carbonium cation. Examples of amine cations include: trialkylammonium cations such as trimethylammonium cation, triethylammonium cation, tripropylammonium cation, and tributylammonium cation; n, N-dialkylanilinium cations such as N, N-dimethylanilinium cation, N-diethylanilinium cation and N, N-2,4, 6-pentamethylanilinium cation; dialkylammonium cations such as diisopropylammonium cation and dicyclohexylammonium cation; and the like. Examples of phosphonium cations include triarylphosphonium cations such as triphenylphosphonium cation, tris (methylphenyl) phosphonium cation, tris (dimethylphenyl) phosphonium cation, and the like. Among these, N-dialkylanilinium cations or carbonium cations are preferred,N, N-dialkylanilinium cations are particularly preferred as [ A ]]+。
The compound represented by the general formula [ A ] used in the above reaction]+[B]-The ionic compound represented is, for example, a compound obtained by combining a non-coordinating anion and a cation respectively selected from the above examples, and is preferably N, N-dimethylaniline tetrakis (pentafluorophenyl) borate, triphenylcarbeniumtetrakis (pentafluorophenyl) borate, or the like. When compared in mol, from the formula [ A ]]+[B]-The amount of the ionic compound added to the metallocene complex is preferably 0.1 to 10 times, more preferably about 1 time the amount of the metallocene complex. In the case where the half-metallocene cationic complex represented by the general formula (IV) is used in the polymerization reaction, the half-metallocene cationic complex represented by the general formula (IV) may be directly supplied into the polymerization reaction system, or alternatively, the compound represented by the general formula (V) and the compound represented by the general formula [ A ] used in the above-mentioned reaction may be separately supplied in the polymerization reaction system]+[B]-The ionic compound forms a half-metallocene cation complex represented by the general formula (IV) in a polymerization reaction system. Further alternatively, it is possible to produce a polymer having a structure represented by the general formula [ A ] or the general formula [ III ] by using the metallocene complex represented by the general formula (II) or the general formula (III) in combination in the polymerization reaction system]+[B]-The ionic compound thus represented forms a half-metallocene cation complex represented by the general formula (IV) in the polymerization reaction system.
The structures of the metallocene complex represented by the general formula (II) or the general formula (III), respectively, and the half-metallocene cation complex represented by the general formula (IV) are each preferably determined by X-ray structural analysis.
Other examples of the component (A-1) include metallocene-based composite catalysts represented by the following formula (VI):
RaMXbQYb…(VI)
(in the formula (VI), R independently represents an unsubstituted/substituted indenyl group; M is coordinated to R; M represents a lanthanoid, scandium, or yttrium; and X independently represents C1-20A monovalent hydrocarbon group; m and Q coordinate to X mu; q represents an element of group 13 of the periodic table; y is each independentlyIs represented by ground C1-20A monovalent hydrocarbon group or a hydrogen atom; q coordinates to Y; and a-b-2).
Preferred examples of the metallocene-based composite catalyst represented by the formula (VI) include metallocene-based composite catalysts represented by the following formula (VII):
(in the formula (VII), M1Represents a lanthanide, scandium, or yttrium; cpREach independently represents an unsubstituted/substituted indenyl group; rAAnd RBEach independently represents C1-20A hydrocarbyl group; m1And Al and RAAnd RBMu coordination; and R isCAnd RDEach independently represents C1-20A hydrocarbon group or a hydrogen atom. )
The target copolymer can be efficiently produced by using the metallocene-based composite catalyst. Further, by using a metallocene-based composite catalyst, for example, a composite which has been prepared in advance in combination with an aluminum catalyst, the amount of aluminum alkyl used in the copolymer synthesis can be reduced or even eliminated. It should be noted in this regard that if a conventional catalyst system not using the above metallocene-based composite catalyst is employed, a large amount of aluminum alkyl is required during the copolymer synthesis. For example, in a conventional catalyst system in which the above-mentioned metallocene-based composite catalyst is not used, the aluminum alkyl must be used in an amount of at least 10 times the stoichiometric equivalent of the relevant metal catalyst. In contrast, in the case of using the above metallocene-based composite catalyst, an excellent catalytic effect was demonstrated by adding an amount of aluminum alkyl of about 5 times the stoichiometric equivalent of the metal catalyst.
In the metallocene-based composite catalyst, the metal M in the general formula (VI) is a lanthanoid, scandium, or yttrium. The lanthanide series of elements includes the 15 elements with atomic numbers 57-71, any one of which is acceptable. Preferred examples of the metal M include samarium Sm, neodymium Nd, praseodymium Pr, gadolinium Gd, cerium Ce, holmium Ho, scandium Sc, and yttrium Y.
In formula (VI), each R independently represents an unsubstituted/substituted indenyl group, and M is coordinated to R. Specific examples of substituted indenyl groups include 1,2, 3-trimethylindenyl, heptamethylindenyl, and 1,2,4,5,6, 7-hexamethylindenyl, and the like.
In formula (VI), Q represents an element of group 13 in the periodic table, and specific examples thereof include boron, aluminum, gallium, indium, thallium, and the like.
In the formula (VI), X represents C independently1-20A monovalent hydrocarbon group, and M and Q coordinate to X μ. C1-20Examples of monovalent hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl, and the like. The expression "M and Q are coordinated to X. mu. means that M and Q are coordinated to X in a cross-linked manner.
In formula (VI), Y independently represents C1-20A monovalent hydrocarbon group or a hydrogen atom, and Q is coordinated to Y. In this respect, C1-20Examples of monovalent hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl, and the like.
In formula (VII), the metal M1Is a lanthanide, scandium, or yttrium. The lanthanide series of elements includes the 15 elements with atomic numbers 57-71, any one of which is acceptable. Metal M1Preferred examples of (b) include samarium Sm, neodymium Nd, praseodymium Pr, gadolinium Gd, cerium Ce, holmium Ho, scandium Sc, and yttrium Y.
In the formula (VII), CpRIs unsubstituted/substituted indenyl. Cp having indenyl ring as basic skeletonRCan be represented as C9H7-XRXOr C9H11-XRXWherein X is an integer in the range of 0 to 7 or 0 to 11; r preferably each independently represents a hydrocarbyl group or a metalloid group; the number of carbon atoms of the hydrocarbon group is preferably in the range of 1 to 20, more preferably in the range of 1 to 10, and still more preferably in the range of 1 to 8. Specifically, preferred examples of the hydrocarbon group include methyl, ethyl, phenyl, benzyl and the like. Examples of metalloids of the metalloid group includeGermylge, stannyl Sn, and silyl Si. The metalloid group preferably includes a hydrocarbon group defined in the same manner as the above-mentioned hydrocarbon group. Specific examples of the metalloid group include trimethylsilyl and the like.
Specific examples of the substituted indenyl group include 2-phenylindenyl and 2-methylindenyl, etc. Two Cp in the general formula (VII)RMay be of the same kind or of different kinds.
In the formula (VII), RAAnd RBEach independently represents C1-20A monovalent hydrocarbon group, and M1And Al and RAAnd RBMu coordinate. In this respect, C1-20Examples of monovalent hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl, and the like. Expression "M1And Al and RAAnd RBMu coordinate "means M1And Al and RAAnd RBCoordinated in a cross-linking manner.
In the formula (VII), RCAnd RDEach independently represents C1-20A monovalent hydrocarbon group or a hydrogen atom. In this respect, C1-20Examples of monovalent hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl, and the like.
The metallocene-based composite catalyst can be prepared by reacting a metallocene complex represented by the following formula (VIII) with AlRKRLRMThe organoaluminum compound represented by the formula (I) is obtained by reacting in a solvent.
(in the formula (VIII), M2Represents a lanthanide, scandium, or yttrium; cpREach independently represents an unsubstituted/substituted indenyl group; rE～RJEach independently represents C1-3An alkyl group or a hydrogen atom; l represents a neutral pathA lewis base; and w represents an integer in the range of 0 to 3).
The reaction temperature may be set around room temperature, which allows for manufacturing under mild conditions. The reaction time may be set as desired, and is generally in the range of several hours to several days. The kind of the reaction solvent is not limited, but a solvent capable of dissolving the raw materials and the reaction product is preferable. For example, toluene or hexane may be used. The structure of the metallocene-based composite catalyst is preferably obtained by1H-NMR or X-ray structural analysis.
In the metallocene complex represented by the general formula (VIII), CpREach independently represents an unsubstituted/substituted indenyl group and is substituted with Cp in the general formula (VII)RDefined in the same manner; metal M2Is a lanthanide, scandium, or yttrium, and is reacted with a metal M in formula (VII)1Defined in the same manner.
The metallocene complex represented by the formula (VIII) includes a silylamino ligand [ -N (SiR)3)2]. The R group included in the silylamine ligand (i.e., R in the general formula (VIII))E～RJ) Each independently represents C1-3Alkyl groups or hydrogen atoms. Preferably, R isE～RJAt least one of them is a hydrogen atom. When R isE～RJWhen at least one of them is a hydrogen atom, the catalyst can be easily synthesized. Methyl is preferred as alkyl.
The metallocene complex represented by the formula (VIII) further includes 0 to 3, preferably 0 to 1, neutral Lewis bases L. Examples of the neutral Lewis base L include tetrahydrofuran, diethyl ether, dimethylaniline, trimethylphosphine, lithium chloride, neutral olefins, and neutral diolefins and the like. When the complex includes a plurality of neutral lewis bases L, the neutral lewis bases L may be the same kind or different kinds.
The metallocene complex represented by the general formula (VIII) may exist as any one of a monomer, a dimer or other kinds of multimers.
The organoaluminum compound used for the production of the metallocene-based composite catalyst is represented by AlRKRLRMIt is shown that,wherein R isKAnd RLEach independently represents C1-20A monovalent hydrocarbon group or a hydrogen atom; rMIs represented by C1-20A monovalent hydrocarbon group; and R isMCan be with RKAnd RLThe same species or different species. C1-20Examples of monovalent hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl, and the like.
Specific examples of the organoaluminum compound include: trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-tert-butylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum; diethylaluminum hydride, di-n-propylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride, dihexylaluminum hydride, diisohexylaluminum hydride, dioctylaluminum hydride, diisooctylaluminum hydride; ethyl aluminum dihydride, n-propyl aluminum dihydride, isobutyl aluminum dihydride, and the like. Among these examples, triethylaluminum, triisobutylaluminum, diethylaluminum hydride and diisobutylaluminum hydride are preferable as the organoaluminum compound. A single species or a combination of two or more species in these examples may be used as the organoaluminum compound. The amount of the organoaluminum compound used for the production of the metallocene-based composite catalyst is preferably 1 to 50 times, more preferably about 10 times, the amount of the metallocene complex when compared in mol.
Component (A-2)
The component (A-2) is a rare earth element compound or a reaction product resulting from the reaction of a rare earth element compound with a Lewis base, wherein the rare earth element compound and the reaction product thereof respectively have no bond between the relevant rare earth metal and a carbon atom. The rare earth element compound having no bond between the relevant rare earth metal and the carbon atom or the reaction product resulting from the reaction of the rare earth element compound and the lewis base is stable as a compound and easy to handle. In the present invention, the term "rare earth element compound" refers to a compound containing a rare earth element (M) (i.e., one of lanthanoids consisting of elements having atomic numbers of 57 to 71 in the periodic table; or scandium or yttrium).
Specific examples of lanthanides include lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. A single species or a combination of two or more species in the examples may be used as the component (A-2).
The rare earth element compound preferably contains a salt or a complex of a divalent/trivalent rare earth metal, and more preferably a rare earth element compound having at least one ligand selected from a hydrogen atom, a halogen atom, and an organic compound residue. Further, the rare earth element compound or the reaction product resulting from the reaction of the rare earth element compound and the lewis base is preferably represented by the following general formula (IX) or general formula (X):
M11X11 2·L11w…(IX)
M11X11 3·L11w…(X)
(in these formulae, M11Denotes the lanthanide, scandium, or yttrium, X11Each independently represents a hydrogen atom, a halogen atom, an alkoxy group, a hydrocarbylthio group, an amino group, a silyl group, an aldehyde residue, a ketone residue, a carboxylic acid residue, a thiocarboxylic acid residue, or a phosphorus compound residue, L11Represents a Lewis base, and w represents an integer in the range of 0 to 3. )
Examples of the group (ligand) bonded to the rare earth element of the rare earth element compound include a hydrogen atom, a halogen atom, an alkoxy group (a group which is obtained by removing hydrogen from a hydroxyl group of an alcohol and which is capable of forming a metal alkoxide), a hydrocarbylthio group (a group which is obtained by removing hydrogen from a thiol group of a thiol compound and is capable of forming a metal thiolate), an amino group (a group which is obtained by removing one hydrogen atom bonded to a nitrogen atom of ammonia, a primary amine or a secondary amine and is capable of forming a metal amide), a silyl group, an aldehyde residue, a ketone residue, a carboxylic acid residue, a thiocarboxylic acid residue, and a phosphorus compound residue.
Specific examples of the group (ligand) to be bonded to the rare earth element of the rare earth element compound include: a hydrogen atom; aliphatic alkoxy groups such as methoxy, ethoxy, propoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy and the like; phenoxy group, 2, 6-di-tert-butylphenoxy group, 2, 6-diisopropylphenoxy group, 2, 6-dineopentylphenoxy group, 2-tert-butyl-6-isopropylphenoxy group, 2-tert-butyl-6-neopentylphenoxy group, 2-isopropyl-6-neopentylphenoxy group; aliphatic hydrocarbylthio groups such as thiomethoxy, thioethoxy, thiopropoxy, thio-n-butoxy, thio-isobutoxy, thio-sec-butoxy, and thio-tert-butoxy, and the like; arylhydrocarbylthio groups such as thiophenoxy, 2, 6-di-tert-butylthiophenoxy, 2, 6-diisopropylthiophenoxy, 2, 6-dineopentylthiophenoxy, 2-tert-butyl-6-isopropylthiophenoxy, 2-tert-butyl-6-thioneopentylphenoxy, 2-isopropyl-6-thioneopentylphenoxy, and 2,4, 6-triisopropylthiophenoxy, etc.; aliphatic amino groups such as dimethylamino group, diethylamino group, diisopropylamino group, and the like; arylamino groups such as phenylamino, 2, 6-di-tert-butylphenyl amino, 2, 6-diisopropylphenylamino, 2, 6-dineopentylphenylamino, 2-tert-butyl-6-isopropylphenylamino, 2-tert-butyl-6-neopentylphenylamino, 2-isopropyl-6-neopentylphenylamino, 2,4, 6-tert-butylphenyl amino, and the like; a ditrialkylsilylamino group such as a bistrimethylsilylamino group; silyl groups such as trimethylsilyl, tris (trimethylsilyl) silyl, bis (trimethylsilyl) methylsilyl, trimethylsilyl (dimethyl) silyl, triisopropylsilyl (bistrimethylsilyl) silyl, and the like; halogen atoms such as fluorine atom, chlorine atom, bromine atom, iodine atom; and the like.
Specific examples of the ligand further include: aldehyde residues such as salicylaldehyde, 2-hydroxy-1-naphthaldehyde, and 2-hydroxy-3-naphthaldehyde; residues of hydroxybenzophenones such as 2 ' -hydroxyacetophenone, 2 ' -hydroxybenzophenone, and 2 ' -hydroxypropiophenone; a residue of a diketone such as acetylacetone, benzoylacetone, propionitrile acetone, isobutyl acetone, valeryl acetone, and ethyl acetylacetone; such as isovaleric, capric, caprylic, lauric, myristic, palmitic, stearic, isostearic, oleic, linoleic, cyclopentanecarboxylic, naphthenic, ethylhexanoic, pivalic, versatic (by Shell C)Products manufactured by Chemicals, which is C10Synthetic acids formed from mixtures of isomers of monocarboxylic acids), residues of carboxylic acids such as phenylacetic acid, benzoic acid, 2-naphthoic acid, maleic acid, and succinic acid; residues of thiocarboxylic acids such as hexanethioic acid, 2-dimethylbutanethioic acid, decanethioic acid, and thiobenzoic acid; phosphoric ester residues such as dibutyl phosphate, dipentyl phosphate, dihexyl phosphate, diheptyl phosphate, dioctyl phosphate, bis (2-ethylhexyl) phosphate, bis (1-methylheptyl) phosphate, dilauryl phosphate, dioleyl phosphate, diphenyl phosphate, bis (p-nonylphenyl) phosphate, bis (polyethylene glycol-p-nonylphenyl) phosphate, butyl (2-ethylhexyl) phosphate, 1-methylheptyl (2-ethylhexyl) phosphate, and 2-ethylhexyl (p-nonylphenyl) phosphate; residues of phosphonic acid esters such as monobutyl (2-ethylhexyl) phosphonate, mono-2-ethylhexyl phenylphosphonate, mono-p-nonylphenyl (2-ethylhexyl) phosphonate, mono-2-ethylhexyl phosphonate, mono-1-methylheptyl phosphonate, and mono-p-nonylphenyl phosphonate; such as the residue of phosphinic acids such as dibutylphosphinic acid, bis (2-ethylhexyl) phosphinic acid, bis (1-methylheptyl) phosphinic acid, dilaurylphosphinic acid, dioleylphosphinic acid, diphenylphosphinic acid, bis (p-nonylphenyl) phosphinic acid, butyl (2-ethylhexyl) phosphinic acid, (2-ethylhexyl) (1-methylheptyl) phosphinic acid, (2-ethylhexyl) (p-nonylphenyl) phosphinic acid, butylphosphinic acid, 2-ethylhexyl phosphinic acid, 1-methylheptylphosphinic acid, oleylphosphinic acid, laurylphosphinic acid, phenylphosphinic acid, and p-nonylphenylphosphinic acid. A single species or a combination of two or more species from the above examples may be used as the ligand.
Examples of the lewis base to be reacted with the rare earth element compound include tetrahydrofuran, diethyl ether, dimethylaniline, trimethylphosphine, lithium chloride, neutral olefins, neutral diolefins and the like. In this regard, in the case where the rare earth element compound is reacted with a plurality of lewis bases (i.e., in the case where w ═ 2 or 3 in formula (IX) and formula (X)), these lewis bases L11May be of the same kind or of different kinds.
The rare earth element compound is preferably a compound represented by the following general formula (XI).
M-(AQ1)(AQ2)(AQ3)…(XI)
(in the general formula (XI), M represents an element selected from scandium, yttrium and lanthanoids; AQ1、AQ2And AQ3Represent functional groups that may be the same kind or different kinds; "A" represents an element selected from nitrogen, oxygen and sulfur; and the compound substantially comprises at least one M-a bond).
Specific examples of lanthanides include lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. The above compound is a component capable of improving catalytic activity in a reaction system, shortening reaction time, and increasing reaction temperature.
From the viewpoint of improving the catalytic activity and reaction controllability, gadolinium is preferable as "M" in the general formula (XI).
When "A" in the formula (XI) represents nitrogen, the compound is represented by AQ1、AQ2And AQ3(i.e., NQ)1、NQ2And NQ3) Examples of the functional group include amino group and the like. In this case, the rare earth element compound has three M-N bonds.
Examples of the amino group include: aliphatic amino groups such as dimethylamino group, diethylamino group, diisopropylamino group; arylamino groups such as phenylamino, 2, 6-di-tert-butylphenyl amino, 2, 6-diisopropylphenylamino, 2, 6-dineopentylphenylamino, 2-tert-butyl-6-isopropylphenylamino, 2-tert-butyl-6-neopentylphenylamino, 2-isopropyl-6-neopentylphenylamino, and 2,4, 6-tri-tert-butylphenyl amino, etc.; and ditrialkylsilylamino groups such as bistrimethylsilylamino groups. Among these examples, bistrimethylsilylamino is preferred as the amino group from the viewpoint of solubility to aliphatic and aromatic hydrocarbons. A single species or a combination of two or more species in these examples may be used as the amino group.
According to the above structural feature, the component (A-2) may be a compound having three M-N bonds chemically equivalent to each other, whereby the component (A-2) has a stable structure and is easy to handle.
Further, according to the above structural features, the catalytic activity in the reaction system can be further improved. Thereby further shortening the reaction time and further increasing the reaction temperature.
When "A" in the formula (XI) is oxygen, the formula (XI) (i.e., M- (OQ)1)(OQ2)(OQ3) The kind of the rare earth element-containing compound is not particularly limited. In this case, examples of the rare earth element-containing compound include:
a rare earth alcoholate represented by the following general formula (XII); and
(RO)3M…(XII)
a rare earth carboxylate represented by the following general formula (XIII).
(R-CO2)3M…(XIII)
In the general formula (XII) and the general formula (XIII), "R" represents C1-10Alkyl groups, which may be the same species or different species.
When "A" in formula (XI) is sulfur, the compound represented by formula (XI) (i.e., M- (SQ)1)(SQ2)(SQ3) The kind of the rare earth element-containing compound is not particularly limited. In this case, examples of the rare earth element-containing compound include:
a rare earth alkyl mercaptide represented by the following general formula (XIV); and
(RS)3M…(XIV)
a compound represented by the following general formula (XV).
(R-CS2)3M…(XV)
In the general formula (XIV) and the general formula (XV), "R" represents C respectively1-10Alkyl groups, which may be the same species or different species.
The organometallic compound (B) used in the catalyst composition is represented by the following general formula (I):
YR1 aR2 bR3 c…(I)
(in the general formula (I), Y represents a metal selected from the group consisting of
in the general formula (I), from R1、R2And R3Is represented by C1-10Specific examples of the hydrocarbon group include: straight/branched aliphatic hydrocarbon groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, neopentyl, hexyl, octyl and the like; aromatic hydrocarbon groups such as phenyl, tolyl, and naphthyl; aralkyl groups such as benzyl; and the like. Among these examples, methyl, ethyl, isobutyl, and the like are preferable.
The organometallic component (B) is preferably an organoaluminum compound represented by the general formula (XVI):
AlR1R2R3…(XVI)
(in the general formula (XVI), R1And R2Each represents C1-10A hydrocarbon group or a hydrogen atom, and R3Is represented by C1-10A hydrocarbon group, wherein R1、R2And R3May be of the same kind or of different kinds. ) The organoaluminum compound corresponds to a compound represented by general formula (I) wherein Y is Al and a ═ b ═ c ═ 1.
Examples of the organoaluminum compound represented by the general formula (XVI) include trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-t-butylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum; diethylaluminum hydride, di-n-propylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride, dihexylaluminum hydride, diisohexylaluminum hydride, dioctylaluminum hydride, diisooctylaluminum hydride, ethylaluminum dihydride, n-propylaluminum dihydride, and isobutylaluminum dihydride, etc. Among these examples, triethylaluminum, triisobutylaluminum, diethylaluminum hydride, and diisobutylaluminum hydride are preferable as the organoaluminum compound.
A single species or a combination of two or more species in the above examples may be used as the organometallic compound (B).
The content of the organometallic compound (B) is preferably 1 to 50 times, more preferably about 10 times, the content of the rare earth element-containing compound (A) in mol.
The ionic compound (C) which can be used in the catalyst composition is composed of a non-coordinating anion and a cation. Examples of the ionic compound (C) include ionic compounds and the like which can react with the rare earth element-containing component (a) and generate a cationic transition metal compound.
Examples of the non-coordinating anion include tetravalent boron anions such as tetraphenyl borate, tetrakis (mono-fluorophenyl) borate, tetrakis (difluorophenyl) borate, tetrakis (trifluorophenyl) borate, tetrakis (tetrafluorophenyl) borate, tetrakis (pentafluorophenyl) borate, tetrakis (tetrafluoromethylphenyl) borate, tetrakis (tolyl) borate, tetraxylyl borate, triphenyl (pentafluorophenyl) borate, [ tris (pentafluorophenyl) phenyl ] borate, tridecyl-7, 8-dicarbonylundecanoborate, and the like. Of these examples, tetrakis (pentafluorophenyl) borate is preferred as the tetravalent boron anion.
Examples of cations include carbonium cations, oxonium cations, amine cations, phosphonium cations, cycloheptatriene cations, and transition metal-containing ferrocenium cations, among others. Specific examples of the carbonium cation include trisubstituted carbonium cations such as triphenylcarbonium cation (which is also referred to as "trityl cation"), and tris (substituted phenyl) carbonium cation, and the like. Specific examples of the tri (substituted phenyl) carbonium cation include a tri (methylphenyl) carbonium cation, a tri (dimethylphenyl) carbonium cation, and the like. Examples of amine cations include ammonium cations and the like. Specific examples of ammonium cations include: trialkylammonium cations such as trimethylammonium cation, triethylammonium cation, tripropylammonium cation, tributylammonium cation (e.g., tri (n-butyl) ammonium cation); n, N-dialkylanilinium cations such as N, N-dimethylanilinium cation, N-diethylanilinium cation, N-2,4, 6-pentamethylanilinium cation; dialkylammonium cations such as diisopropylammonium cation, dicyclohexylammonium cation; and the like. Specific examples of the phosphonium cation include triarylphosphonium cations such as triphenylphosphonium cation, tris (methylphenyl) phosphonium cation, tris (dimethylphenyl) phosphonium cation, and the like. Among these examples of the cation, an N, N-dialkylanilinium cation or a carbonium cation is preferable, and an N, N-dialkylanilinium cation is particularly preferable.
Therefore, a compound as a combination of non-coordinating anions and cations respectively selected from the above examples is preferably used as the ionic compound (C). Specifically, N-dimethylaniline tetrakis (pentafluorophenyl) borate, triphenylcarbenium tetrakis (pentafluorophenyl) borate (also referred to as "trityl tetrakis (pentafluorophenyl) borate", and the like are preferable as the ionic compound (C).
A single species or a combination of two or more species in the above examples may be used as the ionic compound (C). The content of the ionic compound (C) in the catalyst composition is preferably 0.1 to 10 times, more preferably about 1 time, the content of the rare earth element-containing compound (a) in mol.
Examples of the halogen compound (D) which can be used in the catalyst composition include: the halogen compound (D) is, for example, a compound which can react with the rare earth element-containing compound (A) to form a cationic transition metal compound, a halogenated transition metal compound, or a compound having an insufficient charge at the center of the transition metal.
Examples of the component (D-1) include halogen compounds containing an element of group 3,4, 5,6, 8, 13, 14 or 15 of the periodic Table. Preferred examples of the component (D-1) include aluminum halides or organometallic halides. Chlorine or bromine is preferred as halogen element.
Specific examples of the halogen-containing compound as the lewis acid include methyl aluminum dibromide, methyl aluminum dichloride, ethyl aluminum dibromide, ethyl aluminum dichloride, butyl aluminum dibromide, butyl aluminum dichloride, dimethyl aluminum bromide, dimethyl aluminum chloride, diethyl aluminum bromide, diethyl aluminum chloride, dibutyl aluminum bromide, dibutyl aluminum chloride, methyl aluminum sesquibromide, methyl aluminum sesquichloride, ethyl aluminum sesquibromide, ethyl aluminum sesquichloride, dibutyl tin dichloride, aluminum tribromide, tris (pentafluorophenyl) aluminum, tris (pentafluorophenyl) borate, antimony trichloride, antimony pentachloride, phosphorus trichloride, phosphorus pentachloride, tin tetrachloride, titanium tetrachloride, tungsten hexachloride, and the like. Among these examples, diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, diethylaluminum bromide, ethylaluminum sesquibromide, and ethylaluminum dibromide are particularly preferable as the component (D-1).
A single species or a combination of two or more species in these examples may be used as the component (D-1).
Examples of the metal halide constituting the above-mentioned component (D-2) include beryllium chloride, beryllium bromide, beryllium iodide, magnesium chloride, magnesium bromide, magnesium iodide, calcium chloride, calcium bromide, calcium iodide, barium chloride, barium bromide, barium iodide, zinc chloride, zinc bromide, zinc iodide, cadmium chloride, cadmium bromide, cadmium iodide, mercury chloride, mercury bromide, mercury iodide, manganese chloride, manganese bromide, manganese iodide, rhenium chloride, rhenium bromide, rhenium iodide, copper chloride, copper iodide, silver chloride, silver bromide, silver iodide, gold chloride, gold iodide, gold bromide and the like. Among these examples, magnesium chloride, calcium chloride, barium chloride, manganese chloride, zinc chloride and copper chloride are preferable as the metal halide. Magnesium chloride, manganese chloride, zinc chloride and copper chloride are particularly preferred.
Further, preferable examples of the Lewis base constituting the component (D-2) include phosphorus compounds, carbonyl compounds, nitrogen compounds, ether compounds, alcohols and the like. Specifically, acceptable examples of the lewis base include tributyl phosphate, tri-2-ethylhexyl phosphate, triphenyl phosphate, tricresyl phosphate, triethylphosphine, tributylphosphine, triphenylphosphine, diethylphosphinoethane, diphenylphosphinoethane, acetylacetone, benzoylacetone, propionylacetone, valerylacetone, ethylacetoacetone, methyl acetoacetate, ethyl acetoacetate, phenyl acetoacetate, dimethyl malonate, diethyl malonate, diphenyl malonate, acetic acid, octanoic acid, 2-ethylhexanoic acid, oleic acid, stearic acid, benzoic acid, naphthenic acid, versatic acid, triethylamine, N-dimethylacetamide, tetrahydrofuran, diphenyl ether, 2-ethylhexyl alcohol, oleyl alcohol, stearyl alcohol, phenol, benzyl alcohol, 1-decanol, lauryl alcohol and the like. Among these examples, tri-2-ethylhexyl phosphate, tricresyl phosphate, acetylacetone, 2-ethylhexanoic acid, versatic acid, 2-ethylhexyl alcohol, 1-decanol, and lauryl alcohol are preferable as Lewis bases.
0.01 to 30mol (preferably 0.5 to 10mol) of the Lewis base is reacted with 1mol of the metal halide. By using the reaction product thus obtained from the reaction of the metal halide with the Lewis base, the metal remaining in the copolymer can be reduced.
A single species or a combination of two or more species in the above examples may be used as the component (D-2).
Examples of the above-mentioned component (D-3) include benzyl chloride and the like.
A single species or a combination of two or more species in examples thereof may be used as the halogen compound (D).
The content of the halogen compound (D) in the catalyst composition is preferably 0 to 5 times, more preferably 1 to 5 times, the content of the rare earth element-containing compound (a) in mol.
In the first production method of the copolymer of the present invention, the compound (E) used in the catalyst composition is selected from the group consisting of a non-conjugated olefin compound and a conjugated diene compound. Therefore, in the first production method of the copolymer of the present invention, it is possible to reduce the endothermic energy at the endothermic peak in the range of 100 to 150 ℃ determined by DSC measurement of the resulting copolymer, and thus reduce the crystallinity derived from the non-conjugated olefin unit in the range of 100 to 150 ℃ measured by DSC, by using the compound (E) in the catalyst composition.
In the second production method of the copolymer of the present invention, the compound (E') used in the catalyst composition is selected from the group consisting of a non-conjugated olefin compound and a conjugated diene compound, which are different in kind from the non-conjugated olefin compound and the conjugated diene compound as monomers copolymerized in the copolymerization step. Therefore, in the second production method of the copolymer of the present invention, it is possible to reduce the endothermic energy at the endothermic peak in the range of 100 to 150 ℃ determined by DSC measurement of the resulting copolymer, and thus reduce the crystallinity derived from the non-conjugated olefin unit in the range of 100 to 150 ℃ measured by DSC, by using the compound (E') in the catalyst composition.
The non-conjugated olefin compound used in the catalyst composition means an aliphatic unsaturated hydrocarbon compound having one or more carbon-carbon double bonds. Examples of the non-conjugated olefin compound include non-cyclic non-conjugated olefin compounds and cyclic non-conjugated olefin compounds.
Examples of the acyclic unconjugated olefin compound include α -olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene, and the like.
Examples of the cyclic nonconjugated olefin compound include: cyclic olefins such as cyclopentene, cyclohexene, cycloheptene, cyclooctene, methylcyclopentene, methylcyclohexene, methylcycloheptene, methylcyclooctene, ethylcyclopentene, ethylcyclohexene, ethylcycloheptene, ethylcyclooctene, dimethylcyclopentene, dimethylcyclohexene, dimethylcycloheptene, dimethylcyclooctene; and compounds having a crosslinked structure such as norbornene (which is sometimes referred to as "2-norbornene"), 5-methyl-2-norbornene, 5-ethyl-2-norbornene, 5-n-butyl-2-norbornene, 5-n-hexyl-2-norbornene, 5-n-decyl-2-norbornene, 5-cyclohexyl-2-norbornene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, 5-phenyl-2-norbornene, 5-benzyl-2-norbornene, dicyclopentadiene, methyldicyclopentadiene, ethyldicyclopentadiene and the like.
Of these examples, norbornene and dicyclopentadiene are preferred as the non-conjugated olefin compounds used in the catalyst composition. It is difficult to introduce norbornene and dicyclopentadiene into the copolymer, and thus it is possible to further reduce the endothermic energy at the endothermic peak in the range of 100 to 150 ℃ as determined by DSC measurement of the resulting copolymer by using norbornene and dicyclopentadiene, and thus further reduce the crystallinity derived from the non-conjugated olefin unit in the range of 100 to 150 ℃ as measured by DSC.
Examples of the conjugated diene compound used in the catalyst composition include 1, 3-butadiene, isoprene, 1, 3-pentadiene, and 2, 3-dimethylbutadiene, and the like. Among these examples, 1, 3-butadiene and isoprene are preferable, and 1, 3-butadiene is particularly preferable. When 1, 3-butadiene is used as the compound (E), 1, 3-butadiene is sufficiently incorporated into the catalyst composition due to the aging process, whereby 1, 3-butadiene is not incorporated into the copolymer in the copolymerization process, so that it is possible to further reduce the endothermic energy at the endothermic peak in the range of 100 to 150 ℃ as determined by DSC measurement of the resulting copolymer, and thus to further reduce the crystallinity derived from the non-conjugated olefin unit in the range of 100 to 150 ℃ as measured by DSC.
The cyclic nonconjugated olefin compound is preferably used as the compound (E) or the compound (E'). The cyclic nonconjugated olefin compound is only poorly incorporated into the copolymer, and in particular, thereby it is possible to further reduce the endothermic energy at the endothermic peak in the range of 100 ℃ to 150 ℃ determined by DSC measurement of the resulting copolymer, and thus further reduce the crystallinity derived from the nonconjugated olefin unit in the range of 100 ℃ to 150 ℃ measured by DSC, by using the cyclic nonconjugated olefin compound.
The non-conjugated olefin compound having three or more carbon atoms is also preferable as the compound (E) or the compound (E'). It is difficult to introduce a non-conjugated olefin compound having three or more carbon atoms into the copolymer, and thus it is possible to further reduce the endothermic energy at the endothermic peak in the range of 100 ℃ to 150 ℃ as determined by DSC measurement of the resulting copolymer, and thus further reduce the crystallinity derived from non-conjugated olefin units in the range of 100 ℃ to 150 ℃ as measured by DSC, by using a cyclic non-conjugated olefin compound.
When the compound (E) or the compound (E ') is a non-conjugated olefin compound, the content of the compound (E) or the compound (E') in the catalyst composition is preferably at least 10 times, more preferably 50 to 10,000 times, the content of the rare earth element-containing compound (a) when compared in mol. When the compound (E) or the compound (E ') is a conjugated diene compound, the content of the compound (E) or the compound (E') in the catalyst composition is preferably at least 1 time, more preferably 3 to 1,000 times, the content of the rare earth element-containing compound (a) when compared in mol. When the content of the compound (E) or the compound (E ') is set within the above range, the compound (E) or the compound (E') can exert its excellent effect in a satisfactory manner, whereby the endothermic energy at the endothermic peak in the range of 100 to 150 ℃ as determined by DSC measurement of the resulting copolymer can be further reduced, and thus the crystallinity derived from the nonconjugated olefin unit in the range of 100 to 150 ℃ as measured by DSC can be further reduced.
The catalyst composition may further comprise an aluminoxane (F). The aluminoxane (F) is a compound obtained by contacting an organoaluminum compound with a condensing agent. The catalytic activity in the polymerization reaction system can be further increased by using the aluminoxane (F) i) so that the objective copolymer can be easily obtained, ii) to further shorten the reaction time and to increase the reaction temperature.
Examples of the above-mentioned organoaluminum compounds include trialkylaluminums such as trimethylaluminum, triethylaluminum, triisobutylaluminum and mixtures thereof. Of these examples, trimethylaluminum and a mixture of trimethylaluminum and tributylaluminum are preferred as the organoaluminum compound.
Examples of the condensing agent include water and the like.
Examples of the aluminoxane (F) include aluminoxanes represented by the following general formula (XVII):
-(Al(R7)O)n-…(XVII)
(in the general formula (XVII), R7Is represented by C1-10A hydrocarbyl group; a part of the hydrocarbon group may be substituted with a halogen atom and/or an alkoxy group; each R7The same species or different species may be present in the repeating unit; and n is preferably ≧ 5).
The molecular structure of the aluminoxane may be linear or cyclic.
Preferably, "n" in the general formula (XVII) is ≧ 10.
Further, as R in the general formula (XVII)7Examples of the hydrocarbon group of (1) include methyl, ethyl, propyl, isobutyl and the like. Among these examples, methyl is particularly preferred. A single species or a combination of two or more species in these examples may be used as the hydrocarbon group. In this respect, it is preferred to use methyl and isobutyl groups in combination as R in the general formula (XVII)7Or a hydrocarbyl group.
Preferably, the aluminoxane has high solubility to aliphatic hydrocarbons and low solubility to aromatic hydrocarbons. Preferred examples of the aluminoxane include commercially available aluminoxanes sold as hexane solutions.
Examples of the aliphatic hydrocarbon include hexane, cyclohexane and the like.
Acceptable examples of the aluminoxane (F) include, in particular, modified aluminoxanes represented by the general formula (XVIII) (which are hereinafter sometimes referred to as "TMAO").
-(Al(CH3)x(i-C4H9)yO)m-…(XVIII)
(in the general formula (XVIII), x + y is 1; "m" is 5. gtoreq.)
Examples of TMAO include those manufactured by Tosoh Finechem Corporation under the trade name "TMAO-341".
Specifically, the aluminoxane (F) may be a modified aluminoxane represented by the general formula (XIX) (this specific modified aluminoxane is hereinafter sometimes referred to as "MMAO").
-(Al(CH3)0.7(i-C4H9)0.3O)k-…(XIX)
(in the general formula (XIX), "k" is 5 or more.)
Examples of MMAO include those manufactured by Tosoh Finechem Corporation under the trade name "MMAO-3A".
Alternatively, acceptable examples of the aluminoxane (F) specifically include modified aluminoxanes represented by the general formula (XX) (which are hereinafter sometimes referred to as "PMAO").
-[(CH3)AlO]i-…(XX)
(in the general formula (XX), "i" is 5 or more.)
Examples of PMAO include those manufactured by Tosoh Finechem Corporation under the trade name "PMAO-211".
Among the MMAO, TMAO and PMAO, the aluminoxane (F) is preferably MMAO or TMAO from the viewpoint of enhancing the catalytic activity-improving effect, and particularly TMAO is more preferably from the viewpoint of further enhancing the catalytic activity-improving effect.
The first production method of the copolymer of the present invention includes a step of aging a catalyst composition (this step is hereinafter sometimes referred to as "aging step") containing: a rare earth element-containing compound (A), at least one compound selected from the group consisting of an organic metal compound (B), an ionic compound (C) and a halogen compound (D), and at least one compound (E) selected from the group consisting of a non-conjugated olefin compound and a conjugated diene compound. The details of the aging process are not particularly limited, and the catalyst composition may be simply left to stand or stirred, the catalyst composition comprising: a rare earth element-containing compound (A), at least one compound selected from the group consisting of an organometallic compound (B), an ionic compound (C) and a halogen compound (D), and a compound (E). The aging process may include heating the catalyst composition. The temperature in the aging step is preferably in the range of 0 to 100 ℃ and more preferably in the range of 10 to 80 ℃. The time period of the aging process is not particularly limited, and may be, for example, in the range of 1 second to 1,000 hours, preferably in the range of 10 seconds to 500 hours, and more preferably in the range of 5 minutes to 300 hours.
The first/second production method of the copolymer of the present invention comprises: a step of copolymerizing a non-conjugated olefin compound and a conjugated diene compound as monomers in the presence of the catalyst composition (this step may be hereinafter referred to as "copolymerization step"). In the case where the copolymer contains an aromatic vinyl unit, in the copolymerization step, a non-conjugated olefin compound, a conjugated diene compound and an aromatic vinyl compound as monomers are copolymerized in the presence of the above-mentioned catalyst composition. The first/second production method of the copolymer of the present invention may further comprise a coupling step, a washing step and other steps as necessary, in addition to the copolymerization step.
Any polymerization method such as solution polymerization, suspension polymerization, liquid-phase bulk polymerization, emulsion polymerization, gas-phase polymerization, or solid-phase polymerization may be used for the copolymerization process. In the case of using a solvent in the relevant copolymerization reaction, any solvent is acceptable as long as the solvent is inert in the copolymerization reaction. Examples of the solvent include toluene and hexane (e.g., cyclohexane, n-hexane), and the like.
In the first/second production method of the copolymer of the present invention, the copolymerization step may be performed in one step, or may be performed in a plurality of (i.e., two or more) steps. The copolymerization step carried out in one step means a step of carrying out copolymerization by simultaneously reacting all monomers to be polymerized. The copolymerization process carried out in multiple steps means a process of carrying out copolymerization by first reacting part/whole of one/two or more monomers to form a polymer or copolymer (first polymerization step), and then adding the remaining part of the monomer of the first polymerization step and the remaining kind of monomers not used in the first polymerization step to thereby form a polymer or copolymer, thereby completing copolymerization (second polymerization step to final polymerization step).
The bond content (cis-1, 4 bond content, trans-1, 4 bond content, 3,4 vinyl bond content, and 1,2 vinyl bond content) in the entire conjugated diene units of the copolymer thus produced, as well as the content of units derived from each monomer (i.e., the copolymerization ratio of each monomer) can be controlled by controllably changing the order and amount of charging of each monomer to the reaction vessel and other reaction conditions in the presence of the above-described catalyst composition.
In the second method for producing a copolymer of the present invention, the copolymerization step preferably includes charging the compound (E') into the reaction vessel at a stage of first charging the conjugated diene compound as a monomer into the reaction vessel. By charging the compound (E ') to the reaction vessel at the stage where the conjugated diene compound as a monomer is first charged to the reaction vessel, the effect caused by the compound (E') can be maximized and the chain length of the non-conjugated olefin unit can be satisfactorily shortened. In this aspect, the charging of the non-conjugated olefin compound as a monomer into the reaction vessel may be carried out in any one of the following stages: before the conjugated diene compound as a monomer is first charged into a reaction vessel; after first charging a conjugated diene compound as a monomer into a reaction vessel; when the conjugated diene compound as a monomer is first charged into the reaction vessel (i.e., simultaneously). Further, in the case of using an aromatic vinyl compound, the charging of the aromatic vinyl compound into the reaction vessel may be carried out in any one of the following stages: before the conjugated diene compound as a monomer is first charged into a reaction vessel; after first charging a conjugated diene compound as a monomer into a reaction vessel; when the conjugated diene compound as a monomer is first charged into the reaction vessel (i.e., simultaneously).
In the first/second production method of the copolymer of the present invention, the copolymerization step is preferably performed in an inert gas atmosphere, and desirably in a nitrogen or argon atmosphere. The temperature in the polymerization step is not particularly limited, but is preferably in the range of-100 ℃ to 200 ℃ and may be, for example, around room temperature. An excessively high reaction temperature may adversely affect the selectivity of cis-1, 4 bonds of the conjugated diene units of the copolymer. The pressure during the copolymerization step is preferably in the range of 0.1MPa to 10.0MPa from the viewpoint of trapping a sufficient amount of the acyclic unconjugated olefin compound in the copolymerization reaction system. The reaction time in the copolymerization step is not particularly limited, but is preferably in the range of 1 second to 10 days, for example. The reaction time can be appropriately set according to conditions such as a desired microstructure of the obtained copolymer, the kind of each monomer, the amount and order of the monomers to be charged, the kind of the catalyst, and the reaction temperature. In the copolymerization step, the copolymerization reaction can be terminated by using a polymerization terminator such as methanol, ethanol, isopropanol, or the like.
The coupling step is a step of modifying at least a part (for example, a terminal) of a polymer chain of the copolymer obtained in the copolymerization step to perform a reaction (coupling reaction). The coupling reaction is preferably carried out when the conversion of the copolymerization reaction reaches 100%.
The kind of the coupling agent used in the coupling reaction is not particularly limited and may be appropriately selected depending on the intended use. Examples of coupling agents include: (i) tin-containing compounds such as bis (1-octadecyl maleate) dioctyltin (IV); (ii) isocyanate compounds such as 4, 4' -diphenylmethane diisocyanate; (iii) alkoxysilane compounds such as glycidylpropyltrimethoxysilane; and the like. A single species or a combination of two or more species in these examples may be used as the coupling agent. Among these examples, bis (1-octadecyl maleate) dioctyltin (IV) is preferable as the coupling agent from the viewpoint of high reaction efficiency and relatively little gel formation.
The washing step is a step of washing the copolymer obtained in the copolymerization step. The kind of the solvent used in the washing process is not particularly limited and may be appropriately selected depending on the intended use. Examples of the solvent include methanol, ethanol, isopropanol, and the like. In particular, when a catalyst derived from a lewis acid is used as the polymerization catalyst, an acid (e.g., hydrochloric acid, sulfuric acid, nitric acid) may be added to such a solvent as described above in the washing process for use. The amount of the acid added is preferably 15 mol% or less with respect to the solvent. The addition of the acid in an amount exceeding 15 mol% relative to the solvent may cause the acid to remain in the copolymer, possibly adversely affecting the kneading process and the vulcanization reaction. The residual amount of the catalyst in the copolymer can be reduced to an appropriate level by the washing step.
< rubber composition >
The rubber composition of the present invention is characterized by comprising the above copolymer. The rubber composition of the present invention having high wear resistance and high crack growth resistance can reduce the rolling resistance of a tire when applied to the tire.
The rubber composition of the present invention comprises the above-mentioned copolymer as a rubber component, and optionally may further comprise other rubber components, fillers, crosslinking agents and other components.
The content of the copolymer in the rubber component of the rubber composition of the present invention is preferably within a range of 10 to 100% by mass, more preferably within a range of 20 to 100% by mass, and still more preferably within a range of 30 to 100% by mass. When the content of the copolymer in the rubber component of the rubber composition is 10% by mass or more, the intended effect of the copolymer will be sufficiently exhibited, thereby further improving the wear resistance and crack growth resistance of the rubber composition and further reducing the rolling resistance of the tire when the rubber composition is applied to the tire.
The kind of the rubber component other than the copolymer of the present invention is not particularly limited and may be appropriately selected depending on the use. Examples of the other rubber component include Natural Rubber (NR), polyisoprene rubber (IR), polybutadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber, ethylene-propylene rubber (EPM), ethylene-propylene-nonconjugated diene rubber (EPDM), polysulfide rubber, silicone rubber, fluorine rubber, urethane rubber, and the like. A single species or a combination of two or more species in these examples may be used as the other rubber component.
The rubber composition can be improved in its reinforcing property by containing a filler therein. The kind of the filler is not particularly limited, and examples thereof include carbon black, silica, aluminum hydroxide, clay, alumina, talc, mica, kaolin, glass spheres, glass beads, calcium carbonate, magnesium hydroxide, magnesium oxide, titanium dioxide, potassium titanate, barium sulfate, and the like. Among these examples, carbon black is preferably used. A single species or a combination of two or more species in these examples may be used as the filler.
The content of the filler is not particularly limited and may be appropriately selected depending on the application, but is preferably 10 to 100 parts by mass, more preferably 20 to 80 parts by mass, and most preferably 30 to 60 parts by mass, based on 100 parts by mass of the rubber component. The content of the filler of 10 parts by mass or more relative to 100 parts by mass of the rubber component ensures the effect of improving the reinforcement of the rubber composition by the filler. The content of the filler is 100 parts by mass or less with respect to 100 parts by mass of the rubber component, ensuring good processability of the rubber composition.
The kind of the crosslinking agent is not particularly limited and may be appropriately selected depending on the use. Examples of the crosslinking agent include a sulfur-based crosslinking agent, an organic peroxide-based crosslinking agent, an inorganic crosslinking agent, a polyamine crosslinking agent, a resin crosslinking agent, a sulfur compound-based crosslinking agent, an oxime-nitrosamine-based crosslinking agent, and the like. Among these examples, a sulfur-based crosslinking agent (sulfur-based vulcanizing agent) is preferably applied to the rubber composition for a tire.
The content of the crosslinking agent is not particularly limited and may be appropriately selected depending on the use, but is preferably in the range of 0.1 to 20 parts by mass with respect to 100 parts by mass of the rubber component.
The vulcanization accelerator may be used in combination with a vulcanizing agent. Examples of the vulcanization accelerator include guanidine series, aldehyde-amine series, aldehyde-ammonia series, thiazole series, sulfenamide series, thiourea series, thiuram series, dithiocarbamate series, xanthate series, and the like.
Further, other known additives such as a softening agent, a vulcanization-accelerating assistant, a coloring agent, a flame retardant, a lubricant, a foaming agent, a plasticizer, a processing aid, an antioxidant, an anti-aging agent, an anti-scorching agent, an ultraviolet ray protecting agent, an antistatic agent, and a coloring preventing agent may be optionally used in the rubber composition of the present invention depending on the use.
The rubber composition of the present invention is suitable for vibration-proof rubber, vibration-isolating rubber, belts such as conveyor belts and rubber crawler belts, and various hoses, in addition to the following tires.
< tire >
The tire of the present invention is characterized by using the above rubber composition. The tire of the present invention thus exhibits high wear resistance and high crack growth resistance, as well as low rolling resistance.
The tire site to which the rubber composition of the present invention is applied is not particularly limited, and the tire site may be appropriately selected depending on the use. Examples of tire locations include treads, subtreads, sidewalls, sidewall reinforcing rubber, and bead fillers, among others.
The tire of the present invention can be manufactured by a conventional method. For example, a desired tire such as a pneumatic tire may be manufactured by: laminating members generally used for tire manufacture such as a carcass layer made of an unvulcanized rubber composition and/or cords, a belt layer, and a tread layer in this order on a tire forming drum; removing the drum to obtain a green tyre; and the green tire is heated and vulcanized according to a conventional method.
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