阅读说明：本技术 改性共轭二烯类聚合物及其制备方法 (Modified conjugated diene polymer and preparation method thereof ) 是由 孙海星 金魯马 金镇英 徐庆昌 李相美 于 2017-04-17 设计创作，主要内容包括：本发明提供一种包含由氨基硅烷类化合物衍生的官能团的改性共轭二烯类聚合物、其制备方法和包含所述改性共轭二烯类聚合物的橡胶组合物。所述改性共轭二烯类聚合物在主链的一个末端包含由式1的氨基硅烷类化合物衍生的官能团,由此,表现出高改性率。当将所述聚合物应用于橡胶组合物中时,可以表现出与填料的优异的亲和力,结果,可以防止橡胶组合物中填料的聚集,并且可以提高填料的分散性,从而改善橡胶组合物的加工性能。(The present invention provides a modified conjugated diene-based polymer containing a functional group derived from an aminosilane-based compound, a method for producing the same, and a rubber composition containing the modified conjugated diene-based polymer. The modified conjugated diene-based polymer includes a functional group derived from the aminosilane-based compound of formula 1 at one end of the main chain, thereby exhibiting a high modification ratio. When the polymer is applied to a rubber composition, excellent affinity with a filler can be exhibited, and as a result, aggregation of the filler in the rubber composition can be prevented and dispersibility of the filler can be improved, thereby improving processability of the rubber composition.)

1. A modified conjugated diene-based polymer comprising: a functional group derived from an aminosilane-based compound of the following formula 1:

[ formula 1]

In the formula 1, the first and second groups,

A¹and A²Each independently a substituted or unsubstituted divalent hydrocarbon group of 1 to 20 carbon atoms,

R¹to R⁴Each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms,

L¹to L⁴Each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms.

2. The modified conjugated diene polymer according to claim 1, wherein in formula 1, A is¹And A²Each independently selected from the group consisting of substituted or unsubstituted alkylene of 1 to 20 carbon atoms, arylene of 6 to 20 carbon atoms, and- [ (X)_m-(Y)_n]-, wherein X and Y are each independently a substituted or unsubstituted alkylene group of 1 to 20 carbon atoms, or an arylene group of 6 to 20 carbon atoms, X and Y are not identical, and m and n are each independently an integer of 1 to 3.

3. The modified conjugated diene polymer according to claim 1, wherein R is represented by formula 1¹To R⁴Each independently selected from the group consisting of substituted or unsubstituted alkyl of 1 to 20 carbon atoms, alkenyl of 2 to 20 carbon atoms, alkynyl of 2 to 20 carbon atoms, cycloalkyl of 3 to 20 carbon atoms, aryl of 6 to 20 carbon atoms, arylalkyl of 7 to 20 carbon atoms and alkylaryl of 7 to 20 carbon atoms.

4. The modified conjugated diene polymer according to claim 1, wherein, in formula 1, L¹To L⁴Each independently selected from the group consisting of substituted or unsubstituted alkyl of 1 to 20 carbon atoms, alkenyl of 2 to 20 carbon atoms, alkynyl of 2 to 20 carbon atoms, cycloalkyl of 3 to 20 carbon atoms, aryl of 6 to 20 carbon atoms, arylalkyl of 7 to 20 carbon atoms and alkylaryl of 7 to 20 carbon atoms.

5. The modified conjugated diene-based polymer according to claim 1, wherein, in formula 1,

A¹and A²Each independently an alkylene group of 1 to 3 carbon atoms,

R¹to R⁴Each independently an alkyl group of 1 to 6 carbon atoms,

L¹to L⁴Each independently an alkyl group of 1 to 6 carbon atoms.

6. The modified conjugated diene polymer according to claim 1, wherein the aminosilane compound is one selected from the group consisting of the following formulas 1a to 1c, or a mixture of two or more thereof,

[ formula 1a ]

[ formula 1b ]

[ formula 1c ]

7. The modified conjugated diene polymer according to claim 1, wherein the modified conjugated diene polymer is a modified polymer of a conjugated diene polymer selected from a homopolymer of a conjugated diene monomer and a copolymer of a conjugated diene monomer and an aromatic vinyl monomer.

8. The modified conjugated diene-based polymer according to claim 1, wherein the modified conjugated diene-based polymer has a number average molecular weight of 50,000 to 2,000,000g/mol, a weight average molecular weight of 100,000 to 4,000,000g/mol, and a molecular weight distribution of 1.1 to 3.0.

9. The modified conjugated diene-based polymer according to claim 1, wherein the Mooney viscosity at 100 ℃ of the modified conjugated diene-based polymer is from 40 to 140.

10. A method for producing the modified conjugated diene-based polymer according to claim 1, which comprises:

1) preparing an organo-alkali metal compound as an initiator composition in a hydrocarbon solvent;

2) polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in the presence of the above initiator composition to prepare an active polymer; and

3) reacting the above living polymer with an aminosilane-based compound of the following formula 1:

[ formula 1]

In the formula 1, the first and second groups,

A¹and A²Each independently a substituted or unsubstituted divalent hydrocarbon group of 1 to 20 carbon atoms,

R¹to R⁴Each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms,

L¹to L⁴Each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms.

11. The method for producing a modified conjugated diene-based polymer according to claim 10, wherein the substituted styrene-based compound is used in an amount of 0.1 to 3.0 moles based on 1 mole of the organic-alkali metal compound.

12. The method for producing a modified conjugated diene-based polymer according to claim 10, wherein the aminosilane-based compound is used in an amount of 0.1 to 2.0 moles based on 1 mole of the organic-alkali metal compound.

13. A rubber composition comprising the modified conjugated diene-based polymer according to claim 1.

14. The rubber composition according to claim 13, wherein the rubber composition further comprises 0.1 to 150 parts by weight of a filler, based on 100 parts by weight of the modified conjugated diene-based polymer.

Technical Field

[ Cross-reference to related applications ]

The present application claims rights based on the priority of korean patent application No. 10-2016-.

Background

In accordance with recent demand for automobiles with low fuel consumption rates, conjugated diene-based polymers having modulation stability represented by wet skid resistance and low rolling resistance as well as excellent abrasion resistance and tensile properties are required as rubber materials for tires.

In order to reduce the rolling resistance of a tire, there is a method of reducing the hysteresis loss of a vulcanized rubber, and rebound resilience, tan, Goodrich heating (Goodrich heating) and the like at 50 to 80 ℃ are used as evaluation indexes of the vulcanized rubber. In other words, it is desirable to use rubber materials that have high resilience or low tan number or Goodrich heating at the above temperatures.

Natural rubber, polyisoprene rubber or polybutadiene rubber is known as a rubber material having low hysteresis loss, but these rubbers have a limitation of low wet skid resistance. Therefore, recently, conjugated diene-based (co) polymers such as styrene-butadiene rubber (hereinafter referred to as "SBR") and butadiene rubber (hereinafter referred to as "BR") are produced by emulsion polymerization or solution polymerization for use as rubber for tires. Among these polymerization methods, the solution polymerization has the greatest advantage over the emulsion polymerization that the vinyl structure content and styrene content, which determine the physical properties of the rubber, can be arbitrarily adjusted, and the molecular weight and physical properties thereof can be controlled by coupling or modification. Therefore, SBR prepared by solution polymerization is widely used as a rubber material for tires because it easily changes the structure of SBR or BR finally prepared, and by coupling or modification of chain ends, the movement of chain ends can be reduced and the coupling force with fillers such as silica and carbon black can be increased.

If the solution-polymerized SBR is used as a rubber material for tires, since the glass transition temperature of the rubber is increased as the vinyl content in the SBR increases, physical properties required for tires, such as running resistance and braking force, can be controlled, and fuel consumption can also be reduced by appropriately adjusting the glass transition temperature.

The solution-polymerized SBR is prepared by using an anionic polymerization initiator, and is used by coupling or modifying chain ends of the polymer thus formed using various modifiers. For example, U.S. patent No.4,397,994 discloses a method of coupling a living anion to the chain end of a polymer obtained by polymerizing styrene-butadiene using a monofunctional initiator alkyllithium in a nonpolar solvent using a binding agent such as a tin compound.

Meanwhile, as a material for a tire tread which comes into contact with the ground, a material having low rolling resistance and excellent wet grip and abrasion resistance which are sufficiently practical is required.

Conventionally, carbon black and silica are used as reinforcing fillers for tire treads, wherein if silica is used as a reinforcing filler, the advantages of low hysteresis loss and improved wet skid resistance can be obtained. However, since silica having a hydrophilic surface has a low affinity with a conjugated diene-based rubber as compared with carbon black having a hydrophobic surface and thus dispersibility is poor, it is necessary to use a separate silane coupling agent to improve dispersibility or to provide coupling between silica and rubber.

Therefore, attempts have been made to introduce a functional group having affinity or reactivity with silica into the terminal of a rubber molecule, and to reduce the movement of the terminal of the rubber molecule by coupling with silica particles, thereby improving the dispersibility of silica in a rubber composition and reducing hysteresis loss, but the effect thereof is insufficient.

Therefore, development of a rubber having high affinity with a filler such as silica is required.

Disclosure of Invention

Technical problem

The present invention is designed to solve the above-mentioned drawbacks of the conventional techniques, and an object of the present invention is to provide a modified conjugated diene-based polymer which exhibits excellent affinity with a filler in a rubber composition by including a functional group derived from a substituted styrene-based compound and a functional group derived from an aminosilane-based compound in the polymer.

Another object of the present invention is to provide a process for producing a modified conjugated diene-based polymer using a substituted styrene-based compound and an aminosilane-based compound.

It is still another object of the present invention to provide a rubber composition comprising the modified conjugated diene-based polymer.

Technical scheme

In order to solve the above-mentioned task, according to an embodiment of the present invention, there is provided a modified conjugated diene-based polymer comprising: a functional group derived from an aminosilane-based compound of the following formula 1:

[ formula 1]

In the formula 1, the first and second groups,

A¹and A²Each independently a substituted or unsubstituted divalent hydrocarbon group of 1 to 20 carbon atoms,

R¹to R⁴Each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms,

L¹to L⁴Each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms.

In addition, according to another embodiment of the present invention, there is provided a method for producing a modified conjugated diene-based polymer, comprising: preparing an organo-alkali metal compound as an initiator composition in a hydrocarbon solvent (step 1); polymerizing a conjugated diene monomer, or a conjugated diene monomer and an aromatic vinyl monomer in the presence of the initiator to prepare an active polymer (step 2); and reacting the living polymer with an aminosilane compound of the following formula 1 (step 3):

[ formula 1]

In the formula 1, the first and second groups,

A¹and A²Each independently a substituted or unsubstituted divalent hydrocarbon group of 1 to 20 carbon atoms,

R¹to R⁴Each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms,

L¹to L⁴Each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms.

According to still another embodiment of the present invention, there is provided a rubber composition comprising the modified conjugated diene-based polymer.

Advantageous effects

The modified conjugated diene-based polymer according to the present invention includes a functional group derived from the aminosilane-based compound of formula 1 at one end of the main chain, and can exhibit a high modification ratio. In particular, the polymer including tertiary amino groups derived from the aminosilane-based compound of formula 1 may exhibit excellent affinity with a filler when applied to a rubber composition. Therefore, aggregation of the filler in the rubber composition can be prevented, dispersibility of the filler can be improved, and processability of the rubber composition can be improved.

In addition, according to the method for preparing a modified conjugated diene-based polymer of the present invention, an initiator composition is obtained by preparing an organic-metal compound in a hydrocarbon solvent, a living polymer is formed by performing a polymerization reaction using the initiator composition, and a reaction is performed with the aminosilane-based compound of formula 1 to couple a functional group derived from the aminosilane-based compound to one end, thereby preparing a modified conjugated diene-based polymer having a functional group at one end of a main chain with a high modification ratio.

In addition, the rubber composition according to the present invention comprises the modified conjugated diene-based polymer and can improve the physical properties of the molded article produced, in particular, can improve the fuel consumption property, wear property and braking property in a tire in good balance.

Therefore, the modified conjugated diene-based polymer according to the invention, the production method thereof and the rubber composition comprising the modified conjugated diene-based polymer can be easily applied to industries requiring the modified conjugated diene-based polymer, for example, the tire industry.

Detailed Description

Hereinafter, the present invention will be described in more detail to help understanding the present invention.

It should be understood that the words or terms used in the specification and claims should not be construed as meaning defined in commonly used dictionaries. It should also be understood that these words or terms should be interpreted as having meanings consistent with their meanings in the technical idea of the present invention based on the principle that the inventor can appropriately define the meanings of the words or terms to best explain the present invention.

The term "monovalent hydrocarbon group" used in the present invention refers to a monovalent substituent derived from a hydrocarbon group, and may represent a carbon-to-hydrogen bonded monovalent radical, for example, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group containing at least one unsaturated bond, and an aryl group. The monovalent radical may have a linear or branched structure depending on its bonding structure.

The term "divalent hydrocarbon group" used in the present invention refers to a divalent substituent derived from a hydrocarbon group, and may represent a divalent radical in which carbon is bonded to hydrogen, for example, alkylene, alkenylene, alkynylene, cycloalkylene containing at least one unsaturated bond, and arylene. The divalent radical may have a linear or branched structure depending on its bonding structure.

The present invention provides a modified conjugated diene-based polymer having a high affinity with a filler and exhibiting excellent processability.

The modified conjugated diene-based polymer according to one embodiment of the present invention is characterized by comprising: a functional group derived from an aminosilane-based compound of the following formula 1:

[ formula 1]

In the formula 1, the first and second groups,

A¹and A²Each independently a substituted or unsubstituted divalent hydrocarbon group of 1 to 20 carbon atoms,

R¹to R⁴Each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms,

L¹to L⁴Each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms.

The modified conjugated diene-based polymer according to one embodiment of the present invention may be prepared by a preparation method described later, in which a functional group derived from the aminosilane-based compound of formula 1 may be coupled to one end of the main chain. In other words, the modified conjugated diene-based polymer according to the present invention may contain a functional group at one end, and thus, may exhibit a high modification rate and greatly improved physical properties.

In particular, in the aminosilane-based compound of formula 1 according to one embodiment of the present invention, an alkoxysilane structure is coupled to the active terminal of the conjugated diene-based polymer, and the Si — O-Si structure coupled to the terminal and two amino groups exhibit affinity with a filler such as silica, and thus, when compared with a conventional modifier containing one amino group in the molecule, the coupling of the filler with the modified conjugated diene-based polymer can be promoted. Further, since four alkoxy groups are coupled to adjacent Si-O-Si groups, when compared with a conventional modifier in which six alkoxy groups are coupled to Si-O-Si groups, the molecular weight can be easily controlled, and thus the molecular weight distribution of the conjugated diene-based polymer prepared is narrow, and the degree of coupling of the active terminal of the conjugated diene-based polymer is uniform. Therefore, when a change in the molecular weight distribution before and after coupling was observed, the molecular weight distribution after coupling was not increased but was constant as compared to before coupling. Therefore, the modified conjugated diene-based polymer itself shows no deterioration in physical properties, prevents aggregation of the filler in the rubber composition, and improves the dispersibility of the filler, thereby improving the processability of the rubber composition, in particular, the fuel consumption property, the wear property, and the braking property in a tire in a good balance.

In addition, the aminosilane-based compound of formula 1 may include an amino group, i.e., a tertiary amino group, which may prevent aggregation of the filler in the rubber composition and may improve dispersibility of the filler. For example, if silica is used as the filler, aggregation easily occurs due to hydrogen bonds between hydroxyl groups present on the surface thereof. In contrast, the tertiary amino group in the aminosilane-based compound suppresses the hydrogen bond between the hydroxyl groups, and the dispersibility of silica can be improved. Further, the aminosilane-based compound may contain: a functional group having an affinity with the filler, the functional group being capable of improving the abrasion resistance and processability of the rubber composition due to interaction with the filler together with the amino group; and a functional group having an affinity with a solvent, the functional group exhibiting an excellent affinity with a solvent used for a modification reaction of a polymer. The functional groups having affinity with the filler may in particular be alkoxysilane groups and, after incorporation into the polymer, undergo a condensation reaction with functional groups on the filler surface, for example silanol groups on the silica surface if the filler is silica, to improve the abrasion resistance and processability of the polymer. This improvement can be increased with increasing number of alkoxysilane groups. Further, the functional group having affinity with the solvent may be, in particular, a hydrocarbon group such as an alkyl group, and during the modification reaction of the polymer, the solubility of the aminosilane-based compound with respect to the solvent may be increased, and as a result, the modification ratio of the polymer may be increased.

In formula 1, A¹And A²May each be independently selected from the group consisting of substituted or unsubstituted alkylene of 1 to 20 carbon atoms, arylene of 6 to 20 carbon atoms, and combinations thereof. If A is¹Or A²Is a combination radical, in particular, may comprise- [ (X)_m-(Y)_n]- (wherein X and Y are each independently an alkylene group of 1 to 20 carbon atoms which may be substituted or unsubstituted, or an arylene group of 6 to 20 carbon atoms, X and Y are not identical, and m and n are each independently an integer of 1 to 3). More particularly, A¹And A²May each independently be 1 to 10 carbonsThe alkylene group of atoms, more specifically, may be an alkylene group of 1 to 6 carbon atoms, such as methylene, ethylene and propylene. The closer the distance between the Si atom and the N atom in the molecule, the better the effect, but if Si forms a direct bond with N, the bond is easily broken. As a result, the bond between Si and N is broken during the post-processing, and there is a high possibility that the secondary amino group thus produced is lost during the post-processing. Further, since there is no amino group which promotes the coupling with the silica filler, it is difficult to couple with the silica filler in the finally produced modified conjugated diene-based polymer, and as a result, the dispersing effect of the dispersant is deteriorated. As described above, in view of the excellent improvement effect according to the bond length between Si and N, A¹And A²May each independently be an alkylene group of 1 to 3 carbon atoms, such as methylene, ethylene and propylene, more particularly methylene and ethylene, still more particularly methylene.

In addition, A¹And A²May be each independently substituted with one or two or more substituents selected from the following substituents: an alkyl group of 1 to 10 carbon atoms, a cycloalkyl group of 3 to 10 carbon atoms, an alkoxy group of 1 to 10 carbon atoms, a cycloalkoxy group of 4 to 10 carbon atoms, an aryl group of 6 to 12 carbon atoms, an aryloxy group of 6 to 12 carbon atoms, an alkanoyloxy group of 2 to 12 carbon atoms (RaCOO —, wherein Ra is an alkyl group of 1 to 9 carbon atoms), an arylalkoxy group of 7 to 13 carbon atoms, an arylalkyl group of 7 to 13 carbon atoms, and an alkylaryl group of 7 to 13 carbon atoms, and more particularly, may be substituted with one or two or more substituents selected from the following substituents: alkyl of 1 to 4 carbon atoms, cycloalkyl of 3 to 6 carbon atoms, aryl of 6 to 8 carbon atoms, arylalkyl of 7 to 10 carbon atoms and alkylaryl of 7 to 10 carbon atoms, and still more particularly, may be substituted with alkyl of 1 to 4 carbon atoms.

In addition, in formula 1, R¹To R⁴May be each independently selected from the group consisting of substituted or unsubstituted alkyl groups of 1 to 20 carbon atoms, alkenyl groups of 2 to 20 carbon atoms, alkynyl groups of 2 to 20 carbon atoms, cycloalkyl groups of 3 to 20 carbon atoms, aryl groups of 6 to 20 carbon atoms, and aryl groups of 7 to 20 carbon atomsAn arylalkyl group of atoms and an alkylaryl group of 7 to 20 carbon atoms, and more particularly may be selected from the group consisting of substituted or unsubstituted alkyl groups of 1 to 10 carbon atoms, cycloalkyl groups of 3 to 10 carbon atoms, aryl groups of 6 to 12 carbon atoms, alkylaryl groups of 7 to 12 carbon atoms and arylalkyl groups of 7 to 12 carbon atoms. More particularly, R¹To R⁴May each independently be a substituted or unsubstituted alkyl group of 1 to 6 carbon atoms. Furthermore, R¹To R⁴Can be related to A¹And A²The substituents described.

In addition, in formula 1, L¹To L⁴May each independently be a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms, and specifically may be selected from a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, an alkenyl group of 2 to 20 carbon atoms, an alkynyl group of 2 to 20 carbon atoms, a cycloalkyl group of 3 to 20 carbon atoms, an aryl group of 6 to 20 carbon atoms, an arylalkyl group of 7 to 20 carbon atoms, and an alkylaryl group of 7 to 20 carbon atoms, and more specifically may be selected from a substituted or unsubstituted alkyl group of 1 to 10 carbon atoms, a cycloalkyl group of 3 to 10 carbon atoms, an aryl group of 6 to 12 carbon atoms, an alkylaryl group of 7 to 12 carbon atoms, and an arylalkyl group of 7 to 12 carbon atoms. More particularly, L¹To L⁴May each independently be a substituted or unsubstituted alkyl group of 1 to 6 carbon atoms. Furthermore, L¹To L⁴Can be related to A¹And A²The substituents described.

More particularly, the aminosilane compound of formula 1 may be A¹And A²Each independently an alkylene group of 1 to 3 carbon atoms, R¹To R⁴Each independently is an alkyl group of 1 to 6 carbon atoms, L¹To L⁴Each independently an alkyl group of 1 to 6 carbon atoms.

Still more specifically, the aminosilane-based compound of formula 1 may be a compound of the following formulae 1a to 1c, and one or a mixture of two of them may be used.

[ formula 1a ]

[ formula 1b ]

[ formula 1c ]

The aminosilane-based compound of formula 1 having the above structure may be directly prepared using a known chemical reaction, or may be commercially available.

In addition, the styrenic compound of formula 2 may comprise a functional group having an affinity with the filler, which is capable of improving the abrasion resistance and processability of the rubber composition by interacting with the filler.

In formula 2, R⁵May be a hydrogen atom or an alkyl group of 1 to 3 carbon atoms.

In addition, D in formula 2 may be a hydrocarbon group containing N or O in place of one or more carbon atoms, or a hydrocarbon group in which one or more hydrogen atoms bonded to a carbon atom are substituted with N or O.

In particular, D in formula 2 may be an alkyl group of 1 to 5 carbon atoms or a cycloalkyl group of 3 to 5 carbon atoms containing N or O.

In addition, in formula 2, k may be an integer of 0 to 5, and particularly, an integer of 2 to 3.

The modified conjugated diene-based polymer according to one embodiment of the present invention is characterized by comprising: a functional group derived from an aminosilane-based compound of the following formula 1 and a functional group derived from a substituted styrene-based compound of the following formula 2:

[ formula 1]

[ formula 2]

In the case of the formula 1 or the formula 2,

A¹and A²Each independently a substituted or unsubstituted divalent hydrocarbon group of 1 to 20 carbon atoms,

R¹to R⁴Each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms,

L¹to L⁴Each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms,

R⁵is a hydrogen atom or a monovalent hydrocarbon group of 1 to 3 carbon atoms,

d is a monovalent hydrocarbon group of 1 to 5 carbon atoms containing N or O,

k is an integer of 0 to 5.

The modified conjugated diene-based polymer according to one embodiment of the present invention may be prepared by a preparation method described below, in which a functional group derived from the substituted styrene-based compound of formula 2 may be coupled with one end of the main chain, and a functional group derived from the aminosilane-based compound of formula 1 may be coupled with the other end. That is, the modified conjugated diene-based polymer according to the present invention may include functional groups on both terminals, and thus, may exhibit a high modification rate and greatly improved physical properties.

More particularly, the substituted styrenic compound of formula 2 may be R⁵Is a hydrogen atom, D is an alkyl group of 1 to 3 carbon atoms or a cycloalkyl group of 3 to 5 carbon atoms containing N or O, and k is formula 2 of an integer of 2 to 3.

Still more particularly, the substituted styrenic compound of formula 2 may be a compound of formula 2a below.

[ formula 2a ]

The conjugated diene polymer may be a homopolymer of a conjugated diene monomer or a copolymer of a conjugated diene monomer and an aromatic vinyl monomer.

In addition, if the modified conjugated diene-based polymer is a copolymer, the copolymer may be a random copolymer in which structural units constituting the copolymer including a structural unit derived from a conjugated diene-based monomer and a structural unit derived from an aromatic vinyl-based monomer are randomly arranged and combined.

In particular, the modified conjugated diene-based polymer may have a narrow molecular weight distribution (Mw/Mn) (or referred to as polydispersity index (PDI)) of 1.1 to 3.0. When the molecular weight distribution of the modified conjugated diene-based polymer is more than 3.0 or less than 1.1, there is a fear that the tensile properties and viscoelasticity are deteriorated if the polymer is applied to a rubber composition. The molecular weight distribution of the modified conjugated diene-based polymer may be particularly 1.3 to 2.0 in consideration of a significant improvement effect in tensile properties and viscoelasticity of the polymer according to the control of the molecular weight distribution. Further, since the modified conjugated diene-based polymer uses a modifier, the molecular weight distribution can be similar to that of the conjugated diene-based polymer before modification.

In the present invention, the molecular weight distribution of the modified butadiene-based polymer can be calculated from the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn). In this case, the number average molecular weight (Mn) is a general average of the molecular weights of the individual polymers obtained by measuring the molecular weights of n polymer molecules, obtaining the sum of the molecular weights and dividing the sum by n. The weight average molecular weight (Mw) shows the molecular weight distribution of the polymer composition. The average of all molecular weights can be expressed in grams per mole (g/mol).

In the present invention, the weight average molecular weight and the number average molecular weight are molecular weights in terms of polystyrene analyzed by Gel Permeation Chromatography (GPC).

In addition, the modified conjugated diene-based polymer may satisfy the molecular weight distribution condition and have a number average molecular weight (Mn) of 50,000 to 2,000,000g/mol, more specifically, 200,000 to 800,000 g/mol. Further, the modified conjugated diene-based polymer may have a weight average molecular weight (Mw) of 100,000 to 4,000,000g/mol, more specifically, 300,000 to 1,500,000 g/mol.

If the weight average molecular weight (Mw) of the modified conjugated diene-based polymer is less than 100,000g/mol or the number average molecular weight (Mn) is less than 50,000g/mol, there is a fear that the tensile properties may deteriorate when the polymer is applied to a rubber composition. Further, if the weight average molecular weight (Mw) is more than 4,000,000g/mol or the number average molecular weight (Mn) is more than 2,000,000g/mol, the processability of the modified conjugated diene-based polymer may deteriorate, the workability of the rubber composition may deteriorate, and mixing and kneading may become difficult, whereby sufficient improvement of the physical properties of the rubber composition may become difficult.

More specifically, if the modified conjugated diene-based polymer according to one embodiment of the present invention satisfies both the conditions of the molecular weight distribution and the weight average molecular weight (Mw) and the number average molecular weight, when the polymer is incorporated into a rubber composition, the tensile properties, viscoelasticity and processability of the rubber composition can be improved in good balance without being biased toward one of them.

In addition, the vinyl content of the modified conjugated diene-based polymer may be 5% by weight or more, specifically 10% by weight or more, more specifically 10% by weight to 60% by weight, based on the total amount of the polymer. If the vinyl content is within the range, the glass transition temperature can be controlled within an appropriate range, and therefore, when the modified conjugated diene-based polymer is applied to a tire, the physical properties required for the tire, such as running resistance and braking force, can be improved.

In this case, the vinyl content represents the percentage of the amount of the repeating unit of the structure derived from the 1, 2-added conjugated diene-based monomer, not the 1, 4-addition, based on the total amount of the conjugated diene-based polymer composed of the vinyl-containing monomer or the conjugated diene-based monomer.

In addition, the modified conjugated diene-based polymer according to one embodiment of the present invention has a Mooney Viscosity (MV) at 100 ℃ of 40 to 140, specifically, 60 to 100. When the Mooney viscosity is within the above range, excellent processability can be obtained.

In the present invention, the mooney viscosity can be measured using a mooney viscometer, for example, MV2000E by Monsanto co., ltd., using a large rotor at a rotor speed of 2 ± 0.02rpm at 100 ℃. In this case, the sample used was left at room temperature (23. + -. 3 ℃ C.) for 30 minutes or more, and 27. + -.3 g of the sample was collected and put into the cavity, and then the Platen (Platen) was operated for measurement.

According to another embodiment of the present invention, there is provided a method for preparing a modified conjugated diene-based polymer using the aminosilane-based compound of formula 1 and a modification initiator composition comprising the substituted styrene-based compound of formula 2.

The production method according to an embodiment of the present invention is characterized by comprising: reacting the substituted styrene-based compound of formula 2 with an organo-alkali metal compound in a hydrocarbon solvent to prepare a modified initiator composition (step 1); polymerizing a conjugated diene monomer, or a conjugated diene monomer and an aromatic vinyl monomer in the presence of the modification initiator composition to prepare a living polymer (step 2); and reacting the living polymer with an aminosilane-based compound of formula 1 (step 3).

Step 1 is a step of preparing a modified initiator composition, and may be performed by reacting a substituted styrene-based compound with an organo-alkali metal compound in a hydrocarbon solvent. In this case, the modified initiator composition may contain a modified initiator compound having a structure in which an alkali metal derived from an organic-alkali metal compound is introduced into an oligomer of a substituted styrene-based compound.

The hydrocarbon solvent is not particularly limited, and may be, for example, at least one selected from the group consisting of n-pentane, n-hexane, n-heptane, isooctane, cyclohexane, toluene, benzene, and xylene.

The amount of the organo-alkali metal compound used may be 0.01mmol to 10mmol based on 100g of the total monomers. In particular, the organo-alkali metal compound may be used in an amount of 0.05mmol to 5mmol, more particularly, 0.1mmol to 3mmol, still more particularly, 0.1mmol to 2mmol, based on 100g of the monomer.

The organo-alkali metal compound is not particularly limited, but may be, for example, at least one selected from the group consisting of methyllithium, ethyllithium, propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, hexyllithium, n-decyllithium, tert-octyllithium, phenyllithium, 1-naphthyllithium, n-eicosyllithium, 4-butylphenyl lithium, 4-tolyllithium, cyclohexyllithium, 3, 5-di-n-heptylcyclohexylithium, 4-cyclopentyllithium, naphthylsodium, potassium naphthylate, lithium alkoxide, sodium alkoxide, potassium alkoxide, lithium sulfonate, sodium sulfonate, potassium sulfonate, lithium amide, sodium amide, potassium amide and lithium isopropylamide.

The substituted styrene-based compound may be used in an amount of 0.1 to 3.0 moles based on 1 mole of the organo-alkali metal compound.

Step 2 is a step of preparing a living polymer in which a functional group derived from a substituted styrene-based compound is coupled with an alkali metal, and may be performed by polymerizing a conjugated diene-based monomer, or an aromatic vinyl-based monomer with a conjugated diene-based monomer in the presence of a modification initiator composition.

In other words, in the production method according to one embodiment of the present invention, by polymerizing the monomers using the modification initiator composition, the polymer main chain can be formed, and at the same time, the functional group derived from the substituted styrene-based compound can be introduced into one end. Thus, the polymerization of step 2 may be the first modification step.

The polymerization in step 2 may use only the conjugated diene monomer, or may use the conjugated diene monomer together with the aromatic vinyl monomer as monomers. In other words, the polymer produced by the production method according to an embodiment of the present invention may be a homopolymer of the conjugated diene-based monomer, or a copolymer derived from the conjugated diene-based monomer and the aromatic vinyl-based monomer.

The conjugated diene monomer is not particularly limited, but may be, for example, at least one selected from the group consisting of 1, 3-butadiene, 2, 3-dimethyl-1, 3-butadiene, piperylene, 3-butyl-1, 3-octadiene, isoprene and 2-phenyl-1, 3-butadiene.

If the conjugated diene-based monomer and the aromatic vinyl-based monomer are used together as monomers, the conjugated diene-based monomer may be used in an amount such that the amount of the derived unit of the conjugated diene-based monomer in the finally prepared modified conjugated diene-based polymer is 60% by weight or more, specifically 60% by weight to 90% by weight, more specifically 60% by weight to 85% by weight.

The aromatic vinyl monomer is not particularly limited, but may be, for example, at least one selected from the group consisting of styrene, α -methylstyrene, 3-methylstyrene, 4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene, 4- (p-methylphenyl) styrene and 1-vinyl-5-hexylnaphthalene.

If the conjugated diene-based monomer and the aromatic vinyl-based monomer are used together as monomers, the aromatic vinyl-based monomer may be used in an amount such that the amount of the derived unit of the aromatic vinyl-based monomer in the finally produced modified conjugated diene-based polymer is 40% by weight or less, specifically 10% by weight to 40% by weight, more specifically 15% by weight to 40% by weight.

The reaction of step 1 and the polymerization of step 2 may be respectively carried out by further adding a polar additive according to need, and the added amount of the polar additive may be 0.001 to 1.0 parts by weight based on 100 parts by weight of the total monomers. Specifically, the addition amount may be 0.005 to 0.5 parts by weight, more specifically, 0.01 to 0.3 parts by weight, based on 100 parts by weight of the monomer.

The polar additive may be at least one selected from the group consisting of tetrahydrofuran, 2-bis (2-tetrahydrofuryl) propane, diethyl ether, cyclopentyl ether, dipropyl ether, ethylene dimethyl ether, ethylene glycol, dimethyl ether, t-butoxyethoxyethane, bis (3-dimethylaminoethyl) ether, (dimethylaminoethyl) ethyl ether, trimethylamine, triethylamine, tripropylamine, and tetramethylethylenediamine.

In the preparation method according to one embodiment of the present invention, if the conjugated diene-based monomer and the aromatic vinyl-based monomer are copolymerized, the difference in reaction rate therebetween may be compensated by adding the polar additive, thereby inducing easy formation of the random copolymer.

The polymerization of step 2 may be carried out by adiabatic polymerization or isothermal polymerization.

Here, adiabatic polymerization refers to a polymerization method comprising a step of performing polymerization using heat generated by the reaction itself without optionally supplying heat after adding an organic-alkali metal compound. Isothermal polymerization refers to a polymerization method in which the temperature of a polymer is kept constant by optionally supplying or removing heat after addition of an organic-alkali metal compound.

The polymerization can be carried out at a temperature in the range of-20 ℃ to 200 ℃, specifically, 0 ℃ to 150 ℃, more specifically, 10 ℃ to 120 ℃.

Step 3 is a step of reacting the living polymer with an aminosilane-based compound of formula 1 to prepare a modified conjugated diene-based polymer.

In this case, the aminosilane-based compound of formula 1 may be used in a ratio of 0.1 mol to 2.0 mol with respect to 1 mol of the organo-alkali metal compound.

The reaction of step 3 is a modification reaction in which a functional group is introduced into a polymer, and each reaction may be performed at a temperature ranging from 0 ℃ to 90 ℃ for 1 minute to 5 hours.

The preparation method according to an embodiment of the present invention may further include at least one step of recovering and drying the solvent and the unreacted monomer after step 3, as necessary.

In addition, according to another embodiment of the present invention, there is provided a rubber composition comprising the modified conjugated diene-based polymer.

The rubber composition comprises the modified conjugated diene-based polymer, and can improve the physical properties of molded articles, in particular, can improve the fuel consumption properties, wear properties and braking properties in tires in a good balance.

In particular, the rubber composition may contain 0.1 to 100% by weight, specifically 10 to 100% by weight, more specifically 20 to 90% by weight of the modified conjugated diene-based polymer. If the amount of the modified conjugated diene-based polymer is less than 0.1% by weight, the effect of improving the fuel consumption property, the abrasion resistance and the braking property of a molded article, for example, a tire, produced by using the rubber composition may not be significant.

In addition, the rubber composition may contain other rubber components in addition to the modified conjugated diene-based polymer as required, and in this case, the content of the rubber component may be 90% by weight or less based on the total amount of the rubber composition. Specifically, the content of the rubber component may be 1 part by weight to 900 parts by weight based on 100 parts by weight of the modified conjugated diene-based copolymer.

The rubber component may be a natural rubber or a synthetic rubber, and the rubber component may be, for example, a Natural Rubber (NR) including cis-1, 4-polyisoprene; modified natural rubbers obtained by modifying or purifying conventional natural rubbers, such as Epoxidized Natural Rubber (ENR), deproteinized natural rubber (DPNR), and hydrogenated natural rubber; and synthetic rubbers such as styrene-butadiene copolymer (SBR), polybutadiene (BR), polyisoprene (IR), butyl rubber (IIR), ethylene-propylene copolymer, polyisobutylene-co-isoprene, chloroprene rubber, poly (ethylene-co-propylene), poly (styrene-co-butadiene), poly (styrene-co-isoprene), poly (styrene-co-isoprene-co-butadiene), poly (ethylene-co-propylene-co-diene), polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, butyl rubber, and halogenated butyl rubber, and any one of them or a mixture of at least two of them may be used.

In addition, the rubber composition may contain 0.1 to 150 parts by weight of a filler, based on 100 parts by weight of the modified conjugated diene-based polymer.

The filler may be particularly a silica-based filler or a carbon black-based filler, and one or a mixture of both of them may be used.

More particularly, the filler may be silica, still more particularly wet-process silica (hydrated silicate), dry-process silica (anhydrous silicate), calcium silicate, aluminum silicate or colloidal silica. More particularly, the filler may be wet silica having the most significant effect of improving the breaking characteristics and the compatible effect of wet-road adhesion.

Meanwhile, if a silica-based filler is used as the filler, a silane coupling agent may be used together to improve the reinforcing and low heat release properties.

The silane coupling agent may specifically include: bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, and mixtures thereof, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzoyl tetrasulfide, 3-triethoxysilylpropylmethacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide or dimethoxymethylsilylpropylbenzothiazolyl tetrasulfide, and any one or a mixture of at least two thereof may be used. More specifically, the silane coupling agent may be bis (3-triethoxysilylpropyl) polysulfide or 3-trimethoxysilylpropyl benzothiazolyl tetrasulfide, in view of the effect of improving the performance.

In addition, in the rubber composition according to one embodiment of the present invention, since the modified conjugated diene-based polymer having a functional group having a high affinity with the silica-based filler introduced at the active site is used as the rubber component, the blending amount of the silane coupling agent can be smaller than that in the conventional case. In particular, the silane coupling agent may be used in an amount of 1 to 20 parts by weight, based on 100 parts by weight of the silica-based filler. When the amount is within the above range, the effect as a coupling agent can be sufficiently exhibited, and gelation of the rubber component can be prevented. More particularly, the silane coupling agent may be used in an amount of 5 parts by weight to 15 parts by weight, based on 100 parts by weight of silica.

In addition, the rubber composition according to one embodiment of the present invention may be sulfur-crosslinkable and, therefore, may further contain a vulcanizing agent.

The vulcanizing agent may be, in particular, sulfur powder, and may be contained in an amount of 0.1 parts by weight to 10 parts by weight, based on 100 parts by weight of the rubber component. The amount within the above range can ensure the elasticity and strength required for the vulcanized rubber composition, and at the same time, can realize a low fuel consumption rate.

In addition, the rubber composition according to one embodiment of the present invention may further include various additives used in the conventional rubber industry, in particular, a vulcanization accelerator, a processing oil, a plasticizer, an age resistor, an anti-scorching agent, zinc white, stearic acid, a thermosetting resin, or a thermoplastic resin, in addition to the above-mentioned ingredients.

The vulcanization accelerator is not particularly limited, and may specifically include: thiazole compounds, such as 2-mercaptobenzothiazole (M), dibenzothiazyl Disulfide (DM) and N-cyclohexyl-2-benzothiazylsulfenamide (CZ); or a guanidine compound such as Diphenylguanidine (DPG). The content of the vulcanization accelerator may be 0.1 parts by weight to 5 parts by weight based on 100 parts by weight of the rubber component.

In addition, the processing oil functions as a softener in the rubber composition, and may particularly include paraffins, naphthenes, or aromatic compounds. More specifically, an aromatic processing oil may be used in consideration of tensile strength and abrasion resistance, and a naphthenic or paraffinic processing oil may be used in consideration of hysteresis loss and low-temperature properties. The processing oil may be included in an amount of 100 parts by weight or less based on 100 parts by weight of the rubber component. Within the above amount range, the deterioration of the tensile strength and low heat release performance (low fuel consumption rate) of the vulcanized rubber can be prevented.

In addition, the age resister may specifically include N-isopropyl-N '-phenyl-p-phenylenediamine, N- (1, 3-dimethylbutyl) -N' -phenyl-p-phenylenediamine, 6-ethoxy-2, 2, 4-trimethyl-1, 2-dihydroquinoline or a condensate of diphenylamine with acetone at a high temperature. The age resistor may be used in an amount of 0.1 parts by weight to 6 parts by weight, based on 100 parts by weight of the rubber component.

The rubber composition according to one embodiment of the present invention can be obtained by mixing according to the mixing formulation using mixing devices such as a Banbury mixer, rolls, and an internal mixer. Further, a rubber composition having low heat release properties and good abrasion properties can be obtained by a vulcanization treatment after the molding process.

Thus, the rubber composition can be used for producing various members of a tire, such as a tire tread, a tread base, a sidewall, a carcass coating rubber, a belt coating rubber, a bead filler and a bead coating rubber, or for producing rubber products in various industries, such as a dust-proof rubber, a conveyor belt and a hose.

In addition, according to another embodiment of the present invention, there are provided a molded article and a tire prepared using the rubber composition.

Hereinafter, the present invention will be described in more detail with reference to examples and experimental examples. However, the following examples and experimental examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.