Modified vinyl aromatic copolymer and method for producing the same, modified conjugated diene copolymer, and applications thereof

Abstract

The present invention provides a modified vinyl aromatic copolymer and a method for producing the same, a modified conjugated diene copolymer, and applications thereof. The modified vinyl aromatic copolymer is characterized in that it contains a structural unit (a) derived from a divinyl aromatic compound and a structural unit (b) derived from a monovinyl aromatic compound, at least a portion of the structural unit (a) is a crosslinking structural unit (a1) described below, and the terminal of the modified vinyl aromatic copolymer is modified with a modifying group, and the modifying group has at least one functional group selected from the group consisting of an amino group, a hydroxyl group, and an alkoxysilyl group.

Description

Technical Field

[0001] The present invention relates to a modified vinyl aromatic copolymer having excellent reactivity in a reaction with an active (living) end of a conjugated diene polymer using an organic lithium compound as an initiator in a hydrocarbon solvent and a method for producing the same. In addition, the present invention relates to a modified vinyl aromatic copolymer having a branched structure and a method for producing the same. In addition, the present invention relates to a modified conjugated diene copolymer having excellent processability and excellent tensile strength and wear resistance, a modified conjugated diene copolymer composition containing the modified conjugated diene copolymer, a rubber cross-linked product obtained by cross-linking the modified conjugated diene copolymer composition, and a tire component. Background Art

[0002] Conjugated diene rubbers such as styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), and styrene-isoprene rubber have excellent wear resistance, elasticity, and water resistance, and are therefore used in various applications such as molding materials and resin modifiers.

[0003] One of the main uses of the conjugated diene rubber is automobile tires. The properties required in tires include mechanical strength, wear resistance, wet grip resistance, etc. (hereinafter also referred to as strength, etc.). Furthermore, in recent years, the development of tires with excellent energy-saving performance, i.e., low fuel consumption (so-called eco tires) has become active. The eco tires are required not only to have strength, etc., but also to have low rolling resistance.

[0004] In order to ensure the strength of the tire, it is known to add fillers such as carbon black or silica (reinforcement fillers) in conjugated diene rubber, but as a material that further improves the strength of the tire and imparts excellent rolling resistance, end-modified solution polymerization type SBR (end-modified S-SBR) has attracted much attention. End-modified S-SBR has a functional group at the molecular end of SBR, and the functional group at the molecular end interacts with the filler. Through the interaction, the dispersibility of the filler in SBR is improved, and the molecular end of SBR is constrained, and mobility is reduced. As a result, the hysteresis loss (hysteresis loss) (internal friction) of the tire is reduced, and rolling resistance is reduced. Effectively utilizing the characteristics, the development of an eco-tire having both strength and low rolling resistance has been carried out.

[0005] For example, in Patent Document 1, a block copolymer including an α-methylstyrene block and a butadiene block is synthesized by living anionic polymerization using an organic lithium compound as an initiator in a non-polar solvent, and a multifunctional coupling agent is reacted as needed to obtain an S-SBR having both high temperature characteristics and rubber properties.

[0006] In addition, Patent Document 2 discloses a star-block interpolymer having a random copolymer block of a conjugated diene and a monovinyl aromatic monomer, a polyconjugated diene block, and a functional group derived from a multifunctional lithium-based initiator, and discloses that the rubber can be widely used to make tire treads having excellent properties such as reduced rolling resistance and improved traction properties.

[0007] The technologies of Patent Documents 1 and 2 are believed to have the effect of ensuring the processability of rubber by introducing a branched structure into the rubber component, but no special design is made for the interaction with the filler for ensuring strength, and the contribution to strength is insufficient.

[0008] In addition, Patent Document 3 discloses a rubber composition, which is a rubber composition in which a predetermined amount of carbon black is blended into a mixed rubber containing a plurality of diene rubbers, and a polymer containing a low molecular weight functional group having a functional group that interacts with carbon black and a polymer structure similar to the rubber component of the diene rubber is blended at the end of the molecular chain. The rubber composition can control the amount of carbon black distributed to each diene rubber component by blending a low molecular weight compound that interacts with carbon black into the rubber. Therefore, the strengths of each rubber component can be effectively expressed, and a balance of rubber properties that are in an opposite relationship, such as rolling characteristics and wet characteristics, can be achieved. However, the technology blends low molecular weight compounds into rubber, and therefore is not sufficient in terms of contribution to strength.

[0009] In addition, in Patent Document 4, a crosslinked rubber particle comprising a conjugated diene unit, an aromatic vinyl unit and a unit having at least two polymerizable unsaturated groups, and a rubber composition containing a conjugated diene / aromatic vinyl copolymer rubber containing a conjugated diene unit having a specific bonding structure are disclosed, and it is disclosed that the crosslinked rubber particle may contain a monomer unit having a carboxylic acid group, a hydroxyl group and / or an epoxy group. The technology has a moderate interaction with inorganic fillers (fillers) such as silica, so the dispersibility and processability of the inorganic filler are excellent. However, the substances disclosed as monomer units having at least two polymerizable unsaturated groups or monomer units having carboxylic acid groups, hydroxyl groups and / or epoxy groups are all low molecular weight. Therefore, the reactivity is too high, and there is a risk of gelation in the crosslinked rubber particles and rubber compositions. In addition, the technology must be used to independently synthesize the crosslinked rubber with the conjugated diene / aromatic vinyl copolymer rubber, and then the crosslinked rubber is blended with the conjugated diene / aromatic vinyl copolymer rubber, which needs to be improved from the perspective of the simplicity of the steps.

[0010] In view of the above problems, the present applicants have found that a copolymer rubber having both processability, strength and homogeneity can be provided by using a specific multifunctional vinyl aromatic copolymer compound having both a branched structure and an interactive function with a filler as a constituent unit of a conjugated diene rubber (Patent Document 5).

[0011] However, although the gelation of the polyfunctional vinyl aromatic copolymer compound is greatly improved, there is still a problem of incidentally generating a small amount of microgel.

[0012] Furthermore, the applicant has disclosed similar compounds to the polyfunctional vinyl aromatic copolymer compound disclosed in Patent Document 5 in Patent Document 6, Patent Document 7, etc. However, there is no teaching on using these similar compounds as constituent units of copolymer rubber.

[0013] Furthermore, the multifunctional vinyl aromatic copolymer disclosed in Patent Document 8 is a copolymer having a wide molecular weight distribution and including a large number of high molecular weight entities with significantly developed branched structures. Therefore, when used as a constituent unit of a copolymer rubber, there is a problem of incidentally generating a small amount of microgel.

[0014] Prior art literature

[0015] Patent Literature

[0016] Patent Document 1: Japanese Patent Application Publication No. 2003-73434

[0017] Patent Document 2: Japanese Patent Publication No. 2004-517202

[0018] Patent Document 3: Japanese Patent Application Publication No. 2005-213381

[0019] Patent Document 4: International Publication No. 2002 / 000779

[0020] Patent Document 5: International Publication No. 2018 / 084128

[0021] Patent Document 6: Japanese Patent Application Publication No. 2004-123873

[0022] Patent Document 7: Japanese Patent Application Publication No. 2018-39995

[0023] Patent Document 8: International Publication No. 2018 / 181842 Summary of the invention

[0024] The present invention aims to solve the above-mentioned problems and to provide a modified vinyl aromatic copolymer which does not generate a small amount of microgel and has reactivity and solubility that can be used for the production of a modified conjugated diene copolymer, a modified conjugated diene copolymer composition having both processability, strength and homogeneity, a rubber cross-linked product obtained by cross-linking the modified conjugated diene copolymer composition, and a tire member.

[0025] The inventors have repeatedly conducted diligent research and found that a copolymer formed by modifying the active ends of a branched vinyl aromatic copolymer containing a specific structural unit (a) derived from a divinyl aromatic compound and a structural unit (b) derived from a monovinyl aromatic compound with an amino group, an alkoxysilane group or a hydroxyl group can solve the above-mentioned problem, thereby completing the present invention. In addition, it was found that a modified vinyl aromatic copolymer formed by modifying the side chain or the end of a multifunctional vinyl aromatic copolymer with a silane compound has high reactivity when manufacturing a modified conjugated diene copolymer, and the above-mentioned problem is solved by using the modified conjugated diene copolymer as a constituent unit of a modified conjugated diene copolymer composition, thereby completing the present invention.

[0026] The present invention is a modified vinyl aromatic copolymer comprising a structural unit (a) derived from a divinyl aromatic compound and a structural unit (b) derived from a monovinyl aromatic compound, wherein at least a part of the structural unit (a) of the modified vinyl aromatic copolymer is a crosslinking structural unit (a1) as described below:

[0027] [Chemistry 1]

[0028]

[0029] (Here, R 1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms), and

[0030] One or more terminals of the modified vinyl aromatic copolymer are modified with a modifying group, and the modifying group includes at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group.

[0031] The present invention also provides a modified vinyl aromatic copolymer, which is a copolymer comprising a structural unit (a) derived from a divinyl aromatic compound and a structural unit (b) derived from a monovinyl aromatic compound, wherein the copolymer comprises 0.5 mol% to 95.0 mol% of the structural unit (a) and 5.0 mol% to 99.5 mol% of the structural unit (b) relative to the total of the structural unit (a) and the structural unit (b);

[0032] The copolymer contains one or more silane functional groups (c) represented by the following formula (c1) or formula (c2) on the side chain or at the terminal,

[0033] [Chemistry 2]

[0034]

[0035] (Here, R 2 is a divalent alkylene group having 1 to 6 carbon atoms, R 3 , R 4 , R 5 , R 7 , R 8 and R 9 Each independently represents a methoxy group, an ethoxy group, a propoxy group, a butoxy group, an octyloxy group, a lauryl group, a phenoxy group, a benzyloxy group, a methyl group, an ethyl group, a propyl group, a butyl group, a cyclohexyl group, a phenyl group, or a benzyl group, wherein R 3 , R 4 and R 5 At least one of, or R 7 , R 8 and R 9 at least one of which is methoxy, ethoxy, propoxy, butoxy, octyloxy, lauryloxy, phenoxy, or benzyloxy),

[0036] The molar fraction of the crosslinking structural unit (a1) relative to the structural unit (a) is in the range of 0.05 to 0.90,

[0037] Each molecule has 1 to 20 silane functional groups (c),

[0038] The number average molecular weight Mn is 500 to 100,000, and the molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight Mw to the number average molecular weight Mn is 30.0 or less.

[0039] The modified vinyl aromatic copolymer may include one or more copolymers represented by any one of the following formulae (2) to (13):

[0040] [Chemistry 3]

[0041]

[0042]

[0043] [Chemistry 4]

[0044]

[0045] (Where R 2 is a divalent alkylene group having 1 to 6 carbon atoms, R 3 , R 4 , and R 5 Same as the above formula (c1), R 6 is an alkyl group having 1 to 6 carbon atoms, a vinyl group or hydrogen, a polymer is a copolymer chain, and R 7 , R 8 , and R 9 The same meaning as the above formula (c2). The benzene ring in the formula may be any aromatic ring).

[0046] As the structural unit (b) derived from a monovinyl aromatic compound, the following structural units can be listed, that is, structural units derived from one or more monomers selected from the group consisting of styrene, vinylnaphthalene, vinylbiphenyl, m-methylstyrene, p-methylstyrene, o-, p-dimethylstyrene, m-ethylvinylbenzene, indene and p-ethylvinylbenzene.

[0047] In addition, the present invention is a method for producing a modified vinyl aromatic copolymer, which is a method for producing the modified vinyl aromatic copolymer from a multifunctional vinyl aromatic copolymer and a silane compound, wherein

[0048] The polyfunctional vinyl aromatic copolymer is a polyfunctional vinyl aromatic copolymer comprising 0.5 mol% or more and 95.0 mol% or less of a structural unit (a) derived from a divinyl aromatic compound, 5.0 mol% or more and 99.5 mol% or less of a structural unit (b) derived from a monovinyl aromatic compound, and

[0049] At least a part of the structural unit (a) is the crosslinking structural unit (a1) and the following vinyl-containing structural unit (a2),

[0050] [Chemistry 5]

[0051]

[0052] (Where R 1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms),

[0053] The molar fraction of the crosslinking structural unit (a1) relative to the structural unit (a) is in the range of 0.05 to 0.90,

[0054] The molar fraction of the vinyl-containing structural unit (a2) relative to the total of the structural unit (a) and the structural unit (b) is in the range of 0.001 to 0.80,

[0055] Mn is 300 to 50,000, Mw / Mn is 20.0 or less,

[0056] The silane compound is a silane compound represented by the following formula (15) and / or formula (16),

[0057] [Chemistry 6]

[0058]

[0059] (Here, R 2 , R 3 , R 4 and R 5 Same as the above formula (c1), R 6 , R 7 and R 8 R of the formula (c2) 7 , R 8 and R 9 Synonymous.)

[0060] The polyfunctional vinyl aromatic copolymer and the silane compound are dissolved in a hydrocarbon solvent and added at a temperature of 0° C. to 150° C. in the presence of a catalyst.

[0061] In addition, the present invention is a modified conjugated diene copolymer obtained by reacting the modified vinyl aromatic copolymer (A) as a modifier with a polymer of a conjugated diene compound (B) having an active terminal, or a copolymer of a conjugated diene compound (B) having an active terminal and an aromatic vinyl compound (C).

[0062] The modified conjugated diene copolymer may contain 0.001 wt % to 6 wt % of a structural unit (A1) derived from a modified vinyl aromatic copolymer (A), 29 wt % to 99.999 wt % of a structural unit (B1) derived from a conjugated diene compound (B), and 0 wt % to 70 wt % of a structural unit (C1) derived from an aromatic vinyl compound (C). In addition, in a differential molecular weight distribution curve obtained by gel permeation chromatography (GPC), when the total area is set to 100%, the area of ​​a region having a number average molecular weight (Mn) that is three times or more of the peak value on the lowest molecular weight side is 10% or more.

[0063] In addition, the present invention is a modified conjugated diene copolymer composition, wherein a filler or a reinforcing filler is formulated in the modified conjugated diene copolymer, and the reinforcing filler is at least one selected from the group consisting of a silica-based inorganic filler, a metal oxide, a metal hydroxide and carbon black, and the composition may further contain a crosslinking agent.

[0064] The present invention also provides a cross-linked rubber obtained by cross-linking the modified conjugated diene copolymer composition. The present invention also provides a tire member including the cross-linked rubber.

[0065] Furthermore, the present invention is a modified vinyl aromatic copolymer, comprising a structural unit (a) derived from a divinyl aromatic compound and a structural unit (b) derived from a monovinyl aromatic compound, wherein 95 mol % or more of the structural unit (a) is the crosslinking structural unit (a1), and

[0066] Two or more terminals of the modified vinyl aromatic copolymer are modified with a modifying group, and the modifying group has at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group.

[0067] The modified vinyl aromatic copolymer preferably satisfies any one or more of the following: relative to the total of the structural units (a) and the structural units (b), it contains 0.5 mol% to 95.0 mol% of the structural units (a) and 5.0 mol% to 99.5 mol% of the structural units (b); the number average molecular weight Mn is 500 to 50,000, and the molecular weight distribution (Mw / Mn) is less than 10.0; the average number of functional groups per molecule is in the range of 2 to 20; or the monovinyl aromatic compound is one or more monomers selected from the group consisting of styrene, vinylnaphthalene, vinylbiphenyl, m-methylstyrene, p-methylstyrene, o-, p-dimethylstyrene, m-ethylvinylbenzene, indene and p-ethylvinylbenzene.

[0068] In addition, the present invention is a method for producing the modified vinyl aromatic copolymer, which comprises: a polymerization step, using an alkali metal compound or an alkaline earth metal compound as an anionic polymerization initiator to copolymerize a divinyl aromatic compound and a monovinyl aromatic compound, or a divinyl aromatic compound and a monovinyl aromatic compound with a monomer capable of anion copolymerization with these compounds, to obtain a vinyl aromatic copolymer having a branched structure and an active terminal; and a terminal modification step, reacting a compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group, or a precursor compound of these groups, with the active terminal of the vinyl aromatic copolymer to form a functional group.

[0069] The present invention also provides a modified conjugated diene copolymer obtained by reacting the modified vinyl aromatic copolymer with a polymer of a conjugated diene compound or a copolymer of a conjugated diene compound and an aromatic vinyl compound.

[0070] The modified conjugated diene copolymer preferably contains: 0.001 wt % to 6 wt % of a structural unit (A1) derived from a modified vinyl aromatic copolymer, 29 wt % to 99.999 wt % of a structural unit (B1) derived from a conjugated diene compound, and 0 wt % to 70 wt % of a structural unit (C1) derived from an aromatic vinyl compound; or in a differential molecular weight distribution curve obtained by GPC measurement, when the total area is set to 100%, the area of ​​the region having a number average molecular weight (Mn) of more than 3 times the peak value on the lowest molecular weight side is more than 10%.

[0071] Furthermore, the present invention is a rubber composition, which contains 0.5 to 200 parts by weight of at least one reinforcing filler selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides and carbon black, relative to 100 parts by weight of the modified conjugated diene copolymer, and the rubber composition may also contain a cross-linking agent.

[0072] The present invention also provides a cross-linked rubber product obtained by cross-linking the rubber composition, and a tire component including the cross-linked rubber product.

[0073] Effects of the Invention

[0074] The modified vinyl aromatic copolymer of the present invention can be used as the raw material of modified conjugated diene copolymer. And then, the crosslinked rubber composition formed by crosslinking and containing filler in the modified conjugated diene copolymer can be effectively used as elastomeric materials such as tire (particularly tire tread (tyretread)), shock-absorbing rubber, rubber hose, rubber roller, footwear material because of the excellent dispersibility, mechanical strength and wear resistance of filler. In addition, it can be applied to the improver of molding material, resin, etc. In the fields such as electrical-electronic industry, aerospace industry, it can be provided as dielectric material, insulating material, heat-resistant material, structural material, etc.

[0075] In addition, films and sheets coated with a curable resin composition containing the modified vinyl aromatic copolymer of the present invention can be suitably used for plastic optical parts, touch panels, flat panel displays, film liquid crystal elements, etc., and can also be used as a modifier for improving the heat resistance, dielectric properties, optical properties, etc. of thermoplastic resins or curable resin compositions used as the main materials of films, sheets, and prepregs. In addition, the curable resin composition can be processed into films, sheets, and prepregs for use, and can also be used as various optical elements such as optical waveguides and optical lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 This is a GPC chart of the modified conjugated diene copolymer. DETAILED DESCRIPTION

[0077] The modified vinyl aromatic copolymer of the present invention (hereinafter also referred to as modified copolymer or copolymer) is a modified vinyl aromatic copolymer containing structural units (a) derived from divinyl aromatic compounds and structural units (b) derived from monovinyl aromatic compounds, wherein at least a portion of the structural units (a) are the cross-linking structural units (a1), and one or more, preferably one or more, terminals of the copolymer are modified with a modifying group, and the modifying group comprises at least one functional group selected from the group consisting of an amino group, a hydroxyl group and an alkoxysilyl group.

[0078] The modified vinyl aromatic copolymer modified with a modifying group containing an alkoxysilyl group (hereinafter also referred to as a modified copolymer or copolymer A) is described. (First Form)

[0079] The modified vinyl aromatic copolymer contains 0.5 mol% to 95.0 mol% of a structural unit (a) derived from a divinyl aromatic compound and 5.0 mol% to 99.5 mol% or less of a structural unit (b) derived from a monovinyl aromatic compound, and contains the crosslinking structural unit (a1) as at least a part of the structural unit (a).

[0080] In addition, the copolymer has an alkoxysilyl group represented by the formula (c1) or the formula (c2) at the side chain or the terminal. 3 , R 4 , R 5 At least one or R 7 , R 8 , R 9 At least one of the groups is an alkoxy group. Here, the alkoxy group is a group represented by RO-, and R is an alkyl group, an aralkyl group, or an aryl group, but is preferably a C1-12 alkyl group, a benzyl group, or a phenyl group.

[0081] Since the alkoxysilyl group is a silane-based functional group, it is also referred to as a silane-based functional group (c) or a structural unit (c).

[0082] The number average molecular weight Mn of the modified vinyl aromatic copolymer is 500 to 100,000, and Mw / Mn is 30.0 or less.

[0083] The molar fraction of the crosslinking structural unit (a1) in the structural unit (a) is in the range of 0.05 to 0.90, and the number of the structural unit (c) per molecule is in the range of 1 to 20, preferably 2 to 20.

[0084] The molar fraction (also referred to as the degree of crosslinking) of the crosslinked structural unit (a1) relative to the structural unit (a) is in the range of 0.05 to 0.90, but the preferred lower limit is 0.06, and more preferably 0.07. In addition, the preferred upper limit is 0.80, and more preferably 0.70. Particularly preferably, it is 0.60, and most preferably 0.50. The most suitable range is 0.20 to 0.50. If the molar fraction is less than 0.05, since the degree of crosslinking of the copolymer is small, when the structural unit (c) is introduced, it is easy to cause a crosslinking reaction within the molecule of the copolymer, and there is a tendency to generate microgels when copolymerized with conjugated diene compounds, etc. On the other hand, if it is greater than 0.90, the molecular weight of the copolymer itself increases, and the molecular weight distribution tends to become wider, so the wear resistance tends to decrease.

[0085] The modified vinyl aromatic copolymer of the present invention can be obtained by reacting an unmodified multifunctional vinyl aromatic copolymer with the silane compound represented by the formula (15) and / or the formula (16).

[0086] In formula (15) and formula (16), R 2 is a divalent alkylene group having 1 to 6 carbon atoms, R 3 , R 4 , R 5 , R 6 , R 7 and R 8Each independently represents a methoxy group, an ethoxy group, a propoxy group, a butoxy group, an octyloxy group, a lauryl group, a phenoxy group, a benzyloxy group, a methyl group, an ethyl group, a propyl group, a butyl group, a cyclohexyl group, a phenyl group, or a benzyl group. 3 , R 4 and R 5 At least one of the above may be a methoxy group, an ethoxy group, a propoxy group, a butoxy group, an octyloxy group, a lauryloxy group, a phenoxy group, or a benzyloxy group.

[0087] As the silane compound represented by the formula (15), for example, there can be mentioned: mercapto methylene methyl diethoxy silane, mercapto methylene triethoxy silane, 2-mercapto ethyl trimethoxy silane, 2-mercapto ethyl triethoxy silane, 2-mercapto ethyl methoxy dimethyl silane, 2-mercapto ethyl ethoxy dimethyl silane, 3-mercapto propyl trimethoxy silane, 3-mercapto propyl triethoxy silane, 3-mercapto propyl dimethoxy methyl silane, 3-mercapto propyl diethoxy methyl silane, 3-mercapto propyl dimethoxy ethyl silane, 3-mercapto propyl diethoxy ethyl silane, 3-mercapto propyl methoxy dimethyl silane, 3-mercapto propyl ethoxy dimethyl silane, etc. These silane compounds can be used alone or in combination of two or more.

[0088] By a free radical addition reaction between the mercapto group (-SH) of the silane compound represented by the formula (15) and the carbon-carbon unsaturated bonds contained in the multifunctional vinyl aromatic copolymer, a modified vinyl aromatic copolymer represented by the formulas (2) to (7) having a structural unit (c) derived from the silane compound is obtained.

[0089] As the silane compound represented by the formula (16), for example, trimethoxysilane, triethoxysilane, dimethoxymethylsilane, dimethoxychloromethylsilane, methoxydimethylsilane, dimethoxyphenylsilane, 1,3,3,5,5,7,7-heptamethyl-1,1-dimethoxytetrasiloxane and other alkoxysilanes can be listed. These silane compounds can be used alone or in combination of two or more. Among these, dimethoxymethylsilane, diethoxymethylsilane, trimethoxysilane and triethoxysilane are preferred.

[0090] The silicon hydride group (-SiH) of the silane compound is added (hydrosilylated) to an unmodified vinyl aromatic copolymer having a carbon-carbon unsaturated bond in the presence of a catalyst containing a Group 8 transition metal, a quinone compound having two or more organic groups with a carbon number of three or more, and a phenolic compound having at least one functional group selected from the group consisting of an ester group, an ether group, a thioether group, an amide group, a urea group, and a carbamate group, thereby obtaining a modified vinyl aromatic copolymer represented by the formula (8) to the formula (13) having a structural unit (c) derived from the silane compound.

[0091] In formula (2) to formula (13), -R 2 -Si-R 3 R 4 R 5 Or -Si-R 7 R 8 R 9 It is called a silane functional group (c) or a structural unit (c). The polymer is a copolymer chain, and the tertiary carbon group and the secondary carbon group between the polymer and the silane functional group (c) are groups generated from the end, side chain and / or center of the copolymer chain. Furthermore, the benzene ring between the silane functional group (c) and the copolymer chain is included in the unit generated by the copolymer chain, and is therefore also a part of the copolymer chain, and the benzene ring may also be other aromatic rings.

[0092] The average number of structural units (c) per molecule is 1 to 20, preferably 1 to 15, more preferably 1 to 10, and even more preferably 1 to 9. When the number is less than 1, when the rubber composition is prepared, the affinity with the filler (C) is low, and the filler dispersibility in the rubber composition cannot be improved. For example, there is a situation where physical properties such as wear resistance and handling stability are not improved, or there is a situation where anti-dry skid performance and anti-wet skid performance are impaired. On the other hand, when it exceeds 20, even the cross-linked product obtained from the rubber composition tends to deteriorate in physical properties such as wear resistance and anti-wet skid performance.

[0093] Its detailed mechanism is not clear, but by introducing an appropriate amount of functional groups into the modified vinyl aromatic copolymer, the modified conjugated diene copolymer (hereinafter also referred to as diene copolymer) becomes easy to concentrate near the reinforcing filler, and the reinforcing effect of the reinforcing filler becomes larger, and it is speculated that the wear resistance of the crosslinked product obtained will be improved. In addition, by passing through the modified vinyl aromatic copolymer, the affinity of the diene copolymer and the reinforcing filler is improved, and it is speculated that the dispersion state of each component such as the reinforcing filler in the rubber composition is ideal for the physical property improvement (for example, the improvement of wear resistance, the improvement of handling stability, anti-dry skid performance, anti-wet skid performance) of the crosslinked product that can be obtained. On the other hand, when the functional group number of the modified vinyl aromatic copolymer is too large, the modified vinyl aromatic copolymer in the diene copolymer is too strongly adsorbed on the reinforcing filler, and therefore, the dispersibility of the reinforcing filler is reduced, and it is speculated that there is no contribution to the improvement of the characteristics (wear resistance, strength) of the crosslinked product containing the diene copolymer and the reinforcing filler.

[0094] On the other hand, when the number of functional groups in the modified copolymer is too large, the copolymer adsorbed to the reinforcing filler is adsorbed too strongly, thereby reducing the dispersibility of the reinforcing filler. It is estimated that the modified vinyl aromatic copolymer does not contribute to the improvement of the properties (wear resistance, strength) of the cross-linked product containing the diene copolymer and the reinforcing filler.

[0095] The average number of functional groups per molecule of the copolymer of the present invention can be calculated by the following formula.

[0096] (Average number of functional groups per molecule) = [(number average degree of polymerization) * (average molecular weight of a repeating unit)] / (equivalent weight of functional groups)

[0097] Furthermore, the equivalent weight of the functional group refers to the mass of the divinyl aromatic compound unit and the monovinyl aromatic compound bonded to each functional group. The equivalent weight of the functional group can be calculated using 1 H-NMR (Nuclear Magnetic Resonance, NMR) or 13 C-NMR, and calculated from the area ratio of the peak derived from the functional group to the peak derived from the polymer main chain. In addition, the peak derived from the functional group refers to the peak derived from the alkoxy group.

[0098] In the method for producing a modified vinyl aromatic copolymer of the present invention, the amount of the silane compound represented by the formula (15) and / or the formula (16) used is preferably 1 to 200 parts by mass, more preferably 1 to 100 parts by mass, further preferably 1 to 60 parts by mass, further preferably 1 to 50 parts by mass, and further preferably 1 to 40 parts by mass, based on 100 parts by mass of the multifunctional vinyl aromatic copolymer.

[0099] When the amount used is more than 200 parts by mass, the dispersibility of the reinforcing filler is poor, the processability is deteriorated, and the wear resistance of the obtained cross-linked product tends to be reduced. When the amount used is less than 1 part by mass, the dispersibility of the reinforcing filler is poor, and the dispersion state of the reinforcing filler etc. tends not to be ideal for improving the physical properties of the obtained cross-linked product.

[0100] The amount of the silane compound added to the modified vinyl aromatic copolymer can be determined using various analytical instruments such as nuclear magnetic resonance spectroscopy.

[0101] The method for adding the silane compound represented by the formula (15) to the multifunctional vinyl aromatic copolymer is not particularly limited, and for example, the silane compound can be added to the multifunctional vinyl aromatic copolymer, and a free radical catalyst can be added as needed, and the mixture can be heated in the presence or absence of an organic solvent. The free radical generator used is not particularly limited, and commercially available organic peroxides, azo compounds, hydrogen peroxide, etc. can be used.

[0102] Examples of the organic peroxide include methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 1,1-bis(tert-hexylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, hydroperoxide), 2,5-dimethylhexane 2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, dicumyl peroxide, bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-hexanoyl peroxide, lauroyl peroxide, peroxysuccinic acid, benzoyl peroxide and its substitutes, 2,4-dichlorobenzoyl Peroxide, m-toluoyl peroxide, diisopropyl peroxydicarbonate, tert-butyl 2-ethylhexanoate, di-2-ethylhexyl peroxydicarbonate, dimethoxyisopropyl peroxycarbonate, di(3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peracetate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert-butyl peroxyoctanoate, tert-butyl peroxy 3,3,5-trimethylhexanoate, tert-butyl peroxylaurate, tert-butyl peroxycarbonate, tert-butyl peroxybenzoate, tert-butyl peroxyisobutyrate, etc.

[0103] Examples of the azo compounds include 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), 2,2'-azobis(2-(2-imidazolin-2-yl)propane), 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(2-methylpropane), 2,2'-azobis(2-hydroxymethylpropionitrile), 4,4'-azobis(4-cyanovaleric acid), dimethyl 2,2'-azobis(2-methylpropionate), 2-cyano-2-propylazocarbonamide, and 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile.

[0104] As the organic solvent used in the method, hydrocarbon solvents and halogenated hydrocarbon solvents can be generally listed. Among these organic solvents, hydrocarbon solvents such as n-butane, n-hexane, n-heptane, cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, decane, benzene, toluene and xylene are preferred.

[0105] Furthermore, when the reaction of the addition-modified compound is carried out by the above method, an anti-aging agent may be added from the viewpoint of suppressing side reactions.

[0106] Preferred antioxidants used in this case include, for example, 2,6-di-tert-butyl-4-methylphenol (2,6-dit-butyl-4-methylphenol, BHT), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 4,4'-butylenebis(3-methyl-6-tert-butylphenol) (AO-40), 3,9-bis[1,1-dimethyl-2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (AO-80). , 2,4-bis[(octylthio)methyl]-6-methylphenol (Irganox 1520L), 2,4-bis[(dodecylthio)methyl]-6-methylphenol (Irganox 1726), 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate (Sumilizer GS), 2-tert-butyl-6-(3-tert-butyl-2-hydroxy -5-methylbenzyl)-4-methylphenyl acrylate (Sumilizer GM), 6-tert-butyl-4-[3-(2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphinane-6-yloxy)propyl]-2-methylphenol (Sumilizer GP), tris(2,4-di-tert-butylphenyl)phosphite (Irgafos 168), dioctadecyl 3,3'-dithiodipropionate, hydroquinone, p-methoxyphenol, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (Nocrac 6C), bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (LA-77Y), N,N-dioctadecylhydroxylamine (Irgastab FS042), bis(4-tert-octylphenyl)amine (Irganox 5057), etc. The anti-aging agent may be used alone or in combination of two or more.

[0107] The amount of the antioxidant added is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, relative to 100 parts by mass of the unmodified multifunctional vinyl aromatic copolymer.

[0108] It is undesirable to carry out the reaction of adding silane-based compounds to multifunctional vinyl aromatic copolymers only by heating without using free radical generators. For example, when the heating temperature is too low, addition reaction can not be fully caused, and the average number of functional groups of each molecule is not within the desired range sometimes. In addition, when the heating temperature is increased, addition reaction may be carried out sometimes, but due to the generation of free radicals on the polymer main chain, the multi-quantization reaction of polymers may also be carried out simultaneously sometimes, so when the Mw of the modified vinyl aromatic copolymer cannot reach the desired range, the viscosity of the copolymer may not reach the desired range sometimes. In these cases where the temperature during addition reaction is high, when the handling property of the copolymer deteriorates due to high viscosity, the physical property of the tire rubber composition obtained may be adversely affected due to the reduction of the reactivity with silica sometimes. On the other hand, when using free radical generators to carry out addition reaction, even at relatively low temperatures, side reactions such as multi-quantization reaction may be fully suppressed, and the addition reaction may be fully carried out simultaneously.

[0109] When the maximum peak molecular weight in terms of polystyrene obtained by GPC measurement of the modified vinyl aromatic copolymer is set to Mt, and the total area of ​​the GPC chromatogram derived from the copolymer obtained by GPC measurement is set to 100%, the proportion of the polymer in the region where the molecular weight is Mt×1.45 or more is preferably in the range of 0% to 40%, more preferably in the range of 0% to 30%, further preferably in the range of 0% to 20%, and particularly preferably in the range of 0% to 10%.

[0110] In the modified vinyl aromatic copolymer of the present invention, the position for introducing the functional group may be the polymerization end or the side chain of the polymer chain, but from the viewpoint of being able to easily introduce multiple functional groups, the side chain of the polymer chain is preferred. In addition, the functional group may contain one alone or two or more. Therefore, the copolymer may be modified by one modifying compound or by two or more modifying compounds.

[0111] The mixing ratio of the unmodified multifunctional vinyl aromatic copolymer and the silane compound represented by the formula (15) can be appropriately set so that, for example, the average number of functional groups per molecule of the copolymer becomes a desired value. For example, the mass ratio of the unmodified multifunctional vinyl aromatic copolymer to the silane compound (former / latter) can be mixed in the range of 0.3 to 100, and can also be mixed in the range of 0.3 to 50.

[0112] As a method for producing the copolymer of the present invention, it is effective to react the silane compound represented by the formula (15) with a free radical addition reaction at an appropriate reaction temperature and for a sufficient reaction time. For example, the temperature in the reaction of adding the silane compound to the multifunctional vinyl aromatic copolymer is preferably 10°C to 200°C, more preferably 50°C to 180°C, and further preferably 50°C to 140°C. In addition, the reaction time is preferably 1 to 200 hours, more preferably 1 to 100 hours, further preferably 1 to 50 hours, and further preferably 1 to 25 hours.

[0113] In addition, the method for adding the silane compound represented by the formula (16) to the multifunctional vinyl aromatic copolymer is not particularly limited. For example, the following method can be adopted: in the presence of a catalyst containing a Group 8 transition metal, a quinone compound having two or more organic groups with a carbon number of three or more, and a phenolic compound having at least one functional group selected from the group consisting of an ester group, an ether group, a thioether group, an amide group, a urea group, and a carbamate group in the multifunctional vinyl aromatic copolymer, the silane compound is added (hydrosilylated) to an unmodified vinyl aromatic copolymer having an unsaturated group.

[0114] The silane compound represented by formula (16) plays a role of introducing reactive silicon groups into the unmodified vinyl aromatic copolymer by addition reaction (hydroquinoneation) with the unmodified vinyl aromatic copolymer having a carbon-carbon unsaturated bond.

[0115] The amount of the silane compound represented by the formula (16) used is important in terms of its ratio (molar ratio) to the unsaturated groups in the polyfunctional vinyl aromatic copolymer. The molar ratio (the number of moles of the silane compound represented by the formula (16) / the number of moles of the unsaturated groups) is preferably 0.1 to 20, and more preferably 0.5 to 3.

[0116] The polyfunctional vinyl aromatic copolymer is a polyfunctional vinyl aromatic copolymer having at least one unsaturated group in the molecule that can undergo addition reaction (hydrosilylation reaction) with a hydrosilyl group. In addition, the unsaturated group is sometimes referred to as an unsaturated group with hydrosilylation activity. The number of unsaturated groups with hydrosilylation activity present in one molecule of the polyfunctional vinyl aromatic copolymer is 1 to 20, preferably 1 to 15, more preferably 1 to 10, and particularly preferably 1 to 9.

[0117] The catalyst used when adding (hydrosilylation) the silane compound represented by the formula (16) to the polyfunctional vinyl aromatic copolymer having a carbon-carbon unsaturated bond contains a Group 8 transition metal. Examples of the Group 8 transition metal include cobalt, nickel, ruthenium, rhodium, palladium, iridium, and platinum.

[0118] As catalysts containing Group 8 transition metals, examples include metal elements, metal salts or complexes of Group 8 transition metals with organic compounds, such as: chloroplatinic acid supported by platinum on a carrier such as alumina, silica, carbon black, etc.; chloroplatinic acid complexes containing chloroplatinic acid and alcohols, aldehydes, ketones, etc.; platinum-olefin complexes [such as Pt(CH2=CH2)2(PPh3), Pt(CH2=CH2)2Cl2]; platinum-vinylsiloxane complexes [Pt{(vinyl(vinyl))Me2SiOSiMe2(vinyl)}, Pt{Me(vinyl)SiO}4]; platinum-phosphine complexes [Ph(PPh3)4, Pt(PBu3)4]; platinum-phosphite complexes [Pt{P(OPh)3}4], etc.

[0119] Also preferred are dichlorodicarbonylplatinum, platinum-hydrocarbon complexes described in US Pat. Nos. 3,159,601 and 3,159,662 of Ashby, and platinum-alkoxide catalysts described in US Pat. No. 3,220,972 of Lamoreaux.

[0120] In addition, a platinum chloride-olefin complex described in US Pat. No. 3,516,946 of Modic is also preferred.

[0121] Among the catalysts containing a Group 8 transition metal, chloroplatinic acid, a platinum-olefin complex, a platinum-acetylacetone complex, and a platinum-vinylsiloxane complex are more preferred because of their high reactivity.

[0122] The catalyst may be added to the reaction system alone or in combination of two or more.

[0123] The ratio of the amount of the catalyst added to the amount of the unmodified vinyl aromatic copolymer having carbon-carbon unsaturated bonds is important, and as a molar ratio (the number of moles of the catalyst / the number of moles of the unsaturated groups), it is preferably 10:1. -1 ~10 -8 , more preferably 10 -3 ~10 -6 When the molar ratio (moles of catalyst / moles of unsaturated groups) is less than 10 -8 In the case of a molar ratio of more than 10, the hydrosilylation reaction may not proceed sufficiently. -1 In the case of such a situation, problems such as increased raw material costs, product coloration and reduced transparency due to the inclusion of catalyst residues may occur.

[0124] As a method for adding the catalyst, a method of dissolving the catalyst in various solvents and adding the catalyst is preferred in order to stabilize the catalyst, facilitate handling, etc. The solvent used when dissolving the catalyst in a solvent and adding the catalyst is not particularly limited, and examples thereof include hydrocarbon solvents such as benzene, toluene, and xylene; halogenated hydrocarbons; alcohols; glycols; ethers; esters, etc.

[0125] The quinone compound is used together with the catalyst and plays the role of a co-catalyst of the catalyst.

[0126] The quinone compound is not particularly limited, and examples thereof include 2,5-di-tert-butyl-1,4-benzoquinone, 2,6-di-tert-butyl-1,4-benzoquinone, 1,4-benzoquinone, 2-methyl-1,4-benzoquinone, 2,6-dimethyl-1,4-benzoquinone, 2,3,5,6-tetramethyl-1,4-benzoquinone, 2-tert-butyl-1,4-benzoquinone, 1,4-naphthoquinone, and 2-methyl-1,4-naphthoquinone (vitamin K3). Among these, 2,5-di-tert-butyl-1,4-benzoquinone and 2,6-di-tert-butyl-1,4-benzoquinone are preferred from the viewpoints of reactivity, coloration suppression, and toxicity.

[0127] As a method for adding the quinone compound to the reaction system, the quinone compound can be added directly, but from the viewpoints of easy handling and uniform dispersion in the entire reaction solution, it is preferred to dissolve the quinone compound in a solvent to form a uniform diluted solution before adding. In addition, the addition method can be any method of all at once, batchwise, or continuously.

[0128] The solvent used when the quinone compound is diluted in a solvent and added is not particularly limited, and examples thereof include hydrocarbon solvents such as benzene, toluene, xylene, and hexane, or halogenated hydrocarbons, alcohols, glycols, ethers, and esters.

[0129] Furthermore, as disclosed by Jean Fisher et al. (Chem. Eur. J., 4, 2008-2017, (1998)), when a quinone compound (D) is added in an amount equimolar to that of the catalyst, the amount of the quinone compound added relative to the catalyst is small, and sometimes the effect of the present invention cannot be fully achieved.

[0130] In addition, the ratio of the added amount of the quinone compound to the added amount of the unmodified vinyl aromatic copolymer having a carbon-carbon unsaturated bond is also important. As a molar ratio (the number of moles of the quinone compound / the number of moles of the unsaturated group), it is preferably 0.00001 to 100 times, more preferably 0.0001 to 10 times, and particularly preferably 0.001 to 1 times.

[0131] In the production method of the present invention, a phenolic compound having at least one functional group selected from the group consisting of an ester group, an ether group, a thioether group, an amide group, a urea group, and a carbamate group in its structure may be used.

[0132] The phenolic compound is used together with the catalyst and is considered to play a role as a cocatalyst of the catalyst. By adding the phenolic compound, the hydrosilylation reaction can be carried out at a better reaction rate than the existing system using the catalyst and the quinone compound alone under the condition of adding a small amount of oxygen. Furthermore, the generation of side reaction products is suppressed, and the amount of the catalyst and the quinone compound added can be reduced.

[0133] The phenolic compound is not particularly limited as long as it has at least one functional group selected from the group consisting of an ester group, an ether group, a thioether group, an amide group, a urea group, and a carbamate group in its structure, and preferably has an alkyl group having 1 to 20 carbon atoms as a functional group at the 2-position or 6-position relative to the phenolic hydroxyl group in its structure. Examples of such compounds include phenolic compounds containing an ester group such as ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], pentaerythritoltetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, isooctyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate; and phenolic compounds containing a sulfur group such as thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. Phenolic compounds containing an ether group; phenolic compounds containing an amide group such as N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide]; phenolic compounds containing an ether group such as 3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol, among which preferred are ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], pentaerythritoltetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and isooctyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0134] The phenolic compounds may be used alone or as a mixture of two or three.

[0135] As a method for adding the phenolic compound to the reaction system, the phenolic compound can be added directly, but from the viewpoint of being uniformly dispersed in the entire reaction solution, it is preferred to heat and melt the phenolic compound and add it as a liquid, or to dissolve the phenolic compound in a solvent to form a uniform dilute solution and then add it. In addition, as a method of adding, any method of all at once, batchwise, or continuously can be used.

[0136] The solvent used when the phenol compound is diluted in a solvent and added is not particularly limited, and examples thereof include hydrocarbon solvents such as benzene, toluene, xylene, and hexane, or halogenated hydrocarbons, alcohols, glycols, ethers, and esters.

[0137] The ratio of the amount of the phenolic compound added to the amount of the organic polymer having an unsaturated group added is also important, and the molar ratio (number of moles of the phenolic compound / number of moles of the unsaturated group) is preferably 0.0002 to 1 times, more preferably 0.001 to 0.5 times, and particularly preferably 0.005 to 0.1 times.

[0138] The hydrosilylation reaction can be carried out in the absence of a solvent or in the presence of a solvent. The solvent used in the hydrosilylation reaction is not particularly limited, and examples thereof include hydrocarbons, halogenated hydrocarbons, ethers, esters, etc. Among these, heptane, hexane, benzene, toluene, xylene, etc. are preferred.

[0139] The hydrosilylation reaction is carried out under an inert gas such as nitrogen or helium to ensure safety in handling combustible materials. However, from the viewpoint of promoting the hydrosilylation reaction, it is preferred to mix oxygen in the inert gas within a range that does not give an explosive mixed composition.

[0140] The volume fraction of oxygen contained in the gas phase in the reaction vessel is preferably 0.1% or more, more preferably 0.5% to 10%. When the volume fraction of oxygen is less than 0.1%, the promoting effect of the hydrosilylation reaction is sometimes not shown. The reaction temperature of the hydrosilylation reaction is preferably 30°C to 200°C, more preferably 50°C to 150°C. The reaction time is not particularly limited, but is preferably 30 minutes to 15 hours, more preferably 30 minutes to 10 hours, and most preferably 30 minutes to 6 hours.

[0141] The modified vinyl aromatic copolymer of the present invention contains 0.5 mol % to 95.0 mol % of a structural unit derived from a divinyl aromatic compound.

[0142] When the structural unit contains only the structural unit (a) and the structural unit (b), the molar fraction of the structural unit (a) is 0.005 to 0.95 relative to the total of the structural unit (a) and the structural unit (b). The molar fraction is calculated by the following formula (7).

[0143] (a) / [(a)+(b)]…(7)

[0144] (Here, (a): the molar fraction of the structural unit (a) derived from the divinyl aromatic compound, and (b): the molar fraction of the structural unit (b) derived from the monovinyl aromatic compound.)

[0145] The preferred lower limit of the molar fraction is 0.006, more preferably 0.007. The preferred upper limit is 0.80, more preferably 0.70. The most suitable range is 0.01 to 0.60.

[0146] Furthermore, when the structural units other than the structural units (a) and the structural units (b) are included, the preferred lower limit of the content is 0.2 mol%, more preferably 0.4 mol%, and further preferably 0.6 mol%. In addition, the preferred upper limit is 70 mol%, more preferably 60 mol%, and further preferably 50 mol%.

[0147] The modified vinyl aromatic copolymer of the present invention contains 5.0 mol% to 99.5 mol% of the structural unit (b) derived from the monovinyl aromatic compound. In terms of molar fraction, it is 0.05 to 0.995. The preferred lower limit is 0.20. The more preferred lower limit is 0.30. In addition, the preferred upper limit is 0.994, and more preferably 0.993. The most suitable is 0.40 to 0.99.

[0148] When only the structural unit (a) and the structural unit (b) are included, the molar fraction of the structural unit (b) is calculated by the following formula (8).

[0149] (b) / [(a)+(b)](8)

[0150] In addition, when the structural unit (a) and a structural unit other than the structural unit (b) are contained, the preferred molar fraction of the structural unit (b) is also within the above range.

[0151] The structural unit (a) derived from the divinyl aromatic compound contains a vinyl group as a branch component for expressing copolymerization reactivity with the conjugated diene compound, while the structural unit (b) derived from the monovinyl aromatic compound does not have a vinyl group that participates in the curing reaction and thus imparts moldability, compatibility, etc.

[0152] If the molar fraction of the structural unit (a) is less than 0.005, the heat resistance of the cured product is insufficient, and if it exceeds 0.95, the formability is reduced. If the molar fraction of the structural unit (b) is more than 0.995, the heat resistance is reduced, and if it is less than 0.05, the formability is reduced.

[0153] The copolymer of the present invention may contain other structural units in addition to the above structural units. The details of other structural units can be understood from the description of the production method.

[0154] The Mn (number average molecular weight in terms of standard polystyrene measured by gel permeation chromatography) of the copolymer of the present invention is 500 to 100,000, preferably 600 to 50,000, and more preferably 700 to 40,000. It is further preferably 800 to 30,000, and most preferably 900 to 20,000. The most suitable is 900 to 10,000. If Mn is less than 300, the amount of monofunctional copolymer contained in the copolymer increases, so there is a tendency for the copolymerization reactivity with the conjugated diene compound to decrease. In addition, if Mn exceeds 100,000, gel is easily generated, and there is a tendency for the molding processability or tensile elongation at break to decrease. The molecular weight distribution is 30.0 or less, preferably 25.0 or less, and more preferably 1.3 to 20.0. The most suitable is 2.0 to 15.0. If Mw / Mn exceeds 30.0, the processing characteristics of the copolymer rubber tend to deteriorate and gel tends to be generated.

[0155] The copolymer of the present invention can be dissolved in a solvent selected from toluene, xylene, tetrahydrofuran, dichloroethane or chloroform, but is advantageously soluble in any of the above solvents. Since it is a multifunctional copolymer soluble in a solvent, a part of the vinyl groups of divinylbenzene must not be cross-linked and must have an appropriate degree of branching. The copolymer or its production method is known from the above patent documents, etc. Moreover, the copolymer can be soluble in 50 g or more of the solvent in 100 g. More preferably, 80 g or more of the copolymer can be soluble.

[0156] Next, a method for producing an unmodified multifunctional vinyl aromatic copolymer (also referred to as an unmodified copolymer) as a precursor of the modified vinyl aromatic copolymer of the present invention will be described. The copolymer of the present invention can be advantageously produced by the above production method.

[0157] In the method for producing the unmodified copolymer, polymerization is carried out at a temperature of 0°C to 120°C in a uniform solvent prepared by dissolving a polymerization raw material containing a divinyl aromatic compound and a monovinyl aromatic compound in a solvent having a dielectric constant of 2.0 to 15.0 in the presence of a Lewis acid catalyst.

[0158] Divinyl aromatic compounds make copolymer branches and form multifunctional, and play an important role as a cross-linking component for making copolymers generate branches when copolymerized with conjugated diene compounds. As the example of divinyl aromatic compounds, divinylbenzene (including each isomer), divinylnaphthalene (including each isomer), divinylbiphenyl (including each isomer) are preferably used, but are not limited to these. In addition, these can be used alone or in combination of two or more. From the viewpoint of forming processability, divinylbenzene (inter-body, isomer or isomer mixture of these) is more preferably used.

[0159] Monovinyl aromatic compounds improve the solvent solubility, compatibility, and processability of copolymers. Examples of monovinyl aromatic compounds include vinyl aromatic compounds such as styrene, vinyl naphthalene, vinyl biphenyl, and α-methyl styrene; nuclear alkyl-substituted vinyl aromatic compounds such as o-methyl styrene, m-methyl styrene, p-methyl styrene, o-, p-dimethyl styrene, o-ethyl vinyl benzene, m-ethyl vinyl benzene, and p-ethyl vinyl benzene; cyclic vinyl aromatic compounds such as indene, acenaphthene, benzothiophene, and coumarone, but are not limited thereto. In order to prevent the gelation of the copolymer and improve the solubility, compatibility, and processability in the solvent, styrene, ethyl vinyl benzene (including each isomer), ethyl vinyl biphenyl (including each isomer), ethyl vinyl naphthalene (including each isomer) and indene are particularly preferably used from the perspective of cost and ease of acquisition. From the perspective of compatibility and cost, styrene, ethyl vinyl benzene (inter-body, para-body, or a mixture of isomers thereof), and indene are more preferred.

[0160] In addition, in the production method, in addition to the divinyl aromatic compound and the monovinyl aromatic compound, other monomers such as a trivinyl aromatic compound, a trivinyl aliphatic compound or a divinyl aliphatic compound, a monovinyl aliphatic compound, a cycloolefin compound, etc. can also be used within the range that does not impair the effects of the present invention, and the structural unit (e) derived from these other monomers can be introduced into the copolymer.

[0161] As specific examples of the other monomers, preferably 1,3,5-trivinylbenzene, 1,3,5-trivinylnaphthalene, 1,2,4-trivinylcyclohexane, ethylene glycol diacrylate, butadiene, isobutylene, diisobutylene, 2-methyl-1-butene, 2-methyl-1-pentene, 1-methyl-1-cyclopentene, 2-methyl-1-hexene, 1-methyl-1-cyclohexene, 2-methyl-1-heptene, 2-methyl-1-octene, 2-methyl-1-decene, 2-methyl-1-dodecene, 2-methyl-1-tetradecene, 2-methyl-1-hexadecene, 2-methyl-1-octadecene, 2-methyl-1-eicosene, 2-methyl-1-ticosene, 2-methyl-1-ticosene, etc. can be listed, but they are not limited to these. These can be used alone or in combination of two or more. Other monomers can be used in the range of less than 30 mol% of all monomers. Thereby, the content of the structural unit (e) derived from other monomers is within the range of less than 30 mol % based on the total amount of the structural units in the copolymer.

[0162] In the method for producing an unmodified copolymer, a copolymer is produced by polymerizing a monomer containing a divinyl aromatic compound and a monovinyl aromatic compound, and optionally other monomers, in the presence of a Lewis acid catalyst.

[0163] The usage ratio of each component as a monomer can be set as the following range with respect to 100 mol% of the total of the divinyl aromatic compound and the monovinyl aromatic compound.

[0164] Divinyl aromatic compound: 0.5 mol% to 95 mol%, preferably 0.3 mol% to 65 mol%, more preferably 0.4 mol% to 55 mol%, most preferably 5 mol% to 50 mol%.

[0165] Monovinyl aromatic compound: 7 mol% to 99 mol%, preferably 10 mol% to 95 mol%, more preferably 15 mol% to 90 mol%.

[0166] As the Lewis acid catalyst used here, as long as it is a compound comprising a metal ion (acid) and a ligand (base) and can receive an electron pair, it can be used without particular limitation. Among the Lewis acid catalysts, from the viewpoint of the heat decomposition resistance of the obtained copolymer, preferably a metal fluoride or its complex, particularly preferably a divalent to hexavalent metal fluoride or its complex of B, Al, Ga, In, Si, Ge, Sn, Pb, Sb, Bi, Ti, W, Zn, Fe and V. These catalysts can be used alone or in combination of two or more. From the viewpoint of the control of the molecular weight and molecular weight distribution of the obtained copolymer and the polymerization activity, it is most preferably to use an ether complex of boron trifluoride. Here, as the ether of the ether complex, there are diethyl ether, dimethyl ether, etc.

[0167] Regarding the Lewis acid catalyst, relative to the total of 100 moles of all monomer components, the Lewis acid catalyst can be used in the range of 0.001 mole to 100 moles, more preferably 0.01 mole to 50 moles. Most preferably, it is 0.1 mole to 10 moles. If it exceeds 100 moles, the polymerization rate becomes too large, so it is difficult to control the molecular weight distribution. In addition, if it is less than 0.001 mole, the polymerization rate becomes too small, thus resulting in an increase in cost, which is not suitable for industrial implementation.

[0168] In the production method, one or more Lewis basic compounds may be used as co-catalysts as desired.

[0169] Specific examples of the Lewis basic compound include the following compounds.

[0170] 1) Ester compounds such as ethyl acetate, butyl acetate, phenyl acetate, methyl propionate, etc.

[0171] 2) Thioester compounds such as methyl mercaptopropionate and ethyl mercaptopropionate;

[0172] 3) Ketone compounds such as methyl ethyl ketone, methyl isobutyl ketone, and benzophenone;

[0173] 4) Amine compounds such as methylamine, ethylamine, propylamine, butylamine, cyclohexylamine, methylethylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine;

[0174] 5) Ether compounds such as diethyl ether and tetrahydrofuran;

[0175] 6) Sulfide compounds such as diethyl sulfide and diphenyl sulfide; and

[0176] 7) Phosphine compounds such as tripropylphosphine, tributylphosphine, trihexylphosphine, tricyclohexylphosphine, trioctylphosphine, vinylphosphine, allylphosphine, cyclohexenylphosphine, dienylphosphine and trialenylphosphine.

[0177] Among these, ester compounds and ketone compounds are preferably used because they act synergistically with a Lewis acid catalyst and can easily control the polymerization rate and the molecular weight distribution of the polymer.

[0178] These Lewis basic compounds may be used alone or in combination of two or more.

[0179] The Lewis basic compound as a cocatalyst component controls the interaction between the carbon cation as an active species and the counter anion by coordinating with the Lewis acid catalyst as a counter anion during the polymerization reaction, thereby adjusting the relative reaction frequency between the growth reaction and the chain transfer reaction, thereby contributing to the quantity control. Generally, by adding the Lewis basic compound, the interaction between the carbon cation as an active species and the counter anion is enhanced, thereby suppressing the excessive insertion reaction of the divinyl aromatic compound and the monovinyl aromatic compound, facilitating the chain transfer reaction after the insertion reaction of the monomer, suppressing the excessive increase of the molecular weight, and thus making it easy to control the molecular weight.

[0180] The Lewis basic compound as a cocatalyst is preferably 0.005 mol to 500 mol, more preferably 0.01 mol to 200 mol, and further preferably 0.1 mol to 100 mol relative to 100 mol of the total of all monomers. If it is within the above range, the polymerization rate is appropriately maintained, and at the same time, the selectivity of the reaction between the monomers is improved, and a copolymer with excellent productivity, suppressed excessive increase or decrease in molecular weight, and excellent molding processability can be obtained.

[0181] The polymerization reaction is carried out by dissolving a polymerization raw material including the above-mentioned monomer mixture and a Lewis acid catalyst in a uniform solvent having a dielectric constant of 2.0 to 15.0, and performing cationic copolymerization at a temperature of 20°C to 120°C.

[0182] The solvent is a compound that does not substantially hinder cationic polymerization, and can be an organic solvent that dissolves the catalyst, polymerization additive, cocatalyst, monomer, and the generated vinyl aromatic copolymer to form a uniform solution, and has a dielectric constant in the range of 2.0 to 15.0, and can be used alone or in combination of two or more. If the dielectric constant of the solvent is less than 2.0, the molecular weight distribution becomes broad, which is not preferred, and if the dielectric constant of the solvent exceeds 15.0, the polymerization rate decreases.

[0183] As an organic solvent, toluene, xylene, n-hexane, cyclohexane, methylcyclohexane or ethylcyclohexane are particularly preferred from the viewpoint of the balance between polymerization activity and solubility. In addition, in consideration of the viscosity of the obtained polymerization solution or the ease of heat removal, the amount of the solvent is determined in such a way that the concentration of the copolymer in the polymerization solution becomes 1wt% to 90wt%, preferably 10wt% to 80wt%, and particularly preferably 20wt% to 70wt% at the end of the polymerization. When the concentration is less than 1wt%, the cost increases due to the low polymerization efficiency. If the concentration exceeds 90wt%, the molecular weight and molecular weight distribution increase, resulting in a decrease in molding processability.

[0184] When producing an unmodified copolymer, polymerization needs to be performed at a temperature of 20° C. to 120° C., preferably 40° C. to 100° C. If the polymerization temperature exceeds 120° C., the selectivity of the reaction decreases, thereby causing problems such as an increase in molecular weight distribution or the generation of gels. If the polymerization is performed at a temperature below 20° C., the catalyst activity decreases significantly, so a large amount of catalyst needs to be added.

[0185] The method for recovering the copolymer after the polymerization reaction is terminated is not particularly limited, and a commonly used method such as a heating concentration method, a steam stripping method, and precipitation in a poor solvent may be used.

[0186] The unmodified copolymer obtained by the production method contains a structural unit (a) derived from a divinyl aromatic compound and a structural unit (b) derived from a monovinyl aromatic compound, and at least a part of the structural unit (a) derived from the divinyl aromatic compound is present in the form of a vinyl-containing structural unit (a1) represented by the formula (1). Furthermore, the copolymer is soluble in toluene, xylene, tetrahydrofuran, dichloroethane or chloroform.

[0187] The copolymer of the present invention synthesized from the unmodified copolymer can be formed and cured alone because it has a reactive silane functional group, but other polymerizable resins can be used for modification and synthesis of high molecular weight multi-branched components. In particular, the modified vinyl aromatic copolymer of the present invention is used for modification and synthesis of high molecular weight multi-branched components when obtaining a conjugated diene copolymer (rubber) obtained by copolymerizing a conjugated diene compound alone and / or a conjugated diene compound with other monomers.

[0188] Next, a modified vinyl aromatic copolymer having two or more terminal groups modified with a modifying group having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group is described. (Second Form)

[0189] The modified vinyl aromatic copolymer of the present invention (hereinafter also referred to as modified copolymer or copolymer A') is a copolymer containing a structural unit (a) derived from a divinyl aromatic compound and a structural unit (b) derived from a monovinyl aromatic compound, wherein 95 mol% or more of the structural unit (a) is a crosslinked structural unit (a1) represented by the formula (1), and at least two of its terminals are modified with a modifying group having the functional group.

[0190] The divinyl aromatic compound unit (a) contained in the modified vinyl aromatic copolymer plays an important role as a cross-linking component that branches the copolymer and forms a multifunctional cross-linking component. When the multifunctional modified vinyl aromatic copolymer is used to modify the polymer of the conjugated diene compound, a high molecular weight multi-branch component is generated, which can improve the wear resistance.

[0191] As examples of divinyl aromatic compounds, divinylbenzene (including each isomer), divinylnaphthalene (including each isomer), and divinylbiphenyl (including each isomer) are preferably used, but are not limited to these. In addition, these can be used alone or in combination of two or more. From the viewpoint of molding processability, divinylbenzene (inter-isomer, para-isomer, or isomer mixture of these) is more preferred.

[0192] On the other hand, monovinyl aromatic compounds improve the solvent solubility, compatibility and processability of copolymers. As examples of monovinyl aromatic compounds, vinyl aromatic compounds such as styrene, vinyl naphthalene, vinyl biphenyl, α-methyl styrene, etc. can be cited; core alkyl substituted vinyl aromatic compounds such as o-methyl styrene, m-methyl styrene, p-methyl styrene, o-, p-dimethyl styrene, o-ethyl vinyl benzene, m-ethyl vinyl benzene, p-ethyl vinyl benzene, etc.; cyclic vinyl aromatic compounds such as indene, acenaphthene, benzothiophene, benzofuran, etc., but are not limited to these. In order to prevent the gelation of the copolymer, improve the solubility, compatibility and processability in the solvent, from the perspective of cost and ease of acquisition, styrene, ethyl vinyl benzene (including each isomer), ethyl vinyl biphenyl (including each isomer), ethyl vinyl naphthalene (including each isomer) and indene are particularly preferably used. From the perspective of compatibility and cost, styrene, ethyl vinyl benzene (inter-body, para-body or a mixture of isomers of these), indene are more preferred.

[0193] The modified copolymer can be produced by the production method of the present invention.

[0194] The manufacturing method of the present invention comprises: a polymerization step, using an alkali metal compound or an alkaline earth metal compound as an anionic polymerization initiator to copolymerize a divinyl aromatic compound and a monovinyl aromatic compound, or a divinyl aromatic compound and a monovinyl aromatic compound with a monomer capable of anionic copolymerization with these compounds, to obtain a vinyl aromatic copolymer having a branched structure and an active terminal; and a terminal modification step, forming the functional group at the active terminal of the vinyl aromatic copolymer.

[0195] Here, the monomer capable of anionic copolymerization improves the toughness and compatibility of the copolymer. As the monomer capable of anionic copolymerization, butadiene, isoprene, 2,3-dimethylbutadiene, 2-phenylbutadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, laurylene, and conjugated dienes (b1) other than butadiene and isoprene such as chloroprene. As the monomer capable of anionic copolymerization contained in the modified vinyl aromatic copolymer of the present invention, butadiene and isoprene are preferably used from the perspective of ease of industrial implementation.

[0196] The vinyl aromatic copolymer having the branched structure and active ends is a multi-branched vinyl aromatic copolymer with unmodified active ends, and is also a precursor of the modified copolymer of the present invention. In the method for producing the vinyl aromatic copolymer having the branched structure and active ends, in addition to the divinyl aromatic compound and the monovinyl aromatic compound, other monomers such as trivinyl aromatic compounds may be used within the range not impairing the effects of the present invention, and the structural unit (e) derived from these other monomers may be introduced into the copolymer.

[0197] As specific examples of the other monomers, preferably 1,3,5-trivinylbenzene, 1,3,5-trivinylnaphthalene, etc. can be cited, but are not limited thereto. These can be used alone or in combination of two or more. Other monomers can be used in the range of less than 30 mol% of all monomers. Thus, the structural unit (e) derived from other monomers is in the range of less than 30 mol% relative to the total amount of the structural units in the copolymer.

[0198] In the method for producing the unmodified multifunctional vinyl aromatic copolymer, the copolymer is produced by polymerizing a monomer comprising a divinyl aromatic compound and a monovinyl aromatic compound, or optionally other monomers, in the presence of a polymerization initiator comprising an alkali metal compound or an alkaline earth metal compound.

[0199] At least a part of the structural unit (a) becomes the crosslinked structural unit (a1) represented by the formula (1), which means that the molar fraction (also called the degree of crosslinking) of the crosslinked structural unit (a1) derived from the divinyl aromatic compound relative to the structural unit (a) is 0.95 or more.

[0200] The crosslinking degree of the crosslinking structural unit (a1) is in the range of 0.95 or more, and the preferred lower limit is 0.98 or more, and more preferably 0.99 or more.

[0201] The cross-linking degree is a parameter that can be arbitrarily controlled and changed. However, if the cross-linking degree is less than 0.95, since many highly reactive side vinyl groups remain in the modified copolymer of the present invention, when the polymer is used in the modification of a conjugated diene (co)polymer, due to the thermal history in subsequent steps, an intramolecular cross-linking reaction starting from the side vinyl groups remaining in the copolymer is likely to occur, resulting in a tendency to generate microgels during compounding and vulcanization.

[0202] As described above, the method for producing the modified copolymer includes a polymerization step and a terminal modification step.

[0203] The polymerization initiator composed of an alkali metal compound or an alkaline earth metal compound used in the polymerization step will be described.

[0204] There is no particular limitation on the alkali metal compound used as a polymerization initiator, and for example, an organic lithium compound is preferably used. As an organic lithium compound, it can be any one of a low molecular weight organic lithium compound and a solubilized oligomer organic lithium compound. Among the bonding modes of the organic group and lithium, compounds having a carbon-lithium bond, compounds having a nitrogen-lithium bond, compounds having a tin-lithium bond, etc. can be listed. If an organic lithium compound is used, the initiation efficiency is good and the activity rate of the polymer is also good. As an organic lithium compound, there is no particular limitation, and for example, organic monolithium compounds, organic dilithium compounds, and organic polylithium compounds can be listed. As an organic group, a hydrocarbon containing a functional group is preferably used, which has the advantage of excellent solubility in an organic solvent and an excellent initiation rate. In addition, by using a compound having a nitrogen-lithium bond or a compound having a tin-lithium bond, a modified group containing a functional group can also be given to the initiation end.

[0205] There are no particular restrictions on other organic alkali metal compounds other than the organic lithium compound, and examples thereof include organic sodium compounds, organic potassium compounds, organic rubidium compounds, and organic cesium compounds. More specifically, sodium naphthalene and potassium naphthalene may be mentioned. In addition, alkoxides, sulfonates, carbonates, and amides of lithium, sodium, and potassium may also be mentioned. In addition, it may be used in combination with other organic metal compounds.

[0206] As alkaline earth metal compounds, organic magnesium compounds, organic calcium compounds, and organic strontium compounds can be cited. In addition, compounds such as alkoxides, sulfonates, carbonates, and amides of alkaline earth metals can also be used. These organic alkaline earth metal compounds can also be used in combination with the alkali metal compounds and other organic metal compounds.

[0207] There are no particular limitations on the alkali metal compound with a functional group that can be used as a polymerization initiator, and examples include lithium amide compounds obtained by lithiation of hydrogen of a secondary amine, and alkyl lithiums bonded to the functional group. Thus, a functional group can be imparted to the polymerization initiation end of the conjugated diene copolymer. There are no particular limitations on the functional group, and preferably a functional group that is inert to the alkali metal, such as a disubstituted amino group, i.e., a tertiary amine, a protected monosubstituted amino group, and a protected amino group. Furthermore, as a protected monosubstituted amino group or a protected amino group, for example, one hydrogen of a monosubstituted amino group or two hydrogens of an amino group are substituted with a trimethylsilyl group.

[0208] The organolithium compound is not particularly limited, and examples thereof include: monoorganic lithium compounds such as n-butyl lithium, sec-butyl lithium, tert-butyl lithium, n-propyl lithium, isopropyl lithium, and benzyl lithium; and polyfunctional organolithium compounds such as 1,4-dilithium butane, 1,5-dilithium pentane, 1,6-dilithium hexane, 1,10-dilithium decane, 1,1-dilithium diphenylene, dilithium polybutadiene, dilithium polyisoprene, 1,4-dilithium benzene, 1,2-dilithium-1,2-diphenylethane, 1,4-dilithium-2-ethylcyclohexane, 1,3,5-trilithium benzene, and 1,3,5-trilithium-2,4,6-triethylbenzene. Among these, monoorganic lithium compounds such as n-butyl lithium, sec-butyl lithium, and tert-butyl lithium are preferred.

[0209] The polymerization initiator having a functional group is not particularly limited, and specific examples thereof include the compounds shown below. In addition, the types of functional groups that can be imparted to the polymer are described in parentheses.

[0210] For example, there are dipropyl amide lithium, diisopropyl amide lithium, dibutyl amide lithium, tetramethylene amide lithium, pentamethylene amide lithium, hexamethylene amide lithium, heptamethylene amide lithium, 2-dimethylaminoethyl lithium, 3-dimethylaminopropyl lithium, 3-diethylaminopropyl lithium, 4-dimethylaminobutyl lithium (the above are disubstituted amino groups), 2-trimethylsilylethylaminoethyl lithium, 3-trimethylsilylmethylaminopropyl lithium (the above are monosubstituted amino groups), 2-bistrimethylsilylaminoethyl lithium, and 3-bistrimethylsilylaminopropyl lithium (the above are amino groups).

[0211] In addition, as a polymerization initiator, an oligomer initiator obtained by reacting various lithium-based initiators with monomers can be used. At this time, the monomer can use a monomer having at least one functional group selected from the group consisting of amino, alkoxysilyl, and hydroxyl. As an oligomer initiator, there is no particular limitation, and a molecular weight of 1000 or less is easy to industrialize, so it is preferred. Using a polymerization initiator with a functional group for polymerization or copolymerization, a compound having at least one functional group selected from the group consisting of amino, alkoxysilyl, and hydroxyl can be introduced into the active end of the vinyl aromatic copolymer in the next step, or a compound having at least one functional group selected from the group consisting of amino, alkoxysilyl, and hydroxyl can be formed.

[0212] The multifunctional initiator is not particularly limited, and specifically includes organic dilithium compounds and organic polylithium compounds. The organic group is not particularly limited, but is preferably a hydrocarbon. Thus, it has the advantage of excellent solubility in organic solvents and excellent initiation speed.

[0213] The method for preparing the polyfunctional initiator is not particularly limited, and an example thereof includes a method of reacting a dispersion of metallic lithium with a polyhalogenated hydrocarbon compound.

[0214] In the polymerization step, a polar compound may be added to participate in the initiation reaction and the growth reaction, thereby controlling the molecular weight and molecular weight distribution and promoting the polymerization reaction.

[0215] Examples of polar compounds include ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis(2-tetrahydrofuranyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidylethane, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alkoxide compounds such as potassium tert-amylate, potassium tert-butoxide, sodium tert-butoxide, and sodium amylate; phosphine compounds such as triphenylphosphine, etc. These polar compounds may be used alone or in combination of two or more.

[0216] The amount of polar compound used is not particularly limited and can be selected according to the purpose, etc. Usually, it is preferably 0.01 mol to 100 mol relative to 1 mol of polymerization initiator or multifunctional initiator. Such polar compounds can be used in appropriate amounts according to the desired molecular weight and molecular weight distribution as regulators of the initiation reaction and growth reaction of the copolymer. Many polar compounds have an effective randomizing effect in the copolymerization of divinyl aromatic compounds and monovinyl aromatic compounds, and can be used as a regulator of the distribution of aromatic vinyl compounds or a regulator of the amount of styrene blocks.

[0217] The copolymerization of the monomers containing the divinyl aromatic compound and the monovinyl aromatic compound is preferably carried out by solution polymerization in an inert solvent. The polymerization solvent is not particularly limited, and for example, hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons can be used. Specifically, hydrocarbon solvents containing aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, and decalin; aromatic hydrocarbons such as benzene, toluene, and xylene, and mixtures thereof can be cited.

[0218] It is preferred to treat the monomer and the polymerization solvent separately or in a mixed solution thereof with an organic metal compound in advance. In this way, monomers such as divinyl aromatic compounds and monovinyl aromatic compounds, or propadienes or acetylenes contained in the polymerization solvent can be treated. As a result, a polymer having a high concentration of active terminals can be obtained, and a high modification rate can be achieved.

[0219] The polymerization temperature during copolymerization is not particularly limited as long as it is a temperature at which living anionic polymerization can be carried out, but is preferably 0°C or higher from the viewpoint of productivity, and is preferably 120°C or lower from the viewpoint of ensuring a sufficient amount of reactive active terminals in the terminal modification step after the completion of the polymerization, and is more preferably 50°C to 100°C.

[0220] The polymerization reaction method is not particularly limited, and can be carried out in an intermittent (also referred to as "batch"), continuous or other polymerization methods. In the continuous method, one or more connected reactors can be used. The reactor uses a tank type, a tube type or other reactor with a stirrer. In the intermittent method, the molecular weight distribution of the obtained polymer is generally narrow, and it is easy to be more than 1.0 and less than 1.8 in Mw / Mn. In addition, in the continuous method, the molecular weight distribution is generally wide, and it is easy to be more than 1.8 and less than 3 in Mw / Mn.

[0221] [Terminal modification step]

[0222] In the manufacturing method of the present invention, after obtaining a vinyl aromatic copolymer having a branched structure and active ends (also referred to as an unmodified copolymer) in a polymerization step, the active ends are reacted with a compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group, or a compound that forms at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group, thereby implementing a terminal modification step of introducing the functional group.

[0223] The reaction temperature, reaction time, etc. when reacting the compound (including the precursor) having the functional group with the active terminal are not particularly limited, but the reaction is preferably carried out at 0° C. to 120° C. for 30 seconds or more.

[0224] The amount of the compound having the functional group added is not particularly limited, but the total molar number of the compound having the functional group is preferably in the range of 0.01 to 6 times, more preferably in the range of 0.02 to 3 times, and further preferably in the range of 0.05 to 2 times, relative to the molar number of the polymerization initiator or the multifunctional initiator, i.e., the number of polymer molecules. If the amount added is 0.05 times or more, it is preferred from the viewpoint of obtaining a sufficient modification rate in the target modified vinyl aromatic copolymer.

[0225] In this case, the amount of the compound having the functional group added is preferably 0.7 times or less based on the number of moles of the polymerization initiator or polyfunctional initiator, that is, the number of polymer molecules, in terms of functional group equivalent.

[0226] In the case where the polymerization step is intermittent, the terminal modification step can continue the modification reaction in the reactor used in the polymerization step, or it can be transferred to the next reactor. In the case where the polymerization step is continuous, it is transferred to the next reactor. The terminal modification step is preferably carried out immediately after the polymerization step, and preferably the modifying agent is mixed and reacted within 5 minutes. The reactor used for the modification reaction is preferably fully stirred. Specifically, there are static mixer type reactors, tank type reactors with stirrers, etc.

[0227] The terminal modification step is a step of reacting a compound having at least one functional group selected from amino, alkoxysilyl, and hydroxyl groups (including its precursor, which are also referred to as modified compounds) with the active end of the unmodified copolymer to form a bond, or reacting these modified compounds with the active end of the unmodified copolymer to modify the terminal end. Among the modified compounds used in the above step, the functional group bonded to the active end of the conjugated diene polymer is not particularly limited, and specifically includes: halogen group, double bond, ketone group, ester group, amide group, epoxy group, alkoxysilyl group, etc.

[0228] The compound having an amino group in the modified compound is not particularly limited, and specifically, a compound having an amino group and a functional group bonded to the active terminal of the polymer in the molecule, preferably a compound having no active hydrogen, can be cited. The amino group is not particularly limited, and specifically, a functional group that is inert to alkali metals is preferred, and preferably a disubstituted amino group, i.e., a tertiary amine, a protected monosubstituted amino group, and an amino group having two hydrogens protected. Furthermore, examples of protected monosubstituted amino groups or amino groups having two hydrogens protected include those in which one hydrogen of a monosubstituted amino group or two hydrogens of an amino group are substituted with a trimethylsilyl group, respectively.

[0229] The compound having an alkoxysilyl group is not particularly limited, and specifically includes compounds having multiple alkoxysilyl groups in the molecule (including compounds having a silyl group to which multiple alkoxy groups are bonded), and compounds having an alkoxysilyl group and a functional group bonded to an active terminal of a polymer in the molecule. These are preferably compounds having no active hydrogen.

[0230] The compound forming a hydroxyl group is not particularly limited, and specifically, there can be mentioned compounds having a functional group that bonds to the active terminal of the polymer and generates a hydroxyl group after a bonding reaction, and compounds having a functional group that does not bond to the active terminal of the polymer and generates a hydroxyl group by a subsequent reaction such as hydrolysis, but preferably a compound having no active hydrogen.

[0231] Examples of the compound having a functional group that generates a hydroxyl group after the above-mentioned bonding reaction include compounds having a keto group, an ester group, an amide group, an epoxy group, etc. In addition, examples of the compound having a functional group that generates a hydroxyl group by a reaction such as hydrolysis after the bonding reaction include compounds having an alkoxysilyl group, an aminosilyl group, etc.

[0232] Specific examples of the modified compound are shown below: The compound that bonds to the active terminal of the unmodified copolymer to form an amino group at the terminal of the polymer is not particularly limited, and examples thereof include C═N double bond compounds such as N,N′-dicyclohexylcarbodiimide.

[0233] The compound that forms an amino group and a hydroxyl group at the end of the copolymer is not particularly limited, but examples thereof include: ketone compounds having an amino group such as N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone) and N,N,N',N'-tetraethyl-4,4'-diaminobenzophenone; cyclic urea compounds such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone; cyclic amides, i.e., lactam compounds; amino group-containing epoxy compounds such as N,N,N',N'-tetraglycidyl-1,3-bisaminomethylcyclohexane; and epoxy compounds having a nitrogen-containing heterocyclic group described in JP2001-131227A.

[0234] The compound forming the alkoxysilane group at the end of the copolymer is not particularly limited, and examples thereof include halogenated alkoxysilane compounds such as trimethoxychlorosilane, triethoxychlorosilane, and diphenoxydichlorosilane; and polyfunctional alkoxysilane compounds such as bis(trimethoxysilyl)ethane and bis(3-triethoxysilylpropyl)ethane.

[0235] The compound forming an alkoxysilyl group and a hydroxyl group at the terminal of the copolymer is not particularly limited, and examples thereof include 3-glycidyloxypropyltrimethoxysilane and a silanol compound having a 3-glycidyloxypropyltriethoxysilane epoxy group and an alkoxysilyl group in the molecule.

[0236] The compound forming the amino group and the alkoxysilyl group at the end of the copolymer is not particularly limited, and examples thereof include alkoxysilane compounds to which an alkyl group having an amino group as a substituent is bonded, such as 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropyldimethoxymethylsilane, 3-dimethylaminopropyltriethoxysilane, bis(3-trimethoxysilylpropyl)methylamine, and bis(3-triethoxysilylpropyl)methylamine; N-〔3-(triethoxysilyl)-propyl〕- Alkoxysilane compounds having a protected monosubstituted amino group bonded thereto as described in WO2007 / 034785, such as N,N'-diethyl-N'-trimethylsilyl-ethane-1,2-diamine and 3-(4-trimethylsilyl-1-piperazinyl)propyltriethoxysilane; N-〔2-(trimethoxysilyl)-ethyl〕-N,N',N'-trimethylethane-1,2-diamine, 1-〔3-(triethoxysilyl)-propyl〕-4-methylpiperazine, 2-( Alkoxysilane compounds bonded with multiple substituted amino groups as described in WO2008 / 013090A, such as 1,3-dimethylimidazolidine (trimethoxysilyl)-1,3-dimethylimidazolidine and bis-(3-dimethylaminopropyl)-dimethoxysilane; alkoxysilane compounds bonded with nitrogen-containing heterocycles as described in WO2011 / 040312A, such as 1,4-bis-[3-(trimethoxysilyl)propyl]piperazine and 1,4-bis-[3-(triethoxysilyl)propyl]piperazine; 3-[N,N Alkoxysilane compounds to which azasilyl groups are bonded as described in WO2011 / 129425A, such as [bis(trimethylsilyl)amino]propyltrimethoxysilane, 3-[N,N-bis(trimethylsilyl)amino]propylmethyldiethoxysilane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, and 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane.

[0237] The compound that forms a hydroxyl group at the terminal of the copolymer is not particularly limited, and examples thereof include epoxy compounds such as ethylene oxide and propylene oxide; and ketone compounds such as benzophenone.

[0238] The modified copolymer of the present invention or the modified vinyl aromatic copolymer of the present invention obtained by the manufacturing method has a reactive functional group, so it can be formed and hardened alone, but other polymerizable resins can also be used for the synthesis of modified functional groups and high molecular weight multi-branched components. In particular, the modified copolymer is used for the synthesis of modified functional groups and high molecular weight multi-branched components when a conjugated diene compound is obtained alone and / or a conjugated diene copolymer (also called modified rubber) is obtained by copolymerizing a conjugated diene compound with other monomers.

[0239] The modified copolymer of the present invention is excellent as a modifier for conjugated diene (co)polymers (rubbers). The detailed mechanism is not clear, but by introducing an appropriate amount of functional groups into the modified copolymer of the present invention, the rubber is modified to become a modified conjugated diene copolymer (modified rubber), and it is easy to concentrate near the reinforcing filler, the reinforcing effect of the reinforcing filler becomes larger, and it is speculated that the wear resistance of the obtained crosslinked product is improved.

[0240] In addition, the modified copolymer of the present invention has improved affinity with the reinforcing filler through the modified rubber, and it is estimated that the dispersion state of each component such as the reinforcing filler in the rubber composition is ideal for improving the physical properties of the cross-linked product that can be obtained (for example, improvement in wear resistance, improvement in handling stability, dry skid resistance, wet skid resistance).

[0241] On the other hand, when the number of functional groups in the modified rubber becomes too large, the interaction between the modified rubber adsorbed on the reinforcing filler becomes too strong, so the effect of dispersing the reinforcing filler becomes smaller, and it is estimated that the effect of the modified copolymer of the present invention in contributing to improving the affinity between the modified rubber and the reinforcing filler decreases.

[0242] The average number of functional groups per molecule of the modified vinyl aromatic copolymer is preferably in the range of 2 to 20.

[0243] Relative to 100 parts by mass of unmodified multifunctional vinyl aromatic copolymer, the addition amount of the modified compound in the modified vinyl aromatic copolymer is preferably 1 part by mass to 200 parts by mass, more preferably 1 part by mass to 100 parts by mass, further preferably 1 part by mass to 60 parts by mass, further preferably 1 part by mass to 50 parts by mass, and also 1 part by mass to 40 parts by mass. When the amount of the modified compound is more than 200 parts by mass, the dispersibility effect of the reinforcing filler is poor, the processability deteriorates, and the wear resistance of the obtained cross-linked product also tends to decrease. When it is less than 1 part by mass, the dispersibility effect of the reinforcing filler is poor, and the dispersion state of the reinforcing filler, etc., has an undesirable tendency for improving the physical properties of the cross-linked product. Furthermore, the addition amount of the modified compound having a functional group selected from amino, alkoxysilane, and hydroxyl added to the modified vinyl aromatic copolymer can be obtained using various analytical instruments such as nuclear magnetic resonance spectroscopy.

[0244] The modified vinyl aromatic copolymer of the present invention contains 0.5 mol % to 95.0 mol % of the structural unit (a) derived from a divinyl aromatic compound.

[0245] When the structural unit contains only the structural unit (a) and the structural unit (b), the molar fraction of the structural unit (a) is 0.005 to 0.95 relative to the total of the structural unit (a) and the structural unit (b). The molar fraction is calculated by the following formula (7).

[0246] (a) / [(a)+(b)]…(7)

[0247] (Here, (a): the molar fraction of the structural unit (a) derived from the divinyl aromatic compound, and (b): the molar fraction of the structural unit (b) derived from the monovinyl aromatic compound.)

[0248] The preferred lower limit of the molar fraction is 0.006, more preferably 0.007. The preferred upper limit is 0.80, more preferably 0.70. The most suitable range is 0.01 to 0.60.

[0249] Furthermore, when the structural units other than the structural units (a) and the structural units (b) are included, the preferred lower limit of the content is 0.2 mol%, more preferably 0.4 mol%, and further preferably 0.6 mol%. In addition, the preferred upper limit is 70 mol%, more preferably 60 mol%, and further preferably 50 mol%.

[0250] The modified vinyl aromatic copolymer of the present invention contains 5.0 mol% to 99.5 mol% of the structural unit (b) derived from the monovinyl aromatic compound. In terms of molar fraction, it is 0.05 to 0.995. The preferred lower limit is 0.20. The more preferred lower limit is 0.30. In addition, the preferred upper limit is 0.994, and more preferably 0.993. The most suitable is 0.40 to 0.99.

[0251] When only the structural unit (a) and the structural unit (b) are included, the molar fraction of the structural unit (b) is calculated by the following formula (8).

[0252] (b) / [(a)+(b)](8)

[0253] (Here, (a), and (b) have the same meaning as in formula (7))

[0254] In addition, when the structural unit (a) and a structural unit other than the structural unit (b) are contained, the preferred molar fraction of the structural unit (b) is also within the above range.

[0255] The structural unit (a) derived from the divinyl aromatic compound contains a vinyl group as a branch component for expressing copolymerization reactivity with the conjugated diene compound, while the structural unit (b) derived from the monovinyl aromatic compound does not have a vinyl group that participates in the curing reaction and thus imparts moldability, compatibility, etc.

[0256] Furthermore, if the molar fraction of the structural unit (a) is less than 0.005, the heat resistance of the cured product is insufficient, and if it exceeds 0.95, the formability is reduced. In addition, if the molar fraction of the structural unit (b) exceeds 0.995, the heat resistance is reduced, and if it is less than 0.05, the formability is reduced.

[0257] The modified vinyl aromatic copolymer of the present invention may contain not only the above-mentioned structural units but also other structural units. The details of other structural units can be understood from the description of the production method.

[0258] The Mn (number average molecular weight in terms of standard polystyrene measured by gel permeation chromatography) of the modified vinyl aromatic copolymer of the present invention is 500 to 100,000, preferably 600 to 50,000, and more preferably 700 to 40,000. It is further preferably 800 to 30,000, and most preferably 900 to 20,000. The most suitable is 900 to 10,000. If Mn is less than 300, the amount of functional groups contained in the copolymer is reduced, so there is a tendency for the reactivity with the active end of the conjugated diene copolymer to decrease. In addition, if Mn exceeds 100,000, it is not only easy to generate gel, but also there is a tendency for the molding processability or tensile elongation at break to decrease. The molecular weight distribution is 30.0 or less, preferably 25.0 or less, and more preferably 1.3 to 20.0. The most suitable is 1.6 to 15.0. If Mw / Mn exceeds 30.0, not only will the processing properties of the copolymer rubber tend to deteriorate, but also gel will tend to be generated.

[0259] The modified vinyl aromatic copolymer of the present invention can be dissolved in a solvent selected from toluene, xylene, tetrahydrofuran, ethylene dichloride or chloroform, but advantageously can be dissolved in any of the solvents. Since it is a multifunctional copolymer that can be dissolved in a solvent, it is necessary that a part of the vinyl groups of divinylbenzene is not crosslinked and remains due to functional group modification, and has a moderate degree of branching. The copolymer or its preparation method is known by the patent literature, etc. Moreover, it can be a copolymer that dissolves more than 50g in 100g of solvent. More preferably, it dissolves more than 80g.

[0260] The modified vinyl aromatic copolymer of the present invention obtained by the manufacturing method has at least one reactive functional group selected from amino, alkoxysilyl, and hydroxyl groups, so it can be formed and cured alone, but other polymerizable resins can also be used for the synthesis of modified functional groups and high molecular weight multi-branched components. In particular, the modified vinyl aromatic copolymer of the present invention is used for the synthesis of modified functional groups and high molecular weight multi-branched components when a conjugated diene compound is obtained alone and / or a conjugated diene copolymer (rubber) obtained by copolymerizing a conjugated diene compound with other monomers.

[0261] Next, the conjugated diene copolymer of the present invention will be described.

[0262] The modified conjugated diene copolymer is obtained by reacting the modified vinyl aromatic copolymer (A) or (A') of the present invention as a modifier with a polymer of a conjugated diene compound (B) having an active terminal, or a copolymer of a conjugated diene compound (B) having an active terminal and an aromatic vinyl compound (C). Hereinafter, the polymer of the conjugated diene compound (B) or the copolymer of a conjugated diene compound (B) having an active terminal and an aromatic vinyl compound (C) are also collectively referred to as diene polymers.

[0263] The first embodiment of the modified vinyl aromatic copolymer (A) and the second embodiment of the modified vinyl aromatic copolymer (A′) can be used in the same manner, and therefore both of them will also be referred to as the modified vinyl aromatic copolymer (A) hereinafter.

[0264] By copolymerizing the modified vinyl aromatic copolymer (A) of the present invention as a raw material with 1) a conjugated diene compound (B), or 2) a conjugated diene compound (B) and an aromatic vinyl compound (C), a modified conjugated diene copolymer having a branched polymer-type modifying group based on the modified vinyl aromatic copolymer of the present invention can be obtained. When the aromatic vinyl compound (C) is not used, a modified diene rubber such as butadiene rubber or isoprene rubber can be obtained, and by using the aromatic vinyl compound (C), a modified conjugated diene copolymer such as SBR can be obtained. These modified conjugated diene copolymers show the characteristics of rubber and are therefore also called modified copolymer rubbers.

[0265] The polymerization steps for obtaining the modified conjugated diene copolymer of the present invention include: a polymerization step, using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator to polymerize a conjugated diene compound (B), or copolymerize a conjugated diene compound (B) and an aromatic vinyl compound (C) to obtain a conjugated diene copolymer with an active terminal; and a terminal modification step, introducing a branched polymer-type modifying group based on the modified vinyl aromatic copolymer.

[0266] Examples of the conjugated diene compound (B) include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene, and 1,3-hexadiene. Among these, 1,3-butadiene and isoprene are preferred. These may be used alone or in combination of two or more.

[0267] As the aromatic vinyl compound (C), styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, vinylxylene, 4-cyclohexylstyrene, 2,4,6-trimethylstyrene, tert-butoxydimethylsilylstyrene and isopropoxydimethylsilylstyrene can be used alone or in combination of two or more thereof. Among these, styrene is particularly preferred.

[0268] When 1,3-butadiene is used as the conjugated diene compound (B) and styrene is used as the aromatic vinyl compound, so-called styrene-butadiene rubber (SBR) is obtained. In addition, when styrene is not used as the aromatic vinyl compound, when 1,3-butadiene is used as the conjugated diene compound (B), so-called butadiene rubber (BR) is obtained. When isoprene is used as the conjugated diene compound (B) and there is no structural unit of the aromatic vinyl compound (C), it becomes isoprene rubber (IR). Among them, if it has a styrene-butadiene rubber (SBR) structure, it is particularly preferred because of its excellent wear resistance, heat resistance, and aging resistance.

[0269] [Polymerization step using a polymerization initiator]

[0270] There is no particular restriction on the alkali metal compound used as a polymerization initiator, and for example, an organic lithium compound is preferably used. As an organic lithium compound, it can be any one of a low molecular weight organic lithium compound and a solubilized oligomer organic lithium compound. Among the bonding modes of the organic group and lithium, compounds with carbon-lithium bonds, compounds with nitrogen-lithium bonds, compounds with tin-lithium bonds, etc. can be listed. If an organic lithium compound is used, the initiation efficiency is good and the activity rate of the polymer is also good. As an organic lithium compound, there is no particular restriction, and for example, organic monolithium compounds, organic dilithium compounds, and organic polylithium compounds can be listed. As an organic group, a hydrocarbon containing a functional group is preferably used, which has the advantage of excellent solubility in an organic solvent in the case described, and the initiation speed is also excellent. In addition, by using a compound having a nitrogen-lithium bond or a compound having a tin-lithium bond, a modified group containing a functional group can also be given to the initiation end.

[0271] As other organic alkali metal compounds other than the organic lithium compound, there is no particular limitation, and examples thereof include organic sodium compounds, organic potassium compounds, organic rubidium compounds, and organic cesium compounds. More specifically, sodium naphthalene and potassium naphthalene may be mentioned. In addition, alkoxides, sulfonates, carbonates, and amides of lithium, sodium, and potassium may also be mentioned. In addition, it may be used in combination with other organic metal compounds.

[0272] As the alkaline earth metal compound used as the polymerization initiator, organic magnesium compounds, organic calcium compounds, organic strontium compounds, etc. can be listed. In addition, compounds such as alkoxides, sulfonates, carbonates, and amides of alkaline earth metals can also be used. These organic alkaline earth metal compounds can be used in combination with the alkali metal compounds and other organic metal compounds.

[0273] There are no particular limitations on the alkali metal compound with a functional group that can be used as a polymerization initiator, and examples include lithium amide compounds obtained by lithiation of hydrogen of a secondary amine, and alkyl lithiums bonded to the functional group. Thus, a functional group can be imparted to the polymerization initiation end of the conjugated diene copolymer. There are no particular limitations on the functional group, and preferably a functional group that is inert to the alkali metal, such as a disubstituted amino group, i.e., a tertiary amine, a protected monosubstituted amino group, and a protected amino group. Furthermore, as a protected monosubstituted amino group or a protected amino group, for example, one hydrogen of a monosubstituted amino group or two hydrogens of an amino group are substituted with a trimethylsilyl group.

[0274] The organolithium compound used as the initiator is not particularly limited, and examples thereof include: monoorganolithium compounds such as n-butyllithium, sec-butyllithium, tert-butyllithium, n-propyllithium, isopropyllithium, and benzyllithium; and polyfunctional organolithium compounds such as 1,4-dilithium butane, 1,5-dilithium pentane, 1,6-dilithium hexane, 1,10-dilithium decane, 1,1-dilithium diphenylene, dilithium polybutadiene, dilithium polyisoprene, 1,4-dilithium benzene, 1,2-dilithium-1,2-diphenylethane, 1,4-dilithium-2-ethylcyclohexane, 1,3,5-trilithium benzene, and 1,3,5-trilithium-2,4,6-triethylbenzene. Among these, monoorganolithium compounds such as n-butyllithium, sec-butyllithium, and tert-butyllithium are preferred.

[0275] As the polymerization initiator with functional group, it is not particularly limited, and specifically the compounds shown below can be enumerated. Furthermore, the kind of functional group that can be given to polymer is recorded in brackets. For example, there are dipropyl lithium amide, diisopropyl lithium amide, dibutyl lithium amide, tetramethylene lithium amide, pentamethylene lithium amide, hexamethylene lithium amide, heptamethylene lithium amide, 2-dimethylamino ethyl lithium, 3-dimethylamino propyl lithium, 3-diethylamino propyl lithium, 4-dimethylamino butyl lithium (above disubstituted amino), 2-trimethylsilylethylamino ethyl lithium, 3-trimethylsilylmethylamino propyl lithium (above monosubstituted amino), 2-bis-trimethylsilylamino ethyl lithium, 3-bis-trimethylsilylamino propyl lithium (above amino).

[0276] In addition, as a polymerization initiator, an oligomer initiator formed by the reaction of various lithium-based initiators and monomers can be used. In this case, the monomer can use a monomer having at least one functional group selected from the group consisting of amino, alkoxysilyl, and hydroxyl. As an oligomer initiator, there is no particular limitation, and a molecular weight of 1000 or less is easy to industrialize, so it is preferred. Using a polymerization initiator with a functional group for polymerization or copolymerization, in the next step, a branched polymer-type modifying group derived from the modified vinyl aromatic copolymer of the present invention can be introduced at the terminal.

[0277] Furthermore, the polymerization step when a multifunctional initiator is used is a step of polymerizing a conjugated diene compound (B) or copolymerizing a conjugated diene compound (B) and an aromatic vinyl compound (C) using a multifunctional initiator to obtain a conjugated diene copolymer having an active terminal.

[0278] Thereafter, as a method for introducing functional groups into two or more ends of a conjugated diene copolymer having active ends, a terminal modification step is performed, wherein a modified vinyl aromatic copolymer is reacted with two or more active ends of the conjugated diene copolymer to introduce two or more branched polymer-type modifying groups (A) based on the modified vinyl aromatic copolymer.

[0279] (Multifunctional initiator)

[0280] The multifunctional initiator is not particularly limited, and specifically includes organic dilithium compounds and organic polylithium compounds. The organic group is not particularly limited, but is preferably a hydrocarbon. Thus, it has the advantage of excellent solubility in organic solvents and excellent initiation speed.

[0281] In addition, the preparation method of the multifunctional initiator is not particularly limited, and specifically includes: a method based on the reaction of a dispersion of metallic lithium with a polyhalogenated hydrocarbon compound, a method based on the reaction of metallic lithium with a diene compound, and a method based on the reaction of an organic monolithium compound with a multifunctional compound. Among these, a method based on the reaction of an organic monolithium compound with a multifunctional compound is preferred. As a multifunctional compound, it is not particularly limited, and specifically includes a compound that is an aromatic compound and has multiple double bonds adjacent to an aromatic group, and a compound that has multiple active hydrogens that can be substituted with lithium. When the organic monolithium compound is reacted with these multifunctional compounds, a conjugated diene compound and an aromatic vinyl compound are allowed to exist, and an oligomer can also be prepared. In addition, in order to improve the reactivity of the organic monolithium compound, polar compounds such as ether compounds and tertiary amine compounds may also be present. The compound that is an aromatic compound and has multiple double bonds adjacent to an aromatic group is not particularly limited, for example, diisopropenylbenzene, divinylbenzene, etc. The compound having a plurality of active hydrogen atoms that can be substituted with lithium is not particularly limited, and examples thereof include 1,3,5-trimethylbenzene and the like.

[0282] The hydrocarbon dilithium compound is not particularly limited, and examples thereof include 1,3-bis(1-lithium-1,3-dimethylpentyl)benzene, 1,4-bis(1-lithium-1,3-dimethylpentyl)benzene, 1,3-bis(1-lithium-1,3,3-trimethylbutyl)benzene, and 1,4-bis(1-lithium-1,3,3-trimethylbutyl)benzene obtained by the reaction of secondary or tertiary butyl lithium and diisopropenylbenzene.

[0283] The hydrocarbon polylithium compound is not particularly limited, and examples thereof include a reaction product of n-butyllithium, divinylbenzene, and 1,3-butadiene, and a reaction product of secondary or tertiary butyllithium and 1,3,5-trimethylbenzene.

[0284] The amount of these multifunctional initiators used is adjusted according to the molecular weight of the target butadiene polymer, and 0.01 to 0.2 parts by mass can be used relative to 100 parts by mass of the monomer. Preferably, 0.02 to 0.15 parts by mass are used. At this time, it is preferred to consider the deactivation caused by moisture and impurities in the monomer and the solvent, the chain transfer caused by impurities, the deactivation caused by the generation of metal hydrides at the polymerization terminal, etc.

[0285] When manufacturing a conjugated diene copolymer, a polar compound may be added. By adding a polar compound, a vinyl aromatic compound and a conjugated diene compound such as 1,3-butadiene can be randomly copolymerized. In addition, the polar compound can also be used as a vinylating agent to control the microstructure of the conjugated diene part. In addition, there is also an effect of promoting polymerization reaction.

[0286] Examples of polar compounds include ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis(2-tetrahydrofuranyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidylethane, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alkoxide compounds such as potassium tert-amylate, potassium tert-butoxide, sodium tert-butoxide, and sodium amylate; phosphine compounds such as triphenylphosphine, etc. These polar compounds may be used alone or in combination of two or more.

[0287] The amount of polar compound used is not particularly limited and can be selected according to the purpose, etc. Usually, it is preferably 0.01 to 100 moles relative to 1 mole of polymerization initiator or multifunctional initiator. Such polar compounds can be used in appropriate amounts according to the required vinyl bond amount as a regulator of the microstructure of the conjugated diene part of the polymer. Many polar compounds have an effective randomizing effect in the copolymerization of conjugated diene compounds and aromatic vinyl compounds, and can be used as a regulator of the distribution of aromatic vinyl compounds and the amount of styrene blocks. As a method for randomizing conjugated diene compounds and aromatic vinyl compounds, for example, a method as described in Japanese Patent Laid-Open No. 59-140211 can be used, in which the total amount of styrene and a part of the conjugated diene compound (B) are started to copolymerize, and the remaining conjugated diene compound (B) is added continuously or intermittently in the middle of the copolymerization.

[0288] In the polymerization, the polymerization or copolymerization of the conjugated diene compound (B) is preferably carried out by solution polymerization in an inert solvent. As the polymerization solvent, there is no particular limitation, for example, hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons can be used. Specifically, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, and decane; aromatic hydrocarbons such as benzene, toluene, and xylene, and hydrocarbon solvents of mixtures thereof can be cited.

[0289] Preferably, the conjugated diene compound and the polymerization solvent are treated separately or in a mixed solution thereof using an organometallic compound in advance. Thus, the allenes or acetylenes contained in the conjugated diene compound or the polymerization solvent can be treated. As a result, a polymer having a high concentration of active terminals can be obtained, and a high modification rate can be achieved.

[0290] The polymerization temperature when the conjugated diene compound (B) or the conjugated diene compound (B) and the aromatic vinyl compound (C) are copolymerized is not particularly limited as long as it is a temperature for carrying out living anionic polymerization, but is preferably 0° C. or higher from the viewpoint of productivity, and is preferably 120° C. or lower from the viewpoint of sufficiently ensuring the reaction amount of the modified vinyl aromatic copolymer having the structural unit (c) containing the silane functional group represented by the formula (2) and / or the formula (3) of the present invention relative to the active terminal after the completion of the polymerization. More preferably, it is 50° C. to 100° C.

[0291] The polymerization method for copolymerizing the conjugated diene compound (B) or the conjugated diene compound (B) with the aromatic vinyl compound (C) is not particularly limited, and can be carried out in an intermittent manner (also referred to as "batch mode"), a continuous manner or the like. In the continuous mode, one or more connected reactors can be used. The reactor uses a tank type, a tube type or the like reactor with a stirrer. In the intermittent mode, the molecular weight distribution of the obtained polymer is generally narrow, and it is easy to be more than 1.0 and less than 1.8 in Mw / Mn. In addition, in the continuous mode, the molecular weight distribution is generally wide, and it is easy to be more than 1.8 and less than 3 in Mw / Mn.

[0292] [Terminal modification step]

[0293] The terminal modification step is a step of reacting the modified vinyl aromatic copolymer of the present invention with the active terminal of the conjugated diene copolymer to introduce the functional group and synthesize a multi-branched high molecular weight body. The step is the same when a polymerization initiator is used and when the multifunctional initiator is used.

[0294] There is no particular limitation on the reaction temperature, reaction time, etc. when the modified vinyl aromatic copolymer is reacted with the active end of the polymer, and the reaction is preferably carried out at 0°C to 120°C for more than 30 seconds. The amount of the modified vinyl aromatic copolymer added is not particularly limited, but the total molar number of the modified vinyl aromatic copolymer (A) is preferably in the range of 0.01 to 6 times, more preferably in the range of 0.02 to 3 times, and further preferably in the range of 0.05 to 2 times, relative to the molar number of the polymerization initiator or the multifunctional initiator, that is, the number of polymer molecules. If the amount added is 0.05 times or more, it is preferred from the viewpoint of obtaining a sufficient modification rate in the target modified conjugated diene polymer. In addition, in order to improve processability, the branching degree and the generated amount of the branched polymer component formed by coupling the polymer ends to each other can also be arbitrarily controlled by the structure of the modified vinyl aromatic copolymer (A). In this case, a modified vinyl aromatic copolymer (A) with a high degree of functionality can be used as the modified vinyl aromatic copolymer (A). The amount of the modified vinyl aromatic copolymer (A) added is preferably 0.7 times or less the number of moles of the polymerization initiator or polyfunctional initiator, that is, the number of polymer molecules, in terms of functional group equivalent.

[0295] The terminal modification step can continue the modification reaction in the reactor used in the polymerization step when the polymerization step is intermittent, or can be transferred to the next reactor. When the polymerization step is continuous, it is transferred to the next reactor. The terminal modification step is preferably carried out immediately after the polymerization step, and preferably the modifier is mixed and reacted within 5 minutes. The reactor used for the modification reaction is preferably fully stirred. Specifically, there are static mixer type reactors, tank type reactors with stirrers, etc.

[0296] Furthermore, in order to prevent side reactions of bonding between functional groups of the modified vinyl aromatic copolymer or to improve affinity with different types of fillers, one or more functional groups different from those of the modified vinyl aromatic copolymer may be introduced into the active ends of the conjugated diene copolymer.

[0297] In the case of introducing a functional group different from the modified vinyl aromatic copolymer into the active end of the conjugated diene copolymer, a modified compound having at least one functional group selected from amino, alkoxysilyl, and hydroxyl is reacted with the active end of the conjugated diene copolymer to form a bond, or a compound forming these functional groups is reacted with the active end of the conjugated diene copolymer to modify the terminal end. Among the modified compounds used at this time, the functional group bonded to the active end of the conjugated diene polymer is not particularly limited, and specifically, halogen groups, double bonds, ketone groups, ester groups, amide groups, epoxy groups, alkoxysilyl groups, etc. can be cited.

[0298] (Modified compound)

[0299] The terminal modification step is a step of reacting a modifying compound having at least one functional group selected from an amino group, an alkoxysilyl group, and a hydroxyl group with the active terminal of the butadiene copolymer to form a bond, or reacting a compound forming these functional groups with the active terminal of the butadiene copolymer to modify the terminal terminal. In the modifying compound used in the step, the functional group bonded to the active terminal of the conjugated diene polymer is not particularly limited, and specifically includes a halogen group, a double bond, a ketone group, an ester group, an amide group, an epoxy group, an alkoxysilyl group, and the like.

[0300] The compound having an amino group in the modified compound is not particularly limited, and specifically, a compound having an amino group and a functional group bonded to the active terminal of the polymer in the molecule, preferably a compound having no active hydrogen, can be cited. The amino group is not particularly limited, and specifically, a functional group inert to alkali metals is preferred, and preferably a disubstituted amino group, i.e., a tertiary amine, a protected monosubstituted amino group, and an amino group having two hydrogens protected. Furthermore, examples of protected monosubstituted amino groups or amino groups having two hydrogens protected include those in which one hydrogen of a monosubstituted amino group or two hydrogens of an amino group are substituted with a trimethylsilyl group, respectively.

[0301] The compound having an alkoxysilyl group in the modifier is not particularly limited, and specifically includes compounds having multiple alkoxysilyl groups in the molecule (including compounds having a silyl group to which multiple alkoxy groups are bonded), and compounds having an alkoxysilyl group and a functional group bonded to the active terminal of the polymer in the molecule. These are preferably compounds having no active hydrogen.

[0302] The hydroxyl-forming compound in the modifier is not particularly limited, and specific examples include compounds having a functional group that bonds to the active terminal of the polymer and generates a hydroxyl group after a bonding reaction, and compounds having a functional group that does not bond to the active terminal of the polymer and generates a hydroxyl group by a subsequent reaction such as hydrolysis. Compounds having no active hydrogen are preferred.

[0303] Examples of the compound having a functional group that generates a hydroxyl group after the bonding reaction include compounds having a keto group, an ester group, an amide group, an epoxy group, etc. In addition, examples of the compound having a functional group that generates a hydroxyl group by a reaction such as hydrolysis after the bonding reaction include compounds having an alkoxysilyl group, an aminosilyl group, etc.

[0304] Specific examples of the modified compound are shown below: The compound that bonds to the active terminal of the polymer to form an amino group at the terminal of the polymer is not particularly limited, and examples thereof include C═N double bond compounds such as N,N′-dicyclohexylcarbodiimide.

[0305] The compound that bonds to the active end of the polymer to form an amino group and a hydroxyl group at the end of the polymer is not particularly limited, but examples thereof include: ketone compounds having an amino group such as N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone) and N,N,N',N'-tetraethyl-4,4'-diaminobenzophenone; cyclic urea compounds such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone; cyclic amides, i.e., lactam compounds; amino group-containing epoxy compounds such as N,N,N',N'-tetraglycidyl-1,3-bisaminomethylcyclohexane; and epoxy compounds having a nitrogen-containing heterocyclic group described in Japanese Patent Laid-Open No. 2001-131227.

[0306] The compound that bonds to the active end of the polymer to form an alkoxysilane group at the end of the polymer is not particularly limited, and examples thereof include halogenated alkoxysilane compounds such as trimethoxychlorosilane, triethoxychlorosilane, and diphenoxydichlorosilane; and multifunctional alkoxysilane compounds such as bis(trimethoxysilyl)ethane and bis(3-triethoxysilylpropyl)ethane.

[0307] The compound that bonds to the active terminal of the polymer to form an alkoxysilyl group and a hydroxyl group at the terminal of the polymer is not particularly limited, and examples thereof include 3-glycidyloxypropyltrimethoxysilane and a silanol compound having a 3-glycidyloxypropyltriethoxysilane epoxy group and an alkoxysilyl group in the molecule.

[0308] The compound that bonds to the active end of the polymer to form an amino group and an alkoxysilyl group at the end of the polymer is not particularly limited, and examples thereof include alkoxysilane compounds to which an alkyl group having an amino group as a substituent is bonded, such as 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropyldimethoxymethylsilane, 3-dimethylaminopropyltriethoxysilane, bis(3-trimethoxysilylpropyl)methylamine, and bis(3-triethoxysilylpropyl)methylamine; N-[3-(triethoxysilylpropyl)-1-methyl-1-yl]-2-nitropropane; Alkoxysilane compounds having a protected monosubstituted amino group bonded thereto as described in WO2007 / 034785A, such as N-〔2-(trimethoxysilyl)-ethyl〕-N,N',N'-trimethylethane-1,2-diamine, 1-〔3-(triethoxysilyl)-propyl〕-4-methyl Alkoxysilane compounds bonded with multiple substituted amino groups as described in WO2008 / 013090, such as piperazine, 2-(trimethoxysilyl)-1,3-dimethylimidazolidine, and bis-(3-dimethylaminopropyl)-dimethoxysilane; alkoxysilane compounds bonded with nitrogen-containing heterocycles as described in WO2011 / 040312, such as 1,4-bis[3-(trimethoxysilyl)propyl]piperazine and 1,4-bis[3-(triethoxysilyl)propyl]piperazine; 3-[ Alkoxysilane compounds to which azasilyl groups are bonded as described in WO2011 / 129425, such as N,N-bis(trimethylsilyl)amino]propyltrimethoxysilane, 3-[N,N-bis(trimethylsilyl)amino]propylmethyldiethoxysilane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, and 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane.

[0309] The compound that bonds to the active terminal of the polymer to form a hydroxyl group at the terminal of the polymer is not particularly limited, and examples thereof include epoxy compounds such as ethylene oxide and propylene oxide; and ketone compounds such as benzophenone.

[0310] 〔Main chain modification step〕

[0311] The main chain modification step is a step of modifying the main chain by subjecting the vinyl group of the main chain of the modified conjugated diene polymer with the modified terminal to a hydrosilylation reaction with a silicon compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group, or a silicon compound forming at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, or a hydroxyl group. The step is the same in both the case of using a polymerization initiator and the case of using the multifunctional initiator.

[0312] The hydrosilylation reaction can be carried out directly in an organic solvent solution or in a polymer (in a solvent-free state) in a mixer. Specifically, a silicon compound such as a hydrosilane compound having the functional group can be reacted in the presence of a catalyst to modify the vinyl group of the main chain of the conjugated diene copolymer. After the polymerization step in the solution polymerization, it is preferred to directly use a polymer solution in which the terminal portion of the polymer has been modified as described above.

[0313] The silicon compound is not particularly limited, and specifically, a hydrosilane compound can be cited. Such a hydrosilane compound is not particularly limited, and specifically, any hydrosilane compound can be cited as long as it has at least one functional group selected from the group consisting of an amino group, an alkoxysilane group, and a hydroxyl group. Among them, the general formula HSiR" is preferably cited. 3- n X n , (R" is not particularly limited and represents a hydrocarbon group with 1 to 20 carbon atoms, X represents a hydrocarbon or organic silane compound group having at least one functional group selected from the group consisting of amino, alkoxy, hydroxyl or amino, alkoxysilyl, hydroxyl, and n is 1 to 3) represented by a hydrosilane compound. More preferably, n is 1, and it is also preferred that R" represents a hydrocarbon with 1 to 3 carbon atoms. When the hydrosilane compound has such a structure, the yield of the hydrosilylation reaction is high.

[0314] In addition, the silicon compound may be one that forms the functional group by hydrolysis after hydrosilylation reaction. Such silicon compound is not particularly limited, and specifically, a hydrosilane compound having a functional group that forms at least one of an amino group, an alkoxysilyl group, or a hydroxyl group by hydrolysis, etc. More specifically, a hydrosilane compound having a protected monosubstituted amino group, a protected disubstituted amino group, a protected hydroxyl group, etc. may be mentioned.

[0315] The silicon compound having an alkoxy group is not particularly limited, and specific examples thereof include organic siloxane compounds having an H-Si group and an alkoxysilyl group in the molecule, such as dimethylmonomethoxysilane, dimethylmonoethoxysilane, dimethylmonopropoxysilane, dimethylmonobutoxysilane, methyldimethoxysilane, methyldiethoxysilane, methyldipropoxysilane, ethyldiethoxysilane, trimethoxysilane, and triethoxysilane.

[0316] The silicon compound having a disubstituted amino group is not particularly limited, and specific examples thereof include dimethylaminodimethylsilane, diethylaminodimethylsilane, diethylaminodiethylsilane, 3-diethylaminopropyldimethylsilane, 4-dimethylaminobutyldimethylsilane, and 6-diethylaminohexyldimethylsilane.

[0317] The silicon compound having a protected monosubstituted amino group is not particularly limited, and specific examples thereof include N-methyl-N-trimethylsilylaminodimethylsilane and N-ethyl-N-trimethylsilylaminodiethylsilane.

[0318] The silicon compound having a protected disubstituted amino group is not particularly limited, and specific examples thereof include N,N-bistrimethylsilylaminodimethylsilane and N,N-bistrimethylsilylaminodiethylsilane.

[0319] The silicon compound having a hydroxy group is not particularly limited, and specific examples thereof include dimethylhydroxysilane, diethylhydroxysilane, and dibutylhydroxysilane.

[0320] The silicon compound that forms a hydroxyl group by hydrolysis is not particularly limited, and specific examples thereof include alkoxysilane compounds such as dimethylmonomethoxysilane, dimethylmonoethoxysilane, methyldimethoxysilane, trimethoxysilane, and triethoxysilane; and silane compounds having an epoxy group such as dimethylglycidylsilane and diethylglycidylsilane.

[0321] When the vinyl group of the main chain of the modified conjugated diene copolymer is modified, the amount of the hydrosilane compound to be reacted is arbitrary according to the purpose, and is preferably 1 to 10 moles relative to 1 mole of the main chain of the copolymer. By modifying 1 to 10 moles relative to 1 mole of the main chain, as described later, when the modified diene copolymer is mixed with silica to obtain a rubber composition, good affinity can be obtained, and excellent processability can be obtained. More preferably, it is 2 to 5 moles relative to 1 mole of the main chain.

[0322] When performing the hydrosilation reaction, a prescribed catalyst may also be used. There are no particular restrictions on the catalyst, for example, platinum or platinum-containing catalysts are mainly used. Preferably, a uniform platinum catalyst is suitably used, for example, chloroplatinic acid solution (i.e., Speier catalyst), Pt2(divinyltetramethyldisiloxane)3 solution (i.e., Karstedt catalyst), dichloro(η4-cyclo-1,5-diene)Pt(II), etc. The amount of the platinum catalyst used in the reaction is preferably 0.01 mmol / mol to 10 mmol / mol relative to the hydrosilane compound, and more preferably 0.1 mmol / mol to 1 mmol / mol.

[0323] Examples of the catalyst used in the hydrosilylation reaction include metallocene compounds containing any one of Ti, Zr, Hf, Ni, Co, Ru, and Rh, and a reaction product of a titanocene compound and an organic lithium or organic aluminum is particularly preferred.

[0324] The hydrosilylation reaction is preferably carried out in the range of 20°C to 150°C, more preferably in the range of 50°C to 120°C. Within the above range, it can be carried out within an appropriate reaction time, and there are few side reactions such as gelation, which is practical. Furthermore, when the polymerization solution is directly used and the hydrosilylation reaction is carried out after the terminal modification reaction, it can be carried out at the same temperature as the polymerization temperature. In the solution state, the reaction time is preferably in the range of 10 minutes to 5 hours, more preferably in the range of 30 minutes to 2 hours.

[0325] Considering processability and physical properties, the weight average molecular weight (in terms of polystyrene) of the modified conjugated diene copolymer of the present invention is preferably 100,000 to 2,000,000, and more preferably 150,000 to 1,000,000. The weight average molecular weight can be determined by measuring the chromatogram using a gel permeation chromatograph (GPC) using a column filled with polystyrene gel and by using a calibration curve using standard polystyrene.

[0326] Regarding the composition of the structural unit of the modified conjugated diene-based copolymer of the present invention, when no aromatic vinyl compound (C) is used, the ratio of the polyfunctional vinyl aromatic copolymer (A) to the conjugated diene compound (B) is preferably within the following range.

[0327] The content of the structural unit (A1) derived from the modified vinyl aromatic copolymer (A) having the structural unit (c) containing the silane functional group represented by the formula (2) and / or the formula (3) is 0.001 to 6% by weight, preferably 0.001 to 5% by weight, more preferably 0.005 to 5% by weight, further preferably 0.01 to 5% by weight, and most preferably 0.001 to 1% by weight. The content of the structural unit (B1) derived from the conjugated diene compound (B) is 29 to 99.999% by weight, preferably 80 to 99.999% by weight, more preferably 90 to 99.995% by weight, and further preferably 95 to 99.99% by weight.

[0328] When an aromatic vinyl compound (C) is used, the ratio is preferably set to the following range. The structural unit (A1) is the same range as above, and the structural unit (B1) is 30% by weight to 97.999% by weight, preferably 45% by weight to 94.995% by weight, and more preferably 55% by weight to 89.99% by weight. The structural unit (C1) derived from the aromatic vinyl compound (C) is 2% by weight to 50% by weight, preferably 5% by weight to 45% by weight, and more preferably 10% by weight to 40% by weight.

[0329] In addition, the microstructure (cis bond, trans bond, vinyl bond amount) of the modified conjugated diene copolymer can be arbitrarily changed by using polar compounds, etc., but in the state before the terminal is modified, the content of vinyl bond (1,2-bond) in the conjugated diene unit is preferably 10 mol% to 80 mol%. In the case where the modified conjugated diene copolymer of the present invention is made into a rubber composition described later and further cross-linked and used as a tire for automobiles, in order to balance the rolling resistance performance with the wear resistance, the content is preferably 20 mol% to 75 mol%, more preferably 30 mol% to 75 mol%, and further preferably 40 mol% to 70 mol%. At this time, the mass ratio of cis bond to trans bond in the conjugated diene bond unit is preferably cis bond / trans bond=1 / 1.1 to 1.5.

[0330] A reaction terminator may be added to the polymer solution of the modified conjugated diene copolymer obtained by the polymerization method as needed. Examples of the reaction terminator include alcohols such as methanol, ethanol, and propanol; organic acids such as stearic acid, lauric acid, and caprylic acid; and water.

[0331] In addition, after the polymerization reaction of the modified conjugated diene copolymer is carried out, the metals contained in the polymer may be deashed as needed. As a method for deashing, for example, a method of bringing water, an organic acid, an inorganic acid, an oxidizing agent such as hydrogen peroxide into contact with the polymer solution to extract the metals, and then separating the water layer is used.

[0332] 〔Post-processing〕

[0333] As described above, when the modified conjugated diene polymer with terminal modification and main chain modification is obtained in the form of a solution, an antioxidant and an additive may be added as needed, and then the solvent may be removed and dried by a common method. Thus, the raw material of the rubber composition described later may be prepared. Specifically, the method of steam stripping and dehydration drying, the direct stripping method by a drum dryer, flashing, and an extrusion extruder, etc.

[0334] As antioxidant, there is no particular limitation, and known antioxidants can be used. As antioxidant, phenol stabilizer, phosphorus stabilizer, sulfur stabilizer, etc. can be cited. Specifically, for example, antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol) propionate, 2-methyl-4,6-bis[(octylthio)methyl]phenol are preferred.

[0335] In addition, if necessary, in order to remove or neutralize ionic substances, as additives, water, alcohols such as methanol, ethanol, and isopropanol, or carboxylic acids such as stearic acid, oleic acid, myristic acid, lauric acid, capric acid, citric acid, and malic acid, aqueous inorganic acid solutions, carbon dioxide, etc. may be added.

[0336] The modified conjugated diene copolymer of the present invention may have an area of ​​10% or more of a number average molecular weight (Mn) three times or more of the peak on the lowest molecular weight side in a differential molecular weight distribution curve obtained by GPC measurement, when the total area is 100%.

[0337] Reference Figure 1 This is explained.

[0338] Figure 1 The typical example of the GPC dissolution curve, the position of the peak top Mp and the molecular weight 3Mp three times the peak top are shown. The number average molecular weight 3Mp region ( Figure 1 The area of ​​the region to the right of 3Mp in the graphite matrix can be 10% by area or more. This means that there are many high molecular weight components.

[0339] The modified vinyl aromatic copolymer (A) of the present invention can be used as a modified purpose of the rubber composition. By mixing the copolymer (A) into the rubber composition, the processability of the rubber composition becomes good. In addition, the affinity of the reinforcing filler in the obtained rubber composition is improved, so it is easy to exist near the reinforcing filler when making the rubber composition. As a result, it is inferred that the dispersion state of the reinforcing filler in the rubber composition is ideal for improving the physical properties of the obtainable cross-linked product (for example, anti-dry skid performance, anti-wet skid performance). In addition, the branched polymer-type modified group based on the modified vinyl aromatic copolymer is easy to exist near the reinforcing filler, and as a result, a cross-linked product with excellent wear resistance can be obtained.

[0340] Next, the modified conjugated diene copolymer composition (hereinafter also referred to as rubber composition) of the present invention will be described.

[0341] The rubber composition contains the modified conjugated diene polymer and a filler.

[0342] Another embodiment of the rubber composition of the present invention contains 0.5 to 200 parts by mass of a reinforcing filler relative to 100 parts by mass of the modified conjugated diene polymer.

[0343] Another embodiment of the rubber composition of the present invention contains 100 parts by mass of a raw rubber containing 20 parts by mass or more of the modified conjugated diene polymer and 5 parts by mass to 200 parts by mass of a filler.

[0344] 〔Raw material rubber〕

[0345] The modified conjugated diene polymer content in 100 parts by mass of raw rubber is more than 20 parts by mass, preferably more than 40 parts by mass, more preferably more than 50 parts by mass, and further preferably more than 60 parts by mass. If more than 20 parts by mass, the target dispersibility of the present invention is excellent. When the rubber composition of the present embodiment is used as a vulcanized composition, the performances such as tensile properties and viscoelastic properties are excellent. When used as a tire material, excellent fuel consumption performance, grip performance, wear resistance, and rigidity can be obtained. In addition, the content of the modified conjugated diene polymer is preferably less than 90 parts by mass, more preferably less than 80 parts by mass. By making it less than 90 parts by mass, the Mooney viscosity (Mooney viscosity) of the unvulcanized modified conjugated diene copolymer composition of the present invention is reduced, and processability is improved.

[0346] The raw material rubber other than the modified butadiene polymer is not particularly limited, and examples thereof include: conjugated diene polymers or hydrogenated products thereof, random copolymers of conjugated diene compounds and vinyl aromatic compounds or hydrogenated products thereof, block copolymers of conjugated diene compounds and vinyl aromatic compounds or hydrogenated products thereof, other conjugated diene copolymers or hydrogenated products thereof, non-diene polymers, natural rubber, etc.

[0347] Specific examples of the conjugated diene polymer or its hydrogenated product are not particularly limited, and examples thereof include butadiene rubber or its hydrogenated product, isoprene rubber or its hydrogenated product, and the like.

[0348] Specific examples of the random copolymer of a conjugated diene compound and a vinyl aromatic compound or a hydrogenated product thereof are not particularly limited, and examples thereof include styrene-butadiene copolymer rubber and a hydrogenated product thereof.

[0349] Specific examples of the block copolymer of a conjugated diene compound and a vinyl aromatic compound or a hydrogenated product thereof are not particularly limited, and examples thereof include styrene-based elastomers such as a styrene-butadiene block copolymer or a hydrogenated product thereof and a styrene-isoprene block copolymer or a hydrogenated product thereof.

[0350] Specific examples of other conjugated diene copolymers or hydrogenated products thereof are not particularly limited, and examples thereof include acrylonitrile-butadiene rubber or hydrogenated products thereof.

[0351] In addition, the non-diene polymer is not particularly limited, and examples thereof include olefin elastomers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber, butyl rubber, brominated butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α, β-unsaturated nitrile-acrylate-conjugated diene copolymer rubber, urethane rubber, and polysulfide rubber.

[0352] In the present invention, when the modified conjugated diene polymer is a modified styrene-butadiene rubber, the other rubber is preferably polybutadiene. In addition, when the modified butadiene polymer is a modified polybutadiene, the other rubber is preferably natural rubber or polyisoprene rubber.

[0353] From the viewpoint of the balance between performance and processing characteristics, the weight average molecular weight of the various rubbery polymers is preferably 2,000 to 2,000,000, more preferably 5,000 to 1,500,000. In addition, so-called liquid rubbers of low molecular weight may also be used. These rubbery polymers may be used alone or in combination of two or more. The weight average molecular weight referred to herein is the weight average molecular weight (Mw) of polystyrene conversion obtained by gel permeation chromatography (GPC).

[0354] Regarding the amount of filler used relative to the raw rubber, if more filler is used, the hardness and modulus will increase, and the desired physical properties are achieved by adjustment according to the application. If it is within the above range, the dispersibility of the filler is good and the processability is good. In tire applications, the filler is preferably 5 to 150 parts by mass, and in shoe applications, it is preferably 30 to 200 parts by mass. Within the scope of this embodiment, a wide range of applications from soft to hard can be handled.

[0355] 〔Reinforcing fillers〕

[0356] In another embodiment of the rubber composition of the present invention, the rubber composition preferably contains 0.5 to 200 parts by mass of at least one reinforcing filler selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides and carbon black, based on 100 parts by mass of the modified conjugated diene polymer, based on 100 parts by mass of the raw rubber.

[0357] As the silica-based inorganic filler contained in the rubber composition, it is preferred to use solid particles having SiO2 or silicate as the main component of the constituent unit. Here, the so-called main component refers to a component accounting for 50% by mass or more of the whole, preferably a component accounting for 70% by mass or more, and more preferably a component accounting for 90% by mass or more.

[0358] As the specific example of silica-based inorganic filler, it is possible to enumerate inorganic fibrous materials such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, glass fiber, etc. The silica-based inorganic filler can be used alone or in combination of two or more. In addition, it is also possible to use a mixture of the silica-based inorganic filler, the silica-based inorganic filler and the inorganic filler other than the silica-based inorganic filler that has been hydrophobized on the surface. Among these, preferably silica and glass fiber, more preferably silica.

[0359] As silica, dry silica, wet silica, synthetic silicate silica and the like can be used. Among these, wet silica is preferred in terms of achieving both improved fracture characteristics and wet skid resistance.

[0360] The rubber composition of the present invention may be used in combination with other reinforcing fillers. Due to the combined effects of various functional groups of the modified conjugated diene copolymer of the present invention, the dispersion of both silica and other reinforcing fillers is improved, and an excellent reinforcing effect can be obtained.

[0361] As the silica used as the reinforcing filler, a Brunauer-Emmett-Teller (BET) silica having a specific surface area of ​​50 m 2 / g~500m 2 By blending this silica, excellent low fuel consumption, wear resistance, wet skid resistance and handling stability can be achieved.

[0362] In the rubber composition of the present invention, the dispersibility of silica is good, and therefore, even when silica having a high specific surface area, that is, silica having a fine particle size is used, it can be dispersed well.

[0363] The silica-based inorganic filler may be micro-particle silica. The micro-particle silica may contain cetyltrimethylammonium bromide (CTAB) with a specific surface area of ​​180 m 2 / g or more, BET specific surface area of ​​185m 2 By blending such fine particle size silica, a rubber composition having excellent low fuel consumption, wear resistance, wet skid resistance and handling stability can be obtained.

[0364] The CTAB (cetyltrimethylammonium bromide) specific surface area of ​​the fine particle size silica is not particularly limited, but is preferably 190 m 2 / g or more, more preferably 195m 2 / g or more, more preferably 197m 2 / g or more. CTAB specific surface area is 180m 2 When the specific surface area is greater than 500 m / g, a rubber composition having excellent wear resistance can be obtained. The upper limit of the specific surface area is not particularly limited, but is preferably 500 m 2 / g or less, more preferably 300m 2 / g or less, and more preferably 250m 2 / g or less. CTAB specific surface area is 500m 2 When the CTAB specific surface area is less than 190 m / g, a rubber composition with excellent processability can be obtained. 2 / g~300m 2 In addition, the CTAB specific surface area is measured according to American Society for Testing and Materials (ASTM) D3765-92.

[0365] The BET specific surface area of ​​the silica particle size is not particularly limited, but is preferably 190 m 2 / g or more, more preferably 195m 2 / g or more, more preferably 210m 2 / g or more. When the BET specific surface area is 185m 2 When the BET specific surface area is greater than 500 m / g, a rubber composition having excellent wear resistance can be obtained. The upper limit of the BET specific surface area is not particularly limited, but is preferably 500 m 2 / g or less, more preferably 300m 2 / g or less, and more preferably 260m 2 / g or less. When the BET specific surface area is 500m 2 When the ratio is 1:1 to 1:1, a modified conjugated diene copolymer composition having excellent processability can be obtained. The BET specific surface area of ​​silica is measured in accordance with ASTM D3037-81.

[0366] The aggregate size of the microparticle diameter silica is not particularly limited, and can be 30nm or more, preferably 35nm or more, more preferably 40nm or more, and further preferably 45nm or more, and further preferably 50nm or more, and further preferably 55nm or more. In addition, the aggregate size is not particularly limited, and is preferably 100nm or less, more preferably 80nm or less, and further preferably 70nm or less, and particularly preferably 65nm or less. By having such an aggregate size, excellent reinforcement, low fuel consumption, wear resistance, anti-wet skid performance and handling stability can be given while having good dispersibility. The aggregate size is also referred to as the agglomerate diameter or the maximum frequency Stokes equivalent diameter, which is equivalent to the particle size when the agglomerate of silica composed of multiple primary particles is regarded as one particle. The aggregate size can be measured, for example, using a disc centrifugal sedimentation particle size distribution measuring device such as Brookhaven Instruments Corporation (manufactured by BI-XDC). Specifically, it can be measured by the method described in Japanese Patent Laid-Open No. 2011-132307.

[0367] The average primary particle size of the micro-particle diameter silica is not particularly limited, preferably 25nm or less, more preferably 22nm or less, and further preferably 17nm or less, particularly preferably 14nm or less. The lower limit of the average primary particle size is not particularly limited, preferably 3nm or more, more preferably 5nm or more, and further preferably 7nm or more. If within the range, the dispersibility and reinforcement are excellent. Furthermore, the average primary particle size of the micro-particle diameter silica can be observed using a transmission or scanning electron microscope, and more than 400 primary particles of silica observed in the field of view are measured, and the average is obtained.

[0368] The amount of the micro-particle diameter silica in the rubber composition of the present invention is not particularly limited, and relative to 100 parts by mass of rubber components, it is preferably 5 parts by mass or more, more preferably 15 parts by mass or more, and further preferably 20 parts by mass or more, and further preferably 25 parts by mass or more, and further particularly preferably 30 parts by mass or more. If it is 5 parts by mass or more, the effect of the micro-particle diameter silica can be fully obtained. The upper limit of the amount of micro-particle diameter silica is less than 200 parts by mass, preferably less than 100 parts by mass, more preferably less than 80 parts by mass, and further preferably less than 60 parts by mass, and further preferably less than 55 parts by mass. If it is less than 200 parts by mass, substantially good processability can be obtained.

[0369] The rubber composition of the present invention may preferably further contain 5 to 100 parts by mass of a compound having a BET specific surface area of ​​less than 185 m 2 / g of silica or carbon black as reinforcing filler.

[0370] Furthermore, as a reinforcing filler, it is preferred to use a nitrogen adsorption specific surface area (N2SA) of less than 185 m 2 / g of silica, and preferably less than 150m 2 / g of silica, preferably 50m 2 / g or more of silica. Within the above range, the balance between reinforcement and dispersibility is good. In addition, silica with a suitable particle size can be used according to the application.

[0371] Carbon black includes N110, N220, N330, N339, N550, N660, etc., according to the classification of carbon black for rubber based on ASTM. The carbon black is selected according to the application. By using carbon black in combination, the reinforcement can be improved, and when used for tire tread, the anti-dry skid performance can be improved. The nitrogen adsorption specific surface area (N2SA) of carbon black using the BET method is preferably less than 185 m 2 / g of carbon black, preferably 30m 2 / g or more, more preferably 50m 2 / g~130m 2 In the above range, the balance between reinforcement and dispersibility is good. When used for tire treads, N220, N330, and N339 are more preferred.

[0372] As reinforcing fillers, in addition to the above-mentioned silicon dioxide, other reinforcing fillers can also be used. As other reinforcing fillers, there are no special restrictions. The metal oxide used as a reinforcing filler is preferably a solid particle with a component having a chemical formula MxOy (M represents a metal atom, and x and y represent integers of 1 to 6 respectively) as the main component. Here, the so-called main component refers to a component that accounts for more than 50% by mass of the whole, preferably a component that accounts for more than 70% by mass, and more preferably a component that accounts for more than 90% by mass.

[0373] As the metal oxide, for example, aluminum oxide, titanium oxide, magnesium oxide, zinc oxide or the like can be used.

[0374] Examples of the metal hydroxide as the reinforcing filler include aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

[0375] The metal oxides or metal hydroxides as the other reinforcing fillers may be used alone or in combination of two or more, or may be used as a mixture with other inorganic fillers.

[0376] In addition, a silane coupling agent can be used in the rubber composition of the present invention. The silane coupling agent is not particularly limited, and is a compound having both a silica affinity portion and a polymer affinity portion in the molecule, and examples thereof include sulfide compounds, mercapto compounds, vinyl compounds, amino compounds, glycidyloxy compounds, nitro compounds, and chlorine compounds.

[0377] Examples of the sulfide-based compound include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-trimethoxysilylpropyl)trisulfide, bis(3-trimethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, 3-trimethoxysilylpropyl-N- ,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylmethacrylate monosulfide, 3-trimethoxysilylpropylmethacrylate monosulfide, 3-octanoylthio-1-propyltriethoxysilane, etc.

[0378] As a mercapto-type compound, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane etc. are mentioned, for example.

[0379] As a vinyl compound, vinyltriethoxysilane, vinyltrimethoxysilane, etc. are mentioned, for example.

[0380] As an amino-type compound, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane etc. are mentioned, for example.

[0381] Examples of the glycidyloxy compound include γ-glycidyloxypropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropylmethyldiethoxysilane, and γ-glycidyloxypropylmethyldimethoxysilane.

[0382] Examples of the nitro compound include 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane.

[0383] As a chlorine-based compound, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane etc. are mentioned, for example.

[0384] As another compound, octyltriethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, hexadecyltrimethoxysilane etc. are mentioned, for example.

[0385] These silane coupling agents may be used alone or in combination of two or more. Among these silane coupling agents, from the viewpoint of having a large self-reinforcement effect, silane coupling agents containing sulfur such as sulfide compounds and mercapto compounds are preferred, and bis(3-triethoxysilylpropyl)disulfide, bis(3-triethoxysilylpropyl)tetrasulfide, and 3-mercaptopropyltrimethoxysilane are more preferred.

[0386] The amount of the silane coupling agent is 1 to 20 parts by mass, preferably 2 to 15 parts by mass, relative to 100 parts by mass of silica. If the silane coupling agent is mixed within the above range, the dispersibility of silica is further improved, the processability is improved, the wear resistance is further improved, and the performance of the vulcanized rubber is improved.

[0387] In addition, in the rubber composition of the present invention, hardness and modulus can be adjusted by using a plasticizer. As the plasticizer, there is no particular limitation, for example, the same oil as the stretching oil can be used, in addition to which various natural oils, synthetic oils, low molecular weight polymers, etc. can also be used. In addition, known processing aids can also be used.

[0388] (Crosslinking agent)

[0389] The rubber composition of the present invention may be a rubber composition further subjected to a crosslinking treatment by adding a crosslinking agent, a compounding agent, etc. Such a crosslinking agent is not particularly limited, and for example, a sulfur-based vulcanizing agent, an organic peroxide, etc. may be used.

[0390] The sulfur-based vulcanizing agent is not particularly limited, and for example, sulfur and morpholine disulfide can be used. The organic peroxide can be, for example, benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, tert-butylcumyl peroxide, and cumene hydroperoxide.

[0391] In addition, a vulcanization accelerator may be formulated as needed. The vulcanization accelerator is not particularly limited, and for example, at least one of sulfenamide-based, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamate-based, aldehyde-amine-based or aldehyde-ammonia-based, imidazoline-based, or xanthate-based vulcanization accelerators may be used.

[0392] Furthermore, a vulcanization aid may be mixed as needed. The vulcanization aid is not particularly limited, and for example, zinc oxide, stearic acid, etc. may be used. In addition, an anti-aging agent may also be used.

[0393] The modified conjugated diene-based copolymer composition of the present invention can be produced by mixing the above-mentioned components.

[0394] There is no particular limitation on the method of mixing the modified conjugated diene copolymer with at least one reinforcing filler selected from the group consisting of a silica-based inorganic filler, a metal oxide, a metal hydroxide and carbon black, and a desired silane coupling agent. For example, there can be cited: a melt kneading method using a general mixer such as an open roll, a Banbury mixer, a kneader, a single-axis screw extruder, a twin-axis screw extruder, and a multi-axis screw extruder; a method of melting and mixing each component and then heating to remove the solvent, etc. Among these, from the perspective of productivity and good kneading properties, a melt kneading method using a roll, a Banbury mixer, a kneader, and an extruder is preferred. In addition, any method of a method of kneading the rubber component with various formulations at one time or a method of mixing in multiple times can be applied.

[0395] In the present invention, the degree of polymer concentration ability on the filler surface can be represented by the bound rubber amount of the modified conjugated diene polymer at 25° C. From the viewpoint of improving wear resistance and breaking strength, the bound rubber amount in the rubber composition after kneading is preferably 15% by mass or more, more preferably 20% by mass or more.

[0396] The rubber composition may be a vulcanized composition subjected to vulcanization treatment using a vulcanizing agent. As the vulcanizing agent, for example, free radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds may be used. Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, and high molecular weight polysulfide compounds.

[0397] The amount of the vulcanizing agent used is not particularly limited, but is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, relative to 100 parts by mass of the conjugated diene copolymer. As a vulcanization method, a conventionally known method can be applied, and the vulcanization temperature is, for example, preferably 120°C to 200°C, more preferably 140°C to 180°C.

[0398] During vulcanization, a vulcanization accelerator may be used as necessary. As the vulcanization accelerator, conventionally known materials may be used, for example, sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, dithiocarbamate-based vulcanization accelerators may be mentioned. As the vulcanization aid, zinc white, stearic acid, etc. may be used.

[0399] The amount of the vulcanization accelerator used is not particularly limited, but is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, based on 100 parts by mass of the conjugated diene copolymer.

[0400] The rubber composition of the present invention may contain a rubber softener in order to improve processability. The rubber softener is preferably a mineral oil or a liquid or low molecular weight synthetic softener.

[0401] The mineral oil-based rubber softener called process oil or extender oil used to soften, increase volume, and improve processability of rubber is a mixture of aromatic rings, cycloalkane rings, and paraffin chains. The carbon number of the paraffin chain accounts for more than 50% of all carbons and is called a paraffin series, the carbon number of the cycloalkane ring is 30% to 45% and the aromatic carbon number is more than 30%. The rubber softener used in this embodiment is preferably a cycloalkane-based and / or paraffin-based rubber softener.

[0402] The amount of the rubber softener to be added is not particularly limited, but is preferably 10 to 80 parts by mass, more preferably 20 to 50 parts by mass, based on 100 parts by mass of the conjugated diene copolymer.

[0403] In the rubber composition, various additives such as softeners or fillers other than those mentioned above, as well as heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, lubricants, etc. can be used within the range that does not impair the purpose of the present embodiment. As fillers, specifically, calcium carbonate, magnesium carbonate, aluminum sulfate, barium sulfate, etc. can be cited.

[0404] As a softener which is mixed as needed to adjust the hardness or fluidity of the target product, for example, there can be mentioned liquid paraffin, castor oil, linseed oil, etc. As a heat stabilizer, antistatic agent, weather stabilizer, anti-aging agent, colorant, lubricant, known materials can be applied.

[0405] The cross-linked rubber of the present invention can be obtained by cross-linking the rubber composition of the present invention formulated with a cross-linking agent.

[0406] The tire components of the present invention are obtained from a cross-linked rubber. For example, in the case of a tire, the rubber composition can be extruded and formed according to the shape of the tire (specifically, the shape of the tread), and heated and pressurized in a vulcanizer to manufacture the tread, and the target tire can be manufactured by assembling the tread with other parts.

[0407] The rubber composition of the present invention has excellent mechanical strength and wear resistance when it is made into a rubber cross-linked product. Therefore, as mentioned above, it can be suitably applied to tire components such as the tread or the outer tire side member of a tire such as a low fuel consumption tire, a large tire, and a high-performance tire. In addition, it can be not only applicable to the tire components, but also suitably used in rubber belts, rubber hoses, materials for footwear, etc.

[0408] Example

[0409] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In addition, parts in each example are parts by weight unless otherwise specified, and evaluation of various physical properties was performed by the methods shown below.

[0410] 1) Molecular weight and molecular weight distribution

[0411] The molecular weight and molecular weight distribution were measured using GPC (HLC-8220GPC manufactured by Tosoh Corporation) with tetrahydrofuran (THF) as a solvent, at a flow rate of 1.0 ml / min, a column temperature of 38° C., and a calibration curve obtained using monodisperse polystyrene.

[0412] 2) Structure of multifunctional vinyl aromatic copolymer

[0413] The JNM-LA600 nuclear magnetic resonance spectrometer manufactured by JEOL was used. 13 C-NMR and 1 The determination was made by H-NMR analysis using chloroform-d1 as a solvent and the resonance line of tetramethylsilane as an internal standard.

[0414] 3) Mooney viscosity (ML(1+4)100℃)

[0415] The value was determined in accordance with Japanese Industrial Standards (JIS) K6300-1, with an L-shaped rotor, 1 minute preheating, 4 minutes rotor operation time, and a temperature of 100°C.

[0416] Haze

[0417] A sample prepared by dissolving 0.5 g of the copolymer in 100 g of toluene was placed in a quartz cell, and the haze value was measured using an integrating sphere light transmittance measuring device (SZ-Σ90 manufactured by Nippon Denshoku Co., Ltd.) with toluene as a reference sample.

[0418] 5) Glass transition temperature (Tg)

[0419] The solution obtained by dissolving the polyfunctional vinyl aromatic copolymer in toluene is uniformly coated on a glass substrate in such a manner that the thickness after drying becomes 20 μm, and is dried by heating at 90° C. for 30 minutes using a hot plate. The glass substrate is placed in a thermomechanical analyzer (TMA) (thermomechanical analysis device) together with the obtained resin film, and the temperature is raised to 220° C. at a heating rate of 10° C. / min under a nitrogen gas flow, and then heated at 220° C. for 20 minutes to remove the remaining solvent and harden the polyfunctional vinyl aromatic copolymer. After the glass substrate is placed and cooled to room temperature, the analysis probe is contacted with the sample in the TMA measuring device, and the scanning measurement is performed from 30° C. to 360° C. at a heating rate of 10° C. / min under a nitrogen gas flow, and the softening temperature is obtained by the tangent method.

[0420] 6) Solvent solubility

[0421] The copolymer was soluble in toluene, xylene, THF, dichloroethane, dichloromethane and chloroform, and the case where 100 g or more of the copolymer was dissolved in 100 g of each of the above solvents and no formation of gel was observed was regarded as solvent solubility (○).

[0422] 7) Vinyl bond content of conjugated diene units in conjugated diene copolymers

[0423] The sample was made into a carbon disulfide solution and the solution was heated at 600 cm -1 ~1000cm -1 The infrared spectrum was measured within a range of , and the amount of vinyl bonds was determined using the absorbance at a predetermined wave number according to the calculation formula of the Hampton (styrene-butadiene copolymer) method. The apparatus used was Spectrum 100 manufactured by Parkin Elmer.

[0424] 8) Combined rubber content (%)

[0425] Using a closed kneading apparatus with a kneading chamber volume of 2 liters, 100 parts by mass of the modified conjugated diene polymer and 60 parts by mass of wet silica (BET specific surface area: 205±10 m 2 / g, manufactured by Tosoh Silica Co., Ltd., trade name "Nipsil AQ") was kneaded, and when the maximum kneading temperature reached 160°C, the rubber kneaded product was discharged to obtain a rubber composition M for measuring the bound rubber amount.

[0426] 0.2 g of the rubber composition M was cut into 1 mm squares and the mass was measured, then added to 25 mL of toluene and allowed to stand at 25° C. for 48 hours. The mixture was filtered using a glass fiber filter manufactured by ADVANTEC to separate the toluene-insoluble components. The separated toluene-insoluble components were then vacuum dried at 25° C. and weighed, and the bound rubber amount was calculated using the following formula.

[0427] Bound rubber amount (%) = {(mass of toluene insoluble components - mass of wet silica in rubber composition M) / (mass of rubber composition M - mass of wet silica in rubber composition M)} × 100

[0428] The BET specific surface area of ​​silica is measured in accordance with International Organization for Standardization (ISO) 5794 / 1.

[0429] 9) Tensile strength

[0430] The 300% modulus was measured by the tensile test method of JIS K6251, and the measured value of the cross-linked rubber obtained in Example 7 was set to 100 for indexing. A larger index value indicates better tensile strength.

[0431] 10) Wear resistance

[0432] The wear amount at a slip ratio of 30% was measured using a Lambourn type wear tester in accordance with JIS K6264, and the measured value of the crosslinked rubber obtained in Example 10 was set to 100 for indexing. A larger index value indicates better wear resistance.

[0433] The raw materials or their abbreviations used in the examples are as follows.

[0434] DVB-630: a mixture of divinyl benzene (DVB) and ethylvinyl benzene (EVB), DVB and EVB are (a mixture of an intermediate and a counter-isomer); DVB content 63.0 wt%, manufactured by NIPPON STEEL Chemical & Material)

[0435] BHT: 2,6-di-tert-butyl-p-cresol

[0436] BTESPA: Bis(3-trimethoxysilylpropyl)methylamine

[0437] Synthesis example 1

[0438] 31.00 g of DVB-630 (0.150 mol of DVB, 0.088 mol of EVB), 65.72 g (0.631 mol) of styrene, 70.80 g (0.631 mol) of diisobutylene, 60 mmol (6.90 mL) of n-propyl acetate, and 48.55 g (0.527 mol) of toluene were placed in a 500 mL reactor, 15.2 mmol of boron trifluoride diethyl ether complex (1.91 mL) was added at 70° C., and the reaction was carried out for 2.0 hours. After the polymerization was stopped with an aqueous sodium bicarbonate solution, the oil layer was washed three times with pure water, and the copolymer was recovered under reduced pressure at 60° C. to obtain 60.6 g of a multifunctional vinyl aromatic copolymer (copolymer A-1).

[0439] The Mn of copolymer A-1 is 941, the Mw is 2850, and the Mw / Mn is 3.03. In addition, it contains 19.0 mol% (21.8wt%) of structural units derived from DVB, 8.3 mol% (9.6wt%) of structural units derived from EVB, 48.6 mol% (44.6wt%) of structural units derived from styrene, and 24.2 mol% (24.0wt%) of structural units derived from diisobutylene. The cross-linked structural unit (a1) is 4.6 mol% (5.2wt%), and the degree of cross-linking (a1 / a) is 0.24. In addition, the structural unit (a2) having residual vinyl groups is 14.4 mol% (16.5wt%), and the molar fraction of the structural unit (a2) relative to the total of the structural units (a), (b) and (c) is 0.144.

[0440] The Tg of the cured product was 167° C., and the softening temperature was 280° C. or higher. The weight loss at 350° C. was 1.41 wt %.

[0441] In addition, a sample prepared by dissolving 0.5 g of the polyfunctional vinyl aromatic copolymer (A-1) in 100 g of toluene was placed in a quartz cell. The haze (turbidity) thereof was measured using an integrating sphere light transmittance measuring device with toluene as the reference sample. The haze value was 0.02.

[0442] Example 1

[0443] 50.0 g of the copolymer A-1 and 50.0 g of ethylcyclohexane were added to a 300 mL three-necked flask, and the mixture was degassed with nitrogen while being stirred at 60° C. for 3 hours. 0.032 g of tert-butyl peroxy 2-ethylhexanoate and 30.6 g of (3-mercaptopropyl) trimethoxysilane (MPTMS) were added, and the mixture was reacted at 90° C. for 8 hours to obtain 80.6 g of a modified vinyl aromatic copolymer (copolymer A-2) in terms of solid content.

[0444] Example 2

[0445] In an autoclave reactor purged with nitrogen, 200 g of cyclohexane and 5 g of a cyclohexane solution containing 6.2 mg (0.032 mmol) of 2,2-di(2-tetrahydrofuryl)propane were placed, and 5 g of a cyclohexane solution containing 10 mg (0.16 mmol) of n-butyl lithium was added at 50° C. Then, 10 g of styrene and 40 g of 1,3-butadiene from which impurities had been removed were added to start polymerization. The temperature of the reaction solution rose due to the polymerization heat, and the maximum temperature reached 81° C.

[0446] After the polymerization reaction, 5 g of a cyclohexane solution containing 0.031 g of the copolymer A-2 obtained in Example 1 was added to the reactor as a modifier to carry out a modification reaction at 50° C. for 30 minutes to obtain a polymer solution.

[0447] Furthermore, 0.08 mmol of BTESPA was added and the reaction was allowed to proceed for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.

[0448] After adding 0.045 g of 2,6-di-tert-butyl-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the solution was vacuum dried to obtain a modified conjugated diene copolymer (copolymer A-3).

[0449] Synthesis example 2

[0450] 46.49 g of DVB-630 (0.225 mol of DVB, 0.132 mol of EVB), 53.33 g (0.512 mol) of styrene, 70.80 g (0.631 mol) of diisobutylene, 60 mmol (6.90 mL) of n-propyl acetate, and 48.55 g (0.527 mol) of toluene were placed in a 500 mL reactor, 10.0 mmol of boron trifluoride diethyl ether complex (1.26 mL) was added at 70° C., and the reaction was carried out for 2.0 hours. After the polymerization was stopped with an aqueous sodium bicarbonate solution, the oil layer was washed three times with pure water, and the copolymer was decompressed and devolatilized at 60° C., and 66.4 g of a multifunctional vinyl aromatic copolymer (copolymer B-1) was obtained.

[0451] The Mn of copolymer B-1 is 1240, the Mw is 4980, and the Mw / Mn is 4.02. In addition, it contains 28.2 mol% (31.5 wt%) of structural units derived from DVB, 12.2 mol% (13.8 wt%) of structural units derived from EVB, 37.6 mol% (33.6 wt%) of structural units derived from styrene, and 22.0 mol% (21.1 wt%) of structural units derived from diisobutylene. In addition, the crosslinked structural unit (a1) is 7.6 mol% (8.5 wt%), and the degree of crosslinking is 0.27. In addition, the structural unit (a2) is 20.6 mol% (23.0 wt%), and the molar fraction of the structural unit (a2) is 0.206.

[0452] The Tg of the cured product was 176° C., the softening temperature was 280° C. or higher, and the weight loss at 350° C. was 1.32 wt %. The haze value was 0.03.

[0453] Example 3

[0454] 50.0 g of the copolymer B-1 obtained in Synthesis Example 2 and 50.0 g of ethylcyclohexane were added to a 300 mL three-necked flask, and the mixture was degassed with nitrogen while being stirred at 60° C. for 3 hours. 0.036 g of tert-butyl peroxy 2-ethylhexanoate and 34.5 g of (3-mercaptopropyl)trimethoxysilane were added, and the mixture was reacted at 90° C. for 8 hours to obtain 84.5 g of a modified vinyl aromatic copolymer (copolymer B-2) in terms of solid content.

[0455] Example 4

[0456] In a nitrogen-substituted autoclave reactor, 200 g of cyclohexane, 5 g of a cyclohexane solution containing 6.2 mg (0.032 mmol) of 2,2-di(2-tetrahydrofuranyl)propane, and 5 g of a cyclohexane solution containing 10 mg (0.16 mmol) of n-butyl lithium in purity were added at 50°C, and then 10 g of styrene and 40 g of 1,3-butadiene from which impurities had been removed were added to start polymerization. The temperature of the reaction solution rose due to the heat of polymerization, and the maximum temperature reached 81°C. After the polymerization reaction was completed, 5 g of a cyclohexane solution containing 0.027 g of the copolymer B-2 obtained in Example 3 was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 50°C for 30 minutes to obtain a polymer solution.

[0457] Furthermore, 0.08 mmol of BTESPA was added and the reaction was allowed to proceed for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.

[0458] After adding 0.045 g of 2,6-di-tert-butyl-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the solution was vacuum dried to obtain a modified conjugated diene copolymer (copolymer B-3).

[0459] Synthesis example 3

[0460] 62.00 g of DVB-630 (0.300 mol of DVB, 0.176 mol of EVB), 40.92 g (0.393 mol) of styrene, 70.80 g (0.631 mol) of diisobutylene, 60 mmol (6.90 mL) of n-propyl acetate, and 48.55 g (0.527 mol) of toluene were placed in a 500 mL reactor, and 8.2 mmol of boron trifluoride diethyl ether complex (1.03 mL) was added at 70° C., and the reaction was carried out for 1.5 hours. After the polymerization was stopped with an aqueous sodium bicarbonate solution, the oil layer was washed three times with pure water, and the copolymer was recovered under reduced pressure at 60° C. to obtain 56.3 g of a multifunctional vinyl aromatic copolymer (copolymer C-1).

[0461] The obtained copolymer C-1 has an Mn of 1430, an Mw of 5490, and an Mw / Mn of 3.84. In addition, it contains 39.4 mol% (42.6 wt%) of structural units derived from DVB, 15.9 mol% (17.4 wt%) of structural units derived from EVB, 25.7 mol% (22.2 wt%) of structural units derived from styrene, and 19.1 mol% (17.8 wt%) of structural units derived from diisobutylene. The crosslinked structural unit (a1) is 11.4 mol% (12.3 wt%), and the degree of crosslinking is 0.29. In addition, the structural unit (a2) is 28.0 mol% (30.2 wt%), and its molar fraction is 0.280.

[0462] The Tg of the cured product was 183° C., and the softening temperature was 280° C. or higher. The weight loss at 350° C. was 1.28 wt %. The haze value was 0.05.

[0463] Example 5

[0464] 50.0 g of the copolymer C-1 obtained in the synthesis example and 50.0 g of ethylcyclohexane were added to a 300 mL three-necked flask, and the mixture was degassed with nitrogen while being stirred at 60° C. for 3 hours. 0.044 g of tert-butyl peroxy 2-ethylhexanoate and 42.3 g of (3-mercaptopropyl)trimethoxysilane (MPTMC) were added, and the mixture was reacted at 90° C. for 8 hours to obtain 92.3 g of a modified vinyl aromatic copolymer (copolymer C-2) in terms of solid content.

[0465] Example 6

[0466] In a nitrogen-substituted autoclave reactor, 200 g of cyclohexane, 5 g of a cyclohexane solution containing 6.2 mg (0.032 mmol) of 2,2-di(2-tetrahydrofuranyl)propane, and 5 g of a cyclohexane solution containing 10 mg (0.16 mmol) of n-butyl lithium in purity were added at 50°C, and then 10 g of styrene and 40 g of 1,3-butadiene from which impurities had been removed were added to start polymerization. The temperature of the reaction solution rose due to the polymerization heat, and the maximum temperature reached 81°C. After the polymerization reaction was completed, 5 g of a cyclohexane solution containing 0.023 g of the copolymer C-2 obtained in Example 5 was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 50°C for 30 minutes to obtain a polymer solution.

[0467] Furthermore, 0.08 mmol of BTESPA was added and the reaction was allowed to proceed for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.

[0468] After adding 0.045 g of 2,6-di-tert-butyl-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the solution was vacuum dried to obtain a modified conjugated diene copolymer (copolymer C-3).

[0469] Comparative Example 1

[0470] In a nitrogen-substituted autoclave reactor, 200 g of cyclohexane, 5 g of a cyclohexane solution containing 6.2 mg (0.032 mmol) of 2,2-di(2-tetrahydrofuranyl)propane, and 5 g of a cyclohexane solution containing 10 mg (0.16 mmol) of n-butyl lithium in purity were added at 50°C, and then 10 g of styrene and 40 g of 1,3-butadiene from which impurities had been removed were added to start polymerization. The temperature of the reaction solution rose due to the polymerization heat, and the maximum temperature reached 81°C. After the polymerization reaction was completed, 5 g of a cyclohexane solution containing 0.021 g of the copolymer (C-1) obtained in Synthesis Example 3 was added to the reactor as a branching agent to carry out a branching reaction, and a modification reaction was carried out at a temperature of 50°C for 30 minutes to obtain a polymer solution.

[0471] Furthermore, 0.16 mmol of BTESPA was added and the modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.

[0472] After adding 0.045 g of 2,6-di-tert-butyl-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the solution was vacuum dried to obtain a modified conjugated diene copolymer (copolymer D-3).

[0473] Comparative Example 2

[0474] In a nitrogen-substituted autoclave reactor, 200 g of cyclohexane, 5 g of a cyclohexane solution containing 6.2 mg (0.032 mmol) of 2,2-di(2-tetrahydrofuranyl)propane, and 5 g of a cyclohexane solution containing 10 mg (0.16 mmol) of n-butyl lithium in purity were added at 50°C, and then 10 g of styrene and 40 g of 1,3-butadiene from which impurities had been removed were added to start polymerization. The temperature of the reaction solution rose due to the polymerization heat, and the maximum temperature reached 81°C. After the polymerization reaction was completed, 0.16 mmol of BTESPA was added to the reactor, and a modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.

[0475] After adding 0.045 g of 2,6-di-tert-butyl-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the solution was vacuum dried to obtain a modified conjugated diene copolymer E-3.

[0476] Tables 1 and 2 show the analysis results of the copolymers.

[0477] [Table 1]

[0478] Synthesis example 1 Synthesis example 2 Synthesis example 3 Vinyl aromatic copolymer A-1 B-1 C-1 Mn(g / mol) 941 1240 1430 Mw(g / mol) 2850 4980 5490 Mw / Mn(-) 3.03 4.02 3.83 Vinyl equivalent (g / eq.) 389 346 282 DVB content (wt%) 21.8 31.5 42.6 EVB content (wt%) 9.6 13.8 17.4 Styrene content (wt%) 44.6 33.6 22.2 Diisobutylene content (wt%) 24.0 21.1 17.8 Crosslinking degree (a1 / a) (%) 0.24 0.27 0.29 Residual vinyl fraction (a2 / (a+b)) (%) 0.144 0.206 0.280 <![CDATA[TGA 350 (wt%)]]> 1.41 1.32 1.28 Haze(-) 0.02 0.03 0.05 Example 1 Example 3 Example 5 Comparative Example 1 Modifier MPTMS MPTMS MPTMC one Modified vinyl aromatic copolymer A-2 B-2 C-2 C-3 Mn(g / mol) 4440 3630 3250 941 Mw(g / mol) 68300 54200 35600 2850 Mw / Mn(-) 15.4 14.9 11.0 3.03 DVB content (wt%) 14.5 20.1 25.1 21.8 EVB content (wt%) 6.4 8.8 10.3 9.6 Styrene content (wt%) 29.6 21.4 13.1 44.6 Diisobutylene content (wt%) 15.9 13.5 10.5 24.0 Modified group content (wt%) 33.5 36.2 41.1 0.0 Haze(-) 0.03 0.03 0.05 0.02

[0479] [Table 2]

[0480] Example 2 Example 4 Example 6 Comparative Example 1 Comparative Example 2 Modified vinyl aromatic copolymer A-2 B-2 C-2 A-1 one Modifier BTESPA BTESPA BTESPA BTESPA BTESPA Modified conjugated diene copolymer A-3 B-3 C-3 D-3 E-3 Mw(million) 48 49 51 31 27 Area of ​​multi-branch components (%) 58.5 51.5 49.5 7.3 Area above 3Mp (%) 32.1 27.3 33.7 3.1 Vinyl bonding amount (%) 39 36 38 46 48 Muni viscosity 62 61 65 51 47 Haze(-) 0.01 0.02 0.01 0.08 0.05

[0481] Example 7

[0482] The copolymer A-3 (copolymer rubber) obtained in Example 2, process oil, carbon black, zinc oxide, stearic acid and an antioxidant were mixed and kneaded at 155° C. and 60 rpm for 4 minutes using a Labo Plastomill.

[0483] Sulfur and a vulcanization accelerator were added to the kneaded product obtained by the kneading, and the mixture was kneaded at 70° C. and 60 rpm for 1 minute using a laboratory Plast mixer for vulcanization, thereby obtaining a crosslinked rubber A.

[0484] The blending ratios (parts by weight) are shown in Table 3. Table 4 also shows the physical properties of the crosslinked rubber A.

[0485] [Table 3]

[0486] Copolymer rubber 100.0 Process oil 37.5 Silicon dioxide 65.0 Carbon Black 5.0 Zinc Oxide 3.0 Stearic acid 1.0 Anti-aging agents 1.0 sulfur 1.8 Vulcanization accelerator 1.5

[0487] The additives used were as follows.

[0488] Process oil: Diana process oil AC-12 manufactured by Idemitsu Kosan

[0489] Silicon dioxide: Degussa, ULTRASIL VN3

[0490] Carbon black: Nitrotron #300 made by New Carbon

[0491] Zinc oxide: Zinc White No. 1 manufactured by Mitsui Mining and Smelting

[0492] Stearic acid: Made in NOF Corporation

[0493] Anti-aging agent: Nocceler-NS manufactured by Ouchi Shinko Chemical Industry

[0494] Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry

[0495] Vulcanization accelerator: N-tert-butylbenzothiazole-2-sulfenamide

[0496] Example 8-Example 9, Comparative Example 3-Comparative Example 4

[0497] Crosslinked rubbers B to F were obtained by the same method as in Example 7, except that the modified conjugated diene copolymer B-3, modified conjugated diene copolymer C-3, modified conjugated diene copolymer D-3 or modified conjugated diene copolymer E-3 synthesized in Example 4 and Example 6, or Comparative Examples 1 and 2 were used instead of the modified conjugated diene copolymer A-3.

[0498] Table 4 shows the types of the modified conjugated diene copolymer used and the physical properties of the cross-linked rubbers B to E obtained.

[0499] [Table 4]

[0500]

[0501] As shown in Table 4, the cross-linked rubber using the copolymer of the present invention provides equal or better dispersibility of silica and adhesion at the interface than when using divinylbenzene which is a known branching agent, and therefore the vulcanized rubber has excellent tensile strength and abrasion resistance.

[0502] Embodiment 11

[0503] 270 ml (210.3 g) of cyclohexane and 5 g of a cyclohexane solution containing 1.05 g (9.0 mmol) of N,N,N',N'-tetramethylethylenediamine were added, and 50 g of a cyclohexane solution containing 2.88 g (45.0 mmol) of n-butyllithium in purity was added at 50° C. Then, 4.73 g of DVB-630 (22.9 mmol of DVB and 13.4 mmol of EVB) from which impurities had been removed in advance and 27.96 g (269 mmol) of styrene were added to start polymerization. The temperature of the reaction solution rose due to the polymerization heat, and the maximum temperature reached 81° C. After the polymerization reaction was completed, 10.63 g (45.0 mmol) of 3-glycidoxypropyltrimethoxysilane (GPTMS) was added to the reactor as a modifier, and the modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified vinyl aromatic copolymer.

[0504] The obtained polymerization solution was devolatilized and concentrated to obtain 42.89 g (yield: 99.0 wt %) of a modified vinyl aromatic copolymer (copolymer A-11) in terms of solid content.

[0505] The Mn of copolymer A-11 is 4520, the Mw is 8870, and the Mw / Mn is 1.96. In addition, it contains 6.55 mol% (6.88wt%) of structural units derived from DVB, 3.79 mol% (4.04wt%) of structural units derived from EVB, 76.8 mol% (64.5wt%) of structural units derived from styrene, and 12.9 mol% (24.5wt%) of structural units derived from 3-glycidyloxypropyltrimethoxysilane. In addition, the crosslinking structural unit (a1) is 6.55 mol% (6.88wt%), and the crosslinking degree (a1 / a) is 1.00. In addition, the structural unit (a2) having residual vinyl groups is 0.0 mol%.

[0506] In addition, the weight loss at 350° C. was 1.25 wt %, and the haze value was 0.02.

[0507] Example 12

[0508] 270 ml (210.3 g) of cyclohexane and 5 g of a cyclohexane solution containing 1.05 g (9.0 mmol) of N,N,N',N'-tetramethylethylenediamine were added, and 50 g of a cyclohexane solution containing 2.88 g (45.0 mmol) of n-butyllithium in purity was added at 50°C. Then, 4.73 g of DVB-630 (22.9 mmol of divinylbenzene (mixture of meta-isomer and para-isomer) component and 13.4 mmol of ethylvinylbenzene (mixture of meta-isomer and para-isomer) component) from which impurities had been removed in advance and 27.96 g (269 mmol) of styrene were added to start polymerization. The temperature of the reaction solution rose due to the polymerization heat, and the maximum temperature reached 81°C. After the polymerization reaction was completed, 16.14 g (45.0 mmol) of triethoxysilyl thio propyl trimethoxy silane (TESTPTMS) was added to the reactor as a modifier and the modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified vinyl aromatic copolymer (copolymer B-11).

[0509] The obtained polymerization solution was devolatilized and concentrated to obtain 48.34 g (yield: 99.0 wt %) of a modified vinyl aromatic copolymer B-11 in terms of solid content.

[0510] The Mn of copolymer B-11 is 2190, the Mw is 3620, and the Mw / Mn is 1.65. In addition, it contains 6.56 mol% (6.10 wt%) of structural units derived from DVB, 3.78 mol% (3.58 wt%) of structural units derived from EVB, 76.8 mol% (57.3 wt%) of structural units derived from styrene, and 12.8 mol% (33.1 wt%) of structural units derived from 3-glycidyloxypropyltrimethoxysilane. In addition, the crosslinking structural unit (a1) is 6.55 mol% (6.09 wt%), and the degree of crosslinking is 1.00. In addition, the structural unit (a2) is 0.0 mol%.

[0511] The weight loss at 350° C. was 1.39 wt %, and the haze value was 0.03.

[0512] Table 5 shows the analysis results of the copolymers of Examples 11 and 12.

[0513] [Table 5]

[0514] Embodiment 11 Example 12 Synthesis Example 11 Modified vinyl aromatic copolymer A-11 B-11 C-11 Modifier GPTMS TESTPTMS one Mn(g / mol) 4520 2190 941 Mw(g / mol) 8870 3620 2850 Mw / Mn(-) 1.96 1.65 3.03 DVB content (wt%) 6.88 6.10 21.8 EVB content (wt%) 4.04 3.58 9.6 Styrene content (wt%) 64.5 57.3 44.6 Diisobutylene content (wt%) 24.0 Modified group content (wt%) 24.5 33.1 - Crosslinking degree (a1 / a) (%) 1.00 1.00 0.24 Residual vinyl fraction (a2 / (a+b)) (%) 0.00 0.00 0.14 <![CDATA[TGA 350 (wt%)]]> 1.25 1.39 1.41 Haze(-) 0.02 0.03 0.02

[0515] Example 13

[0516] In a nitrogen-substituted autoclave reactor, 200 g of cyclohexane and 5 g of a cyclohexane solution containing 6.2 mg (0.032 mmol) of 2,2-di(2-tetrahydrofuranyl)propane were charged, and 5 g of a cyclohexane solution containing 10 mg (0.16 mmol) of n-butyl lithium was added at 50°C, and then 10 g of styrene and 40 g of 1,3-butadiene from which impurities had been removed were added to start polymerization. The temperature of the reaction solution rose due to the polymerization heat, and the maximum temperature reached 81°C. After the polymerization reaction was completed, 5 g of a cyclohexane solution containing 0.076 g of the modified vinyl aromatic copolymer (A-11) obtained in Example 11 was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 50°C for 30 minutes to obtain a polymer solution.

[0517] Furthermore, 0.08 mmol of BTESPA was added and the reaction was allowed to proceed for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.

[0518] After adding 0.045 g of 2,6-di-tert-butyl-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the solution was vacuum dried to obtain a modified conjugated diene copolymer (copolymer A-12).

[0519] Embodiment 14

[0520] In a nitrogen-substituted autoclave reactor, 200 g of cyclohexane, 5 g of a cyclohexane solution containing 6.2 mg (0.032 mmol) of 2,2-di(2-tetrahydrofuranyl)propane, and 5 g of a cyclohexane solution containing 10 mg (0.16 mmol) of n-butyl lithium in purity were added at 50°C, and then 10 g of styrene and 40 g of 1,3-butadiene from which impurities had been removed were added to start polymerization. The temperature of the reaction solution rose due to the heat of polymerization, and the maximum temperature reached 81°C. After the polymerization reaction was completed, 5 g of a cyclohexane solution containing 0.085 g of the copolymer B-11 obtained in Example 12 was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 50°C for 30 minutes to obtain a polymer solution.

[0521] Furthermore, 0.08 mmol of BTESPA was added and the reaction was allowed to proceed for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.

[0522] After adding 0.045 g of 2,6-di-tert-butyl-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the solution was vacuum dried to obtain a modified conjugated diene copolymer (copolymer B-12).

[0523] Synthesis Example 11

[0524] 31.00 g of DVB-630 (0.150 mol of DVB, 0.088 mol of EVB), 65.72 g (0.631 mol) of styrene, 70.80 g (0.631 mol) of diisobutylene, 60 mmol (6.90 mL) of n-propyl acetate, and 48.55 g (0.527 mol) of toluene were placed in a 500 mL reactor, 15.2 mmol of boron trifluoride diethyl ether complex (1.91 mL) was added at 70° C., and the reaction was carried out for 2.0 hours. After the polymerization was stopped with a sodium bicarbonate aqueous solution, the oil layer was washed three times with pure water, and the copolymer was recovered under reduced pressure at 60° C. to obtain 60.6 g of a vinyl aromatic copolymer (copolymer C-11).

[0525] The obtained copolymer C-11 has an Mn of 941, an Mw of 2850, and an Mw / Mn of 3.03. In addition, it contains 19.0 mol% (21.8 wt%) of structural units derived from DVB, 8.3 mol% (9.6 wt%) of structural units derived from EVB, 48.6 mol% (44.6 wt%) of structural units derived from styrene, and 24.2 mol% (24.0 wt%) of structural units derived from diisobutylene. In addition, the crosslinked structural unit (a1) is 4.6 mol% (5.2 wt%), and the degree of crosslinking is 0.24. In addition, the structural unit (a2) is 14.4 mol% (16.5 wt%), and its molar fraction is 0.144.

[0526] The Tg of the cured product was 167° C., and the softening temperature was 280° C. or higher. The weight loss at 350° C. was 1.41 wt %. The haze value was 0.02.

[0527] Comparative Example 11

[0528] In a nitrogen-substituted autoclave reactor, 200 g of cyclohexane, 5 g of a cyclohexane solution containing 6.2 mg (0.032 mmol) of 2,2-di(2-tetrahydrofuranyl)propane, and 5 g of a cyclohexane solution containing 10 mg (0.16 mmol) of n-butyl lithium in purity were added at 50°C, and then 10 g of styrene and 40 g of 1,3-butadiene from which impurities had been removed were added to start polymerization. The temperature of the reaction solution rose due to the heat of polymerization, and the maximum temperature reached 81°C. After the polymerization reaction was completed, 5 g of a cyclohexane solution containing 0.021 g of the copolymer C-11 obtained in Synthesis Example 11 was added to the reactor as a branching agent to carry out a branching reaction, and a modification reaction was carried out at a temperature of 50°C for 30 minutes to obtain a polymer solution.

[0529] Furthermore, 0.16 mmol of BTESPA was added and the modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.

[0530] After adding 0.045 g of 2,6-di-tert-butyl-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the solution was vacuum dried to obtain a modified conjugated diene copolymer (copolymer C-12).

[0531] Comparative Example 12

[0532] In the same manner as in Comparative Example 2, a modified conjugated diene copolymer (copolymer D-12) was obtained.

[0533] Table 6 shows the analysis results of the obtained copolymer.

[0534] [Table 6]

[0535] Example 13 Embodiment 14 Comparative Example 11 Comparative Example 12 Modified vinyl aromatic copolymer A-11 B-11 C-11 - Modifier BTESPA BTESPA BTESPA BTESPA Modified conjugated diene copolymer A-12 B-12 C-12 D-12 Mw(million) 51 48 31 27 Area of ​​multi-branch components (%) 43.9 31.7 7.3 - Area above 3Mp (%) 26.7 11.2 3.1 - Vinyl bonding amount (%) 40 35 46 48 Muni viscosity 65 63 51 47 Haze(-) 0.02 0.03 0.08 0.05

[0536] Embodiment 15

[0537] The copolymer A-12 (copolymer rubber) obtained in Example 13, process oil, carbon black, zinc oxide, stearic acid and an antioxidant were mixed and kneaded at 155° C. and 60 rpm for 4 minutes using a laboratory Plasto mixer.

[0538] Sulfur and a vulcanization accelerator were added to the kneaded product obtained by the kneading, and the mixture was kneaded at 70° C. and 60 rpm for 1 minute using a laboratory Plast mixer for vulcanization, thereby obtaining a crosslinked rubber A.

[0539] The blending ratio and the additives used are the same as those in Example 7 and Table 3.

[0540] Example 16, Comparative Example 13-Comparative Example 14

[0541] Crosslinked rubbers B to D were obtained in the same manner as in Example 15 except that copolymer B-12, copolymer C-12 or copolymer D-12 obtained in Example 14 or Comparative Examples 11 and 12 was used instead of the modified conjugated diene copolymer A-12.

[0542] Table 7 shows the types of the modified conjugated diene-based copolymers used and the physical properties of the cross-linked rubbers B to D obtained.

[0543] [Table 7]

[0544]

[0545] Embodiment 17

[0546] 240 ml (186.96 g) of ethylcyclohexane and 2.31 g (12.0 mmol) of 2,2-di(2-tetrahydrofuryl)propane were placed in the reactor, and 37.5 g of a n-hexane solution containing 3.84 g (60.0 mmol) of n-butyl lithium was added at 50° C., and then 6.37 g of DVB-630 (30.0 mmol of DVB and 18.9 mmol of EVB) and 38.65 g (371.1 mmol) of styrene from which impurities had been removed were added to start polymerization. The temperature of the reaction solution rose due to the polymerization heat, and the maximum temperature reached 67° C. After the polymerization reaction was completed, 16.94 g (60.9 mmol) of 3-glycidoxy propyl triethoxy silane (GPTES) was added to the reactor as a modifier, and the modification reaction was carried out for 60 minutes to obtain a polymer solution containing a functional group-modified vinyl aromatic copolymer. The obtained polymerization solution was neutralized with succinic acid and then filtered.

[0547] The obtained polymerization solution was devolatilized and concentrated to obtain 61.34 g (yield: 99.0 wt %) of a functional group-modified vinyl aromatic copolymer (copolymer F-2) in terms of solid content.

[0548] Table 8 shows the analysis results of copolymer F-2.

[0549] Copolymer F-2 contains 6.24 mol% (6.30 wt%) of structural units derived from divinylbenzene, 3.73 mol% (3.98 wt%) of structural units derived from ethylvinylbenzene, 77.17 mol% (62.38 wt%) of structural units derived from styrene, and 12.66 mol% (27.34 wt%) of structural units derived from GPTES. The crosslinked structural unit (a1) is 6.05 mol% (6.11 wt%), and the degree of crosslinking (a1 / a) is 0.97. In addition, the structural unit (a2) derived from divinylbenzene having residual vinyl groups is 0.19 mol% (0.19 wt%), so the molar fraction of the structural unit (a2) relative to the total of the structural units (a) and the structural units (b) is 0.0021.

[0550] Embodiment 18

[0551] 240 ml (186.96 g) of ethylcyclohexane and 2.31 g (12.0 mmol) of 2,2-di(2-tetrahydrofuranyl)propane were added, and 37.5 g of a cyclohexane solution containing 3.84 g (60.0 mmol) of n-butyl lithium was added at 50°C, and then 8.92 g of DVB-630 (DVB 42.0 mmol, EVB 26.5 mmol) and 42.86 g (411.5 mmol) of styrene from which impurities had been removed were added to start polymerization. The temperature of the reaction solution rose due to the polymerization heat, and the maximum temperature reached 65°C. After the polymerization reaction was completed, 16.94 g (60.9 mmol) of GPTES was added to the reactor as a modifier, and the modification reaction was carried out for 60 minutes to obtain a polymer solution containing a functional group-modified vinyl aromatic copolymer. The obtained polymerization solution was neutralized with succinic acid and filtered.

[0552] The obtained polymerization solution was devolatilized and concentrated to obtain a modified vinyl aromatic copolymer (copolymer G-2) in an amount of 68.31 g (yield: 99.4 wt %) in terms of solid content.

[0553] Table 8 shows the analysis results of copolymer G-2.

[0554] Copolymer G-2 contains 7.77 mol% (7.96 wt%) of structural units derived from DVB, 4.90 mol% (5.02 wt%) of structural units derived from EVB, 76.09 mol% (62.37 wt%) of structural units derived from styrene, and 11.25 mol% (24.66 wt%) of structural units derived from GPTES. The cross-linked structural unit (a1) is 7.45 mol% (7.64 wt%), and the degree of cross-linking (a1 / a) is 0.96. In addition, the structural unit (a2) is 0.31 mol% (0.32 wt%), and the molar fraction of the structural unit (a2) relative to the total of the structural units (a) and (b) is 0.0035.

[0555] [Table 8]

[0556] Embodiment 17 Embodiment 18 Modified vinyl aromatic copolymer F-2 G-2 Modifier GPTES GPTES Mn(g / mol) 3650 3920 Mw(g / mol) 8300 13000 Mw / Mn(-) 2.27 3.31 DVB content (wt%) 6.30 7.96 EVB content (wt%) 3.98 5.02 Styrene content (wt%) 52.38 52.37 Modified group content (wt%) 27.34 24.66 Crosslinking degree (a1 / a) (%) 0.97 0.96 Residual vinyl fraction (a2 / (a+b)) (-) 0.0021 0.0035 <![CDATA[TGA 350 (wt%)]]> 1.34 1.06 Haze(-) 0.04 0.06

[0557] Embodiment 19

[0558] In a nitrogen-substituted autoclave reactor, 200 g of cyclohexane, 5 g of a cyclohexane solution containing 6.2 mg (0.032 mmol) of 2,2-di(2-tetrahydrofuranyl)propane, and 5 g of a cyclohexane solution containing 10 mg (0.16 mmol) of n-butyl lithium in purity were added at 50°C, and then 10 g of styrene and 40 g of 1,3-butadiene from which impurities had been removed were added to start polymerization. The temperature of the reaction solution rose due to the heat of polymerization, and the maximum temperature reached 76°C. After the polymerization reaction was completed, 5 g of a cyclohexane solution containing 0.081 g of the copolymer F-2 obtained in Example 17 was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 50°C for 60 minutes to obtain a polymer solution.

[0559] Furthermore, 0.08 mmol of BTESPABTESPA was added, and the reaction was allowed to proceed for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.

[0560] After adding 0.045 g of 2,6-di-tert-butyl-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the solution was vacuum dried to obtain a modified conjugated diene copolymer (copolymer F-3).

[0561] Embodiment 20

[0562] In a nitrogen-substituted autoclave reactor, 200 g of cyclohexane, 5 g of a cyclohexane solution containing 6.2 mg (0.032 mmol) of 2,2-di(2-tetrahydrofuranyl)propane, and 5 g of a cyclohexane solution containing 10 mg (0.16 mmol) of n-butyl lithium in purity were added at 50°C, and then 10 g of styrene and 40 g of 1,3-butadiene from which impurities had been removed were added to start polymerization. The temperature of the reaction solution rose due to the heat of polymerization, and the maximum temperature reached 77°C. After the polymerization reaction was completed, 5 g of a cyclohexane solution containing 0.090 g of the copolymer G-2 obtained in Example 18 was added to the reactor as a modifier to carry out a modification reaction, and the modification reaction was carried out at a temperature of 50°C for 60 minutes to obtain a polymer solution.

[0563] Furthermore, 0.08 mmol of bis(3-triethoxysilylpropyl)methylamine was added and the modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.

[0564] After adding 0.045 g of 2,6-di-tert-butyl-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the solution was vacuum dried to obtain a modified conjugated diene copolymer (copolymer G-3).

[0565] Table 9 shows the analysis results of the obtained copolymer.

[0566] [Table 9]

[0567] Embodiment 19 Embodiment 20 Modified vinyl aromatic copolymer F-2 G-2 Modifier BTESPA BTESPA Modified conjugated diene copolymer F-3 G-3 Mw(million) 49 47 Area of ​​multi-branch components (%) 41.2 38.6 Area above 3Mp (%) 28.2 24.6 Vinyl bonding amount (%) 32 27 Muni viscosity 67 65 Haze(-) 0.04 0.06

[0568] Example 21 to Example 22

[0569] Crosslinked rubbers F to G were obtained in the same manner as in Example 15 except that copolymer F-3 or copolymer G-3 was used.

[0570] Table 10 shows the types of the modified conjugated diene copolymer used and the physical properties of the obtained crosslinked rubbers F to G.

[0571] [Table 10]

[0572]

[0573] Industrial Applicability

[0574] The modified vinyl aromatic copolymer of the present invention can be used as the raw material of conjugated diene copolymer. Furthermore, the crosslinked rubber composition formed by crosslinking a filler in the conjugated diene copolymer can be effectively used as an elastomeric material such as a tire (particularly a tire tread), a shock-absorbing rubber, a rubber hose, a rubber roller, and a shoe material because of its excellent dispersibility of the filler. In addition, the polymer or the composition comprising it is effectively used as a molding material, a resin improver, a dielectric material, an insulating material, a heat-resistant material, a structural material, an optical material, etc.

Claims

1. A modified vinyl aromatic copolymer comprising a structural unit a derived from a divinyl aromatic compound and a structural unit b derived from a monovinyl aromatic compound, wherein at least a portion of the structural unit a is a cross-linked structural unit a1 as described below, Here, R 1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms, One or more ends of the modified vinyl aromatic copolymer are modified by a modifying group, wherein the modifying group comprises an alkoxysilyl group. The molar fraction of the crosslinking structural unit a1 relative to the structural unit a is in the range of 0.05 to 0.90, The modified vinyl aromatic copolymer has a number average molecular weight Mn of 500 to 100,000 in terms of standard polystyrene as measured by gel permeation chromatography, 50 g or more of which is dissolved in 100 g of a solvent selected from toluene, xylene, tetrahydrofuran, dichloroethane or chloroform, contains 0.5 mol% to 95.0 mol% of structural unit a and 5.0 mol% to 99.5 mol% of structural unit b relative to the total of structural unit a and structural unit b, and the content of structural units other than structural unit a and structural unit b is at most 50 mol%.

2. The modified vinyl aromatic copolymer according to claim 1, characterized in that: The copolymer contains one or more silane functional groups (c) represented by the following formula (c1) or formula (c2) on the side chain or at the terminal, Here, R 2 is a divalent alkylene group having 1 to 6 carbon atoms, R 3 , R 4 , R 5 , R 7 , R 8 and R 9 Each independently represents a methoxy group, an ethoxy group, a propoxy group, a butoxy group, an octyloxy group, a lauryl group, a phenoxy group, a benzyloxy group, a methyl group, an ethyl group, a propyl group, a butyl group, a cyclohexyl group, a phenyl group, or a benzyl group; wherein R 3 , R 4 and R 5 At least one of, or R 7 , R 8 and R 9 at least one of which is methoxy, ethoxy, propoxy, butoxy, octyloxy, lauryloxy, phenoxy, or benzyloxy, Each molecule has 1 to 20 silane functional groups (c), The number average molecular weight Mn is 500 to 100,000, and the molecular weight distribution Mw / Mn represented by the ratio of the weight average molecular weight Mw to the number average molecular weight Mn is 30.0 or less.

3. The modified vinyl aromatic copolymer according to claim 2, characterized in that: It includes one or more copolymers represented by any one of the following formulas (2) to (13), In the formula, R 2 is a divalent alkylene group having 1 to 6 carbon atoms, R 3 , R 4 and R 5 Each independently represents a methoxy group, an ethoxy group, a propoxy group, a butoxy group, an octyloxy group, a lauryl group, a phenoxy group, a benzyloxy group, a methyl group, an ethyl group, a propyl group, a butyl group, a cyclohexyl group, a phenyl group, or a benzyl group; wherein R 3 , R 4 and R 5 At least one of them is methoxy, ethoxy, propoxy, butoxy, octyloxy, lauryloxy, phenoxy, or benzyloxy; R 6 is an alkyl group having 1 to 6 carbon atoms, a vinyl group or hydrogen; the polymer is a copolymer chain; wherein the benzene ring in the formula can be any aromatic ring, In the formula, R 7 , R 8 and R 9 Each independently represents a methoxy group, an ethoxy group, a propoxy group, a butoxy group, an octyloxy group, a lauryl group, a phenoxy group, a benzyloxy group, a methyl group, an ethyl group, a propyl group, a butyl group, a cyclohexyl group, a phenyl group, or a benzyl group; wherein R 7 , R 8 and R 9 At least one of them is methoxy, ethoxy, propoxy, butoxy, octyloxy, lauryloxy, phenoxy, or benzyloxy; R 6 is an alkyl group having 1 to 6 carbon atoms, a vinyl group or hydrogen; and the polymer is a copolymer chain.

4. The modified vinyl aromatic copolymer according to claim 2 or 3, wherein the structural unit b derived from a monovinyl aromatic compound is a structural unit derived from one or more monomers selected from the group consisting of styrene, vinyl naphthalene, vinyl biphenyl, m-methylstyrene, p-methylstyrene, o-, p-dimethylstyrene, m-ethylvinylbenzene, indene and p-ethylvinylbenzene.

5. A method for producing a modified vinyl aromatic copolymer, comprising producing the modified vinyl aromatic copolymer according to any one of claims 2 to 4 from a multifunctional vinyl aromatic copolymer and a silane compound, wherein: The polyfunctional vinyl aromatic copolymer is a polyfunctional vinyl aromatic copolymer containing 0.5 mol% or more and 95.0 mol% or less of a structural unit a derived from a divinyl aromatic compound, 5.0 mol% or more and 99.5 mol% or less of a structural unit b derived from a monovinyl aromatic compound, and At least a part of the structural unit a is the crosslinking structural unit a1 and the following vinyl-containing structural unit a2, In the formula, R 1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms, The molar fraction of the crosslinking structural unit a1 relative to the structural unit a is in the range of 0.05 to 0.90, The molar fraction of the vinyl-containing structural unit a2 relative to the total of the structural unit a and the structural unit b is in the range of 0.001 to 0.80, Mn is 300 to 50,000, Mw / Mn is 20.0 or less, The silane compound is a silane compound represented by the following formula (15) and / or formula (16), In the formula, R 2 , R 3 , R 4 and R 5 Same as the above formula (c1), In the formula, R 6 , R 7 and R 8 R of the formula (c2) 7 , R 8 and R 9 same, The polyfunctional vinyl aromatic copolymer and the silane compound are dissolved in a hydrocarbon solvent and added at a temperature of 0° C. to 150° C. in the presence of a catalyst.

6. A modified conjugated diene copolymer, characterized in that: The modified vinyl aromatic copolymer (A) according to any one of claims 2 to 4 is reacted as a modifier with a polymer of a conjugated diene compound (B) having an active terminal, or a copolymer of a conjugated diene compound (B) having an active terminal and an aromatic vinyl compound (C).

7. The modified conjugated diene copolymer according to claim 6, comprising 0.001 wt% to 6 wt% of a structural unit A1 derived from a modified vinyl aromatic copolymer (A), 29 wt% to 99.999 wt% of a structural unit B1 derived from a conjugated diene compound (B), and 0 wt% to 70 wt% of a structural unit C1 derived from an aromatic vinyl compound (C).

8. The modified conjugated diene copolymer according to claim 6 or 7, wherein, in a differential molecular weight distribution curve obtained by gel permeation chromatography, when the total area is 100%, the area of ​​a region having a number average molecular weight Mn of at least three times the peak value on the lowest molecular weight side is at least 10%.

9. A modified conjugated diene copolymer composition, characterized in that: A filler or a reinforcing filler is blended into the modified conjugated diene-based copolymer according to any one of claims 6 to 8, wherein the reinforcing filler is at least one selected from the group consisting of a silica-based inorganic filler, a metal oxide, a metal hydroxide and carbon black. 10 . The modified conjugated diene-based copolymer composition according to claim 9 , further comprising a crosslinking agent.

11. A cross-linked rubber product, characterized in that: The modified conjugated diene copolymer composition according to claim 10 is cross-linked.

12. A tire component, characterized in that: Comprising the rubber cross-linked product as claimed in claim 11.

13. The modified vinyl aromatic copolymer according to claim 1, characterized in that: 95 mol% or more of the structural unit a is the cross-linked structural unit a1, and The modified vinyl aromatic copolymer has two or more terminals modified by a modifying group, wherein the modifying group has an alkoxysilyl group. The average number of functional groups per molecule is in the range of 2 to 20.

14. The modified vinyl aromatic copolymer according to claim 13, wherein The number average molecular weight Mn is 500 to 50,000, and the molecular weight distribution Mw / Mn is 10.0 or less.

15. The modified vinyl aromatic copolymer according to claim 14, wherein The number average molecular weight Mn is 900 to 10,000.

16. The modified vinyl aromatic copolymer according to any one of claims 13 to 15, wherein the monovinyl aromatic compound is one or more monomers selected from the group consisting of styrene, vinyl naphthalene, vinyl biphenyl, m-methylstyrene, p-methylstyrene, o-,p-dimethylstyrene, m-ethylvinylbenzene, indene and p-ethylvinylbenzene.

17. A method for producing a modified vinyl aromatic copolymer, wherein the modified vinyl aromatic copolymer is the modified vinyl aromatic copolymer according to any one of claims 13 to 16, and the method is characterized in that it comprises: a polymerization step, using an alkali metal compound or an alkaline earth metal compound as an anionic polymerization initiator to copolymerize a divinyl aromatic compound and a monovinyl aromatic compound, or a divinyl aromatic compound and a monovinyl aromatic compound with a monomer capable of anionic copolymerization with these compounds, to obtain a vinyl aromatic copolymer having a branched structure and active ends; and The terminal modification step is to react a compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group, or a precursor compound thereof, with the active terminal of the vinyl aromatic copolymer to form a functional group.

18. A modified conjugated diene copolymer, characterized in that: The modified vinyl aromatic copolymer according to any one of claims 13 to 16 is obtained by reacting a polymer of a conjugated diene compound or a copolymer of a conjugated diene compound and an aromatic vinyl compound.

19. The modified conjugated diene copolymer according to claim 18, comprising 0.001 wt% to 6 wt% of structural unit A1 derived from the modified vinyl aromatic copolymer, 29 wt% to 99.999 wt% of structural unit B1 derived from a conjugated diene compound, and 0 wt% to 70 wt% of structural unit C1 derived from an aromatic vinyl compound.

20. The modified conjugated diene copolymer according to claim 18 or 19, wherein in a differential molecular weight distribution curve obtained by gel permeation chromatography, when the total area is set to 100%, the area of ​​a region having a number average molecular weight Mn of 3 times or more of the peak value on the lowest molecular weight side is 10% or more.

21. A rubber composition, characterized in that: The modified conjugated diene-based copolymer according to any one of claims 18 to 20 contains 0.5 to 200 parts by weight of at least one reinforcing filler selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides and carbon black, based on 100 parts by weight of the modified conjugated diene-based copolymer.

22. The rubber composition according to claim 21, further comprising a crosslinking agent.

23. A cross-linked rubber product, characterized in that: The rubber composition according to claim 22 is cross-linked.

24. A tire component, characterized in that: Comprising the rubber cross-linked product as claimed in claim 23.

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