WO2023243644A1

WO2023243644A1 - Modified vinyl aromatic copolymer, method for producing same, modified conjugated diene copolymer obtained from same, resin composition, crosslinked resin and structural member

Info

Publication number: WO2023243644A1
Application number: PCT/JP2023/021983
Authority: WO
Inventors: 正直川辺; 格倉富
Original assignee: 日鉄ケミカル＆マテリアル株式会社
Priority date: 2022-06-15
Filing date: 2023-06-13
Publication date: 2023-12-21

Abstract

The present invention provides: a modified vinyl aromatic copolymer having reactivity and solubility which make the copolymer usable in the production of a copolymer rubber; and a copolymer rubber material which is obtained from the modified vinyl aromatic copolymer, and which exhibits processability, strength and homogeneity at the same time.　According to the present invention, structural units that are derived from a multifunctional vinyl aromatic compound (c) or an aromatic compound (d) that has 2 to 4 alkyl groups having 1 to 3 carbon atoms are contained in a polymer; and 50% by mole or more of the structural units derived from the component (c) or the component (d) are multifunctional structural units (e1) which are represented by formula (1) and have a group R1 that is derived from the aromatic structure of the component (c) or the component (d), and a group R2 or R3 that is derived from the component (c) or the component (d) excluding the aromatic structure. In the formula, R1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms; R2 represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms; R3 represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms; and n represents an integer of 1 to 3. Meanwhile, "Polymer" in the formula represents a main polymer structural unit that is derived from the component (a) or the component (b).　The present invention provides a modified vinyl aromatic copolymer which is characterized in that: an end of the above-described polymer is modified with at least one functional group that is selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group; the average number of functional groups per one molecule is 2.0 or more; and the number-average molecular weight Mn is 500 to 30,000.　

Description

Modified vinyl aromatic copolymer and method for producing the same, modified conjugated diene copolymer obtained therefrom, resin composition, crosslinked resin product, and structural member

The present invention relates to a modified vinyl aromatic copolymer, a method for producing the same, a modified conjugated diene copolymer having excellent processability, tensile strength and abrasion resistance, and a resin composition obtained therefrom. The present invention relates to a resin crosslinked product obtained by crosslinking the same, and a structural member.

A compound having a plurality of vinyl groups in its molecule tends to undergo intermolecular crosslinking reaction due to polymerization. Utilizing this property, such a compound can be added to a polymerization system and copolymerized to form a crosslinked product, thereby making the polymer insoluble or imparting functionality.
For example, divinylbenzene is an example of a compound that has multiple vinyl groups in its molecule, and by adding a small amount of this to a styrene polymerization system and copolymerizing it, and further introducing functional groups such as sulfonic acid groups, it can be used as an ion exchange resin. can be used. In addition, it is used as a crosslinking agent for styrene resins such as synthetic rubber, ABS resin, MBS resin, and unsaturated polyester resin, and as a modifier for polyethylene.
In addition, as another example, it is expected that functionality can be imparted to a thermoplastic resin by reacting a polyfunctional vinyl aromatic copolymer having a branched structure with a thermoplastic resin.
For example, conjugated diene rubbers such as SBR (styrene-butadiene rubber), BR (butadiene rubber), IR (isoprene rubber), and styrene-isoprene rubber have excellent abrasion resistance, elasticity, and water resistance, and can be used as molding materials and resins. It is used for various purposes such as a modifier.

One of the main uses of this conjugated diene rubber is automobile tires. Properties required for tires include mechanical strength, abrasion resistance, wet grip properties, etc. (hereinafter also referred to as strength etc.). Furthermore, in recent years, there has been active development of tires (so-called "eco-tires") that have excellent energy-saving performance, that is, low fuel consumption. In addition to strength, this eco-tire is required to have low rolling resistance.

It is known that fillers (reinforcing fillers) such as carbon black and silica are added to conjugated diene rubber to ensure tire strength. Terminal-modified solution polymerization type SBR (terminal-modified S-SBR) is attracting attention as a material that imparts resistance. Terminal-modified S-SBR has a functional group at the molecular end of SBR, and this functional group at the molecular end interacts with the filler. This interaction improves the dispersibility of the filler in SBR, and also restricts the molecular terminals of SBR and reduces its mobility. As a result, the tire's hysteresis loss (internal friction) is reduced and rolling resistance is reduced. Taking advantage of this characteristic, eco-tires that have both strength and low rolling resistance are being developed.

In such rubber compositions, in order to improve the affinity between the polymer used as the raw material rubber and the filler, for example, a method of modifying the butadiene-based polymer used as the raw material rubber by introducing a predetermined functional group into the butadiene-based polymer is used. Various methods are being considered.
For example, in Patent Document 1, a block copolymer consisting of an α-methylstyrene block and a butadiene block is synthesized by living anionic polymerization using an organolithium compound as an initiator in a nonpolar solvent, and if necessary, a polyfunctional Discloses reacting a coupling agent.
US Pat. No. 5,001,200 discloses star-block interpolymers having random copolymer blocks of conjugated dienes and monovinyl aromatic monomers, polyconjugated diene blocks, and functional groups derived from polyfunctional lithium-based initiators.
The techniques of Patent Documents 1 and 2 are considered to have the effect of ensuring the processability of rubber by introducing a branched structure into the rubber component. However, no special measures have been taken to interact with the filler to ensure strength, and the contribution to strength is not sufficient.
In Patent Document 3, a rubber composition in which a predetermined amount of carbon black is blended into a blended rubber containing a plurality of diene rubbers has a functional group that interacts with carbon black at the end of the molecular chain, and the diene rubber has a functional group that interacts with carbon black at the molecular chain end. Disclosed is a rubber composition containing a low molecular weight functional group-containing polymer having a polymer structure similar to that of a rubber component. However, since this technique involves blending a low molecular weight compound into the rubber, it does not contribute enough to the strength.
Patent Document 4 discloses crosslinked rubber particles containing a conjugated diene unit, an aromatic vinyl unit and a unit having at least two polymerizable unsaturated groups, and a conjugated diene/aromatic particle containing a conjugated diene unit having a specific bond structure. Rubber compositions containing vinyl copolymer rubber are disclosed. However, at least one functional group among carboxylic acid groups, amino groups, hydroxyl groups, epoxy groups, and alkoxysilyl groups introduced into the three-dimensionally crosslinked crosslinked rubber particles is inside the insoluble network structure of the crosslinked rubber particles. Some of the inorganic fillers get into the crosslinked rubber particles and cannot contribute to the dispersibility of the inorganic fillers outside the crosslinked rubber particles, so the effect of introducing functional groups was not sufficient.
Patent Document 5 describes a crosslinked polymer having a structural unit derived from an ethylenically unsaturated compound whose homopolymer has a glass transition temperature of 10° C. or higher and a structural unit derived from a crosslinkable compound, and a crosslinked polymer having a structural unit derived from a crosslinkable compound, and a crosslinked polymer having a structural unit derived from a crosslinkable compound. Disclosed is a conjugated diene rubber comprising an interpenetrating network structure polymer and a non-crosslinked polymer having structural units. However, since crosslinked polymers are three-dimensionally crosslinked polymers that are insoluble in solvents, they can also be used as interpenetrating network structure polymers with non-crosslinked polymers having structural units derived from conjugated diene compounds. Because the microgel is structurally fragile, the mechanical strength improvement effect was not sufficient.
Patent Document 6 discloses crosslinked polymer particles having polysiloxane on the particle surface and having an average particle diameter of 0.01 to 10 μm. However, polysiloxane-modified crosslinked polymer particles are solvent-insoluble crosslinked polymer particles that are hard and brittle, so they cannot be used to modify conjugated diene copolymers synthesized by anionic polymerization. , it was not possible to improve the strength.
U.S. Pat. No. 5,002,201 discloses reacting a divinylidene polymerization initiator with a monomer to form an "omega, omega'-carbanion" living polymer molecule, and combining at least one living polymer molecule and at least one equivalent of a chain end modifier. It is disclosed that modified polymer molecules can be obtained by reacting. However, when divinylbenzene is added as a coupling agent as a post-addition, microgels are formed, resulting in the problem that the strength improvement effect is not sufficient.
Patent Document 8 discloses that a polymer obtained by crosslinking aminomethylated polystyrene with 1% divinylbenzene is swollen with methylene chloride, and then reacted with tolylene 2,4-diisocyanate (TDI) to form silylated ferrocenyl. Crosslinked polymers containing diphosphine ligands are disclosed. However, it has been suggested that crosslinked polymers are not soluble in solvents, and branched polymers that are soluble in solvents could not be imagined.
Patent Document 9 describes an ethylene-styrene-divinylbenzene copolymer chain and a polystyrene chain obtained by anionic polymerization in the coexistence of an ethylene-styrene-divinylbenzene copolymer obtained by coordination polymerization and a styrene monomer. A modified resin composition is disclosed by blending an antioxidant, a silane coupling agent, and a radical initiator with a copolymer (cross copolymer) having the following properties and kneading the same. However, the divinylbenzene content of the cross copolymer is much less than 0.5 mol%, and there is no evidence that the silane coupling agent added afterward has modified the terminals of the cross copolymer. Furthermore, the possibility of improving the properties of conjugated diene polymers by coupling living conjugated diene polymers has not been suggested.

Therefore, in view of the above problems, the applicant has developed a specific polyfunctional vinyl aromatic copolymer, which has both a branched structure and an interaction function with fillers, as a constituent unit of a conjugated diene rubber to improve processability and strength. It is disclosed that a copolymer rubber having both high and homogeneous properties can be provided (Patent Document 10). Furthermore, Patent Documents 11 to 14 propose polyfunctional vinyl aromatic copolymers that essentially include indane structural units, structural units derived from cycloolefin compounds, and structural units derived from styrene.
The present invention contributes to the modification of resins by a method different from the methods disclosed in Patent Documents 10 to 14, and is particularly useful for rubber compositions such as tires, and improves properties such as strength and abrasion resistance. This project proposes materials that can contribute to improvements.

Japanese Patent Application Publication No. 2003-73434 Special Publication No. 2004-517202 Japanese Patent Application Publication No. 2005-213381 International Publication No. 2002/000779 Japanese Patent Application Publication No. 2013-155268 Japanese Patent Application Publication No. 7-207029 Special Publication No. 2016-530361 Japanese Patent Application Publication No. 8-259584 JP2012-92197A International Publication 2018/084128 Japanese Patent Application Publication No. 2004-123873 Japanese Patent Application Publication No. 2018-39995 International Publication 2018/181842 International Publication 2020/67336

The present invention solves the above problems and is a modified vinyl aromatic system having reactivity and solubility that can be used to produce a modified conjugated diene copolymer having a highly branched structure without producing a small amount of microgel as a by-product. The object of the present invention is to provide a copolymer, a resin composition having a branched structure that has processability, strength, and homogeneity, a resin crosslinked product obtained by crosslinking the same, and a structural member.

As a result of extensive studies, the present inventors found that the present invention contains a structural unit derived from a polyfunctional vinyl aromatic compound (c) or an aromatic compound having 2 to 4 alkyl groups having 1 to 3 carbon atoms (d). A polymer in which 50 mol% or more of the structural units derived from component (c) or component (d) is a polyfunctional structural unit (e1) represented by the following formula (1), which has a monovinyl aromatic The active end of the vinyl aromatic copolymer is composed of structural units derived from one or more monomers selected from the group consisting of compound (a) and conjugated diene compound (b). The present invention was completed based on the discovery that a copolymer modified with a group or a hydroxyl group can solve the above problems.

The present invention relates to a polymer comprising a structural unit derived from one or more monomers selected from the group consisting of a monovinyl aromatic compound (a) and a conjugated diene compound (b), wherein the polymer contains Contains a structural unit derived from a polyfunctional vinyl aromatic compound (c) or an aromatic compound (d) having 2 to 4 alkyl groups having 1 to 3 carbon atoms, and derived from component (c) or component (d) 50 mol% or more of the structural units are groups R1 derived from the aromatic structure of component (c) or (d), and groups R2 or It is a multifunctional structural unit (e1) represented by the following formula (1) having R3,

Here, R1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms, R2 represents hydrogen or a hydrocarbon group having 1 to 6 carbon atoms, and R3 represents hydrogen or a hydrocarbon group having 1 to 6 carbon atoms. n represents an integer from 1 to 3. Note that Polymer indicates the main polymer structural unit derived from component (a) or component (b).
Furthermore, the terminal of the polymer is modified with at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group, and the number average molecular weight is such that the average number of functional groups per molecule is 2.0 or more. This is a modified vinyl aromatic copolymer characterized by an Mn of 500 to 30,000.

In the modified vinyl aromatic copolymer, the polyfunctional structural unit (e1) represented by formula (1) is produced by the reaction of component (c) or component (d) with an organic alkali metal compound, It is preferable that R3 is a group partially containing a structure derived from an organic alkali metal compound or a hydrogen containing no structure.
The modified vinyl aromatic copolymer has 0.5 structural units derived from a polyfunctional vinyl aromatic compound (c) or an aromatic compound (d) having 2 to 4 alkyl groups having 1 to 3 carbon atoms. Contains 65.0 mol% or more and 35.0 mol% or less of structural units derived from one or more monomers selected from the group consisting of monovinyl aromatic compounds (a) and conjugated diene compounds (b). The content is preferably mol % or more and 99.5 mol % or less, and the molecular weight distribution (Mw/Mn) represented by the ratio of weight average molecular weight Mw to number average molecular weight Mn is preferably 10.0 or less. Further, the average number of the functional groups per molecule can be in the range of 2 to 20.
Examples of the monovinyl aromatic compound include styrene, vinylnaphthalene, vinylbiphenyl, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, m-ethylvinylbenzene, indene or p-ethylvinylbenzene.

The present invention also provides an alkali metal compound and one or more compounds selected from a polyfunctional vinyl aromatic compound (c) or an aromatic compound having 2 to 4 alkyl groups having 1 to 3 carbon atoms (d). an initiation reaction step of producing a polyfunctional anionic polymerization initiator by reacting; and polymerizing one or more monomers selected from the group consisting of a monovinyl aromatic compound (a) and a conjugated diene compound (b). , a polymerization step for obtaining a vinyl aromatic copolymer having a polyfunctional structural unit (e1) represented by the formula (1) and an active end; and an amino group at the active end of the vinyl aromatic copolymer. , an alkoxysilyl group, and a hydroxyl group, or a terminal modification step of reacting a compound having at least one functional group selected from the group consisting of an alkoxysilyl group and a hydroxyl group, or a precursor compound thereof to form a functional group. A method for producing a modified vinyl aromatic copolymer according to any one of Items 1 to 5.

Furthermore, the present invention provides a modified vinyl aromatic copolymer obtained by reacting a polymer of a conjugated diene compound or a copolymer of a conjugated diene compound and an aromatic vinyl compound with the modified vinyl aromatic copolymer described above. It is a conjugated diene copolymer.

The modified conjugated diene copolymer contains 0.001 to 6% by weight of the structural unit (A1) derived from the modified vinyl aromatic copolymer and 29 to 99% by weight of the structural unit (B1) derived from the conjugated diene compound. .999% by weight and 0 to 70% by weight of the structural unit (C1) derived from an aromatic vinyl compound. In the differential molecular weight distribution curve obtained by gel permeation chromatography (GPC) measurement, when the total area is taken as 100%, the number average molecular weight (Mn ) is preferably 20% or more.

In addition, the present invention provides that at least one reinforcing agent selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides, and carbon black is added to 100 parts by weight of the modified conjugated diene copolymer. This is a resin composition characterized by containing 0.5 to 200 parts by weight of a filler.

The resin composition can further contain a crosslinking agent. Further, the present invention is a crosslinked resin product characterized by being formed by crosslinking a resin composition further containing a crosslinking agent.
Moreover, the present invention is a structural member characterized by containing this resin crosslinked product.

The modified vinyl aromatic copolymer of the present invention can be used as a raw material for a modified conjugated diene copolymer. Furthermore, the crosslinked resin composition containing filler in this modified conjugated diene copolymer and crosslinking has excellent filler dispersibility, mechanical strength, and abrasion resistance, so it is suitable for tires (particularly tire treads). It is useful as an elastomer material for seismic isolation rubber, rubber hoses, rubber rollers, footwear materials, etc. It can also be applied to molding materials, resin modifiers, etc. Dielectric materials, insulating materials, heat-resistant materials, structural materials, adhesives, sealants, paints, coatings, sealants, printing inks, dispersions, etc. in the electrical/electronic industry, space/aircraft industry, architecture/construction industry, etc. It can be provided as an agent, etc.
Furthermore, films and sheets coated with the curable resin composition containing the modified vinyl aromatic copolymer of the present invention are suitably used in plastic optical parts, touch panels, flat displays, film liquid crystal devices, and the like. The modified vinyl aromatic copolymer of the present invention has properties such as heat resistance, dielectric properties, adhesion/adhesion, and optical properties of thermoplastic resins or curable resin compositions used as main materials for films, sheets, and prepregs. It can also be used as a modifier to modify the properties of. Furthermore, the curable resin composition containing the polyfunctional vinyl aromatic copolymer of the present invention as a main material can be processed into films, sheets, and prepregs for use. Furthermore, the curable resin composition containing the modified vinyl aromatic copolymer of the present invention can also be used as various optical elements such as optical waveguides and optical lenses.

A GPC chart showing a peak top molecular weight (Mp), a molecular weight twice Mp (2Mp), and a molecular weight three times Mp (3Mp) is shown.

The modified vinyl aromatic copolymer (hereinafter also referred to as a modified copolymer or copolymer) of the present invention is one selected from the group consisting of a monovinyl aromatic compound (a) and a conjugated diene compound (b). A polymer consisting of structural units derived from more than one type of monomer, which contains a polyfunctional vinyl aromatic compound (c) or an aromatic compound having 2 to 4 alkyl groups having 1 to 3 carbon atoms. Contains a structural unit derived from compound (d), and 50 mol% or more of the structural unit derived from compound (c) or compound (d) is derived from the aromatic structure of component (c) or component (d). It is a polyfunctional structural unit (e1) represented by the following formula (1) having a group R1 and a group R2 or R3 derived from a component other than the aromatic structure of the component (c) or the component (d),

Here, R1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms, R2 represents hydrogen or a hydrocarbon group having 1 to 6 carbon atoms, and R3 represents hydrogen or a hydrocarbon group having 1 to 6 carbon atoms. n represents an integer of 1 to 3. Note that Polymer indicates the main polymer structural unit derived from component (a) or component (b).
Furthermore, the terminal of the polymer is modified with at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group, and the number average molecular weight is such that the average number of functional groups per molecule is 2.0 or more. Mn is 500 to 30,000.

The modified vinyl aromatic copolymer of the present invention contains a structural unit derived from a polyfunctional vinyl aromatic compound (c) or an aromatic compound (d) having 2 to 4 alkyl groups having 1 to 3 carbon atoms. However, 50 mol% or more of the structural units derived from component (c) or (d) are represented by the above formula (1) produced by the reaction of component (c) or (d) with an organic alkali metal compound. This polyfunctional structural unit (e1) or (e2) plays an important role as a crosslinking component that branches the copolymer and makes it polyfunctional. When a conjugated diene compound polymer is modified using a polyfunctional modified vinyl aromatic copolymer, a high-molecular-weight, multi-branched component is produced, and the abrasion resistance can be improved.

Examples of the polyfunctional vinyl aromatic compound (c) preferably include diisopropenylbenzene, divinylbenzene, diisopropenylnaphthalene, divinylnaphthalene, diisopropenylbiphenyl, and divinylbiphenyl, but are not limited to these. isn't it. Each of the exemplified compounds may be an isomer such as an m-form or a p-form, or a mixture of these isomers.
Examples of aromatic compounds (d) having 2 to 4 alkyl groups having 1 to 3 carbon atoms include xylene, trimethylbenzene, diethylbenzene, triethylbenzene, dipropylbenzene, tripropylbenzene, dimethylnaphthalene, trimethylnaphthalene. , diethylnaphthalene, triethylnaphthalene, dipropylnaphthalene, tripropylnaphthalene, dimethylbiphenyl, trimethylbiphenyl, diethylbiphenyl, triethylbiphenyl, dipropylbiphenyl, and tripropylbiphenyl are preferably used, but are not limited to these. The exemplified compounds are isomers such as m-isomer and p-isomer or mixtures of these isomers in which the di-substituted compound is the m-substituted compound, and the tri-substituted compound is the 1,2,4-3-substituted compound, or the 1,3,5-substituted compound. It may be an isomer such as a -3-substituted product or a mixture of these isomers.
These (c) and (d) can be used alone or in combination of two or more. In other words, (c) and (d) may be combined. From the viewpoint of moldability, diisopropenylbenzene (m-form, p-form or a mixture of these isomers), divinylbenzene (m-form, p-form or a mixture of these isomers), xylene ( m-form, p-form or a mixture of these isomers), and diethylbenzene (m-form, p-form or a mixture of these isomers).

On the other hand, the monovinyl aromatic compound (a), which is a structural unit contained in the modified vinyl aromatic copolymer of the present invention, improves the solvent solubility, compatibility, and processability of the copolymer. Examples of monovinyl aromatic compounds include vinyl aromatic compounds such as styrene, vinylnaphthalene, vinylbiphenyl, α-methylstyrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, Nuclear alkyl-substituted vinyl aromatic compounds such as o-ethylvinylbenzene, m-ethylvinylbenzene, and p-ethylvinylbenzene; cyclic vinyl aromatic compounds such as indene, acenaphthylene, benzothiophene, and coumaron; There are no restrictions.
Styrene, ethylvinylbenzene, ethylvinylbiphenyl, ethylvinylnaphthalene, and indene, in particular, are used to prevent copolymers from gelling and to improve solvent solubility, compatibility, and processability due to their cost and availability. From this point of view, it is preferred and used. Each of the exemplified compounds may be an isomer such as an m-form or a p-form, or a mixture of these isomers.
From the viewpoint of compatibility and cost, styrene, ethylvinylbenzene (m-form, p-form or isomer mixture thereof), and p-methylstyrene are more preferred.

The conjugated diene compound (b), which is a structural unit contained in the modified vinyl aromatic copolymer of the present invention, 1) increases the introduction efficiency of the modifying group introduced into the modified vinyl aromatic copolymer, and 2) ) When reacting a modified vinyl aromatic copolymer with a polymer of a conjugated diene compound having an active end or a copolymer of a conjugated diene compound with an active end and an aromatic vinyl compound, the modified vinyl aromatic It has the function of increasing the reactivity of the terminal modified group of the system copolymer.

As the conjugated diene compound, a conjugated diene compound containing 4 to 12 carbon atoms per molecule is preferable, and a conjugated diene compound containing 4 to 8 carbon atoms is more preferable. Such conjugated diene compounds include, but are not limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1 , 3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene. Among these, 1,3-butadiene and isoprene are preferred from the viewpoint of ease of copolymerization reaction with aromatic vinyl compounds and ease of industrial availability. These may be used alone or in combination of two or more.

The modified vinyl aromatic copolymer of the present invention has a polymerization initiator having at least one functional group selected from the group consisting of an amino group (-NR), an alkoxysilyl group (Si-OR), and a hydroxyl group (-OH). The amount of the modifier introduced per molecule corresponds to the "average number of functional groups per molecule." The modified vinyl aromatic copolymer of the present invention has an average number of functional groups per molecule of 2.0 or more. If the value obtained by dividing the number average molecular weight of the copolymer by the functional group equivalent is 2.0 or more, it can be determined that two or more molecules are functionalized. The amount of the polymerization initiator or modifier having a functional group introduced is such that the average number of functional groups per molecule is preferably 2.0 to 20, more preferably 2.0 to 10.0, and even more preferably 2.0 to 10.0 at the terminal. The number is 0 to 6.0. Particularly preferred is the terminal number of 2.0 to 4.0.

The modified vinyl aromatic copolymer of the present invention can be produced, for example, by the following method.
That is, an organic alkali metal compound is reacted with one or more compounds selected from polyfunctional vinyl aromatic compounds (c) or aromatic compounds having 2 to 4 alkyl groups having 1 to 3 carbon atoms (d). an initiation reaction step of producing a polyfunctional anionic polymerization initiator; and polymerizing one or more monomers selected from the group consisting of a monovinyl aromatic compound (a) and a conjugated diene compound (b). A polymerization step for obtaining a vinyl aromatic copolymer having a polyfunctional structural unit (e1) represented by formula (1) and an active end, and an amino group, an alkoxy It can be produced by a method including a terminal modification step of reacting a compound having at least one functional group selected from the group consisting of a silyl group and a hydroxyl group, or a precursor compound thereof to form a functional group.

The modified vinyl aromatic copolymer of the present invention is derived from a polyfunctional vinyl aromatic compound (c), an aromatic compound having 2 to 4 alkyl groups having 1 to 3 carbon atoms (d), or a monovinyl aromatic compound. A copolymer containing a structural unit (a) derived from a conjugated diene compound and a structural unit (b) derived from a conjugated diene compound, but within a range that does not impair the effects of the structural units derived from components (a) to (d). In this method, compounds other than conjugated diene compounds and aromatic vinyl compounds (hereinafter also referred to as "other monomers") are used, and structural units derived from these other monomers (f) are copolymerized. Can be introduced during coalescence.

Specific examples of the above other monomer (f) preferably include acrylonitrile, methyl (meth)acrylate, ethyl (meth)acrylate, etc., but are not limited to these. isn't it. These can be used alone or in combination of two or more. Other monomers (f) may be used in an amount of less than 30 mol% of the total monomers. Thereby, the structural units derived from other monomers (f) are introduced within a range of less than 30 mol % based on the total amount of structural units in the copolymer. The content is preferably 10 mol% or less, more preferably 5 mol% or less.

In the method for producing a modified vinyl aromatic copolymer of the present invention, in the initiation reaction step, an alkali metal compound and a polyfunctional vinyl aromatic compound (c) or an alkyl group having 1 to 3 carbon atoms are combined with 2 to 3 carbon atoms. A polyfunctional anionic polymerization initiator is produced by reacting one or more compounds selected from the four aromatic compounds (d).

The structural unit of the polyfunctional anionic polymerization initiator produced in the above initiation reaction step becomes a polyfunctional structural unit (e1) represented by the following formula (1) through a polymerization step.

In formula (1), R1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms, R2 represents hydrogen or a hydrocarbon group having 1 to 6 carbon atoms, and R3 represents hydrogen or a hydrocarbon group having 1 to 6 carbon atoms. show. n represents an integer of 1 to 3. Note that Polymer indicates the main polymer structural unit derived from component (a) or component (b).
Here, 50 mol% or more of the structural units derived from component (c) or (d) are groups R1 derived from the aromatic structure of component (c) or (d), and component (c) or ( It is necessary that the polyfunctional structural unit (e1) represented by formula (1) has a group R2 or R3 derived from a component other than the aromatic structure of component d). Preferably it is 70 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol% or more. The proportion of polyfunctional structural units (e1) among the structural units derived from component (c) or component (d) is also referred to as the degree of polyfunctional structure.
In the modified vinyl aromatic copolymer of the present invention,
(c) Component: polyfunctional vinyl aromatic compound (c)
Component (d): aromatic compound (d) having 2 to 4 alkyl groups having 1 to 3 carbon atoms
Either or both of these are used as raw materials.
When component (c) is used as a raw material, R2 is hydrogen at the α-position of a vinyl group or a hydrocarbon group having 1 to 6 carbon atoms. For example, when butyl Li (C ₄ H ₉ Li) is used as the organic alkali metal compound of the initiator, active species are generated by the reaction between butyl Li and component (c), as shown in the reaction formula below. . Therefore, a pentyl group obtained by adding the carbon at the β-position of the vinyl group and the butyl group derived from butyl Li represents R3.

On the other hand, when component (d) is used, the reaction between component (d) and the organic alkali metal compound as an initiator becomes a chain transfer reaction as shown in the following reaction formula, for example, when butyl Li is used. . In this case, the remaining hydrogen after one hydrogen is extracted from the carbon becomes R3.

Among the structural units derived from component (c) or component (d), the proportion of the polyfunctional structural unit (e1) represented by formula (1) (degree of polyfunctional structure) can be controlled and changed as desired. As a parameter, if this ratio is less than 50 mol%, a large amount of modified vinyl aromatic copolymer with an average number of functional groups per molecule of 1.0 will be included, and the conjugated diene (co)polymer will be When this polymer is used for modification of coalescence, the branching reaction does not proceed sufficiently, so that the molecular weight does not increase sufficiently, and the effect of improving strength and abrasion resistance tends to be small.
The residual vinyl content (mol%) derived from component (c) in the modified vinyl aromatic copolymer is the residual vinyl group derived from component (c) relative to the total content of component (c). ) The content of the component is preferably 30 mol% or less, more preferably 20 mol% or less. It is particularly preferably at most 10 mol%, most preferably at most 5 mol%. By suppressing the residual vinyl content to 30 mol% or less, the amount of modifier introduced can be increased, so when this polymer is used to modify a conjugated diene (co)polymer, the molecular weight As the number of functional groups increases, the number of functional groups increases, which is preferable in order to achieve both filler dispersibility and abrasion resistance.

The organic alkali metal compound used in the initiation reaction step in the method for producing a modified vinyl aromatic copolymer of the present invention is not particularly limited, but, for example, an organic lithium compound is preferable. Specific examples of these include alkyllithium such as methyllithium, ethyllithium, n-propyllithium, n-butyllithium, sec-butyllithium, and t-butyllithium, phenyllithium, stilbenelithium, naphthyllithium, etc. .
The amount of the organic alkali metal compound to be used is based on the vinyl group of one or more compounds selected from polyfunctional vinyl aromatic compounds (c) or aromatic compounds having 2 to 4 alkyl groups having 1 to 3 carbon atoms (d). The amount is preferably 0.5 to 1.0 times the total amount of alkyl groups. More preferably, it is 0.7 to 1.0 times the mole. If the amount of the alkali metal compound used is less than 0.5 times the mole, when this polymer is used to modify a conjugated diene (co)polymer, the branching reaction will not proceed sufficiently and the molecular weight will not increase sufficiently. , there is a tendency that the improvement effect on strength and wear resistance becomes smaller. On the other hand, if the alkali metal compound is used in an amount exceeding 1.0 times the molar amount, a gel component tends to be generated when this polymer is used to modify a conjugated diene (co)polymer.
Obtained by reacting an alkali metal compound with one or more compounds selected from polyfunctional vinyl aromatic compounds (c) or aromatic compounds having 2 to 4 alkyl groups having 1 to 3 carbon atoms (d) The amount of the polyfunctional anionic polymerization initiator used is preferably 5.0 to 100 mmol per 100 g of monomer used for polymerization.
The initiation reaction step may be carried out using a mixture of an alkali metal compound and a compound having a functional group that interacts with silica. By carrying out the initiation reaction in the presence of the mixture, the polymerization initiation end of the modified vinyl aromatic copolymer of the present invention can be modified with a functional group that interacts with silica. In addition, in this specification, "the functional group which interacts with silica" means the group which has an element which interacts with silica, such as nitrogen, sulfur, phosphorus, and oxygen. "Interaction" refers to the formation of covalent bonds between molecules, or intermolecular forces weaker than covalent bonds (e.g., ion-dipole interactions, dipole-dipole interactions, hydrogen bonds, van der Waals It means the formation of electromagnetic forces (such as electromagnetic forces) that act between molecules.
Among the compounds having a functional group that interacts with silica and used for modifying the polymerization initiation terminal, nitrogen-containing compounds such as secondary amine compounds are preferred. Specific examples of the nitrogen-containing compound include dimethylamine, diethylamine, dipropylamine, dibutylamine, dodecamethyleneimine, N,N'-dimethyl-N'-trimethylsilyl-1,6-diaminohexane, piperidine, pyrrolidine, Hexamethyleneimine, heptamethyleneimine, dicyclohexylamine, N-methylbenzylamine, di-(2-ethylhexyl)amine, diallylamine, morpholine, N-(trimethylsilyl)piperazine, N-(tert-butyldimethylsilyl)piperazine, 1, Examples include 3-ditrimethylsilyl-1,3,5-triazinane.

In the initiation reaction step, a polar compound may be added. By adding a polar compound, it participates in the initiation reaction and growth reaction, and is also effective in controlling the molecular weight and molecular weight distribution and promoting the polymerization reaction.
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-oxolanyl)propane; Tertiary amine compounds such as methylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, quinuclidine; alkali metal alkoxides such as potassium-tert-amylate, potassium-tert-butyrate, sodium-tert-butyrate, sodium amylate, etc. Compounds include phosphine compounds such as triphenylphosphine. These polar compounds may be used alone or in combination of two or more.
The amount of the polar compound to be used is not particularly limited, and can be selected depending on the purpose and the like. Usually, the amount is preferably 0.01 to 100 mol per 1 mol of the alkali metal compound.

Copolymerization of a monomer containing a divinyl aromatic compound and a 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 are used. Specifically, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, and decalin; benzene, toluene, Examples include hydrocarbon solvents consisting of aromatic hydrocarbons such as xylene and mixtures thereof.
It is preferable that the above monomer and polymerization solvent are treated individually or as a mixture thereof with an organometallic compound. Thereby, monomers such as divinyl aromatic compounds and monovinyl aromatic compounds, and arenes and 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.

The polymerization temperature during copolymerization is not particularly limited as long as it is a temperature at which living anion polymerization proceeds, but from the viewpoint of productivity, it is preferably -20 ° C. to 150 ° C. In the terminal modification step after the completion of polymerization, From the viewpoint of ensuring a sufficient amount of reaction to the active end, the temperature is preferably -20°C to 120°C. More preferably it is 0°C to 100°C.

The mode of the above polymerization reaction is not particularly limited, but it can be carried out in a batch mode (also referred to as a "batch mode"), a continuous mode, or the like. In continuous mode, one or more connected reactors can be used. The reactor used is a tank type, tube type, etc. equipped with a stirrer. In the batch method, the molecular weight distribution of the obtained polymer is generally narrow, and Mw/Mn tends to be 1.0 or more and less than 3.0. Further, in a continuous type, the molecular weight distribution is generally wide, and Mw/Mn tends to be 1.5 or more and 10 or less.

In the production method of the present invention, the polyfunctional structural unit (e1) represented by the formula (1) produced by the reaction of component (c) or component (d) with an organic alkali metal compound in the polymerization step and an active terminal. After obtaining the vinyl aromatic copolymer, a compound (including a precursor) having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group is added to the active terminal of the vinyl aromatic copolymer. A functional group is introduced into the terminal end of the modified vinyl aromatic copolymer of the present invention by reacting with (also referred to as).
The modifier reacts with the active end of the copolymer, and in the present invention binds to the active end derived from the conjugated diene compound (b). The content of the modifier bonded to the active end derived from the conjugated diene compound (b) is 50 mol% or more, which increases the molecular weight of the modified conjugated diene copolymer and improves its wear resistance when used as an automobile tire. It is preferable to improve the performance. Preferably it is 70 mol% or more, more preferably 80 mol% or more, still more preferably 85 mol% or more, particularly preferably 90 mol% or more.

The reaction temperature, reaction time, etc. when reacting a compound having a functional group at the active end (including a precursor) are not particularly limited, but it is preferable to react at -20°C to 120°C for 30 seconds or more. .
The amount of the modifier having a functional group to be added is not particularly limited, but in the initiation reaction step, the alkali metal compound and the polyfunctional vinyl aromatic compound (c) or the alkyl group having 1 to 3 carbon atoms are combined with 2 to 4 The sum of the modifiers having functional groups relative to the equivalent number of active species induced by the polyfunctional anionic polymerization initiator obtained by reacting one or more compounds selected from the aromatic compounds (d) The number of moles is preferably in a range of 0.3 to 6 times. The lower limit is more preferably 0.5, still more preferably 0.7, particularly preferably 0.9. On the other hand, a more preferable upper limit is 3 times, still more preferably 2 times, and particularly preferably 1.5 times. If the amount added is 0.3 times or more, it is preferable from the viewpoint of obtaining a sufficient modification rate in the target modified vinyl aromatic copolymer.

When the polymerization process is a batch process, the terminal modification step may be carried out in the same reactor used in the polymerization step, or may be carried out by being transferred to the next reactor. If the polymerization process is continuous, it is carried out by transferring to the next reactor. The terminal modification step is preferably carried out immediately following the polymerization step, and preferably within 5 minutes, the modifier is mixed and the reaction is carried out. The reactor for the modification reaction is preferably one that allows sufficient stirring. Specifically, there are static mixer type reactors, stirrer-equipped tank type reactors, and the like.

The terminal modification step is a step in which the active end of the vinyl aromatic copolymer is reacted with a modifier having at least one functional group selected from an amino group, an alkoxysilyl group, and a hydroxyl group. The modifier must have an amino group, an alkoxysilyl group, or a hydroxyl group as a functional group, and other functional groups, such as a halogen group, a ketone group, an ester group, an amide group, and an epoxy group, must be used as a functional group. It may have a group.

The modifier having an amino group is not particularly limited, but specifically includes a compound having an amino group and a functional group bonding to the active end of the polymer in the molecule, and preferably having no active hydrogen. The amino group is not particularly limited, but specifically, a functional group inert to alkali metals is preferable, such as a di-substituted amino group, i.e., a tertiary amine, a protected mono-substituted amino group, or a group containing two hydrogen atoms. A protected amino group is preferred. Examples of protected monosubstituted amino groups or amino groups in which two hydrogens are protected include one hydrogen of a monosubstituted amino group or two hydrogens of an amino group each substituted with a trialkylsilyl group. The following can be mentioned.

The modifier having an alkoxysilyl group is not particularly limited, but specifically, a compound having a plurality of alkoxysilyl groups in the molecule (this includes a compound having a silyl group to which a plurality of alkoxy groups are bonded) and compounds having an alkoxysilyl group and a functional group bonding to the polymer active end in the molecule. Note that these are preferably compounds that do not have active hydrogen.

Modifiers that form hydroxyl groups are not particularly limited, but specifically include compounds that have a functional group that binds to the active end of the polymer and that generates a hydroxyl group after the bonding reaction; Examples include compounds that have a functional group that does not bond and that later generates a hydroxyl group through a reaction such as hydrolysis, and are preferably compounds that do not have active hydrogen.
Examples of the compound having a functional group that produces a hydroxyl group after the bonding reaction include compounds having a ketone group, an ester group, an amide group, an epoxy group, and the like. Moreover, examples of compounds having a functional group that generates a hydroxyl group through a reaction such as hydrolysis after a bonding reaction include compounds having an alkoxysilyl group, an aminosilyl group, and the like.

Specific examples of the modifier are shown below. The compound that binds to the active end of the polymer to form an amino group at the end of the polymer is not particularly limited, but examples include C=N double bond compounds such as N,N'-dicyclohexylcarbodiimide.
The compound that binds 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 N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone ( Ketone compounds having an amino group such as Michler's ketone), N,N,N',N'-tetraethyl-4,4'-diaminobenzophenone; cyclic urea compounds such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone Cyclic amides, ie, lactam compounds; Amino group-containing epoxy compounds such as N,N,N',N'-tetraglycidyl-1,3-bisaminomethylcyclohexane; Nitrogen-containing heterocyclics described in JP-A No. 2001-131227 Examples include epoxy compounds having groups.
Compounds that combine with the active end of the polymer to form an alkoxysilyl group at the end of the polymer include, but are not particularly limited to, halogenated alkoxysilane compounds such as trimethoxychlorosilane, triethoxychlorosilane, and diphenoxydicrylorosilane. ; Examples include polyfunctional alkoxysilane compounds such as bis(trimethoxysilyl)ethane and bis(3-triethoxysilylpropyl)ethane.
Compounds that combine with the active end of the polymer to form an alkoxysilyl group and a hydroxyl group at the end of the polymer include, but are not particularly limited to, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane epoxy Examples include polysiloxane compounds having a group and an alkoxysilyl group in the molecule.

Compounds that combine with the active end of the polymer to form an amino group and an alkoxysilyl group at the end of the polymer include, but are not particularly limited to, 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropyldimethoxymethylsilane, 3-dimethylaminopropyldimethoxymethylsilane, -Alkoxysilane compounds to which an alkyl group having an amino substituent is bonded, such as dimethylaminopropyltriethoxysilane, bis(3-trimethoxysilylpropyl)methylamine, bis(3-triethoxysilylpropyl)methylamine; N-[ WO2007/3-(triethoxysilyl)-propyl]-N,N'-diethyl-N'-trimethylsilyl-ethane-1,2-diamine, 3-(4-trimethylsilyl-1-piperazinyl)propyltriethoxysilane, etc. Alkoxysilane compound to which a protected monosubstituted amino group is bonded as described in No. 034785; N-[2-(trimethoxysilanyl)-ethyl]-N,N',N'-trimethylethane-1,2-diamine , 1-[3-(triethoxysilanyl)-propyl]-4-methylpiperazine, 2-(trimethoxysilanyl)-1,3-dimethylimidazolidine, bis-(3-dimethylaminopropyl)-dimethoxysilane Alkoxysilane compounds with multiple substituted amino groups bonded as described in WO2008/013090 such as 1,4-bis[3-(trimethoxysilyl)propyl]piperazine, 1,4-bis[3-(triethoxysilyl) Alkoxysilane compounds bonded with nitrogen-containing heterocycles described in WO2011/040312 such as [propyl]piperazine; 3-[N,N-bis(trimethylsilyl)amino]propyltrimethoxysilane, ) amino] propylmethyldiethoxysilane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilyl Examples include alkoxysilane compounds bonded with azasilane groups described in WO2011/129425 such as propyl)-1-aza-2-silacyclopentane.
The compound that binds to the active end of the polymer to form a hydroxyl group at the end of the polymer is not particularly limited, but examples thereof include epoxy compounds such as ethylene oxide and propylene oxide; ketone compounds such as benzophenone.

The modified vinyl aromatic copolymer of the present invention obtained by the above production method is modified with at least one reactive functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group. Therefore, although it may be molded and cured alone, it is preferable to use other polymerizable resins for functional group modification and synthesis of high molecular weight multibranched components. In particular, the modified vinyl aromatic copolymer of the present invention can be used to obtain a conjugated diene copolymer (rubber) obtained by copolymerizing a conjugated diene compound alone and/or a conjugated diene compound and other monomers. , used for functional group modification and synthesis of high molecular weight hyperbranched components.
In the modified vinyl aromatic copolymer of the present invention, when component (c) or component (d) is reacted with an organic alkali metal compound when starting the reaction, component (c) or component (d) is A multi-branched component that reacts with the organic alkali metal compound and serves as the origin of multiple branched chains is generated. The proportion of the multibranched component derived from component (c) or component (d) is defined as the degree of polyfunctional structure derived from the initiator, and is expressed as a molar fraction with respect to the total amount of component (c) or component (d) in the raw material. The degree of polyfunctional structure derived from the initiator is preferably 0.50 or more, more preferably 0.70 or more. More preferably, it is 0.80 or more, particularly preferably 0.90 or more. By setting the degree of polyfunctional structure derived from the initiator to 0.50 or more, the amount of modifier introduced can be increased, so when this polymer is used to modify a conjugated diene (co)polymer, the dispersion of the filler is This is preferable because it has both properties and abrasion resistance.

The modified copolymer of the present invention is excellent as a modifier for conjugated diene (co)polymers (rubbers). Although the detailed mechanism is unknown, by introducing an appropriate amount of functional groups into the modified copolymer of the present invention, the rubber is modified, resulting in a modified conjugated diene copolymer (modified rubber). It is presumed that this tends to concentrate near the reinforcing filler, increasing the reinforcing effect of the reinforcing filler, and leading to improvement in the abrasion resistance of the resulting crosslinked product.
Furthermore, by using the modified rubber, the affinity between the modified conjugated diene copolymer of the present invention and the reinforcing filler is improved, and the dispersion state of each component such as the reinforcing filler in the resin composition is improved. It is estimated that this will be ideal for improving the physical properties of the crosslinked product (for example, improving abrasion resistance, improving handling stability, dry grip performance, and wet grip performance).
On the other hand, if the number of functional groups in the modified conjugated diene copolymer becomes too large, the reinforcing filler will aggregate due to the interaction between the copolymers adsorbed on the reinforcing filler, and this copolymer will aggregate. It is presumed that the coalescence does not contribute to improving the affinity between the modified conjugated diene copolymer and the reinforcing filler.

The average number of functional groups per molecule of the modified vinyl aromatic copolymer is determined by the following formula from the functional group equivalent (g/eq) of the modified vinyl aromatic copolymer (A) and the number average molecular weight Mn in terms of styrene. It can be obtained by (1).
Average number of functional groups per molecule = [(number average molecular weight Mn)/(average molecular weight of divinyl aromatic compound unit and monovinyl aromatic compound)]/(equivalent of functional group) (1)
Note that the equivalent weight of the functional group of the modified vinyl aromatic copolymer (A) means the mass of the divinyl aromatic compound unit and monovinyl aromatic compound bonded per functional group. The equivalent weight of the functional group can be calculated from the area ratio of the peak derived from the functional group and the peak derived from the polymer main chain using ¹ H-NMR or ¹³ C-NMR.

The average number of functional groups per molecule in the modified vinyl aromatic copolymer (A) is preferably 2 to 20. More preferably, the number is 2 to 10. Particularly preferably 2 to 5 pieces. If the average number of functional groups per molecule exceeds 20, the viscosity increases when the reinforcing filler (D) is dispersed, processability deteriorates, and the wear resistance of the resulting crosslinked product tends to decrease. be. When the average number of functional groups per molecule is lower than 2, the dispersibility effect of the reinforcing filler (D) is poor, and it is difficult to improve the physical properties of the crosslinked product in which the reinforcing filler (D) can be dispersed. This tends to be less than ideal. The amount of the modifier added into the modified vinyl aromatic copolymer (A) having at least one functional group selected from an amino group, an alkoxysilyl group, and a hydroxyl group can be determined by, for example, nuclear magnetic resonance spectroscopy. It can be determined using various analytical instruments such as methods.

The modified vinyl aromatic copolymer of the present invention has 0.0.5 structural units derived from a polyfunctional vinyl aromatic compound (c) and an aromatic compound (d) having 2 to 4 alkyl groups having 1 to 3 carbon atoms. Contains 5 to 35.0 mol%.
When the structural unit consists only of structural units derived from (a), (b), (c) and (d), the polyfunctional vinyl aromatic compound (c) and an alkyl group having 1 to 3 carbon atoms are The number of structural units derived from the aromatic compound (d), which has four, is 0.005 to 0.35 relative to the total of the structural units derived from (a), (b), (c), and (d). This molar fraction is calculated using the following formula (2).
[(c)+(d)]/[(a)+(b)+(c)+(d)] (2)
(Here, (a): molar fraction of structural units derived from monovinyl aromatic compound (a), (b): structural units derived from conjugated diene compound (b), (c): divinyl aromatic compound ( The mole fraction of the structural unit derived from c) and the mole fraction of the structural unit derived from the aromatic compound (d) having 2 to 4 alkyl groups having 1 to 3 carbon atoms.)
The lower limit of the above mole fraction is preferably 0.006, more preferably 0.007. Moreover, a preferable upper limit is 0.35, more preferably 0.30. Optimally, it is between 0.01 and 0.25.
In addition, when containing structural units other than those derived from (a), (b), (c) and (d), the lower limit of the preferable content is 0.2 mol%, more preferably 0.4 mol%. and more preferably 0.6 mol%. Moreover, a preferable upper limit is 35 mol%, more preferably 30 mol%, and still more preferably 25 mol%.

The modified vinyl aromatic copolymer of the present invention has 65.0 to 99 structural units derived from one or more monomers selected from the group consisting of monovinyl aromatic compounds (a) and conjugated diene compounds (b). Contains .5 mol%. In terms of mole fraction, it is 0.65 to 0.995. A preferable lower limit is 0.70. A more preferable lower limit is 0.75. Further, a preferable upper limit is 0.994, more preferably 0.993. Optimally, it is between 0.75 and 0.99.

The molar fraction of structural units derived from one or more monomers selected from the group consisting of monovinyl aromatic compounds (a) and conjugated diene compounds (b) is the structural units (a), (b), (c ) and (d), it is calculated using the following formula (3).
[(a)+(b)]/[(a)+(b)+(c)+(d)] (3)
(Here, (a), (b), (c) and (d) are synonymous with formula (3).)
In addition, even when structural units other than the structural units derived from (a), (b), (c) and (d) are included, the preferable molar fraction of the structural units derived from (a) and (b) is as described above. is within the range of

The modified vinyl aromatic copolymer of the present invention can contain other structural units in addition to the above structural units. Details of other structural units can be understood from the description of the manufacturing method.

The Mn (number average molecular weight measured using gel permeation chromatography in terms of standard polystyrene) of the modified vinyl aromatic copolymer of the present invention is 500 to 30,000. A preferable lower limit is 600, more preferably 700, still more preferably 800, particularly preferably 900. On the other hand, a preferable upper limit is 25,000, more preferably 20,000, still more preferably 15,000, and particularly preferably 10,000. When Mn is less than 500, the amount of functional groups contained in the copolymer decreases, so the reactivity with the active end of the conjugated diene copolymer tends to decrease, and when it exceeds 30,000, In addition to becoming more likely to generate gel, moldability and tensile elongation at break tend to decrease. The upper limit of the molecular weight distribution (Mw/Mn) is preferably 10.0 or less, more preferably 5.0 or less. Particularly preferred is 3.0. When Mw/Mn exceeds 10.0, the processing characteristics of the copolymer rubber tend to deteriorate and gels tend to occur.

The modified vinyl aromatic copolymer of the present invention is soluble in a solvent selected from toluene, xylene, tetrahydrofuran, dichloroethane or chloroform, but advantageously any of the abovementioned solvents. It is preferable that 50 g or more of the solvent is dissolved in 100 g of these solvents. More preferably, it dissolves 80 g or more.

The obtained modified vinyl aromatic copolymer of the present invention has at least one reactive functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group, so it can be molded and cured alone. However, it is preferable to use other polymerizable resins for functional group modification and synthesis of high molecular weight, multi-branched components. In particular, the modified vinyl aromatic copolymer of the present invention can be used to obtain a conjugated diene copolymer (rubber) obtained by copolymerizing a conjugated diene compound alone and/or a conjugated diene compound and other monomers. , used for functional group modification and synthesis of high molecular weight hyperbranched components.

By copolymerizing the polyfunctional 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 (A) based on the modified vinyl aromatic copolymer of the present invention is obtained. When aromatic vinyl compound (C) is not used, modified diene rubber such as butadiene rubber or isoprene rubber can be obtained, and by using aromatic vinyl compound (C), modified diene rubber such as modified SBR can be obtained. A conjugated diene copolymer can be obtained. These modified conjugated diene copolymers exhibit rubber properties and are therefore also referred to as modified copolymer rubbers.

The polymerization step for obtaining the modified conjugated diene copolymer of the present invention involves polymerizing the conjugated diene compound (B) using an alkali metal compound or alkaline earth metal compound as a polymerization initiator, or polymerizing the conjugated diene compound (B) and A polymerization step of copolymerizing an aromatic vinyl compound (C) to obtain a conjugated diene copolymer having an active end, and a branched polymer-type modified group (A) based on the modified vinyl aromatic copolymer. ).)

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

Examples of the aromatic vinyl compound (C) include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, vinylxylene, 4-cyclohexylstyrene, 2,4,6-trimethylstyrene, tert- Butoxydimethylsilylstyrene, isopropoxydimethylsilylstyrene, and the like can be used alone or in combination of two or more, and among these, styrene is particularly preferred.

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. Furthermore, when styrene is not used as the aromatic vinyl compound and 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 these, those having a styrene-butadiene rubber (SBR) structure are particularly preferred because they have excellent wear resistance, heat resistance, and aging resistance.

In the method for producing a modified conjugated diene copolymer of the present invention, the polymerization step and terminal modification step can be performed in the same manner as the polymerization step and terminal modification step of the modified vinyl aromatic copolymer described above. As the polymerization initiator used in the polymerization step and the compound having a functional group used in the terminal modification step, the above-mentioned polymerization initiators and compounds having a functional group can be used.

This polymerization or copolymerization of the conjugated diene compound (B) 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 are used. Specifically, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, and decalin; benzene, toluene, Examples include hydrocarbon solvents consisting of aromatic hydrocarbons such as xylene and mixtures thereof.
It is preferable that the above-mentioned conjugated diene compound and polymerization solvent are treated alone or as a mixture thereof with an organometallic compound. Thereby, arenes and acetylenes contained in the conjugated diene compound and 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.

The polymerization temperature when copolymerizing the conjugated diene compound (B) or the conjugated diene compound (B) and the aromatic vinyl compound (C) is not particularly limited as long as it is a temperature at which living anion polymerization proceeds, but productivity From the viewpoint of 0° C. or higher, the temperature is preferably 0° C. or higher, and the structural unit (c ) The temperature is preferably 120° C. or lower from the viewpoint of ensuring a sufficient reaction amount of the modified vinyl aromatic copolymer having the following. More preferably it is 50 to 100°C.
The polymerization mode when copolymerizing the conjugated diene compound (B) or the conjugated diene compound (B) and the aromatic vinyl compound (C) is not particularly limited, but may be a batch method (also referred to as a "batch method"). The polymerization can be carried out in a continuous polymerization mode. In continuous mode, one or more connected reactors can be used. The reactor used is a tank type, tube type, etc. equipped with a stirrer. In the batch method, the molecular weight distribution of the obtained polymer is generally narrow, and Mw/Mn tends to be 1.0 or more and less than 1.8. Further, in a continuous type, the molecular weight distribution is generally wide, and Mw/Mn tends to be 1.8 or more and 3 or less.

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, more preferably 150,000 to 1,000,000 in consideration of processability and physical properties. The weight average molecular weight can be determined by measuring a chromatogram using GPC using a column using polystyrene gel as a packing material, and using a calibration curve using standard polystyrene.
In the differential molecular weight distribution curve obtained by gel permeation chromatography (GPC) measurement, when the total area is taken as 100%, the number average molecular weight (Mn) is three times or more (3 Mp or more) of the lowest molecular weight peak. It is preferable that the area of the region is 20% or more. More preferably, it is 40 area % or more. Particularly preferably, it is 60 area % or more.

The modified conjugated diene copolymer of the present invention contains 0.001 to 6% by weight of the structural unit (A1) derived from the modified vinyl aromatic copolymer and 29% by weight of the structural unit (B1) derived from the conjugated diene compound. It is preferable to contain the structural unit (C1) derived from an aromatic vinyl compound in an amount of 0 to 70% by weight.
The structural unit (A1) derived from the modified vinyl aromatic copolymer (A) is preferably 0.001 to 5% by weight, more preferably 0.005 to 5% by weight, even more preferably 0.01 to 5% by weight. % by weight, optimally from 0.001 to 1% by weight. 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 Preferably it is 95 to 99.99% by weight.
When using the aromatic vinyl compound (C), the structural unit (A1) is in the same range as above, and the structural unit (B1) is 30 to 97.999% by weight, preferably 45 to 94.995% by weight. %, more preferably 55 to 89.99% by weight. The structural unit (C1) derived from the aromatic vinyl compound (C) is 2 to 50% by weight, preferably 5 to 45% by weight, and more preferably 10 to 40% by weight.

The microstructure (cis, trans, vinyl bond content) of the modified conjugated diene copolymer can be changed arbitrarily by using polar compounds, etc., but before the terminal is modified, the amount of conjugated diene units The content of vinyl bonds (1,2-bonds) is preferably 10 to 80 mol%. When the modified conjugated diene copolymer of the present invention is used as a resin composition as described below and further crosslinked to form an automobile tire, in order to achieve a high balance between rolling resistance performance and abrasion resistance, The amount is preferably mol%, more preferably 25 to 75 mol%, and even more preferably 25 to 70 mol%. Optimally, it is between 25 and 45 mol%. At this time, the mass ratio of cis bonds to trans bonds in the conjugated diene bond unit is preferably cis bonds/trans bonds=1/1.1 to 1.5.

If necessary, a reaction terminator may be added to the polymer solution of the modified conjugated diene copolymer obtained by the above-described polymerization method. Examples of the reaction terminator that can be used include alcohols such as methanol, ethanol, and propanol; organic acids such as stearic acid, lauric acid, and octanoic acid; and water.

After carrying out the polymerization reaction of the modified conjugated diene copolymer, the metals contained in the polymer may be deashed if necessary. As a deashing method, for example, a method is used in which metals are extracted by bringing water, an organic acid, an inorganic acid, an oxidizing agent such as hydrogen peroxide into contact with a polymer solution, and then the aqueous layer is separated. .

When the modified conjugated diene polymer obtained as described above is obtained as a solution, after adding an antioxidant and additives as necessary, the solvent can be removed and dried by a normal method. can. Thereby, it can be used as a raw material for a resin composition described later. Specifically, methods include steam stripping and dehydration drying, and direct stripping methods using a drum dryer, flushing, and vent extruder.

The antioxidant is not particularly limited, and any known antioxidant can be used. Examples of the antioxidant include phenol stabilizers, phosphorus stabilizers, sulfur stabilizers, and the like. Specific examples include 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol) ) Propinate, 2-methyl-4,6-bis[(octylthio)methyl]phenol, and other antioxidants are preferred.

If necessary, water, methanol, ethanol, isopropanol, or other alcohol may be added as an additive to remove or neutralize ionic substances, or stearic acid, oleic acid, myristic acid, lauric acid, decanoic acid, Carboxylic acids such as citric acid and malic acid, aqueous inorganic acids, carbon dioxide gas, etc. may be added.

The resin composition of the present invention contains 100 parts by mass of raw rubber containing 20 parts by mass or more of a modified conjugated diene polymer, and 5 to 200 parts by mass of filler.

The content of the modified conjugated diene polymer in 100 parts by mass of the raw rubber is 20 parts by mass or more, preferably 40 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 60 parts by mass or more. When the amount is 20 parts by mass or more, the filler dispersibility that is the object of the present invention is excellent, and when the resin composition of this embodiment is made into a vulcanized composition, it has excellent properties such as tensile properties and viscoelastic properties, and is suitable for use in tires. When used as a material for tires, excellent fuel efficiency, grip performance, wear resistance, and rigidity can be obtained in the tires. Further, the content of the modified conjugated diene polymer is preferably 90 parts by mass or less, more preferably 80 parts by mass or less. When the amount is 90 parts by mass or less, the Mooney viscosity of the unvulcanized resin composition of the present invention is lowered and the processability is improved.

The raw material rubber other than the modified conjugated diene polymer is not particularly limited, and includes, for example, a conjugated diene polymer or its hydrogenated product, a random copolymer of a conjugated diene compound and a vinyl aromatic compound, or its hydrogenated product. Examples include 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, and the like.

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

Specific examples of random copolymers of conjugated diene compounds and vinyl aromatic compounds or hydrogenated products thereof are not particularly limited, and include, for example, styrene-butadiene copolymer rubber or hydrogenated products thereof.

Specific examples of block copolymers of conjugated diene compounds and vinyl aromatic compounds or hydrogenated products thereof are not particularly limited, and include, for example, styrene-butadiene block copolymers or hydrogenated products thereof, styrene-isoprene blocks. Examples include styrenic elastomers such as copolymers or hydrogenated products thereof.

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

Non-diene polymers are not particularly limited, and include, for example, 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, and butyl rubber. , brominated butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylic acid ester-conjugated diene copolymer rubber, urethane rubber, polysulfide rubber, etc. .

In the present invention, when the modified conjugated diene polymer is a modified styrene-butadiene rubber, the other rubber is preferably polybutadiene. Further, when the modified butadiene-based polymer is modified polybutadiene, natural rubber or polyisoprene rubber is preferable as the other rubber.

The weight average molecular weight of the various rubbery polymers mentioned above is preferably from 2,000 to 2,000,000, and from 5,000 to 1,500,000, from the viewpoint of the balance between performance and processing characteristics. is more preferable. Furthermore, a so-called liquid rubber having a low molecular weight can also be used. These rubbery polymers may be used alone or in combination of two or more. The weight average molecular weight here is the weight average molecular weight (Mw) in terms of polystyrene obtained by gel permeation chromatography (GPC) measurement.

The amount of filler used relative to the raw rubber is adjusted so that the more filler is used, the higher the hardness and modulus will be, and the desired physical properties will be achieved depending on the application. Within this range, filler is well dispersed and processability is good. For tire applications the filler is preferably between 5 and 150 parts by weight, and for footwear applications preferably between 30 and 200 parts by weight. Within the scope of this embodiment, it is possible to cover a wide range of materials from soft to hard.

In the resin composition of the present invention, at least one reinforcing filler selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides, and carbon black is added to 100 parts by mass of raw rubber. Contains .5 to 200 parts by mass.

As the silica-based inorganic filler contained in the resin composition, it is preferable to use solid particles whose main constituent units are SiO ₂ or silicate. Here, the main component means a component that accounts for 50% by mass or more of the whole, preferably a component that accounts for 70% by mass or more, and more preferably a component that accounts for 90% by mass or more.

Specific examples of silica-based inorganic fillers include inorganic fibrous substances such as silica, clay, talc, mica, diatomaceous earth, wallasnite, montmorillonite, zeolite, and glass fiber. The silica-based inorganic fillers may be used alone or in combination of two or more. Furthermore, a silica-based inorganic filler whose surface has been made hydrophobic, and a mixture of a silica-based inorganic filler and an inorganic filler other than silica-based filler can also be used. Among these, silica and glass fiber are preferred, and silica is more preferred.

As the silica, dry silica, wet silica, synthetic silicate silica, etc. can be used, and among these, wet silica is preferable because it is more excellent in both improving fracture characteristics and wet skid resistance performance.
As the silica, silica having a BET specific surface area of 50 to 500 m ² /g is used. By blending such silica, excellent fuel efficiency, wear resistance, wet skid performance, and handling stability can be obtained.
In addition, silica having a high specific surface area, that is, silica having a fine particle size, can also be used to achieve good dispersion. The fine particle size silica may contain silica having a CTAB (cetyltrimethylammonium bromide) specific surface area of 180 m ² /g or more and a BET specific surface area of 185 m ² /g or more. The average primary particle diameter is, for example, 25 nm or less. By blending such fine particle size silica, excellent fuel efficiency, wear resistance, wet skid performance, and handling stability can be obtained in the resin composition of this embodiment.

The aggregate size of fine particle size silica is not particularly limited and can be 30 nm or more, and by having such an aggregate size, it has excellent reinforcing properties and low fuel consumption while having good dispersibility. properties, abrasion resistance, wet skid performance, and handling stability. The aggregate size is also called the aggregate diameter or maximum frequency Stokes equivalent diameter, and is the particle diameter when a silica aggregate composed of multiple primary particles is considered as one particle. It is equivalent. The aggregate size can be measured using, for example, a disk centrifugal sedimentation type particle size distribution analyzer such as BI-XDC (manufactured by Brookhaven Instruments Corporation). Specifically, it can be measured by the method described in JP-A No. 2011-132307.
The average primary particle size of the fine particle size silica is not particularly limited, and is preferably 25 nm or less.

The amount of the fine particle size silica in the resin composition of the present invention is not particularly limited, and is preferably 5 parts by mass or more, more preferably 15 parts by mass or more, even more preferably The amount is 20 parts by mass or more, even more preferably 25 parts by mass or more, even more preferably 30 parts by mass or more. If the amount is 5 parts by mass or more, the effect of blending the above-mentioned particulate silica can be sufficiently obtained. The blending amount of the fine particle size silica is 200 parts by mass or less, preferably 100 parts by mass or less, more preferably 80 parts by mass or less, still more preferably 60 parts by mass or less, and even more preferably 55 parts by mass or less. If it is 200 parts by mass or less, substantially good workability can be obtained.

The resin composition of the present invention preferably further contains 5 to 100 parts by mass of silica or carbon black having a BET specific surface area of less than 185 m ² /g as a reinforcing filler.

In the resin composition of the present invention, silica with a BET nitrogen adsorption specific surface area (NSA) of less than 185 m ² /g is preferably used as a reinforcing filler, and more preferably silica with a nitrogen adsorption specific surface area (NSA) of less than 150 m ² /g is used. Preferably, 50 m ² /g or more is used. Within this range, there is a good balance between reinforcing properties and dispersibility. Moreover, a suitable particle size is used depending on the purpose.

As carbon black, there are N110, N220, N330, N339, N550, N660, etc. according to ASTM's classification of carbon black for rubber, and these are selected depending on the purpose. By using carbon black in combination, reinforcing properties can be enhanced, and dry grip performance can be improved when used in tire tread applications. The carbon black used has a BET nitrogen adsorption specific surface area (NSA) of preferably less than 185 m ² /g, preferably 30 m ² /g or more, and more preferably a range of 50 to 130 m ² /g. . Within this range, there is a good balance between reinforcing properties and dispersibility. When used in tire tread applications, N220, N330, and N339 are more preferred.

Furthermore, in the resin composition of the present invention, other reinforcing fillers can be used in addition to the above-mentioned silica. Other reinforcing fillers are not particularly limited, but metal oxides as reinforcing fillers have the chemical formula MxOy (M represents a metal atom, and x and y each represent an integer from 1 to 6). Preferably, the solid particles are the main component of the structure. Here, the main component means a component that accounts for 50% by mass or more of the whole, preferably a component that accounts for 70% by mass or more, and more preferably a component that accounts for 90% by mass or more.
As the metal oxide, for example, alumina, titanium oxide, magnesium oxide, zinc oxide, etc. can be used.
Examples of the metal hydroxide as a reinforcing filler include aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.
The above metal oxides and metal hydroxides as other reinforcing fillers may be used alone or in combination of two or more. Moreover, mixtures with inorganic fillers other than these can also be used.

In the resin composition of the present invention, a silane coupling agent may be used. Examples of the silane coupling agent include, but are not limited to, compounds having both a silica affinity part and a polymer affinity part in the molecule, such as sulfide compounds, mercapto compounds, vinyl compounds, amino compounds, Examples include glycidoxy compounds, nitro compounds, chloro compounds, and the like.
Examples of sulfide compounds include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, and bis(2-trimethoxysilylpropyl)tetrasulfide. silylethyl) tetrasulfide, bis(3-triethoxysilylpropyl) trisulfide, bis(3-trimethoxysilylpropyl) trisulfide, bis(3-triethoxysilylpropyl) disulfide, bis(3-trimethoxysilylpropyl) Disulfide, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 2-trimethoxysilylethyl-N,N-dimethylthiocarbamoyl Tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, 3-octanoylthio-1 -Propyltriethoxysilane and the like.
Examples of the mercapto compound include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane.
Examples of vinyl compounds include vinyltriethoxysilane and vinyltrimethoxysilane.
Examples of amino compounds include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxy. Examples include silane.
Examples of glycidoxy compounds include γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycidoxypropylmethyldimethoxysilane. Can be mentioned.
Examples of the nitro compound include 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane.
Examples of the chloro-based compound include 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane.
Examples of other compounds include octyltriethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, and hexadecyltrimethoxysilane.

These silane coupling agents may be used alone or in combination of two or more. Among these silane coupling agents, sulfur-containing silane coupling agents such as sulfide compounds and mercapto compounds are preferred from the viewpoint of a large reinforcing effect, and bis(3-triethoxysilylpropyl) disulfide, bis(3- More preferred are triethoxysilylpropyl) tetrasulfide and 3-mercaptopropyltrimethoxysilane.
The amount of the silane coupling agent blended is 1 to 20 parts by weight, preferably 2 to 15 parts by weight, per 100 parts by weight of silica. When the silane coupling agent is blended within this range, the dispersibility of silica is further improved, processability is improved, and the performance of the vulcanized rubber is improved, such as improved abrasion resistance.

In the resin composition of the present invention, hardness and modulus can be adjusted by using a plasticizer. The plasticizer is not particularly limited, but for example, oils similar to the above-mentioned extender oil can be used, and in addition, various natural oils, synthetic oils, low molecular weight polymers, etc. can be used. Additionally, known processing aids can be used.

The resin composition of the present invention may be a resin composition further subjected to crosslinking treatment by adding a vulcanizing agent (crosslinking agent), a compounding agent, etc. Such a crosslinking agent is not particularly limited, but for example, a sulfur-based vulcanizing agent, an organic peroxide, etc. can be used.
Examples of the sulfur-based vulcanizing agent include, but are not limited to, sulfur and morpholine disulfide. Examples of the organic peroxide include benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, and the like. T-butylcumyl peroxide, cumene hydroperoxide, etc. are used.
The amount of the vulcanizing agent used is not particularly limited, but it is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 15 parts by weight, based on 100 parts by weight of the conjugated diene copolymer. As the vulcanization method, conventionally known methods can be applied, and the vulcanization temperature is preferably, for example, 120°C to 200°C, more preferably 140°C to 180°C.
If necessary, a vulcanization accelerator or vulcanization aid may be added, and examples of the vulcanization accelerator include, but are not limited to, sulfenamide, thiazole, thiuram, thiourea, and guanidine. A vulcanization accelerator containing at least one of a vulcanization accelerator based on a dithiocarbamate type, a dithiocarbamate type, an aldehyde-amine type, an aldehyde-ammonia type, an imidazoline type, or a xanthate type can be used.

Further, a vulcanization aid may be blended as necessary, and the vulcanization aid is not particularly limited, but for example, zinc oxide, stearic acid, etc. can be used. Furthermore, anti-aging agents can be used.

The resin composition of the present invention can be produced by mixing the above components.
A modified conjugated diene copolymer, at least one reinforcing filler selected from the group consisting of silica-based inorganic fillers, metal oxides, metal hydroxides, and carbon black, and optionally a silane coupling agent. There are no particular limitations on the method of mixing. For example, a melt-kneading method using a general mixing machine such as an open roll, a Banbury mixer, a kneader, a single screw extruder, a twin screw extruder, a multi-screw extruder, etc. After dissolving and mixing each component, a solvent is added. Examples include a method of removing by heating. Among these, melt-kneading methods using rolls, Banbury mixers, kneaders, and extruders are preferred from the viewpoint of productivity and good kneading properties. Further, it is possible to apply either a method of kneading the rubber component and various compounding agents at once or a method of mixing them in a plurality of batches.

In the present invention, the degree of polymer concentration ability on the surface of the filler can be expressed by the amount of bound rubber (bound rubber production ability) of the modified conjugated diene polymer at 25°C. The amount of bound rubber in the resin composition after the above-mentioned kneading is preferably 15% by mass or more, more preferably 20% by mass or more from the viewpoint of improving wear resistance and fracture strength.

The resin composition may be a vulcanized composition subjected to vulcanization treatment using a vulcanizing agent. As the vulcanizing agent, for example, radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds can be used. Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, polymeric polysulfur compounds, and the like.

During vulcanization, a vulcanization accelerator may be used as necessary. As the vulcanization accelerator, conventionally known materials can be used, such as sulfenamide type, guanidine type, thiuram type, aldehyde-amine type, aldehyde-ammonia type, thiazole type, thiourea type, dithiocarbamate type. Vulcanization accelerators such as As the vulcanization aid, zinc white, stearic acid, etc. can be used.

A rubber softener may be added to the resin composition of the present invention in order to improve processability. As the rubber softener, mineral oil, liquid or low molecular weight synthetic softeners are suitable.

A mineral oil-based rubber softener called process oil or extender oil, which is used to soften, increase volume, and improve processability of rubber, is a mixture of aromatic rings, naphthenic rings, and paraffin chains. Those in which the number of carbon atoms in the paraffin chain accounts for 50% or more of the total carbons are called paraffinic, those in which the number of carbon atoms in the naphthene ring is 30 to 45% are called naphthenic, and those in which the number of aromatic carbons exceeds 30% are called aromatic. It is called a system. The rubber softener used in this embodiment is preferably a naphthenic and/or paraffinic softener.

The amount of the rubber softener blended is not particularly limited, but is preferably 10 to 80 parts by weight, more preferably 20 to 50 parts by weight, based on 100 parts by weight of the conjugated diene copolymer.

The resin composition of the present invention may contain softeners and fillers other than those mentioned above, as well as heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, and coloring agents, within a range that does not impair the purpose of the present embodiment. Various additives such as agents and lubricants may also be used. Specific examples of the filler include calcium carbonate, magnesium carbonate, aluminum sulfate, barium sulfate, and the like.
Examples of softeners that may be added as needed to adjust the hardness and fluidity of the desired product include liquid paraffin, castor oil, and linseed oil. Known materials can be used as the heat stabilizer, antistatic agent, weather stabilizer, anti-aging agent, colorant, and lubricant.

The crosslinked resin product of the present invention is obtained by crosslinking a resin composition. For example, tires are manufactured by extruding and molding a resin composition according to the shape of the tire (for example, tread shape), and heating and pressurizing this in a vulcanizer to produce a tread. By assembling the parts, the desired tire can be manufactured.

The resin composition of the present invention has excellent mechanical strength and abrasion resistance when made into a resin crosslinked product. Therefore, as described above, it can be suitably applied to treads of tires such as fuel-efficient tires, large tires, and high-performance tires, and structural members such as sidewall members. In addition to structural members, it can also be suitably used for rubber belts, rubber hoses, footwear materials, etc.

Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. In addition, all parts in each example are parts by weight unless otherwise specified, and evaluation of each physical property was performed by the method shown below.

1) Molecular weight and molecular weight distribution, area (%) of hyperbranched components and area (%) of 3 Mp or more
Molecular weight and molecular weight distribution measurements were performed using GPC (HLC-8220GPC, manufactured by Tosoh), and the analytical columns were TSKgel MultiporeH _XL -M (manufactured by Tosoh): 2, TSKgel G1000H _XL : 1, and the guard column was TSKguardcolumn MP (XL). ): using tetrahydrofuran (THF) as a solvent, a flow rate of 1.0 ml/min, a column temperature of 38° C., and a calibration curve using monodisperse polystyrene.
In addition, as shown in Figure 1, the area (%) of the hyperbranched component of the modified conjugated diene copolymer has a molecular weight that is twice the peak top molecular weight Mp of the uncoupled, unbranched diene copolymer. (2Mp) or more. Furthermore, the area (%) of 3 Mp or more indicates the area % of a molecular weight range that is three times the molecular weight (3 Mp) or more of the peak top molecular weight Mp of the uncoupled, unbranched diene copolymer.

2) Structure of modified vinyl aromatic copolymer Determined by ¹³ C-NMR and ¹ H-NMR analysis using a JNM-LA600 nuclear magnetic resonance spectrometer manufactured by JEOL. Chloroform-d ₁ was used as the solvent and the resonance line of tetramethylsilane was used as the internal standard.
3) Solvent soluble (cyclohexane)
5.0 g of modified vinyl aromatic copolymer was dissolved in 95.0 g of cyclohexane, filtered through a glass filter, the filtered glass filter was washed with 30 g of cyclohexane, and the glass filter was vacuum dried at 60°C. . Then, the weight of the polymer on the filter is calculated. If the dry weight of the polymer is less than 0.025g, it is ○, if it is 0.025g or more and less than 0.25g, it is △, and if it is 0.25g or more, it is ×

4) Mooney viscosity It was determined in accordance with JIS K6300-1 using an L-shaped rotor, preheating for 1 minute, rotor operating time for 4 minutes, and a temperature of 100°C.
5) Gel content To a sample in which 0.5 g of copolymer rubber was dissolved in 100 mL of toluene, 1.0 g of 0.2 wt % Sudan III toluene solution was added and left for 1 hour. This sample solution is filtered through a 0.2 μm PTFE membrane filter, and the membrane filter is vacuum dried at 40°C. Visually observe the gel content colored with Sudan III on the membrane filter after drying. When the gel content is 0, it is marked as ○, when it is 1 to 5, it is △, and when it is 6 or more, it is marked as ×. did.

6) Thermogravimetry (TGA)
The weight loss (TGA ₃₅₀ ) at 350°C was determined according to JIS K7120.

7) Haze
A sample in which 0.5 g of copolymer rubber was dissolved in 100 g of toluene was placed in a quartz cell, and its haze (turbidity) was measured using an integrating sphere light transmittance measuring device (manufactured by Nippon Denshoku Co., Ltd., using toluene as a reference sample). The Haze value was measured using SZ-Σ90).

8) Content of vinyl bonds in conjugated diene copolymer (SBR) Using a carbon disulfide solution as the sample, measure the infrared spectrum in the range of 600 to 1000 cm-1 using a solution cell, and calculate the absorbance at a predetermined wave number. The amount of vinyl bonds (%) in the conjugated diene copolymer (SBR) was determined according to the calculation formula of the Hampton (styrene-butadiene copolymer) method. The device used was Spectrum 100 manufactured by PerkinElmer.

9) Amount of Bound Rubber After kneading, 0.4 g of unvulcanized rubber was cut into 2 mm square pieces, placed in a sample tube together with 50 mL of toluene, and allowed to stand at room temperature for 48 hours. Thereafter, extraction was performed using a glass filter, and the toluene solution portion and the rubber portion were each dried. Then, the weight of the rubber portion on the filter was calculated and determined as the amount of bound rubber. Furthermore, the dried toluene solution portion was dissolved in chloroform, the proportion of polybutadiene was calculated by proton NMR, and this value was used to calculate back from the actual number of blended parts to determine the amount of bound rubber of polybutadiene. The bound rubber amount of Comparative Example 3 was set as 100 and expressed as an index.

10) Tensile Strength The 300% modulus was measured by the tensile test method of JIS K6251, and the measured value of the crosslinked rubber obtained in Comparative Example 3 was set as 100, and was converted into an index. The larger the index value, the better the tensile strength.

11) Abrasion resistance Using a method using a Lambourn type abrasion tester based on JIS K6264, the amount of wear at a slip rate of 25% was measured, and the measured value of the crosslinked rubber obtained in Comparative Example 3 was set as 100. Indexed. The measurement temperature was room temperature. The larger the index value, the better the wear resistance.

The raw materials or their abbreviations used in the examples are as follows.
DVB-810; mixture of divinylbenzene component and ethylvinylbenzene component; divinylbenzene component content 81.0wt%, manufactured by Nippon Steel Chemical & Materials)

Example 1 Synthesis of modified vinyl aromatic copolymer (A-1) 270 ml (210.3 g) of ethylcyclohexane, 1.35 ml (7.0 mmol) of cocatalyst 2,2-di(2-tetrahydrofuryl)propane. After charging and adding 21.9 ml of n-hexane solution containing 2.24 g (35.0 mmol) of n-butyllithium (the following structural formula) as a pure component at 30°C,

A solution prepared by dissolving 2.77 g (17.5 mmol) of 1,3-diisopropenylbenzene (the following structural formula) from which impurities had been removed in 40 ml (31.2 g) of ethylcyclohexane was added over 1 hour. Stirring was continued for 30 minutes at 30°C.

Next, a solution of 25.5 g (0.245 mol) of styrene (the following structural formula) dissolved in 10 ml (7.8 g) of ethylcyclohexane was added over 30 minutes to initiate the first stage polymerization.

The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 67°C. After the polymerization reaction was completed, a small sample of the polymerization solution was analyzed by gas chromatography (GC), and no unreacted monomer was observed, confirming that the polymerization conversion rate was approximately 100%.
Next, 7.15 g (105 mmol) of isoprene (the following structural formula) was added as an additional monomer to the reactor, and the second stage of polymerization was started at 30°C.

After the second stage polymerization reaction was completed, a small sample of the polymerization solution was subjected to GC analysis, and it was confirmed that no unreacted monomer was observed and the polymerization conversion rate was approximately 100%. GPC analysis revealed that the copolymer had Mn of 1940, Mw of 2410, and Mw/Mn of 1.24 at the end of the second stage of polymerization.
Next, 8.73 g (35.0 mmol) of diethylaminomethyltriethoxysilane (DEAMTES) was added as a modifier and a modification reaction was carried out for 2 hours to obtain a polymer solution containing a modified vinyl aromatic copolymer. After the polymerization reaction was completed, 8.27 g (70.0 mmol) of succinic acid as a neutralizing agent was added, stirred, and then filtered.
Here, DEAMTES is a modifier having both an alkoxysilyl group and an amino group, as shown in the structural formula below.

When the obtained polymerization solution was concentrated by devolatilization and then dissolved in ethylcyclohexane, no formation of gel or microgel was observed. As a result, 41.74 g (yield: 98.0 wt%) of modified vinyl aromatic copolymer A-1 was obtained in terms of solid content.
Table 1 shows the analysis results of modified vinyl aromatic copolymer A-1.

The obtained modified vinyl aromatic copolymer A-1 had Mn of 2940, Mw of 4140, and Mw/Mn of 1.41. By performing GC analysis, ¹³ C-NMR and ¹ H-NMR analysis, modified vinyl aromatic copolymer A-1 contained 4.35 mol% (6.50 wt. %), 60.87 mol% (59.91 wt%) of structural units derived from styrene, 26.09 mol% (16.79 wt%) of structural units derived from isoprene, and diethylaminomethyltriethoxysilane (DEAMTES). ) Contains 8.70 mol % (16.79 wt %) of structural units derived from ), and it was confirmed that 2.42 modifiers were introduced per molecule of the modified vinyl aromatic copolymer. did. Since the polyfunctional structural unit (e1) represented by the formula (1) was 4.22 mol% (6.31 wt%), the polyfunctional structural degree (e1/c) was 0.97. In formula (1), R1 is phenyl, R2 is methyl, and R3 is n-pentyl. The structural unit derived from diisopropenylbenzene having a residual vinyl group contained in the modified vinyl aromatic copolymer (A-1) was 1.31 mol% (1.92 wt%). Modifier bound to isoprene-derived units was 93.6 mol%.
As a result of thermogravimetric analysis (TGA), the weight loss at 350°C (TGA ₃₅₀ ) was 0.64 wt%. A sample in which 0.5 g of modified vinyl aromatic copolymer (A-1) was dissolved in 100 g of toluene was placed in a quartz cell, and its haze (turbidity) was measured using an integrating sphere light transmittance method using toluene as a reference sample. The Haze value measured using a measuring device was 0.02.

Comparative Example 1 Synthesis of modified vinyl aromatic copolymer (B-1) Divinylbenzene (mixture of 1,4-divinylbenzene and 1,3-divinylbenzene, the same applies to the following examples) 4.37 mol (630. 2 mL), ethylvinylbenzene (a mixture of 1-ethyl-4-vinylbenzene and 1-ethyl-3-vinylbenzene, the same applies to the following examples) 3.34 mol (457.5 mL), anisole (the following structural formula) 6.90 mol (749.9 mL) and 345 mL of toluene were charged into a 3.0 L reactor, and 103.5 mmol (13.0 mL) of boron trifluoride diethyl ether complex was added at 50°C. Allowed time to react.

After stopping the polymerization solution with an aqueous sodium hydrogen carbonate solution, the oil layer was washed three times with pure water, devolatilized under reduced pressure at 60° C., and the polymer was recovered. The obtained polymer was weighed and it was confirmed that 945.3 g of copolymer B-1 was obtained.

The obtained copolymer B-1 had Mn of 624, Mw of 2360, and Mw/Mn of 3.79, and was a random copolymer. By performing ¹³ C-NMR and ¹ H-NMR analysis, a resonance line of a terminal group in which a benzene ring derived from anisole was bonded to the terminal of the main chain was observed in the NMR chart of copolymer B-1.
The amount of anisole-derived structural units introduced into the soluble polyfunctional vinyl aromatic polymer calculated from the elemental analysis results and the number average molecular weight in terms of standard polystyrene was 1.6 (units/molecule). Further, it contained 61.3 mol% of structural units derived from divinylbenzene and 38.7 mol% in total of structural units derived from ethylvinylbenzene (excluding terminal structural units). The vinyl group content contained in copolymer B-1 was 34.8 mol% (excluding terminal structural units). Furthermore, the polyfunctional structural unit (e1) having a plurality of organic groups derived from the organic alkali metal compound represented by the above formula (1) was not observed.
Further, as a result of TMA measurement of the cured product, no clear Tg was observed, and the softening temperature was 300° C. or higher. As a result of TGA measurement, the weight loss at 350° C. was 3.70 wt%, and the heat discoloration resistance was rated ◯.
Copolymer B-1 was soluble in toluene, xylene, THF, dichloroethane, dichloromethane, and chloroform, and no gel formation was observed.

Comparative Example 2 Synthesis of polysiloxane-modified crosslinked polymer particles (C-1) 45 parts of divinylbenzene (purity 56%, remaining 38% is ethylvinylbenzene, remaining 6% is impurity, this divinylbenzene will be used hereinafter), styrene 55 parts of sodium dodecylbenzenesulfonate, 3 parts of sodium dodecylbenzenesulfonate, 0.5 parts of polyvinyl alcohol, 1000 parts of ion-exchanged water, and 0.7 parts of α,α'-azoisobutyronitrile were charged into a reaction vessel, and the mixture was heated at 15,000 rpm using a homomixer. The mixture was stirred for 60 minutes to make it homogeneous. Next, the mixture was heated to 80° C. while blowing nitrogen gas, and stirring was continued for 3 hours to carry out suspension polymerization to obtain polymer particles (C-0). Next, while maintaining the temperature of the reaction vessel at 25° C., the pH was adjusted to 8.0, 30 parts of methyltriethoxysilane (MTES: structural formula shown below) was added, and the mixture was vigorously stirred for about 30 minutes.

Thereafter, the temperature of the reaction vessel was raised to 70° C., and the reaction was carried out for 3 hours to complete the condensation reaction and produce crosslinked polymer particles C-1. No coagulum formation was observed in this dispersion. The average particle diameter of the obtained crosslinked polymer particles a was measured and found to be 1.9 μm. When the resulting water slurry of crosslinked polymer particles was centrifugally washed and subjected to elemental analysis by ESCA, the presence of Si element was observed.

Example 2 Synthesis of modified vinyl aromatic copolymer (D-1) 270 ml (210.3 g) of ethylcyclohexane and 1.35 ml (7.0 mmol) of 2,2-di(2-tetrahydrofuryl)propane were charged. Then, at 30°C, 21.9 ml of n-hexane solution containing 2.24 g (35.0 mmol) of pure n-butyllithium was added, and then DVB-810 from which impurities had been removed in advance (divinylbenzene, divinylbenzene, Shows the structural formula of ethylvinylbenzene) 2.82g (divinylbenzene (mixture of m-form and p-form) component 17.5 mmol, ethylvinylbenzene (mixture of m-form and p-form) component 4.16 mmol) A solution of was dissolved in 40 ml (31.2 g) of ethylcyclohexane was added over 1 hour. Stirring was continued for 30 minutes at 30°C.

Next, a solution of 25.5 g (0.245 mol) of styrene dissolved in 10 ml (7.8 g) of ethylcyclohexane was added over 30 minutes to initiate the first stage of polymerization. The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 62°C. After the polymerization reaction was completed, a small sample of the polymerization solution was analyzed by gas chromatography (GC), and no unreacted monomer was observed, confirming that the polymerization conversion rate was approximately 100%.
Next, 7.15 g (105 mmol) of isoprene was added as an additional monomer to the reactor to initiate the second stage polymerization at 30°C. After the second stage polymerization reaction was completed, a small sample of the polymerization solution was subjected to GC analysis, and it was confirmed that no unreacted monomer was observed and the polymerization conversion rate was approximately 100%. GPC analysis revealed that the copolymer had an Mn of 1970, an Mw of 2630, and an Mw/Mn of 1.34 at the end of the second stage of polymerization.
Next, 8.73 g (35.0 mmol) of diethylaminomethyltriethoxysilane (DEAMTES) was added as a modifier and a modification reaction was carried out for 2 hours to obtain a polymer solution containing a modified vinyl aromatic copolymer. After the polymerization reaction was completed, 8.27 g (70.0 mmol) of succinic acid was added, stirred, and then filtered.
When the obtained polymerization solution was concentrated by devolatilization and then dissolved in ethylcyclohexane, no formation of gel or microgel was observed. As a result, 38.51 g (yield: 96.7 wt%) of modified vinyl aromatic copolymer D-1 was obtained in terms of solid content.
Table 1 shows the analysis results of modified vinyl aromatic copolymer D-1.

The obtained modified vinyl aromatic copolymer D-1 had Mn of 2650, Mw of 3910, and Mw/Mn of 1.48. By performing GC analysis, ¹³ C-NMR and ¹ H-NMR analysis, modified vinyl aromatic copolymer D-1 contained 4.50 mol% (5.34 wt%) of structural units derived from divinylbenzene. , 1.03 mol% (1.27 wt%) of structural units derived from ethylvinylbenzene, 60.25 mol% (59.84 wt%) of structural units derived from styrene, and 25.82 mol% (59.84 wt%) of structural units derived from isoprene. Modified vinyl aromatic copolymer 1 contains mol% (16.77wt%) and 8.61 mol% (16.77wt%) of structural units derived from diethylaminomethyltriethoxysilane (DEAMTES). It was confirmed that 2.33 modifiers were introduced per molecule. Since the content of the polyfunctional structural unit (e1) represented by the formula (1) is 3.33 mol% (3.95 wt%), the polyfunctional structural degree (e1/c) is 0.74. there were. In formula (1), R1 is phenyl, R2 is hydrogen, and R3 is n-pentyl. The content of divinylbenzene-derived structural units having residual vinyl groups contained in the modified vinyl aromatic copolymer (D-1) was 1.82 mol% (0.21 wt%). Modifier bound to isoprene-derived units was 89.3 mol%.
As a result of thermogravimetry (TGA), the weight loss (TGA ₃₅₀ ) at 350° C. was 0.78 wt%. A sample in which 0.5 g of modified vinyl aromatic copolymer (D-1) was dissolved in 100 g of toluene was placed in a quartz cell, and its haze (turbidity) was measured using an integrating sphere light transmittance method using toluene as a reference sample. The Haze value measured using a measuring device was 0.06.

Example 3 Synthesis of modified vinyl aromatic copolymer (E-1) 270 ml (210.3 g) of ethylcyclohexane and 1.35 ml (7.0 mmol) of 2,2-di(2-tetrahydrofuryl)propane were charged. Then, at 30°C, 21.9 ml of n-hexane solution containing 2.24 g (35.0 mmol) of pure n-butyllithium was added, and then 1,3-diisopropenylbenzene 2 from which impurities had been removed in advance was added. A solution of .77 g (17.5 mmol) dissolved in 40 ml (31.2 g) of ethylcyclohexane was added over 1 hour. Stirring was continued for 30 minutes at 30°C.
Next, a solution of 25.5 g (0.245 mol) of styrene dissolved in 10 ml (7.8 g) of ethylcyclohexane was added over 30 minutes to initiate the first stage of polymerization. The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 64°C. After the polymerization reaction was completed, a small sample of the polymerization solution was analyzed by gas chromatography (GC), and no unreacted monomer was observed, confirming that the polymerization conversion rate was approximately 100%.
Next, 7.15 g (105 mmol) of isoprene was added as an additional monomer to the reactor to initiate the second stage polymerization at 30°C. After the second stage polymerization reaction was completed, a small sample of the polymerization solution was subjected to GC analysis, and it was confirmed that no unreacted monomer was observed and the polymerization conversion rate was approximately 100%. GPC analysis revealed that the copolymer had Mn of 2010, Mw of 2490, and Mw/Mn of 1.24 at the end of the second stage of polymerization.
Next, 9.74 g (35.0 mmol) of 3-glycidoxypropyltriethoxysilane (GPTES) shown by the following structural formula was added as a modifier, and a modification reaction was carried out for 2 hours. A polymer solution containing coalescence was obtained.

After the polymerization reaction was completed, 8.27 g (70.0 mmol) of succinic acid was added, stirred, and then filtered.
When the obtained polymerization solution was concentrated by devolatilization and then dissolved in ethylcyclohexane, no formation of gel or microgel was observed. As a result, 42.89 g (yield: 97.6 wt%) of modified vinyl aromatic copolymer E-1 was obtained in terms of solid content.
Table 1 shows the analysis results of modified vinyl aromatic copolymer E-1.

The obtained modified vinyl aromatic copolymer E-1 had Mn of 3170, Mw of 4600, and Mw/Mn of 1.45. By performing GC analysis, ¹³ C-NMR and ¹ H-NMR analysis, modified vinyl aromatic copolymer E-1 contained 4.35 mol% (6.30 wt. %), 60.87 mol% (58.07 wt%) of structural units derived from styrene, 26.09 mol% (16.28 wt%) of structural units derived from isoprene, and Contains 8.70 mol% (19.35 wt%) of structural units derived from ethoxysilane (GPTES), and 2.53 modifiers are introduced per molecule of the modified vinyl aromatic copolymer. I confirmed that there is. Since the content of the polyfunctional structural unit (e1) represented by the above formula (1) is 4.26 mol% (6.17 wt%), the polyfunctional structural degree (e1/c) is 0.98. there were. In formula (1), R1 is phenyl, R2 is methyl, and R3 is n-pentyl. The content of structural units derived from diisopropenylbenzene having residual vinyl groups contained in the modified vinyl aromatic copolymer (A-1) was 0.94 mol% (1.32 wt%). Modifier bound to isoprene-derived units was 94.2 mol%.
As a result of thermogravimetric analysis (TGA), the weight loss at 350°C (TGA ₃₅₀ ) was 0.81 wt%. A sample in which 0.5 g of modified vinyl aromatic copolymer (E-1) was dissolved in 100 g of toluene was placed in a quartz cell, and its haze (turbidity) was measured using an integrating sphere light transmittance method using toluene as a reference sample. The Haze value measured using a measuring device was 0.03.

Table 1 shows the analysis results of the copolymers of Examples 1, 2, and 3 and Comparative Examples 1 and 2.

Example 4 Synthesis of modified conjugated diene copolymer (A-2) Into a nitrogen-purged autoclave reactor, 580 g of cyclohexane and 30.7 mg (0.16 mmol) of 2,2-di(2-tetrahydrofuryl)propane were added. After adding 15 g of a cyclohexane solution containing 51.2 mg (0.80 mmol) of n-butyllithium as a pure component at 50°C, 34.29 g of styrene from which impurities had been removed in advance, 1 , 3-butadiene (80.00 g) was added to initiate polymerization. The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 73°C. After the completion of the polymerization reaction, 15 g of a cyclohexane solution containing 0.487 g of the modified vinyl aromatic copolymer (A-1) obtained in Example 1 was used as an SBR modifier to modify the obtained styrene-butadiene rubber (SBR). was added and a modification reaction was carried out.The modification reaction was carried out for 30 minutes at a temperature of 60°C to obtain a polymer solution.
Furthermore, 0.40 mmol of 3-glycidoxypropyltriethoxysilane (GPTES) was added and a modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.
After adding 0.045 g of 2,6-di-tert-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the modified conjugated diene-based conjugate was vacuum dried. Polymer (modified SBR) A-2 was obtained.
Table 2 shows the analysis results of modified conjugated diene copolymer A-2.

Comparative Example 3 Synthesis of modified conjugated diene copolymer (B-2) Into a nitrogen-purged autoclave reactor, 580 g of cyclohexane and 30.7 mg (0.16 mmol) of 2,2-di(2-tetrahydrofuryl)propane were added. After adding 15 g of a cyclohexane solution containing 51.2 mg (0.80 mmol) of n-butyllithium as a pure component at 50°C, 34.29 g of styrene from which impurities had been removed in advance, 1 , 3-butadiene (80.00 g) was added to initiate polymerization. The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 79°C. After the polymerization reaction was completed, 15 g of a cyclohexane solution containing 0.379 g of the modified vinyl aromatic copolymer (B-1) obtained in Comparative Example 1 as an SBR modifier was added, and the modification reaction was carried out at 60 ° C. A denaturation reaction was carried out for 30 minutes under temperature conditions to obtain a polymer solution.
Furthermore, 0.40 mmol of 3-glycidoxypropyltriethoxysilane (GPTES) was added and a modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.
After adding 0.045 g of 2,6-di-tert-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the modified conjugated diene-based conjugate was vacuum dried. Polymer B-2 was obtained.
Table 2 shows the analysis results of modified conjugated diene copolymer (modified SBR) B-2.

Comparative Example 4 Synthesis of modified conjugated diene copolymer (C-2) Into a nitrogen-purged autoclave reactor, 580 g of cyclohexane and 30.7 mg (0.16 mmol) of 2,2-di(2-tetrahydrofuryl)propane were added. After adding 15 g of a cyclohexane solution containing 51.2 mg (0.80 mmol) of n-butyllithium as a pure component at 50°C, 34.29 g of styrene from which impurities had been removed in advance, 1 , 3-butadiene (80.00 g) was added to initiate polymerization. The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 79°C. After the polymerization reaction was completed, 15 g of a cyclohexane solution containing 0.466 g of the modified vinyl aromatic copolymer (C-1) obtained in Comparative Example 2 as an SBR modifier was added, and the modification reaction was carried out at 60 ° C. A denaturation reaction was carried out for 30 minutes under temperature conditions to obtain a polymer solution.
Furthermore, 0.40 mmol of 3-glycidoxypropyltriethoxysilane (GPTES) was added and a modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.
After adding 0.045 g of 2,6-di-tert-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the modified conjugated diene-based copolymer was dried in vacuum. Polymer C-2 was obtained.
Table 2 shows the analysis results of modified conjugated diene copolymer (modified SBR) C-2.

Example 5 Synthesis of modified conjugated diene copolymer (D-2) Into a nitrogen-purged autoclave reactor, 580 g of cyclohexane and 30.7 mg (0.16 mmol) of 2,2-di(2-tetrahydrofuryl)propane were added. After adding 15 g of a cyclohexane solution containing 51.2 mg (0.80 mmol) of n-butyllithium as a pure component at 50°C, 34.29 g of styrene from which impurities had been removed in advance, 1 , 3-butadiene (80.00 g) was added to initiate polymerization. The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 75°C. After the polymerization reaction was completed, 15 g of a cyclohexane solution containing 0.455 g of the modified vinyl aromatic copolymer (D-1) obtained in Example 2 was added as an SBR modifier to modify the obtained styrene-butadiene rubber (SBR). was added and a modification reaction was carried out.The modification reaction was carried out for 30 minutes at a temperature of 60°C to obtain a polymer solution.
Furthermore, 0.40 mmol of 3-glycidoxypropyltriethoxysilane (GPTES) was added and a modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.
After adding 0.045 g of 2,6-di-tert-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the modified conjugated diene-based copolymer was dried in vacuum. Polymer D-2 was obtained.
Table 2 shows the analysis results of modified conjugated diene copolymer (modified SBR) D-2.

Example 6 Synthesis of modified conjugated diene copolymer (E-2) Into a nitrogen-purged autoclave reactor, 580 g of cyclohexane and 30.7 mg (0.16 mmol) of 2,2-di(2-tetrahydrofuryl)propane were added. After adding 15 g of a cyclohexane solution containing 51.2 mg (0.80 mmol) of n-butyllithium as a pure component at 50°C, 34.29 g of styrene from which impurities had been removed in advance, 1 , 3-butadiene (80.00 g) was added to initiate polymerization. The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 81°C. After the polymerization reaction was completed, 15 g of a cyclohexane solution containing 0.502 g of the modified vinyl aromatic copolymer (E-1) obtained in Example 3 was used as an SBR modifier to modify the obtained styrene-butadiene rubber (SBR). was added and a modification reaction was carried out.The modification reaction was carried out for 30 minutes at a temperature of 60°C to obtain a polymer solution.
Furthermore, 0.40 mmol of 3-glycidoxypropyltriethoxysilane (GPTES) was added and a modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.
After adding 0.045 g of 2,6-di-tert-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the modified conjugated diene-based conjugate was vacuum dried. Polymer E-2 was obtained.
Table 2 shows the analysis results of modified conjugated diene copolymer (modified SBR) E-2.

Example 7
The modified conjugated diene copolymer (modified SBR) A-2 obtained in Example 4, process oil, carbon black, zinc oxide, stearic acid, and anti-aging agent were blended, and the mixture was heated at 155°C using a Labo Plastomill. The mixture was kneaded for 4 minutes at 60 rpm.
Sulfur and a vulcanization accelerator were added to the obtained kneaded product, and the mixture was kneaded using a Labo Plastomill at 70° C. and 60 rpm for 1 minute, followed by vulcanization to obtain a crosslinked rubber A-3.
Table 3 shows the blending ratio of each additive, and Table 4 shows the physical properties of the obtained crosslinked rubber.

The additives used are as follows.
Silica: Evonik Degussa, ULTRASIL 7000
Carbon black: Niteron #200IS manufactured by Nichinka Carbon Co., Ltd.
Zinc oxide: Manufactured by Sakai Chemicals Zinc oxide type 2 Stearic acid: Manufactured by Fuji Film Wako Pure Chemical Industries Antioxidant: Manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Nocrack 6C
Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry JIS Class 2 vulcanization accelerator A: Noxeler CZ-G manufactured by Ouchi Shinko Chemical Industry
Vulcanization accelerator B: Noxela DP manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

Examples 8 and 9, Comparative Examples 5 and 6
Instead of the modified conjugated diene copolymer (modified SBR) A-2, the modified conjugated diene copolymer (modified SBR) B- synthesized in Example 5, Example 6, or Comparative Example 3 or Comparative Example 4 Crosslinked rubbers B-3, C-3, D-3, and E-3 were obtained in the same manner as in Example 7, except that 2, C-2, D-2, and E-2 were used.
Table 4 shows the physical properties of the obtained crosslinked rubber.

Example 10 Synthesis of modified vinyl aromatic copolymer (F-1) 270 ml (210.3 g) of cyclohexane and 5.08 ml (35.0 mmol) of cocatalyst triethylamine were charged, and at 30°C, sec-butyllithium was added. After adding 21.9 ml of n-hexane solution containing 2.24 g (35.0 mmol) of (the following structural formula) as pure content,

A solution prepared by dissolving 2.77 g (17.5 mmol) of 1,3-diisopropenylbenzene (the following structural formula) from which impurities had been removed in 40 ml (31.2 g) of cyclohexane was added over 3 hours. Stirring was continued for 2 hours at 30°C.

Next, a solution of 25.5 g (0.245 mol) of styrene (the following structural formula) dissolved in 10 ml (7.8 g) of cyclohexane was added over 30 minutes to initiate the first stage of polymerization.

The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 62°C. After the polymerization reaction was completed, a small sample of the polymerization solution was analyzed by gas chromatography (GC), and no unreacted monomer was observed, confirming that the polymerization conversion rate was approximately 100%.
Next, 7.15 g (105 mmol) of isoprene (the following structural formula) was added as an additional monomer to the reactor over 15 minutes to initiate the second stage polymerization at 30°C.

After the second stage polymerization reaction was completed, a small sample of the polymerization solution was subjected to GC analysis, and it was confirmed that no unreacted monomer was observed and the polymerization conversion rate was approximately 100%. GPC analysis revealed that the copolymer had Mn of 1870, Mw of 2410, and Mw/Mn of 1.29 at the end of the second stage of polymerization.
Next, 8.73 g (35.0 mmol) of diethylaminomethyltriethoxysilane (DEAMTES) was added as a modifier and a modification reaction was carried out for 2 hours to obtain a polymer solution containing a modified vinyl aromatic copolymer. After the polymerization reaction was completed, 8.27 g (70.0 mmol) of succinic acid as a neutralizing agent was added, stirred, and then filtered.
Here, DEAMTES is a modifier having both an alkoxysilyl group and an amino group, as shown in the structural formula below.

When the obtained polymerization solution was concentrated by devolatilization and then dissolved in ethylcyclohexane, no formation of gel or microgel was observed. As a result, 41.31 g (yield: 97.0 wt%) of modified vinyl aromatic copolymer F-1 was obtained in terms of solid content.
Table 5 shows the analysis results of modified vinyl aromatic copolymer F-1.

The obtained modified vinyl aromatic copolymer F-1 had Mn of 2760, Mw of 4080, and Mw/Mn of 1.48. By performing GC analysis, ¹³ C-NMR and ¹ H-NMR analysis, modified vinyl aromatic copolymer F-1 contained 4.35 mol% (6.50 wt. %), 60.87 mol% (59.91 wt%) of structural units derived from styrene, 26.09 mol% (16.79 wt%) of structural units derived from isoprene, and diethylaminomethyltriethoxysilane (DEAMTES). ) Contains 8.70 mol % (16.79 wt %) of structural units derived from ), and it was confirmed that 2.27 modifiers were introduced per molecule of the modified vinyl aromatic copolymer. did. Since the polyfunctional structural unit (e1) represented by the above formula (1) is 4.18 mol% (6.24 wt%), the initiator-derived polyfunctional structural degree (e1/c) is 0.96. there were. In formula (1), R1 is phenyl, R2 is methyl, and R3 is 2-methylbutyl. The structural unit derived from diisopropenylbenzene having a residual vinyl group contained in the modified vinyl aromatic copolymer (F-1) was 0.17 mol% (0.26 wt%). Modifier bound to isoprene-derived units was 94.2 mol%.
As a result of thermogravimetric analysis (TGA), the weight loss at 350°C (TGA ₃₅₀ ) was 0.82 wt%. A sample in which 0.5 g of modified vinyl aromatic copolymer (F-1) was dissolved in 100 g of toluene was placed in a quartz cell, and its haze (turbidity) was measured using an integrating sphere light transmittance method using toluene as a reference sample. The Haze value measured using a measuring device was 0.01.

Example 11 Synthesis of modified vinyl aromatic copolymer (G-1) 100 ml (77.9 g) of cyclohexane and 6.68 ml (46.0 mmol) of cocatalyst triethylamine were charged, and at 30°C, sec-butyllithium was added. After adding 35.38 ml of an n-hexane solution containing 2.95 g (46.0 mmol) of (the following structural formula) as a pure component,

3.10 g of DVB-960 from which impurities have been removed (the structural formulas of divinylbenzene and ethylvinylbenzene are shown below) (23.0 mmol of divinylbenzene (mixture of m-form and p-form), ethylvinylbenzene (m A solution prepared by dissolving 0.77 mmol of the component (mixture of - and p-isomers) in 90.7 ml (70.7 g) of cyclohexane was added over 2 hours. Stirring was continued for 1 hour at 30°C.

Next, 33.5 g (0.322 mol) of styrene (the following structural formula) was added over 30 minutes to start the first stage of polymerization.

The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 59°C. After the polymerization reaction was completed, a small amount of the polymerization solution was sampled and analyzed by gas chromatography (GC), and it was confirmed that no unreacted monomer was observed and the polymerization conversion rate was approximately 100%.
Next, 9.40 g (138 mmol) of isoprene (the following structural formula) was added as an additional monomer to the reactor over 30 minutes to initiate the second stage of polymerization at 30°C.

After the second stage polymerization reaction was completed, a small sample of the polymerization solution was subjected to GC analysis, and it was confirmed that no unreacted monomer was observed and the polymerization conversion rate was approximately 100%. GPC analysis revealed that the copolymer had Mn of 2610, Mw of 3260, and Mw/Mn of 1.25 at the end of the second stage of polymerization.
Next, 11.47 g (46.0 mmol) of diethylaminomethyltriethoxysilane (DEAMTES) was added as a modifier and a modification reaction was carried out for 2 hours to obtain a polymer solution containing a modified vinyl aromatic copolymer. After the polymerization reaction was completed, 10.86 g (92.0 mmol) of succinic acid as a neutralizing agent was added and stirred, followed by filtration.
Here, DEAMTES is a modifier having both an alkoxysilyl group and an amino group, as shown in the structural formula below.

When the obtained polymerization solution was concentrated by devolatilization and then dissolved in ethylcyclohexane, no formation of gel or microgel was observed. As a result, 53.12 g (yield: 96.0 wt%) of modified vinyl aromatic copolymer G-1 was obtained in terms of solid content.
Table 5 shows the analysis results of modified vinyl aromatic copolymer G-1.

The obtained modified vinyl aromatic copolymer G-1 had Mn of 2740, Mw of 4750, and Mw/Mn of 1.73. By performing GC analysis, ¹³ C-NMR and ¹ H-NMR analysis, modified vinyl aromatic copolymer G-1 contained 4.34 mol% (5.40 wt%) of structural units derived from divinylbenzene. , 0.15 mol% (0.18 wt%) of structural units derived from ethylvinylbenzene, 60.78 mol% (60.50 wt%) of structural units derived from styrene, and 26.05 mol% (60.50 wt%) of structural units derived from isoprene. Modified vinyl aromatic copolymer 1 contains mol% (16.95wt%) and 8.68 mol% (16.96wt%) of structural units derived from diethylaminomethyltriethoxysilane (DEAMTES). It was confirmed that 2.28 modifiers were introduced per molecule. Since the polyfunctional structural unit (e1) represented by the above formula (1) is 4.21 mol% (5.24 wt%), the initiator-derived polyfunctional structural degree (e1/c) is 0.97. there were. In formula (1), R1 is phenyl, R2 is hydrogen, and R3 is sec-butyl. The structural unit derived from divinylbenzene having a residual vinyl group contained in the modified vinyl aromatic copolymer (G-1) was 0.13 mol% (0.16 wt%). Modifier bound to isoprene-derived units was 95.6 mol%.
As a result of thermogravimetric analysis (TGA), the weight loss (TGA ₃₅₀ ) at 350° C. was 0.95 wt%. A sample in which 0.5 g of modified vinyl aromatic copolymer (G-1) was dissolved in 100 g of toluene was placed in a quartz cell, and its haze (turbidity) was measured using an integrating sphere light transmittance method using toluene as a reference sample. The Haze value measured using a measuring device was 0.03.

Example 12 Synthesis of modified vinyl aromatic copolymer (H-1) 220 ml (171.4 g) of cyclohexane and 6.68 ml (46.0 mmol) of co-catalyst triethylamine were charged, and sec-butyllithium was heated at 30°C. After adding 35.38 ml of an n-hexane solution containing 2.95 g (46.0 mmol) of (the following structural formula) as a pure component,

Next, 19.2 g (0.184 mol) of styrene (the following structural formula) and 12.5 g (0.184 mol) of isoprene (the following structural formula) were added over 30 minutes to initiate the first stage polymerization.

The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 56°C. After the polymerization reaction was completed, a small amount of the polymerization solution was sampled and analyzed by gas chromatography (GC), and it was confirmed that no unreacted monomer was observed and the polymerization conversion rate was approximately 100%.
Next, 9.40 g (138 mmol) of isoprene (the following structural formula) was added as an additional monomer to the reactor over 30 minutes to initiate the second stage of polymerization at 30°C.

After the second stage polymerization reaction was completed, a small sample of the polymerization solution was subjected to GC analysis, and it was confirmed that no unreacted monomer was observed and the polymerization conversion rate was approximately 100%. GPC analysis revealed that the copolymer had Mn of 2500, Mw of 3140, and Mw/Mn of 1.26 at the end of the second stage of polymerization.
Next, 11.47 g (46.0 mmol) of diethylaminomethyltriethoxysilane (DEAMTES) was added as a modifier and a modification reaction was carried out for 2 hours to obtain a polymer solution containing a modified vinyl aromatic copolymer. After the polymerization reaction was completed, 10.86 g (92.0 mmol) of succinic acid as a neutralizing agent was added and stirred, followed by filtration.
Here, DEAMTES is a modifier having both an alkoxysilyl group and an amino group, as shown in the structural formula below.

When the obtained polymerization solution was concentrated by devolatilization and then dissolved in ethylcyclohexane, no formation of gel or microgel was observed. As a result, 51.9 g (yield: 97.0 wt%) of modified vinyl aromatic copolymer H-1 was obtained in terms of solid content.
Table 5 shows the analysis results of modified vinyl aromatic copolymer H-1.

The obtained modified vinyl aromatic copolymer H-1 had Mn of 4030, Mw of 9770, and Mw/Mn of 2.43. By performing GC analysis, ¹³ C-NMR and ¹ H-NMR analysis, modified vinyl aromatic copolymer H-1 contained 3.99 mol% (5.59 wt%) of structural units derived from divinylbenzene. , 0.13 mol% (0.19 wt%) of structural units derived from ethylvinylbenzene, 31.96 mol% (35.76 wt%) of structural units derived from styrene, and 55.92 mol% (35.76 wt%) of structural units derived from isoprene. Modified vinyl aromatic copolymer 1 contains mol% (40.93 wt%) and 7.99 mol% (17.54 wt%) of structural units derived from diethylaminomethyltriethoxysilane (DEAMTES). It was confirmed that 3.46 modifiers were introduced per molecule. Since the polyfunctional structural unit (e1) represented by the above formula (1) is 3.87 mol% (5.42 wt%), the initiator-derived polyfunctional structural degree (e1/c) is 0.97. there were. In formula (1), R1 is phenyl, R2 is hydrogen, and R3 is 2-methylbutyl. The structural unit derived from divinylbenzene having a residual vinyl group contained in the modified vinyl aromatic copolymer (H-1) was 0.12 mol % (0.17 wt %). Modifier bound to isoprene-derived units was 97.8 mol%.
As a result of thermogravimetric analysis (TGA), the weight loss at 350°C (TGA ₃₅₀ ) was 0.89 wt%. A sample in which 0.5 g of modified vinyl aromatic copolymer (H-1) was dissolved in 100 g of toluene was placed in a quartz cell, and its haze (turbidity) was measured using an integrating sphere light transmittance method using toluene as a reference sample. The Haze value measured using a measuring device was 0.02.

Example 13 Synthesis of modified vinyl aromatic copolymer (I-1) 220 ml (171.4 g) of cyclohexane and 6.68 ml (46.0 mmol) of cocatalyst triethylamine were charged, and at 30°C, sec-butyllithium was added. After adding 35.38 ml of an n-hexane solution containing 2.95 g (46.0 mmol) of (the following structural formula) as a pure component,

Next, 31.34 g (0.46 mol) of isoprene (the following structural formula) was added over 60 minutes to initiate polymerization.

The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 42°C. After the polymerization reaction was completed, a small amount of the polymerization solution was sampled and analyzed by gas chromatography (GC), and it was confirmed that no unreacted monomer was observed and the polymerization conversion rate was approximately 100%. GPC analysis revealed that the copolymer had Mn of 1680, Mw of 2320, and Mw/Mn of 1.38 at the time the polymerization was completed.
Next, 11.47 g (46.0 mmol) of diethylaminomethyltriethoxysilane (DEAMTES) was added as a modifier and a modification reaction was carried out for 2 hours to obtain a polymer solution containing a modified vinyl aromatic copolymer. After the polymerization reaction was completed, 10.86 g (92.0 mmol) of succinic acid as a neutralizing agent was added and stirred, followed by filtration.
Here, DEAMTES is a modifier having both an alkoxysilyl group and an amino group, as shown in the structural formula below.

When the obtained polymerization solution was concentrated by devolatilization and then dissolved in ethylcyclohexane, no formation of gel or microgel was observed. As a result, 41.6 g (yield: 95.0 wt%) of modified vinyl aromatic copolymer I-1 was obtained in terms of solid content.
Table 5 shows the analysis results of modified vinyl aromatic copolymer I-1.

The obtained modified vinyl aromatic copolymer I-1 had Mn of 1850, Mw of 3500, and Mw/Mn of 1.90. By performing GC analysis, ¹³ C-NMR and ¹ H-NMR analysis, modified vinyl aromatic copolymer I-1 contained 4.34 mol% (6.83 wt%) of structural units derived from divinylbenzene. , 0.15 mol% (0.23 wt%) of structural units derived from ethylvinylbenzene, 86.83 mol% (71.49 wt%) of structural units derived from isoprene, and diethylaminomethyltriethoxysilane (DEAMTES). Contains 8.68 mol% (21.45 wt%) of structural units derived from . Since the polyfunctional structural unit (e1) represented by the formula (1) is 4.17 mol% (6.56 wt%), the initiator-derived polyfunctional structural degree (e1/c) is 0.96. there were. In formula (1), R1 is phenyl, R2 is hydrogen, and R3 is 2-methylbutyl. The structural unit derived from divinylbenzene having a residual vinyl group contained in the modified vinyl aromatic copolymer (H-1) was 0.17 mol % (0.27 wt %). Modifier bound to isoprene-derived units was 98.2 mol%.
As a result of thermogravimetric analysis (TGA), the weight loss at 350°C (TGA ₃₅₀ ) was 1.17 wt%. A sample in which 0.5 g of modified vinyl aromatic copolymer (H-1) was dissolved in 100 g of toluene was placed in a quartz cell, and its haze (turbidity) was measured using an integrating sphere light transmittance method using toluene as a reference sample. The Haze value measured using a measuring device was 0.04.

Example 14 Synthesis of modified vinyl aromatic copolymer (J-1) 220 ml (171.4 g) of cyclohexane and 6.68 ml (46.0 mmol) of cocatalyst triethylamine were charged, and at 30°C, sec-butyllithium was added. After adding 35.38 ml of an n-hexane solution containing 2.95 g (46.0 mmol) of (the following structural formula) as a pure component,

A solution prepared by dissolving 2.44 g (23.0 mmol) of pre-dried m-xylene (the structural formula of m-xylene is shown below) in 40.0 ml (31.2 g) of cyclohexane was added over 15 minutes. Stirring was continued for 1 hour at 30°C.

Next, 9.6 g (0.092 mol) of styrene (the following structural formula) and 18.8 g (0.276 mol) of isoprene (the following structural formula) were added over 30 minutes to initiate the first stage polymerization.

The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 58°C. After the polymerization reaction was completed, a small amount of the polymerization solution was sampled and analyzed by gas chromatography (GC), and it was confirmed that no unreacted monomer was observed and the polymerization conversion rate was approximately 100%.
Next, 9.40 g (138 mmol) of isoprene (the following structural formula) was added as an additional monomer to the reactor over 30 minutes to initiate the second stage of polymerization at 30°C.

After the second stage polymerization reaction was completed, a small sample of the polymerization solution was subjected to GC analysis, and it was confirmed that no unreacted monomer was observed and the polymerization conversion rate was approximately 100%. GPC analysis revealed that the copolymer had Mn of 1540, Mw of 2130, and Mw/Mn of 1.38 at the end of the second stage of polymerization.
Next, 11.47 g (46.0 mmol) of diethylaminomethyltriethoxysilane (DEAMTES) was added as a modifier and a modification reaction was carried out for 2 hours to obtain a polymer solution containing a modified vinyl aromatic copolymer. After the polymerization reaction was completed, 10.86 g (92.0 mmol) of succinic acid as a neutralizing agent was added and stirred, followed by filtration.
Here, DEAMTES is a modifier having both an alkoxysilyl group and an amino group, as shown in the structural formula below.

When the obtained polymerization solution was concentrated by devolatilization and then dissolved in ethylcyclohexane, no formation of gel or microgel was observed. As a result, 47.6 g (yield: 96.0 wt%) of modified vinyl aromatic copolymer J-1 was obtained in terms of solid content.
Table 5 shows the analysis results of modified vinyl aromatic copolymer J-1.

The obtained modified vinyl aromatic copolymer J-1 had Mn of 2230, Mw of 4300, and Mw/Mn of 1.93. By performing GC analysis, ¹³ C-NMR and ¹ H-NMR analysis, modified vinyl aromatic copolymer J-1 contained 4.00 mol% (4.92 wt%) of m-xylene-derived structural units. ), 16.00 mol% (19.31 wt%) of structural units derived from styrene, 72.00 mol% (56.83 wt%) of structural units derived from isoprene, and diethylaminomethyltriethoxysilane (DEAMTES). Contains 8.00 mol% (18.94 wt%) of structural units derived from . Since the polyfunctional structural unit (e1) represented by the above formula (1) is 3.92 mol% (4.82 wt%), the initiator-derived polyfunctional structural degree (e2/d) is 0.98. there were. In formula (1), R1 is phenyl, R4 is hydrogen, and R5 is hydrogen. The amount of structural units derived from m-xylene having residual methyl groups contained in the modified vinyl aromatic copolymer (J-1) was 0.08 mol% (0.10 wt%). Modifier bound to isoprene-derived units was 93.6 mol%.
As a result of thermogravimetric analysis (TGA), the weight loss at 350°C (TGA ₃₅₀ ) was 0.96 wt%. A sample in which 0.5 g of modified vinyl aromatic copolymer (H-1) was dissolved in 100 g of toluene was placed in a quartz cell, and its haze (turbidity) was measured using an integrating sphere light transmittance method using toluene as a reference sample. The Haze value measured using a measuring device was 0.04.

Table 5 shows the analysis results of the copolymers of Examples 10 to 14.

Example 15 Synthesis of modified conjugated diene copolymer (F-2) Into a nitrogen-purged autoclave reactor, 580 g of cyclohexane and 30.7 mg (0.16 mmol) of 2,2-di(2-tetrahydrofuryl)propane were added. After adding 15 g of a cyclohexane solution containing 51.2 mg (0.80 mmol) of n-butyllithium as a pure component at 50°C, 34.29 g of styrene from which impurities had been removed in advance, 1 , 3-butadiene (80.00 g) was added to initiate polymerization. The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 68°C. After the polymerization reaction was completed, 15 g of a cyclohexane solution containing 0.487 g of the modified vinyl aromatic copolymer (F-1) obtained in Example 10 was added as an SBR modifier to modify the obtained styrene-butadiene rubber (SBR). was added and a modification reaction was carried out.The modification reaction was carried out for 30 minutes at a temperature of 60°C to obtain a polymer solution.
Furthermore, 0.40 mmol of 3-glycidoxypropyltriethoxysilane (GPTES) was added and a modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.
After adding 0.045 g of 2,6-di-tert-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the modified conjugated diene-based conjugate was vacuum dried. Polymer (modified SBR) F-2 was obtained.
Table 6 shows the analysis results of modified conjugated diene copolymer F-2.

Example 16 Synthesis of modified conjugated diene copolymer (G-2) Into a nitrogen-purged autoclave reactor, 580 g of cyclohexane and 30.7 mg (0.16 mmol) of 2,2-di(2-tetrahydrofuryl)propane were added. After adding 15 g of a cyclohexane solution containing 51.2 mg (0.80 mmol) of n-butyllithium as a pure component at 50°C, 34.29 g of styrene from which impurities had been removed in advance, 1 , 3-butadiene (80.00 g) was added to initiate polymerization. The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 68°C. After the polymerization reaction was completed, 15 g of a cyclohexane solution containing 0.481 g of the modified vinyl aromatic copolymer (G-1) obtained in Example 11 was added as an SBR modifier to modify the obtained styrene-butadiene rubber (SBR). was added and a modification reaction was carried out.The modification reaction was carried out for 30 minutes at a temperature of 60°C to obtain a polymer solution.
Further, 0.40 mmol of 3-glycidoxypropyltriethoxysilane (GPTES) was added and a modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.
After adding 0.045 g of 2,6-di-tert-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the modified conjugated diene-based copolymer was dried in vacuum. Polymer (modified SBR) G-2 was obtained.
Table 6 shows the analysis results of modified conjugated diene copolymer G-2.

Example 17 Synthesis of modified conjugated diene copolymer (H-2) Into a nitrogen-purged autoclave reactor, 580 g of cyclohexane and 30.7 mg (0.16 mmol) of 2,2-di(2-tetrahydrofuryl)propane were added. After adding 15 g of a cyclohexane solution containing 51.2 mg (0.80 mmol) of n-butyllithium as a pure component at 50°C, 34.29 g of styrene from which impurities had been removed in advance, 1 , 3-butadiene (80.00 g) was added to initiate polymerization. The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 68°C. After the polymerization reaction was completed, 15 g of a cyclohexane solution containing 0.466 g of the modified vinyl aromatic copolymer (H-1) obtained in Example 12 was used as an SBR modifier to modify the obtained styrene-butadiene rubber (SBR). was added and a modification reaction was carried out.The modification reaction was carried out for 30 minutes at a temperature of 60°C to obtain a polymer solution.
Furthermore, 0.40 mmol of 3-glycidoxypropyltriethoxysilane (GPTES) was added and a modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.
After adding 0.045 g of 2,6-di-tert-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the modified conjugated diene-based conjugate was vacuum dried. Polymer (modified SBR) H-2 was obtained.
Table 6 shows the analysis results of modified conjugated diene copolymer H-2.

Example 18 Synthesis of modified conjugated diene copolymer (I-2) Into a nitrogen-purged autoclave reactor, 580 g of cyclohexane and 30.7 mg (0.16 mmol) of 2,2-di(2-tetrahydrofuryl)propane were added. After adding 15 g of a cyclohexane solution containing 51.2 mg (0.80 mmol) of n-butyllithium as a pure component at 50°C, 34.29 g of styrene from which impurities had been removed in advance, 1 , 3-butadiene (80.00 g) was added to initiate polymerization. The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 68°C. After the polymerization reaction was completed, 15 g of a cyclohexane solution containing 0.381 g of the modified vinyl aromatic copolymer (I-1) obtained in Example 13 was used as an SBR modifier to modify the obtained styrene-butadiene rubber (SBR). was added and a modification reaction was carried out.The modification reaction was carried out for 30 minutes at a temperature of 60°C to obtain a polymer solution.
Further, 0.40 mmol of 3-glycidoxypropyltriethoxysilane (GPTES) was added and a modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.
After adding 0.045 g of 2,6-di-tert-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the modified conjugated diene-based copolymer was dried in vacuum. Polymer (modified SBR) I-2 was obtained.
Table 6 shows the analysis results of modified conjugated diene copolymer I-2.

Example 19 Synthesis of modified conjugated diene copolymer (J-2) Into a nitrogen-purged autoclave reactor, 580 g of cyclohexane and 30.7 mg (0.16 mmol) of 2,2-di(2-tetrahydrofuryl)propane were added. After adding 15 g of a cyclohexane solution containing 51.2 mg (0.80 mmol) of n-butyllithium as a pure component at 50°C, 34.29 g of styrene from which impurities had been removed in advance, 1 , 3-butadiene (80.00 g) was added to initiate polymerization. The temperature of the reaction solution increased due to the heat of polymerization, and the maximum temperature reached 68°C. After the polymerization reaction was completed, 15 g of a cyclohexane solution containing 0.432 g of the modified vinyl aromatic copolymer (J-1) obtained in Example 14 was added as an SBR modifier to modify the obtained styrene-butadiene rubber (SBR). was added and a modification reaction was carried out.The modification reaction was carried out for 30 minutes at a temperature of 60°C to obtain a polymer solution.
Furthermore, 0.40 mmol of 3-glycidoxypropyltriethoxysilane (GPTES) was added and a modification reaction was carried out for 30 minutes to obtain a polymer solution containing a modified conjugated diene copolymer.
After adding 0.045 g of 2,6-di-tert-4-hydroxytoluene as an antioxidant to the obtained polymerization solution, the solvent was removed by steam stripping, and the modified conjugated diene-based conjugate was vacuum dried. Polymer (modified SBR) J-2 was obtained.
Table 6 shows the analysis results of modified conjugated diene copolymer J-2.

Example 20
The modified conjugated diene copolymer (modified SBR) F-2 obtained in Example 15, process oil, carbon black, zinc oxide, stearic acid, and anti-aging agent were blended according to the formulation shown in Table 3, and Labo Plastomil was used. The mixture was kneaded for 4 minutes at 155° C. and 60 rpm.
Sulfur and a vulcanization accelerator were added to the obtained kneaded product, and the mixture was kneaded using a Labo Plastomill at 70° C. and 60 rpm for 1 minute, followed by vulcanization to obtain a crosslinked rubber F-3.
Table 7 shows the physical properties of the obtained crosslinked rubber.

Examples 21, 22, 23, and 24
Instead of modified conjugated diene copolymer (modified SBR) F-2, modified conjugated diene copolymer (modified SBR) G-2, H- synthesized in Example 16, Examples 17, 18, and 19 Crosslinked rubbers G-3, H-3, I-3, and J-3 were obtained in the same manner as in Example 20, except that 2, I-2, and J-2 were used.
Table 7 shows the physical properties of the obtained crosslinked rubber.

According to Tables 4 and 7, the crosslinked rubber using the modified conjugated diene copolymer (modified SBR) of the example has an excellent round rubber index compared to the comparative example, and therefore has no inorganic filler. It can be seen that the material has improved dispersibility and loss during running, has excellent tensile strength and abrasion resistance, and can contribute to achieving both strength and abrasion resistance.

The modified vinyl aromatic copolymer of the present invention is particularly useful as a modifier for conjugated diene copolymers (SBR etc.). The crosslinked rubber obtained by crosslinking the obtained modified conjugated diene copolymer (modified SBR, etc.) containing a filler has excellent filler dispersibility, mechanical strength, and abrasion resistance, so it is suitable for tires (treads). It is useful as an elastomer material for seismic isolation rubber, rubber hoses, rubber rollers, footwear materials, etc.
The modified vinyl aromatic copolymer of the present invention can be used as dielectric materials, insulating materials, heat-resistant materials, structural materials, adhesives, and sealants in fields such as electrical and electronic industries, space and aircraft industries, and architecture and construction industries. It is also useful as a paint, coating agent, sealant, printing ink, dispersant, etc. The curable resin composition can be processed into films, sheets, and prepregs and used for plastic optical parts, touch panels, flat displays, film liquid crystal elements, and various optical elements such as optical waveguides and optical lenses. be. It can also be used as a modifier to modify the properties of thermoplastic resins or curable resin compositions, such as heat resistance, dielectric properties, adhesion/adhesion, and optical properties.

Claims

A polymer consisting of structural units derived from one or more monomers selected from the group consisting of a monovinyl aromatic compound (a) and a conjugated diene compound (b), wherein the polymer contains a polyfunctional vinyl aromatic compound. Contains a structural unit derived from a group compound (c) or an aromatic compound (d) having 2 to 4 alkyl groups having 1 to 3 carbon atoms, and contains a structural unit derived from component (c) or component (d). The following in which 50 mol% or more has a group R1 derived from the aromatic structure of component (c) or (d), and a group R2 or R3 derived from a component other than the aromatic structure of component (c) or (d) It is a multifunctional structural unit (e1) represented by formula (1),

Here, R1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms, R2 represents hydrogen or a hydrocarbon group having 1 to 6 carbon atoms, and R3 represents hydrogen or a hydrocarbon group having 1 to 6 carbon atoms. n represents an integer from 1 to 3. Note that Polymer indicates the main polymer structural unit derived from component (a) or component (b).
Furthermore, the terminal of the polymer is modified with at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group, and the number average molecular weight is such that the average number of functional groups per molecule is 2.0 or more. A modified vinyl aromatic copolymer having an Mn of 500 to 30,000.
When component (c) or component (d) reacts with the organic alkali metal compound, a polyfunctional structural unit (e1) represented by formula (1) is produced, and R3 is a group derived from the organic alkali metal compound. The modified vinyl aromatic copolymer according to claim 1, characterized in that:
Contains 0.5 mol% or more and 35.0 mol% or less of structural units derived from a polyfunctional vinyl aromatic compound (c) or an aromatic compound (d) having 2 to 4 alkyl groups having 1 to 3 carbon atoms. and contains 65.0 mol% or more and 99.5 mol% or less of structural units derived from one or more monomers selected from the group consisting of monovinyl aromatic compounds (a) and conjugated diene compounds (b). The modified vinyl aromatic copolymer according to claim 1, characterized in that:
The modified vinyl aromatic copolymer according to claim 1, wherein the molecular weight distribution (Mw/Mn) represented by the ratio of weight average molecular weight Mw to number average molecular weight Mn is 10.0 or less.
The modified vinyl aromatic copolymer according to claim 1, wherein the average number of functional groups per molecule is in the range of 2 to 20.
The monovinyl aromatic compound is selected from the group consisting of styrene, vinylnaphthalene, vinylbiphenyl, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, m-ethylvinylbenzene, indene and p-ethylvinylbenzene. The modified vinyl aromatic copolymer according to claim 1, which is one or more monomers.
A polyfunctional compound is produced by reacting an alkali metal compound with one or more compounds selected from a polyfunctional vinyl aromatic compound (c) or an aromatic compound having 2 to 4 alkyl groups having 1 to 3 carbon atoms (d). an initiation reaction step of producing an anionic polymerization initiator;
One or more monomers selected from the group consisting of a monovinyl aromatic compound (a) and a conjugated diene compound (b) are polymerized to form a polyfunctional structural unit (e1) represented by the above formula (1). a polymerization step to obtain a vinyl aromatic copolymer having an active end;
A functional group is formed by 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 thereof, with the active end of the vinyl aromatic copolymer. The method for producing a modified vinyl aromatic copolymer according to any one of claims 1 to 6, characterized in that it comprises a terminal modification step of forming a modified vinyl aromatic copolymer.
A modified conjugate characterized by being a reaction product of a polymer of a conjugated diene compound or a copolymer of a conjugated diene compound and an aromatic vinyl compound, and the modified vinyl aromatic copolymer according to claim 1. Diene copolymer.
0.001 to 6% by weight of the structural unit (A1) derived from the modified vinyl aromatic copolymer, 29 to 99.999% by weight of the structural unit (B1) derived from the conjugated diene compound, and the aromatic vinyl compound. The modified conjugated diene copolymer according to claim 8, containing 0 to 70% by weight of the derived structural unit (C1).
In the differential molecular weight distribution curve obtained by gel permeation chromatography (GPC) measurement, the area of the region having a number average molecular weight (Mn) three times or more of the lowest molecular weight peak, when the total area is 100%. The modified conjugated diene copolymer according to claim 78, wherein the amount is 20% or more.
At least one 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 copolymer according to any one of claims 8 to 10. A resin composition containing 0.5 to 200 parts by weight of one type of reinforcing filler.
The resin composition according to claim 11, further comprising a crosslinking agent.
A crosslinked resin product obtained by crosslinking the resin composition according to claim 12.
A structural member comprising the resin crosslinked product according to claim 13.