WO2020121745A1

WO2020121745A1 - Copolymer, method for producing copolymer, rubber composition, tire, resin composition, and resinous product

Info

Publication number: WO2020121745A1
Application number: PCT/JP2019/045163
Authority: WO
Inventors: 重永高野; オリビエタルディフ; 文堀田
Original assignee: 株式会社ブリヂストン
Priority date: 2018-12-12
Filing date: 2019-11-19
Publication date: 2020-06-18
Also published as: JPWO2020121745A1

Abstract

Provided are: an aromatic vinyl compound/conjugated diene compound copolymer which has a low glass transition temperature (Tg) while having a bonded-aromatic-vinyl-compound content and a vinyl bond content that are substantially the same as those of conventional copolymers and which satisfies a given relationship; a method for producing the copolymer; a rubber composition and a resin composition each including the copolymer; a tire obtained using the rubber composition; and a resinous product obtained using the resin composition.

Description

Copolymer, method for producing copolymer, rubber composition, tire, resin composition and resin product

The present invention relates to a copolymer, a method for producing the copolymer, a rubber composition, a tire, a resin composition and a resin product.

A copolymer of an aromatic vinyl compound such as a styrene-butadiene copolymer and a conjugated diene compound is usually synthesized by polymerization using an anionic or radical polymerization initiator, and has an isomer structure of the conjugated diene compound portion. The 1,4-structure, which is one of the above, generally includes many trans 1,4-structures (for example, Patent Document 1). Regarding the isomer structure of the conjugated diene compound part, it was difficult to control the structure other than the vinyl bond content. However, as a method for controlling the content of the cis 1,4-structure, a rare earth metallocene metal catalyst etc. A method of synthesizing a copolymer of an aromatic vinyl compound and a conjugated diene compound using a metal catalyst composed of a ligand and a metal atom, etc. has been disclosed (for example, Patent Document 2).

JP-A-1-135847 JP, 2006-137897, A

It is known that when the copolymer has various properties such as the content of the bound aromatic vinyl compound and the content of the vinyl bond within a certain range, the performance such as durability is exhibited. The copolymers described in the above Patent Documents 1 and 2 also have performances such as durability like this, but have a high glass transition temperature (Tg) of, for example, −60° C. or higher, and thus are flexible. Property becomes low, handling becomes difficult due to an increase in viscosity in a room temperature region, and when a rubber composition containing the copolymer is applied to a tire, there may arise a problem that wet braking performance is not excellent. ..

The present invention has been made in view of such a situation, and it is possible to obtain a compound having a low glass transition temperature (Tg) while maintaining the content of the bound aromatic vinyl compound and the content of the vinyl bond at the same level as those of conventional products. A polymer, a method for producing the copolymer, a rubber composition and a resin composition containing the copolymer, a tire using the rubber composition, and a resin product using the resin composition are provided. And

The present inventor, as a result of diligent study to solve the above problems, found that the invention having the following constitution can solve the above problems.

1. A copolymer of an aromatic vinyl compound and a conjugated diene compound satisfying the following relational expression.
(Relational expression) y≦0.94x−104
(In the above relation, x=Av+0.5Vi, Av is the content (% by mass) of the bound aromatic vinyl compound in the copolymer, Vi is the content (% by mass) of the vinyl bond, and y is the glass. Transition temperature (°C).)
2. A method for producing a copolymer, which comprises synthesizing a copolymer satisfying the above relational expression with an aromatic vinyl compound and a conjugated diene compound using a catalyst composition prepared by mixing predetermined catalysts A and B ..
3. A rubber composition containing the copolymer according to 1 above.
4. A tire using the rubber composition as described in 3 above.
5. A resin composition containing the copolymer according to 1 above.
6. A resin product using the resin composition described in 5 above.

According to the present invention, a copolymer having a low glass transition temperature (Tg) while maintaining the content of a bound aromatic vinyl compound and the content of a vinyl bond at the same level as conventional products, a method for producing the copolymer, A rubber composition and a resin composition containing the copolymer, a tire using the rubber composition, and a resin product using the resin composition can be provided.

Hereinafter, an embodiment of the present invention (hereinafter, may be referred to as “this embodiment”) will be described in detail. In the following description, the numerical values of the upper limit and the lower limit concerning “above”, “below”, and “to” regarding the description of the numerical range are numerical values that can be arbitrarily combined, and the numerical values in Examples are the upper limit and the lower limit. be able to.

[Copolymer]
The copolymer of the present embodiment is a copolymer of an aromatic vinyl compound and a conjugated diene compound and satisfies the following relational expression.
(Relational expression) y≦0.94x−104
(In the above relation, x=Av+0.5Vi, Av is the content (% by mass) of the bound aromatic vinyl compound in the copolymer, Vi is the content (% by mass) of the vinyl bond, and y is the glass. Transition temperature (°C).)

When the glass transition temperature (Tg) of the copolymer satisfies the above relational expression in relation to the content of the bound aromatic vinyl compound in the copolymer and the vinyl bond content, the bound aromatic vinyl compound The glass transition temperature (Tg) while maintaining the content and vinyl bond content at the same level as the conventional product and maintaining the performance such as durability (hereinafter, referred to as "maintaining the performance of the conventional product"). ) Can be a low copolymer. That is, in the conventional copolymer of the aromatic vinyl compound and the conjugated diene compound, the content of the bound aromatic vinyl compound and the vinyl bond content of the copolymer of the present embodiment are the same. However, the above relational expression could not be satisfied, and the glass transition temperature (Tg) was high. However, the copolymer of the present embodiment has the same content of the bound aromatic vinyl compound and the vinyl bond content as those of the conventional copolymer of the aromatic vinyl compound and the conjugated diene compound. The glass transition temperature (Tg) is low because the above performance is maintained and the above relational expression can be satisfied.

In the present embodiment, the low glass transition temperature (Tg) means that the glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) is −60° C. or lower, preferably −65° C. or lower, and more preferably It means −70° C. or lower, more preferably −75° C. or lower. Further, the glass transition temperature (Tg) is specifically measured using a differential scanning calorimeter, and the detailed measuring method is the method described in the examples.

X in the above relational expression is preferably 5 or more, more preferably 7 or more, further preferably 10 or more, still more preferably 15 or more, and the upper limit is preferably 40 or less, more preferably 35 or less, further preferably 30. It is below. When x is in the above range, a lower glass transition temperature (Tg) is easily obtained while maintaining the performance of the conventional product.

The y in the above relational expression, that is, the glass transition temperature (Tg) of the copolymer of the present embodiment is as described above, and the lower the lower, the more preferable, -60°C or lower, and more preferably -65°C or lower, The temperature is more preferably −70° C. or lower, further preferably −75° C. or lower, and the lower limit is not particularly limited, but is usually −105° C. or higher. When the glass transition temperature (Tg) is within the above range, handling (hereinafter, also referred to as “workability”) is improved due to an increase in viscosity in a room temperature region.

In the copolymer of the present embodiment, the aromatic vinyl compound preferably has 8 to 10 carbon atoms. Examples of the aromatic vinyl compound include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, o-ethylstyrene, m-ethylstyrene and p-ethylstyrene. .. The aromatic vinyl compound may be a single compound or a combination of two or more compounds. The aromatic vinyl compound as a monomer of the copolymer preferably contains styrene, and more preferably consists only of styrene, from the viewpoint of maintaining and further improving the performance of conventional products. That is, the aromatic vinyl compound unit in the copolymer preferably contains a styrene unit, and more preferably consists of only a styrene unit. Further, when such an aromatic vinyl compound unit is combined with other units, the performance of the conventional product is maintained and the glass transition temperature (Tg) is easily lowered.

In the copolymer of the present embodiment, the conjugated diene compound preferably has 4 to 8 carbon atoms, and specific examples of the conjugated diene compound include 1,3-butadiene, isoprene and 1,3. -Pentadiene, 2,3-dimethyl-1,3-butadiene and the like. The conjugated diene compound may be a single compound or a combination of two or more compounds. The conjugated diene compound as a monomer of the copolymer preferably contains at least one selected from 1,3-butadiene and isoprene from the viewpoint of effectively maintaining and further improving the performance of conventional products. More preferably, it consists of at least one selected from 3,3-butadiene and isoprene, and even more preferably consists only of isoprene. That is, the conjugated diene compound unit in the copolymer preferably contains at least one kind selected from a 1,3-butadiene unit and an isoprene unit, and consists of at least one kind selected from a 1,3-butadiene unit and an isoprene unit. Is more preferable, and it is even more preferable that the unit consists of isoprene units only. Further, when such a conjugated diene compound unit is combined with other units, the performance of the conventional product is maintained and the glass transition temperature (Tg) tends to be lowered.

The copolymer of the present embodiment has the following properties, for example, so that the above relational expression is easily satisfied, that is, a lower glass transition temperature (Tg) is easily obtained while maintaining the performance of the conventional product. ..
Preferred properties of the copolymer of the present embodiment include the content of a bonded aromatic vinyl compound, the content of a vinyl bond, an aromatic vinyl single chain to all bonded aromatic vinyl compounds, and 8 or more aromatic vinyl units in series. The ratio of the long chain of the aromatic vinyl compound may be mentioned.

The content of the bound aromatic vinyl compound is preferably 3% by mass or more, more preferably 5% by mass or more, further preferably 10% by mass or more, still more preferably 15% by mass or more, and the upper limit is preferably It is 40 mass% or less, more preferably 35 mass% or less, and further preferably 30 mass% or less. Here, the content of the bound aromatic vinyl compound is obtained from the integral ratio of the peaks of the H-NMR spectrum. The detailed measuring method is the method described in Examples.
The vinyl bond content is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 1% by mass or more, and the upper limit is preferably 15% by mass or less, more preferably 10% by mass. Hereafter, it is more preferably 5% by mass or less. The vinyl bond content can be measured by an infrared method (Morero method).

The ratio of the above aromatic vinyl single chain is preferably 90% by mass or more, more preferably 95% by mass or more, and further preferably 98% by mass or more. The ratio of the long chain of the aromatic vinyl compound is preferably less than 10% by mass, more preferably 5% by mass or less, and further preferably 2% by mass or less. Here, the chain distribution of the aromatic vinyl compound is measured by a combined method of nuclear magnetic resonance spectrum and gel permeation chromatography (GPC), and the number of aromatic vinyl compound units in the aromatic vinyl compound chain part is It can be measured by the GPC method after decomposing the sample copolymer with ozone.

The properties that the copolymer of the present embodiment preferably has also include the content of cis-1,4 bonds in the conjugated diene compound unit. Specifically, the cis-1,4-bond content is preferably 75% or more, more preferably 85% or more, even more preferably 95% or more, and the upper limit is preferably 99% or less.

The polystyrene equivalent weight average molecular weight (Mw) of the copolymer of the present embodiment is preferably 10,000 to 10,000,000, more preferably 100,000 to 5,000,000, and further preferably 150,000. ~1,000,000. The polystyrene equivalent number average molecular weight (Mn) of the copolymer is preferably 10,000 to 10,000,000, more preferably 30,000 to 5,000,000, and further preferably 50,000 to 1,000. 1,000. The molecular weight distribution [Mw/Mn (weight average molecular weight/number average molecular weight)] of the copolymer is preferably 1.00 to 3.50, more preferably 1.25 to 3.00, and further preferably 1. It is 50 to 2.50.
When the upper limits of Mw and Mn of the copolymer are within the above ranges, excellent workability of the copolymer can be obtained. When the molecular weight distribution of the copolymer is 3.50 or less, sufficient homogeneity of the physical properties of the copolymer can be obtained.
Here, the weight average molecular weight (Mw), the number average molecular weight (Mn), and the molecular weight distribution (Mw/Mn) can be determined by gel permeation chromatography (GPC) using polystyrene as a standard substance. These detailed measuring methods are the methods described in the examples.

The copolymer of this embodiment may be modified or unmodified.

The method for producing the copolymer of the present embodiment is not particularly limited as long as it is synthesized by using the aromatic vinyl compound and the conjugated diene compound described above and satisfies the above relational expression, but each of the above properties is easily described. In order to satisfy the above relational expression, it is preferable that the copolymer is produced by the method for producing a copolymer of the present embodiment described later.

[Method for producing copolymer]
The method for producing the copolymer of the present embodiment uses a catalyst composition in which the following catalyst A and catalyst B are mixed, and an aromatic vinyl compound and a conjugated diene compound satisfy the above relational expressions. It is characterized in that a polymer is synthesized.
In the method for producing the copolymer of the present embodiment, the aromatic vinyl compound, the conjugated diene compound and the relational formula are as described above. The catalyst composition used in the method for producing the copolymer of the present embodiment will be described in detail below.

(Catalyst composition)
The catalyst composition used in the method for producing the copolymer of the present embodiment is a mixture of catalyst A and catalyst B. By using a catalyst composition containing the catalyst A and the catalyst B, a high catalytic activity can be obtained in the synthesis, and the obtained copolymer has a cis-1,4 bond content in the conjugated diene compound unit. Can be improved, and it becomes easy to satisfy the above relational expression.

(Catalyst A)
The catalyst A used in the production method of the present embodiment is a rare earth element compound represented by the following general formula (a-1).
M-(AQ ¹ )(AQ ² )(AQ ³ ) (a-1)

In the general formula (a-1), M is scandium, yttrium or a lanthanoid element, AQ ¹ , AQ ² and AQ ³ are functional groups which may be the same or different, and A is nitrogen, oxygen. Or sulfur, which is a functional group having at least one MA bond. As the catalyst A, one represented by the general formula (a-1) may be used alone, or two or more may be used in combination.

Specifically, the lanthanoid element of M is lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. As M, a lanthanoid element is preferable, and gadolinium is particularly preferable, from the viewpoint of enhancing the catalytic activity and reaction controllability and making it easier for the resulting copolymer to satisfy the above relational expression.

When A is nitrogen, examples of the functional group represented by AQ ¹ , AQ ² and AQ ³ (that is, NQ ¹ , NQ ² and NQ ³ ) include an amide group and the like. Examples of the amide group include an aliphatic amide group such as a dimethylamide group, a diethylamide group and a diisopropylamide group; a phenylamide group, a 2,6-di-tert-butylphenylamide group, a 2,6-diisopropylphenylamide group, 2,6-Dineobenzylphenylamide group, 2-tert-butyl-6-isopropylphenylamide group, 2-tert-butyl-6-neobentylphenylamide group, 2-isopropyl-6-neobentylphenyl Examples thereof include amide groups, arylamide groups such as 2,4,6-tert-butylphenylamide group; and bistrialkylsilylamide groups such as bistrimethylsilylamide group. A trimethylsilylamide group is preferred. The above functional groups may be used alone or in combination of two or more.

When A is oxygen, the general formula (a-1) is represented by M-(OQ ¹ )(OQ ² )(OQ ³ ), and such a rare earth element compound is not particularly limited, but, for example, The following formula (aI):
(RO) ₃ M (aI)
A rare earth alcoholate represented by the following formula (a-II):
(R-CO ₂ ) ₃ M (a-II)
And a rare earth carboxylate represented by Here, in each of the following formulas (a-I) and (a-II), R is an alkyl group having 1 to 10 carbon atoms, which may be the same or different.

When A is sulfur, the general formula (a-1) is represented by M-(SQ ¹ )(SQ ² )(SQ ³ ), and such a rare earth element compound is not particularly limited. The following formula (a-III):
(RS) ₃ M (a-III)
A rare earth alkyl thiolate represented by the following formula (a-IV):
(R-CS ₂ ) ₃ M (a-IV)
And the like. Here, in each formula of the following compounds (a-III) and (a-IV), R is an alkyl group having 1 to 10 carbon atoms, which may be the same or different.

(Catalyst B)
The catalyst B used in the production method of the present embodiment is a cyclopentadiene skeleton-containing compound selected from substituted or unsubstituted cyclopentadiene, substituted or unsubstituted indene, and substituted or unsubstituted fluorene. As the catalyst B, one kind among these may be used alone, or two or more kinds may be used in combination.

The compound having a cyclopentadiene skeleton is preferably substituted cyclopentadiene, substituted indene or substituted fluorene, and more preferably substituted indene. By using such a compound, the bulkiness as a polymerization catalyst is advantageously increased, so that the reaction time can be shortened and the reaction temperature can be raised. Moreover, since the compound having a cyclopentadiene skeleton has many conjugated electrons, the catalytic activity in the reaction system can be further improved.

Examples of the substituted cyclopentadiene include pentamethylcyclopentadiene, tetramethylcyclopentadiene, isopropylcyclopentadiene, trimethylsilyl-tetramethylcyclopentadiene and the like.

Examples of the substituted indene include 2-phenyl-1H-indene, 3-benzyl-1H-indene, 3-methyl-2-phenyl-1H-indene, 3-benzyl-2-phenyl-1H-indene and 1-benzyl. -1H-indene and the like are mentioned, and among them, 3-benzyl-1H-indene and 1-benzyl-1H-indene are preferable from the viewpoint of narrowing the molecular weight distribution.

Further, examples of the substituted fluorene include trimethylsilylfluorene and isopropylfluorene.

The amount of the cyclopentadiene skeleton-containing compound used in catalyst B is preferably 0.1 to 10 times mol, more preferably 0.5 to 5 times mol, and still more preferably 0.75 to 1. It is 5 times mol, and even more preferably about 1 times mol.

In the present embodiment, the catalyst composition is a mixture of the catalyst A and the catalyst B, and the catalyst composition may include the catalyst A, the catalyst B, and the reaction product of the catalyst A and the catalyst B. By containing the reaction product of catalyst A and catalyst B, a high catalytic activity is obtained during the synthesis, and the copolymer obtained is improved in the cis-1,4 bond content in the conjugated diene compound unit. It is possible to easily satisfy the above relational expression. In the present embodiment, the catalyst composition may contain the residues of the catalyst A and the catalyst B that did not contribute to the reaction between the catalyst A and the catalyst B, but the catalyst composition is efficiently obtained. From the viewpoint, it is preferable that the residual amounts of the catalyst A and the catalyst B are small.

(Other catalysts)
In the production method of the present embodiment, in the catalyst composition, in addition to the catalyst A and the catalyst B, the cis-1,4 bond content in the conjugated diene compound unit is improved to satisfy the above relational expression. From the viewpoint of facilitating, at least one selected from the following catalyst C, catalyst D and catalyst E can be preferably added as another catalyst. That is, in the production method of the present embodiment, it is preferable that the catalyst composition further comprises at least one selected from catalyst C, catalyst D and catalyst E. By blending at least one selected from catalyst C, catalyst D and catalyst E, the catalyst composition is selected from the reaction product of catalyst A and catalyst B as well as the reaction product and catalysts C to E. At least one reactant, at least two reactants selected from catalysts A to E, and the like, which may contain the remaining single catalysts A to E that did not contribute to these reactants Becomes

In the present embodiment, after the catalyst A and the catalyst B are blended, at least one selected from the other catalysts C to E may be blended, or the catalyst A and the catalyst B and the catalyst C to the catalyst may be blended. At least one selected from E may be blended at the same time, but from the viewpoint of improving the cis-1,4 bond content in the conjugated diene compound unit to easily satisfy the above relational expression, After obtaining a reaction product of catalyst A and catalyst B, it is preferable to use a catalyst composition in which the reaction product and the other catalysts C to E are blended.
Hereinafter, the catalysts C, D and E that are preferably used will be described.

(Catalyst C)
The catalyst C preferably used in the production method of the present embodiment is an ionic compound.
Examples of the ionic compound include ionic compounds composed of a non-coordinating anion and a cation, which can react with the rare earth element compound of the catalyst A to form a cationic transition metal compound. ..
Here, examples of the non-coordinating anion include tetraphenylborate, tetrakis(monofluorophenyl)borate, tetrakis(difluorophenyl)borate, tetrakis(trifluorophenyl)borate, tetrakis(tetrafluorophenyl)borate, tetrakis( Pentafluorophenyl)borate, tetrakis(tetrafluoromethylphenyl)borate, tetra(tolyl)borate, tetra(xylyl)borate, (triphenyl, pentafluorophenyl)borate, [tris(pentafluorophenyl),phenyl]borate, tri Decahydride-7,8-dicarbaundecaborate and the like can be mentioned.

Examples of the cation include a carbonium cation, an oxonium cation, an ammonium cation, a phosphonium cation, a cycloheptatrienyl cation, and a ferrocenium cation having a transition metal.
Specific examples of the carbonium cation include tri-substituted carbonium cations such as triphenylcarbonium cation and tri(substituted phenyl)carbonium cation, and more specifically, as tri(substituted phenyl)carbonium cation, , Tri(methylphenyl)carbonium cation, tri(dimethylphenyl)carbonium cation, and the like.

Specific examples of ammonium cations include trialkylammonium cations such as trimethylammonium cation, triethylammonium cation, tripropylammonium cation, tributylammonium cation (eg, tri(n-butyl)ammonium cation); N,N-dimethylanilinium. Cation, N,N-diethylanilinium cation, N,N-dialkylanilinium cation such as N,N-2,4,6-pentamethylanilinium cation; dialkylammonium cation such as diisopropylammonium cation, dicyclohexylammonium cation, etc. Is mentioned.
Specific examples of the phosphonium cation include triarylphosphonium cations such as triphenylphosphonium cation, tri(methylphenyl)phosphonium cation, and tri(dimethylphenyl)phosphonium cation.

The ionic compound is preferably a compound selected from the above non-coordinating anion and cation and combined, and specifically, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, triphenylcarbonium. Tetrakis(pentafluorophenyl)borate and the like are preferable. In addition, these ionic compounds may be used alone or in combination of two or more.
The amount of the ionic compound used in the catalyst C is preferably 0.01 to 10 times mol, more preferably 0.1 to 3 times mol, and further preferably 0.3 to 1 times mol with respect to the catalyst A.

(Catalyst D)
The catalyst D preferably used in the production method of the present embodiment is an organometallic compound represented by the following general formula (d-1).
YR ¹ _a R ² _b R ³ _c (d-1)

In the general formula (d-1), Y is a metal element selected from the elements of Group 1, Group 2, Group 12 and Group 13 of the periodic table, and R ¹ and R ² have 1 to 10 carbon atoms. 10 is a hydrocarbon group or a hydrogen atom, R ³ is a hydrocarbon group having 1 to 10 carbon atoms, R ¹ , R ² and R ³ may be the same or different from each other, and Y is When it is a metal element of Group 1 of the periodic table, a is 1 and b and c are 0, and when Y is a metal element of Group 2 or 12 of the periodic table, , A and b are 1 and c is 0, and when Y is a metal element of Group 13 of the periodic table, a, b and c are 1.

Among the organometallic compounds represented by the general formula (d-1), the organoaluminum compound represented by the following general formula (dI) is preferable.
AlR ¹ R ² R ³ (dI)
In the general formula (dI), R ¹ and R ² are hydrocarbon groups having 1 to 10 carbon atoms or hydrogen atoms, R ³ is a hydrocarbon group having 1 to 10 carbon atoms, and R ¹ and R ^{2 are} And R ³ may be the same or different from each other. That is, in the organoaluminum compound represented by the general formula (dI), in the general formula (d-1), Y is an aluminum element, and R ¹ and R ² are hydrocarbons having 1 to 10 carbon atoms. R ³ is a group or a hydrogen atom, R ³ is a hydrocarbon group having 1 to 10 carbon atoms, and a, b and c are 1.

Examples of the organoaluminum compound represented by the general formula (dI) include trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-t- Butyl aluminum, tripentyl aluminum, trihexyl aluminum, tricyclohexyl aluminum, trioctyl aluminum; diethyl aluminum hydride, di-n-propyl aluminum hydride, di-n-butyl aluminum hydride, diisobutyl aluminum hydride, dihexyl hydride Aluminum, diisohexyl aluminum hydride, dioctyl aluminum hydride, diisooctyl aluminum hydride; ethyl aluminum dihydride, n-propyl aluminum dihydride, isobutyl aluminum dihydride and the like can be mentioned. Among them, triethyl aluminum, triisobutyl aluminum, diethyl aluminum hydride and diisobutyl aluminum hydride are preferable.

These organometallic compounds may be used alone or in combination of two or more.
The amount of the organometallic compound used as the catalyst D is preferably 1 to 50 times mol, more preferably 3 to 15 times mol, and further preferably 5 to 10 times mol, with respect to the catalyst A.

(Catalyst E)
The catalyst E preferably used in the production method of the present embodiment is a halogen compound.
Examples of the halogen compound include a Lewis acid, a complex compound of a metal halide and a Lewis base, an organic compound containing an active halogen, and these Lewis acids, a complex compound of a metal halide and a Lewis base, an organic compound containing an active halogen. One kind selected from compounds can be used. By reacting the catalyst E with the rare earth element compound of the catalyst A, a cationic transition metal compound, a halogenated transition metal compound, or a compound having a transition metal center with insufficient charge can be produced. The 1,4 bond content can be improved to facilitate the satisfaction of the above relational expression.

As the Lewis acid of the halogen compound, a boron-containing halogen compound such as B(C ₆ F ₅ ) _{3 and} an aluminum-containing halogen compound such as Al(C ₆ F ₅ ) ₃ can be used, and the third compound in the periodic table can be used. It is also possible to use a halogen compound containing an element belonging to Group 4, Group 5, Group 5, Group 6, or Group 8. Preferably, an aluminum halide or an organic metal halide is used. Further, chlorine or bromine is preferable as the halogen element.
Specific examples of such a Lewis acid include methylaluminum dibromide, methylaluminum dichloride, ethylaluminum dibromide, ethylaluminum dichloride, butylaluminum dibromide, butylaluminum dichloride, dimethylaluminum bromide, dimethylaluminum chloride and diethylaluminum. Bromide, diethyl aluminum chloride, dibutyl aluminum bromide, dibutyl aluminum chloride, methyl aluminum sesquibromide, methyl aluminum sesquichloride, ethyl aluminum sesquibromide, ethyl aluminum sesquichloride, dibutyltin dichloride, aluminum tribromide, antimony trichloride, antimony pentachloride, Examples thereof include phosphorus trichloride, phosphorus pentachloride, tin tetrachloride, titanium tetrachloride, and tungsten hexachloride. Among them, diethyl aluminum chloride, ethyl aluminum sesquichloride, ethyl aluminum dichloride, diethyl aluminum bromide, ethyl aluminum sesquibromide and ethyl aluminum dibromide are preferable.

Examples of the metal halide forming the complex compound of the metal halide of the halogen compound and the Lewis base include beryllium chloride, beryllium bromide, beryllium iodide, magnesium chloride, magnesium bromide, magnesium iodide, calcium chloride, bromide. Calcium, calcium iodide, barium chloride, barium bromide, barium iodide, zinc chloride, zinc bromide, zinc iodide, cadmium chloride, cadmium bromide, cadmium iodide, mercury chloride, mercury bromide, mercury iodide, Manganese chloride, manganese bromide, manganese iodide, rhenium chloride, rhenium bromide, rhenium iodide, copper chloride, copper bromide, copper iodide, silver chloride, silver bromide, silver iodide, gold chloride, gold iodide , Gold bromide and the like. Among these, magnesium chloride, calcium chloride, barium chloride, manganese chloride, zinc chloride and copper chloride are preferable, and magnesium chloride, manganese chloride, zinc chloride and copper chloride are more preferable.

As the Lewis base constituting the complex compound of the metal halide and the Lewis base, a phosphorus compound, a carbonyl compound, a nitrogen compound, an ether compound, an alcohol and the like are preferable. Specifically, tributyl phosphate, tri-2-ethylhexyl phosphate, triphenyl phosphate, tricresyl phosphate, triethylphosphine, tributylphosphine, triphenylphosphine, diethylphosphinoethane, diphenylphosphinoethane, acetylacetone, benzoylacetone , Propionitrile acetone, valeryl acetone, ethyl acetylacetone, methyl acetoacetate, ethyl acetoacetate, phenyl acetoacetate, dimethyl malonate, diethyl malonate, diphenyl malonate, acetic acid, octanoic acid, 2-ethylhexanoic acid, oleic acid , Stearic acid, benzoic acid, naphthenic acid, versatic acid, triethylamine, N,N-dimethylacetamide, tetrahydrofuran, diphenyl ether, 2-ethylhexyl alcohol, oleyl alcohol, stearyl alcohol, phenol, benzyl alcohol, 1-decanol, lauryl alcohol, etc. Can be mentioned. Among these, tri-2-ethylhexyl phosphate, tricresyl phosphate, acetylacetone, 2-ethylhexanoic acid, versatic acid, 2-ethylhexyl alcohol, 1-decanol, and lauryl alcohol are preferable.
The Lewis base is usually reacted in a proportion of 0.01 to 30 mol, preferably 0.5 to 10 mol, per 1 mol of metal halide. When the reaction product with the Lewis base is used, the amount of metal remaining in the copolymer obtained by the synthesis can be reduced.

Also, examples of the organic compound containing active halogen of the above halogen compound include benzyl chloride.

These halogen compounds may be used alone or in combination of two or more.
The amount of the halogen compound used in the catalyst E is preferably 1 to 5 times mol that of the catalyst A.

(Synthesis of aromatic vinyl compound and conjugated diene compound)
In the method for producing the copolymer of the present embodiment, the synthesis of the aromatic vinyl compound and the conjugated diene compound may be carried out according to a conventional method except that the above catalyst composition is used, and there is no particular limitation. For example, the synthesis of the aromatic vinyl compound and the conjugated diene compound may be performed through a polymerization step, and if necessary, a coupling step, a washing step, and other steps.

(Polymerization process)
As the polymerization method in the polymerization step, any method such as a solution polymerization method, a suspension polymerization method, a liquid phase bulk polymerization method, an emulsion polymerization method, a gas phase polymerization method or a solid phase polymerization method can be used. When a solvent is used in the polymerization reaction, such a solvent may be one that is inactive in the polymerization reaction, and examples thereof include toluene, cyclohexane, and normal hexane.

The above-mentioned polymerization step may be carried out in one stage or in multiple stages of two or more stages. The one-step polymerization process is a process in which all kinds of monomers to be polymerized, that is, an aromatic vinyl compound and a conjugated diene compound are reacted simultaneously to polymerize. In addition, the multi-stage polymerization process is one or more stages in which a part of the compound to be used is first reacted to form a polymer (first polymerization stage), and then the remaining compound is added and polymerized ( In this step, the second to final polymerization steps are carried out for polymerization.

In the presence of the catalyst composition, since the reactivity of the conjugated diene compound is higher than that of the aromatic vinyl compound, the ratio of the aromatic vinyl single chain is controlled by controlling the order of addition of the conjugated diene compound and the dropping rate, Bond content (cis-1,4 bond content) in the entire unit derived from the conjugated diene compound in the produced multi-component copolymer, content of the unit derived from the compound (that is, aromatic vinyl compound and conjugated diene compound It is possible to control the copolymerization ratio).
In the method for producing the copolymer of the present embodiment, the content of the aromatic vinyl single chain is increased and the content of the cis-1,4 bond is increased to obtain the copolymer, and the above relation is satisfied. From the viewpoint of easily satisfying the formula, it is preferable to synthesize the aromatic vinyl compound by dropping a conjugated diene compound.

In the method for producing the copolymer of the present embodiment, the polymerization step is preferably performed in an atmosphere of an inert gas, preferably nitrogen gas or argon gas.
The polymerization temperature in the polymerization step is not particularly limited, but may be, for example, in the range of −100 to 200° C., and may be about room temperature. From the viewpoint of increasing the reaction rate and improving the cis-1,4 selectivity of the polymerization reaction, it is preferably -50 to 175°C, more preferably 0 to 150°C, and further preferably 50 to 100°C.
The pressure in the polymerization step is preferably in the range of 0.1 to 10.0 MPa in order to sufficiently incorporate the non-conjugated olefin compound into the polymerization reaction system.

The reaction time of the polymerization step is not particularly limited, but is, for example, in the range of 1 second to 10 days, and the desired microstructure of the obtained copolymer, the type of each monomer, the input amount and the addition order, the catalyst It can be appropriately selected depending on the conditions such as the type and polymerization temperature. From the viewpoint of improving the proportion of aromatic vinyl single chains and the bond content (cis-1,4 bond content) in the entire unit derived from the conjugated diene compound in the produced multicomponent copolymer, the reaction time is preferably 30. Minutes to 5 days, more preferably 1 hour to 3 days, still more preferably 2 hours to 40 hours.

For example, when a conjugated diene compound is supplied dropwise to an aromatic vinyl compound, the conjugated diene compound is dissolved in a solvent such as cyclohexane and is usually 5 to 45% by mass, preferably 15 to 30% by mass, When the solution is added dropwise at a dropping rate of usually 0.1 to 5.0 mL/min, preferably 0.3 to 3.0 mL/min, the properties of the obtained copolymer are stabilized, and cis-1, in the conjugated diene compound unit, The 4-bond content can be improved, and it becomes easy to satisfy the above relational expression.
Further, in the polymerization step, the polymerization may be stopped by using a polymerization terminator such as methanol, ethanol or isopropanol.

(Coupling process)
A coupling step may be performed in the method for producing the copolymer of the present embodiment. From the viewpoint of maintaining the performance of conventional products and easily lowering the glass transition temperature (Tg), it is preferable that the copolymer obtained is unmodified. Therefore, in the production method of the present embodiment, the coupling The process may not be performed.

The coupling step is a step of performing a reaction for modifying at least a part of the polymer chain end of the copolymer obtained by the above-mentioned polymerization step. In the coupling step, it is preferable to perform the coupling reaction when the polymerization reaction reaches 100%.
The coupling agent used in the coupling reaction is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include tin-containing compounds such as bis(-1-octadecyl maleate dioctyltin); 4,4′ An isocyanate compound such as diphenylmethane diisocyanate; an alkoxysilane compound such as glycidylpropyltrimethoxysilane. These may be used alone or in combination of two or more. Among these, bis(1-octadecyl maleate-1-octadecyl)dioctyltin is preferable in terms of reaction efficiency and low gel formation.

(Washing process)
The washing step is a step of washing the copolymer obtained in the polymerization step. By this washing step, the amount of catalyst residue in the copolymer can be suitably reduced.
The medium used for washing is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include methanol, ethanol and isopropanol. When a catalyst derived from a Lewis acid is used as a polymerization catalyst, an acid (for example, hydrochloric acid, sulfuric acid, nitric acid) can be added to these solvents before use. The amount of acid added is preferably 15 mol% or less based on the solvent. If it is more than this, the acid may remain in the copolymer, which may adversely affect the reaction during kneading and vulcanization.

[Rubber composition]
The rubber composition of the present embodiment contains the above-mentioned copolymer of the present embodiment. The rubber composition of the present embodiment may include, for example, a rubber component and additives as other components in addition to the copolymer of the present embodiment.

Examples of rubber components that can be used in combination with the copolymer of the present embodiment include high-purity natural rubber, epoxidized natural rubber, hydroxylated natural rubber, hydrogenated natural rubber, and grafted natural rubber, in addition to RSS and TSR. Natural rubber such as modified natural rubber (NR), butadiene rubber (BR), styrene butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber, ethylene-propylene rubber (EPM), ethylene-propylene- Other rubber components such as non-conjugated diene rubber (EPDM), polysulfide rubber, silicone rubber, fluororubber and urethane rubber may be contained. These rubber components may be used alone or in combination of two or more.

(Modification of rubber component)
The rubber component may be unmodified or modified.
The modified functional group in the case of being modified is not particularly limited as long as it is a functional group having an affinity for the filler (particularly silica), and is composed of a nitrogen atom, a silicon atom, an oxygen atom, and a tin atom. It preferably comprises at least one atom selected from the group.
Examples thereof include a modified functional group containing a nitrogen atom, a modified functional group containing a silicon atom, a modified functional group containing an oxygen atom, and a modified functional group containing a tin atom. A modified functional group containing, a modified functional group containing a silicon atom, and a modified functional group containing an oxygen atom are preferable. The modification with these modifying functional groups may be carried out with one kind of modifying functional group alone, or with two or more kinds of modifying functional groups.

The content of the copolymer with respect to the total amount of the above-mentioned copolymer and other rubber components in the rubber composition may be appropriately selected depending on the properties such as desired durability and is not particularly limited, but the efficiency From the viewpoint of obtaining properties such as excellent durability, it is preferably 15% by mass or more, more preferably 20% by mass or more, and the upper limit is preferably 100% by mass or less, more preferably 90% by mass or less.

(filler)
The filler is not particularly limited, and for example, a reinforcing filler that reinforces the rubber composition can be used. Examples of the reinforcing filler include, in addition to silica, white fillers such as aluminum hydroxide and calcium carbonate; carbon black and the like are preferable, and silica and carbon black are more preferable.
As the filler, only silica may be used alone, or both silica and carbon black may be used.

The carbon black is not particularly limited and can be appropriately selected according to the purpose. The carbon black is, for example, preferably FEF, SRF, HAF, ISAF or SAF grade, more preferably HAF, ISAF or SAF grade.

The type of silica is not particularly limited. For example, wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, general grade silica such as aluminum silicate, surface treatment with a silane coupling agent, etc. It can be used depending on the application such as applied special silica.

(Other ingredients)
In the rubber composition used in the present embodiment, if necessary, for example, an antioxidant, a cross-linking agent (including a vulcanizing agent such as sulfur), a cross-linking accelerator (in a range that does not impair the effects of the present invention, Vulcanization accelerator), crosslinking accelerator (vulcanization accelerator), zinc white (ZnO), softener, wax, antioxidant, foaming agent, plasticizer, lubricant, tackifier, petroleum resin, ultraviolet ray Ingredients such as an absorbent, a dispersant, a compatibilizer and a homogenizer can be appropriately contained.

(Production of rubber composition)
The rubber composition of the present embodiment can be produced by kneading the above components using a kneading machine such as a Banbury mixer, a roll, or an internal mixer. Here, upon blending and kneading, all components may be blended and kneaded at once, or each component may be blended and kneaded in multiple stages such as two stages or three stages. In addition, at the time of kneading, a kneading machine such as a roll, an internal mixer, or a Banbury rotor can be used. Further, when molding the rubber composition into a sheet shape, a belt shape or the like, a known molding machine such as an extrusion molding machine or a press machine can be used.

The rubber composition used in this embodiment may be produced by crosslinking. The crosslinking conditions are not particularly limited, and usually a temperature of 140 to 180° C. and a time of 5 to 120 minutes can be adopted.

Since the rubber composition of the present embodiment contains a copolymer having a low glass transition temperature (Tg) while maintaining the performance of the conventional product, the rubber composition of the present embodiment has excellent performance on ice, as well as performance of the conventional product such as durability. It is expected that it will also have performance such as wet brake performance. Therefore, the rubber composition of the present embodiment is suitable for rubber products such as a conveyor belt, a rubber crawler, a hose, a vibration isolation device, a vibration isolation rubber used for a seismic isolation device, and a seismic isolation rubber in addition to the tires described below. Used.

[tire]
The tire of the present embodiment uses the rubber composition of the present embodiment described above. Since such a tire uses the rubber composition of the present embodiment, it has not only the performance of conventional products such as durability but also excellent performance on ice, wet braking performance and the like.
The application site of the rubber composition of the present embodiment in the tire is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a tread, a base tread, a sidewall, a side reinforcing rubber and a bead filler. Be done. In addition to the performance of conventional products such as the excellent durability of the rubber composition of the present embodiment, from the viewpoint of effectively utilizing the characteristics of having excellent performance on ice, performance such as wet braking performance, the tread is preferable as the application site. Especially, a tread of a studless tire is preferable.

As a method of manufacturing the tire of this embodiment, a conventional method can be used. For example, a carcass layer, a belt layer, a tread layer, and the like, which are made of an unvulcanized rubber composition and/or cord of the present embodiment, are sequentially laminated on a tire molding drum, and the drum is removed. Leave and use green tires. Then, a desired tire (for example, a pneumatic tire) can be manufactured by heating and vulcanizing this green tire according to a conventional method.

[Resin composition and resin product]
The resin composition of this embodiment contains the above-mentioned copolymer of this embodiment. By combining the copolymer and the other resin component, various properties such as durability originally possessed by the other resin component are improved. Moreover, the resin product of this embodiment uses the resin composition of this embodiment.

The resin component to be combined with the copolymer is not particularly limited and various resin components can be adopted, and may be appropriately selected according to the performance desired for the resin product.
Examples of such resin components include homopolymers of polyethylene, polypropylene, polybutene, polystyrene, etc., ethylene-propylene copolymers, ethylene-methacrylic acid copolymers, ethylene-ethyl acrylate copolymers, ethylene-propylene-diene. Terpolymers, copolymers such as ethylene-vinyl acetate copolymers, and polyolefin resins such as ionomer resins thereof, vinyl alcohol homopolymers, polyvinyl alcohol resins such as ethylene-vinyl alcohol copolymers, poly( (Meth)acrylic acid resin and its ester resin, polyamide resin such as aliphatic polyamide resin and aromatic polyamide resin, polyethylene glycol resin, carboxyvinyl copolymer, styrene-maleic acid copolymer, vinylpyrrolidone homopolymer, vinylpyrrolidone -Polyvinylpyrrolidone resin such as vinyl acetate copolymer, polyester resin, cellulose resin, mercaptomethanol, hydrogenated styrene-butadiene, syndiotactic polybutadiene, trans polyisoprene, trans polybutadiene and the like can be mentioned.

In the resin composition of the present embodiment, the content of the copolymer with respect to all the resin components may be appropriately adjusted depending on other resins to be combined, desired properties, etc., and is usually about 1 to 99% by mass, preferably 5 It is up to 90% by mass.

Further, the resin composition of the present embodiment may contain various additives depending on desired performance. As various additives, the additives usually contained in the resin composition can be used without particular limitation, for example, UV absorbers, weathering agents such as light stabilizers, antioxidants, filling that may be contained in the rubber composition. Examples of the agent include fillers, softeners, colorants, flame retardants, plasticizers, antistatic agents and the like.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

(Analysis of copolymer)
The number average molecular weight (Mn), the weight average molecular weight (Mw), the molecular weight distribution (Mw/Mn), the glass transition temperature (Tg), the content of the bound aromatic vinyl compound, and the vinyl bond content of the multi-component copolymer are The measurement method was as follows.

(1) Number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn)
Monodisperse polystyrene was analyzed by gel permeation chromatography [GPC: Tosoh HLC-8121GPC/HT, column: Tosoh GMH _HR -H(S)HT x 2, detector: differential refractometer (RI)]. As a standard, the polystyrene-equivalent number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw/Mn) of the copolymer were determined. The measurement temperature is 40°C.
(2) Glass transition temperature (Tg)
The glass transition temperature (Tg) of the copolymer was measured using a differential scanning calorimeter (DSC, manufactured by TA Instruments Japan Co., Ltd., "DSCQ2000") in accordance with JIS K 7121-1987.
(3) Content of bound aromatic vinyl compound The content Av (mass %) of the bound aromatic vinyl compound in the copolymer is determined by the peak of ¹ H-NMR spectrum (100° C., d-tetrachloroethane standard: 6 ppm). It was calculated from the integral ratio of.
(4) Vinyl bond content The vinyl bond content Vi (mass %) was determined by the infrared method (Morero method).

(Example 1: Synthesis of copolymer 1)
91 g of styrene which is an aromatic vinyl compound and 30 g of cyclohexane were added to a sufficiently dried 2000 mL pressure-resistant stainless steel reactor.
Mono(bis(1,3-tert-butyldimethylsilyl)indenyl)bis(bis(dimethylsilyl)amide gadolinium complex (1,3-[(t-Bu)) was placed in a glass container in a glove box under a nitrogen atmosphere. _{_{_{_{Me 2 Si] 2 C 9 H}}}} 5 Gd [N (SiHMe 2) 2] 2) 0.224mmol, trityl tetrakis (pentafluorophenyl) borate _{_{_{_{(Ph 2 CB (C 6 F}}}} 5) 4) 0.150mmol, and hydrogen 1.7 mmol of diisobutylaluminum chloride was charged, and 73 mL of cyclohexane was added to prepare a catalyst solution.
The obtained catalyst solution was added to the pressure-resistant stainless steel reactor and heated to 70°C.
Next, 318 g of a cyclohexane solution containing 75 g of 1,3-butadiene of the conjugated diene compound was continuously added dropwise to the pressure-resistant stainless steel reactor at a rate of 1.4 to 1.7 mL/min, and the synthesis temperature was 70° C. A copolymer was obtained by synthesizing in 292 minutes.
Then, 1 ml of an isopropanol solution containing 5% by mass of 2,2′-methylene-bis(4-ethyl-6-t-butylphenol) (NS-5) was added to the pressure-resistant stainless steel reactor to stop the reaction. Then, the copolymer was separated using a large amount of methanol and dried in vacuum at 50° C. to obtain a copolymer 1.

Regarding the obtained copolymer 1, the number average molecular weight (Mn), the weight average molecular weight (Mw), the molecular weight distribution (Mw/Mn), the glass transition temperature (Tg), and the content of the bound aromatic vinyl compound are obtained by the above method. The amount and vinyl bond content were measured. The measurement results are shown in Table 1.

(Example 2: Synthesis of copolymer 2)
An aromatic vinyl compound was prepared in the same manner as in Example 1 except that the cyclohexane solution containing 1,3-butadiene was added dropwise at a rate of 1.0 to 1.5 mL/min and the synthesis time was 369 minutes. Of styrene and 1,3-butadiene as a conjugated diene compound were synthesized to prepare a copolymer 2. Regarding the obtained copolymer 2, the number average molecular weight (Mn), the weight average molecular weight (Mw), the molecular weight distribution (Mw/Mn), the glass transition temperature (Tg), and the content of the bound aromatic vinyl compound are obtained by the above method. The amount and vinyl bond content were measured. The measurement results are shown in Table 1.

(Example 3: Synthesis of copolymer 3)
In Example 1, the amount of cyclohexane supplied to the pressure-resistant stainless steel reactor was 30 g to 328 g, the amount of cyclohexane used for the catalyst solution was 73 mL to 40 mL, and the dropping rate of the cyclohexane solution containing 1,3-butadiene was 1.0. A copolymer of styrene, an aromatic vinyl compound, and 1,3-butadiene, a conjugated diene compound, was synthesized in the same manner as in Example 1 except that the synthesis time was 400 mL for 1.5 mL/min. 3 was synthesized. Regarding the obtained copolymer 3, the number average molecular weight (Mn), the weight average molecular weight (Mw), the molecular weight distribution (Mw/Mn), the glass transition temperature (Tg), and the content of the bound aromatic vinyl compound are obtained by the above method. The amount and vinyl bond content were measured. The measurement results are shown in Table 1.

(Example 4: Synthesis of copolymer 4)
In Example 1, the amount of styrene supplied to the pressure-resistant stainless steel reactor was 91 g to 136 g, the amount of cyclohexane was 30 g to 730 g, the amount of cyclohexane used in the catalyst solution was 73 mL to 40 mL, and a cyclohexane solution containing 1,3-butadiene was used. Of styrene as an aromatic vinyl compound and 1,3-butadiene as a conjugated diene compound in the same manner as in Example 1 except that the dropping rate was 0.7 to 1.3 mL/min and the synthesis time was 488 minutes. Synthesis was carried out to synthesize copolymer 4. Regarding the obtained copolymer 4, the number average molecular weight (Mn), the weight average molecular weight (Mw), the molecular weight distribution (Mw/Mn), the glass transition temperature (Tg), and the content of the bound aromatic vinyl compound are obtained by the above method. The amount and vinyl bond content were measured. The measurement results are shown in Table 1.

(Example 5: Synthesis of copolymer 5)
In Example 1, the amount of styrene supplied to the pressure-resistant stainless steel reactor was 91 g to 136 g, the amount of cyclohexane was 30 g to 730 g, the amount of cyclohexane used in the catalyst solution was 73 mL to 40 mL, and a cyclohexane solution containing 1,3-butadiene was used. Was added in the same manner as in Example 1 except that the dropping rate was 0.7 to 1.3 mL/min, the synthesis temperature was 90° C., and the synthesis time was 505 minutes. , 3-Butadiene was synthesized to prepare a copolymer 5. Regarding the obtained copolymer 5, the number average molecular weight (Mn), the weight average molecular weight (Mw), the molecular weight distribution (Mw/Mn), the glass transition temperature (Tg), and the content of the bound aromatic vinyl compound are obtained by the above method. The amount and vinyl bond content were measured. The measurement results are shown in Table 1.

(Example 6: Synthesis of copolymer 6)
In Example 1, the amount of styrene supplied to the pressure-resistant stainless steel reactor was 91 g to 136 g, the amount of cyclohexane was 30 g to 564 g, diisobutylaluminum hydride was triisobutylaluminum 2.2 mmol, and the amount of cyclohexane used in the catalyst solution was 73 mL. To 90 mL, the dropping rate of the cyclohexane solution containing 1,3-butadiene was 0.4 to 1.0 mL/min, the synthesis temperature was 90° C., and the synthesis time was 666 minutes. Copolymer 6 was synthesized by synthesizing styrene which is an aromatic vinyl compound and 1,3-butadiene which is a conjugated diene compound. Regarding the obtained copolymer 6, the number average molecular weight (Mn), the weight average molecular weight (Mw), the molecular weight distribution (Mw/Mn), the glass transition temperature (Tg), and the content of the bound aromatic vinyl compound are obtained by the above method. The amount and vinyl bond content were measured. The measurement results are shown in Table 1.

The copolymers shown in Table 1 are as follows.
*Copolymers 1 to 6: The copolymers obtained in Examples 1 to 6 above.
*#1500: Emulsion polymerization SBR#1500 (manufactured by JSR)
*#0202: SBR#0202 (made by JSR)

From Table 1, the copolymers 1 to 6 of Examples 1 to 6 satisfy the relational expression y≦0.94x−104, and the aromatic compounds of the copolymers of Comparative Examples 1 and 2 of the conventional products are bonded. It was confirmed that the glass transition temperature (Tg) was as low as −60° C. or lower while being equal to the vinyl compound content and the vinyl bond content. On the other hand, the copolymers of Comparative Examples 1 and 2 did not satisfy the above relational expression, and the glass transition temperature (Tg) was as high as −60° C. or higher.
From the above results, the copolymer of the present embodiment has the content of the bound aromatic vinyl compound and the content of the vinyl bond which are comparable to those of the conventional product, and has a lower glass transition temperature (Tg). From the above, it can be said that, for example, when the copolymer is used as a rubber composition in a tire, a tire having excellent on-ice performance and wet brake performance as well as durability of conventional products can be obtained.

According to the present invention, the glass transition temperature (Tg) is low while maintaining the content of the bound aromatic vinyl compound and the vinyl bond content at the same level as the conventional product, that is, while maintaining the performance of the conventional product, Provided are a copolymer having a low glass transition temperature (Tg), a rubber composition and a resin composition containing the copolymer, a tire using the rubber composition, and a resin product using the resin composition. be able to. Since the rubber composition of the present embodiment contains the copolymer of the present embodiment, while maintaining the performance of conventional products such as durability, it also has a lower glass transition temperature (Tg). In addition, it is preferably used for conveyor belts, rubber crawlers, hoses, and rubber products such as anti-vibration rubber and anti-vibration rubber used in anti-vibration devices and anti-vibration devices.

Claims

A copolymer of an aromatic vinyl compound and a conjugated diene compound satisfying the following relational expression.
(Relational expression) y≦0.94x−104
(In the above relation, x=Av+0.5Vi, Av is the content (% by mass) of the bound aromatic vinyl compound in the copolymer, Vi is the content (% by mass) of the vinyl bond, and y is the glass. Transition temperature (°C).)
The copolymer according to claim 1, wherein the ratio of the long chain of the aromatic vinyl compound in which 8 or more aromatic vinyl units are connected to all the bonded aromatic vinyl compounds in the unit of the aromatic vinyl compound is less than 10% by mass.
The copolymer according to claim 1 or 2, wherein the content of cis-1,4-bond in the unit of the conjugated diene compound is 75% or more and 99% or less.
The copolymer according to any one of claims 1 to 3, wherein x is 5 or more and 40 or less in the relational expression.
The copolymer according to any one of claims 1 to 4, wherein y is -105°C or higher and -75°C or lower in the above relational expression.
The copolymer according to any one of claims 1 to 5, wherein the aromatic vinyl compound is styrene.
The copolymer according to any one of claims 1 to 6, wherein the conjugated diene compound is at least one selected from butadiene and isoprene.
A method for producing a copolymer, which comprises synthesizing a copolymer satisfying the following relational expression with an aromatic vinyl compound and a conjugated diene compound using a catalyst composition obtained by mixing the following catalyst A and catalyst B: ..
(Catalyst A) A rare earth element compound represented by the following general formula (a-1).
M-(AQ 1 )(AQ 2 )(AQ 3 ) (a-1)
(In the general formula (a-1), M is scandium, yttrium or a lanthanoid element, AQ 1 , AQ 2 and AQ 3 are functional groups which may be the same or different, A is nitrogen, It is oxygen or sulfur and is a functional group having at least one MA bond.)
(Catalyst B) A cyclopentadiene skeleton-containing compound selected from a substituted or unsubstituted cyclopentadiene, a substituted or unsubstituted indene, and a substituted or unsubstituted fluorene.
(Relational expression) y≦0.94x−104
(In the above relation, x=Av+0.5Vi, Av is the content (% by mass) of the aromatic vinyl compound, Vi is the content (% by mass) of the vinyl bond, and y is the glass transition temperature (° C.). is there.)
The method for producing a copolymer according to claim 8, wherein the catalyst composition further contains the following catalyst C.
(Catalyst C) Ionic compound
The method for producing a copolymer according to claim 8 or 9, wherein the catalyst composition further contains the following catalyst D.
(Catalyst D) An organometallic compound represented by the following general formula (d-1).
YR 1 a R 2 b R 3 c (d-1)
(In the general formula (d-1), Y is a metal element selected from the elements of Group 1, Group 2, Group 12 and Group 13 of the periodic table, and R 1 and R 2 have 1 carbon atoms. To R 10 are hydrocarbon groups or hydrogen atoms, R 3 is a hydrocarbon group having 1 to 10 carbon atoms, R 1 , R 2 and R 3 may be the same or different from each other, and Y Is a metal element of Group 1 of the periodic table, a is 1 and b and c are 0, and Y is a metal element of Group 2 or 12 of the periodic table. Is a and b are 1 and c is 0, and a, b and c are 1 when Y is a metal element of Group 13 of the periodic table.)
The method for producing a copolymer according to any one of claims 8 to 10, wherein the catalyst composition further contains the following catalyst E.
(Catalyst E) halogen compound
A rubber composition containing the copolymer according to any one of claims 1 to 7.
A tire using the rubber composition according to claim 12.
A resin composition containing the copolymer according to any one of claims 1 to 7.
A resin product using the resin composition according to claim 14.