JP2000086857A - Conjugated diene rubber composition containing crystalline segment containing reinforcement - Google Patents

Abstract

(57) [Problem] To provide a rubber composition having excellent low-temperature rebound resilience and tensile stress, and having sufficient flex fatigue resistance and a wear index. SOLUTION: (i) (A) a conjugated diene-based polymer segment 10 having a high cis content of 40% or more;
A partially crystalline block copolymer rubber comprising 98% by weight and (B) 90 to 2% by weight of a crystalline segment, having a molecular weight distribution of 4 or less and a weight average molecular weight in terms of polystyrene of 20,000 to 10,000. A conjugated diene-based rubber composition containing a crystalline segment, comprising: a block copolymer rubber of 1,000,000 and (ii) a reinforcing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel rubber composition containing a conjugated diene block copolymer rubber containing a crystalline segment and a reinforcing agent.

[0002]

2. Description of the Related Art The following techniques are disclosed in a method for producing polybutadiene having a cis content of 35% or more. JP-A-61-85414 discloses a 1,2-vinyl bond 7
５０50%, cis-1,4 bond> 50%, trans-1,
A method for making a polybutadiene rubber with 4 bonds <5% is disclosed. Japanese Patent Application Laid-Open No. 9-316118 discloses a method for producing an amorphous random copolymer by copolymerizing an olefin and butadiene. The random copolymer has a lower Tg than the high cis-butadiene rubber.
Due to the high g, the improvement of the wear characteristics is not sufficient, and since it is amorphous, the improvement of the processing characteristics is not sufficient.

On the other hand, JP-A-57-15415 and JP-A-59-164313 disclose methods for producing reinforcing polybutadiene. The polymer is polybutadiene having a boiling n-hexane insoluble content of 5 to 30%, and cis-
Polybutadiene with high 1,4 bonds was produced, followed by 1,4
2. Polybutadiene obtained by a method of performing polymerization. JP-A-5-194658 discloses a polybutadiene rubber composition containing 10 to 25% by weight of n-hexane insoluble matter. As is evident in this,
There is a description that syndiotactic polybutadiene and 1,4-cis polybutadiene may be separately polymerized and these products may be blended. The polybutadiene obtained by the production method and the composition thereof are different from each other in two kinds of rubbers. Is a blended rubber composition.

However, it is common general knowledge in the art that blends of different rubbers are mostly incompatible and that there is an interface between the two polymers, reducing their reinforcing properties.

On the other hand, a polybutadiene rubber having a high cis content can obtain only a crosslinked product having a small tensile stress even when reinforcing particles such as carbon black are blended. In addition, there are also problems such as large bagging and swell in processing characteristics.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rubber composition having excellent low-temperature rebound resilience and tensile stress and having sufficient flex fatigue resistance and a wear index.

[0007]

Means for Solving the Problems In order to solve the above problems, the present inventors have made intensive studies and as a result, have found that a new conjugated diene polymer segment having a high cis content and a crystalline segment such as ethylene are obtained. It has been found that the problem can be solved by using a copolymer having the same.

That is, the present invention relates to (i) 10 to 98% by weight of a conjugated diene polymer segment having a high cis content (A) of 40% or more and (B) 90 to 2% by weight of a crystalline segment. % Of a partially crystalline block copolymer rubber having a molecular weight distribution of 4 or less and a weight average molecular weight in terms of polystyrene of 20,000 to 10,000.
A conjugated diene-based rubber composition containing a crystalline segment, comprising 2 to 90 parts by weight of a block copolymer rubber having a molecular weight of 000 and (ii) a reinforcing agent.

[(I) Partially crystalline block copolymer rubber] In the partially crystalline block copolymer (i) of the present invention, the weight ratio of the conjugated diene segment to the crystalline segment is usually 10 conjugated diene segments. ~ 98
% By weight, and 90 to 2% by weight of a crystalline segment, preferably 50 to 98% by weight of a conjugated diene segment and 50 to 2% by weight of a crystalline segment, and more preferably 70 to 96% by weight of a conjugated diene segment. 30 to 4% by weight. If the crystal part is too small, the processing characteristics are not good, and if it is too large, the strength characteristics are not good.

The molecular weight distribution [weight average molecular weight (Mw) / number average molecular weight (Mn)] of the partially crystalline block copolymer (i) of the present invention is preferably 1.1 or more and 4 or less, preferably. Is 1.2 to 3 or less, more preferably 1.3 to 2 or less. If the molecular weight distribution is too narrow, processability is poor, and if the distribution is too wide, heat build-up is poor.

If the weight average molecular weight of the partially crystalline block copolymer (i) of the present invention is too small, the tensile strength is poor, and if it is too large, the processability is poor. 000 to 10,000
It is necessary to be 0,000, preferably 50,
000-5,000,000, more preferably 10
It is from 2,000 to 2,500,000.

In the partially crystalline block copolymer (i) of the present invention, if the cis content in the polybutadiene segment is excessively low, the abrasion characteristics deteriorate, which is not desirable. It is necessary that the content be at least 40% by weight or more. , Preferably at least 50% by weight, more preferably at least 70% by weight.

In the block copolymerization method, a conjugated diene polymer block (A) may be prepared first, and then a monomer forming a crystalline segment (B) may be block-copolymerized. The monomer to be formed may be separately polymerized, and the polymerization terminal of the conjugated diene polymer segment (A) may be reacted with the polymerization terminal of the crystalline segment (B) or a reactive portion in the molecular chain. Alternatively, a reaction starting point may be formed in the molecular chain of the conjugated diene polymer segment (A) by an organometallic catalyst, and a monomer serving as a component of the crystalline segment (B) may be graft-copolymerized.

[Regarding the high cis content conjugated diene polymer segment (A)]
The conjugated diene polymer segment which is a segment can be produced as follows. That is, (a) a carbonyl group,
A transition metal compound belonging to Group IV of the periodic table having a cyclopentadienyl skeleton having a substituent having at least one atomic group selected from a sulfonyl group, an ether group and a thioether group; (ii) an aluminoxane; ) An ionic compound capable of producing a cationic transition metal compound by reacting with the transition metal compound (a), (iii) a Lewis acid compound capable of producing a cationic transition metal compound by reacting with the transition metal compound (a), Or (iv) Periodic Tables I-III
A conjugated diene monomer, or conjugated in the presence of a catalyst obtained by contacting at least one cocatalyst selected from an organometallic compound of a main group element metal under conditions satisfying the following formulas α and β: It can be produced by polymerizing a diene monomer and a monomer copolymerizable therewith.

Formula α-100 <T <80 Formula β 0.017 <t <6000exp (−0.0921T) T is the contact temperature (° C.), t is the contact time (min.) The polymer rubber (i) is copolymerizable for forming the crystalline segment (B) by utilizing the living property of the active terminal of the conjugated diene polymer segment (A) obtained as described above. It can be obtained by block copolymerization by adding a monomer.

Group IV transition of the Periodic Table having a cyclopentadienyl skeleton having a substituent having at least one atomic group selected from the carbonyl group, sulfonyl group, ether group and thioether group as the component (a). The metal compound is preferably a compound represented by the following general formula (1) or general formula (2). General formula (1)

Embedded image (Wherein, M is a transition metal of Group IV of the periodic table, X ¹ , X ² , X ³
Is a group independently selected from the group consisting of a hydrogen atom, a halogen, a hydrocarbon group having 1 to 12 carbon atoms and a hydrocarbon oxy group having 1 to 12 carbon atoms, and Y is a hydrogen atom or a carbon atom having 1 carbon atom. To 20 hydrocarbon groups which may themselves form a ring with a cyclopentadienyl group, wherein Z ¹ and Z ² are each a hydrogen atom and a hydrocarbon group having 1 to 12 carbon atoms. A is an independently selected group, wherein A is an oxygen atom or a sulfur atom, R ¹ is a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, a hydrocarbonoxy group having 1 to 12 carbon atoms, or a 12 hydrocarbon sulfide groups, and n is an integer of 0 to 5. ) General formula (2)

Embedded image (Wherein, M is a transition metal of Group IV of the periodic table, X ¹ , X ² , X ³
Is a group independently selected from the group consisting of a hydrogen atom, a halogen, a hydrocarbon group having 1 to 12 carbon atoms and a hydrocarbon oxy group having 1 to 12 carbon atoms, and Y is a hydrogen atom or a carbon atom having 1 carbon atom. To 20 hydrocarbon groups which may themselves form a ring with a cyclopentadienyl group, wherein Z ¹ and Z ² are each a hydrogen atom and a hydrocarbon group having 1 to 12 carbon atoms. A is an independently selected group, A is an oxygen atom or a sulfur atom, R ² is a hydrocarbon group having 1 to 12 carbon atoms, and n is an integer of 0 to 5. )

The transition metal compound represented by the general formula (1) or (2) is more preferably a cyclopentadienyl group; a cyclopentadienyl group having a substituent such as an alkyl, aryl or cycloalkyl group. A so-called metallocene compound having a dienyl group or a plurality of condensed cyclic substituents as a ligand, and the cyclopentadienyl group of the ligand has a structure of> C = O structure,> C = S structure, -C-
The substituent has at least one atomic group selected from the group consisting of an OC— structure and a —CS—C— structure. Further, a transition metal of Group IV of the periodic table (M in the formula) is
Preferably Ti, Zr or Hf, more preferably Ti
It is. Desirable X ¹ , X ² and X ³ are preferably a chlorine atom as a halogen, an alkyl group such as methyl and neopentyl as a hydrocarbon group, an aralkyl group such as benzyl, and a hydrocarbonoxy group such as methoxy, ethoxy and isopropoxy. And aralkyloxy groups such as an alkoxy group and a benzyloxy group. Particularly, an alkoxy group as a hydrocarbonoxy group is preferred. In Y, for example,
Hydrogen atom, methyl, ethyl, propyl, isopropyl,
In addition to an alkyl group such as butyl and t-butyl, an aryl group such as phenyl, an aralkyl group such as benzyl, and the like, a hydrocarbon group containing a silicon atom such as a trimethylsilyl group is also included. Y bonded to the cyclopentadienyl ring is
Together with this cyclopentadienyl ring, a polycyclic group such as an indenyl group and a fluorenyl group may be formed. As Z ¹ and Z ² , for example, a hydrogen atom, methyl,
Examples include an alkyl group such as ethyl, propyl, isopropyl, butyl, and t-butyl, an aryl group such as phenyl, and an aralkyl group such as benzyl. As R ¹ , for example, a hydrogen atom, a hydrocarbon group, an alkyl group such as methyl, ethyl, propyl, isopropyl, butyl, t-butyl, an aryl group such as phenyl, an aralkyl group such as benzyl, and a hydrocarbonoxy group Alkoxy groups such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, t-butoxy, aryloxy groups such as phenyloxy groups, aralkyloxy groups such as benzyloxy groups, and hydrocarbonthio groups such as methylthio, ethylthio, propylthio, and isopropylthio ,
Examples thereof include an alkyl sulfide group such as butylthio and t-butylthio, an aryl sulfide group such as a phenylthio group, and an aralkyl sulfide group such as a benzyl thio group. As R ¹ , a hydrocarbon oxy group is preferable, and among them, an alkoxy group is particularly preferable. Examples of R ² include hydrocarbon groups such as alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl and t-butyl, aryl groups such as phenyl, and aralkyl groups such as benzyl. n is preferably 1 or 2, more preferably 1.

Specific examples of the transition metal compound of Group IV of the periodic table (a) include those represented by the general formula (1):
MeO (CO) CH ₂ CpTiCl ₃ , MeO (CO) C
H (Me) CpTiCl ₃ , {3- [MeO (CO) C
H ₂ ]｝ (1-Me) CpTiCl ₃ , and those included in the general formula (2) include MeOCH ₂ CH ₂ CpTiCl ₃
(Me in the formula represents a methyl group, and Cp represents a cyclopentadienyl structure).

The method for preparing the Group IV transition metal compound of the periodic table represented by the general formula (1) or (2) is not particularly limited. For example, in the case of MeO (CO) CH ₂ CpTiCl ₃ , Macromol. Symposia, 1997,
Vol. 118, pages 55-60, based on the description of MeOC.
In the case of H ₂ CH ₂ CpTiCl ₃ , see JP-A-9-77818.
It may be prepared based on the description in Japanese Patent Application Publication No.

Group IV transition metal compound of the periodic table (a)
The aluminoxane used in combination with is a linear or cyclic polymer represented by the following general formula (3), and is an organic aluminum oxy compound.

Embedded image [—Al (R ³ ) O—] n (3) (R ³ is a hydrocarbon group having 1 to 10 carbon atoms, and specific examples thereof include methyl, ethyl, propyl, and isobutyl. R ³ may be substituted with a halogen atom and / or an R ⁴ O group, and R ⁴ is a hydrocarbon group having 1 to 10 carbon atoms. , Specific examples of which include methyl, ethyl,
Examples include an alkyl group such as propyl and isobutyl, and among them, a methyl group is preferable. n is a degree of polymerization, 5 or more;
It is preferably at least 10, and the upper limit is not particularly limited, but is preferably at most 100, more preferably at most 50. )

The ionic compound for forming the cationic complex by reacting with the transition metal compound (a) to obtain the component (b) includes an anion of tetrakis (pentafluorophenyl) borate and, for example, (CH) _{3) 2} N
Amine cation having an active proton such as (C ₆ H ₅ ) H ⁺ , trisubstituted carbonium cation such as (C ₆ H ₅ ) ₃ C ⁺ , carborane cation, metal carborane cation, ferrocenium having a transition metal An ionic compound with a cation can be used.

The conjugated diene polymer segment (A)
In order to obtain the catalyst component, a metal hydride compound, an organometallic compound of a main element metal of Groups I to III of the periodic table, an organometallic halogen compound, an organometallic hydride compound, or the like may be used in combination. . Examples of the metal hydride compound include, for example, NaH, LiH, CaH ₂ , LiAlH ₄ , NaBH
_{4 and the} like. Examples of the organometallic compound of the main element metal include methyllithium, butyllithium, phenyllithium, dibutylmagnesium, trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, and trioctylaluminum. As the organometallic halogen compound, for example, ethyl magnesium chloride,
Butylmagnesium chloride, dimethylaluminum chloride, diethylaluminum chloride, sesquiethylaluminum chloride, ethylaluminum dichloride and the like. As the hydrogenated organometallic compound, for example, diethyl aluminum hydride,
Sesquiethyl aluminum hydride and the like can be mentioned.

In order to obtain the conjugated diene polymer segment (A), the transition metal compound and / or ionic compound can be used by being supported on a carrier. Examples of the carrier include an inorganic compound and an organic polymer compound. As the inorganic compound, inorganic oxides, inorganic chlorides, inorganic hydroxides and the like are preferable, and a small amount of carbonate,
Those containing sulfate may be used. Particularly preferred are inorganic oxides, specific examples of which include silica, alumina,
Magnesia, titania, zirconia, calcia and the like can be mentioned. These inorganic oxides are preferably porous fine particles having an average particle diameter of 5 to 150 μm and a specific surface area of ² to 800 m ² / g, and can be used after being heat-treated at 100 to 800 ° C., for example. The organic polymer compound preferably has an aromatic ring, a substituted aromatic ring, or a functional group such as a hydroxy group, a carboxyl group, an ester group, or a halogen atom in a side chain. Specific examples of the organic polymer compound include ethylene, propylene, an α-olefin homopolymer having a functional group introduced by chemical modification such as polybutene, an α-olefin copolymer, acrylic acid, methacrylic acid, vinyl chloride, Examples include homopolymers and copolymers of vinyl alcohol, styrene, divinylbenzene, and the like, and further, chemically modified products thereof.
These organic polymer compounds have an average particle size of 5 to 250.
μm spherical fine particles are used. By supporting the transition metal compound and / or the ionic compound, contamination due to adhesion of the catalyst to the polymerization reactor can be prevented.

The conjugated diene monomer for forming the conjugated diene polymer segment (A) of the present invention includes:
1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, 1,
3-hexadiene and the like are included. Among the conjugated dienes, 1,3-butadiene and 2-methyl-1,3-butadiene are preferred, and 1,3-butadiene is more preferred. These conjugated diene monomers can be used alone or in combination of two or more.
-It is preferred to use butadiene alone.

The monomers which can be copolymerized with the conjugated diene monomer to form the conjugated diene polymer segment (A) include styrene, o-methylstyrene, p-methylstyrene, m -Methylstyrene,
2,4-dimethylstyrene, ethylstyrene, p-te
rt-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-bromostyrene, 2-methyl-1,4-dichlorostyrene , 2,4-
Dibromostyrene, aromatic vinyl such as vinylnaphthalene, ethylene, propylene, olefins such as 1-butene, cyclopentene, dicyclopentadiene, 2-norbornene, cyclic olefins such as 5-ethylidene-2-norbornene, 1,5-hexadiene, Non-conjugated dienes such as 1,6-heptadiene and 1,7-octadiene;
Methyl (meth) acrylate, (meth) acrylonitrile, (meth) acrylamide and the like are included.

In the production of the conjugated diene polymer segment (A) of the present invention, the transition metal compound (a) and the aluminoxane and / or the ionic compound (b) are used.
The conjugated diene monomer or the conjugated diene monomer and a monomer copolymerizable therewith are polymerized in the presence of a catalyst which has been brought into contact with (aged in advance). Not only can the polymerization activity and initiator efficiency be improved, but also the molecular weight distribution of the resulting polymer can be further narrowed. Specifically, aging and polymerization are performed by the following methods (1) to (7), and each component is preferably a solution (1) or (5) to (7), and (1) is preferably a solution. Most preferred.

(1) After the component solution (a) and the component solution (b) are brought into contact in advance, polymerization is carried out by bringing the solution into contact with a monomer. (2) After the component solution (a) and the component slurry (b) are brought into contact in advance, polymerization is carried out by bringing the component solution into contact with the monomer. (3) After the component (a) component slurry and the component solution (b) are brought into contact in advance, polymerization is carried out by further contacting with the monomer. (4) After the component slurry (a) and the component slurry (b) are brought into contact in advance, polymerization is carried out by further contacting with a monomer. (5) bringing the (a) component solution into contact with the (b) component solution;
After further contact with the carrier, the generated supported catalyst is separated, and the supported catalyst is brought into contact with the monomer to carry out polymerization. (6) After bringing the component solution and the carrier into contact, the component (b) is further brought into contact with the component solution to separate the generated supported catalyst, and the supported catalyst is brought into contact with the monomer to carry out polymerization. (7) After bringing the component solution and the carrier into contact with each other, the component (a) is further brought into contact with the component solution, the generated supported catalyst is separated, and the supported catalyst is brought into contact with the monomer to carry out polymerization.

The component (a) and the component (b) can be used in the form of either a solution or a slurry, respectively, but are preferably in the form of a solution in order to obtain a higher polymerization activity. Solvents used for preparing solutions or slurries include hydrocarbon solvents such as butane, pentane, hexane, heptane, octane, cyclohexane, mineral oil, benzene, toluene, xylene, and halogens such as chloroform, methylene chloride, dichloroethane, and chlorobenzene. It is a chlorinated hydrocarbon solvent. Preferred solvents are aromatic hydrocarbons such as toluene and benzene.

The contact temperature of component (a) with component (b) (T,
C) is from -100 to 80C, preferably from -80 to 70C. The contact time (t, min.) Is 0.017 <t <6.
000 exp (−0.0921 T), and 0.083 <t <4000 exp (−0.092 T).
1T), more preferably 0.17 <t <
It is particularly preferable to satisfy 2000 exp (-0.0921T). At a high temperature of 80 ° C. or higher, the desired aging effect cannot be obtained, and at a low temperature of −100 ° C. or lower, there is a disadvantage in economy. t> 6000exp (-0.0921T)
The desired aging effect cannot be obtained with the aging time of, and the aging time of 0.017> t makes it difficult to perform a practical operation.

The amount of the catalyst used for forming the conjugated diene polymer segment (A) in the present invention is usually in the range of 100 parts per mole of the monomer.
-0.01 mmol, preferably 10-0.1 mmol, more preferably 5-0.2 mmol.
The polymerization reaction when a specific polymerization temperature is applied is a so-called living polymerization system. Therefore, the molecular weight of the resulting polymer can be regulated by the ratio of the transition metal compound to the monomer. The amount of the transition metal compound (a) per 1 mol of the monomer is particularly preferably 5 to 0.2 mmol per mol of the monomer to obtain a polymer which is preferable as a rubber material. Then, with this amount of catalyst used, a polymer having a particularly narrow molecular weight distribution can be obtained.

The molar ratio of aluminoxane / transition metal compound in component (b) is usually from 10 to 10,000, preferably from 100 to 5,000, and the molar ratio of ionic compound / transition metal compound is usually from 0.01 to 100. , Preferably 0.1 to 10. Furthermore, when the organometallic compound is shared, the molar ratio of the organometallic compound / transition metal compound is usually 0.1 to 10,000, preferably 1 to 1,000.
It is.

In the present invention, the polymerization of the conjugated diene monomer for forming the conjugated diene-based polymer segment (A), or the conjugated diene monomer and a monomer copolymerizable therewith, is carried out by using an inert hydrocarbon. In addition to a solution polymerization method in a system solvent, a slurry polymerization method, and a bulk polymerization method using a monomer as a diluent, a gas phase polymerization method in a gas phase stirring tank or a gas phase fluidized bed can also be employed. Among these methods, the solution polymerization method is preferable in terms of maintaining living polymerizability and producing a polymer having a narrow molecular weight distribution. The polymerization temperature is -100 to 100C, preferably -80 to 80C, more preferably -60C to 60C.
It is. The temperature is preferably lower from the viewpoint of advancing living polymerization and the production of a polymer having a narrow molecular weight distribution by increasing the rate of the initiation reaction for the growth reaction. On the other hand, it is not preferable to use an extremely low temperature in terms of manufacturing cost. The polymerization time is 1 second to 360 minutes, and the polymerization pressure is normal pressure to 30 kg / cm ² . The inert hydrocarbon solvent used is the same as described above.

Further, the polymerization activity is improved, the shape of the solid catalyst of the produced polymer is maintained, the catalyst can be easily introduced into the polymerization reaction vessel,
For the purpose of preventing the catalyst from adhering to the polymerization reaction vessel, improving the fluidity in the gas phase reaction vessel, etc., butadiene may be preliminarily polymerized according to the above-mentioned various polymerization methods and used as a catalyst in the main polymerization. .

In order to adjust the molecular weight of the conjugated diene polymer segment (A), a chain transfer agent may be added. As the chain transfer agent, those generally used in the polymerization reaction of cis-1,4-polybutadiene rubber are used. In particular, allenes such as 1,2-butadiene, cyclic dienes such as cyclooctadiene, and hydrogen Is preferably used.

The termination of the polymerization reaction for obtaining the conjugated diene polymer segment (A) is usually carried out by adding a polymerization terminator to the polymerization system when a predetermined conversion is reached. Examples of the polymerization terminator include methanol,
Alcohols such as ethanol, propanol, butanol and isobutanol are used, and they may contain an acid such as hydrochloric acid.

The method of recovering the conjugated diene-based polymer segment (A) after the termination of the polymerization reaction is not particularly limited, and for example, a steam stripping method, precipitation with a poor solvent, or the like may be used.

Among the above-mentioned conjugated diene-based polymer segments (A), particularly preferred conjugated diene-based polymer segments include 50% or more, preferably 70% or more of repeating units derived from 1,3-butadiene. More preferably 80% or more, particularly preferably 90% or more of a copolymer segment or a 1,3-butadiene homopolymer segment, and most preferably a 1,3-butadiene homopolymer segment. If the number of repeating units derived from butadiene is too small, preferable properties based on the large number of cis bonds are impaired. If the cis bond is too small, problems such as a decrease in tensile strength occur, and the rubber loses its desirable properties. The cis bond referred to herein is 1,4-
It is a cis bond.

The weight average molecular weight (Mw) of the conjugated diene polymer segment (A) is from 1,000 to 9,500,000
0, preferably 5,000 to 4,500,000, more preferably 10,000 to 3,000,000, and particularly preferably 20,000 to 2,000,000. If the molecular weight is too small, the physical properties as a polymer such as low mechanical strength become insufficient, and conversely, if the molecular weight is too large, molding becomes difficult.

[Regarding Crystalline Segment (B)] The melting point of the crystalline segment (B) is not particularly limited, but is preferably room temperature or higher. Further, the crystalline segment may be a block copolymer or a part of the molecular chain.

The crystalline segment (B) is not particularly limited, but may be polyethylene, polypropylene, 1,2-polybutadiene, 1,2-syndiotactic polybutadiene, high cis polyisoprene, syndiotactic polystyrene, isotactic polystyrene, or the like. Saturated hydrocarbons, polyvinyl isobutyl ether, polyoxymethylene, polyethylene oxide, ethylene oxide-allyl glycidyl ether copolymer, ethylene oxide
Polyethers such as epichlorohydrin copolymer, ethylene oxide-propylene oxide copolymer, ethylene oxide-propylene oxide-epichlorohydrin copolymer, ethylene oxide-propylene oxide-allyl glycidyl ether copolymer, syndiotactic poly Polyamides such as methyl methacrylate, isotactic polymethyl methacrylate, polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, polyethylene terephthalate, polyvinylidene chloride, nylon, triacetyl cellulose, tributyl cellulose, polyacrylonitrile, etc. Can be mentioned. Preferably, it has partial crystallinity having a melting point higher than room temperature, such as saturated hydrocarbons such as polyethylene, polyethers, syndiotactic polymethyl methacrylate, isotactic polymethyl methacrylate, and polyethylene terephthalate (co). Polymers are preferred, and polyethylene, polypropylene, syndiotactic polystyrene and polyethers are particularly preferred.

[Reinforcing Agent] The reinforcing agent that can be blended in the rubber composition of the present invention is not particularly limited. For example, silica, carbon black, calcium carbonate, magnesium carbonate, titanium oxide, or a surface-treated one thereof is used. And the like.

The silica is not particularly limited, and examples thereof include dry-process white carbon, wet-process white carbon, colloidal silica, and precipitated silica disclosed in JP-A-62-62838. Among these, wet-process white carbon containing hydrated silicic acid as a main component is particularly preferable. These silicas can be used alone or in combination of two or more.

Although the specific surface area of silica is not particularly limited, it is usually 50 to 40 in terms of nitrogen adsorption specific surface area (BET method).
0 m ² / g, preferably at 100 to 250 m ² / g, more preferably in the range of 120~190m ² / g,
Improvements in reinforcement, abrasion resistance, heat generation, workability, and the like are sufficiently achieved, which is preferable. Here, the nitrogen adsorption specific surface area is A
It is a value measured by the BET method according to STM D3037-81.

The carbon black is not particularly limited. For example, furnace black, acetylene black, thermal black, channel black, graphite and the like can be used. Among these, furnace black is particularly preferable, and specific examples thereof include:
SAF, ISAF, ISAF-HS, ISAF-LS,
IISAF-HS, HAF, HAF-HS, HAF-L
Examples include various grades such as S and FEF. These carbon blacks can be used alone or in combination of two or more.

The nitrogen adsorption specific surface area of carbon black (N
₂ SA) is not particularly limited, but is usually 5 to 200 m ² /
g, preferably in the range of 50 to 150 m ² / g, more preferably in the range of 80 to 130 m ² / g, since the tensile strength and abrasion resistance are improved at a high level, which is suitable. The DBP adsorption amount of carbon black is not particularly limited, but is usually 5 to 300 ml / 100 g, preferably 50 to 200 ml.
ml / 100 g, more preferably 80-160 ml / 1
When it is in the range of 00 g, the tensile strength and abrasion resistance are improved at a high level, which is preferable.

As carbon black, JP-A-5-23
No. 0290, the adsorption (CTAB) specific surface area of cetyltrimethylammonium bromide is 110 to 110.
Abrasion resistance can be further improved by using high-structure carbon black having a DBP (24M4DBP) oil absorption of 110 to 130 ml / 100 g after repeatedly applying compression at 170 m ² / g at a pressure of 24,000 psi four times. .

As the surface-modified carbon, JP-A-10-7
If a composite carbon black containing a silica component is used as in JP-A-929-129, the modifying effect is further improved.

The mixing ratio of the reinforcing agent is not particularly limited, but is usually 10 parts by weight or more based on 100 parts by weight of the rubber component.
It is preferably at least 20 parts by weight, more preferably at least 30 parts by weight, and usually at most 200 parts by weight, preferably at most 1 part by weight.
The amount is 50 parts by weight or less, more preferably 120 parts by weight or less.

In order to achieve the object of the present invention to a high degree,
As the reinforcing agent, it is preferable to use silica alone or in combination with silica and other reinforcing agents such as carbon black, calcium carbonate, magnesium carbonate, and titanium oxide. When silica and another reinforcing agent such as carbon black are used in combination, the mixing ratio is appropriately selected according to the application and purpose, but usually, silica: another reinforcing agent such as carbon black = 10: 90 to 99. : 1, preferably 30:70 to 95: 5, more preferably 50:50 to 9
0:10 (weight ratio).

In the present invention, the addition of a silane coupling agent further improves heat buildup and abrasion resistance.
It is suitable.

The silane coupling agent is not particularly restricted but includes, for example, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl)
Ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl)- γ-aminopropylmethyldimethoxysilane, N
-Phenyl-γ-aminopropyltrimethoxysilane,
γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, bis [3- (triethoxysilyl)
Propyl] tetrasulfide and JP-A-6-2481
There can be mentioned tetrasulfides such as γ-trimethoxysilylpropyldimethylthiocarbamyltetrasulfide and γ-trimethoxysilylpropylbenzothiazyltetrasulfide described in JP-A-16.

These silane coupling agents can be used alone or in combination of two or more. The mixing ratio of the silane coupling agent is usually 0.1 to 30 parts by weight with respect to 100 parts by weight of silica,
Preferably 1 to 20 parts by weight, more preferably 2 to 10 parts by weight
It is in the range of parts by weight.

[(I) Other rubber components that can be blended with the block copolymer rubber]
Other rubbers other than the above (i) can be used alone or in combination of two or more with the above block copolymer rubber (i). .

The other rubber is not particularly limited, but a diene rubber used in a general rubber industry can be used. Specifically, for example, natural rubber (N
R), polyisoprene rubber (IR), emulsion-polymerized styrene-butadiene copolymer rubber (SBR), solution-polymerized random SBR (bonded styrene 5 to 50% by weight, 1,2-vinyl bond amount of butadiene bond unit portion 10 to 80) %), High trans SBR (70-95% of 1,4-trans bond in butadiene bond unit portion), low cis polybutadiene rubber (BR), high cis BR, high trans BR (1,4-trans bond in butadiene bond unit portion). Trans-binding amount 70-95%),
Styrene-isoprene copolymer rubber (SIR), butadiene-isoprene copolymer rubber, solution-polymerized random styrene-butadiene-isoprene copolymer rubber (SIBR),
Block copolymers such as emulsion polymerization SIBR, emulsion polymerization styrene-acrylonitrile-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, high vinyl SBR-low vinyl SBR block copolymer rubber, polystyrene-polybutadiene-polystyrene block copolymer, etc. And can be appropriately selected according to the required characteristics. More preferably, it is a diene (co) polymer composed of 0 to 50% by weight of an aromatic monovinyl monomer and 100 to 50% by weight of a conjugated diene monomer. The amount of aromatic monovinyl monomer is preferably from 0.1 to 45% by weight, particularly preferably from 0.5 to 40% by weight. In addition, these polymers have a terminal and / or a part of the main chain at -C (-M) -N =
A bond (where M is oxygen or sulfur), -CN =
(Bond), -OH group and / or quaternary amino group. The combined use of these modified polymers can further improve the exothermic properties of the composition.

When a diene rubber is used as the other rubber, the weight average molecular weight (Mw) in terms of polystyrene of gel permeation chromatography is 100,00.
0 to 2,000,000, preferably 150,000 to
1,500,000, more preferably 200,000-
It is in the range of 1,200,000. Weight average molecular weight (M
If w) is too small, heat build-up and wear resistance will be poor, and if w) is too large, workability will be poor.

There is no particular limitation on the method for producing a diene rubber which is preferable as the other rubber. For example, an organic active metal is used as an initiator in a hydrocarbon solvent.
It can be obtained by (co) polymerizing a conjugated diene or a conjugated diene and an aromatic vinyl. As a method for introducing an -OH group at the terminal of a molecular chain, see JP-A No. 1-18
No. 8,501, or by reacting an active terminal of living polymerization with an alkylene oxide such as ethylene oxide or propylene oxide. In addition, -C (-M) -N = bond or -C-
When a denaturing agent having an N = bond is introduced, see JP-A 64-64.
22940, JP-A-1-101344, JP-A-59-191705, and JP-A-60-1379
No. 13, JP-A-62-86074 and JP-A-6-86074.
There are methods such as Japanese Patent Application Laid-Open No. 2-109801 and Japanese Patent Application Laid-Open No. 62-149708. Japanese Patent Application Laid-Open No. 9-227628 can be cited as a method for quaternization, and the method described in Japanese Patent Application Laid-Open No. 9-183820 can be mentioned as a method for simultaneously introducing an -OH group and a -CN bond. Can be.

The rubber composition of the present invention comprises, in addition to the above components,
According to a conventional method, necessary amounts of other compounding agents such as a vulcanizing agent, a vulcanization accelerator, a vulcanizing activator, an antioxidant, an activator, a plasticizer, a lubricant, and a filler can be respectively contained.

The vulcanizing agent is not particularly restricted but includes, for example, powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur,
Sulfur such as highly dispersible sulfur; sulfur halides such as sulfur monochloride and sulfur dichloride; organic peroxides such as dicumyl peroxide and ditert-butyl peroxide; p-quinone dioxime, p, p'-di Quinone dioximes such as benzoylquinone dioxime; organic polyamine compounds such as triethylenetetramine, hexamethylenediamine carbamate and 4,4'-methylenebis-o-chloroaniline; alkylphenol resins having a methylol group; Of these, sulfur is preferred, and powdered sulfur is particularly preferred. These vulcanizing agents are used alone or in combination of two or more.

The compounding ratio of the vulcanizing agent is usually 0.1 to 15 parts by weight, preferably 0.3 to 10 parts by weight, more preferably 0.5 to 5 parts by weight based on 100 parts by weight of the rubber component. Range. When the compounding ratio of the vulcanizing agent is in this range, it is particularly preferable because it is excellent in tensile strength and wear resistance and also excellent in properties such as heat resistance and residual strain.

Examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazolesulfenamide and N-cyclohexyl-2-benzothiazolesulfenamide.
-T-butyl-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N, N'-diisopropyl-2-
Sulfenamide-based vulcanization accelerators such as benzothiazolesulfenamide; guanidine-based vulcanization accelerators such as diphenylguanidine, diortitolylguanidine, ortho-tolylbiguanidine; thiocarbanilide, diortitolylthiourea, ethylenethiourea, diethyl Thiourea-based vulcanization accelerators such as thiourea and trimethylthiourea; 2-mercaptobenzothiazole, dibenzothiazyl disulfide, 2-mercaptobenzothiazole zinc salt, 2-mercaptobenzothiazole sodium salt,
Thiazole vulcanization accelerators such as mercaptobenzothiazole cyclohexylamine salt and 2- (2,4-dinitrophenylthio) benzothiazole; tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, Thiuram-based vulcanization accelerators such as dipentamethylenethiuram tetrasulfide; sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, sodium di-n-butyldithiocarbamate, lead dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, -Zinc n-butyldithiocarbamate, zinc pentamethylenedithiocarbamate, zinc ethylphenyldithiocarbamate, Acceleration of dithiocarbamic acid vulcanization such as tellurium tildithiocarbamate, selenium dimethyldithiocarbamate, selenium diethyldithiocarbamate, copper dimethyldithiocarbamate, iron dimethyldithiocarbamate, diethylamine diethyldithiocarbamate, piperidine pentamethylenedithiocarbamate, and pipecoline methylpentamethylenedithiocarbamate. Vulcanization accelerators such as sodium isopropyl xanthogenate, zinc isopropyl xanthate and zinc butyl xanthate; and the like.

These vulcanization accelerators can be used alone,
Alternatively, two or more kinds are used in combination, and those containing at least a sulfenamide-based vulcanization accelerator are particularly preferable. The compounding ratio of the vulcanization accelerator is usually 0.1 to 15 parts by weight, preferably 0.1 part by weight, per 100 parts by weight of the rubber component.
It is in the range of 3 to 10 parts by weight, more preferably 0.5 to 5 parts by weight.

The vulcanization activator is not particularly limited, but higher fatty acids such as stearic acid and zinc oxide can be used. As zinc oxide, for example,
It is preferable to use one having a high surface activity and a particle size of 5 μm or less.
Active zinc white of 5 to 0.2 μm and zinc white of 0.3 to 1 μm can be exemplified. As the zinc oxide, a zinc oxide surface-treated with an amine-based dispersant or wetting agent can be used.

These vulcanization activators can be used alone or in combination of two or more.
The mixing ratio of the vulcanization activator is appropriately selected depending on the type of the vulcanization activator. When higher fatty acids are used, rubber component 1
Usually, 0.05 to 15 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight with respect to 00 parts by weight.
Parts by weight. When zinc oxide is used, the rubber component 10
The amount is usually 0.05 to 10 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 0.5 to 2 parts by weight with respect to 0 parts by weight. When the mixing ratio of zinc oxide is within this range,
Properties such as workability, tensile strength and abrasion resistance are highly balanced and suitable.

Examples of other compounding agents include coupling agents other than silane coupling agents; activators such as diethylene glycol, polyethylene glycol and silicone oil; fillers such as calcium carbonate, talc and clay; process oils; Wax and the like.

The rubber composition of the present invention can be obtained by kneading each component according to a conventional method. For example, a rubber composition can be obtained by mixing a compounding agent excluding a vulcanizing agent and a vulcanization accelerator and a rubber component, and then mixing the mixture with a vulcanizing agent and a vulcanization accelerator. The mixing temperature of the compounding agent excluding the vulcanizing agent and the vulcanization accelerator and the rubber component is usually 80 to 200 ° C, preferably 100 to 190 ° C, and more preferably 140 to 18 ° C.
0 ° C., and the mixing time is usually 30 seconds or longer, preferably 1 to 30 minutes. Mixing of the vulcanizing agent and the vulcanization accelerator is usually performed after cooling to 100 ° C. or less, preferably from room temperature to 80 ° C., and then usually press-vulcanized at a temperature of 120 to 200 ° C., preferably 140 to 180 ° C. The rubber composition of the present invention can be obtained.

[0065]

EXAMPLES The present invention will be described below with reference to Production Examples, Comparative Examples and Examples, but the present invention is not limited thereto.

Table 1 shows the reinforcing agents used in the examples. Table 2 shows the formulation. Table 3 shows the polymers, and Table 5 shows the physical property values. In the tables below, all the blending parts are parts by weight.

[0067]

[Table 1] Carbon 1 (Seaast 116 HM manufactured by Tokai Carbon Co., Ltd.) Carbon 2 (Seam KH) Carbon 3 (Seam 6) Carbon 4 (Seam 9) VN-3 is a wet silica Nipsil VN-3 manufactured by Nippon Silica. 1165MP is a wet silica manufactured by Rhone Poulin.

[0068]

[Table 2] * Si69 is a product name of Degussa. * (8%) in the section of the silane coupling agent indicates the weight% of the silane coupling agent used based on the silica weight when silica was used as the reinforcing agent. * Fukor M is a product name of Fujikosan and Suncellar NS is a product name of Sanshin Chemical. * Sulfur # 325 is sulfur powder with a particle size that passes through mesh # 325.

[0069]

[Table 3] * 1: Cannot be measured because it cannot be dissolved. * 2: BR1220 is an abbreviation of “Nipol BR1220” and is a trade name of Zeon Corporation, with a cis content of 96.3%, Mw = 430,000, and Mw / Mn = 2.8. * 3: 1,2BD is “1,2-syndiotactic polybutadiene”.

Production Example 1 A toluene solution of 26.0 g of toluene and 6.7 mmol of methylaluminosane (manufactured by Tosoh Akzo) was placed in a sealed pressure-resistant glass ampoule having an inner volume of 150 ml under a nitrogen atmosphere.
Was charged. While keeping the ampoule at the aging temperature shown in Table 4, 2-methoxycarbonylmethylcyclopentadienyltrichlorotitanium [MeO (CO) CH ₂ CpTi
A solution of 0.003 mmol of [Cl ₃ ] (TiES) in toluene was added dropwise and the aging time shown in Table 4 was maintained. Thereafter, the temperature was lowered to −25 ° C., and 2.0 g of butadiene and 6.
0 g of the solution was added and polymerized at this temperature for 30 minutes.
Subsequently, a pressure of 5 kgf / cm ² was applied to this container with ethylene, and the reaction was carried out for about 1 hour. Thereafter, the polymerization reaction was stopped with a small amount of acidic methanol solution, and then the polymerization solution was poured into a large amount of acidic methanol, and the precipitated white solid was collected by filtration and dried to obtain a butadiene polymer.

Production Example 2 2-methoxycarbonylmethylcyclopentadienyltrichlorotitanium [MeO (CO) 2
Using CH ₂ CpTiCl ₃ ] (TiES), polymerization was carried out in the same manner as in Example 1 under the conditions shown in Table 4. After the completion of the polymerization, ethylene was quickly charged at a pressure of 3 kgf / cm ² , and after 30 minutes, the polymerization was terminated with methanol containing hydrochloric acid. Thereafter, the polymer was dried in the same manner as in Example 1 and used for evaluation of physical properties.

[0072]

[Table 4] BD / Ti is 500 moles of butadiene per mole of titanium
g indicates that the polymerization was carried out. -The polymerization time is 0.05 hours, ie 3 minutes.

Production Example 3 In a 15 (L) autoclave equipped with a jacket and a stirrer, 1,3-butadiene 510 (g) dehydrated with molecular sieve 4A was added to 5100 cc of benzene and water 4.2.
The temperature was adjusted to 30 ° C. by adding mmol. Add DEAC to this solution
28 mmol of (diethylaluminum chloride)
After adding 29.4 mmol of COD (cyclooctadiene) and 0.12 mmol of cobalt octenoate, about 30
For a minute. The resulting polymer was a high cis butadiene rubber with a 96% cis content. Subsequently, 2.1 mmol of carbon disulfide, 8.4 mmol of acetone, and 0.7 mmol of cobalt octenoate were added, and the mixture was further stirred for 30 minutes. The polymerization was terminated by adding 30 cc of methanol containing an antioxidant (BHT: 2,6-di-t-butyl-4-methylphenol) and hydrochloric acid. After removing the solvent by a steam tripping method, the sample was obtained by vacuum drying.
The boiling n-hexane insoluble content of the sample thus obtained was 9 w
%, 1,2 bond amount was 90%, and melting point was 199 ° C. This polymer is composed of high cis butadiene rubber and 9 wt%
Is a mixture of partially crystalline 1,2-syndiotactic polybutadiene.

Examples 1 and 2 and Comparative Examples 1 and 2 Examples 1 and 2 and Comparative Examples 1 and 2
Table 5 shows the physical properties of the crosslinked rubber containing reinforcing agent, which was prepared by blending 0 parts by weight and 50 parts by weight of reinforcing agent Carbon 1 and vulcanizing at 150 ° C. for 15 minutes. All the physical property values are expressed in exponents, and numerical values with Comparative Example 2 being 100, and the higher the value, the better.

The method of measuring the physical property data in the following table is as follows. The rebound resilience is JIS K630
According to No. 1, it was measured using a Lupke rebound resilience tester. For the 300% tensile stress, a 300% stress (kgf / cm ² ) was measured according to JIS K6301. The number of flex fatigue resistance is 2 mm according to JIS K6301.
The number of times until the cracks became 15 mm was measured. Abrasion resistance was measured using a pico abrasion tester according to ASTM D2228. Table 5 shows the relative index with Comparative Example 2 being 100, and Tables 6 and 7 show Comparative Example 3 with 1
The relative index was set to 00.

[0076]

[Table 5] (1) Refers to the polymer obtained in Production Example 1. (2) Refers to the polymer obtained in Production Example 2. (3) Refers to the polymer obtained in Production Example 3. (4) BR1220 is Nipol BR1220, which was explained in the note of Table 3.

Examination of the data in Table 5 reveals that the crystalline rubber mixture of Comparative Example 1 has improved 300% tensile stress and flex fatigue resistance as compared with Comparative Example 2 having no crystallinity.
It can be seen that the abrasion and heat generation characteristics are not sufficient as compared with Examples 1 and 2 of the present invention. The rubber compositions of Examples 1 and 2, which are the rubber compositions of the present invention, are highly balanced, and it can be seen that the balance is further improved when the copolymer block segment is large.

Examples 3 to 7 and Comparative Example 3 In these Examples and Comparative Examples, the type of reinforcing agent was examined. Tables 6 and 7 show the results.

[0079]

[Table 6]

[0080]

[Table 7] * In Production Example 1 and others, 60 parts by weight of the polymer of Production Example 1 were mixed with 40 parts by weight of a commercially available rubber Nipol IR 2200 [high cis isoprene rubber manufactured by Zeon Corporation, cis content of 98% or more]. .

The greater the specific surface area, the more excellent the abrasion,
It can be seen that 300% tensile stress is excellent. In addition, silica, which is a reinforcing agent having a large specific surface area, has wear, rebound,
Although it is shown that the tensile stress of 00% is well-balanced, VN-3, which has an excessively large specific surface area, has rather poor wear characteristics, and thus has an appropriate range.

[0082]

According to the present invention, a rubber composition having excellent low-temperature rebound resilience and tensile stress and having sufficient flex fatigue resistance and a wear index can be provided.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tomohiro Shibuya 2-1-1, Yaiko, Kawasaki-ku, Kawasaki-shi, Kanagawa F-term (reference) 4J002 BP011 BP031 DA036 DE146 DE236 DJ016 FB076 FD010 FD016 FD140 FD150 FD200

Claims (1)

[Claims] 1. (i) (A) a conjugated diene-based polymer segment having a high cis content of 40% or more,
A partially crystalline block copolymer rubber comprising 98% by weight and (B) 90 to 2% by weight of a crystalline segment, having a molecular weight distribution of 4 or less and a weight average molecular weight in terms of polystyrene of 20,000 to 10,000. 2 to 90 parts by weight of a block copolymer rubber which is 1,000,000 and (ii) a reinforcing agent,
And a conjugated diene-based rubber composition containing a crystalline segment.