JP2001316560A - Rubber composition - Google Patents

Abstract

(57) [Summary] [Problem] To provide a rubber composition which is superior in wet grip performance and can be used for shoe soles, grips for golf clubs, and the like. It is attained by using a rubber composition characterized by containing the union and (b) at least one kind of rubber component among natural rubber, diene polymer rubber, and olefin polymer rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition containing an isobutylene-based block copolymer having excellent wet grip properties and suitable for shoe soles, golf club grips and the like.

[0002]

2. Description of the Related Art Conventionally, rubber materials having excellent wet grip properties have been demanded for uses such as shoe soles and grips for golf clubs. In the case of soles, usually on dry ground, the pattern (design) provided on the outsole (ie, the part of the sole that directly contacts the ground) is non-slippery, except when exercising violently. Is hardly slippery. But when it rains,
When the ground is wet, its characteristics are different, so slippage often occurs in ordinary shoes. In addition to grips for golf clubs, grips for rackets such as tennis, badminton, squash, etc., have a feeling of familiarity with the hand when gripped and easy grip, and even when wet with sweat or water, Is required.

[0003] Generally, the wet grip property is related to the hysteresis loss (tan δ) of a rubber material, and 10H
In z, the greater the tan δ at −20 to 0 ° C., the higher the wet grip property.

[0004] Such a rubber composition is disclosed in
JP-A-80433 discloses a rubber composition comprising a brominated polyisobutylene / p-methylstyrene copolymer and a rubber component. However, further improvement in wet grip properties is desired. Further, a rubber composition comprising a styrene-isobutylene-based block copolymer and a rubber component is described in WO98 / 14518 or JP-A-6-200098. It only discloses that it can be used as a rubber material, but does not disclose any use in applications that require special properties such as wet grip properties.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber composition which is excellent in wet grip properties and can be used for shoe soles and golf club grips.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, as a result of diligent studies, an isobutylene-based block copolymer and a rubber composition characterized by containing a rubber component are used. The present inventors have found that a rubber composition having excellent wet grip properties can be obtained, and have reached the present invention.
That is, the present invention provides a block copolymer (a) comprising a polymer block containing isobutylene as a monomer and a polymer block containing an aromatic vinyl-based compound as a monomer, a natural rubber, a diene-based polymer rubber, A rubber composition comprising at least one rubber component (b) among olefin polymer rubbers.

The rubber component (b) is preferably a homopolymer of a diene compound or a copolymer of a diene compound and an aromatic vinyl compound.
It is preferable to mix the block copolymer (a) in an amount of 1 to 40 parts by weight with respect to parts by weight.

The block copolymer (a) is a polymer block having an aromatic vinyl compound as a monomer-a polymer block having isobutylene as a monomer-a polymer having an aromatic vinyl compound as a monomer. It is preferably a triblock copolymer having a united block structure, and the number average molecular weight of the block copolymer (a) is preferably 100,000 or less.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber composition of the present invention comprises a block copolymer (a) comprising a polymer block containing isobutylene as a monomer and a polymer block containing an aromatic vinyl compound as a monomer. A rubber composition comprising at least one rubber component (b) among natural rubber, diene-based polymer rubber, and olefin-based polymer rubber.

The block copolymer (a) which can be used in the present invention is a block copolymer comprising a polymer block containing isobutylene as a monomer and a polymer block containing an aromatic vinyl compound as a monomer. There is no particular limitation as long as it has a structure, for example, a block copolymer, a diblock copolymer, a triblock copolymer, a multiblock having a linear, branched, or star-like structure. Any of copolymers and the like can be selected, and a material that meets the requirements of mechanical properties and workability may be selected.

The polymer block containing isobutylene as a monomer of the present invention may contain a monomer component other than isobutylene, and the content of the monomer other than isobutylene is 3%.
It is preferably at most 0% by weight, more preferably at most 10% by weight.

The monomers other than isobutylene in the isobutylene-based polymer block of the present invention are not particularly limited as long as they are cationically polymerizable monomer components.
Examples thereof include monomers such as aromatic vinyls, aliphatic olefins, dienes, vinyl ethers, and β-pinene. These may be used alone or in combination of two or more.

The aromatic vinyl monomers include styrene, o-, m- or p-methylstyrene, α-methylstyrene, β-methylstyrene, 2,6-dimethylstyrene, 2,4-dimethylstyrene, α-methyl-o-methylstyrene, α-methyl-m-methylstyrene, α-methyl-p-methylstyrene, β-methyl-o-methylstyrene, β-methyl-m-methylstyrene, β-methyl-p -Methylstyrene, 2,4,6-trimethylstyrene, α-methyl-2,6-dimethylstyrene, α-methyl-2,4-dimethylstyrene, β-methyl-2,6-
Dimethylstyrene, β-methyl-2,4-dimethylstyrene, o-, m- or p-chlorostyrene, 2,6-dichlorostyrene, 2,4-dichlorostyrene, α-chloro-o-chlorostyrene, α- Chloro-m-chlorostyrene, α-chloro-p-chlorostyrene, β-chloro-
o-chlorostyrene, β-chloro-m-chlorostyrene, β-chloro-p-chlorostyrene, 2,4,6-trichlorostyrene, α-chloro-2,6-dichlorostyrene, α-chloro-2,4 -Dichlorostyrene, β-chloro-2,6-dichlorostyrene, β-chloro-2,4
-Dichlorostyrene, o-, m- or pt-butylstyrene, o-, m- or p-methoxystyrene, o-,
m- or p-chloromethylstyrene, o-, m- or p
-Bromomethylstyrene, a styrene derivative substituted with a silyl group, indene, vinylnaphthalene and the like. These may be used alone or in combination of two or more.

The aliphatic olefin monomers include ethylene, propylene, 1-butene, 2-methyl-1-butene, 3-methyl-1-butene, pentene, hexene, cyclohexene, and 4-methyl-1-pentene. , Vinylcyclohexane, octene, norbornene and the like.
These may be used alone or in combination of two or more.

Examples of the diene monomer include butadiene, isoprene, hexadiene, cyclopentadiene, cyclohexadiene, dicyclopentadiene, divinylbenzene, and ethylidene norbornene. These may be used alone or in combination of two or more.

The vinyl ether monomers include methyl vinyl ether, ethyl vinyl ether, (n-, iso) propyl vinyl ether, (n-, sec-, te
rt-, iso) butyl vinyl ether, methylpropenyl ether, ethylpropenyl ether and the like. These may be used alone or in combination of two or more.

The polymer block of the present invention containing an aromatic vinyl compound as a monomer may or may not contain a monomer other than the aromatic vinyl compound. Is 60% by weight or more, preferably 80% by weight
It is desirable that this is the case. As the aromatic vinyl monomer, it is preferable to use at least one monomer selected from the group consisting of styrene, α-methylstyrene, p-methylstyrene, and indene. It is particularly preferred to use -methylstyrene or mixtures thereof.

The aromatic vinyl compound of the polymer block of the present invention containing an aromatic vinyl compound as a monomer is not particularly limited as long as it is a cationically polymerizable monomer. And the like.

The ratio of the polymer block containing isobutylene as a monomer and the polymer block containing an aromatic vinyl compound as a monomer is not particularly limited. However, in view of the balance between physical properties and processability, isobutylene is simply used. It is preferable that the polymer block as a monomer is 98 to 40% by weight, the polymer block as a monomer containing an aromatic vinyl compound is 2 to 60% by weight, and the polymer block as a monomer is isobutylene. It is particularly preferred that the content is 95 to 60% by weight, and the content of the polymer block containing an aromatic vinyl compound as a monomer is 5 to 40% by weight.

The preferred structure of the isobutylene-based block copolymer of the present invention is preferably a polymer block-isobutylene containing an aromatic vinyl-based compound as a monomer in view of the physical properties and processability of the resulting composition. Triblock copolymer formed from a polymer block containing a monomer as a monomer and a polymer block containing an aromatic vinyl compound as a monomer, and a polymer block as a monomer containing isobutylene as an aromatic vinyl compound At least one selected from the group consisting of star-shaped polymers having a diblock copolymer composed of a polymer block having a monomer as an arm.

The number average molecular weight of the isobutylene-based block copolymer is not particularly limited. However, from the viewpoint of physical properties and workability, it is preferably from 3,000 to 500,000, and more preferably from 5 to 500,000.
It is particularly preferred that it is 000 to 100,000. When the number average molecular weight of the isobutylene-based block copolymer is lower than the above range, the physical properties of the composition are not sufficiently expressed,
On the other hand, if it exceeds the above range, it is disadvantageous in terms of workability.

The method for producing the isobutylene-based block copolymer is not particularly limited, and a known polymerization method can be used. To obtain a block copolymer having a controlled structure, the following general formula (I) It is preferable to polymerize a monomer component containing no isobutylene as a main component such as a monomer containing isobutylene as a main component and an aromatic vinyl monomer in the presence of the compound represented by 1). (CR ¹ R ² X) _n R ³ (1) wherein X is a substituent selected from the group consisting of a halogen atom, an alkoxyl group having 1 to 6 carbon atoms, and an acyloxyl group having 1 to 6 carbon atoms. Represent. R ¹ and R ² are each
Represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms.
R ¹ and R ² may be the same or different. A plurality of R ¹ and R ² may be the same or different. R ³ represents a polyvalent aromatic hydrocarbon group or a polyvalent aliphatic hydrocarbon group which can have n substituents. n represents a natural number of 1 to 6. Examples of the halogen atom include chlorine, fluorine, bromine and iodine. The alkoxyl group having 1 to 6 carbon atoms is not particularly limited, and includes, for example, a methoxy group, an ethoxy group, an n- or isopropoxy group, and the like. The above-mentioned acyloxyl group having 1 to 6 carbon atoms is not particularly limited, and examples thereof include an acetyloxy group and a propionyloxy group. The hydrocarbon group having 1 to 6 carbon atoms is not particularly limited, and examples thereof include a methyl group, an ethyl group, and n-
Or an isopropyl group.

The compound represented by the above general formula (1) serves as an initiator and generates a carbon cation in the presence of a Lewis acid or the like, and is considered to be a starting point of cationic polymerization. Examples of the compound represented by the general formula (1) used in the present invention include the following compounds.

(1-chloro-1-methylethyl) benze
N C₆H_FiveC (CH_Three)_TwoCl 1,4-bis (1-chloro-1-methylethyl) benze
1,4-Cl (CH_Three)_TwoCC₆H_FourC (CH_Three)_TwoCl 1,3-bis (1-chloro-1-methylethyl) benze
1,3-Cl (CH_Three)_TwoCC₆H_FourC (CH_Three)_TwoCl 1,3,5-tris (1-chloro-1-methylethyl)
Benzene 1,3,5- (ClC (CH_Three)_Two)_ThreeC₆H_Three 1,3-bis (1-chloro-1-methylethyl) -5
(Tert-butyl) benzene 1,3- (C (CH
_Three)_TwoCl)_Two-5- (C (CH_Three)_Three) C₆H_Three Of these, 1-chloro-1-methyl is particularly preferred.
Ruethylbenzene [C ₆H_FiveC (CH_Three)_TwoCl], bis
(1-Chloro-1-methylethyl) benzene [C ₆H
_Four(C (CH_Three)_TwoCl)_Two], Tris (1-chloro-1-
Methylethyl) benzene [(ClC (CH_Three)_Two)_ThreeC₆H
_Three]. [Note that 1-chloro-1-methylethylben
Zen is α-chloroisopropylbenzene, 2-chloro
-2-Propylbenzene or cumyl chloride
Called bis (1-chloro-1-methylethyl) benze
Is bis (α-chloroisopropyl) benzene, bis
(2-chloro-2-propyl) benzene or dicum
Tris (1-chloro-1-me)
Tylethyl) benzene is tris (α-chloroisopro
Pill) benzene, tris (2-chloro-2-propyl)
Also known as benzene or tricumyl chloride
].

In the above polymerization reaction, a Lewis acid catalyst can coexist. Any Lewis acid may be used as long as it can be used for cationic polymerization. TiCl ₄ , TiBr
₄ , BCl ₃ , BF ₃ , BF ₃ .OEt ₂ , SnCl ₄ , SbCl ₅ ,
SbF ₅ , WCl ₆ , TaCl ₅ , VCl ₅ , FeCl ₃ , ZnB
metal halides such as r ₂ , AlCl ₃ , AlBr ₃ ; Et ₂
Organometal halides such as AlCl and EtAlCl ₂ can be suitably used. Above all, considering the ability as a catalyst and industrial availability, TiCl ₄ , B
Cl ₃ and SnCl ₄ are preferred.

The amount of the Lewis acid catalyst to be used is not particularly limited, and can be set in view of the polymerization characteristics or polymerization concentration of the monomer used.

In the above polymerization reaction, an electron donor component can be further co-present if necessary. This electron donor component is considered to have an effect of stabilizing the growing carbon cation during cationic polymerization,
The addition of an electron donor produces a polymer having a controlled structure with a narrow molecular weight distribution. The electron donor component that can be used is not particularly limited, and examples thereof include pyridines, amines, amides, sulfoxides, esters, and metal compounds having an oxygen atom bonded to a metal atom.

The above polymerization reaction can be carried out in an organic solvent as required, and any organic solvent can be used without any particular limitation as long as it does not substantially inhibit cationic polymerization. Specifically, halogenated hydrocarbons such as methyl chloride, dichloromethane, chloroform, ethyl chloride, dichloroethane, n-propyl chloride, n-butyl chloride, and chlorobenzene; benzene, toluene, xylene,
Alkylbenzenes such as ethylbenzene, propylbenzene, and butylbenzene; linear aliphatic hydrocarbons such as ethane, propane, butane, pentane, hexane, heptane, octane, nonane, and decane; 2-methylpropane;
2-methylbutane, 2,3,3-trimethylpentane,
Branched aliphatic hydrocarbons such as 2,2,5-trimethylhexane; cycloaliphatic hydrocarbons such as cyclohexane, methylcyclohexane and ethylcyclohexane; paraffin oil obtained by hydrogenating and purifying a petroleum fraction. it can.

These solvents are used alone or in combination of two or more in consideration of the balance between the polymerization characteristics of the monomers constituting the block copolymer and the solubility of the resulting polymer.

The amount of the above-mentioned solvent to be used is adjusted so that the concentration of the polymer is 1 to 5 in consideration of the viscosity of the obtained polymer solution and the ease of heat removal.
It is determined to be 50 wt%, preferably 3 to 35 wt%.

In conducting the actual polymerization, the components are mixed under cooling, for example, at a temperature of -100 ° C. or more and less than 0 ° C. A particularly preferred temperature range is from -30C to -80C in order to balance the energy cost with the stability of the polymerization.

Examples of the rubber component (b) include natural rubber, diene polymer rubber, and olefin polymer rubber. Examples of the diene polymer rubber include isoprene rubber, butadiene rubber, 1,2-polybutadiene, styrene-butadiene rubber, chloroprene rubber, and nitrile rubber. Examples of the olefin rubber include butyl rubber, chlorinated butyl rubber, brominated butyl rubber, and ethylene-propylene-diene rubber. Among them, a homopolymer of a diene compound or a copolymer of a diene compound and an aromatic vinyl compound is particularly preferable.

The rubber composition of the present invention may further contain, in addition to the above, compounding agents such as fillers, plasticizers, vulcanizing agents, vulcanization accelerators, antioxidants and the like, which are usually used in the rubber industry. It can be appropriately compounded according to the purpose and use. Examples of the filler include carbon black, silica, filler, calcium carbonate, mica, flake graphite and the like. Examples of the plasticizer include petroleum-based process oils such as paraffin-based process oils, naphthene-based process oils, and aromatic-based process oils; dialkyl dibasates such as diethyl phthalate, dioctyl phthalate, and dibutyl adipate; liquid polybutene; Examples thereof include low molecular weight liquid polymers such as isoprene, and among them, liquid polybutene, liquid polyisoprene, and aromatic process oil are preferable in view of compatibility with the rubber component. Examples of the vulcanizing agent include sulfur, a phenol resin, a metal oxide, and a peroxide. These are usually based on 100 parts by weight of the rubber component.
About 0.5 to 10 parts are used. As the vulcanization accelerator,
2,2-dithiobisbenzothiazole, 1,3-diphenylguanidine, tetramethylthiuram disulfide,
Examples include zinc dimethylthiocarbamate and mercaptobenzothiazyl disulfide. These are usually used in an amount of about 0.2 to 5 parts per 100 parts by weight of the rubber component.

It is considered that the wet grip property depends on deformation near the surface of the rubber composition. It is known that the deformation near the surface is a vibration of a very high frequency, and using the temperature-frequency conversion, the wet grip property is -20 ° C. to 0 ° C. tan at 10 Hz.
It is represented by δ. Therefore, tan δ at −20 ° C. to 0 ° C.
The wet grip can be improved by increasing.

The isobutylene-based block copolymer (a) used in the present invention has a large tan δ peak at −20 ° C. to 0 ° C. at 10 Hz due to the presence of a block consisting of an isobutylene skeleton. effective.

The amount of the isobutylene-based block copolymer (a) used in the present invention is not particularly limited and can be appropriately selected depending on the intended purpose. It is preferable to add 1 to 40 parts by weight to 100 parts by weight. If the amount is less than 1 part by weight, it is difficult to obtain an effect of improving wet grip properties, and
Exceeding 0 parts by weight is not preferable because abrasion deteriorates and the balance as a shoe sole tends to be impaired.

The method for preparing the rubber composition of the present invention may be a method conventionally used in the rubber industry. For example, first, an isobutylene-based block copolymer (a), a rubber component (b), Agent, various compounding agents other than the vulcanization accelerator,
After mixing with a tumbler, Henschel mixer, ribo blender or the like, the mixture is kneaded with an extruder, bumper, roll or the like. At this time, it is desirable that the kneading temperature is appropriately changed from room temperature to 200 ° C. depending on the mixing ratio of the isobutylene-based block copolymer (a) and the rubber component (b). This is because the glass transition temperature of the polymer block containing an aromatic vinyl compound of the isobutylene block copolymer as a monomer is usually 100 ° C. or higher, so that the isobutylene block copolymer (a) in the blend is used. This is because when the ratio is high, the components are not sufficiently mixed. Therefore, it is preferable to knead at a higher temperature as the blending amount of (a) is higher. When vulcanized rubber is to be obtained, after kneading, a vulcanizing agent and a vulcanization accelerator are added, and the mixture is further kneaded using the above apparatus. At this time, the kneading temperature is desirably 80 to 120 ° C. for the purpose of suppressing the reaction of the vulcanizing agent. further,
If necessary, the rubber composition can be molded and cross-linked using a press or an injection molding machine.

Although there are no particular restrictions on the embodiment of the present invention, preferred embodiments include grips for tennis shoes, badminton, squash, etc., shoe tires, golf club grips, and automobile tires.

[0039]

The present invention will be described more specifically with reference to the following examples. It should be noted that the present invention is not limited in any way by these embodiments, and can be appropriately changed and implemented without changing the gist thereof. (Production Example 1): Production of styrene-isobutylene-styrene-triblock copolymer. In a 2 L reaction vessel equipped with a stirrer, 570 mL of methylcyclohexane (dried with molecular sieves), n-
590 mL of butyl chloride (dried with molecular sieves) and 0.400 g of dicumyl chloride were added. After cooling the reaction vessel to −70 ° C., 0.34 mL of α-picoline (2-methylpyridine) and isobutylene 1
74 mL was added. 10.3 mL of titanium tetrachloride
Was added to initiate polymerization, and the mixture was reacted at −70 ° C. for 2.0 hours while stirring the solution. Then, styrene 58 was added to the reaction solution.
After adding mL and continuing the reaction for another 60 minutes, a large amount of methanol was added to stop the reaction. After removing the solvent and the like from the reaction solution, the polymer was dissolved in toluene and
Washed twice. This toluene solution was added to the methanol mixture to precipitate a polymer, and the obtained polymer was treated at 60 ° C. for 24 hours.
An isobutylene-based block copolymer was obtained by vacuum drying for an hour (hereinafter abbreviated as SIBS).

The obtained isobutylene block copolymer had a number average molecular weight of 98,000 and a molecular weight distribution of 1.15.
The styrene content in the polymer was 29% by weight. The number average molecular weight was measured using a Waters 510 type GPC system (chloroform was used as a solvent, and the flow rate was 1 mL / min), and the value in terms of polystyrene was shown. The styrene content in the polymer was calculated from the integral ratio of the ¹ H NMR spectrum.

(Examples 1 to 4) Styrene-butadiene copolymer rubber (JSR0120, manufactured by JSR, hereinafter referred to as SBR)
Abbreviated. ), Butadiene rubber (JSR BR31, JS
R Company, hereinafter abbreviated as BR. ), SI manufactured in Production Example 1
BS and other compounding agents were kneaded at a compounding ratio shown in Tables 1 and 2 with a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.) set at 150 ° C. for 15 minutes to obtain a rubber composition. The rubber composition was compression molded at 150 ° C. to produce a sheet.
The moldability was extremely good. 6 mm long from the sheet
A test piece having a width of 5 mm and a thickness of 2 mm was cut out, and the loss tangent tan δ at 0 ° C. was measured using a dynamic viscoelasticity measuring device DVA-200 (manufactured by IT Measurement Control Co., Ltd.). The measurement frequency was 10 Hz.

Comparative Example 1 As a comparative example, SBR was compression-molded at 150 ° C. without adding any SIBS, and a sheet was produced. Loss tangent t at 0 ° C. in the same manner as in Examples 1 to 3.
anδ was measured.

(Comparative Example 2) As a comparative example, SEBS was added to SBR instead of SIBS, and kneaded with a Labo Plastomill (manufactured by Toyo Seiki) set at 150 ° C for 15 minutes.
The rubber composition was compression molded at 150 ° C. to produce a sheet. In the same manner as in Examples 1 to 3, the loss tangent ta at 0 ° C.
nδ was measured. The wet grip property is given by the following equation (2)
It is represented by Wet grip property (%) = tan δ (0 ° C.) of each composition / tan δ (0 ° C.) of SBR alone × 100 (2)

[0044]

[Table 1]

[0045]

[Table 2]

In Examples 1 to 3, tan δ at 0 ° C. was higher than that of SBR alone (Comparative Example 1) by adding SIBS, that is, the wet grip property was improved.
Also, when SEBS (G1650, manufactured by Shell) was used instead of SIBS (Comparative Example 2), tan δ at 0 ° C. was reduced and wet grip property was reduced as compared with SBR alone (Comparative Example 1). are doing.

[0047]

EFFECT OF THE INVENTION The rubber composition of the present invention is obtained by blending a conventionally used rubber component with an isobutylene-based triblock copolymer to obtain a shoe sole having excellent wet grip properties and a grip for golf clubs. Can be used.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 23/22 C08L 23/22 23/28 23/28 F-term (Reference) 4J002 AC011 AC031 AC041 AC061 AC081 AC091 BB151 BB181 BB241 BP032 FD010 FD020 FD140 FD150 GC00 GN01 4J026 HA02 HA28 HA32 HA39 HB05 HB06 HB08 HB28 HB39 HB48 HE01 HE02 HE05

Claims (5)

[Claims] 1. A block copolymer (a) comprising a polymer block containing isobutylene as a monomer and a polymer block containing an aromatic vinyl compound as a monomer, a natural rubber, a diene polymer rubber, A rubber composition comprising at least one rubber component (b) among olefin polymer rubbers. 2. The rubber composition according to claim 1, wherein the rubber component (b) is a homopolymer of a diene compound or a copolymer of a diene compound and an aromatic vinyl compound. 3. The rubber composition according to claim 1, wherein the block copolymer (a) is compounded in an amount of 1 to 40 parts by weight with respect to 100 parts by weight of the rubber component (b). 4. A block copolymer (a) comprising a polymer block containing an aromatic vinyl compound as a monomer, a polymer block containing isobutylene as a monomer, and an aromatic vinyl compound as a monomer. The rubber composition according to any one of claims 1 to 3, which is a triblock copolymer having a structure of a polymer block. 5. The rubber composition according to claim 1, wherein the number average molecular weight of the block copolymer (a) is 100,000 or less.