JPH0138809B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a rubber composition containing a styrene-butadiene copolymer having a specific structure and a polybutadiene having a specific structure, and the composition of the present invention has good mechanical properties, processability, and dynamic properties. It is an excellent composition suitable for various rubber applications. In addition to conventional natural rubber and styrene-butadiene copolymer rubber obtained by emulsion polymerization, the raw rubber used in various vulcanized rubber products such as automobile tires, anti-vibration rubber, and footwear includes high-quality rubber. Various solution polymerized rubbers brought about by the development of molecular polymerization technology include, for example, polyisoprene rubber obtained using Ziegler-Natta catalysts, high cis-polybutadiene rubber, ethylene-propylene copolymer rubber, etc. Examples include low cis-polybutadiene rubber obtained by polymerization using a system catalyst and styrene-butadiene copolymer rubber, which are used alone or as a blend as raw materials for various vulcanized rubber products. Among the various solution-polymerized rubbers mentioned above, polybutadiene rubber and styrene-butadiene copolymer rubber obtained using a lithium-based catalyst can be used, for example, as catalyst additives such as ether, thioether, tertiary amine, hexamethylphosphorotriamide. By adding polar substances such as, it is possible to obtain polymers with different microstructures of the butadiene moiety, and by changing the method of adding monomers, random copolymers and block copolymers can be obtained. It is a polymer that has been attracting attention in recent years because it is possible to change the polymer structure. Among the polymers obtained using these lithium-based catalysts, Japanese Patent Publication No. 49-4311 discloses that the amount of 1,2-bonds (synonymous with vinyl bonds) in the microstructure is 25 to 50.
%, 1,4-trans bond amount is 15-55%, 1,4
- Rubber compositions for tires using polybutadiene having a cis bond content of 10 to 40% are disclosed. When polybutadiene with such a microstructure is used in tire treads, it exhibits satisfactory abrasion resistance and wet skid resistance (slip resistance on sloppy roads), but on the other hand, it has poor processability when processing or molding rubber. was not necessarily satisfactory. On the other hand, styrene and butadiene can be
The styrene-butadiene copolymer obtained by polymerization using a lithium-based catalyst in the presence of a polar substance such as a class amine has a higher amount of vinyl bonds than that obtained by polymerization without using a polar substance. , for example, has a vinyl bond content of 20 to 30%, and tire rubber compositions using styrene-butadiene copolymers with these vinyl bond content are different from general low cis-polybutadiene and vinyl bond content. Compared to styrene-butadiene copolymers containing 20% or less, there were problems with wear resistance and other issues. Furthermore, in recent years in the rubber industry, vulcanization has been carried out under conditions of higher temperature and shorter time than conventional vulcanization conditions for the purpose of improving productivity. However, when vulcanization is carried out at high temperatures for a short period of time, there is a difference in the vulcanization state between the center and the outside of the molded product due to heat conduction, resulting in over-vulcanization on the outside. A phenomenon called "cure reversion" is likely to occur, resulting in problems such as deterioration of the physical properties of the vulcanized product. For this reason, there has been a demand for a raw material rubber that has less vulcanization reversion and can be vulcanized at high temperatures and for short periods of time. As a result of intensive studies aimed at improving the problems of rubber, the present inventors have developed a rubber composition containing a specific styrene-butadiene copolymer, a specific polybutadiene, and other rubber-like substances. However, it is a rubber composition with excellent processability, a good balance between abrasion resistance and wet skid resistance, little reversion during vulcanization, and other excellent properties, making it suitable for various vulcanized rubber applications including tire applications. The present invention has been arrived at by discovering that it is suitable for The present invention consists of (A) component: a styrene-butadiene copolymer with a styrene content of 10 to 60% by weight and a vinyl bond amount of 25% to less than 60% in the butadiene moiety; (B) component: a vinyl bond amount of Component C: selected from natural rubber, polyisoprene, polybutadiene or styrene-butadiene copolymer with a styrene content of 0 to 60% by weight and a vinyl bond content of the butadiene portion of 1 to 20%. A rubber composition that uses one or more rubber-like conjugated diene polymers as a raw material rubber, and contains component (A) and (B).
The weight ratio of the components is 20-80:80-20, and the (A) component and
The weight ratio of the total amount of component (B) to component (C) is 100~
25:0 to 75, and the rubber composition
This is a rubber composition for vulcanization containing (D) a reinforcing agent and (E) a vulcanizing agent. The styrene-butadiene copolymer used as component (A) of the present invention has a styrene content of 10 to 60% by weight, preferably 10 to 55% by weight, particularly preferably 15 to 50% by weight.
It is a copolymer of If the styrene content is less than 10% by weight, processability will be insufficient and the resulting rubber composition will have poor tensile strength and wet skid resistance. On the other hand, if the above amount exceeds 60% by weight, the resulting composition will have insufficient rebound elasticity and abrasion resistance. The amount of vinyl bonds (1,2-bond amount) in the butadiene part of the styrene-butadiene copolymer (A) component is
The range is 25% or more and less than 60%, preferably 35% or more and less than 60%, particularly preferably 40% or more and less than 60%. When the amount of vinyl bonds is less than 25%, vulcanization reversion tends to occur, and the skid resistance of the obtained composition is insufficient, and when it exceeds 60%, the abrasion resistance of the composition is poor. The styrene-butadiene copolymer (A) is a polymer in which styrene exists uniformly along the molecular chain, a polymer in which the amount of styrene increases or decreases along the molecular chain, and a polymer in which the amount of styrene increases or decreases along the molecular chain. A block copolymer having one or more blocks consisting of a copolymer or polystyrene containing a large amount of styrene and one or more blocks consisting of a copolymer or polybutadiene containing a small amount of styrene may be used. Amount of styrene (J.Polym Sci 1
429 (1946)) is 5% by weight of the copolymer.
The following is preferable from the viewpoint of exothermic properties of the resulting composition. In addition, similar to styrene, copolymers in which the amount of vinyl bonds in the butadiene portion is uniform along the molecular chain, copolymers in which the number of vinyl bonds increases or decreases, and areas with many and few vinyl bonds in a block shape are also available. Any of the copolymers present in
(A) Can be used as component. The number average molecular weight of the styrene-butadiene copolymer of component (A) is preferably 50,000 to 400,000, more preferably 75,000 to 300,000, and the molecular weight distribution (weight average molecular weight [Mw] and number average molecular weight [Mn] The ratio (Mw/Mn) is preferably 1.1 to 4.0, more preferably 1.2 to 3.0. Component (A) is added to 100 parts by weight of the total amount of component (A) and component (B) described below. is 20 to 80 parts by weight, preferably 25
It is used in a composition of ~75 parts by weight, and outside the above composition range, the effect is slight compared to using each alone. The polybutadiene as component (B) of the present invention is rubbery and has a vinyl bond content of 25 to 95%, preferably 25 to 70%. If the amount of vinyl bonds is less than 25%, the wet skid resistance and processability will be poor, and the resulting composition will likely be uncured during the vulcanization process. Moreover, if the above amount exceeds 95%, problems arise in the abrasion resistance, rebound elasticity, etc. of the resulting composition. Furthermore, the number average molecular weight of the polybutadiene as component (B) is preferably 50,000 or 400,000, more preferably 75,000 to 300,000, and the molecular weight distribution is preferably 1.1 to 4.0, still more preferably 1.2 to 3.0. Component (B) is used in an amount of 20 to 80 parts by weight, preferably 25 to 75 parts by weight, based on 100 parts by weight of the total amount of components (A) and (B). In the present invention, component (A) and component (B) are used within the above composition range, but preferably component (A) and (B)
The structure and composition of each of component (A) and component (B) such that the styrene content as a mixed composition with the components is 10 to 40% by weight, and the amount of vinyl bonds in the butadiene portion is 35 to 80%. The use of styrene is advantageous in terms of the balance between processability and wear resistance of the resulting composition, and more preferably, the styrene content is
15 to 35% by weight, and the amount of vinyl bonding is 40 to 70%. The styrene-butadiene copolymer of component (A),
The polybutadiene of component (B) obtained by any production method can be used as the raw rubber component of the present invention as long as it satisfies the above-mentioned limiting conditions. Component (A), the styrene-butadiene copolymer, is typically manufactured using an organic lithium such as n-butyllithium or sec-butyllithium as a polymerization catalyst in an inert solvent such as hexane, cyclohexane, or benzene. If necessary, other organic compounds such as alkoxides such as potassium butoxide and organic acid salts such as dodecylbenzene sulfonate may be used as co-catalyst components. It can be obtained by copolymerizing styrene and butadiene using a polar compound such as amine, polyamine, thioether, hexamethylphosphortriamide, etc. The polymerization process may be a batch polymerization process, a continuous polymerization process, or a combination thereof. Furthermore, a branched or radial copolymer can be obtained by coupling the polymer chain having an active end obtained by the above method with silicon tetrachloride, tin tetrachloride, divinylbenzene, etc. You can also do it. In addition, in the polymerization method, by changing the polymerization conditions such as adjusting the monomer addition method or changing the amount of the vinyl bond regulator during the polymerization, it is possible to
It is also possible to obtain a polymer in which the styrene content and the amount of vinyl bonds increase or decrease continuously, or in a block-like manner. Also, acetylene,
1,2-butadiene, fluorene, primary amine,
Various molecular weight modifiers such as secondary amines are also used. The polybutadiene used as component (B) is produced by homopolymerizing butadiene in almost the same manner as the styrene-butadiene copolymer of component (A), and further by the above-mentioned post-treatment method. Polybutadiene of various structures can be obtained. Next, the rubbery polymer as component (C) used in the rubber composition of the present invention is natural rubber, polyisoprene, has a styrene content of 0 to 60% by weight, and has a vinyl bond content of 1 to 20% in the butadiene moiety. 1 selected from certain polybutadiene or styrene-butadiene copolymers
The rubber-like conjugated diene polymer is one or more kinds of rubber-like conjugated diene polymers, and natural rubber and/or polyisoprene are particularly preferred. The above-mentioned natural rubber, polyisoprene, polybutadiene, or styrene-butadiene copolymer are raw rubbers that are generally used for rubber applications. In the rubber composition of the present invention, the rubber-like substance of component (C), component (A) and component (B) are composed of component (A) and component (B).
Total amount of components 25 to 100 parts by weight, component (C) 75 to 0 parts by weight, preferably total amount of components (A) and (B) 30 to 100 parts by weight.
parts by weight, component (C) is 70 to 0 parts by weight, component (A), (B)
The total amount of component (C) is 100 parts by weight. If the total amount of components (A) and (B) is less than 25 parts by weight, the effect of improving the recovery of vulcanization of component (C) in the vulcanization process of the composition is slight. Next, the characteristics of the rubber composition obtained by the present invention will be described. The characteristics of the rubber composition of the present invention when the two components (A) and (B) are used as raw rubber are: (1) Abrasion resistance compared to when component (A) alone is used as raw rubber; , excellent rebound elasticity. (2) Processability and wet skid resistance are better than when component (B) alone is used as a raw material rubber. (3) Compared to a composition using a styrene-butadiene copolymer having a styrene content and a vinyl bond amount corresponding to component (A) + component (B) of the present application, it has improved wear resistance and wet skid resistance. Excellent balance of resistance and excellent workability. (4) Emulsion polymerized styrene-butadiene copolymer rubber, the amount of vinyl bond obtained by solution polymerization is
Compared to compositions using 15% or less styrene-butadiene rubber or polybutadiene rubber as raw material,
It has greatly improved wet skid resistance and improved vulcanization recovery during the processing process. There is a particular thing. In addition, the characteristics of a rubber composition in which component (C) is added to components (A) and (B) are as follows: (1) natural rubber, polyisoprene, polybutadiene or styrene-butadiene used in component (C); It has the effect of improving vulcanization recovery of the polymer. As shown above, the rubber composition according to the present invention has
This is a useful rubber composition that could not be achieved by using conventional raw material rubbers or a combination of conventional raw material rubbers, and is suitable for automobile tires, anti-vibration tires, footwear, etc. It is particularly suitable for tire tread because of its excellent abrasion resistance and wet skid resistance. The rubber composition of the present invention comprises the above-mentioned (A) component, (B) component, and (C)
The ingredients are raw rubber, and by adding various compounding agents to it and vulcanizing it, it can be used for various purposes including tires. Compounding agents added to the above rubber composition include reinforcing agents, softeners, fillers, vulcanizing agents, vulcanization accelerators, vulcanization aids, scorch inhibitors, anti-aging agents or antioxidants, and adhesives. Additives, colorants, flame retardants,
There are lubricants, foaming agents, and other compounding agents, and these are appropriately selected and used as necessary. Carbon black is a typical reinforcing agent, and various products with different particle sizes or structures made by various manufacturing methods are used, but carbon blacks such as ISAF, HAF, and FEF are mainly used in tires. It is suitable for use in applications such as The amount of carbon black to be added is determined by taking into consideration the amount of process oil used at the same time, but it is 10 to 150 parts by weight, preferably 20 to 100 parts by weight, per 100 parts by weight of raw rubber. Ru. The type and amount of carbon black added are appropriately adjusted depending on the intended use of the rubber composition, and two or more types may be used in combination. Other reinforcing agents used include inorganic reinforcing agents such as silica and activated calcium carbonate, high styrene resins, and phenol-formaldehyde resins. ~100 parts by weight are used, preferably 1 to 50 parts by weight. Typical softeners added as needed include process oils, and paraffinic, naphthenic, and aromatic softeners are preferably used in rubber compositions, and are added in amounts of 2 to 100 parts by weight per 100 parts by weight of raw rubber. 100 parts by weight,
Preferably 5 to 70 parts by weight are used. It is also possible to use oil-extended polymers in which process oil is added to the raw rubber in advance. Other softeners include liquid paraffin, coal tar, fatty oils,
Sub, etc. As a filler, calcium carbonate, clay,
Examples include talc and aluminum. A typical example of the vulcanizing agent is sulfur, which is used in an amount of 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, per 100 parts by weight of raw rubber. Other vulcanizing agents include sulfur compounds such as sulfur chloride, morpholine disulfide, and alkylphenol disulfide, and peroxides, which may be used alone or in combination with sulfur. There are a wide variety of vulcanization accelerators,
These are used in an amount of 0.01 to 5 parts by weight per 100 parts by weight of raw rubber, and two or more types can also be used in combination. Typical vulcanization accelerators include guanidine,
aldehyde-amine and aldehyde-ammonia systems, thiazole systems, imidazoline systems, thiourea systems, thiuram systems, dithiocerbamate systems,
Examples include xanthate type and mixing accelerators. As a vulcanization aid, metal oxides such as zinc oxide,
These include fatty acid compounds such as stearic acid and amines, which are present in amounts ranging from 0.1 to 100 parts by weight of raw rubber.
10 parts by weight are used. Typical anti-aging agents or antioxidants that are added as needed are amine-based, phenol-based, phosphorus-based, etc.
It is added in an amount of 0.001 to 10 parts by weight per 100 parts by weight, and two or more types may be used in combination. Typical scorch inhibitors that may be added as needed include phthalic anhydride, salicylic acid, and N-nitroso diphenylamine, and 0.1 to 2.0 parts by weight are used per 100 parts by weight of raw rubber. be done. Furthermore, tackifiers that are added as necessary include chroman-indene resin, terpene-phenol resin, rosin ester, etc., and are used in an amount of 0.1 to 10 parts by weight per 100 parts by weight of raw rubber. be done. In addition, various other compounding agents may be added as necessary.
It is used by adding it to rubber compositions. The rubber composition of the present invention is produced by mixing raw rubber and various compounding agents using various mixing devices generally used for mixing rubber compositions, such as open rolls, Banbury mixers, kneaders, extruders, etc. It is then molded into the desired shape and vulcanized. The rubber composition of the present invention can be used in tires, belts, etc. for various automobiles such as trucks, buses, passenger cars, and small cars.
Due to its characteristics, it is suitable for use in industrial products such as hoses and anti-vibration rubber, footwear, daily necessities, construction materials, and various other applications. Examples are shown below, but these are intended to explain the present invention more specifically, and are not intended to limit the scope of the present invention. Reference Example Representative examples of the polymerization method of the styrene-butadiene copolymer and polybutadiene used in the present invention are shown below. (1) In the case of sample A-3: Use one polymerization reactor with an internal volume of 10, equipped with a stirrer and a jacket, and set the internal temperature of the polymerization reactor to 98 to 102
℃, and from the bottom of the reactor, monomers such as butadiene at 24 g/min, styrene at 8.5 g/min, hexane at 130 g/min as a solvent, tetrahydrofuran at 2.3 g/min as a polar compound, and n-butyllithium as a catalyst are added as monomers. The polymerization reaction was started by continuously feeding 0.036 g per 100 g using a metering pump, and the polymer solution was continuously drawn out from the top of the reactor. After reaching a steady state, 0.5 parts by weight of di-tert-butyl-P-cresol per 100 parts by weight of the polymer was added to the obtained polymer solution, and then the hexane solvent was removed. The analytical values of the obtained polymer are as shown in Table 1. The styrene content and the microstructure of the butadiene moiety were measured using an infrared spectrophotometer and calculated by Hampton's method. In addition, when sample A-3 was analyzed by G, P, and C, the weight average molecular weight (Mw) was 343,000.
Number average molecular weight (Mn) is 163000, Mw/Mn=
It was 2.10. For G, P, and C, LC-1 type manufactured by Shimadzu Corporation was used, the detector was a differential refractometer, the solvent was tetrahydrofuran, and the column was H.
One tube each of S, G-50, 60, and 70 was measured at a temperature of 40°C. (2) Polymerization of sample A-4 A 40-inner volume polymerization reactor equipped with a stirrer and a jacket was used, and cyclohexane was added to the reactor.
18.2Kg, butadiene 2.9Kg, styrene 1.6Kg, diethylene glycol dimethyl ether 7.0g,
3.0 g of n-butyllithium was added, and the reactor internal temperature was maintained at 45 to 55° C., and polymerization was carried out for 1 hour. After the polymerization was completed, 3.0 g of silicon tetrachloride was added to the polymer solution to cause a coupling reaction. Add 0.5 parts by weight of di-tert per 100 parts by weight of the polymer to this polymer solution.
After adding butyl-P-cresol, the solvent was removed to obtain sample A-4. The analytical values of sample A-4 are shown in Table 1. Also, Mw of sample A-4 =
284000, Mn=164000, Mw/Mn=1.73. Table 1 shows the analytical values of the styrene-butadiene copolymer used in the present invention together with A-3 and A-4. Among these, samples A-1, A-2, A-
5. A-6, A-7, and A-8 were prepared using the same polymerization method as sample A-3 or A-4, but with different amounts of butadiene and styrene supplied, amount of catalyst, amount of polar compound added, polymerization temperature, etc. This is what I got.
In addition, samples a-1 and a-2 are polymers obtained by polymerizing without using a vinylizing agent by the continuous polymerization method used to obtain sample A-3, and sample a-3 is a polymer obtained by polymerizing using a commercially available emulsion polymerization method. It is a styrene-butadiene copolymer (SBR-1502). In addition, Table 2 shows the analytical values of polybutadiene used in the present invention, and samples B-1 to B-6
is a polymer obtained by polymerizing only butadiene as a monomer by the polymerization method using the vinylating agent used to obtain sample A-3 or A-4, and sample b
-1 is a commercially available low-cis polybutadiene (diene-
50R), sample b-2 is a commercially available high cis-polybutadiene (Nipole-1220). Note that the microstructure of polybutadiene was calculated by the Morello method by measuring the spectrum using an infrared spectrophotometer.

【table】

【table】

[Table] Example 1 Various styrene-butadiene copolymers shown in Table 1 and various polybutadienes shown in Table 2 were used, and these polymers or their compositions shown in Table 3 were used as rubber components, and Table 4 The mixture was mixed using a Banbury mixer according to the formulation method described in . Mixability in the Banbury mixer was good in all cases. Further, these compositions were formed into a sheet of a predetermined thickness using a heated roll (8 inches), a ribbon of a predetermined width was prepared, and extrusion processability was evaluated using a Garvey die extruder. The evaluation results of workability are shown in Table 3.
It was shown to. Further, these compounds were press-vulcanized at 140°C, and their physical properties were measured, and the results shown in Table 3 were obtained. The results shown in Table 3 will be explained below. In Examples 1-1 to 1-4, sample A-7 was replaced with sample B.
Comparative Example 1-1 with Sample A-7 as the rubber component and Sample B-4 as the rubber component. Compared to the composition of Comparative Example 1-2, the relationship between wear resistance and wet skid resistance is improved. Moreover, Comparative Examples 1-5 are controls for this evaluation. The blended rubber component of Example 1-3 is A-4 of the rubber component used in Comparative Example 1-5.
It has almost the same styrene content and microstructure. The composition of Examples 1-3 is the same as that of Comparative Example 1.
Compared to -5, it maintains wet skid resistance, has improved wear resistance, and has excellent workability. Furthermore, the compositions of Examples 1-1 to 1-4 are Comparative Example 1-6 and Comparative Example 1-6 using styrene-butadiene copolymers a-1 and a-2 having a low vinyl content polymerized with a lithium catalyst. The compositions of Examples 1-7 and
Compared to the compositions of Comparative Examples 1-8 using commercially available emulsion-polymerized styrene-butadiene copolymers, the wet skid resistance is greatly improved, and the processability is also the same or better. As described below, the composition of the present invention can be said to have excellent processability and mechanical properties.

【table】

[Table] *2 Measured at room temperature using a Danlopt tripometer.
*3 Measured using a pico abrasion tester, Comparative example 1〓1(
Displayed as an index with control) as 100.
*4 Measured on a concrete road surface using a device manufactured by the British Road Research Institute and expressed as an index with Comparative Example 1 = 1 as 100 *5 Measured by ASTM = D = 638 = 58 (A) Table 4 Rubber 100 Parts by weight Aromatic process oil 5 parts by weight ISAF grade carbon black 45 parts by weight Stearic acid 2 parts by weight Zinc oxide 4 parts by weight Antioxidant B ^*1 1 part by weight Vulcanization accelerator CZ ^*2 1 part by weight Sulfur 1.7 parts by weight* 1 Reactant of diphenylamine and acetone *2 N-cyclohexylbenzothiazole sulfenamide Example 2 Rubber using the compounding method shown in Table 4 and using the polymer or blend of polymers shown in Table 5 as the rubber component A composition was obtained in the same manner as in Example 1. Table 5 shows the measurement results of these vulcanizate physical properties. In addition, in Table 5, a rubber composition using Sample A-2, which was used as a comparative example in Example 1, was used as a control. Further, Table 5 also shows some of the results of Example 1 for reference. The compositions of Examples 2-1 to 2-2 using rubber components within the scope of the present invention had improved abrasion resistance compared to the composition of Comparative Example 1-5 using the control A-2. has been done. On the other hand, the compositions of Comparative Examples 2-1 to 2-5 and Comparative Example 1-2 using only the rubber component used in these Examples were the same as the control Comparative Example 1-5.
The compositions of Comparative Examples 2-4, 2-5, and 1-2 using polybutadiene as a rubber component have the same or lower tensile strength in terms of wet skid resistance and abrasion resistance. is inferior. Furthermore, Comparative Example 2-6 using a styrene-butadiene copolymer outside the scope of the present invention as component (A),
The compositions of Comparative Examples 2-10, in which polybutadiene outside the range of the present invention was used as component (B), were inferior in wet skid resistance and poor heat build-up compared to the compositions of the present invention.

[Table] Example 3 A rubber composition containing the copolymers listed in Table 7 or a blend thereof as a rubber component was obtained in the same manner as in Example 1 using the compounding method shown in Table 6.
Table 7 shows the measured values of physical properties. Example 3 using rubber components within the scope of the present invention-
The rubber compositions Nos. 1 to 3-5 are superior to the rubber composition using control sample A-5 (Comparative Example 3-1) in terms of abrasion resistance and wet skid resistance. The rubber compositions using polybutadiene of Comparative Examples 3-2 and 3-3 have poor tensile strength. Table 6 Rubber 100 parts by weight Maromatic process oil 37.5 parts by weight HAF grade carbon 68.8 parts by weight Stearic acid 1 part by weight Zinc white 3 parts by weight Vulcanization accelerator NS ^*1 1.38 parts by weight Sulfur 1.5 parts by weight *1 N-tert- Betylbenzothiazole sulfenamide Example 4 A rubber composition was obtained in the same manner as in Example 1 using the copolymer shown in Table 8 and the blending method shown in Table 6. Examples 4-1 and 4-2 are compositions in which the rubber component is a blend of components (A) and (B) of the present invention, and the styrene content and microstructure are almost the same. Compared to the composition of Comparative Example 4-1 using Sample A-1, it is superior in abrasion resistance and wet skid resistance.

【table】

【table】

【table】

[Table] Example 5 As component (C), C-1 (natural rubber), C-2 (polyisoprene rubber) and a- shown in Table 9 were used.
2 (styrene-butadiene rubber) b-1 (low cis polybutadiene rubber) and b-2 (high cis polybutadiene rubber) were used to prepare 3 components (A), (B), and (C) shown in Table 10. A rubber composition was obtained in the same manner as in Example 1 using the rubber component as the component and using the compounding method shown in Table 4. When the rubber components shown in the examples in Table 10 were used, all had good blendability with component C. Table 10 shows the physical property values of the vulcanized products and the results of measuring the recovery from vulcanization of these rubber compositions. As shown in Table 10, the composition using a styrene-butadiene copolymer with a small amount of vinyl in Comparative Examples 5-6 has little effect on preventing the re-vulcanization of natural rubber or polyisoprene rubber. 5
The compositions -1, 5-2, and 5-3 of the present invention all have little reversion of vulcanization and are sufficiently effective in preventing reversion of the rubber component used in component (C).

【table】

【table】

【table】

[Table] *1 Measurement of recovery from vulcanization Measure the change in torque of a composition containing a vulcanizing agent at 160°C using a cuelastrometer (torque after 60 minutes/maximum torque) x 100 (%). The smaller the number, the more intense the recovery from vulcanization.

Claims (1)

[Scope of Claims] 1 Component (A): A styrene-butadiene copolymer having a styrene content of 10 to 60% by weight and a vinyl bond content in the butadiene moiety of 25% to less than 60%, Component (B): Vinyl Polybutadiene (C) component with a bonding amount of 25 to 95%: natural rubber, polyisoprene, polybutadiene or styrene-butadiene copolymer with a styrene content of 0 to 60% by weight and a vinyl bonding amount of the butadiene portion of 1 to 20%. A rubber composition that uses as a raw material rubber one or more rubber-like conjugated diene-based polymers selected from the combination of components (A) and (B).
The weight ratio of the components is 20-80:80-20, and the (A) component and
The weight ratio of the total amount of component (B) and component (C) is 100 to 25:
0 to 75. 2. Claim 1, in which the styrene content of the polymer composition obtained by mixing component (A) and component (B) is 10 to 50% by weight, and the amount of vinyl bonds in the butadiene portion is 35% or more and less than 60%. The rubber composition described in . 3 Weight ratio of component (A) to component (B) is 25-75:75-25
The rubber composition according to claim 1. 4. The rubber composition according to claim 1, wherein component (C) is natural rubber. 5. Claim 1 in which the component (C) is a polyisoprene rubber having a cis-1,4-bond content of 85% or more.
The rubber composition described in . 6 Component (A): Styrene-butadiene copolymer with a styrene content of 10 to 60% by weight and a vinyl bond content of the butadiene moiety of 25% to less than 60%, (B) component: A vinyl bond content of 25 to 95%. % polybutadiene (C) component: 1 selected from natural rubber, polyisoprene, polybutadiene or styrene-butadiene copolymer with a styrene content of 0 to 60% by weight and a vinyl bond content of the butadiene portion of 1 to 20%. The raw material is a rubber-like conjugated diene polymer with a weight ratio of component (A) and component (B) of 20 to 80:
80-20, the weight ratio of the total amount of component (A) and component (B) to component (C) is 100-25:0-75, and further, component (D): reinforcing agent is added to the raw material rubber. Component (E): A vulcanizing rubber composition containing a vulcanizing agent.