JPH0692507B2 - Vulcanizing rubber composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a rubber composition having good mechanical properties.

b. Conventional Technology A method of bringing out the performance not obtained by a single elastomer by blending two or more elastomers has been practiced for a long time.

The blending method is also used for the purpose of improving workability and reducing raw material costs.

Typical examples of the composition obtained by such a method include a blend composition of styrene-butadiene rubber (hereinafter abbreviated as SBR) and polybutadiene rubber (hereinafter abbreviated as BR) as a material for a tire tread, and a tire. And a blend composition of ethylene-propylene-non-conjugated diene rubber (hereinafter abbreviated as EPDM) as a material for the sidewall of the above.

However, in the case of a blended rubber of a highly saturated rubber and a highly unsaturated rubber, the mechanical properties of the blended rubber generally tend to be lowered by blending because there is a marked difference in the vulcanization rate of both. Met.

In particular, EPDM and acrylonitrile-butadiene rubber (below
In the case of blending with NBR), the compatibility is poor due to the difference in vulcanization speed and the difference in the characteristics, and the filler, vulcanizing agent, and vulcanization accelerator are not evenly dispersed in both rubbers. Since the so-called uneven distribution is likely to occur, it is unavoidable that the mechanical properties are greatly deteriorated.

To remedy these drawbacks, RT Morrissery
Method of halogenating EPDM (Rubber Chem.Technal., 4
4, 1025 (1971)). In addition RPMastromatteo et al., A method using a dialkyl geo carbamate salts and tetraalkyl thiuram disulfide having an alkyl group of a long chain as a vulcanization accelerator (Rubber Chem.Technal., 44, 1025 (197
1)) is proposed.

In addition, Hashimoto et al. Made EPDM having pendant sulfur by reacting EPDM with sulfur or a vulcanization accelerator, and then blending with other rubber (Japan Rubber Association Journal, 49 , 236, 246 (1976)).
Is proposed.

c. Problems to be Solved by the Invention However, in these methods, when the highly unsaturated diene rubber is a natural rubber having low polarity, SBR, BR, etc. In that case, the effect was small and the mechanical properties of the blended rubber tended to deteriorate significantly, making it unusable for practical use.

As a result of intensive studies in view of these points, the present inventors have produced a rubber composition having good mechanical properties by dynamically vulcanizing a blend rubber of a highly saturated rubber and a highly unsaturated diene rubber. Based on this finding, the present invention has been completed.

d. Means for Solving the Problems That is, the present invention is a rubber composition comprising 20 to 80 parts by weight of a highly saturated rubber and 80 to 20 parts by weight of a highly unsaturated diene rubber,
By dynamically vulcanizing the highly saturated rubber and the highly unsaturated diene rubber at 140 to 170 ° C while kneading, the extractable partial amount when the highly saturated rubber is extracted at room temperature using a solvent capable of dissolving Is 90% by weight or more based on the total amount of highly saturated rubber,
It is characterized by being vulcanized so that the extractable partial amount when extracted at room temperature with a solvent capable of dissolving highly unsaturated diene rubber is 10% by weight or less based on the total amount of highly unsaturated diene rubber. A rubber composition for vulcanization is provided.

Examples of the highly saturated rubber, ethylene-propylene copolymer rubber, ethylene-propylene-non-conjugated diene copolymer rubber, acrylic rubber, silicone rubber, fluororubber, epichlorohydrin rubber, chlorosulfonated polyethylene,
Examples include chlorinated polyethylene and butyl rubber.

As the highly unsaturated diene rubber, natural rubber, polyisoprene rubber, polybutadiene rubber, vinyl allene such as styrene or vinyl pyridine, acrylonitrile,
Mention may be made of copolymers of 1,3-butadiene and isoprene with methacrylonitrile, isobutylene acrylate and methacrylate.

The compounding ratio of the highly saturated rubber and the highly unsaturated diene rubber in the rubber composition of the present invention is 20 to 80 parts by weight / 80 to 20% by weight.

When the compounding amount of the highly saturated rubber is less than 20 parts by weight and the compounding amount of the highly unsaturated diene rubber exceeds 80 parts by weight, thermoplasticity cannot be imparted to the composition after dynamically vulcanizing, and processing is difficult. It will be difficult.

Further, if the amount of the highly saturated rubber compounded exceeds 80 parts by weight and the amount of the highly unsaturated diene rubber compounded is less than 20 parts by weight, the mechanical properties of the blended product deteriorate.

The rubber composition of the present invention is obtained by dynamically vulcanizing at 140 to 170 ° C. while kneading the above highly saturated rubber and highly unsaturated diene rubber.

The above "dynamic vulcanization" is, for example, U.S. Pat.
No. 3758643, No. 3806558, No. 4104210 and the like are introduced as a method for producing a thermoplastic composition in a blend of rubber and a thermoplastic polyolefin.

That is, the rubber composition of the present invention, while kneading the highly saturated rubber and the highly unsaturated diene rubber and the vulcanizing agent using a conventional kneading processing device, for example, a Banbury mixer, a Brabender mixer, a roll machine, a mixing extruder and the like. It is produced by dynamically vulcanizing.

The kneading temperature at this time is 140 to 170 ° C.

If the kneading temperature is lower than 140 ° C, the rubber composition is slowly vulcanized, and it requires a long time for kneading. If the kneading temperature is higher than 170 ° C, the vulcanization is too fast and the mechanical strength is reduced.

The kneading time varies depending on the kneading temperature of the type of the vulcanizing agent used, but is preferably 3 minutes to 30 minutes.

If it is less than 3 minutes, the vulcanization is insufficient, and if it exceeds 30 minutes, the deterioration of the rubber becomes severe.

The vulcanizing agent used may be any vulcanizing agent applicable to the vulcanization of diene rubbers, such as sulfur / accelerator systems, peroxides,
A quinoid or methylolphenol resin can be used.

The dynamic vulcanization of the present invention is such that the extractable partial amount when extracted at room temperature using a solvent capable of dissolving a highly saturated rubber is 90% by weight or more based on the total amount of the highly saturated rubber, and dissolves the highly unsaturated diene rubber. It is carried out such that the extractable partial amount when extracted at room temperature with a possible solvent is 10% by weight or less based on the total amount of the highly unsaturated diene rubber.

When the extractable partial amount when the highly saturated rubber is extracted at room temperature with a solvent capable of dissolving the highly saturated rubber is less than 90% by weight of the total amount of the highly saturated rubber, thermoplasticity cannot be imparted to the rubber composition of the present invention.

If the extractable partial amount of the highly unsaturated diene rubber extracted at room temperature with a solvent capable of dissolving exceeds 10% by weight of the total amount of the highly unsaturated diene rubber, the effect of improving the mechanical properties becomes insufficient.

The solvent capable of dissolving the highly saturated rubber or the highly unsaturated diene rubber used in the present invention is a solvent capable of dissolving the unvulcanized rubber before vulcanization of these rubbers at room temperature.

In such a solvent, examples of those capable of dissolving non-polar rubber such as natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer, ethylene-propylene copolymer are toluene and cyclohexane. And the like.

Further, examples of the one capable of dissolving rubber having a strong polarity such as acrylic rubber and acrylonitrile-butadiene copolymer include solvents such as methyl ethyl ketone.

In addition, as long as it can dissolve a highly saturated rubber or a highly unsaturated diene rubber, the extractable partial amount when using the solvent as described above is the same. Is not particularly limited.

In addition to the highly saturated rubber and the highly unsaturated diene rubber of the present invention, a vulcanizing agent may be added to the rubber composition of the present invention, and further, carbon black, a plasticizer, a process oil, an antioxidant, etc. It is also possible to add a rubber compounding agent.

The rubber composition for vulcanization of the present invention obtained by carrying out dynamic vulcanization is because the highly saturated rubber is not or hardly vulcanized, that is, extracted at room temperature with a solvent capable of dissolving the highly saturated rubber. Since the extractable part amount is 90% by weight or more, it is sufficiently thermoplastic, and a vulcanizing agent is further added and mixed using a roll machine, a Banbury mixer, etc. For example, it can be vulcanized and molded by a press machine, an injection steam can or the like.

Further, the composition of the present invention comprises an olefin polymer such as polypropylene and polyethylene, a styrene polymer such as ABS, high styrene resin, AES, ABS, SB, SBS, SI, SIS, SEBS, or a vinyl chloride polymer. It can be blended with a molecular substance and, if necessary, dynamically crosslinked to be used as a thermoplastic elastomer for blow molding.

In addition, depending on the purpose, these blends can be vulcanized and molded by an ordinary static vulcanizing device such as a pressing machine or an injection steam can.

e. Examples Next, examples of the present invention will be shown, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

In the following Examples and Comparative Examples,% is% by weight
Is the meaning of.

The physical properties of the compositions obtained in the following examples and comparative examples were evaluated mainly according to JIS K 6301.

Examples 1 to 4; Comparative Examples 1 and 2 In accordance with the formulation shown in Table 1, a Brabender mixer was used to dynamically vulcanize while kneading at 150 ° C (oil bath temperature) for 5 minutes.

The obtained mixtures are referred to as rubber mixture-1 to rubber mixture-6, respectively.

Next, a vulcanizing agent was further added to and mixed with the obtained mixture (rubber mixture-1 to 6) according to the formulation shown in Table 2.

The extractable partial amount of the highly unsaturated diene rubber in the rubber mixtures-1 to 6 was calculated from the insoluble content of the highly unsaturated diene rubber in the solvent at room temperature and is shown in Table 3.

For the rubber mixtures-1,2,3,5,6, methyl ethyl ketone was used as the extraction solvent for the highly unsaturated diene rubber,
For rubber mixture-4, toluene was used.

Further, the soluble components (extractable partial amount) at room temperature of the highly saturated rubbers in the rubber mixtures-1 to 6 in the extraction solvent (cyclohexane) were determined and are shown in Table 3.

Comparative Examples 3 and 4 According to the formulation shown in Table 4, kneading was carried out by an ordinary method.

The content of the highly unsaturated diene rubber in the obtained rubber mixture-7,8 insoluble in methyl ethyl ketone was 3 at room temperature.
% And 7%.

That is, the extractable partial amounts of the highly unsaturated diene rubber in the rubber mixture-7,8 were 97% and 93%, respectively.

The soluble content (extractable partial amount) of the highly saturated rubber in the rubber mixture-7 in cyclohexane at room temperature was 94%.

The soluble content (extractable partial amount) of the highly saturated rubber in the rubber mixture-8 in methyl ethyl ketone at room temperature was 91%.

The rubber mixtures-1 to 8 obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were press-vulcanized at 160 ° C for 20 minutes, and the physical properties of the vulcanizates obtained were evaluated.

The results are shown in Table-5.

f. Effect of the Invention According to the present invention, by dynamically vulcanizing the highly saturated rubber and the highly unsaturated diene rubber while kneading, the vulcanization rate of the vulcanization rate at the time of blending the highly saturated rubber and the highly unsaturated rubber It is possible to solve the deterioration in mechanical properties due to the difference and obtain a vulcanizing rubber composition having good mechanical properties.

Further, the rubber composition of the present invention is sufficiently thermoplastic since the highly saturated rubber is not or hardly vulcanized, and can be further vulcanized and molded by the static vulcanization method.

That is, the vulcanizing rubber composition of the present invention is a vulcanizing rubber composition having excellent mechanical strength and has an extremely high industrial utility value.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display area C08L 21:00) (72) Inventor Hironori Matsumoto 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd. (72) Inventor Yasuhiko Takemura 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd. (56) Reference JP-A-57-73031 (JP, A) JP-A- 59-91142 (JP, A) JP-B 42-25763 (JP, B1) JP-B 51-1263 (JP, B2) JP-B 54-3892 (JP, B2)

Claims (3)

[Claims] 1. A rubber composition comprising 20 to 80 parts by weight of a highly saturated rubber and 80 to 20 parts by weight of a highly unsaturated diene rubber, which is obtained by kneading the highly saturated rubber and the highly unsaturated diene rubber.
By dynamically vulcanizing at 0 ~ 170 ℃, the extractable partial amount when extracting at room temperature with a solvent that can dissolve highly saturated rubber is 90% by weight or more based on the total amount of highly saturated rubber, Vulcanization characterized by being vulcanized to such an extent that the extractable partial amount when the unsaturated diene rubber is extracted at room temperature with a solvent capable of dissolving it is 10% by weight or less based on the total amount of the highly unsaturated diene rubber. Rubber composition. 2. The rubber composition for vulcanization according to claim 1, wherein the highly saturated rubber is an ethylene-propylene copolymer rubber. 3. The rubber composition for vulcanization according to claim 1, wherein the unsaturated diene rubber is an unsaturated nitrile-conjugated diene rubber.