JPH0689180B2 - Light color rubber composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a light color rubber composition.

Conventional technology Synthetic rubbers containing halogen atoms in the molecule, especially polychloroprene rubber and polychlorosulfonated polyethylene rubber, are dehydrochlorinated during vulcanization, and the rubber becomes black. A so-called light-colored mixture is used so as to conceal blackening at the time of vulcanization by mixing a large amount of a pigment having a strong hiding power such as a pigment.

Problems to be Solved by the Invention However, the halogen-containing rubber bright color compounding with a large amount of the pigment as described above, on the other hand, reduces the tensile strength, elongation, module, etc. of the vulcanized rubber, and also vulcanizes the vulcanized rubber. The member that comes into contact with the rubber product causes discoloration of the pigment and also increases the price of the vulcanized rubber product. On the other hand, even if the slight blackening at the time of vulcanization is admitted and the compounding amount of the pigment is limited to a small amount, the degree of blackening is significantly different due to the thermal history due to the temperature and time of vulcanization, and Since the variation is large, it is inferior in commercial value and difficult to put into practical use.

The present inventors have conducted extensive studies to solve the above-mentioned problems in the light-colored compounding of conventional polychloroprene rubber and polychlorosulfonated polyethylene rubber, and as a result, have found that the synthetic rubber containing a halogen atom does not contain a halogen atom in a diolefin system. By compounding a rubber, it has been found that it is possible to effectively prevent blackening during vulcanization of the halogen-containing rubber while suppressing the compounding amount of the pigment to a small amount, which has led to the present invention. .

The light-colored rubber composition according to the present invention is a light-colored compound composition containing a halogen-containing rubber polymer selected from polychloroprene rubber and polychlorosulfonated polyethylene rubber. 3 to 40% by weight of the combined product is at least one kind selected from the group consisting of natural rubber, polyisoprene rubber, acrylonitrile-butadiene copolymer rubber and styrene-butadiene copolymer rubber, and does not contain halogen in the molecule. It is characterized in that it is substituted with a polymer.

In the light-colored rubber composition according to the present invention, the halogen-containing rubber polymer contains at least one selected from the group consisting of natural rubber, polyisoprene rubber, acrylonitrile-butadiene copolymer rubber and styrene-butadiene copolymer rubber. A diolefin-based rubber polymer containing no halogen in the molecule is blended. These diolefin-based rubber polymers are blended alone or as a mixture of two or more.

According to the present invention, by replacing 3 to 40% by weight of a halogen-containing rubber polymer selected from polychloroprene rubber and polychlorosulfonated polyethylene rubber with the above-mentioned diolefin rubber, a black color at the time of vulcanization is obtained. Can be effectively prevented. When the substitution amount of the diolephin-based rubber in the halogen-containing rubber is less than 3% by weight, blackening at the time of vulcanization cannot be avoided. On the other hand, when the amount exceeds 40 parts by weight, there is no discoloration during vulcanization, but the diolefin rubber forms a continuous phase and loses the properties of the halogen-containing rubber, so there is no reason to use such a rubber polymer. Also, various rubber physical properties are deteriorated.

In the present invention, the halogen-containing rubber polymer may be vulcanized by sulfur vulcanization or metal oxide vulcanization. In either case, blackening during vulcanization can be effectively prevented.

Further, in the present invention, the halogen-containing rubber polymer,
It is needless to say that a compounding agent that is usually compounded, for example, a rubber compounding agent such as a reinforcing agent, a filler, an oil, an antioxidant, a vulcanizing agent, and a vulcanization accelerator may be compounded in an appropriate amount.

The reason why the blackening at the time of vulcanization is prevented by the blending of the light-colored rubber according to the present invention is not necessarily clear, but hydrogen chloride produced by dehydrochlorination has a double bond in the molecule of the diolefin rubber. It seems to be to add to. However, the present invention is in no way limited by the mechanism of blackening prevention.

As described above, according to the present invention, by replacing 3 to 40% by weight of the polymer of the halogen-containing rubber selected from the polychloroprene rubber and the polychlorosulfonated polyethylene rubber with the diolefin rubber. In addition, it is possible to stably prevent blackening during vulcanization by adding a small amount of pigment, and the vulcanized rubber product obtained has a small amount of pigment, and therefore a halogen-containing rubber is used. It retains excellent physical properties. Furthermore, since a large amount of pigment is not used, a vulcanized rubber product can be manufactured at low cost, and
In such a vulcanized rubber product, pigment discoloration does not occur even when it comes into contact with an article.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 Sulfur vulcanization type polychloroprene rubber shown in Table 1 Acrylonitrile-butadiene copolymer rubber was compounded in various amounts in a light-colored composition and heated at 150 ° C. for 30 minutes under vulcanization conditions A
STM2mm slab was vulcanized. The degree of discoloration is shown in Table 1.
The degree of discoloration is a 10-step rating, with 10 for the 100% polychloroprene rubber compound and 1 for the 100% NBR compound. It depends on the price (the same applies below).

Example 2 Sulfur-vulcanized polychloroprene rubber shown in Table 2 was mixed with a light-colored acrylonitrile-butadiene copolymer rubber (N230S manufactured by Japan Synthetic Rubber Co., Ltd.), styrene-butadiene rubber (SBR manufactured by Japan Synthetic Rubber Co., Ltd.). 1502), isoprene rubber (JSR IR 2200 manufactured by Japan Synthetic Rubber Co., Ltd.) or natural rubber 1
0 parts by weight was compounded and an ASTM 2 mm slab was obtained under the same conditions as in Example 1. The degree of discoloration is shown in Table 2.

Thus, it is considered that the reason why the effects are different at the same compounding amount is that it depends on the double bond amount of the diolefin rubber polymer that traps hydrogen chloride generated during vulcanization.
For example, as compared with acrylonitrile-butadiene copolymer rubber and styrene-butadiene copolymer rubber, polyisoprene rubber and natural rubber have a large amount of double bonds when the compounding amount is the same, resulting in blackening. Will be excellent in the effect of.

Example 3 Metal oxide vulcanization type polychloroprene rubber shown in Table 3 Acrylonitrile-butadiene copolymer rubber 10 in light color compounding
Parts by weight were compounded and vulcanized into an ASTM 2 mm slab under the same conditions as in Example 1. The degree of discoloration is shown in Table 3.

Example 4 Polychlorosulfonated polyethylene rubber shown in Table 4 Acrylonitrile-butadiene copolymer rubber 10 in light color compounding
Parts by weight were compounded and vulcanized into an ASTM 2 mm slab under the same conditions as in Example 1. The degree of discoloration is shown in Table 4.

Claims (1)

[Claims] 1. A light color compounding composition containing a halogen-containing rubber polymer selected from polychloroprene rubber and polychlorosulfonated polyethylene rubber, wherein 3 to 40% by weight of the halogen-containing rubber polymer is natural rubber or polyisoprene. It is characterized in that it is substituted with a diolefin-based rubber polymer containing no halogen in the molecule of at least one kind selected from the group consisting of rubber, acrylonitrile-butadiene copolymer rubber and styrene-butadiene copolymer rubber. Light color rubber composition.