JPH0525355A - Chloroprene rubber composition - Google Patents

Abstract

PURPOSE:To provide a chloroprene rubber composition excellent in tensile characteristics. CONSTITUTION:A chloroprene rubber composition is obtained by blending 100 pts.wt. chloroprene rubber with >=10 pts.wt. methacrylic acid, 0 to (X) pts.wt. (X denotes pts.wt. of an alpha,beta-unsaturated carboxylic acid and/or alpha,beta-unsaturated carboxylic acid derivatives in an amount so as to be equimolar with pts.wt. of the methacrylic acid used for blending other than the methacrylic acid) and >=5 pts.wt. zinc compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention shows excellent tensile properties by vulcanization, and boots, belts, hoses,
The present invention relates to a chloroprene rubber composition suitable as a raw material for anti-vibration rubbers and the like.

[0002]

2. Description of the Related Art Chloroprene rubber is used as a raw material for rubber products in various fields because it has a relatively balanced physical property among synthetic rubbers. However, with recent advances in science and technology, the demands on the quality and physical properties of rubber molded products have become higher and higher, and further improvements in physical properties are required for the raw material rubber and rubber compositions. One of these requirements is tensile strength,
There are improvements in tensile properties such as tensile stress. It is generally known that a reinforcing agent such as carbon black is added as a method for improving the tensile properties of rubber products. However, the addition of carbon black has the drawback of increasing the Mooney viscosity of the formulation and degrading processability.

As a method for avoiding such a defect, Japanese Patent Laid-Open No. Sho 60-92237 discloses that the amount of the rubber polymer is about 100 parts by weight per 100 parts by weight.
25-85 zinc dimethacrylate having about 3.7 ~5.4 m ² / g or more of the surface area of the parts and the composition is disclosed which contains a curing effective amount of a peroxide curing agent. However, this method uses zinc dimethacrylate,
It differs from the present invention in that a peroxide curing agent is essential, and the effect of improving tensile properties cannot be said to be sufficient.

Further, JP-A-2-235946 also discloses a rubber composition obtained by adding 0.1 to 10 parts by weight of a metal acrylate and / or a metal methacrylate to 100 parts by weight of a chlorine-containing rubber. However, the present invention is intended for early vulcanization of the rubber composition and has a different purpose from the present invention. Further, it is clear that the content is clearly different from that of the present application in that the metal salt of methacrylic acid is used.

JP-A-1-306441 and JP-A-1-306443 disclose that an ethylenically unsaturated nitrile-conjugated diene copolymer rubber or an ethylenically unsaturated nitrile-conjugated diene highly saturated rubber contains a zinc compound. A rubber composition containing methacrylic acid, methacrylic acid and an organic peroxide is disclosed. However, the present invention differs from the present invention in that the raw material rubber has a nitrile group and that an organic peroxide must be blended as an essential component. That is, since the present invention can be crosslinked with various crosslinking agents not limited to peroxides, there is an advantage that a wide variety of rubber compounding chemicals other than the essential components of the present invention can be selected and compounded.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a chloroprene rubber composition which is excellent in tensile properties and has a good balance of other physical properties.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that chloroprene rubber contains methacrylic acid and α, β-unsaturated carboxylic acids other than methacrylic acid (hereinafter simply referred to as methacrylic acid). By mixing α, β-unsaturated carboxylic acid) and / or α, β-unsaturated carboxylic acid derivative and zinc compound, a chloroprene rubber compound having excellent tensile properties such as tensile strength and tensile stress can be obtained. The present invention has been completed and the present invention has been completed.

That is, the present invention relates to chloroprene rubber 100.
10 parts by weight or more of methacrylic acid, and 0 to X parts by weight of α, β-unsaturated carboxylic acid and / or α, β-unsaturated carboxylic acid derivative (where X is the weight of methacrylic acid used for compounding). Parts, which represent an equimolar amount of α, β-unsaturated carboxylic acid and / or α, β-unsaturated carboxylic acid derivative), and 5 parts by weight or more of a zinc compound.
The present invention provides a chloroprene rubber composition having excellent tensile properties.

The chloroprene rubber used in the present invention is a polymer obtained by polymerizing 2-chloro-1,3-butadiene alone, or 2-chloro-1,3-butadiene and 2-chloro-1,3.
-It is copolymerized from one or more monomers copolymerizable with butadiene. 2-chloro-
Examples of the monomer copolymerizable with 1,3-butadiene include styrene, acrylonitrile, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, 2,
Examples thereof include 3-dichloro-1,3-butadiene. Further, the method of polymerization or copolymerization is not particularly limited, and any method such as emulsion polymerization, suspension polymerization and solution polymerization can be used. The form of polymerization is not particularly limited and may be ionic polymerization or radical polymerization.

The amount of methacrylic acid used in the present invention is
The amount is 10 parts by weight or more, preferably 10 to 50 parts by weight, based on 100 parts by weight of chloroprene rubber. When the amount is less than 10 parts by weight, the effect of improving the tensile properties is insufficient, and when it exceeds 50 parts by weight, the elongation at break is lowered, which is a practical problem.

The amount of the α, β-unsaturated carboxylic acid and / or α, β-unsaturated carboxylic acid derivative used in the present invention is 0 to X per 100 parts by weight of the chloroprene rubber.
Parts by weight (where X is a molar equivalent of α, β-unsaturated carboxylic acid and / or α, with the parts by weight of methacrylic acid used in the formulation)
It is a part by weight of β-unsaturated carboxylic acid derivative). α, β-
When the blending mole number of the unsaturated carboxylic acid and / or the α, β-unsaturated carboxylic acid derivative exceeds the blending mole number of methacrylic acid, the effect of improving the tensile properties becomes small. Examples of the α, β-unsaturated carboxylic acid include acrylic acid, crotonic acid, cinnamic acid, maleic acid and the like.
Examples of α, β-unsaturated carboxylic acid derivatives include alkyl esters, alkenyl esters, aralkyl esters, cycloalkyl esters, alkyl amides of acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, maleic acid, etc.
Examples thereof include alkenyl amides, aralkyl amides, aryl amides, maleimides such as maleimides, N-alkyl maleimides and phenylene bismaleimides, and maleic anhydride.

The zinc compound used in the present invention is 5 parts by weight or more, preferably 0.5 Y parts by weight or more per 100 parts by weight of chloroprene rubber (where Y is a zinc compound having an equimolar amount to the parts by weight of the methacrylic acid blended). Parts by weight). Examples of the zinc compound include zinc oxide and zinc carbonate.

The composition of the present invention is usually used by vulcanization molding, but the vulcanizing agent or vulcanization accelerator that can be used at that time is not particularly limited, and a vulcanizing agent or vulcanizing agent for chloroprene rubber can be used. Sulfur accelerators such as sulfur, salicylic acid, thiourea compounds, guanidine compounds, thiuram compounds, thiazole compounds and the like can be used.

In the composition of the present invention, other kinds of polymers and various compounding agents for rubber which are usually used can be added within a range that does not impair the effects of the present invention. Examples of other polymers include natural rubber (NR) and isoprene rubber (I
R), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene rubber (EPDM), butyl rubber (II
R), chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CPE), polyvinyl chloride (PVC)
Etc. Examples of commonly used compounding agents for rubber include fillers, softeners, plasticizers, antiaging agents, processing aids, acid acceptors and the like.

As a method of blending the composition of the present invention,
Any method generally used in the rubber processing field can be used, and examples thereof include a mixing roll, a Banbury mixer, various kneaders, and an extruder having a kneading action. The kneading is preferably carried out by previously adding a zinc compound to chloroprene rubber, kneading the mixture to disperse it sufficiently uniformly, and then methacrylic acid, α, β-unsaturated carboxylic acid and / or α, β-unsaturated carboxylic acid derivative. A method of adding and kneading is preferable.

The vulcanization condition of the composition of the present invention is not particularly limited, but it is usually 100 to 100 at the same time as pressure molding by a mold, extrusion molding, injection molding, calender molding or in a vulcanization tank. It can be vulcanized by heating at 200 ° C for several seconds to several hours using an electric heater, an oil heater, high temperature steam, hot air, infrared rays, high frequency waves, etc.

[0017]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” means “parts by weight” unless otherwise specified.

Examples 1 to 10 Chloroprene rubber is coated with zinc oxide, methacrylic acid, α, β-
Unsaturated carboxylic acid and / or α, β-unsaturated carboxylic acid derivative and other compounding ingredients were kneaded and vulcanized in the ratios shown in Table 1 to obtain a vulcanized chloroprene rubber composition. The procedure of kneading and vulcanization is as follows. Raw rubber was wrapped around a mixing roll whose surface temperature was adjusted to 50 ° C., and a zinc compound was added and kneaded. After the zinc compound is sufficiently dispersed, methacrylic acid, α, β-unsaturated carboxylic acid and / or α,
The β-unsaturated carboxylic acid derivative was added and kneaded. After adding a vulcanizing agent and / or a vulcanization accelerator and thoroughly kneading,
Rolled into sheets. Some of the resulting sheets are 15
Press vulcanization at 0 ° C. for the time shown in Table 1 to obtain a vulcanized product,
Used for physical property test. The Mooney viscosity of the unvulcanized product was measured from the remaining portion. The physical property test is JIS K6.
300, K6301 was performed.

Comparative Example 1 The procedure of Example 1 was repeated except that methacrylic acid was not added. Comparative Example 2 The procedure of Example was repeated except that acrylic acid was used instead of methacrylic acid. Comparative Example 3 Example 3 was repeated except that magnesium oxide was used instead of the zinc compound. Comparative Example 4 Instead of using methacrylic acid and a zinc compound, zinc methacrylate was used. Others were the same as in the example. Comparative Example 5 The same procedure as in Example was carried out using carbon black which is a general reinforcing agent. The above results are shown in Table 1.

[0020]

[Table 1]

A description of the annotations in Table 1. 1) Denka Chloroprene D manufactured by Denki Kagaku Kogyo Co., Ltd.
CR-35 2) Asahi Carbon Co., Ltd. Asahi # 50 3) Nippon Oil & Fats Co., Ltd. 4) Kawaguchi Chemical Industry Co., Ltd. Axel 22-S 5) 2,2'-azobis (isobutyro) (Nitrile)

From the comparison between Examples and Comparative Examples 1 to 3, methacrylic acid, α, β-unsaturated carboxylic acid and / or α,
It can be seen that by blending the β-unsaturated carboxylic acid derivative and the zinc compound, a vulcanized product excellent in 100% tensile stress and tensile strength can be obtained. From the results of Comparative Example 4 and Example 1,
It can be seen that the tensile properties are better when the methacrylic acid and the zinc compound are blended than when the zinc methacrylate is blended. From the comparison between Comparative Example 5 and Example, methacrylic acid, α,
The blend obtained by blending β-unsaturated carboxylic acid and / or α, β-unsaturated carboxylic acid derivative, zinc compound should show better workability and tensile properties than those blended with carbon black. I understand.

[0023]

As described above, by adding methacrylic acid, α, β-unsaturated carboxylic acid and / or α, β-unsaturated carboxylic acid derivative, and zinc compound to chloroprene rubber, excellent tensile properties can be obtained. It is possible to obtain a chloroprene rubber composition which gives a vulcanized product and can be suitably used for various purposes.

Claims (1)

Claims: 1. 100 parts by weight of chloroprene rubber, 10 parts by weight or more of methacrylic acid, and α, β- other than methacrylic acid.
Unsaturated carboxylic acid and / or α, β-unsaturated carboxylic acid derivative 0 to X parts by weight (where X is an α, β-unsaturated component other than methacrylic acid that is equimolar to the parts by weight of methacrylic acid used for compounding) Carboxylic acid and / or α, β-unsaturated carboxylic acid derivative by weight), and zinc compound 5
A chloroprene rubber composition containing at least 1 part by weight.