JPS6268842A - Acrylic rubber composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition having high productivity and excellent compression set and suitable as various hose materials, sealing materials, etc., by compounding an acrylic rubber containing a specific crosslinking monomer with a specific amount of an organic peroxide. CONSTITUTION:The objective composition can be produced by compounding (A) 100pts.(wt.) of an acrylic rubber composed of (A1) 60-99.9(wt)%, preferably 80-99.9% one or more compounds selected from alkyl acrylate (e.g. methyl acrylate) and alkoxyalkyl acrylate (e.g. methoxyethyl acrylate), (A2) 0.1-20%, preferably 1-10% unsaturated carboxylic acid ester containing dihydrodicyclopentenyl group (e.g. dihydrodicyclopentenyl acrylate) and (A3) 0-20% one or more compounds selected from other monovinyl compound and monovinylidene (unsaturated) compound (e.g. styrene) with (B) 0.5-10pts. of an organic peroxide [e.g. 1,3-bis(t-butylperoxyisopropyl)benzene].

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an acrylic rubber composition. More specifically, it relates to an acrylic rubber composition that has excellent compression set and productivity.

[Conventional technology]

Acrylic rubber is a nidistomer whose main component is acrylic ester. Since the acrylic ester, which is the main chain, does not have a double bond, it has conventionally been carried out to copolymerize a crosslinking monomer that serves as a crosslinking point.゛As crosslinking monomers, halogen group-containing compounds such as vinyl chloroacetate, chloroethyl vinyl ether, allyl chloroacetate, epoxy group-containing compounds such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, dicyclopentadiene, ethylidene norbornene, etc. It is known to copolymerize diene compounds. The acrylic rubber containing the crosslinking monomer of Kotaru et al. is generally vulcanized with amines, ammonium salts, potassium sulfur, and sulfur. (Journal of the Japan Rubber Association Vol. 53, p. 367 (1980), Development of high-performance elastomers, Polymer Technology Research Institute, Taisei Publishing, p. 273, etc.) Acrylic rubber vulcanizates have heat resistance, ozone resistance, oil resistance, etc. Because of its excellent properties, it is used in oil seals, O-rings, gaskets, gaskets, automobile hoses, etc. However, it requires secondary vulcanization, resulting in poor productivity, and improvements are desired.

(rDevelopment of high-performance elastomer) Polymer Technology Research Kinshi,
(Taiseisha, p. 273) [The problem that the invention aims to solve] As a result of intensive studies on acrylic rubber compositions, the present inventors found that acrylic rubber containing a specific crosslinking monomer and organic peroxide It has been found that a composition consisting of the following has improved productivity, which is a drawback of conventional acrylic rubber, and also has excellent compression set.

[Means for solving the problem] That is, an acrylic rubber composition containing 100 parts by weight of acrylic rubber having the following monomer composition and 0.5 to 10 parts by weight of an organic peroxide does not require secondary vulcanization. It was found that productivity was good and compression set was excellent.

(A) 60 to 99.9% by weight of at least one compound among acrylic acid alkyl esters and acrylic acid alkoxyalkyl esters (B) 0.1 to 20% by weight of dihydrodicyclopentenyl group-containing esters of unsaturated carboxylic acids ( C) At least one compound among other monovinyl, monovinylidene, and monovinylene unsaturated compounds 0
~20% by weight In the component (A) in the acrylic rubber used in the present invention, the acrylic acid ester is 1, for example, methyl acrylate,
Ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, cyanoethyl acrylate, etc., and as an acrylic acid alkoxyalkyl ester. Examples include methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, and ethoxypropyl acrylate, and one or more of these can be used. The content of component (A) is 60 to 99.9% by weight, preferably 80 to 9% by weight.
It is 9.9% by weight. If the amount of component (A) is less than 60% by weight, the resulting acrylic rubber becomes hard, which is not preferable. Moreover, if it exceeds 99.9% by weight, the resulting acrylic rubber will have poor tensile strength, which is not preferable. The dihydrodicyclopentenyl group-containing ester of unsaturated carboxylic acid as component (B) is dihydrodicyclopentenyl acrylate (Cl(,=CH-Co).

(h), dihydrodicyclopentenyl methacrylate, dihydrodicyclopentenyl itaconate, dihydrodicyclopentenyl maleate, dihydrodicyclopentenyl fumarate, dihydrodicyclopentenyloxyethyl acrylate, dihydrodicyclopentenyloxyethyl methacrylate, itacon Examples include dihydrodicyclopentenyloxyethyl acid, dihydrodicyclopentenyloxyethyl maleate, dihydrodicyclopentenyl fumarate, and dihydrodicyclopentenyl acrylate and dihydrodicyclopentenyloxyethyl acrylate are particularly preferred. The content of component (B) is 0.1 to 20% by weight
, more preferably 1 to 10% by weight.

If the amount of component (B) exceeds 20% by weight, the heat resistance will deteriorate, which is undesirable, and if the amount is less than 0.1% by weight, the resulting acrylic rubber will have poor tensile strength. Specific compounds of component (C) include, for example, styrene, vinyltoluene, α-methylstyrene, vinylnaphthalene, halogenated styrene, acrylonitrile, methacrylonitrile,
Acrylic acid esters of aromatic and alicyclic alcohols such as acrylamide, N-methylolacrylamide, vinyl acetate, vinyl chloride, vinylidene chloride, and cyclohexyl acrylate, benzyl acrylate, etc., as well as methacrylic acid, itaconic acid, fumaric acid, maleic acid. Examples include esters of unsaturated carboxylic acids such as acids and lower saturated alcohols. Note that component (C) is used as necessary, and it is appropriate that the amount of the component does not exceed 20% by weight.

Examples of organic peroxides include di-t-butyl peroxide,
Dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,3-bis(t
Although conventional organic peroxides such as 1,3-bis-butylperoxyisopropyl)benzene can be used, 1,3-bis-butylperoxyisopropylbenzene is preferred.

The amount of organic peroxide is rubber 1. 0.5 to 1 part by weight of JO is used per part by weight of O0. If it is less than 0.5 parts by weight, no vulcanizing effect will be observed, and if it exceeds 10 parts by weight, it will have an adverse effect on the physical properties of the vulcanizate.

Moreover, the productivity improvement effect and compression set improvement effect of the present invention can only be achieved by using component (B) as a crosslinking monomer and combining it with an organic peroxide.

In addition to this, the acrylic rubber composition also contains vulcanization aids, reinforcing agents,
Additives such as anti-aging agents, stabilizers, plasticizers, pigments, etc. can be blended as appropriate.

Vulcanization is generally carried out at 14.0°C or higher after mixing the organic peroxide described in Section 2 and the above additives as necessary using a commonly used mixing method such as open roll mixing, Banbury mixer mixing, or intermixer mixing. This is carried out by heating to a temperature of 1 to 40° C. or higher, if necessary.

Next, an example will be described.

Incidentally, all percentages and parts shown in the examples mean percentages and parts by weight.

〔Example〕

Examples 1 to 5, Comparative Example 1.3γ5.

100 parts of monomer mixture, 4 parts of sodium lauryl sulfate,
After 0.2 parts of potassium persulfate was charged into an iron vessel purged with nitrogen and polymerized at 50° C. for 15 to 20 hours, the reactant was taken out and steam was blown in to remove unreacted monomers. The acrylic rubber latex thus obtained is added to a 0.25% calcium chloride aqueous solution and coagulated (at this time, calcium chloride with a rubber content of about 5% is used).The coagulated product is thoroughly washed with water and It was dried for 3-4 hours at <0>C.

The composition of the acrylic rubber obtained as described above is shown in Table 1.

To 100 parts of the acrylic rubber, 1.0 parts of stearic acid, 50 parts of carbon black, and 1 * 3- in the amounts shown in Table -■.
bjs -(t-butylperoxyisopropyl)benzene (manufactured by Kayaku Nooney Co., Ltd., Parryoku Dox 14/40
, hereinafter abbreviated as Parriki Dox) and N,N'-m-phenylene cymaleimide (manufactured by Iruuchi Shinko ■, Parnock PM, hereinafter abbreviated as Parnock PM) were kneaded with a roll at a pressure of 10
180°C using a 0kg/afG vulcanization press11. .

After vulcanization for 15 minutes, the properties of the vulcanizate were measured using conventional methods.

The results are shown in Table-■.

Example 6.7, Comparative Example 7 Using acrylic rubber with the composition shown in Table ■, the force □
- 100 parts of clay (Tsukiji Clay R, T, manufactured by Vanderbilt), respectively, 50 parts of bomb black;
The same procedure as in Example 1 was carried out, except that the amount of silica (Nibsil VN□, manufactured by Nippon Silica) was changed to 50 parts, and the amounts of Parriki Dox and Parnock PM were changed.

Comparative Example 6 11.8 parts of Parkadoc, 3.2 parts of Parnoc PM, 0.4 part of sulfur, 0.75 parts of vulcanization accelerator TT, 5 parts of zinc oxide
．． The same procedure as in Example 1 was carried out except that the amount was changed to 0 parts.

〔Effect of the invention〕

According to the present invention, it has been found that a composition of an acrylic rubber and an organic peroxide using a dihydrodicyclopentenyl group-containing ester of an unsaturated carboxylic acid as a crosslinking Ql □ substance has excellent productivity and compression set. .

Taking advantage of these good physical properties, oil cooler hoses,
Various hose materials such as Emer-duct hoses, power steering hoses, control hoses, intercooler hoses, torque converter hoses, oil return hoses, heat-resistant hoses, bearing seals, bulk stem seals, various oil seals, O-rings, packings, gaskets, etc. Used for sealing materials, various diaphragms, rubber plates, belts, oil level gauges, hose masking, coating materials such as pipe insulation materials, and rolls.

Since the acrylic rubber composition of the present invention has good oil resistance and heat resistance, by mixing it with various rubbers or resins, the oil resistance and heat resistance of the rubber or resin can be improved. At this time, it is also effective to powder the acrylic rubber and mix it.

Patent applicant: Japan Synthetic Rubber Co., Ltd. Procedural amendment (voluntary)

Claims (1)

[Claims] (1) (A) 60 to 99.9% by weight of at least one compound selected from acrylic acid alkyl esters and acrylic acid alkoxyalkyl esters, (B) 0.1 to 99.9% by weight of dihydrodicyclopentenyl group-containing esters of unsaturated carboxylic acids. 100 parts by weight of acrylic rubber having a monomer composition consisting of 20% by weight, and (C) 0 to 20% by weight of at least one compound selected from other monovinyl, monovinylidene and monovinylene unsaturated compounds; An acrylic rubber composition containing 0.5 to 10 parts by weight of an organic peroxide.