JPH05295214A - Rubber composition and vulcanized rubber composition - Google Patents

Abstract

PURPOSE:To provide the vulcanizable rubber composition which is excellent in the oil resistance, heat resistance, cold resistance and compression permanent set and composed of an ethylene-methacrylate ester copolymer rubber and an epichlorohydrin rubber as main components. CONSTITUTION:The rubber composition comprises (A) 30-95 pts.wt., preferably 40-70 pts.wt., of an ethylene-(meth) acrylate ester copolymer rubber [e.g. the copolymer of ethylene, a (meth) acrylate ester and an epoxy group-containing monomer], 70-5 pts.wt., preferably 60-30 pts.wt., of an organic peroxide- vulcanizable epichlorohydrin rubber (e.g. epichlorohydrin-ethylene oxide- acrylglycidyl ether copolymer), the total amount of A and B being 100 pts.wt., and 1-10 pts.wt. of an epoxy group-containing compound, preferably a compound obtained by the condensation reaction of bisphenol A with epichlorohydrin and having an average molecular weight of 300-15000 and an epoxy equivalent of 100-10000, and the vulcanized rubber composition is produced by vulcanizing the composition with an organic peroxide.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a rubber composition and a vulcanized rubber composition. More specifically, the present invention is mainly composed of an ethylene- (meth) acrylic acid ester-based copolymer rubber and epichlorohydrin-based rubber, which are excellent in oil resistance, heat resistance, cold resistance and compression set characteristics. A sulfur rubber composition is provided.

[0002]

Acrylic rubber is known as an elastomer having oil resistance. Further, an ethylene-acrylic acid ester copolymer is known as an elastomer having an excellent balance of oil resistance, heat resistance and cold resistance. Further, a technique of improving oil resistance by blending an acrylic rubber with an ethylene-acrylic acid ester copolymer is also known (Japanese Patent Laid-Open No. 1-92251).
Publication). By the way, the required level for various properties such as oil resistance, heat resistance and cold resistance, and compression set have become more and more advanced in recent years, and in the above-mentioned conventional technology, it is difficult to satisfy the advanced required level. there were.

[0003]

SUMMARY OF THE INVENTION In view of the above situation, an object of the present invention is to provide a vulcanized rubber composition which is excellent in various properties such as oil resistance, heat resistance, cold resistance and compression set. To the point.

[0004]

The present inventors have arrived at the present invention as a result of intensive studies to solve the above problems. That is, in the present invention, one invention is 30 to 95 parts by weight of the following component (A) and 70 to 5 parts by weight of the component (B) (provided that the component (A) + the component (B) = 100 parts by weight). .) And the total amount of the components (A) and (B) 10
The present invention relates to a rubber composition containing 1 to 10 parts by weight of component (C) per 0 parts by weight. Component (A): Ethylene- (meth) acrylate ester-based copolymer rubber (B) Component: Epichlorohydrin-based rubber vulcanizable with organic peroxide (C) Component: Epoxy ring-containing compound

Another aspect of the present invention relates to a vulcanized rubber composition obtained by vulcanizing the above rubber composition with an organic peroxide.

The details will be described below. The component (A) of the present invention is an ethylene- (meth) acrylic acid ester-based copolymer rubber. The term "(meth) acrylic acid ester" as used herein means an acrylic acid ester and / or a methacrylic acid ester. As the (meth) acrylic acid ester, an ester composed of an alcohol having 1 to 8 carbon atoms is preferable, and specifically, methyl (meth) acrylate, (meth)
Acrylic acid-n-butyl, (meth) acrylic acid-ter
Examples thereof include t-butyl and 2-ethylhexyl (meth) acrylate, and these may be used alone or in combination of two or more.

The content ratio (molar ratio) of ethylene and (meth) acrylic acid ester is preferably 50:50 to 85:15, and more preferably 50:50 to 70:30.
Here, the amount of (meth) acrylic acid ester indicates the total amount of acrylic acid ester and methacrylic acid ester. When ethylene is excessive, the crystallinity of the copolymer becomes high and sufficient elasticity may not be obtained.
When the amount of acrylic ester is excessive, the embrittlement point of the copolymer becomes high, and it may be difficult to use the rubber as an elastic rubber at low temperature, which is not preferable.

As the ethylene- (meth) acrylic acid ester type copolymer rubber which is the component (A) of the present invention, in addition to the above-mentioned copolymer rubber composed of ethylene and (meth) acrylic acid ester, ethylene, ( A copolymer rubber containing a (meth) acrylic acid ester and an epoxy group-containing monomer is also included. The epoxy group-containing monomer acts as a cross-linking point during vulcanization, and for example, glycidyl acrylate, glycidyl methacrylate, itaconic acid diglycidyl ester, butene tricarboxylic acid triglycidyl ester, p-styrene carboxylic acid glycidyl ester, etc. And unsaturated glycidyl ethers such as vinyl glycidyl ether, allyl glycidyl ether, and methacryl glycidyl ether.

When the epoxy group-containing monomer is used, its content in the copolymer is preferably 8 mol% or less, more preferably 5 mol% or less. If the content is too large, the heat resistance and compression set may be poor. When an ethylene- (meth) acrylic acid ester-based copolymer rubber containing a carboxyl group-containing monomer is used as the component (A) without depending on the present invention, the compression set is inferior, which is inconvenient. is there.

The component (B) of the invention is an epichlorohydrin type rubber vulcanizable with an organic peroxide. Specifically, for example, epichlorohydrin-allyl glycidyl ether copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer, epichlorohydrin-propylene oxide-allyl glycidyl ether copolymer, epichlorohydrin-ethylene oxide-propylene oxide-allyl glycidyl ether. Examples thereof include copolymers.

The use ratio of the component (A) and the component (B) is
Component (A) 30 to 95 parts by weight, preferably 40 to 70 parts by weight, Component (B) 70 to 5 parts by weight, preferably 60 to 3 parts by weight.
0 parts by weight. When component (A) is too small, heat resistance and compression set are inferior, and when component (B) is too small, oil resistance is inferior.

The component (C) of the present invention is a compound containing an epoxy ring. In addition, ethylene as the component (A),
As described above, the copolymer rubber containing the (meth) acrylic acid ester and the epoxy group-containing monomer can be used. It means a compound other than a copolymer rubber containing an ester and an epoxy group-containing monomer.
Specific examples of the component (C) include an epoxy resin obtained by a condensation reaction of bisphenol A and epichlorohydrin, and an average molecular weight of 300 to 1500.
0, those having an epoxy equivalent of 100 to 10,000 are preferable. Here, the epoxy equivalent means the number of g of a resin containing 1 g equivalent of an epoxy group. The amount of component (C) used is
The total amount of the components (A) and (B) is 1 to 10 parts by weight, preferably 3 to 6 parts by weight, per 100 parts by weight. If the amount of component (C) is too small, reversion occurs and the mechanical properties are poor. On the other hand, when the component (C) is excessive, the heat resistance is poor.

The rubber composition of the present invention can be made into a vulcanized rubber composition by using an organic peroxide as a crosslinking agent. As the organic peroxide, an organic peroxide usually used for crosslinking rubber can be used, and examples thereof include di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, α, α-bis (t). -Butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane,
2,5-Dimethyl-2,5-di (t-butylperoxy) hexyne-3,1,1-bis (t-butylperoxy) -3.3.5-trimethylcyclohexane, n-butyl-4, 4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane,
2,2-bis (t-butylperoxy) octane and the like can be mentioned.

The amount of the organic peroxide used is preferably 1 to 10 parts by weight, more preferably 2 to 6 parts by weight, per 100 parts by weight of the total amount of the components (A) and (B). If the amount used is too small, the crosslink density is low, and the mechanical strength of the vulcanized rubber composition becomes insufficient. On the other hand, if the amount used is too large, problems such as foaming during vulcanization may occur.
Not preferable.

In the present invention, in order to improve the crosslinking efficiency during vulcanization with an organic peroxide, known crosslinking aids such as p, p'-dibenzoylquinonedioxime, quinonedioxime and triallyl cyanurate are used. , Sulfur, ethylene dimethacrylate, N, N′-m-phenylene bismaleimide, triallyl isocyanurate, trimethylolpropane trimethacrylate and the like may be used.

The method for obtaining the rubber composition and the vulcanized rubber composition of the present invention is, for example, as follows. In addition to the components (A) to (C) and the organic peroxide of the present invention, known antioxidants, vulcanization accelerators, processing aids, zinc white, stearic acid, reinforcing agents, and fillers may be added as necessary. A vulcanizable rubber composition is obtained by mixing a softening agent and the like using a conventional kneader such as a roll or Banbury. The rubber composition is molded into a shape suitable for the purpose, and undergoes a vulcanization step to obtain a vulcanized rubber composition which is the final molded product. Vulcanization is usually performed at a temperature of 120 ° C. or higher, preferably 150 to 220 ° C. for about 1 to 30 minutes.

The vulcanized rubber composition of the present invention is most suitable for fields utilizing its excellent characteristics, for example, various sealing materials (gaskets, O-rings, packings, oil seals), various hoses, belts, rolls, etc. Can be used for.

[0018]

EXAMPLES The present invention will be described with reference to Examples and Comparative Examples. Examples 1 to 7 and Comparative Examples 1 to 9 The rubber components and compounding agents shown in Tables 1 to 3 were kneaded with a 6 inch open roll at 50 to 60 ° C. for 15 to 20 minutes to give a vulcanizable rubber composition. Obtained. Next, the vulcanized rubber composition was press-vulcanized at 170 ° C. for 20 minutes to obtain a vulcanized rubber composition. Regarding the obtained vulcanized rubber composition, JIS-
Various physical properties were measured according to K-6301. The results are shown in Table 4.
~ 5. In addition, in Comparative Example 8, reversion occurred, and a vulcanized product which could be satisfied could not be obtained. Further, in Comparative Example 9, the vulcanization rate was too fast, and a vulcanized product that was satisfactory in terms of appearance and various physical properties could not be obtained.

The results show the following. The examples according to the present invention show satisfactory results in all evaluation items. On the other hand, Comparative Examples 1 and 2 not using the component (B)
Has poor oil resistance. Comparative Example 3 in which an acrylic acid ester copolymer not containing ethylene as a constituent component was used in place of the component (B) had a poor balance between oil resistance and cold resistance.
Comparative Examples 4 to 6 not using the component (A) are inferior in heat resistance and compression set. Comparative Example 7 using a copolymer containing a carboxyl group as a crosslinking point instead of the component (A) is inferior in compression set. Comparative Example 8 which did not use the component (C) caused reversion to vulcanization and could not be made into a satisfactory vulcanized product. A cross-linking system consisting of isocyanuric acid, octadecyl ammonium bromide, diphenylurea and Zisnet F (2,4,6-trimercapto-s-triazine, which is a cross-linking agent that is not an organic peroxide) is used without using an organic peroxide. In Comparative Example 9 in which vulcanization was attempted using the vulcanization rate, the vulcanization rate was too fast to obtain a vulcanized product that was satisfactory in terms of appearance and various physical properties.

[0020]

[Table 1] Formulation (parts by weight) --------------------------------------- Actual Example 1 2 3 4 5 6 7 Rubber component * 1 (A) Component type A1 A1 A1 A1 A1 A2 A1 amount 70 50 30 50 50 50 50 (B) Component type B1 B1 B1 B2 B3 B2 B1 amount 30 50 70 50 50 50 50 (C) component Epicort 828 * 2 5 5 5 5 5 5 5 FEF Black 40 40 40 40 40 40 40 Stearic acid 1 1 1 1 1 1 1 Armin 18D * 3 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Nocrac 224 * 4 1 1 1 1 1 1 1 -Antigen NBC * 5 1 1 1 1 1 1-Nowaug 445 * 6 1 1 1 1 1 1 2 DCPO * 7 5 5 5 5 5 5 4 Sumifine BM * 8 0.5 0.5 0.5 0.5 0.5 0.5 0.3 Isocyanuric acid--- ----ODTMAB * 9-------Diphenylurea-------Magnesium oxide-------NS-200 * 10-------Zisnet F * 11-- -----CML # 21 * 12------3 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

[0021]

[Table 2] Formulation (parts by weight) ----------------------------------------------- Comparative example 1 2 3 4 5 6 7 Rubber component * 1 (A) Component type A1 A2 A2----Amount 100 100 50----(B) Component type---B1 B2 B3 B3 amount---100 100 100 50 Other type-- X1---X2 Amount--50---50 (C) Ingredients Epicoat 828 * 2 5 5-5 5 5 5 FEF Black 40 40 40 40 40 40 40 Stearic acid 1 1 1 1 1 1 1 Armin 18D * 3 0.5 0.5 0.3 0.5 0.5 0.5 0.5 Nocrac 224 * 4 1 1-1 1 1 1 Antigen NBC * 5 1 1-1 1 1 1 Nowguard 445 * 6 1 1 2 1 1 1 1 DCPO * 7 5 5-5 5 5 5 Sumifine BM * 8 0.5 0.5-0.5 0.5 0.5 0.5 Isocyanuric acid--0.8----ODTMAB * 9--1.5----Diphenylurea--2.3----Magnesium oxide-------NS -200 * 10-------Zisnet F * 11-------−−−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−

[0022]

[Table 3] Composition (parts by weight)

[0023]

[Table 4] Evaluation results of vulcanized rubber composition ---------------------------------- Example 1 2 3 4 5 6 7 Tensile properties Tensile strength Kgf / cm ² 123 129 130 129 92 117 129 Elongation% 360 320 310 280 470 160 310 Hardness JIS-A 53 55 55 57 47 61 56 Oil resistance * 13 Volume swelling% 43 23 17 30 65 30 29 Cold resistance Embrittlement temperature ℃ -27 -24 -23 -30 -37 -27 -30 Heat resistance * 14 Rate of change of tensile strength -24 -44 -65 -41 -64 -15 -16 Change of elongation % 0 -9 -55 -7 -19 -25 -42 Hardness change Point +14 +8 +15 +4 +8 +8 +14 Compression set% * 15 40 45 55 42 46 48 31 −−−− −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

[0024]

[Table 5] Evaluation results of vulcanized rubber composition --------------------------------------------- Comparative Example 1 2 3 4 5 6 7 Tensile properties Tensile strength Kgf / cm ² 103 111 120 133 126 75 89 Elongation% 600 500 480 320 210 410 390 Hardness JIS-A 50 49 59 56 60 43 50 Oil resistance * 13 Volume swelling% 73 73 37 10 10 77 66 Cold resistance Embrittlement temperature ℃ -32 -32 -24 -21 -29 -44 -37 Heat resistance * 14 Rate of change in tensile strength +8 +42 +19 -88 -81 NM * 16 -19 Elongation Rate of change% -10 -66 -56 -34 -48 NM * 16 -69 Hardness change Point +22 +30 +13 -4 -3 NM * 16 +16 Compression set% * 15 47 76 29 73 56 50 90 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

* 1 Rubber component A1: ethylene (67 mol%)-methyl acrylate (33 mol
%) Copolymer rubber A2: ethylene (67 mol%)-methyl acrylate (32 mol
%)-Glycidyl methacrylate (1 mol%) copolymer rubber B1: ZEON Japan Zeklon 1100 (trade name) epichlorohydrin-allyl glycidyl ether copolymer rubber B2: Nippon ZEON Zeklon 3100 (trade name) epichlorohydrin-ethylene Oxide-allyl glycidyl ether copolymer rubber B3: ZEON Nippon Zeospan 303 (trade name) epichlorohydrin-propylene oxide-allyl glycidyl ether copolymer rubber X1: Nippon Zeon AR31 (trade name) ethyl acrylate-glycidyl methacrylate Copolymer X2: Du Pont Vamac G (trade name) ethylene-methyl acrylate-maleic acid monoethyl ester copolymer rubber

* 2 Epicoat 828, manufactured by Showa Shell Co., Ltd. Epoxy ring-containing compound (epoxy resin obtained by condensation reaction of bisphenol A and epichlorohydrin, molecular weight 380, epoxy equivalent 18
4 to 194) * 3 Armin 18D Lion Akzo's processing aid * 4 Nocrac 224 Ouchi Shinko's anti-aging agent * 5 Antigen NBC Sumitomo Chemical's anti-aging agent * 6 Noward 445 Uniroyal's anti-aging agent * 7 DCPO Dicumyl peroxide 40 wt% Sanken Kako Co., Ltd.
Organic peroxide

* 8 Sumifine BM Sumitomo Chemical Co., Ltd. Crosslinking aid * 9 ODTMAB Octadecyltrimethylammonium bromide * 10 NS-200 Nitto Koka Kogyo Co., Ltd. Antiaging agent (calcium bicarbonate) * 11 Zisnet F Nippon Zeon Cross-linking agent (2,4,6-trimercapto-s-triazine) * 12 CML # 21 Omi Chemical Co., Ltd. Antiaging agent (calcium oxide) * 13 Oil resistance JIS No.3 oil 150 ℃ x 70 hours * 14 Heat resistance 175 ℃ x 3 days Gear oven deterioration * 15 Compression set 150 ℃ x 70 hours * 16 NM Unmeasurable due to embrittlement due to heat deterioration

[0028]

As described above, according to the present invention, it is possible to provide a vulcanized rubber composition having excellent properties such as oil resistance, heat resistance, cold resistance and compression set.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noriyasu Yasuda 5-1 Anezaki Kaigan, Ichihara-shi, Chiba Sumitomo Chemical Co., Ltd.

Claims (2)

[Claims] 1. The following component (A) 30 to 95 parts by weight and component (B) 70 to 5 parts by weight (provided that component (A) +
Component (B) = 100 parts by weight. ) And (C) component per 100 parts by weight of the total amount of (A) component and (B) component
A rubber composition containing 10 to 10 parts by weight. Component (A): Ethylene- (meth) acrylate ester-based copolymer rubber (B) Component: Epichlorohydrin-based rubber vulcanizable with organic peroxide (C) Component: Epoxy ring-containing compound 2. A vulcanized rubber composition obtained by vulcanizing the rubber composition according to claim 1 with an organic peroxide.