Claims
- 1. A polyolefin rubber composition for a polyolefin rubber which has superior electrical insulation and considerably-improved heat resistance, consisting essentially of:
- (a) 100 part by weight (pbw) ethylenic copolymer;
- said ethylenic copolymer being a copolymer consisting essentially of from 40 to 90 mol percent ethylene, from 10 to 60 mol percent alpha-olefin monomer other than ethylene, and from 3 to 20 mol percent conjugate or non-conjugate diolefine monomer;
- (b) from 18-58 pbw monoethylenically unsaturated monomer to improve the heat-resistance of said polyolefin rubber;
- said monoethylenically unsaturated monomer selected from the group consisting of styrene and methylmethacrylate;
- (c) from 2-12 pbw polyethylenically unsaturated monomer for vulcanizing said ethylenic copolymer to improve the heat-resistance of said polyolefin rubber;
- said polyethylenically unsaturated monomer selected from the group consisting of divinyl benzene and trimethylolpropane trimethacrylate;
- wherein the ratio of the weight of said polyethylenically unsaturated monomer to that of said monoethylenically unsaturated monomer is about 0.03-0.25,
- wherein said polyethylenically unsaturated monomer is divinyl benzene when styrene is used as the monoethylenically unsaturated monomer, and trimethylolpropane trimethacrylate when methylmethacrylate is used as the monethylenically unsaturated monomer; and
- (d) from 0.1 to 15 pbw organic peroxide for initiation of the vulcanization.
- 2. The polyolefin rubber made from the composition of claim 1, having the following improved electrical characteristics especially useful in connection with an automobile engine:
- withstands voltage: at least 26 KV/mm
- dielectric constant: 2.5
- dielectric dissipation factor: 4 x 10.sup.- 3.
- 3. The polyolefin composition according to claim 1, wherein said organic peroxide is taken from the group consisting of dicumyl peroxide, 2,5-dimethyl-2,5-ditertiary butylperoxyhexane and 1-1-bis tertiary butyl peroxy 3,3,5-trimethylcyclohexane.
- 4. The composition according to claim 1, wherein said organic peroxide is dicumyl peroxide.
- 5. The composition according to claim 4, wherein said dicumyl peroxide is present in 2.7 pbw.
Priority Claims (1)
Number |
Date |
Country |
Kind |
60-99490 |
May 1985 |
JPX |
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Parent Case Info
This is a continuation of co-pending application Ser. No. 861,409 filed on May 9, 1986, now abandoned.
US Referenced Citations (4)
Foreign Referenced Citations (1)
Number |
Date |
Country |
49-128953 |
Oct 1974 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
861409 |
Jun 1986 |
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