Modified silicon elastomers having improved flex life and method therefor
AssigneeGeneral Electric Company
InventorsRosalyn J. Rufer, Walter H. Filbert
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Abstract
A silicone elastomer having improved flex life and a method of improving the flex life of silicone elastomers having olefinic unsaturation is described. The flex life of silicone elastomers having olefinic unsaturation is improved substantially by mixing vinyl acetate ethylene copolymer with the silicone elastomer in the presence of a free radical catalyst at an elevated temperature. In a preferred embodiment, methyl vinyl silicone rubber is mixed with vinyl acetate copolymer in the presence of dicumyl peroxide at an elevated temperature to provide a silicone elastomer having improved flex life.
Claims24
A method of improving the flex life of silicone elastomers having olefinic unsaturation, comprising:
- I. mixing
- (a) from about 2% to about 10% by weight vinylacetate ethylene copolymer based on the weight of (b), and
- (b) a silicone elastomer having olefinic unsaturation in the presence of
- (c) a free radical catalyst;
- II. heating the mixture of step I at an elevated temperature to cure or crosslink the mixture and
- III. cooling the mixture.
A method of improving the flex life of silicone elastomers having olefinic unsaturation comprising:
- (a) milling vinyl acetate ethylene copolymer for a sufficient time to provide a softened gum;
- (b) adding a silicone elastomer having olefinic unsaturation such that the amount of vinyl acetate ethylene copolymer is about 2.0% to about 10.0% by weight of the silicone elastomer having olefinic unsaturation;
- (c) adding a sufficient amount of a free radical catalyst to crosslink the silicone elastomer having olefinic unsaturation and the vinyl acetate ethylene copolymer;
- (d) milling the mixture of free radical catalyst, vinyl acetate ethylene copolymer and silicone elastomer having olefinic unsaturation until the vinyl acetate ethylene copolymer is uniformly dispersed in the silicone elastomer;
- (e) heating the mixture of free radical catalyst, vinyl acetate ethylene copolymer and silicone elastomer having olefinic unsaturation at a temperature sufficient to cure the silicone elastomer;
- and
- (f) cooling the cured silicone elastomer.
A method of improving the flex life of silicone elastomers having olefinic unsaturation comprising:
- (a) milling silicone elastomer having olefinic unsaturation for a sufficient time to provide a softened gum;
- (b) adding vinyl acetate ethylene copolymer such that the amount of vinyl acetate ethylene copolymer is about 2.0% to about 10.0% by weight of the silicone elastomer having olefinic unsaturation;
- (c) adding a sufficient amount of a free radical catalyst to crosslink the silicone elastomer having olefinic unsaturation and the vinyl acetate ethylene copolymer;
- (d) milling the mixture of free radical catalyst, vinyl acetate ethylene copolymer and silicone elastomer having olefinic unsaturation until the vinyl acetate ethylene copolymer is uniformly dispersed in the silicone elastomer;
- (e) heating the mixture of free radical catalyst, vinyl acetate ethylene copolymer and silicone elastomer having olefinic unsaturation at a temperature sufficient to cure the silicone elastomer;
- and
- (f) cooling the cured silicone elastomer.
A silicone elastomer having improved flex life comprising a silicone elastomer having olefinic unsaturation and about 2.0% to about 10.0% by weight vinyl acetate ethylene copolymer crosslinked in the presence of a free radical catalyst.
Dependencies are inferred from the claim text.