Silicone rubber composition and method for curing the same
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsMasaharu Takahashi, Jun Hatakeyama
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Abstract
The invention provides a silicone rubber composition which is efficiently curable by exposure to microwaves but, different from conventional microwave-curable silicone rubber compositions compounded with a deep-colored energy-absorbing agent, is still capable of being colored in any desired color because the energy-absorbing agent compounded therein is not colored. The energy-absorbing agent used here is a silica or polyorganosilsesquioxane powder having cyanoalkyl or fluoroalkyl groups bonded to the silicon atoms.
Claims21
A silicone rubber composition curable by irradiation with high-frequency electromagnetic waves which comprise, as a uniform blend:
- (a) 100 parts by weight of a diorganopolysiloxane represented by the average unit formula
- R.sub.a SiO.sub.(4-a)/2,
- in which R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms and a is a positive number in the range from 1.95 to 2.05, and having an average degree of polymerization in the range from 3,000 to 30,000;
- (b) from 10 to 300 parts by weight of an unmodified finely divided silica filler substantially having a chemical formula of SiO.sub.2 ;
- (c) from 25 to 100 parts by weight of an organic-modified silica or polyorganosilsesquioxane powder each having cyanoalkyl functional organic groups bonded to the silicon atoms, the content of the functional organic groups being at least 0.3% by weight in the silica or polyorganosilsesquioxane powder;
- and
- (d) an organic peroxide curing agent in an amount sufficient to cure the composition when the composition is heated.
A method for the preparation of a cured silicone rubber article which comprises:
- (A) compounding into a uniform composition,
- (a) 100 parts by weight of a diorganopolysiloxane represented by the average unit formula
- R.sub.a SiO.sub.(4-a)/2,
- in which R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms and a is a positive number in the range from 1.95 to 2.05, and having an average degree of polymerization in the range from 3,000 to 30,000;
- (b) from 10 to 300 parts by weight of a finely divided silica filler substantially having a chemical formula of SiO.sub.2 ;
- (c) from 10 to 200 parts by weight of an organic-modified silica or polyorganosilsesquioxane powder having cyanoalkyl functional organic groups bonded to the silicon atoms, the content of the functional organic groups being at least 0.3% by weight in the silica or polyorganosilsesquioxane powder;
- and
- (d) an organic peroxide curing agent in an amount sufficient to cure the composition when the composition is heated;
- (B) shaping the composition into a form;
- and
- (C) exposing the shaped form to ultrahigh frequency electromagnetic waves having a frequency in the range from 900 MHz to 5000 MHz.
Dependencies are inferred from the claim text.