Peroxide-curable fluorosilicone copolymer compositions
First Claim
1. A peroxide-curable silanol-endstopped or alkenyl-endstopped diorganopolysiloxane copolymer having a molecular weight of from about 400,000 to about 600,000 comprising units of the formulae RR'"'"'SiO and R"2 SiO, wherein R is fluoroalkyl of from 3 to 8 carbon atoms, R'"'"' is alkyl of from 1 to 8 carbon atoms, alkenyl of from 2 to 8 carbon atoms, or phenyl, and wherein sufficient RR'"'"'SiO units are present to provide about 45-65 mole percent fluorosilicone content and sufficient R"2 SiO units containing alkenyl substituents are present to provide a vinyl content along the polysiloxane chain of about 0.02 weight percent to about 0.5 weight percent as CH2 ═
- CH--.
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Abstract
Peroxide-curable fluorosilicone copolymers are provided which, when compounded and cured, form elastomers of superior physical properties, especially in terms of solvent swell and thermal aging. Curable compositions prepared according to the present invention make possible the efficient production of high quality electrical connectors for aerospace and other applications.
26 Citations
19 Claims
- 1. A peroxide-curable silanol-endstopped or alkenyl-endstopped diorganopolysiloxane copolymer having a molecular weight of from about 400,000 to about 600,000 comprising units of the formulae RR'"'"'SiO and R"2 SiO, wherein R is fluoroalkyl of from 3 to 8 carbon atoms, R'"'"' is alkyl of from 1 to 8 carbon atoms, alkenyl of from 2 to 8 carbon atoms, or phenyl, and wherein sufficient RR'"'"'SiO units are present to provide about 45-65 mole percent fluorosilicone content and sufficient R"2 SiO units containing alkenyl substituents are present to provide a vinyl content along the polysiloxane chain of about 0.02 weight percent to about 0.5 weight percent as CH2 ═
-
4. A curable fluorosilicone composition comprising (A) a silanol-endstopped or alkenyl-endstopped diorganopolysiloxane copolymer having a molecular weight of from about 400,000 to about 600,000 comprising units of the formulae RR'"'"'SiO and R"2 SiO, wherein R is fluoroalkyl of from 3 to 8 carbon atoms, R'"'"' is alkyl of from 1 to 8 carbon atoms or phenyl, and each R" is, independently, alkyl of from 1 to 8 carbon atoms, alkenyl of from 2 to 8 carbon atoms, or phenyl, and wherein sufficient RR'"'"'SiO units are present to provide about 45-65 mole percent fluorosilicone content and sufficient R"2 SiO units containing alkenyl substituents are present to provide a vinyl content along the polysiloxane chain of from about 0.02 weight percent to about 0.5 weight percent as CH2 ═
- CH--; and
(B) a peroxide curing catalyst. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13)
- CH--; and
-
14. A curable fluorosilicone composition comprising (A) a silanol-endstopped or vinyl-endstopped diorganopolysiloxane copolymer having a molecular weight of from 400,000 to about 600,000 comprising units of the formulae RR'"'"'SiO and R"2 SiO, wherein R is fluoroalkyl of from 3 to 8 carbon atoms, R'"'"' is alkyl of from 1 to 8 carbon atoms, and each R" is, independently, alkyl of from 1 to 8 carbon atoms or vinyl, and wherein sufficient R-containing units are present to provide about 50-60 mole percent fluorosilicone content and sufficient vinyl-functional units are present to provide a vinyl content along the polysiloxane chain of about 0.02-0.5 weight percent as CH2 ═
- CH--;
(B) a peroxide curing catalyst in which at least one peroxide oxygen is attached to a tertiary carbon atom; and
(C) cerium hydroxide. - View Dependent Claims (15, 16, 17, 18, 19)
- CH--;
Specification