Patent ID: 7479532

Claim:
A method for preparing a fluorocarbon elastomeric base composition comprising: (I) mixing (A) a silicone base comprising (A′) a diorganopolysiloxane containing at least 2 alkenyl groups having 2 to 20 carbon atoms, and (A″) an optional reinforcing filler, (B) an optional crosslinking agent, (C) a free radical initiator cure agent, to form a silicone compound; (II) mixing the silicone compound with (D) a fluorocarbon elastomer having a glass transition temperature (T g ) below 15° C., (E) compatibilizer selected from; (E 1 ) an organic compounds which contain 2 or more olefin groups, (E 2 ) organopolysiloxanes containing at least 2 alkenyl groups, (E 3 ) olefin-functional silanes which also contain at least one hydrolyzable group or at least one hydroxyl group attached to a silicon atom thereof, (E 4 ) an organopolysiloxane having at least one organofunctional groups selected from amine, amide, isocyanurate, phenol, acrylate, epoxy, and thiol groups, (E 5 ) a dehydrofluorination agent, and any combinations of (E 1 ), (E 2 ), (E 3 ), (E 4 ) and (E 5 ), (F) an organic peroxide catalyst; and (III) dynamically vulcanizing the silicone compound, wherein the weight ratio of fluorocarbon elastomer (D) to silicone base (A) in the etastomeric base composition ranges from 95:5 to 30:70.