Fluorinated aliphatic acids as processing aids for silicone rubber compositions

Claim 2

The silicone rubber composition of claim 2 wherein R is selected from the class consisting of methyl and phenyl and wherein at least 50 percent of the R radicals are methyl.

Claim 3

The silicone rubber composition of claim 3 wherein the silicone structure-controlling additive is a hydroxylated organosilane having a silicon-bonded OH content of from one OH per 70 silicon atoms to 2 OH per silicon atom and having from 1.9 to 2.1 hydrocarbon radicals per silicon atom, said radicals being selected from the group consisting of alkyl radicals, radicals of less than six carbon atoms and monocyclic aryl hydrocarbon radicals with any remaining valences of the silicon atoms in the hydroxylated silane being satisfied by oxygen atoms.

Claim 4

The silicone rubber composition of claim 3 wherein the silicone structure-controlling additive is a dihydrocarbon-substituted polysiloxane oil having a hydrocarbon substituent to silicon atom ratio of from 1.6 to 2.0 and where said hydrocarbon substituents comprise at least one member selected from the class consisting of methyl, ethyl, vinyl, allyl, cyclohexenyl and phenyl groups, said polysiloxane oil comprising polysiloxane molecules containing an average of from one to two lower alkoxy groups bonded to each of the terminal silicon atoms.

Claim 5

The composition of claim 4 further including 0.1 to 10 percent by weight of a peroxide curing agent based on the weight of said polydiorganosiloxane and selected from the group consisting of benzoyl peroxide, di-tertiary-butyl peroxide, tertiary-butyl-triethylmethyl peroxide, tertiary-butyl-tertiary-triptyl peroxide and dicumyl peroxide, and 2,4-dichlorobenzoyl peroxide.

Claim 6

A process for forming a heat-curable silicone rubber composition comprising mixing a polydiorganosiloxane convertible to the solid, cured, elastic state and having the formula, with 1 to 25 percent by weight based on the weight of said polydiorganosiloxane of a silicone structure-controlling additive and 100 to 1,000 ppm of a fluorine-substituted hydrocarbon based on the weight of said polydiorganosiloxane and selected from the class consisting of compounds of the formula, and compounds of the formula, and then adding to said mixture a structure-defining inorganic filler where R and R'' are radicals selected from the class consisting of alkyl radicals, aryl radicals, aralkyl radicals, alkenyl radicals, cycloalkyl radicals, and cycloalkenyl radicals, n has a value that varies from 1.98 to 2.01, inclusive, X is a radical selected from the class consisting of chlorine, fluorine, and the same radicals as R'', R2 is selected from the class consisting of hydrogen, fluorine and the same radicals as R'', R3 is selected from the class consisting of alkylene and arylene radicals, and n is a whole number that varies from 0 to 1, inclusive.

Claim 7

The process of claim 7 wherein the fluorine-substituted hydrocarbon acid is trifluoroacetic acid.

Claim 8

The process of claim 7 wherein there is added 10-200 percent of said inorganic filler based on the weight of said polydiorganosiloxane.

Claim 9

The process of claim 7 wherein the final mixture containing the organic filler is heated to 150*-200* C for 2-12 hours.

Claim 10

The process of claim 10 wherein after the heating step there is added to the reSulting mixture 0.1 to 10 percent by weight of a peroxide curing agent based on the weight of the polydiorganosiloxane and selected from the group consisting of benzoyl peroxide, di-tertiary-butyl peroxide, tertiary-butyl-triethylmethyl peroxide, tertiary-butyl-tertiary-triptyl peroxide, dicumyl peroxide and 2,4-dichloro-benzoyl peroxide.

Claim 11

The process of claim 8 wherein R is selected from the class consisting of methyl and phenyl and wherein at least 50 percent of the R radicals are methyl.

Claim 12

The process of claim 8 wherein the silicone structure -controlling additive is a hydroxylated organosilane having a silicon-bonded OH content of from one OH per 70 silicon atoms to two OH per silicon atom and having from 1.9 to 2.1 hydrocarbon radicals per silicon atom, said radicals being selected from the group consisting of alkyl radicals of less than six carbon atoms and monocyclic aryl hydrocarbon radicals with any remaining valences of the silicon atom in the hydroxylated silane being satisfied by oxygen atoms.

Claim 13

The process of claim 8 wherein the silicone structure-controlling additive is a dihydrocarbon-substituted polysiloxane oil having a hydrocarbon substituent to silicon atom ratio of from 1.0 to 2.0 and where said hydrocarbon substituents comprise at least one member selected from the class consisting of methyl, ethyl, vinyl, allyl, cyclohexenyl and phenyl groups, said polysiloxane oil comprising polysiloxane molecules containing an average of from one to two lower alkoxy groups bonded to each of the terminal silicon groups.