Polysiloxane emulsion elastomers reinforced with emulsified organo-silicone copolymers

Claim 1

A method of blending aqueous emulsions to provide an elastomeric product upon devolatization comprising: (I) mixing (A) an aqueous emulsion of an anionic emulsion polymerized hydroxyl endblocked polydiorganosiloxane, said hydroxyl endblocked polydiorganosiloxane having a weight average molecular weight of at least 5000, the organo groups being selected from the group consisting of monovalent hydrocarbon radicals containing less than seven carbon atoms per radical and 2-(perfluoroalkyl)ethyl radicals containing less than seven carbon atoms per radical, and (B) an aqueous emulsion of an emulsion polymerized copolymer consisting essentially of free radical polymerized monomers selected from at least one unsaturated organic monomer and at least one unsaturated organosilicon monomer selected from the group consisting any unsaturated silane, siloxane, or silazane that will both copolymerize with the unsaturated organic monomer or mixture of unsaturated organic monomers used and will form .tbd.SiOH under the conditions of the emulsion polymerization method used to produce the copolymer, said copolymer being produced from 1 to 7 weight percent unsaturated organosilicon monomer and 93 to 99 weight percent unsaturated organic monomer, to form a mixture of emulsions, (II) adjusting the mixture to a pH of 7 or greater, (III) adding with agitation an amount of aqueous emulsion, (C), of an alkyl tin salt to provide from 0.1 to 2 parts by weight of alkyl tin salt for each 100 parts by weight of polydiorganosiloxane, and thereafter (IV) adding with agitation an amount of silane cross-linking agent, (D), to obtain crosslinking, said silane crosslinking agent having the general formula A m Si(OR) 4-m wherein A is a member selected from the group consisting of a hydrogen atom, monovalent hydrocarbon radicals containing 1 to 6 inclusive carbon atoms and monovalent halohydrocarbon radicals containing 1 to 6 inclusive carbon atoms, R is a member selected from the group consisting of a hydrogen atom, an alkyl group containing 1 to 4 inclusive carbon atoms, ##STR3## --CH 2 CH 2 OH, --CH 2 CH 2 OCH 3 , and --CH 2 CH 2 OC 2 H 5 group and m is 0 or 1, there being for each 100 parts by weight of polydiorganosiloxane in (A) sufficient (B) to provide from 5 to 60 parts by weight of emulsion polymerized copolymer.

Claim 2

A method of blending aqueous emulsions to provide an elastomeric product upon devolatization comprising: (I) mixing (A) an aqueous emulsion of an anionic emulsion polymerized hydroxyl endblocked polydiorganosiloxane, said hydroxyl endblocked polydiorganosiloxane having a weight average molecular weight of at least 5000, the organo groups being selected from the group consisting of monovalent hydrocarbon radicals containing less than seven carbon atoms per radical and 2-(perfluoroalkyl)ethyl radicals containing less than seven carbon atoms per radical, and (B) an aqueous emulsion of an emulsion polymerized copolymer consisting essentially of free radical polymerized monomers selected from at least one unsaturated organic monomer and at least one unsaturated organosilicon monomer selected from the group consisting any unsaturated silane, siloxane, or silazane that will both copolymerize with the unsaturated organic monomer or mixture of unsaturated organic monomers used and will form .tbd.SiOH under the conditions of the emulsion polymerization method used to produce the copolymer, said copolymer being produced from 1 to 7 weight percent unsaturated organosilicon monomer and 93 to 99 weight percent unsaturated organic monomer, to form a mixture of emulsions, (II) adjusting the mixture to a pH of 7 or greater, (III) adding with agitation an amount of aqueous emulsion, (C), of an alkyl tin salt to provide from 0.1 to 2 parts by weight of alkyl tin salt for each 100 parts by weight of polydiorganosiloxane, and thereafter (IV) adding with agitation an amount of silane cross-linking agent, (D), to obtain crosslinking, said silane crosslinking agent having the general formula A m Si(OR) 4-m wherein A is a member selected from the group consisting of a hydrogen atom, monovalent hydrocarbon radicals containing 1 to 6 inclusive carbon atoms and monovalent halohydrocarbon radicals containing 1 to 6 inclusive carbon atoms, R is a member selected from the group consisting of a hydrogen atom, an alkyl group containing 1 to 4 inclusive carbon atoms, ##STR3## --CH 2 CH 2 OH, --CH 2 CH 2 OCH 3 , and --CH 2 CH 2 OC 2 H 5 group and m is 0 or 1, there being for each 100 parts by weight of polydiorganosiloxane in (A) sufficient (B) to provide from 5 to 60 parts by weight of emulsion polymerized copolymer.