Low viscosity silicone foam compositions

Claim 1

A foamable composition comprising: (a) 100 parts by weight vinyl-containing polysiloxane comprising: (i) vinyl endcapped polysiloxane composition having a viscosity between about 10,000 and 1,000,000 centipoise at 25° C. and containing vinyl endcapped polysiloxane having the formula: ##STR4## where R is vinyl and R 1 is selected from substituted or unsubstituted hydrocarbon radicals of from 1 to 20 carbon atoms, such that the polymer contains from 0.0002 to 3% by weight vinyl and x varies such that the viscosity of said vinyl endcapped polysiloxane varies from 100 to 1,000,000 centipoise at 25° C., and (ii) in an amount of from 1/9 to 9/1 by weight to said vinyl endcapped polysiloxane composition a low viscosity vinyl containing polysiloxane composition comprising low viscosity vinyl-containing polysiloxane having the formula: ##STR5## where R 4 and R 5 are selected from substituted or unsubstituted hydrocarbon radicals of from 1 to 20 carbon atoms, at most, one R 4 is vinyl, the polymer contains 0.0002 to 1% by weight vinyl, and w varies such that the viscosity of said low viscosity vinyl containing polysiloxane varies from 50 to about 2,000 centipoise at 25° C.; (b) from 1 to 50 parts by weight of a hydride polysiloxane of the formula: ##STR6## where R 2 is selected from the group consisting of independently, hydrogen, alkyl radicals of from 1 to 8 carbon atoms, aryl radicals of from 1 to 8 carbon atoms, haloalkyl radicals of 3 to 8 carbon atoms and simultaneously, a single --O-- to form a cyclic polymer and R 3 is selected from the group consisting of alkyl radicals of from 1 to 8 carbon atoms, aryl radicals of from 1 to 8 carbon atoms, and fluoroalkyl radicals of 3 to 8 carbon atoms, where the hydride polysiloxane has a hydrogen content varying from 0.3 to 1.6% by weight and z and y vary such that the polymer has a viscosity varying from 1 to 500 centipoise at 25° C.; (c) a hydroxyl source selected from the group consisting of water, organic alcohol, hydroxylated siloxane, and combinations thereof in an amount to provide a molar ratio of from about 0.02/1 to about 5/1 of hydroxyl radicals to silicon-bonded hydrogen atoms of component (b); and (d) from about 1 to about 250 parts per million of platinum catalyst.