Reinforced silicone resin film and method of preparing same

A method of preparing a reinforced silicone resin film, the method comprising the steps of:nimpregnating a fiber reinforcement in a condensation-curable silicone composition comprising a silicone resin; andcuring the silicone resin of the impregnated fiber reinforcement; wherein the reinforced silicone resin film comprises from 10 to 99% (w/w) of the cured silicone resin, and the film can be bent over a cylindrical steel mandrel having a diameter less than or equal to 3.2 mm in accordance with ASTM Standard D522-93a Method B without cracking;wherein the condensation-curable silicone composition comprises a silicone resin having the formula (R1R22SiO1/2)w(R22SiO2/2)x(R2SiO3/2)y(SiO4/2)z (I), wherein R1 is independently C1 to C10 hydrocarbyl or C1 to C10 halogen-substituted hydrocarbyl, R2 is independently R1, —H, —OH, or a hydrolysable group, w is from 0 to 0.8, x is from 0 to 0.6, y is from 0 to 0.99, z is from 0 to 0.35, w+x+y+z=1, y+z/(w+x+y+z) is from 0.2 to 0.99, and w+x/(w+x+y+z) is from 0 to 0.8, provided when y is 0, w+x/(w+x+y+z) is from 0.05 to 0.8, and the silicone resin has an average of at least two silicon-bonded hydrogen atoms, hydroxyl groups, or hydrolysable groups per molecule.

A method of preparing a reinforced silicone resin film, the method comprising the steps of:nimpregnating a fiber reinforcement in a condensation-curable silicone composition comprising a silicone resin; andcuring the silicone resin of the impregnated fiber reinforcement; wherein the reinforced silicone resin film comprises from 10 to 99% (w/w) of the cured silicone resin, and the film can be bent over a cylindrical steel mandrel having a diameter less than or equal to 3.2 mm in accordance with ASTM Standard D522-93a Method B without cracking;wherein the condensation-curable silicone composition comprises (A) a rubber-modified silicone resin prepared by reacting an organosilicon compound selected from (i) a silicone resin having the formula (R1R42SiO1/2)w(R42SiO2/2)x(R4SiO3/2)y(SiO4/2)z (II) and (ii) hydrolysable precursors of (i), and a silicone rubber having the formula R53SiO(R1R5SiO)mSiR53 (III) in the presence of water, a condensation catalyst, and an organic solvent to form a soluble reaction product, wherein R1 is independently C1 to C10 hydrocarbyl or C1 to C10 halogen-substituted hydrocarbyl, R4 independently is R1, —OH, or a hydrolysable group, R5 independently is R1 or a hydrolysable group, m is from 2 to 1,000, w is from 0 to 0.8, x is from 0 to 0.6, y is from 0 to 0.99, z is from 0 to 0.35, w+x+y+z=1, y+z/(w+x+y+z) is from 0.2 to 0.99, and w+x/(w+x+y+z) is from 0 to 0.8, provided when y is 0, w+x/(w+x+y+z) is from 0.05 to 0.8, the silicone resin (II) has an average of at least two silicon-bonded hydroxy or hydrolysable groups per molecule, the silicone rubber (III) has an average of at least two silicon bonded hydrolysable groups per molecule, and the mole ratio of silicon-bonded hydrolysable groups in the silicone rubber (III) to silicon-bonded hydroxy or hydrolysable groups in the silicone resin (II) is from 0.01 to 1.5; and (B) a condensation catalyst.