Process for the preparation of a silicone pressure-sensitive adhesive

A method of obtaining a silicone pressure-sensitive adhesive composition comprising the sequential steps of:

• (I) forming a polymer mixture comprising:
• (A) forming a silicone polymer by condensation polymerization of at least one polyorganosiloxane in the presence of at least one hydrocarbon solvent or silicone fluid,
• wherein the at least one polyorganosiloxane has an average solution viscosity of from about 1 mm2/s to about 200 mm2/s at 25° C. and at least one hydroxyl group capable of undergoing condensation polymerization,
• wherein polymerization is facilitated by addition of at least one condensation catalyst and occurs at a temperature of from about 30° C. to about 110° C., wherein the silicone polymer formed has a solution viscosity of from about 10,000 mm2/s to about 5,000,000 mm2/s at 25° C. and has a molecular weight greater than 1,000,000 g/mol and wherein the polymer mixture includes the silicone polymer;
• (B) optionally, including a silicone resin that has at least one hydroxyl group capable of undergoing condensation polymerization and that is soluble in at least one hydrocarbon solvent or silicone fluid,
• wherein the resin has a hydroxyl group content of from about 0.5% to about 2.5% (by weight based on resin solids content),
• wherein the resin comprises R3SiO1/2 units and SiO4/2 units in a molar ratio of from about 0.6 to about 1.5 (R3SiO1/2 units:
• SiO4/2 units),
• wherein R is independently selected from a monovalent hydrocarbon or a halohydrocarbon radical having from 1 to 20 carbon atoms, an alkenyl radical, or a hydroxyl radical and wherein the polymer mixture optionally includes the silicone resin;
• and
• (C) optionally, including a neutralizing agent, wherein the neutralizing agent is added in an amount sufficient to neutralize the condensation catalyst and wherein the polymer mixture optionally includes the neutralizing agent;
• (II) mixing with the polymer mixture of (I), at least one bodying catalyst and a silicone resin that has at least one hydroxyl group capable of undergoing bodying;
• and then allowing a bodying reaction to occur at a temperature of from about 40° C. to about 145° C. to form the silicone pressure-sensitive adhesive composition,
• wherein the resin is soluble in at least one hydrocarbon solvent or silicone fluid,
• wherein the resin has a hydroxyl group content of from about 0.5% to about 2.5% (by weight based on resin solids content),
• wherein the silicone resin comprises R3SiO1/2 units and SiO4/2 units in a molar ratio of from about 0.6 to about 1.5 (R3SiO1/2 units:
• SiO4/2 units), and
• wherein R is independently selected from a monovalent hydrocarbon or a halohydrocarbon radical having from 1 to 20 carbon atoms, an alkenyl radical, or a hydroxyl radical;
• and
• (III) optionally, adding to the silicone pressure-sensitive adhesive composition of (II) from about 0.5% to about 3.5% (by weight) of an organic peroxide.