Dow Corning Corporation

Edward Joseph Benson

Ann Walstrom Norris

Joseph Norbert Clark

Stanton James Dent

Peter Lamont

Joseph T Braun

Yeong Joo Lee

A vacuum dispensable silicone composition comprising (A) a polydiorganosiloxane containing an average of at least two silicon-bonded alkenyl groups per molecule; (B) an organopolysiloxane resin consisting essentially of (a) R.sup.3.sub.2 (CH.sub.2 .dbd.CH)SiO.sub.1/2 siloxane units, (b) R.sup.3.sub.3 SiO.sub.1/2 siloxane units, and (c) SiO.sub.4/2 siloxane units wherein each R.sup.3 is independently selected from the group consisting of monovalent hydrocarbon and monovalent halogenated hydrocarbon groups free of aliphatic unsaturation, the mole ratio of the combination of (a) and (b) units to (c) units is from 0.6 to 1.1, and the resin contains 1 to 5 percent by weight of vinyl groups; (C) an organohydrogenpolysiloxane having an average of at least three silicon-bonded hydrogen atoms per molecule in an amount sufficient to provide from one to three silicon-bonded hydrogen atoms per alkenyl group in components (A) and (B) combined; (D) an adhesion promoter in an amount sufficient to effect adhesion of the composition to a substrate; (E) a hydrosilylation catalyst; (F) a platinum catalyst inhibitor having a boiling point greater than 150 .degree. C. at 0.10 MPa in an amount sufficient to retard curing of the composition at ambient temperature; wherein the composition is substantially free of air.

Vacuum dispensable silicone compositions

The instant invention pertains to a method of producing silicone pressure sensitive adhesives wherein the method comprises (I) combining together (A) a benzene soluble, hydroxyl containing organopolysiloxane resin consisting essentially of R.sub.3 SiO.sub.1/2 siloxane units and SiO.sub.4/2 siloxane units, wherein R is a monovalent radical selected from the group consisting of hydrocarbon and halogenated hydrocarbon radicals having from 1 to 10 carbon atoms; there being from 0.5 to 1.5 R.sub.3 SiO.sub.1/2 units for every SiO.sub.4/2 units and there being 1.0 to 4 wt %, based on FTIR, hydroxyl functionality and (B) a hydroxyl containing polydiorganosiloxane having a viscosity of .gtoreq.100 mPa's and (C) a catalyst selected from the group consisting of a weak organic acid or metal salt thereof; and thereafter (II) heating the mixture of (A), (B) and (C) for a time sufficient to produce the silicone pressure sensitive adhesive.

Method of making silicone pressure sensitive adhesives

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Midland, MI, United States of America

Edward Joseph Benson