Foamable siloxane compositions and silicone foams prepared therefrom
AssigneeDow Corning Corporation
InventorsBrian Paul Loiselle, Lawrence Joseph Rapson
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Abstract
Foamable organosiloxane compositions which yield, upon cure, silicone foams having low density and decrease friability, comprising (A) a siloxane base polymer system which is a combination of a high molecular weight hydroxyl-group containing siloxane polymer and a low molecular weight hydroxyl-group containing siloxane polymer; (B) a silicon-containing crosslinker for the siloxane base polymer system, wherein the crosslinker contains at least two --SiH groups per molecule; (C) a platinum group catalyst; and optionally (E) a blowing agent; and silicone foams prepared therefrom. A method of weather-stripping a door or window using the silicone foam so prepared.
Claims20
A foamable organosiloxane composition, comprising:
- (A) a siloxane base polymer system comprising:
- (i) a high molecular weight polyorganosiloxane containing an average of at least two hydroxyl groups per molecule and having a viscosity at 25.degree. C. (V.sub.i);
- and
- (ii) a low molecular weight polyorganosiloxane containing an average of at least two hydroxyl groups per molecule and having a viscosity at 25.degree. C. (V.sub.ii);
- wherein V.sub.ii .ltoreq.V.sub.i -25,000 mPa.s;
- (B) a silicon-containing crosslinker for the siloxane base polymer system, wherein the crosslinker contains at least two --SiH groups per molecule;
- and
- (C) a platinum group catalyst sufficient for curing the foamable organosiloxane composition.
The foamed product obtained from the incipient materials:
- (A) a siloxane base polymer system comprising:
- (i) a high molecular weight polyorganosiloxane containing an average of at least two hydroxyl groups per molecule and having a viscosity at 25.degree. C. (V.sub.i);
- and
- (ii) a low molecular weight polyorganosiloxane containing an average of at least two hydroxyl groups per molecule and having a viscosity at 25.degree. C. (V.sub.ii);
- wherein V.sub.ii .ltoreq.V.sub.i -25,000 mPa.s;
- (B) a silicon-containing crosslinker for the siloxane base polymer system, wherein the crosslinker contains at least two --SiH groups per molecule;
- (C) a platinum group catalyst sufficient for curing a composition prepared by mixing components (A), and (B);
- and
- (E) a blowing agent.
Dependencies are inferred from the claim text.