Foamable siloxane compositions and silicone foams prepared therefrom
AssigneeDow Corning Corporation
InventorsBrian Paul Loiselle, Lawrence Joseph Rapson
Life of this patent
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Abstract
Foamable organosiloxane compositions which yield, upon cure, silicone foams having low density and decreased friability, comprising a siloxane base polymer having an average of at least two hydroxyl groups per molecule; a silicon-containing crosslinker for the siloxane base polymer, wherein the crosslinker contains at least two --SiH groups per molecule; a platinum group catalyst; a silicone resin copolymer; and optionally, a blowing agent; and silicone foams prepared therefrom. A method of weather-stripping a door or window using a silicone foam so prepared.
Claims17
A foamable organosiloxane composition, comprising:
- (A) a siloxane base polymer containing an average of at least two hydroxyl groups per molecule;
- (B) a silicon-bonded hydrogen atom-containing crosslinker for the siloxane base polymer, wherein the crosslinker contains at least two --SiH groups per molecule;
- (C) a platinum group catalyst sufficient for curing the foamable organosiloxane composition;
- and
- (D) a silicone resin copolymer consisting essentially of (R.sup.3).sub.3 SiO.sub.1/2 units and SiO.sub.2 units, wherein R.sup.3 is an alkyl group.
The product obtained from the incipient materials:
- (A) a siloxane base polymer containing an average of at least two hydroxyl groups per molecule;
- (B) a silicon-bonded hydrogen atom-containing crosslinker for the siloxane base polymer, 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);
- (D) a silicone resin copolymer consisting essentially of (R.sup.3).sub.3 SiO.sub.1/2 units and SiO.sub.2 units, wherein R.sup.3 is an alkyl group;
- and
- (E) a blowing agent.
A silicone foam prepared by
- (I) mixing a foamable organopolysiloxane composition comprising:
- (A) a siloxane base polymer containing an average of at least two hydroxyl groups per molecule;
- (B) a silicon-bonded hydrogen atom-containing crosslinker for the siloxane base polymer, wherein the crosslinker contains at least two --SiH groups per molecule;
- (C) a platinum group catalyst sufficient for curing the foamable organosiloxane composition;
- and
- (D) a silicone resin copolymer consisting essentially of (R.sup.3).sub.3 SiO.sub.1/2 units and SiO.sub.2 units, wherein R.sup.3 is an alkyl group;
- and
- (II) allowing the foamable organosiloxane composition to cure.
A silicone foam prepared by
- (I) preparing a mixture by mixing
- (B) a silicon-bonded hydrogen atom-containing crosslinker, having at least two --SiH groups per molecule;
- and
- (D) a silicone resin copolymer consisting essentially of (R.sup.3).sub.3 SiO.sub.1/2 units and SiO.sub.2 units, wherein R.sup.3 is an alkyl group;
- (II) preparing a foamable organosiloxane composition comprising:
- (A) a siloxane base polymer containing an average of at least two hydroxyl groups per molecule;
- (C) a platinum group catalyst sufficient for curing the foamable organosiloxane composition;
- and
- the mixture prepared in step (I);
- and
- (III) allowing the foamable organosiloxane composition to cure;
- wherein component (B) is a crosslinker for the siloxane base polymer.
Dependencies are inferred from the claim text.