# US 5,708,043 A · Foamable siloxane compositions and silicone foams prepared therefrom > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,708,043 A - Document ID: US5708043A - Status: Granted - Kind: A - Application number: 08/767,927 - Filed: 1996-12-17 - Granted: 1998-01-13 - Earliest claimed: 1996-12-17 - Assignees: Dow Corning Corporation - Inventors: Brian Paul Loiselle; Lawrence Joseph Rapson - Web page: https://patentgrep.com/patent/US5708043A ## CPC - C08J 9/142: {Compounds containing oxygen but no halogen atom} - B60J 10/15: characterised by the material - C08J 9/02: using blowing gases generated by the reacting monomers or modifying agents during the preparation or modification of macromolecules - C08J 2383/04: Polysiloxanes - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - B60J: WINDOWS, WINDSCREENS, NON-FIXED ROOFS, DOORS, OR SIMILAR DEVICES FOR VEHICLES; REMOVABLE EXTERNAL PROTECTIVE COVERINGS SPECIALLY ADAPTED FOR VEHICLES (fastening, suspending, closing, or opening of such devices E05) ## 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. ## Claims ### Claim 1 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. ### Claim 2 (depends on 1) The foamable organosiloxane composition of claim 1 further comprising (E) a blowing agent. ### Claim 3 (depends on 2) The foamable organosiloxane composition of claim 2 wherein the blowing agent is selected from the group consisting of water, monofunctional alcohols and polyols. ### Claim 4 (depends on 1) The foamable organosiloxane composition of claim 1 where component (A) has the general formula: ##STR4## wherein each R is individually selected from the group consisting of methyl, 3,3,3-trifluoropropyl and phenyl, R.sup.1 is R or a hydroxyl radical, m.gtoreq.0 and the value of n is selected such that the resulting polyorganosiloxane has an average of at least two hydroxyl groups. ### Claim 5 (depends on 4) The foamable organosiloxane composition of claim 4 wherein each R.sup.1 is a hydroxyl group. ### Claim 6 (depends on 1) The foamable organosiloxane composition of claim 1 wherein component (B) contains an average of at least three silicon-bonded hydrogen atoms per molecule. ### Claim 7 (depends on 1) The foamable organosiloxane composition of claim 1 wherein the weight ratio of component (A) to component (B) is from 16:1 to 2:1. ### Claim 8 (depends on 1) The foamable organosiloxane composition of claim 1 wherein component (D) is present in an amount ranging from 7.5 to 35 parts by weight per 100 parts of component (A). ### Claim 9 (depends on 1) The foamable organosiloxane composition of claim 1 wherein R.sup.3 is an alkyl group having 1 to 4 carbon atoms. ### Claim 10 (depends on 9) The foamable organosiloxane composition of claim 9 wherein R.sup.3 is a methyl group. ### Claim 11 (depends on 8) The foamable organosiloxane composition of claim 8 wherein component (D) contains from 1 to 5 weight percent hydroxyl group. ### Claim 12 (depends on 8) The foamable organosiloxane composition of claim 8 wherein component (D) contains from 2.4 to 2.9 weight percent hydroxyl group. ### Claim 13 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. ### Claim 14 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. ### Claim 15 (depends on 14) The silicone foam of claim 14, wherein the foamable organosiloxane composition further comprises (E) a blowing agent. ### Claim 16 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. ### Claim 17 (depends on 16) The silicone foam of claim 16, wherein the foamable organosiloxane composition further comprises (E) a blowing agent.