Microwave cured silicone elastomeric foam
AssigneeDow Corning Corporation
InventorsChi-long Lee, Sherwood Spells
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Abstract
A simplified method of manufacturing a silicone elastomeric foam comprises mechanically generating a stable froth of an aqueous emulsion, while adding surfactant and thickener, then exposing the stable froth to microwave energy to remove the water. The emulsion consists essentially of anionically stabilized hydroxyl endblocked polydiorganosiloxane, colloidal silica, an organic tin compound, and water, the emulsion having a pH in the range of 9 to 11.5 inclusive. The dried froth is an elastomeric, cellular structure possessing typical silicone elastomer heat stability and long-term aging stability.
Claims8
A method of drying a stable froth produced from an aqueous silicone emulsion suitable to provide an elastomeric product upon removal of the water comprising
- (i) mechanically generating a stable froth from a silicone emulsion comprising 100 parts by weight of anionically stabilized hydroxyl endblocked polydiorganosiloxane having an average molecular weight of greater than 10,000, in the form of an aqueous emulsion having a pH in the range of 9 to 11.5 inclusive;
- at least one part by weight colloidal silica;
- an organic tin compound;
- and water;
- adding sufficient anionic or nonionic surfactant and thickener to make the froth stable until the water is removed in step (ii), and then,
- (ii) exposing the stable froth to sufficient microwave energy to remove the water from the emulsion, thereby forming an elastomeric cured foam.
Dependencies are inferred from the claim text.