Low platinum content hydrosilylation reaction-crosslinkable silicone rubber powder
AssigneeDow Corning Toray Co., Ltd.
InventorMari WAKITA
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Abstract
A method to produce a hydrosilylation reaction-crosslinkable silicone rubber powder includes washing the hydrosilylation reaction-crosslinkable silicone rubber powder using an aqueous solution. The aqueous solution can be heated to a temperature of 30° C. to 99° C. The aqueous solution contains at least one type of surfactant. The hydrosilylation reaction-crosslinkable silicone rubber powder produced via the method has a platinum metal content ≦3.5 ppm by mass. The hydrosilylation reaction-crosslinkable silicone rubber powder can be used for various applications, including use in a cosmetic composition, which can also include a cosmetic raw material.
Claims20
A hydrosilylation reaction-crosslinkable silicone rubber powder having a platinum metal content ≦3.5 ppm by mass.
A method of producing a hydrosilylation reaction-crosslinkable silicone rubber powder, the method comprising:
- washing a silicone rubber powder containing at least 5 ppm by mass of platinum metal using an aqueous solution of at least one type of surfactant to lower platinum content in the silicone rubber powder;
- wherein the hydrosilylation reaction-crosslinkable silicone rubber powder produced has a platinum metal content ≦3.5 ppm by mass.
A method of producing a hydrosilylation reaction-crosslinkable silicone rubber powder, the method comprising
- (a) producing a silicone rubber powder by curing a composition comprising:
- (A) an organopolysiloxane having at least two alkenyl groups in a molecule;
- (B) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in a molecule;
- and
- at least 5.0 ppm by mass of a platinum-based catalyst, in terms of a platinum metal content, relative to the mass of a cured product resulting from crosslinking component (A) and component (B);
- and
- (b) washing at least once the silicone rubber powder using at least 50 parts by mass of an aqueous solution heated to a temperature of 30° C. to 99° C. containing at least 0.1% by mass of at least one type of surfactant, per 100 parts by mass of the silicone rubber powder,
- to obtain a silicone rubber powder having a platinum metal content ≦3.5 ppm by mass.
Dependencies are inferred from the claim text.