Method of producing a silicone defoamer composition

Claim 1

A method of producing a silicone defoamer composition comprising reacting at a temperature of 50° C. to 300° C.: (1) 0 to 100 parts by weight of a polyorganosiloxane having a viscosity of 20 to 100,000 cs at 25° C. and being expressed by the general formula R a 1 SiO.sub.(4-a)/2 in which R 1 is a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 10 carbon atoms and a has an average value of from 1.9 to 2.2; (2) 5 to 100 parts by weight of a polyorganosilxoane having a viscosity of 200 to several million cs at 25° C. expressed by the general formula R b 2 (R 3 O) c SiO.sub.(4-b-c)/2 in which R 2 is a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 10 carbon atoms, R 3 is hydrogen or a monovalent hydrocarbon group having 1 to 10 carbon atoms, b has an average value of from 1.9 to 2.2 and c has a sufficiently large value to give at least one --OR 3 group in each molecule, said --OR 3 group being present at least at the end of a molecular chain; (3) 0.5 to 20 parts by weight for every 100 parts by weight of said components (1) and (2) of one or more compounds selected from the following (a) to (d): (a) an organosilicon compound of the general formula R d 4 SiX 4-d in which R 4 is a monovalent hydrocarbon group having 1 to 5 carbon atoms, X is a hydrolyzable group and d has an average value of one or less; (b) a partially hydrolyzed condensate of said compound (a); (c) a siloxane resin consisting essentially of (CH 3 ) 3 SiO 1/2 and SiO 2 units and having a (CH 3 ) 3 SiO 1/2 /SiO 2 ratio of 0.4/1 to 1.2/1; and (d) a condensate of said compound (c) with said compound (a) or (b); (4) 0.5 to 30 parts by weight of a finely divided filler for every 100 parts by weight of said components (1) and (2); (5) a catalytic amount of a compound for promoting the reaction of the other components; and (6) 0 to 20 parts by weight, for every 100 parts by weight of said components (1) and (2), of a polyorganosiloxane having a viscosity of 5 to 200 cs at 25° C. and being expressed by the general formula R e 8 (R 9 O) f SiO.sub.(4-e-f)/2 in which R 8 is a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 10 carbon atoms, R 9 is hydrogen or a monovalent hydrocarbon group having 1 to 10 carbon atoms, e is from 1.9 to 2.2 on an average and f has a sufficiently large value to give at least two --OR 9 groups in each molecule at the end of a molecular chain.

Claim 2

A method of producing a silicone defoamer composition comprising reacting at a temperature of 50° C. to 300° C.: (1) 0 to 100 parts by weight of a polyorganosiloxane having a viscosity of 20 to 100,000 cs at 25° C. and being expressed by the general formula R a 1 SiO.sub.(4-a)/2 in which R 1 is a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 10 carbon atoms and a has an average value of from 1.9 to 2.2; (2) 5 to 100 parts by weight of a polyorganosilxoane having a viscosity of 200 to several million cs at 25° C. expressed by the general formula R b 2 (R 3 O) c SiO.sub.(4-b-c)/2 in which R 2 is a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 10 carbon atoms, R 3 is hydrogen or a monovalent hydrocarbon group having 1 to 10 carbon atoms, b has an average value of from 1.9 to 2.2 and c has a sufficiently large value to give at least one --OR 3 group in each molecule, said --OR 3 group being present at least at the end of a molecular chain; (3) 0.5 to 20 parts by weight for every 100 parts by weight of said components (1) and (2) of one or more compounds selected from the following (a) to (d): (a) an organosilicon compound of the general formula R d 4 SiX 4-d in which R 4 is a monovalent hydrocarbon group having 1 to 5 carbon atoms, X is a hydrolyzable group and d has an average value of one or less; (b) a partially hydrolyzed condensate of said compound (a); (c) a siloxane resin consisting essentially of (CH 3 ) 3 SiO 1/2 and SiO 2 units and having a (CH 3 ) 3 SiO 1/2 /SiO 2 ratio of 0.4/1 to 1.2/1; and (d) a condensate of said compound (c) with said compound (a) or (b); (4) 0.5 to 30 parts by weight of a finely divided filler for every 100 parts by weight of said components (1) and (2); (5) a catalytic amount of a compound for promoting the reaction of the other components; and (6) 0 to 20 parts by weight, for every 100 parts by weight of said components (1) and (2), of a polyorganosiloxane having a viscosity of 5 to 200 cs at 25° C. and being expressed by the general formula R e 8 (R 9 O) f SiO.sub.(4-e-f)/2 in which R 8 is a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 10 carbon atoms, R 9 is hydrogen or a monovalent hydrocarbon group having 1 to 10 carbon atoms, e is from 1.9 to 2.2 on an average and f has a sufficiently large value to give at least two --OR 9 groups in each molecule at the end of a molecular chain.