US 4,639,489 AGranted

Method of producing a silicone defoamer composition

AssigneeDow Corning Corporation

InventorsKoichi Aizawa, Shingo Sewa, Hideki Nakahara

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Abstract

Foam control compositions are prepared by reacting a mixture of components which include a polyorganosiloxane fluid bearing one or more hydroxyl and/or hydrocarbonoxy groups, a resinous siloxane or a silicone resin-producing silicon compound, a finely divided filler material and a catalyst to promote the reaction of the listed components. The compositions can optionally contain a polyorganosiloxane fluid which is substantially free of reactive groups and/or a polyorganosiloxane fluid bearing two or more hydroxyl and/or hydrocarbonoxy groups.

Claims18

Dependent claims

A method of producing a silicone defoamer composition comprising reacting at a temperature of 50.degree. C. to 300.degree. C.:

(1) 0 to 100 parts by weight of a polyorganosiloxane having a viscosity of 20 to 100,000 cs at 25.degree. C. and being expressed by the general formula R.sub.a.sup.1 SiO.sub.(4-a)/2 in which R.sup.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.degree. C. expressed by the general formula R.sub.b.sup.2 (R.sup.3 O).sub.c SiO.sub.(4-b-c)/2 in which R.sup.2 is a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 10 carbon atoms, R.sup.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.sup.3 group in each molecule, said --OR.sup.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.sub.d.sup.4 SiX.sub.4-d in which R.sup.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.sub.3).sub.3 SiO.sub.1/2 and SiO.sub.2 units and having a (CH.sub.3).sub.3 SiO.sub.1/2 /SiO.sub.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.degree. C. and being expressed by the general formula R.sub.e.sup.8 (R.sup.9 O).sub.f SiO.sub.(4-e-f)/2 in which R.sup.8 is a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 10 carbon atoms, R.sup.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.sup.9 groups in each molecule at the end of a molecular chain.

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Dependencies are inferred from the claim text.

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Abstract

A method of producing a silicone defoamer composition comprising reacting at a temperature of 50.degree. C. to 300.degree. C.:

(1) 0 to 100 parts by weight of a polyorganosiloxane having a viscosity of 20 to 100,000 cs at 25.degree. C. and being expressed by the general formula R.sub.a.sup.1 SiO.sub.(4-a)/2 in which R.sup.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.degree. C. expressed by the general formula R.sub.b.sup.2 (R.sup.3 O).sub.c SiO.sub.(4-b-c)/2 in which R.sup.2 is a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 10 carbon atoms, R.sup.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.sup.3 group in each molecule, said --OR.sup.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.sub.d.sup.4 SiX.sub.4-d in which R.sup.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.sub.3).sub.3 SiO.sub.1/2 and SiO.sub.2 units and having a (CH.sub.3).sub.3 SiO.sub.1/2 /SiO.sub.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.degree. C. and being expressed by the general formula R.sub.e.sup.8 (R.sup.9 O).sub.f SiO.sub.(4-e-f)/2 in which R.sup.8 is a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 10 carbon atoms, R.sup.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.sup.9 groups in each molecule at the end of a molecular chain.

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