Antifoam composition containing hydrocarbon-silicon copolymer, hydrophobic filler and hydrocarbon oil

Claim 1

A novel hydrocarbon oil based silicone antifoam composition comprising: (a) from 1 to 60 weight percent of a hydrocarbon-silicon copolymer with a percent CH 2 content in the range of from 30% to 70% inclusive, which hydrocarbon-silicon copolymer is soluble in a hydrocarbon carrier oil and is selected from the group consisting of (1) random or block copolymers of the general formula: ##STR15## (2) non-hydrolyzable ABA block copolymers of the general formula: ##STR16## (3) hydrolyzable ABA block copolymers of the general formula: ##STR17## (4) non-hydrolyzable AB z block copolymers of the general formula: ##STR18## and (5) hydrolyzable AB z block copolymers of the general formula: ##STR19## wherein R is an alkyl, aryl, aralkyl or alkaryl group containing from six to thirty carbon atoms, R', R" and R'" are individually selected from the group consisting of hydrogen or methyl, ethyl, propyl, hydroxy, and phenyl groups provided that no more than 5% of the total R', R" and R'" groups are hydrogen hydroxy, phenyl or a combination thereof, and x,y,z and n are such a value so that the overall % CH 2 content is in the range of from 30% and 70% (b) from 1 to 20 weight percent of an hydrophobic filler having a particle size on the average of 200 to 5,000 A; (c) from 0 to 25 weight percent of a organo-silicone surfactant of the general formula: ##STR20## wherein R, R' and R" are individually alkyl groups having from 1 to 18 carbon atoms inclusive, or hydrogen, hydroxy or phenyl groups provided that no more than 5% of the total R, R' and R" groups are hydrogen, hydroxy, phenyl or a combination thereof. P is either a polyoxyethylene group, a polyoxypropylene group, a polyoxybutylene group or a mixture thereof which can be terminated with either an alkyl or hydroxyl group, l and m are such that the surfactant is liquid, has limited solubility and an HLB of from 4-14; and x has a value of from 2 to 5 (d) from 20 to 98 weight percent of a hydrocarbon carrier oil; and (e) optionally from 0 to 20 weight percent of a silicone oil.