Patent ID: 7619043

Claim:
A defoamer composition, comprising: (A) at least one organosilicon compound comprising units of the formula R a (R 1 O) b R 2 c SiO (4-a-b-c)/2 (I) in which R represents a methyl radical, R 1 each is identical or different and denotes a hydrogen atom or a monovalent, optionally substituted hydrocarbon radical, R 2 represents a phenyl radical which is attached to the silicon atom via a carbon ring atom, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3 and c is 0, 1, 2 or 3 with the proviso that the sum a+b+c is less than or equal to 3, and in 1-100% of all units of the formula (I) per molecule, c is other than 0, and in at least 50% of all of the units of the formula (I) in the organosilicon compound the sum a+b+c is 2, and 10 to 100% of SiC-bonded radicals in component (A) are radical R 2 , (B1) optionally, filler particles, and (B2) at least one organopolysiloxane resin comprising units of the formula R 3 d (R 4 O) e SiO (4-d-e)/2 (II) in which R 3 each is identical or different and denotes a hydrogen atom or a monovalent, optionally substituted, SiC-bonded hydrocarbon radical, R 4 each is identical or different and denotes a hydrogen atom or a monovalent, optionally substituted hydrocarbon radical, d is 0, 1, 2 or 3 and e is 0, 1, 2 or 3, with the proviso that the sum d+e≦3 and in less than 50% of all of the units of the formula (II) in the organopolysiloxane resin the sum d+e is 2, and, (C) optionally an organosilicon compound comprising units of the formula R 5 g (R 6 O) h SiO (4-g-h)/2 (III) in which R 5 each is identical or different and has a meaning given for R, R 6 each is identical or different and has a meaning given for R 1 , g is 0, 1, 2 or 3 and h is 0, 1, 2 or 3, with the proviso that the sum g+h≦3 and in at least 50% of all of the units of the formula (III) in the organosilicon compound the sum g+h is 2.