Antifoaming compositions

A composition comprising

• (A) polysiloxane copolymers prepared by
• in a 1st step
• reacting organopolysiloxanes (1) which have per molecule at least one Si-bonded hydrogen atom, with substantially linear oligomeric or polymeric compounds (2) of the formula
• R1-(A-CnH2n)m-A1-H (I),
• where R1 is a monovalent, optionally substituted hydrocarbon radical, which is hydrosilylatable by Si-H groups in a hydrosilylation reaction,
• A is a divalent, polar organic radical selected from the group consisting of —O—, —C(O)-O—, —O—C(O)—, —O—C(O)-O—, —C(O)-NH-, -NH-C(O)-, urethane radicals and urea radicals, and mixtures thereof,
• A1 is a divalent, polar organic radical selected from the group consisting of —O—, -NH, -NR′-, and mixtures thereof where R′ is a monovalent hydrocarbon radical having 1 to 18 carbon atoms,
• n is an integer from 1 to 20, and
• m is an integer,
• with the proviso that the m units (A-CnH2n) are identical or different, to form intermediates (4) containing H-A′ groups, and
• in a 2nd step
• reacting the resultant intermediates (4) containing H-A′ groups, with organic compounds (5) which have per molecule at least two isocyanate groups, and also, optionally, with further compounds (7) which are reactive with isocyanate groups,
• (B) organopolysiloxane resins comprising units of the formula
• R8g(R9O)hSiO(4-g-h)/2 (VI),
• in which
• R8 are identical or different, and are hydrogen or a monovalent, optionally substituted, SiC-bonded hydrocarbon radical,
• R9 are identical or different and are hydrogen or a monovalent, optionally substituted hydrocarbon radical,
• 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 less than 50% of all of the units of the formula (VI) in the organopolysiloxane resin the sum g+h is 2,
• with the proviso that the composition does not contain polyorganosiloxanes in which more than 90% of the units are difunctional units of the formula SiR″2O2/2 where R′ is a hydrocarbon radical.