| 摘要 |
The invention relates to defoamer formulations which comprise (A) siloxane-based antifoam agents and (B) polysiloxane copolymers which are obtainable by reacting, in a first step, organopolysiloxanes (1) which comprise at least one Si-bound hydrogen atom, preferably at least two Si-bound hydrogen atoms, per molecule, with the substantially linear oligomer or polymer compounds (2) of the general formula R1-(A-CnH2n)m-A1-H (I), wherein R1 represents a monovalent optionally substituted hydrocarbon group to which Si-H groups can be attached in a hydrosilylation reaction, preferably a hydrocarbon group comprising an aliphatic C-C multiple bond, A represents a divalent, polar organic group selected from the group comprising-O-,-C(O)-O-,-O-C(O)-,-O-C(O)-O-,-C(O)-NH-,-NH-C(O)-, a urethane group and a urea group, preferably an oxygen atom-O-, A 1 represents a divalent, polar organic group selected from the group comprising-O-,-NH-and-NR'-(whereby R' represents a monovalent hydrocarbon group with 1 to 18 carbon atoms), n is an integer from 1 to 20 and m is a positive integer, and, in a second step, reacting the intermediate products (4) so obtained which comprise H-A1 groups with organic compounds (5) having at least two isocyanate groups per molecule, with the proviso that the water content of the compounds (1) and (2) used for producing the polysiloxane copolymers is less than 2000 % ppm, based on the total weight of compounds (1) and (2).
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