| 摘要 |
(A) Siloxane-based antifoams and (B) silicone polyethers prepared by reacting organopolysiloxanes (1) containing 0.05% to 1.6% by weight of Si-bonded hydrogen atoms with unsaturated polyethers (3) of the formulae: CH2═CR1—(CH2)aO(C2H4O)bR1  (Ia) CH2═CR1—(CH2)aO(C2H4O)b(C3H6O)cR1  (Ib) CH2═CR1—(CH2)aO(C3H6O)cR1  (Ic), where R1 is a hydrogen or a C1-6 hydrocarbon radical, a is 0 to 16, b is 1 to 50, and c is 1 to 50, wherein the sum b+c is ≧10 and at least two different polyethers (Ia), (Ib) and (Ic) are used, and optionally further reacting the reaction product with organopolysiloxanes (2) containing from 0.01% to 0.5% by weight of Si-bonded hydrogen atoms, wherein the first and second step reactions take place with a hydrosilylation catalyst, and the weight ratio of Si-bonded hydrogen in organopolysiloxane (1) to Si-bonded hydrogen in organopolysiloxane (2) is at least 1.5. |
