Patent ID: 8084552

Claim:
A method for producing silicone polyethers, comprising reacting (i) in a first step unsaturated polyethers (3) of the formula where R 1 is a hydrogen atom or a hydrocarbyl radical having 1 to 6 carbon atoms, a is 0 or an integer from 1 to 16, b is 0 or an integer from 1 to 50, and c is 0 or an integer from 1 to 50, with organopolysiloxanes (1), which contain from 0.2% to 1.6% by weight of silicon bonded hydrogen, and (ii) in a second step, adding organopolysiloxanes (2), which contain from 0.02% to 1.0% by weight of silicon bonded hydrogen, the percent by weight of silicon bonded hydrogen in a organopolysiloxanes (2) being less than the percent by weight of silicon bonded hydrogen in organopolysiloxanes (1), to the reaction mixture of the first step and reacting the organopolysiloxanes (2) with a product mixture produced in the first step, with the proviso that reacting in the first and second steps is carried out in the presence of at least one catalyst (4) which promotes the addition of silicon bonded hydrogen onto an aliphatic double bond, and the ratio of the weight concentration of silicon bonded hydrogen in organopolysiloxane (1) to the weight concentration of silicon bonded hydrogen in organopolysiloxane (2) is at least 0.9 and wherein the conversion of silicon bonded hydrogen groups is at least 94% after 3.5 hours at 100° C.