Patent ID: 6686320
Filing Date: 2004-02-03
Classification: B01D

Abstract:
A defoaming composition which comprises a water-insoluble polyoxyalkylene-polysiloxane block copolymer of the average general formula whereR1 and/or R7 are R2 or â€”[R4]wâ€”[R5]xâ€”R6â€”R8, R2 and R3 are identical or different alkyl radicals or are unsubstituted or substituted aryl radicals, R4 is a divalent radical of the formula â€”Oâ€”, â€”NHâ€”, â€”NR2â€”, â€”Sâ€”or of the formula â€”[Oâ€”Si(CH3)2]uâ€”, whereu is from 2 to 200, R5 is identical or different alkylene radicals having 1 to 24 carbon atoms, or is â€”CnH2n-fR2fâ€”Oâ€”CmH2m-gR2gâ€”, where, f is from 0 to 12, g is from 0 to 12, n is from 1 to 18, m is from 1 to 18, R6 is identical or different radicals of the general formula â€”Oâ€”(C2H4O)a(CH2â€”CH(CH3)O)b(CH2â€”CR9R10O)câ€”, whereR9 and R10 are a methyl radical, or R9 is a hydrogen atom and R10 is an ethyl radical, but where, taking into account all radicals R6, the proportion of C2H4O groups among the total of all radicals R6 does not exceed 40% by weight, a is from 2 to 30, b is from 2 to 50, c is from 2 to 40, and the sum (a+b+c) is from 6 to 100 and the sequence of the individual polyoxyalkylene segments â€”(C2H4O)aâ€” and â€”(CH2â€”CH(CH3)O)bâ€” and â€”(CH2CR9R10O)câ€” is either random or block or combination thereof, R8 is a hydrogen, a substituted or unsubstituted alkyl radical or an acyl radical, v is from 3 to 200, w is 0 or 1, x is 0 or 1, y is from 0 to 200, and, if y is 0, R1 and/or R7 are/is â€”[R4]wâ€”[R5]xâ€”R6â€”R8; a nonionic ethoxylate having a HBL from 8 to 11 and, optionally, a solid; whereby said polysiloxane block copolymer is greater than 90% by weight of all polysiloxane block copolymers in the defoaming composition.