PROCESS FOR DEFOAMING AQUEOUS COMPOSITIONS CONTAINING SURFACTANTS

摘要

What is described is a process for defoaming and/or preventing foaming of aqueous compositions containing surfactants by adding defoamer formulations containing: (A) polydiorganosiloxanes containing units of the formula (I) where: R may be the same or different and is a monovalent, optionally substituted hydrocarbyl radical having 1 to 36 carbon atoms; (B) wax-like &bgr;-ketocarbonyl-functional organosilicon compounds containing at least one Si-bonded B radical of the general formula R1CH2-C(=O)-CHR1-C(=O)-NH[-L2-NZ]y-L1-(Si) (II) where: R1 is a monovalent, optionally substituted hydrocarbyl radical having at least 12 carbon atoms; Z is a radical of the formula R1CH 2-C(=O)-CHR1-C(=O)- or a R2 radical; R2 is a hydrogen atom or a monovalent hydrocarbyl radical having 1 to 18 carbon atoms; L1 is a divalent hydrocarbyl radical having 1 to 18 carbon atoms; L2 is a divalent hydrocarbyl radical having 1 to 18 carbon atoms; y is 0 or 1; and (Si)- is the bond to the silicon atom.