Antifoam compositions comprising branched siloxanes formed by treating linear siloxanes with high-energy radiation
AssigneeWacker Chemie AG
InventorsJohn Young, Hagit Ben-Daat Levin, Frank Achenbach
Life of this patent
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Abstract
A defoamer or anti-foam formulation and a process for preparing the same. The process includes in a first step, preparing branched organopolysiloxanes (A) by irradiating organopolysiloxanes (X) of the formula (1) R13-a(R2O)aSi—[OSiR32]n—OSi(OR2)aR13-a (1). Where with high-energy radiation, the viscosity of the organopolysiloxanes (A) is at least 40% higher than the viscosity of the organopolysiloxanes (X). In a second step, the branched organopolysiloxanes (A) are treated with a filler (B) which is selected from precipitated and/or fumed silicas, and organopolysiloxane resins (C).
Claims6
A process for preparing defoamer formulations, comprising:
- in a first step, preparing branched organopolysiloxanes (A) by irradiating organopolysiloxanes (X) with high-energy radiation in such a way that the viscosity of the organopolysiloxanes (A) is at least 40% higher than the viscosity of the organopolysiloxanes (X), wherein the organopolysiloxane (X) is of the formula (1):
- R13-a(R2O)aSi—[OSiR32]n—OSi(OR2)aR13-a (1),
- wherein R1 and R2 are independently monovalent unsubstituted or halogenated saturated or unsaturated alkyl or cycloalkyl radicals having up to 30 carbon atoms, or a hydrogen;
- wherein R3 is a methyl, ethyl, vinyl, octyl, or 2-propenylphenyl radical:
- wherein a is 0 or 1;
- wherein n is an integer and has a value such that the viscosity of the organopolysiloxanes (X) is 350-20,000 mPa sec at 25° C. and 1013 hPa;
- wherein in the formula (1) at most 0.22 mol % of a is 1 and R2 is H:
- and in a second step;
- treating the branched organopolysiloxanes (A) with filler (B) which is selected from precipitated and/or fumed silicas, and with organopolysiloxane resins (C).
Dependencies are inferred from the claim text.