METHOD OF PREPARING AND USING COMPOSITIONS CONTROLLING FOAMING Russian patent published in 2011 - IPC B01D19/04 C08G77/04 C08L83/10 

FIELD: chemistry.

SUBSTANCE: inventions relate to preparation and use of compositions which control foaming, especially in aqueous media. The method of preparing a composition which contains polyorganosiloxane, in which filler with a hydrophobic surface is dispersed, involves a step (A) for mixing finely ground filler (i), polyorganosilixane (ii), having at least two reactive substitutes, and polyorganosiloxane (iii), having at least three reactive substitutes, and a step (B) for inducing hydrosilylation of components (ii) and (iii) in the presence of a transition metal based catalyst. The hydrosilylation reation is carried out until the reaction mixture is at least partially converted to a gel, and shearing forces are applied to the said mixture which is at least partially converted to gel. The reactive substitutes in (ii) are aliphatic unsaturated hydrocarbon groups, and in (iii) they are hydrogen atoms bonded with silicon, which are capable of entering into an addition reaction (ii) with the hydrosilylation component (iii). The method of controlling foam in an aqueous medium is realised using the composition which controls foaming.

EFFECT: composition improves capacity to control foam with high efficiency of defoaming activity for a period of time longer than in existing anti-foaming agents.

20 cl, 2 tbl, 9 ex