Defoaming agents and process of defoaming

摘要

Substantially water-insoluble silicic acid esters corresponding to the following general formula are used to foam inhibitors in foaming systems. In the above formula, X and Y represent the group -OR or a methyl group, R represents a polypropylene glycol ether group and, optionally, a polyethylene glycol ether group which may be substituted by alkoxyl, amino-alkyl, acyl, acylamino, dialkoxyl and oxyaminoalkyl groups containing from 4 to 24 carbon atoms. The total number of glycol ether groups amounts to between 1 and 100, the number of polypropylene glycol ether groups preferably being at least equal to or larger than the number of ethylene glycol ether groups.