Silicone oil compound for defoaming agent and defoaming agent composition

Abstract

Provided are an oil compound having a favorable initial defoaming property, and an excellent sustained defoaming capability due to a small level of deterioration with time, even in an alkaline foamed liquid in particular; and a defoaming agent composition containing such oil compound. The oil compound is a silicone oil compound (A) for a defoaming agent, which is a crosslink-treated product of: (a) 100 parts by mass of a hydrophobic organopolysiloxane having a viscosity of 10 to 100,000 mm2/s at 25° C.; and (b) 1 to 15 parts by mass of a fine powder silica, wherein in a particle size distribution of the organopolysiloxane-silica crosslinked product that is measured by single particle optical sizing (SPOS method) after diluting the oil compound with toluene, a median particle size on volumetric basis is 5 to 25 μm.

Dependencies are inferred from the claim text.