| abstract |
Effective and long lasting defoamer compositions are prepared by admixing an organopolysiloxanes, a hydrophilic silica, a hydrophobic silica, optionally an organopolysiloxanes resin, and optionally a water insoluble inorganic compound, at a temperature of 50° C. to 250° C. until the viscosity of the composition has decreased to at least half its original viscosity prior to heating. |