A defoamer composition including a primary antifoam agent which includes a particulate-type material having a high surface area such as silica, a secondary antifoam agent for acting synergistically with the primary antifoam agent such as polydimethylsiloxane, a water carrier, and a quaternary ammonium...http://www.google.de/patents/US5073298?utm_source=gb-gplus-sharePatent US5073298 - Antimicrobial antifoam compositions and methods
