ABSTRACT
A large number of fluids are used in formulating antifoams. In the 1950s a new class of antifoams, which was based on silicone fluids, was developed. The cost limitations of silicone antifoams were partially offset in a new set of antifoams developed in the 1960s. For protein-stabilized foam all the antifoams, including silicone/silica, are listed as being effective but will, naturally, have differing efficiencies. The active mixture preparation requires dispersion of hydrophobic silica or other finely divided solid in silicone oil. The preparation of silicone antifoams, although seemingly easy, is complicated by the fact that there are numerous variables, demonstrated empirically, that can affect antifoam performance. The viscosity of silicone oil used in the preparation of antifoam has a major effect on the overall effectiveness of the resulting composition. Antifoaming, using filled silicone oil-based antifoams, is a complex process that involves, at least, the following steps, all of which contribute to the overall performance.
