Use of Non-Soap Particulate Antifoams

Reliance on the reaction of hardness ions with soap or alkyl phosphate ions to form calcium soap or calcium alkyl phosphate precipitates for foam control has an obvious limitation in the case of soft water. This factor has encouraged a search for alternative materials that can also form finely divided hydrophobic particles. Hydrocarbon waxes represent an obvious choice in this context. 

Other particulate antifoams, which should function effectively in soft water, have been suggested as alternatives to calcium soaps. These have included monalkyl-amides [16, 17] and melamine derivatives [18-26]. The former can apparently be introduced directly into the detergent slurry before it is spray-dried. The latter is first emulsified using snitable surfactant whereupon it can either be directly sprayed onto the detergent powder or be sprayed onto a carrier, which can be subsequently incorporated. 

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