A silicone antifoam emulsion is polydimethylsiloxane (with hydrophobic silica) dispersed in water for foam control, supplied at 10-50% active silicone. It is selected by application grade: food grade to FCC / 21 CFR 173.340, wastewater grade for aeration and digester foam, latex grade for waterborne coatings, and general process grade for textiles, pulp & paper and cleaning. RawSource supplies the grade and active level matched to your foam load, sourced to spec.
Grade selection — Application grade (active silicone %)
A silicone (PDMS) antifoam dispersed in water, supplied at 10-50% active silicone. The selection axis is the application grade — the same active chemistry is qualified to a food (FCC / 21 CFR), wastewater, latex/coatings or general-process standard, at the active level matched to the foam load. Higher active % gives more knockdown per dose; the compliance grade is set by where it is used, not by performance.
| Application grade (active silicone %) | Active silicone | Compliance / standard | Typical applications | Supply |
|---|---|---|---|---|
| Food grade | — | FCC; 21 CFR 173.340 | foam control in food & beverage processing — cooking, fermentation, washing, fillers | sourced-to-spec |
| Wastewater / water-treatment grade | — | industrial (process) | aeration-basin, digester and clarifier foam control in municipal and industrial wastewater | sourced-to-spec |
| Latex / waterborne coatings grade | — | industrial (process) | foam control in latex paints, adhesives and waterborne coatings without surface defects | sourced-to-spec |
| General industrial / process grade | 10-50 % | technical | broad process foam control — textiles, pulp & paper, fermentation, cleaning chemistries | in-stock |
Frequently Asked Questions
What active silicone level do I need in an antifoam emulsion?
Silicone antifoam emulsions are supplied at 10-50% active. A higher active level delivers more foam knockdown per dose, so heavy or persistent foam favours a higher-active grade dosed lower; light process foam can use a lower-active grade. The application grade — food, wastewater, latex or general process — sets the compliance standard separately from the active level.
Is there a food-grade silicone defoamer?
Yes. The food grade is qualified to the Food Chemicals Codex and 21 CFR 173.340 (defoaming agents) for use in food and beverage processing. It is the same silicone antifoam chemistry held to a food-contact standard; a grade-specific CoA and SDS ship with every order.
What is the CAS number for silicone antifoam emulsion?
The active polydimethylsiloxane is listed under CAS 63148-62-9 (PDMS mixtures). Because the emulsion is a graded formulation rather than a single molecule, the active silicone content (10-50%) and compliance standard vary by grade rather than having one fixed value.