Stearyltrimethylammonium chloride

Stearyltrimethylammonium chloride (CAS 112-03-8), commonly abbreviated as STAC, is a quaternary ammonium cationic surfactant derived from stearic acid. It functions as a conditioning agent, biocide, and emulsifier across personal care, textile, and industrial processing applications. In personal care formulations, STAC deposits onto negatively charged hair and skin surfaces to deliver conditioning, detangling, and softening effects in rinse-off and leave-on products. Textile and leather processors use it as a fabric softener and fiber lubricant.

This chemical reduces static charge and improves handle in finishing baths. Water treatment operations employ STAC for its biocidal activity against bacteria and algae in industrial cooling systems and process water. In metalworking and lubricant formulations, it acts as an emulsifier and anti-corrosion additive, improving the stability of cutting fluids and protective coatings. This versatility makes it a staple in industrial chemical manufacturing.

Stearyltrimethylammonium chloride is supplied as a white to off-white paste or flakes, and as aqueous solutions at varying active concentrations. Technical and cosmetic grades are the most commonly available for industrial use. Cosmetic-grade material meets purity requirements for personal care use. Packaging typically ranges from drums to IBC containers depending on grade and concentration. Proper storage ensures the stability of the surfactant over time.