Stearalkonium Chloride

Stearalkonium chloride (CAS 122-19-0) is a quaternary ammonium cationic surfactant — the "stearyl" (C18) analog of benzalkonium chloride. The full chemical name is benzyldimethyl(octadecyl)ammonium chloride. In rinseless and waterless wash formulas it functions as a substantive surfactant: the positively-charged head group binds lightly to the slightly-negative paint surface, leaving behind a thin antistatic layer that helps repel airborne dust. At typical in-product concentrations of 0.5–3% in the concentrate, no Cat-1 H-codes apply at the mixture level (no corrosion, no respiratory sensitization). Cationic surfactants in this family do contribute to aquatic toxicity at concentrate strength — biodegradability is moderate (not "readily biodegradable" per OECD 301, but does break down through adsorption to wastewater-treatment biomass). At the 1:256 working dilution typical of rinseless wash, the in-bucket concentration is well below aquatic toxicity thresholds.