Antimony trioxide

Antimony trioxide (CAS 1309-64-4), also known as Flowers of Antimony, is a flame retardant synergist used across plastics, textiles, and industrial materials. It does not act as a standalone flame retardant.

Instead, it amplifies the performance of halogenated flame retardant systems, allowing formulators to achieve target fire ratings at lower total additive loadings. In plastics and polymers, it is compounded with brominated or chlorinated flame retardants.

This process helps materials meet UL 94 and other flammability standards in wire insulation, connectors, and housings. Textile and fabric coatings for automotive interiors, upholstery, and protective workwear rely on it to pass certifications.

In construction materials, it is incorporated into PVC profiles, roofing membranes, and wall panels where building codes mandate flame resistance. Electronics manufacturers use it in printed circuit board laminates and encapsulant compounds.

These applications help to control flame spread in high-density assemblies. Antimony trioxide is supplied as a fine white powder in standard and high-purity grades for various industrial needs.

Technical and flame retardant grades are the most common commercial forms, with particle size specifications varying by application. Finer grades are preferred for film and fiber applications.

Bulk bags and small-pack options are standard across the supply chain. This ensures that manufacturers can source the material in the quantities required for their specific production processes.