Zinc borate is primarily used as a flame retardant in plastics and cellulose fibers, paper, rubbers and textiles. It is also used in paints, adhesives, and pigments.
As a flame retardant, it can replace antimony(III) oxide as a synergist in both halogen-based and halogen-free systems. It is an anti-dripping and char-promoting agent, and suppresses the afterglow. In electrical insulator plastics it suppresses arcing and tracking.