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 trioxide 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.
In halogen-containing systems, zinc borate is used together with
antimony trioxide and alumina trihydrate. It catalyzes formation of
char and creates a protective layer of glass. Zinc catalyzes the
release of halogens by forming zinc halides and zinc
oxyhalides.
