It is Benzotriazole UV Light Absorber.
Provides ultraviolet protection in a wide variety of polymers including styrene homo and
copolymers, engineering plastics such as polyesters and acrylic resins, polyvinyl chloride,
and other halogen containing polymers and copolymers (e.g. vinylidenes), acetals and
Elastomers, adhesives, polycarbonate blends, polyurethanes, and some cellulose esters
and epoxy materials also benefit from the use of it.
It features a strong absorption of ultraviolet radiation in the 300-400 nm region. It also
has a high degree of photostability over long periods of light exposure.
It also is an effective stabilizer against the effects of ultraviolet light.