NTP Research Concept: Phenolic Benzotriazoles

These chemicals are used as UV stabilizers within products to increase stability to light. As industrial additives, they are used in paints, rubber, plastic, and electronic products. Some PBZTs are used in food contact polymers and adhesives, cosmetics, sunscreens, and fragrances. Generally speaking, the class is made up of chemicals with single substitutions on the phenolic ring (R2), double substitutions on the phenolic ring, double substitutions on the phenolic ring that includes an ester bond, and a collection of other PBZTs with various substitutions (multiphenolic rings, an octrizole dimer (bisoctrizole), etc.). A few PBZTs have chlorine substitutions at the R3 position. Production of these chemicals ranges from unknown production up to ten million pounds per year. Twenty nine chemicals have been identified in this class, but this concept will focus primarily on the ten PBZTs with production values reported under the latest US Environmental Protection Agency’s Inventory Update Rule (IUR) (table below).