4-phenyl benzophenone

This is one of its primary and most significant uses. 4-Phenylbenzophenone acts as a Type II photoinitiator in UV-curable coatings, inks (especially for packaging, including food packaging, subject to specific regulatory compliance), and adhesives. When exposed to ultraviolet (UV) light, it absorbs light energy and generates free radicals, which then initiate the polymerization (curing) process. This leads to rapid hardening and improved durability of the material. It's often used in combination with other photoinitiators or co-initiators (like tertiary amines) to enhance efficiency, particularly for pigmented or colored formulations due to its long-wave absorbing molecular structure.