| abstract |
Photopolymerization initiators of the general formula: <IMAGE> wherein R1 and R1' independently stand for a tertiary alkyl group or a tertiary aralkyl group and R2 and R2' independently stand for a hydrogen atom, a tertiary alkoxy group, or a tertiary aralkyloxy group are disclosed. They are useful for effecting polymerization of radically polymerizable unsaturated compounds. Tetra peroxy esters of benzophenone are preferred. |