Photopolymerizable compositions featuring novel co-initiators

Abstract

Abstract A photopolymerizable composition, element and method of photopolymerizing the composition or element are disclosed wherein the composition comprises an addition polymerizable compound containing ethylenic unsaturation and a co-initiator including a photopolymerization activator and photosensitizer. In one aspect of the invention, the photosensitizer is selected to be a coumarin having an absorption maximum between about 250 and about 550 nm, and a <IMAGE> substituent in the 3-position wherein R1 is alkyl or alkenyl having 1-12 carbon atoms, or a carboxylic or heterocyclic group having 5-20 nuclear carbon and hetero atoms, the coumarin and the activator being present in an amount sufficient to provide, when the compound is coated, dried and exposed to a medium-pressure mercury light source, a speed which is at least about one-fifth that of the same composition coated, dried and exposed identically except with a co-initiator consisting of Michler's ketone and benzophenone. In another aspect of the invention, the activator is selected to have the structure: <IMAGE> wherein: J is -O-, -S- or a carbon-to-carbon bond; J1, J2, and J3 are each independently hydrogen; alkyl, alkoxy, or alkylthio having from 1 to 5 carbon atoms; aryloxy having from 6 to 10 carbon atoms; halogen; or any two of J1, J2, and J3 taken together comprise the atoms necessary to complete a 5- or 6-membered fused heterocyclic or aromatic ring; and Z is the number of atoms necessary to complete a heterocyclic or aromatic ring of from 4 to 6 ring atoms. This application is a division of Ser. No. 184,606 filed 9/5/80, now U.S. Pat. No. 4,289,844, which is a continuation-in-part of Ser. No. 49,661, filed 6/18/79, now abandoned.

Inventors

• 👤 Donald P. Specht
• 👤 Conrad G. Houle
• 👤 Samir Y. Farid

Bibliographic Details