Photoimaging process for forming multicolor images

Claim 1

In a process for forming a multicolor image by photopolymerizing comprising: 1. laminating to a receptor surface a photopolymerizable element comprising a support that transmits actinic radiation and a photopolymerizable layer so as to form a laminated structure having the photopolymerizable layer contiguous to the receptor surface, the receptor surface having greater adhesion to the photopolymerizable layer in both its polymerized and unpolymerized states than does the support; 2. exposing the layer imagewise through the support to actinic radiation to selectively raise the stick temperature of those areas receiving the radiation; 3. removing the support without transfer thereto of either exposed or underexposed areas of the photopolymerizable layer; 4. applying colorant material to the surface of the layer; 5. distributing the colorant material over the image surface whereby the distributed colorant material becomes embedded solely in the underexposed areas; 6. physically removing colorant material from the exposed image areas which are left substantially free of the colorant material; and 7. repeating said steps of laminating, exposing, removing, applying, distributing and removing one or more times, each succeeding photopolymerizable element having its photopolymerizable layer contiguous to the exposed and colored surface of the last previously laminated photopolymerizable layer; the improvement wherein the photopolymerizable element comprises a polyethylene terephthalate support which is surface treated by electrical discharge at the rate of 1.0 to 6.0 joules/inch 2 , the treated surface bearing the photopolymerizable layer which comprises a free radical initiated, chain propagating, addition polymerizable compound taken from the group consisting of trimethylolpropanetrimethacrylate, polyoxyethylatedtrimethylolpropanetriacrylate, and a mixture of polyoxyethylatedtrimethylolpropanetriacrylate and one of the addition polymerizable compounds taken from the group consisting of trimethylolpropanetrimethacrylate, trimethylolpropanetriacrylate, pentaerythritoltriacrylate, tetraethyleneglycoldiacrylate and tetraethyleneglycoldimethacrylate, at least one compatible organic polymeric acrylate ester binder and optionally a polyvinyl acetate binder which may be present in a weight ratio of less than 4 to 3 with respect to the acrylate ester binder component, and an addition polymerization initiator or initiator system activatable by actinic radiation.