Release compound in negative acting photopolymerizable element

Claim 1

In a solvent-developable negative acting radiation sensitive photopolymerizable element comprising a support bearing a layer of negative acting photopolymerizable composition, useful in making printed circuits, and a cover sheet, said composition comprising: (a) at least one addition polymerizable ethylenically unsaturated compound having a boiling point above 100° C. at normal pressure; (b) an organic free radical-generating addition polymerization initiator activatable by actinic radiation in the ultraviolet-to-visible region of the spectrum and (c) a macromolecular organic polymeric binder, the improvement rendering the composition readily releasable from the cover sheet which comprises a release compound or mixture of the formula A-B wherein A is substituted or unsubstituted alkyl or alkenyl of 6 to 24 carbon atoms, and B is selected from the group consisting of an unsubstituted 5 or 6 atom aromatic or nonaromatic heterocyclic radical containing 2 or 3 heteroatoms taken from N, O, S or combination thereof, a hetercyclic radical having as the sole heterocyclic nucleus a 5 or 6 atom aromatic or nonaromatic heterocyclic nucleus containing 2 or 3 heteratoms taken from N,O,S or combination thereof, said nucleus substituted with a six carbon fused aromatic ring containing no substituents other than hydrogen, an alkali metal salt of a β amino carboxylic acid or a bis alkali metal salt of a β, β' amino dicarboxylic acid, wherein said release compound or mixture is present in said negative acting photopolymerizable composition in an effective amount sufficient to lower peel force to a value not greater than 75 grams.