Polymeric sensitizers for photopolymer composition

A photopolymerizable composition consisting essentially of

• (A) at least one nongaseous ethylenically unsaturated compound having at least one terminal ethylenically unsaturated group, a boiling point above 100.degree. C. at normal atmospheric pressure and being capable of addition polymerization;
• (B) at least one 2,4,5-triarylimidazolyl dimer consisting of two lophine radicals bound together by a single covalent bond;
• (C) at least one polymeric sensitizer sensitive to ultraviolet or visible radiation and having a weight average molecular weight in the range of 10,000 to 300,000, the polymeric sensitizer being the reaction product of
• (1) a reactive sensitizer moiety of the formula:
• ##STR11## wherein R.sub.1 is alkyl of 1 to 12 carbon atoms:
• R.sub.2 is alkyl of 1 to 12 carbon atoms, --CH.sub.2 CH.sub.2 Cl;
• R.sub.3 is H, and with the proviso that when R.sub.2 is not --CH.sub.2 CH.sub.2 Cl, R.sub.3 can be one of --O(CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 OH, --O(CH.sub.2 CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 CH.sub.2 OH wherein n is 0 to 10, --OCH.sub.2 CH.sub.2 NH.sub.2, --(CH.sub.2).sub.n OH, --(CH.sub.2).sub.n NH.sub.2 wherein n is 1 to 12;
• and
• R.sub.4 is H, and with the proviso that when R.sub.2 is not --CH.sub.2 CH.sub.2 Cl and R.sub.3 is H, R.sub.4 is one of --O(CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 OH, --O(CH.sub.2 CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 CH.sub.2 OH wherein n is 0 to 10, --OCH.sub.2 CH.sub.2 NH.sub.2, --(CH.sub.2).sub.n OH, --(CH.sub.2).sub.n NH.sub.2 wherein n is 1 to 12;
• ##STR12## wherein Z is --CH.sub.2 --;
• --CH.sub.2 CH.sub.2 --;
• --CH.sub.2 O-- with oxygen bonded to the aromatic ring;
• R.sub.5 is alkyl of 1 to 12 carbon atoms;
• R.sub.6 is alkyl of 1 to 12 carbon atoms, --CH.sub.2 CH.sub.2 Cl;
• R.sub.7 is H, --OCH.sub.3, and with the proviso that when R.sub.6 is not --CH.sub.2 CH.sub.2 Cl, R.sub.7 can be one of --O(CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 OH, --O(CH.sub.2 CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 CH.sub.2 OH wherein n is 0 to 10, --OCH.sub.2 CH.sub.2 NH.sub.2, --(CH.sub.2).sub.n OH, --(CH.sub.2).sub.n NH.sub.2 wherein n is 1 to 12;
• and
• R.sub.8 is H, --OCH.sub.3, and with the proviso that when R.sub.6 is not --CH.sub.2 CH.sub.2 Cl and R.sub.7 is H or --OCH.sub.3, R.sub.8 is one of --O(CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 OH, --O(CH.sub.2 CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 CH.sub.2 OH wherein n is 0 to 10, --OCH.sub.2 CH.sub.2 NH.sub.2, --(CH.sub.2).sub.n OH, --(CH.sub.2).sub.n NH.sub.2 wherein n is 1 to 12;
• ##STR13## wherein R.sub.5 is alkyl of 1 to 12 carbon atoms;
• R.sub.6 is alkyl of 1 to 12 carbon atoms, --CH.sub.2 CH.sub.2 Cl;
• R.sub.7 is H, --OCH.sub.3, and with the proviso that when R.sub.6 is not --CH.sub.2 CH.sub.2 Cl, R.sub.7 can be one of --O(CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 OH, --O(CH.sub.2 CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 CH.sub.2 OH wherein n is 0 to 10, --OCH.sub.2 CH.sub.2 NH.sub.2, --(CH.sub.2).sub.n OH, --(CH.sub.2).sub.n NH.sub.2 wherein n is 1 to 12;
• and
• R.sub.8 is H, --OCH.sub.3, and with the proviso that when R.sub.6 is not --CH.sub.2 CH.sub.2 Cl and R.sub.7 is H or --OCH.sub.3, R.sub.8 is one of --O(CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 OH, --O(CH.sub.2 CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 CH.sub.2 OH wherein n is 0 to 10, --OCH.sub.2 CH.sub.2 NH.sub.2, --(CH.sub.2).sub.n OH, --(CH.sub.2).sub.n NH.sub.2 wherein n is 1 to 12;
• and
• (2) a reactive polymer taken from the group consisting of methyl methacrylate, methyl acrylate, isocyanatoethyl methacrylate, maleic anhydride, chloromethyl styrene, p-hydroxystyrene, acrylic acid, methacrylic acid, phenolformaldehyde resins, epoxy polymers, and mixtures of said polymers, the polymeric sensitizer having 0.1 to 70% by weight of the sensitizer moiety;
• and
• (D) 0 to 97 parts by weight of at least one organic polymeric binder relative to 3 to 100 parts by weight of ethylenically unsaturated compound (A);
• component (B) being present in an amount of 0.001 to 20 parts by weight per 100 parts by weight of the combined weight of components (A) and (D);
• and component (C) being present in an amount of 0.1 to 80% by weight based on the total dry weight of the composition.