Photopolymerizable mixture, photosensitive recording element containing this mixture, and the production of lithographic printing plate using this photosensitive recording element

Claim 1

A photopolymerizable mixture consisting essentially of (i) from 5 to 99.5% by weight, based on the photopolymerizable mixture, of one or more ethylenically unsaturated, photopolymerizable compounds selected from the group consisting of monomers of a molecular weight of less than 1,000; oligomers of a mean molecular weight (number average) of from about 1,000 to about 10,000; and polymers of a mean molecular weight (number average) of from about 10,000 to about 250,000; said monomers, oligomers and polymers all containing one or more photopolymerizable double bonds; (ii) from 0.5 to 15% by weight based on the photopolymerizable mixture, of a photopolymerization initiator consisting essentially of (a) from 0.1 to 5% by weight, based on the photopolymerizable mixture, of one or more compounds of the formula (I) ##STR4## where A and B are --NR 1 R 2 , wherein R 1 and R 2 are identical or different and independently of one another are each hydrogen or an unsubstituted or substituted aliphatic, aromatic or mixed aliphatic-aromatic radical, X is oxygen, sulfur or ═NR 4 , wherein R 4 is hydrogen or an aliphatic, aromatic or mixed aliphatic-aromatic radical, Y is a direct bond or a --CH 2 --, --CH 2 --CH 2 --, --O--, --S--, --C(O)-- or NR 5 wherein R 5 is hydrogen or an aliphatic or aromatic radical and n is 0 or 1, and (b) from 0.4 to 10% by weight, based on the photopolymerizable mixture, of one or more compounds of the formula (II) ##STR5## where R 6 , R 7 and R 8 are identical or different and are each unsubstituted or substituted alkyl, unsubstituted or substituted aryl or unsubstituted or substituted aralkyl, and one or more of the radicals R 6 , R 7 , and R 8 are monohalogen-, dihalogen- or trihalogen-substituted methyl and one of the radicals R 6 , R 7 , or R 8 may furthermore be unsubstituted or substituted alkenyl or --NR 2 , --OR-- or --SR--, where R in each case is hydrogen, alkyl or aryl, the weight ratio of compounds of the formula (I) to the compounds of the formula (II) in the polymerizable mixture being from 10:90 to 40:60; and (iii) from 0 to 90% by weight, based on the photopolymerizable mixture, of a film-forming nonphotopolymerizable polymeric binder.