PHOTOSENSITIVE PRINTING PLATE FOR NON-WATER OFFSET PRINTING

摘要

PURPOSE: To obtain a printing plate for nonaqueous offset printing having good image resolution, increased long time printing numbers and high photosensitivity by incorporating a compd. which is polymerized by a free radical and a polymn. initiator which forms the free radical under the effect of irradiation with chemical rays into a photosensitive layer contg. the condensation polymn. product of a diazonium salt. CONSTITUTION: The printing plate having the photosensitive layer composed of the condensation polymn. product of the diazonium salt and the photopolymerizable mixture composed of the polymerizable compd. and a photoreaction initiator has the photosensitivity higher than the photosensitivity of the printing plate having the layer consisting of only one piece of the photopolymerizable system. The condensation polymn. product of the diazonium salt consists of the repeating units of A-N2 X and B derived from a carbonyl compd. (where A is the residue of a compd. contg. arom. diazonium which can condense with formaldehyde and B is the residue of a compd. not contg. diazonium group which can condense with formaldehyde).The polymerizable compd. is the acrylate or methacrylate of polyhydric alcohol. While many compds. are usable for the photoreaction initiator, the trichloromethyl compd. is more particularly advantageous.