| 摘要 |
<p>Material for electrophotographically producing printing forms or printed circuits consists of an electrically conducting substrate and of a photoconductive insulating layer of a polymeric condensn. prod. of HCHO or paraformaldehyde and >=1 multinuclear carboxyclic aromatic cpd., in mixt. with >=1 activator and binder. The condensn. prod. consists of recurring non-crosslinked units having formula (I) and/or (II). (where X1 and X2 are H, 1-4C alkyl or alkoxy or halogen; X3 and X4 are 1-4 C alkyl, alkoxy or halogen; and n is 6-10). The activator is an electron acceptor. Mol. ratio activator: monomer unit is (0.05-0.4):1, esp. 0.1-0.4. The binder is a high mol. wt. material contg. alkali-solubilising gps. The photo-conductive printing plate obtd. is insensitive to preliminary exposure, and has high photo-sensitivity in a wide spectral range, e.g. including 600-2000nm range. The electrophotographic properties are not affected by prepn. or handling in day- or laboratory light. In an example, a photo-conductor layer contained an HCHO condensate of 3-bromopyrane, styrene-maleic anhydride copolymer binder and 3,6-dinitrophthalene-1,8-dicarboxylic acid anhydride.</p> |
