| 摘要 |
PURPOSE:To obtain a printing plate superior in resistances to chemicals and ball pen writing by incorporating polyphenol polycondensate naphthoquinonediazidosulfonate specified in characteristics and a cresol novolak resin in a photosensitive layer. CONSTITUTION:The photosensitive layer formed on the grained surface of an anodized aluminum plate contains the ester of the polycondensate of the polyphenol with aldehyde or ketone, with naphthoquinonediazidosulfonic acid having a number average molecular weight of 5.00X10<2>-3.60X10<3>, and a weight average molecular weight of 2.00X10<3>-5.80X10<3>, and an esterification rate of 10-25%, and the polycondensate resin of a mixture of m-cresol and p-cresol in a weight ratio 55:45-99:1 and an aldehyde or a ketone, thus permitting the obtained printing plate to be improved in resistances to chemicals and ball pen writing, erasability of sticking traces, and development latitude. |
