PURPOSE: To improve quick dryability at the time of production, aging stability after production, the strength of a coating film and printing resistance at the time of printing by incorporating an o-quinonediazido compd., an alkali-soluble resin and drying oil.
CONSTITUTION: Drying oil is incorporated into a positive type photo-sensitive compsn. consisting of an o-quinonediazido compd. and an alkali-soluble resin. The top of a surface-treated Al substrate is coated with a photosensitive layer contg. the resultant photosensitive compsn. and the layer is dried to obtain the objective photosensitive planographic printing plate. Since the drying oil improves quick dryability after coating with the photosensitive compsn., the photosensitive layer is satisfactorily dried, and the photosensitive planographic printing plate suppressed in the change of its performance with the lapse of time after production, that is, having high aging stability is obtd. because of the improved rapid dryability. The drying oil is, e.g. linseed oil, tung oil, perilla oil, soybean oil, sunflower oil, safflower oil, linolic acid, linolenic acid or oleic acid.
TONO KATSUHIKO
MATSUBARA SHINICHI
MITSUBISHI CHEM CORP
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