| 摘要 |
PURPOSE:To obtain a photosensitive composition suitable for manufacturing a lithographic plate with superior resistance to processing chemicals and superior printing resistance by adding a specified polyhydroxyphenyl resin to a photosensitive composition contg. an o-quinone diazide compound. CONSTITUTION:A coating soln. contg. >=1 kind of polyphenyl resin represented by the formula (where R1 is 1-8C alkyl, R2 is H, halogen, 1-4C alkyl or alkoxy, and each of R3 and R4 is H, 1-4C alkyl or phenyl) and an o-quinone diazide compound is applied to an anodically oxidized Al plate or the like to obtain a photosensitive lithographic plate. This plate is contact-exposed through a transparent original and developed with an alkaline aqueous soln. of sodium metasilicate or the like. Thus, the plate is developed quickly to give an offset printing plate with superior sensitivity and superior resistance to processing chemicals. |
