| 摘要 |
PROBLEM TO BE SOLVED: To obtain a photopolymerizable planographic printing plate having stable sensitivity and causing no residual color and no residual film by specifying the water content of an overcoat layer. SOLUTION: Then a photopolymerizable planographic printing plate with an overcoat layer based on a water-soluble polymer is produced, the water content of the overcoat layer is adjusted to 4-7%, preferably 4.5-6%. The water- soluble polymer is typified by a water-soluble vinyl polymer, in particular polyvinyl alcohol, its partial ester or ether or polyvinyl acetal. Polyvinylpyrrolidone, gelatin or gum arabic is also useful and two or more such polymers may be used. The polyvinyl alcohol preferably has 71-100% hydrolysis rate and a polymerization degree of 300-2,400. The dry coating weight of the overcoat layer is usually 0.5-10 g/m2. |
