| 摘要 |
PURPOSE:To obtain the printing plate which is long in print-resisting life, is thick, has less variations in thickness and is of high resolving power by coating water- soluble or water dispersion type polyvinyl alcohol composition on the surface of an ultraviolet polymerization type photosensitive resin layer and exposing the same to ultraviolet rays. CONSTITUTION:An ultraviolet polymerization type photosensitive resin layer is formed by coating or affixing on a screen cloth. The water-soluble or water dispersion type composition of polyvinyl alcohol (degree of saponification 80% or over, degrees of polymerization 500 to 2000) or its copolymer (vinyl alcohol units 60 mole% or over) is coated on both surfaces of said resin layer followed by drying. A positive film is contacted on this and is exposed. To this follow removing the positive film, removing the unexposed parts, rinsing and drying and further re- radiating thereby obtaining the printed plate. Since the non-permeability of oxygen of the polyvinyl alcohol film is high, polymerization is not impaired and the thick film of a long print-resisting life is readily obtained. |
