Interleaf paper for photosensitive printing plate material

Abstract

The interleaf paper for covering a photosensitive printing plate material which is coated with a water-soluble oxidization preventing layer, is characterized in that the interleaf paper has air permeability of between about 15 seconds and about 300 seconds. If the photosensitive printing plate material is covered with the interleaf paper, it is possible to release the interleaf paper in the automatic interleaf paper releasing apparatus and stabilize the sensitivity of the photosensitive printing plate material in a short period of time.

1 . Interleaf paper for a photosensitive printing plate material which is coated with a water-soluble oxidization preventing layer, wherein said interleaf paper has air permeability of between about 15 seconds and about 300 seconds.  
     
     
         2 . The interleaf paper for the photosensitive printing plate material as defined in  claim 1 , wherein said interleaf paper of which weight, density, flatness and moisture are about 38 g/m 2 , about 0.8 g/cm 3 , about 60 seconds and about 6.0%, respectively, is produced by beating bleached craft pulp, dissolving the pulp in water to make stuff of density of about 4%, adding about 0.4 wt % of a synthetic size agent to the stuff, adding aluminum sulfate to the stuff until pH of the stuff reaches about 5.0, making paper from the stuff, and applying about 3.0 wt % of paper strength additive consisting essentially of starch on the paper.  
     
     
         3 . The interleaf paper for the photosensitive printing plate material as defined in  claim 2 , wherein the surface of said interleaf paper is coated with about 2 g/m 2  of polyvinyl alcohol.