Multiple use copying masks for prodn. of printing plates - comprising transparent support film bearing the image to be copied, covered with protective layer of transparent film-forming polymer contg. transparent matting agent

摘要

Masks consisting of (A) an optically transparent support film 10-500 micro-m thick, (B) an image mask layer 0.01-1 micro-m thick with optically transparent non-image regions and image regions of higher optical density obtd. by imagewise application of a 0.01 - 1 micro-m thick energy absorbing layer contg. a finely dispersed material of high optical density or an energy absorbing layer made of this, or by removing the non-image regions from this layer or by transferring the image regions to the support film (A), and (C) a 0.01 - 5 micro-m thick, non-tacky, optically transparent protective layer adhered strongly to the mask layer (B), consisting of a polymer which forms films with high tensile strength and 0.1-10 wt.% w.r.t. (C) of an optically transparent matting agent with a mean particle size of 0.1-10 micro-m. USE/ADVANTAGE - The copying masks can be used repeatedly in close contact with positive- or negative working photosensitive layers without deterioration of the mask by migration of low mol. components from the photosensitive material into the mask. This is an improvememnt over earlier systems in which a protective layer was applied over the photosensitive layer, which caused a redn. in resolution of the image during exposure. The masks are useful e.g. in the prodn. of printing plates, screen printing plates and photoresists e.g. for printed circuit