POSITIVE WORKING THERMAL IMAGING ASSEMBLY, METHOD FOR THE MANUFACTURE THEREOF AND LITHOGRAPHIC PRINTING PLATE

摘要

The invention relates to Positive working thermal imaging assembly comprising: A) a substrate; and B) a thermally sensitive imaging element of a composite layer structure comprising: a layer on the substrate of a polymeric material soluble in aqueous alkali solution, optionally containing compounds that absorb and convert light to heat and/or a coloured dye or pigment; said first layer being converted at its surface by treatment with solutions at elevated temperatures that contain an active compound or compounds capable of rendering said first polymeric material insoluble to aqueous alkali developer at the point of contact; said layer being oleophilic; The assembly is useful as off-set lithographic printing plates, for color proofing films and photoresist. The invention also refers to the process for making such assembly and products formed therefrom.