A presensitized plate for use in making a lithographic printing plate comprises a substrate provided thereon with a light-sensitive layer formed from a light-sensitive composition comprising a diazonium polymeric compound having two kinds of specific repeating units and a lipophilic polymeric compound having an acid value of not less than 20 and less than 250. The presensitized plate can provide a lithographic printing plate having excellent printing durability since the diazonium compound used has a high molecular weight. Moreover, since the diazonium compound has alkali-soluble groups and the lipophilic compound having an acid value of not less than 20 and less than 250 and easily soluble in an alkaline water is used as a binder, the presensitized plate has good developability and can provide a lithographic printing plate free of background contamination.
一种用于制作平版印刷板的预敏板,包括一个基板,基板上有一个感光层,感光层由感光组合物形成,感光组合物包括具有两种特定重复单元的重氮高分子化合物和酸值不小于 20 且小于 250 的亲脂高分子化合物。由于所使用的重氮化合物具有较高的分子量,因此预感光版材可以提供具有出色印刷耐久性的平版印刷版材。此外,由于重氮化合物具有碱溶性基团,而亲脂性化合物的酸值不小于 20 且小于 250,并且易溶于碱
水作为粘合剂,因此预敏印版具有良好的显影性,可以提供无背景污染的平版印刷版。