Thermally imageable lithographic printing plate precursors and heat-sensitive compositions for use in these printing plate precursors are disclosed. The compositions contain an aqueous developer soluble polymer, such as a phenolic resin; a compound that reduces the aqueous developer solubility of the polymer; and optionally, and infrared absorber. Examples of compounds that reduce the aqueous developer solubility of the polymer are those that contain at least one quarternized nitrogen atom, such as quinolinium compounds, benzothiazolium compounds, pyridinium compounds, and imidazoline compounds. On thermal imaging, the irradiated areas become more soluble in the aqueous developer and can be removed to form a positive image.
本发明公开了热成像平版印刷板原版和用于这些印刷板原版的热敏组合物。这些组合物包含
水性显影剂可溶聚合物,如
酚醛
树脂;降低聚合物
水性显影剂溶解度的化合物;以及可选的红外线吸收剂。降低聚合物
水溶性显影剂溶解度的化合物包括至少含有一个四价氮原子的化合物,例如
喹啉化合物、
苯并噻唑化合物、
吡啶化合物和
咪唑啉化合物。在热成像过程中,辐照区域在
水性显影液中的溶解度会增加,并可被去除以形成正像。