The invention provides a near-infrared absorbing material showing a high sensitivity to a YAG laser having an emission wavelength of 900∼1100 nm as well as a high photothermal conversion efficiency, an original plate for direct printing plate making which utilizes the near-infrared absorbing material, and a novel polymethine compound represented by the following general formula (1), of which the above near-infrared absorbing material is comprised.
(wherein R1 and R3 each independently represents an unsubstituted or substituted alkyl group, a cycloalkyl group of 5~7 carbon atoms or an unsubstituted or substituted aryl group; R2 and R4 each independently represents an unsubstituted or substituted alkyl group or an unsubstituted or substituted aryl group; R5 and R6 each independently represents a hydrogen atom, an unsubstituted or substituted alkyl group or an unsubstituted or substituted alkoxy group; L represents an unsubstituted or substituted alkylene group of 2∼4 carbon atoms which is necessary for formation of a cyclic structure; X represents a hydrogen atom, a halogen atom or a substituted amino group; Z represents a charge-neutralizing ion)
本发明提供了一种对发射波长为900∼1100nm的YAG激光具有高灵敏度和高光热转换效率的近红外吸收材料,一种利用该近红外吸收材料的直接印刷制版用原版,以及一种由以下通式(1)表示的新型聚
甲基化合物,上述近红外吸收材料由该化合物组成。
(其中 R1 和 R3 各自独立地代表未取代或取代的烷基、5~7 个
碳原子的
环烷基或未取代或取代的芳基;R2 和 R4 各自独立地代表未取代或取代的烷基或未取代或取代的芳基;R5 和 R6 各自独立地代表
氢原子、未取代或取代的烷基或未取代或取代的烷
氧基; L 代表 2∼4 个
碳原子的未取代或取代的亚烷基,这是形成环状结构所必需的; X 代表
氢原子、卤素原子或取代的
氨基; Z 代表电荷中和离子)