| abstract |
The positive-type photosensitive composition according to the present invention contains a novolak resin (A), an alkali-soluble resin (B) selected from the group consisting of resins prepared by addition polymerization of a vinyl compound and condensation polymers such as imide, amide, urethane, urea, ester, and resol resins, an infrared absorbing agent (C), and a sulfonium salt (D). The positive-type photosensitive composition is superior in sensitivity, greater in layer strength, and readily dissociates by infrared ray exposure, and thus is useful as the recording layer for positive-type planographic printing plate precursors. |