Photosensitive composition

摘要

A photosensitive composition capable of producing a photosensitive lithographic printing plate having excellent developing property and press life in direct lithoprinting even if stored in an atmosphere having high temperature and humidity. The photosensitive composition comprising a diazo resin (a) wherein a counter anion is an inorganic acid anion or an aliphatic organic acid anion having 3 or less carbon atoms; a diazo resin (b) wherein a counter anion is an aliphatic or aromatic organic acid anion having 6 or more carbon atoms; and a polyurethane resin which is a reaction product of an isocyanate comprising 40 to 90 mol% of a diisocyanate represented by the general formula (I) defined hereinabove based on the amount of total isocyanate components with an alcohol comprising 30 to 90 mol% of a diol represented by the general formula (II) defined hereinaove based on the amount of total alcohol components.