Sulfonic acid group-containing polyurethane and a photosensitive resin composition containing the same

Abstract

A sulfonic acid group-containing polyurethane produced from a sulfonic acid group-containing polyamide diol and/or a sulfonic acid group containing polyester diol, a dihydroxyhydrocarbon having a specific molecular weight and a diisocyanate. This polyurethane has not only high hydrophilicity but also excellent mechanical strength, excellent heat resistance, low permanent tensile set and low hardness, which are required for the base polymer for a photosensitive resin composition to be used for producing a flexographic printing plate. Further, a photosensitive resin composition containing such a sulfonic acid group-containing polyurethane has excellent photosensitivity and in addition, has excellent properties such that after the photosensitive resin composition has been exposed to actinic rays through an image-bearing transparency, the development of the exposed composition can be performed with water or an aqueous alkali solution. From this photosensitive resin composition, a flexographic printing plate having excellent printing resistance, ink resistance and mechanical properties can be obtained.

Dependencies are inferred from the claim text.