US Patent 7309550 Photosensitive composition with low yellowing under UV-light and sunlight exposure

This disclosure relates to a photosensitive composition useful in preparing water-developable, relief printing plates and other photosensitive articles. The compositions comprise an unsaturated polyurethane pre-polymer, which is the reaction product of at least one polyether diol, at least one aliphatic diisocyanate, at least one hydroxyl-functionalized mono-, di- and tri-(meth)acrylate, and a particular photoinitiator. The resulting photosensitive resin compositions have reduced rates and levels of yellowing if subjected to additional UV-light or sunlight after processing.