| abstract |
A method for producing polymers which are anhydride modifications of polymers containing hydroxyl groups, such as polyvinyl acetal polymers. Such modified polymers are useful as binders for photosensitive compositions used to prepare photographic elements such as lithographic printing plates, color proofing films and photoresists. The binder is the reaction product of an intramolecular anhydride of an organic polycarboxylic acid with a polymer containing hydroxyl groups, and which does not contain other functional groups which are capable of reaction with acid anhydrides. The reaction is conducted in a solvent composition free of hydroxyl containing solvents such as methyl ethyl ketone and ethylene glycol monomethyl ether. |