Patent ID: 9200084
Filing Date: 2015-12-01
Classification: C08B

Abstract:
1. A method for the preparation of a particulate reversibly-crosslinked polymeric material comprising: treating a particulate water-soluble hydroxyl-functional polymer selected from hydroxyethyl celluloses and hydroxypropyl celluloses in a liquid phase comprising a solvent mixture in that the hydroxyl-functional polymer is insoluble comprising an organic solvent and water, the amount of water being 2 to 50 weight %, based on the total weight of the solvent mixture; and a tetracarboxylic acid dianhydride; selected from group consisting of 1,2,3,4-butanetetracarboxylic acid dianhydride; ethylenediaminetetraacetic acid dianhydride; and 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride; to form a particulate reversibly-crosslinked polymeric material.