Method for producing esters from polyalcohols

摘要

A process for the production of a cross-linked hydrogel comprises crosslinking of monoethylenically unsaturated compounds with an ester formed by reaction of a polyalcohol with at least one ethylenically unsaturated carboxylic acid in the presence of at least one esterification catalyst and at least one polymerization inhibitor. A process for the production of a cross-linked hydrogel (I) comprises: (a) reaction of a polyalcohol (A1) with at least one ethylenically unsaturated carboxylic acid (A2) in the presence of at least one esterification catalyst (A3) and at least one polymerization inhibitor (A4) and optionally a solvent (A5) that forms an azetrope with water to form an ester (A6); (b) optionally removal of at least some of the water from the reaction mixture after or during step (A); (c) optionally neutralization of the reaction mixture; (d) optionally removing the solvent (A5) if present by distillation and/or stripping using an inert gas; (e) polymerization of the resulting reaction mixture optionally with additional monoethylenically unsaturated compounds (N) as well as optionally at least one further copolymerizable hydrophilic monomer (M) in the presence of a radical initiator (K) and optionally at least one graft base (L); (f) optionally post-crosslinking of the reaction mixture; (g) drying of the reaction mixture; (h) optionally grinding the reaction mixture. Independent claims are included for: (1) the polymer resulting from the process and; (2) the cross-linked hydrogel.