A method for the preparation of radiation-curable polyester acrylate - binders

摘要

Prepn. of polyesters (polyester acrylates) from polycarboxylic acids, opt. hydroxycarboxylic acids, polyhydroxy cpds., and acrylic acids comprises (a) azeotropically esterifying in a mixt. of one or more di- or higher functional carboxylic acids, partially or totally in anhydride form, one or more di- or higher functional hydroxy cpds. and acrylic acid, in a ratio of COOH(total):OH:acrylic acid or 1:0.9-1.5:0.2-0.7 with the addn. of solvent (mixt.) as drug aid, a crosslinking catalyst and a polymerisation inhibitor or a combination of several polymerisation inhibitors under an air inlet at 60-150 deg.C to a constant acid number; and (b reacting the prod. to an acid number of less than 10, pref. less than 5, after adding a carboxy-epoxy catalyst and a mono- or higher functional epoxy cpd. (mixt.) at 50-150 deg.C and the solvent (mixt.) is distilled off. USE/ADVANTAGE - The prepn. is simpler, the time taken is reduced, the prod. has high acryloyl content or high functionality at relatively low viscosity. UV irradiation gives hard adhesion-free and highly crosslinked films. The polyester acrylates are useful as film-formers for UV and electron hardenable coating materials.yl