Preparation of water-soluble binder compositions for heat-sealable coatings for aluminium foils, and heat sealing lacquers containing these binders

摘要

The invention relates to a process for preparing water-thinnable binder compositions based on thermoplastic copolymers for heat-sealable coatings for aluminium foils, and to heat-sealing lacquers formulated with these binders for the packaging industry. The product properties necessary for practical application are achieved in a three-stage process in which a copolymer which consists essentially of alkyl (meth)acrylate and contains minor amounts of glycidyl (meth)acrylate is reacted with an equivalent amount of (meth)acrylic acid and then short side chains of (meth)acrylate and (meth)acrylic acid are polymerised onto it. The water-thinnable heat-sealing lacquers formulated therefrom contain from 20 to 30% by weight of polymer, from 15 to 20% by weight of organic solvent and from 50 to 65% by weight of water.