Process for the preparation of aqueous dispersions as primer for melt adhesives

摘要

Aqueous poly(meth)acrylate (I) dispersion, produced by multi-stage emulsion polymerisation, contains (I) particles comprising: (A) 50-90 wt.% alkyl methacrylate (II); (B) 5-30 wt.% alkyl acrylate of formula (III), with a glass transition temperature Tg in the -50 to -20 degrees C range; (C) 2-10 wt.% functionalised monomer, which is a glycidyl or hydroxyalkyl (meth)acrylate of formula (IV); (D) 2-10 wt.% carboxylic or polycarboxylic acid or partly esterified carboxylic acid undergoing free radical polymerisation; and (E) 0-40 wt.% other comonomer(s); CH2 = CH - CO - OR1 (III) CH2 = C(R2) - CO - OR3 (IV); R1 = 2-10 C alkyl, aryl or alkylaryl; R2 = hydrogen or methyl; and R3 = glycidyl or 2-8 C alkyl at least mono-substituted by hydroxyl. Monomers (A) to (C) and optionally (E) are copolymerised in the first stage and monomers (A), (B), (D) and optionally (E) in the second. Also claimed are: (i) the production of a (I) dispersion by this method; and (ii) heat-sealable substrates primed with (I) dispersion.