Copolymers for pressure-sensitive adhesives based on acrylic esters, (meth)acrylamide vinyl acetate and ethylene

A process for the production of a copolymerizate containing:

• (a) from 10% to 30% by weight of ethylene monomeric units,
• (b) from 29% to 69% by weight of monomeric units of an acrylic acid ester of an alkanol having from 4 to 12 carbon atoms,
• (c) from 20% to 55% by weight of vinyl acetate monomeric units,
• (d) from 0.2% to 8% by weight of monomeric units having the formula:
• ##STR7## wherein R' is a member selected from the group consisting of hydrogen and methyl, and R" is hydrogen, and
• (e) from 0 to 12% by weight of other olefinically-unsaturated monomeric units copolymerizable with ethylene, vinyl acetate and alkyl acrylate and monomers as described in (d), said copolymerizate having a glass transition temperature of from -20.degree. C. to -60.degree. C. and a K-value according to Fikentscher, measured in tetrahydrofuran, of from 50 to 180,
• consisting of dispersing the monomeric units of components (b), (c), (d) and (e) in amounts sufficient to give the desired ratio of monomer units in the final copolymerizate in water in the presence of from 1.5% to 8% by weight, based on the monomers, of dispersants selected from the group consisting of emulsifiers, protective colloids, and mixtures thereof, polymerizing said dispersion in the presence of free-radical initiators under an ethylene pressure of from 20 to 120 bar and at a temperature of from 10.degree. to 90.degree. C. for a time sufficient to complete the polymerization and recovering said copolymerizate.