| abstract |
Adhesive compositions comprising (a) adhesive polymers or copolymers prepared from monomers selected from the group consisting of styrene, butadiene, acrylonitrile, ethylene, vinyl acetate acrylic acid, esters of acrylic acid, methacrylic acid and esters of methacrylic aid or combinations thereof; and (b) from 1 to 55 % an a dry weight basis of a polymeric additive comprising a low molecular weight polymer having a number average molecular weight of 20,000 or less and which comprises polymerized units of at least one ethylenically unsaturated monomer and 5 weight percent or less of a polymerized acid-containing monomer. In preferred form, the polymeric additive is polymerized in the presence of a metal chelate chain transfer agent. In certain embodiments, the polymeric additive has a midpoint Tg of at least 0 °C or greater. Further embodiments of the present invention include methods for forming the polymeric additive in situ in the adhesive composition. |