| 摘要 |
2103360 9220722 PCTABS00017 The present invention relates to a method of suspension polymerization of a pressure-sensitive acrylate copolymer bead having a glass transition temperature 0f 0 ·C or less which are storage stable in addition to being extrudable at temperature below about 340 ·F (171 ·C). The method comprises making a monomer-containing premix comprising (i) about 70 to about 98 parts by weight of an acrylic acid ester monomer of non-tertiary alcohol, the alcohol having from 1 to 14 carbon atoms, with the average number of carbon atoms being about 4 to about 12, (ii) about 1 to about 10 parts of a polar monomer copolymerizable with the acrylic acid ester, and (iii) about 1 to about 40 parts vinyl acetate monomer, wherein (i), (ii), and (iii) comprise 100 parts of the monomer-containing premix, (iv) about 0.01 to about 0.5 part by weight chain transfer agent, and (v) about 0.05 to about 1.0 part by weight free-radical initiator, wherein (iv and v) are each independently base upon 100 parts by weight total monomer content and wherein about 0.5 to about 30 parts by weight modifier moiety based upon 100 parts by weight total monomer content is present in one or more of the following: said monomer-containing premix, said water phase; the oil-in-water suspension; the aqueous suspension of polymer beads after the exotherm of the polymerization has been reached. The monomer-containing premix is then combined with a water phase containing a sufficient amount of suspending agent to form a suspension. The suspension is concurrently agitated and polymerization of the monomer is permitted until polymer beads are formed. The polymer beads are then collected. The invention also relates to the polymer beads themselves and adhesives prepared therefrom.
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