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US 4,226,752 AGranted
Emulsion process for polymer particles
AssigneeSCM Corporation
InventorsJames R. Erickson, Robert J. Seidewand
Life of this patent
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Abstract
An improved two-step process for producing large size emulsion polymer particles includes the steps of providing uniform size polymer particles in the first stage followed by a controlled second stage monomer polymerization which overcomes stability problems in large size composite emulsion polymer particle systems, and is particularly useful in coatings, adhesives, and plastics.
Claims10
An improved emulsion polymerization process for producing large particle size emulsion polymer particles wherein the improvement comprises:
- providing substantially monodispersed polymer seed particles between 500 A and 8,000 A and having a Dw/Dn of between about 1.0 and 1.1 wherein Dw is the particle weight average diameter and Dn is the particle number average diameter, said polymer seed particles being a homopolymer or copolymer containing a polymerized monomer selected from styrene, acrylate, or methacrylate;
- increasing the size of said polymer seed particles by polymerizing ethylenically unsaturated second stage monomers selected from styrene, alkyl acrylates, alkyl methacrylates, vinyl acetate, acrylic acid, and methacrylic acid onto said polymer seed particles in the presence of surfactants consisting essentially of non-ionic and anionic surfactants comprising by weight between about 30% and 98% non-ionic surfactant, said surfactant being present in the second stage processing sufficient to provide between about 105% and 1000% of theoretical polymer seed coverage to produce polymer particles containing by weight between about 5% and 95% polymerized second stage monomers.
Dependencies are inferred from the claim text.