Patent No. U.S. 7,479,525 B2
E.I. Du Pont De Nemours and Company has been granted a patent for an isocyanate adduct useful as an isocyanate crosslinking agent in solventborne coating compositions, wherein the isocyanate adduct is a product obtained by the reaction of a gelled acrylic polymer with an excess of polyisocyanate compounds. The gelled acrylic polymer is dispersed in an organic liquid carrier, and consists essentially of a crosslinked core comprised of polymerized ethylenically unsaturated monomers, wherein the core is not soluble in the organic liquid carrier, and linear stabilizer polymeric components chemically grafted to the core, wherein the linear stabilizer components have weight average molecular weights in the range of 500-20,000 as determined by GPC (gel permeation chromatography) using polystyrene as standard, wherein the stabilizer components comprise polymerized ethylenically unsaturated monomers; the stabilizer components are soluble in the organic liquid carrier; the core, the stabilizer polymeric components or both contain isocyanate-reactive hydroxy and/or secondary amine functional groups attached thereto; and the excess of polyisocyanate compounds are present in an amount so that the ratio of NCO to OH/NH groups ranges from 5:1 to 50:1.
COATING CONTAINING ISOCYANATE-FUNCTIONAL DISPERSED POLYMERS
Published January 11, 2010
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