Patents

Sherwin-Williams patents polymer dis

May 17, 2007

Patent No. U.S. 7,129,278 B2
The Sherwin-Williams Company has been granted a patent for a process for producing a water-reducible polymer dispersion useful for aqueous coating compositions. The polymer dispersion is comprised of producing a modified polymer resin having an acid value less than 30, wherein the modified polymer resin is formed by producing a low acid value polymer formed by reacting a mixture of an acidolysis reaction product of a polyalkylene terephthalate with a member of the group consisting of acid- and anhydride-functional materials, and an alcohol; wherein the low acid value polymer has an acid value of less than 20; and performing a monomer modification of the low acid value polymer with an ethylenically unsaturated monomer; subjecting the modified polymer resin to temperatures higher than the melting point of the modified polymer resin to maintain the modified polymer resin in a molten and flowable state; combining the molten modified polymer resin with water in the presence of a base at temperatures sufficient to maintain the modified polymer resin in a molten state; and forming a dispersion of the molten modified polymer resin by subjecting the modified polymer resin to high shear dispersing; and wherein a surfactant is optionally added.