U.S. 7,867,555 B2
Valspar Sourcing Inc. has been granted a patent for a method comprised of extruding a base powder mixture to form a base powder with a particle size of 10 to 300 microns, wherein the base powder mixture comprises a carboxyl-functional polyester resin curable with an epoxide-functional compound; mixing the base powder with at least one stable colorant dispersion below approximately 40° C to form a colored mixture in which particles of the base powder are coated with a colorant and there is a minimal change in the particle size of the base powder particles, wherein the stable colorant dispersion consists of at least one of a pigment and a dye in a liquid carrier, wherein the liquid carrier is selected from water, organic solvents and combinations thereof, and wherein the liquid carrier does not cause melting or softening of the base powder, and wherein the pigment is selected from organic pigments with a median particle size of less than 0.3 microns, titanium dioxide pigments with a median particle size of 0.3 to 0.5 microns, iron oxide pigments with a median particle size of 0.2 to 0.6 microns, carbon black pigments with a median particle size of approximately 0.07 microns, and phthalocyanine blue pigments with a median particle size of approximately 0.05 microns; and treating the colored mixture at temperatures below the softening point of the base powder to form a free flowing powder.
Valspar patents dispersion-coated powder coloring system
Published January 19, 2012
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