Coatings World - September 2009

Patents Update
PPG patents fluorescent colorants

Patent No. U.S. 7,384,694 B2

PPG Industries has been granted a patent for a multi-layer coating applied to a substrate wherein the coating reflects colored light and is comprised of an upper layer comprised of a resinous binder and colorants which emit fluorescent light when exposed to visible light; the colorants being selected from dyes and pigments that will not scatter light that mask fluorescent light; the colorants being present in the upper layer in amounts of 0.001 to 50 weight percent; and a lower layer comprising a resinous binder and light-absorbing particles, wherein the coating composition exposed to a first light level exhibits a first colored appear-

ance that is dominated by absorbance of light by both of the colorants and the light-absorbing particles and wherein the coating composition exposed to a second light level of higher intensity than the first light level exhibits a second colored appearance dominated by fluorescent light emitted by the colorants, wherein the lower layer has a color value L* less than 40.

ROHM AND HAAS PATENTS COATING COMPOSITION Patent No. U.S. 7,417,086 B2 `Rohm and Haas Company has received a patent for a method of making an aqueous composition, suitable when dry as a coating, comprised of providing at

least one aqueous polymer that has a glass transition temperature from -80° C to 110° C, wherein the aqueous polymer is made by aqueous emulsion polymerization of a monomer mixture that excludes all dienes and that comprises 1% to 99% acrylate monomers, by weight based on the total weight of all monomers; adding to the aqueous polymer at least 10 ppm of at least one coordinating agent, by weight based on the dry weight of the at least one polymer, and raising the pH of the aqueous polymer from 7 or less to above 7, wherein the aqueous composition contains 0 to 100 ppm ammonia compound, by weight based on the dry weight of the at least one polymer. CW