Patent No. U.S. 7,727,702 B2
Ciba Specialty Chemicals Corp. has been granted a patent for a method of irreversibly coloring a coating composition containing a color former comprised of the steps of a) providing a coating composition that contains a thermosetting resin with the proviso that the coating composition contains no developer nor any additive which may function as developer; b) mixing the coating composition with the color former whereby no color is formed; c) applying the colorless composition obtained in step b) to a substrate; d) in case of a thermosetting resin other than an alkyd resin curing the resin between 100˚ and 300° C whereby no color is formed, and in case of alkyd resin drying of the resin at room temperature, whereby no color is formed; e) exposure to UV or high energy radiation below 400nm whereby the color is formed.