Discoloration evaluation method of paint color

摘要

PROBLEM TO BE SOLVED: To predict quickly color changing/fading property of a paint color including multiple kinds of color pigments at optional ratios without executing an actual outdoor exposure test.;SOLUTION: Color specification values (L, a, b) before and after a color changing/fading test of a paint film containing the color pigments and bright material in two or more kinds of ratios are measured to thereby operate a recurrence formula, and the operation is executed relative to all color pigments included in the paint color, and the concentrations of each color pigment in the paint color to be evaluated are applied to the recurrence formula, to thereby estimate the color specification values (Ln, an, bn), (Ln', an', bn') before and after the color changing/fading test. Then tristimulus values (Xn, Yn, Zn), (Xn', Yn', Zn') before and after the color changing/fading test are determined therefrom, and the tristimulus values are divided respectively by tristimulus values (X0, Y0, Z0) of the bright material, to thereby calculate respectively spectral transmittance substitute values (Xn/X0, Yn/Y0, Zn/Z0), (Xn'/X0, Yn'/Y0, Zn'/Z0) before and after the color changing/fading test. The substitute values are multiplied respectively by the tristimulus values (X0, Y0, Z0) of the bright material, to thereby calculate tristimulus values (Xm, Ym, Zm), (Xm', Ym', Zm') before and after the color changing/ fading test of the paint color. Then, the color specification values (Lm, am, bm), (Lm', am', bm') before and after the color changing/fading test are calculated therefrom and evaluated. Hereby, evaluation agreeing well with the evaluation by the outdoor exposure can be executed.;COPYRIGHT: (C)2002,JPO