Assessment of Some Testing Methods of Colorfastness to Light and Perspiration for Vinylsulfonyl Reactive Dyes on Cellulose Fiber and the pH Effect on their Fading by the Compound Action

Abstract

The colorfastness to light and perspiration for four vinylsulfonyl (VS) reactive dyes, C.I. Reactive Red 22, Blue 19, Black 5 and a copper-complex azo dye, on cotton fabrics was examined by seven testing methods. The pH effects on the fading by the compound action of light and sweat were also studied by these testing methods. JIS L 0888 method using with acid and alkaline perspiration could not estimate the difference in their fastness. The ATTS method with alkaline perspiration and the lactate method, followed by the Mizuno method, can estimate strictly their fastness. The differences between the fading by alkaline and acid perspiration were made by the initial period of exposure during the test fabrics were wet. By increasing the concentration of substrate in the artificial perspiration, for instance, by the lactate method, the high fastness of light and perspiration for dyes on cotton fabrics may be estimated.