SIMULTANEOUS EFFECT OF LIGHT AND PERSPIRATION ON FADING OF VINYLSULFONYL REACTIVE DYES ON CELLULOSE

The simultaneous effect of light and perspiration on the fading of 6 vinylsulfonyl reactive dyes, C. I. Reactive Red 22, Blue 19, Black 5, an aminopyrazolinyl azo dye (Yellow), a copper complex azo dye (Blue-Cu) and a copper phthalocyanine dye (Cu-Pc), on cellulose fabrics was investigated by the use of the ‘A method’ of JIS L 0888 with the artificial acidic perspiration of the ATTS (Association for Textile Technical Study) and JIS L 0848. By removing each component from the ATTS artificial perspiration, these dyes were classified into two groups depending on the fading behavior by the component, of which, with an exception, lactic acid gave the largest effect followed by histidine and glucose in decreasing order. Aspartic and panthotenic acids gave a suppression effect with an exception. The ATTS artificial perspiration and lactic acid gave the severe fading for C. I. Reactive Black 5, while the artificial acidic perspiration of JIS L 0848 gave a weak one. The dyed fabrics after soaking in aqueous solutions containing each one component of lactic acid, histidine, glucose, panthotenic acid and aspartic acid showed so complex fading behavior that the simple comparison among the effect of each component could not be made. The effect of component on the fading of VS dyes were appeared in the initial fading in which excess amount of aqueous solution on fabrics took a part and in the subsequent fading under the conditions of 100% RH after the evaporation of excess water. Water gave the accerelated fading in the decreasing order: Red 22>Yellow>Black 5>Blue-Cu>Cu-Pc>Blue 19. Panthotenic acid gave an accerelated effect on the fading when used singly, but a supression effect in a mixture of lactic acid. Cu-Pc was photoreduced during the exposure after soaking in the artificial perspiration, which was shown by the color of leuco compound formed on fabrics and recolored after the oxidation in water or in air.