Sodium Borohydride in Vat Dyeing

Abstract

A suitable redox titration procedure has been standardized and the effect of sodium borohydride in various vat dyebaths has been studied. An analysis of the redox curve gives valuable data on the stability of the reducing system, leucopotential of the dye, and over-all stability of the dyebaths. It is shown that sodium borohydride does not improve the stability of the dyebath against oxidation. In certain systems, it even shows adverse effects. Results indicated that sodium boro hydride cannot be a total or partial substitute for sodium hydrosulfite in current vat dyeing practice. This finding has been verified by hank-dyeing. In vatting and dyeing, the specificity of a reducing agent appears to be more important than its reduction potential.