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Aftertreatment of Anionic Dyes on Nylon Fibres
Author(s) -
SHORE J.
Publication year - 1971
Publication title -
journal of the society of dyers and colourists
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.297
H-Index - 49
eISSN - 1478-4408
pISSN - 0037-9859
DOI - 10.1111/j.1478-4408.1971.tb02968.x
Subject(s) - tannic acid , chemistry , tannin , nuclear chemistry , dyeing , aqueous solution , acid dye , polymer chemistry , anthraquinone , organic chemistry , food science
Meeting of the Bradford Junior Section, held in Bradford Technical College, on 13 October 1969, Mr R. S. Stringer in the chair The improvement in wet fastness of anionic dyes, e.g. C.I. Acid Blue 25, on nylon fibres by aftertreatment with natural tannins is attributable mainly to modification of the substrate by the tannin, which lowers the rates of diffusion of the dye ( a ) out of the dyed fibre and ( b ) into undyed adjacent nylon. Ultraviolet spectroscopy of solutions of tannic acid (a polygalloylated glucose) has given indications of the alkaline oxidative degradation of the tannin believed to be responsible for the discoloration of backtanned dyeings. Tartar emetic increases the effectiveness of backtanning by formation of a less soluble complex with tannic acid which is more resistant to alkaline oxidation. Formic acid increases the rate of diffusion and the equilibrium uptake of tannic acid on nylon. The adsorption and diffusion behaviour of several related anthraquinone acid and disperse dyes on nylon is discussed and possible explanations are advanced of the low effectiveness of backtanning in preventing loss of dye by dyed nylon 6 and staining of undyed wool. No conclusive evidence has been obtained of interaction between C.I. Acid Blue 25 and tannic acid or tartar emetic in aqueous solution.