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The Dyeing of Direct Dyes on Cotton *
Author(s) -
LEMIN D. R.,
VICKERS E. J.,
VICKERSTAFF T.
Publication year - 1946
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.1478-4408.1946.tb02405.x
Subject(s) - dyeing , controllability , salt (chemistry) , chemistry , pulp and paper industry , materials science , mathematics , composite material , organic chemistry , engineering
Summary Rate‐of‐dyeing measurements have been carried out on over fifty direct cotton dyes dyed on cotton in two liquor lengths and with three salt concentrations. The results are expressed in terms of the time of half‐dyeing and the equilibrium exhaustion. The value of the results in predicting the dyeing behaviour of binary combinations of dyes has been critically examined. It is shown that in approximately one in three cases, the course of dyeing is not that which would be predicted from the rate‐of‐dyeing measurements on the individual components, whilst the prediction of truly compatible mixtures is even less successful. From this is is concluded that rate‐of‐dyeing data on direct dyes are of little practical value. It is suggested that the rate of migration of direct dyes is of more importance than the rate of dyeing, and measurements of the migration rate and its variation with salt and dye concentrations have been made. The controllability of the dyes by salt is also highly important in practice, and the dyebath exhaustion produced by the addition of salt has been measured over a wide range of salt concentrations for all the dyes. A method of defining salt controllability is developed. On the basis of the rate of migration and salt controllability, a system of classification of the direct dyes is derived which provides some indication of the best practical method of application.