Influences of Introduced Hydrophobic Groups and Cross Linkages on the Fastness to Washing of Rayon Fabrics Dyeable With Cationic Dyes

Abstract

In a previous study it was shown that the rayon fabric in which acid and hydrophobic groups were introduced, indicates good dyeing property for cationic dyes and good colour fastness to washing, but the mechanism of the fastness has not been clarified.In the present study an attempt was made to introduce the acid and hydrophobic groups into the rayon fabric with a reaction which differs from that in the previous study. The influences on the fastness of the quantities, and the acidity or the hydrophobic character, of acid and hydrophobic groups were also discussed.Results obtained are as follows:(1) Although an acid and a hydrophobic group were introduced by carboxy methylation and esterification respectively, good fastness to washing was also obtained like in previous study.(2) The intensity of acidity of acid groups coexisting with hydrophobic groups gives no influences on the fastness.(3) The sequence of acid or hydrophobic group introduction into the rayon fabric gives no influences on the fastness.(4) The fastness seems to correlate to the degree of swelling of the fabric and also depends on the interaction between dyes and fiber as well as on the intermolecular crosslinkage.

Equilibrium sorption of crystal violet by carboxymethylated cellulose with low degree of substitution

“…It is interesting to mention that according to Sone et al [14,15] sorption isotherms of a cationic dye on partially carboxymethylated viscose rayon and on an untreated one as well, were Langmuir-type and the affinities of the dye to the modified fibers were the same as those to the untreated one. The heat of dyeing and the entropy differed not so much from the values of the untreated fibers.…”