The preparation, properties and dyeing behaviour of differential-dyeing cellulose

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Clipson, J.A., 1987. The preparation, properties and dyeing behaviour of differential-dyeing cellulose. PhD, Nottingham Trent University.

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Abstract

Treatment of cotton fibre or yarn with colourless reactive dye analogues containing quaternary ammonium groups introduced positive sites into cotton which enhanced its affinity for anionic dyes. Yarns pre-treated with such cationic reagents, or spun from treated fibres, showed preferential dye uptake when dyed together with untreated cotton.

Since the degree of differential dye uptake depended on the level of pre-treatment a range of yarns of differing dye capacities could be produced enabling a variety of tone-on-tone effects to be obtained.

Treated yarns showed differential-dyeing behavior with all the normal cellulosic dyes and also with acid dyes, which showed a 1:1 stoichiometry between the sulphonic acid groups on the dye and cationic sites in the fibre. Some control could be exercised over the high diffusion rates of dyes by the selection of suitable counter-ions or use of anionic levelling agents.

The contrast between treated and untreated yarns generally increased with decreasing concentration of added electrolyte, increasing temperature and liquor ratio and decreasing affinity of the dye for untreated cellulose. Mercerising, and bleaching of treated cotton with sodium hypochlorite, had no effect on its dyeability.

Treatment of cotton with cationic reagents considerably improved the wash fastness properties of direct dyes, although those of reactive dyes were slightly reduced. Light fastness ratings on treated cotton were slightly lowered, particularly with reactive dyes.

Cotton fibre and yarn has also been treated with analogous reactive anionic reagents to produce basic-dyeable cotton and combinations of anionic and cationic yarns cross-dyed two colours from one dyebath containing anionic and cationic dyes in a one-step process, with minimal cross-staining.

Both cationic and anionic differential-dyeing varieties of cellulose triacetate and viscose rayon have also been prepared from celluloses pre-treated with cationic and anionic reagents respectively. Such reagents have also found application in the printing of cotton fabrics.

Item Type:

Thesis

Creators:

Clipson, J.A.

Date:

1987

ISBN:

9781369325140

Identifiers: