Developments in the Application of Dyes to Cellulose Acetate Rayon

Abstract

The disperse dyes are likely to remain the principal dyes for acetate rayon, particularly for piece dyeing. The “duosol” dyes are unlikely to supersede them for general purposes, but are likely to increase in importance with expanding use of acetate staple fibre. The azoic dyes, applied by the “concurrent” method, supplement the above groups for specific shade requirements such as fiery scarlets and deep rich wines, and in addition are fast to wet processing. Solvent dyeing as an economic step has achieved some measure of success, chiefly in America, but the application of vat dyes by such techniques still remains a problem which is very much for the expert. For printing acetate rayon goods the disperse dyes, though much used, suffer from inherent processing and fastness defects, and it is desirable to replace them by the “duosol” and acid dyes for normal requirements. Selected vat dyes may also be applied very satisfactorily. The use of swelling agents, e.g. the thiocyanates and water‐soluble polar solvents such as ethyl lactate, offers great scope for prints of improved beauty and fastness, and in certain cases permits elimination of the steaming operation.