Processes for Cellulose 2.5 Acetate

For the theoretical aspects of dyeing CA and CT with disperse dyes see Section 4.12.1. CA is dyed by the exhaustion method in the presence of a nonionic or anionic dispersing and leveling agent in a weakly acidic bath (pH 5-6). A series of less wetfast disperse dyes are taken up by acetate at temperatures as low as 50-60 °C. For this reason, the process must be started at a correspondingly low temperature to obtain level dyeings. Dyeing is normally done at 80-85 °C. Dyes 

Piece goods made of CA are usually dyed in a jigger, less often in a star frame or winch beck, with gentle material guidance. The piece beam is suitable for warp materials. Yam was previously dyed in hanks. Since suitable winding machines are available, CA can also be dyed on cylindrical cheeses. Woven CA fabrics are occasionally dyed semicontinuously in a pad roll system at 80-90 °C. Dyeing auxiliaries are subsequently washed out. 

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