Coloration dyebath reuse

Table III. Color Uniformity in Polyester Carpet Dyeings with Dyebath Reuse...

Georgia Tech did not possess modern pressure fabric dyeing equipment at the initiation of the dyebath reuse research. Therefore, to determine the feasibility of dyebath reuse in the general area of coloration of 100% polyester under pressure with disperse dyes, research was initiated on available package yarn equipment. 

Table XXVII. Dyebath Reuse Color Difference Calculations 100% Cotton/One Low-Temperature Reactive Dye...

Table XXXII. Direct Savings in Two-Step Dyebath Reuse Coloration of Cotton/Polyester Knits Based on 3.6 x 10 Lb./Yr. Production...

An in-plant demonstration of dyebath reuse applied to coloration of nylon pantyhose has recently been completed, and the results will be published elsewhere (14). 

White B, Tincher W C, Clark J L (1998), Demonstration of automated dyebath reuse in a production facility . Text. Chem. Color, 30(12), 25-30. 

Particularly in the case of dyes with a limited degree of fixation the dyestuff content in the wasted water leads to intensively colored wastewater. As the reactive group of the unfixed dyestuff is hydrolyzed into an inactive form, a reuse is not possible. On the basis of an exhaust dyeing with 5% color depth, a liquor ratio of 1 10, and a degree of dyestuff fixation of 70-80% corresponding to 3.5-4 g/L of dye are fixed on the goods and 1.5-1 g/L of hydrolyzed dyes are released with the dyebath. 

Perkins, W.S. Walsh, W.K. Reed, I.E. Namboodri, C.G. A demonstration of reuse of spent dyebath water following color removal with ozone. Text. Chem Color. 1995, 28, 31-37. 

Dyeing of Nylon Carpet with Disperse Dyes. The objective of the first trial in the pilot-scale experiments was to dye nylon carpet to the same shade five times with reuse of the dyebath [8). The carpet was tufted from Nylon 6 face yarn with a polypropylene primary backing. Both regular nylon and cationic-dyeable yarns were used in the carpet however, the two types of yarns dyed to essentially the same color with disperse dyes. The carpet surface contained both cut pile and loops. 

To construct a model plant for incorporation of the two-step dyebath/fixation bath reuse technique to the coloration of cotton/ polyester knits, several assumptions were made ... 

The appearance of water, especially textile wastewater is systematically described in terms of its visible characteristics (Standard Methods, 1998). In this regard, the presence of color, suspended particles and turbidity is the focus of much of the testing conducted. In the case of textiles, the presence of color in wastewater is extremely important and numerical methods are normally employed to report results from making color assessments. While color in textile wastewater may arise from the presence of transition metal ions, vegetable matter and industrial plant effluents, color derived from unspent dyebaths is of primary importance. Invariably, this color is removed using a number of physical and/or chemical methods (Reife, 1993) however, methods enabling the recycle/reuse of dye-based color have been developed (Reife and Freeman, 1996). 

Hassan M. and Hawkyard C. J. (2002), Reuse of spent dyebath following decolorisation with ozone . Coloration Technology, 118,104-111. 

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