Polyester 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 XXV. Capital Equipment and Operating Cost Estimate for Dyebath Reuse Applied to Polyester Package Dyeing...

Table XXVI. Combined Cost Savings in Adaptation of Dyebath Reuse to Polyester Package Dyeing at 1.35 x 10 lb./yr. Production...

Figure 2. Dyebath reuse 50/50 cotton/polyester, high energy reactive/base-...

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

Chlorination was found (172) to be the most suitable and effective method for decolori2ing and reducing the COD of waste dyebaths containing a2o dyes. These findings have been substantiated for chlorination and biochemical purification (173). A study (174) has been done on the technical and economic feasibiUty of a chlorination dye wastewater reclamation system for treating effluent that is suitable for reuse in dyeing of polyester/cotton blends with disperse and direct dyes. 

Savings and Cost/Benefit Analysis. The bench scale experiments were successful Tn overcoming major technical problems while demonstrating that dyebath/auxiliary bath reuse is indeed feasible with reactive dyes on cotton-containing fabrics. In addition, a shortened-cycle dyeing procedure coupled with reuse for cotton/polyester blends was shown to further increase energy, mass, and time savings (Table XXX). 

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 ... 

Dyebath/auxil iary bath reuse has been demonstrated on a pilot-scale to be a feasible, economical alternative to conventional batch dyeing processes. Atmospheric disperse dyeing of nylon and polyester carpet and nylon pantyhose, and pressure disperse dyeing of polyester yarn packages have all been demonstrated as suitable candidates for plant incorporation of the reuse techniques. 

Good lot-to-lot shade correlations were also obtained with reuse of low-temperature reactive dyebaths and fixation baths on 100% cotton, and with reuse of combined high-energy reactive/disperse dyebaths and fixation baths on cotton/polyester knit fabrics. Further computer program development is required, however, before industrial shades can be matched with the reactive dye reuse system. 

---