Color Matching and Utilization of Teegafix High Efficiency Fiber Reactive Dyes in a Production Setting

Abstract

Even with all the new types of synthetics, nanofibers, and moisture management technologies, cotton fiber remains one of the top, if not the top textile substrate in the global fiber market. Since the development of fiber reactive dyes by ICI in the 1950's, they have been the colorant of choice for cotton fabrics, as they are unmatched in their spectrum of possible colors and fastness properties. However, their use is accompanied by high levels of unfixed (hydrolyzed) dye and large amounts of salt. The unfixed dye must be removed, requiring large amounts of wash water that becomes aesthetically and sometimes chemically polluting. The large amount of salt causes aquatic toxicity to biological systems. Advancements in reactive dye chemistry led to bifunctional and hetero bifunctional dyes that have helped improve the fixation and efficiency of reactive dyes. Recently, researchers at North Carolina State University examined structural modifications of existing reactive dyes and optimized a two-step process that yields reactive dyes having high affinity, high exhaustion, and high fixation. Starting with commercial Procion® MX dichlorotriazine (DCT) reactive dyes, new dyes were produced by reactions involving two equivalents of cysteamine followed by the addition of two equivalents of cyanuric chloride. This sequence afforded bis-DCT reactive dyes from Procion® Yellow MX-3R (CI Reactive Orange 86), Procion® Red MX-8B (CI Reactive Red 11), and Procion® Blue MX-2G (CI Reactive Blue 109) that have been given the Teegafix designation. This research focuses on the ability of Teegafix reactive dyes to match certain commercial color standards and to be applied in a production mill. A model predicting the reductions of dye and salt compared to the parent Procion® MX dyes is shown. Exhaustion and fixation levels from sample lots are calculated for dye formulations containing Teegafix Yellow and Blue dyes, and the unmodified red dye. Repeatability, levelness, and color evaluations are presented including, waterfastness, washfastness, crockfastness, and lightfastness of dyed and finished lots. Dye syntheses were conducted to try to produce an improved form of the Teegafix Red dye, which gives unexpectedly dull shades. Also, syntheses were conducted using Procion® Brilliant Red H-EGXL, a monochlorotriazine (MCT), where the same modification converted the parent MCT to a DCT dye. The results of commercial-scale (60-lb lots) color matching studies showed that key industrial shades could be matched using Teegafix dyes and when employed in dye formulations in place of the corresponding commercial DCT dyes, the commercial dyes required ˜60% more dye and the substitution did not adversely affect fastness properties.

Description

Keywords

dyeing, cotton, Teegafix, high efficiency fiber reactive dyes

Citation

Degree

MS

Discipline

Textile Chemistry

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