Dyes and Chemicals

Similar strict requirements for accuracy apply to chemicals and dyeing auxiliaries. Most auxiliaries show a distinct affinity for fibers or dyes. Their amount must therefore be strictly calculated and dispensed to the requirements of each individual dyeing. Today metering devices exist in the dyehouse which permit the dispensing of widely differing volumes and weights. 

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E. R. Trotman, Dyeing and Chemical Technology of Textile Fibres, Wiley-Interscience, New York, 1984, pp. 193—200. 

Dispersion Stability of Disperse Dyes at High Temperature. A disperse dye dyebath is treated under the desired test conditions at 130°C in a special apparatus (Gaston County Lab Dye and Chemical Tester) and filtered through cotton and polyester filters. The filter with the heaviest residue is then compared with a series of standard photographs of standard performance and rated equal to the one it most resembles (1 poor, 5 excellent). 

Dyes and chemicals m textile finishing an introduction Non-dyestuff chemicals safe handling m textile finishing Dyestuffs safe handling m textile finishing... 

Hazards from dyes and chemicals in textile finishing a brief guide for employees Reactive dyes safe handling in textile finishing... 

Haber was born in the city of Breslau, Silesia, then part of Germany, on December 9, 1868. As the gateway to German culture for many Eastern European Jews, Breslau bred many a superpatriot, Haber included. Fritz s mother died within days of his birth. His father, a civic leader and successful trader of dyes and chemicals, rejected the child and left his upbringing to various relatives. As a young man, Fritz wanted to become a chemist, but his father insisted that he join the family business. Only after Haber achieved worldwide fame did the two reconcile. 

Aromatic amines are of considerable importance commercially. The simplest aromatic amine, aniline. ChH5NH2, is used in the production of various dyes and chemicals for color photography. 

It should be noted that automatic dosing and monitoring of dyes and chemicals can be used generally and is not restricted to pH control. 

Tincher W, Weinberg M, Stephens S (1988) Electrochemical removal of dyes and chemicals from textile wastewater, AATCC Annual Technical Conf, Knoxville, Tenn, through Ref [312]... 

In the debate about the toxic effects of dyes and chemicals, there is no doubt that carcinogenic effects are perceived by the general public as the most threatening. Chemicals remain a focus for this concern in spite of the weight of evidence that they make only a minor contribution to the incidence of cancer [60,67,83]. The generally accepted estimate of cancer causation, based on mortality statistics, indicates that only 4% of all cancer deaths are attributable to occupational exposure. Another 2% are considered to arise from environmental causes and 1% from other forms of exposure to industrial products. 

Aniline is a purple dye that has the distinction of being the first synthetic dye ever made. It was developed in Germany at the end of the 19th century and its manufacture led to the development of the entire synthetic chemical and pharmaceutical industry that we know today. It is used as a dye and also as a stage in the synthesis of other dyes and chemicals. Unfortunately, both aniline and its derivatives, such as monomethyl-analine and dimethylaniline, are toxic. 

A recent technique to achieve a reuse of the thickener is the precipitation of the thickener by addition of organic solvent (e.g., methanol). After removal of the dyes and chemicals the thickener can be reused for the preparation of new pastes. The removed chemicals and dyes are collected and discarded [68]. By this method a considerable part of the COD-forming compounds can be recycled and the AOX and heavy metal content in the wastewater from textile printing can be reduced. 

Information Bulletin, E. I. duPont dc Nemours Co., Organic Chemicals Department, Dyes and Chemicals Division, Wilmington 98, Delaware. 

Afterwards, fabrics are usually washed to remove unfixed dye and chemicals. Vat and sulfur dyes must be reoxidized. 

In the two-phase process dyes and chemicals are applied in separate steps first dyes and thickener ( solid phase ) are printed, then chemicals and auxiliaries are added as an aqueous solution by padding. Sodium dithionite (Hydrosulfite) is used as reducing agent, and steaming time is kept short (20-40 s). For stabilized reducing agents, see [5, p. 296-298],... 

Trotman, E.R., "Dyeing and Chemical Technology of Textile Fibers", 5th Ed., Chapter 22, Charles Griffin and Company, Ltd., London, England, 1975. 

With the development of man-made fibers, a methodology was needed to color these products. Many of the prepared dyestuffs for natural fibers did not impart color to the synthesized polymeric fibers. Hoechst (Germany), ICI (England), and DuPont (America) were the pioneers to develop dyestuffs to successfully color the man-made fibers. The dyestuffs used were either coupled to the polymer or chemically bonded to the polymer in the case of reactive dyes. These dyes are generally applied to the fiber in a water solution containing the dye and chemicals designed to assist in the process. 

Compatibility compatible with acid dyes and chemicals normally used in dyeing nylon... 

SURFACTANT 49 is compatible with anionics and cationics and all dyes and chemicals normally encountered in textile dyeing and finishing. 

Hydrochloric acid (HCl) is commonly used for the neutralization of alkaline agents, as a bleaching agent, in the synthesis of dyes and chemicals, and in metal refining. 

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