Newsletter: July 2005  

Textile Wet Processes and Practices – Objectives and Importance

r Yong Kok Swee

An enormous quantity of chemical products, includes dyes, chemicals and auxiliaries, used for textile wet processing in respect of the high pollution of effluent and the need for expensive elimination of this effluent pollution, in view of the fact water treatment costs are in the end paid by the textile wet process industry causing the pollution and not from the petty cash. The necessary use of chemistry and disposal of the chemicals rather shows up enormously unfavourably in the book precisely in textile production countries where environmental consequences are of priority in view of the keen competition. 

Responsible and thorough textile wet processing is impossible without chemistry. This is actually the conclusion which should be drawn. By the example of cotton, which includes high contamination of natural fibres with herbicides, pesticides and insecticides from germination to harvesting. The high contamination of natural fibres quite simply requires correct pre-treatment of the textile goods so that both the natural and necessary concomitant substances and also all the hazardous substances are removed cleanly from the fibres material. There should be no dyeing of the untreated goods and therefore transportation of pollutants as far as the washing machine of the final consumer. 

Dyeing with the necessary high fastness properties so that non-bonded dyestuff does not get onto the skin is impossible without chemistry. And finally, only textile finishing by chemical and physical treatment methods guarantees the usability and easy care properties promised by the advertisement and expected by the purchaser, because in the end hardly anyone wants to dispense with the functional capacity and compliance with all the quality requirements in the form of a compromise between the idea and implementation. Unfortunately there is often a wide gulf between morality in environmental matters and personal actions. Anyone who rejects textile finishing must also accept the consequent compromises, and precisely these can also easily head off in the wrong direction. Prefect textile finishing using conscientiously chosen amounts and processes is better than textiles “left to nature”. The same also applies to the relationship between textile and the environment, which is control by complex environmental regulations which are almost completely foreign to many completing textile manufacturers in the developing countries.   

The buyer expects quality features and the intended use to met. Textiles must be fashionable, chic in appearance and cut, function in wearing properties, optimum in use and easy-care, inexpensive in cost/benefit ratio and physiologically acceptable in wearing properties. This quality as the agreement between planning and implementation or “fitness for use” is only possible by proper skiful and conscientious textile wet processing – which must be accepted. 

Aim of Textile Wet Processing: Gentle Chemistry in the Treatment of Textiles  

When ecology is mentioned in connection with the textile production, definite stipulation or definition of the relevant ecology field is required. The ecological textiles production includes:

Production ecology: Ecological parameters which are relevant to textile production, such as effluent, exhaust air, dyes and chemicals usage, etc.

Human ecology: The potential effects of textiles on the human skin or in the human organism, e.g. by chemicals, dyestuffs, etc.

Disposal ecology: The fate of textiles after the wearing stage, such as disposal, burning, recycling, etc. 

Since there is “no life without chemicals”, all matter, everything living, is based on chemical substances or on chemical processing cycles. Synthetic chemistry is generally perceived as so called “hard chemistry”, and condemned. Nature and its products are therefore the good, clean things to be aimed for, certainly a plausible but much too simple and one-side position. In this respect, current textiles ecological production trends lead to diverse conflict situation. 

 “Gentle chemistry” to all intents and purposes requires acquires the close attention in the treatment of textile goods as our 2^nd skin as does careful cosmetic care of our skin. What is not expected of cosmetic care should also taboo for the textile goods worn directly on this skin, and that means chemistry only to the extent necessary in the sense of gentle, protection and caring. 

The path of “gentle chemistry” fires and fabrics production, dyeing and printing, finishing, clothing production, marketing and final consumer affects all links in the textile production and marketing chain. 

The path of “gentle chemistry” in treatment of textiles are tabled as following:  

·         Selection of fibre consignments of low contamination by submitting requirement; 

·         Least possible contamination for reliable further processing;

·         Selection of ecological lubricant and chemicals for yarns and threads finishing; 

·         Easily removable preparations and sizes;

·         60% of the effluent pollution in cotton wet processing occurs in desizing, to solves the effluent problems by ultra-filtration and to reuse sizing agent and water; 

·         Thorough pretreatment, purification, extraction;

·         Selection of acceptable ecological auxiliaries and processes;

·         Minimal chemical contamination;

·         Removal of the reaction products by rinses;

·         Increase used of biological treatment processes;

·         Consistent rejection of ecologically unacceptable requirement;

·         Single-stage scouring and bleaching, if possible;  

·         Determination of substance – specific dangers by the producer;

·         Selection of dyestuffs and pigments which can not be split into MAK A I and A II carcinogenic amines in reductive conditions

·         Selection of effective and ecological dyeing and printing auxiliaries and processes;

·         Liquor recycling – dyeing in standing bath;

·         Increasing the fixation yield in dyeing and printing, especially reactive dyeing and printing;

·         Minimal dyes and chemicals contamination;

·         Removal of unfix dyes after dyeing and printing by thorough wash-off and rinses;

·         Methods and techniques to reduce exposure; 

·         Increasing use of biological and physical finishing process;

·         Selection of new textile finishing agents and processes with the aim of easier application, optimisation of effects and optimum environmental compatibility;

·         Statement of type of finishing and relative contents;

·         Reduce the properties profile to ecological responsible and technically realizable;

·         Choice of materials according to ecological quality and not cost;

·         Use and properties “passport” according to the level of understanding of the normal consumer; 

·         Correct choice of articles;

·         Correct consultation;

·         Correct clarification; 

·         Selection of textiles according to:

u      Appropriateness, not only fashion;

u      Ecological acceptability;

u      Care treatment;

·         Reduce expectations to the feasible

·         Wash all textiles worn close to the body beforehand 

If the dyes, Chemicals and textile auxiliaries used in wet processing of textiles are chosen properly, recipes are designed conscientiously in the choice and amount of components and the correct technology is used, textiles are neither unacceptable nor hazardous. Hazardous dyestuffs, chemicals and processes are still entirely common elsewhere, since there is still a considerable difference on ecological conscience, in legal regulations and in the state of knowledge, the longer the path of the textiles to the individual market.  

Contamination limits or a type of ecological controlling seems necessary, but hardly feasible. The needs of fashion, the market and consumers cannot be met without chemistry. However, an ecologically awareness is possible and necessary for the operating staffs, resulting in reduction in the amount used and selection of products and processes and minimized the cost in effluent treatment. 

The obviously again requires compromise, because expectations which have risen too high will be some drawback. Some textile product designer and the market demands, the clothing industry and the trader are not realistic, requires for unreasonable residue- free textiles goods, that is goods should be thorough rinse after final finishing. Although thorough rinse will remove some of the surplus chemicals, but total removal of contaminated chemicals still is cannot be total guarantee.

The path of  “gentle chemistry” in the treatment of textiles is not only the concern of textile chemistry and the textiles wet processing industry, it is a task of all the links in the fibres production, textile production, dyestuffs and textile auxiliaries manufactures, marketing and consumer chain. What is to be understood here by the path of gentle chemistry in textile treatment is shown by the way, encompasses all the links in the long chain to the final consumer.

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