ABSTRACT
What is textile wet processing (Leung, Lo, and Yeung 1996)? After textile materials have been made, by being spun into yarn or woven into fabric, they still contain impurities which make them undesirable for immediate use. Such textiles are usually referred to as ‘grey textiles’ or ‘grey goods’—they are unattractive to consumers because of their appearance, handle (feel), and lack of serviceability and durability. Textile wet processing is the collective term for the processes that are used to improve the textiles in terms of these properties. The most common way to examine textile wet processing is to split it into the following three stages:
1. Pretreatment or preparation 2. Colouration (dyeing and printing) 3. Finishing
The pretreatment consists of a series of chemical and other treatments which are applied to textiles at the grey stage. At this stage, the textiles cannot be dyed or printed. The pretreatment processes improve the textiles so that they are able to accept dyes and chemicals in the later stages of textile wet processing. Colouration includes dyeing which adds colour to the textiles, which would otherwise be white only, and printing which provides special design to suit consumer requirements. Without the colouration process, there would be no place for textile designers (Leung, Lo, and Yeung 1996). In addition, the consumer also expects textiles to fulfil certain end-use requirements. For example, a raincoat should at least be waterproofed, and a woollen sweater should be mothproofed. In order to meet such expectations, textiles must undergo various finishing processes. These consist of mechanical and/or chemical treatment, and take place after colouration and before the material is made up into a garment. Moreover, in the textile wet processing, various chemicals and chemical reactions are involved and have been applied to the textile materials. If the chemicals such as dyes are not all picked up by the fibres or the chemical reactions are not fully completed, a residual amount of
chemicals will be discharged. Although the amount of chemicals can be estimated and eliminated, there is still a risk of having a harmful effect on the environment.
