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The winch dyeing process involves the movement of fabric, while the dye liquor remains stationary. The dye bath is heated through the heating coils within the front compartment to a maximum temperature of 95-98 degrees Celsius. The winch dyeing process has a high specific liquor ratio of around 1:20 to 1:40.
Substantive dyes work best on textiles with high contents of cellulose, such as cotton. In contrast to direct dyes, wool and leather goods are dyed by the process of ion exchange, exploiting the cationic nature of proteins near neutral pH. The development of substantive dyes helped make mordant dyes obsolete. [2]
Textile dyeing plants generate wastewater that contains synthetic (e.g., reactive dyes, acid dyes, basic dyes, disperse dyes, vat dyes, sulfur dyes, mordant dyes, direct dyes, ingrain dyes, solvent dyes, pigment dyes) and natural dyestuff, gum thickener (guar) and various wetting agents, pH buffers and dye retardants or accelerators.
During the dyeing process, the dye must become close and even with the material in order to produce a uniform color that is fast to moisture, heat, and light. [5] Due to their superior fastness properties and simple application, reactive dyes are currently the most common type of dye for cotton dyeing. [6] The CPB technique uses less water and ...
Also called direct dyes, substantive dyes are employed for cellulose-based textiles, which includes cotton. The dyes bind to the textile by non-electrostatic forces. In another classification, azo dyes can be classified according to the number of azo groups. Trypan blue is an example of a direct dye, used for cotton.
Direct or substantive dyeing is normally carried out in a neutral or slightly alkaline dye bath, at or near boiling point, with the addition of either sodium chloride (NaCl) or sodium sulfate (Na 2 SO 4) or sodium carbonate (Na 2 CO 3). Direct dyes are used on cotton, paper, leather, wool, silk and nylon.
Some dyestuffs, such as indigo and lichens, will give good color when used alone; these dyes are called direct dyes or substantive dyes. The majority of plant dyes, however, also require the use of a mordant, a chemical used to "fix" the color in the textile fibres. These dyes are called adjective dyes or "mordant dyes". By using different ...
Vat dyes are a class of dyes that are classified as such because of the method by which they are applied. Vat dyeing is a process that refers to dyeing that takes place in a bucket or vat. The original vat dye is indigo , once obtained only from plants but now often produced synthetically.