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Colorants Brief classification of colorants according to application type:
- Acid dyes
- Direct dyes
- Reactive dyes
- Vat dyes
- Sulphur dyes
- Disperse dyes
- Basic dyes
- Chrome dyes
- Azoic dyes
Cotton Constituents, structure and properties. Hydrocellulose, oxycellulose. Action of acids and alkalis. Mercerization.
Water Impurities, pH, purification, hardness and effluent treatments.
Detergents Soap, anionic, cationic, amphoteric and nonionic.
Preparation Singeing, desizing, scouring, mercerisation. Bleaching (hypochlorite, chlorite, peroxide), fluorescent brightening agents. Advantages and disadvantages of various bleaching agents.
Theory of Dyeing Dyeing of cellulose with direct dyes.
Direct Dyes Properties and application. Aftertreatment.
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Sulphur Dyes Application to yarn, knitted goods, woven fabrics. Pad, jig, pad-batch, continuous dyeing, pad-steam. Polyester/cellulosic blends. Effluent treatment. Fastness properties, common faults.
Vat Dyes Types, reducing agents, vatting, batch dyeing. IN, IW and IK classes. Semi-pigmentation, pre-pigmentation, acid leuco and continuous methods. Loose stock, sliver, yarn (packages and hanks), woven, semicontinuous - continuous, knit goods, faulty dyeing, solubilised vats.
Azoic Dyes History. Coupling components. Diazo components., Continuous and batch dyeing of stock, sliver, tow, hanks and knitted goods. Fastness properties.
Reactive Dyes History and chemistry. Cold dyeing, hot dyeing types and reactivity. Package, winch, jets, semi-and fully-continuous sequences possible. Aftertreatments and fastness problems.
Pigments Types and application methods.
Polyester/cellulosic Blends Blends Dyeing procedures for polyester/cellulosic blends.
Colour Selection Dyestuff selection versus colour range. Reasons for selecting a certain class of dye, eg fastness, hue and cost.
Finishing Sequences Resin finishes for crease resistance. Special finishes for stain repellency, flame retardancy, waterproofing and softening.
Machinery Machinery used in processing.
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