Dyeing of Polyester
category
Polyester is dyed exclusively with disperse dyes (non-ionic, low-solubility dyes dispersed in water) under high-temperature/high-pressure (HT/HP) conditions (130°C, 3 bar) or at atmospheric pressure with carrier. The hydrophobic, dense PET structure requires elevated temperature to increase free volume for dye diffusion. Dyeing of polyester is one of the most technically and academically demanding areas of textile coloration.
Role
Polyester dyeing underpins the coloration science curriculum in textile chemistry, integrating dye chemistry, polymer physics (diffusion theory), process engineering, and environmental chemistry. It is a major industrial process consuming significant energy and water.
Subtopics
- Disperse Dye Chemistry and Classification Disperse dyes are hydrophobic, non-ionic, low-MW (250–500 Da) colorants with low aqueous solubility …
- HT/HP Dyeing Process and Equipment HT/HP dyeing of polyester at 130°C in pressurised jet dyeing machines (autoclave, pressure 2–3 bar).…
- Dye Diffusion and Free-Volume Theory Disperse dye diffusion into PET is governed by free-volume theory: above Tg, polymer chain mobility …
- Carrier Dyeing at Atmospheric Pressure Carriers are organic compounds (biphenyl, methylnaphthalene, butyl benzoate) that swell and plastici…
- Dye Exhaustion, Adsorption Isotherms and Fixation Disperse dye adsorption on PET follows Nernst (partition) isotherm for small dyes (C_fibre = K·C_sol…
- Reduction Clearing and Aftertreatment After HT/HP dyeing, surface-adsorbed (unfixed) disperse dye is removed by reduction clearing: sodium…
- Colour Fastness Properties and Testing Colour fastness of polyester: wash fastness (ISO 105-C06, rating 1–5), light fastness (ISO 105-B02, …
- Thermosol Dyeing of Polyester Fabric Thermosol process for continuous dyeing of woven polyester: pad (disperse dye dispersion, 60–80°C) →…
- Cationic Dyeable Polyester (CDP) and Ionic Dyeing Cationic dyeable polyester (CDP) incorporates 5-sodium sulphoisophthalate (SIIS, 2–3 mol%) during po…
- Dyeing Wastewater Treatment and Effluent Standards Polyester dyehouse effluent contains: residual disperse dye (colour, COD), dispersants (anionic surf…