Textile Recycling Technologies, Colouring and Finishing Methods

Fibre 
Dye Class 
Type of Pollution 
from Dye 
Pollution 
Category 
Other Chemical 
and Finishing 
Effects
Cotton 
Direct 
Salt 
Unfixed dye (5-30%) 
Copper salts 
Cationic fixing agent 
1 
3 
5 
Large amounts of 
chemical resources 
required during 
production. Must be 
treated with 
chemicals to absorb 
dyes (pre-treatment 
and post-treatment).
Reactive 
Salt, Alkali 
Unfixed dye (10-40%) 
1 
3 
Vat 
Alkali, Oxidising agent 
Reducing agents 
1 
2 
Sulphur 
Alkali, Oxidising agent 
Reducing agents 
1 
2 
Wool 
Mordant (Chrome) 
(banned) 
Organic acid 
Heavy metal salts 
2 
5 
Preparation steps 
often involve harsh 
chemical treatments. 
Acid; Metal complex 
(single-stage 
application; dye and 
mordant combined 
prior to dyeing) 
Organic acid 
Unfixed dye (5-20%) 
2 
3 
Polyester Disperse 
Reducing agents 
Organic acid 
Carriers 
Unfixed dye 
2 
5 
3 
Heavy metal 
catalysts (antimony) 
used in production, 
carcinogenic. 
Dyeing requires, 
high temperatures. 
Nylon 
Disperse 
Reducing agents 
Organic acid 
Carriers 
2 
5 
Production emits 
nitrous oxide gas.
Reactive 
Salt, Alkali 
Unfixed dye (10-40%) 
1 
3 
Table 15: Pollution Category Ranking Based on Dye Methods Applicable to Fibre Types. 
145,149 

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Textile Recycling Technologies, Colouring and Finishing Methods | Le 
43 
Finishing processes on textiles include mechanical and chemical methods. Chemical finishing 
methods may assist with reactions such as dye fixing or cross-linking agents, or impart functional 
properties and improved characteristics of the textiles.
147
 
Common chemical finishing methods include the following:
-
Colouration (dye-fixing agents) 
-
Flame resistance 
-
Easy-case (crease/wrinkle resistance) 
-
Antimicrobial or odour resistance 
-
Water-repellency 
-
UV protection 
-
Moisture wicking 
-
Abrasion resistance 
-
Stain resistance 
-
Antistatic treatment 
Some finishing chemicals of concern outlined by the Safer Made Report
20 
along with alternatives 
(under development and commercially available), are summarized: 
Finishing 
Chemical/Solvent 
Function 
Alternative Chemicals (under development, commercially 
available) 
Formaldehyde, 
other short-chain 
aldehydes 
Easy-care, 
wrinkle free 
-Polycarboxylic acids (PCA), citric acid (CA) and butane tera 
carboxylic acid (BTCA), CA/xylitol
151
have been demonstrated 
Halogenated 
Flame Retardants 
Flame retardant 
-Phosphorus, or Nitrogen (melamines) based, and inorganic flame 
retardants on cotton, polyester, and polycotton blends 
-Patented atmospheric plasma/UV laser technology on viscose/flax 
and cellulosic textiles (MTI-X Ltd.)
152,153
Commercial: Basofil® melamine fibre, Lenzing FR® flame 
resistant cellulosic fibre, Zoltek Pyron® fibres, Trevira CS® 
(phosphorus based), Green Theme International HDF™ (high 
definition finish) 
Triclosan and