Textile Recycling Technologies, Colouring and Finishing Methods

3.4.2.2 Chemical Recovery 
Chemical recycling of wool textiles is not practiced, however, research and development into the 
recovery of keratin protein from pre- and post-consumer waste has been demonstrated for use in 
other applications including, biomaterials, and resins and adhesives.
Other notable research has involved the protein recovery from waste or recycled wool for use as 
functional treatments in wool fabric production. Work by Smith and Shen, applied extracted 
polypeptides (protein molecules) from low quality waste wool as a means of surface modification 
to the fibre surface, to improve the shrink resistance.
112
Du 
et al.
successfully demonstrated an 
anti-felting/anti-pilling finishing process on wool fabric by a fixation treatment using keratin 
polypeptides extracted from recycled waste wool.
113
Improvements in softness, dyeability, and 
hydrophobicity were also observed in the modified fabrics.
113
Examples of chemical recovery processes are listed in Table 10.
 
Table 10: Examples of Keratin Chemical Recovery Processes from Wool.
112-115 
114,115 
Input 
Process 
Output/Product 
Application 
Low quality 
waste wool 
Pre-consumer 
Post-consumer 
Alkali hydrolysis 
Ionic liquid 
Sulfitolysis 
Reduction 
Oxidation
Keratin protein 
-Biomaterials, 
biopolymers: wound 
healing 
-Animal feedstock 
Waste wool 
RESYNTEX 
biochemical process and 
resin synthesis 
Protein hydrolysate 
extraction to obtain 
resins and adhesives 
Bio-based resins and 
adhesives 
Low quality 
waste wool 
Polypeptide protein 
extraction, surface 
modification of wool 
fibre by enzymes 
Machine washable wool through an 
alternative shrink-resistant finishing process
Recycled wool 
Keratin polypeptide 
extraction, fixation 
treatment 
Anti-felting/anti-pilling finishing