Textile Recycling Technologies, Colouring and Finishing Methods

Teijin 
53
 
(Japan) 
Post-consumer apparel 
material accepted from 
their Eco Circle 
program. Minimum: 
80/20 PET/cotton, 90/10 
PET/nylon, and 80/20
PET/rayon blends
36
 
ECO CIRCLE™ 
fibres, textiles 
(apparel, interiors, 
household goods, 
industrial materials) 
ECO CIRCLE™ recovery system 
comprises a chemical process to recover 
DMT, and decolourization process (heat 
and solvent) to remove dyes and impurities. 

---

Textile Recycling Technologies, Colouring and Finishing Methods | Le 
18 
3.2 Nylon 
3.2.1 Summary 
Nylon is a widely used synthetic polymer material for various applications and is also the generic 
term for polyamide-based materials. Nylon-6 and Nylon-6,6 comprise approximately 85% of 
nylon material used.
33
Main commercial applications for nylon include, fibre, packaging/films, 
carpet, and component parts most commonly found in the automotive industry.
54
Nylon is 
characterized by its high strength, elasticity, wrinkle-resistance, and higher moisture regain than 
polyester.
3 
While nylon production holds a lower proportion than polyester in annual synthetic 
fibre production, it requires more energy to manufacture, and nearly three times as much as 
conventional cotton.
55
Dyeing nylon is not suited to natural or low-impact chemical dyes, and is 
thereby another contributing factor to the environmental impact from its production process.
56
Nylon derived microplastic pollution in aquatic environments has been found to originate from 
nylon fishing nets (with total fishing net waste accounting for 10% of ocean waste), and synthetic 
textile fibres from laundering.
 56 
Nylon-6 is produced from the ring-opening polymerization of a single monomer, 
Ɛ
-caprolactam 
–forming polycaprolactam (Figure 9). “6” is denotes the 6 carbon atoms that comprise 
caprolactam. 
Figure 9: Polymerization of Nylon 6 (general process). [57,58] 
Nylon-6,6 is produced by combining two monomers – adipic acid (AA) and hexamethylene 
diamene (HMD) acid (or HMDA), with water, also known as a polycondensation reaction 
(Figure 10). “6,6” denotes the 6 carbon atoms in each of the two monomers (AA and HMD) 
which comprise the polymer.
Figure 10: Polymerization of Nylon-6,6 (general process). [58,59] 

---

Textile Recycling Technologies, Colouring and Finishing Methods | Le 
19 
Nylon-6 fibres exhibit high elasticity and lustre and are commonly used for carpet fabrics and 
rope.
60
Nylon-6,6 is characterized as being more wear resistant and durable than Nylon-6, with a 
slightly higher melting temperature.
61