260
uses heat in vacuum. The challenge lies in recycling polyester fibre-to-fibre in a
process that maintains the material quality. During this process, it is important to
ensure that the chemical substances utilized in this process and released to the environment can biodegrade safely, thus, reducing energy consumption in the recycling
processes of PET bottles (Al-Sabagh et al. 2015).
The Teijin ECOCIRCLE® system “turns polyester products into raw materials,
and raw materials into products, in a never-ending ring of recycling resources. It is
used in Fibres, PET bottles and other products. This system consumes 84% less
energy and emits 77% less CO2 than the production of polyester fibres from petroleum” (Teijin 2006). Recycling polyester is fundamental to reducing the waste generated by petrochemical feedstock as it lacks biodegradability and also has
high-energy consumption rates. The difficulty of recycling polyester textile is that
these textiles are usually blended with different materials. One of the most common
blends is with cotton, which makes the process of recycling difficult. In order to
facilitate this process, the garment should be made entirely of polyester, buttons,
zippers, labels, etc. This is the idea of DuPont, Apexa® fibre, made of a biodegradable polymer that can be spun with natural fibres such as cotton, wool, hemp and
silk. Labels, zips, tape, etc. can also be made of this polymer (Kapsali 2012).
16.2.3.4.2 Cotton Recycling
Refibra
TM
is a technology for upcycling cotton scraps from garment production. The
cotton is blended with wood pulp and spun to produce new virgin Tencel Lyocell
fibres to make fabrics and garments in a closed-loop production (Tencel Refibra
2018). “The leftovers from 16 virgin cotton shirts can be turned into one reclaimed
cotton shirt” (Patagonia 2018). The mechanical method used for recycling cotton
faces problems in material separation and produces lower-quality fibres during the
recycling process. The mechanical method involves carding machines that tear the
fabric apart. In this process, the fibres are shortened and blended with virgin material
(Fletcher 2014). On the other hand, the chemical method dissolves the cotton into
glucose synthetic fibre. The Hong Kong Research Institute of Textiles and Apparel
(HKRITA 2018) developed a bioprocess that by enzymatic hydrolysis natural fibres
such as cotton are degraded into glucose. This process offers a solution to the natural
base materials (e.g. cotton) by increasing the efficiency on the recycling process as
well as improving the fibre-to-fibre life cycle. This could also be a solution for blended
textiles, which is one of the major difficulties in post-consumer waste recycling.
16.2.3.4.3 Blended Textiles Recycling
According to HKRITA (2018), their textile waste recycling process uses a biological
pretreatment method and textile separation by hydrothermal treatment, offering a
solution for recycling cotton-polyester blended fabrics. The pretreatment method
modifies the structure of the textile waste with reusable chemicals to make them
C. Arana et al.
uses heat in vacuum. The challenge lies in recycling polyester fibre-to-fibre in a
process that maintains the material quality. During this process, it is important to
ensure that the chemical substances utilized in this process and released to the environment can biodegrade safely, thus, reducing energy consumption in the recycling
processes of PET bottles (Al-Sabagh et al. 2015).
The Teijin ECOCIRCLE® system “turns polyester products into raw materials,
and raw materials into products, in a never-ending ring of recycling resources. It is
used in Fibres, PET bottles and other products. This system consumes 84% less
energy and emits 77% less CO2 than the production of polyester fibres from petroleum” (Teijin 2006). Recycling polyester is fundamental to reducing the waste generated by petrochemical feedstock as it lacks biodegradability and also has
high-energy consumption rates. The difficulty of recycling polyester textile is that
these textiles are usually blended with different materials. One of the most common
blends is with cotton, which makes the process of recycling difficult. In order to
facilitate this process, the garment should be made entirely of polyester, buttons,
zippers, labels, etc. This is the idea of DuPont, Apexa® fibre, made of a biodegradable polymer that can be spun with natural fibres such as cotton, wool, hemp and
silk. Labels, zips, tape, etc. can also be made of this polymer (Kapsali 2012).
16.2.3.4.2 Cotton Recycling
Refibra
TM
is a technology for upcycling cotton scraps from garment production. The
cotton is blended with wood pulp and spun to produce new virgin Tencel Lyocell
fibres to make fabrics and garments in a closed-loop production (Tencel Refibra
2018). “The leftovers from 16 virgin cotton shirts can be turned into one reclaimed
cotton shirt” (Patagonia 2018). The mechanical method used for recycling cotton
faces problems in material separation and produces lower-quality fibres during the
recycling process. The mechanical method involves carding machines that tear the
fabric apart. In this process, the fibres are shortened and blended with virgin material
(Fletcher 2014). On the other hand, the chemical method dissolves the cotton into
glucose synthetic fibre. The Hong Kong Research Institute of Textiles and Apparel
(HKRITA 2018) developed a bioprocess that by enzymatic hydrolysis natural fibres
such as cotton are degraded into glucose. This process offers a solution to the natural
base materials (e.g. cotton) by increasing the efficiency on the recycling process as
well as improving the fibre-to-fibre life cycle. This could also be a solution for blended
textiles, which is one of the major difficulties in post-consumer waste recycling.
16.2.3.4.3 Blended Textiles Recycling
According to HKRITA (2018), their textile waste recycling process uses a biological
pretreatment method and textile separation by hydrothermal treatment, offering a
solution for recycling cotton-polyester blended fabrics. The pretreatment method
modifies the structure of the textile waste with reusable chemicals to make them
C. Arana et al.