PROJECT DESCRIPTION
BACKGROUND
Polyester is the second largest family of plastics by quantity of used material. In 2009, half of the 1.75 million tonnes of polyester textiles produced in the EU was used to make clothing. The properties of polyester-based textiles make them especially suited for the footwear sector, where they have been introduced in many parts of the shoe (collar, tongue, insole, lining, tip and leg). However, up to 7% of high-grade polyester textiles is lost during manufacture. This waste is mainly composed of trimmings and rejections that often contain polyester mixed with other materials, including glues. For this reason, recycling using traditional mechanical methods is not possible as it is difficult to separate the contaminants from the plastic efficiently, making landfilling and incineration the only solution. Polyester waste from footwear manufacturing is an area that requires further efforts to find economically viable and sustainable management solutions.
OBJECTIVES
The LIFE-ECOTEX project proposed an innovative, eco-efficient and highly replicable recycling system for polyester textile waste generated by shoe manufacturing. The aim was to close the cycle for polyester material, making it possible to replace a part of the non-renewable petrochemical feedstock used to make textile polyester with rejected shoemaking material. The process would start with the chemical de-polymerisation of polyester waste to recycle polyethylene terephthalate (PET) and produce bis (2-hydroxyethyl) terephthalate (BHET) by catalytic glycolysis. Once purified, the recovered BHET (having identical properties to equivalent ‘virgin’ material) would be a suitable building block for the synthesis of fibre-grade polyesters. These recycled materials could then be reintroduced in the market for footwear manufacturing or as non-woven insulators for construction.
RESULTS
The LIFE-ECOTEX project demonstrated the feasibility of closed-loop recycling of waste polyester synthetic textiles associated with the footwear sector. Recycling avoids the landfilling of PET textile wastes generated in shoe manufacturing and provides an alternative solution to the current end-of-life scenario. It also showed the possibility of producing high added value BHET monomers from polyester waste. These monomers were then re-polymerised to obtain chemically recycled PET with a similar quality to virgin PET. The recycled PET was used to produce polyester staple fibre (PSF) that could be used in the manufacture of non-woven felts. To complete the loop, these non-woven felts are then used in the manufacture of marketable products, such as shoe insoles and insulation panels.
Specific results include:
- Selective collection of post-industrial polyester textile wastes from footwear sector, analysis and determination of the composition and physical properties;
- Start-up and fine tuning of the glycolysis pilot plant and purification system;
- Treatment of 550 kg of waste;
- Production of more than 350 kg of purified BHET, with a purity of greater than 95%;
- Manufacture of 300 kg of renewable PET;
- Production of 800 kg of PSF to be used for obtaining non-woven textiles;
- Reduction in greenhouse gas emissions of 1.04 tonnes of CO2 per tonne of PET produced (in the form of pellets); and
- Creation of prototypes, including 330 shoe insoles and 24 insulation panels manufactured with the non-woven textiles.
The innovation and demonstration value of the proposed process has been demonstrated since a new chemical route, based on catalytic solvolysis of waste polyesters, has been successfully tested at demo scale.
The economic impact assessment identified the de-polymerisation of PET waste to obtain BHET without purification and the chemical recycling involving the de-polymerisation/re-polymerisation of PET to obtain recycled PET as the most profitable processes. It is expected that 15 to 45 full-time job positions will be created in local companies directly as a result of the close-loop recycling system for PET footwear waste. At least 80% of the jobs will be in the industrial implementation of the recycling process, with the remaining 20% in the manufacture of footwear textiles with recycled PET.
The project team contacted many enterprises to encourage replication of the process, with 26 from the footwear sector expressing an interest. Moreover, businesses in the packaging and automotive sectors have also shown interest due to the high amount of PET waste that they generate.
