PROJECT DESCRIPTION
BACKGROUND
More than 70% of airbag cushions produced in the world are made of polyamide fabrics coated with silicone. Polyamides are synthetic polymers, such as nylon, that are commonly used in textiles, vehicles, carpets and sportswear because of their extreme durability and strength. In Europe, the airbag cushion industry generates some 9 000 tonnes/year of waste. As a result of high recycling costs, such complex waste is either not exploited and dumped in Europe or shipped to emerging countries where cheap labour performs the recovery in a non-sustainable way without environmental considerations. At the same time, demand for recycled polyamide plastics is growing fast in European markets, including in the automotive industry. Consumers also want more eco-designed products. Recycled products are less dependent on petroleum-based intermediaries whose prices are volatile and have constantly increased over recent years. Technical polyamide textiles, and in particular scraps generated by the production of airbag cushions, were identified by the beneficiary as an attractive source for developing new recycling technologies and processes. The company’s R&D team developed an integrated process to recycle and re-use the silicone-coated polyamide fabrics in new materials with no loss in material properties at small scale.
OBJECTIVES
The main objective of theMove4earth project was to validate a new process for recycling and re-using silicone-coated polyamide fabrics from airbag cushions at pre-industrial scale. The project team aimed to demonstrate the feasibility of the process, to obtain an acceptable final product in terms of quality and unit productivity. They planned to develop and operate a demonstrator, recycling 650 kg/h of silicone-coated polyamide fabrics. The aim was to test the recycled materials to assess their mechanical properties in comparison with non-recycled materials. It was thus hoped to reduce the quantity of waste going to landfill or being shipped to emerging countries, and also reduce the carbon footprint associated with demand for new raw materials from petrochemical sources.
RESULTS
The Move4earth project team designed and built a pilot plant to demonstrate a new process for recycling and re-using silicone-coated polyamide fabrics from airbag cushions at pre-industrial scale. A detailed engineering study was firstly conducted to define specifications for each piece of process equipment and to design the layout of the demonstrator. Based on this study, the project team renovated a building to host the demonstrator. Then the pieces of equipment were purchased and installed.
The validation and optimisation of the recycling process involved discontinuous evaluation of all the main equipment and process steps individually, and then together after construction continuously during a 48-hour test run. The technology was fully demonstrated to be industrially robust and ready for future scale up. The high quality of the polymer obtained and the compliance of the liquid effluents generated by the process were also validated.
It was important for the beneficiaries to identify high-value applications for the recycled polymer. A new range of high-quality recycled compounds (branded as "Technyl4earth) was created and successfully promoted thanks to a toolkit developed for sales officers. Commercial applications were launched in various markets, such as for automotive, building and construction, and consumer appliances.
To minimise the environmental impacts of the technology and increase its economic viability, the beneficiaries looked for valorisation options for the silicone residues generated during the recycling of silicone-coated airbag fabrics. A first solution, rapidly identified and implemented, consisted of mixing the silicone residues with other Solid Recovered Fuels (SRF) used to produce energy. Overall more than 40 prospects were identified with companies contacted along several value chains for potential applications, such as plastics, elastomers, transportation infrastructures, building and construction. One promising application identified, for instance, was to use silicone residues mixed with polyolefins to make flowerpots, mail boxes or light roofing systems.
In addition to airbag cushion scraps generated from the manufacturing process, the project team evaluated the potential of the Move4earth technology to recycle other technical textile wastes, namely, post-consumer airbag cushions and polyamide/elastane fabrics. They showed the feasibility of recycling post-consumer airbags and developed a protocol for doing so. Three tons of dismantled cushions were processed at the Move4earth demonstrator. The quality of the recycled polymer obtained from this first trial was slightly lower compared to the one made from post-industrial scraps, but still enough to envisage future optimisations for technical compounds. The Move4earth project team intends to start new collaborations to develop the recycling of post-consumer airbags in Europe, though new solutions are needed to reduce dismantling costs and optimise waste collection.
During its lifetime, the project delivered significant direct environmental benefits through the use of more than 1 500 tons of recycled polymer instead of virgin PA66 polymer to produce polyamide 6.6 engineering compounds, with more than 3 000 tons of CO2 emissions avoided, and more than 36 400 m3 of water and 113 850 000 MJ of primary energy saved. Based on average annual CO2 emissions and energy consumptions of European households in 2016, those results correspond to a CO2 reduction corresponding to the equivalent emissions of 427 European citizens and energy savings corresponding to the equivalent consumption of 978 European citizens in 2016.
The project team highlighted the need for legislation and regulation evolution to support the further development of this technology. They suggested amending the End-of-Life Vehicle Directive to encourage dismantlers to extract airbags and make them available for recycling, and creating new legislation offering positive financial incentives to companies that increase their use of high-quality recycled polyamide plastics.
The project generated financial revenues of millions of euros, derived from the tons of recycled plastics and polymers reused. Besides, 18 jobs were specifically created, and they will be sustained in the future. More positions could open if the technology gets to a higher degree of market uptake.
