Covestro: Elastic textile fibres made from carbon dioxide

Covestro announced that two research projects have succeeded in making elastic textile fibres based on CO2 and so partly replacing crude oil as a raw material. The company and its partners, foremost the Institute of Textile Technology at RWTH Aachen University and various textile manufacturers, are developing the production process on an industrial scale and aim to make the fibres ready for the market. They can be used for stockings and medical textiles, for example, and might replace conventional elastic fibres based on crude oil, said Covestro.

The elastic fibres are made with cardyon polyol that consists in part of CO2 instead of oil. This precursor is already used for flexible foam in mattresses and sports floorings – and now it is being applied to the textile industry. “That’s a further, highly promising approach to enable ever broader use of carbon dioxide as an alternative raw material in the chemical industry and expand the raw materials base,” said Dr. Markus Steilemann, CEO of Covestro. “Our goal is to use CO2 in more and more applications in a circular economy process and save crude oil.”

The fibres are made from CO2-based thermoplastic polyurethane (TPU) using a technique called melt spinning, in which the TPU is melted, pressed into very fine threads and finally processed into a yarn of endless fibres. Unlike dry spinning, which is used to produce conventional elastic synthetic fibres such as Elastane or Spandex, melt spinning eliminates the need for environmentally harmful solvents. A new chemical method enables carbon dioxide to be incorporated in the base material, which also has a better CO2 footprint than traditional elastic fibres.

Scientist Pavan Manvi from RWTH Aachen University (right) and Covestro researcher Dr. Jochen Norwig holding a synthetic fibre prototype made from CO2. (Source: Covestro)

“The CO2-based material could be a sustainable alternative to conventional elastic fibres in the near future,” stated Prof. Thomas Gries, Director of the Institute of Textile Technology at RWTH Aachen University. “Thanks to our expertise in industrial development and processing, we can jointly drive establishment of a new raw materials base for the textile industry.”

Development of the method of producing fibres from CO2-based thermoplastic polyurethane has been funded by the European Institute of Innovation and Technology (EIT). It will now be optimised as part of the “CO2Tex” project, which is to be funded by the German Federal Ministry of Education and Research (BMBF) so as to enable industrial production in the future. “CO2Tex” is part of “BioTex Future,” a project initiative of RWTH Aachen University. The initiative is devoted to developing production and processing technologies to facilitate the future market launch of textile systems from bio-based polymeric materials.

According to Covestro, the CO2-based TPU fibres are elastic and tear-proof and so can be used in textile fabrics. Initial companies from the textile and medical engineering sectors have already tested the CO2-based fibres and processed them into yarns, socks, compression tubes and tapes. The aim of launching CO2-based textiles on the market is to promote a material cycle in the textile and clothing industry based on sustainable resources, said the company.