The Third International Conference on Biobased Textiles in Ghent, Belgium on October 16 demonstrated rapid progress in research and development, but the biobased textiles segment still remains handicapped by uncompetitive prices, Jozef De Coster reports.

Many businesses in Europe have the ambition to introduce and use biobased polymers in textile applications. Biobased polymers (or, biopolymers) are increasingly commercially available and production capacity shows an impressive annual growth rate of almost 20 per cent worldwide.

However, taking into account the still marginal market position of biopolymers, the current growth rate is too little to ensure a swift transition to sustainable textile production and consumption. The price of biobased textiles is mostly too high. Governments should develop policies to reduce the use of unsustainable fibres in favour of raw materials obtained from biomass, and preferably from waste.

Biobased textile fibres are not new. Nearly 130 years ago, in 1891, British chemists discovered how to make viscose from cellulose (from wood or cotton). The company Courtaulds bought the patents on the production processes. Industry historians remark that the era in which textile production and consumption has been dominated by synthetic fibres will constitute only a short intermezzo in the long history of textiles. The first totally synthetic fibre (nylon, a polyamide fibre) was detected in 1938. Then, a lot of other synthetic fibres emerged, like the highly successful polyester fibre, and fibres like polyacryl, polyethylene, popypropylene, aramide.

But it appears that after less than a century of market dominance by oil-based synthetic fibres, the textiles industry is returning to fibres made of biomass. Belgian research institute Centexbel, which organised the 3rd International Conference on Biobased Textiles on October 16, invited some twenty researchers from several Euopean countries to present the problems and results of their work.

A revolutionary raw material: CO

Researchers from ITA, the Institute for Textile Technology of Aachen University (Germany), promote the idea that the worldwide textiles industry should make the transition to what they call 'biopolymers of the third generation'. They argue that the textiles and fashion sector should abstain itself from competing for biomass with the food and feed sector. First generation natural polymers, like starch, and second generation synthesised polymers like PLA, may indeed be sustainable resources. And yet, it's preferable to use third generation polymers, this means polymers made from waste, like polyhydroxbuturate (PHB). Why? Because in a circular economy waste reduction is an important aim, and because food and feed-not textiles-should get priority to use biomass.

The German project CroCO2PETs (Cross-linkable CO2-polyether polyols) has the ambition to use carbon dioxide (CO2), an abundantly available gaseous waste product from industrial and houselhold processes, as a raw material in polymer production. At the same time, the project intends to contribute to climate protection by means of carbon capture and utilisation. The project aims at a reduction of up to 3 kg CO2-equivalent greenhouse gas emissions by the incorporation of only one kg CO2 into CO2-PET. Taking into account the global polyol production, these new polymers have the potential to reduce greenhouse gas emissions by an order of magnitude of 1 million tonnes per year. Moreover, the utilisation of CO2 as raw material vitalises an alternative carbon source, which can significantly reduce fossil depletion by chemical production.

The project is coordinated by Covestro AG, Leverkusen, Germany, a manufacturer of polymers and high-performance plastics. Covestro AG has successfully developed technology to develop carbondioxide based thermoplastic polyurethane. Now, in cooperation with researchers and manufacturers, the intention is to develop a textile process chain to establish carbondioxide-based thermoplastic polyurethane (CO2-TPUs) into the textiles industry. ITA has developed a spinning process at technical scale for CO2-based TPU. Among the first products from melt-spun CO2-based TPU filaments that are on show are: covered yarn, elastic tape, socks and stockings.