A team led by Thomas Harter from the Institute of Bioproducts and Paper Technology at Austrian university TU Graz, has developed a process to recover fibres from cotton-based used textiles and use them to produce paper for packaging materials.

In Austria alone, around 220,000 tonnes of textile waste are produced every year, of which almost 80 per cent is incinerated, said the researchers. With the newly developed process, this number can be reduced.

Mr Harter stated that compared to conventional recycled paper, the paper with textile fibre content proves to be significantly stronger – a ‘major’ advantage from an environmental point of view. He added that the paper cycle is highly closed, with recycling rates of over 90 percent in the packaging sector. If valuable textile fibres are brought into this cycle, they remain usable for a long time, he explained.

Tests have shown that the addition of textiles increases the strength of recycled paper. Alexander Weissensteiner, who is also working on optimising the recycling process as a master’s student, commented: “Even with a textile-based proportion of 30 per cent, the paper is significantly stronger, while the processability remains the same. The fibre lengths of recycled wastepaper are quite short. At 1.7 millimetres, our recycled textile fibres are significantly longer.”

To make paper from old items of clothing, the clothing is first cut into small shreds and soaked in an aqueous solution. This mixture of water and shreds is milled to separate the interwoven cotton fibres without knotting or clumping. This then goes through a beating machine and is then processed to extract the maximum number of usable fibres from the textile waste.

Visually, the paper with textile content hardly differs from ordinary recycled paper for some packaging applications, it is claimed; it is slightly brownish with occasional coloured speckles, which come from coloured items of clothing, explained Mr Harter. However, these splashes of colour are irrelevant for cartonboard and other packaging materials, he added.

The researchers’ next goal is to reduce the energy consumption of the beating process. In addition to additives such as light acids and alkalis, they also test enzymatic pre-treatments to support fibre disintegration in the beating unit. “We also want to take the next scaling step and implement the process on industrial devices,” concluded Mr Harter.