Recycled fibre from old clothes
Photo: Pekka Karppinen. Marjo Määttänen and Ali Harlin demonstrate how cotton separated from used textiles is gradually transformed into recycled fibre.
An article from Special international issue, published in 31.5.2017.
The European co-operation project to promote the recycling of textile waste has reached an exciting phase for the VTT Technical Research Centre of Finland. Industrial manufacture of cotton-based recycled fibre is to be tested for the first time.
The production environment for the defibration pilot project was built during spring at VTT’s Bioruukki piloting centre in Kivenlahti, Espoo. The centre converts bioeconomy strategies into actual experiments. The dissolving and spinning phases of the secondary fibre manufacturing process are carried out in the piloting hall. The preceding phases (the chemi-mechanical pretreatment of waste textiles and the carbamation of cotton) are partially carried out at VTT’s other facilities.
When Uusiouutiset (Finnish Recycling News) visited Bioruukki at the end of April, equipment installation was underway. The first deployment test of the dissolution phase was to be started immediately after the first of May, and the deployment of the spinning machine was scheduled to the end of May. The first batches of recycled fibre are expected to be ready before Midsummer.
The missing link
Research Professor Ali Harlin explains that combining the pretreatment, dissolution and defibration has been the missing link in the textile recycling value chain.
‘Some call it the Holy Grail of textile industry. Before this, industrial-scale recovery of fibres from worn-out low-quality products has not been possible.’
Solutions familiar from the pulp industry are applied in the manufacturing of recycled fibre.
‘In defibration, an alkaline solution is precipitated in an acid bath, so that the cellulose becomes precipitated and fibres are obtained that can be used for making yarn or other products,’ Senior Scientist Marjo Määttänen explains.
Now it will be seen how the technology works outside the laboratory.
‘It must be possible to run large processes uninterrupted 24/7. We must ensure that there are no problems with the circulation of chemicals or the equipment, in order to avoid long shutdowns and a high waste rate,’ Mr Harlin describes the objectives of the piloting.
According to Mr Harlin, ioncell defibration technology will possibly be included in the pilot project. The technology has been developed in co-operation by Aalto University and University of Helsinki. With the ioncell method, it is possible to produce high-quality textile fibres from cotton- and wood-based cellulose in an environmentally friendly manner.
Progress through co-operation
The funding of the pilot comes mainly from the European Regional Development Fund, but there are also Tekes project funding and VTT’s own resources involved. Corporate financing has also been sought for actively: in addition to the industrialisation of the manufacturing process, the objective is the commercialisation of recycled fibre.
A startup company has been established for the project. It will produce sample batches for textile industry companies.
‘They will have the opportunity to test whether they can use recycled fibre as raw material,’ Ms Määttänen explains.
The first purchase agreements have already been signed. The achievement of the goals will not depend on the availability of material, providing that the collection of used textiles can be organised efficiently. Finland produces 72 thousand tonnes of textile waste every year, and roughly one third of it is cotton: old jeans, t-shirts, towels, sheets, etc.
Mr Harlin points out that textile waste is anything but homogenous raw material.
‘We must collaborate with parties that manage other material flows that come as byproducts of cotton, such as polyester. The development of the overall value chain is challenging but necessary in order to be able to deploy an individual technology.’
The textile and clothing industry is aware of the importance of recycling for the future of the industry and the acceptability of production. The production capacity for cotton has not increased for ten years, and environmentally conscious consumers want responsible options.
One of the companies participating in the pilot project is Touchpoint. The company’s mission is to be the forerunner in responsible work clothing in Finland.
‘We want to contribute to the promotion of circular economy projects. The defibration pilot project is a natural continuation to this work,’ explains Arja Paakkola-Saarinen, who is in charge of design at Touchpoint.
‘The project is unique in its innovativeness, and it gives us the opportunity to develop networks with other players in the recycling chain. We expect the defibration test to be successful, so that the innovation can be converted into commercial production volumes.’