In the first instance of the research, our team set out to scope the existing state of the art when it comes to biomaterials. The review showed a range of materials that demonstrate various levels of availability to market: now, near, or far. It also showed the different parts of the supply chain in which innovation could take place. The review of over 80 different materials led to creating a lifecycle map that highlights the stages of resource extraction, transformation and use of the materials, with a focus on materials from non-fossil sources. This map is based on the materials from the sample collection and built as a collaboration between the HEREWEAR partners who are involved in design and material processing. To further validate and explore the impact of designing with biomaterials across the lifecycle, we have interviewed some key materials innovators using the map as the starting point to better understand their material. There are many different types of bio-based materials that offer complementary angles on a circular future. Understanding what to look out for to reduce impacts and how to use exemplary materials adequately in well-designed products is key to the success of a circular bioeconomy.
This series of posts presents these materials and highlights how they show paths towards circular local and biobased systems that we can learn from and follow in HEREWEAR.
Terra Denim is a process for dyeing cellulosic fibres, mainly cotton, that uses clay and natural mordants. Maritas Denim, the Turkish company spearheading this process has participated in an interview using the HEREWEAR bio-based material lifecycle map to help describe their key innovations. Maritas Denim is also one of the companies involved in the Ellen MacArthur Foundation project “The Jeans Redesign”.
The Terra Denim references are made from GOTS certified cotton from the Aegean region of Turkey (1). This cotton is seen as a ‘normal high quality’ fibre with a 2-millimetre staple length. The cotton is sourced as cleaned fibres from suppliers. This means that in this case the mechanical and chemical cleaning of the fibres from the fields is done by a third party (2). However, Maritas Denim carries out all of the yarn production steps, including carding and spinning (3), in a house in their factories based in the south of Turkey. The company specialises in woven denim and other heavyweight textiles like chinos-type materials, in the case of Terra Denim, the fabric is a cotton twill containing up to 2% elastane (4).
The real crux of the Terra Denim process is in the colouring of the textiles, the dyeing (5) or the printing (6) process applied. Maritas Denim is carefully sticking to a fully biobased dyeing story, using a natural resin for the mordant, and clays for the dyeing. Not all colours are possible to achieve with this process, especially bright or neon hues are out of the question. But by mixing different clays, the dyers can respond to their client’s requests. In particular, to expand the variety of colours possible with a limited range of dyes, two different warps, one beige and one grey, are used to variate the results achieved with a single type of weft yarn. The colours can also be applied after the textile is woven as a surface dye.
Maritas Denim has experimented with garment construction including circular design guidelines, considering more sustainably sourced zippers or removable accessories (7). When collaborating with brands for the production of clothing, additional information concerning the material is provided to the user on a special hangtag, highlighting the credentials of the product.
Although the company isn’t particularly positioned in terms of the lifecycle extension aspects of the items, which is more relevant to the product designer than to the material producer, care has been given to the end of life trajectory. The low percentage of elastane (>2%) means that in theory the fabric can be recycled mechanically (8). Maritas Denim has already started recycling their cutting room floor waste in partnership with a yarn manufacturer.
Terra Denim is an example of conventional bio-based material, cotton, being used in clothing textiles with care to reduce impacts in the dying process by reducing the need for harsh chemicals and synthetic dyes. While the material is almost entirely made from bio-based resources, the small content of elastane would impede safe composting or biodegradation, therefore the company are applying mechanical recycling to offcuts and end of life products. This material is available commercially for the production of trousers and other heavyweight clothing.
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