PURE British hemp is being woven into cloth this week for the first time in a century. The hemp was grown last year in Kent, and its fibres were extracted in Bedfordshire and spun in Northern Ireland. Now the yarn is being woven into fabric at the Chelsea College of Art and Design in London. The project was coordinated by the Bioregional Development Group (BDG), which is based in London.
Hemp was an important crop in England until the late 18th century, as its tough fibres made it a valuable raw material for rope, textiles and paper. But it was displaced by other fibres, cotton in particular, following the introduction of the cotton gin 鈥� a machine for separating the cotton seeds from their surrounding fibres. Over the twenty years after the gin鈥檚 invention in 1770, the price of cotton cloth dropped a hundredfold.
Now Harry Gilbertson at Silsoe College in Bedfordshire has finally developed a comparable industrial technology. The 鈥渄ecorticator鈥�, which is able to extract fibre from the stems of crops such as hemp and flax cheaply, is now undergoing commercial trials at the college. The device was originally designed to extract useful fibres from the straw left after harvesting linseed, but also succeeded in processing samples of hemp with it. The resulting hemp fibre is now being woven into cloth.
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The machine works by crunching fibre-bearing stems between a succession of toothed rollers. The non-fibrous plant material drops away in lumps known as 鈥渉urds鈥�, while the fibre is shredded by high-speed cylinders bristling with sharp pins, and ejected in a stream of coarse fluff.
The hurds can be sold as horse bedding, and can be made into paper or chipboard. The fibrous fluff has a wider range of uses. For example, it can be pressed into a cheap industrial textile 鈥� useful as absorbent padding inside machinery, to protect bare ground from erosion, or to soak up oil from polluted water. It can also be woven into textiles suitable for clothing, or pulped into fine paper for books, banknotes and cigarette papers.
The BDG鈥檚 first hemp fibre was sent to a linen mill in Northern Ireland to be combed, carded, and wet-spun into an extremely strong but coarse yarn described by Sue Riddlestone, a director at the company, as 鈥渟uitable for jeans rather than blouses鈥�.
The fibre from a second hemp sample was extracted in Belgium on 鈥渟cutching鈥� machinery normally used to extract linen-grade fibres from flax. Unlike the Silsoe process, which yields randomly oriented fibres, the scutching maintains the alignment of fibres to produce a finer product. However, the process is labour-intensive and far more expensive.
鈥淭o reach the mass markets we need a low-cost system,鈥� says Nigel Bazeley of Robin Appel, a company which has ordered the first production model of the Silsoe decorticator for delivery early next year. The firm will begin by processing linseed straw, but Bazeley wants to move on to hemp as soon as possible. 鈥淪ome modifications will be needed for full-scale processing, because the hemp stems are three times longer and fatter than linseed straw鈥�, he says. 鈥淏ut we can see a tremendous marketing opportunity. A pair of jeans made out of English hemp will have an awful lot of cred, even if the material is a bit rough.鈥�
Clothes made out of the material will be exhibited at Redress 鈥� an eco-friendly fashion show organised by the Women鈥檚 Environmental Network for the start of London Fashion Week next March.
