Kläder i hampa - ett miljövänligt alternativ/komplement till bomull?

Sammanfattning: Hemp has been used for textiles for a long time in history until it became illegal to grow in many countries in the 1930s. It is interesting from an environmental point of view because it doesn’t need any pesticides and in most locations it doesn’t need any irrigation either, compared to cotton, which normally requires big amounts of both pesticides and water for irrigation. Hemp is a bast fiber, which means that the fibers are located on the bast of the stem (on the outer layer of the stem). Therefore they cannot be spun directly, they have to be removed from the stem first. This is done by retting and treatment with the base NaOH. This report aims to investigate the environmental problems associated with hemp fiber processing, in order to see if hemp can be an environmentally friendly material for production of clothes (and other textiles) in the future. The retting water contains organic matter (BOD = biological oxygen demand) and should not be led out directly into rivers or lakes because the retting products that are still left in the water will be degraded by microorganisms, who use oxygen and make the water free from oxygen if there is too much degradable material. In China, where much of today’s hemp for textile production is grown and produced, the retting water is used to irrigate fields. This way, the material can be broken down in the soil, before it reaches rivers and lakes. After the retting, the fibers are treated with a base (NaOH). The residue water from this process doesn’t seem to pose any environmental impact either, if treated properly. It needs biological cleaning treatment (microorganisms who degrade the material under controlled circumstances). This treatment produces a “cottonized” fiber that can be spun in cotton spinning machinery and has a good quality. The hemp industry needs investments in order for the prices to go down, but it is an interesting environmentally friendly material for clothes because of its environmental advantages and easy way to grow to grow together with its high crop yields.