Submitted to: American Society of Agricultural Engineers Meetings Papers
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2001
Publication Date: 8/1/2001
Citation: Anthony, W.S. 2001. Decortication of straw from seed flax. American Society of Agricultural Engineers Meetings Papers. Paper Number: 01-6079 15 pp.
Interpretive Summary: All flax fiber (linen) used by the U.S. textile industry is imported because flax is not grown in the U.S. With the increased interest in using environmentally friendly and recyclable products, flax fiber is being considered as a replacement for synthetics in many applications. A limited amount of U.S. research is underway to develop the technology to make flax fiber production viable in the U.S. One possibility is to use the stalk from seed flax which is grown for its oil and usually burned, as a source of fiber. Machinery, however, is not available to economically separate fiber from flax stalks. This research evaluated numerous machines normally used to separate foreign matter from cotton fiber for its potential to decorticate flax stalks. Results suggest that combinations of several of the gin machines are quite effective but only recover about 50% of the potential fiber. Further research is required to improve effectiveness of the gin machinery sequences and to develop new machinery.
Technical Abstract: Flax can be grown for either fiber, seed or both. All flax fibers used by the U.S. textile industry are imported from foreign countries. The seed flax stalk is usually considered a waste product but it can be separated into fiber and shive. The fiber can then be used for applications not requiring the long fiber from fiber flax such as composites and paper. The separation of fiber from fiber flax stalks is a rigorous and expensive process that requires the stalk to be biologically degraded (retted) before processing, and is not feasible for seed flax stalks. This study evaluated the effectiveness of cotton gin machinery in separating the fiber from the shive in the stalk. Machines known in the cotton industry as cylinder cleaners, impact cleaners, trashmasters, stick machines and saw-type lint cleaners were considered individually and in combination. The stalks were chopped into 5.1 cm (2 in.) lengths before they were processed through the machine treatments. The initial straw in this report contained about 20% fiber. Results of three separate studies involving over 25,000 kg (55,000 pounds) of stalks produced fiber contents ranging from 9.6 to 15.8%. The effectiveness of several combinations was about the same, but the most effective was three cylinder cleaners followed by one saw-type lint cleaner, which produced 13.7% fiber at 86.1% purity. The degree of retting is the single most important factor governing the mechanical separation of the fiber from the stalk.