Method for degumming and bleaching decorticated plant bast fiber

Abstract

This is a method for degumming decorticated plant bast fiber, such as ramie, flax, or hemp bast fiber, to remove pectin-containing material and coloring gums therefrom. The decorticated plant bast fiber is desirably washed with a washing solution containing a surface active agent to penetrate the plant bast fiber and remove water soluble material and other debris therefrom. The washed plant bast fiber is then rinsed. The washed and rinsed plant bast fiber is treated with an aqueous acidic treatment solution of fungal pectinase for a period of time of between 10 and 30 minutes to remove the pectin from the plant fiber. The acidic treatment solution is maintained at an elevated temperature in the range of between 60.degree. C. and 70.degree. C. and has a pH between about 2.0 and 3.5. Thereafter, the plant bast fiber with the pectin removed therefrom, is removed from the acidic treatment solution and a sufficient amount of NaOH is added thereto to increase the pH of the treatment solution to about 11.0. The plant bast fiber with the pectin removed therefrom is then further treated in the basic solution for a period of time between about 15 to 60 minutes to remove the coloring gum adhering to the plant bast fiber. The plant bast fiber with both the pectin and the coloring gum removed therefrom is then rinsed to remove the treating solution therefrom.

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