GB458310A - Improvements in the preparation of sisal fibres for manufacture into yarns or similar articles - Google Patents

Abstract

Sisal or similar hard fibre of the Agave family is prepared for fine spinning by a treatment comprising softening some of the gums in the fibre by subjecting the completely decorticated fibre to the action of weak caustic alkali solution at atmospheric temperature and pressure, and thereafter removing the alkali and all or most of the softened gums. The fibre is preferably pressed after the alkali treatment and then washed and if desired again subjected to pressure. Washing may follow the alkali treatment directly without intermediate pressure treatment. The caustic soda solution should be from 2--6 DEG Twaddle, treatment lasting for 20--45 minutes. For very fine fibres, the strength of the solution or the time of immersion may be increased, e.g. a solution of 4 DEG Twaddle may be employed for 60 minutes. The solution may be circulated and the fibres may be conveyed in countercurrent thereto. Washing may consist of immersion in running water for about 30 minutes and may be effected in a similar manner to the alkaline treatment. The fibres are then dried and brushed. The treated fibres may be subjected to the action of a mechanical softening machine, to split them into still finer fibres. The treatment makes the fibres more absorbent. Specification 383,627, [Group IX], is referred to.