GB476431A - Manufacture of artificial threads - Google Patents

Abstract

Artificial fibres containing nitrogen and sulphur and capable of being dyed with wool dyestuffs, are prepared by spinning a solution of viscose and treating the spun fibres, while they still contain free xanthate groups, with ethylene imine, or homologue thereof, or other analogous cyclic nitrogen base. The imine may be used as a free base or as a salt, and either in vapour, liquid, or dissolved condition, and may be used in sufficient quantity or not to react with all the free xanthate groups in the filaments. Any xanthate groups which still remain may be split off by treatment in an acid bath. The spinning baths used for the viscose may contain up to 100 per cent of sulphuric acid, and in the case of the stronger baths the retention of the necessary number of xanthate groups is obtained by shortening the length of the bath, by inserting a washing bath, or by avoiding long stretches in air before treatment with the cyclic base. The following examples are given: (1) normal viscose is spun into a saturated solution of sodium sulphate containing 4,2 per cent of sulphuric acid, washed in sodium sulphate solution, and passed through ethylene-imine vapour; (2) viscose containing 50 xanthate groups per 100 cellulose molecules is spun into ammonium sulphate solution and the threads passed through a solution of N-methylethylene-imine; (3) viscose having 45 xanthate groups per 100 of cellulose is spun as in (2) and the threads are passed through a gutter into which flow aqueous acetic acid and aqueous ethylene-imine. After heating for 10 secs. at 75 DEG C., the threads are passed into aqueous sulphuric acid to eliminate residual xanthate groups; (4) viscose containing 55 xanthate groups per 100 of cellulose is spun into a bath containing sodium sulphate and sulphuric acid and the threads are washed and passed through aqueous ethylene-imine; (5) viscose containing 35 xanthate groups per 100 of cellulose is spun into a bath containing sulphuric acid and ammonium sulphate and the threads are led into aqueous ethylene-imine; (6) fresh viscose containing 60 xanthate groups per 100 of cellulose is spun into a bath containing sodium sulphate, sulphuric acid, and the condensation product from formaldehyde and naphthalene sulphuric acid. The threads are passed through aqueous sodium sulphate solution and led into a solution containing ethylene-imine and acetic acid; (7) a viscose containing 54 xanthate groups per 100 of cellulose is spun into a bath made by esterifying sulphuric acid with methanol. The thread is passed through water and then into a solution of ethyleneimine semi-neutralized with acetic acid; (8) the same viscose as in (7) is spun into 74 per cent sulphuric acid and the threads are passed through water, air, and then ethylene-imine as in (7); (9) the same viscose as in (7) and (8) is spun into a bath containing sulphuric acid, ammonium sulphate, and sodium sulphate, and the threads are passed through water, air, and ethylene-imine as in (7) and (8).