GB654083A - Spinning of viscose - Google Patents

Abstract

Regenerated cellulose structures of improved physical properties are produced by spinning viscose containing at least one millimole per 100 grams of viscose of a mono-amine having at least four carbon atoms in the molecule, but containing in the molecule no radical having more than six carbon atoms, and being soluble in 6 per cent aqueous sodium hydroxide solution to the extent of at least 0.3 per cent, into an aqueous sulphuric acid spinning bath containing from 1 to 15 per cent zinc sulphate. The viscose preferably contains about 1-4 millimoles of an aliphatic or cyclo-aliphatic mono-amine per 100 grams of viscose, or 0.1-1.0 per cent of the amine. The cellulosic structures may be passed from the first into a second bath and stretched in the latter to at least 20 per cent. The coagulating bath preferably contains 4-12 per cent sulphuric acid, 13-25 per cent sodium sulphate, and 1-15 per cent zinc sulphate, optionally with about 1-5 per cent of ferrous sulphate. Alternatively the action of the zinc sulphate may be supplemented by other salts of divalent metals such as manganese sulphate or nickel sulphate, or by chromic sulphate. The viscose may contain 4-10 per cent cellulose combined as sodium cellulose xanthate with from 25-50 per cent carbon disulphide and 4-8 per cent of sodium hydroxide (based on recoverable bone dry cellulose). In an example aged alkali cellulose is xanthated using 35 per cent carbon disulphide (based on the recoverable bone-dry cellulose) and the product dissolved in an aqueous solution of sodium hydroxide containing triethanolamine, the proportions used being such as to give a viscose containing 7 per cent cellulose, having a total alkalinity of 6 per cent expressed as sodium hydroxide and containing 1.8 millimoles of the amine per 100 grams of viscose. The viscose in the unripened state is spun into yarn by extrusion into a primary coagulating and regenerating bath containing 6.0 per cent sulphuric acid, 14 per cent sodium sulphate and 15 per cent zinc sulphate. The filaments thus formed are stretched in a water bath at 95-100 DEG C. to give 80 per cent elongation, washed, processed and dried. Examples are also given using triethylamine, diethanolamine, butylmonoethanolamine, diethylaminoethanol, cyclohexylamine, and n-amylamine respectively. Amines which may be used in addition to those used in the examples are diethylamine, dipropylamine, butylamine, ethyldiethanolamine, dipropanolamine, propylpropanolamine, hexanolamine, amyldiethanolamine, butylmethylethanolamine, propylethanolamine, cyclohexylethanolamine, hexamethyleneimine, piperidine, pyridine, and hexyldiethanolamine. The secondary bath may consist of water, dilute (e.g. 1-3 per cent) sulphuric acid, or it may have the same composition as the coagulating bath but at a greater dilution, e.g. one-fourth the concentration of the coagulating bath. Specifications 533,309, 652,741 and U.S.A. Specifications 2,347,883, 2,347,884, and 2,364,273 are referred to.