GB836762A - An improved process for the manufacture of threads, fibres and films from viscose, as well as the products thus obtained - Google Patents

Abstract

Artificial threads, films and like products are made by extruding into an acid spinbath containing at least 2% by weight of a soluble zinc salt, and preferably sulphuric acid, viscose containing an ethoxylated cation-active quaternary ammonium compound and a polyepoxy ethane in the relative proportions of 40-80% by weight of the former to 60-20% by weight of the latter. The cation-active compound has the general formula <FORM:0836762/IV (a)/1> where R1 and R2 represent preferably alkyl radicals, R1 preferably containing 6 or more carbon atoms and R2 preferably containing 1-3 carbon atoms; Z represents an anion such as hydroxide, halide, sulphate or acetate; x and y are whole numbers whose sum may be up to 50 or more; and n is 2-4. R1 may be derived from coconut oil or soya bean oil or may be octadecyl, n may be 2, x+y may be 2, 10 or 15 and Z may be chlorine. The proportion of cation-active compound in the viscose may be 0.5 to 5% by weight, based on the cellulose in the viscose, and the total proportion of cation-active compound plus polyepoxy ethane in the viscose is preferably at least 1% and may be over 2%. The molecular weight of the polyepoxy ethane is preferably 1500-4500. The zinc salt in the spinning bath is preferably zinc sulphate in the proportion of 3 to 5%. The sulphuric acid content of the spin bath is preferably below 7% by weight. The viscose preferably contains 5.5-8% of cellulose and 4-6% of sodium hydroxide and preferably has an ammonium chloride salt point of 10 to 18. After being withdrawn from the spin bath the threads may be stretched in excess of 50% in a weakly acidic second bath at a temperature above 80 DEG C. In an example, viscose containing 7.5% of cellulose, 5.7% of sodium hydroxide, 36% of carbon bisulphide (based on the cellulose), 1% (based on the cellulose) of a cation-active compound in which R1 is a saturated straight chain hydrocarbon radical containing 8-18 carbon atoms, R2 is methyl, n is 2, x+y=15 and Z is chlorine, and 1% (based on cellulose) of a polyexpoxy ethane having an average molecular weight of about 4000, is spun at a salt-point of 14-16 into an aqueous spin bath at 65 DEG C. containing 4.8% by weight of sulphuric acid, 12% of sodium sulphate and 3.5% of zinc sulphate. Threads produced according to the invention have a total skin character and are improved with respect to retention of tensile strength after plying to form tyre cord.