GB419918A - Manufacture of new staple fibre - Google Patents

Abstract

Artificial threads of regenerated cellulose are cut to form staple fibre and the cut threads are acylated under such conditions that their structure is retained and that they remain insoluble in organic solvents. The regenerated cellulose may be artificial silk from viscose, cuprammonium cellulose, denitrated nitro cellulose, or cellulose obtained by precipitation from solutions of cellulose in quaternary ammonium salts. The esterification may be conducted with the aid of an acid anhydride, or acid chloride, with or without movement of the cellulose material or acylating liquid, in presence or absence of an acid, alkaline, or neutral catalyst or solvent, and with or without preliminary swelling. The esterification may be carried to the mono-, di-, or tri-acidyl stage. The product has good electric and thermal insulating properties, and may be dyed with cellulose acetate dyestuffs. It may be spun or woven with other artificial fibres or with natural fibres. In examples cuprammonium or viscose threads are cut to stable length and impregnated with potassium or sodium acetate solution, dried, then acetylated with acetic anhydride in xylene, perchlorethylene, chlorbenzene, or petroleum. The product is centrifuged, dried, washed, and dried. In another example viscose staple fibres are benzoylated in the presence of pyridine. In another example viscose staple fibres are treated with acetic acid and then acetylated with acetic anhydride, acetic acid, and zinc chloride. Specifications 319,584, [Class 2 (ii)], 343,104, 353,978, and 379,658 are referred to. The Specification as open to inspection under Sect. 91 comprises also processes of esterifying artificial threads of regenerated cellulose and then cutting them to form staple fibre. In an example a bundle of viscose threads is conducted continuously from the spinnerets through the precipitation bath and subsequent treatment baths. Before the drying there is inserted an impregnating bath containing potassium acetate and an acylating bath containing acetic anhydride and perchlorethylene. The washed and dried material is cut to form staple fibre. This subject-matter does not appear in the Specification as accepted.