GB340930A - Improvements in or relating to the manufacture of artificial filaments or threads - Google Patents

Abstract

Apparatus for making filaments; cellulose carboxylates and ethers.-Relates to the production of artificial filaments and threads by extruding a solution of cellulose acetate &c. into an evaporative atmosphere and consists in passing the filaments after the formation of a skin-like outer layer thereon into an atmosphere of solvent or other vapour to soften said outer layer and applying a tension to stretch the filaments such tension being wholly or partially confined to that portion of the filaments which has been submitted to the softening influence of the vapour. Strong filaments of fine or extremely fine denier may be produced. As shown, filaments 8 are extruded from a line jet 7 into a spinning cell 9, passing thence through a softening chamber 16 and a drying chamber 30 to a cap spinning device 40; in a manner similar to that described in Specification 340,929. To confine the stretch substantially to the portion of the filaments within the chamber 16, a gate tension device 44 is provided near the bottom of the cell 9. On starting up, the gate is opened and the thread <PICT:0340930/IV/1> is fed over a smaller diameter roller 36 to impart little or no stretch. Afterwards, the guide 39 is moved to direct the filaments over a conical portion 37 on to a larger diameter 38 and impart stretch, the gate 44 being simultaneously closed through levers 41, 42 and arm 43. The gate 44 may be replaced by a roller which may rotate at a speed equal to or greater than the speed of extrusion so that the filaments may be stretched in the cell 9. To facilitate stretching, plastifiers or high boiling solvents may be added to the spinning solution; thus for cellulose acetate, high boiling solvents such as cyclobutanone, acetyl acetone, diacetone alcohol, dimethyl ethylene glycol, monomethyl or monoethyl ethylene glycols; plasticizers such as methyl or ethyl xylene sulphonamides, or mixtures thereof may be added to the spinning solutions. Cellulose derivatives include cellulose formate, acetate, propionate and butyrate; methyl, ethyl or benzyl cellulose; or the condensation products of cellulose and glycols and other polyhydric alcohols. Specifications 165,519, 198,023, 203,092, 277,089, 300,998, 323,790 and 325,233, [all in Class 2 (ii), Cellulose &c.], also are referred to.