Patent GB-453869-A (GB)
Title: Improvements in the manufacture of artificial filaments, ribbons, films and like materials
IPC: D01F2/30
Filed: 1935-03-20
Abstract: <PICT:0453869/IV/1> <PICT:0453869/IV/2> Filaments, threads, ribbons, foils, films, and like materials are obtained by spinning a solution of an organic thermoplastic filament- or filmforming substance and during the spinning operation subjecting the materials while still containing a substantial quantity of volatile solvent to the action of steam under pressure at above 100 DEG  C.  The spinning solution containing a volatile solvent may be extruded into steam under pressure at above 100 DEG  C., or it may be extruded into heated air preferably under pressure and before the solvent is removed the filaments or films are carried into a space containing the steam. The products may be subjected to stretching during the spinning operation, and the tension may be wholly or partly prevented from acting on the materials immediately upon extrusion from the nozzles. The steam may be wet or saturated, and at 110--135 DEG  C. under a pressure of 10--30 pounds or more per square inch above atmospheric pressure. The steam may contain acetone, dioxane or other solvent vapours. Spinning may be started in air at atmospheric pressure, the air being replaced by steam after spinning has begun.  The process is applicable to the production of filaments or films of cellulose esters such as the acetate, formate, propionate, butyrate, and nitro-acetate, or cellulose ethers such as methyl, ethyl, or benzyl ethers, or polyvinyl compounds such as polyvinyl acetate. Hollow filaments may be obtained by using steam at temperatures 30 DEG  C. or more above the boiling point of the solvent of the spinning solution.  As shown in Fig. 1, filaments 7 extruded from jet 6 pass down the cell 8 inside a casing 9, and leave through a perforation in a plate 10, thence to a godet 11 and cap spinner 12.  Steam is supplied to the cell by valved pipes 14 and annular pipes 16.  A pipe 17 withdraws steam and solvent vapours.  The cell also has a pressure gauge 20, relief valve 21 and valved drain pipe 19.  Heating pipes 22 are provided.  The top of the cell is provided with a hood 23 which is raised when starting the spinning but screwed down to make a tight joint with pad 24 when the filaments have started to wind on the device 12.  A current of air drawn through the cell by the suction device 34 assists filament formation when starting the operation.  As shown in Fig. 2, the spinning solution passing through the filter-candle 5 is heated by coil 41.  A perforated plate 42 is provided between the parts 36, 37 of the cell.  Compressed air is supplied through inlet 43.  Steam under pressure is supplied through pipe 13. Steam and solvent are removed through pipe 17 and air and solvent are removed through pipe 34.  In examples, cellulose acetate in dioxane, or monomethyl ether of ethylene glycol with or without acetone or methyl glycol mono-acetate is spun into filaments in the apparatus described above, the temperature of the steam being 120--135 DEG  C. and the steam being just wet.  Specification 320,632, [Class 2 (ii)], is referred to.  The Provisional Specification refers to Specification 397,509.