Patent GB-529510-A (GB)
Title: Improvements in or relating to the production of artificial filaments, threads, films and the like
IPC: D01D1/04
Filed: 1939-05-16
Abstract: 529,510. Artificial filaments, films &c DREYFUS, H. May 16, 1939, No. 14610. [Classes 2 (ii) and 2 (iii)] Artificial filaments, threads, foils, films, and similar shaped articles are obtained by bringing, by heat to a fused or plastic condition, a fusible fibre- or film-forming substance, or a composition containing it, extruding through orifices of appropriate shape under pressure applied directly to the substance by a heated inert liquid or vapour, and then solidifying the extruded articles. Setting may be effected by a liquid non-solvent medium and this may contain some solvent or softening agent, or setting may be effected by a gas or vapour, e.g. air or steam. The extruded articles may be subjected to a rapid temperature drop shortly after leaving the orifices or they may be subjected for a short time before setting to the action of a gaseous or vaporous medium of such composition and at such a temperature and pressure that any tendency to rapid change in the composition or physical state of the articles is reduced. The molten or plastic substance may contain a plasticizer. The extruded articles may be stretched during their passage from the orifices. The fusible substance may be cellulose acetate or other cellulose ester, mixed ester, ether or ether-ester. It may be a polyvinyl ester or ether, a polyacrylic, or polymethacrylic ester, or a polymer obtainable by condensation of bi-functional reagents, e.g. polyamides including those from amino-carboxylic or amino-sulphonic acids. Pressure may be applied to the fused substance by means of water, amyl alcohol or other alcohol, ethers such as anisol, dinaphthyl ethers, diphenyl ethers, or dimethyl ether of triethylene glycol. Aromatic or aliphatic hydrocarbons including hydrogenated aromatic hydrocarbons and halogen derivatives of hydrocarbons may be used. These agents may be solid or liquid at ordinary temperatures, but they must be fluid at a temperature below that of the intended extrusion temperature. Pressure may be applied by steam or an organic vapour. Apparatus for forming filaments may compirse a vessel 1 provided with several tubular elements 2, each carrying metal gauze 3 and spinnerets 4. Tubes 9 and 10 allow for introducing and withdrawing liquids or vapours. A stirrer 15 comprises a hollow shaft 18, stirrer arms 19, and a conveyer screw 20. The screw tends to cause liquids to rise while the stirrer arms are preferably sloped so as to cause liquids to sink. Coils 21 heat the stirrer by means of alternating current. The casing of vessel 1 may be lagged and may be heated electrically. The heating of the apparatus may be controlled by the thermostatic device 14. In operation the vessel is filled with hydrocarbon liquid. Fused filament-forming liquid is introduced through pipe 9, the displaced hydrocarbon flowing out through pipe 10. Valve 12 is closed and pressure is applied through a vessel of hydrocarbon communicating with vessel 1 through pipe 9, this pressure acting on the filament forming liquid and forcing it through the spinnerets. Fused cellulose acetate filaments may be received in an atmosphere of wet steam and then set by means of a cool liquid non-solvent, e.g. caustic soda solution, salt solutions, or aqueous alcohol. Plasticizers for cellulose acetate which may be used include acetins, phenols, phosphates, phthalates, tartrates, and sulphonamides. For polyamides there may be used as plasticizers, phenols, acetamide, benzamide, other amides, sulphonamides, acetic acid, glycollic acid, lactic acid, or formic acid. Uniform distribution of plasticizer may be effected in the manner described in Specifications 354,860, [Group V], or 476,638 or by other means. The shaped materials may be subjected to stretching after a re-softening step. They may be stretched in hot water or steam. They may be subjected to shrinking operations, esterification, twisting, stapling, crinkling, and other treatments. They may be coalesced to form unitary products suitable for use as bristles. Specifications 317,025, 317,026, [both in Class 120 (iii)], 357,565, 384,335, 394,702, 409,519, 484,192, fall in Group IX], 523,425, 523,774 and 524,897, also are referred to.