| 摘要 |
549,208. Artificial filaments, films &c. DU PONT DE NEMOURS & CO., E. I. May 5, 1941, No. 5801. Convention date, May 4, 1940. [Class 2 (ii)] [Also in Groups V and X] In a process for the melt-spinning of organic filament- or film-forming compositions, discrete particles of the solid material are fed from a supply to a melting zone through a passage which prevents the solid material from coming into contact with any portion of the apparatus having a temperature at or above that at which the material melts or appreciably softens until the material has reached the melting zone. The melt-spinning apparatus includes a melting chamber, a heated melting grid in the chamber, and a hopper, constructed to move progressively a body of discrete particles of the composition into the melting chamber, and separated therefrom by insulating means. As shown in Fig. 1, a hopper 11 is filled or partly filled with flakes or chips of a solid filament-forming composition 12. The flakes fall on to a melting grid 15 which may be heated by passage therethrough of hot vapour. The grid 15 is mounted above the heated chamber 18 which may be heated by vapours passing through coils 19. The filament-forming composition melts and drains from the grid into melt chamber 20 whence it may be removed and forced through an extrusion device and collected in the form of filaments, yarns, sheets, ribbons, or the like, or applied directly as coatings on metal wires or other objects. The hopper is thermally insulated from the melting grid 15, and the heated chamber 18 by means of the insulation 24. The solid filament-forming composition is prevented from contacting with the insulation 24 by means of the confining skirt 25. In the modified apparatus shown in Fig. 2, the insulating ring 24 is lined with a thin metal sheet 26. This prevents contamination of the composition as a result of disintegration of the insulating material 24. The metal sheet 26 also helps to keep the assembly gas-tight. It may be made of stainless steel. The skirt 25 may be spaced from the wall 26 or insulated from it by an insulating material. The process may be applied to the melt extrusion of synthetic linear fibre-forming polymers, e.g. polyamides. The composition may be pre-heated before contacting the metal grid 15, provided that it is not heated to or above its melting point. Specifications 461,236, 461,237, and 533,307, are referred to. The Specification as open to inspection under Sect. 91 is not restricted to melt spinning operations but relates in general to the feeding of the compositions to a melting zone. This subject-matter does not appear in the Specification as accepted. |
