Dry spinning

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The dry-spinning is solution spinning process in which the filament is effected by that the hot solution of polymer and solvent in a heated spinning chimney is extruded (diameter 150 to 300 mm. Length of 2000 to 8000 mm) in a hot gas stream, wherein the organic solvent of the rays of the spinning solution evaporate after their exit from the spinneret and the thread passes through the gel form into the solid phase due to the loss of solvent. In order to be able to catch the evaporating solvent almost completely, the thread formation process takes place in closed spinning shafts.

The exact spinning conditions with regard to concentration, viscosity, temperatures, amounts of spinning gas etc. are polymer and solvent-specific. Filament take-off speeds of 300 to 400 m / min are common, but in processes with rapid evaporation of the solvent in a vacuum and rapid thread solidification, up to 5000 m / min are also possible.

If both the dry spinning process and the wet spinning process can be used for the same polymer, the dry spinning process has the following advantages:

  • a higher polymer concentration can be processed, which is why the plant performance is higher;
  • higher spinning speeds are possible;
  • there is usually no need to wash and dry the spared threads.

The first artificial silk (Chardonnet silk) was already produced at the beginning of the 20th century using the dry spinning process. This was followed by the production of cellulose acetate filaments in the early 1920s and various PVC fibers . In 1946, the DuPont company began producing PAN fibers . Dry spinning is also used commercially today for fibers made from PVA , PAN copolymers, PUR and aromatic polyamides .

See also

Individual evidence

  1. ↑ Zakhar Aleksandrovič Rogowin: Man-made fibers: chemistry - technology. Georg Thieme Verlag, Stuttgart / New York 1982, ISBN 3-13-609501-4 , p. 18.
  2. ↑ Franz Fourné: Synthetic fibers: production, machinery, Features: Manual for system planning, machine design and operation. Carl Hanser Verlag, Munich / Vienna 1995, ISBN 3-446-16058-2 , p. 489.
  3. ^ MD Lechner, K. Gehrke, EH Nordmeier: Makromolekulare Chemie. A textbook for chemists, physicists, materials scientists and process engineers. Springer Verlag, Berlin / Heidelberg 2014, ISBN 978-3-642-41768-9 , p. 638.
  4. ↑ Franz Fourné: Synthetic fibers: production, machinery, Features: Manual for system planning, machine design and operation. Carl Hanser Verlag, Munich / Vienna 1995, ISBN 3-446-16058-2 , p. 490.
  5. ^ MD Lechner, K. Gehrke, EH Nordmeier: Makromolekulare Chemie. A textbook for chemists, physicists, materials scientists and process engineers. Springer Verlag, Berlin / Heidelberg 2014, ISBN 978-3-642-41768-9 , p. 639.
  6. ↑ Zakhar Aleksandrovič Rogowin: Man-made fibers: chemistry - technology. Georg Thieme Verlag, Stuttgart / New York 1982, ISBN 3-13-609501-4 , p. 19.