Bayer Aktiengesellschaft

Rolf B Hirsch

Ulrich Reinehr

Hermann-Josef Jungverdorben

Gunter Turck

A process for dry spinning of synthetic polymers, in particular PAN threads containing more than 85 wt. % acrylonitrile in the PAN (co)polymer, with high spinning chimney capacities of at least 20 kg PAN solid per spinning chimney and hour, using superheated steam as the spinning gas and with in-chimney finishing with water or aqueous finishes.

Pan dry spinning process of increased spinning chimney capacity using

A process for the dry spinning of synthetic polymers, in particular polyacylonitrile fibres, from solutions in high polar solvents, such as dimethylformamide, which are heated to 100.degree.-150.degree. C. shortly upstream of the spinneret and spun there by spinnerets having a certain shape, and in the spinning cell the specific energy supply is at least 0.090 kWh per m.sup.2 of heated cell area, the cell is charged with at least 70 m.sup.3 (S.T.P.) of hot air per hour, and the filaments are treated in the lower part of the cell with water or aqueous preparations, so that the temperature of the filaments which leave the cell is decreased below 110.degree. C. Under these conditions, the unexpectedly high spinning cell outputs of at least 20 kg of PAN solid per spinning cell per hour can be achieved without yellowing or self-ignition of the filaments occurring.

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Dormagen, Germany

Rolf B Hirsch