Bayer Aktiengesellschaft

Gunter Haladuda

Wolfram Wagner

Peter R Nyssen

Dirk Berkenhaus

Hans-Theo Van Pey

Gunter Espanion

Karl-Heinz Schott

Filaments of a molten material issue from a plurality of openings in a heated melt crucible and are further fiberized in a draw nozzle by means of a blowing medium. The diameter of the outlet openings (3) at the base of the melt crucible (1) is very small and is 0.2 to 1.5 mm, so that very fine primary filaments (12) are already formed at this point. These primary filaments are grasped by a very turbulent current at the entrance of the draw nozzle (5). The transverse component of the current decreasing in favor of the longitudinal component as the axial distance from the outlet openings (3) increases. The draw nozzle also has an inlet portion, which has a sharp outer edge and widens in the direction of flow, so that air blows against the primary filaments at a high speed and they are exposed to a strong pressure gradient in the longitudinal direction before entering the inlet portion. In the draw nozzle the primary filaments which are themselves already very thin are drawn out further until they have the required final diameter. For this purpose a zone is provided in the interior of the nozzle, following the inlet portion, in which zone the rate of flow of the blowing medium is 400 m/s to 600 m/s at a pressure of between 0.1 and 0.4 bar. By means of this device very fine mineral fibres with a substantially uniform fibre diameter of between 0.1 .mu.m and 5 .mu.m can be produced.

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Burscheid, Germany

Gunter Haladuda