| 摘要 |
<p>Method and apparatus are provided for producing a filament from molten rapidly crystallizing filament-forming thermoplastic polymers. The apparatus includes a chamber for the molten crystallizable polymer. Heating means are associated with the chamber for melting the polymer and for maintaining the polymer in a molten condition. An electrically conductive material is disposed at one end of the chamber, the electrically conductive member including an orifice formed therethrough. Controllable means are provided for applying a preselected controlled pressure to the molten polymer, the controlled pressure being sufficient to form a static flat meniscus of the molten polymer at the orifice, but being insufficient to extrude the molten polymer through the orifice. An apertured plate, which is formed of electrically conductive material, is disposed at a predetermined distance from the orifice, the aperture in the plate and the orifice being aligned. Finally, means are provided which electrically connect one pole of a D.C. power supply to the electrically conductive material through which the orifice is formed, and which connect the other pole of the D.C. power supply to the apertured plate. In this way, an electronic static field is created between the orifice and the apertured plate. The value of the applied voltage is large enough to overcome the static flat meniscus at the orifice and to form a cone terminating in a molten polymer jet, but is insufficient to generate an electrical discharge between the orifice and the apertured plate. Above that certain critical field strength, the flat meniscus at the orifice is deformed into a conical shape from which a fine continuous jet of molten polymer is drawn. Subsequent crystallization of this jet yields a continuous filament which can be drawn or otherwise treated in separate finishing operations so as to optimize its properties. Thus, the high pressure extrusion used in the past to form filaments is obviated.</p> |
