Method and apparatus for ultrasonically assisted melt extrusion of fibers

• Main Author: Jameson, Lee Kirby
• Format: Patent
• Language: English
• Published: 28.05.2002

The present invention relates to the melt extrusion of a thermoplastic polymer. An apparatus and a method for the melt extrusion of a molten thermoplastic polymer, e.g., as fibers and nonwoven webs, which apparatus and method utilize ultrasonic energy to assist in the melt-extrusion process. The apparatus includes a die housing which defines a chamber adapted to receive the molten thermoplastic polymer and a means for applying ultrasonic energy to a portion of the molten thermoplastic polymer. The die housing includes a chamber adapted to receive the molten thermoplastic polymer, an inlet orifice adapted to supply the chamber with the molten thermoplastic polymer, and an extrusion orifice adapted to receive the molten thermoplastic polymer from the chamber and extrude the polymer. The means for applying ultrasonic energy is located within the chamber. The method involves supplying a molten thermoplastic polymer and extruding the molten thermoplastic polymer through an extrusion orifice in the foregoing apparatus to form a threadline. The means for applying ultrasonic energy is at least partially surrounded by molten thermoplastic polymer and is adapted to apply the ultrasonic energy to molten thermoplastic polymer as it passes into the extrusion orifice. While extruding the molten thermoplastic polymer, the means for applying ultrasonic energy is excited with ultrasonic energy. The resulting threadline then is attenuated to form a fiber. The means for applying the ultrasonic energy may be an ultrasonic horn.