HEATING METHOD FOR PLASTIC EXTRUSION DIE, PLASTIC EXTRUSION DIE, AND EXTRUDER

摘要

PPROBLEM TO BE SOLVED: To provide a heating method for a plastic extrusion dies, which can adequately enhance heating efficiency around nozzles, the plastic extrusion dies, and an extruder. PSOLUTION: In this heating method for the plastic extrusion dies, a coil (C) is provided in such a manner as to surround a mouthpiece part (25) which is provided with the many nozzles (P); an eddy current is induced to the mouthpiece part (25) by passing an alternating current through the coil (C); and the mouthpiece part (25) is heated by Joule heat. Characteristically, a lining layer (Z) of a metallic material, which has a higher magnetic permeability than the mouthpiece part (25), is provided on the surface, on the side of the coil (C), of the mouthpiece part (25), so that the heating efficiency can be enhanced. PCOPYRIGHT: (C)2004,JPO