HOLLOW ARTICLE MADE OF THERMOPLASTIC RESIN, MANUFACTURING METHOD OF THE HOLLOW ARTICLE, AND MANUFACTURING APPARATUS OF THE HOLLOW ARTICLE

摘要

A hollow article made of a thermoplastic resin and having both end portions whose wall thickness changes multidirectionally with high accuracy. The hollow article is formed by bringing a cavity of a drawing unit into contact with an outlet gap of an annular orifice nozzle (including an upwardly and downwardly movable core). A nozzle mouthpiece concentrically surrounds the core to form the outlet gap (having a variable gap width). Thermoplastic resin is injected into the cavity through the outlet gap to form one end portion. A tubular parison is drawn and formed while moving the drawing unit apart from the annular orifice. The tubular parison is blow-molded to form the hollow article body. The other end of the hollow article is injection-molded to the desired shape (such as a tri-port CV-joint boot for use in automobiles).