| 摘要 |
<p>PURPOSE: To make each thickness ratio of both hard and soft plastics alterable at discretion in a multilayer parison by molding a bend highish in the thickness ratio of soft plastics out of this plastic conduit formed with a single multilayer parison, and the other parts of hard plastics highish at the thickness ratio different in terms of synthetic resin type. CONSTITUTION: This method makes up an automobile air-conditioning duct tube B or a kind of plastic conduits with both bellows and joint parts as a bend by means of two layers superposed on each other in making hard synthetic resin Gas an outer layer, and soft synthetic resin F as an inner layer. In consequence, in a multilayer parison, each thickness ratio of the hard synthetic resin G and the soft synthetic resin F is freely alterable, and thereby, in time of assembling, each position of both ends of the plastic tube is largely decentered in a three-dimensional manner and assembled, and even in the case where there is necessary for piping, the bend is more apt to bend than the other parts, so in a state of being sufficiently curved, operations of mounting the plastic tube and piping work can be done easily.</p> |
