| 摘要 |
PURPOSE:To make it possible to mold a hollow product excellent in both external appearance and quality in a short time by a method wherein a parison is heated and pressurized by forcing high temperature liquid from an inlet pipe in the parison under the state that an outlet pipe is closed during molding and, after molding, low temperature liquid is fed from the inlet pipe so as to push out the waste steam in a mold. CONSTITUTION:After a polyethylene parison 6 is set in a mold 1, steam having a temperature of 120 deg.C is fed in the parison 6 under the state that the outlet pipe 7 of fluid so as to pressurize and at the same time heat the parison 6. As a result, the parison 6 is rapidly formed into a product 2 faithful to a cavity and, after that, the supply of steam from the inlet pipe 8 is changed over to the supply of air having a temperature of 15 deg.C and at the same time the outlet pipe 7 is opened. Consequently, the waste steam in the product 2 is rapidly displaced with supplied air and, since the displaced air flows in the product, the hardening of the product is accelerated and the time from demolding to the finish of the product can be made shorter than even and, in addition, the obtained product has good external appearance, stable quality and also large strength. |
