| 摘要 |
<p>PURPOSE:To provide the subject method comprising the steps of : melting polyolefin and holding a parison after extrusion at least for more than five seconds thereby to obtain a hollow body free of fish skins and excellent in transparency and surface luster by use of an ordinary hollow molding machine. CONSTITUTION:Polyolefin of a melt index in the range of from 0.1-2 is molten. The temperature of the range of 190-260 deg.C. The molten resin is extruded as a parison through a die head by means of an accumulator. Thereafter, the molten resin is held for more than five seconds, preferably more than 20 seconds in a state where the temperature of the parison is more than the melting point of said polyolefin (preferable is a state of being clamped by metal molds). Then, a pressurized fluid is forced in said parison to form a hollow body. By carrying such holding operation, the temperature of the parison is gradually lowered. However, since it is not hardened, the molded vessel is improved remarkably in luster.</p> |
