| 摘要 |
PURPOSE:To manufacture a closed hollow body simply by a method wherein a parison with the bottom thereof closed is arranged between dies as separately opposed to each other and closed grasped with a peripheral projection so that it is formed into a cavity with a higher internal pressure as the dies are clamped. CONSTITUTION:A thermoplastic resin is fed hanging between dies 1a and 1b as separately opposed to each other from an extrusion dies 2 as a parison 3. Then, when the dies 1a and 1b begins to be clamped, the bottom of the parison 3 is closed. The parison 3 is preblown with air blown in from a hole formed in the extrusion die 2. As the dies are clamped, peripheral projections 5a and 5b are inserted into the dies so that the parison 3 is pressed in contact with die cavities 4a and 4b and molded along the cavities 4a and 4b with the pressure therein 3 going up above 1atom. Then, the molding is cooled to harden and the dies are opened. After the removal of excessive flash, a closed hollow body is obtained with the internal pressure exceeding 1atom. It is used for floats, buoys, packing cushions and the like. |
