摘要 |
A method for making a hollow shaped body from a thermoplastic resin by injection molding, which method comprises injecting an amount of molten resin sufficient for the preparation of the hollow shaped body from an injection nozzle into a mold through an injection aperture in said mold, injecting gas under pressure through said injection nozzle and aperture to expand and distribute the molten resin over the interior surfaces of the mold, whereby said hollow shaped body is formed within said mold with a gas-entry opening in said hollow shaped body, cooling the hollow shaped resin body so formed to a temperature beneath the softening point of the resin, opening the interior of the hollow shaped body to equalize the pressure therein with ambient pressure, and then opening said mold to remove said hollow shaped body. |