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US 9,283,697 B2Granted
Stretched and foamed plastic container and method of producing the same
AssigneeToyo Seikan Kaisha, Ltd.
InventorsKentarou Ichikawa, Nobuhisa Koiso, Norio Akuzawa
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Abstract
A foamed plastic container in which the cell diameters vary along a gradient so as not to decrease the content protection performance, in a manner quite different from the foamed cells distributed in the conventional foamed containers. The foamed plastic container has a container wall formed by using a plastic material and in which foamed cells are distributed, the lengths of the foamed cells in the surface direction of the container wall decreasing from the outer surface of the container toward the inner surface thereof.
Claims7
A method of forming a foamed preform including:
- forming a non-foamed preform by injecting and filling a molten resin imbibing an inert gas in a mold cavity while applying hold pressure in the mold cavity, and
- heating said non-foamed preform;
- wherein the hold pressure is set so that the weight reduction ratio is not larger than 5%, and
- the non-foamed preform is obtained by injecting and filling a molten resin imbibing an inert gas in a metal mold cavity maintaining the hold pressure therein, followed by solidification by cooling;
- wherein weight reduction ratio=((M0−M1)/M0)×100, where M0 is the weight of a preform obtained by injecting resin without imbibing inert gas under the conditions set so that molding defects such as sink mark will not occur, and M1 is the weight of the gas-imbibing preform obtained from the resin imbibing inert gas;
- and
- wherein the hold pressure is pressure caused directly by addition of the molten resin to the mold cavity.
4 more elements
Dependencies are inferred from the claim text.