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US 4,225,553 AGranted
Method of manufacturing low-rigid, wrinkle-free articles
AssigneeToyo Seikan Kaisha, Ltd.
InventorsKazumi Hirota, Kikuo Matsuoka
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AssigneeToyo Seikan Kaisha, Ltd.
InventorsKazumi Hirota, Kikuo Matsuoka
Estimating the term…
A thin sheet having a low rigidity is drawn while being depressed over the radiused corner of a die by elastic force or hydrostatic force to obtain a formed article whose sidewall part and flange part have no wrinkles. The force is applied through an elastic rubber provided around the punch and having an outside diameter larger than the inside diameter of the die cavity, or through an annular rigid body on which elastic pressure or fluid pressure is exerted. The hardness of the rubber is preferably approximately 70 to 85 in accordance with ASTM D 2240 Durometer A. A laminate not more than about 200 .mu.m in thickness and consisting of a thermoplastic resin film, aluminum foil and a heat-sealable resin film is drawn into a formed article or a container which is light in weight and suitable for containing foods, for instance.
A method of manufacturing a formed article comprising the steps of
Dependencies are inferred from the claim text.