Toyo Seikan Kaisha, Ltd.

Fumio Kanou

Muneki Yamada

Kiyoshi Kawaguchi

Nobuyuki Kato

Akira Sakamoto

Minoru Mitsuhashi

The peripheral portion of a flat, molecularly orientable material stock of substantially uniform thickness having a temperature below the upper limit of the molecularly orientable temperatures of the plastic material is clamped, and the central portion of the plastic material stock is introduced into a die cavity while compressing the central portion with an upper plunger and a lower plunger, thereby forming a hollow preform having a sidewall portion made from the plastic material which has been forced out from between the upper plunger and the lower plunger, while the sidewall portion is kept in contact with the side surface of the upper plunger kept at about molecularly orientable temperature. Thereafter, while the upper plunger is returning, a fluid under pressure is supplied into the hollow preform to expand radially the sidewall portion, so that the sidewall portion is brought into contact with the inner surface of the die cavity kept at a temperature below the lower limit of the molecularly orientable temperatures for cooling and solidifying. Thus, the sidewall portion of a plastic hollow article is formed from the sidewall portion of the hollow preform, and a plastic hollow article having a flange portion, the sidewall portion which is molecularly oriented, and a bottom wall portion is made.

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Yokohama, Japan

Fumio Kanou