Toyo Seikan Kaisha, Ltd.

Minoru Mitsuhashi

Nobuyuki Sato

Seishichi Kobayashi

Kazuhisa Ishibashi

Hiroshi Matsubayashi

Kenji Matsuno

Muneki Yamada

Kiyoshi Kawaguchi

Nobuyuki Kato

Akira Sakamoto

Fumio Kanou

A process for manufacturing the butt-welded cans comprises the steps of applying a 0.5 to 3.5 .mu.m thick organic resin film for preventing the adhesion of melted metal particles to at least a 1-mm-wide region from the butt-weld portion edge of at least the inner surface of a steel plate can blank, and butt-welding the edges of the can blank by the use of a laser, or alternatively applying a 0.5 to 7.0.mu.m thick organic resin film, butting the edges of the can blank, and laser-welding the butted edges while a cooling device is brought into contact with the butted edges from the inner side of each can. In this case, it is preferred that the coating material having high thermal decomposition resistance is applied to the whole outer surface of each can, and the weld portion is then butt-welded by means of a CO.sub.2 laser. The aforesaid coating material have the high resistance to thermal decomposition and is the material in which the temperature at which a thermogravimetric weight reduction ratio of the coating material reaches 50% is 470.degree. C. or more, i.e., the coating material comprising a phenolic resin or fluoride resin, or a coating material containing a polyorganosiloxane, metallic oxide or metallic powder.

Butt-welded cans and process for manufacturing the same

There is here provided butt-welded cans made of steel plates having a carbon concentration of 0.02 to 0.09% by weight, the aforesaid butt-welded cans being characterized in that a coating film for preventing the adhesion of melted metal particles is applied to at least the inner surface of the weld portion and its vicinity of each can, and a carbon concentration index I of the weld portion satisfies the formula (1)

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.

Method of making a plastic hollow article

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Yokohama, Japan

Minoru Mitsuhashi