Nippon Steel Corporation

Mitsui Chemicals, Inc.

Mitsui Petrochemical Industries, Ltd.

Mitsui Takeda Chemicals, Inc.

Ryousuke Wake

Ryoichi Yoshihara

Hiroji Niimi

Takashi Hiraoka

Yoshihiro Kaneda

Masahiro Fuda

Minoru Kitayama

Yoichiro Mori

Tsutomu Tawa

Takao Saito

Makoto Yamasaki

Kazuya Ezure

Chikako Kouda

Fumiaki Hirata

A method of producing a resin-coated steel sheet for drawn-and-ironed cans. The resin-coated steel sheet has a steel sheet with a tin-coat on each side and a resin layer of a first crystalline thermoplastic polyester resin on one of the tin-coats and a second non-crystalline thermoplastic polyester resin on the first crystalline thermoplastic polyester resin. The first crystalline thermoplastic polyester resin has an alloying ratio of: 50.ltoreq.alloying ratio&lt;100. The second non-crystalline thermoplastic polyester resin has an alloying ratio of 0&lt;alloying ratio&lt;50. The method includes thermal fusion of a mixture of 95-5 percent by weight of a crystalline polyester resin and 5-95 percent of a non-crystalline polyester resin to produce the first crystalline thermoplastic polyester resin and the second non-crystalline thermoplastic polyester resin. The first crystalline thermoplastic polyester resin and the second non-crystalline thermoplastic polyester resin are coated onto the tin-coated steel sheet using two-layer extrusion T-die and then cooled quickly.

Method for manufacturing a resin-coated steel sheet for drawn-and-ironed

A resin-coated steel sheet for drawn-and-ironed cans and a method of producing the resin-coated steel sheet. The resin-coated steel sheet has a steel sheet with a tin-coat on each side and a resin layer of a first crystalline thermoplastic polyester resin on one of the tin-coats and a second non-crystalline thermoplastic polyester resin on the first crystalline thermoplastic polyester resin. The first crystalline thermoplastic polyester resin has an alloying ratio of: 50.ltoreq.alloying ratio &lt;100. The second non-crystalline thermoplastic polyester resin has an alloying ratio of 0&lt;alloying ratio &lt;50. The method includes thermal fusion of a mixture of 95-5 percent by weight of a crystalline polyester resin and 5-95 percent of a non-crystalline polyester resin to produce the first crystalline thermoplastic polyester resin and the second non-crystalline thermoplastic polyester resin. The first crystalline thermoplastic polyester resin and the second non-crystalline thermoplastic polyester resin are coated onto the tin-coated steel sheet using two-layer extrusion T-die and then cooled quickly.

Resin-coated steel sheet for drawn-and-ironed cans and drawn-and-ironed

A surface-treated steel sheet is provided, at a low cost, which has high weldability and is useful for a material of containers of foods and beverages. The surface treatment is conducted by applying flattened granular tin coating deposits having a specified diameter and high adhesion on a steel sheet surface at a specified plated area ratio, and applying thereon a metallic chromium coating and a chromium hydrate oxide coating. In the surface treatment, firstly, the surface of a steel sheet is subjected to tin-plating in an acidic tin plating bath containing a conventionally used brightener in an amount of from 0,001 to 0.05 g/l so as to form flattened granular tin coating deposits having a diameter of 0.4-2.4 .mu. at a plated area ratio of 5 to 30% and to improve the adhesion to the steel sheet and decrease falling-off of the granular tin coating deposits until completion of chrome-plating, thereby the variation of the amount of tin coating being decreased. Subsequently, the sheet is plated with metallic chromium in an amount of 50-150 mg/m.sup.2, and further chromium hydrate oxide layer is formed in an amount of 2-40 mg/m.sup.2 as chromium. Thus a surface-treated steel sheet, which has satisfactory surface appearance, paint adhesiveness, under-paint-coating corrosion resistance of conventional tin-free steel sheets, and stable weldability, is producible at a low cost.

Process for producing surface-treated steel sheet superior in

A surface-treated steel sheet is provided, at a low cost, which has high weldability and is useful for a material of containers of foods and beverages. The surface treatment is conducted by applying flattened granular tin coating deposits having a specified diameter and high adhesion on a steel sheet surface at a specified plated area ratio, and applying thereon a metallic chromium coating and a chromium hydrate oxide coating. In the surface treatment, firstly, the surface of a steel sheet is subjected to tin-plating in an acidic tin plating bath containing a conventionally used brightener in an amount of from 0.001 to 0.05 g/1 so as to form flattened granular tin coating deposits having a diameter of 0.4-2.4 .mu. at a plated area ratio of 5 to 30% and to improve the adhesion to the steel sheet and decrease falling-off of the granular tin coating deposits until completion of chrome-plating, thereby the variation of the amount of tin coating being decreased. Subsequently, the sheet is plated with metallic chromium in an amount of 50-150 mg/m.sup.2, and further chromium hydrate oxide layer is formed in an amount of 2-40 mg/m.sup.2 as chromium. Thus a surface-treated steel sheet, which has satisfactory surface appearance, paint adhesiveness, under-paint-coating corrosion resistance of conventional tin-free steel sheets, and stable weldability, is producible at a low cost.

Surface treated steel sheets having excellent rust resistance and weldability, suitable for manufacturing various kinds of cans, produced by a process comprising applying 0.2 to 1 g/m.sup.2 of tin coating on a surface of a nickel coated cold rolled steel sheet, applying 0.01 to 0.3 g/m.sup.2 of zinc coating on the tin coating in such an amount that the ratio of the zinc coating amount to the tin coating amount is in a range from 2 to 30% by weight, and heating the coatings to alloy substantially all of the zinc into the tin coating layer with substantially no non-alloyed zinc left on the tin coating.

Thinly tin coated steel sheets having excellent rust resistance and

A method for the electrolytic tinning of steel strip in an electrolytic bath wherein the steel strip is the cathode and insoluble anodes are used, the electrodes are immersed in an electrolyte solution containing tin ions and wherein the concentration of the tin ions in the bath is controlled by passing the solution exterior of the bath in contact with tin in particulate form, while simultaneously maintaining a high content of dissolved oxygen in the solution. This latter treatment replenishes the tin concentration of the solution and the thus replenished electrolytic solution can be returned to the bath in a manner so as to consistently maintain the tin ion concentration at the desired level.

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Himeji, Japan

Ryousuke Wake