Toyo Seikan Kaisha, Ltd.

Toyo Seikan Group Holdings, Ltd.

Tomomi Kobayashi

Katsuhiro Imazu

Akira Kobayashi

Nobuyuki Sato

Masao Ishinabe

Hisao Iwamoto

Imazu Katsuhiro

Kazuhiro Sato

Hiroshi Fujimoto

Masanori Aizawa

Ikuo Komatsu

Takeshi Aihara

Naoya Matsumoto

Akihiko Machii

Norihito Saiki

Naoto Watanabe

Norihiko Saiki

Provided is a polygonal in which a decoration effect equivalent to that of a cylindrical base-can is obtained without causing folding or deformation in a can body-part. Bottom-part outer-peripheral parts (A-) of a cylindrical base-can that are expected to form linear parts (B-) of a polygonal can (B) are moved inward in a radial direction, while bottom-part outer-peripheral parts (A-) of the cylindrical base-can that are expected to form corner parts (B-) of the polygonal can are moved outward in the radial direction. Thus, the polygonal can is molded such that the body-part cross-section peripheral length of the cylindrical base-can and the body-part cross-section peripheral length of the molded polygonal can have a substantially isometric relationship.

Polygonal can and method for forming thereof

A shock resistant seamless can comprising a side wall having an inside surface and an outside surface formed from a laminate of a metal substrate and a thermoplastic resin layer provided on the inside surface of the can side wall, wherein the inner surface of the side wall resin layer opposite the metal substrate comprises a plurality of dotted projections.

Seamless can and process for making the same

A method of producing seamless cans wherein a blank holder 2 is inserted in a metal cup 5 coated with an organic film 12, a punch 1 is advanced into a cavity 7 in a die 3 while pushing the bottom 5a of the metal cup onto the flat surface portion 3a of the die by the blank holder 2, so that the side wall 5b of the metal cup 5 is brought into intimate contact with the flat surface portion 3a of the die and with the working corner 3b having a small radius of curvature, thereby to reduce the thickness of the side wall 5b by bend-elongation. Moreover, the portion to be subjected to the necking is ironed at an ironing ratio of not smaller than 5% by the punch 1 in cooperation with the front end 3b.sub.1, of the working corner 3b, or by the front end 3b.sub.1, and an ironing portion of a short cylindrical portion in front thereof, or by the punch 1 in cooperation with the ironing portion 3g of the die 3 by advancing the side wall 5b slightly toward the inside in the cavity 7, thereby to obtain a seamless can 20 having a reduced thickness in the side wall 5b. This method makes it possible to control the thickness distribution in the side wall and, hence, to produce seamless cans having reduced thickness in the side wall permitting the organic film to be least whitened during the necking working.

Method of producing seamless cans

Container

A draw-forming method in which a disc-like metal sheet having an organic film or a cup made of a metal sheet having an organic film is held by an annular holder member and a drawing die, and a drawing punch and the drawing die are moved in mesh with each other and relative to each other, the drawing punch being so provided as to move into or cut of the holder member in concentric with the holder member and the drawing die, wherein at least either one of the annular holder member or the drawing die that had been pushing a residual flange portion is so moved as to discontinue the pushing just before the draw forming is finished in said drawing step, and the flange portion is drawn while liberating the rear end of the flange portion. This makes it possible to eliminate the defects inherent in the conventional draw-forming method or the draw/redraw-forming method, and to draw-form a metal sheet having an organic film into a flangeless cup without developing pinching, film hair or enamel hair at the upper portion of the cup, without causing the can barrel or the organic film to be broken during the drawing, and without permitting the tools that are used to be worn out or damaged, but maintaining excellent operation efficiency.

Method of draw-forming a metal sheet having an organic film

A thickness-reduced deep-draw-formed can obtained by using, as the substrate, a cold-rolled steel plate having a carbon content in the steel of 0.02 to 0.15% by weight, a manganese content in the steel of 0.2 to 1.0% by weight, a mean diameter of crystal grain of smaller than 6.0 .mu.m, a tensile strength over a range of from 35 to 55 kg/mm.sup.2, and a thickness of 0.17 to 0.30 mm in a step of subjecting an organic resin-coated structure of the surface-treated steel plate to the thickness-reducing deep-draw forming. This makes it possible to suppress the generation and accumulation of heat in the organic resin-coated steel plate to a level lower than the conventional levels. Therefore, the organic resin coating is prevented from being peeled off or damaged and, as a result, the corrosion resistance can be markedly improved. Moreover, wrinkles can be effectively prevented from developing at the time of reducing the thickness, and the forming can be continuously carried out at a high speed without being substantially affected by the generation or accumulation of heat. It is further possible to easily carry out the post treatments such as necking, flanging and multi-beading after the forming. The thickness-reduced deep-draw-formed can of the invention is effective particularly for preserving various kinds of juices, coffee, oolong tea and any other beverages after it is hermetically sealed, retort-sterilized and reduced for its internal pressure.

Thickness-reduced draw-formed can

Process for the preparation of a draw-formed printed can

In the production of a thickness-reduced draw-formed can by draw-redraw forming and bending elongation, by using a laminated metal plate comprising a metal plate and a coating layer of a thermoplastic resin having a tension of from 1.times.10.sup.7 to 8.times.10.sup.8 dyne/cm.sup.2 under an elongation of 200% at a temperature of the glass transition point plus 20.degree. C., carrying out redraw forming at a temperature at which the dynamic friction coefficient of the thermoplastic resin is smaller than 0.5 and which is higher than the glass transition point and carrying out bending elongation of the side wall of the can simultaneously with redraw forming, high reduction of the thickness of bending elongation and improvement of the corrosion resistance of the resin-coated vessel can be simultaneously attained.

Process for the preparation of a thickness-reduced draw-formed can

Disclosed is a thickness-reduced deep-draw-formed can, which is prepared by subjecting a resin-coated structure of a surface-treated steel plate comprising, as the substrate, a cold-rolled steel plate having a carbon content in the steel of 0.04 to 0.15% by weight and a manganese content in the steel of 0.3 to 1.0% by weight, an average crystal grain size not larger than 6.0 .mu.m and a tensile strength of at least 65 kg/mm.sup.2, to reduction of the thickness and deep-draw-forming. This can has a high pressure-resistant vessel strength, a high uniformity of the can plate thickness, a high adhesion of the coating and a high corrosion resistance in combination.

In a method for forming a barrel for a two-piece can, before the step of draw-forming the bottom, a taper portion having an inner diameter gradually decreasing toward the bottom surface is formed on a lower part of the side wall of a flat-bottom barrel, corresponding to the outer circumferential frustoconical portion of the bottom of the final barrel or an upper portion contiguous to the outer circumferential portion, and at the step of draw-forming the bottom, at least an upper part of the taper portion is outwardly expanded by insertion of the cylindrical punch. According to this method, a two-piece can having a bottom having a good appearance, a high pressure-resistant strength and an excellent corrosion resistance can be prepared at a high productivity and with a good operation adaptability.

Method for forming barrel for two-piece can

Disclosed is a method of redrawing a metal cup, in which an annular working member is used together with a redrawing die, a redrawing punch and a cup-shaped holding member, and this annular working member has a working face having an inner diameter smaller than the outer diameter of a preliminarily drawn cup to be redrawn. If redrawing is carried out by using this annular working member, the thickness of the drawn cup can be uniformly and sufficiently reduced without damaging a metal sheet of the preliminarily drawn cup or a coating layer thereof.

Method of redrawing metal cup

Disclosed is a redrawing method in which a preliminarily drawn cup having a flange is engaged with a flange-correcting die arranged coaxially with a blank holder to surround the blank holder with a small distance from the peripheral face of the blank holder before the residual flange of the preliminarily drawn cup is introduced into a clearance between the blank holder and a redrawing die, and the preliminarily drawn cup is redrawn in this state. The flange-correcting die has a working face, the inner diameter of which is gradually decreased, and the distance of from the peripheral face of the cup on the tangential line of the working face to the point of the contact with the working face is substantially constant at least in the introduction side portion of the working face. According to this redrawing method, a draw-redraw-formed can having an excellent shape or dimensional precision can be obtained without occurrence of troubles such as edge breaking of the material, breaking of the coating and formation of an enamel hair.

Method of redrawing flanged cup

The present invention provides a redrawing method which comprises holding a preliminarily drawn cup of a covered metal sheet by an annular holding member inserted in the cup and a redrawing die, and relatively moving the redrawing die and a redrawing punch arranged coaxially with the holding member and redrawing cup, said drawing punch being capable of going into the holding member and coming out from the holding member, so that the redrawing die and redrawing punch are engaged with each other, to form a deep-drawn cup having a diameter smaller than that of the preliminarily drawn cup. This redrawing method is prominently characterized in that the radius of curvature of the operating corner portion of the redrawing die is 1 to 2.9 times as large as the bare sheet thickness of the metal sheet. According to this redrawing method, the thickness is effectively reduced by bending and elongating of the side wall, and the variation of the thickness between the upper and lower portions of the side wall is eliminated and the thickness is uniformly reduced as a whole.

Redrawing method and drawn-redrawn can

The present invention provides a redrawing method which comprises holding a preliminarily drawn cup of a covered metal sheet by an annular holding member inserted in the cup and a redrawing die, and relatively moving the redrawing die and a redrawing punch arranged coaxially with the holding member and redrawing cup, the drawing punch being capable of going into the holding member and coming out from the holding member, so that the redrawing die and redrawing punch are engaged with each other, to form a deep-drawn cup having a diameter smaller than that of the preliminarily drawn cup. This redrawing method is prominently characterized in that the radius of curvature of the operating corner portion of the redrawing die is 1 to 2.9 times as large as the bare sheet thickness of the metal sheet. According to this redrawing method, the thickness is effectively reduced by bending anad elongating of the side wall, and the variation of the thickness between the upper and lower portions of the side wall is eliminated and the thickness is uniformly reduced as a whole.

Growing community of inventors

Yokohama, Japan

Tomomi Kobayashi