JPH10235443A - Container can body, and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the wall thickness of a formed container can body without damaging the strength thereof through the drawing - re-drawing operation of drawing - ironing operation by forming a worked part on a closed mouth part of the formed container can body, and adding a simple can-opening mechanism to the worked part. SOLUTION: A projecting part 6a of formed on a circumferential edge part in the circumferential direction of a closed mouth part 6 of a can body 7, and a simple can opening mechanism is added to the center of the closed mouth part which is a recessed part. An opening part of the can body 7 is trimmed to form a two-piece can, and a bottom plate is seamed to the opening part after the content is filled to make a canned food. In order to execute the additional work to the closed mouth part 6 formed through the drawing - re-drawing operation or the drawing - ironing operation, the strength of the can body 7 is more excellent than that of the stock sheet through there is some difference in strength caused by the difference in the working degree at many parts. The prescribed strength higher than the required strength of the can body can be secured even at a can body part and the closed mouth part 6 formed of the soft material of excellent workability making use of the effect. The can body 7 is reduced, and neck-in can be omitted, and the can manufacturing cost is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a container can and a method for producing the same.

[0002]

2. Description of the Related Art In the manufacture of a container can, a side wall and a bottom of the can are simultaneously formed by drawing-redrawing or drawing-ironing using a coated metal sheet as a raw material. Japanese Unexamined Patent Publication No. Hei 5-117760 discloses manufacturing an opening having a predetermined outer diameter, and winding a can lid having an easy-open mechanism to produce a one-piece molded can, a so-called two-piece can. Have been. A molding method or a molding machine for preventing wrinkles and breakage of a can body generated during neck-in processing is disclosed in JP-A-63-1156.
No. 23, and Japanese Patent Application Laid-Open No. Hei 1-210135.

[0003]

In the above-described step of forming a container can, the side wall of the can is made thinner by drawing-redrawing or drawing-ironing, and hardened by work hardening. The increase in the work hardening increases as the ratio of thinning increases, that is, increases as the thickness reduction rate increases, and the secondary workability, particularly elongation, of the material deteriorates. On the other hand, from the viewpoint of cost reduction in can body manufacturing, the thickness of the can body has been increasingly reduced, and the opening diameter of the can body has also been reduced along with the reduction of the can lid diameter in order to reduce the weight of the can lid. It has been demanded. The work hardening allowance of the material has become very large due to the increase in the reduction rate of the material thickness at the time of molding, and in the neck-in processing to adapt the diameter with the can lid in the post-process,
The neck-in process is more difficult because the elongation value is reduced by work hardening of the material during can making. Also,
Further, as described above, the processing of the can body opening becomes more difficult due to the need for diameter reduction. As described above, when the thickness reduction rate during can making becomes large, the working margin of the can body itself for performing neck-in processing becomes small, and there is a possibility that neck-in processing itself may become impossible, so that Inevitably, there is a limit to the reduction of the thickness. Also, in order to make neck-in processing easier, the thickness of the material before can-making is reduced to reduce the reduction rate of the thickness of the material during processing to reduce the work hardening allowance and the strength of the material itself ( (Hardness) may be reduced in advance. However, for example,
In the case of a beverage can, the can is usually 7 to 8 kg / cm ² in a can body after making the can.
Pressure resistance of the bottom of the can, which is hardly subjected to processing during can-making, may not be able to be secured, and there is a limit to simply reducing the thickness of the material or reducing the strength (hardness). And other issues. The present invention has been made to advantageously solve such problems, and it is possible to reduce the thickness of the can without reducing the strength of the container can formed by drawing-redrawing or drawing-ironing. It is an object of the present invention to provide a container can and a method for molding the same.

[0004]

A feature of the present invention is that the first invention is characterized in that a processing portion is formed in a closed portion of a molded container can body, and a simple opening mechanism is attached to the processing portion. And container can body. A container can body according to the second invention, wherein an opening is formed in a closed portion of the molded container can body. According to the third aspect of the present invention, the container can body is formed, and after forming the mouth portion in the closing portion, the mouth portion of the molded container can body is inserted and arranged in the mold having the spiral groove, and the inside of the molded container can body is pressurized. A method for producing a container can, characterized in that a cap screw is formed at the mouth. A fourth aspect of the present invention is a method for manufacturing a container can, characterized in that the container can is molded and a convex portion is formed in a closed portion.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The material of a can body to be molded as in the present invention may be any material generally used as a material for a can body, and various surface-treated steel plates and light metal plates such as aluminum may be used. It is listed as an object. As the surface-treated steel sheet, for example, a galvanized, tin-plated, nickel-plated, electrolytic chromic acid treatment, chromic acid treatment, phosphoric acid treatment, chromium One or more surface treatments such as acid / phosphoric acid treatment can be used. An example of a desirable surface-treated steel sheet is an electrolytic chromic acid-treated steel sheet,
10 to 200 mg / m ² metal chromium layer and 1 to 50 mg
/ M ² (converted to chromium metal) with a chromium oxide layer, which is excellent in coating film adhesion and corrosion resistance. As the light metal plate, an aluminum alloy plate is used in addition to the above-described aluminum plate. An aluminum alloy plate excellent in corrosion resistance and workability is Mn: 0.2 to 1.5% by weight, Mg: 0.8 to 5% by weight, Zn: 0.25 to 0.5%.
Optimum is one having a composition of 3% by weight and Cu: 0.15 to 0.25% by weight, with the balance being Al. These light metal plates also desirably have been subjected to chromic acid treatment or chromic acid / phosphoric acid treatment so that the chromium amount becomes 20 to 300 mg / m ² (in terms of metal chromium). Further, the plate thickness is 0.12 to 0.30 mm, and can bodies currently used can be manufactured.

[0006] Further, those obtained by protectively coating a paint or a thermoplastic resin film on such various surface-treated steel plates or light metal plates can also be used. Examples of the paint include paints composed of thermosetting and thermoplastic resins, such as phenol, epoxy paint, and modified epoxy paints such as amino-epoxy paints, such as vinyl chloride-vinyl acetate copolymer and vinyl chloride-vinyl acetate copolymer. Partially saponified, vinyl chloride
Vinyl acetate-maleic anhydride copolymer, epoxy-modified
One or two or more vinyl or modified vinyl paints such as vinyl paint, epoxyamino-modified vinyl paint, or epoxyphenol-modified vinyl paint, acrylic resin paints, and synthetic rubber paints such as styrene-butadiene copolymers Can be used.

Examples of the thermoplastic resin film include olefin resin films such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acryl ester copolymer, and ionomer, polyethylene terephthalate, and polybutylene. Polyester film such as terephthalate, ethylene terephthalate / isophthalate copolymer, or nylon 6, nylon 6.6, nylon 11, nylon 1
Polyamide films such as No. 2 and the like, further, polyvinyl chloride films, polyvinylidene chloride films, and the like.

As described above, when a container can body composed of a can body and a closed portion is processed by draw-redrawing or draw-ironing as described below, the material is processed into a closed portion. By forming the part, the strength of the closed part is improved, and the strength of the can body is ensured by approaching the strength of the can body after processing. Therefore, it is not necessary to increase the thickness of the material to secure the strength of the closing part, so that the can body can be made thinner, and the thickness can be reduced without lowering the strength of the can body. Since a can opening mechanism is added, the neck-in process for reducing the diameter of the can lid by a large amount at the opening can be omitted or greatly simplified.
The generation of wrinkles and the like can be prevented, the quality and yield of the can body can be improved, and the cost due to weight reduction (thinning) can be reduced.

[0009] As a processing portion to be formed into such a can closed portion, for example, a convex portion or a can body is formed in the closed portion at the same time as the can body is formed by a punch and a die at the center portion of the closed portion when a container can is formed. The circumferential part of the closing part in the circumferential direction is formed in a convex shape, the center part of the closing part is formed in a concave part, and the strength of the closing part is improved by work hardening to secure the strength as a can body. As a simple can opening mechanism, for example, a commonly used easy-open mechanism is attached near the center of such a closed portion to serve as an outlet for can contents. Further, a mouth portion is formed in the can body closing portion, and the closing portion is work-hardened so that the strength of the closing portion is close to the strength of the can body portion by the can body molding, and the can body can be formed into a bottle shape.

Next, an example of forming the container can of the present invention will be described with reference to the drawings. In FIG. 1, the punch 4 descends in a state where the cup-shaped one subjected to the drawing process in the previous process is pressed against the die 3 with a predetermined load by the wrinkle holder 2,
As shown in FIG. 2, re-drawing is performed after passing through the die 3 to form a can body 5, and the can body 7 (the can body 5) passing through the die 3 is formed.
The closing portion 6) of the can 7 is formed into a shape defined by the punch 4 and the closing portion processing die 8 by the closing portion processing die 8 provided on the lower surface of the die 3. In order to allow the closing portion 6 of the can body 7 to function as a can lid portion, a simple can opening mechanism such as an easy-open mechanism with a can opening tab 15 attached to the score 14 processing portion shown in FIG. I do. In addition to the shape of the closing portion 6 of the can body 7,
For example, a shape as shown in FIG. 4 can be formed.
That is, since the shape can be formed as shown in FIGS. 4A and 4C, the neck-in processing can be greatly simplified.

Further, as shown in FIG. 5, a can body 5 is formed by a punch 4 and a die 8 for forming a closed portion.
After processing the closing portion 6 of the can body 7 into a protruding shape as illustrated,
As shown in FIG. 6, a spiral groove 10 is formed in the concave portion of the mold frame 9, and the convex portion 6a of the can is located in the concave portion. For example, acryl nitrile rubber, latex rubber, butyl rubber, silicon rubber, urethane rubber The elastic body 11 having a hardness Hs 70 or less, preferably about Hs 40 is arranged. Thus, by pressing the elastic body 11, the can 7 is expanded and formed along the mold 9 to form a bottle-shaped can as shown in FIG. 7, and the convex portion 6 a is formed into a mouth having a cap screw 12. I do. In addition to the expansion molding of the can 7 along the mold 9 via the elastic body 11 as described above, the expansion of the can 7 along the mold 9 by, for example, liquid pressure (water pressure), gas pressure, or the like. Can also.

[0012] Further, as shown in FIG.
A convex portion 13 is formed on the peripheral edge of the opening portion 6, and the closing portion 6 is processed into a concave portion, and a simple can opening mechanism is attached to the central portion of the closing portion 6. The opening of such a can 7 is trimmed into a two-piece can, and after filling the contents, a bottom plate is arranged in the opening to be canned. Such a bottom plate,
For example, a material having a predetermined thickness and strength by rolling,
It is arranged by winding around the opening of the can body. The joint between the can body and the bottom plate only needs to satisfy the pressure resistance. For example, a joining method usually used for a container can, such as winding and resistance welding, can be appropriately selected.

As described above, the processing of the closed portion is performed at the same time as redrawing. However, the closed portion can be formed at the same time as ironing, after redrawing, or after ironing. The shape of the can body closing portion processed and formed by the pair of punches and dies is arbitrarily determined by the design of the can body as a product. Since the closing portion is subjected to considerable processing depending on its design shape, the strength of the closing portion is increased by work hardening by forming the closing portion. Therefore, in the production of conventional can bodies,
Since the closed part formed by drawing-redrawing or drawing-ironing is used as the bottom of the can, the closed part is hardly processed, so the strength of the bottom of the can is equivalent to the strength of the coated metal plate before drawing. Become. For this reason, in order to ensure the strength as a can body container, it is necessary to make the strength of the coated metal plate before processing equal to the strength of the product. For this reason, when a high can body strength is required, the strength of the coated steel sheet before processing must be increased, and the forming becomes more difficult. In the present invention, since the closed portion formed by drawing-redrawing or drawing-ironing is further processed, the strength of the can body is increased in many parts (for example, the closed portion, the can body portion, the inside of the closed portion). However, although there is a difference in strength due to the difference in the degree of processing of the molded part, the strength is higher than that of the blank. By utilizing this effect, it is possible to secure a predetermined strength not only in the can body but also in the closed part using a material softer than the required can body strength of the product, that is, a material having good workability. Processing is made easier by the use of soft materials, as it is possible. Then, a simple can opening mechanism or a mouth portion is formed in the formed closing portion to serve as a lid portion of the container can body. As the simple can opening mechanism, for example, an easy opening mechanism may be provided by applying a method used in the conventional manufacturing of a can lid.
And the can after molding performs trimming of the can body opening,
It becomes a one-piece molded body, that is, a two-piece can body.

[0014]

Next, examples of the present invention will be described together with comparative examples. Example 1 A container body as shown in FIG. 9 was formed. The dimensions are L
₁ = 65 mm, L ₂ = 61 mm, h ₁ = 140 mm, h
₂ = 2 mm, r ₁ = R1 mm. Raw material thickness 0.2 as material
Palm oil was applied to a coated metal plate obtained by laminating polyethylene terephthalate (thickness: 20 μm) on tin-free steel (metal chromium 60 mg / m ² , chromium oxide 10 mg / m ² ) having a temper of DR-8 mm and a diameter of 180 mm.
And a draw-redrawing process was carried out by a conventional method to form a cup between the draw punch and the draw die and between the redraw punch and the redraw die. This drawing ratio is 1.6 and the redrawing ratio is 1.4. Then, the can body 7 is formed from this cup-shaped body by re-drawing and ironing using a closing portion processing die 8 (made of a die SKD11) as shown in FIG. Was formed into a shape having a jetty 13 formed by folding back into a U-shaped cross section. The re-drawing ratio is 1.2, the die shoulder radius of curvature r ₁ : 0.4 mm, the wrinkle holding shoulder radius of curvature r
₂ : 1.5 mm, radius of curvature of punch shoulder r ₃ : 3.0 mm
And the sheet thickness reduction rate was 40%. Then, a can body 7 having a jetty 13 formed by folding the periphery inward into a U-shaped section at the closed portion 6 was obtained. Then, the can 7 closing part 6
3 shows a score 14 as shown in FIG.
With the easy open mechanism 16 attached,
A can body of a molded body can was manufactured.

Example 2 A container can was formed as shown in FIG. The dimensions are L
₁ = 65 mm, L ₂ = 20 mm, L ₃ = 16 mm, h ₁
= 15 mm, h ₂ = 140 mm, h ₃ = 2 mm, r ₁ =
R3mm, r ₂ = R3mm. Raw material thickness 0.18 as material
Palm oil was applied to a coated metal plate obtained by laminating polyethylene terephthalate (thickness: 20 μm) on tin-free steel (metal chromium 80 mg / m ² , chromium oxide 20 mg / m ² ) having a temper of DR-8 mm and a diameter of 180 mm.
Was punched into a circular plate, and formed into a cup shape by drawing, re-drawing and re-drawing in a conventional manner. This aperture ratio is 1.6,
The re-drawing ratio is 1.4 and the re-drawing ratio is 1.2. Then, this cup-shaped body was formed by folding the periphery of the inside of the closed portion 6 of the can body 7 into a U-shaped cross section using a closed portion processing die 8 (made of a mold SKD11) as shown in FIG. A can 7 having a convex portion 6a was formed. Next, an elastic body 1 made of urethane rubber Hs: 40) as shown in FIG.
1 and a mold 9 (manufactured by SS400), a can body 7 having a convex portion 6 formed therein is inserted and arranged in a mold frame 9, an elastic body 11 is arranged in the can body 7, and a load is applied from above the elastic body 11. (2000kg)
Is applied to form a cover screw 10 (spiral groove) in the convex portion (mouth) 6a, and then the opening of the can body 7 is trimmed.
The closed part of a was opened to manufacture a bottle-shaped one-piece can, that is, a two-piece can.

Example 3 A container can was formed as shown in FIG. Dimensions are L ₁ = 65 mm, L ₂ = 54 mm, h ₁ = 140 m
_{m, h 2 = 10mm, r} 1 = R3mm, r 2 = R3m
m. As a raw material, a palm is coated on a coated metal plate obtained by laminating polyethylene terephthalate (thickness: 20 μm) on tin-free steel (metal chromium 60 mg / m ² , chromium oxide 10 mg / m ² ) with a raw material thickness of 0.26 mm and a temper of DR-8 Oil was applied and punched into a disk having a diameter of 180 mm, followed by drawing and redrawing in a conventional manner to form a cup between the drawing punch and the drawing die and between the redrawing punch and the redrawing die. The aperture ratio is 1.6 and the re-aperture ratio is 1.4
It is. Then, the cup-shaped body is closed using a die 8 (made of die SKD11) as shown in FIG.
The can body 7 was formed by re-drawing and ironing, and at the same time, the closed portion 6 was formed into a shape having a jetty 13 formed by folding the periphery inward into a U-shaped section. The re-drawing ratio is 1.2 and the radius of curvature at the shoulder of the die r ₁ : 0.4 m
m, wrinkle holding shoulder radius of curvature r ₂ : 1.5 mm, punch shoulder radius of curvature r ₃ : 3.0 mm, and sheet thickness reduction rate is 4
It became 0%. And the can body 7 which has the convex part 6a in the center part of the closing part 6 was obtained. Next, the concave portion 6a of the can 7 closing portion 6
An easy-open mechanism 16 in which a score opening 14 was attached to the processed part of the score 14 as shown in FIG.

Example 4 A container can was formed as shown in FIG. Dimensions are L ₁ = 65 mm, L ₂ = 54 mm, h ₁ = 140 m
_{m, h 2 = 10mm, r} 1 = R3mm, r 2 = R3m
m. Al-Mg based A with raw plate thickness 0.26mm as material
The l-alloy is coated with an epoxy paint and baked. After drying, palm oil is applied to a coated metal plate having a protective film of about 20 μm formed thereon, punched into a 180 mm diameter disk, and drawn and redrawn in a conventional manner. Between the drawing punch and drawing die,
And, it was formed into a cup shape between the redrawing punch and the redrawing die. This drawing ratio is 1.6 and the redrawing ratio is 1.4. Then, the cup-shaped body is formed again by re-drawing and ironing using a closing part processing die 8 (made of a mold SKD11) as shown in FIG.
The closing part 6 was formed into a shape having a jetty 13 formed by folding the periphery inward into a U-shaped section. The re-drawing ratio was 1.2, the die shoulder curvature radius r ₁ : 0.4 mm, the wrinkle holding shoulder curvature radius r ₂ : 1.5 mm, the punch shoulder curvature radius r ₃ : 3.0 mm, and the plate thickness. The reduction rate was 40%. And the can body 7 which has the convex part 6a in the center part of the closing part 6 was obtained. Next, as shown in FIG. 3, a score 14 processing portion is provided at the center of the concave portion 6a of the
5 was attached and an easy-open mechanism 16 was attached to manufacture a one-piece can.

COMPARATIVE EXAMPLE 1 Using the material shown in Example 3, palm oil was applied and a diameter of 18 was applied.
A cup-shaped body that has been punched into a 0 mm disc and drawn and redrawn with a drawing ratio of 1.6 and a redrawing ratio of 1.4 has a thickness reduction rate of 40% at a redrawing ratio of 1.2. A two-piece can body was manufactured with the closed part of the processed cup-shaped body as the bottom part, and a neck-in process for attaching a 202-diameter can lid to the opening part was performed.

Comparative Example 2 Using the material shown in Example 4 and applying palm oil,
A cup-shaped body that has been punched into a 0 mm disc and drawn and redrawn with a drawing ratio of 1.6 and a redrawing ratio of 1.4 has a thickness reduction rate of 40% at a redrawing ratio of 1.2. A two-piece can body was manufactured with the closed part of the processed cup-shaped body as the bottom part, and a neck-in process for attaching a 202-diameter can lid to the opening part was performed.

Next, the properties of the cans according to the above Examples and Comparative Examples will be described.

[Table 1]

Note 1: Hardness is Vickers hardness. Note 2: The product rejection rate indicates the rejection rate due to cracking, wrinkling, etc. when 500 cans are manufactured and neck-in processing is performed. As described above, according to the present invention, since the can body having excellent hardness can be formed in both the can body portion and the can closing portion, the can body can be thinned,
Costs can be reduced. On the other hand, in the comparative example, the strength of the can closed portion is low, so that it is impossible to reduce the wall thickness, and furthermore, the neck-in processing for reducing the diameter increases the product rejection rate and increases the cost. Will do.

[0022]

According to the present invention, in the production of a container of a can body formed by drawing-redrawing or drawing-ironing, the thickness of the can can be reduced without impairing the strength of the can, and the neck can be further reduced. In-processing can be omitted or greatly simplified, and can-making cost can be improved. Further, since the closed portion of the can body is processed at the same time as the can is formed, the strength of the closed portion can be easily increased, so that excellent effects such as can production while maintaining high productivity can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing a can manufacturing process according to the present invention.

FIG. 2 is a side view showing a can manufacturing process according to the present invention.

FIG. 3 is a plan view of a simple can opening mechanism.

FIG. 4 is a side view showing an example of the shape of a can according to the present invention.

FIG. 5 is a side view showing a can manufacturing process according to the present invention.

FIG. 6 is a side view showing a can manufacturing process according to the present invention.

FIG. 7 is a side view showing an example of the shape of a can according to the present invention.

FIG. 8 is a side view showing a can manufacturing process according to the present invention.

FIG. 9 is a side view showing an example of the shape of a can according to the present invention.

[Explanation of symbols]

 6 Can body closing part 6a Processing part of can body closing part 6a Mouth of closing part 7 Can body 16 Simple can opening mechanism

Claims (4)

[Claims] 1. A container can body characterized in that a processed part is formed in a closed part of a molded container can body and a simple can opening mechanism is attached to the processed part. 2. A container can body characterized in that a mouth portion is formed in a closed portion of the molded container can body. 3. A container can body is formed, and a mouth is formed in a closed portion. Then, the mouth of the molded container can is inserted and arranged in a mold having a spiral groove, and the inside of the molded container can is added. A method for producing a container can, characterized in that a lid screw is formed at a mouth portion by pressing. 4. A method for producing a container can, wherein the container can is molded and a convex portion is formed in a closed portion.