JP3059075B2 - Can with resin film adhered to weld and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a can having a hand ring (handle) formed by spot welding or the like on a can lid, such as a 5-gallon can (18 liter can) or a pail can, or a seam welding at both ends. The present invention relates to correction of a welded portion of a can having a can body formed by joining by a method such as described above.

[0002]

2. Description of the Related Art Cans having a hand ring (handle) provided by spot welding on a can lid (top plate) such as a 5-gallon can (18 liter can) or a pail can, or both ends are joined by seam welding. In a can having a welded portion, such as a can having a can body formed in such a manner, the welded portion is particularly susceptible to rust, and as it is, the generated rust mixes with the content, and adversely affects the content. Therefore, in a can having a welded portion, coating of the welded portion is performed (this is referred to as correction of the welded portion).

Conventionally, the correction of the welded portion has been performed by means of paint correction by spraying the paint with a spray or powder correction by fixing the powder paint by electrostatic action.

[0004]

However, the thickness of the paint that can be applied by the spray means is 10 to 20 μm at a time, and the maximum thickness is about 30 μm. It had to be applied more than once. Further, since the welded portion 2d usually has a projecting portion and a stepped portion, there is a problem that a portion having a small paint thickness still occurs even if the portion is applied a predetermined number of times. That is, for example, when the hand ring portion 2a is spot-welded to the spot welding portion 2d of the can lid 2 shown in FIG. When the paint is applied on the protruding portion 2g, the top of the protruding portion 2g becomes a portion 5 where the paint thickness is small.
In this portion, there is a problem that the required paint thickness cannot be obtained even if the paint is applied a predetermined number of times. Accordingly, there has been a problem that the conventional correction of the welded portion, which is performed by applying the paint by using the spraying means, requires a long operation time, and thus increases the cost, and it is difficult to obtain a sufficient correction quality.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a can and a method for manufacturing the same, which can perform correction of a welded portion in a short working time and obtain sufficient quality.

[0006]

Means for Solving the Problems In order to achieve the above object, a can according to the present invention comprises a can lid provided with a hand ring by spot welding on a can lid. It is characterized in that a resin film is fixed and coated on the outer peripheral laminated resin coating.

Further, the above-mentioned can has a can body formed by joining both ends by seam welding, and a resin film is fixed to the seam weld.

[0008] The resin film is fixed to the welded portion by placing the resin film on the welded portion, heating the resin film, softening the resin film, and bringing the resin film into close contact with the welded portion. desirable.

The resin film is preferably a thermoplastic resin film made of any one of polyester, polyethylene and polypropylene tapes.

[0010]

In a can having a hand ring formed by spot welding on the can lid, a resin film is fixed to the spot weld and a can body having both ends joined by seam welding is used for seam welding. Fix the resin film to the part,
The correction of the weld is performed. Therefore, the correction of the welded portion can be performed with one resin film having a predetermined thickness, so that the work time for correcting the welded portion is short, and the necessary thickness is required even at the protrusions and steps of the welded portion. Can be obtained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. The present embodiment is a case of a 5-gallon can having a hand ring portion (handle portion) provided on a can lid by spot welding and having a can body formed by joining both ends by seam welding. . In addition, the resin film is fixed to both the spot weld of the can lid and the seam weld of the can body according to the present invention.

First, a case where a resin film is fixed to the can lid 2 of the 5-gallon can 1 will be described (FIG. 1).

First, a shape before the hand ring portion 2a of the can lid 2 is attached is formed (FIG. 1A). This is achieved by laminating a resin film 2b on one surface (to be on the back side of the can lid 2) and pressing a laminated steel plate 2c with a mold press (not shown).
It is performed by processing. The attachment portion 2d of the hand ring portion 2a has a predetermined uneven surface 2k so that spot welding with the hand ring portion 2a can be reliably performed. In addition, can lid 2
Is provided with an entrance 2e for taking in and out the contents. The peripheral portion of the laminated steel plate 2c is bent to the side where the hand ring portion 2a is attached, and the bent end portion 2 is formed.
This portion is fitted to the upper end 3m of the can body 3 and then caulked as described later.

Then, the portion where the spot welding is performed, that is, the resin film 2b of the attachment portion 2d of the hand ring portion 2a is removed by a predetermined method (not shown) so as to be able to conduct electricity (FIG. 1A). . Next, the hand ring portion 2a is attached by predetermined spot welding (not shown) (FIG. 1).
(B)). At this time, each spot welding point 2g projects on the back surface side (upward direction in FIG. 1) of the can lid 2 (see FIG. 4).

Next, a thermoplastic resin film 2h to be described later
Of the hand ring portion 2a on the back side of the can lid 2 and the periphery thereof are cleaned with a detergent or the like to remove dirt. Then, with the back side of the can lid 2 facing upward (the state of FIG. 1), a thermoplastic resin having a thickness of 50 to 100 μm, which is larger than the area of the removed laminated resin film 2b, is placed thereon. The resin film 2h is positioned so as to cover the removed laminated resin film 2b, that is, in a state where the entire periphery 2i of the thermoplastic resin film 2h can be superimposed on the unremoved laminated resin film 2b. Then, it is placed (FIG. 1 (c)). A tape (film) of polyester or the like is used as the thermoplastic resin film 2h. As this tape, a thermoplastic resin film such as polyethylene and polypropylene can also be used. If it is a thermoplastic resin, it can adhere to the back side of the can lid 2 by heating means such as an oven (thermal fusion). Then, the opposite two ends 2j of the thermoplastic resin film 2h are temporarily fixed with an adhesive or the like (FIG. 1C).

Then, in a state shown in FIG. 1C, that is, in a state where the resin film is placed on the welded portion with the welded portion down, the can lid 2 is passed through an oven and heated. The temperature in the oven is usually set at 50 ° C. to 500 ° C. (the temperature varies depending on the type of film), and the film is passed through the oven over a period of several seconds to several minutes. For a film having a low melting point such as polyethylene or polypropylene, the temperature is set to a low temperature (for example, 50 to 300 ° C.). In addition,
At this time, the thermoplastic resin film 2h is temporarily fixed (2j).
As a result, movement and displacement due to wind are prevented. The laminated resin film 2b is also heated to a temperature close to the temperature in the oven, but since the laminated resin film 2b is already laminated and fixed to the steel plate,
This prevents the laminated resin film 2b from melting and shrinking. Next, due to this heating, the thermoplastic resin film 2h softens and descends under the influence of gravity, and the uneven surface 2k of the attachment portion 2d of the hand ring portion 2a of the can lid 2 located below.
The shape is changed according to the formula (1), and finally, the surface is closely adhered and fixed (FIG. 1 (d)). Since the peripheral portion 2i of the thermoplastic resin film 2h overlaps and adheres to the unremoved laminated resin film 2b, the bonding strength of the peripheral portion 2i to the can lid 2 is extremely high. The thermoplastic resin film 2h sufficiently adheres and adheres along the shape of the projection of the spot welding point 2g on the back side of the can lid 2 generated during spot welding. In this case, since the thermoplastic resin film 2h is stretched to some extent, the thickness of the film becomes thinner at the top of the spot welding point 2g or the like, but the film is not in a liquid state. Still maintained.

Next, a case where a resin film is fixed to the can body 3 of the 5-gallon can 1 will be described (FIG. 2).

First, a resin film 3b from which a weld has been removed is laminated on one surface of the steel sheet cut to the size of the developed area of the can body 3 (on the inner surface side of the can body 3). Next, both ends 3d of the laminated steel plate 3c are overlapped with each other, and this portion is welded by seam welding. Then, this is bent to form a rectangular cross section. Then, with the seam weld 3g of the laminated steel plate 3c facing downward (the state of FIG. 2), a thermoplastic resin film 3h having substantially the same area as the area of the weld is placed thereon, in a state of covering the weld. A predetermined portion is temporarily fixed (not shown). And
As in the case of the can lid 2, the thermoplastic resin film 3h is softened by passing through the oven, closely adhered along the shape of the can body, and fixed thereto.

As shown in FIG. 3, the can lid 2 and the can body 3 and the separately formed can bottom 4 manufactured as described above are connected to the upper end of the can body 3 as shown in FIG. 3m and the lower end 3n, and are fitted to each other to form a bent end 2f of the can lid 2, an upper end 3m of the can body 3, a bent end 4f of the can bottom 4, and a lower end of the can body 3. The parts 3n are caulked to each other by using a predetermined caulking member (not shown), and the entrance 2e of the can lid 2 is formed.
A lid (not shown) is attached to the container so that a 5-gallon can 1
Is produced.

In the 5-gallon can 1 manufactured in this manner, various contents are stored from the entrance 2e. There are various kinds of contents such as solvent, petroleum, gasoline, etc. If the correction of the welded part is performed by spraying paint as in the past, depending on the type of the contents to be stored, Since the paint to be sprayed was changed so that the correction paint would not melt, there were many types of 5-gallon cans, and be careful not to mistake the relationship between each type of 5-gallon can and the contents stored in it. I needed to. However, since the resin films 2h and 3h are resistant to a wide variety of contents, the types of contents applicable to one type of resin film are extremely large,
Therefore, in the present invention, the number of types of the 5-gallon cans can be greatly reduced, and therefore, the consideration for ensuring that the relationship between the 5-gallon cans of each type and the contents stored therein is not mistaken can be greatly reduced. .

Although the above-mentioned embodiment is a 5-gallon can, the present invention relates to a so-called half-cut can in which the height of the 5-gallon can is reduced to half, and a pail (20 liter) having a circular can body in cross section.
Of course, the present invention can be applied to various cans provided with a hand ring by spot welding on a can lid. Further, the present invention is not only a case where a resin film is fixed to a spot welded portion on the back side of the can lid, in a can provided with a hand ring portion by spot welding on the can lid,
As in the above embodiment, the case where the thermoplastic resin films 2h and 3h are fixed to both the spot weld 2d of the can lid and the seam weld 3g of the can body is included in the present invention.

Further, in the above embodiment, the correction of the welded portion of the steel sheet on which the laminated resin films 2b and 3b are laminated is applied. However, the present invention applies to the steel sheet on which the laminated resin films 2b and 3b are not laminated, that is, the surface. Of course, the present invention can be applied to a steel sheet that has not been treated or a plated steel sheet that has been subjected to a plating surface treatment. In this case, the peripheral portions (2i) of the thermoplastic resin films 2h and 3h
Directly adheres to the ground surface or plated surface of the steel sheet.

[0023]

As described above, the present invention is configured as described above, so that the time required for the work of correcting the welded portion is greatly reduced,
In addition, a high-quality can having a required correction thickness can be obtained.

[Brief description of the drawings]

FIGS. 1 (a), 1 (b), 1 (c) and 1 (d) show steps of fixing a resin film to a spot-welded portion according to the present invention in a can lid provided with a hand ring portion by spot welding on a can lid. It is a perspective explanatory view.

FIG. 2 is a perspective explanatory view showing a state in which a resin film is fixed to a seam welded portion according to the present invention in a can having a can body formed by joining both ends by seam welding.

FIG. 3 is an explanatory perspective view illustrating fitting of a can lid 2, a can body 3, and a can bottom 4;

FIG. 4 is an explanatory cross-sectional view when a weld is corrected by spraying a conventional paint.

[Description of Signs] 1. A can having a hand ring portion provided on a can lid by spot welding or a can having a can body formed by joining both ends by seam welding. 2 Can lid 2a Hand ring 2d Spot weld 2h Thermoplastic resin film 3 Can body 3d Both ends of can body joined by seam welding 3g Seam weld 3h Thermoplastic resin film

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B65D 6/00-13/02 B65D 23/00-25/56

Claims (4)

(57) [Claims] In a can having a hand ring formed by spot welding on a can lid made of a laminated steel plate, a resin film is fixed on a spot welded portion on the back side of the can lid by superimposing the laminated resin coating on the outer periphery of the welded portion. A can characterized by being coated. 2. The can according to claim 1, wherein the can has a can body formed by joining both ends by seam welding, and a resin film is fixed and covered on the seam weld. 3. The can according to claim 1, wherein the resin film is a thermoplastic resin film formed of a tape of polyester, polyethylene, or polypropylene. 4. The resin film is fixed to the welded portion by placing the resin film on the welded portion, heating the resin film, softening the resin film, and fixing the resin film on the welded portion. The method for producing a can according to any one of claims 1 to 3, wherein the method is carried out in close contact with the can.