JPS6254699B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) This invention involves bonding and fixing the can body joints of a large metal can by electric welding to form a can body. This relates to a method for manufacturing metal cans in which the top and bottom plates are secured together using an adhesive, and belongs to the industrial field of manufacturing metal cans.

(Prior Art) In many conventional metal cans, solder was applied to the joints of the can body and the seams between the can body and the top and bottom plates to ensure airtightness and maintain strength.
In recent years, solderless cans have been proposed and put into practical use for the purpose of streamlining production lines and preventing pollution (Special Publication No. 30512/1983). The solderless can is one in which an adhesive is interposed in the joint of the can body and the seamed part between the edge of the can body and the periphery of the top and bottom plates (Special Publication No. 50-1983).
No. 30512) A known technique was to apply adhesive to the top and bottom plates, especially for the seaming part.

Also known was a can in which the joints of the can body were electrically welded and top and bottom plates were secured to the top and bottom ends of the can (Utility Model Publication No. 49-23371).

(Problems to be solved) When manufacturing large metal cans (for example, 18-liter cans) using the conventional can manufacturing method, it is necessary to solder or maintain airtightness in order to strengthen the joints of the can body. Special consideration must be given to the welding and strength retention, and the application of adhesive to the top and bottom plates makes it difficult to increase the speed. In the case of welding, there were problems such as the need for post-processing of the part.

In addition, even for cans in which the joints of the can body are electrically welded and the top and bottom plates are secured to the edges of the can body, the adhesive is applied to the top and bottom plates, which results in poor application efficiency. However, because it was difficult to apply the adhesive uniformly and it was likely to be uneven, and there was no special consideration (adhesive application) for the seaming part of the welded part of the can body, there were problems with its airtightness. It had not been improved.

(Means to solve the problem) However, in this invention, the can body joint is electrically welded,
By applying an adhesive to the edge of the can body and sealing it to the periphery of the top and bottom plates, high-speed production becomes possible and the problems of the conventional can are solved.

That is, in this invention, after cutting and removing the adhesive adhered to the welded edge of a can body plate for a large metal can whose seamed edge is coated with adhesive, the welded edge is polished and cleaned over a predetermined width, and then the The can body plate is framed and bent to form a rectangular tube shape, the welded edges of the rectangular tube-shaped can body are overlapped and this portion is electrically welded, and then varnish or other treatment liquid is applied to the electric welded portion. After that, apply adhesive to the upper and lower parts of the weld to be seamed and let it dry. Then, after folding the upper and lower edges of the can body, apply adhesive to the top and bottom of the can body. The base plate is brought into contact with the can body, the upper and lower edges of the can body and the periphery of the top and bottom plate are successively secured by seaming, and the seamed portion between the top and bottom plate and the can body is heated to correct the fusion of the adhesive to form a metal can. Manufacture.

In the above, if the adhesive is a liquid and is dried after being applied to the can body plate, after preliminary drying,
Main drying is desirable. In addition, correction of the upper and lower ends of the electrically welded part of the can body using adhesive should be performed immediately after applying varnish or other treatment liquid to the electric welded part, or the treatment liquid should be dried and then corrected with adhesive. You can also do it.

In this invention, since the adhesive is applied to the seam edge of the can body before forming the can body, high-speed application is possible. Furthermore, since the joint edges of the can body are welded, the number of overlaps is smaller than that of seams, and therefore the seam portion of the joint edges does not protrude excessively. In addition, since the welding edge is polished and cleaned over a specified width before welding the can body, it is possible to improve the welding quality and reduce power consumption (since the surface treatment coating is removed, the power consumption is reduced compared to when welding the original plate). ). Further, by correcting the heating of the seamed portion, processing cracks in the adhesive can be effectively corrected and airtightness can be improved.

(Embodiment 1) That is, to explain the present invention with reference to the embodiment shown in FIG. Adhesive layers 4, 4 having a narrow width (for example, 5 mm) are provided on the substrate. This adhesive is applied uniformly at high speed by a coating roll 5 using, for example, an aqueous dispersion of a resin containing an olefin copolymer resin having a carboxyl group in its side chain. The can body plate 1 coated with the adhesive is heated to a can material temperature of 50°C in a pre-dryer 6.
After pre-drying at a temperature of ~70°C, the main dryer 7 is used, first at 50-60°C, then at 90-100°C, and finally at 130°C.
Dry sequentially at ~150°C. Next, the adhesive is firmly fixed to the can body plate by cooling it naturally in a cooler 8.

The adhesive in the above is applied over the entire length of the seaming edge of the can body plate 1, so that the parts 1b, 1b to be electrically welded in the seaming edge (slight width at both ends of the can body plate)
The adhesive is removed by cutting with the cutting blade 10 of the cutting machine 9,
Next, the can body plate 1 is polished by the polishing wheel 12 of the polishing machine 11.
Polish the welded joint 1c. The purpose of the polishing is to improve the electrical conductivity during electric welding and to perform uniform and reliable welding, so it is sufficient that the joint surfaces have a predetermined level of cleanliness.

The can body plate that has undergone the pretreatment process is subjected to a framing process 13.
After forming a frame through the process, a rectangular cylindrical can body 15 is formed in a body folding process 14, and the joined parts are overlapped by a predetermined width (for example, 3 mm), and are sandwiched between electrodes 16, 16, and electrically applied in a pressurized state. Weld. Various electrodes such as rotating electrodes, wire electrodes, and others are known as the electrodes mentioned above, but there is no need to limit them in particular, and in short, they may be used as long as they have the ability to ensure uniform current conduction during high-speed welding. Can be done. Since the surface of the welded part is damaged by the electric welding, after correcting the inner surface of the welded part by spraying a treatment liquid such as varnish from the nozzle 17, the adhesive applicator 18 is applied to the outer surface of the welded part. Apply the same adhesive as above to the part that will become the seaming edge. In the figure, 19 is a coating wheel.

Next, it is placed in a dryer 20 and dried with hot air at a temperature of about 100 to 120° C. while moving along a curved conveyance path, thereby fixing the adhesive based on the above correction. Next, a flange 22 is provided to the edge of the can body using an edge folding machine 21, and the base plate 23 is wound around one end of the can body with a winding piece 33, and then the top plate 24 is wound around the other end with a winding piece 34, and then airtight. In the testing step 25, products with poor airtightness are excluded and sent to a correction preheating step 26. The can body joint is heated to a can material temperature of about 100 to 120° C. in the correction preheating step 26, then corrected in the welding portion outer surface correction step 27 (for example, by spraying varnish with the nozzle 28), and further heated in the post heater 35. The top and bottom seams are heated to about 190 to 200℃ to melt the adhesive on the seams to ensure airtightness, and the next step 2 is to correct the outer surface of the top and bottom seams.
Perform the pretreatment in step 9. In the outer surface correction step 29, varnish or the like is sprayed from the nozzle 30 to perform external correction of the top and bottom seams, and the metal can product 31 is completed.

(Embodiment 2) Next, the embodiment shown in FIG. 2 is a partially modified version of the embodiment shown in FIG. That is, after the inner surface correction process after electric welding, the flange 22 is dried by putting it in a dryer 20 without performing adhesive correction, and then using an edge folding machine 21 to dry the flange 22.
After that, it is applied to the coating machine 18 and corrected with an adhesive, and then this adhesive is applied to a dedicated dryer 32 to dry it, and the product is obtained through the same steps as described above.

In the embodiment shown in FIG. 1 and the embodiment shown in FIG. 2,
Although there are differences in the before and after processes and in the presence or absence of the dryer 32, it goes without saying that the metal cans and manufacturing methods belong to the same technology. Both embodiments have their own advantages, but the latter corrects the adhesive after the edge is folded, so there is no possibility that the adhesive will peel off during flange processing.
There is no risk of it breaking. In the above, the reason why the adhesive is cut and removed before polishing the can body plate is that the adhesive may not be completely removed depending on the polishing. Further, by applying an adhesive to the can body plate side, a sufficient sealing can be achieved without applying adhesive to the seam portions of the top and bottom plates.

In each of the above embodiments, an adhesive was applied to the can body plate, but instead of the liquid adhesive, an adhesive tape (for example, nylon tape) may be attached and interposed. In this case, there is no need for dry fixing. In other words, the can of the present invention is a metal can in which the can body joint is electrically welded, and the can body and the top and bottom plates are wrapped together using an adhesive.

(Effects of the Invention) That is, according to the present invention, since the adhesive is applied to the can body plate by drying and fixing, there is no fear that the adhesive will adhere to or peel off from various parts during the can manufacturing process. In addition, the joints of the can body were fixed by electric welding, and the edge of the can body and the top and bottom plates were secured by seaming with adhesive, so there was no risk of straining because the seaming part of the joint was only doubled. It is possible to obtain uniform strength as a whole with less (no quadrupling as in the case of seam folding), the strength of the joint is highly reliable, and the seaming part can be processed smoothly. As a whole, there is an effect of obtaining a pollution-free metal can with high strength. In addition, not only the seam folding process of the can body is omitted, but also the soldering process is omitted, which makes it possible to prevent pollution caused by solder. The reliability of the strength of the can body is increased, and in addition, various steps such as applying adhesive to the can body joint, drying it, folding it, and heating and curing the can body joint after can manufacturing can be omitted. This has various effects such as further simplifying and speeding up the can manufacturing line.

In addition, by adding an adhesive correction process and an electric welding part correction process, the poor airtightness of the seaming part of the can body joint, which was considered a problem in the past, has been improved, and the problems caused by using electric welding have been solved. A homogeneous metal can can be obtained with all improvements.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing each step of implementing the manufacturing method of the present invention and the state of materials or semi-finished products in each step, and Fig. 2 is a state diagram of an embodiment in which a part of the process of Fig. 1 is partially changed. be. 1... Can body plate, 2... Slitter, 3... Coating machine, 4
...Adhesive layer, 5...Applying roll, 6...Preliminary dryer,
7... Book dryer, 8... Cooler, 9... Cutting machine, 10...
Cutting blade, 11... Grinding machine, 12... Polishing wheel, 13... Framing process, 14... Body folding process, 15... Can body, 16... Electrode, 17... Nozzle, 18... Coating machine, 19... Coating wheel, 20... Dryer, 21... Edge folding machine, 22... Flange, 23... Base plate, 24... Top plate, 25... Airtightness test process, 26... Correction preheat process, 27... Outer surface correction process, 28... Nozzle, 29... Correction process, 30 ...Nozzle, 31...Product, 32...Dryer, 33, 34...
Winding piece, 35...Post heater.

Claims (1)

[Scope of Claims] 1. Adhesive to the corner of the welded edge perpendicular to the seam edge of a can body plate for a large metal can in which an adhesive is applied to the seam edge between the top and bottom plates and is dried and fixed. After cutting and removing the adhesive, the welded edge is polished and cleaned over a predetermined width, and then the can body plate is framed and bent to form a rectangular tube shape, and the rectangular tube-shaped can body is welded. Overlap the edges by a predetermined width and electrically weld the entire length of the part,
Next, apply varnish or other treatment liquid to the electric weld, then apply adhesive to the upper and lower parts of the weld that will be seamed and dry, and then seal the upper and lower edges of the can body. After folding, the periphery of the top and bottom plates is brought into contact with the folded parts of the top and bottom edges of the can body, and the folded top and bottom edges of the can body and the periphery of the top and bottom plates are sequentially rolled and fixed, thereby forming a connection between the top and bottom plates and the can body. A method for manufacturing metal cans characterized by heating the seaming part to correct the fusion of adhesive. 2. The method of manufacturing a metal can according to claim 1, wherein the adhesive is dried and fixed to the can body plate by preliminary drying, main drying, and then cooling. 3. The metal according to claim 1, wherein the correction of applying adhesive to the upper and lower ends of the welded part is performed immediately after the correction of the electric welding part or after the electric welding correction and its drying process. How to make cans.