JPH0234257B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Application to which the Invention Pertains) The present invention relates to a seamed jointed can and a method for manufacturing the same, and more specifically, the present invention relates to a seamed jointed can and a method for manufacturing the same, and more particularly, the present invention relates to a seamed can which effectively suppresses leakage due to defects called lap cracks in the seamed part, and also improves can manufacturing workability. This invention relates to a markedly improved seamed can and its manufacturing method. (Prior art) Conventionally, when manufacturing cans, a can body with open ends was covered with a can end, and double seaming was performed between the can body flange and the periphery of the can lid. conduct.
As a can body member, a material in which can raw materials (blanks) are joined together on the sides with a bonding agent such as a resin adhesive or solder is widely used. In the double-sealed part between the can body and can lid, the flanged can body end is bent approximately 180 degrees as a whole, and the can is wrapped around this bent can body end. The area around the lid is tightened. At the seamed end of the can body, the two pieces of material naturally overlap at the overlapping seam, and during the seaming process, the material on the inside of the seam of the two joined pieces is axially While receiving a strong tensile force, the material outside the seam receives a compressive force in the axial direction, and a tensile shearing force between the two materials in the circumferential direction. The bonding agent present between the seams is thus subjected to extremely large shearing forces both in the axial direction of the container and in the same direction, causing micro-destructive defects called lap cracks at the joints, which cause leakage over long periods of time. To prevent this, U.S. Patent No. 2,120,038 proposes providing a V-shaped notch that enters the seam from the edge at the overlapping seam of the can body and the can lid. Also, JP-A-55-
55935 proposes applying a similar cutout to an adhesive can. (Problems to be Solved by the Invention) Although the above-mentioned means are effective in alleviating the shearing force applied to the joint portion of the lap seam and preventing so-called lap cracking, it has been recognized that the following drawbacks occur. It will be done. That is, the notch entering the lap seam from the edge creates a discontinuity in the edge, which causes the blanks to engage with each other, often making smooth conveyance and handling of the blanks difficult. Further, it is often difficult to smoothly and efficiently overlap and join the opening side edge portions separated by the notch. Furthermore, since the edges are discontinuous, it is difficult to accurately align the overlapping joint portion on the opening side with respect to the notch portion with the overlapping joint portion on the center side. Furthermore, when manufacturing adhesive cans, both ends of the can material to be joined are heated by high-frequency induction to soften or melt the adhesive layer, and then both ends are overlapped and bumped while cooling. However, when performing high-frequency induction heating, if the above-mentioned notch exists, overcurrent is likely to be induced at the end on the opening side of the notch, causing excessive heating in this part and making it impossible to perform it properly. This is a fatal drawback in industrial production. SUMMARY OF THE INVENTION Accordingly, the technical object of the present invention is to provide a seamed and joined can which prevents lap cracking in the seamed portion and eliminates the above-mentioned drawbacks, and a method for manufacturing the same. Other technical objects of the present invention are that the integrity of the seam joint is excellent, that the seam can be formed easily and with good workability, and that the occurrence of lap cracks can be effectively prevented during seaming. An object of the present invention is to provide a can with a new structure for preventing seaming and joining, and a method for manufacturing the same. (Means for Solving the Problems) According to the present invention, a can body in which can materials are stacked and joined at the sides through a bonding agent, a can lid, and a seaming portion formed between the two, A punched hole is placed in one of the edge parts of the can material to be overlapped and joined, and a punched hole is located within the width of the overlapped joint, and a punched hole is located within the width of the overlapped joint, and a punched hole is located within the width of the overlapped joint, and a punched hole is formed in one of the edge parts of the can material to be overlapped and joined. R ₂ /W = 0.05 to 0.45 ω ₁ ≧0.3mm ω ₂ ≧0.5mm In the formula, R ₂ is the circumferential radius of the punched hole, W is the circumferential width direction of the overlapping joint, ω ₁ represents the bonding width on the outer edge side outward from the hole, and _ω2 represents the bonding width on the inner edge side outward from the hole. A seamed and joined can is provided. According to the present invention, there is also a winding method comprising manufacturing a can body by joining the sides of the raw materials for a can using a bonding agent, and then seaming between the open end of the can body and the can lid. In the method for manufacturing cans, a punched hole is placed in one of the edge parts of the can material to be overlapped and joined, and a hole is punched out within the width of the area where the overlap is to be joined. and the formula R ₂ /W = 0.05 to 0.45 ω ₁ ≧0.3 mm ω ₂ ≧0.5 mm where R ₂ is the circumferential radius of the punched hole, W is the circumferential width direction of the overlapping joint, ω ₁ represents a bonding width on the outer edge side outward from the hole, and ω ₂ represents a bonding width on the inner edge side outward from the hole, respectively; and applying a thermal adhesive to at least one of the edge portions. The process is performed in this order or in the reverse order, and both end portions to be joined are heated by high frequency induction, and the heated end portions are overlapped and pressurized while cooling to form a side seam. A method for manufacturing a seamed and joined can is provided. (Function) In FIGS. 1 and 2 showing the main parts of the jointed can body of the present invention in an enlarged manner, both side ends 2 of the can material 1 are shown.
a and 2b are overlapped and bonded via adhesives 3 and 4 to form an overlapping seam 5. In this specific example, a layer of thermal adhesive 3 made of thermoplastic resin is adhered to the inner surface of the end 2a that is on the outside of the seam, and a layer of thermal adhesive 3 made of thermoplastic resin is also attached to the inner surface of the end 2b that is on the inside of the seam. A layer of thermal adhesive 4 made of plastic resin is bonded so as to wrap around the edge 6. By melting and integrating these thermal adhesives 3 and 4, side overlap bonding is performed. According to the present invention, both ends 2 to be overlapped and joined
a, 2b, in this example, the overlapping joint part 5
A punched hole 7 is provided in a portion that is located within the width (W) of and includes a part of the bent portion (described later) of the seaming portion. The punched hole 7 is, as the name suggests, a punched hole, and the feature of the present invention is that the edge 8 of the end portion 2a is completely continuous even at the hole 7 portion. In addition, since this punched hole 7 is provided within the width of the joint portion 5, there is an appropriate joint width w ₁ and punched hole 7 between this punched hole 7 and the seam outer edge 8.
and the seam inner edge 9 is an appropriate joint width w ₂
is ensured, and leakage through the punched holes 7 is prevented. In the present invention, the edge 8 on the outside of the seam
The continuity is maintained without any notches,
Since the part on the opening side of the punched hole 7 is always integrated with the part below it, the consistency of the seam bonding agent, that is, the consistency with the inner circumferential surface of the can body can be improved. In addition, when transporting and handling can materials during the can manufacturing process, all edges are continuous and there are no notches, so can materials may engage (get caught) with each other. The inconvenience is resolved,
These operations as well as the operation of overlapping and joining both end portions 2a and 2b can be performed extremely smoothly and with good workability. In the part of the joint part 5 where the punched hole 7 is provided, the adhesive 4 is exposed to the outside, that is, one surface thereof is tightly adhered to and restrained by the inner end part 2b; The other surface, that is, the outer surface, is an unrestricted free surface. When sealing the open end of the can body with the can lid, the open end is first bent outward by approximately 90 degrees (toward the front in Figure 1) to form a flange, and then the can lid is sealed. Then, it is further bent approximately 90 degrees downward. As a result of these processes, compressive stress is applied to the outer end 2a in the axial direction as shown by arrow A, as shown in FIG. 3, while compressive stress is applied to the inner end 2b as shown by dotted arrow B. Tensile stress acts in the axial direction. Furthermore, an arrow C is attached to both ends 2a and 2b.
As shown in , tensile stress in the circumferential direction acts. It will be appreciated that correspondingly to these stresses, significantly large shear stresses are generated in the adhesive layers 3, 4. In the present invention, since one surface of the adhesive layer 4 is an unrestricted free surface in the punched hole 7 area, no shear stress is generated in the adhesive layer in this area. First, the circumferential edge 10 of the punched hole 7 follows the stress in all directions and undergoes appropriate deformation, which acts to avoid excessive shear stress from occurring in the adhesive layers 3 and 4. . For example, in response to compressive stress in the axial direction, it will deform into an elliptical shape compressed in the axial direction, and in response to tensile stress in the circumferential direction, it will deform into an elliptical shape expanded in the circumferential direction. It causes deformation. In this way, the punched hole in the present invention easily deforms in response to stress in any direction.
It will be understood that it has an excellent effect of relieving the shear stress of the adhesive layer. Furthermore, since the punched hole 7 has a smooth circumferential edge 10, stress concentration does not occur in a specific part during flanging and seaming, and the strength of the seam to be seamed is relatively increased. One of the advantages is that it is possible to maintain the joints and avoid troubles such as seam breakage during processing. In the present invention, it is clear from the following theoretical considerations that lap cracking is effectively prevented by providing a hole within the width of the overlapping joint and in a portion that includes the bent portion of the seamed portion. Let's become. The area where internal lap cracking of overlap joints becomes a problem is the joint at the tip of the bend, and if the area of this joint is Smm ² and the yield shear stress of the adhesive is τaKg/mm ² , then The strength at which this joint part cracks is expressed by the formula Fa (Kg) = Sτa (1). On the other hand, the yield strength of the can material is σ _Y Kg/
mm ² , its thickness is tmm, and the width of the bent portion is ωmm, the strength at which the can material yields is expressed by the formula Fb (Kg) = σ _Y・t・ω (2). Now, by comparing the strengths of the two, if the formula Fa<Fb...(3) holds, then the seaming operation can be performed without deforming the can material and destroying the joint. Become. In the present invention, by providing the punched hole 7 in the bent part, the width ω of the bent part becomes the formula ω=ω ₁ +ω ₂ <W (4), which allows the bent part to be deformed and joined. It can be seen that damage to the parts can be prevented. When the hole 7 is provided at the outer end 2a, the compressive force causes deformation to increase the thickness, and when the hole 7 is provided at the inner end 2b, the tensile force causes the thickness to decrease. (Preferred Embodiment of the Invention) Structure of Sealed Part In the seamed and joined can of the present invention, the shape of the hole 7 provided in the can material may be any shape as long as the punched edge is smooth, such as a circle or an ellipse. , ellipse, etc. are most suitable, but polygonal shapes with rounded corners, such as triangles, rectangles, rhombuses, squares, pentagons, hexagons, etc., with rounded corners may also be used. The radius in the axial direction of hole 7 is R ₁ and the radius in the circumferential direction is R ₂
Then, the relationship between each dimension is W=ω ₁ +2R ₂ +ω ₂ (5). The diameter R ₂ in the circumferential direction of the through hole 7, which is clear from the above formulas (1) to (5), is such that the yield deformation of the bent portion occurs prior to adhesive failure, and that leakage from the joint is prevented. The integrity of the seams shall be maintained. Generally, R ₂ /W is between 0.05 and 0.45, particularly between 0.10 and
By setting the ratio to 0.35, both of the above requirements can be satisfied. That is, this ratio R ₂ /
If W is smaller than the above range, there is no significant effect on preventing lap cracking, while if it is larger than the above range, there is a tendency that leakage from the seams and integrity of the seams cannot be achieved. Seam width W is generally 1.0 to 10.0mm,
In particular, it is best to set it in the range of 2.5 to 2.5 mm, and the outer edge side joint width ω ₁ should be 0.3 mm or more in terms of joint integrity.
In particular, it should be in the range of 0.5 mm or more, and the inner edge side joint width ω ₂ is 0.5 mm in order to prevent leakage from the joint.
It should be in the range of 1.0 mm or more, especially 1.0 mm or more. The axial diameter R ₁ of the hole 7 is determined so that the yield shear strength Fa of the bonding agent in the area from the bent part to the tip does not decrease too much, and the deformation of the hole 7 during tightening is suppressed.
shall be determined as permissible within That is, when H is the distance from the bent portion to the tip, the ratio R ₁ /H is generally in the range of 0.15 to 0.85, particularly preferably in the range of 0.20 to 0.60. If this ratio R ₁ /H is smaller than the above range, it will be difficult to absorb the deformation that occurs during seaming within the hole 7, which will easily lead to lap cracking, and if this ratio R ₁ /H is smaller than the above range, If it is too large, the yield shear strength Fa of the joint decreases, and as a result, lap cracking is likely to occur. Hole 7
The ratio of R ₁ /R ₂ is between 0.1 and 5, especially between 0.3 and 2.
, and most preferably 1. The joint structure can be any arbitrary joint structure as long as the seamed portion is a lap joint.
For example, it goes without saying that the entire side seam of the can body may be a lap joint, but there may also be cases where only the seam is a lap joint and the other parts are lock joints, or the seam is a lap joint and other parts are lap joints. This also includes the case where the portion of ``wrap'' and ``lock'' alternate. FIGS. 4 and 5 show cross sections of the seam and other parts of the seamed and joined can of the present invention. This can consists of a can body member 11 and a can lid 12,
A double seam portion 13 is formed between the two. In this double-sealed portion 13, the can body member 11 has an extended hook (sealed flange portion) 14, and this can body hook 14 is bent approximately 180 degrees downward from the bent portion 15. , its extreme end 1
6 is located at the bottom. On the other hand, the can lid 12 has a peripheral part 17 which wraps around the hook 14 of the can body member 11, that is, between the outer annular part 18 and the inner hook 19. Sealing is being performed because the hook 14 is being pinched. In the peripheral part 17 of the can lid, the connecting part between the outer peripheral annular part 18 and the can lid hook 19 on the inner peripheral side or the downwardly curved part 20 is located below the lowermost end part 16 of the can body member 11, On the other hand, the tip 21 of the hook 19 on the inner peripheral side is located below the bent portion 15 between the can body member 11 and the can body hook 14. A lower clearance portion (lower gap portion) 22 is provided between the lower curved portion 20 of the can lid and the lowermost end portion 16 of the can body member.
There is an upper clearance portion (upper gap portion) 23 between the tip 21 of the can lid and the bent portion 15 of the can body member. The sealing rubber composition layer 24 almost completely fills the lower clearance portion 22 and also fills the upper clearance portion 23 . FIG. 4 shows an enlarged view of the double side seam in the side seam of the can body member 11. In the can body hook 14 corresponding to this side seam, the two can body metal material ends 2a and 2b are Although it has a structure in which they are joined via a thermal adhesive 3, the above-mentioned bent portion 1
5, it will be clear that the presence of the hole 7 allows the deformation of one end 2a. Can Material In the present invention, any can material can be used as the can material, such as black steel, tin-plated steel plate,
Nickel plated steel plate, tin-nickel plated steel plate,
Various steel plates such as aluminum plated steel plates, stain-free steel, chromium oxide chemically treated steel plates, and light metal plates such as aluminum are used. Among such metal materials, it is desirable to use stain-free steel (TFS) because the present invention is particularly advantageously applied to adhesive cans. In the present invention, any stain-free steel (TFS) material can be used. TFS
The material is known to consist of a steel plate substrate such as a rolled steel plate and a chromium-containing coating layer selected from the group consisting of metallic chromium, nonmetallic chromium, and combinations thereof applied to the surface of the steel plate substrate. This material is preferably used for the purpose of the present invention. The chromium-containing coating layer has a content of 0.06 to 3.6mg/chromium equivalent.
dm ² , particularly those with a film thickness in the range of 0.1 to 2.5 mg/dm ² are generally easily available and suitable for the present invention, but of course there is no need to be limited to this, and aluminum plating Steel plates, electrogalvanized steel plates, cooling steel plates, etc. can also be used depending on the purpose. In addition, the chromium-containing coating layer has particularly excellent corrosion resistance, consisting of a metallic chromium layer on the steel plate substrate and a non-metallic chromium layer (chromium oxide and/or hydrated chromium oxide layer) on the metallic chromium layer. , and the metallic chromium layer is 0.05 to 3.0 mg/dm ² , especially 0.1 to 2.0
mg/dm ² , and the nonmetallic chromium layer has a thickness of 0.01 to 0.6 mg/dm 2 , especially 0.05 to 0.6 mg/dm ² in terms of chromium.
TFS materials having a film thickness in the range of 0.4 mg/dm ² are known, and these TFS materials can also be suitably used for the purpose of the present invention. The can material to be used will generally have a thickness of 0.12 to 0.40 mm, particularly 0.14 to 0.36 mm, although it will vary depending on the purpose of the seamed can. If the thickness of the base material is lower than the above range, changes may occur during the production or storage of canned goods, while if it exceeds the above range, processing such as double seaming tends to become difficult. . Paint A paint is applied to the above metal material for cans to protect it. Generally speaking, such a protective coating film contains polar groups such as hydroxyl groups, ether groups, carboxyl groups, and epoxy groups at a concentration of 10 to 2000 mmol/100 g resin, particularly 20 to 1500 mmol/100 g resin. A thermoplastic resin or a thermosetting resin containing the resin is used. Suitable examples include vinyl chloride-vinyl acetate copolymer paints, partially saponified vinyl chloride-vinyl acetate copolymer paints,
Vinyl paints such as vinyl chloride-vinyl acetate-acrylic acid copolymer paints; organosol paints made by dispersing vinyl chloride resin in the above-mentioned vinyl paints;
Epoxy resin-modified vinyl paint; thermoplastic polyester paint; acrylic paint; epoxy-modified acrylic paint; urethane-modified acrylic paint; epoxy-phenol paint, epoxy-amino resin paint, alkyd paint, thermosetting polyester It is a paint consisting of one or more types of paints. When using an adhesive, especially a nylon adhesive, it is desirable that the protective coating also serves as an adhesive primer, and such adhesive primer and protective coating may include epoxy resins, phenols containing polycyclic phenols, Paints containing aldehyde resins are preferably used. As the epoxy resin component a, all those conventionally used as epoxy resin components in so-called phenol-epoxy paints can be used without restriction, but representative ones include epihalohydrin and bisphenol A [2 ,2′-bis(4-
Examples include epoxy resins having an average molecular weight of 800 to 5,500, particularly preferably 1,400 to 5,500, produced by condensation with [hydroxyphenyl)propane],
This product is suitably used for the above-mentioned purpose of the present invention. As the phenol/aldehyde resin component b used in combination with the epoxy resin component a, any resin can be used as long as it contains a polycyclic phenol in its resin skeleton. As used herein, polycyclic phenol refers to phenols having a plurality of rings to which phenolic hydroxyl groups are bonded, and representative examples of such polycyclic phenols include 2,2'-bis(4-hydroxy phenyl)propane (bisphenol A), 2,2'-bis(4-hydroxyphenyl)butane (bisphenol B), 1,1'-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl) enyl)methane (bisphenol F), 4-hydroxyphenyl ether, P-(4-hydroxy)phenol, etc., but bisphenol A is most preferred. These polycyclic phenols, alone or in combination with other phenols, are subjected to a condensation reaction with formaldehyde to form a resol type phenol aldehyde resin. Other phenols include
All monovalent phenols conventionally used in the production of this type of resin can be used, but difunctional phenols;
For example, o-cresol, p-cresol, p-
Most preferred is one or a combination of two or more difunctional phenols such as tert-butylphenol, p-ethylphenol, 2,3-xylenol, and 2,5-xylenol. Of course, in addition to the above bifunctional phenols, trifunctional phenols such as phenol (coals), m-cresol, n-ethylphenol, 3,5-xylenol, and m-methoxyphenol; 2,4-xylenol, Monofunctional phenols such as 2,6-xylenol; p-tert
-aminophenol, p-nonylphenol, p
Other difunctional phenols such as -phenylphenol, p-cyclohexylphenol, alone or in combination with the above difunctionalities, can also be used in the preparation of phenolic aldehyde resins. The amount of polycyclic phenol in the phenolaldehyde resin may be at least 10% by weight or more, particularly 30% by weight or more of the total phenol components, but if the polycyclic phenol (a) and the monovalent phenol (b) are B = 97:2 to 65:35 It is especially advantageous in terms of retort resistance to combine at a weight ratio of 95:5 to 75:25. The resol type phenol aldehyde resin used in the present invention is obtained by reacting the above-mentioned phenol and aldehyde in the presence of a basic catalyst. There is no particular restriction on the amount of aldehyde to phenol, and it can be used in the ratio conventionally used in the production of resol type resins, for example, a ratio of 1 mol or more, particularly 1.5 to 3.0 mol, per 1 mol of phenol. aldehydes can be suitably used, but there is no particular disadvantage in using less than 1 mole of aldehyde. It is generally desirable to carry out the condensation in a suitable reaction medium, especially an aqueous medium. As the basic catalyst, any of the basic catalysts conventionally used in the production of resol type resins can be used. The aforementioned epoxy resin component a and phenol aldehyde resin component b can be used in combination in any ratio within the range conventionally used in these various paints, and are not particularly limited. From the viewpoint of retort resistance of the bonded part, it is preferable to use a paint that combines the two in a weight ratio of (a):(b)=95:5 to 50:50, particularly 90:10 to 60:40. Bonding agent In the present invention, any bonding agent conventionally used for side overlap bonding, such as solder, thermoplastic or thermosetting resin adhesive, etc., can be used as the bonding agent. (hot melt type)
It is most preferred to use a thermoplastic resin adhesive. Suitable examples of hot melt adhesives include, but are not limited to, polyamides, polyesters, ionomers (ionically crosslinked olefin copolymers), acid-modified polyolefins,
These include vinyl ester copolymers and copolycarbonates. An example of a suitable polyamide adhesive is 100 carbon atoms.
At least one type of nylon having amide groups in the range of 4 to 12, more specifically, poly-ω-aminodecanoic acid, poly-ω-aminoundecanoic acid, poly-ω-aminoundecanoic acid, dodecanoic acid,
Poly-ω-aminotridecanoic acid, polydecamethylene sebamide, polydecamethylene dodecamide, polydecamethylene tridecamide, polydecamethylene adipamide, polydodecamethylene sebamide, polydodecamethylene dodecamide, poly Dodecamethylene tridecamide, polytridecamethylene adipamide, polytridecamethylene sebamide, polytridecamethylene dodecamide, polytridecamethylene tridecamide, polyhexamethylene azelamide,
Examples include polydecamethylene azeramide, polydodecamethylene azeramide, polytridecamethylene azeramide, and the like. These polyamides can be used in the form of a blend of two or more types, a copolyamide consisting of a combination of each monomer, or a combination of these in the form of a blend. The polyamide used may be modified with a different component such as a dimer acid in a small amount. Suitable examples of polyesters which can be used are high molecular weight copolyesters, in particular polymeric copolyesters containing terephthalic acid units and other dibasic acid units as the diol component and tetramethylene glycol units as the diol component; and/or a high molecular weight copolyester containing benzene dicarboxylic acid units as a dibasic acid component and tetramethylene glycol units and other diol units as a diol component, specifically, polytetramethylene terephthalate. /isophthalate, polytetramethylene terephthalate/isophthalate/adipate, polytetramethylene terephthalate/adipate, polytetramethylene terephthalate/sebatate, polytetramethylene/ethylene terephthalate, polytetramethylene/polyoxyethylene terephthalate, poly Examples include tetramethylene/polyoxyethylene terephthalate/isophthalate. In addition to being used alone, these copolyesters are also used as a blend of multiple types, and are also used in combination with polyethylene, polypropylene, ionomers,
A part of polyolefin resin such as ethylene vinyl acetate copolymer and modified polypropylene may be blended and used. Ionomers include resins obtained by neutralizing copolymers of olefins and unsaturated carboxylic acids or other vinyl monomers with alkali metals, alkaline earth metals, or organic bases, such as those commercially available from DuPont in the United States. Surlyn types are used. Furthermore, polyolefins such as polyethylene, polypropylene, and crystalline ethylene-propylene copolymers are added with ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and ethylenically unsaturated carboxylic acids such as maleic anhydride and itaconic anhydride. An acid-modified polyolefin obtained by graft polymerization with a saturated carboxylic acid may be used. Furthermore, as vinyl ester copolymers, copolymers of vinyl esters and olefins or other vinyl monomers, or partially saponified products thereof, such as ethylene/vinyl acetate copolymers, partially saponified ethylene-vinyl acetate copolymers, etc. , vinyl chloride/vinyl acetate copolymers may be used. The thermoplastic resin used in the present invention should have a sufficiently high molecular weight, and it is generally desirable to have a number average molecular weight of 6,000 or more, particularly 9,000 to 500,000. In addition, from the viewpoint of heat-fusibility and ease of heat-bonding operation, this resin is suitable for temperatures ranging from 80 to 280 degrees Celsius, especially from 90 to 240 degrees Celsius.
It is desirable to have a softening point (melting point) of °C. Can Making Operation The manufacturing operation can be carried out by any method known per se, except for providing the holes 7 described above. When making cans, the paint described above is first applied to a metal material and baked to produce a coated metal material. The thickness of the coating film is generally 0.5 to 20μm, especially 1 to 20μm.
It is preferable that it be in the range of 10 μm. In Figure 6-A, which shows the order of processing from this painted metal material, an adhesive layer 4 is applied to the end 2b of the painted metal material 1 that should be inside the seam so as to wrap around the cut edge, and then An adhesive layer 3 is also applied to the surface to be overlapped with the end portion 2a which is to be the outer side. The thickness of the adhesive layers 3 and 4 is generally between 10 and 300 μm, particularly between 15 and 150 μm.
The width (W) of the adhesive layers 3 and 4 is preferably larger than the width (W) of the overlapping seam. Adhesive application is facilitated by applying a preformed adhesive tape to the heated edges of the painted metal stock and thermally bonding. The painted metal material coated with this adhesive is cut into a size that corresponds to the height of the can body to create can material (blank).
shall be. Next, in FIG. 6-B, a hole 7 is formed by punching in the end portion 2a on which the adhesive layer 3 is applied. The position where the hole 7 is formed is the position already described. It is preferable to provide the hole 7 at the end 2a of the material to be joined, and to provide sliver notches 30 at the upper and lower edges of this end. This sliver notch 30 serves to prevent the hook corresponding to the overlapping joint from becoming too thick in the seaming part, and also to prevent misalignment between the ends. It will be obvious to those skilled in the art that the holes 7 can be formed by punching prior to applying the adhesive layer 3. Next, the can material shown in FIG. 6-B is rolled up, both ends with the adhesive layer in a molten state are overlapped, and bumped while cooling to create the can body shown in FIG. 6-C. After forming the can body in this way and performing neck-in processing in one or more stages as necessary,
Flange processing is performed, and finally the can lid is sealed with a can lid coated with a sealing compound to form the final can. For the can lid, the above-mentioned can material is press-molded, and if necessary, easy-open lid processing is performed.
As the sealing compound, a material lined with styrene-butadiene rubber latex or the like is used. (Example) The present invention will be explained with the following example. Example 1 Epoxyphenol paint was roll-coated on both sides of a large electrolytic chromic acid-treated steel plate TFS with a thickness of 0.17 mm, a length of 827 mm, and a width of 1026 mm, and baked, and then the surface of this plate that was to become the inner surface of the can was coated with a roll. When the strip is cut into strips with the width of the can body circumference described later, a width of 2.0mm on one side and 5.5mm on the other side is left from the edge along the longitudinal direction, and the other surfaces are painted with a margin and baked. Further, on the surface of this board that was to become the outside surface of the can, printing and finishing varnish were applied in the usual manner, leaving a width of 5.5 mm on one side from the edge along the longitudinal direction when the strip was cut into strips in the same manner as above. . This large board was cut to a width of 170.40 mm along the painting direction using a regular cutting machine.
mm, cut into strips with a length of 827 mm. Both ends along the length of this strip are preheated to about 270°C with a width of about 7 to 8 mm using high-frequency heating, and a tape of nylon adhesive film with a thickness of 40 μm and a width of 6 mm is attached to one end of the strip. The strip is rolled and crimped along the edge to the side that is to be the adhesive on the inside of the can, then cooled, and at the same time, the adhesive tape on the outside of the can is applied to the other end of the strip using a piece of tape with a width of 8 mm. The strip was crimped with rolls in the same manner, 5 mm on the surface that was to become the inner surface of the can, 2.5 mm on the surface that was to become the inner surface of the can, and the cut end surface of the strip was protected, and then cooled. In this case, the adhesive tape width of 2.5 mm was placed at the end of the strip where the width of the uncoated area of the top coat layer was 2.0 mm. With the adhesive tape thus applied, the strip was further cut at right angles to form a 136.52 mm x 170.40 mm can blank with adhesive tape at both ends. At the end of this can blank that has the surface that is to become the can inner side joint (commonly called the outside because it is the side that will become the outside of the can after joining), at a distance of 2.5 mm from the end surface and the can Two round holes with a diameter of 2 mm were formed using an ordinary punch and die at two locations centered at 2.4 mm from both end faces in the height direction. Further, adjacent to this round hole, a notch was formed by cutting off the corner of the can blank along a diagonal line connecting points 0.5 mm along the height direction of the can and 2.7 mm along the circumferential direction. On the other hand, we decided to provide a commonly used notch at the end of this can blank that has the surface that is to become the outer joint of the can (commonly known as the inside).
A corner cut was made along a diagonal line connecting 1.1 mm and 3.3 mm points along the circumferential direction. The dimensions of the part with the punched holes were as follows. R ₁ = R ₂ = 1 mm, W = 5 mm R ₂ /W = 0.2 ω ₁ = ω ₂ = 1.5 mm H = 2.4 mm R _{1 /} H = 0.42. The thus produced can blank with punched holes according to the present patent example was formed into a cylindrical shape using an ordinary can making machine so that the height of the can was 136.52 mm, and adhesive tape was applied. The coated ends were heated to 250°C by high-frequency heating, and the ends were overlapped with a width of 5 mm so that the adhesive overlapped with each other, and the can bodies were crimped while cooling to produce a can body. The outer diameter of this can body is approximately 53 mm, but this can body was further processed with a neck-in process using a commonly used die, and the outer diameter of the portion where the can lid is wrapped was approximately 50.5 mm. . Next, after performing flange processing using a commonly used method, a regular 200-diameter aluminum lid obtained by punching and forming an aluminum coated plate as a bottom lid and applying and drying an SBR water base compound is processed using a regular method. The empty can product of Example 1 was then double-sealed at one end of the can body. Comparative Example 1 A can blank measuring 136.52 mm x 170.40 mm having adhesive tape on both ends was produced in exactly the same manner as in Example 1. At the end (commonly known as the outside) of this can blank that has the surface that is to become the inner side joint of the can, the corners of the blank are 1.0 mm along the height direction of the can and 4.0 mm along the circumferential direction. The usual sliver notch was created by cutting off along the diagonal line connecting the points. On the other hand, a commonly used notch is provided at the end of the can blank having the surface that is to become the can outer surface joint, as in Example 1.
1.1mm along the height direction of the can, along the circumferential direction
Corners were cut along a diagonal line connecting the 3.3 mm points. The blank provided with this sliver notch was molded and bonded using a commonly used can making machine similar to that in Example 1 to produce a can body, and was further subjected to neck-in processing and flange processing in the same manner as in Example 1. The empty can product of Comparative Example 1 was also made by double seaming the same 200 diameter aluminum lid as in Example 1 to one end. Example 2 A tin plate with a thickness of 0.23 mm was cut into a size of approximately 170 mm x 136.5 mm to form a can body blank. As will be described later, the can produced from this blank is a so-called solder can, which is manufactured by soldering the joints.
The joint part of the solder can is different from that of the so-called adhesive can using thermoplastic resin as detailed in Example 1.
Except for the part on both ends of the can body where the lid is seamed, one end of the blank is usually bent outward, while the other end is bent inward, and after the two are engaged, the engaged part is crimped. However, the structure is such that molten solder is then poured into this part to complete the joining. Due to this bending process, the shape of the blank is not a simple square, unlike in the case of so-called adhesive cans.
One end extends like a tongue, and the other end, which should engage with this tongue, is generally slitted. This shape should be described in detail in Example 2, but the details are well known to those skilled in the art and have nothing to do with the essence of this patent, so it is unnecessarily complicated. I will omit certain details. Just to be sure, even though the can body part that does not undergo the seaming process has such a complex shape, the parts at both ends of the can body where the lid is seamed, which is related to this patent, The shape is exactly the same as that of a so-called adhesive can, and conceptually the shape after being soldered by a normal can making machine is that the adhesive layer of the thermoplastic resin in the adhesive can is replaced by solder. It is safe to assume that there are layers. Note that the parts of this blank other than those to become the solder joints, both the inner and outer surfaces of the can, are roll coated with epoxyphenol paint and baked. In the part of the can blank to be seamed, at the end (commonly known as the inside) that has the surface that is to become the can outer surface joint, at a distance of 2.5 mm from the end surface and in the height direction of the can. from both end faces of
The major diameter is 2.6 mm at two locations centered around the 2.4 mm position.
An elliptical hole with a minor axis of 1.8 mm was formed using an ordinary punch and die in such a direction that the major axis was parallel to the edge of the can in the height direction. Furthermore, adjacent to this oval hole, cut the corner of the can blank along the height direction of the can.
A notch was made by cutting off a diagonal line connecting 0.5 mm and 2.8 mm points along the circumferential direction. On the other hand, in the part of the can blank to be seamed, a commonly used notch is provided at the end (commonly known as the outside) that has the surface that is to become the can inner surface joint. 1.2mm along the height direction of
5.1 measured from the outer diameter of the blank along the circumferential direction
A square cut was made using a diagonal line connecting the mm points. The dimensions of the part with the punched holes were as follows. R ₁ = 1.3mm R ₂ = 0.9mm W = 5mm R ₂ /W = 0.18 ω ₁ = 1.6mm ω ₂ = 1.6mm H = 2.4mm R ₁ /H = 0.54 Example of the present patent produced in this way A can blank with punched holes is formed into a cylindrical shape with a can height of 136.5 mm using an ordinary can making machine, and the can blank is formed into a cylindrical shape with a can height of 136.5 mm. The tongue-like part and the part inside the slit section at the other end are bent in opposite directions and then interlocked and crimped, and the part that is not subjected to seaming process and the part that is subject to seaming process. After preheating the entire joint including both with a gas burner, molten all-tin solder was infiltrated, and then cooled to produce a can body. Next, the can body was flanged using a commonly used method, then a bottom cover was stamped out of an aluminum coated plate, and an SBR water base compound was applied and dried to create a regular 202 diameter aluminum cover. An empty can product of Example 2 was obtained by double seaming one end of the can body using a conventional method. Comparative Example 2 A thickness of 0.23 was obtained using the same method as in Example 2.
A can blank of approximately 136.5 mm x 170.0 mm with tongue-shaped portions and slit portions at both ends was prepared from a tin plate steel plate of 136.5 mm x 170.0 mm. In the part of this can blank to be seamed, at the end (commonly known as the inside) that has the surface that is to become the outer joint of the can, the corner of the blank is 1.2mm along the height direction of the can. , 3.5mm along the circumferential direction
The usual sliver notch was created by cutting off along the diagonal line connecting the points. On the other hand, the end of this can blank having the surface that is to become the can outer surface side joint part is also provided with a commonly used notch as in Example 2, with a notch of 1.2 mm along the height direction of the can. , a diagonal cut was made along the circumferential direction along a diagonal line connecting points 5.1 mm apart from the outer diameter of the blank. The blank provided with this sliver notch was molded and soldered using a commonly used can making machine similar to that in Example 2 to produce a can body, which was then subjected to flange processing similar to that in Example 2. An empty can product of Comparative Example 2 was also obtained by double-sealing the same 202 diameter aluminum lid as in Example 2 to one end. Experiment 1 A staining solution was prepared by melting 0.5 g of dye methyl violet in 100 c.c. of butyl cellosolve. After preparing 20 cans each of the above sample, Example 1, and Comparative Example 1 and pouring this dye into the cans, apply epoxy to the inner and outer surfaces of the empty cans at the ends of the empty cans whose lids have not yet been tightened. A 200-diameter TFS lid is punched out using a regular lid punching machine from an electrolytic chromic acid treated steel plate that has been baked with a urea paint and then coated with an SBR sealing compound.The resulting 200-diameter TFS lid is double-sealed using a regular seaming machine. A test can was prepared. Furthermore, the above samples, Example 2, and Comparative Example 2 were each
After preparing 20 cans and pouring this dye into the cans, apply it to the end of the empty can whose lid has not yet been tightened.
A 202-diameter tin lid is punched out using a regular lid punching machine from a tin plate whose inside and outside surfaces are coated with epoxy phenol paint and baked, and an SBR sealing compound is applied.The resulting 202-diameter tin lid is double wrapped using a regular seaming machine. A test can was prepared by tightening the tube. A lid was double-sealed on both ends, and a 6 mm diameter hole was drilled into the body of the test can filled with the dye solution using an ordinary electric drill.
While being careful not to spill the contents, insert an outer diameter of 6 into this hole.
After inserting a mm copper pipe, it was fixed with epoxy adhesive to form a pressure port. A commercially available pressurized tester capable of obtaining a predetermined water pressure by moving a handle to reciprocate a piston was prepared, and the interior of the piston cylinder of this tester was also filled with the dye solution. Next, the pressurizing port of the test can and the discharge port of the pressurizing tester were connected with a nylon tube to complete the piping. Move the handle of the pressure tester to inside the test can.
A pressure of 8.5×10 ⁵ Pa was applied, held for 30 minutes, and then returned to normal pressure. After removing the piping, the can was opened in the usual manner and the dyeing solution contained therein was washed away, and then the can was dried in a constant temperature room at 50° C. for 24 hours. The double-sealed joint is cut out using a scroll saw, and then carefully dismantled under a microscope using a dental technician's electric file to create the double-sealed joint. The cracks were observed depending on the degree of penetration of the staining solution. Results of Experiment 1 The number of test cans was 20 each, but the lid was wrapped around both ends of the can body, and as described in the example, the punched holes featured in this patent were applied to both ends. The results were as shown in the table below.

[Table] As is clear from the results, the overlapping portion provided with punched holes according to the present invention shows no cracking at all even after being tightened, and is superior to conventional cans. In addition, in the process of producing this test can, ordinary can making machinery could be used without any major changes, and the productivity was proven to be comparable and superior to conventional cans. Experiment 2 Prepare 990 cans each of the above samples, Example 1 and Comparative Example 1, put a citric acid aqueous solution containing sugar and sodium bicarbonate powder into the cans, and adjust the gas volume after filling. It was adjusted to be 4.0 at room temperature. After pouring these liquid contents, a regular lid punching machine is used to punch out an electrolytic chromic acid treated steel plate with epoxy urea paint baked on the inside and outside of the can, on the end of the empty can where the lid has not yet been tightened. A test can was prepared by double-sealing a 200-diameter TFS lid obtained by applying SBR-based sealing compound using a normal seaming machine. These test cans were stored in a constant temperature room at 50° C. for one month, and it was observed whether the contents permeated the outer surface of the can by passing through the rolled-up joint. Results of Experiment 2 Cans that have already leaked due to excessive internal pressure are identified by the solidification of sugar on the outside of the can near the seamed lap joint. The results after storage for one month were as shown in the table below.

[Table] The sealing ability of a can is largely determined by the sealing compound applied to the lid, which can be said to be sufficient under normal conditions. However, it is also true that under severe conditions such as in this experiment, even greater differences become apparent.
As is clear from these results, the seamed and joined can of the present invention has an even better sealing ability at the seamed joint than the conventional can.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view showing a specific example of a joined can body according to the present invention. FIG. 2 is a partial cross-sectional view of a lap joint according to the invention. Figure 3 is for explaining the stress state acting on the can material and the adhesive layer.
Partial slope view and enlarged cross-sectional view of the joint. FIG. 4 and FIG. 5 are cross-sectional views of double seaming of a joint portion and a portion other than the joint in a joined can according to the present invention. 6th-A
6-B and 6-C are process diagrams showing the processing order of the present invention. Reference number 1 is the can material, 2a and 2b are the ends of the can body, 3 and 4 are the adhesive layers, 5 is the overlapping joint, and 7
1 is a punched hole, 9 is an inner edge, 10 is a circumferential edge, 11 is a can body member, 12 is a can lid, 13 is a double seam portion, 14 is a can body hook, 19 is a can lid hook, 2
2 is a lower clearance part, 23 is an upper clearance part, and 24 is a sealing rubber composition.

Claims (1)

[Scope of Claims] 1. A seamed-jointed can comprising a can body whose sides are joined together using a bonding agent, a can lid, and a seamed part formed between the two: A punched hole is formed in one of the edge portions of the materials to be overlapped and joined, and the hole is located within the width of the overlapped joint, includes at least a part of the bent part in the seaming part, and has the formula R ₂ /W=0.05~0.45 ω ₁ ≧0.3mm ω ₂ ≧0.5mm In the formula, R ₂ is the circumferential radius of the punched hole, W is the circumferential width of the overlapping joint, and ω ₁ is the outer edge outside the hole. A side joint width, ω ₂ represents a joint width on the inner edge side outward from the hole, and the punched hole is provided as a shear stress relaxation mechanism for the adhesive. . 2. The seamed and bonded can according to claim 1, wherein the bonding agent is a thermal adhesive made of a thermoplastic resin. 3. The seamed and joined can according to claim 1, wherein a sufficient joint is ensured between the punched hole and the inner edge of the seam and the outer edge of the seam. 4. In a method for producing a seamed and bonded can, which comprises manufacturing a can body by overlapping and bonding the sides of can materials using a bonding agent, and then seaming between the open end of the can body and the can lid. , A punched hole is formed in one of the edge portions of the can material to be overlapped and joined, so that the hole is located within the width of the area to be overlapped and joined, and includes at least a part of the area where the seam is to be bent. And the formula R ₂ /W = 0.05 to 0.45 ω ₁ ≧0.3mm ω ₂ ≧0.5mm In the formula, R ₂ is the circumferential radius of the punched hole, W is the circumferential width of the overlapping joint, and ω ₁ is the distance outside the hole. and _ω2 represents the joint width on the inner edge side of the outer edge of the hole, respectively, and the step of applying thermal adhesive to at least one of the edge portions in this order. Alternatively, the process is performed in the reverse order, and both end portions to be joined are heated by high-frequency induction, and the heated end portions are overlapped and pressurized while cooling to form a side seam. Manufacturing method.