JPS6233701Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a metal container having a strong circumferential overlapping seam, particularly a bottle-shaped metal container, and also relates to a metal container that is easy to fit and join. That is, the present invention is formed by stacking and joining a lower body made of a metal cup-shaped molded body and an upper body made of a metal cup-shaped molded body with their open ends, is a metal container in which a spout is formed with a diameter smaller than that of the side wall of the container, and the open end of the lower body is narrowed by neck-in processing so that the diameter is smaller than that of the side wall of the container, and the spout is formed from a vertical cylinder. The open end of the upper body faces an outer seam consisting of a vertical cylinder, and the outer seam is at least 0.2 mm in diameter larger than the inner wall of the outer seam. spreads to 1/100 to 2
It has a curvature surface with a curvature of mm ^-1 , and the overlapping joint between the inner seam and the outer seam is achieved by fusion using a thermoplastic adhesive layer interposed between these two seams. The present invention relates to a metal container characterized by: An upper body and a lower body, which are cup-shaped molded bodies formed by drawing or drawing and ironing of metal materials, are lap-joined at the circumferential open ends, and the circumferential side seams are joined. The formed bottle-shaped metal containers have many advantages over so-called can-shaped metal containers. Among conventional metal containers for packaging, those called three-piece cans have a can lid double-sealed to the top and bottom of the can body, which has side seams, to form a sealed part, and those called two-piece cans In this case, a sealed portion is formed by double seaming between the open end of a cup-shaped can body formed by drawing or drawing-ironing a metal material and the can lid. However, such a double-sealed metal container is subject to major limitations in terms of pressure resistance of the sealed portion and in terms of saving the metal material. That is,
In double-sealed joints, the material that makes up the joint deforms first due to the load applied to the joint, and this deformation causes joint leakage and joint failure to occur with relatively small loads. . In order to prevent this, the material itself must be considerably thicker. In addition, in packaging containers, it is always required to make the metal material used thinner, both from the standpoint of economy and from the standpoint of reducing the weight of the container, but when making the container body wall thinner, there are two There is a problem in that buckling is likely to occur due to loads applied in the axial direction of the container during heavy seaming processes or preparatory processes such as flange processing. A metal bottle made by lap-joining an upper body and a lower body each made of a cup-shaped molded body at their open ends will not cause any deformation of the material at the seam, even if the material forming the seam is extremely thin. figure,
It is possible to withstand up to the shear strength of the seam, which is independent of the thickness of the material, and since there is no need for a seaming process, it has the advantage that the side wall of the container can be made thinner without fear of buckling. However, when the upper and lower bodies are lap-jointed at their open ends to form a circumferential side seam, there are several problems that are different from the case of ordinary can body lap-joints. In other words, in the case of a straight lap joint of the can body, both ends of the joint are mechanically fixed by seaming to the can lid, but in the case of the circumferential side joint described above, the joint is secured all around the entire circumference. Since there is no mechanical fixation across the joint, dimensional deformation of the seam itself is likely to occur easily. Furthermore, since the diameter of the open end tends to change due to temperature changes, stress is likely to occur in the adhesive layer. Furthermore, when bonding with a straight lap joint, it is easy to apply the necessary pressing force to the overlapping portion that becomes the joint, but in the case of a joint where cups are fitted together,
It is difficult to apply the pressing force necessary for adhesion. At this time, due to the dimensional difference between the outer diameter of the inner end of the joint and the inner diameter of the outer end of the joint,
When a pressing force is generated in the adhesive layer, it becomes increasingly difficult to fit these open ends together by pushing them together, and even if forced fitting is performed, the adhesive strength, sealing performance, pressure resistance of the seam, or these problems may be affected. This tends to cause drawbacks regarding the durability of properties. Therefore, an object of the present invention is to manufacture a metal container having the above-mentioned circumferential side seam, so that the open ends can be easily fitted together, the adhesive strength and sealing properties are excellent, and the mechanical strength of the seam can be improved. There is also an improved container to offer. Another object of the present invention is to provide a metal container having a circumferential seam that has a uniform adhesive force over the entire circumference of the seam and is free from leakage over time. The present invention will be explained in detail below. In FIGS. 1 and 2 showing an example of the metal container of the present invention, this bottle has a lower body 1 made of a seamless cup-shaped molded body made of metal such as a tin-plated steel plate, other surface-treated steel plate, or aluminum plate. , and an upper body 2 consisting of a seamless cup-shaped molded body made of metal. It is integrated into the shape of the container by forming a seam 5. In this embodiment, the lower body 1 is a cup consisting of a tall thin side wall 6 formed by highly drawn and ironed metal material and a thick bottom 7 that has not been substantially ironed; On the other hand, upper body 2
is a short side wall 8 formed by shallow drawing of metal material.
It is a cup consisting of a top wall 9 and a top wall 9. The side wall 8 of the upper body 2 is a vertical cylinder whose height is equal to or slightly larger than the width of the seam 5. The upper wall 9 of the upper body 2 has an upwardly convex tapered surface, and a spout 10 for filling or taking out the contents is formed in the center thereof. It will thus be clear that the upper body 2 is joined onto the lower body in the form of a so-called shoulder and neck of a bottle. According to the present invention, the part that is outside the circumferential side seam, that is, the open end 4 of the upper part 2 in the figure, is arranged so that it expands outward with a curvature from the vertical inner wall part 8 of the upper part 2. Create. Furthermore, as shown in FIG. 1, the open end portion 3 of the lower body 1 is necked in at a portion adjacent thereto, so that a vertical portion having a smaller diameter than the other body wall portion 6 is formed through the neck portion 11. Squeeze it to form a cylinder. At least one of the open ends of the lower body 1 or the upper body 2 to be joined, in the figure, the lower body 1
A thermoplastic adhesive layer 12 is provided on the open end 3 of the , and when the adhesive layer 12 is solidified, the open end 4 that is on the outside of the seam is connected to the open end 3 that is on the inside of the seam. This fitted part, that is, the overlapping part, is heated to melt the adhesive layer 12,
Then, by cooling the upper body 2 and the lower body 1
Glue and fix. If the upper body 2 and the lower body 1 are fitted together while the adhesive is in a molten state, the adhesive layer is likely to sag, making it difficult to achieve uniform adhesion over the entire circumference. In addition, when the adhesive is in a fluid and molten state, it is difficult to join them concentrically even if the joining ends are inclined. In contrast, the present invention achieves the best fitting without scraping off the adhesive layer when the adhesive layer is rather solid, and also allows the fitting to be done concentrically. This is based on the knowledge that this is possible. Moreover, according to the present invention, since the parts are joined at concentric cylindrical parallel parts, uniform adhesion can be obtained without causing any difference in the pressing force even if the parts are shifted in the vertical direction due to variations in height. In FIG. 3 illustrating how to fit the open end 4 of the upper body 2 to the outside of the open end 3 of the lower body 1, the open end 4 of the upper body 2 has an outwardly expanding curvature. The inner surface 13 has an inner surface 13. Therefore, the inner diameter of the vertical surface 14 of the end 4 of the upper body 2 is D ₂ , the outward expansion dimension (increase in diameter) of the tip 15 of the surface 13 having the curvature is n, Open end 3
When the outer diameter of the open end 3 is D ₁ and the thickness of the adhesive layer 12 provided on the outside of the open end 3 is d _A , each of these members has the following formula D ₂ +n>D ₁ +2d _A ...(1 ) D ₁ +2d _A > D ₂ ...The dimensional relationship is such that the relationship (2) holds. According to the present invention, by providing the surface 13 having an outwardly expanding curvature on the inner surface side of the open end 4, which is the outer side, the cup-shaped molded body can be easily fitted, has good adhesive properties, and can prevent deformation of the joint. Significant advantages are achieved. That is, by forming the above-mentioned outwardly expanding curvature surface 13, the tip of the inner open end portion 3 comes into contact with this outwardly expanding curvature surface 13 when the two cup-shaped molded bodies are fitted together. After that, the two open ends are guided along this plane by sliding smoothly to a position where they are sufficiently overlapped, and the two can be easily fitted together without using any special equipment. . In particular, by providing this outwardly expanding curvature surface 13, even if the open end 3 of the part 1 on the inside of the joint is slightly deformed from a perfect circle, the open end of both parts Even if there is a slight deviation in the axis, the curved surface 13 of the outer part 2 itself acts as a guide, and the two parts can be easily and smoothly fitted together. When joining circumferential open ends together via an adhesive layer, in order to provide adhesive force to the joint, thermal bonding must be performed under conditions that create an appropriate pressing force between the open ends. As mentioned above, it is necessary to do this. According to the present invention, the above formula (2)
As shown in , even when the dimensions of each member are such that a pressing force is applied to the intervening adhesive layer 12, the two parts can be fitted together very easily, making it possible to form a seam with excellent adhesive strength. becomes possible. Moreover, according to the present invention, since the inner surface of the open end of the outer body is made into a surface with curvature, it is possible to prevent damage to the mating surface and without deforming the open end. Fitting and adhesion are possible, and a container with uniform adhesive force over the entire circumference of the seam can be obtained. In other words, in containers whose open edges are glued together in a deformed state, the seam tends to deform into a circular shape when internal pressure is applied, and this creates large stress in the adhesive layer, resulting in long Problems such as adhesive deterioration and leakage are likely to occur over time, but in this invention, even if the open end has become extremely thin due to drawing and ironing, it is possible to Deformation is prevented, and adhesive deterioration and leakage over time are prevented. Furthermore, if the inner wall of the outer part or the outer wall of the inner part is scratched, the protective coating on the metal material will peel off, and the metal will be directly bonded to the adhesive layer in this area. However, the adhesive force between the metal and the thermal adhesive layer is much smaller than when the two are bonded through a protective coating.
The occurrence of such scratches also causes adhesive deterioration and leakage, but according to the present invention, such causes are also eliminated. Furthermore, in the present invention, forming a surface 13 with a diverging curvature at the open end of the outer part brings about a significant advantage in making the seam stronger. That is, by creating a structure in which the open end is bent, the rigidity of the outer open end 4 and, therefore, the rigidity of the joint 5 as a whole becomes extremely high, and the joint 5 as a whole has a structure that is extremely strong against deformation. .
That is, according to the present invention, not only can the final joint shape be made into a perfect circle or nearly a perfect circle, which is desirable for preventing adhesive deterioration and leakage over time, but also when the two parts are fitted together, There is also an advantage that the inner end of the member is prevented from being deformed, and if the end of the member is already deformed, the effect of correcting it to a perfect circle can be obtained more effectively. In the present invention, as shown in more detail in FIG. 4, corresponding to the curved surface 13 of the outer body 2,
Adjacent to the open end 3 of the inner body 1 is a neck portion 11.
, the above-mentioned effects are further enhanced. That is, due to the presence of this neck portion 11, the rigidity of the seam 5 is further increased, and the seam 5
The deformation prevention function is further increased. Furthermore, the adhesive layer 12 interposed between the open ends 3 and 4 is pressed between the tapered or curved surface 13 and the neck portion 11 due to the axial load applied during fitting or joining. The adhesive strength can be significantly increased in this part of the seam 5. Furthermore, by engaging the curved surface 13 and the neck portion 11 via the adhesive layer 12, the two are always fitted at a constant position, resulting in a container with a constant height. Additional benefits are also achieved. In the present invention, when the expansion dimension n of the outer end of the part is smaller than 0.2 mm, it becomes difficult to achieve the above-mentioned advantages regarding the fitting operation, and the degree of improvement in the rigidity of the joint becomes small.
It is particularly desirable that this extension dimension is in the range of 0.6 to 2.0 mm, and the outer diameter of the outer tip 16 should not be larger than the side wall 6 of the inner body 1. That is, if the outer tip 16 protrudes beyond the side wall 6, there is a risk of damaging other containers or causing injury. Also, the curvature (1/R) of the surface 13 expanding outward
It is also important for the purpose of the present invention that the value be in the range of 1/100 to 2 mm ^-1 , particularly 1/20 to 1/2 mm ^-1 . If the curvature is smaller than the above range, the effect of improving rigidity tends to be reduced, and on the other hand, during adhesion, the number of parallel parts at the seam decreases, which is unfavorable in terms of adhesive strength. On the other hand, if the curvature is larger than the above range, the outer tip 16 of the upper body 2 will appear to be floating above the shoulders of the neck-in portion, which is unfavorable in terms of appearance. Furthermore, when the fittings are fitted, the tip of the lower body 1 hits the end of the upper body at a large contact angle, which tends to cause problems. The drawing, ironing, and neck-in processing of the lower body are known, and are performed under known conditions.
The upper body is also formed by known press working. As adhesives, heat-sealable thermoplastic resins,
For example, polyester-based, polyamide-based, acid-modified olefin resin-based adhesives are used, and these are in the form of films, powder slurries, solution sol, etc., and are preferably coated with a thermosetting resin or thermoplastic resin primer coating. Apply to the edge part to be joined through. The adhesive described above is applied to the open edges of the cups to be joined prior to mating the cups together. This adhesive layer has a resin layer thickness of 10 to 200 μm,
In particular, it is best to apply it so that the thickness is 20 to 150 μm, and the width of the overlapping joint, that is, the lap width is 1.
It is preferable to apply the coating to a thickness of 30 mm to 30 mm, particularly 2 to 20 mm. The adhesive-applied cup is fitted onto the other cup as described above, and the adhesive present in the overlap is melted and then cooled to form a seam.
Heating of the overlapping part can be done by high-frequency induction heating, infrared heating, hot air heating, heat transfer heating from a heating element, etc., and cooling of the joint can be done by any operation such as air cooling, air cooling, water cooling, etc. . The bottle according to the present invention is particularly useful as a container for contents having autogenous pressure such as carbonated drinks, beer, and low-malt beer, and as an internal pressure container for filling nitrogen gas, liquid nitrogen, etc. together with the contents. The metal bottle of the present invention has significant advantages over conventional plastic bottles (polyethylene terephthalate biaxially stretched bottles) and glass bottles. Table A summarizes these advantages.

[Table] The present invention will be explained with the following example. Example A tin-plated steel plate with a base thickness of 0.30 mm is punched to a diameter of 120 mm, and formed into a cup shape with an inner diameter of 85 mm between a drawing punch and a drawing die according to a conventional method. Next, this cup-shaped molded body was subjected to a re-drawing process, and the diameter was 66.1 mm.
It was ironed using a mm ironing punch and die. Paint the inner and outer surfaces of this lower body with epoxy paint.
After baking, we performed neck-in processing to make the outer diameter 64.14 mm. Next, a thermoplastic adhesive was applied circumferentially from the open end of the lower body to a width of 5 mm and a thickness of 50 μm using a conventional method. On the other hand, the upper body is a bright tin-plated steel plate (T-1 material plating amount #25/
50) into a disk with a diameter of 96 mm and molded by press working so that the curvature of the open end is 1/4 mm ^-1 and the tip is 1 mm larger in diameter than the vertical inner wall of the upper body (64.20 mm). and eventually added a spout for liquid. Next, the upper body and the lower body were fitted together at room temperature, and then the fitted portion was heated, the adhesive was melted, and then cooled to join the upper body and the lower body to form a bonded metal container.
A 5 mm wide circumferential joint was cut out from this container and the adhesive strength (90 degree peel strength) was measured.
The weight was almost uniform between 4.1 and 5.5 kg. In addition, the yield in fitting at this time was 100%. Comparative Example The lower body was manufactured in the same manner as in the example, and the upper body was manufactured in the same manner as in the example, except that the open end was processed so as not to extend outward beyond the vertical inner wall. An attempt was made to fit these two bodies together at room temperature, but the ends collided with each other and it was not possible to fit them together. Next, the open end of the upper body was heated to 200°C to enlarge its diameter, the two bodies were fitted together, and the fitted part was heated by high-frequency induction to melt the adhesive and then cooled to produce a joined container. The yield of fitting at this time was 35%, and the adhesive strength (90 degree peel strength) varied widely from 0.2 to 5.1 kg and 15 mm width. In addition, the shape of the open end of the upper body has a diameter expansion of 0.1
If the curvature is smaller than 1/100 mm ^-1 , the rigidity will not be very high and the effect will be small, and if the curvature is larger than 2 mm ^-1 , the upper body end and the lower body end will be damaged when mating. Because it hit at a large angle, the inner surface of the upper body was scratched and the end of the lower body was deformed. From these results, it was found that the container of the present invention not only has a uniform and strong adhesive force, but also can be easily fitted.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing separately the upper body and lower body of the metal container of the present invention, and FIG. 2 is the metal container of the present invention in which the upper body and the lower body are overlapped and joined. FIG. 3 is an explanatory diagram for explaining how to overlap and join the upper body and lower body in the present invention, and FIG. 1 is a diagram showing a preferred embodiment of the joining, in which reference numeral 1 is a lower body, 2 is an upper body, 3 and 4 are open ends, 5 is a side seam, 7 is a bottom, 8 is a side wall, 9 is a top wall, 10 is the spout, 12
indicate the thermoplastic adhesive layer, respectively.

Claims (1)

[Claims for Utility Model Registration] A lower body made of a metal cup-shaped molded body and an upper body made of a metal cup-shaped molded body are overlapped and joined together at their open ends, and In metal containers where the wall has a spout that is smaller in diameter than the side wall of the container, the open end of the lower body is narrowed by a neck-in process so that the diameter is smaller than that of the side wall. forming an inner cylindrical joint, the open end of the upper body facing an outer vertical cylindrical joint and having a diameter at least 0.2 mm larger than the inner wall of the outer joint; Spreads outward and 1/100 to 2
It has a curvature surface with a curvature of mm ^-1 , and the overlapping joint between the inner seam and the outer seam is achieved by fusion using a thermoplastic adhesive layer interposed between these two seams. A metal container characterized by: