JPS59197328A - Manufacture of metallic vessel having joint by heat bonding - Google Patents

Abstract

PURPOSE:To obtain efficiently a metallic vessel having a joint by heat bonding by heating selectively the two end edges of a vessel blank material engaged with each other via a resin layer for adhesion by using a high frequency induction heating coil disposed in a specific positional relation. CONSTITUTION:Both ends 3, 4 at a joint 5a is fitted mechanically to each other via an adhesive layer 11a and are engaged to impart an electrical insulating relation in the production of a metallic bottle, etc. The joint 5a is positioned to face roughly the center of a high frequency induction heating coil 14. The side wall 6 continuous with the inside open end 3 of the vessel is faced to the lower part 15 of the coil and the outside open end 8 is faced to the upper part 16 of the coil. The width of the joint 5a as designated as (d), the space in the transverse direction of the joint on the innermost circumference of the coil 14 as D, the space in the longitudinal direction of the joint on the innermost circumference of the coil 14 as L and the space between the coil 14 and the diametral direction of the joint 5a as (t) are determined to the relations satisfying 8d>=D>= d, 20d>=L>=d, t<D. The two ends 3, 8 of the joint are thus selectively heated and the metallic vessel formed with the joint by heat bonding is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a metal container having a seam formed by thermal bonding. The present invention relates to a method for manufacturing a metal container, which comprises efficiently and selectively heating to form a thermally bonded seam.

High-frequency induction heating is a heating means widely used for heating metal materials, and is also widely used for manufacturing metal containers having seams formed by thermal bonding such as adhesive bonding. However, the high-frequency magnetic field from the high-frequency induction heating coil is blocked by the metal material, so in conventional technology, the resin adhesive applied to the edge of the container material is melted by high-frequency induction heating before stacking. There is a method of overlapping both ends of the container material through a resin adhesive layer, and finally pumping the overlapping part while cooling to form a seam. A method has been adopted in which the outside is heated by high-frequency induction, and both ends are thermally bonded by heat transfer from the outside.

However, although the former method can be conveniently applied when thermal bonding is performed by pressing both ends in the overlapping direction, such as in lap side seam cans where the seam extends straight in the axial direction, , an upper body and a lower body each consisting of a cup-shaped molded body formed by drawing or drawing-ironing a metal material are fitted at their circumferential open ends via an adhesive to form a container. When forming
It is difficult to apply this method because the axial pressing force during fitting causes the molten adhesive layer to protrude outside the joint or cause damage to the open end.

In addition, in the latter method, the inner end of the seam is heated only by heat conduction because the high-frequency magnetic field is blocked at the outer end, and the adhesive material between the two ends is heated only by heat conduction. Because the layer has significantly poorer thermal conductivity than metal,
Heat bonding requires a significantly long time, and a temperature gradient inevitably forms in the area to be joined, with the outer edge being hotter and the inner edge being colder, making uniform heating difficult. This causes a defect. In particular, when the metal material is a ferromagnetic material such as steel, the inner end portion is difficult to heat.

Therefore, it is an object of the present invention to simultaneously and efficiently heat both edges of a container material engaged through an adhesive resin layer from the outer edge and the inner edge by high-frequency induction heating.
Moreover, the object is to provide a method that allows selective heating.

Another object of the present invention is to, when manufacturing a metal container having a seam formed by thermal bonding, apply high frequency W
=Providing a method for heating.

Another object of the present invention is to provide a method in which both ends of a material having an adhesive layer interposed therebetween can be selectively heated to a desired temperature.

Still another object of the present invention is to fit an upper body and a lower body, each of which is made of a metal seamless cup-shaped molded body, through an adhesive layer at their circumferential open ends; It is an object of the present invention to provide a method that can efficiently and selectively heat this adhesive layer from the outside of the fitting part by high-frequency induction heating.

According to the present invention, in a method for manufacturing a container that includes joining both ends of a container material containing metal through a seam formed by thermally bonding resin, the both ends are engaged through a layer of thermally adhesive resin, and A part to be a joint where both ends are locally in a substantially electrically insulating relationship and a small (one circumferential high frequency induction heating coil) with the part to be a joint located approximately in the center of the coil. , the width of the material connected to one end, the material connected to the other end, and b'' - the width of the part that faces the coil part with the opposite direction of current and is to be a seam, d.

When the distance in the width direction of the joint on the innermost circumference of the coil, the distance in the longitudinal direction of the joint on the innermost circumference of the coil, and the distance in the radial direction between the coil and the joint are t, the following formula 8 is obtained. A metal container, which is arranged in a satisfactory positional relationship, and a high-frequency induction heating coil is energized to induce a current through each of the ends to selectively heat both ends to be a seam. A manufacturing method is provided. .

As already pointed out, the present invention involves fitting an upper body and a lower body each consisting of a seamless cup-shaped molded body made of metal through an adhesive layer at their circumferential open ends, This adhesive layer is efficiently and selectively heated from the outside of the fitting part by high-frequency induction heating, and is particularly useful for producing a bottle-shaped metal container with a circumferential side seam. Therefore, the present invention will be explained below using this container as an example, but the present invention is of course not limited to this case.

In FIG. 1 showing an example of a metal bottle according to the present invention, this bottle includes a lower body 1 made of a seamless cup-shaped molded body made of a metal 61 such as a tin-plated steel plate, and a seamless cup-shaped molded body made of metal. These cup-shaped molded bodies are made up of a container by overlapping and joining the open ends 6 and 4 to form a circumferential mesh 5. integrated into the shape of

In this embodiment, the lower body 1 is a cup consisting of a tall thin side wall portion 6 formed by highly drawn and ironed metal material and a thick bottom portion 7 that has not undergone any ironing process. - The sumo wrestler body 2 is also a cup consisting of a tall thin side wall portion 8 and an upper wall 9 formed by the same molding as the lower body. The height of the side wall portion 8 of the upper body 2 is within a range that 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.

In the specific example shown in FIG. 1, the open end 6 of the lower body 1 is narrowed to a smaller diameter than the rest of the body wall by neck-in processing in the vicinity of the open end 6. It is fitted into the open end 4 of the large diameter upper body. A thermal adhesive layer 11 is provided between the outer surface of the open end 6 of the lower body and the inner surface of the open end 4 of the upper body, and the bonding between the lower body and the upper body,
Fixation is taking place. A portion of the adhesive 11 protrudes from the seam 5 and is attached to the cut edge 12 of the metal material located inside the seam.
From the viewpoint of corrosion resistance, it is desirable to form a coating layer 16 on the metal.

In the metal container having the above-described structure, only an extremely small spout 10 is formed in the upper body 2, and therefore, after the upper body 2 and the lower body 1 are fitted together, this fitting assembly is It will be appreciated that it is virtually impossible to insert a special heating mechanism ring inside the solid body, and therefore the fitting portion can only be heated from the outside.

According to the present invention, a high-frequency induction heating coil is positioned outside the fitting portion in a specific manner and energized, thereby
Not only the open end 4 located on the outside but also the open end 6 located on the inside can be heated efficiently and selectively, and bonding can be performed within a very short time.

In FIGS. 2, 6, and 4 for explaining the arrangement and principle of the high-frequency induction heating coil in the present invention, in a portion 5a that should be a seam, both ends 3 and 4 are connected with an adhesive layer 11α between them. The two end portions 3 and 4 are locally and substantially electrically insulated by the adhesive layer 11α. In this specification, the term "substantially electrically insulating locally" refers not only to cases where these are in a completely electrically insulating relationship, but also to cases where an electrical short circuit occurs in some parts, as will be explained in detail later. It also includes an electrically insulating relationship such that eddy currents across both ends 3 and 4 do not occur.

A high-frequency induction heating coil, generally designated 14, is arranged outside the portion 5α that is to become the seam in the positional relationship shown below. In the specific example shown in this drawing, the coil 14 has an overall five-wound shape. In this coil 14, as shown in FIG. 2, a current flows in the vertical direction from top to bottom at a certain point in the lower coil portion 15, and in the coil portion 16 at the same point in time. The structure is such that current flows vertically from bottom to bottom.

In the present invention, the portion 5α to be the seam is located approximately at the center of the coil 14, and the inner open end 6
The coil 14 is positioned such that the side wall portion 6 facing the lower coil portion 15 faces the lower coil portion 15, and the outer open end portion 8 faces the upper coil portion 16, respectively. In addition, as shown in Figure 2,
The width of the portion 5α to be a joint, that is, the wrap width, is d, the distance between the innermost loops of the coil 14 in the vertical width direction is D, the distance L is the distance between the innermost loops of the coil 14 in the longitudinal direction of the joint, and the coil The distance in the radial direction between 14 and the part 5α that should become a seam is t
Then, the following formula % formula % (1) (1) (2) (2) t<n ・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・(3) Especially t<3AD ・・・・・・・・・・・・・・・・・・・・・
. . . The positional relationship is such that (6α) is satisfied.

In the above-mentioned positional relationship, the high frequency induction heating coil 14
When a high frequency current is applied to the side wall portion 6 facing the coil portion 15, a current 17 is induced in the side wall portion 6 facing the coil portion 15 in a direction opposite to the current direction in the coil portion and passing in the same direction through the open end portion 6. Ru.

Similarly, in the side wall portion 8 facing the coil portion 16, a current 18 is induced to flow in the opposite direction to the current direction in the coil portion, but in the same direction as the open end portion 4. These eddy currents 17 and 18 are induced to have a low current density in the side wall portions 6 and 8 and a high current density in the open end portions 6 and 40, respectively, and as a result, the outer open end Not only the portion 4 but also the open end portion 6 located inside is heated strongly.

According to the present invention, in this case, by arranging the coil 14 and the portion 5α that should become a joint, so that the above-mentioned equations (1) to (3), particularly the above-mentioned equations (1α) to (6α), are satisfied. , it becomes possible to intensively and selectively heat both open ends 3 and 4 without heating the side wall portions 6 and 80 much.

In general, in high-frequency induction heating, the stronger the electromagnetic coupling between the coil and the metal material, the greater the amount of induced wax current.
It is believed that the heating efficiency will be higher if the area is increased. However, according to research by Namet et al. and the present inventors,
Using such a large-area high-frequency induction heating coil,
Although the heating efficiency as a whole is certainly improved, it has been found that not only the ends 6 and 4, which should form a seam, but also the side wall parts 6 and 80 that are distant from these ends are heated.

On the other hand, in the present invention, the above formula (1).

As is clear from (2) and (3), the lower coil portion 15 and upper coil portion 16 of the coil 14 are placed close to the joint portion 5α to minimize the wax current induced in the material. By making the diameter larger, it is possible to intensively and selectively heat both ends of the joint.

This fact becomes clear by referring to FIGS. 5 and 6. That is, the width of the seam (d) and the force of the tin plate are 5so
+, for the can with the shape shown in Fig. 1 with the outer diameter of the seam being 64 tan, in the case of Fig. 5, the high frequency induction heating coil with D = 15 stitches, L = -151, t-61, in the case of Fig. 6 is D=15
This shows the temperature distribution downward from the inner edge of the seam when heating is performed for 0.3 seconds with a constant high frequency input power using a high frequency induction heating coil of m, L = 110w, t = 3m. . From this result, when induction heating is performed in an arrangement outside the scope of the present invention (Fig. 6), in addition to the edges where the seams should be formed, the side walls are also heated over a fairly wide area to a higher temperature than the edges. While it takes a relatively long time to heat the end portion to a predetermined temperature (approximately 220°C), when induction heating is performed in an arrangement within the scope of the present invention, the temperature rise in the side wall portion can be reduced to a relatively low level. It is understood that rapid heating can be performed locally, intensively and selectively, while suppressing the heating. The above-mentioned tendency is observed not only in the lower part but also in the upper part, that is, the part located above the outer edge of the seam.

Furthermore, even in the case of a heating coil in which the spacing in the seam width direction of the innermost circumference of the coil is outside the range of the present invention, the side wall portion that is electromagnetically coupled to the coil portion is heated significantly, and the portion that should be the seam is heated. There is a tendency that it is difficult to moreover,
The larger the distance t in the radial direction between the coil and the seam, the weaker the electromagnetic coupling between the heating coil and the seam, and the lower the efficiency tends to be. In this case, it is recognized that the joint area will not be heated unless excessive high-frequency input power is applied.

Furthermore, the closer the distance between the innermost circumferences of the coils and L to the width of the part to be a seam, the more the effect of intensively and selectively rapidly heating the end part to be a seam becomes more effective. It is recognized that this is particularly noticeable when the material of the lower body is ferromagnetic (for example, steel) than when it is nonmagnetic (for example, aluminum).

In the present invention, the reason why intensive and selective heating of the ends is made possible by adopting the above-described arrangement has not yet been elucidated. However, the present inventors estimate the reason for this as follows. In other words, the higher the current density of the melting current induced at the overlapping ends to become a seam, the more intensive and selective heating of the ends becomes possible. When arranging the coil, place it close to the part where the seam is to be formed. [Since the innermost loop of the coil is provided, the ratio of the induced eddy current passing through the ends is increased, which increases the current density at the ends.] is possible, and the thin current induced by the coil includes an eddy current that is induced along the coil and returns through the rear end, and a portion opposite the end that is induced along the coil. However, in the present invention, by setting the values of D and L to the small ranges mentioned above, the curvature of the coil becomes thicker, so that the latter per eddy current of the former becomes thicker. This is thought to be due to a decrease in the ratio of eddy current.

This effect is more pronounced when the upper and lower bodies are made of ferromagnetic material than when they are non-magnetic, and the reason is that when the inductance of the current path through the ends is ferromagnetic, This is thought to be due to the fact that the current passing through the end portions is small as the size increases.

In the present invention, the dimensions and arrangement of the coil can be defined only by the dimension of the innermost circumference of the coil and L for the following reason. In other words, the eddy current in the material is induced by the current in the coil, but the smaller the curvature of the coil, the smaller the curvature of the eddy current, and the smaller the electrical resistance, so the larger the current. You will be guided.

Thus, even if the coil 14 is a coil that has been wound many times, such as a spiral wound coil, the innermost one acts most effectively on induction heating, and from this point of view, in the present invention, This defines the dimensions of the innermost coil.

If the above-mentioned values of D and L exceed the range of the present invention, as explained with reference to FIG. If the temperature is smaller than , it becomes difficult to achieve the objective of the present invention, which is to heat the inner end portion to a predetermined temperature as well.

The distance t between the coil 14 and the end portion 5α is related to electromagnetic coupling between the coil and the material, and if the value of t exceeds the above range, efficient heating becomes difficult.

In the present invention, the heating coils 14 include the second to fourth heating coils.
The five-turn type shown in the figure may be one-turn. In addition, as shown in FIG. 2, in order to strengthen the electromagnetic coupling between the coil 14 and the material, a magnetic material core 19 such as ferrite is used.
You can also use

By using the spiral-wound coils shown in Figures 2 to 4, it is possible to vary the common imaging frequency over a wide range by changing the number of turns, and by increasing the inductance, the capacity of the capacitor used can be relatively reduced. 17- Can be made small.

The present invention also has the advantage of workability in that by using the coils having the dimensions and arrangement described above, high frequency induction heating operations can be performed stably without any trouble. In the above-mentioned manufacturing method of a container consisting of an upper body and a lower body and having a circumferential seam, even if an electrically insulating adhesive resin is interposed between the two ends, for example, the cut edge of the upper body is not connected to the lower body. There may be cases where the side walls are in contact at some points, creating an electrical short circuit. In this case, if an eddy current is induced through the upper body and the lower body through the two short-circuit positions, spark discharge will occur at the short-circuit position, causing burnt paint, etc., resulting in poor appearance, and further This has the disadvantage that the temperature near the spark discharge location decreases. According to the present invention, the above-described configuration limits the generation area of eddy current to a relatively narrow area, so the probability of generation of eddy current passing through two short-circuit positions is suppressed to a significantly small value, and stable induction heating is achieved. Operation becomes possible.

In the present invention, since the heating coil 14 has a relatively small dimension in the circumferential direction, a large number of heating coils 14 can be arranged in the circumferential direction of the seam to perform heating in an even shorter period of time. For example, a method in which a large number of high-frequency induction heating coils are arranged so as to substantially cover the periphery of a circumferential fitting part, and induction heating is performed while the upper and lower fitting parts are stationary; A method of arranging a high-frequency induction heating coil and inductively heating the fitted object of the upper and lower bodies while rotating is appropriately used.

Any high frequency current used in this type of induction heating can be used as the high frequency current to be applied to the coil, and for example, generally speaking, a high frequency of 10 KB'Z to 5 Q Q KHz is preferably used. Although the input to the heating coil varies depending on the size of the container, the required temperature and heating time, and cannot be generally specified, according to the present invention, by adopting the above conditions, the input power can be reduced compared to other cases. It will be clear from the description of FIG. 6 above that heating can be achieved in a fairly short time.

According to the present invention, the outer end and the inner end can be heated to the same temperature, or they can be heated to different temperatures.

In the present invention, any material that exhibits adhesive properties by being melted, softened, or activated by heat may be used as the adhesive layer, such as thermoplastic resin adhesives such as polyester, polyamide, and acid-modified polyolefin. Agents are advantageously used, but are of course not limited thereto.

Container materials used include light metals such as aluminum, tinplate, nine-free steel, various other surface-treated steel plates, black plates, and other metal-containing materials, and these materials are coated with various paints. It doesn't matter what it is.

Further, this material may be a laminate of gold paulownia foil and a plastic film, and if this plastic film exhibits heat-sealing properties, it is natural that it can be used as the adhesive layer.

The present invention is suitably applied to manufacturing a container having the above-mentioned circumferential seam. For example, as shown in FIG. 22
．． 6 can be advantageously used for lock-seam joining via the adhesive layer 11, and can also be advantageously used for heat-sealing the periphery of the lid and the flange of the body using a thermal adhesive.

The invention is illustrated by the following example.

EXAMPLE Material A tin-plated steel plate with a thickness of 0.30 m was punched into a disc with a diameter of 120 mm, and formed into a cup shape with an inner diameter of 8511211 mm between a drawing punch and a drawing die according to a conventional method.

Next, after subjecting this cup-shaped molded product to a re-drawing process,
Ironing was performed using an ironing punch with a diameter of 66.10 mm and an ironing die.

Next, after degreasing and cleaning the inner and outer surfaces of this lower body, a conventional surface treatment (phosphoric acid) was performed, and the inner and outer surfaces were painted and baked with epoxy paint, followed by neck-in processing (
Neck-in part outer diameter: 65.55mm). Then thickness 6
0μm, width 6m polyester adhesive tape (softening point 1
78°C) to the outer open end of the lower body using high-frequency induction heating so that the bait protrudes by 1.0 mm from the open end, and then the protruding part of the tape is attached to the edge of the open end and the inner surface following this. 21- was bent inward to enclose it, and the adhesive tape was heat-sealed to the inner and outer surfaces of the open end.

On the other hand, for the upper body, a 0.23 m thick tin-plated steel plate with epoxy paint applied on both sides was punched out into a 96-diameter circular plate, which was then formed by conventional press processing, with a spout attached to the upper wall. Established. (Upper body diameter 63.37, >Next, the lower body to which the adhesive tape was applied and the upper body were fitted so that the overlapping portion was 5M with their open ends, and then the heating coil shown below was fitted. A high-frequency heating process and a cooling process in the same stillage were performed to melt the adhesive at the fitting part, cool and solidify it, and perform the bonding process to produce a bonded metal container.The heating coil in this example, the heating process, The cooling process will be explained in detail.

The shape of the heating coil is a wax-wound coil as shown in Figures 2 to 4, and the diameter of the conductor used in the coil is 4 m.
φ, and the number of turns of the heating coil electromagnetically coupled to the upper body and the lower body is 6 turns.

The innermost circumferences D and L of the coil are 15 m.

In the heating process, the heating coil is arranged so that the distance between the heating coil and the seam in the radial direction is 6 mm, and the center of the heating coil is two circles above the center of the seam. While rotating it so that it rotates 10 times within the heating time,
When heated for 0.6 seconds using a 153 K11z high frequency oscillator with an input of 4 fF, the temperatures at both the outer and inner ends were 220°C. At the same time as heating is completed, a compressed air nozzle (source pressure 5 kg/cm) is used in the cooling process.
), and in 15 seconds the temperature of the fitted portion reached 140° C. or higher, the temperature at which the adhesive solidifies.

Comparative Example An upper body and a lower body were manufactured in the same manner as in the example, and after fitting the upper body and the lower body in the same manner as in the example, the heating coil was placed outside the range of the present invention (D = 15 holes, L = 110■), and when the fitting part is heated with high frequency, the temperature of the fitting part is 220
℃, a high frequency input power of 5.5ff is required, and the temperature of the side wall is higher than that of the fitting part.
After the heating was completed, we tried to cool the joint using a compressed air nozzle, but the temperature of the mating part fell below the temperature at which the adhesive solidified.
It took more than 5 seconds.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an example of a metal bottle of the present invention, FIGS. 2 to 4 are views showing the arrangement of high frequency induction heating coils in the present invention, and FIGS. 5 and 6 are: A diagram showing the relationship between axial distance and heating temperature, FIG. 7 is a diagram showing an example of application of the present invention. 1 is a lower body, 2 is an upper body, 6 and 4 are open ends, 5 is a circumferential side joint, 6 is a thin side wall, 7 is a thick inner bottom, 8 is a thin side wall, 9 is an earthen wall, 10 is a spout, 11 is an adhesive layer,
12 is a cutting edge of a metal material, 16 is a coating layer, 14 is a high frequency induction heating coil, 15 is a lower coil portion, 16 is an upper coil portion, 17 and 18 are eddy currents, and 22 is a metal material. Patent Applicant: Showa Kishimoto Figure 1 Figure 2 Figure 3 Figure 4 Figure 7 Procedural amendments (voluntary) June 17, 1981 Commissioner of the Patent Office Kazuo Wakasugi 1, Patent Application for Indication of Cases Showa No. 58-71517 No. 2, Title of the invention: Process for manufacturing a metal container with a seam made by thermal bonding 3, Relationship with the case of the person making the amendment Patent applicant: 4, Attorney: 105-5, No date of amendment order 6: Amendment Column 7 of Detailed Description of the Invention in the Subject Specification, Contents of Amendment (1) In the 6th line from the bottom of page 11 of the specification, "Part 4" is corrected to "Part 4." (2) On page 19, line 5, the phrase “the following” should be corrected to read “of the upper and lower body.” (3) In the 4th line from the bottom of page 22, the words "upper body and lower body" are corrected to read "upper body and lower body J." (4) In the 9th line of page 23, the word "r15 seconds J" is corrected. , “1.
Correct A for 5 seconds. that's all

Claims (1)

[Claims] (1) In a container manufacturing method that involves joining both ends of a container material containing metal through a seam formed by thermally bonding resin, both ends are engaged through a layer of thermally adhesive resin and locally At least one circumferential high-frequency induction heating coil is connected to a portion to be a joint whose ends are substantially in an electrically insulating relationship, and the portion to be a joint is located approximately in the center of the coil,
The width of the part where the material connected to one end and the material connected to the other end face the coil part where the direction of current is opposite and should be a joint is d, and the direction in the middle of the joint at the innermost circumference of the coil. The interval is . When the distance in the longitudinal direction of the seam on the innermost circumference of the coil is ゛L, and the distance in the radial direction between the coil and the seam is t, arrange it in a positional relationship that satisfies the following formula % formula %. A method for manufacturing a metal container, characterized in that the two ends to be joined are selectively heated by inducing a current to pass through each of the ends.