JPH027731B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a metal container having a peripheral joint, and more specifically to a metal container having a peripheral joint joined via an adhesive layer. Relating to a manufacturing method.

(Prior Art) As shown in FIG. 1, an open end of a relatively thin lower can body 3 having a bottom portion 3a is placed within an open end portion 2b of a relatively thin upper can body 2 having a mouth portion 2a. The part 3b (which has been reduced in diameter to become a reduced diameter part) is fitted through the adhesive layer 4 made of heat-fusible plastic, and the fitted part is heated to a temperature at which the plastic can be heat-fusible. When sealing the metal cap 6 with a winding tool (not shown) around the opening 2a of the metal container 1 on which the circumferential joint 5 is formed, the height of the metal container 1 is uneven. If so, it is likely to result in a poorly sealed container (if the height is smaller than the specified value) or a container whose body portion 1a has buckled and lost its commercial value (if the height is higher than the specified value). A mounting plate for the metal container 1 (not shown) and a claw part of the seaming tool (not shown)
This is because the distance between them is constant regardless of variations in the height of the metal container 1.

However, in the process of manufacturing the metal container 1,
During the transfer from the mating device to the mating part heating device,
Phenomena such as slipping in the axial direction at the mating part or tilting of the upper can body 2 with respect to the lower can body 3 are likely to occur, and even if they are aligned at the same height during mating, it will simply be impossible to mate. There was a problem in that it was difficult to manufacture metal containers 1 of uniform height by simply heating the parts.

However, the metal container 1 with a circumferential joint 5
This seems to be because it is relatively new, but no means to solve this problem has been proposed in the past.

Further, when the open end portions 2a and 3b are relatively thin (for example, about 0.15 to 0.3 mm), the fitting portion is often not a perfect circle. Therefore, when the mating part is heated by a high-frequency induction heating coil (hereinafter referred to as a heating coil), there will be a difference in the distance between the heating coil and the heating coil along the circumferential direction of the mating part. It is not heated uniformly, which tends to result in incompletely fused parts without airtightness, or burnt parts due to overheating.

(Problems to be Solved by the Invention) An object of the present invention is to provide a method for manufacturing a metal container having a circumferential joint portion having a defined and constant height.

(Means for Solving the Problems) The method of manufacturing a metal container having a circumferential joint and having a specified height H according to the present invention comprises a lower hollow body having a bottom and an upper hollow body having a mouth and a shoulder. After each open end is fitted via a heat-fusible adhesive layer to form a fitted container assembly having a fitting part, the adhesive layer is removed by heating the fitting part. A method for manufacturing a metal container having a local joint by heating and melting, the bottom portion of the container assembly having a height slightly lower than a specified height H being placed on a second member;
The plug of a first member having a plug that can be loosely inserted into the mouth is inserted into the mouth, and the bottom of the lower surface of the first member facing the upper surface of the mouth is connected. The first member is attached to the second member such that the height relative to the upper surface portion of the second member that contacts the ground is equal to the specified height H.
After being fixed facing the member of the plug, pressurized gas is introduced into the container assembly from the opening through the conduit hole penetrating the stopper to increase the internal pressure of the container assembly. At the same time, the fitting portion is heated to melt the adhesive layer; The increased internal pressure causes the open end of the upper hollow body to axially move through the melted adhesive layer to the opening of the lower hollow body. The molten adhesive layer is slid along the end portion until the upper surface of the mouth portion and the lower surface portion of the first member come into contact with each other; in the state of contact, the molten adhesive layer is cooled and solidified.

(Function) The method of manufacturing a metal container having a circumferential joint and having a specified height H according to the present invention includes a lower hollow body 3 and an upper hollow body 2.
A container assembly whose height is slightly lower than the specified height H, which is formed by fitting each opening end of the The ground plane 3 at the bottom of the lower surface portion 16b ₁ of the first member (sealing device 16) placed on and facing the upper surface 2a ₁ ′ of the mouth portion
After fixing the _first member facing the second member so that the height relative to the upper surface 13a ₁ portion of the second member in contact with a 1 is equal to the specified height H, the upper surface 2
Since the open end 2b of the upper hollow body is slid in the axial direction until _a1 ' and the lower surface part _16b1 come into contact, the height of the container assembly becomes the specified height H in the state of contact. .

The first member is a plug part 16a that can be loosely inserted into the mouth part 2a.
The plug part is inserted into the mouth part when the first member is fixed facing the second member. Then, in order to perform the above-mentioned axial sliding, pressurized gas is introduced into the container assembly from the mouth portion 2a through the guide hole 16c penetrating the stopper portion to increase the internal pressure of the container assembly, At the same time, the fitting portion 7 is heated to melt the adhesive layer 4.

The stopper is loosely inserted into the mouth, so there is no space between the two.
The gap is extremely small, so there is little impediment to the increase in internal pressure. This internal pressure causes a lifting force to act on the shoulder portion 2c of the upper hollow body 2.

Since the coefficient of friction between the open ends 2b and 3b is reduced due to the molten adhesive layer, the sliding in the axial direction easily progresses due to this upward force. Since the plug part is loosely inserted into the mouth part, this sliding is not hindered until the aforesaid contact is made.

Since the adhesive layer is cooled and solidified in the abutting state, the container assembly after being cooled and solidified,
That is, the height of the metal container of the present invention is the prescribed height H described above.

(Example) In FIG. 2, reference numeral 11 denotes an adhesive layer 4 attached to a reduced diameter open end 3b (hereinafter referred to as reduced diameter portion) of the lower can 3 within the open end 2b of the upper can 2. This is a metal container assembly formed by intervening to form a fitting part 7.

The upper can body 2 in this example is a relatively thin (e.g., about 0.15 to 0.30 mm) metal blank (e.g., made of a tin-plated steel plate or an aluminum alloy plate with at least both sides painted).
A cup-shaped body is formed by drawing, a mouth part 2a is formed by burring the bottom part, and a bead part _2a1 for fixing the metal cap 6 is formed at the end of the mouth part 2a. It is made by twisting.

On the other hand, the lower can body 3 is made by drawing a metal blank of the same type as that used for the upper can body 2 to form a cup-shaped body having the same outer diameter as the upper can body 2, and then shrinking the open end. Diameter processing is performed to form a reduced diameter portion 3b,
It is made by forming an adhesive layer 4 made of heat-fusible plastic along the outer peripheral surface of the reduced diameter portion 3b. In the case of Fig. 2, the end face of the reduced diameter part 3b (it is a cut edge and the metal is exposed)
For protection, the adhesive layer 4 also covers the end surface and the upper inner peripheral surface of the reduced diameter portion 3b.

As the heat-fusible plastic, a thermoplastic plastic having a relatively low melting point and a polar group, such as modified linear polyester, nylon 12 or nylon 11, or acid-modified polyolefin, is preferably used. The adhesive layer 4 may be formed by powder coating or slurry coating (drying and solidifying after coating), but it is preferable to form the adhesive layer 4 by heat-sealing the plastic tape to the reduced diameter part 3b. This is the most preferred method since it provides an adhesive layer free of defects such as pores.

The fitting is achieved by a tight fit using a suitable fitting device, such as a fitting die. The metal container assembly 11 formed as described above is transported to the heating device 12 and the fitting portion 7 is heated so that the adhesive layer 4 is attached to the open end portion of the upper can body 2.
A circumferential joint portion 5 (see FIG. 1) is formed by heat-sealing on the inner circumferential surface of b.

The heating device 12 includes a mounting plate 13 for the metal container assembly 11, a high-frequency induction heating coil 14 (hereinafter referred to as a heating coil), and a magnetic core 15 made of ferrite surrounding the heating coil 14. The mounting plate 13 has a mounting portion 13 having an inner diameter substantially equal to the outer diameter of the vicinity of the bottom 3a of the lower can body 3.
a, the metal container assembly 11 is inserted into the mounting part 13a, and the ground surface 3a ₁ of the lower can body 3 contacts the upper surface 13a ₁ of the mounting part 13a.

An annular heating coil 14 consisting of multiple turns,
The magnetic core 15 surrounds the metal container assembly 11 and is coaxial with the lower can body 3 at a position where the magnetic flux is best concentrated on the fitting part 7 of the metal container assembly 11 inserted into the mounting part 13a. It is supported and disposed by a support (not shown).

16 is by supplying pressurized gas (usually air),
It is a sealing device for increasing the internal pressure and thereby obtaining the metal container 1 of a specified height, and includes a plug part 16a that can be loosely inserted into the mouth part 2a of the upper can body, and the plug part 1.
6a and has a bottom surface 16b ₁ having a shape corresponding to the upper surface 2a ₁ ' of the bead portion 2a ₁ , and has a circumferential groove 16b into which the bead portion 2a ₁ can be loosely inserted. At least the circumferential surface of the circumferential groove 16a is
In order to allow the a ₁ to slide easily, it is preferable that it be made of a material with a low coefficient of friction, such as fluororesin or MC nylon.

The plug part 16a has a guide hole 16c for supplying pressurized gas.
The guide hole 16c passes through the shaft 17 and communicates with a pressurized gas source (not shown).
The sealing tool 16 is moved so that the peripheral groove 16b is connected to the mounting portion 13a by a drive device (not shown) via the shaft 17.
It is moved up and down to maintain coaxiality with the

A plurality of locking shafts 18 are fixed to the mounting plate 13, and the sealing member 16 is lowered to lock its flange portion 16d on the upper surface 18a of the locking shaft 18.
In the above locked state, the height of the locking shaft 18 is between the top surface _13a1 of the mounting portion 13a and the bottom surface 16 of the circumferential groove 16b.
The distance d between b _{and 1} is determined to be equal to the specified height H of the metal container 1 to be manufactured. Normally, the height h of the metal container assembly 11 when inserted into the mounting portion 13a is slightly smaller (for example, about 0 to 1 mm smaller) than the specified height H, as shown in FIG. As _shown in _{FIG .}
exists.

Place the metal container assembly 11 on the placement part 13a,
The sealing tool 16 is lowered and is locked to the locking shaft 18 in the pressed state. At that time, the plug part 16a is inserted into the opening part 2a, and the bead part 2a ₁
is inserted into the circumferential groove 16b, and if the upper can body 2 is inclined with respect to the lower can body 3, the inclination is corrected and the coaxiality of both is ensured.

In the state shown in FIG. 2 as described above, the heating coil 14 is energized and at the same time pressurized gas is introduced through the guide hole 16c. Then, the fitting part 7 and the metal in its vicinity are heated by induction, and the adhesive layer 4 reaches its heat-sealable temperature (i.e., a temperature higher than the melting point or softening point of the thermoplastic, usually about 200°C or higher).
It is heated to melt and soften.

Due to the rise in temperature of the pressurized gas and internal air (due to heat transfer from the heated fitting part 7 and its vicinity), the metal container assembly 11
The internal pressure also increases. Therefore, the internal gas tries to escape from the gap between the mouth part 2a and the side surface of the stopper part 16a, but since the gap between them is extremely small, the amount of escape is limited, and therefore the internal pressure rarely decreases. It's not easy.

Due to the upward force applied to the shoulder 2c of the upper can body 2 due to this internal pressure, the open end 2b of the upper can body 2
and the adhesive layer 4 in which the mouth portion 2a is melted and softened, respectively.
The upper can body 2 slides along the reduced diameter part 3b of _the lower can body and along the side surface _of the stopper part 16a through
b ₁ rises until it makes contact (see Figure 3). The result is a top surface 2a ₁ ' and a bottom surface 16 with corresponding shapes.
The metal container assembly 11 is substantially sealed since the b ₁ contacts under pressure due to the internal air pressure and the pressure applied to the closure 16.

At the same time, due to the internal gas pressure, a radially outward force acts on the fitting part 7, so that the fitting part 7 becomes a perfect circle and is heated substantially uniformly by the heating coil 14 along its entire circumference. is heated to. Therefore, it is possible to form a sound circumferential joint 5 free from defects such as incompletely fused parts without airtightness and burnt parts due to overheating.

In order to ensure the perfect circle of the fitting part 7, the air pressure and amount should be adjusted so that the internal gas pressure (gauge pressure) is approximately 0.3 kg/
It is desirable to control it so that it is at least ^cm2 . about
This is because if it is smaller than 0.3 Kg/cm ² , it will be difficult to ensure a perfect circle. Pressurized gas will not escape through the molten adhesive layer even if the internal pressure is considerably increased, but in this case, the force acting on the sealing device 16 and the mounting plate 13 will be large, so it is necessary to support both and the mounting plate 13. It is necessary to make the mechanism for Normally, an internal pressure of about 1.0 Kg/cm ² can produce sufficient effects.

Note that the above-mentioned rise in the upper can body 2 occurs even when the internal gas pressure is approximately 0.1 kg/cm ² , so if only the height of the metal container 1 is specified, the internal gas pressure should be approximately 0.1 kg/cm ² . good.

Next, while maintaining the above internal gas pressure, the heating coil 14 is deenergized (the energization time is usually about 0.3
~2.0 seconds), the heat near the fitting part 7 rapidly escapes to other parts of the upper can body 2 and lower can body 3 by heat conduction, and the adhesive layer 4 cools to the solidifying temperature, and the peripheral joint part 5 is formed. During this time, the top surface 2a ₁ ' and the bottom surface 1
6b ₁ contact continues. Therefore, a metal container 1 having a circumferential joint 5 and having a specified height H as shown in FIG. 3 is obtained. Next, the supply of pressurized gas is stopped, the sealing device 16 is raised, and the metal container 1 is taken out from the mounting plate 13 and sent to the next process.

The present invention is not limited to the above-described embodiments. For example, the heating coil does not surround the entire circumference of the fitting part, but instead has an arc-shaped heating coil (however, a virtual circle formed with the arc as a part of the heating coil) (the center point of which is located on the axis of the lower can body 3) may be brought into contact with a part of the circumferential surface, and the metal container assembly 11 may be heated while being rotated. The upper can body and the lower can body may also have any other shape, and may also have a side seam such as a weld.

(Effects of the Invention) According to the present invention, it is possible to manufacture a metal container having a circumferential joint portion having a prescribed line height.

Furthermore, the present invention makes it easy to uniformly heat the fitting part of the container assembly in the circumferential direction, so that the fitting part of the container assembly can be heated uniformly in the circumferential direction. This method has the advantage that a metal container having surface joints can be easily manufactured.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing a metal container to which the present invention is applied, sealed with a metal cap, and FIGS. 2 and 3 are illustrations for explaining an embodiment of the method of the present invention. FIG. 2 is a longitudinal sectional view showing the state before the fitting portion is heated, and FIG. 3 is a drawing showing the state after the fitting portion is heated. DESCRIPTION OF SYMBOLS 1...Metal container, 2...Upper can body (upper hollow body), 2a...Mouth, 2a ₁ '...Top surface, 2b...Open end, 2c...Shoulder, 3...Lower can body (lower hollow body), 3a... bottom, 3a ₁ ... ground plane, 3b...
...Reduced diameter part (opening end), 4...Adhesive layer, 5...
Local joint part, 7... Fitting part, 11... Metal container assembly, 13... Placing plate (second member), 13a ₁ ...
...Top surface, 16...Sealing tool (first member), 16b ₁
... lower surface part (bottom surface of circumferential groove), 16c ... guiding hole.

Claims (1)

[Claims] 1 The opening ends of a lower hollow body having a bottom portion and an upper hollow body having a mouth portion and a shoulder portion are fitted through a heat-fusible adhesive layer to form a fitted container assembly having a fitting portion. A method for manufacturing a metal container of a specified height H having a circumferential joint part by heating the fitting part to melt the adhesive layer after forming a three-dimensional part, the method comprising: The bottom of the container assembly, which is slightly lower than the specified height H, is placed on the second member; so that the height of the lower surface portion of the first member inserted into the mouth portion and facing the upper surface of the mouth portion relative to the upper surface portion of the second member that contacts the ground plane of the bottom portion is equal to the specified height H. After fixing the first member facing the second member; pressurized gas is introduced into the container assembly from the opening through the hole penetrating the stopper; increasing the internal pressure of the assembly; simultaneously heating the mating portion and melting the adhesive layer; the increased internal pressure causes the open end of the upper hollow body to move along the axis through the molten adhesive layer; direction along the open end of the lower hollow body until the upper surface of the opening and the lower surface portion of the first member abut; in the abutting state, the molten adhesive layer is cooled and solidified. A method for manufacturing a metal container of a specified height having a circumferential joint, characterized in that: