JPH0139921B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for manufacturing a container with a lid thermally bonded, and more specifically to a container in which a lid is reliably thermally bonded to an open end by high-frequency induction heating at a high production rate. The present invention relates to a manufacturing method and apparatus.

Conventionally, as a container for storing hygroscopic foods such as seaweed, for example, as shown in FIG. A container 4 is used, which is thermally bonded with a lid part 3 having a high elasticity as an inner lid. After the container 4 is filled with the contents through the opening 5 at the bottom, the bottom plate (not shown) and the flange 6 are sealed by double seaming, and the outer lid 8 is inserted into the neck-in part 7 as a product. be converted into When in use, after removing the outer lid 8, the contents are taken out by peeling off the lid (inner lid) 3 or tearing it with a knife or the like. Alternatively, although not shown in the drawings, after filling a container body such as a metal can, plastic container, or wide-mouth glass bottle with the contents from the beginning, the open end (flange, curl, or body wall) may be If the wall is thick, a similar lid (in this case, it is not necessarily the inner lid)
Containers made by thermally bonding are also widely used.

As a heating means for this thermal bonding, when the opening end and/or the lid includes a metal layer, high-frequency induction heating is superior in terms of its high heating speed. The main method used is to heat the opening end or the lid with several high-frequency induction heating coils, then place the lid on the opening end, press it, and thermally bond it, so the time required for things other than heating is time-consuming. For a long time, it has been difficult to obtain high production rates (i.e., the number of pieces produced per minute per device).

The present invention aims to solve the problems of the prior art as described above, and to achieve the above object, the present invention provides a container in which a lid is thermally bonded to the open end of the container body. In the method of manufacturing,
The open end and/or the lid have a surface made of a heat adhesive layer, and at least one of the open end and the lid has a metal layer, and the method includes: a step of punching out and adhering it to a high frequency induction heating coil device including a heating coil having a shape corresponding to the opening end, a step of moving the high frequency induction heating coil device, a lid adsorbed to the high frequency induction heating coil device. a step of pressing the heating coil and the opening end, a step of applying electricity to the heating coil to perform thermal bonding, a step of deenergizing the heating coil after the thermal bonding is completed,
Provided is a method for manufacturing a container with a lid portion thermally bonded, the method comprising the step of releasing the pressure after the temperature of the thermal bonding portion has decreased to a temperature lower than the melting point or softening point of the thermal adhesive layer. It is.

Further, the present invention provides an apparatus for thermally bonding a lid to an open end of a container body, the apparatus comprising a plurality of pockets for storing and transporting the container body, and a turret that rotates intermittently; a high-frequency induction heating coil device including a heating coil having a shape corresponding to the open end portion and having a vacuum suction hole; provided opposite to the high-frequency induction heating coil device at a fixed position where the pocket portion stops; A device for punching out the lid from the web; a device for bringing the punched lid close to the high-frequency induction heating coil device and adsorbing it; a container body housed in the pocket downstream of the punching device; A device for pressing the opening end and the lid; a rotary transformer for supplying current from a high frequency oscillation device to the heating coil; and a device for supplying current from the rotary transformer to the heating coil; A switch device that deenergizes the heating coil after the end portion and the lid are thermally bonded; or a fixed primary coil connected to a high frequency oscillator, and a plurality of fixed primary coils that can revolve while facing the primary coil in close proximity. a secondary coil, and the secondary coil is connected to a corresponding heating coil such that at an upstream end of the primary coil the heating coil is energized and at a downstream end the heating coil is deenergized. The present invention provides an apparatus for thermally bonding a lid to an open end of a container body, characterized by comprising a rotary transformer configured to: and a device for releasing the pressure after the deenergization.

The present invention will be described below with reference to the drawings which are examples.

In FIGS. 2 and 3, the lid thermal bonding device A includes a turret 9 and a web cutter 10. As shown in FIG. The turret 9 includes a central shaft 11, an upper rotary disk 12 and a lower rotary disk 13 fixed to the central shaft 11, and the upper rotary disk 12 further includes a guide plate 14 and a top plate 15. The guide plate 14 is provided with a plurality of (eight in the figure) semicircular recesses 14a at equal intervals in the circumferential direction, and guide holes 13a are provided at positions corresponding to the recesses 14a of the lower rotary disk 13. The support plate 1 of the container body 1 is placed inside the guide hole 13a.
6 are provided to be vertically slidable, and these form a pocket portion 17 for storing and transporting the container body 1. A cam roller 18 is provided at the lower end of the shaft 16a of the support plate 16, and as the cam roller 18 rolls along a cam groove 19a of a ring-shaped cam 19 provided below the lower rotary disk 13, , the support plate 16 moves up and down. The turret 9 rotates intermittently in the direction of arrow
is loaded into the pocket portion 17 at the loading station P by a loading mechanism (not shown). A groove 16b is formed in the support plate 16 so that the container body 1 can be accurately positioned directly below a high-frequency induction heating coil device 22, which will be described later. The container 4 (FIG. 1) to which the lid 3 is thermally bonded is delivered from the pocket 17 at the delivery station Q by a delivery mechanism (not shown). The pocket parts 17 located at the charging station P and the delivery station Q are connected to the web 20 for the lid part 3 and the web scrap 20' (web cutter 10), respectively.
21 is the remaining part punched out of the lid part 3;
(Although only one hole is shown in the figure, in reality, many holes are formed almost continuously), the container body 1 passes through it when it is loaded and delivered.
Container body 1 is web 20 or web scrap 2
The height of the cam grooves 19a near the loading and unloading stations P and Q is set at a low level so that the support plate 16 can be lowered to a position where it can pass below the loading and unloading stations P and Q.

On the other hand, from when the container body 1 leaves the charging station P until it approaches the delivery station Q,
The open end 2 of the container body 1 is pressed against the high-frequency induction heating coil device 22 fixedly installed on each recess 14a through the lid 3 (to the extent that an appropriate pressing force is secured for thermal bonding). As such, the height of the cam groove 19a at the corresponding position is set to a high level.

The high frequency induction heating coil device 22 has an open end 3
High frequency induction heating coil 2 having a shape corresponding to
3 (referred to as a heating coil in this specification), an annular cooling mantle 2 for cooling the heating coil 23;
4. A magnetic core 25 made of a high magnetic permeability material (for example, ferrite), a thin heat-resistant elastic sheet 26 (for example, made of silicone rubber), and a fixing member 27 (non-magnetic, electrically insulating, relatively heat-resistant and mechanically The fixing member 27 is made of a material with excellent strength, such as cloth impregnated with phenolic resin, and is fixed to the lower surface of the top plate 15. As shown in FIG. 4, the heating coil 23 has many turns (6 turns in the figure).
Since it is made of a thin copper ribbon (with a heat-resistant insulating film (not shown) formed on the surface) (actually 10 turns or more is preferable), the heating efficiency is high and the required current is very small compared to a single turn heating coil. It has the advantage that it can be heated to a thermal bonding temperature at 100 Hz, and therefore semiconductor switching elements (such as SCRs or transistors) as described below can be used for switching the current. It also has the advantage of not requiring a current transformer. The cooling sleeve 24 has a guide plate 14 that passes through the center shaft 11.
Cooling water circulates in the direction of the arrow through a conduit 28 extending above. The magnetic core 25 is provided with a vacuum suction hole 29 for adhering the lid portion 3 punched from the web 20 to the lower surface of the high-frequency induction heating coil device 22 . The vacuum suction hole 29 communicates with a vacuum device (not shown) via an electromagnetic on-off valve 30 and a guide hole 31 in the central shaft 11 . The electromagnetic on-off valve 29 opens immediately after the pocket portion 17 corresponding to the electromagnetic on-off valve 29 is located at the delivery station Q and sends out the container 4, and communicates with a vacuum device (not shown). When a new container main body 1 is inserted, the lid 3 on the open end 2 is pressed against the high-frequency induction heating coil device 22 and then closed, and at the same time, the vacuum suction hole 29 and the outside air are communicated. controlled by a switching device (e.g. a limit switch). The reason why the elastic sheet 26 is attached to the lower part of the heating coil 23 is to apply almost uniform pressure to the lid part 3 even if the opening end part 2 has some irregularities, thereby maintaining the airtightness of the heat-bonded part. This is to ensure that

Power is supplied to the heating coil 23 via a rotary transformer 32, a switch device 33, and a feeder 34 from a high frequency oscillator (not shown).
The rotary transformer 32 has fixed parts 35 and 2 on the primary side.
The next side consists of a rotating part 36 (fixed to the center of the top plate 15), and magnetic cores 35a and 36a (made of ferrite, for example) each having an E-shaped cross section,
and windings 35b and 36b in the recess of the magnetic core.
Therefore, the gap between the magnetic cores 35a and 36a is narrowly determined to increase the degree of electromagnetic coupling. Further, a converter 37 for rectifying high frequency current into direct current is provided on the top plate 15, and its direct current output is supplied to the switch device 33. The switching device 33 preferably comprises a semiconductor switching element such as an SCR or a transistor and a timer (not shown) and is located between the charging station P and the stop position R of the next pocket 17 downstream thereof. It is configured to be triggered by a switch 38 (which may be any other switch, but a contactless switch is particularly preferred) to close for a time t, preferably determined by a timer, and to open after the time t has elapsed. ing. In addition, sudden ON,
If the structure of the high-frequency oscillation device in which OFF is used may have an adverse effect on the oscillation device, use a transistor switching circuit (for example, with an integrating circuit) that can turn ON and OFF relatively slowly. It is preferable to use time t
is equal to the time from when the heating coil 23 is energized until the thermal bonding is completed. Here, the term "completion of thermal bonding" means that the heat-fusible plastic film or heat-sensitive adhesive layer (not shown) of the thermally bonded portion on the surface of the lid part 3 or the opening end 2 is melted or heated to a sufficient degree for thermal bonding. Refers to a softened state. Since the heating rate due to high frequency induction heating is extremely high, the time t is usually in the range of 0.05 to 2.0 seconds.

The web cutter 10 is fixedly installed between an upper rotary disk 12 and a lower rotary disk 13 at a stopping position of a pocket portion 17 between a charging station P and a delivery station Q. The web cutter 10 has a die 39a.
It has an upper blade 39 fixed to the container body 1, and a lower blade 40 fixed to the support body (i.e., punch) 41, and their diameters are the same as the opening end 2 of the container body 1 in this embodiment.
The outer diameter of the lower blade 40 and its holder 4 is approximately equal to the outer diameter of the lower blade 40 (it may be slightly larger).
High frequency induction heating coil device 2 with stopped position 1
2 is installed on the fixed plate 39b so as to be directly below it. The holding body 41 includes a cam roller 42 and an eccentric cam 4
3. It is moved up and down by a drive device (not shown) via a drive shaft 44. Drive shaft 44 by drive device
The rotation of the central shaft 11 is synchronized with the intermittent rotational movement of the central shaft 11 by a mechanism (not shown), and at the same time as the central shaft 11 stops (may be slightly earlier), the support body 41 rises to remove the lid part 3 from the web 20. Punch out, approach the punched lid part 3 to the elastic sheet 26, vacuum adsorb it,
It is designed to descend by the time the center shaft 11 starts its next rotation. The dimensions of the eccentric cam 43 are determined so that the optimum position when the upper surface of the support body 41 is raised is slightly below the elastic sheet 26. The web 20 and the web scrap 20' are fed in the direction of arrow Y in synchronization with the rotation of the central shaft 11 by a feed reel and a take-up reel, which are not shown, respectively.

Thermal bonding is performed using the apparatus A described above in the following manner.

In order to perform high-frequency induction heating, at least one of the open end 2 and the lid 3 (ie, the web 20) must have a metal layer. In addition, in order to perform thermal bonding, at least one of the opposing surfaces of the opening end 2 and the lid 3 (i.e., the web 20) must be coated with a heat-fusible plastic film or a heat-sensitive adhesive layer (so-called hot-melt type adhesive). (including). Furthermore, the web 20 usually has a base layer with high gas barrier properties (not shown, such as metal foil or ethylene-vinyl alcohol copolymer, vinylidene chloride, etc.).
(films made of polyamide resin, polyester resin, etc.). Therefore, the open end 2 and the web 2
An example of combination 0 is as follows: (a) When the open end 2 is made of metal such as tin, the web 20 is made of a heat-fusible plastic film (for example, carboxylic acid-modified polyethylene) film and a biaxially stretched polyethylene terephthalate film. Or a laminate with aluminum foil,
(b) When the open end portion 2 is made of a heat-adhesive resin such as nylon 12, the web 20 is coated with a primer (a coating film for improving thermal adhesion, such as phenol).
Aluminum foil or iron foil (including surface-treated ones) coated with epoxy-based baked coating,
(c) If the opening end 2 is made of glass, the web 20
Examples include aluminum foil or iron foil coated with a heat-sensitive adhesive (for example, a mixture of ethylene-vinyl acetate copolymer with waxes and a tackifier).

First, by stopping the center shaft 11, the pocket portion 17
When the web cutter 10 stops at the upper part of the web cutter 10, the holder 41 of the web cutter 10 rises, punches the lid 3 from the stationary web 20, and then raises the lid 3 to approach and adsorb the elastic sheet 26. .
Next, the central shaft 11 rotates, the pocket part 17 reaches the loading station P, and when it stops, the container body 1 is immediately loaded onto the support plate 16 of the pocket part 17, and the open end 2 is inserted into the lid part. Located directly below 3. Next, by the time the pocket section 17 reaches the next stop position R, the cam roller 16a rises and the container body 1 also rises, and the opening end 2 heats the peripheral part of the lid 3 that comes in contact with it via the elastic sheet 26. Press against the coil 23. Since the elastic sheet 26 is present, a predetermined pressing force can be applied almost uniformly along the circumferential direction of the open end 2. Preferably, the proximity switch 38 is actuated immediately after said press (particularly to prevent overheating of the lid 3 when it has a metal layer), triggering the switch device 33 to energize the heating coil 23 and open the open end 2. And/or the metal layer of the lid part 3 is dielectrically heated. The heating continues for a predetermined time t until the thermoplastic plastic film or the heat-sensitive adhesive layer melts or softens and becomes ready for thermal bonding, that is, until the thermal bonding is completed. After the predetermined time t has elapsed, a timer in the switch device 33 is activated, the heating coil 23 is deenergized, and the heating coil 23 and the thermally bonded portion are cooled by the cooling water circulating through the cooling cannula 24. By the time the pocket portion 17 almost leaves the station S in front of the delivery station Q, the temperature of the heat-fusible plastic film or heat-sensitive adhesive layer of the heat-adhesive portion is lowered to a temperature lower than the melting point or softening point. After that, the cam roller 16a descends, the pressure is released, and the lid 3
The container 4 (FIG. 1) to which is thermally bonded is delivered from the delivery station Q. During this time, the web 20 moves forward by one pitch (a length slightly larger than the diameter of the lid portion 3). Note that if the lid part 3 does not have a metal layer, the heating coil 23 starts energizing at the delivery station Q.
It may be carried out at an appropriate time after leaving the press and immediately after pressing. However, in that case, the support 4
There may be cases where it is necessary to perform first class cooling.

Note that to feed power to the heating coil 23 of the high frequency induction heating coil device 22, the rotary transformer 32 shown in FIGS. 6 and 7 is used instead of the rotary transformer 32 shown in FIGS. 2 and 3.
A rotary transformer 46 of the type shown in FIGS. 2 and 3 (the same reference numerals as in FIGS. 2 and 3 indicate the same parts) may also be used. The rotating transformer 46 includes one primary coil 47, a magnetic core 48 having an E-shaped cross section (made of ferrite, for example), secondary coils 49 of the same number as the heating coils 23, and a magnetic core having an E-shaped cross section (made of ferrite, for example). ) 50. Each magnetic core 50 is fixed on the top plate 15 along a circular ring centered on the rotation center of the turret 9 with a slight gap 51 (to reduce leakage magnetic flux) from each other. The secondary coils 49 are connected to respective heating coils 23 . The arc-shaped magnetic core 48 is fixed in the current-carrying region of the heating coil 23 in close opposition to the magnetic core 50 by means of a support (not shown). The primary coil 47 is connected to a high frequency oscillator (not shown) via the feeder 52, and is constantly energized during operation. When the turret 9 is currently rotating in the direction of arrow X, the secondary winding 49 is connected to the inlet side 4 of the magnetic core 48.
When entering the lower part of 8a, the magnetic flux 53 passing through the magnetic core 48 due to the current flowing through the primary winding 47 passes through the inside of the magnetic core 50, so a secondary current is generated in the secondary winding 49, and the corresponding Heating coil 2 connected to secondary winding 49
3 (in the case of FIG. 6, the heating coil passing near station R) is energized. When the secondary winding 49 finishes passing through the exit side 48b of the magnetic core 48,
The heating coil 23 corresponding to the secondary winding is deenergized. Therefore, in this embodiment, the switch device 3
It has the advantage of not requiring 3.

According to the apparatus of the present invention, while intermittently moving a plurality of high-frequency induction heating coil devices provided along the turret, each heating coil device is used to continuously place the lid on the open end of the container body. Then, by pressing, thermally bonding, cooling, and releasing the pressure, a container with a thermally bonded lid is manufactured, and the time required for each step is extremely short (for example, by applying heat using high-frequency induction heating). Gluing end time is 0.05
~2.0 seconds), so it has the effect of achieving a high production rate of about 100 to 500 cans per minute. Further, according to the method of the present invention, since the pressure is released after the thermally bonded portion is cooled to a temperature lower than the melting point or softening point of the thermally adhesive layer, it is possible to ensure an airtight thermally bonded portion. Furthermore, the method of the present invention has the effect of realizing the above-mentioned high production rate by using a plurality of high-frequency induction heating coil devices.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an example of a container manufactured according to the present invention, FIG. 2 is a plan view of an apparatus that is an embodiment of the present invention, and FIG. 3 is a longitudinal sectional view taken along the line - in FIG.
Figure 4 is a cross-sectional view taken along the - line in Figure 2;
The figure is a plan view of the main part seen from the - line in Figure 2.
The figure is a plan view of a main part of an apparatus according to another embodiment of the present invention, and FIG. 7 is a longitudinal sectional view taken along the line - in FIG. 6. 1... Container body, 2... Opening end, 3... Lid, 4... Container, 9... Turret, 10... Web cutter (device for punching the lid from the web),
17...Pocket part, 18...Cam roller, 19
a...Cam groove (part of the device that presses the lid), 2
2... High frequency induction heating coil device, 23... Heating coil, 29... Vacuum suction hole, 32... Rotary transformer, 33... Switch device, 46... Rotating transformer, 47... Primary coil, 49... Secondary coil.

Claims (1)

[Claims] 1. A method for manufacturing a container in which a lid is thermally bonded to an open end of a container body, wherein the open end and/or
or the lid has a surface made of a thermal adhesive layer,
and at least one of the open end and the lid has a metal layer, and the method includes punching the lid from a web and performing high-frequency induction heating including a heating coil having a shape corresponding to the open end. A step of adsorbing the high frequency induction heating coil device to the coil device, a step of moving the high frequency induction heating coil device, a step of pressing the lid portion adsorbed to the high frequency induction heating coil device and the opening end, and energizing the heating coil to perform thermal bonding. step, deenergizing the heating coil after completion of thermal bonding, and releasing the pressure after the temperature of the thermally bonded portion has decreased to a temperature lower than the melting point or softening point of the thermally adhesive layer. A method for manufacturing a container whose lid is thermally bonded. 2. A device for thermally bonding a lid to an open end of a container body, the device having a plurality of pockets for storing and transporting the container body, and an intermittently rotating turret; A high frequency induction heating coil device including a heating coil having a shape corresponding to the end portion and having a vacuum suction hole; the lid portion provided opposite to the high frequency induction heating coil device at a fixed position where the pocket portion stops; A device for punching out the lid from the web; a device for bringing the punched lid close to the high-frequency induction heating coil device and adsorbing it; downstream of the punching device, the open end of the container body stored in the pocket; A device for pressing the opening end and the lid; a rotary transformer for supplying current from the high frequency oscillator to the heating coil; a device for supplying current from the rotary transformer to the heating coil; 1. A device for thermally bonding a lid to an open end of a container body, comprising: a switch device for deenergizing the heating coil after the heating coil is thermally bonded; and a device for releasing the pressure after the deenergization. 3. A device for thermally bonding a lid to an open end of a container body, the device having a plurality of pockets for storing and transporting the container body, and an intermittently rotating turret; A high frequency induction heating coil device including a heating coil having a shape corresponding to the end portion and having a vacuum suction hole; the lid portion provided opposite to the high frequency induction heating coil device at a fixed position where the pocket portion stops; A device for punching out the lid from the web; a device for bringing the punched lid close to the high-frequency induction heating coil device and adsorbing it; downstream of the punching device, the open end of the container body stored in the pocket; and a device for pressing the lid; a fixed primary coil connected to a high-frequency oscillator, and a plurality of secondary coils that can revolve while closely facing the primary coil, and the secondary coil is a rotating transformer connected to a corresponding heating coil and configured to energize the heating coil at an upstream end of the primary coil and deenergize the heating coil at a downstream end; and A device for thermally bonding a lid to an open end of a container body, characterized by comprising a device for releasing the pressure afterward.