JPH0260509B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lamination bonding apparatus for metal foil sheets, and more particularly to a lamination bonding apparatus for bonding oppositely laminated sheets by melting a plastic adhesive using high frequency induction heating.

Sheets made by laminating and adhering plastic sheets to metal foil sheets such as aluminum foil have a wide range of uses, as they are used as storage bags for food, drinking water, medicine, etc., and as lids for storage containers.

In order to bond the aforementioned metal foil sheet and plastic sheet or two metal foil sheets together via a plastic adhesive layer, conventionally a loop-shaped heating coil is placed near one side of the continuously running metal foil sheet. A high frequency current is supplied to the heating coil to heat the metal foil sheet to a desired temperature. Then, if another sheet is stacked on top of this heated metal foil sheet and pressed with a pressure roller, etc., the adhesive layer between the two sheets will adhere the two sheets, and a uniform lamination adhesive effect can be obtained. becomes possible.

As is well known, when heating a metal foil sheet, a certain amount of time is required for the adhesive layer to melt or to rise in temperature, and for this reason, there is no metal between the heater and the pressure roller. A gap is provided to allow time for the heated temperature of the foil sheet to be transmitted to the adhesive layer, and as the sheet runs between these gaps, the adhesive layer is heated to the desired temperature.

In the conventional device, only a large heating coil is provided as a high-frequency induction heating device to raise the temperature of the metal foil sheet from room temperature to the desired adhesive melting temperature at once, and the above-mentioned temperature transfer time is provided. In order to ensure the safety of the device and to avoid high-frequency induction in any part of the device other than the seat, a relatively large gap is provided between the heater containing the high-frequency induction heating coil and the pressure roller. In the conventional apparatus, a significant temperature drop that cannot be ignored occurs in the metal foil sheet before it is guided to the pressure roller, resulting in a phenomenon in which good adhesion cannot be obtained.

In particular, plastic adhesives require a relatively narrow temperature range for bonding; for example, for polypropylene adhesives, the temperature must be maintained within a range of 180 to 220 degrees during bonding, and temperatures above or below this range are fine. It was impossible to perform proper adhesion.

Figure 1 shows the temperature (θ) characteristics with respect to the running time (t) of the metal foil sheet in the conventional device.
During the heating period from _t0 to _t1 , the sheet faces the heating coil and undergoes high-frequency induction heating, causing a rapid temperature rise. Thereafter, at time _t2 , the metal foil sheet is guided to the pressure roller together with other sheets, but there is a drawback that the temperature of the metal foil sheet decreases during running for this delay time ( _tA ). For this reason, in conventional devices, when the temperature required for bonding is θ ₁ , the heater must heat the sheet to θ ₂ in order to compensate for the temperature drop during the lag time. Various drawbacks have arisen, such as adversely affecting the internal composition. When extra heating is applied to compensate for the aforementioned temperature drop during running, the disadvantage is that the adhesive is heated due to the aforementioned narrow appropriate temperature range of plastic adhesives, making it impossible to obtain a good adhesive effect. It was hot.

Furthermore, when granular plastic is used as the plastic adhesive described above, a suitable amount of time is required for the granular plastic adhesive to diffuse sufficiently tightly during the journey from the heater to the pressure roller; In the apparatus, it has been extremely difficult to obtain such a good temperature range and maintain the appropriate temperature at the same time.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide an improved metal sheet lamination bonding device that can obtain a reliable lamination bonding effect without increasing the heating temperature more than necessary. It's about doing.

In order to achieve the above object, the present invention involves high-frequency induction heating of a metal foil sheet while running, overlapping and pressing another sheet onto the metal foil sheet, and welding the two sheets together using a plastic adhesive between the two sheets. A laminating bonding device for metal foil sheets that includes a high-frequency induction heating coil disposed along the running path of the metal foil sheet between a main heater and a crimping machine installed near the running path of the metal foil sheet. It is characterized by the provision of an auxiliary heater.

Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows a preferred embodiment of the present invention, in which the metal foil sheet 10 is moved by the arrow A
The main heater 14 is installed near the path of the vehicle and is continuously heated by induction. The main heater 14 is a ferrite core 16
Heating coil 18 carried on and heating coil 18
The power source 20 includes a power source 20 that supplies a high frequency current to the.

The metal foil sheet 10 is guided to a pressure roller 22 provided in front of the main heater 14, and the pressure roller 22 is also guided by another plastic sheet 24 made of polypropylene film or the like or the metal foil sheet 1.
0 is guided from the direction of arrow B, and pressure roller 2
At step 2, both sheets 10 and 24 are pressed together, and at this time the adhesive coated on sheet 24 is melted to ensure that both sheets 10 and 24 are evenly bonded.

In the present invention, the adhesive is made of a plastic adhesive, for example, a modified polypropylene adhesive is used in the embodiments, and it is particularly preferable to use such a modified polypropylene granular adhesive.

The granular plastic adhesive used in the present invention preferably has a functional group in the molecule, such as a carboxyl group, a hydroxyl group, an amide group,
Particle size of polymers that are solid at room temperature and have acid anhydride groups, ester groups, urea groups, urethane groups, etc. from 0.1μ
A powder of 200μ, preferably 0.1μ to 100μ is good.

More specifically, the granular plastic adhesive used in the present invention includes organic acids such as maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, and acrylic acid, or their esters or metal salts, or maleic anhydride; Modified polyethylene, modified polypropylene, modified ethylene-propylene copolymer, modified poly-4 made by copolymerizing acid anhydrides such as citraconic anhydride and tetrahydrophthalic anhydride in a block or random manner.
- Modified polyolefin resin such as methylpentene-1, or a mixture of the modified polyolefin resin and unmodified polyolefin resin, nylon resin such as nylon 6, nylon 66, nylon-11, nylon-12, or a copolymer thereof, epoxy resin, Powders of polyester resin, polyester ether resin, fluororesin, etc. are suitable.

The granular plastic adhesive used in the present invention described above preferably has an adhesion amount of about 0.1 to 10 g/m ² , most preferably 1.0 to 5.0 g/m ² .

A characteristic feature of the present invention is that an auxiliary heater 26 including a high-frequency induction heating coil is disposed along the running path of the metal foil sheet 10 between the main heater 14 and the crimping device consisting of the heating roller 22. In the embodiment, the auxiliary heater 26 includes three auxiliary heating coils 28 , 30 , 32 , which are connected in series to an auxiliary power source 34 . In addition, the heating coils 28, 30,
32 are ferrite cores 36, 38, 40 respectively
It is supported by In the embodiment, the heating coil 18 and each auxiliary heating coil 28, 30, 32
The installation intervals between the heating coil 18 and the right end of the auxiliary heating coil 28, between the left end of the coil 28 and the right end of the coil 30, and between the left end of the coil 30 and the left end of the coil 32 are set at equal intervals. They are set at approximately equal intervals. According to this arrangement, the temperature drop between the auxiliary heating coils becomes constant, and the auxiliary heating coils 28 and 3 connected in series
This has the advantage that stable temperature compensation can be achieved with uniform heating energy of 0.32. however,
In the present invention, these intervals can be set arbitrarily.

Further, in FIG. 2, the rotational speed of the feed roller 12 is detected by a speed detector 42 such as a tachometer generator, and the temperature of the metal foil sheet 10 immediately before being guided to the pressure roller 22 is detected by a radiation thermometer 44 or the like. be measured.

The embodiment of the present invention has the above configuration, and its operation will be explained below.

Fig. 3 shows the heating characteristics of Fig. 2,
The metal foil sheet 10 is heated at a position facing the main heater 14 between times t ₀ and _{t 1} to a temperature θ ₂ slightly higher than the temperature θ ₁ required for bonding. In the embodiment, this heating temperature is preferably set to about 200° C. within the optimum heating temperature range of 180° to 220°. Then, due to the feeding action of the feeding roller 12, the sheet 1
0 moves and a temperature drop occurs between time _t1 and _t2 , but
At time _t2 , the sheet 10 faces the auxiliary heating coil 28 of the auxiliary heater 26, and is heated to a temperature _θ2 between times _t2 and _t3 . Similarly, for the temperature drop from t ₃ to _{t 4} , heating is performed by the auxiliary heating coil 30 from t ₄ to _{t 5} , and for the temperature drop from t ₅ to _{t 6} , heating is performed by the auxiliary heating coil 32. Finally, at time _t8 , the temperature of the metal foil sheet 10 guided to the pressure roller 22 is maintained at the required temperature _θ1 .

In the embodiment, the above-mentioned auxiliary heating coil 2
While the plastic adhesive is maintained at a predetermined temperature by auxiliary heating by 8, 30 and 32, the modified polypropylene granular adhesive is heated sufficiently and uniformly and is uniformly spread over the surfaces of both sheets 10 and 24. , the quality of adhesion by the pressure roller 22 can be significantly improved.

As described above, according to the present invention, the main heater 14
The metal foil sheet 10 is heated to an unnecessarily high temperature by
There is no need to heat the heating device, making it possible to use an efficient heating device.

In the present invention, it is sufficient for the auxiliary power source 34 to have a capacity smaller than that of the power source 20, and the heating energy given to the sheet 10 by the auxiliary heater 26 also applies to the main heater 14.
Since the value is extremely small compared to
The sheet 10 can be guided to the pressure roller 22 while maintaining the zero temperature at a desired temperature.

In the present invention, the power source 20 and the auxiliary power source 3
In order to perform the power control in step 4, electrical power control is performed using the feeding speed of the sheet 10 or the temperature at the time of introduction to the pressure roller 22 obtained from the speed detector 42 or the radiation thermometer 44 described above. Experimentally, it has been found that it is preferable to make the power supply voltage of the main heater 14 proportional to the square root of the feeding speed of the sheet 10. Then, once the auxiliary heater 2
If the power energy given from 4 is determined,
Even if the feeding speed of the sheet 10 is changed thereafter, the auxiliary heating and temperature reduction will change corresponding to the change in the feeding speed. That is, when the feeding speed becomes lower, the amount of temperature reduction will also increase, but on the other hand. In this case, the auxiliary heating temperature also increases, and by maintaining a balance between the two, it becomes possible to maintain the desired heating temperature regardless of the feeding speed of the sheet 10.

In the embodiment described above, three auxiliary heaters 26 are used.
Although these heating coils are used, the number of installed heating coils can be set arbitrarily, and the interval between each heating coil can also be changed as necessary.

As explained above, according to the present invention, there is no need to heat the sheet to an unnecessarily high temperature, internal deformation of the sheet due to overheating is eliminated, and thermal decomposition of the adhesive is prevented, thereby ensuring reliable lamination. It becomes possible to perform adhesion.

In particular, in the case of using a granular plastic adhesive in the present invention, the granular plastic can be sufficiently uniformly heated during the auxiliary heating period by the auxiliary heating coil and uniformly diffused over the adhesive surface, resulting in a good adhesive effect. It becomes possible to obtain.

[Brief explanation of the drawing]

Fig. 1 is a heating characteristic diagram of a conventional bonding device, Fig. 2 is a schematic configuration diagram showing a preferred embodiment of the laminated bonding device according to the present invention, and Fig. 3 is a heating characteristic diagram of the embodiment of Fig. 2. be. 10... Metal foil sheet, 14... Main heater, 1
8... Heating coil, 22... Pressure roller, 26...
...Auxiliary heater, 28, 30, 32...Auxiliary heating coil.

Claims (1)

[Claims] 1. In a metal foil sheet lamination bonding device that heats a metal foil sheet while running it by high frequency induction, overlays another sheet on the metal foil sheet and presses it, and welds both sheets with a plastic adhesive between the two sheets, A granular plastic adhesive is used as the adhesive, and the heating temperature is controlled by the main heater, which is disposed along the running path of the metal foil sheet between the main heater and the crimping machine, which is installed near the running path of the metal foil sheet. The metal foil sheet is provided with an auxiliary heater including a high-frequency induction heating coil for preventing a decrease in temperature and increasing the heating temperature transmission time to the adhesive to uniformly melt and diffuse the granular plastic adhesive over the surface of the metal foil sheet. Foil sheet lamination adhesive device.