JPH04126223A - Curing method for adhesive - Google Patents

Abstract

PURPOSE:To shorten the curing time of adhesive, improve productivity and, at the same time, eliminate or downsize a thermostatic chamber for curing by a method wherein metal foil layer is ohmic treated by energizing between the outer end and the inner end of a laminated coil until the temperature of the laminated coil reaches at least its curing temperature. CONSTITUTION:Laminate consisting of a laminated coil 1 has three-layered structure produced by respectively bonding polyethylene terephthalate film and polypropylene film through isocyanate-based adhesive to both sides of aluminum foil by dry lamination and conducting tabs 3 and 4, which are respectively pinched between layers at the outer end side and the inner end side of the coil 1. By pinching the tabs 3 and 4 with clips, a close circuit running through a DC source 16, a lead wire 18, the aluminum foilin the coil 1 and a lead wire 20 is formed. When the, aluminum foil layer is ohmic heated by flowing DC current at the predetermined voltage through the energizing tabs 3 and 4 in the aluminum foil layer in the coil 1, the temperature within the coil 1 can be raised up to nearly curing temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to a method for manufacturing retort pouches, etc.
The adhesive of the laminate consisting of the metal foil layer and the plastic film layer is cured in the form of a coil.

(Prior art) Laminated body 1 that becomes the original fabric of a retort pouch, for example, RP-F
(registered trademark, Toyo Seikan■) has a three-layer structure of saturated polyester, metal foil (usually aluminum foil), and polyolefin film, or a four-layer structure of saturated polyester, nylon, metal foil, and polyolefin film. Each layer is bonded with an isocyanate adhesive.

This type of laminate is laminated by the so-called dry lamination method, and the laminate is wound into a coil at about 20 to 30°C to improve the heat-resistant adhesion of the adhesive. C large size (e.g. content width: approx. 1600
The laminate, which had been kept in a constant temperature room (for example, Japanese Patent Application Laid-open No. 52-81391) for 4 to 7 days, heated to a high temperature in the drying oven (see 11 in Figure 2) of a dry lamination device, is heated to a high temperature. If the coil is wound as it is, wrinkles will occur in the coil, so the three-layered product is usually cooled to about 25 to 30° C. before being wound into a coil.

After being housed in a thermostatic chamber, the temperature of the coil increases due to heat conduction, but the coil is relatively large, for example, with an outer diameter of 60 to 100 cm and an inner diameter of about 20 cm.

When the radius is about 100 cm), it takes about 2 days for the area where the temperature rises the slowest (usually the center of the coil in the radius direction and thickness direction) to reach the curing temperature of 50 °C.Isocyanate-based adhesive Since the minimum required intermediate time of the agent at 50° C. is about 3 days, the number of days of storage in the constant temperature room is 5 days in this case.

Storing in a constant temperature room for such a long period of time reduces productivity, and if the number of laminates to be produced is large (or if there are many coils to be cured, a large constant temperature room as mentioned above is required). This creates the problem of

(Problems to be Solved by the Invention) In the present invention, each layer is bonded using a reaction curing type adhesive such as an isocyanate adhesive.

The time required to reach the curing temperature of the adhesive, and/or the curing time, and/or the cooling time after curing of a laminate coil consisting of a metal foil layer and a plastic film layer can be shortened to improve overall kissing and assembly. The purpose of the present invention is to provide a method for curing an adhesive for a laminate coil, which shortens the time required for curing, improves productivity, and eliminates or reduces the size of a thermostatic chamber for curing.

In this specification, what is meant by reaction curing type adhesive?

It refers to a type of adhesive that hardens through a chemical reaction (i.e., a cow core), and examples thereof include evo-cow adhesives, isocyanate-based adhesives, urethane-based adhesives, and mixtures thereof. Cure speed is accelerated by heating.

(Means for Solving the Problems) An object of the present invention is to energize the metal foil layer between the outer end and the inner end of the coil until the laminated coil reaches approximately the cow core temperature. Achieved by resistance heating.

Note that in this specification, the term "outer end of the coil" includes a portion near the outer end of the coil, and the term "inner end of the coil" includes a portion near the inner end of the coil.

At least during the curing period, that is, at least during the period in which the laminate coil is kept at the curing temperature, it is preferable to externally heat a portion near the outer circumferential surface, a portion near the side surface, and/or a portion near the inner circumferential surface of the coil.

After curing is completed, it is preferable to forcefully cool the coil.

In this case, forced cooling is preferably performed by bringing the 0 unwinding portion into contact with a cooling roll while unwinding the coil.

It is preferable that the current to be applied is a direct current. When the current to be applied is an alternating current, it is preferable to conduct the current so that the phases of the currents flowing on both sides of the substantially central portion in the thickness direction of the coil are shifted by 180 degrees.

Preferably, the resistance heating is controlled based on the electrical resistance between the outer and inner ends of the coil.

For external heating near the inner peripheral surface, a metal pipe, a metal sheet, or a pipe covered with a metal mesh is used as the winding core of the laminated coil, and the metal pipe, metal sheet, or metal mesh is heated by electric induction. It is preferable to do so.

(Function) Electricity is applied to the metal foil layer between the outer end and the inner end of the coil to resistance heat the metal foil layer at least until the coil reaches approximately the curing temperature. That is, by internal heating, a cure temperature of 1, for example 50° C., can be reached in about 30 to 90 minutes. Therefore, the time required to reach the beef core temperature is significantly reduced, and the overall curing time is reduced. Therefore, when the coil that has reached the curing temperature is placed in a thermostatic chamber for curing, the thermostatic chamber can be downsized.

Because heat is dissipated near the outer peripheral surface, inner peripheral surface, and side surface of the coil, the temperature rises slowly when the temperature is raised by resistance heating, and the temperature decreases during the curing period, which tends to result in insufficient curing. By externally heating a portion near the outer circumferential surface, a portion near the side surface, and/or a portion near the inner circumferential surface of the coil for a period of time, it becomes possible to cure the entire coil at a substantially uniform temperature. As a means of external heating, in addition to a constant temperature room, a flexible planar heating element, etc., which will be described later, is used.
I can do it. Therefore, it is also possible to perform curing without using a constant temperature room.

If a constant temperature room is not used as in case C, it is possible to set the curing temperature to 80°C or 100°C, for example. etc.), in which case the net curing temperature can be significantly reduced. That is, if the minimum required curing time is 3 days at 50°C, this time may be 1 day at 80°C.

By forcibly cooling the coil after curing the adhesive, the overall curing time can be further shortened. In this case, force cooling is performed while unwinding the coil.
When the unwinding portion is brought into contact with a cooling roll, the cooling time is equal to the unwinding time, so the cooling time is significantly shortened.

When direct current is applied, there is no need to supply reactive power (power efficiency is improved).

When alternating current is applied so that the currents flowing on both sides of the coil in the thickness direction are 180 degrees out of phase,
Since the directions of the magnetic fluxes based on the currents flowing outside and inside the central portion are opposite to each other, the magnetic fluxes cancel each other out, improving the power factor and improving power efficiency.

The electrical resistance between the outer and inner ends of the coil is a function of the temperature of the metal foil layer of the coil. Therefore, resistance heating can be controlled based on the electrical resistance without using a thermal sensor.

By externally heating the area near the inner peripheral surface of the coil by electric induction heating, the area near the inner peripheral surface can be efficiently, uniformly, and easily heated to and maintained at the curing temperature.

(Example) In Fig. 1, 1 is a laminate coil, and the laminate forming the coil 1 is made by dry laminating a polyethylene terephthalate film and a polypropylene film on each side of aluminum foil using an isocyanate adhesive. It has a three-layer structure bonded together using a method.

As shown in Example 2 below, the coil 1 may have a four-layer structure.The coil temperature immediately after winding is approximately 25~25.
It is 30°C. 2 is a winding core of the laminate, and 1
It is usually made of paper, that is, a paper tube (the thickness of the paper is about 20 mm).

Reference numerals 3 and 4 denote current-carrying tabs sandwiched between the outer and inner ends of the coil 1, respectively, and preferably include a highly conductive metal foil 1 having a pressure-sensitive adhesive layer on one side, for example, a thickness of about 10 mm.
It is made of aluminum foil with a thickness of ~200 νm.

This clamping of the tabs 3.4 is preferably carried out as shown in FIG. FIG. 2 shows the main parts of the dry lamination device.

5 is a web of polyethylene terephthalate, 6 is a first drying oven, 7 is a web of aluminum foil, 8 is a first drying oven.
9 is a first cooling roll, 10 is an adhesive applicator, 11 is a second drying oven, and 12 is a polypropylene web.

13 is a second laminating roll, and 14 is a second cooling roll.

On the upper surface of the polyethylene terephthalate web 5 that has left the first drying oven 6, a film of incyanate adhesive that has been applied and dried is formed, leaving a width of about 10 mm at the edge. After the web 5 and the aluminum foil web 7 are laminated by a laminating roll 8, an adhesive is applied to the surface of the aluminum foil web 7 by an adhesive coating device 10, leaving a width of about 5 mm at the edge, and the adhesive is applied. The agent is dried by a second drying oven 11.

Next, the polypropylene web 12 is laminated on the surface of the aluminum foil web 7 by a second laminating roll to form a laminate web 15.
is wound around a winding core 2 to form a coil 1.

At the beginning of winding and at the end of one winding (although it is shown midway in the figure), on the upstream side of the first laminating roll 8, the pressure-sensitive adhesive layer side surfaces of the tabs 3 and 4 are connected to the edges of the web 5. The tab 3.4 can be sandwiched between the coils by adhering the tab 3.4 to the web 5 so as to protrude approximately 10 to 50 mm from the side edge of the web 5. As further shown in FIG. 2, instead of web 5, tabs 3 and 4 may be adhered to polypropylene web 12 in a manner similar to that described above.

In this case, the tab 3.4 comes into conductive contact with the edge portion of the aluminum foil web 7 having a width of about 5 mm, but this does not cause any problem in current supply.

Returning to FIG. 1, 16 is a DC power supply with a control device.

17 is a rectifier 9 such as a thyristor, and 18 is an AC power supply. Clips (not shown) are attached to both ends of the conductive wires 19 and 20 connected to the DC power source 16, respectively, and by sandwiching the tabs 3 and 4 with the clips, the DC power source 16. Conductor】9. A closed circuit is formed through the aluminum foil 7 in the coil 1 and the conductor 20.

Depending on changes in various factors such as the dimensions of the coil 1 and the thickness of each layer of the laminate, a DC current is applied to the aluminum foil layer in the coil 1 via the current tab 3.4 at a voltage determined by experiments in advance. By applying current to resistance heating the aluminum foil layer, the temperature inside the coil I can be raised to about the cow core temperature 9, for example, about 50° C., in about 30 to 90 minutes.

In this case, the temperature rise in the vicinity of the outer peripheral surface, the inner peripheral surface, and the side surface of the coil 1 is delayed due to heat radiation. However, if the coil 1 is placed in a constant temperature room (for example, kept at 50°C) after being resistance heated until it reaches the curing temperature as described above, the portion where the temperature rise is delayed is It is a part that easily receives heat transfer by air, and moreover, it reaches the curing temperature relatively quickly due to heat conduction from inside the coil. Therefore, the overall curing time is significantly shortened (by approximately 2 days).

Note that resistance heating may be performed in a constant temperature room during the temperature raising period, and resistance heating may be performed in combination in the constant temperature room during the curing period.

Coil 1 whose internal temperature has reached the cure temperature due to resistance heating
The adhesive may be cured by lowering the voltage of the power supply 16 and continuing resistance heating with a relatively small electric power for heat retention, without placing the coil in a constant temperature room. In order to prevent a delay in the temperature increase near the inner peripheral surface and the side surfaces, and to prevent cooling of these parts due to heat radiation during the curing period, external heating without using a thermostatic chamber (hereinafter referred to as direct external heating) is performed. During the heating period and/or the curing period, it is preferable to maintain a portion near the outer peripheral surface, a portion near the inner peripheral surface, and a portion near the side surface of the coil 1 almost at the curing temperature.

During the curing period, only direct external heating is applied.

Resistance heating may not be required; in this case, it is also preferable to use direct external heating during the heating period.

Direct external heating of the area near the outer circumferential surface and the area near the side surface 3. For example, a resistance heating element is embedded and the inner surface temperature is approximately the curing temperature or a temperature slightly higher than that (for example, about 2
Preferably, a means is used in which the entire coil 1 is covered with a flexible planar heating element (not shown) maintained at a temperature of 0.degree. Alternatively, a method is adopted in which the coil 1 is placed in a box (see 30 in Figure 3) and the space temperature inside the box is maintained at the above temperature by blowing hot air into the box or by embedding a heating element in the box. be done.

A direct external heating method for the vicinity of the inner circumferential surface is a method in which a resistance heating element is embedded in the winding core 2 made of a paper tube and the temperature of the outer circumferential surface is maintained at approximately the curing temperature.

Alternatively, the outer peripheral surface of the paper tube core 2 may be covered with a metal sheet or metal mesh (preferably a mesh of about #100 made of stainless steel wire of 0.1 to 0.2 mm), or the core 2 may be covered with a metal pipe core. 2 using a high frequency induction heating coil provided within the core 2.

Alternatively, it is preferable to use a means of heating and holding the metal sheet, etc. to approximately the curing temperature by passing an alternating current through the coil 1 and inductively heating the metal sheet, mesh, or metal pipe.

In these cases, heat sensors are inserted into the vicinity of the outer circumferential surface of the coil 1, the interior and the vicinity of the inner circumferential surface, and the vicinity of the side surfaces of the coil 1 to maintain the temperature of each part at the curing temperature. It is desirable to control the current of the heating element, the current supplied from the power source 16, the current of the resistance heating element of the winding core 2 or the high frequency induction heating coil, etc. The temperature near the outer peripheral surface and near the side surface is lower than the set curing temperature. It may be slightly higher or lower.

When performing direct external heating, a heat sensor is installed only near the outer peripheral surface of coil 1, and the temperature of the entire coil is maintained at the set cure temperature based on data obtained by experimentally controlling the current as described above. It is practically preferable to control the heating conditions of the outer circumferential surface, side surface, and inner circumferential surface of the coil 1, as well as the resistance heating conditions, so that the heating conditions are controlled as follows.

Next, an example of a more preferable resistance heating control method when direct external heating is performed will be described.

In FIG. 3, 30 is a heat insulating box with a built-in heating element (not shown), which is heated by a power source 31 (for example, a commercial frequency AC power source). The output signal 43 of the temperature sensor 32 that measures the outer peripheral surface temperature T, and the average temperature T of the metal foil layer described below.
The signal 37 based on . The comparator 33 has T, <
The T open signal 44 is output to a PID type control device (not shown) built in the power supply 31, and the power supply 31 is turned on. The control device is configured to control the output current of the power source 31 so that the temperature near the outer peripheral surface and the side surface of the coil 1 becomes substantially equal to the temperature T.

34 is a computing unit, and a tab 3.4 for energizing is connected to the power supply 16.
A current value signal 35 and a voltage value signal 36 of the current flowing through the metal foil layer of the coil 1 are input. The calculator 34 performs the following calculation based on the principle that the resistivity of metal is a function of temperature.

The average temperature (T;'C) of the metal foil layer due to resistance heating is calculated.

R=V/I...(1) where R is the electrical resistance of the metal foil layer between tabs 3 and 4 ■ is the voltage (volts) between tabs 3 and 4 ■ is the current flowing through the metal foil layer (ampere) p = Rx
t x w / Q - (2) where ρ is the specific resistance of the metal foil (Ω m) t is the thickness of the metal foil layer (m) W is the width of the metal foil layer (m) 9 is the tab of the metal foil layer Length between 3 and 4 (m) T = f (ρ)
-.(3) Here, f is a function indicating the relationship between ρ and T.

A signal 37 of the temperature T converted into a voltage value from the calculator 34
is input to the first terminal of comparator 38.

On the other hand, the set cure temperature T is converted into a voltage value. signal 39
is input to the second terminal of comparator 38. Comparator 38 compares temperatures T and Te, between TNT.

A signal 39 is output to a PID type control device built into the power supply 16. In this way, it is possible to insert (it is impractical to insert) a thermocouple into the inside of the coil 1 (for example, the positions corresponding to points b and C in FIG. 1, see Example 1). The internal temperature can be controlled to a set curing temperature.

In addition, the heat capacity of the coil 1, the set heating time, and the curing temperature T. Calculate the required power (kw) from , and based on this power, determine the voltage and current to be supplied from the total length, width, and thickness of the aluminum foil layer, respectively, and calculate T = Tc
You can turn off the power supply 16 when the
Does not require control.

40 is a power source (such as a high frequency oscillator) for heating a heating element (not shown) such as a metal mesh provided in the 1-winding core 2; 42 is a comparator; Output signal 45 of temperature sensor 41 that measures temperature T1
．． and a signal 37 based on the average temperature T of said metal foil layer.
enters.

The comparator 42 outputs a signal 46 to a PID type control device (not shown) built in the power supply 40, and turns on the power supply 40 while ① is smaller than T (T,<T). The control device is configured to control the output current of the power source 40 so that the temperature near the inner peripheral surface of the coil 1 becomes substantially equal to the temperature T.

By heating and keeping warm while controlling the parts near the outer peripheral surface, the parts near the side surfaces, the parts near the inner peripheral surface, and the inside of the coil 1 in this way, the entire coil 1 can be heated as described in Specific Example 2 below. can be substantially uniformly heated to the curing temperature and maintained at the curing temperature.

In the case of a type of laminate whose length increases as the temperature rises (for example, the three-layer structure laminate shown in Example 1 below), after curing, these currents are cut off all at once and the one-sided heating element or heat insulation box is When removed, cooling begins from the outer circumferential surface of the coil 1, so that after the entire coil has cooled to room temperature, the coil 1 is tightly wound (tightly wound and wrinkles in the axial direction are likely to occur).

In order to prevent this, the temperature near the inner peripheral surface of the carp J is kept slightly lower than the set curing temperature during the curing period.
Moreover, it is preferable to gradually cool the coil 1 from the inner circumferential surface side toward the outer circumferential surface side.

To do this, first turn off the current to the resistance heating element or high-frequency induction heating coil of the winding core 2, and then turn off the current to the power supply.
6, and finally, it is desirable to turn off the current to the heating element in the heat insulating box or remove the heat insulating box.

In the case of a type of laminate that shrinks in length due to temperature rise (for example, a 4-layer laminate shown in Example 2 below), the above-mentioned wrinkle problem is unlikely to occur, so the above-mentioned work considerations should be taken. However, in the case of the 1.4-layer laminate described above, the reason why the length shrinks due to temperature rise is that the stretched nylon undergoes a large heat shrinkage during the laminate formation.

Since it takes a long time to naturally cool the coil l while it is coiled, cool air is blown onto the outer circumference and sides of the coil.
Further, it is desirable to forcibly cool the coil by passing cold air through the core 2 or by bringing the coil into contact with a cooling roll while unwinding it as shown in FIG. 4.

In FIG. 4, reference numerals 51 and 52 are cooling rolls, each of which includes outer cylinders 51a and 52a (for example, made of a copper pipe with a chromium-plated surface) and a cooling water 53 (for example, 1
It has inner holes 51b, 52b through which air (at 0°C) flows. The laminate web 15 is wound around the cooling roll 51.52 in an S-shape and is unwound in such a way that the contact area with the cooling roll 51.52 is made as thick as possible.

From the coil 1 (not shown in FIG. 4) cured in this way, for example at 100°C, the laminate web 15
While being rewound at high speed in the direction of the arrow, the cooling roll 51
．． After being rapidly cooled to e.g. 30°C by 52,
It is again wound into a coil by a winding device (not shown). Note that the number of cooling rolls may be one or three or more.

When heating the inner peripheral surface of the coil by high-frequency induction heating, it is dangerous because high-frequency voltage is induced in the coil, so it is preferable to perform high-frequency induction heating only when resistance heating is being performed. This is because the outer ends are short-circuited at high frequency and the induced voltage is reduced.

When applying an alternating current to the coil 1, if the current is applied directly from the outer end to the inner end of the coil (i.e. in the manner shown in Fig. 1),
Supplying reactive power based on inductance increases power losses and poses risks associated with increases in power supply voltage. Therefore, when applying AC current, in addition to the 9 current-carrying tabs 3.4, insert the current-carrying tab 21 at the center position in the thickness direction of the coil, as shown in Fig. ) and each tab 3, 4 and 21 is preferably connected.

By doing this, the phase of the current flowing through the aluminum foil part between tabs 3 and 21 and the current flowing through the aluminum foil part between tabs 4 and 21 is shifted by 180 degrees, so that the current flowing through each part is Since the resulting magnetic fluxes cancel each other out, reactive power is reduced.

Next, a specific example will be described.

Specific example 1 A 12 μm thick polyethylene terephthalate film is placed on one side of a 7 μm thick aluminum foil, and a 70 μm thick polyethylene terephthalate film is placed on the other side.
A coil 1 consisting of a laminate made of polypropylene films of 100 to 100 mm was bonded together using an isocyanate adhesive was produced by a dry lamination method. The width of coil 1 is 64cm
The outer diameter was 60 cm, the inner diameter was 20 cm, and the total length of the laminate was 3000 m.

When winding into a coil, as shown in Fig. 1, energizing tabs 3 and 4 are inserted at a length of about 40 m from the outermost and innermost ends of the coil, respectively, and the tips of both are connected to the coil. The surface of the 9-wound core 2 is located at the center in the width direction (position a corresponding to point a in Figure 1), and the position 1000 m from the end of the coil stack (corresponding to point b in Figure 1). position b, the radial distance between points a° and b° is 9°5cm) and a position 2500 m from the above inner end (position C corresponding to point C° in Figure 1, point a° and C A thermocouple was inserted between the points (radial distance between points was 19 cm).

With both ends of the winding core 2 supported by supports (not shown) and the coil l suspended, the switch of the control device of the power supply 16 shown in FIG. Electricity was applied between tabs 3 and 4 to perform resistance heating of coil 1, and after 90 minutes of electricity, the current was turned off. of each part in between, that is, position a.

The temperature changes in b, c and d are shown in a and b in Fig. 6, respectively.
, c and 6 curves, the temperature at the center surface of the coil in the width direction (point d in FIG. 1) was measured using a radiation thermometer. As shown in Fig. 6, the slowest temperature rise at approximately the center in the thickness direction and width direction of the coil l reaches 50° in about 70 minutes.
It can be seen that C is reached.

Then, a similar coil 1 (without the thermocouple inserted) was resistance heated for 70 minutes under the same conditions as above.

The cows were immediately placed in a constant temperature room at 50° C. for 3 days and glued to the cow core. After curing, coil 1 was taken out of the constant temperature room and allowed to cool naturally. Samples were cut out from the laminate portions corresponding to the outer end, center, and inner end of the cooled coil and tested for peel adhesion strength (peel speed: 300 mm/min), and all values were normal.

Specific example 2 On one side of aluminum foil with a thickness of 7 μm, a thickness of 1 μm is applied from the outside.
A coil 1 consisting of a four-layer laminate consisting of a 2 μm polyethylene terephthalate film, a 15 μm thick nylon film, and a 50 μm thick polypropylene film on the other side bonded together using an isocyanate adhesive was produced by a dry lamination method. The width of coil l]
The outer diameter was 60 cm, the inner diameter was 20 cm, and the total length of the laminate was 3500 m.

When winding the coil into a coil, the energizing tabs 3 and 4 were inserted at positions approximately 10 m in length from the outermost and innermost ends of the coil, respectively, according to the method shown in FIG. As shown in Fig. 3, a magnetically shielded thermocouple 41 is inserted onto the outer surface of the two-winding core 2 so that its tip is located at the center in the width direction of the coil, and a thermocouple 32 is fixed on the outer circumferential surface of the coil. did.

An induction heating coil was inserted into the core 2 made of paper tube, and the outer surface of the core was wrapped with a #100 mesh metal net made of stainless steel wire with a diameter of 0.1 mm. The heat insulating box 30 used had a built-in resistance heating element, an air agitator, a supporting device described below, and a hinged top lid. Power supply] DC power supply as 6, 50Hz, 200V as power supply 31
AC power source was used.

A high frequency oscillator of 30 K) Iz and 2 kW was used as the power source 40 and connected to the heating coil.

Both ends of the wound core 2 were supported by supports (not shown), and the coil 1 was placed in a suspended state in a heat insulation box 30 as shown in FIG. 3.

In addition, in order to measure the temperature distribution inside the coil, the tip of each coil was positioned at the center in the width direction of the coil, and at a distance of 1000 m from the innermost end of the coil.

Thermocouples were inserted at lengths of 2000 m and 3000 m.

Cow core temperature T: 100°C9 Cure time: 15 hours
The cow core of coil I was conducted using the control method shown in FIG. As shown in FIG. 7, it was found that the entire coil was heated and cured substantially uniformly. In Figure 7, lines 1.2.3 and 4 are 1000 m and 2000 m from the core surface and the innermost end of the coil, respectively.
, and the temperature at a position of 3000 m.

Note that the power supplied from the power supplies 16.31 and 40 during temperature rise is 10.2 kw (constant), respectively.
Okw (initial value; gradually decreases), and 1.6kw
(initial value, gradually decreases), the power supplied by the power supply 16 during the curing period is 0, and the power supplied by the power supplies 31 and 40 is 0.
The supplied power was 300-500w.

After curing, open the top lid of the box 30, take out the coil 1, and as shown in Fig. 4, while unwinding the coil 1 at a speed of 100 m/min, cool the cooling rolls 51 and 52 (diameter 100 cm, cooling water temperature Coil 1 was forcedly cooled at 10°C. The web temperature immediately after leaving the roll 52 is 3
It was 0°C.

Samples were cut out from both ends and the center in the width direction of the web portion corresponding to the outer end, center, and inner end of the coil after cooling, and peel adhesive strength (peel speed 300 mm/min) was tested, but all values were normal. there were. No wrinkles were observed in the coil after cooling.

The present invention is not limited by the above embodiments, but 1
For example, the plastic film and metal foil layer may be of any suitable type, i.e. the metal foil layer may be an electrolytic iron foil or steel foil, and the plastic film and metal foil that make up the coil laminate may be of any suitable type. It can also be a layer.

Furthermore, as a direct external heating method for the vicinity of the inner surface of the coil, hot air or hot air may be circulated inside the core 2 to maintain the temperature of the core at approximately the curing temperature.

(Effects of the Invention) The invention as claimed in claim 1 significantly reduces the time required for curing the reaction curing type adhesive for the laminate coil as a whole, thereby improving productivity and reducing the need for a constant temperature room for curing. This has the effect of eliminating unnecessary or downsized humans.

In addition to the effect of the invention as set forth in claim 1, the invention set forth in claim 2 has the effect that the entire laminate coil can be cured substantially uniformly.

The invention according to claim 3 can shorten the cooling time after curing, and therefore can shorten the time required for curing as a whole.
It has the effect of being able to move.

The invention according to claim 4 has the effect that the cooling time after curing can be significantly shortened, and therefore the time required for curing as a whole can be significantly shortened.

The invention according to claim 5 has an effect that the power efficiency is higher than that when alternating current is applied.

The invention according to claim 6 has the effect that the power factor and power efficiency are improved.

The invention as set forth in claim 7 has the effect that resistance heating can be controlled based on the temperature inside the coil without inserting a thermocouple inside the coil.

The invention as set forth in claim 8 has the effect that the vicinity of the inner circumferential surface of the coil can be efficiently, uniformly, and easily heated and maintained at the curing temperature.

[Brief explanation of the drawing]

FIG. 1 is an explanatory perspective view showing an example of wiring when direct current is applied to the laminated coil in the present invention, and FIG. 2 is an explanatory perspective view showing an example of a method for inserting a current-carrying tab into the laminated coil. A front view of the main parts of an example of a dry lamination machine, Fig. 3 is an explanatory circuit diagram of an example of a heating control device for curing a laminate coil, and Fig. 4 shows a laminate coil after a cow core. Fig. 5 is a front view showing an example of the wiring when applying alternating current to the laminate fill, and Fig. 6 is a longitudinal sectional view of the main part of an example of a device for forced cooling. Time-
A diagram showing a first example of temperature relationship. FIG. 7 is a diagram showing a second example of the time-temperature relationship when the laminated coil is energized. DESCRIPTION OF SYMBOLS 1... Laminated body coil, 3, 4. 21... Current-carrying tab, 16... DC power supply, 22... AC power supply, 51.52
...Cooling roll. Figure +5 Figure time (minutes)

Claims (8)

[Claims] (1) A method for curing the adhesive of a laminate coil consisting of a metal foil layer and a plastic film layer in which each layer is bonded by a reaction-curing adhesive, at least until the coil reaches approximately the curing temperature. energizing the metal foil layer between the outer and inner ends of the coil;
A method for curing an adhesive for a laminated coil, the method comprising resistively heating the metal foil layer. (2) The method for curing an adhesive for a laminate coil according to claim 1, wherein a portion near the outer peripheral surface, a portion near the side surface, and/or a portion near the inner peripheral surface of the laminate coil is externally heated at least during the curing period. (3) The method for curing an adhesive for a laminate coil according to claim 1 or 2, wherein the laminate coil is forcibly cooled after curing. (4) The method for curing adhesive for a laminate coil according to claim 3, wherein the forced cooling is carried out by bringing the unwound portion into contact with a cooling roll while unwinding the laminate coil. (5) The method for curing an adhesive for a laminated coil according to claim 1 or 2, wherein the applied current is a direct current. (6) The method for curing an adhesive for a laminated coil according to claim 1 or 2, wherein the applied current is an alternating current, and the phases of the currents flowing on both sides of the laminated coil approximately at the center in the thickness direction are shifted by 180 degrees. (7) The method for curing adhesive for a laminate coil according to claim 1 or 2, wherein the resistance heating is controlled based on the electrical resistance between the outer end and the inner end of the laminate coil. (8) A metal pipe, a metal sheet, or a pipe covered with a metal mesh is used as the winding core of the laminate coil, and the metal pipe, metal sheet, or metal mesh is heated by electric induction to form a portion near the inner peripheral surface. 3. A method for curing an adhesive for a laminate coil according to claim 1 or 2, wherein the adhesive is externally heated.