JPH11268777A - Electro-heating food-container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat-sterilize easily and surely by forming a container having, as its constituent elements, at least a pair of aluminum electrodes and an insulation member and forming a conductive ink layer, which comprises a resin composition containing conductive powder, onto at least part of a face where an aluminum electrode contacts contents. SOLUTION: In the case of application to a rolled-can type as an electro- heating food-container, a conductive ink layer containing Ti-Al intermetallic compound powder is formed on an aluminum plate, and such an aluminum plate is die-cut to obtain can lid materials 1. On the other hand, a cylindrical resin can body 2 is produced by injection molding, in the case of which a layer 3, comprising rubberlike elastic body, for rolling and sealing is placed in a flange part in advance. Then, a bottom part is formed at one end of the cylindrical resin can body 2 by rolling and molding the lid material 1 so that the conductive ink layer comes as a container's internal face, and the electro-heating food container is thus obtained. Then, after food is filled into the container, it is hermetically rolled and sealed with the other lid material 1 so that the conductive ink layer comes as a container's internal face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a food container for electric heating.

[0002]

2. Description of the Related Art Retort foods are manufactured by filling and sealing the contents of a container, and then heat sterilizing with steam or the like. Since completely sterilized foods can be easily provided, retort foods have become very popular in recent years.

[0003] In the conventional method of heating from the outside, there is a problem that since heat is transferred through the container wall, it takes a long time to raise the temperature, and the flavor is deteriorated or discolored due to overheating. In order to solve this problem, a “sterile filling and packaging system” for filling and sealing a pre-sterilized food and a container in a sterile environment has begun to spread mainly for beverages.

[0004] However, the heating of food in this method is due to heat exchange with a heating medium such as boiling water or steam.
For solid foods, high-viscosity foods, and the like, the rate of temperature rise cannot be increased sufficiently. This is the aseptic filling and packaging system
Is one of the reasons that the scope of application cannot be expanded to foods other than beverages.

[0005] In this regard, an energization heating method in which an alternating current is applied to foods to perform heat sterilization by utilizing self-heating (Joule heat) due to the inherent resistance of each food is disclosed in Japanese Patent Application Laid-Open No. H11-157,197. In the limelight as a means to dramatically increase speed, various foods such as kamaboko, frozen strawberry, large meat stew and the like are increasing in performance. The following techniques have been developed and proposed as the electric heating method.

(1) A method of packaging food is known in which after packaging a food material with a moisture-permeable packaging film body, an electrode plate is pressed from the outside of the packaging material to conduct electric heating (JP-A-63-207).
371).

However, according to this method, since the moisture-permeable packaging membrane is permeable to moisture, not only does the amount of moisture in the food during storage after heating become abnormal, but there is also a risk that bacteria may enter and propagate. In addition, if the packaged food with the moisture-permeable packaging membrane after heating is further packaged with the water-impermeable packaging membrane, it takes time and effort to package it in an aseptic state, so the simplicity required for the manufacture of retort foods Result.

(2) A sealed packaged food product in which an energizing plate having energizing projections for fastening is attached to both open ends of an insulating packaging bag filled with food material, and both open edges are fastened to the protrusions. (JP-A-55-89034, JP-A-63-207369).

However, in these techniques, since the current-carrying plate is covered with the wrapping film, stress concentrates on the wrapping film portion at the edge of the current-carrying plate, and there is a risk that pinholes are generated. . In particular, in a drop test generally performed on food packaging products, it is not easy to prevent the occurrence of breakage from the edge of the conductive plate. In addition, the sealing method is to cover the encapsulating energizing projection on the energizing plate on the side opposite to the content food with a packaging film, and further ligate it with a metal strip, string, or the like, but use ham, sausage, or the like. Unlike general ligation to the packaging membrane alone, the ligated part, which is the boundary between the current-carrying projections that cannot be deformed and the packaging membrane, is likely to have a microcommunication opening, which may allow bacteria to enter from this part. Will be higher.

[0010] Furthermore, in the above-mentioned technology, the cost tends to be too high for food packaging products in which disposables are the principle. Considering food filling using a packaging bag, sealing work, etc., take out the packaging bag from which the current-carrying plate was tied at one end in advance from the stock part, fix the opening on top, and then set
Fill the food quantitatively, then insert the current-carrying plate through the opening, fasten the open-end wrapping film to the current-carrying protrusion for fastening,
Furthermore, it is fastened and fixed with a ligating string from above. That is, in this technology, there are many complicated operations that require a high-performance robot. In particular, the operation of inserting an energizing plate into a packaging bag requires high three-dimensional accuracy, and requires equipment cost, operating speed (production cost), and the like. Increase is inevitable. In this respect, the above-mentioned technology is difficult to adapt to the current food filling and packaging system which achieves both safety reliability and high speed of the product by a high degree of automation.

(3) There is a method of attaching electrodes made of various shapes of titanium or titanium alloy to a container or a bag by screwing, welding, bonding, embedding welding, or the like.
No. 100172). Among the methods disclosed herein, a method of partially laminating a titanium foil is most suitable for mass production and is advantageous in cost.

However, in comparison with the current manufacturing method of packaging materials, it is necessary to produce a raw material by sticking a titanium foil on each sheet at a predetermined position. Aligning and laminating the titanium foil parts of the raw material requires a number of steps, and the titanium foil itself is very expensive, which makes it very expensive packaging material. Become. Also, even if it is foil, the titanium material itself is very hard, and when making a bag by bonding it to a resin film,
Since the flexibility and hardness are extremely different at the boundary between the portion where the titanium foil is not provided and the portion where the titanium foil is not provided, damages such as holes and cracks are likely to occur. Also, the foil edge breaks through the laminated film,
There is even a risk of injuring the user's hand, finger, etc. when opening.

(4) There is a method in which a high-frequency power supply is used for energizing heating, and after the energizing heating, resealing is performed inside the electrode material, thereby avoiding contact between the electrode and food and sealing (JP-A-6-178675). Gazette).

However, the method of manufacturing the package itself is the same as the above (3), and the number of steps is still large.
High costs are inevitable.

The resealing of the package inside the electrode material which has been used after the electric heating is performed because the package is sealed (heat fusion) in a state where the food is present inside. Adhesion becomes unstable due to the presence of food on the surface. In particular, if the solid food is heat-sealed while being bitten on the fusion surface, fine gaps are generated, which can be an effective route for bacteria to enter.

[0016] Poor heat fusion due to biting of solid foodstuff
The most popular "food filling and heat sealing packaging system"
Is also a very common accident type. Considering the circumstances in which various measures have been taken to countermeasures, it is not an exaggeration to say that the technology relating to re-fusing goes against the trend.

In this regard, a method called “filling seal” is known as a filling sealing method for noodle soup, jelly, tofu and the like. This is very similar to the re-fusion in that the liquid food on the fusion surface is sealed while eliminating the liquid food. In other words, there is a drawback that in order to avoid the invasion of bacteria, strict restrictions are imposed on the content food, packaging material (material, shape), shape of the thermocompression bonding element of the heat sealing device, heat sealing conditions, and the like.

(6) A carbon-based conductive powder such as carbon or graphite is mixed with a resin-based binder such as epoxy resin or polyester as an electrode material, and an ink-formed conductive material is coated on an electrode substrate such as titanium or aluminum and heated. Then, there is a method in which the electrode on which the conductive layer is formed is brought into contact with food and heated by energization (Japanese Patent Laid-Open No. 4-16168).

However, this conductive film or kneaded film must contain at least 10% by weight of carbon in order to obtain a practical level of conductivity. (FD
A) In some cases, the standards of the Polyolefin Hygiene Council cannot be met.

[0020]

As described above, the conventional energization heating method is still expensive and cannot be said to be sufficiently reliable in terms of safety and hygiene. On the other hand, the “sterile filling and packaging system” itself has high equipment costs, and technical problems still remain in handling large solids. For this reason, development of a system that can surely be heat-sterilized without impairing the simplicity required in the production of retort foods has been desired.

Accordingly, it is a main object of the present invention to provide a low-cost food container for electric heating which is excellent in safety and hygiene.

[0022]

Means for Solving the Problems In view of these problems of the prior art, the present inventors have conducted intensive studies and, as a result, have found that a container having a specific structure can achieve the above object, and finally complete the present invention. Reached.

That is, the present invention provides a container comprising at least a pair of aluminum electrodes and an insulating member, wherein the pair of aluminum electrodes face each other via an insulating member, and the aluminum electrode is formed on the contents. The present invention relates to a food container for electric heating in which a conductive ink layer made of a resin composition containing a conductive powder is formed on at least a part of a contacting surface.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION As a basic structure of a container of the present invention, at least a pair of aluminum electrodes and an insulating member are constituent elements, and a pair of aluminum electrodes face each other via an insulating member.

The material of the aluminum electrode may be either pure aluminum or an aluminum alloy.
Examples of aluminum alloys include Al-Mn alloys and A
l-Mg type, Al-Mg-Mn type and the like. JI
According to the S standard, aluminum alloys such as 3003, 3004, and 5082 can be used. Among these, in the present invention, it is particularly preferable to use pure aluminum.
The form of the electrode may be any of a plate shape, a foil shape and the like.
In addition, the thickness of the electrode can be appropriately set according to the use of the container and the like, but is usually set to 2 mm or less. For example, when the container of the present invention is disposable, it is particularly preferable that the thickness be 200 μm or less from the viewpoint of economy and flexibility.

In the present invention, a conductive ink layer made of a resin composition containing conductive powder (also referred to as conductive ink) is formed on at least a part of the surface where the aluminum electrode contacts the contents. That is, in the present invention, the conductive ink layer is formed on the aluminum electrode so as to contact the contents.

The type of the conductive powder is not particularly limited as long as it is basically conductive. For example, titanium, a titanium-based alloy or an intermetallic compound (such as a Ti-Al-based intermetallic compound), Titanium-based ceramics (TiN, T
iB ₂ , TiC, etc.), zirconium boride, nickel,
Silver or the like can be used. Further, a powder prepared by any production method can be used. One or more of these conductive powders can be used. Among these, powders such as titanium, a titanium-based alloy or an intermetallic compound are preferable, powders such as titanium and a Ti-Al intermetallic compound are more preferable, and titanium powder is most preferable.

The size and shape of the conductive powder are not particularly limited as long as the powder can be uniformly dispersed in the resin composition. In the present invention, the average particle size is about 0.2 to 100 μm (preferably 0.2 to 20 μm). It is preferable to use a granular or flaky powder having a degree (value measured by a laser diffraction type particle size distribution analyzer). If necessary, these may be used in combination. When flake-like powder is used, flake-like powder having an average thickness of 5 μm or less is preferable. These powders can be obtained by a known powder production method, a pulverization method, or a combination thereof, and a commercially available flake powder can be used as it is.

The content of the conductive powder can be appropriately changed depending on the kind of the conductive powder to be used and the like, but is usually about 10 to 80% by weight, preferably 30 to 80% by weight in the conductive ink layer. good.

As the resin component in the resin composition,
There is no particular limitation as long as the conductivity of the conductive ink layer can be ensured. For example, resins such as polyethylene (PE), polypropylene (PP), polyester, polyamide (nylon, etc.), epoxy resins, and the like are included. These can be used alone or in combination of two or more. In the present invention, a heat-fusible resin such as chlorinated polypropylene, carboxylated polypropylene, or polybutylene terephthalate can be used. In the present invention, the resin may be appropriately selected according to the type of the conductive powder used and the like.

In the resin composition, in addition to the conductive powder and the resin component, an organic solvent, a lubricant, a plasticizer, and the like may be contained as needed within a range not to impair the effects of the present invention. As the organic solvent, a known solvent can be used, and it may be appropriately determined according to the type of the resin component used. For example, methyl ethyl ketone (MEK), ethyl acetate, toluene and the like can be used. These solvents can be used alone or in combination of two or more.

The resin composition can be produced by a method similar to that of the known resin composition, by uniformly mixing the components using a known stirrer, mixer or the like. The obtained resin composition is applied as it is to an electrode (substrate) and dried by heating, or by pasting a pre-formed sheet into an aluminum electrode,
A conductive ink layer can be formed. In the case of sticking, heat bonding or a known adhesive or the like can be used. As the adhesive, a conductive adhesive is particularly preferable. Examples of the conductive adhesive include an epoxy resin adhesive in which a silver paste is dispersed, a urethane adhesive for dry lamination in which silver particles or a conductive carbon filler is dispersed, and the like. As the former commercial product, for example, "Zero Ohm" (trade name) (manufactured by Ougi Chemical Industry Co., Ltd.) can also be used.

The conductive ink layer is formed on at least a part of the surface where the aluminum electrode contacts the contents.
That is, the conductive ink layer may be formed on the entire surface or a part of the surface where the aluminum electrode forms the inner surface (inner wall) of the container. It is preferable to form a conductive ink layer on the entire surface of the aluminum electrode because corrosion of the aluminum electrode can be more reliably prevented regardless of the contents.

The color of the conductive ink layer may be black or gray depending on the conductive powder or the contents. In order to enhance the aesthetic appearance, for example, Japanese paper is used between the contents and the conductive ink layer. By interposing a water-absorbing or water-containing material such as that described above, the color (blackness) can be reduced.

On the other hand, the other side (back side) of the aluminum electrode
Is intact (ie, exposed to the outside)
However, if necessary, a treatment for imparting corrosion resistance or the like may be performed. As a treatment method, there are a method of forming an insulating material layer, a method of forming a conductive layer, and the like. As the former, an insulating material layer such as an epoxy-based corrosion-resistant coat or a heat-resistant polyethylene terephthalate film can be formed. In the latter case, a conductive filler (for example, a conductive powder such as carbon, titanium, titanium aluminum, nickel, tin, copper, or silver) is contained in an epoxy-based corrosion-resistant coat, a heat-resistant polyethylene terephthalate film, or the like. A conductive film layer or a conductive coating layer can be provided.

The location of the aluminum electrode (electrode portion) is not particularly limited as long as the pair of electrodes is separated by an insulating member, and may be appropriately determined according to the type of the container. For example, in the case of a canned can type, the bottom part and the lid part of the can can be used as the electrode part. In the case of the gusset packaging type, each folded side of the gusset bag can be used as an electrode portion. In this case, if the power supply metal needle is pierced into the heat-sealed portion in the electrode portion, the electrode portion comes into contact with the metal needle and power can be supplied (for example, see Example 4 described later).

The aluminum electrode is in any state (positional relation, distance, etc.) as long as the contents can be heated by energization.
May be opposed. For example, the pair of aluminum electrode surfaces may or may not be in a parallel state. Further, the form of the facing aluminum electrode surface is not necessarily required to be flat, and may be any form such as a curved surface or a wavy surface. The shape of the entire aluminum electrode may be appropriately set according to the shape of the container and the like.

The kind of the insulating member is not particularly limited, and a material used as a known food container or packaging material can be used as it is. Examples thereof include resins such as polyethylene (PE), polypropylene (PP), polyester, polyamide (nylon, etc.), and epoxy resins, as well as paper and paperboard, glass, wood materials, ceramics, and composite materials thereof. . These are 2
It can also be used as a laminate of more than one kind. In the present invention, heat-fusible resins such as chlorinated polypropylene, carboxylated polypropylene, polyethylene, and polybutylene terephthalate can be used. In particular, when a heat-fusible resin is used for at least one of the insulating member and the resin component, this functions as a heat sealant,
The components of the container can be joined to each other by heat fusion (heat sealing), and the container can be easily manufactured.

The present invention can be applied to any of known containers and packaging forms, regardless of the type. For example, a box, bottle, can, other molded container using a rigid packaging material, or a gusset type, a pillow type, a stick type, a strip type, etc. using a flexible packaging material can be applied. Therefore, the basic configuration of the container of the present invention can adopt the basic configuration of each of these containers as it is.

The method for producing a container according to the present invention is also basically
These conventional container manufacturing methods can be applied.
For example, it may be manufactured integrally by injection molding, extrusion molding, or the like, or may be manufactured by joining each component by a known adhesive, heat fusion, or the like. However, in the present invention, even when the heat-fusible resin is not used for any of the insulating member and the resin component, the heat-fusible resin is applied to both or any of the portions where the components of the container are joined. The provision of the resin layer facilitates the production of the container by heat fusion. In the case where heat fusion is not used, the components may be integrally formed as in a known container, or each component may be joined with an adhesive (particularly, a conductive adhesive or the like is preferable). It should be noted that a known heat fusion apparatus can be used as it is for each heat fusion (heat seal) in the present invention.

Further, a rubber-like elastic layer may be interposed at the joint between the aluminum electrode and the insulating member, and if necessary, the aluminum electrode and the insulating member may be formed by caulking. Thereby, more excellent sealing performance and the like can be secured. As the rubber-like elastic body, known ones can be used, for example, urethane elastomer, silicone rubber, various other natural and synthetic rubbers and the like can be used. In this case, if the joining portion is a convex flange portion, the power supply jig can be easily and reliably press-contacted, and power can be supplied smoothly.

Further, if the flange portion is designed so as to form an ear-shaped tab after the flange portion is wound and formed, power can be easily supplied as a power supply electrode piece (for example, see Example 2 described later). ). On the other hand, as described above, by providing a conductive film layer or a conductive coating layer on the other surface (the surface exposed to the outside) of the aluminum electrode, the ear-shaped tab can be particularly formed while maintaining the corrosion resistance and the like of the aluminum electrode. Even without the provision, power can be supplied to almost the entire surface of the aluminum electrode.

The type and form of contents (food) applicable to the container of the present invention are not limited as long as they have conductivity. For example, it can be applied to any kind of fish and shellfish, animal meat, vegetables, fruits, dairy products and the like. Furthermore, it may be any of liquid, solid, paste, gel, etc., and it does not matter whether it is a product (cooked product), a semi-processed product, a raw material, or the like. For example, kneaded products (ham, sausage, kamaboko, bamboo, bamboo, etc.), cooked products (curry, stew, soup, boiled food,
Hamburger, shrimp, etc.), boiled noodles, confectionery, seasonings, beverages, soup stocks and soups. In addition, the container of the present invention can be used for boiling foods or thawing frozen foods.

The method of heating by heating using the container of the present invention itself can basically be applied to the method of heating by heating in the conventional heated food. For example, by using a known power supply jig, the power supply portion is brought into contact with the aluminum electrode of the container of the present invention, and heat sterilization can be performed by applying an alternating current of 20 to 200 V at 50 to 50,000 Hz.
In this case, if the power supply portion is pressed against the aluminum electrode by providing a convex flange portion, power can be supplied easily and reliably (for example, see Example 1 described later).

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments will be described with reference to the drawings to further clarify the features of the food container for electric heating according to the present invention.

Example 1 Winding can type First, a 0.2 mm thick aluminum plate was coated with a conductive ink containing a powder of a Ti-Al-based intermetallic compound.
Baking to form a conductive ink layer having a thickness of 10 μm.
An epoxy-based conductive coating layer is formed on the other surface of the aluminum plate. The aluminum plate coated on both sides in this way is punched into a disk shape to obtain can lids (1) and (1) shown in FIG.

On the other hand, as shown in FIG. 2, a cylindrical resin can body (2) having both ends flanged for winding is produced by injection molding. A layer (3) made of a rubber-like elastic material for a sealing seal may be interposed in advance in the flange portion.

At the one end of the cylindrical resin can body, the above-mentioned lid material is wound and formed so that the conductive ink layer is located on the inner surface of the container, thereby forming a bottom portion. Next, after filling the container with the food, the container is sealed with a lid so that the conductive ink layer is on the inner surface of the container. Depending on the contents, preserving and storing for a longer period of time is possible by reducing the pressure or vacuum in the container before sealing and then sealing. In each of the steps of manufacturing the lid material, manufacturing the resin can body, manufacturing the energized resin can container, and filling and winding the food, all of the conventional mass production lines can be applied as they are. Also, a conventional pull-top open lid system can be adopted as the lid material.

Next, as shown in FIG. 3, the container is placed on a power supply base of a power supply system such that a lid (1) serving as an electrode portion is vertical. Electric current is supplied from the power supply plates (5) and (5) that come into contact with the flange portions (4) while pressing the can lid surface side, and the content food is electrically heated. When a non-conductive corrosion-resistant coating layer is laminated on the outer surface of the aluminum electrode, a peeling vibrator is pressed in advance on a part of the peripheral part of the cover material tightening convex as a power supply terminal, and the anti-corrosion film is scraped off. A part may be formed.

In order to heat the contents to 100 ° C. or higher, the container is placed in a pressure cooker similar to a retort cooker while the container is housed in a power supply stand, and is heated by applying electric current under pressure, and is maintained at the reached temperature for a predetermined time. The content may be cooled to below the filling temperature by water cooling under pressure. The operation other than the heating method may be the same as the operation procedure in a normal retort pot. In addition, at the time of heating, the power supply gantry can be shaken and shaken with the container accommodated as necessary, so that the contents can be heated uniformly. The ink coat on both sides of the lid material in the container of the present invention has excellent adhesion and film strength, and does not cause damage such as peeling even when the resin can body is tightened.

Example 2 Container Lid Heat Seal Type A resin cylindrical body having heat seal flanges provided at both ends is manufactured by injection molding. On the other hand, thickness 3
Ti-Al on one side of 0-60 μm aluminum foil
After applying the resin composition containing the base intermetallic compound powder, it is baked to form a conductive ink layer of 5 to 7 μm. The other surface of the aluminum foil may be provided with the same anticorrosive resin coat as in Example 1, or a resin film such as polyethylene terephthalate (PET) may be attached.

As shown in FIG. 4, the aluminum foil was used as a lid material (8), and this was continuously heat-sealed to the flange portion (7) of the tubular body (6), and the bottom portion was an electrode portion. A container is prepared. The aluminum foil is formed such that the conductive ink layer forms the inner surface of the container. In this case, the heat sealing agent used for heat fusion may be, for example, preliminarily transferred to both flange portions (7) and (7) of the cylindrical body, or may be a conductive material in the lid material portion in contact with the flange portions. May be overcoated on the hydrophilic ink layer.

As the resin component in the conductive ink layer,
For example, when a heat-fusible resin such as chlorinated polypropylene and carboxylated polypropylene is used, it is not always necessary to coat the tubular container with the heat-fusible resin. When a conductive heat-fusible (thermoplastic) film containing a conductive powder is bonded to aluminum, the coat of the heat-fusible resin may be omitted.

After the contents are continuously filled in the container while being continuously supplied by a stocker, a separately prepared lid material is continuously connected to the flange portion (7) such that the conductive ink layer is on the inner surface of the container. And is punched into a predetermined shape to form a lid material.

In the case where a non-conductive corrosion-resistant coating layer is laminated on the outer surface of the aluminum electrode, particularly, as the power supply terminals of both electrodes, as shown in FIG. Ear-shaped tabs (9) and (9) are formed on each flange portion, and can be used as power supply terminals. A schematic diagram of a cross section of the tab is shown in FIG. The tab (9) can be formed by using the aluminum electrode (10) as it is, as shown in FIG. The method of piercing and fixing the tab with the needle-shaped feeding crimp terminal and feeding power is a low-cost and reliable method. Alternatively, a non-resin-coated conductive portion may be provided on the tab by masking, etching, or the like, to provide a power supply terminal.

After the contents are filled, as in FIG. 3, a large number of aluminum electrodes are housed in a power supply stand so as to be vertical, and the electrodes are heated by a power supply terminal. When trying to heat sterilize at a temperature of 100 ° C or higher, the contents are housed in a pressure cooker while housed in a power supply stand, and after being pressurized, heated and energized,
Remove from the kettle after cooling. This is the same as in the first embodiment.

In this case, depending on the contents, the upper part of the container may become hotter than the lower part due to convection. in this case,
The heated electric resistance of the upper portion is lower than that of the lower portion, and a larger current flows, so that the temperature of the upper portion is further increased. As a result, uneven heating may occur. In order to prevent such a phenomenon, the electrode portion of the lid may be vertically divided into an upper electrode A and a lower electrode B as shown in FIG. Then, by applying the current to the lower electrode B preferentially, overheating of the upper portion can be avoided, the temperature difference between the upper and lower portions can be reduced, and the content can be uniformly heated. In this case, as shown in FIG. 22, upper and lower pairs of electrodes (31) and (31) are respectively provided with insulating material layers (32) and (3).
What is necessary is just to laminate | stack through 2).

Example 3 Pillow packaging type (pillow container) One side of an aluminum foil having a thickness of 15 to 30 μm
A conductive ink containing i-Al intermetallic compound powder is gravure coated, dried and baked to form an electrode film. In this case, if the resin component of the ink is prepared based on a heat-fusible resin such as chlorinated polypropylene and carboxylated polypropylene, a heat-fusible conductive ink layer can be formed, and the production of packaging materials, filling seals, etc. The post-process becomes easy. The same effect can be obtained by dispersing a Ti-Al-based intermetallic compound powder in polypropylene or the like and using an electrode film in which a conductive film previously formed into a film is bonded to an aluminum foil by heat fusion or a conductive adhesive. can get. The other surface of the aluminum foil may be provided with a corrosion-resistant resin coat or a heat-resistant PET film or the like.

Separately, cast (unstretched) polypropylene (CPP) is used for the inner surface, polyethylene terephthalate or the like is used for the outer surface, and a long insulating film is prepared by bonding these heat-resistant insulating materials.

Next, as shown in FIG. 7, two coils are prepared for each of the electrode film (11) and the insulating film (12), each heat-sealing surface is on the inside, and the electrode film and the insulating film are always adjacent to each other. As described above, and a long rectangular cylinder is continuously produced. In the case of a gusset container, it is preferable to prepare a raw material coil in advance so that the width of the insulating film is wider than the width of the electrode film, whereas in the case of a pillow container, it is not always necessary to do so. FIG. 7 shows a state (cross section) in which each film is heat-sealed and folded.

The heat sealing step can be performed by a food filling and sealing machine similar to the conventional pillow packaging type. Transverse heat sealing is performed in such a manner that the center line of the opposing electrode film is bent outward at the lower end of the continuously formed four-sided seal elongated cylinder to form the bottom of the elongated cylinder. Next, a certain amount of contents is filled from a nozzle inserted into the upper opening of the long cylindrical body. In this case, the center line of the electrode film is bent out at the upper cylindrical portion from the food filling portion and heat sealing is performed several times, and sealing of the filled bag and production of the bottom portion of the unfilled bag are continuously performed. Can be.

If the continuous filled and sealed long cylinder is cut off at a plurality of seal portions, the same packaged food as the conventional pillow package type can be easily and continuously produced. However, in the transverse heat sealing, since the vertical sealing portion (13) between the electrode film and the insulating film overlaps, it is necessary to seal the same portion a plurality of times in the same manner as the sealing of the gusset bag. If the vertical seals are still too tight and normal sealing is difficult,
As shown in FIG. 8, the outer fold line of the electrode film is slightly shifted from the center, and the vertical sealing portion (13) is used during transverse heat sealing.
What is necessary is to avoid overlapping. In addition, FIG.
Heat-sealed and folded state of each film (cross section)
It shows.

Each cylindrical bag filled with the contents is shown in FIG.
The electrode films are shaped so as to face each other in the steps shown in FIGS. After the shaping, as shown in FIG. 10 (a), it is housed in a power supply base, and a needle-shaped power supply crimp terminal (16) (also simply referred to as a power supply terminal) is pierced into the seal power receiving section (14) to complete the power supply preparation. . In the case of conducting heating at a temperature of 100 ° C. or more, the treatment may be performed in a high-pressure kettle while the container is housed in the power supply stand as in the first embodiment. FIG. 10B shows a state where the power supply terminal is pierced. The power supply terminal is fixed by a gantry fixed power supply bar (17). The power receiving terminal of the seal part is a female terminal (18) and a male terminal (19) of the power supply terminal.
And is energized through the terminal cord fastening bolt and nut (20).

When manufacturing the above rectangular long cylinder,
As shown in FIGS. 23 and 24, if heat sealing is performed in such a manner that a part of the tip of the conductive ink layer protrudes from the long cylindrical body (that is, the conductive ink layer is partially exposed after the heat sealing). Then, the power supply clamp (3) as shown in FIG.
4) Since (for example, a spring crimping method can be adopted) can be directly pressed and fixed, it is not necessary to pierce the power supply terminal into the container.

During energization, the triangular fold (15) in FIG.
Is folded to the bottom surface side and strongly adhered to the bottom surface, so that the temperature of the contents can be transferred even when a small amount enters the triangular folded portion. Further, an auxiliary heat source may be provided at the gantry contact portion to assist in raising the temperature.

Example 4 Gazette packaging type (Gazette container) The structure is the same as that of the pillow packaging type. However, as shown in FIG. 11, the point that the center line of the electrode film is folded into the bag in the bottoming sealing method is the pillow packaging type. The opposite is true.
In this case, if the seal at the corner is formed in a triangular shape (21), food cannot enter the corner, so that there is no concern that a region of insufficient heating and sterilization will occur at the time of energization, and the power supply terminal can be easily attached. Further, when producing a rectangular long cylindrical body as in the case of the pillow wrapping type, if heat sealing is performed so that the conductive ink layer partially protrudes from the long cylindrical body as shown in FIGS. Fig. 25
Since the power supply clamp as shown in can be pressed and fixed directly,
There is no need to pierce with the power supply terminal.

After the food is filled, the upper part of the food filling part is hermetically sealed with a gusset seal. Subsequently, a bottomed gusset seal is performed on the adjacent upper portion of the seal portion, and the food is fixedly filled with the nozzle. The difference between a bottomed gusset seal and a sealed gusset seal is the only difference in the direction of the triangular seal at the four corners. These gusset seals are used in the production of back gusset bags.

After filling and sealing the food, the filled bag is cut off, shaped, a power supply terminal is attached, and stored in a power supply stand.
The operation may be performed in the same manner as in Example 1 or the like until the product is taken out after heating and cooling in the pressure cooker.

Example 5 Resin Container Type A resin-made (for example, PET, polystyrene, polyethylene, polypropylene, etc.) window-formed cup container having a heat seal flange provided at an opening is prepared by injection molding. FIG. 26 shows a side view of the container. Window (3
5) is an electrode part, so at least two places are required on the side wall. However, in the present embodiment, the windows are two symmetrically positioned with respect to the center axis of the container. Such a cup container with a window can also be manufactured by processing a conventional cup-shaped container.

On the other hand, an electrode member was manufactured in the same manner as in Example 1. That is, a conductive ink containing a powder of a Ti-Al-based intermetallic compound is applied to one surface of an aluminum foil having a thickness of 100 µm, and then baked to form a conductive ink layer having a thickness of about 15 µm. On the other surface of the aluminum foil, a conductive coating layer having a thickness of about 20 μm is formed. The electrode member was cut out larger than the window, and the periphery of the window was heat-sealed so as to close the window (two places) by heat sealing so that the conductive ink layer was on the inside of the container. FIG. 27 shows a side view and a cross-sectional view of the container after the electrode member (36) is thermally fused.

After filling the contents and sealing with a heat seal lid material, the power supply terminals are brought into contact with the conductive coating layer located on the outside of the side wall of the container, and the contents are heated by energizing. As in the case of the first embodiment, when heating to 100 ° C. or higher, if the electric heating is performed under pressure in a retort pot, it is possible to prevent the container from being damaged or the contents from flowing out.

According to this method, it is possible to directly heat the food such as chawanmushi, pudding, etc., even if an air layer (nitrogen gas or the like) exists in the upper part of the container, even if the food solidifies during heating. Therefore, it is not necessary to incline the container at 90 degrees as in the first embodiment, and it is possible to prevent the contents from directly contacting the lid. Further, according to this method, a conventional resin container can be used almost as it is.

Test Example 1 (Pillow Container) Granular titanium powder (average particle size: 3 μm) wet-ground by an atomizing method and a ball mill and an epoxy resin were mixed at a weight ratio of 40/60, and an organic solvent (MEK / toluene /
Ethyl acetate = 1/1/1 (weight ratio))
The mixture was kneaded and dispersed with a main kneading roll for 30 minutes to prepare a paste-like conductive ink.

The above ink was diluted 3 to 4 times with the above organic solvent, applied on an aluminum foil with a bar coater,
Hot air drying (230 ° C. × 30 seconds) was performed to form a conductive ink layer having a thickness of about 6 μm, thereby preparing a conductive ink coated foil.

Masking a range of 180 mm × 100 mm on the conductive ink layer of the conductive ink-coated foil,
After applying a heat-sealing agent in which carboxylated polypropylene is dispersed, 180 ° C. × 3 in a hot air drier.
Dry baking was performed under the condition of 0 second. The film thickness of the obtained heat sealant was about 5 μm. As shown in FIG. 12, the heat sealant was cut so as to have a coat width of 10 mm, and the masking at the center was peeled off to obtain an electrode member.

On the other hand, as shown in FIG. 13, [50 μm CPP / dry adhesive / 20 μm
mPET] 200 mm x 100 m
m to obtain an insulating member. Next, the coated part of the heat sealing agent of the electrode member and the CPP film surface of the insulating member were overlapped with each other with a width of 7 to 8 mm and heat-sealed to produce a square cylinder having an inner size of 105 mm x 85 mm x 200 mm shown in Fig. 14. Further, as shown in FIG. 15, the center (22) and (22) of the electrode member are bent outward to form a bottom 10 m.
After heat sealing m, the bottom triangular portion of the electrode member was folded inward as shown in FIG. 9 to form a square container. In this square container, the electrode members and the insulating members face each other.

The rectangular container was replaced with a rigid container made of polycarbonate (1).
10mm x 110mm x 110mm)
Put 500g of meat-containing vegetable soup in a square container (filled up to a liquid level of about 50mm) and set as shown in Fig. 16 to 20k
Heating was carried out at a frequency of 100 Hz. As shown in FIG. 17, the power supply method is such that a power supply terminal composed of a combination of a female terminal (a) and a male terminal (b) is clamped and fixed on the upper portion of the heat seal portion of the opposing electrode member, thereby providing a titanium needle for supplying power. To make contact with the 50 μm aluminum foil in the heat seal portion. As a result, a current of 5 to 10 A could be supplied stably. FIG. 17A is a front view and a side view of a female terminal, and FIG. 17B is a side view, a front view, and a rear view of a male terminal. The power supply terminals include a female terminal (a) and a male terminal (b), and are provided with insulating resin covers (23) and (24), respectively. The female terminal secures the titanium needle with the fitting hole (25) and ensures contact with the aluminum foil.
It plays a role in preventing the titanium needle from falling off during power supply. The male terminal is provided with a titanium needle (26) and a terminal cord fastening bolt / nut (27).

After about 4 minutes of energization, the content food boiled, and after boiling for another 1 minute, the inside of the pillow container was examined. On the inner surface of the container, the conductive ink layer portion in which the soup was immersed was only slightly discolored, and did not peel off even in a cellophane tape peeling test, and there was no practical problem. In the cellophane tape peeling test, after cleaning and drying the inner surface of the container, the surface state of the cellophane tape (trade name) after adhesion and peeling was visually observed.

Test Example 2 (Gazette Vessel) Ti-Al intermetallic compound (T
i: Al = 50: 50 (at% ratio)) was wet-pulverized with an attritor to obtain an average particle size of 1 to 2 μm and an average thickness of 0.5 μm.
m were obtained. This was blended with the epoxy resin in a weight ratio of 30/70, and kneaded and dispersed with a three-kneading roll for 40 minutes to prepare a paste-like conductive ink.

The above-mentioned ink was mixed with the same organic solvent as in Test Example 1 for 4 hours.
６6 times diluted, coated on aluminum foil with a bar coater, dried with hot air (230 ° C. × 30 seconds),
A μm conductive ink layer was formed. Thereafter, an electrode member was manufactured in the same manner as in Test Example 1. On the other hand, the insulating member was manufactured in the same manner as in Test Example 1. The size of the insulating member is 200 mm × 170 mm, and its width is expanded by 70 mm. The electrode member and the insulating member were heat-sealed in the same manner as in Test Example 1 to produce a rectangular tube.

As shown in FIG. 18, the center (28) (28) of the opposing electrode member was folded inward, and the bottom portion 10 mm was heat-sealed to obtain an expanded and shaped gusset square container shown in FIG. Then, 1160mm × 110mm × 100
After the gusset container was placed in an acrylic container having a thickness of 5 mm, about 500 g of beef curry (filled up to a liquid level of about 30 mm) was placed in the container and heated in the same manner as in Test Example 1. The current value was 3 to 7 A because the distance between the electrodes was longer and the liquid level was lower than in the case of Test Example 1.

The temperature reached 100 ° C. in about 6 minutes after the heating, and after boiling for 1 minute, the inner surface of the container was observed. On the inner surface of the container, only the discolored portion of the curry immersion part was slightly discolored, and peeling of the conductive ink layer and the like was not recognized in the cellophane tape peeling test similar to Test Example 1.

In the caseet container, FIGS. 19 and 2
As shown in FIG. 0, if there is a portion where the inner surface of the electrode member is exposed in a triangular shape at the bottom and the distance between the electrodes (29) (29) is close, a large current flows to the bottom and the overheating is partially caused. There is. Therefore, if the coating area (30) of the heat sealing agent of the electrode member corresponding to FIG. 12 is enlarged as shown in FIG. 21, it is possible to avoid the possibility that the electrodes may contact at the bottom or cause uneven heating. it can.

[0084]

According to the food container for electric heating of the present invention, since the conductive ink layer is formed particularly on the aluminum electrode, 1) the aluminum electrode can be easily integrated into the container, 2). Even if a large current flows during energization, it does not break down due to heat generation. 3) Corrosion of the aluminum electrode over time can be prevented.

Therefore, heat sterilization can be performed easily and surely while maintaining a high sealed state, and high reliability can be exhibited in terms of safety and hygiene. Further, even after heat sterilization, it is possible to stably store the same for a long period of time.

In addition, by employing the conductive ink layer and the aluminum electrode, a flexible container having excellent conductivity and safety can be provided. Therefore, in manufacturing the container, a conventional container / packaging system is basically used as it is. As a result, it is possible to satisfy the simplicity required for the manufacture of retort food, and to provide a low-cost and highly reliable container.

[Brief description of the drawings]

FIG. 1 is a schematic view of a can container produced in Example 1.

FIG. 2 is a view showing a flange portion of a can container before being wound.

FIG. 3 is a cross-sectional view showing a state where a can container is installed on a power supply base of the power supply system.

FIG. 4 is a sectional view showing a state of a container with a conductive bottom in the container of Example 2.

FIG. 5 (a) is a view showing a container having an ear tab formed on a flange portion. FIG. 5B shows the XY of FIG.
It is sectional drawing which shows the flange part of a cross section.

FIG. 6 is a view showing a state in which an aluminum electrode serving as a lid material is wound so as to form an ear tab.

FIG. 7 is a cross-sectional view of a sealing portion showing a state in which an electrode film and an insulating film are transversely heat-sealed in Example 3.

FIG. 8 is a cross-sectional view of a sealing portion showing a state in which an electrode film and an insulating film are transversely heat-sealed in Example 3.

9 (a) to 9 (c) are process diagrams for manufacturing a pillow container in Example 3. FIG.

FIG. 10A is a diagram illustrating a state in which the pillow container according to the third embodiment is housed in a power supply base. FIG. 10B is an enlarged view of a joint portion of the needle-shaped power feeding crimp terminal in FIG.

FIG. 11 is a view showing a seal portion of the gusset bag.

FIG. 12 is a plan view of an electrode member used in Test Example 1.

FIGS. 13A and 13B are a plan view and a cross-sectional view of an insulating member used in Test Example 1. FIGS.

FIG. 14 is a view showing a prismatic tube obtained by heat sealing an electrode member and an insulating member.

FIG. 15 is a view showing a state where both electrode member surfaces of the rectangular tube are bent out.

FIG. 16 is a view showing a state in which power can be supplied from the power supply system to the shaped rectangular container.

FIG. 17 is a view showing the configuration of a needle-shaped feeding crimp terminal.
(A) is the front view and side view of a female terminal, (b) shows the side view, front view, and rear view of a male terminal.

FIG. 18 is a diagram showing a state where an electrode member is folded inward in the production of the gusset bag of Test Example 2.

FIG. 19 is a perspective view of a gusset square container of Test Example 2.

20 is a diagram showing a state in which the distance between the electrodes is short at the bottom of the gusset bag (a state in which the bottom of FIG. 19 is viewed from the container opening (directly above)).

FIG. 21 is a view showing a state where a coating area of a heat sealant is widened in the electrode member of Test Example 1.

FIG. 22 shows an upper electrode A and a lower electrode B as electrode portions of a lid member.
3A and 3B are a plan view and a cross-sectional view showing a state in which the upper and lower parts are divided vertically.

FIG. 23 is a cross-sectional view showing a state in which heat sealing is performed with a part of the conductive ink layer protruding from the long cylindrical body.

FIG. 24 is a view showing the appearance of a container which has been heat-sealed such that a part of the conductive ink layer protrudes from the long cylindrical body.

FIG. 25 is a schematic diagram of a power supply unit in a case where power is supplied using a heat-sealed container such that a part of a conductive ink layer protrudes from a long cylindrical body.

FIG. 26 is a side view of the cup container with a window according to the fifth embodiment.

FIG. 27 is a side view and a sectional view of a cup container with a window in which an electrode member is heat-sealed.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeo Sugita 3-6-8 Kutaro-cho, Chuo-ku, Osaka City, Osaka Prefecture Inside Toyo Aluminum Co., Ltd. (72) Inventor Kiyoshi Kondo 2-5-Nishi-Nagasu-cho, Amagasaki City, Hyogo Prefecture No. 30 Ogi Chemical Industry Co., Ltd.

Claims (6)

[Claims] 1. A container comprising at least a pair of aluminum electrodes and an insulating member as components, wherein a pair of aluminum electrodes face each other via an insulating member and a surface of the aluminum electrode in contact with the contents. A food container for electrical heating in which a conductive ink layer made of a resin composition containing a conductive powder is formed at least partially. 2. The conductive powder has an average particle size of 0.2 to 100 μm.
The food container for electric heating according to claim 1, wherein m is m. 3. The method according to claim 1, wherein the conductive powder is contained in an amount of 10 to 8 in the conductive ink layer.
The food container for electric heating according to claim 1, which contains 0% by weight. 4. The conductive powder comprises titanium powder and Ti-Al
2. The food container for electric heating according to claim 1, wherein the food container is at least one kind of a powder of an intermetallic compound. 5. The food container for electric heating according to claim 1, wherein the resin component in the resin composition is a heat-fusible resin. 6. The electric heating food container according to claim 1, wherein at least a part of the insulating member is a heat-fusible resin.