JPH0323434B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a food container equipped with a heating element, in which a heating element is provided in the container itself, and food inside the container is kept warm by heat radiation from the heating element.

BACKGROUND ART Conventionally, as a container for keeping lunch boxes and the like warm, containers such as thermos flasks are generally used, which are equipped with an insulating material to prevent the heat of cooked food from being radiated to the outside. In addition, in order to hand over-the-counter snack food to customers in a warm state, for example, it is necessary to heat it in a microwave oven or the like immediately before selling it, or to leave it in a heated refrigerator. It is taken.

However, with the above-mentioned containers that prevent heat from radiating to the outside with the insulating material, it is not possible to raise the temperature of the food stored inside the container to a higher temperature than when it was stored, and in order to maintain a large heat retention capacity, the container is bulky. , it is inconvenient to carry. In addition, in the case of snack foods, etc., due to the need to keep prices low, only disposable and inexpensive materials can be used for the containers, so the heat retention effect has to be extremely low.

Furthermore, methods of reheating in a microwave oven or storing in a heating cabinet have the disadvantage that they are not suitable for portability and require large equipment.

Furthermore, conventional heat retention methods keep cooked food warm in the container, which has the disadvantage that steam accumulates inside the container, and the smell of the container itself is transferred to the food, impairing its taste.

This invention was made in view of the above points, and includes providing a heating element in the container itself for storing food.
By supplying direct current or alternating current heating current to this heating element, the heat radiated from the heating element keeps the food stored in the container warm.It is convenient to carry, and even if it is sold in a store or in a stored form. To provide an inexpensive food container with a heating element that does not require special heating equipment. Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a partially cutaway oblique view of a food container with a heating element according to the present invention, and FIGS. 2 a to 2 d are exploded views for explaining the method of manufacturing the container shown in FIG. 1. In these figures, 1 is the front and rear plates of the container, 2 is the side plate of the container, and 3 is the bottom plate of the container. When the required parts are bent and assembled as described later, the container main body 4 shown in FIG. 1 is completed. Reference numeral 5 denotes a lid that is placed over the top opening of the container body 4. The container body 4 and the lid 5 are made of an electrically insulating material such as cardboard or synthetic resin paper.

Next, a method for manufacturing a food container with a heating element according to the present invention will be explained with reference to FIGS. 2a to 2d.

First, as shown in FIG. 2a, conductive metal foils 11 are pasted on both sides of a rectangular paper body 10. In this case, since the width of the conductive metal foil 11 is sufficiently large, it can be attached with extremely good workability. Next, as shown in FIG. 2b, the outer shape is punched out into a desired shape using a press. Thereby, the conductive metal foil 11 becomes the electrode 6. Thereafter, as shown in FIG. 2c, a conductive silk printing paste is applied onto the paper body 10 between the electrodes 6 on both sides using a silk printing method, and a heating element 7 is provided in the form of a strip. Next, as shown in FIG. 2d, the insulating layer 8 is formed by covering the portions other than those required as electrode terminals with insulating ink using a silk printing method. The portion of the electrode 6 that is not covered with the insulating layer 8 becomes the electrode terminal 6a.

Then, fold it inward along the dashed dotted line 9, and
By bending the outer pieces 1a of the front and rear plates 1 outward, the food container with heating element shown in FIG. 1 is obtained.

Examples of conductive silk printing paste include:
"Electrdag 423 TH" (trade name of Nippon Acheson Co., Ltd.) is used. Its specifications are as follows.

Properties Raw solution: Conductive particles Graphite binder PVC Color Black Viscosity (CPS) 50000-80000 Specific gravity Kg/ 1.13 Solids content 36% Flash point 76℃ Effective storage period 1 year (in original sealed state) Dry coating properties Covered area (m ² /Kg at 1mil): 11 Sheet resistance (Ω/sq at 1mil): 30-50 Heat resistant temperature: 104℃ Drying After printing, perform heat drying (65-82℃) for about 30 minutes.

When using the conductive silk printing paste as described above, the amount of heat generated is set by controlling the film thickness using a screen mesh.

Figure 3 shows the bottom plate 3, electrode 6, heating element 7, and insulating layer 8.
FIG. 3 is a cross-sectional view showing details of the laminated structure of FIG.

Next, the specifications of the food container with heating element having the above structure will be explained. When a power terminal is connected to the electrode terminal 6a and a heating current is passed through the heating element 7, the heating element 7 is heated and heat is radiated from its surface, warming the food contained in the container body 4. At this time, the total combined resistance of the heating element 7 is set to 30 Ω or less, and the power supply voltage is set to 30 volts or less in direct current or alternating current to cause the heating element 7 to generate heat at a low temperature, and the food stored in the container body 4 is
Try to keep it at 60-80℃.

Propagation of germs can be suppressed by supplying current from a simple-structured power source to the food container with a heating element constructed as above, and keeping the temperature of the food between 60°C and 80°C using a time switch, etc. With,
Hot food can be provided immediately upon customer request. Further, the power source for the warmer may be either direct current or alternating current, and in particular, if the power source from the battery of a car is used, food such as boxed lunches can always be kept warm in the tribe. Further, since the resistance value of the heating element 7 can be freely adjusted depending on the thickness and area of the conductive silk printing paste applied, the amount of heat generated by the heating element can also be adjusted thereby.

In the above embodiment, the heating element 7 is provided in the shape of a strip on the bottom plate 3, but the heating element 7 is not limited to the shape of a strip, and as shown in FIG. The structure may be formed by coating. Further, in the above embodiment, the electrode 6 and the heating element 7 are provided on the inner surface of the container, but the electrodes 6 and the heating element 7 are not limited to the inner surface of the container, but may be provided on the outer surface. Further, by changing the shape of the insulating layer 8 formed on the electrode 6, the electrode terminal 6a can be formed in any shape.

As explained in detail above, the food container with a heating element according to the present invention has two electrodes made of conductive metal foil provided on the outer or inner surface of a box-shaped container made of an electrically insulating material such as a synthetic resin material. A heating element is formed by directly applying a conductive silk printing paste between these two electrodes using a silk printing method, and then an insulating layer is formed by applying insulating ink over this heating element using a silk printing method. In addition, a part of the box-shaped container is bent and a conductive metal foil is placed on top of it as an electrode terminal, so that by supplying a small current to the heating element through the electrode terminal, heat is radiated from the heating element and the inside of the container is increased. The food stored in the can be kept warm at all times.

In addition, in this invention, conductive metal foil is pasted on a paper body at intervals to form electrodes, and a conductive silk printing paste is applied between these electrodes to form a heating element. Electrodes can be provided in both the horizontal and lateral directions, and electrode terminals are formed by bending a part of the box-shaped container outward, so the desired size can be placed on the required part of the outer surface of the box-shaped container. Electrode terminals can be provided with. Further, since the electrode terminal is formed by leaving a part of the conductive metal foil without insulation, it becomes strong. Moreover, since the electrode terminals are formed on the side surface of the food container, even if a large number of food containers are stacked, it is possible to easily conduct electricity to each one. Furthermore, since a conductive silk printing paste is applied between the electrode metal foils, some of which serve as electrode terminals, to form a heating element, the connection between the heating element and the electrodes is extremely reliable. Moreover, it is easy to apply not only to the container body but also to the lid. Furthermore, since the insulating layer is formed using insulating ink, the process is simpler and the cost can be reduced compared to the case where an insulating film is pasted.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a food container with a heating element according to an embodiment of the present invention, FIGS. 2 a to 2 d are exploded views for explaining the manufacturing process of the food container with a heating element shown in FIG. FIG. 3 is a sectional view showing the laminated state of the container bottom plate, electrode, heating element, and insulating layer, and FIG. 4 is a diagram showing the electrode and heating element of the container bottom plate in another embodiment. In the figure, 1 is the front and rear plates of the container, 2 is the side plate of the container, and 3
is the bottom plate of the container, 4 is the container body, 5 is the lid, 6 is the electrode, 7 is the heating element, 8 is the insulating layer, 10 is the paper body, 11
is a conductive metal foil.

Claims (1)

[Claims] 1 Two band-shaped electrodes made of conductive metal foil are provided facing and separated from each other on both sides of the outer or inner surface of a rectangular paper body made of an electrically insulating material, and a conductive silk printing paste is placed between these two electrodes. A heating element is formed by directly applying the heat generating element using a silk printing method, and insulating ink is applied using a silk printing method over the heating element and the conductive metal foil to form an insulating layer on areas other than those that will become electrode terminals. After the outer shape of the paper body is made into a predetermined shape, it is bent to form a box-shaped container, and the part that will become the electrode terminal is bent onto the side surface, and the conductive metal foil thereon is used as the electrode terminal. A food container with a heating element.