Jig for microwave oven heating

Abstract

To provide a technique capable of suppressing the occurrence of a defect derived from metal when heating an article stored in a metal can container in a microwave oven.SOLUTION: A non-metallic jig 10A for use in a microwave oven is used to install a metallic can 21 in the microwave oven with the metallic can 21 spaced apart from the W1 of the bottom of the microwave oven when an article 22 stored in the metallic can 21 is heated in the microwave oven. The container includes a support part 11 having a cylindrical shape and a flat reinforcing part 12 connected to one opening of the support part 11, and the support part 11 is configured to be fitted to both of a first canned product end part and a second canned product end part which are different from each other in at least one of shape and dimension.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a microwave oven heating jig. [Background technology]

[0002] Microwave ovens are a well-known method for heating packaged foods, and are widely used due to their simplicity.

[0003] However, when a container contains a metal layer and is heated in a microwave oven, the movement of free electrons in the metal layer is activated by the microwaves, which can cause discharge (sparks) between the metal layer and the grounded wall surface inside the microwave oven.Patent Document 1 describes a method of preventing this spark from occurring, in which a container body made of a composite sheet containing a resin sheet and metal foil formed into a cup shape is placed in a paper box and heated in a microwave oven.

[0004] Metal cans have the advantage of being more suitable for long-term storage of contents than plastic containers, and are stronger and therefore less likely to break, making them popular as containers for various types of canned food.

[0005] Furthermore, some metal cans can be opened almost entirely without using special tools. Food stored in such metal cans can be eaten as is without transferring it to another container. In this case, the food can be eaten at room temperature or after heating it in a hot water bath or the like. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2017-95163 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a technology that can prevent problems caused by metal when an item stored in a metal can container is heated in a microwave oven. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided a non-metallic microwave heating jig used to install a metal can container in a microwave oven at a greater distance from the bottom of the oven when heating an item contained in the metal can container in a microwave oven, the microwave heating jig including a cylindrical support portion and a flat reinforcing portion connected to one opening of the support portion, the support portion being configured to fit into both a first canned product end portion and a second canned product end portion which differ from each other in at least one of their shapes and dimensions.

[0009] According to another aspect of the present invention, there is provided a microwave heating jig according to the above aspect, wherein each of the first canned product end and the second canned product end includes a large diameter portion, and the support portion includes a first fitting portion that fits with the large diameter portion of the first canned product end and a second fitting portion that fits with the large diameter portion of the second canned product end.

[0010] According to yet another aspect of the present invention, a dielectric constant at 2.45 GHz is 5 or less and a dielectric loss tangent at 2.45 GHz is 7.0 × 10 -3 There is provided a microwave oven heating tool according to any one of the above aspects, which is made of the following material.

[0011] According to yet another aspect of the present invention, there is provided the microwave oven heating jig according to the above aspect, wherein the material is a cured resin.

[0012] According to yet another aspect of the present invention, there is provided a canned product with a jig, comprising the metal can container and the item contained therein, and a microwave heating jig according to any of the above aspects.

[0013] According to yet another aspect of the present invention, there is provided a jig-attached canned product according to the above aspect, in which the canned product has its upper end as one of the first canned product end and the second canned product end, and its lower end as the other of the first canned product end and the second canned product end.

[0014] According to yet another aspect of the present invention, there is provided a kit for canned products with a jig, comprising the microwave heating jig according to any one of the above aspects and the metal can container.

[0015] According to yet another aspect of the present invention, there is provided a kit for canned products with a jig according to the above aspect, in which the canned product including the metal can container and the item contained therein has an upper end portion as one of the first canned product end portion and the second canned product end portion, and a lower end portion as the other of the first canned product end portion and the second canned product end portion. [Effects of the Invention]

[0016] The present invention provides a technology that can prevent problems caused by metal when an item stored in a metal can container is heated in a microwave oven. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view of a microwave heating jig according to one embodiment of the present invention. [Figure 2] 2 is another perspective view of the microwave heating jig shown in FIG. 1. FIG. [Figure 3] 3 is a cross-sectional view taken along line III-III of the microwave heating jig shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view of a canned food product with a jig attached, including the microwave oven heating jig shown in FIGS. [Figure 5] FIG. 5 is a cross-sectional view showing the jig-attached canned product shown in FIG. 4 in which the attachment position of the microwave oven heating jig has been changed. [Figure 6]FIG. 6 is a perspective view showing an example of a microwave oven in which the microwave oven heating jig shown in FIGS. 1 to 3 can be used. [Figure 7] FIG. 7 is a cross-sectional view showing the state in which an open canned product is placed on the bottom surface of the microwave oven via the microwave oven heating jig shown in FIGS. [Figure 8] FIG. 8 is a perspective view of a microwave heating jig according to a modified example. [Figure 9] FIG. 9 is a cross-sectional view of a canned food product with a jig attached, including the microwave heating jig shown in FIG. [Figure 10] FIG. 10 is a cross-sectional view showing the jig-attached canned product shown in FIG. 9 in which the attachment position of the microwave oven heating jig has been changed. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are more specific embodiments of any of the above aspects. The following items can be incorporated into each of the above aspects, either singly or in combination.

[0019] Fig. 1 is a perspective view of a microwave heating jig according to one embodiment of the present invention. Fig. 2 is another perspective view of the microwave heating jig shown in Fig. 1. Fig. 3 is a cross-sectional view taken along line III-III of the microwave heating jig shown in Fig. 1.

[0020] The microwave oven heating jig 10A shown in Figures 1 to 3 is used to place a metal can container in a microwave oven with the metal can container positioned at a greater distance from the bottom of the microwave oven when heating an item contained in the metal can container in a microwave oven. The microwave oven heating jig 10A is made of a non-metallic material. The microwave oven heating jig 10A includes a support portion 11 and a reinforcing portion 12.

[0021] The support portion 11 has a cylindrical shape. Here, the support portion 11 has a substantially cylindrical shape in which the diameter of one opening is smaller than the diameter of the other opening.

[0022] When microwave heating jig 10A is used in a microwave oven, the larger diameter opening of support part 11 is positioned above the smaller diameter opening. Hereinafter, with respect to microwave heating jig 10A and its components, the terms "above" and "below" are used in reference to the relative positions when microwave heating jig 10A is used in the microwave oven.

[0023] The reinforcing part 12 has a disk shape and is connected to the lower opening of the support part 11. The reinforcing part 12 improves the shape retention of the support part 11.

[0024] Here, the reinforcing part 12 is provided so as to close the lower opening of the support part 11. The reinforcing part 12 may be provided with one or more through holes. Also, here, the lower surface of the reinforcing part 12 is flush with the lower end surface of the support part 11. The lower surface of the reinforcing part 12 may be located higher than the lower end surface of the support part 11.

[0025] In this microwave heating jig 10A, the support part 11 is configured to fit into both a first canned product end and a second canned product end that differ from each other in at least one of shape and size. The first canned product end and the second canned product end may be the upper and lower ends of the same canned product, or may be the lower ends of different canned products. Here, as an example, the first canned product end is one of the upper and lower ends of a canned product, and the second canned product end is the other of the upper and lower ends of this canned product. Also, here, as an example, the first canned product end and the second canned product end are different in diameter.

[0026] As will be described later, when an item contained in a metal can container is heated in a microwave oven, the lower end of the canned product is inserted into the upper end of support portion 11 (hereinafter sometimes referred to as the open end of microwave heating jig 10A) of microwave heating jig 10A, supporting the canned product so that the metal can container is sufficiently spaced from the bottom surface of the microwave oven chamber. Furthermore, microwave heating jig 10A allows the canned product, heated to a high temperature, to be removed from the microwave oven chamber without touching it by manually carrying microwave heating jig 10A attached to the lower end of the canned product to the outside of the microwave oven. Because support portion 11 of microwave heating jig 10A fits into the lower end of the canned product, the canned product is less likely to shift position relative to microwave heating jig 10A during removal, and therefore unintended contact with the heated canned product or the item contained therein is less likely to occur. Furthermore, when the canned product is distributed or when an opened canned product is stored, the upper end of the canned product is inserted into the opening end of the microwave heating jig 10A, thereby protecting the upper surface of the canned product and items contained in the metal can container from dirt, etc.

[0027] The structure of the support portion 11 will be described in more detail below. Here, the support portion 11 includes a base portion 11b, a first fitting portion 11g1, and an expanded diameter portion 11e.

[0028] Base 11b has a cylindrical shape with a constant inner diameter in the height direction. Here, base 11b is continuous with reinforcing portion 12 at its lower end. Base 11b is positioned between the metal can and the interior bottom of the microwave oven when heating an item stored in the metal can in a microwave oven, and serves to widen the distance between the metal can and the interior bottom of the microwave oven. Base 11b may have a diameter that widens upward.

[0029] The first fitting portion 11g1 is a portion located between the base portion 11b and the expanded diameter portion 11e. The first fitting portion 11g1 is a portion that fits into the large diameter portion of the first canned product end. Here, the first fitting portion 11g1 has a cylindrical shape with a first groove extending in the circumferential direction provided on its inner surface. The first groove enables the microwave heating jig 10A to fit into the large diameter portion of the first canned product end. The first fitting portion 11g1 may have a cylindrical shape with a first groove extending in the circumferential direction provided on its inner surface and a diameter that tapers downward. Alternatively, the first fitting portion 11g1 may have one or more protrusions provided on its inner surface instead of the first groove, which enable the microwave heating jig 10A to fit into the large diameter portion of the first canned product end.

[0030] The expanded diameter portion 11e has a cylindrical shape whose diameter expands in a direction away from the first fitting portion 11g1. The expanded diameter portion 11e includes a second fitting portion 11g2 that fits with a large-diameter portion of the second canned product end portion. Here, the second fitting portion 11g2 has a second groove extending in the circumferential direction on its inner surface. The second groove allows the microwave heating jig 10A to engage with the large-diameter portion of the second canned product end portion. The inner diameter of the second fitting portion 11g2 at the position of the bottom of the second groove is larger than the inner diameter of the first fitting portion 11g1 at the position of the bottom of the first groove. Instead of a second groove, the second fitting portion 11g2 may have one or more protrusions on its inner surface that allow the microwave heating jig 10A to engage with the large-diameter portion of the second canned product end portion.

[0031] The microwave heating jig 10A preferably increases the distance between the metal can and the bottom surface of the microwave oven chamber to within a range of 1 mm to 50 mm, and more preferably to within a range of 10 mm to 30 mm. Increasing this distance reduces the likelihood of sparks occurring between the metal can and the bottom surface of the microwave oven chamber. However, increasing this distance increases the bulk of the microwave heating jig 10A or the canned food product that includes the jig and the canned food product. Furthermore, increasing this distance excessively shortens the distance from the metal can to the top surface of the microwave oven chamber, making it more likely that sparks will occur between them. Note that, in this case, this distance is approximately equal to the height of the base 11b.

[0032] The microwave oven heating jig 10A has a relative dielectric constant of 5 or less at 2.45 GHz and a dielectric loss tangent of 7.0 × 10 at 2.45 GHz. -3 It is preferable that the material is made of a material that satisfies the following conditions. Here, 2.45 GHz is the frequency of microwaves used in microwave ovens. The dielectric loss tangent is a value obtained by measuring at a temperature of 23±5°C and a humidity of 50±10% RH using the method specified in JIS K6911-1995.

[0033] This material preferably has a relative dielectric constant of 4.0 or less at 2.45 GHz. Although there is no lower limit to the relative dielectric constant of this material at 2.45 GHz, most materials suitable for microwave oven heating jig 10A have a relative dielectric constant of 2.0 or more at 2.45 GHz.

[0034] This material also has a dielectric loss tangent of 6.0×10 at 2.45 GHz. -3 Preferably, it is 5.0 x 10 or less. -3 More preferably, it is 4.0×10 or less. -3 Although there is no lower limit to the dielectric loss tangent of this material at 2.45 GHz, many materials suitable for microwave oven heating jig 10A have a dielectric loss tangent of 1.0×10 at 2.45 GHz or less. -5 That's all.

[0035] Examples of materials having the above physical properties include specific cured resins. The cured resins are, for example, cured thermosetting resins or cured thermoplastic resins. When the material is a cured resin, microwave heating jig 10A can be, for example, a molded product formed as a single unit.

[0036] Examples of cured resins having the above physical properties include polystyrene (PS), acrylonitrile-butadiene-styrene copolymer (ABS), polyamide-imide (PAI), high impact polystyrene (HIPS), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), polycarbonate (PC), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polypropylene (PP), polytetrafluoroethylene (PTFE), and polyethylene (PE).

[0037] Among these, acrylonitrile-butadiene-styrene copolymer (ABS), polyamide-imide (PAI), high impact polystyrene (HIPS), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), polycarbonate (PC), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polypropylene (PP), polytetrafluoroethylene (PTFE), and polyethylene (PE) are preferred.

[0038] Among these, acrylonitrile-butadiene-styrene copolymer (ABS), high impact polystyrene (HIPS), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), polycarbonate (PC), polypropylene (PP), polytetrafluoroethylene (PTFE), and polyethylene (PE) are particularly preferred.

[0039] Figure 4 is a cross-sectional view of a jig-attached canned product including the microwave heating jig shown in Figures 1 to 3. Figure 5 is a cross-sectional view showing the jig-attached canned product shown in Figure 4 with the microwave heating jig attached to a different position.

[0040] The jig-attached canned product 1A shown in Figs. 4 and 5 includes the microwave heating jig 10A and the canned product 20A.

[0041] The canned product 20A includes a metal can container 21 and an item 22 contained therein.

[0042] The metal can container 21 is a three-piece can in which the can bottom 21b and the can body 21a are integrated by double seaming, and the can lid 21c and the can body 21a are integrated by double seaming. The can lid 21c here includes a disk-shaped can lid body 21c1 with scores such as V-grooves on its surface and a pull tab 21c2 attached to it. Pulling the pull tab 21c2 can cause the can lid body 21c1 to break along the scores. The can lid 21c may also be a disk-shaped can lid body without scores such as V-grooves on its surface and without a pull tab attached.

[0043] The item 22 contains water. In this example, the item 22 is a food product containing a first food product 22a and a second food product 22b. At least one of the first food product 22a and the second food product 22b contains water. In one example, the first food product 22a is a solid food product containing water, and the second food product 22b is a liquid food product such as a seasoning liquid. The item 22 containing such a first food product 22a and a second food product 22b is, for example, yakitori or corn soup. One of the first food product 22a and the second food product 22b may be omitted.

[0044] Here, S / V ( / cm) is defined by defining the area of ​​the opening created in the can lid 21c of the metal can container 21 by opening the lid as S and the volume of the item 22 as V. The canned product 20A preferably has an S / V of 6 / cm or more, more preferably 15 / cm or more. Microwaves can be incident on the item 22 only through the opening created in the can lid by opening the lid. Increasing S / V enables more efficient heating. There is no upper limit to S / V, but in one example, S / V is 45 / cm or less.

[0045] The metallic can container 21 has a double seamed portion at its lower end as a large-diameter portion 21e1 and a double seamed portion at its upper end as a large-diameter portion 21e2. Each of the large-diameter portions 21e1 and 21e2 forms a circumferentially extending ridge-like protrusion on the outer circumferential surface of the metallic can container 21. The outer diameter of the large-diameter portion 21e2 at the upper end of the metallic can container 21 is larger than the outer diameter of the large-diameter portion 21e1 at the lower end. The large-diameter portion 21e1 at the lower end of the metallic can container 21 fits into the first fitting portion 11g1, and the large-diameter portion 21e2 at the upper end of the metallic can container 21 fits into the second fitting portion 11g2. The outer diameter of the large-diameter portion 21e2 at the upper end of the metallic can container 21 may be smaller than the outer diameter of the large-diameter portion 21e1 at the lower end.

[0046] In Fig. 4, the upper end of the metallic can container 21 is inserted into the opening end of the microwave oven heating jig 10A so that the ridge-like convex portion formed on the outer peripheral surface of the metallic can container 21 by the large diameter portion 21e2 is positioned in the second groove of the second fitting portion 11g2. In Fig. 5, the lower end of the metallic can container 21 is inserted into the opening end of the microwave oven heating jig 10A so that the ridge-like convex portion formed on the outer peripheral surface of the metallic can container 21 by the large diameter portion 21e1 is positioned in the first groove of the first fitting portion 11g1.

[0047] FIG. 6 is a perspective view showing an example of a microwave oven in which the microwave oven heating jig shown in FIGS. 1 to 3 can be used.

[0048] 6 is a so-called flat table type microwave oven that does not have a turntable. Microwave oven 100 includes microwave oven body 110 and door 120.

[0049] Microwave oven body 110 has a heating chamber surrounded by metal plates and open at the front. Of the surfaces of these metal plates, Fig. 3 illustrates interior bottom surface W1, which is the surface of the bottom plate, interior side surface W2, which is the surface of the left side panel, and interior side surface W3, which is the surface of the back side panel.

[0050] An opening is provided in the rear side panel. A waveguide is installed between this opening and the magnetron. A cover body 111 that covers the opening is attached to the rear side panel. The cover body 111 is made of, for example, mica, and allows microwaves to pass through.

[0051] The microwave heating jig 10A shown in Figures 1 and 2 may be used in a so-called turntable-type microwave oven that has a turntable. Furthermore, the microwave heating jig 10A shown in Figures 1 and 2 may be used in a microwave oven that has an opening in the right or left side panel and is configured to introduce microwaves into the heating chamber through this opening, in a microwave oven that has an opening in the bottom panel and is configured to introduce microwaves into the heating chamber through this opening, or in a microwave oven that has an opening in the top panel and is configured to introduce microwaves into the heating chamber through this opening.

[0052] FIG. 7 is a cross-sectional view showing the state in which an open canned product is placed on the bottom surface of the microwave oven via the microwave oven heating jig shown in FIGS.

[0053] Figure 7 shows one embodiment in which microwave heating jig 10A described with reference to Figures 1 to 3 is used to heat canned product 20A in microwave oven 100 described with reference to Figure 6. Figure 7 shows only bottom plate 112 of microwave oven 100, the upper surface of which is interior bottom surface W1. Canned product 20A shown in Figure 7 is obtained by removing the portion of can lid body 21c1 surrounded by the scores together with pull-tab 21c2 from canned product 20A shown in Figures 4 and 5 by pulling pull-tab 21c2, thereby turning can lid body 21c1 into can lid body 21c1' that is open in the center.

[0054] When heating the items 22 in the metal can container 21 in the microwave oven 100, first, as shown in Fig. 7, the microwave heating jig 10A is attached to the bottom end of the open canned product 20A. Specifically, the bottom end of the canned product 20A is inserted into the open end of the microwave heating jig 10A until the large diameter portion 21e1 at the bottom end of the metal can container 21 is fitted into the first groove provided on the inner surface of the first fitting portion 11g1. The canned product 20A may be opened after the microwave heating jig 10A has been attached to the bottom end of the canned product 20A.

[0055] Next, canned product 20A with microwave heating jig 10A attached to its lower end is placed on interior bottom surface W1 of microwave oven 100 so that base 11b is positioned below canned product 20A. Canned product 20A is preferably placed approximately in the center of interior bottom surface W1.

[0056] In this way, the metal can container 21 is placed inside the microwave oven 100 with the distance from the interior bottom surface W1 increased. Specifically, the metal can container 21 is placed inside the microwave oven with the distance increased by the height of the base 11b compared to when the canned product 20A is placed on the interior bottom surface W1 without the microwave oven heating jig 10A.

[0057] Thereafter, the door 120 of the microwave oven 100 is closed, and microwave irradiation is performed by the microwave oven 100. Since the lid of the canned product 20A is open, microwaves can be incident on the item 22. Therefore, the item 22 is heated.

[0058] In the above method, the microwave heating jig 10A is attached to the bottom end of the canned product 20A, thereby increasing the distance from the interior bottom surface W1 of the microwave oven 100 to the metallic can container 21. Increasing this distance reduces the gradient of the electric field therebetween, making it less likely that sparks will occur. Therefore, when the item 22 stored in the metallic can container 21 is heated in the microwave oven 100, it is possible to prevent problems caused by the metal.

[0059] Furthermore, microwave heating jig 10A can be used as an aid for removing heated canned products 20A from the oven. That is, when removing heated canned products 20A from the oven, microwave heating jig 10A attached to the bottom end of canned products 20A is manually carried outside the oven, whereby canned products 20A and microwave heating jig 10A can be removed from the oven without coming into contact with canned products 20A, which are at a higher temperature than microwave heating jig 10A.

[0060] Furthermore, in the above method, microwave heating jig 10A is attached to the bottom end of canned product 20A, and then they are placed inside microwave oven 100. Support portion 11 of microwave heating jig 10A is configured to fit into the bottom end of canned product 20A, so that, for example, when placing canned product 20A and microwave heating jig 10A inside the microwave oven or when removing them from the microwave oven, the canned product 20A is less likely to shift in position relative to microwave heating jig 10A. Therefore, for example, when removing canned product 20A and microwave heating jig 10A from the microwave oven, unintentional contact with canned product 20A or item 22 that has been heated to a high temperature is less likely to occur. Furthermore, if microwave oven 100 has a turntable, the above-mentioned positional shift caused by the rotation of the turntable is less likely to occur.

[0061] In the above-described method, when microwave oven heating jig 10A is attached to the bottom end of canned product 20A, the ridge-like protrusions formed on the outer surface of metal can container 21 by large-diameter portion 21e1 fit into the first groove formed on the inner surface of first fitting portion 11g1, thereby engaging microwave oven heating jig 10A with the bottom end of canned product 20A. Therefore, when placing canned product 20A with microwave oven heating jig 10A attached to its bottom end inside the microwave oven, for example, canned product 20A can be placed on microwave oven bottom surface W1 of microwave oven 100 so that base 11b is positioned below canned product 20A by carrying it inside the microwave oven with one hand. This engagement also makes it less likely that canned product 20A will shift position when removed from the microwave oven or when the turntable is rotated.

[0062] Furthermore, when the canned product 20A is unopened, as shown in Fig. 4, by attaching a microwave heating jig 10A to the upper end of the canned product 20A, the upper surface of the canned product 20A can be protected from dirt and the like. Also, by attaching the microwave heating jig 10A to the upper end of the canned product 20A during storage of an opened canned product 20A, it is possible to prevent foreign matter from being mixed into the item 22 contained in the metal can container 21 and to prevent liquid components contained in the item 22 from evaporating. Because the microwave heating jig 10A engages with the upper end of the canned product 20A, it is less likely to fall off the canned product 20A unintentionally.

[0063] Furthermore, when the microwave oven heating jig 10A is made of a material having the above-mentioned relative permittivity and dielectric loss tangent, it further exhibits the effects described below.

[0064] As described above, when a container body made of a composite sheet containing a resin sheet and a metal foil formed into a cup shape is placed in a paper box and the contents of the container body are heated in a microwave oven in this state, sparks are unlikely to occur. However, the inventors have found that when a metal can is used instead of the above-mentioned container body, although sparks are unlikely to occur, the paper may become scorched.

[0065] The inventors of the present invention believe that one of the causes of this scorching is the moisture contained in the paper. That is, because paper contains moisture, the temperature of the paper rises rapidly when irradiated with microwaves. The inventors of the present invention believe that this makes the paper more susceptible to scorching.

[0066] Therefore, the inventors investigated the effect of the moisture content of paper on the occurrence of scorching, and surprisingly found that the moisture content of paper does not affect the occurrence of scorching.

[0067] The inventors of the present invention further investigated the possibility that the main cause of scorching lies elsewhere. Specifically, they hypothesized that microwaves act on components such as cellulose contained in paper, or on their functional groups or bonds, causing scorching on paper containers. Based on this hypothesis, they investigated whether or not various materials would scorch when irradiated with microwaves. They found that all materials whose temperature did not rise excessively when irradiated with microwaves possessed the above-mentioned physical properties.

[0068] Furthermore, by increasing the distance from the interior bottom surface W1 to the metallic can container 21, the gradient of the electric field therebetween can be reduced, as described above, making it less likely that sparks will occur. Increasing this distance also reduces the confinement of microwaves in the area between the interior bottom surface W1 and the bottom surface of the metallic can container 21, which is caused by microwave reflection by these two surfaces, and also prevents excessive irradiation of microwaves to the microwave oven heating jig 10A.

[0069] Therefore, when heating an item 22 contained in a metal can container 21 in a microwave oven 100, by using a microwave heating jig 10A made of a material having the above physical properties and increasing the distance from the bottom surface W1 of the oven interior to the metal can container 21, it is possible to prevent sparks from occurring and the jig from burning or melting.

[0070] The microwave heating jig and the canned product with the jig can be modified in many ways. FIG. 8 is a perspective view of a microwave heating jig according to a modified example. The microwave oven heating jig 10B shown in FIG. 8 is similar to the microwave oven heating jig 10A described with reference to FIGS. 1 to 3, etc., except for the following points.

[0071] That is, compared to microwave heating jig 10A, microwave heating jig 10B has a larger height dimension of first fitting portion 11g1 and a larger width of the first groove provided on the inner surface of first fitting portion 11g1. Also, microwave heating jig 10B has a support portion 11 that includes second fitting portion 11g2 and middle portion 11m instead of expanded diameter portion 11e.

[0072] The intermediate portion 11m is a portion located between the first fitting portion 11g1 and the second fitting portion 11g2. The intermediate portion 11m has a cylindrical shape with an inner diameter that is constant in the height direction. The inner diameter of the intermediate portion 11m is slightly smaller than the inner diameter of the first fitting portion 11g1 at the position of the bottom surface of the first groove. The intermediate portion 11m may have a cylindrical shape that expands in diameter toward the open end of the microwave oven heating jig 10B. In this case, the inner diameter of the intermediate portion 11m on the side of the first fitting portion 11g1 and the inner diameter on the side of the second fitting portion 11g2 are smaller than the inner diameter of the first fitting portion 11g1 at the position of the bottom surface of the first groove and the inner diameter of the second fitting portion 11g2 at the position of the bottom surface of the second groove, respectively.

[0073] The second fitting portion 11g2 has a generally cylindrical shape. A second groove extending in the circumferential direction is provided on the inner surface of the second fitting portion 11g2. The inner diameter of the second fitting portion 11g2 at the position of the bottom surface of the second groove is larger than the inner diameter of the intermediate portion 11m.

[0074] Fig. 9 is a cross-sectional view of a jig-attached canned product including the microwave heating jig shown in Fig. 8. Fig. 10 is a cross-sectional view showing the jig-attached canned product shown in Fig. 9 with the microwave heating jig attached to a different position.

[0075] Jig-attached canned product 1B shown in Figures 9 and 10 is similar to jig-attached canned product 1A described with reference to Figures 4 and 5, respectively, except for the following points: Jig-attached canned product 1B includes microwave heating jig 10B and canned product 20B instead of microwave heating jig 10A and canned product 20A.

[0076] The canned product 20B is similar to the canned product 20A described with reference to Figures 4 and 5, except for the following points. Specifically, the metal can container 21 included in the canned product 20B is a two-piece can in which the can bottom 21b and the can body 21a are integrally formed. The can body 21a has an expanded diameter portion near its lower end. This metal can container 21 has the expanded diameter portion provided near the lower end of the can body 21a as a large diameter portion 21e1, and the double-seamed portion at the upper end as a large diameter portion 21e2. The metal can container 21 has different shapes at its upper and lower ends.

[0077] As shown in Fig. 9, when the microwave heating jig 10B is attached to the upper end of the canned product 20B, the ridge-like protrusions formed on the outer peripheral surface of the metal can container 21 by the large diameter portion 21e2 fit into the second groove provided on the inner surface of the second fitting portion 11g2, thereby locking the microwave heating jig 10B to the upper end of the canned product 20B. Also, as shown in Fig. 10, when the microwave heating jig 10B is attached to the lower end of the canned product 20B, the ridge-like protrusions formed on the outer peripheral surface of the metal can container 21 by the large diameter portion 21e1 are positioned below the middle portion 11m, thereby locking the microwave heating jig 10B to the lower end of the canned product 20B. In this modified example, the same effects as those of the above embodiment can be obtained.

[0078] As described above, the metal can container included in the canned product to be combined with the microwave oven heating jig may be a three-piece can or a two-piece can.

[0079] Each of microwave heating jigs 10A and 10B has a circular shape when orthogonally projected onto a plane perpendicular to its height direction. The shape of the microwave heating jigs when orthogonally projected onto a plane perpendicular to its height direction does not have to be circular. For example, the shape of the microwave heating jigs when orthogonally projected onto a plane perpendicular to its height direction may be a square, a rectangle, a square with rounded corners, or a rectangle with rounded corners.

[0080] The microwave heating jig can be distributed alone. Alternatively, the microwave heating jig can be combined with unopened canned products and distributed as a jig-attached canned product. In a jig-attached canned product, the number of microwave heating jigs and the number of canned products may be the same or different. In the latter case, the jig-attached canned product may include, for example, one microwave heating jig and multiple canned products.

[0081] The microwave heating jig can also be combined with empty metal can containers and distributed as a kit for canned products with a jig. In the kit for canned products with a jig, the number of microwave heating jigs and the number of metal can containers may be the same or different. In the latter case, the canned product with a jig may include, for example, one microwave heating jig and multiple metal can containers. [Example]

[0082] The following describes tests carried out in connection with the present invention.

[0083] <1> The effect of moisture on the occurrence of burning or melting A 0.6 mm thick polypropylene sheet was left in a room environment for a long time. Then, several square samples, each measuring 10 cm on a side, were cut out from the sheet. The masses (initial masses) of these samples were measured, and then they were divided into groups A, B, and C.

[0084] For each sample in group A, the following heating test was carried out immediately after the initial mass measurement. A flat tabletop microwave oven was used for the heating test. The sample was placed approximately in the center of the flat turntable. A metal can with its lid open and containing 70 g of tap water was placed on the sample. The metal can was a three-piece can with an aluminum lid, a steel body, and a steel bottom, an opening diameter of 72 mm, and a height of 30 mm. The sample was heated at 500 W for 30 seconds. Immediately after heating, the metal can was removed from the sample, and the entire sample was imaged with an infrared thermography camera. The maximum temperature of the sample was determined from the image obtained. The sample after microwave heating was also imaged with a conventional camera, and the image was observed. The sample was also visually inspected for the occurrence of scorching or melting.

[0085] After measuring the initial mass of each sample in Group B, the sample was dried for 7 days in a hygrostat set at 50°C. The mass after drying was measured, and then the heating test described above was carried out. This resulted in obtaining the maximum temperature of the sample. The sample was then examined for the occurrence of scorching or melting using the same method as described above.

[0086] For each sample in Group C, after measuring the initial mass, it was dried for 7 days in a hygrostat set at 50°C. The mass after drying was measured, and then the sample was allowed to absorb moisture for 7 days in a hygrostat set at 50% RH and 23°C. The heating test was then performed to obtain the maximum temperature of the sample. The occurrence of scorching or melting in the sample was then examined using the same method as above.

[0087] Sheets made from different materials were also subjected to the same tests as for the polypropylene sheet, and the results are shown in Table 1 below.

[0088] [Table 1]

[0089] In Table 1, the abbreviation "PBS / PLA" represents polybutylene succinate / polylactic acid blend resin. "A" indicates that no scorching or melting was observed in either the naked eye or the image of the sample. "B" indicates that no scorching or melting was observed in the image, but scorching or melting was not noticeable at first glance when the sample was observed with the naked eye. "C" indicates that no scorching or melting was clearly observed in the image, but scorching or melting was clearly noticeable at first glance when the sample was observed with the naked eye. "D" indicates that scorching or melting was clearly observed just by observing the image.

[0090] As shown in Table 1, no correlation was observed between the moisture content of the sheet and the maximum temperature. Also, no correlation was observed between the moisture content of the sheet and the occurrence of burning or melting.

[0091] <2> The effect of the type of jig material on the occurrence of burning or melting A microwave heating jig was created from the materials shown in Table 2 below. The microwave heating jig was created so that, when used, the distance from the bottom of the microwave oven to the metal can container would be increased to 1.0 cm. In Table 2, the abbreviation "A-PET" stands for amorphous polyethylene terephthalate, the abbreviation "POM" stands for polyacetal, the abbreviation "PA" stands for polyamide (here, nylon 66), the abbreviation "PBS / PLA" stands for polybutylene succinate / polylactic acid blend resin, and the abbreviation "PVDF" stands for polyvinylidene fluoride.

[0092] In addition, a paper box was created as a microwave oven heating jig. This paper box was formed into a rectangular parallelepiped shape with a square bottom. The base of the rectangular parallelepiped was 6 cm and the height was 1.0 cm.

[0093] Next, the following heating test was carried out. A flat-table microwave oven was used for the heating test. The microwave heating jig was placed approximately in the center of the flat table. A metal can with its lid open and containing 70 g of tap water was placed on the microwave heating jig. The metal can was a three-piece can with an aluminum lid, a steel body, and a steel bottom, an opening diameter of 72 mm, and a height of 30 mm. The can was then heated in a microwave oven at 500 W for 60 seconds. After that, the microwave heating jig sample was photographed with a conventional camera, and the image was observed. The microwave heating jig sample was also visually inspected for the occurrence of burning or melting. The results are shown in Table 2 below.

[0094] [Table 2]

[0095] The evaluation criteria for "burnt / melted state" in Table 2 are the same as the evaluation criteria for "burnt / melted state" in Table 1.

[0096] In addition to the above evaluation results, Table 2 also shows the dielectric constant at 2.45 GHz and the dielectric loss tangent (tan δ) at 2.45 GHz. The dielectric constant of PTFE is a value at 10 GHz, but its dielectric constant at 2.45 GHz is in the range of 1 to 5. The dielectric constants of PVC, PMMA, and PVDF are values ​​at 1 GHz, but their dielectric constants at 2.45 GHz are in the range of 1 to 5.

[0097] As shown in Table 2, the dielectric loss tangent is 7.0 × 10 -3 The microwave heating jig made of the material below did not show any noticeable burning or melting. -3 The microwave heating jigs made of the following materials did not burn or melt. [Explanation of symbols]

[0098] 1A...canned product with jig, 1B...canned product with jig, 10A...microwave oven heating jig, 10B...microwave oven heating jig, 11...support portion, 11b...base portion, 11e...expanded diameter portion, 11g1...first fitting portion, 11g2...second fitting portion, 11m...middle portion, 12...reinforcing portion, 20A...canned product, 20B...canned product, 21...metal can container, 21a...can body, 21b ...can bottom, 21c...can lid, 21c1...can lid body, 21c1'...can lid body, 21c2...pull tab, 21e1...large diameter portion, 21e2...large diameter portion, 22...item, 22a...first food, 22b...second food, 100...microwave oven, 110...microwave oven body, 111...cover body, 112...bottom plate, 120...door, W1...interior bottom surface, W2...interior side surface, W3...interior side surface.

Claims

1. A non-metallic microwave heating tool used to place a metal can container in a microwave oven with a wider distance from the bottom of the microwave oven when heating an item contained in the metal can container in a microwave oven, The support member includes a cylindrical support portion and a flat plate-shaped reinforcing portion connected to one opening of the support portion, The support portion is configured to fit onto both a first canned product end portion and a second canned product end portion which are different from each other in at least one of shape and size.

2. 2. The microwave heating jig of claim 1, wherein the first canned product end and the second canned product end include a large diameter portion, and the support portion includes a first fitting portion that fits with the large diameter portion of the first canned product end and a second fitting portion that fits with the large diameter portion of the second canned product end.

3. The relative dielectric constant at 2.45 GHz is 5 or less and the dielectric loss tangent at 2.45 GHz is 7.0 × 10 －３ 2. The microwave heating jig according to claim 1, which is made of the following material:

4. 4. The microwave oven heating jig according to claim 3, wherein the material is a cured resin.

5. a canned product including the metal can container and the item contained therein; The microwave heating jig according to any one of claims 1 to 4. A canned product with a jig attached.

6. 6. The jig-attached canned product of claim 5, wherein the canned product has an upper end as one of the first canned product end and the second canned product end, and a lower end as the other of the first canned product end and the second canned product end.

7. The microwave heating jig according to any one of claims 1 to 4, The metal can container, A kit for canned products with a jig.

8. 8. The kit for canned products with a jig as described in claim 7, wherein the canned product including the metal can container and the item contained therein has an upper end portion as one of the first canned product end portion and the second canned product end portion, and a lower end portion as the other of the first canned product end portion and the second canned product end portion.

Images