Canned products with jigs

Abstract

To provide a technique for distributing canned products in the form of jig-attached canned products by attaching a jig for microwave heating to the canned products. [Solution] A jig-attached canned product (1) comprises a canned product (20) including a metal can container (21) and an item (22) contained therein, and a non-metallic microwave heating jig (10) used to place the metal can container (21) in a microwave oven with a wider distance from the bottom of the oven when heating the item (22) contained in the metal can container (21) in a microwave oven, and the canned product (20) and the microwave heating jig (10) are arranged so that they are aligned in the height direction of the canned product (20), and the height of the jig-attached canned product (1) and the height of the canned product (20) satisfy the following inequality: 0.9×(n+1)×Hk≦n×Ht≦1.1×(n+1)×Hk (where n represents an integer ranging from 2 to 5) is satisfied.

Description

[Technical Field]

[0001] The present invention relates to a jig-attached canned product. [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] Japanese Patent Application Laid-Open No. 2017-95163 Summary of the Invention [Problem to be solved by the invention]

[0007] The present inventors have developed a microwave heating jig that can prevent metal-related defects from occurring when heating items stored in metal cans in a microwave oven. Accordingly, the present invention aims to provide a technology for attaching the microwave heating jig to canned products and distributing them as canned products with the jig attached. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided a canned product including a metal can container and an item contained therein, and a non-metallic microwave heating jig used to install the metal can container in a microwave oven with a wider distance from the bottom surface of the microwave oven when heating the item contained in the metal can container in a microwave oven, wherein the canned product and the microwave heating jig are arranged side by side in a height direction of the canned product, and the height Ht of the jig-attached canned product and the height Hk of the canned product are determined by the following inequality (1): 0.9×(n+1)×Hk≦n×Ht≦1.1×(n+1)×Hk (where n represents an integer ranging from 2 to 5) According to another aspect of the present invention, the microwave oven heating jig 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 There is provided a jig-attached canned product according to the above aspect, which is made of the following material:

[0009] According to yet another aspect of the present invention, there is provided a canned food product with a jig according to any one of the above aspects, wherein the microwave heating jig is made of a cured resin.

[0010] According to yet another aspect of the present invention, there is provided a canned product with a jig according to any of the above aspects, in which the microwave heating jig has an overall cylindrical shape and is attached to the upper end of the canned product.

[0011] According to yet another aspect of the present invention, there is provided a packaged article comprising a plurality of jig-attached canned products stacked vertically and a packaging material containing or holding together the plurality of jig-attached canned products, each of the plurality of jig-attached canned products being a jig-attached canned product as defined in any one of claims 1 to 4.

[0012] According to yet another aspect of the present invention, there is provided a jig-attached canned product comprising a metal can container for containing an item heatable in a microwave oven, and a non-metallic microwave heating jig, wherein the microwave heating jig is arranged in line with the height of the canned product when the jig-attached canned product is distributed, the jig including the item and the metal can container containing the item, and the microwave heating jig; and when the item contained in the metal can container is heated in a microwave oven, the metal can container is placed in the microwave oven with its distance from the bottom surface of the microwave oven increased, and the height Ht of the jig-attached canned product and the height Hk of the canned product are determined by the following inequality (1): 0.9×(n+1)×Hk≦n×Ht≦1.1×(n+1)×Hk (where n represents an integer ranging from 2 to 5) is satisfied. [Effects of the Invention]

[0013] According to the present invention, a technique is provided for attaching a microwave oven heating jig to a canned product and distributing the canned product in the form of a jig-attached canned product. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view of a microwave oven heating jig according to one embodiment. [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] Figure 5 is a front view showing (a) the state in which the canned products included in the jig-attached canned product shown in Figure 4 are stacked in the vertical direction, and (b) the state in which the jig-attached canned products shown in Figure 4 are stacked in the vertical direction. [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. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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.

[0016] 1. Canned products with microwave oven heating fixtures 1-1. Microwave heating tool Fig. 1 is a perspective view of a microwave heating jig according to one embodiment. Fig. 2 is another perspective view of the microwave heating jig shown in Fig. 1. Fig. 3 is a cross-sectional view of the microwave heating jig shown in Fig. 1 taken along line III-III.

[0017] The microwave heating jig 10 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 heating jig 10 is made of a non-metallic material. The microwave heating jig 10 includes a support portion 11 and a reinforcing portion 12.

[0018] The support portion 11 has a cylindrical shape. Here, the support portion 11 has a substantially cylindrical shape whose diameter increases from one opening to the other opening.

[0019] When microwave heating tool 10 is used in a microwave oven, the larger diameter opening in support portion 11 is positioned above the smaller diameter opening. Hereinafter, with respect to microwave heating tool 10 and its components, the terms "above" and "below" are used in reference to the relative positions when microwave heating tool 10 is used in the microwave oven.

[0020] The support portion 11 here includes a lower portion 11b, an upper portion 11t, and a middle portion 11m.

[0021] The lower portion 11b has a cylindrical shape whose diameter increases upward. Here, the lower portion 11b has a cylindrical shape whose diameter increases upward. The lower portion 11b may have a cylindrical shape whose inner diameter is constant in the height direction, for example, a cylindrical shape whose inner diameter is constant in the height direction.

[0022] The upper portion 11t has a cylindrical shape whose diameter increases upward. Here, the upper portion 11t has a cylindrical shape whose diameter increases upward. The upper portion 11t may have a cylindrical shape whose inner diameter is constant in the height direction, for example, a cylindrical shape whose inner diameter is constant in the height direction.

[0023] The inner surface of the upper portion 11t is provided with a plurality of protrusions 11p each extending in the circumferential direction. These protrusions 11p are arranged at a distance from each other in the longitudinal direction. Instead of providing a plurality of protrusions 11p on the inner surface of the upper portion 11t, a single protrusion extending in the circumferential direction may be provided around the entire surface.

[0024] The inner diameter of the lower end of the upper part 11t is larger than the inner diameter of the upper end of the lower part 11b. The upper part 11t is positioned such that its lower end surrounds the upper end of the lower part 11b.

[0025] The intermediate portion 11m connects the upper end of the lower portion 11b and the lower end of the upper portion 11t. The intermediate portion 11m has an annular upper surface, which is annular in this case.

[0026] As will be described later, when heating an item housed in a metal can in a microwave oven, the lower end of the canned product is inserted into the open end of the microwave heating jig 10, supporting the canned product so that the metal can is sufficiently spaced from the bottom surface of the microwave oven chamber. The microwave heating jig 10 can also be distributed as a jig-attached canned product in combination with a canned product. In one example, the jig-attached canned product has the upper end of the canned product inserted into the open end of the microwave heating jig 10. The upper surface of the middle portion 11m can form at least a part of the contact surface with which the upper end of the canned product abuts when the upper end of the canned product is inserted into the open end of the microwave heating jig 10.

[0027] Reinforcing portion 12 has a disk shape and closes the lower opening of supporting portion 11. Reinforcing portion 12 improves the shape retention of supporting portion 11. The edge of reinforcing portion 12 is continuous with the lower end of supporting portion 11. When microwave heating jig 10 is attached to the upper end of a canned product as described below, the lower surface of reinforcing portion 12 can be used as a display surface for displaying images, text, etc. using a printed layer or label.

[0028] The microwave heating jig 10 has four recesses R, each recessed toward the inside of the microwave heating jig 10, at the position of the ridge line 13 connecting the support part 11 and the reinforcing part 12. As will be described later, the recesses R serve to increase the strength of the microwave heating jig 10.

[0029] The recesses R each produce a protrusion P on the inner surface of the microwave heating jig 10. Here, the protrusion P has an upper surface that is equal in height to the upper surface of the middle portion 11m. In this case, the upper surface of the protrusion P can form another part of the contact surface described above.

[0030] Recesses R may be omitted if the upper surface of middle portion 11m of microwave heating jig 10 can support the canned product when it is inserted into the open end of microwave heating jig 10. The number of recesses R may be changed to any number equal to or greater than 1, and is preferably within the range of 1 to 17, and more preferably within the range of 2 to 12.

[0031] The microwave heating jig 10 preferably increases the distance between the metal can and the microwave oven's interior bottom surface 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 microwave oven's interior bottom surface. However, increasing this distance increases the bulk of the microwave heating jig 10 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 microwave oven's interior top surface, making sparks more likely to occur between them. Note that the above distance is approximately equal to the height of the middle portion 11m or the top surface of the protruding portion P relative to the bottom surface of the reinforcing portion 12.

[0032] It is preferable that microwave heating jig 10 has one or more through holes in its wall. The through holes provided in the wall of microwave heating jig 10 allow ventilation between the internal and external spaces of microwave heating jig 10 when microwave heating jig 10 is attached to canned goods and when microwave heating jig 10 is detached from canned goods, thereby reducing the pressure difference between these spaces. Therefore, by providing one or more through holes in the wall of microwave heating jig 10, it becomes easier to attach microwave heating jig 10 to canned goods and to detach microwave heating jig 10 from canned goods.

[0033] The microwave oven heating jig 10 has a relative dielectric constant of 5 or less at 2.45 GHz and a dielectric loss tangent of 7.0×10 -3It 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.

[0034] 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 heating jig 10 have a relative dielectric constant of 2.0 or more at 2.45 GHz.

[0035] 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 the microwave oven heating jig 10 have a dielectric loss tangent of 1.0×10 or less at 2.45 GHz. -5 That's all.

[0036] 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, the microwave heating jig 10 can be, for example, a molded product obtained by molding the entire jig as a single unit.

[0037] 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).

[0038] 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.

[0039] 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.

[0040] 1-2. Structure of canned products with jigs 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.

[0041] The jig-attached canned product 1 shown in Figure 4 includes the microwave heating jig 10 and the canned product 20. The canned product 20 and the microwave heating jig 10 are arranged side by side in the height direction of the canned product 20. Specifically, the microwave heating jig 10 has an overall cylindrical shape and is attached to the upper end of the canned product 20. It is preferable that the microwave heating jig 10 fits onto the upper end of the canned product 20 to form a fitted body together with the canned product 20.

[0042] The canned product 20 includes a metal can container 21 and an item 22 contained therein.

[0043] 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 metal can container 21 may also be a two-piece can in which the can bottom 21b and the can body 21a are integrally formed, and the can lid 21c and the can body 21a are integrated by double seaming.

[0044] Here, the can lid 21c includes a disk-shaped can lid body 21c1 having a score such as a V-groove on its surface and a pull tab 21c2 attached thereto. Pulling the pull tab 21c2 can cause the can lid body 21c1 to break along the score. The can lid 21c may be a disk-shaped can lid body without a score such as a V-groove on its surface and without a pull tab. Alternatively, the can lid 21c may be a can lid attached to a container body consisting of a can bottom 21b and a can body 21a in a resealable manner. An example of such a can lid is a cup-shaped can lid that fits over the opening of the container body and has a thread groove on its inner surface that threadably mates with a thread groove on the outer surface of the opening of the container body.

[0045] 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.

[0046] 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 20 preferably has an S / V of 6 / cm or more, and 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.

[0047] The can body 21a of the metal can container 21 has double-seamed portions at its upper and lower ends as enlarged diameter portions. In Fig. 4, the outer diameter of the double-seamed portion at the upper end of the metal can container 21 is larger than the outer diameter of the double-seamed portion at the lower end. In this case, as shown in Fig. 4, if the upper end of the canned product 20 can be inserted into the opening end of the microwave heating jig 10, the lower end of the canned product 20 can also be inserted into the opening end of the microwave heating jig 10.

[0048] 4, the outer diameter of the double-seamed portion at the top end of the metallic can container 21 is larger than the diameter of the circle inscribed in the protrusion 11p provided on the inner surface of the upper part 11t of the microwave oven heating jig 10. The protrusion 11p is located below the double-seamed portion at the top end of the metallic can container 21. In this way, the microwave oven heating jig 10 is fastened to the top end of the metallic can container 21.

[0049] In the jig-attached canned products 1, it is preferable that the inner diameter of the lower end of the metal can container 21, i.e., the inner diameter of the double-seamed portion at the lower end, is larger than the outer diameter of the end of the microwave heating jig 10 facing the reinforcement portion 12. When such jig-attached canned products 1 are stacked vertically, the end of the microwave heating jig 10 facing the reinforcement portion 12 of the lower jig-attached canned product 1 can be located within the area surrounded by the double-seamed portion at the lower end of the metal can container 21 of the upper jig-attached canned product 1. In other words, when the jig-attached canned products 1 are stacked, an overlapping portion may occur between them. This stabilizes the stacked state of the jig-attached canned products 1.

[0050] In the jig-attached canned product 1, the height Ht of the jig-attached canned product 1 and the height Hk of the canned product 20 are determined by the following inequality (1): 0.9×(n+1)×Hk≦n×Ht≦1.1×(n+1)×Hk (where n represents an integer ranging from 2 to 5) is satisfied.

[0051] The technical meaning of this inequality (1) is explained below. Existing canned products that do not come with microwave heating tools are produced by manufacturers, packaged in packing boxes such as cardboard boxes, transported by truck or ship, stored in a logistics warehouse, and then unpacked and displayed on display shelves at retail stores. In this distribution format, canned products are packed in packing boxes in a stacked state without leaving excessive gaps in the vertical direction of the packing box to prevent damage during transportation. Furthermore, canned products are arranged on display shelves in a stacked state without leaving excessive space in the vertical direction of the display shelf, taking into account shelf storage efficiency, while leaving appropriate gaps in the vertical direction to allow customers to remove canned products from the display shelf. In this way, the relationship between the overall height of the stacked canned products and the height of the packing box, and the relationship between the overall height of the stacked canned products and the height of the display shelf, are generally optimized.

[0052] When considering that jig-attached canned products 1 are distributed stacked in two to five layers using existing packaging boxes and existing display shelves used for existing canned products, it is desirable that the total height THt of n stacked jig-attached canned products 1 (n is an integer between 2 and 5) is approximately equal to the total height THk of the stacked (n+1) canned products 20. This relationship can be expressed as the above inequality (1).

[0053] The above inequality (1) indicates that the total height THt of the jig-attached canned products 1 when jig-attached canned products 1 with a height Ht are stacked in n layers (n is an integer between 2 and 5) is within the range of ±10% of the total height THk of the canned products 20 when canned products 20 with a height Hk are stacked in (n+1) layers. The total height THk of the canned products 20 can be expressed by equation (1a): (n+1) × Hk. Furthermore, the total height THt of the jig-attached canned products 1 can be expressed by equation (1b): n × Ht. As mentioned above, when jig-attached canned products 1 are stacked, there may be overlaps between them, but equation (1b) does not take such overlaps into account. Similarly, when canned products 20 are stacked, there may be overlaps between them, but equation (1a) does not take such overlaps into account.

[0054] Here, if the total height THt of the jig-attached canned products 1 is excessively greater than the total height THk of the canned products 20, it will be impossible to store n jig-attached canned products 1 in a stacked state in an existing packing box designed to pack (n+1) canned products 20 in a stacked state. Also, if the total height THt of the jig-attached canned products 1 is excessively greater than the total height THk of the canned products 20, it will be impossible to display n jig-attached canned products 1 in a stacked state on an existing display shelf designed to display (n+1) canned products in a stacked state, or even if it is possible to display n jig-attached canned products 1 in a stacked state on an existing display shelf, it will be difficult for customers to remove the jig-attached canned products 1 from the display shelf.

[0055] Alternatively, if the total height THt of the jig-attached canned products 1 is excessively smaller than the total height THk of the canned products 20, when n jig-attached canned products 1 are stored in a stacked state in an existing packaging box for packing (n+1) canned products in a stacked state, excessive gaps will be created in the vertical direction, resulting in problems such as reduced transport efficiency and susceptibility to shocks from vibrations during transport. Also, if the total height THt of the jig-attached canned products 1 is excessively smaller than the total height THk of the canned products 20, when n jig-attached canned products 1 are stacked and arranged on an existing display shelf for displaying (n+1) canned products in a stacked state, excess space will be created in the vertical direction, reducing the storage efficiency of the display shelf.

[0056] From the above, if the height Ht of jig-attached canned product 1 and the height Hk of canned product 20 satisfy the relationship shown in inequality (1) above, the height of jig-attached canned product 1 is adjusted so that it can be efficiently stored in an existing packing box or efficiently displayed on an existing display shelf, and it can be used without modifying the height of the existing packing box or the height of the existing display shelf. In other words, if the height Ht of jig-attached canned product 1 and the height Hk of canned product 20 satisfy the relationship shown in inequality (1) above, it can be said that the height of jig-attached canned product 1 is compatible with the height of the existing packing box or the height of the existing display shelf.

[0057] The above effect is exhibited when a plurality of jig-attached canned products 1 are stacked vertically for distribution. Therefore, in the jig-attached canned products 1, it is preferable that the number of microwave heating jigs 10 and the number of canned products 20 match.

[0058] Furthermore, when jig-attached canned product 1 is distributed, if microwave heating jig 10 is attached to the upper end of canned product 20, it is possible to prevent the upper surface of can lid 21c, i.e., the opening of the canned product, from becoming soiled, as shown in Figure 4. In this case, when canned product 20 is heated in a microwave oven, microwave heating jig 10 must be reattached to the can bottom 21b side of canned product 20, as will be described later.

[0059] In the jig-attached canned product 1, the height Ht of the jig-attached canned product 1 and the height Hk of the canned product 20 are determined by the following inequality (2): 0.95×(n+1)×Hk≦n×Ht≦1.05×(n+1)×Hk (where n is an integer ranging from 2 to 5) is preferably satisfied. Inequality (2) indicates that the total height THt of jig-attached canned products 1 when jig-attached canned products 1 with height Ht are stacked in n layers (n is an integer ranging from 2 to 5) is within the range of ±5% of the total height THk of canned products 20 when canned products 20 with height Hk are stacked in (n+1) layers.

[0060] In each of inequalities (1) and (2), n is preferably an integer in the range of 2 to 4, and n is more preferably 3 or 4.

[0061] The height Hk of the canned products 20 is, for example, in the range of 26 to 124 mm, and preferably in the range of 26 to 52 mm. The height of the microwave heating jig 10 is, for example, in the range of 4 to 83 mm, and preferably in the range of 6 to 43 mm.

[0062] Figure 5 shows an example of a case where two layers of jig-attached canned products 1 having the structure shown in Figure 4 are stacked. Figure 5 is a front view showing (a) the state in which the canned products included in the jig-attached canned product shown in Figure 4 are stacked in the height direction, and (b) the state in which the jig-attached canned products shown in Figure 4 are stacked in the height direction. Figure 5 shows that the total height THt of the jig-attached canned products 1 shown in Figure 4 when stacked in two layers is approximately the same as the total height THk of the canned products 20 included in this jig-attached canned product 1 when stacked in three layers.

[0063] In FIG. 5(a), the bottom end of the metal can container 21 constituting the upper canned product 20 is located within the area surrounded by the double-seamed portion of the top end of the metal can container 21 constituting the lower canned product 20. That is, when the canned products 20 included in the jig-attached canned product 1 shown in FIG. 4 are stacked, overlapping portions occur between the canned products 20, and the total height THk of the canned products 20 is slightly smaller than the value calculated by formula (1a): (n+1)×Hk. Specifically, if the height of the overlapping portion between the canned products 20 is represented by dH1, the total height THk of the canned products 20 is expressed by formula (3a): (n+1)×Hk-n×dH1. dH1 is, for example, within the range of 2 to 6 mm.

[0064] In addition, in FIG. 5(b), the end of the microwave heating jig 10 of the lower jig-attached canned product 1 on the side of the reinforcement 12 is located within the area surrounded by the double-seamed portion of the lower end of the metal can container 21 of the upper jig-attached canned product 1. That is, when the jig-attached canned products 1 shown in FIG. 4 are stacked, overlapping portions occur between the jig-attached canned products 1, and the total height THt of the jig-attached canned products 1 is slightly smaller than the value calculated by formula (1b): n × Ht. Specifically, if the height of the overlapping portion between the jig-attached canned products 1 is represented by dH2, the total height THt of the jig-attached canned products 1 can be expressed by formula (3b): n × Ht - (n - 1) × dH2. dH2 is, for example, within the range of 2 to 6 mm.

[0065] In this case, the height Ht of the jig-attached canned product 1 and the height Hk of the canned product 20 are determined by the following inequality (3): 0.9×{(n+1)×Hk-n×dH1}≦n×Ht-(n-1)×dH2≦1.1×{(n+1)×Hk-n×dH1} (where n represents an integer in the range of 2 to 5) is ideally satisfied.

[0066] However, in equation (3a): (n+1)×Hk-n×dH1, n is small and dH1 is small, so the second term of equation (3a) (i.e., n×dH1) is sufficiently smaller than the first term of equation (3a) (i.e., (n+1)×Hk). Similarly, in equation (3b): n×Ht-(n-1)×dH2, n is small and dH2 is small, so the second term of equation (3b) (i.e., (n-1)×dH2) is sufficiently smaller than the first term of equation (3b) (i.e., n×Ht). Furthermore, the second term of equation (3a) and the second term of equation (3b) are not significantly different. For these reasons, the second term of equation (3a) and the second term of equation (3b) can be ignored in the above inequality (3). In other words, there is no need to take into consideration the case where overlapping portions exist between jig-attached canned products 1 when stacked, or the case where overlapping portions exist between canned products 20 when stacked.

[0067] 1-3. Use of microwave heating tools 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.

[0068] 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.

[0069] 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. 6 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.

[0070] 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.

[0071] The microwave heating jig 10 shown in Figures 1 to 3 may be used in a so-called turntable-type microwave oven that has a turntable. Furthermore, the microwave heating jig 10 shown in Figures 1 to 3 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.

[0072] 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.

[0073] Figure 7 shows one embodiment in which the microwave heating jig 10 described with reference to Figures 1 to 3 is used to heat canned product 20 in the microwave oven 100 described with reference to Figure 6. Figure 7 depicts only the bottom plate 112 of the microwave oven 100, the upper surface of which is the interior bottom surface W1. The canned product 20 shown in Figure 7 is obtained by removing the portion of the can lid body 21c1 surrounded by the scores together with the pull-tab 21c2 from the canned product 20 described with reference to Figure 4 by pulling the pull-tab 21c2, thereby turning the can lid body 21c1 into a can lid body 21c1' that is open in the center.

[0074] When heating the item 22 in the metal can container 21 in the microwave oven 100, first, as shown in Fig. 7, the microwave heating jig 10 is attached to the bottom end of the open canned product 20. Specifically, the bottom end of the canned product 20 is inserted into the open end of the microwave heating jig 10, and the canned product 20 is placed on the protrusion P of the microwave heating jig 10.

[0075] FIG. 7 shows a metal can container 21 in which the outer diameter of the double-seamed portion at the top end is larger than the outer diameter of the double-seamed portion at the bottom end. In this case, if the top end of the canned product 20 can be inserted into the open end of the microwave heating jig 10, the bottom end of the canned product 20 can also be inserted into the open end of the microwave heating jig 10. On the other hand, the metal can container 21 may have an outer diameter at the double-seamed portion at the top end that is smaller than the outer diameter of the double-seamed portion at the bottom end. In this case, even if the top end of the canned product 20 can be inserted into the open end of the microwave heating jig 10, the bottom end of the canned product 20 may not be inserted into the open end of the microwave heating jig 10. In such cases, the microwave heating jig 10 shown in FIG. 7 may be turned upside down, with the reinforcing member 12 positioned above the support member 11, and the canned product 20 placed on the reinforcing member 12.

[0076] Also, here, the canned product 20 is opened before the microwave heating jig 10 is attached to the lower end of the canned product 20, but the canned product 20 may also be opened after the microwave heating jig 10 is attached to the lower end of the canned product 20.

[0077] Next, as shown in Figure 7, canned product 20 with microwave heating jig 10 attached to its lower end is placed on interior bottom surface W1 of microwave oven 100 so that lower portion 11b is positioned below canned product 20. Canned product 20 is preferably placed approximately in the center of interior bottom surface W1.

[0078] 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 upper surface of the protrusion P compared to when the canned products 20 are placed on the interior bottom surface W1 without the microwave oven heating jig 10.

[0079] 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 20 is open, microwaves can be incident on the item 22. Therefore, the item 22 is heated.

[0080] In the above method, the microwave heating jig 10 is attached to the bottom end of the canned product 20, 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 between them, making it less likely for sparks to 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.

[0081] Furthermore, microwave heating jig 10 can be used as an aid for removing heated canned products 20 from the interior of the oven. That is, when removing heated canned products 20 from the oven, microwave heating jig 10 attached to the bottom end of canned products 20 is manually carried to the outside of the oven, whereby canned products 20 and microwave heating jig 10 can be removed from the oven without coming into contact with canned products 20, which are at a higher temperature than microwave heating jig 10.

[0082] Furthermore, when the canned product 20 is unopened, the top surface of the canned product 20 can be protected from dirt and the like by attaching the microwave heating jig 10 to the top end of the canned product 20 as shown in Fig. 4. Also, when an opened canned product 20 is stored, attaching the microwave heating jig 10 to the top end of the canned product 20 makes it less likely that foreign matter will get mixed into the item 22 contained in the metal can container 21 or that liquid components contained in the item 22 will evaporate.

[0083] The microwave heating jig 10 also has a recess R on the ridge 13. A microwave heating jig 10 with this structure further achieves the following advantages. Specifically, jig-attached canned products 1 are typically transported in multiple stacked rows and columns. For example, a packaged product in which multiple jig-attached canned products 1 are arranged vertically and horizontally and stacked in multiple layers is transported. Alternatively, a packaged product in which multiple jig-attached canned products 1 are arranged vertically and horizontally and stacked in multiple layers on a pallet and integrated with a film or sheet is transported. The microwave heating jig 10 may be subjected to a large force in its vertical direction due to vibrations and other factors during transport of the packaged product. The recess R reduces the risk of damage to the microwave heating jig 10 caused by such force.

[0084] When the microwave oven heating jig 10 is made of a material having the above-mentioned relative permittivity and dielectric loss tangent, it further exhibits the effects described below.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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 10.

[0090] Therefore, when heating an item 22 contained in a metal can container 21 in a microwave oven 100, by using a microwave heating jig 10 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.

[0091] 1-4. Variations The microwave heating jig and the canned product with the jig can be modified in many ways. As described above, the metal can container 21 included in the canned product 20 to be combined with the microwave heating jig 10 may be either a three-piece can or a two-piece can. Furthermore, as described above, the outer diameter of the double seamed portion at the upper end of the metal can container 21 may be larger than the outer diameter of the double seamed portion at the lower end, or the outer diameter of the double seamed portion at the upper end may be smaller than the outer diameter of the double seamed portion at the lower end.

[0092] The microwave heating jig 10 has a circular shape when orthogonally projected onto a plane perpendicular to its height direction. The microwave heating jig does not have to have a circular shape when orthogonally projected onto a plane perpendicular to its height direction. For example, the microwave heating jig may have a square, rectangle, square with rounded corners, or rectangle with rounded corners when orthogonally projected onto a plane perpendicular to its height direction.

[0093] 2.Packaged goods A plurality of the jig-attached canned products 1 described above can be packed or wrapped in a packaging material to form a packaged article. Specifically, the packaged article comprises a plurality of jig-attached canned products 1 stacked vertically and a packaging material that contains or holds together the plurality of jig-attached canned products 1. In the packaged article, for example, 2 to 5 jig-attached canned products 1 are stacked. Examples of the packaging material include a box, a film, or a sheet.

[0094] The jig-attached canned products 1 described above are usually transported in a state where multiple products are arranged lengthwise and widthwise and stacked in multiple layers. Therefore, an example of a packaged product is a packaged product in which multiple jig-attached canned products 1 are arranged lengthwise and widthwise and stacked in multiple layers inside a box. Another example is a packaged product in which multiple jig-attached canned products 1 are arranged lengthwise and widthwise and stacked in multiple layers on a pallet and integrated with a film or sheet.

[0095] Furthermore, the jig-attached canned products 1 described above are sold, for example, stacked vertically and integrated with a film or sheet. Therefore, another example of a packaged product is a packaged product formed by stacking multiple jig-attached canned products 1 vertically and integrating them with a film or sheet.

[0096] As explained above, the jig-attached canned products 1 included in the package satisfy the relationship shown in inequality (1) above, where the height Ht of the jig-attached canned products 1 and the height Hk of the canned products 20. That is, the total height THt of n stacked jig-attached canned products 1 (n is an integer between 2 and 5) is within the range of the total height THk of the (n+1) stacked canned products 20 ±10%. Therefore, the package can achieve the same effects as those explained above for the jig-attached canned products 1.

[0097] As described above, the jig-attached canned products 1 included in the package preferably have a larger inner diameter at the bottom of the metal can container 21, i.e., the inner diameter of the double-seamed portion at the bottom, than the outer diameter at the end of the microwave heating jig 10 near the reinforcing portion 12. When such jig-attached canned products 1 are stacked vertically to form a package, the end of the lower jig-attached canned product 1 near the reinforcing portion 12 of the microwave heating jig 10 is located within the area surrounded by the double-seamed portion at the bottom of the metal can container 21 of the upper jig-attached canned product 1, as shown in FIG. 5(b). In this case, the stacked state of the jig-attached canned products 1 is stable, facilitating the packing and wrapping operations for producing the packaged product, and the stacked state can be maintained during distribution even when packed in a box. Furthermore, in this case, if the jig-attached canned products 1 are removed from the packaging in the stacked state, the multiple jig-attached canned products 1 can be handled as a single assembly.

[0098] 3. Jig-attached canned product kit The microwave heating jig 10 described above can also be combined with metal can containers 21 that do not contain an item 22 and distributed as a kit for jig-attached canned products. In order to achieve the same effects as those described above for the jig-attached canned products 1 in the kit for jig-attached canned products, it is preferable that the number of microwave heating jigs 10 and the number of metal can containers 21 match.

[0099] This kit includes the metal can container 21 described above and the microwave heating jig 10 described above. In this kit, the metal can container 21 does not contain an item 22. A manufacturer that produces items to be contained in metal can containers can obtain this kit, fill the container body of the metal can container 21 with the item 22, seal it with a lid, produce a canned product 20, and arrange the obtained canned product 20 and the microwave heating jig 10 so that they are aligned in the height direction, thereby producing a jig-attached canned product 1. [Example]

[0100] The following describes tests carried out in connection with the present invention.

[0101] <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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] [Table 1]

[0107] 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.

[0108] 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.

[0109] <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.

[0110] 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.

[0111] 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.

[0112] [Table 2]

[0113] The evaluation criteria for "burnt / melted state" in Table 2 are the same as the evaluation criteria for "burnt / melted state" in Table 1.

[0114] 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.

[0115] 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]

[0116] 1...canned product with jig, 10...microwave heating jig, 11...support part, 11b...lower part, 11m...middle part, 11p...projecting part, 11t...upper part, 12...reinforcing part, 13...ridge part, 20...canned product, 21...metal can container, 21a...can body, 21b...can bottom, 21c...can lid, 21c1...can lid main body, 21c1'...can lid main body, 21c2...pull tab, 22...item, 22a...first food, 22b...second food, 100...electricity Sub-microwave, 110...microwave oven body, 111...cover body, 112...bottom plate, 120...door, dH1...height of overlapping part between canned products, dH2...height of overlapping part between canned products attached with jig, Hk...height of canned products, Ht...height of canned products attached with jig, THk...total height of canned products, THt...total height of canned products attached with jig, P...convex part, R...concave part, W1...bottom surface of interior, W2...side surface of interior, W3...side surface of interior.

Claims

1. A canned product including a metal can container and an item contained therein; a non-metallic microwave heating tool used to place the metal can container in the microwave oven with a wider distance from the bottom of the microwave oven when heating the item contained in the metal can container in the microwave oven; The canned product and the microwave heating jig are arranged so as to be aligned in the height direction of the canned product, The height Ht of the canned product attached to the jig and the height Hk of the canned product are expressed by the following inequality (1): 0.9×(n+1)×Hk≦n×Ht≦1.1×(n+1)×Hk (where n represents an integer ranging from 2 to 5).

2. The microwave oven heating jig 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 2. The jig-attached canned product of claim 1, which is made of the following materials:

3. The canned food product with a jig according to claim 1, wherein the microwave oven heating jig is made of a cured resin.

4. 2. The canned food product with a jig according to claim 1, wherein the microwave oven heating jig has a generally cylindrical shape and is attached to the upper end of the canned food product.

5. A packaged article comprising a plurality of jig-attached canned products stacked vertically and a packaging material containing or holding together the plurality of jig-attached canned products, each of the plurality of jig-attached canned products being a jig-attached canned product described in any one of claims 1 to 4.

6. The device comprises a metal can container for storing microwave-heatable items and a non-metallic microwave heating jig, When a canned product including the article and the metal can container containing the article, and the jig-attached canned product including the microwave heating jig, are distributed, the microwave heating jig is arranged so as to be aligned with the canned product in the height direction of the canned product, and when the article contained in the metal can container is heated in a microwave oven, the metal can container is placed in the microwave oven with its distance from the bottom surface of the microwave oven increased, The height Ht of the canned product attached to the jig and the height Hk of the canned product are expressed by the following inequality (1): 0.9×(n+1)×Hk≦n×Ht≦1.1×(n+1)×Hk (where n represents an integer ranging from 2 to 5)

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