CN115768701A

CN115768701A - Container for microwave oven

Info

Publication number: CN115768701A
Application number: CN202180042596.XA
Authority: CN
Inventors: 片山亮
Original assignee: Kyoraku Co Ltd
Current assignee: Kyoraku Co Ltd
Priority date: 2020-06-30
Filing date: 2021-06-24
Publication date: 2023-03-07
Also published as: JP2022012044A; WO2022004543A1

Abstract

The invention provides a microwave oven container which does not cause deformation of the container after steam is discharged. According to the present invention, there is provided a container for a microwave oven, comprising a film-like lid portion; a container body having an opening at an upper portion thereof, formed in a concave shape, and capable of storing contents; and a flange portion formed to extend outward from the opening, wherein a welding portion welded to a back surface of the lid portion is formed on an upper surface of the flange portion, the welding portion includes a steam discharge portion for discharging steam generated inside the container body, and the lid portion is formed of a shrink film.

Description

Container for microwave oven

Technical Field

The present invention relates to a container for microwave oven.

Background

A container for a microwave oven has a flange portion extending outward from an opening as disclosed in, for example, patent document 1 below, and a rib-like heat-fusion portion is formed over the entire periphery of the upper surface of the flange portion. The heat-fusion part is a part for heat-fusing the film cover part for covering the opening of the container. In addition, a steam discharge portion for so-called steam discharge is formed in a part of the heat fusion portion, and the steam discharge portion is formed of a V-shaped portion having a pattern which is opened outward. In the steam discharge portion having such a structure, when the steam generated in the container reaches a predetermined pressure, stress is concentrated on the sharp portion inside the V-shaped portion, and the thermal welding of the lid portion is broken.

However, in the steam discharge portion configured as described above, the discharged steam becomes water, and the cover comes into close contact with the steam discharge portion, thereby causing a phenomenon in which the steam discharge port is blocked. At this time, the inside of the container is depressurized as the container is cooled, which causes a problem that the container is deformed.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2008-290738

Disclosure of Invention

(problems to be solved by the invention)

The present invention has been made in view of the above circumstances, and an object thereof is to provide a container for a microwave oven that does not cause deformation of the container after steam is discharged.

(means for solving the problems)

According to the present invention, there is provided a container for a microwave oven, comprising a film-like lid portion; a container body having an opening at an upper portion thereof, formed in a concave shape, and capable of storing contents; and a flange portion formed to extend outward from the opening, wherein a welded portion welded to a back surface of the lid portion is formed on an upper surface of the flange portion, the welded portion includes a steam discharge portion for discharging steam generated inside the container body, and the lid portion is formed of a shrink film.

Since the lid portion is formed of a shrink film, the container is heated and shrunk, and therefore, the lid portion is rolled up in the vicinity of the steam outlet port, and does not block the steam outlet port. Thus, the inside of the container is not decompressed when the container is cooled, and thus deformation of the container can be prevented.

Preferably, the flange portion is formed over a periphery of the container main body, and the steam discharging portion is formed at a corner portion of the periphery.

Preferably, the welded portion is formed in a rib shape protruding from an upper surface side of the flange portion.

Drawings

Fig. 1 is a perspective view showing the entire container 1 for a microwave oven according to embodiment 1 of the present invention.

In fig. 2, fig. 2A is a plan view of the container body 2, and fig. 2B is a side view of the container body 2.

Fig. 3 is a sectional view taken along line III-III in fig. 2A.

In fig. 4, fig. 4A is a perspective view showing the lid unsealing portion 24 and the steam vent portion 25, and fig. 4B is a sectional view taken along the line IVb-IVb in fig. 4A.

Fig. 5 is a schematic view of the vicinity of the wide width part 22A immediately after heating with a microwave oven.

Fig. 6 is a view corresponding to fig. 3 of a container 1 for a microwave oven according to embodiment 2.

Fig. 7A is a view corresponding to fig. 4A of a container 1 for a microwave oven according to embodiment 2, and fig. 7B is a cross-sectional view taken along line VIIb-VIIb in fig. 7A.

Fig. 8 is a plan view of a container 1 for a microwave oven according to embodiment 3.

Fig. 9 is a schematic view showing an example of the microwave oven immediately after the container 1 for a microwave oven in embodiment 3 is heated by the microwave oven.

Fig. 10A is a plan view of the container body 2 according to embodiment 4, and fig. 10B is a sectional view taken along Xb-Xb in fig. 10A.

In fig. 11, fig. 11A is a plan view of the seal bar 30, and fig. 11B is an enlarged view of a region D in fig. 11A.

Detailed Description

Embodiments of the present invention will be described below. Various feature items shown in the embodiments shown below may be combined with each other. In addition, each feature may independently constitute the invention.

<1. Embodiment 1 >

Fig. 1 is a perspective view showing the entire container for a microwave oven according to the present invention. A container 1 for a microwave oven shown in fig. 1 is composed of a container main body 2 and a lid 3.

The container body 2 is formed of, for example, 1 or more layers of resin materials containing polypropylene or the like, has a substantially rectangular shape with rounded corners in plan view, has an opening 21 at the top, is formed in a concave shape, and can store contents. The container body 2 has a flange 22 extending outward from the opening 21. The flange portion 22 is substantially rectangular in plan view, and the corner portion has a wide portion 22A having a width wider than the other portion. The plan view is a view of the microwave oven container 1 viewed from above in the vertical direction.

The flange portion 22 is formed with a rib-like heat fusion bonding portion 23 projecting on the upper surface side thereof. The heat-fusion portion 23 is formed over the entire periphery of the flange portion 22. In other words, the heat fusion part 23 is formed on the upper surface of the flange part 22 so as to surround the opening 21 of the container body 2.

The cover portion 3 is a film having an outer periphery of substantially the same size as the outer periphery of the flange portion 22, and includes a base material layer and a sealant layer. The base material layer is composed of a shrink film (heat shrinkable film). The shrink film is a resin film having heat shrinkability obtained by stretching (uniaxial stretching or biaxial stretching), and examples of the material include polyester resins such as polyethylene terephthalate, polyamide resins such as nylon 6, and olefin resins such as polyethylene and polypropylene. The cover 3 may be formed by laminating an outer layer such as a printed layer on the outer side of the base material layer.

The sealant layer may be formed of a polyolefin resin such as polyethylene, polypropylene, an ethylene-vinyl acetate copolymer, and an ethylene-propylene block copolymer, and more specifically, non-oriented polypropylene or linear low-density polyethylene may be used. More preferably, the easy-peel sealant is obtained by mixing polyethylene and polypropylene in a predetermined ratio. This facilitates the peeling of the lid 3 from the container body 2.

Here, the peel strength can also be adjusted by changing the ratio of the mixed resins. For example, when the container body 2 is made of polypropylene, the adhesive strength can be improved by increasing the proportion of polypropylene contained in the mixed resin, and the peelability can be improved by decreasing the proportion.

The lid portion 3 is configured to receive contents (not shown) in the container body 2 and then thermally weld (seal) the contents to the thermally welded portion 23 to close the opening 21 of the container body 2. Fig. 1 shows a state where the cover portion 3 is partially peeled off from one wide portion 22A of the flange portion 22.

Further, a steam discharge portion 25 in which the heat-fused portion 23 is formed in an M-shaped pattern is formed in the wide portion 22A of the flange portion 22 which is a starting point of the peeling of the lid portion 3.

Fig. 2A is a plan view of the container body 2, and fig. 2B is a side view of the container body 2. As shown in fig. 2A, the M-shaped steam discharging portion 25 formed as a part of the heat-fusion bonded portion 23 has a V-shaped pattern (V-shaped portion extending outward) formed at the center thereof, and the inverted V-shaped patterns (V-shaped portion extending inward) on both sides thereof form the lid opening portion 24. The right side portion of the steam discharging portion 25 is formed integrally with a portion adjacent to the right lid opening portion 24, and the left side portion of the steam discharging portion 25 is formed integrally with a portion adjacent to the left lid opening portion 24.

When the lid portion 3 is peeled off from the wide portion 22A of the flange portion 22 where the lid opening seal portion 24 is formed, stress is concentrated on the sharp portion of the inverted 'V' shaped pattern of the lid opening seal portion 24, and an effect of easily peeling off the lid portion 3 is obtained. Further, when the container body 2 is heated in the microwave oven, stress of the steam pressure generated in the container body 2 is concentrated on the sharp part of the V-shaped pattern of the steam discharging part 25, and when the steam pressure reaches a predetermined pressure, the effect of easily breaking the thermal welding with the lid part 3 is obtained.

Fig. 3 is a sectional view taken along line III-III of fig. 2A. As shown in fig. 3, the heat-fusion part 23 is formed substantially horizontal to the upper surface thereof, and the reliability of heat fusion with the cover part 3 can be ensured. The heat-fusion bonded portion 23 is formed such that the height t2 of the inner peripheral side with respect to the flange portion 22 is lower than the height t1 of the outer peripheral side with respect to the flange portion 22.

A side surface of the container body 2 is formed with a step 27 having a diameter decreasing downward along the circumference thereof. The side surface 28 on the opening 21 side of the step 27 is inclined outward with respect to the vertical direction (indicated by a broken line P in the drawing). Such a step 27 on the side surface of the container body 2 has a function as a stopper when stacking a plurality of container bodies 2, and prevents the upper container body 2 from being accommodated deep in the lower container body 2, and by inclining the side surface 28 closer to the opening 21 side than the step 27 outward in the vertical direction, it is possible to easily pull out the upper container body 2 from the lower container body 2.

Fig. 4A is a perspective view showing the cover opening part 24 and the steam discharging part 25 formed in the wide part 22A of the flange part 22. FIG. 4B is a sectional view taken along line IVb-IVb of FIG. 4A. As shown in fig. 4B, the steam discharge portion 25 is inclined such that the front end located inside the V-shaped portion becomes lower toward the opening.

By inclining the steam discharging portion 25 so that the tip located inside the V-shaped portion is lowered toward the opening 21 in this manner, the sealing strength of the steam discharging portion 25 on the opening 21 side can be weakened, and the effect of easily releasing steam can be achieved. It is therefore possible to control to reliably break the thermal welding of the lid portion 3 when the steam reaches the prescribed pressure.

Here, a preferable mode in the case where the steam discharging portion 25 is inclined such that the tip located inside the V-shaped portion becomes lower toward the opening 21 will be described. In fig. 4B, in view of securing the thickness of the member to be provided as the container for the microwave oven, the height t7 from the flange 22 of the outer edge of the end portion (left end in the drawing) on the expansion side of the steam discharging part 25 is preferably 1mm to 5mm, and more preferably 1mm to 3mm. More specifically, the height t7 may be any of 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, or may be a value within these numerical ranges, and may be, for example, 1.37mm.

The height t8 of the heat fusion portion 23 connected to the lid opening seal portion 24 from the flange portion 22 is set to be higher than the height t7 of the left end outer edge. The height t8 may be set to be 0.1mm to 1.0mm higher than the height t7, and may be 1.5mm, for example.

The height t6 of the right end outer edge is preferably equivalent to 40% to 90% of the height t7 of the left end outer edge. The height t5 of the right inner edge is preferably 5% to 60% of the height t7, and may be 0.8mm, for example. The height t5 is more preferably lower than the height t6.

Further, the difference (t 8-t 7) between the height t8 of the heat-fused portion 23 from the flange portion 22 and the height t7 of the left-end outer edge from the flange portion 22 is preferably smaller than the difference (t 7-t 5) between the height t7 of the left-end outer edge and the height t5 of the right-end inner edge.

Thus, by making the V-shaped tip of the steam vent 25 lower than the expanded end and making the inner edge of the tip itself lower than the outer edge, the steam vent 25 changes from a portion where the sealing strength is relatively strong to a portion where the strength is weak from the side away from the opening 21 of the container body 2 to the side close to the opening 21.

Fig. 5 is a schematic view showing the vicinity of the wide part 22A immediately after heating in the microwave oven. As described above, in the container 1 for a microwave oven, since the lid portion 3 is formed of a shrink film, when steam generated in the container by heating is discharged, the lid portion 3 shrinks and curls upward. This prevents the lid 3 from blocking the steam discharge portion 25, and prevents deformation of the container due to depressurization inside the container. Further, since the central portion of the cover part 3 shrinks after heating, wrinkles and sagging of the cover part 3 can be eliminated, and the appearance is better. Here, by forming the steam discharging portion 25 at the corner portion around the container main body 2, the container main body 2 is also pulled and warped by the lid portion 3. Therefore, the angle of the V-shaped portion of the steam discharging portion 25 becomes steep, and the steam discharging portion 25 is not easily blocked. Further, the steam outlet 25 and the lid opening 24 are formed in a rib shape protruding from the upper surface of the flange 22, so that the container main body 2 is warped to facilitate formation of the steam outlet.

<2 > embodiment 2 >

The container 1 for a microwave oven according to embodiment 2 is different from embodiment 1 in that a flange portion 22 of a container body 2 is formed obliquely. The following description will focus on different points.

As shown in fig. 6, the flange portion 22 of the container body 2 is formed such that its extending end is inclined downward at an angle θ (for example, 6 ° to 10 °). Such inclination of the flange portion 22 is substantially the same over the entire circumference of the flange portion 22.

As shown in fig. 7B, the flange portion 22 is formed such that the extended end thereof is inclined downward at an angle θ, and thus a height t3 of the inside of the steam discharge portion 25 with respect to the horizontal plane Q is lower than a height t4 of the outside with respect to the horizontal plane Q. At this time, the upper surface of the heat fusion bonded part 23 other than the steam discharging part 25 is formed to be horizontal.

In fig. 7B, in view of securing the thickness of the member to be provided as the container for microwave oven, the height t7 of the outer edge of the end portion (left end in the drawing) on the expansion side of the steam discharging portion 25 from the flange portion 22 is preferably set to 1mm to 5mm, and more preferably set to 1mm to 3mm. More specifically, the height t7 is any value of 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, or may be a value within these numerical ranges, and may be, for example, 1.2mm.

The height t6 of the right end outer edge preferably corresponds to 40% to 90% of the height t7 of the left end outer edge. The height t5 of the right inner edge is preferably 5% to 50% of the height t7. Further, the height t5 is more preferably lower than the height t6. The length t9 from the right end inner edge of the steam discharge portion 25 to the end of the opening 21 is preferably within 10mm, preferably within 5mm, more preferably 0mm, and may be any value of 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0mm, or may be a value within these numerical ranges (the same as in embodiment 1). The container 1 for a microwave oven provided with the flange portion 22 of this embodiment can also obtain the same effects as those of embodiment 1.

<3 > embodiment 3 >

In the above embodiment, the container body 2 of the container 1 for a microwave oven is formed in a substantially rectangular shape having a circular arc at a corner portion in a plan view, and the corner portion has the wide portion 22A. However, the present invention is not limited to this embodiment. For example, as shown in fig. 8, the container body 2 may be formed in a substantially elliptical shape in plan view, and may have 1 pair of wide portions 22A and steam discharge portions 25 at both ends in the longitudinal direction. At this time, although the steam is basically discharged from either of the steam discharge portions 25, the steam may be discharged from both ends in the longitudinal direction as shown in fig. 9 depending on the amount of the steam and the size of the steam port, and the lid portion 3 may warp upward.

<4 > embodiment 4 >

In the above embodiment, the flange portion 22 of the container main body 2 is formed with the rib-shaped heat fusion bonding portion 23 which is convex, but the flange portion 22 is formed flat in the 4 th embodiment, which is different from the above embodiment. The following description will focus on different points.

As shown in fig. 10A and 10B, in the container main body 2 according to embodiment 4, the flange portion 22 is formed flat, and the flange portion 22 includes the heat-fusion portion 23. The sealing rod 30 that thermally welds the container body 2 and the lid 3 is formed with a projection 31 for forming the thermal weld 23 on the flat flange 22. In the present embodiment, the pressure at the time of heat welding is increased by the convex portion 31 formed on the seal rod 30, thereby forming the heat-welded portion 23.

As shown in fig. 11A and 11B, the convex portion 31 is formed in a ring shape on the seal rod 30 so as to face the flange portion 22 of the container body 2 when the container body 2 and the lid portion 3 are thermally welded. An opening portion forming portion 32A for forming the lid opening portion 24 and a discharge portion forming portion 32B for forming the steam discharge portion 25 are formed at positions facing the wide portion 22A of the container body 2.

The height T11 of the easy-to-open portion forming portion 32A is higher than the height T12 of the steam discharging portion 25. With this configuration, the pressure applied to the flat flange portion 22 by the opening portion forming portion 32A during heat welding can be made larger than the pressure applied to the discharge portion forming portion 32B. This can make the sealing strength of the steam outlet 25 weaker than that of the lid opening portion 24, and can provide an effect of facilitating the release of steam.

In the container 1 for a microwave oven having such a configuration, the same effects as those of the above-described embodiment can be obtained by forming the lid portion 3 of a shrink film.

<5 > other embodiments

The embodiments have been described above, but the technical idea of the present invention can be applied to the following embodiments.

In the above embodiment, the height t7 of the expanded side of the steam discharge portion 25 from the flange portion 22 is different from the height t6 of the opposite side thereof, but the present invention is not limited to this embodiment. The height from the flange portion 22 in the steam discharging portion 25 (and the integrally formed lid opening portion 24) can be made constant.

In the above embodiment, the steam discharge portion 25 is formed in the shape of an 'M', but is not limited to this shape.

In the above embodiment, the cover opening part 24 is formed integrally with the steam discharging part 25, but the present invention is not limited to this embodiment and may be provided separately.

The number of steam discharge portions is not limited to the above embodiment.

(symbol description)

1: container for microwave oven, 2: container body, 3: lid portion, 21: opening, 22: flange portion, 22A: wide part, 23: heat fusion part, 24: lid opening portion, 25: steam discharge unit, 27: step, 28: side surface, 30: sealing rod, 31: convex portion, 32A: opening portion forming portion, 32B: a discharge portion forming portion.

Claims

1. A container for a microwave oven, comprising:

a film-like cover portion;

a container body having an opening at an upper portion thereof, formed in a concave shape, and capable of accommodating contents; and

a flange portion formed to extend outward from the opening,

a welding part welded with the back surface of the cover part is formed on the upper surface of the flange part,

the welding part comprises a steam discharging part for discharging the steam generated in the container main body,

the cover portion is constituted by a shrink film.

2. The container for a microwave oven as claimed in claim 1, wherein,

the flange portion is formed over the circumference of the container body,

the steam discharge portion is formed at a corner of the periphery.

3. The container for a microwave oven according to claim 1 or 2, wherein,

the weld portion is formed in a protruding rib shape on an upper surface side of the flange portion.