JP7637588B2 - Container and method for discharging steam from container - Google Patents

Description

The present invention relates to a container for storing food, a container, and a method for venting steam from a container, and in particular to a container that can be used for cooking in a microwave oven or the like with the lid closed.

Some containers for storing food and the like have a function for exhausting steam generated during cooking in a microwave oven or the like. Some containers that can exhaust steam have a steam hole such as a valve punched into a U-shape or C-shape on the top surface of the lid to prevent the lid from flying off due to the internal pressure of the container and the loss of rigidity of the container material when heated (see, for example, Patent Document 1). Others have side air that promotes exhaust by providing a protrusion on the side wall of the lid (see, for example, Patent Document 2).

Another type of container that can exhaust steam has a recess or curved portion on the top surface of the lid, and a slit or cut (slit valve) is provided in the recess or curved portion, and when the container is heated and internal pressure is applied, the slit valve opens to exhaust steam (see, for example, Patent Documents 3 to 6). Another type of container has a large number of fine holes formed by laser irradiation, and exhausts steam through the fine holes (see, for example, Patent Document 7).

In configurations where exhaust ports such as steam holes, side air, and fine holes are provided, as in the containers of Patent Documents 1, 2, and 7, it is expected that the size and number of the exhaust ports will have an effect of suppressing the intrusion of foreign matter such as insects and dust, but these cannot be completely prevented. In configurations where exhaust ports are provided using slit valves, as in the containers of Patent Documents 3 to 6, the slit valve opens when the exhaust port is closed due to the pressure inside the container when heated, and although it is possible to prevent the intrusion of foreign matter if the exhaust port can be kept completely closed, it is not a panacea, as gaps can easily be created by external pressure. In addition, there is a method of improving the above problem by attaching low-adhesion labels or cut-out labels to the steam holes and slit valves, but this increases costs and labor, which is a problem.

In addition, in order to prevent foreign matter from entering the container, there is another container in which no holes for discharging steam are provided on the top surface of the lid, and the lid flange part softened by the steam generated by heating rises from the upper surface of the main body flange part to exhaust steam (see, for example, Patent Document 8). Specifically, the container in Patent Document 8 has multiple communication grooves on the outer surface of the lid inner fitting surface part as a passage for steam, and in the closed state, only the annular downward ridge provided on the lid flange part abuts on the upper surface of the main body flange part. The container has an annular inner separation space part formed by the lid flange part, the main body flange part, and the downward ridge inside the downward ridge. When heated, steam enters the communication groove and fills the inner separation space part. The lid flange part is heated by this filling steam, and the resin of the lid flange part softens. The lid flange part easily rises upward due to the softening of the resin, and a gap is formed between the downward ridge and the upper surface of the main body flange part, and the steam is exhausted from the gap to the outside.

In the container of Patent Document 8, if the steam generated by a sudden rise in the internal pressure of the container due to heating in a high-power microwave oven or the like enters the communication groove all at once, there is a risk that the lid flange will not rise in time and the steam will leak out all at once.

Another type of container has a groove for discharging steam formed on the outer periphery of the lid or on the fitting part of the container body, and the lid is pushed up by an increase in the internal pressure of the container to open the blocked groove portion, and steam is discharged from the opened groove portion (see, for example, Patent Documents 9 to 11). The containers in Patent Documents 9 to 11 can also have the same problems as Patent Document 8. In addition, the container in Patent Document 11 cannot be used for shrink packaging, etc., because the lid moves upward to form an exhaust portion.

JP 2007-191161 A JP 2010-58809 A JP 2019-167158 A Registered Utility Model No. 3220615 JP 2019-81612 A JP 2019-147574 A JP 2018-20851 A JP 2020-132240 A JP 2001-80682 A Japanese Patent Application Publication No. 10-316177 JP 2010-215259 A

The present invention has been made in consideration of the above-mentioned background technology, and aims to provide a container and a method for venting steam from a container that allows steam to be vented without coming off the container during cooking in a microwave oven or the like, even if the container has a configuration that does not have holes.

A container lid for achieving the above-mentioned object is a container lid having a top surface portion covering an opening of a container body that contains food, and a lid edge portion that is removably fixed to the body edge portion of the container body, wherein the top surface portion has a deformation portion that promotes local deformation due to internal pressure when heated, and the lid edge portion has a fitting portion that fits into the body edge portion and one or more steam exhaust portions arranged between the fitting portions, and the steam exhaust portions protrude above the deformation portion, and the steam exhaust portions are displaced upward as the deformation portion deforms, and have a partition portion that faces the inner surface of the container body and includes an opposing surface that extends in contact with the inner surface of the container body.

With the above-mentioned container lid, the top surface has a deformation portion that can deform when heated, which makes it possible to gently increase the internal pressure inside the container when heated. In addition, the lid edge has a steam exhaust portion, and the steam exhaust portion has a partition portion, which makes it possible to prevent the intrusion of foreign matter such as insects and dust. The steam exhaust portion opens as the deformation portion deforms, and exhausts steam.

In a specific embodiment of the present invention, the steam exhaust section of the container lid has an inner wall including an opposing surface, an outer wall disposed on the opposite side of the inner wall across the body edge, and a top connecting the upper parts of the inner wall and the outer wall, and the top is inclined upward from the inner wall toward the outer wall. In this case, during heating, while maintaining the engagement by the engagement section, the steam exhaust section deforms and displaces with the deformation of the deformation section, making it easier to form a gap for exhaust at the position of the steam exhaust section on the outer edge of the container. This makes it possible to maintain the exhaust function without the lid coming off the container even in the case of high-output and long-term cooking. In addition, the upward inclination of the steam exhaust section can prevent the shrink film from suppressing deformation of the steam exhaust section in a container wrapped in shrink film. In other words, it prevents the shrink film, etc. from blocking the appearance of an exhaust port for steam exhaust.

In another aspect of the present invention, the inner wall extends in contact with or adjacent to the inner surface of the container body, and the outer wall has a gap between it and the edge of the body. In this case, it is possible to easily form a gap between the steam exhaust section and the container body during heating.

In yet another aspect of the present invention, the partition has an exhaust port forming portion that is deformed in accordance with the deformation of the deformation portion. In this case, the exhaust port forming portion forms an exhaust port between the steam exhaust portion and the edge of the main body by the steam exhaust portion deforming or displacing due to the internal pressure and temperature rise of the container when heated. The exhaust port also appears when the lid is fixed with a shrink film, a ribbon label, or the like.

In yet another aspect of the present invention, the opposing surface is inclined with respect to the axis of symmetry of the container body. In this case, the displacement of the steam exhaust section can be further promoted, and the formation of an exhaust port or gap can be ensured.

In yet another aspect of the present invention, the top surface, in a cross-sectional view including the axis of symmetry of the container body, is inclined radially outward from the center downward from the axis of symmetry of the container body, and then inclined upward. In this case, when the top surface deforms in response to an increase in internal pressure within the container during heating, a partial rise occurs, widening the space, making it easier to store steam and further suppressing an increase in internal pressure within the container.

In yet another aspect of the present invention, the top surface has a support portion closer to the center than the deformation portion, and the deformation portion is curved and inclined in a direction from below to above the axis of symmetry from the outer edge of the support portion toward the lid edge portion in a cross-sectional view. In this case, by providing the support portion, the inclination change from below to above the entire top surface can be increased, and the deformation area of the top surface when heated can be expanded to the outside of not only the deformation portion but also the support portion. Furthermore, by providing the support portion, it is possible to prevent the shrink film from suppressing deformation of the steam exhaust portion in a container wrapped in shrink film.

In yet another aspect of the present invention, the deformation portion is either a curved portion or a bent portion. In this case, the top surface portion can be easily deformed.

In order to achieve the above object, the method of discharging steam from a container according to the present invention is a method of discharging steam from a container comprising a container body for storing food, a top surface covering an opening of the container body, and a lid having a lid edge portion removably fixed to the body edge portion of the container body, in which the top surface has a deformation portion that promotes local deformation due to internal pressure when heated, the lid edge portion has a fitting portion that fits into the body edge portion and one or more steam discharge portions arranged between the fitting portions, the steam discharge portions protrude above the deformation portion, the steam discharge portions are displaced upward as the deformation portion deforms, and have a partition portion that faces the inner surface of the container body and includes an opposing surface that extends in contact with the inner surface of the container body, and as the deformation portion deforms when heated, the partition portion separates from the inner surface of the container body to allow steam to be discharged, thereby discharging steam from inside the container.

According to the above-mentioned method for discharging steam from a container, the top surface has a deformable portion that can deform when heated, which makes it possible to gently increase the internal pressure inside the container when heated. In addition, the lid edge has a steam discharge portion, and the steam discharge portion has a partition portion, which makes it possible to prevent the intrusion of foreign matter such as insects and dust before heating.

1A and 1B are a conceptual plan view and a front view illustrating a container according to an embodiment. 1A is a cross-sectional view of the container shown in FIG. 1A, FIG. 1B is a cross-sectional view of the container lid, and FIG. 1C is a cross-sectional view of the container body. 1A to 1D are conceptual enlarged partial cross-sectional views illustrating the lid of the container shown in FIG. 1A, where (A) is an A-A cross-sectional view, (B) is a B-B cross-sectional view, (C) is a CC cross-sectional view, and (D) is a D-D cross-sectional view. (A) is a diagram showing the cross-sectional views of the lid shown in Figures 3(A) to 3(C) superimposed on each other, (B) is a conceptual cross-sectional view of the container when heated, (C) is a partially enlarged view of the side of the container including the steam exhaust portion of the lid, and (D) is an enlarged cross-sectional view of the steam exhaust portion. FIG. 13 is a conceptual diagram illustrating an example of stacking containers. FIG. 2A is a conceptual diagram showing the state of the container before cooking, and FIG. 2B is a conceptual diagram showing the state of the container during cooking. 13A and 13B are cross-sectional views illustrating a fitting portion of the lid. 1A to 1C are diagrams illustrating modified examples of the lid of the container shown in FIG.

[Embodiment]
Hereinafter, a container 100 with a lid 20 according to the present invention will be described with reference to Fig. 1(A) and other figures. The container 100 is for storing food or ingredients. The container 100 can be used for cooking food stored in the container body 10 in a microwave oven or the like with the lid 20 closed, i.e., in a closed lid state.

As shown in Figs. 1(A), 1(B) and 2(A), the container 100 includes a container body 10 and a lid 20. Figs. 1(B) and 2(A) show the container 100 in its entirety wrapped in a shrink film 30. The container 100 has various shapes in plan view, such as a circle, an ellipse, a rectangle, a polygon, etc. The container 100 in Fig. 1(A) etc. shows an example having a circular outer shape in plan view. Although not shown, when the container 100 has a rectangular or polygonal shape, the sides of the container 100 may be straight or curved. When the container 100 has a rectangular or polygonal shape, it is preferable that the corners of the container 100 are rounded. Below, an example in which the container 100 has a circular shape in plan view will be described.

As shown in Figs. 1(A), 1(B), 2(A), and 2(C), the container body 10 is a bowl-shaped vessel having an opening 11 on the upper side, and has a bottom surface portion 12, a body side surface portion 13, and a body edge portion 14. The bottom surface portion 12 has a substantially circular shape in a plan view. A leg portion 15 is provided at the lower part of the bottom surface portion 12. The leg portion 15 may be omitted. The body side surface portion 13 is cylindrical, and more specifically, has a tapered shape extending from the peripheral edge 12a of the bottom surface portion 12 so as to expand upward. The body edge portion 14 is provided so as to protrude outward from the upper end 13a of the body side surface portion 13. The body edge portion 14 is provided around the entire circumference of the opening 11 of the container body 10. The body edge portion 14 can be fitted into the fitting portion 23 of the lid edge portion 22 described later. The body edge portion 14 may be formed by curling the peripheral edge of the container body 10, or may be formed as a protrusion. The container body 10 is made of paper, resin, or the like. The material of the container body 10 has heat resistance that can withstand heating in a microwave oven. Examples of resins include polypropylene, polyethylene, polyester, polystyrene, etc.

As shown in Figures 1(A), 1(B), 2(A), and 2(B), the lid 20 has a top surface portion 21 and a lid edge portion 22. The lid 20 corresponds to the shape of the container body 10 and can be fitted to the container body 10.

The lid 20 is made of paper, resin, or the like. The material of the lid 20 has heat resistance that can withstand heating in a microwave oven. Examples of resins include polypropylene, polyethylene, polyester, and polystyrene. The lid 20 is also thick enough to be deformed by the internal pressure and heat of the container 100 during heating or cooking. The lid 20 is formed, for example, by vacuum forming, compressed air forming, or the like.

The top surface 21 covers the opening 11 of the container body 10. The top surface 21 has a substantially circular shape in a plan view.

Figures 3(A) to 3(D) are conceptual enlarged partial cross-sectional views explaining the lid 20 shown in Figure 1(A) and the like. Figure 3(A) is an A-A cross-sectional view of Figure 1(A), Figure 3(B) is a B-B cross-sectional view, Figure 3(C) is a C-C cross-sectional view, and Figure 3(D) is a D-D cross-sectional view. Figure 4(A) is a diagram showing the cross-sectional views of the lid 20 shown in Figures 3(A) to 3(C) superimposed, and Figure 4(B) is a conceptual cross-sectional view of the container 100 during heating. Also, Figure 4(C) is a partially enlarged view including the steam exhaust portion 24 of the lid 20 on the side of the container 100. Also, Figure 4(D) is an enlarged cross-sectional view of the steam exhaust portion 24. As shown in Figure 3(A) and the like, the top surface portion 21 has a flat portion 21a, a support portion 21b, and a deformation portion 21c, in this order from the center or center passing through the symmetrical axis OA of the container body 10 toward the radially outward direction.

The flat portion 21a is substantially circular in plan view and is disposed around the symmetrical axis OA. The support portion 21b protrudes upward in the direction of the symmetrical axis OA more than the flat portion 21a and the deformation portion 21c. Correspondingly, the support portion 21b has a cylindrical surface, an annular flat surface, and a tapered surface. The support portion 21b supports the shrink film 30 to prevent the film from suppressing deformation of the steam exhaust portion 24 described later, and can reliably develop the exhaust port 24e. In addition, the support portion 21b can support the other lid 20 when stacking the other lid 20. As shown in FIG. 3(D), the support portion 21b has a recess C to prevent the lids 20 from overlapping each other and becoming difficult to peel off when stacking the other lids 20.

The deformation portion 21c extends radially outward from the outer edge of the support portion 21b. The deformation portion 21c promotes local deformation of the lid 20 by the internal pressure of the container 100 when heated. The deformation portion 21c is a curved portion BE having a curved surface. The curved portion BE makes it easier to deform the top surface portion 21. In a cross-sectional view including the symmetrical axis OA, the deformation portion 21c is curved and inclined in a direction from below the symmetrical axis OA to above the lid edge portion 22 located radially outward from the outer edge of the support portion 21b. In the illustrated example, the deformation portion 21c is recessed downward at the step 21d provided on the inside, and is curved and inclined upward from the step 21d toward the outside. When viewed as a whole together with the support portion 21b, the top surface portion 21 is inclined downward from the center radially outward along the symmetrical axis OA, and then inclined upward. By having the above-mentioned inclination of the top surface portion 21, when the top surface portion 21 deforms in accordance with the rise in the internal pressure inside the container 100 during heating, a partial rise occurs, widening the space, making it easier to accumulate steam and further suppressing the rise in internal pressure inside the container 100. In particular, by providing the support portion 21b, the change in inclination of the entire top surface portion 21 from bottom to top can be increased, and the deformation area of the top surface portion 21 during heating can be expanded not only to the deformation portion 21c but also to the outside of the support portion 21b.

The top surface 21 has stoppers ST1 and ST2 that allow the containers 100 to be stacked. The outer stopper ST1 is formed by a step 21d provided in the deformation portion 21c. The inner stopper ST2 is formed by the boundary between the support portion 21b and the deformation portion 21c. Figure 5 is a diagram illustrating an example of stacking containers 100 on the lid 20. As shown in Figure 5, when the containers 100 are containers 101 and 102 of the first and second container standards, the stopper ST1 suppresses the lateral, i.e., horizontal, movement of the container 100 placed on the top of the lid 20. When the container 100 is a container 103 of the third container standard, the stopper ST2 suppresses the lateral, i.e., horizontal, movement of the container 100 placed on the top of the lid 20.

Returning to FIG. 2(A) and the like, the lid edge 22 is detachably fixed to the body edge 14 of the container body 10. The lid edge 22 is cylindrical and extends from the periphery 21e of the top surface 21 so as to expand downward while covering the body edge 14. The lid edge 22 has a fitting portion 23 (see FIGS. 3(B) to 3(D)) that fits into the body edge 14 of the container body 10, and one or more steam exhaust portions 24 (see FIG. 3(A)) that are sandwiched between the fitting portions 23. In the example of FIG. 1(A), the steam exhaust portions 24 are provided at two locations on a straight line perpendicular to the axis of symmetry OA. The steam exhaust portions 24 are provided in the outer peripheral region of the lid edge 22, over a range of 5% to 30%, preferably 10% to 20%, of the entire circumference. In addition, the lid edge 22 has a flat brim-shaped outer edge 25 that extends approximately horizontally from the fitting portion 23 or the steam exhaust portion 24 around the entire circumference of the outermost edge. Although not shown, the outer edge 25 may have multiple projections and recesses to reduce the sharpness of the edge.

As shown in Figures 3(B), 3(C), 4(A), and 4(C), the fitting portion 23 has an annular portion 23a at the top, a first groove portion 23b and a second groove portion 23c at the middle, and a bottom portion 23d.

The annular portion 23a has a shape that roughly follows the shape of the inner surface of the container body 10, specifically, the upper end inner wall of the body side portion 13 of the container body 10 and the upper part of the body edge portion 14, and covers these over almost the entire circumference of the lid edge portion 22 (specifically, the area excluding the part corresponding to the steam exhaust portion 24). The annular portion 23a is formed slightly smaller than the width (length in the lateral or horizontal direction) of the body edge portion 14, and is fitted by deforming the body edge portion 14. The hem portion 23d extends in a curved manner while expanding outward from the first and second groove portions 23b, 23c to the outer edge portion 25.

The first and second grooves 23b, 23c are generally annular grooves extending downward from the annular portion 23a and partially narrowing in the middle of the lid edge portion 22, and are alternately formed around the entire circumference of the fitting portion 23. The first groove 23b and the second groove 23c fit into the body edge portion 14 at the lower part of the body edge portion 14. The cross-sectional shape including the symmetrical axis OA of the first and second grooves 23b, 23c may be an angular U-shape or an arc shape. The first groove 23b is formed shallower than the second groove 23c and fits relatively loosely into the container body 10. This makes it easy to remove the lid 20 from the container body 10 to a suitable degree. The second groove 23c is formed deeper than the first groove 23b and fits relatively tightly into the container body 10. This makes it difficult for the lid 20 to come off the container body 10 during cooking. The arrangement, size, and shape of the first and second grooves 23b, 23c are designed with consideration given to the fitting state of the lid 20 before and after heating, making it easy to fit and difficult for the lid 20 to come off when heated. Even if steam is expelled due to the steam during heating and the deformation of the deformation portion 21c, the container body 10 and the lid 20 are fitted together by the fitting portion 23, so the lid 20 will not come off from the container body 10. By appropriately setting the inclination angle and length of the upper side of the first and second grooves 23b, 23c, the fitting portion 23 will not come off even if the deformation of the deformation portion 21c or the appearance of the exhaust port 24e occurs.

As shown in Figures 3(A), 4(A), 4(C), and 4(D), the steam exhaust section 24 protrudes above the deformation section 21c and is displaced upward as the deformation section 21c deforms. The steam exhaust section 24 faces the inner surface of the container body 10 and has an inner wall 24a including an opposing surface FA that extends in contact with the inner surface of the container body 10, an outer wall 24b that is disposed on the opposite side of the inner wall 24a across the body edge 14, and a top 24c that connects the upper parts of the inner wall 24a and the outer wall 24b.

The inner wall 24a extends in contact with or adjacent to the inner surface of the container body 10, and the outer wall 24b has a gap between it and the body edge 14. This makes it easier to form a gap between the steam exhaust section 24 and the container body 10 during heating. The top 24c is inclined upward from the inner wall 24a to the outer wall 24b in a cross-sectional view. During heating, while maintaining the engagement by the engagement section 23, the steam exhaust section 24 is deformed and displaced in accordance with the deformation of the deformation section 21c, making it easier to form a gap for exhaust at the position of the steam exhaust section 24 among the outer edge of the container 100. This makes it possible to maintain the exhaust function without the lid 20 coming off the container 100 even in the case of high-power and long-term cooking. In addition, the upward inclination of the steam exhaust section 24 makes it possible to prevent the shrink film 30 from suppressing deformation of the steam exhaust section 24 in the container 100 packaged with the shrink film 30.

The steam exhaust section 24 faces the inner surface of the container body 10 and has a partition section 24d including an opposing surface FA that extends in contact with the inner surface of the container body 10. It is desirable that the opposing surface FA is inclined with respect to the symmetrical axis OA of the container body 10. Specifically, the opposing surface FA extends so as to expand upward from the symmetrical axis OA. This can further promote the displacement of the steam exhaust section 24, and ensure the formation of the exhaust port 24e or gap. The partition section 24d is a part or all of the inner wall 24a, and locally separates the inside and outside of the container 100 by utilizing the upper and lower steps on the inside of the steam exhaust section 24. The partition section 24d abuts against the inner surface of the container body 10, specifically, against the upper end inner wall of the main body side portion 13 of the container body 10 or the inner wall of the main body edge portion 14. The partition section 24d has a shape that abuts against the inner wall of the container body 10, thereby preventing the intrusion of foreign matter such as insects and dust. The partition 24d only needs to be in contact with the container body 10 to the extent that it prevents the intrusion of foreign matter. In the lid edge 22, the portion without the steam exhaust section 24 is prevented from intrusion of foreign matter such as insects and dust by the fitting section 23. The height H of the partition 24d is, for example, 1 mm. As shown in FIG. 4B, the partition 24d of the steam exhaust section 24 has an exhaust port forming section VE that is formed by deformation in accordance with the deformation of the deformation section 21c. As a result, the exhaust port forming section VE forms an exhaust port 24e between the steam exhaust section 24 and the body edge 14 by the steam exhaust section 24 being deformed or displaced due to the internal pressure and temperature rise of the container 100 when heated. The exhaust port 24e is also manifested when the lid 20 is fixed with a shrink film 30, a ribbon label, or the like.

The following describes how the state of the lid 20 changes during cooking with heat, with reference to Figures 6(A) and 6(B).

As shown in FIG. 6(A), in the container 100 before cooking, the partition 24d of the steam exhaust section 24 of the lid 20 abuts against the upper inner wall of the main body side section 13 of the container body 10. In other words, the inner wall 24a of the steam exhaust section 24 abuts against the upper inner wall of the main body side section 13 of the container body 10. In the lid edge section 22, the portion where the steam exhaust section 24 is provided prevents foreign matter from entering the inside of the container 100 by the partition 24d. In addition, in the lid edge section 22, the portion where the steam exhaust section 24 is not provided prevents foreign matter from entering by the fitting section 23.

As shown in FIG. 6B, when the internal pressure of the container 100 increases during cooking using a microwave oven or the like, the deformed portion 21c of the top surface 21 deforms so as to bulge upward due to the increased pressure and softening of the lid 20. As a result of this deformation, the partition portion 24d of the steam exhaust portion 24 moves or deforms upward in the container 100, forming an exhaust port 24e by the exhaust port forming portion VE of the steam exhaust portion 24. Steam is then exhausted from the exhaust port 24e. Due to the above-mentioned steam exhaust method of the container 100, as the deformation portion 21c deforms during heating, the partition portion 24d of the steam exhaust portion 24 separates from the inner surface of the container body 10 so that steam can be exhausted, thereby exhausting steam from inside the container 100. Although not shown in the figure, after cooking, the lid 20 returns to its original state or a shape close to its original state due to the reduction in the internal pressure of the container 100.

(Example)
Examples of this embodiment are described below. Figures 7(A) and 7(B) are diagrams for explaining the shape and dimensions of the fitting portion 23 of the lid edge portion 22. In Figures 7(A) and 7(B), the symbol X1 is the fitting diameter, which is the diameter of the fitting portion 23 of the lid 20, the symbol X2 is the radial length (groove depth) of the first groove portion 23b, and the symbol X3 is the radial length (groove depth) of the second groove portion 23c. The symbol θ1 is the upper inclination angle when the first and second groove portions 23b and 23c are U-shaped, and the symbol θ2 is the lower inclination angle.

The dimensions, shape, and post-heating condition evaluation of the samples used in the examples are shown below. "Fit/unfit" indicates the fit of the lid 20 before heating. "Microwave evaluation" indicates the fit of the lid after heating in a microwave oven. In the "microwave evaluation," 100 g or 300 g of water was placed in the sample container 100, and the fit of the lid 20 was evaluated after heating at 1520 W for 90 minutes.

(Sample 1)
Fitting diameter X1: 141.2 mm
Shape of the first and second grooves: U-shape (see FIG. 7A)
Length of first groove portion X2: 0.4 mm
Length of second groove portion X3: 0.4 mm
Upper inclination angle θ1: 30°
Lower inclination angle θ2: 45°
Fitting and opening: relatively good Range evaluation: no lid coming off (sample 2)
Fitting diameter X1: 140.9 mm
Shape of the first and second grooves: U-shape (see FIG. 7A)
Length of first groove portion X2: 0.4 mm
Length of second groove portion X3: 0.5 mm
Upper inclination angle θ1: 30°
Lower inclination angle θ2: 45°
Fitting/unfitting: Relatively difficult to fit Microwave evaluation: No lid came off (sample 3)
Fitting diameter X1: 141.2 mm
Shape of the first and second grooves: U-shape (see FIG. 7A)
Length of first groove portion X2: 0.4 mm
Length of second groove portion X3: 0.4 mm
Upper inclination angle θ1: 45°
Lower inclination angle θ2: 45°
Fitting and opening: relatively good Range evaluation: lid came off (sample 4)
Fitting diameter X1: 141.2 mm
Shape of the first and second grooves: arc shape (see FIG. 7B)
Length of first groove portion X2: 0.5 mm
Length of second groove portion X3: 0.4 mm
Fitting and unpacking: Good Range evaluation: Lid came off

As can be seen from samples 1 to 3, the smaller the inclination angle of the upper side of the first and second groove portions 23b, 23c and the longer the groove length, the less likely the lid 20 will come off after heating. Also, as can be seen from samples 1 and 4, regarding the shape of the first and second groove portions 23b, 23c, it is found that a U-shape makes it less likely that the lid 20 will come off after heating than an arc-shaped shape.

According to the lid 20 of the container 100 described above, the top surface 21 has a deformation portion 21c that can deform when heated, which makes it possible to gently increase the internal pressure inside the container 100 when heated. In addition, the lid edge 22 has a steam exhaust portion 24, and the inner wall 24a of the steam exhaust portion 24 has a partition portion 24d, which makes it possible to prevent the intrusion of foreign matter such as insects and dust. The steam exhaust portion 24 opens as the deformation portion 21c deforms, and exhausts steam.

The present invention has been described above based on an embodiment, but the present invention is not limited to the above embodiment and various modifications are possible.

For example, the shape of the container body 10 and the shape of the lid 20 can be modified as appropriate within the scope of this embodiment. As shown in FIG. 8(A), a step 21d may be provided only in the extended region of the deformation portion 21c of the top surface 21 that corresponds to the steam exhaust portion 24. As shown in FIG. 8(B), a support portion 21b may not be provided on the top surface 21. As shown in FIG. 8(C), a step 21d may not be provided on the support portion 21b and the deformation portion 21c of the top surface 21.

In the above embodiment, the deformed portion 21c is a curved portion BE, but it may be a bent portion that is angular rather than curved in cross section.

In the above embodiment, the container 100 is not limited to a rectangular shape in plan view, but can be any of a variety of polygonal shapes. The container 100 may also be elliptical.

In the above embodiment, an example was given in which two steam exhaust sections 24 were provided, but one or three or more may be provided as long as the fitting function of the lid 20 is maintained.

In the above embodiment, the inner wall of the fitting portion 23, including the opposing surface facing the inner surface of the container body 10, is not limited to being aligned along the inner surface of the container body 10, and there may be a gap between the inner wall of the fitting portion 23 and the inner wall of the container body 10.

In the above embodiment, the opposing surface FA depends on the shape of the inner surface of the container body 10 and may be parallel to the axis of symmetry OA of the container body 10 without being inclined.

In the above embodiment, the top 24c of the steam exhaust section 24 is shaped to slope upward from the inner wall 24a toward the outer wall 24b, but it may be shaped to follow the shape of the body edge 14 of the container body 10 to the extent that it does not fit, or may be shaped without slope.

10...container body, 11...opening, 12...bottom surface, 12a...periphery, 13...side surface of body, 13a...upper end, 14...body edge, 15...legs, 20...lid, 21...top surface, 21a...flat portion, 21b...support portion, 21c...deformed portion, 21d...step, 21e...periphery, 22...lid edge, 23...fitting portion, 23a...annular portion, 23b...first groove portion, 23c...second groove portion, 23d...bottom portion, 24...steam exhaust portion, 24a...inner wall, 24b...outer wall, 24c...top portion, 24d...partition portion, 24e...exhaust port, 25...outer edge, 30...shrink film, 100...container, BE...curved portion, C...recess, FA...opposite surface, OA...symmetric axis, ST1, ST2...stopper, VE...exhaust port forming part

Claims (9)

A container body for accommodating food ;
A container comprising a lid having a top surface portion covering an opening of the container body and a lid edge portion removably fixed to a body edge portion of the container body,
The top surface portion has a deformation portion that promotes local deformation due to internal pressure when heated,
The lid edge portion has a fitting portion that fits into the body edge portion and one or more steam exhaust portions disposed between the fitting portions,
The steam discharge portion protrudes upward from the deformation portion,
the steam discharge portion has a partition portion that is displaced upward as the deformation portion deforms, faces an inner surface of the container body, and includes an opposing surface that extends in contact with the inner surface of the container body before the deformation portion deforms ,
a peripheral edge of the deformation portion of the top surface portion reaches a position higher than the fitting portion in the steam exhaust portion and is connected to the partition portion;
A container, wherein the deformed portion is curved and inclined toward the periphery so that the inclination increases in a direction from below to above the axis of symmetry of the container body when viewed in a cross-section including the axis of symmetry of the container body . The steam exhaust portion has an inner wall including the opposing surface, an outer wall disposed on the opposite side of the inner wall across the main body edge portion, and a top portion connecting the inner wall and an upper portion of the outer wall,
The container of claim 1 , wherein the top slopes upwardly from the inner wall toward the outer wall. The container of claim 2 , wherein the inner wall extends against or adjacent an inner surface of the container body, and the outer wall has a gap between it and an edge of the body. The container according to any one of claims 1 to 3, wherein the partition portion has an exhaust port forming portion that is deformed in accordance with the deformation of the deformation portion. The container according to any one of claims 1 to 4, wherein the opposing surfaces are inclined with respect to an axis of symmetry of the container body. The container according to any one of claims 1 to 5, wherein the top surface portion, in the cross -sectional view, inclines downwardly from the center radially outwardly with respect to an axis of symmetry of the container body, and then inclines upwardly. The top surface portion has a support portion closer to the center than the deformation portion.
7. The container of claim 6. The container according to any one of claims 1 to 7, wherein the deformed portion is either a curved portion or a bent portion. A method for venting steam from a container including a container body for accommodating food, a lid having a top surface portion covering an opening of the container body, and a lid edge portion removably fixed to a body edge portion of the container body, comprising:
The top surface portion has a deformation portion that promotes local deformation due to internal pressure when heated,
The lid edge portion has a fitting portion that fits into the body edge portion and one or more steam exhaust portions disposed between the fitting portions,
The steam discharge portion protrudes upward from the deformation portion,
the steam discharge portion has a partition portion that is displaced upward as the deformation portion deforms, faces an inner surface of the container body, and includes an opposing surface that extends in contact with the inner surface of the container body before the deformation portion deforms ,
With the deformation of the deformation portion upon heating, the partition portion separates from the inner surface of the container body to allow steam to be discharged , thereby discharging steam from inside the container;
a peripheral edge of the deformation portion of the top surface portion reaches a position higher than the fitting portion in the steam exhaust portion and is connected to the partition portion;
A method for discharging steam from a container, wherein the deformed portion is curved and inclined toward the periphery so that the inclination increases in a direction from below to above the axis of symmetry of the container body when viewed in a cross-section including the axis of symmetry of the container body.

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