Container for food packaging, vacuum forming mold, and method for manufacturing container

Abstract

To provide a container for food packing that can be improved in sealability in a state where a container main body is closed with a lid body.SOLUTION: A container 1 for storing a food F comprises a container main body 2 having an opening M for putting in and taking out a food, a lid body 3 for closing the opening M, and a hinge part 4 that connects the container main body 2 to the lid body 3 openably and closably and can deform elastically. The container main body 2 comprises an opening wall 5 formed along an outer periphery of the opening M, and the lid body 3 comprises a protrusion part 7 internally fitted to the opening wall 5. The opening wall 5 comprises a concave-side inner wall part 52 inclined to resist restoring force of the hinge part 4. The protrusion part 7 comprises a convex-side outer wall part 74 provided to overlap with the concave-side inner wall part 52. At least either of the concave-side inner wall part 52 and the convex-side outer wall part 74 is provided with corner parts 11a-11d, and the other of the concave-side inner wall part and the convex-side outer wall part is provided with corner receiving parts 12a-12d.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a food packaging container for packaging foods such as skewer dumplings and yakitori, a vacuum forming mold for manufacturing the food packaging container, and a container manufacturing method.

Background Art

[0002] Plastic food packaging containers for packaging foods such as skewer dumplings and yakitori are known. The food packaging container includes, for example, a container body having an opening for taking in and out food, a lid body attached to the container body to close the opening, and a hinge portion that connectably opens and closes the container body and the lid body. In this type of packaging container, it is necessary to pay attention so that sauces such as honey and tare attached to the food do not leak when the lid body is closed. For example, the packaging container described in Patent Document 1 includes a lid body provided with a ridge portion that fits inside the opening wall of the container body. By fitting the lid body inside the container body, leakage of sauces is suppressed and the sealing property is enhanced.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In this type of food packaging container, a gap may occur between the opening wall in the fitted state and the ridge portion, and the sealing property may deteriorate.

[0005] An object of the present invention is to solve the above problems, and an object is to provide a food packaging container with improved sealing property when the container body is closed with the lid body.

Means for Solving the Problems

[0006] The present invention relates to a food packaging container for containing food, comprising a container body having an opening for taking food in and out, a lid for closing the opening, and a hinge portion that elastically deforms and connects the container body and the lid in an openable and closable manner. The container body includes an opening wall provided along the outer periphery of the opening, the lid includes a protruding portion that fits inside the opening wall, the opening wall includes a concave inner wall portion that is inclined so as to oppose the restoring force of the hinge portion, the protruding portion includes a convex outer wall portion provided so as to overlap the concave inner wall portion, at least one of the concave inner wall portion and the convex outer wall portion is provided with a corner portion that bends convexly and is continuous along the entire circumference of the opening, and the other of the concave inner wall portion and the convex outer wall portion is provided with a corner receiving portion that contacts the corner portion.

[0007] The lid is connected to the container body via the hinge portion. The lid is attached so as to close the opening of the container body while bending the hinge portion. The container body includes an opening wall, and the opening wall includes a concave inner wall portion. The lid includes a protruding portion that fits inside the opening wall, and the protruding portion includes a convex outer wall portion that overlaps the concave inner wall portion. At least one of the concave inner wall portion and the convex outer wall portion is provided with a corner portion, and the other is provided with a corner receiving portion that contacts the corner portion. The corner portion forms a contact area that continuously closes over the entire circumference of the opening by contacting the corner receiving portion, and this contact area serves as a weir to prevent liquid leakage and the like. Further, the hinge portion connecting the lid and the container body is elastically deformable, and the restoring force of the hinge portion acts in the opening direction on the lid in the closed state. The concave inner wall portion of the opening wall is inclined so as to oppose the restoring force of the hinge portion, and the convex outer wall portion of the protruding portion is strongly pressed against the concave inner wall portion by the repulsion of the concave inner wall portion that opposes the restoring force. As a result, the corner portion and the contact area in contact with the corner portion are also firmly and stably maintained, and the sealing performance in the state where the container body is closed with the lid is improved.

[0008] In the above-mentioned food packaging container, the opening wall includes an upper end portion surrounding the opening and a concave inner wall portion disposed on the inner peripheral side of the upper end portion. The concave inner wall portion includes an inner wall upper edge portion and an inner wall lower edge portion that is farther from the upper end portion than the inner wall upper edge portion. The concave inner wall portion may be inclined such that the inner diameter of the inner region expands more in the inner wall lower edge portion than in the inner wall upper edge portion. Due to this inclination, the concave inner wall portion comes into contact with the convex outer wall portion against the restoring force of the hinge portion.

[0009] In the above-mentioned food packaging container, the corner receiving portion may be at least one of a valley shape bent in a concave shape so as to be able to receive a corner portion and a flat shape with a linear cross section. The corner portion can form a contact area by contacting the corner receiving portion having a valley shape or a flat shape.

[0010] In the above-mentioned food packaging container, a plurality of corner portions are provided. The corner portions are provided on both the concave inner wall portion and the convex outer wall portion, and the corner receiving portions may be provided on both the concave inner wall portion and the convex outer wall portion. By providing corner portions on both the concave inner wall portion and the convex outer wall portion, the sealing property can be enhanced.

[0011] In the above-mentioned food packaging container, the opening wall includes an upper end portion surrounding the opening and a concave inner wall portion disposed on the inner peripheral side of the upper end portion. In a state where the protruding strip portion is fitted inside the opening wall, the corner portion of the concave inner wall portion may be provided at a position closer to the upper end portion than the corner portion of the convex outer wall portion. When fitting the protruding strip portion inside the opening wall, the opening wall is less likely to deform, and the corner portion of the concave inner wall portion of the opening wall has higher shape stability than the corner portion of the convex outer wall portion of the protruding strip portion. As a result, even if the liquid exceeds the corner portion of the convex outer wall portion, the liquid can be accurately blocked by the corner portion of the concave inner wall portion.

[0012] In the above-mentioned food packaging container, the opening wall includes an upper end portion surrounding the opening, a concave inner wall portion disposed on the inner peripheral side of the upper end portion, and a concave inclined portion provided between the upper end portion and the concave inner wall portion and inclined with respect to the concave inner wall portion. The protruding strip portion may include a convex inclined portion inclined with respect to the convex outer wall portion so as to overlap the concave inclined portion. The sealing property is further enhanced by the contact between the concave inclined portion and the convex inclined portion.

[0013] The present invention also relates to a vacuum forming mold for manufacturing a food packaging container in which a container body and a lid are connected by a hinge portion so as to be openable and closable, the mold including a cavity capable of forming a food packaging container in close contact with a sheet material, the cavity including a body forming portion capable of forming the container body, a lid forming portion capable of forming the lid, and a hinge forming portion capable of forming the hinge portion. The body forming portion includes an opening wall forming portion capable of forming an opening wall provided along the outer periphery of the opening of the container body. The lid forming portion includes a ridge forming portion capable of forming a ridge portion that fits inside the opening wall. The opening wall forming portion includes an upper end forming portion capable of forming an upper end portion surrounding the opening, and a concave inner wall forming portion disposed on the inner peripheral side of the upper end portion and capable of forming a concave inner wall portion into which the opening wall fits. The ridge forming portion includes a convex outer wall forming portion capable of forming a convex outer wall portion provided so as to overlap the concave inner wall portion. The concave inner wall forming portion has an inner wall upper edge portion and an inner wall lower edge portion that is farther from the upper end portion than the inner wall upper edge portion, and the concave inner wall forming portion is capable of forming a concave inner wall portion in which the inner diameter of the inner region is inclined so as to expand toward the inner wall lower edge portion relative to the inner wall upper edge portion. At least one of the concave inner wall forming portion and the convex outer wall forming portion can be formed such that convexly bent corners are continuous over the entire circumference of the opening, and the other of the concave inner wall forming portion and the convex outer wall forming portion can form a corner receiving portion that contacts the corners.

[0014] The present invention also relates to a container manufacturing method for manufacturing a food packaging container by vacuum forming using the above-described vacuum forming mold. In this method, the vacuum forming mold is brought into contact with a sheet material such that the cavity faces the sheet material, the sheet material is heated, and the interior of the cavity is suctioned to cause the sheet material to adhere to the cavity and form a food packaging container. Then, the heating of the food packaging container is released, and the food packaging container is detached from the vacuum forming mold.

[0015] By vacuum forming using the vacuum forming mold, it is possible to manufacture a food packaging container having improved sealing performance in a state where the container body is closed by the lid.

Advantages of the Invention

[0016] According to the present invention, the sealing performance in the state where the container body is closed by the lid is improved.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0018] Hereinafter, a container for food packaging according to an embodiment of the present invention will be described with reference to the drawings. Note that the container for food packaging of the present invention is not limited to this embodiment only.

[0019] The food packaging container of the embodiment (hereinafter referred to as "container 1") is a container for accommodating food F such as dumplings and yakitori (see FIG. 3). For the food F, for example, sauces such as honey and tare are applied, and when the food F is accommodated in the container 1, it is important to have a sealing property so that the sauces do not leak out.

[0020] As shown in FIGS. 1, 2, 3, and 4, the container 1 includes a container body 2 having an opening M for taking in and out the food F, a lid body 3 for closing the opening M, and a hinge portion 4 for connecting the container body 2 and the lid body 3 in an openable and closable manner. The lid body 3 is mounted so as to be fitted inside the opening M of the container body 2 to ensure a sealing property. When touching an obstacle such as a shopper or another product, the lid body 3 is less likely to come off from the container body 2 in the case of internal fitting than external fitting, which is advantageous in maintaining the sealing property. Further, the hinge portion 4 is elastically deformable, and in a state where the lid body 3 closes the opening M of the container body 2, a restoring force by the hinge portion 4 acts on the lid body 3. In the container 1, by utilizing the restoring force of the hinge portion 4, the sealing property can be further improved as compared with a mere internal fitting of the lid body 3.

[0021] Container 1 is manufactured using, for example, a synthetic resin sheet, and is integrally molded into a shape in which a container body 2 and a lid 3 are joined via a hinge portion 4. The container 1 according to the present embodiment is transparent, but is not limited to being transparent.

[0022] The structure of container 1 will be described. The structure of container 1 will be basically described based on the state in which the lid 3 is removed and the opening M of the container body 2 is open, that is, the unfolded state. In the following description, when the state in which the lid 3 is attached to the container body 2 and the opening M is closed is taken as a reference, it is supplemented and explained that the lid 3 is in a state of closing the opening M. Further, when describing while indicating the vertical direction such as the upper part, the lower part, the upper side, or the lower side, it is based on the container body 2 installed so as to stably hold the food F, and an installation state in which the opening M is on the upper side is assumed. Further, the "lateral direction" means a direction that is approximately orthogonal to the vertical direction for convenience. For example, when the vertical direction is the up-and-down direction, the horizontal direction is the lateral direction. Further, the "inward" means the direction toward the inside of the container body 2 or the direction toward the inside of the container 1 when the lid 3 is closed. Further, the "outward" means the direction toward the outside, which is the opposite side to the "inward".

[0023] The schematic shape of the container body 2 is a substantially rectangular shape that is horizontally long in plan view (see Fig. 3). The upper part of the container body 2 is open and an opening M is formed. The container body 2 includes a bottom portion 21 provided at the lower part on the side opposite to the opening M, and a side wall 22 erected from the periphery of the bottom portion 21. A plurality of linear protrusions 21a protruding inward (upward) are arranged side by side on the bottom portion 21. The protrusions 21a abut against the food F accommodated inside and support the food F in a state of being slightly lifted from the bottom portion 21. A plurality of depressions 23 are formed along the periphery of the bottom portion 21. The back side (outer side) of the depression 23 protrudes to form legs 24 (see Fig. 5). The space between the legs 24 is a recessed portion when viewed from the outside, and a label for food display or the like is pasted on the recessed portion. A plurality of grooves serving as ribs are provided in the depression 23.

[0024] As shown in FIGS. 1, 5, and 6, the side wall 22 includes a lower wall 25 erected from the depression 23 of the bottom 21, a middle wall 26 erected by bending from the lower wall 25, and an upper wall erected by bending from the middle wall 26. The upper wall is an opening wall 5 that can receive the ridge portion 7 of the lid body 3 in a fitting manner, and is provided along the outer periphery of the opening M. The lower wall 25 is provided with a plurality of grooves 25a formed so as to be continuous with the grooves for ribs provided in the depression 23, forming a streamline-shaped rib groove as a whole. The middle wall 26 bends from the lower wall 25 and projects laterally, and further bends so as to rise upward.

[0025] As shown in FIG. 6, the opening wall 5 includes an extended portion 51 that projects outward from the upper end of the middle wall 26. The extended portion 51 includes a horizontal extended portion 51a that bends from the middle wall 26 and extends laterally, and an inclined extended portion 51b that bends from the horizontal extended portion 51a and extends obliquely upward.

[0026] The opening wall 5 includes a concave inner wall portion 52 erected from the extended portion 51. The ridge portion 7 of the lid body 3 is fitted into the concave inner wall portion 52. A force in the direction of separating from the fitting acts on the ridge portion 7 due to the restoring force of the hinge portion 4, and the concave inner wall portion 52 is inclined so as to be able to hold the fitting state of the ridge portion 7 against the restoring force of the hinge portion 4. The concave inner wall portion 52 has an inner wall lower edge portion 52a (the lower edge in FIG. 6), which is one peripheral edge on the extended portion 51 side, and an inner wall upper edge portion 52b (the upper edge in FIG. 6), which is the other peripheral edge on the opposite side.

[0027] The opening wall 5 includes a concave inclined portion 53 that is bent from the inner wall upper edge portion 52b of the concave inner wall portion 52 and extends obliquely upward and outward, and an upper end portion 54 that is bent from the upper end of the concave inclined portion 53 and extends horizontally. The upper end portion 54 is provided in a continuous endless closed loop shape (for example, a substantially rectangular loop shape) in a plan view (see FIG. 3). The inner region surrounded by the upper end portion 54 substantially forms the opening M. Additionally, the upper end portion 54 is provided so as to surround the opening M, and the inner periphery of the upper end portion 54 is the peripheral edge on the side facing the opening M. Further, the concave inclined portion 53 is provided along the inner periphery of the upper end portion 54 and serves as the introduction portion of the ridge portion 7 of the lid body 3 to be fitted therein.

[0028] As shown in FIGS. 1, 3, 5, 6, and 8, the opening wall 5 includes a flange receiving portion 6 that extends along the outer periphery of the upper end portion 54, and a connection wall portion 55 connected to the hinge portion 4. The outer periphery of the upper end portion 54 means the peripheral edge on the side opposite to the inner periphery on the opening M side. The flange receiving portion 6 is provided so as to project outward from the upper end portion 54 and is the portion that contacts the flange portion 8 of the lid body 3 when the lid body 3 is closed. The flange receiving portion 6 includes a support seat portion 61 provided so as to align with the upper end portion 54, and a connecting portion 62 that is displaced downward from the upper end portion 54 and connects the lower portion of the connection wall portion 55 and the support seat portion 61. The meaning that the support seat portion 61 aligns with the upper end portion 54 means that the positions in the vertical direction (height direction) are aligned. For example, the support seat portion 61 of the present embodiment is provided so as to be flush and continuous with the upper end portion 54. The flange portion 8 is mainly supported by contacting the support seat portion 61.

[0029] The connecting wall portion 55 stands upright from the hinge portion 4 and bends at the upper part to be connected to the upper end portion 54. The connecting wall portion 55 is provided not on the entire circumference of the upper end portion 54 but on a part connected to the hinge portion 4 (see Fig. 1). For example, the upper end portion 54 (see Fig. 3) is a portion provided so as to surround a substantially horizontally long rectangular opening M with some curvature in plan view. That is, it can be assumed that the upper end portion 54 according to the present embodiment includes a pair of opposing long side portions and a pair of opposing short side portions. Here, among the pair of long side portions, one long side portion is a portion on the side connected to the hinge portion 4 (hereinafter referred to as the "connection side region"), and the other long side portion is a portion on the opposite side arranged so as to sandwich the opening M (hereinafter referred to as the "opposite side region"). The connecting wall portion 55 is mainly provided along the connection side region and is not provided in the opposite side region.

[0030] The connecting wall portion 55 (see Fig. 6) has a shape stability such that it can maintain an upright state without following the flexibility of the hinge portion 4. For example, the connection portion between the connecting wall portion 55 and the hinge portion 4 is bent, and the deflection of the hinge portion 4 is absorbed by this bending and is not transmitted to the connecting wall portion 55. That is, it can also be explained that the connecting wall portion 55 has a structural strength to prevent continuous deflection following this deflection even when the hinge portion 4 is deflected.

[0031] The connection side region and the opposite side region of the upper end portion 54 are connected to a pair of opposing short side portions (see Figs. 1 and 3). The connecting wall portion 55 is provided not only in the connection side region but also to partially extend to the short side portions. The connecting wall portion 55 of the short side portion gradually decreases in height from the connection side region side to the opposite side region side and finally disappears flush with the upper end portion 54.

[0032] The flange receiving portion 6 extends along the outer periphery of the upper end portion 54 and is provided in a region other than the connection wall portion 55 in the entire circumference of the upper end portion 54 in plan view. Further, among the flange receiving portion 6, the region aligned with the upper end portion 54 is the support seat portion 61, and the region that is not aligned with the upper end portion 54 and is at a position lower than the upper end portion 54 is the connection portion 62. Also, among the flange receiving portion 6, the region provided along the connection wall portion 55 can be described as the connection portion 62, and the region not along the connection wall portion 55 is the support seat portion 61.

[0033] The hinge portion 4 extends linearly along a part of the opening wall 5 of the container body 2 in plan view. The opening wall 5 includes an upper end portion 54, and the upper end portion 54 includes a connection side region as described above. The hinge portion 4 extends along the connection side region. In a cross-sectional view along the width direction orthogonal to the longitudinal direction (extending direction) of the hinge portion 4 (see FIG. 6), the hinge portion 4 has a substantially U-shaped curved shape that bulges downward. One end (one edge) in the width direction of the hinge portion 4 is connected to the connection wall portion 55 of the opening wall 5. The other end (the other edge) of the hinge portion 4 is connected to the hinge connection portion 9 of the lid body 3. The hinge connection portion 9 is bent and connected to the hinge portion 4, and the fold line substantially generated by the bending forms the boundary between the hinge portion 4 and the hinge connection portion 9. Note that the hinge portion 4 according to the present embodiment has a smoothly curved shape without bending in the middle and is symmetric about the center in the width direction.

[0034] The hinge portion 4 is elastically deformable and has flexibility that allows the lid body 3 to tilt toward the container body 2 side. For example, regarding the hinge portion 4 extending along the opening wall 5, the longitudinal direction is considered the extending direction, and the direction orthogonal to the extending direction is considered the width direction. Here, an axis along the extending direction passing through the center in the width direction of the hinge portion 4 is assumed as the reference axis Sf. The hinge portion 4 includes a main flexible portion 41 (see FIGS. 3 and 4) having flexibility to allow bending around the reference axis Sf. Further, the hinge portion 4 includes a constriction portion 42 connected to both ends of the main flexible portion 41. The constriction portion 42 has a narrower width as it is farther from the main flexible portion 41 in plan view (see FIG. 3). For example, the main flexible portion 41 (see FIG. 6) has a curved shape along the reference axis Sf in cross-sectional view and extends along the reference axis Sf in a state where the distance from the reference axis Sf is constant. In contrast, the constriction portion 42 has a reduced diameter such that the distance from the reference axis Sf becomes narrower as it is farther from the main flexible portion 41. When tilting the lid body 3 toward the container body 2 side via the hinge portion 4, the constriction portion 42 can prevent the lid body 3 from swaying left and right, the orbit of the lid body 3 is stabilized, and misalignment of the inner fitting is less likely to occur.

[0035] As shown in FIGS. 6 and 7, the lid body 3 includes a cover portion 31 that covers the opening M when attached to the container body 2, a protrusion portion 7 that protrudes from the cover portion 31 and is provided along the peripheral edge portion 31c of the cover portion 31, and a hinge connection portion 9 that is connected to the protrusion portion 7 and the hinge portion 4 and has flexibility. Note that the hinge connection portion 9 may be omitted, and the protrusion portion 7 may be directly connected to the hinge portion 4.

[0036] The cover portion 31 has a shape following the shape of the opening M in plan view, and in this embodiment, it is a substantially rectangular shape following the substantially rectangular opening M (see FIG. 4). The cover portion 31 is formed in a three-dimensional surface shape having a depth (bulge) such that it is difficult for sauces or the like applied to the food F to adhere. For example, when taking the state where the lid body 3 is closed as a reference (see FIG. 7), the cover portion 31 includes a flat ceiling portion 31a extending in the lateral direction, a side wall portion 31b provided along the outer peripheral edge of the ceiling portion 31a so as to surround the ceiling portion 31a and inclined downward from the outer peripheral edge of the ceiling portion 31a, and a peripheral edge portion 31c protruding laterally outward from the lower end portion (edge portion) of the side wall portion 31b. The peripheral edge portion 31c corresponds to the outer peripheral edge of the cover portion 31.

[0037] The ridge portion 7 is provided along the peripheral edge portion 31c of the cover portion 31. For example, the ridge portion 7 is continuously provided over the entire circumference of the peripheral edge portion 31c of the cover portion 31, and when the lid body 3 is attached to the container body 2, the entire circumference of the ridge portion 7 is internally fitted to the opening wall 5 (see FIGS. 7 and 8).

[0038] The ridge portion 7 is formed as a whole in a shape that bends upward from the peripheral edge portion 31c and further has a plurality of bent portions. Specifically, the ridge portion 7 includes an inner side surface portion 71 that rises up so as to protrude from the peripheral edge portion 31c, and a fitting end portion 72 that bends from the tip of the inner side surface portion 71 and extends laterally. The inner side surface portion 71 is continuously provided over the entire circumference of the peripheral edge portion 31c. The fitting end portion 72 is arranged so as to overlap with the horizontal expansion portion 51a of the opening wall 5 when the ridge portion 7 is internally fitted to the opening wall 5.

[0039] Further, the ridge portion 7 includes a chamfered portion 73 provided along the outer periphery of the fitting end portion 72, and a convex side outer wall portion 74 provided along the outer periphery of the chamfered portion 73. The chamfered portion 73 is an inclined wall portion that bends from the outer periphery of the fitting end portion 72 and is inclined with respect to the fitting end portion 72. The convex side outer wall portion 74 is a wall portion that bends from the outer periphery of the chamfered portion 73 and extends so as to face the inner side surface portion 71. The chamfered portion 73 is arranged so as to overlap with the inclined expansion portion 51b of the opening wall 5 when the ridge portion 7 is internally fitted to the opening wall 5.

[0040] The convex outer wall portion 74 is continuously provided substantially along the entire circumference of the peripheral edge 31c of the cover portion 31, and is fitted into the opening wall 5 of the container body 2. When the opening M is closed by the lid body 3, the convex outer wall portion 74 overlaps the concave inner wall portion 52 of the opening wall 5 and contacts the concave inner wall portion 52.

[0041] The convex outer wall portion 74 has one peripheral edge on the chamfered portion 73 side (the upper peripheral edge in FIG. 6) and the other peripheral edge on the opposite side (the lower peripheral edge in FIG. 6). The ridge portion 7 includes a convex inclined portion 75 provided along the other peripheral edge of the convex outer wall portion 74. The convex inclined portion 75 is bent from the convex outer wall portion 74 and is inclined so as to spread with respect to the convex outer wall portion 74. The convex inclined portion 75 contacts so as to overlap the concave inclined portion 53 of the opening wall 5 when the ridge portion 7 is fitted into the opening wall 5 (see FIG. 8).

[0042] The ridge portion 7 includes a flange portion 8 that continuously extends along the outer periphery of the convex outer wall portion 74. The meaning of continuous means that there is no missing portion in the middle. The flange portion 8 is provided so as to project laterally from the convex inclined portion 75. The flange portion 8 includes a main placement portion 81 placed on the flange receiving portion 6 of the container body 2 and a communication placement portion 82 connected to the hinge connection portion 9. The main placement portion 81 and the communication placement portion 82 are connected to each other on the same plane to form an endless closed loop (substantially rectangular) and are continuously provided along the entire circumference in the circumferential direction of the ridge portion 7. When the lid body 3 is closed, the main placement portion 81 is placed on the upper end portion 54 of the opening wall 5 and the flange receiving portion 6, and the communication placement portion 82 is placed only on the upper end portion 54.

[0043] The lid body 3 is provided with a hinge connection portion 9 disposed between the ridge portion 7 and the hinge portion 4. The hinge connection portion 9 is connected to the ridge portion 7 and the hinge portion 4. The hinge connection portion 9 includes a lower connection portion 91, a stepped connection portion 92, and an upper connection portion 93. The lower connection portion 91 is connected to the hinge portion 4 and is provided so as to bend from the hinge portion 4 and project laterally. The stepped connection portion 92 is bent and connected so as to be inclined with respect to the lower connection portion 91. The upper connection portion 93 is provided so as to project laterally with respect to the stepped connection portion 92.

[0044] Next, referring to FIGS. 6 and 8, the concave inner wall portion 52 of the opening wall 5 and the convex outer wall portion 74 of the ridge portion 7 fitted inside the concave inner wall portion 52 will be described in detail.

[0045] When the hinge portion 4 is elastically deformed, a restoring force that tries to return to its original state is generated in the hinge portion 4. The restoring force of the hinge portion 4 acts as a repulsive force on the object being elastically deformed, and the object tries to resist the restoring force. In the present embodiment, the concave inner wall portion 52 of the opening wall 5 functions so as to resist the restoring force of the hinge portion 4.

[0046] Specifically, first, the convex outer wall portion 74 of the ridge portion 7 is fitted inside the concave inner wall portion 52 of the opening wall 5. Due to this fitting, a static frictional force is generated between the convex outer wall portion 74 and the concave inner wall portion 52, and this static frictional force becomes a force that resists the restoring force of the hinge portion 4. Further, the concave inner wall portion 52 is inclined so as to resist the restoring force of the hinge portion 4. For example, the hinge portion 4 is elastically deformed so as to be distorted around the reference axis Sf, and the convex outer wall portion 74 moves on a predetermined locus in accordance with the elastic deformation of the hinge portion 4. The concave inner wall portion 52 is inclined so as to interfere with the movement locus of the convex outer wall portion 74.

[0047] The concave inner wall portion 52 includes an inner wall upper edge portion 52b and an inner wall lower edge portion 52a that is on the opposite side of the inner wall upper edge portion 52b and farther from the upper end portion 54 than the inner wall upper edge portion 52b. The concave inner wall portion 52 is inclined such that the inner diameter IR (see FIG. 5) of the inner region expands more at the inner wall lower edge portion 52a than at the inner wall upper edge portion 52b.

[0048] Referring to FIGS. 8 and 9, the inclination of the concave-side inner wall portion 52 will be described more specifically. FIG. 8 is a diagram for explaining the inclination of the concave-side inner wall portion 52, and FIG. 9 is a diagram for explaining the inclination of the concave-side inner wall portion from another side view.

[0049] First, an explanation will be given with reference to FIG. 8. For example, assume a plane La including the upper end portion 54 surrounding the periphery of the opening M. Also, in a cross-sectional view of the concave-side inner wall portion 52, assume a first straight line Lb passing through a representative point of the inner wall upper edge portion 52b of the concave-side inner wall portion 52 and perpendicular to the plane La. Further, in a cross-sectional view of the concave-side inner wall portion 52, assume a second straight line Lc connecting the representative point of the inner wall upper edge portion 52b and the representative point of the inner wall lower edge portion 52a of the concave-side inner wall portion 52. Note that the representative points of the inner wall upper edge portion 52b and the inner wall lower edge portion 52a mean the locations facing the convex-side outer wall portion 74 on the opening M side in the cross-sectional view. Here, the second straight line Lc is inclined such that the inner wall lower edge portion 52a is disposed more outward than the inner wall upper edge portion 52b with respect to the first straight line Lb. The inclination angle θ of the second straight line Lc with respect to the first straight line Lb is, for example, 2° to 10°. Also, the inclination angle θ may be 3° to 9°, or may be 4° to 8°.

[0050] Next, a description will be given with reference to FIG. 9. For example, similar to the above, a plane La and a first straight line Lb are assumed. Also, in a cross-sectional view of the concave inner wall portion 52, a third straight line Ld that passes through a representative point of the inner wall lower edge portion 52a of the concave inner wall portion 52 and is orthogonal to the plane La is assumed. Here, the third straight line Ld is displaced outward with respect to the first straight line Lb. That is, the concave inner wall portion 52 is inclined such that the inner wall lower edge portion 52a is displaced outward more than the inner wall upper edge portion 52b. The distance dx between the third straight line Ld and the first straight line Lb can be grasped as a value indicating the degree of inclination. The distance dx is, for example, greater than 0 mm and 1 mm or less. Also, the distance dx may be 0.1 mm to 0.8 mm, or may be 0.2 mm to 0.6 mm. Also, assuming that the inner wall lower edge portion 52a and the inner wall upper edge portion 52b are arranged on the same straight line in the vertical direction, the vertical distance between the inner wall lower edge portion 52a and the inner wall upper edge portion 52b is, for example, 1 mm to 8 mm or less. Also, this vertical distance may be 1.5 mm to 7 mm, or may be 2 mm to 6 mm.

[0051] When the opening M is closed by the lid body 3, the concave inner wall portion 52 and the convex outer wall portion 74 are arranged to overlap. At least one of the concave inner wall portion 52 and the convex outer wall portion 74 is provided with convexly bent corners 11a, 11b, 11c, 11d. This convex shape means a state of protruding from one to the other in the overlapping concave inner wall portion 52 and convex outer wall portion 74. The corners 11a to 11d are each provided so as to be continuous along the entire circumference of the opening M, forming a closed-loop ridge line.

[0052] Of the concave-side inner wall portion 52 and the convex-side outer wall portion 74, on one side where the corner portions 11a to 11d are provided, on the other side, corner receiving portions 12a, 12b, 12c, and 12d that are in contact with the corner portions 11a to 11d are provided. The corner receiving portions 12a to 12d are each provided so as to be continuous along the entire circumference of the opening M, and are in contact with the corner portions 11a to 11d over the entire circumference of the opening M. The corner receiving portions 12a to 12d may be in a valley shape that is recessed and bent so as to be able to receive the convex corner portions 11a to 11d, or may be in a flat shape that is not bent, that is, a flat shape with a straight cross-section without bending.

[0053] Specifically, the concave-side inner wall portion 52 includes a plurality of corner portions 11a, 11b and a plurality of corner receiving portions 12a, 12b. The concave-side inner wall portion 52 includes a first corner portion 11a provided at the inner wall upper edge portion 52b and a second corner portion 11b provided between the inner wall upper edge portion 52b and the inner wall lower edge portion 52a. Further, the concave-side inner wall portion 52 includes a first corner receiving portion 12a provided at the inner wall lower edge portion 52a and a second corner receiving portion 12b provided between the inner wall lower edge portion 52a and the inner wall upper edge portion 52b. Also, the first corner portion 11a and the second corner portion 11b are provided at positions closer to the upper end portion 54 than the first corner receiving portion 12a and the second corner receiving portion 12b.

[0054] The convex-side outer wall portion 74 includes a plurality of corner portions 11c, 11d and a plurality of corner receiving portions 12c, 12d. The convex-side outer wall portion 74 includes one peripheral edge connected to the chamfered portion 73 and the other peripheral edge connected to the convex inclined portion 75. One peripheral edge is at a position closer to the fitting end portion 72 than the other peripheral edge. And the convex-side outer wall portion 74 includes a third corner portion 11c provided at one peripheral edge and a fourth corner portion 11d provided between one peripheral edge and the other peripheral edge. Further, the convex-side outer wall portion 74 includes a third corner receiving portion 12c provided at the other peripheral edge and a fourth corner receiving portion 12d provided between one peripheral edge and the other peripheral edge. Also, the third corner portion 11c and the fourth corner portion 11d are provided at positions closer to the fitting end portion 72 than the third corner receiving portion 12c and the fourth corner receiving portion 12d.

[0055] In a state where the protruding strip portion 7 is fitted inside the opening wall 5, the first corner portion 11a and the second corner portion 11b of the concave inner wall portion 52 are in contact with the third corner receiving portion 12c and the fourth corner receiving portion 12d of the convex outer wall portion 74, respectively. Also, the third corner portion 11c and the fourth corner portion 11d of the convex outer wall portion 74 are in contact with the first corner receiving portion 12a and the second corner receiving portion 12b of the concave inner wall portion 52, respectively. Here, the first corner portion 11a and the second corner portion 11b of the concave inner wall portion 52 are provided at positions closer to the upper end portion 54 than the third corner portion 11c and the fourth corner portion 11d of the convex outer wall portion 74.

[0056] Next, with reference to FIGS. 1 to 4, a structure in which the flange portion 8 and the flange receiving portion 6 are engaged will be described. The flange receiving portion 6 includes a protective wall portion 65 erected from the support seat portion 61. The protective wall portion 65 is provided along the outer peripheral edge 6a of the flange receiving portion 6, but is partially missing to form a relief portion 65a.

[0057] The location where the relief portion 65a is formed will be specifically described. The support seat portion 61 includes a portion (opposing portion) disposed to oppose the hinge portion 4 so as to sandwich the opening M, and relief portions 65a are formed at both ends of the opposing portion. Note that the relief portion 65a may be provided at an intermediate portion instead of at the end of the opposing portion.

[0058] The support seat portion 61 includes a support extension portion 61a that protrudes outward so as to correspond to the relief portion 65a where the protective wall portion 65 is missing. A recess 61b is formed in the support extension portion 61a to form a gap with respect to the placed flange portion 8.

[0059] The flange portion 8 includes a main placement portion 81 placed on the support seat portion 61 and a grip piece 85 protruding from the main placement portion 81. When the main placement portion 81 is placed on the support seat portion 61, it fits inside the barrier portion 65 so as to avoid the barrier portion 65. The contour line of the main placement portion 81 substantially corresponds to the contour line 8a of the flange portion 8, and the barrier portion 65 extends along the contour line 8a of the flange portion 8. Further, the barrier portion 65 is provided along the outer peripheral edge 6a of the flange receiving portion 6, and the contour line 8a (the contour line of the main placement portion 81) of the flange portion 8 recedes inward closer to the opening M than the outer peripheral edge 6a of the flange receiving portion 6.

[0060] The grip piece 85 is provided so as to fit into a relief portion 65a where the barrier portion 65 is missing when the flange portion 8 is placed on the flange receiving portion 6. The grip piece 85 is placed on the support extension portion 61a of the flange receiving portion 6. The support extension portion 61a is provided with a recess 61b for facilitating gripping of the grip piece 85. The contour line of the grip piece 85 recedes inward closer to the opening M than the outer peripheral edge of the flange receiving portion 6.

[0061] Next, a container manufacturing method for manufacturing the container 1 will be described. The container 1 is made of a synthetic resin sheet and is manufactured by vacuum forming using a mold 102 (see FIG. 10). As the synthetic resin that is the material of the container 1, it is preferable to use a transparent synthetic resin so that the contents inside the container 1 can be visually confirmed. Examples of the transparent synthetic resin include polystyrene-based, polyethylene-based, polypropylene-based, and polyester-based synthetic resins.

[0062] Further, it is preferable that the synthetic resin sheet used for the container 1 is a stretched sheet manufactured by stretching the synthetic resin so that the molecules are oriented, in terms of the mechanical strength of the formed container 1. Also, the biaxially stretched sheet is more preferable than the uniaxially stretched sheet in terms of the balance of physical properties. In particular, the biaxially stretched sheet of polystyrene-based resin has well-balanced performance in terms of rigidity, heat resistance, transparency, environmental properties, and processability, and is suitable as the material of the container 1.

[0063] Referring to FIGS. 10, 11 and 12, the molding machine 100 will be described. The molding machine 100 is provided with a mold 102 (vacuum molding die) for molding a synthetic resin sheet (hereinafter referred to as "sheet material S") into a desired shape.

[0064] As shown in FIG. 10, the mold 102 is provided with a cavity 105 that adheres to the sheet material S to form the container 1. The cavity 105 is an uneven surface having a shape that follows the inner surface shape (inner side surface shape) for accommodating the food F or the outer surface shape (appearance shape) on the opposite side in the unfolded container 1. In the present embodiment, the mold 102 having an uneven surface following the appearance shape will be described as an example. Note that in FIG. 10(b), the unfolded container 1 is shown in a state where it is turned upside down.

[0065] The cavity 105 includes a flat surface, a curved surface, or bent convex and concave portions following the appearance shape of the container body 2, and includes a main body forming portion 120 capable of forming the container body 2, a lid forming portion 130 capable of forming the lid body 3, and a hinge forming portion 140 capable of forming the hinge portion 4.

[0066] The main body forming portion 120 includes an uneven surface following the appearance shape of the opening wall 5, and includes an opening wall forming portion 150 capable of forming the opening wall 5 by adhering the sheet material S to the uneven surface. The lid forming portion 130 includes an uneven surface following the appearance shape of the ridge portion 7, and includes a ridge forming portion 170 capable of forming the ridge portion 7 by adhering the sheet material S to the uneven surface.

[0067] The opening wall forming portion 150 includes an upper end forming portion 154 and a concave-side inner wall forming portion 152. The upper end forming portion 154 has an uneven surface that follows the outer shape of the upper end portion 54 of the opening wall 5, and the upper end portion 54 can be formed by bringing the sheet material S into close contact with the uneven surface. The concave-side inner wall forming portion 152 has an uneven surface that follows the outer shape of the concave-side inner wall portion 52 of the opening wall 5, and the concave-side inner wall portion 52 can be formed by bringing the sheet material S into close contact with the uneven surface. Here, the concave-side inner wall portion 52 is inclined so as to oppose the restoring force of the hinge portion 4. For example, the inner wall lower edge portion 52a is inclined such that the inner diameter IR of the inner region expands more than the inner wall upper edge portion 52b. The concave-side inner wall forming portion 152 has an uneven surface corresponding to this inclination.

[0068] Further, the ridge forming portion 170 includes a convex-side outer wall forming portion 174. The convex-side outer wall forming portion 174 has an uneven surface that follows the outer shape of the convex-side outer wall portion 74 of the lid body 3, and the convex-side outer wall portion 74 can be formed by bringing the sheet material S into close contact with the uneven surface.

[0069] At least one of the concave-side inner wall forming portion 152 and the convex-side outer wall forming portion 174 has an uneven surface that follows the outer shape of the corner portions 11a to 11d, and the corner portions 11a to 11d can be formed by bringing the sheet material S into close contact with the uneven surface. The other of the concave-side inner wall forming portion 152 and the convex-side outer wall forming portion 174 has an uneven surface that follows the outer shape of the corner receiving portions 12a to 12d, and the corner receiving portions 12a to 12d can be formed by bringing the sheet material S into close contact with the uneven surface.

[0070] For example, the concave-side inner wall forming portion 152 according to the present embodiment can form the corner portions 11a and 11b at a plurality of locations (two locations) on the concave-side inner wall portion 52, and the convex-side outer wall forming portion 174 can form the corner receiving portions 12c and 12d at a plurality of locations (two locations) on the convex-side outer wall portion 74 corresponding to the corner portions 11a and 11b of the concave-side inner wall portion 52. Further, the convex-side outer wall forming portion 174 can form the corner portions 11c and 11d at a plurality of locations (two locations) on the convex-side outer wall portion 74, and the concave-side inner wall forming portion 152 can form the corner receiving portions 12a and 12b at a plurality of locations (two locations) on the concave-side inner wall portion 52 corresponding to the corner portions 11c and 11d of the convex-side outer wall portion 74. That is, both the concave-side inner wall forming portion 152 and the convex-side outer wall forming portion 174 can form single or a plurality of corner portions 11a to 11d, and can also form single or a plurality of corner receiving portions 12a to 12d.

[0071] Further, the opening wall forming portion 150 has an uneven surface following the external shape of the concave-side inclined portion 53, and the concave-side inclined portion 53 can be formed by bringing the sheet material S into close contact with the uneven surface. Also, the lid body forming portion 130 has an uneven surface following the external shape of the convex-side inclined portion 75, and the convex-side inclined portion 75 can be formed by bringing the sheet material S into close contact with the uneven surface.

[0072] As shown in FIGS. 11 and 12, the molding machine 100 includes, for example, a hot plate 101 (heating portion) for heating the sheet material S, a mold 102 (vacuum molding die) disposed opposite to the hot plate 101 so as to sandwich the conveyance path of the sheet material S, a movable device 103 (mold moving portion) for moving the mold 102 to approach and separate from the sheet material S, a vacuum device (suction portion) for communicating and sucking into the cavity 105 of the mold 102, and a conveyance device (sheet conveyance portion) for conveying the sheet material S. Hereinafter, a method (first method) for manufacturing the container 1 using the molding machine 100 will be described.

[0073] The first method is a method called hot plate molding and is an example of vacuum molding. The molding machine 100 used in hot plate molding has the mold 102 and the hot plate 101 disposed opposite to each other so as to sandwich the conveyance path of the sheet material S. Hot plate molding has the advantage that the sheet material S can be efficiently heated during molding.

[0074] Figure (a) of FIG. 11 shows the preparation step (first step). In the preparation step, the conveying device conveys the unprocessed portion of the sheet material S to a predetermined position. This predetermined position is the position between the mold 102 and the hot plate 101. At the predetermined position, one surface of the sheet material S faces the cavity 105 of the mold 102.

[0075] Next, an installation step (second step) of installing the mold 102 on the sheet material S is performed. Figure (b) of FIG. 11 shows the installation step. In the installation step, the movable device 103 moves the mold 102 closer to the sheet material S and brings it into contact in a state where the cavity 105 faces the sheet material S. The sheet material S is heated by the hot plate 101 from the surface opposite to the surface facing the cavity 105 and is softened to the extent that it can be formed.

[0076] Next, a forming step (third step) of sucking and forming the inside of the cavity 105 is performed. Figure (a) of FIG. 12 shows the forming step. In the forming step, the vacuum device is driven to suck the inside of the cavity 105 with respect to the sheet material S in a heated state. As a result, the sheet material S is deformed to follow the shape of the cavity 105 and becomes the container 1.

[0077] Next, a separation step (fourth step) of separating the container 1 from the mold 102 is performed. Figure (b) of FIG. 12 shows the separation step. In the separation step, the heating state by the hot plate 101 is released. Further, while blowing air to pull the container 1 away from the mold 102, the mold 102 is moved in a direction away from the container 1. As a result, the formed sheet material S of the container 1 is separated from the mold 102.

[0078] Next, a finishing step is performed. In the finishing step, the conveying device conveys the sheet material S on which the forming of the container 1 is completed to the finishing device. The finishing device performs finishing processes such as cutting the sheet material S for each container 1. As a result, a plurality of containers 1 are completed (fifth step).

[0079] Next, with reference to FIGS. 13 and 14, a method for manufacturing the container 1 using the molding machine 200 (second method) will be described.

[0080] The molding machine 200 includes a plurality of heaters 201A, 201B (heating units), a first mold 202A (vacuum molding die) having a cavity 205, a first movable device 203A (mold moving unit) for moving the first mold 202A to approach and separate from the sheet material S, a second mold 202B having a plug 206, a second movable device 203B (mold moving unit) for moving the second mold 202B to approach and separate from the sheet material S, a vacuum device (suction unit) for communicating and sucking into the cavity 205 of the mold 102, and a conveying device (sheet conveying unit) for conveying the sheet material S. Note that the first mold 202A and the second mold 202B are arranged to face each other with the conveying path of the sheet material S therebetween.

[0081] FIG. 13(a) is a view showing a preparation step (first step) of conveying the sheet material S to a predetermined position. The plurality of heaters 201A, 201B are arranged so as to sandwich the conveying path of the sheet material S. Further, the plurality of heaters 201A, 201B are arranged upstream of the first mold 202A and the second mold 202B in the conveying direction of the sheet material S. In the preparation step, the conveying device conveys the unprocessed portion of the sheet material S to a predetermined position. This predetermined position is the position between the first mold 202A and the second mold 202B. At the predetermined position, one surface of the sheet material S faces the cavity 205 of the first mold 202A, and the other surface faces the plug 206 of the second mold 202B. Note that the sheet material S is heated by the plurality of heaters 201A, 201B during conveyance to a predetermined position, softened to a degree that it can be molded, and reaches the predetermined position before the softened state is eliminated.

[0082] Next, an installation step (second step) of installing the first mold 202A and the second mold 202B on the sheet material S is performed. The diagram (b) of FIG. 13 is a diagram showing the installation step. In the installation step, the first movable device 203A moves the first mold 202A closer to the sheet material S and brings it into contact in a state where the cavity 205 faces the sheet material S. Further, the second movable device 203B moves the second mold 202B closer to the sheet material S and brings it into contact in a state where the plug 206 faces the sheet material S. The sheet material S is softened to such an extent that it can be molded.

[0083] Next, a molding step (third step) of sucking and molding the inside of the cavity 205 is performed. The diagram (a) of FIG. 14 is a diagram showing the molding step. In the molding step, for the softened sheet material S, a vacuum device is driven to suck the inside of the cavity 205. Further, at least one of the first movable device 203A and the second movable device 203B relatively approaches the first mold 202A and the second mold 202B so that the plug 206 fits into the cavity 205 and functions to assist in vacuum molding. As a result, the sheet material S is deformed to follow the shape of the cavity 205 and becomes the container 1. In the second direction, since the plug 206 assists in vacuum molding, it is advantageous, for example, when molding the container 1 using a sheet material S with a large thickness.

[0084] Next, a separation step (fourth step) of separating the container 1 from the first mold 202A and the second mold 202B is performed. The diagram (b) of FIG. 14 is a diagram showing the separation step. In the separation step, air is blown to pull the container 1 away from the first mold 202A and the second mold 202B. Further, at least one of the first movable device 203A and the second movable device 203B relatively separates the first mold 202A and the second mold 202B. As a result, the sheet material S on which the container 1 is molded is separated from the first mold 202A and the second mold 202B.

[0085] Next, a finishing process is performed. In the finishing process, the conveying device conveys the sheet material S for which the molding of the container 1 has been completed to the finishing device. The finishing device performs finishing processes such as cutting the sheet material S for each container 1. As a result, a plurality of containers 1 are completed (the fifth step).

[0086] Next, the operation and effects of the container 1 according to the above-described embodiment will be described. The lid 3 of the container 1 is connected to the container body 2 via the hinge portion 4. The lid 3 is attached so as to close the opening M of the container body 2 while bending the hinge portion 4. The container body 2 includes an opening wall 5, and the opening wall 5 includes a concave inner wall portion 52. The lid 3 includes a protruding strip portion 7 that is fitted inside the opening wall 5, and the protruding strip portion 7 includes a convex outer wall portion 74 that overlaps the concave inner wall portion 52. At least one of the concave inner wall portion 52 and the convex outer wall portion 74 is provided with corner portions 11a to 11d, and the other is provided with corner receiving portions 12a to 12d that contact the corner portions 11a to 11d.

[0087] The corner portions 11a to 11d form a contact area that continuously closes over the entire circumference of the opening M by contacting the corner receiving portions 12a to 12d, and this contact area serves as a weir to prevent liquid leakage and the like. Further, the hinge portion 4 that connects the lid 3 and the container body 2 is elastically deformable, and a restoring force of the hinge portion 4 acts in the opening direction on the lid 3 in the closed state. The concave inner wall portion 52 of the opening wall 5 is inclined so as to oppose the restoring force of the hinge portion 4, and the convex outer wall portion 74 of the protruding strip portion 7 is strongly pressed against the concave inner wall portion 52 by the repulsion of the concave inner wall portion 52 that opposes the restoring force. As a result, the corner portions 11a to 11d and the contact area in contact with the corner portions 11a to 11d are also firmly and stably maintained, and the sealing performance in the state where the container body 2 is closed by the lid 3 is improved.

[0088] Also, the concave inner wall portion 52 of the container 1 is inclined such that the inner wall lower edge portion 52a has a larger inner diameter IR in the inner region than the inner wall upper edge portion 52b. Due to this inclination, the concave inner wall portion 52 comes into contact with the convex outer wall portion 74 against the restoring force of the hinge portion 4.

[0089] In addition, in the container 1, corner portions 11a and 11b are provided on the inner wall portion 52 on the concave side, and corner portions 11c and 11d are also provided on the outer wall portion 74 on the convex side. That is, by providing the corner portions 11a to 11d on both the inner wall portion 52 on the concave side and the outer wall portion 74 on the convex side, the sealing performance can be enhanced.

[0090] In addition, in the container 1, in a state where the protruding strip portion 7 is fitted inside the opening wall 5, the corner portions 11a and 11b of the inner wall portion 52 on the concave side are provided at positions closer to the upper end portion 54 than the corner portions 11c and 11d of the outer wall portion 74 on the convex side. When the protruding strip portion 7 is fitted inside the opening wall 5, the opening wall 5 is less likely to deform, and the corner portions 11a and 11b of the inner wall portion 52 on the concave side of the opening wall 5 have higher shape stability than the corner portions 11c and 11d of the outer wall portion 74 on the convex side of the protruding strip portion 7. As a result, even if the liquid exceeds the corner portions 11c and 11d of the outer wall portion 74 on the convex side, the liquid can be accurately blocked by the corner portions 11a and 11b of the inner wall portion 52 on the concave side.

[0091] In addition, the container 1 has an opening wall 5 provided with a concave inclined portion 53, and the protruding strip portion 7 is provided with a convex inclined portion 75 overlapping the concave inclined portion 53. When the concave inclined portion 53 and the convex inclined portion 75 come into contact, the sealing performance is further enhanced.

[0092] In addition, by vacuum forming using the above-described molds 102 and 202A, a container 1 can be manufactured in which the sealing performance in a state where the container body 2 is closed by the lid body 3 is improved.

[0093] The present invention is not limited to the above-described embodiments. For example, in the above-described embodiments, a plurality of corner portions are provided on the inner wall portion on the concave side, and a plurality of corner portions are also provided on the outer wall portion on the convex side. However, a form in which a single corner portion is provided on each of the inner wall portion on the concave side and the outer wall portion on the convex side, and a single corner receiving portion is provided on each of the inner wall portion on the concave side and the outer wall portion on the convex side may also be used. Further, a form in which a single corner portion is provided on one of the inner wall portion on the concave side and the outer wall portion on the convex side, and a single corner receiving portion is provided on the other of the inner wall portion on the concave side and the outer wall portion on the convex side may also be used. In addition, the corner receiving portion is not limited to a valley shape, and may be a flat shape, or a form in which a valley-shaped corner receiving portion and a flat-shaped corner receiving portion are mixed in one food packaging container may also be used.

[0094] In addition, the vacuum forming mold is not limited to being made of metal, and a forming mold including other materials or the like may be used. Further, the method for manufacturing the food packaging container may be vacuum forming, and for example, methods capable of thermoforming a sheet material such as pressure air forming, vacuum pressure air forming, and double-sided vacuum forming are widely included.

Description of Reference Numerals

[0095] 1... container (food packaging container), 2... container body, 3... lid body, 4... hinge portion, 5... opening wall, 7... rib portion, 11a to 11d... corner portions, 12a to 12d... corner receiving portions, 52... concave side inner wall portion, 52a... inner wall lower edge portion, 52b... inner wall upper edge portion, 53... concave side inclined portion, 54... upper end portion, 74... convex side outer wall portion, 75... convex side inclined portion, 102... mold (vacuum forming mold), 202... first mold (vacuum forming mold), 205... cavity, 120... main body forming portion, 130... lid body forming portion, 140... hinge forming portion, 150... opening wall forming portion, 154... upper end forming portion, 152... concave side inner wall forming portion, 174... convex side outer wall forming portion, F... food, M... opening, IR... inner diameter of the inner region.

Claims

1. A food packaging container for containing food, comprising: a container body having an opening for taking in and out the food; a lid for closing the opening; a hinge portion that is elastically deformable and connects the container body and the lid so as to be openable and closable; the container body includes an opening wall provided along the outer periphery of the opening; the lid includes a protrusion portion that is fitted into the opening wall; the opening wall includes: an upper end portion surrounding the opening; a concave inner wall portion disposed on the inner peripheral side of the upper end portion and inclined so as to oppose the restoring force of the hinge portion; a flange receiving portion that extends along the outer periphery of the upper end portion and is provided so as to protrude outward from the upper end portion; a protective wall portion provided along the outer peripheral edge of the flange receiving portion; the protrusion portion includes: a convex outer wall portion provided so as to overlap the concave inner wall portion; a flange portion that extends along the outer periphery of the convex outer wall portion and is placed on the flange receiving portion so as to be received inside the protective wall portion; the concave inner wall portion includes a first corner portion and a second corner portion that are convexly bent and continuous along the entire circumference of the opening; the convex outer wall portion includes a first corner receiving portion that receives and contacts the first corner portion, a second corner receiving portion that receives and contacts the second corner portion, and a corner portion that is convexly bent and continuous along the entire circumference of the opening; the concave inner wall portion includes a corner receiving portion that receives and contacts the corner portion of the convex outer wall portion; In a state where the protrusion portion is fitted into the opening wall, the first corner portion and the second corner portion are provided at a position closer to the upper end portion than the corner portion of the convex outer wall portion, and the first corner portion is disposed between the upper end portion and the second corner portion. A food packaging container.

2. The opening wall includes a concave inclined portion provided between the upper end portion and the concave inner wall portion and inclined with respect to the concave inner wall portion; The protrusion portion includes a convex inclined portion inclined with respect to the convex outer wall portion so as to overlap the concave inclined portion. The food packaging container according to claim 1.

3. A vacuum forming mold for manufacturing a food packaging container in which the container body and the lid according to claim 1 or 2 are connected so as to be openable and closable by a hinge portion, comprising: a cavity capable of forming the food packaging container in close contact with a sheet material. The cavity includes a main body forming part capable of forming the container main body, a lid forming part capable of forming the lid body, and a hinge forming part capable of forming the hinge part. The main body forming part includes an opening wall forming part capable of forming an opening wall provided along the outer periphery of the opening of the container main body. The lid forming part includes a ridge forming part capable of forming a ridge part that is fitted inside the opening wall, and is a vacuum forming mold.

4. In a container manufacturing method for manufacturing a food packaging container by vacuum forming using the vacuum forming mold according to Claim 3, the vacuum forming mold is brought into contact with the sheet material so that the cavity faces the sheet material. With the sheet material in a heated state, the sheet material is brought into close contact with the cavity by sucking the inside of the cavity to form the food packaging container. A container manufacturing method in which heating of the food packaging container is released and the food packaging container is detached from the vacuum forming mold.

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