Fitting structure for packaging containers, packaging containers

Abstract

To provide a fitting structure for a packaging container and a packaging container equipped with this fitting structure, which maintains the fitting force specified in the design specifications by accommodating the increase in outer diameter due to expansion and decrease in outer diameter due to contraction that occur when the packaging container is used, as well as the increase in outer diameter due to expansion and decrease in outer diameter due to contraction that occur during the molding of the resin sheet in the manufacturing process, thereby improving the freedom of material selection for the container body and lid, and / or making it easier to relax the manufacturing conditions for the container body and lid. [Solution] With the lid N attached to the container body M, the body fitting portion 1 and the lid fitting portion 2 are fitted together in a direction that connects the inside and outside of the packaging container.

Description

[Technical Field]

[0001] The present invention relates to a fitting structure for a packaging container that packages contents such as food, and to a packaging container provided with the fitting structure. [Background Art]

[0002] Conventionally, a packaging container for packaging food sold at retail stores such as supermarkets and convenience stores has been provided with a container body that accommodates the food and a lid attached to the container body. The lid closes the opening of the container body in a state where the lid is fitted to the container body. When the container body is made of a resin sheet, the container body shrinks more than the lid due to heating in a heating cooking appliance, and the fitted state may become unstable.

[0003] For example, Patent Document 1 discloses a structure in which, before shrinkage of the container body, the flange portion of the container body is fitted from the inner side of the flange portion of the lid, and after shrinkage of the container body, the flange portion of the container body is fitted from the outer side of the flange portion of the lid (see FIGS. 8 and 9). This structure was expected to provide the effect that the lid hermetically closes the opening of the container body before and after shrinkage of the container body. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2020-90290 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] However, in the structure disclosed in Patent Document 1, a state occurs where the flange portion of the container body and the flange portion of the lid are not fitted together between the start and end of the contraction of the container body. This is because, from the start of the contraction, the flange portion of the container body, which was fitted to the flange portion of the lid from the inside, shifts in the direction of the contraction of the container body, and the flange portion of the container body does not fit to the flange portion of the lid from the outside until the end of the contraction.

[0006] Furthermore, in the structure disclosed in Patent Document 1, if the container body or lid expands or contracts during storage or use as a food container, for example, there is a risk that the flange portion of the container body and the flange portion of the lid may not be properly fitted together.

[0007] Furthermore, if different materials are used for the container body, such as an opaque, heat-resistant material for the container itself and a transparent, less heat-resistant material for the lid, the expansion and contraction rates of the container body and the lid may differ. In addition, typical packaging containers are manufactured by heating a flat resin sheet produced by extrusion, shaping it in a mold, and then cooling it. However, the heating and cooling of the resin sheet can cause expansion and contraction.

[0008] Therefore, when the container body and lid were manufactured separately, considerable effort was required to adjust production conditions to ensure that the container body and lid maintained the desired fastening force when closed, taking into account the expansion and contraction rates due to the difference in materials between the container body and lid, as well as the expansion and contraction of the resin sheet due to heating and cooling. In other words, the inventor concluded that a fitting structure between the container body and lid was necessary to accommodate the increase in outer diameter due to expansion and the decrease in outer diameter due to contraction.

[0009] Therefore, the object of the present invention is to provide a fitting structure for a packaging container and a packaging container equipped with this fitting structure, which maintains the fitting force specified in the design specifications in response to the increase in outer diameter due to expansion and decrease in outer diameter due to contraction that occurs when the packaging container is used, as well as the increase in outer diameter due to expansion and decrease in outer diameter due to contraction that occurs during the molding of the resin sheet in the manufacturing process, thereby improving the degree of freedom in selecting materials for the container body and lid, and / or making it easier to relax the manufacturing conditions for the container body and lid. [Means for solving the problem]

[0010] In other words, the present invention relates to a fitting structure for a packaging container comprising a container body and a lid, characterized in that the body fitting portion of the container body and the lid fitting portion of the lid are fitted together along a direction connecting the inside and outside of the packaging container.

[0011] Furthermore, it is desirable that the main body fitting portion and the lid fitting portion be positioned radially from a predetermined point on the packaging container.

[0012] Furthermore, the main body fitting portion and the lid fitting portion are fitted together, with one having a fitting under portion and the other having a fitting protrusion, and it is desirable that the fitting under portion and the fitting protrusion extend radially from a predetermined point on the packaging container.

[0013] Furthermore, it is desirable that the container body has a body flange portion, the lid has a lid flange portion facing the body flange portion, the body fitting portion is formed in a convex shape toward the lid flange portion, and the lid fitting portion is formed in a concave shape capable of accommodating the body fitting portion.

[0014] Furthermore, it is desirable that the container body has a body flange portion, the lid has a lid flange portion facing the flange portion, the lid fitting portion is formed in a convex shape toward the body flange portion, and the body fitting portion is formed in a concave shape so as to accommodate the lid fitting portion.

[0015] Preferably, the main body fitting portion is located at a corner of the main body flange portion in plan view, and the lid body fitting portion is located at a corner of the lid body flange portion in plan view.

[0016] Preferably, the container body is made of a resin material containing starch.

[0017] Further, the present invention is characterized by being a packaging container provided with the above fitting structure.

Effect of the Invention

[0018] According to the present invention, by maintaining the fitting force according to design specifications in response to both the increase in outer diameter due to expansion and the decrease in outer diameter due to shrinkage that occur when the packaging container is used, as well as the increase in outer diameter due to expansion and the decrease in outer diameter due to shrinkage that occur during molding of the resin sheet in the manufacturing process, the effect of easily improving the degree of freedom in material selection for the container body and the lid and / or relaxing the manufacturing conditions for the container body and the lid can be expected.

Brief Description of Drawings

[0019] [Figure 1] (a) is a planar perspective view of a lid, and (b) is a planar perspective view of a container body, of a packaging container provided with a fitting structure according to an embodiment of the present invention. [Figure 2] (a) is a plan view of the lid, and (b) is a plan view of the container body. [Figure 3] (a) is a bottom perspective view of the lid, and (b) is a bottom perspective view of the container body. [Figure 4] (a) is a partially enlarged planar perspective view of the lid, and (b) is a partially enlarged planar perspective view of the container body. [Figure 5] (a) is a partially enlarged planar perspective view of the lid, and (b) is a partially enlarged planar perspective view of the container body. [Figure 6] (a) is a partially enlarged bottom perspective view of the lid, and (b) is a partially enlarged planar perspective view of the container body. [Figure 7] (a) is a planar perspective view and (b) is a side perspective view showing a state where the lid is attached to the container body. [Figure 8](a) is a plan view, (b) is a front view, and (c) is a left side view of the above state. [Figure 9] An explanatory diagram showing the expansion direction and contraction direction of the container body and the lid body in the above state, and another example of the fitting structure corresponding to the above directions. MODE FOR CARRYING OUT THE INVENTION

[0020] Hereinafter, with reference to FIGS. 1 to 9, a packaging container provided with a fitting structure according to an embodiment of the present invention (hereinafter also referred to as "the present packaging container") will be described. In these figures, for a plurality of identical portions, there are also parts where only one portion is numbered. For convenience of explanation, there are also parts where predetermined portions and leader lines are shown by hidden lines (broken lines) or imaginary lines (two-dot chain lines). In the description, terms indicating directions such as upward direction, downward direction, lateral direction, vertical direction, horizontal direction, inward direction, outward direction, center direction and circumferential direction are basically based on the packaging container installed in a normally used orientation, and when other orientations are used as the reference, description will be given as appropriate.

[0021] In the illustration of each figure, "plan view" means viewing the packaging container from above where the projected area is relatively large. With reference to the plan view, "front view" means viewing the packaging container from a predetermined lateral direction, and "end face view" means viewing only the end face of a predetermined cut portion of the packaging container.

[0022] In the present invention, "molding (formed by shaping)" is not limited to the production method, and simply means shaping or being shaped; "molding (formed by mold)" means fitting into a predetermined mold to shape or being shaped. In other words, "molding (formed by shaping)" is an expression that includes "molding (formed by mold)". "External fitting" or "lateral external fitting" refers to a structure in which the fitting portion of the fitting member (e.g., a lid body) is located on the inner side, and the fitting portion of the fitted member (e.g., a container body) is located on the outer side; "internal fitting" refers to a structure in which the fitting portion of the fitting member is located on the outer side, and the fitting portion of the fitted member is located on the inner side.

[0023] <Basic Configuration of the Present Packaging Container> As shown in Figures 1 and 2, this packaging container is used to package one or more types of food products sold in retail stores such as supermarkets, including prepared foods, bento boxes, sushi, sashimi, and salads. It comprises a container body M for containing the food and a lid N attached to the container body M. The packaging container only needs to be small enough to be placed on a display shelf in a retail store, and its dimensions such as length, width, and height are not limited. The container body M and lid N are obtained by molding a predetermined resin sheet. The packaging container may also be formed by integrally molding the container body M and lid N via a hinge (not shown).

[0024] <Overview of Container Body M> As shown in Figures 1(b) and 2(b), the container body M comprises a bottom portion M1 on which food is placed, a side portion M2 formed upward from the circumferential edge of the bottom portion M1, a flange portion M3 formed outward from the opening of the container body M corresponding to the uppermost end of the side portion M2, and a fitting portion 1 formed on the flange portion M3. The bottom portion M1 and the side portion M2 constitute a food storage area for unnumbered food. The storage area has unnumbered partitions for separating food, but it may also be a flat surface without partitions. If the container body M does not have a flange portion M3, the fitting portion 1 may be formed on the bottom portion M1 or the side portion M2. In addition to the main body fitting portion 1, the container body M may have one or more fitting portions (not shown) that have a different structure from the main body fitting portion 1 to achieve internal fitting, external fitting, or side external fitting with the lid N, and these fitting portions may be formed on the main body flange portion M3.

[0025] As shown in Figure 2(b), the container body M is approximately square in plan view, but it may be rectangular, a rectangular shape with pentagons or more, circular, or elliptical. The container body M is not limited in terms of the shape or area of ​​the bottom M1, the vertical height and inclination angle of the side parts M2, the shape and width of the flange part M3 from the innermost to the outermost end, the capacity of the storage section, or the number and shape of the partitions. The storage section may be a box shape with corners or a ball shape without corners. The position, size, range, shape, and dimensions of the body fitting part 1 are not limited as long as it can form a fitted state with the lid fitting part 2.

[0026] The outer diameter of the container body M refers to one or more of the following: the circumferential length of the body flange portion M3, the distance between the outermost ends of the body flange portion M3 in the longitudinal or transverse direction, or the vertical height from the lowest end of the bottom portion M1 to the uppermost end of the body flange portion M3.

[0027] <Capacity of container body M> The container body M may be, for example, 100 to 1800 cc, or 200 to 1000 cc. The side portion M2 of the body may have one or more predetermined steps or reinforcing ribs, or it may be flush without them.

[0028] <Depth of container body M> The depth of the container body M may be 10 mm to 45 mm, preferably 12 mm to 40 mm, more preferably 15 mm to 35 mm, and even more preferably 15 mm to 30 mm. If it is shallower than 10 mm, the size of the food may be limited, and if it is deeper than 45 mm, it may be difficult to remove the food. The depth of the container body M may mean the vertical height from the surface of the bottom M1, which is the lowest part, to the upper end of the main body flange M3, which is the highest part, or the vertical height from the surface of the bottom M1 to the uppermost end of the main body side M2 ​​or the boundary with the main body flange M3.

[0029] <Details of the M2 section on the main body side> As shown in Figures 1(b)-3(b), the main body side portion M2 has main body corner cut portions M21 formed by cutting off the four corners, but it may also have arc-shaped corners formed with a predetermined radius of curvature without having corner cut portions. The circumferential shape of the main body side portion M2 including the main body corner cut portions M21 may or may not correspond to the circumferential shape of the bottom portion M1 or the main body flange portion M3. The main body corner cut portions M21 are formed in a stepped shape with respect to the circumferential direction of the main body side portion M2, and are convex toward the inside of the container body M, but may also be convex toward the outside, and do not have to be formed in the stepped shape described above.

[0030] <Details of the main body flange section M3> As shown in Figures 1(b), 2(b), and 3(b), the main flange portion M3 is formed continuously outward from the uppermost end of the main side portion M2, and has main flange corner portions M31 corresponding to the four corners, a straight main flange portion M32 that is continuous with the main flange corner portions M31, and a main flange step portion M33 formed on the main flange corner portions M31 and the main flange straight portion M32.

[0031] The circumferential shape of the main flange portion M3 is not a straight line like the straight portion M32 of the main flange in a plan view, but can be a curved shape that curves inward towards the container body M, or a curved shape that bulges outward. In the case of a curved shape that curves inward towards the container body M, the corner portion M31 of the main flange becomes relatively convex outward.

[0032] The main flange portion M3 may be flat in the circumferential direction without having the main flange step portion M33. The main flange step portion M33 has the function of ensuring stability when attached to the lid N, preventing leakage of food juices from the inside, and facilitating the attachment and detachment of the lid N. The number of steps in the main flange step portion M33 may be one, two, or three or more. The main flange portion M3 is shown horizontally, but it may also be sloped downwards from the inside to the outside of the container body M, or sloped upwards (not shown).

[0033] <Details of the M33 stepped section of the main flange> As shown in Figure 4(b), the main flange step portion M33 has a first main flange step portion M33a and a second main flange step portion M33b, but the second main flange step portion M33b is not required. The first main flange step portion M33a is formed in a convex and linear shape from the main flange straight portion M32 toward the upper side of the second main flange step portion M33b, but it may also be formed convex toward the lower side or curved. The end of the main flange first step portion M33a in the longitudinal direction is inclined, but may also be perpendicular.

[0034] The second stepped portion M33b of the main flange is formed in a convex shape extending upward from the straight portion M32 of the main flange, and is formed to be continuous with the main flange corner portion M31, extending from the outside of the container body M in the short direction of the first stepped portion M33a of the main flange along the uppermost end of the main body corner cut portion M21.

[0035] <Details of the main body fitting part 1> As shown in Figures 1(b), 2(b), and 3(b), the main body fitting portion 1 only needs to be oriented in a direction that connects the inside and outside of the container body M in a plan view, and may be oriented in the same direction as the virtual diagonals VL1 and VL2 of the main body shown in Figure 2(b). The main body fitting portions 1, 1 located on the virtual diagonals VL1 and VL2 of the main body may be formed symmetrically with respect to their respective diagonals, or they may be formed in different directions. The main body fitting portion 1 is straight in a plan view, but may also be curved, and if it is curved, it may all be curved in the same direction, or all or every two combinations may be curved in different directions.

[0036] The main body fitting portion 1 may be located along a radial direction from a predetermined point on the container body M. For example, it may be located along the virtual diagonal lines VL1 and VL2 of the container body that correspond to the radial direction from the center point Ms of the container body M in the plan view shown in Figure 2(b), but it is sufficient if it is located along a predetermined line that passes through a predetermined point on the packaging container that corresponds to the radial direction.

[0037] The main body fitting portion 1 is formed at all four corners of the container body M in a plan view, but it does not have to be formed at any one corner, for example, nor does it have to be formed at a pair of corners located on the virtual diagonal VL1 or VL2 of the main body as shown in Figure 2(b). The main body fitting portion 1 may be located at places other than the four corners of the container body M in a plan view, for example, on the straight portion M32 of the main body flange, and there may be one or more of them.

[0038] As shown in Figures 4(b), 5(b), and 6(b), the main body fitting portion 1 is formed in a dome shape that is convex upward from the main body flange portion M3 and has a hollow interior, and has main body fitting side portions 11 that are concave from both sides toward the cavity, a main body fitting upper portion 12 located at the uppermost end, a main body fitting tip portion 13 located at the outermost end, and a main body fitting rear end portion 14 located at the innermost end. More precisely, the main body fitting portion 1 is the surface of the dome-shaped portion that faces the lid fitting portion 2.

[0039] The main body fitting portion 1 may be formed in a convex shape extending downward from the main body flange portion M3 (not shown). The main body fitting portion 1 has vertical sides when viewed from the vertical end face in the short direction, but the width between the sides on the lower end side may be wider or narrower than the width between the upper end side, resulting in an inclined shape.

[0040] The main body fitting side portion 11 may be formed in a concave shape toward the cavity from both sides of the main body fitting portion 1. The main body fitting side portion 11 is formed in a linear and horizontal shape in the longitudinal direction of the main body fitting portion 1, and may or may not extend to the main body fitting tip portion 13 or the main body fitting rear end portion 14, and may be inclined so that the main body fitting rear end portion 14 is higher than the main body fitting tip portion 13, or inclined so that the main body fitting tip portion 13 is higher than the main body fitting rear end portion 14. On the other hand, it is preferable that the main body fitting side portion 11 is formed parallel to the expanding direction of the bottom portion M1. The bottom portion M1 is the area with the largest surface area of ​​the container body M, and by forming it in this way, the main body fitting side portion 11 can be slid so as to coincide with the expansion or contraction direction of the bottom portion M1.

[0041] If the container body M is, for example, a square with a length and width of 500 mm, it is preferable that the length of the body fitting side portion 11 is 5 mm or more. If the body fitting side portion 11 is less than 5 mm, when the container body M expands or contracts, the body fitting side portion 11 may not slide enough to fit with the lid fitting side portion 21, and there is a risk that the appropriate fitting force cannot be achieved. If the dimensions of the container body M are different from those described above, the length of the body fitting side portion 11 is molded to be at least the length calculated proportionally.

[0042] There are no particular restrictions on the length of the main body fitting side portion 11, but it is preferably 30 mm or less, and more preferably 20 mm or less, regardless of the size of the container body M. If the main body fitting side portion 11 exceeds 30 mm, the main body fitting portion 1 and the lid fitting portion 2 will be enlarged accordingly, which may impair the aesthetic appearance of the packaging container.

[0043] Both sides (both sides) of the main body fitting portion 1 are parallel, and the main body fitting side portions 11, 11 provided thereon are also parallel. However, if the width of the main body fitting rear end portion 14 side of the ends of both sides of the main body fitting portion 1 is relatively wider and tapered, the main body fitting side portion 11 may also be formed in a tapered shape. Alternatively, the main body fitting side portion 11 may be formed in a tapered shape by relatively decreasing the amount of concavity toward the main body fitting tip portion 13 side of the main body fitting side portion 11. Instead of being formed in a concave shape toward the cavity, the main body fitting side portion 11 may be an adjuster type with protrusions and indentations arranged at predetermined intervals toward the outside of the main body fitting portion 1.

[0044] When the main body fitting portion 1 is tapered, there is no restriction on the angle of the taper on both sides (both sides) of the main body fitting portion 1. However, the difference in position between the sides when it is not tapered (when the width of the main body fitting tip portion 13 and the main body fitting rear end portion 14 are the same) is preferably 10 degrees or less, and more preferably 3 degrees or less. That is, the angle of the taper of the pair of main body fitting side portions 11, 11 is preferably 20 degrees or less, and more preferably 6 degrees or less. This reduces the variation in the amount of recess of the main body fitting side portion 11 from the main body fitting rear end portion 14 toward the main body fitting tip portion 13, and simplifies the shape.

[0045] The distance between the pair of body fitting sides 11, 11 is preferably in the range of 1 mm to 30 mm. More preferably, it is in the range of 7 mm to 13 mm. If they are closer than 1 mm, the width of the body fitting part 1 and the lid fitting part 2 cannot be sufficiently secured, which may affect the fitting operation between the container body M and the lid N. If they are further apart than 30 mm, the width of the body fitting part 1 and the lid fitting part 2 will be wider, which may impair the aesthetic appearance of the packaging container.

[0046] The upper part 12 of the main body fitting is flat, but it may be semi-circular (with a cross-section that curves upwards) or curved. The tip part 13 of the main body fitting is flat and vertical, but it may be curved or inclined. The rear end part 14 of the main body fitting is formed integrally with the main body corner cut part M21 and extends to the bottom part M1, but it may be formed to be continuous with the uppermost end of the main body corner cut part M21, or it may be formed to be located outside the uppermost end of the main body corner cut part M21. In other words, the main body fitting part 1 may be formed like an isolated island at a position separated from other parts within the range of the main body flange corner part M31.

[0047] <Overview of Lid N> As shown in Figures 1(a) and 2(a), the lid N comprises a flat top surface N1, a lid side portion N2 formed downward from the peripheral edge of the top surface N1, a lid flange portion N3 formed outward from the lowest end of the lid side portion N2, and a lid fitting portion 2 formed on the lid flange portion N3. The top surface N1 and the lid side portion N2 constitute the cover portion for unnumbered food items. If the lid N does not have a lid flange portion N3, the lid fitting portion 2 may be formed on the top surface N1 or the lid side portion N2. In addition to the lid fitting portion 2, the lid N may have one or more fitting portions (not shown) that have a different structure from the lid fitting portion 2 to achieve internal fitting, external fitting, or side external fitting.

[0048] As shown in Figure 2(a), the lid N is approximately square in plan view, but it may be rectangular, a rectangular shape with pentagons or more, circular, or elliptical. The shape and area of ​​the top surface N1, the vertical height and inclination angle of the lid side N2, the shape and width of the lid flange N3 from the innermost to the outermost end, and the shape and height of the lid fitting portion 2 are not limited. The cover portion may be a box shape with corners or a ball shape without corners. The position, size, range, shape, and dimensions of the lid fitting portion 2 are not limited as long as it can form a fitted state with the main body fitting portion 1.

[0049] The outer diameter of the cover N refers to one or more of the following: the circumferential length of the cover flange portion N3, the distance between the outermost ends of the cover flange portion N3 in the longitudinal or transverse direction, or the vertical height from the uppermost end of the top surface portion N1 to the lowermost end of the cover flange portion N3.

[0050] <Details of side part N2 of the lid> As shown in Figures 1(a), 2(a), and 3(a), the side portion N2 of the lid has corner-cut portions N21 formed by cutting off the corners of the four corners, but it may also have arc-shaped corners formed with a predetermined radius of curvature without having corner-cut portions. The circumferential shape of the side portion N2 of the lid, including the corner-cut portions N21, may or may not correspond to the circumferential shape of the top portion N1 or the flange portion N3 of the lid. The corner-cut portions N21 of the lid are not formed in a stepped manner with respect to the circumferential direction of the side portion N2 of the lid, but they may be formed in a stepped manner corresponding to the side portion M2 of the main body, and they may be convex toward the inside or outward of the lid N.

[0051] <Details of the lid flange portion N3> As shown in Figures 1(a), 2(a), and 3(a), the lid flange portion N3 is formed continuously outward from the lowest end of the lid side portion N2 and has lid flange corner portions N31 corresponding to the four corners, a straight lid flange straight portion N32 continuous with the lid flange corner portions N31, and a lid flange stepped portion N33 formed on the lid flange straight portion N32. The lid flange portion N3 may have an unnumbered lid flange groove portion between the lowest end of the lid side portion N2 and the lid flange corner portions N31 and the lid flange straight portion N32.

[0052] The circumferential shape of the lid flange portion N3 is not a straight line like the straight portion N32 of the lid flange in a plan view, but can be a curved shape that curves inward towards the lid N, or a curved shape that bulges outward. In the case of a curved shape that curves inward towards the lid N, the corner portion N31 of the lid flange becomes relatively convex outward.

[0053] The lid flange portion N3 may be flat in the circumferential direction without having a lid flange step portion N33. The lid flange step portion N33 has the function of ensuring stability when attached to the container body M, preventing leakage of food juices from the inside, and facilitating the attachment and removal of the lid N. The number of steps in the lid flange step portion N33 may be one or two or more. The lid flange portion N3 is shown horizontally, but it may also be sloped downwards from the inside to the outside of the lid N, or sloped upwards (not shown).

[0054] <Details of the lid flange step portion N33> As shown in Figure 4(a), the cover flange step portion N33 has a first cover flange step portion N33a. The first cover flange step portion N33a is formed in a convex and linear shape upward from the straight portion N32 of the cover flange, but it may also be formed in a convex shape downward or in a curved shape. The end of the first cover flange step portion N33a in the longitudinal direction is inclined, but may also be right-angled.

[0055] <Details of the lid fitting part 2> As shown in Figures 1(a), 2(a), and 3(a), the lid fitting portion 2 only needs to be oriented in a direction that connects the inside and outside of the lid N in a plan view, and may be oriented in the same direction as the virtual diagonals VL3 and VL4 of the lid shown in Figure 2(a). The lid fitting portions 2, 2 located on the virtual diagonals VL3 and VL4 of the lid may be formed symmetrically with respect to their respective diagonals, or they may be formed in different directions. The lid fitting portion 2 is straight in a plan view, but may also be curved, and if it is curved, it may all be curved in the same direction, or all or every combination of two may be curved in different directions.

[0056] The lid fitting portion 2 may be positioned along a radial direction from a predetermined point on the lid N. For example, it may be positioned along virtual diagonal lines VL3 or VL4 of the lid, which correspond to the radial direction from the center point Ns of the lid N in the plan view shown in Figure 2(a), but it is sufficient if it is along a predetermined line that passes through a predetermined point on the packaging container corresponding to the radial direction.

[0057] The cover fitting portions 2 are formed at all four corners of the cover N in a plan view, but they do not have to be formed at any one corner, for example, nor do they have to be formed at a pair of corners located on the virtual diagonal lines VL3 or VL4 of the cover as shown in Figure 2(a). The cover fitting portions 2 may also be located at locations other than the four corners of the cover N in a plan view, for example, on the straight section N32 of the cover flange, and there may be one or more of them.

[0058] As shown in Figures 4(a), 5(a), and 6(a), the lid fitting portion 2 is formed in a dome shape that is convex upward from the lid flange portion N3 and has a hollow interior. It has lid fitting side portions 21 that are convex toward the cavity from both sides, a lid fitting upper portion 22 located at the uppermost end, and a lid fitting tip portion 23 located at the outermost end. More precisely, the lid fitting portion 2 is the surface of the dome-shaped portion that faces the main body fitting portion 1.

[0059] The lid fitting portion 2 may be formed in a convex shape extending downward from the lid flange portion N3 (not shown). The lid fitting portion 2 has vertical sides when viewed from the vertical end face in the short direction, but the width between the sides on the lower end side may be wider or narrower than the width between the upper end side, resulting in an inclined shape. The lid fitting portion 2 is integrally molded with the lid corner cut portion N21 shown in Figure 4(a), but if it is not integrally molded and is located at a distance from the lid corner cut portion N21, it may have an unnumbered lid fitting rear end located at the innermost end.

[0060] The lid fitting side portion 21 may be formed convexly toward the cavity from both sides of the lid fitting portion 2. The lid fitting side portion 21 is formed linearly and horizontally in the longitudinal direction of the lid fitting portion 2, and may or may not reach the lid fitting tip portion 23 or the lid corner portion N21, and may be inclined so that the lid corner portion N21 side is higher than the lid fitting tip portion 23 side, or inclined so that the lid fitting tip portion 23 side is higher than the lid corner portion N21 side. On the other hand, it is preferable that the lid fitting side portion 21 is formed parallel to the expanding direction of the top surface portion N1. The top surface portion N1 is the area with the largest surface area of ​​the lid N, and by forming it in this way, the lid fitting side portion 21 can be slid so as to coincide with the expansion or contraction direction of the top surface portion N1.

[0061] If the lid N is, for example, a square with a length and width of 500 mm, it is preferable that the length of the lid fitting side portion 21 is 5 mm or more. If the length of the lid fitting side portion 21 is less than 5 mm, when the lid N expands or contracts, the length of the lid fitting side portion 21 that slides to fit with the main body fitting side portion 11 may not be sufficient, and the appropriate fitting force may not be achieved. If the dimensions of the lid N are different from those described above, the length of the lid fitting side portion 21 is molded to be at least the length calculated proportionally.

[0062] There are no particular restrictions on the length of the lid fitting side portion 21, but it is preferably 30 mm or less, and more preferably 20 mm or less, regardless of the size of the lid N. If the lid fitting side portion 21 exceeds 30 mm, the main body fitting portion 1 and the lid fitting portion 2 will be enlarged accordingly, which may impair the aesthetic appearance of the packaging container.

[0063] Both sides (both sides) of the lid fitting portion 2 are parallel, and the lid fitting side portions 21, 21 provided thereon are also parallel. However, if the width of the end of both sides of the lid fitting portion 2 on the side of the lid corner cut portion N21 is relatively wider and tapered, the lid fitting side portion 21 may also be formed in a tapered shape. Alternatively, the lid fitting side portion 21 may be formed in a tapered shape by relatively decreasing the amount of protrusion toward the lid fitting tip portion 23. Instead of being formed in a convex shape toward the cavity, the lid fitting side portion 21 may be an adjuster type with protrusions and indentations arranged at predetermined intervals.

[0064] When the lid fitting portion 2 is tapered, there is no restriction on the angle of the taper on both sides (both sides) of the lid fitting portion 2. However, the difference in position between the tapered and non-tapered sides (when the width of the lid fitting tip portion 23 and the width of the side further back are the same) is preferably 10 degrees or less, and more preferably 3 degrees or less. That is, the angle of the taper of the pair of lid fitting side portions 21, 21 is preferably 20 degrees or less, and more preferably 6 degrees or less. This reduces the variation in the amount of protrusion of the lid fitting side portion 21 toward the lid fitting tip portion 23, and simplifies the shape.

[0065] The distance between the pair of lid fitting sides 21, 21 is preferably in the range of 1 mm to 30 mm. More preferably, it is in the range of 7 mm to 13 mm. If they are closer than 1 mm apart, the width of the main body fitting part 1 and the lid fitting part 2 cannot be sufficiently secured, which may affect the fitting operation between the container body M and the lid N. If they are further apart than 30 mm apart, the width of the main body fitting part 1 and the lid fitting part 2 will be wider, which may impair the aesthetic appearance of the packaging container.

[0066] The upper part 22 of the lid fitting is flat, but may be semi-circular (with a cross-section that curves upwards) or curved. The tip 23 of the lid fitting is flat and vertical, but may be curved or inclined. The lid fitting portion 2 may be formed like an isolated island at a position separated from other parts within the range of the lid flange corner N31.

[0067] <Specifications of the resin sheet material, molding method, dimensions, etc. for the container body M and lid N> The material of the resin sheet is not particularly limited and may be polystyrene paper (PSP) made of polystyrene resin, filler-filled polypropylene (PPF), polyester resin such as polyethylene terephthalate, or olefin resin such as polyethylene or polypropylene. It may consist of a single layer or multiple layers, and may be colored, colorless and transparent, or opaque. It may also be made of a heat-resistant material. The resin sheet is used to form the container body M by thermoforming, such as by vacuum forming, hot plate pressure forming, vacuum pressure forming, or double-sided vacuum forming. The surface and / or back surface of the resin sheet may be covered with a resin film. The resin film may consist of a single layer or multiple layers having heat resistance, oil resistance, lamination compatibility with printed layers, gas barrier properties, etc. If the surface of the resin sheet is covered, it may include a printed layer.

[0068] On the other hand, if the resin sheet is obtained by adding a material that has the ability to absorb moisture and oil from food or the ability to absorb water vapor from the atmosphere to a predetermined resin, the effects of the present invention are fully exhibited and are therefore preferable. Examples of such materials include starch, which is preferable from the viewpoint of reducing environmental impact because it is a plant-derived component. In addition, one or more of the following components may be selected as components other than starch: wood-derived fibers, substances with high affinity for water molecules (e.g., nylon 6, nylon 66, etc.), and substances with high water absorption (e.g., polyvinyl alcohol, polyethylene glycol, etc.). Even if the container body M expands by absorbing moisture from the surroundings or moisture, oil, and water vapor from food, the fitting structure of the present invention maintains the fitting state appropriately.

[0069] When the above material is starch, the starch addition rate to the specified resin is preferably 30% by weight or more, which can be expected to reduce the environmental burden, more preferably 50% by weight or more, which can be expected to further reduce the environmental burden, and particularly preferably 60% by weight or less, which can be expected to improve productivity. If it is less than 30% by weight, the proportion of the specified resin increases, making it difficult to expect a reduction in the environmental burden, and if it is more than 60% by weight, the proportion of the specified resin decreases, which makes it easy to lose the flexibility required for the resin sheet, making it difficult to cool and wind the sheet after the extrusion process, and as a result it is difficult to expect an improvement in productivity, and there is also a risk of defects such as tearing and wrinkling of the sheet.

[0070] The resin sheet may be made of foamed resin or non-foamed resin. There are no particular restrictions on the thickness of the resin sheet, but for low-foaming resins with a foaming ratio of 1.5 to 3 times, it should be 0.5 to 3 mm, preferably 1 to 2 mm; for high-foaming resins with a foaming ratio of 5 to 15 times, it should be 1.5 to 5 mm, preferably 2 to 4 mm, more preferably 2.5 to 3.5 mm; and for non-foaming resins, it should be 0.2 to 1.0 mm, preferably 0.23 to 0.65 mm, and even more preferably 0.23 to 0.45 mm. The foaming ratio is calculated by measuring the specific volume (unit: cc / g) of the material before foaming (foaming composition) and the material after foaming (foaming sheet), and dividing the specific volume after foaming by the specific volume before foaming.

[0071] On the other hand, when starch is added, the resin sheet is preferably made of non-foaming polypropylene or polystyrene that does not require transparency (e.g., high-impact polystyrene). Adding starch to a resin sheet raises concerns about reduced transparency and impact on foamability. Polystyrene is a crystalline resin and therefore does not possess transparency at the thickness used for food containers. High-impact polystyrene, on the other hand, has rubber material added and does not require transparency, making it a preferable choice.

[0072] <Specifications of the resin film material, forming method, dimensions, etc. for the container body M and lid N> The resin film may be laminated in the following order from the side furthest from the base material as a resin sheet: for example, a polypropylene resin layer, a printed layer, a dry lamination adhesive layer, a gas barrier layer, a dry lamination adhesive layer, and a polystyrene resin layer. Alternatively, the printed layer and gas barrier layer may be omitted, and they may be laminated with adhesive layers other than the dry lamination adhesive layer, or a polypropylene resin layer, a gas barrier layer, and a polypropylene resin layer may be laminated in this order. In the container body M and lid N shown in Figure 1, the base material is on the outside and the resin film is on the inside (food contact side).

[0073] <Features based on the materials of the container body M and lid N> The container body M and lid N may be prone to expansion or to resistance due to the absorption of water vapor contained in the surrounding atmosphere or moisture and oil generated from the food, and may be prone to contraction or to resistance due to heating by a cooking appliance. For example, a combination of a container body M that is prone to expansion and contraction and a lid N that is prone to contraction and resistance to expansion is also possible. The resin sheet material selected for the container body M and lid N preferably has an expansion rate of 0.1% to 5%, and more preferably 0.1% to 3.5%. Here, the expansion rate is the amount of change in dimensions after the absorption of water vapor or moisture and oil, relative to the dimensions when the resin sheet is molded (shaped) into the container body M and lid N. By setting the range of the expansion rate in this way, the dimensions of the body fitting side 11 and lid fitting side 21 can be shortened, and the impact on the aesthetic appearance of the packaging container can be suppressed. Furthermore, the resin sheet material selected for the container body M and lid N preferably has a shrinkage rate of 0.1% to 5%, and more preferably 0.1% to 3.5%. Here, the shrinkage rate is the amount of change in the product dimensions after the curing period or after further heating in a cooking appliance, relative to the dimensions when the resin sheet is molded (formed) into the container body M and lid N. The curing period is the period after molding (forming) into the container body M and lid N until the changes in product dimensions due to resin crystallization, etc., stabilize. By setting the range of the shrinkage rate in this way, the dimensions of the body fitting side 11 and the lid fitting side 21 can be shortened, and the impact on the aesthetic appearance of the packaging container can be suppressed.

[0074] The expansion and contraction directions of the container body M and lid N may be radial directions that can be expressed in three dimensions (XYZ coordinates) with respect to a predetermined point on the packaging container, or radial directions that can be expressed in two dimensions (XY coordinates) with respect to the same predetermined point in the horizontal direction at a predetermined height.

[0075] The predetermined point on this packaging container may be either a predetermined point on the container body M or a predetermined point on the lid N. The predetermined point on the container body M and the predetermined point on the lid N may or may not coincide, and if they do not coincide, they may be points that overlap vertically. On the other hand, when the container body M is made of a material that is relatively prone to expansion (or contraction) and the lid N is made of a material that is relatively resistant to expansion (or contraction), it is preferable that the predetermined point on the packaging container is a predetermined point on the container body M. The body fitting portion 1 and the lid fitting portion 2 can be designed based on the predetermined point on the container body M, and an appropriate fitting state between the container body M and the lid N can be maintained before and after expansion of the packaging container and during the expansion process (or before and after contraction and during the contraction process).

[0076] The predetermined point on the container body M in a plan view may be the center point Ms of the container body M shown in Figure 2(b), and the predetermined point on the lid N in a plan view may be the center point Ns of the lid N shown in Figure 2(a). Alternatively, it may be a point that maintains a fitted state without being linked to the expansion or contraction of the container body M or lid N when the lid N is attached to the container body M, or a hinge that connects the integrally molded container body M and lid N.

[0077] The expansion and contraction directions of the container body M and lid N correspond to the expansion and contraction directions of the container body M and lid N. If the predetermined points of the packaging container in a plan view are the center point Ms of the container body M and the center point Ns of the lid N, the radial directions from the center points Ms and Ns indicated by the arrows in Figure 9(a) are the directions of expansion and contraction of the container body M and lid N. If the predetermined point is a single point where a location Mp on the container body M and a location Np on the lid N overlap, maintaining a fitted state without being linked to the expansion and contraction of the container body M and lid N due to the fitting of a fitting part (not shown) at a predetermined position on the container body M and a fitting part (not shown) at a predetermined position on the lid N. If the predetermined point is a two-point location where the location Mp on the container body M and the location Np on the lid N overlap due to the fitting of the fitting parts, the radial directions from the two points indicated by the arrows in Figure 9(c) are the directions of expansion and contraction of the container body M and lid N.

[0078] <Characteristics of the fitting state of the container body M and lid N> The fitting state of the container body M and lid N means that the fitting force between the body fitting portion 1 and the lid fitting portion 2 is within the design specifications; in other words, it means that the body fitting portion 1 and the lid fitting portion 2 are not separated and their fitting force is not released.

[0079] The fitted state of the container body M and the lid N is maintained such that when the container body M expands, the body fitting portion 1 slides relative to the lid fitting portion 2 in the direction of expansion of the container body M, when the container body M contracts, the body fitting portion 1 slides relative to the lid fitting portion 2 in the direction of contraction of the container body M, when the lid N expands, the lid fitting portion 2 slides relative to the body fitting portion 1 in the direction of expansion of the lid N, and when the lid N contracts, the lid fitting portion 2 slides relative to the body fitting portion 1 in the direction of contraction of the lid N.

[0080] In other words, when the container body M expands, the main body fitting part 1 slides relative to the lid fitting part 2 in the direction of expansion of the container body M to maintain the fitted state; when the container body M contracts, the main body fitting part 1 slides relative to the lid fitting part 2 in the direction of contraction of the container body M to maintain the fitted state; when the lid N expands, the lid fitting part 2 slides relative to the main body fitting part 1 in the direction of expansion of the lid N to maintain the fitted state; and when the lid N contracts, the lid fitting part 2 slides relative to the main body fitting part 1 in the direction of contraction of the lid N to maintain the fitted state.

[0081] When the container body M and lid N expand, the body fitting portion 1 slides relative to the lid fitting portion 2, or the lid fitting portion 2 slides relative to the body fitting portion 1, according to the degree of expansion of each, and when the container body M and lid N contract, according to the degree of contraction of each, in order to maintain the fitted state. The same applies when the container body M expands and the lid N contracts, when the container body M contracts and the lid N expands, when only the container body M expands or contracts and the dimensions of the lid N do not change, and when only the lid N expands or contracts and the dimensions of the container body M do not change.

[0082] <Details of the container body M with the lid N attached> As shown in Figures 7 and 8, when the lid N is attached to the container body M, the body fitting portion 1 and the lid fitting portion 2 are fitted together in a direction that connects the inside and outside of the packaging container.

[0083] With this configuration, in response to the increase in outer diameter due to expansion and decrease in outer diameter due to contraction that occur when using the packaging container, and the increase in outer diameter due to expansion and decrease in outer diameter due to contraction that occur during the molding of the resin sheet in the manufacturing process, one of the main body fitting part 1 and the lid fitting part 2 can slide, or both can slide past each other, within a predetermined range in the direction connecting the inside and outside of the packaging container. This configuration is expected to maintain the fitting force specified in the design specifications between the main body fitting part 1 and the lid fitting part 2.

[0084] As shown in Figures 4 and 5, in the above state, the lid fitting portion 2 of the lid N is placed over the body fitting portion 1 of the container body M, and the lid fitting side portion 21 is fitted onto the body fitting side portion 11, thereby forming a fitted state between the container body M and the lid N. At this time, the lid flange first stepped portion N33a is placed over the body flange first stepped portion M33a, but since neither the body flange first stepped portion M33a nor the lid flange first stepped portion N33a has a predetermined fitting portion, they do not fit together. In other words, the container body M and the lid N are fitted together in the direction of the body fitting portion 1 and the lid fitting side portion 21 of the lid fitting portion 2, which are formed in the direction of the connection between the inside and outside of the packaging container, so that the body fitting portion 1 and the lid fitting portion 2 slide in the direction in conjunction with the expansion and contraction of the container body M and the lid N.

[0085] As shown in Figures 4 and 5, the longitudinal lengths of the lid fitting portion 2 and the lid fitting portion 21 are longer than the longitudinal lengths of the main body fitting portion 1 and the main body fitting side portion 11. Therefore, the lid fitting portion 2 can be placed over the main body fitting portion 1, and the main body fitting side portion 11 and the lid fitting side portion 21 can slide against each other. The sliding range between the main body fitting side portion 11 and the lid fitting side portion 21 is equal to the longitudinal length of the main body fitting side portion 11. When the main body fitting portion 1 and the lid fitting portion 2 are fitted together, the main body fitting tip portion 13 and the lid fitting tip portion 23 are not in contact but are separated.

[0086] As shown in Figures 2 and 9, the main body fitting portion 1 and the lid fitting portion 2 are located radially from predetermined points on the packaging container. These predetermined points are, for example, the center point Ms of the container body M and the center point Ns of the lid N shown in Figure 9(a), one point where the fitting portion (not shown) on the main body flange corner M31 of the container body M and the fitting portion (not shown) at a predetermined position on the lid N which becomes the lid flange corner N31 overlap, maintaining a fitted state without being linked to the expansion and contraction of the container body M and lid N, as shown in Figure 9(b), and two points where the location Mp of the container body M and the location Np of the lid N overlap, as shown in Figure 9(c).

[0087] With this configuration, the position and orientation of the body fitting portion 1 and the lid fitting portion 2 can be determined according to the expansion and contraction directions of the container body M and the lid N. Therefore, it is expected that a fitting structure using the body fitting portion 1 and the lid fitting portion 2 can be adopted for any packaging container.

[0088] As shown in Figures 4 and 5, the main body fitting portion 1 and the lid fitting portion 2 are fitted together, with a fitting under portion on one side and a fitting protrusion on the other. The fitting under portion and the fitting protrusion extend radially from a predetermined point on the packaging container. The fitting under portion and the fitting protrusion correspond to the main body fitting side portion 11 and the lid fitting side portion 21.

[0089] With this configuration, even if the orientation of the main body fitting portion 1 and the lid fitting portion 2 are not in the direction connecting the inside and outside of the packaging container or radially from a predetermined point on the packaging container, as long as the main body fitting side portion 11 and the lid fitting side portion 21 fit together along the direction connecting the inside and outside of the packaging container and extend radially from a predetermined point on the packaging container, the effect of obtaining a fitting structure by the main body fitting portion 1 and the lid fitting portion 2 can be expected.

[0090] <Supplementary information regarding the correlation between the container body M and the lid N> As shown in Figures 1 and 4, the container body M has a body flange portion M3, and the lid N has a lid flange portion N3 facing the body flange portion M3. The body fitting portion 1 is formed in a convex shape toward the lid flange portion N3, and the lid fitting portion 2 is formed in a concave shape capable of accommodating the body fitting portion 1. Alternatively, although not shown, the lid fitting portion 2 may be formed in a convex shape toward the body flange portion M3, and the body fitting portion 1 may be formed in a concave shape capable of accommodating the lid fitting portion 2. With these configurations, it is expected that the lid N will be easier to attach to the container body M.

[0091] Furthermore, when the lid fitting portion 2 is formed convexly toward the main body flange portion M3, and the main body fitting portion 1 is formed concavely so as to accommodate the lid fitting portion 2, the longitudinal length of the lid fitting portion 2 and the lid fitting side portion 21 is shorter than the longitudinal length of the main body fitting portion 1 and the main body fitting side portion 11. Therefore, the lid fitting portion 2 can be placed over the main body fitting portion 1, and the main body fitting side portion 11 and the lid fitting side portion 21 can slide against each other. The sliding range between the main body fitting side portion 11 and the lid fitting side portion 21 is the longitudinal length of the lid fitting side portion 21. When the main body fitting portion 1 and the lid fitting portion 2 are fitted together, the main body fitting tip portion 13 and the lid fitting tip portion 23 are not in contact but are separated.

[0092] As shown in Figures 1 and 4, the main body fitting portion 1 is located at the main body flange corner M31 in a plan view, and the lid fitting portion 2 is located at the lid flange corner N31 in a plan view. With this configuration, a relatively high fitting force can be obtained against external forces, and therefore, the lid N is less likely to come off the container body M.

[0093] Furthermore, the packaging container shown in this embodiment is not limited to the above-described content, and includes the position, shape, dimensions, and relationships between any part, as long as equivalent effects can be obtained. [Explanation of symbols]

[0094] 1 Main body fitting part 11 Main body fitting side 12. Upper part of the main body fitting 13 Main body fitting tip 14 Rear end of main body fitting 2. Cover fitting section 21 Cover fitting side 22 Upper part of the lid fitting 23 Cover fitting tip M Container body M1 bottom M2 Main body side M3 Main body flange section M31 Main body flange corner M32 Main flange straight section M33 Main body flange stepped section M33a Main flange first step section M33b Main flange second step section N Lid N1 Top section N2 Side of the lid N3 Cover flange section N31 Cover flange corner N32 Cover flange straight section N33 Cover flange step section N33a Cover flange first step portion VL1, VL2 Main unit virtual diagonal VL3, LV4 Cover Virtual Diagonal

Claims

1. A fitting structure for a packaging container comprising a container body and a lid, The body fitting portion of the container body and the lid fitting portion of the lid are fitted together in a direction that connects the inside and outside of the packaging container. A fitting structure for packaging containers.

2. The main body fitting portion and the lid fitting portion are located along a radial direction from a predetermined point on the packaging container. The fitting structure for a packaging container according to claim 1.

3. The main body fitting portion and the lid fitting portion are fitted together, with one having a fitting under portion and the other having a fitting protrusion. The fitting under portion and the fitting protrusion extend radially from a predetermined point on the packaging container. The fitting structure for a packaging container according to claim 1 or 2.

4. The container body has a main body flange portion, The cover has a cover flange portion that faces the main body flange portion, The main body fitting portion is formed in a convex shape toward the lid flange portion, The lid fitting portion is formed in a concave shape capable of accommodating the main body fitting portion. The fitting structure for a packaging container according to claim 1.

5. The container body has a main body flange portion, The cover has a cover flange portion that faces the main body flange portion, The lid fitting portion is formed in a convex shape toward the main body flange portion, The main body fitting portion is formed in a concave shape so as to accommodate the lid fitting portion. The fitting structure for a packaging container according to claim 1.

6. The main body fitting portion is located at the corner of the main body flange portion in a plan view, The lid fitting portion is located at the corner of the lid flange portion in a plan view. The fitting structure for a packaging container according to claim 4 or 5.

7. The container body is made of a resin material containing starch. The fitting structure for a packaging container according to claim 1 or 2.

8. A packaging container having the fitting structure described in claim 1 or 2.

Images