Compound container

Abstract

A composite container 1A comprises a storage part 2 having a bottom surface, a peripheral surface, and an opening. The composite container 1A includes: a resin skeleton 11 forming a skeleton of the storage part 2; and a cylindrical part 12 including a sheet material forming the peripheral surface of the storage part 2 and joined, in a bent state, to the resin skeleton 11. In the cylindrical part 12, a loop stiffness measured when the sheet material is used as a loop-shaped sample piece having a peripheral length of 100 mm and the sample piece is pushed in by a push-in length of 10 mm is 20-900 mN / 15 mm width.

Description

Composite container

[0001] The present invention relates to a composite container having a bottom surface, a circumferential surface, and an opening for storage.

[0002] Conventionally, composite containers are known that have a housing section formed by integrally joining a blank and a resin skeleton by punching out a blank from a flat sheet material made of laminated resin films, inserting the blank into a mold and holding it, and then molding a resin skeleton by injection molding (see, for example, Patent Document 1).

[0003] In the composite container disclosed in Patent Document 1, the portion of the blank that forms the circumferential surface of the housing is inserted into the mold in a state that is curved in a substantially annular shape or bent in a substantially square annular shape, and thereafter is integrally joined with the resin skeleton by injection molding, thereby maintaining the state that is curved in a substantially annular shape or bent in a substantially square annular shape.

[0004] Japanese Patent Publication No. 2009-241951

[0005] In composite containers such as those described in Patent Document 1, if the rigidity strength, which indicates the degree to which the blank can push back when deformed from a flat plate shape to a roughly annular or roughly square annular shape, is too high, the resin skeleton may deform due to the force with which the blank tries to return to a flat plate shape. When such deformation occurs, it becomes impossible to ensure a tight seal with the lid when a lid is attached to the container. On the other hand, if the rigidity strength of the blank is too low, it becomes impossible to ensure sufficient rigidity of the circumferential portion of the container. When contents are filled into the container, the circumferential portion of the container may bulge excessively, or it may break when subjected to impact such as dropping from a certain height, thus failing to adequately ensure the functionality and durability of the container.

[0006] This invention has been made in view of the above-mentioned problems, and aims to provide a composite container that can sufficiently ensure airtightness with the lid, while also ensuring sufficient functionality and durability as a container.

[0007] The characteristic configuration of the composite container according to the present invention for solving the above problems is a composite container having a storage section having a bottom surface, a circumferential surface and an opening, comprising: a resin skeleton that forms the framework of the storage section; and a cylindrical section that includes a sheet material forming the circumferential surface of the storage section and is joined to the resin skeleton in a bent state, wherein the cylindrical section has a loop stiffness of 20 to 900 mN / 15 mm width when the sheet material is made into a loop-shaped sample piece with a circumference of 100 mm and the sample piece is pressed in for a pressing length of 10 mm.

[0008] In this composite container configuration, the cylindrical portion, including the sheet material forming the circumferential surface of the containment section, is joined to the resin skeleton in a bent state and inherently possesses a force that tries to return it to a flat state. In this composite container configuration, the loop stiffness of the cylindrical portion, as measured under the above test conditions, is set to 20 to 900 mN / 15 mm width. By setting the upper limit of the loop stiffness to 900 mN / 15 mm width, the rigidity of the cylindrical portion is not too high, and deformation of the resin skeleton due to the force that tries to return the cylindrical portion to a flat state can be suppressed. As a result, sufficient airtightness with the lid can be ensured. On the other hand, by setting the lower limit of the loop stiffness to 20 mN / 15 mm width, the rigidity of the cylindrical portion is not too low, and a certain level of rigidity can be ensured for the circumferential surface portion of the containment section. As a result, when the contents are filled into the container, it is possible to prevent the periphery of the container from bulging excessively, and to prevent damage to the periphery of the container even when subjected to impact from drops from a certain height, thereby ensuring sufficient functionality and durability as a container. Furthermore, in insert molding, it is possible to suppress the unintended bending or creasing of the sheet material when inserting it into the mold. This prevents leakage of contents when the container is filled and also results in a superior appearance.

[0009] In the composite container according to the present invention, the sheet material preferably comprises a base material layer and an inner sealant layer provided adjacent to the base material layer and inside the housing portion.

[0010] With this composite container configuration, the sheet material base layer provides rigidity, strength, toughness, etc., thus suppressing deformation of the cylindrical part, making it less likely to break even if deformed, and ensuring the rigidity required for the housing. Furthermore, the inner sealant layer provided adjacent to the base layer on the inside of the housing provides thermal sealing properties, so the cylindrical part can be reliably joined to the resin skeleton in a tight seal during insert molding.

[0011] In the composite container according to the present invention, it is preferable that the sheet material further comprises a surface resin layer provided adjacent to the base material layer and on the outside of the housing portion.

[0012] In this composite container configuration, the sheet material further includes a surface resin layer provided adjacent to the base material layer on the outside of the storage section. This not only suppresses deformation of the cylindrical section due to external forces, but also prevents damage to the cylindrical section from reaching deep inside, for example, if it comes into contact with or rubs against other transported items during transportation, as the surface resin layer protects the base material layer.

[0013] In the composite container according to the present invention, the base material layer preferably includes a resin layer and / or a paper-like layer.

[0014] In this composite container configuration, the base layer that imparts rigidity, strength, toughness, etc., to the cylindrical portion includes a resin layer and / or a paper-like layer. When the base layer is mainly composed of a resin layer, the loop stiffness value becomes relatively small, and when the base layer is mainly composed of a paper-like layer, the loop stiffness value becomes relatively large. Therefore, by composing the base layer mainly of a resin layer or a paper-like layer, or by adjusting the ratio of the resin layer to the paper-like layer in the base layer, the loop stiffness value can be easily adjusted, and the rigidity, etc., required for the cylindrical portion can be easily adjusted according to the contents, transportation conditions, usage conditions, etc.

[0015] In the composite container according to the present invention, the resin skeleton preferably comprises an upper annular skeleton portion that forms the contour of the opening and a columnar skeleton portion connected to the upper annular skeleton portion, wherein the columnar skeleton portion is preferably fused and integrated with the inner sealant layer.

[0016] With this composite container configuration, the rigidity required around the opening of the housing can be secured by the upper annular skeletal structure, and the columnar skeletal structure connected to the upper annular skeletal structure is fused and integrated with the inner sealant layer, thereby reducing the amount of resin used to constitute the resin skeleton, while the required rigidity on the circumferential surface of the housing can be secured by supporting key points of the cylindrical section with the columnar skeletal structure.

[0017] In the composite container according to the present invention, it is preferable that in the portion where one end and the other end of the sheet material overlap, the inner sealant layer on one end of the sheet material and the surface resin layer on the other end are fused together and integrated.

[0018] With this composite container configuration, the inner sealant layer on one end of the sheet material has excellent thermal sealing properties, allowing for reliable fusion and integration of the inner sealant layer on one end of the sheet material with the surface resin layer on the other end, thus ensuring a secure joint at the overlapping portion of the sheet material. Therefore, for example, by joining the sheet material at the resin skeleton (columnar skeleton portion), leakage or seepage of the contents can be reliably prevented. Furthermore, overlapping the sheet material improves its physical strength. In addition, if the sheet material has barrier properties, overlapping the sheet material with barrier properties eliminates gaps in the barrier performance, resulting in high barrier properties.

[0019] In the composite container according to the present invention, the resin skeleton further has a lower skeleton connected to the lower side of the upper annular skeleton via the columnar skeleton, and it is preferable that the surface area of ​​the portion of the cylindrical part that is in contact with the internal space of the housing (excluding the inside of the housing) is 50% or more of the surface area of ​​the housing above the upper end of the lower skeleton (excluding the inside of the housing).

[0020] With this composite container configuration, the surface area of ​​the cylindrical portion that is in contact with the internal space of the housing (excluding the inside of the housing) is 50% or more of the surface area of ​​the housing above the upper end of the lower skeletal portion (excluding the inside of the housing), thus the amount of resin used can be reliably reduced.

[0021] In the composite container according to the present invention, the base material layer does not include a paper-like layer but includes a resin layer, and the loop stiffness is preferably 100 to 130 mN / 15 mm width.

[0022] In a resin tubular container where the base layer does not include a paper layer but includes a resin layer, meaning the sheet material constituting the tubular part is mainly composed of a resin layer, if the loop stiffness measured under the above test conditions is less than the lower limit of 100 mN / 15 mm width specified in this invention, the rigidity of the tubular part is too low, making it difficult to wrap the tubular part around the resin skeleton, and even if it is wrapped, the wrapped state may not be maintained. If the loop stiffness measured under the above test conditions exceeds the upper limit of 130 mN / 15 mm width specified in this invention, the rigidity of the tubular part is too high, and the resin skeleton may deform to such an extent that sufficient airtightness with the lid cannot be ensured. With the composite container of this configuration, the loop stiffness measured under the above test conditions when the tubular part is made of resin is set to an appropriate numerical range, making it easier to wrap the tubular part around the resin skeleton and maintaining the wrapped state, thereby contributing to improved appearance, and also suppressing deformation of the resin skeleton to ensure sufficient airtightness with the lid.

[0023] In the composite container according to the present invention, the base material layer does not include a paper-like layer but includes a resin layer, and it is preferable that the coefficient of dynamic friction of the sheet material with respect to the resin skeleton, as measured in accordance with JIS K7125, is 0.20 to 0.50.

[0024] In a resin tubular part where the base layer does not include a paper layer but includes a resin layer, that is, where the sheet material constituting the tubular part is mainly composed of a resin layer, if the dynamic friction coefficient of the sheet material with respect to the resin skeleton, measured in accordance with JIS K7125, is less than the lower limit of 0.20 specified in this invention, the sheet material becomes excessively slippery against the resin skeleton, which may cause the sheet material to shift position relative to the resin skeleton, or worsen handling, such as making it difficult to bundle the sheet material and transport it to the machine during insert molding, potentially leading to a decrease in production efficiency. If the dynamic friction coefficient of the sheet material with respect to the resin skeleton, measured in accordance with JIS K7125, exceeds the upper limit of 0.50 specified in this invention, the sheet material becomes excessively less slippery against the resin skeleton, which may worsen handling, such as making it difficult to remove the sheet material from the magazine where the sheet material is accumulated during insert molding, potentially leading to a decrease in production efficiency. With this composite container configuration, the coefficient of dynamic friction of the sheet material against the resin skeleton, measured in accordance with JIS K7125, is set to an appropriate numerical range. This makes it easier to position the sheet material relative to the resin skeleton, improves handling, and increases production efficiency.

[0025] In the composite container according to the present invention, it is preferable that the container is configured to contain a specific resin, and when the content of the specific resin in the entire container is a1 (parts by mass) and the content of materials other than the specific resin in the entire container is a2 (parts by mass), the monomaterial ratio M, expressed by the following formula (1): M = a1 / (a1+a2) × 100 ... (1), is configured to be 80% or more.

[0026] According to this composite container configuration, the monomaterial ratio M represented by formula (1) above is 80% or more, so it can be considered to contain substantially no materials other than the specified resin (mainly resin), making recycling easier and potentially contributing to decarbonization and environmental protection.

[0027] In the composite container according to the present invention, the specific resin is preferably polypropylene (PP).

[0028] With this composite container configuration, by selecting polypropylene (PP) as the specific resin, it is possible to create a container that is lightweight yet possesses excellent properties such as heat resistance, chemical resistance, and durability, making it suitable for use as a container for food, pharmaceuticals, industrial products, and the like.

[0029] In the composite container according to the present invention, it is preferable that the container is composed of paper, and that the paper content ratio, which is the ratio of the mass of paper to the total mass of the container, is 50% or more.

[0030] With this composite container configuration, the paper content is 50% or more, which allows for a significant reduction in the amount of resin used while ensuring the container's functionality.

[0031] Figure 1 is an explanatory diagram of a composite container according to the first embodiment of the present invention. Figure 2 is an exploded perspective view of the housing section. Figure 3 is an explanatory diagram of the blanks constituting the cylindrical section and the bottom plate section. Figure 4 is a schematic diagram for explaining the method of measuring loop stiffness. Figure 5 is an explanatory diagram of the bonding state of the cylindrical section to the resin skeleton. Figure 6 is an explanatory diagram regarding the ratio of the surface area of ​​a specific part of the housing section. Figure 7 is an explanatory diagram of a composite container according to the second embodiment of the present invention. Figure 8 is an exploded perspective view of the housing section. Figure 9 is an explanatory diagram of the blanks constituting the cylindrical section and the bottom plate section. Figure 10 is an explanatory diagram of the bonding state of the cylindrical section to the resin skeleton. Figure 11 is an explanatory diagram regarding the ratio of the surface area of ​​a specific part of the housing section.

[0032] The present invention will now be described with reference to the drawings. However, the present invention is not intended to be limited to the embodiments and configurations described below or shown in the drawings. In Figures 3, 5, 9 and 10, it is shown that the sheet material S is composed of multiple layers, and in Figures 5, 6, 8, 10 and 11, cross-sections of various components such as the cylindrical portion 12, the bottom plate portion 13, and the resin skeleton 11 are shown. However, the thickness relationships of each layer and the thickness relationships of the cross-sections of the various components have been exaggerated or simplified as appropriate for ease of understanding in the drawings, and do not strictly reflect the actual thickness of each layer in the sheet material S or the relative thicknesses (scale) of the cross-sections of the various components.

[0033] [First Embodiment] <Overall Configuration> Figure 1 is an explanatory diagram of a composite container 1A according to the first embodiment of the present invention. Figure 1(a) is a perspective view showing the state in which the lid 3 is attached to the storage section 2. Figure 1(b) is a perspective view showing the state in which the lid 3 has been removed from the storage section 2. As shown in Figures 1(a) and (b), the composite container 1A comprises a storage section 2 that functions as a container body for storing contents not shown, and a lid 3 that is detachable from the storage section 2. In this example, as a sealing structure for sealing the storage section 2 and the lid 3 together, an external fitting type is adopted in which the lid 3 is fitted to the upper end (flange section 32, described later) of the storage section 2 in such a manner that the peripheral edge of the lid 3 surrounds the upper end. However, it is not limited to this, and an internal fitting type in which the lid 3 is fitted to the upper end of the storage section 2 on the inside, or a heat sealing type in which an easy-peel layer is interposed between the storage section 2 and the lid 3 and heat-sealed may also be adopted.

[0034] <Storage Section> As shown in Figure 1(b), the storage section 2 has a rounded rectangular bottom surface 2a, a circumferential surface 2b formed in an upright state from the outer edge of the bottom surface 2a, and an opening 2c that is open upward at the upper end of the circumferential surface 2b. The internal space partitioned by the bottom surface 2a and the circumferential surface 2b becomes the storage space 2d for storing contents. The circumferential contour of the circumferential surface 2b gradually increases in size as it progresses upward from the bottom surface 2a side, forming an inverted truncated square pyramid shape with a hollow section when viewed externally.

[0035] Figure 2 is an exploded perspective view of the housing section 2. As shown in Figure 2, the housing section 2 comprises a resin frame 11, a cylindrical section 12, and a bottom plate section 13.

[0036] <Resin skeleton> The resin skeleton 11 has an upper annular skeleton portion 21 and a lower skeleton portion 22 that are spaced apart in the vertical direction and share the same vertical central axis (axis L), and a columnar skeleton portion 23 that is interposed between the upper annular skeleton portion 21 and the lower skeleton portion 22. The type of resin constituting the resin skeleton 11 is not particularly limited, but general-purpose resins such as polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET) can be used.

[0037] The upper annular skeleton portion 21 has an upper annular wall portion 31 formed in a rounded rectangular ring shape (rounded rectangular annular shape) to form the contour of the opening 2c of the accommodating portion 2, and a rounded rectangular ring-shaped flange portion 32 is integrally provided so as to project outward in the horizontal direction from the outer peripheral edge portion on the upper end side of the upper annular wall portion 31. With the upper annular skeleton portion 21 having such a configuration, it is possible to ensure the rigidity required around the opening 2c of the accommodating portion 2. In particular, the flange portion 32 is a member required for fitting with the lid 3 in the sealing structure with the lid 3, and also functions as a reinforcing member for reinforcing the upper annular wall portion 31. In this embodiment, an example in which the upper annular skeleton portion 21 is formed in a rounded rectangular ring shape (rounded rectangular annular shape) is shown, but this is merely an example and is not particularly limited, and any shape such as a triangular annular shape with rounded corners or a polygonal annular shape with five or more sides can be selected.

[0038] The lower skeleton portion 22 has a lower annular wall portion 33 formed in a rounded rectangular ring shape (rounded rectangular annular shape) to form the contour of the bottom portion of the accommodating portion 2, and a rounded rectangular ring-shaped flange portion 34 is integrally provided so as to project inward in the horizontal direction from the inner peripheral edge portion on the lower end side of the lower annular wall portion 33. Further, a reinforcing portion 35 is integrally provided in a form like an X-shaped crossbar (diagonal crossbar) so as to connect two non-adjacent corners (diagonal portions) of the flange portion 34. In this embodiment, an example in which the reinforcing portion 35 is formed in an X shape is shown, but this is merely an example and is not particularly limited, and as other examples, a cross shape or a combined shape combining an X shape and a cross shape may also be used. Also, there may be an example in which a resin bottom plate is provided so as to block the entire inner peripheral side region of the lower annular wall portion 33.

[0039] The columnar skeleton portion 23 is connected such that one end side is connected to the upper annular wall portion 31 and the other end side is connected to the lower annular wall portion 33 so as to connect the respective corners of the upper annular skeleton portion 21 and the lower skeleton portion 22.

[0040] <Cylindrical Portion>FIG. 3 is an explanatory view of blanks 101 and 102 that constitute the cylindrical portion 12 and the bottom plate portion 13. FIG. 3(a) is a plan view of the blanks 101 and 102. The cylindrical portion 12 is formed from a first blank 101 obtained by subjecting a flat sheet material S having a laminated structure (see FIGS. 3(b) and 3(c)) described later to a punching process to form a predetermined shape capable of forming the peripheral surface 2b of the accommodating portion 2. The four columnar skeleton portions 23 are joined to the upper annular wall portion 31, the lower annular wall portion 33, and the four columnar skeleton portions 23 in the resin skeleton 11 in a state where the portions corresponding to the four columnar skeleton portions 23 are bent from the outer peripheral side.

[0041] As shown in FIG. 3(a), the first blank 101 that constitutes the cylindrical portion 12 has four panel portions 101a to 101d capable of closing each of the four side openings formed by being surrounded by the upper annular wall portion 31, the lower annular wall portion 33, and the adjacent columnar skeleton portions 23 in the resin skeleton 11, and has a fusion margin portion 101e capable of being fused to the upper annular wall portion 31, the lower annular wall portion 33, and the columnar skeleton portions 23.

[0042] FIG. 3(b) is a cross-sectional end view taken along the A - A arrow in FIG. 3(a), and shows a case where the base material layer 111 is mainly composed of a resin layer or a paper layer. As shown in FIG. 3(b), the sheet material S that constitutes the first blank 101 includes a base material layer 111, an inner sealant layer 112 provided inside the accommodating portion 2 adjacent to the base material layer 111, and a surface resin layer 113 provided outside the accommodating portion 2 adjacent to the base material layer 111.

[0043] <Base layer, resin layer> The base layer 111 is a layer provided to impart the required rigidity, strength, toughness, etc., to the cylindrical portion 12. When the base layer 111 is mainly composed of a resin layer (resin film layer), the type of resin constituting the resin layer is not particularly limited, but examples include polyethylene terephthalate (PET), nylon film (NY), polypropylene (PP), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), polymethylpentene (PMP), polyethylene (PE), etc. The resin layer is preferably a stretched resin film. Alternatively, the resin layer may be a composite resin film obtained by laminating two or more of these resin films. The thickness of the base layer 111 is preferably 10 to 300 μm, and more preferably 20 to 200 μm.

[0044] The base layer 111 preferably has a structure in which a barrier layer is laminated on a resin layer that serves as the base material. The barrier layer is a functional layer that blocks oxygen, water vapor, etc., and improves the preservation of the contents. The barrier layer can be composed of, for example, a vapor-deposited film of an inorganic compound such as silica or alumina, a vapor-deposited film of a metal such as aluminum, a metal foil such as aluminum, a plate-like mineral, and / or a barrier resin. When the barrier layer is formed from a vapor-deposited metal film or metal foil, light-shielding properties can also be provided to the cylindrical portion 12. As the barrier resin, ethylene-vinyl alcohol copolymer (EVOH) or polyvinylidene chloride (PVDC) can be used, and a binder resin is appropriately blended into the barrier resin. The barrier layer may be pre-laminated on the resin layer that serves as the base material to form a barrier film, or it may be provided as a single layer film. The barrier layer may also be a film of a barrier resin such as EVOH or PVDC. When the base layer 111 is mainly composed of a resin layer, the loop stiffness value, which will be described later, tends to be relatively small.

[0045] <Base Layer, Paper Layer> When the base layer 111 is mainly composed of a paper layer containing paper and / or pulp, the paper layer may be any paper containing 50% or more pulp fibers (cellulose fibers), or it may be a mixed paper containing resin fibers in addition to pulp fibers. The type of paper that makes up the paper layer is not particularly limited. Examples of paper types include single-sided gloss kraft paper, double-sided gloss kraft paper, water-resistant paper, oil-resistant paper, and cup base paper. Of these, cup base paper is preferred in terms of strength, bending resistance, and printability. The basis weight of the paper used for the paper layer is 80 to 1400 g / m². ２ The amount is 100-600 g / m². ２ Preferably, it is 150 to 500 g / m ２ It is more preferable that this be the case. In this example, the basis weight of the paper is 400 g / m². ２ To that extent, when the base layer 111 is mainly composed of a paper-like layer, the loop stiffness value, which will be described later, tends to be relatively large.

[0046] <Inner sealant layer> The inner sealant layer 112 is a layer provided to give heat sealing properties to ensure a tight bond with the resin skeleton 11 during insert molding. The material of the inner sealant layer 112 is not particularly limited, but it is preferably a thermoplastic resin such as polypropylene, polyethylene, or polyethylene terephthalate. The thermoplastic resin used for the inner sealant layer 112 should be adhesive to the thermoplastic resin constituting the resin skeleton 11, but it is preferably the same material as the thermoplastic resin used for the resin skeleton 11. By making the thermoplastic resin used for the inner sealant layer 112 the same as the thermoplastic resin layer used for the resin skeleton 11, the seal strength between the cylindrical portion 12 and the resin skeleton 11 can be improved. The thickness of the inner sealant layer 112 is preferably 20 to 150 μm, and more preferably 40 to 100 μm.

[0047] <Surface Resin Layer> The surface resin layer 113 is a layer that protects the base layer 111 from external forces and the adhesion of dirt. The type of resin that constitutes the surface resin layer 113 and the method of forming it are not particularly limited, but the surface resin layer 113 can be formed by extrusion coating of olefin-based thermoplastic resin such as polyethylene or polypropylene, or by coating with a coating agent such as a water-resistant agent or an oil-resistant agent. The thickness of the surface resin layer 113 is preferably 10 to 150 μm, and more preferably 15 to 100 μm. By providing such a surface resin layer 113, deformation of the cylindrical part 12 due to external forces can be suppressed even more effectively, and for example, even if it comes into contact with or rubs against other transported goods during transportation, the surface resin layer 113 protects the base layer 111, preventing damage to the cylindrical part 12 from reaching deep inside. Furthermore, by making the surface resin layer 113 a resin that can be heat-welded to the resin skeleton 11, the physical strength can be increased, and by protecting the edges of the paper when paper is used, it is possible to prevent water or contents from seeping into the paper.

[0048] Figure 3(c) is a cross-sectional view taken along the line A-A in Figure 3(a), showing the case where the base layer 111 is composed of a resin layer 111a and a paper-like layer 111b. As shown in Figure 3(c), the base layer 111 may be composed of a resin layer 111a and a paper-like layer 111b in an appropriate combination. By adjusting the ratio of the resin layer 111a to the paper-like layer 111b in the base layer 111, the value of the loop stiffness, which will be described later, can be easily adjusted, and the rigidity required of the cylindrical portion 12 can be easily adjusted according to the contents, transportation conditions, usage conditions, etc.

[0049] The sheet material S is not limited to a laminated structure consisting of a base layer 111 (resin layer 111a, paper layer 111b), an inner sealant layer 112, and a surface resin layer 113, as shown in Figures 3(b) and (c). In addition to the layers listed above, an ink layer applied by printing for various markings and an overcoat varnish layer for providing abrasion resistance, etc., can be appropriately provided. The lamination order of the ink layer and the overcoat varnish layer is not particularly limited.

[0050] <Bottom Plate Section> The bottom plate section 13 shown in Figure 2 is made up of a rounded rectangular (rounded rectangular) second blank 102 as shown in Figure 3(a), which is formed by punching out a flat sheet material S having the laminated structure described above to create a predetermined shape that can form the bottom surface of the storage section 2, and is joined to the lower skeletal section 22 of the resin skeleton 11 from the bottom side in a flat state.

[0051] As shown in Figure 3(a), the second blank 102 has faceplate portions 102a to 102d that can close each of the four bottom openings formed by being surrounded by the flange portion 34 and the reinforcing portion 35 of the resin skeleton 11, and also has a fusion allowance portion 102e that can be fused to the lower skeleton portion 22.

[0052] <Method for Measuring Loop Stiffness> Figure 4 is a schematic diagram illustrating the method for measuring loop stiffness. In this specification, loop stiffness (rigidity) is defined as the repulsive force measured when a sheet material S is used as a loop-shaped sample piece 200 with a circumference of 100 mm, the sample piece 200 is sandwiched between a pressing plate 201 and a fixing plate 202 that are facing each other, and the sample piece 200 is pressed towards the fixing plate 202 by the pressing plate 201 for a pressing length of 10 mm, as shown in Figure 4.

[0053] In the composite container 1A of the first embodiment, the loop stiffness of the cylindrical portion 12, as measured by the loop stiffness measurement method described above, is set to 20 to 900 mN / 15 mm width. By setting the upper limit of the loop stiffness to 900 mN / 15 mm width, the rigidity of the cylindrical portion 12 is not too high, and deformation of the resin skeleton 11 due to the force that tries to return the cylindrical portion 12 to a flat shape can be suppressed. As a result, sufficient airtightness with the lid 3 can be ensured. On the other hand, by setting the lower limit of the loop stiffness to 20 mN / 15 mm width, the rigidity of the cylindrical portion 12 is not too low, and the rigidity of the circumferential portion of the storage portion 2 can be ensured to a certain level or higher. As a result, when contents are filled into the storage portion 2, it is possible to prevent the circumferential portion of the storage portion 2 from expanding excessively, and even if an impact such as dropping from a certain height is applied, it is possible to prevent damage to the circumferential portion of the storage portion 2, thereby ensuring sufficient functionality and durability as a container.

[0054] In the composite container 1A of the first embodiment, the base layer 111 does not include a paper-like layer 111b as shown in Figure 3(c), but includes a resin layer 111a (a single resin layer or a laminate of multiple resin layers), and the sheet material S, which is a laminate of a surface resin layer 113, a base layer 111 (resin layer 111a), and an inner sealant layer 112, is mainly made of resin, and the cylindrical portion 12 is made of resin, it is preferable that the loop stiffness measured by the above loop stiffness measurement method is 100 to 130 mN / 15 mm width (the same applies to the composite container 1B of the second embodiment described later). By setting the numerical range to this extent, it is possible to easily wrap the cylindrical portion 12 around the resin skeleton 11 and maintain the wrapped state, thereby contributing to an improved appearance, and deformation of the resin skeleton 11 can be suppressed, ensuring sufficient airtightness with the lid 3. If the cylindrical portion 12 is made of resin, and the loop stiffness is less than the lower limit of 100 mN / 15 mm width specified in this invention, the rigidity of the cylindrical portion 12 will be too low, making it difficult to wrap the cylindrical portion 12 around the resin skeleton 11, and even if it is wrapped, the wrapped state may not be maintained. If the cylindrical portion 12 is made of resin, and the loop stiffness exceeds the upper limit of 130 mN / 15 mm width specified in this invention, the rigidity of the cylindrical portion 12 will be too high, and the resin skeleton 11 may deform to such an extent that sufficient airtightness with the lid 3 cannot be ensured.

[0055] Here, when the cylindrical portion 12 is made of resin, the phrase "the sheet material S is mainly composed of resin" means that, when the total mass of the sheet material S constituting the cylindrical portion 12 is considered to be 100% by mass, the resin content exceeds 50% by mass, preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and most preferably 95% by mass or more. There is no particular upper limit, and it may be 100% by mass. When the resin content is less than 100% by mass, the components other than resin contained in the sheet material S constituting the cylindrical portion 12 are not particularly limited (excluding paper and / or pulp), and may include conventionally known components.

[0056] Furthermore, when the cylindrical portion 12 is made of resin, the surface resin layer 113, the base material layer 111 (resin layer 111a), and the inner sealant layer 112 that constitute the sheet material S are each mainly composed of resin. In this case, "main component" refers to the resin component excluding additives such as plasticizers, fillers, and stabilizers. The content of the main component is greater than 50% by mass, preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and most preferably 95% by mass or more, when the total components constituting the sheet material S are considered to be 100% by mass. There is no particular upper limit, and it may be 100% by mass.

[0057] In the composite container 1A of the first embodiment, as described above, when the cylindrical portion 12 is made of resin, it is preferable that the dynamic friction coefficient of the sheet material S with respect to the resin skeleton 11, measured in accordance with JIS K7125, be 0.20 to 0.50 (the same applies to the composite container 1B of the second embodiment described later). By setting the value within this range, the positioning of the sheet material S with respect to the resin skeleton 11 becomes easier, handling improves, and production efficiency can be increased. When the cylindrical portion 12 is made of resin, if the dynamic friction coefficient is less than the lower limit of 0.20 specified in the present invention, the sheet material S becomes excessively slippery with respect to the resin skeleton 11, which may cause the sheet material S to shift position relative to the resin skeleton 11, or make it difficult to bundle the sheet material S and transport it to the machine during insert molding, for example, leading to poor handling and a decrease in production efficiency. When the cylindrical portion 12 is made of resin, if the coefficient of dynamic friction exceeds the upper limit of 0.50 specified in the present invention, the sheet material S will become excessively difficult to slide against the resin skeleton 11. This can lead to poor handling, such as difficulty in removing the sheet material S from the magazine where the sheet material S is accumulated during insert molding, and may result in a decrease in production efficiency.

[0058] When a composite container 1A is configured to contain a specific resin, the content of that specific resin in the resin product is defined as the "monomaterial content". For example, when a composite container 1A is composed of polypropylene (PP), polyethylene (PE), and nylon (NY), and the specific resin is polypropylene (PP), the monomaterial content M of polypropylene (PP) in the composite container 1A is expressed by the following formula (1), where a1 (parts by mass) is the content of polypropylene (PP) in the entire composite container 1A, and a2 (parts by mass) is the content of materials other than polypropylene (PP) (mainly resins) in the entire composite container 1A (in this example, the total content of polyethylene (PE) and nylon (NY)). M = a1 / (a1+a2) × 100 ... (1) In addition, in the above composite container 1A, it is also possible to define the specific resin as a higher-level concept such as polyolefin resin, in which case polypropylene (PP) and polyethylene (PE) would be the specific resins, and nylon (NY) would be the resins other than the specific resin.

[0059] When the composite container 1A is configured such that the monomaterial ratio M represented by the above formula (1) is 80% or more, it can be considered to contain substantially no resins other than the specified resin, making recycling easier and contributing to decarbonization and environmental protection (the same applies to the composite container 1B of the second embodiment described later).

[0060] Furthermore, the specific resin is preferably polypropylene (PP). By selecting polypropylene (PP) as the specific resin, it is possible to create a container that is lightweight yet possesses excellent properties such as heat resistance, chemical resistance, and durability, making it suitable for use as a container for food, pharmaceuticals, industrial products, and the like.

[0061] Furthermore, if the composite container 1A is constructed containing paper, it is preferable that the paper content ratio, which is the ratio of the weight of paper to the total weight of the composite container 1A, be 50% or more. This makes it possible to significantly reduce the amount of resin used while ensuring the functionality of the container (the same applies to the composite container 1B of the second embodiment described later).

[0062] Figure 5 is an explanatory diagram of the bonding state of the cylindrical portion 12 to the resin skeleton 11. Figure 5(a) schematically shows the end face when the main part of the housing portion 2 is cut along the horizontal plane. Figure 5(b) is an enlarged view of portion B in Figure 5(a). Figure 5(c) is an enlarged view of portion C in Figure 5(a).

[0063] As shown in Figure 5(a), the cylindrical portion 12 is formed by a roughly strip-shaped first blank 101, which is relatively longer in the left-right direction compared to the up-down direction in Figure 3(a). Between one end and the other end of the first blank 101 in the longitudinal direction, portions corresponding to three of the four columnar skeletal portions 23 are bent into a shape resembling a quadrant arc. The portions on one end and the other end of the first blank 101 are bent into a curved shape that follows the remaining columnar skeletal portion 23. The four columnar skeletal portions 23 and the upper annular wall portion 31 and lower annular wall portion 33 adjacent to each columnar skeletal portion 23 in the longitudinal direction (up-down direction) are integrally joined to the four columnar skeletal portions 23 and the upper annular wall portion 31 and lower annular wall portion 33 adjacent to each columnar skeletal portion 23 in the longitudinal direction (up-down direction).

[0064] As shown in Figures 5(b) and (c), the cylindrical portion 12 and the columnar skeletal portion 23 are fused together and integrated via the inner sealant layer 112 of the sheet material S. This reduces the amount of resin used to constitute the resin skeleton 11, while ensuring the required rigidity on the circumferential surface of the housing portion 2 by supporting key points of the cylindrical portion 12 with the columnar skeletal portion 23.

[0065] As shown in Figure 5(b), in the cylindrical portion 12, the inner sealant layer 112 on one end of the sheet material S and the surface resin layer 113 on the other end are fused and integrated at the overlapping portion of the sheet material S. With this joining structure, since the inner sealant layer 112 on one end of the sheet material S has excellent heat sealing properties, the inner sealant layer 112 on one end of the sheet material S and the surface resin layer 113 on the other end can be reliably fused and integrated, and the overlapping portion of the sheet material S can be reliably joined. Therefore, it is possible to reliably prevent the contents from leaking or seeping from the overlapping portion of the sheet material S. In this way, by joining the one end and the other end of the sheet material S at the columnar skeletal portion 23, it is possible to reliably prevent the contents from leaking or seeping. In addition, the physical strength can be improved by overlapping the one end and the other end of the sheet material S. Furthermore, if the sheet material S has barrier properties, overlapping one end and the other end of the sheet material S with barrier properties eliminates gaps in the barrier performance, thereby providing high barrier properties.

[0066] Figure 6 is an explanatory diagram relating to the ratio of the surface area of ​​a specific part of the housing section 2. Figure 6 schematically shows an end view when the main part of the housing section 2 is cut along a vertical plane. The surface area (A), surface area (B), and surface area (C) used in the following explanation are defined as follows. Surface area (A) is the surface area of ​​the part of the cylindrical section 12 that is in contact with the housing space 2d of the housing section 2 (excluding the inside of the housing section 2). That is, in Figure 6, the symbol "R" in the figure. Ａ The region indicated by "R" is the outer surface area of ​​the portion that closes the side opening, which is formed by being surrounded by the upper annular wall portion 31, the lower annular wall portion 33, and the adjacent columnar skeletal portion 23 of the resin skeleton 11 in the cylindrical portion 12. Surface area (B) is the region indicated by the symbol "R" in Figure 6. ＢThe area indicated by the dashed line marked with "" is the surface area of ​​the upper annular skeleton portion 21 facing the outside of the housing portion 2, that is, the sum of the outer surface area of ​​the flange portion 32 and the upper annular wall portion 31, which are integrally connected across the boundary position indicated by the arrow marked with the symbol "D" in the figure. Surface area (C) is the area indicated by the dashed line marked with "R" in the figure. Ｃ This is the area indicated by the dotted line marked with a quotation mark, and it refers to the surface area of ​​the outer wall surface of the upper annular wall portion 31.

[0067] In the first embodiment, the surface area (A) is set to be 50% or more of the surface area (A + B + C) obtained by adding the surface area (A), surface area (B), and surface area (C) of the housing portion 2 above the upper end of the lower skeletal portion 22, i.e., the upper end of the lower annular wall portion 33 (housing portion 2 within the range indicated by the arrow "E" in Figure 6), excluding the inside of the housing portion 2. By setting it in this way, the amount of resin used can be reliably reduced.

[0068] <Method for Manufacturing a Composite Container> Although a detailed explanation with illustrations is omitted, the composite container 1A of the first embodiment can be manufactured as follows by applying the insert molding method. First, a mold (not shown) corresponding to the resin skeleton 11 and a first blank 101 and a second blank 102 that have been cut into predetermined shapes in advance by punching the sheet material S are prepared. Then, the first blank 101 and the second blank 102 are placed in predetermined positions in the mold as inserts, and molten resin is filled into the mold.

[0069] In the composite container 1A of the first embodiment described above, the cylindrical portion 12, which includes the sheet material S forming the circumferential surface of the housing portion 2, is joined to the resin skeleton 11 in a bent state and inherently possesses a force that tries to return it to a flat state. The loop stiffness of the cylindrical portion 12, as measured under the above test conditions, is set to 20 to 900 mN / 15 mm width. By setting the upper limit of the loop stiffness to 900 mN / 15 mm width, the rigidity of the cylindrical portion 12 is not too high, and deformation of the resin skeleton 11 due to the force that tries to return the cylindrical portion 12 to a flat state can be suppressed. As a result, sufficient airtightness with the lid 3 can be ensured. On the other hand, by setting the lower limit of the loop stiffness to 20 mN / 15 mm width, the rigidity of the cylindrical portion 12 is not too low, and sufficient rigidity of the circumferential portion of the housing portion 2 can be ensured. As a result, when the contents are filled into the storage section 2, it is possible to prevent the circumferential surface of the storage section 2 from bulging excessively, and to prevent damage to the circumferential surface of the storage section 2 even when subjected to impacts such as dropping from a certain height, thereby ensuring sufficient functionality and durability as a container. Furthermore, in insert molding, it is possible to suppress the unintended bending or creasing of the sheet material S when inserting it into the mold. This prevents leakage of contents when the container is filled and also results in a superior appearance.

[0070] [Second Embodiment] <Overall Configuration> Figure 7 is an explanatory diagram of a composite container 1B according to the second embodiment of the present invention. Figure 7(a) is a perspective view showing the state in which the lid 3 is attached to the storage section 2. Figure 7(b) is a perspective view showing the state in which the lid 3 has been removed from the storage section 2. In the second embodiment, components that are the same as or similar to those in the first embodiment are denoted by the same reference numerals in the figure.

[0071] As shown in Figures 7(a) and (b), the composite container 1B comprises a storage section 2 that functions as a container body for contents not shown, and a lid 3 that is detachable from the storage section 2. In this example, an external screw type is used as the sealing structure for combining the storage section 2 and the lid 3, in which a female screw (not shown) on the lid 3 is screwed into a male screw 25 provided on the upper end of the storage section 2. However, it is not limited to this, and other types of sealing may be used, such as an internal screw type in which a male screw on the lid 3 is screwed into a female screw provided on the upper end of the storage section 2, an external fitting type in which the lid 3 is fitted to the upper end of the storage section 2 in such a way that the periphery of the lid 3 surrounds the upper end, an internal fitting type in which the lid 3 is fitted to the upper end of the storage section 2 from the inside, or a heat seal type in which an easy-peel layer is interposed between the storage section 2 and the lid 3 and heat-sealed.

[0072] <Storage Section> As shown in Figure 7(b), the storage section 2 has a circular bottom surface 2a, a circumferential surface 2b formed in an upright state from the outer edge of the bottom surface 2a, and an opening 2c that is open upward at the upper end of the circumferential surface 2b. The internal space partitioned by the bottom surface 2a and the circumferential surface 2b becomes the storage space 2d for storing contents. The circumferential contour of the circumferential surface 2b is constant from the bottom side upward and is formed in a cylindrical shape when viewed externally.

[0073] Figure 8 is an exploded perspective view of the housing section 2. As shown in Figure 8, the housing section 2 comprises a resin frame 11, a cylindrical section 12, and a bottom plate section 13.

[0074] <Resin skeleton> The resin skeleton 11 has an upper annular skeleton portion 21 and a lower skeleton portion 22 that are spaced apart in the vertical direction and share the same vertical central axis (axis L), and a columnar skeleton portion 23 that is interposed between the upper annular skeleton portion 21 and the lower skeleton portion 22. The same type of resin as in the first embodiment can be used to constitute the resin skeleton 11.

[0075] The upper annular skeletal portion 21 has a first upper annular wall portion 31a formed in an annular shape to form the outline of the opening 2c of the housing portion 2, and a second upper annular wall portion 31b integrally connected below the first upper annular wall portion 31a, with male screws 25 integrally provided on the outer circumferential surface of the first upper annular wall portion 31a. As shown in the cross-section view of the main part in Figure 8, the second upper annular wall portion 31b is constructed by integrally connecting a thick annular wall portion 41 that is thicker than the radial thickness of the first upper annular wall portion 31a and protrudes radially in a flange-like manner, and a thin annular wall portion 42 that is roughly the same thickness as the radial thickness of the first upper annular wall portion 31a but thinner than the radial thickness of the thick annular wall portion 41, making it relatively thin. With this configuration, the upper annular skeletal portion 21 allows the thick annular wall portion 41 to function as a reinforcing member that reinforces the upper annular wall portion 31, thereby ensuring the required rigidity around the opening 2c of the housing portion 2 while reducing the amount of resin used.

[0076] The lower skeletal portion 22 has a lower annular wall portion 33 that is formed in an annular shape and extends along the contour of the bottom of the housing portion 2 at a predetermined distance from the contour of the bottom of the housing portion 2. An annular flange portion 34 is integrally provided so as to protrude horizontally outward from the outer peripheral edge at the lower end of the lower annular wall portion 33, and a reinforcing portion 35 is integrally provided on the lower annular wall portion 33 so as to extend along the radial direction of the lower annular wall portion 33 and toward the connection point between the lower skeletal portion 22 and the columnar skeletal portion 23.

[0077] The columnar skeletal portion 23 is connected to the upper annular skeletal portion 21 and to the lower skeletal portion 22 at the connection point of the reinforcing portion 35 to the lower annular wall portion 33, with one end connected to the upper annular skeletal portion 21 and the other end connected to the lower skeletal portion 22.

[0078] <Cylindrical Section> Figure 9 is an explanatory diagram of the blanks 101 and 102 that constitute the cylindrical section 12 and the bottom plate section 13. Figure 9(a) is a plan view of the blanks 101 and 102. The cylindrical section 12 is composed of a first blank 101 which is made by punching out a flat sheet material S having a laminated structure similar to the laminated structure described above (see Figures 3(b) and (c)) to form a predetermined shape that can form the circumferential surface 2b of the housing section 2. The first blank 101 is joined to the second upper annular wall section 31b, the lower annular wall section 33 and the two columnar skeleton sections 23 of the resin skeleton 11 in a semi-cylindrical curved state.

[0079] <Bottom Plate Section> The bottom plate section 13 is composed of a second blank 102 which is made by punching out a flat sheet material S to form a predetermined shape that can form the bottom surface of the storage section 2, and is joined to the lower skeletal section 22 of the resin skeleton 11 from the bottom side in a flat state. The first blank 101 is connected to the second blank 102 via a connecting section 105.

[0080] The first blank 101 has faceplate portions 101a and 101b that can close the side opening formed by being surrounded by the second upper annular wall portion 31b, the lower annular wall portion 33 and the radially (circumferentially) adjacent columnar skeletal portions 23 of the resin skeleton 11, and also has a fusion allowance portion 101e that can be fused to the second upper annular wall portion 31b, the lower annular wall portion 33 and the columnar skeletal portions 23.

[0081] The second blank 102 has faceplate portions 102a and 102b that can close each of the two bottom openings formed by being surrounded by the lower annular wall portion 33 and the reinforcing portion 35 of the resin skeleton 11, and also has a fusion allowance portion 102e that can be fused to the lower annular wall portion 33, the flange portion 34 and the reinforcing portion 35.

[0082] Figure 9(b) is a cross-sectional view taken along the line E-E in Figure 9(a), showing the case where the base layer 111 is mainly composed of a resin layer or a paper-like layer. Figure 9(c) is a cross-sectional view taken along the line E-E in Figure 9(a), showing the case where the base layer 111 is composed of a combination of a resin layer 111a and a paper-like layer 111b. The laminated structure of each blank 101, 102 is the same as the laminated structure of the first embodiment, so its explanation is omitted here.

[0083] In the composite container 1B of the second embodiment, the loop stiffness of the cylindrical portion 12, as measured by the loop stiffness measurement method described above, is set to 20 to 900 mN / 15 mm width. When the cylindrical portion 12 is made of resin, it is preferable that the loop stiffness is 100 to 130 mN / 15 mm width and the coefficient of dynamic friction is 0.20 to 0.50.

[0084] Figure 10 is an explanatory diagram of the bonding state of the cylindrical portion 12 to the resin skeleton 11. Figure 10(a) schematically shows the end face when the main part of the housing portion 2 is cut along the horizontal plane. Figure 10(b) is an enlarged view of portion F in Figure 10(a).

[0085] As shown in Figure 10(a), the cylindrical portion 12 is formed by bending a strip-shaped first blank 101, which is relatively longer in the vertical direction compared to the horizontal direction in Figure 9(a), into a semi-cylindrical shape so that one end and the other end in the longitudinal direction are brought closer together. The portion on one end and the portion on the other end of the first blank 101 are integrally joined to the columnar skeleton portion 23, and are also integrally joined to the second upper annular wall portion 31b and the lower annular wall portion 33 adjacent to each other in the longitudinal direction (vertical direction) of the columnar skeleton portion 23.

[0086] As shown in Figure 10(b), the cylindrical portion 12 and the columnar skeletal portion 23 are fused together and integrated via the inner sealant layer 112 of the sheet material S. This reduces the amount of resin used to constitute the resin skeleton 11, while ensuring the required rigidity on the circumferential surface of the housing portion 2 by supporting key points of the cylindrical portion 12 with the columnar skeletal portion 23.

[0087] FIG. 11 is an explanatory view regarding the ratio of the surface area of a specific part of the housing portion 2. In FIG. 11, an end view when the main part of the housing portion 2 is cut along a vertical plane is schematically shown. As described above, the second upper annular wall portion 31b is formed by integrally connecting the thick annular wall portion 41 and the thin annular wall portion 42 vertically (refer to the main part cut end view of FIG. 8). In FIG. 11, the thickness relationship between the thick annular wall portion 41 and the thin annular wall portion 42 constituting the second upper annular wall portion 31b is schematically simplified and drawn with the same thickness. In an actual product, the cylindrical portion 12 is wound around the thin annular wall portion 42 and joined. The surface area (A), surface area (B), and surface area (C) used in the following description are defined as follows. The surface area (A) is the surface area (excluding the inside of the housing portion 2) of the portion of the cylindrical portion 12 that contacts the housing space 2d of the housing portion 2. That is, in FIG. 11, it is the area indicated by the symbol "R Ａ " in the figure, and it is the outer surface area of the portion that closes the side opening formed by being surrounded by the second upper annular wall portion 31b, the lower annular wall portion 33, and the columnar skeleton portion 23 adjacent in the radial direction (circumferential direction) of the resin skeleton 11 in the cylindrical portion 12. The surface area (B) is, in FIG. 11, the area indicated by the one-dot chain line with the symbol "R Ｂ " attached in the figure, and it is the area of the surface on the side facing the outside of the housing portion 2 in the upper annular skeleton portion 21 of the resin skeleton, which is the sum of the surface area of the flat portion on the outer peripheral side wall surface of the first upper annular wall portion 31a and the surface area of the convex portion (thread crest portion) and the concave portion (thread valley portion) between adjacent convex portions in the portion where the male screw 25 is formed. Since the surface area of the upper surface of the first upper annular wall portion 31a is sufficiently small compared to the outer peripheral side surface area of the first upper annular wall portion 31a, it has no influence even if it is not included in the surface area (B). The surface area (C) is the area indicated by the dotted line with the symbol "R Ｃ " attached in the figure, and it is the surface area of the outer peripheral side wall surface of the second upper annular wall portion 31b.

[0088] In the composite container 1B of the second embodiment, similar to the composite container 1A of the first embodiment, the surface area (A) is set to 50% or more of the surface area (A + B + C) obtained by adding surface area (A), surface area (B), and surface area (C) above the upper end of the lower skeletal portion 22, i.e., the upper end of the lower annular wall portion 33, i.e., the surface area (excluding the inside of the housing portion 2). By setting it in this way, the amount of resin used can be reliably reduced.

[0089] <Method for Manufacturing Composite Containers> The composite container 1B of the second embodiment can also be manufactured using the same method as the composite container 1A of the first embodiment.

[0090] In the composite container 1B of the second embodiment described above, the same effects and advantages as those of the composite container 1A of the first embodiment can be obtained.

[0091] Although the composite container of the present invention has been described above based on several embodiments, the present invention is not limited to the configuration described in the above embodiments, and its configuration can be modified as appropriate without departing from the spirit of the invention.

[0092] The following describes examples of the composite container of the present invention. However, the present invention is not limited to these examples.

[0093] <Example 1> As the sheet material S constituting the first blank 101 and the second blank 102, a laminate was used which was formed by bonding a base layer (barrier OPP20) 111 with a thickness of 20 μm, which is made by laminating a barrier layer on a resin film (biaxially oriented polypropylene film), an inner sealant layer (CPP60) 112 with a thickness of 60 μm, which is made of unoriented polypropylene film and is provided adjacent to the base layer 111 on the inside of the housing 2, and a surface resin layer (OPP40) 113 with a thickness of 40 μm, which is made of biaxially oriented polypropylene film and is provided adjacent to the base layer 111 on the outside of the housing 2, using a two-component curing urethane-based dry laminate adhesive. The first blank 101 and the second blank 102 obtained by subjecting the sheet material S made of the laminate to a predetermined punching process were used as insert parts in an insert molding method to form a resin skeleton 11 made of polypropylene resin, and the composite container of Example 1 was manufactured. The composite container of Example 1 has a rectangular shape similar to the composite container 1A of the first embodiment, the sealing structure between the storage section 2 and the lid 3 is a heat seal type, the surface area ratio [A / (A+B+C)×100] is set to 70%, and the loop stiffness is set to 100 mN / 15 mm width.

[0094] <Example 2> The sheet material S used in Example 1 was used as the sheet material S constituting the first blank 101 and the second blank 102. The first blank 101 and the second blank 102 obtained by subjecting the sheet material S to a predetermined punching process were used as insert parts in an insert molding method to form a resin skeleton 11 made of polypropylene resin, thereby producing the composite container of Example 2. The composite container of Example 2 has a round shape like the composite container 1B of the second embodiment, the sealing structure between the storage section 2 and the lid 3 is of the heat seal type, the surface area ratio [A / (A+B+C)×100] is set to 70%, and the loop stiffness is set to 100mN / 15mm width.

[0095] <Example 3> The composite container of Example 3 differs from the composite container of Example 2 in that the sealing structure between the storage section 2 and the lid 3 is screw-type, but otherwise it is the same as Example 2.

[0096] <Example 4> The composite container of Example 4 differs from the composite container of Example 2 in that the sealing structure between the storage section 2 and the lid 3 is of the snap-fit ​​type, but otherwise it is the same as Example 2.

[0097] <Example 5> The composite container of Example 5 differs from the composite container of Example 4 in that it does not have a surface resin layer (OPP40) 113, the inner sealant layer 112 is made of an unoriented polypropylene film (CPP30) with a thickness of 30 μm, and the loop stiffness is set to 20 mN / 15 mm width, but otherwise it is the same as Example 4.

[0098] <Example 6> The composite container of Example 6 has a surface resin layer 113 made of a biaxially oriented polypropylene film (OPP20) with a thickness of 20 μm, and a paper basis weight of 140 g / m². ２ The paper quality layer (paper 140 [g / m²] ２ This composite container differs from that of Example 4 in that the base layer 111 is formed by a composite layer which is created by laminating a barrier layer on a resin film (biaxially oriented polypropylene film) 111a with a thickness of 20 μm (barrier OPP 20) using a two-component curing urethane-based dry laminate adhesive, and the loop stiffness is set to 890 mN / 15 mm width. Otherwise, it is the same as that of Example 4.

[0099] <Example 7> The composite container of Example 7 differs from the composite container of Example 3 in that its surface area ratio [A / (A+B+C)×100] is 50%, but otherwise it is the same as that of Example 3.

[0100] <Example 8> The composite container of Example 8 differs from the composite container of Example 4 in that its surface area ratio [A / (A+B+C)×100] is 45%, but otherwise it is the same as that of Example 4.

[0101] <Comparative Example 1> As the sheet material S constituting the first blank 101 and the second blank 102, a laminate composed of a polyethylene terephthalate film (PET 12) with a thickness of 12 μm and an unoriented polypropylene film (CPP 30) with a thickness of 30 μm was used. The first blank 101 and the second blank 102 obtained by subjecting the sheet material S made of the laminate to a predetermined punching process were used as insert parts in an insert molding method to mold a resin skeleton 11 made of polypropylene resin, thereby producing the composite container of Comparative Example 1. The composite container of Comparative Example 1 has a rectangular shape similar to the composite container 1A of the first embodiment, the sealing structure between the storage section 2 and the lid 3 is of the heat-seal type, the surface area ratio [A / (A+B+C)×100] is set to 70%, and the loop stiffness is set to 19 mN / 15 mm width.

[0102] <Comparative Example 2> The sheet material S constituting the first blank 101 and the second blank 102 is a paper with a basis weight of 200 g / m². ２ The paper quality layer (paper 200 [g / m²] ２ A laminate was used, consisting of 111b, a resin layer (barrier OPP20) 111a with a thickness of 20 μm, which is formed by laminating a barrier layer on a resin film (biaxially oriented polypropylene film), and a 40 μm thick unoriented polypropylene film (CPP40). A resin skeleton 11 made of polypropylene resin was molded by an insert molding method using a first blank 101 and a second blank 102 obtained by subjecting a sheet material S made of the laminate to a predetermined punching process, and a composite container of Comparative Example 2 was produced. The composite container of Comparative Example 2 has a rectangular shape like the composite container 1A of the first embodiment, the sealing structure between the storage section 2 and the lid 3 is of the heat seal type, the surface area ratio [A / (A+B+C)×100] is set to 70%, and the loop stiffness is set to 950 mN / 15 mm width.

[0103] <Comparative Example 3> A composite container of Comparative Example 3 was manufactured by an insert molding method in which the sheet material S used in Comparative Example 2 was used as the sheet material S constituting the first blank 101 and the second blank 102, and the first blank 101 and the second blank 102 obtained by subjecting the sheet material S to a predetermined punching process were used as insert products to form a resin skeleton 11 made of polypropylene resin. The composite container of Comparative Example 3 has a round shape like the composite container 1B of the second embodiment, the sealing structure between the storage section 2 and the lid 3 is of the snap-fit ​​type, the surface area ratio [A / (A+B+C)×100] is set to 70%, and the loop stiffness is set to 950 mN / 15 mm width.

[0104] The composite containers of Examples 1 to 8 and Comparative Examples 1 to 3 were evaluated for the following evaluation levels for each evaluation item: opening deformation, leakage rate of the sealed structure, leakage in drop tests, and resin reduction rate.

[0105] (Opening Deformation) The opening diameters of the upper annular skeletal portion 21 that forms the contour of the opening in the composite container were measured in two mutually orthogonal directions (N (number of samples) = 5), and the geometric mean of the difference in the opening diameters in these two directions was calculated. Products with a difference of 0.5 mm or less from the design value were evaluated as good products, and those exceeding 0.5 mm were evaluated as defective products.

[0106] (Leakage rate of sealed structure) The container 2 was sealed by attaching a lid 3, and the leakage rate was determined by using a leak test liquid to find the percentage of composite containers that leaked relative to N (=10).

[0107] (Leakage due to drop test) A composite container, with a lid 3 attached to a water-filled container 2 to seal it, was dropped upright from a height of 1 m to check for leaks (N=10). If even one composite container leaked water, it was evaluated as defective.

[0108] (Resin Reduction Rate) The resin reduction rate does not directly affect the performance of the container and is therefore not necessarily a parameter that defines the technical scope of the present invention, but it is important in terms of decarbonization. The reduction rate of resin usage was evaluated when comparing the shape of the containment section 2 with a resin container manufactured by conventional injection molding of the same shape. The evaluation criteria are as follows: A: Reduction of 30% or more B: Reduction of less than 30% to 15% or more C: Reduction of less than 10% (no significant reduction effect)

[0109] Table 1 below shows the evaluation results for the composite containers of Examples 1 to 8 and Comparative Examples 1 to 3, including opening deformation, leakage rate of the sealed structure, leakage in drop tests, and resin reduction rate.

[0110]

[0111] As shown in Table 1, the composite containers of Examples 1 to 8 all received a "good" evaluation for opening deformation and had a leakage rate of 0%. In the composite containers of Examples 1 to 8, the loop stiffness did not exceed the upper limit of the numerical range defined in the present invention (900 mN / 15 mm width). Therefore, the rigidity of the cylindrical portion 12 was not too high, and deformation of the resin skeleton 11 due to the force that causes the cylindrical portion 12 to return to a flat shape was suppressed, and as a result, sufficient airtightness with the lid 3 could be ensured.

[0112] The composite containers of Examples 1 to 8 all received a "good" rating for leakage in drop tests. In the composite containers of Examples 1 to 8, the loop stiffness is equal to or greater than the lower limit of the numerical range specified in the present invention (20 mN / 15 mm width). Therefore, the rigidity of the cylindrical portion 12 is not too low, and the rigidity of the circumferential portion of the storage portion 2 can be ensured to a certain extent. As a result, when contents are filled into the storage portion 2, it is possible to prevent the circumferential portion of the storage portion 2 from expanding excessively, and even if an impact such as a drop from a certain height is applied, it is possible to prevent the circumferential portion of the storage portion 2 from being damaged, thereby ensuring sufficient functionality and durability as a container.

[0113] The composite containers of Examples 1 to 6 had a surface area ratio [A / (A+B+C)] of 70% and an evaluation of "A" for resin reduction rate, while the composite container of Example 7 had a surface area ratio [A / (A+B+C)] of 50% and an evaluation of "B" for resin reduction rate, demonstrating that the amount of resin used could be reduced by a certain amount or more. On the other hand, the composite container of Example 8 had a surface area ratio [A / (A+B+C)] of 45% and an evaluation of "C" for resin reduction rate. From these results, although there is no direct impact on the performance of the container, from the viewpoint of decarbonization, it can be said that a surface area ratio [A / (A+B+C)] of 50% or more is preferable.

[0114] In contrast, the composite container of Comparative Example 1 ruptured at the cylindrical portion 12 during the drop test. In the composite container of Comparative Example 1, the loop stiffness is 19 mN / 15 mm width, which is smaller than the lower limit of the numerical range (20 mN / 15 mm width) specified in the present invention. As a result, the rigidity of the cylindrical portion 12 is too low, and the rigidity of the circumferential portion of the housing 2 cannot be sufficiently secured, resulting in insufficient durability against impacts such as drops.

[0115] The composite containers of Comparative Examples 2 and 3 were evaluated as "poor" in terms of opening deformation, with leakage rates of 70% and 50%, respectively. In the composite containers of Comparative Examples 2 and 3, the loop stiffness exceeded the upper limit of the numerical range defined in the present invention (900 mN / 15 mm width), reaching 950 mN / 15 mm width. As a result, the rigidity of the cylindrical portion 12 was too high, causing the resin skeleton 11 to deform due to the force that tries to return the cylindrical portion 12 to a flat shape, and thus it was not possible to ensure sufficient airtightness with the lid 3 when the lid 3 was attached to the housing portion 2.

[0116] <Example 9> As the sheet material S constituting the first blank 101 and the second blank 102, a laminate was used which was formed by bonding a base layer (barrier OPP20) 111 with a thickness of 20 μm, which is made by laminating a barrier layer on a resin film (biaxially oriented polypropylene film), an inner sealant layer (CPP60) 112 with a thickness of 60 μm, which is made of unoriented polypropylene film and is provided adjacent to the base layer 111 on the inside of the housing 2, and a surface resin layer (OPP40) 113 with a thickness of 40 μm, which is made of biaxially oriented polypropylene film and is provided adjacent to the base layer 111 on the outside of the housing 2, using a two-component curing urethane-based dry laminate adhesive. The first blank 101 and the second blank 102 obtained by subjecting the sheet material S made of the laminate to a predetermined die-cutting process were used as insert parts in an insert molding method to form a resin skeleton 11 made of polypropylene resin, and the composite container of Example 9 was manufactured. The composite container of Example 9 has a rectangular shape similar to the composite container 1A of the first embodiment, the sealing structure between the housing 2 and the lid 3 is a heat seal type, the surface area ratio [A / (A+B+C)×100] is 70%, the loop stiffness is 100 mN / 15 mm width, and the dynamic friction coefficient of the sheet material S to the resin skeleton 11, measured in accordance with JIS K7125, is set to 0.35.

[0117] <Example 10> The composite container of Example 10 differs from the composite container of Example 9 in that its loop stiffness is 110 mN / 15 mm width, but otherwise it is the same as that of Example 9.

[0118] <Example 11> The composite container of Example 11 differs from the composite container of Example 9 in that its loop stiffness is 115 mN / 15 mm width, but otherwise it is the same as that of Example 9.

[0119] <Example 12> The composite container of Example 12 differs from the composite container of Example 9 in that its loop stiffness is 120 mN / 15 mm width, but otherwise it is the same as that of Example 9.

[0120] <Example 13> The composite container of Example 13 differs from the composite container of Example 9 in that its loop stiffness is 125 mN / 15 mm width, but otherwise it is the same as that of Example 9.

[0121] <Example 14> The composite container of Example 14 differs from the composite container of Example 9 in that its loop stiffness is 130 mN / 15 mm width, but otherwise it is the same as that of Example 9.

[0122] <Example 15> The composite container of Example 15 differs from the composite container of Example 9 in that its loop stiffness is 115 mN / 15 mm width and its dynamic friction coefficient is 0.20, but otherwise it is the same as that of Example 9.

[0123] <Example 16> The composite container of Example 16 differs from the composite container of Example 9 in that its loop stiffness is 115 mN / 15 mm width and its dynamic friction coefficient is 0.30, but otherwise it is the same as that of Example 9.

[0124] <Example 17> The composite container of Example 17 differs from the composite container of Example 9 in that its loop stiffness is 115 mN / 15 mm width and its dynamic friction coefficient is 0.40, but otherwise it is the same as that of Example 9.

[0125] <Example 18> The composite container of Example 18 differs from the composite container of Example 9 in that its loop stiffness is 115 mN / 15 mm width and its dynamic friction coefficient is 0.50, but otherwise it is the same as that of Example 9.

[0126] <Comparative Example 4> The composite container of Comparative Example 4 differs from the composite container of Example 9 in that its loop stiffness is 95 mN / 15 mm width, which is smaller than the lower limit of 100 mN / 15 mm width defined in the present invention when the cylindrical portion 12 is made of resin, but otherwise it is the same as that of Example 9.

[0127] <Comparative Example 5> The composite container of Comparative Example 5 differs from the composite container of Example 9 in that its loop stiffness is 135 mN / 15 mm width, which is above the upper limit of 130 mN / 15 mm width defined in the present invention when the cylindrical portion 12 is made of resin, but otherwise it is the same as that of Example 9.

[0128] <Comparative Example 6> The composite container of Comparative Example 6 differs from the composite container of Example 9 in that its loop stiffness is 115 mN / 15 mm width and its coefficient of dynamic friction is 0.15, which is smaller than the lower limit of 0.20 defined in the present invention when the cylindrical portion 12 is made of resin. Otherwise, it is the same as that of Example 9.

[0129] <Comparative Example 7> The composite container of Comparative Example 7 differs from the composite container of Example 9 in that its loop stiffness is 115 mN / 15 mm width and its dynamic friction coefficient is 0.55, which is higher than the upper limit of 0.50 specified in the present invention when the cylindrical portion 12 is made of resin. Otherwise, it is the same as that of Example 9.

[0130] For the composite containers of Examples 9 to 18 and Comparative Examples 4 to 7 described above, in addition to the evaluation items of opening deformation, leakage rate of the sealed structure, leakage in drop tests, and resin reduction rate, stiffness and slipperiness were evaluated at the following evaluation levels.

[0131] (Strength) A: The cylindrical part is very easy to wrap around the resin frame, and there is almost no deformation of the resin frame. B: The cylindrical part is easy to wrap around the resin frame, or the resin frame deforms slightly, but sufficient airtightness with the lid can be ensured. C: It is difficult to wrap the cylindrical part around the resin frame, which poses a manufacturing problem, or the resin frame deforms so much that sufficient airtightness with the lid cannot be ensured.

[0132] (Slipperiness) A: There is almost no misalignment of the sheet material relative to the resin frame, handling is very good, and production efficiency can be greatly improved. B: There is almost no misalignment of the sheet material relative to the resin frame, or even if there is some, it does not cause manufacturing problems, or handling is good and production efficiency can be improved. C: There is a large misalignment of the sheet material relative to the resin frame, which causes manufacturing problems, or handling is difficult and production efficiency is greatly reduced.

[0133] Table 2 below shows the evaluation results for the composite containers of Examples 9 to 18 and Comparative Examples 4 to 7, including opening deformation, leakage rate of the sealed structure, leakage in drop tests, resin reduction rate, rigidity, and slipperiness.

[0134]

[0135] As shown in Table 2, the composite containers of Examples 9 to 18 have an evaluation of "Good" for opening deformation, a leakage rate of 0%, an evaluation of "Good" for leakage in drop tests, and an evaluation of "A" for resin reduction rate. In addition, their rigidity is evaluated as "A" or "B," and their slipperiness is evaluated as "A" or "B." In the composite containers of Examples 9 to 18, the loop stiffness is within the appropriate numerical range (100 to 130 mN / 15 mm width) defined in the present invention when the cylindrical part 12 is made of resin. Therefore, the cylindrical part 12 can be easily wrapped around the resin skeleton 11, and the wrapped state is maintained, contributing to improved appearance. Furthermore, deformation of the resin skeleton 11 can be suppressed, ensuring sufficient airtightness with the lid 3. Furthermore, in the composite containers of Examples 9 to 18, the coefficient of dynamic friction is within the appropriate numerical range (0.20 to 0.50) specified in the present invention when the cylindrical portion 12 is made of resin. This makes it easier to position the sheet material S relative to the resin skeleton 11, improves handling, and increases production efficiency.

[0136] In contrast, both the composite container of Comparative Example 4 and the composite container of Comparative Example 5 received a "C" rating for rigidity. In the composite container of Comparative Example 4, the loop stiffness is 95 mN / 15 mm width, which is smaller than the lower limit of 100 mN / 15 mm width defined in the present invention when the cylindrical portion 12 is made of resin. As a result, the rigidity of the cylindrical portion 12 is too low, making it difficult to wrap the cylindrical portion 12 around the resin skeleton 11, and even if it is wrapped, the wrapped state cannot be maintained. In the composite container of Comparative Example 5, the loop stiffness is 135 mN / 15 mm width, which exceeds the upper limit of 130 mN / 15 mm width defined in the present invention when the cylindrical portion 12 is made of resin. As a result, the rigidity of the cylindrical portion 12 is too high, causing the resin skeleton 11 to deform to such an extent that sufficient airtightness with the lid 3 cannot be ensured.

[0137] Both the composite container of Comparative Example 6 and the composite container of Comparative Example 7 received a "C" rating for slipperiness. In the composite container of Comparative Example 6, the dynamic friction coefficient is 0.15, which is smaller than the lower limit of 0.20 specified in the present invention when the cylindrical portion 12 is made of resin. As a result, the sheet material S may shift position relative to the resin skeleton 11, and handling becomes poor, such as making it difficult to bundle the sheet material S and transport it to the machine during insert molding, thus reducing production efficiency. In the composite container of Comparative Example 7, the dynamic friction coefficient is 0.55, which exceeds the upper limit of 0.50 specified in the present invention when the cylindrical portion 12 is made of resin. As a result, the sheet material S becomes excessively difficult to slide relative to the resin skeleton 11, leading to poor handling, such as making it difficult to remove the sheet material S from the magazine where the sheet material S is accumulated during insert molding, thus reducing production efficiency.

[0138] The composite container of the present invention can be used, for example, to contain food, pharmaceuticals, industrial products, and the like.

[0139] 1A, 1B Composite container 2 Containing section 11 Resin skeleton 12 Cylindrical section 21 Upper annular skeleton section 22 Lower skeleton section 23 Columnar skeleton section 111 Base material layer 111a Resin layer 111b Paper-like layer 112 Inner sealant layer 113 Surface resin layer S Sheet material

Claims

1. A composite container having a housing section having a bottom surface, a circumferential surface and an opening, comprising: a resin skeleton forming the framework of the housing section; and a cylindrical section including a sheet material forming the circumferential surface of the housing section, which is joined to the resin skeleton in a bent state, wherein the cylindrical section is a loop-shaped sample piece with a circumference of 100 mm, and the loop stiffness measured when the sample piece is pressed in for a pressing length of 10 mm is 20 to 900 mN / 15 mm width.

2. The composite container according to claim 1, wherein the sheet material comprises a base material layer and an inner sealant layer provided adjacent to the base material layer and inside the housing portion.

3. The composite container according to claim 2, further comprising a surface resin layer provided adjacent to the base material layer and on the outside of the housing portion.

4. The composite container according to claim 2 or 3, wherein the base layer comprises a resin layer and / or a paper-like layer.

5. The composite container according to claim 2 or 3, wherein the resin skeleton comprises an upper annular skeleton portion that forms the contour of the opening and a columnar skeleton portion connected to the upper annular skeleton portion, and the columnar skeleton portion is fused and integrated with the inner sealant layer.

6. The composite container according to claim 3, wherein in the portion where one end and the other end of the sheet material overlap, the inner sealant layer on one end of the sheet material and the surface resin layer on the other end are fused together to form a single unit.

7. The composite container according to claim 5, wherein the resin skeleton further has a lower skeleton connected to the lower side of the upper annular skeleton via the columnar skeleton, and the surface area of ​​the portion of the cylindrical part that is in contact with the internal space of the housing (excluding the inside of the housing) is 50% or more of the surface area of ​​the housing above the upper end of the lower skeleton (excluding the inside of the housing).

8. The composite container according to claim 2 or 3, wherein the base material layer does not include a paper-like layer, includes a resin layer, and the loop stiffness is 100 to 130 mN / 15 mm width.

9. The composite container according to claim 2 or 3, wherein the base material layer does not include a paper layer, but includes a resin layer, and the coefficient of dynamic friction of the sheet material with respect to the resin skeleton, as measured in accordance with JIS K7125, is 0.20 to 0.

50.

10. A composite container according to any one of claims 1 to 3, wherein the container is configured to contain a specific resin, and when the content of the specific resin in the entire container is a1 (parts by mass) and the content of materials other than the specific resin in the entire container is a2 (parts by mass), the monomaterial ratio M, expressed by the following formula (1): M = a1 / (a1+a2) × 100 ... (1), is configured to be 80% or more.

11. The composite container according to claim 10, wherein the specific resin is polypropylene (PP).

12. A composite container according to any one of claims 1 to 3, wherein the container is composed of paper, and the paper content ratio, which is the ratio of the mass of paper to the total mass of the container, is 50% or more.

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