container

Abstract

To provide a paper-resin composite container that allows the liquid level of its contents to be checked from the outside. [Solution] A paper-resin composite container according to one embodiment comprises a storage section with an open top for containing liquid contents, and a lid attached to the top of the storage section. The storage section has a resin skeleton and a main body integrated with the resin skeleton, including a bottom and sides. The parallel light transmittance of the resin forming the resin skeleton is 18% or more. The bottom and sides include a paper layer and a heat-sealed layer laminated on the paper layer. Slits are formed on the sides in a direction intersecting the bottom. The resin skeleton has side columnar portions that close the slits, and at least a part of the side columnar portions is a liquid level confirmation area for checking the liquid level of the contents.

Description

Technical Field

[0001] The present invention relates to a container.

Background Art

[0002] As a container for reducing environmental impact, there is a composite container containing paper and resin. Patent Documents 1 to 3 disclose a composite container in which a main body portion composed of a blank plate containing at least paper and a resin framework (resin skeleton portion) are integrated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] The composite containers described in Patent Documents 1 to 3 have an open upper portion. When containing a liquid content in the container, usually, the upper portion of the composite container is closed with a lid. Hereinafter, for convenience of explanation, the composite container to which the lid is attached is referred to as a housing portion. The outer surface of the housing portion (the composite container described in Patent Documents 1 to 3) containing the liquid content includes paper and is usually printed over the entire outer surface, so the liquid content cannot be visually recognized when the housing portion is covered with a lid. On the other hand, there is a user's desire such as wanting to check the remaining amount of the liquid content in the state where the lid is on.

[0005] One object of the present disclosure is to provide a container that contains paper and allows the liquid level position of the liquid content to be confirmed from the outside.

Means for Solving the Problems

[0006] [1] A container according to one aspect of the present disclosure comprises a storage section having an open top for storing liquid contents, and a lid attached to the top of the storage section, wherein the storage section has a resin skeleton and a main body integrated with the resin skeleton, the parallel light transmittance of the resin forming the resin skeleton is 18% or more, the bottom and the sides include a paper layer and a heat-sealed layer laminated on the paper layer, the sides have slits extending in a direction intersecting the bottom, the resin skeleton has side columnar portions that close the slits, and at least a part of the side columnar portions is a liquid level confirmation area for confirming the liquid level of the liquid contents.

[0007] In the above-described container, the parallel light transmittance of the resin forming the resin skeleton is 18% or more, and the resin skeleton has side column sections including a liquid level confirmation area. Therefore, the liquid level of the contents can be confirmed from the outside by utilizing the liquid level confirmation area in the side column sections.

[0008] [2] In the container described in [1] above, the inner surface of the liquid level confirmation area may be rough. In this case, it is easier to confirm the liquid level of the liquid contents.

[0009] [3] In the container described in [2] above, the rough surface may be a pear-shaped surface.

[0010] [4] In the container described in [2] or [3] above, the absolute value of the difference between the haze value of the liquid level confirmation area when the inner surface is wet with water and when it is not wet with water may be 10.0% or more.

[0011] [5] In the container described in any of [1] to [4] above, the entire side column portion may be the liquid level confirmation area.

[0012] [6] In the container according to any one of [1] to [5] above, the main body portion is a three-dimensional blank in which a container blank is three-dimensionally bent. The container blank has a bottom panel corresponding to the bottom surface and at least one side panel corresponding to the side surface and connected to the peripheral edge of the bottom panel. In the three-dimensional blank, the side panel may be bent with respect to the bottom panel.

Advantages of the Invention

[0013] According to the present invention, it is possible to provide a container that contains paper and allows the liquid level position of the liquid content to be confirmed from the outside.

Brief Description of the Drawings

[0014] [Figure 1] FIG. 1 is a perspective view of a container according to an embodiment. [Figure 2] FIG. 2 is a perspective view of the storage portion of the container shown in FIG. 1. [Figure 3] FIG. 3 is a plan view of an example of a container blank forming the storage portion shown in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view showing an example of the layer structure of the container blank shown in FIG. 3. [Figure 5] FIG. 5 is a cross-sectional view taken along the line V-V of the resin skeleton portion of the container shown in FIG. 1. [Figure 6] FIG. 6 is a schematic view of the storage portions of Experimental Examples 1 to 13 and Experimental Examples 15 to 19. [Figure 7] FIG. 7 is a schematic view of a box body that is a model of the storage portion for evaluating the liquid level visibility. [Figure 8] FIG. 8 is a chart showing the results of Experimental Examples 1 to 14. [Figure 9] FIG. 9 is a chart showing the results of Experimental Examples 15 to 19.

Modes for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. However, the present disclosure is not limited to the following embodiments. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate.

[0016] Referring to FIG. 1, a container 1 according to an embodiment will be described. FIG. 1 is an exploded perspective view of a container according to an embodiment.

[0017] The container 1 is a container for accommodating a liquid content in an internal space S. In the present embodiment, the liquid content accommodated in the container 1 is a liquid. The liquid content may be food or non-food. The liquid content may be, for example, a beverage such as water, tea, juice, lactic acid bacteria beverage, or liquor. The liquid content portion may be lotion. The liquid content may be a viscous liquid (for example, a gel-like substance).

[0018] The container 1 has an internal space S and includes a storage portion 2 with an open upper portion. The container 1 has a lid 3 for closing the storage portion 2. Since the liquid content is stored in the storage portion 2, the storage portion 2 is the container body. The lid 3 may be detachably attached to the upper portion of the storage portion 2.

[0019] [Storage portion] The storage portion 2 has a main body portion 20 and a resin skeleton portion 30, and is configured by integrating the main body portion 20 and the resin skeleton portion 30. The main body portion 20 includes a predetermined amount of paper layers. Therefore, the storage portion 2 is a composite of paper and resin (paper-resin composite).

[0020] [Main body portion] The main body portion 20 is a wall surface portion that substantially defines the internal space S. The surface area of the main body portion 20 may be 80% or more of the surface area of the storage portion 2.

[0021] An example of the external shape of the main body 20 is cylindrical, as shown in Figure 1. Other examples of the external shape of the main body 20 include a rectangular prism (see Figure 6). Examples of a rectangular prism include a cuboid, a cube, etc. The main body 20 may have a shape that widens towards the top, that is, the upper part of the main body 20 is wider than the lower part. In the following, unless otherwise specified, the description will refer to the cylindrical external shape of the main body 20 as shown in Figure 1.

[0022] Figure 2 is a perspective view of the main body 20. Specifically, Figure 2 is a drawing in which the resin frame 30 of the housing 2 shown in Figure 1 is omitted.

[0023] The main body 20 comprises a bottom surface 21 and side surfaces 22 rising from the bottom surface 21. The bottom surface 21 and side surfaces 22 correspond to the bottom surface and side surfaces of the housing section 2. The bottom surface 21 and side surfaces 22 have shapes corresponding to the main body 20. In the configuration shown in Figure 2, the bottom surface 21 is circular, and the side surfaces 22 are cylindrical. The bottom surface 21 may be circular, elliptical, or have other shapes including a curved periphery. The side surfaces 22 may have a tapered shape, with the diameter increasing as it moves upward (away from the bottom surface 21).

[0024] The side surface 22 according to this embodiment has a pair of slits (gaps) 23 extending in a direction intersecting the bottom surface 21. The side surface 22 has a first portion 22A and a second portion 22B separated by the slits 23.

[0025] The main body portion 20 according to this embodiment is a three-dimensional blank obtained by making the container blank 10 shown in Figure 3 three-dimensional. The main body portion 20 may be a three-dimensional blank obtained by folding the container blank 10 in three dimensions. An example of the container blank 10 that forms the main body portion 20 will be explained using Figure 3.

[0026] As shown in Figure 3, the container blank 10 is formed to be flat overall. The container blank 10 includes at least a paper layer. The container blank 10 is manufactured by punching out a processed paper sheet containing the paper layer into an appropriate shape. Therefore, the layer structure is exposed on the entire perimeter of the end face of the container blank 10 (there is no layer extending in the thickness direction that covers the end face).

[0027] The container blank 10 comprises a bottom panel 11 corresponding to the bottom surface 21, a side panel 12A corresponding to the first portion 22A of the side surface 22, and a side panel 12B corresponding to the second portion 22B of the side surface 22.

[0028] The bottom panel 11 and the side panels 12A and 12B are integrally molded in a planar shape. The bottom panel 11 is, for example, a circular plate-like section. The side panels 12A and 12B are, for example, rectangular plate-like sections. Fold lines may be provided at the boundaries 16 of the bottom panel 11 and the two side panels 12A and 12B. In Figure 3, the boundaries 16 are shown with dashed lines to distinguish them from the cuts 15 described later, but the boundaries 16 may be substantially linear.

[0029] The side panels 12A and 12B are connected to opposite (180-degree offset) portions of the peripheral edge 11e of the bottom panel 11. The side panels 12A and 12B are, for example, of the same size and shape. The side panels 12A and 12B may be formed symmetrically with respect to a virtual plane (a plane perpendicular to the bottom panel 11) that passes through the center of the bottom panel 11 and is at equal distances from the two boundary portions 16.

[0030] Each of the side panels 12A and 12B includes a bottom edge portion 12f that is slightly shorter than half the circumference of the bottom panel 11 (a length equivalent to half a circumference). Each of the side panels 12A and 12B also includes a top edge portion 12e that is opposite to the bottom edge portion 12f. The length of the top edge portion 12e may be the same as the length of the bottom edge portion 12f. The top edge portion 12e is parallel to the bottom edge portion 12f. The top edge portion 12e and the bottom edge portion 12f may be curved. Each of the side panels 12A and 12B has a side edge portion 12g that connects the bottom edge portion 12f and the top edge portion 12e, and has an appropriate length corresponding to the height of the main body portion 20.

[0031] A straight cut 15 may be formed along the boundary 16 between each of the side panels 12A and 12B and the bottom panel 11. The cut 15 does not reach both ends of the boundary 16 (both ends of the folding line), but is formed only near the center of the boundary. In other words, the cut 15 is shorter than the boundary 16. The cut 15 may be formed to penetrate the entire layer structure of the container blank 10 (the entire thickness direction), or it may be formed only on a part of the inner or outer surface of the container blank 10 in the thickness direction (it does not have to penetrate). When a cut 15 (penetration portion) is provided, it is easier to make the container blank 10 three-dimensional.

[0032] The main body portion 20 (see Figure 3) is a three-dimensional blank formed by the side panels 12A and 12B of the container blank 10 being folded three-dimensionally relative to the bottom panel 11 at the boundary portion 16 with the bottom panel 11. As mentioned above, the bottom side edges 12f of the side panels 12A and 12B are slightly shorter than half the length of the circumference of the bottom panel 11 (a length equivalent to half a circumference). Therefore, in the main body portion 20, a slit 23 is created between the side panels 12A and 12B (in other words, between the first portion 22A and the second portion 22B) in the direction along the peripheral edge 11e of the bottom panel 11 (circumferential direction in Figure 3).

[0033] The bottom panel 11, side panel 12A, and side panel 12B of the container blank 10 correspond to the bottom surface 21, first section 22A, and second section 22B of the main body 20. The top edge portion 12e of side panel 12A and side panel 12B corresponds to the upper end surface 22e of the first section 22A and second section 22B, and the side edge portion 12g of side panel 12A and side panel 12B corresponds to the side end surface 22g of the first section 22A and second section 22B.

[0034] The container blank 10 has at least a paper layer. The layer structure of the container blank 10 is, for example, uniform throughout. The container blank 10 is manufactured by punching out a processed paper sheet (sheet-like body) containing at least a paper layer into an appropriate shape. Therefore, the layer structure is exposed on the end face around the entire circumference of the container blank 10 (there is no layer extending in the thickness direction that covers the end face). In one embodiment, the container blank 10 is a sheet-like body in which a barrier layer and a paper layer are laminated on a heat-sealed layer.

[0035] In the container blank 10, the paper layer content is, for example, 50% by weight or more, but may also be 60% by weight or more, or 70% by weight or more. A higher paper layer content in the container blank 10 is advantageous from the standpoint of reducing environmental impact.

[0036] The container blank 10 may further include at least one of a heat-welding layer and a barrier layer. The heat-welding layer is a layer that contributes to joining the container blank 10 to the resin skeleton 30. The barrier layer is a layer that blocks at least gas (e.g., oxygen). The barrier layer may also block moisture.

[0037] Referring to Figure 4, an example of the layer structure (laminated structure) of the container blank 10 will be described. As shown in Figure 4, the container blank 10 of this embodiment includes, for example, a protective layer 51, an ink layer 52, an outer sealant layer 54, a paper layer 55, an adhesive layer 53, a barrier layer 56, and an inner sealant layer 57, in order from the outer layer (outer surface side) to the inner layer (inner surface side).

[0038] The protective layer 51 is a layer that protects the ink layer 52 and the paper layer 55. The protective layer 51 may have heat-weld properties. The protective layer 51 may be formed from a thermoplastic resin, OP varnish, etc. If the protective layer 51 is a thermoplastic resin, examples of materials for the protective layer 51 include polyethylene resin, polypropylene resin, polyester resin, etc. The protective layer 51 is formed by film lamination, extrusion, coating, etc.

[0039] Known ink materials can be used for the ink layer 52. The suitability of the ink layer 52 is selected based on the desired appearance.

[0040] The paper layer 55 is a structural layer that provides strength to the container blank 10 (storage section 2). The type of paper used for the paper layer 55 is not limited. Considering printability, it is desirable to use double-sided glossy paper for the paper layer 55. An example of the paper layer 55 is double-sided coated paper. Water-resistant paper or oil-resistant paper may be used as needed.

[0041] The thickness of the paper layer 55 is, for example, within the range of 200 μm or more and 1000 μm or less. When the thickness of the paper layer 55 is 200 μm or more, it is possible to reduce the generation of burrs due to partial variations in the paper layer 55, or rigidity can be easily obtained, making it easier to ensure the strength of the container against drops, vibrations, etc. From a similar viewpoint, the thickness of the paper layer 55 may be 250 μm or more. By making the thickness of the paper layer 55 1000 μm or less, it is possible to reduce the rebound of the side surface 22 (side panel part) when forming a three-dimensional object, making it easier to ensure the roundness of the container.

[0042] The adhesive layer 53 is a layer for bonding the paper layer 55 and the barrier layer 56. The adhesive layer 53 may be formed as, for example, an extruded resin layer. The adhesive layer 53 may be formed from, for example, low-density polyethylene (LDPE). The adhesive layer 53 may also be formed from an adhesive. An example of an adhesive is a two-component curing urethane adhesive.

[0043] The barrier layer 56 is a layer in which a vapor-deposited layer 562 is formed on the support film layer 561. It is preferable that the barrier layer 56 be positioned on the inner surface side of the main body 20 than the paper layer 55.

[0044] The support film layer 561 is a substrate on which the vapor-deposited layer 562 is formed, and also serves as a layer to prevent tearing, ripping, etc. The support film layer 561 may be a stretched film. When the support film layer 561 is composed of a stretched film, the stretched state of the stretched film is not limited. The resin film may be a uniaxially stretched film or a biaxially stretched film. Examples of materials for the support film layer 561 include polyethylene terephthalate (PET), nylon (Ny), or polypropylene (PP). The tensile strength of the support film layer 561 is preferably 100 MPa or more, and more preferably 200 MPa or more. A tensile strength of 100 MPa or more makes it less likely for breakage to occur at the joints.

[0045] The support film layer 561 may be surface-treated. Surface treatment can improve adhesion with other layers (such as a vapor-deposited layer or anchor coat layer) when laminating them. As surface treatment, for example, (a) physical treatments such as corona treatment, plasma treatment, or flame treatment, or (b) chemical treatments such as chemical treatment with acids or alkalis may be used.

[0046] The vapor-deposited layer 562 is a layer formed on at least one side of the support film layer 561 in order to impart gas barrier properties to the container blank 10. In the embodiment shown in Figure 4, the vapor-deposited layer 562 is formed on the side of the support film layer 561 opposite to the paper layer 55, but it may also be formed on the side of the support film layer 561 that is on the paper layer 55 side, or on both sides.

[0047] The vapor-deposited layer 562 is a layer formed by depositing a vapor deposition material onto the support film layer 561. The vapor deposition material used for the vapor deposition layer may be appropriately selected from known inorganic materials that constitute gas barrier vapor-deposited films. Examples include metals such as Si, Al, Zn, Sn, Fe, and Mn, and inorganic compounds containing one or more of these metals. Examples of the above inorganic compounds include oxides, nitrides, carbides, and fluorides. Among these, at least one selected from metals and metal oxides is preferred. Specifically, for example, silicon oxides such as silicon monoxide and silicon dioxide (SiO₂) x Examples include aluminum oxide, magnesium oxide, and tin oxide.

[0048] An example of a barrier layer 56 including a support film layer 561 and a vapor deposition layer 562 is GL-PET manufactured by TOPPAN Corporation.

[0049] Instead of the vapor-deposited layer 562, a support film layer 561 with a barrier coating may be used as the barrier layer 56.

[0050] Although the formation of the barrier layer 56, which is composed of a support film layer 561 and a vapor-deposited layer 562, has been described, the container blank 10 may have a stretched film (support film layer 561) and a barrier layer laminated on the stretched film. When a barrier layer is provided separately from the stretched film, the barrier layer may be made of a barrier resin such as ethylene vinyl alcohol copolymer resin (EVOH), or it may be a metal foil (e.g., aluminum foil). The vapor-deposited layer or the barrier coat itself described above can also be referred to as the barrier layer.

[0051] In this embodiment, the outer sealant layer 54 and the inner sealant layer 57 are heat-weldable layers. The outer sealant layer 54 and the inner sealant layer 57 are layers for heat-welding the resin skeleton part 30 and the main body part 20 (or container blank 10). The resins forming the outer sealant layer 54 and the inner sealant layer 57 may be the same resin or different resins. Examples of resins forming the outer sealant layer 54 and the inner sealant layer 57 include low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE). The outer sealant layer 54 and the inner sealant layer 57 are formed by film lamination, extrusion, coating, etc.

[0052] When the container blank 10 has a protective layer 51 as its outermost layer, and a non-heat-weldable varnish or the like is used as the resin forming the protective layer 51, as shown in Figure 4, an outer sealant layer 54 is provided on the outside of the paper layer 55, and the ink layer 52 is omitted at the welding portion with the resin skeleton 30 (the portion connected to the resin skeleton 30 is not printed), thereby further ensuring heat-welding (sealing) with the resin skeleton 30.

[0053] If the outermost layer material of the container blank 10 (protective layer 51 in the example shown in Figure 4) has heat-weldability with the resin skeleton 30, the container blank 10 does not need to have an outer sealant layer 54.

[0054] Since the required airtightness, liquid tightness, and barrier properties of the containment section 2 vary depending on the liquid contents contained in the containment section 2, the layer configuration of the main body section 20 (container blank 10) should be appropriately changed and adjusted.

[0055] <Resin skeleton part> Referring to Figure 1, the resin frame portion 30 will be explained. The resin frame portion 30 covers the end face of the main body portion 20 and plays a role in forming the framework of the housing portion 2, ensuring strength, or constituting a part that is functionally necessary (and requires strength) for the housing portion 2.

[0056] The resin skeleton portion 30 is formed, for example, by injection molding. The resin skeleton portion 30 covers the end faces that are exposed in the housing portion 2. Examples of the exposed end faces are the side end faces 22g of the first portion 22A and the second portion 22B that are exposed to the slit 23, and the upper end faces 22e of the side surface 22 (first portion 22A and second portion 22B).

[0057] The resin skeleton portion 30 according to this embodiment has a lower annular portion 31, an upper annular portion 33, and two side column portions 32 that connect the lower annular portion 31 and the upper annular portion 33.

[0058] The lower annular portion 31 is a circular part formed along the boundary (edge) between the bottom surface 21 and the side surface 22. The lower annular portion 31 covers the peripheral end surface of the bottom surface 21 corresponding to the peripheral edge 11e of the bottom surface panel 11, the lower end surfaces of the first portion 22A and the second portion 22B2 corresponding to the bottom side edges 12f of the side panels 12A and 12B, and the notch 15.

[0059] The upper annular portion 33 is located above the side surface 22. The upper annular portion 33 is the part to which the lid 3 is attached. The upper end surface 22e of the side surface 22 (first portion 22A and second portion 22B) is covered by the upper annular portion 33.

[0060] On the outer surface of the upper annular portion 33, for example, a flange portion 36 and a threaded portion 37 are formed. Both the flange portion 36 and the threaded portion 37 protrude outward from the cylindrical surface of the upper annular portion 33. The flange portion 36 is formed around the entire circumference (over the entire circumferential direction) at the lower end of the upper annular portion 33. The threaded portion 37 is formed in a region above the flange portion 36, for example, in a part of the circumferential direction, and constitutes a multi-thread threaded portion. The threaded portion 37 may be formed around the entire circumference. At least one of the upper annular portion 33 and the flange portion 36 is formed to cover the upper end surface 22e of the side surface 22.

[0061] The two side column sections 32 connect the lower annular section 31 and the upper annular section 33. Each side column section 32 closes the corresponding slit 23. As a result, the side end faces 22g of the first section 22A and the second section 22B, which were exposed at the slit 23, are covered by the side column sections 32.

[0062] The material of the resin skeleton 30 is a resin with a parallel light transmittance Tb(%) of 18% or more. That is, the material of the resin skeleton 30 is a resin having a certain degree of transparency (at least semi-transparent). The parallel light transmittance Tb(%) may be the parallel light transmittance calculated by the following formula (1). Tb = (1 - α / 100) × Ta ···(1) In equation (1), α(%) and Ta(%) are the haze value and total light transmittance of the resin skeleton 30 material. The above haze value α(%) may be the value measured in accordance with "JIS K 7136:2000 Plastics - Method for determining haze of transparent materials". The above total light transmittance Ta(%) may be a value measured in accordance with "JIS K 7361-1: 1997 Plastics - Test method for total light transmittance of transparent materials - Part 1: Single beam method".

[0063] The parallel light transmittance Tb of the resin skeleton material 30 may be 20% or more, 45% or more, 50% or 60%.

[0064] "Material for the resin skeleton 30" refers to the material used when forming the resin skeleton 30. For example, if the resin skeleton 30 is formed by injection molding, the material for the resin skeleton 30 is the resin supplied to the injection molding die.

[0065] An example of the material for the resin skeleton 30 is a thermoplastic resin. Examples of materials for the resin skeleton 30 include polyolefins and polyesters. Examples of polyolefins include polyethylene (PE) and polypropylene (PP). Examples of polyesters include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN). A surfactant may be added to the material of the resin skeleton 30. An example of a surfactant is fatty acid surfactant.

[0066] The side column portion 32 has a liquid level confirmation area 321 for checking the liquid level of the liquid contents contained in the storage portion 2. In this embodiment, the entire side column portion 32 is the liquid level confirmation area 321. Since the liquid level confirmation area 321 is the part for checking the amount (or liquid level position) of the liquid contents, for example, the liquid level confirmation area 321 may be 2 / 3 or less or 1 / 2 or less of the height of the side column portion 32.

[0067] In this embodiment, the inner surface 321a of the liquid level confirmation area 321 is a rough surface with irregularities, as shown in Figure 5. An example of a rough surface is a pear-textured surface. The inner surface 321a may also be an irregular surface formed by arranging raised portions of a predetermined shape in a grid pattern. Examples of raised portions of a predetermined shape include square pyramids and triangular pyramids.

[0068] Because the inner surface 321a of the liquid level confirmation area 321 is rough, the liquid level confirmation area 321 exhibits a so-called frosted glass-like appearance.

[0069] The rough surface may be configured such that, for example, the haze value α(%) of the liquid level confirmation area 321 is 75% or more and 98% or less. The haze value α(%) of the liquid level confirmation area 321 may also be 80% or more and 95% or less. The above haze value α is the value when the inner surface 321a is not wetted with liquid.

[0070] The rough surface may be configured such that the absolute difference in the haze value of the liquid level confirmation area 321 when the inner surface 321a is wet with water and when it is not wet with water is 10.0% or more. That is, if the haze value of the liquid level confirmation area 321 when it is wet is denoted as haze value β (%), the difference between haze value α and haze value β may be 10.0% or more.

[0071] The parallel light transmittance Tb(%) of the liquid level confirmation area 321 may be 2% or more and 16% or less, or 3% or more and 16% or less. The parallel light transmittance Tb(%) of the liquid level confirmation area 321 may be 10% or less.

[0072] In this embodiment, since the entire side column portion 32 is the liquid level confirmation area 321, the inner surface 321a corresponds to the inner surface of the side column portion 32. Therefore, the inner surface 321a may also be referred to as the inner surface 321a of the side column portion 32.

[0073] Let L1 (mm) be the total circumference of the storage section 2, L2 (mm) be the width of the side column section 32, and let n (n is an integer greater than or equal to 1) be the number of side column sections 32 that the storage section 2 has. Then, when (n × L2) is the length L3, the ratio R (=L3 / L1) of the length L3 to the total circumference L1 may be 1% or more and 20% or less, or 1% or more and 5% or less.

[0074] The width L2 of the side column 32 is the length of the side column 32 along the circumferential direction of the housing section 2. In configurations where the size changes along the height direction, such as when the housing section 2 widens towards the top, the total circumference L1 and width L2 may be the lengths measured at the same height. The width of the side column 32 corresponds to the width of the slit 23 of the main body section 20 shown in Figure 3.

[0075] The above-mentioned housing section 2 is manufactured, for example, as follows:

[0076] When manufacturing the storage section 2, the main body (three-dimensional blank) 20 is formed by bending a flat container blank 10 (main body formation process). Specifically, multiple container blanks 10 are stacked and stored in a predetermined location. Meanwhile, in the injection molding apparatus, an injection molding die consisting of a female mold and a male mold arranged to face each other is prepared. The outer shapes of these molds and the container blanks 10 are designed to correspond in advance. One by one, the container blanks 10 are picked up by a gripping device having a gripping mechanism such as a suction mechanism, and the container blanks 10 are mounted on a dummy core having the same outer shape and size as the male mold. At this time, the inner surface of the container blank 10 comes into contact with the surface of the dummy core. The side panels 12 are bent relative to the bottom panel 11 to form the main body 20. The main body 20 thus formed is held on the dummy core.

[0077] After the main body forming process described above, a resin skeleton 30 integrated with the main body 20 is formed by injection molding (resin skeleton forming process). Specifically, a dummy core holding the main body 20 is inserted into the female mold, and the holding by the dummy core is released. The dummy core is removed, and the main body 20 is set in the female mold. At this time, the outer surface of the main body 20 abuts against the surface of the female mold. Each panel of the three-dimensional blank, which is the main body 20, is set in a predetermined position relative to the surface of the female mold. In this state, the male mold is inserted into the female mold. The clearance between the female mold and the male mold is narrowed, and the main body 20 is held in place. All end faces of the main body 20 face each other within the clearance and do not abut against the surface of either the female mold or the male mold.

[0078] Subsequently, resin material is filled through one or more gates formed in the injection molding die, and injection molding is performed. This forms a resin skeleton 30 integrated with the main body 20. The injection molding apparatus, including the die, can be appropriately designed within the scope of known technology. The gate position may be set at an appropriate location among the lower annular portion 31 or the side column portion 32 of the housing portion 2. An opening or the like may be provided in any panel of the container blank 10, and the gate may be provided in that opening.

[0079] In this embodiment, after forming the resin skeleton 30 integrated with the main body 20 as described above, a rough surface is formed on the inner surface 321a of the side column 32. The rough surface is achieved by applying a predetermined roughening process to the inner surface 321a. An example of the roughening process is a matte finish, such as sandblasting. This completes the manufacturing of the housing 2.

[0080] In the manufacturing method of the housing section 2, the surface of the part of the injection molding die corresponding to the inner surface 321a of the side column section 32 may be pre-treated with surface processing such as sandblasting or texturing. In this case, by forming the resin skeleton section 30 integrated with the main body section 20 using the injection molding die, a rough surface is formed on the inner surface 321a of the side column section 32. Therefore, it is not necessary to roughen the inner surface 321a of the side column section 32 again after forming the resin skeleton section 30 integrated with the main body section 20. If the inner surface 312a is roughened at the stage of injection molding, the manufacturing of the housing section 2 is simplified and the manufacturing cost of the housing section 2 can be reduced.

[0081] [lid] The lid 3 is attached to the top of the storage section 2 and is a member that closes the storage section 2. The lid 3 is attached to the upper annular section 33. In the configuration in which a threaded portion 37 is formed on the upper annular section 33, the lid 3 has a threaded portion on its inner surface that screws into the threaded portion 37. The material of the lid 3 is not limited, but may be a plastic such as polyolefin or polyester, or it may be paper. The lid 3 may be a plastic lid 3 made of polyolefin or polyester, or it may be a paper lid 3 in which the proportion of paper in the weight ratio of the lid 3 is 50% or more.

[0082] The storage section 2 of the container 1 is formed by integrating the main body 20 with the resin skeleton 30. The main body 20 is formed from a container blank 10 containing a predetermined amount of paper. Because the container blank 10 contains a paper layer, the amount of resin contained in the storage section 2 is small compared to the size (capacity) of the storage section 2. Therefore, the storage section 2 and the container 1 equipped with it contribute to reducing the environmental burden. In particular, when the paper weight W1 (g) contained in the storage section 2 is greater than the resin weight W2 (g) (W2 > W1), the reduction in environmental burden is further enhanced. When the paper weight W1 (g) is greater than the resin weight W2 (g), the storage section 2 is a paper product to which a paper mark can be applied.

[0083] The resin skeleton 30 of the storage section 2 is made of a resin with a parallel light transmittance Tb of 18% or more, and the resin skeleton 30 has a liquid level confirmation area 321. Therefore, even if the storage section 2 has a paper layer, the user of the container 1 can check the liquid level of the liquid contents (liquid) from the liquid level confirmation area 321.

[0084] If the inner surface 321a of the liquid level confirmation area 321 is rough, a difference in parallel light transmittance Tb (or haze value) occurs between the part in contact with the liquid contents and the part that is not in contact, due to the relationship of refractive indices. As a result, the contrast between the part in contact with the liquid contents and the part that is not in contact with the liquid contents in the liquid level confirmation area 321 increases, making it easier to confirm the liquid level. For example, on the inner surface 321a of the liquid level confirmation area 321, the part that is not in contact with the liquid becomes white, while the part that is in contact with the liquid becomes nearly colorless and transparent, making it easier to see the position of the liquid level.

[0085] In a configuration where the absolute difference in the haze value of the liquid level confirmation area 321 between when the inner surface 321a is wet with water and when it is not wet with water is 10.0% or more, a better contrast can be secured between the part of the liquid level confirmation area 321 that is in contact with the liquid contents and the part that is not in contact with the liquid contents. As a result, the liquid level becomes easier to confirm.

[0086] Since the main body 20 has a paper layer, no external light enters the storage section 2 from the main body 20. If no light enters the container 1 at all when the lid 3 is attached to the storage section 2, the liquid level cannot be seen. In contrast, the resin that makes up the side column 32 is a resin with a parallel light transmittance Tb (%) of 18% or more. Therefore, when the lid 3 is attached, light enters the container 1 from the side column 32. As a result, the liquid level can be seen even in the container 1 with the lid 3 attached to the storage section 2.

[0087] Thus, since the side column section 32 is the part into which ambient light enters the container 1, the amount of light taken into the container 1 is affected by the width L2 of the side column section 32 and the number of side column sections 32 (n). When the length L3 is expressed as the product of the number of side column sections 32 and the width L2 of the side column sections 32, in a configuration where the ratio R (=L3 / L1) of L3 (mm) to the total circumference L1 (mm) of the storage section 2 is 1% or more, ambient light is easily taken into the container 1 from the side column section 32 even when the lid 3 is attached to the storage section 2. Therefore, visibility of the liquid level is improved. From the viewpoint of taking in more ambient light into the container 1, a ratio R of 5% or more is preferable. As the ratio R increases, the amount of resin in the storage section 2 increases. Therefore, from the viewpoint of reducing environmental impact, the ratio R is preferably less than 25%, preferably 20% or less, and preferably 15% or less.

[0088] [Example of experiment] Next, we will explain Experimental Examples 1 to 19. In the following explanations of Experimental Examples 1 to 19, for the sake of clarity, elements corresponding to each element in the explanation of Container 1 will be assigned the same symbols as in the explanation of Container 1, and redundant explanations will be omitted.

[0089] [Processed paper sheets] A first processed paper sheet, a second processed paper sheet, and a third processed paper sheet were prepared as processed paper sheets for forming container blanks 10.

[0090] <First processed paper sheet> Basis weight: 310 g / m² 2A double-sided coated paper was prepared by extruding polypropylene (PP) to a thickness of 20 μm onto the double-sided coated paper, thereby forming a PP coating layer (hereinafter referred to as the "PP coating layer") on one side.

[0091] A first laminated film was obtained by dry laminating a stretched film (transparent vapor-deposited film: GL-PET manufactured by TOPPAN Corporation (thickness: 12 μm)) and a 60 μm thick unstretched polypropylene (CPP) film (manufactured by Futamura Chemical Co., Ltd.) using a two-component curing urethane adhesive (hereinafter referred to as "first adhesive").

[0092] A first processed paper sheet was obtained by sand-laminating a double-sided coated paper with a PP coating layer and a first laminated film with PE. When sand-laminating the double-sided coated paper and the first laminated film, the double-sided coated paper and the first laminated film were arranged so that the PP coating layer and the CPP film were located on the outside.

[0093] The layer structure of the first processed paper sheet was as follows: PP coating layer / Double-sided coated paper / PE layer / Stretched film / First adhesive / CPP film

[0094] <Second processed paper sheet> Basis weight: 310 g / m² 2 A double-sided coated paper was prepared by extruding low-density polyethylene (LDPE) to a thickness of 20 μm onto the double-sided coated paper, thereby forming an LDPE coating layer (hereinafter referred to as the "LDPE coating layer") on one side. The double-sided coated paper was the same as in the case of the first processed paper sheet.

[0095] A second laminated film was obtained by dry laminating a stretched film (transparent vapor-deposited film: GL-PET (thickness: 12 μm) manufactured by TOPPAN Corporation) and a 60 μm thick linear low-density polyethylene (LLDPE) film (SE620A manufactured by Tamapoly Corporation) using the first adhesive used for the first processed paper sheet. The stretched film was the same as that used for the first processed paper sheet.

[0096] A second processed paper sheet was obtained by sand-laminating a double-sided coated paper with an LDPE coating layer and a second laminated film with PE. When sand-laminating the double-sided coated paper and the second laminated film, the double-sided coated paper and the second laminated film were positioned so that the LDPE coating layer and the LLDPE film were on the outside. The PE used for sand-lamination was the same as that used for the first processed paper sheet.

[0097] The layer structure of the second processed paper sheet was as follows: LDPE coating layer / double-sided coated paper / PE layer / stretched film / first adhesive / LLDPE film

[0098] <Third-generation processed paper sheet> Basis weight: 310 g / m² 2 A 20 μm thick amorphous polyethylene terephthalate (A-PET) film (HS-PET, manufactured by Nissei Chemical Co., Ltd.) was wet-laminated to one side of the double-sided coated paper. A water-soluble adhesive (hereinafter referred to as "second adhesive") was used for wet lamination. The double-sided coated paper was the same as in the case of the first processed paper sheet.

[0099] A third laminated film was obtained by dry laminating a stretched film (transparent vapor-deposited film: GL-PET manufactured by TOPPAN Corporation (thickness: 12 μm)) and a 60 μm thick A-PET film (HS-PET manufactured by Nissei Chemical Co., Ltd.) using a first adhesive. The stretched film was the same as that used in the first processed paper sheet.

[0100] A third processed paper sheet was obtained by sand-laminating a double-sided coated paper with an A-PET film and a third laminated film with PE. When sand-laminating the double-sided coated paper and the third laminated film, the double-sided coated paper and the third laminated film were positioned so that the A-PET film laminated to the double-sided coated paper and the stretched film were on the outside. The PE used for sand-lamination was the same as that used for the first processed paper sheet.

[0101] The layer structure of the third processed paper sheet was as follows: A-PET film / Second adhesive / Double-sided coated paper / PE layer / Stretched film / First adhesive / A-PET film

[0102] <Experimental Example 1> (1) Storage area In Experimental Example 1, a housing 2 having a main body 20 and a resin skeleton 30 was prepared. As shown in Figure 6, the housing 2 of Experimental Example 1 had a rectangular parallelepiped shape, and the upper opening (and bottom surface 21) was square. The size of the cross-section of the main body 20 of the housing 2 of Experimental Example 1, perpendicular to the height direction, was constant in the height direction.

[0103] In Experimental Example 1, the length of one side of the base 21 in the storage section 2 was 70 mm, and the height was 100 mm. The total circumference L1 of the storage section 2 in Experimental Example 1 was 280 mm.

[0104] The resin frame 30 in Experimental Example 1 had two side column sections 32; in other words, the main body 20 in Experimental Example 1 had two slits 23. The width L2 (slit width) of the two side column sections 32 was the same, 7.0 mm. Therefore, the ratio R(L3 / L1) in Experimental Example 1 was 5.0%.

[0105] In Experimental Example 1, the inner surface 321a of the side column 32 was a pear-skin (rough surface), and the entire side column 32 was the liquid level confirmation area 321.

[0106] The material of the resin skeleton 30 in the housing section 2 of Experimental Example 1 was PP. In Experimental Example 1, "Novatec PP MX03ES" manufactured by Nippon Polypropylene Co., Ltd. was used as the PP. The PP (Novatec PP MX03ES, manufactured by Nippon Polypropylene Co., Ltd.) used in Experimental Example 1 will be referred to as "Resin No. 1".

[0107] The housing section 2 of Experimental Example 1 was manufactured as follows: A first processed paper sheet was decorated by offset printing, and a container blank 10 was obtained by die-cutting the decorated first processed paper sheet. The container blank 10 had a bottom panel 11, a side panel 12A, and a side panel 12B. The bottom panel 11, the side panel 12A, and the side panel 12B had shapes and sizes corresponding to the main body 20 of Experimental Example 1.

[0108] Next, the container blank 10 was bent to form the main body 20, and then the resin skeleton 30, which was integrated with the main body 20, was formed by injection molding. The inner surface 321a of the side column 32 was given a textured finish to obtain the storage section 2.

[0109] The textured surface treatment (roughening process) used to achieve the desired roughness of the inner surface 321a of the side column portion 32 in Experimental Example 1 is referred to as the "first textured surface treatment."

[0110] (2) Paper mark The paper weight W1 (g) in the storage section 2 was calculated from the size of the container blank 10 used in Experimental Example 1 and the basis weight of the double-sided coated paper used. The weight of the storage section 2 was measured, and the weight obtained by subtracting the paper weight W1 from the weight of the storage section 2 was calculated as the resin weight W2 (g) contained in the storage section 2.

[0111] In Experimental Example 1, the paper weight W1 (g) and resin weight W2 (g) were 8.25g and 3.36g, respectively, as shown in Figure 8. Therefore, it was possible to mark the storage section 2 in Experimental Example 1 with paper.

[0112] (3) Evaluation of the characteristics of the side column section The characteristics of the side column section 32 of Experimental Example 1 were evaluated using a sample sheet corresponding to the side column section 32 (hereinafter referred to as "Sample Sheet 1"). Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for Sample Sheet 1, which is made of a first resin and has a first textured finish applied to the surface corresponding to the inner surface 321a of the side column section 32. The measurements were performed using a BYK-Gardner Haze-Guard Plus haze meter manufactured by BYK. The haze value was measured in accordance with "JIS K 7136:2000 Plastics - Method for determining haze of transparent materials". The total light transmittance Ta (%) was measured in accordance with "JIS K 7361-1:1997 Plastics - Test method for total light transmittance of transparent materials - Part 1: Single beam method".

[0113] The measurement results are shown in Figure 8. Figure 8 also shows the parallel light transmittance Tb (%) calculated based on equation (1), the haze value α (%) when the material is not wet, and the difference (α - β) between the haze value β (%) when the material is wet. Figure 8 also shows the parallel light transmittance Tb (%), the haze value α (%), and the haze value β (%) when the material is wet for other experimental examples described later.

[0114] (4) Evaluation of liquid level visibility As shown in Figure 7, a box 60 with an open top was prepared. The box 60 is a model of the storage section 2 prepared for liquid level visibility evaluation. The external shape of the box 60 is the same as that of the storage section 2, and the box 60 was made using a first processed paper sheet. A pair of opposing side walls 61 and 62 of the box 60 had slits 63 extending in the height direction. The width L2a of the slits 63 was the same as the width L2. The total circumference L1a of the box 60 was also the same as that of the storage section 2. The length L3a of the box 60, which corresponds to the length L3 in the storage section 2, was the same as the length L3.

[0115] The slit 63 was blocked with the first sample sheet prepared in "(3) Characterization of the side column section," and water was poured into the box 60 so that the liquid level was located at the position of the slit 63. Then, the top of the box 60 was closed with a lid. In this state, five monitors evaluated whether the liquid level was visible through the first sample sheet using the following five-point scale. 5 points: The liquid level is clearly visible. 4 points: The liquid level is clearly visible. 3 points: The liquid level is visible. Points 2: The liquid level is faintly visible. Point 1: The liquid level is completely invisible.

[0116] Based on the total scores from the evaluations of the five monitors, the following three-level evaluation was conducted, and the results were adopted as the evaluation results for the liquid level visibility of the storage compartment 2. Grade A: The total score is 20 or higher. Grade B: The total score is 15 or higher, and less than 10. Grade C: The total is less than 14.

[0117] In the evaluation of liquid level visibility in container 2 of Experimental Example 1, the total score was 21. Therefore, the liquid level visibility evaluation in Experimental Example 1 was an A rating, as shown in Figure 8.

[0118] (Experimental Examples 2-4) (1) Storage area For experimental examples 2 to 4, the same housing section 2 as in experimental example 1 was prepared, except that the textured surface (roughened surface) of the inner surface 321a of the side column section 32 was different. The processed paper sheets used in Experimental Examples 2-4 were the same as the first processed paper sheets used in Experimental Example 1. In experimental examples 2-4, the material of the resin skeleton 30 was the first resin. The ratio R in housing section 2 in experimental examples 2-4 was the same as in experimental example 1.

[0119] The roughness of the inner surface 321a of the side column 32 in Experimental Examples 2-4 was rougher than in Experimental Example 1. The inner surface 321a of the side column 32 in Experimental Examples 2-4 was rougher in Experimental Example 3 than in Experimental Example 2, and rougher in Experimental Example 4 than in Experimental Example 3.

[0120] In Experimental Example 2, after forming the resin skeleton 30 by injection molding, the inner surface 321a of the side column 32 was given a textured finish so that the texture of the inner surface 321a of the side column 32 was rougher than in Experimental Example 1. The textured finish used to achieve the desired roughness of the inner surface 321a of the side column 32 in Experimental Example 2 is referred to as the "second textured finish."

[0121] In Experimental Example 3, after forming the resin skeleton 30 by injection molding, the inner surface 321a of the side column 32 was given a textured finish so that the texture of the inner surface 321a of the side column 32 was rougher than in Experimental Example 2. The textured finish used to achieve the desired roughness of the inner surface 321a of the side column 32 in Experimental Example 3 is referred to as the "third textured finish."

[0122] In Experimental Example 4, after forming the resin skeleton 30 by injection molding, the inner surface 321a of the side column 32 was given a textured finish so that the texture of the inner surface 321a of the side column 32 was rougher than in Experimental Example 3. The textured finish used to achieve the desired roughness of the inner surface 321a of the side column portion 32 in Experimental Example 4 is referred to as the "fourth textured finish."

[0123] (2) Paper mark The paper weight W1 and resin weight W2 in storage section 2 of Experimental Examples 2-4 were the same as in Experimental Example 1, as shown in Figure 8. Storage section 2 in Experimental Examples 2-4 was also a storage section to which a paper mark could be applied.

[0124] (3) Evaluation of the characteristics of the side column section The characteristics of the side column sections 32 in Experimental Examples 2 to 4 were evaluated in the same manner as in Experimental Example 1, using sample sheets corresponding to each of the side column sections 32 in Experimental Examples 2 to 4 (hereinafter referred to as "Sample Sheets 2 to 4"). Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for Sample Sheets 2 to 4.

[0125] The second sample sheet corresponding to the side column portion 32 of Experimental Example 2 was made of the first resin and had a second textured finish applied to the surface corresponding to the inner surface 321a. The third sample sheet corresponding to the side column portion 32 of Experimental Example 3 was made of the first resin and had a third textured finish applied to the surface corresponding to the inner surface 321a. The fourth sample sheet corresponding to the side column portion 32 of Experimental Example 4 was made of the first resin and had a fourth textured finish applied to the surface corresponding to the inner surface 321a.

[0126] The measurement results are shown in Figure 8.

[0127] (4) Evaluation of liquid level visibility Except for using the second to fourth sample sheets as sample sheets, the liquid level visibility was evaluated in the same manner as in Experimental Example 1. The evaluation criteria were the same as in Experimental Example 1.

[0128] In the liquid level visibility evaluation of Experimental Example 2, the total score was 22. Therefore, the liquid level visibility evaluation in Experimental Example 2 was rated A, as shown in Figure 8. In the liquid level visibility evaluation of Experimental Example 3, the total score was 24. Therefore, the liquid level visibility evaluation in Experimental Example 3 was rated A, as shown in Figure 8. In the liquid level visibility evaluation of Experimental Example 4, the total score was 23. Therefore, the liquid level visibility evaluation in Experimental Example 4 was rated A, as shown in Figure 8.

[0129] (Experimental Example 5) (1) Storage area For Experimental Example 5, a housing section 2 was prepared in the same way as in Experimental Example 1, except that PP, which is different from the material used in Experimental Example 1, was used for the resin skeleton section 30. The processed paper sheet used in Experimental Example 5 was the same first processed paper sheet as in Experimental Example 1. The ratio R in housing section 2 of Experimental Example 5 was the same as in Experimental Example 1. In Experimental Example 5, the inner surface 321a of the side column 32 was a pear-skin surface that had undergone the first pear-skin processing.

[0130] In Experimental Example 5, "Prime PolyPro J226ED" manufactured by Prime Polymer Co., Ltd. was used as the PP material. The PP (Prime PolyPro J226ED, manufactured by Prime Polymer Co., Ltd.) used in Experimental Example 5 is referred to as the "second resin."

[0131] (2) Paper mark As shown in Figure 8, the paper weight W1 and resin weight W2 in the storage compartment 2 of Experimental Example 5 were the same as in Experimental Example 1. Paper marks could be applied to the storage compartment 2 of Experimental Example 5.

[0132] (3) Evaluation of the characteristics of the side column section The characteristics of the side column section 32 in Experimental Example 5 were evaluated in the same manner as in Experimental Example 1, using the fifth sample sheet corresponding to the side column section 32 in Experimental Example 5. Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for the fifth sample sheet.

[0133] The fifth sample sheet was made of the second resin and had the first textured finish applied to the surface corresponding to the inner surface 321a.

[0134] The measurement results are shown in Figure 8.

[0135] (4) Evaluation of liquid level visibility Except for using the fifth sample sheet as the sample sheet, the liquid level visibility was evaluated in the same manner as in Experimental Example 1. The evaluation criteria were the same as in Experimental Example 1.

[0136] In the liquid level visibility evaluation for Experimental Example 5, the total score was 20. The liquid level visibility evaluation in Experimental Example 5 was rated A, as shown in Figure 8.

[0137] (Experimental Examples 6-8) (1) Storage area For experimental examples 6-8, the same housing section 2 as in experimental example 5 was prepared, except that the inner surface of the side column section 32 had a different textured (roughened) finish. The processed paper sheets used in Experimental Examples 6-8 were the same first processed paper sheets as in Experimental Example 5. The material of the resin skeleton 30 in experimental examples 6-8 was the second resin. The ratio R in housing section 2 in experimental examples 6-8 was the same as in experimental example 5.

[0138] (2) Paper mark The paper weight W1 and resin weight W2 in the storage compartment 2 of Experimental Examples 6-8 were the same as in Experimental Example 5, as shown in Figure 8. Paper marks could be applied to the storage compartment 2 of Experimental Examples 6-8.

[0139] (3) Evaluation of the characteristics of the side column section The characteristics of the side column sections 32 in Experimental Examples 6-8 were evaluated using the 6th-8th sample sheets corresponding to the side column sections 32 in Experimental Examples 6-8, in the same manner as in Experimental Example 1. Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for the 6th-8th sample sheets.

[0140] The sixth sample sheet corresponding to the side column portion 32 of Experimental Example 6 was made of the second resin and had a second textured finish applied to the surface corresponding to the inner surface 321a. The seventh sample sheet corresponding to the side column portion 32 of Experimental Example 7 was made of the second resin and had a third textured finish applied to the surface corresponding to the inner surface 321a. The eighth sample sheet corresponding to the side column portion 32 of experimental example 8 was made of the second resin and had a fourth textured finish applied to the surface corresponding to the inner surface 321a.

[0141] The measurement results are shown in Figure 8.

[0142] (4) Evaluation of liquid level visibility Except for using sample sheets 6 through 8 as sample sheets, the liquid level visibility was evaluated in the same manner as in Experimental Example 1. The evaluation criteria were the same as in Experimental Example 1.

[0143] In the liquid level visibility evaluation of Experimental Example 6, the total score was 20. The liquid level visibility evaluation in Experimental Example 6 was rated A, as shown in Figure 8. In the liquid level visibility evaluation for Experiment Example 7, the total score was 22. The liquid level visibility evaluation in Experiment Example 7 was rated A, as shown in Figure 8. In the liquid level visibility evaluation of Experimental Example 8, the total score was 22. The liquid level visibility evaluation in Experimental Example 8 was rated A, as shown in Figure 8.

[0144] (Experimental Example 9) (1) Storage area For Experimental Example 9, a housing section 2 was prepared in the same manner as in Experimental Example 1, except that the width L2 (slit width) of the side column section 32 was set to 28.0 mm and the textured surface (rough surface) of the inner surface 321a of the side column section 32 was different. The width L2 was adjusted by changing the size of the side panels 12A and 12B of the container blank 10. The processed paper sheet used in Experimental Example 9 was the first processed paper sheet. In Experimental Example 9, the material of the resin skeleton 30 was the first resin. In Experimental Example 9, the ratio R was 20.0%. In Experimental Example 9, the inner surface 321a of the side column 32 was a pear-skin surface that had undergone a fourth pear-skin finish.

[0145] (2) Paper mark The paper weight W1 and resin weight W2 in the storage compartment 2 of Experimental Example 9 were obtained in the same manner as in Experimental Example 1. The paper weight W1 and resin weight W2 were 6.94 g and 6.06 g, respectively. Paper marks could be applied to the storage compartment 2 of Experimental Example 9.

[0146] (3) Evaluation of the characteristics of the side column section The characteristics of the side column section 32 of Experimental Example 9 were evaluated using the 9th sample sheet corresponding to the side column section 32 of Experimental Example 9, in the same manner as in Experimental Example 1. Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for the 9th sample sheet.

[0147] The ninth sample sheet was made of the first resin and had a fourth textured finish applied to the surface corresponding to the inner surface 321a.

[0148] The measurement results are shown in Figure 8.

[0149] (4) Evaluation of liquid level visibility Except for using the 9th sample sheet as the sample sheet and using a box 60 with a ratio R of 20.0% corresponding to the containment section 2 of Experimental Example 9, the liquid level visibility was evaluated in the same manner as in Experimental Example 1. The evaluation criteria were the same as in Experimental Example 1.

[0150] The box 60 used in Experimental Example 9 was the same as the box used in Experimental Example 1, except that the width of the slit 63 was 28.0 mm.

[0151] In the liquid level visibility evaluation for Experimental Example 9, the total score was 24. The liquid level visibility evaluation in Experimental Example 9 was rated A, as shown in Figure 8.

[0152] (Experimental Example 10) (1) Storage area For Experimental Example 10, a housing section 2 was manufactured that was the same as in Experimental Example 1, except that the width L2 (slit width) of the side column section 32 was set to 1.4 mm and the textured surface (roughened surface) of the inner surface 321a of the side column section 32 was different. The width L2 was adjusted by changing the size of the side panels 12A and 12B of the container blank 10. The processed paper sheet used in Experimental Example 10 was the first processed paper sheet. In Experimental Example 10, the material of the resin skeleton 30 was the first resin. In Experimental Example 10, the ratio R was 1.0%. In experimental example 10, the inner surface 321a of the side column 32 was a pear-skin surface that had undergone a fourth pear-skin finish.

[0153] (2) Paper mark The paper weight W1 and resin weight W2 in the storage compartment 2 of Experimental Example 10 were obtained in the same manner as in Experimental Example 1. The paper weight W1 and resin weight W2 were 8.59 g and 2.64 g, respectively. Paper marks could be applied to the storage compartment 2 of Experimental Example 10.

[0154] (3) Evaluation of the characteristics of the side column section The characteristics of the side column section 32 of Experimental Example 10 were evaluated using the 10th sample sheet corresponding to the side column section 32 of Experimental Example 10, in the same manner as in Experimental Example 1. Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for the 10th sample sheet.

[0155] The 10th sample sheet was made of the first resin and had a fourth textured finish applied to the surface corresponding to the inner surface 321a.

[0156] The measurement results are shown in Figure 8.

[0157] (4) Evaluation of liquid level visibility Except for using the 10th sample sheet as the sample sheet and using a box 60 with a ratio R of 1.0% corresponding to the containment section 2 of Experimental Example 10, the liquid level visibility was evaluated in the same manner as in Experimental Example 1. The evaluation criteria were the same as in Experimental Example 1.

[0158] The box 60 used in Experimental Example 10 was the same as the box used in Experimental Example 1, except that the width of the slit 63 was 1.4 mm.

[0159] In the liquid level visibility evaluation for Experimental Example 10, the total score was 18. The liquid level visibility evaluation for Experimental Example 10 was a rating of B, as shown in Figure 8.

[0160] (Experimental Example 11) (1) Storage area For Experimental Example 11, the same type of housing 2 was prepared as in Experimental Example 1, except that the container blank 10 was formed from the second processed paper sheet and PE was used as the material for the resin skeleton 30. The ratio R in Experimental Example 11 was the same as in Experimental Example 1. The inner surface 321a of the side column 32 in experimental example 11 was a pear-skin surface that had been subjected to the first pear-skin finish.

[0161] For the resin skeleton part 30 in Experimental Example 11, the material (PE) used was "Petrocene 360" manufactured by Tosoh Corporation. The PE (Petrocene 360, manufactured by Tosoh Corporation) used in Experimental Example 11 is referred to as the "third resin."

[0162] (2) Paper mark The paper weight W1 and resin weight W2 in the storage compartment 2 of Experimental Example 11 were obtained in the same manner as in Experimental Example 1. The paper weight W1 and resin weight W2 were 8.25 g and 3.42 g, respectively. Paper marks could be applied to the storage compartment 2 of Experimental Example 11.

[0163] (3) Evaluation of the characteristics of the side column section The characteristics of the side column section 32 of Experimental Example 11 were evaluated using the 11th sample sheet corresponding to the side column section 32 of Experimental Example 11, in the same manner as in Experimental Example 1. Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for the 11th sample sheet.

[0164] The 11th sample sheet was made of the first resin and had a first textured finish applied to the surface corresponding to the inner surface 321a.

[0165] The measurement results are shown in Figure 8.

[0166] (4) Evaluation of liquid level visibility Except for using the 11th sample sheet as the sample sheet and using the 2nd processed paper sheet to create the box 60, the liquid level visibility was evaluated in the same manner as in Experimental Example 1. The evaluation criteria were the same as in Experimental Example 1.

[0167] In the liquid level visibility evaluation of Experimental Example 11, the total score was 18. The liquid level visibility evaluation in Experimental Example 11 was a rating of B, as shown in Figure 8.

[0168] (Experimental Example 12) (1) Storage area For Experimental Example 12, the same storage section 2 was prepared as in Experimental Example 11, except that the container blank 10 was formed from the second processed paper sheet and the textured (roughened) surface of the inner surface 321a of the side column section 32 was different. The processed paper sheet used in Experimental Example 12 was the second processed paper sheet. In Experimental Example 12, the material of the resin skeleton 30 was the third resin. The ratio R in Experimental Example 12 was the same as in Experimental Example 11. In Experimental Example 12, the inner surface 321a of the side column 32 was a pear-skin surface that had undergone a fourth type of pear-skin processing.

[0169] (2) Paper mark The paper weight W1 and resin weight W2 in the storage compartment 2 of Experimental Example 10 were obtained in the same manner as in Experimental Example 1. The paper weight W1 and resin weight W2 were 8.26 g and 3.42 g, respectively. Paper marks could be applied to the storage compartment 2 of Experimental Example 12.

[0170] (3) Evaluation of the characteristics of the side column section The characteristics of the side column section 32 of Experimental Example 12 were evaluated in the same manner as in Experimental Example 1, using the 12th sample sheet corresponding to the side column section 32 of Experimental Example 12. Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for the 12th sample sheet.

[0171] The 12th sample sheet was made of the third resin and had a fourth textured finish applied to the surface corresponding to the inner surface 321a.

[0172] The measurement results are shown in Figure 8.

[0173] (4) Evaluation of liquid level visibility Except for using the 12th sample sheet as the sample sheet and using the second processed paper sheet to create the box 60, the liquid level visibility was evaluated in the same manner as in Experimental Example 1. The evaluation criteria were the same as in Experimental Example 1.

[0174] In the liquid level visibility evaluation of Experimental Example 12, the total score was 20. The liquid level visibility evaluation in Experimental Example 12 was a rating of B, as shown in Figure 8.

[0175] (Experimental Example 13) (1) Storage area In Experimental Example 13, the same type of housing 2 was manufactured as in Experimental Example 1, except that the container blank 10 was formed from a third processed paper sheet, PET was used as the material for the resin skeleton 30, and the textured surface (rough surface) of the inner surface 321a of the side column 32 was different. The ratio R in Experimental Example 13 was the same as in Experimental Example 4. The inner surface 321a of the side column 32 in experimental example 13 was a pear-skin surface that had undergone a fourth type of pear-skin processing.

[0176] For the resin skeleton 30 material (PET) in Experimental Example 13, "Eastman Copolyester GN001" manufactured by Eastman Chemical Company was used. The PET (Eastman Chemical Company's "Eastian Copolyester GN001") used in Experimental Example 13 is referred to as the "fourth resin."

[0177] (2) Paper mark The paper weight W1 and resin weight W2 in the storage compartment 2 of Experimental Example 13 were obtained in the same manner as in Experimental Example 1. The paper weight W1 and resin weight W2 were 8.25 g and 4.71 g, respectively. Paper marks could be applied to the storage compartment 2 of Experimental Example 13.

[0178] (3) Evaluation of the characteristics of the side column section The characteristics of the side column section 32 of Experimental Example 13 were evaluated in the same manner as in Experimental Example 1, using the 13th sample sheet corresponding to the side column section 32 of Experimental Example 13. Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for the 13th sample sheet.

[0179] The 13th sample sheet was made of the fourth resin and had a fourth textured finish applied to the surface corresponding to the inner surface 321a.

[0180] The measurement results are shown in Figure 8.

[0181] (4) Evaluation of liquid level visibility Except for using the 13th sample sheet as the sample sheet and using the 3rd processed paper sheet to create the box 60, the liquid level visibility was evaluated in the same manner as in Experimental Example 1. The evaluation criteria were the same as in Experimental Example 1.

[0182] In the liquid level visibility evaluation of Experimental Example 13, the total score was 19. The liquid level visibility evaluation in Experimental Example 13 was a rating of B, as shown in Figure 8.

[0183] (Experimental Example 14) In Experimental Example 14, as shown in Figure 1, a housing section 2 was prepared having a main body section 20 and a resin skeleton section 30, with a circular upper opening (and bottom surface 21). The size of the cross-section of the main body section 20 of the housing section 2 in Experimental Example 14, perpendicular to the height direction, was constant in the height direction.

[0184] In Experimental Example 14, the diameter of the bottom surface 21 of the storage section 2 was 55 mm, and the height was 42.5 mm. The total circumference L1 of the storage section 2 in Experimental Example 14 was 172.8 mm.

[0185] The material of the resin skeleton 30 in Experimental Example 14 was the first resin. The resin skeleton 30 in Experimental Example 14 had two side column sections 32. In other words, the main body 20 in Experimental Example 14 had two slits 23. The width L2 (slit width) of the two side column sections 32 in Experimental Example 14 was the same, 4.3 mm. The ratio R((2 × L2) / L1) in Experimental Example 14 was 5.0%.

[0186] In Experimental Example 14, the inner surface 321a of the side column 32 was a pear-skin surface with a first pear-skin finish, and the entire side column 32 was the liquid level confirmation area 321.

[0187] The storage section 2 in Experimental Example 14 was manufactured in the same manner as in Experimental Example 1, except that the container blank 10 using the first processed paper sheet had a shape and size corresponding to the storage section 2 (specifically, the main body 20) of Experimental Example 14.

[0188] (2) Paper mark The paper weight W1 and resin weight W2 in the storage compartment 2 of Experimental Example 14 were obtained in the same manner as in Experimental Example 1. The paper weight W1 and resin weight W2 were 2.57 g and 2.35 g, respectively. Paper marks could be applied to the storage compartment 2 of Experimental Example 14.

[0189] (3) Evaluation of the characteristics of the side column section The characteristics of the side column section 32 of Experimental Example 14 were evaluated in the same manner as in Experimental Example 1, using the 14th sample sheet corresponding to the side column section 32 of Experimental Example 14. Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for the 14th sample sheet.

[0190] The 14th sample sheet was made of the first resin and had a first textured finish applied to the surface corresponding to the inner surface 321a.

[0191] The measurement results are shown in Figure 8.

[0192] (4) Evaluation of liquid level visibility Except for using the 14th sample sheet as the sample sheet and using a box 60 with an external shape corresponding to the containment section 2 of Experimental Example 14 and a ratio R of 5.0%, the liquid level visibility was evaluated in the same manner as in Experimental Example 1. The evaluation criteria were the same as in Experimental Example 1.

[0193] The box 60 used in Experimental Example 14 had the same cylindrical outer shape as the storage section 2 in Experimental Example 14, and the total circumference of the container body and the slit width were the same as the total circumference L1 and width L2 of the storage section 2 in Experimental Example 14.

[0194] In the liquid level visibility evaluation of Experimental Example 14, the total score was 21. The liquid level visibility evaluation in Experimental Example 14 was rated A, as shown in Figure 8.

[0195] (Experimental Example 15) (1) Storage area For Experimental Example 15, a housing section 2 similar to that in Experimental Example 1 was prepared, except that the inner surface 321a of the side column section 32 was not textured. In Experimental Example 15, the inner surface of the side column section 32 was flat (mirror-like).

[0196] The processed paper sheet used in Experimental Example 15 was the first processed paper sheet. In Experimental Example 15, the material of the resin skeleton 30 was the first resin. The ratio R in housing section 2 of experimental example 15 was the same as in experimental example 1.

[0197] (2) Paper mark The paper weight W1 and resin weight W2 in the storage compartment 2 of Experimental Example 15 were the same as in Experimental Example 1. Paper marks could be applied to the storage compartment 2 of Experimental Example 15.

[0198] (3) Evaluation of the characteristics of the side column section The characteristics of the side column section 32 of Experimental Example 15 were evaluated in the same manner as in Experimental Example 1, using the 15th sample sheet corresponding to the side column section 32 of Experimental Example 15. Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for the 15th sample sheet.

[0199] The 15th sample sheet was made of the first resin, and the surface corresponding to the inner surface 321a was a flat surface (mirror surface).

[0200] The measurement results are shown in Figure 9.

[0201] (4) Evaluation of liquid level visibility Except for using Sample Sheet No. 15 as the sample sheet, the liquid level visibility was evaluated in the same manner as in Experimental Example 1. The evaluation criteria were the same as in Experimental Example 1.

[0202] In the liquid level visibility evaluation of Experimental Example 15, the total score was 8. The liquid level visibility evaluation in Experimental Example 15 was a rating of C, as shown in Figure 9.

[0203] (Experimental Example 16) (1) Storage area For Experimental Example 16, a housing section 2 was prepared in the same manner as in Experimental Example 15, except that the material used for the resin skeleton section 30 was a second resin. The processed paper sheet used in Experimental Example 16 was the first processed paper sheet. The ratio R in housing section 2 of Experimental Example 16 was the same as in Experimental Example 15 (Experimental Example 1). In experimental example 16, the inner surface 321a of the side column portion 32 was a flat surface (mirror surface).

[0204] (2) Paper mark The paper weight W1 and resin weight W2 in the storage compartment 2 of Experimental Example 16 were the same as in Experimental Example 15 (Experimental Example 1). Paper marks could be applied to the storage compartment 2 of Experimental Example 16.

[0205] (3) Evaluation of the characteristics of the side column section The characteristics of the side column section 32 of Experimental Example 16 were evaluated using the 16th sample sheet corresponding to the side column section 32 of Experimental Example 16, in the same manner as in Experimental Example 15 (Experimental Example 1). Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for the 16th sample sheet.

[0206] The 15th sample sheet was made of the second resin, and its inner surface 321a was a flat surface (mirror surface).

[0207] The measurement results are shown in Figure 9.

[0208] (4) Evaluation of liquid level visibility Except for using Sample Sheet No. 16 as the sample sheet, the liquid level visibility was evaluated in the same manner as in Experimental Example 15 (Experimental Example 1). The evaluation criteria were the same as in Experimental Example 15 (Experimental Example 1).

[0209] In the liquid level visibility evaluation of Experimental Example 16, the total score was 7. The liquid level visibility evaluation in Experimental Example 16 was a rating of C, as shown in Figure 9.

[0210] (Experimental Example 17) (1) Storage area For Experimental Example 17, the same housing section 2 as in Experimental Example 11 was prepared, except that the inner surface 321a of the side column section 32 was not textured. In Experimental Example 17, the inner surface of the side column section 32 was a flat surface (mirror surface).

[0211] The processed paper sheet used in Experimental Example 17 was the second processed paper sheet. In Experimental Example 17, the material of the resin skeleton 30 was the third resin. The ratio R in housing section 2 of experimental example 17 was the same as in experimental example 11.

[0212] (2) Paper mark The paper weight W1 and resin weight W2 in the storage compartment 2 of Experimental Example 17 were obtained in the same manner as in Experimental Example 1. The paper weight W1 and resin weight W2 were 8.25 g and 3.42 g, respectively. Paper marks could be applied to the storage compartment 2 of Experimental Example 17.

[0213] (3) Evaluation of the characteristics of the side column section The characteristics of the side column section 32 of Experimental Example 17 were evaluated using the 17th sample sheet corresponding to the side column section 32 of Experimental Example 17, in the same manner as in Experimental Example 1. Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for the 17th sample sheet.

[0214] Sample sheet No. 17 was made of the third resin, and its inner surface 321a was a flat surface (mirror surface).

[0215] The measurement results are shown in Figure 9.

[0216] (4) Evaluation of liquid level visibility Except for using Sample Sheet No. 17 as the sample sheet, the liquid level visibility was evaluated in the same manner as in Experimental Example 11. The evaluation criteria were the same as in Experimental Example 11 (Experimental Example 1).

[0217] In the liquid level visibility evaluation of Experimental Example 17, the total score was 5. The liquid level visibility evaluation in Experimental Example 17 was a rating of C, as shown in Figure 9.

[0218] (Experimental Example 18) (1) Storage area For Experimental Example 18, the same housing section 2 as in Experimental Example 13 was prepared, except that the inner surface 321a of the side column section 32 was not textured. In Experimental Example 18, the inner surface 321a of the side column section 32 was a flat surface (mirror surface).

[0219] The processed paper sheet used in Experimental Example 18 was the third processed paper sheet. In Experimental Example 18, the material of the resin skeleton 30 was the fourth resin. The ratio R in housing section 2 of experimental example 18 was the same as in experimental example 13.

[0220] (2) Paper mark The paper weight W1 and resin weight W2 in the storage compartment 2 of Experimental Example 18 were obtained in the same manner as in Experimental Example 1. The paper weight W1 and resin weight were 8.25 g and 4.71 g, respectively. Paper marks could be applied to the storage compartment 2 of Experimental Example 18.

[0221] (3) Evaluation of the characteristics of the side column section The characteristics of the side column section 32 of Experimental Example 18 were evaluated in the same manner as in Experimental Example 1, using the 18th sample sheet corresponding to the side column section 32 of Experimental Example 18. Specifically, the haze value α (%), total light transmittance Ta (%), and haze value β (%) when wet were measured for the 18th sample sheet.

[0222] The 18th sample sheet was made of the fourth resin, and the surface corresponding to the inner surface 321a was a flat surface (mirror surface).

[0223] The measurement results are shown in Figure 9.

[0224] (4) Evaluation of liquid level visibility Except for using Sample Sheet No. 17 as the sample sheet, the liquid level visibility was evaluated in the same manner as in Experimental Example 13. The evaluation criteria were the same as in Experimental Example 13 (Experimental Example 1).

[0225] In the liquid level visibility evaluation of Experimental Example 18, the total score was 11. The liquid level visibility evaluation in Experimental Example 18 was a rating of C, as shown in Figure 6.

[0226] (Experimental Example 19) (1) Storage area For Experimental Example 19, a housing section 2 was prepared in the same manner as in Experimental Example 1, except that the width L2 (slit width) of the side column section 32 was set to 35.0 mm. The width L2 was adjusted by changing the size of the side panels 12A and 12B of the container blank 10. The processed paper sheet used in Experimental Example 19 was the first processed paper sheet. In Experimental Example 19, the material of the resin skeleton 30 was the first resin. In Experimental Example 19, the ratio R was 25.0%.

[0227] (2) Paper mark The paper weight W1 and the resin weight W2 in the housing 2 of Experimental Example 19 were obtained in the same manner as in Experimental Example 1. In Experimental Example 19, the paper weight W1 and the resin weight W2 were 6.51 g and 6.96 g, respectively. It was impossible to apply a paper mark to the housing 2 of Experimental Example 19.

[0228] (3) Characteristic evaluation of the side pillar part The characteristics of the side pillar part 32 of Experimental Example 19 were evaluated in the same manner as in the case of Experimental Example 1 using the 19th sample sheet corresponding to the side pillar part 32 of Experimental Example 19. That is, the haze value α (%), the total light transmittance Ta (%), and the haze value β (%) when wet with water of the 19th sample sheet were measured.

[0229] The 19th sample sheet was a sheet made of the first resin and having the first embossing treatment on the surface corresponding to the inner surface 321a.

[0230] The measurement results were as shown in FIG. 9.

[0231] (4) Liquid level visibility evaluation The liquid level visibility was evaluated in the same manner as in the case of Experimental Example 1, except that the 19th sample sheet was used as the sample sheet and the box body 60 having a ratio R of 25.0% according to the housing 2 of Experimental Example 19 was used. The evaluation criteria were the same as in the case of Experimental Example 1.

[0232] The box body 60 corresponding to the housing 2 of Experimental Example 19 was the same box body as in the case of Experimental Example 1, except that the width of the slit 63 was 35.0 mm.

[0233] In the liquid level visibility evaluation of Experimental Example 19, the total score was 23. The liquid level visibility evaluation in Experimental Example 19 was Evaluation A, as shown in FIG. 8.

[0234] FIG. 8 is a chart showing the results of Experimental Examples 1 to 14. FIG. 9 is a chart showing the results of Experimental Examples 15 to 19. In FIGS. 8 and 9, α, β, Ta, Tb, L1, L2, ratio R, W1 and W2 are as follows. α (%) : haze value when not wet with water β (%) : haze value when wet with water Ta (%) : total light transmittance Tb (%) : parallel light transmittance L1 (mm) : total peripheral length of the housing L2 (mm) : width of the side pillar portion Ratio R: (2 × L2) / L1 W1 (g) : paper weight W2 (g) : resin weight In FIGS. 8 and 9, the evaluation result of "visibility" is the evaluation result of "liquid surface visibility".

[0235] In the housing 2 of Experimental Examples 15 to 18, the inner surface 321a was a flat surface (mirror surface). In Experimental Examples 15 to 18, the absolute value of the difference (α - β) between the haze value α and the haze value β was 0.5 or less. In Experimental Examples 15 to 18, the contrast at the position of the liquid surface was small. In such Experimental Examples 15 to 18, the liquid surface visibility evaluation in Experimental Examples 15 to 18 was Evaluation C.

[0236] On the other hand, the inner surface 321a of Experimental Examples 1 to 14 and Experimental Example 19 was a matte surface. In Experimental Examples 1 to 14 and Experimental Example 9, the absolute value of the difference (α - β) between the haze value α and the haze value β was greater than 0.5 and 10 or more. In Experimental Examples 1 to 14 and Experimental Example 19, the contrast at the position of the liquid surface was large. In Experimental Examples 1 to 14 and Experimental Example 19, the liquid surface was easy to visually recognize, and the liquid surface visibility was Evaluation A or Evaluation B.

[0237] Therefore, it was confirmed that the liquid surface visibility was improved by the inner surface 321a being a rough surface.

[0238] From the results of Experimental Examples 1-14 and Experimental Example 19, it can be understood that the liquid level is easily visible when the ratio R is 1% or higher. In particular, from the comparison of Experimental Examples 4, 9, and 10, which have the same configuration except for the difference in width L2, and the comparison of Experimental Example 1 and Experimental Example 19, it can be understood that the liquid level visibility improves as the ratio R increases. However, when the ratio R is 25.0% or higher, the weight of the resin in the containment section 2 becomes large, making it impossible to apply a paper mark. Therefore, from the viewpoint of reducing environmental impact, it is preferable that the ratio R is less than 25.0%.

[0239] Although embodiments and experimental examples of the present invention have been described above, the present invention is not limited to the embodiments and experimental examples illustrated above, and is intended to include the scope indicated by the claims, as well as all modifications within the meaning and scope equivalent to the claims.

[0240] The number of side panels on a container blank is not limited to two; it may have one. For example, either of the two example side panels 12A and 12B may be omitted. In that case, the container blank will have only one side panel. This single side panel includes a bottom edge that is slightly shorter than the entire circumference of the bottom panel. The number of side panels on a container blank may be three or more.

[0241] The layer structure of the container planks is not limited as long as it includes a paper layer, can be integrated with the resin skeleton, and can contain liquid contents.

[0242] The bottom (bottom panel) and sides (side panels) were connected, but they may be separated. In this case, the main body is formed by integrating them with the resin frame. The bottom (bottom panel) does not need to have a paper layer.

[0243] The width of the side column does not have to be uniform along the direction of extension of the side column. The entire side column does not have to be a liquid level confirmation area.

[0244] For example, a portion of the side column may be a liquid level inspection area, and the width of this liquid level inspection area may be wider than that of other parts. The inner surface of such a liquid level inspection area may be a flat surface (mirror surface). Even if the inner surface of the liquid level inspection area is a flat surface, the wider width of the liquid level inspection area makes it easier to check the liquid level. [Explanation of Symbols]

[0245] 1...Container, 2...Storage section, 3...Lid, 11...Bottom panel, 12A, 12B...Side panels, 10...Container blanks, 20...Main body, 21...Bottom, 22...Side, 23...Slit, 30...Resin frame, 32...Side column, 55...Paper layer.

Claims

1. The top is open and has a compartment for storing liquid contents, A lid attached to the upper part of the storage section, Equipped with, The aforementioned housing section is Resin frame part, A main body portion integrated with the resin frame portion, including the bottom and sides, It has, The parallel light transmittance of the resin forming the resin skeleton is 18% or more. The bottom surface and the side surface include a paper layer. A slit is formed on the aforementioned side surface, extending in a direction intersecting the bottom surface. The resin skeleton portion has a side column portion that closes the slit, At least a portion of the aforementioned side column is a liquid level confirmation area for confirming the liquid level of the liquid contents. container.

2. The inner surface of the liquid level confirmation area is rough. The container according to claim 1.

3. The aforementioned rough surface is a pear-shaped surface. The container according to claim 2.

4. The absolute value of the difference in the haze value of the liquid level inspection area when the inner surface is wet with water and when it is not wet with water is 10.0% or more. The container according to claim 2.

5. The entire side column portion constitutes the liquid level confirmation area. The container according to any one of claims 1 to 4.

6. The main body is a three-dimensional blank made by folding a container blank in a three-dimensional manner. The container blanks mentioned above are The bottom panel corresponding to the bottom surface, It comprises at least one side panel corresponding to the aforementioned side surface and connected to the peripheral edge of the bottom panel, In the aforementioned three-dimensional blank, the side panel is bent relative to the bottom panel. The container according to any one of claims 1 to 4.

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