Sheet and container

Abstract

To enable easy opening, for example, by one hand irrespective of a difference between seal strengths and a pressure from the inside.SOLUTION: A sheet contains at least a core layer containing a resin as a material, wherein the core layer contains polypropylene, and coagulation strength of the core layer is 0.3 kgf / 15 mm or more and 3.0 kgf / 15 mm or less.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a sheet and a container.

Background Art

[0002] Techniques related to a liquid storage container in which a pouring start portion of a seal portion is broken by pressing with a finger to pour out a liquid are described in, for example, Patent Document 1. Patent Document 1 has a container body with a flange portion formed at an opening and a lid body covering the opening, a circumferential seal portion is formed on the flange portion, and a pouring start portion that can be peeled off by pressing with a finger against the container body is formed in a part of the seal portion to pour out a liquid. A liquid storage container is described.

[0003] Furthermore, as an improvement of the above technique, Patent Document 2 describes a container including a container body including a crushable recess and a flange portion extending from the periphery of the recess, and a lid body joined to the container body at a joining region formed on the flange portion. In this container, by forming a weak seal portion in which a plurality of non-joining regions isolated in a part of the circumferential direction of the joining region are arranged, a pouring portion with a desired seal strength is stably formed, and a technique for maintaining the airtightness of the container is described.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technique of opening a container by making the sealing strength of the extraction part weaker than other parts as described above, it is necessary to have a sufficient difference in sealing strength between the extraction part and other parts. Also, if the sealing strength of the extraction part is too weak, there is a possibility that the container may be unintentionally opened during processing such as sterilization during transportation, so the conditions such as the sealing temperature during manufacturing may become strict. Further, since the seal is peeled off by the pressure from the inside, when the viscosity of the content is low, the content may be extracted vigorously and scattered. Furthermore, since pressure must be applied when the concave part is crushed in the extraction part, there are limitations on the container shape and the position of the extraction part.

[0006] Therefore, an object of the present invention is to provide a sheet and a container that enable easy opening, for example, with one hand, regardless of the difference in sealing strength or the pressure from the inside. [Means for Solving the Problems]

[0007] [1] A sheet including at least a core layer made of resin, the core layer including polypropylene, and the cohesive strength of the core layer being 0.3 kgf / 15 mm or more and 3.0 kgf / 15 mm or less. [2] The sheet according to [1], wherein the layer thickness of the core layer is 30% or more and 100% or less of the thickness of the sheet. [3] The sheet according to [1] or [2], having a thickness of 200 μm or more. [4] The sheet according to any one of [1] to [3], wherein the layer thickness of the core layer is 60 μm or more. [5] The sheet according to any one of [1] to [4], wherein the core layer has a sea-island structure in which a dispersed phase of a second resin different from the first resin is formed in the first resin. [6] The sheet according to [5], wherein the first resin and the second resin are any of polypropylene, polyethylene, or polystyrene, and at least one of the first resin and the second resin is polypropylene. [7] The first resin is polypropylene, and the second resin is any one of polypropylene, polyethylene, or polystyrene, the sheet according to [5]. [8] The mass ratio of the first resin to the second resin is greater than 1:1 and less than or equal to 7:1, the sheet according to any one of [5] to [7]. [9] The difference in melt flow rate of the first resin and the second resin under the measurement conditions of 230°C is 0.1 g / 10 min or more and 15.0 g / 10 min or less, the sheet according to any one of [5] to [8].

[10] The difference between the melt flow rate of the first resin under the measurement conditions of 230°C and the melt flow rate of the second resin under the measurement conditions of 190°C is 0.1 g / 10 min or more and 7.5 g / 10 min or less, the sheet according to [7].

[11] Further including at least any one selected from the group consisting of a surface layer, a barrier layer, and an adhesive layer, the sheet according to any one of [1] to

[10] .

[12] The sheet includes the barrier layer, and the core layer is laminated on both sides of the barrier layer, the sheet according to

[11] .

[13] A container formed by molding the sheet according to any one of [1] to

[12] .

[14] A first container body in which a sheet including at least a core layer made of resin is molded, and a second container body joined to the first container body to form a storage space between the first container body and the second container body, the core layer includes polypropylene, and the first container body can be opened by cohesive fracture along a planned fracture line crossing the joint between the first container body and the second container body, the container.

[15] A notch is formed on the front or back surface of the first container body along the planned fracture line, the container according to

[14] .

[16] The notch is formed across the joint and is partially filled by the joint, the container according to

[15] .

[17] The notch is partially formed on at least one of the starting side or the ending side of the planned fracture line and does not cross the joint, the container according to

[15] .

[18] The planned breaking line is along the MD (Machine Direction) of the sheet, and the container according to any one of

[14] to

[17] .

[19] The first container body includes a recess and a flange portion extending outward from the opening edge of the recess, and the joint portion is formed at least on the flange portion, and the container according to any one of

[14] to

[18] .

[20] The flange portion includes an outward projecting portion in a part of the circumferential direction, the joint portion includes a portion projecting along the projecting portion, and the planned breaking line passes through at least the projecting portion, and the container according to

[19] .

[21] The cohesive strength of the core layer is 0.3 kgf / 15 mm or more and 3.0 kgf / 15 mm or less, and the container according to any one of

[14] to

[20] .

Advantages of the Invention

[0008] According to the above configuration, by applying a force to the container body formed of the sheet from a predetermined direction, the container body can be cohesively broken to open the container. Therefore, regardless of the difference in seal strength or the pressure from the inside, for example, easy opening with one hand or the like becomes possible.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0011] FIG. 1 is a diagram showing a container according to an embodiment of the present invention. The container 100 includes a container body 110 (first container body) and a lid body 130 (second container body). In the illustrated example, the container body 110 has a substantially circular planar shape and includes a cup-shaped recess 111 and a flange portion 112 extending outward from the periphery of the recess 111. The lid body 130 is a film-like member that covers the opening of the recess 111, and is joined to the container body 110 by heat sealing or ultrasonic sealing or the like at a joining portion 140 formed on the flange portion 112. In the container 100, a storage space is formed between the container body 110 and the lid body 130. Note that a container including only the container body 110 before the lid body 130 is joined may be provided. In the illustrated example, a tab 113, which is an outward projecting portion in a part of the circumferential direction, is formed on the flange portion 112, and a tab 131 is similarly formed on the lid body 130, and the joining portion 140 includes a portion projecting along the tabs 113 and 131.

[0012] FIG. 2 is a top view of the container shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2. As shown, in the container 100, a notch 114 is formed on the surface of the flange portion 112. For the sake of convenience in this specification, the side where the lid 130 is joined by the joint 140 in the container body 110 is described as the front surface, and the opposite side is described as the back surface, but this definition has no meaning beyond this. The notch 114 crosses the joint 140 that projects along the tab 113. As shown in FIG. 2, the notch 114 is formed from the outside of the joint 140 that defines the outer edge of the storage space between the container body 110 and the lid 130, crosses the joint 140, and enters the inside of the joint 140, that is, the inside of the storage space, near the center of the tab 113, and then crosses the joint 140 again and exits to the outside of the storage space. When the resin is melted by heat sealing or the like at the joint 140, the notch 114 formed on the surface of the flange portion 112 is partially filled with the melted resin at the portion crossing the joint 140, so that the notch 114 does not communicate the inside and outside of the storage space, and the airtightness of the storage space is maintained. When airtightness is not necessarily required, the notch 114 formed on the surface of the flange portion 112 may not be filled at the portion crossing the joint 140. Alternatively, a notch may be formed on the back surface instead of the surface of the flange portion 112.

[0013] As described below, in the present embodiment, the container body 110 is formed by molding the sheet 10. As shown in FIG. 3, when a force is applied from the back side of the flange portion 112 with the tab 113, the sheet 10 is cohesively broken along the notch 114, and the flange portion 112 breaks in the middle of the tab 113. Since the notch 114 is formed across the joint portion 140 as described above, when the flange portion 112 breaks along the notch 114, the outer edge of the storage space defined by the joint portion 140 is torn, and the storage space communicates with the outside. In the present embodiment, the container 100 can be easily opened, for example, with one hand in this way. Such an opening method can be realized regardless of the sealing strength between the container body 110 and the lid body 130, so it is not necessary to make the conditions such as the sealing temperature during manufacturing strict. Further, since the seal is not peeled off by the internal pressure, even a low-viscosity content does not splash, and furthermore, the degree of freedom in the container shape and the position of the extraction portion is increased.

[0014] As will be further described later, the sheet 10 includes, for example, one or more layers 11 laminated on the front surface side, a barrier layer 12, and one or more layers 13 laminated on the back surface side. In such a case, as shown in FIG. 3, it is preferable that the notch 114 is formed only in the layer 11 on the front surface side so as not to reach the barrier layer 12. Thereby, the notch 114 can be formed without affecting the function of the barrier layer 12. The sheet 10 may include a layer other than the core layer, such as the barrier layer 12, for example. In order to realize the opening by the breakage of the flange portion 112 as described above, it is preferable that the cohesive strength of the core layer is low, and it is preferable that the layer thickness of the core layer with low cohesive strength is 30% or more and 100% or less of the thickness of the sheet 10. The layer thickness of the core layer is more preferably 50% or more, and even more preferably 60% or more, based on the thickness of the sheet 10. Further, in order for the flange portion 112 to break without bending when the above-described force is applied, it is preferable to ensure rigidity by having the sheet 10 have a certain thickness. From this viewpoint, the thickness of the sheet 10 is preferably 200 μm or more, more preferably 250 μm or more, and even more preferably 300 μm or more. The upper limit of the thickness of the sheet 10 is not particularly limited, but is, for example, 1500 μm or less. The layer thickness of the core layer is preferably 60 μm or more, more preferably 100 μm or more, and even more preferably 120 μm or more.

[0015] Figure 4 is a diagram showing a first example of the laminated structure of the sheet according to an embodiment of the present invention. In the illustrated example, the sheet 10 includes a surface layer 11A, first base material layers 11B and 13C, second base material layers 11C and 13B, adhesive layers 11D and 13A, and a barrier layer 12. The surface layer 11A, the first base material layer 11B, the second base material layer 11C, and the adhesive layer 11D correspond to the layer 11 on the front surface side of the sheet 10 shown in FIG. 3, and the adhesive layer 13A, the second base material layer 13B, and the first base material layer 13C correspond to the layer 13 on the back surface side. The surface layer 11A, the first base material layers 11B and 13C, and the second base material layers 11C and 13B are each formed of a resin containing at least any one of the group consisting of, for example, polyolefin, polystyrene, and polyester. Examples of polyolefin include polypropylene such as homopolypropylene (HPP), random polypropylene (RPP), or block polypropylene (BPP), polyethylene such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), or linear low-density polyethylene (LLDPE), and linear ethylene-α-olefin copolymer. An example of polyester is polyethylene terephthalate (PET). Materials other than resin may be added to each layer, such as an inorganic filler such as talc for improving the rigidity of the base material layer.

[0016] The barrier layer 12 is formed, for example, by extrusion molding a resin composition containing one or a mixture of two or more of ethylene-vinyl alcohol copolymer (EVOH), MX nylon (MXNy), polyvinylidene chloride (PVDC), or polyacrylonitrile (PAN), or by coating a layer of an inorganic material such as silica, alumina, aluminum, or silicon nitride, an organic material such as polyvinyl alcohol (PVA), or an organic-inorganic hybrid material such as silica / PVA. The adhesive layers 11D and 13A are formed of, for example, a urethane-based elastomer, a styrene-based elastomer, maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, or ethylene vinyl acetate (EVA). By laminating the barrier layer 12, the sheet 10 can be provided with gas barrier properties, for example, suppressing the oxidation of the contents of the container 100.

[0017] FIG. 5 is a diagram showing a second example of the laminated structure of the sheet according to the embodiment of the present invention. In the illustrated example, the sheet 10 includes a surface layer 11A, first base material layers 11B and 13C, and second base material layers 11C and 13B. The configuration of each layer is the same as that of the example in FIG. 4. Thus, the sheet 10 may have a laminated structure that does not include a barrier layer or an adhesive layer. Further, in the above example, the first base material layer and the second base material layer having different resin compositions are laminated, but a single base material layer may be laminated. The sheet 10 may be composed of a single layer, or may include more layers than the above example.

[0018] In each layer of the sheet 10 as described above, at least a part of the polyethylene may be biomass-derived polyethylene (bio-polyethylene). Bio-polyethylene is produced, for example, by fermentation, fungal fermentation, chemical change, or culture extraction using corn, cassava, sugarcane, sweet potato, palm oil, soybean, rapeseed, etc. as raw materials. Further, at least a part of the polypropylene may be biomass-derived polypropylene (bio-polypropylene). Bio-polypropylene can be obtained, for example, by fermenting molasses of sorghum, which is an inedible plant, with microorganisms to produce an intermediate material and then dehydrating it. Note that the entire amount of polyethylene and polypropylene may be bio-polyethylene or bio-polypropylene, or polyethylene or polypropylene derived from fossil fuels and bio-polyethylene or bio-polypropylene may be used in combination. Further, polypropylene and polyethylene may be composed of any one of the resins exemplified above, or two or more kinds may be used in combination.

[0019] Sheet 10 has the property of being easily cohesively disrupted. For example, in the example described above with reference to FIGS. 4 and 5, the first base material layers 11B and 13C and the second base material layers 11C and 13B can be used as the core layer. For example, when the layer thickness of either the first base material layers 11B and 13C or the second base material layers 11C and 13B is large, only one of them may be used as the core layer. The core layer may include layers laminated on both sides of the barrier layer as in the illustrated example, or only the layer laminated on one side may be the core layer. In order to give the sheet 10 the property of being easily cohesively disrupted, the layer thickness of the core layer occupies, for example, 30% or more of the thickness of the sheet 10. The surface layer 11A may be included in the core layer. In this case, in the example of FIG. 5, the entire sheet 10 is the core layer, that is, the layer thickness of the core layer becomes 100% of the thickness of the sheet 10.

[0020] From the viewpoint of facilitating the opening of the container 100 as described above, the cohesive strength of the core layer is 3.0 kgf / 15 mm or less, preferably 2.2 kgf / 15 mm or less, more preferably 1.8 kgf / 15 mm or less, and still more preferably 1.5 kgf / 15 mm or less. Also, from the viewpoint of ensuring the rigidity required for the container body 110 as the entire sheet 10, the cohesive strength of the core layer is 0.3 kgf / 15 mm or more, preferably 0.4 kgf / 15 mm or more, and more preferably 0.5 kgf / 15 mm or more. The above-described cohesive strength can be measured both in the sheet state and in the container state. Specifically, the cohesive strength of the core layer is measured by the following method. 1. A film of a sealant compatible with the resin having the largest amount in the core layer and a sheet made of the core layer are heat-sealed to prepare a section cut to a width of 15 mm. 2. The heat-sealed sealant film is peeled off at a speed of 300 mm / min in the 180° direction in the longitudinal direction of the obtained section, and the seal strength is measured. 3. This measurement is performed three times at intervals of 10°C, and the cohesive strength of the core layer is taken as the seal strength when the value of (average value of the seal strength at the temperature)÷(average value of the seal strength at the temperature - 10°C) is 120% or less for two consecutive conditions.

[0021] A sheet composed of a core layer made of polypropylene and polyethylene described in Table 1 was created. All of the obtained sheets had a sea-island structure in which a dispersed phase of polyethylene was formed within polypropylene. The cohesive strength measured by the above method for the obtained sheets is shown in Table 1.

[0022] In the case of a sheet or container where the core layer is not exposed on the surface, such as 11C and 13B being the core layers and 11A, 11B, and 13C being the core layers in FIG. 5, the core layer is exposed by peeling the layers, the core layer and the film are heat-sealed, and the measurement of the above seal strength is carried out. When the core layer includes a plurality of layers, such as the first base material layer 11B, 13C and the second base material layer 11C, 13B in the above example, it is sufficient if the layer with the lowest cohesive strength is within the above range.

[0023] [Table 1]

[0024] FIG. 6A and FIG. 6B are diagrams schematically illustrating a configuration for reducing the aggregation strength of the core layer. In the present embodiment, the core layer (for example, the first base material layers 11B and 13C or the second base material layers 11C and 13B in the above example) may have a sea-island structure in which a dispersed phase of polyethylene PE is formed in polypropylene PP. In the example of FIG. 6A, the dispersed phase of polyethylene PE is substantially spherical. As in the example of FIG. 6B, the dispersed phase of polyethylene PE may have a shape stretched in the MD (Machine Direction) during the production of the sheet 10. In a sea-island structure such as these examples, since the interfacial strength between the sea portion (the first resin) and the island portion (the second resin forming the dispersed phase) is not large, as shown, cracks are likely to enter between the sea portion and the island portion, thereby reducing the aggregation strength of the core layer. The sea portion may contain, in addition to the first resin, other resins compatible with the first resin. Further, the island portion may contain, in addition to the second resin, other resins compatible with the second resin. The proportion of the first resin among the resins contained in the sea portion, and the proportion of the second resin among the resins contained in the island portion may each be 50% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more, and may also be 100% by mass or less, 99% by mass or less, 90% by mass or less, or 80% by mass or less.

[0025] The above-described sea-island structure is not limited to the example where a dispersed phase of polyethylene is formed in polypropylene. As non-limiting examples, any one of polypropylene, polyethylene, or polystyrene can be configured as the first resin and the second resin, and polypropylene can be configured as at least one of the first resin and the second resin. For example, a dispersed phase of polystyrene or polypropylene may be formed in polypropylene. Also, a dispersed phase of polypropylene may be formed in polyethylene. A dispersed phase of polypropylene may be formed in polystyrene. The first resin is preferably polypropylene. From the perspective of forming the above-described sea-island structure and reducing the cohesive strength of the core layer, the mass ratio of the first resin to the second resin that forms a dispersed phase in the first resin is preferably greater than 1:1 and not more than 7:1. In this case, the content of the first resin (in 1% units) is 51% by mass or more and 87% by mass or less, and the content of the second resin (in 1% units) is 13% by mass or more and 49% by mass or less. Also, from the same perspective, the difference in the melt flow rate between the first resin and the second resin is preferably 0.1 g / 10 min or more and 15.0 g / 10 min or less at 230°C, more preferably 0.2 g / 10 min or more and 13.0 g / 10 min or less, and even more preferably 2.0 g / 10 min or more and 10.0 g / 10 min or less. Also, from the same perspective, the difference between the melt flow rate of the first resin under the measurement conditions at 230°C and the melt flow rate of the second resin under the measurement conditions at 190°C is preferably 0.1 g / 10 min or more and 7.5 g / 10 min or less, more preferably 0.15 g / 10 min or more and 6.5 g / 10 min or less, and even more preferably 1.0 g / 10 min or more and 5.0 g / 10 min or less.

[0026] FIG. 7 is a view showing another example of the container according to the embodiment of the present invention. In the illustrated example, in the container 100 configured in the same manner as the example of FIG. 1, notches 114A and 114B are formed that do not cross the joint portion 140. More specifically, the notch 114A is formed on the starting point side of the planned break line L that crosses the joint portion 140, and the notch 114B is formed on the ending point side. In this specification, for convenience, both ends of the planned break line L are described as the starting point side and the ending point side, respectively, but this has no meaning other than this definition. That is, in the above description, the notch 114A is on the starting point side and the notch 114B is on the ending point side, but the reverse may also be true. The planned break line L is a line along which the sheet 10 constituting the container body 110 undergoes cohesive fracture when a force is applied to the container body 110 from a predetermined direction, as described above with reference to FIG. 3. In the example of FIG. 2, the notch 114 is formed along the entire length of the planned break line L. In the example of FIG. 7, the notches 114A and 114B are partially formed on the starting point side and the ending point side of the planned break line L as described above. Also in this case, by the cohesive fracture of the sheet 10 progressing along the planned break line L, which is the extension line of the notches 114A and 114B, a part of the tab 113 breaks the flange portion 112 and the container 100 can be opened. Note that only one of the notches 114A and 114B may be formed.

[0027] Here, FIG. 7 shows the MD (Machine Direction) at the time of manufacturing the sheet 10 that forms the container body 110. Generally, since the sheet 10 has a property of being easily broken in the direction along the MD, by setting the direction of the planned break line L as the MD and forming the notch along the MD, it is possible to easily cause the break of the sheet 10 in the intended direction and facilitate the opening of the container 100. The MD corresponds to the orientation direction of the resin constituting the core layer of the sheet. That is, it is preferable that the direction of the planned break line L and the direction of the notch are along the orientation direction, and it is preferable that they are in the direction of ±20° of the orientation method. The MD is also shown in FIG. 2.

[0028] FIG. 8 is a view showing yet another example of the container according to the embodiment of the present invention. Also in the illustrated example, in the container 100 configured in the same manner as the example of FIG. 1, notches 114C and 114D that do not cross the joint portion 140 are formed. In the example of FIG. 8, the planned break line L obliquely crosses the tab 113, and a part thereof comes off the tab 113 and extends to another part of the flange portion 112. By setting the direction of the planned break line L in this way, it is possible to prevent the container from being opened due to a force being applied to the flange during manufacturing or transportation, causing the flange to break. That is, it can be made into a container that is opened only when the user intends to take out the contents. The notches 114C and 114D are partially formed on the starting side and the ending side of the planned break line L, respectively. The notch 114C is formed in the middle of the tab 113, and the notch 114D is formed in a part of the flange portion 112 close to the tab 113. Only one of the notches 114C and 114D may be formed. Also, similar to the embodiment according to FIG. 2, the notch may be formed so as to cross the joint portion 140 and the inside of the joint portion 140 (inside the storage space). Even in such a case, by setting the direction of the planned break line L as MD and forming the notch along MD, it is possible to easily cause the sheet 10 to break in the intended direction and facilitate the opening of the container 100.

[0029] FIG. 9 is a diagram showing still another example of the container according to the embodiment of the present invention. Also in the illustrated example, in the container 100 configured in the same manner as the example of FIG. 1, a notch 114E that does not cross the joint portion 140 is formed. In the example of FIG. 9, the planned break line L longitudinally cuts the tab 113, the starting point is the tip of the tab 113, and the ending point is near the boundary between the inner flange portion 112 and the recess 111 inside the tab 113. By setting the direction of the planned break line L in this way, it is possible to prevent the container from being opened due to a force being applied to the flange during manufacturing or transportation and the flange cracking. That is, it can be made into a container that is opened only when the user intends to take out the contents. In such a case, the ending point of the planned break line L does not necessarily have to be clearly specified. The notch 114E is partially formed on the starting point side of the planned break line L, that is, at the tip of the tab 113. Even in such a case, by setting the direction of the planned break line L as the MD and forming the notch along the MD, it is possible to make the sheet 10 more likely to break in the intended direction and facilitate the opening of the container 100. Note that the notch may be formed so as to longitudinally cut the joint portion 140 and also longitudinally cut the inside of the joint portion 140 (the inside of the storage space).

[0030] Note that in the examples of the embodiments of the present invention described above, notches are formed on the front or back surface of the sheet 10 that constitutes the container body 110 in the container 100, but the notches do not necessarily have to be formed. Since the sheet 10 is likely to break in the direction along the MD as described above, for example, by molding the container body 110 so that the MD crosses the tab 113, the sheet 10 can be cohesively broken and the flange portion 112 can be broken by applying a force near the tip of the tab 113 without forming a notch, and the container can be opened.

[0031] In the example of the above-described embodiment, the container 100 includes the container body 110 as the first container body and the lid 130 as the second container body. However, this relationship may be reversed. That is, for example, the first container body that undergoes cohesive fracture when a predetermined force is applied may be the lid, and this lid may be joined to the second container body including the cup-shaped recess and the flange portion. Regarding the shapes and joining methods of the first and second container bodies, various known container configurations can be adopted and are not particularly limited. Therefore, depending on the joining method, the fracture prediction line due to the cohesive fracture of the first container body may not cross the joint between the first container body and the second container body.

Explanation of Reference Numerals

[0032] 100... container, 110... container body, 111... recess, 112... flange portion, 113... tab, 114, 114A, 114B, 114C, 114D, 114E... notch, 130... lid, 131... tab, 140... joint, L... fracture prediction line, 10... sheet, 11... surface-side layer, 11A... surface layer, 11B... first base material layer, 11C... second base material layer, 11D... adhesive layer, 12... barrier layer, 13... back-side layer, 13A... adhesive layer, 13B... second base material layer, 13C... first base material layer, PE... polyethylene, PP... polypropylene.

Claims

1. A sheet comprising at least a core layer made of resin, wherein the core layer contains polypropylene, and the cohesive strength of the core layer is 0.3 kgf / 15 mm or more and 3.0 kgf / 15 mm or less.

2. The sheet according to claim 1, wherein the layer thickness of the core layer is 30% or more and 100% or less of the thickness of the sheet.

3. The sheet according to claim 1 or 2, having a thickness of 200 μm or more.

4. The sheet according to any one of claims 1 to 3, wherein the layer thickness of the core layer is 60 μm or more.

5. The sheet according to any one of claims 1 to 4, wherein the core layer has a sea-island structure in which a dispersed phase of a second resin different from the first resin is formed in the first resin.

6. The sheet according to claim 5, wherein the first resin and the second resin are any one of polypropylene, polyethylene, or polystyrene, and at least one of the first resin and the second resin is polypropylene.

7. The sheet according to claim 5, wherein the first resin is polypropylene and the second resin is any one of polypropylene, polyethylene, or polystyrene.

8. The sheet according to any one of claims 5 to 7, wherein the mass ratio of the first resin to the second resin is greater than 1:1 and 7:1 or less.

9. The sheet according to any one of claims 5 to 8, wherein the difference in melt flow rate of the first resin and the second resin under measurement conditions of 230 °C is 0.1 g / 10 min or more and 15.0 g / 10 min or less.

10. The sheet according to claim 7, wherein the difference in melt flow rate of the first resin under measurement conditions of 230 °C and the melt flow rate of the second resin under measurement conditions of 190 °C is 0.1 g / 10 min or more and 7.5 g / 10 min or less.

11. The sheet according to any one of claims 1 to 10, further comprising at least any one selected from the group consisting of a surface layer, a barrier layer, and an adhesive layer.

12. The sheet includes the barrier layer, and the core layer is laminated on both sides of the barrier layer. The sheet according to claim 11.

13. A container formed by molding the sheet according to any one of claims 1 to 12.

14. A first container body formed with a sheet including at least a core layer made of resin, and a second container body joined to the first container body to form a storage space therebetween. The core layer contains polypropylene. A container that can be opened by cohesively breaking the first container body along a planned breaking line that crosses the joint between the first container body and the second container body.

15. The container according to claim 14, wherein a notch is formed on the front or back surface of the first container body along the planned breaking line.

16. The container according to claim 15, wherein the notch is formed across the joint and is partially filled by the joint.

17. The container according to claim 15, wherein the notch is partially formed on at least one of the starting side or the ending side of the planned breaking line and does not cross the joint.

18. The container according to any one of claims 14 to 17, wherein the planned breaking line is along the MD (Machine Direction) of the sheet.

19. The first container body includes a recess and a flange portion extending outward from the opening edge of the recess. The container according to any one of claims 14 to 18, wherein the joint is formed at least on the flange portion.

20. The flange portion includes an outward projecting portion in a part of the circumferential direction. The joint includes a portion projecting along the projecting portion. The container according to claim 19, wherein the planned breaking line passes at least through the projecting portion.

21. The container according to any one of claims 14 to 20, wherein the cohesive strength of the core layer is 0.3 kgf / 15 mm or more and 3.0 kgf / 15 mm or less.

Images