Packaging

Abstract

The present invention provides a packaging body comprising a resin container and a lid made of resin film, which can maintain the freshness of fruits and vegetables when they are packaged and stored, and can also suppress swelling of the storage area. [Solution] A package 1 in which a resin container 12 and a lid material 11 made of resin film are sealed together, and fruits and vegetables 9 are packaged, wherein the lid material 11 has an opening area of ​​1 × 10 -5 ~0.1mm 2 One or more through holes 110 are provided, and the total opening area of ​​the through holes 110 in the lid material 11 is a mm 2 Let b kg be the mass of the produce 9, and package 1 such that a / b is between 0.01 and 0.5.

Description

Technical Field

[0001] The present invention relates to a package.

Background Art

[0002] A package composed of a resin container and a lid material made of a resin film sealed together has been widely used as a food package. Among such packages, it is known that a package provided with fine through-holes in the lid material can adjust the environment inside its storage part.

[0003] As such a package, for example, a package in which pickles are packaged, and the lid material has through-holes with a hole area of 1×10 ~0.1 mm 2 or more, and the total hole area of the through-holes per 1 kg of the packaged amount of pickles is 1×10 -5 ~2 mm 2 is disclosed (see Patent Document 1).

[0004] Since pickles are fermented foods, during the storage of the package, fermentation and aging of the pickles proceed inside the storage part of the package, and carbon dioxide gas is generated from the pickles accordingly. Then, in a normal package, the storage part bulges, and in that case, consumers are likely to misjudge that there is a problem with the quality of the pickles, and the commercial value of the package decreases. Furthermore, when the storage part bulges like this, the stacking structure in the state where the packages are stacked on top of each other is unstable, so it is difficult to stack and place the packages on top of each other (for example, storage, display, etc.), and the placement form is restricted.

[0005] On the other hand, in the package disclosed in Patent Document 1, through-holes are provided in the lid material, and the total hole area of the through-holes per 1 kg of the packaged amount of pickles is limited to a specific range, so that swelling of the storage part is suppressed, visual recognition of the through-holes is suppressed, and movement of liquid substances and odors from the storage part is suppressed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, the package disclosed in Patent Document 1 only assumes pickles as the object to be packaged and does not aim to maintain the freshness of the object to be packaged during storage of the package. For example, when the object to be packaged is fresh produce, it is required that the package can maintain the freshness of the fresh produce in the packaged state without reducing it and keep it in a fresh state. During storage of a package containing fresh produce, due to the continuous respiration of the fresh produce, the concentrations of oxygen gas and carbon dioxide gas in the package (inside the storage part) change. It is known that fresh produce respires vigorously and is consumed when the oxygen gas concentration is high in the package. In contrast, with the package disclosed in Patent Document 1, the freshness of fresh produce cannot be sufficiently maintained during storage after packaging the fresh produce. Furthermore, when fresh produce is packaged in a normal package, the storage part also bulges.

[0008] An object of the present invention is to provide a package including a resin container and a lid material made of a resin film, which can maintain the freshness of fresh produce and suppress swelling of the storage part when storing the fresh produce after packaging.

Means for Solving the Problems

[0009] To solve the above problems, the present invention adopts the following configuration. [1] A package in which a resin container and a lid material made of a resin film are sealed and fresh produce is packaged, wherein the lid material has one or more through-holes with a hole area of 1×10 -5 ~0.1 mm 2 The total hole area of the through-holes in the lid material is amm 2A package, where when the mass of the fresh produce is b kg, a / b is 0.01 to 0.5. [2] The oxygen permeability of the non-aperture portion of the lid material under the conditions of a temperature of 23 °C and a relative humidity of 60%, measured in accordance with JIS K 7126-2:2006, is 100 ml / (m 2 ·day·atm) or less, for the package according to [1].

[0010] [3] The package according to [1] or [2], wherein the resin film includes a layer containing polyester or polyamide as a main component. [4] The package according to any one of [1] to [3], wherein the thickness of the lid material is 30 to 80 μm. [5] The package according to any one of [1] to [4], wherein the fresh produce is cut vegetables or cut fruits.

Advantages of the Invention

[0011] According to the present invention, there is provided a package including a resin container and a lid material made of a resin film, which can maintain the freshness of fresh produce and suppress the swelling of the storage portion when the fresh produce is packaged and stored.

Brief Description of the Drawings

[0012] [Figure 1] It is a cross-sectional view schematically showing an example of a package according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0013] ◎Package A package according to an embodiment of the present invention is a package in which a resin container and a lid material made of a resin film are sealed, and fresh produce is packaged. One or more through-holes with a hole area of 1 × 10 -5 ~0.1 mm 2 are provided in the lid material, and when the total hole area of the through-holes in the lid material is a mm 2 and the mass of the fresh produce is b kg, a / b is 0.01 to 0.5. The packaging body of this embodiment has an opening area of ​​1 × 10 in its lid material. -5 ~0.1mm 2 If one or more through holes are provided, and if a / b is 0.01 to 0.5, and if a / b is above the lower limit, swelling of the storage area in the package can be suppressed during storage of the package, and if a / b is below the upper limit, the effect of maintaining the freshness of fruits and vegetables is enhanced. For example, when the package of this embodiment is stored, swelling of the storage area is suppressed, which prevents consumers from mistakenly believing that there is a problem with the quality of the fruits and vegetables based on the appearance of the package. Furthermore, even if the packages are stacked on top of each other, the stacking structure is stable, so the way the packages are placed is not restricted.

[0014] In this specification, unless otherwise specified, "mass of produce" packaged in a package means the mass of a single piece of produce if only one piece is packaged in the package, and the total mass of all of the produce if multiple pieces are packaged in the package.

[0015] Unlike processed foods such as pickles, fresh produce does not contain additives such as preservatives or antimicrobials to enhance quality preservation, making it difficult to maintain its freshness when packaged and stored. In contrast, the packaging body of this embodiment has an opening area of ​​1 × 10 in its lid material. -5 ~0.1mm 2 The presence of one or more through-holes, along with the limitation of a / b to a specific range, not only maintains the freshness of fruits and vegetables during storage but also suppresses bulging of the storage area, resulting in a remarkable effect.

[0016] The fruits and vegetables to be packaged in this embodiment are not particularly limited. Preferred fruits and vegetables include, for example, vegetables such as cabbage, pumpkin, broccoli, carrots, onions, spinach, bell peppers, mushrooms, cucumbers, tomatoes, green peppers, sweet potatoes, lettuce, mizuna, Chinese cabbage, corn, and radishes; and fruits such as pineapple, watermelon, melon, grapefruit, oranges, citrus fruits, grapes, apples, pears, peaches, persimmons, strawberries, kiwis, and bananas.

[0017] In this embodiment, the produce is preferably cut vegetables or cut fruits. Cut vegetables and cut fruits, with their exposed cut surfaces, are more susceptible to deterioration during storage of the package compared to whole vegetables and fruits, making it difficult to maintain their freshness. However, in the packaging of this embodiment, even such easily deteriorated products can maintain their freshness sufficiently during storage of the package.

[0018] The present invention will be described in detail below with reference to the drawings. Note that, for convenience in making the features of the present invention easier to understand, the drawings may show enlarged versions of key parts, and the dimensional ratios of each component may not be the same as those in reality.

[0019] Figure 1 is a schematic cross-sectional view showing an example of the packaging according to this embodiment. The packaging 1 shown in Figure 1 consists of a resin container 12 and a lid material 11 made of resin film, which are sealed together to package multiple fruits and vegetables 9. The lid material 11 has an opening area of ​​1 × 10 -5 ~0.1mm 2 One or more through holes 110 are provided. Total opening area of ​​through holes 110 in the cover material 11 amm 2 The total mass of the 9 fruits and vegetables, b kg, and the calculated a / b ratio are between 0.01 and 0.5.

[0020] The resin container 12 is a molded body (for example, a heat-molded body) of a resin film consisting of one or more layers (which may be referred to as "resin film for containers" in this specification).

[0021] In the packaging 1, the area 121a (in this specification, such an area may be simply referred to as the "edge of the opening") on the side 12a of the resin container 12 facing the lid material 11, and the area near the peripheral edge of the lid material 11 on the side 11a of the resin container 12 facing the lid material 11 are sealed, and the storage compartment 1a is formed by the unsealed areas of these surfaces. The fruits and vegetables 9 are stored in this storage compartment 1a. In this way, the edge 121a of the opening of the resin container 12 is sealed with the lid material 11, thereby sealing the resin container 12 with the lid material 11.

[0022] The edge 121a of the opening of the resin container 12 is a region corresponding to a flange and is preferably a smooth surface. It may be either a flat or curved surface, but it is preferably flat in that it is easier to seal with the lid material 11 and the degree of airtightness of the resin container 12 by the lid material 11 is higher.

[0023] In the packaging 1, both the surface 11b of the lid material 11 opposite to the resin container 12 side and the surface 12b of the resin container 12 opposite to the lid material 11 side are exposed surfaces.

[0024] The lid material 11 is constructed by laminating a sealant layer 111, an adhesive layer 112, and an outer layer 113 in this order in the thickness direction. In the lid material 11, a through hole 110 is formed that penetrates from the surface 11b opposite to the resin container 12 side to the surface 11a on the resin container 12 side.

[0025] The opening area of ​​the through-hole 110 refers to both the area of ​​the opening created by the through-hole 110 on the side 11b of the lid material 11 opposite to the resin container 12 side, and the area of ​​the opening created by the through-hole 110 on the side 11a of the lid material 11 facing the resin container 12. If the areas of the openings on these two sides are different, the average of these areas is adopted as the opening area of ​​the through-hole 110.

[0026] The packaging of this embodiment is not limited to the packaging 1 shown in Figure 1, and for example, some components of the packaging 1 may be modified, deleted, or added without departing from the spirit of the present invention. For example, in the packaging 1, multiple fruits and vegetables 9 are packaged (stored in the storage section 1a), and six fruits and vegetables 9 are shown in cross-section. However, in the packaging of this embodiment, the number of fruits and vegetables packaged (stored in the storage section) is arbitrary and can be adjusted as appropriate depending on the purpose; there may be only one or two or more. For example, in the packaging 1, the lid material 11 is composed of a sealant layer 111, an adhesive layer 112, and an outer layer 113. However, in the packaging of this embodiment, the types and number of layers in the lid material are not limited to this and can be set as appropriate depending on the purpose.

[0027] The packaging of this embodiment may be the same as known packaging, except that it includes the lid material (using the resin film).

[0028] Next, the lid material and resin container that constitute the packaging of this embodiment will be described in more detail.

[0029] <<Lid material>> The lid material constituting the aforementioned packaging body is made of a resin film having one or more through holes. The lid material may be the same as the resin film, except that it has through holes.

[0030] The resin contained in the aforementioned resin film is not particularly limited. The resin contained in the resin film may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0031] The aforementioned resin film may consist of a single layer or of two or more layers. If the resin film consists of multiple layers, these layers may be identical or different from one another.

[0032] The resin film is preferably transparent.

[0033] In this specification, not only in the case of lid materials, "multiple layers may be identical or different from one another" means "all layers may be identical, all layers may be different, or only some layers may be identical," and further, "multiple layers are different from one another" means "at least one of the constituent materials and thickness of each layer is different from the other."

[0034] Regardless of whether the resin film is single-layer or multi-layer, examples of the resin contained in the resin film include polyolefin, polystyrene, chlorine-based resin, polyvinyl alcohol, polyvinyl acetate, polyester, polyamide, and the like.

[0035] The aforementioned polyolefin is a resin having structural units derived from olefins. Examples of polyolefins include ethylene-based polymers and propylene-based polymers.

[0036] The ethylene-based polymer is a polymer (resin) having structural units derived from ethylene, and may be polyethylene (PE, for example, a homopolymer of ethylene), or it may be an ethylene-based copolymer having structural units derived from ethylene and structural units derived from monomers other than ethylene. However, among polyolefins having structural units derived from ethylene and structural units derived from propylene, copolymers in which the number of structural units derived from propylene is greater than the number of structural units derived from ethylene are classified as propylene-based copolymers, as described later.

[0037] Examples of the polyethylene (PE) mentioned above include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), metallocene-catalyzed linear low-density polyethylene (mLLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE).

[0038] In this specification, the densities of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and metallocene-catalyzed linear low-density polyethylene (mLLDPE) are defined as 0.910 g / cm³. 3 More than 0.940g / cm 3 It is less than. The density of medium-density polyethylene (MDPE) is 0.940 g / cm³. 3 More than 0.945g / cm 3 It is less than. The density of high-density polyethylene (HDPE) is 0.945 g / cm³. 3 That's all.

[0039] Examples of the ethylene-based copolymers include ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol-vinyl acetate copolymer (also known as partially saponified ethylene-vinyl acetate copolymer), ethylene-methyl acrylate copolymer (EMA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), and ionomers (ION).

[0040] In this specification, "ionomer" means a copolymer of ethylene and one or more small amounts of monomers having acidic groups, wherein the acidic groups dissociate to generate anionic groups, and such copolymer forms an ionic crosslinking structure by the formation of a salt between the anionic groups and metal ions.

[0041] Examples of the propylene polymer include homopolypropylene (propylene homopolymer, hPP) and propylene copolymers.

[0042] Examples of the propylene copolymer include propylene-ethylene random copolymers (also known as polypropylene random copolymer, rPP), propylene-ethylene block copolymers (also known as polypropylene block copolymer, bPP), and ethylene-propylene terpolymers (also known as ethylenepropylene terpolymer, EPT).

[0043] Examples of the chlorine-based resins include chlorinated polyolefins such as polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC), which are resins having constituent units derived from monomers having a structure in which one or more hydrogen atoms in the olefin are replaced by chlorine atoms.

[0044] Examples of the aforementioned polyesters include polyethylene terephthalate (PET), modified polyethylene terephthalate, polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), and polybutylene naphthalate (PBN). Examples of the modified polyethylene terephthalate include glycol-modified polyethylene terephthalate (GPET) and dicarboxylic acid-modified polyethylene terephthalate.

[0045] Examples of the polyamide include polyamides obtained by polymerization or copolymerization of cyclic lactams (lactams with 3 or more ring members), amino acids, or nylon salts obtained by the reaction of diamines with dicarboxylic acids. Preferred polyamides, in terms of heat resistance, mechanical strength, and availability, include 6-nylon, 12-nylon, 66-nylon, nylon 6 / 66, nylon 6 / 12, and nylon 6 / 66 / 12.

[0046] Whether the resin film is single-layer or multi-layer, it may or may not contain other components (i.e., non-resin components) in addition to the resin.

[0047] The other components contained in the resin film may consist of only one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0048] The other components contained in the resin film are not particularly limited and can be arbitrarily selected depending on the purpose. Other components included in the resin film include, for example, additives known in the art. Examples of the aforementioned additives include antifogging agents, pigments, antiblocking agents, antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, viscosity reducers, viscosity thickeners, heat stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, and the like.

[0049] Regardless of whether the resin film is single-layer or multi-layer, the ratio of the resin content (parts by mass) to the total mass (parts by mass) of the resin film ([resin content (parts by mass) of the resin film] / [total mass (parts by mass) of the resin film] × 100) is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, 95% by mass or more, 97% by mass or more, or 99% by mass or more. The properties of the resin film are better when the ratio is above the lower limit. On the other hand, the aforementioned ratio is 100% by mass or less. The aforementioned ratio is typically the same as the ratio of the resin content (parts by mass) to the total content (parts by mass) of components that do not vaporize at room temperature in the resin composition that forms the resin film described later (resin content (parts by mass) of the resin composition that forms the resin film) / [total content (parts by mass) of components that do not vaporize at room temperature in the resin composition that forms the resin film] × 100). This relationship between the content of components in the resin film and the content of components in the resin composition that forms the resin film is also true for each layer when the resin film consists of multiple layers. In this context, "resin content" in the context of resin films refers to the total content of all resins if the resin film contains two or more types of resins.

[0050] In this specification, "room temperature" means a temperature that is neither cooled nor heated, i.e., a normal temperature, such as 15-25°C.

[0051] Regardless of whether the resin film is single-layer or multi-layer, the ratio of the total content (parts by mass) of polyolefin, polystyrene, chlorine-based resin, polyvinyl alcohol, polyvinyl acetate, polyester, and polyamide to the total mass (parts by mass) of the resin film is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, 95% by mass or more, 97% by mass or more, or 99% by mass or more. The properties of the resin film are better when the ratio is above the lower limit. On the other hand, the aforementioned ratio is 100% by mass or less.

[0052] Regardless of whether the resin film is single-layer or multi-layer, it is preferable that the resin film includes a layer mainly composed of polyester or polyamide. Lid materials obtained using such resin films are superior in terms of strength, such as pinhole resistance, and in that case, the characteristics of the packaging are better. When the resin film consists of multiple layers, it is preferable that the outermost layer of the resin film on the side opposite to the side sealed with the resin container in the lid material (sometimes referred to as the "outer layer" in this specification) is a layer that contains at least the above-mentioned polyester or polyamide as its main component.

[0053] In this embodiment, the statement that a resin layer contains resin (A) as its main component is not limited to the layer containing polyester or polyamide as described above, meaning that in the resin layer, the ratio of resin (A) content to the total mass of the resin layer is 50% by mass or more. This ratio may be, for example, 60% by mass or more, 70% by mass or more, 80% by mass or more, and 90% by mass or more, while being 100% by mass or less.

[0054] Regardless of whether the resin film is single-layer or multi-layer, the thickness of the resin film and lid material is preferably 30 to 80 μm, more preferably 35 to 65 μm, and may be, for example, 40 to 50 μm. When the thickness of the resin film and lid material is above the lower limit, the strength of the lid material, such as pinhole resistance, is increased, as well as the suitability of the packaging for manufacturing and the handling of the lid material. When the thickness of the resin film and lid material is below the upper limit, excessive thickness of the lid material is avoided. This makes it easier, for example, to adjust the amount of gas permeation through the through-holes, and also makes it easier to form the through-holes.

[0055] A preferred resin film consisting of multiple layers is, for example, a resin film in which a sealant layer, an adhesive layer, and an outer layer are laminated in this order in the thickness direction. The sealant layer, adhesive layer, and outer layer may each be a single layer or two or more layers. If the sealant layer, adhesive layer, or outer layer consists of multiple layers, these multiple layers may be identical or different from one another. The sealant layer, adhesive layer, and outer layer are preferably transparent.

[0056] <Sealant layer> The sealant layer (sealant layer 111 in the lid material 11 shown in Figure 1) is a layer for sealing the lid material to the resin container. The sealant layer is the outermost layer of one of the lid material and resin film layers, and is located on the outermost side in the lamination direction of the sealant layer, adhesive layer and outer layer.

[0057] The sealant layer is preferably a resin layer containing one or more types of resins. The sealant layer is preferably an unstretched layer.

[0058] The sealant layer may be a non-easy-peel type sealant layer or an easy-peel type sealant layer (easy-peel layer). The non-easy-peel type sealant layer may be a fully-sealing type sealant layer (a sealant layer that is difficult to peel) or a sealant layer with mild peelability. In this embodiment, the sealant layer is preferably an easy-peel layer. A package with such a lid material (resin film) is particularly suitable for packaging fresh produce.

[0059] Examples of the easy-peel layer include layers that exhibit cohesive peelability, interfacial peelability, or interlayer peelability.

[0060] The Easy Peel layer, which exhibits cohesive peelability, exhibits peelability due to its cohesive breakdown. An example of an easy-peel layer exhibiting cohesive peelability is a resin layer containing two incompatible resins. Examples of the combination of two incompatible resins include combinations of polyolefins, and combinations of ethylene-vinyl acetate copolymer and polystyrene.

[0061] Examples of the two immiscible polyolefins included in the easy-peel layer include ethylene-based polymers and propylene-based polymers. The polyolefin, ethylene-based polymer, and propylene-based polymer contained in the easy-peel layer are the same as those contained in the resin film described above.

[0062] If the Easy Peel layer contains two incompatible polyolefins, namely an ethylene-based polymer and a propylene-based polymer, it may or may not contain other components.

[0063] Other components included in the easy-peel layer include resin components that do not fall under either ethylene polymers or propylene polymers, as well as the additives described as other components included in the resin film.

[0064] The ethylene polymer, propylene polymer, and other components contained in the easy-peel layer may each be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0065] In the easy-peel layer, the ratio of the total content of the two incompatible resins to the total mass of the easy-peel layer is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, 95% by mass or more, 97% by mass or more, or 99% by mass or more. When the ratio is above the lower limit, the sealing properties of the easy-peel layer are improved. On the other hand, the aforementioned ratio is 100% by mass or less.

[0066] For example, if the easy-peel layer contains an ethylene polymer and a propylene polymer as two incompatible resins, the ratio of the total content of the ethylene polymer and the propylene polymer to the total mass of the easy-peel layer is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, 95% by mass or more, 97% by mass or more, or 99% by mass or more. When the ratio is above the lower limit, the sealing properties of the easy-peel layer are improved. On the other hand, the aforementioned ratio is 100% by mass or less.

[0067] The easy-peel layer exhibiting interlayer delamination is composed of two or more layers, the first layer on the side of the resin container being completely sealed to the resin container, while the second layer on the opposite side of the resin container is easily peeled off from the first layer by the lid peeling operation. The first layer preferably contains the same type of resin as the resin contained in the area that is sealed with the lid material of the resin container.

[0068] Regardless of whether the sealant layer is a non-easy-peel type sealant layer or an easy-peel layer, the ratio of the thickness of the sealant layer to the thickness of the resin film (lid material) ([thickness of sealant layer] / [thickness of resin film (lid material)] × 100) is preferably 8 to 90%, more preferably 20 to 75%, and even more preferably 30 to 60%, for example, it may be any of 30 to 40%, 40 to 50%, and 50 to 60%. If the ratio is above the lower limit, the peel strength of the sealant layer will be higher. If the ratio is below the upper limit, the thickness of the sealant layer will not be excessive. When the sealant layer consists of multiple layers, it is preferable that the ratio of the total thickness of these multiple layers to the thickness of the resin film (lid material) is within the above numerical range. This applies not only to the sealant layer but also to layers other than the sealant layer, as described later.

[0069] In this specification, including in the case of the sealant layer described above, the ratio of the thickness of any layer constituting the resin film (lid material) to the thickness of the resin film (lid material) is described, but the sum of the ratios described for each layer shall not exceed 100%.

[0070] Regardless of whether the sealant layer is a non-easy-peel type sealant layer or an easy-peel layer, the thickness of the sealant layer is preferably 2 to 70 μm, more preferably 6 to 60 μm, and even more preferably 9 to 50 μm, for the same reasons as in the thickness ratio described above. When the sealant layer consists of multiple layers, it is preferable that the total thickness of these multiple layers is within the above numerical range. This applies not only to the sealant layer but also to layers other than the sealant layer, as described later.

[0071] <Outer layer> The outer layer (outer layer 113 in the lid material 11 shown in Figure 1) provides protection to the other layers within the lid material. The outer layer is the outermost layer of the other component, the lid material and the resin film, and is located on the outermost side of the other component in the lamination direction of the sealant layer, adhesive layer and outer layer.

[0072] The outer layer is preferably a resin layer containing one or more types of resins. The outer layer is preferably a biaxially stretched layer.

[0073] Examples of preferred resins to be included in the outer layer include polyester and polyamide. Examples of polyester and polyamide included in the outer layer include those similar to those included in the sealant layer described above.

[0074] If the outer layer contains polyester or polyamide as the resin, it may or may not contain other components.

[0075] Other components included in the outer layer include resin components that do not fall under either polyester or polyamide, as well as the additives described as other components included in the resin film.

[0076] The polyester, polyamide, and other components contained in the outer layer may each be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0077] In the outer layer, the ratio of the total content of polyester and polyamide to the total mass of the outer layer is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, 95% by mass or more, 97% by mass or more, or 99% by mass or more. When the ratio is above the lower limit, the effect obtained by the lid material having an outer layer is further enhanced. On the other hand, the aforementioned ratio is 100% by mass or less.

[0078] The ratio of the thickness of the outer layer to the thickness of the resin film (lid material) is preferably 15-50%, more preferably 20-45%, and may be, for example, 20-35%, 25-40%, or 30-45%. When the ratio is above the lower limit, the effect obtained by the lid material having an outer layer is increased. When the ratio is below the upper limit, the thickness of the outer layer is avoided.

[0079] The thickness of the outer layer is preferably 6 to 40 μm, and more preferably 8 to 30 μm, for the same reasons as for the thickness ratio described above.

[0080] <Adhesive layer> The adhesive layer adheres to any two layers of the lid material and resin film (for example, the sealant layer and the outer layer), but is not the outermost layer of the lid material and resin film. The placement and number of adhesive layers in the lid material and resin film can be arbitrarily selected according to the purpose. If adhesive layers are provided in two or more locations within the lid material and the resin film, these two or more adhesive layers may be identical or different.

[0081] The adhesive layer is preferably a resin layer containing an adhesive resin.

[0082] The adhesive layer may or may not contain other components besides the adhesive resin. Other components included in the adhesive layer include the additives described as other components included in the resin film.

[0083] In the adhesive layer, the ratio of the adhesive resin content to the total mass of the adhesive layer is preferably 80 to 100% by mass or less.

[0084] The ratio of the thickness of the adhesive layer to the thickness of the resin film (lid material) is preferably 1 to 10%. The thickness of the adhesive layer is preferably 0.5 to 4.5 μm, and more preferably 1 to 2 μm. When the ratio and the thickness of the adhesive layer are greater than or equal to the lower limit, the adhesive strength of the adhesive layer is increased. When the ratio and the thickness of the adhesive layer are less than or equal to the upper limit, it is avoided that the thickness of the adhesive layer becomes excessive.

[0085] <Other layers> A resin film comprising a sealant layer, an adhesive layer, and an outer layer may or may not include other layers that are not any of these layers. The types of other layers mentioned above are not particularly limited and can be arbitrarily selected according to the purpose. The thickness of the other layers is not particularly limited and can be arbitrarily selected depending on the type of the other layers. If the resin film includes the aforementioned other layers, the arrangement position and number of the aforementioned other layers in the resin film are not particularly limited and can be arbitrarily selected according to the type or purpose of the aforementioned other layers.

[0086] <Other components of the lid material and resin film> The shape of the opening portion of the through-hole on the surface of the lid material, and the shape of the opening portion of the through-hole in a cross-section perpendicular to its longitudinal direction, are not particularly limited and may be, for example, circular; elliptical; polygonal shape such as triangular or quadrilateral; or a combination of two or more shapes selected from the group consisting of circles, ellipses, and polygons. However, in terms of ease of forming the through-hole, higher strength of the lid material, and less conspicuous presence of the through-hole, the shape is preferably circular or substantially circular. In this specification, "approximately circular shape" means a shape that is not strictly circular, but is close enough to be treated as such.

[0087] In this specification, unless otherwise specified, "opening of a through hole" means both the opening of a through hole on the surface of the cover material described above and the opening of the through hole in a cross-section perpendicular to its longitudinal direction.

[0088] The number of through holes provided in the lid material may be one or more; it may be one or two or more. The number of through-holes in the lid material is preferably 1 to 10, more preferably 1 to 7, and may be, for example, 1 to 3, 2 to 4, or 5 to 7. When the number of through-holes is equal to or greater than the lower limit, the opening area of ​​each through-hole is prevented from becoming excessively large, and as a result, liquids and odors from fruits and vegetables inside the packaging are less likely to move outside the packaging. When the number of through-holes is equal to or less than the upper limit, the strength of the lid material is increased, and the presence of the through-holes becomes less noticeable. The number of through holes provided in the lid material should preferably be adjusted appropriately according to the opening area of ​​each through hole.

[0089] The opening area of ​​one through-hole in the lid material is 1 × 10 -5 ~0.1mm 2 For example, 0.0001 to 0.1 mm 2 , 0.001~0.1mm 2, and 0.01~0.1mm 2 Either of these is fine, or 1 × 10 -5 ~0.01mm 2 It may be 0.0001~0.01mm 2 , and 0.001~0.01mm 2 Either of the following is acceptable. By ensuring that the opening area of ​​each through-hole is greater than or equal to the lower limit, the number of through-holes in the lid material is avoided to be excessive, resulting in increased strength of the lid material and making the presence of the through-holes less noticeable. By ensuring that the opening area of ​​each through-hole is less than or equal to the upper limit, liquids and odors derived from fruits and vegetables inside the storage compartment of the packaging are less likely to move outside the storage compartment.

[0090] The total opening area a of the through holes in the cover material is the sum of the opening areas of all the through holes. The total opening area a of a through hole is not particularly limited as long as a / b is between 0.01 and 0.5, for example, 0.001 to 0.1 mm. 2 , and 0.001~0.08mm 2 Either of these is acceptable.

[0091] The location of the through-holes in the lid material is not particularly limited, as long as they are not in the sealing area with the resin container described later.

[0092] In this embodiment, when the mass of the fruits and vegetables packaged by the packaging (stored in the storage compartment) is b kg, a / b is 0.01 to 0.5, preferably 0.01 to 0.3, for example, it may be any of 0.01 to 0.15 and 0.01 to 0.1, or any of 0.05 to 0.3 and 0.14 to 0.3, or 0.05 to 0.15. When a / b is above the lower limit, the effect of suppressing swelling in the storage compartment when fruits and vegetables are packaged and stored by the packaging is enhanced. When a / b is below the upper limit, the effect of maintaining the freshness of the fruits and vegetables when they are packaged and stored by the packaging is enhanced.

[0093] The oxygen permeability through the non-opening portion of the lid material, measured in accordance with JIS K 7126-2:2006 under conditions of 23°C and 60% relative humidity, was 100 ml / (m³). 2 It is preferable that the value be less than or equal to 90 ml / (m³). 2 It is more preferable that it be less than or equal to 80 ml / (m³) / day·atm. 2 It is even more preferable that it be less than or equal to (day·atm), for example, 60 ml / (m 2 (day·atm) or less, and 40ml / (m 2 It may be any of the following (day·atm): When the oxygen permeability is less than or equal to the upper limit, the effect of maintaining the freshness of fruits and vegetables when they are packaged and stored in the packaging is further enhanced. The lower limit of the oxygen permeability is not particularly limited. In terms of enabling the packaging to be manufactured at a lower cost, the oxygen permeability is 5 ml / (m³). 2 It is preferable that it is 2000 days or more (atm).

[0094] The oxygen permeability is measured in the area of ​​the lid material where no through-holes are provided. However, the oxygen permeability measured in the resin film before the through-holes are formed may be used as the oxygen permeability of the lid material.

[0095] The amount of oxygen permeation can be adjusted, for example, by adjusting the type and content of the components contained in the lid material (resin film), the a / b ratio of the lid material, and the thickness of the lid material (resin film). For example, since polyolefins typically have high oxygen permeability, the amount of oxygen permeation can be easily reduced by decreasing the polyolefin content in the lid material. On the other hand, since polyester, polyamide, polyvinyl alcohol, etc., generally have low oxygen permeability, the amount of oxygen permeability can be easily reduced by increasing the content of these resins in the lid material.

[0096] <<Manufacturing method for lid material>> The lid material can be manufactured by forming the through-holes in the resin film. Methods for forming through holes in a resin film include, for example, known methods such as piercing the resin film with a needle or irradiating it with a laser.

[0097] A single-layer resin film can be manufactured by known methods, such as melt extrusion molding of a resin composition that will form the resin film. A resin film consisting of multiple layers can be manufactured, for example, by a feed block method in which several extruders are used to melt-extrude the resin composition that will form each layer, a co-extrusion T-die method such as a multi-manifold method, or an air-cooled or water-cooled co-extrusion inflation method. A resin film consisting of multiple layers can be manufactured, for example, by separately preparing two or more films in advance to form two or more of the layers, laminating these two or more films by a dry lamination method using an adhesive solution, and then further laminating other layers as needed to achieve the desired arrangement.

[0098] The resin composition used as the forming material for a single-layer resin film and any of the layers in a multi-layer resin film may be manufactured by adjusting the types and amounts of the constituent components so that the resin film or layer to be formed contains the desired components in the desired amounts. For example, the ratio of the content of components that do not vaporize at room temperature in the resin composition is usually the same as the ratio of the content of those components in the resin film or layer formed from this resin composition.

[0099] Examples of resin compositions for forming the easy-peel layer include compositions for forming an easy-peel layer that include an ethylene polymer, a propylene polymer, and, if necessary, the other components. However, this is just one example. Examples of resin compositions for forming the outer layer include an outer layer forming composition comprising either polyester or polyamide, or both, and optionally the other components. Examples of resin compositions for forming the adhesive layer include adhesive resin, other components as needed, and a solvent as needed. The solvent is a component necessary for preparing the adhesive solution.

[0100] <<Plastic container>> The resin container constituting the packaging body is not particularly limited as long as it has a recess capable of forming a storage compartment within the packaging body and is made of resin. The aforementioned resin container can be manufactured by molding a resin film for its production.

[0101] In this specification, a resin film for manufacturing a resin container is referred to as "resin film for containers." Unless otherwise specified, the term "resin film" refers to the resin film for lids mentioned above, and not to this resin film for containers. The resin container is a molded product of the resin film for containers.

[0102] The resin contained in the aforementioned resin film for the container may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0103] The resin film for the container may consist of a single layer or of two or more layers. If the resin film consists of multiple layers, these layers may be identical or different from one another.

[0104] The resin film for the container is preferably transparent.

[0105] Regardless of whether the resin film for the container is single-layer or multi-layer, the resin contained in the resin film for the container is the same as the resin contained in the resin film for the lid material described above, namely polyolefins, polystyrene, chlorine-based resins, polyvinyl alcohol, polyvinyl acetate, polyester, polyamide, etc.

[0106] The resin film for containers, whether single-layer or multi-layer, may or may not contain other components (i.e., non-resin components) in addition to resin. The other components contained in the resin film for the container may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose. The other components contained in the resin film for containers are not particularly limited and include those similar to those contained in the resin film for lids described above.

[0107] Regardless of whether the container resin film is single-layer or multi-layer, the ratio of resin content (parts by mass) to the total mass (parts by mass) of the container resin film is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, 95% by mass or more, 97% by mass or more, or 99% by mass or more. When the ratio is above the lower limit, the properties of the container resin film are improved. On the other hand, the aforementioned ratio is 100% by mass or less.

[0108] Regardless of whether the container resin film is single-layer or multi-layer, the ratio of the total content (parts by mass) of polyolefin, polystyrene, chlorine-based resin, polyvinyl alcohol, polyvinyl acetate, polyester, and polyamide to the total mass (parts by mass) of the container resin film is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, 95% by mass or more, 97% by mass or more, or 99% by mass or more. When the ratio is above the lower limit, the properties of the container resin film are improved. On the other hand, the aforementioned ratio is 100% by mass or less.

[0109] Regardless of whether the resin film for the container is single-layer or multi-layer, the thickness of the resin film for the container and the resin container is preferably 100 to 2000 μm, and may be, for example, 100 to 1500 μm or 200 to 1000 μm. When the thickness of the resin film for the container and the resin container is above the lower limit, the strength of the resin container, such as pinhole resistance, is increased, and the rigidity of the packaging is also increased. When the thickness of the resin film for the container and the resin container is below the upper limit, excessive thickness of the resin container is avoided. The thickness of the resin film for containers and the resin containers may be adjusted as appropriate depending on the type of resin they contain.

[0110] The volume of the recess in the resin container that serves as the storage area for the packaging is not particularly limited and can be arbitrarily set according to the type and size of the fruits and vegetables to be stored (packaged). Typically, the volume is 300,000 to 4,000,000 mm³. 3 Preferably, it is 300,000 to 2,500,000 mm. 3 , and 300,000 to 1,000,000 mm 3 It could be either of these, or 800,000 to 4,000,000 mm 3 , and 3,000,000 to 4,000,000 mm 3 It could be either of these, or 800,000 to 2,500,000 mm 3 This may also be the case. However, these are just examples of the aforementioned volumes.

[0111] The shape of the recess in the resin container that serves as the storage area for the packaging is not particularly limited and can be arbitrarily set according to the type and size of the fruits and vegetables to be stored (packaged). The shape of the recess may include, but is not limited to, a rectangular parallelepiped, a cubic shape, or a truncated square pyramidal shape.

[0112] <<Manufacturing method for resin containers>> Resin containers can be manufactured by molding a resin film for containers using methods such as heat molding. The resin film for containers can be manufactured in the same manner as the resin film for lids described above.

[0113] The heat molding of resin films for containers can be carried out by known methods. The conditions for heat molding can be adjusted as appropriate depending on the heat molding method or the composition of the resin film for the container. For example, in the case of pressure molding, the molding temperature during heat molding is preferably 90 to 150°C, and the molding time is preferably 1 to 5 seconds. In the case of vacuum molding, it is preferable to indirectly heat the resin film for the container by setting the heating plate temperature to approximately 600°C and the heating time to 5 to 20 seconds.

[0114] <<Manufacturing method for packaging>> The packaging body of this embodiment can be manufactured in the same way as conventional packaging bodies, except that, as described above, the lid material is provided with through-holes with an opening area within a specific range, and the ratio a / b, defined by the total opening area a of the through-holes and the mass b of the produce to be packaged, is within a specific range.

[0115] For example, by placing fruits and vegetables in a recess in a resin container and heat-sealing the resin container and lid material to form a storage compartment, a package containing the fruits and vegetables can be obtained. The sealing temperature when heat-sealing the resin container and lid material is preferably 120 to 180°C, the sealing pressure is preferably 0.05 to 0.5 MPa, and the sealing time is preferably 0.5 to 4 seconds.

[0116] <An example of a preferred packaging> A preferred example of packaging in this embodiment is a packaging in which a resin container and a lid made of resin film are sealed together, and fresh produce is packaged in it. The aforementioned lid material has an opening area of ​​1 × 10 -5 ~0.1mm 2 One or more through holes are provided, The total opening area of ​​the through-holes in the lid material is a mm 2 Assuming the mass of the produce is b kg, a / b is 0.01 to 0.5. The oxygen permeability through the non-opening portion of the lid material, measured in accordance with JIS K 7126-2:2006 under conditions of 23°C and 60% relative humidity, was 100 ml / (m³). 2 (•day•atm) is less than or equal to the above. The aforementioned resin film comprises a layer mainly composed of polyester or polyamide. The thickness of the aforementioned lid material is 30 to 80 μm. An example of a packaging body is one in which the resin container is a molded body of a resin film for containers containing one or more selected from the group consisting of polyolefins and polyesters.

[0117] Another example of a preferred packaging of this embodiment is a packaging in which a resin container and a lid made of resin film are sealed together, and fruits and vegetables are packaged in it. The aforementioned lid material has an opening area of ​​1 × 10 -5 ~0.1mm 2 One or more through holes are provided, The total opening area of ​​the through-holes in the lid material is a mm 2 Assuming the mass of the produce is b kg, a / b is 0.01 to 0.5. The aforementioned resin film comprises an easy-peel layer and an outer layer. The aforementioned easy-peel layer contains two incompatible polyolefins, namely an ethylene-based polymer and a propylene-based polymer. The outer layer comprises one or more materials selected from the group consisting of polyester and polyamide. An example of a packaging body is one in which the resin container is a molded body of a resin film for containers containing one or more selected from the group consisting of polyolefins and polyesters. [Examples]

[0118] The present invention will be described in more detail below with reference to specific examples. However, the present invention is not limited in any way to the examples shown below.

[0119] The resin films used in each example or comparative example to form the lid material or resin container are as follows: PET film (1): Biaxially oriented polyethylene terephthalate film (Toyobo Co., Ltd. "Toyobo Ester E5200", thickness 12 μm) PET film (2): Polyethylene terephthalate film (RP Topla Co., Ltd. "NOA CRYSTAL-V", 400 μm thick) PP film: Polypropylene film (Sumitomo Bakelite Co., Ltd. "Sumilight CEL-R120G", 800 μm thick) Ny film: Biaxially oriented nylon film (Toyobo Co., Ltd. "Harden N1202", 15 μm thick) EP film (1): Easy-peel film for polyethylene terephthalate containers (DIC Corporation "E7800TT", 30 μm thickness) EP film (2): Easy-peel film for polypropylene containers (Toray Film Processing Co., Ltd. "CF Film 9501K2", 30 μm thick, film exhibiting cohesive release properties)

[0120] <<Manufacturing of packaging>> [Example 1] <Manufacturing of lid materials> The EP film (1) and the PET film (1) were bonded together by a dry lamination method using an adhesive (Mitsui Chemicals Laminate Adhesive (2-component type), Takelac A-606 (polyol component) / Takenate A-10 (isocyanate component)), thereby creating a laminated film in which an easy-peel layer, an adhesive layer, and an outer layer are laminated in this order in the thickness direction. By irradiating the laminated film with a pulsed laser, through-holes with a diameter of 70 μm were formed in a single row in the winding direction (MD: Machine Direction) of the laminated film, at intervals of one hole per package, as described later. At this time, the opening area of ​​five of these through holes was measured using a microscope (Keyence VH-6300), and the diameter of the through hole was calculated from the measured value assuming that the shape of the opening was a perfect circle. The average of these five calculated values ​​was adopted as the diameter mentioned above. This procedure was also followed in the other embodiments and comparative examples that follow. Therefore, the opening area is 0.0038 mm². 2 One through-hole is provided, and the total opening area of ​​the through-hole (=a) is 0.0038 mm². 2 A lid material (approximately 42 μm thick) was manufactured.

[0121] <Manufacturing of plastic containers> Using a molding machine, the PET film (2) was indirectly heated by setting the heating plate temperature to 600°C and the heating time to 8 seconds, and then vacuum-formed to produce a resin container with a storage compartment size of 100mm x 100mm x 43mm and a flat, strip-shaped edge around the opening.

[0122] <Manufacturing of packaging materials> Cut pine (0.1 kg) was placed in the storage compartment of the resin container obtained above, and the lid material obtained above was overlapped with the edge of the opening of the resin container. This overlapping portion was heat-sealed under the conditions of a sealing temperature of 160°C, a sealing pressure of 0.2 MPa, and a sealing time of 2 seconds. At this time, the easy-peel layer inside the lid material was in contact with the edge of the opening of the resin container. Based on the above, a package with an a / b ratio of 0.038 was manufactured.

[0123] [Example 2] <Manufacturing of lid materials> Using the same laminated film as in Example 1, a pulsed laser was irradiated under the same conditions as in Example 1 to form through-holes with a diameter of 70 μm in a single row in the winding direction (MD) of the laminated film, at intervals of 5 holes per package, as described later. Therefore, the opening area is 0.0038 mm². 2 Five through holes are provided, and the total opening area of ​​the through holes (=a) is 0.0192 mm². 2A lid material (approximately 42 μm thick) was manufactured.

[0124] <Manufacturing of plastic containers> Using a molding machine, the PET film (2) was indirectly heated by setting the heating plate temperature to 600°C and the heating time to 8 seconds, and then vacuum-formed to produce a resin container with a storage compartment size of 220mm x 220mm x 43mm and a flat, strip-shaped edge at the opening.

[0125] <Manufacturing of packaging materials> Using the lid material and resin container obtained above, a package was manufactured in the same manner as in Example 1, except that cut pineapple (0.5 kg (=b)) was stored in the storage compartment of the resin container, with a / b being 0.038.

[0126] [Example 3] <Manufacturing of lid materials> The EP film (2) and the Ny film were bonded together by a dry lamination method using an adhesive (Mitsui Chemicals Laminate Adhesive (2-component type), Takelac A-606 (polyol component) / Takenate A-10 (isocyanate component)), thereby creating a laminated film in which an easy-peel layer, an adhesive layer, and an outer layer are laminated in this order in the thickness direction. By irradiating the laminated film with a pulsed laser under the same conditions as in Example 1, through holes with a diameter of 70 μm were formed in a single row in the winding direction (MD) of the laminated film, at intervals of four holes per package, as described later. Therefore, the opening area is 0.0038 mm². 2 Four through holes are provided, and the total opening area of ​​the through holes (=a) is 0.0154 mm². 2 A lid material (approximately 45 μm thick) was manufactured.

[0127] <Manufacturing of plastic containers> Using a molding machine, the PP film was indirectly heated by setting the heating plate temperature to 600°C and the heating time to 15 seconds, and then vacuum-formed to produce a resin container with a storage compartment size of 130mm x 170mm x 32mm and a flat, strip-shaped edge around the opening.

[0128] <Manufacturing of packaging materials> Using the lid material and resin container obtained above, a package was manufactured in the same manner as in Example 1, except that cut cabbage and cut broccoli (total 0.1 kg (=b)) were stored in the storage compartment of the resin container, with a / b being 0.154. At this time, the amount of cut cabbage and cut broccoli stored in the storage compartment was adjusted so that the surface area of ​​the cut cabbage and the surface area of ​​the cut broccoli were roughly equal by visual estimation, by looking down at them from above.

[0129] [Example 4] <Manufacturing of lid materials> By irradiating the same laminated film as in Example 3 with a pulsed laser, through-holes with a diameter of 140 μm were formed in a single row in the winding direction (MD) of the laminated film, at intervals of four holes per package, as described later. Therefore, the opening area is 0.0154 mm². 2 Four through holes are provided, and the total opening area of ​​the through holes (=a) is 0.0616 mm². 2 A lid material (approximately 45 μm thick) was manufactured.

[0130] <Manufacturing of plastic containers> Using a molding machine, the PP film was indirectly heated by setting the heating plate temperature to 600°C and the heating time to 15 seconds, and then vacuum-formed to produce a resin container with a storage compartment size of 280mm x 370mm x 32mm and a flat, strip-shaped edge around the opening.

[0131] <Manufacturing of packaging materials> Using the lid material and resin container obtained above, a package was manufactured in the same manner as in Example 3, except that cut cabbage and cut broccoli (total 0.5 kg (=b)) were stored in the storage compartment of the resin container, resulting in a package with a / b of 0.123.

[0132] [Comparative Example 1] <Manufacturing of lid materials> By irradiating the same laminated film as in Example 3 with a pulsed laser, through-holes with a diameter of 70 μm were formed in a single row in the winding direction (MD) of the laminated film, at intervals of one hole per package, as described later. Therefore, the opening area is 0.0038 mm². 2 One through-hole is provided, and the total opening area of ​​the through-hole (=a) is 0.0038 mm². 2 A lid material (approximately 45 μm thick) was manufactured.

[0133] <Manufacturing of packaging materials> Except for using the lid material obtained above, a package with a / b = 0.008 was manufactured in the same manner as in Example 4.

[0134] [Comparative Example 2] <Manufacturing of packaging materials> A package was manufactured in the same manner as in Example 1, except that the same resin container as in Example 2 was used, and cut pineapple (0.5 kg (=b)) was stored in the storage compartment of the resin container, resulting in a package with a / b of 0.008.

[0135] [Comparative Example 3] <Manufacturing of packaging materials> A package was manufactured in the same manner as in Example 4, except that the same resin container as in Example 3 was used, and cut cabbage and cut broccoli (totaling 0.1 kg (=b)) were stored in the storage compartment of the resin container, resulting in a package with a / b of 0.616.

[0136] [Comparative Example 4] <Manufacturing of lid materials> By irradiating the same laminated film as in Example 1 with a pulsed laser, through-holes with a diameter of 140 μm were formed in a single row in the winding direction (MD) of the laminated film, at intervals of four holes per package, as described later. Therefore, the opening area is 0.0154 mm². 2 Four through holes are provided, and the total opening area of ​​the through holes (=a) is 0.0616 mm². 2 A lid material (approximately 42 μm thick) was manufactured.

[0137] <Manufacturing of packaging materials> Except for using the lid material obtained above, a package with a / b = 0.616 was manufactured in the same manner as in Example 1.

[0138] <<Evaluation of packaging>> <Measurement of oxygen permeability in the non-opening portion of the lid material> For the lid material obtained above, the oxygen permeability in the non-opening portion was measured in accordance with JIS K 7126-2:2006, under conditions of a temperature of 23°C and a relative humidity of 60%. The results are shown in Tables 1 and 2 as "Oxygen permeability of lid material (ml / (m)". 2 This is shown in the "day / atm)" column.

[0139] <Evaluation of the effect of suppressing bulging in the storage area> The packaging materials of each example and comparative example obtained above were stored in a refrigerator at a temperature of 10°C for 5 days. Next, the packaging materials were removed from the refrigerator and immediately at room temperature, the point where the height of the lid material from the heat-sealed portion to the resin container (the portion in contact with the edge of the opening of the resin container) was maximized was identified. This height (maximum height) was adopted as the amount of bulging in the storage area, and the effect of suppressing bulging in the storage area was evaluated according to the following criteria. The results are shown in Tables 1 and 2. [Evaluation Criteria] A: The amount of bulging in the storage area is less than 5 mm, indicating that the bulging suppression effect in the storage area is observed. B: The amount of bulging in the storage area is 5 mm or more, and no effect in suppressing the bulging of the storage area is observed.

[0140] <Evaluation of the freshness-preserving effect of fruits and vegetables> After evaluating the effect of suppressing swelling in the storage compartment as described above, the lid was peeled off the resin container and the package was opened. Sensory evaluation was then conducted on the presence or absence of six items: discoloration, water sloshing, softening, spoilage, wilting, and odor of the fresh produce (cut pineapple). "Water sloshing" is a phenomenon in which moisture seeps out onto the surface of the fresh produce, forming droplets, and is a sign of deterioration in the quality of the produce. The effect of maintaining the freshness of the produce was then evaluated according to the following criteria. The results are shown in Tables 1 and 2. If any of the above six items were observed, that item is also shown as a failing item in Tables 1 and 2. [Evaluation Criteria] A: None of the six items were found to be problematic, indicating a high effectiveness in maintaining the freshness of fruits and vegetables. B: One or more of the six items were found, indicating no or very little effect on maintaining the freshness of fruits and vegetables.

[0141] In Tables 1 and 2, the layers made of PET film (1), Ny film, EP film (1), and EP film (2) within the lid material are referred to as "PET layer (1)," "Ny layer," "EP layer (1)," and "EP layer (2)," respectively. PET layer (1) and Ny layer correspond to the outer layers. Similarly, in Tables 1 and 2, the layer made of the PET film (2) and the layer made of the PP film in the resin container are referred to as "PET layer (2)" and "PP layer," respectively.

[0142] [Table 1]

[0143] [Table 2]

[0144] As is clear from the results above, in Examples 1 to 4, the freshness of the produce was maintained when the produce was packaged and stored, and furthermore, the amount of bulging in the storage area was 0 mm, indicating that bulging in the storage area was suppressed. In Examples 1 to 4, the lid material has one or more (1 to 5) through holes, and the opening area a of each through hole is 0.0038 to 0.0154 mm². 2 The mass b of the produce was 0.1 to 0.5 kg, and the ratio a / b was 0.038 to 0.154.

[0145] In Examples 1-4, the oxygen permeability in the non-open portion of the lid material was 65.8 ml / (m²). 2 ·day · atm) or less (29.4~65.8ml / (m 2 It was ·day·atm)).

[0146] In contrast, in Comparative Examples 1 and 2, when fruits and vegetables were packaged and stored, the amount of bulging in the storage area was 7 mm or more, indicating that the bulging of the storage area was not suppressed. In Comparative Examples 1 and 2, through holes were provided in the lid material, but the a / b ratio was 0.008, which was too small. Furthermore, in Comparative Example 1, the freshness of the fruits and vegetables was not maintained.

[0147] In Comparative Examples 3 and 4, although swelling of the storage compartment was suppressed when fruits and vegetables were packaged and stored, the freshness of the fruits and vegetables was not maintained. In Comparative Examples 3 and 4, through holes were provided in the lid material, but the a / b ratio was 0.616, which was too large. Furthermore, Comparative Example 3 was less effective at maintaining the freshness of fruits and vegetables than Comparative Example 4. [Industrial applicability]

[0148] This invention can be used in packaging for fruits and vegetables. [Explanation of symbols]

[0149] 1...Packaging body, 1a...Storage compartment for packaging body 11...Lid material 12. Plastic containers 110... Through hole 111...Sealant layer 112...adhesive layer 113···Outer layer 9···Green fruit

Claims

1. A package containing fresh produce, sealed with a resin container and a lid made of resin film, The aforementioned lid material has an opening area of ​​1 × 10 －５ ~0.1 mm ２ One or more through holes are provided, The total opening area of ​​the through-holes in the lid material is a mm ２ A packaging body in which, when the mass of the produce is b kg, a / b is 0.01 to 0.

5.

2. The oxygen permeability through the non-opening portion of the lid material, measured in accordance with JIS K 7126-2:2006 under conditions of 23°C and 60% relative humidity, was 100 ml / (m³). ２ The packaging according to claim 1, wherein the temperature is less than or equal to (day / atm).

3. The packaging according to claim 1 or 2, wherein the resin film comprises a layer mainly composed of polyester or polyamide.

4. The packaging according to claim 1 or 2, wherein the thickness of the lid material is 30 to 80 μm.

5. The packaging according to claim 1 or 2, wherein the aforementioned produce is cut vegetables or cut fruit.

Images