Packaging bag

Abstract

To provide a packaging bag with excellent oxygen and anti-fogging barrier properties, minimal rollback at openings, and superior transparency, while lowering manufacturing costs compared to bags made from unstretched nylon.SOLUTION: The packaging bag is obtained by cutting and forming a resin film. The resin film contains biaxially oriented nylon and the thickness of the resin film is 10 μm or more and 20 μm or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a packaging bag.

Background Art

[0002] For storing and preserving an object, various storage packages are used. For example, when the object to be stored is something to be orally ingested such as food, it is required that the object can be stored while maintaining good quality, and a package for achieving such an object is disclosed (see Patent Document 1).

[0003] For example, packaging materials used for packaging root vegetables such as potatoes are required to have an oxygen barrier property that prevents oxygen permeation from the viewpoint of ensuring the quality such as the taste and freshness of food.

[0004] In addition, when the content is stored in a packaging bag, fogging or condensation may occur inside the packaging bag due to the moisture of the content, which may impair the appearance. For example, as a packaging bag for fresh produce, there is one described in Patent Document 2. Patent Document 2 describes a multilayer film using a thermoplastic resin porous film layer having pores, and discloses that anti-fogging property is imparted to the surface of the multilayer film.

[0005] Examples of the material of the resin film constituting the packaging bag excellent in oxygen barrier property and anti-fogging property include nylon. So far, unstretched nylon, which is particularly excellent in bag breakage resistance among nylons, has been used.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in recent years, there has been a problem of insufficient supply of undrawn nylon, and the development of substitutes has been desired. In addition, undrawn nylon has problems of high cost and insufficient transparency.

[0008] In addition, the packaging bag may be used by containing the contents and twisting the opening of the packaging bag. However, when the packaging bag is constituted by using a resin film having high rigidity, there has been a problem that the opening is rewound over time.

[0009] The present invention has been made in view of the above circumstances, and an object thereof is to provide a packaging bag excellent in oxygen barrier properties and antifogging properties, having less rewinding of the opening, capable of being manufactured at a lower cost than when using undrawn nylon, and having excellent transparency.

Means for Solving the Problems

[0010] In order to solve the above problems, the present invention adopts the following configuration. [1]. A packaging bag obtained by heat-sealing and bag-making a resin film, wherein the resin film contains biaxially stretched nylon, and the thickness of the resin film is 10 μm or more and 20 μm or less. [2]. The packaging bag according to [1], wherein the resin film is a single-layer film. [3]. The packaging bag according to [1] or [2], which is a bag for packaging fresh fruits and vegetables and is used by twisting the opening of the packaging bag. [4]. The packaging bag according to any one of [1] to [3], wherein the ratio of the content of the biaxially stretched nylon to the total mass of the resin film in the resin film is 90% by mass or more. [5]. The packaging bag according to any one of [1] to [4], wherein the biaxially stretched nylon is one or more selected from the group consisting of 6-nylon, 66-nylon, and a copolymer of 6-nylon and 66-nylon. The packaging bag according to any one of [1] to [5], wherein the haze of the resin film, measured in accordance with JIS K 7136:2000, is 8% or less. The packaging bag according to any one of [1] to [6], wherein the tensile elastic modulus of the resin film, measured in accordance with JIS K 7162, is 1000 MPa or more and 3000 MPa or less. [8]. The water vapor permeability of the resin film, measured in accordance with JIS Z 0208, is 150 g / m 2 ·day or more, and the packaging bag according to any one of [1] to [7]. [9]. The oxygen transmission rate of the resin film, measured in accordance with JIS K 7126-2:2006, is 200 ml / (m 2 ·day·atm) or less, and the packaging bag according to any one of [1] to [8].

Advantages of the Invention

[0011] According to the present invention, there is provided a packaging bag that is excellent in oxygen barrier properties and antifogging properties, has little rewinding at the opening, can be manufactured at a lower cost than in the case of using unstretched nylon, and is excellent in transparency.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0013] <<Resin Film>> The packaging bag according to an embodiment of the present invention is a packaging bag obtained by fusing and bag-making a resin film, wherein the resin film contains biaxially stretched nylon, and the thickness of the resin film is 10 μm or more and 20 μm or less.

[0014] Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the drawings used in the following description may schematically show an enlarged view of the main part for the sake of easy understanding of the features of the present invention, and the dimensional ratios of each component are not necessarily the same as the actual ones.

[0015] FIG. 1 is a cross-sectional view schematically showing an example of the resin film constituting the packaging bag of the present embodiment.

[0016] The resin film 1 contains biaxially stretched nylon. By including biaxially stretched nylon in the resin film 1, the oxygen barrier property and antifogging property of the resin film 1 can be improved. In addition, since biaxially stretched nylon is less expensive than unstretched nylon, the resin film 1 can be manufactured at a lower cost than when unstretched nylon is used. Furthermore, since biaxially stretched nylon has higher transparency than unstretched nylon, the transparency of the resin film 1 can be improved compared to the case where unstretched nylon is used.

[0017] Examples of the biaxially stretched nylon include nylon obtained by polymerizing or copolymerizing a cyclic lactam (lactam having 3 or more ring members), an amino acid, or a nylon salt obtained by reacting a diamine and a dicarboxylic acid, and then subjecting it to a biaxial stretching treatment.

[0018] Examples of the cyclic lactam include ε-caprolactam, ω-enanthlactam, ω-laurolactam, α-pyrrolidone, α-piperidone, and the like.

[0019] Examples of the amino acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and the like.

[0020] Examples of the diamine for forming the nylon salt include aliphatic amines such as tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine; alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, isophoronediamine, piperazine, bis(4-aminocyclohexyl)methane, and 2,2-bis-(4-aminocyclohexyl)propane, and the like.

[0021] Examples of the dicarboxylic acid for forming the nylon salt include aliphatic dicarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid; alicyclic carboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, and the like.

[0022] As the biaxially stretched nylon, more specifically, for example, 4-nylon, 6-nylon, 7-nylon, 11-nylon, 12-nylon, 46-nylon, 66-nylon, 69-nylon, 610-nylon, 611-nylon, 612-nylon, 6T-nylon, 6I-nylon, copolymers of 6-nylon and 66-nylon (nylon 6 / 66), copolymers of 6-nylon and 610-nylon, copolymers of 6-nylon and 611-nylon, copolymers of 6-nylon and 12-nylon (nylon 6 / 12), copolymers of 6-nylon and 612-nylon, copolymers of 6-nylon and 6T-nylon, copolymers of 6-nylon and 6I-nylon, copolymers of 6-nylon and 66-nylon and 610-nylon, copolymers of 6-nylon and 66-nylon and 12-nylon (nylon 6 / 66 / 12), copolymers of 6-nylon and 66-nylon and 612-nylon, copolymers of 66-nylon and 6T-nylon, copolymers of 66-nylon and 6I-nylon, copolymers of 6T-nylon and 6I-nylon, copolymers of 66-nylon and 6T-nylon and 6I-nylon, etc. can be mentioned.

[0023] The nylon contained in the resin film 1 may be only one kind or two or more kinds. When there are two or more kinds, their combinations and ratios can be arbitrarily selected according to the purpose.

[0024] In terms of heat resistance, mechanical strength, and ease of availability, etc., the biaxially stretched nylon is preferably one kind or two or more kinds selected from the group consisting of 6-nylon, 12-nylon, 66-nylon, nylon 6 / 66, nylon 6 / 12, and nylon 6 / 66 / 12. More preferably, it is one kind or two or more kinds selected from the group consisting of 6-nylon, 66-nylon, and nylon 6 / 66. From the viewpoint of low cost, 6-nylon is even more preferable.

[0025] The resin film 1 may contain only biaxially oriented nylon (i.e., it may be made of biaxially oriented nylon), or it may contain biaxially oriented nylon and other components (which may be referred to as "other components" in this specification).

[0026] The other components contained in the resin film 1 are not particularly limited and can be arbitrarily selected according to the purpose. For example, they may be either resin components or non-resin components. The other components that are resin components are resins that do not correspond to biaxially oriented nylon (i.e., resins other than biaxially oriented nylon). The other components that are resin components may be homopolymers that are polymers of one type of monomer, or they may be copolymers that are polymers of two or more types of monomers.

[0027] Examples of the other components that are non-resin components include additives known in the art. Examples of the additives include anti-fogging agents, antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, viscosity reducers, thickeners, heat stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, and the like.

[0028] The other components contained in the resin film 1 may be only one type, or two or more types. When there are two or more types, their combinations and ratios can be arbitrarily selected according to the purpose.

[0029] In the resin film 1, the ratio ([content (parts by mass) of biaxially stretched nylon] / [total mass (parts by mass) of the resin film 1]×100) of the content (parts by mass) of biaxially stretched nylon to the total mass (parts by mass) of the resin film 1 is preferably 90% by mass or more, more preferably 95% by mass or more, and may be, for example, either 97% by mass or more and 99% by mass or more. By the ratio being at least the lower limit value, the oxygen barrier property and antifogging property of the resin film 1 can be further improved, and the resin film 1 can be manufactured at a lower cost. Also, the transparency of the resin film 1 can be further improved. On the other hand, the ratio is 100% by mass or less. The ratio is usually the same as the ratio ([content (parts by mass) of biaxially stretched nylon in the resin composition for forming a resin film]) / [total content (parts by mass) of components that do not vaporize at room temperature in the resin composition for forming a resin film]×100) of the content (parts by mass) of biaxially stretched nylon to the total content (parts by mass) of components that do not vaporize at room temperature in the resin composition for forming a resin film, which will be described later.

[0030] The resin film 1 may be composed of one layer (single layer) or may be composed of two or more layers, but it is preferably composed of one layer (single layer) (a single-layer film). By the resin film 1 being composed of one layer (single layer), the appearance can be further improved and the cost can be further reduced. Also, when the resin film 1 is a laminated film in which a layer containing biaxially stretched nylon and a layer containing an ethylene-vinyl alcohol copolymer (EVOH) are laminated, lumps of resin (which may be referred to as "resin balls" in this specification) may occur at the welded part obtained by fusing the resin films 1 together, and the seal strength of the resin film 1 may decrease. In contrast, by the resin film 1 being composed of one layer (single layer), the generation of resin balls can be further suppressed and the seal strength of the resin film 1 can be further improved. When the resin film 1 is composed of two or more layers, these multiple layers may be the same as or different from each other, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

[0031] The thickness of the resin film 1 is 10 μm or more and 20 μm or less. The thickness of the resin film 1 is more preferably 12 μm or more and 18 μm or less, and even more preferably 13 μm or more and 17 μm or less. When the thickness of the resin film 1 is equal to or greater than the lower limit value, in the packaging bag obtained by using the resin film 1, the storage stability of the packaged product is higher, and the property of stably maintaining the structure of the packaging bag is higher. When the thickness of the resin film 1 is equal to or less than the upper limit value, when the opening of the packaging bag constituted by using the resin film 1 is twisted and used, it is possible to more effectively suppress the opening from rewinding over time. In addition, the moldability of the resin film is further improved. Furthermore, the transparency of the packaging bag constituted by using the resin film is further improved, and it becomes easier to visually recognize the stored items from the outside of the packaging bag. When the resin film 1 is composed of multiple layers, it is preferable that the total thickness of these multiple layers is within the above numerical range.

[0032] It is preferable that all the layers of the resin film 1 have transparency, and the resin film 1 has transparency, that is, the resin film 1 is a transparent resin film. In the packaging bag obtained by using such a resin film 1, the packaged product can be easily visually recognized through the resin film 1.

[0033] [Oxygen transmission rate] The oxygen transmission rate of the resin film measured in accordance with JIS K 7126-2:2006 is, for example, 200 ml / (m 2 ·day·atm) or less, 160 ml / (m 2 ·day·atm) or less, 120 ml / (m 2 ·day·atm) or less, and 80 ml / (m 2 ·day·atm) or less. On the one hand, the oxygen transmission rate of the resin film is 5 ml / (m 2 ·day·atm) or more. That is, the oxygen transmission rate of the resin film may be any one of 5 to 200 ml / (m 2 ·day·atm), 5 to 160 ml / (m 2 ·day·atm), 5 to 120 ml / (m 2 ·day·atm), and 5 to 80 ml / (m 2 ·day·atm). By setting the oxygen transmission rate of the resin film below the upper limit value, it is possible to more effectively suppress the greening, sprouting, and rooting of fruits and vegetables packaged in a packaging bag made of the resin film.

[0034] The oxygen transmission rate of the resin film can be measured, for example, as the oxygen transmission rate per 24 hours under the conditions of a pressure of 1 atm and an atmosphere of 23°C and 60% RH for the resin film.

[0035] The oxygen transmission rate of the resin film can be adjusted by adjusting the type, amount, or thickness of the components contained in any layer constituting the resin film. For example, by adjusting the type and content of the biaxially oriented nylon contained in the resin film, the oxygen transmission rate of the resin film can be easily adjusted.

[0036] [Moisture permeability] The moisture permeability of the resin film measured in accordance with JIS Z 0208 (cup method) is preferably 150 g / m 2 ·day or more, more preferably 150 to 350 g / m 2 ·day, and even more preferably 200 to 300 g / m 2 ·day. By setting the moisture permeability of the resin film above the lower limit value, the anti-fogging property of the resin film can be further improved. By setting the moisture permeability of the resin film below the upper limit value, the water vapor barrier property of the resin film can be further improved.

[0037] The moisture permeability of the resin film can be adjusted by adjusting the type, amount, or thickness of the components contained in any of the layers constituting the resin film. For example, by adjusting the type and content of the biaxially stretched nylon contained in the resin film, the moisture permeability of the resin film can be easily adjusted.

[0038] [Tensile modulus of elasticity] The tensile modulus of elasticity of the resin film measured in accordance with JIS K 7162 is preferably 1000 MPa or more and 3000 MPa or less, more preferably 1100 MPa or more and 2800 MPa or less, and even more preferably 2100 MPa or more and 2700 MPa or less a. When the tensile modulus of elasticity of the resin film is equal to or higher than the lower limit value, it is more effectively suppressed that the resin film becomes overly soft, and it becomes less likely to bend even when the resin film is bundled. When the tensile modulus of elasticity of the resin film is equal to or lower than the upper limit value, the resin film becomes softer, and when the opening of the packaging bag formed using the resin film is twisted and used, the unwinding of the opening is more effectively suppressed.

[0039] The tensile modulus of elasticity of the resin film can be measured, for example, as the tensile modulus of elasticity of the resin film under the conditions of a temperature of 20 °C and a humidity of 50%.

[0040] The tensile modulus of elasticity of the resin film can be adjusted by adjusting the type, amount, or thickness of the components contained in any of the layers constituting the resin film. For example, by adjusting the type and content of the biaxially stretched nylon contained in the resin film, the moisture permeability of the resin film can be easily adjusted.

[0041] [Haze] The haze of the resin film measured in accordance with JIS K 7136:2000 is preferably 8% or less, more preferably 6% or less, and even more preferably 4% or less. When the haze of the resin film is equal to or less than the upper limit value, the transparency of the resin film is further improved, and the stored items can be more clearly visible from the outside of the packaging bag composed of the resin film. The lower limit value of the haze of the resin film is not particularly limited. For example, a resin film with a haze of 0.5% or more can be manufactured more easily, and a resin film with a haze of 3% or more can be manufactured even more easily. In one embodiment, the haze of the resin film may be any of 0.5 to 8%, 0.5 to 6%, 0.5 to 4%, 3 to 8%, 3 to 6%, and 3 to 4%. However, these are examples of the haze of the resin film.

[0042] The haze of the resin film can be adjusted by adjusting the type, amount, or thickness of the components contained in any layer constituting the resin film. For example, the haze of the resin film can be easily adjusted by adjusting the type and content of the biaxially stretched nylon contained in the resin film.

[0043] <<Manufacturing method of resin film>> The resin film constituting the packaging bag of the present embodiment can be manufactured, for example, by melting and extruding a resin composition for forming a resin film, which is a forming material of the resin film, using an extruder and molding it.

[0044] Among the resin films constituting the packaging bag of the present embodiment, a laminated film (a resin film composed of multiple layers) can be manufactured, for example, by a feed block method of melting and extruding resins and resin compositions, etc., which are forming materials of each layer, using several extruders, a coextrusion T-die method such as a multi-manifold method, an air-cooled or water-cooled coextrusion inflation method, etc.

[0045] In addition, the laminated film constituting the packaging bag of the present embodiment can be manufactured by coating a resin, a resin composition, or the like, which is a forming material for any one of the layers therein, on the surface of another layer for constituting the resin film, drying it as necessary, thereby forming a laminated structure in the resin film, and further laminating other layers as required so as to have a desired arrangement form.

[0046] In addition, the laminated film constituting the packaging bag of the present embodiment can be manufactured by separately preparing two or more films in advance for constituting two or more of the layers therein, and laminating these films by using an adhesive by any one of a dry lamination method, an extrusion lamination method, a hot melt lamination method, and a wet lamination method, and further laminating other layers as required so as to have a desired arrangement form.

[0047] In addition, the laminated film constituting the packaging bag of the present embodiment can be manufactured by laminating two or more films prepared separately in advance without using an adhesive by a thermal (heat) lamination method or the like, and further laminating other layers as required so as to have a desired arrangement form.

[0048] When a resin film is manufactured by a coextrusion inflation method or the like, it tends to get wrinkled when left in the air. However, since a resin film manufactured by a coextrusion T-die method tends not to get wrinkled even when left in the air, it is preferable to manufacture the resin film by using the coextrusion T-die method.

[0049] When manufacturing the resin film constituting the packaging bag of the present embodiment, two or more of the forming methods of any one of the layers (films) in the resin film listed so far may be combined.

[0050] Regardless of the manufacturing method, the resin composition that serves as the forming material for any layer in the resin film may be manufactured by adjusting the types and contents of the contained components so that the layer to be formed contains the target components (constituent materials) in the target contents. For example, the ratio of the contents of the components that do not vaporize at room temperature in the resin composition is usually the same as the ratio of the contents of the components in the layer formed from this resin composition.

[0051] As the resin composition (which may be referred to as the "resin composition for forming a resin film" in this specification) for forming the resin film 1 shown in FIG. 1 among the resin films, for example, a resin composition containing the above-mentioned biaxially stretched nylon and, if necessary, the other components may be mentioned.

[0052] <<Packaging bag>> The packaging bag of this embodiment is a packaging bag obtained by heat-sealing and bag-making the above-mentioned resin film. The packaging bag of this embodiment has a welded portion obtained by heat-sealing the above-mentioned resin films together. The packaging bag of this embodiment has an accommodation space formed by adhering a part of a pair of resin films to each other.

[0053] The width of the welded portion of the packaging bag is preferably 300 μm or less. Thereby, even when a plurality of packaging bags are stacked, the portion where the ends are stacked does not become bulky.

[0054] The welded portion of the packaging bag can be identified, for example, by cutting in the cross-sectional direction using a microtome "HM340E manufactured by PHC Corporation" as shown in the principle diagram of the rotary microtome in FIG. 3 and observing with a polarizing microscope "ECLIPSE LV100N POL manufactured by Nikon Solutions Co., Ltd." as shown in the enlarged schematic view of the end portion of the packaging bag in FIG. 3.

[0055] In the packaging bag of this embodiment, the width of the welded portion is the dimension of the welded portion in the direction orthogonal to its longitudinal direction. When the width of the welded portion is not uniform, it is sufficient that the maximum value of the width of the welded portion is 300 μm or less.

[0056] The width of the welded portion is more preferably 280 μm or less, and even more preferably 250 μm or less. When a plurality of packaging bags are stacked, the effect that the overlapped portion of the ends does not bulge can be further improved by the width of the welded portion being below the upper limit value. On the other hand, in terms of ease of production, the width of the welded portion of the packaging bag is preferably 10 μm or more.

[0057] The width of the welded portion can be adjusted by adjusting the type or content of the components contained in any layer constituting the resin film. For example, the width of the welded portion can be easily adjusted by adjusting the type and content of the biaxially stretched nylon contained in the resin film. Further, the width of the welded portion can also be adjusted by adjusting the conditions for fusing and bag-making (formation conditions of the welded portion) of the resin film. For example, when fusing and bag-making the resin film, the width of the welded portion can be easily adjusted by changing the temperature of the fusing blade and the fusing time.

[0058] For example, in terms of being able to easily adjust the width of the welded portion within the above-mentioned range, the temperature of the fusing blade is preferably 410°C to 490°C, more preferably 420°C to 480°C, and even more preferably 430°C to 470°C.

[0059] For example, in terms of being able to easily adjust the width of the welded portion within the above-mentioned range, the fusing time is preferably 270 ms to 390 ms, more preferably 280 ms to 380 ms, and even more preferably 290 ms to 370 ms.

[0060] In addition, since the packaging bag of the present embodiment includes the above-mentioned resin film, the color of the welded portion between the resin films is good.

[0061] Among the packaging bags of the present embodiment, it is preferable that the welded portion has carbide pieces of the resin film. The carbide pieces are generated, for example, by the heat during fusing when fusing and bag-making the resin film. Since the welded part has carbide pieces of the resin film, it becomes easier to pick up the welded part. The fact that the welded part has carbide pieces of the resin film means that part of the carbide pieces can be removed, but not all of them (for example, part of the carbide pieces are on the surface of the welded part and part are inside the welded part).

[0062] The size of the carbide pieces is preferably 50 μm or more and 1000 μm or less, more preferably 55 μm or more and 900 μm or less, and even more preferably 60 μm or more and 800 μm or less. When the size of the carbide pieces is equal to or greater than the lower limit value, the effect that the welded part is more likely to be caught and picked up can be further improved. When the size of the carbide is equal to or less than the upper limit value, it is possible to further suppress the situation where the welded part is caught too much and is difficult to pick up, and it is also possible to further suppress the occurrence of pinholes in the welded part.

[0063] The identification image of the carbide pieces can be obtained, and the maximum value of the length of the line segment connecting any two points located on the contour line in the identification image can be adopted as the size of the carbide pieces. The identification image can be obtained, for example, from the imaging data when observing the welded part with an optical microscope.

[0064] The size of the carbide pieces can be adjusted by adjusting the type or content of the components contained in any layer constituting the resin film. For example, by adjusting the type and content of the biaxially stretched nylon contained in the resin film, the size of the carbide pieces can be easily adjusted. Also, the size of the carbide pieces can be adjusted by adjusting the conditions for fusing and bag-making of the resin film (the formation conditions of the welded part). For example, when fusing and bag-making the resin film, the size of the carbide pieces can be easily adjusted by changing the temperature of the fusing blade.

[0065] For example, in terms of being able to easily adjust the size of the carbide piece within the above-mentioned range, the temperature of the cutting blade is preferably 410°C to 490°C, more preferably 420°C to 480°C, and even more preferably 430°C to 470°C.

[0066] The volume of the accommodation space of the packaging bag is 0.0005 m 3 or more and 0.0030 m 3 or less, preferably 0.0010 m 3 or more and 0.0030 m 3 or less, more preferably 0.0015 m 3 or more and 0.0025 m 3 or less, and even more preferably so.

[0067] FIG. 2 is a cross-sectional view schematically showing an example of the packaging bag of the present embodiment. The packaging bag 10 shown here is formed using the resin film 1 shown in FIG. 1. The packaging bag 10 has an accommodation space S formed by partially adhering a pair of resin films 1 to each other, and is generally configured. An object to be stored (not shown) is stored in the accommodation space S of the packaging bag 10.

[0068] The packaging bag of the present embodiment is not limited to the above-described embodiment, and within the scope not departing from the gist of the present invention, some configurations may be changed, deleted, or added. For example, the packaging bag 10 shown in FIG. 2 uses a pair of the same type of resin films 1, 1, but the packaging bag of the present invention may use a pair of different types of resin films. Also, the packaging bag of the present invention may be provided with other configurations other than the resin film within the range not impairing the effects of the present invention. The other configurations are not particularly limited and may be appropriately selected according to the purpose.

[0069] <<Manufacturing method of the packaging bag>> The packaging bag of the present embodiment can be manufactured by adhering a part of the resin films to each other so as to have an accommodation space using the resin film. The adhesion between resin films can be achieved by applying known heat-sealing bag-making methods. Note that heat-sealing bag-making refers to shaping a bag while melting and sealing resin films with heat.

[0070] <<Method of Using the Packaging Bag>> The packaging bag of this embodiment can be used to package fresh produce by twisting the opening of the packaging bag. Twisting the opening of the packaging bag is for closing the opening of the packaging bag.

[0071] The opening of the package is preferably twisted through the twisted portion to such an extent that oxygen does not flow in and out between the inside and outside of the packaging bag. Specifically, the angle of the twisted portion is preferably 180° or more and 720° or less (0.5 rotation or more and 2.0 rotations or less), more preferably 360° or more and 720° or less (1.0 rotation or more and 2.0 rotations or less), and even more preferably 540° or more and 720° or less (1.5 rotations or more and 2.0 rotations or less).

[0072] Examples of the fresh produce include, for example, large-leaf mustard, spinach, komatsuna, mizuna, mibuna, asparagus, Chinese cabbage, lettuce, thyme, sage, parsley, Italian parsley, rosemary, oregano, lemon balm, chive, lavender, salad burnet, ramsons, rocket, dandelion, sunflower, basil, arugula, cress, moringa, celery, kale, leek, cabbage, Chinese cabbage, shungiku, salad turnip, sanchu, butterbur, turnip, Chinese chives, clover, celery, mekabu, broccoli, cauliflower, myoga, daikon radish, carrot, burdock, radish, kabocha, potato, sweet potato, yam, taro, colocasia, arrowroot, yamato potato, mandarin orange, pepper, paprika, shishito pepper, cucumber, eggplant, tomato, cherry tomato, pumpkin, bitter gourd, okra, sweet corn, edamame, green bean, wax bean, broad bean, shiitake mushroom and other mushroom fungi. Among these, sweet potato, potato, taro, mandarin orange, shiitake mushroom, carrot, etc. are preferred, and potato is more preferred.

[0073] The amount of fresh fruits and vegetables packed in the packaging bag is preferably 100 g or more and 900 g or less, more preferably 150 g or more and 850 g or less, and even more preferably 200 g or more and 800 g or less per 0.002 m 3 of the volume of the storage space of the packaging bag.

Examples

[0074] Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the examples shown below at all.

[0075] [Example 1] [[Manufacture of Resin Film]] A resin film having the configuration shown in FIG. 1 was manufactured according to the procedure shown below.

[0076] As the resin constituting the resin film, biaxially oriented nylon (ONy, "Emblem" manufactured by Unitika Ltd.) was prepared.

[0077] The temperature of the die was set at 260°C, and the ONy was melt-extruded and molded to obtain a resin film (thickness: 15 μm).

[0078] [[Evaluation of Resin Film]] [[Measurement of Oxygen Permeation Rate]] For the above resin film, the oxygen permeation rate under the conditions of a temperature of 23°C and a relative humidity (RH) of 60% was measured in accordance with JIS K 7126-2:2006. The results are shown in Table 1.

[0079] [[Measurement of Water Vapor Permeability]] For the above resin film, the water vapor permeability was measured in accordance with JIS Z 0208 (cup method). The results are shown in Table 1.

[0080] [[Measurement of Tensile Elastic Modulus]] For the above resin film, the tensile elastic modulus under the conditions of a temperature of 20°C and a humidity of 50% was measured in accordance with JIS K 7162. The results are shown in Table 1.

[0081] <Measurement of haze> For the above resin film, the haze (%) was measured in accordance with JIS K 7136:2000. The results are shown in Table 1.

[0082] <<Manufacture of packaging bag>> For the above resin film, a packaging bag with a storage space formed by fusing the resin films together with a part of them adhered was produced using a fusing bag-making machine (temperature of the fusing blade: 460 °C, fusing time: 280 ms). The volume of the storage space of the packaging bag was 0.002 m 3 It was.

[0083] Using a microtome "HM340E manufactured by PHC Corporation", the welded part of the package was cut in the cross-sectional direction and observed with a polarized light microscope "ECLIPSE LV100N POL manufactured by Nikon Solutions Co., Ltd.", and the width of the welded part of the package was measured to be 40 μm.

[0084] <<Evaluation of packaging bag>> <Freshness retention performance> Using the above packaging bag, each of taro (500 g), potato 1 (Makein, 500 g), potato 2 (Baron, 500 g), mandarin orange (1000 g), sweet potato 1 (Beniharuka, 500 g), sweet potato 2 (Naruto Gold, 500 g), shiitake mushroom 1 (10 °C, 200 g), and shiitake mushroom 2 (20 °C, 200 g) was packaged, and the opening was each twisted 540° (3 rotations). Stored in this state for 5 days, and in accordance with the following criteria, the freshness retention status was visually confirmed. The results are shown in Table 1. (Evaluation criteria) A: The freshness is well maintained. B: The freshness is not well maintained.

[0085] <Anti-fogging property> For the above packaging bag, it was stored statically at 5 °C for 60 minutes. Then, the packaged bag after this storage was visually observed from the outside, the visibility of the above stored items was confirmed, and the anti-fogging property in the packaging bag was evaluated in accordance with the following criteria. The results are shown in Table 1. (Evaluation Criteria) A: No fogging is observed on the packaging bag, and the entire stored item can be clearly visually recognized. B: Slight fogging is observed on the packaging bag, but the entire stored item can be visually recognized. C: Severe fogging is observed on the packaging bag, and at least a part of the stored item cannot be visually recognized.

[0086] <Unwinding of the Opening> Regarding the above packaging bag, the opening was twisted 540° (three rotations). After 9 days, the packaging bag was cut with scissors and the cross-section was visually confirmed, and the angle of the twisted part was measured to evaluate the unwinding situation of the opening according to the following criteria. The results are shown in Table 1. (Evaluation Criteria) A: The angle of the twisted part after 5 days exceeds 360°, and the unwinding of the opening is small. B: The angle of the twisted part after 5 days is 360° or less, and the unwinding of the opening is large.

[0087] <Bag Burst Resistance> Regarding 10 bags of the above packaging bag (500 g / bag), a drop test was carried out in accordance with JIS Z 0202, and the number of packaging bags that burst was visually confirmed, and the bag burst resistance was evaluated according to the following criteria. The results are shown in Table 1. (Evaluation Criteria) A: The number of packaging bags that burst is 1 or less. B: The number of packaging bags that burst is 2 or more.

[0088] [Comparative Example 1] As the resin constituting the resin film, except that unstretched nylon (CNy, "Leofil" manufactured by Toray Industries, Inc.) was used instead of ONy, this resin film was evaluated in the same manner as in Example 1. Also, a packaging bag was manufactured in the same manner as in Example 1, and this packaging bag was evaluated. The results are shown in Table 1.

[0089] [Comparative Example 2] The resin film was evaluated in the same manner as in Example 1, except that the thickness of the resin film was changed to 25 μm instead of 15 μm. Also, a packaging bag was manufactured in the same manner as in Example 1, and this packaging bag was evaluated. The results are shown in Table 1.

[0090] [Comparative Example 3] The resin film was evaluated in the same manner as in Example 1, except that biaxially oriented polypropylene (OPP, "AF642" manufactured by Futamura Chemical Co., Ltd.) was used instead of ONy as the resin constituting the resin film. Also, a packaging bag was manufactured in the same manner as in Example 1, and this packaging bag was evaluated. The results are shown in Table 1.

[0091] [Table 1]

[0092] As is clear from the above results, in Example 1, since the constituent material of the resin film was ONy, it could be manufactured at a lower cost than Comparative Example 1 (constituent material: CNy). In Example 1, since the oxygen permeability of the resin film was as low as 30 ml / (m 2 ·day·atm), the freshness retention performance of the packaging bag was better than that of Comparative Example 3 (oxygen permeability: 1000 ml / (m 2 ·day·atm)). In Example 1, since the moisture permeability of the resin film was as high as 250 g / (m 2 ·day), the anti-fogging property of the packaging bag was better than that of Comparative Example 3 (moisture permeability: 5 g / (m 2 ·day)). In Example 1, although the tensile elastic modulus of the resin film was as high as 2400 MPa, since the thickness of the resin film was as thin as 15 μm, the rewinding of the opening of the packaging bag was less than that of Comparative Example 2. In Example 1, since the haze of the resin film was as low as 4%, the transparency of the packaging bag was better than that of Comparative Example 1 (haze: 6%). In Example 1 and Comparative Examples 1 to 3, the bag break resistance of the packaging bag was good in all cases.

Industrial Applicability

[0093] The present invention can be used in the production of packaging bags that are excellent in oxygen barrier properties and antifogging properties, have little rewinding of the opening, can be produced at a lower cost than when using unstretched nylon, and are excellent in transparency.

Explanation of Signs

[0094] 1... Resin film 10... Packaging bag S... Accommodation space of the packaging bag

Claims

1. A packaging bag obtained by heat-sealing and bag-making a resin film, wherein the resin film contains biaxially oriented nylon, and the thickness of the resin film is 10 μm or more and 20 μm or less. The packaging bag.

2. The packaging bag according to Claim 1, wherein the resin film is a single-layer film.

3. The packaging bag according to Claim 1 or 2, which is a bag for packaging fresh fruits and vegetables and is used by twisting the opening of the packaging bag.

4. The packaging bag according to Claim 1 or 2, wherein the proportion of the content of the biaxially oriented nylon in the total mass of the resin film is 90% by mass or more.

5. The packaging bag according to Claim 1 or 2, wherein the biaxially oriented nylon is one or more selected from the group consisting of 6-nylon, 66-nylon, and a copolymer of 6-nylon and 66-nylon.

6. The packaging bag according to Claim 1 or 2, wherein the haze of the resin film measured in accordance with JIS K 7136:2000 is 8% or less.

7. The packaging bag according to Claim 1 or 2, wherein the tensile modulus of the resin film measured in accordance with JIS K 7162 is 1000 MPa or more and 3000 MPa or less.

8. The water vapor permeability of the resin film measured in accordance with JIS Z 0208 is 150 g / m ２ ・day or more, and the packaging bag according to claim 1 or 2.

9. The oxygen transmission rate of the resin film, measured in accordance with JIS K 7126-2:2006, is 200 ml / (m ２ ·day·atm) or less, the packaging bag according to claim 1 or 2.

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