Packaging bags, freshness-preserving bags for fruits and vegetables, packaged bodies containing fruits and vegetables, and methods for preserving the freshness of fruits and vegetables.

Abstract

This invention provides a technology for packaging bags that can suppress deformation of the through-slit (S). [Solution] The packaging bag 100 of the present invention has a main body 10 for containing contents and an opening 20 for putting in and taking out the contents, wherein the main body 10 is made of a synthetic resin film, and the main body 20 has through slits (S), and when the direction in which the opening 20 widens is defined as the transverse direction and the direction perpendicular to the transverse direction is defined as the vertical direction, the through slits (S) have both a through slit (Sa) that is not parallel to the vertical direction and a through slit (Sb) that is not parallel to the transverse direction (however, the through slits (Sa) and the through slits (Sb) may be the same or different).

Description

[Technical Field]

[0001] The present invention relates to packaging bags, freshness-preserving bags for fruits and vegetables, packaged bodies containing fruits and vegetables, and methods for preserving the freshness of fruits and vegetables. [Background technology]

[0002] Vegetables, fruits, and other fresh produce continue to respire even after harvesting. Therefore, during storage, distribution, or preservation after harvest, the produce consumes energy through its own respiration, leading to deterioration of freshness. To maintain the freshness of fresh produce, methods are known that moderately suppress respiration. Packaging bags used for this purpose are known as MA (Modified Atmosphere) packaging.

[0003] For example, Patent Document 1 discloses a freshness preservation bag that uses a rotating device to which a perforating needle of a predetermined shape is attached and a roller for transporting polyolefin film, wherein the perforating needle is pierced through the transported polyolefin film by the rotation of the rotating device, thereby creating a predetermined through-slit-shaped perforation. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-134939 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, conventional packaging bags made of synthetic film resin with through-slits, as described in Patent Document 1, have a problem in that the weight of the contents is added to the bag body due to tension generated when the contents are placed inside, as well as vibrations during storage and transportation, causing the through-slits in the bag body to deform. [Means for solving the problem]

[0006] The inventors of the present invention conducted thorough research on suppressing changes in the shape of through-slits in packaging bags made of synthetic resin film, and found that controlling the orientation and shape of the through-slits is effective, thus completing the present invention. According to the present invention, the following packaging bags and related technologies are provided.

[0007] [1] The main body that houses the contents, An opening for inserting and removing the contents, A packaging bag having the main body made of synthetic resin film, The main body portion has a through slit (S), When the direction in which the opening widens is defined as the horizontal direction, and the direction perpendicular to the horizontal direction is defined as the vertical direction, The through-slit (S) includes both a through-slit (Sa) that is not parallel to the vertical direction and a through-slit (Sb) that is not parallel to the horizontal direction (however, the through-slit (Sa) and the through-slit (Sb) may be the same or different). [2] The packaging bag described in [1], A packaging bag in which the maximum length (X) of the through-slit (S) is 100 μm or more and 1000 μm or less. [3] The packaging bag described in [1] or [2], The packaging bag has a through slit (S) which is bent or curved. [4] A packaging bag as described in any one of [1] through [3], A packaging bag in which the maximum length (X) (μm) of the through-slit (S) and the line segment (Y) (μm) connecting one end of the through-slit (S) to the other end at the maximum length (X) satisfy 1.02 ≤ X / Y ≤ 1.70. [5] A packaging bag as described in any one of [1] through [4], A packaging bag in which the line segment (Y) connecting one end to the other end of the through-slit (S) at the maximum length (X) of the through-slit (S) has an angle θ, which is the smaller of the angles it makes with the vertical or horizontal direction, of 2° ≤ θ ≤ 90°. [6] A packaging bag as described in any one of [1] through [5], The aforementioned through slit (S) is A packaging bag having a through slit (Sab) in which through slits (Sa) and through slits (Sb) are identical to each other. [7] [1] to [6] A packaging bag as described in any one of the above, A packaging bag in which the ratio of the through-slit (Sa) and the through-slit (Sb) is 30% or more and 100% or less of the total through-slit (S). [8] [1] to [7] A packaging bag as described in any one of the above, The aforementioned through slit (S) is A packaging bag comprising, separately, a through-slit (Sa) that is not parallel to the longitudinal direction and a through-slit (Sb) that is not parallel to the transverse direction. [9] [1] to [8] A packaging bag described in any one of the above, The packaging bag has a through slit (Sc) comprising a first through slit (S) and a second through slit intersecting the first through slit.

[10] [1] to [9] A packaging bag described in any one of the following: A packaging bag having 1 or more and 500 or fewer through-slits (S).

[11] [1] to

[10] A packaging bag described in any one of the above, A packaging bag in which, at the maximum length (X) of a plurality of through slits (S), the line segments (Y) connecting one end to the other are not parallel to each other.

[12] [1] to

[11] A packaging bag described in any one of the above, The aforementioned synthetic resin film is a packaging bag containing polyolefin.

[13] A packaging bag as described in any one of [1] through

[12] , The packaging bag made of the synthetic resin film has a thickness of 10 μm to 200 μm.

[14] A fresh produce freshness retention bag that uses the packaging bag according to any one of [1] to

[13] for retaining the freshness of fresh produce.

[15] A packaged product containing fresh produce, which is obtained by sealing fresh produce with the fresh produce freshness retention bag according to

[14] .

[16] A method for retaining the freshness of fresh produce, which includes a step of accommodating fresh produce inside the fresh produce freshness retention bag according to

[14] and then sealing the fresh produce freshness retention bag. [Effects of the Invention]

[0008] According to the present invention, a technique related to a packaging bag made of a synthetic resin film capable of suppressing a change in the shape of a through slit is provided. [Brief Description of the Drawings]

[0009] [Figure 1] It is a schematic plan view showing the packaging bag of the first embodiment. [Figure 2] It is a schematic diagram for explaining the maximum length (X) and the line segment (Y) of the through slit (S1). [Figure 3] It is a schematic diagram for explaining the angle θ of the through slit (S1). [Figure 4] It is a schematic plan view showing a modified example of the through slit (S1) of the first embodiment. [Figure 5] It is a schematic plan view showing the packaging bag of the second embodiment. [Figure 6] It is a schematic plan view showing a modified example of the through slit (S2). [Figure 7] It is a schematic diagram showing each through slit (S) of the packaging bag of the example. [Modes for Carrying Out the Invention]

[0010] Hereinafter, an example of an embodiment of the present invention will be described in detail while referring to the drawings. In all drawings, similar components are denoted by the same reference numerals, and explanations are omitted where appropriate. Furthermore, all drawings are for illustrative purposes only. The shapes and dimensional ratios of each component in the drawings do not necessarily correspond to actual items.

[0011] In this specification, the notation "a~b" in descriptions of numerical ranges means a or more and b or less, unless otherwise specified. For example, "1~5 mass%" means "1 mass% or more and 5 mass% or less."

[0012] In this specification, MD direction refers to Machine Direction and is intended to be the flow direction of the resin or sheet, and TD direction refers to Transverse Direction and is intended to be the direction perpendicular to the flow direction.

[0013] In this specification, a through-slit (S) refers to a fine linear gap with a width of less than 25 μm. The shape of the through-slit (S) is not particularly limited and may include, for example, a straight line, a curved line, a straight line with a bend, a straight line with a bend, or a combination thereof.

[0014] Furthermore, if there are multiple through slits (S), their shape, length, size, position, orientation, etc., may be the same, or at least one of them may be different. Specifically, the line segments (Y) connecting one end to the other end of the multiple through slits (S) may not be parallel to each other.

[0015] In the first embodiment described below, the through-slit (S) will be explained using an example in which a through-slit (Sab) is formed by a through-slit (Sa) that is not parallel to the vertical direction and a through-slit (Sb) that is not parallel to the horizontal direction, and these two through-slits (Sab) are identical to each other. In the second embodiment, examples are given in which the through-slit (Sa) that is not parallel to the vertical direction and the through-slit (Sb) that is not parallel to the horizontal direction are different from each other. However, the through slit (S) may have all of the through slits (Sab), through slit (Sa), and through slit (Sb), or it may have the through slit (Sab) and through slit (Sa) but not the through slit (Sb), or it may have the through slit (Sab) and through slit (Sb) but not the through slit (Sa).

[0016] The maximum length (X) of the through-slit (S), the length of the line segment (Y), and the angle θ, which will be described later, are all average values.

[0017] In the diagram, the direction in which the openings 20 of packaging bags 100 and 200 widen is defined as the horizontal direction (W direction), and the direction perpendicular to the horizontal direction is defined as the vertical direction (H direction).

[0018] Furthermore, the position of the through-slit (S) in the main body 10 shown in the figure is an example and is not limited to those shown in the drawing.

[0019] <First Embodiment> Figure 1 is a schematic plan view showing the packaging bag 100 of this embodiment. As shown in Figure 1, the packaging bag 100 has a main body 10 for containing the contents and an opening 20 for inserting and removing the contents. The main body 10 is made of a synthetic resin film and has a plurality of through-slits (S1). In this embodiment, the packaging bag 100 is made of a synthetic resin film.

[0020] In the first embodiment, the through-slit (S1) includes both a through-slit (Sa) that is not parallel to the vertical direction and a through-slit (Sb) that is not parallel to the horizontal direction, and the through-slit (Sa) and the through-slit (Sb) are the same. In the following explanation, a slit where through-slit (Sa) and through-slit (Sb) are the same will be referred to as through-slit (Sab).

[0021] The packaging bag 100 has a through-slit (Sab), which helps to suppress deformation of the through-slit (S1). In other words, even if stress is applied to the bag body 10 due to the weight or movement of the contents, the stress on the through-slit (S1) can be distributed, and expansion, elongation, cracking, etc., of the through-slit (S1) can be suppressed. Furthermore, since synthetic resin films generally have an MD direction and a TD direction, the packaging bag 100 using it tends to deform easily in the transverse or longitudinal direction. Therefore, by having a through-slit (Sab) in this embodiment that is not parallel to either the longitudinal or transverse direction, deformation of the through-slit (S1) can be effectively suppressed.

[0022] Furthermore, when packaging fruits and vegetables, deformation of the through-slit (S) can be suppressed to a high degree during transportation and storage of the fruit and vegetable packaging, thereby reducing even slight fluctuations in the breathability and moisture permeability of the packaging bag 100, and thus improving the freshness preservation effect of the fruits and vegetables.

[0023] Although Figure 1 shows an example in which the main body 10 has nine through-slits (S1), the number of through-slits (S1) may be one or more. Furthermore, the position of the through-slits (S1) in the main body 10 is not limited.

[0024] The details of the through-slit (S1) of the packaging bag 100 are described below.

[0025] [Through-hole slit (S1) / Through-hole slit (Sab)] The through-slit (Sab) in the first embodiment has a curved portion and is substantially arc-shaped, and is not parallel to either the vertical direction (H direction) or the horizontal direction (W direction). In other words, the through-slit (Sab) is not parallel to either the vertical direction or the horizontal direction of the packaging bag 100.

[0026] In the first embodiment, the through-slit (Sab) is described as being approximately arc-shaped, but the through-slit (Sab) is not limited to this, as it is not parallel to either the vertical or horizontal direction of the packaging bag 100. For example, as shown in Figure 4, it may be a diagonal straight line (Figure 4(a)), an X mark (Figure 4(b)), a straight line with a bend (Figure 4(c)), a wavy shape (Figure 4(d)), a combination of a curve and a straight line (Figure 4(e)), etc.

[0027] (Maximum length) The maximum length (X) of the through-slit (S1) is preferably 100 μm or more, more preferably 150 μm or more, and even more preferably 200 μm or more. This allows for improved air permeability while suppressing deformation of the through-slit (S1). On the other hand, the maximum length (X) of the through-slit (S1) is preferably 1000 μm or less, more preferably 800 μm or less, and even more preferably 500 μm or less. This suppresses deformation of the through-slit (S1) while making it easier to suppress drying of the contents and suppress respiration of fruits and vegetables.

[0028] (Quantity) The number of through-slits (S1) in the main body portion 10 is preferably one or more, more preferably two or more, and even more preferably three or more. This allows for improved ventilation while suppressing deformation of the through-slits (S1). On the other hand, the number of through-slits (S1) in the main body 10 is preferably 500 or less, more preferably 300 or less, and even more preferably 200 or less. This suppresses deformation of the through-slits (S1) while making it easier to suppress drying of the contents and suppress respiration of fruits and vegetables.

[0029] (Flexibility / bendability) As shown in Figure 2, the maximum length (X) (μm) of the through slit (S1) and the line segment (Y) (μm) connecting one end to the other end of the through slit (S1) at the maximum length (X) preferably satisfy 1.02 ≤ X / Y ≤ 1.70, and more preferably satisfy 1.02 ≤ X / Y ≤ 1.50. Setting X / Y to be greater than or equal to the lower limit means that X is longer than Y, which implies that the through-slit (S1) is bent or curved. Therefore, setting X / Y to be greater than or equal to the lower limit makes it easier to suppress the deformation of the through-slit (S1). On the other hand, keeping X / Y below the above upper limit means that X is not too long than Y, and the degree of bending and curvature is gentle. Therefore, by keeping X / Y below the above upper limit, it is possible to suppress deformation caused by stress on a part of the through-slit (S1). Specifically, for example, it is possible to suppress the two ends of the through-slit (S1) from connecting due to deformation of the through-slit (S1), or the through-slit (S1) from distorting and widening the opening.

[0030] For example, as shown in Figure 3(a), even if the through-slit (S1) has a slit that intersects the arc-shaped slit, X can be determined by focusing on the maximum length of the through-slit (S1) and setting X, and then defining Y as the line segment connecting one end of the set X to the other end.

[0031] (non-parallelism) Furthermore, as shown in Figure 2, it is preferable that the smaller of the angles θ between the line segment (Y) connecting one end of the through-slit (S1) to the other end at the maximum length (X) of the through-slit (S1) and the vertical direction (H direction) or horizontal direction (W direction) of the packaging bag 100 is 2° ≤ θ ≤ 90°. Setting the angle θ to be greater than or equal to the lower limit means that the line segment (Y) is not parallel to the vertical direction (H direction) and the horizontal direction (W direction), but is inclined. Therefore, by setting the angle θ to be greater than or equal to the lower limit, the line segment is no longer parallel to the vertical direction (H direction) and the horizontal direction (W direction), making it easier to distribute stress and thus easier to suppress the deformation of the through-slit (S1). On the other hand, when the angle θ is the upper limit value (90°), it is intended that the line segment (Y) is parallel to the vertical direction (H direction) or the horizontal direction (W direction). However, in this embodiment, since the through slit (S1) is bent, deformation of the through slit (S1) is also easily suppressed in this case (see Figure 3(c)).

[0032] In Figure 2, the angle θ between the line segment (Y) and the vertical direction (H direction) of the packaging bag 100 was explained. However, if the angle between the line segment (Y) and the horizontal direction (W direction) of the packaging bag 100 is smaller, it is preferable that the angle between the line segment (Y) and the horizontal direction (W direction) of the packaging bag 100 is 2° ≤ θ ≤ 90°. For example, Figure 3(b) shows the case where the angle between the line segment (Y) and the horizontal direction (W direction) of the packaging bag 100 is smaller.

[0033] On the other hand, through slits (S1) with an angle θ greater than 0° and less than 2° are intended to have line segments (Y) parallel to the vertical or horizontal direction.

[0034] (Through hole) The through-slit (S1) may further have a through-hole. The through-hole is integral with the through-slit (S1), is wider than the through-slit (S1), and is a substantially circular opening. The diameter of the through-hole is preferably 25 μm to 50 μm, more preferably 30 μm to 45 μm, and even more preferably 32 μm to 40 μm. For example, Figure 1 shows a through-slit (Sabd) with a through hole.

[0035] Through holes can be formed by known methods such as laser processing and needle processing methods including hot needles.

[0036] (interval) When there are multiple through-slits (Sab), the spacing between adjacent through-slits (Sab) is preferably 3 mm or more, more preferably 5 mm or more, and even more preferably 8 mm or more, in order to more effectively suppress the deformation of the through-slits (Sab).

[0037] (ratio) In the first embodiment, 100% of the through-slits (S1) are through-slits (Sab). That is, out of 9 through-slits (S1), 9 are through-slits (Sab). However, the proportion of through-slits (Sab) is not limited to this. For example, the proportion of through slits (Sab) may be 30% or more, 50% or more, or 70% or more of the total number of through slits (S1). Specifically, for example, if there are 4 through slits (S1), and 1 of the 4 is a through slit (Sab), then the proportion of through slits (Sab) is 25%. In particular, from the standpoint of suppressing deformation and enhancing the freshness preservation effect, it is preferable that the proportion of through-slits (Sab) be 30% or more of the total through-slits (S1).

[0038] (Formation means / method) The above-mentioned through-slit (S1) may be provided in the synthetic resin film in advance when manufacturing the packaging bag 100, may be provided after the synthetic resin film has been formed into a bag shape, or may be provided before or after the synthetic resin film has been formed into a bag shape.

[0039] The method for forming the through-slit (S1) described above is not particularly limited, and known methods can be employed. Examples of such known methods include needle processing methods including a hot needle, methods using molds such as a roll cutter, and laser processing methods. Details will be explained below.

[0040] Needles include sewing needles, hypodermic needles, and acupuncture needles, and come in various thicknesses and tip shapes to suit their respective uses, but there is no limit to the type of needle that can be used. When using a needle, the angle and degree of curvature of the slit can be changed by the type of needle, tip shape, angle, thickness, the angle at which the needle itself is placed, the depth of insertion, the direction and speed of movement of the needle and film, and the tension of the film. Needle shapes can be broadly classified into those that taper uniformly towards the tip, like sewing needles, and those that have a tip that resembles a rod cut at an angle, like hypodermic needles. Using the latter type of needle, which has anisotropy, makes it easier to create curved slits.

[0041] Blades include spring blades, engraving blades, and etching blades, each differing in thickness, shape, and durability, but there are no restrictions on which type of blade to use. When using a blade, the shape and direction of the slit can be controlled by the shape and direction of the blade. The tip of the blade can be a miniature version of a carving knife, such as a flat blade, a cutting blade, a round blade, or a triangular blade. By using a tiny round or triangular blade, it is possible to create a slit with a controlled shape and high degree of curvature.

[0042] While the type of laser is not particularly limited, a high-power carbon dioxide laser can be suitably used. By moving the laser head or film during laser irradiation, slits with controlled angles and shapes can be continuously created. The method for creating multiple slits simultaneously or sequentially is not limited, but one example is pressing a roll or board equipped with multiple needles or blades against the film. Methods for creating such a roll or board include individually installing and fixing numerous needles or blades to the roll or board, or using photolithography techniques to create a flexible die with multiple etching needles or blades simultaneously, and then fixing this die to the roll or board. Using a flexible die makes it easy to arrange blades of various shapes in random positions and directions.

[0043] Another method that can be used is the use of a perforating blade. A perforating blade is a blade with a structure in which many tiny blades are arranged continuously in the width direction of the blade. Generally, it is used for the purpose of separating processed paper or film along perforations, so a general perforating blade is not effective for this invention. This is because the distance between the blades is too close. In this embodiment, when using a perforating blade, it is preferable to use a perforating blade in which the distance between the blades is about a few millimeters, preferably 5 mm or more.

[0044] While there are no restrictions on the material of the needles and blades, their durability can be improved by treating the surface with DLC coating or similar methods.

[0045] (Verification / Measurement Method) The method for measuring the dimensions of the through-slit (S1) is not particularly limited, but examples include taking an enlarged image of the through-slit (S1), printing the image, actually measuring the photograph, and calculating the dimensions from the magnification of the photograph, or using a digital microscope for measurement. Examples of digital microscopes include the HRX-01 and RX-100 from Hirox Corporation, the VHX series from Keyence Corporation, and the DSX1000 from Olympus Corporation.

[0046] <Second Embodiment> Next, the packaging bag 200 of the second embodiment will be described in terms of its different configuration and operation compared to the packaging bag 100 of the first embodiment.

[0047] Figure 5 is a schematic plan view showing the packaging bag 200 of the second embodiment. As shown in Figure 5, the packaging bag 200 has a main body 10 for containing the contents and an opening 20 for putting in and taking out the contents. The main body 10 is made of a synthetic resin film and has a plurality of through slits (S2).

[0048] In the second embodiment, the through-slit (S2) includes both a through-slit (Sa) that is not parallel to the longitudinal direction and a through-slit (Sb) that is not parallel to the transverse direction, and the through-slit (Sa) and the through-slit (Sb) are different.

[0049] The packaging bag 200 has through-slits (Sa) and (Sb), which suppresses deformation of the through-slit (S2). In other words, even if stress is applied to the bag body 10 due to the weight or movement of the contents, the stress on the through-slit (S2) can be distributed, and expansion, elongation, cracking, etc., of the through-slit (S2) can be suppressed. Furthermore, since synthetic resin films generally have an MD direction and a TD direction, packaging bags 200 made using them tend to deform easily in the lateral or longitudinal direction. Therefore, by having both a through-slit (Sa) that is not parallel to the longitudinal direction and a through-slit (Sb) that is not parallel to the lateral direction in this embodiment, even if one is easily deformed, the other will not deform easily, thus suppressing deformation of the through-slit (S2) as a whole in the packaging bag 200.

[0050] In addition, when packaging fruits and vegetables, it is possible to reduce fluctuations in the breathability and moisture permeability of the packaging bag 200, thereby improving the freshness preservation effect of the fruits and vegetables.

[0051] In Figure 5, an example is shown in which the main body 10 has nine through-slits (S2), four through-slits (Sa), and five through-slits (Sb). However, the number of through-slits (S2), (Sa), and (Sb) is not limited to this. Furthermore, the position of the through-slits (S2) in the main body 10 is not limited.

[0052] The details of the through-slit (S2) of the packaging bag 200 are described below.

[0053] [Through-hole slit (S2) / Through-hole slit (Sa) / Through-hole slit (Sb)] The through-slit (Sa) in the second embodiment is not parallel to the vertical direction, but is a straight line parallel to the horizontal direction. The through-slit (Sb) is a straight line parallel to the vertical direction, but not parallel to the horizontal direction.

[0054] In the second embodiment, examples are given where both the through-slit (Sa) and the through-slit (Sb) are straight lines. However, the through-slits (Sa) and (Sb) are not limited to this, and may be T-shaped (Figure 6(a)), L-shaped (Figure 4(b)), cross-shaped (Figure 6(c)), U-shaped (Figure 6(d)), S-shaped (Figure 6(e)), etc., as shown in Figure 6. Furthermore, the through-slit (S1) may have a through-slit (Sc) consisting of a first through-slit and a second through-slit intersecting the first through-slit. In this case, the length and shape of the first and second through-slits are not particularly limited, nor is the position of their intersection particularly limited.

[0055] (ratio) In the second embodiment, the proportion of through slits (Sa) is 0% or more of the total through slits (S2), and from the viewpoint of suppressing deformation and enhancing the freshness preservation effect, it is preferably 30% or more, more preferably 50% or more, even more preferably 70% or more, and even more preferably 100%. The proportion of through-slits (Sb) is 0% or more of the total through-slits (S2), and from the viewpoint of suppressing deformation and enhancing the freshness preservation effect, it is preferably 30% or more, more preferably 50% or more, even more preferably 70% or more, and even more preferably 100%.

[0056] The other configurations and functions of the through-slit (S2) are the same as those of the through-slit (S1) described in the first embodiment.

[0057] The following describes the common features and functions of packaging bag 100 and packaging bag 200.

[0058] [Main body] The main body 10 is for containing the contents and is in the shape of a bag. The main body 10 is formed from synthetic resin.

[0059] (Synthetic resin) The synthetic resin can be appropriately selected depending on the application, considering factors such as mechanical strength, handling, and processability. However, it is preferable to use one or more types selected from the group consisting of polyethylene, polypropylene, polyester, polystyrene, polyvinyl chloride, (meth)acrylic resin; polyester resins such as polyethylene terephthalate and polylactic acid; and polyamide resins such as nylon.

[0060] The polyethylenes mentioned above include various types of polyethylene and ethylene copolymers. Specific examples include high-density polyethylene (HDPE), medium-density polyethylene, low-density polyethylene, linear low-density polyethylene (LLDPE), metallocene-linear low-density polyethylene, ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-α-olefin copolymer, and other copolymers or ionomers. The linear low-density polyethylene described above is typically a copolymer of ethylene and a small amount of α-olefin. The type of α-olefin is not particularly limited. Typical α-olefins include α-olefins with 3 to 10 carbon atoms, such as 1-propylene, 1-butene, 1-hexene, 4-methylpentene-1, and 1-octene. Among these, 1-propylene is preferred. The ethylene content of the ethylene-propylene copolymer is typically 4.5% or less.

[0061] Examples of polypropylenes mentioned above include homopolymers, random copolymers, and block copolymers. More specifically, examples of homopolymers include isotactic polypropylene, syndiotactic polypropylene, and atactic polypropylene, while examples of random copolymers include ethylene-propylene copolymers, propylene-1-butene copolymers, and propylene-octene copolymers. Among these, random copolymers are preferred.

[0062] Examples of the polyamide resins mentioned above include nylon. Nylon can be nylon 6, nylon 11, nylon 12, nylon 66, nylon 6-10, nylon 6-12, nylon 6-T, nylon 6-I, nylon 9T, nylon M5T, polymetaxylylene adipamide (MXD nylon), etc., and can be used individually or in combination of two or more. Among these, nylon 6, nylon 11, nylon 12, and nylon 66 individually or in combination of two or more are preferred, and nylon 6 and nylon 66 individually or in combination of two are even more preferred.

[0063] The synthetic resin film may contain additives such as antifogging agents, antiblocking agents, heat stabilizers, lubricants, impact modifiers, processing aids, antistatic agents, ultraviolet absorbers, antioxidants, weather degradation inhibitors, fillers, and pigments, as needed, to the extent that they do not impair the performance of the synthetic resin film.

[0064] (Film manufacturing method) The method for obtaining the synthetic resin film is not particularly limited. Examples of known methods for obtaining a synthetic resin film include extrusion, inflation, and calendering. Furthermore, the synthetic resin film may be subjected to stretching or annealing, but it may also be left unstretched. If stretching is performed, the stretching ratio is not particularly limited, but for example, it can be about 2 to 5 times in both the MD direction and the TD direction. Furthermore, the synthetic resin film may be subjected to stretching, annealing, or other treatments.

[0065] (Thickness) The thickness of the synthetic resin film is preferably 10 to 200 μm, more preferably 15 to 100 μm, and even more preferably 20 to 50 μm.

[0066] (Layer composition) The synthetic resin film may be a single layer or a multilayer film of two or more layers.

[0067] By using a multilayer structure for the synthetic resin film, desired functionality can be enhanced. For example, by adding functions such as slipperiness to the surface layer of the synthetic resin film, the handling and heat-sealing properties of the synthetic resin film can be improved, and packaging bags with an excellent balance of stretchability and rigidity can be reliably obtained. Alternatively, for example, by using a two- or three-layer structure for the synthetic resin film and making at least one of the surface layers a layer containing an anti-blocking agent, slipperiness can be obtained. Furthermore, for example, a sealant layer may be added to provide heat-sealability.

[0068] In the case of a multilayered synthetic resin film, the base resins of each layer may be the same or different. From the viewpoint of obtaining good adhesion between layers, it is preferable that each layer uses the same resin.

[0069] Known methods such as dry lamination, extrusion lamination, co-extrusion, and coating can be used as appropriate to obtain multilayer films. From the viewpoint of improving interlayer adhesion and controlling layer thickness, co-extrusion is preferred.

[0070] (Oxygen permeability) The oxygen permeability of the synthetic resin film at 23°C and 60% RH is preferably 200 cc / (m²), particularly when packaging fresh produce, from the viewpoint of maintaining the respiration of the produce and preserving its freshness. 2 (day·atm) or more, more preferably 500cc / (m 2 (day·atm) or more, and even better is 800cc / (m 2·day·atm) or more, more preferably 1000 cc / (m 2 ·day·atm) or more. On the other hand, the oxygen permeability of the synthetic resin film at 23°C and 60% RH is preferably 1,000,000 cc / (m 2 ·day·atm) or less, more preferably 300,000 cc / (m 2 ·day·atm) or less, still more preferably 100,000 cc / (m 2 ·day·atm) or less, even more preferably 50,000 cc / (m 2 ·day·atm) or less, from the viewpoint of maintaining the quality and freshness of fruits and vegetables especially when packaging them.

[0071] (Water vapor permeability) The water vapor permeability of the synthetic resin film at 40°C is preferably 1 g / (m 2 ·day) or more, more preferably 3 g / (m 2 ·day) or more, from the viewpoint of releasing the water vapor due to the respiration of fruits and vegetables especially when packaging them. On the other hand, the water vapor permeability of the synthetic resin film at 40°C is preferably 300 g / (m 2 ·day) or less, more preferably 100 g / (m 2 ·day) or less, still more preferably 50 g / (m 2 ·day) or less, even more preferably 10 g / (m 2 ·day) or less, from the viewpoint of suppressing the respiration of fruits and vegetables especially when packaging them.

[0072] The water vapor permeability can be measured by a method conforming to JIS Z 0208 (cup method).

[0073] [Opening] The opening 20 is located on the upper side of the packaging bag 100 and the packaging bag 200, and is an opening for taking in and out the contents. The opening 20 is sealed using heat sealing, back sealing tape, cable ties, rubber bands, or other materials such as rivets. Alternatively, a zipper or the like may be provided on the main body 10 to allow the opening 20 to be easily opened and closed.

[0074] [Bag shape] The shapes of the packaging bags 100 and 200 in this embodiment are not particularly limited and can be known bag shapes such as two-sided bags, three-sided bags, U-shaped bags, back-sealed bags (gusseted bags), pouches, and gusseted bags. For example, the two-sided bag described above is a bag made by folding a synthetic resin film in half, using the folded part as the bottom, and sealing both sides. A three-sided bag is a bag made by overlapping two sheets of synthetic resin film and sealing the bottom and both sides. A U-shaped bag is a bag in which the bottom part is heat-sealed in a U shape. The seal in question can be a heat-cut seal obtained by heat-cutting a synthetic resin film. Heat cutting is a method of cutting a synthetic resin film with heat using a hot wire while melting and bonding the cut portion of the synthetic resin film.

[0075] The dimensions (length and width) of the packaging bags 100 and 200 in this embodiment can be appropriately designed depending on the application and contents. For example, for packaging fresh produce intended for general consumers, the dimensions can be approximately 40mm x 40mm to 350mm x 400mm.

[0076] [Applications, packaged items] The contents are not particularly limited as long as they are suitable for moderate ventilation, but examples include one or more items selected from fruits and vegetables, processed foods (fermented foods), medical supplies, and fragrances. Specifically, for example, when packaging fermented foods such as kimchi, the generated gas can be released to the outside through the through-slit (S), preventing the packaging bags 100 and 200 from bursting or breaking. Also, for example, when packaging fragrances, a constant amount of fragrance can be stably released through the through-slit (S), making it suitable for use as an air freshener. Furthermore, for example, after packaging medical supplies, sterilization gas can be sealed inside through the through-slit (S), improving the hygiene and safety of the medical supplies. In particular, it is more effective for packaging fruits and vegetables because it can suppress fluctuations in air permeability and moisture permeability due to slight deformation of the through-slit (S). The following explains the case where fruits and vegetables are stored.

[0077] (Fruits and vegetables) Fresh produce refers to vegetables grown in soil or hydroponically, from which non-edible parts such as roots, peels, cores, stems, seeds, and flowers have been removed. The edible portion of the vegetable is then prepared in a way that is easy to eat and prepare, without heating.

[0078] As for fruits and vegetables, there are no particular limitations, but for example, semi-heading and heading vegetables such as cabbage, Chinese cabbage, lettuce (lettuce, leaf lettuce, romaine lettuce, sunny lettuce, salad lettuce, ssamjang, etc.), and Brussels sprouts; spinach, komatsuna, mizuna, bok choy, rapeseed (kakina), non-heading lettuce (romaine lettuce, sunny lettuce, etc.), garland chrysanthemum, stem vine, santouna, rapeseed, curly lettuce, kousaitai, urui, field wasabi, flower wasabi, watercress, arugula, shepherd's purse, petit vert, ice plant, leaf radish, etc.; root vegetables such as sweet potato, potato, nagaimo, yamaimo, taro, jinenjo, and yamatoimo, radish, carrot, burdock, turnip, ginger; leeks, ta Examples include: onions, chives and other Allium vegetables; broccoli and cauliflower; cucurbitaceous fruits and vegetables such as cucumbers and pumpkins; nightshade fruits and vegetables such as eggplants, tomatoes, cherry tomatoes, bell peppers, and paprikas; and fruits and vegetables such as okra, bitter melon, zucchini, and sweet corn; immature beans such as edamame, snow peas, green beans, and broad beans; stem vegetables such as celery, asparagus, and wasabi; herbs such as myoga ginger, perilla, water dropwort, mitsuba, and herbs (thyme, sage, parsley, Italian parsley, rosemary, oregano, lemon balm, chives, lavender, salad burnet, lamb's ear, arugula, dandelion, and nasturtium); and mushrooms. These may be packaged individually or in combination of two or more types.

[0079] Fresh produce may be cut as appropriate, taking into consideration purchasing and consumption, and may be roughly divided into 1 / 8 to 1 / 2 portions, for example, in terms of purchasing appeal, such as cabbage, Chinese cabbage, and pumpkin. Furthermore, it may be cut into bite-sized pieces or julienned for raw consumption in salads, or for cooking in stir-fries.

[0080] <Packaged fruit and vegetable product> The fruit and vegetable packaging of this embodiment (hereinafter also referred to as "packaging") contains fruit and vegetable in the packaging bags 100 and 200 described above. This improves the freshness preservation effect of the fruit and vegetable.

[0081] The packaging is preferably sealed at the opening 20. For sealing, known methods can be used, such as heat sealing the opening 20 of the bag, or using back sealing tape (back seal), cable ties, rubber bands, or crimping materials. In the case of a bag with a zipper, the opening 20 can be closed with the zipper.

[0082] The amount of fresh produce contained in packaging bags 100 and 200 may vary depending on the size of the container, the type of fresh produce, and the intended use of the packaging. For fresh produce intended for general consumers, for example, from the viewpoint of being easy to consume immediately after opening and being easy to carry and handle, the amount is preferably 50 to 1000 g, more preferably 100 to 800 g.

[0083] <Methods for maintaining freshness> The freshness preservation method of this embodiment includes the step of storing the produce using the above-described package containing the produce. Storage can be carried out by known methods, but it is preferable to store the packaged product at an ambient temperature of 2 to 20°C. Ambient temperature refers to, for example, the temperature setting of the refrigerator or refrigerator where the packaged product is stored, or the temperature control setting of the display case where the packaged product is displayed in a store. It does not refer to a precisely measured temperature around the packaged product. Furthermore, it is sufficient for the average ambient temperature to be between 2 and 20°C, and it may temporarily drop to around 10°C due to unavoidable circumstances such as opening and closing doors during transport of the packaged product.

[0084] Although embodiments of the present invention have been described above, these are merely examples, and various other configurations can be adopted. Furthermore, the present invention is not limited to the embodiments described above, and modifications, improvements, etc., within the scope that can achieve the objectives of the present invention are included in the present invention. [Examples]

[0085] The present invention will be described in detail below based on examples and comparative examples. It should be noted that the present invention is not limited to the examples provided.

[0086] (1) Preparation of packaging bags The following synthetic resin films were prepared and used for each packaging bag. Tables 1-4 show the material and thickness of each synthetic resin film. (material) • OPP: Biaxially oriented polypropylene • LLDPE: Linear low-density polyethylene • HDPE: High-density polyethylene Next, using synthetic resin film, heat-sealed bags, heat-sealed bags with zippers, U-shaped bags (bags with the bottom sealed in a U-shape), and back-sealed bags were fabricated using known methods to achieve the bag sizes (length x width) shown in Tables 1 to 4. For heat-sealed bags, heat-sealed bags with zippers, and U-shaped bags, the vertical direction of the bag was aligned with the TD direction of the synthetic resin film, while for back-sealed bags, the vertical direction of the bag was aligned with the MD direction of the synthetic resin film. Furthermore, each packaging bag was provided with a through-slit (S) as shown in Tables 1-4 and Figure 7, using known methods.

[0087] (2) Observation of through slit (S) The through-slit (S) was observed using a digital microscope (RX-100, manufactured by Hirox Co., Ltd.). The results are shown in Tables 1-4.

[0088] (3) Evaluation method Each of the obtained packaging bags was filled with the fruits and vegetables (type, quantity) shown in Table 1, and sealed using the sealing method shown in Table 1 to obtain a package containing fruits and vegetables. Next, the produce was stored in packages according to the following conditions 1 and 2, and then the produce was removed and evaluated according to the following evaluation criteria. The evaluation was performed by a technician familiar with produce freshness preservation bags. In addition, the maximum length (X) of the through-slit (S) of the packaging bag was measured and the average value was calculated. At this time, the maximum length of the through-slit (S) after storage under condition 1 was defined as X1, and the maximum length of the through-slit (S) after storage under condition 2 was defined as X2. These results are shown in Tables 1 to 4.

[0089] (Condition 1) After obtaining the packages containing fresh produce, they were stored at the temperatures and for the durations shown in Tables 1-4. (Condition 2) After obtaining the packages containing fresh produce, they were subjected to a 30-minute vibration test under the conditions described in JIS Z0232, and then stored at the temperatures and for the durations shown in Tables 1-4. The vibration test was conducted using a transport packaging vibration testing device (FT-02K / 100) manufactured by EMIC Co., Ltd. (Evaluation Criteria) ◎5: No visible signs of deterioration in freshness. 〇4: Slight deterioration in appearance due to lack of freshness. △3: Appearance shows moderate deterioration in freshness. ×2: Clearly shows signs of reduced freshness in appearance. ××1: Noticeable deterioration in appearance.

[0090] Furthermore, even if the freshness of the produce deteriorated due to the vibration test under Condition 2, the evaluation focused solely on the relative change in appearance (decreased freshness) before and after storage, based on the condition after the vibration test.

[0091] [Table 1]

[0092] [Table 2]

[0093] [Table 3]

[0094] [Table 4]

[0095] Each packaging bag in the examples had through-slits that were not parallel to the vertical or horizontal directions of the bag, whereas Comparative Examples 1-4 had a single through-slit parallel to the vertical direction, and Comparative Examples 5-6 had a single through-slit parallel to the horizontal direction. As a result, the percentage change in the length of the through-slits (X2 / X) before and after the test under condition 2 was lower for the examples than for the comparative examples, indicating that the through-slits were not torn and extended by stress, nor were they deformed and widened. Furthermore, when packaging fruits and vegetables, the packaging bags of the examples showed better freshness preservation than the comparative examples.

Claims

1. The main body contains the contents, An opening for inserting and removing the contents, A packaging bag having the main body made of synthetic resin film, The main body portion has a through slit (S), When the direction in which the opening widens is defined as the horizontal direction, and the direction perpendicular to the horizontal direction is defined as the vertical direction, The through-slit (S) includes both a through-slit (Sa) that is not parallel to the vertical direction and a through-slit (Sb) that is not parallel to the horizontal direction (however, the through-slit (Sa) and the through-slit (Sb) may be the same or different).

2. A packaging bag according to claim 1, A packaging bag in which the maximum length (X) of the through-slit (S) is 100 μm or more and 1000 μm or less.

3. A packaging bag according to claim 1 or 2, The packaging bag has a through slit (S) which is bent or curved.

4. A packaging bag according to claim 1 or 2, A packaging bag in which the maximum length (X) (μm) of the through-slit (S) and the line segment (Y) (μm) connecting one end of the through-slit (S) to the other end at the maximum length (X) satisfy 1.02 ≤ X / Y ≤ 1.

70.

5. A packaging bag according to claim 1 or 2, A packaging bag in which the line segment (Y) connecting one end to the other end of the through-slit (S) at the maximum length (X) of the through-slit (S) has an angle θ, which is the smaller of the angles it makes with the vertical or horizontal direction, of 2° ≤ θ ≤ 90°.

6. A packaging bag according to claim 1 or 2, The aforementioned through slit (S) is A packaging bag having a through slit (Sab) which is the same as the through slit (Sa) and the through slit (Sb).

7. A packaging bag according to claim 1 or 2, A packaging bag in which the ratio of the through-slits (Sa) and (Sb) is 30% or more and 100% or less of the total through-slit (S).

8. A packaging bag according to claim 1 or 2, The aforementioned through slit (S) is A packaging bag comprising, separately, a through-slit (Sa) that is not parallel to the vertical direction and a through-slit (Sb) that is not parallel to the horizontal direction.

9. A packaging bag according to claim 1 or 2, The packaging bag has a through slit (Sc) comprising a first through slit (S) and a second through slit intersecting the first through slit.

10. A packaging bag according to claim 1 or 2, A packaging bag having one or more through-slits (S) and not exceeding 500.

11. A packaging bag according to claim 1 or 2, A packaging bag in which, at the maximum length (X) of a plurality of through slits (S), the line segments (Y) connecting one end to the other are not parallel to each other.

12. A packaging bag according to claim 1 or 2, The aforementioned synthetic resin film is a packaging bag containing polyolefin.

13. A packaging bag according to claim 1 or 2, The aforementioned synthetic resin film is a packaging bag having a thickness of 10 μm to 200 μm.

14. A fresh produce freshness preservation bag, wherein the packaging bag according to claim 1 or 2 is used for preserving the freshness of fresh produce.

15. A package containing fresh produce, wherein the fresh produce is sealed using the fresh produce preservation bag described in claim 14.

16. A method for preserving the freshness of fruits and vegetables, comprising the step of placing fruits and vegetables inside the freshness preservation bag for fruits and vegetables described in claim 14, and then sealing the freshness preservation bag for fruits and vegetables.

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