Packaging bag

Abstract

To provide a packaging bag whose opening direction and opening port size are easy to be controlled, when the packaging bag is torn and opened by user's hand.SOLUTION: According to a packaging bag, the packaging bag comprises: a storage part for storing an article, that is constituted from a stretch film containing a polymer; a sealing part for sealing the storage part, that is provided at an end of the storage part; and a cut area part provided at the sealing part. The storage part comprises a first film as the stretch film. An orientation direction of molecules of the polymer contained in the first film is an oblique direction with respect to a height direction to a bottom part as well as a top part of the storage part.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] 2. Description of the Related Art There is a demand for packaging bags for packaging foods, precision parts, medical instruments, and the like that can be easily opened with finger strength, and various studies have been conducted to address this demand (Patent Documents 1 to 5). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-78673 A [Patent Document 2] JP 2013-233934 A [Patent Document 3] JP 2015-150842 A [Patent Document 4] JP 2015-58953 A [Patent Document 5] JP 2000-7016 A Summary of the Invention [Problem to be solved by the invention]

[0004] Packaging bags available on the market are designed to be opened, for example, by tearing the packaging bag vertically or horizontally. For example, when such packaging bags are used to package liquid seasonings, the opening may be too large, causing the seasoning to overflow from the bag or to easily adhere to the film surface that constitutes the bag. Also, when packaging powdered medicine for children, if the opening of the packaging bag is too large, the powder may spill out of the child's mouth, causing the child to drink it. On the other hand, since it is necessary for users to be able to pick up medical equipment or precision parts reliably, it is desirable for the opening of the packaging bag to be wide. As another example, there are cases where the packaging of stick-shaped foods cannot be easily opened.

[0005] As described above, there is a demand for packaging bags available on the market to be opened using an opening method more suited to the intended use.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a packaging bag in which the opening direction and the size of the opening are easily controlled. [Means for solving the problem]

[0007] The inventors conducted intensive research to solve the above-mentioned problems and discovered that by orienting the polymer molecules contained in the stretched film that constitutes the packaging bag in a direction that is oblique to the height direction of the packaging bag, it is possible to effectively control the opening direction and the size of the opening opening, thereby completing the present invention. That is, the present invention provides the following.

[0008] [1] A storage section configured by a stretched film containing a polymer and storing an item; a sealing portion provided at an end of the storage portion and sealing the storage portion; A packaging bag having a cut portion provided in the sealing portion, The storage section has a first film as the stretched film, A packaging bag in which the orientation direction of the polymer molecules contained in the first film is oblique to the height direction from the bottom to the top of the storage section. [2] The packaging bag according to [1], wherein the cut portion is provided in the sealing portion located at the top end or side end of the storage section. [3] The packaging bag according to [1] or [2], wherein the storage section has a second film which is a stretched film facing the first film, and the first film and the second film are laminated at the sealing section. [4] The packaging bag according to [3], wherein the packaging bag is a flat bag. [5] The packaging bag according to any one of [3] to [4], wherein the shape of the storage section when viewed from a direction perpendicular to the main surface of the first film is rectangular. [6] The packaging bag according to any one of [3] to [5], wherein the angle θ1 formed by the orientation direction of the polymer molecules contained in the first film with respect to the height direction of the storage section is greater than 0° and less than 75°, or greater than 115° and less than 180°. [7] The packaging bag according to any one of [3] to [6], wherein the orientation direction of the molecules of the polymer contained in the first film is different from the orientation direction of the molecules of the polymer contained in the second film. [8] The packaging bag according to [1], wherein the storage section has a structure in which the first film is folded. [9] The packaging bag according to [1], wherein the packaging bag has a structure in which the first film is arranged in a cylindrical shape in the storage section.

[10] The packaging bag according to [9], wherein the sealing portion located at the side end of the storage portion has a plurality of cut portions.

[11] The packaging bag according to any one of [1] to

[10] , wherein the packaging bag is made of a multilayer film including the stretched film. Effect of the Invention

[0009] According to the present invention, a packaging bag can be provided in which the opening direction and the size of the opening opening can be easily controlled. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1(a) is a plan view that illustrates an example of a packaging bag according to a first embodiment of the present invention, and FIG. 1(b) is a cross-sectional view of the packaging bag shown in FIG. 1(a) taken along line AA. [Diagram 2] FIG. 2 is a diagram for explaining the orientation direction of the stretched film that constitutes the packaging bag shown in FIG. [Diagram 3] FIG. 3 is a plan view that typically shows the state of the packaging bag shown in FIG. 1 after it has been opened. [Figure 4]FIG. 4 is a plan view that illustrates a schematic view of another example of the packaging bag according to the first embodiment of the present invention. [Diagram 5] FIG. 5 is a diagram for explaining the orientation direction of the stretched film that constitutes the packaging bag shown in FIG. [Figure 6] FIG. 6 is a plan view that illustrates a schematic configuration of the packaging bag illustrated in FIG. 4 after it has been opened. [Figure 7] FIG. 7 is a plan view and a cross-sectional view taken along line AA, which are schematic views of another example of a packaging bag according to the second embodiment of the present invention. [Figure 8] FIG. 8 is a development view of the stretched film that constitutes the packaging bag shown in FIG. [Figure 9] FIG. 9 is a plan view that illustrates a schematic configuration of the packaging bag illustrated in FIG. 7 after it has been opened. [Figure 10] FIG. 10 is a plan view that illustrates a schematic view of another example of the packaging bag according to the second embodiment of the present invention. [Figure 11] FIG. 11 is a development view of the stretched film that constitutes the packaging bag shown in FIG. [Figure 12] FIG. 12 is a diagram for explaining the opening direction of the packaging bag shown in FIG. [Figure 13] FIG. 13 is a perspective view that illustrates an example of a packaging bag according to a third embodiment of the present invention. [Figure 14] FIG. 14 is a diagram for explaining the opening direction of the packaging bag shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in detail below with reference to the embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be modified and implemented as desired without departing from the scope of the claims of the present invention and the scope of equivalents thereto. Also, previously mentioned reference numerals in the drawings may be omitted.

[0012] In the following description, unless otherwise specified, the directions of elements as "parallel," "vertical," and "orthogonal" may include an error within a range that does not impair the effect of the present invention, for example, within a range of ±3°, ±2°, or ±1°.

[0013] In the following description, the orientation direction of the polymer molecules contained in the film refers to the orientation direction of the polymer molecules contained in the resin constituting the stretched film. When the resin constituting the stretched film is a resin with positive intrinsic birefringence, the orientation direction of the molecules is the slow axis direction (stretching direction). When the resin constituting the stretched film is a resin with negative intrinsic birefringence, the orientation direction of the molecules is the fast axis direction. The value of intrinsic birefringence can be calculated from the dielectric constant distribution.

[0014] <1. Overview of packaging bags> A packaging bag according to one embodiment of the present invention includes a storage section made of a stretched film containing a polymer and configured to store an item, a sealing section provided at an end of the storage section to seal the storage section, and a cut section provided in the sealing section. In this packaging bag, the storage section has a first film as a stretched film, and the orientation direction of the polymer molecules contained in the first film is oblique to the height direction from the bottom to the top of the storage section. In this packaging bag, it is preferable that the cut section is provided in the sealing section located at the top side end or side end of the storage section.

[0015] In the present invention, the "bottom" and "top" of the storage section of the packaging bag typically refer to the part located at the bottom of the packaging bag when the surface direction of the first film of the storage section is oriented vertically to the ground when the packaging bag is opened, and the part above the bottom and facing the bottom corresponds to the "top". The "bottom" and "top" of such a packaging bag can be determined based on information that can identify the "bottom" and "top" of the packaging bag, for example, when the information is printed, labeled, or otherwise indicated on the outer surface of the packaging bag. In addition, when the packaging bag is transparent and the item stored in the storage section can be observed from the outside of the packaging bag, the "bottom" and "top" can be determined based on the up-down orientation of the item. Furthermore, when opening the packaging bag, if the main surface of the first film of the packaging bag is positioned vertically to the ground, the cut portion is usually provided in the sealing portion located at the top end or side end of the storage section, so the "bottom" and "top" can be determined based on the position of the cut portion.

[0016] Depending on the use of the packaging bag, for example, when the packaging bag is placed on a table so that the surface direction of the first film of the packaging bag is parallel to the ground and opened, the "bottom" and "top" of the storage section of the packaging bag can be determined, for example, from the above-mentioned information and the orientation of the stored item. However, when such information is not available or when it is difficult to determine the up-down orientation of the stored item from its shape, the "bottom" and "top" of the storage section of the packaging bag are defined as follows. When the storage section of the packaging bag has a longitudinal direction and a lateral direction, one end in the longitudinal direction is defined as the "bottom" and the other end as the "top". In this case, when a cut is provided on the side of one end in the longitudinal direction, the end on the side where the cut is provided is defined as the "top" and the opposite end as the "bottom". Also, when the cut is provided on a side end of the storage section, the end closest to the cut in the longitudinal direction is defined as the "top" and the opposite end as the "bottom".

[0017] The oblique direction with respect to the height direction of the storage section refers to an in-plane direction of the stretched film that constitutes the surface of the storage section, which is neither parallel nor perpendicular to the height direction of the storage section.

[0018] In the following description, the orientation direction of the polymer molecules contained in the first film may be referred to as the orientation direction of the first film.

[0019] According to the present invention, since the orientation direction of the first film is oblique to the height direction of the storage section in the packaging bag, when the packaging bag is torn by hand from the cut opening, the first film in the storage section can be opened along the orientation direction of its molecules. Therefore, by adjusting the orientation direction of the first film and the position of the cut opening in the packaging bag, it is possible to obtain a packaging bag in which the opening direction and the size of the opening can be controlled.

[0020] <2. Stretched film> In the packaging bag according to one embodiment of the present invention, the storage section is made of a stretched film containing a polymer. The stretched film is usually made of a resin containing a polymer, and may contain any component as necessary. The resin constituting the stretched film may be a resin having a positive intrinsic birefringence value, or may be a resin having a negative intrinsic birefringence value.

[0021] As the polymer that can be contained in the stretched film, a polymer having thermoplasticity can usually be used. Examples of such polymers include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyarylene sulfides such as polyphenylene sulfide; polyvinyl alcohol; polycarbonate; polyarylate; cellulose ester polymers, polyethersulfone; polysulfone; polyarylsulfone; polyvinyl chloride; polymers containing an alicyclic structure such as norbornene-based polymers; rod-shaped liquid crystal polymers, and the like. The polymer may be used alone or in combination of two or more types in any ratio. The polymer may be a homopolymer or a copolymer. Among these, a polymer containing an alicyclic structure is preferred because it has excellent mechanical properties, heat resistance, transparency, low moisture absorption, dimensional stability, and light weight. Hereinafter, a polymer containing an alicyclic structure may be appropriately referred to as an "alicyclic structure-containing polymer".

[0022] The alicyclic structure-containing polymer is a polymer whose structural unit contains an alicyclic structure. The alicyclic structure-containing polymer may have an alicyclic structure in the main chain or may have an alicyclic structure in the side chain. Among them, from the viewpoint of mechanical strength and heat resistance, the polymer containing an alicyclic structure in the main chain is preferred.

[0023] Examples of the alicyclic structure include saturated alicyclic hydrocarbon (cycloalkane) structures, unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structures, etc. Among these, from the viewpoint of mechanical strength and heat resistance, cycloalkane structures and cycloalkene structures are preferred, and cycloalkane structures are particularly preferred.

[0024] The number of carbon atoms constituting the alicyclic structure is preferably 4 or more, more preferably 5 or more, and preferably 30 or less, more preferably 20 or less, and particularly preferably 15 or less, per one alicyclic structure. When the number of carbon atoms constituting the alicyclic structure is within the above range, the inherent mechanical strength, heat resistance, and moldability of the alicyclic structure-containing polymer are highly balanced.

[0025] The ratio of the structural unit having an alicyclic structure in the alicyclic structure-containing polymer may be appropriately selected depending on the purpose of use, and is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight or more. When the ratio of the structural unit having an alicyclic structure in the alicyclic structure-containing polymer is within this range, the transparency and heat resistance of the resin are good.

[0026] Examples of the polymer containing an alicyclic structure include norbornene-based polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and hydrogenated products thereof. Among these, norbornene-based polymers are preferred because of their good transparency and moldability.

[0027] Examples of norbornene-based polymers and their hydrogenated products include ring-opening polymers of monomers having a norbornene structure and their hydrogenated products; addition polymers of monomers having a norbornene structure and their hydrogenated products. Examples of ring-opening polymers of monomers having a norbornene structure include ring-opening homopolymers of one type of monomer having a norbornene structure, ring-opening copolymers of two or more types of monomers having a norbornene structure, and ring-opening copolymers of a monomer having a norbornene structure and any monomer that can be copolymerized therewith. Examples of addition polymers of monomers having a norbornene structure include addition homopolymers of one type of monomer having a norbornene structure, addition copolymers of two or more types of monomers having a norbornene structure, and addition copolymers of a monomer having a norbornene structure and any monomer that can be copolymerized therewith. Examples of these polymers include the polymers disclosed in JP-A-2002-321302 and the like. Among these, a hydrogenated product of a ring-opening polymer of a monomer having a norbornene structure is particularly suitable from the viewpoints of moldability, heat resistance, low moisture absorption, dimensional stability and light weight.

[0028] Specific examples of norbornene-based polymers and hydrogenated products thereof include "ZEONOR" manufactured by Zeon Corporation; "ARTON" manufactured by JSR Corporation; and "TOPAS" manufactured by TOPAS ADVANCED POLYMERS.

[0029] A stretched film can be obtained by stretching a film to be stretched. The stretching method for obtaining a stretched film is not particularly limited. Examples of the stretching method include uniaxial stretching methods such as a method of uniaxially stretching a film in the longitudinal direction (longitudinal uniaxial stretching method) and a method of uniaxially stretching a film in the width direction (transverse uniaxial stretching method); biaxial stretching methods such as a simultaneous biaxial stretching method in which a film is stretched in the longitudinal direction and at the same time in the width direction, and a sequential biaxial stretching method in which a film is stretched in one of the longitudinal direction and the width direction and then stretched in the other direction; and a method of stretching a film in an oblique direction (oblique stretching method); and combinations thereof. The stretching ratio is preferably 1.1 times or more, more preferably 1.2 times or more, and is preferably 3 times or less, more preferably 2.5 times or less.

[0030] The stretched film of the present embodiment is preferably an obliquely stretched film. The obliquely stretched film is a film stretched by a stretching process including an oblique stretching method.

[0031] The direction of the slow axis of the stretched film is preferably neither parallel nor perpendicular to the width direction of the stretched film, but is oblique to the width direction of the stretched film. The direction of the slow axis of the stretched film can be appropriately determined depending on the shape and application of the packaging bag.

[0032] The stretched film used in the packaging bag may be a single-layer film having only the stretched film, or may be a multi-layer film having a functional layer provided on the stretched film. Examples of the functional layer include a gas barrier layer and a printed layer. The thickness of the functional layer is not particularly limited, and is not particularly limited as long as it can exert a desired function and does not inhibit the tearability of the stretched film when the packaging bag is opened.

[0033] <3. Packaging bag shape> A packaging bag according to one embodiment of the present invention includes a storage section, a sealing section, and a cut-off section that are made of a stretched film. In the packaging bag according to one embodiment of the present invention, at least a part of the film that constitutes the storage section has a first film as a stretched film. In such a packaging bag, the inner wall of the storage section of the packaging bag usually defines an internal space for storing an item.

[0034] The form of the packaging bag according to one embodiment of the present invention may take any form including the above-mentioned configurations of the storage section, the sealing section, and the cut-out section, but one preferred example is a form in which the storage section has a first film as a stretched film and a second film facing the first film and also as a stretched film, and the first film and the second film are laminated at the sealing section (first embodiment). Another preferred example of the form of the packaging bag is a form in which the storage section has a structure in which the first film is folded (second embodiment). Still another preferred example of the form of the packaging bag is a form in which the first film is arranged in a cylindrical shape in the storage section (third embodiment). The first to third embodiments will be described below.

[0035] <3.1. First embodiment> The packaging bag according to the first embodiment of the present invention has a storage section, a sealing section and a cut-off section, and the storage section has a first film as a stretched film and a second film opposite the first film and also as a stretched film, and has a structure in which the first film and the second film are laminated at the sealing section.

[0036] According to the first embodiment, by adjusting the orientation direction of the molecules of the polymer contained in the first film and the orientation direction of the molecules of the polymer contained in the second film, it is possible to obtain a packaging bag in which the opening direction and the size of the opening opening can be effectively controlled depending on the application of the packaging bag. Hereinafter, the orientation direction of the molecules of the polymer contained in the second film may be referred to as the orientation direction of the second film.

[0037] The packaging bag according to the first embodiment will be described with reference to the drawings. In the following description, unless otherwise specified, a plan view refers to a view of the first film side of the packaging bag viewed from a direction perpendicular to the outer surface of the first film.

[0038] Fig. 1(a) is a plan view showing a packaging bag according to a first embodiment, and Fig. 1(b) is a cross-sectional view of the packaging bag taken along line AA in Fig. 1(a). Fig. 2 is a diagram for explaining the orientation direction of a stretched film constituting the packaging bag in Fig. 1. Fig. 3 is a plan view showing a schematic configuration of the packaging bag shown in Fig. 1 after opening.

[0039] As shown in Figs. 1(a) and (b), the packaging bag 10 (10A) is composed of a first film 1a and a second film 1b, and includes a storage section 11 for storing an item, a sealing section 12 provided at an end of the storage section 11 to seal the storage section 11, and a cut section 13 provided at the sealing section 12. In Fig. 1(a), the cut section 13 is provided at the sealing section 12 located at the lateral end 11s of the storage section 11. The first film 1a and the second film 1b are stretched films. The packaging bag 10A has a structure in which the storage section 11 has the first film 1a and the second film 1b facing the first film 1a, and the first film 1a and the second film 1b are laminated at the sealing section 12. In the packaging bag 10A, the orientation direction x1 of the first film 1a is oblique to the height direction h from the bottom 11b to the top 11t of the storage section 11. In the packaging bag 10A, the shape of the storage section 11 when viewed perpendicularly to the main surface f1 of the first film is rectangular, and a sealing portion 12 is provided to seal the four sides of the rectangular storage section 11. In the packaging bag 10A, of the surfaces f1 and i1 of the first film, the surface that is disposed on the outer side of the packaging bag is the main surface. Similarly, of the surfaces f2 and i2 of the second film, the surface that is disposed on the outer side is the main surface. The surfaces i1 and i2 of each film form the inner wall surfaces of the storage section. In the packaging bag 10A, the inner wall of the storage section 11 defines an internal space S for storing an item.

[0040] As shown in Figs. 1(a) and 2, in the packaging bag 10A, the orientation direction x1 of the first film 1a and the orientation direction x2 of the second film 1b are the same. When such a packaging bag 10A is torn open by hand from the cut portion 13, the first film 1a of the storage section 11 can be torn along the orientation direction x1, as shown in Fig. 3. Meanwhile, the second film 1b of the storage section 11 can be torn along the orientation direction x2, which is the same direction as the orientation direction x1. Therefore, an opening can be formed in the orientation direction x1 of the first film from the cut portion 13 toward the top portion 11t of the storage section 11. As a result, the opening can be made smaller than when the packaging bag 10A is torn in the height direction h of the storage section 11 or in the width direction w of the storage section.

[0041] Fig. 4 is a plan view showing a schematic diagram of a packaging bag according to a first embodiment. Fig. 5 is a view for explaining the orientation direction of a stretched film constituting the packaging bag of Fig. 4. Fig. 6 is a plan view showing a schematic diagram of the shape of the packaging bag shown in Fig. 4 after opening. The packaging bag 10 (10B) shown in Figs. 4 to 6 has the same configuration as the packaging bag 10A described in Figs. 1 to 3, except that the orientation direction x1 of the first film 1a and the orientation direction x2 of the second film 1b are different.

[0042] As shown in Figs. 4 and 5, in the packaging bag 10B, the orientation direction x1 of the first film 1a is different from the orientation direction x2 of the second film 1b. In Figs. 4 and 5, the orientation direction x1 of the first film 1a is oblique to the height direction h of the storage section 11, and the orientation direction x2 of the second film 1b is perpendicular to the height direction h of the storage section 11 (parallel to the width direction w). When such a packaging bag 10B is opened by tearing it open by hand from the cut portion 13, as shown in Fig. 6, the first film 1a of the storage section 11 can be torn along the orientation direction x1. On the other hand, the second film 1b of the storage section 11 can be torn along the orientation direction x2, which is perpendicular to the height direction h of the storage section 11. Therefore, the shape of the opening can be a triangle in which the first film 1a side of the storage section 11 opens wider than the width direction w, and the second film 1b side of the storage section 11 opens in the width direction w. As a result, the opening can be made larger than when the first film side of the packaging bag is torn in the width direction, making it easier to remove the article from the first film side. Also, since the opening does not reach the bottom, the article stored in the packaging bag can be held within the storage section.

[0043] Not limited to the examples shown in Figures 1 to 6, according to the first embodiment, the opening direction and size of the opening opening of the packaging bag can be adjusted by adjusting the orientation direction of the first film and the orientation direction of the second film, thereby making it possible to produce a packaging bag in which the opening direction and size of the opening opening are controlled depending on the application of the packaging bag.

[0044] (Packaging bag structure) The packaging bag has a first film arranged in a storage section and a second film facing the first film, and has a structure in which the first film and the second film are laminated at a sealing section. Here, this includes not only a case in which the first film and the second film are laminated at the sealing section by being attached to each other via an adhesive or a pressure sensitive adhesive, but also a case in which the first film and the second film are fused and laminated by a thermal welding process.

[0045] As long as the storage section of the packaging bag has a structure including a first film and a second film, the packaging bag may have a bottom surface on at least one of the bottom side and the top side, or may not have a bottom surface, but it is preferable that the packaging bag does not have a bottom surface. In other words, the packaging bag is preferably a flat bag. This is because the packaging bag is easy to manufacture and can be highly versatile.

[0046] (Storage section) The storage section according to the first embodiment has a first film which is a stretched film and a second film which is a stretched film.

[0047] In the first embodiment, the first film arranged in the storage section has the orientation direction of the polymer molecules contained in the first film oblique to the height direction from the bottom to the top of the storage section. If the angle θ1 is an angle between the height direction h of the storage section and the orientation direction x1 of the first film, the angle θ1 is, for example, greater than 0°, preferably 10° or more, more preferably 20° or more, and even more preferably 25° or more. The angle θ1 is, for example, preferably 75° or less, and may be 60° or less, or may be 45° or less. Furthermore, the angle θ1 is, for example, preferably 115° or more, may be 120° or more, or may be 135° or more. Moreover, the angle θ1 is, for example, less than 180°, preferably 170° or less, more preferably 160° or less, and further preferably 165° or less. By setting the angle θ1 within the above range, when the packaging bag is torn open by hand from the cut edge, the first film can be torn along the molecular orientation direction, so that the opening on the first film side can be provided diagonally with respect to the height direction of the packaging bag and opened. The angle θ1 is an angle expressed with the bottom of the height direction h as 0° and the top as 180°. The angle θ1 is, for example, the angle represented by θ1 in FIG. 1(a).

[0048] The orientation direction of the second film in the storage section is not particularly limited and can be appropriately selected depending on the application of the packaging bag. The orientation direction of the second film may be, for example, an oblique direction with respect to the height direction of the storage section as shown in FIG. 1, or may be a perpendicular direction with respect to the height direction of the storage section as shown in FIG. 4, or may be a parallel direction with respect to the height direction of the storage section. In other words, when the angle formed by the orientation direction x2 of the second film with respect to the height direction h of the storage section is defined as angle θ2, the angle θ2 can be any angle between 0° and 180°. The angle θ2 is, for example, the angle represented by θ2 in FIG. 4.

[0049] In the first embodiment, the orientation direction of the first film and the orientation direction of the second film in the storage section can be appropriately selected depending on the application of the packaging bag and the items to be stored. For example, when the orientation direction of the first film and the orientation direction of the second film are the same, it is easy to provide an opening at an angle to the height direction of the packaging bag, and it is easy to separate the torn film. In addition, the opening can be made smaller the closer the cut portion formed in the packaging bag is to the end in the width direction or height direction of the packaging bag, so it can be used particularly preferably in applications where the opening of the packaging bag is required to be smaller than the width direction of the packaging bag.

[0050] Here, the "the orientation direction of the first film and the orientation direction of the second film are the same" includes not only the case where the orientation direction of the first film and the orientation direction of the second film are completely the same, but also the case where there is an error therebetween that does not impede the above-mentioned effect. Specifically, the angle between the orientation direction of the first film and the orientation direction of the second film can be within 0°±10°, 0°±5°, or 0°±3°.

[0051] For example, when the orientation direction of the first film and the orientation direction of the second film are different, the tear direction of the first film and the tear direction of the second film surface can be different when the packaging bag is torn from the cut portion, so that, for example, the opening of the packaging bag can be made large. Therefore, for example, while the second film side is in contact with an article, the first film side can be opened widely to remove the article.

[0052] When the orientation direction of the first film is different from the orientation direction of the second film, the angle between the orientation direction of the first film and the orientation direction of the second film is defined as angle θ3. The angle θ3 is, for example, greater than 10°, preferably 30° or more, and more preferably 45° or more. The angle θ3 is, for example, less than 180°, preferably 160° or less, and more preferably 150° or less. The angle θ3 is, for example, the angle represented by θ3 in FIG. 4.

[0053] In the packaging bag, whether the orientation direction of the first film is oblique to the height direction of the storage section can be confirmed, for example, by measuring the angle θ1. The angle θ1 can be measured from the slow axis of the first film. Specifically, it is as follows. Usually, the orientation direction of the polymer molecules contained in the film formed of a resin having a positive intrinsic birefringence is parallel to the slow axis of the film. Therefore, when the first film is composed of a film formed of a resin having a positive intrinsic birefringence, the angle θ1 of the orientation direction of the first film with respect to the height direction of the storage section can be measured as the angle of the slow axis of the stretched film constituting the first film with respect to the height direction of the storage section. On the other hand, usually, the orientation direction of the polymer molecules contained in the film formed of a resin having a negative intrinsic birefringence is perpendicular to the slow axis of the film. Therefore, when the first film is composed of a film formed of a resin having a negative intrinsic birefringence, the angle θ1 of the orientation direction of the first film with respect to the height direction of the storage section can be measured as the angle of the direction perpendicular to the slow axis of the stretched film constituting the first film with respect to the width direction with respect to the height direction of the storage section. The slow axis direction can be measured using a polarizing microscope (for example, "BX51" manufactured by Olympus Corporation). The angle θ2 can be measured in the same manner as the angle θ1. The angle θ3 can be calculated by measuring the angles θ1 and θ2 and based on the measured values.

[0054] The shape of the storage section is appropriately selected according to the application of the packaging bag, and is not limited to a specific shape. The shape of the storage section when the packaging bag is viewed from a direction perpendicular to the main surface of the first film may be, for example, a shape surrounded by straight lines, a shape surrounded by curves such as arcs and wavy lines, or a shape surrounded by the above-mentioned multiple types of lines. More specific shapes include a circular shape, an elliptical shape, a semicircular shape, a semielliptical shape, a triangular shape, a rectangular shape, a polygonal shape with pentagons or more, a polygonal shape with rounded corners, and a shape combining these. Furthermore, the above-mentioned figures may also be represented by zigzag lines or wavy lines. The shape of the storage section when the packaging bag is viewed from a direction perpendicular to the first film may usually be the shape of the storage section surrounded by the sealing section.

[0055] In the present embodiment, the shape of the storage section when the packaging bag is viewed from a direction perpendicular to the first film is preferably rectangular, because this makes it easy to design the opening direction and opening opening, and also makes it easy to manufacture the packaging bag.

[0056] (Sealing part) The sealing part is provided at the end of the storage part and seals the storage part. The sealing part is usually formed by bonding two stretched films together. The sealing part may be formed by bonding two stretched films together by heat welding, or may be formed by bonding two stretched films together by providing an adhesive layer between them.

[0057] The position of the sealing part in the packaging bag can be appropriately selected depending on the shape of the packaging bag. For example, when the shape of the storage part is rectangular when viewed from the vertical direction of the first film, the sealing parts can be provided on the four sides around the storage part.

[0058] The adhesive and pressure-sensitive adhesive used in the sealing portion may be the same as those used in general packaging bags.

[0059] (Cutting edge) The cut portion is provided in the sealing portion. The cut portion is also called a "notch." The cut portion is provided in a position in the packaging bag where the closed storage portion can be opened, and is preferably provided in the sealing portion located at the top end or side end of the storage portion. The cut portion may be provided in the sealing portion located at the bottom end of the storage portion, but is preferably not provided.

[0060] The packaging bag may have at least one cut, and may have only one or more cuts. Examples of the shape of the cut include an I-shape, a V-shape, and a U-shape.

[0061] <3.2. Second embodiment> A packaging bag according to a second embodiment of the present invention includes a storage section, a sealing section, and a cut-out section, and the storage section has a structure formed by folding a first film. In this packaging bag, for example, the first film, which is a sheet of stretched film, is folded at a fold line, and the first film has a first region and a second region with the fold line as a boundary.

[0062] According to the second embodiment, the first film has a folded structure in which the molecular orientation direction is diagonal to the height direction of the storage section, so that a packaging bag can be made in which the opening direction and size of the opening opening are controlled by the orientation direction of the first film and the position of the cut end portion.

[0063] Furthermore, since the packaging bag according to the second embodiment has a structure formed by folding one first film, it can be efficiently manufactured, for example, by folding and processing a continuous obliquely stretched film along the flow direction in a packaging bag manufacturing device. Furthermore, this packaging bag can create a difference in the orientation directions of the films (first region and second region) arranged on the front and back of the packaging bag by folding one first film.

[0064] The packaging bag according to the second embodiment will be described with reference to the drawings. Fig. 7(a) is a plan view showing a schematic diagram of another example of the packaging bag according to the first embodiment of the present invention, and Fig. 7(b) is a cross-sectional view of the packaging bag in Fig. 1(a) taken along line AA. Fig. 8 is a development view of a stretched film constituting the packaging bag shown in Fig. 7. Fig. 9 is a plan view showing a schematic diagram of the packaging bag shown in Fig. 7 after opening. The packaging bag 20 (20A) shown in Figs. 7 to 9 has the same configuration as the packaging bag 10A described in Figs. 1 to 3, except for the points described below.

[0065] The packaging bag 20A shown in Figures 7(a) and 7(b) is configured by folding a first film 2a, which is a single stretched film. Specifically, as shown in Figure 8, the first film 2a is folded in half in the width direction w of the packaging bag 20A, and sealing portions 22 are provided on both side ends of the folded fold line 24 and on the end opposite the fold line 24. More specifically, the packaging bag 20A has a rectangular storage section 21 when viewed from a direction perpendicular to the first film 2a, and sealing portions 22 are provided so as to seal three sides of the rectangular storage section 21.

[0066] As shown in Fig. 7(a), Fig. 7(b) and Fig. 8, the packaging bag 20A has the first film 2a, which is a sheet of stretched film, folded at the fold line 24. When the fold line 24 is used as a boundary to define a first region e1 on one side and a second region e2 on the other side, the orientation direction x1 of the first region e1 and the orientation direction x2 of the second region e2 are opposite directions. Specifically, as shown in Fig. 8, before the first film 2a constituting the packaging bag 20A is folded, the orientation direction x1 of the first region e1 and the orientation direction x12 of the second region e2 are the same direction. By folding such a first film 2a in a direction that is the width direction w of the packaging bag 20A, the vector of the orientation direction x12 of the second region e2 is opposite directions, so that the orientation direction x1 of the first region e1 and the orientation direction x3 of the second region e2 are opposite directions with the fold line 24 as a boundary. When such a packaging bag 20A is opened by tearing it by hand from the cut portion, the first region e1 of the storage section 21 is torn along the orientation direction x1 as shown in Fig. 9. Meanwhile, the second region e2 of the storage section 21 is torn along the orientation direction x3, which is the opposite direction to the orientation direction x1. Therefore, the shape of the opening is, for example, an isosceles triangle having an axis of symmetry in the width direction w of the storage section 21. In the packaging bag 20A, an opening opening can be formed on the first region e1 side or the second region e2 side of the storage section 21, so that the packaging bag 20A can be made such that the article stored in the packaging bag 20A can be easily taken out from the first region e1 side or the second region e2 side.

[0067] Fig. 10 is a plan view diagrammatically showing another example of the packaging bag according to the first embodiment of the present invention. Fig. 11 is a development view of a stretched film constituting the packaging bag shown in Fig. 11. Fig. 12 is a plan view diagrammatically showing an opening of the packaging bag shown in Fig. 11. The packaging bag 20 (20B) shown in Figs. 10 to 12 has the same configuration as the packaging bag 20A described in Figs. 7 to 9, except for the points described below.

[0068] The packaging bag 20B shown in Fig. 10 is configured by folding a first film 2a, which is a single stretched film, and has a structure in which the distance in the height direction h of the storage section 21 is long. In addition, the sealing section 22 facing the folding line section 24 is configured to have a plurality of cut portions 23a, 23b, and 23c provided in the sealing section 22 provided at the lateral end of the storage section 11. The interval I between the cut portions 23a, 23b, and 23c is adjusted, for example, as follows. As shown in Fig. 11, when the angle between the orientation direction x1 of the first region e1 and the height direction of the storage section 21 is the angle θ1, and the width of the storage section 21 is W, the interval I between the cut portions is calculated by the following formula (1). I = 2W × tan θ1 When such a packaging bag 20B is opened by tearing the incision portion 23a by hand, the first region e1 and the second region e2 can be opened continuously up to the position of the incision portion 23b, as shown in FIG. 12. Moreover, by tearing the incision portion 23b by hand, the first region e1 and the second region e2 can be opened continuously up to the position of the incision portion 23c. Furthermore, by tearing the incision portion 23c by hand, the first region e1 and the second region e2 can be opened continuously up to the vicinity of the bottom. As a result, in the packaging bag 20B, the first film 2a constituting the first region e1 and the second region e2 of the storage section 21 can be removed in a spiral shape in stages to take out the article.

[0069] The packaging bag according to the second embodiment will be described in detail below, but matters not described are the same as those described for the packaging bag according to the first embodiment.

[0070] In the second embodiment, the orientation direction of the first film is an oblique direction with respect to the height direction of the storage section, and can be the same as the orientation direction of the first film of the packaging bag according to the first embodiment. In other words, if the angle of the orientation direction of the first film with respect to the oblique direction with respect to the height direction of the storage section is θ1, the angle θ1 can be the same as the angle θ1 in the first embodiment. In particular, in the second embodiment, the angle θ1 is preferably, for example, 15° or more, more preferably 20° or more, and particularly preferably 30° or more. In addition, the angle θ is, for example, preferably 75° or less, more preferably 60° or less, and particularly preferably 45° or less. By setting the angle θ1 according to the second embodiment in the above range, it is possible to easily control the opening direction and the size of the opening opening of the packaging bag when the packaging bag is torn by hand. In addition, by setting the angle θ1 to be equal to or more than the above lower limit, the tearability of the film can be improved. Furthermore, by having the angle θ1 be equal to or less than the upper limit, the articles contained therein can be easily held even after the packaging bag is torn, and damage to the contained articles can be effectively prevented.

[0071] The position of the sealing part in the packaging bag can be appropriately selected depending on the shape of the packaging bag. For example, in the second embodiment, since the packaging bag is composed of one stretched film, for example, when the shape of the storage part when viewed from the vertical direction of the first film is rectangular, the sealing part can be provided on three sides around the storage part.

[0072] <3.3. Third embodiment> The packaging bag according to the third embodiment of the present invention has a storage section, a sealing section, and a cut opening section, and has a structure in which a first film is arranged in a cylindrical shape in the storage section.

[0073] According to the third embodiment, the orientation direction of the tubularly arranged first film is oblique to the height direction of the storage section, so that, for example, when the packaging bag is torn by hand from the cut opening, the stretched film arranged on the side of the tubular bag can be removed in a spiral manner.

[0074] A packaging bag according to a third embodiment will be described with reference to the drawings. FIG. 13 is a perspective view showing an example of a packaging bag according to a third embodiment, and FIG. 14 is a view for explaining the opening direction and the opening of the packaging bag in FIG. 13. The packaging bag 30 is made of a stretched film 3a containing a polymer, and includes a storage section 31, a sealing section 32 provided at an end of the storage section 31 to seal the storage section 31, and a plurality of cut sections 33a, 33b, and 33c provided at the sealing section 32. The packaging bag 30 has a structure in which the first film 3a is arranged in a cylindrical shape in the storage section 31. Specifically, the packaging bag 30 has a structure in which the bottom section 31b and the top section 31t are two bottom surfaces, and the first film 3a is arranged on the side surface. In the packaging bag 30, the orientation direction of the molecules of the polymer contained in the first film 3a is an oblique direction x1 with respect to the height direction h from the bottom section 31b to the top section 31t of the storage section 31.

[0075] When such a packaging bag 30 is opened by tearing it by hand from the cut opening 33a, the first film 3a can be torn and opened up to the position of the cut opening 33b, as shown in Fig. 14. Moreover, by tearing the cut opening 33b by hand, the first film 3a can be torn and opened further up to the position of the cut opening 33c. Furthermore, by tearing the cut opening 33c by hand, the first film 3a can be torn and opened up to the vicinity of the bottom 31b. As a result, in the packaging bag 30, the first film 3a arranged in a cylindrical shape in the storage section 31 can be spirally removed in stages to take out an article.

[0076] The packaging bag according to the third embodiment will be described in detail below, but matters not described are the same as those described for the packaging bag according to the first embodiment.

[0077] The storage section usually has a bottom surface at its bottom and top, and the first film is arranged in a cylindrical shape on the side surface of the storage section. The shape of the bottom surface of the bottom and top of the storage section is typically circular, but may also include an elliptical shape or a polygonal shape. The bottom and top of the storage section may be made of a film that constitutes the first film, or may be made of a film different from the stretched film that constitutes the first film.

[0078] In the third embodiment, for example, a cylindrical shape can be obtained by bonding opposing sides of a single stretched film together by heat welding or the like to provide a sealed portion.

[0079] <4. Modifications> In the above-mentioned example, the example having the storage section, the sealing section, and the cut-out section has been described, but the present invention may also include a packaging bag having the following configuration, for example. That is, A packaging bag made of a stretched film containing a polymer, the packaging bag comprising: a storage section for storing an item; a sealing section provided at an end of the storage section for sealing the storage section; and an opening provided at the end of the storage section and communicating with a storage space, The storage section has a first film as the stretched film, A packaging bag in which the orientation direction of the polymer molecules contained in the first film is oblique to the height direction from the bottom to the top of the storage section.

[0080] In the above-mentioned modified example, the cut portion does not necessarily have to be provided, but usually, after an article is stored through the opening, the opening is sealed and then the cut portion is provided.

[0081] The position of the opening can be appropriately selected depending on the application of the packaging bag, but it is preferable to provide the opening at the top or side of the packaging bag.

[0082] As a modified example of the packaging bag, for example, an opening may be provided in place of a part of the sealed portion of the packaging bag according to the above-described first to third embodiments.

[0083] Regarding the modified examples, matters that are not described may be the same as those described as the configuration of the packaging bag according to the first and second embodiments described above.

[0084] <5. Manufacturing method> The method for producing the packaging bag according to an embodiment of the present invention is not particularly limited, and the bag may be produced by a known method for producing a packaging bag. For example, a method may be used in which stretched films are prepared, the stretched films are layered according to the desired shape of the bag, the ends are bonded together by heat welding or an adhesive to form a sealing portion, and a cut portion is provided in the sealing portion.

[0085] The stretched film used in the manufacturing method of the packaging bag may be a uniaxially stretched film, a biaxially stretched film, or an obliquely stretched film. Among them, an obliquely stretched film is preferable. This is because the use of an obliquely stretched film can reduce the loss of the film. In addition, when the obliquely stretched film is continuously processed, the tear angles can be set to different angles on the front and back by folding one side and overlapping the film, rather than fusing two types of film. Therefore, when manufacturing the packaging bag according to the second embodiment, it is particularly preferable to use an obliquely stretched film.

[0086] In addition, the stretched film used in the manufacturing method of the packaging bag is preferably a long film. Here, a "long" film refers to a film having a length of 5 times or more, preferably 10 times or more, and specifically refers to a film having a length sufficient to be wound into a roll for storage or transportation. There is no particular upper limit to the length of the film, and it can be, for example, 100,000 times or less, the width.

[0087] The conditions for heat welding when forming the sealing portion can be appropriately set depending on the type of polymer contained in the stretched film. The packaging bag according to one embodiment of the present invention can be produced using a known packaging machine.

[0088] <6. Uses of packaging bags> The packaging bag according to one embodiment of the present invention can be used as packaging for products in a variety of fields, such as food, medicine, precision parts, daily necessities, etc. EXAMPLES

[0089] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the examples shown below, and can be modified and carried out as desired without departing from the scope of the claims of the present invention and the scope of equivalents thereto.

[0090] [Production Example 1] Pellets of an alicyclic olefin resin containing a norbornene polymer (ZEONOR manufactured by Zeon Corporation; glass transition temperature 126°C) were dried at 100°C for 5 hours and fed to an extruder. The pellets were melted in the extruder at a molten resin temperature of 270°C, and the molten resin was extruded from a T-die onto a casting drum in the form of a sheet and cooled to obtain a pre-stretched substrate film having a thickness of 70 μm.

[0091] The obtained pre-stretched substrate film was fed to an oblique stretching device and stretched at a stretching temperature of 143° C. and a stretch ratio of 1.5 times at an oblique angle of 45° to a thickness of 47 μm to obtain an obliquely stretched film.

[0092] [Production Example 2] The pre-stretched substrate film prepared in the same manner as in Production Example 1 was fed to an oblique transverse stretching device, and stretched to a thickness of 47 μm at a stretching temperature of 143° C. and a stretch ratio of 1.5 to obtain a transversely stretched film.

[0093] [Example 1] The above-mentioned obliquely stretched film was cut to a size of 300 mm x 200 mm to prepare two pre-processed films. At this time, the obliquely stretched film was cut so that the conveying direction of the film was 300 mm. As shown in Figures 1(a) and 2, the obtained pre-processed films were overlapped so that the orientation direction of the first film was the same as that of the second film. Then, the four sides of the overlapped processed film were heat-sealed under the conditions of a sealing temperature of 220°C, a pressure of 0.3 MPa, and a sealing time of 1 second to provide a sealing portion. Next, as shown in Figure 1(a), a cut was made in the sealing portion provided at the side end of the storage portion to obtain a packaging bag. It was confirmed that the obtained packaging bag was opened along the molecular orientation direction by tearing the packaging bag by hand from the cut portion, as shown in Figure 3.

[0094] [Example 2] The obliquely stretched film and the transversely stretched film were cut to a size of 300 mm x 200 mm to prepare a pre-processed film. At this time, each stretched film was cut so that the conveying direction of the film was 300 mm. As shown in Figs. 4 and 5, the obtained pre-processed films were overlapped so that the orientation direction of the first film was oblique to the height direction of the packaging bag and the orientation direction of the second film was perpendicular to the height direction of the packaging bag. Then, the four sides of the overlapped processed film were heat-sealed under the same conditions as in Example 1 to provide a sealing portion. Next, as shown in Fig. 4, a cut portion was provided in the sealing portion provided at the side end of the storage portion to obtain a packaging bag. It was confirmed that the obtained packaging bag was opened along the molecular orientation direction by tearing the packaging bag by hand from the cut portion, as shown in Fig. 6. [Explanation of symbols]

[0095] 1a, 1b, 2a, 3a Stretched film 10, 10A, 10B, 10C, 10D, 20, 20A, 20B, 30 packaging bags 11, 21, 31 Storage area 12, 22, 32 Sealing part 13, 23a, 23b, 23c, 33a, 33b, 33c Cutting section 11b, 21b, 31b Bottom of storage area 11s, 21s, 31t Top of storage area x1: Molecular orientation of the first film x2 Molecular orientation of the second film h Height of storage compartment

Claims

1. A storage section configured by a stretched film containing a polymer and configured to store an item; a sealing portion provided at an end of the storage portion and sealing the storage portion; A packaging bag having a cut portion provided in the sealing portion, The storage section has a first film as the stretched film, A packaging bag in which the orientation direction of the polymer molecules contained in the first film is oblique to the height direction from the bottom to the top of the storage section.

2. The packaging bag according to claim 1 , wherein the cut portion is provided in the sealing portion located at the top end or a side end of the storage portion.

3. the storage section has a second film that faces the first film and is a stretched film; The packaging bag according to claim 1 , wherein the first film and the second film have a laminated structure at the sealing portion.

4. The packaging bag according to claim 3 , wherein the packaging bag is a flat bag.

5. The packaging bag according to claim 3 , wherein the storage section has a rectangular shape when viewed from a direction perpendicular to the main surface of the first film.

6. The angle θ between the orientation direction of the polymer molecules contained in the first film and the height direction of the storage section. １ The packaging bag according to claim 3, wherein the angle is greater than 0° and less than 75°, or greater than 115° and less than 180°.

7. The packaging bag according to claim 3 , wherein an orientation direction of the molecules of the polymer contained in the first film is different from an orientation direction of the molecules of the polymer contained in the second film.

8. The packaging bag according to claim 1 , wherein the storage section has a structure in which the first film is folded.

9. The packaging bag according to claim 1 , wherein the first film is arranged in a cylindrical shape in the storage section.

10. The packaging bag according to claim 9 , wherein the sealing portion located at the side end of the storage portion is provided with a plurality of cut portions.

11. The packaging bag according to any one of claims 1 to 10, wherein the packaging bag is made of a multilayer film including the stretched film.

Images