Film, packaging container, packaging container containing content, and film manufacturing method

Abstract

To provide a film of which an end of a processed part can be prevented from torn when internal pressure increases and of which a breaking part breaks stably, a packaging container, a packaging container containing content, and a film manufacturing method.SOLUTION: A film, which is used as at least a part of a packaging container, includes a base material layer, a sealing layer laminated on the base material layer, and a linear processed part formed on the base material layer and forming a breaking part that breaks when internal pressure increases. The processed part is formed longer in one direction and has multiple straight pars lined up in the longitudinal direction, and the width in the short direction of the straight part at least at one of the opposing end parts of the adjacent straight parts is wider than the smallest width in the short direction closer to the center than the end parts of the straight pars.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a film for containing contents, a packaging container, a packaging container containing contents, and a method for manufacturing the film. [Background technology]

[0002] Containers that contain contents and are sealed to heat the contents in a microwave oven have been known for some time. However, when the contents of such containers are heated in a microwave oven, the internal pressure increases. For this reason, containers equipped with a means for automatically releasing steam and reducing the internal pressure during microwave heating are also known.

[0003] For example, Patent Document 1 discloses a cup container and film that can release water vapor when heated in a microwave oven by providing a breakable portion in the lid with non-oriented portions arranged opposite each other across an oriented portion of a crystalline stretch-oriented film. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7032092 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned technology, when the internal pressure increases during microwave heating, both the base layer and the seal layer of the film at the rupture portion rupture, releasing water vapor. However, because the shape of the end of the processed portion is unstable, tears may occur at the end of the processed portion, preventing the rupture portion from receiving the stress necessary for rupture. As a result, only the base layer at the rupture portion ruptures, leaving the seal layer, and the rupture portion may not rupture.

[0006] Therefore, the present invention aims to provide a film, a packaging container, a packaging container containing contents, and a method for manufacturing a film that prevents tearing at the end of the processed portion when the internal pressure increases and ensures that the breaking portion breaks stably. [Means for solving the problem]

[0007] According to one aspect of the present invention, the film is used for at least a part of a packaging container, and comprises a base layer, a sealing layer laminated to the base layer, and a linear processed portion formed on the base layer to form a breaking portion that breaks when internal pressure increases, the processed portion is formed long in one direction and has a plurality of linear portions lined up in the longitudinal direction, and the width in the short direction of at least one of the opposing ends of adjacent linear portions is greater than the smallest width in the short direction closer to the center than the end of the linear portion. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a film, a packaging container, a packaging container containing contents, and a method for manufacturing a film that prevents tearing of the end of the processed portion when the internal pressure increases and ensures that the breaking portion breaks stably. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a plan view showing the configuration of a packaging container containing contents according to an embodiment of the present invention, with part of the lid omitted. [Figure 2] FIG. 10 is a perspective view schematically showing the configuration of another example of a packaging container containing contents. [Figure 3] FIG. 3 is a cross-sectional view showing the configuration of a film used in the packaging container containing the contents. [Figure 4] FIG. 4 is a cross-sectional view showing the configuration of another example of a film used in the packaging container containing the same content. [Figure 5] 3 is an explanatory diagram showing the configuration of a processing unit used in the packaging container containing the same content, and showing an example of the flow of a manufacturing method. FIG. [Figure 6] 10A and 10B are explanatory diagrams showing the configuration of another example of a processing section used in the same container containing the contents, and showing an example of the flow of a manufacturing method. [Figure 7] FIG. 2 is an explanatory diagram showing an example of the evaluation results of an evaluation test of the packaging container containing the same contents. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the structure of a content-containing packaging container 1 using a film 3 according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view showing the configuration of a content-filled packaging container 1 according to an embodiment of the present invention, with a portion of the lid 12 (film 3) omitted. FIG. 2 is a perspective view schematically showing the configuration of another example of the content-filled packaging container 1. FIG. 3 is a cross-sectional view showing the configuration of the film 3 (lid 12) used in the content-filled packaging container 1, and FIG. 4 is a cross-sectional view showing the configuration of another example of the film 3 (lid 12) used in the content-filled packaging container 1. FIG. 5 is an explanatory diagram showing the configuration of a processed section 12a used in the content-filled packaging container 1 and an example of the flow of a manufacturing method. FIG. 6 is an explanatory diagram showing the configuration of another example of the processed section 12a used in the content-filled packaging container 1 and an example of the flow of a manufacturing method. FIG. 7 is an explanatory diagram showing an example of the evaluation results of an evaluation test of the content-filled packaging container 1.

[0011] The content-filled packaging container 1 comprises packaging containers 2, 2A and content 100 contained in the packaging containers 2, 2A. The content-filled packaging container 1 is a container for microwave heating in which the content is heated in a microwave oven. Here, the content 100 is something that contains moisture and is heated in a microwave oven, and includes, for example, food that is heated and cooked in a microwave oven, and items such as hand towels that are heated in a microwave oven.

[0012] Such packaging containers 2, 2A either use a film 3 having a processed portion 3a formed thereon as in the packaging container 2 shown in Fig. 1, or are formed from a film 3 having a processed portion 3a formed thereon as in the packaging container 2A shown in Fig. 2. The packaging containers 2, 2A are formed so that when the internal pressure increases as a result of heating the contents 100 in a microwave oven, the processed portion 3a breaks, forming a steam vent and allowing steam to escape through the steam vent.

[0013] As a specific example, as shown in FIG. 1, a packaging container 2 includes a container body 11 and a lid 12 formed of a film 3 that seals the container body 11.

[0014] As shown in FIG. 1, the container body 11 is a bottomed container capable of accommodating the contents 100. The container body 11 is a cup-shaped, dish-shaped, tray-shaped, or other container. The container body 11 is formed, for example, in a cylindrical or polygonal shape. In this embodiment, the container body 11 is, for example, a rectangular container that is long in one direction. The container body 11 includes a body 21, a bottom 22, and a flange 23. The container body 11 is formed, for example, from a resin material, specifically, polypropylene (PP) or polystyrene (PS). The container body 11 is formed by vacuum forming or pressure forming.

[0015] The lower end of the body 21 is closed by the bottom 22, and the upper end is open where the flange 23 is integrally formed. The body 21 is, for example, integrally continuous with the bottom 22 and the flange 23, and the width of the body 21 gradually decreases from the flange 23 side toward the bottom 22.

[0016] The bottom 22 is formed integrally with the lower end of the body 21. The bottom 22 is formed in a flat plate shape. For example, the center of the bottom 22 may protrude further toward the flange 23 than the outer edge.

[0017] The flange 23 is formed, for example, integrally with the upper end (opening end) of the body portion 21. The flange 23 is formed in an annular shape extending from the upper edge of the body portion 21 along the outer circumferential shape of the body portion 21 in a direction perpendicular to or intersecting the axial direction of the body portion 21. For example, the flange 23 is formed in a flat plate shape, and the lid 12 is heat-sealed to the flange 23. The portion of the lid 12 that is heat-sealed to the flange 23 forms a sealed portion.

[0018] The lid 12 is formed from a film 3. The lid 12 is formed so as to be heat-sealable, for example, to a flange 23. As such, one example of the packaging container 2 is a so-called tray container in which the lid 12 is heat-sealed to the container body 11 as a top seal.

[0019] Next, as another example, a packaging container 2A will be described. As another example, as shown in Fig. 2, the packaging container 2A used for the content-filled packaging container 1 is formed into a bag or pouch shape by folding one sheet of film 3 and heat-sealing the edges, or by stacking two or more sheets of film 3 and heat-sealing the edges. The packaging container 2A is formed into a rectangular bag or pouch shape, and has a sealed portion 2a formed by heat-sealing two or more sides. Note that the packaging container 2A may also be formed into a circular bag shape, and have a sealed portion 2a that is heat-sealed in an annular shape.

[0020] As described above, the film 3 is used as a lid 12 as part of the packaging container 2, or one or more sheets are heat-sealed into a bag to form a packaging container 2A.

[0021] Next, the film 3 used in such packaging containers 2, 2A will be described. As shown in Figs. 1 to 4, the film 3 is formed of a multilayer film having a base layer 31 on the outer surface side. The film 3 has a processed portion 3a in a portion thereof. When a plurality of films 3 are used in the packaging container 2A, the processed portion 3a is formed in any one of the films 3.

[0022] 3, the film 3 includes a base layer 31, an adhesive layer 32, and a seal layer 33. Furthermore, for example, as shown in FIG. 4, the film 3 may have one or more intermediate layers 34 that form part of the base layer 31. In other words, the layer structure of the film 3 is not limited to this, and can be appropriately set as long as it has two or more layers including at least the base layer 31 and the seal layer 33.

[0023] The base layer 31 includes an orientation relaxation portion 31a formed by heating a portion of the base layer 31 to a predetermined temperature near the melting point or higher. The orientation relaxation portion 31a constitutes a part of the processed portion 3a.

[0024] The substrate layer 31 is a crystalline biaxially oriented film. The substrate layer 31 may be, for example, a general-purpose biaxially oriented film such as a biaxially oriented PET film, a biaxially oriented nylon film, or a biaxially oriented PP film, or a composite film of these. Other suitable examples of the substrate layer 31 include biaxially oriented PBT film, biaxially oriented PET / PBT blend film, biaxially oriented NY film laminated with PET, biaxially oriented PVA film, biaxially oriented EVOH film, or other biaxially oriented films made of a single barrier resin, as well as coextruded biaxially oriented films having a barrier resin such as PP / EVOH / PP, NY / EVOH / NY, or NY / MXD-NY / NY in the intermediate layer 34. Other suitable substrate layer 31 films include those obtained by coating a general-purpose biaxially oriented film with a PVA-, PVDC-, or PAA-based barrier resin, hybrid-coated films in which inorganic materials are dispersed in the aforementioned barrier resins, and transparent inorganic vapor-deposited films in which silica, alumina, or the like is vapor-deposited.

[0025] The orientation-relaxed portions 31a are formed by heating the base material layer 31 to a predetermined temperature or higher near the melting point to relax the orientation or eliminate the orientation. That is, the orientation-relaxed portions 31a are formed by amorphization. When the base material layer 31 has an intermediate layer 34, the orientation-relaxed portions 31a may be formed in the base material layer 31 and the intermediate layer 34. As a result, the base material layer 31 of the film 3 has orientation-relaxed portions 31a heated to a predetermined temperature or higher near the melting point in a part of the orientation-relieved portions 31b that have orientation and are not heated to a predetermined temperature or higher near the melting point. The predetermined temperature near the melting point differs depending on the base material layer 31, but is at least a temperature that relaxes the orientation and allows the tensile modulus and breaking elongation of the orientation-relaxed portions 31a and the orientation-relieved portions 31b to have the desired relationship.

[0026] The method of heating the base layer 31 to form the orientation relaxing portions 31a in the base layer 31 is, for example, laser beam heating.

[0027] For example, laser beam heating has the advantage of being able to heat the base material layer 31. Note that if the base material layer 31 used has poor laser beam absorption and it is difficult to form the orientation relaxed portions 31a by laser beam heating, a laser beam absorbing material that improves the laser beam absorption of the base material layer 31 may be blended into the material of the base material layer 31 in advance, or the base material layer 31 may be coated with the laser beam absorbing material.

[0028] As for the type of laser beam, it is preferable to use a carbon dioxide gas laser, since many of the resin materials used in the base layer 31 have relatively high absorption. The laser beam absorbent can be selected appropriately depending on the type of laser beam. These heating methods can be selected appropriately depending on the material of the base layer 31 to be used, etc.

[0029] Furthermore, whether the orientation relaxation portions 31a are properly formed or not can be determined by inspecting the formed base material layer 31. This inspection method can be performed using X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), crystallinity measurement by DSC (differential scanning calorimetry), or an orientation viewer using a polarizing plate.

[0030] The adhesive layer 32 can be appropriately selected from among general dry lamination adhesives for food use. However, since the packaging containers 2, 2A are used to heat the contents 100 in a microwave oven, the adhesive layer 32 is preferably heat resistant.

[0031] The sealing layer 33 is formed of a sealant film, such as an unstretched low-density polyethylene (LDPE) film, an unstretched linear low-density polyethylene (LLDPE) film, an unstretched polypropylene (PP) film, or an unstretched polyethylene terephthalate film.

[0032] Next, we will explain the processed portion 3a formed in the film 3. The processed portion 3a is formed in a part of the film 3, and has a rupture portion 3b that ruptures due to an increase in internal pressure, and this rupture portion 3b forms a steam port through which steam escapes. As a specific example, the processed portion 3a is formed long in one direction and is composed of multiple orientation relaxation portions 31a formed at predetermined intervals.

[0033] The alignment portions 31b between the alignment relaxation portions 31a form the broken portions 3b. The alignment relaxation portions 31a are formed long in one direction along the arrangement direction of the alignment relaxation portions 31a. In addition, in the lateral direction perpendicular to the longitudinal direction of the alignment relaxation portions 31a, the width of at least one end of adjacent alignment relaxation portions 31a is larger than the minimum width of the portion closer to the center (middle portion) than the end. As a specific example, the alignment relaxation portion 31a has a straight portion 31a1 extending in one direction and a wide portion 31a2 formed at an end facing the end of the straight portion 31a1 of the adjacent alignment relaxation portion 31a. The wide portion 31a2 has a dimension (width) larger than the dimension (width) in the direction (lateral direction) perpendicular to the extension direction (longitudinal direction) of the straight portion 31a1. For example, when an orientation relaxation section 31a is adjacent to another orientation relaxation section 31a at both ends in the longitudinal direction, a wide section 31a2 is formed at both ends of the orientation relaxation section 31a, and when an orientation relaxation section 31a is adjacent to another orientation relaxation section 31a at one end in the longitudinal direction and is not adjacent to another orientation relaxation section 31a at the other end in the longitudinal direction, a wide section 31a2 is formed at least at the end adjacent to another orientation relaxation section 31a.

[0034] For example, the straight portion 31a1 is formed by laser processing so that the dimension in the short direction of the straight portion 31a1 is constant. Note that due to the characteristics of laser processing, a constant value is selected as the set value (target value) for the dimension in the short direction of the straight portion 31a1, but there is variation in the actually measured value of the processed straight portion 31a1, and it is allowed that the dimensions are partially different. Such a straight portion 31a1 is formed by scanning laser light linearly over a predetermined distance on the film 3. Hereinafter, the straight portion 31a1 may also be referred to as the first laser processing portion. Here, when a wide portion 31a2 is formed at the end of the straight portion 31a1, the straight portion 31a1 means the region excluding the wide portion 31a2, that is, the region on the center side in the longitudinal direction rather than the wide portion 31a2.

[0035] The wide portion 31a2 is formed at the end of the straight portion 31a1 and is arranged to face the wide portion 31a2 formed in another orientation relaxation portion 31a with a predetermined interval. Between the opposing wide portions 31a2 of adjacent orientation relaxation portions 31a is the orientation portion 21b, which forms the break portion 3b. The wide portion 31a2 is formed, for example, by extending from the end of the straight portion 31a1 at least in one of the short directions of the straight portion 31a1. Specifically, as shown in FIG. 5, the wide portion 31a2 extends from the end of the straight portion 31a1 in both short directions of the straight portion 31a1, or as shown in FIG. 6, the wide portion 31a2 extends from the end of the straight portion 31a1 in one short direction of the straight portion 31a1.

[0036] The wide portion 31a2 is formed with a dimension (width) larger than the minimum dimension among the dimensions (widths) in the short direction of the straight portion 31a1 in the short direction of the straight portion 31a1. Hereinafter, the minimum dimension of the straight portion 31a1 in the short direction of the straight portion 31a1 will be described as the minimum width WA, and the dimension of the wide portion 31a2 will be described as the width WB.

[0037] The width WB of the wide portion 31a2 is larger than 1 times and less than or equal to 2 times the minimum width WA of the straight portion 31a1 (WA < WB < 2WA). Preferably, the width W2 of the wide portion 31a2 is greater than or equal to 1.05 times and less than or equal to 1.6 times the minimum width W1 of the straight portion 31a1 (1.05WA < WB < 1.6WA).

[0038] The relative angle between the linear portion 31a1 and the wide portion 31a2 is preferably in the range of 60° to 120°. More preferably, the relative angle between the linear portion 31a1 and the wide portion 31a2 is 90°. Furthermore, the wide portions 31a2 of adjacent orientation relaxation portions 31a are preferably formed parallel to each other, but this is not limited thereto as long as a width sufficient to form the fracture portion 3b can be ensured. The relative angle between the linear portion 31a1 and the wide portion 31a2 corresponds to, for example, the scanning direction of the laser light 210 during laser processing.

[0039] The wide portion 31a2 is formed by laser processing. Due to the characteristics of laser processing, a fixed value is selected as the set value (target value) for the width WB of the wide portion 31a2. However, variations in the measured values ​​of the processed wide portion 31a2 are permitted, and partial dimensional variations are permitted. In addition, although the wide portion 31a2 is depicted as a rectangle in FIGS. 5 and 6, due to the characteristics of laser processing, it is permitted to be formed into a circular, semicircular, or irregular shape. In this embodiment, an example is described in which the wide portion 31a2 is formed by linearly scanning the film 3 with laser light for a predetermined distance along a direction (short direction) perpendicular to the longitudinal direction of the linear portion 31a1. Hereinafter, the wide portion 31a2 may also be referred to as a second laser-processed portion.

[0040] Next, a method for manufacturing the film 3 configured as above will be described with reference to Figures 3, 5, and 6. First, the base layer 31 and the seal layer 33 are bonded together with the adhesive layer 32 to form the film 3 without the processed portion 3a. Next, the laser processing device 200 is controlled to form the processed portion 3a at a predetermined position on the film 3. Here, the laser processing device 200 includes, for example, a laser beam output unit 201 that outputs laser beam 210, and a control unit 202 that controls the laser beam output unit 201. The output, focal position, scanning direction, scanning speed, etc. of the laser beam output unit 201 are controlled by the control unit 202.

[0041] Specifically, as shown in steps ST1 and ST11, a first laser processing is performed to form a straight line portion 31a1 of the alignment relaxation portion 31a, which is disposed at one end in the arrangement direction of the alignment relaxation portions 31a, among the alignment relaxation portions 31a provided in the processing portion 3a. For example, the arrows in Figures 5 and 6 indicate the scanning direction of the laser beam 210, and the circles formed at both ends of the arrow indicate examples of the focal centers of the laser beam 210 at the start and end of the scan.

[0042] The first laser-processed portion processed by this first laser processing forms the straight line portion 31a1.

[0043] Next, as shown in steps ST2 and ST12, the second laser processing is performed by scanning the laser beam 210 in a direction perpendicular to the scanning direction of the laser beam 210 during the first laser processing, and a wide portion 31a2 is formed as a second laser-processed portion. This forms the orientation relaxation portion 31a arranged at one end in the arrangement direction.

[0044] Here, since the first laser-processed portion and the second laser-processed portion are formed in the range irradiated with the laser beam 210, the focal center of the laser beam 210 forming the first laser-processed portion and the focal center of the laser beam 210 forming the second laser-processed portion are separated by a predetermined distance, as shown in FIGS. 5 and 6 . In other words, the laser beam 210 is irradiated from the vicinity of one end of the first or second laser-processed portion that was formed first, and the other of the first or second laser-processed portion is formed. That is, if the laser beams 210 overlap excessively, there is a risk that the film 3 will melt and open, so the focal centers of the laser beams 210 are positioned apart. Note that the focal centers of the laser beams 210 may be allowed to overlap by adjusting the output power, scanning speed, etc. of the laser beam 210.

[0045] Also, for example, as in the example of Figure 5, when the wide portion 31a2 is an orientation relaxation portion 31a extending in both directions in the short direction from the straight portion 31a1, the center of focus of the laser light 210 at the starting point of the second laser processing is on an extension of the scanning direction of the first laser processing that processes the straight portion 31a1.

[0046] Furthermore, for example, as in the example of Figure 6, when the wide portion 31a2 is an orientation relaxation portion 31a extending in one direction in the short side direction from the straight portion 31a1, the focal position of the laser light 210 at the starting point of the second laser processing is a position shifted in the short side direction of the straight portion 31a1 from the extension of the scanning direction of the first laser processing that processes the straight portion 31a1.

[0047] Next, as shown in steps ST3 and ST13, the wide portion 31a2 of the alignment relaxed portion 31a adjacent to the wide portion 31a2 of the alignment relaxed portion 31a formed in steps ST2 and ST12 is formed. As a specific example, the second laser processing is performed by scanning the laser light 210 in a direction perpendicular to the scanning direction of the laser light 210 in the first laser processing, and the wide portion 31a2 is formed as the second laser processed portion. Note that, as shown in FIGS. 5 and 6, for example, the scanning direction of the laser light 210 in the second laser processing is the same as the scanning direction of the opposing wide portion 31a2.

[0048] Next, as shown in steps ST4 and ST14, a first laser processing is performed by scanning the laser beam 210 to form the straight portion 31a1. Next, as shown in steps ST5 and ST15, a second laser processing is performed by scanning the laser beam 210 to form the wide portion 31a2. As a result, the orientation relaxed portion 31a having the wide portion 31a2 at both ends is formed.

[0049] Next, as shown in steps ST6 and ST16, the wide portion 31a2 of the alignment relaxed portion 31a adjacent to the wide portion 31a2 of the alignment relaxed portion 31a formed in steps ST5 and ST15 is formed. As a specific example, the second laser processing is performed by scanning the laser beam 210 in a direction perpendicular to the scanning direction of the laser beam 210 during the first laser processing, and the wide portion 31a2 is formed as the second laser processed portion. Note that, as shown in FIGS. 5 and 6, for example, the scanning direction of the laser beam 210 during the second laser processing is the same as the scanning direction of the opposing wide portion 31a2.

[0050] Next, as shown in steps ST7 and ST17, a first laser processing is performed by scanning laser light 210 to form straight portion 31a1. This forms orientation relaxed portion 31a. Through these steps, film 3 having processed portion 3a formed therein is manufactured.

[0051] When the contents 100 of the packaging container 1 containing the contents configured in this manner are heated in a microwave oven, the pressure inside the container increases, causing the film 3 to expand into a dome shape. When the pressure inside the container reaches a predetermined internal pressure, the breaking portion 3b of the processed portion 3a formed in the film 3 breaks, releasing the pressure inside the container.

[0052] Furthermore, among the plurality of orientation relaxation portions 31a that form the processed portion 3a, at least one of the linear portions 31a1 of adjacent orientation relaxation portions 31a, preferably both of the orientation relaxation portions 31a, has a wide portion 31a2 formed at the end of the linear portion 31a1. This prevents tearing of the end of the orientation relaxation portions 31a that form the processed portion 3a of the film 3, and enables stable rupture of the rupture portion 3b.

[0053] [Evaluation test] Next, an evaluation test of the film 3 having the processed portion 3a configured as described above will be described below. For the evaluation test, three samples of each of the packaging containers 2A of Examples 1 to 7 below and the packaging container of the Comparative Example were created. The packaging containers 2A of Examples 1 to 7 below and the packaging container of the Comparative Example were formed into a bag shape by heat-sealing the four sides of two sheets of film 3.

[0054] The film 3 of the packaging containers 2A of Examples 1 to 7 and the packaging containers of the comparative examples was made of ONy(15) / / CPP(50). The processed portion 3a was formed using a carbon dioxide laser machine, LP-430U, manufactured by Panasonic Corporation.

[0055] The packaging container 2A of Example 1 had two orientation relaxation portions 31a formed as the processed portions 3a. The width WA (mm) of the straight portion 31a1 set by laser processing of the orientation relaxation portion 31a was set to 1.0 mm, and the width WB (mm) of the wide portion 31a2 (tip processing length setting) was set to 0.5 mm. Here, the tip processing length setting refers to the distance between the centers of the focal points of the laser light 210 at the scanning start and end positions when performing the second laser processing. The actual measurements of the formed orientation relaxation portion 31a were a width WA of 1.07 mm, a width WB of 1.11 mm, and a WB / WA ratio of 1.04.

[0056] The packaging container 2A of Example 2 had two orientation relaxation portions 31a, and the width WA (mm) of the straight portion 31a1 set by laser processing of the orientation relaxation portion 31a was set to 1.0 mm, and the width WB (mm) of the wide portion 31a2 (tip processing length setting) was set to 0.75 mm. The actual measured values ​​of the formed orientation relaxation portion 31a were the width WA of 1.05 mm, the width WB of 1.23 mm, and WB / WA of 1.17.

[0057] The packaging container 2A of Example 3 had two orientation relaxation portions 31a, and the width WA (mm) of the straight portion 31a1 set by laser processing of the orientation relaxation portion 31a was set to 1.0 mm, and the width WB (mm) of the wide portion 31a2 (tip processing length setting) was set to 1.0 mm. The actual measured values ​​of the formed orientation relaxation portion 31a were a width WA of 1.04 mm, a width WB of 1.34 mm, and a WB / WA ratio of 1.29.

[0058] The packaging container 2A of Example 4 had two orientation relaxation portions 31a, and the width WA (mm) of the straight portion 31a1 set by laser processing of the orientation relaxation portion 31a was set to 1.0 mm, and the width WB (mm) of the wide portion 31a2 (tip processing length setting) was set to 1.5 mm. The actual measured values ​​of the formed orientation relaxation portion 31a were the width WA of 1.06 mm, the width WB of 1.52 mm, and WB / WA of 1.43.

[0059] The packaging container 2A of Example 5 had two orientation relaxation portions 31a, and the width WA (mm) of the straight portion 31a1 set by laser processing of the orientation relaxation portion 31a was set to 1.0 mm, and the width WB (mm) of the wide portion 31a2 (tip processing length setting) was set to 2.0 mm. The actual measured values ​​of the formed orientation relaxation portion 31a were the width WA of 1.04 mm, the width WB of 1.82 mm, and WB / WA of 1.75.

[0060] The packaging container 2A of Example 6 had two orientation relaxation portions 31a, and the width WA (mm) of the straight portion 31a1 set by laser processing of the orientation relaxation portion 31a was set to 1.0 mm, and the width WB (mm) of the wide portion 31a2 (tip processing length setting) was set to 2.5 mm. The actual measured values ​​of the formed orientation relaxation portion 31a were width WA of 1.09 mm, width WB of 2.18 mm, and WB / WA of 2.00.

[0061] The packaging container 2A of Example 7 had two orientation relaxation portions 31a, and the width WA (mm) of the straight portion 31a1 set by laser processing of the orientation relaxation portion 31a was set to 1.0 mm, and the width WB (mm) of the wide portion 31a2 (tip processing length setting) was set to 3.0 mm. The actual measured values ​​of the formed orientation relaxation portion 31a were width WA of 1.07 mm, width WB of 2.59 mm, and WB / WA of 2.42.

[0062] The packaging container of the comparative example had two orientation relaxation portions 31a formed, and the width WA (mm) of the linear portion 31a1 set by laser processing of the orientation relaxation portion 31a was set to 1.0 mm, and the width WB (mm) of the wide portion 31a2 (tip processing length setting) was set to 0 mm, i.e., no wide portion 31a2 was formed. In order to set the distance between the ends of the linear portions 31a1 of adjacent orientation relaxation portions 31a to the same setting as in each example, the focal center of the scanning end position of the laser light 210 in the first laser processing was set to the same as the focal center of the laser light 210 in the second laser processing. The actual measured value of the width WA of the formed orientation relaxation portion 31a was 1.03 mm.

[0063] The widths WA and WB of the processed portions 3a in Examples 1 to 7 and the comparative example were measured on one of the three samples in each example and comparative example. The widths WA and WB of the processed portions 3a in Examples 1 to 7 and the comparative example were measured on one of the linear portions 31a1 of the two alignment relaxation portions 31a, with the width WA being the minimum width of the linear portion 31a1 and the width WB being the maximum width of the wide portion 31a2. When measuring the widths WA and WB, enlarged photographs were taken of the opposing tips of adjacent alignment relaxation portions 31a.

[0064] Then, without placing contents 100 in the packaging containers 2A of Examples 1 to 7 and the packaging container of the Comparative Example, a needle was pierced from the side opposite the processed portion 3a of the packaging container 2A using a seal tester (FKT-100J) manufactured by Sun Scientific to inject air into the packaging container 2A and cause it to expand to a certain extent. After that, the processed portion 3a side was immersed in a thermostatic water bath set at 90°C with the water surface, and the internal pressure was further increased, and the pressure (opening pressure) when one of the rupture portions 3b of the processed portion 3a broke was measured for each sample.

[0065] [Evaluation test results] The results of the evaluation test are shown in Fig. 7. Fig. 7 shows photographs of the tips of the straight portions 31a1 of the examples and comparative examples. In the photographs of the examples and comparative examples in Fig. 7, the black regions are the alignment relaxation portions 31a. In addition, in the photographs of the examples and comparative examples in Fig. 7, the areas inside the white regions (portions) around the alignment relaxation portions 31a (black regions) are the areas irradiated with the laser light 210.

[0066] As shown in FIG. 7, in one sample of the packaging container of the comparative example, the breaking portion 3b broke at 16.5 kPa. However, in two samples, the breaking portion 3b did not break, resulting in poor opening. This is because, as can be seen from the photograph, sawtooth-like irregularities may occur at the end of the straight portion 31a1. Such irregularities make the base layer 31 more likely to tear at the end of the straight portion 31a1 when the internal pressure increases. If a tear occurs in the base layer 31, only the base layer 31 breaks, and the sealing layer 33 does not break, resulting in delamination. This is thought to be why poor opening occurred in two of the three samples, as in the packaging container of the comparative example. As such, the packaging container of Comparative Example 1 resulted in poor opening stability.

[0067] In contrast, all samples of the packaging container 2 in Examples 1 to 7 broke at the breaking portion 3b. Thus, it was revealed that providing a wide portion 31a2 at the end of the straight portion 31a1 of the orientation relaxation portion 31a improved the opening stability of the processed portion 3a. The opening pressure (kPa) increased as the width WB of the wide portion 31a2 increased. This indicates that the opening pressure can be adjusted by adjusting the width WB of the wide portion 31a2. However, when the width WB of the wide portion 31a2 is greater than twice the width WA of the straight portion 31a1, as in Example 7, the opening pressure becomes too high. Therefore, it is preferable that the width WB of the wide portion 31a2 is equal to or less than twice the width WA of the straight portion 31a1, as in Examples 1 to 6, and more preferably in the range of 1.05 to 1.6 times.

[0068] The results of such evaluation tests also revealed that the opening stability of the processed portion 3a formed in the film 3 that forms part or all of the packaging container 2 can be improved by providing a wide portion 31a2 with a width WB larger than the width WA of the straight portion 31a1 at the end of adjacent orientation relaxation portions 31a.

[0069] As described above, the film 3, packaging container 2, and content-filled packaging container 1 according to the embodiment prevent tearing of the end of the processed portion 3a when the internal pressure increases, and enable the breaking portion 3b to break stably.

[0070] In the above example, a carbon dioxide laser has been described as an example of the laser light 210, but the present invention is not limited to this and may be a near-infrared laser, etc. Also, in the above example, an example has been described in which the processed portion 12a (orientation relaxation portion 31a) is formed by heating the orientation portion 31b by irradiating it with the laser light 210, but the heating method is not limited to this and methods such as hot plate heating and impulse heating in which a pressing head heated to a predetermined temperature or higher is pressed against the orientation relaxation portion 31a may also be used.

[0071] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. [Explanation of symbols]

[0072] 1...packaging container containing contents, 2, 2A...packaging container, 2a...sealed portion, 3...film, 3a...processed portion, 3b...breaking portion, 11...container body, 12...lid, 12a...processed portion, 21...body portion, 21b...orientation portion, 22...bottom, 23...flange, 31...base material layer, 31a...orientation relaxation portion, 31a1...straight portion, 31a2...wide portion (end), 31b...orientation portion, 32...adhesive layer, 33...sealing layer, 34...intermediate layer, 100...contents, 200...laser processing device, 201...laser light output unit, 202...control unit, 210...laser light

Claims

1. A film used for at least a part of a packaging container, a substrate layer; a seal layer laminated on the base material layer; a linear processed portion formed on the base material layer to form a breaking portion that breaks when an internal pressure increases; Equipped with The processed portion is formed long in one direction and has a plurality of straight portions lined up in the longitudinal direction, and the width in the short direction of at least one of the opposing ends of adjacent straight portions is larger than the smallest width in the short direction of the straight portion closer to the center than the end of the straight portion.

2. The film according to claim 1 , wherein the width of the end portion of the straight portion is within twice the minimum width of the central portion of the straight portion.

3. 3. The film according to claim 2, wherein the width of the end portion of the straight portion is 1.05 to 1.6 times the minimum width of the central portion of the straight portion.

4. A packaging container formed into a bag shape by heat-sealing one or more sheets of the film according to any one of claims 1 to 3.

5. The packaging container according to claim 4; Contents to be contained in the packaging container; A packaging container containing a content.

6. a container body having a bottom, a body, and a flange integrally formed therewith; a lid formed from the film of any one of claims 1 to 3 and heat-sealed to the flange; A packaging container comprising:

7. The packaging container according to claim 6; Contents to be contained in the packaging container; A packaging container containing a content.

8. A method for producing the film according to any one of claims 1 to 3, comprising: a laser beam is scanned in one direction on the base material layer to form a first laser-processed portion; A second laser-processed portion is formed by scanning the laser light in a direction different from the scanning direction of the laser light when the first laser-processed portion is formed in the vicinity of the end portion of the first laser-processed portion, A method for manufacturing a film, wherein one of the first laser processing section and the second laser processing section forms the straight portion, and the other of the first laser processing section and the second laser processing section forms the end of the straight portion.

9. The method for producing a film according to claim 8 , wherein a relative angle between the first laser-processed portion and the second laser-processed portion is 60° to 120°.

Images