Standing pouches and packaging articles

Abstract

To provide a standing pouch which hardly causes defects in manufacture, and hardly causes a pin hole in a film when a packaging article filled with a content article is distributed.SOLUTION: A standing pouch 110 includes a pair of body films 111A and 111B, and a bottom film 112, wherein each of the body films includes a first base material layer containing polyethylene, and a first sealant layer which is provided on the first base material layer and contains polyethylene, the bottom film includes a second base material layer containing polyethylene and a second sealant layer which is provided on the second base material layer and contains polyethylene, and degrees of crystallization of the first base material layers of the respective body films are large compared to degrees of crystallization of the second base material layer, and a difference therebetween is 15 points or more.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This invention relates to a standing pouch. [Background technology]

[0002] Packaging articles, which are filled into standing pouches, are self-supporting. Therefore, such packaging articles can be stored in a box in an upright position, for example, making packing easy. Furthermore, such packaging articles can be displayed attractively and easily on store shelves, for example. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2001-206384 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The present invention aims to provide a standing pouch that is less prone to defects during manufacturing and less prone to pinholes in the film during the distribution of packaged articles filled with contents. [Means for solving the problem]

[0005] According to one aspect of the present invention, a standing pouch is provided comprising a pair of main body films and a bottom film, wherein each of the pair of main body films comprises a first substrate layer containing polyethylene and a first sealant layer containing polyethylene provided on the first substrate layer, and the bottom film comprises a second substrate layer containing polyethylene and a second sealant layer containing polyethylene provided on the second substrate layer, and the degree of crystallinity of the first substrate layer of each of the pair of main body films is greater than that of the second substrate layer, with the difference being 15 points or more.

[0006] According to another aspect of the present invention, a standing pouch is provided comprising a pair of body films and a bottom film, wherein each of the pair of body films comprises a first substrate layer containing polyethylene and a first sealant layer containing polyethylene provided on the first substrate layer, and the bottom film comprises a second substrate layer containing polyethylene and a second sealant layer containing polyethylene provided on the second substrate layer, wherein the crystallinity of the first substrate layer of each of the pair of body films is in the range of 35% to 95%, and the crystallinity of the second substrate layer is in the range of 5% to 35%.

[0007] According to yet another aspect of the present invention, a standing pouch is provided which each of the pair of main body films further comprises a first intermediate layer containing polyethylene, interposed between the first substrate layer and the first sealant layer.

[0008] According to yet another aspect of the present invention, a standing pouch is provided which further comprises a second intermediate layer containing polyethylene, interposed between the second substrate layer and the second sealant layer, the bottom film being located within any of the above aspects.

[0009] According to yet another aspect of the present invention, a standing pouch is provided relating to any of the above aspects, wherein each of the pair of main body films further includes a first protective layer as the outermost layer facing the first sealant layer with the first substrate layer in between.

[0010] According to yet another aspect of the present invention, the first protective layer is provided as a standing pouch comprising a cured product of a thermosetting resin.

[0011] According to yet another aspect of the present invention, a standing pouch is provided which further includes a second protective layer as the outermost layer facing the second sealant layer with the second substrate layer in between, the bottom film of the present invention.

[0012] According to still another aspect of the present invention, there is provided a standing pouch according to the above aspect, wherein the second protective layer includes a cured product of a thermosetting resin.

[0013] According to still another aspect of the present invention, there is provided a standing pouch according to any of the above aspects, wherein each of the pair of body films further includes a first gas barrier layer interposed between the first base material layer and the first sealant layer.

[0014] According to still another aspect of the present invention, there is provided a standing pouch according to any of the above aspects, wherein the bottom film further includes a second gas barrier layer interposed between the second base material layer and the second sealant layer.

[0015] According to still another aspect of the present invention, there is provided a standing pouch according to any of the above aspects, wherein each of the pair of body films and the bottom film has a polyethylene content of 90% by mass or more.

[0016] According to still another aspect of the present invention, there is provided a standing pouch according to any of the above aspects for containing a content having a volume in the range of 0.2 L to 4.0 L.

[0017] According to still another aspect of the present invention, there is provided a packaged article including a standing pouch according to any of the above aspects and a content contained in the standing pouch.

[0018] According to still another aspect of the present invention, there is provided a packaged article according to the above aspect, wherein the volume of the content is in the range of 0.2 L to 4.0 L.

Advantages of the Invention

[0019] According to the present invention, there is provided a standing pouch that is less likely to cause defects during manufacturing and is less likely to cause pinholes in the film during the distribution of a packaged article filled with a content.

Brief Description of the Drawings

[0020] [Figure 1] Figure 1 is a front view of a packaged article according to an embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view showing an enlarged part of the packaged article shown in Figure 1. [Figure 3] Figure 3 is a cross-sectional view showing an enlarged part of a standing pouch used for manufacturing the packaged article of Figure 1. [Figure 4] Figure 4 is a cross-sectional view showing an example of a laminate that can be used as a body film of the standing pouch of Figure 3. [Figure 5] Figure 5 is a cross-sectional view showing an example of a laminate that can be used as a bottom film of the standing pouch of Figure 3. [Figure 6] Figure 6 is a front view of a packaged article according to a modified example.

Mode for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are more specific examples of any of the above aspects. The matters described below can be incorporated into each of the above aspects alone or in combination.

[0022] In addition, the embodiments shown below illustrate configurations for embodying the technical idea of the present invention, and the technical idea of the present invention is not limited by the materials, shapes, structures, etc. of the following constituent members. Various changes can be made to the technical idea of the present invention within the technical scope defined by the claims described in the claims.

[0023] For elements having the same or similar functions, the same reference numerals are given in the drawings referred to below, and duplicate explanations are omitted. Also, the drawings are schematic, and the relationship between dimensions in one direction and dimensions in another direction, and the relationship between the dimensions of one member and the dimensions of other members, etc. may differ from the actual ones.

[0024] <1> Standing Pouch and Packaged Article Figure 1 is a front view of a packaged article according to one embodiment of the present invention. Figure 2 is a cross-sectional view showing an enlarged portion of the packaged article shown in Figure 1. Figure 3 is a cross-sectional view showing an enlarged portion of a standing pouch used in the manufacture of the packaged article shown in Figure 1.

[0025] Here, the cross-section in Figure 2 is the portion near the bottom of the cross-section of the packaged article 100 shown in Figure 1, which is perpendicular to the width direction and passes through the center of the width. The cross-section in Figure 3 corresponds to the portion of the standing pouch 110 shown in Figure 2. Note that the standing pouch 110 has a flat shape with the bottom folded in its state immediately after manufacturing, but in Figure 3, the bottom is slightly spread out for ease of understanding.

[0026] The packaged article 100 shown in Figures 1 and 2 includes a standing pouch 110, which is the packaging body, and contents 120 contained therein.

[0027] As shown in Figures 2 and 3, the standing pouch 110 includes a pair of main body films 111A and 111B and a bottom film 112.

[0028] Each of the main body films 111A and 111B and the bottom film 112 is a laminate including a base layer and a sealant layer provided thereon, as will be described later.

[0029] In the standing pouch 110 before the contents 120 are filled, as shown in Figure 3, the main films 111A and 111B are arranged so that their sealant layers face each other. The bottom film 112 is folded in half so that it forms a mountain fold when viewed from the sealant layer side, and at one end of the main films 111A and 111B, the mountain fold portion MF is sandwiched between the main films 111A and 111B so that it faces the other end of the main films 111A and 111B.

[0030] The edges of the main films 111A and 111B are heat-sealed to each other from the position of the mountain fold MF of the bottom film 112 to the other end of the main films 111A and 111B. As a result, the main films 111A and 111B form the heat-sealed portions HS1 shown in Figure 1 on both sides.

[0031] The bottom film 112 is heat-sealed to the main film 111A and 111B in all but its central portion. Specifically, one of the two portions of the bottom film 112 separated by the mountain fold portion MF is heat-sealed to the main film 111A at a position other than the central portion of the bottom film 112, forming the heat-sealed portion HS2A shown in Figures 1 to 3. The other of the two portions of the bottom film 112 separated by the mountain fold portion MF is heat-sealed to the main film 111B at a position other than the central portion of the bottom film 112, forming the heat-sealed portion HS2B shown in Figures 2 and 3. These two portions of the bottom film 112 are then bonded together on their outer surfaces at the sides of the bottom of the standing pouch 110.

[0032] Note that the heat-sealed portions HS1 and HS4 shown in Figure 1 are portions that have been heat-sealed by the side seal and point seal, respectively, which will be described later. Also, the heat-sealed portion HS2A shown in Figures 1 to 3 and the heat-sealed portion HS2B shown in Figures 2 and 3 are portions that have been heat-sealed by the bottom seal, which will be described later.

[0033] In the packaged article 100, which contains contents 120 in a standing pouch 110, the other ends of the main films 111A and 111B are further heat-sealed. As a result, the main films 111A and 111B form a heat-sealed portion HS3 at the other end, as shown in Figure 1.

[0034] The standing pouch 110 is shaped so that its upper corner can be used as the opening after opening. An easy-opening mechanism can be provided at this corner. The easy-opening mechanism is, for example, a notch.

[0035] The standing pouch 110 may be formed so that the portion other than its upper corner can be used as a mouth after opening. For example, the standing pouch 110 may be formed so that its upper central portion can be used as a mouth after opening. The standing pouch 110 may also further include a mouth member and a lid at its upper part. For example, as in the standing pouch 110 of the packaged article 100A shown in Figure 6, a spout 113, which is a member for extracting the contents, may be interposed between the main body films 111A and 111B at the upper part of the standing pouch 110, and a cap 114, which is a member for sealing it by welding to them, may be fitted or screwed onto the mouth of the spout 113.

[0036] The contents 120 may be, for example, a liquid or a mixture of a liquid and a solid. Such contents 120 may be, for example, food or medicine.

[0037] There is no limit to the volume of the contents 120, but the technique described herein is particularly useful when the volume of the contents 120 is large. From this viewpoint, the volume of the contents 120 is preferably in the range of 0.2 to 4.0 L. More preferably, the volume of the contents 120 is 0.8 L or more. Furthermore, it is even more preferable that the volume of the contents 120 is 3.0 L or less.

[0038] <2> Body film Figure 4 is a cross-sectional view showing an example of a laminate that can be used as the main film of the standing pouch shown in Figure 3.

[0039] The laminate 10 shown in Figure 4 can be used for the main films 111A and 111B. As will be described later, the laminate 10 can be modified in various ways. Laminates relating to these modified forms can also be used for the main films 111A and 111B.

[0040] The laminate 10 includes, in this order, a protective layer 16, a substrate layer 11, a printing layer 14, an adhesive layer 13A, an intermediate layer 18, an inorganic compound layer 15, a coating layer 17, an adhesive layer 13B, and a sealant layer 12.

[0041] As described later, the base layer 11, the intermediate layer 18, and the sealant layer 12 contain polyethylene. Preferably, the polyethylene content of the laminate 10 is 90% by mass or more. Here, the polyethylene content in the laminate refers to the ratio of the total amount of polyethylene to the total amount of resin material in each layer constituting the laminate. By setting the polyethylene content to 90% by mass or more, high recyclability can be achieved.

[0042] <2.1> Base material layer The base layer 11 is a first base layer. The base layer 11 contains polyethylene. Preferably, the base layer 11 is made of polyethylene.

[0043] The crystallinity of the base layer 11 is greater than that of the base layer 21, which will be described later, for the bottom film 112. The difference in crystallinity is 15 points or more, preferably 20 points or more. The difference in crystallinity is, for example, 70 points or less. The base layer 11 is required to have puncture resistance. If the crystallinity of the base layer 21 is made close to that of the base layer 11 while simultaneously selecting a crystallinity that satisfies this requirement, the film will curl too much when attempting to manufacture a standing pouch, making it impossible to manufacture a pouch. Therefore, it is preferable that the crystallinity of the base layer 21 is somewhat lower than that of the base layer 11. Specifically, it is preferable that it is 15 points or more lower.

[0044] The crystallinity of the base layer 11 is preferably in the range of 35% to 95%. More preferably, the crystallinity of the base layer 11 is 40% or more, and even more preferably 50% or more. Furthermore, the crystallinity of the base layer 11 is preferably 90% or less.

[0045] Here, "crystallinity" is the ratio of the crystal peak area to the total peak area, measured by the parallel beam method of X-ray diffraction in the diffraction angle range of 10° to 30°. The method for measuring crystallinity will be described in detail later.

[0046] As will be described later, a standing pouch 110 employing this configuration is less prone to defects during manufacturing. Furthermore, as will be described later, a packaged article 100 formed by filling a standing pouch 110 employing this configuration with contents 120 is less prone to developing pinholes in the film during distribution.

[0047] The polyethylene contained in the base layer 11 may be an ethylene homopolymer or a copolymer of ethylene and other monomers. When the polyethylene is a copolymer of ethylene and other monomers, the proportion of ethylene in the copolymer is, for example, 80 mol% or more.

[0048] Other monomers include, for example, α-olefins. For example, α-olefins have a carbon number in the range of 3 to 20. Such α-olefins include, for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, or 6-methyl-1-heptene.

[0049] Polyethylene may be a copolymer of ethylene and one of vinyl acetate or acrylic acid ester. Alternatively, it may be a copolymer of ethylene and vinyl acetate, its fully or partially saponified form, (meth)acrylic acid, or its esterified or ionic crosslinked product.

[0050] The base layer 11 is, for example, high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or very low-density polyethylene (VLDPE).

[0051] Here, high-density polyethylene has a density of 0.942 g / cm³. 3 In summary, medium-density polyethylene has a density of 0.930 g / cm³. 3 More than 0.942g / cm 3 It is less than 0.910 g / cm³, and low-density polyethylene has a density of 0.910 g / cm³. 3 More than 0.930g / cm 3 The density of linear low-density polyethylene is less than 0.910 g / cm³. 3 The above is 0.930cm 3 Ultra-low density polyethylene has a density of less than 0.910 g / cm³. 3 It is less than. The density is a value obtained using a method compliant with JIS K7112:1999.

[0052] The polyethylene contained in the base layer 11 may be biomass-derived polyethylene. For example, green polyethylene (manufactured by Braskem) can be used as biomass-derived polyethylene.

[0053] Alternatively, the polyethylene contained in the base layer 11 may be polyethylene recycled by mechanical recycling. Here, mechanical recycling refers to the decontamination of polyethylene film by crushing the collected polyethylene film, then washing the crushed film with alkali to remove dirt and foreign matter from the film surface, and finally drying it at high temperature and reduced pressure to diffuse any contaminants remaining inside the film.

[0054] Alternatively, the polyethylene contained in the base layer 11 may be polyethylene recycled through chemical recycling. The melting point of the base layer 11 is preferably in the range of 100°C to 140°C, and more preferably in the range of 120°C to 140°C. The melting point is a value obtained by a method in accordance with JIS K7121-1987.

[0055] The base layer 11 may be an unoriented film or an oriented film. It is preferable that the base layer 11 be an oriented film. If the base layer 11 is an oriented film, it may be a uniaxially oriented film or a biaxially oriented film. When the base layer 11 is an oriented film with a crystallinity of 35% or more, the following effects are obtained: Specifically, it exhibits particularly excellent heat resistance and strength. Furthermore, the elongation of the base layer 11 is reduced, improving printability. In this specification, the term "film" does not include the concept of thickness.

[0056] Whether a stretched film is uniaxially oriented or biaxially oriented can be determined by performing an in-plane measurement using wide-angle X-ray diffraction, as described below. The X-ray diffraction pattern obtained from this measurement contains information about the degree of orientation of molecular chains present on the film surface.

[0057] When a polymer film is uniaxially stretched, a higher-order structure called a shish-kebab structure appears. The shish-kebab structure consists of shish structures, which are elongated chain crystals, and kebab structures, which are lamellar crystals. In uniaxially stretched films, these higher-order structures are arranged with a high degree of order, and therefore, the X-ray diffraction pattern obtained by the above measurement on a uniaxially stretched film will contain sharp diffraction peaks. In other words, when the above measurement is performed on a uniaxially stretched film, clear diffraction peaks appear. Note that "clear diffraction peaks" refers to diffraction peaks with a full width at half maximum of less than 10°.

[0058] In contrast, in the manufacture of biaxially oriented films, the film is stretched in a specific direction, and then in a direction perpendicular to the first stretch. Therefore, although the above-mentioned higher-order structure is produced by the first stretch, this higher-order structure is disturbed by the second stretch. Consequently, when the above measurements are performed on a biaxially oriented film, the resulting X-ray diffraction pattern shows broad diffraction peaks. In other words, when the above measurements are performed on a biaxially oriented film, no clear diffraction peaks appear.

[0059] As described above, the X-ray diffraction patterns obtained by the above measurements differ between uniaxially oriented films and biaxially oriented films. Therefore, based on this, it is possible to determine whether a stretched film is uniaxially oriented or biaxially oriented.

[0060] The film can be manufactured by known methods such as the casting method and the inflation method. Alternatively, a multilayer polyethylene film obtained by co-extruding polyethylenes of different densities can be used as the base layer 11. The stretched film can be obtained, for example, by stretching a film obtained by forming a polyethylene film using the T-die method or the inflation method.

[0061] The haze of the base layer 11 is preferably 20% or less, and more preferably 10% or less. The haze value is obtained by a method in accordance with JIS K7136:2000.

[0062] The thickness of the base layer 11 is preferably in the range of 10 μm to 200 μm. For example, the thickness of the base layer 11 may be in the range of 10 μm to 50 μm, or in the range of 15 μm to 50 μm, or in the range of 12 μm to 35 μm. If the base layer 11 is too thin, the strength of the laminate 10 tends to be low. Also, if the base layer 11 is too thick, the processability of the laminate 10 tends to decrease.

[0063] The base layer 11 is preferably surface-treated. This treatment improves the adhesion between the base layer 11 and the layer adjacent to it.

[0064] The surface treatment method is not particularly limited. Examples of surface treatments include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, glow discharge treatment, and chemical treatments such as oxidation treatment using chemicals.

[0065] The base layer 11 may further contain additives. Examples of additives include crosslinking agents, antioxidants, antiblocking agents, lubricants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0066] The proportion of polyethylene in the base layer 11 is preferably 50% by mass or more, and more preferably 80% by mass or more. In one example, the base layer 11 is made of polyethylene. In another example, the base layer 11 is made of polyethylene and an additive.

[0067] The base layer 11 may be colored, for example, it may be white.

[0068] As described above, the base layer 11 has a higher degree of crystallinity compared to the base layer 21. Such a base layer 11 does not hinder the visibility of images such as patterns and characters displayed by the printed layer 14, enabling the image to be viewed with good visibility. Furthermore, the laminate 10 containing such a base layer 11 also has excellent puncture strength, as will be explained below. From these viewpoints, it is preferable that the degree of crystallinity of the base layer 11 is within the range described above.

[0069] Polyethylene is a crystalline polymer, and therefore contains both crystalline and amorphous regions. Polyethylene with a high degree of crystallinity has a high proportion of crystalline regions. Since these crystalline regions govern the elastic portion of the resin's viscoelastic behavior, a higher degree of crystallinity improves the rigidity of the film.

[0070] Due to this viscoelastic behavior, in films with a high degree of crystallinity, the strain associated with the plastic deformation of the resin is also greater. As a result, the deformation of the resin is suppressed in response to the strain generated by an instantaneous impact applied to the film, making fracture less likely. Therefore, a laminate 10 having a base layer 11 containing polyethylene and with a high degree of crystallinity can have high puncture strength.

[0071] As the polyethylene constituting this base layer 11, an ethylene-α-olefin copolymer obtained by copolymerizing α-olefin is preferably used. This is because when the degree of crystallinity of the main base layer 21 is adjusted to 35% or higher, tie molecules are more easily formed between the crystals. Not only is rigidity improved by the increased degree of crystallinity, but toughness is also expected to be improved by the formation of tie molecules. When such a base layer 11 is used in the main film, a standing pouch with particularly excellent puncture resistance can be realized. In this case, the ethylene-α-olefin copolymer in the base layer 11 may be used alone or in a mixture with other polyethylenes.

[0072] The degree of crystallinity of the base layer 11 can be adjusted by controlling the degree of stretching of the polyethylene film used for the base layer 11, or by controlling the thermal history during or after film manufacturing. For example, slow cooling after film formation increases the degree of crystallinity, while rapid cooling decreases it. It is also possible to improve the degree of crystallinity by incorporating additives such as crystal nucleating agents.

[0073] <Method for measuring crystallinity> The crystallinity of the substrate layer 11 is measured by X-ray diffraction using the parallel beam method. An example of the crystallinity measurement method is described below.

[0074] First, the X-ray diffraction pattern of the substrate layer 11 is obtained by out-of-plane measurement using a wide-angle X-ray diffractometer manufactured by Rigaku Corporation, scanning the diffraction angle range of 10° to 30° in a 2θ / θ range. Characteristic X-ray CuKα is used as the X-ray, and the X-ray is parallelized by a multilayer mirror before being incident on the substrate layer 11. A scintillation detector with a flat plate collimator is used as the light receiving unit.

[0075] From the obtained X-ray diffraction pattern, the peak area of ​​the crystalline component and the halo pattern area of ​​the amorphous component are determined, and the ratio of the peak area of ​​the crystalline component to the sum of these areas is calculated as the degree of crystallinity. If the substrate layer 11 has multiple layers, the degree of crystallinity of one of the outermost surfaces of the substrate layer 11 is measured.

[0076] When the substrate layer 11 is a polyethylene film, scanning in the diffraction angle range of 10° to 30° reveals two sharp crystalline component peaks corresponding to the (110) and (200) planes, and a broad amorphous component halo pattern. By separating and analyzing these, and calculating the area of ​​the crystalline component peak and the area of ​​the amorphous component halo pattern, the degree of crystallinity can be determined from the following equation (1).

[0077] Crystallinity = Peak area of ​​crystalline component / (Peak area of ​​crystalline component + Halo pattern area of ​​amorphous component) ... (1) While the focusing method is known as an X-ray diffraction method other than the parallel beam method, with the focusing method, when the sample has surface irregularities such as those of a resin film, the measurement results are easily affected by the positional displacement of the measurement surface, such as peak broadening. In contrast, with the parallel beam method, even when the sample has surface irregularities, the positional displacement of the measurement surface has little effect on the measurement results.

[0078] On the other hand, the base layer 11 is preferably a uniaxially oriented film or a biaxially oriented film, but as described above, an in-plane method using X-ray diffraction can be used to distinguish between them. In this in-plane method, the X-ray incidence angle θ and the angle 2θ at which the diffracted X-rays are detected by the detector are fixed to the angles θ and 2θ at which diffraction peaks corresponding to a specific crystal plane are detected in the out-of-plane method described above, for example, the diffraction peak corresponding to the (110) plane of a polyethylene film, and in this state, a diffraction pattern is obtained by scanning the film to be measured in the in-plane direction.

[0079] When in-plane measurement is performed on a uniaxially oriented film stretched uniaxially in the mechanical direction (MD), if the MD direction is defined as 0°, a diffraction pattern can be obtained in which sharp diffraction peaks corresponding to the (110) plane are located at angles 2θ of approximately ±90°. On the other hand, in the case of a biaxially oriented film, the higher-order structure obtained by uniaxial stretching is disturbed by the second stretching, and the anisotropy is reduced, so a diffraction pattern with sharp diffraction peaks corresponding to the (110) plane cannot be obtained. Therefore, in-plane measurement can be cited as one method for distinguishing between uniaxially oriented films and biaxially oriented films.

[0080] <2.2>Sealant layer The sealant layer 12 is the first sealant layer. The sealant layer 12 faces the base layer 11. The sealant layer 12 contains polyethylene. Preferably, the sealant layer 12 is made of polyethylene. As the polyethylene, for example, the polyethylene described above for the polyethylene contained in the base layer 11 can be used. The sealant layer 12 is preferably low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or very low-density polyethylene (VLDPE), and more preferably linear low-density polyethylene.

[0081] From an environmental perspective, it is preferable that the polyethylene used is biomass-derived polyethylene or recycled polyethylene.

[0082] The sealant layer 12 may further contain the additives described above. The proportion of polyethylene in the sealant layer 12 is preferably 50% by mass or more, and more preferably 80% by mass or more. In one example, the sealant layer 12 is made of polyethylene. In another example, the sealant layer 12 is made of polyethylene and additives.

[0083] The sealant layer 12 may be transparent or opaque. In the latter case, the sealant layer 12 may be white, black, gray, or sepia. In the sealant layer 12, these opaque layers may be used alone, or they may form a multilayer structure containing two or more of them, or they may be combined with a transparent sealant. When the laminate 10 in which the sealant layer 12 is transparent is used as the main film 111A and 111B of the standing pouch 110, the contents 120 are easily visible. When the laminate 10 in which the sealant layer 12 is opaque is used as the main film 111A and 111B of the standing pouch 110, the contents 120 do not obstruct the visibility of the image displayed by the printing layer 14. In particular, a white sealant layer 12 improves the visibility of the image displayed by the printing layer 14.

[0084] The sealant layer can be colored white, gray, or black by mixing pigments or other substances into its resin material. For example, mixing titanium dioxide into the resin material of the sealant layer results in a white layer, mixing carbon black results in a black layer, and mixing both results in a gray layer. When light-shielding properties are required for the sealant layer, it is preferable that it be black, gray, or sepia in color. Light-shielding sealants, for example, contain carbon black.

[0085] The thickness of the sealant layer 12 can be appropriately set considering the shape of the packaging bag to be manufactured and the mass of the contents to be contained, but for example, 30 μm or more is preferred, and 60 μm or more is more preferred from the viewpoint of content retention. Furthermore, from the viewpoint of bag manufacturing efficiency and cost, it is preferably 300 μm or less, and more preferably 200 μm or less.

[0086] The sealant layer 12 is, for example, an unstretched polyethylene resin film or a layer formed by melt extrusion of polyethylene.

[0087] <2.3>Printing layer The printed layer 14 is the first printed layer. The printed layer 14 is provided on the surface of the substrate layer 11 facing the sealant layer 12, that is, on the back surface of the substrate layer 11. The position where the printed layer 14 is provided is not limited. That is, the printed layer 14 may be provided on the surface of the substrate layer 11, or at any position between the substrate layer 11 and the sealant layer 12. For example, the printed layer 14 may be provided on any surface of the intermediate layer 18. Also, the laminate 10 may contain multiple printed layers. The printed layer 14 may be omitted.

[0088] The printing ink used for the printing layer 14 is not particularly limited as long as it has adhesion to polyethylene. The printing layer 14 is composed of an ink in which various pigments, extender pigments, plasticizers, drying agents, and stabilizers are added to a conventionally used ink binder resin such as urethane, acrylic, nitrocellulose, rubber, and vinyl chloride. It is preferable to use biomass-derived ink as the printing ink. As for the printing method, well-known printing methods such as offset printing, gravure printing, flexographic printing, and silkscreen printing, as well as well-known coating methods such as roll coating, knife-edge coating, and gravure coating can be used. Light-shielding inks can also be preferably used. Examples of light-shielding inks include white ink, black ink, silver ink, and sepia ink.

[0089] <2.4> Middle Class The intermediate layer 18 is the first intermediate layer. The intermediate layer 18 is provided between the base layer 11 and the sealant layer 12. Here, the intermediate layer 18 is provided between the base layer 11 and the sealant layer 12 such that the printing layer 14 is interposed between the base layer 11 and the intermediate layer 18. The intermediate layer 18 can be omitted.

[0090] The intermediate layer 18 contains polyethylene. As the polyethylene, for example, the polyethylene described above for the polyethylene contained in the base layer 11 can be used.

[0091] The polyethylene contained in the intermediate layer 18 may be the same as or different from the polyethylene contained in the base layer 11. Furthermore, the intermediate layer 18 may also contain the additives mentioned above.

[0092] The proportion of polyethylene in the intermediate layer 18 is preferably 50% by mass or more, and more preferably 80% by mass or more. In one example, the intermediate layer 18 is made of polyethylene. In another example, the intermediate layer 18 is made of polyethylene and an additive.

[0093] For example, the intermediate layer 18 has a crystallinity of less than 35%. By using a film with a low crystallinity as the intermediate layer 18, the strength of the laminate 10 can be improved, and in particular, damage (breakage) due to dropping the packaged article 100 can be made less likely. From this viewpoint, it is preferable that the intermediate layer 18 is an unstretched film.

[0094] In other examples, the intermediate layer 18 preferably has a crystallinity of 35% or more, more preferably 40% or more, and even more preferably 50% or more. In one example, the crystallinity of the intermediate layer 18 is 75% or less.

[0095] Using a film with a high degree of crystallinity as the intermediate layer 18 increases the strength of the laminate 10, particularly its puncture strength. Laminates with a high proportion of polyethylene are less rigid compared to other laminates, and therefore are more likely to be bent when used as packaging material. Increased bending increases the likelihood of pinhole formation, but laminates 10 with excellent puncture strength are less prone to pinhole formation. From this viewpoint, the intermediate layer 18 is preferably a stretched film, and it is more preferable that both the base layer 11 and the intermediate layer 18 are stretched films. In this case, the stretched film constituting the intermediate layer 18 may be the same as or different from the stretched film constituting the base layer 11.

[0096] The melting point of the intermediate layer 18 is preferably in the range of 100°C to 140°C, and more preferably in the range of 120°C to 140°C.

[0097] The thickness of the intermediate layer 18 is preferably in the range of 10 μm to 200 μm, and more preferably in the range of 15 μm to 50 μm.

[0098] The intermediate layer 18 may be colored, for example, it may be white.

[0099] The intermediate layer 18 can be manufactured by known methods such as the casting method or the inflation method. Alternatively, a multilayer polyethylene film obtained by co-extruding polyethylenes of different densities can be used as the intermediate layer 18. The stretched film can be obtained, for example, by stretching a film obtained by forming a polyethylene film using the T-die method or the inflation method.

[0100] <2.5>Inorganic compound layer The inorganic compound layer 15 is the first inorganic compound layer. The inorganic compound layer 15 is provided on one side of the intermediate layer 18. Here, the inorganic compound layer 15 is provided on the side of the intermediate layer 18 facing the sealant layer 12. The inorganic compound layer 15 may also be provided on the side of the intermediate layer 18 facing the substrate layer 11. The inorganic compound layer 15 may be provided on the side of the substrate layer 11 facing the sealant layer 12, here between the substrate layer 11 and the printing layer 14. The inorganic compound layer 15 may be provided on the side of the substrate layer 11 opposite to the sealant layer 12, here as the outermost layer of the laminate. The inorganic compound layer 15 can be omitted.

[0101] The inorganic compound layer 15 is a thin film made of an inorganic compound, such as an inorganic oxide like aluminum oxide or silicon oxide, and functions as a gas barrier layer or part thereof that suppresses the permeation of oxygen and water vapor. The inorganic compound layer 15 may be formed by coating or by depositing an inorganic compound.

[0102] Examples of inorganic compounds included in the inorganic compound layer 15 include metal oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. The inorganic compound layer 15 is preferably a vapor-deposited film made of a metal oxide. From the viewpoint of transparency and barrier properties, the metal oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Considering cost, it is preferable that the metal oxide be selected from aluminum oxide and silicon oxide. From the viewpoint of excellent tensile stretchability during processing, it is preferable to use silicon oxide as the metal oxide. By making the inorganic compound layer 15 a vapor-deposited film made of a metal oxide, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the laminate 10.

[0103] Because metal oxide vapor-deposited films are transparent, they have the advantage of being less likely to cause users to mistakenly believe that metal foil is used when handling laminated packaging materials, compared to vapor-deposited films made of metal.

[0104] The thickness of the vapor-deposited aluminum oxide film is preferably between 5 nm and 30 nm. A thickness of 5 nm or more provides sufficient gas barrier properties. A thickness of 30 nm or less suppresses crack formation due to deformation caused by internal stress in the thin film, thereby suppressing a decrease in gas barrier properties. However, a thickness exceeding 30 nm is undesirable from an economic standpoint because it tends to increase costs due to increased material usage and longer film formation times. From the same viewpoint as above, a thickness of 7 nm or more and 15 nm is more preferable for the vapor-deposited aluminum oxide film.

[0105] The thickness of the silicon dioxide vapor-deposited film is preferably between 10 nm and 50 nm. A thickness of 10 nm or more provides sufficient gas barrier properties. A thickness of 50 nm or less suppresses crack formation due to deformation caused by internal stress in the thin film, thereby suppressing a decrease in gas barrier properties. However, a thickness exceeding 50 nm is undesirable from an economic standpoint because it tends to increase costs due to increased material usage and longer film formation times. From the same viewpoint as above, a thickness of 20 nm or more and 40 nm is more preferable for the silicon dioxide vapor-deposited film.

[0106] The inorganic compound layer 15 can be formed, for example, by vacuum deposition. For vacuum deposition, physical vapor deposition or chemical vapor deposition can be used. Examples of physical vapor deposition include vacuum deposition, sputtering, and ion plating, but are not limited to these. Examples of chemical vapor deposition include thermal CVD (Chemical Vapor Deposition), plasma CVD, and photoCVD, but are not limited to these.

[0107] In the vacuum deposition methods described above, resistance heating vacuum deposition, EB (Electron Beam) heating vacuum deposition, induction heating vacuum deposition, sputtering, reactive sputtering, dual magnetron sputtering, and plasma chemical vapor deposition (PECVD) are particularly preferred. Considering productivity, vacuum deposition is currently the most superior method. As a heating means for vacuum deposition, it is preferable to use one of the following methods: electron beam heating, resistance heating, or induction heating.

[0108] Metal vapor-deposited films, such as aluminum, are suitable for disposal. If the required light-shielding and barrier performance are met, an aluminum vapor-deposited film can be used instead of the inorganic compound layer 15. The thickness of the aluminum vapor-deposited layer is preferably 40 nm to 80 nm. The aluminum vapor-deposited layer can be provided in the intermediate layer 18, the substrate layer 11, or the sealant layer 12. When the aluminum vapor-deposited layer is provided in the sealant layer 12, it is preferably about 40 nm thick, and when it is provided in the intermediate layer 18 or the substrate layer 11, it is preferably about 80 nm thick.

[0109] <2.6> Covering layer The coating layer 17 is the first coating layer. The coating layer 17 coats the inorganic compound layer 15. The laminate of the inorganic compound layer 15 and the coating layer 17 constitutes a first gas barrier layer that improves the oxygen barrier and water vapor barrier properties of the laminate 10. The first gas barrier layer may contain only the inorganic compound layer 15, or only the coating layer 17. The laminate 10 may not contain the first gas barrier layer.

[0110] The coating layer 17 can be formed, for example, by coating. For this coating, a coating solution containing resins such as polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, polyvinylidene chloride, polyacrylonitrile, and epoxy resin can be used. Additives such as organic or inorganic particles, layered compounds, and curing agents may be added to this coating solution.

[0111] The coating layer 17 may be an organic-inorganic composite layer comprising, for example, a metal alkoxide, a hydrolysate of a metal alkoxide, and at least one of the reaction products of a metal alkoxide or a hydrolysate of a metal alkoxide, and a water-soluble polymer. This organic-inorganic composite layer may further comprise at least one of a silane coupling agent, a hydrolysate of a silane coupling agent, and the reaction product of a silane coupling agent or a hydrolysate of a silane coupling agent.

[0112] Examples of metal alkoxides and their hydrolyzates include those represented by the general formula M(OR) such as tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3], n and their hydrolyzates. One of these may be used alone or two or more of them may be used in combination.

[0113] In the coating liquid used for forming the organic-inorganic composite layer, the total content of the metal alkoxide, its hydrolyzate or their reaction product may be, for example, 40% by mass or more, 50% by mass or more, or 65% by mass or more from the viewpoint of oxygen barrier property. Also, the total content of the metal alkoxide, its hydrolyzate or their reaction product in the coating liquid may be, for example, 70% by mass or less.

[0114] The water-soluble polymer contained in the organic-inorganic composite layer is not particularly limited, and examples thereof include polyvinyl alcohol-based, polysaccharides such as starch, methylcellulose, carboxymethylcellulose, and hydroxyl group-containing polymers such as acrylic polyol-based. From the viewpoint of further improving the oxygen gas barrier property, it is preferable that the water-soluble polymer contains a polyvinyl alcohol-based water-soluble polymer. The number average molecular weight of the water-soluble polymer is, for example, in the range of 40,000 to 180,000.

[0115] The polyvinyl alcohol-based water-soluble polymer contained in the organic-inorganic composite layer can be obtained, for example, by saponifying (including partial saponification) polyvinyl acetate. This water-soluble polymer may have several tens of % of acetate groups remaining or may have only a few % of acetate groups remaining.

[0116] In the coating liquid used for forming the organic-inorganic composite layer, the content of the water-soluble polymer may be, for example, 15% by mass or more, 20% by mass or more from the viewpoint of oxygen barrier property. Also, the content rate of the water-soluble polymer in the coating liquid may be, for example, 50% by mass or less, 45% by mass or less from the viewpoint of oxygen barrier property.

[0117] Examples of silane coupling agents used in organic-inorganic composite layers include silane coupling agents having organic functional groups. Such silane coupling agents include ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidooxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane. A silane coupling agent selected from these, its hydrolysate, and their reaction products can be used individually or in combination of two or more.

[0118] It is preferable to use a silane coupling agent that has an epoxy group as an organic functional group. Examples of silane coupling agents having an epoxy group include γ-glycidooxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Silane coupling agents having an epoxy group may also have organic functional groups other than the epoxy group, such as vinyl groups, amino groups, methacrylic groups or ureyl groups, or isocyanate groups. Furthermore, these may be derivatized, polyfunctionalized, or compounded. One of the silane coupling agents selected from these, their hydrolysates, and their reaction products can be used individually or in combination of two or more.

[0119] Silane coupling agents having organic functional groups, their hydrolysates, or their reaction products can further improve the oxygen barrier properties of the coating layer 17 and the adhesion to adjacent layers through the interaction of their organic functional groups with the hydroxyl groups of water-soluble polymers. In particular, when the silane coupling agent, its hydrolysate, or their reaction products have epoxy groups and the water-soluble polymer is polyvinyl alcohol (PVA), the interaction of the epoxy groups with the hydroxyl groups of PVA can further improve the oxygen barrier properties and the adhesion to adjacent layers.

[0120] The total content of the silane coupling agent, its hydrolysate, and their reaction products in the coating solution used to form the organic-inorganic composite layer may be 1% by mass or more, or 2% by mass or more, from the viewpoint of oxygen barrier properties. Furthermore, the total content of the silane coupling agent, its hydrolysate, and their reaction products in the above coating solution may be 15% by mass or less, or 12% by mass or less, from the viewpoint of oxygen barrier properties.

[0121] The thickness of the coating layer 17 is preferably 50 nm or more and 1000 nm or less, and more preferably 100 nm or more and 500 nm or less. When the thickness of the coating layer 17 is 50 nm or more, high gas barrier properties tend to be obtained, and when it is 1000 nm or less, sufficient flexibility tends to be maintained.

[0122] <2.7>Adhesive layer Adhesive layer 13A bonds the substrate layer 11, on which the printed layer 14 is provided, to the intermediate layer 18. Adhesive layer 13B bonds the intermediate layer 18, on which the inorganic compound layer 15 and the coating layer 17 are provided, to the sealant layer 12. If the intermediate layer 18 is omitted, one of the adhesive layers 13A or 13B can be omitted.

[0123] The adhesive layers 13A and 13B consist of at least one type of adhesive. The adhesive may be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. The adhesive may be a solvent-free adhesive or a solvent-based adhesive.

[0124] Examples of adhesives include polyether-based adhesives, polyester-based adhesives, silicone-based adhesives, epoxy-based adhesives such as polyamine-based adhesives, urethane-based adhesives, rubber-based adhesives, vinyl-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and olefin-based adhesives. Adhesives containing biomass components can also be preferably used. Preferably, the adhesive is a polyamine-based adhesive or a urethane-based adhesive having gas barrier properties. Specific examples of gas barrier adhesives include "Maxieve" manufactured by Mitsubishi Gas Chemical Company and "Paslim" manufactured by DIC Corporation.

[0125] The adhesive layers 13A and 13B may be cured products of a resin composition containing a polyester polyol and an isocyanate compound, and may also be cured products of a resin composition further containing a phosphate-modified compound if necessary. Among the resin compositions used for such adhesive layers 13A and 13B, taking as an example a polyol as the main component and an isocyanate compound as the curing agent, or a polyamine resin as the main component and an epoxy compound as the curing agent, it is preferable that either or both of the main component and the curing agent have a bent structure as well as a linear structure, or contain units capable of forming such a structure. For example, by incorporating compounds having substituents at the ortho or meta position of an aromatic ring into these structures, it becomes possible to form not only linear crosslinks but also bent crosslink structures in the cured film. This bent crosslink structure controls the orientation of molecules, thereby contributing to oxygen barrier properties and water vapor barrier properties. If necessary, inorganic compounds such as inorganic layered compounds may be added to the resin composition to further improve barrier properties. This further improves the oxygen barrier and water vapor barrier properties of the laminate 10.

[0126] The thickness of each of the adhesive layers 13A and 13B is preferably in the range of 0.1 μm to 20 μm, more preferably in the range of 0.5 μm to 10 μm, and even more preferably in the range of 1 to 5 μm.

[0127] The adhesive layers 13A and 13B can be formed by applying and drying them on the intermediate layer 18 and the sealant layer 12 using conventionally known methods such as the direct gravure roll coating method, gravure roll coating method, kiss coating method, reverse roll coating method, fontein method, and transfer roll coating method.

[0128] <2.8>Protective layer The protective layer 16 is the first protective layer. The protective layer 16 is the outermost layer of the laminate 10 and covers the back surface of the surface of the base layer 11 facing the sealant layer 12. The protective layer 16 may be omitted.

[0129] The protective layer 16 contains a cured product of a thermosetting resin. The thermosetting resin is not particularly limited as long as it produces a heat-resistant cured product, and examples include polyurethane resin, polyester resin, polyamide resin, polyamide-imide resin, acrylic resin, epoxy resin, and water-soluble polymers. The protective layer 16 may contain one type of cured product of the thermosetting resin, or it may contain two or more types. Inorganic fillers may be added to the protective layer 16, for example, to improve heat resistance.

[0130] In one embodiment, the protective layer 16 preferably contains a water-soluble polymer, and more preferably is an organic-inorganic composite layer further containing an organometallic compound.

[0131] Examples of water-soluble polymers include polyvinyl alcohol-based polymers, polysaccharides such as starch, methylcellulose, and carboxymethylcellulose, and hydroxyl group-containing polymers such as acrylic polyol-based polymers. In one embodiment, the protective layer 16 preferably contains a polyvinyl alcohol-based hydroxyl group-containing polymer that can be contained in the coating layer 17.

[0132] The protective layer 16 preferably contains, as an organometallic compound, at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, and a reaction product of a metal alkoxide or a hydrolysate of a metal alkoxide. Examples of metal alkoxides include tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3], which have the general formula M(OR). n Examples include those represented by the following:

[0133] Furthermore, it is preferable that the protective layer 16 further contains, as an organometallic compound, at least one of a silane coupling agent, a hydrolysate of a silane coupling agent, and a reaction product of a silane coupling agent or a hydrolysate of a silane coupling agent.

[0134] In one embodiment, the protective layer 16 can be formed using a coating solution for forming the coating layer 17. If the laminate 10 includes the coating layer 17, the protective layer 16 may be a layer formed using the same coating solution as the coating layer 17. The protective layer 16 is not limited to the method using the coating solution described above; it can also be formed by co-extrusion of the polyethylene resin constituting the base layer 11 or base layer 21 with a thermoplastic resin that has a high melting point and heat resistance. In this case, as the thermoplastic resin that has a high melting point, resins such as polyester resin, polyamide resin, polypropylene resin, and polymethylpentene resin can be used. At this time, considering the adhesion between the polyethylene resin constituting the base layer 11 or base layer 21 and the thermoplastic resin that has a high melting point and heat resistance, an adhesive resin can also be interposed between them.

[0135] The protective layer 16 reduces thermal damage to the surface of the laminate 10 during heat sealing. By providing the laminate 10 with a heat-resistant protective layer 16 as its outermost layer, heat sealability and productivity are ensured even when using polyethylene resin, which has poor heat resistance, as the base material.

[0136] The thickness of the protective layer 16 is preferably in the range of 0.3 μm to 3 μm. If the protective layer 16 is too thin, it tends to be difficult to achieve high heat resistance. If the protective layer 16 is too thick, it tends to be difficult to sufficiently dry the resin cured film during the manufacturing process of the laminate 10.

[0137] Furthermore, the protective layer 16 is expected to not only suppress the occurrence of defects during bag making by providing heat resistance to the base layer 11, but also to suppress pinholes during transportation.

[0138] <2.9> Other layers The laminate 10 may further include one or more other layers. For example, the laminate 10 may further include an anchor coat layer covering the surface on which the inorganic compound layer 15 of the intermediate layer 18 is formed. Alternatively, the laminate 10 may further include an anchor coat layer covering the surface of the base layer 11 facing the adhesive layer 13A. Alternatively, the laminate 10 may further include an anchor coat layer covering the surface on which the inorganic compound layer 15 of the intermediate layer 18 is formed, and an anchor coat layer covering the surface of the base layer 11 facing the adhesive layer 13A.

[0139] The anchor coat layer can be formed using a known anchor coat agent. This improves the adhesion between layers, for example, the adhesion between the intermediate layer 18 and the inorganic compound layer 15 made of a metal oxide. Examples of anchor coat agents include polyester polyurethane resins and polyether polyurethane resins. Alternatively, the anchor coat layer can be a polyurethane-based cured film obtained by reacting an isocyanate compound with various hydroxyl group-containing polymers such as polyester polyols, polyether polyols, and acrylic polyols. Furthermore, to improve the adhesion between the substrate and the vapor-deposited layer, the anchor coat agent can be blended with the various silane coupling agents mentioned above. From the viewpoint of heat resistance and interlayer adhesion strength, a polyester polyurethane resin is preferred as the anchor coat agent.

[0140] <3> Bottom film Figure 5 is a cross-sectional view showing an example of a laminate that can be used as the bottom film for the standing pouch shown in Figure 3.

[0141] The laminate 20 shown in Figure 5 can be used as the bottom film 112. As will be described later, the laminate 20 can be modified in various ways. Laminates relating to these modified forms can also be used as the bottom film 112.

[0142] The laminate 20 includes, in this order, a protective layer 26, a base material layer 21, a printing layer 24, an adhesive layer 23A, an intermediate layer 28, an inorganic compound layer 25, a coating layer 27, an adhesive layer 23B, and a sealant layer 22.

[0143] As described later, the base layer 21, the intermediate layer 28, and the sealant layer 22 contain polyethylene. Preferably, the laminate 20 contains 90% by mass or more polyethylene. By having a polyethylene content of 90% by mass or more, high recyclability can be achieved.

[0144] <3.1> Base material layer The base layer 21 is a second base layer. The base layer 21 contains polyethylene. Preferably, the base layer 21 is made of polyethylene.

[0145] As described above, the crystallinity of the base layer 21 is lower than that of the base layer 11. Preferably, the crystallinity of the base layer 21 is in the range of 5% to 35%. More preferably, the crystallinity of the base layer 21 is 10% or more. Furthermore, more preferably, the crystallinity of the base layer 21 is 30% or less.

[0146] The base layer 21 may be an unstretched film or a stretched film. It is preferable that the base layer 21 be an unstretched film.

[0147] Except for the points mentioned above, the base layer 21 can be configured in the same way as described above for the base layer 11.

[0148] <3.2>Sealant layer The sealant layer 22 is a second sealant layer. The sealant layer 22 faces the substrate layer 21. The sealant layer 22 contains polyethylene. Preferably, the sealant layer 12 is made of polyethylene. The sealant layer 22 can have the same configuration as the sealant layer 12 described above.

[0149] <3.3>Printing layer The printed layer 24 is the second printed layer. The printed layer 24 is provided on the surface of the substrate layer 21 facing the sealant layer 22, that is, on the back surface of the substrate layer 21. The position where the printed layer 24 is provided is not limited. That is, the printed layer 24 may be provided on the surface of the substrate layer 21, or at any position between the substrate layer 21 and the sealant layer 22. For example, the printed layer 24 may be provided on any surface of the intermediate layer 28. Also, the laminate 20 may contain multiple printed layers. The printed layer 24 may be omitted.

[0150] The same ink as described above for the printing layer 14 can be used for the printing layer 24. The printing layer 24 can be formed in the same manner as described above for the printing layer 14.

[0151] <3.4> Middle Class The intermediate layer 28 is a second intermediate layer. The intermediate layer 28 is provided between the base layer 21 and the sealant layer 22. Here, the intermediate layer 28 is provided between the base layer 21 and the sealant layer 22 such that the printing layer 24 is interposed between the base layer 21 and the intermediate layer 28. The intermediate layer 28 can be omitted.

[0152] The intermediate layer 28 contains polyethylene. As the polyethylene, for example, the polyethylene described above for the polyethylene contained in the base layer 11 can be used.

[0153] The intermediate layer 28 can employ the same configuration as described above for the intermediate layer 18. The intermediate layer 28 can be manufactured in the same manner as described above for the intermediate layer 18.

[0154] <3.5>Inorganic compound layer The inorganic compound layer 25 is a second inorganic compound layer. The inorganic compound layer 25 is provided on one side of the intermediate layer 28. Here, the inorganic compound layer 25 is provided on the side of the intermediate layer 28 facing the sealant layer 22. The inorganic compound layer 25 may also be provided on the side of the intermediate layer 28 facing the substrate layer 21. The inorganic compound layer 25 may be provided on the side of the substrate layer 21 facing the sealant layer 22, here between the substrate layer 21 and the printing layer 24. The inorganic compound layer 25 may be provided on the side of the substrate layer 21 opposite to the sealant layer 22, here as the outermost layer of the laminate. The inorganic compound layer 25 can be omitted.

[0155] The inorganic compound layer 25 can employ the same configuration as described above for the inorganic compound layer 15. The inorganic compound layer 25 can be formed in the same manner as described above for the inorganic compound layer 15.

[0156] Metal vapor-deposited films, such as aluminum, are suitable for disposal. If the required light-shielding and barrier performance are met, an aluminum vapor-deposited film can be used instead of the inorganic compound layer 25. The thickness of the aluminum vapor-deposited layer is preferably 40 nm to 80 nm. The aluminum vapor-deposited layer can be provided in the intermediate layer 28, the substrate layer 21, or the sealant layer 22. When the aluminum vapor-deposited layer is provided in the sealant layer 22, it is preferably about 40 nm thick, and when it is provided in the intermediate layer 28 or the substrate layer 21, it is preferably about 80 nm thick.

[0157] <3.6> Covering layer The coating layer 27 is a second coating layer. The coating layer 27 coats the inorganic compound layer 25. The laminate of the inorganic compound layer 25 and the coating layer 27 constitutes a second gas barrier layer that improves the oxygen barrier and water vapor barrier properties of the laminate 20. The second gas barrier layer may contain only the inorganic compound layer 25, or only the coating layer 27. The laminate 20 may not contain the second gas barrier layer.

[0158] The coating layer 27 can employ the same configuration as described above for the coating layer 17. The coating layer 27 can be formed in the same manner as described above for the coating layer 17.

[0159] <3.7>Adhesive layer Adhesive layer 23A bonds the substrate layer 21, on which the printed layer 24 is provided, to the intermediate layer 28. Adhesive layer 23B bonds the intermediate layer 28, on which the inorganic compound layer 25 and the coating layer 27 are provided, to the sealant layer 22. If the intermediate layer 28 is omitted, one of the adhesive layers 23A or 23B can be omitted.

[0160] Adhesive layers 23A and 23B consist of the same adhesive as described above for adhesive layers 13A and 13B. Adhesive layers 23A and 23B can employ the same configuration as described above for adhesive layers 13A and 13B. Adhesive layers 23A and 23B can be formed in the same manner as described above for adhesive layers 13A and 13B.

[0161] <3.8>Protective layer The protective layer 26 is a second protective layer. The protective layer 26 is the outermost layer of the laminate 20 and covers the back surface of the surface of the base layer 21 facing the sealant layer 22. The protective layer 26 may be omitted.

[0162] The protective layer 26 can employ the same configuration as described above for the protective layer 16. The protective layer 26 can be formed in the same manner as described above for the protective layer 16.

[0163] <3.9> Other layers The laminate 20 may further include one or more other layers. For example, the laminate 20 may further include an anchor coat layer covering the surface on which the inorganic compound layer 25 of the intermediate layer 28 is formed. Alternatively, the laminate 20 may further include an anchor coat layer covering the surface of the base layer 21 facing the adhesive layer 23A. Alternatively, the laminate 20 may further include an anchor coat layer covering the surface on which the inorganic compound layer 15 of the intermediate layer 28 is formed, and an anchor coat layer covering the surface of the base layer 21 facing the adhesive layer 23A. The anchor coat layer of the laminate 10 can be formed using the anchor coat agent described above.

[0164] <4> effect The above-mentioned standing pouch 110 is less prone to defects during manufacturing, and the packaged article 100, which is filled with contents 120, is less likely to develop pinholes in the film during distribution. This will be explained below.

[0165] The main cause of pinholes in the film of packaged goods, which consist of contents filled into standing pouches, is the repeated contact between the film and packaging materials such as cardboard during distribution, particularly during transportation. More specifically, when multiple standing pouches are packed side by side in packaging materials such as cardboard, the film of the standing pouch comes into contact with the inner surface of the cardboard packaging. During distribution and transportation in this state, the film and the inner surface of the cardboard continue to rub against each other due to vibrations during transportation. In addition, the film of the standing pouch itself is folded by the contents it is filled with and by other standing pouches, and is repeatedly bent by vibrations. These frictions and bends cause pinholes to form in the film.

[0166] Body films with a low degree of crystallinity have low impact strength and puncture resistance. Therefore, such body films are prone to developing pinholes during the distribution of packaged goods.

[0167] Furthermore, the bottom film has infrequent contact with other packaging materials. Therefore, the risk of pinholes forming in the bottom film during the distribution of packaged goods is small.

[0168] In the above-described packaged article 100, the degree of crystallinity of the base layer 11 is sufficiently greater than that of the base layer 21. Therefore, the packaged article 100 is less likely to develop pinholes in the film during distribution.

[0169] In addition, in the manufacturing of standing pouches, the laminate used as the bottom film is folded in half. Then, the folded laminate is sandwiched between a pair of laminates that will be used as the main film, and they are heat-sealed.

[0170] The bag-making machine used to manufacture standing pouches performs, for example, a heat-sealing process and a cutting process in this order. In the heat-sealing process, a laminate 20 that has been folded in half so that it is folded in a mountain fold when viewed from the sealant layer 22 during the conveying process is sandwiched between a pair of laminates 10 that are being conveyed with the sealant layers 12 facing each other, and these are heat-sealed with a heat-sealing bar. Specifically, bottom sealing, point sealing, and side sealing are performed, thereby forming heat-sealed sections HS1, HS4, HS2A, and HS2B. Note that the length direction of heat-sealed section HS1 is perpendicular to the conveying direction. In the cutting process, the composite obtained by heat sealing is cut into individual standing pouches 110.

[0171] The packaged article 100 can be manufactured, for example, using a filling machine that performs a filling process and a heat sealing process in this order. In the filling process, the contents 120 are filled into the standing pouch 110. In the heat sealing process, the opening of the standing pouch 110 is heat-sealed with a heat sealing bar to form a heat-sealed portion HS3. The packaged article 100 is obtained in this manner.

[0172] Substrate layers with a high degree of crystallinity shrink significantly when subjected to heat during processes such as heat sealing. Therefore, laminates containing substrate layers with a high degree of crystallinity are prone to warping when heat is applied.

[0173] If the base layer of the laminate used as the main film and the base layer of the laminate used as the bottom film have a high degree of crystallinity, and all of these laminates warp significantly due to heat, the risk of defective products and problems with manufacturing equipment increases. Furthermore, if all of these laminates are prone to warping due to heat, it becomes difficult to adjust the manufacturing conditions to prevent the above-mentioned problems.

[0174] In the standing pouch 110 described above, the degree of crystallinity of the base layer 21 is sufficiently lower compared to the degree of crystallinity of the base layer 11. Therefore, in the manufacturing of the standing pouch 110, the laminate 20 used as the bottom film 112 does not warp significantly due to heat. Consequently, the standing pouch 110 is less prone to defects or problems with the manufacturing equipment during its production.

[0175] Furthermore, in the standing pouch 110, the polyethylene content of each of the main film 111A and 111B and the bottom film 112 can be set to 90% by mass or more. Such a standing pouch 110 also has excellent recyclability. [Examples]

[0176] The results of tests conducted in connection with the present invention are described below. (1) Manufacturing of standing pouches (1.1) Example 1 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method.

[0177] (1.1.1) Manufacturing of the laminate to be used as the main film The laminates 10, to be used as the main films 111A and 111B, were manufactured using the following method. The printing layer 14 and protective layer 16 were omitted in this example.

[0178] As the base layer 11, a linear low-density polyethylene film, which is an ethylene-α-olefin copolymer, was used, with a thickness of 25 μm and a crystallinity of 54.1%. The crystallinity shown in this example, as well as in the examples and comparative examples described below, was measured using the measurement method described above.

[0179] As the intermediate layer 18, an unoriented high-density polyethylene film with a thickness of 32 μm and corona-treated on both sides was used. An anchor coat layer (not shown), an inorganic compound layer 15, and a coating layer 17 were sequentially formed on one side of the intermediate layer 18.

[0180] In forming the anchor coat layer, the anchor coat agent was first prepared by the following method. Specifically, an acrylic polyol and tolylene diisocyanate were mixed such that the number of NCO groups of tolylene diisocyanate was equal to the number of OH groups of the acrylic polyol, and the mixture was diluted with ethyl acetate so that the total solid content (total amount of acrylic polyol and tolylene diisocyanate) was 5% by mass. To the diluted mixture, β-(3,4-epoxycyclohexyl)trimethoxysilane was further added in an amount of 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and the mixture was then prepared by mixing these together.

[0181] Next, the anchor coating agent prepared by the above method was applied to one side of the intermediate layer 18 that had been corona-treated using the gravure coating method. This application was carried out so that the thickness of the dry coating film was 0.1 μm. In this way, the anchor coating layer was formed.

[0182] As the inorganic compound layer 15, transparent silicon dioxide (SiO₂) is deposited using an electron beam heating vacuum deposition apparatus. x A vapor-deposited film was formed on the anchor coat layer to a thickness of 40 nm. The O / Si ratio of the vapor-deposited film was set to 1.8 by adjusting the type of material used for vapor deposition.

[0183] In forming the coating layer 17, first, the coating solution for forming the coating layer was prepared by the following method. Specifically, a coating solution for forming a coating layer containing an organic-inorganic mixture (hereinafter also simply referred to as "coating solution") was prepared by mixing the following solutions A, B, and C in a mass ratio of 70 / 20 / 10, respectively. Solution A: A hydrolysis solution with a solid content of 5% by mass (SiO2 equivalent) obtained by adding 72.1 g of 0.1 N hydrochloric acid to 17.9 g of tetraethoxysilane (Si(OC2H5)4) and 10 g of methanol, and stirring for 30 minutes. Solution B: 5% by mass of polyvinyl alcohol in water / methanol solution (water:methanol mass ratio is 95:5). Solution C: A hydrolysis solution obtained by diluting 1,3,5-tris(3-trialkoxysilylpropyl) isocyanurate with a mixture of water and isopropyl alcohol (water:isopropyl alcohol mass ratio is 1:1) to a solid content of 5% by mass.

[0184] Next, the coating solution for forming the coating layer, prepared as described above, was applied to the inorganic compound layer 15 so that the thickness of the dry coating film was 0.3 μm. In this way, a coating layer 17 made of an organic-inorganic mixture was formed.

[0185] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the side of the intermediate layer 18 opposite to the side on which the inorganic compound layer 15 was formed, to form an adhesive layer 13A. Subsequently, the base layer 11 and the intermediate layer 18 were bonded together with the adhesive layer 13A in between.

[0186] As the sealant layer 12, an unstretched linear low-density polyethylene film with a thickness of 120 μm was used. A dry laminating adhesive (urethane-based adhesive) was applied to one side of the sealant layer 12 to form an adhesive layer 13B. Then, the sealant layer 12 and the coating layer 17 faced each other with the adhesive layer 13B in between, and the sealant layer 12 was laminated to a composite including the base layer 11 and the intermediate layer 18. The laminate 10 was manufactured in the manner described above.

[0187] (1.1.2) Manufacturing of laminates to be used as bottom films The laminate 20 to be used as the bottom film 112 was manufactured using the following method. In this case, the printing layer 24 and the protective layer 26 were omitted.

[0188] As the base layer 21, a high-density polyethylene film with a thickness of 30 μm and a crystallinity of 23.2% was used.

[0189] The sealant layer 22 and the intermediate layer 28 were the same materials used as the sealant layer 12 and the intermediate layer 18 in (1.1.1), respectively. The inorganic compound layer 25, the coating layer 27, the anchor coat layer, the adhesive layer 23A, and the adhesive layer 23B were the same materials used as the inorganic compound layer 15, the coating layer 17, the anchor coat layer, the adhesive layer 13A, and the adhesive layer 13B in (1.1.1), respectively.

[0190] Then, the laminate 20 was manufactured in the same manner as described above for the laminate 10 in (1.1.1).

[0191] (1.1.3) Bag making Two rolls, each made from laminate 10, and a roll made from laminate 20 were installed in the bag-making machine. The bag-making machine was then operated to produce a standing pouch 110 with dimensions of 240 mm in length, 160 mm in width, a seal width of 5 mm, a bottom seal fold width of 40 mm, and capable of holding 800 mL of contents.

[0192] The bag-making machine used here performs the heat-sealing process and the cutting process in this order. In the heat-sealing process, the laminated body 20, which has been folded in half so that it is folded in a mountain fold when viewed from the sealant layer 22 during the conveying process, is sandwiched between a pair of laminated bodies 10 that are being conveyed with the sealant layers 12 facing each other, and these are heat-sealed with a heat-sealing bar. Specifically, bottom sealing, point sealing, and side sealing are performed, thereby forming heat-sealed sections HS1, HS4, HS2A, and HS2B. The length direction of the heat-sealed section HS1 is perpendicular to the conveying direction. In the cutting process, the composite obtained by heat sealing is cut into individual standing pouches 110.

[0193] (1.2) Example 2 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method. Specifically, in this example, instead of using a linear low-density polyethylene film with a thickness of 25 μm and a crystallinity of 54.1% as the base layer 11, a high-density polyethylene film with a thickness of 25 μm and a crystallinity of 55.9% was used. Except for this point, the standing pouch 110 was manufactured in the same manner as in Example 1.

[0194] (1.3) Example 3 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method. Specifically, in this example, for the laminate 10 as the main film, the intermediate layer 18, adhesive layer 13A, anchor coat layer, inorganic compound layer 15, and coating layer 17 were omitted, and the base layer 11 and sealant layer 12 were bonded together via the adhesive layer 13B. Also, for the laminate 20 as the bottom film, the intermediate layer 28 was left as is, but the anchor coat layer, inorganic compound layer 25, and coating layer 27 were omitted. Except for these points, the standing pouch 110 was manufactured in the same manner as in Example 1.

[0195] (1.4) Example 4 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method. Specifically, for the laminate 20 as the bottom film, an anchor coat layer, an inorganic compound layer, and a coating layer were sequentially formed on the base layer 21, similar to those formed on the intermediate layer 28 in Example 1. However, the intermediate layer 28 and the adhesive layer 23A, inorganic compound layer 25, and coating layer 27 formed on it were omitted, and the coating layer-forming surface of the base layer 21 and the sealant layer 22 were bonded via the adhesive layer 23B. Furthermore, instead of an unoriented linear low-density polyethylene film with a thickness of 120 μm, an unoriented linear low-density polyethylene film with a thickness of 150 μm was used as the sealant layer 22. Except for these points, the standing pouch 110 was manufactured in the same manner as in Example 1.

[0196] (1.5) Example 5 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method. Specifically, for the laminate 10 as the main film, an anchor coat layer, an inorganic compound layer, and a coating layer were sequentially formed on the base layer 11, similar to those formed on the intermediate layer 18 in Example 1. However, the intermediate layer 18 and the adhesive layer 13A, inorganic compound layer 15, and coating layer 17 formed on it were omitted, and the coating layer-forming surface of the base layer 11 and the sealant layer 12 were bonded via the adhesive layer 13B. Furthermore, for the laminate 20 as the bottom film, an anchor coat layer, an inorganic compound layer, and a coating layer were sequentially formed on the base layer 21, similar to those formed on the intermediate layer 28 in Example 1. However, the intermediate layer 28 and the adhesive layer 23A, inorganic compound layer 25, and coating layer 27 formed on it were omitted, and the coating layer-forming surface of the base layer 21 and the sealant layer 22 were bonded via the adhesive layer 23B. Aside from these points, in this example, the standing pouch 110 was manufactured using the same method as in Example 1.

[0197] (1.6) Example 6 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method. Specifically, in this example, instead of using an unstretched, high-density polyethylene film with a thickness of 32 μm and corona-treated on both sides as the intermediate layer 18 for the laminate 10 as the main film, a biaxially oriented, low-density polyethylene film with a thickness of 25 μm was used. Except for this point, the standing pouch 110 was manufactured in the same manner as in Example 1.

[0198] (1.7) Example 7 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method. Specifically, in this example, instead of using a high-density polyethylene film with a thickness of 30 μm and a crystallinity of 23.2% as the base layer 21 of the bottom film, a high-density polyethylene film with a thickness of 30 μm and a crystallinity of 27.6% was used. Except for this point, the standing pouch 110 was manufactured in the same manner as in Example 1.

[0199] (1.8) Example 8 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method. Specifically, in this example, for the laminate 10 as the main film, the coating layer 17 was omitted, and instead of using a dry laminating adhesive (urethane-based adhesive) in the adhesive layer 13B, an epoxy-amine gas barrier adhesive was used. Similarly, for the laminate 20 as the bottom film, the coating layer 27 was omitted, and instead of using a dry laminating adhesive (urethane-based adhesive) in the adhesive layer 23B, an epoxy-amine gas barrier adhesive was used. Except for these points, the standing pouch 110 was manufactured in the same manner as in Example 1.

[0200] (1.9) Example 9 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method. Specifically, for the laminate 10 as the main film, an anchor coat layer and an inorganic compound layer were sequentially formed on the base layer 11, similar to those formed on the intermediate layer 18 in Example 1. The coating layer 17, intermediate layer 18, and adhesive layer 13A were omitted, and the adhesive layer 13B was formed by using an epoxy-amine gas barrier adhesive instead of a dry laminating adhesive (urethane-based adhesive), and applying it to the inorganic compound layer. For the laminate 20 as the bottom film, an anchor coat layer and an inorganic compound layer were sequentially formed on the base layer 21, similar to those formed on the intermediate layer 28 in Example 1. The coating layer 27, intermediate layer 28, and adhesive layer 23A were omitted, and the adhesive layer 23B was formed by using an epoxy-amine gas barrier adhesive instead of a dry laminating adhesive (urethane-based adhesive), and applying it to the inorganic compound layer. Aside from these points, in this example, the standing pouch 110 was manufactured using the same method as in Example 1.

[0201] (1.10) Example 10 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method. Specifically, in this example, for the laminate 10 as the main film, the anchor coat layer, inorganic compound layer 15, and coating layer 17 were omitted, and instead of using a dry laminating adhesive (urethane-based adhesive) in the adhesive layer 13B, an epoxy-amine gas barrier adhesive was used. Similarly, for the laminate 20 as the bottom film, the anchor coat layer, inorganic compound layer 25, and coating layer 27 were omitted, and instead of using a dry laminating adhesive (urethane-based adhesive) in the adhesive layer 23B, an epoxy-amine gas barrier adhesive was used. Except for these points, the standing pouch 110 was manufactured in the same manner as in Example 1.

[0202] (1.11) Example 11 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method. Specifically, for the laminate 10 as the main film, a protective layer 16 with a thickness of 1 μm was formed on the side of the substrate layer 11 opposite to the intermediate layer lamination surface using an organic solvent solution of polyamide-imide resin (non-volatile component concentration 5% by mass). Similarly, for the laminate 20 as the bottom film, a protective layer 26 with a thickness of 1 μm was formed on the side of the substrate layer 21 opposite to the intermediate layer lamination surface using an organic solvent solution of polyamide-imide resin (non-volatile component concentration 5% by mass). Except for these points, the standing pouch 110 was manufactured in the same manner as in Example 1.

[0203] (1.12) Example 12 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method. Specifically, in this example, the laminate 10, which serves as the main film, was provided with a 40 nm thick aluminum vapor-deposited layer instead of the inorganic compound layer 15. The laminate 20, which serves as the bottom film, was provided with a 40 nm thick aluminum vapor-deposited layer instead of the inorganic compound layer 25. Except for these points, the standing pouch 110 was manufactured in the same manner as in Example 1.

[0204] (1.13) Example 13 The standing pouch 110, as described with reference to Figures 1 to 5, was manufactured by the following method. Specifically, in this example, for the laminate 10 as the main film, the intermediate layer 18, the adhesive layer 13A, the inorganic compound layer 15, and the coating layer 17 provided thereon were omitted. Then, an aluminum vapor-deposited layer with a thickness of 80 nm was formed on one side of the sealant layer 12, and the aluminum vapor-deposited layer surface and the base layer 11 were bonded together via the adhesive layer 13B. Instead of a dry laminating adhesive (urethane adhesive), a urethane-based gas barrier adhesive was used for the adhesive layer 13B. Furthermore, for the laminate 20 as the bottom film, the intermediate layer 28, the adhesive layer 23A, the inorganic compound layer 25, and the coating layer 27 provided thereon were omitted. Then, an aluminum vapor-deposited layer with a thickness of 80 nm was formed on one side of the sealant layer 22, and the aluminum vapor-deposited layer surface and the base layer 21 were bonded together via the adhesive layer 23B. In the adhesive layer 23B, a urethane-based gas barrier adhesive was used instead of a dry laminating adhesive (urethane-based adhesive). Except for these points, the standing pouch 110 was manufactured in this example using the same method as in Example 1.

[0205] (1.14) Comparative Example 1 In the laminate for forming the main film, instead of using a linear low-density polyethylene film with a thickness of 25 μm and a crystallinity of 54.1% as the base layer, a high-density polyethylene film with a thickness of 30 μm and a crystallinity of 23.2% was used. Except for this point, in this example, the standing pouch was manufactured in the same manner as in Example 1.

[0206] (1.15) Comparative Example 2 In the laminate for forming the bottom film, instead of using a high-density polyethylene film with a thickness of 30 μm and a crystallinity of 23.2% as the base layer, a linear low-density polyethylene film with a thickness of 25 μm and a crystallinity of 54.1% was used. Except for this point, the standing pouch was manufactured in this example using the same method as in Example 1.

[0207] (1.16) Comparative Example 3 In the laminate for forming the main film, instead of using a linear low-density polyethylene film with a thickness of 25 μm and a crystallinity of 54.1% as the base layer, a high-density polyethylene film with a thickness of 25 μm and a crystallinity of 55.9% was used. Similarly, in the laminate for forming the bottom film, instead of using a high-density polyethylene film with a thickness of 30 μm and a crystallinity of 23.2% as the base layer, a linear low-density polyethylene film with a thickness of 25 μm and a crystallinity of 54.1% was used. Except for these points, in this example, the standing pouch was manufactured using the same method as in Example 1.

[0208] (1.17) Comparative Example 4 In the laminate for forming the main film, instead of using a linear low-density polyethylene film with a thickness of 25 μm and a crystallinity of 54.1% as the base layer, a high-density polyethylene film with a thickness of 30 μm and a crystallinity of 23.2% was used. Similarly, in the laminate for forming the bottom film, instead of using a high-density polyethylene film with a thickness of 30 μm and a crystallinity of 23.2% as the base layer, a linear low-density polyethylene film with a thickness of 25 μm and a crystallinity of 54.1% was used. Except for these points, in this example, a standing pouch was manufactured using the same method as in Example 1.

[0209] (1.18) Comparative Example 5 In the laminate for forming the main film, instead of using a linear low-density polyethylene film with a thickness of 25 μm and a crystallinity of 54.1% as the base layer, a high-density polyethylene film with a thickness of 30 μm and a crystallinity of 23.2% was used. Similarly, in the laminate for forming the bottom film, instead of using a high-density polyethylene film with a thickness of 30 μm and a crystallinity of 23.2% as the base layer, a high-density polyethylene film with a thickness of 25 μm and a crystallinity of 55.9% was used. Except for these points, in this example, the standing pouch was manufactured using the same method as in Example 1.

[0210] (2.1) Evaluation during bag making For each of Examples 1 to 13 and Comparative Examples 1 to 5, the occurrence of defects during the bag-making process of the standing pouch 110 was investigated. The occurrence of defects during bag-making was evaluated based on the following criteria. A: Good product rate of 90% or more B: Good product rate 80% or more but less than 90% C: Good product rate is less than 80%.

[0211] (2.2) Evaluation using a gel flex tester For each of Examples 1 to 13 and Comparative Examples 1 to 5, a pinhole test was performed on the laminate used for the main film using a Gelboflex tester. The conditions were as follows: The number of pinholes that occurred was counted, and those with fewer than 10 observed pinholes were classified as A, and those with 10 or more were classified as B.

[0212] (Gelboflex Test (GF Test)) A Gelboflex tester (a repetitive local bending fatigue testing device for evaluating the pinhole resistance of plastic films) manufactured by Tester Industries Co., Ltd. was used to perform 1500 bending cycles on each laminate at room temperature (23°C). The test specimen size was 290 mm x 200 mm in a cylindrical shape, with a head diameter of 89 mm and a torsion angle of 440°. Each movement (stroke) consisted of a 440° rotation followed by a 63.5 mm horizontal movement, with a reciprocating speed of 40 cycles / minute. After bending, the laminate was attached to a backing sheet, a liquid pinhole checker was applied, and the number of pinholes was counted by observing the seepage of the checker onto the backing sheet.

[0213] The results are shown in Tables 1 through 3 below.

[0214] [Table 1]

[0215] [Table 2]

[0216] [Table 3]

[0217] As shown in Tables 1 to 3, Examples 1 to 15 and Comparative Examples 2 and 3 all received a GF test result of A, indicating that the risk of pinholes occurring during distribution of packaged articles filled with contents in standing pouches is considered low.

[0218] As shown in Table 3, Comparative Examples 1 to 5 were prone to pinholes during the distribution of packaged goods or frequently experienced defects during bag making. In contrast, Examples 1 to 13 were less prone to pinholes during the distribution of packaged goods and did not frequently experience defects during bag making. Substrate layers with a high degree of crystallinity shrink significantly when heated during bag making. If the crystallinity of the substrate layers of both the main film and the bottom film is 35% or higher, the films will curl due to the effects of heat near the heat seal unit where they are supplied to the bag-making apparatus, reducing the yield rate of good bags. More specifically, the proportion of bags that do not become normal packaging bags due to the film being folded or shifted during the sealing process increases. While the yield rate can be increased by adjusting the bag-making equipment, such as by reducing the bag-making speed, if the crystallinity of the base layer of the bottom film is less than 15 points lower than the crystallinity of the base layer of the main film, or if the crystallinity of the base layer of the bottom film is less than 35%, then even under normal bag-making conditions, no defects will occur during bag making, and the resulting packaged goods will be less likely to develop pinholes during distribution. [Explanation of Symbols]

[0219] 10...Laminate, 11...Base layer, 12...Sealant layer, 13A...Adhesive layer, 13B...Adhesive layer, 14...Printed layer, 15...Inorganic compound layer, 16...Protective layer, 17...Coating layer, 18...Intermediate layer, 20...Laminate, 21...Base layer, 22...Sealant layer, 23A...Adhesive layer, 23B...Adhesive layer, 24...Printed layer, 25...Inorganic compound layer, 26...Protective layer, 27...Coating layer, 28...Intermediate layer, 100...Packaged article, 100A...Packaged article, 110...Standing pouch, 111A...Main film, 111B...Main film, 112...Bottom film, 113...Spout, 114...Cap, 120...Contents, HS1...Heat seal section, HS2A...Heat seal section, HS2B...Heat seal section, HS3...Heat seal section, HS4...Heat seal section, MF...Mountain fold section.

Claims

1. It comprises a pair of main body films and a bottom film, Each of the pair of main body films comprises a first substrate layer containing polyethylene and a first sealant layer provided on the first substrate layer and containing polyethylene. The bottom film comprises a second base layer containing polyethylene and a second sealant layer provided on the second base layer and containing polyethylene. A standing pouch in which the degree of crystallinity of the first substrate layer of each of the pair of main body films is greater than that of the second substrate layer, and the difference between them is 15% or more.

2. It comprises a pair of main body films and a bottom film, Each of the pair of main body films comprises a first substrate layer containing polyethylene and a first sealant layer provided on the first substrate layer and containing polyethylene. The bottom film comprises a second base layer containing polyethylene and a second sealant layer provided on the second base layer and containing polyethylene. A standing pouch in which the crystallinity of the first substrate layer of each of the pair of main films is in the range of 40% to 95%, and the crystallinity of the second substrate layer is in the range of 5% to 35%.

3. The standing pouch according to claim 1, wherein each of the pair of main body films further comprises a first intermediate layer containing polyethylene, which is interposed between the first base material layer and the first sealant layer.

4. The standing pouch according to claim 1, wherein the bottom film is interposed between the second base material layer and the second sealant layer and further comprises a second intermediate layer containing polyethylene.

5. The standing pouch according to claim 1, wherein each of the pair of main body films further includes a first protective layer as the outermost layer facing the first sealant layer with the first substrate layer in between.

6. The standing pouch according to claim 5, wherein the first protective layer comprises a cured product of a thermosetting resin.

7. The standing pouch according to claim 1, wherein the bottom film further includes a second protective layer as the outermost layer facing the second sealant layer with the second substrate layer in between.

8. The standing pouch according to claim 7, wherein the second protective layer comprises a cured product of a thermosetting resin.

9. The standing pouch according to claim 1, wherein each of the pair of main body films further includes a first gas barrier layer interposed between the first substrate layer and the first sealant layer.

10. The standing pouch according to claim 1, wherein the bottom film further comprises a second gas barrier layer interposed between the second substrate layer and the second sealant layer.

11. The standing pouch according to claim 1, wherein each of the pair of main body films and the bottom film has a polyethylene content of 90% by mass or more.

12. A standing pouch according to claim 1 for containing contents having a volume in the range of 0.2 L to 4.0 L.

13. A standing pouch according to any one of claims 1 to 11, The contents contained in the aforementioned standing pouch and Packaged articles equipped with [a specific feature / feature].

14. The packaged article according to claim 13, wherein the volume of the contents is in the range of 0.2 L to 4.0 L.

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