Stacked body and stand-up pouch

Abstract

The laminate disclosed herein comprises a substrate layer and a heat-sealing layer. After applying a crease to the laminate using the weight of a 2 kg roller, the bending angle centered on the crease is 20–55°. The polyethylene content in the laminate is 90% by mass or more. The bending angle can also be 25–55°. The substrate layer may contain high-density polyethylene. The substrate layer may be a uniaxially stretched linear low-density polyethylene film or an unstretched film composed of polyethylene.

Description

Technical Field

[0001] This disclosure relates to laminates for packaging, and more particularly to laminates applicable to stand-up pouches. Background Technology

[0002] Depending on the nature and quantity of the contents to be packaged, the post-processing to prevent spoilage, the method of handling the packaging, the method of opening the packaging, and the method of discarding the packaging, various materials are used in combination for packaging.

[0003] For example, stand-up pouches make merchandise more visible on store shelves, and their applications are expanding. To ensure that stand-up pouches don't fold in the middle and remain fully visible, the laminated structure of the pouch must be rigid. Additionally, if the contents are liquid, the pouch must be strong enough not to tear upon drop. To meet these requirements, laminates made of polyester film, nylon film, polyolefin film, etc., can be used.

[0004] However, due to increased awareness of environmental issues in recent years, various products are required to have functions such as resource conservation and reuse, and laminated bodies used for packaging are also required to have the same functions.

[0005] One method for reusing laminates composed of various materials is to separate each of the individual materials. However, separating the laminates, which have been given a predetermined strength as a packaging material, requires various thermal, chemical, and mechanical processes. Furthermore, the classification of the separated materials must be carried out using physical methods such as specific gravity and different optical methods for each material. However, the more precise the separation and classification, the more energy is required, making the process inefficient.

[0006] Other methods include constructing a base laminate from materials of the same system and reusing the laminate as a single material. Thermoplastic resins, in particular, include materials from various systems such as polyolefins, polyesters, and polyamides. Each of these materials can be endowed with various properties through processes such as molecular weight or molecular weight distribution, heat treatment, orientation, and stretching. Polyolefin materials, especially, have low melting points, resulting in good processability; and they are easy to use because they are manufactured using copolymers. Therefore, various methods have been proposed to date.

[0007] Patent Document 1 discloses a laminate composed of a uniaxially stretched polyolefin resin film and a polyolefin heat-sealing layer. The main objective of this invention is to create a laminate with the tear-resistant properties of a uniaxially stretched film, resulting in a laminate composed of resins from the same system. However, no specifications are provided regarding the strength of the packaging material. Patent Document 1 also mentions that biaxially stretched nylon, polyester, or other films can be laminated as needed, and the aforementioned laminate does not address issues such as environmental concerns.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent No. 5197952 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] This disclosure provides a laminate for manufacturing stand-up pouches, which is recyclable and easily extruded from the stand-up pouch. Additionally, this disclosure provides stand-up pouches manufactured using this laminate.

[0013] Solution for solving the problem

[0014] The laminate disclosed herein comprises a substrate layer and a heat-sealing layer. After applying a crease to the laminate using the weight of a 2kg roller, the bending angle centered on the crease is 20 to 55°. The polyethylene content in the laminate is 90% by mass or more.

[0015] The polyethylene content in the aforementioned laminate is 90% by mass or more, meaning that the laminate disclosed herein is essentially composed of a single material. Therefore, the laminate disclosed herein is recyclable. It should be noted that, in this disclosure, a laminate made of a single material refers to a laminate in which the mass percentage of a specific material (e.g., polyethylene) is 90% by mass or more (preferably 95% by mass or more).

[0016] The bending angle of the above-mentioned laminate after applying creases using rollers is 20–55°. According to the inventors' research, when comparing the conventional laminate (nylon film (thickness: ...) used in stand-up pouches...

[0017] When creases are applied to both the 15μm aluminum vapor-deposited PET film (thickness: 12μm) and linear low-density polyethylene film, the bending angle is greater than 60°. By keeping the bending angle below 55°, users can easily fold or roll the stand-up pouch, thus making it easier to squeeze the contents out. On the other hand, by keeping the bending angle above 20°, the laminate has a certain degree of rigidity, thus easily ensuring the stand-up pouch's self-standing posture.

[0018] The crease angle of a laminated body can be adjusted using methods such as the following.

[0019] (1) The substrate layer contains high-density polyethylene, and the content of high-density polyethylene is adjusted. As the content of high-density polyethylene increases, the crease angle tends to become larger.

[0020] (2) As the substrate layer, a stretched film such as a uniaxially stretched or biaxially stretched linear low-density polyethylene film is used. When a stretched film is used, the crease angle tends to be larger compared to the case where an unstretched film is used.

[0021] (3) The heat-sealing layer is composed of a mixture containing linear low-density polyethylene and cyclic polyolefins. As the proportion of cyclic polyolefins in the heat-sealing layer increases, the crease angle tends to become larger.

[0022] (4) An adhesive layer is provided between the substrate layer and the heat-sealing layer. The crease angle of the laminate can be adjusted by adjusting the rigidity of the adhesive layer.

[0023] The bending angle can be 25 to 55°.

[0024] The substrate layer may contain high-density polyethylene.

[0025] When the substrate layer contains high-density polyethylene, the substrate layer is more difficult to melt during heat-sealing laminate construction.

[0026] The substrate layer may be a stretched, linear low-density polyethylene film.

[0027] In this case, compared to unstretched linear low-density polyethylene (LLDPE) film, stretched linear LLDPE film has a higher melting point and can therefore withstand the heat during heat sealing. That is, it can suppress the melting of the substrate layer during heat sealing. The stretched linear LLDPE film can be uniaxially stretched or biaxially stretched.

[0028] The substrate layer may be an unstretched film made of polyethylene.

[0029] When the substrate layer is an unstretched film, the resin's orientation almost disappears, making it easy to elongate and difficult to break in the face of external stresses such as stretching or puncture.

[0030] The heat-sealing layer may be composed of materials with a density of less than 0.925 g / cm³. 3 It is composed of a mixture of linear low-density polyethylene and cyclic polyolefins.

[0031] In this case, the laminate exhibits easy opening due to tearing. When the substrate layer is an unstretched film made of polyethylene, the laminate exhibits particularly excellent easy opening due to tearing.

[0032] The aforementioned laminate may further include an adhesive layer between the substrate layer and the heat-sealing layer.

[0033] By providing such an adhesive layer, the stiffness of the laminate can be adjusted. Furthermore, by providing such an adhesive layer, the interlayer adhesion between the substrate layer and the heat-sealing layer can be improved, making delamination less likely, thereby maintaining the bag's pressure resistance and impact resistance. Additionally, when an ink layer (printing layer) or a coating layer (anchoring coating) is provided between the layers, it has the effect of imparting adhesion between the resin contained in these layers and the polyethylene of the substrate layer or heat-sealing layer (i.e., between different resins).

[0034] The stand-up pouch disclosed herein comprises the aforementioned laminated body. According to this stand-up pouch, a single material can be used, and contents can be easily extruded from the pouch. Furthermore, the stand-up pouch is easy to fold or roll, thus easily maintaining a compact size when the stand-up pouch is discarded.

[0035] The effects of the invention

[0036] According to this disclosure, a laminate for manufacturing stand-up pouches is provided, which is recyclable and easily extruded from the stand-up pouch. Additionally, according to this disclosure, a stand-up pouch manufactured using this laminate is provided. Attached Figure Description

[0037] [ Figure 1 [A schematic cross-sectional view is provided to illustrate a laminate according to one embodiment of the present disclosure.]

[0038] [ Figure 2A This is a plan view of a specimen used to determine the bending angle.

[0039] [ Figure 2B This is a side view schematically showing the state of the specimen after it has been rolled up on a horizontal plane (before creases are applied).

[0040] [ Figure 2C This is a top view illustrating the application of creases to a sample using a roller.

[0041] [ Figure 2D This is a side view showing a specimen with creases applied.

[0042] [ Figure 3 This is a front view showing one embodiment of the self-standing bag of this disclosure. Detailed Implementation

[0043] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, the present disclosure is not limited to the following embodiments.

[0044] like Figure 1As shown, the laminate 10 according to this embodiment includes a substrate layer 1 and a heat-sealing layer 2. The polyethylene content in the laminate 10 is 90% by mass or more. If the polyethylene content is 90% by mass or more, a single material can be used, and resin regeneration (recycling) becomes easy. In addition, the laminate 10 is flexible and easily elongated, thus exhibiting excellent impact resistance. The polyethylene content in the laminate 10 is more preferably 95% by mass or more, and even more preferably 98% by mass or more.

[0045] The laminate 10 is characterized by its ease of bending or rolling. Specifically, after applying a crease to the laminate 10 using the weight of a 2kg roller, the bending angle centered on the crease is 55° or less, preferably 50° or less, and more preferably 45° or less. This feature is useful for applying the laminate 10 to the manufacture of stand-up pouches. In other words, by making the bending angle 55° or less, the user can easily bend or roll the stand-up pouch, thus providing the advantage of easily squeezing the contents out of the stand-up pouch.

[0046] The laminate 10 also has the characteristic of having moderate stiffness. That is, after applying a crease to the laminate 10 using the weight of a 2kg roller, the bending angle centered on the crease is 20° or more, preferably 25° or more, more preferably 30° or more, and particularly preferably 35° or more. This characteristic is also useful for applying the laminate 10 to the manufacture of stand-up pouches. That is, by making the bending angle 20° or more, the stand-up pouch's self-standing ability is easily ensured. It should be noted that the bending angle can be defined as: bending the laminate 10, passing the roller twice along a direction orthogonal to the crease (e.g., the MD direction), and then measuring the angle α formed by the two surfaces extending from the crease to both sides three times, and the average value of the three measurements of the angle α.

[0047] It should be noted that, when the laminate 10 includes a film, from the viewpoint of easily squeezing the contents out of the stand-up pouch, the crease angle is preferably within the aforementioned range, whether the crease is applied along the MD or TD direction of the film. When squeezing the contents out of the stand-up pouch, depending on the user, the pouch is folded or rolled from the bottom toward the opening, or the two sides of the pouch are folded or rolled toward the center. When the stand-up pouch is in a horizontal position, the TD direction of the laminated film constituting the stand-up pouch is vertical, and the MD direction is horizontal.

[0048] [Substrate Layer]

[0049] The substrate layer 1 is formed of polyethylene. Examples of polyethylene include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), and low-density polyethylene (LDPE). From a melting point perspective, it is preferable to use resins with a density of 0.925 g / cm³, such as HDPE and MDPE, as the resin constituting the substrate layer 1.3 The above-mentioned resins are particularly preferred, with a density of 0.93 to 0.98 g / cm³. 3 High-density polyethylene within a certain range. In this case, the substrate layer 1 is more difficult to melt during heat-sealing of the laminate 10.

[0050] As the substrate layer 1, for example, a stretched film of LLDPE can be used. Stretching can be uniaxial or biaxial. Compared to unstretched LLDPE film, stretched LLDPE film has a higher melting point and can therefore withstand the heat during heat sealing. The density of LLDPE is, for example, less than 0.925 g / cm³. 3 It can be 0.900~0.920g / cm³ 3 .

[0051] The substrate layer 1 is an unstretched film made of polyethylene. When the substrate layer 1 is an unstretched film, the resin orientation is almost lost, making it easy to elongate under external stresses such as stretching or puncture, and difficult to break.

[0052] In the substrate layer 1, the resin is not limited to petroleum-derived resin materials, but may also include some or all of a bio-derived resin material (e.g., biomass polyethylene using ethylene from biomass as a raw material). For example, Japanese Patent Publication No. 2010-511634 discloses a method for manufacturing biomass-derived polyethylene. Alternatively, commercially available biomass polyethylene (such as Green PE manufactured by Braskem SA) may also be used. Furthermore, the substrate layer may also contain mechanically recycled polyethylene made from used polyethylene products or resin (so-called scrap) generated during the manufacturing process of polyethylene products. In addition to the aforementioned LLDPE and other polyethylenes, the substrate layer 1 may also contain other resin components as resin. Examples of other resin components include polyamide, polyethylene terephthalate, polypropylene, and polyvinyl alcohol. For example, based on the total amount of the substrate layer, such other resin components are preferably 15% by mass or less, and more preferably 10% by mass or less. The substrate layer may also partially contain biodegradable resin materials (e.g., polylactic acid, polycaprolactone, polyhydroxyalkanoates, polyglycolic acid, modified polyvinyl alcohol, casein, modified starch, etc.) as resin. The substrate layer 1 may also contain additives such as antistatic agents, ultraviolet absorbers, plasticizers, lubricants, and colorants as needed.

[0053] The thickness of the substrate layer 1 can be, for example, 10–50 μm or 20–50 μm. By adjusting the thickness of the substrate layer 1, the flexibility and rigidity of the laminate 10 can be adjusted.

[0054] [Heat-sealing layer]

[0055] The heat-sealing layer 2 is a heat-sealing layer, for example, composed of polyethylene with a melting point higher than that of the substrate layer 1. For example, linear low-density polyethylene (LLDPE) or ultra-low-density polyethylene (VLDPE) can be used as the polyethylene constituting the heat-sealing layer 2. Preferably, a polyethylene with a melting point of 0.900–0.920 g / cm³ is used. 3 The density of the polyethylene is [not specified]. From the viewpoint of heat-sealing properties, the melting point of the resin constituting the heat-sealing layer 2 is preferably in the range of 40 to 160°C, more preferably in the range of 80 to 140°C.

[0056] The heat-sealing layer 2 may contain a cyclic polyolefin. Examples of cyclic polyolefins include cyclic olefin copolymers (COCs) formed by copolymerizing norbornene and ethylene. In the aforementioned cyclic olefin copolymer, the content of norbornene, based on the total amount of monomers constituting the copolymer, is preferably 60-85% by mass, more preferably 60-80% by mass, and even more preferably 65-70% by mass. By keeping the norbornene content within the above range, heat-induced sealing can be ensured, and the ease of opening due to tearing of the laminate 10 can be further improved. The density of the cyclic polyolefin is preferably 0.95-1.05 g / cm³. 3 More preferably, it is 1.01–1.04 g / cm³. 3 By keeping the density within the aforementioned range, the ease of opening due to tearing of the laminate 10 can be further improved.

[0057] The heat-sealing layer 2 is preferably composed of a component with a density of less than 0.925 g / cm³. 3 It is composed of a mixture of linear low-density polyethylene and cyclic polyolefins. In this case, the laminate 10 has easy opening properties due to tearing. When the substrate layer 1 is an unstretched film made of polyethylene, the laminate 10 has particularly excellent easy opening properties due to tearing. As the density is less than 0.925 g / cm³... 3 Linear low-density polyethylene, preferably with a density of 0.900–0.920 g / cm³. 3 Linear low-density polyethylene.

[0058] Based on the total amount of heat-sealing layer, the content of cyclic polyolefin in heat-sealing layer 2 is preferably 1 to 30% by mass, more preferably 3 to 25% by mass, and even more preferably 5 to 20% by mass. By making the content of cyclic polyolefin 1% or more by mass, the rigidity of the laminate 10 tends to increase. On the other hand, by making the content of cyclic polyolefin 30% or less by mass, the flexibility tends to increase. In addition, the reduction in heat-sealing performance and the reduction in recyclability can also be suppressed. Furthermore, by making the content of cyclic polyolefin within the above range, the ease of opening due to tearing of the laminate 10 tends to increase.

[0059] Alternatively, based on the total amount of heat-sealing layers, the content of cyclic polyolefins in heat-sealing layer 2 can be 5% by mass or more, or 10% by mass or more. By keeping the content of cyclic polyolefins above the aforementioned lower limit, the ease of opening due to tearing of the laminate can be further improved.

[0060] The heat-sealing layer 2 may also contain other resins or additives besides the aforementioned polyethylene and cyclic polyolefins. Examples of other resins include: polypropylene, ethylene-vinyl acetate copolymer, propylene-ethylene copolymer, ethylene-1-butene copolymer, propylene-1-butene copolymer, ethylene-propylene-butadiene copolymer, and ethylene-propylene-1-butene copolymer. Examples of additives include: heat stabilizers, antioxidants, UV absorbers, anti-blocking agents, lubricants, and antistatic agents. Furthermore, the heat-sealing layer 2 may also contain biomass polyethylene made from ethylene derived from biomass. Additionally, the heat-sealing layer 2 may also contain mechanically recycled polyethylene made from used polyethylene products or resin (so-called scrap) generated during the manufacturing process of polyethylene products.

[0061] The thickness of the heat-sealing layer 2 can be, for example, 30–150 μm or 60–150 μm. By adjusting the thickness of the heat-sealing layer 2, the flexibility and rigidity of the laminate 10 can be adjusted.

[0062] As a method for forming the heat-sealing layer 2, it can be formed by various known lamination methods, such as dry lamination using a one-component or two-component curing urethane-based adhesive to bond the film-like heat-sealing layer composed of the above-mentioned materials; solvent-free dry lamination using a solvent-free adhesive to bond the film-like heat-sealing layer; extrusion lamination by heating and melting the above-mentioned materials, extruding them into a curtain shape, and bonding them; and so on. When using an adhesive, an adhesive layer, described later, is provided between the substrate layer 1 and the heat-sealing layer 2.

[0063] The following methods can be listed as general methods for laminating the substrate layer 1 and the heat-sealing layer 2 by heat treatment.

[0064] (1) A method of extruding adhesive resin between a pre-filmed substrate layer 1 and a heat-sealing layer 2 and laminating them.

[0065] (2) A method of co-extruding the heat-sealing layer 2 and the adhesive resin and laminating them with the substrate layer 1.

[0066] (3) A method of further heating / pressurizing the laminated substrate obtained by the above (1) or (2) method to bond it.

[0067] (4) The laminated substrate obtained by the above (1) or (2) method is further stored in a high temperature atmosphere or passed through a drying / sintering furnace in a high temperature atmosphere.

[0068] Examples of adhesive resins used in heat-treated lamination methods include acid-modified polyolefins. Furthermore, while the substrate layer 1 and heat-sealing layer 2 are laminated by extrusion lamination in the above method, it is also possible to pre-coat the substrate layer 1 with an acid-modified polyolefin-based coating agent (solubilizing or dispersing type) without extrusion lamination, and then laminate the heat-sealing layer 2 by heat treatment.

[0069] As described above, the laminate 10 includes a substrate layer 1 and a heat-sealing layer 2. In addition, an adhesive layer (not shown) may be provided between the substrate layer 1 and the heat-sealing layer 2. The adhesive forming the adhesive layer can be selected according to the bonding method; urethane-based adhesives, polyester-based adhesives, etc., can be used. By providing such an adhesive layer, the stiffness of the laminate can be adjusted. Furthermore, by providing such an adhesive layer, the interlayer adhesion between the substrate layer 1 and the heat-sealing layer 2 can be improved, making delamination less likely and maintaining the pressure resistance and impact resistance of the bag. Additionally, when an ink layer (printing layer) or a coating layer (anchoring coating) is provided between the layers, it has the effect of imparting adhesion between the resin contained in these layers and the polyethylene of the substrate layer 1 or the heat-sealing layer 2 (i.e., between different resins).

[0070] The adhesive layer preferably does not contain chlorine. By making the adhesive layer chlorine-free, it is possible to prevent discoloration during remelting or, for example, the development of an odor due to heat treatment. Furthermore, from an environmental perspective, the compounds contained in the adhesive are preferably made from biomass materials. Additionally, from an environmental perspective, the adhesive preferably does not contain solvents.

[0071] Furthermore, the laminate 10 according to this embodiment may also have an anchoring coating between the substrate layer 1 and the heat-sealing layer 2. The anchoring coating can improve the adhesion between the substrate layer 1 and the heat-sealing layer 2, improve the adhesion between the ink or coating agent and the polyethylene of the substrate layer or heat-sealing layer (i.e., between different resins), and improve the smoothness of the surface of the substrate layer 1. The anchoring coating can be formed using an anchoring coating forming composition (an anchoring coating agent).

[0072] Examples of anchoring agents include acrylic resins, epoxy resins, urethane acrylate resins, polyester polyurethane resins, polyether polyurethane resins, and polyvinyl alcohol resins. From the viewpoint of heat resistance and interlayer bond strength, urethane acrylate resins and polyester polyurethane resins are preferred as anchoring agents.

[0073] The thickness of the anchoring coating is not particularly limited, but it is preferably in the range of 0.01 to 5 μm, more preferably in the range of 0.03 to 3 μm, and particularly preferably in the range of 0.05 to 2 μm. When the thickness of the anchoring coating is above the aforementioned lower limit, more sufficient interlayer bond strength tends to be obtained. On the other hand, when the thickness of the anchoring coating is below the aforementioned upper limit, it tends to be easier to increase the polyethylene content in the laminate.

[0074] As a method for applying an anchoring coating on the substrate layer 1, known coating methods can be used without particular limitations, such as methods using sprayers, coating machines, printing machines, brushes, dipping methods, etc.

[0075] As the amount of the anchoring coating applied, it is calculated per 1m after the anchoring coating has been applied and dried. 2 The preferred mass is 0.01–5 g / m³. 2 More preferably, it is 0.03–3 g / m 2 After applying and drying the anchoring agent, every 1m 2 When the quality is above the aforementioned lower limit, film formation tends to become sufficient. On the other hand, when the anchoring coating is applied and dried, each 1m 2 When the quality is below the above upper limit, it tends to dry easily and the solvent is difficult to leave residue.

[0076] In addition to the substrate layer 1 and the heat-sealing layer 2, the laminate 10 may further include a barrier layer, a printing layer, and an additional PE layer. These layers may be disposed, for example, between the substrate layer 1 and the heat-sealing layer 2, or on the side of the heat-sealing layer 2 opposite to the substrate layer 1. Furthermore, when a printing layer is provided, from the viewpoint of preventing the printing layer from discoloring or producing an odor during remelting, it is preferable to use a chlorine-free substance in the printing ink. Additionally, from an environmental perspective, it is preferable that the compounds contained in the printing ink are made from biomass materials.

[0077] <Packaging Bags>

[0078] The packaging bag is formed by fabricating the aforementioned laminated body 10. The packaging bag can be formed by folding one laminated body 10 in half with the heat-sealing layers 2 facing each other, and then heat-sealing two or three sides; alternatively, it can be formed by overlapping two laminated bodies 10 with the heat-sealing layers 2 facing each other, and then heat-sealing three or four sides. The packaging bag can contain food, pharmaceuticals, or other similar products. The packaging bag can undergo heat sterilization treatments such as boiling.

[0079] Cooking is a method of moist heat sterilization for preserving food, pharmaceuticals, etc. Typically, depending on the contents, packaging bags containing food, etc., are subjected to moist heat sterilization at 60–100°C, atmospheric pressure, and for 10–120 minutes. Cooking is usually performed using a hot water bath at temperatures below 100°C. Methods include: batch processing where the bags are immersed in a hot water bath at a specific temperature for a certain time and then removed; and continuous processing where the bags pass through a hot water bath in a tunnel. The packaging bags described in this embodiment can also be used for applications requiring cooking.

[0080] The packaging bag can be a packaging bag with a curved portion (folded portion) shape. The packaging bag of this embodiment maintains high air barrier properties even with a curved portion shape. As an example of a packaging bag with a curved portion (folded portion) shape, a stand-up pouch can be cited. Stand-up pouches containing the above-described laminated body have excellent recyclability and are easy to squeeze out of their contents. Specific examples of contents include: viscous substances such as hand sanitizer, shower gel, shampoo, and conditioner. Figure 3 A front view showing one embodiment of the self-standing bag of this disclosure. Figure 3 The stand-up pouch 20 shown is formed by heat-sealing a pair of side body portions 21, 22 and a bottom tape 23. The side body portions 21, 22 and the bottom tape 23 are all composed of laminated bodies 10. The heat-sealing method for forming the stand-up pouch can be performed in the same manner as conventional methods.

[0081] The bottom strap 23 has a bend 23a. That is, when the stand-up pouch 20 is upright, the bottom strap 23 is arranged in an inverted V-shape. The bottom of the stand-up pouch 20 is composed of a first heat-sealing part 25 and a second heat-sealing part (not shown). The first heat-sealing part 25 is the part after heat-sealing the bottom of the side body part 21 and one bottom of the bottom strap 23. The second heat-sealing part is the part after heat-sealing the bottom of the side body part 22 and the other bottom of the bottom strap 23. In order to make the bottom of the area containing the contents form a curved surface, the side body parts 21, 22 and the bottom strap 23 are heat-sealed in such a way that the upper parts of the first heat-sealing part 25 and the second heat-sealing part form an arc shape.

[0082] The stand-up pouch 20 has welded portions 29 on both sides of the bottom 20b. In this embodiment, two welded portions 29 are formed vertically on one side of the stand-up pouch 20, and two welded portions 29 are also formed vertically on the other side. The welded portions 29 join the side body portion 21 and the side body portion 22 together. The welded portions 29 are the parts where the sealing layers of the side body portions 21 and 22 are partially welded together through the cut portions 28a and 28b of the bottom strap 23. The cut portions 28a and 28b of the bottom strap 23 are the area between the fold portion 23a and the bottom edge 23d, and are provided on the side edge of the bottom strap 23.

[0083] Example

[0084] The present disclosure will be described in more detail below through examples, but the present disclosure is not limited to these examples.

[0085] <Creating Layered Bodies>

[0086] (Example 1)

[0087] In the HDPE substrate layer (thickness: 35μm; density: 0.94g / cm³) 3 An LLDPE sealing layer (thickness: 100μm; density: 0.91g / cm³) is applied to the unstretched surface. 3 Thus, the laminate (two-layer structure) described in Example 1 was obtained. This laminate is essentially composed of only polyethylene. That is, the polyethylene content in this laminate is essentially 100% by mass.

[0088] (Comparative Example 1)

[0089] A conventional laminate (three-layer structure) used in stand-up pouches was prepared. Specifically, a laminate of nylon film (thickness: 15 μm) / aluminum vapor-deposited PET film (VM-PET, thickness: 12 μm) / LLDPE film (thickness: 110 μm) was prepared. The polyethylene content in this laminate was 72% by mass.

[0090] (Example 2)

[0091] <Preparation of Anchoring Coating Agent>

[0092] Acrylic polyol and toluene diisocyanate were mixed such that the number of NCO groups in toluene diisocyanate was equal to the number of OH groups in acrylic polyol, and then diluted with ethyl acetate to a total solids content (total amount of acrylic polyol and toluene diisocyanate) of 5% by mass. β-(3,4-epoxycyclohexyl)trimethoxysilane was further added to the diluted mixture to a ratio of 5 parts by mass relative to 100 parts by mass of acrylic polyol and toluene diisocyanate, and then mixed to prepare the anchoring coating agent.

[0093] <Preparation of Compositions for Heat-Sealing Layer Formation>

[0094] Linear low-density polyethylene (manufactured by Ube Maruzen Polyethylene Co., Ltd., trade name: UMERIT 2040F, density: 0.918 g / cm³) 3 MFR: 4.0 g / 10 min) and cyclic polyolefin (manufactured by POLYPLASTICS CO.,LTD., trade name: TOPAS8007, density: 1.02 g / cm³) 3A composition for heat-sealing is prepared by mixing norbornene (containing 65% by mass, hereinafter also referred to as "COC") to achieve a COC content of 20%, 15%, 10%, or 5% by mass based on the total amount of the composition.

[0095] <Creating Layered Bodies>

[0096] Using the above-mentioned anchoring coating agent, an unstretched high-density polyethylene (HDPE) film (manufactured by CharterNEX, trade name: GAP, thickness: 27 μm, density: 0.950 g / cm³) was applied as the substrate layer. 3 An anchoring coating (AC) layer with a thickness of approximately 0.3 μm was formed on the substrate (MFR: 0.83 g / 10 min, tensile modulus (MD): 773 MPa, tensile modulus (TD): 1231 MPa). Next, a heat-sealing layer forming composition with a COC content of 20% by mass was extruded onto the anchoring coating by extrusion lamination, thereby forming a heat-sealing layer with a thickness of 25 μm. Thus, a laminate consisting of a substrate layer / anchoring coating / heat-sealing layer was obtained. The polyethylene content in this laminate was 91% by mass.

[0097] <Determination of Bending Angle>

[0098] The laminates obtained in Examples 1-2 and Comparative Example 1 were cut into 50mm × 100mm pieces to obtain the sample S for testing. Figure 2A It should be noted that, Figure 2A The dashed line L in the diagram indicates the location where the crease is applied. Next, along the longitudinal direction of the sample S (MD direction or TD direction), the sample S is folded and curled in half. Figure 2B At this point, the sample S is rolled up so that the sealing layer is on the inside. Then, the roller R is passed over the sample S once or twice in the direction of arrow A, and the weight of the roller R1 of the roller R is used to create creases on the sample S. Figure 2C With a portion of the specimen S bearing the crease F fixed on the horizontal plane H, a scale is used to measure... Figure 2DThe angle α (bending angle) is the angle formed by one surface S1 and the other surface S2 extending along both sides of the crease F of the sample S. It should be noted that the following rubber roller was used as roller R1. Measurements were performed three times in both cases where roller R1 passed through once and twice. The results are shown in Table 1. Based on these results, the angle α when roller R1 passes through once or twice is preferably 20–55°. Furthermore, the bending angle is determined by bending the laminate 10, passing roller R1 twice along a direction orthogonal to the crease F (MD direction), and then measuring the angle α formed by the two surfaces S1 and S2 extending from the crease F to both sides. This operation was performed three times. The average value of the angle α obtained from the three measurements was 33.3° in Example 1, 63.3° in Comparative Example 1, and 31.7° in Example 2.

[0099] (Rubber roller)

[0100] Roller weight: 2kg

[0101] • Roller surface: Rubber (6mm thickness)

[0102] • Roller width: 45mm

[0103] • Drum diameter: 85mm

[0104] [Table 1]

[0105]

[0106] It should be noted that in a laminate containing a substrate layer and a heat-sealing layer, the heat-sealing layer comprises materials with a density of less than 0.925 g / cm³. 3 It is composed of a mixture of linear low-density polyethylene and cyclic polyolefins. When the substrate layer is an unstretched film made of polyethylene, the laminate exhibits exceptionally good tear resistance and ease of opening, regardless of the bending angle. Therefore, to illustrate this point, the following laminate was fabricated for reference, and its tear strength was measured.

[0107] <Creating Layered Bodies>

[0108] (Refer to Examples 1-3)

[0109] A heat-sealing layer was formed using a heat-sealing layer composition with a COC content of 15%, 10%, or 5% by mass, otherwise a laminate was obtained in the same manner as in Example 2.

[0110] (Refer to Example 4)

[0111] As the substrate layer, a stretched linear low-density polyethylene (LLDPE) film (manufactured by Mitsui Chemicals Tohcello, Inc., trade name: L-Smart C-1, thickness: 30 μm, density: 0.91 g / cm³) was used. 3 In addition, a laminate was obtained in the same manner as in Example 2.

[0112] (Refer to Example 5)

[0113] The substrate layer is an unstretched high-density polyethylene (HDPE) film (manufactured by Tamapoly Co., Ltd., trade name: HS31, thickness: 35μm, density: 0.948g / cm³). 3 A transparent vapor-deposited barrier film (manufactured by Toppan Printing Co., Ltd., substrate thickness: 25 μm) was formed on an HDPE substrate using a dry lamination method with a urethane adhesive, consisting of a vapor-deposited layer and a barrier layer sequentially formed on the substrate. Next, a heat-sealing layer composition with a COC content of 20% by mass was extruded onto the HDPE transparent vapor-deposited barrier film using an extrusion lamination method, thereby forming a heat-sealing layer with a thickness of 25 μm. Thus, a laminate consisting of a substrate layer, an HDPE transparent vapor-deposited barrier film, and a heat-sealing layer was obtained.

[0114] (Refer to Examples 6-8)

[0115] A heat-sealing composition with a COC content of 15%, 10%, or 5% by mass was used to form a heat-sealing layer, otherwise, a laminate was obtained in the same manner as in Reference Example 5.

[0116] (Refer to Example 9)

[0117] It uses only linear low-density polyethylene (manufactured by Ube Maruzen Polyethylene Co., Ltd., trade name: UMERIT2040F, density: 0.918 g / cm³). 3 A heat-sealing layer was formed using a heat-sealing composition consisting of MFR (4.0 g / 10 min), otherwise a laminate was obtained in the same manner as in Example 2.

[0118] (Refer to Example 10)

[0119] It uses only linear low-density polyethylene (manufactured by Ube Maruzen Polyethylene Co., Ltd., trade name: UMERIT2040F, density: 0.918 g / cm³). 3 A heat-sealing layer was formed using a heat-sealing composition consisting of MFR (4.0 g / 10 min), otherwise a laminate was obtained in the same manner as in Reference Example 5.

[0120] <Tear Strength>

[0121] The stand-up pouches obtained in Example 2 and Reference Examples 2-10 were cut into dimensions of 100 mm (MD direction) × 30 mm (TD direction). A 20 mm long slit was made in the center of the TD direction. The tear strength (unit: N) in the MD direction at a tearing speed of 5000 mm / min was determined according to the Trouser method of JIS K7128 A. The results are shown in Table 2. It should be noted that the values ​​are recorded as the average value when N=5.

[0122] [Table 2]

[0123]

[0124] Explanation of symbols

[0125] 1…substrate layer, 2…heat seal layer, 10…laminate, 20…stand-up pouch, R1…roller, F…crease

Claims

1. A laminate comprising a substrate layer and a heat-sealing layer, wherein, After applying a crease to the laminate using the weight of a 2kg roller, the bending angle centered on the crease is 20–55°. The polyethylene content in the laminate is 90% by mass or more. The substrate layer consists only of a high-density polyethylene (HDPE) film. The heat-seal layer is composed of a mixture comprising a linear low-density polyethylene having a density of less than 0.925 g / cm 3 and a cyclic polyolefin, The content of the cyclic polyolefin in the heat-sealing layer is 1 to 5% by mass.

2. The laminated body according to claim 1, wherein, The bending angle is 25° to 55°.

3. The laminate according to claim 1 or 2, wherein, An adhesive layer is further provided between the substrate layer and the heat-sealing layer.

4. A stand-up pouch comprising the laminate of any one of claims 1 to 3.

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