Laminates and packaging bags

Abstract

To provide a packaging bag that can suppress tearing when a packaging bag filled with contents is dropped. [Solution] A laminate formed from a polyolefin resin, wherein the laminate comprises at least a base layer formed from a stretched polyolefin film, an intermediate layer formed from an extruded polyolefin resin, and a sealant layer, all laminated in this order.

Description

Technical Field

[0001] The present invention relates to a laminate and a packaging bag.

Background Art

[0002] As a conventional packaging bag, a standing pouch having self-standing property in which a bottom film is disposed between a pair of body films is used. Patent Document 1 describes using a laminate film having a sealant as the innermost layer and a stretched film as a base material for a packaging bag.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, from the viewpoint of effective use of resources, it is required to use materials that can be recycled and save petroleum resources. However, a laminated film in which a plurality of materials are combined has a problem that it takes time to separate the materials and is difficult to recycle. In response to such problems, as a material suitable for recycling, a container using a film material of a single material (monomaterial) has been studied.

[0005] However, a packaging bag formed of a monomaterial film has a problem that it is easily torn when the content is filled and dropped.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a laminate capable of manufacturing a packaging bag having drop resistance and a packaging bag having drop resistance. Here, the drop resistance means a property that a packaging bag filled with a content is not easily torn when dropped. "Tearing of the packaging bag" refers to the tearing of the packaging bag due to the separation of the heat-sealed parts of the packaging, as well as the tearing of the film material that forms the packaging bag. [Means for solving the problem]

[0007] In other words, the present invention employs the following configuration. [1] A laminate formed from a polyolefin resin, wherein the laminate comprises at least a base layer formed from a stretched polyolefin film, an intermediate layer formed from an extruded polyolefin resin, and a sealant layer, all laminated in this order. [2] The laminate according to [1], wherein the polyolefin resin is polyethylene resin. [3] The laminate according to [1] or [2], wherein the base material layer and the intermediate layer are arranged directly adjacent to each other in the thickness direction of the laminate, and the intermediate layer and the sealant layer are arranged directly adjacent to each other in the thickness direction of the laminate. [4] The laminate according to any one of [1] to [3], wherein the substrate layer has a printed layer on the surface facing the intermediate layer, the printed layer and the intermediate layer are arranged directly adjacent to each other in the thickness direction of the laminate, and the intermediate layer and the sealant layer are arranged directly adjacent to each other in the thickness direction of the laminate. A packaging bag using a laminate described in any one of [5][1] to [4]. [6] The packaging bag described in [5], for packaging liquids. [7] The packaging bag according to [5] or [6], which is a standing pouch having a body film and a bottom film. The packaging bag described in [7] is a standing pouch in which the laminate described in any one of [8], [1] to [4] is used only for the body film. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a laminate capable of manufacturing drop-resistant packaging bags and drop-resistant packaging bags. Whether or not the packaging bag has drop resistance will be evaluated by a drop test, as described later. [Brief explanation of the drawing]

[0009] [Figure 1] It is a cross-sectional view of the laminate of this embodiment. [Figure 2] It is a schematic view showing an example of the packaging bag of this embodiment.

Mode for Carrying Out the Invention

[0010] <Laminate> The laminate of this embodiment is formed from a polyolefin resin. Fig. 1 shows a schematic view of a cross-section of the laminate 20 of this embodiment. The laminate 20 has a base material layer 21, an intermediate layer 22, and a sealant layer 23 laminated in this order.

[0011] It is preferable that the base material layer 21 and the intermediate layer 22 are arranged directly adjacent to each other in the thickness direction of the laminate 20, and the intermediate layer 22 and the sealant layer 23 are arranged directly adjacent to each other in the thickness direction of the laminate 22.

[0012] It is preferable that the laminate 20 has a printing layer on the surface 21a of the base material layer 21 facing the intermediate layer 22. The printing layer and the intermediate layer 22 are preferably arranged directly adjacent to each other in the thickness direction of the laminate 20, and the intermediate layer 22 and the sealant layer 23 are preferably arranged directly adjacent to each other in the thickness direction of the laminate 22.

[0013] Generally, for the material of the packaging bag, a nylon film or a polyethylene terephthalate film that is resistant to impact is used from the viewpoint of improving the drop resistance.

[0014] It is known that a stretched resin film is resistant to impact. Therefore, in developing a packaging bag with excellent drop resistance, the present inventors came up with using a stretched polyolefin as the material.

[0015] However, the packaging bag formed of a stretched polyolefin as a forming material faces the problem that the packaging bag is likely to tear along the stretching direction and is likely to tear when the packaging bag filled with the contents is dropped. As a result of intensive studies by the present inventors, it has been found that when an extruded polyolefin resin is laminated on a base material layer formed from a stretched polyolefin film, the physical properties of the base material layer change and the drop resistance of the resulting packaging bag is improved. Hereinafter, each layer will be described.

[0016] (Base material layer) The base material layer 21 is formed from a stretched polyolefin resin film, and is preferably formed from a uniaxially stretched polyolefin film. The stretching direction of the uniaxially stretched polyolefin resin film is not particularly limited, and may be the conveyance (MD) direction or the cross (TD) direction. Hereinafter, the stretched polyolefin resin film forming the base material layer 21 may be referred to as the "base material film".

[0017] Examples of the base material layer 21 include a stretched polyethylene resin film or a stretched polypropylene resin film.

[0018] The stretching ratio of the base material film is preferably in the range of, for example, 3 times or more and 8 times or less.

[0019] The polyethylene resin forming the stretched polyethylene resin film may be a homopolymer of ethylene or a copolymer mainly composed of ethylene. In order to use a material suitable for recycling, it is preferably a homopolymer of ethylene.

[0020] When using a copolymer mainly composed of ethylene (copolymer), examples of the comonomer other than ethylene include α-olefins such as 1-butene, 1-hexene, and 1-octene, cyclic olefins such as norbornene, and vinyl-based monomers such as vinyl acetate, vinyl chloride, and acrylic acid. When the polyethylene resin copolymerizes a monomer having an ester group such as vinyl acetate, a part of the ester group may be saponified to form a copolymer containing vinyl alcohol.

[0021] The ethylene or comonomers that make up the polyethylene resin may be compounds derived from fossil resources such as petroleum, or compounds derived from biomass such as plants.

[0022] To make the material suitable for recycling, it is preferable that the base layer 21 be a film made of polyethylene resin.

[0023] The polyethylene resin may include recycled polyethylene resin. The recycled polyethylene resin may be polyethylene resin produced by chemical recycling, in which used polyethylene resin is broken down into monomers such as ethylene and then repolymerized.

[0024] Alternatively, polyethylene resin produced through mechanical recycling, where used polyethylene resin is regenerated as a polymer through processes such as crushing and sorting, may be used. Recycled polyethylene resin and new polyethylene may also be mixed and used.

[0025] The base layer 21 is preferably an oriented medium-density polyethylene (MDPE) resin film or an oriented high-density polyethylene (HDPE) resin film.

[0026] The thickness of the substrate layer 21 is not particularly limited, but for example, it can be 10 μm or more and 50 μm or less, preferably 15 μm or more and 40 μm or less, and more preferably 20 μm or more and 35 μm or less.

[0027] The classification of polyethylene resins by density may be based on the classification commonly used by those skilled in the art, for example, 910 kg / m³, as in the conventional JIS K6748. 3 More than 930kg / m 3 Below 930 kg / m³ is classified as Category 1 (low density), 3 More than 942kg / m 3 Below 942 kg / m³ is classified as Category 2 (medium density), 3 The above may be classified as Type 3 (high density).

[0028] The polyethylene resin used to form the stretched polyethylene resin film may be a mixture of two or more polyethylene resins as needed.

[0029] The base layer 21 may contain additives other than resin, to the extent that they are recyclable. The additives are not particularly limited, but examples include antioxidants, lubricants, antiblocking agents, flame retardants, UV absorbers, light stabilizers, antistatic agents, colorants, and crosslinking agents. The additives may be components compatible with the resin or components incompatible with the resin.

[0030] (Middle class) The intermediate layer 22 is formed from extruded polyolefin resin. By extruding molten polyolefin resin onto the aforementioned base film, the base layer 21 and the intermediate layer 22 are laminated together.

[0031] Preferably, the monomers that substantially constitute the polyolefin resin, which is the material for forming the intermediate layer 22, are the same as the monomers that substantially constitute the polyolefin resin, which is the material for forming the base layer 21. Here, "substantially constituting monomers" refers to monomers that account for 80% or more of the total constituent units of the polyolefin resin.

[0032] For example, when polyethylene resin is used as the material for forming the base layer 21, it is preferable to use polyethylene resin as the material for forming the intermediate layer 22. Similarly, when polypropylene resin is used as the material for forming the base layer 21, it is preferable to use polypropylene resin as the material for forming the intermediate layer 22.

[0033] The extruded polyolefin resin forming the intermediate layer 22 may be a mixture of two or more polyolefin resins and may contain various additives to the extent that it is recyclable.

[0034] When polyethylene resin is used as the material for forming the intermediate layer 22, it is preferable to use linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), or a mixed resin of linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE).

[0035] Since an intermediate layer is formed by extruding molten polyolefin resin and laminating it onto a base film, heat is applied to the base film during the extrusion process.

[0036] In this embodiment, it is believed that the heat applied to the base film during the extrusion process relieves the residual stress in the base film. Furthermore, by bonding the intermediate layer 22 with extruded resin instead of adhesive, the thickness of the intermediate layer 22 occupies a certain range relative to the total thickness when the total thickness of the laminate 20 is kept the same. Such a laminate 20 is less prone to tearing in the direction parallel to the stretching direction. For this reason, it is presumed that a packaging bag using the laminate 20 is less prone to tearing when filled with contents and dropped, and therefore has drop resistance.

[0037] Whether or not the intermediate layer 22 is formed by extrusion can be confirmed by observing the cross-section of the laminate 20 that constitutes the packaging bag. If air bubbles are observed when the cross-section of the laminate 20 that constitutes the packaging bag is observed using, for example, a scanning electron microscope, it can be determined that it is formed by extrusion.

[0038] The thickness of the intermediate layer 22 is not particularly limited, but is, for example, 10 μm or more and 100 μm or less, and more preferably 20 μm or more and 80 μm or less.

[0039] (Sealant layer) The sealant layer 23 is the surface that comes into contact with the contents to be filled into the packaging bag. The sealant layers 23a on the contents side of the sealant layer 23 are heat-fused together to join the laminate 20.

[0040] The sealant layer 23 is preferably formed from an unstretched polyolefin resin film. "Unstretched polyolefin resin" refers to a material in which the polyolefin resin film itself has not been stretched. Preferably, the monomers that substantially constitute the polyolefin resin, which is the material for forming the sealant layer 23, are the same as the monomers that substantially constitute the polyolefin resin, which is the material for forming the base layer 21.

[0041] For example, when polyethylene resin is used as the material for forming the base layer 21, it is preferable to use polyethylene resin as the material for forming the sealant layer 23, and when polypropylene resin is used as the material for forming the base layer 21, it is preferable to use polypropylene resin as the material for forming the sealant layer 21.

[0042] Specific examples of materials that form the sealant layer 23 include, for example, polyethylene resins with relatively low density, such as linear low-density polyethylene (LLDPE) resin and low-density polyethylene (LDPE) resin.

[0043] The total thickness of the intermediate layer 22 and the sealant layer 23 is not particularly limited, but is, for example, 70 μm or more and 200 μm or less, and more preferably 90 μm or more and 150 μm or less.

[0044] (Optional configuration: Printed layer) The laminate 20 may include a printed layer. Preferably, the printed layer is formed on the surface 21a of the base layer 21 facing the intermediate layer 22. When the printed layer is laminated between the base layer 21 and the intermediate layer 22, it is preferable to perform oxidation treatment on at least one of the surfaces of the printed layer and the intermediate layer 22, and more preferably on both surfaces.

[0045] Furthermore, if the base layer 21 has another resin layer on the surface 21b opposite to the surface facing the intermediate layer 22, a printing layer may be laminated between the base layer 21 and the other resin layer. In another embodiment, the printed layer may be laminated on the surface 21b of the substrate layer 20 of the laminate 20, and the printed layer may be exposed on the surface.

[0046] The printed layer can be formed by printing ink in a solid or patterned manner using printing methods such as gravure printing, letterpress printing, offset printing, screen printing, or inkjet printing. The thickness of the printed layer is not particularly limited, but is typically around 0.5 to 10 μm. The printed layer may be formed over the entire surface of the laminate 20, or on a portion of the surface of the laminate 20. Two or more printed layers may be stacked on top of each other.

[0047] The ink used to form the printing layer may contain a coloring agent such as a pigment or dye, and a binder. The binder is not particularly limited, but examples include polyamide, polyurethane, polyester, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, acrylic polymer, polybutadiene, and cyclocompound rubber. The ink may also contain a solvent such as water, an organic solvent, or a vegetable oil.

[0048] (Optional configuration: barrier layer) The laminate 20 may have a barrier layer. The barrier layer has barrier properties. Barrier properties mean that it blocks external factors that cause quality degradation. Examples of external factors that cause quality degradation include water vapor, oxygen gas, organic compounds, and various other low-molecular-weight components.

[0049] Two or more barrier layers having the same or different barrier properties may be laminated together as the barrier layer. The material for forming the barrier layer is not particularly limited and may be appropriately selected from known barrier materials.

[0050] The barrier layer may be formed on the surface 21a of the base layer 21 facing the intermediate layer 22. Alternatively, the barrier layer may be laminated on the surface 21b of the base layer 21 opposite to the surface facing the intermediate layer 22. The barrier layer may also be laminated between the intermediate layer 22 and the sealant layer 23.

[0051] Furthermore, the substrate layer or sealant layer may have a multilayer structure, and a barrier layer may be included in part of it.

[0052] The thickness of the barrier layer is preferably 5 μm or less. Specific examples of the barrier layer thickness are not limited to 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.5 μm, 0.2 μm, 0.1 μm, or intermediate values ​​between these.

[0053] The barrier layer may be formed by depositing a metal such as aluminum, an inorganic compound such as silica or alumina, or diamond-like carbon (DLC) onto the outer surface of the base film, or a separate film with these deposits may be used. The film to be deposited is preferably a polyolefin film, and more preferably a stretched polyolefin film.

[0054] A metal foil may be used as a barrier layer.

[0055] A film formed from a barrier resin may be used as the barrier layer. Examples of barrier resins include ethylene vinyl alcohol copolymers.

[0056] The barrier layer may be formed by applying a barrier coating agent to a predetermined position, and a polyolefin film, or more preferably a stretched polyolefin film coated with a barrier coating agent, may be used. Such a barrier coating agent can exhibit barrier properties through drying, curing, etc.

[0057] The laminate 20 may include both a printed layer and a barrier layer.

[0058] The laminate 20 may have each layer bonded together by an adhesive layer, but it is preferable that it does not have an adhesive layer in order to facilitate recycling. In other words, it is preferable that the base layer 21 and the intermediate layer 22, and the intermediate layer 22 and the sealant layer 23 are arranged directly adjacent to each other in the thickness direction of the laminate.

[0059] For example, when laminating a substrate layer, intermediate layer, sealant layer, barrier layer, and printing layer without an adhesive layer or anchor coat layer, it is preferable to surface treat at least one surface of the layer to which each layer is laminated. Examples of surface treatments include electron beam irradiation, low-pressure plasma treatment, atmospheric pressure plasma treatment, or corona discharge treatment in an atmosphere of inert gas such as argon, helium, krypton, neon, xenon, or nitrogen, or hydrogen or oxygen. The atmospheric gas may be a mixture of the aforementioned gases as needed.

[0060] Examples of laminates are shown below. Base layer / Intermediate layer / Sealant layer Substrate layer / Printing layer / Intermediate layer / Sealant layer Printing layer / Substrate layer / Interlayer / Sealant layer Base layer / Adhesive layer / Base layer / Intermediate layer / Sealant layer Base layer / Intermediate layer / Base layer / Intermediate layer / Sealant layer

[0061] Base layer / Barrier layer / Intermediate layer / Sealant layer Barrier layer / Substrate layer / Intermediate layer / Sealant layer Base layer / Intermediate layer / Barrier layer / Sealant layer Barrier layer / Substrate layer / Barrier layer / Intermediate layer / Sealant layer

[0062] The proportion of polyolefin resin to the total amount of resin constituting the laminate 20 is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. If the proportion of polyolefin resin to the total amount of resin constituting the laminate 20 is above the above lower limit, it becomes easier to recycle.

[0063] When manufacturing the laminate 20, the composition of the raw materials is adjusted so that the ratio of polyolefin resin to the total amount of resin constituting the laminate 20 satisfies the above range.

[0064] From the viewpoint of improving the drop resistance of the packaging bag, the laminate 20 preferably has a tensile strength of 91 N / 10 mm or more, more preferably 92 N / 10 mm or more, and even more preferably 93 N / 10 mm or more, as measured by the method described in [Tensile Strength Test] below. There is no particular upper limit to the tensile strength; for example, it could be 100 N / 10 mm or less, 99 N / 10 mm or less, or 98 N / 10 mm or less.

[0065] When manufacturing the laminate 20, heat is applied to the base film during the extrusion process of the intermediate layer. At this time, the base film relaxes due to the heating, so it is presumed that the tensile strength falls within the range described above.

[0066] [Tensile strength test] The tensile strength of the laminate is determined by the following method. The laminate 20 is cut into strips 10 mm wide and 50 mm long to form test specimens. These test specimens are pulled at a constant-speed tensile testing machine at a tensile speed of 300 mm / min, and the strength at fracture is measured.

[0067] <Packaging bag> Embodiments of the present invention will be described below with reference to the drawings. Note that in the drawings used in the following description, the scale of each component may have been appropriately changed to ensure that each component is recognizable.

[0068] Figure 2 is an overall view of the packaging bag 10. The packaging bag 10 shown in Figure 2 comprises a container body 1 and a spout member 2. The packaging bag 10 may or may not have the spout member 2. The container body 1 is a standing pouch composed of, for example, two body films 51, 51 having the same planar shape as each other, and a bottom film 12.

[0069] The packaging bag 10 has a body film 51 and a bottom film 12, and at least the body film 51 uses a laminate 20.

[0070] The packaging bag 10 is preferably a standing pouch in which the laminate 20 is used only in the body film 51.

[0071] The bottom film 12 may be a laminate 20, or a film material other than the laminate 20 may be used.

[0072] When a laminate 20 is used for the bottom film, it is preferable to use a laminate 20 with a three-layer structure consisting of "stretched polyethylene resin layer / linear low-density extruded polyethylene resin layer / sealant layer" from the viewpoint of obtaining a packaging bag that is less prone to bottom tearing.

[0073] The container body 1 is provided with an inclined portion 30 at one corner of the upper part when the container is standing upright with the bottom film 12 side as the bottom.

[0074] The body films 51, 51 and the bottom film 12 are integrally formed by heat-sealing their peripheral edges. For example, the packaging bag 10 has a side seal portion 11a and a bottom seal portion 12a. The side seal portion 11a is formed by heat-sealing the side edges on both sides of the body films 51, 51. The bottom seal portion 12a is formed by heat-sealing the body films 51, 51 and the bottom film 12. The bottom film 12 is interposed between the body films 51, 51.

[0075] The contents can be filled into the storage section 10a of the packaging bag 10. When the contents are filled into the storage section 10a of the packaging bag 10, it can stand upright with the bottom film 12 facing downwards (upright position).

[0076] The contents are not particularly limited, but may include liquids, solids such as powders and granules, viscous substances, liquids, or mixtures thereof. In this embodiment, the packaging bag 10 is preferably for packaging liquids.

[0077] The dimensions of the packaging bag 10 are not particularly limited, but for example, when used as a refillable container, the height in the vertical direction is approximately 100mm to 500mm, the width in the horizontal direction is approximately 70mm to 300mm, and the filling volume is approximately 100cm³. 3 ~5000cm 3 The degree can be described as follows.

[0078] [Drop test] The drop test of the packaging bag will be conducted using the following method. First, a bottom film 12 and a pair of body films 51 are formed using the laminate 20. From these bottom film 12 and pair of body films 51, a self-standing packaging bag with a width of 130 mm and a height of 220 mm is made. The volume of the packaging bag is approximately 500 cm³. 3 Let's assume that.

[0079] After filling the packaging bag with 360g of water, the packaging bag is sealed and used as a test specimen for the drop test. The test specimen is repeatedly dropped from a height of 1 meter in a 5°C environment, five times vertically and five times horizontally. For horizontal drops, the packaging bag is dropped so that the side edge seal portion 11a around its perimeter hits the surface it falls on. For vertical drops, the bottom film 12 is dropped so that it hits the surface of the fall.

[0080] Furthermore, the height of the new test specimen will be changed to 1.2m, and similar drop tests will be conducted in both the horizontal and vertical directions.

[0081] After the fall, count the number of torn packaging bags. Here, "torn packaging bags" refers to packaging bags from which the contents (water) have leaked.

[0082] Although the present invention has been described above based on preferred embodiments, the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. Modifications include the addition, substitution, omission, and other changes to the components.

[0083] Since the laminate is mainly composed of polyolefin resin, it can be used for a variety of applications, not limited to packaging bags such as pouches, bags, and containers, or packaging films. In particular, because the laminate is flexible, it can be used to form flexible packaging bags. The packaging bag may be formed solely from the laminate described above, or it may be combined with auxiliary components such as labels, tags, straws, and outer boxes. From a recycling standpoint, it is preferable that the auxiliary components can be separated from the packaging bag. [Examples]

[0084] The present invention will be described in more detail below as examples, but it is not limited to these examples.

[0085] <Example 1> As a base layer, a 25 μm thick, uniaxially oriented, high-density polyethylene film with printing (stretch ratio 5x) was subjected to atmospheric pressure plasma treatment on the printed side under a nitrogen gas atmosphere. Next, molten linear low-density polyethylene was extruded between the base layer and a 90 μm thick linear low-density polyethylene film to form a 20 μm thick intermediate layer, and the layers were laminated by sandwich lamination. At this time, the intermediate layer, which was to be bonded to the base layer, was extruded while undergoing an ozone oxidation treatment on its surface. This resulted in the acquisition of laminate 1. The total film thickness of laminate 1 was 135 μm.

[0086] The proportion of polyethylene resin to the total amount of resin constituting laminate 1, calculated from the composition of the raw materials, was 99% by mass.

[0087] <Comparative Example 1> A 25 μm thick, uniaxially oriented, high-density polyethylene film with printing (stretch ratio 5x) was used as the base layer, and a two-component curing polyurethane adhesive was applied to form an intermediate layer. A linear low-density polyethylene film with a thickness of 110 μm was laminated by dry lamination to the side of the intermediate layer opposite to the side in contact with the substrate layer. This resulted in laminate 2. The total film thickness of laminate 2 was 135 μm.

[0088] The proportion of polyethylene resin to the total amount of resin constituting laminate 2, calculated from the composition of the raw materials, was 95% by mass.

[0089] <Measurement of tensile strength of laminated materials> The tensile strength of laminate 1 and laminate 2 was measured using the method described in the [Tensile Strength Test] above. As a result, the tensile strength of laminate 1 was 96.1 N / 10 mm, and the tensile strength of laminate 2 was 90.2 N / 10 mm.

[0090] <Drop test> Using laminate 1 or laminate 2, packaging bags were manufactured using the method described in [Drop Test] above, and a drop test was conducted.

[0091] The drop test results showed that when the packaging using laminate 1 was dropped from 1m, 0 out of 100 packaging bags were torn, and when dropped from 1.2m, 6 out of 60 packaging bags were torn. When the packaging using laminated material 2 was dropped from 1 meter, 6 out of 100 packaging bags were torn, and when dropped from 1.2 meters, 22 out of 50 packaging bags were torn.

[0092] As shown in the results above, it was confirmed that the packaging bag manufactured using the laminate 1 to which the present invention is applied is less likely to tear when filled with contents and dropped, thus possessing drop resistance. [Explanation of Symbols]

[0093] 1: Container body, 2: Spout component, 5: Cap, 7: Dispensing cylinder, 10: Packaging bag, 10a: Storage section, 11a: Side edge seal section, 12: Bottom film, 12a: Bottom seal section, 51: Body film, 20: Laminate, 21: Base layer, 22: Intermediate layer, 23: Sealant layer

Claims

1. A laminate formed from polyolefin resin, The laminate comprises, at least, a base layer formed from stretched polyethylene film, an intermediate layer formed from extruded polyolefin resin, and a sealant layer, all laminated in this order. A printing layer is provided on the surface of the substrate layer facing the intermediate layer, The substrate layer and the printing layer are arranged directly adjacent to each other in the thickness direction of the laminate. The printed layer and the intermediate layer are arranged directly adjacent to each other in the thickness direction of the laminate. A laminate in which the intermediate layer and the sealant layer are arranged directly adjacent to each other in the thickness direction of the laminate.

2. The laminate according to claim 1, wherein the base layer, the intermediate layer, and the sealant layer are formed from polyethylene resin.

3. The material used to form the base layer is an stretched medium-density polyethylene (MDPE) resin film or a stretched high-density polyethylene (HDPE) resin film. The intermediate layer forming material is linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), or a mixed resin of linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE). The laminate according to claim 2, wherein the material forming the sealant layer is linear low-density polyethylene (LLDPE) resin or low-density polyethylene (LDPE) resin.

4. A packaging bag using the laminate according to any one of claims 1 to 3.

5. A packaging bag according to claim 4, for packaging liquids.

6. The packaging bag according to claim 4 or 5, which is a standing pouch having a body film and a bottom film.

7. The packaging bag according to claim 6, which is a standing pouch in which the laminate according to any one of claims 1 to 3 is used only for the body film.

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