WO2023190903A1

WO2023190903A1 - Multilayer body and packaging bag

Info

Publication number: WO2023190903A1
Application number: PCT/JP2023/013257
Authority: WO
Inventors: 峻石川; 真一朗河野; 祐也高杉; 清中田; 憲一山田
Original assignee: 大日本印刷株式会社
Priority date: 2022-03-30
Filing date: 2023-03-30
Publication date: 2023-10-05

Abstract

The present invention provides a multilayer body which comprises at least a stretched base material and a sealant layer, wherein: the stretched base material comprises at least a polyolefin layer; the sealant layer contains a polyolefin as a main component; the multilayer body comprises a heat-generating resin layer that contains, as a main component, a heteroatom-containing resin which generates heat upon absorption of laser radiation; and the heat-generating resin layer is positioned at least between the stretched base material and the sealant layer or on a surface of the stretched base material, the surface being on the reverse side of the sealant layer-side surface, in the stretched base material.

Description

Laminates and packaging bags

Cross-reference of related applications

This application claims priority based on Japanese Patent Application No. 2022-57556 filed on March 30, 2022 and Japanese Patent Application No. 2022-57547 filed on March 30, 2022. , the entire disclosures of which are hereby incorporated by reference.

The present disclosure relates to a laminate and a packaging bag.

Packaging bags are used to store fluid contents such as liquids and powders. The packaging bag is composed of a laminate including a base material and a sealant layer. For example, a resin film made of polyolefin such as polyethylene is widely used as a sealant layer because it has flexibility and transparency and has excellent heat sealability. Furthermore, resin films made of polyester or polyamide are widely used as base materials because of their excellent strength and heat resistance.

In recent years, there has been a demand for recycling packaging bags from the perspective of reducing environmental impact. From the viewpoint of recycling, it is preferable that the base material and the sealant layer are each made of the same type of resin material (monomaterialization). For example, Patent Document 1 proposes that the base material and the sealant layer are made of polyethylene.

JP2020-55156A

From the perspective of making it easier to open the packaging bag by hand, easy-to-open lines are sometimes formed on the packaging bag. The present inventors have considered forming an easy-to-open line by irradiating a laminate with a laser to form an altered portion. It is thought that the laminate can be easily torn along the altered portion (easy tear line).

If the base material contains a different type of resin material from the resin material that makes up the sealant layer, by selecting a laser that is absorbed by the base material but not absorbed by the sealant layer, the base material can be selectively exposed to altered parts. can be formed. However, from the viewpoint of recycling, when the base material and the sealant layer are each made of the same type of resin material, polyolefin such as polyethylene, the base material cannot absorb the laser sufficiently, and the deteriorated parts of the base material are not easily formed. They tend not to form. Therefore, the tearability was not sufficiently improved by laser irradiation.

One object of the present disclosure is to provide a laminate that has excellent recyclability and can improve tearability by laser irradiation.

The laminate of the first aspect of the present disclosure includes at least a stretched base material and a sealant layer, the stretched base material includes at least a polyolefin layer, the sealant layer contains polyolefin as a main component, and the laminate includes: A heat-generating resin layer containing as a main component a heteroatom-containing resin that absorbs laser and generates heat, and the heat-generating resin layer is arranged in the stretched base material, between the stretched base material and the sealant layer, and in the stretched base material. located at at least one location on the surface opposite to the surface on the sealant layer side.

The laminate of the second aspect of the present disclosure includes at least a stretched base material and a sealant layer, the stretched base material contains polyethylene as a main component, and the sealant layer includes a first layer, a second layer, and a sealant layer. The first layer contains an ethylene/α-olefin copolymer as a main component, the first layer has a melting point of 112° C. or lower, and the second layer contains a polyethylene as a main component. the melting point of the second layer is 114° C. or higher, one surface layer of the laminate is the first layer, and the laminate has a laser beam between the stretched base material and the sealant layer. The apparatus further includes a heat generating layer containing a heat generating substance that absorbs and generates heat.

According to the present disclosure, it is possible to provide a laminate that has excellent recyclability and can favorably improve tearability by laser irradiation. By using the laminate of the present disclosure, a packaging bag with excellent recyclability and ease of opening can be produced.

FIG. 1 is a schematic cross-sectional view showing one embodiment of a laminate. FIG. 2 is a schematic cross-sectional view showing one embodiment of the laminate. FIG. 3 is a schematic cross-sectional view showing one embodiment of the laminate. FIG. 4 is a schematic cross-sectional view showing one embodiment of the laminate. FIG. 5 is a front view showing one embodiment of the packaging bag. FIG. 6 is a cross-sectional view showing an example of a through hole of an easy-to-open wire. FIG. 7 is a diagram for explaining a method of measuring the width of the altered part. FIG. 8 is a front view showing an example of an easy-to-open line. FIG. 9 is a front view showing one embodiment of the packaging bag. FIG. 10 is a front view showing one embodiment of the packaging bag. FIG. 11 is a front view showing one embodiment of a packaging bag. FIG. 12 is a front view of a test piece for measuring tear strength. FIG. 13 is an observation image of the cross-sectional shape of the laminate. FIG. 14 is an observation image of the cross-sectional shape of the laminate. FIG. 15 is a schematic cross-sectional view showing one embodiment of the laminate. FIG. 16 is a schematic cross-sectional view showing one embodiment of the sealant layer. FIG. 17 is a schematic cross-sectional view showing one embodiment of the sealant layer. FIG. 18 is a schematic cross-sectional view showing one embodiment of the sealant layer.

Hereinafter, embodiments of the present disclosure will be described in detail. This disclosure may be implemented in many different forms and is not to be construed as limited to the description of the exemplary embodiments below. In order to make the explanation clearer, the drawings may schematically represent the width, thickness, shape, etc. of each layer compared to the embodiment, but this is just an example and does not limit the interpretation of the present disclosure. . In this specification and each figure, elements that are the same as those already explained with respect to the existing figures are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

In this specification, when multiple upper limit value candidates and multiple lower limit value candidates are listed for a certain parameter, the numerical range of the parameter is defined as any one upper limit value candidate and any one lower limit value. It may be configured by combining the candidates. As an example, "Parameter B is preferably A1 or more, more preferably A2 or more, even more preferably A3 or more. Parameter B is preferably A4 or less, more preferably A5 or less, and still more preferably A6 or less." '' will be explained. In this example, the numerical range of parameter B may be A1 or more and A4 or less, A1 or more and A5 or less, A1 or more and A6 or less, A2 or more and A4 or less, A2 or more and A5 or less, A2 or more and A6 or less. It may be A3 or more and A4 or less, A3 or more and A5 or less, or A3 or more and A6 or less.

In the following description, each component that appears (for example, polyolefins such as polyethylene and polypropylene, α-olefins, resin materials such as heteroatom-containing resins and adhesive resins, additives, and exothermic substances) may be used alone. Often, two or more types may be used.
In the following description, when referring to the laminate with respect to matters common between the laminate of the first aspect and the laminate of the second aspect, it is also simply referred to as a "laminate."
"Main component" means a component contained in a layer or base material in an amount of 50% by mass or more.

[Laminated body]
The laminate of the present disclosure includes at least a stretched base material and a sealant layer.
The laminate of the present disclosure can be suitably used as a packaging material.

In the laminate of the first aspect, the stretched base material includes at least a polyolefin layer. In the laminate of the first embodiment, the sealant layer contains polyolefin as a main component.
The laminate of the first aspect of the present disclosure includes a heat-generating resin layer containing as a main component a heteroatom-containing resin that generates heat by absorbing laser. In the laminate of the first aspect of the present disclosure, the exothermic resin layer is provided in the stretched base material, between the stretched base material and the sealant layer, and on the surface of the stretched base material opposite to the surface on the sealant layer side. located in at least one of the following locations: With such a configuration, for example, the laminate can be irradiated with a laser to form a deteriorated portion, and the laminate can be easily torn by hand, thereby improving the ease of opening a packaging bag including the laminate. For example, by forming altered parts along the longitudinal direction (MD), transverse direction (direction perpendicular to MD, TD) of the laminate, or in a direction diagonal to MD at 45 degrees, tearing in each direction can be achieved. You can improve your sexuality. In particular, it is possible to improve not only the MD and TD of the laminate, but also the tearability in a direction diagonal to the MD at 45 degrees.

In one embodiment, the main components of the resin constituting the stretched base material and the resin constituting the sealant layer are both polyolefins, so that, for example, the recyclability of the laminate can be improved.

The content of polyolefin (specifically polyethylene or polypropylene) in the entire laminate of the first aspect of the present disclosure is preferably 80% by mass or more, more preferably 85% by mass or more, and still more preferably 90% by mass or more. be. Thereby, for example, a monomaterial packaging bag can be produced using the laminate, and the recyclability of the packaging bag can be improved. The upper limit of the polyolefin content is not particularly limited, but may be 99% by mass or 95% by mass.

In the laminate of the second aspect, the stretched base material contains polyethylene as a main component. In the laminate of the second aspect, the sealant layer includes at least a first layer and a second layer, each of which will be described later.
The laminate of the second aspect of the present disclosure further includes a heat generating layer containing a heat generating substance that absorbs laser and generates heat between the stretched base material and the sealant layer. With such a configuration, for example, the laminate can be irradiated with a laser to form a deteriorated portion, and the laminate can be easily torn by hand, thereby improving the ease of opening a packaging bag including the laminate. For example, by forming altered parts along the longitudinal direction (MD), transverse direction (direction perpendicular to MD, TD) of the laminate, or in a direction diagonal to MD at 45 degrees, tearing in each direction can be achieved. You can improve your sexuality. In particular, it is possible to improve not only the MD and TD of the laminate, but also the tearability in a direction diagonal to the MD at 45 degrees.

In one embodiment, the main components of the resin constituting the stretched base material and the resin constituting the sealant layer are both polyethylene, so that, for example, the recyclability of the laminate can be improved.

The content of polyethylene in the entire laminate of the second aspect of the present disclosure is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. Thereby, for example, a monomaterial packaging bag can be produced using the laminate, and the recyclability of the packaging bag can be improved. The upper limit of the content of polyethylene is not particularly limited, but may be 99% by mass or 95% by mass.

<Stretched base material>
In the laminate of the first aspect, the stretched base material includes at least a polyolefin layer. In the present disclosure, the term "polyolefin layer" refers to a layer containing polyolefin such as polyethylene and polypropylene as a main component.

The stretched base material may be a polyolefin base material containing polyolefin as a main component. In the laminate of the second aspect, the stretched base material is a polyethylene base material containing polyethylene as a main component.

The stretched base material may contain additives. Examples of additives include crosslinking agents, antioxidants, antiblocking agents, slip agents, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, compatibilizers, pigments, and modifying resins. Can be mentioned.

The stretched base material may further include a heat-generating resin layer containing as a main component a heteroatom-containing resin that absorbs laser and generates heat. That is, the stretched base material may include a polyolefin layer and a heat-generating resin layer. The stretched base material may include, for example, a polyolefin layer, an adhesive resin layer, a heat-generating resin layer, an adhesive resin layer, and a polyolefin layer in this order, and the polyolefin layer, the adhesive resin layer, The heat generating resin layer may be provided in this order. Each layer such as a polyolefin layer may be present in two or more layers.

The stretched base material is a base material that has been subjected to a stretching process. Thereby, for example, the strength, heat resistance, and transparency of the base material can be improved. The stretching treatment may be uniaxial stretching or biaxial stretching. The stretching ratio when stretching in the longitudinal direction (the flow direction of the base material, MD) may be 2 times or more, 3 times or more, 10 times or less, or 7 times or less. The stretching ratio when stretching in the transverse direction (direction perpendicular to MD, TD) may be 2 times or more, 3 times or more, 10 times or less, or 7 times or less. The stretched base material is, for example, a uniaxially stretched film stretched in the machine direction (MD).

The stretched base material may have a single layer structure or a multilayer structure.
The thickness of the stretched base material is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, and preferably 200 μm or less, more preferably 100 μm or less, and still more preferably 50 μm or less, for example, 5 μm or more and 200 μm or less. It is as follows. When the thickness is at least the lower limit, for example, the strength and heat resistance of the laminate can be improved. When the thickness is below the upper limit, for example, the processability of the laminate can be improved.

The stretched base material can be produced, for example, by forming a film from a polyolefin such as polyethylene or its resin composition by an inflation molding method, a T-die molding method, or the like, and then stretching the film. According to the inflation molding method, film formation and stretching can be performed simultaneously.

The stretched substrate, in one embodiment, is a coextruded resin film.
In one embodiment, the stretched base material is a resin film obtained by coextruding two or more materials constituting a polyolefin layer such as a polyethylene layer using a coextrusion inflation method and further stretching the film.
In one embodiment, the stretched base material includes a material constituting the polyolefin layer, a material constituting the adhesive resin layer when the stretched base material includes an adhesive resin layer, and a material constituting the exothermic resin layer. , a resin film obtained by coextrusion film formation by a coextrusion inflation method and further stretching treatment.

The stretched base material may be surface-treated. Thereby, for example, the adhesion between the stretched base material and other layers can be improved. Examples of surface treatment methods include physical treatments such as corona treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and/or nitrogen gas, and glow discharge treatment; and chemical treatments such as oxidation treatment using chemicals. For example,

(Polyolefin layer)
The polyolefin layer contains polyolefin as a main component. Examples of polyolefins include polyethylene, polypropylene, and polymethylpentene. As the polyolefin layer, a polyethylene layer and a polypropylene layer are preferred.

The melt flow rate (MFR) of the polyolefin is preferably 0.1 g/10 minutes or more, more preferably 0.2 g/10 minutes or more, and even more preferably 0.5 g/10 minutes from the viewpoint of film formability and processing suitability. or more, preferably 50 g/10 minutes or less, more preferably 30 g/10 minutes or less, even more preferably 10 g/10 minutes or less, particularly preferably 5.0 g/10 minutes or less, for example 0.1 g/10 minutes. It is more than 50g/10 minutes. The MFR of polyolefin is measured by method A under a load of 2.16 kg in accordance with JIS K7210-1:2014. The measurement temperature for MFR is set depending on the melting point of the polyolefin, and is, for example, 190°C in the case of polyethylene and 230°C in the case of polypropylene.

The content of polyolefin in the polyolefin layer is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, particularly preferably 90% by mass or more or 95% by mass or more.

The polyolefin layer may contain resin materials other than polyolefin. Examples of such resin materials include (meth)acrylic resins, vinyl resins, cellulose resins, polyamides, polyesters, and ionomer resins.

The polyolefin layer may contain additives. Examples of additives include crosslinking agents, antioxidants, antiblocking agents, slip agents, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, compatibilizers, pigments, and modifying resins. Can be mentioned.

The thickness of the polyolefin layer is preferably 5 μm or more, more preferably 10 μm or more, and preferably 100 μm or less, more preferably 50 μm or less, for example, 5 μm or more and 100 μm or less. When the thickness is at least the lower limit, the strength, heat resistance, and recyclability of the base material can be improved, for example. When the thickness is below the upper limit, for example, the processing suitability of the base material can be improved. When the stretched base material includes two or more polyolefin layers, the above "thickness" means the total thickness of each polyolefin layer.

The stretched base material may be provided with one polyolefin layer, or may be provided with two or more layers.

((Polyethylene layer))
The polyethylene layer contains polyethylene as a main component.
In the present disclosure, polyethylene refers to a polymer in which the content of ethylene-derived structural units is 50 mol% or more among all repeating structural units. In this polymer, the content of the structural unit derived from ethylene is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, particularly preferably 95 mol% or more. The above content ratio is measured by NMR method.

In the present disclosure, polyethylene may be a homopolymer of ethylene or a copolymer of ethylene and an ethylenically unsaturated monomer other than ethylene. Examples of ethylenically unsaturated monomers other than ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene. , 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene, and other α-olefins having 2 to 20 carbon atoms; vinyl such as vinyl acetate and vinyl propionate. Monomers; and (meth)acrylic esters such as methyl (meth)acrylate and ethyl (meth)acrylate.

In the present disclosure, polyethylene includes, for example, high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene. From the viewpoint of the strength and heat resistance of the stretched base material, high-density polyethylene and medium-density polyethylene are preferred. From the viewpoint of film formability and processability of the stretched base material, linear low-density polyethylene and medium-density polyethylene are preferred. Particularly preferred is medium density polyethylene. As the polyethylene, from the viewpoint of reducing environmental load, biomass-derived polyethylene, mechanically recycled or chemically recycled polyethylene may be used.

In the present disclosure, the density of polyethylene is as follows.
The density of the high density polyethylene is preferably greater than 0.945 g/cm ³ . The upper limit of the density of high-density polyethylene is, for example, 0.965 g/cm ³ . The density of the medium density polyethylene is preferably greater than 0.930 g/cm ³ and less than 0.945 g/cm ³ . The density of the low density polyethylene is preferably greater than 0.900 g/cm ³ and less than 0.930 g/cm ³ . The density of the linear low density polyethylene is preferably more than 0.900 g/cm ³ and less than 0.930 g/cm ³ . The density of the ultra-low density polyethylene is preferably 0.900 g/cm ³ or less. The lower limit of the density of ultra-low density polyethylene is, for example, 0.860 g/cm ³ . The density of polyethylene is measured according to method D (density gradient tube method, 23° C.) of JIS K7112:1999.

Low-density polyethylene is usually polyethylene obtained by polymerizing ethylene using a high-pressure polymerization method (high-pressure low-density polyethylene). Linear low-density polyethylene is usually polyethylene obtained by polymerizing ethylene and a small amount of α-olefin by a polymerization method using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst.

Polyethylenes having different densities or branches can be obtained by appropriately selecting the polymerization method. For example, a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst is used as a polymerization catalyst, and one-stage polymerization is performed by any one of gas phase polymerization, slurry polymerization, solution polymerization, and high-pressure ionic polymerization. Alternatively, it is preferable to carry out the polymerization in multiple stages of two or more stages.
The above description of polyethylene can also be applied elsewhere.

From the viewpoint of heat resistance, the melting point (Tm) of polyethylene is preferably 100°C or higher, more preferably 105°C or higher, even more preferably 110°C or higher, particularly preferably 120°C or higher, and preferably 140°C or lower. , for example, 100°C or more and 140°C or less. Tm is the melting peak temperature obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012.

The content of polyethylene in the polyethylene layer is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, particularly preferably 90% by mass or more or 95% by mass or more.

((Polypropylene layer))
The polypropylene layer contains polypropylene as a main component. By providing the stretched base material with a polypropylene layer, for example, the oil resistance of a packaging bag produced using the stretched base material can be improved.

The polypropylene may be any of a propylene homopolymer (homopolypropylene), a propylene random copolymer (random polypropylene), and a propylene block copolymer (block polypropylene), or a mixture of two or more selected from these. As the polypropylene, from the viewpoint of reducing environmental load, biomass-derived polypropylene, mechanically recycled or chemically recycled polypropylene may be used.

A propylene homopolymer is a polymer made only of propylene. A propylene random copolymer is a random copolymer of propylene and an α-olefin other than propylene. A propylene block copolymer is a copolymer having at least a polymer block made of propylene and a polymer block made of at least an α-olefin other than propylene.

Examples of α-olefins other than propylene include α-olefins having 2 to 20 carbon atoms, specifically ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1- Mention may be made of decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene and 6-methyl-1-heptene.

Among polypropylenes, propylene random copolymers are preferred from the viewpoint of transparency. When the rigidity and heat resistance of the packaging bag are important, propylene homopolymer is preferred. If the impact resistance of the packaging bag is important, propylene block copolymers are preferred.

The density of polypropylene is, for example, 0.88 g/cm ³ or more and 0.92 g/cm ³ or less. The density of polypropylene is measured according to method D (density gradient tube method, 23° C.) of JIS K7112:1999.

From the viewpoint of heat resistance, the melting point (Tm) of polypropylene is preferably 120°C or higher, more preferably 130°C or higher, even more preferably 150°C or higher, and preferably 170°C or lower, for example 120°C or higher and 170°C. It is as follows. Tm is the melting peak temperature obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012.

The content of polypropylene in the polypropylene layer is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, particularly preferably 90% by mass or more or 95% by mass or more.

(Exothermic resin layer)
The stretched base material may further include a heat-generating resin layer containing as a main component a heteroatom-containing resin that absorbs laser and generates heat. Thereby, for example, by irradiating the laminate with a laser, an easy-to-open line including the altered portion can be formed, and the unsealability of the packaging bag can be improved.

Examples of the heteroatoms in the heteroatom-containing resin include oxygen atoms, sulfur atoms, and nitrogen atoms. The heteroatom-containing resin has a heteroatom-containing group such as a hydroxy group, an amide group, an ester group, and an imide group. Examples of the heteroatom-containing resin that absorbs laser and generates heat include ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyamide, polyester, and polyimide. Among these, from the viewpoint of ease of opening the packaging bag, ethylene-vinyl alcohol copolymers, polyvinyl alcohol and polyamides are preferred, ethylene-vinyl alcohol copolymers and polyamides are more preferred, and ethylene-vinyl alcohol copolymers are even more preferred. preferable.

Ethylene-vinyl alcohol copolymer (EVOH) can be obtained, for example, by copolymerizing ethylene and a vinyl ester monomer and then saponifying the copolymer. The copolymerization of ethylene and the vinyl ester monomer can be carried out by any known polymerization method, such as solution polymerization, suspension polymerization, emulsion polymerization, etc.

As the vinyl ester monomer, vinyl acetate is generally used, but other vinyl ester monomers may also be used. Examples of other vinyl ester monomers include vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, and vinyl versatate. Aliphatic vinyl esters include aromatic vinyl esters such as vinyl benzoate.

The content ratio of structural units derived from ethylene (ethylene content ratio) in EVOH is preferably 20 mol% or more, more preferably 25 mol% or more, and preferably 60 mol% or less, more preferably 50 mol% or less. For example, it is 20 mol% or more and 60 mol% or less. When the ethylene content is at least the lower limit, for example, the processing suitability of the stretched base material can be improved. When the ethylene content is at most the upper limit, for example, the unsealability of the packaging bag can be improved, and the oxygen barrier properties and water vapor barrier properties of the stretched base material can be improved. The ethylene content rate is measured by NMR method.

The average degree of saponification in EVOH may be 90 mol% or more, 95 mol% or more, or 99 mol% or more. The average saponification degree is measured in accordance with JIS K6726:1994 (however, EVOH uses a solution uniformly dissolved in a water/methanol solvent).

From the viewpoint of heat resistance, the melting point (Tm) of EVOH is preferably 140°C or higher, more preferably 145°C or higher, even more preferably 150°C or higher, and preferably 200°C or lower, more preferably 195°C or lower, and Preferably it is 190°C or less, for example 140°C or more and 200°C or less. The Tm of EVOH is the melting peak temperature obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012.

The melt flow rate (MFR) of EVOH is preferably 0.1 g/10 minutes or more, more preferably 0.3 g/10 minutes or more, and even more preferably 0.5 g/10 minutes from the viewpoint of film formability and processing suitability. or more, preferably 30 g/10 minutes or less, more preferably 20 g/10 minutes or less, even more preferably 10 g/10 minutes or less, particularly preferably 5.0 g/10 minutes, for example 0.1 g/10 minutes. It is 30g/10 minutes or less. The MFR of EVOH is measured in accordance with ASTM D1238 at a temperature of 190° C. and a load of 2.16 kg. The measurement temperature may be 210° C. depending on the melting point of EVOH.

EVOH may be modified by urethanation, acetalization, cyanoethylation, oxyalkylenation, etc. by known methods.

The average degree of saponification in polyvinyl alcohol (PVA) may be 70 mol% or more, 75 mol% or more, 80 mol% or more, or 85 mol% or more. The average degree of saponification is measured in accordance with JIS K6726:1994.

Examples of the polyamide include aliphatic polyamide and semi-aromatic polyamide. As the polyamide, aliphatic polyamide is preferable, and crystalline aliphatic polyamide is more preferable.

Examples of aliphatic polyamides include aliphatic homopolyamides and aliphatic copolyamides. In the following examples, polyamide is also referred to as "PA".

Specifically, the aliphatic homopolyamides include polycaprolactam (PA6), polyenanthlactam (PA7), polyundecanelactam (PA11), polylauryllactam (PA12), polyhexamethylene adipamide (PA66), and polyamide. Tetramethylene dodecamide (PA412), polypentamethylene azelamide (PA59), polypentamethylene sebacamide (PA510), polypentamethylene dodecamide (PA512), polyhexamethylene azeramide (PA69), polyhexamethylene sebaca Mido (PA610), polyhexamethylene dodecamide (PA612), polynonamethylene adipamide (PA96), polynonamethylene azeramide (PA99), polynonamethylene sebacamide (PA910), polynonamethylene dodecamide (PA912) ), polydecamethylene adipamide (PA106), polydecamethylene azeramide (PA109), polydecamethylene decamide (PA1010), polydecamethylene dodecamide (PA1012), polydodecamethylene adipamide (PA126), poly Mention may be made of dodecamethylene azeramide (PA129), polydodecamethylene sebacamide (PA1210) and polydodecamethylene dodecamide (PA1212).

Specifically, the aliphatic copolymer polyamides include caprolactam/hexamethylene diamino adipic acid copolymer (PA6/66), caprolactam/hexamethylene diamino azelaic acid copolymer (PA6/69), and caprolactam/hexamethylene diamino acid copolymer (PA6/69). Sebacic acid copolymer (PA6/610), caprolactam/hexamethylenediaminoundecanoic acid copolymer (PA6/611), caprolactam/hexamethylenediaminododecanoic acid copolymer (PA6/612), caprolactam/aminoundecanoic acid copolymer combination (PA6/11), caprolactam/lauryllactam copolymer (PA6/12), caprolactam/hexamethylene diamino adipic acid/lauryllactam copolymer (PA6/66/12), caprolactam/hexamethylene diamino adipic acid/hexa Examples include methylene diamino sebacic acid copolymer (PA6/66/610) and caprolactam/hexamethylene diamino adipic acid/hexamethylene diamino dodecane dicarboxylic acid copolymer (PA6/66/612).

The relative viscosity of the aliphatic polyamide is preferably 1.5 or more and 5.0 or less, more preferably 2.0 or more and 5.0 or less, and still more preferably 2.5 or more and 4.5 or less. The relative viscosity of aliphatic polyamide is measured at 25° C. by dissolving 1 g of polyamide in 100 mL of 96% concentrated sulfuric acid in accordance with JIS K6920-2:2009.

Semi-aromatic polyamide is a polyamide having a structural unit derived from an aromatic diamine and a structural unit derived from an aliphatic dicarboxylic acid, or a polyamide having a structural unit derived from an aliphatic diamine and a structural unit derived from an aromatic dicarboxylic acid. It is a polyamide having structural units. Examples include polyamides composed of aromatic diamines and aliphatic dicarboxylic acids, and polyamides composed of aliphatic diamines and aromatic dicarboxylic acids.

Examples of semi-aromatic polyamides include polyhexamethylene terephthalamide (PA6T), polyhexamethylene isophthalamide (PA6I), polynonamethylene terephthalamide (PA9T), and polyhexamethylene adipamide/polyhexamethylene terephthalamide copolymer. (PA66/6T), polyhexamethylene adipamide/polyhexamethylene isophthalamide copolymer (PA66/6I), polyhexamethylene terephthalamide/polycaproamide copolymer (PA6T/6), polyhexamethylene isophthalamide amide/polycaproamide copolymer (PA6I/6), polyhexamethylene terephthalamide/polydodecamide copolymer (PA6T/12), polyhexamethylene isophthalamide/polyhexamethylene terephthalamide copolymer (PA6I/6T), Polyhexamethylene terephthalamide/poly(2-methylpentamethylene terephthalamide) copolymer (PA6T/M5T), polyhexamethylene adipamide/polyhexamethylene terephthalamide/polyhexamethylene isophthalamide copolymer (PA66/6T) /6I), polyhexamethylene adipamide/polycaproamide/polyhexamethylene isophthalamide copolymer (PA66/6/6I), and polymethaxylylene adipamide (PAMXD6).

The melt volume rate (MVR) of the semi-aromatic polyamide is preferably from 5 cm ³ /10 minutes to 200 cm ³ /10 minutes, more preferably from 10 cm ³ /10 minutes to 100 cm ³ /10 minutes. MVR is measured at a temperature of 275° C. and a load of 5 kg in accordance with ISO1133.

As the polyamide, crystalline aliphatic polyamide is preferred. Examples of crystalline aliphatic polyamides include PA6, PA11, PA12, PA66, PA610, PA612, PA6/66 and PA6/66/12.

The melting point (Tm) of the crystalline aliphatic polyamide is preferably 180°C or higher, preferably 300°C or lower, more preferably 250°C or lower, even more preferably 230°C or lower, for example, 180°C or higher and 300°C or lower. be. Tm of polyamide is the melting peak temperature obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012.

The content ratio of the heteroatom-containing resin in the exothermic resin layer is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, particularly preferably 90% by mass or more, or 95% by mass or more. be. Thereby, for example, the ease of opening the packaging bag can be improved.

The exothermic resin layer may contain the above additives.

The thickness of the exothermic resin layer in the stretched base material is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 1.5 μm or more, and preferably 10 μm or less, more preferably 8.0 μm or less. , more preferably 6.0 μm or less, for example 0.5 μm or more and 10 μm or less. When the thickness is equal to or greater than the lower limit, for example, the ease of opening the packaging bag can be improved. When the thickness is below the upper limit, for example, the recyclability of the laminate can be improved. When the stretched base material includes two or more heat-generating resin layers, the above "thickness" means the total thickness of each heat-generating resin layer.

The thickness of the exothermic resin layer is preferably 1% or more, more preferably 3% or more, even more preferably 5% or more, and preferably 30% or less, more preferably It is 25% or less, more preferably 20% or less, for example 1% or more and 30% or less. When the stretched base material includes two or more heat-generating resin layers, the above "thickness" means the total thickness of each heat-generating resin layer.

(adhesive resin layer)
The stretched base material including the heat generating resin layer may include an adhesive resin layer between the polyolefin layer and the heat generating resin layer. Thereby, for example, the adhesion between the polyolefin layer and the exothermic resin layer can be improved.

The adhesive resin layer contains a resin material. Examples of the resin material include polyolefin, modified polyolefin, vinyl resin, polyether, polyester, polyurethane, silicone resin, epoxy resin, and phenol resin. Among these, from the viewpoint of recyclability and adhesion, polyolefins and modified polyolefins are preferred, and modified polyolefins such as acid-modified polyolefins are more preferred.

Examples of modified polyolefins include modified polyolefins, particularly graft-modified polyolefins, with unsaturated carboxylic acids such as maleic acid and fumaric acid, or acid anhydrides, esters, or metal salts thereof. Among the resin materials, modified polyolefins are preferred from the viewpoint of obtaining a structure suitable for monomaterial packaging materials.

The melt flow rate (MFR) of the modified polyolefin may be 0.1 g/10 minutes or more, 0.3 g/10 minutes or more, or 0.5 g/10 minutes or more from the viewpoint of film formability and processing suitability. , 50 g/10 minutes or less, 30 g/10 minutes or less, 10 g/10 minutes or less, for example, 0.1 g/10 minutes or more and 50 g/10 minutes or less. The MFR of the modified polyolefin is measured in accordance with ASTM D1238 at a temperature of 190° C. and a load of 2.16 kg, but the measurement temperature may be changed depending on the melting point of the modified polyolefin.

The adhesive resin layer may contain the above additives.

The thickness of the adhesive resin layer is preferably 0.5 μm or more, more preferably 1.0 μm or more, and preferably 15 μm or less, more preferably 10 μm or less, for example, 0.5 μm or more and 15 μm or less. For example, when the thickness is at least the lower limit, the adhesion can be improved. When the thickness is below the upper limit, for example, the recyclability of the laminate can be improved. When the stretched base material includes two or more adhesive resin layers, the above "thickness" means the total thickness of each adhesive resin layer.

Specifically, the stretched base material provided with a heat-generating resin layer includes (1) a stretched base material comprising a medium-density polyethylene layer, an adhesive resin layer, and a heat-generating resin layer in this order; (2) medium-density polyethylene layer; A stretched base material comprising a polyethylene layer, a medium-density polyethylene layer, a medium-density polyethylene layer, an adhesive resin layer, and a heat-generating resin layer in this order; (3) a medium-density polyethylene layer, an adhesive resin layer, An example is a stretched base material comprising a heat generating resin layer, an adhesive resin layer, and a medium density polyethylene layer in this order. Here, the medium density polyethylene layer contains medium density polyethylene as a main component. In the case of the stretched base materials (1) and (2), for example, the exothermic resin layer is arranged so as to face the sealant layer side.

<Polyolefin base material>
The stretched base material may be a polyolefin base material including a polyolefin layer and containing polyolefin as a main component. Examples of the polyolefin include polyethylene, polypropylene, and polymethylpentene, and the details are as described above. As the polyolefin base material, a polyethylene base material and a polypropylene base material are preferred.

The content of polyolefin in the polyolefin base material is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more. be.

The polyolefin base material may contain the above resin materials other than polyolefin.
The polyolefin base material may contain the above additives.

The haze value of the polyolefin base material may be 25% or less, 15% or less, or 10% or less. The lower limit of the haze value may be 0.1% or 1%. The haze value of the polyolefin base material is measured in accordance with JIS K7136:2000.

The polyolefin base material may have a single layer structure or a multilayer structure. A polyolefin base material having a multilayer structure is preferable from the viewpoint of, for example, an excellent balance of strength, heat resistance, printability, and stretching suitability. The polyolefin base material may have two or more polyolefin layers. In this case, the number of polyolefin layers may be 2 or more, 3 or more, 7 or less, or 5 or less, for example, 3, 5, or 7 layers.

The thickness of the polyolefin base material is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, and preferably 200 μm or less, more preferably 100 μm or less, and still more preferably 50 μm or less, for example, 5 μm or more and 200 μm or less. It is as follows. When the thickness is at least the lower limit, for example, the strength and heat resistance of the laminate can be improved. When the thickness is below the upper limit, for example, the processability of the laminate can be improved.

(Polyethylene base material)
The polyethylene base material contains polyethylene as a main component.
Details of the polyethylene are as described above.

The melt flow rate (MFR) of polyethylene is preferably 0.1 g/10 minutes or more, more preferably 0.2 g/10 minutes or more, and even more preferably 0.5 g/10 minutes from the viewpoint of film formability and processing suitability. or more, preferably 50 g/10 minutes or less, more preferably 30 g/10 minutes or less, even more preferably 10 g/10 minutes or less, particularly preferably 5.0 g/10 minutes or less, for example 0.1 g/10 minutes. It is more than 50g/10 minutes. The MFR of polyethylene is measured by method A under a load of 2.16 kg in accordance with JIS K7210-1:2014. The measurement temperature of MFR is 190°C.

The content of polyethylene in the polyethylene base material is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more. be. With such a configuration, for example, the recyclability of the laminate can be improved.

The polyethylene base material may be a uniaxially stretched film or a biaxially stretched film, for example, a uniaxially stretched film that has been stretched in the machine direction (MD). Details of the stretching process are as described above.

The polyethylene base material may have a single layer structure or a multilayer structure. The stretched base material may be provided with one polyethylene layer containing polyethylene as a main component, or may be provided with two or more layers. A polyethylene base material having a multilayer structure is preferable from the viewpoint of, for example, an excellent balance of strength, heat resistance, printability, and stretching suitability. In the case of a polyethylene base material having a multilayer structure, the number of polyethylene layers may be 2 or more, 3 or more, 7 or less, or 5 or less, for example, 3, 5, or 7. It is a layer.

Examples of polyethylene base materials having a multilayer structure include the following.
(1) A base material comprising a medium density polyethylene layer, a high density polyethylene layer, a blend layer of medium density polyethylene and high density polyethylene, a high density polyethylene layer, and a medium density polyethylene layer in this order;
(2) A base material comprising, in this order, a medium density polyethylene layer, a medium density polyethylene layer, a blend layer of medium density polyethylene and linear low density polyethylene, a medium density polyethylene layer, and a medium density polyethylene layer;
(3) A blend layer of medium density polyethylene and high density polyethylene, a blend layer of medium density polyethylene and linear low density polyethylene, a linear low density polyethylene layer, and a blend layer of medium density polyethylene and linear low density polyethylene. A base material comprising a blend layer and a blend layer of medium density polyethylene and high density polyethylene in this order;
(4) A blend layer of medium density polyethylene and high density polyethylene, a blend layer of medium density polyethylene and linear low density polyethylene, a blend layer of medium density polyethylene and linear low density polyethylene, a blend layer of medium density polyethylene and linear low density polyethylene, A base material comprising a blend layer of linear low-density polyethylene and a blend layer of medium-density polyethylene and high-density polyethylene in this order;
(5) A blend layer of high-density polyethylene and medium-density polyethylene, a medium-density polyethylene layer, a blend layer of linear low-density polyethylene and medium-density polyethylene, a medium-density polyethylene layer, and a layer of high-density polyethylene and medium-density polyethylene. a base material comprising a blend layer in this order;
(6) A blend layer of medium density polyethylene and high density polyethylene, a high density polyethylene containing layer, a linear low density polyethylene layer, a high density polyethylene layer, a blend layer of medium density polyethylene and high density polyethylene, Base materials provided in this order;
(7) A blend layer of medium-density polyethylene and high-density polyethylene, a blend layer of medium-density polyethylene and linear low-density polyethylene, a linear low-density polyethylene layer, a high-density polyethylene layer, a medium-density polyethylene and high-density polyethylene layer, a base material comprising, in this order, a blend layer of density polyethylene;
(8) High-density polyethylene layer, medium-density polyethylene layer, low-density polyethylene layer, linear low-density polyethylene layer or very low-density polyethylene layer, medium-density polyethylene layer, and high-density polyethylene layer in this order. A base material provided;
(9) A high-density polyethylene layer, a blend layer of high-density polyethylene and medium-density polyethylene, a low-density polyethylene layer, a linear low-density polyethylene layer, or a very low-density polyethylene layer, and a blend of high-density polyethylene and medium-density polyethylene. a base material comprising a layer and a high-density polyethylene layer in this order;
(10) A base material comprising a high-density polyethylene layer, a high-density polyethylene layer, a blend layer of medium-density polyethylene and high-density polyethylene, a high-density polyethylene layer, and high-density polyethylene in this order;
(11) A base material comprising a medium-density polyethylene layer, a high-density polyethylene layer, a linear low-density polyethylene layer, a high-density polyethylene layer, and a medium-density polyethylene layer in this order.

Each of the base materials (1) to (11) above has five layers. Each layer is described as a first layer to a fifth layer in order from the outside. The thickness of each of the first layer and the fifth layer may be 0.5 μm or more, 1 μm or more, 10 μm or less, 8 μm or less, 5 μm or less, for example, 0.5 μm or more and 10 μm or less. . The thickness of each of the second layer and the fourth layer may be 0.5 μm or more, 1 μm or more, 15 μm or less, 10 μm or less, 8 μm or less, for example, 0.5 μm or more and 15 μm or less. . The thickness of the third layer may be 1 μm or more, 2 μm or more, 5 μm or more, 50 μm or less, 40 μm or less, 30 μm or less, for example, 1 μm or more and 50 μm or less.

Examples of the polyethylene base material having a multilayer structure include the following.
(12) A base material comprising a high-density polyethylene layer and a medium-density polyethylene layer in this order;
(13) A base material comprising a high-density polyethylene layer, a medium-density polyethylene layer, and a high-density polyethylene layer in this order.

(Polypropylene base material)
The polypropylene base material contains polypropylene as a main component. By including the polypropylene base material in the laminate of the present disclosure, for example, the oil resistance of a packaging bag produced using the laminate can be improved.
Details of the polypropylene are as described above.

The content of polypropylene in the polypropylene base material is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more. be. With such a configuration, for example, the recyclability of the laminate can be improved.

The polypropylene base material may be a uniaxially stretched film or a biaxially stretched film, for example, a biaxially stretched film. Details of the stretching process are as described above.

<Exothermic resin layer>
The laminate of the first aspect of the present disclosure may include the heat generating resin layer between the stretched base material and the sealant layer. The laminate of the first aspect of the present disclosure may include the heat-generating resin layer on the surface of the stretched base material opposite to the surface on the sealant layer side.

The details of the exothermic resin layer are as described above, so the explanation in this section will be omitted. As the heteroatom-containing resin that absorbs laser and generates heat, ethylene-vinyl alcohol copolymer and polyvinyl alcohol are preferred.

The thickness of the exothermic resin layer is preferably 0.1 μm or more, more preferably 0.3 μm or more, even more preferably 0.5 μm or more, and may be 5.0 μm or less, or 3.0 μm or less, for example, .1 μm or more and 5.0 μm or less. When the thickness is equal to or greater than the lower limit, for example, the ease of opening the packaging bag can be improved. When the thickness is below the upper limit, for example, the recyclability of the laminate can be improved.

The exothermic resin layer provided on the surface of the stretched base material is formed, for example, by applying a coating liquid containing the above-mentioned heteroatom-containing resin that generates heat by absorbing laser to the stretched base material and drying it. be able to. That is, the exothermic resin layer may be a surface coat layer provided on the stretched base material. Furthermore, when the laminate is viewed in plan, the surface coat layer may be provided over the entire surface, or may be provided only at locations where easy-to-open lines are formed when a packaging bag is produced from the laminate.

<Anchor coat layer>
The laminate of the first aspect of the present disclosure may include a heat-generating resin layer on one surface or both surfaces of the stretched base material. The laminate of the first aspect of the present disclosure may include an anchor coat layer between the stretched base material and the heat-generating resin layer. The laminate of the present disclosure may include an anchor coat layer between the stretched base material and the heat generating layer. Thereby, for example, adhesion between layers can be improved.

Examples of the anchor coating agent include isocyanate-based, polyurethane-based, polyolefin-based, polyethyleneimine-based, or epoxy resin-based anchor coating agents. In one embodiment, the anchor coating agent is a two-component curable resin, and includes, for example, a polyol as a main ingredient and a polyisocyanate as a curing agent. In one embodiment, the anchor coating agent includes polyisocyanate. Examples of polyols include polyether polyols, polyester polyols, and (meth)acrylic polyols. Examples of the polyisocyanate include aromatic polyisocyanates such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, and polymethylene polyphenylene polyisocyanate, and aliphatic polyisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate. The anchor coat layer, in one embodiment, consists of polyurethane obtained by reaction of polyol and polyisocyanate. Specific examples of the polyurethane include polyether polyurethane, polyester polyurethane, and poly(meth)acrylic polyurethane.

The anchor coat layer can be formed, for example, by applying an anchor coat agent to the stretched base material. The anchor coating agent can be applied by, for example, a coating method such as a roll coating method, a gravure roll coating method, a kiss coating method, or a printing method.

The thickness of the anchor coat layer is preferably 0.05 μm or more, more preferably 0.1 μm or more, even more preferably 0.2 μm or more, and preferably 3.0 μm or less, more preferably 2.0 μm or less, and even more preferably is 1.0 μm or less, for example, 0.05 μm or more and 3.0 μm or less.

<Print layer>
The laminate of the first aspect of the present disclosure may include a printed layer. The laminate according to the second aspect of the present disclosure may include a printed layer other than the heat generating layer. The printing layer contains an image. Examples of images include characters, figures, patterns, symbols, and combinations thereof. The image may include text information such as the product name, the name of the contents in the packaging bag, the manufacturer, and the name of raw materials. The image may be a solid color (a so-called solid image).

The printing layer contains coloring materials such as pigments and dyes, for example. The printing layer may be formed using biomass-derived ink, for example. Thereby, for example, the environmental load can be further reduced. The heat generating layer described below may function as a printing layer containing an image.

Examples of methods for forming the printing layer include conventionally known printing methods such as gravure printing, offset printing, and flexographic printing. From the viewpoint of reducing environmental impact, a flexographic printing method may be used.

The thickness of the printing layer may be 0.5 μm or more, 1.0 μm or more, 10 μm or less, 6.0 μm or less, 4.0 μm or less, for example, 0.5 μm or more and 10 μm or less.

The printed layer may be formed on any surface of the stretched base material. The printed layer is preferably formed on the surface of the stretched base material on the sealant layer side, since contact between the printed layer and the outside air can be suppressed and deterioration of the printed layer over time can be suppressed.

<Heating layer>
The laminate of the first aspect of the present disclosure may further include a heat generating layer containing a heat generating substance that absorbs laser and generates heat (excluding the heteroatom-containing resin that absorbs laser and generates heat). . The laminate according to the second aspect of the present disclosure includes a heat generating layer containing a heat generating substance that absorbs laser and generates heat. Thereby, for example, by irradiating the laminate with a laser, an easy-to-open line including the altered portion can be formed, and the unsealability of the packaging bag can be improved. In one embodiment, the heat generating layer is provided between the stretched base material and the sealant layer. The heat generating layer may further contain a binder resin.

Examples of exothermic substances that absorb laser and generate heat include metal oxides, bismuth-based compounds, molybdenum or molybdenum-based compounds, copper or copper-based compounds, and carbon black. Among these, inorganic substances are preferred, and metal oxides are more preferred.

Examples of metal oxides include titanium oxide, magnesium oxide, zinc oxide, aluminum oxide, silicon oxide, nickel oxide, tin oxide, neodymium oxide, mica, zeolite, kaolinite, copper/molybdenum composite oxide, and copper/tungsten composite. Examples include oxides. Among these, titanium oxide is preferred. The heat generating layer may be, for example, a white layer or a white layer containing titanium oxide.

Examples of bismuth compounds include bismuth nitrates such as bismuth oxide, bismuth nitrate and bismuth oxynitrate, bismuth halides such as bismuth chloride, bismuth oxychloride, bismuth sulfate, bismuth acetate, bismuth citrate, bismuth hydroxide, Mention may be made of bismuth titanate and bismuth subcarbonate.

Examples of molybdenum-based compounds include molybdenum oxides such as molybdenum dioxide and molybdenum trioxide, molybdenum chloride, and metal molybdates. Examples of the metal component in the metal molybdate include K, Zn, Ca, Ni, bismuth, and Mg.

Examples of the copper-based compound include copper oxide, copper halide, organic acid copper such as formic acid, citric acid, salicylic acid, lauric acid, oxalic acid, and maleic acid, copper phosphate, and copper hydroxyphosphate.

The content ratio of the exothermic substance in the heat generating layer may be 5% by mass or more, 10% by mass or more, 20% by mass or more, 50% by mass or more, 85% by mass or less, 80% by mass or less. It may be 75% by mass or less, for example, 5% by mass or more and 85% by mass or less.

Examples of the binder resin include polyurethane, polyester, (meth)acrylic resin, and cellulose resin. The content ratio of the binder resin in the heat generating layer may be 15% by mass or more, 20% by mass or more, 25% by mass or more, 95% by mass or less, 90% by mass or less, or 80% by mass or less. It may be 50% by mass or less, for example, 15% by mass or more and 95% by mass or less.

The thickness of the heat generating layer may be 0.5 μm or more, 1.0 μm or more, 4.0 μm or less, 3.5 μm or less, or 3.0 μm or less, for example, 0.5 μm or more and 4.0 μm. The following may be used. When the thickness is equal to or greater than the lower limit, for example, the ease of opening the packaging bag can be improved. When the thickness is below the upper limit, for example, the recyclability of the laminate can be improved.

The position of the heat generating layer is, for example, between the stretched base material and the sealant layer. In addition, when the laminate is viewed in plan, the heat generating layer may be provided over the entire surface, or may be provided only at locations where easy-to-open lines are formed when producing a packaging bag from the laminate.

The heat generating layer can be formed, for example, by applying a composition containing a binder resin and a heat generating substance to a stretched base material and drying the composition. Examples of the coating method include printing methods such as gravure printing, offset printing, and flexographic printing. That is, the heat generating layer may be a printed layer provided on the stretched base material. Furthermore, when the laminate is viewed in plan, the printed layer may be provided on the entire surface, or may be provided only at the locations where easy-to-open lines are formed when producing a packaging bag from the laminate.

<Sealant layer>
The laminate of the present disclosure includes a sealant layer.
The sealant layer contains polyolefin such as polyethylene as a main component. This allows the packaging bag to be made of monomaterial. After collecting used packaging bags, there is no need to separate the stretched base material and the sealant layer, and the recyclability of the packaging bags can be improved.

Among polyolefins, polyethylene and polypropylene are preferred.

In one embodiment, the sealant layer contains polyethylene as a main component. Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene. and very low density polyethylene are preferred. As the polyethylene, from the viewpoint of reducing environmental load, biomass-derived polyethylene, mechanically recycled or chemically recycled polyethylene may be used.

From the viewpoint of heat-sealability, the sealant layer preferably contains low-density polyethylene and linear low-density polyethylene. From the viewpoint of tearability, the sealant layer preferably contains low density polyethylene. When the sealant layer contains low-density polyethylene and linear low-density polyethylene, the content ratio (mass %) of the linear low-density polyethylene may be larger than the content ratio (mass %) of the low-density polyethylene.

The melting point (Tm) of the polyethylene constituting the sealant layer is preferably 90°C or higher, more preferably 95°C or higher, and preferably 140°C or lower, more preferably 130°C or higher, from the viewpoint of the balance between heat resistance and heat sealability. ℃ or less, for example, 90°C or more and 140°C or less.

The MFR of the polyethylene constituting the sealant layer is preferably 0.1 g/10 minutes or more, more preferably 0.3 g/10 minutes or more, and even more preferably 0.5 g/10 minutes, from the viewpoint of film formability and processing suitability. or more, preferably 50 g/10 minutes or less, more preferably 30 g/10 minutes or less, still more preferably 10 g/10 minutes or less, for example 0.1 g/10 minutes or more and 50 g/10 minutes or less. For example, when the MFR is at least the lower limit, the processability of the sealant layer can be improved. For example, film formability can be improved if the MFR is below the upper limit.

The content of polyethylene in the sealant layer is preferably 50% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more. Thereby, for example, the recyclability of the packaging bag can be improved.

In one embodiment, the sealant layer contains polypropylene as a main component. Thereby, for example, the oil resistance of the packaging bag can be improved.

Examples of polypropylene include propylene homopolymers, propylene random copolymers such as propylene-α-olefin random copolymers, and propylene block copolymers such as propylene-α-olefin block copolymers. Details of the α-olefin are as described above. As the polypropylene, from the viewpoint of reducing environmental load, biomass-derived polypropylene, mechanically recycled or chemically recycled polypropylene may be used.

From the viewpoint of heat sealability, the density of polypropylene is, for example, 0.88 g/cm ³ or more and 0.92 g/cm ³ or less.

The melting point (Tm) of the polypropylene constituting the sealant layer is preferably 120°C or higher, more preferably 125°C or higher, even more preferably 130°C or higher, and preferably 160°C or higher, from the viewpoint of the balance between heat resistance and heat sealability. ℃ or less, more preferably 155°C or less, still more preferably 150°C or less, for example, 120°C or more and 160°C or less.

The content of polypropylene in the sealant layer is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more. Thereby, for example, the recyclability of the packaging bag can be improved.

The MFR of the polyolefin constituting the sealant layer is preferably 0.1 g/10 minutes or more, more preferably 0.3 g/10 minutes or more, and even more preferably 0.5 g/10 minutes, from the viewpoint of film formability and processing suitability. or more, preferably 50 g/10 minutes or less, more preferably 30 g/10 minutes or less, still more preferably 10 g/10 minutes or less, for example 0.1 g/10 minutes or more and 50 g/10 minutes or less. For example, when the MFR is at least the lower limit, the processability of the sealant layer can be improved. For example, film formability can be improved if the MFR is below the upper limit.

The content of polyolefin in the sealant layer is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 75% by mass or more. Thereby, for example, the recyclability of the packaging bag can be improved.

The sealant layer may contain the above additives.

The thickness of the sealant layer is preferably 10 μm or more, more preferably 30 μm or more, even more preferably 50 μm or more, particularly preferably 80 μm or more, and preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less. , for example, 10 μm or more and 300 μm or less. When the sealant layer has a multilayer structure, the total thickness thereof is preferably within the above range. When the thickness is at least the lower limit, for example, the heat sealability of the sealant layer and the recyclability of the packaging bag can be improved. When the thickness is below the upper limit, for example, the processability of the laminate can be improved.

From the viewpoint of heat sealability, the sealant layer is preferably an unstretched resin film, more preferably an unstretched coextruded resin film, and each layer constituting the sealant layer is a coextruded resin layer. The resin film can be produced by, for example, a casting method, a T-die method, an inflation method, or the like. "Unstretched" is a concept that includes not only a film that has not been stretched at all, but also a film that has been slightly stretched due to the tension applied during film formation.

For example, an unstretched resin film corresponding to the sealant layer may be laminated on the stretched base material via an adhesive layer as necessary, or a polyolefin such as polyethylene or its resin composition may be melt-extruded onto the stretched base material. A sealant layer may be formed by doing so. In the latter case, the adhesive layer may not be provided. Examples of the adhesive layer include the adhesive layer described below.

<Embodiment of sealant layer>
The sealant layer may include a first layer and a second layer as described below. The first layer contains an ethylene/α-olefin copolymer as a main component and has a melting point of 112° C. or lower. The second layer contains polyethylene as a main component and has a melting point of 114° C. or higher. The first layer can improve low-temperature sealing properties, and the second layer can improve rigidity and hand-cutting properties.

The stretched base material, which mainly contains polyethylene, is composed of polyethylene that has a lower melting point than conventional resin films such as polyester and nylon, so the heat sealing temperature when manufacturing packaging bags using the laminate is lower. cannot be made too high. In the case of a sealant layer comprising a first layer and a second layer, the first layer can be heat-sealed at a lower temperature than the second layer. Also, the sealing properties of the packaging bag can be maintained.

Stretched base material made of polyethylene has higher tear strength than resin films such as polyester or nylon, so when the laminate is processed into a packaging bag, the tearability (tearability) when opening the bag may be reduced. . By combining the stretched base material and the sealant layer of the above embodiment, the tearability of the laminate is improved. Although the reason for this is not clear, it can be assumed that the sealant layer, which includes the second layer having a melting point of 114° C. or higher, improves the toughness and further improves the tearability of the laminate. In addition, in the present disclosure, tearability can be improved by providing an easy-to-open line in the laminate as described above, and tearability can be further improved by using the sealant layer of the above embodiment.

In this specification, the melting point of a layer is a value determined in accordance with JIS K7121:2012 using a differential scanning calorimeter. Specifically, a sample is taken from each layer of the sealant layer, and the melting point is measured by the method described in the Examples section.

(first layer)
The first layer in the sealant layer contains an ethylene/α-olefin copolymer as a main component and has a melting point of 112° C. or lower. Thereby, as described above, the low-temperature sealing properties of the sealant layer can be improved. The first layer is one surface layer of the sealant layer and also one surface layer of the laminate. The first layer is the layer facing the contents contained in the packaging bag.

Examples of the ethylene/α-olefin copolymer include linear polyethylene. Linear polyethylene is a copolymer of ethylene and α-olefin, which is obtained using, for example, a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst. The linear polyethylene having a density of 0.930 g/cm ³ or less is, for example, linear low density polyethylene.

The α-olefin that is a comonomer of the above copolymer is, for example, an α-olefin having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1- Examples include nonene and 4-methylpentene, and tearability tends to improve as the number of carbon atoms increases. In consideration of low-temperature sealability and tearability, 1-hexene and 1-octene are preferred as the α-olefin.

Polyethylene can be produced using, for example, a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst as a polymerization catalyst. A single-site catalyst is a catalyst capable of forming uniform active species, and is usually prepared by bringing a metallocene transition metal compound or a non-metallocene transition metal compound into contact with an activation cocatalyst. Single-site catalysts are preferable compared to multi-site catalysts because they have a uniform structure of active sites and can yield polymers with high molecular weight and highly uniform structures. As the single site catalyst, a metallocene catalyst is preferred. In addition, by using an ethylene/α-olefin copolymer produced using a metallocene catalyst in the first layer, an ethylene/α-olefin copolymer produced using a Ziegler-Natta catalyst can be used. For example, low-temperature sealing performance can be further improved than in the case of the conventional method. By using an ethylene/α-olefin copolymer produced using a metallocene catalyst in the second layer or third layer described below, the ethylene/α-olefin copolymer produced using a Ziegler-Natta catalyst can be used. For example, impact resistance can be improved more than when a polymer is used.

From the viewpoint of low-temperature sealing properties of the sealant layer, the melting point of the first layer is preferably 110°C or lower, more preferably 105°C or lower, even more preferably 100°C or lower, and may be 80°C or higher, or even 90°C or higher. For example, the temperature may be 80°C or higher and 110°C or lower.

The difference between the melting point of the second layer and the first layer is preferably 4°C or higher, more preferably 15°C or higher, and even more preferably 20°C, from the viewpoint of the low-temperature sealing property and rigidity balance of the sealant layer. The temperature is preferably 50°C or lower, more preferably 48°C or lower, still more preferably 46°C or lower, and may be, for example, 40°C or lower, for example, 4°C or higher and 50°C or lower.

The density of the first layer is preferably 0.915 g/cm ³ or less, more preferably 0.912 g/cm ³ or less, even more preferably 0.908 g/cm ³ or less, and even 0.890 g/cm ³ or more. It may be 0.900 g/cm ³ or more, for example, 0.890 g/cm ³ or more and 0.915 g/cm ³ or less. By setting the density of the first layer to 0.915 g/cm ³ or less, for example, the low-temperature sealing properties of the sealant layer can be improved. By setting the density of the first layer to 0.890 g/cm ³ or more, for example, the blocking resistance of the laminate can be improved.

The content of the ethylene/α-olefin copolymer in the first layer is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 90% by mass or more.

In one embodiment ^, ^the first layer ^is an ethylene/α- Contains olefin copolymer. The density of the ethylene/α-olefin copolymer is preferably 0.890 g/cm ³ or more, more preferably 0.895 g/cm ³ or more. The density is, for example, 0.890 g/cm ³ or more and 0.912 g/cm ³ or less. When the first layer contains an ethylene/α-olefin copolymer having a density of 0.912 g/cm ³ or less, the low-temperature sealing properties of the sealant layer can be improved, for example. When the density of the ethylene/α-olefin copolymer is 0.890 g/cm ³ or more, the blocking resistance of the laminate can be improved, for example.

The thickness of the first layer may be 5 μm or more, 15 μm or more, 50 μm or less, 30 μm or less, for example, 5 μm or more and 50 μm or less. The first layer may be a single layer or a multilayer with each layer having the same composition. If the first layer is multilayer, the thickness of the first layer is the total thickness of each layer.

The ratio of the thickness of the first layer to the thickness of the sealant layer is preferably 3% or more, more preferably 5% or more, even more preferably 10% or more, particularly preferably 15% or more, and preferably 40%. The content is more preferably 35% or less, still more preferably 30% or less, particularly preferably 25% or less, for example 3% or more and 40% or less. Thereby, for example, the balance between low-temperature sealing performance and rigidity of the sealant layer can be further improved.

In one embodiment, the first layer is preferably in contact with the second layer or the third layer, and more preferably in contact with the second layer. That is, in one embodiment, the first layer is preferably in contact with the second layer or the third layer without an adhesive layer interposed therebetween.
In one embodiment, the first layer is an unstretched resin layer.

The first layer may contain the above additive.

(Second layer)
The second layer in the sealant layer contains polyethylene as a main component and has a melting point of 114° C. or higher. Thereby, as described above, the rigidity of the sealant layer can be improved.

From the viewpoint of the rigidity of the sealant layer, the melting point of the second layer is preferably 117°C or higher, more preferably 120°C or higher, and may be 150°C or lower, or 135°C or lower.

The density of the second layer is preferably 0.916 g/cm ³ or more, more preferably 0.917 g/cm ³ or more, even more preferably 0.920 g/cm ³ or more, particularly preferably 0.930 g/cm ³ or more. It may be 0.950 g/cm ³ or less, 0.945 g/cm ³ or less, for example, 0.916 g/cm ³ or more and 0.950 g/cm ³ or less. By setting the density of the second layer to 0.916 g/cm ³ or more, for example, the rigidity and tearability of the sealant layer can be improved. By setting the density of the second layer to 0.950 g/cm ³ or less, for example, the impact resistance of the sealant layer can be improved.

The content of polyethylene in the second layer is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more.

The second layer, in one embodiment, preferably contains polyethylene having a density of 0.915 g/cm ³ or more, more preferably 0.935 g/cm ^{3 or} more. The density of the polyethylene is preferably 0.970 g/cm ³ or less, more preferably 0.960 g/cm ³ or less. The density may be, for example, 0.915 g/cm ³ or more and 0.970 g/cm ³ or less. When the second layer contains polyethylene having a density of 0.915 g/cm ³ or more, for example, the rigidity and tearability of the sealant layer can be improved. When the density of the polyethylene is 0.970 g/cm ³ or less, for example, the impact resistance of the sealant layer can be improved.

The second layer may contain an ethylene/α-olefin copolymer as the polyethylene. The content of the ethylene/α-olefin copolymer in the second layer is preferably 50% by mass or more, more preferably 70% by mass or more, and preferably 90% by mass, based on the entire second layer. The content is more preferably 80% by mass or less, for example 50% by mass or more and 90% by mass or less. By controlling the content of the ethylene/α-olefin copolymer to 50% by mass or more, for example, the impact resistance of the sealant layer can be improved. By controlling the content of the ethylene/α-olefin copolymer to 90% by mass or less, for example, the tearability of the sealant layer can be improved.

The second layer may contain an ethylene homopolymer as the polyethylene. The content ratio of the ethylene homopolymer in the second layer is preferably 10% by mass or more, more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 15% by mass or more, based on the entire second layer. Preferably it is 25% by mass or less, for example 10% by mass or more and 50% by mass or less. By setting the content of the ethylene homopolymer to 10% by mass or more, for example, the tearability of the sealant layer can be improved. By controlling the content of the ethylene homopolymer to 50% by mass or less, for example, the impact resistance of the sealant layer can be improved.

In one embodiment, when the sealant layer is composed of two layers, the second layer is the surface layer of the sealant layer on the stretched base material side. In one embodiment, when the sealant layer is composed of three or more layers, the second layer is a surface layer and/or an intermediate layer on the stretched substrate side in the sealant layer. In this case, the first layer and the intermediate layer are preferably made of different constituent materials from the viewpoint of the balance between low-temperature sealability and rigidity.

The intermediate layer means a layer located between one surface layer and the other surface layer of the sealant layer. The intermediate layer may be a single layer or a multilayer. When the intermediate layer is multilayered, the composition of each intermediate layer may be the same or different.

The second layer may be a plurality of layers in the sealant layer as long as it contains polyethylene as a main component and has a melting point of 114° C. or higher. For example, both the surface layer and the intermediate layer on the stretched base material side may be the second layer.

The thickness of the second layer may be 10 μm or more, 45 μm or more, 250 μm or less, 170 μm or less, for example, 10 μm or more and 250 μm or less. If the second layer is multilayer, the thickness of the second layer is the total thickness of each layer.

In one embodiment, the second layer is an unstretched resin layer.

The second layer may contain the above additive.

(Third layer)
The sealant layer may further include a third layer in addition to the first layer and the second layer. The third layer is a layer containing polyethylene as a main component, and is a layer that does not correspond to the first layer or the second layer.

In one embodiment, the third layer is a surface layer and/or an intermediate layer on the side of the stretched substrate.
The third layer may be a plurality of layers within the sealant layer.

In one embodiment, the third layer is an unstretched resin layer.

The third layer may contain the above additive.

(Structure of sealant layer)
For example, the layer structure of the sealant layer containing polyethylene as a main component is as follows:
・First layer/second layer,
・First layer/second layer/first layer,
・First layer/second layer/second layer,
・First layer/second layer/third layer,
・First layer/third layer/second layer,
can be mentioned. "/" means between layers.

For example, when the sealant layer includes a first layer, an intermediate layer, and a surface layer on the stretched base material side, it is preferable that the melting point of the intermediate layer is higher than the melting point of the surface layer on the stretched base material side. Further, it is preferable that the melting point of the intermediate layer is higher than that of the first layer. Further, it is preferable that the melting point of the surface layer on the stretched base material side is higher than the melting point of the first layer. With such a configuration, for example, the low-temperature sealability, rigidity, and impact resistance of the sealant layer can be further improved.

For example, the difference between the melting point of the intermediate layer and the melting point of the surface layer on the stretched base material side may be 0°C or more and 30°C or less, 1°C or more, 2°C or more, or 25°C or less, or 20°C or more. The temperature may be below 15°C, or below 10°C. For example, the difference between the melting point of the intermediate layer and the first layer may be 2°C or more and 50°C or less, 4°C or more, 15°C or more, or 40°C or less, or 35°C or less. good. For example, the difference between the melting point of the surface layer on the stretched base material side and the melting point of the first layer may be 2°C or more and 40°C or less, 4°C or more, 15°C or more, or 35°C or less. , 30°C or lower.

In a sealant layer comprising a first layer, an intermediate layer, and a surface layer on the stretched base material side, the ratio of the thickness of the first layer to the thickness of the sealant layer and the thickness of the surface layer on the stretched base material side are The proportions are each independently preferably 3% or more, more preferably 5% or more, even more preferably 10% or more, particularly preferably 15% or more, preferably 40% or less, more preferably 35% or less, and Preferably it is 30% or less, particularly preferably 25% or less, for example 3% or more and 40% or less.

In a sealant layer comprising a first layer, an intermediate layer, and a surface layer on the stretched base material side, the ratio of the thickness of the intermediate layer to the thickness of the sealant layer is preferably 20% or more, more preferably 30% or more. , more preferably 40% or more, particularly preferably 50% or more, preferably 94% or less, more preferably 90% or less, even more preferably 80% or less, particularly preferably 70% or less, for example 20% or more It is 94% or less.

In one embodiment, the sealant layer does not have an adhesive layer between each layer selected from the first layer, the second layer, and optionally the third layer constituting the sealant layer. For example, the sealant layer is a coextruded resin film.

The content of the ethylene/α-olefin copolymer in the sealant layer is preferably 50% by mass or more, more preferably 70% by mass or more, and preferably 90% by mass or less, more preferably is 80% by mass or less, for example, 50% by mass or more and 90% by mass or less. By controlling the content of the ethylene/α-olefin copolymer to 50% by mass or more, for example, the impact resistance of the sealant layer can be improved. By controlling the content of the ethylene/α-olefin copolymer to 90% by mass or less, for example, the tearability of the sealant layer can be improved.

The content of the ethylene homopolymer in the sealant layer is preferably 10% by mass or more, more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 25% by mass, based on the entire sealant layer. % or less, for example, 10% by mass or more and 50% by mass or less. By setting the content of the ethylene homopolymer to 10% by mass or more, for example, the tearability of the sealant layer can be improved. By controlling the content of the ethylene homopolymer to 50% by mass or less, for example, the impact resistance of the sealant layer can be improved.

A surface treatment may be applied to the surface of the sealant layer located on the opposite side of the first layer. Thereby, adhesion between adjacent layers can be improved. Specific examples of the surface treatment are as described above.

<Adhesive layer>
The laminate of the present disclosure may include an adhesive layer between arbitrary layers, such as between the stretched base material and the sealant layer, for example, between the heat generating layer and the sealant layer. Thereby, the adhesiveness between the stretched base material and the sealant layer can be improved.

The thickness of the adhesive layer may be 0.1 μm or more, 0.2 μm or more, 0.5 μm or more, 10 μm or less, 8.0 μm or less, 6.0 μm or less, for example 0. The thickness may be 1 μm or more and 10 μm or less. The thickness of the adhesive layer may be 2.0 μm or less.

In one embodiment, the adhesive layer may be an adhesive layer made 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.

Examples of solvent-free adhesives, that is, non-solvent laminating adhesives, include polyether adhesives, polyester adhesives, silicone adhesives, epoxy adhesives, and urethane adhesives. Among these, urethane adhesives are preferred, and two-component curing type urethane adhesives are more preferred.

In one embodiment, the solvent-free adhesive is a two-component curing adhesive that includes a base agent and a curing agent. The weight average molecular weight (Mw) of the polymer component contained in the base resin is preferably 800 or more and 10,000 or less, more preferably 1,200 or more and 4,000 or less, from the viewpoint of coating suitability. The polydispersity (Mw/Mn) of the polymer component contained in the base agent is preferably 2.8 or less, more preferably 1.2 or more and 2.7 or less, even more preferably 1.5 or more and 2.6 or less, especially Preferably it is 2.0 or more and 2.5 or less. Here, Mn is the number average molecular weight of the polymer component contained in the base resin. Each average molecular weight is measured by gel permeation chromatography (GPC) in accordance with JIS K7252-1:2008, and is a value in terms of polystyrene.

Examples of solvent-based adhesives include rubber adhesives, vinyl adhesives, olefin adhesives, silicone adhesives, epoxy adhesives, phenolic adhesives, and urethane adhesives.

In one embodiment, by forming the adhesive layer using a solvent-free adhesive, the amount of residual solvent, specifically, the amount of residual organic solvent in the laminate can be further reduced, for example. Examples of organic solvents include hydrocarbon solvents such as toluene, xylene, n-hexane, and methylcyclohexane; ester solvents such as ethyl acetate, n-propyl acetate, n-butyl acetate, and isobutyl acetate; methanol, ethanol, isopropyl alcohol, Alcohol solvents such as n-butyl alcohol and isobutyl alcohol; and ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone.

In one embodiment, by using a solvent-free adhesive, the adhesive layer can be made thinner, for example, than when a solvent-based adhesive is used. Thereby, the content ratio of polyolefin in the entire laminate can be further improved. Such a laminate is suitable for producing a monomaterial packaging bag. In one embodiment, by using a solvent-free adhesive, the tearability of the laminate can be improved more than when using a solvent-based adhesive.

Hereinafter, a two-component curing type urethane adhesive will be explained. As this urethane adhesive, for example, an adhesive having a base agent containing a polyol compound such as a polyester polyol and a curing agent containing an isocyanate compound is preferable.

Examples of polyol compounds include polyester polyols, polyether polyols, polycarbonate polyols, and (meth)acrylic polyols. Among these, polyester polyols are preferred.

A polyester polyol has two or more hydroxyl groups in one molecule. A polyester polyol has, for example, a polyester structure or a polyester polyurethane structure as a main skeleton. Polyester polyols can be obtained, for example, by dehydration condensation reaction, transesterification, or ring-opening reaction between a polyhydric alcohol component and a polyhydric carboxylic acid component.

Examples of the polyhydric alcohol component include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6- Diols such as hexanediol, neopentyl glycol and cyclohexanedimethanol; trifunctional or higher functional polyols such as glycerin, triethylolpropane, trimethylolpropane, pentaerythritol and sorbitol.

Examples of the polycarboxylic acid component include aliphatic polycarboxylic acids, alicyclic polycarboxylic acids, aromatic polycarboxylic acids, and ester derivatives and acid anhydrides thereof. Examples of the aliphatic polycarboxylic acids include aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, and dimer acid. Examples of the alicyclic polycarboxylic acids include 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid. Examples of aromatic polycarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, and 1,2-bis(phenoxy)ethane-p , p'-dicarboxylic acid.

The polyester polyol can also be lengthened in advance with polyisocyanate, if necessary. Examples of polyisocyanates include 1,6-hexamethylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, m-xylylene diisocyanate, α, α, α'α'-tetramethyl-m-xylylene diisocyanate, tolylene diisocyanate, and naphthalene. Diisocyanates such as diisocyanates and diphenylmethane diisocyanate; and biurets, nurates, or trimethylolpropane adducts of diisocyanates can be mentioned.

From the viewpoint of coating suitability, the weight average molecular weight (Mw) of the polyol compound such as polyester polyol is preferably 800 or more and 10,000 or less, more preferably 1,200 or more and 4,000 or less. The polydispersity (Mw/Mn) of the polyol compound such as polyester polyol is preferably 2.8 or less, more preferably 1.2 or more and 2.7 or less, still more preferably 1.5 or more and 2.6 or less, particularly preferably is 2.0 or more and 2.5 or less. Here, Mn is the number average molecular weight of the polyol compound. Each average molecular weight is measured by gel permeation chromatography (GPC) in accordance with JIS K7252-1:2008, and is a value in terms of polystyrene.

The isocyanate compound has two or more isocyanate groups in one molecule. Examples of the isocyanate compound include aromatic isocyanates and aliphatic isocyanates. The isocyanate compound may be a blocked isocyanate compound obtained by addition reaction using a known isocyanate blocking agent by a known and commonly used method.

Examples of the isocyanate compound include tetramethylene diisocyanate, hexamethylene diisocyanate, norbornene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, m-xylylene diisocyanate, hydrogenated xylylene diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, and α, Diisocyanates such as α,α'α'-tetramethyl-m-xylylene diisocyanate; trimers of these diisocyanates; and these diisocyanate compounds and low-molecular active hydrogen compounds or their alkylene oxide adducts, or polymeric active compounds. Examples include an adduct, a burette, and an allophanate, which are obtained by reacting with a hydrogen compound.

Examples of low-molecular active hydrogen compounds include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, neneopentyl glycol, 1,6-hexamethylene glycol, 1,8-octamethylene glycol, 1,4-Cyclohexane dimethanol, metaxylylene alcohol, 1,3-bishydroxyethylbenzene, 1,4-bishydroxyethylbenzene, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, erythritol, sorbitol, ethylenediamine, monoethanol Amines include diethanolamine, triethanolamine and metaxylylene diamine. Examples of the polymeric active hydrogen compound include polyester, polyether polyol, and polyamide.

The adhesive layer may be an adhesive resin layer containing a thermoplastic resin. Examples of thermoplastic resins include high-density polyethylene, medium-density polyethylene, high-pressure low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, and ethylene-vinyl acetate copolymer. Methyl (meth)acrylate copolymer, ethylene-ethyl (meth)acrylate copolymer, ethylene-maleic acid copolymer, ionomer resin, and polyolefin with unsaturated carboxylic acid, unsaturated carboxylic acid anhydride, or monoester. Examples include resins obtained by graft polymerization or copolymerization of polymers. The thermoplastic resin may be a fossil fuel-derived material, a biomass-derived material, or both.

In one embodiment, the laminate of the present disclosure may be manufactured by bonding a stretched base material and a resin film corresponding to the sealant layer by a non-solvent laminating method using a solvent-free adhesive. They may be manufactured by bonding them together by a dry lamination method using a solvent-based adhesive.

<Layer configuration of laminate>
Hereinafter, several examples will be given of the layer structure of the laminate according to the first aspect of the present disclosure.
The laminate 30 shown in FIG. 1 includes a stretched base material 40 including a polyolefin layer 42, a polyolefin layer 42, an adhesive resin layer 44, and a heat generating resin layer 46, an adhesive layer 60, and a sealant layer 70. Prepare in this order. The laminate 30 shown in FIG. 1 may further include a heat generating layer 80 (not shown) between the stretched base material 40 and the adhesive layer 60. The stretched base material 40 may include a polyolefin layer 42, an adhesive resin layer 44, a heat generating resin layer 46, an adhesive resin layer 44, and a polyolefin layer 42, as shown in FIG.

The laminate 30 shown in FIG. 3 includes a stretched base material (polyolefin base material) 40, a heat-generating resin layer 50, an adhesive layer 60, and a sealant layer 70 in this order. The laminate 30 shown in FIG. 3 further includes a heat generating layer 80 (not shown) between the heat generating resin layer 50 and the adhesive layer 60 and/or between the stretched base material 40 and the heat generating resin layer 50. It's okay.

The laminate 30 shown in FIG. 4 includes a heat-generating resin layer 50, a stretched base material (polyolefin base material) 40, an adhesive layer 60, and a sealant layer 70 in this order. The laminate shown in FIG. 4 may further include a heat generating layer 80 (not shown) between the stretched base material 40 and the adhesive layer 60.

In FIGS. 3 and 4, the stretched base material 40 may have a multilayer structure. In FIGS. 3 and 4, an anchor coat layer (not shown) may be provided between the exothermic resin layer 50 and the stretched base material 40.

Hereinafter, specific examples will be given regarding the layer structure of the laminate according to the second aspect of the present disclosure. The laminate 30 shown in FIG. 15 includes a stretched base material 40, a heat generating layer 50, an adhesive layer 60, and a sealant layer 70 in this order. In FIG. 15, the stretched base material 40 may have a multilayer structure. The sealant layer 70 in FIG. 15 has a layer structure shown in FIGS. 16 to 18, for example.

The sealant layer 70 shown in FIG. 16 includes a first layer 72 as a sealing layer and a second layer 74 as a laminate layer in this order. The sealant layer 70 shown in FIG. 17 includes a first layer 72 as a sealing layer, a second layer 74 as an intermediate layer, and a second layer 74 as a laminate layer in this order. The two second layers 74 may be the same or different from each other. The sealant layer 70 shown in FIG. 18 includes, in this order, a first layer 72 as a sealing layer, a second layer 74 as an intermediate layer, and a third layer 76 as a laminate layer.

[Packaging bag]
The laminate of the present disclosure can be suitably used for packaging material applications. Packaging materials are used to make packaging bags. By using at least the laminate of the present disclosure, a packaging bag with excellent tearability can be manufactured. The packaging bag may be a refill pouch, particularly a standing pouch, that accommodates fluid contents such as liquid or powder that is refilled into a container such as a bottle.

Examples of packaging bags include standing pouch type, side seal type, two side seal type, three side seal type, four side seal type, envelope sticker type, gasho sticker type (pillow seal type), pleated seal type, and flat bottom seal type. There are various types of packaging bags, such as a type, a square bottom seal type, and a gusset type.

The packaging bag of the present disclosure includes the laminate of the present disclosure.
The packaging bag of the present disclosure is
a storage section that accommodates the contents;
a sealing part where the sealant layers of the laminate are joined;
and an easy-to-open line that includes the altered portion of the laminate.
The seal portion includes an inner edge that defines a housing portion.
The easy-to-open line is a line that includes a first intersection point and a second intersection point that intersect with the inner edge of the seal portion, and crosses the storage portion when the packaging bag is viewed from above.
The packaging bag may further include a notch that serves as a starting point for tearing.

<Seal part>
The packaging bag has a seal portion where the sealant layers of the laminate are joined together. Examples of methods for forming the seal portion include heat sealing, in which the sealant layers of the laminate are melted by heating and the sealant layers are fused together, and specifically, bar seals, rotating roll seals, belt seals, Impulse seals, high frequency seals and ultrasonic seals may be mentioned.

<Easy-to-open line>
The packaging bag has an easy-to-open line as a path for tearing the packaging bag.
The easy-to-open line includes a deteriorated portion, which is a portion where the laminate has deteriorated in quality.
The width W1 of the altered part included in the easy-to-open line is preferably 30 μm or more, more preferably 50 μm or more, even more preferably 70 μm or more, and may be 250 μm or less, 230 μm or less, 200 μm or less, for example 30 μm or more. It may be 250 μm or less. Thereby, for example, the ease of opening the packaging bag can be improved. The width W1 is measured at the end surface of the stretched base material on the sealant layer side. The width W1 tends to increase as the energy absorbed from the laser by the exothermic resin layer or the exothermic layer increases.
A specific example of the method for calculating the width W1 will be described later.

The laminate that constitutes the packaging bag may have two or more easy-to-open lines. The number of easy-to-open lines may be 1 or more, 2 or more, 3 or more, 10 or less, 8 or less, 5 or less, for example, 1 or more and 10 or less. The easy-to-open line may be formed on both the front film and the back film, which will be described later. In this case, the front film and the back film may each have the above number of easy-to-open lines.

The easy-open line including the altered portion can be formed, for example, by irradiating the laminate that constitutes the packaging bag with a laser. The reason why altered parts are formed in the laminate is presumed to be as follows. When the laminate is irradiated with a laser, the heteroatom-containing resin contained in the exothermic resin layer or the exothermic substance contained in the exothermic layer absorbs the laser, thereby increasing the temperature of the exothermic resin layer or the exothermic layer. As a result, gas is generated around the heated heat-generating resin layer or heat-generating layer, for example. When the temperature of the gas rises and the pressure of the gas increases, a portion of the stretched base material scatters, forming an altered part. The altered portion may penetrate the stretched base material, may further penetrate the heat-generating resin layer or the heat-generating layer, or may further penetrate the adhesive layer. Even if a through-hole is not formed, an altered portion may be formed, for example, by expansion of the heat-generating resin layer or heat-generating layer and the stretching base material being partially raised or peeled off. Note that the altered portion may be formed according to another principle.

Laser irradiation can be performed while moving the laser irradiation position in the laminate. For example, a laser irradiation device that emits a laser toward the laminate may be moved relative to the laminate. As a result, an altered portion is formed along the movement path of the laser irradiation device. As a result, an easy-to-open line extending in a direction corresponding to the movement path of the laser irradiation device is formed in the laminate. The relative movement may include moving the laser irradiation device with respect to the stacked body, and may include moving the stacked body with respect to the laser irradiation device. Furthermore, the irradiation position of the laser on the stacked body may be moved by changing the trajectory of the laser using a galvanometer mirror or the like.

The laminate may be irradiated with a laser from the sealant layer side.
The laminate may be irradiated with a laser from the stretched base material side.

The scanning speed of laser irradiation may be 10 mm/s or more, 20 mm/s or more, or 50 mm/s or more. By setting the scanning speed to a certain value or higher, for example, it is possible to prevent the exothermic resin layer or the exothermic layer from absorbing excessive laser energy. Thereby, it is possible to suppress damage to the sealant layer, and it is also possible to suppress the width W1 of the altered portion from becoming too large. The scanning speed of laser irradiation can be appropriately selected depending on the type and wavelength of the laser.

The scanning speed of laser irradiation may be 2000 mm/s or less, 1500 mm/s or less, or 1000 mm/s or less. Thereby, for example, the heat-generating resin layer or the heat-generating layer can appropriately absorb laser energy.

The output of the laser may be 1 W or more, 2 W or more, 100 W or less, 80 W or less, 50 W or less, for example, 1 W or more and 100 W or less. The line width of the laser may be 40 μm or more, 60 μm or more, 500 μm or less, 200 μm or less, 100 μm or less, for example, 40 μm or more and 500 μm or less.

The laser may be a UV laser, a visible light laser, or an infrared laser. The wavelength of the laser may be 200 nm or more, 300 nm or more, 500 nm or more, 800 nm or more, 1000 nm or more, 20 μm or less, 15 μm or less, 2000 nm or less, 1800 nm or less, The thickness may be 1500 nm or less, for example, 200 nm or more and 20 μm or less.

Examples of lasers include fiber lasers, YAG lasers, YVO ₄ lasers, semiconductor lasers, and carbon dioxide lasers (CO ₂ lasers). From the viewpoint of tearability (particularly the tearability in the diagonal direction of 45°, which will be described later), a fiber laser is preferable, and from the viewpoint of productivity, a CO ₂ laser is preferable.

<Contents>
Examples of the contents accommodated in the packaging bag include liquids, solids, powders, and gels. The contents may be food or drink products, or non-food or drink products such as chemicals, cosmetics, pharmaceuticals, metal parts, and electronic parts. After the contents are placed in the packaging bag, the packaging bag can be sealed by heat-sealing the opening of the packaging bag.

Contents include, for example, shampoo, conditioner, conditioner, hand soap, body soap, fragrance, deodorant, deodorant, insect repellent, detergent; sauce, soy sauce, dressing, cooking oil, mayonnaise, ketchup, syrup, and cooking. Alcoholic beverages, other liquid or viscous seasonings; fruit juices; spices; liquid drinks, jelly drinks, liquid soups, powdered soups, instant foods, other food and drinks; creams; metal parts and electronic parts. .

<Preparation of packaging bag>
In one embodiment, a packaging bag is produced by folding the laminate of the present disclosure in half so that the stretched base material is on the outside and the sealant layer is on the inside, stacking them on top of each other, and heat-sealing the edges and the like. can. In another embodiment, a packaging bag can be produced by stacking a plurality of laminates of the present disclosure so that the sealant layers face each other and heat-sealing the ends and the like. The entire packaging bag may be composed of the above-mentioned laminate, or a part of the packaging bag may be composed of the above-mentioned laminate.

<Embodiment of packaging bag>
Hereinafter, several examples of embodiments of the packaging bag of the present disclosure will be described based on the drawings.
FIG. 5 is a front view showing the packaging bag 10 of one embodiment. FIG. 5 shows the packaging bag 10 in a state before it is filled with contents (in a state in which no contents are accommodated). The packaging bag 10 is a gusset-type pouch configured to be self-supporting. The packaging bag 10 includes an upper part 11, a lower part 12, and a side part 13, and has a substantially rectangular outline in a front view. Names such as "upper part,""lowerpart," and "side part," and terms such as "upper part" and "lower part" are based on the state in which the packaging bag 10 stands on its own with the gusset section facing down. It is merely a relative representation of the positions and directions of 10 and its constituent elements. The posture of the packaging bag 10 during transportation or use is not limited by the names and terms used in this specification.

The packaging bag 10 has a storage section 17, a seal section 19, and an easy-to-open line 26. The storage section 17 stores contents. The seal portion 19 includes an inner edge 19x that defines the housing portion 17. The seal portion 19 is constructed by joining together the sealant layers of the laminate that constitutes the packaging bag 10. In a plan view such as FIG. 5, the seal portion 19 is hatched.

The accommodating part 17 may include a spout part 20. The spout portion 20 is a portion through which the contents are taken out from the packaging bag 10. The width of the spout portion 20 is narrower than the width of the other portions of the accommodating portion 17. Therefore, the user can accurately determine the direction in which the contents are poured out from the packaging bag 10 through the spout section 20.

The easy-to-open line 26 is formed on the packaging bag 10 in order to improve the tearability of the packaging bag 10. The easy-to-open line 26 crosses the accommodating portion 17 when the packaging bag 10 is viewed from above. The direction of the easy-to-open line 26 that crosses the accommodating portion 17 is not particularly limited, and may be, for example, the MD direction of the laminate, or a direction at any angle with respect to the MD direction (for example, the TD direction or a 45° direction). In the example shown in FIG. 5, the easy-to-open line 26 crosses the spout portion 20 in plan view. As shown in FIG. 5, a cutout 28 adjacent to the easy-open line 26 may be formed at the outer edge of the packaging bag 10. Instead of the notch 28, a notch may be formed on the outer edge of the packaging bag 10.

When the user tears the packaging bag 10 along the easy-open line 26, shearing force is applied to the film constituting the packaging bag 10. The film is torn as the sealant layer 70 breaks along the easy-open line 26. Tearability refers to the ease with which the packaging bag 10 breaks due to shearing force applied to the film. When the film has high tearability, the film of the packaging bag 10 can be broken along the easy-open line 26 by the user applying an appropriate shearing force to the packaging bag 10. When the film has low tearability, even if a user applies a large shearing force to the packaging bag 10, the packaging bag 10 is unlikely to break along the easy-open line 26. For example, the shearing force applied to the packaging bag 10 is used as a force to stretch some layers of the packaging bag 10, or as a force to peel some layers of the packaging bag 10 from other layers. Therefore, the film is difficult to break.

The packaging bag 10 includes a front film 14 constituting the front surface, a back film 15 constituting the back surface, and a lower film 16 constituting the lower part 12. The lower film 16 is placed between the front film 14 and the back film 15 in a folded state at the folded portion 16f.

Either or both of the front film 14 and the back film 15 are constituted by the laminate 30 of the present disclosure. The lower film 16 may also be comprised of the laminate 30 of the present disclosure. In one embodiment, the laminate 30 includes a stretched base material 40, a heat generating resin layer or heat generating layer 50, an adhesive layer 60, and a sealant layer 70, as shown in FIG.

The laminate 30 includes an inner surface 30x and an outer surface 30y. The inner surface 30x is a surface that comes into contact with the contents. The outer surface 30y is a surface located on the opposite side of the inner surface 30x. The sealant layer 70 is located on the inner surface 30x side with respect to the stretched base material 40. The heat generating resin layer or heat generating layer 50 is located between the stretched base material 40 and the sealant layer 70.

The terms "front film", "back film", and "lower film" are merely divisions of each film according to their positional relationship, and the method of providing the film when manufacturing the packaging bag 10 is defined by the above-mentioned terms. is not limited by. For example, the packaging bag 10 may be manufactured using one film in which the front film 14, the back film 15, and the lower film 16 are arranged in series, or the packaging bag 10 in which the front film 14 and the lower film 16 are arranged in series. It may be manufactured using a total of two films, one film and one back film 15, or a total of three films, one front film 14, one back film 15, and one bottom film 16. It may also be manufactured using a film.

As shown in FIG. 5, the seal portion 19 includes a lower seal portion 12a, a side seal portion 13a, and a spout seal portion 20a. The lower seal portion 12a extends to the lower portion 12. The side seal portion 13a extends along the pair of side portions 13. The spout seal portion 20a defines the spout portion 20. The distance between the inner edges of the spout seal portions 20a is smaller than the distance between the inner edges of the pair of side seal portions 13a. When the spout part 20 is formed at a corner between the top 11 and the side part 13 of the packaging bag 10, the spout seal part 20a is connected to the side seal part 13a.

As shown in FIG. 5, in the packaging bag 10 in which no contents are stored, the upper part 11 of the packaging bag 10 has an opening 11b. After the contents are stored in the packaging bag 10 through the opening 11b, the sealant layer of the front film 14 and the sealant layer of the back film 15 are joined at the upper part 11, thereby forming an upper seal part in the opening 11b. Ru. Thereby, the accommodating portion 17 is sealed from the outside of the packaging bag 10.

The side seal part 13a, spout seal part 20a, and top seal part are constructed by joining the sealant layer of the front film 14 and the sealant layer of the back film 15. The lower seal portion 12a includes a portion where the sealant layer of the front film 14 and a sealant layer of the lower film 16 are joined, and a portion where the sealant layer of the back film 15 and the sealant layer of the lower film 16 are joined. include. As shown by the dotted line labeled 13c in FIG. 5, a cutout may be formed in a portion of the lower film 16. At the position of the notch, the sealant layer of the front film 14 and the sealant layer of the back film 15 may be joined.

The easy-to-open line 26 will be explained in detail. FIG. 6 is a diagram showing the easy-to-open line 26 formed on the surface film 14. FIG. 6 is a cross-sectional view showing a case where the surface film 14 is cut along a direction perpendicular to the direction in which the easy-to-open line 26 extends, as indicated by the symbol A in FIG. Although not shown, an easy-to-open line 26 may also be formed on the back film 15. The easy-to-open line 26 of the front film 14 and the easy-to-open line 26 of the back film 15 may overlap when viewed along the normal direction of the front film 14. The easy-to-open line 26 includes a through hole 27 that penetrates the stretched base material 40 . The easy-to-open line 26 is formed by irradiating the laminate 30 with a laser. As shown in FIG. 8, the packaging bag 10 may have a plurality of easy-to-open lines 26 that cross the accommodating portion 17.

A method for calculating the width of the altered portion will be explained with reference to FIG. 7. As shown in FIG. 7, the easy-to-open line 26 intersects with the inner edge 19x of the seal portion 19 at a first intersection 261 and a second intersection 262. Points P1, P2, and P3 are located at boundaries when the section of the easy-to-open line 26 from the first intersection 261 to the second intersection 262 is divided into four. The packaging bag 10 is cut along a straight line that is perpendicular to the direction in which the easy-to-open line 26 extends and passes through points P1, P2, and P3. Observe the three cut surfaces and measure the width. The average value of the three width measurements is used as the width W1 of the altered portion. As a device for observing the cut surface, for example, a digital microscope VHX-6000 manufactured by Keyence Corporation is used. The observation magnification is 1000 times. The width of the altered area is measured using the length measurement function of the VHX-6000.

Next, the layer structure of the lower film 16 will be explained.
The layer structure of the lower film 16 is arbitrary as long as it has an inner surface that can be joined to the sealant layer of the front film 14 and the sealant layer of the back film 15. For example, similarly to the front film 14 and the back film 15, the above-mentioned laminate 30 may be used as the lower film 16. A film having a structure different from that of the laminate 30 of the present disclosure may be used as the lower film 16.

The packaging bag 10 can be produced, for example, as follows. A laminate 30 is prepared. Subsequently, the laminated body 30 is irradiated with a laser to form an easy-to-open line 26. The laminate 30 on which the easy-to-open line 26 is formed is cut into two. Thereby, a front film 14 and a back film 15 are obtained. Subsequently, the folded lower film 16 is inserted between the front film 14 and the back film 15. Subsequently, the sealant layers of each film are heat-sealed to form seal parts such as the lower seal part 12a, the side seal part 13a, and the spout seal part 20a. The films joined together by heat sealing are cut into appropriate shapes. Thereby, the packaging bag 10 shown in FIG. 5 is obtained.

Subsequently, the storage portion 17 of the packaging bag 10 is filled with the contents. Thereafter, the upper portion 11 is heat-sealed to form an upper sealed portion. In this way, a sealed packaging bag 10 containing the contents is obtained.

In the above description of the embodiment, an example was shown in which the packaging bag 10 is a gusset-type pouch, but the specific configuration of the packaging bag 10 is not particularly limited.

For example, the packaging bag 10 does not need to include the lower film 16, as shown in FIGS. 9 and 10. In FIGS. 9 and 10, the lower seal part 12a and the side seal part 13a of the packaging bag 10 are formed by bonding the sealant layers of the front film 14 and the back film 15, respectively, which are made of the laminate 30. After the contents are stored in the packaging bag 10, the packaging bag 10 is sealed by joining the sealant layer of the front film 14 and the sealant layer of the back film 15 at the opening 11b of the upper part 11. Also in FIGS. 9 and 10, the packaging bag 10 includes an easy-to-open line 26 that crosses the accommodating portion 17 in plan view. Thereby, the tearability of the packaging bag 10 can be improved.

As shown in FIG. 11, the packaging bag 10 may be a pillow pouch. The packaging bag 10 includes a folded palm portion 18 formed by overlapping the ends of the laminate 30 that constitutes the front film 14 and the back film 15. The palms in prayer portion 18 includes a palms in prayer portion seal portion 18a in which the sealant layers of the laminate 30 are joined together. In the example shown in FIG. 11, the easy-to-open line 26 is formed to cross the housing portion 17 and the folded palms portion 18. As shown in FIG. 11, a notch 28 or a notch (not shown) may be formed at the outer edge of the palm-to-face portion in contact with the easy-to-open line 26.

[First aspect]
The first aspect of the present disclosure relates to, for example, the following [1] to [13].
[1] A laminate including at least a stretched base material and a sealant layer, wherein the stretched base material includes at least a polyolefin layer, the sealant layer contains polyolefin as a main component, and the laminate is a heat-generating resin layer containing as a main component a heteroatom-containing resin that generates heat by absorbing A laminate located at at least one location on a surface of the stretched base material opposite to the surface facing the sealant layer.
[2] The laminate according to [1] above, wherein the heteroatom-containing resin contains at least one selected from ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and polyamide.
[3] The laminate according to [1] or [2], wherein the stretched base material includes at least the polyolefin layer, the adhesive resin layer, and the exothermic resin layer.
[4] The laminate according to any one of [1] to [3] above, wherein the laminate includes at least the stretched base material including the exothermic resin layer, an adhesive layer, and the sealant layer in this order. laminate.
[5] The laminate according to any one of [1] to [3] above, wherein the laminate includes at least the stretched base material, the exothermic resin layer, the adhesive layer, and the sealant layer in this order. laminate.
[6] The laminate according to any one of [1] to [3] above, wherein the laminate includes at least the exothermic resin layer, the stretched base material, the adhesive layer, and the sealant layer in this order. laminate.
[7] The laminate further comprises a heat generating layer containing a heat generating substance that absorbs laser and generates heat (excluding the heteroatom-containing resin that generates heat by absorbing laser) [1] to [ 6].
[8] The laminate according to [7] above, wherein the exothermic substance is at least one selected from metal oxides, bismuth-based compounds, molybdenum, molybdenum-based compounds, copper, copper-based compounds, and carbon black.
[9] The polyolefin layer of the stretched base material is a polyethylene layer, and the sealant layer contains polyethylene as a main component, or the polyolefin layer of the stretched base material is a polypropylene layer, and the sealant layer The laminate according to any one of [1] to [8] above, which contains polypropylene as a main component.
[10] The sealant layer includes at least a first layer and a second layer, the first layer containing an ethylene/α-olefin copolymer as a main component, and the first layer containing an ethylene/α-olefin copolymer as a main component. a melting point of 112° C. or lower, the second layer contains polyethylene as a main component, a melting point of the second layer is 114° C. or higher, and one surface layer of the laminate contains polyethylene as a main component; The laminate according to any one of [1] to [9] above, which is the first layer.
[11] The laminate according to [10], wherein the first layer has a density of 0.915 g/cm ³ or less, and the second layer has a density of 0.916 g/cm ³ or more.
[12] The laminate according to any one of [1] to [11], wherein the polyolefin content in the entire laminate is 80% by mass or more.
[13] A packaging bag comprising the laminate according to any one of [1] to [12] above, wherein the packaging bag includes a storage section for accommodating contents and the sealant layer of the laminate. a seal portion that is joined to each other; and an easy-to-open line that includes an altered portion of the laminate; the seal portion includes an inner edge defining the housing portion; and the easy-to-open line includes The packaging bag includes a first intersection point and a second intersection point that intersect with the inner edge of the portion, and is a line that crosses the storage portion when the packaging bag is viewed from above.

[Second aspect]
The second aspect of the present disclosure relates to, for example, the following [1] to [8].
[1] A laminate comprising at least a stretched base material and a sealant layer, the stretched base material containing polyethylene as a main component, and the sealant layer comprising at least a first layer and a second layer. wherein the first layer contains an ethylene/α-olefin copolymer as a main component, the first layer has a melting point of 112° C. or less, and the second layer contains polyethylene as a main component. the melting point of the second layer is 114°C or higher, one surface layer of the laminate is the first layer, and the laminate contains the stretched base material and the sealant layer. A laminate further comprising a heat generating layer containing a heat generating substance that absorbs laser and generates heat between the two.
[2] The laminate according to [1] above, wherein the first layer has a density of 0.915 g/cm ^{3 or} less, and the second layer has a density of 0.916 g/cm ³ or more.
[3] The exothermic substance described in [1] or [2] above is at least one selected from metal oxides, bismuth-based compounds, molybdenum, molybdenum-based compounds, copper, copper-based compounds, and carbon black. laminate.
[4] The laminate according to any one of [1] to [3] above, wherein the exothermic substance is a metal oxide.
[5] The laminate according to any one of [1] to [4], wherein the heat generating layer is a printed layer provided on the stretched base material.
[6] The laminate according to any one of [1] to [5], further comprising an adhesive layer between the heat generating layer and the sealant layer.
[7] The laminate according to any one of [1] to [6], wherein the content of polyethylene in the entire laminate is 80% by mass or more.
[8] A packaging bag comprising the laminate according to any one of [1] to [7] above, wherein the packaging bag includes a storage section for accommodating contents and the sealant layer of the laminate. a seal portion that is joined to each other; and an easy-to-open line that includes an altered portion of the laminate; the seal portion includes an inner edge defining the housing portion; and the easy-to-open line includes The packaging bag includes a first intersection point and a second intersection point that intersect with the inner edge of the portion, and is a line that crosses the storage portion when the packaging bag is viewed from above.

Hereinafter, the laminate of the present disclosure will be explained in more detail using Examples, but the laminate of the present disclosure is not limited to the following Examples.

[Preparation of stretched base material]
The following materials were used in producing the stretched base material.
・Medium density polyethylene (MDPE)
Product name: Elite5538G, manufactured by Dow Chemical, density: 0.941 g/cm ³ , melting point: 129°C, MFR: 1.3 g/10 min, high-density polyethylene (HDPE)
Product name: Elite5960G, manufactured by Dow Chemical, density: 0.960 g/cm ³ , melting point: 134°C, MFR: 0.8 g/10 min, linear low density polyethylene (LLDPE)
Product name: Elite5400G, manufactured by Dow Chemical, density: 0.916 g/cm ³ , melting point: 123°C, MFR: 1.3 g/10 minutes, adhesive resin Product name: Admer NF557, manufactured by Mitsui Chemicals,
Maleic anhydride modified polyethylene, density: 0.920g/cm ³
・Ethylene-vinyl alcohol copolymer (EVOH)
Product name: EVAL E171B, manufactured by Kuraray,
Melting point: 165°C, density: 1.14g/cm ³ ,
MFR: 1.7 g/10 min, ethylene content: 44 mol%
・Polyamide (Ny)
Product name: 5033, manufactured by Ube Industries,
Melting point: 196°C, density: 1.14g/cm ³

<Polyethylene base material>
70 parts of MDPE and 30 parts of LLDPE were mixed to obtain a blend PE (A) with an average density of 0.934 g/cm ³ . 70 parts of MDPE and 30 parts of HDPE were mixed to obtain a blended PE (B) with an average density of 0.947 g/cm ³ . LLDPE, blend PE (A), and blend PE (B) were formed by inflation molding to form blend PE (B) layer 15 μm/blend PE (A) layer 22.5 μm/LLDPE layer 50 μm/blend PE (A) 22.5 μm. / Blend PE (B) layer Co-extrusion of 5 layers with a layer thickness ratio of 15 μm was performed to form a tube-shaped film to obtain a polyethylene film with a total thickness of 125 μm, and the tube-shaped film was folded at the nip point to form two sheets. I layered it. The obtained polyethylene film was stretched 5 times in the machine direction (MD), and one of the blended PE (B) layers was subjected to corona treatment, and then the end was slit and divided into two sheets with a thickness of 25 μm. A polyethylene base material (hereinafter also referred to as "PE base material") was obtained.

<EVOH-containing base material (A)>
MDPE (Elite5538G), adhesive resin (Admer NF557), EVOH (Eval E171B), adhesive resin (Admer NF557), and MDPE (Elite 5538G) were coextruded into a film using an inflation molding method. The film was stretched 5 times in the machine direction (MD) using a stretching device to obtain an EVOH-containing base material (A). The EVOH-containing base material (A) thus obtained includes a 7 μm thick MDPE layer, a 4 μm thick adhesive resin layer, a 2.5 μm thick EVOH layer, a 4 μm thick adhesive resin layer, and a 7.5 μm thick MDPE layer in this order.
Corona treatment was performed on one MDPE layer surface.

<EVOH-containing base material (B)>
EVOH (Eval E171B), adhesive resin (Admer NF557), and MDPE (Elite5538G) are coextruded into a film using an inflation molding method, and the resulting film is stretched 5 times in the machine direction (MD) using a stretching device. The EVOH-containing base material (B) was obtained by stretching. The EVOH-containing base material (B) thus obtained consists of an EVOH layer with a thickness of 2.5 μm, an adhesive resin layer with a thickness of 3 μm, and three MDPE layers with a total thickness of 19.5 μm in this order. Be prepared.
Corona treatment was performed on the EVOH layer surface.

<EVOH-containing layer base material (C)>
EVOH (Eval E171B), adhesive resin (Admer NF557), and MDPE (Elite5538G) are coextruded into a film using an inflation molding method, and the resulting film is stretched 5 times in the machine direction (MD) using a stretching device. The EVOH-containing base material (C) was obtained by stretching. The EVOH-containing base material (C) thus obtained comprises, in this order, an EVOH layer with a thickness of 5 μm, an adhesive resin layer with a thickness of 3 μm, and three MDPE layers with a total thickness of 17 μm.
Corona treatment was performed on the EVOH layer surface.

<Ny-containing base material (D)>
A Ny-containing base material (D) was obtained in the same manner as the EVOH-containing base material (B) except that EVOH (EVAL E171B) was changed to Ny (5033). The Ny-containing base material (D) thus obtained has a Ny layer with a thickness of 2.5 μm, an adhesive resin layer with a thickness of 3 μm, and three MDPE layers with a total thickness of 19.5 μm in this order. Be prepared.
Corona treatment was performed on the Ny layer surface.

<Other stretched base materials>
PP base material: 20 μm thick biaxially oriented polypropylene base material (Toyobo, P2161)
Ny base material: 15 μm thick biaxially stretched nylon base material (Idemitsu Unitec, G-100)

[Preparation of sealant film]
The following materials were used in making the sealant film.
・Ethylene/α-olefin copolymer (hereinafter referred to as “copolymer A”)
copolymer of ethylene and C8 olefin,
Density: 0.902g/cm ³ , MFR: 1.0g/10min,
Polymerization catalyst: metallocene catalyst/ethylene/α-olefin copolymer (hereinafter referred to as “copolymer B”)
copolymer of ethylene and C8 olefin,
Density: 0.918g/cm ³ , MFR: 0.8g/10min,
Polymerization catalyst: metallocene catalyst/ethylene/α-olefin copolymer (hereinafter referred to as “copolymer C”)
copolymer of ethylene and C8 olefin,
Density: 0.941g/cm ³ , MFR: 1.3g/10min,
Polymerization catalyst: Metallocene catalyst/high pressure low density polyethylene (LDPE)
Density: 0.919g/cm ³ , MFR: 2.0g/10min・Slip agent masterbatch (slip agent MB)
Base material: polyethylene,
Slip agent: erucic acid amide, content of slip agent: 2.0% by mass,
Density: 0.921g/cm ³ , MFR: 5.4g/10min・Anti-blocking agent masterbatch (AB agent MB)
Base material: polyethylene, anti-blocking agent: acrylic resin,
Content ratio of anti-blocking agent: 30% by mass,
Density: 0.959g/cm ³ , MFR: 2.5g/10min

A mixture of 93 parts by mass of copolymer A, 1 part by mass of slip agent MB, and 6 parts by mass of AB agent MB was used as the first layer (sealing layer), and the second layer (intermediate layer) As a second layer (laminate layer), a mixture of 69 parts by mass of copolymer C, 30 parts by mass of LDPE, and 1 part by mass of slip agent MB was used, and 89 parts by mass of copolymer B was used as the second layer (laminate layer). Using a mixture of 10 parts by mass of LDPE and 1 part by mass of slip agent MB, the thickness of the first layer (sealing layer): second layer (intermediate layer): second layer (laminate layer) A sealant film (hereinafter also referred to as "PE film (A)") having a thickness of 130 μm was obtained by three-layer extrusion film forming at a ratio of 1:3:1.
Corona treatment was performed on the laminate layer surface of the PE film (A).

The melting point of each layer in the obtained PE film (A) was determined in accordance with JIS K7121:2012 using a differential scanning calorimeter based on the following method. As a result, the melting point of the first layer (seal layer) was 99°C, the melting point of the second layer (intermediate layer) was 122°C, and the melting point of the second layer (laminate layer) was 117°C. Regarding the density, the density of the first layer (sealing layer) is 0.906g/cm ³ , the density of the second layer (intermediate layer) is 0.934g/cm ³ , and the density of the second layer (laminate layer) is 0.906g/cm 3 . The density of was 0.918 g/cm ³ .

(Measurement of melting point)
The melting point of each layer in the sealant film was determined using a differential scanning calorimeter in accordance with JIS K7121:2012. As the differential scanning calorimeter, a thermal analyzer TA7000 series manufactured by Hitachi High-Tech Science Co., Ltd. was used. Specifically, samples of each layer were taken from the sealant film. Approximately 10 mg of the sample was placed in an aluminum cell, and heated at a heating rate of 10°C/min from 20°C to a temperature sufficiently higher than the melting point (for example, 200°C) in a nitrogen atmosphere, and at that temperature it was heated to 10°C. After holding for a minute, it was cooled to 20°C at a cooling rate of 10°C/min. This heating, holding, and cooling process was repeated once more, and the melting peak temperature of the maximum endothermic peak observed during the second heating was determined, and this was taken as the melting point.

<Other sealant films>
PE film (B): unstretched polyethylene film with a thickness of 130 μm (sealing layer with a density of 0.911 g/cm ³ , intermediate layer with a density of 0.937 g/cm ³ , and laminate layer with a density of 0.926 g/cm ³ ) (a polyethylene film having a sealing layer:intermediate layer:laminate layer thickness ratio of 1:3:1)
PP film: 80 μm thick unstretched polypropylene film (Toray Film Processing, ZK-207)

[glue]
The following adhesive was used.
Solvent-free adhesive (NSL): Manufactured by Rock Paint, 2-part curable urethane-based solvent-free adhesive, main ingredient: RN-920, curing agent: HN-920 = 1:1. The weight average molecular weight (Mw) of the polymer component contained in the base resin is in the range of 2,000 to 2,500, and the polydispersity (Mw/Mn) of the polymer component contained in the base resin is 2.0 to 2. It was in the range of 5.

Solvent-based adhesive (DL): Manufactured by Rock Paint, two-component curable urethane-based solvent-based adhesive, main ingredient: RU-80, curing agent: H-5 = 10:1.15. The weight average molecular weight (Mw) of the polymer component contained in the base agent was in the range of 30,000 to 34,000, and the number average molecular weight (Mn) was in the range of 7,500 to 9,500.

[Preparation of each coating fluid]
Each coating liquid having the following composition was prepared.

(Coating liquid for white layer)
・Synthetic resin 12 parts by mass ・Titanium oxide 30 parts by mass ・Solvent 58 parts by mass

(EVOH-containing coating liquid)
・12 parts by mass of ethylene-vinyl alcohol copolymer (EVOH, manufactured by Mitsubishi Chemical, SoarnoL 16DX)
・Water 44 parts by mass ・Isopropyl alcohol (IPA) 44 parts by mass

(PVA-containing coating liquid)
・Polyvinyl alcohol 20 parts by mass (PVA, manufactured by Kuraray, Poval 3-88)
・Water 40 parts by mass ・IPA 40 parts by mass

(Anchor coating agent)
・Isocyanate 10 parts by mass (Mitsui Chemicals, Takenate A-3)
・Ethyl acetate 90 parts by mass

[Preparation of laminate]
In the following descriptions of Examples and Comparative Examples, detailed explanations of the contents already explained regarding the already mentioned layers (for example, layer formation conditions and thickness) may be omitted as appropriate.

[Example 1]
A solvent-free adhesive is applied to the corona-treated surface of the EVOH-containing substrate (A) to form an adhesive layer with a thickness of 1.0 μm, and the adhesive layer surface is connected to the corona-treated surface of the PE film (A). Pasted together. After bonding, aging treatment was performed at 40° C. for 4 days. A laminate was produced as described above.

[Example 2]
A white layer coating solution was applied to the corona-treated surface of the EVOH-containing substrate (A) using a gravure printing machine and dried with hot air to form a 1.0 μm thick white layer. A solvent-free adhesive was applied to the white layer surface of the base material to form an adhesive layer with a thickness of 1.0 μm, and the adhesive layer surface was bonded to the corona-treated surface of the PE film (A). After bonding, aging treatment was performed at 40° C. for 4 days. A laminate was produced as described above.

[Examples 3 to 8]
A laminate was produced in the same manner as in Example 1 or 2, except that the EVOH-containing base material or Ny-containing base material listed in Table 2 was used instead of the EVOH-containing base material (A).

[Example 9]
An EVOH-containing coating liquid was applied to the corona-treated surface of the PE base material using a gravure printing machine and dried with hot air to form an EVOH coating layer with a thickness of 1.0 μm. A solvent-free adhesive was applied to the EVOH coat layer surface of the PE base material to form an adhesive layer with a thickness of 1.0 μm, and the adhesive layer surface was bonded to the corona-treated surface of the PE film (A). After bonding, aging treatment was performed at 40° C. for 4 days. A laminate was produced as described above.

[Examples 10 and 11]
A laminate was produced in the same manner as in Example 9 except that a 1.0 μm thick white layer was further formed on the EVOH coat layer or the PE base material.

[Example 12 and 13]
A laminate of Example 12 was prepared in the same manner as in Example 1, except that a solvent-based adhesive was applied instead of a solvent-free adhesive and dried with hot air to form an adhesive layer with a thickness of 3.0 μm. did. A laminate of Example 13 was prepared in the same manner as in Example 2, except that a solvent-based adhesive was applied instead of a solvent-free adhesive and dried with hot air to form an adhesive layer with a thickness of 3.0 μm. did.

[Example 14]
Corona treatment was performed on both sides of the PE substrate. The procedure was the same as in Example 9, except that an EVOH coat layer was formed on one side of the PE base material, and the corona-treated side of the PE film (A) was bonded to the other side via a solvent-free adhesive. A laminate was produced.

[Example 15]
Corona treatment was performed on both sides of the PE substrate. An EVOH coating layer was formed on one side of the PE base material, a white layer was formed on the other side, and the corona-treated side of the PE film (A) was further bonded with a solvent-free adhesive. A laminate was produced in the same manner as in Example 10 except for this.

[Example 16]
A laminate was produced in the same manner as in Example 4, except that "CXU-ELS" was used instead of PE film (A).

[Example 17]
Using a gravure printing machine, a PVA-containing coating liquid was applied to the corona-treated surface of the PE base material instead of an EVOH-containing coating liquid, and the coating liquid was dried with hot air to form a PVA coating layer with a thickness of 1.0 μm. A laminate was produced in the same manner as in Example 9 except for this.

[Example 18]
Corona treatment was performed on both sides of the PE substrate. A PVA coating layer was formed on one side of the PE base material, and the corona-treated side of the PE film (A) was bonded to the other side via a solvent-free adhesive. A laminate was produced.

[Example 19]
An anchor coat agent was applied to the corona-treated surface of the PE base material using a gravure printing machine and dried with hot air to form an anchor coat layer (AC layer) with a thickness of 0.5 μm. An EVOH-containing coating liquid was applied to the AC layer surface of the PE base material using a gravure printer and dried with hot air to form an EVOH coat layer with a thickness of 1.0 μm. A solvent-free adhesive was applied to the EVOH coat layer surface of the PE base material to form an adhesive layer with a thickness of 1.0 μm, and the adhesive layer surface was bonded to the corona-treated surface of the PE film (A). After bonding, aging treatment was performed at 40° C. for 4 days. A laminate was produced as described above.

[Example 20]
A laminate was produced in the same manner as in Example 19 except that a white layer was further formed on the EVOH coat layer.

[Example 21]
Corona treatment was performed on both sides of the PE substrate. Example except that an AC layer and an EVOH coat layer were sequentially formed on one side of the PE base material, and the corona-treated side of the PE film (A) was bonded to the other side via a solvent-free adhesive. A laminate was produced in the same manner as in Example 19.

[Example 22]
Corona treatment was performed on both sides of the PE substrate. An AC layer and an EVOH coat layer are sequentially formed on one side of the PE base material, a white layer is formed on the other side, and the corona-treated side of the PE film (A) is further bonded with a solvent-free adhesive. A laminate was produced in the same manner as in Example 20 except that they were bonded together.

[Example 23]
A laminate was produced in the same manner as in Example 17 except that a PVA coat layer was formed on the PE base material via an AC layer.

[Example 24]
Corona treatment was performed on both sides of the PE substrate. Example except that an AC layer and a PVA coat layer were sequentially formed on one side of the PE base material, and the corona-treated side of the PE film (A) was bonded to the other side via a solvent-free adhesive. A laminate was produced in the same manner as in Example 23.

[Example 25]
An anchor coating agent was applied to the corona-treated surface of the PP base material using a gravure printing machine and dried with hot air to form an AC layer with a thickness of 0.5 μm. An EVOH-containing coating liquid was applied to the AC layer surface of the PP base material using a gravure printing machine and dried with hot air to form an EVOH coat layer with a thickness of 1.0 μm. A white layer coating liquid was applied to the EVOH coat layer surface of the PP base material using a gravure printer and dried with hot air to form a 1.0 μm thick white layer. A solvent-free adhesive was applied to the white layer surface of the PP base material to form an adhesive layer with a thickness of 1.0 μm, and the adhesive layer surface was bonded to the corona-treated surface of the PP film. After bonding, aging treatment was performed at 40° C. for 4 days. A laminate was produced as described above.

[Comparative Examples 1 and 2]
A solvent-based adhesive is applied to the corona-treated surface of the PE base material or Ny base material and dried with hot air to form an adhesive layer with a thickness of 3.0 μm, and the adhesive layer surface is subjected to the corona treatment of the PE film (A). Attached to the surface. After bonding, aging treatment was performed at 40° C. for 4 days. A laminate was produced as described above.

[Example 1A]
A white layer coating solution was applied to the corona-treated surface of the PE base material using a gravure printing machine and dried with hot air to form a 1.0 μm thick white layer. A solvent-free adhesive was applied to the white layer surface of the base material to form an adhesive layer with a thickness of 1.0 μm, and the adhesive layer surface was bonded to the corona-treated surface of the PE film (A). After bonding, aging treatment was performed at 40° C. for 4 days. A laminate was produced as described above.

[Examples 2A to 4A]
Using a gravure printing machine on the corona-treated surface of the PE base material,
- In Example 2A, an oil-based gravure ink (manufactured by DIC Graphics, trade name: Finart) was applied and dried with hot air to form a printing layer, and a white layer coating liquid was applied on top of that and dried with hot air to form a white layer. form;
- In Example 3A, the above oil-based gravure ink is applied and dried with hot air to form a printing layer, the coating liquid for white layer is applied on top of that and dried with hot air to form a white layer, and the above oil-based gravure ink is applied on top of that and the white layer is formed by drying with hot air. Applying ink and drying with hot air to form a printing layer;
- In Example 4A, a white layer coating solution was applied and dried with hot air to form a white layer, and the oil-based gravure ink was applied thereon and dried with hot air to form a printed layer.
The thickness of each layer is 1.0 μm.

A solvent-free adhesive is applied to the white layer surface or printed layer surface of the PE base material to form an adhesive layer with a thickness of 1.0 μm, and the adhesive layer surface is bonded to the corona-treated surface of the PE film (A). Ta. After bonding, aging treatment was performed at 40° C. for 4 days.
A laminate was produced as described above.

[Comparative Examples 1A and 2A]
A solvent-based adhesive is applied to the corona-treated surface of the PE base material or Ny base material and dried with hot air to form an adhesive layer with a thickness of 3.0 μm, and the adhesive layer surface is subjected to the corona treatment of the PE film (A). Attached to the surface. After bonding, aging treatment was performed at 40° C. for 4 days. A laminate was produced as described above.

[Preparation of packaging bag]
Two of the obtained laminates were prepared, the laminates were stacked on top of each other so that the sealant layers faced each other, and two sides were heat-sealed to form a body. Next, yet another laminate was folded into a V-shape with the sealant layer on the outside, sandwiched from one end of the body, and heat-sealed to form a bottom, thereby creating a standing pouch. The heat sealing conditions were a temperature of 140° C. (other than Example 25) or 180° C. (Example 25), a pressure of 1 kgf/cm ² , and a time of 1 second.

[Tear strength]
In accordance with JIS P8116:2000 and JIS K7128-2:1998, the laminates produced in Examples and Comparative Examples were cut into a size of 63 mm x 76 mm to produce test pieces. Here, the laminate was cut so that the short sides of the 63 mm length were aligned in the longitudinal direction (MD), transverse direction (TD), or diagonal direction of 45° with respect to the MD. At the center of the long side of the test piece, from the base material side of the laminate, along the short side of the test piece, the output is 80% of the (average) output of each device and the scanning speed is 100 mm/s or 1000 mm/s. A straight easy-to-cut line (easy-to-open line) was formed by irradiating the laser with a laser. Five easy-to-open lines were formed (see FIG. 12). The interval between the easy-to-open lines was 4 mm.

The following laser irradiation device was used.
・CO ₂ laser irradiation device (manufactured by Keyence, 3-Axis CO ₂ laser marker ML-Z9520, CO ₂ laser, wavelength 10.6 μm, average output 30 W),
・Fiber laser irradiation device (Manufactured by Panasonic, LP-Z250,
Yb: fiber laser, wavelength 1060 nm, average output 25 W,
Print pulse period 10μs, line width 70μm)
・UV laser irradiation device (Keyence, 3-Axis UV laser marker MD-U1000C, YVO ₄ laser, wavelength 355 nm, output 2.5 W)

The tear strength along the easy tear line was measured in accordance with the Elmendorf tear method of JIS K7128-2:1998. The measuring device used was an Elmendorf tear tester (Toyo Seiki Seisakusho S-01). A test piece is made by stacking four laminates, two test pieces are measured, the result is multiplied by 4, the value is converted to a value for each 16 pieces, and the average value of the obtained values is determined as the tear strength (N ). The evaluation when the easy-to-open line was not formed in the laminate of Example 1A was described as Reference Example 1A.

[Hand-tearability evaluation (Examples 1 to 25 and Comparative Examples 1 to 2)]
The hand tearability of the laminate was evaluated based on the above tear strength.
AA: Less than 1.0N A: 1.0N or more and less than 1.3N B: 1.3N or more and less than 1.7N C: 1.7N or more and less than 3.0N D: 3.0N or more E: OVER (unmeasurable)

[Hand tearability evaluation (Examples 1A to 4A and Comparative Examples 1A to 2A)]
The hand tearability of the laminate was evaluated based on the above tear strength.
A: Less than 3.0N B: 3.0N or more C: OVER (cannot be measured)

[Monomaterial rate]
A case where the content rate of polyethylene in the laminate was 90% by mass or more was evaluated as "A", and a case where the content rate of polyethylene in the laminate was less than 90% by mass was evaluated as "B".

[Observation of cross section of altered part and measurement of width W1]
Points P1, P2, and P3 were set at the boundaries when the easy-open line formed along the short side of the test piece was divided into four. The laminate was cut along a straight line that was perpendicular to the direction in which the easy-to-open line extended and also passed through points P1, P2, and P3. Three cut surfaces were observed and the width of the altered area was measured. The average value of the three width measurements was used as the width W1 of the altered portion. In the table, the width W1 is described as "line width".
Using a digital microscope VHX-6000 manufactured by Keyence Corporation, (A) Example 2 (CO ₂ laser irradiation, output: 80%, scanning speed: 1000 mm/sec), (B) Example 2 (fiber laser irradiation, Output: 80%, scanning speed: 100 mm/sec), (C) The cross-sectional shape of the laminate of Example 2 (UV laser irradiation, output: 80%, scanning speed: 100 mm/sec) was observed (observation magnification: 1000 times) ). The observation results of each laminate are shown in FIGS. 13(A) to 13(C). Each is an image of a cross section perpendicular to the MD direction of a laminate irradiated with laser along the MD direction.

Using the length measurement function of VHX-6000, the width W1 of the altered portion shown in FIGS. 13(A) to (C) was measured. The results were 121 μm, 122 μm, and 104 μm in (A), (B), and (C), respectively.

The cross-sectional shape of the laminate of Example 1A (CO ₂ laser irradiation, output: 80%, scanning speed: 1000 mm/sec) was observed using a digital microscope VHX-6000 manufactured by Keyence Corporation (observation magnification: 1000 times). . The observation results of the laminate are shown in FIG. 14. FIG. 14 is an image of a cross section perpendicular to the MD direction of the laminate irradiated with laser along the MD direction. Using the length measurement function of VHX-6000, the width W1 of the altered portion shown in FIG. 14 was measured. As a result, it was 109 μm.

As those skilled in the art will understand, the laminate etc. of the present disclosure are not limited by the description of the above embodiments, and the above embodiments and specification are merely for illustrating the principles of the present disclosure. Various modifications or improvements can be made without departing from the spirit and scope of the invention, and all such modifications or improvements are included within the scope of the claimed disclosure. Furthermore, the scope of this disclosure includes not only the claims but also equivalents thereof.

10 Packaging bag 11 Upper part 12 Lower part 12a Lower seal part 13 Side part 13a Side seal part 14 Front film 15 Back film 16 Lower film 17 Storage part 20 Spout part 20a Spout seal part 26 Easy-open line 27 Through hole 28 Notch 30 Laminate 30x Inner surface 30y Outer surface 40 Stretched base material 42 Polyolefin layer 44 Adhesive resin layer 46 Exothermic resin layer 50 Exothermic resin layer or exothermic layer 60 Adhesive layer 70 Sealant layer 80 Exothermic layer

Claims

A laminate comprising at least a stretched base material and a sealant layer,
The stretched base material includes at least a polyolefin layer,
The sealant layer contains polyolefin as a main component,
The laminate includes a heat-generating resin layer containing as a main component a heteroatom-containing resin that generates heat by absorbing laser, and the heat-generating resin layer is arranged between the stretched base material and the sealant layer in the stretched base material. and at least one location on the surface of the stretched base material opposite to the surface on the side of the sealant layer,
laminate.
The laminate according to claim 1, wherein the heteroatom-containing resin contains at least one selected from ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and polyamide.
The laminate according to claim 1 or 2, wherein the stretched base material includes at least the polyolefin layer, the adhesive resin layer, and the exothermic resin layer.
The laminate according to any one of claims 1 to 3, wherein the laminate includes at least the stretched base material including the heat-generating resin layer, an adhesive layer, and the sealant layer in this order.
The laminate according to any one of claims 1 to 3, wherein the laminate comprises at least the stretched base material, the exothermic resin layer, the adhesive layer, and the sealant layer in this order.
The laminate according to any one of claims 1 to 3, wherein the laminate comprises at least the exothermic resin layer, the stretched base material, the adhesive layer, and the sealant layer in this order.
Any one of claims 1 to 6, wherein the laminate further comprises a heat generating layer containing a heat generating substance that absorbs laser and generates heat (excluding the heteroatom-containing resin that generates heat by absorbing laser). The laminate described in section.
The laminate according to claim 7, wherein the exothermic substance is at least one selected from metal oxides, bismuth-based compounds, molybdenum, molybdenum-based compounds, copper, copper-based compounds, and carbon black.
The polyolefin layer of the stretched base material is a polyethylene layer, and the sealant layer contains polyethylene as a main component, or
The polyolefin layer of the stretched base material is a polypropylene layer, and the sealant layer contains polypropylene as a main component.
The laminate according to any one of claims 1 to 8.
The sealant layer is
comprising at least a first layer and a second layer,
The first layer contains an ethylene/α-olefin copolymer as a main component,
The melting point of the first layer is 112°C or less,
The second layer contains polyethylene as a main component,
The second layer has a melting point of 114° C. or higher,
one surface layer of the laminate is the first layer,
The laminate according to any one of claims 1 to 9.
The density of the first layer is 0.915 g/cm 3 or less,
The density of the second layer is 0.916 g/cm 3 or more,
The laminate according to claim 10.
The laminate according to any one of claims 1 to 11, wherein the polyolefin content in the entire laminate is 80% by mass or more.
A laminate comprising at least a stretched base material and a sealant layer,
The stretched base material contains polyethylene as a main component,
The sealant layer is
comprising at least a first layer and a second layer,
The first layer contains an ethylene/α-olefin copolymer as a main component,
The melting point of the first layer is 112°C or less,
The second layer contains polyethylene as a main component,
The second layer has a melting point of 114° C. or higher,
One surface layer of the laminate is the first layer,
The laminate further includes a heat generating layer containing a heat generating substance that absorbs laser and generates heat between the stretched base material and the sealant layer.
laminate.
The density of the first layer is 0.915 g/cm 3 or less,
The density of the second layer is 0.916 g/cm 3 or more,
The laminate according to claim 13.
The laminate according to claim 13 or 14, wherein the exothermic substance is at least one selected from metal oxides, bismuth-based compounds, molybdenum, molybdenum-based compounds, copper, copper-based compounds, and carbon black.
The laminate according to any one of claims 13 to 15, wherein the exothermic substance is a metal oxide.
The laminate according to any one of claims 13 to 16, wherein the heat generating layer is a printed layer provided on the stretched base material.
The laminate according to any one of claims 13 to 17, further comprising an adhesive layer between the heat generating layer and the sealant layer.
The laminate according to any one of claims 13 to 18, wherein the content of polyethylene in the entire laminate is 80% by mass or more.
A packaging bag comprising the laminate according to any one of claims 1 to 19,
The packaging bag is
a storage section that accommodates the contents;
a sealing portion in which the sealant layers of the laminate are joined;
and an easy-to-open line including the altered portion of the laminate;
The seal portion includes an inner edge defining the housing portion,
The easy-to-open line includes a first intersection point and a second intersection point that intersect the inner edge of the seal portion, and is a line that crosses the storage portion when the packaging bag is viewed from above.
packaging bag.