Laminate, packaging material, packaging body and packaging article

Abstract

The present invention provides a laminate having excellent resistance to abuse and adhesion, and a packaging material, a package, and a packaged article each including the laminate. The laminate 10 includes, in this order, a first base material layer 1, an anchor coat layer 2, and an inorganic barrier layer 3. The first base material layer 1 includes a polyolefin, and the anchor coat layer 2 has a cross-sectional composite elastic modulus in the range of 3.5 to 6.5 GPa and a thickness in the range of 0.4 to 3.0 μm.

Description

[Technical field]

[0001] The present invention relates to a laminate, a packaging material, a package and a packaged article. [Background technology]

[0002] Packaging materials for long-term storage of foods, beverages, medicines, etc. are required to have gas barrier properties that prevent oxygen, water vapor, and other gases that may deteriorate the contents from entering the package. Meanwhile, in recent years, there has also been a demand for high recyclability in packaging materials, and the movement to switch from conventional packaging materials to highly recyclable all-polyolefin mono-material packages is progressing not only in Japan but also worldwide.

[0003] Various types of gas barrier films for use in packaging materials have been developed, including, for example, vapor-deposited films in which an inorganic coating layer of silicon oxide, aluminum oxide, or the like is formed as a gas barrier layer on a polymer film by vacuum deposition or sputtering. Such gas barrier films have a problem in that when a polyolefin layer is used as the polymer layer, the gas barrier properties are lower than those of a polyester layer such as polyethylene terephthalate. Another problem is that the adhesion between the polymer film and the inorganic coating layer is insufficient.

[0004] In order to improve the gas barrier properties of the above-mentioned vapor-deposited film, a technique has been proposed in which a third layer made of a resin material is provided between the polymer film and the inorganic coating layer as a planarizing layer, an adhesive layer, or the like (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2022 / 056095 [Patent Document 2] International Publication No. 2022 / 220200 Summary of the Invention

[0006] Particularly high performance is required for packaging materials that are subjected to high temperature and pressure or high temperature and humidity environments such as retort treatment or boiling treatment. That is, gas barrier films used in such packaging materials are required to have excellent abuse resistance that allows them to maintain a high level of gas barrier properties even when subjected to physical stress such as bending after severe treatment such as retort treatment. In addition, such gas barrier films are also required to have excellent adhesion that allows them to maintain high interlayer adhesive strength even after severe treatment such as retort treatment.

[0007] An object of the present invention is to provide a laminate having excellent resistance to abuse and adhesion, and a packaging material, a package, and a packaged article each containing the laminate.

[0008] According to one aspect of the present invention, there is provided a laminate comprising, in this order, a first substrate layer, an anchor coat layer, and an inorganic barrier layer, wherein the first substrate layer comprises a polyolefin, and the anchor coat layer has a cross-sectional composite elastic modulus in the range of 3.5 to 6.5 GPa and a thickness in the range of 0.4 to 3.0 μm.

[0009] According to another aspect of the present invention, there is provided a laminate relating to the above aspect, wherein the first substrate layer has a layer structure including a skin layer in contact with the anchor coat layer and a core layer, the anchor coat layer has a cross-sectional hardness in the range of 200 MPa or more and 350 MPa or less, and the skin layer has a cross-sectional hardness of 150 MPa or less.

[0010] According to yet another aspect of the present invention, there is provided the laminate according to the above aspect, wherein the skin layer has a cross-sectional hardness of 20 MPa or more.

[0011] According to yet another aspect of the present invention there is provided a laminate according to any of the above aspects, wherein the thickness of the skin layer is in the range of 0.2 to 1.8 μm.

[0012] According to yet another aspect of the present invention, there is provided a laminate according to any of the above aspects, wherein the anchor coat layer is a cured film of an anchor coat agent containing a polyurethane resin and a curing agent, and the solid mass ratio of the polyurethane resin to the curing agent in the anchor coat agent [curing agent / polyurethane resin] is within a range of 30 / 100 to 50 / 100.

[0013] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, wherein the inorganic barrier layer contains silicon oxide or aluminum oxide.

[0014] According to yet another aspect of the present invention there is provided a packaging material comprising a laminate according to any of the above aspects.

[0015] According to yet another aspect of the present invention, there is provided a packaging material related to the above aspect, comprising a sealant layer formed on a surface of the laminate facing the first base material layer via a first adhesive layer, and a second base material layer formed on a surface of the laminate facing the inorganic barrier layer via a second adhesive layer.

[0016] According to yet another aspect of the present invention, there is provided a packaging material according to any of the above aspects for use in a retort pouch.

[0017] According to yet another aspect of the present invention there is provided a package comprising a packaging material according to any of the above aspects.

[0018] According to yet another aspect of the present invention, there is provided a packaged article including the package according to the above aspect and contents contained therein.

[0019] According to the present invention, there are provided a laminate having excellent resistance to abuse and adhesion, and a packaging material, a package, and a packaged article each containing the laminate. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a partial cross-sectional view illustrating an example of a laminate according to a first embodiment of the present invention. [Diagram 2]FIG. 4 is a partial cross-sectional view illustrating a laminate according to a modified example of the first embodiment. [Diagram 3] FIG. 5 is a partial cross-sectional view illustrating an example of a packaging material according to a second embodiment of the present invention. [Figure 4] FIG. 11 is a partial cross-sectional view illustrating a packaging material according to a modified example of the second embodiment. [Diagram 5] 1A-1C are cross-sectional views each showing a schematic diagram of a step in the measurement of composite modulus and hardness. [Figure 6] Graph showing a load-displacement curve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0022] The embodiments described below are merely examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited by the materials, shapes, structures, etc. of the components described below. Various modifications can be made to the technical idea of ​​the present invention within the technical scope defined by the claims.

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

[0024] [First embodiment] Fig. 1 is a partial cross-sectional view that shows a schematic example of a laminate according to a first embodiment of the present invention. The laminate 10 shown in Fig. 1 includes, in this order, a first base material layer 1, an anchor coat layer 2, and an inorganic barrier layer 3. Each layer included in the laminate 10 will be described below.

[0025] (1st base layer) The first base layer 1 is a film that serves as one of the supports, and may be a single layer or a laminate structure including two or more layers.

[0026] The first base layer 1 contains polyolefin. The first base layer 1 may be made of a polyolefin film. Examples of polyolefin films include polyethylene film (PE), polypropylene film (PP), and polybutene film (PB). The polyolefin film may be an acid-modified polyolefin film obtained by graft-modifying a polyolefin with an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like.

[0027] The polyolefin film constituting the first base layer 1 may be a stretched film or a non-stretched film. From the viewpoints of impact resistance, heat resistance, water resistance, dimensional stability, etc., the polyolefin film may be a stretched film. This makes it possible to make the laminate 10 more suitable for applications in which it is subjected to high temperature and high pressure or high temperature and high humidity environments such as retort processing and boiling processing. The stretching method is not particularly limited. The stretching method may be any method such as stretching by inflation, uniaxial stretching, biaxial stretching, etc., as long as a film with stable dimensions can be supplied.

[0028] The thickness of the first base layer 1 is not particularly limited and can be appropriately set depending on the application within a range of, for example, 6 to 200 μm. According to one example, the thickness of the first base layer 1 may be within a range of 9 to 50 μm, or may be within a range of 12 to 38 μm, from the viewpoint of obtaining excellent impact resistance and excellent gas barrier properties.

[0029] The first base layer 1 may be subjected to various pretreatments such as corona treatment, plasma treatment, and frame treatment on the main surface on which the anchor coat layer 2 is formed, as long as the barrier performance is not impaired, and a coating layer such as an easy-adhesion layer may also be provided.

[0030] (Anchor coat layer) The laminate 10 includes an anchor coat layer 2 between a first base layer 1 and an inorganic barrier layer 3. The anchor coat layer 2 has a cross-sectional composite elastic modulus in the range of 3.5 to 6.5 GPa at room temperature (25°C) and a thickness in the range of 0.4 to 3.0 µm. As described below, the anchor coat layer 2 imparts excellent abuse resistance and adhesion to the laminate 10. Here, abuse resistance refers to a property that can suppress a decrease in at least one of the oxygen barrier property and the water vapor barrier property even when a Gelbo flex test (a test in which a gas barrier film is repeatedly compressed while being twisted) is performed.

[0031] In the anchor coat layer 2, the composite elastic modulus of the cross section is 6.5 GPa or less, which contributes to improving the abuse resistance of the laminate 10. By setting the composite elastic modulus to 6.5 GPa or less, the anchor coat layer 2 becomes flexible, and the inorganic barrier layer 3 is less likely to crack when physical stress such as bending is applied to the laminate 10. In this case, the thickness of the anchor coat layer 2 is within the range of 0.4 to 3.0 μm. If the thickness of the anchor coat layer 2 is excessively large, the abuse resistance decreases, and even if the composite elastic modulus of the cross section is 6.5 GPa or less, the desired abuse resistance cannot be obtained. In addition, if the thickness of the anchor coat layer 2 is excessively small, the influence of the contraction of the first base layer 1 is transmitted to the inorganic barrier layer 3 during treatment such as retort, and the gas barrier property decreases. Therefore, if the thickness of the anchor coat layer 2 is less than 0.4 μm, the gas barrier properties will decrease after treatment in a high temperature and high pressure or high temperature and high humidity environment such as retort treatment, and even if the cross-sectional composite elastic modulus of the anchor coat layer 2 is 6.5 GPa or less, the desired gas barrier properties and abuse resistance will not be obtained.

[0032] In the anchor coat layer 2, the cross-sectional composite elastic modulus of 3.5 GPa or more contributes to improving the adhesion of the laminate 10. By setting this composite elastic modulus to 3.5 GPa or more, the adhesion of the laminate 10 is improved, and delamination between the anchor coat layer 2 and the inorganic barrier layer 3 is unlikely to occur even after treatment in a high temperature and high pressure or high temperature and high humidity environment such as retort treatment. In this case, the thickness of the anchor coat layer is 3.0 μm or less. If the thickness of the anchor coat layer 2 is excessively large, the adhesion decreases, and even if the composite elastic modulus is 3.5 GPa or more, the desired adhesion cannot be obtained.

[0033] In this way, by setting the thickness of the anchor coat layer 2 within the range of 0.4 to 3.0 μm and the composite elastic modulus of the cross section within the range of 3.5 to 6.5 GPa, excellent abuse resistance and adhesion are imparted to the laminate 10. Since the laminate 10 having the anchor coat layer 2 has excellent abuse resistance and adhesion, it can maintain good gas barrier properties and high interlayer adhesive strength even when subjected to physical stress such as bending after treatment in a harsh environment such as retort treatment. This composite elastic modulus is measured using a nanoindentation method, and will be described later with reference to the drawings.

[0034] The anchor coat layer 2 preferably has a cross-sectional composite elastic modulus in the range of 4.0 to 6.0 GPa at room temperature (25° C.). The anchor coat layer 2 preferably has a thickness in the range of 0.5 to 3.0 μm, more preferably in the range of 0.7 to 2.0 μm. The anchor coat layer 2 also functions as a planarizing layer, and allows the inorganic barrier layer 3 to be formed uniformly without defects, thereby further improving the gas barrier properties of the laminate 10.

[0035] The anchor coat layer 2 can be formed by using an anchor coat agent. Examples of the anchor coat agent include polyester-based polyurethane resin, polyether-based polyurethane resin, and water-dispersed polyurethane resin.

[0036] The anchor coating agent contains, for example, a polyurethane resin and a curing agent, which will be described below. <Polyurethane resin> The polyurethane resin may be a reaction product between a polyurethane resin having an acid group (hereinafter also referred to as an "acid group-containing polyurethane resin") and a polyamine compound. That is, the polyurethane resin may be obtained by bonding the acid group of the acid group-containing polyurethane with the amino group of the polyamine compound. The bond between the acid group of the acid group-containing polyurethane resin and the amino group of the polyamine compound may be an ionic bond (e.g., an ionic bond between a carboxyl group and a tertiary amino group) or a covalent bond (e.g., an amide bond).

[0037] The acid group-containing polyurethane constituting the polyurethane resin has anionic properties and self-emulsifying properties due to the presence of acid groups, and is also called anionic self-emulsifying polyurethane. The acid group of the acid group-containing polyurethane can be bonded to the amino group (primary amino group, secondary amino group, tertiary amino group, etc.) of the polyamine constituting the polyurethane resin. Examples of the acid group include a carboxyl group and a sulfonic acid group. The acid group can usually be neutralized by a neutralizing agent (base), and may form a salt with a base. The acid group may be located at the end or side chain of the acid group-containing polyurethane, but is preferably located at least on the side chain.

[0038] The acid value of the acid group-containing polyurethane can be selected within a range in which the acid group-containing polyurethane is water-dispersible, and can be 5 to 100 mgKOH / g, or may be 10 to 70 mgKOH / g, or may be 15 to 60 mgKOH / g. When the acid value of the acid group-containing polyurethane is equal to or greater than the lower limit of the above range, the water dispersibility of the acid group-containing polyurethane is easily obtained, and the uniform dispersion of the polyurethane resin and other materials and the dispersion stability of the anchor coating agent are easily ensured. When the acid value of the acid group-containing polyurethane is equal to or less than the upper limit of the above range, the water resistance and gas barrier properties of the undercoat layer are easily ensured. The acid value of the acid group-containing polyurethane is measured by a method in accordance with JIS K 0070.

[0039] The total of the urethane group concentration and the urea group concentration of the acid group-containing polyurethane can be 15% by mass or more, and may be 20 to 60% by mass, from the viewpoint of gas barrier properties. When the total of the urethane group concentration and the urea group concentration is equal to or more than the lower limit, the gas barrier properties of the undercoat layer tend to be good. When the total of the urethane group concentration and the urea group concentration is equal to or less than the upper limit of the above range, the undercoat layer tends to be prevented from becoming rigid and brittle.

[0040] The urethane group concentration means the ratio of the molecular weight of the urethane group (59 g / equivalent) to the molecular weight of the constituent unit of the polyurethane resin. The urea group concentration means the ratio of the molecular weight of the urea group (primary amino group (amino group): 58 g / equivalent, secondary amino group (imino group): 57 g / equivalent) to the molecular weight of the constituent unit of the polyurethane resin. When a mixture of two or more types of acid group-containing polyurethane is used, the urethane group concentration and the urea group concentration can be calculated based on the charged base of the reaction components, that is, based on the use ratio of each component.

[0041] The acid group-containing polyurethane may have at least a rigid unit (a unit composed of a hydrocarbon ring) and a short-chain unit (for example, a unit composed of a hydrocarbon chain). The constituent unit of the acid group-containing polyurethane may contain a hydrocarbon ring (at least one of an aromatic and a non-aromatic hydrocarbon ring) derived from a polyisocyanate component, a polyhydroxy acid component, a polyol component, or a chain extender component (particularly, at least a polyisocyanate component). From the viewpoint of improving oxygen barrier properties, the polyurethane resin may contain an aromatic ring, and therefore, the constituent unit of the acid group-containing polyurethane may contain an aromatic hydrocarbon ring as a hydrocarbon ring.

[0042] The ratio of units composed of hydrocarbon rings in the structural units of the acid group-containing polyurethane can be 10 to 70 mass%, or may be 15 to 65 mass%, or may be 20 to 60 mass%, based on the total of all structural units. When the ratio of units composed of hydrocarbon rings is equal to or greater than the lower limit of the above range, the gas barrier properties of the undercoat layer are likely to be good. When the ratio of units composed of hydrocarbon rings is equal to or less than the upper limit of the above range, the undercoat layer is likely to be prevented from becoming rigid and brittle.

[0043] The number average molecular weight of the acid group-containing polyurethane can be appropriately selected, but can be 800 to 1,000,000, or may be 800 to 200,000, or may be 800 to 100,000. When the number average molecular weight of the acid group-containing polyurethane is equal to or less than the upper limit of the above range, the anchor coating agent is likely to have a suitable viscosity. When the number average molecular weight of the acid group-containing polyurethane is equal to or more than the lower limit of the above range, the gas barrier property of the undercoat layer is likely to be good. The number average molecular weight of the acid group-containing polyurethane is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0044] The acid group-containing polyurethane may be crystalline in order to enhance the gas barrier property. The glass transition temperature of the acid group-containing polyurethane may be 100°C or higher, may be 110°C or higher, or may be 120°C or higher. When the glass transition temperature of the acid group-containing polyurethane is 100°C or higher, the gas barrier property of the undercoat layer is likely to be good. The glass transition temperature of the acid group-containing polyurethane may be 200°C or lower, may be 180°C or lower, or may be 150°C or lower. Therefore, the glass transition temperature of the acid group-containing polyurethane may be 100 to 200°C, may be 110 to 180°C, or may be 120 to 150°C. The glass transition temperature of the acid group-containing polyurethane is measured by differential scanning calorimetry (DSC).

[0045] The polyamine constituting the polyurethane resin is a compound having two or more basic nitrogen atoms. The basic nitrogen atom is a nitrogen atom that can be bonded to the acid group of the acid group-containing polyurethane, and examples thereof include nitrogen atoms in amino groups such as primary amino groups, secondary amino groups, and tertiary amino groups. The polyamine is not particularly limited as long as it can be bonded to the acid group of the acid group-containing polyurethane and improve the gas barrier property, and various compounds having two or more basic nitrogen atoms can be used. The polyamine can be a polyamine having two or more amino groups of at least one type selected from the group consisting of primary amino groups, secondary amino groups, and tertiary amino groups.

[0046] Examples of polyamines include alkylenediamines, polyalkylenepolyamines, and silicon compounds having multiple basic nitrogen atoms. Examples of alkylenediamines include alkylenediamines having 2 to 10 carbon atoms, such as ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,4-butanediamine, and 1,6-hexamethylenediamine. Examples of polyalkylenepolyamines include tetraalkylenepolyamine. Examples of silicon compounds having multiple basic nitrogen atoms (including nitrogen atoms such as amino groups) include silane coupling agents having multiple basic nitrogen atoms, such as 2-[N-(2-aminoethyl)amino]ethyltrimethoxysilane and 3-[N-(2-aminoethyl)amino]propyltriethoxysilane.

[0047] The amine value of the polyamine can be 100 to 1900 mgKOH / g, may be 150 to 1900 mgKOH / g, may be 200 to 1900 mgKOH / g, may be 200 to 1700 mgKOH / g, or may be 300 to 1500 mgKOH / g. If the amine value of the polyamine is equal to or higher than the lower limit of the above range, the gas barrier properties of the undercoat layer tend to be good. If the amine value of the polyamine is equal to or lower than the upper limit of the above range, the aqueous dispersion stability of the polyurethane resin tends to be good.

[0048] [Method of measuring amine value] The amine value of the polyamine is measured by the following method. Accurately weigh out 0.5 to 2 g of sample (sample weight Sg). Add 30 g of ethanol to the weighed sample to dissolve it. Add bromophenol blue as an indicator to the resulting solution and titrate with 0.2 mol / L ethanolic hydrochloric acid solution (titer f). The endpoint is when the solution changes color from green to yellow, and the titer (AmL) at this point is used to calculate the amine value using the following formula 1. Calculation formula 1: Amine value = A x f x 0.2 x 56.108 / S [mgKOH / g]

[0049] In forming the polyurethane resin, the molar ratio of the acid groups of the acid group-containing polyurethane to the basic nitrogen atoms of the polyamine (acid groups / basic nitrogen atoms) can be 10 / 1 to 0.1 / 1, and may be 5 / 1 to 0.2 / 1. When the acid group / basic nitrogen atom ratio is within the above range, the undercoat layer is likely to exhibit excellent oxygen barrier properties.

[0050] The polyurethane resin can be obtained in a state dispersed in an aqueous medium (in the form of an aqueous dispersion). That is, the polyurethane resin can be called an aqueous polyurethane resin. The aqueous medium can be water, a water-soluble or hydrophilic organic solvent, or a mixture thereof. The water-soluble or hydrophilic organic solvent can be, for example, alcohols such as methanol, ethanol, isopropanol, etc.; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; cellosolves; carbitols; nitriles such as acetonitrile, etc. The aqueous medium can be water or one containing water as a main component. The content of water in the aqueous medium can be 70% by mass or more, and may be 80% by mass or more. The aqueous medium may or may not contain a neutralizing agent (base) that neutralizes the acid group of the acid group-containing polyurethane.

[0051] In the aqueous dispersion of polyurethane resin, the average particle size of the dispersed particles (polyurethane resin particles) is not particularly limited and may be 20 to 500 nm, may be 25 to 300 nm, or may be 30 to 200 nm. When the average particle size of the dispersed particles is equal to or less than the upper limit of the above range, it is easy to ensure uniform dispersion of the dispersed particles and other materials and dispersion stability of the anchor coating agent, and the gas barrier property of the undercoat layer formed from the anchor coating agent is easy to be improved. The average particle size can be measured by diluting with water to a solid content concentration of 0.03 to 0.3 mass% and using a concentrated particle size analyzer (Otsuka Electronics Co., Ltd., FPAR-10).

[0052] The polyurethane resin may be a commercially available polyurethane resin, or may be a polyurethane resin produced by a known production method. As the aqueous dispersion of the polyurethane resin formed from the acid group-containing polyurethane and polyamine as described above, Takelac (registered trademark) WPB-341A (manufactured by Mitsui Chemicals, Inc.) may be mentioned.

[0053] The method for producing a polyurethane resin is not particularly limited, and examples thereof include ordinary techniques for making polyurethane resin aqueous, such as the acetone method and the prepolymer method. In the urethanization reaction, a urethanization catalyst, such as an amine catalyst, a tin catalyst, or a lead catalyst, may be used as necessary. For example, in an inert organic solvent, such as a ketone such as acetone, an ether such as tetrahydrofuran, or a nitrile such as acetonitrile, a polyisocyanate compound, a polyhydroxy acid, and, if necessary, at least one of a polyol component and a chain extender component, are reacted to prepare an acid group-containing polyurethane. More specifically, in an inert organic solvent (particularly, a hydrophilic or water-soluble organic solvent), a polyisocyanate compound, a polyhydroxy acid, and a polyol component are reacted to generate a prepolymer having an isocyanate group at the end, which is neutralized with a neutralizing agent and dissolved or dispersed in an aqueous medium, and then a chain extender component is added and reacted, and the organic solvent is removed to prepare an aqueous dispersion of an acid group-containing polyurethane. A polyurethane resin in the form of an aqueous dispersion can be prepared by adding a polyamine to the aqueous dispersion of the acid group-containing polyurethane thus obtained and heating it as necessary. When heating, the heating temperature can be 30 to 60°C.

[0054] <Hardening agent> The curing agent is reactive with the polyurethane resin described above. The curing agent is not particularly limited as long as it is reactive with the polyurethane resin in the anchor coating agent, but is preferably an isocyanate compound, a silane coupling agent, or an epoxy compound. Among these, isocyanate compounds are preferred in terms of adhesion to the first base layer 1.

[0055] The isocyanate compound can be any compound having an isocyanate group (-NCO) without any particular limitation. The isocyanate group reacts with the hydroxyl group of the polyurethane resin to form a strong bond. Therefore, by including an isocyanate compound in the anchor coating agent, it is possible to increase the cohesive strength of the coating film and improve the adhesive strength with the first base layer 1 and the inorganic barrier layer 3, thereby increasing the practical strength as a packaging material.

[0056] The isocyanate compound is preferably a polyisocyanate compound having at least two isocyanate groups in the molecule, and examples thereof include organic polyisocyanate compounds such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, naphthylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, hydrogenated toluene diisocyanate, and tetramethylene xylylene diisocyanate, and derivatives of these organic polyisocyanate compounds.

[0057] As the isocyanate compound, an isocyanate compound having dispersibility in water (water-dispersible isocyanate compound) is preferable. Examples of the water-dispersible isocyanate compound include (1) an isocyanate compound obtained by modifying a part of the isocyanate group of the above-mentioned organic polyisocyanate compound with a hydrophilic group such as polyethylene oxide, a carboxyl group or a sulfonic acid group to make it a self-emulsifying type, (2) an isocyanate compound obtained by forcibly emulsifying the above-mentioned organic polyisocyanate compound with a surfactant or the like to make it water-dispersible, (3) various prepolymers derived from the above-mentioned organic polyisocyanate compound, and (4) a compound obtained by blocking a part of the isocyanate group in the above-mentioned organic polyisocyanate with a blocking agent such as alcohols, phenols, oximes, mercaptans, amides, imides or lactams, so-called blocked polyisocyanate compounds, etc. These isocyanate compounds may be used alone or in combination of two or more.

[0058] As the isocyanate compound, a commercially available isocyanate compound or an isocyanate compound produced by a known production method may be used. For example, a commercially available product is Takenate (registered trademark) WD-725 (manufactured by Mitsui Chemicals, Inc.), which is a water-dispersible type of hexamethylene diisocyanate modified product.

[0059] The composite elastic modulus of the cross section of the anchor coat layer 2 can be adjusted, for example, by the solid mass ratio of the polyurethane resin and the curing agent contained in the anchor coat agent. The solid mass ratio of the curing agent to the urethane resin in the anchor coat agent [curing agent / polyurethane resin] is preferably within the range of 30 / 100 to 50 / 100. More preferably, it is in the range of 35 / 100 to 40 / 100.

[0060] The anchor coating agent may contain known additives such as antioxidants, weathering agents, heat stabilizers, lubricants, crystal nucleating agents, ultraviolet absorbers, plasticizers, antistatic agents, colorants, fillers, and surfactants, within the limits that do not impair the gas barrier properties, wear resistance, and adhesion.

[0061] A known coating method can be used as a method for coating the anchor coat layer 2 on the first base layer 1. Known coating methods include, for example, a method using a spray, a coater, a printer, or a brush, and an immersion method (dipping method). In addition, examples of the types of coaters and printers used in these methods and the coating methods thereof include gravure coaters such as direct gravure method, reverse gravure method, kiss reverse gravure method, and offset gravure method, reverse roll coaters, microgravure coaters, coaters combined with chamber doctor, air knife coaters, dip coaters, bar coaters, comma coaters, and die coaters.

[0062] (Inorganic barrier layer) The inorganic barrier layer 3 has gas barrier properties such as oxygen barrier properties and water vapor barrier properties. The inorganic barrier layer 3 preferably contains an inorganic oxide. By using an inorganic oxide layer as the inorganic barrier layer 3, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the laminate 10. Examples of inorganic oxides contained in the inorganic barrier layer 3 include aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. From the viewpoints of transparency and barrier properties, the inorganic oxide is preferably any one of aluminum oxide, silicon oxide, and magnesium oxide. Furthermore, from the viewpoint of excellent tensile stretchability during processing, it is preferable to contain silicon oxide as the inorganic oxide.

[0063] The O / Si ratio (mass ratio) of the inorganic barrier layer 3 is preferably 1.7 or more. By suppressing the content of metal Si by setting the O / Si ratio to 1.7 or more, good transparency is easily obtained. In addition, the O / Si ratio of the inorganic barrier layer 3 is preferably 2.0 or less. When the O / Si ratio is 2.0 or less, the crystallinity of SiO is high. When the crystallinity of SiO is high, the inorganic barrier layer 3 can be prevented from becoming too hard, and good tensile resistance can be obtained. This can suppress the occurrence of cracks in the inorganic barrier layer 3 when forming a second base layer 14 described later on the inorganic barrier layer 3. In addition, when the package is subjected to retort or boiling treatment, the polyolefin film constituting the package may shrink due to heat. However, if the O / Si ratio of the inorganic barrier layer 3 is 2.0 or less and has good tensile resistance, it can follow the shrinkage and suppress the deterioration of the gas barrier property. From the viewpoint of obtaining these effects more fully, the O / Si ratio of the inorganic barrier layer 3 is more preferably 1.75 to 1.9, and even more preferably 1.8 to 1.85.

[0064] The O / Si ratio of the inorganic barrier layer can be determined by X-ray photoelectron spectroscopy (XPS). For example, the measurement conditions are as follows: an X-ray photoelectron spectrometer (manufactured by JEOL Ltd., product name: JPS-90MXV) is used as the measurement device, non-monochromated MgKα (1253.6 eV) is used as the X-ray source, and the measurement can be performed with an X-ray output of 100 W (10 kV-10 mA). For quantitative analysis to determine the O / Si ratio, a relative sensitivity factor of 2.28 for O1s and 0.9 for Si2p can be used.

[0065] The thickness of the inorganic barrier layer 3 is preferably 10 nm to 80 nm, more preferably in the range of 15 nm to 60 nm. If the thickness is equal to or greater than the lower limit, sufficient barrier performance can be obtained. If the thickness is equal to or less than the upper limit, the occurrence of cracks due to deformation caused by internal stress in the thin film can be suppressed, and the deterioration of the barrier performance can be suppressed. If the thickness exceeds the upper limit, cracks are likely to occur due to deformation caused by internal stress, and the resistance to abuse is also reduced. If the thickness exceeds the upper limit, costs are likely to increase due to an increase in the amount of material used and a longer film formation time, which is also undesirable from an economic point of view.

[0066] The inorganic barrier layer 3 can be formed, for example, by vacuum film formation. In the vacuum film formation, physical vapor deposition or chemical vapor deposition can be used. Examples of physical vapor deposition include, but are not limited to, vacuum deposition, sputtering, and ion plating. Examples of chemical vapor deposition include, but are not limited to, thermal CVD, plasma CVD, and photo CVD.

[0067] In the vacuum film formation, resistance heating vacuum deposition, EB (Electron Beam) heating vacuum deposition, induction heating vacuum deposition, sputtering, reactive sputtering, dual magnetron sputtering, plasma enhanced chemical vapor deposition (PECVD), etc. are particularly preferably used. However, in terms of productivity, the vacuum deposition is currently the most superior. As a heating means for the vacuum deposition, it is preferable to use any of the electron beam heating method, resistance heating method, and induction heating method.

[0068] (Printing layer) The laminate 10 may further include a printing layer (not shown). The printing layer is provided at a position visible from the outside of the laminate 10 for the purpose of displaying information about the contents, identifying the contents, or improving the design of the package. For example, the printing layer may be interposed between the first base layer 1 and the anchor coat layer 2. The printing method and printing ink are not particularly limited, and are appropriately selected from known printing methods and printing inks in consideration of printability on the film, design such as color tone, adhesion, safety as a food container, and the like. Examples of printing methods that can be used include gravure printing, offset printing, gravure offset printing, flexographic printing, and inkjet printing. Among them, gravure printing can be preferably used from the viewpoints of productivity and high definition of the pattern.

[0069] In order to improve the adhesion of the printing layer, the surface of the first base layer 1 on the side of the anchor coat layer 2 may be subjected to various pretreatments such as corona treatment, plasma treatment, and frame treatment, or a coating layer such as an easy-adhesion layer may be provided.

[0070] (Method for measuring composite elastic modulus) The composite elastic modulus described above can be obtained by a nanoindentation method. A method for measuring the composite elastic modulus will be described below. Here, as an example, the measurement target is the anchor coat layer 2 of the laminate 10.

[0071] First, a measurement sample (test piece) is obtained from the laminate 10 by the same method as the measurement sample preparation method described in the Examples given later.

[0072] Next, the obtained test piece is placed in a nanoindenter. Here, the test piece is placed in the nanoindenter so that an indenter provided in the nanoindenter contacts the cross section of the anchor coat layer 2 perpendicularly.

[0073] Next, as shown in FIG. 5, the indenter 30 is pressed into the anchor coat layer 2. The pressing speed is set to 50 nm / sec. FIG. 5 is a cross-sectional view that shows a state in which the indenter 30 is pressed into the anchor coat layer 2 at the maximum depth. In FIG. 5, h max A indicates the maximum depth of indentation into the anchor coat layer 2, i.e., the maximum displacement. c indicates the contact projection area. h c indicates the contact depth. In the process of pressing the indenter 30, the load applied to the anchor coat layer 2 and the pressing depth are measured by a nanoindenter. The holding time at the maximum depth is 1 second.

[0074] A Berkovich-type diamond indenter manufactured by Bruker Japan Co., Ltd. is used as the indenter 30. The Berkovich-type diamond indenter has a three-sided pyramid structure, with the interior angle of the indenter being 142.35°, the angle between the center line and the face being 65.35°, and the aspect ratio of the indenter being 1:8.

[0075] Next, the indenter 30 is pulled out from the anchor coat layer 2. The pulling speed is set to 50 nm / sec. During this process, the load applied to the anchor coat layer 2 and the indentation depth are measured by the nanoindenter. max indicates the maximum load on the unloading curve.

[0076] According to the above-mentioned operation, for example, the relationship shown in FIG. 6 can be obtained. FIG. 6 is a graph showing a load-displacement curve. In FIG. 6, the vertical axis represents the load P applied to the anchor coat layer 2, and the horizontal axis represents the pressing depth of the indenter 30, that is, the displacement h. In FIG. 6, when the load P is 0, the indenter 30 is not in contact with the anchor coat layer 2. The position where the displacement h is 0 is the starting position where the load P applied to the anchor coat layer 2 increases from 0. In FIG. 6, the curve where the load P increases from 0 to the right in response to the increase in the displacement h shows the relationship between the load P and the displacement h in the process of pressing the indenter 30 into the anchor coat layer 2. The curve where the load P decreases to a negative value in response to the decrease in the displacement h is the unloading curve. The unloading curve shows the relationship between the load and the displacement in the process of pulling the indenter 30 out of the anchor coat layer 2.

[0077] Next, the contact depth h c Contact depth h c can be calculated using the following formula (1).

[0078]

number

[0079]

number

[0080]

number

[0081] Next, the composite elastic modulus Er is calculated based on the contact projection area Ac and the contact stiffness S. The composite elastic modulus Er can be calculated by the following formula (4).

[0082]

number

[0083] [Variations] The laminate can be modified in various ways. For example, as described below, the laminate may have a laminate structure in which the first base layer 1 has a laminated structure with respect to the laminate 10 shown in FIG. 1. In this case, the laminate structure preferably includes a skin layer and a core layer in contact with the anchor coat layer 2. Modifications are described below with reference to FIG. 2. The matters described with reference to FIG. 1 can be applied alone or in combination to the laminate according to the modification described here.

[0084] FIG. 2 is a partial cross-sectional view that illustrates a laminate according to a modified example of the first embodiment. The laminate 20 shown in Fig. 2 is similar to the laminate 10 described with reference to Fig. 1, except that the first base material layer 1 has a laminate structure including a skin layer 1a and a core layer 1b in contact with the anchor coat layer 2. The matters described for the laminate 10 are also applied to the anchor coat layer 2 in this manner, but due to the unique structure of the laminate 20 in which the skin layer 1a is in contact with the anchor coat layer 2 described below, the anchor coat layer 2 preferably has a cross-sectional hardness in the range of 200 MPa to 350 MPa, as described below.

[0085] (1st base layer) The first base layer 1 is a film that serves as one of the supports and contains polyolefin. The first base layer 1 has a laminated structure including a skin layer 1a and a core layer 1b. <Skin layer 1a> The skin layer 1a included in the first base material layer 1 is interposed between the core layer 1b, which is another layer included in the first base material layer 1, and the anchor coat layer 2, and is in contact with the anchor coat layer 2. The skin layer 1a increases the adhesion between the first base material layer 1 and the anchor coat layer 2, and makes it difficult for interlayer peeling to occur between the first base material layer 1 and the anchor coat layer 2 even after retort treatment.

[0086] The skin layer 1a preferably contains polyolefin and may be made of a polyolefin film. The resin constituting the polyolefin film may be, for example, a homopolymer of an α-olefin, such as polyethylene, polypropylene, or polybutene, or may be a copolymer of two or more kinds of α-olefins. The copolymer may be a random copolymer or a block copolymer. The resin constituting the polyolefin film may be a homopolymer of an α-olefin or a copolymer of two or more kinds of α-olefins, and may be used alone or in combination of two or more kinds.

[0087] In one embodiment, the resin constituting the polyolefin film is preferably a copolymer of propylene and another α-olefin. The other α-olefin is an α-olefin having 2 to 6 carbon atoms other than propylene, such as ethylene, 1-butene, and 1-hexene. The content of the other α-olefin comonomer component contained in the copolymer is preferably within a range of, for example, 0.5 to 15 mol%, and more preferably within a range of 0.6 to 11 mol%.

[0088] Examples of such propylene-based copolymers include ethylene-propylene random copolymers, 1-butene-propylene random copolymers, ethylene-1-butene-propylene random copolymers, and ethylene-propylene block copolymers.

[0089] The polyolefin film constituting the skin layer 1a may be a stretched film or a non-stretched film. From the viewpoints of impact resistance, heat resistance, water resistance, dimensional stability, etc., the polyolefin film may be a stretched film. This makes it possible to make the laminate 20 more suitable for applications in which it is subjected to high temperature and high pressure or high temperature and high humidity environments such as retort processing and boiling processing. The stretching method is not particularly limited. The stretching method may be any method, such as stretching by inflation, uniaxial stretching, biaxial stretching, etc., as long as a film with stable dimensions can be supplied. The first base layer 1 including the skin layer 1a and the core layer 1b is obtained, for example, by co-extruding the resin for forming the skin layer 1a and the resin for forming the core layer 1b, and then biaxially stretching them.

[0090] The skin layer 1a has a cross-sectional hardness of 150 MPa or less at room temperature (25°C). The cross-sectional hardness of the skin layer 1a being 150 MPa or less contributes to improving the abuse resistance of the laminate 20. Here, the upper limit of the cross-sectional hardness of the anchor coat layer 2 adjacent to the skin layer 1a is preferably 350 MPa or less, as described below. By setting the cross-sectional hardness of the skin layer 1a to 150 MPa or less and the cross-sectional hardness of the anchor coat layer 2 to 350 MPa or less, it is possible to generate flexibility in the lower layer of the inorganic barrier layer 3. This makes it difficult for the inorganic barrier layer 3 to crack when physical stress such as bending is applied to the laminate 20. This effect is difficult to obtain by adjusting the upper limit of the cross-sectional hardness of only one of the skin layer 1a and the anchor coat layer 2. It is more preferable that the cross-sectional hardness of the skin layer 1a is 120 MPa or less.

[0091] The cross-sectional hardness of the skin layer 1a is 150 MPa or less, whereas the cross-sectional hardness of the anchor coat layer 2 is preferably in the range of 200 MPa to 350 MPa. In this case, the cross-sectional hardness of the skin layer 1a is significantly lower than that of the anchor coat layer 2. In this way, it is preferable to make the cross-sectional hardness of the skin layer 1a lower than that of the anchor coat layer in order to suppress the deterioration of the gas barrier property after the retort treatment. That is, by making the cross-sectional hardness of the skin layer 1a lower than that of the anchor coat layer 2, the contraction of the first base layer 1 during the retort treatment is not easily transmitted to the inorganic barrier layer 3. Therefore, the inorganic barrier layer 3 is less likely to crack, and the deterioration of the gas barrier property after the retort treatment is suppressed. When the cross-sectional hardness of the skin layer 1a is H1 and the cross-sectional hardness of the anchor coat layer 2 is H2, the difference in cross-sectional hardness between the anchor coat layer 2 and the skin layer 1a (H2-H1) is preferably 50 MPa or more, more preferably 100 MPa or more. On the other hand, the upper limit of the difference in cross-sectional hardness between the skin layer 1a and the anchor coat layer 2 (H2-H1) is not particularly limited, but may be, for example, 330 MPa or less, or 200 MPa or less.

[0092] In the skin layer 1a, the cross-sectional hardness at room temperature (25°C) is preferably 20 MPa or more. In this case, the effect of improving the adhesion between the anchor coat layer 2 and the skin layer 1a is further enhanced, making it more difficult for interlayer peeling to occur between the anchor coat layer 2 and the first base layer 1. In the skin layer 1a, the cross-sectional hardness is more preferably 40 MPa or more. The hardness of this cross section is measured using a nano-indentation method, which will be described later with reference to the drawings.

[0093] The thickness of the skin layer 1a is preferably within the range of 0.2 to 1.8 μm. If the thickness of the skin layer 1a is excessively large, the heat resistance decreases, and the barrier performance after retort decreases. If the thickness of the skin layer 1a is excessively small, the adhesion with the anchor coat layer decreases. The thickness of the skin layer 1a is more preferably within the range of 0.6 to 1.4 μm. The main surface of the skin layer 1a on which the anchor coat layer 2 is formed may be subjected to various pretreatments such as corona treatment, plasma treatment, and flame treatment within a range that does not impair the barrier performance.

[0094] <Core layer 1b> The core layer 1b includes polyolefin. The core layer 1b may be made of a polyolefin film. Examples of the polyolefin film include a polyethylene film, a polypropylene film, and a polybutene film. The polyolefin film may be an acid-modified polyolefin film obtained by graft-modifying a polyolefin with an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like.

[0095] The polyolefin film constituting the core layer 1b may be a stretched film or a non-stretched film. From the viewpoints of impact resistance, heat resistance, water resistance, dimensional stability, etc., the polyolefin film may be a stretched film. This makes it possible to make the laminate 20 more suitable for applications in which it is subjected to high temperature and high pressure or high temperature and high humidity environments such as retort processing and boiling processing. The stretching method is not particularly limited. The stretching method may be any method, such as stretching by inflation, uniaxial stretching, biaxial stretching, etc., as long as a film with stable dimensions can be supplied. As described above, the first base layer 1 including the skin layer 1a and the core layer 1b is obtained, for example, by co-extruding the resin for forming the skin layer 1a and the resin for forming the core layer 1b, and then biaxially stretching them.

[0096] The thickness of the core layer 1b is not particularly limited. For example, the thickness of the first base layer 1 including the skin layer 1a can be appropriately set according to the application so as to be within the range of 6 to 200 μm. In one example, the thickness of the first base layer 1 may be within the range of 9 to 50 μm, or may be within the range of 12 to 38 μm, from the viewpoint of obtaining excellent impact resistance and excellent gas barrier properties.

[0097] (Anchor coat layer) The laminate 20 includes an anchor coat layer 2 between the first base layer 1 and the inorganic barrier layer 3. As described above, the anchor coat layer 2 has a cross-sectional composite elastic modulus in the range of 3.5 to 6.5 GPa at room temperature (25°C) and a thickness in the range of 0.4 to 3.0 µm. The anchor coat layer 2 preferably has a cross-sectional hardness in the range of 200 MPa or more and 350 MPa or less at room temperature (25°C). The anchor coat layer 2 provides the laminate 20 with excellent abuse resistance and adhesion, as described below.

[0098] In the anchor coat layer 2, the cross-sectional hardness of 350 MPa or less contributes to improving the abuse resistance of the laminate 20. By setting the cross-sectional hardness to 350 MPa or less, the anchor coat layer 2 becomes flexible, and the inorganic barrier layer 3 is less likely to crack when physical stress such as bending is applied to the laminate 20. However, as described above, this effect is easily obtained when the cross-sectional hardness of the anchor coat layer 2 is 350 MPa or less and the cross-sectional hardness of the skin layer 1a is 150 MPa or less, and is difficult to obtain by adjusting the upper limit of the cross-sectional hardness of only one of the anchor coat layer 2 and the skin layer 1a. In the anchor coat layer 2, the cross-sectional hardness is more preferably 300 MPa or less.

[0099] In the anchor coat layer 2, the cross-sectional hardness of 200 MPa or more contributes to improving the adhesion of the laminate 20. By making the cross-sectional hardness 200 MPa or more, the adhesion of the laminate 10 is improved, and delamination between the anchor coat layer 2 and the inorganic barrier layer 3 is less likely to occur even after treatment in a high temperature and high pressure or high temperature and high humidity environment such as retort treatment. It is more preferable that the cross-sectional hardness of the anchor coat layer 2 is 250 MPa or more.

[0100] In this way, the cross-sectional hardness of the anchor coat layer 2 is set to 200 MPa or more and 350 MPa or less, and the cross-sectional hardness of the skin layer 1a, which is a layer constituting the first base material layer and adjacent to the anchor coat layer, is set to 150 MPa or less, thereby imparting excellent gas barrier properties, abuse resistance, and adhesion to the laminate 20. In this way, the laminate 20 according to this modification has excellent gas barrier properties after treatment in a high-temperature, high-pressure, or high-temperature, high-humidity environment such as retort treatment or boiling treatment, and can maintain good gas barrier properties even when subjected to physical stress such as bending. In addition, the laminate 20 according to this modification can maintain high interlayer adhesion strength after treatment in a high-temperature, high-pressure, or high-temperature, high-humidity environment such as retort treatment or boiling treatment. Note that this cross-sectional hardness is measured using the nanoindentation method as described above, and will be described later with reference to the drawings.

[0101] The anchor coating agent used to form the anchor coating layer 2 may be the same material as the anchor coating agent described for the laminate 10. When the anchor coating agent contains the above-mentioned polyurethane resin and curing agent, the above-mentioned cross-sectional hardness of the anchor coating layer 2 can be adjusted, for example, by the solid mass ratio of the polyurethane resin and the curing agent contained in the anchor coating agent. The solid mass ratio of the curing agent to the urethane resin in the anchor coating agent [curing agent / polyurethane resin] is preferably within the range of 30 / 100 to 50 / 100, and more preferably within the range of 35 / 100 to 40 / 100.

[0102] A known coating method can be used as a method for coating the anchor coat layer 2 onto the first substrate layer 1, and for example, a method similar to the coating method of the anchor coat agent described for the laminate 10 can be used.

[0103] (Hardness measurement method) The above-mentioned cross-sectional hardness is obtained by a nanoindentation method. A method for measuring hardness will be described below. Here, as an example, the measurement target is the anchor coat layer 2 of the laminate 10.

[0104] First, a measurement sample (test piece) is obtained from the laminate 10 by the same method as the measurement sample preparation method described in the Examples given later.

[0105] Next, the obtained test piece is placed in a nanoindenter. Here, the test piece is placed in the nanoindenter so that the indenter of the nanoindenter contacts the cross section of the anchor coat layer 2 perpendicularly. The nanoindenter used is one capable of surface detection at 1 μN. When placing the test piece, trimming of the embedding resin may be performed as necessary.

[0106] Next, as shown in FIG. 5, the indenter 30 is pressed into the anchor coat layer 2. The pressing speed is set to 30 nm / sec. FIG. 5 is a cross-sectional view showing a state in which the indenter 30 is pressed into the anchor coat layer 2 at the maximum depth. In FIG. 5, h max A indicates the maximum depth of indentation into the anchor coat layer 2, i.e., the maximum displacement. c indicates the contact projection area. h c indicates the contact depth. In the process of pressing the indenter 30, the load applied to the anchor coat layer 2 and the pressing depth are measured by a nanoindenter. The holding time at the maximum depth is 1 second.

[0107] The measurement device used is a Hysitron TI-Premier (product name) manufactured by Bruker Japan Co., Ltd., and the indenter 30 is a Berkovich-type diamond indenter manufactured by Bruker Japan Co., Ltd. The Berkovich-type diamond indenter has a three-sided pyramid structure, with the interior angle of the indenter being 142.35°, the angle between the center line and the face being 65.35°, and the aspect ratio of the indenter being 1:8.

[0108] Next, the indenter 30 is pulled out from the anchor coat layer 2. The pulling speed is set to 30 nm / sec. During this process, the load applied to the anchor coat layer 2 and the indentation depth are measured by the nanoindenter. max indicates the maximum load on the unloading curve.

[0109] According to the above-mentioned operation, for example, the relationship shown in FIG. 6 can be obtained. FIG. 6 is a graph showing a load-displacement curve. In FIG. 6, the vertical axis represents the load P applied to the anchor coat layer 2, and the horizontal axis represents the pressing depth of the indenter 30, that is, the displacement h. In FIG. 6, when the load P is 0, the indenter 30 is not in contact with the anchor coat layer 2. The position where the displacement h is 0 is the starting position where the load P applied to the anchor coat layer 2 increases from 0. In FIG. 6, the curve where the load P increases from 0 to the right in response to the increase in the displacement h shows the relationship between the load P and the displacement h in the process of pressing the indenter 30 into the anchor coat layer 2. The curve where the load P decreases to a negative value in response to the decrease in the displacement h is the unloading curve. The unloading curve shows the relationship between the load and the displacement in the process of pulling the indenter 30 out of the anchor coat layer 2.

[0110] Next, the contact depth h c Contact depth h c can be calculated using the following formula (1).

[0111]

number

[0112]

number

[0113]

number

[0114]

number

[0115] Next, the contact projection area A c and the maximum load P of the unloading curve max The hardness H can be calculated based on the above formula (5).

[0116]

number

[0117] The hardness H is measured at multiple points, for example, 10 to 20 points, per test piece. The average value of these hardness H values ​​is obtained as the above-mentioned hardness.

[0118] [Second embodiment] Fig. 3 is a partial cross-sectional view showing an example of a packaging material according to a second embodiment of the present invention. The packaging material 100 shown in Fig. 3 includes the laminate 10 according to the first embodiment described above, and includes a sealant layer 11, a first adhesive layer 12, a first base material layer 1, an anchor coat layer 2, an inorganic barrier layer 3, a second adhesive layer 13, and a second base material layer 14 in this order.

[0119] Fig. 4 is a partial cross-sectional view showing a packaging material according to a modified example of the second embodiment. The packaging material 200 shown in Fig. 4 includes the above-mentioned laminate 20, and includes a sealant layer 11, a first adhesive layer 12, a core layer 1b, a skin layer 1a, an anchor coat layer 2, an inorganic barrier layer 3, a second adhesive layer 13, and a second base layer 14 in this order.

[0120] As described in relation to the laminates 10 and 20, the packaging materials 100 and 200 according to the present embodiment are excellent in gas barrier properties, abuse resistance, and adhesion after retort treatment. The packaging materials 100 and 200 according to the present embodiment can maintain good gas barrier properties and high interlayer adhesion even when subjected to physical stress such as bending after treatment in a high-temperature, high-pressure or high-temperature, high-humidity environment such as retort treatment. Among the layers contained in the packaging materials 100 and 200, each layer other than the layers contained in the laminates 10 and 20 described above will be described below.

[0121] (Sealant layer) The sealant layer 11 is formed on the surface of the laminates 10 and 20 on the side of the first base material layer 1 via a first adhesive layer 12. The sealant layer 11 imparts heat sealing properties to the packaging materials 100 and 200.

[0122] The sealant layer 11 may contain a thermoplastic resin, and a polyolefin resin is preferably used as the thermoplastic resin. The sealant layer 11 preferably contains a polyolefin film, and may be made of a polyolefin film.

[0123] Specific examples of the polyolefin resin contained in the sealant layer 11 include ethylene resins such as low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-(meth)acrylic acid copolymer; blended resins of polyethylene and polybutene; and polypropylene resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer. The thermoplastic resin used as the material for the sealant layer 11 can be appropriately selected depending on the intended use of the packaging materials 100 and 200 and the temperature conditions of boiling, retort treatment, and the like.

[0124] The polyolefin film constituting the sealant layer 11 may contain various additives such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, and a tackifier.

[0125] The thickness of the sealant layer 11 is determined by the mass of the contents contained in the package including the packaging materials 100 and 200, the shape of the package, and the like, but is preferably within the range of approximately 30 to 150 μm.

[0126] The sealant layer 11 can be formed by a known lamination method, such as a dry lamination method in which a film-like sealant layer is bonded with an adhesive such as a one-component curing or two-component curing urethane adhesive, a non-solvent dry lamination method in which a film-like sealant layer is bonded with a solvent-free adhesive, or an extrusion lamination method in which the above-mentioned thermoplastic resin is heated and melted, extruded into a curtain shape, and bonded together.

[0127] Among the above-mentioned forming methods, the dry lamination method is preferred because it has high resistance to retort treatment, particularly high-temperature hot water treatment of 120° C. or higher. On the other hand, if the package is used for an application in which it is treated at a temperature of 85° C. or lower, the lamination method is not particularly limited.

[0128] (2nd base layer) The second base layer 14 is formed on the inorganic barrier layer 3 side of the laminates 10 and 20 via a second adhesive layer 13. The second base layer 14 may be made of a polyolefin film. Examples of the polyolefin film include a polyethylene film (PE), a polypropylene film (PP), and a polybutene film (PB). Examples of the polyolefin film include an acid-modified polyolefin film obtained by graft-modifying a polyolefin with an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like.

[0129] The polyolefin film constituting the second base layer 14 may be a stretched film or a non-stretched film. From the viewpoints of impact resistance, heat resistance, water resistance, dimensional stability, and the like, the polyolefin film may be a stretched film. This makes it possible to make the packaging materials 100 and 200 more suitable for applications in which retort treatment or boiling treatment is performed. The stretching method is not particularly limited. The stretching method may be any method, such as stretching by inflation, uniaxial stretching, or biaxial stretching, as long as a dimensionally stable film can be supplied.

[0130] The thickness of the second base layer 14 is not particularly limited. Depending on the application of the packaging materials 100 and 200, the thickness of the second base layer 14 can be, for example, within the range of 6 to 200 μm. From the viewpoint of obtaining excellent impact resistance and excellent gas barrier properties, the thickness of the second base layer 14 may be within the range of 9 to 50 μm, or may be within the range of 12 to 38 μm.

[0131] The second base layer 14 may be subjected to various pretreatments such as corona treatment, plasma treatment, and frame treatment on the surface on the side of the laminates 10 and 20 as long as the barrier performance is not impaired, or a coating layer such as an easy-adhesion layer may be provided.

[0132] (1st adhesive layer) The packaging materials 100 and 200 include a first adhesive layer 12 between the sealant layer 11 and the first base material layer 1, which adheres them together. For example, polyester-isocyanate resin, urethane resin, polyether resin, etc. can be used as the material for the first adhesive layer 12. To use a package including the packaging materials 100 and 200 for retort applications, a two-component curing urethane adhesive that is resistant to retort can be preferably used.

[0133] The thickness of the first adhesive layer 12 is not particularly limited, but is preferably in the range of 0.5 to 8.0 μm, and more preferably in the range of 2.0 to 4.0 μm. If the thickness of the first adhesive layer 12 exceeds the upper limit, the cost is likely to increase due to an increase in the amount of material used and a longer film formation time, which is not preferable from an economical point of view. If the thickness of the first adhesive layer 12 is below the lower limit, sufficient interlayer adhesive strength cannot be obtained.

[0134] (Second adhesive layer) The packaging materials 100 and 200 include a second adhesive layer 13 between the second base material layer 14 and the inorganic barrier layer 3 to bond them together. The material of the second adhesive layer 13 is the same as that of the first adhesive layer 12 described above. The thickness of the second adhesive layer 13 is also the same as that of the second adhesive layer 13 described above.

[0135] [Third embodiment] According to a third embodiment of the present invention, a package including the above-mentioned packaging material 100 is provided. Also, a package including the above-mentioned packaging material 200 is provided. These packages may be known bags such as a two-sided bag, a three-sided bag, a two-sided bag, a standing pouch, or a gusset bag, or may be a container including a container body having an opening and a lid that closes the opening. In the latter case, the packaging materials 100 and 200 can be used as at least a part of the lid.

[0136] The package according to the present embodiment has excellent resistance to abuse and adhesion, as described in relation to the laminates 10 and 20, and the packaging materials 100 and 200. The package according to the present embodiment can maintain good gas barrier properties and high interlayer adhesive strength even when subjected to physical stress such as bending after treatment in a high-temperature, high-pressure or high-temperature, high-humidity environment such as retort treatment. Therefore, the package according to the present embodiment is suitably used as, for example, a retort pouch.

[0137] [Fourth embodiment] According to a fourth embodiment of the present invention, a packaged article is provided that includes the above-mentioned package and a content accommodated therein. In the package, for example, a sealant layer 11 is in contact with a space that accommodates the content. Any content can be used. In one example, the content is a fluid one such as a liquid or an aggregate of rice. EXAMPLES

[0138] Tests carried out in relation to the present invention are described below. <1> Test Example 1 <1.1> Preparation of anchor coating agent AC1 Anchor coating agent AC1 was prepared by mixing the following Takelac WPB-341A as the base agent and the following Takenate WD-725 as the hardener in a solids mass ratio of hardener / base agent = 34.7 / 100.

[0139] Takelac WPB-341A: Aqueous dispersion of polyurethane resin formed from acid group-containing polyurethane and polyamine, manufactured by Mitsui Chemicals, Inc., solids concentration 30 mass%. Takenate WD-725: Aqueous dispersion of polyisocyanate with nonionic groups, manufactured by Mitsui Chemicals, Inc., solids concentration 99% by mass.

[0140] <1.2> Manufacturing of packaging materials (Example 1) The packaging material 100 shown in FIG. 3 was produced by the following method. First, a stretched polypropylene film (thickness 20 μm) with one side corona-treated was prepared as the first base layer 1. The anchor coating agent AC1 prepared above was applied to the corona-treated surface of this first base layer 1 by gravure roll coating, and dried and cured at 60° C. to form an anchor coating layer 2 (thickness 1.2 μm).

[0141] Next, a 40 nm-thick transparent inorganic oxide layer (silica vapor deposition layer) made of silicon oxide was formed as the inorganic barrier layer 3 on the anchor coat layer 2 using a vacuum deposition apparatus using an electron beam heating method, thereby obtaining a laminate 10.

[0142] Next, a two-component curing polyurethane adhesive (Takelac A525 / Takenate A52, manufactured by Mitsui Chemicals, Inc.) was applied to the surface of the first base layer 1 of the laminate 10 obtained above so that the film thickness after drying would be 3 μm to form a first adhesive layer 12, and then a sealant layer 11 was dry laminated. As the sealant layer 11, a non-oriented polypropylene film (cast polypropylene; CPP) having a thickness of 100 μm was used.

[0143] Next, the same two-component curing polyurethane adhesive as the first adhesive layer 12 was applied to the inorganic barrier layer 3 side of the laminate 10 so that the film thickness after drying was 3 μm to form a second adhesive layer 13, and then dry laminated with a second base material layer 14. Oriented polypropylene (OPP) having a thickness of 30 μm was used as the second base material layer 14. In this way, a packaging material 100 shown in FIG. 3 was obtained.

[0144] (Example 2) A packaging material 100 was produced in the same manner as in Example 1, except for the following points: In this example, instead of using the anchor coating agent AC1 in which the base agent and the hardener were mixed at a solid content mass ratio of hardener / base agent = 34.7 / 100, an anchor coating agent AC2 in which the base agent and the hardener were mixed at a solid content mass ratio of hardener / base agent = 41.3 / 100 was used as the anchor coating agent.

[0145] (Example 3) A packaging material 100 was produced in the same manner as in Example 1, except for the following points: In this example, instead of using the anchor coating agent AC1 in which the base agent and the hardener were mixed at a solid content mass ratio of hardener / base agent = 34.7 / 100, an anchor coating agent AC3 in which the base agent and the hardener were mixed at a solid content mass ratio of hardener / base agent = 47.2 / 100 was used as the anchor coating agent.

[0146] (Example 4) A packaging material 100 was produced in the same manner as in Example 3, except for the following points: In this example, the thickness of the anchor coat layer 2 was changed from 1.2 μm to 0.5 μm.

[0147] (Example 5) A packaging material 100 was produced in the same manner as in Example 3, except for the following points: In this example, the thickness of the anchor coat layer 2 was changed from 1.2 μm to 2.8 μm.

[0148] Comparative Example 1 A packaging material 100 was produced in the same manner as in Example 1, except for the following points: In this comparative example, instead of using the anchor coating agent AC1 in which the base agent and the hardener were mixed at a solid content mass ratio of hardener / base agent = 34.7 / 100, an anchor coating agent AC1R in which the base agent and the hardener were mixed at a solid content mass ratio of hardener / base agent = 28.7 / 100 was used as the anchor coating agent.

[0149] Comparative Example 2 A packaging material 100 was produced in the same manner as in Example 1, except for the following points: In this comparative example, instead of using anchor coating agent AC1 in which the base agent and the hardener were mixed at a solid content mass ratio of hardener / base agent = 34.7 / 100, anchor coating agent AC2R in which the base agent and the hardener were mixed at a solid content mass ratio of hardener / base agent = 51.5 / 100 was used as the anchor coating agent.

[0150] Comparative Example 3 A packaging material 100 was produced in the same manner as in Example 3, except for the following points: In this comparative example, the thickness of the anchor coat layer 2 was changed from 1.2 μm to 0.3 μm.

[0151] Comparative Example 4 A packaging material 100 was produced in the same manner as in Example 3, except for the following points: That is, in this comparative example, the thickness of the anchor coat layer 2 was changed from 1.2 μm to 3.2 μm.

[0152] <1.3> Evaluation (composite elastic modulus) For the anchor coat layer 2 of the packaging materials according to Examples 1 to 5 and Comparative Examples 1 to 4, the composite elastic modulus of the cross section was measured by using a nanoindentation method. [Preparation of measurement samples] Both sides of the packaging materials (hereinafter simply referred to as "films") according to Examples 1 to 5 and Comparative Examples 1 to 4 were each subjected to a corona treatment at 0.20 kW (apparatus: Corona Treater CT-0212 manufactured by Kasuga Electric Co., Ltd.), and then the films were cut into wedges with a base of 1.0 mm and a height of 5.0 mm using a razor. The cut films were embedded in a photocurable resin and cured with a halogen lamp KTX-100R (manufactured by Kenko Tokina Co., Ltd.). The photocurable resin used was D-800 manufactured by Toagosei Co., Ltd.

[0153] The photocured film embedding resin was fixed with an insert for AFM sample holder, and the cross-section of the film was cut with a glass knife at room temperature (25°C). Then, the final cross-section was cut with a diamond knife at room temperature with a cutting speed of 1.0 mm / s and a cutting layer thickness of 500 nm, and the cutting was completed when a mirror surface was obtained. An ultramicrotome (Leica EM UC7) and a cryosystem (Leica EM FC7) were used as the cross-section cutting device. The cutting direction of the knife was parallel to the layer interface.

[0154] [Measurement of composite elastic modulus using nanoindentation method] The measurement device used was a Hysitron TI-Premier (product name) manufactured by Bruker Japan, Ltd., and the indenter used was a Berkovich-type diamond indenter manufactured by Bruker Japan, Ltd. The nanoindentation measurement was performed in displacement control mode by indenting to a depth of 50 nm at a indentation speed of 50 nm / s, holding the sample at the maximum depth for 1 second, and then unloading at a speed of 50 nm / s.

[0155] The measurements were performed by obtaining a shape image of the cross section of the sample using the shape measurement function of a measuring device that scans the sample surface with an indenter, and then specifying 20 points on the target layer (anchor coat layer 2) at intervals of 1 μm or more from the shape image. In calculating the composite elastic modulus, a standard sample of fused quartz was tested in advance to calibrate the relationship between the contact depth and the contact projected area of ​​the indenter and sample. After that, the unloading curve in the 60-95% range of the maximum load at the time of unloading was analyzed by the Oliver-Pharr method to calculate the composite elastic modulus.

[0156] (Gas barrier properties, resistance to abuse and adhesion after retort processing) Using each of the packaging materials according to Examples 1 to 5 and Comparative Examples 1 to 4, samples for evaluation of gas barrier properties, abuse resistance, and adhesion after retort treatment were prepared. First, 20 cm x 20 cm test pieces were cut out from each packaging material in sets of 2 sheets x 3, and 3 sets of test pieces were prepared by stacking 2 sheets so that the sealant layer was on the inside. Then, 3 sides of each were heat-sealed to form a bag shape. Next, each was filled with water, and the remaining sides were heat-sealed to prepare 3 sets of evaluation samples for each packaging material. These samples were retorted for 30 minutes at 0.2 MPa and 121°C using a hot water storage retort kettle, and then the gas barrier properties, abuse resistance, and adhesion were evaluated by the method described below.

[0157] <Gas barrier properties> The oxygen transmission rate (OTR) of each sample after the retort treatment was measured using an oxygen transmission tester OX-TRAN (registered trademark) 2 / 20 manufactured by Modern Control under conditions of a temperature of 30°C and a relative humidity of 70%. The measurement was performed in accordance with JIS K-7126 Method B (constant pressure method) and ASTM D3985. From the measurement results, the gas barrier properties after the retort treatment were evaluated based on the following criteria. A: Oxygen permeability is 10cc / m 2 / day / atm or less, and has excellent gas barrier properties after retort processing. B: Oxygen permeability is 10cc / m 2 / day / atm, and the gas barrier properties after retort treatment cannot be said to be excellent.

[0158] <Abuse resistance> Each sample after the retort treatment was subjected to a Gelbo Flex test, which was performed by bending the sample five times using a Gelbo Flex tester manufactured by Tester Sangyo, as specified in MIL B131 (ASTMF392). The oxygen permeability of each sample after the Gelbo Flex test was measured under the same conditions and method as above. From the measurement results, the abuse resistance after the retort treatment was evaluated based on the following criteria. A: Oxygen permeability is 20cc / m 2 / day / atm or less, and has excellent resistance to abuse after retort processing. B: Oxygen permeability is 20cc / m 2 / day / atm, and the abuse resistance after retort processing cannot be said to be excellent.

[0159] <Adhesion> For each sample after the retort treatment, the 180° peel strength between the anchor coat layer 2 and the inorganic barrier layer 3 was measured using a tensile tester Tensilon RTC-1250 manufactured by Orientec Co., Ltd. From the measurement results, the adhesion after the retort treatment was evaluated according to the following criteria. A: The peel strength is 2.0N / 15mm or more, and the adhesion after retort processing is very excellent. B: The peel strength is 1.5 N / 15 mm or more and less than 2.0 N / 15 mm, and the adhesion after retort treatment is excellent. C: The peel strength is less than 1.5 N / 15 mm, and the adhesion after retort treatment is not excellent.

[0160] The measurement and test results and evaluations for each packaging material are summarized in Table 1 below.

[0161] [Table 1]

[0162] From the results shown in Table 1, it can be seen that excellent adhesion and abuse resistance are imparted to the packaging material (laminate) by setting the film thickness in the range of 0.3 to 4.0 μm and the cross-sectional composite elastic modulus in the range of 3.5 to 6.5 GPa in the anchor coat layer 2. Therefore, the package including the packaging material according to this embodiment can maintain good gas barrier properties and high interlayer adhesive strength even when subjected to physical stress such as bending after treatment in a high temperature and high pressure or high temperature and high humidity environment such as retort treatment or boiling treatment.

[0163] <2> Test Example 2 <2.1> Preparation of the first base layer <2.1.1> Preparation of first base layer 1A An ethylene-1-butene-propylene random copolymer resin (ethylene content: 5 mol%, 1-butene content: 6 mol%) was prepared as the material for the skin layer 1a, and a homopolypropylene resin was prepared as the material for the core layer 1b. These resins were co-extruded and then biaxially stretched to produce a first base layer 1A having a thickness of 20 μm, which was composed of a skin layer 1a having a thickness of 0.7 μm and a core layer 1b having a thickness of 19.3 μm.

[0164] <2.1.2> Preparation of first base layer 1B The first base layer 1B was produced under the same conditions as the first base layer 1A, except that an ethylene-propylene random copolymer resin (ethylene content: 7.5 mol%) was used instead of an ethylene-1-butene-propylene random copolymer resin (ethylene content: 5 mol%, 1-butene content: 6 mol%) as the material for the skin layer 1a.

[0165] <2.1.3> Preparation of first base layer 1C The first base layer 1C was prepared in the same manner as the first base layer 1A, except that an ethylene-1-butene-propylene random copolymer resin (ethylene content: 2.5 mol%, 1-butene content: 3.5 mol%) was used as the material for the skin layer 1a instead of an ethylene-1-butene-propylene random copolymer resin (ethylene content: 5 mol%, 1-butene content: 6 mol%).

[0166] <2.1.4> Preparation of first base layer 1D The first base layer 1D was produced under the same conditions as the first base layer 1A, except that an ethylene-propylene random copolymer resin (ethylene content: 5.0 mol%) was used instead of an ethylene-1-butene-propylene random copolymer resin (ethylene content: 5 mol%, 1-butene content: 6 mol%) as the material for the skin layer 1a.

[0167] <2.1.5> Preparation of first base layer 1E The first base layer 1E was prepared under the same conditions as the first base layer 1A, except that an ethylene-propylene random copolymer resin (ethylene content: 3.2 mol%) was used instead of an ethylene-1-butene-propylene random copolymer resin (ethylene content: 5 mol%, 1-butene content: 6 mol%) as the material for the skin layer 1a.

[0168] <2.1.6> Preparation of first base layer 1F The first base layer 1F was produced under the same conditions as the first base layer 1A, except that an ethylene-propylene random copolymer resin (ethylene content: 0.7 mol%) was used instead of an ethylene-1-butene-propylene random copolymer resin (ethylene content: 5 mol%, 1-butene content: 6 mol%) as the material for the skin layer 1a.

[0169] <2.1.7> Preparation of first base layer 1G The first base layer 1G was produced under the same conditions as the first base layer 1A, except that an ethylene-propylene random copolymer resin (ethylene content: 0.6 mol%) was used instead of an ethylene-1-butene-propylene random copolymer resin (ethylene content: 5 mol%, 1-butene content: 6 mol%) as the material for the skin layer 1a.

[0170] <2.1.8> Preparation of first base layer 1H A first base material layer 1I was produced under the same conditions as the first base material layer 1A, except that the thickness of the skin layer 1a was changed from 0.7 μm to 1.8 μm and the thickness of the core layer 1b was changed from 19.3 μm to 18.2 μm.

[0171] <2.1.9> Preparation of first base layer 1I A first base material layer 1J was produced under the same conditions as the first base material layer 1A, except that the thickness of the skin layer 1a was changed from 0.7 μm to 0.2 μm and the thickness of the core layer 1b was changed from 19.3 μm to 19.8 μm.

[0172] <2.2> Preparation of anchor coating agent <2.2.1> Preparation of anchor coating agent AC3R Anchor coating agent AC3R was prepared under the same conditions as anchor coating agent AC1, except that the solid mass ratio of the base agent to the hardener was changed from 47.2 / 100 to 54.5 / 100 (hardener / base agent).

[0173] In addition to the anchor coating agent AC3R prepared here, the anchor coating agents AC1 to AC3, ACR1 and ACR2 prepared in Test Example 1 were used.

[0174] <2.3> Manufacturing of packaging materials <2.3.1> Example 6 The packaging material 200 shown in FIG. 4 was produced by the following method. First, the anchor coating agent AC3 prepared above was applied by gravure roll coating to the surface of the skin layer 1a side of the first base layer 1A prepared above, and then dried and cured at 60°C to form an anchor coating layer 2 (thickness 1.0 μm).

[0175] Next, a 40 nm-thick transparent inorganic oxide layer (silica vapor deposition layer) made of silicon oxide was formed as the inorganic barrier layer 3 on the anchor coat layer 2 using a vacuum deposition apparatus using an electron beam heating method, thereby obtaining a laminate 20.

[0176] Next, a two-component curing polyurethane adhesive (base: Takelac A525, curing agent: Takenate A52, manufactured by Mitsui Chemicals, Inc.) was applied to the surface of the first base layer 1 of the laminate 20 obtained above so that the film thickness after drying would be 3 μm to form a first adhesive layer 12, and then the sealant layer 11 was dry laminated. As the sealant layer 11, a non-oriented polypropylene film (cast polypropylene; CPP) having a thickness of 100 μm was used.

[0177] Next, the same two-component curing polyurethane adhesive as the first adhesive layer 12 was applied to the inorganic barrier layer 3 side of the laminate 20 so that the film thickness after drying was 3 μm to form a second adhesive layer 13, and then the second base material layer 14 was dry laminated. Oriented polypropylene (OPP) having a thickness of 30 μm was used as the second base material layer 14. In this way, the packaging material 200 shown in FIG. 4 was obtained.

[0178] (Examples 7 to 17, Comparative Examples 5 to 7) Packaging materials of Examples 7 to 17 and Comparative Examples 5 to 7 were produced under the same conditions as in Example 6, except that the first base layer 1A or anchor coating agent AC3 used in Example 6 was changed to those shown in Table 2.

[0179] <2.4> Measurement and evaluation of hardness <2.4.1> Hardness For each of the packaging materials according to Examples 6 to 17 and Comparative Examples 5 to 7, the hardness of the cross section of the skin layer 1a and the anchor coat layer 2 (hereinafter, each will be referred to as the "target layer") was measured by the nanoindentation method.

[0180] [Preparation of measurement samples] Both sides of each packaging material (hereinafter also referred to as "film") were corona-treated at 0.20 kW (apparatus: Corona Treater CT-0212 manufactured by Kasuga Electric Co., Ltd.), and the film was then cut into a wedge shape with a base of 1.0 mm and a height of 5.0 mm using a razor. The cut film was embedded in a photocurable resin and cured with a halogen lamp KTX-100R (manufactured by Kenko Tokina Co., Ltd.). The photocurable resin used was D-800 manufactured by Toagosei Co., Ltd.

[0181] The photocured film embedding resin was fixed with an insert for AFM sample holder, and the cross-section of the film was cut with a glass knife at room temperature (25°C). Then, the final cross-section was cut with a diamond knife at room temperature with a cutting speed of 1.0 mm / s and a cutting layer thickness of 100 nm, and the cutting was completed when a mirror surface was obtained. An ultramicrotome (Leica EM UC7) and a cryosystem (Leica EM FC7) were used as the cross-section cutting device. The cutting direction of the knife was parallel to the layer interface.

[0182] [Hardness measurement using nanoindentation method] The measurement device used was a Hysitron TI-Premier (product name) manufactured by Bruker Japan, Ltd., and the indenter used was a Berkovich-type diamond indenter manufactured by Bruker Japan, Ltd. The nanoindentation measurement was performed in displacement control mode by indenting to a depth of 30 nm at a indentation speed of 30 nm / s, holding the sample at the maximum depth for 1 second, and then unloading at a speed of 30 nm / s.

[0183] The measurements were performed by acquiring a cross-sectional shape image of the sample using the shape measurement function of a measuring device that scans the sample surface with an indenter, and then specifying 20 points at intervals of 1 μm or more on the target layer from the shape image. When calculating the hardness, a standard sample of fused quartz was tested in advance to calibrate the relationship between the contact depth of the indenter and the sample and the contact projected area. After that, the unloading curve in the 60-95% region of the maximum load at the time of unloading was analyzed by the Oliver-Pharr method to calculate the hardness. As a result, the hardness of the anchor coat layer 2 was in the range of 200 to 350 MPa in all of Examples 6 to 17, less than 200 MPa in Comparative Example 5, and more than 350 MPa in Comparative Examples 6 and 7. The results of the hardness of the skin layer 1a are shown in Table 2.

[0184] <2.4.2> Composite elastic modulus The cross-sectional composite elastic modulus of the anchor coat layer 2 of each packaging material was measured using a nanoindentation method. The preparation of the measurement sample and the measurement of the composite elastic modulus by nanoindentation were performed under the same conditions as in Test Example 1. The results are shown in Table 2.

[0185] <2.4.3> Gas barrier properties, resistance to abuse and adhesion after retort processing Using each of the packaging materials according to Examples 1 to 12 and Comparative Examples 1 to 6, samples for evaluation of gas barrier properties, abuse resistance, and adhesion after retort treatment were prepared. First, 20 cm x 20 cm test pieces were cut out from each packaging material in sets of 2 sheets x 3, and 3 sets of test pieces were prepared by stacking 2 sheets of test pieces so that the sealant layer 11 was on the inside. Then, 3 sides of each were heat-sealed to form a bag shape. Next, each was filled with water, and the remaining sides were heat-sealed to prepare 3 sets of evaluation samples for each packaging material. These samples were retorted for 30 minutes at 0.2 MPa and 120°C using a hot water storage retort kettle, and then the gas barrier properties, abuse resistance, and adhesion were evaluated by the method described below. The results are shown in Table 2.

[0186] <Gas barrier properties> The oxygen transmission rate (OTR) of each sample after the retort treatment was measured under the same conditions as in Test Example 1. From the measurement results, the gas barrier property after the retort treatment was evaluated based on the same criteria as in Test Example 1.

[0187] <Abuse resistance> For each sample after the retort treatment, a Gelbo Flex test was performed under the same conditions as in Test Example 1, and then the oxygen permeability was measured under the same conditions as in Test Example 1. From the measurement results, the abuse resistance after the retort treatment was evaluated based on the same criteria as in Test Example 1.

[0188] <Adhesion 1> For each sample after the retort treatment, the 180° peel strength between the first base layer 1 and the anchor coat layer 2 was measured using a tensile tester Tensilon RTC-1250 manufactured by Orientec Co., Ltd. From the measurement results, the adhesion after the retort treatment was evaluated according to the following criteria. A: The peel strength is 2.0N / 15mm or more, and the adhesion after retort processing is very excellent. B: The peel strength is 1.5 N / 15 mm or more and less than 2.0 N / 15 mm, and the adhesion after retort treatment is excellent. C: The peel strength is less than 1.5 N / 15 mm, and the adhesion after retort treatment is not excellent.

[0189] <Adhesion 2> For each sample after the retort treatment, the 180° peel strength between the anchor coat layer 2 and the inorganic barrier layer 3 was measured using a tensile tester Tensilon RTC-1250 manufactured by Orientec Co., Ltd. From the measurement results, the adhesion after the retort treatment was evaluated according to the following criteria. A: The peel strength is 2.0N / 15mm or more, and the adhesion after retort processing is very excellent. B: The peel strength is 1.5 N / 15 mm or more and less than 2.0 N / 15 mm, and the adhesion after retort treatment is excellent. C: The peel strength is less than 1.5 N / 15 mm, and the adhesion after retort treatment is not excellent.

[0190] [Table 2]

[0191] The present invention is not limited to the above-mentioned embodiment, and can be modified in various ways without departing from the gist of the present invention. The embodiments may be combined as appropriate, and in that case, the combined effect can be obtained. Furthermore, the above-mentioned embodiment includes various inventions, and various inventions can be extracted by combinations selected from the multiple components disclosed. For example, if the problem can be solved and the effect can be obtained even if some components are deleted from all the components shown in the embodiment, the configuration from which the components are deleted can be extracted as an invention. [Explanation of symbols]

[0192] Reference Signs List 1...first base layer, 1a...skin layer, 1b...core layer, 2...anchor coat layer, 3...inorganic barrier layer, 10...laminate, 11...sealant layer, 12...first adhesive layer, 13...second adhesive layer, 14...second base layer, 20...laminate, 100...packaging material, 200...packaging material

Claims

1. A first substrate layer, an anchor coat layer, and an inorganic barrier layer in this order; the first substrate layer comprises a polyolefin; The packaging material includes a laminate in which the anchor coat layer has a cross-sectional composite elastic modulus in the range of 3.5 to 6.5 GPa and a thickness in the range of 0.4 to 3.0 μm.

2. The first base layer has a layer structure including a skin layer in contact with the anchor coat layer and a core layer, 2. The packaging material according to claim 1, wherein the anchor coat layer has a cross-sectional hardness in the range of 200 MPa or more and 350 MPa or less, and the skin layer has a cross-sectional hardness of 150 MPa or less.

3. The packaging material according to claim 2, wherein the skin layer has a cross-sectional hardness of 20 MPa or more.

4. 3. The packaging material of claim 2, wherein the thickness of said skin layer is in the range of 0.2 to 1.8 μm.

5. 2. The packaging material according to claim 1, wherein the anchor coating layer is a cured film of an anchor coating agent containing a polyurethane resin and a curing agent, and a solid mass ratio of the polyurethane resin to the curing agent in the anchor coating agent [curing agent / polyurethane resin] is within a range of 30 / 100 to 50 / 100.

6. The packaging material according to claim 1 , wherein the inorganic barrier layer contains silicon oxide or aluminum oxide.

7. a sealant layer formed on a surface of the laminate on the side of the first base material layer via a first adhesive layer; a second base layer formed on the inorganic barrier layer side of the laminate via a second adhesive layer; The packaging material of claim 1 .

8. 2. The packaging material according to claim 1, which is for a retort pouch.

9. A package comprising the packaging material according to any one of claims 1 to 8.

10. A packaged article comprising the package according to claim 9 and contents contained therein.

11. A coating composition comprising a first substrate layer, an anchor coat layer, and an inorganic barrier layer in this order; the first substrate layer comprises a polyolefin; The anchor coat layer has a cross-sectional composite elastic modulus in the range of 3.5 to 6.5 GPa and a thickness in the range of 0.4 to 3.0 μm; The first base layer has a layer structure including a skin layer in contact with the anchor coat layer and a core layer, The anchor coat layer has a cross-sectional hardness in the range of 200 MPa or more and 350 MPa or less, and the skin layer has a cross-sectional hardness of 150 MPa or less.

12. A coating composition comprising a first substrate layer, an anchor coat layer, and an inorganic barrier layer in this order; the first substrate layer comprises a polyolefin; The anchor coat layer is a cured film of an anchor coat agent containing a polyurethane resin and a curing agent, and the solid mass ratio of the polyurethane resin to the curing agent in the anchor coat agent [curing agent / polyurethane resin] is within a range of 30 / 100 to 50 / 100, the cross-sectional composite elastic modulus is within a range of 3.5 to 6.5 GPa, and the thickness is within a range of 0.4 to 3.0 μm.

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