Article

Abstract

A product provided with a packaging body provided with a multilayer structure, and a content contained in the packaging body and having a sodium chloride content of 1 mass% or more, the multilayer structure has a barrier layer (A) containing EVOH (a) as a main component, an inorganic vapor deposition layer (B) laminated on the barrier layer (A) and having an average thickness of 7-100 nm, and a heat seal layer (E) containing a polyolefin (e) as a main component, the heat seal layer (E) being the outermost layer of the barrier layer (A) on the opposite side from the side on which the inorganic vapor deposition layer (B) is laminated. The total average thickness of the layers containing the polyolefin resin as the main component laminated on the opposite side of the barrier layer (A) from the side on which the inorganic vapor deposition layer (B) is laminated is 45 [mu] m or more, and the heat sealing layer (E) is positioned on the inner surface side of the package.

Description

Technical Field

[0001] This invention relates to articles having a packaging body and contents. Background Technology

[0002] For packaging materials used for long-term food preservation, gas barrier properties, especially oxygen barrier properties, are generally required. By using packaging materials with high gas barrier properties, it is possible to inhibit the oxidative deterioration of food and / or the growth of microorganisms caused by oxygen intrusion. As layers that enhance gas barrier properties, metal foils or metal vapor-deposited layers such as aluminum, and inorganic oxide vapor-deposited layers such as silicon dioxide and aluminum oxide are widely used. On the other hand, resin layers with gas barrier properties, such as vinyl alcohol polymers and polyvinylidene chloride, are also widely used. Vinyl alcohol polymers exhibit gas barrier properties by achieving crystallization and high density through hydrogen bonding of hydroxyl groups in their molecules. Among them, ethylene-vinyl alcohol copolymers (hereinafter sometimes abbreviated as "EVOH") are suitable for melt molding due to their excellent thermal stability. Therefore, with the development of co-extrusion technology, multilayer films with an EVOH layer in the middle layer are widely used as gas barrier packaging materials (Patent Document 1).

[0003] Furthermore, in recent years, driven by environmental and / or waste issues, the demand for so-called post-consumer reuse (hereinafter sometimes abbreviated as reuse) – the recycling and reuse of packaging materials consumed in the market – has been increasing worldwide. Reuse typically involves cutting recycled packaging materials, sorting / cleaning them as needed, and then melt-blending them using an extruder. The resulting granules are then used to manufacture various molded parts. From this perspective, there is a demand for packaging materials to be composed of as few as possible (single-material production), thereby obtaining high-purity and high-quality reusable resins. For this purpose, the demand for barrier films based on polyolefins, which are widely used as packaging materials, is increasing. It has also been proposed to laminate inorganic vapor-deposited layers onto the EVOH layer of a polypropylene-based multilayer film with an EVOH layer, achieving both gas barrier properties and reusability (Patent Document 2).

[0004] Existing technical documents Patent documents Patent Document 1: International Publication No. 2020 / 071513 Patent Document 2: International Publication No. 2020 / 184523. Summary of the Invention

[0005] The problem that the invention aims to solve When packaging materials using a polyolefin-based multilayer structure with an inorganic vapor-deposited layer stacked on an EVOH layer store contents containing sodium chloride, the appearance and gas barrier properties sometimes deteriorate. On the other hand, in order to suppress appearance deterioration, when using stacked aluminum foil instead of an inorganic vapor-deposited layer for packaging materials, it is difficult to uniformly mix with other components during the melt-mixing process during recycling and reuse, making it difficult to maintain a good balance of appearance characteristics, gas barrier properties, and reusability.

[0006] In view of this situation, the object of the present invention is to provide a packaging body obtained by using a polyolefin-based multilayer structure in which an inorganic vapor-deposited layer is stacked on an EVOH layer, which is an article in which the deterioration of appearance and gas barrier properties is suppressed when storing contents containing sodium chloride while maintaining reusability.

[0007] Methods for solving problems According to the present invention, the above-mentioned objective is achieved by providing the following solution.

[0008] [1] An article comprising a packaging body and contents, wherein the packaging body has a multi-layer structure, and the contents are contained within the aforementioned packaging body and the sodium chloride content is 1% by mass or more. The aforementioned multilayer structure comprises: a barrier layer (A) containing ethylene-vinyl alcohol copolymer (a) (hereinafter sometimes abbreviated as "EVOH(a)") as the main component; an inorganic vapor-deposited layer (B) laminated on the barrier layer (A) with an average thickness of 7 nm or more and 100 nm or less; and a heat-sealing layer (E) containing polyolefin (e) as the main component. The heat-sealing layer (E) is the outermost layer of the barrier layer (A) on the side opposite to the side of the laminated inorganic vapor-deposited layer (B). The total average thickness of the layers containing polyolefin resin as the main component laminated on the side of the barrier layer (A) opposite to the side of the laminated inorganic vapor-deposited layer (B) is 45 μm or more. The heat-sealing layer (E) is located on the inner surface side of the aforementioned packaging body. [2] According to the article of [1], the barrier layer (A) is stretched at least along a uniaxial direction; [3] According to the article of [1] or [2], wherein the average thickness of the barrier layer (A) is 0.1 μm or more and 20 μm or less; [4] The article according to any one of [1] to [3], wherein the average thickness of the barrier layer (A) is 5% or less relative to the average thickness of the aforementioned multilayer structure; [5] The article according to any one of [1] to [4], wherein the inorganic vapor-deposited layer (B) is composed of aluminum, aluminum oxide or silicon oxide; [6] The article according to any one of [1] to [5], wherein the average thickness of the heat seal layer (E) is more than 20 μm and less than 200 μm; [7] The article according to any one of [1] to [6], wherein the aforementioned multilayer structure has an adhesive layer (C) containing an adhesive resin (c) as the main component and a polyolefin layer (D) containing a polyolefin (d) as the main component, and has layers consisting of an inorganic vapor-deposited layer (B), a barrier layer (A), an adhesive layer (C), a polyolefin layer (D) and a heat-sealing layer (E) stacked sequentially; [8] According to the article of [7], wherein the barrier layer (A), the adhesive layer (C) and the polyolefin layer (D) are stretched at least along the uniaxial direction; [9] According to the article of [7] or [8], wherein the barrier layer (A), the adhesive layer (C) and the polyolefin layer (D) are co-extruded films;

[10] According to any one of [7] to [9], wherein the resins that are the main components of the polyolefin layer (D) and the heat-sealing layer (E) are of the same resin type;

[11] The product according to any one of [1] to

[10] , wherein the sodium chloride content of the aforementioned contents is 5% by mass or less;

[12] An article according to any one of [1] to

[11] , wherein the aforementioned contents comprise lipids;

[13] According to the product of

[12] , wherein the lipid content of the aforementioned contents is 95% by mass or less;

[14] According to the product of

[12] or

[13] , wherein the aforementioned lipid comprises triglycerides as the main component.

[0009] Invention Effects According to the present invention, a packaging body obtained by using a polyolefin-based multilayer structure with an inorganic vapor-deposited layer laminated on the surface of an EVOH layer can be provided. This packaging body maintains reusability and suppresses deterioration of appearance and gas barrier properties when storing contents containing sodium chloride. Here, "reusability" as used in this specification means that when a recycled composition is manufactured by melt-blending the recycled material of the packaging body of the article of the present invention, resin gelation is suppressed, and a recycled composition with excellent appearance can be effectively manufactured, which can be evaluated by the reusability tests described in the examples. Detailed Implementation

[0010] The following describes embodiments of the present invention. It should be noted that in the following description, specific materials (compounds, etc.) are sometimes exemplified as materials exhibiting specific functions, but the present invention is not limited to the manner in which such materials are used. Furthermore, the exemplified materials can be used alone or in combination unless otherwise specified.

[0011] The article of the present invention comprises a packaging body and contents. The packaging body has a multi-layer structure, and the contents are housed within the packaging body and contain sodium chloride at a content of 1% by mass or more. The multi-layer structure comprises: a barrier layer (A) containing EVOH (a) as a main component; an inorganic vapor-deposited layer (B) laminated on the barrier layer (A) with an average thickness of 7 nm or more and 100 nm or less; and a heat-sealing layer (E) containing polyolefin (e) as a main component. The heat-sealing layer (E) is the outermost layer of the barrier layer (A) on the side opposite to the side where the inorganic vapor-deposited layer (B) is laminated. The total average thickness of the layers containing polyolefin resin as a main component laminated on the side of the barrier layer (A) opposite to the side where the inorganic vapor-deposited layer (B) is laminated is 45 μm or more. The heat-sealing layer (E) is located on the inner surface side of the packaging body. Here, the barrier layer (A) and the inorganic vapor-deposited layer (B) can be directly laminated or laminated with the aid of other layers such as an adhesive layer. Furthermore, the heat-sealing layer (E) that is the outermost layer in the multilayer structure refers to the heat-sealing layer (E) that is exposed on the surface. Additionally, "the average thickness of the layers containing polyolefin resin as the main component stacked on the side of the barrier layer (A) opposite to the side of the stacked inorganic vapor-deposited layer (B) is 45 μm or more" means that among the layers stacked on the side of the barrier layer (A) opposite to the side of the stacked inorganic vapor-deposited layer (B), the average thickness of each layer containing polyolefin resin as the main component is 45 μm or more, excluding the possibility that other layers are included on the side of the barrier layer (A) opposite to the side of the stacked inorganic vapor-deposited layer (B).

[0012] The multilayer structure of the product of the present invention exhibits a tendency to maintain reusability and excellent gas barrier properties by having a barrier layer (A) containing EVOH(a) as the main component. Furthermore, by depositing an inorganic vapor-deposited layer (B) with an average thickness of 7 nm or more and 100 nm or less on the barrier layer (A), excellent gas barrier properties are also exhibited. Additionally, by ensuring that the total average thickness of the layers containing a polyolefin resin as the main component, deposited on the side of the barrier layer (A) opposite to the side where the inorganic vapor-deposited layer (B) is deposited, is 45 μm or more, the product exhibits a tendency to suppress deterioration of appearance and gas barrier properties even when the contents of the packaging contain 1% or more sodium chloride.

[0013] It should be noted that in this application specification, "main component" refers to a component containing more than 50% by mass.

[0014] Unless otherwise specified, the "average thickness" of each layer refers to the average thickness measured at any 5 locations.

[0015] "ppm" refers to the content of a quality standard (mass ppm).

[0016] "Polyethylene" refers to: homopolymers of ethylene, copolymers of 80 mol% or more of ethylene with less than 20 mol% of α-olefin monomers, and copolymers of 90 mol% or more of ethylene with less than 10 mol% of non-olefin monomers whose functional groups do not contain atoms other than carbon, oxygen and hydrogen atoms.

[0017] "Polypropylene" refers to: homopolymers of propylene, copolymers of propylene with more than 80 mol% and α-olefin monomers with less than 20 mol% and copolymers of propylene with more than 90 mol% and non-olefin monomers whose functional groups do not contain atoms other than carbon, oxygen and hydrogen atoms and are less than 10 mol%.

[0018] "Acid-modified polyethylene" refers to a polymer obtained by modifying polyethylene with an acid. Acid-modified polyethylene can be a polymer in which at least one of an acidic group and an anhydride group is introduced into polyethylene.

[0019] "Acid-modified polypropylene" refers to a polymer obtained by modifying polypropylene with an acid. Acid-modified polypropylene can be a polymer in which at least one of an acidic group and an anhydride group is introduced into polypropylene.

[0020] "Polyolefin" refers to: homopolymers or copolymers of one or more α-olefin monomers, and copolymers of one or more α-olefin monomers with functional groups containing no atoms other than carbon, oxygen and hydrogen atoms and less than 10 mol% of non-olefin monomers, with a molar percentage of more than 90 mol% of one or more α-olefin monomers.

[0021] "Acid-modified polyolefins" refer to polymers obtained by modifying polyolefins with acids. Acid-modified polyolefins can be polymers in which at least one of acidic groups and acid anhydride groups is introduced into the polyolefin.

[0022] "Polyolefin resins" refers to polyolefins and modified polyolefins (such as acid-modified polyolefins). Modified polyolefins are polymers obtained by modifying polyolefins.

[0023] Furthermore, the term "surface (or outermost layer)" in multilayer films and / or multilayer structures does not imply a distinction between the front and back surfaces, but rather refers to the exposed surface. That is, multilayer films and / or multilayer structures have two surfaces. Similarly, multilayer films and / or multilayer structures have two outermost layers.

[0024] It should be noted that, in this specification, "consistently composed of only ~" means that optional ingredients are permitted to be included to the extent that they do not affect the effect of the present invention, and "consistently composed of ..." means excluding optional ingredients other than unavoidably included impurities.

[0025] In addition, in this specification, the numerical range recorded using "~" refers to the values ​​recorded before and after "~" as the lower limit and upper limit.

[0026] [Barrier layer (A)] The multilayer structure in the product of the present invention exhibits good gas barrier properties by providing a barrier layer (A) with EVOH(a) as the main component. Furthermore, the barrier layer (A) has good affinity with the inorganic vapor-deposited layer (B), which will be described later. Therefore, when the inorganic vapor-deposited layer (B) is directly stacked on the barrier layer (A), excellent gas barrier properties are further exhibited, particularly showing a tendency to maintain gas barrier properties even under physical stresses such as bending. It should be noted that multiple barrier layers (A) can be provided.

[0027] EVOH(a) is typically obtained by saponifying an ethylene-vinyl ester copolymer obtained by polymerizing ethylene with a vinyl ester. The ethylene unit content of EVOH(a) is preferably 10 mol% or more and 65 mol% or less, more preferably 20 mol% or more and 60 mol%, and even more preferably 25 mol% or more and 55 mol% or less. If the ethylene unit content of EVOH(a) is 10 mol% or more, the melt-forming properties of EVOH(a) are improved. Furthermore, if the ethylene unit content of EVOH(a) is 65 mol% or less, the gas barrier properties of the multilayer structure in the article of the present invention are improved. The ethylene unit content refers to the content (mol%) of ethylene units relative to all monomer units constituting EVOH.

[0028] The degree of saponification of EVOH(a) is preferably 90 mol% or more. The degree of saponification refers to the ratio of the number of ethylene alcohol units in EVOH(a) to the total number of ethylene alcohol units and vinyl ester units. More preferably, the degree of saponification of EVOH(a) is 95 mol% or more, and even more preferably 99 mol% or more. If the degree of saponification is 90 mol% or more, there is a tendency to increase the gas barrier properties of the multilayer structure in the article of the present invention. The upper limit of the degree of saponification of EVOH(a) can be 100 mol%. The ethylene unit content and degree of saponification of EVOH(a) are determined by… 1 The result is determined by H-NMR measurement.

[0029] EVOH(a) can be a mixture of two or more EVOHs with different ethylene unit contents. In this case, the difference in ethylene unit content between the EVOHs with the largest difference in ethylene unit content is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 15 mol% or less, and can be 3 mol% or more. Similarly, EVOH(a) can be a mixture of two or more EVOHs with different degrees of saponification. In this case, the difference in degree of saponification between the EVOHs with the largest difference in ethylene unit content is preferably 7 mol% or less, more preferably 5 mol% or less, and can be 0.5 mol% or more.

[0030] In EVOH(a), other monomer units besides ethylene units, vinyl ester units, and vinyl alcohol units may be contained, provided that the effects of the present invention are not impaired. In particular, by introducing modifying groups containing primary hydroxyl groups having specific structures, it is sometimes possible to achieve a high level of both gas barrier properties and molding processability of EVOH(a). The content of other monomer units is preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 1% by mass or less, and particularly preferably substantially absent. Other examples of such monomers include olefins such as propylene, butene, pentene, and hexene; 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diacyloxy-2-methyl-1-butene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diacyloxy-1-pentene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6-acyloxy-1-hexene, and 5,6-diacyloxy-1-hexene. Alkenes with ester groups, such as 1,3-diacetoxy-2-methylenepropane, or their saponifications; unsaturated acids, such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, or their anhydrides, salts, or monoalkyl or dialkyl esters; nitriles, such as acrylonitrile and methacrylonitrile; amides, such as acrylamide and methacrylamide; olefin sulfonic acids, such as vinyl sulfonic acid, allyl sulfonic acid, and methyl allyl sulfonic acid, or their salts; vinyl silane compounds, such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxy-ethoxy)silane, and γ-methacryloyloxypropylmethoxysilane; alkyl vinyl ethers, vinyl ketones, N-vinylpyrrolidone, vinyl chloride, vinylidene chloride, etc.

[0031] EVOH(a) can be post-modified by methods such as carbamate, acetalization, cyanoethylation, and oxoalkylation.

[0032] The melt flow rate (MFR) of EVOH(a) as measured according to JIS K7210 (2014) (at 210°C and 2.16 kg load) is preferably 0.2 to 30 g / 10 min. The MFR of EVOH(a) is more preferably 1.0 g / 10 min or more, further preferably 5.0 g / 10 min or more, and particularly preferably 10 g / 10 min or more. On the other hand, the MFR of EVOH(a) is more preferably 25 g / 10 min or less, and further preferably 20 g / 10 min or less.

[0033] (Other compounds) The barrier layer (A) may contain other compounds besides EVOH (a) without impairing the effects of the present invention. Examples of such other compounds include carboxylic acid compounds, phosphoric acid compounds, boron compounds, metal salts (alkali metal salts, alkaline earth metal salts, etc.), antioxidants, ultraviolet absorbers, plasticizers, lubricants, fillers, antistatic agents, etc. The content of the aforementioned other compounds in the barrier layer (A) is generally 5% by mass or less, preferably 2% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less. From the viewpoint of suppressing particulate matter and coloring when the pulverized material containing the barrier layer (A) is melt-molded, it is preferable to include alkali metal ions, carboxylic acid compounds, and / or phosphoric acid compounds. In addition, by including boron compounds, the melt viscosity of the barrier layer (A) and the pulverized material containing the barrier layer (A) can be controlled.

[0034] The carboxylic acid compound can be a monocarboxylic acid, a polycarboxylic acid, or a combination thereof. The carboxylic acid compound can be an ion, which can form a salt with a metal ion. The content of carboxylic acid and carboxylic acid ions in the barrier layer (A) is preferably 50 to 400 ppm. Aliphatic carboxylic acids such as acetic acid and stearic acid are suitable as carboxylic acid compounds. If the barrier layer (A) contains a carboxylic acid compound, it tends to prevent coloring during melt molding.

[0035] The phosphoric acid compound is not particularly limited, and various acids such as phosphoric acid and phosphorous acid and / or their salts can be used. As a phosphate, it can be contained in the form of dihydrogen phosphate, hydrogen phosphate, or phosphate, with dihydrogen phosphate being preferred. The type of cation is not particularly limited, but an alkali metal salt is preferred. Sodium dihydrogen phosphate and potassium dihydrogen phosphate are preferred. When the barrier layer (A) contains a phosphoric acid compound, the content of the phosphoric acid compound in the barrier layer (A), calculated in terms of phosphate ions, is preferably 5 to 100 ppm. If the content of the phosphoric acid compound is 5 ppm or more, there is a tendency for improved colorfastness during melt molding. On the other hand, if the content of the phosphoric acid compound is 100 ppm or less, there is a tendency for improved melt moldability.

[0036] The boron compound is not particularly limited and can include boric acids, borate esters, borates, boron hydrides, etc. Specifically, boric acids include orthoboric acid, metaboric acid, tetraboric acid, etc.; borate esters include triethyl borate, trimethyl borate, etc.; and borates include alkali metal salts, alkaline earth metal salts, borax, etc. of the aforementioned boric acids. Among these compounds, orthoboric acid (hereinafter sometimes abbreviated as boric acid) is preferred. When the barrier layer (A) contains a boron compound, the content of the boron compound in the barrier layer (A) is preferably 50 to 400 ppm in terms of boron element content. If the content of the boron compound is 50 ppm or more, it tends to suppress torque variation during heating and melting. On the other hand, if the content of the boron compound is 400 ppm or less, it tends to maintain good moldability.

[0037] The type of cation in the alkali metal salt is not particularly limited, and sodium or potassium salts are suitable. The type of anion in the alkali metal salt is also not particularly limited. It can be added in the form of carboxylates, carbonates, bicarbonates, phosphates, hydrogen phosphates, borates, hydroxides, etc. When the barrier layer (A) contains an alkali metal salt, the content of the alkali metal salt in the barrier layer (A) is preferably 40 to 500 ppm in terms of metal element conversion. If the content of the alkali metal salt is 40 ppm or more, there is a tendency for good interlayer adhesion. On the other hand, if the content of the alkali metal salt is 500 ppm or less, there is a tendency for excellent melt stability.

[0038] The type of cation in the alkaline earth metal salt is not particularly limited, but magnesium or calcium salts are suitable. The type of anion in the alkaline earth metal salt is also not particularly limited. It can be added in the form of carboxylates, carbonates, bicarbonates, phosphates, hydrogen phosphates, borates, hydroxides, etc. The content of the alkaline earth metal salt in the barrier layer (A) is preferably 10 to 300 ppm. If the barrier layer (A) contains an alkaline earth metal salt, it tends to suppress deterioration during repeated melting and molding of the molded body and / or suppress the formation of deteriorating substances such as gels. Furthermore, multivalent metal salts such as zinc salts are preferred instead of alkaline earth metal salts.

[0039] The following substances can be used as antioxidants, ultraviolet absorbers, plasticizers, lubricants, fillers, and antistatic agents.

[0040] Antioxidants: 2,5-di-tert-butylhydroquinone, 2,6-di-tert-butyl-p-cresol, 4,4'-thiobis(6-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), octadecyl 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, 4,4'-thiobis(6-tert-butylphenol), etc.

[0041] Ultraviolet absorbers: 2-cyano-3,3'-diphenylacrylate ethylene ester, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, etc.

[0042] Plasticizers: dimethyl phthalate, diethyl phthalate, dioctyl phthalate, waxes, liquid paraffin, phosphate esters, etc.

[0043] Lubricants: stearamide, oleamide, erucamide, behenamide, vinyl bis-stearamide, hydroxymethyl stearamide, N-oleopalmitamide, N-stearoerucamide, liquid paraffin, natural paraffin, synthetic paraffin, polyolefin wax, stearyl alcohol, lauryl alcohol, stearic acid, lauric acid, myristic acid, behenic acid, lignite acid, stearyl stearate, stearyl laurate, calcium stearate, magnesium stearate, zinc stearate, lead stearate, etc.

[0044] Fillers: glass fiber, asbestos, wollastonite, calcium silicate, etc.

[0045] Antistatic agents: glycerol monofatty acid esters, fatty acid diethanolamides, alkyl diethanolamines, alkyl sulfonates, alkyl benzene sulfonates, alkyl trimethylammonium salts, alkyl benzyl dimethylammonium salts, alkyl betaine, alkyl imidazoline betaine, etc.

[0046] The barrier layer (A) may also contain thermoplastic resins other than EVOH (a). Examples of thermoplastic resins other than EVOH (a) include various polyolefins (polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymers, copolymers of ethylene with α-olefins having 4 or more carbon atoms, copolymers of polyolefins with maleic anhydride, ethylene-vinyl ester copolymers, ethylene-acrylate copolymers, or modified polyolefins obtained by grafting them with unsaturated carboxylic acids or their derivatives), various polyamides (nylon 6, nylon 6.6, nylon 6 / 66 copolymers, nylon 11, nylon 12, poly(m-phenylene adipamide), etc.), various polyesters (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate), polyvinyl chloride, polyvinylidene chloride, polystyrene, polyacrylonitrile, polyurethane, polycarbonate, polyacetal, polyacrylate, and modified polyvinyl alcohol resins, etc. The content of the aforementioned thermoplastic resin in the barrier layer (A) is generally less than 40% by mass, preferably less than 30% by mass, more preferably less than 20% by mass, even more preferably less than 10% by mass, may be less than 5% by mass, may be less than 1% by mass, and is particularly preferably substantially free of it.

[0047] From the viewpoint of maximizing the effects of the present invention, the proportion of EVOH(a) in the resin constituting the barrier layer (A) is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and can be 98% by mass or more, or 99% by mass or more. The resin constituting the barrier layer (A) can be substantially composed solely of EVOH(a). Furthermore, from the viewpoint of maximizing the effects of the present invention, the proportion of EVOH(a) in the barrier layer (A) is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and can be 98% by mass or more, or 99% by mass or more. The barrier layer (A) can be substantially composed solely of EVOH(a). The upper limit of the proportion of EVOH(a) in the barrier layer (A) can be 100% by mass.

[0048] The barrier layer (A) is preferably stretched at least along a uniaxial direction. That is, the barrier layer (A) is preferably stretched uniaxially or biaxially. When the barrier layer (A) is a stretched layer, especially when it is a biaxially stretched layer, even a relatively thin barrier layer (A) can have good gas barrier properties.

[0049] When the barrier layer (A) is a stretched layer, it is preferable, for example, to be stretched by at least 2 times and less than 12 times along the uniaxial direction, and more preferably by at least 3 times and less than 6 times along the uniaxial direction. In addition, the barrier layer (A) is also preferably stretched by at least 2 times and less than 12 times along the biaxial direction, and more preferably by at least 3 times and less than 6 times along the biaxial direction.

[0050] The lower limit of the average thickness of the barrier layer (A) is preferably 0.1 μm, more preferably 0.3 μm. By making the average thickness of the barrier layer (A) above or above the above lower limit, gas barrier properties can be improved. The upper limit of the average thickness of the barrier layer (A) is preferably 20 μm, more preferably 15 μm, and can be 10 μm, 5 μm, 3 μm, 2 μm or 1 μm. By making the average thickness of the barrier layer (A) below or below the above upper limit, thin-film and lightweight multilayer structures can be achieved.

[0051] The oxygen permeability of the barrier layer (A) is preferably 50 mL·20 μm / (m 2 ·day·atm) or less, more preferably 10mL·20μm / (m 2 ·day·atm) or less, more preferably 5mL·20μm / (m 2 Below 1 mL·20 μm / (m·day), particularly preferred is 1 mL·20 μm / (m·day).2 • Days • atm) or less. Here, oxygen permeability is the value measured at 20°C and 65%RH according to the method described in ISO 14663-2 Annex C (1999).

[0052] The barrier layer (A) can be formed from a single layer or from multiple layers.

[0053] The barrier layer (A) can be a resin film. There are no particular limitations on the manufacturing method of the resin film having the barrier layer (A), and examples include melt processing, solution processing, and calendering, among which melt processing is preferred. Examples of melt processing include casting and blow molding, among which casting is preferred. Alternatively, a stretched film that has been stretched using known methods can also be used.

[0054] The method for manufacturing the raw material, i.e., the resin composition, for forming the barrier layer (A) is not particularly limited, and it can be manufactured by melt-blending EVOH (a) with other components as needed. The components can be directly blended in solid form such as powder or in the form of a melt, or in the form of a solute contained in a solution or a dispersed phase contained in a dispersion. As solutions and dispersions, aqueous solutions and aqueous dispersions are suitable, respectively. Melt blending can be performed using known mixing or blending equipment such as KNEADER-RUDER, extruders, open mill rolls, and Banbury mixers. The temperature range during melt blending can be appropriately adjusted according to the melting point of the EVOH (a) and / or each component used, and is typically 150~250°C. Alternatively, it can be manufactured by pre-adding several components to EVOH (a) and adding other components necessary for melt blending as described above. As a method of pre-adding several components to EVOH (a), EVOH (a) is impregnated in a solution containing dissolved additives in the form of granules or powder.

[0055] [Inorganic vapor deposition layer (B)] The multilayer structure of the present invention includes an inorganic vapor-deposited layer (B) with an average thickness of 7 nm or more and 100 nm or less, stacked on a barrier layer (A). Here, other layers such as an adhesive layer may be provided between the barrier layer (A) and the inorganic vapor-deposited layer (B), or they may be directly stacked; preferably, the barrier layer (A) and the inorganic vapor-deposited layer (B) are directly stacked. By having an inorganic vapor-deposited layer (B) on the barrier layer (A), it tends to exhibit good barrier properties. The inorganic vapor-deposited layer (B) can be formed by vapor-depositing an inorganic material. Examples of inorganic materials include metals (e.g., aluminum), metal oxides (e.g., silicon oxide, aluminum oxide), metal nitrides (e.g., silicon nitride), metal oxynitrides (e.g., silicon oxynitride), or metal carbonitrides (e.g., silicon carbonitride). From the viewpoint of industrial productivity, an inorganic vapor-deposited layer (B) formed of aluminum, alumina, silicon oxide, magnesium oxide, or silicon nitride is preferred, and an inorganic vapor-deposited layer (B) composed of aluminum, alumina, or silicon oxide is more preferred. As a packaging material, aluminum is preferred in the case of providing light-shielding properties. From the viewpoint of the recognizability of the contents of the packaging material and / or microwave oven applicability, alumina or silicon oxide is preferred. It should be noted that even aluminum metal vapor-deposited layers sometimes undergo irreversible oxidation, resulting in the localization of alumina. When the metal vapor-deposited layer locally contains alumina, the ratio (Omol / Almol) of the amount of oxygen atoms constituting the metal vapor-deposited layer is preferably 0.5 or less, more preferably 0.3 or less, further preferably 0.1 or less, and particularly preferably 0.05 or less.

[0056] There are no particular limitations on the formation methods of inorganic vapor deposition layers (B). Examples include physical vapor deposition methods such as vacuum evaporation (e.g., resistance heating evaporation, electron beam evaporation, molecular beam epitaxy, etc.), sputtering, and ion plating; chemical vapor deposition methods such as thermochemical vapor deposition (e.g., catalyst chemical vapor deposition), photochemical vapor deposition, plasma chemical vapor deposition (e.g., capacitively coupled plasma, inductively coupled plasma, surface wave plasma, electron cyclotron resonance, dual magnetron, atomic layer stacking, etc.), and organometallic vapor deposition.

[0057] The average thickness of the inorganic vapor-deposited layer (B) is 7 nm or more and 100 nm or less. Preferably, the average thickness of the inorganic vapor-deposited layer (B) is 15 nm or more, more preferably 30 nm or more. Preferably, the average thickness of the inorganic vapor-deposited layer (B) is 80 nm or less, more preferably 70 nm or less. It should be noted that the average thickness of the inorganic vapor-deposited layer (B) refers to the average thickness of any 10 points on the cross-section of the inorganic vapor-deposited layer (B) measured using an electron microscope.

[0058] When the inorganic vapor-deposited layer (B) is composed of aluminum, the molar ratio of aluminum to aluminum hydroxide (Al / Al(OH)3) at the center of the inorganic vapor-deposited layer (B) in the depth direction (thickness direction), as measured by a TEM-EDS device, is preferably 1.1 or more, more preferably 1.5 or more, further preferably 2.0 or more, particularly preferably 2.5 or more, and can be 2.6 or more. The above molar ratio preferably remains within the above range even after the storage test described in the examples (storage at 43°C and 50%RH for 200 days). If the above molar ratio is within the above range, there is a tendency to maintain good appearance and oxygen barrier properties. It should be noted that aluminum hydroxide can be considered to be produced by corrosion of aluminum or aluminum oxide due to the influence of sodium chloride and moisture, etc., and the above molar ratio can be used as an indicator of its degree of corrosion.

[0059] [Heat-sealing layer (E)] The multilayer structure in the article of the present invention has a heat-sealing layer (E), which is the outermost layer of the barrier layer (A) on the side opposite to the side of the stacked inorganic vapor-deposited layer (B). Furthermore, in the multilayer structure, the total average thickness of the layers containing polyolefin resin as the main component, stacked on the side of the barrier layer (A) opposite to the side of the stacked inorganic vapor-deposited layer (B), is 45 μm or more. Examples of cases where the total average thickness of the layers containing polyolefin resin as the main component, stacked on the side of the barrier layer (A) opposite to the side of the stacked inorganic vapor-deposited layer (B), is 45 μm or more include: the average thickness of the heat-sealing layer (E) is 45 μm or more; and a polyolefin layer (D) (described later) is provided between the heat-sealing layer (E) and the barrier layer (A), the total average thickness of the polyolefin layer (D) and the average thickness of the heat-sealing layer (E) being 45 μm or more, etc. In this way, by having a layer with a thickness of a certain or greater, primarily composed of polyolefin resin, located further inside the barrier layer (A) (EVOH layer) (towards the heat-sealing layer (E)), there is a tendency to suppress the deterioration of appearance and gas barrier properties even when storing products containing sodium chloride at a content of 1% or more by mass. The reason for this is not yet certain, but it can be predicted that if the average thickness of the polyolefin resin layer located further inside the barrier layer (A) (towards the heat-sealing layer (E)) is less than 45 μm, the inorganic vapor-deposited layer (B) will tend to be affected by the contents, resulting in deterioration of gas barrier properties and appearance. This is due to the fact that the barrier layer (A) is a hydrophilic resin. That is, in order to exhibit high barrier properties, it is desirable to adopt a configuration in which an inorganic vapor-deposited layer (B) is stacked on the barrier layer (A). However, on the other hand, it is difficult to suppress the deterioration of the inorganic vapor-deposited layer (B) caused by the contents. At present, there is a problem in balancing gas barrier properties and maintaining gas barrier properties when storing specific contents. The present invention is the solution to this problem through the research of the inventors.

[0060] Regarding the polyolefin (e) included as a main component in the heat-sealing layer (E), examples include homopolymers or copolymers of polyethylene (linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, etc.), ethylene-propylene copolymers, polypropylene, propylene-α-olefin (α-olefin with 4 to 20 carbon atoms) copolymers, polybutene, polypentene, and other olefins. Polyethylene or polypropylene is preferred, and polypropylene is more preferred. One or more types of polyolefin may be used.

[0061] The proportion of polyolefin (e) in the heat-sealing layer (E) is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and can be 98% by mass or more, or 99% by mass or more. The upper limit of the proportion of polyolefin (e) in the heat-sealing layer (E) can be 100% by mass.

[0062] The heat-sealing layer (E) can be an unstretched layer or a stretched layer. From the viewpoint of good heat-sealing performance, the heat-sealing layer (E) is preferably an unstretched layer.

[0063] The lower limit for the average thickness of the heat-sealing layer (E) is preferably 20 μm, more preferably 30 μm, and even more preferably 40 μm. If the average thickness of the heat-sealing layer (E) is above or above the above lower limit, there is a tendency to suppress the deterioration of appearance and gas barrier properties even after storing the product of the present invention. The upper limit for the average thickness of the heat-sealing layer (E) is preferably 200 μm, more preferably 150 μm, and even more preferably 100 μm. By making the average thickness of the heat-sealing layer (E) below or below the above upper limit, it is possible to achieve thin-film structures of multilayer structures, etc.

[0064] The heat seal layer (E) can be formed from a single layer or from multiple layers.

[0065] The multilayer structure in the article of the present invention may have an adhesive layer (C) comprising an adhesive resin (c) as the main component and a polyolefin layer (D) comprising a polyolefin (d) as the main component. Alternatively, it may be a multilayer structure consisting of layers sequentially stacked as an inorganic vapor-deposited layer (B), a barrier layer (A), an adhesive layer (C), a polyolefin layer (D), and a heat-sealing layer (E). Other layers (e.g., adhesive layers described later) may be present between the layers, preferably directly stacked. By giving the aforementioned multilayer structure this layer configuration, it tends to further suppress the deterioration of appearance and gas barrier properties even after the article of the present invention has been stored, and the reusability of the packaging is improved.

[0066] [Adhesive layer (C)] From the viewpoint of obtaining a multilayer structure with excellent appearance, the multilayer structure in the article of the present invention can have an adhesive layer (C) comprising an adhesive resin (c) as the main component. The adhesive resin (c) is preferably an acid-modified polyolefin, more preferably a carboxylic acid-modified polyolefin formed by graft polymerization of unsaturated carboxylic acids such as maleic anhydride or their derivatives onto a polyolefin. The melting point of the adhesive resin (c) depends primarily on the polyolefin before carboxylic acid modification. Regarding this polyolefin, the description of the polyolefin (e) described above can be directly applied. The adhesive resin (c) is preferably acid-modified polyethylene or acid-modified polypropylene, more preferably acid-modified polypropylene. It should be noted that when the main component of the adhesive layer (C), i.e., the adhesive resin (c), is an acid-modified polyolefin, the adhesive layer (C) is a layer comprising a polyolefin-based resin as the main component.

[0067] The proportion of acid-modified polyolefin in the adhesive resin (c) is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 95% by mass or more, and it can be substantially composed of only acid-modified polyolefin. Furthermore, the proportion of adhesive resin (c) in the adhesive layer (C) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 95% by mass or more, and can be 97% by mass or more, or 99% by mass or more, and it can be substantially composed of only adhesive resin (c). The upper limit of the proportion of adhesive resin (c) in the adhesive layer (C) can be 100% by mass.

[0068] [Polyolefin layer (D)] From the viewpoint of improving water vapor barrier properties and bending resistance, and from the viewpoint of suppressing the decrease in appearance and gas barrier properties of the article of the present invention after storage, the multilayer structure in the article of the present invention may have a polyolefin layer (D).

[0069] The polyolefin layer (D) contains polyolefin (d) as the main component. As polyolefin (d), the same substance as that described as polyolefin (e) above can be used, and the method of suitability is also the same as that of suitability of polyolefin (e) above.

[0070] The content of polyolefin (d) in the polyolefin layer (D) is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 97% by mass or more, and can be 99% by mass or more. The maximum content of polyolefin (d) in the polyolefin layer (D) can be 100% by mass.

[0071] The polyolefin layer (D) can be an unstretched layer or a stretched layer. From the viewpoint of further suppressing the deterioration of appearance and gas barrier properties when storing contents containing sodium chloride, it is preferable that it is stretched at least along a uniaxial direction, and more preferably along a biaxial direction.

[0072] The lower limit for the average thickness of each polyolefin layer (D) is preferably 1 μm, more preferably 5 μm. By making the average thickness of the polyolefin layer (D) above or above the above lower limit, sufficient moisture resistance and the like can be achieved. The upper limit for the average thickness of each polyolefin layer (D) is preferably 100 μm, more preferably 50 μm, even more preferably 40 μm, and can be 30 μm. By making the average thickness of the polyolefin layer (D) below or below the above upper limit, the thin film form of the multilayer structure can be achieved.

[0073] The polyolefin layer (D) can be formed from a single layer or from multiple layers.

[0074] In the multilayer structure of the present invention, the polyolefin layer (D') can be provided as the outermost layer on the side opposite to the heat-sealing layer (E). When the multilayer structure has a polyolefin layer (D') as its outermost layer, from the viewpoint of increasing the melting point difference with the heat-sealing layer (E) and improving heat-sealing properties, the polyolefin layer (D') is preferably a stretched layer. The polyolefin layer (D') is a layer containing polyolefin as its main component. The specific and suitable form of the average thickness of the polyolefin contained in the polyolefin layer (D') and the average thickness of the polyolefin layer (D) are the same as those of the polyolefin (d) contained in the polyolefin layer (D) and the polyolefin layer (D) described above. The polyolefin (d) contained in the polyolefin layer (D) and the polyolefin contained in the polyolefin layer (D') can be the same or different. Furthermore, the average thickness of the polyolefin layer and the average thickness of the polyolefin layer (D') can be the same or different.

[0075] The adhesive layer (C), polyolefin layer (D), polyolefin layer (D'), and heat-sealing layer (E) may contain antioxidants, plasticizers, heat stabilizers (melt stabilizers), photoinitiators, deodorizers, ultraviolet absorbers, antistatic agents, lubricants, colorants, fillers, desiccants, pigments, dyes, processing aids, flame retardants, antifogging agents, and other components, provided that such inclusions do not impair the effects of the present invention. The total amount of these components relative to each layer is less than 50% by mass, preferably less than 40% by mass, more preferably less than 30% by mass, further preferably less than 20% by mass, particularly preferably less than 10% by mass, and may be less than 5% by mass, less than 3% by mass, or less than 1% by mass.

[0076] The barrier layer (A), adhesive layer (C), and polyolefin layer (D) are preferably stretched at least along a uniaxial direction, and more preferably along a biaxial direction. This reduces appearance deterioration after storage testing and reduces oxygen barrier degradation after storage testing. When the barrier layer (A), adhesive layer (C), and polyolefin layer (D) are uniaxially stretched, it is preferable to stretch them at least 2 times and less than 12 times along the uniaxial direction, and more preferably 3 times and less than 6 times. Furthermore, when the barrier layer (A), adhesive layer (C), and polyolefin layer (D) are biaxially stretched, it is preferable to stretch them at least 2 times and less than 10 times along the longitudinal axis and at least 2 times and less than 15 times along the transverse axis, and more preferably at least 3 times and less than 6 times along the longitudinal axis and at least 6 times and less than 12 times along the transverse axis.

[0077] The barrier layer (A), adhesive layer (C), and polyolefin layer (D) are preferably stretched integrally. For example, the film can be formed and stretched in the form of a multilayer film in which the barrier layer (A), adhesive layer (C), and polyolefin layer (D) are stacked in sequence.

[0078] The manufacturing method for a multilayer film comprising a barrier layer (A), an adhesive layer (C), and a polyolefin layer (D) is not particularly limited, but co-extrusion is preferred. That is, a multilayer film comprising a barrier layer (A), an adhesive layer (C), and a polyolefin layer (D) is preferably a co-extruded film. The film-forming method for co-extruded films is not particularly limited, and films are typically formed by melt extrusion using an extruder.

[0079] [Multi-layer structure] Regarding the multilayer structure of the article of the present invention, an inorganic vapor-deposited layer (B) is provided on the barrier layer (A), and a heat-sealing layer (E) is provided on the outermost surface of the barrier layer (A) opposite to the surface having the inorganic vapor-deposited layer (B). The total average thickness of the layers comprising a polyolefin resin as the main component, stacked on the side of the barrier layer (A) opposite to the surface having the inorganic vapor-deposited layer (B), is 45 μm or more. Therefore, in the multilayer structure of the article of the present invention, the inorganic vapor-deposited layer (B) is located on the surface opposite to the contents relative to the barrier layer (A). By having the aforementioned multilayer structure have this configuration, it is possible to suppress the deterioration of the appearance and gas barrier properties of the article of the present invention after storage.

[0080] From the viewpoint of maintaining the appearance and gas barrier properties of the product of the present invention at a higher level after storage, the total average thickness of the layer containing a polyolefin resin as the main component, which is laminated on the side opposite to the side of the laminated inorganic vapor-deposited layer (B) of the barrier layer (A), is preferably 60 μm or more, more preferably 80 μm or more. The aforementioned total average thickness may be 150 μm or less, or 120 μm or less.

[0081] From the viewpoint of improving heat-sealing properties, the average thickness of the aforementioned multilayer structure is preferably 250 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less. The average thickness of the aforementioned multilayer structure can be 50 μm or more, or 60 μm or more.

[0082] The ratio of the average thickness of the barrier layer (A) to the average thickness of the aforementioned multilayer structure is preferably 5% or less. If this ratio is 5% or less, there is a tendency for improved reusability. From the viewpoint of further improving reusability, the ratio is more preferably 3% or less, and even more preferably 2% or less. The ratio can be 0.1% or more.

[0083] In the aforementioned multilayer structure, the heat-sealing layer (E) can be laminated using known methods, such as co-extrusion, extrusion coating, and lamination. When using lamination, an adhesive layer, described later, can be provided.

[0084] The aforementioned multilayer structure is not particularly limited, and examples of layer configurations as described below can be given. It should be noted that in the following layer configurations, the barrier layer (A) is referred to as A, the inorganic vapor-deposited layer (B) as B, the heat-sealing layer (E) as E, the adhesive layer (C) as C, the polyolefin layer (D) as D, and the polyolefin layer (D') as D'. " / " indicates direct lamination, and " / / " indicates lamination using an adhesive layer or direct lamination. Regarding " / / ", lamination using an adhesive layer is the preferred method. (1) B / A / / E (2) B / A / C / E (3) B / A / C / D / / E (4) D' / / B / A / / E (5) D' / / B / A / C / E (6) D' / / B / A / C / D / / E From the viewpoint of maintaining industrial productivity, reusability, and further suppressing the deterioration of appearance and gas barrier properties when storing contents containing sodium chloride, D' / / B / A / C / D / / E is preferred.

[0085] From the perspective of improving reusability, the aforementioned multilayer structure preferably does not have a metal layer with an average thickness of more than 1 μm.

[0086] In the aforementioned multilayer structure, from the viewpoint of improving reusability, the resins that are the main components of the polyolefin layer (D) and the heat-sealing layer (E) are preferably the same type of resin. Here, "same type of resin" means, for example, that if the resin included as a main component in the heat-sealing layer (E) is polypropylene, then the resin included as a main component in the polyolefin layer (D) is also polypropylene. Furthermore, in the aforementioned multilayer structure, from the viewpoint of improving reusability, the resins that are the main components of the adhesive layer (C), the polyolefin layer (D), and the heat-sealing layer (E) are also of the same type of resin. Regarding the same type of resin, for example, as long as it is a polypropylene-based resin (polypropylene or modified polypropylene), it is the same type of resin regardless of whether it is modified or not, or the difference in average molecular weight. For example, the resins that are the main components of the adhesive layer (C), the polyolefin layer (D), and the heat-sealing layer (E) are preferably all polypropylene-based resins (polypropylene or modified polypropylene).

[0087] Furthermore, in the multilayer structure, the resins that form the main components of the polyolefin layer (D), the polyolefin layer (D'), and the heat-sealing layer (E) are preferably of the same type, and these resins are more preferably polypropylene-based resins. Additionally, the resins that form the main components of the adhesive layer (C), the polyolefin layer (D), the polyolefin layer (D'), and the heat-sealing layer (E) are preferably of the same type, and these resins are more preferably polypropylene-based resins.

[0088] The layers constituting the aforementioned multilayer structure can be stacked as needed using an adhesive layer. The adhesive layer can be formed by applying a known adhesive and drying it. This adhesive is preferably a two-component reactive polyurethane adhesive, in which a polyisocyanate component and a polyol component are mixed and reacted. The thickness of the adhesive layer is not particularly limited, but is preferably 1 to 5 μm, more preferably 2 to 4 μm.

[0089] The aforementioned multilayer structure may have other layers besides those described above, without impairing the effects of the present invention. Examples of such other layers include, for instance, a printed layer. The printed layer can be present at any location in the multilayer structure of the present invention, preferably on at least one surface of the barrier layer (A). Examples of printed layers include, for instance, a film obtained by coating a solution containing pigments or dyes and, if necessary, a binder resin, and then drying it. As for the coating method for the printed layer, in addition to gravure printing, various coating methods using wire rods, spin coaters, die coaters, etc., are available. The thickness of the printed layer is not particularly limited, but is preferably 0.5 to 10 μm, more preferably 1 to 4 μm.

[0090] Furthermore, the aforementioned multilayer structure may have inorganic vapor-deposited layers other than the inorganic vapor-deposited layer (B), and preferably, the side closer to the contents than the barrier layer (A) does not contain an inorganic vapor-deposited layer. By ensuring that the aforementioned multilayer structure does not contain an inorganic vapor-deposited layer on the side closer to the contents than the barrier layer (A), it tends to further suppress the deterioration of appearance and gas barrier properties after storage.

[0091] [Packaging] The packaging body of the article of the present invention has the aforementioned multi-layer structure and a heat-sealing layer (E) on the inner surface side. In this packaging body, the heat-sealing layer (E) is located on the inner surface side, and the heat-sealing layer (E) can be the innermost layer of the packaging body. The packaging body is preferably obtained by heat-sealing the heat-sealing layers (E) of the aforementioned multi-layer structure together. The packaging body can be formed from the aforementioned multi-layer structure. The packaging body is used for packaging purposes, and its shape is not limited. The packaging body can be in sheet form or formed into a bag or other prescribed shape.

[0092] The packaging material is formed in various forms depending on its purpose, such as stand-up pouches, resealable pouches, soft pouches with spouts, laminated tubing containers, and container lids.

[0093] [Contents] The article of the present invention has contents contained in a packaging body and containing sodium chloride at a content of 1% by mass or more. When the contents contain sodium chloride at a content of 1% by mass or more, there is a tendency to promote the deterioration of the inorganic vapor-deposited layer (B), and sometimes induces deterioration of appearance and gas barrier properties. By using the aforementioned multilayer structure, the deterioration of the inorganic vapor-deposited layer (B) can be suppressed.

[0094] The sodium chloride content in the aforementioned contents is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2.5% by mass or less. If the sodium chloride content is 5% by mass or less, there is a tendency to reduce the deterioration of the appearance and gas barrier properties of the product after storage. The sodium chloride content in the contents can be 1.5% by mass or more. If the sodium chloride content in the contents is 1.5% by mass or more, the problem of the present invention becomes more significant, and the effect of suppressing the deterioration of appearance and gas barrier properties achieved by the multilayer structure in the product of the present invention becomes more significant.

[0095] Furthermore, the present invention becomes more significant when the aforementioned contents contain lipids, and is therefore preferred. When the aforementioned contents contain lipids, their content is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less. When the aforementioned contents contain lipids, their content can be 50% by mass or more, or 60% by mass or more.

[0096] Examples of the aforementioned lipids include monoglycerides, diglycerides, triglycerides, free fatty acids (oleic acid), and sterols. Triglycerides are more preferred. Triglycerides are preferably the main component of the lipid. The lipid may contain one or more types of lipids.

[0097] The aforementioned contents may include water. The amount of water is not particularly limited, but is preferably 5% by mass or more, more preferably 10% by mass or more. When the aforementioned contents contain water, the amount may be 80% by mass or less, or 70% by mass or less.

[0098] Examples of contents containing water include fats such as butter and margarine; condiments such as sauces, ketchup, and mayonnaise. These can be liquids, pastes, or solids. The contents can be food or beverages.

[0099] The articles of the present invention, even when containing contents of 1% or more sodium chloride, can maintain their appearance and gas barrier properties for a long period of time. Furthermore, the same effect is achieved even when the contents contain lipids. Example

[0100] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples at all.

[0101] [Evaluation Method] (1) Preserve the appearance after the experiment The soft-pack bags (15cm square) obtained in the examples and comparative examples were stored for 200 days at 43°C and 50%RH using a constant temperature and humidity apparatus (ESPEC "PR-3J"). The appearance characteristics of the soft-pack bags after 200 days of storage were evaluated according to the following criteria. D was judged as no suppression of whitening.

[0102] Judgment Criteria A: There is almost no noticeable change in appearance compared to before storage. B: Whitening and discoloration were observed in less than 1 / 4 of the soft bag. C: Whitening and discoloration were observed in an area of ​​more than 1 / 4 but less than 1 / 2 of the soft bag. D: Whitening and discoloration were observed in more than 1 / 2 of the soft bag.

[0103] (2) Preservation of OTR (Oxygen permeation rate) after the experiment The flexible bags (15cm square) obtained in the examples and comparative examples were stored for 200 days at 43°C and 50%RH using a constant temperature and humidity device (ESPEC PR-3J). After 200 days of storage, the contents were removed from the bags, and the bags were washed with water. After wiping away moisture, a 50cm² area was cut out from the center of the bags. 2 The circular layer was conditioned for one week at 20°C and 65%RH. Afterward, the outer layer (the side opposite to the heat-sealing layer (E)) was set as the oxygen supply side, and the heat-sealing layer (E) as the carrier gas side, and the oxygen permeation rate was measured. Specifically, an oxygen permeation measuring device (Modern Control's "MOCON OX-TRAN2 / 21") was used to measure the oxygen permeation rate (unit: cc / (m³)) under the following conditions: temperature 20°C, humidity 65%RH on both the oxygen supply and carrier gas sides, oxygen pressure 1 atmosphere, and carrier gas pressure 1 atmosphere. 2 (·day·atm), evaluated according to the following criteria. The carrier gas used is nitrogen containing 2% hydrogen by volume. D is judged as an inability to suppress the reduction in gas barrier properties.

[0104] Judgment Criteria A: 0.1cc / (m 2 • · atm) or more and less than 0.5 cc / (m 2 ·day·atm) B: 0.5cc / (m 2 • · atm) or more and less than 1 cc / (m 2 ·day·atm) C: 1cc / (m 2 ·day·atm) or more and less than 10cc / (m 2 ·day·atm) D: 10cc / (m 2 (Above 1000 ATM)

[0105] (3) Reusability The multilayer structures obtained in the examples and comparative examples were pulverized to a size of 4 mm square or less. The pulverized material was dry-mixed with polypropylene resin (PP1) at a mass ratio (pulverized material / PP1) of 20 / 80, and a monolayer film was formed under the extrusion conditions described below, thereby obtaining a monolayer film with an average thickness of 20 μm. As a control, a control monolayer film with an average thickness of 20 μm was also obtained using only polypropylene resin. Extruder: Single-screw extruder manufactured by Toyo Seiki Co., Ltd. Screw diameter: 20mmφ (L / D=20, compression ratio=3.5, full thread type) Extrusion temperature: C1 / C2 / C3 / D=190 / 230 / 230 / 230℃ Traction roller temperature: 80℃.

[0106] Visually compare the obtained monolayer membrane with the control monolayer membrane and evaluate them according to the following criteria. D indicates poor reusability.

[0107] Judgment Criteria A: Compared with the control, the amount of particulate matter remained almost unchanged. B: Compared with the control, the amount of particles smaller than 0.5 mm was slightly higher. C: Compared with the control, the amount of particulate matter smaller than 0.5 mm increased by more than 30%. D: Compared with the control, the amount of particulate matter larger than 0.5 mm increased by more than 30%.

[0108] (4) The molar ratio of Al to Al(OH)3 in the inorganic vapor-deposited layer (B) The soft-pack bags (15cm square) obtained in the examples and comparative examples were stored for 200 days at 43°C and 50%RH using a constant temperature and humidity apparatus (ESPEC PR-3J). After 200 days of storage, the contents were removed and the bags were washed with water. Cross-sectional slices of the soft-pack bags were then cut using a Leica EM UC7 microtome. The mass ratio of aluminum to oxygen in the depth direction of the inorganic vapor-deposited layer (B) of the cut cross-sections was determined using a TEM (Transmission Electron Microscope)-EDS (Energy Dispersive X-ray Spectroscopy) apparatus (JEOL Ltd., EX-24063JGT). The molar ratio of aluminum to oxygen (Al / O) was calculated based on this mass ratio, and the Al / Al(OH)3 molar ratio in the inorganic vapor-deposited layer was calculated based on this molar ratio.

[0109] [Materials used] EVOH1: EVOH (ethylene content 48 mol%, saponification degree 99.9 mol%, MFR (210℃, 2.16 kg load) 14.8 g / 10 min) PET: PET film (FUTAMURA CHEMICAL "FE2001", average thickness 12μm) MAhPE: Maleic anhydride modified PE (Mitsui Chemicals' "ADMER (trademark) NF518", MFR (2.4 g / 10 min at 190℃ and 2.16 kg load)). MAhPP: Maleic anhydride modified PP (Mitsui Chemicals' "ADMER (trademark) QF500", MFR (230℃, 2.16kg load) 3.0g / 10min) PP1: PP (NOVATEC PP EA7AD manufactured by Nippon Polypropylene Co., Ltd., with a density of 0.90 g / cc and an MFR (at 230°C and 2.16 kg load) of 1.4 g / 10 min). In the examples, it is referred to as BOPP1 when biaxial tension was performed, and as CPP1 when no tension was performed. MDOPE: LDPE (NOVATEC LD LJ400 manufactured by Japan Polypropylene Co., Ltd., with a density of 0.921 g / cc and an MFR (at 190°C and 2.16 kg load) of 1.5 g / 10 min) is referred to as MDOPE when uniaxial tension is performed along the MD direction in the examples. BOPP2: Biaxially stretched PP film ("PYLEN (trademark) film OT P2161" manufactured by Toyobo Co., Ltd., with an average thickness of 20μm) CPP2: Unstretched PP film (Tohcello's "RXC-22", average thickness 70μm) CPP3: Unstretched PP film (Tohcello's "RXC-22", average thickness 50μm) CPP4: An unstretched PP film (average thickness 30μm) obtained by forming PP (NOVATEC PP FX4GF manufactured by Nippon Polypropylene Co., Ltd., with a density of 0.90g / cc and an MFR (at 230℃ and 2.16kg load) of 5.0g / 10min) using a single-screw extruder (Plastics Engineering Research Institute Co., Ltd., GT-32-A). CPP5: An unstretched PP film (average thickness 10μm) obtained by forming PP (NOVATEC PP FX4GF manufactured by Nippon Polypropylene Co., Ltd., with a density of 0.90g / cc and an MFR (at 230℃ and 2.16kg load) of 5.0g / 10min) using a single screw extruder (Plastics Engineering Research Institute Co., Ltd., GT-32-A).

[0110] [Example 1] Using EVOH1, PP1, and MAhPP, three types of three-layer co-extruded films were prepared under the following conditions (EVOH1 / MAhPP / PP1 = 4.5μm / 4.5μm / 180μm). Extruder for EVOH: Single-screw extruder (Toyo Seiki Co., Ltd., ME-type CO-EXT testing machine) EVOH screw: 20mm φ diameter, L / D20, fully threaded screw Extrusion temperatures for EVOH: Feed section / Compression section / Metering section / Die = 175 / 210 / 220 / 230℃ MAhPP extruder: Single screw extruder (TECHNOVEL, SZW20GT-20MG-STD) MAhPP screws: 20mm φ diameter, L / D20, fully threaded screws Extrusion temperature for MAhPP: Feed section / Compression section / Metering section / Die = 150 / 200 / 220 / 230℃ PP extruder: Single screw extruder (Plastics Engineering Research & Development Co., Ltd., GT-32-A) PP screw: 32mm φ diameter, L / D28, fully threaded screw PP extrusion temperature: Feed section / Compression section / Metering section / Die = 170 / 220 / 230 / 230℃ Mold: 300mm wide, 3-layer, 3-type clothes hanger mold (made by the Plastics Engineering Research Institute).

[0111] Using a tenter frame-type simultaneous biaxial stretching device, the obtained co-extruded film was stretched 3 times in the longitudinal direction and 3 times in the transverse direction at 160°C to obtain a biaxially stretched co-extruded film (EVOH1 / MAhPP / BOPP1=0.5μm / 0.5μm / 20μm).

[0112] Using an EWA-105 vacuum evaporator manufactured by Nippon Vacuum Technology Co., Ltd., aluminum was vacuum-deposited onto the surface of the resulting biaxially stretched co-extruded film EVOH1 with an average thickness of 50 nm, thus creating an evaporated film with an aluminum evaporation layer (Al / EVOH1 / MAhPP / BOPP1=50nm / 0.5μm / 0.5μm / 20μm). The resulting evaporated film was evaluated according to the method described in evaluation method (4) above. The results are shown in Table 2. Next, two-component adhesives (Mitsui Chemicals' "TAKELAC (trademark) A-520" and "TAKENATE (trademark) A-50") were coated onto each side of the biaxially stretched polypropylene film (BOPP2) and the unstretched polypropylene film (CPP2) with an average thickness of 2 μm after drying, and allowed to dry to form an adhesive layer (tie). This layer was then laminated with the resulting vapor-deposited film to create a multilayer structure (BOPP2 / tie / Al / EVOH1 / MAhPP / BOPP1 / tie / CPP2=20μm / 2μm / 50nm / 0.5μm / 0.5μm / 20μm / 2μm / 70μm). The reusability of the resulting multilayer structure was evaluated according to the method described in the evaluation method (3) above. The results are shown in Table 2.

[0113] It should be noted that the total average thickness of the layers containing polyolefin resin as the main component, which are stacked on the side opposite to the stacked inorganic vapor-deposited layer (B) of the barrier layer (A) in the obtained multilayer structure, is 90.5 μm.

[0114] Two A4-sized (210mm × 297mm) pieces were cut from the obtained multilayer structure, and CPP2 were overlapped and heat-sealed on three sides to produce a three-way bag (packaging body). Next, edible oil, vinegar, eggs, and salt were mixed to make mayonnaise. The resulting mayonnaise contained 1.9% sodium chloride, 75% lipids, and 15% moisture. 50g of the resulting mayonnaise was filled into the opening of the three-way bag and the opening was heat-sealed to produce a soft bag (product) filled with the contents. The resulting soft bag was evaluated for appearance and OTR (oxygen barrier property) after storage test according to the evaluation methods (1) and (2) described above. The results are shown in Table 2.

[0115] [Examples 2-4, 12, 14; Comparative Examples 1, 2, 4] As described in Table 1, the type and average thickness of the inorganic vapor-deposited layer (B), the average thickness of the polyolefin (PO) layer (D), the type and average thickness of the heat seal (E), and the layer composition were changed. Otherwise, a multilayer structure and a flexible bag were fabricated and evaluated using the same method as in Example 1. The results are shown in Table 2. It should be noted that the evaluation described in the above evaluation method (4) was not performed in Examples 3 and 14.

[0116] [Example 5] A uniaxially stretched co-extruded film prepared under the following conditions was used instead of a biaxially stretched co-extruded film. Otherwise, multilayer structures and flexible bags were prepared and evaluated using the same method as in Example 1. The results are shown in Table 2.

[0117] Three types of three-layer co-extruded films were prepared using EVOH1, PE, and MAhPE under the following conditions (EVOH1 / MAhPE / PE=10μm / 10μm / 100μm). Extruder for EVOH: Single-screw extruder (Toyo Seiki Co., Ltd., ME-type CO-EXT testing machine) EVOH screw: 20mm φ diameter, L / D20, fully threaded screw Extrusion temperatures for EVOH: Feed section / Compression section / Metering section / Die = 175 / 210 / 220 / 230℃ MAhPE extruder: Single screw extruder (TECHNOVEL, SZW20GT-20MG-STD) MAhPE screws: 20mm φ diameter, L / D20, fully threaded screws MAhPP extrusion temperature: Feed section / Compression section / Metering section / Die = 170 / 190 / 210 / 230℃ PE extruder: Single screw extruder (Plastics Engineering Research & Development Co., Ltd., GT-32-A) PE screw: 32mm φ diameter, L / D28, fully threaded screw PE extrusion temperatures: Feed section / Compression section / Metering section / Die = 170 / 190 / 210 / 230℃ Mold: 300mm wide, 3-layer, 3-type clothes hanger mold (made by the Plastics Engineering Research Institute).

[0118] Using a uniaxial stretching device, the obtained co-extruded film was uniaxially stretched 5 times along the longitudinal direction (MD direction) at 115°C to obtain a uniaxially stretched co-extruded film (EVOH1 / MAhPE / MDOPE=2.0μm / 2.0μm / 20μm).

[0119] [Examples 6 and 7] The mayonnaise used as the contents of the soft-pack bag was prepared in the manner described in Table 2, with the proportions of each ingredient adjusted. Otherwise, using the same method as in Example 1, a multi-layered structure and a soft-pack bag were fabricated and evaluated. The results are shown in Table 2.

[0120] [Example 8] As the contents of the flexible bag, 50g of 1.9% by mass saline solution was filled. Otherwise, the multilayer structure and flexible bag were fabricated and evaluated using the same method as in Example 1. The results are shown in Table 1.

[0121] [Example 9] The biaxially stretched EVOH1 film, prepared under the conditions described below, was used instead of the biaxially stretched co-extruded film. Otherwise, multilayer structures and flexible bags were fabricated and evaluated using the same method as in Example 1. The results are shown in Table 2.

[0122] Using a single-screw extruder, EVOH-1 was melted at 240°C and extruded from a die onto a casting roll. Simultaneously, air was blown at a wind speed of 30 m / s using an air knife to obtain an unstretched film with an average thickness of 120 μm. The resulting unstretched film was then contacted with warm water at 80°C for 10 seconds and stretched 3.2 times longitudinally and 3.0 times transversely at 90°C using a tenter frame-type simultaneous biaxial stretching device. Further heat treatment was then performed for 5 seconds in a tenter frame set to 170°C to obtain a biaxially stretched EVOH-1 film with an average thickness of 12 μm.

[0123] [Example 10] The conditions were changed so that the average thickness of the co-extruded film was EVOH1 / MAhPP / PP = 2.0 μm / 2.0 μm / 40 μm. Vapor-deposited films were prepared without stretching. Furthermore, the unstretched polypropylene film for the sealing layer was changed from CPP2 to CPP4. Otherwise, multilayer structures and flexible bags were fabricated and evaluated using the same method as in Example 1. The results are shown in Table 2.

[0124] [Example 11] Without laminating a non-stretched polypropylene film (CPP2), a laminate (BOPP2 / tie / Al / EVOH / MAhPP / BOPP1=20μm / 2μm / 50nm / 0.5μm / 0.5μm / 20μm) was fabricated. A non-stretched polypropylene film (CPP3) was then heat-sealed at 200°C on the surface of BOPP1 in this laminate for 30 seconds to create a multilayer structure. Otherwise, using the same method as in Example 1, multilayer structures and flexible bags were fabricated and evaluated. The results are shown in Table 2.

[0125] [Example 13] By varying the conditions to achieve an average co-extruded film thickness of EVOH1 / MAhPP / PP = 0.5 μm / 0.5 μm / 20 μm, vapor-deposited films were fabricated without stretching. Otherwise, multilayer structures and flexible bags were fabricated and evaluated using the same method as in Example 2. The results are shown in Table 2.

[0126] [Comparative Example 3] A biaxially stretched PET film with an average thickness of 12 μm was used instead of a biaxially stretched co-extruded film. Otherwise, multilayer structures and flexible bags were fabricated and evaluated using the same method as in Example 1. The results are shown in Table 2.

[0127] [Reference Example 1] The mayonnaise used as the filling was prepared and used to contain 0.5% sodium chloride, 75% lipids, and 15% moisture. Otherwise, a multilayer structure and a soft-pack were prepared using the same method as in Example 2, and the results were evaluated. The results are shown in Table 2.

[0128] [Reference Example 2] The mayonnaise used as the filling was prepared and used to produce a mayonnaise containing 0.5% sodium chloride, 75% lipids, and 15% moisture. Otherwise, a multi-layered structure and a soft packaging were prepared using the same method as in Comparative Example 2, and the results were evaluated. The results are shown in Table 2.

[0129] [Reference Example 3] The mayonnaise used as the filling was prepared and used to produce a mayonnaise containing 0.5% sodium chloride, 75% lipids, and 15% moisture. Otherwise, a multi-layered structure and a soft packaging were prepared using the same method as in Comparative Example 1, and the results were evaluated. The results are shown in Table 2.

[0130] [Table 1]

[0131] [Table 2]

[0132] A comparison of Reference Example 1 and Reference Example 2 shows that if the sodium chloride content of the mayonnaise is less than 1% by mass, then even if a heat-sealing layer is included on the side of the barrier layer (A) where the inorganic vapor-deposited layer (B) is stacked, the appearance and gas barrier properties will not deteriorate. A comparison of Reference Example 1 and Reference Example 3 shows that if the sodium chloride content of the mayonnaise is less than 1% by mass, then even if the total average thickness of the layers containing polyolefin resin as the main component, stacked on the side of the barrier layer (A) opposite to the side where the inorganic vapor-deposited layer (B) is stacked, is less than 45 μm, the appearance and gas barrier properties will not deteriorate. Therefore, the deterioration of appearance and gas barrier properties is an unknown problem that has been observed until now when the sodium chloride content is 1% by mass or more and has a specific layer structure. As can be seen from Examples 1 to 14, if the average thickness of the layers containing polyolefin resin as the main component stacked on the side opposite to the stacked inorganic vapor-deposited layer (B) of the barrier layer (A) is 45 μm or more, this problem can be solved.

Claims

1. An article provided with a packaging body having a multilayer structure and a content, the content being housed in the packaging body and having a content of sodium chloride of 1% by mass or more, the multilayer structure having: a barrier layer (A) containing an ethylene-vinyl alcohol copolymer (a) as a main component, an inorganic vapor deposition layer (B) having an average thickness of 7 nm or more and 100 nm or less laminated on the barrier layer (A), and a heat-seal layer (E) containing a polyolefin (e) as a main component, the heat-seal layer (E) being a surface layer on a side of the barrier layer (A) opposite to a side on which the inorganic vapor deposition layer (B) is laminated, a total of the average thicknesses of the layer containing a polyolefin-based resin as a main component laminated on the side of the barrier layer (A) opposite to the side on which the inorganic vapor deposition layer (B) is laminated being 45 μm or more, the heat-seal layer (E) being on an inner surface side of the packaging body.

2. The article of claim 1, wherein, The barrier layer (A) is stretched at least in a uniaxial direction.

3. The article of claim 1 or 2, wherein, The barrier layer (A) has an average thickness of 0.1 μm or more and 20 μm or less.

4. The article of any one of claims 1-3, wherein, A ratio of the average thickness of the barrier layer (A) to an average thickness of the multilayer structure is 5% or less.

5. The article of any one of claims 1-4, wherein, The inorganic vapor deposition layer (B) is composed of aluminum, aluminum oxide, or silicon oxide.

6. The article of any one of claims 1-5, wherein, The heat-seal layer (E) has an average thickness of 20 μm or more and 200 μm or less.

7. The article of any one of claims 1-6, wherein, The multilayer structure has an adhesive layer (C) containing an adhesive resin (c) as a main component and a polyolefin layer (D) containing a polyolefin (d) as a main component, and has a layer configuration in which the inorganic vapor deposition layer (B), the barrier layer (A), the adhesive layer (C), the polyolefin layer (D), and the heat-seal layer (E) are sequentially laminated.

8. The article of claim 7, wherein, The barrier layer (A), the adhesive layer (C), and the polyolefin layer (D) are stretched at least in a uniaxial direction.

9. The article of claim 7 or 8, wherein, The barrier layer (A), the adhesive layer (C), and the polyolefin layer (D) are co-extruded films.

10. The article of any one of claims 7-9, wherein, The resins that become the main components of the polyolefin layer (D) and the heat-seal layer (E) are the same resin type.

11. The article of any one of claims 1-10, wherein, The content of sodium chloride of the content is 5% by mass or less.

12. The article of any one of claims 1-11, wherein, The content contains a lipid.

13. The article of claim 12, wherein, The content of the lipid of the content is 95% by mass or less.

14. The article of claim 12 or 13, wherein, The lipid contains a triglyceride as a main component.

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