Resin film and laminated film

Abstract

To provide a resin film and a laminate film having excellent water vapor permeability, and having excellent gas barrier property even under low humidity environment.SOLUTION: A resin film 2 includes: one or both of polyvinyl alcohol and modified polyvinyl alcohol; and aqueous polyurethane, where [a total content (pts.mass) of the polyvinyl alcohol and the modified polyvinyl alcohol]: [a content (pts.mass) of the aqueous polyurethane is 1: 1 to 1: 9.9, and at least one selected from the group consisting of the polyvinyl alcohol, the modified polyvinyl alcohol, and the aqueous polyurethane has a bridge structure. A laminate film 1 includes a substrate layer 3 on the resin film 2.SELECTED DRAWING: Figure 1

Description

[[Technical Field]]

[0001] The present invention relates to a resin film and a laminated film. [[Background Art]]

[0002] When packaging metal contents such as medical devices, industrial members, and electronic components, it is necessary to dry the contents before packaging to prevent the occurrence of rust or the like on the contents. If the contents are not completely dried, the contents must be dried after packaging, which requires that the film for packaging the contents ensures moisture permeability.

[0003] Conventionally, base films with high moisture permeability are known (for example, Patent Document 1). However, conventional high moisture-permeable base films cannot ensure gas barrier properties, so there is a risk that the contents may deteriorate due to oxidation. Further, in order to prevent deterioration of the contents, it is necessary to fill an inert gas such as carbon dioxide or nitrogen. However, conventional high moisture-permeable base films allow inert gas to permeate therethrough, so the inert gas cannot be filled, making it difficult to prevent deterioration of the packaged contents. [[Prior Art Literature]] [[Patent Literature]]

[0004] [[Patent Document 1]] Japanese Unexamined Patent Application Publication No. 2019-163357 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resin film that, when laminated on a base layer having high moisture permeability, can impart gas barrier properties to the base layer while suppressing a decrease in the moisture permeability of the base layer.

[0006] Furthermore, resin films containing polyvinyl alcohol have the drawback that while they exhibit high moisture permeability in high-humidity environments, their moisture permeability decreases in low-humidity environments. Therefore, the present invention aims to provide a resin film that exhibits high moisture permeability even in low-humidity environments, and has high moisture permeability regardless of the external humidity environment.

[0007] Furthermore, the present invention aims to provide a laminated film that is excellent in both moisture permeability and gas barrier properties. [Means for solving the problem]

[0008] To achieve the above objectives, the present invention employs the following configuration.

[0009] [1] A resin film comprising either or both of polyvinyl alcohol and modified polyvinyl alcohol and aqueous polyurethane, wherein the resin film has a ratio of [total content of polyvinyl alcohol and modified polyvinyl alcohol (parts by mass)] to [content of aqueous polyurethane (parts by mass)] of 1:1 to 1:9.9, and one or more selected from the group consisting of polyvinyl alcohol, modified polyvinyl alcohol, and aqueous polyurethane have a crosslinked structure. [2] The resin film according to [1], comprising a titanium compound in the crosslinked structure. [3] The water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 75%RH, was 5000 g / m². 2 The water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 45%RH, is 1500 g / m². 2 • A resin film described in [1] or [2], which is of day or longer. [4] The resin film described in any one of items [1] to [3], wherein the air resistance of the resin film, measured by the Wang Research method specified in JIS P 8117:2009, under conditions of 23°C and 50%RH, is 5000 seconds or more. [5] A resin film, wherein the water vapor permeability of the resin film at 30°C and 75%RH, as measured by the cup method specified in JIS Z 0208, is 5000 g / m². 2 The water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 45%RH, is 1500 g / m². 2 A resin film having a lifespan of 5,000 seconds or more, and whose air permeability resistance, measured by the Wang Research method specified in JIS P 8117:2009, is 5,000 seconds or more under conditions of 23°C and 50% RH. [6] The resin film according to any one of items [1] to [5], wherein the thickness of the resin film is 0.1 μm or more and 5.0 μm or less. A laminated film comprising a resin film described in any one of items [7][1] to [6], and a base material layer provided on the resin film. [Effects of the Invention]

[0010] The resin film of the present invention comprises either or both of polyvinyl alcohol and modified polyvinyl alcohol, and aqueous polyurethane, wherein the ratio of [total content of polyvinyl alcohol and modified polyvinyl alcohol (parts by mass)] to [content of aqueous polyurethane (parts by mass)] is 1:1 to 1:9.9, and one or more selected from the group consisting of polyvinyl alcohol, modified polyvinyl alcohol, and aqueous polyurethane have a crosslinked structure, thereby suppressing a decrease in the moisture permeability of the substrate layer while imparting gas barrier properties to the substrate layer. Furthermore, it exhibits high moisture permeability in both high-humidity and low-humidity environments, and maintains high moisture permeability regardless of the external humidity environment. Furthermore, the resin film of the present invention, as measured by the cup method specified in JIS Z 0208, has a water vapor permeability of 5000 g / m² under conditions of 30°C and 75% RH. 2 The water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 45%RH, is 1500 g / m². 2 The resistance to air permeability of the resin film is 5000 seconds or more, as measured by the Wang Research method specified in JIS P 8117:2009 under conditions of 23°C and 50%RH. Therefore, it is possible to impart gas barrier properties to the substrate layer while suppressing a decrease in the moisture permeability of the substrate layer. Furthermore, it exhibits high moisture permeability in both high-humidity and low-humidity environments, and maintains high moisture permeability regardless of the external humidity environment.

[0011] Furthermore, the laminated film of the present invention comprises the resin film and a base material layer provided on the resin film, and therefore has excellent moisture permeability and gas barrier properties, and maintains high moisture permeability in both high-humidity and low-humidity environments, and has high moisture permeability regardless of the external humidity environment. [Brief explanation of the drawing]

[0012] [Figure 1] This is a cross-sectional view showing the structure of a laminated film comprising a resin film, which is one embodiment to which the present invention is applied. [Modes for carrying out the invention]

[0013] The following describes in detail a resin film and a laminated film equipped with this resin film, which are embodiments to which the present invention is applied. Note that, for the sake of clarity, the drawings used in the following description may show enlarged versions of key features, and the dimensional ratios of each component may not be the same as those in reality.

[0014] <<Resin film>> ◎First Embodiment First, the properties of the resin film of the first embodiment will be described. The resin film of the first embodiment of the present invention comprises either or both of polyvinyl alcohol and modified polyvinyl alcohol, and aqueous polyurethane, wherein the ratio of [total content of the polyvinyl alcohol and modified polyvinyl alcohol (parts by mass)] to [content of the aqueous polyurethane (parts by mass)] is 1:1 to 1:9.9, and one or more selected from the group consisting of the polyvinyl alcohol, the modified polyvinyl alcohol, and the aqueous polyurethane have a crosslinked structure. The resin film of this embodiment contains either or both of polyvinyl alcohol and modified polyvinyl alcohol, and aqueous polyurethane. In the resin film, the ratio of [total content of polyvinyl alcohol and modified polyvinyl alcohol (parts by mass)] to [content of aqueous polyurethane (parts by mass)] is 1:1 to 1:9.9. One or more elements selected from the group consisting of polyvinyl alcohol, modified polyvinyl alcohol, and aqueous polyurethane have a crosslinked structure. This allows for the suppression of a decrease in the moisture permeability of the substrate layer while imparting gas barrier properties to the substrate layer. Furthermore, it exhibits high moisture permeability in both high-humidity and low-humidity environments, maintaining high moisture permeability regardless of the external humidity environment.

[0015] The resin film of this embodiment, when laminated onto a highly permeable substrate layer, can suppress the decrease in the moisture permeability of the substrate layer in both high-humidity and low-humidity environments, while also providing gas barrier properties to the substrate layer. Therefore, even if the contents are packaged without being completely dried, they can be dried after packaging. Furthermore, because the resin film of this embodiment can provide gas barrier properties to the substrate layer, deterioration of the contents can be prevented by sealing in an inert gas after packaging. For example, metal articles such as medical devices, industrial materials, and electronic components can be packaged without drying and then dried after packaging by sealing in an inert gas, allowing for quick packaging and preventing deterioration due to rust, etc. In this specification, "low humidity environment" means, for example, an environment with a relative humidity of 45% or less; "high humidity environment" means, for example, an environment with a relative humidity of more than 75%; and "medium humidity environment" means, for example, an environment with a relative humidity of more than 45% and 75% or less.

[0016] <Gas barrier resin> The resin film of this embodiment includes a gas barrier resin. Gas barrier resins are resins that suppress the permeation of gases and impart gas barrier properties to the substrate layer. There are no particular restrictions on the type of gas, as long as it does not affect the contents packaged by the laminated film described later; examples include carbon dioxide and nitrogen.

[0017] The resin film of this embodiment includes, as a gas barrier resin, either or both of polyvinyl alcohol and modified polyvinyl alcohol, and aqueous polyurethane.

[0018] Modified polyvinyl alcohols include cationic modified polyvinyl alcohol, anionic modified polyvinyl alcohol, nonionic modified polyvinyl alcohol, and vinyl alcohol polymers. In addition, vinyl acetate resins (e.g., "Exceval" manufactured by Kuraray Co., Ltd.), polyvinyl acetal resins obtained by reacting polyvinyl alcohol with an aldehyde (e.g., "Eslec" manufactured by Sekisui Chemical Co., Ltd.), silanol-modified polyvinyl alcohol having a silanol group (e.g., "R-1130" manufactured by Kuraray Co., Ltd.), modified polyvinyl alcohol resins having an acetoacetyl group in the molecule (e.g., "Gosephymer® Z / WR series" manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and modified polyvinyl alcohol resins having a polyvinylpyrrolidone group in the molecule (e.g., "Pitzcol" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) are also included in modified polyvinyl alcohols.

[0019] Examples of anionic modified polyvinyl alcohols include polyvinyl alcohol having anionic groups as described in Japanese Patent Publication No. 1-206088, copolymers of vinyl alcohol and a vinyl compound having a water-soluble group as described in Japanese Patent Publication Nos. 61-237681 and 63-307979, and modified polyvinyl alcohol having a water-soluble group as described in Japanese Patent Publication No. 7-285265.

[0020] Furthermore, examples of nonionic modified polyvinyl alcohols include polyvinyl alcohol derivatives in which a polyalkylene oxide group is added to a portion of vinyl alcohol, as described in Japanese Patent Publication No. 7-9758 (for example, "Gosenex® WO" manufactured by Mitsubishi Chemical Corporation), block copolymers of vinyl compounds having hydrophobic groups and vinyl alcohol, as described in Japanese Patent Publication No. 8-25795, silanol-modified polyvinyl alcohol having a silanol group, and reactive group-modified polyvinyl alcohol having reactive groups such as acetoacetyl groups, carbonyl groups, and carboxyl groups (for example, "D Polymer" manufactured by Nippon Vivipar Co., Ltd., which is a reactive group-modified polyvinyl alcohol having a carbonyl group).

[0021] Examples of cation-modified polyvinyl alcohols include those described in Japanese Patent Publication No. 61-10483, which have primary to tertiary amino groups or quaternary ammonium groups in the main chain or side chain of the polyvinyl alcohol, and can be obtained by saponifying a copolymer of an ethylenically unsaturated monomer having cationic groups and vinyl acetate.

[0022] Examples of vinyl alcohol-based polymers include Exceval (mentioned above) and Nichigo G Polymer (product name: manufactured by Nippon Synthetic Chemical Industry Co., Ltd.).

[0023] In this specification, aqueous polyurethane refers to polyurethane fine particles with a particle size of 5 to 1000 nm, and is a water-dispersible type of polyurethane. Although polyurethane is normally insoluble in water, aqueous polyurethane can be dispersed in water. The particle size of the polyurethane fine particles is determined by laser diffraction. Examples of polyurethanes include polyester-based, polycarbonate-based, and polyether-based materials. In this specification, "polyester-based polyurethane" means "polyurethane having polyester segments." "Polycarbonate-based polyurethane" means "polyurethane having polycarbonate segments." "Polyether-based polyurethane" means "polyurethane having polyether segments." In terms of enhancing moisture permeability, polyether-based polyurethanes having highly hydrophilic polyether segments in their molecular chains are preferred. Specifically, those having polyether segments such as polyoxyethylene glycol or block copolymers of polyoxyethylene and polyoxypropylene, and with long lengths between urethane bonds, are preferred. Furthermore, to improve moisture permeability, the Tg of the polyurethane is preferably 25°C or lower, more preferably -20°C or lower, and particularly preferably -50°C or lower. Alternatively, as the aqueous polyurethane, a varnish in which aqueous polyurethane is dispersed in water or a mixed solvent of water and an organic solvent may be used. It is preferable to use a water-dispersible type because it does not harm the environment and has the effect of suppressing penetration and erosion into the substrate. Examples of varnishes in which aqueous polyurethane is dispersed include Hydran (product name: manufactured by DIC Corporation).

[0024] The moisture permeability and gas barrier properties of the resin film can be adjusted by adjusting the molecular weight and degree of saponification of polyvinyl alcohol or modified polyvinyl alcohol. The degree of saponification of polyvinyl alcohol or modified polyvinyl alcohol is preferably 70 to 99 mol%, more preferably 85 to 99 mol%, and even more preferably 97 to 99 mol%. If the degree of saponification is above the lower limit, the water resistance increases and it becomes less likely to dissolve when in contact with water, thus maintaining the strength of the film. Furthermore, if the degree of saponification is below the upper limit, it is possible to maintain appropriate water solubility and produce a solution with good coating properties. Furthermore, the viscosity of a 4% by mass solution of polyvinyl alcohol or modified polyvinyl alcohol is preferably 3 mPa·s or higher, more preferably 8.0 mPa·s or higher, and even more preferably 20 mPa·s or higher. Having the above viscosity in a 4% by mass solution of polyvinyl alcohol or modified polyvinyl alcohol results in high water vapor permeability, increased strength, and reduced hygroscopicity. Furthermore, from the viewpoint of coating properties, it is preferable that the viscosity of a 4% by mass solution is 1000 mPa·s or less.

[0025] The polyvinyl alcohol or modified polyvinyl alcohol contained in the resin film may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0026] Furthermore, the aqueous polyurethane contained in the resin film may be of one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0027] In the resin film, the ratio of the content of the gas barrier resin to the total mass of the resin film (([Polyvinyl alcohol content of the resin film (parts by mass)] + [Modified polyvinyl alcohol content of the resin film (parts by mass)] + [Aqueous polyurethane content of the resin film (parts by mass)] + [Crosslinking agent content of the resin film (parts by mass)]) / [Total mass of the resin film (parts by mass)] × 100) is preferably 90% by mass or more, and may be, for example, 95% by mass or more, 97% by mass or more, or 99% by mass or more. When the ratio is above the lower limit, the effect of using the resin is more pronounced, and the gas barrier properties of the resin film are further enhanced. The upper limit of the aforementioned ratio is not particularly limited, and the ratio should be 100% by mass or less.

[0028] In the aforementioned resin film, the ratio of the gas barrier resin content to the total mass of the resin film may be set to a different numerical range in addition to the above-mentioned range, depending on the application of the resin film.

[0029] In the resin film, the ratio of [total content of polyvinyl alcohol and modified polyvinyl alcohol (parts by mass)] to [content of aqueous polyurethane (parts by mass)] is 1:1 to 1:9.9, preferably 1:1 to 1:9, and also 1:1 to 1:8, 1:1 to 1:7, 1:1 to 1:6, 1:1 to 1:5, 1:1 to 1:4, 1:1 to 1:3, 1:1 to 1:2, 1:2 to 1:9.9, 1:2 to 1:9, 1:2 to 1:8, 1:2 to 1:7, 1:2 to 1:6, 1:2 to 1:5, 1:2 to 1:4, 1:2 to 1:3, and 1:3 to 1:9.9. , 1:3~1:9, 1:3~1:8, 1:3~1:7, 1:3~1:6, 1:3~1:5, 1:3~1:4, 1:4~1:9.9, 1:4~1:9, 1:4~1:8, 1:4~1:7, 1:4~1:6, 1:4~1:5, 1:5~1:9.9, 1:5~1:9, 1:5~1:8, 1:5~1:7, 1:5~1:6, 1:6~1:9.9, 1:6~1:9, 1:6~1:8, 1:6~1:7, 1:7~1:9.9, 1:7~1:9, 1:7~1:8, 1:8~1:9.9, and 1:8~1:9 may be any of the above ratios. However, these are just examples of the ratios mentioned above.

[0030] In the resin film, the ratio of [total content of polyvinyl alcohol and modified polyvinyl alcohol (parts by mass)] to [content of aqueous polyurethane (parts by mass)] is within the above range, so that the resin film has high moisture permeability not only in high humidity environments but also in low humidity environments. Furthermore, since the resin composition containing either or both of polyvinyl alcohol and modified polyvinyl alcohol and aqueous polyurethane can be uniformly applied to the surface of the substrate layer, the resin film can be uniformly formed on the substrate layer. The moisture permeability of the resin film in high humidity environments can be evaluated, for example, by the amount of water vapor transmitted under conditions of 30°C and 75%RH, measured by the cup method specified in JIS Z 0208. The moisture permeability of the resin film in low humidity environments can be evaluated by the amount of water vapor transmitted under conditions of 30°C and 45%RH, measured by the cup method specified in JIS Z 0208.

[0031] In the aforementioned resin film, one or more materials selected from the group consisting of polyvinyl alcohol, modified polyvinyl alcohol, and aqueous polyurethane have a crosslinked structure. For example, in the aforementioned resin film, polyvinyl alcohols are crosslinked with each other, modified polyvinyl alcohols with each other, aqueous polyurethanes with each other, polyvinyl alcohol and modified polyvinyl alcohol, polyvinyl alcohol and aqueous polyurethane, or modified polyvinyl alcohol and aqueous polyurethane are crosslinked with each other. In other words, the resin film containing polyvinyl alcohol and aqueous polyurethane, but not modified polyvinyl alcohol, contains one or more selected from the group consisting of crosslinked polyvinyl alcohols, crosslinked aqueous polyurethanes, and crosslinked polyvinyl alcohol and aqueous polyurethane, and may also contain either or both uncrosslinked polyvinyl alcohol and uncrosslinked aqueous polyurethane, or may not contain them. The resin film, which contains modified polyvinyl alcohol and aqueous polyurethane but does not contain polyvinyl alcohol, contains one or more selected from the group consisting of crosslinked products of modified polyvinyl alcohols, crosslinked products of aqueous polyurethanes, and crosslinked products of modified polyvinyl alcohol and aqueous polyurethane, and may further contain either or both of uncrosslinked modified polyvinyl alcohol and uncrosslinked aqueous polyurethane, or may not contain them. The resin film comprising polyvinyl alcohol, modified polyvinyl alcohol, and aqueous polyurethane contains one or more selected from the group consisting of crosslinked polyvinyl alcohols, crosslinked modified polyvinyl alcohols, crosslinked aqueous polyurethanes, crosslinked polyvinyl alcohol and aqueous polyurethane, crosslinked modified polyvinyl alcohol and aqueous polyurethane, and crosslinked polyvinyl alcohol and modified polyvinyl alcohol. Furthermore, it may or may not contain one or more selected from the group consisting of uncrosslinked polyvinyl alcohol, uncrosslinked modified polyvinyl alcohol, and uncrosslinked aqueous polyurethane.

[0032] The aforementioned crosslinked structure can be formed by applying a crosslinking agent to one or more materials selected from the group consisting of polyvinyl alcohol without a crosslinked structure, modified polyvinyl alcohol, and aqueous polyurethane. Having one or more materials selected from the group consisting of polyvinyl alcohol, modified polyvinyl alcohol, and aqueous polyurethane having a crosslinked structure improves the water resistance of the resin film. Furthermore, it is possible to impart gas barrier properties to the substrate layer while suppressing a decrease in the moisture permeability of the substrate layer.

[0033] (Crosslinking agent) The crosslinking agent crosslinks the polyvinyl alcohol, the modified polyvinyl alcohol, and the aqueous polyurethane by reacting with one or more of these selected from the group, or by interacting with them without reacting with them.

[0034] Examples of crosslinking agents include titanium compounds, metal chelate compounds, boron compounds, isocyanate compounds, organic acids, acid-modified polymers, hydrazide compounds, alkylamines, and azo compounds. Examples of titanium compounds include alkoxide titanium compounds and acylate titanium compounds. Examples of hydrazide compounds include adipic acid dihydrazide, sebacate acid dihydrazide, dodecanedihydrazide, isophthalic acid dihydrazide, and salicylic acid hydrazide. Examples of metal chelate compounds include zirconium compounds (for example, "Zircosol AC-7" and "Zircosol ZC-20" manufactured by Daiichi Rare Elements Chemical Industry Co., Ltd.). Examples of organic acids include polycarboxylic acids such as malic acid, maleic acid, citric acid, and succinic acid. In particular, titanium compounds are preferred because they are polyfunctional, highly reactive with the hydroxyl groups of polyvinyl alcohol and modified polyvinyl alcohol, and readily form a varnish at room temperature. Furthermore, they react sufficiently with polyvinyl alcohol and modified polyvinyl alcohol at the temperature at which the varnish is applied to the substrate and dried. In other words, it is preferable that the resin film contains a titanium compound in its crosslinked structure. Here, the titanium compound contained in the crosslinked structure is either the titanium compound itself, which is the crosslinking agent, or a compound (structure) derived from the titanium compound, which is the crosslinking agent. Specific examples of titanium compounds that are crosslinking agents include titanium lactate (for example, "Orgatics TC310" manufactured by Matsumoto Fine Chemical Co., Ltd.) and titanium triethanolamine (for example, "Orgatics TC400" manufactured by Matsumoto Fine Chemical Co., Ltd.).

[0035] The crosslinking agent, which is reacted with one or more selected from the group consisting of the polyvinyl alcohol, the modified polyvinyl alcohol, and the aqueous polyurethane, may be just one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0036] In the aforementioned resin film, the amount of crosslinking agent is preferably 5 to 70% by weight relative to the total amount (parts by mass) of polyvinyl alcohol, modified polyvinyl alcohol, and aqueous polyurethane. For example, when using polyvinyl alcohol or modified polyvinyl alcohol and aqueous polyurethane, and using a titanium compound as the crosslinking agent, the amount of crosslinking agent is preferably 10 to 70% by mass, more preferably 30 to 70% by mass, and even more preferably 50 to 70% by mass, relative to the total amount of polyvinyl alcohol or modified polyvinyl alcohol and aqueous polyurethane. Furthermore, when using modified polyvinyl alcohol and aqueous polyurethane, and using a hydrazide compound as the crosslinking agent, the amount of crosslinking agent is preferably 5 to 20% by mass, relative to the total amount of modified polyvinyl alcohol and aqueous polyurethane.

[0037] The temperature at which a crosslinking agent is applied to one or more materials selected from the group consisting of polyvinyl alcohol, modified polyvinyl alcohol, and aqueous polyurethane (crosslinking temperature) is preferably 70 to 120°C, and more preferably 90 to 110°C. The time for applying the crosslinking agent (crosslinking time) is preferably 0.1 minutes to 2 hours, more preferably 0.2 minutes to 10 minutes, and even more preferably 0.3 minutes to 3 minutes.

[0038] When applying a crosslinking agent to one or more materials selected from the group consisting of polyvinyl alcohol, modified polyvinyl alcohol, and aqueous polyurethane, it is preferable to use a solvent. Examples of the aforementioned solvents include water, ethanol, 2-propanol, and ethyl acetate. The solvent may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose. The crosslinked gas barrier resin is preferably dried to remove the solvent. The drying temperature is preferably 90 to 120°C, and the drying time is preferably 0.2 to 10 minutes, and more preferably 1 to 3 minutes.

[0039] The water vapor transmission rate of the resin film measured by the cup method specified in JIS Z 0208 under the conditions of 30°C and 75% RH is 5000 g / m 2 ·day or more, preferably 5500 g / m 2 ·day or more, more preferably 5600 g / m 2 ·day or more, still more preferably 5700 g / m 2 ·day or more, particularly preferably 5800 g / m 2 ·day or more, 5900 g / m 2 ·day or more, 6000 g / m 2 ·day or more, 7000 g / m 2 ·day or more, 8000 g / m 2 ·day or more, 9000 g / m 2 ·day or more, 10000 g / m 2 ·day or more, and 12000 g / m 2 ·day or more. When the water vapor transmission rate of the resin film measured by the cup method specified in JIS Z 0208 under the conditions of 30°C and 75% RH is not less than the above lower limit, the resin film has high moisture permeability even in a high humidity environment.

[0040] The water vapor transmission rate of the resin film measured by the cup method specified in JIS Z 0208 under the conditions of 30°C and 45% RH is 1500 g / m 2 ·day or more, preferably 2000 g / m 2 ·day or more, more preferably 2500 g / m 2 ·day or more, still more preferably 3000 g / m 2 ·day or more, particularly preferably 3500 g / m 2 ·day or more, 4000 g / m 2 ·day or more, and 5000 g / m 2The duration may be any of the above-mentioned days or longer. The water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 45%RH, is equal to or greater than the above lower limit, thereby providing high moisture permeability even in low humidity environments.

[0041] A preferred resin film in this embodiment is, for example, one in which the water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 75% RH, is preferably 5000 g / m². 2 • More than 5500g / m² 2 • 5600 g / m² or more, more preferably 5600 g / m² 2 • 5700 g / m² or more, especially preferred. 2 • More than 5800 g / m², most preferably 5800 g / m² 2 The film is more than 1500 g / m² and the water vapor transmission rate of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 45% RH, is preferably 1500 g / m². 2 • More than 2500g / m² 2 • 3000 g / m² or more, more preferably 3000 g / m² 2 Examples include resin films with a water vapor permeability of 1 day or more. The water vapor permeability of the resin film measured by the cup method specified in JIS Z 0208 at 30°C and 75%RH, and the water vapor permeability at 30°C and 45%RH, are both above the lower limit, thus the resin film has high moisture permeability in both high-humidity and low-humidity environments, and the resin film has high moisture permeability regardless of the external environment.

[0042] The amount of water vapor transmitted under the above conditions of 30°C and 75%RH, and the amount of water vapor transmitted under the above conditions of 30°C and 45%RH, can be adjusted, for example, by the type or content of the gas barrier resin, or by the thickness of the resin film.

[0043] The air permeability resistance of the resin film, measured by the Wangyan method specified in JIS P 8117:2009, under conditions of 23°C and 50%RH, is preferably 5,000 seconds or more, preferably 100,000 seconds or more, more preferably 1,000,000 seconds or more, and may be any of 2,000,000 seconds or more, 3,000,000 seconds or more, 4,000,000 seconds or more, 5,000,000 seconds or more, 8,000,000 seconds or more, and 10,000,000 seconds or more. The air permeability resistance being above the lower limit provides excellent gas barrier properties. The air permeability resistance can be adjusted, for example, by the type or content of the gas barrier resin, or by the thickness of the resin film.

[0044] A more preferred resin film in this embodiment is, for example, one in which the water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 75% RH, is preferably 5000 g / m². 2 • More than 5500g / m² 2 • 5600 g / m² or more, more preferably 5600 g / m² 2 • 5700 g / m² or more, especially preferred. 2 • More than 5800 g / m², most preferably 5800 g / m² 2 The film is more than 1500 g / m² and the water vapor transmission rate of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 45% RH, is preferably 1500 g / m². 2 • More than 2500g / m² 2 • 3000 g / m² or more, more preferably 3000 g / m² 2 Examples of resin films include those with a lifespan of 1 day or more, and whose air permeability resistance, measured by the Wang Ren method specified in JIS P 8117:2009, under conditions of 23°C and 50% RH, is preferably 5,000 seconds or more, more preferably 100,000 seconds or more, and even more preferably 1,000,000 seconds or more.

[0045] The resin film may contain only the gas barrier resin (i.e., it may consist solely of the gas barrier resin), or it may contain other components that do not fall under any of the gas barrier resins (i.e., it may consist of the gas barrier resin and the other components).

[0046] <Other ingredients> The other components contained in the resin film are not particularly limited and can be arbitrarily selected depending on the purpose.

[0047] Examples of the other components mentioned above include additives known in the field. Examples of the aforementioned additives include antifogging agents, antiblocking agents, antioxidants, antistatic agents, nucleating agents, inorganic particles, organic particles, inorganic fibers, organic fibers, viscosity reducers, viscosity increasers, heat stabilizers, lubricants, infrared absorbers, and ultraviolet absorbers. Antifogging agents are preferably used because they can improve moisture permeability by making the resin film surface more water-friendly. Examples of antifogging agents include glycerin laurate, diglycerin laurate, decaglycerin laurate, glycerin monostearate, and sorbitan stearate. Inorganic and organic fibers can improve the film's film strength and water resistance. Examples of organic fibers include cellulose, with cellulose nanofiber (CNF) being preferably used.

[0048] The other components contained in the resin film may consist of only one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0049] ◎Second Implementation Next, the properties of the resin film of the second embodiment will be described. The resin film of the second embodiment according to the present invention has a water vapor permeability of 5000 g / m², as measured by the cup method specified in JIS Z 0208 under conditions of 30°C and 75% RH. 2The water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 45%RH, is 1500 g / m². 2 The air permeability resistance of the resin film is 5000 seconds or more, measured by the Wang Ren method specified in JIS P 8117:2009, under conditions of 23°C and 50%RH. The resin film of this embodiment has a water vapor permeability of 5000 g / m², as measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 75% RH. 2 The water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 45%RH, is 1500 g / m². 2 The resistance to air permeability of the resin film is 5000 seconds or more, as measured by the Wang Research method specified in JIS P 8117:2009 under conditions of 23°C and 50%RH. Therefore, it is possible to impart gas barrier properties to the substrate layer while suppressing a decrease in the moisture permeability of the substrate layer. Furthermore, it exhibits high moisture permeability in both high-humidity and low-humidity environments, and maintains high moisture permeability regardless of the external humidity environment.

[0050] The resin film of this embodiment, when laminated onto a highly permeable substrate layer, can suppress the decrease in the moisture permeability of the substrate layer while providing gas barrier properties to the substrate layer, even in high-humidity or low-humidity environments. Therefore, even if the contents are packaged without being completely dried, the contents can be dried after packaging. Furthermore, because the resin film of this embodiment can provide gas barrier properties to the substrate layer, deterioration of the contents can be prevented by sealing in an inert gas after packaging. For example, metal articles such as medical devices, industrial materials, and electronic components can be packaged without drying and then dried after packaging by sealing in an inert gas. This allows for quick packaging and prevents deterioration due to rust, etc.

[0051] The water vapor transmission rate of the resin film of this embodiment, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 75% RH, was 5000 g / m². 2 • day, 5500g / m² 2 It is preferable that it be 5600g / m² or more. 2 It is more preferable that it be 5700g / m² or more. 2 It is even more preferable that it be 5800g / m² or more. 2 ·day or more, 5900g / m 2 • 6000g / m² or more per day 2 ·day or more, 7000g / m 2 ·day or more, 8000g / m 2 ·day or more, 9000g / m 2 ·day or more, 10000g / m 2 • More than 1 day, and 12,000 g / m² 2 The duration may be any of the above-mentioned days or longer. The water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 75%RH, is equal to or greater than the above lower limit, thereby providing high moisture permeability even in high humidity environments.

[0052] The water vapor transmission rate of the resin film of this embodiment, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 45% RH, was 1500 g / m². 2 • More than 2000g / m² 2 It is preferable that it be 2500g / m² or more. 2 It is more preferable that it be 3000g / m² or more. 2 It is even more preferable that it be 3500g / m² or more. 2 ·day or more, 4000g / m 2 • More than 5000g / m² 2 The duration may be any of the above-mentioned days or longer. The water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208, under conditions of 30°C and 45%RH, is equal to or greater than the above lower limit, thereby providing high moisture permeability even in low humidity environments.

[0053] The amount of water vapor transmitted under the above conditions of 30°C and 75%RH, and the amount of water vapor transmitted under the above conditions of 30°C and 45%RH, can be adjusted, for example, by the type or content of the gas barrier resin, or by the thickness of the resin film.

[0054] The air permeability resistance of the resin film of this embodiment, measured by the Wangyan method specified in JIS P 8117:2009, under conditions of 23°C and 50%RH, is 5,000 seconds or more, preferably 100,000 seconds or more, more preferably 1,000,000 seconds or more, and may be any of 2,000,000 seconds or more, 3,000,000 seconds or more, 4,000,000 seconds or more, 5,000,000 seconds or more, 8,000,000 seconds or more, and 10,000,000 seconds or more. The above air permeability resistance being above the lower limit provides excellent gas barrier properties. The above air permeability resistance can be adjusted, for example, by the type or content of the gas barrier resin contained in the resin film, or by the thickness of the resin film.

[0055] The resin film of the second embodiment preferably has the same structure as the resin film of the first embodiment described above, in addition to the water vapor permeability at 30°C and 75%RH, the water vapor permeability at 30°C and 45%RH, and the air permeability resistance at 23°C and 50%RH. For example, the resin film of the second embodiment preferably contains either or both of polyvinyl alcohol and modified polyvinyl alcohol, and aqueous polyurethane as the gas barrier resin. In the resin film of the second embodiment, the ratio of [total content of polyvinyl alcohol and modified polyvinyl alcohol (parts by mass)] to [content of aqueous polyurethane (parts by mass)] is preferably 1:1 to 1:9.9. In the resin film of the second embodiment, it is preferable that one or more selected from the group consisting of polyvinyl alcohol, the modified polyvinyl alcohol, and the aqueous polyurethane have a crosslinked structure. The resin film of the second embodiment may contain a gas barrier resin, similar to the resin film of the first embodiment.

[0056] The resin films of the first and second embodiments of the present invention may consist of one layer (single layer) or of two or more layers. When the resin film consists of multiple layers, these layers may be the same or different from each other, and the combination of these layers is not particularly limited as long as it does not impair the effects of the present invention.

[0057] The thickness of the resin film in the first and second embodiments of the present invention is not particularly limited, but is preferably 0.1 μm or more and 5.0 μm or less, more preferably 0.3 μm or more and 4.0 μm or less, and may be any of 0.4 μm or more and 3.0 μm or less, or 0.4 μm or more and 2.0 μm or less. When the thickness of the resin film is above the lower limit, the effect of imparting gas barrier properties to the substrate layer is improved. When the thickness of the resin film is below the upper limit, the decrease in moisture permeability of the substrate layer can be further suppressed.

[0058] <Method for manufacturing resin film> The resin film of this embodiment can be formed on a substrate layer by, for example, coating a resin composition containing the gas barrier resin and, if necessary, the other components, onto one side of the substrate layer described later, and drying it as necessary. In this case, the structure of the target laminated film itself or a part thereof can be obtained immediately.

[0059] The aforementioned resin composition may contain a solvent, as this improves its coating properties. Examples of the aforementioned solvents include water, 2-propanol (IPA), ethanol, methanol, methyl ethyl ketone (MEK), ethyl acetate, toluene, and acetone.

[0060] The solvent contained in the resin composition may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0061] The method of producing the aforementioned resin film by coating it with a resin composition is particularly effective when the target resin film contains components that decompose, ignite, or vaporize at relatively low temperatures. Examples of such components that are not suitable for handling at high temperatures include potassium sorbate and sodium lactate.

[0062] The resin composition can be coated using any known method. For example, the resin composition can be coated using various coaters.

[0063] The drying conditions for the resin composition are not particularly limited, but if the resin composition contains a solvent as described later, it is preferable to heat dry it, and in this case, it is preferable to dry it at, for example, 40 to 120°C.

[0064] <<Laminated Film>> The structure of a laminated film, which is one embodiment to which the present invention is applied, will now be described. Figure 1 is a schematic cross-sectional view of a laminated film 1, which is one embodiment to which the present invention is applied. As shown in Figure 1, the laminated film 1 of this embodiment is generally composed of a resin film 2 of the present invention and a base layer 3 provided on the resin film 2. The laminated film 1 of this embodiment can be used as a packaging film for packaging, particularly for metal articles such as medical devices, industrial components, and electronic components.

[0065] <Base material layer> The base layer (also called the core layer) 3 is a resin layer provided on the resin film 2 described above. The base layer 3 can impart flexibility to the multilayer film 1. The resin that can be used for the base layer 3 is not particularly limited as long as it is a resin that can impart the above functions and is permeable to moisture, but examples include polyolefin resins, polyester resins, nylon resins, ethylene vinyl acetate copolymers, olefin elastomers, etc. The base layer may be porous or not, as long as it is permeable to moisture.

[0066] Examples of polyolefin resins include polyethylene copolymers, polypropylene copolymers, and butene copolymers, with polyethylene copolymers and polypropylene copolymers being preferred among these. Furthermore, from the viewpoint of improving adhesion, random copolymers, graft copolymers, block copolymers, and graft copolymers can be used as the form of these copolymers, with random copolymers being particularly preferred.

[0067] The aforementioned polyolefin resin is a copolymer of olefins. The aforementioned polyethylene copolymer is a copolymer of ethylene and a monomer other than ethylene. The aforementioned polypropylene copolymer is a copolymer of propylene and a monomer other than propylene. The aforementioned butene copolymer is a copolymer of butene and a monomer other than butene.

[0068] Polyethylene copolymers are not particularly limited, but examples include copolymers of ethylene and vinyl group-containing monomers.

[0069] Copolymers of ethylene and vinyl group-containing monomers include maleic anhydride graft-modified linear low-density polyethylene (hereinafter referred to as "LLDPE-g-MAH"), ethylene-vinyl acetate copolymer (hereinafter referred to as "EVA resin"), ethylene-methyl methacrylate copolymer (hereinafter referred to as "EMMA resin"), ethylene-ethyl acrylate copolymer (hereinafter referred to as "EEA resin"), ethylene-methyl acrylate copolymer (hereinafter referred to as "EMA resin"), ethylene-ethyl acrylate-maleic anhydride copolymer (hereinafter referred to as "E-EA-MAH resin"), ethylene-acrylic acid copolymer (hereinafter referred to as "EAA resin"), ethylene-methacrylic acid copolymer (hereinafter referred to as "EMAA resin"), ionomers (hereinafter referred to as "ION resin"), and ethylene-based thermoplastic elastomers. In this specification, ION resin refers to a copolymer of ethylene and a small amount of acrylic acid or methacrylic acid, which has been modified to form an ionic crosslinking structure by salt formation between the acid portion and metal ions.

[0070] Examples of polyester resins include polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, and polyhexamethylene terephthalate.

[0071] Examples of nylon resins include 4-nylon, 6-nylon, 7-nylon, 11-nylon, 12-nylon, 46-nylon, 66-nylon, 69-nylon, 610-nylon, 611-nylon, 612-nylon, 6T-nylon, 6I-nylon, copolymer of 6-nylon and 66-nylon (nylon 6 / 66), copolymer of 6-nylon and 610-nylon, copolymer of 6-nylon and 611-nylon, copolymer of 6-nylon and 12-nylon (nylon 6 / 12), copolymer of 6-nylon and 612-nylon, and 6-nylon. Examples include copolymers of nylon and 6T-nylon, copolymers of 6-nylon and 6I-nylon, copolymers of 6-nylon, 66-nylon and 610-nylon, copolymers of 6-nylon, 66-nylon and 12-nylon (nylon 6 / 66 / 12), copolymers of 6-nylon, 66-nylon and 612-nylon, copolymers of 66-nylon and 6T-nylon, copolymers of 66-nylon and 6I-nylon, copolymers of 6T-nylon and 6I-nylon, copolymers of 66-nylon, 6T-nylon and 6I-nylon, copolymers of 66-nylon, 6T-nylon and 6I-nylon, amorphous nylon, etc. Among these, nylon 6, nylon 12-nylon, nylon 6, nylon 6 / 66, nylon 6 / 12, and nylon 6 / 66 / 12 are preferred in terms of heat resistance, mechanical strength, and availability, with nylon 6 being more preferred.

[0072] The base layer 3 may consist of only one layer or of two or more layers. For example, by making the base layer 3 composed of multiple layers of different materials, the properties of the base layer 3, such as hardness and moisture permeability, can be adjusted.

[0073] The ratio of the thickness of the base layer 3 to the total thickness of the laminated film 1 is preferably 75 to 99.9%, more preferably 90 to 99.9%, even more preferably 95 to 99.9%, and particularly preferably 97 to 99.5%. If the above thickness ratio is above the lower limit, flexibility can be imparted to the multilayer film 1. If the above thickness ratio is below the upper limit, the decrease in moisture permeability when the resin film is laminated is suppressed.

[0074] The thickness of the base layer 3 is preferably 10 to 100 μm, and more preferably 15 to 50 μm. If the above thickness is above the lower limit of the preferred range, the decrease in moisture permeability when the resin film is laminated is suppressed, and if it is below the upper limit, flexibility is obtained.

[0075] <Method for manufacturing laminated film> Next, the manufacturing method for the laminated film 1 described above will be explained. The method for manufacturing the laminated film 1 of this embodiment is not particularly limited, but for example, it can be manufactured by coating the resin composition for forming the resin film onto one surface of a substrate layer, drying it as necessary, and then laminating the resin film onto one surface of the substrate layer.

[0076] <<Packaging and Method for Manufacturing the Same>> A package can be manufactured by using the laminated film, placing the resin film within it on the side of the object to be packaged, and then packaging the object. Because the packaging body includes the resin film, the contents inside the packaging body can be dried after packaging, and deterioration of the contents can be prevented by sealing an inert gas inside the packaging body. Therefore, deterioration due to rust, etc., of metal articles such as medical devices, industrial materials, and electronic components can be prevented.

[0077] During packaging, for example, the object to be packaged can be wrapped in a single laminated film, and the excess portion of the laminated film (the portion not wrapping the object) can be overlapped with other portions of the laminated film and sealed to package the object. At this time, the resin films within the laminated film may be overlapped with each other, or the resin film may be overlapped with the base layer. Furthermore, during packaging, for example, the object to be packaged can be sandwiched between two of the laminated films, and these laminated films can be overlapped and sealed to package the object. In this case, the resin films within the laminated film may be overlapped with each other, or the resin film may be overlapped with the base layer. Furthermore, by using a tray, placing the object to be packaged on it, and sealing the resin film in the laminated film to the periphery of the tray, the object to be packaged can be wrapped. [Examples]

[0078] The effects of the present invention will be described in detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[0079] [Example 1] <<Manufacturing of resin films and laminated films>> A resin solution was obtained by mixing modified polyvinyl alcohol (Mitsubishi Chemical's "Gosenex WO320N") (solid, viscosity of 4% by mass aqueous solution at 20°C: 6.5-8.5 mPa·s, degree of saponification: 97.5-99 mol%) diluted to 3% by mass with a solvent (water), aqueous polyurethane (DIC's "Hydran WLS-230") (solid content: 35% by mass) diluted to 3% by mass with a solvent (water), and titanium-based crosslinking agent (Matsumoto Fine Chemical's "Orgatics TC400") 60 phr (60 parts by mass of Orgatics TC400 per 100 parts by mass of modified polyvinyl alcohol). This solution was applied to one side of a base film (3M's "Microporous Film", thickness 30 μm) and dried at 100°C for 2 minutes to form a resin film (thickness 1 μm) on the base film. The resin solution corresponds to the resin composition for forming the resin film, and the base film corresponds to the base layer described above. As a result, a laminated film was obtained in which a resin film was laminated onto a base film.

[0080] [Example 2] <<Manufacturing of resin films and laminated films>> Instead of using modified polyvinyl alcohol (Mitsubishi Chemical's "Gosenex WO320N") (solid, 4% by mass aqueous solution viscosity at 20°C: 6.5-8.5 mPa·s, degree of saponification: 97.5-99 mol%) diluted with a solvent (water) to a solid content concentration of 3% by mass, and aqueous polyurethane (DIC's "Hydran WLS-230") (solid content concentration: 35% by mass) diluted with a solvent (water) to a solid content concentration of 3% by mass, modified polyvinyl alcohol (Mitsubishi Chemical's "Gosenex WO320N") (solid A resin film (1 μm thick) was formed on a substrate film in the same manner as in Example 1, except that a 4% aqueous solution with a solid content of 2% by mass, viscosity at 20°C: 6.5-8.5 mPa·s, degree of saponification: 97.5-99 mol%) was diluted to a solid content of 3% by mass with a solvent (water:2-propanol = 8:2 mixed solvent), and an aqueous polyurethane (DIC Corporation's "Hydran WLS-230") (solid content: 35% by mass) was diluted to a solid content of 3% by mass with a solvent (water:2-propanol = 8:2 mixed solvent). As a result, a laminated film was obtained in which a resin film was laminated onto a base film.

[0081] [Example 3] <<Manufacturing of resin films and laminated films>> Instead of using modified polyvinyl alcohol (Mitsubishi Chemical's "Gosenex WO320N") (solid, 4% by mass aqueous solution viscosity at 20°C: 6.5-8.5 mPa·s, degree of saponification: 97.5-99 mol%) diluted with a solvent (water) to a solid content concentration of 3% by mass, and aqueous polyurethane (DIC's "Hydran WLS-230") (solid content concentration: 35% by mass) diluted with a solvent (water) to a solid content concentration of 3% by mass, modified polyvinyl alcohol (Mitsubishi Chemical's "Gosenex WO320N") A resin film (1 μm thick) was formed on a substrate film in the same manner as in Example 1, except that a 4% by mass aqueous solution of ) (solid, viscosity at 20°C: 6.5~8.5 mPa·s, degree of saponification: 97.5-99 mol%) was diluted to a solid content concentration of 3% by mass with a solvent (water:2-propanol = 8:2 mixed solvent), and an aqueous polyurethane (DIC Corporation's "Hydran WLS-230") (solid content concentration: 35% by mass) was diluted to a solid content concentration of 3% by mass with a solvent (water:2-propanol = 8:2 mixed solvent). As a result, a laminated film was obtained in which a resin film was laminated onto a base film.

[0082] [Example 4] <<Manufacturing of resin films and laminated films>> Instead of using modified polyvinyl alcohol (Mitsubishi Chemical's "Gosenex WO320N") (solid, 4% by mass aqueous solution viscosity at 20°C: 6.5-8.5 mPa·s, degree of saponification: 97.5-99 mol%) diluted with a solvent (water) to a solid content concentration of 3% by mass, and aqueous polyurethane (DIC's "Hydran WLS-230") (solid content concentration: 35% by mass) diluted with a solvent (water) to a solid content concentration of 3% by mass, modified polyvinyl alcohol (Mitsubishi Chemical's "Gosenex WO320N") A resin film (1 μm thick) was formed on a substrate film in the same manner as in Example 1, except that a 4% by mass aqueous solution of ) (solid, viscosity at 20°C: 6.5~8.5 mPa·s, degree of saponification: 97.5-99 mol%) was diluted to a solid content concentration of 3% by mass with a solvent (water:2-propanol = 8:2 mixed solvent), and an aqueous polyurethane (DIC Corporation's "Hydran WLS-230") (solid content concentration: 35% by mass) was diluted to a solid content concentration of 3% by mass with a solvent (water:2-propanol = 8:2 mixed solvent). As a result, a laminated film was obtained in which a resin film was laminated onto a base film.

[0083] [Example 5] <<Manufacturing of resin films and laminated films>> Instead of using modified polyvinyl alcohol (Mitsubishi Chemical's "Gosenex WO320N") (solid, 4% by mass aqueous solution viscosity at 20°C: 6.5-8.5 mPa·s, degree of saponification: 97.5-99 mol%) diluted with solvent (water) to a solid content concentration of 3% by mass, and aqueous polyurethane (DIC's "Hydran WLS-230") (solid content concentration: 35% by mass) diluted with solvent (water) to a solid content concentration of 3% by mass, modified polyvinyl alcohol (Kuraray's "Exceval RS-2117") (solid content A resin film (1 μm thick) was formed on a substrate film in the same manner as in Example 1, except that a 4% aqueous solution with a concentration of 100% by mass, viscosity at 20°C: 26.5 mPa·s, degree of saponification: 97.5-99 mol%) was diluted to a solid content concentration of 3% by mass with a solvent (water:2-propanol = 8:2 mixed solvent), and an aqueous polyurethane (DIC Corporation's "Hydran WLS-230") (solid content concentration: 35% by mass) was diluted to a solid content concentration of 3% by mass with a solvent (water:2-propanol = 8:2 mixed solvent). As a result, a laminated film was obtained in which a resin film was laminated onto a base film.

[0084] [Example 6] <<Manufacturing of resin films and laminated films>> Instead of using modified polyvinyl alcohol (Mitsubishi Chemical's "Gosenex WO320N") (solid, 4% by mass aqueous solution viscosity at 20°C: 6.5-8.5 mPa·s, degree of saponification: 97.5-99 mol%) diluted with a solvent (water) to a solid content concentration of 3% by mass, and aqueous polyurethane (DIC's "Hydran WLS-230") (solid content concentration: 35% by mass) diluted with a solvent (water) to a solid content concentration of 3% by mass, modified polyvinyl alcohol (Daiichi Kogyo Seiyaku Co., Ltd. "Pitzcol V-715") A resin film (1 μm thick) was formed on a substrate film in the same manner as in Example 1, except that a solution of 4) (solid content concentration: 15% by mass aqueous solution, viscosity of 4% by mass aqueous solution at 20°C: 10-20 mPa·s) was diluted to a solid content concentration of 3% by mass with a solvent (water:2-propanol = 8:2 mixed solvent), and an aqueous polyurethane (DIC Corporation's "Hydran WLS-230") (solid content concentration: 35% by mass) was diluted to a solid content concentration of 3% by mass with a solvent (water:2-propanol = 8:2 mixed solvent). As a result, a laminated film was obtained in which a resin film was laminated onto a base film.

[0085] [Comparative Example 1] <<Manufacturing of resin films and laminated films>> A resin solution was obtained by mixing a modified polyvinyl alcohol (Mitsubishi Chemical's "Gosenex WO320N") (solid, viscosity of 4% by mass aqueous solution at 20°C: 6.5-8.5 mPa·s, degree of saponification: 97.5-99 mol%) diluted to a solid content concentration of 3% by mass with a solvent (water), and 60 phr of a titanium-based crosslinking agent (Matsumoto Fine Chemical's "Orgatics TC400") (60 parts by mass of Orgatics TC400 per 100 parts by mass of modified polyvinyl alcohol). This solution was coated onto one side of a base film (3M's "Microporous Film", 30 μm thick) and dried at 100°C for 2 minutes to form a resin film (1 μm thick) on the base film. As a result, a laminated film was obtained in which a resin film was laminated onto a base film.

[0086] [Comparative Example 2] <<Manufacturing of resin films and laminated films>> A resin solution was prepared by diluting an aqueous polyurethane (DIC Corporation's "Hydran WLS-230") (solid content concentration: 35% by mass) with a solvent (water:2-propanol = 8:2 mixed solvent) to a solid content concentration of 3% by mass. This resin solution was coated onto one side of a base film (3M Corporation's "Microporous Film", thickness 30 μm) and dried at 100°C for 2 minutes to form a resin film (thickness 1 μm) on the base film. As a result, a laminated film was obtained in which a resin film was laminated onto a base film.

[0087] [Comparative Example 3] <<Manufacturing of resin films and laminated films>> A resin film (1 μm thick) was formed on a substrate film in the same manner as in Comparative Example 1, except that instead of using modified polyvinyl alcohol ("Gosenex WO320N" manufactured by Mitsubishi Chemical Corporation) (solid, viscosity of 4% by mass aqueous solution at 20°C: 6.5-8.5 mPa·s, degree of saponification: 97.5-99 mol%) diluted to a solid content concentration of 3% by mass with a solvent (water), modified polyvinyl alcohol ("Pitzcol V-7154" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (solid content concentration: 15% by mass aqueous solution, viscosity of 4% by mass aqueous solution at 20°C: 10-20 mPa·s) was used. As a result, a laminated film was obtained in which a resin film was laminated onto a base film.

[0088] <<Measurement of water vapor permeability of resin film>> The laminated films obtained in Examples 1-6 and Comparative Examples 1-3, and the base films used in the above examples and comparative examples (3M's "Microporous Film," 30 μm thick), were measured for water vapor transmission under conditions of 30°C, 75% RH and 30°C, 45% RH using the cup method specified in JIS Z 0208. The measurements were performed by placing 10 g of dry calcium chloride in a container with a diameter of 60 mm. Next, for the laminated films of Examples 1-6 and Comparative Examples 1-3, the water vapor transmission rate of the resin film without the base film was calculated from the measured water vapor transmission rate of the laminated film using the following formula. The results are shown in Table 1.

[0089]

number

[0090] <<Measurement of air permeability resistance of resin film>> The air permeability resistance of the laminated films obtained in Examples 1-6 and Comparative Examples 1-3, and the base film used in the above examples and comparative examples (3M's "Microporous Film," 30 μm thick), was measured at 23°C and 50% humidity using the Wang-Jian method specified in JIS P 8117:2009. Next, for the laminated films in Examples 1-6 and Comparative Examples 1-3, the air permeability resistance of the resin film in each example was calculated by subtracting the air permeability resistance of the laminated film in each example from the air permeability resistance of the base film. The results are shown in Table 1.

[0091] <<Evaluation of the formation state of the resin film in laminated films>> The surface of the resin film (the exposed surface opposite to the base film side) of the laminated films obtained in Examples 1 to 6 and Comparative Examples 1 to 3 was visually observed, and the formation state of the resin film in the laminated films was evaluated according to the following evaluation criteria. <Evaluation Criteria> A: The resin film is uniformly formed on the base film. B: The resin film is not uniformly formed on the base film, and there are areas on the base film where no resin film is formed.

[0092] [Table 1]

[0093] As is clear from the results above, the resin films of Examples 1 to 6 had a water vapor transmission rate of 5000 g / m² under conditions of 30°C and 75% RH. 2 • For periods of 24 hours or more, and under conditions of 30°C and 45%RH, the water vapor transmission rate is 1500 g / m³. 2 The film exhibited excellent moisture permeability in both high and low humidity environments, with a water vapor transmission rate of 5000 g / m² or more. Furthermore, it had excellent gas barrier properties, as its air permeability resistance was 5000 seconds or more, and its formation state was also excellent. In contrast, the resin films of Comparative Examples 1 and 3 had a water vapor transmission rate of 1500 g / m² under conditions of 30°C and 45% RH. 2 The water vapor permeability was less than 5000 g / m² under low humidity conditions. The resin film of Comparative Example 3 had a water vapor transmission rate of 5000 g / m² under conditions of 30°C and 75% RH. 2 The first comparative example had a resistance to air permeability of less than 5000 seconds and was inferior in terms of moisture permeability under high humidity conditions. Furthermore, the resin film of comparative example 2 had an air permeability resistance of less than 5000 seconds and was inferior in terms of gas barrier properties. In addition, the resin film of comparative example 2 was also inferior in terms of its formation state. [Industrial applicability]

[0094] This invention can be used for packaging metal articles such as medical devices, industrial components, and electronic components. [Explanation of symbols]

[0095] 1…Laminated film 2… Resin film 3...Base material layer

Claims

1. It is a resin film, The aforementioned resin film comprises either or both of polyvinyl alcohol and modified polyvinyl alcohol, and aqueous polyurethane. In the aforementioned resin film, the ratio of [total content of polyvinyl alcohol and modified polyvinyl alcohol (parts by mass)] to [content of aqueous polyurethane (parts by mass)] is 1:1 to 1:9.

9. One or more selected from the group consisting of the aforementioned polyvinyl alcohol, the modified polyvinyl alcohol, and the aqueous polyurethane have a crosslinked structure. A resin film containing a titanium compound in the aforementioned cross-linked structure.

2. The water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208 under conditions of 30°C and 75% RH, was 5000 g / m². ２ - It is more than one day, The water vapor permeability of the resin film, measured by the cup method specified in JIS Z 0208 under conditions of 30°C and 45% RH, was 1500 g / m². ２ The resin film according to claim 1, wherein the film is of day or longer.

3. The resin film according to claim 1, wherein the air permeability resistance of the resin film, measured by the Wangyan method specified in JIS P 8117:2009, under conditions of 23°C and 50% RH, is 5000 seconds or more.

4. The resin film according to claim 1, wherein the thickness of the resin film is 0.1 μm or more and 5.0 μm or less.

5. A laminated film comprising a resin film according to claim 1 and a substrate layer provided on the resin film.

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