Resin film and laminate film

Abstract

To provide a resin film and a laminate film having excellent water vapor permeability even in low-humidity environments and excellent gas barrier properties.SOLUTION: There is provided a resin film 2 in which a water-based polyurethane and a cross-linking agent are blended, the cross-linking agent comprises one or two or more selected from the group consisting of a titanium compound and a metal chelating compound and there is provided a laminate film 1 comprising the resin film 2 in which the blending amount of the cross-linking agent is 35 pts.mass or more based on 100 pts.mass of the blending amount of the water-based polyurethane and a base material layer 3 provided on the resin film 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a resin film and a laminate film. [Background technology]

[0002] When packaging metallic contents such as medical devices, industrial materials, and electronic components, it is necessary to dry the contents before packaging in order to prevent rust, etc. If the contents are not completely dry, they must be dried after packaging, but to do so, the film used to package the contents must be moisture permeable.

[0003] Although highly moisture-permeable base films have been known (for example, Patent Document 1), the conventional highly moisture-permeable base films cannot ensure gas barrier properties, and therefore the contents may deteriorate due to oxidation. In addition, in order to prevent deterioration of the contents, it is necessary to seal in an inert gas such as carbon dioxide or nitrogen, but the conventional highly moisture-permeable base films also permeate the inert gas, making it impossible to seal in the inert gas, and therefore making it difficult to prevent deterioration of the packaged contents. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-163357 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a resin film that can be laminated to a highly moisture-permeable substrate layer to impart gas barrier properties to the substrate layer while suppressing a decrease in the moisture permeability of the substrate layer.

[0006] In addition, a resin film containing polyvinyl alcohol has a problem that it has high moisture permeability in a high humidity environment, but its moisture permeability decreases in a low humidity environment. In addition, if the resin composition contained in the resin film cannot be applied uniformly to the surface of the base layer, the resin film cannot be formed uniformly on the base layer, which leads to a decrease in the gas barrier property of the resin film on the base layer, in-plane variation in moisture permeability, and poor appearance. Therefore, an object of the present invention is to provide a resin film that has high moisture permeability even in a low humidity environment, has high moisture permeability regardless of the external humidity environment, and can be formed uniformly on a substrate layer.

[0007] A further object of the present invention is to provide a laminated film having excellent moisture permeability and excellent gas barrier properties. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention employs the following configuration.

[0009] [1] A resin film, The resin film contains an aqueous polyurethane and a crosslinking agent, the crosslinking agent is one or more selected from the group consisting of titanium compounds and metal chelate compounds, The resin film, wherein the blending amount of the crosslinking agent is 35 parts by mass or more per 100 parts by mass of the aqueous polyurethane. [2] The water vapor transmission rate of the resin film measured by the cup method specified in JIS Z 0208 at 30°C and 75% RH is 5,500 g / m 2 ·day or more, The water vapor transmission rate of the resin film measured by the cup method specified in JIS Z 0208 at 30°C and 45% RH is 3000g / m 2 ·day or more, The resin film according to [1], wherein the air permeability resistance of the resin film is 5000 seconds or more at 23°C and 50% RH, as measured by the Oken method specified in JIS P 8117:2009. [3] The resin film according to [1] or [2], wherein the thickness of the resin film is 0.1 μm or more and 4.0 μm or less. [4] A laminate film comprising the resin film according to [1] or [2] and a base layer provided on the resin film. Effect of the Invention

[0010] The resin film of the present invention contains an aqueous polyurethane and a crosslinking agent, the crosslinking agent being one or more selected from the group consisting of titanium compounds and metal chelate compounds, and the amount of the crosslinking agent in the resin film is 35 parts by mass or more per 100 parts by mass of the aqueous polyurethane, so that the base layer can be given gas barrier properties while suppressing a decrease in the moisture permeability of the base layer. In addition, the resin film of the present invention has high moisture permeability both in high humidity environments and low humidity environments, has high moisture permeability regardless of the external humidity environment, and can be formed uniformly on the base layer.

[0011] Furthermore, since the laminate film of the present invention comprises the resin film and a base layer provided on the resin film, it has excellent moisture permeability and gas barrier properties, and also has high moisture permeability both in high humidity environments and low humidity environments, and has high moisture permeability regardless of the external humidity environment. [Brief description of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing a configuration of a laminated film provided with a resin film, which is one embodiment to which the present invention is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a resin film according to an embodiment of the present invention and a laminate film including the resin film will be described in detail. Note that the drawings used in the following description may show characteristic parts in an enlarged scale for the sake of convenience in order to make the characteristics easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

[0014] <<Resin film>> The resin film of this embodiment is formulated with an aqueous polyurethane and a crosslinking agent, the crosslinking agent consisting of one or more compounds selected from the group consisting of titanium compounds and metal chelate compounds, and the amount of the crosslinking agent in the resin film is 35 parts by mass or more per 100 parts by mass of the aqueous polyurethane. The resin film of this embodiment contains an aqueous polyurethane and a crosslinking agent, the crosslinking agent being one or more selected from the group consisting of titanium compounds and metal chelate compounds, and the amount of the crosslinking agent in the resin film is 35 parts by mass or more per 100 parts by mass of the aqueous polyurethane, so that the base layer can be given gas barrier properties while suppressing a decrease in the moisture permeability of the base layer. In addition, the resin film of this embodiment has high moisture permeability both in high humidity environments and low humidity environments, has high moisture permeability regardless of the external humidity environment, and can be formed uniformly on the base layer.

[0015] The resin film of this embodiment can be laminated on a highly moisture-permeable substrate layer, and can impart gas barrier properties to the substrate layer while suppressing the decrease in moisture permeability of the substrate layer even in a high humidity environment or a low humidity environment. Therefore, even if the contents are packaged without being completely dried, the contents can be dried after packaging. In addition, since the resin film of this embodiment can impart gas barrier properties to the substrate layer, deterioration of the contents can be prevented by sealing in an inert gas after packaging. Therefore, for example, metal articles such as medical devices, industrial materials, and electronic components can be packaged without drying, and by sealing in an inert gas after packaging, they can be dried after packaging, so that packaging can be performed in a short time and deterioration due to rust generation can be prevented. Furthermore, the resin film of this embodiment can be uniformly formed on the substrate layer because the resin composition containing the aqueous polyurethane can be uniformly applied to the surface of the substrate layer. Therefore, there is no decrease in the gas barrier properties of the resin film on the substrate layer, no in-plane variation in moisture permeability, and the appearance is also excellent. In this specification, a "low humidity environment" refers to, for example, an environment with a relative humidity of 45% or less, a "high humidity environment" refers to, for example, an environment with a relative humidity of 75% or more, and a "medium humidity environment" refers to, for example, an environment with a relative humidity of more than 45% and less than 75%.

[0016] <Gas barrier resin> The resin film of the present embodiment contains a gas barrier resin. The gas barrier resin is a resin that suppresses the permeation of gas and imparts gas barrier properties to the base layer. The type of gas is not particularly limited as long as it does not affect the contents packaged in the laminated film described below, and examples of the gas include carbon dioxide and nitrogen.

[0017] The resin film of the present embodiment contains an aqueous polyurethane as a resin constituting the gas barrier resin. In this specification, the aqueous polyurethane refers to polyurethane microparticles having a particle size of 5 to 1000 nm, which is a water-dispersed polyurethane. Polyurethane is usually insoluble in water, but aqueous polyurethane can be dispersed in water. The particle size of the polyurethane microparticles is determined by a laser diffraction method. Examples of polyurethanes include polyester-based, polycarbonate-based, and polyether-based polyurethanes. In this specification, "polyester-based polyurethane" means "polyurethane having a polyester segment". "Polycarbonate-based polyurethane" means "polyurethane having a polycarbonate segment". "Polyether-based polyurethane" means "polyurethane having a polyether segment". In terms of the effect of increasing moisture permeability, polyether polyurethanes having highly hydrophilic polyether segments in the molecular chain are preferred. Specifically, those having polyether segments such as polyoxyethylene glycol or block copolymers of polyoxyethylene and polyoxypropylene, and having a long length between urethane bonds, are preferred. In order to improve moisture permeability, the Tg of polyurethane is preferably 25°C or less, more preferably -20°C or less, and particularly preferably -50°C or less. In addition, as the aqueous polyurethane, a varnish in which the aqueous polyurethane is dispersed in water or a mixed solvent of water and an organic solvent may be used. It is preferable to use an aqueous dispersion type in terms of not damaging the environment and having the effect of suppressing penetration and erosion into the substrate. An example of a varnish in which an aqueous polyurethane is dispersed is Hydran (product name: manufactured by DIC Corporation).

[0018] The resin film may contain only one type of aqueous polyurethane, or two or more types. When two or more types are contained, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0019] In the resin film, the ratio of the content of the gas barrier resin to the total mass of the resin film (([content of aqueous polyurethane in resin film (parts by mass)] + [content of crosslinking agent in resin film (parts by mass)]) / [total mass of resin film (parts by mass)] × 100) is preferably 90% by mass or more, and may be, for example, any one of 95% by mass or more, 97% by mass or more, and 99% by mass or more. When the ratio is equal to or more than the lower limit, the effect of using the resin is more pronounced, and the gas barrier property of the resin film is further improved. There is no particular upper limit to the ratio, so long as the ratio is 100% by mass or less.

[0020] In the resin film, the content ratio of the gas barrier resin to the total mass of the resin film may be set to a different numerical range in addition to the above-mentioned numerical range depending on the application of the resin film.

[0021] In the resin film, the aqueous polyurethane has a crosslinked structure. For example, in the resin film, the aqueous polyurethanes are crosslinked to each other. The resin film may or may not further contain uncrosslinked aqueous polyurethane in addition to the crosslinked product of the aqueous polyurethane, which is the gas barrier resin.

[0022] The crosslinked structure can be formed by reacting a crosslinking agent with an aqueous polyurethane that does not have a crosslinked structure. The aqueous polyurethane has a crosslinked structure, which can improve the water resistance of the resin film. In addition, the substrate layer can be provided with gas barrier properties while suppressing a decrease in moisture permeability of the substrate layer.

[0023] (Crosslinking agent) The crosslinking agent either reacts with the water-based polyurethane to crosslink it, or does not react with the water-based polyurethane but crosslinks them by interacting with it.

[0024] The crosslinking agent is one or more selected from titanium compounds and metal chelate compounds. Examples of titanium compounds include titanium alkoxide compounds and titanium acylate compounds. Examples of metal chelate compounds include zirconium compounds (for example, "Zircosol AC-7" and "Zircosol ZC-20" manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.). Among them, titanium compounds are preferably used because they are polyfunctional and highly reactive with the hydroxyl groups of aqueous polyurethane, and further, varnishes are easily prepared at room temperature, and the varnish is applied to a substrate and sufficiently reacts with aqueous polyurethane at the temperature at which it is dried. That is, it is preferable that the resin film contains a titanium compound in the crosslinked structure. Here, the titanium compound contained in the crosslinked structure is the titanium compound itself, which is a crosslinking agent, or a compound (structure) derived from the titanium compound, which is a crosslinking agent. Specific examples of titanium compounds that are crosslinking agents include titanium lactate (eg, "Orgatix TC310" manufactured by Matsumoto Fine Chemical Co., Ltd.), titanium triethanol aminate (eg, "Orgatix TC400" manufactured by Matsumoto Fine Chemical Co., Ltd.), and the like.

[0025] The crosslinking agent to be reacted with the aqueous polyurethane may be one type only, or two or more types may be used. When two or more types are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0026] In the resin film, the blending amount of the crosslinking agent is 35 parts by mass or more, preferably 40 parts by mass or more, more preferably 50 parts by mass or more, particularly preferably 60 parts by mass or more, and may be 65 parts by mass or more, 70 parts by mass or more, 75 parts by mass or more, 80 parts by mass or more, 85 parts by mass or more, 90 parts by mass or more, or 95 parts by mass or more, relative to 100 parts by mass of the aqueous polyurethane blending amount (parts by mass). However, these are examples of the blending amounts. By the blending amount of the crosslinking agent being the above lower limit value or more relative to 100 parts by mass of the aqueous polyurethane blending amount (parts by mass), the resin film can be uniformly formed on the substrate layer, and the substrate layer can be provided with gas barrier properties. In addition, in the resin film, the blending amount of the crosslinking agent is preferably 130 parts by mass or less, more preferably 120 parts by mass or less, and particularly preferably 100 parts by mass or less, per 100 parts by mass of the aqueous polyurethane blending amount (parts by mass). However, these are just examples of the blending amounts. By blending the crosslinking agent at or below the upper limit value per 100 parts by mass of the aqueous polyurethane blending amount (parts by mass), it is possible to eliminate the remaining unreacted matter, and it is possible to suppress the deterioration of the gas barrier property caused by the unreacted matter dissolving in water.

[0027] The temperature (crosslinking temperature) when the crosslinking agent is allowed to react with the aqueous polyurethane is preferably 70 to 120°C, and more preferably 90 to 110°C. The time for which the crosslinking agent is allowed to act (crosslinking time) is preferably from 0.1 minute to 2 hours, more preferably from 0.2 minutes to 10 minutes, and even more preferably from 0.3 minutes to 3 minutes.

[0028] When the crosslinking agent is reacted with the aqueous polyurethane, it is preferable to use a solvent. Examples of the solvent include water, ethanol, 2-propanol, and ethyl acetate. The solvent may be one type only, or two or more types may be used. When two or more types are used, the combination and ratio thereof can be arbitrarily selected depending on 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.

[0029] The resin film is blended with an aqueous polyurethane and a crosslinking agent, and the crosslinking agent is one or more selected from the group consisting of titanium compounds and metal chelate compounds. In the resin film, the blending amount of the crosslinking agent is 35 parts by mass or more relative to 100 parts by mass of the blending amount of the polyether-based aqueous polyurethane, so that the resin film has high moisture permeability not only in a high humidity environment but also in a low humidity environment. In addition, since the resin composition containing the 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 a high humidity environment can be evaluated, for example, by the water vapor transmission amount measured by the cup method specified in JIS Z 0208 under conditions of 30°C and 75% RH. In addition, the moisture permeability of the resin film in a low humidity environment can be evaluated by the water vapor transmission amount measured by the cup method specified in JIS Z 0208 under conditions of 30°C and 45% RH.

[0030] The water vapor transmission rate of the resin film measured by the cup method specified in JIS Z 0208 at 30°C and 75% RH (relative humidity 75%) was 5500 g / m 2 ·day or more is preferable, and 5600g / m 2 5700g / m 2 5800g / m 2 5900g / m 2 ·day or more is most preferable, and 6000g / m 2 ·day or more, 6500g / m 2 ·day or more, 7000g / m 2 ·day or more, 7500g / m 2 ·day or more, 8000g / m 2 ·day or more, 8500g / m 2 ·day or more, 9000g / m 2 ·day or more, 9500g / m 2 ·day or more, 10000g / m 2 ·day or more, 11000g / m2 -day or more, and 12000g / m 2 When 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 75% RH is equal to or more than the above lower limit, the resin film has high moisture permeability even in a high humidity environment.

[0031] The water vapor transmission rate of the resin film measured by the cup method specified in JIS Z 0208 at 30°C and 45% RH (relative humidity 45%) is 3000 g / m 2 ·day or more is preferable, and 3500g / m 2 ·day or more is preferable, and 4000g / m 2 4500g / m 2 It is particularly preferable that the g / m 2 · day or more, 6000g / m 2 day or more, and 7000g / m 2 When 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 equal to or more than the above lower limit, the resin film has high moisture permeability even in a low humidity environment. On the other hand, 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 was 5000 g / m 2 When 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 equal to or less than the above upper limit, it is possible to achieve both moisture permeability and gas barrier property in a low humidity environment.

[0032] A preferable resin film of the present embodiment is, for example, a resin film having a water vapor transmission rate of preferably 5,500 g / m at 30° C. and 75% RH, measured by the cup method specified in JIS Z 0208. 2・day or more, preferably 5600g / m 2 ・day or more, more preferably 5700g / m 2 ・day or more, particularly preferably 5800g / m 2 day or more, most preferably 5900g / m 2 ·day or more, and the water vapor transmission rate of the resin film measured by the cup method specified in JIS Z 0208 at 30°C and 45% RH is preferably 3000 g / m 2 ·day or more, preferably 3500g / m 2 ·day or more, more preferably 4000g / m 2 ·day or more, and particularly preferably 4500 g / m 2 When 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 75% RH 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 are equal to or higher than the lower limit, the resin film has high moisture permeability both in high humidity environments and low humidity environments, and the resin film has high moisture permeability regardless of the external environment. On the other hand, 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 75% RH is 10000g / m 2 When 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 75% RH is equal to or less than the above upper limit, it is possible to achieve both moisture permeability and gas barrier property in a high humidity environment.

[0033] The water vapor permeation amount under the above conditions of 30°C and 75% RH and the water vapor permeation amount 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 the thickness of the resin film.

[0034] The air permeability resistance of the resin film measured by the Oken method specified in JIS P 8117:2009 under conditions of 23°C and 50% RH (relative humidity 50%) is preferably 5000 seconds or more, preferably 100,000 seconds or more, more preferably 1 million seconds or more, and may be any of 2 million seconds or more, 3 million seconds or more, 4 million seconds or more, 5 million seconds or more, 8 million seconds or more, and 10 million seconds or more. When the air permeability resistance is the lower limit or more, the gas barrier property is excellent. The air permeability resistance of the air can be adjusted, for example, by the type or content of the gas barrier resin, or the thickness of the resin film. Meanwhile, the air permeability resistance of the resin film at 23°C and 50% RH, measured by the Oken method specified in JIS P 8117: 2009, may be 15 million seconds or less. When the air permeability resistance of the resin film at 23°C and 50% RH, measured by the Oken method specified in JIS P 8117: 2009, is equal to or less than the upper limit, it is possible to achieve both gas barrier properties and water vapor permeability, and to maintain high measurement accuracy of the device.

[0035] A more preferable resin film of the present embodiment is, for example, a resin film having a water vapor transmission rate of preferably 5,500 g / m at 30° C. and 75% RH, measured by the cup method specified in JIS Z 0208. 2 ・day or more, preferably 5600g / m 2 ・day or more, more preferably 5700g / m 2 ・day or more, particularly preferably 5800g / m 2 day or more, most preferably 5900g / m 2 ·day or more, and the water vapor transmission rate of the resin film measured by the cup method specified in JIS Z 0208 at 30°C and 45% RH is preferably 3000 g / m 2 ·day or more, preferably 3500g / m 2 ·day or more, more preferably 4000g / m 2 ·day or more, and particularly preferably 4500 g / m 2100 days or more, and the air permeability resistance of the resin film at 23°C and 50% RH, measured by the Oken method specified in JIS P 8117:2009, is preferably 5,000 seconds or more, more preferably 100,000 seconds or more, and even more preferably 1,000,000 seconds or more.

[0036] The resin film may contain only the gas barrier resin (i.e., it may consist of the gas barrier resin), or it may contain other components that do not fall into any of the gas barrier resins (i.e., it may consist of the gas barrier resin and the other components).

[0037] <Other ingredients> The other components contained in the resin film are not particularly limited and can be arbitrarily selected depending on the purpose.

[0038] Examples of the other components include additives known in the art. Examples of the additives include antifogging agents, antiblocking agents, antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, inorganic fibers, organic fibers, viscosity reducers, thickeners, 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 compatible with water. Examples of antifogging agents include glycerin laurate, diglycerin laurate, decaglycerin laurate, glycerin monostearate, and sorbitan stearate. Inorganic and organic fibers can improve the film strength and water resistance of the film. Examples of organic fibers include cellulose, and cellulose nanofibers (CNF) are preferably used.

[0039] The resin film may contain only one type of other component, or two or more types. When there are two or more types, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0040] The resin film of the present embodiment may be one layer (single layer) or may be two or more layers. When the resin film is made of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited as long as it does not impair the effects of the present invention.

[0041] The thickness of the resin film of the present embodiment is not particularly limited, but is preferably 0.1 μm or more and 4.0 μm or less, more preferably 0.3 μm or more and 4.0 μm or less, and may be, for example, any of 0.3 μm or more and 3.0 μm or less, 0.3 μm or more and 2.0 μm or less, and 0.3 μm or more and 1.5 μm or less. When the thickness of the resin film is equal to or more than the lower limit, the effect of imparting gas barrier properties to the base layer is improved. When the thickness of the resin film is equal to or less than the upper limit, the decrease in moisture permeability of the base layer can be further suppressed.

[0042] <Method of manufacturing resin film> The resin film of the present embodiment can be formed on a substrate layer by, for example, applying a resin composition containing the gas barrier resin and, if necessary, the other components to one side of the substrate layer described below, and drying the applied resin composition if necessary. In this case, the desired laminate film itself or a part of the laminate film can be immediately obtained.

[0043] The resin composition may contain a solvent in order to improve its applicability for coating. Examples of the solvent include water, 2-propanol (IPA), ethanol, methanol, methyl ethyl ketone (MEK), ethyl acetate, toluene, and acetone.

[0044] The resin composition may contain only one type of solvent, or two or more types of solvents. When two or more types of solvents are contained, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0045] The method of producing the resin film by coating the resin composition in this manner is particularly effective when the target resin film contains a component that decomposes, ignites, or vaporizes at a relatively low temperature, etc. Examples of such components that are not suitable for handling at high temperatures include potassium sorbate and sodium lactate.

[0046] The resin composition may be applied by a known method, for example, by a method using various coaters.

[0047] The drying conditions for the resin composition are not particularly limited. When the resin composition contains a solvent described below, it is preferable to dry the resin composition by heating. In this case, it is preferable to dry the resin composition at, for example, 40 to 120°C.

[0048] <<Laminated film>> The configuration of a laminated film according to an embodiment of the present invention will be described. Fig. 1 is a schematic cross-sectional view of a laminated film 1 according to an embodiment of the present invention. As shown in Fig. 1, the laminated film 1 according to this embodiment is generally configured to include a resin film 2 according to the present invention and a base layer 3 provided on the resin film 2. The laminated film 1 according to this embodiment can be used as a package, particularly as a film for packaging metal articles such as medical devices, industrial materials, and electronic components.

[0049] <Base material layer> The base layer (also referred to as core layer) 3 is a resin layer provided on the above-mentioned resin film 2. The base layer 3 can impart flexibility to the multilayer film 1. Resins that can be used for the base layer 3 are not particularly limited as long as they are capable of imparting the above-mentioned functions and have moisture permeability, and examples of such resins include polyolefin resins, polyester resins, nylon resins, ethylene-vinyl acetate copolymers, and olefin elastomers. The base layer may or may not be porous as long as it has moisture permeability.

[0050] Examples of the polyolefin resin include polyethylene copolymers, polypropylene copolymers, and butene copolymers, and among these, polyethylene copolymers and polypropylene copolymers are preferred. From the viewpoint of improving adhesiveness, the copolymer may take the form of a random copolymer, a graft copolymer, a block copolymer or a graft copolymer, with a random copolymer being particularly preferred.

[0051] The polyolefin resin is an olefin copolymer. The polyethylene copolymer is a copolymer of ethylene and a monomer other than ethylene. The polypropylene copolymer is a copolymer of propylene and a monomer other than propylene. The butene copolymer is a copolymer of butene and a monomer other than butene.

[0052] The polyethylene copolymer is not particularly limited, but examples thereof include copolymers of ethylene and vinyl group-containing monomers.

[0053] Examples of copolymers of ethylene and vinyl group-containing monomers include maleic anhydride-grafted 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"), ionomer (hereinafter referred to as "ION resin"), ethylene-based thermoplastic elastomer, and the like. In this specification, the ION resin refers to a copolymer of ethylene and a small amount of acrylic acid or methacrylic acid, which is made to have an ionically crosslinked structure by forming a salt between the acid portion and a metal ion.

[0054] Specific examples of polyester resins include polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, and polyhexamethylene terephthalate.

[0055] 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, 6-nylon Examples of such a copolymer include a copolymer of nylon and 6T-nylon, a copolymer of nylon and 6I-nylon, a copolymer of nylon and 66-nylon and 610-nylon, a copolymer of nylon and 66-nylon and 12-nylon (nylon 6 / 66 / 12), a copolymer of nylon and 66-nylon and 612-nylon, a copolymer of nylon and 6T-nylon, a copolymer of nylon and 6I-nylon, a copolymer of nylon and 6T-nylon and 6I-nylon, a copolymer of nylon and 6T-nylon and 6I-nylon, and a copolymer of nylon and 6T-nylon and 6I-nylon, an amorphous nylon, etc. Among these, from the viewpoints of heat resistance, mechanical strength, and ease of availability, 6-nylon, 12-nylon, 66-nylon, nylon 6 / 66, nylon 6 / 12, and nylon 6 / 66 / 12 are preferred, and 6-nylon is more preferred.

[0056] The base material layer 3 may be a single layer or may be a multiple layer of two or more layers. For example, by forming the base material layer 3 from multiple layers of different materials, the properties of the base material layer 3, such as hardness and moisture permeability, can be adjusted.

[0057] The thickness ratio of the base layer 3 to the total layers of the laminated film 1 is preferably 75 to 99.9%, more preferably 90 to 99.9%, further preferably 95 to 99.9%, and particularly preferably 97 to 99.5%. When the thickness ratio is equal to or greater than the lower limit, flexibility can be imparted to the multilayer film 1. When the thickness ratio is equal to or less than the upper limit, a decrease in moisture permeability when a resin film is laminated is suppressed.

[0058] The thickness of the base layer 3 is preferably 10 to 100 μm, and more preferably 15 to 50 μm. When the thickness is equal to or greater than the lower limit of the preferred range, the decrease in moisture permeability when a resin film is laminated thereon is suppressed, and when the thickness is equal to or less than the upper limit, flexibility is obtained.

[0059] <Laminated film manufacturing method> Next, a method for producing the laminated film 1 described above will be described. The manufacturing method of the laminated film 1 of this embodiment is not particularly limited, but it can be manufactured, for example, by applying the resin composition for forming a resin film onto one side of a base layer, drying it as necessary, and laminating the resin film onto one side of the base layer.

[0060] <<Packaging and its manufacturing method>> A package can be produced by using the laminate film, placing the resin film on the side of an object to be packaged, and packaging the object. Since the packaging body is provided with the resin film, the contents in the packaging body can be dried after packaging, and since an inert gas is enclosed in the packaging body, deterioration of the contents can be prevented, which makes it possible to prevent deterioration due to rust, etc., of metal articles such as medical devices, industrial materials, and electronic components.

[0061] During packaging, for example, the object to be packaged is wrapped in one sheet of the laminate film, and the surplus portion of the laminate film (the portion not wrapping the object to be packaged) is overlapped with another portion of the laminate film and sealed, thereby packaging the object to be packaged. At this time, the resin films in the laminate film may be overlapped with each other, or the resin film and the base material layer may be overlapped. In addition, when packaging, for example, the object to be packaged can be sandwiched between two sheets of the laminate film, and these laminate films can be overlapped and sealed to package the object to be packaged. At this time, the resin films in the laminate film may be overlapped, or the resin film and the base material layer may be overlapped. Furthermore, the object can be packaged by placing the object on a tray and sealing the resin film in the laminated film to the periphery of the tray. EXAMPLES

[0062] 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.

[0063] [Example 1] <<Manufacture of resin films and laminated films>> A resin solution obtained by mixing an aqueous polyurethane (DIC Corporation's "Hydran WLS-230") (solid content concentration: 35% by mass) diluted with a solvent (a mixed solvent of water: 2-propanol = 8: 2) to a solid content concentration of 3% by mass and a titanium-based crosslinking agent (Matsumoto Fine Chemical Co., Ltd.'s "Orgatix TC400", component concentration: 79% by mass) 60 phr (60 parts by mass of Orgatix TC400 per 100 parts by mass of aqueous polyurethane) was applied to one side of a substrate film (3M Corporation's "Microporous Film", thickness 30 μm) and dried at 100 ° C. for 2 minutes to form a resin film (thickness 1.05 μm) on the substrate film. The resin solution corresponds to the resin composition for forming a resin film, and the substrate film corresponds to the substrate layer described above. In this manner, a laminate film was obtained in which the resin film was laminated on the base film.

[0064] [Example 2] <<Manufacture of resin films and laminated films>> A resin film (thickness 1.05 μm) was formed on a substrate film in the same manner as in Example 1, except that 50 phr (50 parts by mass of Orgatix TC400 per 100 parts by mass of aqueous polyurethane) of a titanium-based crosslinking agent ("Orgatix TC400" manufactured by Matsumoto Fine Chemical Co., Ltd.) was used instead of 60 phr. In this manner, a laminate film was obtained in which the resin film was laminated on the base film.

[0065] [Example 3] <<Manufacture of resin films and laminated films>> A resin film (thickness 1.05 μm) was formed on a substrate film in the same manner as in Example 1, except that 40 phr (40 parts by mass of Orgatix TC400 per 100 parts by mass of aqueous polyurethane) of a titanium-based crosslinking agent ("Orgatix TC400" manufactured by Matsumoto Fine Chemical Co., Ltd.) was used instead of 60 phr. In this manner, a laminate film was obtained in which the resin film was laminated on the base film.

[0066] [Example 4] <<Manufacture of resin films and laminated films>> A resin film (thickness 2.8 μm) was formed on a substrate film in the same manner as in Example 1, except that an aqueous polyurethane (DIC Corporation's "Hydran WLS-230") (solid concentration: 35% by mass) diluted with a solvent (a mixed solvent of water:2-propanol = 8:2) to a solid concentration of 8.1% by mass was used instead of an aqueous polyurethane (DIC Corporation's "Hydran WLS-230") (solid concentration: 35% by mass) diluted with a solvent (a mixed solvent of water:2-propanol = 8:2) to a solid concentration of 3% by mass, and a titanium-based crosslinker (Matsumoto Fine Chemical Co., Ltd.'s "Orgatix TC400") was used at 50 phr (50 parts by mass of Orgatix TC400 per 100 parts by mass of aqueous polyurethane) instead of 60 phr. In this manner, a laminate film was obtained in which the resin film was laminated on the base film.

[0067] [Example 5] <<Manufacture of resin films and laminated films>> A resin film (thickness 3.3 μm) was formed on a substrate film in the same manner as in Example 1, except that an aqueous polyurethane (DIC Corporation's "HYDRAN WLS-230") (solid concentration: 35% by mass) diluted with a solvent (a mixed solvent of water:2-propanol = 8:2) to a solid concentration of 9.5% by mass was used instead of an aqueous polyurethane (DIC Corporation's "HYDRAN WLS-230") (solid concentration: 35% by mass) diluted with a solvent (a mixed solvent of water:2-propanol = 8:2) to a solid concentration of 3% by mass. In this manner, a laminate film was obtained in which the resin film was laminated on the base film.

[0068] [Comparative Example 1] <<Manufacture of resin films and laminated films>> A resin film (thickness 1.05 μm) was formed on a substrate film in the same manner as in Example 1, except that 30 phr (30 parts by mass of Orgatix TC400 per 100 parts by mass of aqueous polyurethane) of a titanium-based crosslinking agent ("Orgatix TC400" manufactured by Matsumoto Fine Chemical Co., Ltd.) was used instead of 60 phr. In this manner, a laminate film was obtained in which the resin film was laminated on the base film.

[0069] [Comparative Example 2] <<Manufacture of resin films and laminated films>> A resin film (thickness 1.05 μm) was formed on a substrate film in the same manner as in Example 1, except that 20 phr (20 parts by mass of Orgatix TC400 per 100 parts by mass of aqueous polyurethane) of a titanium-based crosslinking agent ("Orgatix TC400" manufactured by Matsumoto Fine Chemical Co., Ltd.) was used instead of 60 phr. In this manner, a laminate film was obtained in which the resin film was laminated on the base film.

[0070] [Comparative Example 3] <<Manufacture of resin films and laminated films>> A resin film (thickness 1.05 μm) was formed on a substrate film in the same manner as in Example 1, except that 10 phr (10 parts by mass of Orgatix TC400 per 100 parts by mass of aqueous polyurethane) of a titanium-based crosslinking agent ("Orgatix TC400" manufactured by Matsumoto Fine Chemical Co., Ltd.) was used instead of 60 phr. In this manner, a laminate film was obtained in which the resin film was laminated on the base film.

[0071] <<Measurement of water vapor transmission rate of resin film>> The water vapor permeation amounts of the laminated films of Examples 1 to 5 and Comparative Examples 1 to 3 obtained above, and the base film used in the examples and comparative examples (3M's "Microporous Film", thickness 30 μm) were measured by the cup method specified in JIS Z 0208 under conditions of 30°C and 75% RH and 30°C and 45% RH. The measurements were carried out by putting 10 g of dried calcium chloride into a container with a diameter of 60 mm. Next, for the laminated films of Examples 1 to 5 and Comparative Examples 1 to 3, the water vapor permeation amount of the resin film not including the base film was calculated from the measured water vapor permeation amount of the laminated film using the following formula. The results are shown in Table 1.

[0072]

number

[0073] <<Measurement of air permeability resistance of resin film>> The air permeability resistance of the laminated films of Examples 1 to 5 and Comparative Examples 1 to 3 obtained above, and the base film used in the examples and comparative examples (3M's "Microporous Film", thickness 30 μm) was measured at 23°C and 50% humidity by the Oken method specified in JIS P 8117:2009. Next, for the laminated films of Examples 1 to 5 and Comparative Examples 1 to 3, the air permeability resistance of the resin film of each Example was calculated by subtracting the air permeability resistance of the laminated film of each Example from the air permeability resistance of the base film. The results are shown in Table 1.

[0074] <<Evaluation of resin film formation in laminated films>> The surfaces of the resin films (the exposed surfaces opposite to the substrate film side) of the laminate films of Examples 1 to 5 and Comparative Examples 1 to 3 obtained above were visually observed, and the state of formation of the resin film in the laminate films was evaluated according to the following evaluation criteria. <Evaluation criteria> A: The resin film is formed uniformly on the base film. B: There are some areas where the resin film is not formed uniformly on the base film, but overall the resin film is formed almost uniformly on the base film. C: The resin film is not uniformly formed on the base film, and most of the base film has regions where the resin film is not formed.

[0075] [Table 1]

[0076] As is clear from the above results, the resin films of Examples 1 to 5 have a water vapor transmission rate of 5,500 g / m2 at 30°C and 75% RH. 2 ·day or more, and the water vapor transmission rate at 30℃ and 45% RH is 3000g / m 2·days or more, and had excellent moisture permeability even in a high humidity environment or a low humidity environment. In addition, the air permeability resistance of the air was 5000 seconds or more, and therefore the gas barrier property was also excellent. Furthermore, the resin film formation state of the resin films of Examples 1, 4 and 5 was evaluated as "A", and the resin films of Examples 2 and 3 were evaluated as "B", and the resin film formation state was also excellent. In contrast, the resin films of Comparative Examples 1 to 3, in which the blending amount of the crosslinking agent was less than 35 parts by mass relative to 100 parts by mass of the aqueous polyurethane, were evaluated as "C", and the resin film formation state was poor, and the water vapor transmission rate could not be measured. That is, the moisture permeability could not be controlled in the resin films of Comparative Examples 1 to 3. In addition, the resin films of Comparative Examples 2 and 3, in which the blending amount of the crosslinking agent was 20 parts by mass and 10 parts by mass relative to 100 parts by mass of the aqueous polyurethane, respectively, had air permeability resistance of less than 5000 seconds, and therefore were also inferior in gas barrier property. [Industrial Applicability]

[0077] The present invention can be used for packaging metal articles such as medical equipment, industrial materials, and electronic components. [Explanation of symbols]

[0078] 1...Laminated film 2. Resin film 3...Base material layer

Claims

1. A resin film, The resin film contains an aqueous polyurethane and a crosslinking agent, the crosslinking agent is one or more selected from the group consisting of titanium compounds and metal chelate compounds, The resin film, wherein the blending amount of the crosslinking agent is 35 parts by mass or more per 100 parts by mass of the aqueous polyurethane.

2. 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 75% RH is 5,500 g / m ２ ・day or more, 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 3000 g / m ２ ・day or more, The resin film according to claim 1, wherein the air permeability resistance of the resin film is 5000 seconds or more at 23°C and 50% RH as measured by the Oken method specified in JIS P 8117:2009.

3. The resin film according to claim 1 or 2, wherein the resin film has a thickness of 0.1 μm or more and 4.0 μm or less.

4. A laminate film comprising the resin film according to claim 1 or 2 and a base layer provided on the resin film.

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