Laminated film

Abstract

To provide a laminated film having high moisture permeability and excellent mechanical strength.SOLUTION: A laminated film comprising a base material layer and a resin film provided on the base material layer, wherein a water vapor permeation amount of the base material layer under conditions of 40 °C. and 90% RH measured by a cup method specified in JISZ0208 is 5000g / m2·day or more, a water vapor permeation amount of the resin film is 5000g / m2·day or more, a water vapor permeation amount of the laminated film is 3000g / m2·day or more, and a dumbbell-shaped No. 1 test piece is produced using the laminated film in conformity with JIS K 7116-1:2014, A tensile strength when the dumbbell-shaped No. 1 test piece is elongated under conditions of 25 °C and a speed of 500mm / min is 2. 5MPa or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminated 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 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] Highly moisture-permeable substrate films have been known in the past (for example, Patent Document 1), but most highly moisture-permeable substrate films have many voids or are porous, which poses a problem of strength concerns, such as the risk of tearing during packaging. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese 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 laminated film having high moisture permeability and excellent mechanical strength. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention employs the following configuration. [1] A laminated film comprising a substrate layer and a resin film provided on the substrate layer, wherein the water vapor permeation amount of the substrate layer measured by the cup method specified in JIS Z 0208 under conditions of 40°C and 90% RH is 5000 g / m2 ·days or more, and the water vapor permeation amount of the resin film measured by the cup method specified in JIS Z 0208 under conditions of 40°C and 90% RH is 5000 g / m 2 ·days or more, and the water vapor permeation amount of the laminated film measured by the cup method specified in JIS Z 0208 under conditions of 40°C and 90% RH is 3000 g / m 2 a dumbbell-shaped No. 1 test piece is prepared using the laminated film in accordance with JIS K 7161-1:2014, and the dumbbell-shaped No. 1 test piece is elongated at 25°C at a rate of 500 mm / min, and the tensile strength of the dumbbell-shaped No. 1 test piece is 2.5 MPa or more. [2] The laminated film according to [1], wherein the resin film is porous. [3] The laminated film according to [1] or [2], wherein the resin film contains a resin having either a polyamide structure or a polyimide structure, or both of these structures. [4] The laminated film according to any one of [1] to [3], wherein the resin film has a thickness of 2 μm or more and 10 μm or less. [Effects of the Invention]

[0007] According to the present invention, a laminated film having high moisture permeability and excellent mechanical strength is provided. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing the configuration of a laminated film according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a laminated film according to an embodiment of the present invention will be described in detail. Note that the drawings used in the following description may show characteristic portions enlarged for the sake of convenience in order to make the characteristics easier to understand, and the dimensional proportions of the respective components may not necessarily be the same as those in reality.

[0010] <<Laminated film>> The laminated film of the present embodiment is a laminated film including a base layer and a resin film provided on the base layer, and the water vapor permeation amount of the base layer measured by the cup method specified in JIS Z 0208 under conditions of 40°C and 90% RH is 5000 g / m 2 ·days or more, and the water vapor permeation amount of the resin film measured by the cup method specified in JIS Z 0208 under conditions of 40°C and 90% RH is 5000 g / m 2 ·days or more, and the water vapor permeation amount of the laminated film measured by the cup method specified in JIS Z 0208 under conditions of 40°C and 90% RH is 3000 g / m 2 ·days or more, and a dumbbell-shaped No. 1 test piece is prepared using the laminated film in accordance with JIS K 7161-1:2014, and the dumbbell-shaped No. 1 test piece is elongated at 25°C and at a rate of 500 mm / min, and the tensile strength is 2.5 MPa or more. As a result, the laminated film of this embodiment has high moisture permeability and excellent mechanical strength.

[0011] The structure of the laminate film of this embodiment will be described. Fig. 1 is a cross-sectional schematic diagram of a laminate film 1 of this embodiment. As shown in Fig. 1, the laminate film 1 of this embodiment is generally configured to include a base layer 3 and a resin film 2 provided on the base layer 3. The laminate film 1 of this embodiment can be used as a packaging film, particularly for packaging metal articles such as medical devices, industrial materials, and electronic components.

[0012] <Moisture permeability of base layer> The moisture permeability of the substrate layer can be evaluated by the amount of water vapor transmitted under conditions of 40° C. and 90% RH (relative humidity 90%), measured by the cup method specified in JIS Z 0208.

[0013] The water vapor permeability of the substrate layer measured by the cup method specified in JIS Z 0208 under conditions of 40°C and 90% RH was 5000 g / m 2·day or more. When the water vapor transmission rate is equal to or more than the lower limit, the base layer has high moisture permeability.

[0014] The water vapor permeability is 5100 g / m 2 ·day or more is preferable, and 5200g / m 2 5300g / m 2 5400g / m 2 5500g / m 2 day or more, 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 / m 2 -day or more, and 12000g / m 2 When the water vapor transmission rate is equal to or greater than the lower limit, the substrate layer has higher moisture permeability. On the other hand, the water vapor permeability is 20000 g / m 2 ·day or less, and 18000g / m 2 15,000g / m 2 If the moisture permeability is increased too much, the gas barrier property may decrease, and the contents may deteriorate due to oxidation, but by keeping the water vapor transmission rate at or below the upper limit, it is possible to suppress the decrease in gas barrier property and achieve both the moisture permeability and gas barrier property of the base material layer.

[0015] The water vapor permeation rate can be adjusted by, for example, the type or content of the resin contained in the base layer, or the thickness of the base layer.

[0016] <Moisture permeability of resin film> The moisture permeability of the resin film can be evaluated by measuring the amount of water vapor transmitted by the cup method specified in JIS Z 0208 under conditions of 40° C. and 90% RH.

[0017] The water vapor permeability of the resin film measured by the cup method specified in JIS Z 0208 under conditions of 40°C and 90% RH was 5000 g / m 2 ·day or more. When the water vapor transmission rate is equal to or more than the lower limit, the resin film has high moisture permeability.

[0018] The water vapor permeability is 5100 g / m 2 ·day or more is preferable, and 5200g / m 2 5300g / m 2 5400g / m 2 5500g / m 2 day or more, 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 / m 2 -day or more, and 12000g / m 2 When the water vapor transmission rate is equal to or greater than the lower limit, the resin film has higher moisture permeability. On the other hand, the water vapor permeability is 20000 g / m 2 ·day or less, and 18000g / m 2 15,000g / m 2 If the moisture permeability is increased too much, the gas barrier property may decrease, and the contents may deteriorate due to oxidation, but by keeping the water vapor transmission rate at or below the upper limit, it is possible to suppress the decrease in gas barrier property and achieve both moisture permeability and gas barrier property of the resin film.

[0019] The water vapor permeation rate can be adjusted by, for example, the type or content of the resin contained in the resin film, the porosity of the resin film, or the thickness of the resin film.

[0020] <Moisture permeability of laminated film> The moisture permeability of the laminated film can be evaluated by measuring the amount of water vapor transmitted by the cup method specified in JIS Z 0208 under conditions of 40° C. and 90% RH.

[0021] The water vapor permeability of the laminated film measured by the cup method specified in JIS Z 0208 under conditions of 40°C and 90% RH was 3000 g / m 2 ·day or more. When the water vapor transmission rate is equal to or more than the above lower limit, the laminated film has high moisture permeability.

[0022] The water vapor permeability is 3500 g / m 2 ·day or more is preferable, and 4000g / m 2 4500g / m 2 5000g / m 2 5500g / m 2 day or more, 6000g / m 2 -day or more, and 7000g / m 2When the water vapor transmission rate is equal to or greater than the above lower limit, the laminated film has higher moisture permeability. On the other hand, the water vapor permeability is 18000 g / m 2 ·day or less, and 16000g / m 2 12000g / m 2 If the moisture permeability is increased too much, the gas barrier property may decrease, and the contents may deteriorate due to oxidation, but by keeping the water vapor transmission rate at or below the upper limit, the decrease in gas barrier property can be suppressed, and both the moisture permeability and the gas barrier property of the laminate film can be achieved.

[0023] The water vapor permeability can be adjusted by, for example, the water vapor permeability of the base material layer and the resin film.

[0024] <Mechanical strength of laminated film> The mechanical strength of the laminated film can be evaluated by the tensile strength measured in accordance with JIS K 7161-1:2014.

[0025] In accordance with JIS K 7161-1:2014, a dumbbell-shaped No. 1 test piece is prepared using the laminate film, and the dumbbell-shaped No. 1 test piece is stretched at 25°C and at a rate of 500 mm / min, and the tensile strength is 2.5 MPa or more. When the tensile strength is equal to or greater than the lower limit, the laminate film has excellent mechanical strength.

[0026] The tensile strength is preferably 2.6 MPa or more, more preferably 2.7 MPa or more, even more preferably 2.8 MPa or more, even more preferably 2.9 MPa or more, and particularly preferably 3.0 MPa or more. When the tensile strength is equal to or greater than the lower limit, the laminated film has better mechanical strength. On the other hand, the tensile strength may be 10 MPa or less. When the tensile strength is equal to or less than the upper limit, a package using the laminated film can be opened more easily.

[0027] The tensile strength can be adjusted by, for example, the type or content of the resin contained in the laminate film (for example, the base layer and the resin film).

[0028] <<Laminated film manufacturing method>> The method for manufacturing the laminated film of this embodiment is not particularly limited, but it can be manufactured, for example, by applying a resin composition for forming the resin film to one surface of the base layer, drying it as necessary, and laminating the resin film on one surface of the base layer.

[0029] <<Resin film>> The resin film is preferably porous (has a porous structure), which can further improve the moisture permeability of the resin film.

[0030] The diameter of the pores in the porous structure of the resin film is preferably 1 to 50,000 nm, more preferably 2 to 49,000 nm, and even more preferably 3 to 48,000 nm. When the diameter is equal to or greater than the lower limit, the moisture permeability of the resin film can be further improved. On the other hand, if the moisture permeability is increased too much, the gas barrier properties may decrease and the contents may deteriorate due to oxidation. However, by having the diameter be equal to or less than the upper limit, it is possible to achieve both the moisture permeability and the gas barrier properties of the resin film, and further improve the mechanical strength of the resin film.

[0031] The diameter of the pores in the porous structure of the resin film can be adjusted, for example, by changing the type of resin contained in the resin film to a functional resin, which will be described later.

[0032] The resin film preferably contains a resin having either or both of a polyamide structure and a polyimide structure (hereinafter, this resin may be referred to as a functional resin). By including the functional resin in the resin film, the moisture permeability and mechanical strength of the resin film can be further improved.

[0033] The functional resin contained in the resin film may be one type only, or may be two or more types. When two or more types are contained, the combination and ratio thereof can be selected arbitrarily depending on the purpose.

[0034] In the resin film, the content of the functional resin relative to the total mass of the resin film 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 content is equal to or more than the lower limit, the moisture permeability and mechanical strength of the resin film can be further improved. There is no particular upper limit to the ratio, and the ratio may be 100% by mass or less.

[0035] The resin film may contain only the functional resin (i.e., it may consist of the functional resin), or it may contain other components that do not fall under the category of functional resin (i.e., it may consist of the functional resin and the other components).

[0036] The other components contained in the resin film are not particularly limited and can be selected arbitrarily depending on the purpose.

[0037] Examples of the other components include resins other than the functional resins and 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, thermal 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. Examples of organic fibers include cellulose, and cellulose nanofibers (CNF) are preferably used.

[0038] The resin film may contain only one type of other component, or two or more types. When two or more types are contained, the combination and ratio thereof can be selected arbitrarily depending on the purpose.

[0039] The resin film may be composed of one layer (single layer) or two or more layers. When the resin film is composed 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.

[0040] The thickness of the resin film is preferably 2 μm or more and 10 μm or less, more preferably 2 μm or more and 6 μm or less, and even more preferably 3 μm or more and 5 μm or less. When the thickness is equal to or more than the lower limit, the resin film can be formed more uniformly on the substrate layer. When the thickness is equal to or less than the upper limit, the moisture permeability of the resin film can be further improved.

[0041] <<Resin film manufacturing method>> The resin film can be formed on the substrate layer by, for example, applying a resin composition containing the functional resin and, if necessary, the other components to one side of the substrate layer described below, and drying it as necessary. In this case, the desired laminate film itself or a part thereof can be immediately obtained.

[0042] 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.

[0043] 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 selected arbitrarily depending on the purpose.

[0044] The method of producing the resin film by coating the resin composition in this manner is particularly effective when the target resin film contains components that decompose, ignite, or vaporize at relatively low temperatures, such as potassium sorbate and sodium lactate.

[0045] The resin composition may be applied by a known method, for example, by a method using various coaters.

[0046] The drying conditions for the resin composition are not particularly limited, but when the resin composition contains the above-mentioned solvent, it is preferable to heat-dry it, and in this case, it is preferable to dry it at, for example, 40 to 120°C.

[0047] <<Base material layer>> The substrate layer (also referred to as substrate film) is a resin layer provided on the above-mentioned resin film. The substrate layer can impart flexibility to the laminated film. Resins that can be used for the substrate layer are not particularly limited as long as they are capable of imparting the above-mentioned functions and have moisture permeability, and examples thereof include polyolefin resins, polyester resins, nylon resins, and olefin elastomers. The substrate layer may be porous or non-porous as long as it has moisture permeability, but if it is porous, it is preferable that its porous structure is different from that of the resin film.

[0048] The polyolefin resin is an olefin copolymer. 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 be in the form of a random copolymer, a graft copolymer, a block copolymer or a graft copolymer, with a random copolymer being particularly preferred.

[0049] 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.

[0050] The polyethylene copolymer is not particularly limited, but examples thereof include copolymers of ethylene and vinyl group-containing monomers.

[0051] 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"), and ethylene-based thermoplastic elastomer. In this specification, the term "ION resin" refers to a copolymer of ethylene and a small amount of acrylic acid or methacrylic acid, which has an ionically crosslinked structure formed by forming a salt between the acid moiety and a metal ion.

[0052] Specific examples of polyester resins include polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, and polyhexamethylene terephthalate.

[0053] 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 nylon include a copolymer of nylon and 6T-nylon, a copolymer of nylon 6 and 6I-nylon, a copolymer of nylon 6, 66-nylon, and 610-nylon, a copolymer of nylon 6, 66-nylon, and 12-nylon (nylon 6 / 66 / 12), a copolymer of nylon 6, 66-nylon, and 612-nylon, a copolymer of nylon 66 and 6T-nylon, a copolymer of nylon 66 and 6I-nylon, a copolymer of nylon 6T-nylon and 6I-nylon, a copolymer of nylon 66, 6T-nylon, and 6I-nylon, and amorphous nylon. 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, with 6-nylon being more preferred.

[0054] The base material layer may be a single layer or may be a multi-layer structure of two or more layers. For example, by forming the base material layer from multiple layers of different materials, the hardness, moisture permeability, and other properties of the base material layer can be adjusted.

[0055] The thickness ratio of the base layer to the total thickness of the laminated film 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%. When the thickness ratio is equal to or greater than the lower limit, flexibility can be imparted to the laminated film.When the thickness ratio is equal to or less than the upper limit, a decrease in moisture permeability when the resin film is laminated is suppressed.

[0056] The thickness of the substrate layer is preferably 10 to 100 μm, more preferably 50 to 100 μm. When the thickness is equal to or greater than the lower limit of the preferred range, a decrease in moisture permeability when the resin film is laminated thereon is suppressed, and when the thickness is equal to or less than the upper limit, flexibility is obtained.

[0057] The substrate layer can be produced, for example, by extrusion molding the resin or a resin composition containing the resin. [Example]

[0058] 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.

[0059] [Example 1] <<Manufacturing of resin films and laminated films>> A solution of polyamideimide (with a porous structure) was applied to one side of a substrate film ("20351FLV" manufactured by Unitika Ltd., thickness 60 μm, corresponding to the substrate layer) and dried at 130° C. for 4 minutes to form a resin film (thickness 4 μm) on the substrate film. The resin solution corresponds to the resin composition for forming the resin film, and the substrate film corresponds to the substrate layer described above. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0060] [Example 2] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 1, except that the thickness of the resin film was changed from 4 μm to 3 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0061] [Example 3] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 1, except that the thickness of the resin film was changed from 4 μm to 5 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0062] [Example 4] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 1, except that the thickness of the resin film was changed from 4 μm to 10 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0063] [Example 5] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 1, except that a substrate film ("20451FLV" manufactured by Unitika Ltd., thickness 80 μm) was used instead of the substrate film ("20351FLV" manufactured by Unitika Ltd., thickness 60 μm). In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0064] [Example 6] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 5, except that the thickness of the resin film was changed from 4 μm to 3 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0065] [Example 7] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 5, except that the thickness of the resin film was changed from 4 μm to 5 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0066] [Example 8] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 5, except that the thickness of the resin film was changed from 4 μm to 10 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0067] [Example 9] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 1, except that a substrate film ("20551FLV" manufactured by Unitika Ltd., thickness 90 μm) was used instead of the substrate film ("20351FLV" manufactured by Unitika Ltd., thickness 60 μm). In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0068] [Example 10] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 9, except that the thickness of the resin film was changed from 4 μm to 3 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0069] [Example 11] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 9, except that the thickness of the resin film was changed from 4 μm to 5 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0070] [Example 12] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 9, except that the thickness of the resin film was changed from 4 μm to 10 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0071] [Example 13] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 1, except that the thickness of the resin film was changed from 4 μm to 15 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0072] [Example 14] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 1, except that polyimide (with porous structure) was used instead of polyamideimide (with porous structure) and the thickness of the resin film was changed from 4 μm to 2 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0073] [Example 15] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 1, except that polyamide (with porous structure) was used instead of polyamideimide (with porous structure) and the thickness of the resin film was changed from 4 μm to 10 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0074] [Example 16] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 1, except that polyamide (without a porous structure) was used instead of polyamideimide (with a porous structure) and the thickness of the resin film was changed from 4 μm to 1 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0075] [Comparative Example 1] <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 1, except that polyimide (without a porous structure) was used instead of polyamideimide (with a porous structure) and the thickness of the resin film was changed from 4 μm to 2 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0076] Comparative Example 2 <<Manufacturing of resin films and laminated films>> A resin film was formed on a substrate film in the same manner as in Example 1, except that polyvinyl alcohol (without a porous structure) was used instead of polyamideimide (with a porous structure) and the thickness of the resin film was changed from 4 μm to 1 μm. In this way, a laminated film was obtained in which the resin film was laminated on the base film.

[0077] <<Water vapor transmission rate measurement>> The water vapor permeation rates of the laminate films of Examples 1 to 16 and Comparative Examples 1 and 2 obtained above, as well as the base films used in the examples and comparative examples, were measured at 40°C and 90% RH using the cup method specified in JIS Z 0208. Measurements were carried out by placing 10 g of dried calcium chloride in a 60 mm diameter container. The water vapor permeation rate of the resin film not including the base film was then calculated from the measured water vapor permeation rates of the laminate films using the following formula. The results are shown in Table 1.

[0078]

number

[0079] <<Tensile strength measurement>> In accordance with JIS K 7161-1:2014, dumbbell-shaped No. 1 test pieces were prepared using the laminate films of Examples 1 to 16 and Comparative Examples 1 and 2 obtained above, and the tensile strength of the dumbbell-shaped No. 1 test pieces was measured when they were stretched at 25°C and a rate of 500 mm / min. The results are shown in Table 1.

[0080] <<Evaluation of the resin film formation state in laminated films>> The surfaces of the resin films (exposed surfaces opposite to the substrate film side) of the laminate films of Examples 1 to 16 and Comparative Examples 1 and 2 obtained above were visually observed, and the state of resin film formation 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 formed uniformly on the base film, and there are regions in most parts of the base film where the resin film is not formed.

[0081] [Table 1]

[0082] As is clear from the above results, the laminated films of Examples 1 to 16 have a water vapor permeation rate of 5000 g / m 2 of the base film under conditions of 40°C and 90% RH. 2 The water vapor permeability of the resin film at 40°C and 90% RH is 5000g / m 2 The water vapor permeability of the laminated film at 40°C and 90% RH is 3000g / m 2The laminated film met the tensile strength requirement of 2.5 MPa or more, and had high moisture permeability and excellent mechanical strength.

[0083] Furthermore, the laminate films of Examples 1 to 12, 14 and 15 were evaluated as "A" for the state of resin film formation, while the laminate films of Examples 13 and 16 were evaluated as "B" for the state of resin film formation, and the state of resin film formation was also excellent.

[0084] In contrast, the laminated film of Comparative Example 1 had a water vapor permeation rate of 5000 g / m 2 at 40°C and 90% RH. 2 ·days, and the water vapor permeation rate of the laminated film under the conditions of 40°C and 90% RH is 3000 g / m 2 The tensile strength of the laminated film was less than 2.5 MPa, the moisture permeability was low, and the mechanical strength was also poor.

[0085] The laminated film of Comparative Example 2 had a tensile strength of less than 2.5 MPa, indicating poor mechanical strength. The resin film formation state was also poor, with an evaluation of "C." [Industrial Applicability]

[0086] The present invention can be used to package metal articles such as medical devices, industrial materials, and electronic components. [Explanation of symbols]

[0087] 1...Laminated film 2...Resin film 3…Base material layer

Claims

1. A laminated film comprising a base layer and a resin film provided on the base layer, The water vapor permeation amount of the substrate layer measured by the cup method specified in JIS Z 0208 under conditions of 40°C and 90% RH is 5000 g / m ２ ・day or more, The water vapor permeation amount of the resin film measured by the cup method specified in JIS Z 0208 under conditions of 40°C and 90% RH is 5000 g / m ２ ・day or more, The water vapor permeation amount of the laminated film measured by the cup method specified in JIS Z 0208 under conditions of 40°C and 90% RH is 3000 g / m ２ ・day or more, A dumbbell-shaped No. 1 test piece is prepared using the laminated film in accordance with JIS K 7161-1:2014, and the dumbbell-shaped No. 1 test piece is stretched at 25°C and at a rate of 500 mm / min, whereby the tensile strength of the laminated film is 2.5 MPa or more.

2. The laminated film according to claim 1 , wherein the resin film is porous.

3. The laminate film according to claim 1 or 2, wherein the resin film contains a resin having either or both of a polyamide structure and a polyimide structure.

4. 3. The laminated film according to claim 1, wherein the resin film has a thickness of 2 μm or more and 10 μm or less.

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