Laminated film

Abstract

To provide a film with excellent hygroscopic dimensional stability.SOLUTION: A laminate film having at least a base film (X) and a water vapor barrier layer (Y) is provided, where the base film (X) is a semi-aromatic polyamide film and the water vapor transmission coefficient of the laminate film at 40°C×90% RH measured according to the JIS K7129-1 method is 5 g / (m2-d) or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminated film having a base film and a water vapor barrier layer. [Background technology]

[0002] In recent years, the practical application of LED displays using light-emitting diode (LED) elements and organic electroluminescent (EL) displays using organic electroluminescent (EL) elements has been progressing. Conventionally, glass substrates have been used for mounting these elements, but with the demand for even thinner, lighter, and more flexible substrates, the adoption of resin film substrates is being considered. LED substrates are required to have high heat resistance so that they can withstand the high temperatures during soldering of LED elements and during LED illumination. Furthermore, they are required to have a low thermal shrinkage rate so that they do not easily change dimensions at high temperatures. From this perspective, the use of semi-aromatic polyamide films as materials for LED substrates has been considered. For example, Patent Document 1 discloses a semi-aromatic polyamide film that can be suitably used as a substrate for display materials. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2020 / 230806 [Overview of the project] [Problems that the invention aims to solve]

[0004] If dimensional changes occur in the circuit board after the circuit is formed on the LED board but before the solder is applied, a discrepancy may occur between the intended LED mounting position on the circuit and the actual solder mounting position. If a discrepancy occurs, it may not be possible to mount the LED element on the board, or even if it is mounted, it may result in poor electrical contact with the element. Dimensional changes are greatly affected by moisture absorption, and in processes using solder powder in particular, it is difficult to maintain a low-humidity environment from the standpoint of avoiding the risk of dust explosions, making moisture-induced dimensional changes in the board even more pronounced. The object of the present invention is to provide a film with excellent moisture absorption dimensional stability that can be used as an LED mounting substrate. [Means for solving the problem]

[0005] The inventors of this invention conducted extensive research to solve the aforementioned problems and, as a result, discovered that a laminated film having low water vapor permeability can solve the above problems, thus completing the present invention. In other words, the gist of the present invention is as follows.

[0006] (1) A laminated film having at least a base film (X) and a water vapor barrier layer (Y), wherein the base film (X) is a semi-aromatic polyamide film, and the water vapor transmission rate of the laminated film at 40°C × 90%RH measured in accordance with JIS K7129-1 is 5 g / (m²). 2 • A laminated film characterized by being as follows: (2) The laminated film according to (1), characterized in that the moisture-absorbing elongation in the longitudinal direction and the moisture-absorbing elongation in the width direction of the laminated film, measured when the humidity environment is changed from 23℃ × 50%RH to 23℃ × 90%RH, are each 0.2% or less. (3) The laminated film according to (1) or (2), characterized in that it has a water vapor barrier layer (Y) on the first surface side of the base film (X), and also has a water vapor barrier layer (Y) on the second surface side of the base film (X). (4) The laminated film according to any one of (1) to (3), characterized in that the semi-aromatic polyamide film is biaxially oriented. (5) A laminated film according to any one of (1) to (4), characterized in that a base film (X) and a water vapor barrier layer (Y) are adjacent to each other. (6) A copper-clad laminate containing the laminated film described in any of (1) to (5) above. (7) An LED mounting board using a laminated film as described in any of (1) to (5) above. (8) An LED display using the LED mounting board described in (7) above. [Effects of the Invention]

[0007] The laminated film of the present invention can be suitably used as an LED mounting substrate for flexible LED displays, an optical substrate such as an organic EL, an electronic substrate material such as a flexible printed circuit board or a flexible flat cable, and a cover-lay film for flexible printed circuit boards. [Modes for carrying out the invention]

[0008] The present invention will be described in detail below. The laminated film of the present invention is a laminated film having at least a base film (X) and a water vapor barrier layer (Y), wherein the base film (X) is a semi-aromatic polyamide film, and the water vapor transmission rate of the laminated film at 40°C × 90%RH measured in accordance with JIS K7129-1 is 5 g / (m²). 2 d) The following:

[0009] <Base film (X)> The base film (X) constituting the laminated film of the present invention is a semi-aromatic polyamide film. Semi-aromatic polyamide has an excellent balance of mechanical properties such as heat resistance and flexibility, and the film obtained by forming a film of semi-aromatic polyamide is transparent.

[0010] (Semi-aromatic polyamide) In the present invention, the semi-aromatic polyamide constituting the semi-aromatic polyamide film is composed of a dicarboxylic acid component and a diamine component, and has an aromatic component in either the dicarboxylic acid component or the diamine component.

[0011] The dicarboxylic acid component constituting the semi-aromatic polyamide preferably has terephthalic acid as the main component, and the proportion of terephthalic acid in the dicarboxylic acid component is preferably 60 to 100 mol%. Examples of the dicarboxylic acid component other than terephthalic acid include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, octadecanedioic acid, and aromatic dicarboxylic acids such as 1,4-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,2-naphthalenedicarboxylic acid, and isophthalic acid.

[0012] The diamine component constituting the semi-aromatic polyamide preferably has an aliphatic diamine having 4 to 15 carbon atoms as the main component. The proportion of the aliphatic diamine having 4 to 15 carbon atoms in the diamine component is preferably 60 to 100 mol%. Examples of the aliphatic diamine having 4 to 15 carbon atoms include 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 2-methyl-1,8-octanediamine, 4-methyl-1,8-octanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,14-tetradecanediamine, 1,15-pentadecanediamine, etc. These may be used alone or in combination of two or more.

[0013] Preferred semi-aromatic polyamides include those composed of a dicarboxylic acid component consisting only of terephthalic acid (100 mol% of terephthalic acid) and a diamine component containing 60 to 100 mol% in total of 1,9-nonanediamine and 2-methyl-1,8-octanediamine in the diamine component, and those composed of a dicarboxylic acid component consisting only of terephthalic acid (100 mol% of terephthalic acid) and a diamine component containing 1,10-decanediamine.

[0014] In the semi-aromatic polyamide, lactams such as ε-caprolactam, ζ-enanthlactam, η-capryllactam, ω-laurolactam, etc. may be copolymerized as long as the object of the present invention is not impaired.

[0015] The type of monomer and the copolymerization ratio constituting the semi-aromatic polyamide are preferably selected so that the melting point (Tm) of the obtained semi-aromatic polyamide is in the range of 270 to 350°C. When the Tm of the semi-aromatic polyamide is within the above range, thermal decomposition during film processing can be efficiently suppressed. If the Tm is less than 270°C, the obtained film may have insufficient heat resistance. On the other hand, if the Tm exceeds 350°C, thermal decomposition may occur during film production.

[0016] The intrinsic viscosity of the semi-aromatic polyamide is preferably 0.8 to 2.0 dL / g, and more preferably 0.9 to 1.8 dL / g. When the intrinsic viscosity of the semi-aromatic polyamide is 0.8 dL / g or more, a film with excellent mechanical strength can be produced. However, if it exceeds 2.0 dL / g, it may be difficult to produce the film.

[0017] The semi-aromatic polyamide may contain a polymerization catalyst and a terminal blocking agent. Examples of the terminal blocking agent include acetic acid, lauric acid, benzoic acid, octylamine, cyclohexylamine, and aniline. Examples of the polymerization catalyst include phosphoric acid, phosphorous acid, hypophosphorous acid, or their salts. [[ID=B]]

[0018] (Semi-aromatic polyamide film) The semi-aromatic polyamide film constituting the laminated film of the present invention preferably has a thickness of 20 μm or more, more preferably 30 μm or more, and even more preferably 50 μm or more. When the thickness of the semi-aromatic polyamide film is 20 μm or more, it is possible to prevent the deflection of the entire laminate when an LED element is mounted. Furthermore, the semi-aromatic polyamide film preferably has a thickness of 200 μm or less, more preferably 160 μm or less, and even more preferably 90 μm or less. A thickness of 200 μm or less facilitates handling during roll-to-roll processing and suppresses an increase in the overall thickness of the LED mounting substrate when applied to an LED mounting substrate.

[0019] The semi-aromatic polyamide film is preferably uniaxially oriented, and more preferably biaxially oriented.

[0020] The semi-aromatic polyamide film may be a single-layer film consisting of one type of layer, or a multilayer structure consisting of two or more layers laminated together. In the case of a multilayer structure, for example, in a two-layer film, a lubricant can be included in any one of the two layers, and in a three-layer film, a lubricant can be included in each of the layers located on both surfaces. The type and amount of lubricant to be included can be designed independently for each layer. By using such a multilayer structure, the surface roughness of each surface of the semi-aromatic polyamide film can be controlled independently.

[0021] The surface of the semi-aromatic polyamide film may be laminated with an easy-adhesion layer, or subjected to corona treatment, plasma treatment, acid treatment, flame treatment, etc., to improve adhesion with other materials.

[0022] In addition to the water vapor barrier layer (Y), the semi-aromatic polyamide film may also have layers of inorganic materials such as metals or their oxides, other polymers, paper, woven fabrics, nonwoven fabrics, wood, etc. laminated to it.

[0023] The semi-aromatic polyamide film may contain fine particles for purposes such as improving its slipperiness. The semi-aromatic polyamide film can use either inorganic or organic fine particles.

[0024] Examples of inorganic fine particles contained in the semi-aromatic polyamide film include silica, alumina, titanium dioxide, calcium carbonate, kaolin, and barium sulfate. Examples of organic fine particles include acrylic resin particles, melamine resin particles, silicone resin particles, and cross-linked polystyrene particles. Among these, silica fine particles and acrylic resin particles are preferred due to their good dispersibility and handling properties in the film. The average particle size of the fine particles is preferably 0.05 to 5.0 μm, and more preferably 0.1 to 4.0 μm. The content of fine particles is preferably 0 to 0.2% by mass, more preferably 0.01 to 0.2% by mass, and even more preferably 0.02 to 0.1% by mass. Furthermore, the slipperiness of the film can be efficiently improved when the content of fine particles with an average particle size of 0.05 to 2.0 μm is 0.2% by mass or less, and when the content of fine particles with an average particle size of 2.1 to 5.0 μm is 0.1% by mass or less. It is also possible to use a combination of two or more types of fine particles with different average particle sizes. As described above, the average particle size and content of fine particles can be selected according to the required properties of the film, such as friction characteristics, optical properties, and other characteristics, and can be added within a range that does not impair transparency.

[0025] In addition to the fine particles, the semi-aromatic polyamide film may optionally contain additives such as lubricants, colorants such as pigments and dyes including titanium, color inhibitors, heat stabilizers, antioxidants such as hindered phenols, phosphate esters and phosphite esters, weather-resistant modifiers such as benzotriazole compounds, brominated and phosphorus-based flame retardants, plasticizers, mold release agents, reinforcing agents such as talc, modifiers, antistatic agents, ultraviolet absorbers, antifogging agents, and various polymer resins.

[0026] Various methods can be used to incorporate the above-mentioned fine particles and additives into the film. Representative methods include the following: (A) Method of adding during polymerization of semi-aromatic polyamides (B) A method in which a masterbatch pellet is prepared by directly adding it to a semi-aromatic polyamide and melt-kneading it, and the masterbatch pellet is added during film formation and melt-kneaded in an extruder. (C) A method in which the semi-aromatic polyamide is directly added during film formation and melt-kneaded in an extruder. (D) Method of adding directly to the extruder during film formation and melt-mixing.

[0027] (Method for manufacturing semi-aromatic polyamide films) The method for producing the semi-aromatic polyamide film constituting the laminated film of the present invention is not particularly limited, but it can be produced by, for example, the following method.

[0028] Commercially available products can be suitably used as semi-aromatic polyamides for manufacturing semi-aromatic polyamide films. Examples of such commercial products include "Genesta®" manufactured by Kuraray Co., Ltd., "Zecot®" manufactured by Unitika Corporation, "Lenny®" manufactured by Mitsubishi Engineering Plastics Corporation, "Arlen®" manufactured by Mitsui Chemicals, Inc., "Ultramid®" manufactured by BASF, and Nylon MXD6 manufactured by Mitsubishi Gas Chemical Company.

[0029] Furthermore, semi-aromatic polyamides can be produced using methods known for producing crystalline polyamides. Examples include solution polymerization or interfacial polymerization using acid chloride and a diamine component as raw materials (Method A), or a method of producing a low polymer using a dicarboxylic acid component and a diamine component as raw materials and increasing the molecular weight of the low polymer by melt polymerization or solid-phase polymerization (Method B), a method of producing a crushed mixture of salt and low polymer using a dicarboxylic acid component and a diamine component as raw materials and solid-phase polymerization therein (Method C), and a method of producing a salt using a dicarboxylic acid component and a diamine component as raw materials and solid-phase polymerization therein (Method D). Among these, Methods C and D are preferred, and Method D is more preferred. Compared to Method B, Methods C and D can produce the salt and crushed mixture of low polymer and the salt at low temperatures, and do not require a large amount of water when producing the salt and crushed mixture of low polymer and the salt. Therefore, the generation of gel-like material can be reduced, and fish eyes can be reduced.

[0030] In method B, for example, a nylon salt prepared by mixing a diamine component, a dicarboxylic acid component, and a polymerization catalyst together can be heated and polymerized at a temperature of 200 to 250°C to obtain a low polymer. The intrinsic viscosity of the low polymer is preferably 0.1 to 0.6 dL / g. Setting the intrinsic viscosity of the low polymer within this range has the advantage of preventing disruption of the molar balance between carboxyl groups in the dicarboxylic acid component and amino groups in the diamine component during subsequent solid-phase polymerization or melt polymerization, thereby increasing the polymerization rate. If the intrinsic viscosity of the low polymer is less than 0.1 dL / g, the polymerization time will be longer, which may result in lower productivity. On the other hand, if it exceeds 0.6 dL / g, the resulting semi-aromatic polyamide may become discolored. Solid-phase polymerization of low polymers is preferably carried out under reduced pressure or under inert gas flow. Furthermore, the solid-phase polymerization temperature is preferably 200-280°C. By setting the solid-phase polymerization temperature within this range, discoloration and gelation of the resulting semi-aromatic polyamide can be suppressed. If the solid-phase polymerization temperature is below 200°C, the polymerization time will be longer, which may result in lower productivity. On the other hand, if the temperature exceeds 280°C, discoloration and gelation may occur in the resulting semi-aromatic polyamide. The melt polymerization of low polymers is preferably carried out at a temperature of 350°C or lower. If the polymerization temperature exceeds 350°C, decomposition and thermal degradation of the semi-aromatic polyamide may be accelerated. As a result, films obtained from such semi-aromatic polyamides may have inferior strength and appearance. The above-mentioned melt polymerization also includes melt polymerization using a melt extruder.

[0031] In method C, for example, a suspension consisting of a molten aliphatic diamine and a solid aromatic dicarboxylic acid is stirred and mixed to obtain a mixture. Then, in this mixture, at a temperature below the melting point of the final semi-aromatic polyamide, a reaction to produce a salt by the reaction of the aromatic dicarboxylic acid and the aliphatic diamine, and a reaction to produce a low polymer by polymerization of the produced salt are carried out to obtain a mixture of salt and low polymer. In this case, crushing may be carried out while the reaction is in progress, or crushing may be carried out after the reaction has been completed and the product has been removed. The obtained reaction product is then subjected to solid-phase polymerization at a temperature below the melting point of the final semi-aromatic polyamide to increase its molecular weight to a predetermined molecular weight and obtain a semi-aromatic polyamide. Solid-phase polymerization is preferably carried out in an inert gas stream such as nitrogen at a polymerization temperature of 180 to 270°C for a reaction time of 0.5 to 10 hours.

[0032] In method D, for example, aromatic dicarboxylic acid powder is heated to a temperature above the melting point of the aliphatic diamine and below the melting point of the aromatic dicarboxylic acid. An aliphatic diamine is then added to the aromatic dicarboxylic acid powder at this temperature, without substantially containing water, in order to maintain the powder state of the aromatic dicarboxylic acid, to produce a salt. The resulting salt is then solid-phase polymerized at a temperature below the melting point of the final semi-aromatic polyamide to increase its molecular weight to a predetermined level, thereby obtaining a semi-aromatic polyamide. Solid-phase polymerization is preferably carried out in an inert gas stream such as nitrogen at a polymerization temperature of 180 to 270°C for a reaction time of 0.5 to 10 hours.

[0033] The raw materials for the semi-aromatic polyamide film may be a mixture of the above-mentioned virgin raw materials, a mixture of off-spec film or scrap generated as edge trim during the production of the semi-aromatic polyamide film, or a mixture of virgin raw materials with the scrap mixture. These mixtures can be carried out by known methods such as dry blending using known equipment, or a kneading method in which melt-kneading is performed using a single-screw or twin-screw extruder.

[0034] In a method for producing a semi-aromatic polyamide film, the unstretched semi-aromatic polyamide resin used in the stretching process can be produced by melting and mixing the semi-aromatic polyamide resin in an extruder at a temperature of 280 to 340°C for 3 to 15 minutes, extruding it into a sheet through a T-die, and then cooling this sheet by bringing it into close contact with a cooling roll whose temperature is controlled to 30 to 40°C.

[0035] In a method for producing a semi-aromatic polyamide film, the unstretched film is preferably uniaxially stretched, and more preferably biaxially stretched. Stretching causes the semi-aromatic polyamide resin to undergo oriented crystallization. The stretching method is not particularly limited, but methods such as flat sequential biaxial stretching, flat simultaneous biaxial stretching, and tubular stretching can be used. Among these, flat sequential biaxial stretching and flat simultaneous biaxial stretching are optimal because they yield films with good thickness accuracy. Examples of stretching devices used in employing the flat-type simultaneous biaxial stretching method include screw-type tenters, pantograph-type tenters, and linear motor-driven clip-type tenters.

[0036] In the present invention, the semi-aromatic polyamide film exhibits higher dimensional stability due to moisture absorption as the residual stress increases, but its thermal dimensional stability decreases. Therefore, it is important to manufacture the film by adjusting the conditions shown below, such as the stretching conditions and heat setting conditions, to achieve a balance between dimensional stability due to moisture absorption and thermal dimensional stability.

[0037] The stretch ratio is preferably 2.0 to 3.5 times in the longitudinal direction (MD) and 2.0 to 4.0 times in the width direction (TD), and more preferably 2.5 to 3.5 times in the longitudinal direction and 3.0 to 4.0 times in the width direction. If the stretching ratio in the longitudinal direction exceeds 3.5 times, the resulting stretched film may undergo excessive crystallization, leading to a decrease in stretchability in the width direction. Even if stretching in the width direction is achieved, the resulting stretched film is prone to stretching unevenness, which can result in reduced thickness accuracy, decreased longitudinal tensile strength, and reduced transparency. On the other hand, if the stretch ratio in the width direction exceeds 4.0 times, transparency decreases, the thermal shrinkage rate increases, dimensional stability decreases, and tensile strength may further decrease. If the stretching ratio in the longitudinal and width directions is less than 2.0 times, stretching unevenness is likely to occur, resulting in thickness unevenness and a decrease in flatness.

[0038] The stretching speed is preferably such that the stretching strain rate in both the longitudinal and width directions exceeds 400% / min, more preferably between 800 and 12000% / min, and even more preferably between 1200 and 6000% / min. If the strain rate is 400% / min or less, crystals may grow during stretching, causing the film to break. Conversely, if the strain rate is too fast, the unstretched film may not be able to keep up with the deformation and may break. The stretching temperature is preferably above the glass transition temperature (Tg) of the semi-aromatic polyamide resin, and more preferably above Tg and below (Tg + 50°C). If the stretching temperature is below Tg, the film is prone to breakage and stable manufacturing cannot be achieved. Conversely, if it exceeds (Tg + 50°C), stretching irregularities may occur in the film.

[0039] It is preferable to perform a heat-setting treatment on the semi-aromatic polyamide film after the stretching described above, while holding the film with the clips used during stretching. By performing the heat-setting treatment, the resulting film can have its thermal shrinkage rate reduced without the occurrence of heat-induced unevenness. The heat-setting treatment temperature is preferably 260 to 280°C, more preferably 263 to 278°C, and even more preferably 265 to 275°C. If the heat-setting treatment temperature is below 260°C, the resulting film will have a high thermal shrinkage rate. If the heat-setting treatment temperature exceeds 280°C, the resulting film will have reduced tensile strength, be prone to appearance defects due to heat-induced wrinkles, and in some cases, may break during the heat-setting treatment, making it difficult to obtain a biaxially oriented film.

[0040] Examples of known heat-setting methods include blowing hot air, irradiating with infrared rays, and irradiating with microwaves. Among these, blowing hot air is preferred because it allows for uniform and precise heating.

[0041] After heat-setting, the film may be subjected to a heat-relaxation treatment at the same temperature as the heat-setting treatment while still held in place by the clip. By performing the relaxation treatment, a film with reduced thermal shrinkage can be obtained. The relaxation rate in the longitudinal direction is preferably 10% or less, more preferably 6% or less, and even more preferably 3% or less. Furthermore, the relaxation rate in the width direction is preferably 12% or less, and more preferably 6% or less. If the relaxation rate in the longitudinal direction exceeds 10%, or if the relaxation rate in the width direction exceeds 12%, sagging may occur in the film, and the moisture-absorbing elongation rate may increase. Furthermore, it is preferable that the relaxation rate in the width direction be 1% or more. If the relaxation rate in the width direction is less than 1%, it may not be possible to obtain a film with sufficiently reduced thermal shrinkage.

[0042] It is preferable to cool the film after heat setting treatment, or, if heat relaxation treatment has been performed, the film after heat relaxation treatment, while still being held in the clip, at a temperature lower than the temperature used in the heat setting treatment or heat relaxation treatment. By performing the cooling treatment, it is possible to prevent a rapid drop in temperature from the high temperature used in the heat setting treatment or heat relaxation treatment to room temperature (rapid cooling), thereby increasing the crystallinity of the resulting semi-aromatic polyamide film and improving its bending rigidity. The cooling temperature is preferably 110°C or higher, and more preferably 120°C or higher. On the other hand, the cooling temperature is preferably 150°C or lower, and more preferably 140°C or lower. If the cooling temperature exceeds 150°C, the temperature difference between the cooling temperature and room temperature becomes large, and the film is rapidly cooled to room temperature in subsequent processes. As a result, the degree of crystallinity of the resulting semi-aromatic polyamide film cannot be sufficiently increased. The holding time is preferably 0.5 to 25 seconds, more preferably 1 to 20 seconds, and even more preferably 2 to 15 seconds.

[0043] Furthermore, in apparatus for manufacturing semi-aromatic polyamide films, it is preferable that the surfaces of the cylinder, barrel melting section, metering section, single pipe, filter, T-die, etc., are treated to reduce surface roughness in order to prevent resin accumulation. Methods for reducing surface roughness include, for example, modifying the surface with a low-polarity substance, or depositing silicon nitride or diamond-like carbon onto the surface.

[0044] The resulting semi-aromatic polyamide film may be in the form of a single sheet or a film roll by winding it onto a winding roll. From the viewpoint of productivity when used for various applications, it is preferable to use it in the form of a film roll. If it is in the form of a film roll, it may be slit to the desired width.

[0045] <Water vapor barrier layer (Y)> Examples of the water vapor barrier layer (Y) constituting the laminated film of the present invention include a water vapor barrier resin layer and an inorganic thin film layer.

[0046] (Water vapor barrier resin layer) The water vapor barrier resins constituting the water vapor barrier resin layer include polyvinylidene chloride (PVDC), vinyl chloride-vinylidene chloride copolymers, vinylidene chloride-methyl acrylate copolymers, and other polyvinylidene chloride-based resins, as well as polytetrafluoroethylene (PTFE), perfluoroalkoxyalkanes (PFA), perfluoroethylenepropene copolymer (FEP), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), tetrafluoroethylene-hexafluoropropylene copolymer (TFE-HFP,FEP), tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer (TFE-HFP,VDF,THV), tetrafluoroethylene-fluoro(alkyl vinyl ether) copolymer (PFA), and 1,1,2-trichloro-1,2 Preferred adhesives include fluororesins such as chlorofluorocarbons (CFCs) including 2-trifluoroethane, hydrochlorofluorocarbons (HCFCs) such as 2,2-dichloro-1,1,1-trifluoroethane, 1,1-dichloro-1-fluoroethane, 3,3-dichloro-1,1,1,2,2-pentafluoropropane, and 1,3-dichloro-1,1,2,2,3-pentafluoropropane, perfluorocarbons (PFCs), hydrofluorocarbons (HFCs), and hydrofluoroethers (HFEs); synthetic adhesives such as styrene-butadiene, styrene-acrylic, ethylene-vinyl acetate, paraffin (wax), butadiene-methyl methacrylate, vinyl acetate-butyl acrylate, maleic anhydride copolymers, acrylic acid-methyl methacrylate copolymers, or paraffin (wax)-containing rigid adhesives; these can be used individually or in combination of two or more types.

[0047] Water vapor barrier resins may contain various agents such as leveling agents, defoaming agents, anti-wrinkle agents, pigment distributors, and ultraviolet absorbers, as well as pigments or dyes such as titanium dioxide, zinc oxide, and carbon black, as needed, provided that they do not impair the water vapor barrier properties.

[0048] Commercially available products can be suitably used as water vapor barrier resins. Examples of such commercially available products include "Fluorosurf (thermosetting type, manufactured by Fluorotechnology Inc.)", "Novec series (manufactured by 3M Corporation)", "Excevia (manufactured by Sumitomo Chemical Co., Ltd.)", "Saran Latex (manufactured by Asahi Kasei Corporation)", and "HydroBlock P-Series TR (manufactured by Honeywell Corporation)".

[0049] From the viewpoint of enhancing water vapor barrier properties, the thickness of the water vapor barrier resin layer is preferably 0.5 μm or more, more preferably 0.7 μm or more, and even more preferably 1.0 μm or more. Furthermore, the thickness of the water vapor barrier resin layer is preferably 5.0 μm or less, more preferably 4.0 μm or less, and even more preferably 3.0 μm or less. By having a water vapor barrier resin layer thickness of 5.0 μm or less, the film-forming ability is not reduced, the appearance of the film is not easily impaired, and an increase in the overall thickness of the laminated film can be suppressed. The water vapor barrier resin layer may be a single layer or a laminate of two or more layers.

[0050] The resin constituting the water vapor barrier resin layer is preferably heat-resistant from the viewpoint of reflow suitability, preferably has a melting point of 180°C or higher, more preferably 200°C or higher, and even more preferably 250°C or higher.

[0051] Methods for forming a water vapor barrier resin layer include forming it as a coating on a substrate film or forming it as a resin film. When forming a water vapor barrier resin layer by forming a coating film, a coating agent for forming a water vapor barrier resin layer is applied to a substrate film to form the coating film. Known methods can be used to form the coating film. For example, gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, dipping coating, and brush coating methods can be used. A uniform coating film can be formed using these methods. The above-mentioned coating agent for forming a water vapor barrier resin layer refers to a resin solution in which the resin constituting the water vapor barrier resin layer is dissolved in a solvent beforehand, or an aqueous dispersion in which the resin is dispersed in water.

[0052] Once the above-described coating film is formed, the coating film is dried. That is, after applying the water vapor barrier resin layer forming agent to the base film to form a coating film, the coating film is heat-treated to remove the aqueous medium, and a dense water vapor barrier resin layer is formed.

[0053] (Inorganic thin film layer) The inorganic thin film layer constituting the water vapor barrier layer is preferably composed of metals such as aluminum, silicon, titanium, zinc, zirconium, magnesium, tin, copper, and iron, or oxides, nitrides, fluorides, sulfides, etc., of these metals, or mixtures thereof. Among these, aluminum oxide, silicon oxide, magnesium oxide, zinc sulfide, titanium oxide, zirconium oxide, cerium oxide, or mixtures thereof are preferred, and from the viewpoint of water vapor barrier properties, aluminum oxide and silicon oxide are more preferred. Furthermore, the inorganic thin film layer may be a single layer or a laminate of two or more layers.

[0054] For forming the inorganic thin film layer, known methods such as physical vapor deposition methods including vacuum deposition, sputtering, and ion plating, and chemical vapor deposition methods such as CVD can be used.

[0055] In vacuum deposition, metals such as aluminum, silicon, titanium, zinc, zirconium, magnesium, and cerium, as well as compounds such as aluminum oxide, silicon oxide, magnesium oxide, zinc sulfide, titanium oxide, and zirconium oxide, and mixtures thereof, are used as deposition materials. Heating methods include resistance heating, induction heating, and electron beam heating. Furthermore, reactive deposition methods, such as introducing oxygen as a reaction gas, adding ozone, or using ion assistance, may also be employed.

[0056] From the viewpoint of enhancing water vapor barrier properties, the thickness of the inorganic thin film layer is preferably 5 nm or more, more preferably 8 nm or more, and even more preferably 10 nm or more. Furthermore, the thickness of the inorganic thin film layer is preferably 500 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less. When the thickness of the inorganic thin film layer exceeds 500 nm, the effect of improving water vapor barrier properties due to the increase in thickness decreases, while the flexibility decreases and the manufacturing cost also increases.

[0057] <Laminated film> The laminated film of the present invention is not particularly limited in its configuration as long as it has at least a base film (X) and a water vapor barrier layer (Y). However, it is preferable that the water vapor barrier layer is formed on at least one side of the semi-aromatic polyamide film, which is the base film, and more preferably on both sides of the first and second surfaces. Forming it on both sides not only improves the water vapor barrier properties but also prevents warping of the entire laminated film. Furthermore, from the standpoint of manufacturing costs, it is preferable that the water vapor barrier layer be adjacent to the base film, which is a semi-aromatic polyamide film.

[0058] The laminated film of the present invention can be manufactured, for example, by laminating a water vapor barrier layer in the process of forming a semi-aromatic polyamide film as a base film (in-line coating), by directly laminating a water vapor barrier layer after obtaining a semi-aromatic polyamide film (post-coating, post-deposition), or by laminating a semi-aromatic polyamide film with a laminated film having a water vapor barrier layer.

[0059] The laminated film of the present invention may have various functional layers in addition to the base film (X) and the water vapor barrier layer (Y). The functions of the functional layers are not particularly limited and may be general functions used in optical films, such as easy adhesion, hard coating, antistatic, anti-glare, low reflection, anti-reflective, anti-fouling, oxygen barrier, electromagnetic shielding, undercoating, ultraviolet absorption, adhesive, and hue adjustment. When used as an LED mounting substrate, adhesion to the circuit-forming metal is required, so it is preferable to have an easy adhesion function. A functional layer may be a layer having one type of function, or a layer possessing two or more functions. A functional layer may have multiple functions in a single layer, or two or more layers having different functions may be laminated together. When two or more layers are laminated, the order of lamination is set appropriately according to the function. These layers are laminated on one or both sides of the laminated film. When laminated on both sides, the thickness, function, and lamination order of the layers laminated on each side may be the same or different.

[0060] <Physical properties of laminated films> The laminated film of the present invention has a water vapor transmission rate of 5 g / (m²) at 40°C × 90% RH, as measured in accordance with JIS K7129-1. 2 d) It must be less than or equal to 3g / (m 2 d) Preferably less than 2 g / (m 2 d) is more preferably less than 1 g / (m 2 d) It is most preferable that the following conditions apply. The laminated film has a water vapor transmission rate of 5 g / m². 2d) The following conditions can be met to minimize moisture absorption and dimensional changes during each process when using the board as an LED mounting substrate. In particular, it is possible to prevent misalignment when soldering after circuit formation.

[0061] The laminated film of the present invention preferably has a moisture-absorbing elongation rate in the longitudinal direction and in the width direction of the film, measured when the humidity environment is changed from 23°C × 50%RH to 23°C × 90%RH, of 0.2% or less, more preferably 0.1% or less, and even more preferably 0.05% or less. A moisture-absorbing elongation rate of 0.2% or less allows for reduced dimensional changes due to moisture absorption during each process when used as an LED mounting substrate. In particular, it makes it possible to prevent misalignment when soldering after circuit formation.

[0062] The laminated film of the present invention preferably has a thermal shrinkage rate in the longitudinal direction and in the width direction of the film, measured under conditions of 250°C for 5 minutes, of -1.0 to 1.5%, more preferably -0.8 to 1.3%, and even more preferably -0.6 to 1.0%. A thermal shrinkage rate of 1.5% or less improves dimensional stability and provides excellent heat resistance. On the other hand, if a thermoplastic resin film has a thermal shrinkage rate exceeding 1.5%, dimensional changes become large when processed at high temperatures, which can lead to processing problems.

[0063] The laminated film of the present invention is preferably transparent from the viewpoint of visibility, and the haze of the laminated film measured in accordance with JIS K7105 is preferably 13% or less, more preferably 10% or less, and even more preferably 5% or less.

[0064] The laminated film of the present invention preferably has a loop stiffness value of 140 mN / cm or more in at least one direction of the film surface, more preferably 145 mN / cm or more, and even more preferably 150 mN / cm or more. A loop stiffness value of 140 mN / cm or more in the laminated film results in an LED mounting substrate using the laminated film exhibiting superior aesthetics.

[0065] The laminated film of the present invention preferably has a fracture rate of 400,000 or more cycles in a bending test conducted using a clamshell-type bending tester, more preferably 450,000 or more cycles, and even more preferably 500,000 or more cycles. Having a fracture rate of 400,000 or more cycles makes the laminated film suitable for use in flexible displays and other applications requiring flexibility.

[0066] <Applications of laminated films> The laminated film of the present invention has a water vapor transmission rate of 5 g / m². 2 • d) It is suitable for applications where high dimensional stability is required during processing, as it is below the specified threshold and has excellent moisture absorption dimensional stability. Specifically, this includes display applications, flexible printed circuit board applications, and solar cell substrates. In particular, because it prevents misalignment when soldering after circuit formation, it is suitable for use as an electronic substrate material such as LED mounting substrates for flexible LED displays, optical substrates such as organic EL, flexible printed wiring boards, and flexible flat cables, as well as cover-lay films for flexible printed wiring.

[0067] The copper-clad laminate obtained by laminating copper onto the laminated film of the present invention is suitably used as an LED mounting substrate, a flexible printed circuit board, and the like. The method for laminating copper onto the laminated film of the present invention is not particularly limited and includes methods such as lamination using copper foil, sputtering, and electroless plating. Examples of copper foil used in the lamination method include electrolytic copper foil and rolled copper foil. As a seed layer used in the sputtering method and electroless plating method, metals such as nickel and chromium or alloys of these metals can be used.

[0068] An example of the configuration of an LED display using the laminated film of the present invention is shown below. • LED element / circuit / (Laminated film of the present invention) • Coverlay / adhesive layer / LED element / circuit / (Laminated film of the present invention) • Hard cover layer / LED element / circuit / (Laminated film of the present invention) / Hard cover layer [Examples]

[0069] The present invention will be specifically described below with reference to examples. 1. Evaluation Method (1) Intrinsic viscosity of semi-aromatic polyamide resins The intrinsic viscosity (ηinh) of the resin was determined at concentrations of 0.05, 0.1, 0.2, and 0.4 g / dL in concentrated sulfuric acid at 30°C using the following formula, and the intrinsic viscosity [η] was defined by extrapolating this value to a concentration of 0. ηinh=[ln(t1 / t0)] / c [In the formula, ηinh represents the intrinsic viscosity (dL / g), t0 represents the solvent flow time (seconds), t1 represents the resin solution flow time (seconds), and c represents the concentration of the resin in the solution (g / dL).]

[0070] (2) Melting point and glass transition temperature of semi-aromatic polyamide resin Using a differential scanning calorimeter (PerkinElmer DSC-7), a semi-aromatic polyamide resin was heated from 20°C to 350°C at a rate of 10°C / min under a nitrogen atmosphere and held for 5 minutes (1st Scan). Then, it was cooled from 350°C to 20°C at a rate of 100°C / min and held for 5 minutes. The glass transition temperature during the subsequent reheating from 20°C to 350°C at a rate of 10°C / min (2nd Scan) was defined as the Tg of the semi-aromatic polyamide resin. Similarly, the peak top temperature of the crystal melting peak observed in the 2nd Scan was defined as Tm.

[0071] (3) Water vapor permeability of laminated film A water vapor barrier analyzer (PERMATRAN-W 3 / 33, manufactured by Mokon Corporation) was used to measure the water vapor barrier in accordance with JIS K7129-1, under conditions of 40°C and 90% relative humidity.

[0072] (4) Moisture absorption elongation of laminated film After leaving the laminated film for two days at a temperature of 23°C and a relative humidity of 50%, a test specimen (200 mm wide x 300 mm long) was cut out and marked with a gauge length of 100 mm in both the longitudinal and transverse directions. After humidification treatment for two days at a temperature of 23°C and a relative humidity of 90%, the gauge length in both the longitudinal and transverse directions was measured, and the hygroscopic elongation of the test specimen in both the longitudinal and transverse directions was determined using the following formula. Moisture-absorbing elongation rate (%) = [{Length after moisture treatment - Original length} / Original length] × 100

[0073] (5) Thermal shrinkage rate of laminated film Strip-shaped test pieces (10 mm wide x 100 mm long) were cut from the longitudinal and widthwise directions of the laminated film. Each of the obtained test pieces was heat-treated in a 250°C atmosphere for 5 minutes, and then left to stand at 23°C and 50% relative humidity for 2 hours. The longitudinal dimensions were then measured, and the thermal shrinkage rates of the longitudinal and widthwise test pieces were determined using the following formulas. Thermal shrinkage rate (%) = [{original length - length after heat treatment} / original length] × 100

[0074] (6) Haze of laminated film In accordance with JIS K7105, the haze of the laminated film was measured using a haze meter (NDH 2000) manufactured by Nippon Denshoku Co., Ltd.

[0075] (7) Flexural resistance of laminated film Test specimens cut to 30mm x 200mm were thoroughly conditioned at a temperature of 20°C and a relative humidity of 65%, and then mounted on a clamshell-type bending tester (Yuasa System Equipment Co., Ltd., DR11MR-CS-m model). For laminated films with a Y / X layer configuration, the specimens were mounted so that the water vapor barrier layer (Y) was on the inside when bent. Under the aforementioned conditions, bending tests were conducted with n=5 specimens each, under conditions of a bending radius of 1.0mm, a bending angle of 0° to 180°, and a test speed of 60r / min. At 300,000, 350,000, 400,000, and so on, test specimens were removed and visually inspected for fracture. If fracture occurred, the number of tests at that time was recorded and the test was terminated. If no fracture occurred, the bending test was continued. All tests were completed at 500,000 cycles. Test specimens that did not fracture were visually evaluated for whitening and bending marks according to the following criteria, and the lowest evaluation result was recorded. <Whitening> ○: The bent parts do not turn white. △: Transparency of the curved section has decreased. ×: The bent part turned white. <Bending marks> ○: No bending marks remain. △: A crease has formed due to bending. ×: Bending marks remained.

[0076] (8) Appearance of the LED mounting board A copper-clad laminate was obtained by laminating copper onto the surface of a laminated film using a sputtering method with a nickel-chromium alloy seed layer. For laminated films with a Y / X layer configuration, copper was laminated on the water vapor barrier layer (Y) side. An etching mask patterned with the shape of a wiring pattern was formed on the surface of the copper foil layer of the obtained copper-clad laminate. Subsequently, the copper foil uncovered by the etching mask was removed using an immersion solution, followed by the removal of the etching mask using an alkaline stripping solution. Finally, an LED element was soldered onto the resulting copper foil with the wiring pattern shape to create a simple LED mounting board. The warping and solder misalignment of the fabricated LED mounting boards were visually evaluated according to the following criteria. When used as an LED mounting board, a "○" or "△" rating is preferable for both evaluations, with "○" being the most preferable. <curve> ○: No warping or lifting has occurred. △: The edges are raised. ×: Warping has occurred. <Solder misalignment> ○: No solder misalignment occurred. △: Solder misalignment has occurred, but power is still flowing to the LED element. ×: A soldering misalignment has occurred, preventing power from flowing to the LED element.

[0077] 2. Raw materials (1) Semi-aromatic polyamide resin Semi-aromatic polyamide resin A: The product used was manufactured using the following method. 3289 parts by mass of terephthalic acid (TA), 2533 parts by mass of 1,9-nonanediamine (NDA), 633 parts by mass of 2-methyl-1,8-octanediamine (MODA), 48.9 parts by mass of benzoic acid (BA), 6.5 parts by mass of sodium hypophosphate monohydrate (0.1% by mass relative to the total of the four polyamide raw materials), and 2200 parts by mass of distilled water were placed in a reaction vessel and purged with nitrogen. The molar ratio of these raw materials (TA / BA / NDA / MODA) was 99 / 2 / 80 / 20. After stirring the contents of the reaction kettle at 100 °C for 30 minutes, the internal temperature was raised to 210 °C over 2 hours. At this time, the pressure inside the reaction kettle increased to 2.12 MPa (22 kg / cm 2 ). After continuing the reaction for 1 hour as it was, the temperature was raised to 230 °C, and then the temperature was maintained at 230 °C for 2 hours while gradually removing steam and reacting while maintaining the pressure at 2.12 MPa (22 kg / cm 2 ). Next, the pressure was reduced to 0.98 MPa (10 kg / cm 2 ) over 30 minutes, and the reaction was continued for another 1 hour to obtain a prepolymer. This was dried under reduced pressure at 100 °C for 12 hours and then pulverized to a size of 2 mm or less. Next, the pulverized prepolymer was subjected to solid-phase polymerization at a temperature of 230 °C and a pressure of 13.3 Pa (0.1 mmHg) for 10 hours to obtain a polymer. This was supplied to a twin-screw extruder (TEX44C manufactured by Japan Steel Works, Ltd.), melt-kneaded, extruded, cooled, and cut under the condition of a cylinder temperature of 320 °C to produce pellets of semi-aromatic polyamide resin A. The semi-aromatic polyamide resin A had a melting point of 290 °C, a glass transition temperature of 125 °C, and an intrinsic viscosity of 1.17 dL / g.

[0078] Semi-aromatic polyamide resin B: The one produced by the following method was used. 489 parts by mass of terephthalic acid (TA), 507 parts by mass of 1,10-decanediamine (DDA), 2.8 parts by mass of benzoic acid (BA), 1.0 part by mass of sodium hypophosphite monohydrate (0.1% by mass based on the total of the three polyamide raw materials), and 1000 parts by mass of distilled water were placed in a reaction kettle and purged with nitrogen. The molar ratio of these raw materials (TA / BA / DDA) was 99 / 2 / 100. The contents of the reaction kettle were stirred at 80 °C for 0.5 hours at 28 revolutions per minute and then heated to 230 °C. Then, it was heated at 230 °C for 3 hours. Then, it was cooled and the reaction product was taken out. After pulverizing the reaction product, it was heated in a dryer under a nitrogen stream at 220°C for 5 hours to undergo solid-phase polymerization and obtain a polymer. This polymer was fed into a twin-screw extruder (TEX44C, manufactured by Japan Steel Works, Ltd.), melt-kneaded and extruded under cylinder temperature conditions of 320°C, cooled, and cut to produce pellets of semi-aromatic polyamide resin B. Semi-aromatic polyamide resin B had a melting point of 316°C, a glass transition temperature of 150°C, and an intrinsic viscosity of 1.24 dL / g.

[0079] (2) Fine particles Master tips (M1) and (M2) containing 2% by mass of silica, prepared by the method described below, were used. • Master chip (M1): 98 parts by mass of semi-aromatic polyamide resin A and 2 parts by mass of silica (Tosoh Silica Co., Ltd., NIPGEL AZ-204, average particle size 1.7 μm) were melt-kneaded together. • Master chip (M2): 98 parts by mass of semi-aromatic polyamide resin B and 2 parts by mass of silica (Tosoh Silica Co., Ltd., NIPGEL AZ-204, average particle size 1.7 μm) were melt-kneaded together.

[0080] (3) Hindered phenol-based heat stabilizers GA:3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (Sumitomo Chemical Co., Ltd., Sumirizer GA-80, thermal decomposition temperature 392℃)

[0081] (4) Water vapor barrier resin The following resins were used to form the water vapor barrier resin layer. • Resin C latex: PVDC latex, Saran latex L536B (manufactured by Asahi Kasei Corporation) • Coating agent for resin D: Silane fluoride coating agent, Novec 1720 (manufactured by 3M) • Resin E film: PCTFE film, HydroBlock P600TR (manufactured by Honeywell) • Coating agent for resin H: Urethane-based coating agent, Takelac WS-4000 (manufactured by Mitsui Chemicals, Inc.)

[0082] Example 1 Semi-aromatic polyamide resin A, GA, and master tip (M1) were mixed so that the total weight of semi-aromatic polyamide resin A was 100 parts by mass, GA was 0.2 parts by mass, and silica was 0.1 parts by mass. This mixture was introduced into a 65 mm single-screw extruder set to a cylinder temperature of 320°C and melted. It was then extruded into a sheet through a T-die set to 320°C, and cooled by electrostatic adhesion onto a cooling roll set to a surface temperature of 40°C, yielding a substantially unoriented, unstretched film with a thickness of 650 μm. Next, the unstretched film was guided to a tenter-type simultaneous biaxial stretcher while both ends were held with clips, and simultaneous biaxial stretching was performed. The stretching conditions were a preheating section temperature of 155°C, a stretching section temperature of 150°C, a stretching strain rate of 3200% / min in the longitudinal and width directions, and a stretching ratio of 3.0x and 3.3x in the longitudinal and width directions, respectively. After stretching, a heat setting treatment was performed at 280°C for 5 seconds, followed by a relaxation treatment with a relaxation rate of 1% in the longitudinal direction and 3% in the width direction to obtain a semi-aromatic polyamide film with a thickness of 75 μm. A latex of resin C (solid content concentration 50% by mass) was applied to the first surface of the obtained semi-aromatic polyamide film by gravure roll coating, and the film was dried for 30 seconds using an infrared irradiation machine at a temperature of 140°C to evaporate the moisture in the latex and form a water vapor barrier layer with a thickness of 2 μm. Subsequently, the latex of resin C was applied to the second surface of the semi-aromatic polyamide film using the same method to obtain a laminated film with a water vapor barrier layer (Y) of 2 μm / base film (X) of 75 μm / water vapor barrier layer (Y) of 2 μm.

[0083] Examples 2-9 A laminated film was obtained in the same manner as in Example 1, except that the type of semi-aromatic polyamide resin used, the stretching ratio, the stretching method, the relaxation ratio, the thickness, and the thickness of the water vapor barrier layer were changed as shown in Table 1.

[0084] Example 10 A latex of resin C was applied to the first surface of a semi-aromatic polyamide film obtained in the same manner as in Example 1 by gravure roll coating, and the film was dried for 30 seconds using an infrared irradiation machine at a temperature of 140°C to evaporate the moisture in the latex and form a water vapor barrier layer with a thickness of 2 μm, resulting in a laminated film with a water vapor barrier layer (Y) of 2 μm and a base film (X) of 75 μm.

[0085] Example 11 A laminated film was obtained in the same manner as in Example 10, except that the thickness of the water vapor barrier layer (Y) was set to 4 μm.

[0086] Example 12 Semi-aromatic polyamide resin A, GA, and master tip (M1) were mixed so that the total weight of semi-aromatic polyamide resin A was 100 parts by mass, GA was 0.2 parts by mass, and silica was 0.1 parts by mass. This mixture was introduced into a 65 mm single-screw extruder set to a cylinder temperature of 320°C and melted. It was then extruded into a sheet through a T-die set to 320°C, and cooled by electrostatic adhesion onto a cooling roll set to a surface temperature of 40°C, yielding a substantially unoriented, unstretched film with a thickness of 650 μm. Next, the latex of resin C was applied to the first surface of the unstretched film using the air knife coating method, and then subjected to an infrared irradiation treatment at a temperature of 110°C for 30 seconds to evaporate and dry the moisture in the latex. Subsequently, the latex of resin C was applied to the second surface of the semi-aromatic polyamide film using the same method and dried. The unstretched film, coated with this latex and with its ends held by clips to allow the moisture in the latex to dry, was guided to a tenter-type simultaneous biaxial stretching machine and subjected to simultaneous biaxial stretching. The stretching conditions were: preheating section temperature of 155°C, stretching section temperature of 150°C, stretching strain rate of 3200% / min in the longitudinal and width directions, and stretching ratio of 3.0x and 3.3x in the longitudinal and width directions, respectively. After stretching, a heat setting treatment was performed at 280°C for 5 seconds, followed by a relaxation treatment with a relaxation rate of 1% in the longitudinal direction and 3% in the width direction, to obtain a laminated film with a water vapor barrier layer (Y) of 2 μm / base film (X) of 75 μm / water vapor barrier layer (Y) of 2 μm.

[0087] Example 13 A coating agent of resin D (solid content concentration 0.1% by mass) was applied to the first surface of a semi-aromatic polyamide film obtained in the same manner as in Example 1 by gravure roll coating, and the film was dried using an infrared irradiation machine at a temperature of 100°C for 25 minutes to evaporate the moisture in the coating film and form a water vapor barrier layer with a thickness of 2 μm. Subsequently, the coating agent of resin D was applied to the second surface of the semi-aromatic polyamide film using the same method to obtain a laminated film with a water vapor barrier layer (Y) of 2 μm / base film (X) of 75 μm / water vapor barrier layer (Y) of 2 μm.

[0088] Example 14 A semi-aromatic polyamide film obtained in the same manner as in Example 1 was treated with 20 W·min / m² on both sides. 2 Corona discharge treatment was performed at the specified treatment intensity. Subsequently, a two-component polyurethane adhesive (I) (TM-K55 / CAT-10L, manufactured by Toyo Morton Co., Ltd.) was applied to the first surface of the semi-aromatic polyamide film at a rate of 5 g / m². 2 The adhesive was applied in this manner and dried at 80°C for 10 seconds. A film of resin E was then bonded to the adhesive-coated surface. The same method was used to bond a film of resin E to the second surface of the semi-aromatic polyamide film, obtaining a laminated film with a water vapor barrier layer (Y) of 15 μm, an adhesive layer (I) of 0.5 μm, a base film (X) of 75 μm, an adhesive layer (I) of 0.5 μm, and a water vapor barrier layer (Y) of 15 μm.

[0089] Example 15 A semi-aromatic polyamide film obtained in the same manner as in Example 1 was treated with 20 W·min / m² on both sides. 2 Corona discharge treatment was performed at a treatment intensity of 10. Afterward, the semi-aromatic polyamide film was set in the unwinding device of a continuous vacuum deposition machine and wound up by running it through a cooling metal drum. At this time, the continuous vacuum deposition machine was set to 10 -4The pressure was reduced to below Torr, and 99.99% pure metallic aluminum was loaded into an alumina crucible from the bottom of the cooling drum. The metallic aluminum was heated and evaporated, and oxygen was supplied into the vapor to cause an oxidation reaction, which allowed it to adhere and deposit onto the first surface of the film, forming an inorganic thin film layer (F) with a thickness of 0.03 μm of aluminum oxide. Subsequently, an aluminum oxide film was formed on the second surface of the semi-aromatic polyamide film using the same method, obtaining a laminated film with a water vapor barrier layer (Y) of 0.03 μm, a base film (X) of 75 μm, and a water vapor barrier layer (Y) of 0.03 μm.

[0090] Example 16 A laminated film with an inorganic thin film layer (G) was obtained in the same manner as in Example 15, except that aluminum was used as the metal for vapor deposition.

[0091] Comparative Example 1 A semi-aromatic polyamide film was obtained in the same manner as in Example 1.

[0092] Comparative Example 2 A coating agent of resin H (solid content concentration 20% by mass) was applied to the first surface of a semi-aromatic polyamide film obtained in the same manner as in Example 1 by gravure roll coating, and the film was dried for 30 seconds using an infrared irradiation machine at a temperature of 100°C to evaporate the moisture in the coating film and form a resin layer with a thickness of 2 μm. Subsequently, the coating agent of resin H was applied to the second surface of the semi-aromatic polyamide film using the same method to obtain a laminated film with a resin layer (Y) of 2 μm / base film (X) of 75 μm / resin layer (Y) of 2 μm.

[0093] Table 1 shows the composition of the laminated film, the manufacturing conditions of the base film (X) and the water vapor barrier layer (Y), and the physical properties of the laminated film.

[0094] [Table 1]

[0095] The laminated films of Examples 1-16 have a water vapor transmission rate of 5 g / (m²). 2•d) The material was as follows, exhibiting excellent moisture absorption and dimensional stability, and no solder misalignment occurred when processing the LED mounting board. The films and laminated films of Comparative Examples 1 and 2 had a water vapor transmission rate of 5 g / (m²). 2 It exceeded (d), resulting in poor moisture absorption and dimensional stability, causing solder misalignment.

Claims

1. A laminated film having at least a base film (X) and a water vapor barrier layer (Y), wherein the base film (X) is a semi-aromatic polyamide film, and the water vapor transmission rate of the laminated film at 40°C × 90% RH measured in accordance with JIS K7129-1 is 5 g / (m²). ２ d) The following: A laminated film characterized in that, when the humidity environment is changed from 23°C × 50% RH to 23°C × 90% RH, the moisture-absorbing elongation in the longitudinal direction and the moisture-absorbing elongation in the width direction of the laminated film are both 0.2% or less.

2. The laminated film according to claim 1, characterized in that it has a water vapor barrier layer (Y) on the first surface side of the base film (X), and also has a water vapor barrier layer (Y) on the second surface side of the base film (X).

3. The laminated film according to claim 1 or 2, characterized in that the semi-aromatic polyamide film is biaxially oriented.

4. The laminated film according to any one of claims 1 to 3, characterized in that a base film (X) and a water vapor barrier layer (Y) are adjacent to each other.

5. A copper-clad laminate comprising a laminated film having at least a base film (X) and a water vapor barrier layer (Y), wherein the base film (X) is a semi-aromatic polyamide film, and the water vapor transmission rate of the laminated film at 40°C × 90% RH, measured in accordance with JIS K7129-1, is 5 g / (m²·d) or less.

6. An LED mounting substrate using a laminated film having at least a base film (X) and a water vapor barrier layer (Y), wherein the base film (X) is a semi-aromatic polyamide film, and the water vapor transmission rate of the laminated film at 40°C × 90% RH, measured in accordance with JIS K7129-1, is 5 g / (m²·d) or less.

7. An LED display using the LED mounting substrate described in claim 6.

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