Electrolyte membrane reinforcing member, fuel cell, and water electrolysis device

Abstract

The present invention provides a biaxially oriented polyarylene sulfide film that can suppress warping during processing and exhibits excellent pressure uniformity when multiple layers are stacked and pressed. [Solution] A biaxially oriented polyarylene sulfide film comprising polyarylene sulfide resin as the main component, wherein the thickness variation in the film width direction is 0.5% or more and 10.0% or less over a 300 mm width centered on the center of the film width direction, the orientation angle from the longitudinal direction of the film is greater than -35° and less than 35°, or -90° or more and less than -55°, or greater than 55° and 90° or less, and the difference between the maximum and minimum values ​​of the orientation angle is 0.5° or more and 20.0° or less.

Description

Technical Field

[0001] The present invention relates to a biaxially oriented polyarylene sulfide film, a roll of biaxially oriented polyarylene sulfide film, an electrolyte membrane reinforcing member, a fuel cell, a water electrolysis device, a metallized film, a current collector foil, a secondary battery, a film capacitor, an electrical insulating paper for a motor, and a motor.

Background Art

[0002] With the increasing functionality and precision of electrical and electronic devices, battery materials, mechanical parts, and automotive parts, the required quality of the components used has become stricter. For example, the required quality for fuel cells, water electrolysis devices, base films for capacitors, and base films for current collector foils is strict. These components often require processing steps such as laminating other materials to the base film and heat treatment.

[0003] Polyarylene sulfide has properties such as excellent heat resistance, hydrolysis resistance, flame retardancy, rigidity, chemical resistance, electrical insulation, and low hygroscopicity, and is particularly suitable for use in electrical and electronic devices, battery materials, mechanical parts, and automotive parts. In recent years, solid polymer fuel cells and water electrolysis devices developed from the perspective of carbon neutrality are formed by stacking multiple single cells and combining them as a stack. And these have a reinforcing material that is hermetically joined so as not to suppress wrinkles and deformation of the electrolyte membrane during processing, mechanically reinforce the peripheral portion of the electrolyte membrane, and prevent fuel gas and oxygen gas from leaking from the interface with the electrolyte membrane. Further, as the reinforcing material, a material having the required mechanical strength, hydrolysis resistance, etc. even at the operating temperature is preferable, and a polyarylene sulfide film represented by polyphenylene sulfide (hereinafter sometimes abbreviated as PPS) is being advanced in application to the electrolyte membrane reinforcing material by taking advantage of its high hydrolysis resistance.

[0004] To date, technologies for reinforcing members of solid electrolyte membranes with reduced metal element content in PPS resin have been disclosed (Patent Document 1). Technologies for improving the quality of PPS films by residence time and oxygen concentration have also been disclosed (Patent Document 2). In addition, technologies for reducing thickness variation in the longitudinal direction by alloying with other thermoplastic resins have been disclosed (Patent Document 3). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-219136 [Patent Document 2] Japanese Patent Publication No. 2021-088174 [Patent Document 3] Japanese Patent Publication No. 2022-151606 [Overview of the project] [Problems that the invention aims to solve]

[0006] Due to the unique molecular structure of its highly durable resin, PPS film is prone to thickness variations and orientation irregularities during biaxial stretching. Furthermore, this film is susceptible to deformation and warping during lamination and processing, which can lead to handling problems and misalignment due to thickness variations when stacking hundreds of layers.

[0007] The technologies described in Patent Documents 1 and 2 are insufficient to improve thickness variations and orientation irregularities in PPS, and have the problem of gaps forming when many layers are stacked. Furthermore, the technology described in Patent Document 3 reduces thickness variations in the longitudinal direction, but is insufficient to improve thickness variations and orientation irregularities in the width direction, and has the problem of gaps forming when many layers are stacked.

[0008] The objective of this invention is to solve the above-mentioned problems. Specifically, it is to provide a biaxially oriented polyarylene sulfide film that can suppress warping during processing and exhibits excellent pressure uniformity when multiple layers are stacked and pressed. [Means for solving the problem]

[0009] The configuration of the present invention is as follows. (1) A biaxially oriented polyarylene sulfide film comprising polyarylene sulfide resin as the main component, wherein the thickness variation in the film width direction is 0.5% or more and 10.0% or less over a 300 mm width centered on the center of the film width direction, the orientation angle from the longitudinal direction of the film is greater than -35° and less than 35°, -90° or more and less than -55°, or greater than 55° and 90° or less, and the difference between the maximum and minimum values ​​of the orientation angle is 0.5° or more and 20.0° or less. (Method for measuring the orientation angle from the longitudinal direction of the film) The evaluation was performed using a microwave transmission type molecular orientation analyzer MOA-6015 (manufactured by Oji Instruments Co., Ltd.) at a frequency of 15 GHz. The film was cut into strips of 300 mm in width and 30 mm in length, and these cut film samples were further cut into 30 mm strips in width, resulting in 10 film samples of 30 mm in width and 30 mm in length. The orientation angle was determined with the film's length direction as the 0° direction of the measuring instrument (the range of the measured orientation angle is -90° to 90°). The average of the orientation angles at the 10 measurement points in the width direction was taken as the orientation angle from the film's length direction, and the difference between the maximum and minimum orientation angles at the 10 measurement points in the width direction was also calculated. (2) The biaxially oriented polyarylene sulfide film according to (1), wherein the orientation angle is greater than -30° and less than 30°, or -90° or more and less than -60°, or greater than 60° and less than or equal to 90°. (3) A biaxially oriented polyarylene sulfide film according to (1) or (2), wherein the thickness variation in the film width direction is 0.5% or more and 6.0% or less in a 300 mm width centered on the center of the film width direction. (4) A biaxially oriented polyarylene sulfide film according to any one of (1) to (3), wherein the modulus of elasticity measured at 130°C is 1.0 GPa or more in the longitudinal and width directions. (5) A biaxially oriented polyarylene sulfide film according to any one of (1) to (4), wherein the mean center surface roughness SRa of at least one surface is 10 nm or more and 100 nm or less. (6) A biaxially oriented polyarylene sulfide film according to any of (1) to (5), wherein the calcium ion concentration is 10 ppm by mass or less. (Method for measuring calcium ion concentration) The film is cut with ceramic scissors to a weight of 4g and used as the analytical sample. After washing the surface with ultrapure water, it is heated and extracted for 2 hours in 100 mL of pre-boiled 5% by mass nitric acid solution. The extracted solution is qualitatively analyzed by ICP mass spectrometry (ICP-MS) to determine the calcium ion concentration per unit mass of the sample. ICP-MS analyzer: Agilent 8800 manufactured by Agilent Technologies (7) A biaxially oriented polyarylene sulfide film according to any of (1) to (6), wherein, in the differential molecular weight distribution curve measured by gel permeation chromatography, the value on the vertical axis (dw / dLogM) when the value on the horizontal axis (LogM) is 5.2 is 0.10 or more and 0.60 or less. (Method for creating differential molecular weight distribution curves) A differential molecular weight distribution curve is prepared according to JIS K7252 (2016). Specifically, 5 mL of 1-chloronaphthalene (1-CN) is added to 5 mg of the sample, and the mixture is gently stirred at 210-220°C for 20 minutes, visually confirming dissolution. Then, the mixture is filtered using a 0.5 μm filter. A GPC curve is obtained by measurement under the conditions shown below. The obtained GPC curve is transformed using a molecular weight calibration curve created by approximating the logarithm of the molecular weight of polystyrene with a cubic equation of the elution time, and the weight fraction is calculated normalized so that the peak area is 1. Note that the molecular weight is a relative value based on polystyrene, and a differential molecular weight distribution curve is created by plotting the logarithm of molecular weight M on the x-axis and the weight fraction (dw / dLogM) on the y-axis. From the obtained differential molecular weight distribution curve, the value on the y-axis (dw / dLogM) when the value on the x-axis (LogM) is 5.2 is read. Equipment: High temperature GPC equipment (equipment No. GPC-H-2, PL-GPC220 manufactured by Polymer Laboratories) Detector: Differential refractive index detector (RI) Data interval: every 0.5 seconds Column: Shodex UT-G (Guard Column) PLgel 10m MIXED-B-LS (2 rolls) (8.0mm x 30cm, manufactured by Polymer Laboratories) Solvent: 1-Chloronaphthalene Flow rate: 0.7mL / min Column temperature: 210℃ Injection volume: 0.200mL Standard sample: Monodisperse polystyrene manufactured by Tosoh Corporation (8) A biaxially oriented polyarylene sulfide film according to any of (1) to (7), wherein, in the differential molecular weight distribution curve measured by gel permeation chromatography, the value on the vertical axis (dw / dLogM) when the value on the horizontal axis (LogM) is 4.0 is 0.10 or more and 0.40 or less. (9) A biaxially oriented polyarylene sulfide film according to any of (1) to (8), wherein, in the differential molecular weight distribution curve measured by gel permeation chromatography, the value on the vertical axis (dw / dLogM) when the value on the horizontal axis (LogM) is 5.5 is 0.01 or more and 0.25 or less. (10) A biaxially oriented polyarylene sulfide film according to any of (1) to (9), wherein the resonance parameter (Q value) is 4600 or more and 5200 or less. (11) A biaxially oriented polyarylene sulfide film according to any of (1) to (10), wherein the minute endothermic peak temperature (T-meta) determined by differential scanning calorimetry (DSC) is 200°C or higher (melting point - 20°C) or lower. (12) A biaxially oriented polyarylene sulfide film roll obtained by winding a biaxially oriented polyarylene sulfide film as described in any of (1) to (11). (13) An electrolyte membrane reinforcing member having a biaxially oriented polyarylene sulfide film as described in any of (1) to (11). (14) An electrolyte membrane reinforcement member having a biaxially oriented polyarylene sulfide film that satisfies conditions (a) and (b). (a) The calcium ion concentration is 10 ppm by mass or less. (b) In the differential molecular weight distribution curve measured by gel permeation chromatography, the value on the vertical axis (dw / dLogM) is between 0.15 and 0.60 when the value on the horizontal axis (LogM) is 5.2. (15) The electrolyte membrane reinforcing member according to (14), wherein in the differential molecular weight distribution curve measured by gel permeation chromatography, the value on the vertical axis (dw / dLogM) when the value on the horizontal axis (LogM) is 4.0 is 0.10 or more and 0.40 or less. (16) The electrolyte membrane reinforcing member according to (14) or (15), wherein, in the differential molecular weight distribution curve measured by gel permeation chromatography, the value on the vertical axis (dw / dLogM) when the value on the horizontal axis (LogM) is 5.5 is 0.01 or more and 0.25 or less. (17) A rectangular frame-shaped electrolyte membrane reinforcing member having an opening, wherein at least one film layer constituting the electrolyte membrane reinforcing member satisfies conditions (A) and (B). (A) The orientation angle is more than -35° and less than 35°, -90° or more and less than -55°, or more than 55° and less than or equal to 90°. (B) The difference between the maximum value and the minimum value of the orientation angle is 0.5° or more and 20° or less. (Method for measuring the orientation angle of the electrolyte membrane reinforcing member) Using a microwave transmission type molecular orientation meter MOA-6015 (manufactured by Oji Scientific Instruments Co., Ltd.), evaluate at a frequency of 15 GHz. Set any one of the outer peripheral side directions of the rectangular frame-shaped electrolyte membrane reinforcing member as the 0° direction of the measuring device, and cut the four sides of the frame-shaped part of the film layer along the outer periphery into a size of 30 mm × 30 mm. Obtain the orientation angle of the film layer taken out from the electrolyte membrane reinforcing member from the cut sample (the range of the measured orientation angle is -90° to 90°). Take the average value of the orientation angles of the obtained film layer frame-shaped part as the orientation angle of the measured layer, and also obtain the difference between the maximum value and the minimum value of the orientation angles of the film layer frame-shaped part. (18) The electrolyte membrane reinforcing member according to (17), wherein the thickness variation when measuring the film layer satisfying the conditions (A) and (B) at intervals of 10 mm is 0.5% or more and 10.0% or less. (19) The electrolyte membrane reinforcing member according to (17) or (18), wherein the tanδ peak temperature by dynamic viscoelasticity measurement of the film layer satisfying the conditions (A) and (B) is 120°C or more and 160°C or less. (20) The electrolyte membrane reinforcing member according to any one of (17) to (19), wherein the film layer satisfying the conditions (A) and (B) contains a polyarylene sulfide resin as a main constituent. (21) A fuel cell having the electrolyte membrane reinforcing member according to any one of (13) to (20). (22) A water electrolysis device having the electrolyte membrane reinforcing member according to any one of (13) to (20). (23) A metallized film formed by providing a metal layer on at least one side of the biaxially oriented polyarylene sulfide film according to any one of (1) to (11). A current collector foil formed by providing a metal layer on at least one side of the biaxially oriented polyarylene sulfide film according to any one of (1) to (11). A secondary battery using the current collector foil according to (25). A film capacitor using the metallized film according to (23). Electric insulation paper for a motor using the biaxially oriented polyarylene sulfide film according to any one of (1) to (11). A motor using the electric insulation paper for a motor according to (27).

Advantages of the Invention

[0010] According to the present invention, it is possible to provide a biaxially oriented polyarylene sulfide film that can suppress warping during processing and has excellent pressure uniformity when stacked and pressed in large numbers. The biaxially oriented polyarylene sulfide film in the present invention can be suitably used as an automotive, various parts of electric and electronic materials, circuit base materials, heat-resistant tape base materials, films for printing toner stirrers, and release films. In particular, it can be suitably used as an electrolyte membrane reinforcing member for fuel cells and water electrolysis devices with strict requirements for flatness, for film capacitors, and for current collector foil base materials.

Brief Description of the Drawings

[0011] [Figure 1] It is a top view of an electrolyte membrane reinforcing member having an opening according to an embodiment of the present invention. [Figure 2] It is a schematic diagram of a slant overhead view showing a configuration example of an electrolyte membrane reinforced by a film and an adhesive layer.

Modes for Carrying Out the Invention

[0012] A preferred embodiment of the present invention is a biaxially oriented polyarylene sulfide film containing polyarylene sulfide resin as the main component, wherein the thickness variation in the film width direction is 0.5% or more and 10.0% or less over a 300 mm width centered on the center of the film width direction, the orientation angle from the longitudinal direction of the film is greater than -35° and less than 35°, greater than -90° and less than -55°, or greater than 55° and 90° or less, and the difference between the maximum and minimum values ​​of the orientation angle is 0.5° or more and 20.0° or less. According to this embodiment, a biaxially oriented polyarylene sulfide film with small thickness variation and orientation unevenness and excellent processability can be provided.

[0013] In the present invention, the biaxially oriented polyarylene sulfide film is preferably a film that is biaxially oriented and whose main component is a polyarylene sulfide resin (hereinafter sometimes abbreviated as PAS resin). This film can be obtained by melt-molding a resin composition containing PAS resin as the main component to form a sheet, then by biaxial stretching and heat-setting.

[0014] In this invention, "containing PAS resin as a main component" means containing 90% by mass or more of PAS resin. More preferably, it contains 95% by mass or more of PAS resin. A PAS resin content of 90% by mass or more allows for the expression of excellent heat resistance, hydrolysis resistance, chemical resistance, electrical properties, and mechanical properties.

[0015] The biaxially oriented polyarylene sulfide film in the present invention may contain thermoplastic resins other than PAS resin, as long as they are within a range of less than 10% by mass, which does not impede the effects of the present invention. For example, it may contain various polymers such as polyamide, polyetherimide, polyethersulfone, polysulfone, polyphenylene ether, polyphenylsulfone, polyester, polyarylate, polyamideimide, polycarbonate, polyolefin, polyetheretherketone, fluororesin, and blends containing at least one of these polymers. If components other than PAS resin are present in excess, delamination, cracking, voids, etc. may occur at the interface with the PAS resin, accelerating degradation and potentially resulting in poor durability and barrier properties. Furthermore, in the present invention, recycled PAS resin raw materials may be used, as long as they do not impede the effects of the invention.

[0016] The PAS resin used in this invention is a copolymer having repeating units of -(Ar-S)-. Examples of Ar (arylene group) include the units represented by the following formulas (A) to (K).

[0017] [ka]

[0018] (R1 and R2 are substituents selected from hydrogen, alkyl groups, alkoxy groups, and halogen groups, and R1 and R2 may be the same or different.)

[0019] As the repeating unit, the p-arylene sulfide unit represented by the above formula (A) is preferred, and from the viewpoint of film properties and economics, the p-phenylene sulfide unit is particularly preferred. Typical PAS resins having these repeating units include polyphenylene sulfide, polysulfone, polyethersulfone, polyphenylene sulfide sulfone, and polyphenylene sulfide ketone.

[0020] The PAS resin used in this invention is preferably composed of p-phenylene sulfide units, represented by the following structural formula, as the main constituent units, in an amount of 80.0 mol% to 99.9 mol% of the total repeating units. More preferably, it is 90.0 mol% to 99.9 mol%, and most preferably 95.0 mol% to 99.9 mol%. By using the above composition, high crystallinity and degree of orientation can be maintained, and excellent heat resistance and chemical resistance can be achieved.

[0021] [ka]

[0022] Furthermore, copolymerization with copolymerization units is also possible in a range of 0.01 mol% to 20.00 mol% of the repeating units.

[0023] Preferred copolymerization units include the following:

[0024] [ka]

[0025] [ka]

[0026] [ka]

[0027] Here, X represents alkylene, CO, and SO2 units.

[0028] [ka]

[0029] [ka]

[0030] Here, R represents an alkyl, nitro, phenylene, or alkoxy group.

[0031] There are no particular limitations on the type of copolymer, but a random copolymer is preferred.

[0032] In the present invention, the polyarylene sulfide film is preferably a biaxially oriented film. By making the polyarylene sulfide film a biaxially oriented film, it is possible to improve mechanical strength, flatness, productivity, and thickness variation. When used as an automotive component, battery component, various electrical and electronic material component, and industrial packaging material, it is preferable that the film has been biaxially stretched in order to improve its properties. As examples of biaxial stretching methods, as shown in the manufacturing method described later, examples include sequential biaxial stretching (a stretching method that combines stretching in one direction at a time, such as stretching in the longitudinal direction followed by stretching in the width direction), simultaneous biaxial stretching (a method that stretches in the longitudinal and width directions simultaneously), or a method that combines these. Here, "the polyarylene sulfide film is a biaxially oriented film" means that the resonance parameter (Q value) of the polyarylene sulfide film, measured using a molecular orientation meter (Oji Keisokuki Co., Ltd., MOA-6015), is 4300 or higher.

[0033] The biaxially oriented polyarylene sulfide film of the present invention preferably has a resonance parameter (Q value) of 4600 or more and 5200 or less. In the present invention, the Q value is measured using a molecular orientation meter (Oji Instruments Co., Ltd., MOA-6015) and is the average value of 10 measurements of the parameter (Q value) that indicates the sharpness of the resonance of the biaxially oriented polyarylene sulfide film. The detailed measurement method is as described in the examples. The Q value increases as the orientation of molecular chains within the film increases. A resonance parameter (Q value) within the above range indicates that the molecular chains are sufficiently oriented, which is preferable because the thickness variation is better due to the arrangement of molecular chains. If the resonance parameter (Q value) is less than 4600, the orientation is not sufficient, the thickness variation is large, and there is a risk that the flatness and processability will be poor when used as a fuel cell or water electrolysis device. A resonance parameter (Q value) exceeding 5200 indicates that the molecular chains are extremely oriented, which reduces the tensile elongation of the film and may cause breakage due to processing tension during coating and die-cutting processes, potentially leading to a decrease in yield. The resonance parameter (Q value) is more preferably 4700 or higher, even more preferably 4800 or higher, and particularly preferably 4900 or higher. The resonance parameter (Q value) is more preferably 5000 or lower. In the film formation conditions described later, the resonance parameter (Q value) tends to increase with higher stretching ratios, and tends to decrease with higher stretching temperatures.

[0034] A preferred embodiment of the present invention is a biaxially oriented polyarylene sulfide film roll obtained by winding a biaxially oriented polyarylene sulfide film. In the present invention, the biaxially oriented polyarylene sulfide film roll preferably has a film width of 300 mm or more. It may be an intermediate product roll wound immediately after the film is manufactured, or it may be a product roll obtained by slitting an intermediate product roll.

[0035] The biaxially oriented polyarylene sulfide film in the present invention may be a single film or a composite film. Examples of composite films include laminated films of two or more layers. For example, the biaxially oriented polyarylene sulfide film in the present invention may be a two-layer laminated film consisting of layer A / layer B, or a three-layer laminated film consisting of layer A / layer B / layer A, with the biaxially oriented polyarylene sulfide film in the surface layer (layer A). When used as a reinforcing member for fuel cells and water electrolysis devices, for capacitors, for current collector foil, or for motor electrical insulating paper, it is preferable that all layers contain polyarylene sulfide resin as the main component from the viewpoint of hydrolysis resistance and mechanical properties.

[0036] In a preferred embodiment of the biaxially oriented polyarylene sulfide film of the present invention, the thickness variation in the film width direction is 0.5% to 10.0% over a 300 mm width centered on the center of the film width direction. By keeping the film thickness variation within the above range, it is possible to suppress displacement due to thickness variation when used as an electrolyte membrane reinforcing member and stacked. In other words, by adopting the above embodiment, it is possible to achieve excellent pressure uniformity when many films are stacked and pressed. By keeping the film width direction thickness variation at 10.0% or less, it is possible to prevent deterioration of flatness and poor stackability as an electrolyte membrane reinforcing member when this film is laminated with other materials or heat processed. Furthermore, if the film width direction thickness variation is less than 0.5%, in the film manufacturing process, it is possible to reduce the thickness variation in the film width direction by increasing the longitudinal stretching ratio in the film manufacturing process described later and then performing transverse stretching, thereby homogenizing stress propagation during transverse stretching. However, this requires extremely high stretching ratios, which may worsen film manufacturing performance. The thickness variation in the film width direction is more preferably 1.0% or more. More preferably 9.0% or less, even more preferably 8.0% or less, and most preferably 6.0% or less. In general, biaxially oriented polyarylene sulfide films have small interactions between molecular chains due to their resin properties, and stress propagation is difficult during stretching, making it difficult to reduce thickness variation. However, under the film formation conditions described later, when the stretching ratio is high and the resonance parameter (Q value) of the film is high, the thickness variation in the film width direction tends to decrease, and when the heat-fixing temperature is low, the thickness variation tends to decrease. Regarding the molecular weight distribution of the raw materials, when there are many low molecular weight components, the stretchability during film formation increases, and the thickness variation tends to decrease. Based on these trends, the thickness variation in the present invention can be adjusted to the range described above.

[0037] In a preferred embodiment of the biaxially oriented polyarylene sulfide film of the present invention, the thickness variation in the width direction center over a length of 300 mm of the film is 0.5% to 10.0%. By setting the thickness variation in the longitudinal direction of the film within the above range, it is possible to use it as an electrolyte membrane reinforcing member in the same way as the film width direction and suppress misalignment due to thickness variation when stacked. By setting the thickness variation in the longitudinal direction of the film to 10.0% or less, it is possible to prevent deterioration of flatness or poor stackability as an electrolyte membrane reinforcing member when this film is laminated with other materials or heat processed. Furthermore, by setting the thickness variation in the longitudinal direction of the film to 0.5% or more, it is not necessary to extremely increase the longitudinal stretching ratio in the film manufacturing process described later, resulting in favorable film manufacturing properties. The thickness variation in the longitudinal direction of the film is more preferably 1.0% or more. The thickness variation in the longitudinal direction of the film is more preferably 9.0% or less, even more preferably 8.0% or less, and most preferably 6.0% or less. In the film-forming conditions described later, a higher longitudinal stretching ratio tends to reduce the thickness variation in the longitudinal direction of the film, and a lower heat-fixing temperature also tends to reduce the thickness variation. Regarding the molecular weight distribution of the raw materials, an increase in high molecular weight components tends to lead to more efficient stress propagation during stretching during film formation, resulting in a reduction in thickness variation in the film thickness direction. Based on these trends, the thickness variation in the present invention can be adjusted to the range described above.

[0038] In this invention, the width direction refers to the direction along the shorter side of the film roll, and the longitudinal direction of the film refers to the direction perpendicular to the width direction, i.e., the direction along the longer side of the film roll. On the other hand, if the longitudinal direction cannot be determined when the film is cut into a sheet, one direction is set to 0°, and the elastic modulus is measured by changing the direction in 10° increments from -90° to 90° within the film surface, and the direction with the largest elastic modulus is taken as the longitudinal direction. Next, lines are drawn in the longitudinal direction and in the direction perpendicular to it so as to pass through the center of gravity of a sample cut into a 150mm x 150mm square, and the orientation angles between the ends (4 locations) on these lines and the center of gravity are evaluated, and the direction in which the difference between the maximum and minimum orientation angles at both ends and the center of the line is larger is taken as the width direction.

[0039] In a preferred embodiment of the biaxially oriented polyarylene sulfide film of the present invention, the orientation angle from the longitudinal direction of the film is greater than -35° and less than 35°, -90° or more and less than -55°, or greater than 55° and 90° or less, with a width of 300 mm centered on the center in the width direction of the film. When the orientation angle from the longitudinal direction of the film is within the above range, it indicates that the orientation deviation is small, which reduces warping and deformation during lamination with other materials and improves the stackability as an electrolyte membrane reinforcing member. When the orientation angle from the longitudinal direction of the film is greater than -55° and less than -35°, or greater than 35° and less than 55°, the deviation of the orientation axis becomes large, which may cause warping and deformation during lamination with other materials. The orientation angle from the longitudinal direction of the film is more preferably greater than -30° and less than 30°, -90° or more and less than -55°, or greater than 55° and 90° or less, even more preferably greater than -30° and less than 30°, or -90° or more and less than -60°, or greater than 60° and 90° or less, particularly preferably -25° or more and 25° or less, or -90° or more and -65° or less, or 65° or more and 90° or less, especially preferably -20° or more and 20° or less, or -90° or more and -70° or less, or 70° or more and 90° or less, and most preferably -20° or more and 20° or less. The orientation angle from the longitudinal direction tends to approach 0° when the longitudinal stretching ratio is high and when the transverse stretching ratio is high, among the film formation conditions described later. Also, when the heat setting temperature is low, the orientation angle from the longitudinal direction tends to approach -90°, 0°, or 90°.

[0040] In a preferred embodiment of the biaxially oriented polyarylene sulfide film of the present invention, the difference between the maximum and minimum orientation angles over a 300 mm width centered on the center of the film in the width direction is 0.5° or more and 20.0° or less. When the difference between the maximum and minimum orientation angles is within the above range, the uniformity of orientation is small, which reduces warping when heat processing is performed for lamination with electrolyte membrane reinforcement members, etc., and makes stacking easier. In order to produce a film in which the difference between the maximum and minimum orientation angles is less than 0.5°, the film production process can be carried out by stretching only and not performing heat fixing, or by performing heat fixing off-line, thereby eliminating bowing of the film and obtaining a film with small orientation uniformity. However, this may worsen film production performance and may cause significant deformation and warping during heat processing. If the difference between the maximum and minimum orientation angles exceeds 20.0°, there is a risk that warping during lamination will increase and flatness will decrease.

[0041] The difference between the maximum and minimum orientation angles is more preferably 3.0° or more, and even more preferably 5.0° or more. The difference is more preferably 18.0° or less, and even more preferably 15.0° or less. In general, biaxially oriented polyarylene sulfide films have high thermal responsiveness due to their resin properties and are susceptible to bowing during heat-setting and relaxation treatments, making it difficult to reduce the difference in orientation angles. However, under the film-forming conditions described later, the difference tends to increase when the longitudinal stretching ratio is high, and when the heat-setting temperature is high. Also, the difference tends to decrease by reducing the amount of relaxation per relaxation treatment. Furthermore, the difference tends to decrease when the high molecular weight component in the molecular weight distribution is increased. Also, the difference tends to decrease when the widthwise stretching is performed twice. Based on these trends, the difference in orientation angles in the present invention can be adjusted to the range described above.

[0042] In the present invention, the biaxially oriented polyarylene sulfide film preferably has an elastic modulus of 1.0 GPa or higher in both the longitudinal and width directions, as measured at 130°C. An elastic modulus within this range is preferable because it maintains rigidity during the heat processing of the electrolyte membrane, suppresses deformation, and maintains flatness. More preferably, the elastic modulus measured at 130°C is 1.2 GPa or higher, and even more preferably 1.4 GPa or higher, in both the longitudinal and width directions. While there is no particular upper limit to the elastic modulus measured at 130°C, it is preferably 4.0 GPa or lower, and more preferably 3.5 GPa or lower, in both directions. Within this range, the orientation does not become too high, allowing for control of the film's elastic modulus and thermal shrinkage rate. Regarding the elastic modulus measured at 130°C, under the film formation conditions described later, a high longitudinal stretching ratio tends to result in a higher elastic modulus measured at 130°C in both the longitudinal and width directions, a high transverse stretching ratio tends to result in a higher elastic modulus measured at 130°C in the width direction, and a low heat-fixing temperature tends to result in a higher elastic modulus measured at 130°C.

[0043] The weight-average molecular weight of the biaxially oriented polyarylene sulfide film in the present invention is preferably 45,000 or more, more preferably 50,000 or more, and even more preferably 60,000 or more. A weight-average molecular weight of 45,000 or more is preferable because it tends to provide sufficient mechanical strength as a biaxially oriented film and reduces thickness variation. There is no particular upper limit to the weight-average molecular weight, but a preferred range is 150,000 or less, more preferably 120,000 or less, and even more preferably 100,000 or less. By keeping it within this range, the tensile elongation and durability of the biaxially oriented film can be controlled. The weight-average molecular weight is a value measured using a gel permeation chromatograph (hereinafter sometimes abbreviated as GPC) equipped with a differential refractive index detector. More specifically, the values ​​were calculated using a GPC with a column temperature of 210°C and a detector temperature of 210°C, with 1-chloronaphthalene as the eluent, at a flow rate of 1.0 mL / min, using a 1-chloronaphthalene solution with a PAS concentration of 0.1% by mass, and polystyrene as the standard substance.

[0044] In the present invention, the biaxially oriented polyarylene sulfide film preferably has a peak in the differential molecular weight distribution curve measured by the gel permeation chromatography method described later, where the logarithm of the molecular weight M (LogM) is in the range of 4.0 to 6.0. Within this range, viscosity during melt extrusion can be ensured, and the tensile elongation and durability of the biaxially oriented film can be controlled.

[0045] In the present invention, the biaxially oriented polyarylene sulfide film preferably has a differential molecular weight distribution curve measured by the gel permeation chromatography method described later, where the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) is 0.10 or more and 0.60 or less when the logarithm of molecular weight M (LogM) is 5.2. Within this range, it indicates that a large number of high molecular weight molecular chains are present, resulting in a greater number of components that act as stress propagation points during stretching in the width direction, thereby reducing orientation variation. If the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) is less than 0.10 when the logarithm of molecular weight M (LogM) is 5.2, there is a small number of components that act as stress propagation points during stretching in the width direction (TD), which may lead to greater thickness variation. When the logarithm of molecular weight M, LogM, is 5.2, if the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) is greater than 0.60, the viscosity during melt extrusion will increase due to the presence of many high molecular weight components, potentially leading to large variations in thickness during extrusion molding and increased thickness variability in the biaxially oriented film. From this viewpoint, it is more preferable that the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) when the logarithm of molecular weight M, LogM, is 5.2, be 0.15 or higher, and even more preferable that it be 0.20 or higher. It is even more preferable that the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) when the logarithm of molecular weight M, LogM, is 5.2, be 0.55 or lower.

[0046] In the present invention, the biaxially oriented polyarylene sulfide film preferably has a differential molecular weight distribution curve measured by the gel permeation chromatography method described later, where the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) when the logarithm of molecular weight M (LogM) is 4.0 is 0.10 or more and 0.40 or less. The value on the vertical axis of the differential molecular weight distribution curve indicates the content of low molecular weight components, and it is preferable that this value is within the above range because it allows for improved transportability during processing when used as an electrolyte membrane reinforcing member, while reducing the low molecular weight components, thus enabling suitable use. If it is less than 0.10, when heat and tension are applied during transport such as coating, there are fewer low molecular weight components to disperse stress, which may lead to deformation due to stress concentration and deterioration of transportability. If the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) when the logarithm of molecular weight M (LogM) is 4.0 is greater than 0.40, the heat resistance of the biaxially oriented polyarylene sulfide may decrease. From the above viewpoint, when the logarithm LogM of molecular weight M is 4.0, the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) is more preferably 0.15 or higher, and even more preferably 0.20 or higher. When the logarithm LogM of molecular weight M is 4.0, the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) is more preferably 0.35 or lower, and more preferably 0.30 or lower.

[0047] In the present invention, the biaxially oriented polyarylene sulfide film preferably has a differential molecular weight distribution curve measured by the gel permeation chromatography method described later, where the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) when the logarithm of molecular weight M (LogM) is 5.5 is 0.01 or more and 0.25 or less. This range indicates the presence of long molecular chain components, where polymer entanglement becomes a stress propagation point during stretching, allowing for uniform stretching and thus reducing orientation and thickness variations. Furthermore, the presence of long molecular chain components results in lower molecular chain fluidity and increased rigidity, which can suppress deformation during aging processes after adhesive coating or during heating and pressurizing processes, potentially improving processability. If the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) when the logarithm of molecular weight M (LogM) is 5.5 is less than 0.01, there are fewer entangled components that act as stress propagation points during stretching, potentially leading to greater thickness variations or the occurrence of wrinkles and warping due to deformation during processing. When the logarithm of molecular weight M, LogM, is 5.5, if the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) is greater than 0.25, the entanglement component of molecular chains increases, leading to higher viscosity during melt extrusion, which may result in larger thickness variations during extrusion molding and greater thickness variability in the biaxially oriented film. From this viewpoint, it is more preferable that the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) when the logarithm of molecular weight M, LogM, is 5.5, be 0.02 or higher, and even more preferable that it be 0.05 or higher. It is even more preferable that the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) when the logarithm of molecular weight M, LogM, is 5.5, be 0.20 or lower.

[0048] In the present invention, the biaxially oriented polyarylene sulfide film preferably has a center plane average roughness SRa of 10 nm or more and 100 nm or less on at least one of the film surfaces. Center plane average roughness SRa is a parameter of three-dimensional surface roughness and means the average roughness at the center plane when the surface roughness curve is approximated by a sine curve. Center plane average roughness SRa is an extension of the center line average roughness (Ra), a two-dimensional roughness parameter described in JIS B0601-1994, to three dimensions, and is obtained by dividing the volume of the portion enclosed by the surface shape curve and the center plane by the measured area. When the center plane is the XY plane, the vertical direction is the Z axis, and the measured surface shape curve is f(x, y), it is defined by the following formula (i). Here, Lx is the measurement length in the X direction, and Ly is the measurement length in the Y direction.

[0049]

number

[0050] By setting the SRa within the above range, a film with excellent run-through performance can be obtained. If the SRa on the film surface is less than 10 nm, the surface is smooth, which may increase friction during transport and reduce run-through performance. If the SRa on the film surface exceeds 100 nm, the surface becomes uneven and slippery, which may cause slippage during stacking. The SRa is more preferably between 20 nm and 50 nm. Adding particles or other resins contained in the film, as described later, tends to increase surface roughness. The SRa should be evaluated by the method described later.

[0051] To control the surface roughness of the film, one method is to add inert particles within a range that does not hinder the effects of the present invention. Examples of inert particles include inorganic fillers such as silica, alumina, calcium carbonate, barium carbonate, barium titanate, barium sulfate, calcium silicate, magnesium oxide, titanium oxide, and zinc oxide, as well as particles of organic polymer compounds that do not melt at 300°C (e.g., cross-linked polystyrene). By adding inert particles, the slipperiness of the film can be improved during the film stretching process, suppressing the occurrence of wrinkles when the film runs between rolls, and maintaining the surface irregularities of the film even when the temperature of heat setting following transverse stretching is increased, thereby suppressing surface scratches and improving running performance.

[0052] In the present invention, the biaxially oriented polyarylene sulfide film preferably has a calcium ion content of 10 ppm by mass or less when extracted with boiling nitric acid. If the calcium ion content is greater than 10 ppm by mass, when used as a reinforcing member in a fuel cell or water electrolysis device, calcium elements may leach out under the high temperature, high humidity, and strong acidity conditions inside the fuel cell cell, potentially causing catalyst contamination and gas diffusion layer contamination in the fuel cell, and reducing the power generation of the fuel cell. The calcium ion content is more preferably 5 ppm by mass or less, and even more preferably 3 ppm by mass or less. The calcium ion content can be controlled to be within the above range by using a polyarylene sulfide resin with few impurities, by ensuring appropriate drying and extrusion conditions, and by performing a total design that includes slippery particles to improve the quality used in the film. The calcium ion content is evaluated by the method described later.

[0053] From the viewpoint of further improving thermal stability, the biaxially oriented polyarylene sulfide film of the present invention preferably has a minute endothermic peak temperature (T-meta) determined by differential scanning calorimetry (DSC) of 200°C or higher (melting point - 20°C or lower). In the present invention, the minute endothermic peak temperature (T-meta) indicates that the film has undergone thermal history. When T-meta is within the above range, the bowing of the film during the film-forming process can be controlled, and a film with excellent flatness and processability can be obtained. If T-meta is less than 200°C, the thermal history is low, and there is a risk that the flatness and processability will deteriorate due to the heat during processing. If T-meta exceeds (Tm - 20°C), there is a risk that the bowing of the film will increase, and the processability will deteriorate. T-meta is more preferably 210°C or higher and 260°C or lower, even more preferably 210°C or higher and 250°C or lower, and particularly preferably 215°C or higher and 240°C or lower. T-meta can be controlled by a heat-fixing temperature. T-meta varies depending on the film deposition machine and deposition rate, but generally, T-meta increases with higher thermal fixation temperatures. Furthermore, the melting point (Tm) is preferably between 275°C and 290°C, and more preferably between 283°C and 290°C.

[0054] In the present invention, there are no particular limitations on the thickness of the biaxially oriented polyarylene sulfide film, but from the viewpoint of film-forming properties, the film thickness is preferably 0.5 μm to 300 μm. For electrolyte membrane reinforcing members and electrical insulating paper for motors, from the viewpoint of handling properties, 10 to 150 μm is more preferable, 20 to 125 μm is even more preferable, and 35 to 120 μm is most preferable. Furthermore, for applications such as film capacitors and battery current collector foil substrates for lithium-ion secondary batteries, a thickness of 0.5 μm to 15 μm is preferable from the viewpoint of balancing durability and thin film thickness, with a thickness of 9.0 μm or less, and even more preferably 6.0 μm or less. The film thickness can be measured with a known micrometer, and details will be described later.

[0055] The present invention will describe a method for producing a biaxially oriented polyarylene sulfide film using polyphenylene sulfide resin (hereinafter sometimes abbreviated as PPS resin) as the polyarylene sulfide resin, but the present invention is not limited to this example.

[0056] Sodium sulfide and p-dichlorobenzene are combined and reacted under high temperature and pressure in an amide-based polar solvent such as N-methyl-2-pyrrolidone (NMP). Copolymer components such as m-dichlorobenzene and trihalobenzene can be included as needed. Potassium hydroxide or alkali metal carboxylic acid salts are added as polymerization modifiers and the polymerization reaction is carried out at 200-290°C. The molecular weight of the resulting PPS resin can be controlled by known methods (e.g., International Publication No. 2007 / 108384). After polymerization, the polymer is cooled, filtered as an aqueous slurry, and a wet granular polymer is obtained. This granular polymer is washed by adding an amide-based polar solvent and stirring at a temperature of 30-100°C, washed several times with deionized water at 30-80°C, washed several times with an aqueous solution of a metal salt such as an aqueous solution of calcium acetate, and then dried to obtain a granular polymer of polyphenylene sulfide (PPS granules). This granular polymer is fed into a vented extruder and melt-extruded into strands. After cooling with water at 25°C, it is cut to produce chips, which are then made into PPS pellets.

[0057] A masterbatch is prepared by mixing the PPS granules obtained above with inorganic particles and / or other thermoplastic resins in any proportion as the polyarylene sulfide resin. The concentration of inorganic particles and / or other thermoplastic resins in the masterbatch is preferably 1% to 25% by mass, and more preferably 5% to 15% by mass. If the concentration is higher than 25% by mass, the dispersibility will deteriorate and the dispersion diameter may increase. If it is less than 1% by mass, the amount of masterbatch used will increase when diluted and used, which may be undesirable from a cost standpoint. In the present invention, a method for preparing the masterbatch is preferably one that uses a device that applies shear stress, such as a twin-screw extruder. In this case, it is preferable to knead the mixture in the kneading section so that the resin temperature range is (melting point of PAS resin + 5°C) or higher and (melting point of PAS resin + 80°C) or lower, more preferably (melting point of PAS resin + 10°C) or higher and (melting point of PAS resin + 80°C) or lower, and even more preferably (melting point of PAS resin + 15°C) or higher and (melting point of PAS resin + 70°C) or lower. Furthermore, it is preferable to set the screw rotation speed to a range of 100 rpm to 1500 rpm. By setting the resin temperature and screw rotation speed within a preferred range, the dispersion diameter of the dispersed phase can be controlled.

[0058] In the present invention, the method for controlling the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) when the logarithm LogM of molecular weight M is 4.0, 5.2, and 5.5 can be a method of controlling the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) during polymerization, a method of blending multiple types of PPS pellets with different molecular weights and feeding them into an extruder to control the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM), or a method combining these. From the viewpoint of controlling the viscosity of extrusion during film formation, blending multiple types of different PPS pellets is preferably exemplified.

[0059] In this invention, first, PPS chips dried under reduced pressure at 180°C for 3 hours as needed and a masterbatch are mixed in a predetermined ratio and supplied to a full-flight single-screw extruder with the molten section set to 300-350°C. After passing through a filter, the mixture is then extruded from a T-die type die. The die temperature is preferably 300-350°C, more preferably 305-325°C, and most preferably 305-315°C. It is preferable to rapidly cool and solidify the mixture while applying an electrostatic charge to a cooling drum with a surface temperature of 20-70°C to obtain an unstretched film that is substantially unoriented.

[0060] Next, the unstretched film obtained above is biaxially stretched using a sequential biaxial stretcher or a simultaneous biaxial stretcher at a temperature range above the glass transition temperature (Tg) of the polyarylene sulfide resin, and then subjected to one or more stages of heat setting at a temperature in the range of 150 to 280°C to obtain a biaxially oriented film. As for the stretching method, sequential biaxial stretching (a stretching method that combines stretching in one direction at a time, such as stretching in the longitudinal direction followed by stretching in the width direction), simultaneous biaxial stretching (a method that stretches in the longitudinal and width directions simultaneously), or a method that combines these can be used. Here, sequential biaxial stretching, in which stretching is performed first in the longitudinal direction and then in the width direction, is given as an example.

[0061] The unstretched film is heated with a group of heated rolls and stretched in the longitudinal direction (MD) by 3.4 times or more, more preferably 3.6 times or more, and even more preferably 3.8 times or more in one or two or more stages (MD stretching). By setting the MD stretching to the above range and arranging the molecular chains in the longitudinal direction, stress propagation points during widthwise stretching are effectively formed, and the thickness in the widthwise direction in this invention can be controlled. There is no particular upper limit to the MD stretching ratio, but a preferred range is 5.0 times or less, more preferably 4.8 times or less, and even more preferably 4.5 times or less. If this range is exceeded, the orientation in one direction becomes too pronounced during MD stretching, which may lead to deterioration of film formation due to film breakage during transverse stretching, and may result in large variations in the orientation angle in the widthwise direction during heat fixing treatment. The stretching temperature is in the range of Tg to Tcc (temperature of crystallization during heating), preferably (Tg + 5°C) to (Tcc - 5°C). After that, it is cooled with a group of cooling rolls at 20 to 50°C. Following stretching in the MD direction, stretching in the width direction (TD direction) is generally performed using a tenter. The ends of the film are gripped with clips and guided to the tenter for stretching in the width direction (TD stretching). The stretching temperature is preferably in the range of (Tg (glass transition temperature of polyarylene sulfide) + 5°C) to (Tg + 40°C), and more preferably in the range of (Tg + 7°C) to (Tg + 30°C). In the case of PPS, it is 95°C to 135°C, and more preferably 97°C to 125°C. The stretching ratio in the width direction is preferably 3.0 times or more and 4.5 times or less from the viewpoint of obtaining a film with good flatness. The lower limit of the stretching ratio in the width direction is more preferably 3.1 times or more, and even more preferably 3.2 times or more. The upper limit of the stretching ratio in the width direction is more preferably 4.2 times or less, and even more preferably 4.0 times or less.

[0062] Next, stretching is performed again in the TD direction (TD stretching 2). The stretching temperature for TD stretching 2 is 200°C to the melting point (Tm) - 30°C, preferably 215°C to Tm - 40°C. The stretching ratio for TD stretching 2 is preferably 1.01 times or more and 2.00 times or less, more preferably 1.05 times or more and 1.50 times or less. By performing TD stretching 2 at the above stretching temperature and stretching ratio, the orientation variation in the width direction can be made uniform by stretching at a high temperature in the width direction of the film.

[0063] Next, the stretched film is subjected to a heat-fixing process under tension. The heat-fixing process is performed either by heating at the same temperature from beginning to end in the heat-fixing zone, or by a single-stage heat-fixing process or by heating at different temperatures in the first and second halves of the heat-fixing zone. The heat-fixing temperature is preferably 200°C or higher (melting point - 20°C) or lower, more preferably 210°C or higher and 250°C or lower, and even more preferably 215°C or higher and 240°C or lower, from the viewpoint of having the thermal stability necessary for processing while suppressing variations in the orientation angle in the film width direction. If the heat-fixing temperature is below 200°C, there is a risk of wrinkles occurring due to deformation during processing as an electrolyte membrane reinforcing member. If the heat-fixing temperature exceeds the melting point - 20°C, the variation in the orientation angle will increase, and there is a risk of deterioration in flatness during processing.

[0064] Next, it is preferable to perform a relaxation treatment in the longitudinal and / or widthwise directions while the heat-fixed biaxially oriented film is held by clips. In the present invention, it is preferable to perform the widthwise relaxation treatment in two or more stages at different temperatures. Performing the relaxation treatment in two or more stages at different temperatures makes it possible to suppress abrupt strain relaxation and allows for good control of thickness variations and orientation angle irregularities in the TD direction, making this a preferred embodiment. The relaxation rate is the value of the difference between the width between clips before treatment and the width after treatment, based on the width between clips before treatment. For example, a relaxation rate of 2% means that if the width before treatment is 100 mm, 2% (2 mm) is relaxed, resulting in a width of 98 mm after treatment. The relaxation rate of the preceding relaxation treatment (hereinafter sometimes abbreviated as Rx1) is preferably 1.0 to 10.0%, and more preferably 3.0 to 7.0%. Furthermore, the temperature when performing the relaxation treatment (Rx1) is preferably (heat-fixing temperature - 20°C) or higher and (heat-fixing temperature + 10°C) or lower. The subsequent relaxation treatment (hereinafter sometimes abbreviated as Rx2) preferably has a relaxation rate of 0.1 to 5%, and more preferably 1 to 4%. The temperature during the subsequent relaxation treatment (Rx2) is preferably above (heat fixing temperature - 80°C) and below (heat fixing temperature - 10°C).

[0065] Subsequently, the film is cooled to a temperature preferably 35°C or lower, more preferably 25°C or lower, after which the film edges are removed and the film is wound onto a core. Furthermore, from the viewpoint of improving thermal dimensional stability, the wound PPS film may be transported under tension at a constant temperature and subjected to annealing. In a preferred embodiment, the annealing temperature is 130°C to 190°C. If the temperature exceeds 190°C, excessive shrinkage strain is removed during the annealing process, resulting in a state where many molecular chains are relaxed. When temperature and tension are applied to the film again in subsequent processes, this can lead to dimensional changes during processing and may worsen the control of processing dimensions. If the temperature is below 130°C, the removal of distortion in the molecular structure by the annealing process may be incomplete, which may worsen the control of processing dimensions. A more preferred annealing temperature is 140°C to 180°C. The transport tension during annealing is preferably 0.5 MPa to 3.0 MPa, more preferably 0.8 MPa to 2.0 MPa. The annealing time is preferably 1 to 200 seconds, more preferably 10 to 100 seconds, and even more preferably 10 to 50 seconds. The biaxially oriented polyarylene sulfide film of the present invention can be obtained by annealing while conveying at a speed of 1 to 100 m / min.

[0066] In the present invention, the polyarylene sulfide film or the film roll thereof may be subjected to any processing as necessary, such as molding, surface treatment, lamination, coating, printing, embossing, and etching. The biaxially oriented polyarylene sulfide film of the present invention has excellent durability and can be suitably used as a component for various parts of automobiles, electrical and electronic materials, circuit boards, heat-resistant tape substrates, toner agitator films for printing, and release films. In particular, it can be suitably used as an electrolyte membrane reinforcing member for fuel cells and water electrolysis devices, as well as for film capacitors and current collector foil substrates, where durability and dimensional stability are required.

[0067] A preferred embodiment of the present invention is an electrolyte membrane reinforcing member having a biaxially oriented polyarylene sulfide film that satisfies the following (a) and (b). (a) The amount of calcium ions in the polyarylene sulfide film is 10 ppm by mass or less. (b) In the differential molecular weight distribution curve of the polyarylene sulfide film layer measured by gel permeation chromatography, the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) is between 0.15 and 0.60 when the logarithm LogM of the molecular weight M on the horizontal axis is 5.2.

[0068] By adopting this embodiment, it is possible to control orientation unevenness and thickness variations and provide an electrolyte membrane reinforcing member with excellent processability.

[0069] In the present invention, the electrolyte membrane reinforcing member having a polyarylene sulfide film is a polyarylene sulfide film and / or laminate having, for example, an opening punched out in a frame-like or picture-frame shape corresponding to the outer peripheral shape of the solid electrolyte membrane shown in Figure 1, wherein the opening has a shape corresponding to the outer peripheral shape of the solid electrolyte membrane. The electrolyte membrane reinforcing member may be a laminate containing at least one polyarylene sulfide film layer and an adhesive layer for adhesion to the electrolyte membrane. The configuration of the laminate may include a polyarylene sulfide film layer only, a two-layer configuration of a polyarylene sulfide film layer / adhesive layer, a polyarylene sulfide film layer / adhesive layer / polyarylene sulfide film layer, or a three-layer configuration of an adhesive layer / polyarylene sulfide film layer / adhesive layer.

[0070] It is preferable that the amount of calcium ions in the polyarylene sulfide film layer of the electrolyte membrane reinforcement member having the polyarylene sulfide film of the present invention, when extracted with boiling nitric acid, is 10 ppm by mass or less. If the amount of calcium ions is greater than 10 ppm by mass, when used as a reinforcement member for fuel cells or water electrolysis devices, calcium elements may leach out under the high temperature, high humidity, and strong acid conditions inside the fuel cell cell, potentially causing catalyst contamination and gas diffusion layer contamination in the fuel cell, and reducing the power generation of the fuel cell. More preferably, the amount of calcium ions is 5 ppm by mass or less, and even more preferably 3 ppm by mass or less. The amount of calcium ions can be controlled to be within the above range by using a polyarylene sulfide resin with few impurities, by making the drying and extrusion conditions appropriate, and by performing a total design that includes slippery particles to improve the quality used in the film. The amount of calcium ions is evaluated by the method described later.

[0071] In the electrolyte membrane reinforcement member having a polyarylene sulfide film of the present invention, the polyarylene sulfide film layer preferably has a peak in the differential molecular weight distribution curve measured by the gel permeation chromatography method described later, in the range of Logarithm of molecular weight M (LogM) from 4.0 to 6.0, and the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) when Logarithm of molecular weight M (LogM) is 5.2 is preferably 0.15 or more and 0.60 or less. If it is within the above range, a large number of high molecular weight molecular chains are contained, molecular motion is suppressed, and when used as an electrolyte membrane reinforcement member, deformation due to temperature and pressure is small, and thickness and orientation unevenness can be reduced. If the value on the vertical axis of the differential molecular weight distribution curve when Logarithm of molecular weight M (LogM) is 5.2 is less than 0.15, the film becomes more susceptible to deformation due to the temperature and pressure in the usage environment, and as a result, there is a risk of large variations in thickness. When the logarithm of molecular weight M (LogM) is 5.2, if the value on the vertical axis of the differential molecular weight distribution curve exceeds 0.60, the viscosity during melt extrusion increases due to the presence of many high molecular weight components, which may lead to large variations in the thickness of the electrolyte membrane reinforcement member during molding and thus large variations in the thickness of the electrolyte membrane reinforcement member. From the above viewpoint, it is more preferable that the value on the vertical axis of the differential molecular weight distribution curve when the logarithm of molecular weight M (LogM) is 5.2 is 0.20 or higher. It is even more preferable that the value on the vertical axis of the differential molecular weight distribution curve when the logarithm of molecular weight M (LogM) is 5.2 is 0.55 or lower.

[0072] In the electrolyte membrane reinforcement member having a polyarylene sulfide film in the present invention, it is preferable that the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) when the logarithm of molecular weight M (LogM) is 4.0 is 0.10 or more and 0.40 or less, as measured by the gel permeation chromatography method described later. The value on the vertical axis of the differential molecular weight distribution curve indicates the content of low molecular weight components, and if this value is within the above range, it is possible to reduce the low molecular weight components while reducing thickness fluctuations and eluted components in the usage environment when used as an electrolyte membrane reinforcement member. If it is less than 0.10, the amount of low molecular weight components will be too small, which may lead to plastic deformation due to temperature and pressure in the usage environment and worsen thickness variation. If the value on the vertical axis of the differential molecular weight distribution curve when the logarithm of molecular weight M (LogM) is 4.0 is greater than 0.40, the amount of low molecular weight components will be too large, which may lead to poor durability due to temperature and pressure in the usage environment. From the above viewpoint, when the logarithm of molecular weight M, LogM, is 4.0, the value on the vertical axis of the differential molecular weight distribution curve is more preferably 0.15 or higher, and even more preferably 0.20 or higher. When the logarithm of molecular weight M, LogM, is 4.0, the value on the vertical axis of the differential molecular weight distribution curve is more preferably 0.35 or lower, and more preferably 0.30 or lower.

[0073] In the electrolyte membrane reinforcement member having a polyarylene sulfide film in the present invention, it is preferable that the value on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) when the logarithm of molecular weight M (LogM) is 5.5 is 0.01 or more and 0.25 or less, as measured by the gel permeation chromatography method described later. If it is within the above range, a large number of high molecular weight molecular chains are contained, molecular motion is suppressed, and when used as an electrolyte membrane reinforcement member, deformation due to temperature and pressure is small, and thickness variations and orientation irregularities can be reduced. If the value on the vertical axis of the differential molecular weight distribution curve when the logarithm of molecular weight M (LogM) is 5.5 is less than 0.01, there is a risk that deformation will occur due to temperature and pressure in the usage environment, and thickness variations will gradually increase. When the logarithm of molecular weight M (LogM) is 5.5, if the value on the vertical axis of the differential molecular weight distribution curve is greater than 0.25, there is a high amount of high molecular weight components, which increases the viscosity during melt extrusion and may lead to large variations in thickness during molding into electrolyte membrane reinforcement members, resulting in greater thickness variability in the electrolyte membrane reinforcement members. From the above viewpoint, it is more preferable that the value on the vertical axis of the differential molecular weight distribution curve when the logarithm of molecular weight M (LogM) is 5.5 is 0.02 or greater, and even more preferable that it is 0.05 or greater. It is even more preferable that the value on the vertical axis of the differential molecular weight distribution curve when the logarithm of molecular weight M (LogM) is 5.5 is 0.22 or less.

[0074] A preferred embodiment of the present invention is a rectangular frame-shaped electrolyte membrane reinforcing member having an opening, wherein at least one film layer constituting the electrolyte membrane reinforcing member satisfies the following conditions (A) and (B). (A) When the orientation angle is measured using the measurement method described later, the orientation angle is greater than -35° but less than 35°, greater than or equal to -90° but less than -55°, or greater than 55° but less than or equal to 90°. (B) When the orientation angle is measured using the measurement method described later, the difference between the maximum and minimum values ​​of the orientation angle is 0.5° or more and 20° or less.

[0075] The method for measuring the orientation angle will be described later.

[0076] By adopting this embodiment, it is possible to provide an electrolyte membrane reinforcing member with minimal orientation unevenness and excellent processability.

[0077] In the present invention, the electrolyte membrane reinforcing member is a film and / or laminate having a frame-shaped or picture-frame-shaped opening punched out to correspond to the outer peripheral shape of the solid electrolyte membrane shown in Figure 1, for example, and the opening having a shape corresponding to the outer peripheral shape of the solid electrolyte membrane. The electrolyte membrane reinforcing member may be a laminate containing at least one film layer and an adhesive layer for adhesion to the electrolyte membrane. The configuration of the laminate may include a film layer only, a two-layer configuration of a film layer / adhesive layer, a film layer / adhesive layer / film layer, or a three-layer configuration of adhesive layer / film layer / adhesive layer.

[0078] In the present invention, the film layer of the electrolyte membrane reinforcing member preferably contains polyester resin or polyarylene sulfide resin as its main component, from the viewpoint of chemical resistance and heat and humidity resistance. More preferably, the film layer of the electrolyte membrane reinforcing member in the present invention is made of a polyarylene sulfide film containing polyarylene sulfide resin as its main component. Most preferably, it is made of a polyphenylene sulfide film containing polyphenylene sulfide resin as its main component, as it has mechanical strength, hydrolysis resistance, etc.

[0079] In the present invention, the rectangular frame-shaped electrolyte membrane reinforcing member preferably has at least one side measuring 150 mm or more. By setting it within this range, the area of ​​the electrolyte membrane can be increased, which can improve the operating efficiency when used in fuel cells or water electrolysis devices.

[0080] In the present invention, from the viewpoint of suitably bonding with the electrolyte membrane and separator, the area of ​​the opening of the electrolyte membrane reinforcing member is preferably 30% to 90% of the outer circumference shape of the fuel cell laminate.

[0081] In the present invention, when measuring at least one film layer of the electrolyte membrane reinforcing member, with the outer peripheral direction of the electrolyte membrane reinforcing member set as the 0° direction of the measuring instrument, and the film layer frame-shaped portion is cut along the outer circumference into 30mm x 30mm sections on all four sides of the frame, it is preferable that the orientation angle is greater than -35° and less than 35°, greater than -90° and less than -55°, or greater than 55° and less than or equal to 90°. When the orientation angle is within the above range, the deviation of orientation is reduced, which reduces warping and deformation during lamination with other materials and improves the stackability of the electrolyte membrane reinforcing member. When the orientation angle is greater than -55° and less than or equal to -35°, or greater than or equal to 35° and less than or equal to 55°, the deviation of the orientation axis is large, which may cause warping and deformation during lamination with other materials. The orientation angle is preferably greater than -30° and less than 30° or greater than -90° and less than -60°, or greater than 60° and 90° or less, more preferably greater than -25° and 25° or greater than -90° and less than -65° or greater than 65° and 90° or less, even more preferably greater than -20° and 20° or greater than -90° and less than -70° or greater than 70° and 90° or less, and most preferably greater than -20° and 20° or less.

[0082] In the electrolyte membrane reinforcing member of the present invention, it is preferable that the difference between the maximum and minimum orientation angles in at least one film layer is 0.5° or more and 20° or less. When the difference between the maximum and minimum orientation angles is within the above range, the unevenness of orientation is small, which reduces warping when heat processing for lamination is performed and facilitates stacking. If the difference between the maximum and minimum orientation angles is less than 0.5°, it is necessary to make the difference between the maximum and minimum orientation angles extremely small, and the molecular chains may become too uniformly aligned, which may make the electrolyte membrane reinforcing member prone to tearing. If the difference between the maximum and minimum orientation angles exceeds 20.0°, there is a risk that warping during lamination will increase and the flatness will decrease. The difference between the maximum and minimum orientation angles is more preferably 3.0° or more, and even more preferably 5.0° or more. The difference is more preferably 18.0° or less, and even more preferably 16.0° or less.

[0083] In the electrolyte membrane reinforcing member of the present invention, it is preferable that the thickness variation when measuring the outer periphery of the frame-shaped portion of the film layer at 10 mm intervals in at least one film layer is 0.5% or more and 10.0% or less. In the present invention, the thickness measurement is performed at a position 5 mm inward from the outer periphery of the rectangular frame-shaped electrolyte membrane reinforcing member. Within the above range, the thickness variation is small when stacked, and stacking can be easily performed. The thickness variation in at least one film layer of the electrolyte membrane reinforcing member is more preferably 1.0% or more. The thickness variation in at least one film layer of the electrolyte membrane reinforcing member is more preferably 8.0% or less, and even more preferably 6.0% or less. When a film with low thickness variation and orientation variation, as described later, is used as the film layer of the electrolyte membrane reinforcing member, the thickness variation of the electrolyte membrane reinforcing member tends to be low.

[0084] In the electrolyte membrane reinforcing member of the present invention, it is preferable that the tanδ peak temperature measured by dynamic viscoelasticity measurement in at least one film layer is 120°C or higher and 160°C or lower. When the tanδ peak temperature measured by dynamic viscoelasticity measurement is within the above range, heat resistance in the usage environment can be ensured, and long-term use is possible. The tanδ peak temperature is more preferably 125°C or higher. The tanδ peak temperature is more preferably 150°C or lower, and even more preferably 145°C or lower.

[0085] The bonding of the electrolyte membrane reinforcing member to the electrolyte membrane or separator in the present invention can be carried out via an adhesive layer constituting the electrolyte membrane reinforcing member, and known methods (for example, the methods described in Japanese Patent Application Publication No. 2015-2029 and Japanese Patent Application Publication No. 2022-69952) can be applied.

[0086] Cells used in fuel cells and water electrolysis devices have an electrolyte membrane reinforcing member having a biaxially oriented polyarylene sulfide film as a film layer in the present invention as the outer frame of the electrolyte membrane, and a catalyst layer, electrode substrate, and separator are sequentially laminated on both sides of the electrolyte membrane. Of these, those in which catalyst layers are laminated on both sides of the electrolyte membrane (i.e., a layer configuration of catalyst layer / electrolyte membrane / catalyst layer) are called catalyst-layered electrolyte membranes (CCMs), and those in which catalyst layers and gas diffusion substrates are sequentially laminated on both sides of the electrolyte membrane (i.e., a layer configuration of gas diffusion substrate / catalyst layer / electrolyte membrane / catalyst layer / gas diffusion substrate) are called membrane electrode assemblies (MEAs).

[0087] Common methods for manufacturing CCM include a coating method in which a catalyst layer paste composition for forming a catalyst layer is applied to the surface of the electrolyte membrane and dried, and a transfer method in which only the catalyst layer is prepared on a substrate and this catalyst layer is transferred to laminate the catalyst layer onto the electrolyte membrane. The edges of the electrolyte membrane in the CCM or MEA are overlapped with the periphery of the opening of the film of the present invention, which has a frame-shaped adhesive layer cut out, and the CCM and electrolyte membrane reinforcing member are attached by heat pressing.

[0088] When fabricating MEAs by pressing, known methods can be applied (for example, the chemical plating method described in Electrochemistry, 1985, 53, p.269, and the hot press bonding method for gas diffusion electrodes described in Electrochemical Science and Technology, 1988, 135, 9, p.2209, edited by the Electrochemical Society). The temperature, tension, and pressure during pressing should be appropriately selected depending on the thickness of the electrolyte membrane, the moisture content, and the catalyst layer and electrode substrate. Specific pressing methods include roll presses with specified pressure and clearance (for example, Japanese Patent Application Publication No. 2007-180031) and flat plate presses with specified pressure. From the viewpoint of industrial productivity and suppression of thermal decomposition of polymer materials with ionic groups, it is preferable to perform the process in the range of room temperature to 200°C.

[0089] The fuel cell and water electrolysis device according to the present invention will be described below. The fuel cell in this invention has a MEA using the biaxially oriented polyarylene sulfide film of this invention. By using the biaxially oriented polyarylene sulfide film of this invention in the fuel cell, processability is excellent, leading to a reduction in stack assembly yield.

[0090] The water electrolysis apparatus according to the present invention has a MEA using the biaxially oriented polyarylene sulfide film according to the present invention. By using the biaxially oriented polyarylene sulfide film according to the present invention in the water electrolysis apparatus, processability is excellent, leading to a reduction in stack assembly yield.

[0091] Next, we will describe a metallized film using the biaxially oriented polyarylene sulfide film of the present invention, a current collector foil and film capacitor using the same, and methods for manufacturing them.

[0092] The biaxially oriented polyarylene sulfide film of the present invention is preferably a metallized film having a metal layer on at least one side. In addition to circuit substrates, the biaxially oriented polyarylene sulfide film of the present invention can be used as a current collector foil or capacitor because it exhibits excellent orientation uniformity and thickness variation even when thinned. To form a metallized film, a metal layer must be present on at least one surface, and one or more of the following metals may be used: copper, copper alloy, aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. For lithium-ion batteries, it is preferable that the metal layer is aluminum for the positive electrode current collector foil and copper for the negative electrode current collector foil. For sodium-ion batteries, the positive electrode current collector foil may be aluminum and the negative electrode current collector foil may be copper, or both the positive and negative electrode current collector foils may be aluminum. As methods for forming the metal layer, vacuum deposition, sputtering, electrolytic plating, electroless plating, etc., are preferably used, and these methods may be combined.

[0093] The metallized film of the present invention can be made into an electrode plate by forming an electrode material layer on at least one surface. As electrode materials, lithium-containing metal oxides such as lithium cobaltate, lithium manganeseate, and lithium nickelate, or lithium-containing metal phosphorus oxides such as lithium iron phosphate and lithium iron manganese phosphate can be used as positive electrodes for lithium-ion batteries, and sodium-containing metal oxides such as sodium-containing metal oxides, sodium-containing metal phosphorus oxides, and sodium-containing Prussian blue analogs can be used as positive electrodes for sodium-ion batteries. Acetylene black, Ketjen black, carbon nanotubes, and graphene may be used as conductive materials, and polyvinylidene fluoride may be used as a binder. As a negative electrode, carbon materials such as graphite, carbon black, acetylene black, hard carbon, soft carbon, carbon nanotubes, and graphene, lithium alloy materials such as tin and silicon, and active materials such as lithium titanate and metallic lithium can be used, and carboxymethylcellulose, styrene-butadiene copolymer, and polyvinylidene fluoride can be used as binders.

[0094] The electrode is prepared by first dispersing an active material and a conductive additive in a binder resin solution to create an electrode coating solution. This coating solution is then applied to a metal foil or metallized film, and the solvent is dried to obtain the positive and negative electrodes, respectively. The thickness of the coating film after drying is preferably 30 μm to 500 μm. Furthermore, it is preferable to apply pressure to the active material layer formed on the metallized film using a rolling method such as a roll press to densify the active material layer. The active material layer may also be further densified by heating the rolls during rolling. Since the metallized film of the present invention has excellent dimensional stability at high temperatures, it is possible to produce electrodes with excellent flatness even when heated at high temperatures during solvent drying, thereby improving productivity.

[0095] A lithium secondary battery can be created by stacking multiple electrode groups, each with a lithium secondary battery separator placed between the positive and negative electrodes so as to be in contact with the active material layer of each electrode, or by winding a winding body in which the positive electrode, separator, and negative electrode are stacked and enclosed in an outer material such as a metal can or aluminum laminate film. The metallized film using the biaxially oriented polyarylene sulfide film of the present invention has excellent processability, exhibits excellent processability with small thickness variation when many are stacked during winding as a current collector foil, and produces a stable winding body with little winding misalignment even at high speed and high tension winding.

[0096] For example, the film capacitor of the present invention can be obtained by laminating or winding the metallized film of the present invention described above in various ways. A preferred manufacturing method for a wound film capacitor is as follows.

[0097] Aluminum is deposited onto one side of a biaxially oriented polyarylene sulfide film under reduced pressure. The aluminum is deposited in a stripe pattern with a margin running along the longitudinal direction. Next, a blade is inserted into the center of each deposited area and the center of each margin to create a tape-shaped reel with a margin on one side of the surface. Two of these tape-shaped reels, one with a left margin and one with a right margin, are stacked and wound together so that the deposited portion extends beyond the margin in the width direction, thereby obtaining a wound body.

[0098] When vapor deposition is performed on both sides, one side is vapor-deposited in a stripe pattern with a margin running along the longitudinal direction, and the other side is vapor-deposited in a stripe pattern so that the longitudinal margin is located in the center of the vapor-deposited area on the back side. Next, a blade is inserted into the center of the margin on both the front and back sides to create a slit, and a tape-shaped winding reel is produced with a margin on one side on each side (for example, if there is a margin on the right side of the front side, there will be a margin on the left side of the back side). The obtained reel and one unvapor-deposited laminated film are stacked in pairs so that the metallized film extends beyond the laminated film in the width direction, and the two layers are wound together to obtain a wound body. The metallized film using the biaxially oriented polyarylene sulfide film of the present invention has excellent processability, exhibits excellent processability with small thickness variation when many layers are stacked during winding as current collector foil, and produces a stable wound body with little winding misalignment even at high speed and high tension winding.

[0099] One method for obtaining the film capacitor of the present invention from the metallized film of the present invention is to remove the core material from the wound body prepared as described above, press it, spray Metallicon onto both end faces to form external electrodes, and weld lead wires to the Metallicon to form a wound film capacitor. Film capacitors have a wide range of applications, including power control units for electric vehicles such as electric cars, hybrid cars, and fuel cell vehicles, electric aircraft such as drones, railway vehicles, solar and wind power generation, and general home appliances, and the film capacitor of the present invention can be suitably used in these applications. In addition, the polypropylene film of the present invention can be used in various applications such as packaging films, release films, process films, sanitary products, agricultural products, building materials, and medical products, and is particularly suitable for applications that include a heating process in film processing.

[0100] The biaxially oriented polyarylene sulfide film of the present invention can be manufactured by the process described above, and the resulting film has minimal orientation unevenness and thickness variation. Taking advantage of these characteristics, the film of the present invention can be suitably used as an electrical insulating paper for motors, in applications where it is important to suppress warping due to orientation unevenness and wrinkles due to thickness variation during lamination or bonding processes. When an electrical insulating paper for motors using the biaxially oriented polyarylene sulfide film of the present invention is used in a motor, it exhibits superior processability compared to conventional electrical insulating paper, leading to a reduction in yield during slot insertion. [Examples]

[0101] [Method for measuring characteristics] (1) Content of polyarylene sulfide resin The infrared absorption spectrum of the biaxially oriented polyarylene sulfide film of the present invention was measured by the ATR method using an infrared spectrophotometer (PerkinElmer Spectrum100 / Universal ATR (single reflection, crystal used: diamond / ZnSe)). From the obtained infrared absorption spectrum, the polyarylene sulfide resin content was determined from the ratio of peaks caused by φ-S stretching vibration groups based on the sulfide bonds of polyarylene sulfide to peaks caused by other substances. In order to convert the peak height ratio to a mass ratio, a calibration curve was created using samples with known mass ratios (e.g., olefins used as incompatible resins), and the polyarylene sulfide resin content was calculated from the ratio of polyarylene sulfide to the total amount of other substances.

[0102] (2) Collection of rolls to be evaluated While rewinding the intermediate product rolls obtained from each example and comparative example, slits were made in the width direction at ±200 mm, with the center of the intermediate product roll set to 0 mm, and from the cross-section to both ends at ±400 mm intervals, up to the ends of the intermediate product roll, to obtain a total of 5 film rolls. Of the obtained film rolls, the product rolls were designated as the 1st (left), 2nd, 3rd (center), 4th, and 5th (right) product rolls, starting from one end (left) to the other (right) end of the intermediate product roll, and the 1st, 3rd, and 5th product rolls were used as the measurement targets. For convenience, these measurement targets were designated as "-1" for the 1st roll, "-2" for the 3rd roll, and "-3" for the 5th roll. That is, in Example 1, the 1st roll (left end) was designated as Example 1-1, the 3rd roll (center) as Example 1-2, the 5th roll (right end) as Example 1-3, and so on, and the same notation was used for the other examples and comparative examples.

[0103] In this invention, a product was deemed acceptable if at least one of "-1", "-2", or "-3" satisfies the specified range.

[0104] (3-1) Thickness variation in the width direction of the film (%) Using an electronic micrometer K-306C (manufactured by Anritsu Keiki Co., Ltd.), a film sample was cut from the center of a 400 mm wide film roll of the biaxially oriented polyarylene sulfide film of the present invention, with dimensions of 300 mm in the width direction and 50 mm in the length direction. The thickness in the width direction of the film was continuously measured, and the following calculations were made from the maximum, minimum, and average thicknesses within that measurement. Widthwise thickness variation (%) = (Maximum thickness - Minimum thickness) / Average thickness × 100

[0105] (3-2) Thickness variation in the longitudinal direction of the film (%) Using an electronic micrometer K-306C (manufactured by Anritsu Keiki Co., Ltd.), a film sample was cut from the center of a 400 mm wide film roll of the biaxially oriented polyarylene sulfide film of the present invention, with dimensions of 50 mm in the width direction and 300 mm in the length direction. The thickness in the length direction of the film was continuously measured, and the following was calculated from the maximum, minimum, and average thicknesses within that measurement. Widthwise thickness variation (%) = (Maximum thickness - Minimum thickness) / Average thickness × 100

[0106] (4) Thickness variation (%) of the film layer used in the electrolyte membrane reinforcing member The film layer extracted from the electrolyte membrane reinforcement member was measured using a contact-type electronic micrometer (K-312A model) manufactured by Anritsu Corporation under an atmosphere of 23°C and 65% RH. Measurements were taken along the rectangular frame-shaped electrolyte membrane reinforcement member at 10 mm intervals, 5 mm from the outer edge to the inner edge, and the maximum and minimum thicknesses within these measurements were used to calculate the following: Thickness variation (%) of the film layer used in electrolyte membrane reinforcement members = (maximum thickness - minimum thickness) / average thickness × 100

[0107] (5) Orientation angle from the longitudinal direction of the film, and the difference between the maximum and minimum values ​​of the orientation angle. The biaxially oriented polyarylene sulfide film of the present invention was evaluated using a microwave transmission type molecular orientation meter MOA-6015 (manufactured by Oji Instruments Co., Ltd.) at a frequency of 15 GHz. The center of a 400 mm wide film roll was cut to a size of 300 mm in the film width direction and 30 mm in the longitudinal direction. The cut film sample was further cut every 30 mm in the width direction, resulting in a total of 10 film samples of size 30 mm in the film width direction and 30 mm in the longitudinal direction. The orientation angle was determined with the longitudinal direction of the film as the 0° direction of the measuring instrument (the range of the measured orientation angle is -90° to 90°). The average of the orientation angles at 10 measurement points in the width direction was taken as the orientation angle from the longitudinal direction of the film, and the difference between the maximum and minimum values ​​was calculated from the orientation angles at 10 measurement points in the width direction using the following formula. (i) If all 10 orientation angle points measured in the width direction have orientation angles greater than -35° and less than 35°, the difference between the maximum and minimum orientation angles shall be used as the representative value. (ii) If all 10 orientation angle points measured in the width direction are between -90° and -55°, the difference between the maximum and minimum orientation angles shall be used as the representative value. (iii) If all 10 orientation angles measured in the width direction are greater than 55° and less than or equal to 90°, the difference between the maximum and minimum orientation angles shall be taken as the representative value. (iv) If all 10 orientation angle points measured in the width direction fall within both the ranges of -90° or greater and less than -55°, and greater than 55° and less than or equal to 90°, then 180° - (the difference between the maximum and minimum orientation angles) shall be used as the representative value.

[0108] (6) Orientation angle of the film layer used in the electrolyte membrane reinforcement member, and the difference between the maximum and minimum values ​​of the orientation angle. The film layer extracted from the electrolyte membrane reinforcement member was evaluated at a frequency of 15 GHz using a microwave transmission type molecular orientation analyzer MOA-6015 (manufactured by Oji Instruments Co., Ltd.). One of the outer peripheral directions of the rectangular frame-shaped electrolyte membrane reinforcement member was designated as the 0° direction of the measuring instrument, and the frame-shaped portion of the film layer used in the electrolyte membrane reinforcement member was cut along the outer circumference into 30 mm x 30 mm pieces on all four sides. The orientation angle of the film layer extracted from the electrolyte membrane reinforcement member was determined from the cut samples (the range of the measured orientation angle is -90° to 90°). The average value of the orientation angle of the frame-shaped portion of the film layer used in the electrolyte membrane reinforcement member was taken as the orientation angle of the film layer, and the difference between the maximum and minimum orientation angles of the upper part of the frame was calculated using the following formula. (i) If the orientation angles measured in the width direction are all greater than -35° and less than 35°, the difference between the maximum and minimum orientation angles shall be used as the representative value. (ii) If all orientation angles measured in the width direction are between -90° and -55°, the difference between the maximum and minimum orientation angles shall be used as the representative value. (iii) If the orientation angles measured in the width direction are all greater than 55° and less than or equal to 90°, the difference between the maximum and minimum orientation angles shall be used as the representative value. (iv) If the orientation angles measured in the width direction all fall within the ranges of -90° or greater and less than -55°, and greater than 55° and less than or equal to 90°, then 180° - (the difference between the maximum and minimum orientation angles) shall be used as the representative value.

[0109] (7) 130℃ modulus of elasticity The biaxially oriented polyarylene sulfide film of the present invention was subjected to a tensile test in accordance with JIS K7127 (1999) using a tensile testing machine (A&D Company, Limited / RTG-1210). A sample film with a width of 10 mm was set so that the distance between the chucks was 50 mm, and a tensile test was performed at a temperature of 130°C and a tensile speed of 300 mm / min.

[0110] The modulus of elasticity was calculated by setting the displacement start point to 0 mm and the end point to 10 mm, determining the load difference within the measurement range from 0 mm to 10 mm with a calculation pitch of 0.2 mm, and using the 2nd, 3rd, and 4th coordinates from the maximum value as the raw data, linearizing the data using the least squares method, and the slope of the resulting line was defined as the modulus of elasticity. Five samples were cut out so that the direction of the test length was in the longitudinal direction and the width direction, and measurements were taken for each, with the average calculated for each. Measuring device: A&D Company, Limited / RTG-1210 Sample size: 150mm length x 10mm width Chuck spacing: 50mm Tensile speed: 300 mm / min Measurement environment: 130℃ Analysis conditions: Displacement mode; Start point: 0 mm; End point: 10 mm; Pitch: 0.2 mm

[0111] (8) Center surface average roughness SRa The average center surface roughness SRa of the biaxially oriented polyarylene sulfide film of the present invention was determined using a Surfcorder ET30HK manufactured by Kosaka Laboratory under the following conditions. Stylus curvature radius: 2μm Cut-off: 0.25mm Measurement length: 0.5mm Measurement interval: 5 μm Number of measurements: 40

[0112] (9) Calcium ion content A biaxially oriented polyarylene sulfide film of the present invention was cut with ceramic scissors to a weight of 4 g and used as an analytical sample. After washing the surface with ultrapure water, it was heated and extracted for 2 hours in 100 mL of pre-boiled 5% by mass nitric acid solution. The extracted solution was qualitatively analyzed by ICP mass spectrometry (ICP-MS) to determine the amount of calcium ions extracted per unit mass of sample. Equipment: Agilent 8800 manufactured by Agilent Technologies

[0113] (10) Values ​​on the vertical axis of the differential molecular weight distribution curve (dw / dLogM) A differential molecular weight distribution curve was prepared for the biaxially oriented polyarylene sulfide film of the present invention according to JIS K7252 (2016). Specifically, 5 mL of 1-chloronaphthalene (1-CN) was added to 5 mg of the film sample and gently stirred at 210-220°C for 20 minutes (dissolution was visually confirmed). The mixture was then filtered using a 0.5 μm filter. A GPC curve was obtained by measurement under the following conditions. The obtained GPC curve was transformed using a molecular weight calibration curve created by approximating the logarithm of the polystyrene molecular weight with a cubic equation of the elution time, and the weight fraction was calculated normalized to a peak area of ​​1. Note that the molecular weight is a relative value based on polystyrene, and a differential molecular weight distribution curve can be created by plotting the logarithm of molecular weight M (LogM) on the x-axis and the weight fraction (dw / dLogM) on the y-axis. From the obtained differential molecular weight distribution curve, the y-axis value (dw / dLogM) was read when the x-axis value (LogM) was 4.0, 5.2, and 5.5. Equipment: High temperature GPC equipment (equipment No. GPC-H-2, PL-GPC220 manufactured by Polymer Laboratories) Detector: Differential refractive index detector (RI) Data interval: every 0.5 seconds Column: Shodex UT-G (Guard Column) PLgel 10m MIXED-B-LS (2 rolls) (8.0mm x 30cm, manufactured by Polymer Laboratories) Solvent: 1-Chloronaphthalene Flow rate: 0.7mL / min Column temperature: 210℃ Injection volume: 0.200mL Standard sample: Monodisperse polystyrene manufactured by Tosoh Corporation

[0114] (11) tanδ peak obtained by dynamic viscoelasticity measurement of the film layer used in the electrolyte membrane reinforcement member The film layer extracted from the electrolyte membrane reinforcement member was cut into strips 50 mm long and 5 mm wide, with the direction of the length parallel to the direction of the larger average value of the orientation angle of the electrolyte membrane reinforcement member. Both ends were set in chucks with a distance of 10 mm between the chucks and subjected to measurement. The loss tangent tanδ = E" / E' was determined from the storage modulus E' and loss modulus E'' obtained at each temperature. The peak of the observed peak in the obtained tanδ curve was read and defined as the tanδ peak temperature. Device: EXSTAR DMS6100 (manufactured by Seiko Instruments Inc.) Measurement mode: Tensile Measurement temperature range: 25°C to 280°C Heating rate: 3°C / min Measurement atmosphere: Air Frequency: 1Hz Displacement: 10.0 μm

[0115] (12) Resonance parameter (Q value) The biaxially oriented polyarylene sulfide film of the present invention was evaluated at a frequency of 15 GHz using a microwave molecular orientation analyzer (MOA-6015, manufactured by Oji Instruments Co., Ltd.). The center of the film roll was cut to a size of 300 mm in the film width direction and 30 mm in the longitudinal direction. This cut film sample was further cut into 30 mm intervals in the width direction, resulting in a total of 10 film samples of 30 mm in width direction and 30 mm in longitudinal direction. For each measurement, the measurement angle of the film was rotated from 0° in 30° increments, changing the angle at 6 points up to 150°. The resonance parameter (Q value) at each angle was measured, and the average value was calculated.

[0116] (13) Minor endothermic peak temperature (T-meta) The biaxially oriented polyarylene sulfide film of the present invention was subjected to a differential scanning calorimeter (DSC) manufactured by Rigaku Corporation (Thermo plus EVO2 DSCvesta-SL) in accordance with JIS K7121 (1999). A 5 mg sample of the film was sealed in an aluminum pan and heated from 25°C to 350°C at a heating rate of 20°C / min. The peak temperature of the observed endothermic melting peak was defined as the melting point (Tm), and the minute endothermic peak temperature appearing in the temperature range of 150°C to Tm°C was defined as T-meta. Here, the melting point was defined as the point where the difference from the baseline of the DSC chart was maximum. The minute endothermic peak was observed in the first run of the DSC and not observed in the second run after the temperature was raised above Tm and the thermal history was erased. Therefore, it can be confirmed by comparing the two DSC charts. Measurements were performed three times for each sample, and the average value of the obtained values ​​was defined as the melting point and minute endothermic peak (T-meta) of that sample.

[0117] (14) Flatness A hot-melt adhesive (Toagosei Co., Ltd.: "Aronmelt" PPET1303S) was applied to the biaxially oriented polyarylene sulfide film of the present invention using a bar coater, and dried in an oven heated to 100°C for 60 seconds to obtain a polyarylene sulfide film laminate with a 10 μm adhesive layer thickness of biaxially oriented polyarylene sulfide / adhesive layer. The obtained polyarylene sulfide film laminate was cut to a size of 150 mm × 150 mm, stacked so that the adhesive layers were in contact with each other, and bonded using a press machine at 160°C, 2.0 MPa, and 30 seconds. The obtained compressed film was placed on a surface plate, and the curl state of the four corners was observed in that state. The average value of the amount of warping (mm) at the four corners was calculated and evaluated according to the following criteria. A: The amount of warping is less than 5 mm. B: The amount of warping is 5mm or more and less than 10mm. C: The amount of warping is 10mm or more and less than 15mm. D: The amount of warping is 15 mm or more.

[0118] (15) Processability (I) 100 sheets of the biaxially oriented polyarylene sulfide film of the present invention, obtained by cutting 100 sheets of the film roll's center section in the film width direction in the longitudinal direction (150 mm x 150 mm), were stacked between two steel plates (150 mm x 150 mm, 250 μm thick). Pressure-sensitive paper (Fujifilm's "Prescale" (registered trademark) LW) was then sandwiched between the 25th and 26th sheets, the 50th and 51st sheets, and the 75th and 76th sheets. Using a press with uniform surface pressure, pressure was applied for 10 minutes at room temperature and a pressure of 4 MPa, and then released. The color change of the pressure-sensitive paper was evaluated according to the following criteria. A: A uniform pressure is applied to all of the pressure-sensitive paper. B: A pressure distribution can be seen in a portion of the pressure-sensitive paper. C: Pressure distribution can be observed across multiple pressure-sensitive papers. D: The pressure distribution is large.

[0119] (16) Processability (II) The biaxially oriented polyarylene sulfide film of the present invention was wound onto a 3-inch core to a length of 500 m, and subjected to an aging treatment in an oven maintained at 80°C for 72 hours. From the roll sample, a 300 mm wide x 250 mm long section was cut from the center of the film in the width direction, and its appearance was evaluated as follows. A: No wrinkles or warping occur. B: Slight wrinkles or warping may occur. C: Small wrinkles and warping may occur. D: Other (e.g., large wrinkles, unevenness, or warping)

[0120] (17) Transportability (I) The biaxially oriented polyarylene sulfide film of the present invention was slit to a width of 400 mm and wound into a continuous 1000 m slit roll. At that time, the number of defects originating from scratches generated on the roll surface was counted using a defect detector and evaluated as follows. A: The number of defects due to scratches in the roll is 9 or less. B: The number of defects due to scratches in the roll is between 10 and 50. C: The number of defects due to scratches exceeds 50 within the roll.

[0121] (18) Transportability (II) The biaxially oriented polyarylene sulfide film of the present invention was unwound and transported on a roll at a winding speed of 40 m / min in a drying oven heated to 120°C for 15 seconds, and then wound up. A length of 1000 m was carried out continuously, and the above processing was performed on 5 rolls. The transportability (II) was evaluated from the winding shape of the resulting rolls as follows. A: Out of 5 rolls, one or fewer rolls have wrinkles. B: Two or more of the five rolls have wrinkles.

[0122] (19) Transportability (III) From the roll samples evaluated for transportability (II), a section measuring 300 mm in width and 250 mm in length was cut from the center of the film, and the condition of wrinkles and unevenness was visually observed and evaluated as follows. A: No wrinkles or unevenness occur. B: Slight wrinkles, unevenness, and curls may occur. C: Small wrinkles, bumps, and curls may occur. D: Other (e.g., large wrinkles, unevenness, or curling)

[0123] (20) Gas leak properties A hot-melt adhesive (Toagosei Co., Ltd.: "Aronmelt" (registered trademark) PPET1303S) was applied to the biaxially oriented polyarylene sulfide film of the present invention using a bar coater as the adhesive layer, and dried in an oven heated to 100°C for 60 seconds to obtain a polyarylene sulfide film laminate with a biaxially oriented polyarylene sulfide / adhesive layer thickness of 10 μm.

[0124] Next, using a 90mm x 140mm perfluorosulfonic acid resin (DuPont: "Nafion" (registered trademark) 117) as the electrolyte membrane, electrolyte membrane reinforcing members (outer circumference 150mm x 200mm, inner circumference 88mm x 138mm) were punched out in a frame shape from the polyarylene sulfide film laminate as shown in Figure 2. These were set on both sides of the electrolyte membrane, and the adhesive layers were overlapped so that they were in contact with each other. The two layers were then bonded at 115°C, 3MPa, for 45 seconds to produce an electrolyte membrane with electrolyte membrane reinforcing members. Five of these electrolyte membranes with electrolyte membrane reinforcing members were stacked together to form an evaluation cell (electrode area 126cm²). 2 It was incorporated into the system and used as a clamping evaluation cell to achieve a predetermined surface pressure.

[0125] The evaluation cell was subjected to 1000 cycles using a thermal cycle tester (TSE-11 thermal shock device manufactured by ESPEC Corporation), with one cycle consisting of -40°C for 30 minutes and 125°C for 30 minutes. Nitrogen gas was then sealed into the gas passage of the JARI standard cell to a pressure of 300 kPa, and the cell was left standing for 2 hours. The presence or absence of gas leaks was evaluated by the pressure change, and the cell's durability was evaluated according to the following criteria. A: There is no change in the pressure of the enclosed gas, so there are no problems in practical use. B: The pressure of the sealed gas decreased, causing a gas leak.

[0126] (Reference Example 1) Preparation of polyphenylene sulfide resin granules (PPS granules 1) In a 1-kiloliter stainless steel container equipped with a stirrer, 1 kilomol of 47% sodium hydrosulfide, 1.02 kilomol of 47% sodium hydroxide, 1.6 kilomol of N-methyl-2-pyrrolidone (NMP), 0.3 kilomol of sodium acetate, and 100 kilograms of deionized water were charged. The mixture was gradually heated to 235°C over approximately 180 minutes while stirring at 240 rpm and passing nitrogen through it at atmospheric pressure. After distilling off 209 kilograms of water and 0.4 kilograms of NMP, the reaction vessel was cooled to 160°C. The amount of hydrogen sulfide released was 0.02 kilomol. To the residual mixture, 1.02 kilomol of p-dichlorobenzene (p-DCB) and 2.40 kilomol of NMP were added. The reaction vessel was then sealed under nitrogen gas. The temperature was raised from 160°C to 220°C over 100 minutes while stirring at 400 rpm, and the reaction was carried out at 220°C for 225 minutes. Next, the temperature was raised from 220°C to 255°C over 60 minutes, and 0.8 kilomol of water was added to the system over 10 minutes, and the reaction was continued for 380 minutes. After that, the temperature was cooled from 255°C to 200°C over 100 minutes. After reaching 150°C, it was rapidly cooled to near room temperature using a fan. The contents were removed, 1 kiloliter of NMP was added, and the mixture was stirred at 85°C for 30 minutes, after which the solvent and solids were filtered off using an 80-mesh sieve. 1 kiloliter of NMP was added to the obtained solids, and the mixture was stirred at 85°C for 30 minutes and filtered off. 1 kiloliter of warm water was added to the obtained solids, and the mixture was stirred at 70°C for 30 minutes and filtered off. This process was repeated three times. 4.5 kilograms of calcium acetate monohydrate and 1 kiloliter of aqueous solution of warm water were added to the obtained solids, and the mixture was stirred at 70°C for 30 minutes and filtered off. The obtained solid was mixed with 1 kiloliter of warm water and stirred at 70°C for 30 minutes, followed by filtration. This process was repeated twice. The mixture was then dried under reduced pressure at 120°C for 5 hours to obtain PPS granules 1, which have a high molecular weight and a narrow molecular weight distribution.

[0127] (Reference Example 2) Preparation of polyphenylene sulfide resin granules (PPS granules 2) In a 1-kiloliter stainless steel container equipped with a stirrer, 1 kilomol of 47% sodium hydrosulfide, 1.02 kilomol of 47% sodium hydroxide, 1.65 kilomol of N-methyl-2-pyrrolidone (NMP), 0.3 kilomol of sodium acetate, and 100 kilograms of deionized water were charged. The mixture was gradually heated to 235°C over approximately 180 minutes at atmospheric pressure while stirring at 240 rpm and passing nitrogen through it. After distilling off 209 kilograms of water and 0.4 kilograms of NMP, the reaction vessel was cooled to 160°C. The amount of hydrogen sulfide released was 0.02 kilomol. To the residual mixture, 0.0004 kilomol of 1,2,4-trichlorobenzene, 1.02 kilomol of p-dichlorobenzene (p-DCB), and 1.35 kilomol of NMP were added. The reaction vessel was then sealed under nitrogen gas. The temperature was raised from 160°C to 270°C over 180 minutes while stirring at 400 rpm, and the reaction was carried out at 270°C for 135 minutes. The mixture was cooled from 270°C to 200°C over 100 minutes. Simultaneously with the start of cooling, 0.8 kilomol of water was added to the system over 10 minutes. After reaching 200°C, the mixture was rapidly cooled to near room temperature using a fan. The contents were removed, 1 kiloliter of NMP was added, and the mixture was stirred at 85°C for 30 minutes, after which the solvent and solids were filtered off using an 80-mesh sieve. 1 kiloliter of NMP was added to the obtained solids, and the mixture was stirred at 85°C for 30 minutes and filtered off. 1 kiloliter of warm water was added to the obtained solids, and the mixture was stirred at 70°C for 30 minutes and filtered off. This process was repeated three times. 1 kiloliter of 0.005 wt% calcium acetate aqueous solution and warm water were added to the obtained solids, and the mixture was stirred at 70°C for 30 minutes and filtered off. To the obtained solid, 1 kiloliter of warm water was added and the mixture was stirred at 70°C for 30 minutes, followed by filtration. This process was repeated twice. The mixture was then dried under reduced pressure at 120°C for 5 hours to obtain PPS granules 2, which had a slightly lower molecular weight than Reference Example 1.

[0128] (Reference Example 3) Preparation of polyphenylene sulfide resin granules (PPS granules 3) Except for changing the amount of 1,2,4-trichlorobenzene in Reference Example 2 to 0.003 kilomol, the same procedure as in Reference Example 2 was performed to obtain PPS granules 3, which contained more high molecular weight components and had a broader molecular weight distribution than Reference Example 1.

[0129] (Reference Example 4) Preparation of polyphenylene sulfide resin granules (PPS granules 4) Except for extending the reaction time at 270°C to 100 minutes as in Reference Example 2 and increasing the amount of low molecular weight components compared to Reference Example 2, the same procedure was followed to obtain PPS granules 4, which have a high amount of low molecular weight components.

[0130] (Reference Example 5) Preparation of polyphenylene sulfide resin granules (PPS granules 5) The procedure for Reference Example 1, "The temperature was raised from 160°C to 220°C over 100 minutes while stirring at 400 rpm, and the reaction was carried out at 220°C for 225 minutes. Then, the temperature was raised from 220°C to 255°C over 60 minutes, and 0.8 kilomolars of water were added to the system over 10 minutes, and the reaction was continued for 380 minutes," was modified to "Raise the temperature from 160°C to 220°C over 100 minutes, gradually changing the temperature until the final temperature reached 320°C, and allowing the reaction to proceed for 8 hours." The same procedure as in Reference Example 1 was followed, except that the temperature was changed to "Raise the temperature from 160°C to 220°C over 100 minutes, and allow the reaction to proceed for 8 hours while gradually changing the temperature until the final temperature reached 320°C." This yielded PPS granules 5, which have a lower molecular weight than those in Reference Example 1.

[0131] (Reference Example 6) Preparation of polyphenylene sulfide resin granules (PPS granules 6) Except for the reaction time at 255°C being 440 minutes, the procedure was the same as in Reference Example 1, and PPS granules 6 with a narrower molecular weight distribution than in Reference Example 1 were obtained.

[0132] (Reference Examples 7-12) Method for manufacturing PPS pellets (PPS1-6) PPS granules 1 to 6, prepared in Reference Examples 1 to 6, were each placed into a vented, co-rotating twin-screw compounding extruder (manufactured by Japan Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5) heated to 310°C. They were melt-extruded at a residence time of 90 seconds and a screw rotation speed of 160 revolutions per minute to produce strands. After cooling with water at 25°C, they were immediately cut to produce chips, thereby obtaining PPS 1 to 6.

[0133] (Reference Example 13) Method for manufacturing PPS particle pellets (PPS particle 1) 10% by mass of silica spherical fine particles with an average particle size of 0.5 μm (Nippon Shokubai Co., Ltd. "Sea Hoster" KE P50) and 90% by mass of PPS granules 1 prepared in Reference Example 1 were mixed. The resulting mixture was melt-extruded in the same manner as in Reference Example 7 to obtain PPS particle pellets (PPS particles 1) with a particle content of 10% by mass.

[0134] (Reference Example 14) Method for manufacturing PPS particle pellets (PPS particle 2) A slurry was prepared by dispersing calcium carbonate particles with an average particle size of 1.0 μm in ethylene glycol at a concentration of 50% by mass. After filtering this slurry, it was mixed with PPS granules 1 prepared in Reference Example 1 using a Henschel mixer to achieve a calcium carbonate content of 10% by mass. The resulting mixture was melt-extruded in the same manner as in Reference Example 7 to obtain PPS particle pellets (PPS particles 2) with a particle content of 10% by mass.

[0135] (Example 1) 75 parts by mass of PPS pellets (PPS1) prepared in Reference Example 7, 15 parts by mass of PPS3 prepared in Reference Example 9, and 10 parts by mass of PPS particles 1 prepared in Reference Example 13 were dry blended and then dried under reduced pressure at 180°C for 3 hours. Next, the mixture was fed into an extruder, melted at a temperature of 310°C under a nitrogen atmosphere, and introduced into a T-die. Next, the mixture was extruded from the T-die to form a molten single-layer sheet, and this molten single-layer sheet was cast onto a casting drum rotating at 4.0 m / min and maintained at a surface temperature of 25°C, while being cooled and solidified by electrostatic application to obtain an unstretched film. The obtained unstretched film was stretched in the longitudinal direction of the film at a magnification of 4.0 times (MD stretching) at a stretching temperature of 100°C using a longitudinal stretcher consisting of multiple heated roll groups, utilizing the difference in peripheral speed of the rolls. Subsequently, the film was supported at both ends with clips and guided to a tenter. It was stretched at a stretching temperature of 102°C at a magnification of 3.3 times in the width direction (TD stretching), then stretched at 230°C at a magnification of 1.10 times in the width direction (TD stretching 2), and heat-set for 20 seconds in a tenter heated to 235°C. Next, the first relaxation treatment (Rx1) was performed in a tenter at 234°C with a relaxation rate of 4.0%, followed by a second relaxation treatment (Rx2) in a tenter at 200°C with a relaxation rate of 1.5%. After cooling to room temperature, the film edges were removed to obtain an intermediate product roll of biaxially oriented polyarylene sulfide film with a width of 2000 mm. While rewinding the obtained intermediate product roll, slits were made 200 mm in the width direction from the center of the intermediate product roll and 400 mm each from the cross-section to both ends, resulting in a total of 5 film rolls. The electrolyte membrane reinforcing member was obtained by punching out a material so that the outer circumference had a side length of 150 mm in the width direction and a side length of 200 mm in the longitudinal direction, and the inner circumference had a side length of 88 mm in the width direction and a side length of 138 mm in the longitudinal direction. The physical properties and characteristics of the film are shown in the table.

[0136] (Examples 2-9, Comparative Examples 1-6) A biaxially oriented polyarylene sulfide film was obtained in the same manner as in Example 1, except that the raw material composition and film-forming conditions for each layer were as shown in the table. The thickness was adjusted by controlling the extrusion rate and the casting drum speed. The physical properties and evaluation results of the obtained film are shown in the table.

[0137] [Table 1]

[0138] [Table 2]

[0139] [Table 3]

[0140] [Table 4]

[0141] [Table 5]

[0142] [Table 6]

[0143] [Table 7]

[0144] [Table 8]

[0145] [Table 9]

[0146] [Table 10] [Industrial applicability]

[0147] The biaxially oriented polyarylene sulfide film of the present invention can be widely used as a component in fuel cells, water electrolyzers, secondary batteries, film capacitors, motors, and the like. [Explanation of symbols]

[0148] 1: Electrolyte membrane reinforcing member 2: Opening 3: Electrolyte membrane 4: Adhesive layer 5: Polyarylene sulfide film

Claims

1. A biaxially oriented polyarylene sulfide film comprising polyarylene sulfide resin as the main component, wherein the thickness variation in the film width direction is 0.5% or more and 10.0% or less over a 300 mm width centered on the center of the film width direction, the orientation angle from the longitudinal direction of the film is greater than -35° and less than 35°, greater than -90° and less than -55°, or greater than 55° and 90° or less, and the difference between the maximum and minimum values ​​of the orientation angle is 0.5° or more and 20.0° or less.

2. The biaxially oriented polyarylene sulfide film according to claim 1, wherein the orientation angle is greater than -30° and less than 30°, or -90° or more and less than -60°, or greater than 60° and less than or equal to 90°.

3. The biaxially oriented polyarylene sulfide film according to claim 1 or 2, wherein the thickness variation in the film width direction is 0.5% or more and 6.0% or less in a 300 mm width centered on the center of the film width direction.

4. The biaxially oriented polyarylene sulfide film according to claim 1 or 2, wherein the modulus of elasticity measured at 130°C is 1.0 GPa or more in the longitudinal and width directions.

5. The biaxially oriented polyarylene sulfide film according to claim 1 or 2, wherein the mean center surface roughness SRa of at least one surface is 10 nm or more and 100 nm or less.

6. The biaxially oriented polyarylene sulfide film according to claim 1 or 2, wherein the calcium ion concentration is 10 ppm by mass or less.

7. The biaxially oriented polyarylene sulfide film according to claim 1 or 2, wherein, in the differential molecular weight distribution curve measured by gel permeation chromatography, the value on the vertical axis (dw / dLogM) when the value on the horizontal axis (LogM) is 5.2 is 0.10 or more and 0.60 or less.

8. The biaxially oriented polyarylene sulfide film according to claim 1 or 2, wherein, in the differential molecular weight distribution curve measured by gel permeation chromatography, the value on the vertical axis (dw / dLogM) when the value on the horizontal axis (LogM) is 4.0 is 0.10 or more and 0.40 or less.

9. The biaxially oriented polyarylene sulfide film according to claim 1 or 2, wherein, in the differential molecular weight distribution curve measured by gel permeation chromatography, the value on the vertical axis (dw / dLogM) when the value on the horizontal axis (LogM) is 5.5 is 0.01 or more and 0.25 or less.

10. A biaxially oriented polyarylene sulfide film according to claim 1 or 2, wherein the resonance parameter (Q value) is 4600 or more and 5200 or less.

11. The biaxially oriented polyarylene sulfide film according to claim 1 or 2, wherein the minute endothermic peak temperature (T-meta) determined by differential scanning calorimetry (DSC) is 200°C or higher (melting point - 20°C or lower).

12. A biaxially oriented polyarylene sulfide film roll obtained by winding the biaxially oriented polyarylene sulfide film according to claim 1 or 2.

13. An electrolyte membrane reinforcing member having a biaxially oriented polyarylene sulfide film as described in claim 1.

14. An electrolyte membrane reinforcing member having a biaxially oriented polyarylene sulfide film that satisfies conditions (a) and (b). (a) The calcium ion concentration is 10 ppm by mass or less. (b) In the differential molecular weight distribution curve measured by gel permeation chromatography, the value on the vertical axis (dw / dLogM) is between 0.15 and 0.60 when the value on the horizontal axis (LogM) is 5.

2.

15. The electrolyte membrane reinforcing member according to claim 14, wherein, in the differential molecular weight distribution curve measured by gel permeation chromatography, the value on the vertical axis (dw / dLogM) when the value on the horizontal axis (LogM) is 4.0 is 0.10 or more and 0.40 or less.

16. The electrolyte membrane reinforcing member according to claim 14 or 15, wherein, in the differential molecular weight distribution curve measured by gel permeation chromatography, the value on the vertical axis (dw / dLogM) when the value on the horizontal axis (LogM) is 5.5 is 0.01 or more and 0.25 or less.

17. An electrolyte membrane reinforcing member having a rectangular frame shape with an opening, wherein at least one film layer constituting the electrolyte membrane reinforcing member satisfies conditions (A) and (B). (A) The orientation angle is greater than -35° and less than 35°, greater than or equal to -90° and less than -55°, or greater than 55° and less than or equal to 90°. (B) The difference between the maximum and minimum values ​​of the orientation angle is 0.5° or more and 20° or less.

18. The electrolyte membrane reinforcing member according to claim 17, wherein the thickness variation when a film layer satisfying the above conditions (A) and (B) is measured at 10 mm intervals is 0.5% or more and 10.0% or less.

19. The electrolyte membrane reinforcement member according to claim 17 or 18, wherein the tanδ peak temperature of the film layer satisfying the above conditions (A) and (B) by dynamic viscoelasticity measurement is 120°C or higher and 160°C or lower.

20. The electrolyte membrane reinforcing member according to claim 17 or 18, wherein the film layer satisfying the above conditions (A) and (B) contains polyarylene sulfide resin as a main component.

21. A fuel cell having an electrolyte membrane reinforcing member according to any one of claims 13, 14, or 17.

22. A water electrolysis apparatus having an electrolyte membrane reinforcing member according to any one of claims 13, 14, or 17.

23. A metallized film comprising a biaxially oriented polyarylene sulfide film according to claim 1, wherein a metal layer is provided on at least one side of the polyarylene sulfide film.

24. A current collector foil comprising a biaxially oriented polyarylene sulfide film as described in claim 1, with a metal layer provided on at least one side.

25. A secondary battery comprising the current collector foil described in claim 24.

26. A film capacitor comprising the metallized film described in claim 23.

27. Electrical insulating paper for motors using the biaxially oriented polyarylene sulfide film described in claim 1.

28. A motor using the motor electrical insulating paper described in claim 27.

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