Diaphragm cloth for water electrolysis cell

Abstract

Disclosed in the present invention is a diaphragm cloth for a water electrolysis cell. The diaphragm cloth is a woven fabric formed by high-temperature and acid-alkali resistant long-fiber multifilaments. The linear density of monofilaments in the long fiber multifilaments is 0.01-0.50 dtex, the diaphragm cloth has a maximum pore size of 6.00-30.00 μm, and an average pore size of 2.00-15.00 μm, and the ratio of the maximum pore size to the average pore size is greater than 1.00 and less than 3.00. The diaphragm cloth for a water electrolysis cell of the present invention has the characteristics of high ion permeability and air tightness.

Description

Membrane cloth for water electrolyzer TECHNICAL FIELD

[0001] The present application relates to a kind of membrane cloth for water electrolyzer. BACKGROUND

[0002] In alkaline water electrolyzer, the skilled person uses membrane cloth to block the hydrogen and oxygen generated by cathode and anode, so as to ensure that the gas purity in electrolyzer is high and the operating voltage is low.

[0003] At present, the membrane cloth is formed by the short fiber of high temperature resistant and acid and alkali resistant commonly used at temperature above 150 DEG C, due to the length of short fiber, the uneven arrangement of fiber during spinning, resulting in the surface of the prepared membrane cloth has many hair, the distribution of pore is irregular, and the air tightness is low.If the membrane cloth is used in electrolyzer for a long time, the short fiber will fall off, and the membrane cloth will form light-transmitting holes.In addition, the thickness of short fiber will also affect the performance of the membrane cloth, if the diameter of short fiber is too small, the carding is difficult during spinning, and the defects increase during weaving, resulting in the air tightness of the membrane cloth is poor;if the diameter of short fiber is too large, the specific surface area of the membrane cloth is small, the pore size is large, and the air tightness is poor.

[0004] For example, Chinese patent CN107835873A discloses a kind of high-performance polyphenyl sulfide fiber structure and its manufacturing method and use, and the structure is formed by polyphenyl sulfide short fiber with cross-sectional diameter of 0.1-12 μm.The surface of the woven fabric prepared from polyphenyl sulfide short fiber has many hair, and the friction between the woven fabric and the electrode plate is large, and the bubbles are easy to gather.On the other hand, the maximum pore size of the structure is large, and the average pore size is small, so that the ratio of the maximum pore size to the average pore size is too large, resulting in the pore size of the structure is not uniform, and thus the ion permeability and air tightness are not good.

[0005] For example, Japanese patent 2023-142606 discloses a kind of membrane substrate for water electrolysis, and the substrate is formed by polyphenyl sulfide monofilament with fineness of 3.00-50.00 dtex, since the fineness of monofilament is thick, resulting in the membrane cloth has large void, and the pore size is not uniform, thus the ion permeability and air tightness are poor. SUMMARY

[0006] The purpose of the present application is to provide a kind of membrane cloth for water electrolyzer with high ion permeability and air tightness.

[0007] The technical solution of the present application is as follows: the membrane cloth of the present application is formed by high temperature resistant and acid and alkali resistant long fiber multifilament, the linear density of monofilament in the long fiber multifilament is 0.01-0.50 dtex, the maximum pore size of the membrane cloth is 6.00-30.00 μm, the average pore size is 2.00-15.00 μm, and the ratio of the maximum pore size to the average pore size is greater than 1.00 and less than 3.00.

[0008] The diaphragm cloth of the present application is formed by fine long fiber multifilament, and the ratio of the maximum pore size to the average pore size of the diaphragm cloth is greater than 1.00 and less than 3.00, which ensures that the diaphragm cloth forms uniform pores, so that the diaphragm cloth has the characteristics of high ion permeability and gas tightness. DETAILED DESCRIPTION

[0009] The diaphragm cloth of the present application is a woven fabric formed by long fiber multifilament resistant to high temperature and acid and alkali. The long fiber multifilament is continuous filament, and forms a uniform interlaced structure during weaving, so that the diaphragm cloth has high uniformity of pore distribution, and the long fiber multifilament has no hairiness, so that the surface of the diaphragm cloth is smooth. During operation of the electrolytic cell, the generated bubbles are difficult to adhere to the surface of the diaphragm cloth, and ions are easy to pass through, and the friction between the diaphragm cloth and the electrode plate is small, so that even if the diaphragm cloth is used in the electrolytic cell for a long time, it is not easy to be worn and torn, and the fibers will not be broken, and the diaphragm cloth can maintain the complete structure.

[0010] The long fiber multifilament resistant to high temperature and acid and alkali is preferably long fiber multifilament formed by at least one of polyphenylene sulfide, polytetrafluoroethylene, and polyether ether ketone, and more preferably polyphenylene sulfide long fiber multifilament.

[0011] The diaphragm cloth of the present application is a woven fabric, and has the characteristics of uniform pore size, can block the cross penetration of hydrogen and oxygen, improve the gas purity, and ensure the efficient conduction of ions. In order to make the pores of the woven fabric more uniform and compact, the diaphragm cloth of the present application is preferably plain woven fabric.

[0012] The long fiber multifilament can be obtained by direct spinning, or can be obtained by island-in-sea composite spinning, and the latter is preferred. When island-in-sea composite spinning is adopted, polyphenylene sulfide chips and alkali-soluble polyester are spun to obtain extremely fine island-in-sea composite filament, and the filament is formed by a plurality of filaments. The linear density of the filament is 0.01-0.50 dtex. Within the range, the structure of the obtained woven fabric is compact and the pore size is uniform. If the linear density of the filament is greater than 0.50 dtex, the greater the linear density of the filament, the fewer the number of filaments in the long fiber multifilament, and the greater the gap between the fibers in the long fiber multifilament, which leads to a decrease in the gas tightness of the diaphragm cloth. If the linear density of the filament is less than 0.01 dtex, the strength of the obtained woven fabric is low after weight reduction, and the yarn of the diaphragm cloth is easy to break after friction between the diaphragm cloth and the electrode plate, which leads to a high friction coefficient and low gas tightness of the diaphragm cloth. Considering the low friction coefficient and high gas tightness of the diaphragm cloth, the linear density of the filament is preferably 0.01-0.30 dtex.

[0013] The maximum pore size of the diaphragm cloth is 6.00-30.00 μm, the average pore size is 2.00-15.00 μm, and the ratio of the maximum pore size to the average pore size is greater than 1.00 and less than 3.00. The diaphragm cloth is prepared by direct spinning or island-in-sea composite spinning and then weaving. If the ratio is greater than 3.00, the pore size of the diaphragm cloth is uneven, the pore size is large, and the air tightness is poor. If the ratio is less than 1.00, the ion transmission resistance increases, and the electrolysis efficiency decreases.

[0014] The diaphragm cloth preferably has a maximum pore size of 7.00-20.00 μm, an average pore size of 3.00-10.00 μm, and a ratio of the maximum pore size to the average pore size greater than 1.00 and less than 3.00. The diaphragm cloth is preferably prepared by hydrophilic processing, which includes any one of plasma processing, sulfonation processing, oxidation processing, and hydrophilic resin processing. At this time, the affinity of the fibers in the diaphragm cloth to water is enhanced, water molecules more easily penetrate into the gaps between the fibers, the agglomeration force between the fibers is weakened, and the fibers are more easily dispersed.

[0015] The diaphragm cloth more preferably has a maximum pore size of 7.00-15.00 μm, an average pore size of 3.00-8.00 μm, a ratio of the maximum pore size to the average pore size greater than 1.00 and less than 3.00, and a surface containing a hydrophilic resin. The diaphragm cloth is more preferably prepared by one of plasma processing, sulfonation processing, and oxidation processing and hydrophilic resin processing. In view of the more excellent ion permeability and air tightness, stiffness, and easier installation of the diaphragm cloth, the diaphragm cloth of the present application is further preferably prepared by sulfonation processing and hydrophilic resin processing.

[0016] The hydrophilic processing makes the fiber surface of the diaphragm cloth contain a hydrophilic group. Specifically, the hydrophilic group is carboxyl and hydroxyl after plasma processing, sulfonic acid group after sulfonation processing, carboxyl or phosphoric acid group after oxidation processing, and hydroxyl after hydrophilic resin processing. The hydrophilic group can improve the wettability of the diaphragm cloth to the electrolyte, make the electrolyte quickly fill the pores of the diaphragm cloth, ensure the stability of ion conduction, and improve the electrolysis efficiency. The fiber surface of the diaphragm cloth more preferably contains sulfonic acid group and hydroxyl.

[0017] The sulfonation processing preferably involves sulfonation treatment of the diaphragm cloth in a mixed solution of sulfuric acid and chromic acid at a certain temperature and time.

[0018] The oxidation processing refers to oxidation treatment of the diaphragm cloth in a solution of a strong oxidizing agent at a certain concentration, temperature, and time. The strong oxidizing agent includes potassium permanganate, hydrogen peroxide, or nitric acid.

[0019] The hydrophilic resin processing refers to resin impregnation processing of the separator cloth, so as to improve the stiffness of the separator cloth. The bending length is used to represent the stiffness of the separator cloth and the installation difficulty. The smaller the bending length is, the softer the separator cloth is, and the more likely to cause wrinkles in the process of assembly, the ion transmission path increases, resulting in the increase of the resistance of the separator cloth. The larger the bending length is, the stiffer the separator cloth is, and the more difficult to bend and deform, and the easier to install. Considering the stiffness of the separator cloth and the installation difficulty, the bending length of the separator cloth is preferably 40.00-90.00 mm, and more preferably 70.00-90.00 mm.

[0020] The hydrophilic resin is preferably polyvinyl alcohol or polyethylene glycol resin. In addition, the concentration of the hydrophilic resin also has requirements in the process of resin impregnation. If the concentration of the hydrophilic resin is too large, the excess resin penetrates into the fiber, which increases the brittleness of the separator cloth, and the separator cloth may be damaged by the impact of the alkaline solution. In addition, the excess resin is easy to cause the fiber to shrink and agglomerate, and the local part of the separator cloth will form a large pore structure, the pore size distribution is uneven, the ion transmission path distribution is uneven when the electrolyte passes through the separator cloth, resulting in the increase of the resistance of the separator cloth. If the concentration of the hydrophilic resin is too low, the pores of the separator cloth cannot be uniformly filled, and the gas is easy to pass through the large pores, and the air tightness is reduced. In order to balance the ion permeability and air tightness of the separator cloth, the more preferred concentration of the polyvinyl alcohol resin is 3-8%.

[0021] The distance from the lowest point to the highest point on the surface of the separator cloth of the present application is 100-400 μm, which is related to the bending wave height of the warp and weft yarns of the fabric. The lowest point refers to the intersection point of the warp and weft yarns, and the highest point refers to the bending height of the surface yarns. Generally, for the fabrics with the same thickness of warp and weft yarns, the warp yarns appear on the surface when the warp density is large, and the weft yarns appear on the surface when the weft density is large. The present application preferably uses the warp yarns to appear on the surface, i.e. the highest point is the bending height of the warp yarns. The distance from the lowest point to the highest point on the surface of the separator cloth forms the surface concave-convex, which affects the resistance of the bubbles attached to the surface of the separator cloth to detach during electrolysis, i.e. affects the size of the bubble floating angle. The smaller the bubble floating angle is, the easier the bubbles are to detach from the surface of the separator cloth, and the better the operation of the electrolytic cell is. If the distance is too small, the bending wave height of the warp yarns is too small, and the multifilament is thin and flat, so the thickness of the obtained separator cloth is thin, and the air tightness is low. If the distance is too large, the surface of the fabric is concave-convex, the bubbles are attached to the separator cloth, the resistance of the separator cloth surface increases, and the yarns protruding on the surface are easy to rub against the electrode plate, so the service life of the separator cloth is reduced.

[0022] The number of monofilaments in the long fiber multifilament is preferably 200 or more, and more preferably 200 to 10,000. When the fineness of the long fiber multifilament is the same, the more the number of monofilaments, the smaller the linear density of the monofilament, the thinner the monofilament, the higher the specific surface area of the diaphragm cloth, the larger the reaction area during hydrophilic modification, the better the hydrophilicity of the diaphragm cloth, the better the interfacial bonding with the solution in the electrolytic cell, and the bubbles are not easy to adhere or enter the inside of the diaphragm, and the ions are easy to pass through. Moreover, the thinner the monofilament, the smaller the gap between the monofilaments, and the higher the air tightness of the diaphragm cloth.

[0023] The specific surface area of the diaphragm cloth of the present application is preferably 0.40 to 3.10 m 2 / g, and more preferably 1.00 to 3.10 m 2 / g. If it is too small, it means that the linear density of the monofilament is too large, and in the electrolytic cell, bubbles are easy to enter the inside of the diaphragm cloth, hinder the passage of ions, increase the resistance of the diaphragm cloth surface, and have low air tightness. If it is too large, the surface of the diaphragm cloth is rough, and hair and defects are easy to occur during friction, affecting the gas purity and safety of the electrolytic cell.

[0024] The thickness of the diaphragm cloth of the present application is preferably 0.50 mm or less. If it is too thick, the path of ion passage increases, and the resistance of the diaphragm cloth becomes high. If it is too thin, the puncture resistance and wear resistance of the diaphragm cloth tend to deteriorate, and bubbles are more likely to pass through, resulting in low air tightness. Considering the low resistance and high air tightness of the diaphragm cloth, the thickness of the diaphragm cloth is more preferably 0.10 to 0.40 mm.

[0025] The dynamic friction average coefficient of the diaphragm cloth of the present application is preferably 0.500 or less, indicating that the surface of the diaphragm cloth is flat and the friction between the diaphragm cloth and the polar plate is small, which is beneficial to the operation of the electrolytic cell.

[0026] The mass loss of the diaphragm cloth of the present application after 5000 rubs is preferably 20 mg or less, indicating that during the operation of the electrolytic cell, the scouring of the lye makes the friction between the diaphragm cloth and the polar plate small, and the electrolytic cell runs safely.

[0027] In order to make the bubbles more easily detach from the surface of the electrode or diaphragm cloth, the floating angle of the diaphragm cloth of the present application is preferably 2 to 15°. The floating angle refers to the angle formed between the bubble and the surface of the diaphragm cloth. If the floating angle is too large, the bubbles are retained on the diaphragm cloth, resulting in an increase in the resistance of the diaphragm cloth.

[0028] The resistance of the diaphragm cloth of the present application after durability treatment is maintained at 6.00 to 15.00 mΩ, and the air tightness is maintained at 700 mmH2O or more. The durability treatment here refers to treatment in a 30% concentration KOH solution at a temperature of 60 to 120°C for one month, and the temperature is set according to the use environment of the diaphragm cloth in the electrolytic cell.

[0029] The present application is further illustrated by the following examples, but the scope of the present application is not limited to the examples, and each property in the examples is measured by the following method.

[0030]

Maximum pore size of the membrane fabric

[0031] The pore size of the membrane fabric is measured according to the standard of ASTM F316-03 by using a Capillary Flow Porometer (PMI product, model: CFP-1100-AX), and the working mode is set as wet-up / dry-up mode. The sample is placed in the sample chamber and is infiltrated with a Galwick solution having a surface tension of 15.9 dynes / cm. The bottom clamp of the sample chamber has a porous metal disc insert with a diameter of 2.54 cm and a thickness of 3.175 mm, and the top clamp of the sample chamber has a hole with a diameter of 3.175 mm, and the value of the maximum pore size of the membrane fabric can be directly read out. The average value of two measurements is taken as the final maximum pore size value.

[0032]

Average pore size of the membrane fabric

[0033] The pore size of the membrane fabric is measured according to the standard of ASTM F316-03 by using a Capillary Flow Porometer (PMI product, model: CFP-1100-AX), and the working mode is set as wet-up / dry-up mode. The sample is placed in the sample chamber and is infiltrated with a Galwick solution having a surface tension of 15.9 dynes / cm. The bottom clamp of the sample chamber has a porous metal disc insert with a diameter of 2.54 cm and a thickness of 3.175 mm, and the top clamp of the sample chamber has a hole with a diameter of 3.175 mm, and the value of the average pore size of the membrane fabric can be directly read out. The average value of two measurements is taken as the final average pore size value.

[0034]

Distance from the lowest point to the highest point on the surface of the membrane fabric

[0035] Five 10 cm x 10 cm flat and wrinkle-free membrane fabric samples are cut, and one sample is placed under a VHK-6000 digital microscope, and a 3D photo of an arbitrary place on the sample is randomly taken at a magnification of 50 times, and the device automatically identifies and measures the distance S from the lowest point to the highest point on the surface of the membrane fabric. Z Then, the other four membrane fabric samples are taken, and finally the average value is taken.

[0036]

Linear density of the monofilament

[0037] Take a piece of diaphragm cloth, and take its warp and weft yarns along the warp and weft directions respectively. Measure the length L (such as 9 cm) of the warp and weft yarns, and weigh each fiber with a torsion balance to obtain the linear density T = (X x 10000 / L) of the multifilament. Take 10 of each of the warp and weft directions, and take their average. Then, embed the warp and weft yarns in wool fibers respectively, cut the cross section of the yarns by passing through a copper plate hole, and take a picture of the cross section of the yarns using a digital microscope at a magnification of 50-200 times. Count the number of filaments N directly from the picture. d

[0038]

Number of filaments

[0039] Take a piece of diaphragm cloth, and take its warp and weft yarns along the warp and weft directions respectively. Embed the warp and weft yarns in wool fibers respectively using the embedding method, cut the cross section of the yarns by passing through a copper plate hole, and take a picture of the cross section of the yarns using a digital microscope at a magnification of 50-200 times. Count the number of filaments N directly from the picture.

[0040]

Specific surface area of diaphragm cloth

[0041] Mark a certain distance along the warp direction on the diaphragm cloth, denoted as L0. Then, take out the warp yarns marked with the mark from the fabric, and stretch the yarns under the action of a tension of 0.1 g / dtex. Measure the length between two points, denoted as L1. The calculation formula of the buckling rate of the yarns is a = (L1-L0) / L0 x 100%. The diameter of the filaments is obtained by the following calculation formula: (wherein, T: linear density of filaments, p: density of yarns). The calculation formula of the specific surface area S of the diaphragm cloth is as follows:

[0042] S = 2 x (1 x a + d / 2) / [p x 1 x a x (d / 2)].

[0043]

Hydrophilic group component

[0044] The X-ray photoelectron spectrometer (product of Thermo Company, Germany, instrument model: ESCALAB 250Xi) is used to qualitatively and quantitatively analyze the chemical composition of the fiber surface. The oxygen element content is calculated according to the X-ray photoelectron spectrum, the peaks are separated, and the corresponding peak values are determined to determine the hydrophilic group component.

[0045]

Hydrophilic resin component

[0046] ​The infrared spectrophotometer (model: IRTracer-100, manufacturer: Shimadzu) is used to qualitatively and quantitatively analyze the composition of the fiber surface hydrophilic resin. The characteristic absorption peak of the sample is obtained by scanning the infrared spectrophotometer, the spectrum is processed according to the position and intensity of the characteristic peak, and the composition of the hydrophilic resin is determined according to the relative content of the functional group absorption.

[0047]

Thickness

[0048] According to JIS L1096 8.4.3 standard, cut 3 samples of 20cm x 20cm under standard conditions, use thickness gauge (model THC-3ND, pressure 240gf / cm 2 ) to measure the thickness of the middle of each sample, and take the average value.

[0049]

Grammage

[0050] According to JIS L1096-1999 8.4 standard, use an electronic balance to weigh a 10cm x 10cm sample, then multiply the resulting data by 100 to get the weight of the converted per square meter of membrane cloth.

[0051]

Density

[0052] According to JIS L1096 8.6 density method, use a densimeter to measure the warp and weft density of the membrane cloth.

[0053]

Dynamic friction average coefficient

[0054] Cut the membrane cloth with a size of 20cm x 20cm, use KES-FB4 surface performance tester to test the dynamic friction average coefficient (MIU) of the membrane cloth, select a 1cm x 1cm metal friction head, pressure 50cN, sliding speed 60mm / min speed friction, obtain the dynamic friction coefficient, at least 3 samples per group, take the average value.

[0055]

Weight loss after friction 5000 times

[0056] According to GB / T 21196.3-2007 Textiles Determination of the mass loss of the abrasion resistance of fabrics by the Martin's method Part 3 Determination of the mass loss.

[0057]

Floating angle

[0058] Paste the membrane cloth sample on the bottom plate and put it into a water tank filled with water, inject 10μL bubbles with a syringe needle, make them adhere to the surface of the membrane cloth sample, tilt the water tank at a speed of 0.5° / s, observe the shape and position of the bubbles with a camera, when the bubbles start to float, measure the tilt angle at this time, which is the floating angle.

[0059]

Air tightness

[0060] According to the air tightness test method of Chinese building material industry standard JCT 211-2009 "Diaphragm asbestos cloth" standard 4.5.2, the sample size of the experimental sample is 20 cm x 20 cm, the sample is soaked in water for 30 minutes, after it is completely soaked, the sample is installed flat on the test equipment, ensuring that it is sealed and does not leak water, water is added above the sample to 10 cm from the cloth surface, and the water surface is observed, when the bubbles start to appear, the air tightness test value at this time is recorded, at least 3 pieces of sample per group, and the average value is taken.

[0061]

Resistance

[0062] First, the internal resistance tester (Shanghai Genggeng Instrument and Equipment Co., Ltd., Model: DC0506) containing a 30wt% concentration of potassium hydroxide solution is placed in a low temperature constant temperature tank control device and heated to 60°C, and the blank resistance R0 is measured. Then the diaphragm cloth is installed in the clamp of the battery internal resistance tester (Changzhou Anbo Precision Instrument Co., Ltd., Model: AT526), and the test resistance R1 is measured. The calculation formula of the resistance R of the diaphragm cloth is as follows: R = R1-R0, and 5 tests are performed respectively, and the average value is taken.

[0063]

Bending length

[0064] According to JIS L-1096:2010 A method (cantilever method), NP-37 stiffness tester is used, diaphragm cloth sample with size of 2 cm x 15 cm is taken, the sample is placed on the tester, the slide plate of the tester is pushed at a slow and uniform speed, when the front end of the sample touches the slope of the tester, the slide plate is immediately stopped, then the length of the push is measured, which is the bending length of the diaphragm cloth, and 5 samples per group are taken, and the average value is taken.

[0065]

Ease of installation

[0066] According to the average value of the bending length of the sample, the ease of installation of the diaphragm cloth in the electrolytic cell is divided, when the bending length is 1.00 mm to 20.00 mm, the diaphragm cloth is difficult to install and cannot be installed, which is represented as x; when the bending length is greater than 20.00 mm and less than 70.00 mm, the ease of installation of the diaphragm cloth is moderate, which is represented as Δ; when the bending length is 70.00 mm to 90.00 mm, the installation of the diaphragm cloth is excellent, which is represented as O.

[0067] Example 1

[0068] A 70 wt% polyphenylene sulfide chip and a 30 wt% alkali-soluble polyester were extruded from a spinneret having 24 holes and 37 islands per hole at 300°C using a bicomponent spinning machine by island-in-the-sea spinning technology, and then extended to produce island-in-the-sea long fiber multifilament. The long fiber multifilament was woven as warp and weft to produce a plain weave fabric having a warp density of 120 threads / inch and a weft density of 74 threads / inch. The produced fabric was then subjected to weight reduction treatment in a 30 g / L sodium hydroxide solution at 125°C for 60 minutes to remove the alkali-soluble polyester component, and then washed with water and heat set to produce a woven fabric having a single filament linear density of 0.08 dtex. The produced woven fabric was then subjected to sulfonation treatment in a mixed solution of 490 g / L sulfuric acid and 280 g / L chromic acid at 80°C for 10 minutes, and then dipped in a 5% polyvinyl alcohol resin aqueous solution, followed by roller and heat setting to finally produce the separator fabric of the present application. The separator fabric was measured to have a maximum pore diameter of 9.98 μm, an average pore diameter of 5.10 μm, and a ratio of the maximum pore diameter to the average pore diameter of 1.96.

[0069] Examples 2 to 6

[0070] The production process was the same as in Example 1, and the specific formulation and properties are shown in Table 1.

[0071] Example 7

[0072] The production process of the woven fabric was the same as in Example 1. The produced woven fabric was subjected to sulfonation treatment in a mixed solution of 490 g / L sulfuric acid and 280 g / L chromic acid at 80°C for 10 minutes, and then subjected to reduction washing and heat setting to finally produce the separator fabric of the present application. The separator fabric was measured to have a maximum pore diameter of 11.50 μm, an average pore diameter of 5.60 μm, and a ratio of the maximum pore diameter to the average pore diameter of 2.05. The specific formulation and properties are shown in Table 2.

[0073] Example 8

[0074] The production process of the woven fabric was the same as in Example 1. The produced woven fabric was dipped in a 5% polyvinyl alcohol resin aqueous solution, followed by roller and heat setting to finally produce the separator fabric of the present application. The separator fabric was measured to have a maximum pore diameter of 19.70 μm, an average pore diameter of 9.80 μm, and a ratio of the maximum pore diameter to the average pore diameter of 2.01. The specific formulation and properties are shown in Table 2.

[0075] Example 9

[0076] The woven fabric was prepared according to the process of Example 1. The prepared woven fabric was subjected to oxidation treatment in a potassium permanganate solution with a concentration of 5%, at a temperature of 80°C for 10 minutes, and then subjected to reduction washing and heat setting to obtain the separator fabric of the present application. The maximum pore size of the separator fabric was measured to be 15.00 μm, the average pore size was 6.20 μm, and the ratio of the maximum pore size to the average pore size was 2.42. The specific formulation and physical properties are shown in Table 2.

[0077] Example 10

[0078] The polyphenylene sulfide chips were converted into polyphenylene sulfide melt at 300°C, and continuous polyphenylene sulfide fiber filaments were prepared by using the electrospinning technique through the distribution plate of the spinneret. After stretching, long fiber multifilaments with a linear density of 0.08 dtex were obtained. The long fiber multifilaments were used as warp and weft yarns to weave a plain woven fabric with a warp density of 120 threads / inch and a weft density of 74 threads / inch. The prepared woven fabric was subjected to scouring, washing, drying, and then sulfonated treatment in a mixed solution of sulfuric acid with a concentration of 490 g / L and chromic acid with a concentration of 280 g / L, at a temperature of 80°C for 10 minutes. The prepared woven fabric was then subjected to reduction washing and heat setting to obtain the separator fabric of the present application. The maximum pore size of the separator fabric was measured to be 13.67 μm, the average pore size was 4.98 μm, and the ratio of the maximum pore size to the average pore size was 2.74. The specific formulation and physical properties are shown in Table 2.

[0079] Example 11

[0080] The woven fabric was prepared according to the process of Example 1. The prepared woven fabric was subjected to oxidation treatment in a potassium permanganate solution with a concentration of 5%, at a temperature of 80°C for 10 minutes, and then subjected to reduction washing and heat setting to obtain the separator fabric of the present application. The maximum pore size of the separator fabric was measured to be 15.00 μm, the average pore size was 6.20 μm, and the ratio of the maximum pore size to the average pore size was 2.42. The specific formulation and physical properties are shown in Table 2.

[0081] Example 12

[0082] The woven fabric was prepared according to the process of Example 1. The prepared woven fabric was subjected to oxidation treatment in a potassium permanganate solution with a concentration of 5%, at a temperature of 80°C for 10 minutes, and then immersed in a polyvinyl alcohol resin aqueous solution with a concentration of 5%. The fabric was then subjected to roller treatment and heat setting to obtain the separator fabric of the present application. The maximum pore size of the separator fabric was measured to be 14.30 μm, the average pore size was 6.80 μm, and the ratio of the maximum pore size to the average pore size was 2.10. The specific formulation and physical properties are shown in Table 2.

[0083] Comparative Example 1

[0084] A 70 wt% polyphenylene sulfide chip and 30 wt% alkali-soluble polyester were extruded at 300°C from a spinneret having 50 holes and 1 island per hole using an island-in-the-sea spinning technique, and then extended to produce island-in-the-sea long fiber multifilaments. The long fiber multifilaments were woven as warp and weft yarns to produce a plain weave fabric having a warp density of 120 ends / inch and a weft density of 78 ends / inch. The resulting fabric was then subjected to weight reduction treatment in a 30 g / L sodium hydroxide solution at 125°C for 60 minutes to remove the alkali-soluble polyester component, and then washed and heat set to produce a woven fabric having a linear density of 3.00 dtex. The resulting woven fabric was subjected to sulfonation treatment in a mixed solution of sulfuric acid and chromic acid to produce a polyphenylene sulfide separator fabric having a maximum pore diameter of 26.50 μm, an average pore diameter of 6.20 μm, and a ratio of maximum pore diameter to average pore diameter of 4.27. The physical properties of the polyphenylene sulfide separator fabric are shown in Table 3.

[0085] Comparative Example 2

[0086] Polyphenylene sulfide staple fibers having a linear density of 0.9 dtex and a length of 51 mm were spun using a cotton spinning process including scutching, carding, drawing, roving, spinning, winding, doubling, twisting, and heat setting to produce a 40S short fiber yarn. The short fiber yarn was woven as warp and weft yarns to produce a plain weave fabric having a warp density of 118 ends / inch and a weft density of 79 ends / inch. The resulting fabric was then subjected to scouring, washing, and drying, and then the heat-dried fabric was subjected to sulfonation treatment in a mixed solution of sulfuric acid and chromic acid. A polyphenylene sulfide separator fabric having a maximum pore diameter of 42.60 μm, an average pore diameter of 6.90 μm, and a ratio of maximum pore diameter to average pore diameter of 6.17 was produced. The physical properties of the polyphenylene sulfide separator fabric are shown in Table 3.

[0087] Table 1

[0088] Table 2

[0089] Table 3

[0090] From the above table,

[0091] (1) As can be seen from Examples 1 and 2, under the same conditions, the long fiber multifilament of the former is a PPS long fiber multifilament, and the long fiber multifilament of the latter is a PEEK long fiber multifilament. Compared with the latter, the ratio of maximum pore diameter to average pore diameter of the separator fabric of the former is smaller, i.e., the pore diameter distribution of the separator fabric is more uniform, the ion permeability is higher, and the gas tightness is higher.

[0092] (2) From Example 1 and Example 4, under the same conditions, the specific surface area of the separator cloth in the former is in the more preferable range, and compared with the latter, the gas tightness of the separator cloth obtained in the former is high and the resistance is small.

[0093] (3) From Example 1 and Example 5, under the same conditions, the linear density of the monofilament in the former is in the preferable range, and compared with the latter, the gas tightness of the separator cloth obtained in the former is high and the resistance is small.

[0094] (4) From Example 1 and Example 6, under the same conditions, the concentration of the polyvinyl alcohol resin in the former is in the more preferable range, and compared with the latter, the ratio of the maximum pore size to the average pore size of the separator cloth obtained in the former is small, that is, the pore size distribution of the separator cloth is more uniform, the ion permeability is high, and the gas tightness is high.

[0095] (5) From Example 1 and Example 7, under the same conditions, the separator cloth in the former is prepared by sulfonation processing and polyvinyl alcohol resin processing, and the separator cloth in the latter is prepared by sulfonation processing, and compared with the latter, the gas tightness of the separator cloth obtained in the former is high, the bending length is long, and the installation performance is excellent.

[0096] (6) From Example 7 and Example 11, under the same conditions, the separator cloth in the former is subjected to sulfonation processing, and the separator cloth in the latter is not subjected to hydrophilic processing, and compared with the latter, the ratio of the maximum pore size to the average pore size of the separator cloth obtained in the former is small, that is, the pore size distribution of the separator cloth is more uniform, the ion permeability is high, and the gas tightness is high.

[0097] (7) From Example 1 and Example 12, under the same conditions, the separator cloth in the former is prepared by sulfonation processing and polyvinyl alcohol resin processing, and compared with the latter, the ratio of the maximum pore size to the average pore size of the separator cloth obtained in the former is small, that is, the pore size distribution of the separator cloth is more uniform, the ion permeability is high, and the gas tightness is high.

[0098] (8) From Example 7 and Comparative Example 1, under the same conditions, the linear density of the monofilament in the latter is too large, and compared with the former, the gas tightness of the separator cloth obtained in the latter is low and the resistance is high.

[0099] (9) From Example 7 and Comparative Example 2, under the same conditions, the separator cloth in the latter is composed of short fibers, and compared with the former, the gas tightness of the separator cloth obtained in the latter is low.

Claims

1. A separator cloth for a water electrolyzer, characterized by: The diaphragm cloth is a woven fabric formed of high-temperature-resistant and acid-alkali-resistant long fiber filaments, the linear density of the filaments in the long fiber filaments is 0.01-0.50 dtex, the maximum pore size of the diaphragm cloth is 6.00-30.00 μm, the average pore size is 2.00-15.00 μm, and the ratio of the maximum pore size to the average pore size is greater than 1.00 and less than 3.

00.

2. The separator fabric for a water electrolyzer according to claim 1, characterized by: The maximum pore size of the diaphragm cloth is 7.00-20.00 μm, the average pore size is 3.00-10.00 μm, and the ratio of the maximum pore size to the average pore size is greater than 1.00 and less than 3.

00.

3. The separator fabric for a water electrolyzer according to claim 2, characterized by: The maximum pore size of the diaphragm cloth is 7.00-15.00 μm, the average pore size is 3.00-8.00 μm, the ratio of the maximum pore size to the average pore size is greater than 1.00 and less than 3.00, and the surface of the diaphragm cloth contains a hydrophilic resin.

4. The separator fabric for a water electrolyzer according to claim 1, characterized by: The distance from the lowest point to the highest point on the surface of the diaphragm cloth is 100-400 μm.

5. The separator fabric for a water electrolyzer according to claim 1, characterized by: The number of filaments in the long fiber filaments is 200 or more.

6. The separator fabric for a water electrolyzer according to claim 1, characterized by: The specific surface area of the said membrane cloth is 0.40-3.10 m 2 / g.

7. The separator fabric for a water electrolyzer according to claim 1, characterized by: The thickness of the diaphragm cloth is 0.50 mm or less.

8. The separator fabric for a water electrolyzer according to claim 1, characterized by: The high-temperature-resistant and acid-alkali-resistant long fiber filaments are long fiber filaments formed of at least one of polyphenylene sulfide, polytetrafluoroethylene, and polyether ether ketone.

9. The separator fabric for a water electrolyzer according to claim 3, characterized by: The hydrophilic resin is a polyvinyl alcohol resin or a polyethylene glycol resin.

10. The separator fabric for a water electrolyzer according to claim 2, characterized by: The surface of the fibers of the diaphragm cloth contains a hydrophilic group, and the hydrophilic group is at least one of a carboxyl group, a sulfonic acid group, a hydroxyl group, and a phosphoric acid group.

11. The separator fabric for a water electrolyzer according to claim 10, characterized by: The hydrophilic group is a sulfonic acid group and a hydroxyl group.

12. The separator fabric for a water electrolyzer according to claim 1, characterized by: The kinetic friction average coefficient of the diaphragm cloth is 0.500 or less.

13. The separator fabric for a water electrolyzer according to claim 1, characterized by: The mass loss of the diaphragm cloth after 5000 rubs is 20.0 mg or less.

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