PEEK fine denier monofilament spinning process for proton exchange membrane of PEM electrolyzer and PEEK fine denier monofilament prepared by the spinning process

Abstract

The application discloses a spinning process of PEEK fine denier monofilament for a proton exchange membrane of a PEM electrolytic cell, and comprises the following steps: S1, drying PEEK resin chips; S2, adding the dried PEEK resin chips into a screw extruder for melt extrusion, the temperature range of a compression section is 390-450 DEG C, and the temperature range of a metering section is 390-440 DEG C; S3, filtering the PEEK melt extruded from the screw extruder through a filter screen group and then through a layer of metal sand, and then entering a spinneret, and then being sprayed from the spinneret to form a plurality of nascent monofilaments; the spinneret hole of the spinneret is composed of an upper segment spinneret guide hole and a lower segment spinneret micro-hole, and the length-diameter ratio of the spinneret micro-hole of the spinneret hole is 8-10; S4, collecting the nascent monofilaments after cooling to form nascent multifilaments; and S5, forming PEEK fine denier monofilaments by stretching, setting, winding and separating the nascent multifilaments. The application has the advantage that PEEK fine denier monofilaments with a fiber diameter less than 25 microns can be prepared.

Description

Technical Field

[0001] This invention relates to the field of PEM electrolysis technology, specifically to the spinning process of PEEK fine denier monofilaments for proton exchange membranes in PEM electrolysis cells and the PEEK fine denier monofilaments obtained by the spinning process. Background Technology

[0002] Hydrogen energy, as an efficient, clean, and ideal secondary energy source, has received widespread attention worldwide. Large-scale, inexpensive hydrogen production is a crucial aspect of its development and utilization. Using green electricity and water electrolysis to produce H2 can achieve a zero-carbon process, aligning with national development strategies, and is relatively simple to operate with mature technology.

[0003] Depending on the membrane material of the electrolyzer, the industry generally classifies water electrolysis for hydrogen production into alkaline water electrolysis (ALK), proton exchange membrane water electrolysis (PEM), and high-temperature solid oxide water electrolysis (SOEC).

[0004] Compared with alkaline water electrolysis hydrogen production technology, PEM water electrolysis hydrogen production technology has the advantages of high current density, high hydrogen purity, fast response speed, and high working efficiency. PEM water electrolysis hydrogen production uses a proton exchange membrane as a solid electrolyte and pure water as a raw material. Under the action of direct current, an oxidation reaction occurs at the anode to produce oxygen, and a reduction reaction occurs at the cathode to produce hydrogen.

[0005] The proton exchange membrane is the core component of PEM water electrolysis for hydrogen production. The proton exchange membrane is generally composed of a substrate and a perfluorosulfonic acid resin coated on the surface of the substrate. Currently, expanded polytetrafluoroethylene (ePTFE) is commonly used as the substrate. However, due to the poor rigidity and softness of ePTFE, the proton exchange membrane made from it has too much ductility, unstable dimensions, and is prone to cracking and failure.

[0006] To obtain proton exchange membranes with high mechanical strength and dimensional stability, people use polyetheretherketone (PEEK) monofilaments as the substrate for the proton exchange membrane. However, the diameter of the PEEK monofilaments currently used is relatively large, generally above 40 μm, which makes the substrate made of PEEK monofilaments thicker, resulting in a thicker proton exchange membrane. The increase in the thickness of the proton exchange membrane will reduce proton conductivity, increase the internal resistance of the electrolyzer, reduce the current density, and increase the decomposition voltage, thereby affecting the electrolysis efficiency of PEM water electrolysis for hydrogen production. Summary of the Invention

[0007] The purpose of this invention is to provide a spinning process for PEEK fine denier monofilaments with a fiber diameter of less than 25 μm for use in PEM electrolytic cell proton exchange membranes.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a PEEK fine denier monofilament spinning process for PEM electrolytic cell proton exchange membranes, comprising the following steps:

[0009] S1: PEEK resin is sliced ​​and dried;

[0010] S2: The dried PEEK resin chips are added to a screw extruder for melt extrusion. The temperature range of the feed section of the screw extruder is 330-380℃, the temperature range of the compression section is 390-450℃, and the temperature range of the metering section is 390-440℃.

[0011] S3: The PEEK melt extruded by the screw extruder is first filtered through a filter screen group. After filtration, the PEEK melt passes through a layer of metal sand and then enters the spinneret. It is then ejected from the spinneret holes to form several nascent monofilaments. Throughout the entire process of S3, the temperature of the PEEK melt is maintained at 390-440℃.

[0012] The filter screen assembly consists of filter screens with a mesh size of 1600 to 2000, and the metal sand layer consists of metal sand with a mesh size of 16 to 40. The spinneret's spinneret holes consist of an upper spinneret guide hole and a lower spinneret micro-hole, and the aspect ratio of the spinneret micro-holes is 8 to 10.

[0013] S4: After cooling the nascent monofilaments, oil them and bundle them together to form nascent multifilaments;

[0014] S5: The nascent multifilament is stretched, shaped, and wound before being separated into fine denier PEEK monofilaments with a fiber diameter of less than 25μm. The stretching of the nascent multifilament is a two-stage stretching process. The first stage stretching is completed by a primary stretching hot roller with a roller temperature of 160–210℃ and a roller speed of 300–400m / min. The second stage stretching is completed by a secondary stretching hot roller with a roller temperature of 180–240℃ and a roller speed of 800–1200m / min. The stretching ratio between the secondary and primary stretching hot rollers is 2–4. The shaped multifilament is shaped by a shaped hot roller with a roller temperature of 180–240℃ and a roller speed of 700–1100m / min.

[0015] Furthermore, the aforementioned PEM electrolytic cell proton exchange membrane uses a PEEK fine denier monofilament spinning process, wherein: in S3, the filter group includes three layers of filtration, each layer of filtration is composed of filter screens with a mesh size of 1600 to 2000 meshes stacked together, and the three layers of filtration are progressively denser along the PEEK melt flow direction.

[0016] Furthermore, in the aforementioned PEM electrolytic cell proton exchange membrane using PEEK fine denier monofilament spinning process, in the three-layer filter assembly along the PEEK melt flow direction, the first layer is composed of 1600 mesh filter sheets stacked together, the second layer is composed of 1800 mesh filter sheets stacked together, and the third layer is composed of 2000 mesh filter sheets stacked together.

[0017] Furthermore, the aforementioned PEM electrolytic cell proton exchange membrane uses a PEEK fine denier monofilament spinning process, wherein the thickness of the metal sand layer is 1 cm.

[0018] Furthermore, in the aforementioned PEM electrolytic cell proton exchange membrane using PEEK fine denier monofilament spinning process, wherein: in S3, the aspect ratio of the spinneret micro-orifice is 9.

[0019] Furthermore, in the aforementioned PEEK fine denier monofilament spinning process for the PEM electrolytic cell proton exchange membrane, in S5, the stretching of the nascent multifilament is a two-stage stretching process. The first stage stretching is completed by a primary stretching hot roller with a roller temperature of 210°C and a roller speed of 400 m / min, and the nascent multifilament's residence time on the primary stretching hot roller is 0.4 seconds. The second stage stretching is completed by a secondary stretching hot roller with a roller temperature of 240°C and a roller speed of 1100 m / min, and the nascent multifilament's residence time on the secondary stretching hot roller is 0.2 seconds. The stretching ratio between the secondary and primary stretching hot rollers is 4. The shaping of the nascent multifilament is completed by a shaping hot roller with a roller temperature of 240°C and a roller speed of 1100 m / min, and the nascent multifilament's residence time on the tertiary shaping hot roller is 0.2 seconds.

[0020] The second objective of this invention is to provide a PEEK fine denier monofilament for a PEM electrolytic cell proton exchange membrane with a fiber diameter of less than 25 μm.

[0021] Through the implementation of the above technical solutions, the beneficial effects of the present invention are as follows: The entire spinning process is designed, (1) in the PEEK melt extrusion process, the temperature of the screw extruder feed end, compression section and metering section is designed, the temperature of the compression section and metering section is increased, the fluidity of the PEEK melt is further improved, the viscosity of the PEEK melt is smaller, and the monofilament spun from the PEEK melt is easier to stretch and refine in the subsequent process, which provides further assurance for producing fine denier PEEK monofilaments with a fiber diameter of less than 25μm; (2) in the spinneret spinning process, a 1600-2000 mesh filter screen is first used to filter the PEEK melt, effectively filtering out impurities in the PEEK melt, which can not only increase the spinning efficiency of the PEEK melt through the spinneret spinning process, but also improve the fluidity of the PEEK melt. The stability of the PEEK filament during spinning is improved, and the PEEK filament is less prone to breakage during subsequent stretching. This makes the PEEK filament easier to stretch and refine, providing further assurance for producing fine PEEK filaments with a fiber diameter of less than 25μm. (3) In the spinneret spinning process, the filtered PEEK melt needs to pass through a layer of metal sand before entering the spinneret. The metal sand layer can keep the PEEK melt pressure and flow rate uniform, further increasing the stability of the PEEK melt during spinneret spinning, further improving the performance of the spun PEEK filament, making the PEEK filament less prone to breakage during subsequent stretching, and making the PEEK filament easier to stretch and refine, providing further assurance for producing fine PEEK filaments with a fiber diameter of less than 25μm. (4) In the spinneret spinning process, the aspect ratio of the spinneret micro-orifices is designed to be 8-10. This aspect ratio design can effectively reduce the extrusion swelling effect, effectively eliminate the unstable flow of the melt, increase the stability of the PEEK melt when spinning through the spinneret, make the PEEK monofilament less prone to breakage during subsequent stretching, and make the PEEK monofilament easier to stretch and refine in subsequent stages, thus providing further assurance for producing fine denier PEEK monofilaments with a fiber diameter of less than 25μm. On the other hand, the spun PEEK monofilaments are finer, so the PEEK monofilaments are initially refined so that they can be further refined in subsequent stretching, thus providing further assurance for producing fine denier PEEK monofilaments with a fiber diameter of less than 25μm. Further guarantees; (5) In the stretching and shaping process, the roller temperature, roller speed, residence time and stretching ratio of each level of stretching hot roller and shaping roller were designed to ensure that the PEEK fine denier monofilament is stretched to a fiber diameter of less than 25μm, and that the performance of the stretched PEEK fine denier monofilament can meet the requirements for the preparation of water electrolysis hydrogen production membrane; (6) PEEK fine denier monofilament with a fiber diameter of less than 25μm can be obtained. The substrate made by the PEEK fine denier monofilament of this invention is thinner than the traditional substrate, so that the proton exchange membrane made is also thinner. The reduction in the thickness of the proton exchange membrane will improve the proton conductivity, reduce the internal resistance of the electrolytic cell, increase the current density, reduce the decomposition voltage, thereby improving the electrolysis efficiency of PEM water electrolysis hydrogen production. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the spinneret orifice structure in the PEEK fine denier monofilament spinning process for the PEM electrolytic cell proton exchange membrane described in this invention.

[0023] Figure 2 This is a schematic diagram of the fiber diameter of the PEEK fine denier monofilament obtained in Example 1 of the present invention under an electron microscope.

[0024] Figure 3 This is a schematic diagram of the fiber diameter of the PEEK fine denier monofilament obtained in Example 2 of the present invention under an electron microscope.

[0025] Figure 4 This is a schematic diagram of the fiber diameter of the PEEK fine denier monofilament obtained in Example 3 of the present invention under an electron microscope. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Example 1

[0027] The PEEK fine denier monofilament used in the water electrolysis hydrogen production membrane is produced by spinning PEEK fine denier monofilament for PEM electrolyzer proton exchange membranes. This spinning process includes the following steps:

[0028] S1: PEEK resin is sliced ​​and dried;

[0029] S2: The dried PEEK resin chips are added to a screw extruder for melt extrusion. The temperature range of the feed section of the screw extruder is 380℃, the temperature range of the compression section is 450℃, and the temperature range of the metering section is 440℃. Increasing the temperature of the compression and metering sections further improves the fluidity of the PEEK melt, making the PEEK melt less viscous and making the monofilaments spun from the PEEK melt easier to stretch and refine in subsequent processes.

[0030] S3: The PEEK melt extruded by the screw extruder is first filtered through a filter screen group. After filtration, the PEEK melt passes through a layer of metal sand and then enters the spinneret. It is then ejected from the spinneret holes to form several nascent monofilaments. Throughout the entire process of S3, the temperature of the PEEK melt is maintained at 440℃. This ensures that the temperature of the spinneret is uniform and that the melt is stable when it is ejected from the spinneret holes.

[0031] The filter assembly comprises three layers. In this embodiment, the first layer of the three-layer filter assembly along the flow direction of the PEEK melt consists of stacked 1600-mesh filter sheets, the second layer consists of stacked 1800-mesh filter sheets, and the third layer consists of stacked 2000-mesh filter sheets. Using a 1600-2000 mesh filter assembly to filter the PEEK melt effectively removes impurities from the PEEK melt. This not only increases the stability of the PEEK melt during spinning through the spinneret but also makes the spun PEEK monofilaments less prone to breakage during subsequent stretching, making the PEEK monofilaments easier to stretch and refine in subsequent processes.

[0032] The metal sand layer is composed of 40-mesh metal sand; the thickness of the metal sand layer is 1cm; the metal sand is made of stainless steel. The metal sand layer can keep the PEEK melt pressure and flow rate uniform, further increasing the stability of the PEEK melt when spinning through the spinneret, further improving the performance of the PEEK monofilament after spinning, making the PEEK monofilament less prone to breakage during subsequent stretching, and making the PEEK monofilament easier to stretch and refine in subsequent processes.

[0033] Among them, such as Figure 1 As shown, the spinneret's spinneret orifice consists of an upper spinneret guide hole 1 and a lower spinneret micro-orifice 2. The aspect ratio of the spinneret micro-orifice is 9, that is: Figure 1 In the diagram, X / Y=9, where X is the length of the spinneret orifice and Y is the diameter of the spinneret orifice. This spinneret orifice aspect ratio design effectively reduces the extrusion swelling effect, eliminates unstable melt flow, and increases the stability of PEEK melt during spinning through the spinneret. This makes PEEK monofilaments less prone to breakage during subsequent stretching and easier to refine, providing further assurance for producing fine denier PEEK monofilaments with a fiber diameter of less than 25μm. On the other hand, the spun PEEK monofilaments are relatively fine, allowing for initial refinement before further refinement during subsequent stretching.

[0034] S4: After cooling the nascent monofilaments, oil them and bundle them together to form nascent multifilaments;

[0035] S5: The nascent multifilament is stretched, shaped, wound, and then separated to form PEEK fine denier monofilaments with a fiber diameter of 22.826 μm; the fiber diameter of the PEEK fine denier monofilament is as follows: Figure 2As shown; the stretching of the nascent multifilament is a two-stage stretching process. The first stage stretching is completed by a primary stretching hot roller with a roller temperature of 210℃ and a roller speed of 300m / min, and the nascent multifilament's residence time on the primary stretching hot roller is 0.4 seconds. The second stage stretching is completed by a secondary stretching hot roller with a roller temperature of 240℃ and a roller speed of 1200m / min, and the nascent multifilament's residence time on the secondary stretching hot roller is 0.2 seconds. The stretching ratio between the secondary and primary stretching hot rollers is 4. The setting of the nascent multifilament is completed by a setting hot roller with a roller temperature of [missing information - likely a temperature value]. The temperature is 240℃, the roller speed is 1100m / min, and the residence time of the nascent multifilament on the three-stage setting hot roller is 0.2 seconds. In this stretching and setting process, the parameters of the first-stage stretching hot roller, the second-stage stretching hot roller, and the setting hot roller are specially designed for the performance of PEEK monofilaments obtained after the previous processes. Through the parameter design of the first-stage stretching hot roller, the second-stage stretching hot roller, and the setting hot roller of this invention, PEEK fine denier monofilaments can be stretched to 22.826μm, while ensuring that the performance of the stretched PEEK fine denier monofilaments can meet the requirements for the preparation of water electrolysis hydrogen production membranes. Example 2

[0036] The PEEK fine denier monofilament used in the water electrolysis hydrogen production membrane is produced by spinning PEEK fine denier monofilament for PEM electrolyzer proton exchange membranes. This spinning process includes the following steps:

[0037] S1: PEEK resin is sliced ​​and dried;

[0038] S2: The dried PEEK resin chips are added to a screw extruder for melt extrusion. The feed section temperature range of the screw extruder is 330℃, the compression section temperature range is 390℃, and the metering section temperature range is 390℃. The above temperature design of the compression and metering sections can further improve the fluidity of the PEEK melt, make the PEEK melt less viscous, and make the monofilaments spun from the PEEK melt easier to stretch and refine in subsequent processes.

[0039] S3: The PEEK melt extruded by the screw extruder is first filtered through a filter screen group. After filtration, the PEEK melt passes through a layer of metal sand and then enters the spinneret. It is then ejected from the spinneret holes to form several nascent monofilaments. Throughout the entire process of S3, the temperature of the PEEK melt is maintained at 390℃.

[0040] The filter assembly consists of filter screens with a mesh size of 1600-2000. The filter assembly comprises three layers. In this embodiment, along the flow direction of the PEEK melt, the first layer is composed of stacked 1600-mesh filter screens, the second layer is composed of stacked 1800-mesh filter screens, and the third layer is composed of stacked 2000-mesh filter screens. Using a 1600-2000 mesh filter assembly to filter the PEEK melt effectively removes impurities from the melt, increasing the efficiency of the PEEK melt through the spinneret. The spinneret provides stability during spinning and prevents the PEEK monofilaments from breaking during subsequent stretching, making them easier to refine. The metal grit layer consists of 16-mesh metal grit with a thickness of 1cm. The metal grit is made of stainless steel. The metal grit layer helps maintain uniform melt pressure and flow rate in the PEEK melt, further increasing the stability of the PEEK melt during spinning and improving the performance of the spun PEEK monofilaments. This makes the PEEK monofilaments less prone to breakage during subsequent stretching and easier to refine.

[0041] Among them, such as Figure 1 As shown, the spinneret's spinneret orifice consists of an upper spinneret guide hole 1 and a lower spinneret micro-orifice 2. The aspect ratio of the spinneret micro-orifice is 8, that is: Figure 1 In the diagram, X / Y = 8, where X is the length of the spinneret orifice and Y is the diameter of the spinneret orifice. This spinneret orifice aspect ratio design effectively reduces the extrusion swelling effect, eliminates unstable melt flow, and increases the stability of PEEK melt during spinning through the spinneret. This makes PEEK monofilaments less prone to breakage during subsequent stretching and easier to refine, providing further assurance for producing fine denier PEEK monofilaments with a fiber diameter of less than 25μm. On the other hand, the spun PEEK monofilaments are relatively fine, allowing for initial refinement before further refinement during subsequent stretching.

[0042] S4: After cooling the nascent monofilaments, oil them and bundle them together to form nascent multifilaments;

[0043] S5: The nascent multifilament is stretched, shaped, wound, and then separated to form PEEK fine denier monofilaments with a fiber diameter of 24.499μm; the fiber diameter of the PEEK fine denier monofilament is as follows: Figure 3As shown; the stretching of the nascent multifilament is a two-stage stretching process. The first stretching is completed by a primary stretching hot roller with a roller temperature of 160℃ and a roller speed of 400m / min, and the nascent multifilament's residence time on the primary stretching hot roller is 0.3 seconds. The second stretching is completed by a secondary stretching hot roller with a roller temperature of 180℃ and a roller speed of 800m / min, and the nascent multifilament's residence time on the secondary stretching hot roller is also 0.3 seconds. The stretching ratio between the secondary and primary stretching hot rollers is 2. The setting of the nascent multifilament is completed by a setting hot roller with a roller temperature of 1℃. The temperature is 80℃, the roller speed is 700m / min, and the residence time of the nascent multifilament on the third-stage setting hot roller is 0.3 seconds. In this stretching and setting process, the parameters of the first-stage stretching hot roller, the second-stage stretching hot roller, and the setting hot roller are specially designed for the performance of PEEK monofilaments obtained after the previous processes. Through the parameter design of the first-stage stretching hot roller, the second-stage stretching hot roller, and the setting hot roller of this invention, PEEK fine denier monofilaments can be stretched to a fiber diameter of 24.499μm, while ensuring that the performance of the stretched PEEK fine denier monofilaments can meet the requirements for the preparation of water electrolysis hydrogen production diaphragms. Example 3

[0044] The PEEK fine denier monofilament used in the water electrolysis hydrogen production membrane is produced by spinning PEEK fine denier monofilament for PEM electrolyzer proton exchange membranes. This spinning process includes the following steps:

[0045] S1: PEEK resin is sliced ​​and dried;

[0046] S2: The dried PEEK resin chips are added to a screw extruder for melt extrusion. The temperature range of the feed section of the screw extruder is 350℃, the temperature range of the compression section is 420℃, and the temperature range of the metering section is 410℃. The above temperature design of the compression and metering sections can further improve the fluidity of the PEEK melt, make the PEEK melt less viscous, and make the monofilaments spun from the PEEK melt easier to stretch and refine in subsequent processes.

[0047] S3: The PEEK melt extruded by the screw extruder is first filtered through a filter screen group. After filtration, the PEEK melt passes through a layer of metal sand and then enters the spinneret. It is then ejected from the spinneret holes to form several nascent monofilaments. Throughout the entire process of S3, the temperature of the PEEK melt is maintained at 410℃.

[0048] The filter assembly comprises three layers. Along the flow direction of the PEEK melt, the first layer consists of stacked 1600-mesh filter screens, the second layer of 1800-mesh filter screens, and the third layer of 2000-mesh filter screens. The metal abrasive layer consists of 30-mesh metal abrasive with a thickness of 1 cm. Made of stainless steel, the metal abrasive layer helps maintain uniform melt pressure and flow rate, further increasing the stability of the PEEK melt during spinning and improving the performance of the spun PEEK monofilaments. This makes the PEEK monofilaments less prone to breakage during subsequent stretching and facilitates finer stretching.

[0049] Among them, such as Figure 1 As shown, the spinneret's spinneret orifice consists of an upper spinneret guide hole 1 and a lower spinneret micro-orifice 2. The aspect ratio of the spinneret micro-orifice is 10, that is: Figure 1 In the figure, X / Y=10, where X is the length of the spinneret orifice and Y is the diameter of the spinneret orifice. This spinneret orifice length-to-diameter ratio design effectively reduces the extrusion swelling effect, effectively eliminates unstable melt flow, and increases the stability of PEEK melt when spinning through the spinneret. This makes PEEK monofilaments less prone to breakage during subsequent stretching and makes them easier to refine in subsequent stretching. This provides further assurance for producing fine denier PEEK monofilaments with a fiber diameter of less than 25μm. On the other hand, the spun PEEK monofilaments are relatively fine, so the PEEK monofilaments are initially refined to facilitate further refinement during subsequent stretching.

[0050] S4: After cooling the nascent monofilaments, oil them and bundle them together to form nascent multifilaments;

[0051] S5: The nascent multifilament is stretched, shaped, wound, and then separated to form PEEK fine denier monofilaments with a fiber diameter of 23.764 μm; the fiber diameter of the PEEK fine denier monofilament is as follows: Figure 4As shown; the stretching of the nascent multifilament is a two-stage stretching process. The first stretching is completed by a primary stretching hot roller with a roller temperature of 190℃ and a roller speed of 350m / min, and the nascent multifilament's residence time on the primary stretching hot roller is 0.5 seconds. The second stretching is completed by a secondary stretching hot roller with a roller temperature of 230℃ and a roller speed of 1100m / min, and the nascent multifilament's residence time on the secondary stretching hot roller is 0.4 seconds. The stretching ratio between the secondary and primary stretching hot rollers is 3.14. The setting of the nascent multifilament is completed by a setting hot roller with a roller temperature of [missing information - likely a temperature value]. The temperature is 230℃ and the roller speed is 1000m / min; the residence time of the nascent multifilament on the third-stage setting hot roller is 0.4 seconds; in this stretching and setting process, the parameters of the first-stage stretching hot roller, the second-stage stretching hot roller and the setting hot roller are specially designed for the performance of PEEK monofilaments obtained after the previous processes. Through the parameter design of the first-stage stretching hot roller, the second-stage stretching hot roller and the setting hot roller of this invention, PEEK fine denier monofilaments can be stretched to a fiber diameter of 23.764μm, and the performance of the stretched PEEK fine denier monofilaments can meet the requirements for the preparation of water electrolysis hydrogen production diaphragms.

[0052] To provide a more intuitive understanding of the data changes in each embodiment of the present invention, the data of each embodiment are explained below using tables. Table 1 lists the following: feed section temperature, compression section temperature, metering section temperature of the screw conveyor, mesh count of each layer of the filter screen group, thickness and mesh count of the metal abrasive, and the ratio of the spinneret's micro-orifice length to the spinneret's length. Table 1:

[0053]

[0054] The roller temperature, roller speed, and residence time of the first-stage stretching hot roller, the roller temperature, roller speed, and residence time of the second-stage stretching hot roller, the stretching ratio, the roller temperature, roller speed, and residence time of the setting hot roller, and the PEEK fiber diameter are listed in Table 2: Table 2:

[0055]

[0056] The advantages of this invention are: the entire spinning process is designed, (1) in the PEEK melt extrusion process, the temperature of the screw extruder feed end, compression section and metering section is designed, the temperature of the compression section and metering section is increased, the fluidity of the PEEK melt is further improved, the viscosity of the PEEK melt is reduced, and the monofilament spun from the PEEK melt is easier to stretch and refine in the subsequent process, which provides further assurance for producing fine denier PEEK monofilaments with a fiber diameter of less than 25μm; (2) in the spinneret spinning process, a 1600-2000 mesh filter screen is first used to filter the PEEK melt, effectively filtering out impurities in the PEEK melt, which not only increases the stability of the PEEK melt when spun by the spinneret, but also makes the PEEK melt more stable. The PEEK monofilaments after spinning are not easily broken during subsequent stretching, making them easier to stretch and refine, which provides further assurance for producing fine denier PEEK monofilaments with a fiber diameter of less than 25μm; (3) In the spinneret spinning process, the filtered PEEK melt needs to pass through a layer of metal sand before entering the spinneret. The metal sand layer can keep the PEEK melt pressure and flow rate uniform, further increasing the stability of the PEEK melt during spinneret spinning, further improving the performance of the spun PEEK monofilaments, making them less prone to breakage during subsequent stretching, and making them easier to stretch and refine, which provides further assurance for producing fine denier PEEK monofilaments with a fiber diameter of less than 25μm; (4) In the spinneret spinning process, the aspect ratio of the spinneret micro-orifices is designed to be 8-10. This aspect ratio design effectively reduces the extrusion swelling effect, eliminates unstable melt flow, and increases the stability of the PEEK melt during spinneret spinning. This makes the PEEK monofilaments less prone to breakage during subsequent stretching, and facilitates finer stretching in subsequent processes, further ensuring the production of fine denier PEEK monofilaments with a fiber diameter of less than 25μm. Furthermore, the resulting finer PEEK monofilaments allow for preliminary refinement during subsequent stretching, further ensuring the production of fine denier PEEK monofilaments with a fiber diameter of less than 25μm. (5) In the stretching and shaping process, the roller temperature, roller speed, residence time and stretching ratio of each stretching hot roller and shaping roller were designed to ensure that the PEEK fine denier monofilament is stretched to a fiber diameter of less than 25μm, and that the performance of the stretched PEEK fine denier monofilament can meet the requirements for the preparation of water electrolysis hydrogen production membrane; (6) PEEK fine denier monofilament with a fiber diameter of less than 25μm can be obtained. The substrate made by the PEEK fine denier monofilament of this invention is thinner than the traditional substrate, so that the proton exchange membrane made is also thinner. The reduction in the thickness of the proton exchange membrane will improve the proton conductivity, reduce the internal resistance of the electrolytic cell, increase the current density, reduce the decomposition voltage, thereby improving the electrolysis efficiency of PEM water electrolysis hydrogen production.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any modifications or equivalent changes made based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. A PEEK fine denier monofilament spinning process for proton exchange membranes in PEM electrolyzers, characterized in that: Includes the following steps: S1: PEEK resin is sliced ​​and dried; S2: The dried PEEK resin chips are added to a screw extruder for melt extrusion. The temperature range of the feed section of the screw extruder is 330-380℃, the temperature range of the compression section is 390-450℃, and the temperature range of the metering section is 390-440℃. S3: The PEEK melt extruded from the screw extruder is first filtered through a filter screen assembly. The filtered PEEK melt then passes through a layer of metal grit before entering the spinneret. It is then ejected from the spinneret orifices to form several nascent monofilaments. Throughout step S3, the temperature of the PEEK melt is maintained at 390–440°C. The filter screen assembly consists of three layers. Along the flow direction of the PEEK melt, the first layer is composed of stacked 1600-mesh filter screens, the second layer is composed of stacked 1800-mesh filter screens, and the third layer is composed of stacked 2000-mesh filter screens. The metal grit layer consists of metal grit with a mesh size of 16–40. The spinneret orifices consist of an upper section of spinneret guide holes and a lower section of spinneret micro-holes. The aspect ratio of the spinneret micro-holes is 9. S4: After cooling the nascent monofilaments, oil them and bundle them together to form nascent multifilaments; S5: The nascent multifilament is stretched, shaped, and wound before being separated into fine denier PEEK monofilaments with a fiber diameter of less than 25μm. The stretching of the nascent multifilament is a two-stage stretching process. The first stage stretching is completed by a primary stretching hot roller with a roller temperature of 160–210℃ and a roller speed of 300–400m / min. The second stage stretching is completed by a secondary stretching hot roller with a roller temperature of 180–240℃ and a roller speed of 800–1200m / min. The stretching ratio between the secondary and primary stretching hot rollers is 2–4. The shaped multifilament is shaped by a shaped hot roller with a roller temperature of 180–240℃ and a roller speed of 700–1100m / min.

2. The PEEK fine denier monofilament spinning process for PEM electrolytic cell proton exchange membranes according to claim 1, characterized in that: The thickness of the metal sand layer is 1 cm.

3. The PEEK fine denier monofilament spinning process for PEM electrolytic cell proton exchange membranes according to claim 1, characterized in that: In S5, the stretching of the nascent multifilament is a two-stage stretching process. The first stretching is completed by a primary stretching hot roller with a roller temperature of 210℃ and a roller speed of 300m / min. The second stretching is completed by a secondary stretching hot roller with a roller temperature of 240℃ and a roller speed of 1200m / min. The stretching ratio between the secondary and primary stretching hot rollers is 4. The setting of the nascent multifilament is completed by a setting hot roller with a roller temperature of 240℃ and a roller speed of 1100m / min.

4. PEEK fine denier monofilaments for proton exchange membranes in PEM electrolyzers, characterized in that: The PEEK fine denier monofilament is obtained by the PEEK fine denier monofilament spinning process of the PEM electrolytic cell proton exchange membrane as described in any one of claims 1 to 3.

Images