Preparation process of alkaline electrolytic cell pole frame plastic layer, obtained pole frame and application of pole frame

Abstract

The invention relates to a preparation technology of an alkaline electrolytic cell pole frame plastic layer, an obtained pole frame and application of the pole frame, and belongs to the technical field of alkaline electrolytic cell pole frame materials. The technology comprises the steps that S1, after a metal electrode frame is cleaned, surface roughening treatment is conducted; s2, coating the surface of the metal pole frame with a silane coupling agent, and curing to form an activation layer; s3, mixing, melting and blending the plastic layer composite material to obtain a coating material; s4, the metal pole frame is put into a mold, the cladding material is injected into a mold cavity after being molten, and a continuous cladding layer is formed on the outer surface of the metal pole frame; and S5, cooling to complete preparation. According to the technical scheme, a technical thought of preparing a pole frame product by coating a metal pole frame with plastic is provided, a set of processing technology with high long-term operation reliability of a plastic layer is given, and the problem that in the prior art, the strength and the strong alkali corrosion resistance at high temperature of a pure metal pole frame and a pure plastic pole frame are difficult to balance is solved; the composite pole frame product has good market competitiveness.

Description

Technical Field

[0001] This application relates to a preparation process of the plastic layer of an alkaline electrolytic cell electrode frame, the resulting electrode frame, and its application, belonging to the technical field of alkaline electrolytic cell electrode frame materials. Background Technology

[0002] Alkaline electrolyzers are typically formed by stacking multiple electrolysis units. The electrode frame, as an important structural component in the electrolysis unit, is used to support the electrode assembly and diaphragm, and to achieve positioning and sealing between adjacent electrolysis units. Its performance directly affects the operational stability and service life of the electrolyzer.

[0003] In existing technologies, metal electrode frames are widely used due to their high mechanical strength, good dimensional stability, and ease of current conduction. To improve the corrosion resistance of metal electrode frames in alkaline electrolyte environments, their surfaces are typically treated with protective processes such as nickel plating. However, under the combined effects of long-term high temperature, high concentration of alkaline solution, and electrochemical action, the nickel plating layer may still dissolve, peel off, or fail locally, leading to exposure of the base metal and affecting the service life of the electrode frame and the operational reliability of the electrolytic cell.

[0004] Meanwhile, with the development of polymer materials technology, plastic electrode frames have gradually been applied in some alkaline electrolyzers. Plastic electrode frames generally possess good corrosion resistance and molding flexibility, and can mitigate metal corrosion problems to some extent. However, limited by the material's mechanical strength, heat resistance, and long-term dimensional stability, plastic electrode frames still have certain limitations in high-pressure, high-temperature, or large-size electrolyzer applications. In particular, the strength of pure plastic electrode frames is far inferior to that of pure metal electrode frames, while large-scale alkaline water electrolysis hydrogen production equipment with multiple stacked electrolysis units represents the current market demand. Therefore, a plastic-coated structure combining metal and plastic is proposed. This involves using metal as the main structure of the electrode frame and applying a plastic coating layer to its outer surface. The aim is to improve the corrosion resistance and service life of the electrode frame in alkaline electrolysis environments while retaining the mechanical properties and structural stability of the metal electrode frame.

[0005] However, current technologies for plastic-coated metal electrode frames still have room for improvement in terms of the selection of coating plastic materials, processing technology, and long-term operational reliability of the plastic layer. Therefore, it is necessary to address the problem that existing pure metal and pure plastic electrode frames cannot balance the strength of the frame and its resistance to high temperature and strong alkali corrosion. This paper proposes a technical approach for plastic-coated metal electrode frames, a processing technology with high long-term operational reliability of the plastic layer, and optimization of the plastic layer material to adapt to the processing technology of plastic-coated metal electrode frames. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a process for preparing a plastic coating on an alkaline electrolyzer electrode frame, along with the resulting electrode frame and its applications. The proposed solution outlines a technical approach for preparing electrode frame products by coating a metal electrode frame with plastic, and provides a complete processing technology for the plastic coating, ensuring high long-term operational reliability. This addresses the challenge of balancing the strength and high-temperature resistance to strong alkali corrosion of pure metal and pure plastic electrode frames in existing technologies. The resulting composite electrode frame product combines the strength of a near-metal electrode frame with the high-temperature resistance to strong alkali corrosion of plastic, resulting in a predictably longer service life. It is highly suitable for large-scale water electrolysis hydrogen production equipment with multiple stacked electrolysis units, and this electrode frame product possesses strong market competitiveness.

[0007] This application provides a process for preparing the plastic layer of the electrode frame in an alkaline electrolytic cell, the process comprising the following steps: S1. After cleaning the metal frame, perform surface roughening treatment; S2. After coating the surface of the metal pole frame with a silane coupling agent, it is cured to form an activation layer; S3. Mix and melt-blend the plastic composite material to obtain the coating material; S4. Place the metal pole frame into the mold, and inject the molten coating material into the mold cavity to form a continuous coating layer on the outer surface of the metal pole frame. S5. After cooling, demold to complete the preparation of the alkaline electrolytic cell electrode frame plastic layer.

[0008] Optionally, the silane coupling agent in step S2 is a fluorosilane coupling agent, and the curing process includes: heating the metal electrode frame treated with the fluorosilane coupling agent to 100-120°C for 60-120 minutes under a relative humidity of 30-50%, and then letting it stand at room temperature for at least 30 minutes after curing.

[0009] By curing the metal electrode frame treated with fluorosilane coupling agent at 100-120℃ under conditions of 30-50% relative humidity, a dense and structurally stable interface activation layer can be formed on the metal surface. This interface activation layer not only significantly improves the initial interfacial shear strength between the metal and the polysulfone plastic layer, but also maintains good interfacial integrity after alkaline media and thermal cycling, thereby improving the peel strength retention rate and interfacial strength retention rate. If the curing temperature is too low, the interfacial layer reaction may be insufficient; if it is too high, it may cause excessive cross-linking and embrittlement of the interfacial layer, both of which are detrimental to the long-term stability of the interfacial bonding performance.

[0010] Optionally, step S4 includes: preheating the metal electrode frame to 100~150°C and then placing it into the mold; melting the coating material and injecting it into the mold cavity to form a continuous coating layer on the outer surface of the metal electrode frame.

[0011] Preheating the metal electrode frame to 100-150℃ before coating molding effectively reduces the temperature difference between the metal substrate and the molten coating material. This prevents the coating material from instantaneously cooling upon contact with the metal surface, which would affect its flow and wetting properties. It also facilitates the uniform spreading of the coating material on the metal surface, forming a continuous and dense coating layer. Simultaneously, an appropriate preheating temperature promotes interfacial diffusion and bonding between the coating material and the activated metal surface layer, improving interfacial bonding strength. If the preheating temperature is too low, insufficient flow and incomplete interface filling of the coating material on the metal surface may occur, leading to poor local bonding. Conversely, if the preheating temperature is too high, it may increase the thermal stress of the interfacial layer or cause instability in the activated surface layer structure, which is detrimental to the long-term maintenance of interfacial bonding performance.

[0012] Optionally, the demolding process after cooling in step S5 includes a three-stage annealing process: the first stage annealing process, holding at 170~190℃ for 2~10 minutes; the second stage annealing process, holding at 130~150℃ for 30~60 minutes; and the third stage annealing process, holding at 70~90℃ for 10~20 minutes. After demolding, the material is allowed to cool naturally to room temperature.

[0013] Optionally, the surface roughening treatment in step S1 includes: using sandblasting, with the sandblasting medium being 80~200 mesh quartz sand, the sandblasting pressure being 0.3~0.7MPa, the sandblasting time being 10~30s, and the surface roughness after roughening treatment being 1.5~4.0μm.

[0014] Optionally, the coating material, by weight, comprises the following components: 100 parts polysulfone; 20-30 parts PFA resin; 5-15 parts bisphenol A type polycarbonate; 2-6 parts graphene oxide; 5-10 parts fluorosilane coupling agent; 5-20 parts chopped quartz fibers; 2-8 parts hollow glass microspheres; and 2-6 parts spherical silica powder.

[0015] Optionally, the melt index of the PFA resin is 14~18 g / 10 min; Optionally, the melt index of the bisphenol A type polycarbonate is 3.9~6 g / 10 min; the use of bisphenol A type polycarbonate with a smaller melt index in this application is more beneficial to improving the alkali resistance of the electrode frame material, and can also take advantage of the excellent properties of bisphenol A type polycarbonate itself.

[0016] In this application, the amount of bisphenol A polycarbonate added is relatively less than that of polysulfone and PFA resin, thus allowing polysulfone and PFA resin to balance the slightly poor alkali resistance of bisphenol A polycarbonate. At the same time, it was found that the addition of quartz short-cut fibers can further improve the slightly poor alkali resistance of bisphenol A polycarbonate. Therefore, the addition of quartz short-cut fibers in this application can also increase the amount of bisphenol A polycarbonate added without causing a significant decrease in the overall strong alkali resistance of the pole frame material.

[0017] Optionally, the melt index of the polysulfone is 8~12 g / 10 min; Optionally, the length of the quartz chopped fibers is 10~20mm; Optionally, the particle size range of the hollow glass microspheres is 50~80μm; Optionally, the particle size range of the spherical silica powder is 1.5~2.0 μm; By rationally combining linear chopped quartz fibers, mesoscale spherical hollow glass microspheres, and microscale spherical silica powder, the chopped quartz fibers primarily serve as the skeleton reinforcement and main load-bearing component. They can form an effective spatial skeleton structure within the coating material, significantly improving flexural and tensile strength. Their linear morphology provides attachment and filling space for mesoscale and microscale fillers, which is beneficial for constructing a multi-scale continuous reinforcement system. The hollow glass microspheres play a mesoscale filling and stress regulation role, effectively filling the large gaps formed between the chopped quartz fibers and between the fibers and the resin matrix. The spherical structure ensures uniform stress distribution around the microspheres, reducing local stress concentration. The hollow structure ensures both rigidity and lightweight design. It helps reduce the overall density of the coating material; spherical silica powder mainly plays the role of micro-scale dense filling, which can further fill the small pores between hollow glass microspheres and resin matrix, improve the overall density of composite materials, reduce the penetration channels of high-temperature alkaline solutions, and improve the dimensional stability and creep resistance of the coating material under high-temperature conditions; fillers of different sizes fill the structural gaps in order from large to small, significantly reducing the internal porosity of the material, which can build a continuous and dense load-bearing and force transmission network, making the load more evenly distributed under high-temperature conditions, effectively inhibiting thermal stress concentration, material creep and microcrack initiation, so that the mechanical strength, dimensional stability and long-term service reliability of the coating material in high-temperature and strong alkaline environment are significantly improved.

[0018] Optionally, the graphene oxide has a particle size of 10-20 μm and an oxygen content of 45-62 at%; Graphene oxide possesses a two-dimensional sheet structure, a high specific surface area, and abundant oxygen-containing functional groups. When combined with fluorosilane coupling agents, the aggregation of graphene oxide can be significantly improved, which helps it to disperse more uniformly in the plastic matrix. The hydroxyl and carboxyl functional groups on the surface can interact with the fluorosilane coupling agents to enhance the interfacial bonding stability between the inorganic filler and the resin matrix, forming a microscale reinforcing network in the polymer matrix. Its sheet structure helps to suppress the slippage and creep of polymer molecular chains under high temperature conditions, thereby improving the elastic modulus and deformation resistance of the coated material.

[0019] This application provides an alkaline electrolytic cell electrode frame obtained by the above-described preparation process.

[0020] This application provides the application of the above-mentioned alkaline electrolyzer electrode frame in alkaline electrolyzer products.

[0021] The beneficial effects of this application include, but are not limited to: 1. According to the preparation process of the alkaline electrolytic cell electrode frame plastic layer of this application, the obtained electrode frame and its application, the fluorosilane coupling agent needs to undergo hydrolysis, condensation, orientation, cross-linking and curing processes to form an effective interfacial bonding layer on the metal surface. The heating curing temperature and relative humidity directly affect the degree of completion of the hydrolysis and condensation reaction of silane molecules and the density and continuity of the coupling agent on the metal surface, thus affecting the thermal stability and chemical stability of the interfacial layer. Under the curing conditions of this application, the silanol groups in the fluorosilane coupling agent can fully undergo condensation reaction to form a continuous and dense silicon-oxygen network structure on the metal surface. A stable chemical and physical synergistic bond can be formed between the interfacial activation layer and the subsequent coating layer material, which significantly improves the shear strength retention rate and peel strength retention rate of the plastic layer and the metal.

[0022] 2. Based on the preparation process of the alkaline electrolytic cell electrode frame plastic layer of this application, the resulting electrode frame, and its application, an optimal annealing process was explored. The first stage involves holding the coating at 170~190℃ for a short time, which is beneficial for the coating material to complete the initial structural adjustment under conditions higher than the glass transition temperature, so that the coating layer can fully adhere to the metal surface and avoid inconsistent instantaneous shrinkage of the interface due to rapid cooling. The second stage involves annealing at 130~150℃ for a longer time, which helps to further release the residual thermal stress inside the coating layer and at the interface, reduce the interface stress concentration caused by the difference in thermal expansion coefficients between the metal and the plastic layer, and thus improve the stability of the interface bonding. Finally, the third stage involves low-temperature stabilization treatment at 70~90℃, which allows the coating structure to gradually transition to a state close to the service temperature, providing stable structural conditions for demolding. Through the above three-stage annealing and cooling, stress relief and structural stability of the coating layer can be achieved without introducing drastic temperature differences, avoiding problems such as interface cracking, delamination, or warping during demolding or subsequent use, thereby improving the long-term reliability of the interface bonding performance between the metal electrode frame and the plastic layer.

[0023] 3. According to the preparation process of the alkaline electrolytic cell electrode frame plastic layer of this application, the resulting electrode frame and its application, the coating material is mainly polysulfone material, combined with PFA resin and bisphenol A type polycarbonate. Among them, polysulfone, as the continuous phase and structural skeleton phase, provides the coating material with excellent heat deformation resistance, good strong alkali corrosion stability and stable mechanical properties. The introduction of PFA resin forms a dispersed corrosion-resistant phase in the polysulfone matrix, which plays a physical barrier role against alkaline media. Under high temperature conditions, PFA can still maintain a stable molecular structure, which helps to inhibit the performance decay of polysulfone in long-term hot alkaline environment, thereby significantly improving the mechanical property retention rate of the coating material under high temperature and strong alkaline conditions. The introduction of bisphenol A type polycarbonate can form a toughening modified phase in the polysulfone continuous phase, improve the bending strength and impact resistance of the coating material under high temperature conditions, reduce the cracking risk caused by thermal stress concentration, and under high temperature conditions, the presence of bisphenol A type polycarbonate helps to delay the rapid decrease of material modulus, improve the load-bearing capacity of the overall structure, and improve the brittle defects of the polysulfone system. Detailed Implementation

[0024] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments. Unless otherwise specified, the raw materials and reagents in the embodiments of the present application are all purchased through commercial channels.

[0025] The present application scheme will be described below through specific implementation methods.

[0026] Example 1 This application provides a process for preparing the plastic layer of the electrode frame in an alkaline electrolytic cell, comprising the following steps: 1) Pretreatment and surface roughening of metal pole frames The carbon steel metal pole frame is degreased and cleaned to remove processing residues, oil, and oxides. It is then immersed in an alkaline cleaning solution and ultrasonically cleaned. After cleaning, it is rinsed with deionized water and dried. The surface is roughened by sandblasting. The sandblasting medium is 80~200 mesh quartz sand, the sandblasting pressure is 0.5MPa, and the sandblasting time is 20s. After treatment, a uniform micro-rough structure is formed on the metal surface, and the roughness Ra is controlled within the range of 1.5~4.0μm.

[0027] 2) Surface activation of silane coupling agents After uniformly brushing a fluorosilane coupling agent onto the roughened metal electrode frame surface, it was cured at a curing temperature of 110℃, an ambient relative humidity of 41% RH, and a holding time of 90 min. After curing, the metal electrode frame was left to stand at room temperature for 30 min.

[0028] 3) Prepare the wrapping materials The coating material comprises the following components by weight: 100 parts polysulfone; 20 parts PFA resin; 30 parts bisphenol A polycarbonate; 4 parts graphene oxide; 7.5 parts fluorosilane coupling agent; 12.5 parts chopped quartz fibers; 5 parts hollow glass microspheres; and 4 parts spherical silica powder. The melt index of the PFA resin is 16.3 g / 10 min; the melt index of the bisphenol A polycarbonate is 5.5 g / 10 min; and the melt index of the polysulfone is 10.3 g / 10 min. The length of the chopped quartz fibers is 10–20 mm, the particle size range of the hollow glass microspheres is 50–80 μm, the particle size range of the spherical silica powder is 1.5–2.0 μm, the particle size of the graphene oxide is 10–20 μm, and the oxygen content is 53.7 at.

[0029] The raw materials are mixed and melt-blended at 310°C to obtain the coating material for later use.

[0030] 4) Metal cladding with coating materials After preheating the metal electrode frame to 130°C, it is placed in a mold. The coating material is melted at 310°C and injected into the mold cavity. Under pressure, the coating material forms a continuous coating layer on the outer surface of the metal electrode frame. Then, it is cooled. The cooling process includes three-stage annealing: the first stage annealing is held at 180°C for 6 minutes, the second stage annealing is held at 140°C for 45 minutes, and the third stage annealing is held at 80°C for 15 minutes. Then, it is demolded at the third stage annealing temperature and placed in air to cool naturally to room temperature, thus obtaining the alkaline electrolytic cell electrode frame product containing the alkaline electrolytic cell electrode frame plastic layer.

[0031] Further processing, such as grinding and boring, can be performed on the plastic layer of the alkaline electrolytic cell electrode frame as needed.

[0032] Example 2 This application provides a process for preparing the plastic layer of the electrode frame in an alkaline electrolytic cell, comprising the following steps: 1) Pretreatment and surface roughening of metal pole frames The carbon steel metal pole frame is degreased and cleaned to remove processing residues, oil, and oxides. It is then immersed in an alkaline cleaning solution and ultrasonically cleaned. After cleaning, it is rinsed with deionized water and dried. The surface is roughened by sandblasting. The sandblasting medium is 80~200 mesh quartz sand, the sandblasting pressure is 0.3MPa, and the sandblasting time is 30s. After treatment, a uniform micro-rough structure is formed on the metal surface, and the roughness Ra is controlled within the range of 1.5~4.0μm.

[0033] 2) Surface activation of silane coupling agents After uniformly brushing a fluorosilane coupling agent onto the roughened metal electrode frame surface, it is cured at a curing temperature of 100℃, an ambient relative humidity of 50% RH, and a holding time of 120 min. After curing, the metal electrode frame is left to stand at room temperature for 30 min.

[0034] 3) Prepare the wrapping materials The coating material comprises the following components by weight: 100 parts polysulfone; 10 parts PFA resin; 20 parts bisphenol A polycarbonate; 2 parts graphene oxide; 5 parts fluorosilane coupling agent; 5 parts chopped quartz fibers; 2 parts hollow glass microspheres; and 2 parts spherical silica powder. The melt index of the PFA resin is 14.3 g / 10 min; the melt index of the bisphenol A polycarbonate is 3.9 g / 10 min; and the melt index of the polysulfone is 8.6 g / 10 min. The length of the chopped quartz fibers is 10–20 mm, the particle size range of the hollow glass microspheres is 50–80 μm, the particle size range of the spherical silica powder is 1.5–2.0 μm, the particle size of the graphene oxide is 10–20 μm, and the oxygen content is 45.0 at.

[0035] The raw materials are mixed and melt-blended at 320°C to obtain the coating material for later use.

[0036] 4) Metal cladding with coating materials After preheating the metal electrode frame to 100°C, it is placed in a mold. The coating material is melted at 320°C and injected into the mold cavity. Under pressure, the coating material forms a continuous coating layer on the outer surface of the metal electrode frame. Then, it is cooled. The cooling process includes three-stage annealing: the first stage annealing is held at 170°C for 10 minutes, the second stage annealing is held at 130°C for 60 minutes, and the third stage annealing is held at 70°C for 20 minutes. Then, it is demolded at the third stage annealing temperature and placed in air to cool naturally to room temperature, thus obtaining the alkaline electrolytic cell electrode frame product containing the alkaline electrolytic cell electrode frame plastic layer.

[0037] Further processing, such as grinding and boring, can be performed on the plastic layer of the alkaline electrolytic cell electrode frame as needed.

[0038] Example 3 This application provides a process for preparing the plastic layer of the electrode frame in an alkaline electrolytic cell, comprising the following steps: 1) Pretreatment and surface roughening of metal pole frames The carbon steel metal pole frame is degreased and cleaned to remove processing residues, oil, and oxides. It is then immersed in an alkaline cleaning solution and ultrasonically cleaned. After cleaning, it is rinsed with deionized water and dried. The surface is roughened by sandblasting. The sandblasting medium is 80~200 mesh quartz sand, the sandblasting pressure is 0.7MPa, and the sandblasting time is 10s. After treatment, a uniform micro-rough structure is formed on the metal surface, and the roughness Ra is controlled within the range of 1.5~4.0μm.

[0039] 2) Surface activation of silane coupling agents After uniformly brushing a fluorosilane coupling agent onto the roughened metal electrode frame surface, it is cured at a curing temperature of 120℃, an ambient relative humidity of 30% RH, and a holding time of 60 min. After curing, the metal electrode frame is left to stand at room temperature for 30 min.

[0040] 3) Prepare the wrapping materials The coating material comprises the following components by weight: 100 parts polysulfone; 30 parts PFA resin; 40 parts bisphenol A type polycarbonate; 6 parts graphene oxide; 10 parts fluorosilane coupling agent; 20 parts chopped quartz fibers; 8 parts hollow glass microspheres; and 6 parts spherical silica powder. The melt index of the PFA resin is 18.0 g / 10 min; the melt index of the bisphenol A type polycarbonate is 5.9 g / 10 min; and the melt index of the polysulfone is 11.4 g / 10 min. The length of the chopped quartz fibers is 10–20 mm, the particle size range of the hollow glass microspheres is 50–80 μm, the particle size range of the spherical silica powder is 1.5–2.0 μm, the particle size of the graphene oxide is 10–20 μm, and the oxygen content is 62.0 at.

[0041] The raw materials are mixed and melt-blended at 300°C to obtain the coating material for later use.

[0042] 4) Metal cladding with coating materials After preheating the metal electrode frame to 150°C, it is placed in a mold. The coating material is melted at 300°C and injected into the mold cavity. Under pressure, the coating material forms a continuous coating layer on the outer surface of the metal electrode frame. Then, it is cooled. The cooling process includes three-stage annealing: the first stage annealing is held at 190°C for 2 minutes, the second stage annealing is held at 150°C for 30 minutes, and the third stage annealing is held at 90°C for 10 minutes. Then, it is demolded at the third stage annealing temperature and placed in air to cool naturally to room temperature, thus obtaining the alkaline electrolytic cell electrode frame product containing the alkaline electrolytic cell electrode frame plastic layer.

[0043] Further processing, such as grinding and boring, can be performed on the plastic layer of the alkaline electrolytic cell electrode frame as needed.

[0044] Example 4 This embodiment is basically the same as Embodiment 1, except that the relative humidity of the environment during the preparation of the silane coupling agent spark layer is 25%, and the curing time is 130℃ for 90 minutes.

[0045] Example 5 This embodiment is basically the same as Embodiment 1, except that the relative humidity of the environment during the preparation of the silane coupling agent spark layer is 60%, and the curing temperature is 90°C for 90 minutes.

[0046] Example 6 This embodiment is basically the same as embodiment 1, except that in step 4), the metal pole frame is preheated to 90°C and then placed into the mold.

[0047] Example 7 This embodiment is basically the same as embodiment 1, except that in step 4), the metal pole frame is preheated to 170°C and then placed into the mold.

[0048] Example 8 This embodiment is basically the same as embodiment 1, except that the annealing step in step 4) is as follows: first stage annealing treatment, 180°C for 6 minutes, second stage annealing treatment, 140°C for 45 minutes, and then after demolding at the second stage annealing temperature, it is naturally cooled to room temperature.

[0049] Example 9 This embodiment is basically the same as embodiment 1, except that the annealing step in step 4) is as follows: first stage annealing treatment, 180°C for 6 minutes, second stage annealing treatment, 80°C for 15 minutes, and then after demolding at the second stage annealing temperature, it is naturally cooled to room temperature.

[0050] Example 10 This embodiment is basically the same as embodiment 1, except that the annealing step in step 4) is as follows: first stage annealing treatment, 140℃ for 45 minutes, second stage annealing treatment, 80℃ for 15 minutes, and then after demolding at the second stage annealing temperature, it is naturally cooled to room temperature.

[0051] Comparative Example 1 This comparative example is basically the same as Example 1, except that the step of coating with silane coupling agent and then curing to form an activation layer is not performed.

[0052] Test Example 1 The performance of the alkaline electrolytic cell electrode frame plastic layer obtained in the examples and comparative examples was tested, and the results are shown in Table 1 below.

[0053] Interfacial shear strength: The peel strength between the plastic layer and the metal interface is tested according to GB / T 7124-2008 and characterized by interfacial shear strength (MPa). The greater the interfacial shear strength, the stronger the interfacial bonding and the less likely it is to peel off.

[0054] High-temperature resistance to strong alkali corrosion: Prepare a 30wt% potassium hydroxide aqueous solution, completely immerse the sample in the strong alkali solution, seal the container and place it in a constant temperature oven at 80℃ for 240h. After treatment, take it out and clean it, then place the cleaned sample in a vacuum drying oven at 35℃ to dry it. Record whether there are any problems such as bubbles or delamination that indicate interface failure. If there are no problems, continue to conduct subsequent performance tests on the accelerated aging material, detect the interfacial shear strength (MPa) before and after treatment and calculate the shear strength retention rate (%) to evaluate the high-temperature resistance to strong alkali corrosion of the plastic layer.

[0055] Thermal cycling stability: The interface integrity assessment after thermal cycling is conducted in accordance with GB / T 2423.22-2012. The test sample is cycled 10,000 times at a high temperature of 120℃ and a low temperature of 20℃, with a heating and cooling rate of 5℃ / min. The dimensional changes of the plastic layer before and after heat treatment are observed. If no interface cracking occurs, it indicates that the interface constraint between the plastic layer and the metal is good and the dimensional stability is good. The peel strength retention rate (%) is then calculated by testing the peel strength before and after treatment. The peel strength (N / mm) test method is based on GB / T 2790-1995.

[0056] Table 1. Performance test results of the alkaline electrolytic cell electrode frame plastic layer obtained in the examples and comparative examples.

[0057] As shown in Table 1, the alkaline electrolytic cell electrode frame plastic layer and metal electrode frame prepared in this application embodiment exhibit good interfacial bonding performance. In the interfacial bonding strength test, sample failure mainly occurred within the plastic layer, not at the interface between the metal and the plastic layer, indicating good bonding stability at the metal-plastic layer interface. After long-term immersion testing in a strongly alkaline environment, no obvious delamination, blistering, or interfacial damage was observed between the plastic layer and the metal substrate, maintaining good interfacial bonding performance. Under multiple thermal cycling conditions, no obvious interfacial cracks or delamination appeared in the plastic layer, indicating that this interface structure can effectively alleviate the thermal expansion mismatch between the metal and the plastic layer and cope with the thermal stress generated by temperature changes during electrolytic cell operation. Furthermore, after heat treatment and dimensional stability testing, the electrode frame as a whole did not experience significant warping or abnormal dimensional changes, and the plastic layer maintained good deformation coordination under the constraint of the metal substrate, further demonstrating that the formed metal-plastic layer interface structure has good dimensional stability and long-term reliability.

[0058] The plastic layer structure provided in this application achieves a stable and reliable interfacial bond between the plastic layer and the metal substrate by optimizing the metal surface treatment, interface activation and coating molding process. It can maintain good structural integrity and performance under harsh conditions such as alkalinity, high temperature and thermal cycling, and is suitable for long-term stable operation of alkaline electrolytic cells.

[0059] Experimental Example 1 The coating material used in this application is the same material used to prepare the plastic electrode frame of the alkaline electrolytic cell. Since researchers have conducted a lot of research on the plastic electrode frame material of the alkaline electrolytic cell, based on the results of previous research, it has been found that the plastic electrode frame material of the alkaline electrolytic cell can also be used to prepare the plastic layer of the electrode frame of the alkaline electrolytic cell, and exhibits the same excellent performance when used as a coating material.

[0060] The following describes the research content of the plastic electrode frame for alkaline electrolyzers in previous studies.

[0061] Plastic frame material 1 A plastic electrode frame for an alkaline electrolyzer is provided, comprising the following components by weight: 100 parts polysulfone; 25 parts PFA resin; 10 parts bisphenol A polycarbonate; 4 parts graphene oxide; 7.5 parts fluorosilane coupling agent; 12.5 parts chopped quartz fibers; 5 parts hollow glass microspheres; and 4 parts spherical silica powder. The PFA resin has a melt index of 16.3 g / 10 min; the bisphenol A polycarbonate has a melt index of 5.5 g / 10 min; and the polysulfone has a melt index of 10.3 g / 10 min. The chopped quartz fibers have a length of 10-20 mm, the hollow glass microspheres have a particle size range of 50-80 μm, the spherical silica powder has a particle size range of 1.5-2.0 μm, the graphene oxide has a particle size of 10-20 μm, and the oxygen content is 53.7 at%. The preparation method of this plastic electrode frame for the alkaline electrolyzer includes the following steps: 1) Weigh each raw material component according to the weight proportions and dry each raw material component; 2) The dried raw materials are added to a twin-screw extruder for melt blending. The melt-extruded material is granulated to obtain extruded granules, which are then dried. The extruder feed section temperature is 310℃, the intermediate section temperature is 340℃, the discharge section temperature is 355℃, the screw speed is 220rpm, and the melt blending time is 4 minutes. 3) Add the dried extruded granules into the injection molding machine and use the injection molding process to prepare the pole frame preform; the temperature of the front section of the barrel is 320℃, the temperature of the middle section is 340℃, the temperature of the rear section is 360℃, the mold temperature is 165℃, and the injection pressure is 110MPa. 4) After demolding, the electrode frame blank is annealed at 160℃~180℃ for 6 hours, then cooled to room temperature, and then processed, polished and cleaned to obtain the alkaline electrolytic cell plastic electrode frame.

[0062] Plastic frame material 2 Example: A plastic electrode frame for an alkaline electrolytic cell is provided, comprising the following components by weight: 100 parts polysulfone; 20 parts PFA resin; 5 parts bisphenol A type polycarbonate; 2 parts graphene oxide; 5 parts fluorosilane coupling agent; 5 parts chopped quartz fibers; 2 parts hollow glass microspheres; and 2 parts spherical silica powder. The PFA resin has a melt index of 14.3 g / 10 min; the bisphenol A type polycarbonate has a melt index of 3.9 g / 10 min; and the polysulfone has a melt index of 8.6 g / 10 min. The chopped quartz fibers have a length of 10-20 mm, the hollow glass microspheres have a particle size range of 50-80 μm, the spherical silica powder has a particle size range of 1.5-2.0 μm, the graphene oxide has a particle size of 10-20 μm, and the oxygen content is 45 at%. The preparation method of this plastic electrode frame for the alkaline electrolytic cell includes the following steps: 1) Weigh each raw material component according to the weight proportions and dry each raw material component; 2) The dried raw materials are added to a twin-screw extruder for melt blending. The melt-extruded material is granulated to obtain extruded granules, which are then dried. The extruder feed section temperature is 320℃, the intermediate section temperature is 350℃, the discharge section temperature is 360℃, the screw speed is 300 rpm, and the melt blending time is 5 minutes. 3) Add the dried extruded granules into the injection molding machine and use the injection molding process to prepare the pole frame preform; the temperature of the front section of the barrel is 330℃, the temperature of the middle section is 350℃, the temperature of the rear section is 370℃, the mold temperature is 180℃, and the injection pressure is 130MPa. 4) After demolding, the electrode frame blank is annealed at 160℃~180℃ for 8 hours, then cooled to room temperature, and then processed, polished and cleaned to obtain the alkaline electrolytic cell plastic electrode frame.

[0063] Plastic frame material 3 A plastic electrode frame for an alkaline electrolytic cell is provided, comprising the following components by weight: 100 parts polysulfone; 30 parts PFA resin; 15 parts bisphenol A type polycarbonate; 6 parts graphene oxide; 10 parts fluorosilane coupling agent; 20 parts chopped quartz fibers; 8 parts hollow glass microspheres; and 6 parts spherical silica powder. The PFA resin has a melt index of 18.0 g / 10 min; the bisphenol A type polycarbonate has a melt index of 5.9 g / 10 min; and the polysulfone has a melt index of 11.4 g / 10 min. The chopped quartz fibers have a length of 10-20 mm, the hollow glass microspheres have a particle size range of 50-80 μm, the spherical silica powder has a particle size range of 1.5-2.0 μm, the graphene oxide has a particle size of 10-20 μm, and the oxygen content is 62 at%. The preparation method of this plastic electrode frame for the alkaline electrolytic cell includes the following steps: 1) Weigh each raw material component according to the weight proportions and dry each raw material component; 2) Add the dried raw materials to a twin-screw extruder for melt blending. The melt-extruded material is then granulated to obtain extruded granules, which are then dried. The extruder feed section temperature is 300℃, the intermediate section temperature is 330℃, the discharge section temperature is 350℃, the screw speed is 150rpm, and the melt blending time is 3 minutes. 3) Add the dried extruded granules into the injection molding machine and use the injection molding process to prepare the pole frame preform; the temperature of the front section of the barrel is 310℃, the temperature of the middle section is 330℃, the temperature of the rear section is 350℃, the mold temperature is 150℃, and the injection pressure is 90MPa. 4) After demolding, the electrode frame blank is annealed at 160~180℃ for 3 hours, then cooled to room temperature, and then processed, polished and cleaned to obtain the alkaline electrolytic cell plastic electrode frame.

[0064] Plastic frame material 4 It is basically the same as plastic pole frame material 1, except that the melt index of the PFA resin used is 19.3 g / 10 min, the melt index of the bisphenol A type polycarbonate used is 7.2 g / 10 min, and the melt index of the polysulfone used is 14.5 g / 10 min.

[0065] Plastic frame material 5 It is basically the same as plastic pole frame material 1, except that the melt index of the PFA resin used is 12.6 g / 10 min, the melt index of the bisphenol A type polycarbonate used is 3.3 g / 10 min, and the melt index of the polysulfone used is 7.0 g / 10 min.

[0066] Plastic frame material 6 It is basically the same as plastic pole frame material 1, except that the length of the quartz short chopped fiber used is 5~10mm, the particle size range of the hollow glass microspheres used is 30~50μm, and the particle size range of the spherical silica powder used is 1.0~1.5μm.

[0067] Plastic frame material 7 It is basically the same as plastic pole frame material 1, except that the length of the quartz short chopped fiber used is 20~30mm, the particle size range of the hollow glass microspheres used is 100~150μm, and the particle size range of the spherical silica powder used is 2.0~2.5μm.

[0068] Plastic frame material D1 It is basically the same as plastic pole frame material 1, except that PFA resin is replaced with an equal amount of bisphenol A type polycarbonate.

[0069] Plastic frame material D2 It is basically the same as plastic pole frame material 1, except that bisphenol A type polycarbonate is replaced with an equal amount of PFA resin.

[0070] Plastic frame material D3 It is basically the same as plastic pole frame material 1, except that hollow glass microspheres are replaced with an equal amount of chopped quartz fibers.

[0071] Plastic frame material D4 It is basically the same as plastic pole frame material 1, except that the spherical silicon micro powder is replaced with an equal amount of short-cut quartz fibers.

[0072] Plastic frame material D5 It is basically the same as plastic pole frame material 1, except that it does not contain graphene oxide.

[0073] The performance of the alkaline electrolytic cell plastic electrode frame material obtained above was tested, and the results are shown in Table 2 below.

[0074] Hardness: Tested at 80°C. After heating the sample to the target temperature, the hardness test is performed immediately. Specifically, the Shore D hardness test is performed on the material according to ASTM D2240-15.

[0075] Tensile strength: Tested at 80°C. After heating the sample to the target temperature, the tensile strength test is performed immediately. The tensile strength test of the material is performed in accordance with ISO 527-2:2012.

[0076] High-temperature creep test: The long-term high-temperature stability of the material is tested according to ASTM D2990-17 at a temperature of 80°C to evaluate its deformation behavior under sustained load conditions.

[0077] Impact resistance: The cantilever beam notched impact test was conducted at a temperature of 80°C. After the sample was heated to the target temperature, the impact resistance test was conducted immediately. The impact resistance test of the material was carried out in accordance with ASTM D256.

[0078] In addition, the researchers also tested the material's resistance to strong alkali corrosion. According to ASTM D543, the samples were immersed in an alkaline solution at high temperature. The mass change and mechanical property retention rate before and after immersion were compared for evaluation. The results showed that the plastic pole frame material obtained above had excellent resistance to strong alkali corrosion at high temperature and could meet the requirements for long-term use of the product.

[0079] Table 2 Performance test results of alkali-plastic electrode frame materials

[0080] As shown in Table 2, the plastic electrode frame in this application uses polysulfone as the main material, combined with PFA resin and bisphenol A type polycarbonate. Furthermore, it employs quartz short-cut fibers of specific morphology and size, along with hollow glass microspheres and spherical silica powder as reinforcing materials. The resulting plastic electrode frame for the alkaline electrolyzer exhibits good strength, high-temperature resistance, and strong alkali corrosion resistance. In particular, it significantly improves the mechanical strength properties under 80℃ high-temperature conditions, such as hardness, tensile strength, high-temperature creep strain, and impact resistance, all of which reach high levels. This makes it highly suitable for the performance requirements of plastic electrode frames in multi-unit alkaline water electrolysis hydrogen production devices, thus giving it good market competitiveness.

[0081] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A process for preparing the plastic layer of an alkaline electrolytic cell electrode frame, characterized in that, The preparation process includes the following steps: S1. After cleaning the metal frame, perform surface roughening treatment; S2. After coating the surface of the metal pole frame with a silane coupling agent, it is cured to form an activation layer; S3. Mix and melt-blend the plastic composite material to obtain the coating material; S4. Place the metal pole frame into the mold, and inject the molten coating material into the mold cavity to form a continuous coating layer on the outer surface of the metal pole frame. S5. After cooling, demold to complete the preparation of the alkaline electrolytic cell electrode frame plastic layer.

2. The preparation process of the alkaline electrolytic cell electrode frame plastic layer according to claim 1, characterized in that, In step S2, the silane coupling agent is a fluorosilane coupling agent. The curing process includes heating the metal electrode frame treated with the fluorosilane coupling agent to 100-120°C for 60-120 minutes under a relative humidity of 30-50%, and then letting it stand at room temperature for at least 30 minutes after curing.

3. The preparation process of the alkaline electrolytic cell electrode frame plastic layer according to claim 1, characterized in that, Step S4 includes: preheating the metal electrode frame to 100~150°C and then placing it into the mold; melting the coating material and injecting it into the mold cavity to form a continuous coating layer on the outer surface of the metal electrode frame.

4. The preparation process of the alkaline electrolytic cell electrode frame plastic layer according to claim 1, characterized in that, The demolding process after cooling in step S5 includes a three-stage annealing process: the first stage annealing process, holding at 170~190℃ for 2~10 minutes; the second stage annealing process, holding at 130~150℃ for 30~60 minutes; and the third stage annealing process, holding at 70~90℃ for 10~20 minutes. After demolding, the product is allowed to cool naturally to room temperature.

5. The preparation process of the alkaline electrolytic cell electrode frame plastic layer according to claim 1, characterized in that, The coating material comprises the following components by weight: 100 parts polysulfone; 20-30 parts PFA resin; 5-15 parts bisphenol A polycarbonate; 2-6 parts graphene oxide; 5-10 parts fluorosilane coupling agent; 5-20 parts chopped quartz fibers; 2-8 parts hollow glass microspheres; and 2-6 parts spherical silica powder.

6. The preparation process of the alkaline electrolytic cell electrode frame plastic layer according to claim 5, characterized in that, The melt index of the PFA resin is 14-18 g / 10 min; and / or, The bisphenol A type polycarbonate has a melt index of 3.9~6 g / 10 min; and / or, The polysulfone has a melt index of 8~12 g / 10 min.

7. The preparation process of the alkaline electrolytic cell electrode frame plastic layer according to claim 5, characterized in that, The length of the quartz chopped fibers is 10~20mm; and / or, The hollow glass microspheres have a particle size range of 50~80μm; and / or, The spherical silica powder has a particle size range of 1.5~2.0 μm; and / or, The graphene oxide has a particle size of 10-20 μm and an oxygen content of 45-62 at.

8. The preparation process of the alkaline electrolytic cell electrode frame plastic layer according to claim 1, characterized in that, The surface roughening treatment in step S1 includes: using sandblasting, with 80~200 mesh quartz sand as the sandblasting medium, sandblasting pressure of 0.3~0.7MPa, sandblasting time of 10~30s, and the surface roughness after roughening treatment is 1.5~4.0μm.

9. The alkaline electrolytic cell electrode frame obtained by the preparation process according to any one of claims 1 to 8.

10. The application of the alkaline electrolytic cell electrode frame as described in claim 9 in alkaline electrolytic cell products.

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