A zinc-rich heavy-duty coating and a method for preparing the same

Abstract

This invention provides a zinc-rich heavy-duty anti-corrosion coating and its preparation method, belonging to the technical field of coating compositions. The method includes the following steps: mixing bisphenol A type liquid epoxy resin, zinc gluconate-supported modified GO, dispersant, defoamer, and a mixed solvent; sequentially adding fumed silica, polylactic acid@garnet composite powder, and zinc powder while stirring to obtain component A; separately mixing and stirring a polyamide curing agent and a curing accelerator to obtain component B; mixing and stirring component A and component B and defoaming to obtain the zinc-rich heavy-duty anti-corrosion coating. This invention can enhance the cathodic protection effect and the shielding and barrier ability against corrosive media, thereby improving long-term heavy-duty anti-corrosion performance.

Description

Technical Field

[0001] This invention relates to the field of coating composition technology, specifically to a zinc-rich heavy-duty anti-corrosion coating and its preparation method. Background Technology

[0002] Zinc-rich heavy-duty anti-corrosion coatings are widely used in long-term service environments such as bridges, marine engineering equipment, storage tanks, pipelines, and wind turbine towers because they provide cathodic protection to steel substrates through the sacrificial anodic effect of zinc powder and also act as a shielding barrier after film formation. Existing zinc-rich coatings typically use epoxy resin, polyurethane-modified resin, or inorganic silicate as the film-forming matrix, combined with a high zinc powder content to construct the anti-corrosion system. As service environments gradually shift from general atmospheric environments to high humidity, high salt spray, alternating wet and dry conditions, acid and alkali media, and complex mechanical stress environments, traditional zinc-rich coatings are increasingly revealing some common problems in practical applications: First, to ensure cathodic protection, a high content of zinc powder is usually required in the system. However, a high content of zinc powder can easily lead to increased system viscosity and the formation of pores, shrinkage cavities, and localized weak areas during film formation. Second, when the effective conductive contact between zinc powder particles is insufficient, the cathodic protection effect is difficult to maintain and stabilize. Some zinc powder is isolated and coated by resin, resulting in low utilization and limited effective protection efficiency despite a high zinc powder content. Third, high filler loading in zinc-rich systems can increase coating brittleness and reduce adhesion, thereby accelerating the penetration of corrosive media and weakening the long-term protective effect.

[0003] To improve the corrosion resistance of zinc-rich coatings, existing technologies typically employ two approaches: one is to enhance shielding and barrier capabilities and improve the local conductive network between zinc powder particles by introducing auxiliary components such as sheet-like fillers, nano-oxides, graphene oxides, carbon materials, or mineral fillers while maintaining a high zinc content. For example, patent application CN112961571A discloses an epoxy zinc-rich anti-corrosion coating containing a graphene oxide / black talc composite material and its preparation method. This coating provides corrosion protection through the two-dimensional sheet structure of the graphene oxide / black talc composite material. However, two-dimensional nanosheet materials are prone to stacking and agglomeration, and insufficient compatibility with the resin matrix interface may introduce local defects, affecting the effective barrier function. Another approach involves organic modification, coupling modification, or resin phase regulation of the zinc powder surface or inert filler surface to improve the dispersion stability and interfacial bonding ability of pigments and fillers in the resin. For example, patent application CN117070123A discloses a solvent-based zinc-rich heavy-duty anti-corrosion coating, which modifies flake-like zinc powder with a siloxane coupling agent to improve the dispersion stability and interfacial bonding ability of fillers in the resin. However, if the modified layer is too thick or the interfacial interaction is too strong, it may weaken the direct contact between zinc powder particles, affecting the continuity of cathodic protection and thus the final anti-corrosion effect of zinc-rich coating. In addition, although traditional fillers such as talc and mica powder have certain shielding and thickening effects, they often mainly serve as inert fillers, which can negatively affect the local conductive connectivity and transmission pathways of zinc powder particles, making it difficult to simultaneously achieve cathodic protection and shielding protection, thus affecting the anti-corrosion performance.

[0004] Therefore, there is a need to provide a zinc-rich heavy-duty anti-corrosion coating and its preparation method to solve the above-mentioned technical problems. Summary of the Invention

[0005] In view of this, the present invention provides a zinc-rich heavy-duty anti-corrosion coating and its preparation method, which can enhance the cathodic protection effect and the shielding and blocking ability against corrosive media, thereby improving the long-term heavy-duty anti-corrosion performance.

[0006] To achieve the above objectives, the present invention provides a zinc-rich heavy-duty anti-corrosion coating and its preparation method, comprising the following steps:

[0007] S1. Silk fibroin-modified graphene oxide was dispersed in anhydrous ethanol, magnetically stirred and ultrasonically treated, then zinc gluconate solution was added and mixed, heated, citric acid was added and the reaction was kept at the temperature, cooled to room temperature, washed, and freeze-dried to obtain zinc gluconate-supported modified GO.

[0008] S2. Dry the garnet waste, grind and sieve it, add it to the polylactic acid solution, stir and ultrasonically treat it, evaporate it under reduced pressure, vacuum dry it, and cool it to room temperature to obtain polylactic acid@garnet composite powder.

[0009] S3. Mix bisphenol A type liquid epoxy resin, zinc gluconate-supported modified GO, dispersant, defoamer and mixed solvent, then add fumed silica, polylactic acid@garnet composite powder and zinc powder in sequence and stir to obtain component A; separately mix polyamide curing agent and curing accelerator to obtain component B; mix component A and component B and defoam to obtain zinc-rich heavy-duty anti-corrosion coating.

[0010] This invention first modifies graphene oxide (GO) using silk fibroin, and then further loads it with zinc gluconate to obtain zinc gluconate-supported modified GO. The silk fibroin molecular chain contains polar groups such as amide and hydroxyl groups, which can adsorb and bind to the surface of graphene oxide through multi-site interactions. This improves the organophilicity of the graphene oxide surface, reduces the π-π stacking and aggregation tendency between sheets, and enhances its dispersion stability in epoxy resin systems and its interfacial compatibility with the resin matrix. The modified graphene oxide is more easily and uniformly distributed in coating systems, which is beneficial for improving the internal structure density of subsequent coatings and enhancing the barrier ability against corrosive media such as water, oxygen, and chloride ions. Furthermore, after loading with zinc gluconate, the polyhydroxyl and other polar groups in the gluconate group can interact with the oxygen-containing functional groups on the graphene oxide surface and the silk fibroin molecular chain through multi-site interactions, allowing zinc gluconate to be more stably distributed on the modified graphene oxide surface. The synergistic introduction of silk fibroin and zinc gluconate helps to weaken interlayer interactions and inhibit the recombination of zinc gluconate-supported modified GO, thus maintaining good dispersion uniformity in the epoxy resin system. Consequently, after coating curing, zinc gluconate-supported modified GO more easily constructs continuous and dense shielding pathways, extending the migration path of corrosive media to the substrate. The uniformly dispersed graphene oxide also plays a role in spatial connection and interface regulation between zinc powder particles in the coating, helping to improve the contact connectivity between zinc powder particles and promoting the formation of conductive / transfer pathways in the zinc-rich system. This facilitates the continued performance of the sacrificial anodic effect, thereby improving long-term corrosion resistance. Furthermore, when corrosive media penetrate or the coating is locally damaged, zinc gluconate can also play a certain auxiliary corrosion inhibition role in the interface region, working in conjunction with the aforementioned physical shielding and cathodic protection effects to jointly improve the long-term heavy-duty corrosion resistance of the final coating.

[0011] This invention first modifies garnet by coating it with polylactic acid (PLA), forming an organic-inorganic interface transition layer on the surface of the garnet particles. Garnet itself has high hardness, good chemical stability, and inert shielding properties, making it suitable as a rigid filler in coatings. Further PLA coating improves the compatibility and wetting / dispersion effect between the garnet particles and the epoxy resin continuous phase, reducing local agglomeration and stress concentration problems that easily occur when inorganic particles are directly filled. This results in a more uniform distribution of garnet in the coating, reducing micro-defects and weak interfacial areas caused by particle agglomeration, and alleviating local stress concentration after curing. Ultimately, this improves the interlayer bonding stability and impact resistance of the final coating. In addition, the interfacial coordination between garnet particles and the resin phase is improved after polylactic acid coating, which is more conducive to the filling, densification and shielding reinforcement in the system. It is less likely to cause significant interference to the effective contact between zinc powder particles due to the local aggregation of unmodified inorganic particles. This helps to avoid the adverse effects of the addition of inert fillers on the conductive transmission path and sacrificial anode effect of zinc-rich system. As a result, garnet not only improves the overall mechanical protection capability of the coating, but also helps to maintain its service stability in corrosive environments, thereby improving long-term heavy corrosion protection performance.

[0012] Optionally, the silk fibroin modified graphene oxide is obtained by adding graphene oxide to deionized water, ultrasonically treating it for 30-40 min, adding it to a silk fibroin dispersion, adjusting the pH to 9.8-10.2 by adding ammonia dropwise, magnetically stirring at room temperature for 18-20 h, washing with deionized water, centrifuging at 8000-10000 r / min for 10-15 min, collecting the precipitate, and freeze-drying it.

[0013] Adjusting the pH of the system to 9.8-10.2 with ammonia provides suitable weakly alkaline conditions for the interfacial bonding between silk fibroin and graphene oxide. This is beneficial for improving the adsorption uniformity and modification stability of silk fibroin on the graphene oxide surface, and reducing the tendency of silk fibroin aggregation and graphene oxide sheet agglomeration. As a result, the dispersion performance and compatibility with the resin matrix of the obtained silk fibroin-modified graphene oxide are improved.

[0014] Optionally, the silk fibroin dispersion is obtained by adding 40-50 parts by weight of silk fibroin to 1500-2000 parts by weight of deionized water and stirring magnetically for 40-60 minutes; the amount of graphene oxide in the silk fibroin-modified graphene oxide is 5-8 parts by weight and the amount of deionized water is 500-800 parts by weight.

[0015] Optionally, in step S1, 3-5 parts by weight of silk fibroin-modified graphene oxide are dispersed in 500-600 parts by weight of anhydrous ethanol, magnetically stirred for 30-40 minutes and ultrasonically treated for 20-30 minutes. Then, 400-600 parts by weight of a 2 wt% zinc gluconate solution are added and mixed. The mixture is placed in a single-necked round-bottom flask, heated to 70-75°C, 1-1.2 parts by weight of citric acid are added and the reaction is maintained for 8-10 hours. After cooling to room temperature, the mixture is washed 2-3 times with deionized water and anhydrous ethanol, and finally freeze-dried to obtain zinc gluconate-supported modified GO.

[0016] Optionally, the polylactic acid solution is obtained by adding 4-5 parts by weight of polylactic acid to 100-120 parts by weight of dichloromethane and stirring magnetically at 400-500 r / min for 50-80 min at room temperature.

[0017] Optionally, in step S2, 30-40 parts by weight of garnet waste are dried at 70-80℃ for 4-5 hours, ground and passed through a 300-mesh sieve, added to a polylactic acid solution under continuous stirring, stirred at 600-800 r / min for 30-40 minutes, then dispersed at 1300 r / min for 20-30 minutes, and ultrasonically treated for 10-20 minutes. The mixture is then transferred to a rotary evaporator, where dichloromethane is removed under reduced pressure in a water bath at 35-40℃, and vacuum dried at 50-55℃ for 8-10 hours. After cooling to room temperature, polylactic acid@garnet composite powder is obtained.

[0018] This invention employs reduced-pressure evaporation under a water bath at 35-40℃, which efficiently removes most of the solvent from the system at a lower temperature, avoiding the adverse effects of high-temperature evaporation on the polylactic acid (PLA) molecular chains and their coating properties. Simultaneously, it facilitates gentle concentration of the system, allowing PLA to adhere more uniformly to the surface of garnet particles, reducing particle agglomeration tendency, and lessening the burden on subsequent vacuum drying. Ultimately, this results in PLA@garnet composite powder with lower residual solvent and more uniform coating.

[0019] Optionally, component A is composed of bisphenol A type liquid epoxy resin, zinc gluconate supported modified GO, dispersant, defoamer and mixed solvent, premixed at 800 r / min for 5-8 min, then dispersed at 1500 r / min for 10-15 min, followed by the addition of fumed silica, and high-speed dispersion at 1800-2000 r / min for 30-40 min, then slowly adding polylactic acid@garnet composite powder, and continuing dispersion at 1000-1200 r / min for 10-15 min, then slowly adding zinc powder to the mixture in 4-5 portions, controlling the rotation speed at 400-500 r / min during the addition process, and continuing stirring at 650-700 r / min for 20-30 min after all the powder has been added.

[0020] In this invention, fumed silica can form a spatial network structure in the system, which improves the thixotropic properties and anti-settling ability of the system and slows down the settling trend of high-density zinc powder during storage and construction.

[0021] Optionally, the mixed solvent is xylene and n-butanol, wherein the mass ratio of xylene to n-butanol in the mixed solvent is 7:3; the zinc powder is obtained by pre-mixing 700-720 parts by mass of flake zinc powder and 60-80 parts by mass of spherical zinc powder evenly.

[0022] This invention employs a blend of flake-shaped and spherical zinc powder as the primary anti-corrosion pigment. The flake-shaped zinc powder facilitates the formation of a more continuous particle overlap structure within the coating, thereby improving the contact state between zinc powder particles in the zinc-rich system and enhancing the tortuosity of the corrosive medium's penetration path. The spherical zinc powder helps fill the gaps between the flake-shaped zinc powder particles, improving the density of the anti-corrosion pigment buildup. The blend, to a certain extent, balances conductive contact conditions, shielding effects, and coating density, which is beneficial for improving the effective utilization of zinc powder and the structural stability of the coating, thus enhancing the coating's long-term anti-corrosion capability against the metal substrate.

[0023] Preferably, the dispersant is BYK-9076; the defoamer is BYK-054.

[0024] Optionally, component B is obtained by mixing a polyamide curing agent and a curing accelerator and stirring at 300 r / min for 5 to 8 min;

[0025] The zinc-rich heavy-duty anti-corrosion coating is obtained by mixing component A and component B, stirring at 300~400 r / min for 8~10 min, and degassing at -0.08~-0.09 MPa for 5~8 min.

[0026] Preferably, the curing accelerator is DMP-30.

[0027] The present invention also provides a zinc-rich heavy-duty anti-corrosion coating, comprising component A and component B; component A comprises the following raw materials in parts by weight: 90-100 parts of bisphenol A type liquid epoxy resin, 3-6 parts of zinc gluconate supported modified GO, 2-5 parts of dispersant, 0.8-1.2 parts of defoamer, 10-20 parts of mixed solvent, 3-5 parts of fumed silica, 12-16 parts of polylactic acid@garnet composite powder, and 760-800 parts of zinc powder; component B comprises the following raw materials in parts by weight: 90-110 parts of polyamide curing agent and 0.8-1.2 parts of curing accelerator.

[0028] The zinc-rich heavy-duty anti-corrosion coating prepared by the present invention using the above-mentioned raw materials can form a synergistic effect among the epoxy resin matrix, zinc gluconate-supported modified GO, zinc powder, polylactic acid@garnet composite powder and fumed silica. While ensuring the cathodic protection function of the zinc-rich system, it further improves the shielding barrier ability, structural density and mechanical protection stability of the coating, thereby further enhancing the coating's long-term heavy-duty anti-corrosion protection capability for the metal substrate.

[0029] The above-described technical solution of the present invention has at least the following beneficial effects:

[0030] 1. This invention improves the dispersion stability and interfacial compatibility of graphene oxide in epoxy systems by synergistic modification of graphene oxide with silk fibroin and zinc gluconate, inhibits layer stacking, and enhances the coating density and shielding ability against corrosive media. At the same time, the zinc gluconate-supported modified GO helps to improve the contact connectivity between zinc powder particles, and together with the auxiliary corrosion inhibition effect of zinc gluconate, it improves the cathodic protection effect and long-term heavy corrosion resistance of zinc-rich coatings.

[0031] 2. This invention improves the compatibility and dispersion uniformity of garnet with epoxy resin by coating it with polylactic acid, reducing particle agglomeration and stress concentration, and improving the interlayer bonding stability and impact resistance of the coating. At the same time, it makes it more conducive to playing a filling, dense and shielding role, reducing the adverse effects on the conductive transmission path of zinc powder, thus taking into account both mechanical protection and long-term heavy corrosion protection performance. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are some embodiments of the present invention, and all other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0033] In the following examples and comparative examples, both the flake zinc powder and the spherical zinc powder were industrial-grade zinc powders, purchased from Hunan Xinweiling Metal New Material Technology Co., Ltd. The bisphenol A type liquid epoxy resin was purchased from Shandong Deyuan Epoxy Technology Co., Ltd. The fumed silica was purchased from Jinan Zhongbei Fine Chemical Co., Ltd. The garnet waste was almandine-type waste garnet abrasive, with almandine as the main mineral component, containing over 90 wt%.

[0034] Example 1

[0035] 40g of silk fibroin was added to 1500g of deionized water and magnetically stirred for 40min to obtain a silk fibroin dispersion. 5g of graphene oxide was added to 500g of deionized water and sonicated for 30min. Then, it was added to the silk fibroin dispersion, and ammonia was added dropwise to adjust the pH to 9.8. After magnetic stirring at room temperature for 18h, it was washed with deionized water and centrifuged at 8000r / min for 10min. The precipitate was collected and freeze-dried to obtain silk fibroin-modified graphene oxide. 3g of silk fibroin-modified graphene oxide was dispersed in 500g of anhydrous ethanol, magnetically stirred for 30min and sonicated for 20min. Then, 400g of 2wt% zinc gluconate solution was added and mixed. The mixture was placed in a single-necked round-bottom flask, heated to 70℃, 1g of citric acid was added, and the reaction was maintained at this temperature for 8h. After cooling to room temperature, it was washed twice with deionized water and anhydrous ethanol, and finally freeze-dried to obtain zinc gluconate-supported modified GO.

[0036] 4g of polylactic acid was added to 100g of dichloromethane and magnetically stirred at 400r / min for 50min at room temperature to obtain a polylactic acid solution. 30g of garnet waste was dried at 70℃ for 4h, ground and passed through a 300-mesh sieve, and added to the polylactic acid solution under continuous stirring. The mixture was stirred at 600r / min for 30min, then increased to 1300r / min for dispersion for 20min, and ultrasonically treated for 10min. The mixture was then transferred to a rotary evaporator and dichloromethane was removed under reduced pressure in a 35℃ water bath. The mixture was then vacuum dried at 50℃ for 8h and cooled to room temperature to obtain polylactic acid@garnet composite powder.

[0037] Zinc powder was obtained by pre-mixing 700g of flake zinc powder and 60g of spherical zinc powder evenly. 90g of bisphenol A type liquid epoxy resin (model E-51), 3g of zinc gluconate-supported modified GO, 2g of dispersant BYK-9076, 0.8g of defoamer BYK-054, and 10g of mixed solvent were mixed, with a xylene to n-butanol mass ratio of 7:3 in the mixed solvent. The mixture was first premixed at 800r / min for 5min, then dispersed at 1500r / min for 10min. Subsequently, 3g of fumed silica was added, and the mixture was dispersed at 1800r / min for 30min. Then, 12g of polylactic acid@garnet composite powder was slowly added, and the mixture was dispersed at 10... Disperse the mixture for 10 minutes at 00 r / min, then slowly add 760 g of zinc powder to the mixture in four portions, controlling the speed at 400 r / min during the addition. After all the powder has been added, continue stirring at 650 r / min for 20 minutes to obtain component A. Separately, mix 90 g of polyamide curing agent (CAS No.: 68410-23-1) and 0.8 g of curing accelerator DMP-30, and stir at 300 r / min for 5 minutes to obtain component B. Mix component A and component B, stir at 300 r / min for 8 minutes, and degas at -0.08 MPa for 5 minutes to obtain zinc-rich heavy-duty anti-corrosion coating.

[0038] Example 2

[0039] 45g of silk fibroin was added to 1800g of deionized water and magnetically stirred for 50min to obtain a silk fibroin dispersion. 6g of graphene oxide was added to 650g of deionized water and sonicated for 35min. Then, it was added to the silk fibroin dispersion, and ammonia was added dropwise to adjust the pH to 10.0. After magnetic stirring at room temperature for 19h, it was washed with deionized water and centrifuged at 9000r / min for 12min. The precipitate was collected and freeze-dried to obtain silk fibroin-modified graphene oxide. 4g of silk fibroin-modified graphene oxide was dispersed in 550g of anhydrous ethanol, magnetically stirred for 35min and sonicated for 25min. Then, 500g of 2wt% zinc gluconate solution was added and mixed. The mixture was placed in a single-necked round-bottom flask, heated to 73℃, 1.1g of citric acid was added, and the reaction was maintained at this temperature for 9h. After cooling to room temperature, it was washed three times with deionized water and anhydrous ethanol, and finally freeze-dried to obtain zinc gluconate-supported modified GO.

[0040] 4.5g of polylactic acid was added to 110g of dichloromethane and magnetically stirred at 450r / min for 60min at room temperature to obtain a polylactic acid solution. 35g of garnet waste was dried at 75℃ for 4.5h, ground and passed through a 300-mesh sieve, and added to the polylactic acid solution under continuous stirring. The mixture was stirred at 700r / min for 35min, then dispersed at 1300r / min for 25min, and ultrasonically treated for 15min. The mixture was then transferred to a rotary evaporator and dichloromethane was removed under reduced pressure in a 38℃ water bath. The mixture was then vacuum dried at 52℃ for 9h and cooled to room temperature to obtain polylactic acid@garnet composite powder.

[0041] Zinc powder was obtained by pre-mixing 710g of flake zinc powder and 70g of spherical zinc powder evenly. 95g of bisphenol A type liquid epoxy resin (model E-51), 4.5g of zinc gluconate-supported modified GO, 3.5g of dispersant BYK-9076, 1.0g of defoamer BYK-054, and 15g of mixed solvent were mixed, with a xylene to n-butanol mass ratio of 7:3 in the mixed solvent. The mixture was first pre-mixed at 800r / min for 6min, then dispersed at 1500r / min for 12min. Subsequently, 4g of fumed silica was added, and the mixture was dispersed at 1900r / min for 35min. Then, 14g of polylactic acid@garnet composite powder was slowly added, and the mixture was further dispersed at 1... Disperse the mixture for 12 minutes at 100 rpm, then slowly add 780 g of zinc powder to the mixture in 5 portions, controlling the speed at 450 rpm during the addition. After all the powder has been added, continue stirring at 680 rpm for 25 minutes to obtain component A. Separately, mix 100 g of polyamide curing agent (CAS No.: 68410-23-1) and 1.0 g of curing accelerator DMP-30, and stir at 300 rpm for 6 minutes to obtain component B. Mix component A and component B, stir at 350 rpm for 9 minutes, and degas at -0.085 MPa for 6 minutes to obtain zinc-rich heavy-duty anti-corrosion coating.

[0042] Example 3

[0043] 50g of silk fibroin was added to 2000g of deionized water and magnetically stirred for 60min to obtain a silk fibroin dispersion. 8g of graphene oxide was added to 800g of deionized water and sonicated for 40min. Then, it was added to the silk fibroin dispersion, and ammonia was added dropwise to adjust the pH to 10.2. After magnetic stirring at room temperature for 20h, it was washed with deionized water and centrifuged at 10000r / min for 15min. The precipitate was collected and freeze-dried to obtain silk fibroin-modified graphene oxide. 5g of silk fibroin-modified graphene oxide was dispersed in 600g of anhydrous ethanol, magnetically stirred for 40min and sonicated for 30min. Then, 600g of 2wt% zinc gluconate solution was added and mixed. The mixture was placed in a single-necked round-bottom flask, heated to 75℃, 1.2g of citric acid was added, and the reaction was maintained at this temperature for 10h. After cooling to room temperature, it was washed three times with deionized water and anhydrous ethanol, and finally freeze-dried to obtain zinc gluconate-supported modified GO.

[0044] 5g of polylactic acid was added to 120g of dichloromethane and magnetically stirred at 500r / min for 80min at room temperature to obtain a polylactic acid solution. 40g of garnet waste was dried at 80℃ for 5h, ground and passed through a 300-mesh sieve, and added to the polylactic acid solution under continuous stirring. The mixture was stirred at 800r / min for 40min, then increased to 1300r / min for dispersion for 30min, and ultrasonically treated for 20min. The mixture was then transferred to a rotary evaporator and dichloromethane was removed under reduced pressure in a 40℃ water bath. The mixture was then vacuum dried at 55℃ for 10h and cooled to room temperature to obtain polylactic acid@garnet composite powder.

[0045] Zinc powder was obtained by pre-mixing 720g of flake zinc powder and 80g of spherical zinc powder evenly. 100g of bisphenol A type liquid epoxy resin (model E-51), 6g of zinc gluconate-supported modified GO, 5g of dispersant BYK-9076, 1.2g of defoamer BYK-054, and 20g of mixed solvent were mixed, with a xylene to n-butanol mass ratio of 7:3 in the mixed solvent. The mixture was first pre-mixed at 800 rpm for 8 min, then dispersed at 1500 rpm for 15 min. Subsequently, 5g of fumed silica was added, and the mixture was dispersed at 2000 rpm for 40 min. Then, 16g of polylactic acid@garnet composite powder was slowly added, and the mixture was dispersed at 120°C. Continue dispersing at 0 r / min for 15 min, then slowly add 800 g of zinc powder to the mixture in 5 portions, controlling the rotation speed at 500 r / min during the addition process. After all the powder has been added, continue stirring at 700 r / min for 30 min to obtain component A. Separately, mix 110 g of polyamide curing agent (CAS No.: 68410-23-1) and 1.2 g of curing accelerator DMP-30, and stir at 300 r / min for 8 min to obtain component B. Mix component A and component B, stir at 400 r / min for 10 min, and degas at -0.09 MPa for 8 min to obtain zinc-rich heavy-duty anti-corrosion coating.

[0046] Example 4

[0047] 49g of silk fibroin was added to 1950g of deionized water and magnetically stirred for 58min to obtain a silk fibroin dispersion. 7.5g of graphene oxide was added to 760g of deionized water and sonicated for 39min. Then, it was added to the silk fibroin dispersion, and ammonia was added dropwise to adjust the pH to 10.15. After magnetic stirring at room temperature for 19.5h, it was washed with deionized water and centrifuged at 9800r / min for 14min. The precipitate was collected and freeze-dried to obtain silk fibroin-modified graphene oxide. 4.8g of silk fibroin-modified graphene oxide was dispersed in 590g of anhydrous ethanol, magnetically stirred for 38min and sonicated for 29min. Then, 580g of 2wt% zinc gluconate solution was added and mixed. The mixture was placed in a single-necked round-bottom flask, heated to 74.5℃, 1.18g of citric acid was added, and the reaction was maintained at this temperature for 9.8h. After cooling to room temperature, it was washed three times with deionized water and anhydrous ethanol, and finally freeze-dried to obtain zinc gluconate-supported modified GO.

[0048] 4.9 g of polylactic acid was added to 118 g of dichloromethane and magnetically stirred at 490 r / min for 75 min at room temperature to obtain a polylactic acid solution. 39 g of garnet waste was dried at 79 °C for 4.8 h, ground and passed through a 300 mesh sieve, and added to the polylactic acid solution under continuous stirring. The mixture was stirred at 780 r / min for 38 min, then dispersed at 1300 r / min for 29 min, and ultrasonically treated for 18 min. The mixture was then transferred to a rotary evaporator and dichloromethane was removed under reduced pressure in a water bath at 39.5 °C. The mixture was then vacuum dried at 54 °C for 9.8 h and cooled to room temperature to obtain polylactic acid@garnet composite powder.

[0049] Zinc powder was obtained by pre-mixing 718g of flake zinc powder and 78g of spherical zinc powder evenly. 99g of bisphenol A type liquid epoxy resin (model E-51), 5.5g of zinc gluconate-supported modified GO, 4.5g of dispersant BYK-9076, 1.15g of defoamer BYK-054, and 19g of mixed solvent were mixed, with a xylene to n-butanol mass ratio of 7:3 in the mixed solvent. The mixture was first premixed at 800r / min for 7.5min, then increased to 1500r / min for 14min. Subsequently, 4.8g of fumed silica was added, and the mixture was dispersed at 1980r / min for 39min. Finally, 15.5g of polylactic acid@garnet composite powder was slowly added, and the mixture was dispersed at 1... Disperse the mixture for 14 minutes at 180 rpm, then slowly add 796 g of zinc powder to the mixture in 5 portions, controlling the speed at 490 rpm during the addition. After all the powder has been added, continue stirring at 695 rpm for 28 minutes to obtain component A. Separately, mix 108 g of polyamide curing agent (CAS No.: 68410-23-1) and 1.15 g of curing accelerator DMP-30, and stir at 300 rpm for 7.5 minutes to obtain component B. Mix component A and component B, stir at 390 rpm for 9.8 minutes, and degas at -0.089 MPa for 7.5 minutes to obtain zinc-rich heavy-duty anti-corrosion coating.

[0050] Example 5

[0051] 47g of silk fibroin was added to 1900g of deionized water and magnetically stirred for 55min to obtain a silk fibroin dispersion. 6.8g of graphene oxide was added to 700g of deionized water and sonicated for 37min. Then, it was added to the silk fibroin dispersion, and ammonia was added dropwise to adjust the pH to 10.1. After magnetic stirring at room temperature for 19.2h, it was washed with deionized water and centrifuged at 9500r / min for 13min. The precipitate was collected and freeze-dried to obtain silk fibroin-modified graphene oxide. 4.5g of silk fibroin-modified graphene oxide was dispersed in 570g of anhydrous ethanol, magnetically stirred for 37min and sonicated for 28min. Then, 540g of 2wt% zinc gluconate solution was added and mixed. The mixture was placed in a single-necked round-bottom flask, heated to 74℃, 1.15g of citric acid was added, and the reaction was maintained at this temperature for 9.5h. After cooling to room temperature, it was washed three times with deionized water and anhydrous ethanol, and finally freeze-dried to obtain zinc gluconate-supported modified GO.

[0052] 4.7g of polylactic acid was added to 115g of dichloromethane and magnetically stirred at 470r / min for 70min at room temperature to obtain a polylactic acid solution. 37g of garnet waste was dried at 78℃ for 4.7h, ground and passed through a 300-mesh sieve, and added to the polylactic acid solution under continuous stirring. The mixture was stirred at 750r / min for 37min, then dispersed at 1300r / min for 27min, and ultrasonically treated for 17min. The mixture was then transferred to a rotary evaporator and dichloromethane was removed under reduced pressure in a 39℃ water bath. The mixture was then vacuum dried at 53℃ for 9.5h and cooled to room temperature to obtain polylactic acid@garnet composite powder.

[0053] Zinc powder was obtained by pre-mixing 715g of flake zinc powder and 75g of spherical zinc powder evenly. 98g of bisphenol A type liquid epoxy resin (model E-51), 5g of zinc gluconate-supported modified GO, 4g of dispersant BYK-9076, 1.1g of defoamer BYK-054, and 18g of mixed solvent were mixed, with a xylene to n-butanol mass ratio of 7:3 in the mixed solvent. The mixture was first pre-mixed at 800r / min for 7min, then increased to 1500r / min for 13min, followed by the addition of 4.5g of fumed silica and high-speed dispersion at 1950r / min for 37min. Finally, 15g of polylactic acid@garnet composite powder was slowly added and dispersed at 115... Disperse the mixture for 13 minutes at 0 rpm, then slowly add 790 g of zinc powder to the mixture in 5 portions, controlling the speed at 470 rpm during the addition. After all the powder has been added, continue stirring at 690 rpm for 27 minutes to obtain component A. Separately, mix 105 g of polyamide curing agent (CAS No.: 68410-23-1) and 1.1 g of curing accelerator DMP-30, and stir at 300 rpm for 7 minutes to obtain component B. Mix component A and component B, stir at 380 rpm for 9.5 minutes, and degas at -0.088 MPa for 7 minutes to obtain zinc-rich heavy-duty anti-corrosion coating.

[0054] Example 6

[0055] 42g of silk fibroin was added to 1600g of deionized water and magnetically stirred for 45min to obtain a silk fibroin dispersion. 5.5g of graphene oxide was added to 580g of deionized water and sonicated for 32min. Then, it was added to the silk fibroin dispersion, and ammonia was added dropwise to adjust the pH to 9.9. After magnetic stirring at room temperature for 18.5h, it was washed with deionized water and centrifuged at 8500r / min for 11min. The precipitate was collected and freeze-dried to obtain silk fibroin-modified graphene oxide. 3.5g of silk fibroin-modified graphene oxide was dispersed in 520g of anhydrous ethanol, magnetically stirred for 32min and sonicated for 22min. Then, 450g of 2wt% zinc gluconate solution was added and mixed. The mixture was placed in a single-necked round-bottom flask, heated to 71℃, 1.05g of citric acid was added, and the reaction was maintained at this temperature for 8.5h. After cooling to room temperature, it was washed twice with deionized water and anhydrous ethanol, and finally freeze-dried to obtain zinc gluconate-supported modified GO.

[0056] 4.2g of polylactic acid was added to 105g of dichloromethane and magnetically stirred at 430r / min for 55min at room temperature to obtain a polylactic acid solution. 32g of garnet waste was dried at 72℃ for 4.2h, ground and passed through a 300-mesh sieve, and added to the polylactic acid solution under continuous stirring. The mixture was stirred at 650r / min for 32min, then dispersed at 1300r / min for 22min, and ultrasonically treated for 12min. The mixture was then transferred to a rotary evaporator and dichloromethane was removed under reduced pressure in a 36℃ water bath. The mixture was then vacuum dried at 51℃ for 8.5h and cooled to room temperature to obtain polylactic acid@garnet composite powder.

[0057] Zinc powder was obtained by pre-mixing 705g of flake zinc powder and 65g of spherical zinc powder evenly. 92g of bisphenol A type liquid epoxy resin (model E-51), 4g of zinc gluconate-supported modified GO, 3g of dispersant BYK-9076, 0.9g of defoamer BYK-054, and 12g of mixed solvent were mixed, with a xylene to n-butanol mass ratio of 7:3 in the mixed solvent. The mixture was first premixed at 800r / min for 6min, then dispersed at 1500r / min for 11min. Subsequently, 3.5g of fumed silica was added, and the mixture was dispersed at 1850r / min for 32min. Then, 13g of polylactic acid@garnet composite powder was slowly added, and the mixture was dispersed at 105... Disperse the mixture for 11 minutes at 0 rpm, then slowly add 770 g of zinc powder to the mixture in four portions, controlling the stirring speed at 430 rpm during the addition. After all the powder has been added, continue stirring at 670 rpm for 22 minutes to obtain component A. Separately, mix 95 g of polyamide curing agent (CAS No.: 68410-23-1) and 0.9 g of curing accelerator DMP-30, and stir at 300 rpm for 6 minutes to obtain component B. Mix component A and component B, stir at 320 rpm for 8.5 minutes, and degas at -0.082 MPa for 6 minutes to obtain zinc-rich heavy-duty anti-corrosion coating.

[0058] The present invention also includes comparative examples and related experiments.

[0059] Comparative Example 1

[0060] Compared with Example 2, the only difference is that graphene oxide is used instead of zinc gluconate-supported modified GO, while the other preparation methods and proportions are completely the same, and a zinc-rich heavy-duty anti-corrosion coating is finally obtained.

[0061] Comparative Example 2

[0062] Compared with Example 2, the only difference is that graphene oxide is used instead of silk fibroin-modified graphene oxide, while the other preparation methods and proportions are completely the same, and a zinc-rich heavy-duty anti-corrosion coating is finally obtained.

[0063] Comparative Example 3

[0064] Compared with Example 2, the only difference is that garnet waste is used instead of polylactic acid@garnet composite powder. The other preparation methods and proportions are completely the same, and the final product is a zinc-rich heavy-duty anti-corrosion coating.

[0065] Performance testing

[0066] I. Performance tests were conducted on the zinc-rich heavy-duty anti-corrosion coatings prepared in Examples 1-6 and Comparative Examples 1-3. The viscosity of the coatings was tested according to GB / T9751.1-2008 "Determination of viscosity by rotational viscometer for paints and varnishes - Part 1: Cone-plate viscometer operating at high shear rates", and the density was tested according to GB / T6750-2007 "Determination of density of paints and varnishes - Specific gravity bottle method". Specific test results are shown in Table 1.

[0067] Table 1

[0068]

[0069] As shown in Table 1, the zinc-rich heavy-duty anti-corrosion coatings prepared in Examples 1-6 all exhibited suitable viscosity and density under mixed application conditions, indicating that the system of the present invention still has good application adaptability under high zinc content conditions. In contrast, the viscosity of Comparative Examples 1-3 was generally higher, indicating that when the synergistic effect of zinc gluconate-supported modified GO or polylactic acid@garnet composite powder is lacking, the particle dispersion and interfacial compatibility within the system are poor, and the rheological properties of the coatings under application conditions are not as stable as those of the embodiments of the present invention.

[0070] II. Basic performance testing of the coating:

[0071] (1) Test plate preparation: Q235 carbon steel sandblasting plate was selected as the test plate, and degreasing, rust removal, surface cleaning and drying were carried out in sequence for later use.

[0072] (2) Coating preparation: The zinc-rich heavy-duty anti-corrosion coatings prepared in Examples 1-6 and Comparative Examples 1-3 were applied to the surface of the test plate by scraping, and the dry film thickness was controlled to be (80±5) μm. After curing at room temperature for 7 days, subsequent tests were carried out.

[0073] Coating adhesion was tested according to GB / T9286-2021 "Cross-cut test for paints and varnishes", hardness was tested according to GB / T6739-2022 "Determination of hardness of paint film by pencil method for paints and varnishes", flexibility was tested according to GB / T1731-2020 "Determination of flexibility of paint film and putty film", and impact resistance was tested according to GB / T1732-2020 "Determination of impact resistance of paint film". Specific performance test results are shown in Table 2.

[0074] Table 2

[0075]

[0076] As shown in Table 2, the coatings obtained in Examples 1-6 all exhibit good adhesion, hardness, flexibility, and impact resistance, indicating that the zinc-rich epoxy protective system constructed in this invention not only ensures strong interfacial bonding but also maintains a certain level of toughness and impact resistance. In contrast, the adhesion, flexibility, and impact resistance of Comparative Examples 1-3 all decreased to varying degrees. Comparative Example 1, due to the use of graphene oxide instead of zinc gluconate-supported modified GO, lacked the modification of silk fibroin and the loading of zinc gluconate, resulting in a significant decrease in adhesion. Comparative Example 3, due to the use of garnet waste instead of polylactic acid@garnet composite powder, also showed a significant decrease in adhesion, flexibility, and impact resistance, with the most significant decreases in flexibility and impact resistance.

[0077] III. Conductivity and Protection Performance Testing: First, the conductivity / resistance test was conducted according to GB / T33328-2016 "Determination of Conductivity and Resistance of Paints and Varnishes". Then, using an electrochemical test, the coating samples prepared in Examples 1-6 and Comparative Examples 1-3 were immersed in a 3.5% NaCl solution, and the cathodic protection period was tested electrochemically. The cathodic protection failure criterion was defined as the open-circuit potential of the coating sample relative to the saturated calomel electrode exceeding -0.85V, and the time corresponding to reaching this criterion was recorded as the cathodic protection period. Furthermore, the impedance value of the coating sample in the low-frequency region (0.01Hz) was tested when cathodic protection failure occurred. Specific test results are shown in Table 3.

[0078] Table 3

[0079]

[0080] As shown in Table 3, the coatings obtained in Examples 1-6 generally exhibit lower dry film resistance, longer cathodic protection period, and higher low-frequency impedance values. This indicates that the present invention can maintain a relatively continuous electron transport path in the zinc-rich system while also maintaining a strong barrier against corrosive media. In contrast, the dry film resistance of Comparative Examples 1-3 is significantly increased, while the cathodic protection period is shortened and the low-frequency impedance value decreases. Among them, Comparative Example 1, which uses only ordinary graphene oxide, has the highest dry film resistance, the shortest cathodic protection period, and the lowest impedance value at 0.01 Hz in the low-frequency region when cathodic protection fails. This indicates that the unmodified graphene oxide has poor dispersion, affecting the conductive network and shielding performance. Similarly, Comparative Example 3, which directly uses garnet waste, also shows a significantly increased dry film resistance and a significantly decreased cathodic protection period.

[0081] IV. Corrosion Resistance Test:

[0082] (1) Neutral salt spray test: The coating samples obtained in Examples 1-6 and Comparative Examples 1-3 were scratched on the coating surface using a scribing tool with a width of 0.5 mm. Then, a neutral salt spray test was conducted in accordance with GB / T10125-2021 "Civilization Test in Artificial Atmosphere" for 1000 h. After the test, the corrosion spread of the scratched area of ​​the coating was observed and the average corrosion width was measured.

[0083] (2) Salt water immersion test: The coating samples obtained in Examples 1-6 and Comparative Examples 1-3 were tested according to GB / T9274-1988 "Determination of resistance to liquid media for paints and varnishes". They were immersed in 3.5wt% NaCl aqueous solution for 30 days. After taking them out, the coating surface was observed to see if there were any phenomena such as blistering, loss of gloss, rust and peeling.

[0084] The specific test results are shown in Table 4.

[0085] Table 4

[0086]

[0087] As shown in Table 4, after 1000 hours of neutral salt spray testing, the average corrosion width of the zinc-rich heavy-duty anti-corrosion coating samples prepared in Examples 1-6 was controlled between 1.2 and 2.0 mm. Furthermore, after immersion in 3.5 wt% NaCl solution for 30 days, no significant changes in appearance were observed. This indicates that the coatings obtained in the embodiments of the present invention can maintain good structural integrity and protective stability under salt spray corrosion and brine immersion environments, exhibiting excellent corrosion resistance. In contrast, the corrosion resistance of Comparative Examples 1-3 was significantly reduced. Comparative Example 1 showed an average corrosion width of 6.8 mm after 1000 hours of neutral salt spray testing. After immersion in 3.5 wt% NaCl solution for 30 days, it exhibited significant blistering, rusting, and localized peeling, indicating that the use of ordinary graphene oxide had poor dispersibility and lost the auxiliary corrosion inhibition ability of zinc gluconate, resulting in a significant decrease in overall protective effect. Comparative Example 2 did not use silk fibroin modification and directly loaded zinc gluconate, so its corrosion resistance was also not very good. Comparative Example 3 did not use polylactic acid to coat and modify garnet, which led to a significant increase in the salt spray corrosion spread width, and obvious blistering, localized rusting, and peeling after immersion in salt water.

[0088] In summary, this invention, through the synergistic effect of zinc gluconate-supported modified GO, polylactic acid@garnet composite powder, and zinc powder, enhances the cathodic protection effect of the zinc-rich system while further improving the coating's barrier ability against corrosive media and structural stability. This significantly reduces the degree of corrosion spread under salt spray conditions and improves the appearance retention under salt water immersion conditions, demonstrating excellent long-term heavy-duty anti-corrosion performance.

[0089] The above are preferred embodiments of the present invention. Those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for producing a zinc-rich heavy-duty coating material, characterized by, Includes the following steps: S1. Silk fibroin-modified graphene oxide was dispersed in anhydrous ethanol, magnetically stirred and ultrasonically treated, then zinc gluconate solution was added and mixed, heated, citric acid was added and the reaction was kept at the temperature, cooled to room temperature, washed, and freeze-dried to obtain zinc gluconate-supported modified GO. S2. Dry the garnet waste, grind and sieve it, add it to the polylactic acid solution, stir and ultrasonically treat it, evaporate it under reduced pressure, vacuum dry it, and cool it to room temperature to obtain polylactic acid@garnet composite powder. S3. Mix the following raw materials in parts by weight: 90-100 parts of bisphenol A type liquid epoxy resin, 3-6 parts of zinc gluconate-supported modified GO, 2-5 parts of dispersant, 0.8-1.2 parts of defoamer, and 10-20 parts of mixed solvent. Then, add 3-5 parts of fumed silica, 12-16 parts of polylactic acid@garnet composite powder, and 760-800 parts of zinc powder and stir to obtain component A. Separately, mix the following raw materials in parts by weight: 90-110 parts of polyamide curing agent and 0.8-1.2 parts of curing accelerator to obtain component B. Mix component A and component B, stir and degas to obtain zinc-rich heavy-duty anti-corrosion coating.

2. The method for preparing a zinc-rich heavy-duty coating according to claim 1, characterized in that, The silk fibroin-modified graphene oxide was prepared by adding graphene oxide to deionized water, ultrasonicating for 30-40 minutes, adding it to a silk fibroin dispersion, adjusting the pH to 9.8-10.2 by adding ammonia dropwise, magnetically stirring at room temperature for 18-20 hours, washing with deionized water, centrifuging at 8000-10000 r / min for 10-15 minutes, collecting the precipitate, and freeze-drying.

3. The method of claim 2, wherein the zinc-rich heavy-duty coating is prepared by mixing zinc powder, a binder, a solvent, and a curing agent. The silk fibroin dispersion is obtained by adding 40-50 parts by weight of silk fibroin to 1500-2000 parts by weight of deionized water and stirring magnetically for 40-60 minutes; the amount of graphene oxide in the silk fibroin modified graphene oxide is 5-8 parts by weight and the amount of deionized water is 500-800 parts by weight.

4. The method for preparing a zinc-rich heavy-duty anti-corrosion coating according to claim 1, characterized in that, In step S1, 3-5 parts by weight of silk fibroin-modified graphene oxide are dispersed in 500-600 parts by weight of anhydrous ethanol, magnetically stirred for 30-40 min and ultrasonically treated for 20-30 min. Then, 400-600 parts by weight of 2 wt% zinc gluconate solution are added and mixed. The mixture is placed in a single-necked round-bottom flask, heated to 70-75°C, 1-1.2 parts by weight of citric acid are added and the reaction is maintained for 8-10 h. After cooling to room temperature, the mixture is washed 2-3 times with deionized water and anhydrous ethanol, and finally freeze-dried to obtain zinc gluconate-supported modified GO.

5. The method for preparing a zinc-rich heavy-duty anti-corrosion coating according to claim 1, characterized in that, The polylactic acid solution is obtained by adding 4-5 parts by weight of polylactic acid to 100-120 parts by weight of dichloromethane and stirring magnetically at 400-500 r / min for 50-80 min at room temperature.

6. The method for preparing a zinc-rich heavy-duty anti-corrosion coating according to claim 1, characterized in that, In step S2, 30-40 parts by weight of garnet waste are dried at 70-80℃ for 4-5 hours, ground and passed through a 300-mesh sieve, and then added to a polylactic acid solution under continuous stirring. The mixture is stirred at 600-800 r / min for 30-40 minutes, then dispersed at 1300 r / min for 20-30 minutes, and ultrasonically treated for 10-20 minutes. The mixture is then transferred to a rotary evaporator and dichloromethane is removed under reduced pressure in a water bath at 35-40℃. The mixture is then vacuum dried at 50-55℃ for 8-10 hours and cooled to room temperature to obtain polylactic acid@garnet composite powder.

7. The method for preparing a zinc-rich heavy-duty anti-corrosion coating according to claim 1, characterized in that, Component A is composed of bisphenol A type liquid epoxy resin, zinc gluconate supported modified GO, dispersant, defoamer and mixed solvent. It is premixed at 800 r / min for 5-8 min, then dispersed at 1500 r / min for 10-15 min. Fumed silica is then added and dispersed at 1800-2000 r / min for 30-40 min. Polylactic acid@garnet composite powder is then slowly added and dispersed at 1000-1200 r / min for 10-15 min. Zinc powder is then slowly added to the mixture in 4-5 portions, with the stirring speed controlled at 400-500 r / min during the addition. After all the zinc powder has been added, the mixture is stirred at 650-700 r / min for 20-30 min to obtain the final product.

8. The method for preparing a zinc-rich heavy-duty anti-corrosion coating according to claim 1, characterized in that, The mixed solvent is xylene and n-butanol, wherein the mass ratio of xylene to n-butanol in the mixed solvent is 7:3; the zinc powder is obtained by pre-mixing 700-720 parts by mass of flake zinc powder and 60-80 parts by mass of spherical zinc powder evenly.

9. The method for preparing a zinc-rich heavy-duty anti-corrosion coating according to claim 1, characterized in that, Component B is obtained by mixing a polyamide curing agent and a curing accelerator and stirring at 300 r / min for 5 to 8 min. The zinc-rich heavy-duty anti-corrosion coating is obtained by mixing component A and component B, stirring at 300~400 r / min for 8~10 min, and degassing at -0.08~-0.09 MPa for 5~8 min.

10. A zinc-rich heavy-duty anti-corrosion coating, characterized in that, The coating is prepared using the method described in any one of claims 1 to 9, comprising component A and component B. Component A comprises the following raw materials in parts by weight: 90-100 parts of bisphenol A type liquid epoxy resin, 3-6 parts of zinc gluconate-supported modified GO, 2-5 parts of dispersant, 0.8-1.2 parts of defoamer, 10-20 parts of mixed solvent, 3-5 parts of fumed silica, 12-16 parts of polylactic acid@garnet composite powder, and 760-800 parts of zinc powder. Component B comprises the following raw materials in parts by weight: 90-110 parts of polyamide curing agent and 0.8-1.2 parts of curing accelerator.

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