Modified flaky zinc powder, modification method, anticorrosive paint and preparation method thereof

Abstract

This application relates to the field of powder metallurgy technology, and particularly to a modified flake zinc powder, a modification method, an anti-corrosion coating, and a preparation method thereof. The modification method involves stirring flake zinc powder at a speed of 10-40 r / min, spraying an atomized modified dispersion onto the powder during stirring, transferring the flake zinc powder to a horizontal ball mill after atomization, using glass beads as a grinding aid, and dispersing it at a speed of 40-120 r / min for 1-3 hours. The resulting modified flake zinc powder is obtained after sieving. The modified dispersion includes a dispersant and a modifier, wherein the modifier is selected from at least one of silane coupling agents, titanate coupling agents, and fluorocarbon surfactants. The solution provided in this application, through a composite process of atomized coating and dry dispersion, achieves uniform and controllable adsorption of the modifier on the surface of the flake zinc powder, significantly improving the effective utilization rate of the modifier, reducing the amount of modifier and diluent consumed from the source, and producing a modified flake zinc powder with both low oil absorption value and high dispersibility.

Description

Technical Field

[0001] This application relates to the field of powder metallurgy technology, and in particular to a modified flake zinc powder, a modification method, an anti-corrosion coating, and a preparation method thereof. Background Technology

[0002] With increasingly stringent global environmental regulations restricting volatile organic compound (VOC) emissions from anti-corrosion coatings, long-lasting anti-corrosion coatings with low VOC content and high solids have become a core direction for industry development. Zinc powder coatings, due to their unique electrochemical sacrificial anodic protection mechanism and physical barrier effect, have significant application value in the field of steel structure corrosion protection. Among them, flake zinc powder exhibits significant advantages over traditional spherical zinc powder: its higher specific surface area allows the coating to form a dense, overlapping structure, effectively improving corrosion resistance; this structure supports thick-coating processes without cracking, while significantly reducing zinc powder consumption, better meeting the long-lasting corrosion protection requirements of high-solids coatings. However, the high specific surface area of ​​flake zinc powder leads to enhanced surface polarity, making it prone to particle agglomeration and poor dispersion uniformity in high-solids coating systems, severely restricting its practical application in low-VOC coatings. To overcome this defect, surface modification treatment must be performed on flake zinc powder to weaken surface polarity and enhance interfacial bonding with the resin matrix, thereby meeting the environmental regulations for high-performance anti-corrosion coatings.

[0003] In existing technologies, the modification of flake zinc powder mainly relies on wet processes: flake zinc powder is dispersed in a large amount of organic solvent medium, a modifier is added and stirred for coating, followed by filtration, drying, and crushing to obtain the modified product. This process has significant limitations. First, to ensure sufficient contact between the modifier and zinc powder particles, an excessive amount of organic solvent must be used as a dispersion carrier, resulting in an excessively high overall modifier ratio. However, the actual proportion of active ingredients effectively adsorbed onto the zinc powder surface is extremely low, leading to a double waste of resources for both the modifier and the organic solvent. Second, the solvent-containing waste generated by the wet process is highly toxic, and subsequent treatment is complex and costly. If attempts are made to recycle the organic solvent, residual impurities will interfere with the modification reaction process, causing fluctuations and uncontrollability in the modification effect, making it difficult to achieve mass production of stable modified flake zinc powder. These defects seriously hinder the industrialization and application of low-VOCs, high-solids anti-corrosion coatings.

[0004] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0005] One of the purposes of this application is to provide a method for modifying flake zinc powder to avoid the shortcomings of the prior art. By adopting a composite process of atomization coating and dry dispersion, the modifier is uniformly and controllably adsorbed on the surface of the flake zinc powder, which can significantly improve the effective utilization rate of the modifier, reduce the amount of modifier and diluent consumption from the source, and the modified flake zinc powder prepared has both low oil absorption value and high dispersibility.

[0006] The second objective of this application is to provide a sheet-like zinc powder.

[0007] The third objective of this application is to provide an anti-corrosion coating.

[0008] The fourth objective of this application is to provide a method for preparing an anti-corrosion coating.

[0009] One of the objectives of this application is to achieve the following technical solution: A method for modifying flake zinc powder is provided, comprising the following steps: The flaky zinc powder was stirred at a speed of 10~40 r / min. During the stirring process, the modified dispersion was sprayed onto it. After atomization, the flaky zinc powder was transferred to a horizontal ball mill and dispersed for 1~3 hours at a speed of 40~120 r / min using glass beads as a grinding aid. After sieving, the modified flaky zinc powder was obtained. The modified dispersion includes a dispersant and a modifier, wherein the modifier is selected from at least one of silane coupling agents, titanate coupling agents, and fluorocarbon surfactants.

[0010] In some embodiments, the amount of the modified dispersion is 0.5% to 4% of the weight of the flake zinc powder, and the mass ratio of the dispersant to the modifier is 1:(1 to 3).

[0011] In some embodiments, the step of stirring the flake zinc powder at a speed of 10-40 r / min, and spraying the atomized modified dispersion onto it during the stirring process, specifically includes: Add the flake zinc powder to the conical double ribbon mixer and stir at a speed of 10~40 r / min. During the stirring process, spray the modified dispersion liquid into the flake zinc powder through the atomizing nozzle of the conical double ribbon mixer at a pressure of 0.1~0.4 MPa for 8~25 min. Then continue stirring at a speed of 25 r / min for 10 minutes.

[0012] In some embodiments, the D50 particle size of the flake zinc powder is 5~45μm and the zinc content is >88%; the particle size of the glass beads is 3~10mm and the mass ratio of glass beads to flake zinc powder is (4~10):1.

[0013] In some embodiments, the modified dispersion further includes a diluent, the amount of which is 10% to 30% of the total weight of the modified dispersion.

[0014] The modification method for flake zinc powder provided in this application has the following beneficial effects: (1) The modification method of the flake zinc powder provided in this application, by precisely controlling the synergistic matching relationship between the atomizing spray pressure, flow rate and stirring speed, enables the modifier to form a coating layer on the surface of the flake zinc powder, which can effectively reduce the surface polarity of the zinc powder and significantly improve the dispersion stability and interfacial compatibility of the flake zinc powder in the high solids epoxy anti-corrosion coating system, thereby avoiding defects such as pinholes and cracks in the coating caused by zinc powder agglomeration from the root. At the same time, the modifier forms a strong chemical bond with the hydroxyl groups on the surface of the zinc powder, which can strengthen the interfacial bonding force between the zinc powder and the resin matrix, greatly improve the adhesion and impact resistance of the coating, and lay a solid core foundation for the long-term protection of high solids anti-corrosion coatings.

[0015] (2) This application uses a combination of atomized coating and dry dispersion to prepare modified flake zinc powder. Compared with the traditional wet modification process, it does not rely on a large amount of diluent as a dispersion medium, which can reduce the generation and emission of organic waste from the source. At the same time, the modifier acts directly on the surface of the flake zinc powder in atomized form, which can achieve precise metering and targeted delivery of the modifier. While achieving a uniform and dense coating effect on the zinc powder surface, it reduces the waste of modifier from the source. There is no need for additional recycling or reuse of modifier, which simplifies the production process and further reduces material costs and environmental treatment pressure. During the dry dispersion process, the mechanical shear force of the glass beads can fully disperse the zinc powder agglomerates, and further enhance the uniformity of the coating layer, ensuring the batch consistency and stability of the modification effect, and completely avoiding the performance fluctuation problem caused by the recycling of diluent. In addition, the dry process significantly shortens the production cycle and reduces energy consumption, which is more suitable for the needs of large-scale industrial production.

[0016] (3) Glass beads are selected as grinding aids in this application. Compared with high-density, high-impact kinetic energy zirconium beads, the shear force of glass beads is more gentle. With an appropriate rotation speed of 40~120r / min, it can not only efficiently disperse zinc powder agglomerates, but also avoid the original particle size of the flaky zinc powder being excessively ground and refined. Thus, the physical shielding structure and sacrificial anode electrochemical protection performance given by the original particle size of the flaky zinc powder are completely preserved. This effectively avoids the risk of coating corrosion performance degradation caused by abnormal fluctuations in zinc powder particle size, and ensures the stability and reliability of the long-term protective performance of high solids anti-corrosion coatings.

[0017] The second objective of this application is achieved through the following technical solution: A modified flake zinc powder is provided, which is prepared by the modification method of the above-mentioned modified flake zinc powder.

[0018] The flaky zinc powder provided in this application has the following beneficial effects: The modified zinc powder provided in this application can precisely coat the surface of the flake zinc powder with characteristic functional groups of silane coupling agents, titanate coupling agents, or fluorocarbon surfactants according to the compatibility requirements of the target resin system. This effectively controls the surface polarity characteristics of the zinc powder, significantly improving its dispersion stability and interfacial compatibility in high-solids epoxy anti-corrosion coating systems. It fundamentally eliminates quality hazards such as pinholes and cracks in the coating caused by zinc powder agglomeration. At the same time, the modifier forms a strong chemical bond with the hydroxyl groups on the zinc powder surface, constructing a strong and tough interfacial bonding system between the zinc powder and the resin matrix. This greatly improves the adhesion and impact resistance of the coating, providing a solid core technical support for the long-term anti-corrosion performance of high-solids anti-corrosion coatings.

[0019] The third objective of this application is achieved through the following technical solution: An anti-corrosion coating is provided, comprising the following components by weight: 18-45 parts modified flake zinc powder, 30-65 parts pigments and fillers, 2-4 parts additives, 7-35 parts epoxy resin, 2-10 parts epoxy reactive diluent, 2-10 parts petroleum resin, 8-20 parts diluent and 5-20 parts modified amine curing agent; The modified flaky zinc powder is prepared by the modification method of the flaky zinc powder according to any one of claims 1 to 5, or is the modified flaky zinc powder according to claim 6.

[0020] In some embodiments, the pigments and fillers are selected from at least one of ultrafine barium sulfate, mica iron oxide powder, glass flakes, and mica powder.

[0021] In some embodiments, the epoxy resin is selected from at least one of E-20, E-44, and E-51; the petroleum resin is selected from at least one of C5 / C9 copolymer petroleum resin and C3 / 5 petroleum resin; and the epoxy reactive diluent is selected from at least one of allyl glycidyl ether and C12-C14 alkyl glycidyl ether.

[0022] The anti-corrosion coating provided in this application has the following beneficial effects: The anti-corrosion coating provided in this application, relying on the excellent dispersion stability and interfacial compatibility of modified flake zinc powder, can fully release the synergistic anti-corrosion performance of zinc powder's sacrificial anode protection and physical shielding while significantly reducing the amount of zinc powder used. This significantly extends the long-term protection period of the coating, making it particularly suitable for the protection needs of harsh corrosive environments such as marine engineering and heavy equipment. At the same time, the strong interfacial bonding force formed between the modified zinc powder and the resin matrix can simultaneously optimize the coating's adhesion, impact resistance, and resistance to media penetration. This fundamentally solves the problem of decreased mechanical properties of coatings that are easily caused by traditional high zinc powder addition, achieving a perfect balance and synergistic improvement in anti-corrosion performance and construction application performance.

[0023] The fourth objective of this application is achieved through the following technical solution: A method for preparing an anti-corrosion coating is provided, comprising the following steps: S1. Mix the modifier and dispersant according to the preset mass ratio, stir evenly, and then put them into a liquid storage device with pressure atomization function; S2. Add the preset mass of flake zinc powder to a conical double ribbon mixer and start stirring at a speed of 10~40 r / min. During stirring, spray the atomized modified dispersion liquid evenly onto the surface of the flake zinc powder through the atomizing nozzle at a pressure of 0.1~0.4 MPa. The atomization duration is 8~25 min. After atomization, continue stirring at a speed of 25 r / min for 10 min to obtain coated flake zinc powder. S3. The coated flaky zinc powder is transferred to a horizontal ball mill, and glass beads with a particle size of 3~10mm are used as grinding aids. The powder is dry dispersed at a speed of 40~120r / min for 1~3h. After sieving, the modified flaky zinc powder is obtained. S4. Add modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent to a disperser, and stir and disperse at a speed of 600~900r / min for 60~120min to obtain the main material of component A anti-corrosion coating. S5. The modified amine curing agent is packaged separately as component B curing agent. Before use, the two components are mixed evenly according to the mass ratio of A:B = (10~15):1.

[0024] The method for preparing an anti-corrosion coating provided in this application has the following beneficial effects: The method for preparing the anti-corrosion coating provided in this application can complete the modification process of the flake zinc powder by atomization during the stirring process. The overall preparation process is simple and efficient, without the need for complex special equipment and additional processes. It is suitable for large-scale continuous production needs, can effectively reduce production energy consumption and labor costs, and has significant advantages for industrial application. Detailed Implementation

[0025] In harsh corrosive environments such as marine engineering, heavy equipment, and bridge steel structures, long-lasting anti-corrosion coatings are core materials for ensuring the service life of infrastructure and industrial equipment. However, traditional anti-corrosion coating systems have long faced the dual contradiction between environmental protection requirements and anti-corrosion performance. On the one hand, global regulations on VOCs (volatile organic compounds) emission reduction continue to tighten – national standards such as GB / T 30981.2-2005 and GB / T 38597-2020 have successively tightened the VOCs limit for anti-corrosion coatings on metal substrates from 500g / L to 420g / L. T / CNCIA 01005-2018 further clarifies that high-solids epoxy coatings must meet the stringent requirements of VOCs < 250g / L and non-volatile matter volume fraction ≥ 70%. On the other hand, traditional zinc-rich coatings rely on the addition of high amounts of spherical zinc powder to achieve long-term corrosion protection, but high zinc powder content can easily lead to defects such as cracking of thick coatings and zinc powder agglomeration and sedimentation. Moreover, the VOCs emissions of solvent-based formulations far exceed the environmental protection red line, making it difficult to adapt to the current industry development needs of green corrosion protection.

[0026] Due to its unique flake-like structure, flake-shaped zinc powder has a higher specific surface area (0.01-0.06 m²) compared to spherical zinc powder. 2 / g) has a larger specific surface area (0.9-1.4m²). 2 / g), forming a layered physical shielding structure in the coating, can not only reduce the amount of zinc powder used by 2 / 3, but also achieve a long-lasting anti-corrosion effect without cracking in thick coatings, making it an ideal material to replace traditional spherical zinc powder. However, the high specific surface area of ​​flake zinc powder makes its surface highly polar, and it is very easy to agglomerate in high-solids epoxy systems, which seriously restricts its large-scale application in environmentally friendly anti-corrosion coatings. Patent CN202310982888.2 uses a wet process to modify flake zinc powder, which can achieve low VOCs and high anti-corrosion performance, but requires multiple processes such as grinding, filtering, drying, and crushing, which is complex, energy-intensive, and has low production efficiency. The dry modification technology of CN202510633116.7 is only suitable for water-based inorganic zinc silicate coating systems, which cannot meet the stringent requirements of epoxy coatings for interfacial compatibility and cannot meet the long-term protection requirements of high-solids epoxy anti-corrosion coatings.

[0027] Addressing the aforementioned industry pain points and technological gaps, this invention focuses on high-solids epoxy anti-corrosion coating systems. By precisely modifying the surface of flake zinc powder, it overcomes the technical challenges of poor dispersion stability and insufficient interfacial compatibility of flake zinc powder in high-solids epoxy systems, thus constructing a new generation of anti-corrosion coating technology system that combines long-lasting anti-corrosion, low VOC emissions, and excellent construction performance.

[0028] In one typical embodiment of this application, a method for modifying flake zinc powder is provided, comprising the following steps: The flaky zinc powder was stirred at a speed of 10~40 r / min. During the stirring process, the modified dispersion was sprayed onto it. After atomization, the flaky zinc powder was transferred to a horizontal ball mill and dispersed for 1~3 hours at a speed of 40~120 r / min using glass beads as a grinding aid. After sieving, the modified flaky zinc powder was obtained. The modified dispersion includes a dispersant and a modifier, wherein the modifier is selected from at least one of silane coupling agents, titanate coupling agents, and fluorocarbon surfactants.

[0029] Specifically, stirring the flake zinc powder at a speed of 10-40 r / min involves placing the powder in commonly used industrial dispersion equipment, such as a high-speed disperser, a conical double-ribbon mixer, or a plow-type mixer. Stirring keeps the zinc powder in a dynamic tumbling state, ensuring sufficient contact with the atomized modified dispersion. Controlling the stirring speed within the 10-40 r / min range allows for a precise match between the zinc powder tumbling rate and the modifier contact efficiency. If the speed is below 10 r / min, the zinc powder flow rate is too slow, failing to form a uniform dynamic tumbling field. Some zinc powder remains stationary for extended periods, leading to uneven contact between the atomized modifier and the zinc powder, and even modifier flow and aggregation. If the speed is above 40 r / min, the mechanical shear force generated by stirring is excessive, dramatically increasing the impact kinetic energy between zinc powder particles. This can damage the original flaky structure of the zinc powder, causing unnecessary refinement and weakening its physical shielding effect.

[0030] The modified dispersion can be atomized and sprayed using pneumatic nozzles or pressure atomizing nozzles to ensure that the modifier uniformly covers the zinc powder surface with droplet sizes of 5-20 μm. After atomization, the pre-treated zinc powder is transferred to a horizontal ball mill. Through the mechanical shearing and grinding action of glass beads, the uniformity and bonding strength of the modifier on the zinc powder surface are further enhanced, while breaking up zinc powder agglomerates. Compared with high-density zirconium beads, glass beads have a gentler shearing force. With an appropriate rotation speed of 40-120 r / min, they can efficiently disperse zinc powder agglomerates while avoiding excessive grinding and refinement of the original zinc powder particle size. This preserves the flaky structure of the zinc powder and the sacrificial anode electrochemical protection performance, effectively avoiding the risk of coating corrosion resistance degradation caused by abnormal fluctuations in zinc powder particle size.

[0031] The ball milling speed is designed to be between 40 and 120 r / min. If the speed is below 40 r / min, the kinetic energy of the glass beads is insufficient to effectively disperse the zinc powder agglomerates, making it difficult to ensure the uniform distribution of the modifier on the zinc powder surface. If the speed is above 120 r / min, the impact kinetic energy of the glass beads is too high, which will cause the flaky zinc powder to break and deform, destroying its scaly structure and thus weakening the physical shielding and electrochemical protection performance of the coating. Through dry ball milling dispersion for 1 to 3 hours, a firm bond and uniform coating of the modifier on the zinc powder surface can be achieved, ultimately producing modified flaky zinc powder with excellent dispersibility and stable performance.

[0032] As a preferred embodiment, the modifier can be at least one of silane coupling agents, titanate coupling agents, and fluorocarbon surfactants. For example, silane coupling agents can be used alone, or a mixture of silane coupling agents and titanate coupling agents can be used, or a mixture of silane coupling agents, titanate coupling agents, and fluorocarbon surfactants can be used. These modifiers can reduce the surface polarity of flake zinc powder and improve its compatibility with organic resins through different mechanisms of action, thus adapting to different corrosion protection scenarios.

[0033] The core innovation of this application lies in the first-ever precise coupling of the stirring flow field and the atomization field. By stirring at a low speed of 10~40 r / min, the flake zinc powder is formed into a tumbling fluidized bed, ensuring that the flake zinc powder can be periodically exposed to the atomization area. At the same time, the modified dispersion is sprayed at a pressure of 0.1~0.4 MPa to form micron-sized droplets of 5~20 μm. The droplets uniformly impact the zinc powder surface in the stirring flow field, realizing point-to-point bonding between the modifier molecular chain and the hydroxyl groups on the zinc powder surface, avoiding the problems of modifier agglomeration or local over-addition in traditional processes.

[0034] Compared with traditional wet processes, this application reduces the amount of modifier used from 10%~20% of the zinc powder weight to 0.5%~4% through a stirring-and-atomizing process, reduces diluent consumption by more than 90%, and increases the effective utilization rate of the modifier from 25% to over 90%, eliminating modifier waste and organic waste emissions at the source. The oil absorption value of the modified flake zinc powder is reduced from 22g / 100g to 12.9~16.2g / 100g, and the dispersion stability in high-solids epoxy coatings is improved by 60%. The VOCs emission of the prepared anti-corrosion coating is as low as 170g / L, far below the national standard limit of 250g / L. The neutral salt spray protection time of the coating is extended from less than 1000h to 1324h~3500h, and the adhesion is improved from 3.7MPa to 8.1~13.2MPa, achieving a dual breakthrough in environmental protection and anti-corrosion performance.

[0035] Furthermore, the amount of the modified dispersion is 0.5% to 4% of the weight of the flake zinc powder, and the mass ratio of the dispersant to the modifier is 1:(1 to 3).

[0036] Specifically, the amount of modified dispersion is controlled at 0.5%~4% of the zinc powder weight, based on precise calculations of the specific surface area, surface hydroxyl density, and modifier molecular size of the flake zinc powder: for small-particle-size zinc powder with a D50 of 5~10μm (specific surface area 1.2~1.4m²), the modified dispersion is used at this amount. 2 The modified dispersion dosage is preferably 2.5%~4% to ensure that the modifier fully covers the surface of the zinc powder with a high specific surface area; for large-particle-size zinc powder with a D50 of 20~45μm (specific surface area 0.9~1.1m²), the dosage is also suitable. 2 The modified dispersion dosage can be as low as 0.5% to 2% to achieve complete passivation of surface active sites. If the dosage is less than 0.5%, the modifier molecules cannot completely cover the active hydroxyl groups on the zinc powder surface, resulting in uneven polarity of the zinc powder surface, which is still prone to agglomeration in high solids systems. If the dosage is higher than 4%, the excessive modifier will form multiple physical adsorption layers on the zinc powder surface, which not only wastes the modifier and increases costs, but also causes it to fall off during subsequent ball milling or coating preparation due to weak interlayer bonding, which in turn triggers secondary agglomeration of zinc powder and destroys the uniformity of the coating.

[0037] Setting the mass ratio of dispersant to modifier to 1:(1~3) aims to maximize the synergistic effect of the steric hindrance of the dispersant and the interfacial bonding of the modifier. The main function of the dispersant is to reduce the surface tension of the modifier solution, promote the wetting and spreading of the modifier on the zinc powder surface, and simultaneously form a steric hindrance layer to prevent zinc powder agglomeration by binding with the hydroxyl groups on the zinc powder surface through its anchoring groups. The modifier, on the other hand, binds with the hydroxyl groups on the zinc powder surface through chemical bonds such as silicon-oxygen bonds and titanium-oxygen bonds, endowing the zinc powder with new surface properties. When the ratio is 1:1, the dispersant and modifier molecules form an alternating adsorption layer on the zinc powder surface, ensuring both effective bonding of the modifier and maintaining the dispersion stability of the zinc powder through the steric hindrance of the dispersant. When the ratio is 1:3, the modifier molecules dominate, forming a thicker functionalized layer on the zinc powder surface and enhancing the interfacial compatibility with the resin matrix. If the dispersant ratio is too high (>1:1), excessive dispersant molecules will occupy the active sites on the zinc powder surface, inhibiting the chemical bonding of the modifier and weakening the interfacial bonding between the zinc powder and the resin. If the modifier ratio is too high (>1:3), the dispersant is insufficient to completely encapsulate the modifier molecules, causing the modifier to agglomerate and fail to spread evenly on the zinc powder surface, thus reducing the dispersibility of the zinc powder. Setting this ratio range ensures that the modifier forms a uniform and firm functionalized layer on the zinc powder surface, while maintaining the long-term dispersion stability of the zinc powder in the coating system.

[0038] It is understandable that when using the modification method of this application to coat and modify flake zinc powder, even if the amount of modified dispersion is strictly controlled within the range of 0.5% to 4% of the zinc powder weight, it is not necessary to pursue 100% full coverage of the zinc powder surface. This is a key design of this application based on the core innovative thinking of precise modification and efficient utilization. If the amount of modifier is blindly increased in order to achieve complete coating, a large number of modifier molecules will form a free state because they cannot bind to the active sites on the zinc powder surface, which not only causes ineffective waste of modifier but also significantly increases production costs. The modification strategy of this application focuses on the targeted modification of the active sites on the zinc powder surface. Only coating the zinc powder surface is needed to effectively reduce the surface polarity of the zinc powder and improve its dispersion stability in high-solids epoxy systems. The optimal modification effect is achieved with the minimum amount of modifier, while retaining some of the original characteristics of the zinc powder surface and maintaining the maximum performance of its sacrificial anode electrochemical protection efficiency.

[0039] Furthermore, the step of stirring the flake zinc powder at a speed of 10~40 r / min, and spraying the atomized modified dispersion onto it during the stirring process, specifically includes: Add the flake zinc powder to the conical double ribbon mixer and stir at a speed of 10~40 r / min. During the stirring process, spray the modified dispersion liquid into the flake zinc powder through the atomizing nozzle of the conical double ribbon mixer at a pressure of 0.1~0.4 MPa for 8~25 min. Then continue stirring at a speed of 25 r / min for 10 minutes.

[0040] Furthermore, the D50 particle size of the flaky zinc powder is 5~45μm, and the zinc content is >88%; the particle size of the glass beads is 3~10mm, and the mass ratio of glass beads to flaky zinc powder is (4~10):1.

[0041] Furthermore, the modified dispersion also includes a diluent, the amount of which is 10% to 30% of the total weight of the modified dispersion.

[0042] It is understandable that the selection, addition method, and dosage of dispersants and diluents are conventional techniques that those skilled in the art can master.

[0043] In some embodiments described above, methods for modifying flake zinc powder were proposed. However, simply describing the modification process is insufficient to directly demonstrate the unique properties and application advantages of the prepared modified flake zinc powder, which may lead to insufficient understanding of its value in specific application scenarios. Therefore, this application proposes a modified flake zinc powder prepared using the aforementioned methods. The modified flake zinc powder prepared by the above methods significantly improves its dispersibility and stability in organic systems and enhances the interfacial bonding between the flake zinc powder and the coating matrix, thereby improving the density and adhesion of the coating film. Therefore, when this modified flake zinc powder is applied to anti-corrosion coatings, it can form a more continuous, dense, and uniform anti-corrosion layer, effectively improving the long-term anti-corrosion performance and mechanical properties of the coating and extending the service life of the coated material.

[0044] This application also discloses an anti-corrosion coating, comprising the following components by weight: 18-45 parts modified flake zinc powder, 30-65 parts pigments and fillers, 2-4 parts additives, 7-35 parts epoxy resin, 2-10 parts epoxy reactive diluent, 2-10 parts petroleum resin, 8-20 parts diluent and 5-20 parts modified amine curing agent; The modified flaky zinc powder is prepared by the modification method of the above-mentioned flaky zinc powder, or is the above-mentioned modified flaky zinc powder.

[0045] Furthermore, the pigments and fillers are selected from at least one of ultrafine barium sulfate, mica iron oxide powder, glass flakes, and mica powder.

[0046] Further, the epoxy resin is selected from at least one of E-20, E-44 and E-51; the petroleum resin is selected from at least one of C5 / C9 copolymer petroleum resin and C3 / 5 petroleum resin; and the epoxy reactive diluent is selected from at least one of allyl glycidyl ether and C12-C14 alkyl glycidyl ether.

[0047] This application also discloses a method for preparing an anti-corrosion coating, comprising the following steps: S1. Mix the modifier and dispersant according to the preset mass ratio, stir evenly, and then put them into a liquid storage device with pressure atomization function; S2. Add the preset mass of flake zinc powder to a conical double-ribbon mixer and start stirring at a speed of 10~40 r / min. During stirring, spray the atomized modified dispersion liquid evenly onto the surface of the flake zinc powder through the atomizing nozzle at a pressure of 0.1~0.4 MPa. The atomization duration is 8~25 min. After atomization, continue stirring at a speed of 25 r / min for 10 min to obtain modified flake zinc powder. S3. The modified flaky zinc powder is transferred to a horizontal ball mill, and glass beads with a particle size of 3~10mm are used as grinding aids. The powder is dry-dispersed and ground at a speed of 40~120r / min for 1~3h. After sieving, the modified flaky zinc powder is obtained. S4. Add modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, and stir and disperse at a speed of 600~900r / min for 60~120min to obtain component A anti-corrosion coating. S5. The modified amine curing agent is packaged separately as component B curing agent. Before use, the two components are mixed evenly according to the mass ratio of A:B = (10~15):1.

[0048] The beneficial effects of this application will be further illustrated below with reference to the embodiments.

[0049] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. All components described in this application are commercially available. The components described in the specific implementation or embodiments are mass ratios or mass parts.

[0050] The embodiments of this invention can be tested using the following testing methods for the corresponding items: 1. D50 (median particle size): Determined using a laser particle size analyzer according to GB / T 19077.1-2016 "Particle size analysis by laser diffraction - Part 1: General rules"; 2. Zinc content: determined according to the chemical analysis method (EDTA complexometric titration) in HG / T 3668-2020 "Zinc-Rich Coatings"; 3. Oil absorption value: determined according to GB / T 1712-1989 "Determination of Oil Absorption of Pigments"; 4. VOCs emissions: In accordance with GB / T 38597-2020 "Technical Requirements for Coatings with Low Volatile Organic Compound Content", the emissions were determined by gas chromatography. 5. Adhesion: The adhesion was determined according to GB / T 5210-2006 "Paints and Varnishes - Pull-off Test", and the results are expressed in MPa. 6. Neutral salt spray: The test was conducted in accordance with GB / T 1771-2007 "Determination of resistance to neutral salt spray of paints and varnishes". The test conditions were 5% NaCl solution, pH value 6.5-7.2, and continuous spraying at 35℃.

[0051] Example 1 1. Preparation of modified flake zinc powder: 1.1 Preparation of composite modifier: γ-glycidyl etheroxypropyltrimethoxysilane (KH-560) and dispersant 6208 were mixed evenly at a mass ratio of 1:1 to obtain a modified dispersion; 1.2 Atomization Coating Pretreatment: 98.6 parts by weight of flake zinc powder (D50=22.8μm, zinc content 93%) was added to a conical double-ribbon mixer. The mixer was turned on and the speed was adjusted to 40 r / min. Then, 1.4 parts by weight of the modified dispersion was injected into a storage tank with pressure atomization function. The mixture was then uniformly sprayed onto the surface of the agitated zinc powder through an ultra-fine atomizing nozzle at the top of the mixer at an atomization pressure of 0.15 MPa within 8 minutes. After atomization, the mixture was stirred for another 10 minutes at a speed of 25 r / min to ensure that the modifier was fully spread and adsorbed on the surface of the zinc powder, thus obtaining the pretreated coated zinc powder. 1.3 Dry ball milling dispersion: The pretreated coated zinc powder was transferred to a horizontal ball mill. Glass beads with a particle size of 5 mm were selected as the grinding medium. The ball-to-powder ratio of glass beads to coated zinc powder was 5:1. The speed of the ball mill was adjusted to 80 r / min, and dry dispersion was carried out for 2 hours. After ball milling, the powder was sieved to obtain the modified flaky zinc powder product. 1.4 The D50, metallic zinc content and oil absorption of the flake zinc powder were tested. The test results are shown in Table 14.

[0052] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 1: Table 1: Raw Material Formulation Table for Example 1

[0053] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, petroleum resin and diluent into a disperser, and stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE 3117 curing agent and polyamide 640 curing agent evenly and encapsulate them as the B component curing agent.

[0054] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 92.86:7.14, and then applied. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0055] Example 2 1. Preparation of modified flake zinc powder: 1.1 Preparation of composite modifier: γ-glycidyl etheroxypropyltrimethoxysilane (KH-560) and dispersant 6208 were mixed evenly at a mass ratio of 1:1 to obtain a modified dispersion; 1.2 Atomization Coating Pretreatment: 97.5 parts by weight of flake zinc powder (D50=22.8μm, zinc content 93%) were added to a conical double-ribbon mixer. The mixer was turned on and the speed was adjusted to 40 r / min. Then, 2.5 parts by weight of the modified dispersion was injected into a storage tank with pressure atomization function. The mixture was then uniformly sprayed onto the surface of the agitated zinc powder through the ultra-fine atomizing nozzle at the top of the mixer at an atomization pressure of 0.15 MPa within 15 minutes. After atomization, the mixture was stirred for another 10 minutes at a speed of 25 r / min to ensure that the modifier was fully spread and adsorbed on the surface of the zinc powder, thus obtaining the pretreated coated zinc powder. 1.3 Dry ball milling dispersion: The pretreated coated zinc powder was transferred to a horizontal ball mill. Glass beads with a particle size of 5 mm were selected as the grinding medium. The ball-to-powder ratio of glass beads to coated zinc powder was 5:1. The speed of the ball mill was adjusted to 80 r / min, and dry dispersion was carried out for 2 hours. After ball milling, the powder was sieved to obtain the modified flaky zinc powder product. 1.4 The D50, metallic zinc content and oil absorption of the flake zinc powder were tested. The test results are shown in Table 14.

[0056] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 2: Table 2: Raw Material Formulation Table for Example 2

[0057] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, and stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE 3117 curing agent and polyamide 640 curing agent evenly and encapsulate them as the B component curing agent.

[0058] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 92.1:7.9, and then coated. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0059] Example 3 1. Preparation of modified flake zinc powder: 1.1 Preparation of composite modifier: γ-glycidyl etheroxypropyltrimethoxysilane (KH-560) and dispersant 6208 were mixed evenly at a mass ratio of 1:1 to obtain a modified dispersion; 1.2 Atomization Coating Pretreatment: 96.5 parts by weight of flake zinc powder (D50=22.8μm, zinc content 93%) were added to a conical double-ribbon mixer. The mixer was turned on and the speed was adjusted to 40 r / min. Then, 3.5 parts by weight of the modified dispersion was injected into a storage tank with pressure atomization function. The mixture was then sprayed evenly onto the surface of the agitated zinc powder through an ultra-fine atomizing nozzle at the top of the mixer at an atomization pressure of 0.15 MPa within 15 minutes. After atomization, the mixture was stirred for another 10 minutes at a speed of 25 r / min to ensure that the modifier was fully spread and adsorbed on the surface of the zinc powder, thus obtaining the pretreated coated zinc powder. 1.3 Dry ball milling dispersion: The pretreated coated zinc powder was transferred to a horizontal ball mill. Glass beads with a particle size of 5 mm were selected as the grinding medium. The ball-to-powder ratio of glass beads to coated zinc powder was 5:1. The speed of the ball mill was adjusted to 80 r / min, and dry dispersion was carried out for 2 hours. After ball milling, the powder was sieved to obtain the modified flaky zinc powder product. 1.4 The D50, metallic zinc content and oil absorption of the flake zinc powder were tested. The test results are shown in Table 14.

[0060] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 3: Table 3: Raw Material Formulation Table for Example 3

[0061] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, and stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE 3117 curing agent and polyamide 640 curing agent evenly and encapsulate them as the B component curing agent.

[0062] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 91.87:8.13, and then applied. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0063] Example 4 1. Preparation of modified flake zinc powder: 1.1 Preparation of composite modifier: γ-glycidyl etheroxypropyltrimethoxysilane (KH-560) and dispersant 6208 were mixed evenly at a mass ratio of 1:1 to obtain a modified dispersion; 1.2 Atomization Coating Pretreatment: 96 parts by weight of flake zinc powder (D50=22.8μm, zinc content 93%) were added to a conical double-ribbon mixer. The mixer was turned on and the speed was adjusted to 40 r / min. Then, 4 parts by weight of the modified dispersion was injected into a storage tank with pressure atomization function. The mixture was then sprayed evenly onto the surface of the agitated zinc powder through an ultra-fine atomizing nozzle at the top of the mixer at an atomization pressure of 0.15 MPa within 15 minutes. After atomization, the mixture was stirred for another 10 minutes at a speed of 25 r / min to ensure that the modifier was fully spread and adsorbed on the surface of the zinc powder, thus obtaining the pretreated coated zinc powder. 1.3 Dry ball milling dispersion: The pretreated coated zinc powder was transferred to a horizontal ball mill. Glass beads with a particle size of 5 mm were selected as the grinding medium. The ball-to-powder ratio of glass beads to coated zinc powder was 5:1. The speed of the ball mill was adjusted to 80 r / min, and dry dispersion was carried out for 2 hours. After ball milling, the powder was sieved to obtain the modified flaky zinc powder product. 1.4 The D50, metallic zinc content and oil absorption of the flake zinc powder were tested. The test results are shown in Table 14.

[0064] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 4: Table 4: Raw Material Formulation Table for Example 4

[0065] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, and stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE 3117 curing agent and polyamide 640 curing agent evenly and encapsulate them as the B component curing agent.

[0066] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 91.87:8.13, and then applied. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0067] Example 5 1. Preparation of modified flake zinc powder: 1.1 Preparation of composite modifier: γ-aminopropyltriethoxysilane (KH-550) and dispersant 6208 were mixed evenly at a mass ratio of 1:1 to obtain a modified dispersion; 1.2 Atomization Coating Pretreatment: Add 98.3 parts by weight of flake zinc powder (D50=8.5μm, zinc content 88.5%) to a conical double-ribbon mixer, start stirring and adjust the speed to 40 r / min; then inject 1.7 parts by weight of modified dispersion into a storage tank with pressure atomization function, and spray it evenly onto the surface of the churning zinc powder through the ultra-fine atomizing nozzle at the top of the mixer at an atomization pressure of 0.1MPa within 10 minutes; after atomization, continue stirring at 25 r / min for 10 minutes to ensure that the modifier is fully spread and adsorbed on the surface of the zinc powder, thus obtaining the pretreated coated zinc powder; 1.3 Dry ball milling dispersion: The pretreated coated zinc powder was transferred to a horizontal ball mill. Glass beads with a particle size of 5 mm were selected as the grinding medium. The ball-to-powder ratio of glass beads to coated zinc powder was 5:1. The speed of the ball mill was adjusted to 80 r / min, and dry dispersion was carried out for 2 hours. After ball milling, the powder was sieved to obtain the modified flaky zinc powder product. 1.4 The D50, metallic zinc content and oil absorption of the flake zinc powder were tested. The test results are shown in Table 14.

[0068] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 5: Table 5: Raw Material Formulation Table for Example 5

[0069] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, and stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE 3117 curing agent and polyamide 640 curing agent evenly and encapsulate them as the B component curing agent.

[0070] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 92.1:7.9, and then coated. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0071] Example 6 1. Preparation of modified flake zinc powder: 1.1 Preparation of composite modifier: 2,4,6-tris(dimethylaminomethyl)phenol and dispersant BYK-164 were mixed evenly at a mass ratio of 1:1 to obtain a modified dispersion; 1.2 Atomization Coating Pretreatment: 98 parts by weight of flake zinc powder (D50=24.4μm, zinc content 93.3%) were added to a conical double-ribbon mixer. The mixer was turned on and the speed was adjusted to 40 r / min. Then, 2 parts by weight of the modified dispersion was injected into a storage tank with pressure atomization function. The mixture was then sprayed evenly onto the surface of the agitated zinc powder through an ultra-fine atomizing nozzle at the top of the mixer at an atomization pressure of 0.15 MPa within 10 minutes. After atomization, the mixture was stirred for another 10 minutes at a speed of 25 r / min to ensure that the modifier was fully spread and adsorbed on the surface of the zinc powder, thus obtaining the pretreated coated zinc powder. 1.3 Dry ball milling dispersion: The pretreated coated zinc powder was transferred to a horizontal ball mill. Glass beads with a particle size of 5 mm were selected as the grinding medium. The ball-to-powder ratio of glass beads to coated zinc powder was 5:1. The speed of the ball mill was adjusted to 60 r / min, and dry dispersion was carried out for 2 hours. After ball milling, the powder was sieved to obtain the modified flaky zinc powder product. 1.4 The D50, metallic zinc content and oil absorption of the flake zinc powder were tested. The test results are shown in Table 14.

[0072] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 6: Table 6: Raw Material Formulation Table for Example 6

[0073] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, and stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE3060 curing agent and polyamide 650 curing agent evenly and package them as the B component curing agent.

[0074] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 93.31:6.69, and then coated. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0075] Example 7 1. Preparation of modified flake zinc powder: 1.1 Preparation of composite modifier: Fluorocarbon surfactant FS-3100 and dispersant BYK-110 were mixed evenly at a mass ratio of 1:1 to obtain a modified dispersion; 1.2 Atomization Coating Pretreatment: 98.5 parts by weight of flake zinc powder (D50=16.2μm, zinc content 92.5%) was added to a conical double-ribbon mixer. The mixer was turned on and the speed was adjusted to 40 r / min. Then, 1.5 parts by weight of the modified dispersion was injected into a storage tank with pressure atomization function. The mixture was then sprayed evenly onto the surface of the agitated zinc powder through an ultra-fine atomizing nozzle at the top of the mixer at an atomization pressure of 0.15 MPa within 10 minutes. After atomization, the mixture was stirred for another 10 minutes at a speed of 25 r / min to ensure that the modifier was fully spread and adsorbed on the surface of the zinc powder, thus obtaining the pretreated coated zinc powder. 1.3 Dry ball milling dispersion: The pretreated coated zinc powder was transferred to a horizontal ball mill. Glass beads with a particle size of 5 mm were selected as the grinding medium. The ball-to-powder ratio of glass beads to coated zinc powder was 5:1. The speed of the ball mill was adjusted to 80 r / min, and dry dispersion was carried out for 2 hours. After ball milling, the powder was sieved to obtain the modified flaky zinc powder product. 1.4 The D50, metallic zinc content and oil absorption of the flake zinc powder were tested. The test results are shown in Table 14.

[0076] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 7: Table 7: Raw Material Formulation Table for Example 7

[0077] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, and stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE3060 curing agent and polyamide 650 curing agent evenly and package them as the B component curing agent.

[0078] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 90.76:9.24, and then applied. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0079] Example 8 1. Preparation of modified flake zinc powder: 1.1 Preparation of composite modifier: Nonionic fluorocarbon surfactant FS-3100 and dispersant BYK-110 were mixed evenly at a mass ratio of 1:1 to obtain a modified dispersion; 1.2 Atomization Coating Pretreatment: 97.5 parts by weight of flake zinc powder (D50=16.2μm, zinc content 92.5%) was added to a conical double-ribbon mixer. The mixer was turned on and the speed was adjusted to 40 r / min. Then, 2.5 parts by weight of the modified dispersion was injected into a storage tank with pressure atomization function. The mixture was then sprayed evenly onto the surface of the agitated zinc powder through an ultra-fine atomizing nozzle at the top of the mixer at an atomization pressure of 0.15 MPa within 10 minutes. After atomization, the mixture was stirred for another 10 minutes at a speed of 25 r / min to ensure that the modifier was fully spread and adsorbed on the surface of the zinc powder, thus obtaining the pretreated coated zinc powder. 1.3 Dry ball milling dispersion: The pretreated coated zinc powder was transferred to a horizontal ball mill. Glass beads with a particle size of 5 mm were selected as the grinding medium. The ball-to-powder ratio of glass beads to coated zinc powder was 5:1. The speed of the ball mill was adjusted to 80 r / min, and dry dispersion was carried out for 2 hours. After ball milling, the powder was sieved to obtain the modified flaky zinc powder product. 1.4 The D50, metallic zinc content and oil absorption of the flake zinc powder were tested. The test results are shown in Table 14.

[0080] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 8: Table 8: Raw Material Formulation Table for Example 8

[0081] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, and stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE3060 curing agent and polyamide 650 curing agent evenly and package them as the B component curing agent.

[0082] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 90.37:9.63, and then applied. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0083] Example 9 1. Preparation of modified flake zinc powder: 1.1 Preparation of composite modifier: KH-560, FS-3100 and dispersant Tech 6208 were mixed evenly at a mass ratio of 1:0.5:1 to obtain a modified dispersion; 1.2 Atomization Coating Pretreatment: 98.5 parts by weight of flake zinc powder (D50=16.1μm, zinc content 92.5%) was added to a conical double-ribbon mixer. The mixer was turned on and the speed was adjusted to 40 r / min. Then, 1.5 parts by weight of the modified dispersion was injected into a storage tank with pressure atomization function. The mixture was then sprayed evenly onto the surface of the agitated zinc powder through an ultra-fine atomizing nozzle at the top of the mixer at an atomization pressure of 0.15 MPa within 10 minutes. After atomization, the mixture was stirred for another 10 minutes at a speed of 25 r / min to ensure that the modifier was fully spread and adsorbed on the surface of the zinc powder, thus obtaining the pretreated coated zinc powder. 1.3 Dry ball milling dispersion: The pretreated coated zinc powder was transferred to a horizontal ball mill. Glass beads with a particle size of 5 mm were selected as the grinding medium. The ball-to-powder ratio of glass beads to coated zinc powder was 5:1. The speed of the ball mill was adjusted to 80 r / min, and dry dispersion was carried out for 2 hours. After ball milling, the powder was sieved to obtain the modified flaky zinc powder product. 1.4 The D50, metallic zinc content and oil absorption of the flake zinc powder were tested. The test results are shown in Table 14.

[0084] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 9: Table 9: Raw Material Formulation Table for Example 9

[0085] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE 3060 curing agent and polyamide 650 curing agent evenly and package them as the B component curing agent.

[0086] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 90.37:9.63, and then applied. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0087] Example 10 1. Preparation of modified flake zinc powder: 1.1 Preparation of composite modifier: Isopropyl triisostearate titanate KR-TTS, dispersant 6208 and propylene glycol methyl ether acetate were mixed evenly in a mass ratio of 1:1:1 to prepare a modified dispersion. 1.2 Atomization Coating Pretreatment: 97.5 parts by weight of flake zinc powder (D50=21.5μm, zinc content 93%) was added to a conical double-ribbon mixer. The mixer was turned on and the speed was adjusted to 40 r / min. Then, 2.5 parts by weight of the modified dispersion was injected into a storage tank with pressure atomization function. The mixture was then sprayed evenly onto the surface of the agitated zinc powder through an ultra-fine atomizing nozzle at the top of the mixer at an atomization pressure of 0.15 MPa within 8 minutes. After atomization, the mixture was stirred for another 10 minutes at a speed of 25 r / min to ensure that the modifier was fully spread and adsorbed on the surface of the zinc powder, thus obtaining the pretreated coated zinc powder. 1.3 Dry ball milling dispersion: The pretreated coated zinc powder was transferred to a horizontal ball mill. Glass beads with a particle size of 5 mm were selected as the grinding medium. The ball-to-powder ratio of glass beads to coated zinc powder was 5:1. The speed of the ball mill was adjusted to 80 r / min, and dry dispersion was carried out for 2 hours. After ball milling, the powder was sieved to obtain the modified flaky zinc powder product. 1.4 The D50, metallic zinc content and oil absorption of the flake zinc powder were tested. The test results are shown in Table 14.

[0088] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 10: Table 10: Raw Material Formulation Table for Example 10

[0089] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE 3060 curing agent and polyamide 650 curing agent evenly and package them as the B component curing agent.

[0090] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 91.46:8.54, and then coated. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0091] Example 11 1. Preparation of modified flake zinc powder: 1.1 Preparation of composite modifier: KH-560, KR-TTS and dispersant 6208 were mixed evenly at a mass ratio of 0.8:0.7:1.5 to prepare a modified dispersion; 1.2 Atomization Coating Pretreatment: 98.5 parts by weight of flake zinc powder (D50=21.5μm, zinc content 93%) was added to a conical double-ribbon mixer. The mixer was turned on and the speed was adjusted to 40 r / min. Then, 1.5 parts by weight of the modified dispersion was injected into a storage tank with pressure atomization function. The mixture was then sprayed evenly onto the surface of the agitated zinc powder through an ultra-fine atomizing nozzle at the top of the mixer at an atomization pressure of 0.15 MPa within 8 minutes. After atomization, the mixture was stirred for another 10 minutes at a speed of 25 r / min to ensure that the modifier was fully spread and adsorbed on the surface of the zinc powder, thus obtaining the pretreated coated zinc powder. 1.3 Dry ball milling dispersion: The pretreated coated zinc powder was transferred to a horizontal ball mill. Glass beads with a particle size of 5 mm were selected as the grinding medium. The ball-to-powder ratio of glass beads to coated zinc powder was 5:1. The speed of the ball mill was adjusted to 80 r / min, and dry dispersion was carried out for 2 hours. After ball milling, the powder was sieved to obtain the modified flaky zinc powder product. 1.4 The D50, metallic zinc content and oil absorption of the flake zinc powder were tested. The test results are shown in Table 14.

[0092] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 11: Table 11: Raw material formula for Example 11:

[0093] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE 3060 curing agent and polyamide 650 curing agent evenly and package them as the B component curing agent.

[0094] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 90.37:9.63, and then applied. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0095] Comparative Example 1 1. The difference between Comparative Example 1 and Example 1 is that the flake zinc powder was not modified, and the D50 of the flake zinc powder was 21.5 μm, and the zinc content was 93%.

[0096] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 12: Table 12: Raw material formula for Comparative Example 1:

[0097] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE 3060 curing agent and polyamide 650 curing agent evenly and package them as the B component curing agent.

[0098] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 93.31:6.69, and then applied. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0099] Comparative Example 2 1. The difference between Comparative Example 2 and Example 1 is that the flake zinc powder was not modified, and the D50 of the flake zinc powder was 8.5 μm, and the zinc content was 88.5%.

[0100] 2. Preparation of anti-corrosion coatings: 2.1 The raw material formula is shown in Table 13: Table 13: Raw material formula for Comparative Example 2:

[0101] 2.2 Preparation of anti-corrosion coating: Weigh the raw materials according to the required amount, add the modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent into a disperser, stir and disperse at a speed of 600 r / min for 120 min to obtain the A component anti-corrosion coating main material; mix LITE 3060 curing agent and polyamide 650 curing agent evenly and package them as the B component curing agent.

[0102] 2.3 Product testing: The A component anti-corrosion coating material and the B component curing agent were mixed evenly at a mass ratio of 92.26:7.74, and then applied. The VOC emission, adhesion and neutral salt spray tests were conducted according to the above method. The test results are shown in Table 14.

[0103] Table 14: Test Results of Each Example and Comparative Example

[0104] As can be seen from the above embodiments and comparative examples, Comparative Example 1 uses unmodified conventional particle size flake zinc powder, and Comparative Example 2 uses unmodified small particle size flake zinc powder. Both have the problems of high oil absorption value and poor dispersibility, resulting in the VOCs emission of the prepared coating reaching 350g / L, far exceeding the environmental protection standard of 250g / L. Among them, the small particle size zinc powder of Comparative Example 2, because it is unmodified, has a coating adhesion of only 3.7MPa and a neutral salt spray resistance of only 600h, which cannot meet the requirements for long-term corrosion protection.

[0105] All embodiments employed a composite modification process combining atomized coating pretreatment and dry ball milling dispersion. After modification, the oil absorption value of the zinc powder decreased from 22.1-23.2 g / 100g to 12.9-16.2 g / 100g, significantly improving dispersibility. The VOC emissions of the coatings prepared in each embodiment were controlled within 170-245 g / L, fully meeting the environmental standard of ≤250 g / L. Coating adhesion was generally improved to 8.1-13.2 MPa, and the neutral salt spray duration reached over 1324 hours, achieving the dual goals of low VOC emissions and long-lasting corrosion protection.

[0106] More specifically, different types of modifiers have varying effects on regulating the surface polarity of zinc powder, directly impacting coating performance. Examples 1-4 used KH-560 silane coupling agent, suitable for zinc powders of conventional particle sizes. With increasing modifier dosage, the neutral salt spray performance of the coating increased from 1424h to 3200h, while VOCs remained stable at 221-245g / L. Example 5 used KH-550 silane coupling agent, specifically designed for modifying small-particle-size zinc powder, solving the agglomeration problem and ensuring the coating performance met standards. Examples 8-9 used FS-3100 fluorocarbon surfactant, significantly reducing coating VOCs to 170-176g / L, representing the lowest VOC emissions among all examples and suitable for scenarios with extremely high environmental requirements. Example 10 uses KR-TTS titanate coupling agent, which significantly enhances the interfacial bonding between zinc powder and resin, achieving a coating adhesion of 10.9 MPa while maintaining long-term anti-corrosion performance for 3200 hours, making it suitable for applications with high mechanical performance requirements. Example 9 uses a composite modification of KH-560, FS-3100, and a dispersant, while Example 11 uses a composite modification of KH-560, KR-TTS, and a dispersant. Through the synergistic effect of different modifiers, a comprehensive performance improvement is achieved. Among them, Example 11 achieves a neutral salt spray time of 3500 hours, which is the best performance among all examples.

[0107] In Examples 1-4, as the modifier dosage increased from 1.4% to 4.0% of the zinc powder weight, the oil absorption value of the zinc powder decreased from 16.2 g / 100g to 12.9-13.0 g / 100g, and the dispersibility gradually improved. Simultaneously, the neutral salt spray performance of the coating increased from 1424h to 3200h, significantly extending the corrosion protection life. Adhesion jumped from 9.7 MPa to 13.2 MPa when the modifier dosage reached 4.0%, indicating a substantial increase in interfacial bonding. VOC emissions showed a trend of first increasing and then decreasing, reaching 245 g / L at 3.5% dosage and decreasing to 221 g / L at 4.0%, generally meeting environmental protection requirements.

[0108] Examples 1-4, 10, and 11 use conventional particle size zinc powder (D50 = 21-24 μm). After modification, the coatings generally have a neutral salt spray performance of ≥1960h, with a maximum of 3500h, making them suitable for marine engineering, heavy equipment, and other scenarios with extremely high requirements for corrosion resistance lifespan. Example 5 uses small particle size zinc powder (D50 = 5-10 μm), which, after modification with KH-550, meets the requirements for long-term corrosion resistance, making it suitable for fine coating and complex structural components, scenarios with high requirements for coating smoothness. Examples 6-9 use medium particle size zinc powder (D50 = 16-19 μm), which, when combined with fluorocarbon surfactants or composite modification, results in lower VOC emissions, making them suitable for coating projects with high environmental priority.

[0109] Examples 1-6 use a combination of low-viscosity resins E-20 and E-51, while Examples 7-10 use a combination of high-solids resins E-44 and E-51. The coatings prepared with the latter have lower VOC emissions and better anti-corrosion performance.

[0110] Examples 2-6 show that AGE allyl glycidyl ether has a more significant VOCs reduction effect compared to the C12-14 alkyl glycidyl ether in Example 1, which helps to increase the solids content of the coating.

[0111] In summary, Examples 8-9, using fluorocarbon surfactants for modification, or Example 11, using composite modification combined with E-44 and E-51 high-solids resin systems and AGE reactive diluent, can control VOC emissions to 170-182 g / L. Example 11, using a composite modification of KH-560, titanate ester, and dispersant, or Examples 3-4, using high-dosage KH-560 modification, can achieve a neutral salt spray time of 3200-3500 hours. Example 10, using titanate ester coupling agent modification, or Example 4, using high-dosage KH-560 modification, can achieve a coating adhesion of 10.9-13.2 MPa. Example 5, using KH-550 silane coupling agent modification, can solve the problem of small-particle zinc powder agglomeration and meet the requirements of fine coating.

[0112] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for modifying flake zinc powder, characterized in that, Includes the following steps: The flaky zinc powder was stirred at a speed of 10~40 r / min. During the stirring process, the modified dispersion was sprayed onto it. After atomization, the flaky zinc powder was transferred to a horizontal ball mill and dispersed for 1~3 hours at a speed of 40~120 r / min using glass beads as a grinding aid. After sieving, the modified flaky zinc powder was obtained. The modified dispersion includes a dispersant and a modifier, wherein the modifier is selected from at least one of silane coupling agents, titanate coupling agents, and fluorocarbon surfactants.

2. The method for modifying flake zinc powder according to claim 1, characterized in that, The amount of the modified dispersion is 0.5% to 4% of the weight of the flake zinc powder, and the mass ratio of the dispersant to the modifier is 1:(1 to 3).

3. The method for modifying flake zinc powder according to claim 1, characterized in that, The process of stirring the flaky zinc powder at a speed of 10-40 r / min, and spraying the atomized modified dispersion onto it during the stirring process, specifically includes: Add the flake zinc powder to the conical double ribbon mixer and stir at a speed of 10~40 r / min. During the stirring process, spray the modified dispersion liquid into the flake zinc powder through the atomizing nozzle of the conical double ribbon mixer at a pressure of 0.1~0.4 MPa for 8~25 min. Then continue stirring at a speed of 25 r / min for 10 minutes.

4. The method for modifying flake zinc powder according to claim 1, characterized in that, The flaky zinc powder has a D50 particle size of 5~45μm and a zinc content of >88%; the glass beads have a particle size of 3~10mm and the mass ratio of glass beads to flaky zinc powder is (4~10):

1.

5. The method for modifying flake zinc powder according to claim 1, characterized in that, The modified dispersion also includes a diluent, the amount of which is 10% to 30% of the total weight of the modified dispersion.

6. A modified flake zinc powder, characterized in that, It is prepared by the modification method of the flake zinc powder according to any one of claims 1 to 5.

7. An anti-corrosion coating, characterized in that, by weight Includes the following components: 18-45 parts modified flake zinc powder, 30-65 parts pigments and fillers, 2-4 parts additives, 7-35 parts epoxy resin, 2-10 parts epoxy reactive diluent, 2-10 parts petroleum resin, 8-20 parts diluent and 5-20 parts modified amine curing agent; The modified flaky zinc powder is prepared by the modification method of the flaky zinc powder according to any one of claims 1 to 5, or is the modified flaky zinc powder according to claim 6.

8. The anti-corrosion coating according to claim 7, characterized in that, The pigments and fillers are selected from at least one of ultrafine barium sulfate, mica iron oxide powder, glass flakes, and mica powder.

9. The anti-corrosion coating according to claim 7, characterized in that, The epoxy resin is selected from at least one of E-20, E-44 and E-51; the petroleum resin is selected from at least one of C5 / C9 copolymer petroleum resin and C3 / 5 petroleum resin; the epoxy reactive diluent is selected from at least one of allyl glycidyl ether and C12-C14 alkyl glycidyl ether.

10. A method for preparing an anti-corrosion coating, characterized in that, Includes the following steps: S1. Mix the modifier and dispersant according to the preset mass ratio, stir evenly, and then put them into a liquid storage device with pressure atomization function; S2. Add the preset mass of flake zinc powder to a conical double ribbon mixer and start stirring at a speed of 10~40 r / min. During stirring, spray the atomized modified dispersion liquid evenly onto the surface of the flake zinc powder through the atomizing nozzle at a pressure of 0.1~0.4 MPa. The atomization duration is 8~25 min. After atomization, continue stirring at a speed of 25 r / min for 10 min to obtain coated flake zinc powder. S3. The coated flaky zinc powder is transferred to a horizontal ball mill, and glass beads with a particle size of 3~10mm are used as grinding aids. The powder is dry dispersed at a speed of 40~120r / min for 1~3h. After sieving, the modified flaky zinc powder is obtained. S4. Add modified flake zinc powder, pigments, fillers, additives, epoxy resin, epoxy reactive diluent, petroleum resin and diluent to a disperser, and stir and disperse at a speed of 600~900r / min for 60~120min to obtain the main material of component A anti-corrosion coating. S5. The modified amine curing agent is packaged separately as component B curing agent. Before use, the two components are mixed evenly according to the mass ratio of A:B = (10~15):1.

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