Glass microbeads, heavy-duty anticorrosive epoxy primer, and preparation method thereof

Abstract

The present invention discloses glass microspheres, a heavy-duty anti-corrosion epoxy primer, and a preparation method thereof. The glass microsphere-modified heavy-duty anti-corrosion epoxy primer comprises the following components by weight: Component A: 18-30 parts epoxy resin, 0-2 parts graphene, 25-50 parts zinc powder, 15-25 parts solvent, 3-5 parts non-leafing aluminum-silver paste, 2-8 parts conductive glass microspheres, 2-10 parts glass microspheres, 15-25 parts pigments and fillers, and 4.5-15 parts additives; Component B: a low-temperature epoxy curing agent; the mass ratio of Component A to Component B is 4:1 to 8:1. The present invention exhibits salt spray resistance far superior to commercially available epoxy zinc-rich coatings, exhibits excellent corrosion resistance, possesses good chloride ion absorption and excellent adhesion, and additionally provides electromagnetic shielding.

Description

Technical Field

[0001] The present invention relates to the field of epoxy coatings, in particular to glass microbeads, heavy-duty anti-corrosion epoxy primer and a preparation method thereof. Background Art

[0002] Driven by the "dual carbon" goals, my country has seen a surge in recent years in the development of numerous new energy projects, particularly offshore wind power and offshore photovoltaics, and the construction of offshore new energy bases has been booming. However, the marine environment is complex and harsh, classified as severe corrosion zones (C5, CX, or IM4) according to ISO 2944-2. Facilities and equipment are constantly exposed to harsh conditions such as high temperature, high humidity, high salt spray, and long sunshine. Marine corrosion not only shortens the operational life of equipment and facilities, posing significant safety risks, but also significantly increases construction investment and ongoing maintenance costs. Coating metal substrates with heavy-duty anti-corrosion coatings is one of the more economical and reliable methods of protection. However, most current traditional heavy-duty anti-corrosion coatings fail to fully meet the high-grade, long-life corrosion protection requirements of marine environments, particularly those in the South my country Sea. For example, offshore wind turbines should have a design life of at least 25 years, while conventional heavy-duty anti-corrosion coatings typically provide no more than 10 years of effective protection under these conditions.

[0003] Epoxy zinc-rich primers are widely used in the anti-corrosion industry at home and abroad due to the cathodic protection of zinc powder on the steel surface and the excellent chemical resistance and high adhesion of epoxy resin. However, studies have shown that due to the encapsulation and / or shielding of zinc powder by resins, pigments / fillers, and the conductive barrier formed after the elemental zinc is oxidized into zinc salts, the utilization rate of zinc in existing zinc-rich coatings (zinc powder content > 80wt%) is less than 40%, and most of it is in an ineffective dormant state. Excessive zinc powder not only increases the brittleness of the coating, but also reduces the adhesion, and the paint layer is prone to cracking under high film thickness. How to reduce the ineffective zinc content while improving the anti-corrosion performance is an important iterative direction for the zinc-rich paint industry at this stage. In recent years, people have found that if graphene is added to the primer, it can form a good conductive network with zinc powder, strengthen the conductive path, and thus to a certain extent achieve excellent cathodic protection and anti-corrosion performance under low zinc conditions. In 2020, the industry standard "Graphene Zinc Powder Coating" (HG / T 5573-2019) was officially implemented.

[0004] Patent CN 112266693A discloses a graphene zinc powder coating and its preparation method. Powdered graphene is introduced into an epoxy formulation, improving zinc powder utilization. Its labyrinthine effect enhances the coating's barrier properties. However, this patent makes it difficult to form a good conductive path. Even minor cracks or scratches in the coating may accelerate localized electrochemical corrosion. The graphene zinc powder coating contains additives and pigments and fillers. These additives include reactive diluents, defoamers, thixotropic agents, dispersants, and coupling agents. Pigments and fillers include barium sulfate, talc, and mica powder.

[0005] Patent CN 114262555 B provides a sulfonamide-silver compound-doped graphene zinc powder heavy-duty anti-corrosion coating and its preparation method. By adding the sulfonamide-silver compound to the graphene zinc powder coating, it is loaded onto the graphene surface, thereby enhancing the graphene's conductivity and improving the coating's corrosion resistance. The difficulty in implementing this patent lies in ensuring the formation of a conductive network between the zinc powder and the graphene, while reducing the amount of graphene and avoiding the risk of graphene agglomeration. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a glass microbead, a heavy-duty anti-corrosion epoxy primer and a preparation method thereof in view of the shortcomings of the existing technology. The salt spray resistance of the heavy-duty anti-corrosion epoxy primer is much higher than that of commercially available epoxy zinc-rich coatings, and it has good chloride ion absorption function and excellent coating adhesion, and additionally has an electromagnetic shielding effect.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a glass microsphere, comprising glass microspheres and an aluminum-magnesium hydrotalcite modified layer coated on the surface of the glass microspheres.

[0008] Glass microspheres, particularly hollow glass microspheres, are lightweight, hollow spherical fillers with low oil absorption. They can reduce the amount of resin used in coatings, adjust system viscosity, and improve fluidity. These functional fillers, with stable physical and chemical properties, excellent barrier properties, and highly modifiable surface properties, possess a particle size similar to zinc powder, and hold great promise for application in anti-corrosion coatings.

[0009] Chloride-absorbing glass microspheres are used in heavy-duty anti-corrosion epoxy primers, giving the coating excellent barrier and chloride-ion absorption capabilities. The coating's corrosion resistance is far superior to currently commercially available epoxy coatings. First, the chloride-absorbing glass microspheres have an anti-penetration effect. Combined with their wide particle size distribution and tighter packing than flaky fillers, they can reduce the porosity in the coating, slowing the permeation of water and oxygen, effectively blocking the galvanic cell effect, and slowing the rate of steel corrosion. Second, the unique intercalation structure of the aluminum-magnesium hydrotalcite on the surface of the glass microspheres effectively fixes and absorbs chloride ions, displacing anions with corrosion-inhibiting properties—properties not possessed by traditional epoxy coatings.

[0010] Preferably, the aluminum-magnesium hydrotalcite modified layer is a nano-aluminum-magnesium hydrotalcite modified layer.

[0011] In a preferred embodiment of the present invention, the glass microsphere preparation method comprises the following steps: ball-milling a hydrotalcite anti-rust pigment, adding the hydrotalcite and hollow glass microspheres to an ethanol-water solution containing 0.5-1.5% by weight of a silane coupling agent, and uniformly dispersing the mixture. The mixture is then rinsed with deionized water and then dried to obtain the glass microspheres. This method is simple, efficient, and convenient for production.

[0012] Aluminum magnesium hydrotalcite (hydrotalcite), also known as hydrated magnesium aluminate carbonate, is a natural mineral that contains aluminum and magnesium.

[0013] The present invention also discloses a glass microbead modified heavy-duty anti-corrosion epoxy primer, comprising the following components in parts by weight:

[0014] Component A: 18-30 parts of epoxy resin, 0-2 parts of graphene, 25-50 parts of zinc powder, 15-25 parts of solvent, 3-5 parts of non-leafing aluminum-silver paste, 2-8 parts of conductive functional glass microspheres, 2-10 parts of glass microspheres, 15-25 parts of pigments and fillers, and 4.5-15 parts of additives;

[0015] Component B: low temperature epoxy curing agent;

[0016] The mass ratio of the component A to the component B is 4:1 to 8:1.

[0017] Compared to conventional epoxy-graphene zinc powder coatings, heavy-duty corrosion-resistant epoxy primers modified with conductive glass microspheres and chloride-absorbing glass microspheres fully activate the zinc powder while further reducing the amount of graphene required, effectively preventing coating performance degradation caused by graphene aggregation. The conductive glass microspheres form a conductive network with the zinc powder particles, which, with the assistance of graphene, further activates the zinc powder. This allows for full cathodic protection with minimal or no graphene addition, thus preventing the accelerated corrosion of metal substrates that can occur in conventional graphene-epoxy coatings due to graphene aggregation.

[0018] Chloride-absorbing glass microspheres have excellent chloride ion absorption capacity, further enhancing corrosion resistance. Conductive and chloride-absorbing glass microspheres offer anti-penetration properties. Combined with their wide particle size distribution and denser packing than flake fillers, they reduce porosity in the coating, slowing water and oxygen penetration, effectively blocking the galvanic effect and slowing steel corrosion.

[0019] When graphene is added alone as an electromagnetic shielding agent to coatings, its shielding effectiveness is low due to its limited conductivity, the amount required is large, and it easily agglomerates. Conductive glass microbeads, with their unique hollow structure and excellent conductivity, can achieve excellent electromagnetic shielding effects when combined with a small amount of graphene to form a network.

[0020] The present invention can select solvents and additives in the prior art according to the performance requirements of the primer. The conductive functional glass microspheres can adopt existing conductive glass microspheres. Among them, the low-temperature epoxy curing agent is a chemical substance that can cure epoxy resin at a relatively low temperature. This curing agent is usually used for construction in a low-temperature environment, such as in winter or in areas with low temperatures (<5°C / 40°F). The main components of non-leafing aluminum silver paste are flaky aluminum particles and petroleum solvent. It is in a paste form, can be completely wetted by the paint, and is evenly distributed throughout the paint film. It is an anti-corrosion pigment with excellent performance.

[0021] In a preferred embodiment of the present invention, the conductive functional glass microspheres are one or both of chemically electroplated hollow glass microspheres and chemically aluminum-plated solid glass microspheres, wherein the chemically electroplated hollow glass microspheres include chemically silver-plated hollow glass microspheres and chemically nickel-plated hollow glass microspheres, and the density of the conductive functional glass microspheres is 0.40 to 5.00 g / cm 3 .

[0022] The density of the chemically aluminum-plated solid glass microspheres is similar to that of zinc powder (7.14 g / cm 3 ) and similar particle size effectively prevent stratification due to density differences and improve the uneven dispersion that can occur in hollow glass microsphere applications. Increasing the proportion of silver-plated hollow glass microspheres can enhance the primer's electromagnetic shielding performance. Conductive glass microspheres have a unique hollow structure and excellent conductivity. When combined with a small amount of graphene, they form a "silver / nickel / aluminum-graphene" network that achieves excellent electromagnetic shielding effectiveness.

[0023] Specifically, the density of the chemically silver-plated hollow glass microspheres is 0.40 to 1.10 g / cm 3 The chemical nickel-plated hollow glass microspheres are 0.50-1.00 g / cm 3 The density of the chemically aluminum-plated solid glass microspheres is 4.00 to 5.00 g / cm 3 .

[0024] In a preferred embodiment of the present invention, the mass ratio of the aluminum-plated solid glass microspheres to the chemically electroplated hollow glass microspheres is 0-4:1-4.

[0025] Preferably, the aluminum-plated solid glass microspheres and the chemically electroplated hollow glass microspheres are used simultaneously. To avoid the problems of poor dispersibility and uneven distribution that may exist in hollow glass microspheres, solid glass microspheres with metal plating on the surface are introduced into the formula. The combination of chemically electroplated hollow glass microspheres and solid glass microspheres overcomes the problem of uneven distribution of hollow glass microspheres in individual applications to a certain extent, further exerts the surface function, and expands the application in the field of heavy corrosion protection. In order to ensure that the glass microspheres are evenly distributed around the zinc powder and avoid the floating problem caused by the single addition of hollow glass microspheres, a mixture of aluminum-plated solid glass microspheres and silver-plated hollow glass microspheres is further preferred.

[0026] In a preferred embodiment of the present invention, the particle size of the conductive glass microspheres and the chloride ion absorbing glass microspheres is 10 to 65 μm. Outside this range, a particle size that is too small can easily cause the paint viscosity to be too high, affecting application; a particle size that is too large can affect the paint fineness and thus the quality of the paint film.

[0027] In a preferred embodiment of the present invention, the graphene is a graphene nanosheet with 3 to 10 layers, the metallic zinc content of the zinc powder is not less than 96%, the particle size is 500 to 1000 mesh, and the epoxy resin is one or a combination of bisphenol A epoxy or bisphenol F epoxy, and the epoxy equivalent is 180 to 500.

[0028] Graphene nanosheets, consisting of 3 to 10 layers, can effectively assist the conductive glass microspheres in activating the zinc powder. The conductive glass microspheres and zinc powder particles form a conductive network at the micron level, which, with the assistance of nanographene, further activates the zinc powder. By leveraging the synergistic conductivity at the micron and nanometer levels, the cathodic protection effect can be fully realized with minimal or no addition of graphene, thus preventing the accelerated corrosion of the metal substrate caused by graphene agglomeration in traditional graphene epoxy coatings.

[0029] In a preferred embodiment of the present invention, the additives include the following components in parts by weight: 0.5-5 parts dispersant, 1-5 parts thixotropic agent, 1-2 parts defoamer, 1 part adhesion promoter, and 1-2 parts leveling agent. The coating prepared within this ratio range has excellent overall performance, is easy to apply, forms a uniform and smooth film, and the cured paint film has good basic properties and excellent corrosion resistance.

[0030] The present invention also discloses a method for preparing the glass microbead modified heavy-duty anti-corrosion epoxy primer, comprising the following steps:

[0031] S1. Add epoxy resin, graphene, zinc powder, non-leafing aluminum-silver paste, and additives to a solvent, stir the solvent evenly, and after fully dissolving, add abrasive sand milling, grind finely, and filter;

[0032] S2. Add conductive functional glass microbeads and glass microbeads to the solution filtered out in S1 in sequence.

[0033] The glass beads should be added last, and should be added in small amounts multiple times under low-speed stirring until they are evenly dispersed to prevent the glass beads from breaking.

[0034] A method for preparing the glass bead-modified heavy-duty anti-corrosion epoxy primer specifically comprises the following steps:

[0035] The first step is to mix the epoxy resin, dispersant, thixotropic agent, defoamer, leveling agent and solvent evenly through a high-speed disperser. After they are fully dissolved, pour them into a sand mill and add abrasive for sand grinding. Then add graphene and pigment / filler in turn, sand grind to a fineness of no more than 60μm and filter.

[0036] In the second step, zinc powder, non-leafing aluminum paste, BYK-4511 adhesion promoter, and leveling agent are added to the filtered solution in sequence under stirring in a high-speed disperser and mixed evenly.

[0037] The third step is to reduce the speed of the mixer and add the conductive functional glass beads and glass beads in sequence by adding half of the remaining material at a time.

[0038] A glass bead-modified heavy-duty anti-corrosion epoxy primer can be used on marine engineering equipment such as offshore wind power, surface photovoltaics, seawater pumped storage, cross-sea bridges, and ships.

[0039] Chloride ions, abundant in seawater due to their small radius and strong permeability, can damage the oxide film on the surface of offshore steel structures, significantly accelerating the corrosion rate of these structures. Designing an anti-corrosion system that is resistant to chloride ion penetration is also crucial for corrosion protection of offshore engineering facilities.

[0040] Preferably, in the step of preparing the glass microspheres with chloride ion absorption function, the ball milling time of the hydrotalcite anti-rust pigment is 0.5 to 1 hour.

[0041] Preferably, in the step of preparing the chloride ion-absorbing glass microspheres, the pH of the ethanol-water solution of the silane coupling agent is 3 to 5. At this pH, the hydrolysis rate of the silane coupling agent is moderate, and the resulting product is of high quality. Otherwise, the silane coupling agent fails to hydrolyze or the hydrolysis rate is uncontrollable (too fast or too slow).

[0042] Preferably, in the step of preparing chloride ion absorbing glass microspheres, the preparation method of the hollow glass microspheres modified with nano-aluminum-magnesium hydrotalcite is to uniformly disperse by ultrasonication at 55° C. to 55° C. for 0.5-1 h, and then wash with deionized water and dry for later use.

[0043] Preferably, the dispersant is at least one of BYK-9076, BYK-110, BYK-W965, and DS-9104.

[0044] Preferably, the thixotropic agent is at least one of polyamide wax, fumed silica, organic bentonite, and hydrogenated castor oil.

[0045] Preferably, the zinc powder has a metallic zinc content of not less than 96% and a particle size of 500 to 1000 meshes.

[0046] Preferably, the defoaming agent is at least one of BYK-A530, BYK-A501, BYK-066N, and BYK-A535.

[0047] Preferably, the pigment and filler is at least one of talc, sericite powder, titanium dioxide, montmorillonite, and aluminum-magnesium hydrotalcite, preferably a mixture of talc and titanium dioxide.

[0048] Preferably, the leveling agent is at least one of BYK-306, BYK-310, BYK-320, and BYK-333.

[0049] Preferably, the adhesion promoter is BYK-4511.

[0050] Preferably, the solvent is one or more of xylene, 1-methoxy-2-propanol, and n-butanol.

[0051] Preferably, the low-temperature epoxy curing agent is an amine curing agent, including at least one of phenolamine, phenolamide, and polyamide. These curing agents can cure the coating at room temperature without heating, have a moderate curing speed, and a long pot life, which is conducive to coating. The low-temperature epoxy curing agent also includes a solvent, with the mass ratio of solvent to amine curing agent being 7-8:2-3.

[0052] Patent CN 112266693A makes it difficult to form a good conductive path. Even slight cracks or scratches in the coating can accelerate localized electrochemical corrosion. The reason is that the paint film contains too little graphene, making it difficult to form a good conductive path. Therefore, reducing the amount of zinc powder requires adding more graphene to the formulation. This facilitates the formation of a direct path between the external corrosive medium and the substrate. Once the coating develops slight cracks or scratches, electrical coupling between the graphene and the protected metal occurs, potentially accelerating localized electrochemical corrosion. Furthermore, excessive addition of graphene increases the risk of graphene nanosheet agglomeration and negatively impacts the coating's viscosity and sag resistance.

[0053] Compared with the prior art, the present invention offers the following advantages: the coating exhibits excellent resistance to chloride ion penetration and corrosion resistance, making it suitable for harsh marine environments. It can fully activate zinc powder, further reducing graphene usage and improving coating performance degradation caused by graphene aggregation. With minimal or no graphene addition, the coating can fully achieve cathodic protection, thereby preventing issues such as accelerated corrosion of metal substrates caused by graphene aggregation in traditional graphene epoxy coatings. The coating also provides a certain electromagnetic shielding effect, further expanding its applications in protecting precision electronic components in harsh environments. Furthermore, the glass microspheres have low oil absorption and are completely encapsulated by the resin, resulting in a dense coating that achieves electromagnetic shielding while maintaining excellent corrosion resistance, offering dual application value for electromagnetic protection of precision electronic components in marine environments. The low zinc powder content of the present invention mitigates internal defects in the coating to a certain extent. Furthermore, the addition of glass microspheres creates numerous micrometer-sized spaces within the coating, reducing the internal stress of the coating during curing, thereby improving adhesion. Furthermore, this heavy-duty anti-corrosion epoxy primer exhibits excellent leveling and sag resistance, strong adhesion, and good mechanical properties. It has significant practical application value in the corrosion protection and electromagnetic shielding of offshore wind power, surface photovoltaic power generation, seawater pumped storage, cross-sea bridges, ships, and other marine equipment. It helps save construction time, improves coating quality, and is more adaptable to various complex workpieces and construction environments. DETAILED DESCRIPTION

[0054] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention, but the protection scope thereof should not be limited to the following examples.

[0055] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods.

[0056] Unless otherwise specified, the raw materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources.

[0057] Example 1

[0058] Chloride ion-absorbing glass microspheres include glass microspheres and a modified aluminum-magnesium hydrotalcite layer coating the surface of the glass microspheres. The chloride ion-absorbing glass microspheres are prepared by ball-milling commercially available hydrotalcite anti-rust pigment (WP, Zhejiang Fenghong) for 0.5-1 hour. The pigment, along with the hollow glass microspheres, is then added to an ethanol-water solution (pH 3-5) containing 1% silane coupling agent. The solution is ultrasonically dispersed at 60°C for 0.5 hour, rinsed with deionized water, and then dried for later use.

[0059] A glass bead-modified heavy-duty anti-corrosion epoxy primer comprises the following raw materials in parts by weight: 20 parts of epoxy E44 resin, 0.5 parts of graphene, 1.5 parts of a polyamide wax thixotropic agent, 1 part of a BYK-A530 defoaming agent, 1 part of a BYK-110 dispersant, 10 parts of talc, 10 parts of titanium dioxide, 3 parts of a non-leafing aluminum-silver paste (Changsha Zuxing, 3013#), 25 parts of zinc powder, 1 part of a BYK-4511 adhesion promoter, 1 part of a BYK-306 leveling agent, 20 parts of a mixed solvent (wherein the mass ratio of xylene to 1-methoxy-2-propanol is 4:1), 5 parts of conductive functional glass microspheres (wherein the mass ratio of aluminum-plated solid glass microspheres to nickel-plated hollow glass microspheres is 3:2), and 5 parts of chloride ion absorbing functional glass microspheres.

[0060] Add the mixed solvent and E-44 epoxy to the dispersion tank in sequence and disperse at high speed at 1000r / min to completely dissolve the resin. Then, activate the polyamide wax by high-speed dispersion at 1000r / min at 50°C for 20min. Add the defoamer and dispersant and mix well before transferring to a stainless steel dispersion tank. Replace the sanding disc with glass bead abrasive and add graphene in batches at 1000r / min. Sand and grind for 15min. Then add talcum powder and titanium dioxide in batches. After the addition is complete, increase the speed to 2000r / min and continue sanding for 10min. Filter through a filter. Subsequently, add non-leafing aluminum-silver paste, zinc powder, aluminum-plated solid glass microspheres, adhesion promoter, and leveling agent to the filtered mixture solution and disperse at 500r / min for 30min. Reduce the stirring speed to 300r / min and add nickel-plated hollow glass microspheres in small batches until completely dispersed. Finally, the chloride ion absorbing glass microbeads were slowly added to the coating in five portions, with half of the remaining amount added each time, to finally prepare component A.

[0061] Cashew nut shell oil phenol aldehyde amide and solvent are prepared in a mass ratio of 7:3 to prepare component B. When used, components A and B are mixed in a mass ratio of 5:1 to obtain a glass bead modified heavy-duty anti-corrosion epoxy primer.

[0062] Example 2

[0063] A glass bead-modified heavy-duty anti-corrosion epoxy primer comprises the following raw materials in parts by weight: 20 parts of epoxy E44 resin, 0.5 parts of graphene, 2 parts of a polyamide wax thixotropic agent, 1 part of a BYK-A501 defoamer, 1 part of a BYK-9076 dispersant, 10 parts of talc, 5 parts of titanium dioxide, 3 parts of a non-leafing aluminum-silver paste, 25 parts of zinc powder, 1 part of a BYK-4511 adhesion promoter, 1 part of a BYK-306 leveling agent, 15 parts of a mixed solvent (wherein the mass ratio of xylene to 1-methoxy-2-propanol is 4:1), 4 parts of conductive functional glass microspheres (aluminum-plated solid glass microspheres), and 8 parts of chloride ion absorbing functional glass microspheres.

[0064] Add the mixed solvent and E-44 epoxy resin to the dispersion tank in sequence and disperse at 1000 rpm to completely dissolve the resin. Then, activate the polyamide wax by dispersing at 1000 rpm at 50°C for 20 minutes. Add the defoamer and dispersant, mix thoroughly, and transfer to a stainless steel dispersion tank. Replace the sanding disc with glass beads and add the graphene in batches at 1000 rpm for 15 minutes. Then, add the talc and titanium dioxide in batches. After the additions are complete, increase the speed to 2000 rpm and continue sanding for approximately 10 minutes. Then, filter through a filter. Then, add the adhesion promoter, leveling agent, non-leafing aluminum-silver paste, zinc powder, and aluminum-coated solid glass microspheres to the filtered mixture. Disperse at 500 rpm for 30 minutes. Reduce the stirring speed to 300 rpm and slowly add the chloride ion-absorbing glass microspheres to the coating in five portions, adding half of the remaining amount each time, to produce component A.

[0065] Prepare component B by mixing cashew nut shell oil phenol aldehyde amide and solvent in a mass ratio of 7:3. When using, mix components A and B in a mass ratio of 5:1 to obtain a glass bead modified heavy-duty anti-corrosion epoxy primer.

[0066] Example 3

[0067] A glass bead-modified heavy-duty anti-corrosion epoxy primer comprises the following raw materials in parts by weight: 20 parts of epoxy E44 resin, 5 parts of epoxy E20 resin, 1 part of graphene, 1 part of polyamide wax thixotropic agent, 1 part of BYK-A535 defoaming agent, 1 part of BYK-9076 dispersant, 2 parts of DS-9104 dispersant, 20 parts of talc, 3 parts of titanium dioxide, 4 parts of non-leafing aluminum-silver paste, 50 parts of zinc powder, 1 part of BYK-4511 adhesion promoter, 1 part of BYK-306 leveling agent, 20 parts of a mixed solvent (wherein the mass ratio of xylene to 1-methoxy-2-propanol is 3:1), 8 parts of conductive functional glass microspheres (wherein the mass ratio of aluminum-plated solid glass microspheres to silver-plated hollow glass microspheres is 1:3), and 2 parts of chloride ion absorbing functional glass microspheres.

[0068] The mixed solvent was added to the E-44 epoxy and E-20 epoxy in the dispersion tank in sequence, and dispersed at a high speed of 1000 r / min to completely dissolve the resin. Subsequently, the polyamide wax was activated by high-speed dispersion at 1000 r / min at 50°C for 20 minutes. The defoamer and dispersant were added and mixed evenly before being transferred to a stainless steel dispersion tank. The sanding disc was replaced with glass bead abrasives. Graphene was added in batches at 1000 r / min and sanded for 15 minutes. Talc and titanium dioxide were then added in batches. After the addition was completed, the speed was increased to 2000 r / min and sanded for about 10 minutes. The mixture was then filtered through a filter. Subsequently, non-leafing aluminum-silver paste, zinc powder, aluminum-plated solid glass microspheres, adhesion promoter, and leveling agent were added to the filtered mixture solution and dispersed at 500 r / min for 30 minutes. The stirring speed was reduced to 300 r / min, and the silver-plated hollow glass microspheres were added in small batches until completely dispersed. Finally, the hollow glass microspheres with hydrophobic surface modification were slowly added into the coating in three portions, with half of the remaining amount added each time, to finally prepare component A.

[0069] Prepare component B by mixing cashew nut shell oil phenol aldehyde amine and solvent in a mass ratio of 7:3. When using, mix components A and B in a mass ratio of 6:1 to obtain a glass bead modified heavy-duty anti-corrosion epoxy primer.

[0070] Example 4

[0071] A glass bead-modified heavy-duty anti-corrosion epoxy primer comprises the following raw materials in parts by weight: 18 parts of epoxy E44 resin, 7 parts of bisphenol F epoxy NPEF-170 resin, 0.25 parts of graphene, 3 parts of thixotropic agent polyamide wax, 1 part of thixotropic agent fumed silica, 1 part of BYK-066N defoamer, 1 part of BYK-W965 dispersant, 10 parts of talc powder, 10 parts of mica powder, 3 parts of titanium dioxide, 5 parts of non-leafing aluminum-silver paste, 30 parts of zinc powder, 1 part of BYK-4511 adhesion promoter, 1 part of BYK-306 leveling agent, 15 parts of a mixed solvent (wherein the mass ratio of xylene to n-butanol is 4:1), 5 parts of conductive functional glass microspheres (wherein the mass ratio of aluminum-plated solid glass microspheres to nickel-plated hollow glass microspheres is 4:1), and 5 parts of chloride ion absorbing functional glass microspheres.

[0072] Add the solvent, bisphenol F epoxy, and E-44 epoxy resin to the dispersion tank and disperse at a high speed of 1000 r / min to completely dissolve the resin. Subsequently, the polyamide wax and fumed silica are activated by high-speed dispersion at 1000 r / min at 50°C for 20 minutes. Add the defoamer and dispersant, mix well, and transfer to a stainless steel dispersion tank. Replace the sanding disc with glass beads and add graphene in batches at 1000 r / min. Sand and grind for 15 minutes. Then add the pigments and fillers in batches. After the addition is complete, increase the speed to 2000 r / min and continue sanding for about 10 minutes. Filter through a filter. Subsequently, add non-leafing aluminum silver paste, zinc powder, aluminum-plated solid glass microspheres, adhesion promoter, and leveling agent to the filtered mixture solution and disperse at 500 r / min for 30 minutes. Reduce the stirring speed to 300 r / min and add nickel-plated hollow glass microspheres in small batches until completely dispersed. Finally, 5 parts of chloride ion absorbing glass microbeads were slowly added into the coating in three portions, with half of the remaining amount added each time, to finally prepare component A.

[0073] Prepare component B by mixing polyamide curing agent 651 and solvent in a mass ratio of 4:1. When using, mix components A and B in a mass ratio of 4:1 to obtain a glass bead modified heavy-duty anti-corrosion epoxy primer.

[0074] Comparative Example 1

[0075] Based on Example 2, the chloride ion absorbing glass microspheres were replaced with unmodified hollow glass microspheres during the preparation process, and no conductive glass microspheres were added to prepare a hollow glass microsphere-modified epoxy zinc-containing primer. Comparative Example 1 includes the following raw materials in parts by weight: 20 parts of epoxy E44 resin, 0.5 parts of graphene, 2 parts of polyamide wax thixotropic agent, 1 part of BYK-A501 defoamer, 1 part of BYK-9076 dispersant, 10 parts of talc, 5 parts of titanium dioxide, 3 parts of non-leafing aluminum-silver paste, 25 parts of zinc powder, 1 part of BYK-4511 adhesion promoter, in a mass ratio of 1:1, 1 part of BYK-306 leveling agent, 15 parts of a mixed solvent (wherein the mass ratio of xylene to n-butanol is 4:1), and 10 parts of unmodified hollow glass microspheres.

[0076] The mixed solvent and E-44 epoxy resin were added to the dispersion tank in sequence and dispersed at a high speed of 1000 r / min to completely dissolve the resin. Subsequently, the polyamide wax was activated by high-speed dispersion at 1000 r / min at 50°C for 20 minutes. The defoamer and dispersant were added and mixed evenly before being transferred to a stainless steel dispersion tank. The sanding disc was replaced with glass bead abrasives. Graphene was added in batches at 1000 r / min and sanded for 15 minutes. Talc and titanium dioxide were then added in batches. After the addition was completed, the speed was increased to 2000 r / min and sanded for about 10 minutes. The mixture was then filtered through a filter. Subsequently, non-leafing aluminum silver paste, zinc powder, adhesion promoter, and leveling agent were added to the filtered mixture solution and dispersed at 500 r / min for 30 minutes. The stirring speed was reduced to 300 r / min, and the unmodified hollow glass microspheres were slowly added to the coating in five portions, adding half of the remaining amount each time, to finally obtain component A.

[0077] The cashew nut shell oil phenol aldehyde amide and the solvent are prepared in a mass ratio of 7:3 to prepare component B. When used, the A and B components are mixed in a mass ratio of 5:1 to obtain a glass microbead modified heavy-duty anti-corrosion epoxy primer.

[0078] Example 5

[0079] Based on Example 3, the formula does not contain graphene, and a heavy-duty anti-corrosion epoxy primer modified with functional glass microbeads is prepared. Example 5 includes the following raw materials in parts by weight: a heavy-duty anti-corrosion epoxy primer modified with functional glass microspheres, including the following raw materials in parts by weight: 20 parts of epoxy E44 resin, 5 parts of epoxy E20 resin, 1 part of polyamide wax thixotropic agent, 1 part of BYK-A535 defoaming agent, 1 part of BYK-9076 dispersant, 2 parts of DS-9104 dispersant, 20 parts of talc, 3 parts of titanium dioxide, 4 parts of non-leafing aluminum-silver paste, 50 parts of zinc powder, 1 part of BYK-4511 adhesion promoter, 1 part of BYK-306 leveling agent, 20 parts of mixed solvent (wherein the mass ratio of xylene to 1-methoxy-2-propanol is 3:1), 8 parts of conductive functional glass microspheres (wherein the mass ratio of aluminum-plated solid glass microspheres to silver-plated hollow glass microspheres is 1:3), and 2 parts of chloride ion absorption functional glass microspheres.

[0080] Add the mixed solvent, E-44 epoxy, and E-20 epoxy to the dispersion tank in sequence and disperse at 1000 rpm to completely dissolve the resin. Then, activate the polyamide wax by dispersing at 50°C and 1000 rpm for 20 minutes. Add the defoamer and dispersant, mix thoroughly, and transfer to a stainless steel dispersion tank. Replace the sanding disc with glass beads and add the abrasive. Add talc and titanium dioxide in batches. After addition, sand grind at 2000 rpm for approximately 10 minutes and filter. Then, add non-leafing aluminum-silver paste, zinc powder, aluminum-coated solid glass microspheres, adhesion promoter, and leveling agent to the filtered mixture. Disperse at 500 rpm for 30 minutes. Reduce the stirring speed to 300 rpm and add the silver-coated hollow glass microspheres in small batches until they are completely dispersed. Finally, slowly add the surface-hydrophobically modified hollow glass microspheres to the coating in three additions, adding half of the remaining amount each time, to produce component A.

[0081] Prepare component B by mixing cashew nut shell oil phenol aldehyde amine and solvent in a mass ratio of 7:3. When using, mix components A and B in a mass ratio of 6:1 to obtain a glass bead modified heavy-duty anti-corrosion epoxy primer.

[0082] Table 1 Weight parts of each component in Examples 1-5 and Comparative Example 1

[0083]

[0084]

[0085] The performance comparison of the embodiments and comparative examples of the present invention and a foreign brand epoxy zinc-rich coating (zinc content ≥ 70%) on the market is shown in Table 2 below.

[0086] Table 2. Comparison of comprehensive performance of various embodiments of the present invention and comparative examples with a foreign brand epoxy zinc-rich coating (zinc content ≥ 70%) on the market

[0087]

[0088]

[0089] It is not difficult to find from Table 2 above that there are significant differences in salt spray resistance, resistance to chloride ion penetration, adhesion, electromagnetic shielding capabilities, etc. exhibited by different coatings.

[0090] Salt spray resistance:

[0091] a. All examples and comparative examples prepared according to the formula of this patent have salt spray resistance much higher than that of commercially available epoxy zinc-rich coatings (1800h), showing excellent corrosion resistance.

[0092] b. Example 2 adds modified functional glass microspheres, while Comparative Example 1 replaces the unmodified hollow glass microspheres with the remaining components remaining basically the same. In the neutral salt spray test, the salt spray resistance of Example 2, up to 4300 hours, is significantly higher than that of Comparative Example 1 (3200 hours). The above results show that the modified functional glass microspheres effectively improve the corrosion resistance of the coating. On the one hand, this is because the conductive glass microspheres form a stronger micro-conductive path between the graphene and the zinc powder, thereby improving the utilization rate of the zinc powder; on the other hand, the chloride ion absorption functional glass microspheres in the coating effectively capture chloride ions in the test, preventing chloride ion corrosion of the steel. It should be emphasized that the excellent anti-corrosion performance of the coating material comes from the synergistic effect of functional glass microspheres, graphene and zinc powder. Example 5 does not contain graphene and only adds functional glass microspheres. Although its salt spray resistance (2900h) is significantly better than that of commercially available coatings, there is still a certain gap compared with the various examples. This confirms that functional glass microspheres can improve the corrosion resistance of the coating, and also reflects the importance of the organic combination and synergistic effect between the components in the present invention.

[0093] Chloride ion penetration:

[0094] In order to further verify the chloride ion absorption function of the coating modified with functional glass microspheres and its effect on the corrosion resistance, the chloride ion permeation of different coatings was tested. The order of the chloride ion absorption function glass microspheres in the coating from high to low is: Example 2 > Example 1 > Example 4 > Example 3 > Example 5 > Comparative Example 1. - The penetration amount gradually increased, reaching 4.92×10 -5 mg·(cm 3 d) -1 , 6.27×10 -5 mg·(cm 3 d) -1 , 9.82×10 -5 mg·(cm 3 d) -1 , 2.65×10 -4 mg·(cm 3 d) -1 , 5.63×10 -4 mg·(cm 3 d) -1 and 8.46×10 -4 mg·(cm 3 d) -1The chloride ion permeation rate in Example 2 was nearly 20 times lower than that in Comparative Example 1, which lacked chloride ion-absorbing glass microspheres. This demonstrates that the coating modified with functional glass microspheres possesses excellent chloride ion absorption capabilities. A coating's resistance to chloride ion permeability directly impacts its corrosion resistance, explaining the excellent performance of heavy-duty anti-corrosion primers modified with functional glass microspheres in salt spray testing.

[0095] Coating Adhesion:

[0096] Epoxy zinc-rich coating has a high zinc powder content, and the pigment volume concentration (PVC) in the formula exceeds the critical pigment volume concentration (CPVC). The resin cannot completely wrap the filler, resulting in large internal defects in the coating and poor adhesion (5.3MPa). In contrast, the zinc powder content of the embodiments of the present invention and the comparative example is low, which improves the internal defects of the coating to a certain extent. And with the addition of glass microbeads, many small micron-sized spaces are separated inside the coating, reducing the internal stress of the coating curing, so the adhesion of Comparative Example 2 reaches 6.8MPa. As the amount of graphene is further increased, the adhesion in Examples 1 to 4 and Comparative Example 1 is further improved to 7.5 to 8.5MPa.

[0097] Electromagnetic shielding performance:

[0098] The electromagnetic signal attenuation value in the epoxy zinc-rich coating and comparative example 1 is only ≤-3db, and there is no electromagnetic shielding effect. This is because the graphene content in comparative example 1 is low (<0.5%), and it is impossible to form an effective electromagnetic shielding network (literature reports that the minimum amount of graphene should reach 5%). Although a certain amount of conductive glass beads is added in Example 5, due to the low content and the lack of synergy of graphene, it is difficult to connect with each other to form a shielding network, so the electromagnetic signal attenuation value is only ≤-6db, which illustrates the limitations of a single electromagnetic shielding filler. In comparison, Examples 1 to 4 show more obvious electromagnetic shielding properties, especially Example 3, which adds silver-plated conductive glass beads, and the content is higher than that in Example 2, and the coating has the best electromagnetic shielding effect. The electromagnetic shielding performance of the coating is derived from the silver-graphene network formed by the conductive hollow glass beads and graphene. This coating with a unique electromagnetic shielding mechanism is very suitable for electromagnetic protection of precision equipment in harsh corrosive environments.

[0099] In addition, it can be seen from Table 2 that the addition of functional glass microspheres also gives the coating excellent anti-sagging properties (maximum wet film thickness), good leveling properties and excellent impact resistance.

[0100] In summary, the heavy-duty anti-corrosion epoxy primer modified with functional glass microbeads described in the present invention has good leveling and anti-sagging properties, excellent mechanical properties, strong adhesion, and excellent long-term anti-corrosion and electromagnetic shielding properties. It has important application value in the fields of corrosion protection, electromagnetic shielding, etc. of marine steel structures and marine engineering equipment such as offshore wind power, surface photovoltaics, seawater pumped storage, cross-sea bridges, and ships.

[0101] It should be noted that the contents of the above embodiments should be understood as intended to facilitate understanding of the performance trends of the products of the preparation method of the present invention in terms of process parameter adjustment, so as to enable those skilled in the art to more clearly grasp the innovative essence of this technical solution. All modifications in various equivalent forms are intended to fall within the scope of protection defined by the claims of this application.

Claims

1. A glass bead modified heavy-duty anti-corrosion epoxy primer, characterized in that The composition comprises the following components in parts by weight: Component A: 18-30 parts epoxy resin, 0.25-1 part graphene, 25-50 parts zinc powder, 15-25 parts solvent, 3-5 parts non-leafing aluminum-silver paste, 2-8 parts conductive glass microspheres, 2-10 parts chloride ion absorbing glass microspheres, 15-25 parts pigments and fillers, 4.5-15 parts additives; Component B: low temperature epoxy curing agent; The mass ratio of the component A to the component B is 4:1 to 8:1; The chloride ion absorbing glass microspheres include glass microspheres and an aluminum-magnesium hydrotalcite modified layer coated on the surface of the glass microspheres.

2. The glass bead modified heavy-duty anti-corrosion epoxy primer according to claim 1, characterized in that: The conductive functional glass microspheres are one or both of chemically plated hollow glass microspheres and chemically plated aluminum solid glass microspheres. The chemically plated hollow glass microspheres include chemically plated silver hollow glass microspheres and chemically plated nickel hollow glass microspheres. The density of the conductive functional glass microspheres is 0.4-5.00 g / cm 3 .

3. The glass bead modified heavy-duty anti-corrosion epoxy primer according to claim 2, characterized in that: The mass ratio of the aluminum-plated solid glass microspheres to the chemically electroplated hollow glass microspheres is 0-4:1-4.

4. The glass bead modified heavy-duty anti-corrosion epoxy primer according to claim 1, characterized in that: The particle size of the conductive functional glass microspheres and the chloride ion absorbing functional glass microspheres is 10 to 65 μm.

5. The glass bead modified heavy-duty anti-corrosion epoxy primer according to claim 1, characterized in that: The graphene is a graphene nanosheet with 3 to 10 layers, the metal zinc content of the zinc powder is not less than 96%, and the particle size is 500 to 1000 meshes, and the epoxy resin is one or a combination of bisphenol A epoxy or bisphenol F epoxy, and the epoxy equivalent is 180 to 500.

6. The glass bead modified heavy-duty anti-corrosion epoxy primer according to claim 1, characterized in that: The auxiliary agent comprises the following components in parts by weight: 0.5 to 5 parts of a dispersant, 1 to 5 parts of a thixotropic agent, 1 to 2 parts of a defoaming agent, 1 part of an adhesion promoter, and 1 to 2 parts of a leveling agent.

7. The heavy-duty anticorrosive epoxy primer modified with glass beads according to any one of claims 1 to 6, characterized in that The preparation method of the chloride ion absorbing functional glass microspheres comprises the following steps: After ball milling, the hydrotalcite anti-rust pigment is added together with hollow glass microspheres into an ethanol-water solution containing 0.5-1.5 weight percent of a silane coupling agent, dispersed evenly, washed with deionized water, and then dried to obtain the glass microspheres.

8. A method for preparing the glass microbead modified heavy-duty anti-corrosion epoxy primer according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Add epoxy resin, graphene, zinc powder, non-leafing aluminum-silver paste, and additives to a solvent, stir the solvent evenly, and after fully dissolving, add abrasive sand milling, grind finely, and filter; S2. Add conductive glass microbeads and chloride ion absorbing glass microbeads to the solution filtered out in S1 in sequence.

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