WO2024149031A1

WO2024149031A1 - Heat-conducting wave-absorbing auxiliary agent, low-temperature curing coating, heavy corrosion-resistant coating, and preparation method therefor and use thereof

Info

Publication number: WO2024149031A1
Application number: PCT/CN2023/139665
Authority: WO
Inventors: 王震宇; 吕晓明; 韩恩厚; 张良昌
Original assignee: 广东腐蚀科学与技术创新研究院
Priority date: 2023-01-09
Filing date: 2023-12-18
Publication date: 2024-07-18

Abstract

A heat-conducting wave-absorbing auxiliary agent, a low-temperature curing coating, a heavy corrosion-resistant coating, and a preparation method therefor and a use thereof, relating to the technical field of powder coatings. The heat-conducting wave-absorbing auxiliary agent is obtained by modifying MXene@BCN@ZnO by means of a modifier; MXene@BCN@ZnO comprises MXene nanoparticles, BCN nanoparticles, and ZnO nanoparticles; the MXene nanoparticles and the BCN nanoparticles are coated with the ZnO nanoparticles. The heavy corrosion-resistant coating comprises 1,1-bis(4-cyanatophenyl)ethane, surface-modified graphdiyne, MOF@MXene, and a filler; graphdiyne and the lamellae structure of MOF@MXene as well as the passivation performance thereof can synergistically improve the corrosion resistance of a metal substrate.

Description

Thermal conductive wave absorbing additive, low temperature curing coating, heavy anticorrosive coating and preparation method and application thereof

Technical Field

The present application relates to a thermal conductive wave absorbing additive, a low temperature curing coating, a heavy-duty anti-corrosion coating, and a preparation method and application thereof, and belongs to the technical field of coatings.

Background technique

In recent years, with the advent of the information age and the rapid development of wireless communication technology, communication equipment has become more and more diverse. And with the development of mobile communication technology, there are more and more communication base stations and communication equipment. However, various high-intensity electromagnetic wave radiation forces 5G communication to propagate in an environment full of electromagnetic wave radiation pollution. This electromagnetic wave pollution can generate interference signals in mobile communication transmission, thereby affecting the communication quality. At the same time, 5G signals will also interfere with the frequency bands used by other electronic devices.

At present, the protective coatings used in outdoor communication equipment such as communication cabinets, chassis, plug-in boxes, filters, etc. are mostly cured at 180-200℃. If the curing temperature is too high, some sensitive electrical components and fillers inside the communication equipment will be damaged by high temperature. The heat accumulated inside the communication equipment is mainly conducted to the air through the outer shell. Therefore, the heat dissipation demand of the outer shell material has increased significantly, and the requirements for the thermal conductivity of the material have also increased sharply. However, there are few powder coatings on the market that have excellent performance and integrate weather resistance, heat dissipation and wave absorption. Therefore, it is of great significance to study low-temperature cured thermal conductive wave absorbing powder coatings, which can not only meet the concept of energy conservation and emission reduction and dual carbon development, but also broaden the application of powder coatings.

High-temperature acid/gas, high-temperature salt water, and high-temperature corrosive water in industries such as oil drilling, refining, chemical industry, nuclear power, thermal power, environmental protection, and oceans can easily lead to corrosion damage to anti-corrosion materials, causing great harm to the safe operation of production equipment. Conventional epoxy, silicone, and phenolic coatings will degrade and damage in such severe corrosive environments after a short period of use, gradually losing adhesion to the metal, resulting in failure of coating protection.

Summary of the invention

In order to solve the above technical problems, the present application provides a thermal conductive and wave absorbing additive, a low-temperature curing coating, a heavy-duty anti-corrosion coating, and a preparation method and application thereof.

The low-temperature curing thermosetting powder coating of the present application can be applied to the field of communication equipment to solve the problems of high coating curing temperature, poor equipment heat dissipation and susceptibility to electromagnetic interference, ensuring that the communication equipment is safe during production and use. Long-term effective protection.

The method for preparing the interface passivation-type heavy-duty anti-corrosion powder coating of the present application can solve the problem of effective protection against high-temperature and high-permeability corrosive media existing in the prior art.

In order to achieve the above-mentioned invention object, this application provides the following technical solutions:

On the one hand, the present application provides a nano thermal conductive wave absorbing additive, wherein the nano thermal conductive wave absorbing additive is modified MXene@BCN@ZnO;

The modified MXene@BCN@ZnO is obtained by modifying MXene@BCN@ZnO with a modifier;

The MXene@BCN@ZnO comprises MXene nanoparticles, BCN nanoparticles and ZnO nanoparticles;

The ZnO nanoparticles cover the MXene nanoparticles and the BCN nanoparticles;

The MXene nanoparticles are multi-layer Ti ₃ C ₂ T _x nanosheets;

The thickness of the multilayer Ti ₃ C ₂ T _x nanosheet is 100-200 nm;

The purity of the multilayer Ti ₃ C ₂ T _x nanosheets is 50-68%;

The multilayer Ti ₃ C ₂ T _x nanosheet has a sheet diameter of 2 to 10 μm;

The BCN nanoparticles are prepared from activated carbon, melamine and boric acid;

The modifying agent includes tartaric acid solution.

Optionally, the activated carbon includes coconut shell activated carbon and/or fruit shell activated carbon.

In the second aspect, the present application provides a method for preparing the above-mentioned nano-thermal conductive wave absorbing additive. The preparation method synthesizes MXene@BCN by electrostatic adsorption precursor and direct pyrolysis, so that BCN nanosheets grow in situ on the MXene surface, unwinding the MXene surface to prevent its nanosheets from stacking; then a layer of ZnO nanoparticles is in situ modified on the BCN/MXene surface by a hydrothermal method to obtain a MXene@BCN@ZnO composite, and finally tartaric acid is used as a modifier to functionalize the MXene@BCN@ZnO composite to increase its carboxyl functional group content, so that it is better compatible with carboxyl polyester resin.

A method for preparing a nano thermal conductive wave absorbing additive comprises the following steps:

Step 1: Mix melamine, boric acid, water and activated carbon, and stir to obtain BCN nanoparticles;

Step 2: Mix the BCN nanoparticles with a surfactant and multilayer Ti ₃ C ₂ T _x nanosheets, introduce ammonia gas, and calcine to obtain MXene@BCN;

Step 3: Mix the MXene@BCN with a dispersant and water, add zinc nitrate and a precipitant, and place in a closed container for reaction to obtain MXene@BCN@ZnO;

Step 4: react the MXene@BCN@ZnO with a tartaric acid solution to obtain a modified MXene@BCN@ZnO, which is the nano thermal conductive wave absorbing additive.

Optionally, the mass ratio of melamine, boric acid, water and activated carbon in step 1 is 5-7:1:100-200:7-9;

The ratio of the mass of the multilayer Ti ₃ C ₂ T _x nanosheets to the total mass of melamine, boric acid and activated carbon in step 2 is 1:3-7;

The flow rate of ammonia in step 2 is 45-55 mL/min;

The calcination temperature in step 2 is 800-1200°C;

The calcination time in step 2 is 3 to 8 hours;

The dosage ratio of MXene@BCN, dispersant, water, zinc nitrate and precipitant in step 3 is 4-6:1-3:500-800:1-3:0.1-0.5;

The reaction temperature in step 3 is 100-120°C;

The reaction time in step 3 is 6 to 20 hours;

The dosage ratio of MXene@BCN@ZnO to tartaric acid solution in step 4 is 2-3 g:90-150 mL;

The molar concentration of the tartaric acid solution in step 4 is 1 to 3 mol/L;

The reaction temperature in step 4 is 60-80°C;

The reaction time in step 4 is 4 to 8 hours.

In the third aspect, the present application provides a low-temperature curing thermosetting powder coating. The modified inorganic ultrafine filler and nano-thermal conductive wave absorbing additive in the low-temperature curing thermosetting powder coating can work synergistically to jointly improve the heat dissipation and wave absorption of the powder coating; the use of the accelerator can make the powder coating have a higher degree of curing reaction, better impact resistance and salt spray resistance; at the same time, polyetheretherketone, polyketone resin, and semi-crystalline resin can jointly improve the mechanical properties of the powder coating. In short, the low-temperature curing thermosetting powder coating has excellent corrosion resistance, weather resistance, and outstanding thermal conductive wave absorbing properties.

A low-temperature curing thermosetting powder coating comprises the following components in parts by weight:

50-70 parts of polyester resin, 4-6 parts of curing agent, 0.2-5 parts of isophorone diisocyanate, 0.1-0.8 parts of accelerator, 5-20 parts of titanium dioxide, 0.1-0.5 parts of benzoin, 0.4-1.2 parts of brightener, 0.5-1.5 parts of leveling agent, 0.2-1.0 parts of defoamer, 0.3-1 parts of antioxidant, 0.5-1.5 parts of composite light stabilizer, 3-10 parts of semi-crystalline resin, 1-6 parts of polyketone resin, 3-10 parts of polyetheretherketone, 2-13 parts of modified inorganic ultrafine filler, nano 0.1 to 10 parts of thermal conductive wave absorbing agent;

The nano thermal conductive wave absorbing agent is selected from the above-mentioned nano thermal conductive wave absorbing agents.

Optionally, the polyester resin comprises a carboxyl polyester resin;

The acid value of the carboxyl polyester resin is 30 to 36 mgKOH/g;

The glass transition temperature of the carboxyl polyester resin is ≥59°C;

The viscosity of the carboxyl polyester resin at 200° C. is 4500 to 6500 mPa·s;

The curing agent includes triglycidyl isocyanurate;

The promoter includes metal salts and/or basic compounds.

Optionally, the metal salt comprises zinc acetylacetonate and/or aluminum acetylacetonate;

The basic compound includes a quaternary phosphonium salt and/or a quaternary ammonium salt;

The quaternary phosphonium salt includes triphenylethylphosphonium bromide and/or tetraphenylphosphonium phenolate;

The quaternary ammonium salt includes one or more of benzyltriethylammonium chloride, benzyltrimethylammonium bromide and choline chloride.

Optionally, the brightener includes WK701 and/or WK702.

Optionally, the leveling agent includes Resiflow PV88 and/or Resiflow PL-200A.

Optionally, the defoaming agent includes PowderAdd D700 and/or BYK964.

Optionally, the antioxidant comprises a complex of phosphites and hindered phenol antioxidants;

The composite of the phosphite and hindered phenol antioxidants includes BASF IRGANOX B900 or BASF IRGANOX B225;

The composite light stabilizer includes a benzotriazole ultraviolet absorber and a high molecular weight hindered amine light stabilizer;

The mass ratio of the benzotriazole ultraviolet absorber to the high molecular weight hindered amine light stabilizer is 1 to 3:1;

The benzotriazole ultraviolet absorber includes BASF UV327;

The high molecular weight hindered amine light stabilizer includes Chimassorb2020.

Optionally, the acid value of the semi-crystalline resin is 31 to 34 mgKOH/g;

The melting point of the semi-crystalline resin is 100 to 120°C;

The softening point of the polyketone resin is ≥75°C;

The glass transition temperature of the polyketone resin is ≥45°C;

The hydroxyl value of the polyketone resin is ≥60 mgKOH/g;

The particle size of the polyetheretherketone is 10 to 30 μm.

Optionally, the particle size of the modified inorganic ultrafine filler is ≤10 μm;

The modified inorganic ultrafine filler comprises aluminum oxide, aluminum nitride and a coupling agent;

The coupling agent covers the aluminum oxide and aluminum nitride;

The mass ratio of aluminum oxide, aluminum nitride and coupling agent is 3-5:1:0.1-0.2;

The coupling agent includes a titanate coupling agent.

Optionally, the titanate coupling agent includes isopropoxy tris(dioctyl pyrophosphate) titanate.

Optionally, the preparation method of the modified inorganic ultrafine filler comprises the following steps:

Aluminum oxide, aluminum nitride and a coupling agent are mixed, the pH is adjusted to 3-4, and stirred at 70-90° C. for 3-5 hours to obtain the modified inorganic ultrafine filler.

In a fourth aspect, the present application provides a method for preparing the above-mentioned low-temperature curing thermosetting powder coating, comprising the following steps:

Step (1) mixing the nano thermal conductive wave absorbing agent with a semi-crystalline resin and a polyketone resin, and stirring to obtain a pre-dispersion of the nano thermal conductive wave absorbing agent;

Step (2) The pre-dispersion of the nano-thermal conductive wave absorbing additive is mixed with polyester resin, curing agent, isophorone diisocyanate, accelerator, titanium dioxide, benzoin, antioxidant, composite light stabilizer, polyetheretherketone, and modified inorganic ultrafine filler, and then melt-extruded, tableted, ground, and sieved in sequence to obtain the low-temperature curing thermosetting powder coating.

Optionally, the specific operation of step (1) is: adding the nano thermal conductive wave absorbing agent, the semi-crystalline resin and the polyketone resin to ethyl acetate, stirring at high speed for 1 hour, distilling under reduced pressure, stirring at high speed for 2 hours at 110° C., and then transferring to a planetary stirring vacuum degassing machine and stirring for 20 minutes to obtain a pre-dispersion of the nano thermal conductive wave absorbing agent.

In a fifth aspect, the present application provides the use of the above-mentioned low-temperature curing thermosetting powder coating in the preparation of communication equipment housing.

In a sixth aspect, the present application provides an interface passivation type heavy-duty anti-corrosion powder coating, comprising the following components in parts by weight:

Ethane-1,1-bis(4-phenylcyanate): 30.0 to 50.0 parts;

Phenolic modified epoxy resin: 10.0-20.0 parts;

Surface fluorosilane-modified graphyne nanosheets: 2.0-5.0 parts;

MOF@MXene: 5.0-15.0 parts;

Glass flakes: 10.0-20.0 parts;

The MOF@MXene is a MXene nanosheet material with a metal-organic framework material containing cobalt and nickel grown on the surface.

Optionally, the epoxy equivalent of the phenolic modified epoxy resin is 180 g/eq to 300 g/eq;

Optionally, the phenolic modified epoxy resin is NPCN-70.

Optionally, the number of layers of the surface fluorosilane-modified graphyne nanosheets is ≤10.

Optionally, the interface passivation type heavy-duty anti-corrosion powder coating further comprises:

Leveling agent: 0.5-1.5 parts;

Defoaming agent: 0.5-1.5 parts.

In a seventh aspect, the present application also proposes a method for preparing the above-mentioned interface passivation type heavy-duty anti-corrosion powder coating, comprising the following steps:

Step 1) preparing surface fluorosilane-modified graphene nanosheets: adding a 2-4 wt% perfluorodecyltriethoxysilane ethanol solution to an acetic acid aqueous solution at a pH of 4-5 to obtain a mixed solution, wherein the mass ratio of the fluorosilane ethanol solution to the acetic acid aqueous solution is 1:3-4; adding graphene nanosheets to the mixed solution to react to obtain surface fluorosilane-modified graphene nanosheets, wherein the mass ratio of the graphene nanosheets to the fluorosilane is 1:1-1.5;

Step 2) preparing MOF@MXene: etching Ti ₃ AlCN with hydrofluoric acid and ultrasonically exfoliating to obtain MXene nanosheets; mixing Co salt, Ni salt, tetrathiafulvalene-tetrabenzoic acid ligand with the MXene nanosheets, and reacting by an in-situ hydrothermal method to obtain a MXene nanosheet material with a metal-organic framework material containing cobalt and nickel grown on the surface;

Step 3) Weigh each component of the raw material and add it into a twin-screw extruder, and crush and screen it after melt extrusion to obtain a powder coating.

Optionally, after adding graphyne nanosheets to the mixed solution in step 1), the mixture is stirred at 40-60° C. for 2-4 hours; then centrifuged, and washed with anhydrous ethanol for 1-3 times; then placed in a vacuum furnace and heated at 50-70° C. for 24-36 hours; after heating, ground with a mortar to obtain surface fluorosilane-modified graphyne nanosheet powder.

Optionally, in the step 2), the molar ratio of Co salt, Ni salt, and tetrathiafulvalene-tetrabenzoic acid ligand is 1-1.5:1-1.5:8-12;

The reaction conditions of the hydrothermal reaction are 100-150° C. for 6-24 hours;

The mass ratio of the MXene nanosheets in the MOF@MXene to the metal organic framework material containing cobalt and nickel is 1:0.2-0.8.

Optionally, the raw materials of each component in step 3) are added into a twin-screw extruder, melt-mixed at 130° C. to 150° C., and then extruded, crushed and sieved to obtain a coating powder with a particle size of 30 to 40 μm.

In an eighth aspect, the present application also proposes the application of the above-mentioned interface passivation type heavy-duty anti-corrosion powder coating.

Optionally, the metal substrate is preheated in an oven at 50°C to 70°C for 20 to 30 minutes, then the interface passivation type heavy-duty anti-corrosion powder coating layer is electrostatically sprayed, and then baked at 180 to 200°C for 20 to 30 minutes, taken out and naturally cooled to room temperature to obtain an interface passivation type heavy-duty anti-corrosion powder coating.

Optionally, the metal substrate is carbon steel, aluminum, magnesium alloy, etc.

The graphyne and MOF@MXene in this coating have catalytic properties. When heated and baked at 180-200°C, they can catalyze the low-temperature curing of cyanate resin. Secondly, graphyne and MOF@MXene are conductive. When heated and baked, they can passivate the contacting metal substrate to form a dense oxide film, further improving the corrosion resistance of the metal. In addition, graphyne has good NaCl filtration ability and can effectively prevent ^Cl- from penetrating into the coating. Finally, graphyne and MOF@MXene are both two-dimensional structures, which can form a maze network in the coating, extend the diffusion path of the corrosive medium, and improve the corrosion resistance of the coating.

This application adopts a specific implementation scheme as follows:

Preparation of fluorosilane-modified surface-modified graphene nanosheet powder: the graphene nanosheet is a few-layer graphene nanosheet with ≤3 layers, or a multi-layer graphene nanosheet with 5 to 10 layers, and the surface modification process of the surface-modified graphene nanosheet is as follows: using acetic acid to adjust the pH value of deionized water to 4 to 5 to form an acetic acid solution, preparing a perfluorodecyltriethoxysilane ethanol solution with a concentration of 2 to 4wt%, taking a fluorosilane ethanol solution accounting for 1/4 to 1/3 of the weight of the acetic acid solution, adding the fluorosilane ethanol solution to the acetic acid solution, and stirring at room temperature for 30 to 40 minutes; adding graphene nanosheets, stirring at 40 to 60°C for 2 to 4 hours; then centrifuging, washing with anhydrous ethanol for 1 to 3 times, and heating at 50 to 70°C in a vacuum furnace for 24 to 36 hours. Grinding with a mortar to obtain fluorosilane-modified surface-modified graphene nanosheet powder.

MOF is composed of Co and Ni bimetallic central atoms and tetrathiafulvalene-tetrabenzoic acid ligands; MXene is Ti ₃ CNT _x nanosheets. The preparation process is as follows: Ti ₃ AlCN is etched with hydrofluoric acid and ultrasonically exfoliated to obtain MXene nanosheets composed of Ti ₃ CNT _x . Then, Co salt, Ni salt and tetrathiafulvalene-tetrabenzoic acid ligands are mixed with MXene nanosheets, and CN-MOF (containing MOF with cobalt and nickel) to obtain MOF@MXene core-shell structure material.

The preparation method of the interface passivation type heavy-duty anti-corrosion powder coating of the present application comprises the following specific steps:

(1) Powder preparation: 50.0-70.0 parts of ethane-1,1-bis(4-phenylcyanate), 2.0-5.0 parts of surface-modified graphyne, 5.0-15.0 parts of MOF@MXene, 10.0-20.0 parts of glass flakes, 0.5-1.5 parts of leveling agent, and 0.5-1.5 parts of defoaming agent are added into a twin-screw extruder, melt-mixed at 130°C-150°C, and extruded, and crushed and sieved to obtain a coating powder with a particle size of 30-40 μm.

(2) Preparation of coating: First, preheat the metal substrate in an oven at 50°C to 70°C for 20 to 30 min, then electrostatically spray the powder, place the sample in an oven, bake at 180 to 200°C for 20 to 30 min, take it out and cool it naturally to room temperature to obtain an interface passivation type heavy-duty anti-corrosion powder coating.

The design concept of the interface passivation type heavy-duty anti-corrosion powder coating of the present invention is:

(1) Different from the traditional physical shielding method of coating, the present invention adds special materials (graphene and MOF@MXene) with catalytic and conductive properties to the coating. When heated, the filler can passivate the metal matrix after contacting with the metal matrix, forming a dense oxide layer to prevent metal corrosion.

(2) The high efficiency filtering effect of graphyne on NaCl is utilized to prevent or delay the diffusion of corrosive media such as salt water and salt spray in the coating.

(3) Fillers such as graphyne and MOF@MXene have catalytic properties. They can reduce the curing activation energy of cyanate esters, allowing them to crosslink and cure at 180-200°C. The triazine ring crosslinking network of cyanate esters and the flaky structure of graphyne and MOF@MXene form a "maze-like" physical shielding network in the coating, further preventing the penetration of corrosive media. This coating is a passivation-type corrosion-resistant coating with good high-temperature acid corrosion resistance, bonding strength, mechanical damage resistance, and radiation resistance. Interface passivation-type heavy-duty anti-corrosion powder coatings will play an important role in the industrial field. This new composite coating with catalytic properties, passivation of metal interfaces, and the formation of a "maze-like" physical crosslinking network and other functions to improve the corrosion resistance of the coating has not been reported.

Compared with the prior art, this application has the following beneficial effects:

(1) The low-temperature curing thermosetting powder coating provided by the present application uses polyester resins and accelerators to achieve low-temperature curing, uses semi-crystalline resins to improve leveling and mechanical properties, polyketone resins to improve gloss, adhesion, and softening point, and polyetheretherketones to increase mechanical properties such as wear resistance and impact resistance. The present application combines the above components to prepare low-temperature curing powder coatings using carboxyl polyester resins and accelerators, semi-crystalline resins, polyketone resins, polyetheretherketones, etc. with high reaction activity, improves the glass transition temperature and leveling properties of the powder coating, and allows it to have good room temperature storage stability while curing at low temperatures, which can solve the problem of existing polyester powder coatings used in communication equipment. The material system cannot provide a low curing temperature while maintaining good overall performance.

(2) The nano-thermal conductive and wave-absorbing additives provided in the present application can work synergistically with the modified inorganic ultrafine fillers to give the powder coating excellent wear resistance, thermal conductivity and wave absorption, so that the protective coating for communication equipment integrates anti-corrosion, heat dissipation and wave absorption, providing a strong guarantee for the long-term stable operation of communication equipment.

(3) The interface passivation type heavy-duty anti-corrosion powder coating provided in this application does not produce VOC emissions compared to water-based or oil-based coatings.

(4) The present application prepares an interface passivation type heavy-duty anti-corrosion powder coating that can be used for a long time in a high temperature and severely corrosive environment. The coating has the advantages of heavy corrosion resistance, high impermeability, and resistance to temperature changes.

(5) This application designs a metal surface passivation strategy, which achieves passivation of the metal matrix during heating through the high electron mobility of special conductive composite materials, thereby improving the overall corrosion resistance.

(6) The Graphene filler involved in the present application can effectively filter out NaCl and prevent the penetration of Cl ^- containing corrosive media into the coating.

(7) The metal passivator used in this application is a two-dimensional material MOF@MXene, which forms a dense “maze-like” cross-linked network with the triazine ring structure of the cyanate resin, further preventing the penetration of corrosive media into the coating.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is an electron microscope image of the nano thermal conductive and wave absorbing additive of the present application before and after coating ZnO nanoparticles (Note: the left image is an electron microscope image after coating ZnO nanoparticles, and the rough part of the surface is the ZnO nanoparticles; the right image is an electron microscope image before coating ZnO nanoparticles, and BCN forms smaller nanosheets on the MXene layer structure).

FIG. 2 is an XRD diagram of Example 5 and Comparative Example 4.

Detailed ways

The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

Unless otherwise specified, the raw materials and catalysts in the examples of this application were purchased through commercial channels.

Unless otherwise specified, the analysis methods in the examples all adopt conventional settings and conventional analysis methods of instruments or equipment.

The following examples 1-4 are a method for preparing a low-temperature curing thermosetting powder coating.

Example 1

Carboxyl polyester resin: 55 parts, curing agent: 4.7 parts, isophorone diisocyanate: 0.6 parts, accelerator: 0.3 parts, titanium dioxide: 12.5 parts, benzoin: 0.3 parts, brightener: 0.7 parts, leveling agent: 1.0 parts, defoamer: 0.3 parts, antioxidant: 0.5 parts, composite light stabilizer: 0.6 parts, semi-crystalline resin: 8 parts, polyketone resin: 3 parts, polyetheretherketone: 4 parts, modified inorganic ultrafine filler: 6 parts, nano-thermal conductive wave absorbing additive: 2.5 parts.

Wherein, the acid value of the carboxyl polyester resin is 33 mgKOH/g and the glass transition temperature is 62°C;

The curing agent is triglycidyl isocyanurate;

The accelerator is a mixture of tetraphenyl phosphonium phenolate and benzyl triethyl ammonium chloride (the mass ratio of tetraphenyl phosphonium phenolate to benzyl triethyl ammonium chloride is 1:1);

The brightener is WK701;

The leveling agent is Resiflow PV88;

The defoaming agent is PowderAdd D700;

The antioxidant is BASF IRGANOX B900;

The composite light stabilizer is a mixture of BASF UV327 and Chimassorb2020 (the mass ratio of BASF UV327 to Chimassorb2020 is 2:1);

The semi-crystalline resin has an acid value of 32 mgKOH/g and a melting point of 110°C;

The hydroxyl value of the polyketone resin is 60 mgKOH/g;

The modified inorganic ultrafine filler is a coupling agent-coated modified aluminum oxide and aluminum nitride powder, with a particle size of ≤10 μm, and the preparation method is as follows:

5g of aluminum oxide and 1g of aluminum nitride powder were dried at 120°C for 3h, respectively, and dispersed in a solution of 50mL of ethanol and water in a volume ratio of 4:1, 0.18g of titanate coupling agent (isopropoxy tris(dioctyl pyrophosphate acyloxy) titanate) was added, and acetic acid was added to adjust the pH to 4, and mechanically stirred at 75°C for 4h. After suction filtration, washing, and drying at 65°C for 24h, the modified inorganic ultrafine filler was obtained;

The nano thermal conductive wave absorbing additive is a modified MXene@BCN@ZnO composite (the MXene material is a multi-layer Ti ₃ C ₂ T _x nanosheet, with a sheet thickness of about 200 nm, a purity of 60%, and a sheet diameter of 5 μm), and the preparation method is as follows:

(1) Preparation of MXene@BCN: Natural coconut shell was cut and cleaned, then heated in a muffle furnace at 300 °C for 1.5 h, ball milled for 2 h, and passed through an 80-mesh sieve to obtain the coconut shell activated carbon. 1g boric acid was dispersed in 120mL pure water, stirred at 80℃ for 20min, then 8g coconut shell activated carbon was added, and stirring was continued for 10min. 0.5g CTAB and 3g MXene were added, and after stirring evenly, it was placed in a 100℃ oven for drying for 12h. After grinding, it was placed in a tube furnace and heated to 900℃ in a nitrogen atmosphere, and ammonia (flow rate 50mL/min) was introduced for calcination for 5h. The product was taken out and washed to neutrality, and MXene@BCN was obtained after vacuum drying at 80℃ for 24h.

(2) Preparation of MXene@BCN@ZnO: 5 g MXene@BCN and 2 g polyvinyl pyrrolidone were ultrasonically dispersed in 500 mL pure water, 1.9 g zinc nitrate hexahydrate and 0.2 g hexamethylenetetramine were added, and magnetic stirring was performed for 30 min. The mixture was transferred to a hydrothermal reactor and reacted at 120 °C for 8 h. After washing and drying, MXene@BCN@ZnO was obtained, which was recorded as MBZ additive.

(3) Tartaric acid modified MBZ: Weigh 2.5g MBZ additive and 500mL DMF solution into a rotary evaporator, seal it and ultrasonicate it for 2h to obtain a suspension, measure 100mL 2mol/L tartaric acid solution and add it to the suspension and continue ultrasonicating it for 2h under sealed conditions to make it evenly dispersed, then place the suspension in a constant temperature oscillator at 60℃ for 4h, and then place it in a rotary evaporator to control the temperature at 80℃ and continue to react for 2h. After the reaction is completed, the reaction product is washed with water several times until it is neutral, and the freeze-dried product is tartaric acid modified MXene@BCN@ZnO, denoted as t-MBZ;

The preparation method of the low temperature curing thermosetting powder coating is as follows:

The nano-thermal conductive and wave absorbing additive t-MBZ, the semi-crystalline resin and the polyketone resin were added to ethyl acetate according to the formula ratio, stirred at high speed for 1 hour, distilled under reduced pressure, and then stirred at high speed for 2 hours at 110°C, transferred to a planetary stirring vacuum degassing machine and stirred for 20 minutes to obtain a pre-dispersion of t-MBZ;

The pre-dispersion of t-MBZ and other components are added to a mixer in proportion and mixed evenly, then melt-extruded, tableted, ground and passed through a 180-mesh sieve to obtain the low-temperature curing thermosetting powder coating.

Example 2

Carboxyl polyester resin: 55 parts, curing agent: 4.7 parts, isophorone diisocyanate: 0.6 parts, accelerator: 0.3 parts, titanium dioxide: 12.5 parts, benzoin: 0.3 parts, brightener: 0.7 parts, leveling agent: 1.0 parts, defoamer: 0.3 parts, antioxidant: 0.5 parts, composite light stabilizer: 0.6 parts, semi-crystalline resin: 8 parts, polyketone resin: 3 parts, polyetheretherketone: 4 parts, modified inorganic ultrafine filler: 7.5 parts, nano thermal conductive wave absorbing additive: 1.0 parts. Other component types and specific preparation steps are consistent with those in Example 1.

Example 3

Carboxyl polyester resin: 55 parts, curing agent: 4.7 parts, isophorone diisocyanate: 0.6 parts, accelerator: 0.3 parts, titanium dioxide: 12.5 parts, benzoin: 0.3 parts, brightener: 0.7 parts, leveling agent: 1.0 parts, defoamer: 0.3 parts, antioxidant: 0.5 parts, composite light stabilizer: 0.6 parts, semi-crystalline resin: 8 parts, polyketone resin: 3 parts, polyetheretherketone: 4 parts, modified inorganic ultrafine filler: 3.5 parts, nano thermal conductive wave absorbing additive: 5.0 parts. Other component types and specific preparation steps are consistent with those in Example 1.

Example 4

Carboxyl polyester resin: 60 parts, curing agent: 4.7 parts, isophorone diisocyanate: 0.8 parts, accelerator: 0.4 parts, titanium dioxide: 15 parts, benzoin: 0.3 parts, brightener: 0.5 parts, leveling agent: 1.0 parts, defoamer: 0.3 parts, antioxidant: 0.5 parts, composite light stabilizer: 1.0 parts, semi-crystalline resin: 3.0 parts, polyketone resin: 1.0 parts, polyetheretherketone: 3.0 parts, modified inorganic ultrafine filler: 6.0 parts, nano thermal conductive wave absorbing additive: 2.5 parts. The accelerator is zinc acetylacetonate.

The other components and specific preparation steps are consistent with those in Example 1.

Comparative Example 1

A thermosetting powder coating comprises the following components in parts by weight:

Carboxyl polyester resin: 55 parts, curing agent: 4.7 parts, isophorone diisocyanate: 0.6 parts, titanium dioxide: 12.5 parts, benzoin: 0.3 parts, brightener: 0.7 parts, leveling agent: 1.0 parts, defoaming agent: 0.3 parts, antioxidant: 0.5 parts, composite light stabilizer: 0.6 parts, semi-crystalline resin: 8 parts, polyketone resin: 3 parts, polyetheretherketone: 4 parts, barium sulfate filler: 8.8 parts.

The preparation method of the powder coating comprises the following process flow:

Batching → premixing → melt extrusion → tableting → grinding → sieving → powder coating finished product.

Comparative Example 2

Carboxyl polyester resin: 55 parts, curing agent: 4.7 parts, isophorone diisocyanate: 0.6 parts, accelerator: 0.3 parts, titanium dioxide: 12.5 parts, benzoin: 0.3 parts, brightener: 0.7 parts, leveling agent: 1.0 parts, Defoamer: 0.3 parts, antioxidant: 0.5 parts, composite light stabilizer: 0.6 parts, semi-crystalline resin: 8 parts, polyketone resin: 3 parts, polyetheretherketone: 4 parts, modified inorganic ultrafine filler: 6 parts, barium sulfate filler: 2.5 parts.

Comparative Example 3

Carboxyl polyester resin: 55 parts, curing agent: 4.7 parts, isophorone diisocyanate: 0.6 parts, accelerator: 0.3 parts, titanium dioxide: 12.5 parts, benzoin: 0.3 parts, brightener: 0.7 parts, leveling agent: 1.0 parts, defoaming agent: 0.3 parts, antioxidant: 0.5 parts, composite light stabilizer: 0.6 parts, semi-crystalline resin: 8 parts, polyketone resin: 3 parts, polyetheretherketone: 4 parts, nano thermal conductive wave absorbing additive: 2.5 parts, barium sulfate filler: 6 parts.

Experimental Example 1

The powder coatings of Examples 1 to 4 and Comparative Examples 1 to 3 were electrostatically sprayed on aluminum plates and steel plates, and the coating properties were tested after curing at 130°C for 25 minutes. The impact performance test standard was GB/T 1732-2020, the cross-hatch adhesion test standard was GB/T 9286-2021, the pencil hardness test standard was GB/T 6739-2006, the abrasion resistance test standard was GB/T 1768-2007, the weather resistance test standard was GB/T 1865-2009, the neutral salt spray resistance test standard was GB/T 1771-2007, the moisture and heat resistance test standard was GB/T 1740-2007, and the thermal conductivity was tested by the steady-state heat flow method, with the reference standard being ASTM D5470. The microwave absorption performance was tested according to GJB/T 5239-2004. The total spraying thickness was 500 μm and the spraying was divided into three times. After one spraying, the pre-curing was performed before the next spraying. The results are shown in Table 1.

Table 1 Powder coating properties of various embodiments and comparative examples

It can be seen from Table 1 that compared with Comparative Example 1, the powder coating of the present application has a smaller optimal reflection loss, a larger effective absorption bandwidth, and a larger thermal conductivity, indicating that the modified inorganic ultrafine filler and the nano-thermal conductive wave absorbing agent work synergistically to improve the heat dissipation and wave absorption properties of the coating, and the use of the accelerator makes the coating curing reaction degree higher, and the impact performance and salt spray resistance are better; compared with Comparative Example 2, the thermal conductivity and wave absorption performance of the powder coating of the present application are significantly better, indicating that the nano-thermal conductive wave absorbing agent contributes more significantly to these two properties; compared with Comparative Example 3, the thermal conductivity, optimal reflection loss and effective absorption bandwidth of the powder coating of the present application are significantly better, indicating that the modified inorganic ultrafine filler and the nano-thermal conductive wave absorbing agent synergistically improve the coating performance; at the same time, in the powder coating of the present application, polyetheretherketone, polyketone resin, and semi-crystalline resin can improve the mechanical properties of the coating. In summary, the powder coating of the present application has excellent corrosion resistance, weather resistance, and outstanding thermal conductivity and wave absorption properties. It can be used for outdoor protection of communication equipment, improve the heat dissipation capacity and anti-electromagnetic interference ability of the equipment, and at the same time It is very consistent with the development concept of energy conservation, emission reduction and dual carbon.

The following Examples 5-7 are a method for preparing an interface passivation type heavy-duty anti-corrosion powder coating.

Example 5

(1) In this embodiment, the composition of an interface passivation type heavy-duty anti-corrosion powder coating is as follows in parts by weight:

Ethane-1,1-bis(4-phenylcyanate): 50.0 parts;

Phenolic modified epoxy resin: 10.0 parts;

Surface modified graphyne: 4.0 parts;

MOF@MXene: 10.0 parts;

Glass flakes: 15.0 parts;

Leveling agent (Resiflow PV88): 1.0 part;

Defoaming agent (BYK961): 1.0 part;

(2) The surface modification process of surface-modified graphyne nanosheets is as follows: the pH value of deionized water is adjusted to 4.5 with acetic acid to form an acetic acid solution, a 3 wt % perfluorodecyltriethoxysilane ethanol solution is prepared, and a fluorosilane ethanol solution accounting for 1/4 of the weight of the acetic acid solution is added to the acetic acid solution and stirred at room temperature for 40 min; graphyne nanosheets are added and stirred at 50°C for 3 h; then centrifuged and washed with anhydrous ethanol for 3 times, and heated at 70°C in a vacuum furnace for 24 h; ground with a mortar to obtain fluorosilane-modified surface-modified graphyne nanosheet powder.

(3) The preparation process of MOF@MXene is as follows: Ti ₃ AlCN is etched by hydrofluoric acid and ultrasonically exfoliated to obtain Ti ₃ CNT _x MXene nanosheets. Then, 1.3 parts of Co salt (CoCl ₂ ), 1.3 parts of Ni salt (nickel chloride) and 55.0 parts of tetrathiafulvalene-tetrabenzoic acid ligand are mixed with 115.0 parts of MXene nanosheets, and CN-MOF is grown on the MXene surface by an in-situ hydrothermal method (140°C, 9h) to obtain MOF@MXene filler.

(4) Powder preparation: by weight, 60.0 parts of ethane-1,1-bis(4-phenylcyanate), 10.0 parts of phenolic modified epoxy resin, 4.0 parts of surface modified graphyne, 10.0 parts of MOF@MXene, 15.0 parts of glass flakes, 1.0 parts of leveling agent, and 1.0 parts of defoaming agent were added into a twin-screw extruder, melt-mixed at 140°C and extruded, and crushed and sieved to obtain a coating powder with a particle size of 35 μm.

(5) Preparation of coating: First, preheat the metal substrate in an oven at 50°C to 70°C for 30 min, then electrostatically spray four layers of powder, place the sample in an oven, bake at 180°C for 20 min, take it out and cool it naturally to room temperature to obtain an interface passivation type heavy-duty anti-corrosion powder coating.

Example 6

In this embodiment, the mass of surface-modified graphyne in the coating of Example 5 was changed to 2.0 parts, the mass of MOF@MXene was changed to 5.0 parts, and other parameters remained unchanged.

Example 7

In this embodiment, the mass of surface-modified graphyne in the coating of Example 5 was changed to 5.0 parts, the mass of MOF@MXene was changed to 15.0 parts, and other parameters remained unchanged.

Comparative Example 4

In this comparative example, surface-modified graphyne and MOF@MXene were not added to the coating of Example 5, and other parameters remained unchanged.

Comparative Example 5

In this comparative example, the surface-modified graphyne was not added to the coating of Example 5, and other parameters were not changed.

Comparative Example 6

In this comparative example, MOF@MXene was not added to the coating of Example 5, and other parameters remained unchanged.

Data analysis: The interface passivation type heavy-duty anti-corrosion powder coating of the present invention has a film thickness of 0.15 mm. First, we characterized the interface passivation effect of the interface passivation type heavy-duty anti-corrosion powder coating and tested the X-ray diffraction (XRD) spectra of Example 5 and Comparative Example 4. The results are shown in FIG2 .

As can be seen from Figure 2, the XRD peak position of Fe/Comparative Example 4 is the same as that of the Fe matrix, and there are no extra peaks, indicating that Comparative Example 4 did not passivate the Fe matrix; while Fe/Example 5 has a crystallization peak of _Fe2O3 near ₃₃ °, indicating that Example 5 passivates Fe; Cu/Example 5 shows a crystallization peak of pure copper, and the surface coating of Example 5 has no passivation ability on the copper matrix, while the coating of Example 5 can passivate active metals such as iron and aluminum.

After the examples 5-7 and the comparative examples 5-6 were subjected to the following corrosion treatment, the electrochemical impedance spectroscopy and mechanical properties were tested:

(1) Soak in 5 wt% sulfuric acid solution at 90°C for 1200 h;

(2) Soaking in 60°C, 3.5 wt% saline for 1320 h;

(3) Soak in a mixture of 3% hydrochloric acid and 1% hydrofluoric acid at 120°C for 720 hours.

Table 2 Comparison of electrochemical low frequency impedance and bonding strength of Examples 5-7

From the comparative data in Table 2, it can be seen that the surface-modified graphyne and MOF@MXene in Example 5 are the most appropriate amounts; when the amounts of both are small, the coating cannot have sufficient passivation effect and physical barrier performance, and the corrosion resistance of the coating is weaker than that of the coating in Example 5; when the amounts of either are too high, the dispersion in the coating is affected, which in turn reduces the corrosion resistance of the coating.

Table 3 Comparison of electrochemical low frequency impedance and bonding strength between Example 5 and Comparative Examples 5-6

From the results in Table 3, it can be seen that: (1) The surface-modified graphyne in the coating has a better protection effect on the corrosion medium containing Cl-. When the surface-modified graphyne is not added to the coating, the coating performance decreases significantly in the salt water environment. (2) The MOF@MXene in the coating has a better protection effect on acid corrosion. When the MOF@MXene is not added to the coating, the coating performance decreases significantly in the acid solution.

In summary, the results of the embodiments and comparative examples show that the interface passivation type heavy-duty anti-corrosion powder coating of the present invention has strong corrosion resistance, high penetration resistance and mechanical damage resistance, and can be used in the industrial field for the protection of production equipment with high temperature and severe corrosion.

The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical contents disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

A nano thermal conductive wave absorbing agent, characterized in that the nano thermal conductive wave absorbing agent is modified MXene@BCN@ZnO;

The modified MXene@BCN@ZnO is obtained by modifying MXene@BCN@ZnO with a modifier;

The MXene@BCN@ZnO comprises MXene nanoparticles, BCN nanoparticles and ZnO nanoparticles;

The ZnO nanoparticles cover the MXene nanoparticles and the BCN nanoparticles;

The MXene nanoparticles are multi-layer Ti 3 C 2 T x nanosheets;

The thickness of the multilayer Ti 3 C 2 T x nanosheet is 100-200 nm;

The purity of the multilayer Ti 3 C 2 T x nanosheets is 50-68%;

The multilayer Ti 3 C 2 T x nanosheet has a sheet diameter of 2 to 10 μm;

The BCN nanoparticles are prepared from activated carbon, melamine and boric acid;

The modifying agent includes tartaric acid solution.
The method for preparing a nano thermal conductive wave absorbing agent according to claim 1 is characterized in that it comprises the following steps:

Step 1: Mix melamine, boric acid, water and activated carbon, and stir to obtain BCN nanoparticles;

Step 2: Mix the BCN nanoparticles with a surfactant and multilayer Ti 3 C 2 T x nanosheets, introduce ammonia gas, and calcine to obtain MXene@BCN;

Step 3: Mix the MXene@BCN with a dispersant and water, add zinc nitrate and a precipitant, and place in a closed container for reaction to obtain MXene@BCN@ZnO;

Step 4: react the MXene@BCN@ZnO with a tartaric acid solution to obtain a modified MXene@BCN@ZnO, which is the nano thermal conductive wave absorbing additive.
The method for preparing a nano thermal conductive wave absorbing additive according to claim 2 is characterized in that:

The mass ratio of melamine, boric acid, water and activated carbon in step 1 is 5-7:1:100-200:7-9;

The ratio of the mass of the multilayer Ti 3 C 2 T x nanosheets to the total mass of melamine, boric acid and activated carbon in step 2 is 1:3-7;

The flow rate of ammonia in step 2 is 45-55 mL/min;

The calcination temperature in step 2 is 800-1200°C;

The calcination time in step 2 is 3 to 8 hours;

The mass ratio of MXene@BCN, dispersant, water, zinc nitrate and precipitant in step 3 is 4-6:1-3:500-800:1-3:0.1-0.5;

The reaction temperature in step 3 is 100-120°C;

The reaction time in step 3 is 6 to 20 hours;

The dosage ratio of MXene@BCN@ZnO to tartaric acid solution in step 4 is 2-3 g:90-150 mL;

The molar concentration of the tartaric acid solution in step 4 is 1 to 3 mol/L;

The reaction temperature in step 4 is 60-80°C;

The reaction time in step 4 is 4 to 8 hours.
A low-temperature curing thermosetting powder coating, characterized in that it comprises the following components in parts by weight:

50-70 parts of polyester resin, 4-6 parts of curing agent, 0.2-5 parts of isophorone diisocyanate, 0.1-0.8 parts of accelerator, 5-20 parts of titanium dioxide, 0.1-0.5 parts of benzoin, 0.4-1.2 parts of brightener, 0.5-1.5 parts of leveling agent, 0.2-1.0 parts of defoamer, 0.3-1 parts of antioxidant, 0.5-1.5 parts of composite light stabilizer, 3-10 parts of semi-crystalline resin, 1-6 parts of polyketone resin, 3-10 parts of polyetheretherketone, 2-13 parts of modified inorganic ultrafine filler, 0.1-10 parts of nano thermal conductive wave absorbing additive;

The nano thermal conductive wave absorbing agent is selected from the nano thermal conductive wave absorbing agent according to claim 1.
A low temperature curing thermosetting powder coating according to claim 4, characterized in that the polyester resin comprises a carboxyl polyester resin;

The acid value of the carboxyl polyester resin is 30 to 36 mgKOH/g;

The glass transition temperature of the carboxyl polyester resin is ≥59°C;

The viscosity of the carboxyl polyester resin at 200° C. is 4500 to 6500 mPa·s;

The curing agent includes triglycidyl isocyanurate;

The promoter includes metal salts and/or basic compounds.
A low-temperature curing thermosetting powder coating according to claim 4 or 5, characterized in that the antioxidant comprises a composite of phosphite and hindered phenol antioxidants;

The composite of the phosphite and hindered phenol antioxidants includes BASF IRGANOX B900 or BASF IRGANOX B225;

The composite light stabilizer includes a benzotriazole ultraviolet absorber and a high molecular weight hindered amine light stabilizer;

The mass ratio of the benzotriazole ultraviolet absorber to the high molecular weight hindered amine light stabilizer is 1 to 3:1;

The benzotriazole ultraviolet absorber includes BASF UV327;

The high molecular weight hindered amine light stabilizer includes Chimassorb2020.
A low-temperature curing thermosetting powder coating according to any one of claims 4 to 6, characterized in that the acid value of the semi-crystalline resin is 31 to 34 mgKOH/g;

The melting point of the semi-crystalline resin is 100 to 120°C;

The softening point of the polyketone resin is ≥75°C;

The glass transition temperature of the polyketone resin is ≥45°C;

The hydroxyl value of the polyketone resin is ≥60 mgKOH/g;

The particle size of the polyetheretherketone is 10 to 30 μm.
A low-temperature curing thermosetting powder coating according to any one of claims 4 to 7, characterized in that the particle size of the modified inorganic ultrafine filler is ≤10 μm;

The modified inorganic ultrafine filler comprises aluminum oxide, aluminum nitride and a coupling agent;

The coupling agent covers the aluminum oxide and aluminum nitride;

The mass ratio of aluminum oxide, aluminum nitride and coupling agent is 3-5:1:0.1-0.2;

The coupling agent includes a titanate coupling agent.
The method for preparing a low-temperature curing thermosetting powder coating according to any one of claims 4 to 8 is characterized in that it comprises the following steps:

Step (1) mixing the nano thermal conductive wave absorbing agent with a semi-crystalline resin and a polyketone resin, and stirring to obtain a pre-dispersion of the nano thermal conductive wave absorbing agent;

Step (2) The pre-dispersion of the nano-thermal conductive wave absorbing additive is mixed with polyester resin, curing agent, isophorone diisocyanate, accelerator, titanium dioxide, benzoin, antioxidant, composite light stabilizer, polyetheretherketone, and modified inorganic ultrafine filler, and then melt-extruded, tableted, ground, and sieved in sequence to obtain the low-temperature curing thermosetting powder coating.
Use of a low-temperature curing thermosetting powder coating as claimed in any one of claims 4 to 8 in the preparation of communication equipment casings.
An interface passivation type heavy-duty anti-corrosion powder coating, characterized in that it comprises the following components in parts by weight:

Ethane-1,1-bis(4-phenylcyanate): 30.0 to 50.0 parts;

Phenolic modified epoxy resin: 10.0-20.0 parts;

Surface fluorosilane-modified graphyne nanosheets: 2.0-5.0 parts;

MOF@MXene: 5.0-15.0 parts;

Glass flakes: 10.0-20.0 parts;

The MOF@MXene is a MXene nanosheet material with a metal organic framework material containing cobalt and nickel grown on the surface.
The interface passivation type heavy-duty anti-corrosion powder coating according to claim 11 is characterized in that the epoxy equivalent of the phenolic modified epoxy resin is 180 g/eq to 300 g/eq.
The interface passivation-type heavy-duty anti-corrosion powder coating according to claim 11 or 12 is characterized in that the number of layers of the surface fluorosilane-modified graphyne nanosheets is ≤10.
The interface passivation type heavy-duty anti-corrosion powder coating according to any one of claims 11 to 13 is characterized in that the interface passivation type heavy-duty anti-corrosion powder coating further comprises 0.5 to 1.5 parts of a leveling agent and 0.5 to 1.5 parts of a defoaming agent.
The method for preparing any one of the interface passivation type heavy-duty anti-corrosion powder coatings according to claims 11 to 14 is characterized in that it comprises the following steps:

Step 1) preparing surface fluorosilane-modified graphene nanosheets: adding a 2-4 wt% perfluorodecyltriethoxysilane ethanol solution to an acetic acid aqueous solution at a pH of 4-5 to obtain a mixed solution, wherein the mass ratio of the fluorosilane ethanol solution to the acetic acid aqueous solution is 1:3-4; adding graphene nanosheets to the mixed solution to react to obtain surface fluorosilane-modified graphene nanosheets, wherein the mass ratio of the graphene nanosheets to the perfluorodecyltriethoxysilane is 1:1-1.5;

Step 2) preparing MOF@MXene: etching Ti 3 AlCN with hydrofluoric acid and ultrasonically exfoliating to obtain MXene nanosheets; mixing Co salt, Ni salt, tetrathiafulvalene-tetrabenzoic acid ligand with the MXene nanosheets, and reacting by an in-situ hydrothermal method to obtain a MXene nanosheet material with a metal-organic framework material containing cobalt and nickel grown on the surface;

Step 3) Weigh each component of the raw material and add it into a twin-screw extruder, and crush and screen it after melt extrusion to obtain a powder coating.
The preparation method according to claim 15 is characterized in that, after adding graphyne nanosheets to the mixed solution in step 1), stirring at 40 to 60° C. for 2 to 4 hours; then centrifuging, and then washing with anhydrous ethanol for 1 to 3 times; then placing in a vacuum furnace and heating at 50 to 70° C. for 24 to 36 hours; after heating, grinding with a mortar to obtain surface fluorosilane-modified graphyne nanosheet powder.
The preparation method according to claim 15 or 16, characterized in that the molar ratio of the Co salt, the Ni salt and the tetrathiafulvalene-tetrabenzoic acid ligand in the step 2) is 1-1.5:1-1.5:8-12; the reaction conditions of the hydrothermal reaction are 6-24h at 100-150°C;

The mass ratio of the MXene nanosheets in the MOF@MXene to the metal organic framework material containing cobalt and nickel is 1:0.2-0.8.
The preparation method according to any one of claims 15 to 17 is characterized in that the raw materials of each component in the step 3) are added to a twin-screw extruder, melt-mixed at 130° C. to 150° C. and then extruded, and crushed and sieved to obtain a coating powder with a particle size of 30 to 40 μm.
Use of any one of the interface passivation type heavy-duty anti-corrosion powder coatings described in claims 11 to 14, or the interface passivation type heavy-duty anti-corrosion powder coatings obtained according to any one of the preparation methods of claims 15 to 18 in the preparation of anti-corrosion coatings.
The application according to claim 19 is characterized in that the metal substrate is preheated in an oven at 50°C to 70°C for 20 to 30 minutes, then the interface passivation type heavy anti-corrosion powder coating is electrostatically sprayed, and then baked at 180 to 200°C for 20 to 30 minutes, taken out and naturally cooled to room temperature to obtain an interface passivation type heavy anti-corrosion powder coating.