A high solids epoxy coating and method of making the same

Abstract

The application provides a high solid content epoxy coating and a preparation method thereof, and belongs to the technical field of coatings, and comprises the following steps: dispersing functionalized boron nitride in water, performing ultrasonic treatment, adding phytic acid and stirring, increasing temperature, adding melamine and hexanediamine and stirring, centrifuging to obtain a precipitate, and vacuum drying to obtain a boron nitride / PA-MA / EDA hybrid material; adding oxidized multi-walled carbon nanotubes into water and performing ultrasonic treatment, adding cerium nitrate hexahydrate and sodium gluconate and mixing and stirring, centrifuging to obtain a precipitate, and washing to obtain an OMWCNT-Ce-sodium gluconate composite material; adding solid epoxy resin, active diluent and mixed solvent into a reaction kettle, stirring and increasing temperature, adding liquid epoxy resin, the boron nitride / PA-MA / EDA hybrid material, the OMWCNT-Ce-sodium gluconate composite material and polycaprolactone, mixing and stirring, grinding and dispersing, and uniformly stirring after adding a curing agent to obtain the high solid content epoxy coating. The application can realize corrosion resistance and weather resistance while having good adhesion.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of paint, in particular to a high solid content epoxy paint and a preparation method thereof. BACKGROUND

[0002] Epoxy resin has excellent adhesion, thermal stability, chemical resistance and corrosion resistance, etc. It is often used in adhesive, paint, encapsulation material and composite material fields, especially in the paint industry. Traditional epoxy resin paint is generally solvent-based paint, mainly containing a large amount of organic solvents such as toluene, n-butanol, phthalate ester, etc. Due to the low boiling point and high volatility of organic solvents, the emission of a large amount of volatile organic compounds (VOC) causes serious pollution to the environment, and in the curing process, the volatilization of solvents may cause pores in the paint film, reducing the performance of the paint film.

[0003] Therefore, the development of environmentally friendly coatings has become an important development direction of the paint industry. Environmentally friendly coatings mainly include powder coatings, water-based coatings, and high solid content coatings. Powder coatings require high pretreatment and harsh application conditions; water-based coatings have the disadvantages of high brittleness, poor corrosion resistance, strict drying conditions, and short storage period; high solid content coatings still belong to solvent-based coatings, which usually add reactive diluents to reduce the amount of organic solvents, thereby reducing the emission of VOC, improving the flowability, and improving the processing performance.

[0004] High solid content epoxy paint often uses bisphenol A type epoxy resin as the main raw material, but due to the aromatic ether bond in its molecular structure, it is easy to degrade and break under the ultraviolet radiation of sunlight, resulting in poor weather resistance of the paint. In addition, due to the high solid content in high solid content epoxy paint, the viscosity of the paint is high, which makes the coating film have poor flexibility and high brittleness after curing. In alternating environments (for example, seawater is injected back and forth in the ballast tank, and the environment is dry and wet alternately), the coating film will be damaged due to the invasion of liquid media such as water, acid, alkali, and salt, resulting in the loss of coating film protection performance and further causing the rusting of the substrate. In addition, due to the greater polarity of high solid content epoxy paint than traditional epoxy resin paint, the wettability of the coating on the low surface treated substrate is poor, which makes the adhesion of the coating on the substrate poor, especially in the case of insufficient surface treatment, which can cause the adhesion of the coating film to decrease, resulting in the peeling of the coating film.

[0005] Therefore, it is necessary to provide a high solid content epoxy paint and a preparation method thereof to solve the problems existing in the prior art. SUMMARY

[0006] Therefore, the present application provides a high solid content epoxy paint and a preparation method thereof, which can achieve corrosion resistance and weather resistance while having good adhesion.

[0007] To achieve the above object, the application provides a preparation method of high solid content epoxy coating, comprising the following steps:

[0008] S1, dispersing functionalized boron nitride in water, after ultrasonic treatment, adding phytic acid and stirring, then increasing temperature, adding melamine and hexanediamine and stirring, then centrifuging to obtain the precipitate, and vacuum drying to obtain boron nitride / PA-MA / EDA hybrid material;

[0009] S2, adding the oxidized multi-walled carbon nanotube into water and ultrasonic treating, then adding cerium nitrate hexahydrate and sodium gluconate and mixing and stirring, then centrifuging to obtain the precipitate, and washing to obtain OMWCNT-Ce-sodium gluconate composite material;

[0010] S3, adding solid epoxy resin, active diluent and mixed solvent into a reaction kettle, stirring and increasing temperature, then adding liquid epoxy resin, boron nitride / PA-MA / EDA hybrid material, OMWCNT-Ce-sodium gluconate composite material and polycaprolactone and mixing and stirring, then grinding and dispersing, and then adding curing agent and stirring uniformly to obtain high solid content epoxy coating.

[0011] The present application utilizes both the phosphate group of phytic acid (PA) and the amino group of melamine (MA) / hexanediamine (EDA) to form a PA-MA / EDA network, realizes in-situ ordered assembly of PA-MA / EDA on the surface of functionalized boron nitride, and finally obtains boron nitride / PA-MA / EDA hybrid materials; the interaction between the phosphate group and the amino group in the boron nitride / PA-MA / EDA hybrid material effectively improves the reactivity of the epoxy group, thereby significantly improving the crosslinking density of the coating; this high crosslinking density reduces the pores and cracks in the coating and greatly improves the overall mechanical properties; the addition of hexanediamine introduces a flexible spacer chain, and the long-chain alkane provides molecular chain flexibility, which can effectively relieve the internal stress caused by excessively high crosslinking density; in addition, the phosphate group (PA) and the amino group (MA, EDA) in the PA-MA / EDA network form dynamic ionic crosslinking bonds through electrostatic interaction or ionic bonds, which also endows the overall material with certain self-repairing ability and reduces the risk of brittle fracture of the overall material; PA-MA / EDA enhances the interfacial bonding force of the coating and the metal substrate through multi-dentate coordination, so that it can exhibit excellent adhesion and can be applied to more harsh environments; boron nitride effectively fills the micro-pore structure inside the epoxy resin; after modification of the surface of boron nitride, its compatibility with the organic matrix is improved, so that it can be better dispersed in the organic matrix and penetrate the epoxy network, hindering the crack propagation path, and further enhancing the physical barrier properties of the overall coating, effectively preventing moisture, gas and corrosive media from penetrating to the substrate surface; in addition, the chelating ability of phytic acid in the boron nitride / PA-MA / EDA hybrid material can form a dense passivation film on the surface of the metal substrate, delaying the coating peeling caused by corrosion, and the layered structure of the boron nitride / PA-MA / EDA hybrid material can reflect ultraviolet light, which helps to improve the corrosion resistance and weather resistance of the coating.

[0012] The present application prepares an OMWCNT-Ce-sodium gluconate composite material, which is modified by cerium ions / sodium gluconate on the oxidized multi-walled carbon nanotubes (OMWCNT), and finally introduced into the resin matrix. The OH and COOH existing on the molecular structure of the OMWCNT can impart a negative charge to the OMWCNT when dispersed in water, so that the cerium cations are adsorbed to the surface of the OMWCNT; in addition, the structure of the OMWCNT is bonded to the cerium cations through π-π interaction, and the negatively charged gluconate molecules interact with the adsorbed cerium cations to form a coordination bond, thereby realizing the loading of the cerium ions / sodium gluconate on the OMWCNT. The OMWCNT provides a high specific surface area and a physical barrier while realizing the slow release of the cerium ions / sodium gluconate, the cerium ions can interact with the hydroxyl ions in the cathode region of the metal surface to form a protective precipitate layer, and the sodium gluconate interacts with the iron ions and cerium ions on the metal substrate and forms an insoluble complex, these nanoscale layers can limit the contact between the substrate and the corrosion environment, and the chelating ability of phytic acid in the boron nitride / PA-MA / EDA hybrid material forms a double-effect protection, thereby improving the overall long-acting corrosion resistance; in addition, the cerium ions have strong antioxidant effect, which can improve the oxidation resistance of the coating by capturing free radicals, and further improve the weather resistance under ultraviolet light.

[0013] The present application also adds polycaprolactone, which has a flexible high molecular chain, and the ester bond and methylene segment in the molecular chain have high flexibility. During the curing process of the epoxy resin, the polycaprolactone is embedded in the epoxy crosslinking network by physical winding, providing certain deformation ability for the overall material, and cooperating with the PA-MA / EDA network to better buffer external stress and improve the overall flexibility of the coating; in addition, in a high-temperature environment, the heat absorption performance of boron nitride and OMWCNT can act as a heat conductor to transfer heat to the surrounding polycaprolactone area more quickly, inducing a heating system, and the low-melting-point polycaprolactone melt diffuses to the crack area of the resin surface to fill and repair microcracks in the resin, avoiding brittle fracture of the coating due to high temperature.

[0014] Optionally, the functionalized boron nitride is obtained by adding 3-aminopropyl triethoxysilane and hydroxylated boron nitride to an aqueous solution of 90% volume concentration of ethanol, and stirring at 75-85℃ for 10-12h.

[0015] The present application performs surface functionalization treatment on the boron nitride, and the amino or hydroxyl groups on the surface of the treated boron nitride provide reaction anchor points for subsequent bonding with PA-MA / EDA, better realizing the grafting of PA-MA / EDA on the surface of the boron nitride and improving the grafting efficiency.

[0016] Optionally, the hydroxylated boron nitride nanosheet is added into a NaOH solution with a concentration of 5 mol / L, stirred and refluxed at 50-60 DEG C for 2 h, filtered, washed with deionized water for 3-5 times, and vacuum dried at 60-80 DEG C for 12-24 h to obtain.

[0017] The present application hydroxylates the boron nitride nanosheet, provides a reaction anchor point for the grafting of 3-aminopropyl triethoxysilane, and forms a stable B-O-Si covalent bond.

[0018] Optionally, in the step S1, the functionalized boron nitride is dispersed in deionized water, ultrasonically treated for 5-10 min, then phytic acid is added and stirred for 5-10 min, the temperature is adjusted to 65 DEG C, melamine and hexanediamine are added and stirred for 2-3 h, the precipitate is obtained by centrifugation, and the boron nitride / PA-MA / EDA hybrid material is prepared by vacuum drying at 60-70 DEG C for 12-24 h.

[0019] Optionally, in the step S2, the oxidized multi-walled carbon nanotube is added into water, ultrasonically treated for 2-5 min, then cerium nitrate hexahydrate is added, mixed and stirred under ultrasonic treatment for 3-5 h, centrifuged at a speed of 3000 rpm for 10 min, the supernatant is discarded, the precipitate is washed with deionized water for 3-5 times to obtain OMWCNT-Ce; the OMWCNT-Ce is added into water, ultrasonically treated for 2-5 min, then sodium gluconate is added, mixed and stirred under ultrasonic treatment for 2-3 h, centrifuged at a speed of 1200 rpm for 5 min, the supernatant is discarded, and the precipitate is washed with deionized water for 3-5 times to obtain an OMWCNT-Ce-sodium gluconate composite material.

[0020] Optionally, the oxidized multi-walled carbon nanotube is obtained by adding the multi-walled carbon nanotube into a mixed solution containing sulfuric acid and nitric acid, stirring, heating to 100 DEG C under reflux conditions for 24 h, adding deionized water and placing in an ice bath, stirring for 40 min, standing for 3 days, centrifuging at a speed of 4000 rpm for 10 min, discarding the supernatant, and washing the precipitate with deionized water for 5 times.

[0021] The present application uses sulfuric acid and nitric acid to introduce oxygen-containing groups mainly including carboxyl and hydroxyl groups on the surface of the multi-walled carbon nanotube, provides active sites for the adsorption of cerium ions / sodium gluconate, and improves the loading efficiency of the multi-walled carbon nanotube.

[0022] Optionally, the solid epoxy resin is a hydrogenated bisphenol A type epoxy resin, the liquid epoxy resin is a bisphenol A type epoxy resin, the active diluent is one of allyl glycidyl ether, butyl glycidyl ether, and castor oil polyglycidyl ether, the mixed solvent is propylene glycol methyl ether and butanol, and the curing agent is methyl tetrahydrophthalic anhydride and isophorone diamine.

[0023] The application uses hydrogenated bisphenol A type epoxy resin as a solid resin, instead of using traditional bisphenol A type epoxy resin, the hydrogenated bisphenol A epoxy resin is converted into a saturated six-membered ring by catalytic hydrogenation, and the conjugated double bond is eliminated to block the photodegradation reaction and reduce the oxidation site, thereby effectively reducing the risk of coating yellowing.

[0024] Specifically, the wet dispersant is model RP-5014, the leveling agent is model EFKA3777, and the defoaming agent is model byk-a530.

[0025] Optionally, in the step S3, the wet dispersant, the pigment filler and the barium sulfate are added during the mixing and stirring of the liquid epoxy resin, the boron nitride / PA-MA / EDA hybrid material, the OMWCNT-Ce-sodium gluconate composite material and the polycaprolactone, and the leveling agent and the defoaming agent are added during the uniform stirring of the curing agent.

[0026] Optionally, in the step S3, the hydrogenated bisphenol A type epoxy resin, the active diluent, the propylene glycol methyl ether and the butanol are added into a reaction kettle, the temperature is raised to 50 DEG C, high-speed stirring is carried out at a speed of 1200 r / min for 3-5 min, the bisphenol A type epoxy resin is added, and medium-speed stirring is carried out at a speed of 800-1000 r / min for 10-15 min, the boron nitride / PA-MA / EDA hybrid material, the OMWCNT-Ce-sodium gluconate composite material, the polycaprolactone, the wet dispersant, the pigment filler and the barium sulfate are added, low-speed stirring is carried out at a speed of 300 r / min for 10 min, and then the speed is gradually increased to 1500-2000 r / min for high-speed stirring for 30-45 min, the temperature is lowered to 30 DEG C, and grinding dispersion is carried out for 3 times, the methyl tetrahydrophthalic anhydride and the isophorone diamine are added, mixing and stirring are carried out at 500 rpm for 20-30 min, the leveling agent and the defoaming agent are added, and low-speed stirring is carried out at a speed of 300 r / min for 10-20 min to obtain the high-solid epoxy coating.

[0027] The application further provides a high-solid epoxy coating, which comprises the following raw materials in parts by mass: 40-55 parts of a solid epoxy resin, 8-16 parts of an active diluent, 10-15 parts of a mixed solvent, 15-30 parts of a liquid epoxy resin, 15-20 parts of a boron nitride / PA-MA / EDA hybrid material, 3-5 parts of an OMWCNT-Ce-sodium gluconate composite material, 5-15 parts of polycaprolactone and 35-50 parts of a curing agent.

[0028] The mixed solvent comprises the following raw materials in parts by mass: 7-10 parts of propylene glycol methyl ether and 3-5 parts of butanol; and the curing agent comprises the following raw materials in parts by mass: 15-20 parts of methyl tetrahydrophthalic anhydride and 20-30 parts of isophorone diamine.

[0029] The above technical solution of the application at least has the following beneficial effects:

[0030] 1、The present application forms a PA-MA / EDA network through the amino interaction of phytic acid (PA) and melamine (MA) / hexanediamine (EDA), and realizes ordered assembly on the surface of boron nitride. The hybrid material improves the reactivity of epoxy groups, enhances the crosslinking density, improves the mechanical properties and adhesion, and relieves the internal stress caused by excessive crosslinking density through the flexible chain of hexanediamine. Boron nitride improves the physical barrier properties of the coating, and the chelation of phytic acid improves the corrosion protection effect, delays corrosion and reduces photocatalytic oxidation reaction, significantly improving the corrosion protection and weather resistance of the coating.

[0031] 2、The present application prepares an OMWCNT-Ce-sodium gluconate composite material, which is modified by cerium ions and sodium gluconate on the surface of oxidized multi-walled carbon nanotubes (OMWCNT), and is introduced into a resin matrix. The OMWCNT is loaded with cerium ions and sodium gluconate to achieve slow release and form a protective sedimentation layer to limit the contact between the substrate and the corrosion environment. Sodium gluconate forms an insoluble complex with the metal surface to enhance corrosion resistance, and in combination with the chelation of phytic acid, it realizes double protection and improves long-term corrosion resistance.

[0032] 3、The present application adds polycaprolactone, which embeds into the crosslinked network during the curing process of epoxy resin through its flexible molecular chain, enhancing the flexibility and deformation ability of the coating. Polycaprolactone and PA-MA / EDA network synergistically buffer external stress. In high temperature environment, the thermal conductivity of boron nitride and OMWCNT accelerates heat transfer, and polycaprolactone melt repairs resin microcracks, further preventing brittle fracture of the coating due to high temperature, and improving the high temperature resistance of the coating. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The columnar chart of gloss of the coating film prepared for the examples and comparative examples of the present application before and after ultraviolet light aging. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described below in combination with the embodiments of the present application. The described embodiments are part of the embodiments of the present application, and all other embodiments obtained by those skilled in the art based on the described embodiments of the present application belong to the scope of protection of the present application.

[0035] Example 1

[0036] The 40 g of boron nitride nanosheets were added into 500 mL of 5 mol / L NaOH solution, stirred and refluxed at 60 °C for 2 h, suction filtered, washed with deionized water for 5 times, and vacuum dried at 80 °C for 24 h to obtain hydroxylated boron nitride; 50 mL of 3-aminopropyltriethoxysilane and 30 g of hydroxylated boron nitride were added into 90% volume concentration of aqueous ethanol solution, stirred at 85 °C for 12 h to obtain functionalized boron nitride; 30 g of functionalized boron nitride was dispersed in 1000 mL of deionized water, ultrasonically treated for 10 min, 25 g of phytic acid (PA) was added and stirred for 10 min, the temperature was adjusted to 65 °C, 40 g of melamine (MA) and 20 g of hexanediamine (EDA) were added and stirred for 3 h, the precipitate was centrifuged and vacuum dried at 70 °C for 24 h to obtain boron nitride / PA-MA / EDA hybrid material.

[0037] A 300 mL of 98% mass concentration sulfuric acid solution and 100 mL of 65% mass concentration nitric acid solution were mixed to obtain a mixed solution containing sulfuric acid and nitric acid; 7 g of multi-walled carbon nanotubes (CAS No. 308068-56-6) were added into 400 mL of the mixed solution containing sulfuric acid and nitric acid, stirred and heated to 100 °C under reflux condition for 24 h, then 2 L of deionized water was added and placed in an ice bath, stirred for 40 min, and then left to stand for 3 days, centrifuged at a speed of 4000 rpm for 10 min, the supernatant was discarded and the precipitate was washed with deionized water for 5 times to obtain oxidized multi-walled carbon nanotubes; 6 g of the oxidized multi-walled carbon nanotubes (OMWCNT) were added into 1 L of water, ultrasonically treated for 5 min, then 12 g of cerium nitrate hexahydrate was added, mixed and stirred under ultrasonic treatment for 5 h, centrifuged at a speed of 3000 rpm for 10 min, the supernatant was discarded and the precipitate was washed with deionized water for 5 times to obtain OMWCNT-Ce; 6 g of OMWCNT-Ce was added into 1 L of water, ultrasonically treated for 5 min, then 10 g of sodium gluconate was added, mixed and stirred under ultrasonic treatment for 3 h, centrifuged at a speed of 1200 rpm for 5 min, the supernatant was discarded and the precipitate was washed with deionized water for 5 times to obtain OMWCNT-Ce-sodium gluconate composite material.

[0038] Into a reaction kettle, 55 g of hydrogenated bisphenol A type epoxy resin, 16 g of castor oil polyglycidol ether, 7 g of propylene glycol methyl ether, and 3 g of butanol were added, and the temperature was raised to 50°C. The mixture was stirred at a high speed of 1200 r / min for 5 min. Then, 15 g of liquid bisphenol A type epoxy resin was added, and the mixture was stirred at a medium speed of 1000 r / min for 15 min. Then, 25 g of boron nitride / PA-MA / EDA hybrid material, 5 g of OMWCNT-Ce-sodium gluconate composite material, 15 g of polycaprolactone, 8 g of pigment and filler, 1 g of RP-5014 wetting dispersant, and 30 g of barium sulfate were added. The mixture was stirred at a low speed of 300 r / min for 10 min, and then the stirring speed was gradually increased to 2000 r / min for high-speed stirring for 45 min. The temperature was lowered to 30°C, and the mixture was ground and dispersed for 3 times. Then, 20 g of methyl tetrahydrophthalic anhydride (CAS No.: 26590-20-5) and 30 g of isophorone diamine curing agent (CAS No.: 2855-13-2) were mixed and stirred at 500 rpm for 30 min. Then, 0.6 g of EFKA3777 leveling agent and 0.5 g of byk-a530 defoaming agent were added, and the mixture was stirred at a low speed of 300 r / min for 20 min to obtain a high solid content epoxy coating.

[0039] Example 2

[0040] Into a 500 mL NaOH solution with a concentration of 5 mol / L, 40 g of boron nitride nanosheet was added, and stirred at 55°C for 2 h. The mixture was subjected to suction filtration, and washed with deionized water for 4 times. The mixture was vacuum dried at 70°C for 18 h to obtain hydroxylated boron nitride. Into a 90% volume concentration of ethanol aqueous solution, 50 mL of 3-aminopropyl triethoxysilane and 30 g of hydroxylated boron nitride were added, and stirred at 80°C for 11 h to obtain functionalized boron nitride. Into 1000 mL of deionized water, 30 g of functionalized boron nitride was dispersed, and ultrasonic treated for 8 min. Then, 20 g of phytic acid (PA) was added and stirred for 8 min. The temperature was adjusted to 65°C, and 30 g of melamine (MA) and 20 g of hexanediamine (EDA) were added and stirred for 2.5 h. The mixture was centrifuged to obtain a precipitate, and vacuum dried at 70°C for 18 h to obtain boron nitride / PA-MA / EDA hybrid material.

[0041] Mix 300 mL of a 98% mass concentration sulfuric acid solution and 100 mL of a 65% mass concentration nitric acid solution to obtain a mixed solution containing sulfuric acid and nitric acid; add 7 g of multi-walled carbon nanotubes (CAS No. 308068-56-6) to 400 mL of the mixed solution containing sulfuric acid and nitric acid, stir and heat to 100°C under reflux conditions for 24 h, add 2 L of deionized water and place in an ice bath, stir for 40 min, stand for 3 days, centrifuge at a rate of 4000 rpm for 10 min, discard the supernatant and take the precipitate, wash with deionized water 5 times to obtain oxidized multi-walled carbon nanotubes; add 5 g of the oxidized multi-walled carbon nanotubes (OMWCNT) to 1 L of water, ultrasonic treatment for 2 min, add 6 g of cerium nitrate hexahydrate, mix and stir under ultrasonic treatment for 3 h, centrifuge at a rate of 3000 rpm for 10 min, discard the supernatant and take the precipitate, wash with deionized water 3 times to obtain OMWCNT-Ce; add 5 g of OMWCNT-Ce to 1 L of water, ultrasonic treatment for 2 min, add 10 g of sodium gluconate, mix and stir under ultrasonic treatment for 2 h, centrifuge at a rate of 1200 rpm for 5 min, discard the supernatant and take the precipitate, wash with deionized water 3 times to obtain an OMWCNT-Ce-sodium gluconate composite material.

[0042] Add 50 g of hydrogenated bisphenol A type epoxy resin, 9 g of allyl glycidyl ether, 10 g of propylene glycol methyl ether, 5 g of butanol to a reaction kettle, heat to 50°C, high-speed stirring at a speed of 1200 r / min for 4 min, add 20 g of liquid bisphenol A type epoxy resin, medium-speed stirring at a speed of 900 r / min for 12 min, add 20 g of boron nitride / PA-MA / EDA hybrid material, 4 g of OMWCNT-Ce-sodium gluconate composite material, 10 g of polycaprolactone, 7 g of pigment and filler, 0.9 g of RP-5014 wetting dispersant and 28 g of barium sulfate, first low-speed stirring at a speed of 300 r / min for 10 min, then gradually increase the speed to high-speed stirring at a speed of 1800 r / min for 40 min, cool to 30°C, grind and disperse 3 times, add 18 g of methyl tetrahydrophthalic anhydride (CAS No. 26590-20-5) and 22 g of isophorone diamine curing agent (CAS No. 2855-13-2), mix and stir at a speed of 500 rpm for 25 min, add 0.5 g of EFKA3777 leveling agent and 0.4 g of byk-a530 defoaming agent, low-speed stirring at a speed of 300 r / min for 15 min to obtain a high solid content epoxy coating.

[0043] Example 3

[0044] The 40 g of boron nitride nanosheets were added into 500 mL of 5 mol / L NaOH solution, stirred and refluxed at 50 °C for 2 h, suction filtered, washed with deionized water for 3 times, and vacuum dried at 60 °C for 12 h to obtain hydroxylated boron nitride; 50 mL of 3-aminopropyltriethoxysilane and 30 g of hydroxylated boron nitride were added into 90% volume concentration of aqueous ethanol solution, stirred at 75 °C for 10 h to obtain functionalized boron nitride; 30 g of functionalized boron nitride was dispersed in 1000 mL of deionized water, ultrasonically treated for 5 min, 10 g of phytic acid (PA) was added and stirred for 5 min, the temperature was adjusted to 65 °C, 20 g of melamine (MA) and 20 g of hexanediamine (EDA) were added and stirred for 2 h, the precipitate was obtained by centrifugation, and vacuum dried at 60 °C for 12 h to obtain boron nitride / PA-MA / EDA hybrid material.

[0045] A 300 mL of 98% mass concentration sulfuric acid solution and 100 mL of 65% mass concentration nitric acid solution were mixed to obtain a mixed solution containing sulfuric acid and nitric acid; 5 g of multi-walled carbon nanotubes (CAS No. 308068-56-6) were added into 400 mL of the mixed solution containing sulfuric acid and nitric acid, stirred and heated to 100 °C under reflux condition for 24 h, 2 L of deionized water was added and placed in an ice bath, stirred for 40 min, and then left to stand for 3 days, centrifuged at a speed of 4000 rpm for 10 min, the supernatant was discarded and the precipitate was washed with deionized water for 5 times to obtain oxidized multi-walled carbon nanotubes; 4 g of the oxidized multi-walled carbon nanotubes (OMWCNT) were added into 1 L of water, ultrasonically treated for 4 min, 6 g of cerium nitrate hexahydrate was added, mixed and stirred under ultrasonic treatment for 4 h, centrifuged at a speed of 3000 rpm for 10 min, the supernatant was discarded and the precipitate was washed with deionized water for 4 times to obtain OMWCNT-Ce; 4 g of OMWCNT-Ce was added into 1 L of water, ultrasonically treated for 4 min, 8 g of sodium gluconate was added, mixed and stirred under ultrasonic treatment for 2.5 h, centrifuged at a speed of 1200 rpm for 5 min, the supernatant was discarded and the precipitate was washed with deionized water for 4 times to obtain OMWCNT-Ce-sodium gluconate composite material.

[0046] Into a reaction kettle, 40 g of hydrogenated bisphenol A type epoxy resin, 8 g of butyl glycidyl ether, 7 g of propylene glycol methyl ether, and 3 g of butanol were added, and the temperature was raised to 50°C. The mixture was stirred at a high speed of 1200 r / min for 3 min. Then, 30 g of liquid bisphenol A type epoxy resin was added, and the mixture was stirred at a medium speed of 800 r / min for 10 min. Then, 15 g of boron nitride / PA-MA / EDA hybrid material, 3 g of OMWCNT-Ce-sodium gluconate composite material, 5 g of polycaprolactone, 5 g of pigment and filler, 0.8 g of RP-5014 wetting dispersant, and 25 g of barium sulfate were added. The mixture was stirred at a low speed of 300 r / min for 10 min, and then the stirring speed was gradually increased to 1500 r / min for high-speed stirring for 30 min. The temperature was lowered to 30°C, and the mixture was ground and dispersed for 3 times. Then, 15 g of methyl tetrahydrophthalic anhydride (CAS No.: 26590-20-5) and 20 g of isophorone diamine curing agent (CAS No.: 2855-13-2) were mixed and stirred at 500 rpm for 20 min. Then, 0.4 g of EFKA3777 leveling agent and 0.3 g of byk-a530 defoaming agent were added, and the mixture was stirred at a low speed of 300 r / min for 10 min to obtain a high solid content epoxy coating.

[0047] Example 4

[0048] Into a 500 mL NaOH solution with a concentration of 5 mol / L, 40 g of boron nitride nanosheets were added, and the mixture was stirred and refluxed at 60°C for 2 h. The mixture was subjected to suction filtration, washed with deionized water for 3 times, and vacuum dried at 65°C for 20 h to obtain hydroxylated boron nitride. Then, 50 mL of 3-aminopropyl triethoxysilane and 30 g of hydroxylated boron nitride were added to an aqueous ethanol solution with a volume concentration of 90%, and the mixture was stirred at 85°C for 10 h to obtain functionalized boron nitride. Then, 30 g of functionalized boron nitride was dispersed in 1000 mL of deionized water, and the mixture was ultrasonically treated for 10 min. Then, 10 g of phytic acid (PA) was added and stirred for 5 min. The temperature was adjusted to 65°C, and 25 g of melamine (MA) and 20 g of hexanediamine (EDA) were added and stirred for 2.5 h. The mixture was centrifuged to obtain a precipitate, which was vacuum dried at 65°C for 22 h to obtain a boron nitride / PA-MA / EDA hybrid material.

[0049] Mix 300 mL of a 98% mass concentration sulfuric acid solution and 100 mL of a 65% mass concentration nitric acid solution to obtain a mixed solution containing sulfuric acid and nitric acid; add 10 g of multi-walled carbon nanotubes (CAS No. 308068-56-6) to 400 mL of the mixed solution containing sulfuric acid and nitric acid, stir and heat to 100°C under reflux conditions for 24 h, add 2 L of deionized water and place in an ice bath, stir for 40 min, stand for 3 days, centrifuge at a rate of 4000 rpm for 10 min, discard the supernatant and take the precipitate, wash with deionized water 5 times to obtain oxidized multi-walled carbon nanotubes; add 6 g of the oxidized multi-walled carbon nanotubes (OMWCNT) to 1 L of water, ultrasonic treatment for 5 min, add 10 g of cerium nitrate hexahydrate, mix and stir under ultrasonic treatment for 3 h, centrifuge at a rate of 3000 rpm for 10 min, discard the supernatant and take the precipitate, wash with deionized water 5 times to obtain OMWCNT-Ce; add 6 g of OMWCNT-Ce to 1 L of water, ultrasonic treatment for 3 min, add 12 g of sodium gluconate, mix and stir under ultrasonic treatment for 2 h, centrifuge at a rate of 1200 rpm for 5 min, discard the supernatant and take the precipitate, wash with deionized water 5 times to obtain an OMWCNT-Ce-sodium gluconate composite material.

[0050] Add 45 g of hydrogenated bisphenol A type epoxy resin, 12 g of castor oil polyglycidol ether, 10 g of propylene glycol methyl ether, 4 g of butanol to a reaction kettle, heat to 50°C, high-speed stirring at a speed of 1200 r / min for 5 min, add 25 g of liquid bisphenol A type epoxy resin, medium-speed stirring at a speed of 900 r / min for 10 min, add 18 g of boron nitride / PA-MA / EDA hybrid material, 5 g of OMWCNT-Ce-sodium gluconate composite material, 12 g of polycaprolactone, 7 g of pigment and filler, 1 g of RP-5014 wetting dispersant and 26 g of barium sulfate, first low-speed stirring at a speed of 300 r / min for 10 min, then gradually increase the speed to high-speed stirring at a speed of 1800 r / min for 35 min, cool to 30°C, grind and disperse for 3 times, add 18 g of methyl tetrahydrophthalic anhydride (CAS No. 26590-20-5) and 26 g of isophorone diamine curing agent (CAS No. 2855-13-2), mix and stir at a speed of 500 rpm for 25 min, add 0.4 g of EFKA3777 leveling agent and 0.5 g of byk-a530 defoaming agent, low-speed stirring at a speed of 300 r / min for 16 min to obtain a high solid content epoxy coating.

[0051] Example 5

[0052] The 40 g of boron nitride nanosheets were added into 500 mL of 5 mol / L NaOH solution, stirred and refluxed at 50 °C for 2 h, suction filtered, washed with deionized water for 3 times, and vacuum dried at 60 °C for 12 h to obtain hydroxylated boron nitride; 50 mL of 3-aminopropyltriethoxysilane and 30 g of hydroxylated boron nitride were added into 90% volume concentration of aqueous ethanol solution, stirred at 85 °C for 10 h to obtain functionalized boron nitride; 30 g of functionalized boron nitride was dispersed in 1000 mL of deionized water, ultrasonically treated for 5 min, 10 g of phytic acid (PA) was added and stirred for 5 min, the temperature was adjusted to 65 °C, 20 g of melamine (MA) and 20 g of hexanediamine (EDA) were added and stirred for 3 h, the precipitate was obtained by centrifugation, and vacuum dried at 60 °C for 12 h to obtain boron nitride / PA-MA / EDA hybrid material.

[0053] The 300 mL of 98% mass concentration sulfuric acid solution and 100 mL of 65% mass concentration nitric acid solution were mixed to obtain a mixed solution containing sulfuric acid and nitric acid; 5 g of multi-walled carbon nanotubes (CAS No. 308068-56-6) were added into 400 mL of the mixed solution containing sulfuric acid and nitric acid, stirred and heated to 100 °C under reflux condition for 24 h, 2 L of deionized water was added and placed in an ice bath, stirred for 40 min, and then left to stand for 3 days, centrifuged at a speed of 4000 rpm for 10 min, the supernatant was discarded and the precipitate was washed with deionized water for 5 times to obtain oxidized multi-walled carbon nanotubes; 4 g of the oxidized multi-walled carbon nanotubes (OMWCNT) were added into 1 L of water, ultrasonically treated for 3 min, 6 g of cerium nitrate hexahydrate was added, mixed and stirred under ultrasonic treatment for 4 h, centrifuged at a speed of 3000 rpm for 10 min, the supernatant was discarded and the precipitate was washed with deionized water for 4 times to obtain OMWCNT-Ce; 4 g of OMWCNT-Ce was added into 1 L of water, ultrasonically treated for 3 min, 8 g of sodium gluconate was added, mixed and stirred under ultrasonic treatment for 2.5 h, centrifuged at a speed of 1200 rpm for 5 min, the supernatant was discarded and the precipitate was washed with deionized water for 3 times to obtain OMWCNT-Ce-sodium gluconate composite material.

[0054] Into a reaction kettle, 55 g of hydrogenated bisphenol A type epoxy resin, 10 g of butyl glycidyl ether, 7 g of propylene glycol methyl ether, and 5 g of butanol were added, and the temperature was raised to 50°C. The mixture was stirred at a high speed of 1200 r / min for 5 min. Then, 15 g of liquid bisphenol A type epoxy resin was added, and the mixture was stirred at a medium speed of 800 r / min for 15 min. Then, 15 g of boron nitride / PA-MA / EDA hybrid material, 3 g of OMWCNT-Ce-sodium gluconate composite material, 15 g of polycaprolactone, 8 g of pigment and filler, 0.8 g of RP-5014 wetting dispersant, and 25 g of barium sulfate were added. The mixture was stirred at a low speed of 300 r / min for 10 min, and then the stirring speed was gradually increased to 1500 r / min for high-speed stirring for 45 min. The temperature was lowered to 30°C, and the mixture was ground and dispersed for 3 times. Then, 20 g of methyl tetrahydrophthalic anhydride (CAS No.: 26590-20-5) and 20 g of isophorone diamine curing agent (CAS No.: 2855-13-2) were mixed and stirred at 500 rpm for 20 min. Then, 0.4 g of EFKA3777 leveling agent and 0.3 g of byk-a530 defoaming agent were added, and the mixture was stirred at a low speed of 300 r / min for 10 min to obtain a high solid content epoxy coating.

[0055] Example 6

[0056] Into a 500 mL NaOH solution with a concentration of 5 mol / L, 40 g of boron nitride nanosheet was added, and stirred at 60°C for 2 h. The mixture was subjected to suction filtration, and washed with deionized water for 3 times. The mixture was vacuum dried at 80°C for 12 h to obtain hydroxylated boron nitride. Into a 90% volume concentration of ethanol aqueous solution, 50 mL of 3-aminopropyl triethoxysilane and 30 g of hydroxylated boron nitride were added, and stirred at 80°C for 12 h to obtain functionalized boron nitride. Into 1000 mL of deionized water, 30 g of functionalized boron nitride was dispersed, and ultrasonic treated for 10 min. Then, 18 g of phytic acid (PA) was added and stirred for 5 min. The temperature was adjusted to 65°C, and 35 g of melamine (MA) and 20 g of hexanediamine (EDA) were added and stirred for 2 h. The mixture was centrifuged to obtain a precipitate, and vacuum dried at 70°C for 12 h to obtain boron nitride / PA-MA / EDA hybrid material.

[0057] Mix 300 mL of a 98% mass concentration sulfuric acid solution and 100 mL of a 65% mass concentration nitric acid solution to obtain a mixed solution containing sulfuric acid and nitric acid; add 7 g of multi-walled carbon nanotubes (CAS No. 308068-56-6) to 400 mL of the mixed solution containing sulfuric acid and nitric acid, stir and heat to 100°C under reflux conditions for 24 h, then add 2 L of deionized water and place in an ice bath, stir for 40 min, stand for 3 days, centrifuge at a rate of 4000 rpm for 10 min, discard the supernatant and take the precipitate, wash with deionized water 5 times to obtain oxidized multi-walled carbon nanotubes; add 6 g of the oxidized multi-walled carbon nanotubes (OMWCNT) to 1 L of water, ultrasonic treatment for 2 min, then add 10 g of cerium nitrate hexahydrate, mix and stir under ultrasonic treatment for 5 h, centrifuge at a rate of 3000 rpm for 10 min, discard the supernatant and take the precipitate, wash with deionized water 3 times to obtain OMWCNT-Ce; add 6 g of OMWCNT-Ce to 1 L of water, ultrasonic treatment for 5 min, then add 10 g of sodium gluconate, mix and stir under ultrasonic treatment for 2 h, centrifuge at a rate of 1200 rpm for 5 min, discard the supernatant and take the precipitate, wash with deionized water 5 times to obtain an OMWCNT-Ce-sodium gluconate composite material.

[0058] Add 50 g of hydrogenated bisphenol A type epoxy resin, 15 g of castor oil polyglycidyl ether, 8 g of propylene glycol methyl ether, 5 g of butanol to a reaction kettle, heat to 50°C, high-speed stirring at a speed of 1200 r / min for 3 min, add 20 g of liquid bisphenol A type epoxy resin, medium-speed stirring at a speed of 1000 r / min for 10 min, add 18 g of boron nitride / PA-MA / EDA hybrid material, 5 g of OMWCNT-Ce-sodium gluconate composite material, 15 g of polycaprolactone, 5 g of pigment and filler, 1 g of RP-5014 wetting dispersant and 25 g of barium sulfate, first low-speed stirring at a speed of 300 r / min for 10 min, then gradually increase the stirring speed to high-speed stirring at a speed of 2000 r / min for 30 min, cool to 30°C, and perform grinding and dispersion 3 times, add 15 g of methyltetrahydrophthalic anhydride (CAS No. 26590-20-5) and 30 g of isophorone diamine curing agent (CAS No. 2855-13-2), mix and stir at a speed of 500 rpm for 30 min, add 0.4 g of EFKA3777 leveling agent and 0.5 g of byk-a530 defoaming agent, low-speed stirring at a speed of 300 r / min for 10 min to obtain a high solid content epoxy coating.

[0059] The present application also carries out comparative examples and related tests.

[0060] Comparative Example 1

[0061] The difference compared with example 1 is that no boron nitride / PA-MA / EDA hybrid material is added, and other preparation methods and components are completely the same, and finally a high solid content epoxy coating is prepared.

[0062] Comparative example 2

[0063] The difference compared with example 1 is that no polycaprolactone is added, and other preparation methods and components are completely the same, and finally a high solid content epoxy coating is prepared.

[0064] Comparative example 3

[0065] The difference compared with example 1 is that no OMWCNT-Ce-sodium gluconate composite material is added, and other preparation methods and components are completely the same, and finally a high solid content epoxy coating is prepared.

[0066] Performance test

[0067] The high solid content epoxy coatings prepared in examples 1-6 and comparative examples 1-3 are subjected to basic performance tests of mixed viscosity, non-volatile content, film drying time, flexibility, impact resistance and adhesion.

[0068] The high solid content epoxy coatings prepared in examples 1-6 and comparative examples 1-3 are subjected to basic performance tests of mixed viscosity, non-volatile content, film drying time, flexibility, impact resistance and adhesion.

[0069] The high solid content epoxy coatings prepared in examples 1-6 and comparative examples 1-3 are sprayed onto the surface of a tinplate plate meeting the requirements of national standard GB / T9271-2008 at a pressure of 0.2 MPa, the spraying time is 30 s, and the film sample is dried at 80℃ after spraying, and the impact resistance of the film sample is determined according to the method of national standard GBT1732-2020 paint film impact resistance test method; the flexibility of the film sample is determined according to the method of national standard GB / T6742-2007 paint and varnish bending test (cylinder axis); and the adhesion of the film sample is determined according to the method of national standard GBT9286-2021 paint and varnish grid test;

[0070] The test results of the non-volatile content of the above-mentioned coatings and the flexibility, impact resistance and adhesion of the film samples are shown in Table 1.

[0071]

[0072] As can be seen from Table 1, the solid content of the high solid content epoxy coatings prepared in examples 1-6 is ≥80%, the VOC content is low, and compared with comparative examples 1-3, the flexibility, impact resistance and adhesion of the film samples prepared using examples 1-6 are significantly improved.

[0073] According to the data analysis of Table 1, compared with Comparative Example 1, the addition of boron nitride / PA-MA / EDA hybrid material in Example 1 significantly improves flexibility, impact resistance and adhesion; compared with Example 1, Comparative Example 2 does not add polycaprolactone, and the flexibility is significantly reduced, which further affects the impact resistance; compared with Example 1, Comparative Example 3 lacks OMWCNT-Ce-sodium gluconate composite material, which has a certain impact on impact resistance.

[0074] The corrosion resistance and weather resistance of the coating film samples prepared using the high-solid epoxy coatings prepared in Examples 1-6 and Comparative Examples 1-3 were tested.

[0075] First, the uniformly mixed high-solid coating was prepared on the surface of the tinplate with a thickness of about 100 μm by three times of spraying-drying process, the salt spray test was carried out according to the national standard GB-T1771-2007 Determination of Resistance to Neutral Salt Spray of Pigment and Varnish, the acid and alkali resistance test was carried out according to the national standard GBT9274-1988 Determination of Resistance to Liquid Medium of Pigment and Varnish, the water resistance test was carried out according to the national standard GB / T1733-1993 Determination of Water Resistance of Paint Film, and the corrosion resistance of the coating film sample was evaluated according to the experimental results of salt spray test, water resistance and acid and alkali resistance.

[0076] The weather resistance of the coating film prepared using Examples 1-6 and Comparative Examples 1-3 was evaluated by the yellowing resistance and the gloss of the coating film before and after the artificial accelerated ultraviolet aging experiment, wherein the artificial accelerated ultraviolet aging experiment was tested according to the national standard GB / T23987-2009 Artificial Weathering of Pigment and Varnish Coatings Exposed to Fluorescent UV and Water, the substrate was selected as Q235 steel plate, the coating film with a thickness of about 100 μm was prepared using the above coating film sample preparation process, the yellowing index of the coating film sample was determined according to the standard ASTM / E313-2010, and the artificial accelerated ultraviolet aging test was carried out on the coating film sample, the artificial accelerated ultraviolet aging experiment conditions were as follows: lamp tube was UVA-340, irradiance was 0.89 W / m 2 ×nm, exposure section was 8 h drying, blackboard temperature was 60℃, 4 h condensation, blackboard temperature was 50℃, test time was 100 h; after the test, the gloss of the sample was tested, and the comparison of the gloss of the coating film sample before and after the test was shown in Figure 1 ;

[0077] The salt spray resistance of the coating film prepared using Examples 1-6 and Comparative Examples 1-3 was shown in Table 2, and the test results of acid and alkali resistance, water resistance and yellowing index were shown in Table 3.

[0078]

[0079] As shown in Table 2, Table 3 and Figure 1 It can be seen that the corrosion resistance and weather resistance of the coating film prepared by using the high solid epoxy coating prepared by the embodiments 1-6 and the comparative examples 1-3 of the present application are all significantly improved compared with the comparative examples 1-3.

[0080] As can be seen from the data in Table 2 and Table 3, compared with the comparative example 1, the addition of the boron nitride / PA-MA / EDA hybrid material in the embodiment 1 plays a role of physical barrier and chemical passivation, the salt spray resistance is significantly improved, the improvement of adhesion also plays a synergistic effect on the corrosion resistance, and the corrosion resistance is also obviously improved; compared with the comparative example 3, the addition of the OMWCNT-Ce-sodium gluconate composite material in the embodiment 1 plays a certain antioxidant effect, reduces the yellowing, and the yellowing resistance is significantly improved, the cerium ion and sodium gluconate also have a good corrosion inhibition effect, the salt spray resistance and the acid and alkali corrosion resistance are significantly improved, and the Figure 1 The column chart of gloss of the coating film before and after the artificial accelerated ultraviolet aging test is shown in Table 4, and it can be seen that the gloss of the coating film prepared by using the high solid epoxy coating prepared by the embodiments 1-6 and the comparative examples 1-3 of the present application still remains in a good state after the artificial accelerated ultraviolet aging test, while the gloss of the comparative examples 1 and 3 significantly decreases.

[0081] In summary, the high solid epoxy coating prepared by the embodiments 1-6 of the present application not only realizes high solid content and low VOC content, but also has good flexibility and impact resistance, good adhesion on the substrate, and good corrosion resistance and weather resistance.

[0082] The above is the preferred embodiment of the present application, and those skilled in the art can make some improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for preparing a high-solids epoxy coating, characterized in that, Includes the following steps: S1. Functionalized boron nitride is dispersed in water, ultrasonically treated, phytic acid is added and stirred, then heated, melamine and hexamethylenediamine are added and stirred, the precipitate is collected by centrifugation and vacuum dried to obtain boron nitride / PA-MA / EDA hybrid material. S2. Oxidized multi-walled carbon nanotubes were added to water and ultrasonically treated. Cerium nitrate hexahydrate and sodium gluconate were added, mixed and stirred, centrifuged to collect the precipitate, and washed to obtain the OMWCNT-Ce-sodium gluconate composite material. S3. Add solid epoxy resin, reactive diluent, and mixed solvent to a reaction vessel, heat and stir, then add liquid epoxy resin, boron nitride / PA-MA / EDA hybrid material, OMWCNT-Ce-sodium gluconate composite material, and polycaprolactone, mix and stir, grind and disperse, add curing agent and stir evenly to obtain a high-solids epoxy coating.

2. The method for preparing a high-solids epoxy coating according to claim 1, characterized in that, The functionalized boron nitride was obtained by adding 3-aminopropyltriethoxysilane and hydroxylated boron nitride to a 90% (v / v) aqueous solution of ethanol and stirring at 75-85°C for 10-12 h.

3. The method for preparing a high-solids epoxy coating according to claim 2, characterized in that, The hydroxylated boron nitride was obtained by adding boron nitride nanosheets to a 5 mol / L NaOH solution, stirring and refluxing at 50-60°C for 2 hours, filtering, washing with deionized water 3-5 times, and vacuum drying at 60-80°C for 12-24 hours.

4. The method for preparing a high-solids epoxy coating according to claim 1, characterized in that, In step S1, functionalized boron nitride is dispersed in deionized water, ultrasonically treated for 5-10 minutes, phytic acid is added and stirred for 5-10 minutes, the temperature is adjusted to 65°C, melamine and hexamethylenediamine are added and stirred for 2-3 hours, the precipitate is collected by centrifugation, and vacuum dried at 60-70°C for 12-24 hours to obtain boron nitride / PA-MA / EDA hybrid material.

5. The method for preparing a high-solids epoxy coating according to claim 1, characterized in that, In step S2, oxidized multi-walled carbon nanotubes are added to water and ultrasonically treated for 2-5 minutes. Then, cerium nitrate hexahydrate is added and the mixture is stirred under ultrasonic treatment for 3-5 hours. The mixture is centrifuged at 3000 rpm for 10 minutes, the supernatant is discarded, and the precipitate is washed with deionized water 3-5 times to obtain OMWCNT-Ce. OMWCNT-Ce is added to water and ultrasonically treated for 2-5 minutes. Then, sodium gluconate is added and the mixture is stirred under ultrasonic treatment for 2-3 hours. The mixture is centrifuged at 1200 rpm for 5 minutes, the supernatant is discarded, and the precipitate is washed with deionized water 3-5 times to obtain the OMWCNT-Ce-sodium gluconate composite material.

6. The method for preparing a high-solids epoxy coating according to claim 1, characterized in that, The oxidized multi-walled carbon nanotubes were obtained by adding multi-walled carbon nanotubes to a mixed solution containing sulfuric acid and nitric acid, stirring, heating to 100°C under reflux for 24 hours, adding deionized water, placing the solution in an ice bath, stirring for 40 minutes, letting it stand for 3 days, centrifuging at 4000 rpm for 10 minutes, discarding the supernatant and taking the precipitate, and washing it 5 times with deionized water.

7. The method for preparing a high-solids epoxy coating according to claim 1, characterized in that, The solid epoxy resin is hydrogenated bisphenol A type epoxy resin, and the liquid epoxy resin is bisphenol A type epoxy resin; the reactive diluent is one of allyl glycidyl ether, butyl glycidyl ether, and castor oil polyglycidyl ether; the mixed solvent is propylene glycol methyl ether and butanol; and the curing agent is methyltetrahydrophthalic anhydride and isophorone diamine.

8. The method for preparing a high-solids epoxy coating according to claim 1, characterized in that, In step S3, when adding liquid epoxy resin, boron nitride / PA-MA / EDA hybrid material, OMWCNT-Ce-sodium gluconate composite material, and polycaprolactone and mixing, wetting and dispersing agents, pigments and fillers, and barium sulfate are also added. When adding curing agent and mixing evenly, leveling agents and defoamers are also added.

9. The method for preparing a high-solids epoxy coating according to claim 1, characterized in that, In step S3, hydrogenated bisphenol A epoxy resin, reactive diluent, propylene glycol methyl ether, and butanol are added to a reaction vessel, heated to 50°C, and stirred at a high speed of 1200 r / min for 3-5 min. Bisphenol A epoxy resin is then added and stirred at a medium speed of 800-1000 r / min for 10-15 min. Boron nitride / PA-MA / EDA hybrid material, OMWCNT-Ce-sodium gluconate composite material, polycaprolactone, wetting and dispersing agent, pigments and fillers, and barium sulfate are added and stirred at a low speed of 300 r / min for 10 min. Then, the speed is gradually increased to 1500-2000 r / min and stirred at a high speed for 30-45 min. The temperature is lowered to 30°C, and the mixture is ground and dispersed three times. Methyltetrahydrophthalic anhydride and isophorone diamine are added and mixed and stirred at 500 rpm for 20-30 min. Leveling agent and defoamer are added and stirred at a low speed of 300 r / min for 10-20 min to obtain a high-solids epoxy coating.

10. A high-solids epoxy coating, characterized in that, The high-solids epoxy coating is prepared by the method according to any one of claims 1 to 9, comprising the following raw materials in parts by weight: 40-55 parts of solid epoxy resin, 8-16 parts of reactive diluent, 10-15 parts of mixed solvent, 15-30 parts of liquid epoxy resin, 15-20 parts of boron nitride / PA-MA / EDA hybrid material, 3-5 parts of OMWCNT-Ce-sodium gluconate composite material, 5-15 parts of polycaprolactone, and 35-50 parts of curing agent; The mixed solvent comprises the following raw materials in parts by weight: 7-10 parts of propylene glycol methyl ether and 3-5 parts of butanol; the curing agent comprises the following raw materials in parts by weight: 15-20 parts of methyltetrahydrophthalic anhydride and 20-30 parts of isophorone diamine.

Images