Efficient sewage-resistant waterborne epoxy coating and preparation method thereof

Abstract

The invention discloses an efficient sewage-resistant waterborne epoxy coating and a preparation method thereof, and relates to the technical field of coatings. Comprising the following raw materials in parts by mass: 40 to 48 parts of epoxy prepolymer, 30 to 36 parts of epoxy composite emulsion, 2 to 2.4 parts of surfactant, 5 to 7 parts of filler, 20 to 24 parts of modified silicon dioxide, 1 to 1.2 parts of dilauryl dithiodipropionate, 90 to 100 parts of deionized water, 0.5 to 0.6 part of xanthan gum and 0.4 to 0.5 part of sodium benzoate. The introduction of the epoxy prepolymer prepared from bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether and other components can effectively improve the anti-fouling ability and anti-fouling durability of the anti-fouling waterborne epoxy coating; and due to the introduction of the filler, the modified silicon dioxide and other components, the anti-pollution capability, the anti-pollution durability and the corrosion resistance of the coating are further improved. Therefore, the silicate coating disclosed by the invention has a wider application prospect.

Description

TECHNICAL FIELD

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

[0002] The waterborne epoxy paint is an environmentally friendly paint with water as the main dispersion medium, waterborne epoxy resin and supporting curing agent as the film-forming material, which has excellent adhesion, chemical resistance and mechanical properties of epoxy resin, and avoids the pollution problem of high volatile organic compounds of solvent-based paint, and is an important direction of green transformation of the current paint industry.

[0003] Based on the above characteristics, the waterborne epoxy paint is widely used in metal corrosion protection, concrete surface protection, decorative wall surface, wooden furniture protection and other fields. However, the problems of limited anti-fouling ability and durability, poor storage stability and the like limit the further expansion of the application range. SUMMARY

[0004] The purpose of the present application is to provide a high-efficiency water-resistant epoxy paint and a preparation method thereof, which solves the following technical problems:

[0005] The existing waterborne epoxy paint still has the problems of limited anti-fouling ability and durability, poor storage stability and the like.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] A high-efficiency water-resistant epoxy paint comprises the following raw materials by mass: epoxy prepolymer 40-48 parts, epoxy composite emulsion 30-36 parts, surfactant 2-2.4 parts, filler 5-7 parts, modified silicon dioxide 20-24 parts, dilauryl dithiodipropionate 1-1.2 parts, deionized water 90-100 parts, xanthan gum 0.5-0.6 parts, and sodium benzoate 0.4-0.5 parts.

[0008] Preferably, the preparation method of the epoxy prepolymer is as follows:

[0009] Step A1: 1,3-diamino-2-hydroxypropane is added to 1,3-diaminopropane and stirred for 5-6 min to obtain a curing agent;

[0010] Step A2: polyethylene glycol diglycidyl ether is added to bisphenol A diglycidyl ether and stirred at 53-57 DEG C for 10-15 min, then acetone is added and stirred for 5-6 min, and then the temperature is lowered to 48-52 DEG C, and then the curing agent is added dropwise under nitrogen atmosphere, and after the dropwise addition is completed, the temperature is raised to 68-72 DEG C and stirred for 25-30 min, and then the temperature is lowered to 39-41 DEG C and deaeration treatment is performed to obtain an epoxy prepolymer.

[0011] Preferably, the amount of 1,3-diaminopropane, 1,3-diamino-2-hydroxypropane in step A1 is 6.1-7.3g:4.1-4.9g;

[0012] The amount of bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether, acetone, curing agent in step A2 is 70-84g:30-36g:10-15g:10-12g;

[0013] The pressure in the defoaming process in step A2 is-0.1--0.09MPa, and the time is 15-20min.

[0014] Preferably, the preparation method of the epoxy composite emulsion is as follows:

[0015] Step B1: In deionized water, add itaconic acid, glycine, stir for 10-20min, then adjust pH to 7.5-8.0 with sodium carbonate solution, heat to 83-87℃ and reflux for 4-4.2h, then distill under reduced pressure to 40-50mL, then add anhydrous ethanol and azeotropically dehydrate, cool to 24-28℃, then filter, wash, vacuum dry to obtain 1-carboxymethyl pyrrolidone carboxylic acid;

[0016] Step B2: Dissolve dibutyltin dilaurate in xylene to obtain a catalyst;

[0017] Step B3: Add ethylene glycol glycidyl ether to E51 epoxy resin, heat to 58-62℃ and dissolve for 15-20min, then add 1-carboxymethyl pyrrolidone carboxylic acid and stir for 25-30min, then drop in the catalyst and react at 58-62℃ for 2-2.2h, then add nano titanium dioxide and ultrasonic dispersion to obtain an epoxy composite emulsion.

[0018] Preferably, the amount of deionized water, itaconic acid, glycine, anhydrous ethanol in step B1 is 150-180mL:146-175.2g:89-106.8g:100-120mL;

[0019] The temperature during the distillation under reduced pressure in step B1 is 59-61℃, and the pressure is-0.1--0.08MPa;

[0020] The temperature during the vacuum drying in step B1 is 48-51℃, the pressure is-0.1--0.09MPa, and the time is 10-12h;

[0021] The amount of dibutyltin dilaurate, xylene in step B2 is 0.5-0.6g:5-6mL;

[0022] The amount ratio of E51 epoxy resin, ethylene glycol glycidyl ether, 1-carboxymethyl pyrrolidone carboxylic acid, catalyst, nano titanium dioxide in step B3 is 100-120 g:20-24 g:15-18 g:5-6 mL:8-9.6 g;

[0023] The power in the ultrasonic dispersion in step B3 is 380-400 W, the frequency is 18-20 kHz, and the time length is 30-35 min.

[0024] Preferably, the surfactant is surfactant FC-4430 and surfactant BYK-349 in a mass ratio of 1:1.

[0025] Preferably, the preparation method of the filler is as follows:

[0026] Step C1: add montmorillonite to a sodium chloride solution and stir at 58-62°C for 3-4 h, wash the precipitate with deionized water after centrifugal separation, and finally dry, grind, and sieve to obtain pretreated montmorillonite;

[0027] Step C2: add cetyltrimethylammonium bromide to deionized water and stir at 78-82°C for 25-30 min, then add the pretreated montmorillonite and stir at 78-82°C for 10-12 h, and then add ethanol and benzimidazole and heat to 58-62°C to reflux for 18-20 h, and after vacuum filtration, wash, vacuum dry, grind, and sieve to obtain modified montmorillonite;

[0028] Step C3: add graphene oxide, modified montmorillonite, silane coupling agent KH-550, and silane coupling agent KH-560 to anhydrous ethanol, then ultrasonically treat at 58-62°C, and finally dry, grind, and sieve to obtain the filler.

[0029] Preferably, the amount ratio of the sodium chloride solution and montmorillonite in step C1 is 100-120 mL:10-12 g;

[0030] The mass fraction of the sodium chloride solution in step C1 is 10%;

[0031] The amount ratio of deionized water, cetyltrimethylammonium bromide, pretreated montmorillonite, ethanol, and benzimidazole in step C2 is 40-48 mL:4-4.8 g:10-12 g:20-24 mL:4-4.8 g;

[0032] The amount ratio of anhydrous ethanol, graphene oxide, modified montmorillonite, silane coupling agent KH-550, and silane coupling agent KH-560 in step C3 is 20-30 mL:1-2 g:4-6 g:2-4 g:0.06-0.1 g.

[0033] Preferably, the preparation method of the modified silica is as follows:

[0034] Step D1: after adding acetic acid and tridecafluorooctyltrimethoxysilane in deionized water, stirring for 50-60 min, a hydrolysis solution is obtained;

[0035] Step D2: adding nano-silica in toluene and ultrasonic dispersion, then adding the hydrolysis solution dropwise and heating to 78-82 DEG C, stirring for 5-6 h at 78-82 DEG C, centrifugal separation, washing the precipitate with toluene for 2-4 times, vacuum drying, grinding and sieving, to obtain the modified silica;

[0036] The amount ratio of the deionized water, acetic acid and tridecafluorooctyltrimethoxysilane in step D1 is 5 mL:0.25 mL:1.5-2.5 mL;

[0037] The amount ratio of the toluene, nano-silica and hydrolysis solution in step D2 is 150 mL:23-25 g:6.75-7.75 mL.

[0038] A preparation method of a high-efficiency water-resistant epoxy coating, comprising the following steps:

[0039] Mixing the epoxy prepolymer and the epoxy composite emulsion, stirring at 48-52 DEG C for 30-40 min, then adding the surfactant and ultrasonic dispersion, adding the filler, the modified silica and dilauryl disulfide in sequence and stirring for 1-1.2 h, adjusting the pH to 8.1-8.5, then adding deionized water, xanthan gum and sodium benzoate and stirring uniformly, finally filtering and ultrasonic defoaming to obtain the high-efficiency water-resistant epoxy coating;

[0040] The filter membrane in the filtering is a 0.22 mu m microporous filter membrane;

[0041] The pressure in the ultrasonic defoaming is-0.1--0.08 MPa, the temperature is 38-42 DEG C, the frequency is 38-40 kHz, and the time length is 30-40 min.

[0042] As a further scheme of the present application.

[0043] The present application has the following advantages:

[0044] The present application provides a high-efficiency water-resistant epoxy coating and a preparation method thereof, which effectively improves the stain resistance, stain resistance durability and storage stability of the water-based epoxy coating.

[0045] (1) The 1,3-diaminopropane in the epoxy prepolymer of the present invention reacts with the epoxy group to form a rigid cross-linked structure, thereby increasing the hardness and cross-linking density of the coating, and enhancing the mechanical strength and chemical corrosion resistance; the 1,3-diamino-2-hydroxypropane reacts with the epoxy group to add additional cross-linking points, and at the same time improves the interfacial compatibility between the resin and the polar filler, enhances the integrity of the coating, and ensures the cross-linking density. At the same time, the moderate polarity of the curing agent makes the coating surface hydrophilic, promotes the spreading of water on the coating surface, and reduces the adhesion of pollutants; the polar group also forms hydrogen bonds or chemical adsorption with modified montmorillonite and modified silica, enhancing the dispersion of the filler in the resin and improving the uniformity and density of the coating. The polyethylene glycol flexible chain segment introduced by polyethylene glycol diglycidyl ether can reduce the glass transition temperature of the resin, and its hydrophilic chain segment can form a weak hydrophilic microenvironment on the coating surface, reducing the adsorption of hydrophobic pollutants and helping to improve the anti-fouling properties. Slowly adding the curing agent under a nitrogen atmosphere and controlling the reaction temperature creates a uniform cross-linked structure and a denser coating, preventing water and contaminant penetration and improving water resistance and anti-fouling durability. When the epoxy prepolymer is subsequently mixed with the epoxy composite emulsion, the flexible segments and polar groups in the prepolymer improve the emulsion's stability, promoting uniform dispersion of the two phases, preventing phase separation, and enhancing the overall continuity of the coating.

[0046] (2) The 1-carboxymethylpyrrolidone carboxylic acid in the epoxy composite emulsion of the present invention undergoes an esterification cross-linking reaction with the epoxy resin to form a three-dimensional network structure, thereby improving the wear resistance, chemical corrosion resistance, and water resistance of the coating. The nano-titanium dioxide in the epoxy composite emulsion produces a photocatalytic effect under ultraviolet light, decomposing organic pollutants adsorbed on the surface and improving the self-cleaning ability; the nanoparticles are evenly distributed in the coating to form a microscopic rough structure, reducing the adhesion of pollutants; the shielding effect of titanium dioxide on ultraviolet rays can also inhibit the aging of the coating and improve the anti-fouling durability. The introduction of polar groups such as pyrrolidone groups in the epoxy composite emulsion can make the surface energy of the coating moderate, reduce the adhesion of oil / water pollutants, and at the same time cooperate with the hydrophobic modification components such as tridecafluorooctyltrimethoxysilane added in the subsequent step to form a "amphiphilic balance" surface, thereby optimizing the anti-fouling ability. In addition, polar groups such as carboxyl and pyrrolidone in the epoxy composite emulsion can be combined with modified montmorillonite and modified silica through hydrogen bonds or ionic bonds, thereby enhancing the interfacial compatibility between the filler and the resin matrix and improving the overall mechanical strength and impermeability; the epoxy composite emulsion will also react with the curing agent prepared by the present invention to form a double cross-link, further densifying the coating structure and enhancing water resistance and anti-fouling properties.

[0047] (3) The modified montmorillonite in the filler can enhance the hardness and tensile strength of the coating through "physical crosslinking", and form a "rigid-flexible" complementary structure with graphene oxide in the coating to form a "labyrinth effect", thereby improving the impact resistance and wear resistance of the coating, while significantly prolonging the penetration path of water, ions and pollutant molecules, reducing the permeability, and enhancing the water resistance and anti-permeation ability of the coating. The aromatic ring structure introduced by benzimidazole during the preparation of the filler can further densify the coating structure and improve the chemical stability. The modified montmorillonite can also reduce the surface energy of the coating together with the hydrophobic group of the silane coupling agent, reduce the adsorption of polar pollutants, and thus improve the stain resistance; at the same time, the two-dimensional planar structure of graphene oxide can reduce the surface roughness of the coating, and cooperate with subsequent modification to produce a "multi-level barrier + high-strength skeleton" composite effect with the modified montmorillonite, thereby synergistically reducing the surface adsorption capacity.

[0048] (4) During the preparation of the modified silica, the surface of the silica is wrapped with fluorine groups, which significantly reduces the surface energy of the coating, reduces the adsorption of pollutants such as water, oil stains and dust, and thus directly improves the stain resistance of the coating. During the modification process, the fluorocarbon chain can work together with the silicon-oxygen bond formed after the hydrolysis of silane to change the surface of the modified silica from hydrophilic to hydrophobic, thereby further strengthening the anti-pollution water permeation ability. The high bond energy and strong chemical stability of the fluorocarbon bond can also resist the erosion of acid, alkali, solvent and ultraviolet light, delay the aging of the coating, and prolong the stain resistance durability. The uniform dispersion and low surface energy characteristics of the modified silica, combined with ultrasonic treatment, can also reduce the micropores and defects in the coating, form a more dense crosslinked network, hinder the penetration of ions and microorganisms in sewage, and improve the chemical corrosion resistance and anti-bioadhesion ability. The modified silica also cooperates with fillers such as montmorillonite and graphene oxide to form a "physical barrier + chemical repulsion" dual stain resistance mechanism; and cooperates with the bridging effect of the silane coupling agent to avoid phase separation and enhance the stain resistance of the overall coating.

[0049] (5) The FC-4430 in the surfactant has extremely low surface tension, which can improve the wettability of the coating on the substrate, improve the leveling property, and enhance the chemical resistance and stain resistance of the coating; the BYK-349 can not only reduce the surface tension, defoaming and improve the compatibility, but also can reduce the pores, improve the flatness of the coating, and enhance the interfacial bonding force between the filler and the resin matrix; after the present application and the combination of the two, the BYK-349 can make up for the deficiency of FC-4430 in defoaming and compatibility, can avoid the "stable foam" problem caused by single fluorocarbon surfactant, and can also improve the leveling uniformity of the coating, improve the dispersity of the filler in the coating, make the coating structure more dense, and make it difficult for ions in sewage to penetrate, thereby significantly improving the stain resistance and durability of the coating.

[0050] Therefore, the prepared water-based epoxy coating has excellent anti-fouling ability, anti-fouling durability, corrosion resistance and storage stability, and has a more extensive application prospect. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0052] Unless otherwise specified, the following examples and comparative examples of the present application use the following information of some raw materials:

[0053] Bisphenol A diglycidyl ether was purchased from Hubei Jusheng Technology Co., Ltd., and the product code was JS0070; polyethylene glycol diglycidyl ether was purchased from Jiangsu Congzhong Chemical Co., Ltd., and the product code was 15553; E51 epoxy resin was purchased from Wuhan Jushun Chemical Co., Ltd., and the product code was js2024121009; ethylene glycol glycidyl ether was purchased from Shanghai Yuan Ye Biological Technology Co., Ltd., and the product code was S63441-500g; nano titanium dioxide (particle size: 25 nm) was purchased from Shanghai Gadel Chemical Technology Co., Ltd., and the CAS was 13463-67-7; montmorillonite (specific surface area: 240 m2 / g) was purchased from Shanghai Yuan Ye Biological Technology Co., Ltd., and the product code was S42017-500g; benzimidazole was purchased from Shanghai Guyan Industry Co., Ltd., and the CAS was 51-17-2; graphene oxide was purchased from Shanghai Xiaohua Nanometer Technology Co., Ltd., and the product code was XH-C-2; nano silicon dioxide (average particle size: 50 nm) was purchased from Shanghai Xiaohua Nanometer Technology Co., Ltd., and the product code was XH-SiO2-50.

[0054] Example 1: A preparation method of a high-efficiency anti-fouling water-based epoxy coating is as follows:

[0055] S1: 4.1g of 1,3-diamino-2-hydroxypropane was added to 6.1g of 1,3-diaminopropane and stirred at 280r / min for 5min to obtain a curing agent;

[0056] S2: 30g of polyethylene glycol diglycidyl ether was added to 70g of bisphenol A diglycidyl ether and stirred at 200r / min for 10min at 53℃, then 10g of acetone was added and stirred at 53℃ for 5min, after being reduced to 48℃, 10g of the curing agent was added dropwise at 1g / min under nitrogen atmosphere, after the dropwise addition was completed, the temperature was increased to 68℃ and stirred at 200r / min for 25min, after being reduced to 39℃, it was defoamed at -0.1MPa for 15min to obtain an epoxy prepolymer;

[0057] S3: 146 g of itaconic acid and 89 g of glycine were added into 150 mL of deionized water, stirred at 200 r / min for 10 min, and then the pH was adjusted to 7.5 with a 34.6% sodium carbonate solution. The solution was heated to 83°C and refluxed for 4 h, and then distilled under reduced pressure at 59°C and -0.1 MPa to 40 mL. Then 100 mL of anhydrous ethanol was added and the solution was azeotropically dehydrated twice. After cooling to 24°C, the solution was filtered and the filter cake was washed twice with ethanol. Finally, the filter cake was vacuum dried at 48°C and -0.1 MPa for 10 h to obtain 1-carboxymethyl pyrrolidone carboxylic acid;

[0058] S4: 0.5 g of dibutyltin dilaurate was dissolved in 5 mL of xylene to obtain a catalyst;

[0059] S5: 20 g of ethylene glycol glycidyl ether was added into 100 g of E51 epoxy resin, and the solution was heated to 58°C and dissolved for 15 min. Then 15 g of 1-carboxymethyl pyrrolidone carboxylic acid was added and stirred at 200 r / min for 25 min. Then 5 mL of the catalyst was added dropwise at a rate of 5 mL / min, and the solution was reacted at 58°C for 2 h. Then 8 g of nano-titanium dioxide was added and ultrasonic dispersed for 30 min at a power of 380 W and a frequency of 18 kHz to obtain an epoxy composite emulsion;

[0060] S6: 10 g of montmorillonite was added into 100 mL of a 10% sodium chloride solution, and stirred at 58°C and 380 r / min for 3 h. The solution was centrifuged at 3800 r / min for 10 min, and then washed with deionized water for 5 times. Finally, the solution was dried at 58°C for 10 h, ground, and sieved through a 100-mesh sieve to obtain pretreated montmorillonite;

[0061] S7: 4 g of cetyltrimethylammonium bromide was added into 40 mL of deionized water, and stirred at 78°C for 25 min. Then 10 g of the pretreated montmorillonite was added and stirred at 78°C and 280 r / min for 10 h. Then 20 mL of ethanol, 4 g of benzimidazole were added, and the solution was heated to 58°C and refluxed for 18 h. After vacuum filtration, the filter cake was washed twice with anhydrous ethanol. Finally, the filter cake was vacuum dried at 49°C for 10 h, ground, and sieved through a 200-mesh sieve to obtain modified montmorillonite;

[0062] S8: 1 g of graphene oxide, 4 g of modified montmorillonite, 2 g of silane coupling agent KH-550, and 0.06 g of silane coupling agent KH-560 were added into 20 mL of anhydrous ethanol. Then the solution was ultrasonically treated at 58°C for 1.8 h at a power of 400 W and a frequency of 20 kHz. Finally, the solution was dried at 78°C for 3.8 h, ground, and sieved through a 150-mesh sieve to obtain a filler;

[0063] S9: 0.25 mL of acetic acid, 1.5 mL of tridecafluorooctyltrimethoxysilane were added in 5 mL of deionized water and stirred at 250 r / min for 50 min to obtain a hydrolysis solution;

[0064] S10: 23 g of nano-silica was added in 150 mL of anhydrous toluene and ultrasonic dispersed for 25 min at a power of 380 W and a frequency of 18 kHz, then 6.75 mL of the hydrolysis solution was added dropwise and heated to 78℃, stirred at 200 r / min for 5 h at 78℃, then centrifuged at 8000 r / min for 10 min, the precipitate was washed with toluene for 2 times, then vacuum dried at 50℃, -0.09 MPa for 10 h, and ground through a 200 mesh sieve to obtain modified silica;

[0065] S11: 40 g of epoxy prepolymer, 30 g of epoxy composite emulsion were mixed and stirred at 48℃, 150 r / min for 30 min, then 1 g of surfactant FC-4430, 1 g of surfactant BYK-349 were added and ultrasonic dispersed for 45 min at a power of 600 W and a frequency of 40 kHz, 5 g of filler, 20 g of modified silica, 1 g of dilauryl dithiodipropionate were added in turn and mixed at 300 r / min for 1 h, then the pH was adjusted to 8.1 with 25% ammonia water, 90 mL of deionized water, 0.5 g of xanthan gum, 0.4 g of sodium benzoate were added and stirred uniformly, finally filtered through a 0.22 μm microporous filter membrane at 0.2 MPa, and ultrasonic defoamed at -0.1 MPa, 38℃ for 30 min at a frequency of 38 kHz to obtain a high-efficiency water-resistant epoxy coating.

[0066] Example 2: A preparation method of a high-efficiency water-resistant epoxy coating is as follows:

[0067] S1: 4.5 g of 1,3-diamino-2-hydroxypropane was added in 6.7 g of 1,3-diaminopropane and stirred at 290 r / min for 5.5 min to obtain a curing agent;

[0068] S2: 33 g of polyethylene glycol diglycidyl ether was added in 77 g of bisphenol A diglycidyl ether and stirred at 55℃, 230 r / min for 13 min, then 12.5 g of acetone was added and stirred at 55℃ for 5.5 min, then 11 g of the curing agent was added dropwise at 1.5 g / min under a nitrogen atmosphere after being lowered to 50℃, then the temperature was raised to 70℃ and stirred at 230 r / min for 28 min, then defoamed at -0.09 MPa for 18 min after being lowered to 40℃ to obtain an epoxy prepolymer;

[0069] S3: 160.6 g of itaconic acid and 97.9 g of glycine were added into 165 mL of deionized water, stirred at 230 r / min for 15 min, and then the pH was adjusted to 7.8 with a 34.6% sodium carbonate solution. The solution was heated to 85°C and refluxed for 4.1 h. After that, the solution was distilled under reduced pressure at 60°C and -0.09 MPa to 45 mL. Then, 110 mL of anhydrous ethanol was added and the solution was azeotropically dehydrated twice. After the solution was cooled to 26°C, it was filtered and the filter cake was washed twice with ethanol. Finally, the filter cake was vacuum dried at 50°C and -0.09 MPa for 11 h to obtain 1-carboxymethyl pyrrolidone carboxylic acid;

[0070] S4: 0.55 g of dibutyltin dilaurate was dissolved in 5.5 mL of xylene to obtain a catalyst;

[0071] S5: 22 g of ethylene glycol glycidyl ether was added into 110 g of E51 epoxy resin, which was dissolved at 60°C for 18 min. Then, 16.5 g of 1-carboxymethyl pyrrolidone carboxylic acid was added and stirred at 230 r / min for 28 min. After that, 5.5 mL of the catalyst was added dropwise at a rate of 5.5 mL / min and reacted at 60°C for 2.1 h. Then, 8.8 g of nano-titanium dioxide was added and ultrasonic dispersed at a power of 390 W and a frequency of 19 kHz for 33 min to obtain an epoxy composite emulsion;

[0072] S6: 11 g of montmorillonite was added into 110 mL of a 10% sodium chloride solution and stirred at 60°C and 390 r / min for 3.5 h. After that, the solution was centrifuged at 3900 r / min for 13 min and washed with deionized water for 6 times. Finally, the solution was dried at 60°C for 11 h, ground, and sieved through a 100-mesh sieve to obtain pretreated montmorillonite;

[0073] S7: 4.4 g of cetyltrimethylammonium bromide was added into 44 mL of deionized water and stirred at 80°C for 28 min. Then, 11 g of the pretreated montmorillonite was added and stirred at 80°C and 290 r / min for 11 h. After that, 22 mL of ethanol, 4.4 g of benzimidazole were added, and the solution was heated to 60°C and refluxed for 19 h. After vacuum filtration, the filter cake was washed with anhydrous ethanol for 3 times. Finally, the filter cake was vacuum dried at 50°C for 11 h, ground, and sieved through a 200-mesh sieve to obtain modified montmorillonite;

[0074] S8: 1.5 g of graphene oxide, 5 g of the modified montmorillonite, 3 g of silane coupling agent KH-550, and 0.08 g of silane coupling agent KH-560 were added into 25 mL of anhydrous ethanol. After that, the solution was ultrasonically treated at 60°C for 1.9 h at a power of 410 W and a frequency of 21 kHz. Finally, the solution was dried at 80°C for 3.9 h, ground, and sieved through a 150-mesh sieve to obtain a filler;

[0075] S9: 0.25 mL acetic acid, 2 mL tridecafluorooctyltrimethoxysilane were added into 5 mL deionized water, and stirred at 280 r / min for 55 min to obtain a hydrolysis solution;

[0076] S10: 24 g nano-silica was added into 150 mL anhydrous toluene, and ultrasonic dispersion was carried out at a power of 390 W and a frequency of 19 kHz for 28 min. Then 7.25 mL of the hydrolysis solution was added dropwise, and the temperature was raised to 80°C. After stirring at 210 r / min for 5.5 h at 80°C, centrifugal separation was carried out at 8000 r / min for 10 min. The precipitate was washed with toluene for 3 times, and vacuum dried at 50°C and -0.09 MPa for 11 h. After being ground through a 200 mesh sieve, modified silica was obtained;

[0077] S11: 44 g of epoxy prepolymer and 33 g of epoxy composite emulsion were mixed, and stirred at 150 r / min for 35 min at 50°C. Then 1.1 g of surfactant FC-4430 and 1.1 g of surfactant BYK-349 were added, and ultrasonic dispersion was carried out at a power of 600 W and a frequency of 40 kHz for 45 min. Then 6 g of filler, 22 g of modified silica, and 1.1 g of dilauryl dithiodipropionate were added in sequence, and mixed at 300 r / min for 1.1 h. After adjusting the pH to 8.3 with 25% ammonia water, 95 mL of deionized water, 0.55 g of xanthan gum, and 0.45 g of sodium benzoate were added and stirred uniformly. Finally, filtration was carried out through a 0.22 μm microporous filter membrane at 0.2 MPa. After ultrasonic defoaming at a frequency of 39 kHz for 35 min at -0.09 MPa and 40°C, a high-efficiency water-resistant epoxy coating was obtained.

[0078] Example 3: A preparation method of a high-efficiency water-resistant epoxy coating was as follows:

[0079] S1: 4.9 g of 1,3-diamino-2-hydroxypropane was added into 7.3 g of 1,3-diaminopropane, and stirred at 300 r / min for 6 min to obtain a curing agent;

[0080] S2: 36 g of polyethylene glycol diglycidyl ether was added into 84 g of bisphenol A diglycidyl ether, and stirred at 250 r / min for 15 min at 57°C. Then 15 g of acetone was added, and stirred at 57°C for 6 min. After being lowered to 52°C, 12 g of the curing agent was added dropwise at 2 g / min under a nitrogen atmosphere. After the dropwise addition was completed, the temperature was raised to 72°C, and stirred at 250 r / min for 30 min. After being lowered to 41°C, defoaming was carried out at -0.09 MPa for 20 min to obtain an epoxy prepolymer;

[0081] S3: 175.2 g of itaconic acid and 106.8 g of glycine were added into 180 mL of deionized water, stirred at 250 r / min for 20 min, and then the pH was adjusted to 8.0 with a 34.6% sodium carbonate solution. The mixture was heated to 87°C and refluxed for 4.2 h, and then distilled under reduced pressure at 61°C and -0.08 MPa to 50 mL. After that, 120 mL of anhydrous ethanol was added and subjected to azeotropic dehydration twice. After cooling to 28°C, the mixture was filtered and the filter cake was washed with ethanol three times. Finally, the mixture was vacuum dried at 51°C and -0.09 MPa for 12 h to obtain 1-carboxymethyl pyrrolidone carboxylic acid;

[0082] S4: 0.6 g of dibutyltin dilaurate was dissolved in 6 mL of dimethylbenzene to obtain a catalyst;

[0083] S5: 24 g of ethylene glycol glycidyl ether was added into 120 g of E51 epoxy resin, and then the mixture was heated to 62°C and dissolved for 20 min. After that, 18 g of 1-carboxymethyl pyrrolidone carboxylic acid was added and stirred at 250 r / min for 30 min. Then, 6 mL of the catalyst was added dropwise at a rate of 6 mL / min, and the mixture was reacted at 62°C for 2.2 h. After that, 9.6 g of nano-titanium dioxide was added and subjected to ultrasonic dispersion at a power of 400 W and a frequency of 20 kHz for 35 min to obtain an epoxy composite emulsion;

[0084] S6: 12 g of montmorillonite was added into 120 mL of a 10% sodium chloride solution, and then the mixture was stirred at 62°C and 400 r / min for 4 h. After that, the mixture was centrifuged at 4000 r / min for 15 min, washed with deionized water for 7 times, and finally dried at 62°C for 12 h, ground, and sieved through a 100-mesh sieve to obtain pretreated montmorillonite;

[0085] S7: 4.8 g of cetyltrimethylammonium bromide was added into 48 mL of deionized water, and then the mixture was stirred at 82°C for 30 min. After that, 12 g of the pretreated montmorillonite was added and stirred at 82°C and 300 r / min for 12 h. Then, 24 mL of ethanol and 4.8 g of benzimidazole were added, and the mixture was heated to 62°C and refluxed for 20 h. After vacuum filtration, the filter cake was washed with anhydrous ethanol for 3 times. Finally, the mixture was vacuum dried at 51°C for 12 h, ground, and sieved through a 200-mesh sieve to obtain modified montmorillonite;

[0086] S8: 2 g of graphene oxide, 6 g of the modified montmorillonite, 4 g of silane coupling agent KH-550, and 0.1 g of silane coupling agent KH-560 were added into 30 mL of anhydrous ethanol. After that, the mixture was subjected to ultrasonic treatment at 62°C for 2 h at a power of 420 W and a frequency of 22 kHz. Finally, the mixture was dried at 82°C for 4 h, ground, and sieved through a 150-mesh sieve to obtain a filler;

[0087] S9: 0.25 mL acetic acid, 2.5 mL tridecafluorooctyltrimethoxysilane were added into 5 mL deionized water, and stirred at 300 r / min for 60 min to obtain a hydrolysis solution;

[0088] S10: 25 g nano-silica was added into 150 mL anhydrous toluene, and ultrasonic dispersion was performed at a power of 400 W and a frequency of 20 kHz for 30 min. Then 7.75 mL of the hydrolysis solution was added dropwise, and the temperature was raised to 82°C. After stirring at 220 r / min for 6 h at 82°C, centrifugal separation was performed at 8000 r / min for 10 min. The precipitate was washed with toluene for 4 times, and vacuum drying was performed at 50°C and -0.09 MPa for 12 h. The product was ground through a 200 mesh sieve to obtain modified silica;

[0089] S11: 48 g epoxy prepolymer, 36 g epoxy composite emulsion were mixed, and stirred at 52°C and 150 r / min for 40 min. Then 1.2 g surfactant FC-4430, 1.2 g surfactant BYK-349 were added, and ultrasonic dispersion was performed at a power of 600 W and a frequency of 40 kHz for 45 min. Then 7 g filler, 24 g modified silica, 1.2 g dilauryl dithiodipropionate were added in sequence, and mixed at 300 r / min for 1.2 h. After adjusting the pH to 8.5 by using 25% ammonia water, 100 mL deionized water, 0.6 g xanthan gum, and 0.5 g sodium benzoate were added, and stirred uniformly. Finally, high-efficiency water-repellent epoxy coating was obtained by filtering through a 0.22 μm microporous filter membrane at 0.2 MPa, and ultrasonic defoaming was performed at -0.08 MPa, 42°C, and a frequency of 40 kHz for 40 min.

[0090] Comparative Example 1:

[0091] In this comparative example, only the “40 g epoxy prepolymer” added in the preparation process of the high-efficiency water-repellent epoxy coating in S11 of Example 1 was replaced by the “40 g epoxy composite emulsion” prepared in S5, and the other steps and parameters were the same. The high-efficiency water-repellent epoxy coating was obtained.

[0092] Comparative Example 2:

[0093] In this comparative example, only the “30 g epoxy composite emulsion” added in the preparation process of the high-efficiency water-repellent epoxy coating in S11 of Example 1 was replaced by “30 g E51 epoxy resin”, and the other steps and parameters were the same. The high-efficiency water-repellent epoxy coating was obtained.

[0094] Comparative Example 3:

[0095] The comparative example is compared with example 1 only replacing the "30 g epoxy complex emulsion" added in the preparation process of the high-efficiency anti-fouling water epoxy coating of S11 with "30 g epoxy prepolymer" prepared by S2, and the rest of the steps and parameters are the same. The comparative example will not be repeated here. Finally, the high-efficiency anti-fouling water epoxy coating is obtained.

[0096] Comparative example 4:

[0097] The comparative example is compared with example 1 only replacing the "modified montmorillonite" added in the preparation process of the high-efficiency anti-fouling water epoxy coating of S8 with "montmorillonite", and the rest of the steps and parameters are the same. The comparative example will not be repeated here. Finally, the high-efficiency anti-fouling water epoxy coating is obtained.

[0098] Comparative example 5:

[0099] The comparative example is compared with example 1 only replacing the "modified montmorillonite" added in the preparation process of the high-efficiency anti-fouling water epoxy coating of S8 with "graphene oxide", and the rest of the steps and parameters are the same. The comparative example will not be repeated here. Finally, the high-efficiency anti-fouling water epoxy coating is obtained.

[0100] Comparative example 6:

[0101] The comparative example is compared with example 1 only replacing the "graphene oxide" added in the preparation process of the high-efficiency anti-fouling water epoxy coating of S8 with "modified montmorillonite", and the rest of the steps and parameters are the same. The comparative example will not be repeated here. Finally, the high-efficiency anti-fouling water epoxy coating is obtained.

[0102] Comparative example 7:

[0103] The comparative example is compared with example 1 only replacing the "1 g surfactant FC-4430, 1 g surfactant BYK-349" added in the preparation process of the high-efficiency anti-fouling water epoxy coating of S11 with "2 g surfactant FC-4430", and the rest of the steps and parameters are the same. The comparative example will not be repeated here. Finally, the high-efficiency anti-fouling water epoxy coating is obtained.

[0104] Comparative example 8:

[0105] The comparative example is compared with example 1 only replacing the "20 g modified silica" added in the preparation process of the high-efficiency anti-fouling water epoxy coating of S11 with "20 g nano-silica", and the rest of the steps and parameters are the same. The comparative example will not be repeated here. Finally, the high-efficiency anti-fouling water epoxy coating is obtained.

[0106] Comparative example 9:

[0107] The comparative example is compared with example 1 only by replacing the "4.1 g of 1,3-diamino-2-hydroxypropane" added in the curing agent preparation process of S1 with "4.1 g of 1,3-diaminopropane", and the rest of the steps and parameters are the same. The comparative example will not be repeated here. Finally, the high-efficiency water-resistant epoxy coating is obtained.

[0108] Performance detection:

[0109] The surface of the aluminum plate with a size of 50 mm x 100 mm x 3 mm is uniformly coated with 1.0 mm thick high-efficiency water-resistant epoxy coating prepared by example 1- example 3 and comparative example 1- comparative example 9. Then, it is cured at 25℃ for 2h, then cross-linked at 50℃ for 4h, then dried at 80℃ for 6h, and finally treated with 365nm, 100mW / cm2 ultraviolet light for 30min to obtain the sample plate.

[0110] Determination of anti-fouling capacity (%):

[0111] According to the steps of GB / T 9276-1996 "Coating Stain Resistance Test Method", 80g fly ash (particle size ≤0.08mm), 20g light calcium carbonate, 100g water are mixed and stirred uniformly into a paste to obtain the mortar. Then the mortar is uniformly coated on the surface of the sample plate with a spatula, and after standing for 5min, the excess mortar is scraped off with a spatula. After drying at room temperature for 2h, the test plate is fixed on the scrubbing test machine, and scrubbed 100 times with 0.5% neutral detergent in 40℃ water solution at a frequency of 50 times / min. After drying, the reflectivity of the contaminated area and the non-contaminated area of the test plate is measured with a reflectivity meter (wavelength 550nm), and the reflectivity of the reference white plate is also measured. The stain rate (%) of the sample plate is calculated. The lower the stain rate, the stronger the anti-fouling ability of the coating. The anti-fouling ability of the sample prepared by the high-efficiency water-resistant epoxy coating prepared by example 1- example 3 and comparative example 1- comparative example 9 before and after being irradiated by a fluorescent ultraviolet lamp (UV-A 340 type) for 200h (25 cycles of 8h light, one cycle of 8h light is 4h irradiation at a temperature of 60℃, RH of 50%, irradiation intensity of 0.5W / m2 / nm, wavelength of 340nm, distance of 10mm + 4h temperature of 50℃, RH of 100%) is determined according to the above method. The test results are shown in table 1.

[0112] Determination of corrosion resistance (h):

[0113] Referring to the test standard of GB / T10125-2021 "Artificial Atmosphere Corrosion Test-Salt Spray Test", the sample plate was edge-sealed with epoxy putty, and then placed in a salt spray test chamber (JAY-1127, Zhuhai Jiayi Testing Equipment Co., Ltd.), and subjected to a 24-hour salt spray and 24-hour drying cycle test at 35°C, pH=6.5-7.2, and a concentration of 5% sodium chloride solution. Samples were taken and observed every 48 hours, and the test time for the appearance of red rust on each sample was recorded. The neutral salt spray test was terminated when the last sample showed red rust. The corrosion resistance of the samples made of the high-efficiency sewage-resistant epoxy coatings prepared in Examples 1-3 and Comparative Examples 1-9 of the present invention was determined according to the above method. The test results are shown in Table 1

[0114] Determination of oil contact angle (°) and water contact angle (°):

[0115] With reference to GB / T 24368-2009 "Determination of contact angle of paint and varnish films", the oil contact angle (diiodomethane) and water contact angle (deionized water) of the samples made of the high-efficiency sewage-resistant epoxy coatings prepared in Examples 1 to 3 and Comparative Examples 1 to 8 of the present invention were measured. The test results are shown in Table 1.

[0116] Determination of storage stability (h):

[0117] With reference to the determination standard of GB / T 6753.3-1986 "Test method for storage stability of coatings", 200 mL of the high-efficiency sewage-resistant epoxy coatings prepared in Examples 1 to 3 and Comparative Examples 1 to 9 of the present invention were sealed in a transparent glass container and observed every 12 hours under conditions of 50°C and 50% RH. The time when the coatings delaminated was recorded. The test results are shown in Table 1.

[0118] Table 1: Performance test results of Examples 1-3 and Comparative Examples 1-9

[0119]

[0120] Data Analysis:

[0121] As can be seen from Table 1, the high-efficiency sewage-resistant epoxy coating prepared in the embodiment of the present invention has a low staining rate and staining rate after aging and high corrosion resistance, oil contact angle, water contact angle and storage stability. That is, the present invention has excellent anti-fouling ability, anti-fouling durability, corrosion resistance and storage stability.

[0122] The above has been described in detail one embodiment of the present application, but the content is only the preferred embodiment of the present application, cannot be considered for limiting the scope of the present application. Any equivalent changes and improvements made in the scope of the present application, should still belong to the scope of the present application.

Claims

1. A high-efficiency sewage-resistant epoxy coating, characterized in that: The invention comprises the following raw materials in parts by mass: 40-48 parts of epoxy prepolymer, 30-36 parts of epoxy composite emulsion, 2-2.4 parts of surfactant, 5-7 parts of filler, 20-24 parts of modified silicon dioxide, 1-1.2 parts of dilauryl dithiodipropionate, 90-100 parts of deionized water, 0.5-0.6 parts of xanthan gum and 0.4-0.5 parts of sodium benzoate.

2. The high-efficiency sewage-resistant epoxy coating according to claim 1, wherein The preparation method of the epoxy prepolymer is as follows: Step A1: Add 1,3-diamino-2-hydroxypropane to 1,3-diaminopropane and stir for 5-6 minutes to obtain a curing agent; Step A2: Add polyethylene glycol diglycidyl ether to bisphenol A diglycidyl ether and stir at 53-57°C for 10-15 minutes. Then add acetone and stir for 5-6 minutes. After cooling to 48-52°C, add curing agent dropwise under a nitrogen atmosphere. After the addition is complete, heat to 68-72°C and stir for 25-30 minutes. After cooling to 39-41°C, degassing is performed to obtain an epoxy prepolymer.

3. The high-efficiency sewage-resistant epoxy coating according to claim 2, wherein The ratio of 1,3-diaminopropane to 1,3-diamino-2-hydroxypropane in step A1 is 6.1-7.3 g: 4.1-4.9 g; The usage ratio of bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether, acetone, and curing agent in step A2 is 70-84 g: 30-36 g: 10-15 g: 10-12 g.

4. The high-efficiency sewage-resistant epoxy coating according to claim 1, wherein The preparation method of the epoxy composite emulsion is as follows: Step B1: Add itaconic acid and glycine to deionized water, stir for 10-20 minutes, adjust the pH to 7.5-8.0 with sodium carbonate solution, heat to 83-87°C and reflux for 4-4.2 hours, then distill under reduced pressure to 40-50 mL, then add anhydrous ethanol and perform azeotropic dehydration, cool to 24-28°C, filter, wash, and vacuum dry to obtain 1-carboxymethylpyrrolidonecarboxylic acid; Step B2: dissolving dibutyltin dilaurate in xylene to obtain a catalyst; Step B3: Add ethylene glycol glycidyl ether to E51 epoxy resin, heat to 58-62°C and dissolve for 15-20 minutes, then add 1-carboxymethyl pyrrolidone carboxylic acid and stir for 25-30 minutes, then drop the catalyst and react at 58-62°C for 2-2.2 hours, then add nano-titanium dioxide and ultrasonically disperse to obtain an epoxy composite emulsion.

5. The high-efficiency sewage-resistant epoxy coating according to claim 4, wherein The ratio of deionized water, itaconic acid, glycine, and anhydrous ethanol used in step B1 is 150-180 mL: 146-175.2 g: 89-106.8 g: 100-120 mL; The ratio of dibutyltin dilaurate to xylene in step B2 is 0.5-0.6 g: 5-6 mL; The usage ratio of E51 epoxy resin, ethylene glycol glycidyl ether, 1-carboxymethyl pyrrolidone carboxylic acid, catalyst, and nano-titanium dioxide in step B3 is 100-120 g: 20-24 g: 15-18 g: 5-6 mL: 8-9.6 g.

6. The high-efficiency sewage-resistant epoxy coating according to claim 1, wherein The surfactants are surfactant FC-4430 and surfactant BYK-349 in a mass ratio of 1:

1.

7. The high-efficiency sewage-resistant epoxy coating according to claim 1, wherein The preparation method of the filler is as follows: Step C1: adding montmorillonite to a sodium chloride solution and stirring at 58-62° C. for 3-4 hours, centrifuging and washing the precipitate with deionized water, and finally drying, grinding, and sieving to obtain pretreated montmorillonite; Step C2: adding hexadecyltrimethylammonium bromide to deionized water and stirring at 78-82° C. for 25-30 minutes, then adding pretreated montmorillonite and stirring at 78-82° C. for 10-12 hours, then adding ethanol and benzimidazole and heating to 58-62° C. and reflux for 18-20 hours, vacuum filtering, washing, vacuum drying, grinding, and sieving to obtain modified montmorillonite; Step C3: adding graphene oxide, modified montmorillonite, silane coupling agent KH-550, and silane coupling agent KH-560 to anhydrous ethanol, then performing ultrasonic treatment at 58-62° C., and finally drying, grinding, and sieving to obtain a filler.

8. The high-efficiency sewage-resistant epoxy coating according to claim 7, wherein The ratio of sodium chloride solution to montmorillonite in step C1 is 100-120 mL: 10-12 g; The mass fraction of the sodium chloride solution in step C1 is 10%; In step C2, the ratio of deionized water, hexadecyltrimethylammonium bromide, pretreated montmorillonite, ethanol, and benzimidazole is 40-48 mL: 4-4.8 g: 10-12 g: 20-24 mL: 4-4.8 g; The usage ratio of anhydrous ethanol, graphene oxide, modified montmorillonite, silane coupling agent KH-550, and silane coupling agent KH-560 in step C3 is 20-30 mL: 1-2 g: 4-6 g: 2-4 g: 0.06-0.1 g.

9. The high-efficiency sewage-resistant epoxy coating according to claim 1, wherein The preparation method of the modified silicon dioxide is as follows: Step D1: Add acetic acid and tridecafluorooctyltrimethoxysilane to deionized water and stir for 50-60 minutes to obtain a hydrolyzed solution; Step D2: adding nano-silica to toluene and ultrasonically dispersing the mixture, then dropwise adding the hydrolyzate and heating the mixture to 78-82° C., stirring the mixture at 78-82° C. for 5-6 hours, and then centrifuging the mixture. The precipitate is washed 2-4 times with toluene, vacuum dried, ground, and sieved to obtain modified silica. The usage ratio of deionized water, acetic acid, and tridecafluorooctyltrimethoxysilane in step D1 is 5 mL: 0.25mL: 1.5-2.5mL; The usage ratio of toluene, nano-silica and hydrolyzed solution in step D2 is 150 mL: 23-25 ​​g: 6.75-7.75 mL.

10. A method for preparing a high-efficiency sewage-resistant epoxy coating according to any one of claims 1 to 9, characterized in that: The following steps are involved: The epoxy prepolymer and epoxy composite emulsion are mixed and stirred at 48-52°C for 30-40 minutes, then a surfactant is added and ultrasonic dispersion is performed, filler, modified silica, and dilauryl dithiodipropionate are added in sequence and stirred for 1-1.2 hours, the pH is adjusted to 8.1-8.5, and then deionized water, xanthan gum, and sodium benzoate are added and stirred evenly, and finally filtered and ultrasonically degassed to obtain a high-efficiency sewage-resistant epoxy coating.

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