Preparation method of high-wear-resistance water-based toughened epoxy resin coating

Abstract

The invention discloses a preparation method of a high-wear-resistance water-based toughened epoxy resin coating, and belongs to the technical field of anticorrosive paints.The high-wear-resistance water-based toughened epoxy resin coating is obtained by dispersing silicon dioxide lubricating nanospheres in the coating and then copolymerizing methacrylic acid modified epoxy resin and acrylic acid grafted aniline, aniline is grafted into a polymeric chain, and the high-wear-resistance water-based toughened epoxy resin coating is obtained. The crosslinking density of the modified epoxy resin is improved, the hardness and the scratch resistance are synchronously enhanced, nitrogen atoms in amino groups in aniline carry lone pair electrons and can form coordinate bonds with empty d orbits on the metal surface, so that aniline molecules are adsorbed on the metal surface to form a compact hydrophobic protection layer, and the hydrophobic property of the metal surface is improved. In the process, the contact between the corrosive medium and the metal is blocked through the physical shielding effect, so that the electrochemical corrosion reaction is inhibited.

Description

Technical Field

[0001] The invention belongs to the technical field of anti-corrosion coatings, and specifically relates to a method for preparing a highly wear-resistant water-based toughened epoxy resin coating. Background Art

[0002] Epoxy resins have long been widely used in various fields, including casting, coatings, and construction, due to their excellent mechanical properties, corrosion and chemical resistance, and good adhesion. However, after curing, epoxy resin films suffer from high crosslink density, high internal stress, brittleness, and poor toughness, which limit their application. Therefore, toughening modification of epoxy resins is necessary.

[0003] Epoxy resin toughening primarily involves modifying the already uniformly dispersed epoxy resin and adding toughening agents to enhance the toughness of the cured epoxy resin product. Well-established approaches for toughening epoxy resins both domestically and internationally include introducing dispersed phases such as rubber particles, thermoplastic resins, and nanoparticles with specific functionalities into the epoxy matrix; molecular engineering of the epoxy resin and a second component to form interpenetrating / semi-interpenetrating polymer networks; and the design of core-shell polymers and block copolymers. These methods enhance the toughness and impact resistance of the epoxy resin while simplifying the process and imparting new, unique properties to the cured product.

[0004] Chinese patent CN101633814B discloses a method for preparing a water-based epoxy resin anti-corrosion coating. This method uses aminosiloxane as a modifier for epoxy graft copolymers. Through graft copolymerization, acrylate monomers are grafted onto the epoxy resin, imparting a certain degree of hydrophilicity. Due to its excellent weathering and moisture resistance, flexibility, water resistance, and chemical resistance, as well as its ability to react with epoxy resins, aminosiloxanes can be used as ring-opening agents for epoxy resins. The self-crosslinking aminosiloxane ring-opening agent opens the epoxy groups in the epoxy resin, improving the stability of the aqueous dispersion. Because the ring-opening agent contains self-crosslinking groups, it also addresses the shortcomings of water-based epoxy resin coatings in terms of poor water and corrosion resistance, resulting in a stable water-based epoxy resin. The ether bonds in the epoxy resin molecular chain are susceptible to rupture and degradation under ultraviolet radiation, resulting in powdering and loss of gloss in the coating. While the introduction of siloxane bonds can partially improve weather resistance, the acrylate segments still pose a risk of UV aging. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a highly wear-resistant water-based toughened epoxy resin coating, which is obtained by dispersing silica lubricating nanospheres in the coating and then copolymerizing methacrylic acid-modified epoxy resin and acrylic acid-grafted aniline. The coating has excellent impact resistance, wear resistance and corrosion resistance, strong coating adhesion and is not easy to fall off, and is not easily aged or stained with oil.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A method for preparing a highly wear-resistant water-based toughened epoxy resin coating comprises the following steps: Acrylic acid grafted aniline, methacrylic acid modified epoxy resin, silica lubricating nanospheres and deionized water are added to a reactor, nitrogen is introduced for protection, and the reaction is stirred at 95-100° C. and 500-600 r / min for 1-2 hours. The reactor is cooled to 55-65° C., and an initiator, sodium persulfate, and a cross-linking agent, hydroxymethyl acrylamide, are added to the reactor. The reactor is heated to 70-80° C. and stirred at 500-600 r / min for 3-4 hours. The reactor is filtered, and the filter cake is washed 2-3 times with deionized water and anhydrous ethanol respectively, dried in a vacuum at 60-80° C. for 1-2 hours, and crushed and granulated to obtain a highly wear-resistant water-based toughened epoxy resin coating.

[0007] Furthermore, the usage ratio of acrylic acid grafted aniline, methacrylic acid modified epoxy resin, silica lubricating nanospheres, deionized water, sodium persulfate and hydroxymethyl acrylamide is 30-40g: 150-180g: 12-14g: 2-3L: 7-9g: 5-8g.

[0008] Furthermore, acrylic acid grafted aniline is prepared by the following steps: Acrylic acid grafted acetanilide and deionized water are added to a reaction kettle, followed by addition of sodium hydroxide. The mixture is stirred at 80-90° C. and 400-500 r / min for 3-4 hours, cooled naturally to room temperature, and 1 mol / L acetic acid solution is added to adjust the pH value to 6-7. The mixture is filtered, and the filter cake is washed 2-3 times with anhydrous ethanol and deionized water, and dried in vacuo at 60-80° C. for 1-2 hours to obtain acrylic acid grafted aniline.

[0009] Furthermore, the usage ratio of acrylic acid grafted acetanilide, deionized water and sodium hydroxide is 40-50 g: 200-300 mL: 4-5 g.

[0010] Furthermore, acrylic acid grafted acetanilide is prepared by the following steps: Fluorinated acetanilide, 3-aminopropyltriethoxysilane, anhydrous ethanol and deionized water are added to a reactor, stirred at 80-85°C and 400-500 r / min for 1-2 hours, and then acrylic acid solution and hydroquinone as a polymerization inhibitor are added. The reaction is continued for 1-2 hours, filtered, and the filter cake is washed with deionized water 2-3 times and vacuum dried at 60-80°C for 1-2 hours to obtain acrylic acid-grafted acetanilide.

[0011] Furthermore, the usage ratio of fluorinated acetanilide, 3-aminopropyltriethoxysilane, anhydrous ethanol, deionized water, acrylic acid solution and hydroquinone is 40-50 g: 20-30 mL: 180-200 mL: 200-300 mL: 50-60 mL: 0.5-0.8 g.

[0012] Further, fluorinated acetanilide is prepared by the following steps: Add fluorinated hydroxyaniline and deionized water into a reaction kettle, stir at 35-40°C and 400-500 r / min for 30-40 minutes, then add sodium chloride, acetic acid solution and acetic anhydride, heat to 70-80°C, continue stirring for 4-5 hours, cool naturally to room temperature, filter, and wash the filter cake with anhydrous ethanol and deionized water 2-3 times to obtain fluorinated acetanilide.

[0013] Furthermore, the usage ratio of fluorinated hydroxyaniline, deionized water, sodium chloride, acetic acid solution and acetic anhydride is 50-60 g: 200-300 mL: 30-40 g: 30-40 mL: 20-30 mL.

[0014] Furthermore, the methacrylic acid modified epoxy resin is prepared by the following steps: Add bisphenol A epoxy resin, triphenylphosphine and toluene into a reactor, stir at 100-110°C and 400-500 r / min for 40-50 minutes, then add methacrylic acid and hydroquinone as a polymerization inhibitor, continue stirring for 3-4 hours, filter, wash the filter cake with anhydrous ethanol and deionized water 2-3 times, and vacuum dry at 60-80°C for 1-2 hours to obtain a methacrylic acid modified epoxy resin.

[0015] Furthermore, the usage ratio of bisphenol A epoxy resin, triphenylphosphine, toluene, methacrylic acid and hydroquinone is 200-300 mL: 15-20 g: 2-3 L: 120-150 g: 2.5-3 g.

[0016] Furthermore, the silica lubricating nanospheres are prepared by the following steps: Polystyrene microspheres with a particle size of 20-30 nm and deionized water are added to a reactor, stirred at 20-25°C and 500-600 r / min for 30-40 minutes, then cetyltrimethylammonium bromide and tetraethyl silicate are added, stirring is continued for 4-5 hours, and a 2.0 M hydrochloric acid solution is added dropwise at a rate of 8-9 mL / min, stirring is continued for 5-6 hours, and the reaction mixture is filtered. The filter cake is washed with N,N-dimethylformamide to remove the polystyrene template, and then washed with anhydrous ethanol 2-3 times, and vacuum dried at 60-80°C for 1-2 hours to obtain silica lubricating nanospheres.

[0017] Furthermore, the usage ratio of the polystyrene microspheres, deionized water, hexadecyltrimethylammonium bromide, tetraethyl silicate and hydrochloric acid solution is 20-30 g: 800-900 mL: 4-5 g: 120-150 mL: 3-3.2 L.

[0018] Beneficial effects of the present invention: 1. The highly wear-resistant water-based toughened epoxy resin coating prepared by the present invention is obtained by dispersing silica lubricating nanospheres in the coating and then copolymerizing methacrylic acid-modified epoxy resin and acrylic acid-grafted aniline. The coating has excellent impact resistance, wear resistance and corrosion resistance, strong coating adhesion and is not easy to fall off, and is not easily aged or stained with oil.

[0019] 2. In the present invention, acrylic acid grafted aniline undergoes a nucleophilic addition reaction of fluorinated hydroxyaniline to generate acetanilide, pre-protecting the amino group. Acrylic acid is then grafted onto the acetanilide using 3-aminopropyltriethoxysilane. In a subsequent step, the double bonds of the acrylic acid grafted acetanilide and the double bonds in the methacrylic acid-modified epoxy resin are copolymerized in the presence of an initiator, thereby grafting the aniline into the polymer chain to form a denser network structure. The modified resin has an increased crosslinking density, and its hardness and scratch resistance are simultaneously enhanced. The nitrogen atom in the amino group of the aniline carries a lone pair of electrons, which can form a coordination bond with an empty d orbital on the metal surface, allowing the aniline molecules to be adsorbed on the metal surface to form a dense hydrophobic protective layer. This process blocks contact between the corrosive medium and the metal through a physical shielding effect, thereby inhibiting the electrochemical corrosion reaction.

[0020] 3. The methacrylic acid-modified epoxy resin of the present invention has a carboxyl group of methacrylic acid attacking the epoxy group to open the ring, and grafting the double bond to the epoxy resin surface, thereby copolymerizing with the subsequent acrylic acid-grafted acetanilide. The resulting acrylic acid and aniline have strong interfacial bonding with the epoxy resin, avoiding the problems of poor dispersibility and poor interfacial bonding caused by conventional direct addition. Acrylic acid can increase the crosslinking density of the epoxy resin, increase the number of active groups on the polymer surface, and improve the adhesion strength between the coating and the substrate. 4. The silica lubricating nanospheres of the present invention are prepared by covering the surface of polystyrene microspheres with silica lubricating nanospheres using polystyrene microspheres as templates, and then removing the polystyrene microspheres with N,N-dimethylformamide to obtain hollow silica lubricating nanospheres. The silica lubricating nanospheres are dispersed in an epoxy resin coating to disperse stress by slipping, thereby improving the impact strength and wear resistance of the coating. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] Example 1: A method for preparing a highly wear-resistant water-based toughened epoxy resin coating, comprising the following steps: S1: Add 50 g of fluorinated hydroxyaniline and 200 mL of deionized water into a reactor, stir at 35°C and 400 r / min for 30 min, then add 30 g of sodium chloride, 30 mL of acetic acid solution and 20 mL of acetic anhydride, heat to 70°C, continue stirring for 4 h, cool naturally to room temperature, filter, wash the filter cake twice with anhydrous ethanol and deionized water, and dry in vacuo at 60°C for 1 h to obtain fluorinated acetanilide.

[0023] The amino group in fluorinated hydroxyaniline acts as a nucleophile to attack the carbonyl carbon of acetic anhydride, causing a nucleophilic addition reaction to generate acetanilide, thus pre-protecting the amino group.

[0024] S2: 40 g of fluorinated acetanilide, 20 mL of 3-aminopropyltriethoxysilane, 180 mL of anhydrous ethanol and 200 mL of deionized water were added to a reactor, stirred at 80°C and 400 r / min for 1 h, then 50 mL of acrylic acid solution and 0.5 g of hydroquinone as a polymerization inhibitor were added, and the reaction was continued for 1 h. The mixture was filtered, and the filter cake was washed twice with deionized water and dried in vacuo at 60°C for 1 h to obtain acrylic acid-grafted acetanilide.

[0025] The hydroxyl group in the fluorinated acetanilide reacts with the silanol generated by 3-aminopropyltriethoxysilane under the action of hydrolysis to obtain acrylic acid-grafted acetanilide.

[0026] By converting fluorinated hydroxyaniline into fluorinated acetanilide, the reaction between the carboxyl group of acrylic acid and the amino group is avoided when grafting acrylic acid. The nitrogen atom of the amino group of aniline provides a lone pair of electrons, forming a coordination bond with the empty orbital on the metal surface, forming a dense adsorption film, and physically blocking the corrosive medium. If the amino group is reacted, the lone pair of electrons will be occupied, the coordination ability will be lost, and the corrosion resistance will be reduced.

[0027] S3: 40 g of acrylic acid grafted acetanilide and 200 mL of deionized water were added to a reactor, followed by the addition of 4 g of sodium hydroxide. The mixture was stirred at 80°C and 400 rpm for 3 h, and naturally cooled to room temperature. A 1 mol / L acetic acid solution was added to adjust the pH to 6, and the mixture was filtered. The filter cake was washed twice with anhydrous ethanol and deionized water, and dried in vacuo at 60°C for 1 h to obtain acrylic acid grafted aniline.

[0028] Acrylic acid grafted acetanilide is hydrolyzed under alkaline conditions to expose the protected amino group on aniline.

[0029] S4: Add 200 mL of bisphenol A epoxy resin, 15 g of triphenylphosphine and 2 L of toluene into a reactor, stir at 100°C and 400 r / min for 40 min, then add 120 g of methacrylic acid and 2.5 g of hydroquinone as a polymerization inhibitor, continue stirring for 3 h, filter, wash the filter cake twice with anhydrous ethanol and deionized water, and vacuum dry at 60°C for 1 h to obtain methacrylic acid modified epoxy resin.

[0030] Triphenylphosphine acts as a nucleophilic catalyst to attack the epoxy group of the epoxy resin, causing it to open its ring to form an oxygen anion intermediate, which further attacks the hydroxyl group of methacrylic acid to form an ester bond through a nucleophilic substitution reaction.

[0031] S5: Add 20 g of polystyrene microspheres with a particle size of 20 nm and 800 mL of deionized water into the reactor, stir at 20°C and 500 r / min for 30 min, then add 4 g of hexadecyltrimethylammonium bromide and 120 mL of tetraethyl silicate, continue stirring for 4 h, add 3 L of 2.0 M hydrochloric acid solution dropwise at a rate of 8 mL / min, continue stirring for 5 h, filter, wash the filter cake with N,N-dimethylformamide to remove the polystyrene template, then wash twice with anhydrous ethanol, and vacuum dry at 60°C for 1 h to obtain silica lubricated nanospheres.

[0032] S6: 30g of acrylic acid grafted aniline, 150g of methacrylic acid modified epoxy resin, 12g of silica lubricated nanospheres and 2L of deionized water were added to a reactor, nitrogen protection was introduced, and the reaction was stirred at 95°C and 500r / min for 1h. The reaction was cooled to 55°C, and 7g of initiator sodium persulfate and 5g of cross-linking agent hydroxymethyl acrylamide were added to the reactor. The reaction was heated to 70°C and stirred at 500r / min for 3h. The reaction was filtered, and the filter cake was washed twice with deionized water and anhydrous ethanol respectively, dried in a vacuum at 60°C for 1h, crushed and granulated to obtain a highly wear-resistant water-based toughened epoxy resin coating.

[0033] Through a grafting reaction, acrylic groups introduce crosslinking points into the epoxy resin molecular chain, forming a denser network structure. This structure effectively resists external friction and reduces surface wear. The modified resin has a higher crosslink density, while simultaneously enhancing hardness and scratch resistance. The double bonds in acrylic acid participate in the polymerization reaction, forming a more rigid polymer backbone. Aniline is grafted onto the main chain or side chains of the acrylic-modified epoxy resin, forming a stable structure connected by covalent bonds. Flexible aniline segments are introduced into the crosslinked network, improving elongation at break.

[0034] Example 2: A method for preparing a highly wear-resistant water-based toughened epoxy resin coating, comprising the following steps: S1: Add 55 g of fluorinated hydroxyaniline and 250 mL of deionized water into a reactor, stir at 38°C and 450 r / min for 35 min, then add 35 g of sodium chloride, 35 mL of acetic acid solution and 25 mL of acetic anhydride, heat to 75°C, continue stirring for 4.5 h, cool naturally to room temperature, filter, wash the filter cake twice with anhydrous ethanol and deionized water, and dry in vacuo at 70°C for 1.5 h to obtain fluorinated acetanilide.

[0035] S2: 45 g of fluorinated acetanilide, 25 mL of 3-aminopropyltriethoxysilane, 190 mL of anhydrous ethanol and 250 mL of deionized water were added to a reactor, stirred at 83°C and 450 r / min for 1.5 h, then 55 mL of acrylic acid solution and 0.65 g of hydroquinone as a polymerization inhibitor were added, and the reaction was continued for 1.5 h. The mixture was filtered, and the filter cake was washed twice with deionized water and dried in vacuo at 70°C for 1.5 h to obtain acrylic acid-grafted acetanilide.

[0036] S3: 45 g of acrylic acid grafted acetanilide and 250 mL of deionized water were added to a reactor, followed by the addition of 4.5 g of sodium hydroxide. The mixture was stirred at 85°C and 450 r / min for 3.5 h, and naturally cooled to room temperature. A 1 mol / L acetic acid solution was added to adjust the pH to 6.5, and the mixture was filtered. The filter cake was washed twice with anhydrous ethanol and deionized water, and vacuum dried at 70°C for 1.5 h to obtain acrylic acid grafted aniline.

[0037] S4: Add 250 mL of bisphenol A epoxy resin, 18 g of triphenylphosphine and 2.5 L of toluene into a reactor, stir at 105°C and 450 r / min for 45 min, then add 135 g of methacrylic acid and 2.75 g of hydroquinone as an inhibitor, continue stirring for 3.5 h, filter, wash the filter cake twice with anhydrous ethanol and deionized water, and vacuum dry at 70°C for 1.5 h to obtain methacrylic acid modified epoxy resin.

[0038] S5: Add 25 g of polystyrene microspheres with a particle size of 25 nm and 850 mL of deionized water into the reactor, stir at 23 ° C and 550 r / min for 35 min, then add 4.5 g of hexadecyltrimethylammonium bromide and 135 mL of tetraethyl silicate, continue stirring for 4.5 h, add 3.1 L of 2.0 M hydrochloric acid solution dropwise at a rate of 8.5 mL / min, continue stirring for 5.5 h, filter, wash the filter cake with N, N-dimethylformamide to remove the polystyrene template, then wash twice with anhydrous ethanol, and vacuum dry at 70 ° C for 1.5 h to obtain silica lubricated nanospheres.

[0039] S6: 35g of acrylic acid grafted aniline, 165g of methacrylic acid modified epoxy resin, 13g of silica lubricated nanospheres and 2.5L of deionized water were added to a reactor, nitrogen protection was introduced, and the reaction was stirred at 98°C and 550r / min for 1.5h. The reaction was cooled to 60°C, and 8g of initiator sodium persulfate and 6.5g of cross-linking agent hydroxymethyl acrylamide were added to the reactor. The reaction was heated to 75°C and stirred at 550r / min for 3.5h. The reaction was filtered, and the filter cake was washed twice with deionized water and anhydrous ethanol respectively, dried in a vacuum at 70°C for 1.5h, crushed and granulated to obtain a highly wear-resistant water-based toughened epoxy resin coating.

[0040] Example 3: A method for preparing a highly wear-resistant water-based toughened epoxy resin coating, comprising the following steps: S1: Add 60 g of fluorinated hydroxyaniline and 300 mL of deionized water into a reactor, stir at 40°C and 500 r / min for 40 min, then add 40 g of sodium chloride, 40 mL of acetic acid solution and 30 mL of acetic anhydride, heat to 80°C, continue stirring for 5 h, cool naturally to room temperature, filter, and wash the filter cake with anhydrous ethanol and deionized water three times to obtain fluorinated acetanilide.

[0041] S2: 50 g of fluorinated acetanilide, 30 mL of 3-aminopropyltriethoxysilane, 200 mL of anhydrous ethanol and 300 mL of deionized water were added to a reactor, stirred at 85°C and 500 r / min for 2 h, then 60 mL of acrylic acid solution and 0.8 g of hydroquinone as a polymerization inhibitor were added, and the reaction was continued for 2 h. The mixture was filtered, and the filter cake was washed three times with deionized water and dried in vacuo at 80°C for 2 h to obtain acrylic acid-grafted acetanilide.

[0042] S3: 50 g of acrylic acid grafted acetanilide and 300 mL of deionized water were added to a reactor, followed by the addition of 5 g of sodium hydroxide. The mixture was stirred at 90°C and 500 rpm for 4 h, and naturally cooled to room temperature. 1 mol / L acetic acid solution was added to adjust the pH to 7, and the mixture was filtered. The filter cake was washed three times with anhydrous ethanol and deionized water, and vacuum dried at 80°C for 2 h to obtain acrylic acid grafted aniline.

[0043] S4: Add 300 mL of bisphenol A epoxy resin, 20 g of triphenylphosphine and 3 L of toluene into a reactor, stir at 110°C and 500 r / min for 50 min, then add 150 g of methacrylic acid and 3 g of hydroquinone as a polymerization inhibitor, continue stirring for 4 h, filter, wash the filter cake with anhydrous ethanol and deionized water three times, and vacuum dry at 80°C for 2 h to obtain methacrylic acid modified epoxy resin.

[0044] S5: Add 30 g of polystyrene microspheres with a particle size of 30 nm and 900 mL of deionized water into the reactor, stir at 25°C and 600 r / min for 40 min, then add 5 g of hexadecyltrimethylammonium bromide and 150 mL of tetraethyl silicate, continue stirring for 5 h, add 3.2 L of 2.0 M hydrochloric acid solution dropwise at a rate of 9 mL / min, continue stirring for 6 h, filter, wash the filter cake with N,N-dimethylformamide to remove the polystyrene template, then wash it with anhydrous ethanol three times, and vacuum dry it at 80°C for 2 h to obtain silica lubricated nanospheres.

[0045] S6: 40g of acrylic acid grafted aniline, 180g of methacrylic acid modified epoxy resin, 14g of silica lubricated nanospheres and 3L of deionized water were added to a reactor, nitrogen protection was introduced, and the reaction was stirred at 100°C and 600r / min for 2h. The reaction was cooled to 65°C, and 9g of initiator sodium persulfate and 8g of cross-linking agent hydroxymethyl acrylamide were added to the reactor. The reaction was heated to 80°C and stirred at 600r / min for 4h. The reaction was filtered, and the filter cake was washed with deionized water and anhydrous ethanol three times respectively. The mixture was vacuum dried at 80°C for 2h, crushed and granulated to obtain a highly wear-resistant water-based toughened epoxy resin coating.

[0046] Comparative Example 1: Based on Example 3, without the treatment in step S1, the fluorinated acetanilide in step S2 was replaced with fluorinated hydroxyaniline to prepare a highly wear-resistant water-based toughened epoxy resin coating.

[0047] Comparative Example 2: Based on Example 3, without the treatment in step S2, the acrylic acid-grafted acetanilide in step S3 was replaced with fluorinated acetanilide to prepare a highly wear-resistant water-based toughened epoxy resin coating.

[0048] Comparative Example 3: Based on Example 3, the methacrylic acid modified epoxy resin in step S6 is replaced by the bisphenol A epoxy resin in step S4 to prepare a highly wear-resistant water-based toughened epoxy resin coating.

[0049] Comparative Example 4: Based on Example 3, without the treatment in step S5, the silica lubricating nanospheres in step S6 were discarded to prepare a highly wear-resistant water-based toughened epoxy resin coating.

[0050] The performance of the highly wear-resistant water-based toughened epoxy resin coatings prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was tested. A highly wear-resistant water-based toughened epoxy resin coating was sprayed onto a tinplate using an electrostatic spray gun to a film thickness of 70-80 μm and cured at 150°C for 15 min to obtain the coating. Impact resistance was tested according to ISO 6272-80, with a dry film thickness of 2×150 μm. Abrasion resistance was tested according to GB / T 23988-2009, "Determination of Abrasion Resistance of Coatings - Falling Sand Method," where a larger value indicates more falling sand required per unit of coating film wear, indicating better abrasion resistance. Aging resistance was tested with reference to GB / T 1865-1997, "Aging Resistance of Standard Test Panels for Artificial Aging and Artificial Radiation Exposure (Filtered Xenon Arc Radiation) of Paints and Varnishes." Stain resistance was tested by mixing 100 g of fly ash and 100 g of water. Two test panels were taken, the coated side facing downward, and placed horizontally in a 1:1 fly ash and water solution for 5 seconds. The panels were then removed and naturally dried in a standard environment for 2 hours. The coating was then tested according to GB / T 1865-1997, "Aging Resistance of Standard Test Panels for Artificial Aging and Artificial Radiation Exposure (Filtered Xenon Arc Radiation)." The flushing test was conducted using the test apparatus and test method in GB / T 9780-1988. After five cycles, the test was evaluated according to the method in GB250-1995. The test consists of five pairs of matte gray cards, which are divided into five grades based on the discernible color difference, namely 5, 4, 3, 2, and 1. The test was observed according to the visual colorimetry method in GB / T 1766-1995. Salt spray test: The test was conducted according to the method in ASTM B117. The results are shown in Table 1. Table 1 Performance test results of high wear-resistant water-based toughened epoxy resin coating

[0051] As can be seen from Table 1, the high wear-resistant water-based toughened epoxy resin coatings prepared in Examples 1 to 3 have significantly better impact resistance, wear resistance, aging resistance and stain resistance than the comparative examples, indicating that the high wear-resistant water-based toughened epoxy resin coatings prepared by the present invention have excellent impact resistance, wear resistance and corrosion resistance, the coating has strong adhesion and is not easy to fall off, and is not easily aged or stained with oil.

[0052] In Comparative Example 1, fluorinated acetanilide is replaced with fluorinated hydroxyaniline. The amino group in fluorinated hydroxyaniline acts as a nucleophilic reagent to attack the carbonyl carbon of acetic anhydride, causing a nucleophilic addition reaction to generate acetanilide. The amino group is protected in advance. By converting fluorinated hydroxyaniline into fluorinated acetanilide, the carboxyl group of acrylic acid is prevented from reacting with the amino group during grafting of acrylic acid. The nitrogen atom of the amino group of aniline provides a lone pair of electrons to form a coordination bond with the empty orbital on the metal surface, forming a dense adsorption film to physically block the corrosive medium. If the amino group is reacted, the lone pair of electrons is occupied, the coordination ability is lost, and the corrosion resistance is reduced.

[0053] In Comparative Example 2, acrylic acid-grafted acetanilide was replaced with fluorinated acetanilide. Acrylic acid was grafted onto aniline using acrylic acid as a bridge, and the amino group was retained. In a subsequent step, the double bonds of the acrylic acid-grafted acetanilide and the double bonds in the methacrylic acid-modified epoxy resin were copolymerized under an initiator, thereby grafting aniline into the polymer chain to form a denser network structure. After modification, the crosslinking density of the resin was increased, and the hardness and scratch resistance were simultaneously enhanced.

[0054] In Comparative Example 3, the methacrylic acid-modified epoxy resin is replaced with bisphenol A epoxy resin. The bisphenol A epoxy resin opens its ring by attacking the epoxy group through the carboxyl group of methacrylic acid, and grafts the double bond to the surface of the epoxy resin, thereby copolymerizing with the subsequent acrylic acid-grafted acetanilide. After losing the double bond, the acrylic acid-grafted acetanilide is polymerized alone, and the resulting polymer is dispersed in the epoxy resin, with poor interfacial bonding and poor performance improvement.

[0055] In Comparative Example 4, the silica lubricating nanospheres were discarded, and the polystyrene microspheres were used as a template to cover the surface of the polystyrene microspheres with silica lubricating nanospheres. The polystyrene microspheres were then removed by N,N-dimethylformamide to obtain hollow silica lubricating nanospheres. The silica lubricating nanospheres dispersed in the epoxy resin coating can disperse stress by slipping, thereby improving the impact strength and wear resistance of the coating.

[0056] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing a highly wear-resistant water-based toughened epoxy resin coating, characterized in that: The steps include: Acrylic acid grafted aniline, methacrylic acid modified epoxy resin, silica lubricating nanospheres and deionized water are added to a reactor, nitrogen is introduced for protection, and the reaction is carried out at 95-100° C. and 500-600 r / min with stirring for 1-2 hours. The reaction is cooled to 55-65° C., sodium persulfate and hydroxymethyl acrylamide are added to the reactor, and the reaction is heated to 70-80° C. and stirred at 500-600 r / min for 3-4 hours. The reaction is filtered, washed, vacuum dried, crushed and granulated to obtain a highly wear-resistant water-based toughened epoxy resin coating.

2. The method for preparing a highly wear-resistant water-based toughened epoxy resin coating according to claim 1, wherein: The usage ratio of the acrylic acid grafted aniline, methacrylic acid modified epoxy resin, silicon dioxide lubricating nanospheres, deionized water, sodium persulfate and hydroxymethyl acrylamide is 30-40g: 150-180g: 12-14g: 2-3L: 7-9g: 5-8g.

3. The method for preparing a highly wear-resistant water-based toughened epoxy resin coating according to claim 1, wherein: The acrylic acid grafted aniline is prepared by the following steps: Acrylic acid grafted acetanilide and deionized water are added to a reaction kettle, and then sodium hydroxide is added, and the mixture is stirred at 80-90° C. and 400-500 r / min for 3-4 hours, cooled naturally, and 1 mol / L acetic acid solution is added to adjust the pH value to 6-7. The mixture is filtered, washed, and vacuum dried to obtain acrylic acid grafted aniline.

4. The method for preparing a highly wear-resistant water-based toughened epoxy resin coating according to claim 3, wherein: The usage ratio of acrylic acid grafted acetanilide, deionized water and sodium hydroxide is 40-50 g: 200-300 mL: 4-5 g.

5. The method for preparing a highly wear-resistant water-based toughened epoxy resin coating according to claim 3, characterized in that: The acrylic acid grafted acetanilide is prepared by the following steps: Add fluorinated acetanilide, 3-aminopropyltriethoxysilane, anhydrous ethanol and deionized water into a reactor, stir at 80-85°C and 400-500 r / min for 1-2 hours, then add acrylic acid solution and hydroquinone, continue to react for 1-2 hours, filter, wash and vacuum dry to obtain acrylic acid-grafted acetanilide.

6. The method for preparing a highly wear-resistant water-based toughened epoxy resin coating according to claim 5, characterized in that: The usage ratio of the fluorinated acetanilide, 3-aminopropyltriethoxysilane, anhydrous ethanol, deionized water, acrylic acid solution and hydroquinone is 40-50 g: 20-30 mL: 180-200 mL: 200-300 mL: 50-60 mL: 0.5-0.8 g.

7. The method for preparing a highly wear-resistant water-based toughened epoxy resin coating according to claim 5, characterized in that: The fluorinated acetanilide is prepared by the following steps: Add fluorinated hydroxyaniline and deionized water into a reaction kettle, stir at 35-40°C and 400-500 r / min for 30-40 minutes, then add sodium chloride, acetic acid solution and acetic anhydride, heat to 70-80°C, continue stirring for 4-5 hours, cool naturally, filter, and wash to obtain fluorinated acetanilide; The usage ratio of the fluorinated hydroxyaniline, deionized water, sodium chloride, acetic acid solution and acetic anhydride is 50-60 g: 200-300 mL: 30-40 g: 30-40 mL: 20-30 mL.

8. The method for preparing a highly wear-resistant water-based toughened epoxy resin coating according to claim 1, characterized in that: The methacrylic acid modified epoxy resin is prepared by the following steps: Add bisphenol A epoxy resin, triphenylphosphine and toluene into a reaction kettle, stir at 100-110°C and 400-500 r / min for 40-50 minutes, then add methacrylic acid and hydroquinone, continue stirring for 3-4 hours, filter, wash and vacuum dry to obtain methacrylic acid modified epoxy resin.

9. The method for preparing a highly wear-resistant water-based toughened epoxy resin coating according to claim 8, characterized in that: The usage ratio of the bisphenol A epoxy resin, triphenylphosphine, toluene, methacrylic acid and hydroquinone is 200-300 mL: 15-20 g: 2-3 L: 120-150 g: 2.5-3 g.

10. The method for preparing a highly wear-resistant water-based toughened epoxy resin coating according to claim 1, characterized in that: The silica lubricating nanospheres are prepared by the following steps: Add polystyrene microspheres and deionized water into a reactor, stir at 20-25°C and 500-600 r / min for 30-40 minutes, then add hexadecyltrimethylammonium bromide and tetraethyl silicate, continue stirring for 4-5 hours, add 2.0M hydrochloric acid solution dropwise at a rate of 8-9 mL / min, continue stirring for 5-6 hours, filter, wash the filter cake with N,N-dimethylformamide to remove the polystyrene template, then wash with anhydrous ethanol 2-3 times, and vacuum dry to obtain silica lubricated nanospheres; The usage ratio of the polystyrene microspheres to deionized water, hexadecyltrimethylammonium bromide, tetraethyl silicate and hydrochloric acid solution is 20-30 g: 800-900 mL: 4-5 g: 120-150 mL: 3-3.2 L.

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