Waterborne wear-resistant epoxy coating and preparation method thereof

Abstract

The invention relates to the field of coatings, and particularly discloses a water-based wear-resistant epoxy coating and a preparation method thereof.The water-based wear-resistant epoxy coating is prepared from water-based epoxy resin, a water-based curing agent, a dispersing agent, a defoaming agent, a flatting agent, water and core-shell filler, generating a polydopamine shell layer in situ in an alkaline buffer solution by using dopamine hydrochloride; the preparation method comprises the following steps: mixing the water-borne epoxy resin, the dispersing agent and part of water, and dispersing to form a base material; then adding the core-shell filler, stirring, adding the defoaming agent, the flatting agent and the remaining water, and stirring; and cooling, adding the water-based curing agent, stirring and standing to obtain the water-based wear-resistant epoxy coating. The prepared waterborne epoxy coating has the characteristic of better wear resistance.

Description

Technical Field

[0001] This application relates to the field of coatings, and more specifically, to a water-based wear-resistant epoxy coating and a method for preparing the same. Background Technology

[0002] Epoxy coatings are widely used in industrial corrosion protection, flooring, and machinery protection due to their excellent adhesion, chemical resistance, and mechanical strength. However, traditional solvent-based epoxy coatings have poor environmental performance. Solvent-based epoxy resins contain a large amount of organic solvents, resulting in high emissions of volatile organic compounds (VOCs).

[0003] Waterborne epoxy coatings use water as the dispersion medium, and the VOC content can be reduced to 50g / L, making them an environmentally friendly alternative. However, the wear resistance, hardness, and corrosion resistance of waterborne epoxy coatings are still significantly lower than those of solvent-based products. The main reasons are: waterborne epoxy resins have a lower molecular weight, resulting in insufficient cross-linking density after film formation, leading to poor coating density and easy scratching by hard particles. The wear resistance is only 30-50% of that of solvent-based coatings. Secondly, traditional wear-resistant fillers such as silica tend to agglomerate in waterborne systems due to their surface polarity differences, forming stress concentration points and reducing coating performance.

[0004] With the rapid development of emerging industries such as intelligent manufacturing, transportation and new energy, the market demand for environmentally friendly and highly wear-resistant coatings has surged. Therefore, there is an urgent need to further develop waterborne epoxy coatings to improve their wear resistance. Summary of the Invention

[0005] In order to obtain a waterborne epoxy coating with better wear resistance, this application provides a waterborne wear-resistant epoxy coating and its preparation method.

[0006] In a first aspect, this application provides a water-based wear-resistant epoxy coating, which adopts the following technical solution: A water-based abrasion-resistant epoxy coating comprises the following raw materials in parts by weight: 40-60 parts waterborne epoxy resin, 10-20 parts waterborne curing agent, 0.5-2 parts dispersant, 0.2-1 part defoamer, 0.3-1.2 parts leveling agent, 25-30 parts water and 5-15 parts core-shell filler, wherein the core-shell filler uses nano-silica as the core material and generates a polydopamine shell in situ with dopamine hydrochloride in an alkaline buffer solution.

[0007] By adopting the above technical solution, the waterborne epoxy resin in this application is used as the base resin and crosslinked with the waterborne curing agent to form a three-dimensional network polymer. The crosslinked structure gives the coating film high strength and hardness, providing a basis for the wear resistance of the coating. On this basis, the application adds core-shell fillers. The addition of nanofillers can fill the micro-defects in the coating film and increase the density. In particular, nano-silica has extremely high hardness. Its nano-size effect is dispersed in the coating film, filling the voids and defects in the coating film, improving the density, thereby enhancing the hardness and wear resistance of the coating film. Dopamine hydrochloride forms a polydopamine shell in situ in an alkaline buffer solution. Polydopamine has good adhesion and reactivity. Its surface amino groups can interact with epoxy groups in epoxy resin to form a cross-linked network structure. In addition, polydopamine molecules also contain catechol groups, which can form covalent bonds with active groups in epoxy resin or curing agent. This further enhances the interfacial bonding force between polydopamine and epoxy resin, making the nanofiller more uniformly dispersed during coating. It can also reduce the agglomeration of nanoparticles, which helps the nanofiller to embed into the epoxy resin matrix, improves density, and further improves its wear resistance.

[0008] Optionally, the core-shell packing material is prepared by the following methods: 1) Tris buffer solution was prepared by dissolving tris(hydroxymethyl)aminomethane in water and adjusting the pH to 8.5 with hydrochloric acid. 2) Disperse nano-silica in Tris buffer, sonicate for 10-20 min, then add dopamine hydrochloride, stir, react for 8-10 h, centrifuge, wash with water, and dry to obtain core-shell packing material.

[0009] By adopting the above technical solution, in an alkaline environment, dopamine undergoes an oxidative self-polymerization reaction on the surface of nano-silica to form a polydopamine coating layer. Its amino and hydroquinone active groups or molecules can form chemical bonds with epoxy resin and nano-silica, improving interfacial bonding. At the same time, the polydopamine shell improves its dispersibility in the epoxy resin matrix through steric hindrance and charge repulsion, reducing agglomeration and improving wear resistance.

[0010] Optionally, during the preparation of the core-shell packing material, in step 1), the molar concentration of tris(hydroxymethyl)aminomethane in the Tris buffer is 10-15 mmol / L; In step 2), the amount of nano-silica added to Tris buffer is 1-3 g / 100 mL, and the mass ratio of dopamine hydrochloride to nano-silica is 1:(3-5).

[0011] By adopting the above technical solution, the core-shell filler prepared by controlling the above addition amount has better wear resistance when used in coatings.

[0012] Optionally, during the preparation of the core-shell filler, in step 2), after dispersing nano-silica in Tris buffer and sonicating it, N-β-aminoethyl-γ-aminopropyltrimethoxysilane is first added and stirred for 40-60 min. Then, 3-glycidoxypropyltrimethoxysilane is added and stirred for another 20-30 min before adding dopamine hydrochloride.

[0013] By adopting the above technical solution, this application adds an N-β-aminoethyl-γ-aminopropyltrimethoxysilane and 3-glycidyl etheroxypropyltrimethoxysilane (GPTMS) bissilane system before adding dopamine hydrochloride. First, N-β-aminoethyl-γ-aminopropyltrimethoxysilane containing amino groups is added. Its amino groups preferentially react with the hydroxyl groups on the surface of silica to form a silicon-oxygen framework and expose the amino groups to guide the directional deposition of dopamine. Then, 3-glycidyl etheroxypropyltrimethoxysilane containing epoxy groups is added. It is embedded in the intermediate layer and provides epoxy groups that are compatible with epoxy resin to form a gradient transition interface.

[0014] The methoxy group of 3-glycidoxypropyltrimethoxysilane hydrolyzes to form silanol groups, which can form chemical bonds with nano-silica. After modification, epoxy groups are introduced into the surface of nano-silica. These groups have similar structures to epoxy resin groups and have better compatibility with epoxy resin. In addition, the catechol groups in polydopamine can also form cross-linked structures with the epoxy groups of GPTMS and with the epoxy resin matrix, which enhances the density of the coating system and further improves wear resistance.

[0015] Optionally, the amount of N-β-aminoethyl-γ-aminopropyltrimethoxysilane added is 12-15 wt% of nano-silica, and the amount of 3-glycidyl etheroxypropyltrimethoxysilane added is 5-8 wt% of nano-silica.

[0016] Optionally, during the preparation of the core-shell filler, in step 2), while adding dopamine hydrochloride, glycidyl methacrylate is also added, and the amount of glycidyl methacrylate added is 5-10 wt% of nano-silica.

[0017] By adopting the above technical solution, when glycidyl methacrylate is added, under alkaline conditions, dopamine self-polymerizes to form a polydopamine shell. At the same time, glycidyl methacrylate, as a comonomer, forms covalent bonds with the hydroxyl groups on the surface of nano-silica through epoxy groups, and also interacts with the active groups in waterborne epoxy resin to enhance the interfacial bonding between the filler and the epoxy resin matrix. Moreover, the introduction of epoxy groups can also increase the crosslinking density of the shell and improve wear resistance.

[0018] Optionally, during the preparation of the core-shell packing material, the core-shell packing material obtained in step 2) is added after post-modification treatment. The post-modification treatment operation is as follows: A mercaptoacetic acid solution was prepared by dissolving mercaptoacetic acid in a Tris buffer solution with a molar concentration of 50 mM and a pH of 8.5. The concentration of mercaptoacetic acid in the Tris buffer solution was 10-20 mg / mL. The obtained core-shell packing material was then dispersed in a mercaptoacetic acid solution at a mass ratio of 1:(2-3). The mixture was stirred at room temperature for 2-3 hours. After the reaction was completed, the mixture was centrifuged and washed to obtain the post-treated core-shell packing material.

[0019] Although the abundant catechol structures and primary amine groups on polydopamine can participate in the curing of epoxy resin by adopting the above technical solution, their crosslinking reaction is limited due to their large steric hindrance. Therefore, in this application, after polymerizing the surface of nano-silica to form a polydopamine shell, the quinone groups on the polydopamine shell are used to react with mercaptoacetic acid containing mercapto groups to introduce carboxyl groups. The carboxyl groups can form controllable crosslinks with epoxy resin or curing agent, further improving the crosslinking density and the chemical bonding between the filler and the resin matrix, thereby improving wear resistance.

[0020] Optionally, an amine-based curing agent, a polyethylene glycol-type polyol dispersant, an organosilicon defoamer, and a modified organosilicon leveling agent can be selected as the curing agent, dispersant, defoamer, and leveling agent.

[0021] Secondly, this application provides a method for preparing a water-based wear-resistant epoxy coating, using the following technical solution: A method for preparing a water-based wear-resistant epoxy coating includes the following steps: Mix waterborne epoxy resin, dispersant and 1 / 3-2 / 3 water, and disperse at a speed of 1000-1200 r / min for 10-15 min to form a base material; Then add the core-shell filler to the base material, continue stirring for 20-30 minutes, then add the defoamer, leveling agent and the remaining water, and stir for 20-30 minutes. After cooling to 20-25℃, add water-based curing agent, stir at 300-500r / min for 15-20min, and then let stand for 5-15min to obtain water-based wear-resistant epoxy coating.

[0022] By adopting the above technical solution, the method provided in this application is simple, convenient, and easy to operate.

[0023] In summary, this application has the following beneficial effects: 1. This application includes a core-shell filler. The addition of nanofillers can fill microscopic defects in the coating film, increase density, and thus enhance the hardness and wear resistance of the coating film. On this basis, dopamine hydrochloride generates a polydopamine shell in situ in an alkaline buffer solution. Polydopamine has good adhesion and reactivity. Its surface amino groups can interact with epoxy groups in epoxy resin to form a cross-linked network structure. Moreover, polydopamine molecules also contain catechol groups, which can form covalent bonds with active groups in epoxy resin or curing agent. This further enhances the interfacial bonding force between polydopamine and epoxy resin, making the nanofiller more uniformly dispersed during coating. It can also reduce the agglomeration of nanoparticles, which helps the nanofiller to embed into the epoxy resin matrix, improve density, and further improve its wear resistance. 2. In this application, before adding dopamine hydrochloride, an N-β-aminoethyl-γ-aminopropyltrimethoxysilane and 3-glycidyl etheroxypropyltrimethoxysilane (GPTMS) bissilane system is added. First, N-β-aminoethyl-γ-aminopropyltrimethoxysilane containing amino groups is added. Its amino groups preferentially react with the hydroxyl groups on the surface of silica to form a silicon-oxygen framework and expose the amino groups to guide the directional deposition of dopamine. Then, 3-glycidyl etheroxypropyltrimethoxysilane containing epoxy groups is added. It is embedded in the intermediate layer to provide epoxy groups that are compatible with epoxy resin, forming a gradient transition interface. This results in better compatibility with epoxy resin and further improves wear resistance. Detailed Implementation

[0024] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0025] In the following examples, the water-based curing agent is an amine-based curing agent, and more specifically, AB-HGF-100 water-based epoxy curing agent from Zhejiang Anbang New Material Development Co., Ltd. The waterborne epoxy resin used is the S-48 model product sold by Guangdong Shuntian New Materials Co., Ltd. The dispersant used is a polyethylene glycol-type polyol dispersant, specifically PEG-1000. The defoamer used is an organosilicon defoamer, specifically the BYK1765 defoamer from Dongguan Caihua Plastics Technology Co., Ltd., for use in epoxy resin systems. The leveling agent used is a modified silicone leveling agent, specifically the silicone leveling agent HY-307N from Shanghai Huiyan New Materials Co., Ltd., whose main component is polyether-modified polysiloxane.

[0026] The following preparation examples are examples of core-shell packing material preparation. Preparation Example 1 A method for preparing a core-shell packing material includes the following steps: 1) Tris buffer was prepared by dissolving tris(hydroxymethyl)aminomethane in water and adjusting the pH to 8.5 with hydrochloric acid. The molar concentration of tris(hydroxymethyl)aminomethane in the Tris buffer was 12 mmol / L. 2) Disperse nano-silica in Tris buffer at a concentration of 2 g / 100 mL (i.e., add 2 g of nano-silica per 100 mL of Tris buffer), sonicate for 15 min, then add 4-methoxydopamine hydrochloride at a mass ratio of 1:4, stir, react for 9 h, centrifuge, wash with water, and dry to obtain the core-shell packing material.

[0027] Preparation Example 2 A method for preparing a core-shell packing material includes the following steps: 1) Tris buffer was prepared by dissolving tris(hydroxymethyl)aminomethane in water and adjusting the pH to 8.5 with hydrochloric acid. The molar concentration of tris(hydroxymethyl)aminomethane in the Tris buffer was 10 mmol / L. 2) Disperse nano-silica in Tris buffer at a concentration of 1 g / 100 mL (i.e., add 1 g of nano-silica per 100 mL of Tris buffer), sonicate for 10 min, then add 4-methoxydopamine hydrochloride at a mass ratio of 1:3 to nano-silica, stir, react for 8 h, centrifuge, wash with water, and dry to obtain the core-shell packing material.

[0028] Preparation Example 3 A method for preparing a core-shell packing material includes the following steps: 1) Tris buffer was prepared by dissolving tris(hydroxymethyl)aminomethane in water and adjusting the pH to 8.5 with hydrochloric acid. The molar concentration of tris(hydroxymethyl)aminomethane in the Tris buffer was 15 mmol / L. 2) Disperse nano-silica in Tris buffer at a concentration of 3 g / 100 mL (i.e., add 1-3 g of nano-silica per 100 mL of Tris buffer), sonicate for 20 min, then add 4-methoxydopamine hydrochloride at a mass ratio of 1:5 to nano-silica, stir, react for 10 h, centrifuge, wash with water, and dry to obtain the core-shell packing material.

[0029] Preparation Example 4 A method for preparing a core-shell packing material is carried out according to the method in Preparation Example 1, except that in step 2), after dispersing nano-silica in Tris buffer and sonicating it, N-β-aminoethyl-γ-aminopropyltrimethoxysilane (KH-792) is first added, and after stirring for 50 min, 3-glycidoxypropyltrimethoxysilane (KH-560) is added, and after stirring for 25 min, 4-methoxydopamine hydrochloride is added.

[0030] The amount of N-β-aminoethyl-γ-aminopropyltrimethoxysilane added is 13 wt% of nano-silica, and the amount of 3-glycidyl etheroxypropyltrimethoxysilane added is 6 wt% of nano-silica.

[0031] Preparation Example 5 A method for preparing a core-shell packing material is carried out according to the method in Preparation Example 1, except that in step 2), after dispersing nano-silica in Tris buffer and sonicating it, N-β-aminoethyl-γ-aminopropyltrimethoxysilane (KH-792) is first added, and after stirring for 40 min, 3-glycidoxypropyltrimethoxysilane (KH-560) is added, and after stirring for another 20 min, 4-methoxydopamine hydrochloride is added.

[0032] The amount of N-β-aminoethyl-γ-aminopropyltrimethoxysilane added is 12 wt% of nano-silica, and the amount of 3-glycidyl etheroxypropyltrimethoxysilane added is 5 wt% of nano-silica.

[0033] Preparation Example 6 A method for preparing a core-shell packing material is carried out according to the method in Preparation Example 1, except that in step 2), after dispersing nano-silica in Tris buffer and sonicating it, N-β-aminoethyl-γ-aminopropyltrimethoxysilane (KH-792) is first added, and after stirring for 60 min, 3-glycidoxypropyltrimethoxysilane (KH-560) is added, and after stirring for another 30 min, 4-methoxydopamine hydrochloride is added.

[0034] The amount of N-β-aminoethyl-γ-aminopropyltrimethoxysilane added is 15 wt% of nano-silica, and the amount of 3-glycidyl etheroxypropyltrimethoxysilane added is 8 wt% of nano-silica.

[0035] Preparation Example 7 A method for preparing a core-shell packing material is carried out according to the method in Preparation Example 4, except that in step 2), KH-792 and KH-560 are replaced with KH-550 in equal amounts.

[0036] Preparation Example 8 A method for preparing a core-shell filler is carried out according to the method in Preparation Example 4, except that in step 2), 4-methoxydopamine hydrochloride is added along with glycidyl methacrylate, and the amount of glycidyl methacrylate added is 7 wt% of nano-silica.

[0037] Preparation Example 9 A method for preparing a core-shell filler is carried out according to the method in Preparation Example 4, except that in step 2), 4-methoxydopamine hydrochloride is added along with glycidyl methacrylate, and the amount of glycidyl methacrylate added is 5 wt% of nano-silica.

[0038] Preparation Example 10 A method for preparing a core-shell filler is carried out according to the method in Preparation Example 4, except that in step 2), 4-methoxydopamine hydrochloride is added along with glycidyl methacrylate, and the amount of glycidyl methacrylate added is 10 wt% of nano-silica.

[0039] Example 1 A method for preparing a water-based wear-resistant epoxy coating includes the following steps: Mix 50 kg of waterborne epoxy resin, 1 kg of dispersant and 20 kg of water, and disperse at 1100 r / min for 12 min to form a base material; Then add 10 kg of the core-shell filler prepared in Preparation Example 1 to the base material, continue stirring for 25 min, then add 0.5 kg of defoamer, 0.6 kg of leveling agent and 8 kg of water, and stir for 20-30 min; After cooling to 20°C, add 15 kg of water-based curing agent, stir at 400 r / min for 20 min, and then let stand for 10 min to obtain water-based wear-resistant epoxy coating.

[0040] Example 2 A method for preparing a water-based wear-resistant epoxy coating includes the following steps: Mix 40 kg of waterborne epoxy resin, 0.5 kg of dispersant and 8.5 kg of water, and disperse at 1000 r / min for 10 min to form a base material; Then, add 5 kg of the core-shell filler prepared in Preparation Example 2 to the base material, continue stirring for 20 min, then add 0.2 kg of defoamer, 0.3 kg of leveling agent and 11.5 kg of water, and stir for 20 min. After cooling to 20℃, add 10kg of water-based curing agent, stir at 300r / min for 15min, and then let stand for 5min to obtain water-based wear-resistant epoxy coating.

[0041] Example 3 A method for preparing a water-based wear-resistant epoxy coating includes the following steps: Mix 60 kg of waterborne epoxy resin, 2 kg of dispersant and 20 kg of water, and disperse at 1200 r / min for 15 min to form a base material; Then, add 15 kg of the core-shell filler prepared in Preparation Example 3 to the base material, continue stirring for 30 min, then add 1 kg of defoamer, 1.2 kg of leveling agent and 10 kg of water, and stir for 30 min. After cooling to 25°C, add 20 kg of water-based curing agent, stir at 500 r / min for 20 min, and then let stand for 15 min to obtain water-based wear-resistant epoxy coating.

[0042] Examples 4-10 A method for preparing a water-based wear-resistant epoxy coating is carried out according to the method in Example 1, except that the core and shell fillers are selected from the core and shell fillers prepared in Examples 4-10.

[0043] Example 11 A method for preparing a water-based wear-resistant epoxy coating is carried out according to the method in Example 4, except that the core-shell filler is added after post-modification treatment. The specific post-modification operation is as follows: Tris buffer solution with a molar concentration of 50 mM (the molar concentration of tris(hydroxymethyl)aminomethane in Tris was 50 mmol / L) and pH 8 was prepared by dissolving tris(hydroxymethyl)aminomethane in water and adjusting the pH to 8.5 with hydrochloric acid. Then, thioglycolic acid was dissolved in Tris buffer with a molar concentration of 50 mM and a pH of 8.5 to prepare a thioglycolic acid solution with a concentration of 15 mg / mL in Tris buffer. Then, the core-shell packing material prepared in Preparation Example 4 was dispersed in a mercaptoacetic acid solution at a mass ratio of 1:2.5. The mixture was stirred at room temperature for 2.5 hours. After the reaction was completed, the mixture was centrifuged and washed to obtain the post-treated core-shell packing material. The post-treated core-shell packing material was then added to the base material.

[0044] Example 12 A method for preparing a water-based wear-resistant epoxy coating is carried out according to the method in Example 4, except that the core-shell filler is added after post-modification treatment. The specific post-modification operation is as follows: Tris buffer solution with a molar concentration of 50 mM (the molar concentration of tris(hydroxymethyl)aminomethane in Tris was 50 mmol / L) and pH 8 was prepared by dissolving tris(hydroxymethyl)aminomethane in water and adjusting the pH to 8.5 with hydrochloric acid. Then, thioglycolic acid was dissolved in Tris buffer with a molar concentration of 50 mM and a pH of 8.5 to prepare a thioglycolic acid solution with a concentration of 10 mg / mL in Tris buffer. Then, the core-shell packing material prepared in Preparation Example 4 was dispersed in a mercaptoacetic acid solution at a mass ratio of 1:2. The mixture was stirred at room temperature for 2 hours. After the reaction was completed, the mixture was centrifuged and washed to obtain the post-treated core-shell packing material. The post-treated core-shell packing material was then added to the base material.

[0045] Example 13 A method for preparing a water-based wear-resistant epoxy coating is carried out according to the method in Example 4, except that the core-shell filler is added after post-modification treatment. The specific post-modification operation is as follows: Tris buffer solution with a molar concentration of 50 mM (the molar concentration of tris(hydroxymethyl)aminomethane in Tris was 50 mmol / L) and pH 8 was prepared by dissolving tris(hydroxymethyl)aminomethane in water and adjusting the pH to 8.5 with hydrochloric acid. Then, thioglycolic acid was dissolved in Tris buffer with a molar concentration of 50 mM and a pH of 8.5 to prepare a thioglycolic acid solution with a concentration of 20 mg / mL in Tris buffer. Then, the core-shell packing material prepared in Preparation Example 4 was dispersed in a mercaptoacetic acid solution at a mass ratio of 1:3. The mixture was stirred at room temperature for 3 hours. After the reaction was completed, the mixture was centrifuged and washed to obtain the post-treated core-shell packing material. The post-treated core-shell packing material was then added to the base material.

[0046] Comparative Example 1 A method for preparing a water-based wear-resistant epoxy coating is carried out according to the method in Example 1, except that the core-shell filler is replaced with an equal amount of nano-silica.

[0047] Comparative Example 2 A method for preparing a water-based wear-resistant epoxy coating is carried out according to the method in Example 1, except that the core-shell filler is replaced with an equal amount of nano-silica, and silane coupling agent KH-550 is added in addition to nano-silica, and the amount of KH-550 added is 10 wt% of nano-silica.

[0048] Performance testing The epoxy coatings prepared in the above examples and comparative examples were coated onto cold-rolled steel plates to prepare coating tests according to the method in GB / T 1768-2006. The dry film thickness was 30 μm. The Taber wear resistance test was carried out using a CS-10 grinding wheel under a 1000g load for 1000 revolutions. The mass loss was statistically analyzed, and the results are shown in Table 1 below.

[0049] Table 1: Referring to the test results in Table 1 above, the epoxy coating prepared in this application exhibits excellent wear resistance, with a wear mass <50mg. Combined with the test results in Examples 1-3, the core-shell filler in this application utilizes nano-silica hardness and nano-filling to increase density. A cross-linking network is formed between the polydopamine layer and epoxy groups, reducing nano-filler agglomeration and improving dispersibility while increasing cross-linking density. Ultimately, the core-shell bonding reduces agglomeration through chemical bonding and steric hindrance, enhancing coating density and significantly improving wear resistance. Furthermore, combining the test results from Examples 1 and 4-6... Tests have shown that after nano-silica is dispersed in Tris buffer, it first passes through N-β-aminoethyl-γ-aminopropyltrimethoxysilane, which directionally guides the polymerization of dopamine. Meanwhile, 3-glycidyl etheroxypropyltrimethoxysilane is embedded in the shell to form a gradient transition interface, which enhances the compatibility with epoxy resin and further improves wear resistance. Combined with the test results of Example 7, when only ordinary aminosilane coupling agent is added, the wear resistance is significantly insufficient compared to Example 4. The gradient interface in Examples 4-6 is more conducive to the compatibility with epoxy resin matrix and improves wear resistance.

[0050] Combining the test results of Examples 1 and 8-10, the wear resistance was further improved when dopamine hydrochloride was added along with glycidyl methacrylate. The introduction of epoxy group monomers further improved the compatibility in the epoxy resin matrix. Combining the test results of Examples 11-13, the introduction of carboxyl groups after post-treatment of the core-shell filler can form additional cross-linking points, further improving the wear resistance. Combining the test results of Comparative Examples 1 and 2, the poor dispersibility and interfacial bonding with the resin matrix when nano-silica was added directly resulted in poor wear resistance. In Comparative Example 2, nano-silica and silane coupling agent were added simultaneously, which improved the wear resistance compared to Comparative Example 1, but it was still much weaker than that of Example 1.

[0051] In addition, the epoxy coatings prepared in Examples 1-13 of this application were subjected to an 800-hour salt spray resistance test in accordance with GB / T 1771-2007. No rusting or peeling was observed after 800 hours, indicating excellent salt spray resistance.

[0052] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A water-based wear-resistant epoxy coating, characterized in that, Including the following parts by weight of raw materials: The mixture comprises 40-60 parts waterborne epoxy resin, 10-20 parts waterborne curing agent, 0.5-2 parts dispersant, 0.2-1 part defoamer, 0.3-1.2 parts leveling agent, 25-30 parts water, and 5-15 parts core-shell filler, wherein the core-shell filler is added after post-modification treatment. The post-modification treatment procedure is as follows: A mercaptoacetic acid solution was prepared by dissolving mercaptoacetic acid in a Tris buffer solution with a molar concentration of 50 mM and a pH of 8.

5. The concentration of mercaptoacetic acid in the Tris buffer solution was 10-20 mg / mL. The obtained core-shell packing material was then dispersed in a mercaptoacetic acid solution at a mass ratio of 1:(2-3). The mixture was stirred at room temperature for 2-3 hours. After the reaction was complete, the mixture was centrifuged and washed to obtain the post-treated core-shell packing material. The core-shell packing material was prepared by the following method: 1) Tris buffer solution was prepared by dissolving tris(hydroxymethyl)aminomethane in water and adjusting the pH to 8.5 with hydrochloric acid. 2) Disperse nano-silica in Tris buffer, sonicate for 10-20 min, then add dopamine hydrochloride, stir, react for 8-10 h, centrifuge, wash with water, and dry to obtain core-shell packing material; In step 2), after dispersing nano-silica in Tris buffer and sonicating it, N-β-aminoethyl-γ-aminopropyltrimethoxysilane is first added and stirred for 40-60 min. Then, 3-glycidoxypropyltrimethoxysilane is added and stirred for another 20-30 min before adding dopamine hydrochloride.

2. The water-based wear-resistant epoxy coating according to claim 1, characterized in that: In the preparation of the core-shell packing material, in step 1), the molar concentration of tris(hydroxymethyl)aminomethane in the Tris buffer is 10-15 mmol / L; In step 2), the amount of nano-silica added to Tris buffer is 1-3 g / 100 mL, and the mass ratio of dopamine hydrochloride to nano-silica is 1:(3-5).

3. The water-based wear-resistant epoxy coating according to claim 1, characterized in that: The amount of N-β-aminoethyl-γ-aminopropyltrimethoxysilane added is 12-15 wt% of nano-silica, and the amount of 3-glycidyl etheroxypropyltrimethoxysilane added is 5-8 wt% of nano-silica.

4. The water-based wear-resistant epoxy coating according to claim 1, characterized in that: During the preparation of the core-shell filler, in step 2), while adding dopamine hydrochloride, glycidyl methacrylate is also added, and the amount of glycidyl methacrylate added is 5-10 wt% of nano-silica.

5. The water-based wear-resistant epoxy coating according to claim 1, characterized in that: The water-based curing agent is an amine-based curing agent, the dispersant is a polyethylene glycol-type polyol dispersant, the defoamer is an organosilicon defoamer, and the leveling agent is a modified organosilicon leveling agent.

6. The method for preparing the waterborne wear-resistant epoxy coating as described in any one of claims 1-5, characterized in that: Includes the following steps: Mix waterborne epoxy resin, dispersant and 1 / 3-2 / 3 water, and disperse at a speed of 1000-1200 r / min for 10-15 min to form a base material; Then add the post-treatment core-shell filler to the base material, continue stirring for 20-30 minutes, then add the defoamer, leveling agent and the remaining water, and stir for 20-30 minutes. After cooling to 20-25℃, add water-based curing agent, stir at 300-500r / min for 15-20min, and then let stand for 5-15min to obtain water-based wear-resistant epoxy coating.

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