Preparation method of high-wear-resistance anticorrosive coating for metal tool

Abstract

The invention discloses a preparation method of a high-wear-resistance anticorrosive coating for a metal tool, and relates to the technical field of anticorrosive coatings. Comprising the four steps of substrate pretreatment, bottom coating layer coating, middle coating layer coating and surface coating layer coating. After a substrate is subjected to ultrasonic cleaning and polishing treatment, the epoxy resin bottom coating is coated, the polyurethane middle coating containing the modified nano silicon dioxide additive is coated after curing, and then the fluorocarbon resin surface coating with weather resistance and chemical corrosion resistance is coated. The coating prepared by the method has good corrosion resistance, wear resistance and chemical resistance, and is suitable for corrosion prevention requirements of metal tools in various harsh environments.

Description

Technical Field

[0001] The invention relates to the technical field of anti-corrosion coatings, in particular to a method for preparing a highly wear-resistant anti-corrosion coating for metal tools. Background Art

[0002] Metal hooks, used in metal tools, are widely used as connecting and carrying tools in various fields, including industry, construction, marine transportation, aerospace, and daily life. Their importance is self-evident. These hooks are typically made of metal materials such as steel, aluminum, or their alloys, which are highly valued for their excellent strength and workability. However, in harsh environments such as humidity, acidity, alkali, and salt spray, the surface of metal hooks is highly susceptible to corrosion.

[0003] Corrosion not only gradually weakens the mechanical properties of hooks, but also causes surface defects such as rust spots and pits. In severe cases, it can even cause the hook to break or fail. Especially in critical fields such as marine engineering, petrochemicals, and bridge construction, hook failure can lead to extremely serious safety accidents. Therefore, how to effectively extend the service life of hooks in corrosive environments has become a critical issue that needs to be addressed within the industry.

[0004] Currently, the industry generally uses surface anti-corrosion coatings to improve the corrosion resistance of metal hooks. However, while traditional anti-corrosion coatings such as paint, galvanizing, and chrome plating can provide some protection for metal hooks, their effectiveness is limited. Over time, these coatings may peel, crack, or fail, especially in extreme environments, significantly compromising their protective effectiveness. Furthermore, these traditional anti-corrosion coatings lack adhesion and wear resistance, making them susceptible to mechanical wear during use, exposing the metal substrate to corrosive media and accelerating the corrosion process.

[0005] Therefore, finding a more durable and effective anti-corrosion coating to extend the service life of metal hooks in corrosive environments has become a technical challenge that needs to be overcome urgently in the industry.

[0006] Chinese patent CN119186966A discloses a method for preparing a high-adhesion composite coating for metal products, relating to the field of metal surface treatment technology. The coating utilizes a polyurethane resin as a matrix, with the addition of a curing agent, an elastomer modifier, a lubricant, and an adhesion promoter to enhance the coating's adhesion, toughness, and impact resistance. Formed through a spraying and curing process, the coating exhibits excellent wear resistance and adhesion, making it suitable for surface treatment of various metal products.

[0007] In recent years, the rapid progress of materials science has brought many innovative solutions for the protection of metal tools. Among them, new anti-corrosion coatings such as epoxy resin, polyurethane, and fluorocarbon coatings are gradually becoming important means to protect metal tools from corrosion.

[0008] As a primer coat, epoxy resin shows remarkable effects in preventing the penetration of corrosive media with its excellent adhesion and outstanding chemical resistance. It can closely adhere to the metal surface, forming a strong protective barrier and effectively extending the service life of metal tools. The polyurethane intermediate coat is highly regarded for its excellent abrasion resistance and good elasticity. In occasions with large mechanical wear, the polyurethane coating can show its unique advantages. It can not only effectively resist wear but also maintain the integrity and protective performance of the coating, providing long-term protection for metal tools. The fluorocarbon coating is widely used in outdoor environments due to its excellent weather resistance and UV resistance. It can resist the erosion of natural factors such as sunlight, wind, and rain for a long time, maintaining the smoothness and beauty of the metal tool surface, and at the same time providing a reliable protective barrier for metal tools. The emergence of these new anti-corrosion coatings not only provides more choices for the protection of metal tools but also injects new vitality into the sustainable development of various industries.

[0009] Chinese Patent CN220203961U discloses an anti-slip hair dryer hook. A protection mechanism is provided on the outer surface of the hook body. An anti-slip mechanism is provided on the protection mechanism. The anti-slip mechanism includes a weather-resistant layer. A paste layer is fixed on the outer surface of the weather-resistant layer. An anti-slip layer is fixed on the outer surface of the paste layer. For this anti-slip hair dryer hook, through the anti-slip mechanism composed of a weather-resistant layer, a paste layer, an anti-slip layer, and anti-slip bumps, the weather-resistant layer is epoxy resin, the paste layer is phenolic resin, with an anti-slip layer and anti-slip bumps, which improves the anti-slip performance of the hook body, has a better fixing effect on the hair dryer, and prevents it from sliding. Through the protection mechanism composed of an anti-corrosion layer, a flame-retardant layer, a tensile layer, and a moisture-proof layer, the anti-corrosion layer, the flame-retardant layer is antimony trioxide, the tensile layer is polyester fiber, and the moisture-proof layer is polyethylene film, which improves the protection of the hook body.

[0010] However, although these new coatings have certain advantages in anti-corrosion, there are still some problems in practical applications. For example, a single coating is difficult to simultaneously consider corrosion resistance, abrasion resistance, and adhesion; the process of multi-layer coatings is complex, the interfacial bonding strength between coatings is insufficient, and delamination is likely to occur; in addition, the curing temperature and time of different coating materials are different, which may lead to defects such as cracking and deformation of the coatings. Summary of the Invention

[0011] Aiming at the deficiencies of the existing technology, a multi-layer anti-corrosion coating including a bottom coating, an intermediate coating and a top coating is proposed, and the material formulas, coating processes and curing conditions of each layer of coating are optimized to improve the comprehensive anti-corrosion performance of the coating and extend the service life of metal tools in harsh environments, which has important practical significance and application value.

[0012] To achieve the above object, the technical solution adopted by the present invention is as follows: A preparation method of a strongly wear-resistant anti-corrosion coating for metal tools, characterized by comprising the following steps: Substrate pretreatment: Place the metal tool substrate in a cleaning solution for ultrasonic cleaning to remove the attached oil stains and impurities on the surface; then use sandpaper or sandblasting equipment with a mesh size of 50 to 200 to polish the surface of the metal tool so that the surface roughness reaches Rz10-20 microns to increase the coating adhesion; the surface of the treated metal tool needs to be kept clean without obvious oxide scale and rust. Bottom coating application: Uniformly apply an epoxy resin bottom coating on the surface of the pretreated metal tool. The viscosity of the used epoxy resin is 800-1200 mPa·s, and the thickness of the bottom coating is controlled between 15-25 microns; after the application is completed, cure it in an oven at 150°C for 30 minutes. Intermediate coating application: Apply a polyurethane intermediate coating on the cured bottom coating. The solid content of the used polyurethane coating is 60-70%, and the coating thickness is controlled between 20-30 microns. After the application is completed, cure it in an oven at 120°C for 20 minutes; Top coating application: Apply a fluorocarbon resin top coating on the intermediate coating. The used fluorocarbon resin has weather resistance and chemical corrosion resistance, with a viscosity of 500-700 mPa·s and a solid content of 50-60%; the thickness of the top coating is controlled between 40-50 microns. After the application is completed, cure it in an oven at 180°C for 40 minutes.

[0013] The epoxy resin bottom coating contains 0.5-2% of a coupling agent to enhance the adhesion between the bottom coating and the metal substrate.

[0014] The coupling agent is selected from at least one of γ-aminopropyltriethoxysilane (KH-550), γ-glycidoxypropyltrimethoxysilane (KH-560), and vinyltriethoxysilane (A-151).

[0015] The polyurethane intermediate coating is added with 1-5% of modified nano-silica to enhance the wear resistance and impact resistance of the coating.

[0016] The modification method of the modified nano-silica is as follows: B1: By weight: In a stirring kettle, mix 6 - 10 parts of isocyanatopropyltriethoxysilane, 100 - 150 parts of silica, and 1000 - 1200 parts of toluene by stirring; Reaction conditions: Stir and react at 30 - 40 °C for 40 - 100 minutes; B2: Weigh the raw materials: Weigh 1 - 4 parts of 2,2’,3,3’ - tetrahydroxy - 1,1’ - binaphthalene (CAS: 61601 - 94 - 3), 0.08 - 0.5 parts of dihydroxybis(ammonium lactate)titanium (CAS: 39215 - 21 - 9), and 2 - 6 parts of stannous octoate; Reaction conditions: Stir and react at 80 - 90 °C for 60 - 120 minutes; Post - treatment: Filter and dry to obtain modified nano - silica.

[0017] The fluorocarbon resin top - coat is selected from at least one of polyvinylidene fluoride, polytetrafluoroethylene, or ethylene - tetrafluoroethylene copolymer, and contains 2 - 4% of an ultraviolet absorber to improve the weather resistance and ultraviolet resistance of the coating.

[0018] The ultraviolet absorber is selected from at least one of 2 - (2 - hydroxy - 5 - methylphenyl)benzotriazole, 2 - (2H - benzotriazol - 2 - yl)-4 - methyl - 6 - (2 - methyl - 2 - propyl)phenol, 2,4 - dihydroxyphenyl - 4,6 - diphenyl - 1,3,5 - triazine, 2 - (3',5' - di - tert - butyl - 2' - hydroxyphenyl)-5 - chloro - 2H - benzotriazole.

[0019] The total thickness of the anti - corrosion coating is 50 - 90 microns, where the thickness of the bottom - coat is 15 - 25 microns, the thickness of the intermediate - coat is 20 - 30 microns, and the thickness of the top - coat is 40 - 50 microns; the control accuracy of the total thickness is ±5%.

[0020] The curing temperature of the bottom - coat is 150 °C, and the curing time is 30 - 40 minutes; the curing temperature of the intermediate - coat is 110 - 130 °C, and the curing time is 15 - 25 minutes; the curing temperature of the top - coat is 170 - 190 °C, and the curing time is 35 - 45 minutes; the substrate needs to be cooled to room temperature before each coating.

[0021] The bottom - coat, intermediate - coat, and top - coat are each coated twice, and baked and cured after each coating. The thickness of the second coating should be 70 - 80% of the thickness of the first coating; the surface of the final coating should be smooth and flat, without obvious particles or sagging.

[0022] The mechanism and beneficial effects of the above - mentioned modified nano - silica: Reaction mechanism: 1) Isocyanatopropyltriethoxysilane is used to treat the surface of silica to obtain isocyanatopropyl silica. 2,2’,3,3’-Tetrahydroxy-1,1’-binaphthalene undergoes a condensation reaction with isocyanatopropyl silica; dihydroxybis(ammonium lactate)titanium undergoes a condensation reaction with isocyanatopropyl silica to obtain silica grafted with binaphthalene and bis(ammonium lactate)titanium complex on the surface.

[0023] 2) During the reaction process, isocyanatopropyltriethoxysilane first reacts with the hydroxyl groups on the surface of silica to form isocyanatopropyl silica. Subsequently, 2,2’,3,3’-tetrahydroxy-1,1’-binaphthalene and dihydroxybis(ammonium lactate)titanium respectively undergo condensation reactions with the isocyanate groups of isocyanatopropyl silica to form stable chemical bonds.

[0024] Technical effects: 1) By introducing binaphthalene and bis(ammonium lactate)titanium complex, the modified silica exhibits excellent wear resistance in the intermediate coating of the anti-corrosion polyurethane for metal tools. Experiments show that this composite material significantly improves the mechanical strength and durability of the coating, effectively extends the service life of metal tools, and enhances their corrosion resistance.

[0025] 2) By introducing binaphthalene and bis(ammonium lactate)titanium complex, the modified silica exhibits excellent wear resistance in the intermediate coating of the anti-corrosion polyurethane for metal tools. Experiments show that this composite material significantly improves the mechanical strength and durability of the coating, effectively extends the service life of metal tools, and enhances their corrosion resistance.

[0026] The anti-corrosion coating of the present invention through the multi-layer structure design of the primer, intermediate coating and top coating enables metal tools to have better corrosion resistance in harsh environments, extends the service life of metal tools, and has significant practical value. Detailed implementation manners

[0027] The preferred embodiments of the present invention are elaborated in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0028] Example 1 A method for preparing a strongly wear-resistant anti-corrosion coating for metal tools, characterized by comprising the following steps: Substrate pretreatment: Place the metal tool substrate in a cleaning solution for ultrasonic cleaning to remove the attached oil and impurities on the surface; then use sandpaper with 50 to 200 meshes to polish the surface of the metal tool to make the surface roughness reach Rz 10 microns to increase the coating adhesion; the surface of the treated metal tool should be kept clean without obvious oxide scale and rust. Substrate Coating: Uniformly coat an epoxy resin substrate coating on the surface of the pretreated metal tool. The viscosity of the epoxy resin used is 800 mPa·s, and the thickness of the substrate coating is controlled between 20 microns. After coating, cure it in an oven at 150°C for 30 minutes. Intermediate Coating: Coat a polyurethane intermediate coating on the cured substrate coating. The solid content of the polyurethane coating used is 60%, and it contains nano-silica additives to enhance the wear resistance of the coating. The coating thickness is controlled between 25 microns. After coating, cure it in an oven at 120°C for 20 minutes. Topcoat Coating: Coat a fluorocarbon resin topcoat on the intermediate coating. The fluorocarbon resin used has weather resistance and chemical corrosion resistance, with a viscosity of 500 mPa·s and a solid content of 50%. The topcoat thickness is controlled between 45 microns. After coating, cure it in an oven at 180°C for 40 minutes.

[0029] The epoxy resin substrate coating (DER 331) contains 0.5% coupling agent to enhance the adhesion between the substrate coating and the metal substrate.

[0030] The coupling agent is selected from γ-aminopropyltriethoxysilane (KH-550).

[0031] The polyurethane intermediate coating (Desmophen 1150 BT) is added with 1% modified nano-silica to enhance the wear resistance and impact resistance of the coating.

[0032] The modification method of the modified nano-silica is as follows: B1: In a stirring kettle, stir and mix 6g of isocyanatopropyltriethoxysilane, 100g of silica, and 1000g of toluene. Reaction conditions: Stir and react at 30°C for 40 minutes. B2: Weigh the raw materials: Weigh 1g of 2,2’,3,3’-tetrahydroxy-1,1’-binaphthalene (CAS: 61601-94-3), 0.08g of dihydroxybis(lactato)titanium(IV) (CAS: 39215-21-9), and 2g of stannous octoate. Reaction conditions: Stir and react at 80°C for 60 minutes. Post-treatment: Filter and dry to obtain the modified nano-silica.

[0033] The fluorocarbon resin topcoat is selected from polyvinylidene fluoride and contains 2% ultraviolet absorber to improve the weather resistance and ultraviolet resistance of the coating.

[0034] The ultraviolet absorber is selected from 2-(2-hydroxy-5-methylphenyl)benzotriazole.

[0035] The total thickness of the coating is 90 microns, where the thickness of the bottom coat is 20 microns, the thickness of the intermediate coat is 25 microns, and the thickness of the top coat is 45 microns; the control accuracy of the total thickness is ±5%.

[0036] The curing temperature of the bottom coat is 150 °C and the curing time is 30 minutes; the curing temperature of the intermediate coat is 110 °C and the curing time is 25 minutes; the curing temperature of the top coat is 170 °C and the curing time is 45 minutes; the substrate needs to be cooled to room temperature before each coating application.

[0037] The bottom coat, intermediate coat, and top coat are each coated twice. After each coating, baking and curing are carried out. The thickness of the second coating should be 70% of the thickness of the first coating; the surface of the final coating should be smooth and flat, without obvious particles or sagging.

[0038] Example 2 A method for preparing a strongly wear-resistant and anti-corrosion coating for metal tools, characterized by comprising the following steps: Substrate pretreatment: Place the metal tool substrate in a cleaning solution for ultrasonic cleaning to remove the attached oil and impurities on the surface; then use sandpaper with a mesh size of 50 to 200 to polish the surface of the metal tool so that the surface roughness reaches Rz 15 microns to increase the coating adhesion; the surface of the treated metal tool needs to be kept clean, without obvious scale and rust. Bottom coat application: Uniformly apply an epoxy resin bottom coat on the surface of the pretreated metal tool. The viscosity of the used epoxy resin is 1000 mPa·s, and the thickness of the bottom coat is controlled between 20 microns; after application, cure in an oven at 150 °C for 30 minutes. Intermediate coat application: Apply a polyurethane intermediate coat on the cured bottom coat. The solid content of the used polyurethane coating is 65% and contains nano-silica additives to enhance the wear resistance of the coating; the coating thickness is controlled between 25 microns. After application, cure in an oven at 120 °C for 20 minutes. Top coat application: Apply a fluorocarbon resin top coat on the intermediate coat. The used fluorocarbon resin has weather resistance and chemical corrosion resistance, with a viscosity of 600 mPa·s and a solid content of 55%; the top coat thickness is controlled between 45 microns. After application, cure in an oven at 180 °C for 40 minutes.

[0039] The epoxy resin bottom coat (DER 331) contains 1% of a coupling agent to enhance the adhesion between the bottom coat and the metal substrate.

[0040] The coupling agent is selected from γ-glycidoxypropyltrimethoxysilane (KH-560).

[0041] The polyurethane intermediate coating (Desmophen 1150 BT) is added with 2% of modified nano-silica to enhance the wear resistance and impact resistance of the coating.

[0042] The modification method of the modified nano-silica is as follows: B1: In a stirring kettle, 8 g of isocyanatopropyltriethoxysilane, 125 g of silica and 1100 g of toluene are stirred and mixed. Reaction conditions: Stir and react at 35 °C for 60 minutes. B2: Weigh the raw materials: Weigh 2.5 g of 2,2’,3,3’-tetrahydroxy-1,1’-binaphthalene (CAS: 61601-94-3), 0.2 g of dihydroxybis(lactate ammonium) titanium (CAS: 39215-21-9) and 4 g of stannous octoate. Reaction conditions: Stir and react at 85 °C for 80 minutes. Post-treatment: Filter and dry to obtain the modified nano-silica.

[0043] The fluorocarbon resin top coating is selected from polytetrafluoroethylene and contains 3% of ultraviolet absorber to improve the weather resistance and ultraviolet resistance of the coating.

[0044] The ultraviolet absorber is selected from 2-(2H-benzotriazol-2-yl)-4-methyl-6-(2-methyl-2-propyl)phenol.

[0045] The total thickness of the coating is 90 microns, where the thickness of the bottom coating is 20 microns, the thickness of the intermediate coating is 25 microns, and the thickness of the top coating is 45 microns; the control accuracy of the total thickness is ±5%.

[0046] The curing temperature of the bottom coating is 150 °C and the curing time is 35 minutes; the curing temperature of the intermediate coating is 120 °C and the curing time is 20 minutes; the curing temperature of the top coating is 180 °C and the curing time is 40 minutes; the substrate needs to be cooled to room temperature before each layer is coated.

[0047] The bottom coating, intermediate coating and top coating are respectively coated twice, and baking and curing are carried out after each coating. The thickness of the second coating should be 75% of the thickness of the first coating; the surface of the final coating should be smooth and flat without obvious particles or sagging phenomena.

[0048] Example 3 A preparation method of a strongly wear-resistant and anti-corrosion coating for metal tools, characterized by comprising the following steps: Substrate Pretreatment: Place the metal tool substrate in a cleaning solution for ultrasonic cleaning to remove the oil and impurities adhering to the surface; then use sandpaper with a mesh size of 50 to 200 to polish the surface of the metal tool so that the surface roughness reaches Rz 15 microns to increase the coating adhesion; the surface of the treated metal tool should be kept clean, without obvious scale and rust; Primer Coating Application: Uniformly apply an epoxy resin primer coating on the surface of the pretreated metal tool. The viscosity of the epoxy resin used is 1000 mPa·s, and the primer coating thickness is controlled within 20 microns; after coating, cure it in an oven at 150 °C for 30 minutes; Intermediate Coating Application: Apply a polyurethane intermediate coating on the cured primer coating. The solid content of the polyurethane coating used is 65%, and it contains nano-silica additives to enhance the coating wear resistance; the coating thickness is controlled within 25 microns. After coating, cure it in an oven at 120 °C for 20 minutes; Top Coating Application: Apply a fluorocarbon resin top coating on the intermediate coating. The fluorocarbon resin used has weather resistance and chemical corrosion resistance, with a viscosity of 600 mPa·s and a solid content of 55%; the top coating thickness is controlled within 45 microns. After coating, cure it in an oven at 180 °C for 40 minutes.

[0049] The epoxy resin primer coating (DER 331) contains 1.5% coupling agent to enhance the adhesion between the primer coating and the metal substrate.

[0050] The coupling agent is selected from γ-glycidoxypropyltrimethoxysilane (KH-560).

[0051] The polyurethane intermediate coating (Desmophen 1150 BT) is added with 4% modified nano-silica to enhance the wear resistance and impact resistance of the coating.

[0052] The modification method of the modified nano-silica is as follows: B1: In a stirring kettle, stir and mix 8 g of isocyanatopropyltriethoxysilane, 140 g of silica, and 1100 g of toluene; Reaction conditions: Stir and react at 35 °C for 80 minutes; B2: Weigh the raw materials: Weigh 3 g of 2,2’,3,3’-tetrahydroxy-1,1’-binaphthalene (CAS: 61601-94-3), 0.4 g of dihydroxybis(lactate ammonium)titanium (CAS: 39215-21-9), and 5 g of stannous octoate; Reaction conditions: Stir and react at 85 °C for 100 minutes; Post-treatment: Filter and dry to obtain the modified nano-silica.

[0053] The fluorocarbon resin topcoat is selected from polytetrafluoroethylene and contains 3% ultraviolet absorber to improve the weather resistance and ultraviolet resistance of the coating.

[0054] The ultraviolet absorber is selected from 2,4-dihydroxyphenyl-4,6-diphenyl-1,3,5-triazine.

[0055] The total thickness of the coating is 90 microns, where the thickness of the primer coat is 20 microns, the thickness of the intermediate coat is 25 microns, and the thickness of the topcoat is 45 microns; the control accuracy of the total thickness is ±5%.

[0056] The curing temperature of the primer coat is 150 °C and the curing time is 35 minutes; the curing temperature of the intermediate coat is 120 °C and the curing time is 20 minutes; the curing temperature of the topcoat is 180 °C and the curing time is 40 minutes; the substrate needs to be cooled to room temperature before each layer is coated.

[0057] The primer coat, intermediate coat, and topcoat are each coated twice, and baking and curing are carried out after each coating. The thickness of the second coating should be 75% of the thickness of the first coating; the surface of the final coating should be smooth and flat, without obvious particles or sagging.

[0058] Example 4 A method for preparing a strongly wear-resistant and anti-corrosion coating for metal tools, characterized by comprising the following steps: Substrate pretreatment: Place the metal tool substrate in a cleaning solution for ultrasonic cleaning to remove the oil stains and impurities attached to the surface; then use sandpaper with a mesh size of 50 to 200 to polish the surface of the metal tool so that the surface roughness reaches Rz 20 microns to increase the coating adhesion; the surface of the treated metal tool needs to be kept clean, without obvious oxide scale and rust. Primer coat coating: Uniformly coat an epoxy resin primer coat on the surface of the pretreated metal tool. The viscosity of the used epoxy resin is 1200 mPa·s, and the thickness of the primer coat is controlled between 25 microns; after coating, cure it in an oven at 150 °C for 30 minutes. Intermediate coat coating: Coat a polyurethane intermediate coat on the cured primer coat. The solid content of the used polyurethane coating is 70% and contains nano-silica additives to enhance the wear resistance of the coating; the coating thickness is controlled between 30 microns. After coating, cure it in an oven at 120 °C for 20 minutes. Topcoat coating: Coat a fluorocarbon resin topcoat on the intermediate coat. The used fluorocarbon resin has weather resistance and chemical corrosion resistance, with a viscosity of 700 mPa·s and a solid content of 60%; the thickness of the topcoat is controlled between 50 microns. After coating, cure it in an oven at 180 °C for 40 minutes.

[0059] The epoxy resin primer coat (DER 331) contains 2% coupling agent, which enhances the adhesion between the primer coat and the metal substrate.

[0060] The coupling agent is selected from vinyltriethoxysilane (A-151).

[0061] The polyurethane intermediate coat (Desmophen 1150 BT) is added with 5% modified nano-silica to enhance the abrasion resistance and impact resistance of the coat.

[0062] The modification method of the modified nano-silica is as follows: B1: In a stirring kettle, 10 g of isocyanatopropyltriethoxysilane, 150 g of silica, and 1200 g of toluene are stirred and mixed; Reaction conditions: Stir and react at 40 °C for 100 minutes; B2: Weigh the raw materials: Weigh 4 g of 2,2’,3,3’-tetrahydroxy-1,1’-binaphthalene (CAS: 61601-94-3), 0.5 g of dihydroxybis(ammonium lactate)titanium (CAS: 39215-21-9), and 6 g of stannous octoate; Reaction conditions: Stir and react at 90 °C for 120 minutes; Post-treatment: Filter and dry to obtain the modified nano-silica.

[0063] The fluorocarbon resin top coat is selected from ethylene-tetrafluoroethylene copolymer and contains 4% ultraviolet absorber to improve the weather resistance and ultraviolet resistance of the coat.

[0064] The ultraviolet absorber is selected from 2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chloro-2H-benzotriazole.

[0065] The total thickness of the coat is 90 microns, where the thickness of the primer coat is 20 microns, the thickness of the intermediate coat is 25 microns, and the thickness of the top coat is 45 microns; the control accuracy of the total thickness is ±5%.

[0066] The curing temperature of the primer coat is 150 °C and the curing time is 40 minutes; the curing temperature of the intermediate coat is 130 °C and the curing time is 15 minutes; the curing temperature of the top coat is 190 °C and the curing time is 35 minutes; the substrate needs to be cooled to room temperature before each layer is coated.

[0067] The primer coat, intermediate coat, and top coat are respectively coated twice. After each coating, baking and curing are carried out. The thickness of the second coating should be 80% of the thickness of the first coating; the surface of the final coat should be smooth and flat without obvious particles or sagging.

[0068] Comparative Example 1 The difference from Example 1 is that in Comparative Example 1, 1% of nano-silica is added to the polyurethane intermediate coating (Desmophen 1150 BT) without modification.

[0069] Comparative Example 2 The difference from Example 1 is that in Comparative Example 2, 2,2’,3,3’-tetrahydroxy-1,1’-binaphthalene is not added during the modification of nano-silica.

[0070] Comparative Example 3 The difference from Example 1 is that in Comparative Example 3, dihydroxybis(ammonium lactate)titanium is not added during the modification of nano-silica.

[0071] For the anti-corrosion effect and wear resistance of the coatings prepared in the above examples and comparative examples, the following tests were carried out, and the test results are recorded in Table 1: 1. Salt spray test Test conditions: Salt spray corrosion test was carried out in 5% NaCl solution for 1000 hours.

[0072] 2. Abrasion resistance test Test method: Using a Taber abrasion tester, with CS-10 grinding wheels and a 1000 g load, record the number of revolutions required to wear through the coating until it is exposed.

[0073] 3. Chemical corrosion resistance test Test conditions: The samples were immersed in 10% HCl solution and 10% NaOH solution for 24 hours for each solution.

[0074] Table 1 Salt spray test (1000h) Abrasion resistance test (number of revolutions) Chemical corrosion resistance test (HCl) Chemical corrosion resistance test (NaOH) Example 1 No rust, no blistering 3150 No obvious change No obvious change Example 2 No rust, no blistering 3202 No obvious change No obvious change Example 3 No rust, no blistering 3250 No obvious change No obvious change Example 4 No rust, no blistering 3315 No obvious change No obvious change Comparative example 1 Rust area 13% 1950 Coating blistering Coating peeling Comparative example 2 Rust area about 5% 2575 Slight coating peeling Coating swelling Comparative example 3 Rust area about 4% 2650 Coating blistering Slight coating swelling The test results show that the multi-layer coating structure of the examples significantly enhances the anti-corrosion, wear resistance and chemical corrosion resistance of metal tools in harsh environments, verifying the technical effects of the present invention. The comparative example experiments further corroborate the key role of the combination of the bottom coating, intermediate coating and top coating in improving the durability of the coating.

[0075] The above are only the embodiments of the present invention. Common knowledge such as specific materials and characteristics known in the art is not described in detail here. It should be noted that for those skilled in the art, without departing from the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicality of the patent. The protection scope required by this application should be subject to the content of its claims, and the specific implementation manners and the like recorded in the specification can be used to interpret the content of the claims.

Claims

1. A preparation method of a strong wear-resistant and anti-corrosion coating for metal tools, characterized in that, It includes the following steps: Substrate pretreatment: Place the metal tool substrate in a cleaning solution for ultrasonic cleaning to remove the attached oil and impurities on the surface; then use sandpaper with a mesh size of 50 to 200 or a sandblasting device to polish the surface of the metal tool, so that the surface roughness reaches Rz 10 - 20 microns to increase the coating adhesion; the surface of the treated metal tool should be kept clean without obvious scale and rust. Primer coating: Uniformly coat an epoxy resin primer on the surface of the pretreated metal tool. The viscosity of the used epoxy resin is 800 - 1200 mPa·s, and the thickness of the primer coating is controlled between 15 - 25 microns; after coating, cure it in an oven at 150 °C for 30 minutes. Intermediate coating: Coat a polyurethane intermediate coating on the cured primer coating. The solid content of the used polyurethane coating is 60 - 70%, and the coating thickness is controlled between 20 - 30 microns. After coating, cure it in an oven at 120 °C for 20 minutes; Topcoat coating: Coat a fluorocarbon resin topcoat on the intermediate coating. The used fluorocarbon resin has weather resistance and chemical corrosion resistance, with a viscosity of 500 - 700 mPa·s and a solid content of 50 - 60%; the thickness of the topcoat is controlled between 40 - 50 microns. After coating, cure it in an oven at 180 °C for 40 minutes. 1 - 5% of modified nano - silica is added to the polyurethane intermediate coating. The modified nano - silica is prepared by reacting isocyanatopropyltriethoxysilane, silica, 2,2’,3,3’ - tetrahydroxy - 1,1’ - binaphthalene, and dihydroxybis(lactate ammonium)titanium.

2. The preparation method of a strong wear-resistant and anti-corrosion coating for metal tools according to claim 1, characterized in that: The epoxy resin primer contains 0.5 - 2% of a coupling agent to enhance the adhesion between the primer coating and the metal substrate.

3. The preparation method of a strong wear-resistant and anti-corrosion coating for metal tools according to claim 2, characterized in that: The coupling agent is selected from at least one of γ - aminopropyltriethoxysilane (KH - 550), γ - glycidoxypropyltrimethoxysilane (KH - 560), and vinyltriethoxysilane (A - 151).

4. The preparation method of a strong wear-resistant and anti-corrosion coating for a metal tool according to claim 1, characterized in that: 1 - 5% of modified nano - silica is added to the polyurethane intermediate coating to enhance the wear resistance and impact resistance of the coating.

5. The preparation method of a strong wear-resistant and anti-corrosion coating for metal tools according to claim 4, characterized in that: The modification method of the modified nano - silica is as follows: B1: By weight: In a stirring kettle, stir - mix 6 - 10 parts of isocyanatopropyltriethoxysilane, 100 - 150 parts of silica, and 1000 - 1200 parts of toluene. Reaction conditions: Stir - react at 30 - 40 °C for 40 - 100 minutes. B2: Weigh the raw materials: Weigh 1 - 4 parts of 2,2’,3,3’ - tetrahydroxy - 1,1’ - binaphthalene, 0.08 - 0.5 part of dihydroxybis(lactate ammonium)titanium, and 2 - 6 parts of stannous octoate. Reaction conditions: Stir - react at 80 - 90 °C for 60 - 120 minutes. Post - treatment: Filter and dry to obtain the modified nano - silica.

6. The preparation method of a strongly wear-resistant and anti-corrosion coating for a metal tool according to claim 1, characterized in that: The fluorocarbon resin topcoat is selected from at least one of polyvinylidene fluoride, polytetrafluoroethylene, or ethylene - tetrafluoroethylene copolymer, and contains 2 - 4% of an ultraviolet absorber to improve the weather resistance and ultraviolet resistance of the coating.

7. The preparation method of a strong wear-resistant and anti-corrosion coating for metal tools according to claim 6, characterized in that: The ultraviolet absorber is selected from at least one of 2-(2-hydroxy-5-methylphenyl) benzotriazole, 2-(2H-benzotriazol-2-yl)-4-methyl-6-(2-methyl-2-propyl) phenol, 2,4-dihydroxyphenyl-4,6-diphenyl-1,3,5-triazine, and 2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chloro-2H-benzotriazole.

8. The preparation method of a strongly wear-resistant and anti-corrosion coating for a metal tool according to claim 1, characterized in that: The total thickness of the anticorrosive coating is 50-90 microns, where the thickness of the bottom coating is 15-25 microns, the thickness of the intermediate coating is 20-30 microns, and the thickness of the top coating is 40-50 microns; the control accuracy of the total thickness is ±5%.

9. The preparation method of a strong wear-resistant and anti-corrosion coating for a metal tool according to claim 1, characterized in that: The curing temperature of the bottom coating is 150 °C and the curing time is 30-40 minutes; the curing temperature of the intermediate coating is 110-130 °C and the curing time is 15-25 minutes; the curing temperature of the top coating is 170-190 °C and the curing time is 35-45 minutes; the substrate needs to be cooled to room temperature before each coating.

10. The preparation method of a strongly wear-resistant and anti-corrosion coating for metal tools according to claim 1, characterized in that: The bottom coating, intermediate coating, and top coating are each coated twice, and baking and curing are carried out after each coating; the thickness of the second coating should be 70-80% of the thickness of the first coating; the surface of the final coating should be smooth and flat, without obvious particles or sagging.