Anti-corrosion coating applied to steel structure and preparation method of anti-corrosion coating

Abstract

The invention belongs to the technical field of coatings, and particularly relates to an anticorrosive coating applied to a steel structure and a preparation method thereof. The anticorrosive paint applied to the steel structure comprises the following components in parts by weight: 20-40 parts of nano metal oxide modified epoxy resin emulsion; 20 to 40 parts of castor oil based polyurethane emulsion; 15 to 30 parts of fluorocarbon resin emulsion; 1-5 parts of a silane coupling agent; 2-10 parts of a graphene modified metal organic framework; 0.3-1 part of a water-based inorganic adhesive; 2-5 parts of a filler; and 20 parts of deionized water. The preparation method comprises the following steps: preparing the nano metal oxide modified epoxy resin emulsion, preparing the castor oil-based polyurethane, preparing the coating base material, preparing the auxiliary material and preparing the anticorrosive coating. According to the anticorrosive paint applied to the steel structure, the adhesive force between the paint and the surface of the steel structure is effectively solved, meanwhile, the surface and the internal structure of a coating formed by the paint have good hydrophobicity and chemical inertness, and the anticorrosive performance is excellent.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and in particular relates to an anti-corrosion coating applied to steel structures and a preparation method thereof. Background Art

[0002] With the continuous development of my country's economy, infrastructure construction is also rapidly updating. Steel structures are widely used in the construction field, bridge engineering, industry and public facilities due to their high strength, light weight and good construction performance.

[0003] In practical applications, steel structures in the construction field and bridge engineering are exposed to the outdoors for a long time, or are in high temperature, high humidity, and high load conditions. Due to the thermal expansion and contraction and vibration of the steel structure itself, steel structure projects are prone to rust and corrosion. This puts higher requirements on the anti-corrosion coatings used in steel structures.

[0004] Water-based paints are non-toxic, odorless, safe, reliable, easy to construct, and cost-effective, and are widely used. Chinese invention patent CN 118599376 A discloses a waterproof protective coating for steel structures, which uses polymer emulsion and cement as the main base materials, and achieves a single-layer coating that meets the primer, mid-coat, and topcoat indicators of anti-corrosion coatings, simplifying the protection process. However, this type of coating relies on the acrylic side chain structure in the polymer emulsion to firmly bind the steel structure and the coating layer, and its stability needs to be improved. Chinese invention patent CN 119220152 A discloses a waterproof coating for steel structure roofs, which uses epoxy resin and acrylic acid as the main base materials, and cross-links the base material structure through various additives, but its anti-corrosion performance is only prevented by silica fillers, and its anti-corrosion performance needs to be improved. Summary of the invention

[0005] The technical problem to be solved by the present invention is: In view of the above-mentioned defects, the present invention provides an anti-corrosion coating for steel structures and a preparation method thereof, which effectively solves the adhesion problem between the coating and the surface of the steel structure. At the same time, the coating surface and internal structure formed by the coating have good hydrophobicity and chemical inertness, and excellent anti-corrosion performance.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows: the anti-corrosion coating applied to the steel structure comprises the following components by weight: 20-40 parts of nano metal oxide modified epoxy resin emulsion; 20-40 parts of castor oil-based polyurethane emulsion; 15-30 parts of fluorocarbon resin emulsion; 1-5 parts of silane coupling agent; 2-10 parts of graphene modified metal organic framework; 0.3-1 parts of water-based inorganic adhesive; 2-5 parts of filler; and 20 parts of deionized water.

[0007] Furthermore, the metal oxide in the nano-metal oxide modified epoxy resin emulsion is CrO2, TiO2, ZrO2 or SiO2.

[0008] Furthermore, the silane coupling agent is a silane coupling agent prepared by mixing isobutyltriethoxysilane and bisaminosilane coupling agent in a mass ratio of 1:0.5.

[0009] Furthermore, the aqueous inorganic adhesive is one or more of a sodium silicate-based adhesive and a copper oxide phosphate adhesive.

[0010] Furthermore, the filler is one or more of calcium carbonate, attapulgite, and graphene.

[0011] The preparation method of the anticorrosive coating applied to the steel structure comprises the following steps: Step S1, preparation of nano-metal oxide modified epoxy resin emulsion: adding nano-metal oxide and diphenylmethane diisocyanate into a reaction container, reacting at 80°C-90°C for 30min-1h, adding epoxy resin, keeping the temperature for 2h, cooling and degassing, and obtaining nano-metal oxide modified epoxy resin emulsion; Step S2, preparation of castor oil-based polyurethane, drying and dehydrating castor oil at 80° C. for pretreatment, weighing a calculated amount of castor oil and polyethylene glycol monomethyl ether, using acetone as a solvent, adding diisophorone diisocyanate and reacting for 2-5 hours at a reaction temperature of 65-75° C.; after cooling, adding deionized water and stirring to emulsify, rotating the emulsion to remove the solvent to obtain castor oil-based polyurethane; Step S3, preparation of a coating substrate, adding a calculated amount of castor oil polyurethane emulsion, the prepared nano metal oxide modified epoxy resin emulsion, and fluorocarbon resin into a reaction container, adding half of deionized water, and mixing evenly to form a coating substrate; Step S4, preparation of auxiliary materials, dispersing the silane coupling agent, the graphene-modified metal organic framework, and the filler in the remaining deionized water to form auxiliary materials for coatings; Step S5, mixing the coating base material and auxiliary materials obtained in steps S3 and S4, adding a water-based inorganic adhesive, and mixing evenly to obtain an anti-corrosion coating for steel structures.

[0012] Furthermore, the molar ratio of the nano metal oxide to diphenylmethane diisocyanate is 1:(0.1-0.4).

[0013] Furthermore, the mass ratio between castor oil groups and polyethylene glycol monomethyl ether in the castor oil-based polyurethane is (0.25-4):1.

[0014] Furthermore, the preparation method of the graphene-modified metal-organic framework comprises adding graphene and sodium bicarbonate to a DMF solution, stirring for 1 hour, filtering and drying; adding the filter cake and the metal-organic framework to an ethanol-water solution, stirring for 1-3 hours at reflux temperature, and drying after the reaction to obtain the graphene-modified metal-organic framework.

[0015] Furthermore, the weight ratio of the graphene to the metal organic framework is (0.6-3):1.

[0016] The beneficial effects of the present invention are: 1. Epoxy resin-polyurethane-fluorocarbon resin system. A semi-interpenetrating polymer network and an interpenetrating network structure are formed between epoxy resin and polyurethane. The fluorocarbon resin has hydroxyl groups on its side chains. When in contact with epoxy resin, the epoxy functional groups open and react with the hydroxyl groups on the fluorocarbon resin to form a cross-linked network. The graphene ends in the graphene-modified metal organic framework are doped into the network structure to improve the toughness and rigidity of the coating. The metal organic framework itself acts as an adhesive. The silane coupling agent can make up for the permeability and water repellency of the resin system. A small amount of water-based inorganic adhesive can further improve the affinity and bonding performance of the coating in contact with the steel structure surface. A small amount of filler is dispersed in the coating to further improve the anti-corrosion performance of the coating.

[0017] 2. Nano-metal oxides are used to modify epoxy resin. Nano-materials have small pores and can fill the holes in the epoxy coating, forming a maze effect, effectively preventing the penetration of corrosive media, significantly improving the corrosion resistance of the coating, and increasing the fluidity of the coating, reducing the formation of bubbles and defects, increasing the density of the coating, and reducing the use of additives.

[0018] 3. Use castor oil to partially replace polyether polyol to synthesize polyurethane coating, improve the cross-linking degree of polyurethane, and make it have better heat resistance and mechanical properties. When using this kind of polyurethane, the contact angle between the coating and the surface of the steel structure is reduced, and it has good affinity with the surface of the steel structure.

[0019] 4. The silane coupling agent is a mixture of isobutyltriethoxysilane and bisaminosilane coupling agent. It can form a silane film that penetrates the coating in the coating. When coating, it can reduce the pretreatment of the steel structure surface and simplify the coating process. This silane coupling agent can also enhance the adhesion and corrosion resistance of the coating system.

[0020] 5. In the preparation process of anti-corrosion coatings, adding water-based inorganic adhesives in the last step can avoid the coating from agglomerating and curing, and the coating can be stored for a long time. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] Example 1 The anti-corrosion coating applied to steel structure comprises the following components by weight: 25 parts of nano-CrO2 modified epoxy resin emulsion, 40 parts of castor oil-based polyurethane emulsion, 15 parts of fluorocarbon resin emulsion, 2 parts of silane coupling agent prepared by mixing isobutyltriethoxysilane and bisaminosilane coupling agent in a mass ratio of 1:0.5, 2 parts of graphene modified metal organic framework, 0.3 parts of sodium silicate-based binder, 3 parts of mixed filler prepared by mixing calcium carbonate and attapulgite in a mass ratio of 1:1, and 20 parts of deionized water.

[0023] The method for preparing the anticorrosive coating applied to steel structures comprises the following steps: Step S1, preparation of nano-CrO2 modified epoxy resin emulsion: add 3.5g nano-CrO2 and 10g diphenylmethane diisocyanate into a reaction container, react at 80°C-90°C for 30min-1h, add 100g epoxy resin, keep the temperature for 2h, cool down and degas, and obtain nano-CrO2 modified epoxy resin emulsion; Step S2, preparation of castor oil-based polyurethane, drying and dehydrating castor oil at 80°C for pretreatment, weighing 6g of castor oil and 24g of polyethylene glycol monomethyl ether, adding 100mL of acetone as solvent, adding 44g of diisophorone diisocyanate and 47.5g of 2,2-bis(hydroxymethyl)propionic acid, and reacting for 2-5h, the reaction temperature is controlled at 65-75°C; after cooling, adding deionized water, stirring and emulsifying, and rotating the emulsion to remove the solvent to obtain castor oil-based polyurethane; Step S3, preparing a coating substrate, weighing the castor oil polyurethane emulsion, the nano metal oxide modified epoxy resin emulsion, and the fluorocarbon resin prepared above according to the weight parts, adding them into a reaction container, adding half of the deionized water, and mixing them evenly to form a coating substrate; Step S40, preparation of graphene-modified metal organic framework, adding 60g of graphene and 8.4g of sodium bicarbonate to 100mL of DMF solution, stirring for 1h, filtering and drying; adding the filter cake and 100g of metal organic framework to ethanol-water solution, stirring at reflux temperature for 1-3h, and drying after the reaction to obtain the graphene-modified metal organic framework; Step S4, preparation of auxiliary materials, dispersing a silane coupling agent prepared by mixing a bisaminosilane coupling agent in a mass ratio of 1:0.5, a graphene-modified metal organic framework, calcium carbonate and attapulgite in a mass ratio of 1:1 into the remaining deionized water to form an auxiliary material for coating; Step S5, mixing the coating base material and auxiliary materials obtained in steps S3 and S4, adding a sodium silicate-based binder, and mixing evenly to obtain an anti-corrosion coating for steel structures.

[0024] Example 2 The anti-corrosion coating applied to steel structure comprises the following components by weight: 40 parts of nano-TiO2 modified epoxy resin emulsion, 20 parts of castor oil-based polyurethane emulsion, 30 parts of fluorocarbon resin emulsion, 5 parts of silane coupling agent prepared by mixing isobutyltriethoxysilane and bisaminosilane coupling agent in a mass ratio of 1:0.5, 5 parts of graphene modified metal organic framework, 0.5 parts of copper oxide phosphate adhesive, 2 parts of graphene and 20 parts of deionized water.

[0025] The method for preparing the anticorrosive coating applied to steel structures comprises the following steps: Step S1, preparation of nano-TiO2 modified epoxy resin emulsion: add 16g nano-TiO2 and 10g diphenylmethane diisocyanate into a reaction container, react at 80°C-90°C for 30min-1h, add 100g epoxy resin, keep the temperature for 2h, cool and degas, and obtain nano-TiO2 modified epoxy resin emulsion; Step S2, preparation of castor oil-based polyurethane, drying and dehydrating castor oil at 80°C for pretreatment, weighing 12g castor oil and 18g polyethylene glycol monomethyl ether, adding 100mL acetone as solvent, adding 44g diisophorone diisocyanate and 47.5g 2,2-bis(hydroxymethyl)propionic acid, and reacting for 2-5h, the reaction temperature is controlled at 65-75°C; after cooling, adding deionized water, stirring and emulsifying, and rotating the emulsion to remove the solvent to obtain castor oil-based polyurethane; Step S3, preparation of a coating substrate, adding a calculated amount of castor oil polyurethane emulsion, the prepared nano metal oxide modified epoxy resin emulsion, and fluorocarbon resin into a reaction container, adding half of deionized water, and mixing evenly to form a coating substrate; Step S40, preparation of graphene-modified metal organic framework, adding 100g of graphene and 8.4g of sodium bicarbonate to 250mL of DMF solution, stirring for 1h, filtering and drying; adding the filter cake and 100g of metal organic framework to ethanol-water solution, stirring at reflux temperature for 1-3h, and drying after the reaction to obtain the graphene-modified metal organic framework; Step S4, preparation of auxiliary materials, dispersing the silane coupling agent, the graphene-modified metal organic framework, and the graphene prepared by mixing the bisaminosilane coupling agent in a mass ratio of 1:0.5 in the remaining deionized water to form an auxiliary material for coating; Step S5, mixing the coating base material and auxiliary materials obtained in steps S3 and S4, adding copper oxide phosphate adhesive, and mixing evenly to obtain an anti-corrosion coating for steel structures.

[0026] Example 3 The anti-corrosion coating applied to steel structure comprises the following components by weight: 20 parts of nano ZrO2 modified epoxy resin emulsion, 40 parts of castor oil-based polyurethane emulsion, 20 parts of fluorocarbon resin emulsion, 1 part of silane coupling agent prepared by mixing isobutyl triethoxy silane and bisamino silane coupling agent in a mass ratio of 1:0.5, 10 parts of graphene modified metal organic framework, 1 part of adhesive prepared by mixing sodium silicate-based adhesive and copper oxide phosphate adhesive in a mass ratio of 1:1, 5 parts of calcium carbonate and 20 parts of deionized water.

[0027] The method for preparing the anticorrosive coating applied to steel structures comprises the following steps: Step S1, preparation of nano ZrO2 modified epoxy resin emulsion: add 24.6g nano ZrO2 and 20g diphenylmethane diisocyanate into a reaction container, react at 80℃-90℃ for 30min-1h, add 100g epoxy resin, keep the temperature for 2h, cool down and degas to obtain nano ZrO2 modified epoxy resin emulsion; Step S2, preparation of castor oil-based polyurethane, drying and dehydrating castor oil at 80°C for pretreatment, drying and dehydrating castor oil at 80°C for pretreatment, weighing 18g castor oil and 12g polyethylene glycol monomethyl ether, adding 100mL acetone as solvent, adding 44g diisophorone diisocyanate and 47.5g 2,2-bis(hydroxymethyl)propionic acid and reacting for 2-5h, the reaction temperature is controlled at 65-75°C; after cooling, adding deionized water and stirring to emulsify, rotating the emulsion to remove the solvent to obtain castor oil-based polyurethane; Step S3, preparation of a coating substrate, adding a calculated amount of castor oil polyurethane emulsion, the prepared nano metal oxide modified epoxy resin emulsion, and fluorocarbon resin into a reaction container, adding half of deionized water, and mixing evenly to form a coating substrate; Step S40, preparation of graphene-modified metal organic framework, adding 300g of graphene and 25.2g of sodium bicarbonate to 500mL of DMF solution, stirring for 1h, filtering and drying; adding the filter cake and 100g of metal organic framework to ethanol-water solution, stirring at reflux temperature for 1-3h, and drying after the reaction to obtain the graphene-modified metal organic framework; Step S4, preparation of auxiliary materials, dispersing a silane coupling agent prepared by mixing isobutyltriethoxysilane and a bisaminosilane coupling agent in a mass ratio of 1:0.5, a graphene-modified metal organic framework, and calcium carbonate in the remaining deionized water to form an auxiliary material for coating; Step S5, mixing the coating base material and auxiliary materials obtained in steps S3 and S4, adding an adhesive prepared by mixing a sodium acid-based binder and a copper oxide phosphate adhesive in a mass ratio of 1:1, and mixing evenly to obtain an anticorrosive coating for steel structures.

[0028] Example 4 The anti-corrosion coating applied to steel structures includes the following components by weight: 32 parts of nano-SiO2 modified epoxy resin emulsion, 32 parts of castor oil-based polyurethane emulsion, 24 parts of fluorocarbon resin emulsion, 3 parts of silane coupling agent prepared by mixing isobutyltriethoxysilane and bisaminosilane coupling agent in a mass ratio of 1:0.5, 6 parts of graphene modified metal organic framework, 0.8 parts of sodium silicate-based binder, 2 parts of graphene, and 20 parts of deionized water.

[0029] The method for preparing the anticorrosive coating applied to steel structures comprises the following steps: Step S1, preparation of nano-metal oxide modified epoxy resin emulsion: add 12g nano-SiO2 and 15g diphenylmethane diisocyanate into a reaction container, react at 80°C-90°C for 30min-1h, add epoxy resin, keep the temperature for 2h, cool and degas, and obtain nano-SiO2 modified epoxy resin emulsion; Step S2, preparation of castor oil-based polyurethane, drying and dehydrating castor oil at 80°C for pretreatment, weighing 24g of castor oil and 8g of polyethylene glycol monomethyl ether, adding 100mL of acetone as solvent, adding 44g of diisophorone diisocyanate and 47.5g of 2,2-bis(hydroxymethyl)propionic acid, and reacting for 2-5h, the reaction temperature is controlled at 65-75°C; after cooling, adding deionized water, stirring and emulsifying, and rotating the emulsion to remove the solvent to obtain castor oil-based polyurethane; Step S3, preparation of a coating substrate, adding a calculated amount of castor oil polyurethane emulsion, the prepared nano metal oxide modified epoxy resin emulsion, and fluorocarbon resin into a reaction container, adding half of deionized water, and mixing evenly to form a coating substrate; Step S40, preparation of graphene-modified metal organic framework, adding 200g of graphene and 25.2g of sodium bicarbonate to 500mL of DMF solution, stirring for 1h, filtering and drying; adding the filter cake and 100g of metal organic framework to ethanol-water solution, stirring at reflux temperature for 1-3h, and drying after the reaction to obtain the graphene-modified metal organic framework; Step S4, preparation of auxiliary materials, dispersing a silane coupling agent prepared by mixing isobutyltriethoxysilane and a bisaminosilane coupling agent in a mass ratio of 1:0.5, a graphene-modified metal organic framework, and graphene in the remaining deionized water to form an auxiliary material for coating; Step S5, mixing the coating base material and auxiliary materials obtained in steps S3 and S4, adding a sodium silicate-based binder, and mixing evenly to obtain an anti-corrosion coating for steel structures.

[0030] Comparative Example 1 uses acrylic polyurethane topcoat produced by Shandong Lingsai Paint Co., Ltd.; Comparative Example 2 uses steel structure fluorocarbon paint sold by Chaofeng Hardware Building Materials Business Department in Huiji District, Zhengzhou City.

[0031] The performance tests of the anticorrosive coatings prepared in Examples 1-5 are as follows:

[0032] It can be seen from the table that the anti-corrosion coating used in this application for steel structures has good flash rust inhibition compared with commercially available anti-corrosion coatings, and has been greatly improved compared with the adhesion test on the surface just now. The adhesion performance after the salt spray test is still good, the weather resistance performance is good, and the coating can be used stably.

[0033] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of this invention patent through the above description. The technical scope of this invention patent is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. Anti-corrosion coating applied to steel structure, characterized by: The anti-corrosion coating comprises the following components by weight: 20-40 parts of nano metal oxide modified epoxy resin emulsion; 20-40 parts of castor oil-based polyurethane emulsion; 15-30 parts of fluorocarbon resin emulsion; 1-5 parts of silane coupling agent; 2-10 parts of graphene modified metal organic framework; 0.3-1 part of water-based inorganic adhesive; 2-5 parts of filler; 20 parts of deionized water.

2. The anticorrosive coating for steel structure according to claim 1, characterized in that: The metal oxide in the nano-metal oxide modified epoxy resin emulsion is CrO2, TiO2, ZrO2 or SiO2.

3. The anticorrosive coating for steel structure according to claim 1, characterized in that: The silane coupling agent is a silane coupling agent prepared by mixing isobutyltriethoxysilane and bisaminosilane coupling agent in a mass ratio of 1:0.

5.

4. The anticorrosive coating for steel structure according to claim 1, characterized in that: The aqueous inorganic adhesive is one or more of a sodium silicate-based adhesive and a copper oxide phosphate adhesive.

5. The anticorrosive coating for steel structure according to claim 1, characterized in that: The filler is one or more of calcium carbonate, attapulgite and graphene.

6. The method for preparing the anticorrosive coating for steel structure according to any one of claims 1 to 5, characterized in that: The steps include: Step S1, preparation of nano-metal oxide modified epoxy resin emulsion: adding nano-metal oxide and diphenylmethane diisocyanate into a reaction container, reacting at 80°C-90°C for 30min-1h, adding epoxy resin, keeping the temperature for 2h, cooling and degassing, and obtaining nano-metal oxide modified epoxy resin emulsion; Step S2, preparation of castor oil-based polyurethane, drying and dehydrating castor oil at 80° C. for pretreatment, weighing a calculated amount of castor oil and polyethylene glycol monomethyl ether, using acetone as a solvent, adding diisophorone diisocyanate and reacting for 2-5 hours at a reaction temperature of 65-75° C.; after cooling, adding deionized water and stirring to emulsify, rotating the emulsion to remove the solvent to obtain castor oil-based polyurethane; Step S3, preparation of a coating substrate, adding a calculated amount of castor oil polyurethane emulsion, the prepared nano metal oxide modified epoxy resin emulsion, and fluorocarbon resin into a reaction container, adding half of deionized water, and mixing evenly to form a coating substrate; Step S4, preparation of auxiliary materials, dispersing the silane coupling agent, the graphene-modified metal organic framework, and the filler in the remaining deionized water to form auxiliary materials for coatings; Step S5, mixing the coating base material and auxiliary materials obtained in steps S3 and S4, adding a water-based inorganic adhesive, and mixing evenly to obtain an anti-corrosion coating for steel structures.

7. The method for preparing the anticorrosive coating for steel structure according to claim 1, characterized in that: The molar ratio of the nano metal oxide to diphenylmethane diisocyanate is 1:(0.1-0.4).

8. The method for preparing the anticorrosive coating for steel structure according to claim 1, characterized in that: The mass ratio between castor oil groups and polyethylene glycol monomethyl ether in the castor oil-based polyurethane is (0.25-4):

1.

9. The method for preparing the anticorrosive coating for steel structure according to claim 1, characterized in that: The preparation method of the graphene-modified metal organic framework comprises the following steps: adding graphene and sodium bicarbonate into a DMF solution, stirring for 1 hour, filtering and drying; adding the filter cake and the metal organic framework into an ethanol-water solution, stirring for 1-3 hours at a reflux temperature, and drying after the reaction to obtain the graphene-modified metal organic framework.

10. The method for preparing the anticorrosive coating for steel structure according to claim 9, characterized in that: The weight ratio of the graphene to the metal organic framework is (0.6-3):1.

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