Aqueous on-rust anticorrosive paint

Abstract

The invention relates to a water-based on-rust anti-corrosion coating for a rusted steel structure. The water-based on-rust anti-corrosion coating comprises the following components in percentage by weight: 30-50% of water-based epoxy emulsion, 5-10% of water-based silicone acrylic emulsion, 10-20% of basalt, 10-15% of steel slag powder, 1-3% of slag powder, 1-2% of titanium dioxide, 1-4% of tannic acid, 0.5-1% of gallic acid, 0.5-1% of citric acid, 0.5-1% of a flatting agent and the balance of water. The water-based on-rust anti-corrosion coating has the advantages of being good in environmental protection property, low in cost, good in anti-corrosion performance and the like, and is suitable for on-site anti-corrosion maintenance of a rusted steel structure.

Description

Technical Field

[0001] The present invention relates to an aqueous rust-inhibiting and anti-corrosion coating, belonging to the technical field of steel structure anti-corrosion. Background Art

[0002] During the long-term operation of steel structures, they will be corroded by the surrounding environment and rust. Brushing anti-corrosion coatings is the most common method for on-site anti-corrosion maintenance of rusty steel structures. Since rust will hinder the bonding force between the paint film and the steel substrate, mechanical methods such as sandblasting and mechanical grinding are usually used on-site to remove rust. This method is inconvenient to operate and has a high rust removal cost. Chinese Patent CN118256102A discloses an aqueous rust-inhibiting and anti-corrosion coating for steel structures, which uses phosphoric acid as a rust conversion agent and does not meet environmental protection requirements. Chinese Patent CN112760016A discloses an aqueous epoxy zinc-rich coating, which uses phytic acid to chelate metal ions to solve the problem of the rust layer on steel structures. Although environmentally friendly organic acids such as phytic acid, citric acid, oxalic acid, salicylic acid, tannic acid, and gallic acid can complex divalent and trivalent iron ions to achieve a rust removal effect, they will also react with zinc powder to generate hydrogen, which affects the rust removal effect. Summary of the Invention

[0003] In order to solve the problem that zinc powder affects the rust removal effect of organic acids, the present invention provides a zinc-free aqueous rust-inhibiting and anti-corrosion coating, which is composed of the following substances in weight percentages: 30%-50% aqueous epoxy emulsion, 5%-10% aqueous silicone-acrylic emulsion, 10%-20% basalt, 10-15% steel slag powder, 1%-3% slag powder, 1%-2% titanium dioxide, 1-4% tannic acid, 0.5-1% gallic acid, 0.5-1% citric acid, 0.5-1% leveling agent, and the balance is water.

[0004] The solid content of the aqueous epoxy emulsion is 47% - 53%, and the epoxy equivalent is 400 - 800G / EG. The aqueous silicone-acrylic emulsion is an organosilicon-modified acrylic resin emulsion, and the solid content is 40% - 50%. The basalt is in the form of 325-mesh to 800-mesh scales. The steel slag powder is 400-mesh. The slag powder is 400-mesh. The titanium dioxide is rutile type, and the particle size is 45 microns. The leveling agent is a polyurethane associative compound.

[0005] The specific preparation steps of the present invention are as follows: The waterborne rust-inhibiting anti-corrosion coating of the present invention is divided into two groups, A and B. Group A consists of waterborne epoxy emulsion, waterborne silicone-acrylic emulsion, basalt, steel slag powder, slag powder, and titanium dioxide. Group B consists of tannic acid, gallic acid, citric acid, leveling agent, and water. The operating steps for preparing the coating are as follows: Weigh the waterborne epoxy emulsion, waterborne silicone-acrylic emulsion, basalt, steel slag powder, slag powder, and titanium dioxide respectively according to weight percentages. First, put the waterborne epoxy emulsion and waterborne silicone-acrylic emulsion into a ball mill, and gradually add solid powders such as basalt, steel slag powder, slag powder, and titanium dioxide during the ball milling process. After 20 - 30 minutes of ball milling and filtering through a 200-mesh sieve, Component A is prepared. Similarly, weigh tannic acid, gallic acid, citric acid, leveling agent, and water respectively according to weight percentages. First, put the leveling agent and water into a disperser, and gradually add solid powders such as tannic acid, gallic acid, and citric acid during the stirring process. After stirring at 600 - 800 rpm for 30 minutes, Group B is completed. Mix Component A and Group B and stir for 5 - 10 minutes, then the surface of the rusty steel structure can be coated.

[0006] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Using basalt, steel slag powder, and slag powder instead of zinc to form a stable and dense protective layer. Basalt scales can form a maze effect within the epoxy resin, hindering the direct contact of air, moisture, and corrosive substances with the steel structure, playing a physical barrier protection role. Steel slag powder and slag powder have certain pozzolanic activity and can undergo a hydration reaction with water to generate cementitious hydration products, improving the denseness and film-forming property of the coating. Steel slag powder and slag powder belong to solid wastes and are inexpensive. The use of steel slag powder and slag powder in the present invention can greatly reduce the product cost and realize the utilization of solid wastes.

[0007] (2) Tannic acid, gallic acid, and citric acid are commonly used organic rust conversion agents. However, tannic acid has a demulsifying effect, which can destroy the stability of the emulsion system and can also undergo a cross-linking reaction with the waterborne epoxy emulsion, promoting the curing of the waterborne epoxy emulsion. In the present invention, tannic acid, gallic acid, and citric acid are used as Group B, which can avoid the damage of tannic acid to the waterborne epoxy emulsion and improve the storage stability of the product. At the same time, tannic acid and gallic acid belong to polyphenolic compounds, which contain multiple phenolic hydroxyl groups and can form stable complexes with metal ions, helping to dissolve rust. Citric acid is a strong organic acid with good acidic dissolution ability and can react with metal ions in rust to convert them into soluble citrates. The three work together to dissolve rust through acid at a lower total acid concentration and in a shorter time, and more effectively remove rust through complexation, thereby reducing the corrosion risk to the steel structure.

[0008] (3) Waterborne epoxy resins are widely used in anti-corrosion coatings for steel structures due to their excellent adhesion properties. However, epoxy resins have relatively low anti-aging performance. When exposed to harsh environments such as ultraviolet light for a long time, the coating is prone to phenomena such as powdering, cracking, and peeling, which greatly shortens the service life of the anti-corrosion coating for steel structures. The silicon-oxygen bond in the molecular structure of silicone-acrylic resin has a relatively high bond energy, which can effectively resist the erosion of environmental factors such as ultraviolet light and ozone. When the waterborne silicone-acrylic emulsion is blended with the waterborne epoxy emulsion, the silicone-acrylic resin is uniformly dispersed in the coating. On the one hand, it crosslinks with the epoxy resin to form a denser network structure, enhancing the physical properties of the coating; on the other hand, the silicone-acrylic resin migrates to the surface of the coating to form a silicone oxide protective layer with a low surface energy, significantly improving the weather resistance of the coating and effectively delaying the aging process of the coating. Detailed implementation manners

[0009] The following examples are only for explaining the technical solutions recorded in the claims and do not limit the scope of protection of the claims.

[0010] Example 1 A waterborne rust-inhibiting anti-corrosion coating is divided into two groups, A and B. Group A consists of a waterborne epoxy emulsion, a waterborne silicone-acrylic emulsion, basalt, steel slag powder, slag powder, and titanium dioxide. Group B consists of tannic acid, gallic acid, citric acid, a leveling agent, and water. The weight percentages of each component are as follows: 30% waterborne epoxy emulsion, 10% waterborne silicone-acrylic emulsion, 20% basalt, 10% steel slag powder, 1% slag powder, 1% titanium dioxide, 4% tannic acid, 0.5% gallic acid, 0.5% citric acid, 1% leveling agent, and the balance is water. Among them, the solid content of the waterborne epoxy emulsion is 47%, and the epoxy equivalent is 400 G / EG. The solid content of the waterborne silicone-acrylic emulsion is 40%. The basalt is in the form of 325-mesh flakes. The steel slag powder is 400 mesh. The slag powder is 400 mesh. The titanium dioxide is rutile type with a particle size of 45 microns. The leveling agent is a polyurethane associative compound.

[0011] Example 2 A waterborne rust-inhibiting anti-corrosion coating is divided into two groups, A and B. Group A consists of a waterborne epoxy emulsion, a waterborne silicone-acrylic emulsion, basalt, steel slag powder, slag powder, and titanium dioxide. Group B consists of tannic acid, gallic acid, citric acid, a leveling agent, and water. The weight percentages of each component are as follows: 50% waterborne epoxy emulsion, 5% waterborne silicone-acrylic emulsion, 10% basalt, 15% steel slag powder, 3% slag powder, 2% titanium dioxide, 1% tannic acid, 1% gallic acid, 1% citric acid, 0.5% leveling agent, and the balance is water. Among them, the solid content of the waterborne epoxy emulsion is 53%, and the epoxy equivalent is 800 G / EG. The solid content of the waterborne silicone-acrylic emulsion is 50%. The basalt is in the form of 800-mesh flakes. The steel slag powder is 400 mesh. The slag powder is 400 mesh. The titanium dioxide is rutile type with a particle size of 45 microns. The leveling agent is a polyurethane associative compound.

[0012] Example 3 A waterborne rust-inhibiting anticorrosive coating is divided into two groups, A and B. Group A consists of a waterborne epoxy emulsion, a waterborne silicone-acrylic emulsion, basalt, steel slag powder, slag powder, and titanium dioxide. Group B consists of tannic acid, gallic acid, citric acid, a leveling agent, and water. The weight percentages of each component are as follows: 40% waterborne epoxy emulsion, 8% waterborne silicone-acrylic emulsion, 15% basalt, 12% steel slag powder, 2% slag powder, 1.5% titanium dioxide, 3% tannic acid, 0.8% gallic acid, 0.8% citric acid, 0.8% leveling agent, and the balance is water. Among them, the solid content of the waterborne epoxy emulsion is 50%, and the epoxy equivalent is 600 G / EG. The solid content of the waterborne silicone-acrylic emulsion is 45%. The basalt is in the form of 400-mesh flakes. The steel slag powder is 400 mesh. The slag powder is 400 mesh. The titanium dioxide is rutile type with a particle size of 45 microns. The leveling agent is a polyurethane associative compound.

[0013] Example 4 A waterborne rust-inhibiting anticorrosive coating is divided into two groups, A and B. Group A consists of a waterborne epoxy emulsion, a waterborne silicone-acrylic emulsion, basalt, steel slag powder, slag powder, and titanium dioxide. Group B consists of tannic acid, gallic acid, citric acid, a leveling agent, and water. The weight percentages of each component are as follows: 45% waterborne epoxy emulsion, 6% waterborne silicone-acrylic emulsion, 18% basalt, 11% steel slag powder, 2% slag powder, 1.5% titanium dioxide, 2% tannic acid, 0.9% gallic acid, 0.6% citric acid, 0.9% leveling agent, and the balance is water. Among them, the solid content of the waterborne epoxy emulsion is 52%, and the epoxy equivalent is 500 G / EG. The solid content of the waterborne silicone-acrylic emulsion is 45%. The basalt is in the form of 600-mesh flakes. The steel slag powder is 400 mesh. The slag powder is 400 mesh. The titanium dioxide is rutile type with a particle size of 45 microns. The leveling agent is a polyurethane associative compound.

[0014] The preparation method of the waterborne rust-inhibiting anticorrosive coatings in Examples 1-4 is as follows: Weigh the waterborne epoxy emulsion, waterborne silicone-acrylic emulsion, basalt, steel slag powder, slag powder, and titanium dioxide respectively according to the weight percentages. First, put the waterborne epoxy emulsion and the waterborne silicone-acrylic emulsion into a ball mill, and gradually add solid powders such as basalt, steel slag powder, slag powder, and titanium dioxide during the ball milling process. After 20-30 minutes of ball milling and filtering through a 200-mesh sieve, Component A is prepared. Similarly, weigh tannic acid, gallic acid, citric acid, a leveling agent, and water respectively according to the weight percentages. First, put the leveling agent and water into a disperser, and gradually add solid powders such as tannic acid, gallic acid, and citric acid during the stirring process. After stirring at 600-800 rpm for 30 minutes, Component B is completed. After mixing and stirring Component A and Component B for 5-10 minutes, the surface of the rusty steel structure can be coated.

[0015] Comparative Example 1 A waterborne rust-inhibiting anticorrosive coating, comprising 38% waterborne epoxy emulsion, 19% waterborne polyamide curing agent, 20% zinc, 2% titanium dioxide, 4% tannic acid, 8% aluminum tripolyphosphate, 1% leveling agent, 1% dispersant, 5% thickener, and the balance being water.

[0016] Take a number of the same rusted steel substrates, remove the loose rust on the rusted steel substrates, apply Examples 1-4 and Comparative Example 1 to the surfaces of the rusted steel substrates, and after curing at room temperature for 4 weeks, test the resistance to artificial weathering and neutral salt spray according to HG / T 5176-2017 "Waterborne Anticorrosive Coatings for Steel Structures". The results are shown in Table 1. It can be seen that the aging resistance and neutral salt spray corrosion resistance of the rusted steel substrates (Examples 1-4) of the present invention are higher than those of the waterborne epoxy zinc-rich rust-inhibiting anticorrosive coating (Comparative Example 1). This shows that the waterborne zinc-free rust-inhibiting anticorrosive coating of the present invention has the function of being able to be coated with rust and is more suitable for rusted steel substrates.

[0017] Table 1 Performance Table of Waterborne Rust-inhibiting Anticorrosive Coatings Aging time Neutral salt spray time Comparative example 1 500h 500h Example 1 1000h 720h Example 2 1000h 720h Example 3 1000h 720h Example 4 1000h 720h The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An aqueous rust-inhibiting anti-corrosion paint, characterized in that, Comprising the following components by weight percentage: 30% - 50% waterborne epoxy emulsion, 5% - 10% waterborne silicone-acrylic emulsion, 10% - 20% basalt, 10 - 15% steel slag powder, 1% - 3% slag powder, 1% - 2% titanium dioxide, 1 - 4% tannic acid, 0.5 - 1% gallic acid, 0.5 - 1% citric acid, 0.5 - 1% leveling agent, and the balance is water.

2. The waterborne rust-inhibiting anticorrosive paint according to claim 1, wherein Group A consists of waterborne epoxy emulsion, waterborne silicone-acrylic emulsion, basalt, steel slag powder, slag powder, and titanium dioxide. Group B consists of tannic acid, gallic acid, citric acid, leveling agent, and water.

3. The waterborne rust-inhibiting anti-corrosion coating according to claim 1 or 2, characterized in that, The solid content of the waterborne epoxy emulsion is 47% - 53%, and the epoxy equivalent is 400 - 800 G / EG. The waterborne silicone-acrylic emulsion is an organosilicon-modified acrylic resin emulsion with a solid content of 40% - 50%.

4. The waterborne rust-inhibiting anti-corrosion coating according to claim 1 or 2, characterized in that The basalt is in the form of 325 - mesh to 800 - mesh scales. The steel slag powder is 400 - mesh. The slag powder is 400 - mesh. The titanium dioxide is rutile type with a particle size of 45 microns. The leveling agent is a polyurethane associative compound.