Production and preparation process of heavy-duty waterborne epoxy primer suitable for high-salt and high-humidity environment

Abstract

The application discloses a production and preparation process of a heavy-duty water-based epoxy primer suitable for a high-salt and high-humidity environment, and relates to the technical field of water-based epoxy primer production. The raw materials are as follows: 30-50 parts of bisphenol A type water-based epoxy resin emulsion, 10-20 parts of a curing agent T-31, 3.5-5 parts of a reinforced anti-settling agent, 8-12 parts of zinc phosphate, 5-8 parts of aluminum tripolyphosphate, 10-15 parts of precipitated barium sulfate, 3-6 parts of silicon powder, 0.8-1.2 parts of a polyacrylic acid sodium salt dispersing agent, 0.4-0.8 parts of an organic silicon defoaming agent, 0.3-0.7 parts of an acrylic ester leveling agent and 0.6-1 part of a polyurethane thickening agent. The bentonite in the reinforced anti-settling agent and the modified phosphosilicate zirconium powder can improve the microstructure of the primer system, the coating is more compact, the primer can be conveniently applied to a high-salt and high-humidity environment, and the salt mist resistance of the water-based epoxy primer is enhanced.

Description

Technical Field

[0001] This invention relates to the field of waterborne epoxy primer production technology, and more specifically, to a production process for a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments. Background Technology

[0002] Waterborne epoxy primers, as an environmentally friendly coating, use water as a solvent or dispersion medium. They have advantages such as low VOC content, low odor, and non-flammability, and are gradually becoming a substitute for traditional solvent-based anti-corrosion coatings. They can provide good anti-corrosion performance under normal conditions and are widely used in construction, industrial equipment and other fields.

[0003] However, the existing waterborne epoxy primers still have insufficient anti-corrosion performance in high-salt and high-humidity environments. In high-salt environments, a large amount of salt is easily adsorbed on the coating surface and penetrates into the substrate through the pores of the coating, causing electrochemical corrosion. High-humidity environments will keep the coating in a damp state for a long time, reducing the adhesion of the coating and accelerating the aging and damage of the coating. Under such dual effects, the anti-corrosion life of ordinary waterborne epoxy primers is greatly shortened. It may blister, peel off, rust and other phenomena may occur within just a few months to a few years, which cannot meet the long-term heavy anti-corrosion requirements in high-salt and high-humidity environments.

[0004] No effective solutions have yet been proposed to address the problems in the relevant technologies. Summary of the Invention

[0005] To address the problems in related technologies, this invention proposes a production process for a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments, thereby overcoming the aforementioned technical problems in existing related technologies.

[0006] Therefore, the specific technical solution adopted by the present invention is as follows:

[0007] A heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments comprises the following raw materials in parts by weight: 30-50 parts of bisphenol A type waterborne epoxy resin emulsion, 10-20 parts of curing agent T-31, 3.5-5 parts of reinforcing anti-settling agent, 8-12 parts of zinc phosphate, 5-8 parts of aluminum tripolyphosphate, 10-15 parts of precipitated barium sulfate, 3-6 parts of silica powder, 0.8-1.2 parts of sodium polyacrylate dispersant, 0.4-0.8 parts of silicone defoamer, 0.3-0.7 parts of acrylate leveling agent, and 0.6-1 part of polyurethane thickener;

[0008] The enhanced anti-settling agent is prepared by the following steps:

[0009] Step 1: Heat deionized water to 70°C and add it to the reactor. Start stirring and slowly add bentonite. Keep the temperature and continue stirring for 30 minutes until a uniform gel is formed to obtain the bentonite gel system.

[0010] Step 2: In a separate container, mix KH-560 and ethanol at a mass ratio of 1:1 and hydrolyze for 10 minutes. Then add zirconium phosphosilicate powder and disperse at a high speed of 2000 rpm for 15 minutes to obtain modified powder. Add the modified powder to the bentonite gel system and switch to a high-speed homogenizer for further processing. During the processing, circulate the mixture through a colloid mill twice with a gap of 50 μm. Add deionized water and ammonia to adjust the pH to 9.0-10.0, so that the viscosity is 7500-8000 mPa·s, to obtain the enhanced anti-settling agent.

[0011] In a preferred embodiment, the mass ratio of bentonite to deionized water used in step 1 is 1:3, the stirring speed in step 1 is 600 r / min, the bentonite in step 1 is in solid granular form, the bentonite particle size is ≤80 mesh, and the effective content of bentonite is ≥60%.

[0012] In a preferred embodiment, the high-speed homogenizer used in step 2 has a rotation speed of 3000 r / min and a processing time of 20 minutes. The mass ratio of KH-560 to zirconium phosphosilicate powder in step 2 is 1:6.

[0013] A manufacturing process for a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments includes the following preparation steps:

[0014] S1. Weigh the following raw materials according to the following mass percentages: the raw materials consist of 30-50 parts of bisphenol A type waterborne epoxy resin emulsion, 10-20 parts of curing agent T-31, 3.5-5 parts of reinforcing anti-settling agent, 8-12 parts of zinc phosphate, 5-8 parts of aluminum tripolyphosphate, 10-15 parts of precipitated barium sulfate, 3-6 parts of silica powder, 0.8-1.2 parts of sodium polyacrylate dispersant, 0.4-0.8 parts of silicone defoamer, 0.3-0.7 parts of acrylate leveling agent, and 0.6-1 parts of polyurethane thickener;

[0015] S2. Add an appropriate amount of deionized water to the mixing tank, then add sodium polyacrylate dispersant and stir for 5-10 minutes to fully dissolve the dispersant in the deionized water. Then add zinc phosphate, aluminum tripolyphosphate, precipitated barium sulfate and silica powder while stirring. The feeding time should be controlled at 10-15 minutes. After the feeding is completed, increase the stirring speed and continue stirring for 20-30 minutes to make the pigments and fillers initially dispersed evenly, and obtain pre-dispersed material A.

[0016] S3. Transfer the pre-dispersed material A to a sand mill, turn on the sand mill to grind, and circulate the grinding until the fineness of the pre-dispersed material A is ≤30μm to obtain the grinding material;

[0017] S4. Return the grinding slurry to the dispersion tank, adjust the rotation speed to 400 r / min, and slowly add the anti-settling agent. Continue stirring for 15 minutes until the system shows a uniform blue-gray fluorescence.

[0018] S5. Reduce the stirring speed and slowly add the bisphenol A type waterborne epoxy resin emulsion. After the addition is complete, continue stirring for 30-40 minutes. Then add the silicone defoamer and acrylate leveling agent in sequence. Stir for 5-10 minutes after each additive is added. Then dilute the polyurethane thickener with 3 times the amount of deionized water and slowly add it dropwise to adjust the viscosity to 85-90KU to obtain the semi-finished primer.

[0019] S6. Mix the curing agent T-31 and deionized water in a container at a 1:1 ratio until homogeneous. Continue stirring and mixing. Slowly add the mixed curing agent solution to the semi-finished primer while stirring. The stirring speed is 100 r / min, and the addition time is controlled at 10-15 minutes. After the addition is complete, continue stirring to ensure that the curing agent and the semi-finished primer are fully mixed. Transfer the mixture to a vacuum degassing kettle for degassing and then filter it through a 200-mesh filter to obtain the finished primer.

[0020] In a preferred embodiment, the mass ratio of deionized water to sodium polyacrylate dispersant in S2 is 30:1, the stirring speed after adding sodium polyacrylate dispersant is 100 r / min, and the stirring speed after adding material is 300 r / min.

[0021] In a preferred embodiment, the grinding feed flow rate in S3 is 18 L / min, and the grinding pressure is 1 MPa.

[0022] In a preferred embodiment, the stirring speed in step S5 is reduced to 200 r / min, and the feeding time for adding the bisphenol A type waterborne epoxy resin emulsion is 15 minutes.

[0023] In a preferred embodiment, the stirring speed of the curing agent T-31 and deionized water in S6 is 300 r / min, and the stirring time is 10 minutes. When the curing agent solution is added to the semi-finished primer, the stirring speed is 100 r / min. After the addition is completed, stirring continues for 20 minutes to ensure that the curing agent and the semi-finished primer are fully and evenly mixed. The parameters of the vacuum degassing kettle are -0.08 MPa and the degassing time is 15 minutes.

[0024] In a preferred embodiment, the bisphenol A type waterborne epoxy resin emulsion used is E-44, the silica powder is 300 mesh, the silicone defoamer is BYK-028, the acrylate leveling agent is OP-8035, and the polyurethane thickener is PU-40.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. This invention adds a reinforcing anti-settling agent to the raw materials of waterborne epoxy primer. The bentonite and modified zirconium phosphosilicate powder in the reinforcing anti-settling agent can improve the microstructure of the primer in the primer system, making the coating more dense. When the primer is applied to a high-salt and high-humidity environment, this dense structure can effectively reduce the penetration channels of corrosive media such as chloride ions in salt spray, enhance the salt spray resistance of waterborne epoxy primer, and improve its actual performance in harsh environments.

[0027] 2. The anti-settling agent of the present invention can work synergistically with other components in the primer to change the wettability and adhesion properties of the primer. By strengthening the active groups contained in the anti-settling agent, when the primer is applied to the substrate, it can enhance the physical adsorption and chemical bonding between the primer and the substrate. The nanosheet structure of bentonite gel is oriented on the substrate surface, increasing the mechanical anchoring effect, so that the primer can better adhere to the substrate surface and improve the adhesion of the coating.

[0028] 3. This invention reduces the water absorption rate of the coating by utilizing the hydrophobic crystal structure of zirconium phosphosilicate, forming an effective waterproof barrier on the primer surface. When the primer comes into contact with water, the bentonite gel network blocks the capillary pores, preventing water molecules from penetrating and reducing water absorption, thereby improving the water resistance of the water-based epoxy primer, extending its water resistance time, and enhancing its functionality. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a flowchart of a production process for a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments, according to an embodiment of the present invention. Detailed Implementation

[0031] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0032] According to an embodiment of the present invention, a production process for a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments is provided.

[0033] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments:

[0034] Example 1:

[0035] According to an embodiment of the present invention, a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments comprises the following raw materials in parts by weight: including;

[0036] A manufacturing process for a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments includes the following preparation steps:

[0037] S1. Weigh the following raw materials according to the following mass percentages: the raw materials consist of 30-50 parts of bisphenol A type waterborne epoxy resin emulsion, 10-20 parts of curing agent T-31, 3.5-5 parts of reinforcing anti-settling agent, 8-12 parts of zinc phosphate, 5-8 parts of aluminum tripolyphosphate, 10-15 parts of precipitated barium sulfate, 3-6 parts of silica powder, 0.8-1.2 parts of sodium polyacrylate dispersant, 0.4-0.8 parts of silicone defoamer, 0.3-0.7 parts of acrylate leveling agent, and 0.6-1 parts of polyurethane thickener;

[0038] S2. Add an appropriate amount of deionized water to the mixing tank, then add sodium polyacrylate dispersant and stir for 5-10 minutes to fully dissolve the dispersant in the deionized water. Then add zinc phosphate, aluminum tripolyphosphate, precipitated barium sulfate and silica powder while stirring. The feeding time should be controlled at 10-15 minutes. After the feeding is completed, increase the stirring speed and continue stirring for 20-30 minutes to make the pigments and fillers initially dispersed evenly, and obtain pre-dispersed material A.

[0039] S3. Transfer the pre-dispersed material A to a sand mill, turn on the sand mill to grind, and circulate the grinding until the fineness of the pre-dispersed material A is ≤30μm to obtain the grinding material;

[0040] S4. Return the grinding slurry to the dispersion tank, adjust the rotation speed to 400 r / min, and slowly add the anti-settling agent. Continue stirring for 15 minutes until the system shows a uniform blue-gray fluorescence.

[0041] S5. Reduce the stirring speed and slowly add the bisphenol A type waterborne epoxy resin emulsion. After the addition is complete, continue stirring for 30-40 minutes. Then add the silicone defoamer and acrylate leveling agent in sequence. Stir for 5-10 minutes after each additive is added. Then dilute the polyurethane thickener with 3 times the amount of deionized water and slowly add it dropwise to adjust the viscosity to 85-90KU to obtain the semi-finished primer.

[0042] S6. Mix the curing agent T-31 and deionized water in a container at a ratio of 1:1 until homogeneous. Continue stirring and mixing. Slowly add the mixed curing agent solution to the semi-finished primer while stirring. The stirring speed is 100 r / min, and the addition time is controlled at 10-15 minutes. After the addition is complete, continue stirring to ensure that the curing agent and the semi-finished primer are fully mixed. Transfer the mixture to a vacuum degassing kettle for degassing and then filter it through a 200-mesh filter to obtain the finished primer.

[0043] In S2, the mass ratio of deionized water to sodium polyacrylate dispersant is 30:1. The stirring speed after adding the sodium polyacrylate dispersant is 100 r / min, and the stirring speed after the addition is 300 r / min. In S3, the grinding feed flow rate is 18 L / min, and the grinding pressure is 1 MPa. In S5, the stirring speed is reduced to 200 r / min, and the addition time of the bisphenol A type waterborne epoxy resin emulsion is 15 minutes. In S6, the stirring speed of the curing agent T-31 and deionized water is 300 r / min, and the stirring time is 10 minutes. When the curing agent solution is added to the semi-finished primer, the stirring speed is 100 r / min. After the addition is completed, stirring continues for 20 minutes to ensure that the curing agent and the semi-finished primer are fully mixed and uniform. The parameters of the vacuum degassing kettle are -0.08 MPa, and the degassing time is 15 minutes.

[0044] The bisphenol A type waterborne epoxy resin emulsion used is E-44, the silica powder is 300 mesh, the organosilicon defoamer is BYK-028, the acrylate leveling agent is OP-8035, and the polyurethane thickener is PU-40.

[0045] The enhanced anti-settling agent is prepared through the following steps:

[0046] Step 1: Heat deionized water to 70°C and add it to the reactor. Start stirring and slowly add bentonite. Keep the temperature and continue stirring for 30 minutes until a uniform gel is formed to obtain the bentonite gel system.

[0047] Step 2: In a separate container, mix KH-560 and ethanol at a mass ratio of 1:1 and hydrolyze for 10 minutes. Then add zirconium phosphosilicate powder and disperse at a high speed of 2000 rpm for 15 minutes to obtain modified powder. Add the modified powder to the bentonite gel system and switch to a high-speed homogenizer for further processing. During the processing, circulate the mixture through a colloid mill twice with a gap of 50 μm. Add deionized water and ammonia to adjust the pH to 9.0-10.0, so that the viscosity is 7500-8000 mPa·s, to obtain the enhanced anti-settling agent.

[0048] The mass ratio of bentonite to deionized water used in step 1 is 1:3. The stirring speed in step 1 is 600 r / min. The bentonite in step 1 is in solid granular form, with a particle size ≤80 mesh and an effective bentonite content ≥60%.

[0049] The high-speed homogenizer used in step 2 has a rotation speed of 3000 r / min and a processing time of 20 minutes. The mass ratio of KH-560 to zirconium phosphosilicate powder in step 2 is 1:6.

[0050] Example 2:

[0051] A heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments, the specific process and preparation flow are as follows:

[0052] Step 1: Weigh the following raw materials according to the mass percentages: The raw materials consist of 30 parts of bisphenol A type waterborne epoxy resin emulsion, 10 parts of curing agent T-31, 3.5 parts of reinforcing anti-settling agent, 8 parts of zinc phosphate, 5 parts of aluminum tripolyphosphate, 10 parts of precipitated barium sulfate, 3 parts of silica powder, 0.8 parts of sodium polyacrylate dispersant, 0.4 parts of silicone defoamer, 0.3 parts of acrylate leveling agent, and 0.6 parts of polyurethane thickener.

[0053] Step 2: Add an appropriate amount of deionized water to the mixing tank, then add 0.8 parts of sodium polyacrylate dispersant, where the mass ratio of deionized water to sodium polyacrylate dispersant is 30:1. Set the stirring speed to 100 r / min and stir for 8 minutes to allow the dispersant to fully dissolve in the deionized water. Then add 8 parts of zinc phosphate, 5 parts of aluminum tripolyphosphate, 10 parts of precipitated barium sulfate, and 3 parts of silica powder while stirring. Control the feeding time to 15 minutes. After the feeding is completed, increase the stirring speed to 300 r / min and continue stirring for 25 minutes to allow the pigments and fillers to be initially and evenly dispersed, obtaining pre-dispersed material A.

[0054] The third step is to transfer the pre-dispersed material A to a sand mill, turn on the sand mill to grind, control the feed flow rate to 18L / min and the grinding pressure to 1MPa, and circulate the grinding until the fineness of the pre-dispersed material A is ≤30μm to obtain the ground material.

[0055] Step 4: Return the grinding slurry to the dispersion tank, adjust the rotation speed to 400 r / min, slowly add 3.5 parts of anti-settling agent, and continue stirring for 15 minutes until the system shows a uniform blue-gray fluorescence;

[0056] Step 5: Reduce the stirring speed to 200 r / min, slowly add 30 parts of bisphenol A type waterborne epoxy resin emulsion, and add the material over 15 minutes. After the material is added, continue stirring for 35 minutes. Then add 0.4 parts of silicone defoamer and 0.3 parts of acrylic leveling agent in sequence. Stir for 10 minutes after each addition. Then dilute 0.6 parts of polyurethane thickener with 3 times the amount of deionized water and slowly add it dropwise to adjust the viscosity to 85-90 KU to obtain a semi-finished primer.

[0057] Step 6: Mix 10 parts of T-31 hardener and deionized water in a 1:1 ratio in a container and stir at 300 rpm for 10 minutes. Slowly add the mixed hardener solution to the semi-finished primer while stirring at 100 rpm. Control the addition time to 15 minutes. After the addition is complete, continue stirring for 20 minutes to ensure that the hardener and semi-finished primer are fully mixed. Transfer the mixture to a vacuum degassing kettle and degas at -0.08 MPa for 15 minutes. Then filter through a 200-mesh filter to obtain the finished primer.

[0058] The enhanced anti-settling agent is prepared through the following steps:

[0059] Step 1: Heat deionized water to 70°C and add it into the reactor. Start stirring at 600 r / min and slowly add bentonite, wherein the mass ratio of bentonite to deionized water is 1:3. Keep the temperature and continue stirring for 30 minutes until a uniform gel is formed to obtain the bentonite gel system.

[0060] Step 2: In a separate container, KH-560 and ethanol are mixed at a mass ratio of 1:1 and hydrolyzed for 10 minutes. Then, zirconium phosphosilicate powder is added and dispersed at a high speed of 2000 rpm for 15 minutes. The mass ratio of KH-560 to zirconium phosphosilicate powder is 1:6. The modified powder is then added to the bentonite gel system and switched to a high-speed homogenizer at 3000 rpm for 20 minutes. During the process, the mixture is circulated twice through a colloid mill with a gap of 50 μm. Deionized water is added and ammonia is added to adjust the pH to 9.0-10.0, so that the viscosity is 7500-8000 mPa·s, thus obtaining the enhanced anti-settling agent.

[0061] The bisphenol A type waterborne epoxy resin emulsion used is E-44, the silica powder is 300 mesh, the organosilicon defoamer is BYK-028, the acrylate leveling agent is OP-8035, and the polyurethane thickener is PU-40. The bentonite used is in solid granular form, with a bentonite particle size ≤80 mesh and an effective bentonite content ≥60%.

[0062] Example 3:

[0063] A heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments, the specific process and preparation flow are as follows:

[0064] Step 1: Weigh the following raw materials according to the mass percentages: The raw materials consist of 50 parts of bisphenol A type waterborne epoxy resin emulsion, 20 parts of curing agent T-31, 5 parts of reinforcing anti-settling agent, 12 parts of zinc phosphate, 8 parts of aluminum tripolyphosphate, 15 parts of precipitated barium sulfate, 6 parts of silica powder, 1.2 parts of sodium polyacrylate dispersant, 0.8 parts of silicone defoamer, 0.7 parts of acrylate leveling agent, and 1 part of polyurethane thickener.

[0065] Step 2: Add an appropriate amount of deionized water to the mixing tank, then add 1.2 parts of sodium polyacrylate dispersant, where the mass ratio of deionized water to sodium polyacrylate dispersant is 30:1. Set the stirring speed to 100 r / min and stir for 8 minutes to allow the dispersant to fully dissolve in the deionized water. Then add 12 parts of zinc phosphate, 8 parts of aluminum tripolyphosphate, 15 parts of precipitated barium sulfate, and 6 parts of silica powder while stirring. Control the feeding time to 15 minutes. After the feeding is completed, increase the stirring speed to 300 r / min and continue stirring for 25 minutes to allow the pigments and fillers to be initially and evenly dispersed, obtaining pre-dispersed material A.

[0066] The third step is to transfer the pre-dispersed material A to a sand mill, turn on the sand mill to grind, control the feed flow rate to 18L / min and the grinding pressure to 1MPa, and circulate the grinding until the fineness of the pre-dispersed material A is ≤30μm to obtain the ground material.

[0067] Step 4: Return the grinding slurry to the dispersion tank, adjust the rotation speed to 400 r / min, slowly add 5 parts of anti-settling agent, and continue stirring for 15 minutes until the system shows a uniform blue-gray fluorescence;

[0068] Step 5: Reduce the stirring speed to 200 r / min, slowly add 50 parts of bisphenol A type waterborne epoxy resin emulsion, and add the material over 15 minutes. After the material is added, continue stirring for 35 minutes. Then add 0.8 parts of silicone defoamer and 0.7 parts of acrylic leveling agent in sequence. Stir for 10 minutes after each addition. Then dilute 1 part of polyurethane thickener with 3 times the amount of deionized water and slowly add it dropwise to adjust the viscosity to 85-90 KU to obtain a semi-finished primer.

[0069] Step 6: Mix 20 parts of T-31 hardener with deionized water in a 1:1 ratio in a container and stir at 300 rpm for 10 minutes. Slowly add the mixed hardener solution to the semi-finished primer while stirring at 100 rpm. Control the addition time to 15 minutes. After the addition is complete, continue stirring for 20 minutes to ensure that the hardener and semi-finished primer are fully mixed. Transfer the mixture to a vacuum degassing kettle and degas at -0.08 MPa for 15 minutes. Then filter through a 200-mesh filter to obtain the finished primer.

[0070] The enhanced anti-settling agent is prepared through the following steps:

[0071] Step 1: Heat deionized water to 70°C and add it into the reactor. Start stirring at 600 r / min and slowly add bentonite, wherein the mass ratio of bentonite to deionized water is 1:3. Keep the temperature and continue stirring for 30 minutes until a uniform gel is formed to obtain the bentonite gel system.

[0072] Step 2: In a separate container, KH-560 and ethanol are mixed at a mass ratio of 1:1 and hydrolyzed for 10 minutes. Then, zirconium phosphosilicate powder is added and dispersed at a high speed of 2000 rpm for 15 minutes. The mass ratio of KH-560 to zirconium phosphosilicate powder is 1:6. The modified powder is then added to the bentonite gel system and switched to a high-speed homogenizer at 3000 rpm for 20 minutes. During the process, the mixture is circulated twice through a colloid mill with a gap of 50 μm. Deionized water is added and ammonia is added to adjust the pH to 9.0-10.0, so that the viscosity is 7500-8000 mPa·s, thus obtaining the enhanced anti-settling agent.

[0073] The bisphenol A type waterborne epoxy resin emulsion used is E-44, the silica powder is 300 mesh, the organosilicon defoamer is BYK-028, the acrylate leveling agent is OP-8035, and the polyurethane thickener is PU-40. The bentonite used is in solid granular form, with a bentonite particle size ≤80 mesh and an effective bentonite content ≥60%.

[0074] Comparative Example 1:

[0075] A water-based epoxy primer, the specific process and preparation flow are as follows:

[0076] Step 1: Weigh the following raw materials according to the following mass proportions: The raw materials consist of 30 parts of bisphenol A type waterborne epoxy resin emulsion, 10 parts of curing agent T-31, 8 parts of zinc phosphate, 5 parts of aluminum tripolyphosphate, 10 parts of precipitated barium sulfate, 3 parts of silica powder, 0.8 parts of sodium polyacrylate dispersant, 0.4 parts of silicone defoamer, 0.3 parts of acrylate leveling agent, and 0.6 parts of polyurethane thickener.

[0077] Step 2: Add an appropriate amount of deionized water to the mixing tank, then add 0.8 parts of sodium polyacrylate dispersant, where the mass ratio of deionized water to sodium polyacrylate dispersant is 30:1. Set the stirring speed to 100 r / min and stir for 8 minutes to allow the dispersant to fully dissolve in the deionized water. Then add 8 parts of zinc phosphate, 5 parts of aluminum tripolyphosphate, 10 parts of precipitated barium sulfate, and 3 parts of silica powder while stirring. Control the feeding time to 15 minutes. After the feeding is completed, increase the stirring speed to 300 r / min and continue stirring for 25 minutes to allow the pigments and fillers to be initially and evenly dispersed, obtaining pre-dispersed material A.

[0078] The third step is to transfer the pre-dispersed material A to a sand mill, turn on the sand mill to grind, control the feed flow rate to 18L / min and the grinding pressure to 1MPa, and circulate the grinding until the fineness of the pre-dispersed material A is ≤30μm to obtain the ground material.

[0079] Step 4: Return the grinding slurry to the dispersion tank, adjust the stirring speed to 200 r / min, and slowly add 30 parts of bisphenol A type waterborne epoxy resin emulsion over 15 minutes. After the addition is complete, continue stirring for 35 minutes. Then, add 0.4 parts of silicone defoamer and 0.3 parts of acrylic leveling agent in sequence. Stir for 10 minutes after each addition. Then, dilute 0.6 parts of polyurethane thickener with 3 times the amount of deionized water and slowly add it dropwise to adjust the viscosity to 85-90 KU to obtain a semi-finished primer.

[0080] Step 5: Mix 10 parts of T-31 hardener and deionized water in a 1:1 ratio in a container and stir at 300 rpm for 10 minutes. Slowly add the mixed hardener solution to the semi-finished primer while stirring at 100 rpm. Control the addition time to 15 minutes. After the addition is complete, continue stirring for 20 minutes to ensure that the hardener and semi-finished primer are fully mixed. Transfer the mixture to a vacuum degassing kettle and degas at -0.08 MPa for 15 minutes. Then filter through a 200-mesh filter to obtain the finished primer.

[0081] The bisphenol A type waterborne epoxy resin emulsion used is E-44, the silica powder is 300 mesh, the silicone defoamer is BYK-028, the acrylate leveling agent is OP-8035, and the polyurethane thickener is PU-40.

[0082] Comparative Example 2:

[0083] A water-based epoxy primer, the specific process and preparation flow are as follows:

[0084] Step 1: Weigh the following raw materials according to the mass percentages: The raw materials consist of 50 parts of bisphenol A type waterborne epoxy resin emulsion, 20 parts of curing agent T-31, 12 parts of zinc phosphate, 8 parts of aluminum tripolyphosphate, 15 parts of precipitated barium sulfate, 6 parts of silica powder, 1.2 parts of sodium polyacrylate dispersant, 0.8 parts of silicone defoamer, 0.7 parts of acrylate leveling agent, and 1 part of polyurethane thickener.

[0085] Step 2: Add an appropriate amount of deionized water to the mixing tank, then add 1.2 parts of sodium polyacrylate dispersant, where the mass ratio of deionized water to sodium polyacrylate dispersant is 30:1. Set the stirring speed to 100 r / min and stir for 8 minutes to allow the dispersant to fully dissolve in the deionized water. Then add 12 parts of zinc phosphate, 8 parts of aluminum tripolyphosphate, 15 parts of precipitated barium sulfate, and 6 parts of silica powder while stirring. Control the feeding time to 15 minutes. After the feeding is completed, increase the stirring speed to 300 r / min and continue stirring for 25 minutes to allow the pigments and fillers to be initially and evenly dispersed, obtaining pre-dispersed material A.

[0086] The third step is to transfer the pre-dispersed material A to a sand mill, turn on the sand mill to grind, control the feed flow rate to 18L / min and the grinding pressure to 1MPa, and circulate the grinding until the fineness of the pre-dispersed material A is ≤30μm to obtain the ground material.

[0087] Step 4: Return the grinding slurry to the dispersion tank, adjust the stirring speed to 200 r / min, and slowly add 50 parts of bisphenol A type waterborne epoxy resin emulsion over 15 minutes. After the addition is complete, continue stirring for 35 minutes. Then, add 0.8 parts of silicone defoamer and 0.7 parts of acrylate leveling agent in sequence. Stir for 10 minutes after each addition. Then, dilute 1 part of polyurethane thickener with 3 times the amount of deionized water and slowly add it dropwise to adjust the viscosity to 85-90 KU to obtain a semi-finished primer.

[0088] Step 5: Mix 20 parts of T-31 hardener and deionized water in a 1:1 ratio in a container and stir at 300 rpm for 10 minutes. Slowly add the mixed hardener solution to the semi-finished primer while stirring at 100 rpm. Control the addition time to 15 minutes. After the addition is complete, continue stirring for 20 minutes to ensure that the hardener and semi-finished primer are fully mixed. Transfer the mixture to a vacuum degassing kettle and degas at -0.08 MPa for 15 minutes. Then filter through a 200-mesh filter to obtain the finished primer.

[0089] The bisphenol A type waterborne epoxy resin emulsion used is E-44, the silica powder is 300 mesh, the silicone defoamer is BYK-028, the acrylate leveling agent is OP-8035, and the polyurethane thickener is PU-40.

[0090] Experimental Example 1:

[0091] The waterborne epoxy primers obtained in Examples 2 and 3 and Comparative Examples 1 and 2 were subjected to performance tests, including salt spray resistance, adhesion, water resistance, and settling stability tests. The test results are shown in Tables 1, 2, 3, and 4.

[0092] Table 1: Salt Spray Resistance Test Table for Waterborne Epoxy Primers

[0093]

[0094] The specific steps for the salt spray resistance test are as follows: A sandblasted Q235 steel plate with dimensions of 150×70×1mm is coated with the primers of Examples 2 and 3 and Comparative Examples 1 and 2, respectively, with a dry film thickness of 50±5μm. After curing at room temperature for 7 days, a forked scratch is made with a knife, with the scratches reaching the substrate. The plate is then placed in a salt spray chamber with the following parameters: 5% NaCl solution, temperature 35℃, relative humidity ≥95%. The single-sided corrosion width (mm) and blistering level at the scratch are observed every 240 hours, according to ASTM B117. The experiment is repeated for five groups, and the average value is taken.

[0095] Table 2: Adhesion Test Table for Waterborne Epoxy Primers

[0096]

[0097] The specific steps for the adhesion test are as follows:

[0098] The primers of Examples 2 and 3 and Comparative Examples 1 and 2 were uniformly applied to steel plates that had been sanded and cleaned. The coating thickness was 50 μm, the specified dry film thickness. The plates were dried and cured for 7 days at a temperature of 23±2℃ and a relative humidity of 50±5%. A cross-cut tester was used to make a grid on the coating surface with a grid spacing of 1 mm and a grid depth to the substrate, forming 10×10 small squares. The grid area was gently cleaned with a brush to remove coating debris. The tape was then flatly applied to the grid area and pressed firmly with the fingers to ensure full contact between the tape and the coating. After 1-2 minutes of applying the tape, the tape was quickly peeled off at a uniform speed and angle. The peeling of the coating in the grid area was observed with a magnifying glass. The adhesion grade was evaluated according to GB / T 9286-1998 "Cross-cut test of paint and varnish film". The lower the grade, the better the adhesion.

[0099] Prepare the same painted sample as for the adhesion test, and allow it to dry and cure for 7 days. Place the sample horizontally on the worktable of the pencil hardness tester. Select a pencil, sharpen the lead into a 5mm cylindrical shape, and smooth the end face of the lead with sandpaper. Install the pencil on the tester, making a 45° angle between the pencil and the sample surface. Gently touch the coating surface with the pencil tip and push the tester at a uniform speed, allowing the pencil to slide about 10mm across the coating surface. Erase the pencil marks with an eraser and observe whether there are any scratches on the coating surface. Start testing with the softest pencil and gradually increase the pencil hardness until scratches appear on the coating surface. Record the pencil hardness grade at this point and evaluate it according to the GB / T 6739-2006 standard "Determination of Hardness of Paints and Varnishes by Pencil Method".

[0100] Table 3: Water Resistance Test Table

[0101]

[0102] The water resistance test involved sandblasting a Q235 steel plate with dimensions of 150×70×1mm, applying a primer with a dry film thickness of 50±5μm, curing it at room temperature for 7 days, immersing it in deionized water at 40℃, observing the surface condition every 24 hours, and recording the time of blistering, whitening, and peeling of the coating.

[0103] Table 4: Settlement Stability Test Table

[0104]

[0105] The sedimentation stability was determined by loading the waterborne epoxy primers prepared in Examples 2 and 3 and Comparative Examples 1 and 2 into 250mL graduated cylinders, letting them stand at 25°C for 30 days, and then measuring the sedimentation rate.

[0106] Therefore, it can be seen that, compared with Comparative Examples 1 and 2, Examples 2 and 3 show a significantly longer salt spray resistance time. The enhanced anti-settling agent helps improve the corrosion resistance of the waterborne epoxy primer in high-salt and high-humidity environments. The enhanced anti-settling agent improves the microstructure of the primer, making the coating denser and reducing the penetration channels of corrosive media such as chloride ions in the salt spray. After modification with KH-560, the zirconium phosphosilicate powder forms a dense physical barrier in the coating, effectively blocking chloride ions. - penetration;

[0107] Meanwhile, the anti-settling agent helps to enhance the adhesion between the water-based epoxy primer and the substrate. Through synergistic effects with other components in the primer, it improves the wettability and adhesion of the primer, allowing the primer to adhere better to the substrate surface. The nanosheet structure of bentonite gel is oriented on the substrate surface, increasing the mechanical anchoring effect. At the same time, the bentonite gel network blocks capillary pores, preventing water molecule penetration while providing three-dimensional network support to resist gravity settling. The hydrophobic crystal structure of zirconium phosphosilicate reduces the water absorption rate of the coating.

[0108] In summary, this invention adds a reinforcing anti-settling agent to the raw materials of waterborne epoxy primers. The bentonite and modified zirconium phosphosilicate powder in the reinforcing anti-settling agent can improve the microstructure of the primer in the primer system, making the coating more dense. When the primer is applied to a high-salt and high-humidity environment, this dense structure can effectively reduce the penetration channels of corrosive media such as chloride ions in salt spray, enhance the salt spray resistance of waterborne epoxy primers, and improve their actual performance in harsh environments.

[0109] By reducing the water absorption rate of the coating through the hydrophobic crystal structure of zirconium phosphosilicate, an effective waterproof barrier is formed on the surface of the primer. When the primer comes into contact with water, the bentonite gel network blocks the capillary pores, preventing water molecules from penetrating and reducing water absorption, thereby improving the water resistance of the water-based epoxy primer, extending its water resistance time, and enhancing its functionality.

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments, characterized in that, The raw materials include the following parts by weight: 30-50 parts of bisphenol A type waterborne epoxy resin emulsion, 10-20 parts of curing agent T-31, 3.5-5 parts of reinforcing anti-settling agent, 8-12 parts of zinc phosphate, 5-8 parts of aluminum tripolyphosphate, 10-15 parts of precipitated barium sulfate, 3-6 parts of silica powder, 0.8-1.2 parts of sodium polyacrylate dispersant, 0.4-0.8 parts of silicone defoamer, 0.3-0.7 parts of acrylate leveling agent, and 0.6-1 part of polyurethane thickener; The enhanced anti-settling agent is prepared by the following steps: Step 1: Heat deionized water to 70°C and add it to the reactor. Start stirring and slowly add bentonite. Keep the temperature and continue stirring for 30 minutes until a uniform gel is formed to obtain the bentonite gel system. Step 2: In a separate container, mix KH-560 and ethanol at a mass ratio of 1:1 and hydrolyze for 10 minutes. Then add zirconium phosphosilicate powder and disperse at a high speed of 2000 rpm for 15 minutes to obtain modified powder. Add the modified powder to the bentonite gel system and switch to a high-speed homogenizer for further processing. During the processing, circulate the mixture through a colloid mill twice with a gap of 50 μm. Add deionized water and ammonia to adjust the pH to 9.0-10.0, so that the viscosity is 7500-8000 mPa·s, to obtain the enhanced anti-settling agent.

2. The heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments according to claim 1, characterized in that, The mass ratio of bentonite to deionized water used in step 1 is 1:

3. The stirring speed in step 1 is 600 r / min. The bentonite in step 1 is in solid granular form, with a particle size ≤80 mesh and an effective bentonite content ≥60%.

3. The heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments according to claim 1, characterized in that, The high-speed homogenizer used in step 2 has a rotation speed of 3000 r / min and a processing time of 20 minutes. The mass ratio of KH-560 to zirconium phosphosilicate powder in step 2 is 1:

6.

4. A production process for a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments as described in any one of claims 1-3, characterized in that, The preparation steps include the following: S1. Weigh the following raw materials according to the following mass percentages: the raw materials consist of 30-50 parts of bisphenol A type waterborne epoxy resin emulsion, 10-20 parts of curing agent T-31, 3.5-5 parts of reinforcing anti-settling agent, 8-12 parts of zinc phosphate, 5-8 parts of aluminum tripolyphosphate, 10-15 parts of precipitated barium sulfate, 3-6 parts of silica powder, 0.8-1.2 parts of sodium polyacrylate dispersant, 0.4-0.8 parts of silicone defoamer, 0.3-0.7 parts of acrylate leveling agent, and 0.6-1 parts of polyurethane thickener; S2. Add an appropriate amount of deionized water to the mixing tank, then add sodium polyacrylate dispersant and stir for 5-10 minutes to fully dissolve the dispersant in the deionized water. Then add zinc phosphate, aluminum tripolyphosphate, precipitated barium sulfate and silica powder while stirring. The feeding time should be controlled at 10-15 minutes. After the feeding is completed, increase the stirring speed and continue stirring for 20-30 minutes to make the pigments and fillers initially dispersed evenly, and obtain pre-dispersed material A. S3. Transfer the pre-dispersed material A to a sand mill, turn on the sand mill to grind, and circulate the grinding until the fineness of the pre-dispersed material A is ≤30μm to obtain the grinding material; S4. Return the grinding slurry to the dispersion tank, adjust the rotation speed to 400 r / min, and slowly add the anti-settling agent. Continue stirring for 15 minutes until the system shows a uniform blue-gray fluorescence. S5. Reduce the stirring speed and slowly add the bisphenol A type waterborne epoxy resin emulsion. After the addition is complete, continue stirring for 30-40 minutes. Then add the silicone defoamer and acrylate leveling agent in sequence. Stir for 5-10 minutes after each additive is added. Then dilute the polyurethane thickener with 3 times the amount of deionized water and slowly add it dropwise to adjust the viscosity to 85-90KU to obtain the semi-finished primer. S6. Mix the curing agent T-31 and deionized water in a container at a 1:1 ratio until homogeneous. Continue stirring and mixing. Slowly add the mixed curing agent solution to the semi-finished primer while stirring. The stirring speed is 100 r / min, and the addition time is controlled at 10-15 minutes. After the addition is complete, continue stirring to ensure that the curing agent and the semi-finished primer are fully mixed. Transfer the mixture to a vacuum degassing kettle for degassing and then filter it through a 200-mesh filter to obtain the finished primer.

5. The production process of a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments according to claim 4, characterized in that, The mass ratio of deionized water to sodium polyacrylate dispersant in S2 is 30:

1. The stirring speed after adding sodium polyacrylate dispersant is 100 r / min, and the stirring speed after adding material is 300 r / min.

6. The production process of a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments according to claim 4, characterized in that, The grinding feed flow rate in S3 is 18 L / min, and the grinding pressure is 1 MPa.

7. The production process of a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments according to claim 4, characterized in that, In step S5, the stirring speed is reduced to 200 r / min, and the feeding time for adding the bisphenol A type waterborne epoxy resin emulsion is 15 minutes.

8. The production process of a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments according to claim 4, characterized in that, The stirring speed of the curing agent T-31 and deionized water in S6 is 300 r / min, and the stirring time is 10 minutes. When the curing agent solution is added to the semi-finished primer, the stirring speed is 100 r / min. After the addition is completed, stirring continues for 20 minutes to ensure that the curing agent and the semi-finished primer are fully mixed and uniform. The parameters of the vacuum degassing kettle are -0.08 MPa and the degassing time is 15 minutes.

9. The production process of a heavy-duty anti-corrosion waterborne epoxy primer suitable for high-salt and high-humidity environments according to claim 4, characterized in that, The bisphenol A type waterborne epoxy resin emulsion used is E-44, the silica powder is 300 mesh, the silicone defoamer is BYK-028, the acrylate leveling agent is OP-8035, and the polyurethane thickener is PU-40.

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