A water-based epoxy glass flake heavy-duty anti-corrosion coating and its preparation method

Abstract

This invention relates to the field of coatings, specifically to a water-based epoxy glass flake heavy-duty anti-corrosion coating and its preparation method, comprising 11.5-12.5 parts water, 1-1.2 parts dispersant, 0.5-0.6 parts wetting and defoaming agent, 0.2-0.3 parts defoamer, 1.1-1.2 parts anti-settling agent, 49-51 parts water-based epoxy resin dispersion, 3-3.4 parts rust-inhibiting pigment, 30-36.5 parts graded glass flakes; 9.8-10.2 parts water-based amine copolymer, 1.3-1.4 parts flash rust inhibitor, and 1.5-2.5 parts water. This anti-corrosion coating contains no solvents and has low VOCs. The anti-corrosion performance of the coating can be improved by adding two rust-inhibiting pigments and fillers: aluminum tripolyphosphate, zinc strontium phosphate, and glass flakes. Neutral salt spray and seawater immersion tests showed that the coating film did not bubble, rust, or peel after 12,000 hours of immersion.

Description

Technical Field

[0001] This invention relates to the field of coatings, and more specifically, to a water-based epoxy glass flake heavy-duty anti-corrosion coating and its preparation method. Background Technology

[0002] With the rapid development of offshore oil and gas field exploration, wind power generation, and highways in my country, long-term corrosion protection of components such as drilling platforms, wind power facilities, and bridge steel structures is crucial, as it directly affects the service life of these facilities.

[0003] Currently, most anti-rust primers (coatings) are two-component epoxy zinc-rich primers and two-component epoxy glass flake paints (coatings). For example, the coating disclosed in patent CN202511094596.0 has a maximum salt spray resistance time of 6000 hours. It is a solvent-based two-component epoxy zinc-rich primer with high VOC content, which causes significant environmental pollution during construction.

[0004] Two-component epoxy glass flake paint (coating) is another long-lasting anti-corrosion coating. Compared with two-component epoxy zinc-rich primer, it has the advantages of lower cost, better construction efficiency, and a dry film thickness of 400-500 micrometers in a single application. The oil-based coating disclosed in patent CN201110282378.1 has a maximum salt spray resistance time of 5000 hours, but it also has the disadvantages of high VOC content and significant environmental pollution during construction. Summary of the Invention

[0005] The purpose of this invention is to provide a water-based epoxy glass flake heavy-duty anti-corrosion coating, which has the advantages of high construction efficiency, a dry film thickness of 500um without sagging, better rust prevention effect, and no blistering, rusting and peeling of the paint film in seawater and neutral salt spray tests for 12,000 hours.

[0006] The technical problem solved by this invention is achieved by the following technical solution.

[0007] On one hand, embodiments of the present invention provide a water-based epoxy glass flake heavy-duty anti-corrosion coating, comprising component A and component B, wherein the mass ratio of component A to component B is 7.5:1; Component A comprises the following raw materials by weight: 49-51 parts of waterborne epoxy resin dispersion, 1-1.2 parts of dispersant, 0.5-0.6 parts of wetting and defoaming agent, 1.1-1.2 parts of anti-settling agent, 3-3.4 parts of anti-rust pigment, 11.5-12.5 parts of water, 30-36.5 parts of graded glass flakes, and 0.2-0.3 parts of defoamer; Component B comprises the following raw materials by weight: 9.8-10.2 parts of water-based amine copolymer, 1.3-1.4 parts of flash rust inhibitor, and 1.5-2.5 parts of water.

[0008] In some embodiments of the present invention, the anti-rust pigment is at least one of aluminum tripolyphosphate and zinc strontium phosphate.

[0009] In some embodiments of the present invention, the anti-rust pigment comprises, by weight, 1.9-2.1 parts aluminum tripolyphosphate and 1.1-1.3 parts zinc strontium phosphate.

[0010] In some embodiments of the present invention, the aqueous epoxy dispersion is a bisphenol A epoxy resin dispersion with an epoxy equivalent of 900-1200 g / mol.

[0011] In some embodiments of the present invention, the wetting and defoaming agent is an acetylenic diol wetting and defoaming agent; the anti-settling agent is fumed silica; and the defoaming agent is an organosilicon defoaming agent.

[0012] In some embodiments of the present invention, the hydrogen equivalent of the aqueous amine copolymer is 200-250 g / mol.

[0013] In some embodiments of the present invention, the flash rust inhibitor is a mixture of 30% sodium nitrite solution and organic rust inhibitor in a mass ratio of 1:3.

[0014] In some embodiments of the present invention, the graded glass flakes, by weight, comprise: 14-15 parts of 20-mesh glass flakes, 8-10 parts of 40-mesh glass flakes, 5-7 parts of 60-mesh glass flakes, 2-3 parts of 120-mesh glass flakes, and 1-1.5 parts of 300-mesh glass flakes.

[0015] In some embodiments of the present invention, the dispersant is a nonionic dispersant.

[0016] A method for preparing a water-based epoxy glass flake heavy-duty anti-corrosion coating includes the following steps: First, add water to the dispersion tank. Under medium-speed stirring, add a portion of epoxy dispersion, dispersant, wetting and defoaming agent, silicone defoamer, and anti-settling agent in sequence. Then stir at high speed. When the fineness reaches below 40 microns, add the remaining component A raw material in sequence. Stir at medium speed until the mixture is uniform to obtain slurry A. Mix the raw materials of component B and stir at medium speed until homogeneous to obtain curing agent B; Mix slurry A and curing agent B in the specified proportions and stir until homogeneous to obtain the coating.

[0017] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: The anti-corrosion coating provided by this invention contains no solvents and has low VOCs. By adding two rust-inhibiting pigments, aluminum tripolyphosphate and zinc strontium phosphate, instead of a single rust-inhibiting pigment, the two pigments synergistically passivate the metal surface and form an effective barrier layer to improve the rust-inhibiting effect. Our comparative experiments have demonstrated that the two rust-inhibiting pigments provide better rust prevention than aluminum tripolyphosphate or zinc strontium phosphate alone. By adding relatively coarse glass flakes (20 mesh, 40 mesh, 60 mesh, etc.) and a small amount of fine (120 mesh and 300 mesh) glass flakes, not only is the efficiency of application spraying improved, achieving a dry film thickness of 400-500 micrometers in a single spray, but the rust-inhibiting effect of epoxy glass flake anti-rust primer is also greatly improved, surpassing the anti-corrosion effect of previously reported epoxy primers (including zinc-rich and glass flake primers). The coating film formed by this invention has been tested in neutral salt spray and seawater immersion experiments, achieving a duration of 12,000 hours without blistering, rusting, or peeling.

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will provide further explanation using a list of experimental data. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to specific embodiments.

[0021] This invention provides a water-based epoxy glass flake heavy-duty anti-corrosion coating, comprising component A and component B, wherein the mass ratio of component A to component B is 7.5:1; Component A comprises the following raw materials by weight: 49-51 parts of waterborne epoxy resin dispersion, 1-1.2 parts of dispersant, 0.5-0.6 parts of wetting and defoaming agent, 1.1-1.2 parts of anti-settling agent, 3-3.4 parts of anti-rust pigment, 11.5-12.5 parts of water, 30-36.5 parts of graded glass flakes, and 0.2-0.3 parts of defoamer; The graded glass flakes include: 14-15 parts of 20-mesh glass flakes, 8-10 parts of 40-mesh glass flakes, 5-7 parts of 60-mesh glass flakes, 2-3 parts of 120-mesh glass flakes, and 1-1.5 parts of 300-mesh glass flakes.

[0022] Component B comprises the following raw materials by weight: 9.8-10.2 parts of water-based amine copolymer, 1.3-1.4 parts of flash rust inhibitor, and 1.5-2.5 parts of water.

[0023] The rust-preventive pigment is a mixture of aluminum tripolyphosphate and zinc strontium phosphate. By weight, the rust-preventive pigment comprises 1.9-2.1 parts aluminum tripolyphosphate and 1.1-1.3 parts zinc strontium phosphate.

[0024] Aluminum tripolyphosphate and zinc strontium phosphate work synergistically to passivate metal surfaces, forming an effective shielding layer to improve rust prevention.

[0025] The aqueous epoxy dispersion is a bisphenol A epoxy resin dispersion with an epoxy equivalent of 900-1200 g / mol. The wetting and defoaming agent is an acetylenic glycol wetting and defoaming agent; the anti-settling agent is fumed silica; and the defoamer is an organosilicon defoamer. Based on a 100% solid content of the aqueous amine copolymer, the hydrogen equivalent of the aqueous amine copolymer is 240-250 g / mol. The flash rust inhibitor is a mixture of a 30% (w / w) sodium nitrite solution and an organic rust inhibitor, with a mass ratio of 1:3.

[0026] Glass flakes of different particle sizes are used in different mass ratios. This gradation combination and the layered structure of the glass flakes can eliminate microscopic gaps in the paint film formation process, prevent water molecules and various anions in the environmental medium from penetrating through the paint film and reaching the surface of the steel substrate, and prevent the formation of corrosion spots.

[0027] In some embodiments of the present invention, the dispersant is a commercially available nonionic dispersant that can be purchased directly from the market.

[0028] A method for preparing a water-based epoxy glass flake heavy-duty anti-corrosion coating includes the following steps: First, add water to the dispersion tank. Under medium-speed stirring, add a portion of epoxy dispersion, dispersant, wetting and defoaming agent, silicone defoamer, and anti-settling agent in sequence. Then stir at high speed. When the fineness reaches below 40 microns, add the remaining component A raw material in sequence. Stir at medium speed until the mixture is uniform to obtain slurry A. Mix the raw materials of component B and stir at medium speed until homogeneous to obtain curing agent B; Mix slurry A and curing agent B in the specified proportions and stir until homogeneous to obtain the coating.

[0029] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0030] Example Prepare the raw materials for component A according to the raw material ratios in Table 1: In the six different formulations in Table 1, the preparation method is as follows: First, add raw material No. 1 into the dispersion tank, then add 9 parts of raw material No. 6 and raw materials No. 2-5 in sequence under medium speed stirring, then disperse at high speed until the fineness reaches below 40 μm, then add raw materials No. 6-14 in sequence under medium speed stirring, stir evenly, and obtain slurry A.

[0031] Table 1

[0032] In Table 1, the nonionic dispersant is MixSperse 855W water-based wetting and dispersing agent from Wuxi Mixos New Material Technology Co., Ltd.

[0033] The wetting and defoaming agent is acetylenic diol wetting and defoaming agent, derived from Air Chemical's 104E.

[0034] The silicone defoamer is from Digo's 810.

[0035] The anti-settling agent is fumed silica, from Evonik's 974.

[0036] The aqueous epoxy dispersion is a bisphenol A epoxy resin dispersion with an epoxy equivalent of 900-1200 g / mol in the supplied state. It is product 3EE104W from Guangdong Di'aisheng Tongde Resin Co., Ltd.

[0037] Component B: 10 parts amine copolymer, 1.3 parts flash rust inhibitor, and 2 parts water. Mix the above three raw materials at medium speed in a dispersion tank to obtain curing agent B, i.e., the curing agent component.

[0038] The amine copolymer is EH3504 from Guangdong Qirun New Materials Co., Ltd., with an active hydrogen equivalent of 247 g / mol. The flash rust inhibitor is a mixture of 30% sodium nitrite solution and liquid organic rust inhibitor in a mass ratio of 1:3. The liquid organic rust inhibitor is HALOX®515 from Jinhui Chemical.

[0039] Mix the slurry A part and the curing agent B part at a mass ratio of 7.5:1 and stir evenly to obtain the coating.

[0040] The steel plates used for neutral salt spray and brine tests are all cold-rolled carbon steel plates. The above coating is sprayed twice onto the cold-rolled carbon steel plates, with a dry film thickness of 480-530 μm. After spraying, the plates are left at room temperature for 2 days, and then subjected to 80°C... 0 Bake in oven C for 2 hours, then cool before starting the experiment.

[0041] From the data in Table 1 regarding resistance to neutral salt spray and seawater immersion, it can be seen that: Sample 1 exhibited the longest resistance to neutral salt spray and seawater immersion tests, lasting up to 12,000 hours, without rusting, blistering, or peeling. This is attributed to the addition of aluminum tripolyphosphate and zinc strontium phosphate, two rust-preventive pigments, which synergistically passivate the metal surface, forming an effective shielding layer to enhance rust prevention. Furthermore, Sample 1 incorporated coarser glass flakes of 20, 40, and 60 mesh, as well as finer glass flakes of 120 and 300 mesh. The amount of glass flakes of different particle sizes gradually decreased, ultimately using only a small amount of 120 and 300 mesh fine glass flakes. This graded distribution of glass flakes eliminated microscopic channels during the film formation process, preventing water molecules and various anions in the environment from penetrating the film and reaching the steel substrate surface, thus preventing corrosion.

[0042] With all other components remaining unchanged, adding aluminum tripolyphosphate as the rust-inhibiting pigment to sample 2 and zinc strontium phosphate as the rust-inhibiting pigment to sample 3 reduced the time for both the neutral salt spray test and the seawater test by about 6000 hours, indicating that the synergistic effect of the two rust-inhibiting pigments is very obvious.

[0043] With all other components unchanged, Sample 4, without the addition of 20-mesh glass flakes, used only combinations of 40-mesh, 60-mesh, 120-mesh, and 300-mesh glass flakes. The neutral salt spray resistance test time was reduced to about 3000 hours, and the seawater resistance test time was reduced to about 3200 hours. This indicates that the coarse 20-mesh glass flakes played a decisive role in blocking the penetration of medium particles into the paint film.

[0044] With all other components unchanged, sample 5, without adding 20-mesh and 40-mesh glass flakes, and only using a combination of 60-mesh, 120-mesh and 300-mesh glass flakes, reduced the neutral salt spray resistance test time to about 400 hours and the seawater resistance test time to about 400 hours, indicating that the sealing performance of the paint film is very poor without coarse glass flakes.

[0045] With all other components unchanged, sample 7 did not contain 20-mesh, 40-mesh, and 60-mesh glass flakes, but only used 120-mesh and 300-mesh glass flakes. Even with a dry film thickness of only 80 μm, the film cracked during the film formation process and could not form an effective continuous paint film, making it impossible to conduct accelerated corrosion tests.

[0046] Based on Sample 1, Sample 6 replaced the 300-mesh glass flakes with an equal amount of titanium dioxide. The salt spray test time was reduced to about 4500 hours, and the seawater resistance test time was reduced to about 4800 hours. This shows that even a small amount of spherical titanium dioxide can create tiny channels during the coating film formation process, which greatly reduces the time for various accelerated corrosion processes.

[0047] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A water-based epoxy glass flake heavy-duty anti-corrosion coating, characterized in that, It includes component A and component B, with a mass ratio of component A to component B of 7.5:1; Component A comprises the following raw materials by weight: 11.5-12.5 parts water, 1-1.2 parts dispersant, 0.5-0.6 parts wetting and defoaming agent, 0.2-0.3 parts defoamer, 1.1-1.2 parts anti-settling agent, 49-51 parts waterborne epoxy resin dispersion, 3-3.4 parts rust-preventive pigment, and 30-36.5 parts graded glass flakes; Component B comprises the following raw materials by weight: Waterborne amine copolymer 9.8-10.2, flash rust inhibitor 1.3-1.4 parts, water 1.5-2.5 parts.

2. The water-based epoxy glass flake heavy-duty anti-corrosion coating according to claim 1, characterized in that, The rust-preventive pigment is a mixture of aluminum tripolyphosphate and zinc strontium phosphate.

3. The water-based epoxy glass flake heavy-duty anti-corrosion coating according to claim 2, characterized in that, The rust-preventive pigment comprises 1.9-2.1 parts aluminum tripolyphosphate and 1.1-1.3 parts zinc strontium phosphate by weight.

4. The water-based epoxy glass flake heavy-duty anti-corrosion coating according to claim 1, characterized in that, The aqueous epoxy dispersion is a bisphenol A epoxy resin dispersion with an epoxy equivalent of 900-1200 g / mol.

5. The water-based epoxy glass flake heavy-duty anti-corrosion coating according to claim 1, characterized in that, The wetting and defoaming agent is acetylenic diol wetting and defoaming agent; the anti-settling agent is fumed silica; and the defoaming agent is organosilicon defoaming agent.

6. The water-based epoxy glass flake heavy-duty anti-corrosion coating according to claim 1, characterized in that, Based on a solid content of 100% for the waterborne amine copolymer, the active hydrogen equivalent of the waterborne amine copolymer is 240-250 g / mol.

7. The water-based epoxy glass flake heavy-duty anti-corrosion coating according to claim 1, characterized in that, The flash rust inhibitor is a mixture of 30% sodium nitrite solution and liquid organic rust inhibitor, with a mass ratio of 1:

3.

8. The water-based epoxy glass flake heavy-duty anti-corrosion coating according to claim 1, characterized in that, By weight, the graded glass flakes include: 14-15 parts of 20-mesh glass flakes, 8-10 parts of 40-mesh glass flakes, 5-7 parts of 60-mesh glass flakes, 2-3 parts of 120-mesh glass flakes, and 1-1.5 parts of 300-mesh glass flakes.

9. The water-based epoxy glass flake heavy-duty anti-corrosion coating according to claim 1, characterized in that, The dispersant is a nonionic dispersant.

10. A method for preparing a waterborne epoxy glass flake heavy-duty anti-corrosion coating as described in any one of claims 1-9, characterized in that, Includes the following steps: First, add water to the dispersion tank. Under medium-speed stirring, add a portion of epoxy dispersion, dispersant, wetting and defoaming agent, silicone defoamer, and anti-settling agent in sequence. Then stir at high speed. When the fineness reaches below 40 microns, add the remaining component A raw material in sequence. Stir at medium speed until the mixture is uniform to obtain slurry A. Mix the raw materials of component B and stir at medium speed until homogeneous to obtain curing agent B; Mix slurry A and curing agent B in the specified proportions and stir until homogeneous to obtain the coating.

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