A waterborne epoxy primer, its preparation method and application

Abstract

The present application belongs to the technical field of paint, and particularly relates to a water-based epoxy primer, a preparation method and application thereof. The water-based epoxy primer comprises component A and component B; the component A comprises a water-based epoxy resin, a first additive, a pigment filler and water; the component B comprises a water-based epoxy curing agent, a second additive and water; the water-based epoxy resin comprises an epoxy resin with an epoxy equivalent of 700-900 g / mol and an epoxy resin with an epoxy equivalent of 2800-4200 g / mol; and the water-based epoxy curing agent has an active hydrogen equivalent of 120-250 g / Eq. The water-based epoxy primer has good early water resistance, long-term heavy corrosion resistance, harsh environment recovery and good anti-flash rust resistance by using the water-based epoxy resin with an epoxy equivalent of 700-900 g / mol and the water-based epoxy resin with an epoxy equivalent of 2800-4200 g / mol in combination with the water-based epoxy curing agent with an active hydrogen equivalent.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, and specifically relates to a water-based epoxy primer, its preparation method, and its application. Background Technology

[0002] Waterborne two-component epoxy primers have become key primers in steel structure anti-corrosion systems due to their excellent adhesion, chemical resistance, and anti-corrosion performance. Meanwhile, as a core material in the construction of infrastructure such as buildings, bridges, and factories, long-term anti-corrosion is crucial to ensuring structural safety and lifespan.

[0003] Despite the significant advantages of water-based two-component epoxy primers in terms of performance and environmental friendliness, their practical application and promotion still face numerous challenges, especially in steel structure engineering where construction conditions and efficiency requirements are extremely high. The on-site environment for steel structure coating is complex and variable. Existing water-based two-component epoxy primers have not yet established their initial properties approximately 24 hours after application, exhibiting extremely poor water resistance. If a sudden downpour occurs at this time, the paint film may experience irreversible flash rust, whitening, or even peeling during condensation, leading to project delays or claims and causing substantial economic losses.

[0004] Currently, water-based anti-corrosion primers for steel structures mainly include water-based alkyd, water-based one-component acrylic, and water-based two-component epoxy. Water-based alkyd and water-based one-component acrylic are easy to apply and have good initial water resistance, but their anti-corrosion performance is generally average. Water-based two-component epoxy primers have excellent adhesion, chemical resistance, and anti-corrosion performance, but their cross-linking speed is slow, requiring sufficient film-forming time to establish initial properties.

[0005] Therefore, it is of great significance to provide a water-based epoxy primer with good early water resistance, long-lasting heavy corrosion protection, and recovery in harsh environments. Summary of the Invention

[0006] The present invention aims to solve one or more technical problems existing in the prior art, and at least provide a beneficial alternative. Specifically, the present invention provides a water-based epoxy primer that has good early water resistance, long-term heavy corrosion protection, and good recovery in harsh environments, that is, it does not flash rust in long-term high humidity (≥90%RH, 16h) environment, and its adhesion can recover to ≤1 level within 24h.

[0007] The inventive concept of this invention: The waterborne epoxy primer of this invention comprises component A and component B; component A comprises waterborne epoxy resin, a first additive, pigments and fillers, and water; component B comprises waterborne epoxy curing agent, a second additive, and water; the waterborne epoxy resin comprises epoxy resin with an epoxy equivalent of 700-900 g / mol and epoxy resin with an epoxy equivalent of 2800-4200 g / mol; the waterborne epoxy curing agent has an active hydrogen equivalent of 120-250 g / Eq.

[0008] In this invention, epoxy resin with an epoxy equivalent of 2800-4200 g / mol is used as the core film-forming material, exhibiting good drying performance and providing excellent initial performance and high humidity recovery capability. Epoxy resin with an epoxy equivalent of 700-900 g / mol possesses good film-forming properties and low-temperature (5°C) film-forming ability, and can provide mid-term or late-term corrosion protection. By using a composite of epoxy resins with an epoxy equivalent of 700-900 g / mol and epoxy resins with an epoxy equivalent of 2800-4200 g / mol, combined with a waterborne epoxy curing agent with a specific active hydrogen equivalent, the waterborne epoxy primer simultaneously possesses good early water resistance, early water and rain resistance, long-term heavy-duty corrosion protection, and recovery in harsh environments, effectively solving the problem of insufficient initial performance.

[0009] Therefore, a first aspect of the present invention provides a waterborne epoxy primer.

[0010] Specifically, the waterborne epoxy primer includes component A and component B; Component A includes waterborne epoxy resin, a first additive, pigments and fillers, and water. Component B includes an aqueous epoxy curing agent, a second auxiliary agent, and water; The waterborne epoxy resin includes epoxy resin with an epoxy equivalent of 700-900 g / mol and epoxy resin with an epoxy equivalent of 2800-4200 g / mol. The active hydrogen equivalent of the waterborne epoxy curing agent is 120-250 g / Eq.

[0011] Preferably, the epoxy resin with an epoxy equivalent of 700-900 g / mol is selected from at least one of Guangzhou Lingwei JT-WBE518 and JT-WBE527; the epoxy resin with an epoxy equivalent of 2800-4200 g / mol is selected from Guangzhou Lingwei JT-WBE550.

[0012] Preferably, the waterborne epoxy curing agent is a fast-drying waterborne epoxy curing agent, selected from at least one of Guangzhou Lingwei JT-WBH823, Guangzhou Lingwei JT-WBH820, and BECKOPOX™ EH 613w 80WA.

[0013] Preferably, by mass, component A comprises 40-60 parts of waterborne epoxy resin, 2.4-10.2 parts of first additive, 17-43 parts of pigments and fillers, and 10-20 parts of water.

[0014] Preferably, component B comprises 1-5 parts of water-based epoxy curing agent, 0.5-6.5 parts of second auxiliary agent, and 2-10 parts of water.

[0015] Preferably, the first additive includes at least one of film-forming aid, anti-settling agent, wetting and dispersing agent, defoamer, substrate wetting agent, adhesion promoter, and thickener.

[0016] Preferably, the pigments and fillers include rust-preventive pigments and fillers.

[0017] Preferably, the second additive includes at least one of a co-solvent and an anti-flash rust agent.

[0018] Preferably, by weight, component A comprises 40-60 parts of waterborne epoxy resin, 2-8 parts of anti-rust pigment, 15-35 parts of filler, 1-4 parts of film-forming aid, 0.1-0.5 parts of anti-settling agent, 0.5-2 parts of wetting and dispersing agent, 0.1-0.5 parts of defoamer, 0.1-0.7 parts of substrate wetting agent, 0.1-0.5 parts of adhesion promoter, 0.5-2.0 parts of thickener, and 10-20 parts of water.

[0019] Preferably, part B comprises 1-5 parts of water-based epoxy curing agent, 0-5 parts of co-solvent, 0.5-1.5 parts of anti-flash rust agent, and 2-10 parts of water.

[0020] Preferably, the waterborne epoxy primer comprises component A and component B; by weight, component A comprises 40-60 parts waterborne epoxy resin, 2-8 parts anti-rust pigment, 15-35 parts filler, 1-4 parts film-forming aid, 0.1-0.5 parts anti-settling agent, 0.5-2 parts wetting and dispersing agent, 0.1-0.5 parts defoamer, 0.1-0.7 parts substrate wetting agent, 0.1-0.5 parts adhesion promoter, 0.5-2.0 parts thickener, and 10-20 parts water; component B comprises 1-5 parts waterborne epoxy curing agent, 0-5 parts co-solvent, 0.5-1.5 parts anti-flash rust agent, and 2-10 parts water.

[0021] Preferably, the rust-preventive pigment includes phosphate-based rust-preventive pigments; more preferably, the phosphate-based rust-preventive pigment includes at least one of zinc phosphate, zinc aluminum phosphate, aluminum tripolyphosphate, and zinc strontium phosphate; for example, at least one of Guangxi Chemical Research Institute APW-II, He Sanhong SHA218, SHA4, Hangzhou STENICPHOS ZA, STENICPHOS 222, and Shanghai Junjiang JP-808.

[0022] Preferably, the filler includes at least one of titanium dioxide, precipitated barium sulfate, talc powder, mica powder, silica powder, feldspar powder, wollastonite, and carbon black.

[0023] Preferably, the wetting and dispersing agent comprises a polymeric block graft copolymer; for example, at least one selected from Polywill® D-6390 wetting and dispersing agent, BYK 190, BYK 194N, TEGO 757W, and ALLNEX 6208.

[0024] Preferably, the defoamer includes at least one of silicone defoamer, mineral oil defoamer, and acetylenic diol defoamer.

[0025] Specifically, the defoamer is an aqueous defoamer, for example, an aqueous defoamer selected from at least one of TEGO® Airex 901 W, TEGO® Airex 902 W, TEGO® Foamex 810, TEGO® Foamex 845, SURFYNOL® 104E, and Silok® 4630.

[0026] Preferably, the anti-settling agent includes at least one of bentonite and fumed silica; for example, at least one selected from Zhejiang Huatai BP-LT, BP-188L, BP-652, and EVONIK AEROSIL® 200.

[0027] Preferably, the film-forming aid comprises an alcohol ether solvent; more preferably, the film-forming aid comprises at least one of dipropylene glycol butyl ether (DPNB), propylene glycol methyl ether (PM), dipropylene glycol methyl ether (DPM), propylene glycol butyl ether (PNB), ethylene glycol butyl ether (BCS), and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (dodecyl alcohol ester).

[0028] Preferably, the thickener comprises a polyurethane thickener; more preferably, the polyurethane thickener comprises at least one of a medium shear rate thickener, a medium-low shear rate thickener, and a low shear rate thickener, for example, at least one selected from RHEOLATE® 299, RHEOLATE® 105A, and Borchi® Gel 0620.

[0029] Preferably, the substrate wetting agent is selected from at least one of TEGO 270, BYK 346, BYK 348, EVONIK TWIN 4000, and EVONIK TWIN 4100.

[0030] Preferably, the adhesion promoter comprises CoatOSil MP200.

[0031] Preferably, the co-solvent includes an alcohol ether solvent; more preferably, the co-solvent includes at least one of propylene glycol methyl ether, dipropylene glycol methyl ether, and ethylene glycol butyl ether.

[0032] Preferably, the anti-flash rust agent is selected from at least one of Shandong Enze HY78, Halox Raybo 60, NALZIN® FA17, and Shanghai Junjiang JP-W6185 anti-flash rust agents.

[0033] Preferably, the mass ratio of component A to component B is (8-20):1; for example, the mass ratio is 20:1, 10:1, 8:1, etc.

[0034] A second aspect of the present invention provides a method for preparing the waterborne epoxy primer described in the first aspect of the present invention.

[0035] Specifically, the preparation method of the waterborne epoxy primer includes the following steps: The raw material components of component A are mixed to obtain component A; The raw material components of component B are mixed to obtain component B; The components A and B constitute the waterborne epoxy primer.

[0036] Preferably, the preparation process of component A includes the following steps: Water, wetting and dispersing agent, some defoamer, anti-settling agent, rust-preventing pigment, and filler are mixed, stirred and dispersed, and ground to obtain a slurry; Waterborne epoxy resin, film-forming aid, and the remaining amount of defoamer, adhesion promoter, and substrate wetting agent are added to the slurry. Finally, a thickener is added to adjust the viscosity to obtain component A.

[0037] Preferably, the stirring and dispersing speed is 600-800 rpm, and the stirring and dispersing time is 25-35 min.

[0038] Preferably, the material is ground to a fineness of ≤30μm using a grinder before being discharged to obtain a slurry.

[0039] Preferably, the waterborne epoxy resin, film-forming aid, and the remaining defoamer, adhesion promoter, substrate wetting agent, and thickener are added while stirring.

[0040] Preferably, the preparation process of component B includes the following steps: The water-based epoxy curing agent, co-solvent, anti-flash rust agent and water are mixed, stirred and dispersed to obtain the material.

[0041] Preferably, during the preparation of component B, the stirring and dispersion speed is 400-600 rpm, and the stirring and dispersion time is 25-35 min.

[0042] A third aspect of the present invention provides an application of the waterborne epoxy primer described in the first aspect of the present invention in steel structure engineering.

[0043] Specifically, the waterborne epoxy primer of this invention has good early water resistance, long-lasting heavy corrosion protection, and resilience in harsh environments, providing a reliable and efficient waterborne anti-corrosion coating for steel structures, which can effectively cope with the complex and variable environment encountered in the actual outdoor construction of steel structures.

[0044] Compared with the prior art, the beneficial effects of the technical solution provided by the present invention are as follows: This invention employs a composite of epoxy resins with an epoxy equivalent of 700-900 g / mol and epoxy resins with an epoxy equivalent of 2800-4200 g / mol, combined with a waterborne epoxy curing agent with a specific active hydrogen equivalent. This synergistic effect results in a waterborne epoxy primer that exhibits excellent early water resistance (no rust or blistering after 2 hours of self-drying and immersion in water for ≥240 hours); excellent early water and rain resistance (resisting continuous water flow after 2 hours of self-drying); excellent long-term heavy-duty corrosion protection (no rust or blistering after more than 500 hours of salt spray testing); and excellent resilience in harsh environments (no flash rust under prolonged high humidity (≥90%RH, 16 hours), with adhesion recovering to Grade 1 within 24 hours and excellent resistance to flash rust. It can solve the problems of slow initial performance development of conventional water-based epoxy primers, which easily leads to blistering or corrosion in water resistance tests; it can solve the problems of failure to form a film or poor adhesion after long-term high humidity curing of conventional water-based epoxy primers; and it can solve the problem of poor anti-corrosion performance caused by mixing water-based epoxy primers with single-component acrylic emulsions.

[0045] This invention effectively addresses the variable environments that may be encountered during outdoor construction of large structural components such as steel structures. In particular, it solves the problem of blistering and corrosion caused by rain after water-based epoxy system application, before the initial performance of the paint film has been established, thus requiring rework. It can improve construction efficiency and reduce construction costs and risks. Detailed Implementation

[0046] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0047] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0048] Example 1 This embodiment provides a waterborne epoxy primer, which is composed of component A and component B in a mass ratio of 10:1; Component A consists of the following parts by weight of raw materials: 17.35 parts deionized water Wetting and dispersing agent (Polywill® D-6390) 0.60 parts Mineral oil defoamer (Silok® 4630) 0.20 parts Anti-settling agent (Zhejiang Huatai BP-LT) 0.10 parts Rust-preventive pigment (Guangxi Chemical Research Institute APW-II) 2.00 parts Rust-preventive pigment (Shanghai Junjiang JP-808) 1.50 parts Filler titanium dioxide (DuPont® R706) 2.00 parts 0.15 parts of filler (Mitsubishi MA100 carbon black from Japan) 8.00 parts of filler (Henan Baifeng N98 precipitated barium sulfate) Filler (Gree GA-4 mica powder) 5.00 parts 12.50 parts of filler (Gree silica micro powder) Filler (Jiangxi Guangyuan Wollastonite) 5.00 parts Waterborne epoxy resin (Guangzhou Lingwei JT-WBE550) 32.00 parts 10.00 parts of waterborne epoxy resin (Guangzhou Lingwei JT-WBE518) Film-forming aid, dodecyl alcohol ester, 1.20 parts 0.20 parts of water-based defoamer (TEGO® Airex 902 W) Substrate wetting agent (EVONIK Twin 4100) 0.10 parts Adhesion promoter (CoatOSil MP200) 0.30 parts 1.50 parts of polyurethane thickener (Borchi® Gel 0620) 0.30 parts deionized water; Component B consists of the following parts by weight of raw materials: Water-based epoxy curing agent (Guangzhou Lingwei JT-WBH823) 2.45 parts 2.00 parts of cosolvent propylene glycol methyl ether Anti-flash rust agent (Halox Raybo 60) 0.50 parts Anti-flash rust agent (Shandong Enze HY78) 0.50 parts 4.55 parts deionized water.

[0049] This embodiment also provides a method for preparing the above-mentioned waterborne epoxy primer, the specific steps of which are as follows: 17.35 parts of deionized water, wetting and dispersing agent, mineral oil defoamer, anti-settling agent, rust-preventing pigment, and filler were added to a dispersion tank and stirred at 700 rpm for 30 minutes. The mixture was then ground in a horizontal mill until the fineness was ≤30μm before being discharged to obtain a wet-milled slurry. The wet-milled slurry was added to a dispersion tank, and while stirring, waterborne epoxy resin, film-forming aid, waterborne defoamer TEGO® Airex 902 W, adhesion promoter, substrate wetting agent, and 0.3 parts of deionized water were added in sequence. Finally, while stirring, polyurethane thickener was added to adjust the viscosity. The fineness was tested to be ≤40μm, and the mixture was discharged to obtain component A. Add the water-based epoxy curing agent to the dispersion tank, and add the co-solvent, anti-flash rust agent and deionized water in sequence while stirring. Stir at 500 rpm for 30 min. Test the fineness to be ≤40μm, and discharge the material to obtain component B. Component A and Component B constitute a water-based epoxy primer.

[0050] Example 2 This embodiment provides a waterborne epoxy primer, which is composed of component A and component B in a mass ratio of 10:1; Component A consists of the following parts by weight of raw materials: 17.35 parts deionized water Wetting and dispersing agent (Polywill® D-6390) 0.60 parts Mineral oil defoamer (Silok® 4630) 0.20 parts Anti-settling agent (Zhejiang Huatai BP-LT) 0.10 parts Rust-preventive pigment (Guangxi Chemical Research Institute APW-II) 2.00 parts Rust-preventive pigment (Shanghai Junjiang JP-808) 1.50 parts Filler titanium dioxide (DuPont® R706) 2.00 parts 0.15 parts of filler (Mitsubishi MA100 carbon black from Japan) 8.00 parts of filler (Henan Baifeng N98 precipitated barium sulfate) Filler (Gree GA-4 mica powder) 5.00 parts 12.50 parts of filler (Gree silica micro powder) Filler (Jiangxi Guangyuan Wollastonite) 5.00 parts Waterborne epoxy resin (Guangzhou Lingwei JT-WBE550) 32.00 parts 10.00 parts of waterborne epoxy resin (Guangzhou Lingwei JT-WBE527) Film-forming aid, dodecyl alcohol ester, 1.20 parts 0.20 parts of water-based defoamer (TEGO® Airex 902 W) Substrate wetting agent (EVONIK Twin 4100) 0.10 parts Adhesion promoter (CoatOSil MP200) 0.30 parts 1.50 parts of polyurethane thickener (Borchi® Gel 0620) 0.30 parts deionized water; Component B consists of the following parts by weight of raw materials: Water-based epoxy curing agent (Guangzhou Lingwei JT-WBH823) 2.56 parts 2.00 parts of cosolvent propylene glycol methyl ether Anti-flash rust agent (Halox Raybo 60) 0.50 parts Anti-flash rust agent (Shandong Enze HY78) 0.50 parts 4.44 parts of deionized water.

[0051] Example 2: The preparation method of the waterborne epoxy primer is the same as that of Example 1.

[0052] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the waterborne epoxy resin in Comparative Example 1 is replaced by Guangzhou Lingwei JT-WBE521 (epoxy equivalent of 900-1300 g / mol) in an equal amount with the waterborne epoxy resins Guangzhou Lingwei JT-WBE550 and JT-WBE518 in Example 1. Otherwise, they are the same as in Example 1.

[0053] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the waterborne epoxy resin in Comparative Example 2 is replaced by an equal amount of Guangzhou Lingwei JT-WBE550 instead of JT-WBE518 in Example 1, i.e., it does not contain JT-WBE518. Everything else is the same as in Example 1.

[0054] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that the waterborne epoxy curing agent in Comparative Example 3 is replaced with an equal molar amount of Guangzhou Lingwei JT-WBH816 (active hydrogen equivalent 350g / Eq) instead of JT-WBH23 in Example 1, i.e. it does not contain JT-WBH23. Otherwise, it is the same as Example 1.

[0055] Performance testing Components A and B of the waterborne epoxy primers in Examples 1-2 and Comparative Examples 1-3 were mixed evenly according to their mass ratio, and 8% (by weight of component A) of deionized water was added. The mixtures were then sprayed onto substrates, and their performance was tested. The test items and methods are as follows: Film thickness: Dry film thickness 55±5μm, tested according to GB / T 13452.2-2008; Initial water resistance: After spraying, allow to air dry at 23±2 for 2 hours, and then test according to GB / T 1733, i.e., immerse in tap water at room temperature and observe blistering and corrosion. Early water resistance and rain resistance: After spraying, the sample was air-dried at 23±2 for 2 hours. Tap water was splashed onto the test sample, and after 16 hours it was dried. The color change of the sample surface was observed to simulate the early performance in response to severe rainy weather. Anti-flash rust performance: After the substrate is sprayed, it is immediately placed in a covered square water tank and the ambient humidity is kept ≥90%. The film formation is simulated in a closed environment with long-term high humidity. After 16 hours of treatment in a high humidity environment, the appearance of the paint film is checked for cracks, blistering, and rust to determine the film formation properties of the paint film. Harsh environment recovery: Immediately after spraying, place the coating in a covered water tank, maintain an ambient humidity of ≥90%, remove it after 16 hours, air dry at room temperature, and test the adhesion performance after 24 hours, simulating a high humidity environment; the adhesion is tested according to the cross-cut test of paint and varnish film in GB / T 9286-1998. Salt spray resistance: After air drying (23±2℃) for 7 days, test according to GB / T 1771.

[0056] The performance test results of the waterborne epoxy primers in Examples 1-2 and Comparative Examples 1-3 are shown in Table 1.

[0057] Table 1: Performance test results of waterborne epoxy primers in Examples 1-2 and Comparative Examples 1-3

[0058] As can be seen from Table 1, the waterborne epoxy primer of the present invention has good initial water resistance, early water and rain resistance, harsh environment recovery, salt spray resistance, and flash rust resistance, which can well meet the construction requirements of steel structures in complex and variable outdoor environments.

[0059] Comparative Example 1 uses an epoxy resin with an epoxy equivalent of 900-1300 g / mol, resulting in Comparative Example 1 having inferior initial water resistance, early water and rain resistance, and salt spray resistance compared to Example 1. This demonstrates that only by using the specific waterborne epoxy resin of this invention can the waterborne epoxy primer simultaneously achieve good initial water resistance, early water and rain resistance, resilience in harsh environments, salt spray resistance, and flash rust resistance.

[0060] Comparative Example 2 used only waterborne epoxy resin JT-WBE550, resulting in inferior environmental resilience and salt spray resistance compared to Example 1. This demonstrates that the present invention employs a combination of epoxy resins with an epoxy equivalent of 700-900 g / mol and epoxy resins with an epoxy equivalent of 2800-4200 g / mol to achieve a waterborne epoxy primer that simultaneously provides good initial water resistance, early water and rain resistance, environmental resilience, salt spray resistance, and flash rust resistance. This provides a reliable and efficient waterborne anti-corrosion coating for steel structures, effectively addressing the complex and variable environments encountered during actual outdoor construction of steel structures.

[0061] Comparative Example 3 used a different waterborne epoxy curing agent with an active hydrogen equivalent of 350 g / Eq. This resulted in Comparative Example 3 exhibiting inferior initial water resistance, early water and rain resistance, flash rust resistance, resilience in harsh environments, and salt spray resistance compared to Example 1. This demonstrates that the present invention utilizes a waterborne epoxy curing agent with a specific active hydrogen equivalent to achieve excellent initial water resistance, early water and rain resistance, resilience in harsh environments, salt spray resistance, and flash rust resistance in the waterborne epoxy primer, thus meeting the requirements for steel structure construction in complex and variable outdoor environments.

[0062] In summary, this invention employs a composite of epoxy resins with an epoxy equivalent of 700-900 g / mol and epoxy resins with an epoxy equivalent of 2800-4200 g / mol, combined with a waterborne epoxy curing agent with a specific active hydrogen equivalent. This results in a waterborne epoxy primer that simultaneously possesses excellent early water resistance, long-lasting heavy-duty corrosion protection, and resilience in harsh environments, as well as good resistance to flash rust. It can effectively address the variable environmental conditions that may be encountered during outdoor construction of large structural components such as steel structures. The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A water-based epoxy primer, characterized in that, The waterborne epoxy primer comprises component A and component B; Component A includes waterborne epoxy resin, a first additive, pigments and fillers, and water. Component B includes an aqueous epoxy curing agent, a second auxiliary agent, and water; The waterborne epoxy resin includes epoxy resin with an epoxy equivalent of 700-900 g / mol and epoxy resin with an epoxy equivalent of 2800-4200 g / mol. The active hydrogen equivalent of the waterborne epoxy curing agent is 120-250 g / Eq.

2. The waterborne epoxy primer according to claim 1, characterized in that, By weight, component A comprises 40-60 parts of waterborne epoxy resin, 2.4-10.2 parts of first additive, 17-43 parts of pigments and fillers, and 10-20 parts of water.

3. The waterborne epoxy primer according to claim 1, characterized in that, Component B comprises 1-5 parts of water-based epoxy curing agent, 0.5-6.5 parts of second auxiliary agent, and 2-10 parts of water.

4. The waterborne epoxy primer according to claim 1, characterized in that, The first additive includes at least one of film-forming aids, anti-settling agents, wetting and dispersing agents, defoamers, substrate wetting agents, adhesion promoters, and thickeners; And / or, the pigments and fillers include rust-preventive pigments and fillers; And / or, the second additive includes at least one of a co-solvent and an anti-flash rust agent.

5. The waterborne epoxy primer according to claim 4, characterized in that, By weight, component A comprises 40-60 parts of waterborne epoxy resin, 2-8 parts of rust-preventive pigment, 15-35 parts of filler, 1-4 parts of film-forming aid, 0.1-0.5 parts of anti-settling agent, 0.5-2 parts of wetting and dispersing agent, 0.1-0.5 parts of defoamer, 0.1-0.7 parts of substrate wetting agent, 0.1-0.5 parts of adhesion promoter, 0.5-2.0 parts of thickener, and 10-20 parts of water; And / or, Part B comprises 1-5 parts of water-based epoxy curing agent, 0-5 parts of co-solvent, 0.5-1.5 parts of anti-flash rust agent and 2-10 parts of water.

6. The waterborne epoxy primer according to claim 5, characterized in that, The rust-preventive pigment includes phosphate-based rust-preventive pigments; and / or, the filler includes at least one of titanium dioxide, precipitated barium sulfate, talc, mica powder, silica fume, feldspar powder, wollastonite, and carbon black.

7. The waterborne epoxy primer according to claim 5, characterized in that, The wetting and dispersing agent includes a high molecular weight block graft copolymer; And / or, the defoamer includes at least one of silicone defoamers, mineral oil defoamers, and acetylenic diol defoamers; And / or, the anti-settling agent includes at least one of bentonite and fumed silica; And / or, the film-forming aid includes alcohol ether solvents; And / or, the thickener includes a polyurethane thickener; And / or, the co-solvent includes alcohol ether solvents.

8. The waterborne epoxy primer according to any one of claims 1-7, characterized in that, The mass ratio of component A to component B is (8-20):

1.

9. The method for preparing the waterborne epoxy primer according to any one of claims 1-8, characterized in that, The preparation method includes the following steps: The raw material components of component A are mixed to obtain component A; The raw material components of component B are mixed to obtain component B; The components A and B constitute the waterborne epoxy primer.

10. The application of the waterborne epoxy primer according to any one of claims 1-8 in steel structure engineering.

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