Epoxy zinc-rich primer with high adhesiveness and preparation method thereof

Abstract

The invention discloses a high-performance epoxy zinc-rich primer and a preparation method thereof. The high-performance epoxy zinc-rich primer is composed of a main agent and a curing agent. The main agent comprises waterborne epoxy resin, modified zinc powder, a dispersing agent, an anti-flash-rust agent, organic bentonite, a cosolvent, a base material wetting agent and an adhesion promoter; the curing agent is a water-based polyamide epoxy curing agent aqueous solution; by optimizing the proportion of the components and adopting a special preparation process, the product has excellent adhesive force, salt fog resistance and storage stability; the primer is especially suitable for heavy-duty anticorrosion fields of containers, steel structures, engineering machinery and the like, is simple and convenient to construct and outstanding in environmental protection performance, and solves the technical problems of insufficient adhesive force, poor anticorrosion performance and the like of traditional products.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of anticorrosive coatings, and relates to an epoxy zinc-rich primer with high adhesion and a preparation method thereof, which is particularly suitable for heavy-duty anticorrosion fields such as containers, steel structures and engineering machinery. BACKGROUND

[0002] With increasingly stringent environmental regulations, waterborne coatings have been widely used in the field of industrial corrosion protection. In the heavy-duty anticorrosion field, epoxy zinc-rich primer has become the first choice for long-term corrosion protection of steel structures, containers and the like due to its excellent cathodic protection performance. However, the traditional waterborne epoxy zinc-rich primer still faces many technical challenges in practical application. First, as a key anticorrosive component, the content and dispersibility of zinc powder directly affect the corrosion protection performance of the coating. In the prior art, the content of zinc powder is usually between 60-70%, which is difficult to meet higher corrosion protection requirements. At the same time, the easy sedimentation characteristics of zinc powder result in poor storage stability of the coating, which needs to be stirred frequently before construction, increasing the construction difficulty. Second, the inherent surface tension problem of the waterborne system leads to insufficient adhesion of the coating to the substrate, especially on the surface of the substrate that is wet or not well treated, which is prone to early rusting and peeling of the coating. Although the prior art improves the adhesion by adding various additives, it often comes at the expense of other performance. In addition, the traditional production process usually needs a grinding step to ensure uniform dispersion of zinc powder, which not only increases energy consumption and production cost, but also may lead to oxidation of zinc powder, affecting the final corrosion protection effect. The unique flash rust problem of waterborne coatings has not been well solved in the construction process.

[0003] In terms of application performance, existing products often have difficulty in balancing fast drying and pot life, with a narrow construction window, which brings inconvenience to large-scale industrial application. In particular, in the field of container manufacturing and the like that requires rapid turnover, existing products are difficult to meet the demand for high-efficiency construction.

[0004] CN201711383267 discloses a waterborne epoxy zinc-rich primer for container pretreatment and a preparation method thereof, which is composed of A component and B component with a weight ratio of 1:6; wherein the A component includes modified bisphenol A type epoxy resin emulsion and defoaming agent; the B component includes water-soluble modified amine curing agent, dispersant, film-forming aid, fumed silica, talc, zinc powder, zinc powder protective agent and anti-settling agent; although the waterborne epoxy zinc-rich primer prolongs the pot life and reduces VOC by using modified resin, the fixed ratio of 1:6 of the main agent and the curing agent limits the construction flexibility, and the coarse particle size of zinc powder may lead to insufficient dry film density and corrosion protection performance; in addition, the double anti-settling agents of fumed silica and organic bentonite make the formula complex and the cost high.

[0005] CN202311020185 discloses a nano-titanium modified flaky zinc powder anticorrosive coating and a preparation method thereof. Although the nano-titanium modified flaky zinc powder coating improves corrosion resistance, the solvent type system used contains toluene, xylene and the like, and VOC emission is high, which does not meet the environmental protection trend. Moreover, the preparation process is complex, and ball milling is required for 6-10 hours, which consumes a large amount of energy. The diameter-thickness ratio of the flaky zinc powder is difficult to control, and the uniformity of the coating is poor.

[0006] CN202411359162 discloses a zero-VOC water-based emulsion coating applied to container maintenance and a preparation method thereof. The coating comprises, by weight fraction: 50-60 parts of water-based hybrid emulsion, 1-3 parts of film-forming additive, 0.5-1 part of wet dispersant, 0.2-0.4 part of defoaming agent, 0.5-1 part of adhesion promoter, 0.3-0.5 part of thickening agent, 10-20 parts of pigment, 3-5 parts of anti-rust pigment, 0.5-1 part of corrosion inhibitor, 0.2-0.4 part of base material wetting agent, and 15-26 parts of deionized water. The water-based hybrid emulsion is a water-based single-component acrylic epoxy hybrid emulsion, and the film-forming additive is an alcohol ether compound. The zero-VOC environmental protection advantage of the water-based emulsion coating is significant, but the single-component design sacrifices part of the performance. The 200-300 hour salt spray resistance performance is only applicable to the maintenance scene, and cannot meet the long-term corrosion prevention requirements of newly built containers. Moreover, the cost is high due to the reliance on acrylic epoxy hybrid emulsion, and the 2 hour drying speed is slower than that of solvent type coating.

[0007] In view of the above problems, there is an urgent need in the industry to develop a new type of water-based epoxy zinc-rich primer that can solve the technical bottlenecks of storage stability, adhesion, construction performance and the like while ensuring high zinc content, and meet the increasingly high requirements of industrial corrosion prevention. SUMMARY

[0008] The purpose of the present application is to provide an epoxy zinc-rich primer with high adhesion, which has the characteristics of high dry film zinc content, excellent corrosion resistance, strong adhesion, and simple construction. Through specific formula design and preparation process, the present application solves the technical problems of zinc powder sedimentation, insufficient dry film zinc content, and poor adhesion of existing water-based epoxy zinc-rich primer, optimizes the production process, and realizes a uniform and stable coating system without grinding, significantly improving production efficiency and product performance stability.

[0009] The purpose of the present application can be achieved by the following technical solutions: In a first aspect, the present application provides an epoxy zinc-rich primer with high adhesion, which is composed of a main agent and a curing agent. The main agent comprises the following components by weight percentage: Water-based epoxy resin 10-30%; Modified zinc powder 70-80%; Dispersant 1-3%; Anti-flash rust agent 1-2%; Organic bentonite 1-2%; Co-solvent 1-5%; Substrate wetting agent 0.5-1%; Adhesion promoter 0.5-1%; The modified zinc powder is obtained by modifying flaky zinc powder with polydiallyldimethylammonium chloride and imidazole ionic liquid; The curing agent is composed of water-based polyamide epoxy curing agent 10-20% and water 80-90%.

[0010] The epoxy zinc-rich primer with high adhesion provided by the application adopts an innovative high-zinc powder formula design, the content of zinc powder is controlled between 70-80%, and the ratio with water-based epoxy resin 10-30% forms a synergistic effect, which can build a dense cathodic protection network in the coating, significantly improving the corrosion resistance. The specially selected 5-15 micron particle size zinc powder ensures that the dry film zinc content reaches more than 80%, providing long-term protection for metal substrates; 1-2% of organic bentonite is added in the formula as an anti-settling agent, which does not need to be used with fumed silica, and its unique lamellar structure can form a three-dimensional network in the system, effectively preventing zinc powder from settling; at the same time, 0.5-1% of a special adhesion promoter is added, which greatly improves the adhesion of the coating to the substrate through chemical bonding; the anti-flash rust agent is preferably zinc phosphate or aluminum tripolyphosphate, which can form a passivation film on the metal surface, effectively inhibiting the flash rust phenomenon during construction; the co-solvent system uses environmentally friendly propylene glycol butyl ether or dipropylene glycol butyl ether, which has a moderate evaporation rate, which can ensure the construction performance, and will not affect the film quality.

[0011] Preferably, the particle size of the zinc powder is 5-15 μm, and the dry film zinc content is ≥80%.

[0012] The epoxy zinc-rich primer with high adhesion as described above, the preparation method of the modified zinc powder is as follows: S1, under nitrogen protection, 1.5-2.5 parts of polydiallyldimethylammonium chloride is mixed with deionized water to obtain a solution with a mass fraction of 2-5%, 100 parts of flaky zinc powder is continuously added to the solution, stirred at 200-300 r / min for 15-30 min, and then filtered, the obtained product is washed with deionized water under carbon dioxide gas protection, and then dried in an oven at 60℃ for 24h to obtain a mixture A; S2, take 75 parts of mixture A, 100 parts of ethanol and 4-6 parts of imidazole ionic liquid, stir to dissolve the ionic liquid in ethanol, add the dissolved mixed solution to a reaction kettle, stir, heat to 45℃, and react for 12h, wash the filtered solid with ethanol, and dry at 60℃ for 24h to obtain a modified zinc powder.

[0013] The dry film zinc content of the epoxy zinc-rich primer main agent formula of the present application is ≥80%, which can significantly improve the cathodic protection effect, thereby improving the corrosion resistance of the primer. However, at the same time, such high zinc content also leads to a relative reduction in the water-based epoxy resin therein, which is not sufficient to completely wrap and firmly bond all zinc powder particles, which can easily lead to a decrease in adhesion and mechanical properties; and the high-zinc-content coating has a high solid content, and the viscosity increases rapidly after mixing, making it difficult to apply and cure; due to the high density of zinc powder, it is extremely easy to settle and agglomerate during storage. If the stirring is not sufficient, it can lead to inconsistent zinc content in the paint film at different stages during coating, which seriously affects the final performance.

[0014] Therefore, the present application uses polydiallyldimethylammonium chloride and imidazole ionic liquid to treat zinc powder. First, polydiallyldimethylammonium chloride is used for treatment, which utilizes the strong electrostatic adsorption between the quaternary ammonium salt cation on the polydiallyldimethylammonium chloride chain and the usually negatively charged zinc powder surface (because it always has a layer of zinc oxide ZnO) to form a firm cationic polymer coating film on the surface of the zinc powder particles, which can improve the adhesion of zinc powder in the water-based epoxy resin. Firm adhesion means that the coating is more resistant to mechanical impact, wear and deformation, and is less likely to crack, peel and other physical failures, and enhanced adhesion is the basis for long-term corrosion protection; it can also improve the dispersion stability of zinc powder in the water-based system and prevent settling. And it can serve as an intermediate layer to provide a foundation for further processing.

[0015] Then, a hydrophobic barrier is constructed around the coating layer by the organic long chain in the ionic liquid, which forms a dense molecular barrier that effectively blocks the intrusion of water and electrolytes, avoiding the reaction of zinc powder with water during mixing and storage, thus producing hydrogen (H2) bubbles, porosity and other problems, making the cured paint film more dense and less defective, thereby providing better physical shielding. It greatly slows down the corrosion process. Through synergistic treatment, the compatibility of zinc powder is further improved and corrosion inhibition is provided. The modified layer (especially the ionic liquid) perfectly solves the problem of hydrogen (H2) production caused by the reaction of zinc powder with water during mixing and storage with water-based resin.

[0016] Therefore, the zinc powder prepared by the present application can not only provide excellent corrosion protection, but also improve the reduction of active zinc surface caused by traditional modified zinc powder and slow down the corrosion dissolution rate of zinc. Preferably, the co-solvent is propylene glycol butyl ether and / or dipropylene glycol butyl ether.

[0017] Preferably, the anti-flash rust agent is zinc phosphate and / or aluminum tripolyphosphate.

[0018] Preferably, the use ratio of the main agent to the curing agent is (3.5-5):1.

[0019] Preferably, the imidazole ionic liquid is one or more of 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium acetate.

[0020] The present application provides an epoxy zinc-rich primer with high adhesion, which uses a water-based polyamide epoxy curing agent and water in a ratio of 10-20% to 80-90% to form a low-VOC environmentally friendly system; the ratio of the curing agent to the main agent is designed to be 3.5 to 1 to 5 to 1, and this ratio range, which has been verified by a large number of experiments, can perfectly balance the working life and curing performance; under this ratio, the coating can maintain a working life of more than 4 hours, while ensuring that the coating after complete curing has excellent mechanical properties and corrosion resistance, with an actual adhesion of more than 5 MPa and a salt spray resistance of more than 1000 hours; the water-based polyamide epoxy resin in the curing agent contains active amine groups, which can crosslink with the epoxy groups in the main agent to form a dense three-dimensional network structure. In a second aspect, the present application also provides a preparation method of the epoxy zinc-rich primer as described in the first aspect, comprising the following steps: (1) Main agent preparation: mix water-based epoxy resin, dispersing agent, substrate wetting agent, and cosolvent, and stir at low speed for 10-15 min; (2) Add modified zinc powder, organic bentonite, and anti-flash rust agent, and disperse at a speed of 1000-1500 r / min for 20-30 min until uniform; (3) Curing agent preparation: mix water-based polyamide epoxy curing agent with water and stir until uniform.

[0021] The present application provides a preparation method of an epoxy zinc-rich primer, which uses an innovative two-step dispersion technology: first, mix water-based epoxy resin, dispersing agent, substrate wetting agent, and cosolvent under low-speed stirring for 10-15 min to achieve preliminary mixing; then add modified zinc powder, organic bentonite, and anti-flash rust agent, and increase the stirring speed to 1000-1500 r / min for 20-30 min of high-speed dispersion; this process design completely avoids the grinding step in traditional processes, greatly reducing energy consumption and production costs; the preparation of the curing agent is even simpler, as it only needs to mix water-based polyamide epoxy curing agent with water and stir until uniform; before construction, mix the main agent and the curing agent in the appropriate ratio and age for 10 min; this aging process allows the components to fully emulsify and fuse, ensuring that the final 20-50 μm dry film is uniform and dense without defects such as pinholes.

[0022] Preferably, the main agent preparation process does not require grinding.

[0023] Preferably, it also includes a construction step: mix the main agent and the curing agent and age for 10 min to form a 20-50 μm dry film.

[0024] Preferably, it is suitable for container primer, steel structure corrosion protection or engineering machinery coating.

[0025] The epoxy zinc-rich primer provided by the application is particularly suitable for container primer, steel structure corrosion protection and engineering machinery coating and other heavy anti-corrosion fields; the high zinc content in the formula provides excellent cathodic protection effect for the metal base material, and the optimized fast-drying characteristics can realize the surface drying speed within 30 minutes, fully meeting the efficient needs of modern production lines; the three-dimensional network structure formed by the organic bentonite gives the product excellent storage stability, and the measured sedimentation rate is ≤5% per month, the product takes into account the construction performance and environmental protection requirements, the VOC content is strictly controlled below 200g / L, and the product shows wide adaptability to different construction environments and base material conditions, and can provide durable and reliable corrosion protection for new projects or maintenance.

[0026] The application has the following beneficial effects: (1) The epoxy zinc-rich primer provided by the application has high adhesion, the dry film zinc content is ≥80%, and the polydiallyldimethylammonium chloride and imidazole ionic liquid are used for modification treatment, so that the problem of poor adhesion of traditional high zinc content can be overcome, and the cathodic protection effect and corrosion resistance are significantly improved; (2) The epoxy zinc-rich primer provided by the application has high adhesion, and the adhesion promoter and the base material wetting agent are added in a specific proportion, so that the adhesion between the coating and the base material is significantly improved, and the problem of insufficient adhesion of water-based paint is solved; (3) The preparation method of the epoxy zinc-rich primer provided by the application has high adhesion, and the formula in the design optimization range makes it unnecessary to grind during the preparation of the main agent, simplifies the production process and reduces the production cost. DETAILED DESCRIPTION

[0027] In order to further illustrate the technical means and effects adopted by the application to achieve the predetermined application purposes, the specific embodiments, structures, features and effects according to the application are described in detail as follows. In the following examples and comparative examples, the imidazole ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate, which is purchased from Hubei Jiahui Xingcheng Biological Technology Co., Ltd., and the article number is JHXC-48; the type of the water-based epoxy resin is Banco2092; the polydiallyldimethylammonium chloride is purchased from Wuhan Jiyesheng Chemical Co., Ltd., and the article number is 1436.

[0028] In one embodiment, the present application provides an epoxy zinc-rich primer with high adhesion, which is composed of a main agent and a curing agent, wherein the main agent comprises 10-30% of water-based epoxy resin, 70-80% of modified zinc powder, 1-3% of dispersant, 1-2% of anti-fouling agent, 1-2% of organic bentonite, 1-5% of cosolvent, 0.5-1% of substrate wetting agent, and 0.5-1% of adhesion promoter, the particle size of the zinc powder is 5-15 μm, the cosolvent is selected from propylene glycol butyl ether and / or dipropylene glycol butyl ether, and the anti-fouling agent is selected from zinc phosphate and / or aluminum tripolyphosphate; the curing agent is composed of 10-20% of water-based polyamide epoxy curing agent and 80-90% of water, and the use ratio of the main agent to the curing agent is (3.5-5):1; In another embodiment, the present application provides a preparation method of the epoxy zinc-rich primer, which specifically comprises the following steps: firstly, mixing 10-30% of water-based epoxy resin, 1-3% of dispersant, 0.5-1% of substrate wetting agent, and 1-5% of cosolvent, and stirring at a low speed for 10-15 minutes, then adding 70-80% of modified zinc powder, 1-2% of organic bentonite, and 1-2% of anti-fouling agent, and high-speed dispersing at a rotating speed of 1000-1500 r / min for 20-30 minutes until uniform; meanwhile, mixing 10-20% of water-based polyamide epoxy curing agent with 80-90% of water and stirring until uniform; when used, mixing the main agent with the curing agent at a ratio of (3.5-5):1, aging for 10 minutes, and then applying to form a dry film coating with a thickness of 20-50 μm.

[0029] Example 1 The present embodiment provides an epoxy zinc-rich primer with high adhesion, which is composed of a main agent and a curing agent. The main agent comprises 20% of water-based epoxy resin, 75% of modified zinc powder with a particle size of 10 μm, 2% of dispersant, 1.5% of zinc phosphate as anti-fouling agent, 1.5% of organic bentonite, 3% of dipropylene glycol butyl ether, 0.8% of substrate wetting agent, and 0.7% of adhesion promoter. The curing agent is composed of 15% of water-based polyamide epoxy curing agent and 85% of water, and the use ratio of the main agent to the curing agent is 4:1. Preparation of modified zinc powder: S1, under nitrogen protection, 1.5 parts of polydiallyldimethylammonium chloride was mixed with deionized water to obtain a solution with a mass fraction of 2%, 100 parts of flaky zinc powder was continuously added to the solution, stirred at 200 r / min for 15 min, and then filtered, and the obtained product was washed with deionized water under carbon dioxide gas protection, and then dried in an oven at 60°C for 24 h to obtain a mixture A; S2, take 75 parts of mixture A, 100 parts of ethanol and 4 parts of imidazole ionic liquid, stir to dissolve the ionic liquid in ethanol, add the dissolved mixture solution to the reactor, stir, heat to 45℃ for 12h, wash the filtered solid with ethanol, dry at 60℃ for 24h to obtain modified zinc powder; The preparation method of the epoxy zinc-rich primer provided by the embodiment comprises the following steps: mixing 20% of water-based epoxy resin, 2% of dispersant, 0.8% of substrate wetting agent and 3% of dipropylene glycol butyl ether at a stirring speed of 300 r / min for 12 minutes; adding 75% of modified zinc powder with a particle size of 10 μm, 1.5% of organic bentonite and 1.5% of zinc phosphate, and dispersing at a high speed of 1200 r / min for 25 minutes; meanwhile, mixing and stirring 15% of water-based polyamide epoxy curing agent with 85% of water until uniform; and mixing the two at a ratio of 4:1 for aging for 10 minutes to form a dry film with a thickness of 30 μm.

[0030] Embodiment 2 The embodiment provides an epoxy zinc-rich primer with high adhesion, which is composed of a main agent and a curing agent. The main agent comprises 15% of water-based epoxy resin, 78% of modified zinc powder with a particle size of 8 μm, 1.5% of dispersant, 1% of aluminum tripolyphosphate as a flash rust inhibitor, 1% of organic bentonite, 2% of propylene glycol butyl ether, 0.5% of substrate wetting agent and 1% of adhesion promoter. The curing agent is composed of 12% of water-based polyamide epoxy curing agent and 88% of water, and the use ratio of the main agent to the curing agent is 3.5:1. Preparation of modified zinc powder: S1, under nitrogen protection, 1.5-2.5 parts of polydiallyldimethylammonium chloride are mixed with deionized water to obtain a solution with a mass fraction of 3%, 100 parts of flaky zinc powder are continuously added to the solution, and stirring is performed at 250 r / min for 20 min, then the obtained product is washed with deionized water under carbon dioxide gas protection, and then dried in an oven at 60℃ for 24h to obtain mixture A; S2, take 75 parts of mixture A, 100 parts of ethanol and 4 parts of imidazole ionic liquid, stir to dissolve the ionic liquid in ethanol, add the dissolved mixture solution to the reactor, stir, heat to 45℃ for 12h, wash the filtered solid with ethanol, dry at 60℃ for 24h to obtain modified zinc powder; The embodiment also provides a preparation method of the epoxy zinc-rich primer, comprising the following steps: mixing 15% of the water-based epoxy resin, 1.5% of the dispersant, 0.5% of the substrate wetting agent and 2% of the propylene glycol butyl ether, stirring at a low speed of 300 r / min for 15 min; adding 78% of the modified zinc powder with a particle size of 8 μm, 1% of the organic bentonite and 1% of the aluminum tripolyphosphate, and dispersing at a high speed of 1000 r / min for 30 min; meanwhile, mixing and stirring 12% of the water-based polyamide epoxy curing agent with 88% of water until uniform; and mixing and aging for 10 min at a ratio of 3.5:1 when in use, so as to form a dry film with a thickness of 20 μm.

[0031] Embodiment 3 The embodiment provides an epoxy zinc-rich primer with high adhesion, which is composed of a main agent and a curing agent. The main agent comprises 25% of the water-based epoxy resin, 72% of the modified zinc powder with a particle size of 12 μm, 2.5% of the dispersant, 2% of the zinc phosphate mixed with the aluminum tripolyphosphate at a ratio of 1:1 as a flash rust inhibitor, 2% of the organic bentonite, 4% of the dipropylene glycol butyl ether, 1% of the substrate wetting agent and 0.5% of the adhesion promoter. The curing agent is composed of 18% of the water-based polyamide epoxy curing agent and 82% of water, and the use ratio of the main agent to the curing agent is 5:1.

[0032] Preparation of the modified zinc powder: S1, under the protection of nitrogen, 2.5 parts of polydiallyldimethylammonium chloride are mixed with deionized water to obtain a solution with a mass fraction of 5%, 100 parts of flaky zinc powder are continuously added to the solution, stirring is performed at 300 r / min for 30 min, the obtained product is washed with deionized water under the protection of carbon dioxide gas, and then drying is performed at 60 ℃ in an oven for 24 h to obtain a mixture A; S2, 75 parts of the mixture A, 100 parts of ethanol and 6 parts of an imidazole ionic liquid are taken, the ionic liquid is fully dissolved in the ethanol by stirring, the mixed solution after dissolution is added to a reaction kettle, stirring is performed, the temperature is raised to 45 ℃, and reaction is performed for 12 h, the filtered solid is washed with ethanol, and drying is performed at 60 ℃ for 24 h to obtain the modified zinc powder; The embodiment also provides a preparation method of the epoxy zinc-rich primer, comprising the following steps: mixing 25% of the water-based epoxy resin, 2.5% of the dispersant, 1% of the substrate wetting agent and 4% of the dipropylene glycol butyl ether, stirring at a low speed of 300 r / min for 10 min; adding 72% of the modified zinc powder with a particle size of 12 μm, 2% of the organic bentonite and 2% of the mixed flash rust inhibitor, and dispersing at a high speed of 1500 r / min for 20 min; meanwhile, mixing and stirring 18% of the water-based polyamide epoxy curing agent with 82% of water until uniform; and mixing and aging for 10 min at a ratio of 5:1 when in use, so as to form a dry film with a thickness of 40 μm.

[0033] Embodiment 4 The difference between this example and example 1 is only that the organic bentonite is increased to 2%, while the modified zinc powder is reduced to 73%, and the resin content is kept at 20%, and the rest of the parameters are exactly the same as in example 1.

[0034] Example 5 The difference between this example and example 1 is only that the flaky zinc powder (aspect ratio > 30) is used instead of spherical zinc powder, and the organic bentonite is reduced to 1%, and the rest of the parameters are exactly the same as in example 1.

[0035] Example 6 The difference between this example and example 1 is only that 3% DPNB + 2% ethylene glycol butyl ether mixed co-solvent is used, and the curing agent is adjusted to 18%, and the rest of the parameters are exactly the same as in example 1.

[0036] Example 7 The difference between this example and example 1 is only that 5% DPNB co-solvent is used alone, and the curing agent is adjusted to 12%, and the rest of the parameters are exactly the same as in example 1.

[0037] Example 8 The difference between this example 6 and example 1 is only that 1% zinc phosphate + 0.5% zinc molybdate composite anti-flash rust agent is used, and the silane coupling agent is increased to 1%, and the rest of the parameters are exactly the same as in example 1.

[0038] Example 9 The difference between this example 7 and example 1 is only that 2% aluminum tripolyphosphate anti-flash rust agent is used, and 0.5% titanate coupling agent (NDZ-201) is used, and the rest of the parameters are exactly the same as in example 1.

[0039] Comparative Example 1 The difference between this comparative example and example 1 is only that 3% zinc phosphate + 2% sodium nitrite composite anti-flash rust system is used, and the rest of the parameters are exactly the same as in example 1.

[0040] Comparative Example 2 The difference between this comparative example and example 1 is only that 5% organic bentonite + 0.3% substrate wetting agent is used, and the rest of the parameters are exactly the same as in example 1.

[0041] Comparative Example 3 The difference between this comparative example and example 1 is only that the high-speed dispersion rotation speed is reduced to 600 rpm, and the rest of the parameters are exactly the same as in example 1.

[0042] Comparative Example 4 The difference between this comparative example and example 1 is only that the maturation time is extended to 30 min, and the rest of the parameters are exactly the same as in example 1.

[0043] Comparative Example 5 The difference between the present comparative example and Example 1 is only that the ratio of the main agent to the curing agent is adjusted to 2:1, and the rest of the parameters are exactly the same as those of Example 1.

[0044] Comparative Example 6 The difference between the present comparative example and Example 1 is only that the ratio of the main agent to the curing agent is adjusted to 7:1, and the rest of the parameters are exactly the same as those of Example 1.

[0045] Comparative Example 7 The difference between the present comparative example and Example 1 is only that polydiallyldimethylammonium chloride is not added in the preparation process of the modified zinc powder, and the rest of the parameters are exactly the same as those of Example 1.

[0046] Comparative Example 8 The difference between the present comparative example and Example 1 is only that the ionic liquid is not added in the preparation process of the modified zinc powder, and the rest of the parameters are exactly the same as those of Example 1.

[0047] Comparative Example 9 The difference between the present comparative example and Example 1 is only that the zinc powder is not modified, and the rest of the parameters are exactly the same as those of Example 1.

[0048] The high-adhesion epoxy zinc-rich primer of Examples 1-9 and Comparative Examples 1-6 is subjected to performance testing, all tests are performed according to GB / T 5210 (adhesion), GB / T 1771 (salt spray) standards, and the test substrate is sandblasted steel plate (Sa2.5), and the test results are shown in Table 1.

[0049] Table 1 Adhesion (MPa) Salt fog resistance (h) Drying time (min) Pot life (h) Settling stability (30 d) Example 1 6.5 1000 30 4 ≤5% Example 2 6.8 950 35 4.5 ≤5% Example 3 7.0 1100 25 3.5 ≤8% Example 4 6.2 1050 32 4 ≤3% Example 5 7.2 1200 28 4 ≤6% Example 6 6.3 980 40 5 ≤5% Example 7 5.8 900 45 3 ≤7% Example 8 7.5 1300 35 4 ≤4% Example 9 7.0 1150 30 4.5 ≤5% Comparative Example 1 4.2 600 25 2 ≤15% Comparative Example 2 5.0 800 50 3 Layering Comparative Example 3 3.8 500 30 4 ≤20% Comparative Example 4 5.5 850 30 1.5 ≤5% Comparative Example 5 4.0 700 60 6 ≤5% Comparative Example 6 3.5 400 20 2 ≤5% Through comparative analysis of the above test data, we can draw the following conclusions: (1) The epoxy zinc-rich primer provided by the present application realizes excellent comprehensive performance by precisely controlling the component ratio and process parameters. Specifically, Examples 1-9 are significantly superior to Comparative Examples 1-6 in key performance indicators such as adhesion, salt spray resistance, drying time, and storage stability. Among them, Example 1 as the benchmark formula, exhibits an adhesion of 6.5 MPa, a salt spray resistance of 1000 h, a drying time of 30 min, and good storage stability, which is due to its reasonable formula design: a balanced ratio of 20% water-based epoxy resin to 75% zinc powder, a synergistic system formed by 1.5% organic bentonite and 0.7% silane coupling agent, and a high-speed dispersion process of 1200 r / min; (2) In the zinc powder system optimization, comparative example 1 and examples 4-5 can find that: example 4 increases the content of organic bentonite to 2% and adjusts the content of zinc powder to 73% accordingly, although the sedimentation stability is increased to less than 3% for 30 days, the adhesion is slightly decreased to 6.2 MPa, which shows that the content of organic bentonite needs to be controlled in an appropriate range; example 5 uses flaky zinc powder and reduces the dosage of organic bentonite, not only maintains the high adhesion of 7.2 MPa, but also improves the salt spray resistance to 1200h, which proves that the barrier effect of flaky zinc powder can significantly enhance the corrosion resistance; (3) In the co-solvent system, the experimental results of comparative example 1 and examples 6-7 show that: example 6 uses a mixed co-solvent system of 3% DPNB and 2% ethylene glycol butyl ether, and adjusts the content of curing agent to 18%, although the pot life is extended to 5h, the drying time is increased to 40min; example 7 uses 5% DPNB co-solvent alone and reduces the content of curing agent to 12%, which leads to a decrease in adhesion to 5.8 MPa and a decrease in salt spray resistance to 900h, which fully shows that the selection of co-solvent needs to be accurately matched with the curing system; (4) In the anti-flash rust system optimization, the results of comparative example 1 and examples 8-9 show that: example 8 uses a composite anti-flash rust system of 1% zinc phosphate and 0.5% molybdate, combined with 1% silane coupling agent, which realizes the ultra-high adhesion of 7.5 MPa and the excellent salt spray resistance of 1300h; example 9 uses a combination of 2% aluminum tripolyphosphate and 0.5% titanate coupling agent, although the performance is better than the benchmark formula, but the improvement is not as good as example 8, which shows that the synergistic effect of zinc molybdate and silane coupling agent is better; (5) Through the failure mode analysis of comparative examples 1-6, it can be determined that: comparative example 1 uses a strong oxidizing anti-flash rust system of 3% zinc phosphate and 2% sodium nitrite, although the anti-flash rust effect is acceptable, but the adhesion is suddenly decreased to 4.2 MPa; comparative example 2 uses an over-thickening system of 5% organic bentonite and 0.3% substrate wetting agent, which causes storage stratification; comparative example 3 reduces the dispersion rotation speed to 600r / min, which leads to a decrease in adhesion to 3.8 MPa; comparative example 4 extends the curing time to 30min, which shortens the pot life to 1.5h; the ratio imbalance of comparative examples 5-6 respectively leads to curing deficiency and excessive crosslinking. These comparative examples prove the scientificity of the parameter range of the present application from the negative side; (6) According to the performance data in Table 1, Example 8 exhibits the best comprehensive performance balance. The formulation adopts a base ratio of 22% waterborne epoxy resin and 72% flaky zinc powder, combined with 1.2% organic bentonite, a composite anti-flash rust system of 1% zinc phosphate + 0.5% zinc molybdate, 3% mixed cosolvent, 1% silane coupling agent, and 16% curing agent, and a dispersion process of 1400 r / min, achieving an adhesion of 7.5 MPa, a salt spray resistance of 1300 h, a drying time of 35 min, and a pot life of 4 h at a ratio of 4.5:1, which is the best embodiment of the technical solution. This preferred scheme fully embodies the synergistic effect of each component and the optimized combination of process parameters.

[0050] The high-adhesion epoxy zinc-rich primer of Example 1 and Comparative Examples 7-9 was tested for performance, and all tests were performed according to GB / T5210 (adhesion), GB / T 1771 (salt spray) standards, with the test substrate being sandblasted steel plate (Sa2.5), and the test results are shown in Table 2.

[0051] Table 2 Adhesion (MPa) Salt fog resistance (h) Example 1 6.5 1000 Comparative Example 7 4.2 735 Comparative Example 8 4.7 760 Comparative Example 9 3.1 360 According to the data in Table 2, the zinc powder prepared by the present application can effectively help improve the adhesion and corrosion resistance of the paint.

[0052] The epoxy zinc-rich primer provided by the present application significantly improves the adhesion and corrosion resistance of the coating through innovative formulation design and optimized preparation process. The use of a specific ratio of waterborne epoxy resin and zinc powder system, combined with a carefully selected combination of additives and precise process control, enables the product to have excellent storage stability and application performance. The technical solution achieves a perfect balance between corrosion resistance and mechanical properties through the synergistic effect of each component, providing a high-performance environmentally friendly solution for the industrial corrosion prevention field.

[0053] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with a preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of the present application. Any simple modification, equivalent change and modification of the above embodiments made in accordance with the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. An epoxy zinc-rich primer having high adhesion, characterized by comprising: Consists of a main agent and a curing agent, the main agent includes the following components by weight percentage: Waterborne epoxy resin 10-30%; Modified zinc powder 70-80%; Dispersant 1-3%; Anti-flash rust agent 1-2%; Organic bentonite 1-2%; Co-solvent 1-5%; Substrate wetting agent 0.5-1%; Adhesion promoter 0.5-1%; The modified zinc powder is obtained by modifying zinc powder with polydiallyldimethylammonium chloride and imidazole ionic liquid; The curing agent consists of waterborne polyamide epoxy curing agent 10-20% and water 80-90%.

2. The epoxy zinc-rich primer according to claim 1, characterized in that, The particle size of the zinc powder is 5-15 μm, and the dry film zinc content is ≥80%; the preparation method of the modified zinc powder is as follows: S1, under nitrogen protection, 1.5-2.5 parts of polydiallyldimethylammonium chloride is mixed with deionized water to obtain a solution with a mass fraction of 2-5%, 100 parts of flaky zinc powder is continuously added to the solution, stirred at 200-300 r / min for 15-30 min, filtered, and then the obtained product is washed with deionized water under carbon dioxide gas protection, and then dried in an oven at 60℃ for 24h to obtain a mixture A; S2, take 75 parts of mixture A, 100 parts of ethanol and 4-6 parts of imidazole ionic liquid, stir to dissolve the ionic liquid in ethanol, add the dissolved mixed solution to the reaction kettle, stir, heat to 45℃ and react for 12h, wash the filtered solid with ethanol, and dry at 60℃ for 24h to obtain modified zinc powder.

3. The epoxy zinc-rich primer of claim 1, wherein, The co-solvent is propylene glycol butyl ether and / or dipropylene glycol butyl ether.

4. The epoxy zinc-rich primer of claim 1, wherein, The anti-flash rust agent is zinc phosphate and / or aluminum tripolyphosphate.

5. The epoxy zinc-rich primer of claim 1, wherein, The use ratio of the main agent to the curing agent is (3.5-5):

1.

6. The epoxy zinc-rich primer of claim 2, wherein, The imidazole ionic liquid is one or more of 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-butyl-3-methylimidazolium acetate.

7. A process for the preparation of the epoxy zinc-rich primer according to any one of claims 1 to 6, characterized in that, Comprises the following steps: (1) Main agent preparation: mix waterborne epoxy resin, dispersant, substrate wetting agent, and co-solvent, and stir at low speed for 10-15 min; (2) Add modified zinc powder, organic bentonite, and anti-flash rust agent, and disperse at a speed of 1000-1500 r / min for 20-30 min until uniform; (3) Curing agent preparation: mix waterborne polyamide epoxy curing agent with water, and stir until uniform.

8. The production method according to claim 7, characterized by, The main agent preparation process does not require grinding.

9. The preparation method according to claim 7, characterized in that, Also includes a construction step: mix the main agent with the curing agent, mature for 10 min, and form a dry film of 20-50 μm.

10. The epoxy zinc-rich primer according to any one of claims 1 to 6, characterized in that, Suitable for container primer, steel structure corrosion prevention, or engineering machinery coating.