Water-based paint for wind power tower tube steel as well as preparation method and application of water-based paint

Abstract

The invention provides a water-based coating for wind power tower tube steel and a preparation method and application thereof.The water-based coating for the wind power tower tube steel comprises, by weight, a component A: 5-15 parts of modified acrylic emulsion, 30-60 parts of epoxy emulsion, 10-30 parts of hydrophobic group modified organic amine polymer, 1-10 parts of adhesion promoter and 1-30 parts of flaky filler; 1-30 parts of a salt spray resistant filler; and a component B: 5-30 parts of a hydrophobic group modified isocyanate prepolymer. The modified acrylic emulsion, the epoxy emulsion, the hydrophobic group-modified isocyanate prepolymer and the hydrophobic group-modified organic amine polymer are subjected to multiple crosslinking to form a network interpenetrating structure, so that the adhesive force and corrosion resistance of the water-based coating for the wind power tower tube steel are remarkably improved, and meanwhile, the problem that in the construction process of the coating, the water-based coating is not prone to cracking is solved. The ultrahigh film thickness cannot be sprayed at one time; and the drying speed is low.

Description

Technical Field

[0001] The present invention relates to the field of coating technology, and in particular to a water-based coating for wind power tower steel, a preparation method thereof, and applications thereof. Background Art

[0002] Steel is an ideal material for wind turbine towers due to its high strength, stability, and toughness, as well as its suitability for mass production. However, long-term exposure to the environment can lead to corrosion, which reduces its strength and seriously impacts safety. Therefore, in addition to improving the steel itself and using weather-resistant steel plates, it is also necessary to strengthen the corrosion resistance of steel structures.

[0003] Conventional carbon-based water-based coatings for steel use ordinary acrylic emulsions and epoxy emulsions, relying on physical adsorption to bond with the substrate. However, these problems exist: the steel surface is highly inert, resulting in poor bonding with the coating, and the coating easily falls off after high and low temperature cycles; the film-forming substance has a low cross-linking density, poor water resistance and corrosion resistance; the coating contains a high content of organic solvents, resulting in poor environmental performance; the coating dries slowly, resulting in low production efficiency and inability to meet the continuous operation requirements of large workpieces.

[0004] CN111909573A discloses a graphene-modified highly chlorinated polyethylene resin anticorrosive coating, comprising the following components: low-viscosity highly chlorinated polyethylene resin, C9 petroleum resin, xylene, graphene dispersion, chlorinated paraffin, red iron oxide, zinc phosphate, aluminum tripolyphosphate, talc, mica powder, epoxy resin, and additives. The coating significantly improves its anticorrosive effect through the design and compounding of the components, but its drying time is long and its corrosion resistance needs to be improved.

[0005] CN111500148A discloses a graphene-modified, functional, heavy-duty anti-corrosion water-based coating for steel. The coating consists of an epoxy resin composite primer, a fluorocarbon composite topcoat, and a fluorocarbon metal varnish. The epoxy resin composite primer is composed of a water-based epoxy resin, graphene, a dispersant, a diluent, and an epoxy curing agent. However, the coating dries slowly, and its salt spray resistance is only tested for 1000 hours, with no bubbles, rust, or shedding of the functional coating. This leaves room for improvement.

[0006] CN101955718A discloses a high-penetration epoxy resin primer comprising the following components: epoxy resin, a reactive diluent, a transition metal oxide, a curing accelerator, and a curing agent. However, the primer contains as much as 194 g / L of volatile organic compounds, has a long drying time, is environmentally unfriendly, and significantly impacts production efficiency.

[0007] Therefore, developing a water-based coating for wind turbine tower steel with high corrosion resistance and high adhesion is a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0008] In response to the deficiencies in the prior art, the present invention provides a water-based coating for wind turbine tower steel, a preparation method thereof, and an application thereof. Through the design and compounding of the components, the water-based coating for wind turbine tower steel has high adhesion to the substrate, and after high and low temperature cycles, it still maintains strong adhesion. The water-based coating for wind turbine tower steel has excellent corrosion resistance and a fast drying speed. At the same time, it solves the problem that the coating cannot be sprayed with an ultra-high film thickness in one go and has a slow drying speed during the construction process, and can fully meet the performance requirements of harsh environments.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a water-based coating for wind turbine tower steel, wherein the water-based coating for wind turbine tower steel comprises the following components in parts by weight:

[0011] Component A:

[0012]

[0013]

[0014] Component B:

[0015] 5-30 parts of hydrophobic group-modified isocyanate prepolymer.

[0016] The modified acrylic emulsion includes a hydroxyl-modified acrylic emulsion and optionally other modified acrylic emulsions; the other modified acrylic emulsions include a carboxyl-modified acrylic emulsion and / or a silicone-modified acrylic emulsion.

[0017] The modified acrylic emulsion, epoxy emulsion, hydrophobic group-modified isocyanate prepolymer and hydrophobic group-modified organic amine polymer of the present invention undergo multiple cross-linking to form a network interpenetrating structure, which significantly improves the adhesion and corrosion resistance of water-based coatings for wind turbine tower steel and is environmentally friendly.

[0018] The present invention adopts modified acrylic emulsion, wherein the hydroxyl-modified acrylic emulsion contains a large number of hydroxyl groups, which can react with isocyanate groups and epoxy groups to form a covalent cross-linking network, thereby improving the adhesion and mechanical strength of the water-based coating for wind power tower steel; the carboxyl-modified acrylic emulsion contains a large number of carboxyl groups, which adjusts the polarity of the emulsion and promotes electrostatic adsorption between the water-based coating and the steel, and can also chemically react with the adhesion promoter to promote cross-linking; the siloxane-modified acrylic emulsion contains silicon-oxygen bonds and can react with the hydroxyl groups on the surface of the steel, thereby further improving the adhesion between the coating and the substrate.

[0019] The present invention uses a hydrophobic group-modified isocyanate prepolymer. The hydrophobic groups in the isocyanate prepolymer synergize with modified acrylic and epoxy emulsions to significantly improve the coating's wettability on steel substrates. Furthermore, the hydrophobic groups reduce the coating's affinity for water, forming a physical barrier with salt-spray-resistant fillers and flaky fillers, slowing the penetration of corrosive media and enhancing the coating's corrosion resistance.

[0020] The present invention utilizes organic amine polymers modified with hydrophobic groups, which react rapidly with isocyanate groups and active groups in acrylic emulsions, achieving rapid crosslinking and curing at room temperature. This effectively addresses the slow drying speed and low production efficiency of large steel-based workpieces without baking. The dense crosslinked network formed after curing enhances the coating's thixotropy, addressing the difficulty of achieving ultra-high film thicknesses in a single spray application and the associated sag issues during large-scale construction. Furthermore, the coating's water-based design avoids the extensive use of organic solvents, helping to reduce VOC emissions and meeting environmental standards.

[0021] The flaky filler in the present invention can form a "maze-like" shielding effect in the coating, construct a physical shielding layer, effectively hinder the penetration and diffusion of corrosive media, improve the physical barrier performance of the coating, and thereby enhance the corrosion resistance of the coating; the salt spray resistant filler can form a passivation film on the surface of steel. The two realize a dual anti-corrosion mechanism and jointly improve the corrosion resistance of the coating.

[0022] Through the design and mutual compounding of various components, the present invention enables the water-based coating for wind turbine tower steel to form a multi-crosslinked network interpenetrating structure and multiple anti-corrosion mechanisms, which significantly improves the adhesion and corrosion resistance of the water-based coating for wind turbine tower steel. At the same time, it has the characteristics of environmental protection and fast drying speed, and can fully meet the performance requirements of steel in harsh environments.

[0023] In the water-based coating for wind turbine tower steel provided by the present invention, the weight portion of the modified acrylic emulsion is 5-15 parts, for example, 5 parts, 7 parts, 9 parts, 11 parts, 13 parts or 15 parts.

[0024] The weight portion of the epoxy emulsion is 30-60 parts, for example, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, or 60 parts.

[0025] The weight portion of the hydrophobic group-modified organic amine polymer is 10-30 parts, for example, 10 parts, 15 parts, 20 parts, 25 parts or 30 parts.

[0026] The weight portion of the adhesion promoter is 1-10 parts, for example, 1 part, 2 parts, 4 parts, 6 parts, 8 parts or 10 parts.

[0027] The weight portion of the flaky filler is 1-30 parts, for example, 1 part, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts or 30 parts.

[0028] The weight portion of the salt spray resistant filler is 1-30 parts, for example, it can be 1 part, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts or 30 parts.

[0029] The weight portion of the hydrophobic group-modified isocyanate prepolymer is 5-30 parts, for example, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts or 30 parts.

[0030] In the present invention, if the amount of the hydrophobic group-modified isocyanate prepolymer is too small, on the one hand, its synergistic effect with the modified acrylic emulsion and epoxy emulsion is weakened, making it difficult to fully improve the wettability of the coating to the steel substrate, resulting in insufficient coating adhesion and easy peeling. On the other hand, it is impossible to form a sufficiently dense cross-linked network, the shielding effect of the salt spray resistant filler and the flaky filler is difficult to exert, the corrosion resistance of the coating is reduced, and the drying speed is slowed down, and the production efficiency cannot be improved. If the amount is too much, the excessive hydrophobic groups will destroy the stability of the coating system, resulting in poor compatibility of the coating with additives such as substrate wetting agents and dispersants, resulting in stratification and flocculation problems, affecting the construction performance. At the same time, excessive isocyanate groups will make the cross-linking reaction too intense, the viscosity of the coating will increase rapidly, the leveling will deteriorate, and it will easily produce orange peel and pinhole defects, and the sagging phenomenon will be aggravated when applied over a large area. In addition, excessive prepolymers may also increase the cost of the coating, and the flexibility of the over-crosslinked coating will be reduced and it will be easy to crack. At the same time, it may lead to increased VOC emissions, making it difficult to meet environmental protection requirements.

[0031] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0032] Preferably, the epoxy equivalent weight of the epoxy emulsion is 150-500 g / eq, for example, 150 g / eq, 200 g / eq, 250 g / eq, 300 g / eq, 350 g / eq, 400 g / eq, 450 g / eq or 500 g / eq.

[0033] Preferably, the mass percentage of NCO groups in the hydrophobic group-modified isocyanate prepolymer is 5-15%, for example, 5%, 7%, 9%, 11%, 13% or 15%.

[0034] Preferably, the mass percentage of the hydrophobic group in the hydrophobic group-modified isocyanate prepolymer is 0.5-5%, for example, 0.5%, 1%, 2%, 3%, 4% or 5%.

[0035] In the present invention, the content of the hydrophobic group in the hydrophobic group-modified isocyanate prepolymer is 0.5-5%, which ensures that the isocyanate prepolymer is stably dispersed in water, avoids demulsification, and balances water solubility and cross-linking efficiency.

[0036] Preferably, the hydrophobic group in the hydrophobic group-modified isocyanate prepolymer includes any one of dodecyl, polyoxypropylene or polysiloxane.

[0037] Preferably, the mass percentage of amino groups in the hydrophobic group-modified organic amine polymer is 0.5-10%, for example, 0.5%, 1%, 2%, 4%, 6%, 8% or 10%.

[0038] Preferably, the mass percentage of the hydrophobic group in the hydrophobic group-modified organic amine polymer is 0.5-10%, for example, 0.5%, 1%, 2%, 4%, 6%, 8% or 10%.

[0039] Preferably, the hydrophobic group in the hydrophobic group-modified organic amine polymer includes any one of dodecyl, perfluorooctyl or cyclohexyl.

[0040] Preferably, the adhesion promoter includes any one of a functional silane coupling agent, a titanate coupling agent or an acrylic acid phosphate ester, or a combination of at least two thereof.

[0041] Preferably, the functional silane coupling agent includes any one of an amino-modified silane coupling agent, an epoxy-modified silane coupling agent, a mercapto-modified silane coupling agent or a siloxane-grafted silane coupling agent, or a combination of at least two thereof.

[0042] The present invention uses a functional silane coupling agent containing amino, epoxy, mercapto or siloxane grafted chain segments, which can form stronger chemical bonds with functional groups on the surface of steel, such as Si-OC or Si-O-Me. At the same time, the functional silane coupling agent undergoes a cross-linking reaction with a modified acrylic emulsion or epoxy emulsion to form a chemical bridge between the substrate, the functional silane coupling agent and the resin, greatly improving the adhesion and solving the problem of coating shedding after high and low temperature cycles.

[0043] Preferably, the flaky filler includes any one of graphene, mica or glass flakes, or a combination of at least two of them.

[0044] Preferably, the flake filler has a diameter of 1-200 μm.

[0045] Preferably, the flake diameter of graphene is 1-10 μm (for example, 1 μm, 2 μm, 4 μm, 6 μm, 8 μm or 10 μm, etc.), and the flake diameters of mica and glass flakes are each independently 20-200 μm (for example, 20 μm, 50 μm, 100 μm, 150 μm or 200 μm, etc.).

[0046] Preferably, the salt spray resistant filler includes aluminum tripolyphosphate and optionally other salt spray resistant fillers.

[0047] Preferably, the other salt spray resistant fillers include any one of tripolyphosphates, aluminum zinc phosphomolybdates or zinc powder, or a combination of at least two of them.

[0048] Preferably, the water-based coating for wind turbine tower steel further comprises any one of a reinforcing agent, a wetting agent, a rheological additive, a defoaming agent or a dispersant, or a combination of at least two thereof.

[0049] Preferably, the amount of reinforcing agent, wetting agent, rheological additive, defoaming agent or dispersant in the water-based coating for wind turbine tower steel is independently 1-10 parts, for example, 1 part, 2 parts, 4 parts, 6 parts, 8 parts or 10 parts.

[0050] Preferably, the reinforcing agent includes any one of titanium dioxide, silicon dioxide or aluminum oxide, or a combination of at least two of them.

[0051] Preferably, the wetting agent comprises sodium lauryl sulfate and / or polyether-modified polysiloxane.

[0052] Preferably, the rheological additive includes any one of polyurea, bentonite or silica, or a combination of at least two of them.

[0053] Preferably, the defoaming agent includes any one of an organosilicon defoaming agent, a polyether defoaming agent or a mineral oil defoaming agent, or a combination of at least two of them.

[0054] Preferably, the dispersant includes any one of a modified phosphate dispersant, a maleic anhydride modified dispersant or a functional block copolymer dispersant, or a combination of at least two of the above.

[0055] Preferably, the dispersant includes any one of isooctyl polyoxyethylene ether phosphate, maleic anhydride-acrylate copolymer, or polyester-polyethylene glycol block copolymer, or a combination of at least two thereof.

[0056] Preferably, the water-based paint for wind turbine tower steel further includes 50-100 parts of color paste, for example, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts or 100 parts.

[0057] In a second aspect, the present invention provides a method for preparing a water-based coating for a wind turbine tower steel material as described in the first aspect, the preparation method comprising the following steps:

[0058] The modified acrylic emulsion, epoxy emulsion, hydrophobic group-modified organic amine polymer, adhesion promoter, flaky filler and salt spray resistant filler are uniformly mixed to obtain component A;

[0059] Component A and component B are mixed evenly to obtain the water-based coating for wind turbine tower steel.

[0060] Preferably, the materials mixed in the component A further include any one of a reinforcing agent, a wetting agent, a rheological additive, a defoaming agent, a dispersant or a color paste, or a combination of at least two thereof.

[0061] Preferably, the preparation method of the water-based coating for wind turbine tower steel comprises: first mixing a modified acrylic emulsion, an epoxy emulsion, and a hydrophobic group-modified organic amine polymer, adding an adhesion promoter, a flaky filler, a salt spray-resistant filler, a reinforcing agent, and a dispersant thereto, performing a second mixing, then adding a wetting agent, a rheological additive, and a defoaming agent, performing a third mixing, and then adding a color paste and mixing uniformly, and standing to obtain component A;

[0062] Component A and component B are mixed evenly to obtain the water-based coating for wind turbine tower steel.

[0063] Preferably, the mixing equipment is a high-speed disperser.

[0064] Preferably, the rotation speed of the first mixing is 800-1200 r / min, for example, it can be 800 r / min, 900 r / min, 1000 r / min, 1100 r / min or 1200 r / min.

[0065] Preferably, the first mixing time is 20-60 min, for example, 20 min, 30 min, 40 min, 50 min or 60 min.

[0066] Preferably, the second mixing speed is 1000-2000 r / min, for example, 1000 r / min, 1200 r / min, 1400 r / min, 1600 r / min, 1800 r / min or 2000 r / min.

[0067] Preferably, the second mixing time is 30-90 min, for example, 30 min, 45 min, 60 min, 75 min or 90 min.

[0068] Preferably, the rotation speed of the third mixing is 800-1500 r / min, for example, 800 r / min, 1000 r / min, 1200 r / min or 1500 r / min.

[0069] Preferably, the third mixing time is 5-30 min, for example, 5 min, 10 min, 15 min, 20 min, 25 min or 30 min.

[0070] Preferably, the standing time is 10-30 min, for example, 10 min, 15 min, 20 min, 25 min or 30 min.

[0071] Preferably, the method for preparing the water-based coating for wind turbine tower steel specifically comprises the following steps:

[0072] A modified acrylic emulsion, an epoxy emulsion, and an organic amine polymer modified with a hydrophobic group are mixed in a high-speed disperser at 800-1200 r / min for 20-60 min, an adhesion promoter, a flaky filler, a salt spray resistant filler, a reinforcing agent, and a dispersant are added thereto, and the mixture is mixed at 1000-2000 r / min for 30-90 min, and then a wetting agent, a rheological additive, and a defoaming agent are added, and the mixture is mixed at 800-1500 r / min for 5-30 min, and then a color paste is added and mixed uniformly, and the mixture is allowed to stand for 10-30 min to obtain component A;

[0073] Component A and component B are mixed evenly to obtain the water-based coating for wind turbine tower steel.

[0074] In a third aspect, the present invention provides a method for applying the water-based coating to the wind turbine tower steel material according to the first aspect, the method comprising the following steps:

[0075] The wind turbine tower steel is coated with water-based paint on the steel surface and cured.

[0076] Preferably, the steel material is pretreated before coating.

[0077] Preferably, the pretreatment includes the steps of cleaning, sandblasting and surface activation.

[0078] Preferably, the cleaning comprises: scrubbing the steel surface of the wind turbine tower with acetone solvent, blowing it clean with compressed air, and grinding the weld burrs to smoothness with an angle grinder or a wire brush.

[0079] Preferably, the sandblasting includes: using a small desktop sandblasting machine, sandblasting the steel surface at a pressure of 0.6-0.8 MPa (for example, it can be 0.6 MPa, 0.7 MPa or 0.8 MPa, etc.), an angle of 70°-80° between the spray gun and the surface (for example, it can be 70°, 75° or 80°, etc.), and a distance of 200-300 mm between the spray gun and the surface (for example, it can be 200 mm, 250 mm or 300 mm, etc.), and the requirement is to reach Sa2.5 level, that is, the surface is grayish white, free of visible oil, rust, oxide scale and other impurities.

[0080] Preferably, the surface activation comprises: treating the sandblasted steel surface with a zinc phosphate conversion solution.

[0081] Preferably, the concentration of the zinc phosphate conversion solution is 3-5%, for example, 3%, 4% or 5%.

[0082] Preferably, the pH value of the zinc phosphate conversion solution is 4.5-5.5, for example, it can be 4.5, 5.0 or 5.5.

[0083] Preferably, the coating is performed by high-pressure airless spraying.

[0084] Preferably, the pressure of the high-pressure airless spraying is 14-22 MPa, for example, 14 MPa, 16 MPa, 18 MPa, 20 MPa or 22 MPa.

[0085] Preferably, the nozzle diameter of the high-pressure airless spraying is 0.8-2.5 mm, for example, it can be 0.8 mm, 1.0 mm, 1.4 mm, 1.6 mm, 2.0 mm or 2.5 mm.

[0086] Preferably, the coating has a thickness of 150-220 μm, for example, 150 μm, 160 μm, 180 μm, 200 μm or 220 μm.

[0087] Preferably, the curing temperature is 60-100°C, for example, 60°C, 70°C, 80°C, 90°C or 100°C.

[0088] Preferably, the curing time is 20-60 min, for example, 20 min, 30 min, 40 min, 50 min or 60 min.

[0089] Compared with the prior art, the present invention has the following beneficial effects:

[0090] The water-based coating for wind turbine tower steel provided by the present invention forms a network interpenetrating structure through multiple cross-linking between modified acrylic emulsion, epoxy emulsion, hydrophobic group-modified isocyanate prepolymer and hydrophobic group-modified organic amine polymer. The flaky filler and the salt spray-resistant filler form a dual anti-corrosion mechanism, which significantly improves the adhesion and corrosion resistance of the water-based coating for wind turbine tower steel and is environmentally friendly. At the same time, it solves the problems of the inability to spray ultra-high film thickness and slow drying speed in the construction process of the coating, and can fully meet the performance requirements of harsh environments.

[0091] The water-based coating for wind turbine tower steel of the present invention achieves adhesion of 8 MPa or greater, a pencil hardness of 2H or greater, and excellent salt spray resistance through the design and compounding of various components. The coating passes a 2000-h neutral salt spray test, with unilateral corrosion expansion of 2 mm or less at the scratched area, and no blistering, rusting, or cracking in the unscratched area. The coating film thickness is 150-220 μm. When applied to steel, the coating can fully meet the requirements of use in harsh environments. DETAILED DESCRIPTION

[0092] For the convenience of understanding the present invention, the present invention is given below with examples. It should be understood by those skilled in the art that the examples are only for the purpose of helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0093] The raw material information involved in the specific implementation of the present invention is as follows:

[0094] Hydroxyl modified acrylic emulsion: number average molecular weight 30,000-40,000.

[0095] Carboxyl modified acrylic emulsion: number average molecular weight 2000-5000.

[0096] Epoxy emulsion: number average molecular weight 1000-4000.

[0097] Dodecyl-modified HDI prepolymer: NCO mass percentage is 8%, dodecyl mass percentage is 2%.

[0098] Polyoxypropylene modified HDI prepolymer: NCO mass percentage is 8%, polyoxypropylene mass percentage is 2%.

[0099] Polysiloxane modified HDI prepolymer: NCO mass percentage is 8%, polysiloxane acid group mass percentage is 2%.

[0100] Dodecyl-modified NX-8401: The mass percentage of amino group is 7%, and the mass percentage of dodecyl group is 2%.

[0101] Perfluorooctyl modified NX-8401: The mass percentage of amino group is 7%, and the mass percentage of perfluorooctyl group is 2%.

[0102] Cyclohexyl-modified NX-8401: The mass percentage of amino group is 7%, and the mass percentage of cyclohexyl group is 2%.

[0103] Functional silane coupling agent: aminosilane / epoxysilane.

[0104] Graphene: sheet diameter is 1-10μm.

[0105] Glass flake: flake diameter is 20-200μm.

[0106] Silicon dioxide: particle size is 10-100nm.

[0107] Wetting agent: sodium lauryl sulfate.

[0108] Rheology additives: UR 1120.

[0109] Defoamer: BYK-017.

[0110] Dispersant: BYK-2061H.

[0111] Color paste: Mayer Chemical Dinard series water-based industrial paint color, Black L130 (carbon black).

[0112] Example 1

[0113] A water-based coating for wind turbine tower steel and a preparation method thereof, wherein the water-based coating for wind turbine tower steel comprises the following components in parts by weight:

[0114] Component A:

[0115]

[0116]

[0117] Component B:

[0118] 20 parts of dodecyl-modified HDI prepolymer.

[0119] The preparation method of the water-based coating for wind power tower steel is as follows:

[0120] According to the above formula and dosage, the hydroxyl-modified acrylic emulsion, epoxy emulsion and dodecyl-modified NX-8401 were mixed in a high-speed disperser at 1000 r / min for 40 minutes, and aminosilane, silica, glass flakes, aluminum tripolyphosphate and dispersant were added thereto, and mixed at 1500 r / min for 60 minutes. Then, a wetting agent, a rheological additive and a defoaming agent were added and mixed at 1200 r / min for 20 minutes, and then the color paste was added and mixed evenly, and allowed to stand for 20 minutes to obtain component A;

[0121] Component A and component B are mixed evenly to obtain the water-based coating for wind turbine tower steel.

[0122] Example 2

[0123] A water-based coating for wind turbine tower steel and a preparation method thereof, wherein the water-based coating for wind turbine tower steel comprises the following components in parts by weight:

[0124] Component A:

[0125]

[0126] Component B:

[0127] 30 parts of polyoxypropylene modified HDI prepolymer.

[0128] The preparation method of the water-based coating for wind power tower steel is as follows:

[0129] According to the above formula and dosage, the hydroxyl-modified acrylic emulsion, epoxy emulsion and perfluorooctyl-modified NX-8401 were mixed in a high-speed disperser at 800 r / min for 20 minutes, epoxy silane, silica, mica powder, aluminum tripolyphosphate and dispersant were added thereto, and mixed at 1000 r / min for 30 minutes, and then a wetting agent, a rheological additive and a defoaming agent were added and mixed at 800 r / min for 30 minutes, and then a color paste was added and mixed evenly, and allowed to stand for 10 minutes to obtain component A;

[0130] Component A and component B are mixed evenly to obtain the water-based coating for wind turbine tower steel.

[0131] Example 3

[0132] A water-based coating for wind turbine tower steel and a preparation method thereof, wherein the water-based coating for wind turbine tower steel comprises the following components in parts by weight:

[0133] Component A:

[0134]

[0135] Component B:

[0136] 5 parts of polysiloxane-modified HDI prepolymer.

[0137] The preparation method of the water-based coating for wind power tower steel is as follows:

[0138] According to the above formula and dosage, the hydroxyl-modified acrylic emulsion, epoxy emulsion and cyclohexyl-modified NX-8401 were mixed in a high-speed disperser at 1200 r / min for 10 minutes, and aminosilane, silica, graphene, aluminum tripolyphosphate and dispersant were added thereto, and mixed at 2000 r / min for 90 minutes. Then, a wetting agent, a rheological additive and a defoaming agent were added and mixed at 1500 r / min for 5 minutes, and then the color paste was added and mixed evenly, and allowed to stand for 30 minutes to obtain component A;

[0139] Component A and component B are mixed evenly to obtain the water-based coating for wind turbine tower steel.

[0140] Example 4

[0141] A water-based coating for wind turbine tower steel, which differs from Example 1 only in that the water-based coating for wind turbine tower steel contains 5 parts of hydroxyl-modified acrylic emulsion and 5 parts of carboxyl-modified acrylic emulsion, and other components, amounts and preparation methods are the same as those in Example 1.

[0142] Comparative Example 1

[0143] A water-based coating for wind turbine tower steel, which differs from Example 1 only in that the hydroxyl-modified acrylic emulsion in Example 1 is replaced by an equal amount of acrylic emulsion, and the other components, amounts and preparation methods are the same as those in Example 1.

[0144] Comparative Example 2

[0145] A water-based coating for wind turbine tower steel, which differs from Example 1 only in that the amount of epoxy emulsion used is 15 parts, and the other components, amounts and preparation methods are the same as those in Example 1.

[0146] Comparative Example 3

[0147] A water-based coating for wind turbine tower steel, which differs from Example 1 only in that the amount of epoxy emulsion used is 115 parts, and the other components, amounts and preparation methods are the same as those in Example 1.

[0148] Comparative Example 4

[0149] A water-based coating for wind turbine tower steel, which differs from Example 1 only in that no organic amine polymer modified with a hydrophobic group is added to the water-based coating for wind turbine tower steel, and other components, amounts and preparation methods are the same as those in Example 1.

[0150] Comparative Example 5

[0151] A water-based coating for wind turbine tower steel, which differs from Example 1 only in that the amount of dodecyl-modified NX-8401 in the water-based coating for wind turbine tower steel is 5 parts, and other components, amounts and preparation methods are the same as those in Example 1.

[0152] Comparative Example 6

[0153] A water-based coating for wind turbine tower steel, which differs from Example 1 only in that the amount of dodecyl-modified NX-8401 in the water-based coating for wind turbine tower steel is 60 parts, and the other components, amounts and preparation methods are the same as those in Example 1.

[0154] The wind turbine tower steel provided in the above examples and comparative examples is coated with water-based paint on the steel, and the specific method is as follows:

[0155] (1) Cleaning: Scrub with acetone solvent, then blow clean with compressed air, and use an angle grinder or wire brush to grind the weld burrs until they are smooth;

[0156] (2) Sandblasting: Use a small desktop sandblasting machine to sandblast the steel surface at a pressure of 0.7 MPa, a spray gun angle of 70°, and a distance of 250 mm from the surface to achieve Sa2.5 level;

[0157] (3) Surface activation: Use a zinc phosphate conversion solution with a pH value of 5.0 and a concentration of 4% to wipe the surface of the sandblasted steel to form a micro-nanoscale zinc phosphate film;

[0158] (4) High-pressure airless spraying was used to coat the wind turbine tower steel of the above-mentioned embodiment and comparative example with water-based coating on the surface of the activated steel at a pressure of 16 MPa and a nozzle diameter of 1.8 mm. The coating thickness was 200 μm and the steel was cured at 80° C. for 40 minutes.

[0159] Performance testing:

[0160] (1) Adhesion: Tested in accordance with GB / T5210-2006.

[0161] (2) Neutral salt spray test: The test is carried out in accordance with GB / T 1771-2007 (neutral salt spray NSS) to evaluate the coating's resistance to chloride ion corrosion.

[0162] (3) Pencil hardness: tested in accordance with GB / T6739-2006.

[0163] (4) Chemical corrosion resistance: Acidic environment: immersion in 5% H2SO4 solution for 240 hours; alkaline environment: immersion in 5% NaOH solution for 240 hours; solvent environment: diesel / engine oil rub resistance 100 times. Evaluation criteria: The sample is immersed in the three environments mentioned above. If the coating does not blister, peel, lose gloss, or swell, it is scored as "pass". If the coating blister, peel, lose gloss, or swell, it is scored as "fail".

[0164] The test data is shown in Table 1:

[0165] Table 1

[0166]

[0167] According to the performance test data in Table 1, the water-based coating for wind turbine tower steel provided by the present invention forms a network interpenetrating structure through multiple cross-linking between modified acrylic emulsion, epoxy emulsion, hydrophobic group-modified isocyanate prepolymer and hydrophobic group-modified organic amine polymer, which significantly improves the adhesion and corrosion resistance of the water-based coating for wind turbine tower steel, while having the characteristics of environmental protection and fast drying speed; the adhesion of the water-based coating for wind turbine tower steel reaches ≥8MPa, the pencil hardness is ≥2H, and it has excellent salt spray resistance. After a 2000h neutral salt spray test, the unilateral corrosion expansion at the scratch is ≤2mm, and there is no blistering, rusting or cracking in the unscratched area. The coating film thickness is 150-220μm. When applied to steel, it can fully meet the use requirements of harsh environments.

[0168] It can be seen from Example 1 and Comparative Example 1 that if ordinary acrylic emulsion is used, the adhesion, salt spray resistance, hardness and chemical corrosion resistance of the coating will decrease.

[0169] It can be seen from Example 1 and Comparative Examples 2-3 that if the amount of epoxy emulsion is not within the specified range of the present invention, insufficient or excessive cross-linking network will be formed, the coating will be too hard or have insufficient adhesion, and both adhesion and chemical corrosion resistance cannot be taken into account at the same time.

[0170] It can be seen from Example 1 and Comparative Example 4 that if the organic amine polymer modified with hydrophobic groups is not added to the water-based coating for wind turbine tower steel, the coating cannot fully form a cross-linked network, resulting in a decrease in the adhesion, salt spray resistance and hardness of the coating.

[0171] It can be seen from Example 1 and Comparative Examples 5-6 that if the amount of organic amine polymer modified with hydrophobic groups in the water-based coating for wind turbine tower steel is not within the specified range of the present invention, it will lead to insufficient or excessive cross-linking network formation, the coating will be too hard or the adhesion will be insufficient, and it will not be possible to take into account both adhesion and chemical corrosion resistance at the same time.

[0172] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A water-based coating for wind turbine tower steel, characterized in that: The water-based coating for wind turbine tower steel comprises the following components in parts by weight: Component A: Component B: 5-30 parts of hydrophobic group-modified isocyanate prepolymer; The modified acrylic emulsion includes a hydroxyl-modified acrylic emulsion and optionally other modified acrylic emulsions; the other modified acrylic emulsions include a carboxyl-modified acrylic emulsion and / or a silicone-modified acrylic emulsion.

2. The water-based paint for wind turbine tower steel according to claim 1, characterized in that: The epoxy equivalent weight of the epoxy emulsion is 150-500 g / eq; Preferably, the mass percentage of NCO groups in the hydrophobic group-modified isocyanate prepolymer is 3-15%; Preferably, the mass percentage of the hydrophobic group in the hydrophobic group-modified isocyanate prepolymer is 0.05-5%; Preferably, the hydrophobic group in the hydrophobic group-modified isocyanate prepolymer includes any one of a dodecyl group, a polyoxypropylene group or a polysiloxane group; Preferably, the mass percentage of amino groups in the hydrophobic group-modified organic amine polymer is 0.5-10%; Preferably, the mass percentage of the hydrophobic group in the hydrophobic group-modified organic amine polymer is 0.5-10%; Preferably, the hydrophobic group in the hydrophobic group-modified organic amine polymer includes any one of dodecyl, perfluorooctyl or cyclohexyl.

3. The water-based paint for wind turbine tower steel according to claim 1 or 2, characterized in that: The adhesion promoter includes any one of a functional silane coupling agent, a titanate coupling agent or an acrylic acid phosphate ester, or a combination of at least two thereof; Preferably, the functional silane coupling agent includes any one or a combination of at least two of an amino-modified silane coupling agent, an epoxy-modified silane coupling agent, a mercapto-modified silane coupling agent or a siloxane-grafted silane coupling agent; Preferably, the flaky filler comprises any one of graphene, mica or glass flakes or a combination of at least two thereof; Preferably, the flake filler has a diameter of 1-200 μm; Preferably, the salt spray resistant filler comprises aluminum tripolyphosphate and optionally other salt spray resistant fillers; Preferably, the other salt spray resistant fillers include any one of tripolyphosphates, aluminum zinc phosphomolybdates or zinc powder, or a combination of at least two of them.

4. The water-based paint for wind turbine tower steel according to any one of claims 1 to 3, characterized in that: The water-based coating for wind turbine tower steel further comprises any one or a combination of at least two of a reinforcing agent, a wetting agent, a rheological additive, a defoaming agent or a dispersant; Preferably, the amount of the reinforcing agent, wetting agent, rheological additive, defoaming agent or dispersant in the water-based coating for wind turbine tower steel is independently 1-10 parts; Preferably, the reinforcing agent comprises any one of titanium dioxide, silicon dioxide or aluminum oxide, or a combination of at least two thereof; Preferably, the wetting agent comprises sodium lauryl sulfate and / or polyether-modified polysiloxane; Preferably, the rheological additive comprises any one of polyurea, bentonite or silica, or a combination of at least two thereof; Preferably, the defoaming agent comprises any one of an organosilicon defoaming agent, a polyether defoaming agent or a mineral oil defoaming agent, or a combination of at least two thereof; Preferably, the dispersant comprises any one or a combination of at least two of a modified phosphate dispersant, a maleic anhydride modified dispersant or a functional block copolymer dispersant; Preferably, the dispersant includes any one of isooctyl polyoxyethylene ether phosphate, maleic anhydride-acrylate copolymer, or polyester-polyethylene glycol block copolymer, or a combination of at least two thereof.

5. The water-based paint for wind turbine tower steel according to any one of claims 1 to 4, characterized in that: The water-based paint for wind turbine tower steel also includes 50-100 parts of color paste.

6. A method for preparing a water-based coating for wind turbine tower steel according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: The modified acrylic emulsion, epoxy emulsion, hydrophobic group-modified organic amine polymer, adhesion promoter, flaky filler and salt spray resistant filler are uniformly mixed to obtain component A; Component A and component B are mixed evenly to obtain the water-based coating for wind turbine tower steel.

7. The preparation method according to claim 6, characterized in that The materials mixed in the component A further include any one or a combination of at least two of a reinforcing agent, a wetting agent, a rheological additive, a defoaming agent, a dispersant or a color paste; Preferably, the preparation method of the water-based coating for wind turbine tower steel comprises: first mixing a modified acrylic emulsion, an epoxy emulsion, and a hydrophobic group-modified organic amine polymer, adding an adhesion promoter, a flaky filler, a salt spray-resistant filler, a reinforcing agent, and a dispersant thereto, performing a second mixing, then adding a wetting agent, a rheological additive, and a defoaming agent, performing a third mixing, and then adding a color paste and mixing uniformly, and standing to obtain component A; Mixing component A and component B evenly to obtain the water-based coating for wind turbine tower steel; Preferably, the mixing equipment is a high-speed disperser; Preferably, the rotation speed of the first mixing is 800-1200 r / min; Preferably, the first mixing time is 20-60 min; Preferably, the second mixing speed is 1000-2000 r / min; Preferably, the second mixing time is 30-90 min; Preferably, the rotation speed of the third mixing is 800-1500 r / min; Preferably, the third mixing time is 5-30 min; Preferably, the standing time is 10-30 minutes.

8. The preparation method according to claim 6 or 7, characterized in that The method for preparing the water-based coating for wind turbine tower steel specifically comprises the following steps: A modified acrylic emulsion, an epoxy emulsion, and an organic amine polymer modified with a hydrophobic group are mixed in a high-speed disperser at 800-1200 r / min for 20-60 min, an adhesion promoter, a flaky filler, a salt spray resistant filler, a reinforcing agent, and a dispersant are added thereto, and the mixture is mixed at 1000-2000 r / min for 30-90 min, and then a wetting agent, a rheological additive, and a defoaming agent are added, and the mixture is mixed at 800-1500 r / min for 5-30 min, and then a color paste is added and mixed uniformly, and the mixture is allowed to stand for 10-30 min to obtain component A; Component A and component B are mixed evenly to obtain the water-based coating for wind turbine tower steel.

9. A method for applying a water-based coating for wind turbine tower steel according to any one of claims 1 to 5, characterized in that: The application method comprises the following steps: Applying the water-based paint on the surface of the wind turbine tower steel and curing the paint; Preferably, the steel material is pretreated before coating; Preferably, the pretreatment includes the steps of cleaning, sandblasting and surface activation; Preferably, the surface activation comprises: treating the sandblasted steel material with a zinc phosphate conversion solution; Preferably, the concentration of the zinc phosphate conversion solution is 3-5%; Preferably, the pH value of the zinc phosphate conversion solution is 4.5-5.

5.

10. The application method according to claim 9, characterized in that: The coating is carried out by high-pressure airless spraying; Preferably, the pressure of the high-pressure airless spraying is 14-22 MPa; Preferably, the nozzle diameter of the high-pressure airless spraying is 0.8-2.5 mm; Preferably, the coating has a thickness of 150-220 μm; Preferably, the curing temperature is 60-100°C; Preferably, the curing time is 20-60 minutes.

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