A room temperature self-drying water-based aluminum powder high temperature resistant coating and its preparation method and application

Abstract

The invention discloses a room temperature self-drying water-based aluminum powder high temperature resistant coating and its preparation method and application. The room temperature self-drying water-based aluminum powder high temperature resistant coating comprises, by mass percentage: 50-60% of a mixed emulsion of a water-based organic silicone emulsion and a silicone acrylic emulsion; 16-24% of a water-based aluminum silver paste slurry; 1.2-3% of a film-forming aid; 0.6-1.2% of a dispersant; 0.2-0.4% of a defoamer; 2%-4% of a rheological aid; 0-14% of a high temperature resistant filler and / or an anti-rust pigment; 0.2-0.4% of a substrate wetting agent; 0.6-1.2% of an anti-flash rust agent; 0.1-0.3% of a preservative; 0.6-2% of a drying agent; and deionized water: make up the balance. The present invention uses a mixed emulsion of water-based silicone emulsion and silicone acrylic emulsion as a film-forming substance, adds water-based aluminum silver paste slurry, and is supplemented with additives such as rheological additives, anti-flash rust agents and drying agents. The prepared coating can be dried at room temperature, is resistant to high temperatures of 600°C, has high coating hardness, and has excellent mechanical properties and anti-corrosion properties.

Description

Technical Field

[0001] The invention belongs to the technical field of high temperature resistant coatings, and specifically relates to a room temperature self-drying water-based aluminum powder high temperature resistant coating and a preparation method and application thereof. Background Art

[0002] In recent years, with the vigorous promotion of national environmental protection policies, environmentally friendly water-based paints have become the only way for many coatings industries to develop and transform, and water-based paints have also ushered in rapid development. Aluminum powder paint plays a very important role in the coating field due to its unique angle-dependent color effect, metallic texture and high-end luxurious visual effects. Therefore, green and environmentally friendly water-based aluminum powder paint has begun to gradually replace highly polluting solvent-based aluminum powder paint and become a new choice of the times.

[0003] Water-based aluminum powder high temperature resistant coating can withstand temperatures above 200°C for a long time, and can maintain physical and chemical properties, protect the coated object in a high temperature environment for a long service life, and is widely applied to the surfaces of high temperature pipes, chimney pipes, boiler tanks, engines and rotary kilns. At present, the coating of water-based aluminum powder high temperature resistant coating basically needs high temperature curing to have a good anti-corrosion effect. In fact, some large equipment and components are large in size, and basically cannot achieve complete high temperature curing of the coating. Before the equipment and components are operated at high temperature, if it rains, the corrosion resistance of the coating that has not been cured at high temperature is poor, and it is very easy to rust. In view of the problem that the coating of the current water-based aluminum powder high temperature resistant coating cannot dry at room temperature after construction and has poor corrosion resistance, the present invention aims to develop a water-based aluminum powder high temperature resistant paint that dries at room temperature, so that the equipment and components have a longer service life under the protection of the coating. Summary of the invention

[0004] In view of the technical defect that the coating in the prior art needs high-temperature baking to solidify into a film, the purpose of the present invention is to provide a room-temperature self-drying water-based aluminum powder high-temperature resistant coating and a preparation method and application thereof.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A room temperature self-drying water-based aluminum powder high temperature resistant coating, comprising the following components by mass percentage:

[0007] Mixed emulsion of water-based silicone emulsion and silicone acrylic emulsion: 50.0-60.0%;

[0008] Water-based aluminum silver paste: 16.0-24.0%;

[0009] Film-forming aid: 1.2-3.0%;

[0010] Dispersant: 0.6-1.2%;

[0011] Defoaming agent: 0.2-0.4%;

[0012] Rheological additive: 2% to 4%;

[0013] High temperature resistant filler and / or anti-rust pigment: 0-14.0%;

[0014] Substrate wetting agent: 0.2-0.4%;

[0015] Anti-flash rust agent: 0.6-1.2%;

[0016] Preservatives: 0.1-0.3%;

[0017] Drier: 0.6-2%;

[0018] Deionized water: Make up the balance.

[0019] Furthermore, in the mixed emulsion of the aqueous organic silicone emulsion and the silicone acrylic emulsion, the mass ratio of the aqueous organic silicone emulsion to the silicone acrylic emulsion is (2-3):1.

[0020] Furthermore, the particle size of the aqueous aluminum-silver paste is greater than 15 μm.

[0021] Furthermore, measured by mass percentage, the room temperature self-drying water-based aluminum powder high temperature resistant coating includes a mixed emulsion of water-based silicone emulsion and silicone acrylic emulsion: 55.0-58.0%; water-based aluminum silver paste slurry: 18.0-20.3%; film-forming aid: 1.6-2.0%; dispersant: 0.9-1.0%; defoaming agent: 0.3-0.35%; rheological aid: 2.4%-3.0%; high temperature resistant filler and / or anti-rust pigment: 6.0-13.0%; substrate wetting agent: 0.25-0.3%; anti-flash rust agent: 0.8-1.0%; preservative: 0.15-0.2%; drying agent: 0.8-1.0%; deionized water: make up the balance.

[0022] Furthermore, the high temperature resistant filler is low melting point glass powder and / or silica sol; and the anti-rust pigment is zinc phosphate.

[0023] Furthermore, the low-melting-point glass powder includes low-melting-point glass powders with different melting points, and the silica sol is silica sol surface-modified by an epoxy silane coupling agent.

[0024] Furthermore, the rheological additive includes a polyamide wax slurry rheological additive and a polyurethane rheological additive, and the mass ratio of the polyamide wax slurry rheological additive to the polyurethane rheological additive is (1-3): (0.3-1.2).

[0025] The present invention also provides a method for preparing the above-mentioned room temperature self-drying water-based aluminum powder high temperature resistant coating, comprising the following steps:

[0026] (1) Weigh each component according to the mass ratio;

[0027] (2) dispersing the dispersant, the defoamer, and a certain amount of the rheological additive in an appropriate amount of deionized water under low-speed stirring to obtain a first mixed solution;

[0028] (3) adding a high temperature resistant filler and / or an anti-rust pigment to the first mixed solution under low speed stirring and dispersing the mixture evenly to obtain a second mixed solution;

[0029] (4) adding silicone acrylic emulsion, water-based organosilicon emulsion, film-forming aid, substrate wetting agent, drying agent, flash rust inhibitor, and preservative to the second mixed solution under low-speed stirring and dispersing evenly to obtain a third mixed solution;

[0030] (5) adding water-based aluminum silver paste, the remaining rheological additive and deionized water to the third mixed liquid under low-speed stirring, and dispersing the mixture evenly to obtain a room-temperature self-drying water-based aluminum powder high-temperature resistant coating.

[0031] Furthermore, the rotation speed of the low-speed stirring in step (2) is 600-1000 r / min, the rotation speed of the low-speed stirring in step (3) is 800-1200 r / min, and the stirring time is 30-40 min; the rotation speed of the low-speed stirring in step (4) is 600-1000 r / min, and the stirring time is 15-20 min; the rotation speed of the low-speed stirring in step (5) is 600-800 r / min, and the stirring time is 15-20 min.

[0032] The present invention also provides a use of the above-mentioned room temperature self-drying water-based aluminum powder high temperature resistant coating or the room temperature self-drying high temperature resistant coating prepared by the above-mentioned preparation method in high temperature protection treatment of metal substrates, such as applying the above-mentioned coating to the surface of the metal substrate and curing it at room temperature to form a coating; the metal substrate can be a rotary kiln, an engine, a high temperature pipeline, an exhaust pipe, etc.

[0033] The beneficial effects of the present invention are:

[0034] (1) The present invention uses a mixed emulsion of water-based organic silicone emulsion and silicone acrylic emulsion as a film-forming substance, adds a water-based aluminum silver paste slurry, and is supplemented with additives such as a rheological additive, an anti-flash rust agent, and a drying agent. The prepared room-temperature self-drying water-based aluminum powder high-temperature resistant coating can be dried at room temperature, is resistant to high temperatures of 600°C, has a high coating hardness, and has excellent mechanical properties and anti-corrosion properties.

[0035] (2) The present invention significantly improves the stress of the coating film by using an aqueous aluminum-silver paste with a particle size greater than 15 μm, thereby improving the sudden cooling resistance of the coating film after coating.

[0036] (3) The present invention reasonably sets the mass ratio of the water-based silicone emulsion and the silicone-acrylic emulsion, so that the prepared coating can dry at room temperature and has good high temperature resistance.

[0037] (4) The present invention not only improves the corrosion resistance and high temperature resistance by adding high temperature resistant fillers and / or anti-rust pigments, but also shortens the surface drying and actual drying time of the coating film to a certain extent. DETAILED DESCRIPTION

[0038] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] On the one hand, the room temperature self-drying water-based aluminum powder high temperature resistant coating provided by an embodiment of the present invention includes the following components, measured by mass percentage: a mixed emulsion of water-based silicone emulsion and silicone acrylic emulsion: 50.0-60.0%; water-based aluminum silver paste slurry: 16.0-24.0%; film-forming aid: 1.2-3.0%; dispersant: 0.6-1.2%; defoaming agent: 0.2-0.4%; rheological aid: 2%-4%; high temperature resistant filler: 0-14.0%; anti-rust pigment: 0-9.0%; substrate wetting agent: 0.2-0.4%; anti-flash rust agent: 0.6-1.2%; preservative: 0.1-0.3%; drying agent: 0.6-2%; deionized water: make up the balance.

[0040] In some preferred embodiments, in the mixed emulsion of the aqueous organosilicon emulsion and the silicone-acrylic emulsion, the mass ratio of the aqueous organosilicon emulsion to the silicone-acrylic emulsion is (2-3):1.

[0041] In some preferred embodiments, the room temperature self-drying water-based aluminum powder high temperature resistant coating includes, by mass percentage, a mixed emulsion of water-based silicone emulsion and silicone acrylic emulsion: 55.0-58.0%; water-based aluminum silver paste slurry: 18.0-20.3%; film-forming aid: 1.6-2.0%; dispersant: 0.9-1.0%; defoaming agent: 0.3-0.35%; rheological aid: 2.4%-3.0%; high temperature resistant filler and / or anti-rust pigment: 6.0-13.0%; substrate wetting agent: 0.25-0.3%; anti-flash rust agent: 0.8-1.0%; preservative: 0.15-0.2%; drying agent: 0.8-1.0%; deionized water: make up the balance.

[0042] In the preferred embodiment of the present invention, an emulsion formed by mixing water-based silicone emulsion and silicone-acrylic emulsion in a certain mass ratio is used as a film-forming substance, wherein the water-based silicone emulsion is a polymethyl / phenylsiloxane trifunctional branched structure, and the side chain functional groups and main chain in the silicone resin are destroyed at high temperature, and are completely converted into an inorganic siloxane structure, and active sites are formed at the fracture to interact with the pigments and fillers in the system, and secondary film formation occurs to form a denser coating film, so that the formed inorganic siloxane structure has a higher cross-linking density, excellent high temperature resistance, and reduces the drying temperature and time to a certain extent. Silicone-acrylic emulsion combines the high temperature resistance, weather resistance, chemical resistance, hydrophobicity of silicone resin and the high color retention, flexibility, and adhesion of acrylic resin, and is a highly weather-resistant, highly water-resistant, and anti-pollution emulsion; at the same time, the VOC content of water-based silicone emulsion and silicone-acrylic emulsion is low, and the use of the two emulsions can promote the room temperature drying of the coating.

[0043] Furthermore, the high temperature resistant filler is a low melting point glass powder with different melting points, such as PE-450 and PE-550. The organic groups in the silicone resin gradually decompose at high temperature to form an inorganic silicon oxygen cross-linked structure, which has poor corrosion resistance; the low melting point glass powder has a low melting point, and after melting at high temperature, it replaces the silicone resin to play an adhesion role on the color filler, and then forms a siliconized layer, so that the coating is film-formed for the second time, which not only improves the anti-corrosion effect of the coating on the substrate, but also improves the high temperature resistance and heat insulation to a certain extent; silica sol has the advantages of good adhesion, high temperature resistance, and high specific surface area; silica sol surface treated with epoxy silane coupling agent has good stability in water-based coatings, and can also improve the basic properties of the coating film. In the preferred embodiment of the present invention, silica sol surface treated with epoxy silane coupling agent is used. The anti-rust pigment is high-purity zinc phosphate, which is non-toxic, pollution-free, and has good thermal stability.

[0044] The melting point of aluminum with a purity of 99.5% is 685°C. The aluminum paste coated with silicon dioxide can be dispersed in water, has good water resistance, extremely low gas release, excellent weather resistance and temperature resistance; the coarser the aluminum paste particles and the higher the reflective ratio, the brighter and whiter it is, the higher the flash index, and the better the angle-dependent color effect; the finer the particles, the more irregular the particle structure, the higher the proportion of scattered light, the more uniform and soft it looks, the higher the hiding power, and the better the vividness. However, aluminum pastes of different particle sizes have different effects on the stress of the coating, thereby affecting the resistance to sudden cooling. After continuous exploration by the inventors, it was found that aluminum pastes with a particle size greater than 15 μm can better improve the stress of the coating, thereby making the coating have better resistance to sudden cooling. Further, the particle size of the water-based aluminum paste slurry used in the embodiment of the present invention is greater than 15 μm. In some preferred embodiments, the particle size of the water-based aluminum paste slurry is 25 to 54 μm.

[0045] Since aluminum pigment has a large diameter-to-thickness ratio and high density, it is very easy to settle. Its arrangement and orientation in the paint film are greatly affected by the rheological behavior of the paint. Adding an appropriate amount of rheological additives to the formula can effectively improve the rheological properties of the system. Polyamide wax slurry rheological additives have a strong anchoring effect on aluminum pigments. The special hydrogen bond structure makes the system form a three-dimensional network structure, which limits the movement and tumbling of aluminum powder caused by the Bénard vortex caused by temperature difference, surface tension and density during the drying of the wet film, so that the aluminum powder is better oriented; at the same time, the system produces appropriate thixotropy, so that the coating has shear thinning characteristics. Polyurethane rheological additives are special "lipophilic-hydrophilic-lipophilic" triblock polymer structures. The hydrophilic group is coupled with the hydrophilic group in the system, and the lipophilic end is adsorbed on different micelle particles to form bridges between particles. It associates with the polymer particles of the emulsion and the pigment particles that have been adsorbed with dispersants to form a network structure, and they are connected and entangled with each other to increase the viscosity of the system, which has a good stabilizing effect. In some preferred embodiments, the rheological additive comprises a polyamide wax rheological additive and a polyurethane rheological additive, and the mass ratio of the polyamide wax rheological additive to the polyurethane rheological additive is (1-3): (0.3-1.2).

[0046] In some preferred embodiments, ethylene glycol butyl ether is used to disperse aluminum silver paste to prepare aluminum silver paste slurry, and ethylene glycol butyl ether can also form film-forming aids with different boiling points with 12-ester alcohol in the coating system, which can not only ensure the dry rate of the coating, but also enable the coating to have better film-forming properties.

[0047] In some preferred embodiments, the drying agent is a titanate catalyst, and the addition of an appropriate amount makes the coating film have better drying properties and better flexibility; the anti-rust agent is Ascotan-H10, which has excellent anti-rust properties on various metal substrates and good compatibility with the emulsion; the substrate wetting agent is a silicone twin structure surfactant, which can promote flow, low foam, low foaming and anti-shrinkage; the preservative is LEX is a highly effective and low-toxic bactericidal preservative, suitable for polymer emulsions, pigment slurries and various water-based coatings. The water-based system has poor wetting properties for pigments, so an appropriate amount of dispersant needs to be added to evenly disperse the aluminum powder, anti-rust pigments and high-temperature resistant fillers. The dispersant is DISPERBYK-192, which uses the electrostatic repulsion and steric hindrance of the dispersant to evenly suspend the aluminum powder and fillers in the resin carrier without sedimentation or aggregation; the defoamer is a silicone defoamer, which not only has good compatibility with the resin, but also can improve the high-temperature resistance of the coating.

[0048] On the other hand, an embodiment of the present invention further provides a method for preparing the above-mentioned room temperature self-drying water-based aluminum powder high temperature resistant coating, comprising the following steps:

[0049] (1) Weigh each component according to the mass ratio;

[0050] (2) at a speed of 600 to 1000 r / min, uniformly dispersing a dispersant, a defoaming agent, and a certain amount of a rheological additive in an appropriate amount of deionized water to obtain a first mixed solution;

[0051] (3) adding a high temperature resistant filler and / or an anti-rust pigment to the first mixed solution and dispersing the mixture for 30 to 40 minutes at a rotation speed of 800 to 1200 r / min to obtain a second mixed solution;

[0052] (4) adding silicone acrylic emulsion, water-based organosilicon emulsion, film-forming aid, substrate wetting agent, drying agent, flash rust inhibitor, and preservative to the second mixed solution at a rotation speed of 600 to 1000 r / min and dispersing for 15 to 20 minutes to obtain a third mixed solution;

[0053] (5) At a rotation speed of 600 to 800 r / min, add water-based aluminum silver paste, the remaining rheological additive and deionized water to the third mixed liquid, and disperse for 15 to 20 minutes to obtain a room temperature self-drying water-based aluminum powder high temperature resistant coating.

[0054] The present invention is further described in detail below through specific examples.

[0055] The silicone emulsion used in the following examples and comparative examples is brand Dowsil 8016, the silicone acrylic emulsion is brand ROSF-8899, the rheological additives are polyamide wax slurry 7802 rheological additives and polyurethane Borchi Gel 0620 rheological additives, and the defoamer is brand The silicone defoamer of Airex902W, the dispersant brand is DISPERBYK-192, and the film-forming aid is ester alcohol, the drying agent is titanate catalyst TITANIUM (IV), the anti-rust agent is Ascotan-H10, the substrate wetting agent is TEGO Twin4100, and the preservative is LEX, high temperature resistant filler is low melting point glass powder PE-450 and PE-550 with different melting points, silica sol is silica sol surface treated with epoxy silane coupling agent; water-based aluminum silver paste was purchased from Zuxing New Materials Co., Ltd., and the models are: ZW6215 (D50: 15μm), ZW1305 (D50: 25μm) and ZW2214 (D50: 54μm).

[0056] The preparation method of the aqueous aluminum-silver paste with different particle sizes of the present invention is as follows: because the morphology of the aluminum-silver paste is silver-dollar-shaped, the manufacturer's supply form is paste-shaped, and if a high-shear and high-speed dispersion method is adopted, the morphology and stability will be destroyed. Therefore, the present invention uses a paddle stirring and a low-speed dispersion method to pre-disperse the aluminum-silver paste: the aqueous aluminum-silver paste, ethylene glycol butyl ether and a dispersant with a mass ratio of 10:10:0.3 are sequentially added to a suitable dispersion container, and then stirred at 500-700r / min for 15-20min, and the scraper is tested for fineness and is ready for use.

[0057] Example 1

[0058] A room temperature self-drying water-based aluminum powder high temperature resistant coating comprises, by mass percentage, 40% of water-based silicone emulsion, 18% of silicone acrylic emulsion; 20.3% of water-based aluminum silver paste (D50: 54 μm); 1.6% of film-forming agent; 0.6% of dispersant; 0.2% of defoaming agent; 2% of polyamide wax paste rheological additive, 0.8% of polyurethane rheological additive; 0.2% of substrate wetting agent, 1% of anti-flash rust agent, 0.1% of preservative, 0.8% of drying agent and 14.4% of deionized water.

[0059] The preparation method of room temperature self-drying water-based aluminum powder high temperature resistant coating, the specific steps are as follows:

[0060] (1) Weigh each component according to mass ratio;

[0061] (2) adding a dispersant, a defoamer and a polyamide wax slurry rheology additive to an appropriate amount of deionized water in sequence under low-speed stirring, and uniformly dispersing the paste-like polyamide wax slurry at a speed of 600 to 1000 r / min to avoid the generation of a large number of bubbles in the system caused by high-speed stirring of the polyamide wax slurry after the late addition of the emulsion, and obtaining a first mixed solution after uniform dispersion;

[0062] (3) at a speed of 600 to 1000 r / min, slowly adding silicone acrylic emulsion, organosilicon emulsion, film-forming aid, substrate wetting agent, drying agent, flash rust inhibitor and preservative to the first mixed solution in sequence and dispersing for 20 minutes to obtain a second mixed solution;

[0063] (4) At a rotation speed of 600 to 800 r / min, water-based aluminum silver paste and polyurethane rheological additive are slowly added to the second mixed liquid in sequence to thicken the emulsion, adjust the overall viscosity of the system, and add enough deionized water to disperse for 15 minutes to obtain a room temperature self-drying water-based aluminum powder high temperature resistant coating.

[0064] Example 2

[0065] A room temperature self-drying water-based aluminum powder high temperature resistant coating was prepared according to the same ingredients and method as in Example 1, except that the particle size of the water-based aluminum silver paste was D50: 25 μm.

[0066] Example 3

[0067] A room temperature self-drying water-based aluminum powder high temperature resistant coating comprises, by mass percentage, 40% of water-based organic silicon emulsion, 18% of silicone acrylic emulsion; 20.3% of water-based aluminum silver paste (D50: 54 μm); 13% of silica sol, 1.6% of film-forming aid; 0.6% of dispersant; 0.2% of defoamer; 2% of polyamide wax paste rheological aid, 0.8% of polyurethane rheological aid; 0.2% of substrate wetting agent, 1% of anti-flash rust agent, 0.1% of preservative, 0.8% of drying agent and 1.4% of deionized water.

[0068] The preparation method of room temperature self-drying water-based aluminum powder high temperature resistant coating, the specific steps are as follows:

[0069] (1) Weigh each component according to mass ratio;

[0070] (2) adding a dispersant, a defoamer and a polyamide wax slurry rheology additive to the silica sol in sequence under low-speed stirring, and uniformly dispersing the paste-like polyamide wax slurry at a speed of 600 to 1000 r / min to avoid the generation of a large number of bubbles in the system caused by high-speed stirring of the polyamide wax slurry after the late addition of the emulsion, and obtaining a first mixed solution after uniform dispersion;

[0071] (3) at a speed of 600 to 1000 r / min, slowly adding silicone acrylic emulsion, organosilicon emulsion, film-forming aid, substrate wetting agent, drying agent, flash rust inhibitor and preservative to the first mixed solution in sequence and dispersing for 15 minutes to obtain a second mixed solution;

[0072] (4) At a rotation speed of 600 to 800 r / min, water-based aluminum silver paste and polyurethane rheological additive are slowly added to the second mixed liquid in sequence to thicken the emulsion and adjust the overall viscosity of the system. Deionized water is added to disperse for 20 minutes to obtain a room temperature self-drying water-based aluminum powder high temperature resistant coating.

[0073] Example 4

[0074] A room temperature self-drying water-based aluminum powder high temperature resistant coating comprises, by mass percentage, 40% of water-based organic silicon emulsion, 18% of silicone acrylic emulsion; 20.3% of water-based aluminum silver paste (D50: 54 μm); 6% of high-purity zinc phosphate, 1.6% of film-forming aid; 0.6% of dispersant; 0.2% of defoamer; 2% of polyamide wax paste rheological aid, 0.8% of polyurethane rheological aid; 0.2% of substrate wetting agent, 1% of anti-flash rust agent, 0.1% of preservative, 0.8% of drying agent and 8.4% of deionized water.

[0075] The preparation method of room temperature self-drying water-based aluminum powder high temperature resistant coating, the specific steps are as follows:

[0076] (1) Weigh each component according to mass ratio;

[0077] (2) adding a dispersant, a defoamer and a polyamide wax slurry rheology additive to an appropriate amount of deionized water in sequence under low-speed stirring, and uniformly dispersing the paste-like polyamide wax slurry at a speed of 600 to 1000 r / min to avoid the generation of a large number of bubbles in the system caused by high-speed stirring of the polyamide wax slurry after the late addition of the emulsion, and obtaining a first mixed solution after uniform dispersion;

[0078] (3) adding high-purity zinc phosphate to the first mixed solution at a rotation speed of 800 to 1200 r / min, dispersing for 30 to 40 minutes, and then grinding to a fineness of ≤30 μm to obtain a second mixed solution;

[0079] (4) at a speed of 600 to 1000 r / min, slowly adding silicone acrylic emulsion, organosilicon emulsion, film-forming aid, substrate wetting agent, drying agent, flash rust inhibitor and preservative to the second mixed solution in sequence and dispersing for 20 minutes to obtain a third mixed solution;

[0080] (5) At a rotation speed of 600 to 800 r / min, water-based aluminum silver paste and polyurethane rheological additive are slowly added to the third mixed liquid in sequence to thicken the emulsion, adjust the overall viscosity of the system, supplement the amount of deionized water and disperse for 15 to 20 minutes to obtain a room temperature self-drying water-based aluminum powder high temperature resistant coating.

[0081] Example 5

[0082] A room temperature self-drying water-based aluminum powder high temperature resistant coating comprises, by mass percentage, 40% of water-based organic silicon emulsion, 18% of silicone acrylic emulsion; 20.3% of water-based aluminum silver paste (D50: 54 μm); 8% of low melting point glass powder (PE-450: PE-550=1:1); 1.6% of film-forming aid; 0.6% of dispersant; 0.2% of defoaming agent; 2% of polyamide wax paste rheological aid, 0.8% of polyurethane rheological aid; 0.2% of substrate wetting agent, 1% of anti-flash rust agent, 0.1% of preservative, 0.8% of drying agent and 6.4% of deionized water.

[0083] The preparation method of room temperature self-drying water-based aluminum powder high temperature resistant coating, the specific steps are as follows:

[0084] (1) Weigh each component according to mass ratio;

[0085] (2) adding a dispersant, a defoamer and a polyamide wax slurry rheology additive to an appropriate amount of deionized water in sequence under low-speed stirring, and uniformly dispersing the paste-like polyamide wax slurry at a speed of 600 to 1000 r / min to avoid the generation of a large number of bubbles in the system caused by high-speed stirring of the polyamide wax slurry after the late addition of the emulsion, and obtaining a first mixed solution after uniform dispersion;

[0086] (3) adding low melting point glass powder to the first mixed solution at a rotation speed of 800 to 1200 r / min, dispersing for 30 to 40 minutes, and then grinding to a fineness of ≤30 μm to obtain a second mixed solution;

[0087] (4) at a speed of 600 to 1000 r / min, slowly adding silicone acrylic emulsion, organosilicon emulsion, film-forming aid, substrate wetting agent, drying agent, flash rust inhibitor and preservative to the second mixed solution in sequence and dispersing for 15 to 20 minutes to obtain a third mixed solution;

[0088] (5) At a rotation speed of 600 to 800 r / min, water-based aluminum silver paste and polyurethane rheological additive are slowly added to the third mixed liquid in sequence to thicken the emulsion, adjust the overall viscosity of the system, supplement the amount of deionized water and disperse for 15 to 20 minutes to obtain a room temperature self-drying water-based aluminum powder high temperature resistant coating.

[0089] Comparative Example 1

[0090] A room temperature self-drying water-based aluminum powder high temperature resistant coating was prepared according to the same ingredients and method as in Example 1, except that the particle size of the water-based aluminum silver paste was D50: 15 μm.

[0091] Comparative Example 2

[0092] A room temperature self-drying water-based aluminum powder high temperature resistant coating was prepared in the same manner as in Example 1, except that, in the composition of the coating, the mass percentage of the organic silicon emulsion was 30%, and the mass percentage of the silicone acrylic emulsion was 28%.

[0093] Comparative Example 3

[0094] A room temperature self-drying water-based aluminum powder high temperature resistant coating was prepared in the same manner as in Example 1, except that, in the composition of the coating, the mass percentage of the organic silicon emulsion was 0%, and the mass percentage of the silicone acrylic emulsion was 58%.

[0095] Comparative Example 4

[0096] A room temperature self-drying water-based aluminum powder high temperature resistant coating was prepared in the same manner as in Example 1, except that, in the composition of the coating, the mass percentage of the organic silicon emulsion was 58%, and the mass percentage of the silicone acrylic emulsion was 0%.

[0097] For the convenience of comparison, the raw material dosages of the above embodiments and comparative examples are listed, as shown in the following Table 1.

[0098] Table 1 Raw material dosage of each embodiment of the present invention and comparative example (%)

[0099]

[0100] Performance Test:

[0101] The coatings prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were used to prepare coating films on steel substrates. The test results of the coating film properties are shown in Table 2:

[0102] Table 2 Test results of coating film performance

[0103]

[0104]

[0105] From the table above we can see that:

[0106] 1. It can be seen from Example 1, Example 2 and Comparative Example 1 that the coating prepared by the aluminum-silver paste with a large D50 value has better resistance to sudden cooling; after the coating prepared by the aluminum-silver paste with different particle size values ​​is subjected to high temperature, due to the different effects of aluminum-silver pastes with different particle sizes on the stress of the coating, the aluminum-silver paste with a large D50 value (25-54um) can better improve the stress of the coating, so that the coating has better resistance to sudden cooling, while the coating prepared by the aluminum-silver paste with a small D50 value (15um) has edge cracking.

[0107] 2. It can be seen from Example 1 and Comparative Example 2 that only when the silicone emulsion in the mixed emulsion of water-based silicone emulsion and silicone acrylic emulsion reaches a certain amount of addition, the coating has good heat resistance. This is because the silicone emulsion forms sufficient active sites at the fracture under high temperature, so that the formed inorganic siloxane structure has a higher cross-linking density, and at the same time reacts with aluminum silver paste, etc., to form a more dense coating film with excellent high temperature resistance.

[0108] 3. It can be seen from Example 1, Comparative Example 3 and Comparative Example 4 that: if water-based organosilicon emulsion is used alone as a film-forming substance, although the coating has good anti-corrosion performance after being heat-resistant, the coating cannot be completely dried within 24 hours when dried at room temperature; if silicone-acrylic emulsion is used alone as a film-forming substance, although the coating has a faster surface drying and complete drying time when dried at room temperature, the coating is obviously powdered after being heat-resistant and has no anti-corrosion property; therefore, the mixed use of water-based organosilicon emulsion and silicone-acrylic emulsion can ensure that large equipment and components can be completely dried when dried at room temperature. If it rains or before operation, the coating has a certain anti-corrosion property, and after the operation, the coating has good high temperature resistance and anti-corrosion property after being subjected to high temperature.

[0109] 4. From Examples 1 to 5, it can be seen that the coatings have good corrosion resistance before and after high temperature, and the best one is Example 4. The film-forming substance of the high temperature resistant coating is a mixture of organic silicon emulsion and silicone acrylic emulsion. High temperature resistant pigments and fillers, such as aluminum silver paste, high purity zinc phosphate, silica sol, glass powder, etc., not only play the role of pigments and fillers, but also help the secondary film formation to improve the corrosion resistance, and to a certain extent shorten the surface drying and actual drying time of the coating.

[0110] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For matters that are not described in detail in some embodiments, reference may be made to the description in other embodiments.

[0111] The above-mentioned embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A room temperature self-drying water-based aluminum powder high temperature resistant coating, characterized in that: Calculated by mass percentage, it includes the following components: Mixed emulsion of water-based silicone emulsion and silicone acrylic emulsion: 50.0~60.0%; Water-based aluminum silver paste: 16.0~24.0%; Film-forming aid: 1.2~3.0%; Dispersant: 0.6~1.2%; Defoaming agent: 0.2~0.4%; Rheological additive: 2%~4%; High temperature resistant filler and / or anti-rust pigment: 0~14.0%; Substrate wetting agent: 0.2~0.4%; Anti-flash rust agent: 0.6~1.2%; Preservatives: 0.1~0.3%; Drier: 0.6~2%; Deionized water: make up the balance; Among them, the particle size D50 of the aqueous aluminum-silver paste is 25~54μm; in the mixed emulsion of the aqueous silicone emulsion and the silicone-acrylic emulsion, the mass ratio of the aqueous silicone emulsion to the silicone-acrylic emulsion is (2~3):

1.

2. The room temperature self-drying water-based aluminum powder high temperature resistant coating according to claim 1, characterized in that: Calculated by mass percentage, including mixed emulsion of water-based silicone emulsion and silicone-acrylic emulsion: 55.0~58.0%; Water-based aluminum silver paste: 18.0~20.3%; Film-forming aid: 1.6~2.0%; Dispersant: 0.9~1.0%; Defoaming agent: 0.3~0.35%; Rheological additives: 2.4%~3.0%; high temperature resistant fillers and / or anti-rust pigments: 6.0~13.0%; Substrate wetting agent: 0.25~0.3%; Anti-flash rust agent: 0.8~1.0%; Preservatives: 0.15~0.2%; Drier: 0.8~1.0%; Deionized water: Make up the balance.

3. The room temperature self-drying water-based aluminum powder high temperature resistant coating according to claim 1, characterized in that: The high temperature resistant filler is low melting point glass powder and / or silica sol; the anti-rust pigment is zinc phosphate.

4. The room temperature self-drying water-based aluminum powder high temperature resistant coating according to claim 3, characterized in that: The low-melting-point glass powder includes low-melting-point glass powders with different melting points, and the silica sol is silica sol surface-modified by an epoxy silane coupling agent.

5. The room temperature self-drying water-based aluminum powder high temperature resistant coating according to claim 1, characterized in that: The rheological additive comprises a polyamide wax slurry rheological additive and a polyurethane rheological additive; the mass ratio of the polyamide wax slurry rheological additive to the polyurethane rheological additive is (1-3): (0.3-1.2).

6. The method for preparing the room temperature self-drying water-based aluminum powder high temperature resistant coating according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Weigh each component according to the mass ratio; (2) Dispersing the dispersant, defoamer, and a certain amount of rheological additive in an appropriate amount of deionized water under low-speed stirring to obtain a first mixed solution; (3) adding a high temperature resistant filler and / or an anti-rust pigment to the first mixed solution under low speed stirring and dispersing the mixture evenly to obtain a second mixed solution; (4) adding silicone acrylic emulsion, water-based silicone emulsion, film-forming aid, substrate wetting agent, drying agent, flash rust inhibitor, and preservative to the second mixed liquid under low-speed stirring and dispersing the mixture evenly to obtain a third mixed liquid; (5) Adding water-based aluminum silver paste, the remaining amount of rheological additive and deionized water to the third mixed liquid under low-speed stirring, and dispersing evenly to obtain the room-temperature self-drying water-based aluminum powder high-temperature resistant coating.

7. The method for preparing the room temperature self-drying water-based aluminum powder high temperature resistant coating according to claim 6, characterized in that: The rotation speed of the low-speed stirring in step (2) is 600-1000 r / min, the rotation speed of the low-speed stirring in step (3) is 800-1200 r / min, and the stirring time is 30-40 min; the rotation speed of the low-speed stirring in step (4) is 600-1000 r / min, and the stirring time is 15-20 min; the rotation speed of the low-speed stirring in step (5) is 600-800 r / min, and the stirring time is 15-20 min.

8. Use of the room temperature self-drying water-based aluminum powder high temperature resistant coating according to any one of claims 1 to 5 or the room temperature self-drying high temperature resistant coating prepared by the preparation method of claim 6 in high temperature protection treatment of metal substrates.

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