Inorganic modified super-long salt-spray-resistant water-based paint and preparation method thereof

Abstract

The invention discloses an inorganic modified super-long salt-spray-resistant water-based paint and a preparation method thereof, and relates to the technical field of water-based industrial paints. The inorganic modified super-long salt-spray-resistant water-based paint at least comprises the following raw materials in parts by mass: 60-70 parts of water-based acrylic resin, 0.1-0.5 part of a bactericide, 0.2-0.4 part of a wetting agent, 0.5-1 part of a dispersing agent, 0.1-0.3 part of a defoaming agent, 0.5-1 part of a pH regulator, 8-12 parts of nano silicon dioxide coated polymerized calcium phosphate, 0.5-2 parts of modified zinc phosphate, 8-10 parts of silk mica powder, 2-4 parts of a coalescing agent and 10-20 parts of water. And 0.5 to 1 part of a polyurethane thickening agent. The inorganic modified super-long salt-fog-resistant water-based paint prepared by the invention has super-long salt fog resistance, high base material adhesion and low ion dissolution amount, and the hardness and water resistance of a coating are also improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of waterborne industrial coatings, in particular to an inorganic modified super-long salt spray resistant waterborne coating and a preparation method thereof. BACKGROUND

[0002] Materials are often corroded due to changes in humidity or acidity and alkalinity in the environment during use, so a coating is often sprayed on the surface of the material to prolong the service life of the material. The coating is generally prepared by mixing base resin, filler material and curing agent, etc. to form a coating, which is applied or sprayed on the surface of the material, and a layer of adhesive film is formed on the surface of the material after curing under certain conditions, which can isolate the material from water vapor, oxygen, acid and base in the air to achieve corrosion protection and protect the material.

[0003] With the increasing environmental awareness of people and the corresponding introduction of environmental protection regulations in various countries, waterborne anticorrosive industrial paint with low VOC emission has become the focus of attention. Compared with traditional solvent-based coatings, waterborne coatings have the advantages of low price, safe use, resource and energy saving, and reduction of environmental pollution and public hazards, and have become the main direction of the current development of the coating industry. Waterborne acrylic resin coating is the fastest growing and most diverse pollution-free coating among waterborne coatings. However, traditional waterborne acrylic resin coatings have strong hydrophilicity and poor coating density, and are prone to permeation corrosion in salt spray environment, with a salt spray resistance time usually less than 500 hours. Existing technologies mostly use chromate passivation or solvent-based epoxy systems, which have problems such as heavy metal pollution and VOC emission. Therefore, existing waterborne coatings have the defects of poor environmental protection, poor salt spray resistance and easy peeling, which greatly limits their use. SUMMARY

[0004] The present application aims to provide an inorganic modified super-long salt spray resistant waterborne coating and a preparation method thereof, which solves the following technical problems:

[0005] The existing acrylic waterborne coating coated on the surface of metal substrate has the problems of poor environmental protection, poor salt spray resistance and easy peeling.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] An inorganic modified super-long salt spray resistant waterborne coating, comprising at least the following mass parts of raw materials:

[0008] Water-based acrylic resin 60-70 parts, fungicide 0.1-0.5 parts, wetting agent 0.2-0.4 parts, dispersing agent 0.5-1 parts, defoaming agent 0.1-0.3 parts, PH regulator 0.5-1 parts, nano-silica coated polyphosphate calcium 8-12 parts, modified zinc phosphate 0.5-2 parts, mica powder 8-10 parts, film forming aid 2-4 parts, water 10-20 parts, polyurethane thickening agent 0.5-1 parts.

[0009] As a further scheme of the application: the preparation method of the modified zinc phosphate comprises the following steps:

[0010] Add zinc oxide to the ammonium carbonate-ammonia complex solution to obtain zinc carbonate sol;

[0011] Heat the zinc carbonate sol and dilute it in deionized water, age, filter, and wash to obtain zinc hydroxide wet gel;

[0012] Add the zinc hydroxide wet gel and cystine to anhydrous ethanol, and then add an ethanol solution of phosphoric acid, react, filter, wash, and dry to obtain modified zinc phosphate.

[0013] As a further scheme of the application: the mass ratio of the zinc hydroxide wet gel, the cystine, and the ethanol solution of phosphoric acid is 10:2-3:100-120, and the water content of the zinc hydroxide wet gel is 50-60%.

[0014] As a further scheme of the application: the mass ratio of the zinc oxide and the ammonium carbonate-ammonia complex solution is 10:100-120, and the PH value of the ammonium carbonate-ammonia complex solution is 9-10.

[0015] As a further scheme of the application: the mass fraction of ammonium carbonate in the ammonium carbonate-ammonia complex solution is 20-25%, the mass fraction of ammonia water is 25-28%, and the mass fraction of phosphoric acid in the ethanol solution of phosphoric acid is 10-15%.

[0016] As a further scheme of the application: the preparation method of the nano-silica coated polyphosphate calcium comprises the following steps:

[0017] Disperse calcium carbonate in deionized water, add phosphoric acid to react, concentrate, crystallize, dry, and calcine to obtain polyphosphate calcium;

[0018] Disperse the polyphosphate calcium in dilute hydrochloric acid, stir, wash, and dry to obtain activated polyphosphate calcium;

[0019] Add the activated polyphosphate calcium to the hydrolysis solution of gamma-aminopropyl triethoxysilane, react, wash, and dry to obtain coupling agent modified polyphosphate calcium;

[0020] The coupling agent modified cystine polymer calcium phosphate is dispersed in an ethanol / water solution, tetraethyl orthosilicate is added, ammonia water is added dropwise, and then reaction, washing and drying are carried out to obtain nano-silicon dioxide coated polymer calcium phosphate.

[0021] As a further scheme of the present application: the mass ratio of the calcium carbonate and the phosphoric acid is 1:5-6.

[0022] As a further scheme of the present application: the mass ratio of the activated polymer calcium phosphate, the gamma-aminopropyl triethoxysilane and the tetraethyl orthosilicate is 100:3-8:1-3.

[0023] As a further scheme of the present application: the bactericide is isothiazolinone, the wetting agent is one or a mixture of several of organic non-ionic wetting agent, polyacrylic acid aluminum salt or modified dihydroxy carboxylic acid salt compound, the dispersant is one or a mixture of several of anionic surfactant, bisamide dispersant, paraffin dispersant or organic metal salt dispersant, the defoaming agent is one of polyether defoaming agent or silicone defoaming agent, the PH regulator is one or a mixture of several of N, N-dimethyl ethanolamine, triethylamine, ammonia, triethanolamine, diethylamine, diethanolamine or 2-amino-2-methyl-1-propanol, and the film forming aid is one or a mixture of several of diethylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol phenyl ether or dodecanol ester.

[0024] A preparation method of inorganic modified super-long salt fog resistant water-based paint, at least comprising the following preparation steps:

[0025] The water-based acrylic resin, the bactericide, the wetting agent, the dispersant, the defoaming agent, the PH regulator, the nano-silicon dioxide coated polymer calcium phosphate, the modified zinc phosphate, the muscovite powder, the film forming aid, water and the polyurethane thickening agent are added into a basket sand mill for mixing and grinding until the maximum particle size is less than or equal to 20 microns to obtain the inorganic modified super-long salt fog resistant water-based paint.

[0026] The present application has the following beneficial effects:

[0027] The water-based paint provided by the application is a water-based single-component paint, which is an excellent one-coat paint, and the coating is dried at room temperature after painting, which is convenient to paint, environmentally friendly and safe to use, and is widely used in the fields of building, wood, metal and the like. The application selects water-based acrylic resin as the base resin to provide adhesion and film-forming property, adds modified zinc phosphate and nano-silica coated polyphosphoric acid calcium as the anti-rust pigment, which can improve the salt spray resistance and adhesion of the water-based paint, prolong the service life of the coating, and adds sericite as the filler to prolong the penetration path of the corrosion medium and further improve the corrosion resistance of the water-based paint. The inorganic modified super-long salt spray resistant water-based paint prepared by the application improves the salt spray resistance of the water-based paint to more than 1500 hours, and the VOC content is lower than the environmental protection standard, which can replace solvent-based paint for heavy-duty corrosion protection field, and has significant economic and environmental benefits.

[0028] In the application, the modified zinc phosphate in the paint is cystine modified zinc phosphate. The zinc phosphate is in a lamellar form in the coating, can form a dense film, and plays a physical shielding role, effectively shielding external corrosion media such as oxygen, moisture and chloride ions, thereby reducing the penetration of corrosion factors and reducing the corrosion rate. After the zinc phosphate is modified by cystine, the zinc phosphate has a more uniform sheet structure, forms a parallel superposition mode in the coating, creates a "labyrinth effect" that is difficult to penetrate, significantly prolongs and increases the path length and complexity of potential penetrants. At the same time, the cystine modification improves the dispersibility of the zinc phosphate in the water-based acrylic resin, which also helps to reduce the pores and defects in the coating, increase the uniformity and density of the coating surface, and improve the electrochemical stability and corrosion resistance of the coating. The cystine molecule contains active groups such as thiol and carboxyl groups, which can chemically react with active sites on the metal surface to form stable complexes or passivation films, thereby reducing the charge density and potential difference on the metal surface, reducing metal dissolution and ion migration, and prolonging the service life of the metal. In addition, when the cystine modified zinc phosphate encounters defects in the coating, it can release phosphate substances and combine with the metal substrate surface to form a protective film, effectively inhibiting the occurrence of metal corrosion and improving the salt spray resistance of the coating.

[0029] The application also introduces nano-silicon dioxide coated polymeric calcium phosphate in the coating, and the polymeric phosphate released from the polymeric calcium phosphate has very strong ion capture ability, can cross-chelate with metal ions, form very dense and hard chelate and be adsorbed on the substrate, effectively seal the metal ions, passivate the metal surface, achieve the chemical corrosion prevention effect, and prevent the corrosion process. Then, with the infiltration of water, the formed chelate slowly decomposes and converts into a phosphate coating film, which isolates air and water, and achieves the physical corrosion prevention effect. The polymeric calcium phosphate prepared by the application has excellent salt fog resistance, and still has super-long salt fog resistance under the condition of reducing the amount of zinc phosphate. In the application, the modified zinc phosphate and nano-calcium dioxide coated polymeric calcium phosphate synergistically improve the salt fog resistance of the coating, reduce the toxicity of zinc salt emission, and at the same time, the nano-silicon dioxide coating reduces the dissolution of calcium ions and improves the environmental protection performance. The nano-silicon dioxide coated on the surface of the polymeric calcium phosphate forms a chemical bonding inorganic network with the water-based acrylic resin, enhances the hardness, wear resistance, corrosion resistance and adhesion of the coating, and through the inorganic-organic synergistic effect, significantly improves the salt fog resistance, hydrolysis resistance and mechanical strength of the coating, and is suitable for high-end corrosion prevention and functional material field. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the application will be described below in a clear and complete manner. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0031] The preparation method of the modified zinc phosphate in Embodiment 1 includes the following steps:

[0032] 100g of zinc oxide is added to 1000mL of an ammonium carbonate-ammonia water compound solution to dissolve the zinc oxide, wherein the mass fraction of ammonium carbonate in the ammonium carbonate-ammonia water compound solution is 25%, and the mass fraction of ammonia water is 25%, to obtain a zinc carbonate sol.

[0033] 1000mL of the above zinc carbonate sol is placed in a 70℃ water bath, heated and stirred, until the solution becomes slightly turbid, heating is stopped, and the solution is diluted in 2000mL of deionized water, aged for 4h, and then filtered, washed until the solution is neutral, to obtain a zinc hydroxide wet gel.

[0034] The 100 g of the zinc hydroxide wet gel with a water content of 60% is added to 1000 mL of anhydrous ethanol, ultrasonic dispersion is performed until uniform, and then the mixture is placed in a single-necked flask. Then, 20 g of cystine is added and stirred uniformly. A 10% phosphoric acid ethanol solution of 1200 mL is added dropwise at a rate of 2 drops per second. The reaction is carried out at room temperature at a speed of 400 r / min for 30 min. Finally, filtration, washing and drying are performed to obtain the modified zinc phosphate.

[0035] The preparation method of the modified zinc phosphate in Example 2 comprises the following steps:

[0036] 100 g of zinc oxide is added to 1000 mL of an ammonium carbonate-ammonia complex solution to dissolve the zinc oxide, wherein the mass fraction of ammonium carbonate in the ammonium carbonate-ammonia complex solution is 25%, and the mass fraction of ammonia water is 25%, to obtain a zinc carbonate sol.

[0037] 1000 mL of the above zinc carbonate sol is placed in a 70℃ water bath, heated and stirred, until the solution is slightly turbid. The heating is stopped, and the solution is diluted in 2000 mL of deionized water. After aging for 4 h, filtration, washing until the solution is neutral, and drying are performed to obtain a zinc hydroxide wet gel.

[0038] The 100 g of the zinc hydroxide wet gel with a water content of 60% is added to 1000 mL of anhydrous ethanol, ultrasonic dispersion is performed until uniform, and then the mixture is placed in a single-necked flask. Then, 20 g of cystine is added and stirred uniformly. A 10% phosphoric acid ethanol solution of 1200 mL is added dropwise at a rate of 2 drops per second. The reaction is carried out at room temperature at a speed of 400 r / min for 30 min. Finally, filtration, washing and drying are performed to obtain the modified zinc phosphate.

[0039] The preparation method of the nano-silicon dioxide coated polyphosphate calcium in Example 3 comprises the following steps:

[0040] 100 g of calcium carbonate powder is placed in a 1000 mL beaker, 200 mL of deionized water is added, and the mixture is stirred and mixed uniformly. Then, the water bath is raised to 70℃, and 512 g of phosphoric acid is added. After the reaction for 30 min, the reaction endpoint is controlled to be pH 3.2. After concentration, crystallization and drying, the mixture is placed in a muffle furnace for calcination. The calcination temperature is 800℃, and the time is 5 h to obtain polyphosphate calcium.

[0041] 100 g of the above polyphosphate calcium is dispersed in 100 mL of 0.1M dilute hydrochloric acid, stirred for 30 min, centrifuged and washed with deionized water until neutral. Then, the mixture is vacuum dried at 60℃ to obtain activated polyphosphate calcium.

[0042] 100g of the activated polymeric calcium phosphate above was dispersed in 2000ml of a 10% mass fraction hydrolysis solution of γ-aminopropyl triethoxysilane, stirred and reacted at 60°C for 2h, centrifuged, washed with ethanol 3 times, and vacuum dried at 60°C to obtain a coupling agent modified polymeric calcium phosphate;

[0043] 100g of the modified coupling agent modified polymeric calcium phosphate above was dispersed in 4000ml of an ethanol-water mixture (volume ratio 4:1), ultrasonically treated for 30min, 60ml of tetraethyl orthosilicate was added, ammonia water was added dropwise to adjust the pH to 9-10, the temperature was raised to 40°C, magnetic stirring was performed for 6h, 20ml of glacial acetic acid was added to neutralize to pH=7, the growth of nanosilica was stopped, centrifugation was performed at 4000rpm for 10min, washing was performed with ethanol and water alternately 3 times, and vacuum drying was performed at 60°C for 24h to obtain nanosilica coated polymeric calcium phosphate.

[0044] Example 4 An inorganic modified super-long salt spray resistant water-based paint was prepared by the following method:

[0045] 60 parts by mass of a water-based acrylic resin, 0.3 parts by mass of isothiazolinone, 0.3 parts by mass of an organic non-ionic wetting agent, 0.6 parts by mass of an anionic surfactant, 0.2 parts by mass of an organic silicon defoaming agent, 0.8 parts by mass of 2-amino-2-methyl-1-propanol, 10 parts by mass of the nanosilica coated polymeric calcium phosphate prepared in Example 1, 1 part by mass of the modified zinc phosphate prepared in Example 3, 9 parts by mass of jian mica powder, 3 parts by mass of diethylene glycol methyl ether, 20 parts by mass of water, and 0.8 parts by mass of a polyurethane thickener were added to a basket sand mill and mixed and ground, the maximum particle size was ≤20μm, and an inorganic modified super-long salt spray resistant water-based paint was obtained.

[0046] Example 5 An inorganic modified super-long salt spray resistant water-based paint was prepared by the following method:

[0047] 60 parts by mass of a water-based acrylic resin, 0.3 parts by mass of isothiazolinone, 0.3 parts by mass of an organic non-ionic wetting agent, 0.6 parts by mass of an anionic surfactant, 0.2 parts by mass of an organic silicon defoaming agent, 0.8 parts by mass of 2-amino-2-methyl-1-propanol, 10 parts by mass of the nanosilica coated polymeric calcium phosphate prepared in Example 2, 1 part by mass of the modified zinc phosphate prepared in Example 3, 9 parts by mass of jian mica powder, 3 parts by mass of diethylene glycol methyl ether, 20 parts by mass of water, and 0.8 parts by mass of a polyurethane thickener were added to a basket sand mill and mixed and ground, the maximum particle size was ≤20μm, and an inorganic modified super-long salt spray resistant water-based paint was obtained.

[0048] Example 6 An inorganic modified super-long salt spray resistant water-based paint was prepared by the following method:

[0049] An inorganic modified super-long salt spray resistant waterborne paint was prepared by the following method:

[0050] Example 7 An inorganic modified super-long salt spray resistant waterborne paint was prepared by the following method:

[0051] An inorganic modified super-long salt spray resistant waterborne paint was prepared by the following method:

[0052] Comparative Example 1 Compared with Example 4, Comparative Example 1 only replaced the modified zinc phosphate prepared in Example 1 added in Example 4 with unmodified zinc phosphate in the same amount, and the other components and preparation method were completely consistent with Example 4.

[0053] Comparative Example 2 Compared with Example 4, Comparative Example 2 only replaced the modified zinc phosphate prepared in Example 1 added in Example 4 with the nano-silica coated polyphosphoric acid calcium prepared in Example 3 in the same amount, and the other components and preparation method were completely consistent with Example 4.

[0054] Comparative Example 3 Compared with Example 4, Comparative Example 3 only replaced the nano-silica coated polyphosphoric acid calcium prepared in Example 3 added in Example 4 with the modified zinc phosphate prepared in Example 1 in the same amount, and the other components and preparation method were completely consistent with Example 4.

[0055] Comparative Example 4 Compared with Example 4, Comparative Example 4 only replaced the nano-silica coated polyphosphoric acid calcium prepared in Example 3 added in Example 4 with the uncoated nano-silica prepared in Example 3 in the same amount, and the other components and preparation method were completely consistent with Example 4.

[0056] Comparative Example 5 An inorganic modified super-long salt spray resistant waterborne coating was prepared by the following method:

[0057] 60 parts by mass of waterborne acrylic resin, 0.3 parts by mass of isothiazolinone, 0.3 parts by mass of organic non-ionic wetting agent, 0.6 parts by mass of anionic surfactant, 0.2 parts by mass of silicone defoamer, 0.8 parts by mass of 2-amino-2-methyl-1-propanol, 10 parts by mass of polymerized calcium phosphate without coated nano-silica in Example 1, 1.6 parts by mass of nano-silica, 1 part by mass of modified zinc phosphate prepared in Example 3, 9 parts by mass of sericite powder, 3 parts by mass of diethylene glycol methyl ether, 20 parts by mass of water, and 0.8 parts by mass of polyurethane thickener were added into a basket sand mill for mixing and grinding until the maximum particle size was ≤20 μm, to obtain an inorganic modified super-long salt spray resistant waterborne coating.

[0058] Performance detection

[0059] Salt spray resistance: The coating obtained in Examples 4-7 and Comparative Examples 1-5 was coated on a test steel plate, and placed in an environment with a temperature of (25±5) °C and a humidity of 80%±5% for self-drying for 7 days, with a film thickness of about 60 μm. A cross line was drawn on the coating film using a cutter, and the line was drawn through to the steel plate to expose the surface, with the distance between the line and any edge of the steel plate being greater than 20 mm. The edges were sealed with wax, and the salt spray resistance test was performed in a 35 °C salt spray chamber. During the salt spray test, the corrosion of the sample plate was observed every 24 h. If rust spots appeared on the plate surface or the corrosion at the drawn line was more than 2 cm wide, the test was terminated and the sample was determined to be unqualified. The test results are shown in Table 1.

[0060] Hardness: The hardness of the coating obtained in Examples 4-7 and Comparative Examples 1-5 was tested according to GB / T 6739-1996 “Pencil hardness test method for coating film”. The coating was coated on a test steel plate, and placed in an environment with a temperature of (25±5) °C and a humidity of 80%±5% for self-drying for 7 days, with a film thickness of about 60 μm. A Chinese pencil was selected, and the pencil was held at an angle of 45° with the coating film surface, and was pushed forward at a speed of 1 cm / s until the pencil broke. Five lines were drawn on the coating film using the pencil of each hardness level. If two or more lines were damaged, a softer pencil was used until a pencil was found that did not damage the coating film. The hardness of the pencil represented the pencil hardness of the coating film. The hardness levels were 9H, 8H, 7H, 6H, 5H, 4H, 3H, 2H, H, F, HB, B, 2B, 3B, 4B, 5B, 6B, with 9H being the hardest and 6B being the softest. The test results are shown in Table 1.

[0061] Water resistance: The paint obtained in Examples 4-7 and Comparative Examples 1-5 was coated on a test steel plate, and left to dry for 7 days in an environment with a temperature of (25±5) °C and a humidity of 80%±5%, with a film thickness of about 60 μm. The prepared sample was vertically placed in a test water tank, with half immersed in water and half exposed to air. The surface of the half immersed in water was observed every 1 day, and if blistering occurred, the sample was deemed to be unqualified. The test results are shown in Table 1.

[0062] Adhesion: The adhesion of the coating was tested according to GB / T 9286-1998 “Paints and varnishes - Cross-hatch adhesion test”. The paint obtained in Examples 4-7 and Comparative Examples 1-5 was coated on a test steel plate, and left to dry for 7 days in an environment with a temperature of (25±5) °C and a humidity of 80%±5%, with a film thickness of about 60 μm. A cross-hatch method was used to draw a hundred squares on the sample, and the knife should penetrate the coating to the substrate. The adhesive tape was attached to the center of the sample, and the tape was quickly and continuously pulled off to evaluate the adhesion according to the condition of the coating film. The adhesion was graded from 0 to 5, and the lower the grade, the better the adhesion of the coating to the substrate. The test results are shown in Table 1.

[0063] Ion release: The paint obtained in Examples 4-7 and Comparative Examples 1-5 was coated on a test steel plate, and left to dry for 7 days in an environment with a temperature of (25±5) °C and a humidity of 80%±5%, with a film thickness of about 60 μm. The steel plate was immersed in a pH=8.5 buffer solution for 7 days, and the concentrations of calcium ions and zinc ions were determined after filtration. The test results are shown in Table 1.

[0064] Table 1: Performance test data of the paint of Examples 4-7 and Comparative Examples 1-5

[0065]

[0066] As shown in Table 1, the inorganic modified super-long salt spray resistant water-based paint prepared in Examples 4-7 of the present application is coated on the surface of a steel plate, and the obtained coating has super-long salt spray resistance, high adhesion and low calcium ion and zinc ion elution amount, and also improves the hardness and water resistance of the coating. In Comparative Example 1, the zinc phosphate added is not modified by cystine, and the obtained water-based paint has decreased salt spray resistance. In Comparative Example 2, only nano-silica coated polymeric calcium phosphate is added as a rust-preventing pigment, and the obtained water-based paint has decreased hardness and salt spray resistance. In Comparative Example 3, only modified zinc phosphate is added as a rust-preventing pigment, and the obtained water-based paint has high zinc ion elution amount, and decreased adhesion and water resistance. In Comparative Example 4, polymeric calcium phosphate is not coated with nano-silica, and the obtained water-based paint has decreased water resistance, adhesion and salt spray resistance, and high calcium ion elution amount. In Comparative Example 5, nano-silica is added, but the nano-silica is not coated on the polymeric calcium phosphate, and the obtained water-based paint has high calcium ion elution amount, and decreased salt spray resistance. The cystine modified zinc phosphate on the surface can improve the salt spray resistance of the zinc phosphate, and the modified zinc phosphate and the nano-silica coated polymeric calcium phosphate have a synergistic effect of improving the salt spray resistance, and reduce the amount of zinc phosphate, thereby reducing the zinc ion elution amount and cost. Furthermore, the polymeric calcium phosphate is coated with nano-silica, which on one hand improves the water resistance and adhesion of the coating, and on the other hand reduces the calcium ion elution amount.

[0067] The above detailed one embodiment of the present application, but the content described is only the preferred embodiment of the present application, and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made in the scope of the present application should still belong to the scope of the present application.

Claims

1. An inorganic modified super long salt spray resistant water-based coating, characterized in that: At least include the following raw materials by mass: 60-70 parts of water-based acrylic resin, 0.1-0.5 parts of fungicide, 0.2-0.4 parts of wetting agent, 0.5-1 parts of dispersant, 0.1-0.3 parts of defoaming agent, 0.5-1 parts of pH regulator, 8-12 parts of nano-silica-coated polycalcium phosphate, 0.5-2 parts of modified zinc phosphate, 8-10 parts of jane mica powder, 2-4 parts of film-forming aid, 10-20 parts of water, and 0.5-1 parts of polyurethane thickener.

2. The inorganic modified super-long salt spray resistant water-based coating according to claim 1, characterized in that: The preparation method of the modified zinc phosphate comprises the following steps: Adding zinc oxide to an ammonium carbonate-ammonia aqueous solution to obtain a zinc carbonate sol; The zinc carbonate sol is heated, added to deionized water for dilution, aged, filtered, and washed to obtain a zinc hydroxide wet gel; The zinc hydroxide wet gel and cystine are added to anhydrous ethanol, and then a phosphoric acid ethanol solution is added, reacted, filtered, washed, and dried to obtain modified zinc phosphate.

3. The inorganic modified super-long salt spray resistant water-based coating according to claim 2, characterized in that: The mass ratio of the zinc hydroxide wet gel, the cystine and the ethanolic phosphoric acid solution is 10:2-3:100-120, and the water content of the zinc hydroxide wet gel is 50-60%.

4. The inorganic modified super-long salt spray resistant water-based coating according to claim 2, characterized in that: The mass ratio of the zinc oxide to the ammonium carbonate-ammonia water composite solution is 10:100-120, and the pH value of the ammonium carbonate-ammonia water composite solution is 9-10.

5. The inorganic modified super-long salt spray resistant water-based coating according to claim 2, characterized in that: The mass fraction of ammonium carbonate in the ammonium carbonate-ammonia water composite solution is 20-25%, the mass fraction of ammonia water is 25-28%, and the mass fraction of phosphoric acid in the phosphoric acid ethanol solution is 10-15%.

6. The inorganic modified super-long salt spray resistant water-based coating according to claim 1, characterized in that: The preparation method of the nano-silica-coated polycalcium phosphate comprises the following steps: Calcium carbonate is dispersed in deionized water, phosphoric acid is added for reaction, and polycalcium phosphate is obtained after concentration, crystallization, drying and calcination. Dispersing the polycalcium phosphate in dilute hydrochloric acid, stirring, washing, and drying to obtain activated polycalcium phosphate; adding the activated polycalcium phosphate to a hydrolyzate of γ-aminopropyltriethoxysilane, reacting, washing, and drying to obtain coupling agent-modified polycalcium phosphate; The coupling agent-modified cystine polycalcium phosphate is dispersed in an ethanol / water solution, ethyl orthosilicate is added, ammonia water is added dropwise, the reaction is carried out, washing and drying are carried out to obtain nano-silica-coated polycalcium phosphate.

7. The inorganic modified super-long salt spray resistant water-based coating according to claim 6, characterized in that: The mass ratio of the calcium carbonate to the phosphoric acid is 1:5-6.

8. The inorganic modified super-long salt spray resistant water-based coating according to claim 6, characterized in that: The mass ratio of the activated polycalcium phosphate, the gamma-aminopropyltriethoxysilane and the ethyl orthosilicate is 100:3-8:1-3.

9. The inorganic modified super-long salt spray resistant water-based coating according to claim 1, characterized in that: The bactericide is isothiazolinone, the wetting agent is one or a mixture of an organic non-ionic wetting agent, polyacrylate aluminum salt or modified dihydroxycarboxylate compound, the dispersant is one or a mixture of an anionic surfactant, a bisamide dispersant, a paraffin dispersant or an organic metal salt dispersant, the defoamer is one of a polyether defoamer or a silicone defoamer, the pH regulator is one or a mixture of N,N-dimethylethanolamine, triethylamine, ammonia water, triethanolamine, diethylamine, diethanolamine or 2-amino-2-methyl-1-propanol, and the film-forming aid is one or a mixture of diethylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol phenyl ether or lauryl alcohol ester.

10. A method for preparing an inorganically modified ultra-long salt spray resistant water-based coating, characterized in that: The method comprises at least the following preparation steps: Add water-based acrylic resin, fungicide, wetting agent, dispersant, defoaming agent, pH regulator, nano-silica-coated polycalcium phosphate, modified zinc phosphate, jacquard mica powder, film-forming aid, water, and polyurethane thickener into a basket sand mill for mixing and grinding until the maximum particle size is ≤20 μm to obtain an inorganically modified ultra-long salt spray resistant water-based coating.

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