Micro-nano three-dimensional structure zinc phosphate pigment and synthesis method thereof

Abstract

The present invention provides a micro-nano three-dimensional structure zinc phosphate pigment and a synthesis method thereof, belonging to the technical field of anti-corrosion inorganic pigment synthesis, comprising the following steps: S1: preparing a zinc-containing solution containing a soluble zinc salt, an anionic surfactant and an alkaline regulator, wherein the pH value of the zinc-containing solution is 11-14; S2: preparing a phosphate-containing solution containing an organic solvent, phosphoric acid, a soluble phosphate and an acidic regulator, wherein the pH value of the phosphate-containing solution is 1-3; S3: spraying the phosphate-containing solution into the zinc-containing solution in an atomized state to form a mixed solution, and performing ultrasonic refinement and heating and heat preservation on the mixed solution, wherein the heating temperature is to 25°C and the temperature is kept for 0.1-24h; S4: filtering the precipitate in the mixed solution and drying the precipitate to obtain a micro-nano three-dimensional structure zinc phosphate pigment, which can synthesize and prepare a micro-nano three-dimensional structure zinc phosphate pigment with a small size, a large specific surface area and a stable three-dimensional spatial structure.

Description

Technical Field

[0001] The invention belongs to the technical field of anticorrosive inorganic pigment synthesis, and particularly relates to a micro-nano three-dimensional structure zinc phosphate pigment and a synthesis method thereof. Background Art

[0002] Zinc phosphate is an inorganic compound in the form of colorless rhombic crystals or white microcrystalline powder. As an excellent anti-rust pigment, it is widely used in anti-corrosion coatings, water-based coatings, architectural coatings and other coating fields. Currently, zinc phosphate pigments prepared by existing technologies on the market have problems such as coarse particle size, small specific surface area and insufficient activity. In addition, zinc phosphate pigments on the market are all two-dimensional planar structures. These problems limit the application of zinc phosphate pigments in organic coatings. Specifically, the coarse particle size makes it difficult for zinc phosphate pigments to be evenly dispersed in relatively delicate organic coating systems, the small specific surface area makes the effective contact area for zinc phosphate pigments to react chemically with the surrounding environment (such as other components in the coating, the surface of the metal substrate, etc.) small, and the insufficient activity makes the ability of zinc phosphate pigments to react with the metal substrate in organic coatings weak. It cannot fully utilize its own chemical properties to effectively react chemically with metal elements such as Fe, Al and Mg on the surface of the substrate. For example, the process of forming a passivation film such as chemically stable phosphate is not smooth enough; zinc phosphate pigments with two-dimensional planar structures are difficult to match the maze effect formed by three-dimensional structured pigments, thereby playing a significant blocking role in the penetration of corrosive ions; and the two-dimensional planar structure of zinc phosphate pigments makes it difficult for them to fully conform to the complex shapes of the metal substrate such as microscopic unevenness and holes when they come into contact with the metal substrate in organic coatings, and a spatial hindrance effect will also be produced during the film-forming process of the organic coating. All of the above problems lead to the problem that zinc phosphate pigments have obviously insufficient corrosion protection ability when used in organic coatings. Summary of the invention

[0003] The purpose of the present invention is to provide a micro-nano three-dimensional structured zinc phosphate pigment and a synthesis method thereof, by adding anionic surfactants, complexing agents and a zinc-containing solution with a pH adjustment value and adjusting the conditions of the synthesis steps to prepare a micro-nano three-dimensional structured zinc phosphate pigment with a small size, a large specific surface area and a stable three-dimensional spatial structure, thereby improving its corrosion protection effect in organic coatings.

[0004] To achieve the above objectives, the present technical solution provides a method for synthesizing a micro-nano three-dimensional structured zinc phosphate pigment, comprising the following steps:

[0005] S1: preparing a zinc-containing solution containing deionized water, anionic surfactant, soluble zinc salt and alkaline regulator, wherein the pH value of the zinc-containing solution is 11-14;

[0006] S2: preparing a phosphate solution containing deionized water, an organic solvent, phosphoric acid, a soluble phosphate and an acidic regulator, wherein the pH value of the phosphate solution is 1-3;

[0007] S3: spraying the phosphate-containing solution into the zinc-containing solution in an atomized state to form a mixed solution, and performing ultrasonic refinement and heating and heat preservation on the mixed solution, wherein the heating temperature is 25° C. and the temperature is kept for 0.1 to 24 hours;

[0008] S4: filtering the precipitate in the mixed solution and drying the precipitate to obtain a micro-nano three-dimensional structured zinc phosphate pigment.

[0009] In a second aspect, the present invention provides a micro-nano three-dimensional structured zinc phosphate pigment, which is synthesized according to the synthesis method of the micro-nano three-dimensional structured zinc phosphate pigment of the first aspect.

[0010] Compared with the prior art, the present technical solution has the following characteristics and beneficial effects: the micro-nano three-dimensional structured zinc phosphate pigment and its synthesis and application method provided in the present solution can synthesize a zinc phosphate pigment with a micro-nano three-dimensional structure. The zinc phosphate pigment has a small grain size, a large specific surface area, and a stable three-dimensional spatial structure. This three-dimensional structural advantage significantly improves the performance of the pigment in anti-corrosion applications and reduces the risk of metal corrosion.

[0011] Micro-nano three-dimensional structure zinc phosphate pigments have unique three-dimensional structures such as three-dimensional flower shapes, spheres or cactus shapes. Compared with traditional two-dimensional structures, they can cover the metal surface in all directions, forming a maze effect, and have a good physical shielding effect on the penetration of corrosive ions, leaving no blind spots for protection, greatly improving the anti-corrosion performance of organic coatings and extending the service life of metal products.

[0012] Micro-nano three-dimensional structured zinc phosphate pigments have a larger specific surface area, so that when micro-nano three-dimensional structured zinc phosphate pigments are used in organic coatings, they can fully absorb and fix anti-rust components to form a denser protective layer. The three-dimensional structure is conducive to the uniform dispersion of the pigment and avoids agglomeration, ensuring the stability of the coating performance, effectively resisting the erosion of corrosive media, and ensuring the integrity of metal parts. Its three-dimensional shape helps to build a solid physical barrier in organic coatings, which can not only effectively block the penetration of corrosive factors such as moisture and oxygen, but also form a continuous and complete protective film on the metal surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a scanning electron microscope image of the micro-nano three-dimensional flower-like structure zinc phosphate pigment prepared according to Example 1 of the present invention.

[0014] Figure 2 This is the XRD spectrum of the micro-nano three-dimensional flower-like structure zinc phosphate pigment prepared according to Example 1 of the present invention.

[0015] Figure 3 This is a scanning electron microscope image of the micro-nano three-dimensional spherical structure zinc phosphate pigment prepared according to Example 2 of the present invention.

[0016] Figure 4 This is a scanning electron microscope image of the micro-nano three-dimensional cactus-shaped zinc phosphate pigment prepared according to Example 3 of the present invention.

[0017] Figure 5 This is a scanning electron microscope image of the micro-nano three-dimensional rosette-shaped zinc phosphate pigment prepared according to Example 4 of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the accompanying drawings in 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 belong to the scope of protection of the present invention.

[0019] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0020] In a first aspect, the present invention provides a method for synthesizing a micro-nano three-dimensional structured zinc phosphate pigment, comprising the following steps:

[0021] S1: preparing a zinc-containing solution containing deionized water, a soluble zinc salt, an anionic surfactant and an alkaline regulator, wherein the pH value of the zinc-containing solution is 11-14;

[0022] S2: preparing a phosphate solution containing deionized water, an organic solvent, phosphoric acid, a soluble phosphate and an acidic regulator, wherein the pH value of the phosphate solution is 1-3;

[0023] S3: spraying the phosphate-containing solution into the zinc-containing solution in an atomized state to form a mixed solution, and performing ultrasonic refinement and heating and heat preservation on the mixed solution, wherein the heating temperature is 25° C. and the temperature is kept for 0.1 to 24 hours;

[0024] S4: filtering the precipitate in the mixed solution and drying the precipitate to obtain a micro-nano three-dimensional structured zinc phosphate pigment.

[0025] The synthesis method of the micro-nano three-dimensional structured zinc phosphate pigment provided in the scheme adds anionic surfactant to the zinc-containing solution and adjusts the pH value of the zinc-containing solution to be strongly alkaline by pH value, so that when the zinc-containing solution and the phosphate-containing solution are mixed, the growth of crystals can be effectively inhibited, thereby forming zinc phosphate nanocrystals with smaller sizes, and the phosphate-containing solution contains an organic solvent that can also dilute the concentration of phosphate ions to slow down the reaction rate between phosphate ions and zinc ions, and reacts to form a micro-nano three-dimensional structured zinc phosphate pigment under a suitable reaction environment, thereby increasing the specific surface area of ​​the micro-nano three-dimensional structured zinc phosphate pigment.

[0026] Notes on step S1:

[0027] The soluble zinc salt contained in the zinc-containing solution provided in this solution is selected from one or a mixture of inorganic soluble zinc salts and organic soluble zinc salts. In some organic coating applications that require high water resistance of the pigment, inorganic soluble zinc salts may be preferred because they may give the pigment better water resistance after forming zinc phosphate pigments; and in some cases where the compatibility of the pigment and the coating system is outstanding, organic soluble zinc salts may provide better compatibility, and in this case, organic soluble zinc salts can be used alone or in combination.

[0028] In some embodiments, when the soluble zinc salt contained in the zinc-containing solution is selected as an inorganic soluble zinc salt, the inorganic soluble zinc salt is selected from zinc chloride, zinc sulfate, zinc nitrate, zinc bromide, zinc perchlorate, or a combination of several thereof under compatible conditions. When an inorganic soluble zinc salt is selected, in the process of preparing zinc phosphate pigment, even if the reaction conditions fluctuate to a certain extent, zinc ions can be provided stably to participate in the reaction.

[0029] In other embodiments, when the soluble zinc salt contained in the zinc-containing solution is selected as an organic soluble zinc salt, the organic soluble zinc salt is selected from one of zinc acetate, zinc gluconate, zinc lactate, zinc propionate, zinc citrate, zinc formate dihydrate, zinc hexafluorosilicate, and zinc salicylate, or a combination of several of them under compatible conditions. When an organic soluble zinc salt is selected, the crystal structure of the zinc phosphate pigment can be regulated by selecting the organic soluble zinc salt during the preparation of the zinc phosphate pigment.

[0030] It should be noted that when the zinc-containing solution contains inorganic soluble zinc salt, a complexing agent is added to the zinc-containing solution; when the zinc-containing solution contains organic soluble zinc salt, no complexing agent is added to the zinc-containing solution or a small amount of complexing agent is added, wherein the complexing agent is alkaline. The use of complexing agents can maintain the ZnO2 in the zinc-containing solution. 2- It exists stably and effectively inhibits the agglomeration of nano zinc phosphate crystals during their growth, making it easier to prepare micro-nano zinc phosphate pigments with three-dimensional structures.

[0031] Specifically, when the zinc-containing solution contains an inorganic soluble zinc salt, due to the zinc ion (Zn 2+ ) will react with the hydroxide ions in the zinc solution, and some zinc ions will gradually convert into zincate ions (ZnO2 2- ) exists in the form of, however, ZnO2 2- It is not naturally stable in solution, and it is easily affected by many factors and changes, such as reacting with other ions in the solution or decomposing itself. At this time, the addition of complexing agent is like giving ZnO2 2- Provides a "stabilizer" that allows the complexing agent to react with ZnO2 2- Forming a specific complex structure, it effectively "wraps" it, making ZnO2 2- It can maintain a relatively stable state in the solution. When the zinc-containing solution contains inorganic soluble zinc salts, due to the interaction between various ions and the characteristics of crystal growth, nano zinc phosphate crystals are easy to aggregate together to form larger agglomerates, and the added alkaline complexing agent can effectively inhibit the occurrence of this agglomeration phenomenon: on the one hand, the complexing agent forms a complex with zinc ions and other related ions, changing the existence state and distribution of these ions in the solution, which makes the ion environment around each crystal nucleus relatively more uniform and stable in the early stage of crystal growth, reducing the possibility of mutual attraction and aggregation between crystal nuclei due to excessive local ion concentration. On the other hand, the complexing agent will continue to play a role during the crystal growth process. It adheres to the surface of the growing zinc phosphate crystals to form a layer of structure similar to a "protective film". This "protective film" prevents direct contact and mutual adhesion between different crystals, allowing each crystal to grow in a relatively independent space, making it easier to form a micro-nano zinc phosphate pigment with a three-dimensional structure.

[0032] When the zinc-containing solution contains organic-soluble zinc salts, the organic-soluble zinc salts themselves often carry various organic groups. These organic groups will produce specific interactions with zinc ions in the solution, so that the existence state and reaction activity of zinc ions have been regulated to a certain extent. When a small amount of chelating agent is added, it can cooperate with the organic groups carried by the organic-soluble zinc salts to further optimize the existence state of zinc ions in the solution. At the same time, the presence of a small amount of chelating agent can also inhibit the agglomeration phenomenon of nano-zinc phosphate crystals during growth to a certain extent.

[0033] In an embodiment of the present scheme, the complexing agent is one or more of sodium acetate, sodium gluconate, sodium lactate, sodium citrate, sodium salicylate, sodium propionate, and sodium tartrate.

[0034] The anionic surfactant selected in this scheme includes one or more of sodium dodecylbenzene sulfonate, sodium oleate, sodium laurate, and sodium dodecyl sulfate. It should be emphasized that the aqueous solution of the anionic surfactant is a weakly alkaline or neutral solution, which can effectively inhibit the growth of crystals, thereby forming zinc phosphate nanocrystals with smaller sizes, and effectively inhibit the occurrence of nanocrystal agglomeration.

[0035] Taking sodium dodecylbenzene sulfonate as an example, sodium dodecylbenzene sulfonate can be quickly dispersed and adsorbed on the surface of the newly formed zinc phosphate crystal nucleus during the mixing process of the zinc-containing solution and the phosphate-containing solution. The sulfonic acid group is negatively charged and will produce electrostatic attraction with the cations in the solution, while the hydrophobic dodecylbenzene group tends to move away from the aqueous solution and toward the inside of the crystal nucleus or other hydrophobic areas. This adsorption not only changes the surface properties of the crystal nucleus, but also affects the ion distribution and diffusion around the crystal nucleus to a certain extent, laying the foundation for the subsequent inhibition of crystal growth.

[0036] Taking sodium oleate as an example, during the mixing process of zinc-containing solution and phosphate-containing solution, sodium oleate will interact with the cations in the solution through ion exchange or electrostatic attraction through its sodium carboxylate group, and at the same time, use the hydrophobicity of the oleic acid group to form a protective film-like adsorption layer on the surface of the crystal nucleus. This adsorption layer can prevent other ions (such as zinc ions and phosphate ions) from accumulating on the crystal nucleus too quickly, thereby regulating the growth rate of the crystal and helping to form smaller zinc phosphate nanocrystals.

[0037] Taking sodium laurate as an example, during the mixing process of zinc-containing solution and phosphate-containing solution, sodium laurate can diffuse rapidly in the solution and adsorb to the surface of the crystal nucleus. Its hydrophilic groups form hydrogen bonds and other interactions with water molecules in the solution to maintain its own stable existence in the solution; while the hydrophobic lauryl group fits tightly to the surface of the crystal nucleus, changing the surface energy state of the crystal nucleus. This change makes it more difficult for the crystal nucleus to absorb surrounding ions indefinitely to expand its own size during the subsequent growth process, thereby effectively inhibiting the growth of the crystal and promoting the formation of smaller zinc phosphate nanocrystals.

[0038] Taking sodium dodecyl sulfate as an example, during the mixing process of zinc-containing solution and phosphate-containing solution, sodium dodecyl sulfate will interact with cations in the solution through sulfate groups, and at the same time, the hydrophobic dodecyl groups will be covered on the surface of the crystal nucleus. This adsorption method changes the ion environment around the crystal nucleus, and the adsorption and diffusion process of ions on the surface of the crystal nucleus is disturbed, thereby limiting the growth rate of the crystal, which helps to achieve the goal of forming zinc phosphate nanocrystals with smaller sizes, and can effectively inhibit the occurrence of nanocrystal agglomeration.

[0039] In addition, the main purpose of adding the alkaline regulator to the zinc-containing solution of the present invention is to control the pH value of the zinc-containing solution. The advantage of adjusting the pH value of the zinc-containing solution to between 11 and 14 is that it can promote the formation of zinc ions Zn 2+ Converted into zincate ion ZnO2 2- , effectively inhibiting the precipitation of zinc ions.

[0040] In some embodiments, the alkaline regulator is selected from one or more of acetic acid, citric acid, tartaric acid, malic acid, succinic acid, lactic acid, potassium hydroxide, sodium hydroxide, and ammonia water.

[0041] In addition, the zinc-containing solution in step S1 of this solution is placed in an auxiliary device with ultrasonic oscillation and microwave heating functions, and optionally, the ultrasonic oscillation frequency is 20kHz to 130kHz; the microwave radiation heater power is 100W to 2000W. The temperature of the zinc-containing solution is controlled to be 25°C to 90°C to avoid precipitation of zinc ions due to excessively high temperature.

[0042] In some embodiments, the mass ratio of the soluble zinc salt, the anionic surfactant and the complexing agent is set between 3:1:1 and 5:1:1, and the content of the pH adjuster is to adjust the pH value to a specified range. This has the advantage of promoting the dissolution of the zinc salt and Zn 2+ Ions converted to ZnO2 2- ions and exists stably in the solution. 2- Ion concentration to prevent zinc phosphate crystals from agglomerating after they are formed.

[0043] In addition, in step S1, in each liter of deionized water, the soluble zinc salt is 5g~30g, and the anionic surfactant is 1g~10g or 5mL~20mL, the complexing agent is 1g~10g, and the alkaline pH adjuster is 1g~10g or 1mL~20mL.

[0044] Notes on step S2:

[0045] Different from the conventional solution that only contains soluble phosphate in the phosphate-containing solution, the phosphate-containing solution of the present solution contains phosphoric acid and soluble phosphate. Phosphoric acid will be ionized in the phosphate-containing solution to provide phosphate ions and generate hydrogen ions at the same time.

[0046] Specifically, the phosphoric acid in the phosphate-containing solution of the present embodiment is orthophosphoric acid. In some embodiments, the phosphate-containing solution may further contain metaphosphoric acid in addition to orthophosphoric acid. Orthophosphoric acid is selected in the phosphate-containing solution because it can stably provide phosphate ions (PO4). 3- , and the hydrogen ions H +It has an important influence on the pH value of the solution and the overall ion environment. Metaphosphoric acid will undergo polymerization in the solution to form metaphosphoric acid molecular chains with different polymerization degrees. These molecular chains will decompose and release phosphate ions under certain conditions. The presence of metaphosphoric acid enriches the supply of phosphate ions in phosphate-containing solutions. In the process of preparing zinc phosphate pigments, it works synergistically with orthophosphoric acid.

[0047] It should be emphasized that the pH value of the phosphate solution in this scheme is controlled at 1-3. The advantage of such control is that it effectively promotes the phosphate ion (PO4) 3- and zincate ions ZnO2 in zinc-containing solutions 2- The reaction generates zinc phosphate precipitation; at the same time, a large amount of heat is released during the acid-base neutralization reaction. This energy fluctuation provides more power and opportunities for the nucleation of zinc phosphate crystals. Because the nucleation process needs to overcome certain energy barriers, and the release of heat reduces this energy barrier, more areas have the conditions for forming crystal nuclei, thereby significantly increasing the number of zinc phosphate crystal nucleation sites; and for the zinc phosphate nuclei that have been formed, the acidic conditions regulate the concentration and diffusion rate of the surrounding ions, limiting more ions from quickly gathering on the nuclei to make them grow, inhibiting the growth of the nuclei to form micro-nano zinc phosphate crystals.

[0048] In some embodiments, the acidic regulator is selected from one or more of hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, sodium dihydrogen phosphate, and potassium dihydrogen phosphate.

[0049] The purpose of the phosphate-containing solution in this scheme containing an organic solvent is that the organic solvent can effectively dilute the phosphate ions (PO4) in the phosphate-containing solution. 3- concentration, slowing down the phosphate ion (PO4) 3- With zinc ion Zn 2+ The reaction rate is increased, and it is beneficial for the zinc phosphate grains to grow along the (220) and (241) crystal planes, presenting a three-dimensional structure of zinc phosphate pigment formed by lamellar stacking.

[0050] In some embodiments, the organic solvent is one or more of ethanol, polyethylene glycol, glycerol, and ethyl acetate.

[0051] The soluble phosphate in the phosphate-containing solution of the present embodiment is one of sodium phosphate, ammonium phosphate, potassium phosphate, sodium hydrogen phosphate, ammonium hydrogen phosphate, potassium hydrogen phosphate, sodium dihydrogen phosphate, ammonium dihydrogen phosphate, potassium dihydrogen phosphate, or a combination of several of them under compatible conditions.

[0052] In addition, the phosphate-containing solution in step S3 of this solution is placed in a magnetically stirred water bath. Optionally, the stirring speed of the magnetically stirred water bath is 50 r·min -1 Up to 1000 r·min-1 , the heating power is 100W to 2000W, and the temperature of the phosphate-containing solution is controlled to be 25℃~90℃.

[0053] In some embodiments, the mass ratio of phosphoric acid, soluble phosphate, and organic solvent is set between 3:1:1 and 7.5:1.5:1. The content of pH adjuster is to adjust the pH value to a specified range. The function is to increase the concentration of phosphate in the solution and promote the reaction of phosphate with Zn 2+ The reaction rate between ions; reduce the pH value of the phosphate solution, promote the generation of heat during the reaction, and provide energy for the nucleation of zinc phosphate grains.

[0054] In addition, in step S2, in each liter of deionized water, the phosphoric acid is 0.01L~0.1L, and the soluble phosphate is 5g~30g, the organic solvent is 5mL~20mL, and the acidic pH value adjuster is 1g~20g or 1mL~20m.

[0055] Notes on step S3:

[0056] The phosphate-containing solution is sprayed into the zinc-containing solution in an atomized state by using an air compressor spray device to form a mixed solution, and the mixed solution is ultrasonically refined and heated and kept warm by using an ultrasonic oscillation and microwave heating auxiliary device, wherein the heating temperature is 25°C and kept warm for 0.1~24h. The advantage of controlling a longer insulation time in this scheme is that it can effectively promote the volatilization of organic acids or ammonium ions in the mixed solution and improve the purity of zinc phosphate crystals in the precipitate.

[0057] Notes on step S4:

[0058] The precipitate in the mixed solution is filtered by a vacuum filtration device, and the precipitate is transferred to a drying box for drying to obtain a micro-nano three-dimensional structured zinc phosphate pigment, wherein the drying temperature is 50° C. to 200° C.

[0059] In the second aspect, the present invention provides a micro-nano three-dimensional structured zinc phosphate pigment, which is synthesized according to the synthesis method of the micro-nano three-dimensional structured zinc phosphate pigment mentioned in the first aspect. The micro-nano three-dimensional structured zinc phosphate pigment synthesized in the present invention has a three-dimensional spatial structure and a specific surface area of ​​20 m 2 ·g -1 ~ 198 m 2 ·g -1 The length and width dimensions are 0.1μm ~ 5.0μm, and the thickness dimensions are 10 nm ~ 200nm.

[0060] It should be noted that the thickness of the two-dimensional flaky zinc phosphate pigment on the market is basically above 100 nm, and the size of the granular zinc phosphate is above 100 nm.

[0061] In some embodiments, the three-dimensional structure is a three-dimensional flower-like structure, a three-dimensional spherical structure, or a three-dimensional cactus-like structure.

[0062] In order to verify the effectiveness of the synthesis method of the micro-nano three-dimensional structured zinc phosphate pigment of the present scheme, the present application team designed the following embodiments to provide micro-nano three-dimensional structured zinc phosphate pigments of different forms.

[0063] Embodiment 1:

[0064] S1. Take a clean beaker with a capacity of 10L, add 1L of deionized water into the beaker, and then add 20g of zinc nitrate, 10mL of polyethylene glycol, 5g of sodium acetate, and 15mL of acetic acid in sequence, which are recorded as zinc-containing solution. Use ultrasonic oscillation and microwave heating auxiliary devices to ultrasonically refine and heat the zinc-containing solution and maintain the temperature at 55°C.

[0065] S2. Take a clean beaker with a capacity of 10L, add 1L of deionized water to the beaker, and then add 0.5L of phosphoric acid, 15g of sodium phosphate, 30mL of ethanol, and 5g of sodium hydroxide in sequence, which is recorded as the phosphate solution. Use a magnetic stirring water bath to heat the phosphate solution, maintain the temperature at 55℃, and stir at a speed of 500 r·min -1 .

[0066] S3. Use an air compressor spray device to atomize the phosphate solution and spray it into the zinc solution to form a mixed solution. Use an ultrasonic oscillation and microwave heating auxiliary device to ultrasonically refine and heat the mixed solution and maintain the temperature at 55°C for 1 hour.

[0067] S4. Filter the precipitate in the mixed solution using a vacuum filtration device, and dry the precipitate in a drying oven, wherein the temperature of the drying oven is set to 100°C.

[0068] In summary, Example 1 of the present invention uses a method assisted by ultrasonic vibration and microwave heating to synthesize a zinc phosphate pigment having a micro-nano three-dimensional flower-like structure. The scanning electron microscope image of the zinc phosphate pigment having a micro-nano three-dimensional flower-like structure is as follows: Figure 1 As shown in Figure 2, the XRD spectrum of the micro-nano three-dimensional flower-like structure zinc phosphate pigment is as follows: Figure 2 As shown, it can be seen that the flower-like zinc phosphate pigment has a small grain size, a large specific surface area, and a stable three-dimensional spatial structure. It has a good physical barrier effect on corrosive ions and has high chemical activity. It can effectively passivate the base metal, thereby significantly improving the corrosion protection effect of the organic coating.

[0069] Embodiment 2:

[0070] S1. Take a clean beaker with a capacity of 10L, add 1L of deionized water into the beaker, and then add 20g of zinc acetate, 15mL of polyethylene glycol, 3g of sodium acetate, and 10mL of acetic acid in sequence, which are recorded as zinc-containing solution. Use ultrasonic oscillation and microwave heating auxiliary devices to ultrasonically refine and heat the zinc-containing solution and maintain the temperature at 30°C.

[0071] S2. Take a clean beaker with a capacity of 10L, add 1L of deionized water to the beaker, then add 0.5L of phosphoric acid, 20g of sodium dihydrogen phosphate, 15mL of ethyl acetate, and 5g of sodium hydroxide in sequence, record it as the phosphate solution, and heat the phosphate solution in a magnetic stirring water bath, maintain the temperature at 30℃, and stir at a speed of 100 r·min -1 .

[0072] S3. Use an air compressor spray device to spray the phosphate solution into the zinc solution to form a mixed solution. Use an ultrasonic oscillation and microwave heating auxiliary device to ultrasonically refine and heat the mixed solution and maintain the temperature at 30°C for 1 hour.

[0073] S4. Filter the precipitate in the mixed solution using a vacuum filtration device, and dry the precipitate in a drying oven, wherein the temperature of the drying oven is set to 100°C.

[0074] In summary, the method of ultrasonic vibration and microwave heating assisted in Example 2 of the present invention can synthesize a zinc phosphate pigment with a micro-nano three-dimensional spherical structure. The scanning electron microscope image of the spherical zinc phosphate pigment is as follows: Figure 3 As shown, it can be seen that the spherical zinc phosphate pigment has a small grain size, a large specific surface area, and a stable three-dimensional spatial structure. It has a good physical barrier effect on corrosive ions and has high chemical activity. It can effectively passivate the base metal, thereby significantly improving the corrosion protection effect of the organic coating.

[0075] Example 3

[0076] S1. Take a clean beaker with a capacity of 10L, add 1L of deionized water into the beaker, and then add 20g of zinc lactate, 2g of sodium dodecylbenzenesulfonate, 3g of sodium lactate, and 20mL of lactic acid in sequence, which is recorded as the zinc-containing solution. Use ultrasonic oscillation and microwave heating auxiliary devices to ultrasonically refine and heat the zinc-containing solution and maintain the temperature at 70°C.

[0077] S2. Take a clean beaker with a capacity of 10L, add 1L of deionized water to the beaker, then add 20g of sodium dihydrogen phosphate, 20mL of ethanol, and 5g of sodium hydroxide in sequence, record it as the phosphate solution, and heat the phosphate solution in a magnetic stirring water bath, maintain the temperature at 70℃, and stir at a speed of 100 r·min -1 .

[0078] S3. Use an air compressor spray device to spray the phosphate solution into the zinc solution to form a mixed solution. Use an ultrasonic oscillation and microwave heating auxiliary device to ultrasonically refine and heat the mixed solution and maintain the temperature at 70°C for 6 hours.

[0079] S4. Filter the precipitate in the mixed solution using a vacuum filtration device, and dry the precipitate in a drying oven, wherein the temperature of the drying oven is set to 100°C.

[0080] In summary, Example 3 of the present invention uses a method assisted by ultrasonic vibration and microwave heating to synthesize a zinc phosphate pigment with a micro-nano three-dimensional cactus-shaped structure. The scanning electron microscope image of the spherical zinc phosphate pigment grains is as follows: Figure 4 As shown, it can be seen that the spherical zinc phosphate pigment has a small grain size, a large specific surface area, and a stable three-dimensional spatial structure. It has a good physical barrier effect on corrosive ions and has high chemical activity. It can effectively passivate the base metal, thereby significantly improving the corrosion protection effect of the organic coating.

[0081] Embodiment 4:

[0082] S1. Take a clean beaker with a capacity of 10L, add 1L of deionized water into the beaker, and then add 10g of zinc formate dihydrate, 10g of zinc gluconate, 5g of sodium silicate, 3g of sodium citrate, 3g of sodium tartrate, 6g of citric acid, and 6g of tartaric acid in sequence, which is recorded as zinc-containing solution. Use ultrasonic oscillation and microwave heating auxiliary devices to ultrasonically refine and heat the zinc-containing solution and maintain the temperature at 30°C.

[0083] S2. Take a clean beaker with a capacity of 10L, add 1L of deionized water to the beaker, then add 0.1L of phosphoric acid, 20g of diammonium hydrogen phosphate, 20mL of ethanol, 5mL of glycerol, 2g of sodium hydroxide, and 5mL of ammonia water in sequence, which is recorded as the phosphate solution. Heat the phosphate solution in a magnetic stirring water bath, maintain the temperature at 30℃, and stir at a speed of 100 r·min -1 .

[0084] S3. Use an air compressor spray device to atomize the phosphate solution and spray it into the zinc solution to form a mixed solution. Use an ultrasonic oscillation and microwave heating auxiliary device to ultrasonically refine and heat the mixed solution and maintain the temperature at 30°C for 12 hours.

[0085] S4. Filter the precipitate in the mixed solution using a vacuum filtration device, and dry the precipitate in a drying oven, wherein the temperature of the drying oven is set to 100°C.

[0086] In summary, Example 4 of the present invention uses a method assisted by ultrasonic vibration and microwave heating to synthesize a zinc phosphate pigment with a micro-nano three-dimensional rosette structure. The scanning electron microscope image of the zinc phosphate pigment crystal grains with the rosette structure is as follows: Figure 5 As shown, it can be seen that the rose-shaped zinc phosphate pigment has a small grain size, a large specific surface area, and a stable three-dimensional spatial structure. It has a good physical barrier effect on corrosive ions and has high chemical activity. It can effectively passivate the base metal, thereby significantly improving the corrosion protection effect of the organic coating.

[0087] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present invention.

Claims

1. A method for synthesizing a micro-nano three-dimensional structured zinc phosphate pigment, characterized in that: The following steps are involved: S1: preparing a zinc-containing solution containing deionized water, a soluble zinc salt, an anionic surfactant and an alkaline regulator, wherein the pH value of the zinc-containing solution is 11-14, wherein the soluble zinc salt contained in the zinc-containing solution is selected from one or a mixture of an inorganic soluble zinc salt and an organic soluble zinc salt; when the zinc-containing solution contains an inorganic soluble zinc salt, a complexing agent is added to the zinc-containing solution; when the zinc-containing solution contains an organic soluble zinc salt, no or a small amount of complexing agent is added to the zinc-containing solution, wherein the complexing agent is alkaline; S2: preparing a phosphate solution containing deionized water, an organic solvent, phosphoric acid, a soluble phosphate and an acidic regulator, wherein the pH value of the phosphate solution is 1-3, and the phosphoric acid in the phosphate solution is orthophosphoric acid, or a mixture of orthophosphoric acid and metaphosphoric acid; S3: spraying the phosphate-containing solution into the zinc-containing solution in an atomized state to form a mixed solution, and performing ultrasonic refinement and heating and heat preservation on the mixed solution, wherein the heating temperature is 25° C. and the temperature is kept for 0.1 to 24 hours; S4: filtering the precipitate in the mixed solution and drying the precipitate to obtain a micro-nano three-dimensional structured zinc phosphate pigment.

2. The method for synthesizing the micro-nano three-dimensional structure zinc phosphate pigment according to claim 1, characterized in that: The complexing agent is one or more of sodium acetate, sodium gluconate, sodium lactate, sodium citrate, sodium salicylate, sodium propionate and sodium tartrate.

3. The method for synthesizing the micro-nano three-dimensional structure zinc phosphate pigment according to claim 1, characterized in that: The anionic surfactant includes one or more of sodium dodecylbenzene sulfonate, sodium oleate, sodium laurate and sodium dodecyl sulfate.

4. The method for synthesizing the micro-nano three-dimensional structure zinc phosphate pigment according to claim 1, characterized in that: The organic solvent is one or more of ethanol, polyethylene glycol, glycerol and ethyl acetate.

5. The method for synthesizing the micro-nano three-dimensional structure zinc phosphate pigment according to claim 1, characterized in that: The zinc-containing solution in step S1 is placed in an auxiliary device with ultrasonic oscillation and microwave heating functions, and the temperature of the zinc-containing solution is controlled to be 25°C~90°C; the phosphate-containing solution in step S2 is placed in a magnetically stirred water bath, and the temperature of the phosphate-containing solution is controlled to be 25°C~90°C; the mixed solution in step S3 is placed in an auxiliary device with ultrasonic oscillation and microwave heating functions.

6. The method for synthesizing the micro-nano three-dimensional structure zinc phosphate pigment according to any one of claims 1 to 5, characterized in that: The mass ratio of the soluble zinc salt and the anionic surfactant in step S1 is set between 3:1 and 5:1, and the mass ratio of the phosphoric acid, the soluble phosphate and the organic solvent in step S2 is set between 3:1:1 and 7.5:1.5:

1.

7. A micro-nano three-dimensional structure zinc phosphate pigment, characterized in that: The micro-nano three-dimensional structured zinc phosphate pigment is synthesized according to the synthesis method of any one of claims 1 to 6 and has a three-dimensional spatial structure.

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