Rust-bearing coating modified by loaded rust inhibitor nanosheets and preparation method and application thereof

Abstract

The present invention discloses a rust-resistant coating modified with a loaded rust-resistant nanosheet, a preparation method, and an application thereof. The rust-resistant coating comprises a coating system and a curing system; the coating system comprises, by mass, 30-50 parts of a matrix coating, 0.1-5 parts of a loaded rust-resistant nanosheet, 5-35 parts of an anticorrosive filler, 0.5-3 parts of a dispersant, 1-3 parts of a defoamer, 0.5-5 parts of a leveling agent, and 5-15 parts of a diluent; the curing system comprises, by mass, 5-15 parts of a curing agent; the loaded rust-resistant nanosheet is a boron nitride nanosheet loaded with strontium phytate. The present invention adds boron nitride nanosheets loaded with strontium phytate to the rust-resistant coating system, which can avoid the problem of rapid leakage and failure caused by the rust-resistant rust being directly added to the coating. The rust-resistant coating of the present invention has multiple synergistic effects of barrier shielding, passivation stabilization, and chelation conversion, greatly extending the service life of the coating and shortening the coating and maintenance cycle of the rusted substrate.

Description

Technical Field

[0001] The invention relates to the field of metal anti-corrosion coating materials, and in particular to a rust-bearing coating modified by loading rust inhibitor nanosheets, a preparation method and an application thereof. Background Art

[0002] Steel is the foundation of human industrial civilization, but it's also a major source of carbon emissions. According to the World Steel Association, global average carbon emissions per ton of steel are approximately 1.85 tons. Statistics show that nearly a quarter of all steel produced worldwide corrodes annually, resulting in direct economic losses of approximately $700 billion. Therefore, the rational utilization of corroded steel substrates is crucial for energy conservation and emission reduction. Protecting and extending the lifespan of corroded steel substrates has positive implications for energy conservation and emission reduction.

[0003] Reapplying rusted coatings is one of the most effective methods for reusing corroded steel substrates. Rust inhibitors in the coatings react with the rusted steel substrate through a conversion / inhibition process, slowing down the kinetic mechanism and inhibiting further corrosion. However, direct incorporation of rust inhibitors into rusted coatings has poor compatibility, potentially leading to failures such as accelerated corrosion due to excessive incorporation and susceptibility to environmental effects. This is primarily due to the random, free diffusion of the rust inhibitor.

[0004] Therefore, how to construct a long-term slow release system of rust inhibitors to extend the service life of rusted steel substrates is lacking in the application of rust-resistant coatings to rusted steel substrates. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem of diffusion failure of rust inhibitors, overcome the tedious rust removal process, thereby achieving long-term release of corrosion inhibitors, enhancing the corrosion protection performance of the coating, and forming an epoxy rust-resistant coating material that combines barrier shielding, passivation stabilization, and chelation conversion.

[0006] In order to achieve the above-mentioned object, the present invention provides a rust-resistant coating modified by nanosheets loaded with rust inhibitor, comprising a coating system and a curing system;

[0007] The coating system comprises, by mass, 30-50 parts of base coating, 0.1-5 parts of nanosheets loaded with rust inhibitor, 5-35 parts of anticorrosive filler, 0.5-3 parts of dispersant, 1-3 parts of defoaming agent, 0.5-5 parts of leveling agent, and 5-15 parts of diluent;

[0008] The curing system comprises, by mass, 5-15 parts of a curing agent;

[0009] The rust inhibitor-loaded nanosheets are boron nitride nanosheets loaded with strontium phytate.

[0010] It should be noted that in the present invention, the types of matrix coating, anticorrosive filler, dispersant, defoamer, leveling agent, diluent, and curing agent are not strictly limited and can be selected according to conventional requirements in the field. For example, the matrix coating can be selected from at least one of epoxy resin, polyacrylic resin, polyurethane resin, fluorocarbon resin, silicone resin, etc.; the anticorrosive filler can be at least one of barium sulfate, titanium dioxide, calcium carbonate, talc, etc.; the dispersant can be at least one of anionic polymer compounds, polymeric carboxylic acids, and siloxane copolymers; the defoamer can be a polymeric acrylate; the leveling agent can be a polyether-modified polysiloxane; and the diluent can be at least one of xylene and n-butanol. Preferably, the matrix coating is an epoxy resin, and the corresponding curing agent is a curing agent compatible with the epoxy resin, such as an amine epoxy curing agent such as polyamide, aliphatic amine, or aromatic amine.

[0011] Furthermore, the preparation method of the strontium phytate-loaded boron nitride nanosheets comprises:

[0012] Soluble strontium salt and phytic acid are dissolved in a solvent, and then boron nitride nanosheets are added and mixed, followed by a solvent thermal reaction to obtain boron nitride nanosheets loaded with strontium phytate.

[0013] Furthermore, the molar ratio of the soluble strontium salt to phytic acid is 5-10:1;

[0014] The mass ratio of the soluble strontium salt to the boron nitride nanosheets is 1-3:0.5-1.5;

[0015] The mass volume ratio of the soluble strontium salt to the solvent is 2-10 g: 50-150 mL. The type of the soluble strontium salt is not strictly limited, and illustratively it can be at least one of strontium chloride, strontium nitrate, strontium acetate, etc.

[0016] Furthermore, the length of the boron nitride nanosheet is 3-30 μm, and the thickness of the sheet is 1-30 nm.

[0017] Furthermore, the solvent includes at least one of water, ethanol and acetone.

[0018] Furthermore, the solvent thermal reaction is maintained at 120-180° C. for 6-24 hours.

[0019] Furthermore, the curing system further comprises 0-3 parts by mass of an anti-flash rust agent.

[0020] The present invention also provides a method for preparing the above-mentioned rust-bearing paint modified with nanosheets loaded with rust inhibitor, which comprises, in parts by mass,

[0021] 30-50 parts of a base coating, 5-35 parts of an anticorrosive filler, 0.5-3 parts of a dispersant, 1-3 parts of a defoamer, 0.5-5 parts of a leveling agent, and 5-15 parts of a diluent are mixed and ground, and then 0.1-5 parts of a rust inhibitor-loaded nanosheet is added and further mixed and ground to obtain a coating system, wherein the rust inhibitor-loaded nanosheet is a boron nitride nanosheet loaded with strontium phytate;

[0022] A curing system consisting of 5-15 parts of a curing agent is mixed with a coating system to obtain a rust-bearing coating modified with nanosheets loaded with a rust-inhibiting agent.

[0023] Furthermore, the curing system further comprises 0-3 parts of an anti-flash rust agent.

[0024] The present invention also provides the application of the rust-bearing paint modified by the rust-inhibiting agent-loaded nanosheets in the field of metal corrosion protection.

[0025] The concept of the present invention is to add boron nitride nanosheets loaded with strontium phytate to the rust-resistant paint composition. Boron nitride nanosheets have excellent chemical stability and physical barrier properties. They set up a maze of paths on the metal surface, extending the diffusion path of the corrosive medium and slowing the occurrence of corrosion. Boron nitride also has good electrical insulation. When used for metal protection, it can prevent the transmission of electrons between the metal surface and the corrosive medium, thereby slowing the corrosion rate of the metal. The molecular structure of strontium phytate contains multiple negatively charged phosphate groups. These groups can undergo a strong chelation reaction with the metal substrate to form a stable complex. During this process, strontium ions are released and adsorbed on the metal surface through physical adsorption, forming an adsorption film. This film can prevent corrosive media such as oxygen and water from directly contacting the metal surface, thereby slowing the corrosion rate of the metal. Boron nitride nanosheets loaded with strontium phytate have common advantages and improve the performance of rust-resistant paint.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention adds boron nitride nanosheets loaded with strontium phytate to the tape embroidery coating system, which can avoid the problem of rapid leakage and failure of rust inhibitors when they are directly added to the coating.

[0028] (2) The embroidery coating constructed by the present invention has multiple synergistic effects of barrier shielding, passivation stabilization, and chelation conversion, which greatly prolongs the service life of the coating and can shorten the coating and maintenance cycle of the rusted substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 shows a scanning electron microscope image of the boron nitride nanosheets used in Example 1;

[0031] Figure 2 shows a scanning electron microscope image of the boron nitride nanosheets loaded with strontium phytate prepared in Example 1;

[0032] Figure 3 A photograph of a test panel not coated with embroidery paint is shown;

[0033] Figure 4 A photograph of a test panel coated with the embroidery coating of Example 1 after 600 hours of neutral salt spray testing is shown;

[0034] Figure 5 The following is a photograph of the test panel coated with the embroidery paint of Comparative Example 1 after 600 hours of neutral salt spray testing;

[0035] Figure 6 The following is a photograph of the test panel coated with the embroidery paint of Comparative Example 2 after 600 hours of neutral salt spray testing. DETAILED DESCRIPTION

[0036] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the specific embodiments of the present invention and the accompanying drawings. Obviously, the embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0038] It should be noted that the boron nitride nanosheets in the examples and comparative examples were prepared by boron nitride ball milling, and had a length of about 25 μm and a sheet thickness of about 3 nm.

[0039] Example 1

[0040] A method for preparing a rust-resistant coating modified with nanosheets loaded with a rust inhibitor comprises the following steps, in parts by mass:

[0041] Step (1) adding 2 parts of anionic polymer compound, 2 parts of polyether-modified polysiloxane, 3 parts of polymer acrylate, 20 parts of barium sulfate, 4 parts of xylene, and 6 parts of n-butanol to 50 parts of epoxy resin, mixing and grinding for 1 hour, then adding 2 parts of boron nitride nanosheets loaded with strontium phytate and continuing to mix and grind for 20 minutes, filtering through a 100-mesh sieve to obtain a coating system, and packaging for later use;

[0042] Step (2) 6 parts of polyamide, 4 parts of fatty amine, and 1 part of anti-flash rust agent are stirred and mixed to obtain a curing system;

[0043] Step (3) uniformly mixes the coating system and the curing system to obtain a rust-bearing coating modified with rust-inhibiting agent nanosheets.

[0044] The preparation method of boron nitride nanosheets loaded with strontium phytate includes:

[0045] 4.76 g of strontium chloride (30 mmol) and 2.98 mL of 70% phytic acid (5 mmol) were dissolved in a beaker of 100 mL of deionized water. Then, 4.96 g of boron nitride nanosheets were added and stirred evenly. The mixture was transferred to a polytetrafluoroethylene reactor and heated to 150 °C for hydrothermal reaction for 12 h. After the reaction, the mixture was naturally cooled to room temperature. The insoluble matter was collected and washed three times, dried at 60 °C for 24 h, and ground through a 100-mesh sieve to obtain boron nitride nanosheets loaded with strontium phytate.

[0046] Example 2

[0047] A method for preparing a rust-resistant coating modified with nanosheets loaded with a rust inhibitor comprises the following steps, in parts by mass:

[0048] Step (1) adding 3 parts of anionic polymer compound, 3 parts of polyether-modified polysiloxane, 2 parts of polymer acrylate, 25 parts of barium sulfate, 8 parts of xylene, and 4 parts of n-butanol to 42 parts of epoxy resin, mixing and grinding for 1 hour, then adding 3 parts of boron nitride nanosheets loaded with strontium phytate and continuing to mix and grind for 20 minutes, filtering through a 100-mesh sieve to obtain a coating system, and packaging for later use;

[0049] Step (2) 4 parts of polyamide, 4 parts of fatty amine, and 2 parts of anti-flash rust agent are stirred and mixed to obtain a curing system;

[0050] Step (3) uniformly mixes the coating system and the curing system to obtain a rust-bearing coating modified with rust-inhibiting agent nanosheets.

[0051] The preparation method of boron nitride nanosheets loaded with strontium phytate includes:

[0052] 7.14 g of strontium chloride (45 mmol) and 4.47 mL of 70% phytic acid (7.5 mmol) were dissolved in a beaker of 100 mL of deionized water, and then 4.96 g of boron nitride nanosheets were added and stirred evenly. The mixture was transferred to a polytetrafluoroethylene reactor and heated to 150 °C for hydrothermal reaction for 12 h. After the reaction, the mixture was naturally cooled to room temperature. The insoluble matter was collected and washed three times, dried at 60 °C for 24 h, and ground through a 200-mesh sieve to obtain boron nitride nanosheets loaded with strontium phytate.

[0053] Example 3

[0054] A method for preparing a rust-resistant coating modified with nanosheets loaded with a rust inhibitor comprises the following steps, in parts by mass:

[0055] Step (1) adding 3 parts of anionic polymer compound, 3 parts of polyether-modified polysiloxane, 2 parts of polymer acrylate, 23 parts of barium sulfate, 5 parts of xylene, and 8 parts of n-butanol to 45 parts of epoxy resin, mixing and grinding for 1 hour, then adding 1 part of boron nitride nanosheets loaded with strontium phytate and continuing to mix and grind for 20 minutes, filtering through a 100-mesh sieve to obtain a coating system, and packaging for later use;

[0056] Step (2) 4 parts of polyamide, 5 parts of fatty amine, and 2 parts of anti-flash rust agent are stirred and mixed to obtain a curing system;

[0057] Step (3) uniformly mixes the coating system and the curing system to obtain a rust-bearing coating modified with rust-inhibiting agent nanosheets.

[0058] The preparation method of boron nitride nanosheets loaded with strontium phytate includes:

[0059] 7.14 g of strontium chloride (45 mmol) and 4.47 mL of 70% phytic acid (7.5 mmol) were dissolved in a beaker of 100 mL of deionized water, and then 2.48 g of boron nitride nanosheets were added and stirred evenly. The mixture was transferred to a polytetrafluoroethylene reactor and heated to 150 °C for hydrothermal reaction for 12 h. After the reaction, the mixture was naturally cooled to room temperature. The insoluble matter was collected and washed three times, dried at 60 °C for 24 h, and ground through a 200-mesh sieve to obtain boron nitride nanosheets loaded with strontium phytate.

[0060] Example 4

[0061] The process is basically the same as Example 1, except that no flash rust inhibitor is added in step (2).

[0062] Example 5

[0063] The method is basically the same as Example 1, except that in the preparation method of boron nitride nanosheets loaded with strontium phytate, the amounts of strontium chloride and phytic acid used are 25 mmol and 5 mmol, respectively.

[0064] Example 6

[0065] The method is basically the same as Example 1, except that in the preparation method of boron nitride nanosheets loaded with strontium phytate, the amounts of strontium chloride and phytic acid used are 50 mmol and 5 mmol, respectively.

[0066] Comparative Example 1

[0067] A method for preparing a rust-resistant coating modified with boron nitride nanosheets comprises the following steps, calculated in parts by mass:

[0068] Step (1) adding 3 parts of anionic polymer compound, 3 parts of polyether-modified polysiloxane, 2 parts of polymer acrylate, 25 parts of barium sulfate, 8 parts of xylene, and 4 parts of n-butanol to 42 parts of epoxy resin, mixing and grinding for 1 hour, then adding 3 parts of boron nitride nanosheets and continuing to mix and grind for 20 minutes, filtering through a 100-mesh sieve to obtain a coating system, and packaging for later use;

[0069] Step (2) 4 parts of polyamide, 4 parts of fatty amine, and 2 parts of anti-flash rust agent are stirred and mixed to obtain a curing system;

[0070] Step (3) uniformly mixes the coating system and the curing system to obtain a rust-resistant coating modified with boron nitride nanosheets.

[0071] Comparative Example 2

[0072] A method for preparing a rust-resistant coating modified with strontium phytate comprises the following steps, calculated by weight:

[0073] Step (1) adding 3 parts of anionic polymer compound, 3 parts of polyether-modified polysiloxane, 2 parts of polymer acrylate, 25 parts of barium sulfate, 8 parts of xylene, and 4 parts of n-butanol to 42 parts of epoxy resin, mixing and grinding for 1 hour, then adding 3 parts of strontium phytate and continuing to mix and grind for 20 minutes, filtering through a 100-mesh sieve to obtain a coating system, and packaging for later use;

[0074] Step (2) 4 parts of polyamide, 4 parts of fatty amine, and 2 parts of anti-flash rust agent are stirred and mixed to obtain a curing system;

[0075] Step (3) uniformly mixes the coating system and the curing system to obtain a rust-resistant coating modified with strontium phytate.

[0076] The preparation method of strontium phytate is the same as that in Example 1 and will not be repeated here.

[0077] The micromorphology of the boron nitride nanosheets used in Example 1 and the prepared boron nitride nanosheets loaded with strontium phytate were observed using a scanning electron microscope. The results were as follows: Figure 1 and Figure 2 As shown in the figure, it can be seen that the boron nitride nanosheets exhibit a blocky structure formed by stacked sheets. At the same time, the boron nitride nanosheets loaded with strontium phytate have some small particles accumulated on the surface of the boron nitride nanosheets, indicating that strontium phytate was successfully loaded on the surface of the boron nitride nanosheets through a simple one-step hydrothermal reaction.

[0078] Refer to the standard HG / T 5173-2017 Water-based primer for rust-resistant coatings. Hot-rolled steel plates were used as test objects. After sandblasting, salt spray test, and wet heat test, the surface rust of the steel plates was manually removed with a wire brush. The firmly attached rust was retained. After drying, the surface dust was blown off with high-pressure air to obtain the following Figure 3 The test plate shown in the figure was then immediately coated with the embroidery coatings prepared in the examples and comparative examples, and the resulting plates were kept in neutral salt spray for 600 hours, and the morphology was observed. The photographs of the test plates made with the embroidery coatings prepared in Example 1, Comparative Example 1, and Comparative Example 2 are shown in the figure below. Figure 4 、 Figure 5 and Figure 6 As shown. It can be seen that the rust-resistant coating prepared by the boron nitride nanosheet modified with strontium phytate in comparative example 1 and the rust-resistant coating prepared by the strontium phytate in comparative example 2 both showed red rust on the surface of the coating, while the rust-resistant coating prepared by the rust-resistant coating loaded with nanosheet modified with rust inhibitor in Example 1 showed no obvious rust or blistering on the surface of the coating. This shows that the boron nitride nanosheet loaded with strontium phytate has better corrosion resistance than the boron nitride nanosheet. The rust-resistant coatings of Examples 4-6 were also tested, and the results were similar to those of Example 1, showing good rust-resistant and corrosion-resistant performance.

[0079] The reason why the embroidery coating of the present invention has excellent rust-proofing and rust-inhibiting properties is that the boron nitride nanosheets have excellent chemical stability and physical barrier capabilities, forming a maze of paths through the metal surface, extending the diffusion path of the corrosive medium and slowing down the occurrence of corrosion. At the same time, boron nitride also has good electrical insulation. When used for metal protection, it can prevent the transmission of electrons between the metal surface and the corrosive medium, thereby slowing down the corrosion rate of the metal. The strontium phytate molecular structure contains multiple negatively charged phosphate groups. These groups can undergo a strong chelate reaction with the metal substrate to form a stable complex. During this process, strontium ions are released and adsorbed on the metal surface by physical adsorption, forming an adsorption film. This film can prevent corrosive media such as oxygen and water from directly contacting the metal surface, thereby slowing down the corrosion rate of the metal. However, using boron nitride or strontium phytate alone as a rust inhibitor can lead to coating deactivation due to the poor compatibility of boron nitride with the coating matrix. Furthermore, under the same test conditions, the coating containing only strontium phytate exhibited more severe rust, indicating that the premature release of phosphate prevented the long-term effectiveness of strontium phytate. Boron nitride nanosheets loaded with strontium phytate share common advantages: strontium phytate and boron nitride exhibit a synergistic effect, allowing the strontium phytate-loaded boron nitride nanosheets to be well dispersed in the coating, inhibiting the premature release of active groups in strontium phytate and thus improving the performance of the rust-resistant coating.

[0080] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rust-resistant coating modified with nanosheets loaded with rust inhibitor, characterized in that: Including coating system and curing system; The coating system comprises, by mass, 30-50 parts of base coating, 0.1-5 parts of nanosheets loaded with rust inhibitor, 5-35 parts of anticorrosive filler, 0.5-3 parts of dispersant, 1-3 parts of defoaming agent, 0.5-5 parts of leveling agent, and 5-15 parts of diluent; The curing system comprises, by mass, 5-15 parts of a curing agent; The rust inhibitor-loaded nanosheets are boron nitride nanosheets loaded with strontium phytate; The preparation method of the boron nitride nanosheets loaded with strontium phytate comprises: Soluble strontium salt and phytic acid are dissolved in a solvent, and then boron nitride nanosheets are added and mixed, followed by a solvent thermal reaction to obtain boron nitride nanosheets loaded with strontium phytate.

2. The rust-resistant paint modified with nanosheets loaded with rust inhibitor according to claim 1, characterized in that: The molar ratio of the soluble strontium salt to phytic acid is 5-10:1; The mass ratio of the soluble strontium salt to the boron nitride nanosheets is 1-3:0.5-1.5; The mass volume ratio of the soluble strontium salt to the solvent is 2-10 g:50-150 mL.

3. The rust-resistant paint modified with nanosheets loaded with rust inhibitor according to claim 1, characterized in that: The length of the boron nitride is 3-30 μm, and the thickness of the sheet is 1-30 nm.

4. The rust-resistant paint modified with nanosheets loaded with rust inhibitor according to claim 1, characterized in that: The solvent includes at least one of water, ethanol and acetone.

5. The rust-resistant paint modified with nanosheets loaded with rust inhibitor according to claim 1, characterized in that: The solvent thermal reaction is maintained at 120-180° C. for 6-24 hours.

6. The rust-resistant paint modified with nanosheets loaded with rust inhibitor according to claim 1, characterized in that: The curing system further comprises 0-3 parts by mass of an anti-flash rust agent.

7. A method for preparing a rust-bearing coating modified with nanosheets loaded with a rust inhibitor according to any one of claims 1 to 6, characterized in that: In parts by mass, 30-50 parts of a base coating, 5-35 parts of an anticorrosive filler, 0.5-3 parts of a dispersant, 1-3 parts of a defoamer, 0.5-5 parts of a leveling agent, and 5-15 parts of a diluent are mixed and ground, and then 0.1-5 parts of a rust inhibitor-loaded nanosheet is added and further mixed and ground to obtain a coating system, wherein the rust inhibitor-loaded nanosheet is a boron nitride nanosheet loaded with strontium phytate; A curing system consisting of 5-15 parts of a curing agent is mixed with a coating system to obtain a rust-bearing coating modified with nanosheets loaded with a rust-inhibiting agent.

8. The method for preparing the rust-bearing coating modified with rust-inhibiting agent nanosheets according to claim 7, characterized in that: The curing system also includes 0-3 parts of an anti-flash rust agent.

9. Use of a rust-bearing paint modified with rust inhibitor nanosheets loaded thereon according to any one of claims 1 to 6 in the field of metal corrosion protection.

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