Phytic acid supramolecular modified boron nitride bifunctional coating composition and preparation method thereof

Abstract

The invention provides a phytic acid supramolecular modified boron nitride bifunctional coating composition and a preparation method thereof, the coating composition comprises a phytic acid supramolecular modified boron nitride dispersion liquid, and the phytic acid supramolecular modified boron nitride dispersion liquid contains hydroxylated boron nitride with polydopamine polymerized on the surface and phytic acid supramolecules. Hydroxylated boron nitride is modified by polydopamine, so that the dispersity and labyrinth effect of boron nitride in water-borne epoxy resin are improved, and boron nitride can serve as a reaction platform for phytic acid supramolecular assembly; phytic acid and melamine in the phytic acid supramolecules are rich in N and P elements and can play a flame-retardant role, Ce < 3 + > can catalyze CO to be converted into CO2 in the combustion process, and generation of toxic gas is reduced; melamine, phytic acid and Ce < 3 + > form ionic bonds through coordination and protonation and are self-assembled on the surface of BNO, so that the compatibility of boron nitride in matrix resin is enhanced, the anti-corrosion effect of the product can be effectively improved, and the service life of the organic coating is further prolonged.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion and flame-retardant coating technology, and provides a phytic acid supramolecular modified boron nitride bifunctional coating composition and its preparation method. Background Technology

[0002] With the rapid development of marine engineering, new energy equipment, and modern chemical facilities, offshore and coastal steel structures face severe corrosion and fire risks, placing higher demands on the multi-functional integrated performance of protective coatings. Traditional protection systems typically apply anti-corrosion and fire-retardant coatings separately, which is not only cumbersome but also suffers from weak interlayer adhesion, easy peeling, and high overall costs. Although some integrated anti-corrosion / flame-retardant coatings have emerged on the market, their performance is often limited by factors such as poor filler dispersibility, insufficient interfacial compatibility, and low flame-retardant efficiency, making it difficult to achieve long-term effective protection in high-temperature and corrosive environments.

[0003] Among numerous functional fillers, boron nitride nanosheets are considered ideal candidates for achieving thin-film, high-efficiency coatings due to their excellent thermal stability, gas barrier properties, and insulation performance. However, their high surface energy leads to easy aggregation in polymer matrices, making it difficult to form a stable physical barrier, limiting the "maze effect," and also affecting the overall mechanical and corrosion-resistant properties of the coating. Furthermore, traditional flame-retardant systems often rely on high addition levels or halogen-containing components, which are insufficient in terms of environmental friendliness and toxicity, and few designs can simultaneously achieve flame retardancy in both the gas and condensed phases while suppressing the generation of toxic fumes.

[0004] CN118978825B employs a method of modifying boron nitride with phosphorus-nitrogen aniline oligomers. This involves preparing a modified boron nitride dispersion and combining it with a matrix resin, an intumescent flame-retardant system, and functional additives to form a fire-retardant and corrosion-resistant dual-function coating composition. The compatibility is enhanced by using ammonium dihydrogen phosphate-terminated aniline oligomers to modify boron nitride, and the flame-retardant performance is improved by combining it with a composite ternary intumescent system. However, this coating composition has shortcomings in terms of impedance and requires further improvement.

[0005] Therefore, it is necessary to provide a phytic acid supramolecular modified boron nitride bifunctional coating composition and its preparation method, which can simultaneously achieve the dual effects of corrosion prevention and flame retardancy, and also improve environmental protection. Summary of the Invention

[0006] To address the problems mentioned in the background section, this invention provides a phytic acid supramolecular modified boron nitride bifunctional coating composition and its preparation method. This invention introduces Ce in the presence of melamine and phytic acid. 3+PMC is formed, which further combines with hydroxylated boron nitride with polydopamine polymerized on its surface to construct a stable supramolecular assembly structure, thus preparing a modified boron nitride dispersion. This significantly improves the dispersibility and interfacial compatibility of boron nitride nanosheets in aqueous epoxy resin, enhances the physical barrier of the coating, and achieves the dual effects of flame retardancy and corrosion resistance. The modified boron nitride dispersion prepared in this invention contains abundant N and P elements, which can impart excellent flame retardant properties to the coating; while Ce... 3+ At high temperatures, it can catalyze the conversion of CO to CO2, effectively reducing the release of toxic gases, thereby achieving a highly efficient synergy between anti-corrosion and flame-retardant properties and extending the service life of steel structure coatings.

[0007] In a first aspect, the present invention provides a phytic acid supramolecular modified boron nitride bifunctional coating composition, comprising a phytic acid supramolecular modified boron nitride dispersion. The phytic acid supramolecular modified boron nitride dispersion contains hydroxylated boron nitride (BNO@PDA) with polydopamine polymerized on its surface and phytic acid supramolecular (PMC). The structural formula of the hydroxylated boron nitride of the polydopamine is: (I); The structural formula of the phytic acid supramolecular is as follows: (II).

[0008] In some embodiments, the impedance of the coating composition is ≥ 3.83 × 10⁻⁶. 8 Ω·cm 2 Preferably, the impedance is ≥ 4 × 10⁻⁶. 8 Ω·cm 2 Preferably, the impedance is ≥ 5 × 10⁻⁶. 8 Ω·cm 2 Preferably, the impedance is ≥ 5.5 × 10⁻⁶. 8 Ω·cm 2 .

[0009] In some embodiments, the limiting oxygen index (LOI) of the coating composition is ≥25%, preferably ≥27%.

[0010] In some embodiments, the phytic acid supramolecular (PMC) is an aggregate formed by coordination of phytic acid (PA in this invention), melamine (MA), and cerium nitrate hexahydrate in deionized water.

[0011] In some embodiments, the mass ratio of phytic acid (PA), melamine (MA), and cerium nitrate hexahydrate is (2-2.5):(1-1.5):(1-1.5), preferably any one of the ranges consisting of 2:1:1, 2.5:1.5:1.5, 2.5:1:1, 2:1.5:1.5, or any two of the above values. In some embodiments, the coordination reaction is carried out at 15-35°C for 20-40 min, preferably any one of the ranges consisting of 15°C, 20°C, 25°C, 30°C, 35°C, or any two of the above values, preferably any one of the ranges consisting of 20 min, 25 min, 30 min, 40 min, or any two of the above values.

[0012] In some embodiments, the surface-polymerized polydopamine-coated hydroxylated boron nitride (BNO@PDA) is obtained by stirring and polymerizing hydroxylated boron nitride (BNO) and dopamine (DA) in Tris buffer.

[0013] In some embodiments, the Tris buffer is a Tris buffer with pH 8.5. In some embodiments, the specific preparation process of the hydroxylated boron nitride with polydopamine polymerized on its surface is as follows: hydroxylated boron nitride is dispersed in ethanol to obtain a mixed solution; Tris buffer is added and dispersed evenly; dopamine hydrochloride is added, and the reaction is carried out at 55-65℃ for 6-8 hours until polymerization is complete. In some embodiments, the mass ratio of the mixed solution to the Tris buffer is (5~10):1, preferably 5:1, 6:1, 7:1, 8:1, 10:1, or any two of the above values ​​forming a range. In some embodiments, the mass ratio of hydroxylated boron nitride (BNO) to dopamine hydrochloride (DA) is (1~2):(1~2), preferably 1:1, 1:1.5, 1:2, 1.5:1, 2:1, or any two of the above values ​​forming a range. In some embodiments, the boron hydroxynitride is ultrasonically dispersed in ethanol for 20-40 min, preferably 20 min, 25 min, 30 min, 40 min, or any two of the above values. In some embodiments, after adding Tris buffer, the mixture is ultrasonically dispersed for 20-40 min, preferably 20 min, 25 min, 30 min, 40 min, or any two of the above values. In some embodiments, the polymerization reaction is carried out at 60°C for 8 h.

[0014] In some embodiments, the hydroxylated boron nitride (BNO) is obtained by calcining boron nitride (BN) and deionized water at 850-950 °C in a nitrogen atmosphere. In some embodiments, the calcination temperature is 850-950 °C, preferably any one of the following ranges: 850 °C, 860 °C, 870 °C, 880 °C, 890 °C, 900 °C, 910 °C, 920 °C, 930 °C, 940 °C, 950 °C, or any two of the above values. In some embodiments, the holding time for calcination is 10-120 min. Preferably, the holding time is any one of the following ranges: 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 80 min, 100 min, 120 min, or any two of the above values.

[0015] In some embodiments, the coating composition includes a matrix resin, a phytic acid supramolecular modified boron nitride dispersion, functional additives, and a curing agent.

[0016] In some embodiments, the matrix resin is selected from at least one of waterborne epoxy resin, silicone resin, acrylic resin, polyurethane resin, polyester resin, and alkyd resin. In some embodiments, the curing agent is selected from at least one of diaminodiphenylmethane, polyamide, diaminodiphenyl sulfone, m-phenylenediamine, m-phenylenediamine, and polyetheramine. In some embodiments, the functional additives include at least one of leveling agents, defoamers, dispersants, and anti-settling agents. In some embodiments, the functional additives include at least one of BYK-333 leveling agent, BYK-066N defoamer, BYK-P104 dispersant, and BYK-410 anti-settling agent.

[0017] In some embodiments, the coating composition, by weight, comprises 100 parts of a base resin, 80-120 parts of a phytic acid supramolecular modified boron nitride dispersion, 0.94 parts of a functional additive, and 25 parts of a curing agent. In some embodiments, the mass concentration of the phytic acid supramolecular modified boron nitride dispersion is 0.5-5%, preferably 0.5%, 1%, 2%, 3%, 4%, 5%, or any two of the above values ​​forming a range.

[0018] Secondly, this invention provides a method for preparing a phytic acid supramolecular modified boron nitride bifunctional coating composition, comprising the following steps: S1. Hydroxylated boron nitride is obtained by calcining boron nitride and deionized water in a nitrogen atmosphere. S2. A solution of hydroxylated boron nitride with polydopamine surface polymerized on the surface is obtained by stirring and polymerizing hydroxylated boron nitride and dopamine in Tris buffer. S3, phytic acid, melamine and cerium nitrate hexahydrate are stirred in deionized water and assembled through coordination to form phytic acid supramolecular aggregates; S4. After the solution of hydroxylated boron nitride with polydopamine polymerized on the surface and the solution of phytic acid supramolecular were mixed and reacted completely, the phytic acid supramolecular modified boron nitride powder was obtained by centrifugation, washing and drying. S5. Phytic acid supramolecular modified boron nitride powder was dissolved in deionized water to prepare a phytic acid supramolecular modified boron nitride dispersion. S6, matrix resin, phytic acid supramolecular modified boron nitride dispersion, functional additives and curing agent are uniformly dispersed by high-speed disperser to obtain epoxy resin components; S7, epoxy resin components and curing agent are dispersed evenly by high-speed dispersion to obtain coating composition.

[0019] In some embodiments, in S1, the calcination temperature is 850-950℃, preferably any one of the following ranges: 850℃, 860℃, 870℃, 880℃, 890℃, 900℃, 910℃, 920℃, 930℃, 940℃, 950℃, or any two of the above values. In some embodiments, the holding time for calcination is 10-120 min. Preferably, the holding time is any one of the following ranges: 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 80 min, 100 min, 120 min, or any two of the above values.

[0020] In some embodiments, in S2, the Tris buffer is a Tris buffer with pH 8.5. In some embodiments, the specific preparation process of the hydroxylated boron nitride with polydopamine polymerized on its surface is as follows: hydroxylated boron nitride is dispersed in ethanol to obtain a mixed solution; Tris buffer is added and dispersed evenly; dopamine hydrochloride is added, and the reaction is carried out at 55-65℃ for 6-8 hours. After polymerization, the solution is obtained by centrifugation, washing, and drying. In some embodiments, the mass ratio of the mixed solution to the Tris buffer is (5~10):1, preferably 5:1, 6:1, 7:1, 8:1, 10:1, or any two of the above values ​​forming a range. In some embodiments, the mass ratio of hydroxylated boron nitride (BNO) to dopamine hydrochloride (DA) is (1~2):(1~2), preferably 1:1, 1:1.5, 1:2, 1.5:1, 2:1, or any two of the above values ​​forming a range. In some embodiments, the boron hydroxynitride is ultrasonically dispersed in ethanol for 20-40 min, preferably 20 min, 25 min, 30 min, 40 min, or any two of the above values. In some embodiments, after adding Tris buffer, the mixture is ultrasonically dispersed for 20-40 min, preferably 20 min, 25 min, 30 min, 40 min, or any two of the above values. In some embodiments, the polymerization reaction is carried out at 60°C for 8 h.

[0021] In some embodiments, in S3, the mass ratio of phytic acid (PA), melamine (MA), and cerium nitrate hexahydrate is (2-2.5):(1-1.5):(1-1.5), preferably any one of the ranges consisting of 2:1:1, 2.5:1.5:1.5, 2.5:1:1, 2:1.5:1.5, or any two of the above values. In some embodiments, the coordination reaction is carried out at 15-35°C for 20-40 min, preferably any one of the ranges consisting of 15°C, 20°C, 25°C, 30°C, 35°C, or any two of the above values, preferably any one of the ranges consisting of 20 min, 25 min, 30 min, 40 min, or any two of the above values.

[0022] In some embodiments, the mass ratio of phytic acid (PA) to hydroxylated boron nitride is (1~2):(1~2), preferably 1:1, 1:1.5, 1:2, 1.5:1, 2:1, or any two of the above values ​​forming a range.

[0023] In some embodiments, in step S4, the mixing reaction is carried out at 15-35°C for 12-16 hours, preferably within a range of 15°C, 20°C, 25°C, 30°C, 35°C, or any two of the above values, and preferably within a range of 12 hours, 14 hours, 15 hours, 16 hours, 18 hours, or any two of the above values. In some embodiments, centrifugation refers to centrifugation at 4000 rpm for 10 minutes. In some embodiments, drying refers to vacuum drying at 60°C for 12 hours. In some embodiments, washing is performed using an ethanol-water solution.

[0024] In some embodiments, the coating composition, by weight, comprises 100 parts of a base resin, 80-120 parts of a phytic acid supramolecular modified boron nitride dispersion, 0.94 parts of a functional additive, and 25 parts of a curing agent. In some embodiments, the mass concentration of the phytic acid supramolecular modified boron nitride dispersion is 0.5-5%, preferably 0.5%, 1%, 2%, 3%, 4%, 5%, or any two of the above values ​​forming a range.

[0025] In some embodiments, in S6, the uniform dispersion time is 1-2 hours, and the dispersion stirring speed is 1500-2000 r / min, preferably 1500 r / min, 1550 r / min, 1600 r / min, 1700 r / min, 1800 r / min, 1900 r / min, 2000 r / min, and any two of the above values ​​forming any one of the ranges.

[0026] In some embodiments, in S7, the uniform dispersion time is 1-2 hours, and the dispersion stirring speed is 1500-2000 r / min, preferably 1500 r / min, 1550 r / min, 1600 r / min, 1700 r / min, 1800 r / min, 1900 r / min, 2000 r / min, and any two of the above values ​​forming any one of the ranges.

[0027] Compared with the prior art, one of the above technical solutions has the following advantages or beneficial effects: The phytic acid supramolecular modified boron nitride bifunctional coating composition prepared in this invention possesses both flame retardant and anti-corrosion properties. Modification of hydroxylated boron nitride with polydopamine enhances the dispersibility and labyrinth effect of boron nitride in waterborne epoxy resins, while also serving as a reaction platform for phytic acid supramolecular assembly. The phytic acid and melamine in the phytic acid supramolecular structure are rich in N and P elements, which contribute to flame retardancy, and Ce... 3+ During combustion, it can catalyze the conversion of CO to CO2, reducing the generation of toxic gases; melamine, phytic acid, and Ce...3+ By forming ionic bonds through coordination and protonation, boron nitride self-assembles on the BNO surface, enhancing its compatibility with the matrix resin. This effectively improves the product's anti-corrosion effect and extends the service life of the organic coating.

[0028] 1. This invention comprises phytic acid, melamine, and cerium ions, which form a phytic acid supramolecular aggregate through molecular coordination and ionic bonding. This aggregate possesses multiple anti-corrosion and flame-retardant functions. Phytic acid and cerium ions synergistically act on the surface of the metal substrate, achieving passivation protection, "capturing" iron ions, and promoting the formation of stable complexes, thereby effectively inhibiting the corrosion process. Simultaneously, phytic acid, as a high-phosphorus source, plays a catalytic flame-retardant role during combustion. Cerium ions not only inhibit smoke generation but also catalyze the conversion of toxic gases into non-toxic substances. Melamine, as a high-nitrogen source, decomposes upon heating to release non-flammable gases such as NO and NO2, diluting the concentration of oxygen and combustible gases, thus exerting a gas-phase flame-retardant effect.

[0029] 2. This invention utilizes a polydopamine layer formed by the in-situ polymerization of dopamine hydrochloride on the surface of hydroxylated boron nitride in an alkaline environment, which acts as a key interfacial bridging agent similar to "double-sided tape." This structure not only provides a stable platform for the subsequent assembly of phytic acid supramoleculars but also significantly enhances the dispersibility and interfacial compatibility of boron nitride nanosheets in the epoxy resin matrix, effectively preventing filler agglomeration.

[0030] 3. This invention utilizes the large specific surface area of ​​two-dimensional boron nitride nanosheets to achieve uniform distribution within the coating, forming a dense "maze effect" that effectively blocks the penetration and diffusion of water, oxygen, and corrosive agents. Its inherent chemical stability and high-temperature resistance allow it to serve as a key skeletal component in the char layer during combustion, enhancing char layer strength, preventing coating cracking, and thus simultaneously improving the coating's corrosion resistance and fire resistance limit.

[0031] 4. This invention successfully prepared nitrogen and phosphorus-modified functionalized boron nitride nanosheets through multiple interactions, including π-π conjugation, hydrogen bonding, and ionic bonding, between phytic acid supramolecular elements and polydopamine-modified boron nitride. Furthermore, the abundant active groups in the phytic acid supramolecular elements can undergo ring-opening reactions with the epoxy groups in the epoxy resin and form covalent crosslinks with the amine groups in the curing agent, thereby achieving effective co-curing with the resin matrix. This structure greatly improves the compatibility between inorganic boron nitride and the organic resin matrix, enhances interfacial bonding, and thus significantly extends the overall service life of the coating.

[0032] 5. This invention integrates a ternary synergistic flame retardant system comprising phosphorus, nitrogen, two-dimensional boron nitride, and cerium-based inorganic flame retardants, comprehensively utilizing multiple advanced flame retardant technologies such as gas-phase-condensed-phase flame retardancy, smoke suppression and toxicity reduction, and halogen-free environmental protection. This system imparts excellent flame retardant properties to the coating while avoiding the environmental risks of traditional halogen-based flame retardants, demonstrating significant green and environmentally friendly significance. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the preparation process of phytic acid supramolecular modified boron nitride in Example 3 of the present invention.

[0034] Figure 2 The infrared spectra of surface hydroxylated boron nitride (BNO), surface polymerized polydopamine boron nitride (BNO@PDA), and phytic acid supramolecular modified boron nitride (BNO@PDA / PMC) in Examples 1 to 3 of this invention are shown.

[0035] Figure 3 This is the XPS spectrum of BNO@PDA / PMC in Embodiment 3 of the present invention.

[0036] Figure 4 The images show transmission electron microscopy (TEM) images and elemental distribution diagrams of BNO@PDA / PMC in Embodiment 3 of this invention.

[0037] Figure 5 The polarization curves of EP-BNO, EP-BNO@PDA, and EP-BNO@PDA / PMC in Examples 1 to 3 of the present invention are shown.

[0038] Terminology Explanation Certain embodiments of the invention will now be described in detail, examples of which are illustrated by the accompanying structural and chemical formulas. The invention is intended to cover all alternatives, modifications, and equivalents, all of which are included within the scope of the invention as defined in the claims. Those skilled in the art will recognize that many similar or equivalent methods and materials can be used to practice the invention. The invention is by no means limited to the methods and materials described herein. In the event that one or more of the incorporated documents, patents, and similar materials differ from or contradict this application (including, but not limited to, defined terminology, application of terminology, described techniques, etc.), this application shall prevail.

[0039] It should be further appreciated that certain features of the invention, for clarity, have been described in multiple independent embodiments, but may also be provided in combination in a single embodiment. Conversely, various features of the invention, for brevity, have been described in a single embodiment, but may also be provided individually or in any suitable sub-combination.

[0040] Unless otherwise stated, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. All patents and publications related to this invention are incorporated herein by reference in their entirety.

[0041] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0042] In the following content, all numbers disclosed herein, whether or not they use words such as "approximately" or "about," are approximate values. The value of each number may vary by 1%, 2%, 5%, 7%, 8%, 10%, 15%, or 20%. Whenever a number with a value of N is disclosed, any numbers with values ​​of N+ / -1%, N+ / -2%, N+ / -3%, N+ / -5%, N+ / -7%, N+ / -8%, N+ / -10%, N+ / -15%, or N+ / -20% will be explicitly disclosed, where "+ / -" indicates addition or subtraction. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention in any way. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of this disclosure. Such structures and techniques have also been described in many publications.

[0044] All reagents used in this invention can be purchased commercially or prepared by the methods described in this invention.

[0045] Example 1 (1) A ceramic boat containing 2.0 g of boron nitride (BN) powder was placed in the center of a tube furnace, and two ceramic boats containing water were placed on either side of it. The quartz tube was cleaned with nitrogen, and the tube furnace was heated to 900 °C at a heating rate of 10 °C / min and held at 900 °C for 0.5 h. After the tube furnace cooled to room temperature, the sample was removed and dispersed in deionized water. The dispersion was then centrifuged at 1000 rpm for 5 minutes, and the upper suspension was collected and freeze-dried to obtain surface-hydroxylated boron nitride (BNO) nanosheets.

[0046] (2) Place 100 g of deionized water and 1 g of BNO in a beaker and sonicate to obtain hydroxylated boron nitride dispersion 1.

[0047] (3) Place 100 g of deionized water and 5 g of BNO in a beaker and sonicate to obtain hydroxylated boron nitride dispersion 2.

[0048] (4) Place 100 g of waterborne epoxy resin, 100 g of hydroxylated boron nitride dispersion 1, 0.24 g of BYK-333 leveling agent, 0.24 g of BYK-066N defoamer, 0.24 g of BYK-P104 dispersant and 0.24 g of BYK-410 antisettling agent in a paint tank and disperse them evenly by vibration using a high-speed disperser to obtain epoxy resin component 1; 100 g of waterborne epoxy resin, 100 g of hydroxylated boron nitride dispersion 2, 0.24 g of BYK-333 leveling agent, 0.24 g of BYK-066N defoamer, 0.24 g of BYK-P104 dispersant and 0.24 g of BYK-410 anti-settling agent were placed in a paint tank and dispersed evenly by vibration using a high-speed disperser to obtain epoxy resin component 2.

[0049] (5) Add 25 g of waterborne polyamide curing agent to each of the two epoxy resin components in step (4), and disperse them evenly by high-speed dispersion to obtain coating 1 and coating 2.

[0050] (6) The coating 1 obtained in step (5) is applied to the steel plate using a wire bar coater to prepare coating sample 1. The steel plate used for testing corrosion resistance is coated with a thickness of about 60 μm.

[0051] (7) Pour the coating 2 obtained in step (5) into a preheated mold to prepare flame retardant test specimen 1.

[0052] (8) The samples obtained in steps (6) and (7) were cured sequentially at room temperature for 24 h, at 70 ℃ for 2 h, and at 120 ℃ for 4 h. After curing, performance tests were performed. The relevant test results are shown in Table 1. Figure 2 , Figure 3 and Figure 4 As shown.

[0053] Example 2 (1) 2.0 g of BNO prepared in Example 1 was added to 140 ml of ethanol solution and ultrasonically dispersed for 0.5 h. Then, 20 ml of Tris buffer was added to the above mixture and ultrasonically dispersed for 1.5 h. Then, 2.0 g of dopamine hydrochloride was added to the above mixture. The mixture was stirred at 60 °C for 8 h, centrifuged at 4000 rpm for 10 min, and the precipitate was washed three times with ethanol-water solution. The product was vacuum dried at 60 °C for 12 h to obtain BNO@PDA powder.

[0054] (2) Place 100 g of deionized water and 1 g of BNO@PDA powder in a beaker and sonicate to obtain BNO@PDA dispersion 1.

[0055] (3) Place 100 g of deionized water and 5 g of BNO@PDA in a beaker and sonicate to obtain BNO@PDA dispersion 2.

[0056] (4) Place 100 g of waterborne epoxy resin, 100 g of BNO@PDA dispersion 1, 0.24 g of BYK-333 leveling agent, 0.24 g of BYK-066N defoamer, 0.24 g of BYK-P104 dispersant and 0.24 g of BYK-410 antisettling agent in a paint tank and disperse them evenly by high-speed dispersion to obtain epoxy resin component 3; 100 g of waterborne epoxy resin, 100 g of BNO@PDA dispersion 2, 0.24 g of BYK-333 leveling agent, 0.24 g of BYK-066N defoamer, 0.24 g of BYK-P104 dispersant and 0.24 g of BYK-410 anti-settling agent were placed in a paint tank and dispersed evenly by vibration using a high-speed disperser to obtain epoxy resin component 4.

[0057] (5) Add 25 parts by weight of water-based polyamide curing agent to each of the steps (4), and disperse them evenly by high-speed dispersion to obtain coating 3 and coating 4.

[0058] (6) The coating 3 obtained in step (5) is applied to the steel plate using a wire bar coater to prepare coating sample 2. The steel plate used for testing corrosion resistance is coated with a thickness of about 60 μm.

[0059] (7) Pour the coating 4 obtained in step (5) into a preheated mold to prepare flame retardant test specimen 2.

[0060] (8) The samples obtained in steps (6) and (7) were cured sequentially at room temperature for 24 h, at 70 ℃ for 2 h, and at 120 ℃ for 4 h. After curing, performance tests were performed. The relevant test results are shown in Table 1. Figure 2 , Figure 3 and Figure 4 As shown.

[0061] Example 3 (1) 2.0 g of BNO prepared in Example 1 was added to 140 ml of ethanol solution and ultrasonically dispersed for 0.5 h. Then, 20 ml of Tris buffer was added to the above mixed solution and ultrasonically dispersed for 1.5 h. Next, 2.0 g of dopamine hydrochloride was added to the above mixed solution and stirred at 60 °C for 8 h to obtain a mixed solution of hydroxylated boron nitride with polydopamine surface polymerized. 2.0 g of phytic acid, 1.0 g of melamine and 1.0 g of cerium nitrate hexahydrate were dispersed in 40 mL of deionized water and stirred at 25 °C for 0.5 h to form PMC. Subsequently, PMC was added to the above mixed solution of hydroxylated boron nitride with polydopamine surface polymerized, and stirring was continued at room temperature for 16 h. The resulting product was centrifuged at 4000 rpm for 10 min, and the precipitate was washed three times with ethanol-water solution. The product was vacuum dried at 60 °C for 12 h to obtain BNO@PDA / PMC powder.

[0062] (2) Place 100 g of deionized water and 1 g of BNO@PDA / PMC powder in a beaker and sonicate to obtain BNO@PDA / PMC dispersion 1.

[0063] (3) Place 100 g of deionized water and 5 g of BNO@PDA / PMC in a beaker and sonicate to obtain BNO@PDA / PMC dispersion 2.

[0064] (4) Place 100 g of waterborne epoxy resin, 100 g of BNO@PDA / PMC dispersion 1, 0.24 g of BYK-333 leveling agent, 0.24 g of BYK-066N defoamer, 0.24 g of BYK-P104 dispersant and 0.24 g of BYK-410 antisettling agent in a paint tank and disperse them evenly by vibration using a high-speed disperser to obtain epoxy resin component 5; 100 g of waterborne epoxy resin, 100 g of BNO@PDA / PMC dispersion 2, 0.24 g of BYK-333 leveling agent, 0.24 g of BYK-066N defoamer, 0.24 g of BYK-P104 dispersant and 0.24 g of BYK-410 anti-settling agent were placed in a paint tank and dispersed evenly by vibration using a high-speed disperser to obtain epoxy resin component 6.

[0065] (5) Add 25 parts by weight of water-based polyamide curing agent to each of the steps (4), and disperse them evenly by high-speed dispersion to obtain coating 5 and coating 6.

[0066] (6) The coating 5 obtained in step (5) is applied to the steel plate using a wire bar coater to prepare coating sample 3. The steel plate used for testing corrosion resistance is coated with a thickness of about 60 μm.

[0067] (7) Pour the coating 6 obtained in step (5) into a preheated mold to prepare flame retardant test specimen 3.

[0068] (8) The samples obtained in steps (6) and (7) were cured sequentially at room temperature for 24 h, at 70 ℃ for 2 h, and at 120 ℃ for 4 h. After curing, performance tests were performed. The relevant test results are shown in Table 1. Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown.

[0069] Depend on Figure 2 The infrared spectrum clearly shows that the infrared spectrum of the coating in Example 1 is at 3200 cm⁻¹. -1 The presence of a BOH peak indicates that the boron nitride surface is hydroxylated; the infrared spectrum of the coating in Example 2 is at 1041 cm⁻¹. -1 The presence of a BOC peak at this location indicates that polydopamine has polymerized on the surface of the hydroxylated boron nitride, and the disappearance of the original BOH peak further indicates that the surface is covered; the infrared spectrum of the coating in Example 3 is at 3168 cm⁻¹. -1 Contains NH3 + The peak is at 1024 cm. -1 The presence of a PO peak indicates the formation of phytic acid supramolecular modified boron nitride.

[0070] Figure 3 X-ray photoelectron spectroscopy (XPS) results for BNO@PDA / PMC composite materials. Full spectrum scan results ( Figure 3 Characteristic signal peaks for Ce and P elements can be observed in a). Further analysis of the high-resolution spectrum... Figure 3 The P2p spectrum of b confirms the presence of phosphate groups in the phytic acid molecule. Figure 3 The Ce 3d spectrum of c shows the characteristic orbital binding energy of Ce, confirming that it is Ce-oriented. 3+ The chemical state of these substances exists within the supramolecular structure. These results collectively verify that the supramolecular network composed of phytic acid, melamine, and cerium ions has been successfully constructed through interfacial interactions.

[0071] Figure 4Transmission electron microscopy (TEM) and elemental plane distribution analysis revealed the morphological characteristics of boron nitride nanosheets. As shown in the figure, C, N, O, P, and Ce elements are uniformly distributed on the BNO@PDA composite structure. This result confirms that phytic acid supramolecular (PMC) has achieved self-assembly on the surface of boron nitride nanosheets through the bridging effect of polydopamine (PDA).

[0072] Figure 5 The Tafel polarization curves of each coating sample in typical corrosive media are shown. As the characterization results show, the corrosion potentials of EP, EP-BNO, EP-BNO@PDA, and EP-BNO@PDA / PMC are -0.485 V, -0.294 V, -0.177 V, and -0.138 V, respectively, showing a progressively positive shift. Among them, EP-BNO@PDA / PMC has the highest corrosion potential, indicating that it has the lowest thermodynamic corrosion tendency and the best protective performance. This trend is closely related to the labyrinth barrier effect of BNO in the coating, the improved interfacial compatibility of PDA, and the metal passivation and corrosion inhibition provided by the PMC self-assembled layer, proving that the multilayer modification strategy can synergistically improve the corrosion resistance of the coating.

[0073] Example 4 The difference between Example 3 and Example 4 is that the calcination temperature and time are different in the BNO preparation process; the rest of the process is the same as in Example 3. Details are shown in Table 1 below: Table 1. Changes in parameters in Example 4

[0074] Example 5 The difference from Example 3 lies in the reaction temperature and time of the mixed solution of hydroxylated boron nitride with polydopamine polymerized on its surface; the rest of the process is the same as in Example 3. Details are shown in Table 2 below: Table 2 Temperature and time variations in Example 5

[0075] The difference from Example 3 is that the raw material ratio for preparing the mixed solution of hydroxylated boron nitride with polydopamine polymerized on its surface is different; the rest of the process is the same as in Example 3. Details are shown in Table 3 below: Table 3. Changes in raw material ratios in Example 5

[0076] Example 6 The difference from Example 3 is that the amount of phytic acid supramolecular modified boron nitride dispersion used is 80g, while the rest of the process is the same as in Example 3.

[0077] Example 7 The difference from Example 3 is that the amount of phytic acid supramolecular modified boron nitride dispersion used is 120g, while the rest of the process is the same as in Example 3.

[0078] Comparative Example 1 (1) Place 100 g of waterborne epoxy resin, 100 g of deionized water, 0.24 g of BYK-333 leveling agent, 0.24 g of BYK-066N defoamer, 0.24 g of BYK-P104 dispersant and 0.24 g of BYK-410 antisettling agent in a paint tank and disperse them evenly by vibrating with a high-speed disperser.

[0079] (2) Add 25 g of water-based polyamide curing agent to step (1), and disperse it evenly by high-speed dispersion to obtain coating.

[0080] (3) The coating obtained in step (2) is applied to the steel plate using a wire bar coater to prepare a coating sample. The steel plate used for testing corrosion resistance is coated with a thickness of about 60 μm.

[0081] (4) Pour the coating obtained in step (2) into a preheated mold to prepare flame-retardant test specimens.

[0082] (5) The samples obtained in steps (3) and (4) were cured sequentially at room temperature for 24 h, at 70 ℃ for 2 h, and at 120 ℃ for 4 h. After curing, performance tests were performed. The relevant test results are shown in Table 1 and... Figure 5 As shown.

[0083] Test Example 1 Test procedure / conditions: (1) Salt spray test: The coating samples were tested in a Q-Lab salt spray chamber according to the GB6458-86 test standard. A 5.0 wt% NaCl solution with pH=6.5-7.0 and a temperature of 35℃ was continuously sprayed onto the samples to simulate the acidic and humid environment of the ocean. Before the test, the coating surface needed to be scratched to achieve the test results. At the same time, the back and edges of the steel plate were sealed to prevent salt spray from penetrating into the coating along the edges, thus affecting the accuracy of the test. The protective effect of the coating was evaluated by observing the corrosion of the coating samples. The test duration was 60 days.

[0084] (2) Impedance Testing: Electrochemical data (EIS) of the coating were obtained using a Metrohm Autolab 302N electrochemical workstation. A cross-section of 19.6 cm⁻¹ was used. 2An electrolytic cell was fabricated on the coated surface of an acrylic tube, containing a 3.5 wt% NaCl solution, with the total solution volume exceeding 60% of the tube's volume. A three-electrode system was primarily used for testing: a steel plate, an Ag / AgCl plate, and a platinum sheet served as the working electrode, reference electrode, and counter electrode, respectively. The testing frequency ranged from 100 kHz to 0.01 Hz, with an amplitude of 20 mV. To avoid errors and randomness, all measurements were performed on at least three samples, with the median value taken from multiple measurements. EIS data were fitted and analyzed using ZSimpWin software.

[0085] (3) Vertical burning test (UL-94) According to GB / T2408-2008, the test sample (125 mm × 12.5 mm × 3.5 mm) was tested in an FTT 0082 vertical combustion tester.

[0086] (4) Limiting Oxygen Index (LOI) According to ASTM-D 2863 standard, the sample (100 mm × 6 mm × 3.5 mm) was tested using an FTT 0077 oxygen index meter in a mixture of nitrogen and air.

[0087] The coating samples prepared in Examples and Comparative Example 1 were subjected to corrosion resistance tests according to the methods described above; the flame retardant test strips prepared in Examples and Comparative Example 1 were subjected to flame retardancy tests.

[0088] The relevant test results are shown in Table 4.

[0089] Table 4 Corrosion and flame retardant properties of phytic acid supramolecular modified boron nitride coatings

[0090] The data in Table 4 show that the introduction of boron nitride modification effectively enhances the protective performance of the coating. Compared with Comparative Example 1, Example 1 (addition of hydroxylated boron nitride) shows a preliminary enhancement in salt spray resistance and impedance; Example 2 (hydroxylated boron nitride@polydopamine) shows a significant enhancement in impedance performance; while Example 3 (phytic acid supramolecular modified boron nitride) exhibits the best performance, displaying the highest coating impedance.

[0091] Table 4 shows that the introduction of boron nitride-based modified components effectively improved the flame retardancy of the material. Specifically: First, compared with Comparative Example 1 (without added boron nitride components), Example 1 (with added hydroxylated boron nitride) has shown preliminary effects; furthermore, Example 2 polymerized polydopamine on the surface of hydroxylated boron nitride, and through the synergistic effect of the two, the limiting oxygen index (LOI) was further increased by 3%; finally, the phytic acid supramolecular modification strategy used in Example 3 exhibited the best performance, achieving the highest V-0 rating in UL-94, and the LOI was significantly improved by 8% compared with Comparative Example 1.

[0092] As can be seen from the data in Table 4, the increase in the number of components in the phytic acid supramolecular modified boron nitride dispersion increases both the corrosion resistance and flame retardancy of the prepared coating.

[0093] The method of this invention has been described through preferred embodiments. Those skilled in the art will readily be able to modify or appropriately alter and combine the methods and applications described herein within the scope, spirit, and context of this invention to implement and apply the technology of this invention. Those skilled in the art can refer to the content herein to appropriately improve process parameters. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the scope of this invention.

Claims

1. A phytic acid supramolecular modified boron nitride bifunctional coating composition characterized in that, The coating composition comprises a base resin, a phytic acid supermolecule modified boron nitride dispersion liquid, a functional additive, and a curing agent. The phytic acid supermolecule modified boron nitride dispersion liquid contains hydroxylated boron nitride with polydopamine polymerized on the surface and phytic acid supermolecule. The structural formula of the polydopamine-hydroxylated boron nitride is: (I); The structural formula of the phytic acid supermolecule is (II).

2. The coating composition of claim 1, wherein, impedance ≥ 3.83 x 10 8 Ω·cm 2 or, impedance ≥ 4 x 10 8 Ω·cm 2 or, impedance ≥ 5 x 10 8 Ω·cm 2 or, impedance ≥ 5.5 x 10 8 Ω·cm 2 ; The limiting oxygen index of the coating composition is greater than or equal to 25%, or greater than or equal to 27%.

3. The coating composition of claim 1, wherein The phytic acid supermolecule is an aggregate formed by coordination of phytic acid, melamine, and cerium nitrate hexahydrate stirred in deionized water. The mass ratio of the phytic acid, melamine, and cerium nitrate hexahydrate is (2-2.5):(1-1.5):(1-1.5). The coordination reaction is carried out at 15-35°C for 20-40 min.

4. The coating composition of claim 1, wherein The hydroxylated boron nitride with polydopamine polymerized on the surface is obtained by stirring and polymerizing hydroxylated boron nitride and dopamine in Tris buffer solution. The Tris buffer solution is Tris buffer solution with a pH of 8.

5. The hydroxylated boron nitride with polydopamine polymerized on the surface is prepared by dispersing hydroxylated boron nitride in ethanol to obtain a mixed solution, adding Tris buffer solution to disperse uniformly, adding hydrochloric acid dopamine, and reacting at 55-65°C for 6-8 h to complete polymerization. The mass ratio of the mixed solution and the Tris buffer solution is (5-10):

1. The mass ratio of the hydroxylated boron nitride and the hydrochloric acid dopamine is (1-2):(1-2). The hydroxylated boron nitride is ultrasonically dispersed in ethanol for 20-40 min. After adding the Tris buffer solution, ultrasonic dispersion is carried out for 20-40 min. The polymerization reaction is carried out at 60°C for 8 h.

5. The coating composition of claim 4, wherein The hydroxylated boron nitride is obtained by calcining boron nitride and deionized water under a nitrogen atmosphere. The calcination temperature is 850-950°C, and the holding time is 10-120 min.

6. The coating composition of claim 1, wherein The coating composition comprises a base resin, a phytic acid supermolecule modified boron nitride dispersion liquid, a functional additive, and a curing agent. The base resin is at least one selected from water-based epoxy resin, silicone resin, acrylic resin, polyurethane resin, polyester resin, and alkyd resin. The curing agent is at least one selected from diamine-based diphenyl methane, polyamide, diamino diphenyl sulfone, m-phenylenediamine, m-xylene diamine, and polyether amine. The functional additive includes at least one of leveling agent, defoaming agent, dispersant, and anti-settling agent. The functional additive includes at least one of BYK-333 leveling agent, BYK-066N defoaming agent, BYK-P104 dispersant, and BYK-410 anti-settling agent. The coating composition comprises, by weight fraction, 100 parts of base resin, 80-120 parts of phytic acid supermolecule modified boron nitride dispersion liquid, 0.94 parts of functional additive, and 25 parts of curing agent. The mass concentration of the phytic acid supermolecule modified boron nitride dispersion liquid is 0.5-5%.

7. A method of preparing the phytic acid supermolecule modified boron nitride bifunctional coating composition according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: S1. Hydroxylated boron nitride is obtained by calcining boron nitride and deionized water under a nitrogen atmosphere. S2. A solution of hydroxylated boron nitride with polydopamine polymerized on the surface is obtained by stirring and polymerizing hydroxylated boron nitride and dopamine in Tris buffer solution. S3, the phytic acid, the melamine and the cerium nitrate hexahydrate are stirred in the deionized water to assemble the aggregate phytic acid supramolecular solution by coordination; S4, the solution of the hydroxylated boron nitride polymerized with the polydopamine and the solution of the phytic acid supramolecular are mixed to react completely, and then the phytic acid supramolecular modified boron nitride powder is prepared by centrifugation, washing and drying; S5, the phytic acid supramolecular modified boron nitride powder is dissolved in the deionized water to prepare a phytic acid supramolecular modified boron nitride dispersion liquid; S6, the base resin, the phytic acid supramolecular modified boron nitride dispersion liquid, the functional additive and the curing agent are uniformly dispersed by a high-speed dispersion machine to obtain an epoxy resin component; S7, the epoxy resin component and the curing agent are uniformly dispersed by a high-speed dispersion machine to obtain a coating composition.

8. The preparation method according to claim 7, characterized in that, In S1, the calcination temperature is 850-950 ℃, and the holding time of the calcination is 10-120 min; Or, in S2, the hydroxylated boron nitride is dispersed in ethanol to obtain a mixed solution, the Tris buffer solution is added and uniformly dispersed, the dopamine hydrochloride is added, and the reaction is carried out at 55-65 ℃ for 6-8 h, and then the product is obtained by centrifugation, washing and drying after the polymerization is completed; Or, in S3, the mass ratio of the phytic acid, the melamine and the cerium nitrate hexahydrate is (2-2.5):(1-1.5):(1-1.5), and the coordination reaction is carried out at 15-35 ℃ for 20-40 min; Or, the mass ratio of the phytic acid and the hydroxylated boron nitride is (1-2):(1-2).

9. The preparation method according to claim 7, characterized in that, In S4, the mixing reaction is carried out at 15-35 ℃ for 12-16 h, or the centrifugation is 4000 rpm for 10 min, or the drying is vacuum drying at 60 ℃ for 12 h, or the washing is washing with an ethanol aqueous solution.

10. The preparation method according to claim 7, characterized in that, The coating composition comprises, by weight fraction, 100 parts of the base resin, 80-120 parts of the phytic acid supramolecular modified boron nitride dispersion liquid, 0.94 parts of the functional additive and 25 parts of the curing agent; or the mass concentration of the phytic acid supramolecular modified boron nitride dispersion liquid is 0.5-5%; Or, in S6, the uniform dispersion time is 1-2 h, and the stirring speed of the dispersion is 1500-2000 r / min; Or, in S7, the uniform dispersion time is 1-2 h, and the stirring speed of the dispersion is 1500-2000 r / min.

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