A phosphorus-containing aniline oligomer-modified boron nitride fire-retardant and anti-corrosion dual-function coating composition and its preparation method

Abstract

This invention discloses a fire-retardant and corrosion-resistant dual-function coating composition of aniline oligomer containing phosphorus and nitrogen, and its preparation method. The composition comprises a base resin, a modified boron nitride dispersion, an intumescent flame-retardant system, functional additives, and a curing agent. The modified boron nitride dispersion includes ammonium dihydrogen phosphate-terminated aniline oligomers, boron nitride, and a dispersion medium. This invention provides a modified boron nitride composite coating with both fire-retardant and corrosion-resistant functions. It achieves high-efficiency corrosion protection by blocking corrosive media through the labyrinth effect of the two-dimensional material boron nitride and the passivation and trapping effects of the aniline oligomers and ammonium dihydrogen phosphate; and fire resistance is achieved through the combustion of non-flammable gases from the aniline oligomers and the catalytic carbonization of polyphosphoric acid by ammonium dihydrogen phosphate. The ammonium dihydrogen phosphate-terminated aniline oligomers in this invention enhance the compatibility of boron nitride in the base resin through π-π conjugation, effectively improving the product's fire resistance limit and corrosion resistance, thereby extending the service life of the organic coating.

Description

Technical Field

[0001] This invention belongs to the field of fireproof and anticorrosive coating technology, specifically relating to a dual-function fireproof and anticorrosive coating composition of phosphorus-nitrogen aniline oligomer modified boron nitride and its preparation method. Background Technology

[0002] The rapid development of industries such as marine transportation, marine engineering, new energy development, and new chemical materials has placed higher demands on coatings for offshore equipment such as offshore oil platforms and near-shore steel structures. These coatings not only need excellent corrosion resistance but also good fire resistance. However, existing steel structure coatings typically only offer one function: fire-retardant or anti-corrosion coatings. While coatings with both fire-retardant and anti-corrosion properties exist, their application processes are often cumbersome and costly, and poor compatibility can lead to peeling, thus affecting the protective effect. Therefore, developing a dual-function fire-retardant coating that combines corrosion resistance and fire resistance, achieving an integrated design of corrosion protection and protection, can solve the problems of cumbersome processes associated with mixing fire-retardant and anti-corrosion coatings.

[0003] Nanomaterials, a newly emerging and highly regarded discipline that has only been around for a decade or so, has seen its application in the coatings field become a research hotspot. In particular, the application of nanotechnology to achieve halogen-free flame retardants and fillers is of great significance for the development of ultra-thin fire-resistant and corrosion-resistant coatings for steel structures. Boron nitride nanosheets, due to their unique two-dimensional structure, show promising applications in fire and corrosion protection. However, due to their high surface energy and large volume, boron nitride nanosheets tend to aggregate in resin matrices, which limits their application in fire-resistant and corrosion-resistant coatings. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a dual-function coating composition of phosphorus-nitrogen aniline oligomer modified boron nitride for fire resistance and corrosion protection.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned phosphorus-nitrogen aniline oligomer modified boron nitride fire-retardant and anti-corrosion dual-function coating composition.

[0006] The technical solution of the present invention is as follows:

[0007] A phosphorus-nitrogen aniline oligomer-modified boron nitride fire-retardant and corrosion-resistant dual-function coating composition is prepared from a base resin, a modified boron nitride dispersion, an intumescent flame-retardant system, functional additives, and a curing agent.

[0008] The modified boron nitride in this modified boron nitride dispersion has the following structural formula:

[0009]

[0010] In a preferred embodiment of the present invention, the modified boron nitride dispersion is prepared by dispersing ammonium dihydrogen phosphate-terminated aniline oligomers and boron nitride in deionized water; the ammonium dihydrogen phosphate-terminated aniline oligomers are prepared by doping aniline oligomers with ammonium dihydrogen phosphate through protonation; and the aniline oligomers are prepared by aniline and p-phenylenediamine sulfate under acidic conditions.

[0011] More preferably, the preparation method of the modified boron nitride dispersion includes the following steps:

[0012] A. Dissolve aniline and p-phenylenediamine sulfate in a dilute solution of ammonium dihydrogen phosphate;

[0013] B. After dissolving ammonium persulfate (APS) in a dilute solution of ammonium dihydrogen phosphate, add it dropwise to the material obtained in step A at a rate of 2-4 seconds per drop while stirring. After the addition is complete, continue stirring at the same rate for 0.8-1.2 hours to obtain a precipitate. After solid-liquid separation and drying, the ammonium dihydrogen phosphate-terminated aniline oligomer is obtained.

[0014] C. The boron nitride and the above-mentioned ammonium dihydrogen phosphate-terminated aniline oligomer were ultrasonically dispersed in a dispersion medium for 2-4 hours. Then, the two were mixed and stirred at room temperature for 4-8 hours to fully react, resulting in a modified boron nitride dispersion.

[0015] More preferably, in the dilute ammonium dihydrogen phosphate solution, the ratio of ammonium dihydrogen phosphate to deionized water is 1.1-1.2 g: 230-260 mL, and the mass ratio of boron nitride to the ammonium dihydrogen phosphate-terminated aniline oligomer is 1:1-3.

[0016] More preferably, the stirring speed in step C is 400-600 r / min.

[0017] In a preferred embodiment of the present invention, the matrix resin is selected from waterborne epoxy resin, silicone resin, acrylic resin, polyurethane resin, polyester resin, and alkyd resin; the curing agent is selected from diaminodiphenylmethane, polyamide, diaminodiphenyl sulfone, m-phenylenediamine, m-phenylenediamine, and polyetheramine.

[0018] More preferably, in the intumescent flame retardant system, APP:MEL:PER = 2:1:1 (APP is ammonium polyphosphate, MEL is melamine, and PER is pentaerythritol).

[0019] More preferably, the functional additives include leveling agents, defoamers, dispersants, and anti-settling agents.

[0020] The preparation method of the above-mentioned phosphorus-containing aniline oligomer-modified boron nitride fire-retardant and anti-corrosion dual-function coating composition includes the following steps:

[0021] (1) Stir and disperse the matrix resin, modified boron nitride dispersion, intumescent flame retardant system and functional additives for 1-2 hours;

[0022] (2) Add the curing agent to the material obtained in step (1) and stir and disperse for 1-2 hours to obtain the product.

[0023] In a preferred embodiment of the present invention, the stirring speed in steps (1) and (2) is 1500-2000 r / min.

[0024] The beneficial effects of this invention are:

[0025] 1. The phosphate-terminated aniline oligomer in this invention has the functions of passivating metal surfaces, "capturing" iron ions, and promoting the formation of complexes, thus inhibiting corrosion. In addition, the aniline oligomer has a high nitrogen content, which will produce a large amount of non-combustible gases such as NO and NO2 during combustion, diluting the oxygen concentration and playing a role in gas-phase flame retardancy.

[0026] 2. The ammonium dihydrogen phosphate in this invention will eventually produce polyphosphoric acid during combustion, which will catalyze the formation of carbon and achieve excellent flame retardant properties.

[0027] 3. The boron nitride two-dimensional material in this invention forms a labyrinth effect due to its large specific surface area, which effectively prevents the diffusion of corrosive agents. It is also chemically stable, heat resistant, and can form the skeleton of the protective system of the residual carbon layer during combustion, effectively preventing the coating from cracking under flame and improving the product's corrosion resistance and fire resistance limit.

[0028] 4. The ammonium dihydrogen phosphate-terminated aniline oligomer-modified boron nitride in this invention is modified by π-π conjugated non-covalent bonds to obtain N,P-modified boron nitride nanosheets, which greatly enhances the compatibility of boron nitride inorganic materials in organic resins, thereby effectively extending the service life of the coating.

[0029] 5. This invention develops a composite ternary expansion system that comprehensively applies flame retardant-smoke suppression synergistic flame retardant technology, including phosphorus, nitrogen, boron nitride, and inorganic flame retardants, as well as halogen-free flame retardant technology, to improve the product's fire resistance limit and further endow the product with environmental protection significance. Attached Figure Description

[0030] Figure 1 This is a schematic diagram illustrating the preparation process of ammonium dihydrogen phosphate-terminated aniline oligomer (AT-P) and modified boron nitride (BN-AT-P) in Examples 1 to 4 of the present invention.

[0031] Figure 2 The infrared spectra of aniline oligomer (AT), ammonium dihydrogen phosphate-terminated aniline oligomer (AT-P), and modified boron nitride (BN-AT-P) in Examples 1 to 4 of this invention are shown.

[0032] Figure 3 This is a comparison chart showing the temperature change over time on the back of the coated steel plate in Comparative Example 1 and Examples 1 to 4 of the present invention.

[0033] Figure 4 These are macroscopic morphology diagrams of the expanded carbon layer of the matrix resin in Comparative Example 1 and Examples 1 to 4 of the present invention. Detailed Implementation

[0034] The technical solution of the present invention will be further explained and described below with reference to specific embodiments and accompanying drawings.

[0035] Comparative Example 1

[0036] (1) Place 100 parts by weight of waterborne epoxy resin, 80 parts by weight of intumescent flame retardant system (APP:MEL:PER=2:1:1), 0.24 parts by weight of BYK-066N type defoamer, 0.24 parts by weight of BYK-P104 type dispersant and 0.24 parts by weight of BYK-410 type anti-settling agent into a paint tank and disperse them evenly by vibration using a high-speed disperser.

[0037] (2) Add 100 parts by weight of polyamide curing agent to step (1), and disperse evenly by high-speed disperser to obtain coating APP / MEL / PER.

[0038] (3) The material obtained in step (2) is coated onto 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, and the steel plate used for testing fire resistance is coated with a thickness of about 1 mm.

[0039] (4) Pour the material obtained in step (2) into a preheated mold to prepare flame-retardant test specimens, and cure them at room temperature for 24 hours, at 70°C for 2 hours, and at 120°C for 4 hours.

[0040] (5) After curing, the samples obtained in steps (3) and (4) are subjected to performance tests. The relevant test results are shown in Table 1 and... Figure 3 , Figure 4 As shown.

[0041] Example 1

[0042] (1) Weigh 1.15 g of ammonium dihydrogen phosphate and dilute it with deionized water to obtain 250 mL of dilute ammonium dihydrogen phosphate solution. Measure 150 mL of the dilute ammonium dihydrogen phosphate solution into a 250 mL round-bottom flask. Weigh 2.956 g of p-phenylenediamine sulfate and add it to the flask for ultrasonic dispersion. After the p-phenylenediamine sulfate is completely dissolved, weigh 1.853 g of aniline and add it to the flask. At the same time, weigh 4.541 g of ammonium persulfate (APS) and dissolve it in 50 mL of dilute ammonium dihydrogen phosphate solution, then add it to a constant-pressure dropping funnel. Place the flask in a low-temperature circulating tank at -5℃ and slowly add the solution to the flask at a rate of 3 drops / second, while stirring. After the addition is complete, continue stirring for 1 hour. After the reaction is complete, filter the product and wash it with deionized water until the filtrate is neutral to obtain a filter cake. The filter cake was placed in a vacuum oven and dried at 60°C for 24 hours. The resulting product was then ball-milled using a planetary ball mill to obtain the infrared spectrum shown below. Figure 2 The ammonium dihydrogen phosphate-terminated aniline oligomer shown is AT-P;

[0043] (2) Weigh 100 mg of boron nitride and 200 mg of ammonium dihydrogen phosphate-terminated aniline oligomer and add them to 25 mL of deionized water. Sonicate for 1 h to obtain a modified boron nitride dispersion. (The preparation principles of steps (1) and (2) above are as follows...) Figure 1 As shown, the infrared spectrum of this modified boron nitride is as follows: Figure 2 (As shown)

[0044] (3) Place 100 parts by weight of waterborne epoxy resin, 0.5 parts by weight of the above-mentioned ammonium dihydrogen phosphate-terminated aniline oligomer modified boron nitride, 80 parts by weight of the intumescent flame retardant system (APP:MEL:PER=2:1:1), 0.24 parts by weight of BYK-066N type defoamer, 0.24 parts by weight of BYK-P104 type dispersant and 0.24 parts by weight of BYK-410 type anti-settling agent into a paint tank and disperse them evenly by vibration using a high-speed disperser.

[0045] (4) Add 100 parts by weight of polyamide curing agent to the material obtained in step (3), and disperse it evenly by high-speed disperser to obtain coating APP / MEL / PER-0.5%BAP.

[0046] (5) The material obtained in step (4) is coated onto 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, and the steel plate used for testing fire resistance is coated with a thickness of about 1 mm.

[0047] (6) Pour the material obtained in step (4) into a preheated mold to prepare flame-retardant test specimens, and cure them at room temperature for 24 hours, at 70°C for 2 hours, and at 120°C for 4 hours.

[0048] (7) After curing, the samples obtained in steps (5) and (6) are subjected to performance tests. The relevant test results are shown in Table 1 and... Figure 3 , Figure 4 As shown.

[0049] Example 2

[0050] Steps (1) and (2) are the same as in Example 1.

[0051] (3) Place 100 parts by weight of waterborne epoxy resin, 1 part by weight of the above-mentioned ammonium dihydrogen phosphate-terminated aniline oligomer modified boron nitride, 80 parts by weight of the intumescent flame retardant system (APP:MEL:PER=2:1:1), 0.24 parts by weight of BYK-333 leveling agent, 0.24 parts by weight of BYK-066N defoamer, 0.24 parts by weight of BYK-P104 dispersant and 0.24 parts by weight of BYK-410 anti-settling agent in a paint tank and disperse them evenly by vibration using a high-speed disperser.

[0052] (4) Add 100 parts by weight of polyamide curing agent to the material obtained in step (3), and disperse it evenly by high-speed disperser to obtain coating APP / MEL / PER-1%BAP.

[0053] Steps (5) to (7) are the same as in Example 1.

[0054] The relevant test results are shown in Table 1 and Figure 3 , Figure 4 As shown.

[0055] Example 3

[0056] Steps (1) and (2) are the same as in Example 1.

[0057] (3) Place 100 parts by weight of waterborne epoxy resin, 1.5 parts by weight of the above-mentioned ammonium dihydrogen phosphate-terminated aniline oligomer modified boron nitride, 80 parts by weight of the intumescent flame retardant system (APP:MEL:PER=2:1:1), 0.24 parts by weight of BYK-066N type defoamer, 0.24 parts by weight of BYK-P104 type dispersant and 0.24 parts by weight of BYK-410 type anti-settling agent into a paint tank and disperse them evenly by vibration using a high-speed disperser.

[0058] (4) Add 100 parts by weight of polyamide curing agent to the material obtained in step (3), and disperse it evenly by high-speed disperser to obtain coating APP / MEL / PER-1.5%BAP.

[0059] Steps (5) to (7) are the same as in Example 1.

[0060] The relevant test results are shown in Table 1 and Figure 3, Figure 4 As shown.

[0061] Example 4

[0062] Steps (1) and (2) are the same as in Example 1.

[0063] (3) Place 100 parts by weight of waterborne epoxy resin, 2 parts by weight of the above-mentioned ammonium dihydrogen phosphate-terminated aniline oligomer modified boron nitride, 80 parts by weight of the intumescent flame retardant system (APP:MEL:PER=2:1:1), 0.24 parts by weight of BYK-066N type defoamer, 0.24 parts by weight of BYK-P104 type dispersant and 0.24 parts by weight of BYK-410 type anti-settling agent into a paint tank and disperse them evenly by vibration using a high-speed disperser.

[0064] (4) Add 100 parts by weight of polyamide curing agent to the material obtained in step (3), and disperse it evenly by high-speed disperser to obtain coating APP / MEL / PER-2%BAP.

[0065] Steps (5) to (7) are the same as in Example 1.

[0066] The relevant test results are shown in Table 1 and Figure 3 , Figure 4 As shown.

[0067] Table 1. Fire and corrosion resistance of boron nitride coatings modified with ammonium dihydrogen phosphate-terminated aniline oligomers.

[0068]

[0069] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A phosphorus-nitrogen aniline oligomer-modified boron nitride fire-retardant and anti-corrosion dual-function coating composition, characterized in that: It is prepared from water-based epoxy resin, modified boron nitride dispersion, intumescent flame retardant system, functional additives, and curing agent. The modified boron nitride in the modified boron nitride dispersion has the following structural formula: The amount of modified boron nitride added is 1-2 wt% of the waterborne epoxy resin. The curing agent is selected from diaminodiphenylmethane, polyamide, diaminodiphenyl sulfone, m-phenylenediamine, m-phenylenediamine and polyetheramine.

2. The phosphorus-containing aniline oligomer-modified boron nitride fire-retardant and anti-corrosion dual-function coating composition as described in claim 1, characterized in that: The modified boron nitride dispersion is prepared by dispersing ammonium dihydrogen phosphate-terminated aniline oligomers and boron nitride in deionized water; the ammonium dihydrogen phosphate-terminated aniline oligomers are prepared by doping aniline oligomers with ammonium dihydrogen phosphate through protonation; the aniline oligomers are prepared by aniline and p-phenylenediamine sulfate under acidic conditions.

3. The phosphorus-containing aniline oligomer-modified boron nitride fire-retardant and anti-corrosion dual-function coating composition as described in claim 2, characterized in that: The preparation method of the modified boron nitride dispersion includes the following steps: A. Dissolve aniline and p-phenylenediamine sulfate in a dilute solution of ammonium dihydrogen phosphate; B. After dissolving ammonium persulfate in a dilute solution of ammonium dihydrogen phosphate, add it dropwise to the material obtained in step A at a rate of 2-4 seconds per drop while stirring. After the addition is complete, continue stirring at the same rate for 0.8-1.2 hours to obtain a precipitate. After solid-liquid separation and drying, the ammonium dihydrogen phosphate-terminated aniline oligomer is obtained. C. The boron nitride and the above-mentioned ammonium dihydrogen phosphate-terminated aniline oligomer were ultrasonically dispersed in a dispersion medium for 2-4 hours. Then, the two were mixed and stirred at room temperature for 4-8 hours to fully react, resulting in a modified boron nitride dispersion.

4. The phosphorus-containing aniline oligomer-modified boron nitride fire-retardant and anti-corrosion dual-function coating composition as described in claim 3, characterized in that: In the dilute ammonium dihydrogen phosphate solution, the ratio of ammonium dihydrogen phosphate to deionized water is 1.1-1.2 g: 230-260 mL, and the mass ratio of boron nitride to the ammonium dihydrogen phosphate-terminated aniline oligomer is 1:1-3.

5. The phosphorus-containing aniline oligomer-modified boron nitride fire-retardant and anti-corrosion dual-function coating composition as described in claim 3, characterized in that: The stirring speed in step C is 400-600 r / min.

6. A phosphorus-containing aniline oligomer-modified boron nitride fire-retardant and anti-corrosion dual-function coating composition according to any one of claims 1 to 5, characterized in that: In the intumescent flame retardant system, APP:MEL:PER = 2:1:

1.

7. A phosphorus-containing aniline oligomer-modified boron nitride fire-retardant and anti-corrosion dual-function coating composition according to any one of claims 1 to 5, characterized in that: The functional additives include leveling agents, defoamers, dispersants, and antisettling agents.

8. A method for preparing the phosphorus-containing nitrogen-aniline oligomer-modified boron nitride fire-retardant and anti-corrosion dual-functional coating composition according to any one of claims 1 to 7, characterized in that: Includes the following steps: (1) Stir and disperse the waterborne epoxy resin, modified boron nitride dispersion, intumescent flame retardant system and functional additives for 1-2 hours; (2) Add the curing agent to the material obtained in step (1) and stir and disperse for 1-2 hours to obtain the product.

9. The preparation method according to claim 8, characterized in that: The stirring speed in steps (1) and (2) is 1500-2000 r / min.

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