Special explosion-proof corrosion-resistant pressure vessel protection material and preparation method thereof

Abstract

The invention belongs to the technical field of protective coatings, and particularly relates to a special explosion-proof corrosion-resistant pressure vessel protective material and a preparation method thereof. The problem that high strength, high flame retardance and high corrosion resistance of a current protective material restrict one another at the same time is solved. Through an innovative functional complex design and a preparation process, synergistic improvement of the three is realized, firstly, tannic acid and borax are used for carrying out functional modification on halloysite nanotubes, and a TA-B-coated HNTs functional complex is prepared; then, mixing the complex with polyether diamine and diethyltoluenediamine, and carrying out vacuum defoaming to obtain mixed resin; and finally, respectively heating the isocyanate prepolymer and the mixed resin to specific temperatures, and carrying out high-pressure impact mixing and rapid reaction to form the protective material.

Description

Technical Field

[0001] This invention belongs to the field of protective coating technology, specifically relating to a special explosion-proof and corrosion-resistant pressure vessel protective material and its preparation method. Background Technology

[0002] Pressure vessels in chemical plants typically operate under high temperature and high pressure conditions, requiring coatings with high mechanical strength and good adhesion to ensure safe operation, as well as good corrosion resistance to resist acid and alkali erosion.

[0003] However, commonly used high-performance coating materials, while meeting strength and chemical resistance requirements, often suffer from flammability. Epoxy resins are widely used in anti-corrosion coatings (CN121338124A) due to their excellent mechanical strength, chemical resistance, and adhesion; however, they are themselves flammable organic polymers, easily igniting and rapidly releasing heat when exposed to fire, lacking inherent flame retardancy. Improving the flame retardancy of organic coatings usually requires the addition of flame retardants, but traditional flame retardant methods often result in trade-offs in performance: for example, adding high-filler inorganic flame-retardant fillers can provide some flame retardancy but significantly reduces the mechanical strength and adhesion of the coating; halogenated flame retardants, while effective, easily produce toxic and corrosive gases, failing to meet environmental protection requirements. Phosphorus and nitrogen-based flame retardants are relatively environmentally friendly, but their addition can affect the mechanical properties or water resistance of the cured product, making it difficult to balance strength and flame retardancy.

[0004] In recent years, the introduction of nanofunctional fillers has provided a new approach to balancing the performance of coating materials. For example, introducing functionalized halloysite nanotubes (HNTs) into epoxy resin matrices can promote char formation during combustion and improve flame retardant efficiency. However, ordinary HNTs lack active flame retardant and corrosion inhibition functions, and their role is more of a physical barrier. When the modification is insufficient, it is difficult to achieve significant flame retardant and corrosion-resistant effects. In addition to the challenges of flame retardancy, existing anti-corrosion coatings also have limitations in heavy-duty corrosion protection. Traditional high-efficiency anti-corrosion pigments and fillers often use inorganic corrosion inhibitors such as lead and chromates. Although they can provide certain cathodic protection or passivation, these substances are toxic and environmentally unfriendly, and their use is strictly limited. Phytochemical-based tannic acid (TA), due to its abundant phenolic hydroxyl groups, can complex with metal ions to form a stable protective film and is considered a promising green corrosion inhibitor. However, the direct mixing of small tannic acid molecules into the resin may result in uneven dispersion or poor compatibility with the resin, and it is easily dissolved and lost by water in the coating. Therefore, tannic acid needs to be loaded onto a suitable carrier or chemically bonded in order to exist stably in the coating and exert a long-term corrosion inhibition effect.

[0005] In summary, existing technologies still have significant shortcomings in simultaneously achieving high strength, flame retardancy, and corrosion resistance in coatings. There is an urgent need for a functional composite material that, by synergistically fixing tannic acid and boron-containing components onto nano-haloite, endows the coating material with efficient flame retardant and corrosion-resistant functions, while utilizing nanofillers to enhance mechanical strength, thus breaking through the bottleneck of balancing the performance of existing materials. Summary of the Invention

[0006] This invention provides a special explosion-proof and corrosion-resistant pressure vessel protective material and its preparation method, aiming to solve the problems of traditional epoxy and other matrix materials being flammable and having reduced mechanical properties after adding flame retardants, as well as the reliance on toxic corrosion inhibitors for corrosion protection.

[0007] The specific technical solution is as follows: A special explosion-proof and corrosion-resistant pressure vessel protective material and its preparation method are as follows: S1: Preparation of functional complexes.

[0008] S11: Halloysite nanotube powder was added to deionized water and ultrasonically treated to obtain an HNTs suspension.

[0009] S12: Tannic acid and borax are added sequentially to the HNTs suspension prepared in S11, stirred, and the pH is adjusted to 8.5-10. Then, the mixture is heated and stirred, centrifuged, washed, vacuum dried, ground and sieved to obtain the TA-B@HNTs functional complex.

[0010] S2: Preparation of mixed resin: preheat polyetheramine to 50-60℃, add diethyltoluenediamine, stir, then add the TA-B@HNTs functional composite prepared in S12, stir at medium speed first, then disperse by high-speed shearing, degas under vacuum, filter, and store under nitrogen to obtain mixed resin.

[0011] S3: Preparation of protective materials. The isocyanate prepolymer is heated to 58-62°C, and the mixed resin prepared in S2 is heated to 68-72°C. Then, the two are mixed under high pressure to obtain a protective coating.

[0012] Furthermore, the halloysite nanotube powder described in S11 has a mass-to-volume ratio of 1:20 g:mL with deionized water.

[0013] The ultrasonic treatment described in S11 has the following parameter settings: power 400-600W, frequency 20-25kHz, and duration 30-45min.

[0014] Furthermore, the tannic acid described in S12 has a mass ratio of 0.2:1 to 0.5:1 with halloysite nanotubes.

[0015] The borax described in S12 has a mass ratio of 0.05:1 to 0.15:1 with halloysite nanotubes.

[0016] The stirring described in S12 has the following parameters: rotation speed 300-500 rpm, duration 15-25 min.

[0017] The heating and stirring described in S12 has the following parameters: temperature 70-90℃, speed 400-600rpm, and duration 3-6h.

[0018] The vacuum drying described in S12 has the following parameters: temperature 60~80℃, vacuum degree -0.08~-0.09MPa, and duration 12~24h.

[0019] Furthermore, the stirring described in S2 has the following parameters: rotation speed 400-500 rpm, duration 15-30 min.

[0020] The medium-speed stirring described in S2 has the following parameters: rotation speed 500-800 rpm, duration 10-15 min.

[0021] The high-speed shear dispersion described in S2 has the following parameter settings: rotation speed 1000-1500 rpm, duration 40-60 min.

[0022] The vacuum degassing described in S2 has the following parameters: temperature 35℃, vacuum degree -0.08MPa, rotation speed 300rpm, and duration 30min.

[0023] The mixed resin described in S2 has the following composition of raw materials: based on 100 parts of polyetheramine, 15-40 parts of diethyltoluene diamine, and 3-10 parts of TA-B@HNTs.

[0024] Furthermore, the isocyanate prepolymer described in S3 has a -NCO mass fraction of 12% to 18% and a volume flow ratio of 1:1 with the mixed resin.

[0025] The high-pressure impact mixing described in S3 has the following parameter settings: system pressure 20-30 MPa, dynamic pressure 15-20 MPa, and static pressure 12-18 MPa.

[0026] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention achieves a synergistic flame retardant mechanism of "carbon source-acid source-skeleton" through the design of TA-B@HNTs functional composite filler.

[0027] 2. This invention combines the rigidity of HNTs with the flexibility of polyurea. The introduction of diethyltoluene diamine ensures that the material does not brittlely break under impact, while the TA-B coating ensures the effective transfer of stress at the interface. Attached Figure Description

[0028] Figure 1 This is a process flow diagram for the preparation of a special explosion-proof and corrosion-resistant pressure vessel protective material.

[0029] Figure 2 The Fourier transform infrared spectra are those of the unmodified HNTs in S11 and the TA-B@HNTs functional complex prepared in S12 in Example 1.

[0030] Figure 3 This is the Fourier transform infrared spectrum of the protective coating prepared in S3 of Example 1. Detailed Implementation

[0031] The following embodiments further explain and illustrate the technical solutions of the present invention. It should be specifically noted that each specific embodiment is a concretization and explanation of the technical solution and should not be considered as a limitation on the scope of protection of the present invention. Those skilled in the art still have the right to modify the technical solutions of these embodiments and make equivalent substitutions for some or all of the technical features, and these modifications or substitutions do not change the essence of the corresponding technical solutions, nor do they cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the present invention.

[0032] This invention proposes a special explosion-proof and corrosion-resistant pressure vessel protective material and its preparation method. Through the physical reinforcement of halloysite nanotubes, the chemical cross-linking and flame-retardant mechanism of the tannic acid-borax composite, and the microstructure optimization brought about by the high-pressure impact mixing process, a synergistic leap in the mechanical properties, flame-retardant properties, and corrosion resistance of the protective material is achieved. (See attached diagram) Figure 1 The diagram shows a method for preparing a special explosion-proof and corrosion-resistant pressure vessel protective material. The detailed technical solution is as follows: 1. Preparation of functional complexes Halloysite nanotube powder was added to deionized water and sonicated to obtain an HNTs suspension. Tannic acid and borax were added to the suspension in sequence, stirred, pH was adjusted, and then heated and stirred. The mixture was centrifuged, washed, vacuum dried, ground and sieved to obtain the TA-B@HNTs functional complex.

[0033] Tannic acid molecules contain abundant pyrogallol and catechol structures. Under alkaline and aerobic conditions, the phenolic hydroxyl groups are easily oxidized by dissolved oxygen to form quinone structures. These quinone structures react with each other to form a cross-linked polytannic acid network, which is deposited on the surface of HNTs. The silanol and aluminol hydroxyl groups on the surface of HNTs form strong hydrogen bonds with the phenolic hydroxyl groups in polytannic acid, and some undergo dehydration condensation to form covalent bonds, ensuring the firm adhesion of the modified layer. Borax hydrolyzes in aqueous solution to generate boric acid and borate ions. The borate ions can undergo a reversible esterification reaction with two adjacent phenolic hydroxyl groups in the tannic acid molecule to form dynamic borate ester bonds, promoting further cross-linking of the polytannic acid network, improving the density of the coating, and introducing boron element to provide excellent flame retardant properties.

[0034] 2. Preparation of mixed resins The polyetheramine was preheated and diethyltoluene diamine (DETDA) was added and stirred. Then, the TA-B@HNTs functional composite was added, stirred at medium speed first, then dispersed by high-speed shearing, vacuum degassing, and filtered to obtain a mixed resin.

[0035] The polar aromatic structure of diethyltoluene diamine forms hydrogen bonds with the ether oxygen atoms of the polyether segments. Since both the polyether amine and diethyltoluene diamine are liquids, they form a homogeneous solution upon mixing, eliminating the risk of phase separation. The surface of the TA-B@HNTs functional complex is rich in phenolic hydroxyl and quinone groups from tannic acid, forming multiple interactions with the amino and ether oxygen atoms in the amine monomers: strong hydrogen bonds are formed between the phenolic hydroxyl groups and the ether oxygen atoms of the polyether segments, and between the amino groups of DETDA; proton transfer occurs between the weakly acidic phenolic hydroxyl groups of tannic acid and the basic amino groups of the amines, achieving acid-base interactions; and π-π interactions exist between the aromatic rings of tannic acid and DETDA. These interfacial interactions promote the wetting and dispersion of the functional complex in the amine matrix, and lay the foundation for establishing a strong filler-matrix interfacial bond during subsequent reactions with isocyanates.

[0036] 3. Preparation of protective materials The isocyanate prepolymer is heated to 58–62°C, the mixed resin is heated to 68–72°C, and then the two are mixed under high pressure to obtain a protective coating.

[0037] Heating the isocyanate prepolymer to around 60°C reduces its viscosity, facilitating pumping and atomization, while preventing side reactions or thermal degradation caused by high temperatures. Heating the mixed resin to around 70°C ensures its viscosity is moderate, matching that of the isocyanate prepolymer, thus guaranteeing effective impact mixing. High-pressure impact mixing is employed to achieve homogeneous molecular-level mixing of both components in a very short time.

[0038] 4. Coating Application The impact-mixed material is sprayed from the nozzle of the spray gun to form an atomized jet, which is then coated onto the surface of the pretreated pressure vessel substrate. After curing (temperature 20-35℃, relative humidity ≤80%) for 14 days, it can be put into use.

[0039] Example 1 A method for preparing a special explosion-proof and corrosion-resistant pressure vessel protective material is as follows: Table 1 Main Raw Materials S1: Preparation of functional complexes.

[0040] S11: Halloysite nanotube powder was added to deionized water and ultrasonically treated to obtain an HNTs suspension. The mass-to-volume ratio of halloysite nanotube powder to deionized water was 1:20 g:mL. The ultrasonic treatment parameters were set as follows: power 500W, frequency 22.5kHz, and duration 38min.

[0041] S12: Tannic acid and borax were added sequentially to the HNTs suspension prepared in S11, stirred, and the pH was adjusted to 9. Then, the mixture was heated and stirred, centrifuged, washed, vacuum dried, ground, and sieved to obtain the TA-B@HNTs functional composite. The mass ratio of tannic acid to halloysite nanotubes was 0.35:1, and the mass ratio of borax to halloysite nanotubes was 0.1:1. The stirring parameters were set as follows: 400 rpm for 20 min; the heating and stirring parameters were set as follows: 80℃, 500 rpm for 4.5 h; and the vacuum drying parameters were set as follows: 70℃, -0.085 MPa, and 18 h.

[0042] S2: Preparation of mixed resin: 100g of polyetheramine was preheated to 55℃, 28g of diethyltoluene diamine was added, and the mixture was stirred. Then, 7g of the TA-B@HNTs functional composite prepared in S12 was added. The mixture was first stirred at medium speed, then dispersed by high-speed shearing, degassed under vacuum, filtered, and stored under nitrogen to obtain the mixed resin. The stirring parameters were set as follows: 450 rpm for 23 min; medium-speed stirring parameters were set as follows: 650 rpm for 13 min; high-speed shearing dispersion parameters were set as follows: 1250 rpm for 50 min; vacuum degassed parameters were set as follows: temperature 35℃, vacuum degree -0.08 MPa, 300 rpm for 30 min.

[0043] S3: Preparation of protective material. The isocyanate prepolymer is heated to 60°C, and the mixed resin prepared in S2 is heated to 70°C. Then, the two are subjected to high-pressure impact mixing to obtain a protective coating. The volume flow ratio of isocyanate prepolymer to mixed resin is 1:1. The high-pressure impact mixing parameters are set as follows: system pressure 25MPa, dynamic pressure 17.5MPa, and static pressure 15MPa.

[0044] S4: Spray coating: The protective coating prepared in S3 is sprayed from the spray gun nozzle and applied to the surface of the pretreated pressure vessel substrate. It is then cured for 14 days at 25°C and 60% relative humidity to obtain the protective material.

[0045] Example 2 The composition and preparation process are the same as in Example 1, except that: The ultrasonic treatment parameters in step S11 of the preparation process are set as follows: power 400W, frequency 20kHz, duration 30min, and other steps are the same.

[0046] In step S12 of the preparation process, the pH was adjusted to 8.5, the stirring parameters were set as follows: 300 rpm for 15 min, the temperature stirring parameters were set as follows: 70℃ for 400 rpm for 3 h, and the vacuum drying parameters were set as follows: 60℃ for 60℃, vacuum degree for -0.08 MPa for 12 h. Other steps were the same.

[0047] In the preparation process, the mass ratio of tannic acid to halloysite nanotubes in S12 is 0.2:1, the mass ratio of borax to halloysite nanotubes is 0.05:1, and other components are the same.

[0048] In step S2 of the preparation process, the polyetheramine is preheated to 50°C. The stirring parameters are set as follows: 400 rpm for 15 min, medium speed stirring parameters are set as follows: 500 rpm for 10 min, high speed shear dispersion parameters are set as follows: 1000 rpm for 40 min, and other steps are the same.

[0049] The mixed resin in the S2 preparation process has the following composition of raw materials: based on 100 parts of polyetheramine, 15 parts of diethyltoluenediamine, 3 parts of TA-B@HNTs, and other components are the same.

[0050] In the preparation process, the isocyanate prepolymer in S3 is heated to 58°C, and the mixed resin prepared in S2 is heated to 68°C. The high-pressure impact mixing parameters are set as follows: system pressure 20MPa, dynamic pressure 15MPa, static pressure 12MPa, and other steps are the same.

[0051] Example 3 The composition and preparation process are the same as in Example 1, except that: The ultrasonic treatment parameters in step S11 of the preparation process are set as follows: power 600W, frequency 25kHz, duration 45min, and other steps are the same.

[0052] In step S12 of the preparation process, the pH was adjusted to 10, and the stirring parameters were set as follows: 500 rpm for 25 min, 90℃ for temperature, 600 rpm for 6 h, and 80℃ for temperature, -0.09 MPa for vacuum drying for 24 h. Other steps were the same.

[0053] In the preparation process, the mass ratio of tannic acid to halloysite nanotubes in S12 is 0.5:1, the mass ratio of borax to halloysite nanotubes is 0.15:1, and other components are the same.

[0054] In step S2 of the preparation process, the polyetheramine is preheated to 60°C. The stirring parameters are set as follows: 500 rpm for 30 min, medium speed for 800 rpm for 15 min, and high speed for 1500 rpm for 60 min. Other steps are the same.

[0055] The mixed resin in the S2 preparation process has the following composition of raw materials: based on 100 parts of polyetheramine, 40 parts of diethyltoluenediamine, 10 parts of TA-B@HNTs, and other components are the same.

[0056] In the preparation process, the isocyanate prepolymer in S3 is heated to 62°C, and the mixed resin prepared in S2 is heated to 72°C. The high-pressure impact mixing parameters are set as follows: system pressure 30MPa, dynamic pressure 20MPa, static pressure 18MPa, and other steps are the same.

[0057] Example 4 The composition and preparation process are the same as in Example 1, except that: The ultrasonic treatment parameters in step S11 of the preparation process are set as follows: power 550W, frequency 24kHz, duration 40min, and other steps are the same.

[0058] In step S12 of the preparation process, the pH was adjusted to 9.5, the stirring parameters were set as follows: 330 rpm for 24 min, the temperature stirring parameters were set as follows: 88℃ for 460 rpm for 5.5 h, and the vacuum drying parameters were set as follows: 78℃ for 0.083 MPa for 20 h. Other steps were the same.

[0059] In the preparation process, the mass ratio of tannic acid to halloysite nanotubes in S12 is 0.3:1, the mass ratio of borax to halloysite nanotubes is 0.08:1, and other components are the same.

[0060] In step S2 of the preparation process, the polyetheramine is preheated to 52°C. The stirring parameters are set as follows: 420 rpm for 26 min, medium-speed stirring parameters are set as follows: 750 rpm for 11 min, and high-speed shear dispersion parameters are set as follows: 1100 rpm for 56 min. Other steps are the same.

[0061] The mixed resin in the S2 preparation process has the following composition of raw materials: based on 100 parts of polyetheramine, 38 parts of diethyltoluenediamine, 5 parts of TA-B@HNTs, and other components are the same.

[0062] In the preparation process, the isocyanate prepolymer in S3 is heated to 59°C, and the mixed resin prepared in S2 is heated to 71°C. The high-pressure impact mixing parameters are set as follows: system pressure 28MPa, dynamic pressure 19MPa, static pressure 16MPa, and other steps are the same.

[0063] Comparative Example 1 The composition and preparation process are the same as in Example 1, except that: In step S2 of the preparation process, the TA-B@HNTs functional complex is not added. Instead, unmodified halloysite nanotubes are directly added to the mixed resin at a concentration of 5% of the total amine mass. The other steps are the same.

[0064] Comparative Example 2 The composition and preparation process are the same as in Example 1, except that: In step S3 of the preparation process, high-pressure shock mixing is not used. Instead, components A and B are manually mixed and stirred at room temperature, and then coated into a film. The other steps are the same.

[0065] Samples were taken from the unmodified HNTs in S11 and the TA-B@HNTs functional complex prepared in S12 in Example 1, and tested using a Fourier transform infrared spectrometer (scanning range 4000–500 cm⁻¹). -1 (32 scans), the sample was compressed into tablets using potassium bromide, such as Figure 2 As shown, in the range of 3200–3400 cm -1 The presence of a distinct broad and strong absorption peak is due to the introduction of polyphenolic hydroxyl groups from tannic acid. These phenolic hydroxyl groups in the tannic acid molecule form intermolecular hydrogen bonds with the silanol and aluminol hydroxyl groups on the surface of HNTs, causing the original isolated hydroxyl characteristic peak to shift towards lower wavenumbers, accompanied by a significant peak broadening phenomenon in the 1330–1380 cm⁻¹ range. -1 A new peak appeared, representing the asymmetric stretching vibration of the borate ester bond, at 1080 cm⁻¹. -1 A new peak also appears, which is the symmetric stretching vibration of the borate ester bond.

[0066] Samples of the protective coating prepared in S3 of Example 1 were taken and tested using a Fourier transform infrared spectrometer (scanning range 4000–500 cm⁻¹). -1 (32 scans) Figure 3 As shown, at 2270cm -1 Near the 1640–1670 cm⁻¹ peak, the characteristic peak of the isocyanate group disappeared, indicating that a high reaction conversion rate was achieved through the high-pressure impact mixing process, suggesting that there were no unreacted monomer residues in the system and that the curing reaction was relatively thorough; -1 A strong characteristic peak appeared, indicating the carbonyl stretching vibration of the urea bond, at 1540 cm⁻¹. -1 The presence of strong characteristic peaks representing NH bending vibrations indicates the formation of the polyurea crosslinked backbone.

[0067] Based on Examples 1-4 and Comparative Examples 1-2, samples of the final prepared protective materials were taken for tensile strength testing: the protective materials were cut into dumbbell-shaped specimens and placed in an environment with a temperature of 23°C and a relative humidity of 50% for 4 hours. Then, the thickness at three points along the gauge length of the specimen was measured and the average value was taken. The specimens were then subjected to biaxial tensile testing until fracture (tensile rate 200 mm / min). Ten sets of tests were conducted. Specimens with fracture locations outside the gauge length or with obvious defects were discarded, and the average value was taken.

[0068] Based on Examples 1-4 and Comparative Examples 1-2, samples of the final prepared protective material were taken for limiting oxygen index testing: the protective material was cut into strips (100mm × 10mm × 4mm) and placed in an environment with a temperature of 23℃ and a relative humidity of 50% for 96 hours. A mark was drawn 50mm from the ignition end of the sample, and the oxygen index was measured using an oxygen index meter. The gas source was turned on, and the flow rates of oxygen and nitrogen were adjusted. The entire top surface was ignited using the top ignition method, and the flame duration was not to exceed 30 seconds. The igniter was removed every 5 seconds to observe whether ignition had occurred. Once ignited, the igniter was immediately removed and timing was started. If the sample burning time exceeded 180 seconds or the flame front exceeded the 50mm mark, the oxygen concentration was considered too high. If the flame extinguished before 180 seconds or before 50mm, the oxygen concentration was considered too low. The test was continued step by step to find the reaction pair with an oxygen concentration difference ≤ 1.0%. Six more samples were tested in increments of 0.2%, and the lowest oxygen concentration that could sustain combustion was taken as the limiting oxygen index of the material.

[0069] Based on Examples 1-4 and Comparative Examples 1-2, samples of the final prepared protective materials were taken for salt spray resistance testing: the four sides and back of the sample were sealed with paraffin wax and placed in an environment with a temperature of 23°C and a relative humidity of 50% for 24 hours. Then, the sample was placed in a salt spray test chamber (temperature 35°C, spray collection rate 1.5 mL / h). The sample was at a 20° angle to the vertical direction and sprayed with a sodium chloride solution (mass fraction 5%, pH 7). Five sets of tests were conducted, and the samples were taken out every 50 hours to observe whether blistering or rusting occurred.

[0070] The specific test results are shown in Table 2. Figure 2 , Figure 3 As shown: Table 2 Comparison of core performance of Examples 1-4 and Comparative Examples 1-2 As can be seen from the above comparison results, Example 1 has the best overall performance, and a uniform TA-B hybrid layer is constructed on the surface of HNTs. This structure provides physical reinforcement within the resin and, upon heating, forms a dense, expanded carbon layer to isolate oxygen. Simultaneously, tannic acid captures free radicals on the metal surface and forms a complex passivation layer to prevent corrosion. This demonstrates that Example 1 successfully resolved the trade-off between simultaneously pursuing high strength, high flame retardancy, and high corrosion resistance. Examples 2 to 4 exhibit slightly lower overall performance than Example 1 but still maintain a high level, indicating that excellent performance balance was achieved even with a wide range of parameter variations. Comparative Example 1, due to the use of unmodified HNTs with strong hydrophilicity and poor compatibility with the polyetheramine / isocyanate system, is prone to agglomeration. These agglomerates become stress concentration points, leading to decreased strength and corrosion resistance. Furthermore, it lacks the flame-retardant elements boron / tannic acid, thus failing to simultaneously meet all three performance requirements. Comparative Example 2, with manual mixing, cannot provide the kinetic energy for high-pressure impact mixing, resulting in insufficient material reaction, uneven molecular weight distribution, and easy incorporation of air bubbles. Its mechanical, flame-retardant, and corrosion-resistant properties are the worst, completely failing to solve the problem.

[0071] In summary, it is clear from the above embodiments and comparative examples that the protective coating provided by the present invention has significantly better mechanical, flame retardant, and anti-corrosion properties than traditional solutions. This is attributed to the construction of TA-B@HNTs functional composite filler and the use of high-pressure impact mixing, thereby solving the problem of mutual constraints caused by the pursuit of high strength, high flame retardancy, and high corrosion resistance in protective coatings.

Claims

1. A special explosion-proof and corrosion-resistant pressure vessel protective material, wherein the protective material is a sprayed polyurea reactant, characterized in that: The protective material is made by mixing a mixed resin and an isocyanate prepolymer under high pressure. The mixed resin is composed of a functional composite filler and a resin matrix. The functional composite filler is composed of halloysite nanotubes, tannic acid, and borax. The resin matrix is ​​polyetheramine and diethyltoluenediamine.

2. The special explosion-proof and corrosion-resistant pressure vessel protective material according to claim 1, characterized in that: The mixed resin has the following raw material composition: based on 100 parts of polyetheramine, 15-40 parts of diethyltoluene diamine, and 3-10 parts of functional composite filler.

3. The special explosion-proof and corrosion-resistant pressure vessel protective material according to claim 1, characterized in that: The isocyanate prepolymer has a -NCO mass fraction of 12% to 18%.

4. The special explosion-proof and corrosion-resistant pressure vessel protective material according to claim 1, characterized in that: The functional composite filler contains tannic acid to halloysite nanotubes in a mass ratio of 0.2:1 to 0.5:1, and borax to halloysite nanotubes in a mass ratio of 0.05:1 to 0.15:

1.

5. A method for preparing a special explosion-proof and corrosion-resistant pressure vessel protective material according to any one of claims 1-4, characterized in that, Includes the following steps: S1: Preparation of functional complexes; S11: Add halloysite nanotube powder to deionized water and sonicate to obtain HNTs suspension; S12: Tannic acid and borax are added sequentially to the HNTs suspension prepared in S11, stirred, and the pH is adjusted to 8.5-10. Then, the mixture is heated and stirred, centrifuged, washed, vacuum dried, ground and sieved to obtain the TA-B@HNTs functional complex. S2: Preparation of mixed resin: preheat polyetheramine to 50-60℃, add diethyltoluenediamine, stir, then add TA-B@HNTs functional composite prepared in S12, stir at medium speed first, then disperse by high-speed shearing, degas under vacuum, filter, and store under nitrogen to obtain mixed resin. S3: Preparation of protective materials. The isocyanate prepolymer is heated to 58-62°C, and the mixed resin prepared in S2 is heated to 68-72°C. Then, the two are mixed under high pressure to obtain a protective coating.

6. The method for preparing a special explosion-proof and corrosion-resistant pressure vessel protective material according to claim 5, characterized in that: The halloysite nanotube powder described in S11 has a mass-to-volume ratio of 1:20 g:mL with deionized water. The ultrasonic treatment described in S11 has the following parameter settings: power 400-600W, frequency 20-25kHz, and duration 30-45min.

7. The method for preparing a special explosion-proof and corrosion-resistant pressure vessel protective material according to claim 5, characterized in that: The stirring described in S12 has the following parameters: rotation speed 300-500 rpm, duration 15-25 min; The heating and stirring described in S12 has the following parameters: temperature 70-90℃, rotation speed 400-600rpm, and duration 3-6h. The vacuum drying described in S12 has the following parameters: temperature 60~80℃, vacuum degree -0.08~-0.09MPa, and duration 12~24h.

8. The method for preparing a special explosion-proof and corrosion-resistant pressure vessel protective material according to claim 5, characterized in that: The stirring parameters described in S2 are set as follows: rotation speed 400-500 rpm, duration 15-30 min; The medium-speed stirring described in S2 has the following parameters: rotation speed 500-800 rpm, duration 10-15 min.

9. The method for preparing a special explosion-proof and corrosion-resistant pressure vessel protective material according to claim 5, characterized in that: The high-speed shear dispersion described in S2 has the following parameter settings: rotation speed 1000-1500 rpm, duration 40-60 min; The vacuum degassing described in S2 has the following parameters: temperature 35℃, vacuum degree -0.08MPa, rotation speed 300rpm, and duration 30min.

10. The method for preparing a special explosion-proof and corrosion-resistant pressure vessel protective material according to claim 5, characterized in that: The isocyanate prepolymer described in S3 has a volume flow ratio of 1:1 with the mixed resin. The high-pressure impact mixing described in S3 has the following parameter settings: system pressure 20-30 MPa, dynamic pressure 15-20 MPa, and static pressure 12-18 MPa.

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