Exterior hydrophobic type flame-retardant fireproof coating

Abstract

This invention relates to the field of coating technology, and more specifically, to an exposed hydrophobic flame-retardant fireproof coating, comprising the following steps: preparation of caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite, preparation of a water-resistant flame-retardant composite, preparation of modified sodium lignosulfonate, and preparation of the exposed hydrophobic flame-retardant fireproof coating. The water-resistant flame-retardant composite effectively utilizes the flame-retardant properties of the caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite. During high-temperature combustion, the caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite forms a dense composite char layer structure, effectively isolating heat and oxygen, thus improving the flame-retardant properties of the fireproof coating. Simultaneously, it also possesses good hydrophobic protective properties, enhancing the hydrophobic properties of the exposed hydrophobic flame-retardant fireproof coating. The modified sodium lignosulfonate effectively improves the UV resistance of the exposed hydrophobic flame-retardant fireproof coating, extending the coating's UV aging resistance life.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and more specifically, to an exposed hydrophobic flame-retardant fireproof coating. Background Technology

[0002] Fire-retardant coatings, as important passive fire-retardant materials in key sectors such as construction, transportation, and energy, are widely used for fire protection of steel structures, concrete structures, and various combustible substrates. Intumescent fire-retardant coatings, due to their rapid expansion and carbonization upon heating, forming a porous, low-thermal-conductivity carbonaceous insulating layer, effectively delay heat transfer to the substrate, have become one of the most widely used types of fire-retardant coatings. Currently, in widely used intumescent flame-retardant systems (such as the APP / PER / MEL system), the key component ammonium polyphosphate has strong hygroscopicity and water solubility. In humid outdoor environments, APP is prone to hydrolysis and migration, causing loss of flame-retardant components and imbalance in the formulation, directly leading to a sharp decline or even complete loss of the coating's fire-retardant performance. While encapsulating APP with technologies such as microencapsulation can improve its water resistance to some extent, it often leads to increased costs, more complex processes, and new problems that may affect the efficiency of acid source release at high temperatures. On the other hand, the strength, density, and continuity of traditional expanded char layers at high temperatures still have room for improvement. Premature collapse, cracking, or excessive porosity of the char layer will weaken its heat insulation and oxygen barrier effects. Although hydrotalcite-based materials have been introduced as flame retardant synergists due to their "laminate barrier effect" and decomposition endothermic properties, their layered structure has limited reinforcing effect on the char layer during the flame retardant process and insufficient chemical inhibition of the combustion chain reaction. It is difficult to construct a composite char layer barrier that is stable, robust, and has excellent heat insulation performance for a long time at high temperatures. Furthermore, hydrotalcite-based materials themselves have a certain degree of hydrophilicity and poor compatibility with organic base materials, which not only reduces the hydrophobicity of the coating but also leads to uneven dispersion of flame retardant components, affecting the flame retardant effect and further impacting the formation of the char layer structure.

[0003] Exposed fire-retardant coatings, when exposed to sunlight for extended periods, suffer from UV damage. UV radiation causes the resin molecules in the base material to break down and degrade, leading to aging phenomena such as fading, chalking, cracking, and decreased adhesion, ultimately resulting in a loss of protective function. To improve the UV aging resistance of exposed fire-retardant coatings, current technologies often employ strategies such as adding UV absorbers, light stabilizers, or nano-shielding fillers. Among these, nano-cerium oxide, due to its excellent UV shielding performance and antioxidant activity, can delay coating aging through both physical scattering and chemical free radical scavenging, making it a research hotspot in recent years. However, nano-cerium oxide particles have extremely high surface energy, and strong hydrogen bonds and van der Waals forces exist between particles, making them prone to aggregation. This results in uneven dispersion within the coating system, reducing the uniformity of UV shielding efficiency and potentially creating defects within the coating, thus accelerating moisture penetration and the aging process. Sodium lignosulfonate, as a renewable biomass derivative, contains a phenylpropane skeleton in its molecular structure that can absorb some ultraviolet light, and phenolic hydroxyl groups that can capture free radicals generated by photo-oxidation reactions, thus possessing natural anti-ultraviolet and antioxidant potential. At the same time, the polar functional groups on the sodium lignosulfonate molecular chain can improve the dispersibility of nanoparticles through steric hindrance and electrostatic repulsion. Therefore, sodium lignosulfonate can be used to modify nanofillers to synergistically improve the anti-aging performance of fire-retardant coatings. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an exposed hydrophobic flame-retardant fireproof coating.

[0005] An exposed hydrophobic flame-retardant fireproof coating has the following components: 25-35 parts by weight of mixed resin, 18-25 parts by weight of water-resistant and flame-retardant composite, 10-12 parts by weight of modified sodium lignosulfonate, 20-30 parts by weight of solvent oil and 1-3 parts by weight of additives. The raw materials for preparing the water-resistant and flame-retardant composite include: 2-5 parts by weight of capsaicin, 200-300 parts by weight of anhydrous ethanol and 20-28 parts by weight of caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite. Caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite is a calcium aluminum lanthanum hydrotalcite intercalated with caffeic acid. Modified sodium lignosulfonate is sodium lignosulfonate with attached nano-cerium oxide particles.

[0006] Preferably, the additives include dispersants, defoamers, and leveling agents.

[0007] Preferably, the mixed resin is composed of acrylic modified alkyd resin and acrylic resin mixed in a weight ratio of 1:(0.7~1.2), and the solvent oil is 200# solvent oil.

[0008] Preferably, the preparation steps include the following: S1: Preparation of caffeic acid intercalated calcium aluminum lanthanum hydrotalcite: A mixed salt solution A was prepared by using calcium nitrate hexahydrate, aluminum nitrate nonahydrate and lanthanum nitrate hexahydrate. A caffeic acid ethanol solution and sodium hydroxide solution were mixed to prepare solution B. Solution B and mixed salt solution A were simultaneously added dropwise to deionized water to remove carbon dioxide. Caffeic acid intercalated calcium aluminum lanthanum hydrotalcite was prepared through a coprecipitation reaction. S2: Preparation of water-resistant flame-retardant composite: Capsaicin was dissolved in anhydrous ethanol to obtain capsaicin ethanol solution. Caffeic acid intercalated calcium aluminum lanthanum hydrotalcite was added to the capsaicin ethanol solution. The mixture was stirred continuously under light protection, nitrogen protection and heating water bath. Subsequently, the mixture was filtered, washed, dried and ground to obtain water-resistant flame-retardant composite. S3: Preparation of modified sodium lignosulfonate: Sodium lignosulfonate and cerium nitrate hexahydrate were added to ethanol solution and deionized water, respectively, to obtain sodium lignosulfonate suspension and cerium nitrate aqueous solution. Under the conditions of heating water bath and continuous stirring, cerium nitrate aqueous solution was added dropwise to sodium lignosulfonate suspension. After the addition was completed, the pH of the resulting mixed solution was controlled to be alkaline. After heating, stirring and standing for a period of time, the solution was filtered, washed, dried and ground to obtain modified sodium lignosulfonate. S4: Preparation of exposed hydrophobic flame-retardant fireproof coating: Mixed resin is added to solvent oil to form a mixed resin solution, then dispersant and defoamer are added and stirred evenly. Water-resistant flame-retardant composite and modified sodium lignosulfonate are added and stirred evenly. Subsequently, leveling agent is added and stirred evenly to obtain exposed hydrophobic flame-retardant fireproof coating.

[0009] Preferably, step S1, the preparation of caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite, specifically includes the following steps: S1.1: Dissolve calcium nitrate hexahydrate, aluminum nitrate nonahydrate and lanthanum nitrate hexahydrate in deionized water and stir magnetically until completely dissolved to prepare a mixed salt A solution with a concentration of 0.5-1 mol / L; S1.2: Add caffeic acid to anhydrous ethanol to prepare a caffeic acid solution with a concentration of 0.08-0.1 g / mL. Add sodium hydroxide to deionized water to remove carbon dioxide and prepare a sodium hydroxide solution with a concentration of 2-4 mol / L. Mix the caffeic acid solution and sodium hydroxide solution thoroughly at a volume ratio of 1:(1-1.5) to obtain solution B. S1.3: Under a nitrogen atmosphere, 80-100 volume parts of deionized water (with carbon dioxide removed) were placed in a reaction flask. The mixture was continuously stirred at 300-400 rpm in a water bath at 60-80°C. During the stirring process, mixed salt solutions A and B (volume ratio 1:(1-1.2)) were simultaneously added dropwise to the reaction flask at a rate of 1-2 mL / min. After the addition was complete, the pH of the solution in the reaction flask was controlled at 9.0-10.0 with a 0.5 mol / L sodium hydroxide solution. The mixture was stirred at a constant temperature for 4-8 hours. After stirring was completed and the mixture was cooled to room temperature, it was filtered, washed 2-4 times with deionized water (with carbon dioxide removed), and vacuum dried in an oven at 60-80°C for 8-12 hours. The mixture was then ground to obtain caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite.

[0010] Preferably, the molar ratio of calcium nitrate hexahydrate, aluminum nitrate nonahydrate, and lanthanum nitrate hexahydrate is: Ca 2+ Al 3+ :La 3+ = (2~3): 1: (0.1~0.3).

[0011] Preferably, the preparation of the water-resistant and flame-retardant composite in step S2 specifically includes the following steps: S2.1: Add 2-5 parts by weight of capsaicin to 200-300 parts by weight of anhydrous ethanol, and stir magnetically until completely dissolved to obtain a capsaicin ethanol solution; S2.2: Take 20-28 parts by weight of caffeic acid intercalated calcium aluminum lanthanum hydrotalcite and add it to the capsaicin ethanol solution obtained in step S2.1. Under light protection, nitrogen protection and a water bath at 40-46°C, stir continuously at a stirring speed of 200-300 rpm for 3-6 hours. Then, after filtration, washing, drying at 50-60°C and grinding, a water-resistant flame-retardant composite is obtained.

[0012] Preferably, the preparation of modified sodium lignosulfonate in step S3 specifically includes the following steps: S3.1: Add 5-10 parts by weight of sodium lignosulfonate to 300-400 parts by weight of 75% ethanol solution, stir magnetically for 20-30 min, adjust the pH to 9.0-10.0 with 0.1 mol / L NaOH solution, and continue stirring magnetically for 20-40 min to obtain sodium lignosulfonate suspension; S3.2: Dissolve 3-7 parts by weight of cerium nitrate hexahydrate in 80-150 parts by weight of deionized water to obtain an aqueous solution of cerium nitrate; S3.3: Under water bath conditions of 50-60℃, the cerium nitrate aqueous solution obtained in step S3.2 is added dropwise to the sodium lignosulfonate suspension obtained in step S3.1 at a rate of 0.5-1.5 mL / min. During the dropwise addition, the mixture is continuously stirred at a stirring speed of 300-400 rpm. After the dropwise addition is completed, a mixed solution is obtained. S3.4: The pH of the mixed solution was controlled at 9.0-10.0 using a 0.1 mol / L NaOH solution. The solution was heated to 60-66℃ and stirred for 3-5 hours. Then, the temperature was raised to 70-78℃ and allowed to stand for 2-4 hours. After filtration, washing, drying at 60-80℃ and grinding, modified sodium lignin sulfonate was obtained.

[0013] Preferably, the preparation of the exposed hydrophobic flame-retardant fire-retardant coating in step S4 specifically includes the following steps: Add 25-35 parts by weight of the mixed resin to 20-30 parts by weight of the solvent oil to form a mixed resin solution. Then add 0.4-1 parts by weight of dispersant and 0.3-1 parts by weight of defoamer. After stirring evenly, add 18-25 parts by weight of water-resistant flame-retardant composite and 10-12 parts by weight of modified sodium lignosulfonate. Stir at 800-1000 rpm for 10-15 minutes. Then add 0.3-1 parts by weight of leveling agent and stir at 500-800 rpm for 10-15 minutes to obtain an exposed hydrophobic flame-retardant fireproof coating.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: 1. This invention involves mixing solutions of calcium, aluminum, and lanthanum metal salts with solution B (an alkaline solution of caffeic acid) for co-precipitation. During co-precipitation, caffeate anions directly enter the interlayer gaps of the forming calcium-aluminum-lanthanum hydrotalcite layers and replace the original nitrate anions in the interlayers. This causes caffeic acid molecules to rearrange between the calcium-aluminum-lanthanum hydrotalcite layers, forming a stable caffeic acid-intercalated calcium-aluminum-lanthanum hydrotalcite. The caffeic acid-intercalated calcium-aluminum-lanthanum hydrotalcite retains the basic flame-retardant framework of hydrotalcite. Furthermore, the caffeic acid in the caffeic acid-intercalated calcium-aluminum-lanthanum hydrotalcite contains aromatic ring structures and phenolic hydroxyl groups. During high-temperature combustion, the phenolic hydroxyl groups of caffeic acid can act as effective hydrogen donors at high temperatures, capturing active free radicals generated during combustion and terminating the combustion chain reaction. In addition, the aromatic ring structure of caffeic acid can increase the char residue rate and promote the formation of char layers. This, in turn, interacts with the calcium oxide, aluminum oxide, and lanthanum oxide metal oxide complex generated by the high-temperature decomposition of calcium-aluminum-lanthanum hydrotalcite, forming a dense composite char layer structure. This more effectively isolates heat and oxygen, improving the flame-retardant and fire-resistant performance of the fire-retardant coating.

[0015] 2. In this invention, by adding caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite to a capsaicin ethanol solution and conducting a stirring reaction under a constant temperature and inert atmosphere, the active hydrogen atoms on the phenolic hydroxyl and amide groups in the capsaicin molecule can form intermolecular hydrogen bonds with the oxygen atoms of the metal hydroxyl groups on the surface of the caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite. This allows capsaicin to be loaded onto the surface of the caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite. Furthermore, the nitrogen and oxygen atoms of the capsaicin amide group contain lone pairs of electrons, which can weakly coordinate with the metal ions exposed on the surface of the caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite, further enhancing the stability of the loading. The water-resistant and flame-retardant composite is formed by the outward orientation of the long-chain alkyl hydrophobic segments of capsaicin on the surface of caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite, which can form a hydrophobic protective layer on the surface of caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite, reducing the surface energy of caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite. At the same time, the long-chain alkyl hydrophobic segments of capsaicin molecules are compatible with the hydrophobic segments of the mixed resin. During the coating film formation process, the alkyl chains can entangle with the resin molecular chains, further enhancing the hydrophobic stability and improving the hydrophobic performance of exposed hydrophobic flame-retardant fireproof coatings.

[0016] 3. In this invention, cerium nitrate is dissolved in water and added dropwise to an alkaline sodium lignosulfonate suspension. At this time, the phenolic hydroxyl groups on the sodium lignosulfonate molecular chain dissociate under alkaline conditions, generating phenolic anions, which give the sodium lignosulfonate molecular surface a strong negative charge. Since the cerium ions and hydroxycerium ions generated by the hydrolysis of cerium nitrate are both positively charged, these positively charged cerium ions can be rapidly adsorbed onto the negatively charged active sites of sodium lignosulfonate through electrostatic attraction. After oxidation and crystallization dehydration to form nanoparticles, the cerium ions are finally anchored on the surface of sodium lignosulfonate, forming a modified... Sodium lignosulfonate; Modified sodium lignosulfonate can reduce the aggregation of cerium oxide nanoparticles through steric hindrance and electrostatic repulsion, allowing them to be uniformly dispersed in the coating and improving UV shielding efficiency. At the same time, sodium lignosulfonate itself has a phenylpropane structure, which can absorb some UV light, and its phenolic hydroxyl groups can capture free radicals generated by photo-oxidation. Thus, the sodium lignosulfonate in modified sodium lignosulfonate and cerium oxide work synergistically to slow down the photodegradation rate of the coating, effectively improve the UV resistance of exposed hydrophobic flame-retardant fireproof coatings, and extend the UV aging resistance life of the coating. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the preparation process of exposed hydrophobic flame-retardant fireproof coatings in this embodiment of the invention.

[0018] Figure 2 The figures show the combustion test results of the exposed hydrophobic flame-retardant fireproof coatings prepared in Examples 1-3 and Comparative Example 1 of this invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0020] An exposed hydrophobic flame-retardant fireproof coating specifically includes the following steps: Preparation of S1 caffeic acid intercalated calcium aluminum lanthanum hydrotalcite S1.1: According to the molar ratio Ca 2+ Al 3+ :La 3+ =2.5:1:0.2 Weigh calcium nitrate hexahydrate, aluminum nitrate nonahydrate, and lanthanum nitrate hexahydrate. Dissolve the weighed calcium nitrate hexahydrate, aluminum nitrate nonahydrate, and lanthanum nitrate hexahydrate in deionized water to remove carbon dioxide. Stir magnetically until completely dissolved to prepare a mixed salt A solution with a concentration of 0.75 mol / L. S1.2: Add caffeic acid to anhydrous ethanol to prepare a caffeic acid solution with a concentration of 0.09 g / mL. Add sodium hydroxide to deionized water to remove carbon dioxide and prepare a sodium hydroxide solution with a concentration of 3 mol / L. Then, mix the caffeic acid solution and the sodium hydroxide solution thoroughly at a volume ratio of 1:1.25 to obtain solution B. S1.3: Under a nitrogen atmosphere, 90 volume parts of deionized water (with carbon dioxide removed) were placed in a reaction flask. The mixture was continuously stirred at 350 rpm in a 70°C water bath. During the stirring process, mixed salt solutions A and B (volume ratio 1:1.1) were simultaneously added dropwise to the reaction flask at a rate of 1.5 mL / min. After the addition was complete, the pH of the solution in the reaction flask was controlled at 9.5 with a 0.5 mol / L sodium hydroxide solution. The mixture was stirred at a constant temperature for 6 hours. After stirring was completed and the mixture was cooled to room temperature, it was filtered, washed three times with deionized water (with carbon dioxide removed), and vacuum dried in a 70°C oven for 10 hours. The mixture was then ground to obtain caffeic acid intercalated calcium aluminum lanthanum hydrotalcite. S2: Preparation of water-resistant and flame-retardant composite, S2.1: Add 3.5 parts by weight of capsaicin to 250 parts by weight of anhydrous ethanol and stir magnetically until completely dissolved to obtain a capsaicin ethanol solution; S2.2: Take 24 parts by weight of caffeic acid intercalated calcium aluminum lanthanum hydrotalcite and add it to the capsaicin ethanol solution obtained in step S2.1. Under light protection, nitrogen protection and a water bath at 43°C, stir continuously at a stirring speed of 250 rpm for 4.5 h. Then, after filtration, washing, drying at 55°C and grinding, a water-resistant flame-retardant composite is obtained. S3: Preparation of modified sodium lignosulfonate S3.1: Add 7.5 parts by weight of sodium lignosulfonate to 350 parts by weight of 75% ethanol solution, stir magnetically for 25 min, adjust the pH to 9.5 with 0.1 mol / L NaOH solution, and continue stirring magnetically for 30 min to obtain sodium lignosulfonate suspension. S3.2: Dissolve 5 parts by weight of cerium nitrate hexahydrate in 115 parts by weight of deionized water to obtain an aqueous solution of cerium nitrate; S3.3: Under the conditions of a water bath at 55℃, the cerium nitrate aqueous solution obtained in step S3.2 is added dropwise to the sodium lignosulfonate suspension obtained in step S3.1 at a rate of 1 mL / min. During the dropwise addition, the mixture is continuously stirred at a stirring speed of 350 rpm. After the dropwise addition is completed, a mixed solution is obtained. S3.4: The pH of the mixed solution was controlled at 9.5 with a NaOH solution of concentration of 0.1 mol / L, heated to 63℃ and stirred for 4 hours, then heated to 74℃ and allowed to stand for 3 hours. After filtration, washing, drying at 70℃ and grinding, modified sodium lignin sulfonate was obtained. S4: Preparation of exposed hydrophobic flame-retardant fireproof coatings 30 parts by weight of mixed resin were added to 25 parts by weight of 200# solvent oil to form a mixed resin solution. The mixed resin was composed of acrylic modified alkyd resin and acrylic resin mixed in a weight ratio of 1:0.95. Then, 0.7 parts by weight of dispersant BYK-110 and 0.65 parts by weight of defoamer BYK-141 were added and stirred evenly. Then, 21.5 parts by weight of water-resistant flame retardant composite and 11 parts by weight of modified sodium lignosulfonate were added and stirred at 900 rpm for 12.5 min. Subsequently, 0.65 parts by weight of leveling agent BYK-330 were added and stirred at 650 rpm for 12.5 min to obtain an exposed hydrophobic flame retardant fireproof coating. Example 2

[0021] An exposed hydrophobic flame-retardant fireproof coating specifically includes the following steps: Preparation of S1 caffeic acid intercalated calcium aluminum lanthanum hydrotalcite S1.1: According to the molar ratio Ca 2+ Al 3+ :La 3+ Weigh out calcium nitrate hexahydrate, aluminum nitrate nonahydrate, and lanthanum nitrate hexahydrate in a ratio of 3:1:0.3. Dissolve the weighed calcium nitrate hexahydrate, aluminum nitrate nonahydrate, and lanthanum nitrate hexahydrate in deionized water after removing carbon dioxide. Stir magnetically until completely dissolved to prepare a mixed salt A solution with a concentration of 1 mol / L. S1.2: Add caffeic acid to anhydrous ethanol to prepare a caffeic acid solution with a concentration of 0.1 g / mL. Add sodium hydroxide to deionized water to remove carbon dioxide and prepare a sodium hydroxide solution with a concentration of 4 mol / L. Then, mix the caffeic acid solution and the sodium hydroxide solution thoroughly at a volume ratio of 1:1.5 to obtain solution B. S1.3: Under a nitrogen atmosphere, 100 volume parts of deionized water (with carbon dioxide removed) were placed in a reaction flask. The mixture was continuously stirred at 400 rpm in an 80°C water bath. During the stirring process, mixed salt solutions A and B (volume ratio 1:1.2) were simultaneously added dropwise to the reaction flask at a rate of 2 mL / min. After the addition was complete, the pH of the solution in the reaction flask was controlled at 10.0 with a 0.5 mol / L sodium hydroxide solution. The mixture was stirred at a constant temperature for 8 hours. After stirring was completed and the mixture was cooled to room temperature, it was filtered, washed four times with deionized water (with carbon dioxide removed), and vacuum dried in an 80°C oven for 12 hours. The mixture was then ground to obtain caffeic acid intercalated calcium aluminum lanthanum hydrotalcite. S2: Preparation of water-resistant and flame-retardant composite, S2.1: Add 5 parts by weight of capsaicin to 300 parts by weight of anhydrous ethanol and stir magnetically until completely dissolved to obtain a capsaicin ethanol solution; S2.2: Take 28 parts by weight of caffeic acid intercalated calcium aluminum lanthanum hydrotalcite and add it to the capsaicin ethanol solution obtained in step S2.1. Under light protection, nitrogen protection and a water bath at 46°C, stir continuously at 300 rpm for 6 hours. Then, after filtration, washing, drying at 60°C and grinding, a water-resistant flame-retardant composite is obtained. S3: Preparation of modified sodium lignosulfonate S3.1: Add 10 parts by weight of sodium lignosulfonate to 400 parts by weight of 75% ethanol solution, stir magnetically for 30 min, adjust the pH to 10.0 with 0.1 mol / L NaOH solution, and continue stirring magnetically for 40 min to obtain sodium lignosulfonate suspension. S3.2: Dissolve 7 parts by weight of cerium nitrate hexahydrate in 150 parts by weight of deionized water to obtain an aqueous solution of cerium nitrate; S3.3: Under the conditions of a water bath at 60℃, the cerium nitrate aqueous solution obtained in step S3.2 is added dropwise to the sodium lignosulfonate suspension obtained in step S3.1 at a rate of 1.5 mL / min. During the dropwise addition, the mixture is continuously stirred at a stirring speed of 400 rpm. After the dropwise addition is completed, a mixed solution is obtained. S3.4: The pH of the mixed solution was controlled at 10.0 using a 0.1 mol / L NaOH solution, heated to 66°C and stirred for 5 hours, then heated to 78°C and allowed to stand for 4 hours. After filtration, washing, drying at 80°C and grinding, modified sodium lignin sulfonate was obtained. S4: Preparation of exposed hydrophobic flame-retardant fireproof coatings 35 parts by weight of mixed resin were added to 30 parts by weight of 200# solvent oil to form a mixed resin solution. The mixed resin was composed of acrylic modified alkyd resin and acrylic resin mixed in a weight ratio of 1:1.2. Then, 1 part by weight of dispersant BYK-110 and 1 part by weight of defoamer BYK-141 were added and stirred evenly. Then, 25 parts by weight of water-resistant flame retardant composite and 12 parts by weight of modified sodium lignosulfonate were added and stirred at a stirring speed of 1000 rpm for 15 min. Subsequently, 1 part by weight of leveling agent BYK-330 was added and stirred at a stirring speed of 800 rpm for 15 min to obtain an exposed hydrophobic flame retardant fireproof coating. Example 3

[0022] An exposed hydrophobic flame-retardant fireproof coating specifically includes the following steps: Preparation of S1 caffeic acid intercalated calcium aluminum lanthanum hydrotalcite S1.1: According to the molar ratio Ca 2+ Al 3+ :La 3+ Weigh out calcium nitrate hexahydrate, aluminum nitrate nonahydrate, and lanthanum nitrate hexahydrate in a ratio of 2:1:0.1. Dissolve the weighed calcium nitrate hexahydrate, aluminum nitrate nonahydrate, and lanthanum nitrate hexahydrate in deionized water after removing carbon dioxide. Stir magnetically until completely dissolved to prepare a mixed salt A solution with a concentration of 0.5 mol / L. S1.2: Add caffeic acid to anhydrous ethanol to prepare a caffeic acid solution with a concentration of 0.08 g / mL. Add sodium hydroxide to deionized water to remove carbon dioxide and prepare a sodium hydroxide solution with a concentration of 2 mol / L. Then, mix the caffeic acid solution and the sodium hydroxide solution thoroughly at a volume ratio of 1:1 to obtain solution B. S1.3: Under a nitrogen atmosphere, 80 volume parts of deionized water (with carbon dioxide removed) were placed in a reaction flask. The mixture was continuously stirred at 300 rpm in a 60°C water bath. During the stirring process, mixed salt solutions A and B (volume ratio 1:1) were simultaneously added dropwise to the reaction flask at a rate of 1 mL / min. After the addition was complete, the pH of the solution in the reaction flask was controlled at 9.0 with a 0.5 mol / L sodium hydroxide solution. The mixture was stirred at a constant temperature for 4 h. After the stirring was completed and the mixture was cooled to room temperature, it was filtered, washed twice with deionized water (with carbon dioxide removed), and vacuum dried in a 60°C oven for 8 h. The mixture was then ground to obtain caffeic acid intercalated calcium aluminum lanthanum hydrotalcite. S2: Preparation of water-resistant and flame-retardant composite, S2.1: Add 2 parts by weight of capsaicin to 200 parts by weight of anhydrous ethanol and stir magnetically until completely dissolved to obtain a capsaicin ethanol solution; S2.2: Take 20 parts by weight of caffeic acid intercalated calcium aluminum lanthanum hydrotalcite and add it to the capsaicin ethanol solution obtained in step S2.1. Under light protection, nitrogen protection and a water bath at 40°C, stir continuously at 200 rpm for 3 hours. Then, after filtration, washing, drying at 50°C and grinding, a water-resistant flame-retardant composite is obtained. S3: Preparation of modified sodium lignosulfonate S3.1: Add 5 parts by weight of sodium lignosulfonate to 300 parts by weight of 75% ethanol solution, stir magnetically for 20 min, adjust the pH to 9.0 with 0.1 mol / L NaOH solution, and continue stirring magnetically for 20 min to obtain sodium lignosulfonate suspension. S3.2: Dissolve 3 parts by weight of cerium nitrate hexahydrate in 80 parts by weight of deionized water to obtain an aqueous solution of cerium nitrate; S3.3: Under the conditions of a water bath at 50℃, the cerium nitrate aqueous solution obtained in step S3.2 is added dropwise to the sodium lignosulfonate suspension obtained in step S3.1 at a rate of 0.5 mL / min. During the dropwise addition, the mixture is continuously stirred at a stirring speed of 300 rpm. After the dropwise addition is completed, a mixed solution is obtained. S3.4: The pH of the mixed solution was controlled at 9.0 using a 0.1 mol / L NaOH solution, heated to 60°C and stirred for 3 hours, then heated to 70°C and allowed to stand for 2 hours. After filtration, washing, drying at 60°C and grinding, modified sodium lignin sulfonate was obtained. S4: Preparation of exposed hydrophobic flame-retardant fireproof coatings 25 parts by weight of the mixed resin were added to 20 parts by weight of 200# solvent oil to form a mixed resin solution. The mixed resin was composed of acrylic modified alkyd resin and acrylic resin mixed in a weight ratio of 1:0.7. Then, 0.4 parts by weight of dispersant BYK-110 and 0.3 parts by weight of defoamer BYK-141 were added and stirred evenly. Then, 18 parts by weight of water-resistant flame retardant composite and 10 parts by weight of modified sodium lignosulfonate were added and stirred at 800 rpm for 10 min. Subsequently, 0.3 parts by weight of leveling agent BYK-330 were added and stirred at 500 rpm for 10 min to obtain an exposed hydrophobic flame retardant fireproof coating.

[0023] Comparative Example 1 Compared with Example 1, Comparative Example 1 differs in that solution B in step S1.3 is replaced with an equal volume of sodium hydroxide solution with a concentration of 3 mol / L to prepare calcium aluminum lanthanum hydrotalcite, and caffeic acid intercalated calcium aluminum lanthanum hydrotalcite in step S2.2 is replaced with an equal weight of calcium aluminum lanthanum hydrotalcite. The remaining steps remain unchanged to prepare an exposed hydrophobic flame-retardant fireproof coating, which is referred to as Comparative Example 1.

[0024] Exposed hydrophobic flame-retardant fire-retardant coatings from Examples 1-3 and Comparative Example 1 were applied to the upper surface of test substrates. All test substrates were 150mm*70mm*3mm steel plates of the same material, with a coating thickness of 2±0.2mm. After curing and drying, samples were formed. Each group of Examples 1-3 and Comparative Example 1 contained 5 samples. The samples were placed on an iron stand with clamps, with the coated surface facing an alcohol torch. The vertical distance between the coated surface and the torch nozzle was 6cm. The alcohol torch was then ignited, and timing began when the flame temperature reached 1000℃. During the timing process, the flame-retardant time ended when charring and cracking appeared on the unexposed side of the sample, and the timing was stopped. The duration of the flame test was the sample's flame-retardant time. The flame-retardant time of each group of samples was recorded, and the average flame-retardant time of each group was calculated as the final result. The results are as follows: Figure 2 As shown.

[0025] like Figure 2 As can be seen, the exposed hydrophobic flame-retardant fire-retardant coatings prepared in Examples 1-3 all exhibited a flame-retardant time >95 min after combustion testing, demonstrating significantly better flame-retardant performance than the exposed hydrophobic flame-retardant fire-retardant coating in Comparative Example 1. This indicates that, compared to ordinary calcium aluminum lanthanum hydrotalcite, caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite provides stronger flame-retardant and fire-retardant properties during high-temperature combustion, effectively isolating heat and oxygen and extending the coating's flame-retardant time.

[0026] Comparative Example 2 Compared with Example 1, the difference of Comparative Example 2 is that step S2 is removed, and the water-resistant flame-retardant compound in step S4 is replaced with an equal part by weight of caffeic acid intercalated calcium aluminum lanthanum hydrotalcite. The other steps remain unchanged, and an exposed hydrophobic flame-retardant fireproof coating is prepared, which is referred to as Comparative Example 2.

[0027] According to the standard GB / T 30693-2014, the water contact angle of the exposed hydrophobic flame-retardant fireproof coatings of Examples 1-3 and Comparative Example 2 was tested using a contact angle measuring instrument. The water contact angle of water on each group of coatings was measured, and the results are shown in Table 1.

[0028] Table 1: Group Water contact angle (°) Example 1 125.3 Example 2 124.5 Example 3 122.8 Comparative Example 2 106.3 As shown in Table 1, the exposed hydrophobic flame-retardant fireproof coatings prepared in Examples 1-3 all have a water contact angle ≥122.8°, exhibiting good hydrophobicity. The hydrophobic effect is significantly better than that of Comparative Example 2. This indicates that by loading capsaicin onto the surface of caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite, a hydrophobic protective effect can be achieved on the caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite, improving the hydrophobic effect of the caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite, thereby effectively improving the hydrophobic performance of the exposed hydrophobic flame-retardant fireproof coating.

[0029] Comparative Example 3 Compared with Example 1, the difference of Comparative Example 3 is that step S3 is removed, and the modified sodium lignosulfonate in step S4 is replaced with an equal part by weight of sodium lignosulfonate. The remaining steps remain unchanged, and an exposed hydrophobic flame-retardant fireproof coating is prepared, which is referred to as Comparative Example 3.

[0030] Comparative Example 4 Compared with Example 1, the difference of Comparative Example 4 is that step S3 is removed, and the modified sodium lignosulfonate in step S4 is replaced with an equal part by weight of nano-cerium oxide particles. The other steps remain unchanged, and an exposed hydrophobic flame-retardant fireproof coating is prepared, which is referred to as Comparative Example 4.

[0031] Comparative Example 5 Compared with Example 1, Comparative Example 5 differs in that steps S3.1 and S3.3 are removed, the mixed solution in step S3.4 is replaced with the cerium nitrate aqueous solution obtained in step S3.2 to prepare nano-cerium oxide particles, the obtained cerium oxide particles are stirred and mixed with 7.5 parts by weight of sodium lignosulfonate to form a mixture, the modified sodium lignosulfonate in step S4 is replaced with an equal part by weight of the mixture, and the remaining steps remain unchanged to prepare an exposed hydrophobic flame-retardant fireproof coating, which is referred to as Comparative Example 5.

[0032] According to the standard GB / T 1865-2009, the exposed hydrophobic flame-retardant fireproof coatings of Examples 1-3 and Comparative Examples 3-5 were subjected to UV aging tests, and the test results are shown in Table 2.

[0033] Table 2: Group UV aging resistance test results Example 1 The 1000-hour test sample showed no peeling, cracking, or powdering. Example 2 The 1000-hour test sample showed no peeling, cracking, or powdering. Example 3 The 1000-hour test sample showed no peeling, cracking, or powdering. Comparative Example 3 The 1000-hour test sample showed some coating peeling and numerous visible cracks and chalking. Comparative Example 4 The 1000-hour test sample showed no detachment, but some areas exhibited minor micro-cracks and slight powdering. Comparative Example 5 The 1000-hour test sample showed no peeling, a few minor cracks, and slight powdering. As shown in Table 2, after UV aging tests, the exposed hydrophobic flame-retardant fire-retardant coatings prepared in Examples 1-3 did not exhibit peeling, cracking, or chalking, demonstrating good aging resistance and UV resistance. However, the exposed hydrophobic flame-retardant fire-retardant coatings prepared using sodium lignosulfonate, nano-cerium oxide particles, and a mixture of sodium lignosulfonate and cerium oxide particles, respectively, all showed varying degrees of cracking and chalking after testing. Comparative Example 3 even showed some coating peeling, indicating poor UV aging resistance. This demonstrates that adding modified sodium lignosulfonate to exposed hydrophobic flame-retardant fire-retardant coatings can effectively improve their UV aging resistance and extend their UV aging lifespan.

[0034] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An exposed hydrophobic flame-retardant fireproof coating, characterized in that, It has the following components: 25-35 parts by weight of mixed resin, 18-25 parts by weight of water-resistant and flame-retardant composite, 10-12 parts by weight of modified sodium lignosulfonate, 20-30 parts by weight of solvent oil and 1-3 parts by weight of additives. The raw materials for preparing the water-resistant and flame-retardant composite include: 2-5 parts by weight of capsaicin, 200-300 parts by weight of anhydrous ethanol and 20-28 parts by weight of caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite. Caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite is a calcium aluminum lanthanum hydrotalcite intercalated with caffeic acid. Modified sodium lignosulfonate is sodium lignosulfonate with attached nano-cerium oxide particles.

2. The exposed hydrophobic flame-retardant fireproof coating according to claim 1, characterized in that, Additives include dispersants, defoamers, and leveling agents.

3. The exposed hydrophobic flame-retardant fireproof coating according to claim 2, characterized in that, The mixed resin is composed of acrylic modified alkyd resin and acrylic resin mixed in a weight ratio of 1:(0.7~1.2), and the solvent oil is 200# solvent oil.

4. The exposed hydrophobic flame-retardant fireproof coating according to claim 1, characterized in that, The preparation steps include the following: S1: Preparation of caffeic acid intercalated calcium aluminum lanthanum hydrotalcite: A mixed salt solution A was prepared by using calcium nitrate hexahydrate, aluminum nitrate nonahydrate and lanthanum nitrate hexahydrate. A caffeic acid ethanol solution and sodium hydroxide solution were mixed to prepare solution B. Solution B and mixed salt solution A were simultaneously added dropwise to deionized water to remove carbon dioxide. Caffeic acid intercalated calcium aluminum lanthanum hydrotalcite was prepared through a coprecipitation reaction. S2: Preparation of water-resistant flame-retardant composite: Capsaicin was dissolved in anhydrous ethanol to obtain capsaicin ethanol solution. Caffeic acid intercalated calcium aluminum lanthanum hydrotalcite was added to the capsaicin ethanol solution. The mixture was stirred continuously under light protection, nitrogen protection and heating water bath. Subsequently, the mixture was filtered, washed, dried and ground to obtain water-resistant flame-retardant composite. S3: Preparation of modified sodium lignosulfonate: Sodium lignosulfonate and cerium nitrate hexahydrate were added to ethanol solution and deionized water, respectively, to obtain sodium lignosulfonate suspension and cerium nitrate aqueous solution. Under the conditions of heating water bath and continuous stirring, cerium nitrate aqueous solution was added dropwise to sodium lignosulfonate suspension. After the addition was completed, the pH of the resulting mixed solution was controlled to be alkaline. After heating, stirring and standing for a period of time, the solution was filtered, washed, dried and ground to obtain modified sodium lignosulfonate. S4: Preparation of exposed hydrophobic flame-retardant fireproof coating: Mixed resin is added to solvent oil to form a mixed resin solution, then dispersant and defoamer are added and stirred evenly. Water-resistant flame-retardant composite and modified sodium lignosulfonate are added and stirred evenly. Subsequently, leveling agent is added and stirred evenly to obtain exposed hydrophobic flame-retardant fireproof coating.

5. The exposed hydrophobic flame-retardant fireproof coating according to claim 4, characterized in that, Step S1, the preparation of caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite, specifically includes the following steps: S1.1: Dissolve calcium nitrate hexahydrate, aluminum nitrate nonahydrate and lanthanum nitrate hexahydrate in deionized water and stir magnetically until completely dissolved to prepare a mixed salt A solution with a concentration of 0.5-1 mol / L; S1.2: Add caffeic acid to anhydrous ethanol to prepare a caffeic acid solution with a concentration of 0.08-0.1 g / mL. Add sodium hydroxide to deionized water to remove carbon dioxide and prepare a sodium hydroxide solution with a concentration of 2-4 mol / L. Mix the caffeic acid solution and sodium hydroxide solution thoroughly at a volume ratio of 1:(1-1.5) to obtain solution B. S1.3: Under a nitrogen atmosphere, 80-100 volume parts of deionized water (with carbon dioxide removed) were placed in a reaction flask. The mixture was continuously stirred at 300-400 rpm in a water bath at 60-80°C. During the stirring process, mixed salt solutions A and B (volume ratio 1:(1-1.2)) were simultaneously added dropwise to the reaction flask at a rate of 1-2 mL / min. After the addition was complete, the pH of the solution in the reaction flask was controlled at 9.0-10.0 with a 0.5 mol / L sodium hydroxide solution. The mixture was stirred at a constant temperature for 4-8 hours. After stirring was completed and the mixture was cooled to room temperature, it was filtered, washed 2-4 times with deionized water (with carbon dioxide removed), and vacuum dried in an oven at 60-80°C for 8-12 hours. The mixture was then ground to obtain caffeic acid-intercalated calcium aluminum lanthanum hydrotalcite.

6. The exposed hydrophobic flame-retardant fireproof coating according to claim 5, characterized in that, The molar ratio of calcium nitrate hexahydrate, aluminum nitrate nonahydrate, and lanthanum nitrate hexahydrate is: Ca 2+ Al 3+ :La 3+ = (2~3): 1: (0.1~0.3).

7. The exposed hydrophobic flame-retardant fireproof coating according to claim 6, characterized in that, The preparation of the water-resistant and flame-retardant composite in step S2 specifically includes the following steps: S2.1: Add 2-5 parts by weight of capsaicin to 200-300 parts by weight of anhydrous ethanol, and stir magnetically until completely dissolved to obtain a capsaicin ethanol solution; S2.2: Take 20-28 parts by weight of caffeic acid intercalated calcium aluminum lanthanum hydrotalcite and add it to the capsaicin ethanol solution obtained in step S2.

1. Under light protection, nitrogen protection and a water bath at 40-46°C, stir continuously at a stirring speed of 200-300 rpm for 3-6 hours. Then, after filtration, washing, drying at 50-60°C and grinding, a water-resistant flame-retardant composite is obtained.

8. The exposed hydrophobic flame-retardant fireproof coating according to claim 7, characterized in that, The preparation of modified sodium lignosulfonate in step S3 specifically includes the following steps: S3.1: Add 5-10 parts by weight of sodium lignosulfonate to 300-400 parts by weight of 75% ethanol solution, stir magnetically for 20-30 min, adjust the pH to 9.0-10.0 with 0.1 mol / L NaOH solution, and continue stirring magnetically for 20-40 min to obtain sodium lignosulfonate suspension; S3.2: Dissolve 3-7 parts by weight of cerium nitrate hexahydrate in 80-150 parts by weight of deionized water to obtain an aqueous solution of cerium nitrate; S3.3: Under water bath conditions of 50-60℃, the cerium nitrate aqueous solution obtained in step S3.2 is added dropwise to the sodium lignosulfonate suspension obtained in step S3.1 at a rate of 0.5-1.5 mL / min. During the dropwise addition, the mixture is continuously stirred at a stirring speed of 300-400 rpm. After the dropwise addition is completed, a mixed solution is obtained. S3.4: The pH of the mixed solution was controlled at 9.0-10.0 using a 0.1 mol / L NaOH solution. The solution was heated to 60-66℃ and stirred for 3-5 hours. Then, the temperature was raised to 70-78℃ and allowed to stand for 2-4 hours. After filtration, washing, drying at 60-80℃ and grinding, modified sodium lignin sulfonate was obtained.

9. The exposed hydrophobic flame-retardant fireproof coating according to claim 8, characterized in that, Step S4, the preparation of exposed hydrophobic flame-retardant fire-retardant coating, specifically includes the following steps: Add 25-35 parts by weight of the mixed resin to 20-30 parts by weight of the solvent oil to form a mixed resin solution. Then add 0.4-1 parts by weight of dispersant and 0.3-1 parts by weight of defoamer. After stirring evenly, add 18-25 parts by weight of water-resistant flame-retardant composite and 10-12 parts by weight of modified sodium lignosulfonate. Stir at 800-1000 rpm for 10-15 minutes. Then add 0.3-1 parts by weight of leveling agent and stir at 500-800 rpm for 10-15 minutes to obtain an exposed hydrophobic flame-retardant fireproof coating.

10. The exposed hydrophobic flame-retardant fireproof coating according to claim 9, characterized in that, The dispersant is at least one of dispersant BYK-110 and dispersant BYK-W968; the defoamer is at least one of defoamer BYK-141 and defoamer BYK-052; and the leveling agent is at least one of leveling agent BYK-306, leveling agent BYK-330 and leveling agent BYK-323.

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