Efficient organic-inorganic hybrid bio-based ceramic fireproof coating and preparation method and application thereof

Abstract

The present application relates to a kind of efficient organic-inorganic hybrid bio-based ceramic fireproof coating and its preparation method and application.Preparation method includes: preparation of polyethylene glycol modified phytic acid;Preparation of melamine diborate;Preparation of polyethylene glycol modified phytic acid / melamine diborate-glass powder-gelatin fireproof flame-retardant coating.The present application selects polyethylene glycol PEG to modify phytic acid, the reactivity of the functional modification is reduced, and a suitable product with better subsequent flame-retardant performance is obtained.The low-activity phosphoric acid group in polyethylene glycol modified phytic acid can react with the amino group of melamine diborate to form ionic bond, obtaining intumescent flame retardant, by adding glass powder, realize ceramic fireproof coating, and show more excellent fireproof performance.

Description

Technical Field

[0001] This invention relates to the field of flame retardant materials technology, specifically to a high-efficiency organic-inorganic hybrid bio-based ceramic fire-retardant coating, its preparation method, and its application. Background Technology

[0002] With the continuous development and advancement of flame retardant technology, many new methods for wood flame retardancy have emerged in recent years, mainly categorized into three basic wood treatment methods: surface treatment, veneer treatment, and deep treatment. Surface treatment methods primarily involve directly introducing flame-retardant polymers or monomers onto the wood surface through coating, spraying, or deposition, followed by cross-linking and curing using physicochemical methods to form a heat-insulating protective layer. Common surface treatment methods include surface coating, deposition, and etching. To address the problems inherent in traditional wood flame retardant treatment methods, such as poor compatibility and poor flame retardant durability, and to alleviate the environmental and energy pressures caused by over-reliance on petroleum resources, the introduction of bio-based raw materials into wood flame retardant systems to prepare bio-based flame-retardant coatings has profound practical application value.

[0003] Phytic acid (PA), a high-phosphorus bio-based flame retardant, has attracted much attention in recent years. It has a para-inositol hexaphosphate structure with a six-carbon ring molecular configuration. Phytic acid is readily soluble in ethanol and water, but poorly soluble in anhydrous ether, chloroform, and benzene. Due to its strong acidity, phytic acid readily reacts with the gas source in intumescent flame retardant systems to form salts. Since the matrix resin is mostly composed of polymers, the compatibility between the two is very poor. The resulting coating is generally opaque after curing, and the mixture is merely a simple mixture, leading to poor water resistance in the coating.

[0004] Glass powder, as a low-temperature sintering aid and ceramicization precursor, has shown significant application potential in functional materials, composite materials, and coating technologies in recent years. Due to its tunable softening temperature, chemical stability, and compatibility with various matrices, glass powder has become a key material for achieving low-temperature ceramicization. Summary of the Invention

[0005] The purpose of this invention is to provide a highly efficient organic-inorganic hybrid bio-based ceramic fire-retardant coating, its preparation method, and its application. First, polyethylene glycol (PEG) of different molecular weights is selected as a carbon source to chemically modify phytic acid, thereby reducing the acidity and reactivity of the phosphate groups in phytic acid. Next, a suitable gas source (melamine) is introduced into the phytic acid-g-PEG system to prepare a ternary integrated intumescent flame retardant. Then, the ternary integrated intumescent flame retardant is mixed with glass powder in a certain proportion to prepare a flame-retardant coating with good stability.

[0006] Specifically, the present invention provides the following technical solution: A method for preparing a high-efficiency organic-inorganic hybrid bio-based ceramic fire-retardant coating, wherein the organic-inorganic hybrid bio-based ceramic fire-retardant coating is a polyethylene glycol-modified phytic acid / melamine diborate-glass powder-gelatin fire-retardant coating. The preparation method is as follows: phytic acid is modified with polyethylene glycol, and the prepared melamine diborate is dissolved in the modified phytic acid solution and dried in an oven to prepare a polyethylene glycol-modified phytic acid / melamine diborate flame retardant. Subsequently, the product, glass powder and gelatin are mixed, and the mixed coating is applied to a pure wood board to prepare a polyethylene glycol-modified phytic acid / melamine diborate-glass powder-gelatin fire-retardant coating.

[0007] Specifically, the following steps are included: Step 1: Mix boric acid (H3BO3) and melamine (C3N6H6) in a molar ratio of 1~2:1 and add to deionized water. Stir at 80°C to obtain a transparent solution. Then cool the hot solution to room temperature (15~25°C) until a white precipitate is obtained. Subsequently, heat the white precipitate to dry it to obtain white powdered melamine borate (MB). Step 2: Add phytic acid (PA) (C6H) 18 O 24 P6) was reacted with polyethylene glycol (PEG) at a molar ratio of 1:1~6, nitrogen gas was introduced, and the reaction was carried out in an oil bath to obtain modified phytic acid, namely phytic acid-g-PEG. Step 3: React melamine diborate (MB) and phytic acid-g-PEG at a molar ratio of 1~6:1, add deionized water and stir to mix evenly, the reaction temperature is 60~80℃, after the reaction is complete to form a solution, put it in an oven to dry, and the solid product obtained is phytic acid-g-PEG melamine borate intumescent flame retardant, i.e. PgPMB; Step 4: Mix PgPMB, glass powder and gelatin at a mass ratio of 0.1~0.5:0.01~0.05:1, add deionized water, stir thoroughly at 60~80℃, and then apply to obtain a high-efficiency organic-inorganic hybrid bio-based ceramic fireproof coating.

[0008] Furthermore, the melting temperature of the glass powder is 330~350℃.

[0009] Furthermore, in step one, the amount of deionized water added is 300~500mL, and the stirring time is 0.5~2h.

[0010] Furthermore, in step two, the molecular formula of polyethylene glycol (PEG) is HO(CH2CH2O)nH, and Mn is 200~2000, further selected from any one of molecular weights of 200, 600, 1000, and 2000; the reaction temperature is 135~150℃, and the reaction time is 5~6h.

[0011] Furthermore, in step three, the amount of deionized water added is 150-200 mL, and the stirring time is 1-2 h.

[0012] Furthermore, in step three, the oven temperature is 60~90℃, and the drying time is 18~24h.

[0013] Furthermore, in step four, the amount of deionized water added is 50-100 mL, and the stirring time is 0.5-2 h.

[0014] Furthermore, the coating method in step four includes brush coating, applied to a pure wood panel, with the dried coating weighing 100~300g / m². 2 .

[0015] The high-efficiency organic-inorganic hybrid bio-based ceramic fireproof coating prepared by this invention can be used in flame retardancy, fire prevention, heat insulation and other fields.

[0016] Furthermore, the polyethylene glycol-modified phytic acid / melamine diborate-glass powder-gelatin fire-retardant coating provided by this invention, when applied to the surface of a pure wood board, effectively isolates oxygen and heat from entering the wood during combustion, maintaining the integrity of the wood board. It has significant fire-retardant, fire-resistant, and heat-insulating effects, and also possesses good mechanical properties.

[0017] Compared with the prior art, the beneficial effects of the present invention are: (1) The method of the present invention uses polyethylene glycol (PEG) to modify phytic acid. This functional modification can reduce the reactivity of phytic acid and obtain a suitable product with better subsequent flame retardant properties. The low-activity phosphate groups in PEG-modified phytic acid can react with the amino groups of melamine diborate to form ionic bonds, thereby obtaining an intumescent flame retardant. By adding glass powder, a ceramic fireproof coating is achieved, exhibiting even better fireproof performance.

[0018] (2) The polyethylene glycol-modified phytic acid / melamine diborate-glass powder-gelatin fire-retardant coating prepared by this invention has good flame retardant effect, forms a ceramicized surface, and has good density, thermal stability and heat insulation ability. The coating has strong adhesion and is not easy to fall off. Attached Figure Description

[0019] Figure 1 The reaction equation is for an intumescent flame retardant.

[0020] Figure 2 Thermogravimetric analysis (TGA) curves of the five coating materials in Examples 1–4 and Comparative Example 1 are shown.

[0021] Figure 3 SEM images of five coating materials from Examples 1–4 and Comparative Example 1.

[0022] Figure 4 The heat release rate (HRR) curves and total heat release (THR) curves of the five coating materials in Examples 1–4 and Comparative Example 1 are shown. Detailed Implementation

[0023] 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.

[0024] Example 1 A method for preparing a highly efficient organic-inorganic hybrid bio-based ceramic fire-retardant coating, specifically comprising: (1) Weigh 6.2g of boric acid (H3BO3), add 400mL of deionized water and stir to dissolve. Then add 6.3g of melamine (C3N6H6) (the molar ratio of boric acid to melamine is 2:1) and stir at 80℃ for 1h to obtain a transparent solution. Cool to room temperature (15~25℃) to obtain a white precipitate. Vacuum filter, wash, and then place in an oven at 80℃ for 12h to dry to obtain white powdered melamine diborate (MB).

[0025] (2) Weigh 9.43g of phytic acid (C6H) 18 O 24 P6) solution was added to a three-necked flask, and nitrogen gas was introduced into an oil bath at 135°C. After stirring for 1-2 hours, polyethylene glycol (HO(CH2CH2O)) was added. n 6g of phytic acid and polyethylene glycol (molar ratio of phytic acid to polyethylene glycol 1:3) were reacted at 135℃ for 5h to obtain modified phytic acid-g-PEG.

[0026] (3) such as Figure 1 As shown, 5.43g of melamine borate (MB) was weighed and added to a phytic acid-g-PEG solution (molar ratio of MB to phytic acid-g-PEG 3:1). 200ml of deionized water was added and mixed evenly. The mixture was stirred at 80℃ for 1h. After the reaction was complete, the resulting solution was dried in an oven at 120℃ to obtain the solid product, which is the phytic acid-g-PEG melamine diborate intumescent flame retardant (PgPMB).

[0027] (4) Weigh 8g of gelatin and 2g of PgPMB and add them to 50mL of deionized water. Stir in an oil bath at 80℃ for 0.5h. After stirring thoroughly, apply the mixture to a pure wood board (W1) according to the standard of 200g per square meter after drying.

[0028] Example 2 A method for preparing a highly efficient organic-inorganic hybrid bio-based ceramic fire-retardant coating, specifically comprising: (1) Weigh 6.2g of boric acid, add 400mL of deionized water and stir to dissolve. Then add 6.3g of melamine (the molar ratio of boric acid to melamine is 2:1) and stir at 80℃ for 1h to obtain a transparent solution. Cool to room temperature (15~25℃) to obtain a white precipitate. Vacuum filter, wash, and then place in an oven at 80℃ for 12h to dry to obtain white powdered melamine diborate (MB).

[0029] (2) Weigh 9.43g of phytic acid (C6H) 18 O 24 P6) solution was added to a three-necked flask, and nitrogen gas was introduced into an oil bath at 135°C. After stirring for 1-2 hours, polyethylene glycol (HO(CH2CH2O)) was added. n 6g of phytic acid (H, Mn 200) (molar ratio of phytic acid to polyethylene glycol 1:3) was reacted at 135℃ for 5h to obtain modified phytic acid (phytic acid-g-PEG).

[0030] (3) such as Figure 1 As shown, 5.43g of melamine borate (MB) was weighed and added to a phytic acid-g-PEG solution (molar ratio of MB to phytic acid-g-PEG 3:1). 200ml of deionized water was added and mixed evenly. The mixture was stirred at 80℃ for 1h. After the reaction was complete, the resulting solution was dried in an oven at 120℃ to obtain the solid product, which is the phytic acid-g-PEG melamine diborate intumescent flame retardant (PgPMB).

[0031] (4) Weigh 8g of gelatin, 1.90g of PgPMB and 0.10g of glass powder and add them to 50mL of deionized water. Stir at 80℃ for 0.5h. After stirring thoroughly, apply the mixture to the wooden board (W2) according to the standard of 200g per square meter after drying.

[0032] Example 3 A method for preparing a highly efficient organic-inorganic hybrid bio-based ceramic fire-retardant coating, specifically comprising: (1) Weigh 6.2g of boric acid, add 400mL of deionized water and stir to dissolve. Then add 6.3g of melamine (the molar ratio of boric acid to melamine is 2:1) and stir at 80℃ for 1h to obtain a transparent solution. Cool to room temperature (15~25℃) to obtain a white precipitate. Vacuum filter, wash, and then place in an oven at 80℃ for 12h to dry to obtain white powdered melamine diborate (MB).

[0033] (2) Weigh 9.43g of phytic acid solution and add it to a three-necked flask. In an oil bath at 135℃, purge with nitrogen and stir for 1-2 hours. Then add polyethylene glycol (HO(CH2CH2O)). n 6g of phytic acid (H, Mn 200) (molar ratio of phytic acid to polyethylene glycol 1:3) was reacted at 135℃ for 5h to obtain modified phytic acid (phytic acid-g-PEG).

[0034] (3) such as Figure 1 As shown, 5.43g of melamine borate was weighed and added to a phytic acid-g-PEG solution (molar ratio of MB to phytic acid-g-PEG 3:1), 200ml of deionized water was added and mixed evenly. The mixture was stirred at 80℃ for 1h until the reaction was complete and a solution was formed. The solution was then dried in an oven at 120℃ to obtain a solid product, which is the phytic acid-g-PEG melamine diborate intumescent flame retardant (PgPMB).

[0035] (4) Weigh 8g of gelatin, 1.80g of PgPMB and 0.20g of glass powder and add them to 50mL of deionized water. Stir at 80℃ for 1h. After stirring thoroughly, apply the mixture to the wooden board (W3) according to the standard of 200g per square meter after drying.

[0036] Example 4 A method for preparing a highly efficient organic-inorganic hybrid bio-based ceramic fire-retardant coating, specifically comprising: (1) Weigh 6.2g of boric acid, add 400mL of deionized water and stir to dissolve. Then add 6.3g of melamine (the molar ratio of boric acid to melamine is 2:1) and stir at 80℃ for 1h to obtain a transparent solution. Cool to room temperature (15~25℃) to obtain a white precipitate. Vacuum filter, wash, and then place in an oven at 80℃ for 12h to dry to obtain white powdered melamine diborate (MB).

[0037] (2) Weigh 9.43g of phytic acid solution and add it to a three-necked flask. In an oil bath at 135℃, purge with nitrogen and stir for 1-2 hours. Then add polyethylene glycol (HO(CH2CH2O)). n 6g of phytic acid (H, Mn 200) (molar ratio of phytic acid to polyethylene glycol 1:3) was reacted at 135℃ for 5h to obtain modified phytic acid (phytic acid-g-PEG).

[0038] (3) such as Figure 1As shown, 5.43g of melamine borate was weighed and added to a phytic acid-g-PEG solution (molar ratio of MB to phytic acid-g-PEG 3:1), 200ml of deionized water was added and mixed evenly. The mixture was stirred at 80℃ for 1h until the reaction was complete and a solution was formed. The solution was then dried in an oven at 120℃ to obtain a solid product, which is the phytic acid-g-PEG melamine diborate intumescent flame retardant (PgPMB).

[0039] (4) Weigh 8g of gelatin, 1.70g of PgPMB and 0.30g of glass powder and add them to 50mL of deionized water. Stir at 80℃ for 1h. After stirring thoroughly, apply the mixture to the wooden board (W4) according to the standard of 200g per square meter after drying.

[0040] To highlight the beneficial effects of the present invention, the following comparative examples are provided.

[0041] Comparative Example 1 Weigh out a certain amount of gelatin, add a certain amount of deionized water, stir at 80℃, and apply to the wooden board after thorough stirring.

[0042] Weigh 10g of gelatin and add 50mL of deionized water. Stir at 80℃ and apply to the wood board (W5) after thorough stirring, according to the standard of 200g per square meter after drying.

[0043] The following are performance test experiments of Examples 1-4 and Comparative Example 1.

[0044] (1) Taking the coated wood panels prepared in Examples 1-4 as examples, their flame retardant properties were determined. Limiting oxygen index (LOI) test: LOI was tested on an HC-2 oxygen index meter according to GB / T 2406.2-2009 standard. The sample size was 100×6.5×3 mm. 3 The sample was tested on a CZF-3 type horizontal and vertical combustion tester according to the GB / T 2408-2021 standard, with a sample size of 100×13×3 mm. 3 The specific measurement results are shown in Table 1.

[0045] Table 1 The data in the table above shows that Comparative Example 1 had the lowest LOI of 24%; Example 1 achieved an LOI of 31%, meeting the basic requirements for flame-retardant coatings; the LOI of Example 2 decreased slightly to 30.5%, possibly due to the filler diluting the concentration of the active flame-retardant component; the LOI of Example 3 actually increased to 32.0%, the highest value among all samples, indicating that the synergistic effect between the glass powder and the flame retardant was optimal at this point; the LOI of Example 4 decreased to 29.5%, indicating that excessive filler began to weaken the activity of the flame retardant or disrupt the continuity of the coating. Comparative Example 1 lacks practical flame retardancy; Examples 1–3 all achieved a V0 rating, and Example 4 achieved a V1 rating.

[0046] (2) Thermogravimetric analysis (TGA): The thermal stability of the material was tested using a TGA-Q5000 thermal analyzer. The results are as follows: Figure 2 As shown.

[0047] Depend on Figure 2 It can be seen that, under a nitrogen atmosphere (heating rate of 20 °C / min), the thermogravimetric curves (TGA) of the five coating materials in Examples 1–4 and Comparative Example 1 are shown.

[0048] At 200–300℃, all samples showed a significant weight loss peak of 10–15 wt%. This stage involves the desorption of residual free water and may also be accompanied by the breaking of hydroxyl-hydroxyl groups and a small amount of hydrogen bonds. This phenomenon is common in hydrophilic polymer systems such as gelatin. Compared with Comparative Example 1, the weight loss in this stage of the samples in Examples 1-4 was slightly slower, suggesting that the flame retardant or filler began to exert a certain thermal insulation or chemical crosslinking effect.

[0049] At 300–500℃, Comparative Example 1: the weight loss was the most severe, and the mass decreased rapidly, mainly due to the dehydration of hydroxyl groups to form a carbon skeleton (–OH, C=C / C–O–C) and the breaking of peptide bonds / C–N main chains; Example 1: the decomposition initiation temperature was about 20–30℃ higher than that of Comparative Example 1, and the weight loss rate was significantly slowed down, indicating that the flame retardant promoted the formation of the initial carbon layer and provided some thermal insulation protection. Example 2: The initial decomposition temperature was further delayed, and the weight loss was reduced by about 10% (relatively) compared to Example 1, indicating that a small amount of glass powder began to form a molten "shielding film" at high temperature, sealing some micropores; Example 3: The weight loss was the slightest in this stage, and the carbonization started later and at a lower rate, proving that the synergy between glass powder and flame retardant was most effective at this time - after the glass powder melted, it intertwined with the carbon layer to form a continuous "ceramic-carbon" skeleton, preventing heat / mass transfer; Example 4: The initial decomposition temperature was similar to that of Example 3, but a slight acceleration in weight loss occurred in the 350–450 ℃ range, possibly because excessive glass powder is prone to particle agglomeration, leading to local stress concentration and microcracks in the carbon layer, thus slightly weakening the heat insulation effect.

[0050] At 700 °C, the residual carbon rate of Comparative Example 1 was the lowest at 31%, while Example 1 increased by 6 percentage points to 37%, indicating that the flame retardant itself has a certain carbonization catalytic ability. In Examples 2 and 3, the residual carbon rates reached 39% and 46% respectively in the range of 5–10 wt% glass powder, with particularly significant increases. Although Example 4 was still higher than Example 1 and Example 2, reaching 42%, it was slightly lower than Example 3.

[0051] (3) Scanning electron microscope (SEM): A ZEISS GeminiSEM500 was used for observation. The results are as follows: Figure 3 As shown.

[0052] Depend on Figure 3 It can be seen that the overall carbon layer surface in Example 1 is rough, exhibiting a network-like "sponge" structure with numerous small, interconnected pores. In Example 2, the carbon layer surface shows locally smooth, sheet-like areas; after the glass powder melts, it forms a "film" at the edges of the pores, with fewer pores than in Example 1. In Example 3, the carbon surface has almost no obvious macropores, exhibiting a layered or corrugated dense and continuous structure, with the glass network tightly bonded to the carbon matrix. In Example 4, numerous micron-sized circular particles (aggregated glass powder) and a small number of cracks / micropores are visible on the surface, indicating a less continuous carbon layer. Comparative Example 1 exhibits a typical honeycomb-like macroporous structure with numerous bubble-like pores, thin walls, and large pore sizes.

[0053] (4) Cone calorimeter test: The cone calorimeter test (Suzhou Yangyi Wolchi Testing Technology Co., Ltd.) was conducted according to the ISO 5600 standard test method. The sample size was 100×100×3 mm. 3 The radiative heat flux used in the experiment was 35 kW / m². 2 The result is as follows Figure 4 As shown.

[0054] Combining the heat release rate (HRR) curves of the five samples in the left figure, Comparative Example 1 shows that the highest peak heat release rate (PHRR) is 247 kW / m². 2 It reaches its peak heat release rate and then rapidly declines. During the entire combustion phase, it exhibits the highest heat release per unit area and the worst flame retardant performance. The PHRR of Example 1 is 138 kW / m². 2 Compared to Comparative Example 1, this represents a decrease of approximately 44% and a significant delay in combustion time. Example 2 has a PHRR of 110 kW / m³. 2 Compared to Comparative Example 1, the PHRR decreased by approximately 56%, indicating that a small amount of glass powder was sufficient to dilute the combustible components and provide initial support for the char layer. Example 3 had a PHRR of 88 kW / m³. 2The PHRR was approximately 64% lower than that of Comparative Example 1, the lowest among all systems, indicating that the dense carbon / ceramic skeleton synergistically formed by glass powder and flame retardant was most complete at this point. Example 4 had a PHRR of 149 kW / m³. 2 The peak value was actually higher than that of Example 1, and significantly higher than that of Example 3. This indicates that when the glass powder content is too high, powder agglomeration and insufficient interfacial bonding are likely to occur, leading to early cracking of the carbon layer and reducing the barrier effect. As the glass powder content increases from 0 to 10 wt%, the PHRR first decreases significantly; when the content exceeds 10 wt%, the PHRR begins to rise. This "decline first, then rise" trend reflects the dual role of glass powder: the dilution and inert filler effect can reduce the heat release per unit mass of combustible components; the "ceramic skeleton"-carbon layer composite structure formed by melting can enhance the mechanical strength and closed-pore properties of the carbonized layer; however, when there is too much filler, powder agglomeration and stress concentration at the matrix-filler interface can cause carbon layer cracks and reduce the overall thermal barrier performance. In the right figure, the total heat release (THR) curves of the five samples show that the final THR of Comparative Example 1 is 28 MJ / m. 2 The THR was the highest among the five samples. Example 1 had a THR of 18 MJ / m³. 2 The THR of Example 2 was 14 MJ / m³. 2 The THR of Example 3 was approximately 50% lower than that of Comparative Example 1; the THR of Example 3 was 15 MJ / m³. 2 The THR of Example 4 was 23 MJ / m³. 2 As the glass powder content increased from 0 to 10 wt%, the THR decreased continuously, indicating that the flame-retardant coating could generate a denser, closed-cell char layer barrier during combustion, significantly slowing down the transfer of heat to the substrate. When the glass powder content further increased to 15 wt%, the THR rebounded, reflecting the negative impact of excessive filler on the integrity of the char layer.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing an organic-inorganic hybrid bio-based ceramic fire-retardant coating, characterized in that: The organic-inorganic hybrid bio-based ceramic fire-retardant coating is a polyethylene glycol-modified phytic acid / melamine diborate-glass powder-gelatin fire-retardant coating, and its preparation method includes the following steps: Step 1: Mix boric acid and melamine in a molar ratio of 2:1 and add to deionized water. Stir at 80°C to obtain a transparent solution. Then cool the hot solution to room temperature until a white precipitate is obtained. Subsequently, heat the white precipitate to dry it to obtain white powdered melamine borate. Step 2: Phytic acid (PA) and polyethylene glycol (PEG) are reacted at a molar ratio of 1:3, under nitrogen atmosphere, and in an oil bath to obtain modified phytic acid, i.e., phytic acid-g-PEG; wherein, the molecular formula of polyethylene glycol (PEG) is HO(CH2CH2O). n H and Mn are 200~2000; reaction temperature is 135~150℃; reaction time is 5~6h. Step 3: Melamine diborate and phytic acid-g-PEG are reacted at a molar ratio of 3:

1. Deionized water is added and stirred until homogeneous. The reaction temperature is 60~80℃. After the reaction is complete, a solution is formed. The solution is dried in an oven to obtain a solid product, which is phytic acid-g-PEG melamine borate intumescent flame retardant, i.e., PgPMB. Step 4: Mix PgPMB, glass powder and gelatin in a mass ratio of 1.80:0.20:8, add deionized water, and stir thoroughly at 60~80℃. Then apply the mixture to obtain an organic-inorganic hybrid bio-based ceramic fireproof coating. The melting temperature of the glass powder is 330~350℃.

2. The method for preparing the organic-inorganic hybrid bio-based ceramic fire-retardant coating according to claim 1, characterized in that: In step one, the amount of deionized water added is 300-500 mL, and the stirring time is 0.5-2 h.

3. The method for preparing the organic-inorganic hybrid bio-based ceramic fire-retardant coating according to claim 1, characterized in that: In step three, the amount of deionized water added is 150-200 mL, and the stirring time is 1-2 h.

4. The method for preparing the organic-inorganic hybrid bio-based ceramic fire-retardant coating according to claim 1, characterized in that: In step three, the oven temperature is 60~90℃ and the drying time is 18~24h.

5. The method for preparing the organic-inorganic hybrid bio-based ceramic fire-retardant coating according to claim 1, characterized in that: In step four, the amount of deionized water added is 50-100 mL, and the stirring time is 0.5-2 h.

6. The method for preparing the organic-inorganic hybrid bio-based ceramic fire-retardant coating according to claim 1, characterized in that: The coating method in step four includes brush coating, applied to a pure wood panel, with a dried coating mass of 100~300 g / m². 2 .

7. The organic-inorganic hybrid bio-based ceramic fire-retardant coating obtained by the preparation method according to any one of claims 1-6.

8. The application of the organic-inorganic hybrid bio-based ceramic fireproof coating of claim 7 in flame retardancy and heat insulation.

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