A high-temperature resistant and flame-retardant wood composite board and its preparation method

Abstract

This invention discloses a high-temperature resistant flame-retardant wood composite board and its preparation method, relating to the field of composite board technology. This invention utilizes the strong coordinating groups of tannic acid and phytic acid to form complexes with titanium and fluoride ions, converting the traditionally highly toxic hydrogen fluoride into a stable fluorine-containing flame-retardant phase. Simultaneously, through the chelate network formed by the complexes of tannic acid and iron ions with phytic acid, metal ions are locked in a non-free state within the mineralized layer, achieving an endogenous anti-mildew effect. Then, using bacterial cellulose nanofibers as a three-dimensional template, the complex is guided to grow in a restricted manner within the wood cell wall, forming a continuously coated fluorine-doped titanium dioxide and titanium polyphosphate hybrid shell. This shell then reacts with an adhesive to construct a chemically bonded interface. Simultaneously, the polyphosphate released by the thermal decomposition of phytic acid synergistically forms a ceramic phase with titanium dioxide, and the trimethyl borate in the adhesive decomposes into boron oxide at high temperatures, further enhancing the flame retardancy of the matrix.

Description

Technical Field

[0001] This invention relates to the field of composite board technology, specifically to a high-temperature resistant and flame-retardant wood composite board and its preparation method. Background Technology

[0002] Wood-based composite materials are widely used in building decoration, furniture manufacturing, and interior decoration due to their advantages such as lightweight, high strength, recyclability, and natural aesthetics. However, the inherent flammability and susceptibility to mold in wood limit its application in many scenarios with high requirements for fire safety and hygienic durability. To improve the flame retardant properties of wood, green flame retardants based on biomass raw materials have received widespread attention in recent years.

[0003] Patent CN110524657A discloses a phytic acid flame-retardant wood and its preparation method. Its main improvement lies in the process of vacuum-treating the wood followed by impregnation with a phytic acid solution under high pressure. This technical solution utilizes the acid produced by the thermal decomposition of phytic acid to catalyze the formation of a protective char layer in the wood, which insulates against heat and reduces the release of flammable gases. However, the patent explicitly points out that treating wood solely with phytic acid "still suffers from high smoke release and poor char formation." Therefore, it further introduces metal salts (such as zinc acetate) to synergistically retard the flame with phytic acid, utilizing the relatively stable metal / phosphorus crystalline compounds generated during combustion to inhibit the flame.

[0004] While the above-mentioned technical solutions have improved the shortcomings of phytic acid when used alone to some extent, they still have the following defects: First, the solution only focuses on improving flame retardancy and smoke suppression performance, without addressing the bonding strength of wood composite materials. The acidification of the wood surface after phytic acid impregnation may hinder the curing of the adhesive, making it difficult to achieve both flame retardancy and bonding strength. Second, the introduced metal salts (such as zinc acetate) enter the wood in ionic form and lack an effective immobilization mechanism. They may be lost with moisture during use, which not only affects the flame retardancy durability but may also provide a metal nutrient source for mold growth, exacerbating the risk of mold growth in the wood. Third, the solution only constructs the char layer from the perspective of condensed phase flame retardancy, lacking an effective means to address the problem of flame penetration caused by the shrinkage and cracking of the adhesive layer at high temperatures. The overall functional dimension of the flame retardant system is relatively simple.

[0005] Therefore, how to effectively avoid the adverse effects on bonding strength while utilizing biomass flame retardant components such as phytic acid, and how to simultaneously achieve multi-functional synergistic improvement such as high-efficiency flame retardancy, long-lasting mildew prevention and mechanical enhancement through reasonable component design, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a high-temperature resistant and flame-retardant wood composite board and its preparation method, so as to solve the problems existing in the prior art.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a high-temperature resistant and flame-retardant wood composite board, wherein the high-temperature resistant and flame-retardant wood composite board uses pretreated poplar veneer as the substrate, and is obtained by vacuum pressure impregnation with mineralized liquid, coating with modified adhesive, and then hot pressing. The mineralizing solution contains ammonium fluorotitanate, tannic acid, phytic acid, bacterial cellulose nanofiber dispersion, ferric chloride hexahydrate, and deionized water. The modified adhesive is a compound of phenolic resin adhesive and trimethyl borate.

[0008] Furthermore, a method for preparing a high-temperature resistant and flame-retardant wood composite board includes the following steps: s1. Take poplar veneer and perform wood veneer pretreatment. Dry it at 60℃ and vacuum degree of -0.085~-0.095MPa for 2h to obtain pretreated poplar veneer. s2. Add lactic acid to deionized water and stir at 200-300 rpm until completely dissolved. Then add tannic acid, phytic acid, ferric chloride hexahydrate, and bacterial cellulose nanofiber dispersion in sequence. Adjust the pH of the solution to 4-5 with dilute ammonia water and sonicate at 300W for 10 min. Finally, add ammonium fluorotitanate and stir at 300-400 rpm for 30-60 min to obtain the mineralized solution. s3. Vacuum the pretreated poplar veneer and hold it, then inject mineralization solution to completely immerse the veneer, pressurize and hold it, then take out the veneer and dry it at 60°C to the target moisture content to obtain mineralized veneer; s4. Mix phenolic resin adhesive with trimethyl borate and stir at 300-500 rpm for 15-30 min to obtain modified adhesive; s5. Apply modified adhesive to the surface of the mineralized veneer, and assemble the veneer in the direction of grain. The number of veneers used is 3. First, pre-press at a pressure of 0.5~1MPa for 10 minutes, and then hot press to form a high-temperature resistant and flame-retardant wood composite board.

[0009] Furthermore, the poplar veneer mentioned in step s1 has a thickness of 3 mm and an initial moisture content of 8%.

[0010] Furthermore, in step s2, the mass ratio of lactic acid, deionized water, tannic acid, phytic acid, ferric chloride hexahydrate, bacterial cellulose nanofiber dispersion, and ammonium fluorotitanate is 0.3:100:(2~6):(1~3):(0.5~1):(0.5~2.5):(5~15).

[0011] Furthermore, the bacterial cellulose nanofiber dispersion in step s2 is a bacterial cellulose nanofiber dispersion with a solid content of 1%.

[0012] Furthermore, in step s3, the vacuum is evacuated to a vacuum level of -0.09 MPa and maintained for 30 minutes; then the pressure is increased to a pressure of 0.6~0.9 MPa and maintained for 2~4 hours.

[0013] Furthermore, step s3 involves drying to a target moisture content of 12%.

[0014] Furthermore, in step s4, the mass ratio of phenolic resin adhesive to trimethyl borate is 100:(3~7).

[0015] Furthermore, the amount of modified adhesive applied in step s5 is 120~160 g / m³. 2 .

[0016] Furthermore, the hot pressing process parameters in step s5 are: temperature 160~175℃, pressure 1.2~1.5MPa, and time 12min.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention utilizes the strong coordination groups of tannic acid and phytic acid to instantly capture titanium and fluoride ions generated by the hydrolysis of ammonium fluorotitanate and form complexes, converting the traditionally highly toxic hydrogen fluoride into a stable fluorine-containing flame-retardant phase. This avoids the acid-induced damage to wood cellulose caused by free fluoride ions. Furthermore, through the chelate network formed by the complex of tannic acid and iron ions with phytic acid, metal ions are locked in a non-free state within the mineralized layer. This not only blocks the metal nutrient source available to mold but also reduces the hygroscopicity of wood through the dense shell, achieving an endogenous anti-mold effect. Subsequently, bacterial cellulose nanofibers are used as a three-dimensional template to guide the restricted growth of this complex within the wood cell wall, forming a continuously coated hybrid shell of fluorine-doped titanium dioxide and titanium polyphosphate. The abundant titanium and fluorine hydroxyl groups on the shell surface... The hydroxyl groups in the adhesive undergo a dehydration condensation reaction, forming a chemical bonding interface between the wood, the mineralized layer, and the adhesive layer, significantly improving the bonding strength. At high temperatures, fluorine-doped titanium dioxide in the mineralized layer acts as Lewis acid sites, catalyzing the pyrolysis of wood from chain breakage and volatilization to dehydration and carbonization. Simultaneously, the polyphosphoric acid released by the pyrolysis of phytic acid synergistically forms a titanium phosphorus oxygen amorphous ceramic phase with titanium dioxide, filling the pores of the carbon layer and inhibiting oxygen diffusion. Then, trimethyl borate in the adhesive decomposes into boron oxide at high temperatures, which reacts with the titanium dioxide released from the mineralized layer and the wood carbon layer to form a borosilicate glass phase. Its micro-expansion properties seal the cracks generated by the pyrolysis of the adhesive layer, thereby preventing flame penetration caused by the shrinkage and cracking of the adhesive layer at high temperatures, thus further improving the flame retardancy of the matrix. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The test methods for various indicators of the high-temperature resistant and flame-retardant wood composite boards produced in the following embodiments are as follows: Adhesion strength: Take examples and comparative examples of the same size and test their adhesion strength according to GB / T17657-2022 with a tensile speed of 5 mm / min.

[0020] Limiting oxygen index: Examples and comparative examples of the same size were tested according to GB / T2406.2.

[0021] Anti-mildew performance: According to GB / T18261, Aspergillus niger, Trichoderma viride, and Penicillium citrinum were selected as test strains for the same size examples and comparative examples. After constant temperature incubation for 28 days, the growth of mold on the test specimens was observed and the anti-mildew level was evaluated.

[0022] Example 1

[0023] s1. Take poplar veneer and perform wood veneer pretreatment by drying at 60℃ and vacuum degree of -0.085MPa for 2 hours to obtain pretreated poplar veneer; the thickness of the poplar veneer is 3mm and the initial moisture content is 8%; s2. Add lactic acid to deionized water and stir at 200 rpm until completely dissolved. Then, add tannic acid, phytic acid, ferric chloride hexahydrate, and bacterial cellulose nanofiber dispersion in sequence. Adjust the pH of the solution to 4 with dilute ammonia water, and sonicate at 300W for 10 min. Finally, add ammonium fluorotitanate and stir at 300 rpm for 30 min to obtain a mineralized solution. The mass ratio of lactic acid, deionized water, tannic acid, phytic acid, ferric chloride hexahydrate, bacterial cellulose nanofiber dispersion, and ammonium fluorotitanate is 0.3:100:2:1:0.5:0.5:5. The bacterial cellulose nanofiber dispersion is a bacterial cellulose nanofiber dispersion with a solid content of 1%. s3. Vacuum the pretreated poplar veneer to a vacuum degree of -0.09MPa and maintain for 30min. Then inject mineralization solution to completely immerse the veneer, pressurize to a pressure of 0.6MPa and maintain for 2h. Then take out the veneer and dry it at 60℃ to a target moisture content of 12% to obtain mineralized veneer. s4. Mix phenolic resin adhesive with trimethyl borate and stir at 300 rpm for 15 min to obtain modified adhesive; the mass ratio of phenolic resin adhesive to trimethyl borate is 100:3. s5. Apply a modified adhesive to the surface of the mineralized veneer, with an adhesive application rate of 120 g / m². 2 The blanks are assembled along the grain direction, using 3 veneers. They are first pre-pressed at a pressure of 0.5MPa for 10 minutes, and then hot-pressed at a temperature of 160℃, a pressure of 1.2MPa, and a time of 12 minutes to obtain a high-temperature resistant and flame-retardant wood composite board.

[0024] Example 2

[0025] s1. Poplar veneer is subjected to veneer pretreatment by drying at 60℃ and a vacuum degree of -0.09MPa for 2 hours to obtain pretreated poplar veneer; the thickness of the poplar veneer is 3mm and the initial moisture content is 8%; s2. Add lactic acid to deionized water and stir at 250 rpm until completely dissolved. Then, add tannic acid, phytic acid, ferric chloride hexahydrate, and bacterial cellulose nanofiber dispersion in sequence. Adjust the pH of the solution to 4.3 with dilute ammonia. Sonicate at 300W for 10 min. Finally, add ammonium fluorotitanate and stir at 350 rpm for 45 min to obtain a mineralized solution. The mass ratio of lactic acid, deionized water, tannic acid, phytic acid, ferric chloride hexahydrate, bacterial cellulose nanofiber dispersion, and ammonium fluorotitanate is 0.3:100:4:2:0.8:1.5:10. The bacterial cellulose nanofiber dispersion is a bacterial cellulose nanofiber dispersion with a solid content of 1%. s3. Vacuum the pretreated poplar veneer to a vacuum degree of -0.09MPa and maintain for 30min. Then inject mineralization solution to completely immerse the veneer, pressurize to a pressure of 0.75MPa and maintain for 3h. Then take out the veneer and dry it at 60℃ to a target moisture content of 12% to obtain mineralized veneer. s4. Mix phenolic resin adhesive with trimethyl borate and stir at 400 rpm for 23 min to obtain modified adhesive; the mass ratio of phenolic resin adhesive to trimethyl borate is 100:4. s5. Apply a modified adhesive to the surface of the mineralized veneer, with an adhesive application rate of 140 g / m². 2 The blanks are assembled along the grain direction, using 3 veneers. They are first pre-pressed at a pressure of 0.7MPa for 10 minutes, and then hot-pressed at a temperature of 167℃, a pressure of 1.4MPa, and a time of 12 minutes to obtain a high-temperature resistant and flame-retardant wood composite board.

[0026] Example 3

[0027] s1. Take poplar veneer and perform wood veneer pretreatment by drying at 60℃ and vacuum degree of -0.095MPa for 2 hours to obtain pretreated poplar veneer; the thickness of the poplar veneer is 3mm and the initial moisture content is 8%; s2. Add lactic acid to deionized water and stir at 300 rpm until completely dissolved. Then, add tannic acid, phytic acid, ferric chloride hexahydrate, and bacterial cellulose nanofiber dispersion in sequence. Adjust the pH of the solution to 5 with dilute ammonia water, and sonicate at 300W for 10 min. Finally, add ammonium fluorotitanate and stir at 400 rpm for 60 min to obtain a mineralized solution. The mass ratio of lactic acid, deionized water, tannic acid, phytic acid, ferric chloride hexahydrate, bacterial cellulose nanofiber dispersion, and ammonium fluorotitanate is 0.3:100:6:3:1:2.5:15. The bacterial cellulose nanofiber dispersion is a bacterial cellulose nanofiber dispersion with a solid content of 1%. s3. Vacuum the pretreated poplar veneer to a vacuum degree of -0.09MPa and maintain for 30min. Then inject mineralization solution to completely immerse the veneer, pressurize to a pressure of 0.9MPa and maintain for 4h. Then take out the veneer and dry it at 60℃ to a target moisture content of 12% to obtain mineralized veneer. s4. Mix phenolic resin adhesive with trimethyl borate and stir at 500 rpm for 30 min to obtain modified adhesive; the mass ratio of phenolic resin adhesive to trimethyl borate is 100:7. s5. Apply a modified adhesive to the surface of the mineralized veneer, with an adhesive application rate of 160 g / m². 2 The blanks are assembled along the grain direction, using 3 veneers. They are first pre-pressed at a pressure of 1MPa for 10 minutes, and then hot-pressed at a temperature of 175℃, a pressure of 1.5MPa, and a time of 12 minutes to obtain a high-temperature resistant and flame-retardant wood composite board.

[0028] Example 4

[0029] s1. Poplar veneer is subjected to veneer pretreatment by drying at 60℃ and a vacuum degree of -0.09MPa for 2 hours to obtain pretreated poplar veneer; the thickness of the poplar veneer is 3mm and the initial moisture content is 8%; s2. Add lactic acid to deionized water and stir at 250 rpm until completely dissolved. Then, add tannic acid, phytic acid, ferric chloride hexahydrate, and bacterial cellulose nanofiber dispersion in sequence. Adjust the pH of the solution to 4.3 with dilute ammonia water, and sonicate at 300W for 10 min. Finally, add ammonium fluorotitanate and stir at 350 rpm for 45 min to obtain a mineralized solution. The mass ratio of lactic acid, deionized water, tannic acid, phytic acid, ferric chloride hexahydrate, bacterial cellulose nanofiber dispersion, and ammonium fluorotitanate is 0.3:100:4:2:0.8:0.1:10. The bacterial cellulose nanofiber dispersion is a bacterial cellulose nanofiber dispersion with a solid content of 1%. s3. Vacuum the pretreated poplar veneer to a vacuum degree of -0.09MPa and maintain for 30min. Then inject mineralization solution to completely immerse the veneer, pressurize to a pressure of 0.75MPa and maintain for 3h. Then take out the veneer and dry it at 60℃ to a target moisture content of 12% to obtain mineralized veneer. s4. Mix phenolic resin adhesive with trimethyl borate and stir at 400 rpm for 23 min to obtain modified adhesive; the mass ratio of phenolic resin adhesive to trimethyl borate is 100:4. s5. Apply a modified adhesive to the surface of the mineralized veneer, with an adhesive application rate of 140 g / m². 2 The blanks are assembled along the grain direction, using 3 veneers. They are first pre-pressed at a pressure of 0.7MPa for 10 minutes, and then hot-pressed at a temperature of 167℃, a pressure of 1.4MPa, and a time of 12 minutes to obtain a high-temperature resistant and flame-retardant wood composite board.

[0030] Example 5

[0031] s1. Poplar veneer is subjected to veneer pretreatment by drying at 60℃ and a vacuum degree of -0.09MPa for 2 hours to obtain pretreated poplar veneer; the thickness of the poplar veneer is 3mm and the initial moisture content is 8%; s2. Lactic acid is added to deionized water and stirred at 250 rpm until completely dissolved. Then, tannic acid, phytic acid, ferric chloride hexahydrate, and bacterial cellulose nanofiber dispersion are added sequentially. The pH of the solution is adjusted to 4.3 with dilute ammonia. The solution is ultrasonically dispersed at 300W for 10 min. Finally, ammonium fluorotitanate is added and stirred at 350 rpm for 45 min to obtain a mineralized solution. The mass ratio of lactic acid, deionized water, tannic acid, phytic acid, ferric chloride hexahydrate, bacterial cellulose nanofiber dispersion, and ammonium fluorotitanate is 0.3:100:0.5:0.2:0.8:1.5:10. The bacterial cellulose nanofiber dispersion is a bacterial cellulose nanofiber dispersion with a solid content of 1%. s3. Vacuum the pretreated poplar veneer to a vacuum degree of -0.09MPa and maintain for 30min. Then inject mineralization solution to completely immerse the veneer, pressurize to a pressure of 0.75MPa and maintain for 3h. Then take out the veneer and dry it at 60℃ to a target moisture content of 12% to obtain mineralized veneer. s4. Mix phenolic resin adhesive with trimethyl borate and stir at 400 rpm for 23 min to obtain modified adhesive; the mass ratio of phenolic resin adhesive to trimethyl borate is 100:4. s5. Apply a modified adhesive to the surface of the mineralized veneer, with an adhesive application rate of 140 g / m². 2 The blanks are assembled along the grain direction, using 3 veneers. They are first pre-pressed at a pressure of 0.7MPa for 10 minutes, and then hot-pressed at a temperature of 167℃, a pressure of 1.4MPa, and a time of 12 minutes to obtain a high-temperature resistant and flame-retardant wood composite board.

[0032] Example 6

[0033] s1. Poplar veneer is subjected to veneer pretreatment by drying at 60℃ and a vacuum degree of -0.09MPa for 2 hours to obtain pretreated poplar veneer; the thickness of the poplar veneer is 3mm and the initial moisture content is 8%; s2. Lactic acid is added to deionized water and stirred at 250 rpm until completely dissolved. Then, tannic acid, phytic acid, ferric chloride hexahydrate, and bacterial cellulose nanofiber dispersion are added sequentially. The pH of the solution is adjusted to 4.3 with dilute ammonia. The solution is ultrasonically dispersed at 300W for 10 min. Finally, ammonium fluorotitanate is added and stirred at 350 rpm for 45 min to obtain a mineralized solution. The mass ratio of lactic acid, deionized water, tannic acid, phytic acid, ferric chloride hexahydrate, bacterial cellulose nanofiber dispersion, and ammonium fluorotitanate is 0.3:100:4:2:0.8:1.5:20. The bacterial cellulose nanofiber dispersion is a bacterial cellulose nanofiber dispersion with a solid content of 1%. s3. Vacuum the pretreated poplar veneer to a vacuum degree of -0.09MPa and maintain for 30min. Then inject mineralization solution to completely immerse the veneer, pressurize to a pressure of 0.75MPa and maintain for 3h. Then take out the veneer and dry it at 60℃ to a target moisture content of 12% to obtain mineralized veneer. s4. Mix phenolic resin adhesive with trimethyl borate and stir at 400 rpm for 23 min to obtain modified adhesive; the mass ratio of phenolic resin adhesive to trimethyl borate is 100:4. s5. Apply a modified adhesive to the surface of the mineralized veneer, with an adhesive application rate of 140 g / m². 2The blanks are assembled along the grain direction, using 3 veneers. They are first pre-pressed at a pressure of 0.7MPa for 10 minutes, and then hot-pressed at a temperature of 167℃, a pressure of 1.4MPa, and a time of 12 minutes to obtain a high-temperature resistant and flame-retardant wood composite board.

[0034] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that ammonium fluorotitanate is not added; the remaining steps are the same as in Example 2.

[0035] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that tannic acid and phytic acid are not added; the remaining steps are the same as in Example 2.

[0036] Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that no bacterial cellulose nanofiber dispersion was added; the remaining steps are the same as in Example 2.

[0037] Comparative Example 4 The difference between Comparative Example 4 and Example 2 is that ferric chloride hexahydrate and trimethyl borate are not added; the remaining steps are the same as in Example 2.

[0038] Comparative Example 5 The difference between Comparative Example 5 and Example 2 is that steps s2 and s3 are omitted, and step s5 is replaced with: applying a modified adhesive to the surface of the pretreated poplar veneer, with an adhesive application amount of 140 g / m². 2 The blanks are assembled along the grain direction, using 3 veneers. They are first pre-pressed at a pressure of 0.7 MPa for 10 minutes, and then hot-pressed at a temperature of 167°C, a pressure of 1.4 MPa, and a time of 12 minutes to obtain a high-temperature resistant and flame-retardant wood composite board. The remaining steps are the same as in Example 2.

[0039] Example of effect Table 1 below shows the performance analysis results of the high-temperature resistant and flame-retardant wood composite boards using Examples 1 to 6 and Comparative Examples 1 to 5 of the present invention.

[0040] Table 1 Performance test results of the examples and comparative examples A comparison of the experimental results of the embodiments and comparative examples in Table 1 reveals that this invention utilizes the strong coordination groups of tannic acid and phytic acid to capture titanium ions and fluoride ions generated by the hydrolysis of ammonium fluorotitanate and form a complex, thereby forming a stable fluorinated flame-retardant phase. Furthermore, through the chelate network formed by the complex of tannic acid and iron ions with phytic acid, metal ions are locked in a non-free state within the mineralized layer, blocking the metal nutrient source available to mold and reducing the hygroscopicity of wood through the dense shell, achieving a mold-resistant matrix effect. Then, bacterial cellulose nanofibers are used as a three-dimensional template to guide the restricted growth of this complex within the wood cell wall, forming a continuously coated fluorine-doped titanium dioxide and titanium polyphosphate hybrid shell. This shell surface... The abundant titanium hydroxyl and fluorine hydroxyl groups undergo dehydration condensation reactions with the hydroxyl groups in the adhesive to form a chemical bonding interface, which significantly improves the bonding strength. At high temperatures, the fluorine-doped titanium dioxide in the mineralized layer acts as Lewis acid sites, catalyzing the pyrolysis of wood from chain breaking and volatilization to dehydration and carbonization. At the same time, the polyphosphoric acid released by the pyrolysis of phytic acid synergistically forms an amorphous ceramic phase with titanium dioxide, filling the pores of the carbon layer and inhibiting oxygen diffusion. Then, trimethyl borate in the adhesive decomposes into boron oxide at high temperatures, which reacts with the titanium dioxide released from the mineralized layer and the wood carbon layer to form a borosilicate glass phase. The micro-expansion properties of the borosilicate glass phase seal the cracks generated by the pyrolysis of the adhesive layer, further improving the flame retardancy of the matrix.

[0041] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A high-temperature resistant and flame-retardant wood composite board, characterized in that, The high-temperature resistant and flame-retardant wood composite board is made by using pretreated poplar veneer as the base material, and is obtained by vacuum pressure impregnation with mineral solution, coating with modified adhesive, and then hot pressing. The mineralizing solution contains ammonium fluorotitanate, tannic acid, phytic acid, bacterial cellulose nanofiber dispersion, ferric chloride hexahydrate, and deionized water. The modified adhesive is a compound of phenolic resin adhesive and trimethyl borate.

2. The method for preparing a high-temperature resistant and flame-retardant wood composite board according to claim 1, characterized in that, Includes the following steps: s1. Take poplar veneer for wood veneer pretreatment, and then vacuum dry it to obtain pretreated poplar veneer; s2. Add lactic acid to deionized water and stir until completely dissolved. Then add tannic acid, phytic acid, ferric chloride hexahydrate, and bacterial cellulose nanofiber dispersion in sequence. Adjust the pH of the solution to 4-5 with dilute ammonia water, disperse by ultrasonication, and finally add ammonium fluorotitanate. After stirring, a mineralized solution is obtained. s3. Vacuum the pretreated poplar veneer and hold it, then inject mineralization solution to completely immerse the veneer, pressurize and hold it, then take out the veneer and dry it to the target moisture content to obtain mineralized veneer; s4. Phenolic resin adhesive is mixed with trimethyl borate to obtain a modified adhesive; s5. Apply modified adhesive to the surface of the mineralized veneer, and then assemble and hot-press it in the direction of the grain to obtain a high-temperature resistant and flame-retardant wood composite board.

3. The method for preparing a high-temperature resistant and flame-retardant wood composite board according to claim 2, characterized in that, The poplar veneer mentioned in step s1 has a thickness of 3 mm and an initial moisture content of 8%.

4. The method for preparing a high-temperature resistant and flame-retardant wood composite board according to claim 2, characterized in that, The mass ratio of lactic acid, deionized water, tannic acid, phytic acid, ferric chloride hexahydrate, bacterial cellulose nanofiber dispersion, and ammonium fluorotitanate in step s2 is 0.3:100:(2~6):(1~3):(0.5~1):(0.5~2.5):(5~15).

5. The method for preparing a high-temperature resistant and flame-retardant wood composite board according to claim 2, characterized in that, The bacterial cellulose nanofiber dispersion in step s2 is a bacterial cellulose nanofiber dispersion with a solid content of 1%.

6. The method for preparing a high-temperature resistant and flame-retardant wood composite board according to claim 2, characterized in that, Step s3 involves evacuating to a vacuum level of -0.09 MPa and maintaining it for 30 minutes; then pressurizing to a pressure of 0.6~0.9 MPa and maintaining it for 2~4 hours.

7. The method for preparing a high-temperature resistant and flame-retardant wood composite board according to claim 2, characterized in that, Step s3 involves drying to a target moisture content of 12%.

8. The method for preparing a high-temperature resistant and flame-retardant wood composite board according to claim 2, characterized in that, The mass ratio of phenolic resin adhesive to trimethyl borate in step s4 is 100:(3~7).

9. The method for preparing a high-temperature resistant and flame-retardant wood composite board according to claim 2, characterized in that, The amount of modified adhesive applied in step s5 is 120~160 g / m³. 2 .

10. The method for preparing a high-temperature resistant and flame-retardant wood composite board according to claim 2, characterized in that, The hot pressing process parameters described in step s5 are: temperature 160~175℃, pressure 1.2~1.5MPa, and time 12min.

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