Flame-retardant shaving board and preparation method thereof

Abstract

The invention relates to the technical field of shaving board preparation, and provides a flame-retardant shaving board and a preparation method thereof.The preparation method of the flame-retardant shaving board comprises the following steps that 1, isophorone diisocyanate, polycaprolactone glycol and other raw materials are mixed and react under the protective atmosphere to prepare a prepolymer; 2, reacting the prepolymer with trimethylolpropane, and emulsifying to obtain a modified polyurethane emulsion; and 3, the dried wood shavings and the emulsion are mixed and then subjected to hot press molding, and the flame-retardant shaving board is obtained. The preparation method has the beneficial effects that a chemically synthesized modified monomer reacts with isocyanate through hydroxyl and is chemically bonded into a polyurethane adhesive, the migration problem of various additives in a traditional physical adding mode is avoided, and the flame retardance, the antibacterial property and the water resistance of the prepared shaving board are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of particleboard preparation, and in particular to a flame-retardant particleboard and a preparation method thereof. Background Art

[0002] With the rapid development of building decoration and furniture manufacturing industries, particleboard has been widely used as an economical and environmentally friendly man-made board.

[0003] However, traditional particleboard has significant deficiencies in flame retardancy, severely limiting its application in areas with stringent fire protection requirements, such as public spaces and high-rise buildings. Currently, the industry primarily improves particleboard's flame retardancy by physically adding flame retardants. Commonly used flame retardants include inorganic flame retardants such as aluminum hydroxide and ammonium phosphate, as well as organic flame retardants such as halogen and phosphorus-based flame retardants. While these traditional methods can improve the material's flame retardancy to a certain extent, they suffer from numerous technical drawbacks. First, physically added flame retardants have poor compatibility with the base material and are prone to migration and precipitation during processing and use, which not only affects the durability of the flame retardant effect but also leads to a decrease in the material's mechanical properties. Second, achieving the desired flame retardant effect often requires the addition of large amounts of flame retardants, which significantly increases material costs and affects the board's processing performance. Third, existing technologies struggle to balance flame retardancy with other functional properties, such as antibacterial and water-resistant properties. Furthermore, some flame retardants release toxic gases at high temperatures, posing a safety hazard.

[0004] Therefore, the development of a new particleboard preparation technology with long-lasting flame retardancy, excellent comprehensive performance and environmental protection has important practical significance and application value. Summary of the Invention

[0005] The present invention provides a flame retardant particle board and a preparation method thereof, which solves the defects in the related art.

[0006] The technical solutions of the present invention are as follows: A method for preparing a flame retardant particleboard comprises the following steps: Step 1: Under a protective atmosphere, isophorone diisocyanate, polycaprolactone diol, 1,4-butanediol, dimethylolpropionic acid, modified monomer, and N,N-dimethylacetamide are mixed and stirred evenly. The temperature is raised to 80-90°C, and dibutyltin dilaurate is slowly added dropwise. After the addition is complete, the reaction is continued for 2-3 hours to obtain a prepolymer; Step 2: Mix the prepolymer with trimethylolpropane, react at 80-90°C for 1-2 hours, cool to 40°C, add acetone to adjust the viscosity, then add triethylamine and stir for 5-10 minutes. Then, slowly add deionized water under high-speed stirring, emulsify for 30-40 minutes, and remove acetone by vacuum distillation to obtain a modified polyurethane emulsion; Step 3: Use a drum dryer to reduce the moisture content of the wood chips to 2-6%, mix it with the polyurethane emulsion, and then send it to the paving machine for laying. After pre-pressing, hot pressing and curing, cooling and shaping, a flame-retardant particleboard is obtained.

[0007] More optimally, the prepolymer raw materials include the following components: by weight, 50-60 parts of isophorone diisocyanate, 30-40 parts of polycaprolactone diol, 3-5 parts of 1,4-butanediol, 5-8 parts of dihydroxymethylpropionic acid, 6-8 parts of modified monomers, 40-60 parts of N,N-dimethylacetamide, and 0.1-0.3 parts of dibutyltin dilaurate.

[0008] More optimally, the modified polyurethane emulsion comprises the following components: 100-120 parts by weight of prepolymer, 3-5 parts of trimethylolpropane, and 5-8 parts of triethylamine; the viscosity of the modified polyurethane emulsion at 25° C. is 800-1500 mPa.s.

[0009] More optimally, the mass ratio of the wood chips to the polyurethane emulsion is 10:1; the process parameters of the hot pressing are: temperature 150-170°C, pressure 2.5-4.0 MPa, and time 20-30 s / mm.

[0010] More optimally, the preparation process of the modified monomer is: S1: Mix 1-aminohydantoin hydrochloride with deionized water, adjust the pH to neutral, remove the deionized water by rotary evaporation, add hot ethanol, filter, dry, mix with 3,5-dihydroxyformaldehyde and ethanol, add glacial acetic acid dropwise, increase the temperature to 80-90°C, and reflux for 1-2 hours to obtain intermediate A; S2: Under a protective atmosphere, intermediate A, 18-crown-6, and acetone were mixed and stirred for 30-40 minutes. Pentafluorobenzyl bromide and potassium carbonate were then added in sequence. The mixture was stirred at room temperature for 4 days. After the reaction, the acetone was removed by rotary evaporation. The mixture was extracted, dried, and crystallized. The mixture was transferred to dimethylformamide and stirred evenly. Sodium hypochlorite solution was slowly added dropwise. After the addition was complete, the mixture was reacted for 1-2 minutes to obtain intermediate B. S3: (1) Dissolve the intermediate B in dimethylformamide, add sodium azide, reflux at 60-70°C for 5-6 hours, then stir at room temperature overnight, extract and dry to obtain an azide compound; (2) Under a protective atmosphere, mix the azide compound with dimethylformamide, then add pentamethyldiethylenetriamine, cuprous bromide and propargyl alcohol in sequence, stir at room temperature overnight, and post-treat to obtain a modified monomer.

[0011] In the scheme, aminohydantoin hydrochloride is converted to a free base form by adjusting the pH to neutrality to increase its nucleophilicity. It then undergoes a nucleophilic addition-elimination reaction with the aldehyde group of 3,5-dihydroxyformaldehyde to obtain intermediate A. The specific synthesis process is shown below:

[0012] More optimally, the intermediate A raw material includes the following components: by weight, 13-15 parts of 1-aminohydantoin hydrochloride, 100-120 parts of deionized water, 12-13 parts of 3,5-dihydroxyformaldehyde, 150-200 parts of ethanol, and 0.6-0.8 parts of glacial acetic acid.

[0013] In the scheme, 18-crown-6 complexes with potassium ions in potassium carbonate to increase the free concentration of carbonate ions and enhance their alkalinity. Subsequently, the hydroxyl group of intermediate A is deprotonated under alkaline conditions to form an oxygen anion, which attacks the benzyl carbon of pentafluorobenzyl bromide to form an ether bond. Sodium hypochlorite then undergoes electrophilic chlorination. The specific synthesis process is shown below:

[0014] More optimally, the intermediate B raw material includes the following components: by weight, 20-22 parts of intermediate A, 2-5 parts of 18-crown-6, 200-250 parts of acetone, 24-25 parts of fluorobenzyl bromide, 27-30 parts of potassium carbonate, 3-4 parts of sodium hypochlorite solution, and 100-120 parts of dimethylformamide; wherein the concentration of the sodium hypochlorite solution is 10wt%-15wt%.

[0015] In the scheme, benzyl bromide in intermediate B undergoes an SN2 reaction with sodium azide to generate benzyl azide, which then reacts with propargyl alcohol under Cu(I) catalysis to form a ring. The specific synthesis process is as follows:

[0016] More optimally, the azide compound raw material includes the following components: by weight, 30-32 parts of intermediate B, 150-200 parts of dimethylformamide, and 7-8 parts of sodium azide; the modified monomer raw material includes the following components: by weight, 35-38 parts of azide compound, 150-200 parts of dimethylformamide, 2-3 parts of pentamethyldiethylenetriamine, 0.7-0.8 parts of cuprous bromide, and 6-8 parts of propargyl alcohol.

[0017] The working principle and beneficial effects of the present invention are: The chemically synthesized modified monomer of the present invention reacts with isocyanate via hydroxyl groups and is chemically bonded to the polyurethane adhesive, thus avoiding the migration problem of various additives in traditional physical addition methods and effectively improving the flame retardancy, antibacterial properties, and water resistance of the resulting particleboard. The details are as follows: First: In the scheme, the fluorine and nitrogen elements contained in the modified monomer inhibit combustion through the synergistic effect of the gas phase and the condensed phase; among them, the nitrogen element promotes carbonization, isolating oxygen and heat; the fluorine element releases free radical scavengers to interrupt the chain reaction; and the non-polar properties of the CF bond in the modified monomer can effectively improve the waterproof properties of the material and broaden the application scenarios of the product.

[0018] Second: In the scheme, the N-halamine structure contained in the modified monomer has good antibacterial effect. When it comes into contact with bacteria, the N-Cl bond will release chloride ions. These active chlorine components can oxidize and destroy the lipids and proteins on the bacterial cell membrane, causing damage to the membrane structure and increased permeability; at the same time, they can also attack the enzyme system and genetic material inside the bacteria, inactivating key enzymes and interfering with DNA / RNA replication; effectively enhancing the antibacterial properties of the material. DETAILED DESCRIPTION

[0019] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0020] Example 1: A method for preparing a flame-retardant particleboard, comprising the following steps: Step 1: Under a protective atmosphere, 50 parts of isophorone diisocyanate, 30 parts of polycaprolactone diol, 3 parts of 1,4-butanediol, 5 parts of dimethylolpropionic acid, 6 parts of modified monomer, and 40 parts of N,N-dimethylacetamide were mixed and stirred evenly. The temperature was raised to 80°C, and 0.1 parts of dibutyltin dilaurate were slowly added dropwise. After the addition was completed, the reaction was continued for 2 hours to obtain a prepolymer; Step 2: 100 parts of the prepolymer were mixed with 3 parts of trimethylolpropane, reacted at 80°C for 1 hour, cooled to 40°C, acetone was added to adjust the viscosity, and then 5 parts of triethylamine were added and stirred for 5 minutes. After that, deionized water was slowly added under high-speed stirring, emulsified for 30 minutes, and acetone was removed by vacuum distillation to obtain a modified polyurethane emulsion (viscosity at 25°C was 800 mPa.s); Step 3: Use a drum dryer to reduce the moisture content of 100 parts of wood chips to 2%, mix it with 10 parts of polyurethane emulsion, and then send it to the paving machine for paving. After pre-pressing, hot pressing and curing (temperature 150°C, pressure 2.5MPa, time 20s / mm), cooling and shaping, the flame-retardant particleboard is obtained; Wherein, the preparation process of the modified monomer is: S1: 13 parts of 1-aminohydantoin hydrochloride were mixed with 100 parts of deionized water, the pH was adjusted to neutral, the deionized water was removed by rotary evaporation, hot ethanol was added, the mixture was filtered, and after drying, 12 parts of 3,5-dihydroxyformaldehyde and 150 parts of ethanol were mixed, 0.6 parts of glacial acetic acid was added dropwise, the temperature was raised to 80°C, and the reaction was refluxed for 1 hour to obtain intermediate A; S2: Under protective atmosphere, 20 parts of intermediate A, 2 parts of 18-crown-6, and 200 parts of acetone were mixed and stirred for 30 minutes. Then, 24 parts of pentafluorobenzyl bromide and 27 parts of potassium carbonate were added in sequence. The mixture was stirred at room temperature for 4 days. After the reaction, the acetone was removed by rotary evaporation, and the intermediate B was obtained by extraction, drying, and crystallization. S3: (1) Dissolve 30 parts of intermediate B in 150 parts of dimethylformamide, add 7 parts of sodium azide, reflux at 60°C for 5 hours, then stir at room temperature overnight, extract and dry to obtain an azide compound; (2) Under a protective atmosphere, mix 35 parts of the azide compound with 150 parts of dimethylformamide, then add 2 parts of pentamethyldiethylenetriamine, 0.7 parts of cuprous bromide and 6 parts of propargyl alcohol in sequence, stir at room temperature overnight, and post-treat to obtain intermediate C; S4: 40 parts of intermediate C were added to 200 parts of dimethylformamide, stirred evenly, and 8 parts of sodium hypochlorite solution (concentration of 10 wt%) were slowly added dropwise. After the addition was completed, the mixture was reacted for 5 minutes to obtain a modified monomer.

[0021] Example 2: A method for preparing a flame-retardant particleboard, comprising the following steps: Step 1: Under a protective atmosphere, 60 parts of isophorone diisocyanate, 40 parts of polycaprolactone diol, 5 parts of 1,4-butanediol, 8 parts of dimethylolpropionic acid, 8 parts of modified monomer, and 60 parts of N,N-dimethylacetamide were mixed and stirred evenly. The temperature was raised to 90°C, and 0.3 parts of dibutyltin dilaurate were slowly added dropwise. After the addition was completed, the reaction was continued for 3 hours to obtain a prepolymer; Step 2: 120 parts of the prepolymer were mixed with 5 parts of trimethylolpropane, reacted at 90°C for 2 hours, cooled to 40°C, acetone was added to adjust the viscosity, and then 8 parts of triethylamine were added and stirred for 10 minutes. After that, deionized water was slowly added under high-speed stirring, emulsified for 40 minutes, and acetone was removed by vacuum distillation to obtain a modified polyurethane emulsion (viscosity of 1500 mPa.s at 25°C); Step 3: Use a drum dryer to reduce the moisture content of 100 parts of wood chips to 6%, mix it with 10 parts of polyurethane emulsion, and send it to the paving machine for paving. After pre-pressing, hot pressing and curing (temperature 170°C, pressure 4.0MPa, time 30s / mm), cool and shape it to obtain flame-retardant particleboard; Wherein, the preparation process of the modified monomer is: S1: 15 parts of 1-aminohydantoin hydrochloride were mixed with 120 parts of deionized water, the pH was adjusted to neutral, the deionized water was removed by rotary evaporation, hot ethanol was added, the mixture was filtered, and after drying, 13 parts of 3,5-dihydroxyformaldehyde and 200 parts of ethanol were mixed, 0.8 parts of glacial acetic acid was added dropwise, the temperature was raised to 90°C, and the reaction was refluxed for 2 hours to obtain intermediate A; S2: Under protective atmosphere, 22 parts of intermediate A, 5 parts of 18-crown-6, and 250 parts of acetone were mixed and stirred for 40 minutes. Then, 25 parts of pentafluorobenzyl bromide and 30 parts of potassium carbonate were added in sequence. The mixture was stirred at room temperature for 4 days. After the reaction, the acetone was removed by rotary evaporation, and the intermediate B was obtained by extraction, drying, and crystallization. S3: (1) Dissolve 32 parts of intermediate B in 200 parts of dimethylformamide, add 8 parts of sodium azide, reflux at 70°C for 6 hours, then stir at room temperature overnight, extract and dry to obtain an azide compound; (2) Under a protective atmosphere, mix 38 parts of the azide compound with 200 parts of dimethylformamide, then add 3 parts of pentamethyldiethylenetriamine, 0.8 parts of cuprous bromide and 8 parts of propargyl alcohol in sequence, stir at room temperature overnight, and post-treat to obtain intermediate C; S4: 45 parts of intermediate C were added to 250 parts of dimethylformamide, stirred evenly, and 10 parts of sodium hypochlorite solution (concentration of 15 wt%) were slowly added dropwise. After the addition was completed, the mixture was reacted for 8 minutes to obtain a modified monomer.

[0022] Example 3: A method for preparing a flame-retardant particleboard, comprising the following steps: Step 1: Under a protective atmosphere, 55 parts of isophorone diisocyanate, 35 parts of polycaprolactone diol, 4 parts of 1,4-butanediol, 6.5 parts of dimethylolpropionic acid, 7 parts of modified monomer, and 50 parts of N,N-dimethylacetamide were mixed and stirred evenly. The temperature was raised to 85°C, and 0.2 parts of dibutyltin dilaurate were slowly added dropwise. After the addition was completed, the reaction was continued for 2.5 hours to obtain a prepolymer; Step 2: 110 parts of the prepolymer were mixed with 4 parts of trimethylolpropane, reacted at 85°C for 1.5 hours, cooled to 40°C, acetone was added to adjust the viscosity, and then 6.5 parts of triethylamine were added and stirred for 7.5 minutes. Deionized water was then slowly added under high-speed stirring, emulsified for 35 minutes, and acetone was removed by vacuum distillation to obtain a modified polyurethane emulsion (viscosity of 1150 mPa.s at 25°C); Step 3: Use a drum dryer to reduce the moisture content of 100 parts of wood chips to 4%, mix it with 10 parts of polyurethane emulsion, and then send it to the paving machine for paving. After pre-pressing, hot pressing and curing (temperature 160°C, pressure 3.25MPa, time 25s / mm), cooling and shaping, the flame-retardant particleboard is obtained; Wherein, the preparation process of the modified monomer is: S1: 14 parts of 1-aminohydantoin hydrochloride were mixed with 110 parts of deionized water, the pH was adjusted to neutral, the deionized water was removed by rotary evaporation, hot ethanol was added, the mixture was filtered, and after drying, 12.5 parts of 3,5-dihydroxyformaldehyde and 175 parts of ethanol were mixed, 0.7 parts of glacial acetic acid was added dropwise, the temperature was raised to 85°C, and the reaction was refluxed for 1.5 hours to obtain intermediate A; S2: Under protective atmosphere, 21 parts of intermediate A, 3.5 parts of 18-crown-6, and 225 parts of acetone were mixed and stirred for 35 minutes. Then, 24.5 parts of pentafluorobenzyl bromide and 28.5 parts of potassium carbonate were added in sequence. The mixture was stirred at room temperature for 4 days. After the reaction, the acetone was removed by rotary evaporation, and the intermediate B was obtained by extraction, drying, and crystallization. S3: (1) Dissolve 31 parts of intermediate B in 175 parts of dimethylformamide, add 7.5 parts of sodium azide, reflux at 65°C for 5.5 hours, then stir at room temperature overnight, extract and dry to obtain an azide compound; (2) Under a protective atmosphere, mix 36.5 parts of the azide compound with 175 parts of dimethylformamide, then add 2.5 parts of pentamethyldiethylenetriamine, 0.75 parts of cuprous bromide and 7 parts of propargyl alcohol in sequence, stir at room temperature overnight, and post-treat to obtain intermediate C; S4: 42.5 parts of intermediate C were added to 225 parts of dimethylformamide, stirred evenly, and 9 parts of sodium hypochlorite solution (concentration of 12.5 wt%) were slowly added dropwise. After the addition was complete, the mixture was reacted for 6.5 minutes to obtain a modified monomer.

[0023] Comparative Example 1: No modifying monomer was added, and the rest was the same as Example 3, specifically as follows: Step 1: Under a protective atmosphere, 55 parts of isophorone diisocyanate, 35 parts of polycaprolactone diol, 4 parts of 1,4-butanediol, 6.5 parts of dimethylolpropionic acid, and 50 parts of N,N-dimethylacetamide were mixed and stirred evenly. The temperature was raised to 85°C, and 0.2 parts of dibutyltin dilaurate were slowly added dropwise. After the addition was completed, the reaction was continued for 2.5 hours to obtain a prepolymer; Step 2: 110 parts of the prepolymer were mixed with 4 parts of trimethylolpropane, reacted at 85°C for 1.5 hours, cooled to 40°C, acetone was added to adjust the viscosity, and then 6.5 parts of triethylamine were added and stirred for 7.5 minutes. Deionized water was then slowly added under high-speed stirring, emulsified for 35 minutes, and acetone was removed by vacuum distillation to obtain a modified polyurethane emulsion (viscosity of 1150 mPa.s at 25°C); Step 3: Use a drum dryer to reduce the moisture content of 100 parts of wood chips to 4%, mix it with 10 parts of polyurethane emulsion, and send it to the paving machine for paving. After pre-pressing, hot press curing (temperature 160°C, pressure 3.25MPa, time 25s / mm), cool and shape it to obtain flame-retardant particleboard.

[0024] Comparative Example 2: While not adding the modified monomer, a flame retardant (magnesium oxide inorganic flame retardant) and an antibacterial agent (nano zinc oxide) were introduced separately. The rest was the same as in Example 3, as follows: Step 1: Under a protective atmosphere, 55 parts of isophorone diisocyanate, 35 parts of polycaprolactone diol, 4 parts of 1,4-butanediol, 6.5 parts of dimethylolpropionic acid, and 50 parts of N,N-dimethylacetamide were mixed and stirred evenly. The temperature was raised to 85°C, and 0.2 parts of dibutyltin dilaurate were slowly added dropwise. After the addition was completed, the reaction was continued for 2.5 hours to obtain a prepolymer; Step 2: 110 parts of the prepolymer were mixed with 4 parts of trimethylolpropane, reacted at 85°C for 1.5 hours, cooled to 40°C, acetone was added to adjust the viscosity, and then 6.5 parts of triethylamine were added and stirred for 7.5 minutes. Deionized water was then slowly added under high-speed stirring, emulsified for 35 minutes, and acetone was removed by vacuum distillation to obtain a modified polyurethane emulsion (viscosity of 1150 mPa.s at 25°C); Step 3: Use a drum dryer to reduce the moisture content of 100 parts of wood chips to 4%, mix them with 10 parts of polyurethane emulsion, 1-2 parts of flame retardant, and 1-2 parts of antibacterial agent, and send them to the paving machine for paving. After pre-pressing, hot press curing (temperature 160°C, pressure 3.25MPa, time 25s / mm), cool and shape, and obtain flame-retardant particleboard.

[0025] Testing: The high-strength particleboards obtained in the examples and comparative examples were made into standard specimens of 50 mm × 50 mm (thickness 18 mm) and subjected to the following tests: (1) After the surfaces of the standard samples of the examples and comparative examples were disinfected with ethanol and treated with ultraviolet light, they were smeared with Staphylococcus aureus and Escherichia coli at a concentration of 107 CFU / mL, covered with sterile PE film and allowed to stand for 1 hour (25±1°C). The sample surfaces were then rinsed with phosphate buffered saline (PBS), the rinse solution was collected and diluted, and then smeared on nutrient agar (Staphylococcus aureus) or MacConkey agar (Escherichia coli) culture medium. After incubation at 37°C for 24 hours, the number of colonies was counted and the antibacterial rate was calculated; (2) Measure the internal bonding strength in accordance with GB / T17657-2013; before testing, the specimen must be equilibrated in an environment with a temperature of 23±2°C and a relative humidity of 50±5% for more than 48 hours; a vertical tensile test is performed using a universal testing machine, and both sides of the specimen are bonded to a metal fixture using AB glue; during the test, a tensile force is applied vertically at a constant speed (2 mm / min) until the specimen is delaminated and damaged; and the internal bonding strength is calculated; (3) Measure the limiting oxygen index in accordance with GB / T 2406.1-2008.

[0026] The obtained data are shown in Table 1 below: Table 1

[0027] Conclusion: The flame-retardant particleboard and its preparation method provided by the present invention significantly improve the flame retardancy, antibacterial properties, and mechanical properties of the particleboard by introducing chemically bonded modified monomers. Test data from Examples 1-3 show that the limiting oxygen index reaches 34%, 33%, and 35%, respectively, and the antibacterial rates against Escherichia coli and Staphylococcus aureus exceed 95%, with Example 3 achieving antibacterial rates of 96.6% and 97.3%, respectively. Furthermore, the internal bonding strengths are 1.25 MPa, 1.29 MPa, and 1.32 MPa, respectively, demonstrating that this technical solution offers significant advantages in improving the overall performance of the material.

[0028] Comparative Example 1, which lacks the modified monomer, exhibits a limiting oxygen index of only 25%, with little improvement in antibacterial efficiency (approximately 10%-12%) and a decrease in internal bonding strength to 0.69 MPa. This demonstrates that the introduction of the modified monomer plays a key role in improving flame retardancy, antibacterial properties, and interfacial bonding. The fluorine and nitrogen elements contained in the modified monomer effectively inhibit combustion through synergistic effects in the gas and condensed phases, while the N-halamine structure releases chloride ions to destroy bacterial cell membranes, achieving a highly effective bactericidal effect.

[0029] Comparative Example 2, rather than employing a chemical bonding modification strategy, conducted a comparative experiment by physically adding magnesium oxide flame retardants and antimicrobial agents. The results showed a limiting oxygen index of 29%, with an antimicrobial rate close to that of the examples. However, the internal bonding strength was significantly lower (only 0.42 MPa). This suggests that while physical addition can provide flame retardancy and antimicrobial properties to a certain extent, the lack of chemical bonding between the additive and the matrix results in poor interfacial compatibility, which compromises the material's mechanical properties. Furthermore, the large addition of flame retardants and antimicrobial agents can lead to increased costs and deterioration in processing performance, limiting their practical application.

[0030] In summary, the success of this invention lies in achieving simultaneous improvements in flame retardancy, antibacterial properties, and water resistance without sacrificing mechanical properties through chemical synthesis and bonding of modified monomers. This method not only overcomes the common problems of functional migration, poor compatibility, and unstable performance seen in traditional physical addition methods, but also, through molecular structure design optimization, fully leverages the synergistic effects of fluorine, nitrogen, and N-halamine structures, providing a practical and feasible technical path for the development of high-performance, environmentally friendly particleboards.

[0031] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a flame retardant particleboard, characterized in that: The following steps are involved: Step 1: Under a protective atmosphere, isophorone diisocyanate, polycaprolactone diol, 1,4-butanediol, dimethylolpropionic acid, modified monomer, and N,N-dimethylacetamide are mixed and stirred evenly. The temperature is raised to 80-90°C, and dibutyltin dilaurate is slowly added dropwise. After the addition is complete, the reaction is continued for 2-3 hours to obtain a prepolymer; Step 2: Mix the prepolymer with trimethylolpropane, react at 80-90°C for 1-2 hours, cool to 40°C, add acetone to adjust the viscosity, then add triethylamine and stir for 5-10 minutes. Then, slowly add deionized water under high-speed stirring, emulsify for 30-40 minutes, and remove acetone by vacuum distillation to obtain a modified polyurethane emulsion; Step 3: Use a drum dryer to reduce the moisture content of the wood chips to 2%-6%, mix it with the polyurethane emulsion, and then send it to the paving machine for paving. After pre-pressing, hot pressing and curing, cooling and shaping, a flame-retardant particleboard is obtained.

2. The method for preparing a flame retardant particleboard according to claim 1, wherein: The prepolymer raw material includes the following components: by weight, 50-60 parts of isophorone diisocyanate, 30-40 parts of polycaprolactone diol, 3-5 parts of 1,4-butanediol, 5-8 parts of dihydroxymethylpropionic acid, 6-8 parts of modified monomer, 40-60 parts of N,N-dimethylacetamide, and 0.1-0.3 parts of dibutyltin dilaurate.

3. The method for preparing a flame retardant particleboard according to claim 1, wherein: The modified polyurethane emulsion comprises the following components: 100-120 parts by weight of prepolymer, 3-5 parts of trimethylolpropane, and 5-8 parts of triethylamine; the viscosity of the modified polyurethane emulsion at 25° C. is 800-1500 mPa.s.

4. The method for preparing a flame-retardant particleboard according to claim 1, wherein: The mass ratio of the wood chips to the polyurethane emulsion is 10:1; the process parameters of the hot pressing are: temperature 150-170° C., pressure 2.5-4.0 MPa, and time 20-30 s / mm.

5. The method for preparing a flame retardant particleboard according to claim 1, wherein: The preparation process of the modified monomer is: S1: Mix 1-aminohydantoin hydrochloride with deionized water, adjust the pH to neutral, remove the deionized water by rotary evaporation, add hot ethanol, filter, dry, mix with 3,5-dihydroxyformaldehyde and ethanol, add glacial acetic acid dropwise, increase the temperature to 80-90°C, and reflux for 1-2 hours to obtain intermediate A; S2: Under a protective atmosphere, intermediate A, 18-crown-6, and acetone were mixed and stirred for 30-40 minutes. Pentafluorobenzyl bromide and potassium carbonate were then added in sequence. The mixture was stirred at room temperature for 4 days. After the reaction, the acetone was removed by rotary evaporation. The mixture was extracted, dried, and crystallized. The mixture was transferred to dimethylformamide and stirred evenly. Sodium hypochlorite solution was slowly added dropwise. After the addition was complete, the mixture was reacted for 1-2 minutes to obtain intermediate B. S3: (1) Dissolve the intermediate B in dimethylformamide, add sodium azide, reflux at 60-70°C for 5-6 hours, then stir at room temperature overnight, extract and dry to obtain an azide compound; (2) Under a protective atmosphere, mix the azide compound with dimethylformamide, then add pentamethyldiethylenetriamine, cuprous bromide and propargyl alcohol in sequence, stir at room temperature overnight, and post-treat to obtain a modified monomer.

6. The method for preparing a flame-retardant particleboard according to claim 5, characterized in that: The intermediate A raw material includes the following components: by weight, 13-15 parts of 1-aminohydantoin hydrochloride, 100-120 parts of deionized water, 12-13 parts of 3,5-dihydroxyformaldehyde, 150-200 parts of ethanol, and 0.6-0.8 parts of glacial acetic acid.

7. The method for preparing a flame-retardant particleboard according to claim 5, characterized in that: The intermediate B raw material includes the following components: by weight, 20-22 parts of intermediate A, 2-5 parts of 18-crown-6, 200-250 parts of acetone, 24-25 parts of fluorobenzyl bromide, 27-30 parts of potassium carbonate, 3-4 parts of sodium hypochlorite solution, and 100-120 parts of dimethylformamide; wherein the concentration of the sodium hypochlorite solution is 10wt%-15wt%.

8. The method for preparing a flame-retardant particleboard according to claim 5, characterized in that: The azide compound raw material includes the following components: 30-32 parts of intermediate B, 150-200 parts of dimethylformamide, and 7-8 parts of sodium azide, by weight; the modified monomer raw material includes the following components: 35-38 parts of azide compound, 150-200 parts of dimethylformamide, 2-3 parts of pentamethyldiethylenetriamine, 0.7-0.8 parts of cuprous bromide, and 6-8 parts of propargyl alcohol, by weight.

9. A flame retardant particle board obtained by the method for preparing a flame retardant particle board according to any one of claims 1 to 8.

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