Flame-retardant particle board and method for producing the same
By using chemically synthesized modified monomers bonded to polyurethane adhesives, the problem of insufficient flame retardant properties in traditional particleboard has been solved, achieving simultaneous improvement in flame retardancy, antibacterial properties, and mechanical properties, thus overcoming the shortcomings of physical additive methods.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WENAN COUNTRY HEMIN WOOD-PROCESSING CO LTD
- Filing Date
- 2025-07-01
- Publication Date
- 2026-07-24
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of particleboard preparation technology, specifically to a flame-retardant particleboard and its preparation method. Background Technology
[0002] With the rapid development of the building decoration and furniture manufacturing industries, particleboard, as an economical and environmentally friendly engineered wood product, has been widely used.
[0003] However, traditional particleboard has significant shortcomings in flame retardancy, severely limiting its application in public places and high-rise buildings where fire safety requirements are stringent. Currently, the industry mainly improves the flame retardancy of particleboard 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 halogenated and phosphorus-based flame retardants. While these traditional methods can improve the flame retardancy of materials to some extent, they have several technical drawbacks: First, physically added flame retardants have poor compatibility with the matrix material, easily migrating and precipitating during processing and use, affecting not only the durability of the flame retardant effect but also leading to a decrease in the material's mechanical properties. Second, achieving the ideal flame retardant effect often requires adding large amounts of flame retardant, significantly increasing material costs and affecting the processing performance of the board. Third, existing technologies struggle to simultaneously achieve flame retardancy with other functional properties, such as antibacterial and waterproof properties. Furthermore, some flame retardants release toxic gases at high temperatures, posing safety hazards.
[0004] Therefore, developing a new particleboard preparation technology that is long-lasting in flame retardancy, has excellent overall performance, and is environmentally friendly has significant practical implications and application value. Summary of the Invention
[0005] This invention proposes a flame-retardant particleboard and its preparation method, which solves the defects in related technologies.
[0006] The technical solution of the present invention is as follows: A method for preparing flame-retardant particleboard includes 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℃, and dibutyltin dilaurate is slowly added dropwise. After the addition is complete, the reaction continues for 2-3 hours to obtain the prepolymer. Step 2: Mix the prepolymer with trimethylolpropane and react at 80-90℃ for 1-2 hours. Cool down to 40℃, add acetone to adjust the viscosity, then add triethylamine and stir for 5-10 minutes. Then slowly add deionized water under high-speed stirring and emulsify for 30-40 minutes. Remove acetone by vacuum distillation to obtain the modified polyurethane emulsion. Step 3: Use a drum dryer to reduce the moisture content of the wood chips to 2-6%, mix them with polyurethane emulsion, and then send them to a paving machine for installation. After pre-pressing, hot-press curing and cooling are performed to obtain flame-retardant particleboard.
[0007] More preferably, the prepolymer raw material includes the following components by weight: 50-60 parts isophorone diisocyanate, 30-40 parts polycaprolactone diol, 3-5 parts 1,4-butanediol, 5-8 parts dimethylolpropionic acid, 6-8 parts modified monomer, 40-60 parts N,N-dimethylacetamide, and 0.1-0.3 parts dibutyltin dilaurate.
[0008] More preferably, the modified polyurethane emulsion comprises the following components: by weight, 100-120 parts 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] Ideally, the mass ratio of wood shavings to polyurethane emulsion is 10:1; the hot pressing process parameters are: temperature 150-170℃, pressure 2.5-4.0MPa, and time 20-30s / mm.
[0010] In a more optimized manner, the preparation process of the modified monomer is as follows: 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, raise the temperature to 80-90℃, reflux for 1-2 hours to obtain intermediate A. S2: Under a protective atmosphere, intermediate A, 18-crown-6, and acetone are mixed and stirred for 30-40 min. Then, pentafluorobenzyl bromide and potassium carbonate are added sequentially. The mixture is stirred at room temperature for 4 days. After the reaction is complete, acetone is removed by rotary evaporation, and the mixture is extracted, dried, and crystallized. The crystals are then transferred to dimethylformamide, stirred until homogeneous, and sodium hypochlorite solution is slowly added dropwise. After the addition is complete, the mixture is reacted for 1-2 min to obtain intermediate B. S3: (1) Dissolve intermediate B in dimethylformamide, add sodium azide, reflux at 60-70°C for 5-6 hours, then stir overnight at room temperature, extract and dry to obtain azide compound; (2) Under a protective atmosphere, mix azide compound with dimethylformamide, then add pentamethyldiethylenetriamine, cuprous bromide and propynyl alcohol in sequence, stir overnight at room temperature, and then perform post-treatment to obtain modified monomer.
[0011] In this scheme, aminohydantoin hydrochloride is converted to a free base form by adjusting the pH to neutral, thereby increasing its nucleophilicity. It then undergoes a nucleophilic addition-elimination reaction with the aldehyde group of 3,5-dihydroxyformaldehyde to give intermediate A. The specific synthetic process is shown below:
[0012] More preferably, 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 this scheme, 18-crown-6 complexes with potassium ions in potassium carbonate, increasing the free carbonate concentration and enhancing its basicity. Subsequently, the hydroxyl group of intermediate A is deprotonated under basic conditions to form an oxonium, which attacks the benzylic carbon of pentafluorobenzyl bromide to form an ether bond. Then, sodium hypochlorite undergoes electrophilic chlorination. The specific synthetic process is shown below:
[0014] More preferably, the intermediate B raw material comprises 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 pentafluorobenzyl 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 10-15 wt%.
[0015] In the process, benzyl bromide in intermediate B undergoes an SN2 reaction with sodium azide to generate benzyl azide. Subsequently, the azide reacts with propynyl alcohol under Cu(I) catalysis to form a ring. The specific synthetic process is shown below:
[0016] More preferably, the azide compound raw material comprises the following components: by weight, 30-32 parts intermediate B, 150-200 parts dimethylformamide, and 7-8 parts sodium azide; the modified monomer raw material comprises the following components: by weight, 35-38 parts azide compound, 150-200 parts dimethylformamide, 2-3 parts pentamethyldiethylenetriamine, 0.7-0.8 parts cuprous bromide, and 6-8 parts propynyl alcohol.
[0017] The working principle and beneficial effects of this invention are as follows: The modified monomers synthesized in this invention react with isocyanates via hydroxyl groups and are then chemically bonded to polyurethane adhesives. This avoids the migration problems of various additives in traditional physical addition methods, effectively improving the flame retardant, antibacterial, and water resistance properties of the resulting particleboard. Details are as follows: Firstly, in this scheme, the fluorine and nitrogen elements contained in the modified monomer inhibit combustion through the synergistic effect of the gas phase and condensed phase; among them, nitrogen promotes char formation and isolates oxygen and heat; fluorine releases free radical scavengers, interrupting the chain reaction; and the non-polar nature 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] Secondly, the N-haloamine structure contained in the modified monomer has good antibacterial properties. When it comes into contact with bacteria, the N-Cl bond releases chloride ions. These active chlorine components can oxidize and destroy lipids and proteins on the bacterial cell membrane, leading to membrane structure damage and increased permeability. At the same time, it can also attack the enzyme system and genetic material inside the bacteria, inactivating key enzymes and interfering with DNA / RNA replication, thus effectively enhancing the antibacterial properties of the material. Detailed Implementation
[0019] 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.
[0020] Example 1: A method for preparing flame-retardant particleboard, comprising the following steps: Step 1: Under a protective atmosphere, mix 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, stir until homogeneous, raise the temperature to 80°C, and slowly add 0.1 parts of dibutyltin dilaurate. After the addition is complete, continue the reaction for 2 hours to obtain the prepolymer. Step 2: Mix 100 parts of prepolymer with 3 parts of trimethylolpropane and react at 80°C for 1 hour. Cool down to 40°C, add acetone to adjust the viscosity, then add 5 parts of triethylamine and stir for 5 minutes. Then slowly add deionized water under high-speed stirring and emulsify for 30 minutes. Remove acetone by vacuum distillation to obtain a modified polyurethane emulsion (viscosity at 25°C is 800 mPa·s). Step 3: Use a drum dryer to reduce the moisture content of 100 parts of wood chips to 2%, mix with 10 parts of polyurethane emulsion, and then send to the laying machine for laying. After pre-pressing, hot-press curing (temperature 150℃, pressure 2.5MPa, time 20s / mm), cool and shape to obtain flame-retardant wood chips. The preparation process of the modified monomer is as follows: S1: Mix 13 parts of 1-aminohydantoin hydrochloride with 100 parts of deionized water, adjust the pH to neutral, remove the deionized water by rotary evaporation, add hot ethanol, filter, dry, mix with 12 parts of 3,5-dihydroxyformaldehyde and 150 parts of ethanol, add 0.6 parts of glacial acetic acid dropwise, raise the temperature to 80℃, reflux for 1 h to obtain intermediate A; S2: Under a protective atmosphere, 20 parts of intermediate A, 2 parts of 18-crown-6 and 200 parts of acetone were mixed and stirred for 30 min. 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 was completed, the acetone was removed by rotary evaporation, and the mixture was extracted, dried and crystallized to obtain intermediate B. 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 h, then stir overnight at room temperature, extract and dry to obtain azide compound; (2) Under a protective atmosphere, mix 35 parts of azide compound with 150 parts of dimethylformamide, then add 2 parts of pentamethyldiethylenetriamine, 0.7 parts of cuprous bromide and 6 parts of propynyl alcohol in sequence, stir overnight at room temperature, and then post-process to obtain intermediate C; S4: Add 40 parts of intermediate C to 200 parts of dimethylformamide, stir well, and slowly add 8 parts of sodium hypochlorite solution (concentration of 10wt%). After the addition is complete, react for 5 minutes to obtain the modified monomer.
[0021] Example 2: A method for preparing 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 are mixed and stirred evenly. The temperature is raised to 90°C, and 0.3 parts of dibutyltin dilaurate are slowly added dropwise. After the addition is complete, the reaction continues for 3 hours to obtain the prepolymer. Step 2: Mix 120 parts of prepolymer with 5 parts of trimethylolpropane and react at 90°C for 2 hours. Cool down to 40°C, add acetone to adjust the viscosity, then add 8 parts of triethylamine and stir for 10 minutes. Then slowly add deionized water under high-speed stirring and emulsify for 40 minutes. Remove acetone by vacuum distillation to obtain a modified polyurethane emulsion (viscosity at 25°C is 1500 mPa·s). Step 3: Use a drum dryer to reduce the moisture content of 100 parts of wood chips to 6%, mix with 10 parts of polyurethane emulsion, and then send to the laying machine for laying. After pre-pressing, hot-press curing (temperature 170℃, pressure 4.0MPa, time 30s / mm), cool and shape to obtain flame-retardant wood chips. The preparation process of the modified monomer is as follows: S1: Mix 15 parts of 1-aminohydantoin hydrochloride with 120 parts of deionized water, adjust the pH to neutral, remove the deionized water by rotary evaporation, add hot ethanol, filter, dry, mix with 13 parts of 3,5-dihydroxyformaldehyde and 200 parts of ethanol, add 0.8 parts of glacial acetic acid dropwise, raise the temperature to 90℃, reflux for 2 hours to obtain intermediate A; S2: Under a protective atmosphere, 22 parts of intermediate A, 5 parts of 18-crown-6 and 250 parts of acetone were mixed and stirred for 40 min. 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 was completed, the acetone was removed by rotary evaporation, and the mixture was extracted, dried and crystallized to obtain intermediate B. 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 h, then stir overnight at room temperature, extract and dry to obtain azide compound; (2) Under a protective atmosphere, mix 38 parts of azide compound with 200 parts of dimethylformamide, then add 3 parts of pentamethyldiethylenetriamine, 0.8 parts of cuprous bromide and 8 parts of propynyl alcohol in sequence, stir overnight at room temperature, and then post-process to obtain intermediate C; S4: Add 45 parts of intermediate C to 250 parts of dimethylformamide, stir well, and slowly add 10 parts of sodium hypochlorite solution (concentration of 15wt%). After the addition is complete, react for 8 minutes to obtain the modified monomer.
[0022] Example 3: A method for preparing 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 the prepolymer. Step 2: Mix 110 parts of prepolymer with 4 parts of trimethylolpropane and react at 85°C for 1.5 h. Cool down to 40°C, add acetone to adjust the viscosity, then add 6.5 parts of triethylamine and stir for 7.5 min. Then slowly add deionized water under high-speed stirring and emulsify for 35 min. Remove acetone by vacuum distillation to obtain modified polyurethane emulsion (viscosity at 25°C is 1150 mPa·s). Step 3: Use a drum dryer to reduce the moisture content of 100 parts of wood chips to 4%, mix with 10 parts of polyurethane emulsion, and then send to the laying machine for laying. After pre-pressing, hot-press curing (temperature 160℃, pressure 3.25MPa, time 25s / mm), cool and shape to obtain flame-retardant wood chips. The preparation process of the modified monomer is as follows: S1: Mix 14 parts of 1-aminohydantoin hydrochloride with 110 parts of deionized water, adjust the pH to neutral, remove the deionized water by rotary evaporation, add hot ethanol, filter, dry, mix with 12.5 parts of 3,5-dihydroxyformaldehyde and 175 parts of ethanol, add 0.7 parts of glacial acetic acid dropwise, raise the temperature to 85℃, and reflux for 1.5 h to obtain intermediate A; S2: Under a 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 min. 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 was completed, the acetone was removed by rotary evaporation, and the mixture was extracted, dried and crystallized to obtain intermediate B. 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 h, then stir overnight at room temperature, extract and dry to obtain azide compound; (2) Under a protective atmosphere, mix 36.5 parts of azide compound with 175 parts of dimethylformamide, then add 2.5 parts of pentamethyldiethylenetriamine, 0.75 parts of cuprous bromide and 7 parts of propynyl alcohol in sequence, stir overnight at room temperature, and then post-process to obtain intermediate C; S4: Add 42.5 parts of intermediate C to 225 parts of dimethylformamide, stir well, and slowly add 9 parts of sodium hypochlorite solution (concentration of 12.5 wt%). After the addition is complete, react for 6.5 min to obtain the modified monomer.
[0023] Comparative Example 1: No modified monomer was added; all other aspects were 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 the prepolymer. Step 2: Mix 110 parts of prepolymer with 4 parts of trimethylolpropane and react at 85°C for 1.5 h. Cool down to 40°C, add acetone to adjust the viscosity, then add 6.5 parts of triethylamine and stir for 7.5 min. Then slowly add deionized water under high-speed stirring and emulsify for 35 min. Remove acetone by vacuum distillation to obtain modified polyurethane emulsion (viscosity at 25°C is 1150 mPa·s). Step 3: Use a drum dryer to reduce the moisture content of 100 parts of wood chips to 4%, mix with 10 parts of polyurethane emulsion, and then send to the laying machine for laying. After pre-pressing, hot-press curing (temperature 160℃, pressure 3.25MPa, time 25s / mm), cool and shape to obtain flame-retardant wood chips.
[0024] Comparative Example 2: Without adding the modified monomer, a separate flame retardant (magnesium oxide inorganic flame retardant) and antibacterial agent (nano zinc oxide) were introduced. 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 the prepolymer. Step 2: Mix 110 parts of prepolymer with 4 parts of trimethylolpropane and react at 85°C for 1.5 h. Cool down to 40°C, add acetone to adjust the viscosity, then add 6.5 parts of triethylamine and stir for 7.5 min. Then slowly add deionized water under high-speed stirring and emulsify for 35 min. Remove acetone by vacuum distillation to obtain modified polyurethane emulsion (viscosity at 25°C is 1150 mPa·s). Step 3: Use a drum dryer to reduce the moisture content of 100 parts of wood chips to 4%, mix with 10 parts of polyurethane emulsion, 1-2 parts of flame retardant, and 1-2 parts of antibacterial agent, and then send it to the laying machine for laying. After pre-pressing, it is hot-pressed and cured (temperature 160℃, pressure 3.25MPa, time 25s / mm), cooled and shaped to obtain flame-retardant wood chips.
[0025] Testing: The high-strength particleboard obtained from the examples and comparative examples was made into standard specimens of 50mm × 50mm (18mm thick) and subjected to the following tests: (1) After disinfecting the surface of the standard samples of the examples and comparative examples with ethanol and treating them with ultraviolet light, Staphylococcus aureus and Escherichia coli bacterial suspension with a concentration of 107 CFU / mL were applied to the sample, respectively. The sample was covered with sterile PE film and left to stand for 1 h (25±1℃). Then the sample surface was rinsed with phosphate buffer (PBS). The rinse solution was collected, diluted and spread on nutrient agar (Staphylococcus aureus) or MacConkey agar (Escherichia coli) medium. After incubation at 37℃ for 24 h, the number of colonies was counted and the antibacterial rate was calculated. (2) The internal bond strength shall be measured in accordance with GB / T17657-2013. Before the test, the sample shall be equilibrated for more than 48 hours in an environment with a temperature of 23±2℃ and a relative humidity of 50±5%. A universal testing machine shall be used to perform a vertical tensile test. AB glue shall be used to bond the two sides of the sample to the metal clamp. During the test, a constant tensile force (2mm / min) shall be applied vertically until the sample delaminates and fails. The internal bond strength shall be calculated. (3) In accordance with GB / T2406.1 In 2008, the limiting oxygen index was measured.
[0026] The obtained data is shown in the table below: Table 1
[0027] Conclusion: The flame-retardant particleboard and its preparation method provided by this invention significantly improve the flame-retardant, antibacterial, 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* both exceed 95%, with Example 3 achieving antibacterial rates of 96.6% and 97.3%, respectively. Simultaneously, the internal bond strengths are 1.25 MPa, 1.29 MPa, and 1.32 MPa, respectively, indicating that this technical solution has significant advantages in improving the overall performance of the material.
[0028] Comparative Example 1, without the addition of modified monomers, had a limiting oxygen index of only 25%, almost no improvement in antibacterial rate (approximately 10%-12%), and its internal bond strength also decreased to 0.69 MPa. This indicates that the introduction of modified monomers plays a crucial role in improving flame retardancy, antibacterial properties, and interfacial bonding. The fluorine and nitrogen elements contained in the modified monomers effectively inhibit the combustion process through the synergistic effect of the gas and condensed phases, while the N-haloamine structure achieves a highly efficient bactericidal effect by releasing chloride ions to disrupt bacterial cell membranes.
[0029] Comparative Example 2 did not employ a chemical bonding modification strategy. Instead, it used a physical addition of magnesium oxide flame retardant and antibacterial agent for comparative experiments. The results showed that its limiting oxygen index was 29%, and the antibacterial rate was close to that of the example. However, the internal bond strength was significantly lower (only 0.42 MPa). This indicates that although the physical addition method can provide flame retardant and antibacterial functions to some extent, the lack of chemical bonding between the additive and the matrix leads to poor interfacial compatibility, affecting the mechanical properties of the material. Furthermore, the large addition of flame retardants and antibacterial agents may lead to increased costs and deteriorated processing performance, limiting its practical application value.
[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 the chemical synthesis and bonding of modified monomers. This method not only overcomes common problems in traditional physical additive methods such as functional migration, poor compatibility, and performance instability, but also fully leverages the synergistic effects of fluorine, nitrogen, and N-haloamine structures through optimized molecular structure design, providing a practical and feasible technical path for the development of high-performance environmentally friendly particleboard.
[0031] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing flame-retardant particleboard, characterized in that: Includes 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℃, and dibutyltin dilaurate is slowly added dropwise. After the addition is complete, the reaction continues for 2-3 hours to obtain the prepolymer. Step 2: Mix the prepolymer with trimethylolpropane and react at 80-90℃ for 1-2 hours. Cool down to 40℃, add acetone to adjust the viscosity, then add triethylamine and stir for 5-10 minutes. Then slowly add deionized water under high-speed stirring and emulsify for 30-40 minutes. Remove acetone by vacuum distillation to obtain the modified polyurethane emulsion. Step 3: Use a drum dryer to reduce the moisture content of the wood chips to 2-6%, mix them with polyurethane emulsion, and then send them to a paving machine for installation. After pre-pressing, hot-press curing and cooling are performed to obtain flame-retardant particleboard. The preparation process of the modified monomer is as follows: 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, raise the temperature to 80-90℃, reflux for 1-2 hours to obtain intermediate A. S2: Under a protective atmosphere, intermediate A, 18-crown-6, and acetone are mixed and stirred for 30-40 min. Then, pentafluorobenzyl bromide and potassium carbonate are added sequentially. The mixture is stirred at room temperature for 4 days. After the reaction is complete, acetone is removed by rotary evaporation, and the mixture is extracted, dried, and crystallized. The crystals are then transferred to dimethylformamide, stirred until homogeneous, and sodium hypochlorite solution is slowly added dropwise. After the addition is complete, the mixture is reacted for 1-2 min to obtain intermediate B. S3: (1) Dissolve intermediate B in dimethylformamide, add sodium azide, reflux at 60-70°C for 5-6 hours, then stir overnight at room temperature, extract and dry to obtain azide compound; (2) Under a protective atmosphere, mix azide compound with dimethylformamide, then add pentamethyldiethylenetriamine, cuprous bromide and propynyl alcohol in sequence, stir overnight at room temperature, and then perform post-treatment to obtain modified monomer.
2. The method for preparing a flame-retardant particleboard according to claim 1, characterized in that: The prepolymer raw material includes the following components by weight: 50-60 parts isophorone diisocyanate, 30-40 parts polycaprolactone diol, 3-5 parts 1,4-butanediol, 5-8 parts dimethylolpropionic acid, 6-8 parts modified monomer, 40-60 parts N,N-dimethylacetamide, and 0.1-0.3 parts dibutyltin dilaurate.
3. The method for preparing a flame-retardant particleboard according to claim 1, characterized in that: The modified polyurethane emulsion comprises the following components: by weight, 100-120 parts prepolymer, 3-5 parts trimethylolpropane, and 5-8 parts 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, characterized in that: The mass ratio of wood shavings to polyurethane emulsion is 10:1; the hot pressing process parameters are: temperature 150-170℃, pressure 2.5-4.0MPa, and time 20-30s / mm.
5. The method for preparing a flame-retardant particleboard according to claim 1, characterized in that: The intermediate A raw material comprises 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.
6. The method for preparing a flame-retardant particleboard according to claim 1, characterized in that: The intermediate B raw material comprises the following components by weight: 20-22 parts intermediate A, 2-5 parts 18-crown-6, 200-250 parts acetone, 24-25 parts pentafluorobenzyl bromide, 27-30 parts potassium carbonate, 3-4 parts sodium hypochlorite solution, and 100-120 parts dimethylformamide; wherein the concentration of the sodium hypochlorite solution is 10-15 wt%.
7. The method for preparing a flame-retardant particleboard according to claim 1, characterized in that: The azide compound raw material comprises the following components: by weight, 30-32 parts intermediate B, 150-200 parts dimethylformamide, and 7-8 parts sodium azide; the modified monomer raw material comprises the following components: by weight, 35-38 parts azide compound, 150-200 parts dimethylformamide, 2-3 parts pentamethyldiethylenetriamine, 0.7-0.8 parts cuprous bromide, and 6-8 parts propynyl alcohol.
8. The flame-retardant particleboard obtained by the method for preparing a flame-retardant particleboard according to any one of claims 1-7.