Preparation process of high-performance green flame-retardant plywood

Abstract

The present application relates to a kind of preparation process of high-performance green flame-retardant plywood, it includes: the synthesis of crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS), the preparation of high-temperature pulp adhesive, the preparation of water-based epoxy resin, the preparation of L-Trp-DOPO inorganic phosphorus-containing flame retardant, the preparation of epoxy resin flame-retardant material, the preparation of high-performance green flame-retardant plywood and the like step, the preparation method of esterification reaction, phase inversion method, chemical one-step method, hot-pressing method and the like is creatively combined, the high-performance green flame-retardant plywood prepared has good mechanical properties, excellent flame retardancy and the like advantages, and raw material source is wide, renewable is strong, and the characteristics such as high reactivity, composite green environmental protection concept, in plywood application field widely, its application prospect will be more broad.

Description

Technical Field

[0001] This invention relates to the preparation of a new material, and more particularly to a preparation process for a high-performance, green, fire-retardant plywood. Background Technology

[0002] With the rapid development of the engineered wood products industry, the environmental performance of adhesives has received widespread attention from consumers. Synthetic resin adhesives made from petrochemical products have excellent bonding and water resistance properties. However, some synthetic resins contain substances such as formaldehyde and phenol, which can harm the environment and human health during production, transportation, and use. Developing safe, environmentally friendly adhesives has become a key research focus and future development trend in adhesives. As a result, environmentally friendly and renewable plant protein adhesives have gained attention and favor from the industry. Furthermore, wood is flammable, and the use of engineered wood products in building decoration poses a fire hazard. With the implementation of relevant regulations and standards for flame-retardant materials in my country, higher requirements have been placed on flame-retardant materials, making the flame-retardant performance of engineered wood products one of the main factors for consumers' choices.

[0003] This invention utilizes soybean protein to prepare green flame-retardant plywood. High-temperature soybean meal is used instead of low-temperature soybean meal to prepare soybean meal adhesive. The thermochemical modification of high-temperature soybean meal can significantly improve the adhesive strength and water resistance of the adhesive. It also has the characteristics of (1) strong regeneration ability and (2) high reactivity, which are in line with the green concept. It can also effectively improve the resistance of soybean meal to normal aging and the storage stability of soybean meal. At the same time, it can effectively reduce the raw material cost of the adhesive. The green flame-retardant plywood made by combining with the new composite flame retardant also has good flame retardancy. This is of positive significance for expanding the application field of green flame-retardant plywood and promoting the application of soybean meal adhesive in the wood industry. Summary of the Invention

[0004] To address the above problems, this invention provides a preparation process for high-performance green fire-retardant plywood.

[0005] The present invention provides a preparation process for high-performance green flame-retardant plywood, comprising the following steps: synthesis of crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS), preparation of high-temperature meal adhesive, preparation of waterborne epoxy resin, preparation of L-Trp-DOPO inorganic phosphorus-containing flame retardant, preparation of epoxy resin flame retardant material, and preparation of high-performance green flame-retardant plywood.

[0006] Among them, step (4) preparation of L-Trp-DOPO inorganic phosphorus flame retardant

[0007] Weigh a certain amount of L-Trp-BS and organophosphorus compound (DOPO) and dissolve them in a three-necked flask containing tetrahydrofuran. Stir the mixture thoroughly and place it in an oil bath. React for a period of time and wash the precipitated dark yellow product with ethanol and deionized water. Dry it overnight in a forced-air oven at a certain temperature to obtain L-Trp-DOPO inorganic phosphorus flame retardant.

[0008] Step (5) Preparation of epoxy resin flame retardant material

[0009] The flame retardant L-Trp-DOPO prepared in step (4) was dissolved in anhydrous ethanol and dispersed in a water bath for a period of time. The epoxy resin obtained in step (3) was added and stirred. Diethylenetriamine was then added to the above mixed solution. Anhydrous ethanol was removed by a vacuum filter. After a period of time, the mixed solution was poured into a preheated template and defoamed in an oven. The sample was placed in the oven to cure for a period of time, and then the oven was switched to programmed temperature rise for storage.

[0010] Preferably, step (1) involves the synthesis of the crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS).

[0011] 2,5-furandicarboxylic acid (FDCA) and N-hydroxysuccinimide (NHS) were dissolved in dimethyl sulfoxide (DMSO). 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) was added to the above solution. The mixture was stirred at a certain temperature. After the reaction was completed, the dimethyl sulfoxide (DMSO) was washed away by extraction. The reaction product was purified by column chromatography and finally dried in a vacuum drying oven at a certain temperature for later use.

[0012] Step (2) Preparation of high-temperature meal adhesive

[0013] Take the flake soybean meal and put it into a pulverizer to pulverize it and pass it through a sieve to obtain high-temperature soybean meal powder. Add water to the crosslinking agent modifier furan dicarboxylic acid-NHS active ester (FDCA-NHS) solution obtained in step (1), stir evenly at room temperature, adjust the solid content of the solvent, and then add soybean meal powder. Stir at room temperature to form a uniform soybean meal adhesive without particulate matter, and obtain high-temperature soybean meal adhesive.

[0014] Step (3) Preparation of waterborne epoxy resin

[0015] Epoxy resin E-31 and polyethylene glycol (PEG) were added to a three-necked flask equipped with a stirrer and a condenser. The mixture was heated until it melted and stirred until homogeneous. Potassium persulfate was dissolved in water and slowly added dropwise to the flask. After mixing until homogeneous, the temperature was raised to obtain a nonionic epoxy emulsifier. The temperature was lowered, and epoxy resin E-54 was added. The mixture was stirred until homogeneous with the epoxy emulsifier. Then, distilled water was slowly added dropwise at a certain stirring speed. When the viscosity of the system suddenly decreased, the system changed from W / O to O / W. After the water was added, the mixture was stirred for a period of time to obtain an aqueous epoxy resin.

[0016] Step (4) Preparation of L-Trp-DOPO inorganic phosphorus-containing flame retardant

[0017] Weigh a certain amount of L-Trp-BS and organophosphorus compound (DOPO) and dissolve them in a three-necked flask containing tetrahydrofuran. Stir the mixture thoroughly and place it in an oil bath. React for a period of time and wash the precipitated dark yellow product with ethanol and deionized water. Dry it overnight in a forced-air oven at a certain temperature to obtain L-Trp-DOPO inorganic phosphorus flame retardant.

[0018] Step (5) Preparation of epoxy resin flame retardant material

[0019] The flame retardant L-Trp-DOPO prepared in step (4) was dissolved in anhydrous ethanol and dispersed in a water bath for a period of time. The epoxy resin obtained in step (3) was added and stirred. Then, diethylenetriamine was added to the above mixed solution. Anhydrous ethanol was removed by vacuum filter. After a period of time, the mixed solution was poured into a preheated template and defoamed in an oven. The sample was placed in an oven to cure for a period of time. Then, the oven was switched to programmed temperature rise for storage.

[0020] Step (6) Preparation of high-performance green fire-retardant plywood

[0021] Using five-layer eucalyptus veneer, using the high-temperature meal adhesive obtained in step (2), and adding the epoxy resin flame retardant material obtained in step (5), and setting an appropriate amount of adhesive on one side; using the pre-pressing process: setting the unit pressure, cold pressing for a period of time; hot pressing process: setting the hot pressing temperature and unit pressure, hot pressing for a period of time, exhausting the unit pressure, and after the exhaust time is completed, a high-performance green flame-retardant plywood is obtained.

[0022] Preferably, step (1) involves the synthesis of the crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS).

[0023] 2.8–3.1 mmol of 2,5-furandicarboxylic acid (FDCA) and 5.6–7.1 mmol of N-hydroxysuccinimide (NHS) were dissolved in 15–23 mL of dimethyl sulfoxide (DMSO). 5.6–6.9 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) was added to the above solution. The mixture was stirred at 25–35 °C for 48–56 h. After the reaction was completed, the dimethyl sulfoxide (DMSO) was washed away by extraction, the reaction product was purified by column chromatography, and finally dried in a vacuum drying oven at 50–60 °C for later use.

[0024] The advantages of this invention are that it utilizes esterification to synthesize the crosslinking agent furandicarboxylic acid-NHS active ester. 2,5-Furandicarboxylic acid (FDCA), as an important component of FDCA-NHS, exhibits excellent biodegradability, allowing the furandicarboxylic acid-NHS active ester (FDCA-NHS) to decompose naturally under specific conditions, reducing environmental pollution and aligning with current trends in green chemistry and sustainable development. Furthermore, the N-hydroxysuccinimide (NHS) active ester portion endows the furandicarboxylic acid-NHS active ester (FDCA-NHS) with good reactivity and selectivity, providing an excellent foundation for subsequent modification steps.

[0025] Preferably, step (2) involves the preparation of a high-temperature meal adhesive.

[0026] Take flake soybean meal and put it into a grinder to grind for 5-8 minutes, and pass it through a 160-200 mesh sieve to obtain high-temperature soybean meal powder. Take 89.55-91.65g of the crosslinking agent modifier furan dicarboxylic acid-NHS active ester (FDCA-NHS) solution (13.4-15.6wt%) obtained in step (1), add 10.45-11.95g of water to it, stir evenly at room temperature, and adjust the solid content of the solvent to 12.0-13.0wt%. Then add 30.00-35.00g of soybean meal powder, stir at room temperature for 3-5 minutes to form a soybean meal adhesive with a solid content of 30-35wt% and uniformity without particulate matter, and obtain the high-temperature soybean meal adhesive.

[0027] The advantages of this invention are that it uses biomass as a raw material to make adhesives, which has low source cost and conforms to the green concept. Moreover, compared with low-temperature meal, the high-temperature meal is appropriately modified to improve the bonding strength and water resistance of the adhesive, making it superior to the low-temperature meal adhesive. This makes it more suitable for the preparation of soybean meal adhesives, thereby promoting the value-added utilization of high-temperature meal and effectively saving adhesive production costs.

[0028] Preferably, step (3) involves the preparation of the waterborne epoxy resin.

[0029] In a 250-300 mL three-necked flask equipped with a stirrer and a condenser, epoxy resin E-31 and polyethylene glycol (PEG) are added. The mixture is heated to 80-90°C and stirred until melted and homogeneous. Potassium persulfate is dissolved in water and slowly added dropwise to the flask. After mixing for 30-35 minutes, the temperature is raised to obtain a nonionic epoxy emulsifier. The temperature is lowered to 70-75°C, and epoxy resin E-54 is added. The mixture is stirred for 30-35 minutes to ensure homogeneity with the epoxy emulsifier. Then, distilled water is slowly added dropwise while stirring at 1000-1200 rpm. When the viscosity of the system suddenly decreases, the system changes from W / O to O / W. After the water is completely added, stirring is continued for 30-35 minutes to obtain an aqueous epoxy resin with a solid content of 50-52%.

[0030] Preferably, step (4) involves the preparation of the L-Trp-DOPO inorganic phosphorus-containing flame retardant.

[0031] Weigh 1.42~1.86g of L-Trp-BS and 0.75~1g of organophosphorus compound (DOPO) and dissolve them in a three-necked flask containing 45~55mL of tetrahydrofuran. Stir the mixture thoroughly and place it in an oil bath at 110~120℃. React for 12~14h. Wash the precipitated dark yellow product with ethanol and deionized water and dry it overnight in a forced-air oven at 60~65℃ to obtain L-Trp-DOPO inorganic phosphorus flame retardant.

[0032] The advantages of this invention are that it synthesizes an environmentally friendly, low-toxicity, and highly efficient L-Trp-DOPO flame retardant using L-tryptophan, 1,4-benzaldehyde, and organophosphorus compounds (DOPO) as raw materials. Furthermore, by utilizing the Schiff base reaction and then introducing organophosphorus compounds (DOPO) into the Schiff base structure, a novel phosphorus-containing flame retardant, L-Trp-DOPO, is synthesized. This novel flame retardant exhibits superior flame retardancy.

[0033] Preferably, step (5) involves the preparation of the epoxy resin flame retardant material.

[0034] Dissolve the flame retardant L-Trp-DOPO prepared in step (4) in 15-20 mL of anhydrous ethanol, disperse it fully in a water bath at 70-75°C for 15-20 min, add 30-35 mL of epoxy resin obtained in step (3) and stir for 30-45 min, then add 3.4-4.2 mL of diethylenetriamine to the above mixed solution, remove the anhydrous ethanol by vacuum filter for 5-7 min, pour the mixed solution into a preheated template, remove bubbles in an oven at 80-90°C, place the sample in an oven at 80-90°C to cure for 30-35 min, and then switch the oven to a programmed temperature rise to 110-115°C and hold for 3-4 h.

[0035] The advantage of this invention is that it crosslinks a novel flame retardant with epoxy resin. The crosslinked material exhibits excellent flame retardancy while the mechanical properties of the original epoxy resin are not compromised. This indicates that the flame retardant L-Trp-DOPO is uniformly dispersed in the epoxy resin matrix. Furthermore, the non-flammable gases (such as NO and NO2) produced during the combustion of the epoxy resin flame retardant material can act as a diluent for flammable gases, thereby effectively achieving gas-phase flame retardancy.

[0036] Preferably, step (6) involves the preparation of high-performance green fire-retardant plywood.

[0037] Using five layers of eucalyptus veneer, the high-temperature gluten adhesive obtained in step (2) is used, and the epoxy resin flame retardant material obtained in step (5) is added at the same time. The amount of adhesive applied on one side is (260±10) g / m2. The pre-pressing process is used: the unit pressure is (0.7±0.1) MPa, and the cold pressing time is 1~1.5h. The hot pressing process is used: the hot pressing temperature is 125~150℃, the unit pressure is (0.7±0.1) MPa, the hot pressing time is 780~800s, the exhaust unit pressure is (0.2±0.1) MPa, and the exhaust time is 120~130s, to obtain high-performance green flame-retardant plywood.

[0038] The advantages of this invention are that it utilizes biomass raw materials to prepare green and environmentally friendly adhesives, and combines them with novel composite flame-retardant materials to prepare green flame-retardant plywood. High-temperature soybean meal is used to prepare the adhesive, and thermochemical modification improves the bonding strength and water resistance of the high-temperature meal adhesive, making it superior to low-temperature meal adhesives. Furthermore, biomass raw materials have strong regeneration capabilities and high reactivity, conforming to the green concept. The addition of novel flame-retardant materials gives the plywood both excellent flame retardancy and mechanical properties.

[0039] In summary, the present invention has the following beneficial effects:

[0040] 1. The advantages of using this invention are that it utilizes esterification to synthesize the crosslinking agent furandicarboxylic acid-NHS active ester, wherein 2,5-furandicarboxylic acid (FDCA), as an important component of FDCA-NHS, has excellent biodegradability, enabling furandicarboxylic acid-NHS active ester (FDCA-NHS) to decompose naturally under specific conditions, reducing environmental pollution and conforming to the current trend of green chemistry and sustainable development. Furthermore, the N-hydroxysuccinimide (NHS) active ester portion endows furandicarboxylic acid-NHS active ester (FDCA-NHS) with good reactivity and selectivity, providing an excellent foundation for subsequent modification steps.

[0041] 2. The advantages of using this invention are that it uses biomass as raw material to make adhesives, which has low source cost and conforms to the green concept. Moreover, compared with low temperature meal, the high temperature meal is appropriately modified to improve the bonding strength and water resistance of the high temperature meal adhesive, which is superior to the low temperature meal adhesive. This makes it more suitable for the preparation of soybean meal adhesives, thereby promoting the value-added utilization of high temperature meal and effectively saving adhesive production costs.

[0042] 3. The advantages of this invention are that it synthesizes an environmentally friendly, low-toxicity, and highly efficient L-Trp-DOPO flame retardant using L-tryptophan, 1,4-benzaldehyde, and organophosphorus compounds (DOPO) as raw materials. Furthermore, by utilizing the Schiff base reaction and then introducing organophosphorus compounds (DOPO) into the Schiff base structure, a novel phosphorus-containing flame retardant, L-Trp-DOPO, is synthesized. This novel flame retardant exhibits superior flame retardancy.

[0043] 4. The advantage of using this invention is that it crosslinks a novel flame retardant with epoxy resin. The crosslinked material has excellent flame retardancy while the mechanical properties of the original epoxy resin are not destroyed. This indicates that the flame retardant L-Trp-DOPO is uniformly dispersed in the epoxy resin matrix. Furthermore, the non-flammable gases (such as NO and NO2) produced when the epoxy resin flame retardant material burns can act as a diluent for flammable gases, thereby effectively playing a gas-phase flame retardant role.

[0044] 5. The advantages of this invention are that it utilizes biomass raw materials to prepare green and environmentally friendly adhesives, and combines them with novel composite flame-retardant materials to prepare green flame-retardant plywood. High-temperature soybean meal is used to prepare the adhesive, and thermochemical modification improves the bonding strength and water resistance of the high-temperature meal adhesive, making it superior to low-temperature meal adhesives. Furthermore, biomass raw materials have strong regeneration capabilities and high reactivity, conforming to the green concept. The addition of novel flame-retardant materials gives the plywood both excellent flame retardancy and mechanical properties. Attached Figure Description

[0045] Figure 1 A process flow diagram for the preparation of a high-performance, green, fire-retardant plywood. Detailed Implementation

[0046] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the invention. Any modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the invention are within the scope of the invention.

[0047] Unless otherwise specified, the techniques used in the embodiments are conventional methods well known to those skilled in the art. Furthermore, all component raw materials used in the embodiments are known commercially available products. Example 1

[0048] Step (1) Synthesis of crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS)

[0049] 2.8 mmol of 2,5-furandicarboxylic acid (FDCA) and 5.6 mmol of N-hydroxysuccinimide (NHS) were dissolved in 15 mL of dimethyl sulfoxide (DMSO). 5.6 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) was added to the above solution. The mixture was stirred at 25 °C for 48 h. After the reaction was completed, the dimethyl sulfoxide (DMSO) was washed away by extraction, the reaction product was purified by column chromatography, and finally dried in a vacuum oven at 50 °C for later use.

[0050] Step (2) Preparation of high-temperature meal adhesive

[0051] Take flake soybean meal and put it into a grinder to grind for 5 minutes, and pass it through a 100-mesh sieve to obtain high-temperature soybean meal powder. Take 89.55g of the crosslinking agent modifier furan dicarboxylic acid-NHS active ester (FDCA-NHS) solution (13.4wt%) prepared in step (1), add 10.45g of water, stir evenly at room temperature to adjust the solid content of the solvent to 12.0wt%, then add 30.00g of soybean meal powder, stir at room temperature for 3 minutes to form a soybean meal adhesive with a solid content of 30wt% and uniformity without particulate matter, and obtain high-temperature soybean meal adhesive.

[0052] Step (3) Preparation of waterborne epoxy resin

[0053] Epoxy resin E-31 and polyethylene glycol (PEG) were added to a 250 mL three-necked flask equipped with a stirrer and a condenser. The mixture was heated to 80 °C and stirred until it melted and homogeneous. Potassium persulfate was dissolved in water and slowly added dropwise to the flask. After mixing for 30 min, the temperature was raised to obtain a nonionic epoxy emulsifier. The temperature was lowered to 70 °C, and epoxy resin E-54 was added. The mixture was stirred for 30 min to ensure homogeneity with the epoxy emulsifier. Then, distilled water was slowly added dropwise while stirring at 1000 r / min. When the viscosity of the system suddenly decreased, the system changed from W / O to O / W. After adding all the water, the mixture was stirred for another 30 min to obtain an aqueous epoxy resin with a solid content of 50%.

[0054] Step (4) Preparation of L-Trp-DOPO inorganic phosphorus-containing flame retardant

[0055] Weigh 1.42 g L-Trp-BS and 0.75 g organophosphorus compound (DOPO) and dissolve them in a three-necked flask containing 45 mL tetrahydrofuran. Stir the mixture thoroughly and place it in an oil bath at 110 °C. React for 12 h. Wash the precipitated dark yellow product with ethanol and deionized water and dry it overnight in a forced-air oven at 60 °C to obtain L-Trp-DOPO inorganic phosphorus flame retardant.

[0056] Step (5) Preparation of epoxy resin flame retardant material

[0057] Dissolve 1g of the synthetic flame retardant L-Trp-DOPO prepared in step (4) in 15mL of anhydrous ethanol, disperse it fully in a 70℃ water bath for 15 min, add 30mL of the epoxy resin obtained in step (3) and stir for 30 min, then add 3.4mL of diethylenetriamine to the above mixed solution, remove the anhydrous ethanol by vacuum filter for 5 min, pour the mixed solution into a preheated template, remove bubbles in an 80℃ oven, place the sample in an 80℃ oven to cure for 30 min, and then switch the oven to a programmed temperature rise to 110℃ and hold for 3 h;

[0058] Step (6) Preparation of high-performance green fire-retardant plywood

[0059] Five-layer eucalyptus veneer was used, along with the high-temperature gluten adhesive obtained in step (2), and the epoxy resin flame retardant material obtained in step (5) was added. The amount of adhesive applied to one side was 265 g / m². 2 The pre-pressing process is used: unit pressure 0.7MPa, cold pressing time 1h; hot pressing process: hot pressing temperature 125℃, unit pressure 0.7MPa, hot pressing time 780s, exhaust unit pressure 0.2MPa, exhaust time 120s, to obtain high-performance green flame-retardant plywood. Example 2

[0060] Step (1) Synthesis of crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS)

[0061] 2.8 mmol of 2,5-furandicarboxylic acid (FDCA) and 5.6 mmol of N-hydroxysuccinimide (NHS) were dissolved in 15 mL of dimethyl sulfoxide (DMSO). 5.6 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) was added to the above solution. The mixture was stirred at 25 °C for 48 h. After the reaction was completed, the dimethyl sulfoxide (DMSO) was washed away by extraction, the reaction product was purified by column chromatography, and finally dried in a vacuum oven at 50 °C for later use.

[0062] Step (2) Preparation of high-temperature meal adhesive

[0063] Take flake soybean meal and put it into a grinder to grind for 5 minutes, and pass it through a 120-mesh sieve to obtain high-temperature soybean meal powder. Take 89.55g of the crosslinking agent modifier furan dicarboxylic acid-NHS active ester (FDCA-NHS) solution (13.4wt%) prepared in step (1), add 10.45g of water, stir evenly at room temperature to adjust the solid content of the solvent to 12.0wt%, then add 30.00g of soybean meal powder, stir at room temperature for 3 minutes to form a soybean meal adhesive with a solid content of 30wt% and uniformity without particulate matter, and obtain high-temperature soybean meal adhesive.

[0064] Step (3) Preparation of waterborne epoxy resin

[0065] Epoxy resin E-31 and polyethylene glycol (PEG) were added to a 250 mL three-necked flask equipped with a stirrer and a condenser. The mixture was heated to 80 °C and stirred until it melted and homogeneous. Potassium persulfate was dissolved in water and slowly added dropwise to the flask. After mixing for 30 min, the temperature was raised to obtain a nonionic epoxy emulsifier. The temperature was lowered to 70 °C, and epoxy resin E-54 was added. The mixture was stirred for 30 min to ensure homogeneity with the epoxy emulsifier. Then, distilled water was slowly added dropwise while stirring at 1000 r / min. When the viscosity of the system suddenly decreased, the system changed from W / O to O / W. After adding all the water, the mixture was stirred for another 30 min to obtain an aqueous epoxy resin with a solid content of 50%.

[0066] Step (4) Preparation of L-Trp-DOPO inorganic phosphorus-containing flame retardant

[0067] Weigh 1.42 g L-Trp-BS and 0.75 g organophosphorus compound (DOPO) and dissolve them in a three-necked flask containing 45 mL tetrahydrofuran. Stir the mixture thoroughly and place it in an oil bath at 110 °C. React for 12 h. Wash the precipitated dark yellow product with ethanol and deionized water and dry it overnight in a forced-air oven at 60 °C to obtain L-Trp-DOPO inorganic phosphorus flame retardant.

[0068] Step (5) Preparation of epoxy resin flame retardant material

[0069] Dissolve 1.2g of the synthetic flame retardant L-Trp-DOPO prepared in step (4) in 15mL of anhydrous ethanol, disperse it fully in a 70℃ water bath for 15 min, add 30mL of the epoxy resin prepared in step (3) and stir for 30 min, then add 3.4mL of diethylenetriamine to the above mixed solution, remove the anhydrous ethanol by vacuum filter for 5 min, pour the mixed solution into a preheated template, remove bubbles in an 80℃ oven, place the sample in an 80℃ oven to cure for 30 min, and then switch the oven to program temperature rise to 110℃ and hold for 3 h;

[0070] Step (6) Preparation of high-performance green fire-retardant plywood

[0071] Five-layer eucalyptus veneer was used, along with the high-temperature gluten adhesive obtained in step (2), and the epoxy resin flame retardant material obtained in step (5) was added. The amount of adhesive applied to one side was 265 g / m². 2 The pre-pressing process is used: unit pressure 0.7MPa, cold pressing time 1h; hot pressing process: hot pressing temperature 125℃, unit pressure 0.7MPa, hot pressing time 780s, exhaust unit pressure 0.2MPa, exhaust time 120s, to obtain high-performance green flame-retardant plywood. Example 3

[0072] Step (1) Synthesis of crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS)

[0073] 2.8 mmol of 2,5-furandicarboxylic acid (FDCA) and 5.6 mmol of N-hydroxysuccinimide (NHS) were dissolved in 15 mL of dimethyl sulfoxide (DMSO). 5.6 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) was added to the above solution. The mixture was stirred at 25 °C for 48 h. After the reaction was completed, the dimethyl sulfoxide (DMSO) was washed away by extraction, the reaction product was purified by column chromatography, and finally dried in a vacuum oven at 50 °C for later use.

[0074] Step (2) Preparation of high-temperature meal adhesive

[0075] Take flake soybean meal and put it into a grinder to grind for 5 minutes, and pass it through a 160-mesh sieve to obtain high-temperature soybean meal powder. Take 89.55g of the crosslinking agent modifier furan dicarboxylic acid-NHS active ester (FDCA-NHS) solution (13.4wt%) prepared in step (1), add 10.45g of water, stir evenly at room temperature to adjust the solid content of the solvent to 12.0wt%, then add 30.00g of soybean meal powder, stir at room temperature for 3 minutes to form a soybean meal adhesive with a solid content of 30wt% and uniformity without particulate matter, and obtain high-temperature soybean meal adhesive.

[0076] Step (3) Preparation of waterborne epoxy resin

[0077] Epoxy resin E-31 and polyethylene glycol (PEG) were added to a 250 mL three-necked flask equipped with a stirrer and a condenser. The mixture was heated to 80 °C and stirred until it melted and homogeneous. Potassium persulfate was dissolved in water and slowly added dropwise to the flask. After mixing for 30 min, the temperature was raised to obtain a nonionic epoxy emulsifier. The temperature was lowered to 70 °C, and epoxy resin E-54 was added. The mixture was stirred for 30 min to ensure homogeneity with the epoxy emulsifier. Then, distilled water was slowly added dropwise while stirring at 1000 r / min. When the viscosity of the system suddenly decreased, the system changed from W / O to O / W. After adding all the water, the mixture was stirred for another 30 min to obtain an aqueous epoxy resin with a solid content of 50%.

[0078] Step (4) Preparation of L-Trp-DOPO inorganic phosphorus-containing flame retardant

[0079] Weigh 1.42 g L-Trp-BS and 0.75 g organophosphorus compound (DOPO) and dissolve them in a three-necked flask containing 45 mL tetrahydrofuran. Stir the mixture thoroughly and place it in an oil bath at 110 °C. React for 12 h. Wash the precipitated dark yellow product with ethanol and deionized water and dry it overnight in a forced-air oven at 60 °C to obtain L-Trp-DOPO inorganic phosphorus flame retardant.

[0080] Step (5) Preparation of epoxy resin flame retardant material

[0081] Dissolve 2.6g of the synthetic flame retardant L-Trp-DOPO prepared in step (4) in 15mL of anhydrous ethanol, disperse it fully in a 70℃ water bath for 15 min, add 30mL of epoxy resin prepared in step (3) and stir for 30 min, then add 3.4mL of diethylenetriamine to the above mixed solution, remove the anhydrous ethanol by vacuum filter for 5 min, pour the mixed solution into a preheated template, remove bubbles in an 80℃ oven, place the sample in an 80℃ oven to cure for 30 min, and then switch the oven to program temperature rise to 110℃ and hold for 3 h;

[0082] Step (6) Preparation of high-performance green fire-retardant plywood

[0083] Five-layer eucalyptus veneer was used, along with the high-temperature gluten adhesive obtained in step (2), and the epoxy resin flame retardant material obtained in step (5) was added. The amount of adhesive applied to one side was 265 g / m². 2 The pre-pressing process is used: unit pressure 0.7MPa, cold pressing time 1h; hot pressing process: hot pressing temperature 125℃, unit pressure 0.7MPa, hot pressing time 780s, exhaust unit pressure 0.2MPa, exhaust time 120s, to obtain high-performance green flame-retardant plywood. Example 4

[0084] Step (1) Synthesis of crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS)

[0085] 2.8 mmol of 2,5-furandicarboxylic acid (FDCA) and 5.6 mmol of N-hydroxysuccinimide (NHS) were dissolved in 15 mL of dimethyl sulfoxide (DMSO). 5.6 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) was added to the above solution. The mixture was stirred at 25 °C for 48 h. After the reaction was completed, the dimethyl sulfoxide (DMSO) was washed away by extraction, the reaction product was purified by column chromatography, and finally dried in a vacuum oven at 50 °C for later use.

[0086] Step (2) Preparation of high-temperature meal adhesive

[0087] Take flake soybean meal and put it into a grinder to grind for 5 minutes, and pass it through a 200-mesh sieve to obtain high-temperature soybean meal powder. Take 89.55g of the crosslinking agent modifier furan dicarboxylic acid-NHS active ester (FDCA-NHS) solution (13.4wt%) prepared in step (1), add 10.45g of water, stir evenly at room temperature to adjust the solid content of the solvent to 12.0wt%, then add 30.00g of soybean meal powder, stir at room temperature for 3 minutes to form a soybean meal adhesive with a solid content of 30wt% and uniformity without particulate matter, and obtain high-temperature soybean meal adhesive.

[0088] Step (3) Preparation of waterborne epoxy resin

[0089] Epoxy resin E-31 and polyethylene glycol (PEG) were added to a 250 mL three-necked flask equipped with a stirrer and a condenser. The mixture was heated to 80 °C and stirred until it melted and homogeneous. Potassium persulfate was dissolved in water and slowly added dropwise to the flask. After mixing for 30 min, the temperature was raised to obtain a nonionic epoxy emulsifier. The temperature was lowered to 70 °C, and epoxy resin E-54 was added. The mixture was stirred for 30 min to ensure homogeneity with the epoxy emulsifier. Then, distilled water was slowly added dropwise while stirring at 1000 r / min. When the viscosity of the system suddenly decreased, the system changed from W / O to O / W. After adding all the water, the mixture was stirred for another 30 min to obtain an aqueous epoxy resin with a solid content of 50%.

[0090] Step (4) Preparation of L-Trp-DOPO inorganic phosphorus-containing flame retardant

[0091] Weigh 1.42 g L-Trp-BS and 0.75 g organophosphorus compound (DOPO) and dissolve them in a three-necked flask containing 45 mL tetrahydrofuran. Stir the mixture thoroughly and place it in an oil bath at 110 °C. React for 12 h. Wash the precipitated dark yellow product with ethanol and deionized water and dry it overnight in a forced-air oven at 60 °C to obtain L-Trp-DOPO inorganic phosphorus flame retardant.

[0092] Step (5) Preparation of epoxy resin flame retardant material

[0093] Dissolve 1.7g of the synthetic flame retardant L-Trp-DOPO prepared in step (4) in 15mL of anhydrous ethanol, disperse it fully in a 70℃ water bath for 15 min, add 30mL of epoxy resin prepared in step (3) and stir for 30 min, then add 3.4mL of diethylenetriamine to the above mixed solution, remove the anhydrous ethanol by vacuum filter for 5 min, pour the mixed solution into a preheated template, remove bubbles in an 80℃ oven, place the sample in an 80℃ oven to cure for 30 min, and then switch the oven to program temperature rise to 110℃ and hold for 3 h;

[0094] Step (6) Preparation of high-performance green fire-retardant plywood

[0095] Five-layer eucalyptus veneer was used, along with the high-temperature gluten adhesive obtained in step (2), and the epoxy resin flame retardant material obtained in step (5) was added. The adhesive application rate on one side was 265 g / m². 2 The pre-pressing process is used: unit pressure 0.7MPa, cold pressing time 1h; hot pressing process: hot pressing temperature 125℃, unit pressure 0.7MPa, hot pressing time 780s, exhaust unit pressure 0.2MPa, exhaust time 120s, to obtain high-performance green flame-retardant plywood.

[0096] Comparative Example 1

[0097] Step (1) Preparation of high-temperature meal adhesive

[0098] Take flake soybean meal and grind it in a grinder for 5 minutes, then pass it through a 220-mesh sieve to obtain high-temperature soybean meal powder. Take 89.55g of crosslinking agent modifier furan dicarboxylic acid-NHS active ester (FDCA-NHS) solution (13.4wt%), add 10.45g of water, stir evenly at room temperature to adjust the solid content of the solvent to 12.0wt%, then add 30.00g of soybean meal powder, stir at room temperature for 3 minutes to form a soybean meal adhesive with a solid content of 30wt% and uniformity without particulate matter, thus obtaining the high-temperature soybean meal adhesive.

[0099] Step (2) Preparation of waterborne epoxy resin

[0100] Epoxy resin E-31 and polyethylene glycol (PEG) were added to a 250 mL three-necked flask equipped with a stirrer and a condenser. The mixture was heated to 80 °C and stirred until it melted and homogeneous. Potassium persulfate was dissolved in water and slowly added dropwise to the flask. After mixing for 30 min, the temperature was raised to obtain a nonionic epoxy emulsifier. The temperature was lowered to 70 °C, and epoxy resin E-54 was added. The mixture was stirred for 30 min to ensure homogeneity with the epoxy emulsifier. Then, distilled water was slowly added dropwise while stirring at 1000 r / min. When the viscosity of the system suddenly decreased, the system changed from W / O to O / W. After adding all the water, the mixture was stirred for another 30 min to obtain an aqueous epoxy resin with a solid content of 50%.

[0101] Step (3) Preparation of L-Trp-DOPO inorganic phosphorus-containing flame retardant

[0102] Weigh 1.42 g L-Trp-BS and 0.75 g organophosphorus compound (DOPO) and dissolve them in a three-necked flask containing 45 mL tetrahydrofuran. Stir the mixture thoroughly and place it in an oil bath at 110 °C. React for 12 h. Wash the precipitated dark yellow product with ethanol and deionized water and dry it overnight in a forced-air oven at 60 °C to obtain L-Trp-DOPO inorganic phosphorus flame retardant.

[0103] Step (4) Preparation of epoxy resin flame retardant material

[0104] Dissolve 0.5g of the synthetic flame retardant L-Trp-DOPO prepared in step (3) in 15mL of anhydrous ethanol, disperse it fully in a 70℃ water bath for 15 min, add 30mL of epoxy resin prepared in step (2) and stir for 30 min, then add 3.4mL of diethylenetriamine to the above mixed solution, remove the anhydrous ethanol by vacuum filter for 5 min, pour the mixed solution into a preheated template, remove bubbles in an 80℃ oven, place the sample in an 80℃ oven to cure for 30 min, and then switch the oven to program temperature rise to 110℃ and hold for 3 h;

[0105] Step (5) Preparation of high-performance green fire-retardant plywood

[0106] Five-layer eucalyptus veneer was used, along with the high-temperature gluten adhesive obtained in step (1), and the epoxy resin flame retardant material obtained in step (4) was added. The single-sided coating amount was 265g / m². 2 The pre-pressing process is used: unit pressure 0.7MPa, cold pressing time 1h; hot pressing process: hot pressing temperature 125℃, unit pressure 0.7MPa, hot pressing time 780s, exhaust unit pressure 0.2MPa, exhaust time 120s, to obtain high-performance green flame-retardant plywood.

[0107] Comparative Example 2

[0108] Step (1) Synthesis of crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS)

[0109] 2.8 mmol of 2,5-furandicarboxylic acid (FDCA) and 5.6 mmol of N-hydroxysuccinimide (NHS) were dissolved in 15 mL of dimethyl sulfoxide (DMSO). 5.6 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) was added to the above solution. The mixture was stirred at 25 °C for 48 h. After the reaction was completed, the dimethyl sulfoxide (DMSO) was washed away by extraction, the reaction product was purified by column chromatography, and finally dried in a vacuum oven at 50 °C for later use.

[0110] Step (2) Preparation of high-temperature meal adhesive

[0111] Take flake soybean meal and put it into a grinder to grind for 5 minutes, and pass it through a 240-mesh sieve to obtain high-temperature soybean meal powder. Take 89.55g of the crosslinking agent modifier furan dicarboxylic acid-NHS active ester (FDCA-NHS) solution (13.4wt%) prepared in step (1), add 10.45g of water, stir evenly at room temperature to adjust the solid content of the solvent to 12.0wt%, then add 30.00g of soybean meal powder, stir at room temperature for 3 minutes to form a soybean meal adhesive with a solid content of 30wt% and uniformity without particulate matter, and obtain high-temperature soybean meal adhesive.

[0112] Step (3) Preparation of L-Trp-DOPO inorganic phosphorus-containing flame retardant

[0113] Weigh 1.42 g L-Trp-BS and 0.75 g organophosphorus compound (DOPO) and dissolve them in a three-necked flask containing 45 mL tetrahydrofuran. Stir the mixture thoroughly and place it in an oil bath at 110 °C. React for 12 h. Wash the precipitated dark yellow product with ethanol and deionized water and dry it overnight in a forced-air oven at 60 °C to obtain L-Trp-DOPO inorganic phosphorus flame retardant.

[0114] Step (4) Preparation of epoxy resin flame retardant material

[0115] Dissolve 0.8g of the synthetic flame retardant L-Trp-DOPO prepared in step (3) in 15mL of anhydrous ethanol, disperse it fully in a 70℃ water bath for 15 min, add 30mL of epoxy resin and stir for 30 min, then add 3.4mL of diethylenetriamine to the above mixed solution, remove the anhydrous ethanol through a vacuum filter for 5 min, pour the mixed solution into a preheated template, remove bubbles in an 80℃ oven, place the sample in an 80℃ oven to cure for 30 min, and then switch the oven to a programmed temperature rise to 110℃ and hold for 3 h;

[0116] Step (5) Preparation of high-performance green fire-retardant plywood

[0117] Five-layer eucalyptus veneer was used, along with the high-temperature gluten adhesive obtained in step (2), and the epoxy resin flame retardant material obtained in step (4) was added. The adhesive application rate on one side was 265 g / m². 2 The pre-pressing process is used: unit pressure 0.7MPa, cold pressing time 1h; hot pressing process: hot pressing temperature 125℃, unit pressure 0.7MPa, hot pressing time 780s, exhaust unit pressure 0.2MPa, exhaust time 120s, to obtain high-performance green flame-retardant plywood.

[0118] Comparison of detection experiments:

[0119] The green flame-retardant plywood obtained in Examples 1 to 4 and comparative products 1 and 2 were tested. The specific testing methods are as follows:

[0120] Adhesion performance test

[0121] According to the Chinese national standard GB / T 9846—2015, the dry strength and wet strength were determined using a SANS universal testing machine. Thirty specimens with a bonding area of ​​25mm×25mm were cut from each plywood. Ten specimens were tested for each strength (five loose specimens and five tight specimens). The displacement control mode was used, and the speed was 5.0mm / min.

[0122] Cone calorimetry (CCT) analysis

[0123] The flame-retardant properties of L-Trp-DOPO compounds on epoxy resin matrix materials were investigated using a cone calorimeter. The cone calorimeter operates on the principle of oxygen consumption, meaning that the heat released for each unit of oxygen consumed during combustion of a flame-retardant material is essentially the same. In the experiment, by measuring the mass of oxygen consumed during combustion, parameters such as the material's heat release rate can be calculated.

[0124] Table 1. Results of Adhesion Performance Tests

[0125]

[0126] As shown in Table 1, Example 3 exhibits the best bonding performance, while Comparative Example 2 is relatively poor. The bonding performance first increases and then decreases as the soybean meal particle size decreases. The adhesive prepared from soybean meal with a particle size of 160 mesh has the highest bonding performance, indicating that the optimal particle size is 160 mesh.

[0127] Table 2. Results of Cone Calorimetry Test

[0128]

[0129] As shown in Table 2, Example 3 had the highest Limiting Oxygen Index (LOI), while Comparative Example 1 had a lower LOI. A higher LOI indicates better flame retardant performance of the material. The LOI increases with the increase of the L-Trp-DOPO content, reaching saturation at a content of 7% (2.6g). Further increasing the content has no significant effect. Therefore, the flame retardant material exhibits the best flame retardant performance at a L-Trp-DOPO content of 2.6g, providing excellent performance in the preparation of flame-retardant plywood and demonstrating good potential.

Claims

1. A preparation process for a high-performance, green, flame-retardant plywood, characterized in that, include: Synthesis of crosslinking agent furanyl dicarboxylic acid-NHS active ester (FDCA-NHS), preparation of high-temperature meal adhesive, preparation of waterborne epoxy resin, preparation of L-Trp-DOPO inorganic phosphorus-containing flame retardant, preparation of epoxy resin flame retardant materials, and preparation of high-performance green flame-retardant plywood; among which: Step (1) Synthesis of crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS) 2,5-furandicarboxylic acid (FDCA) and N-hydroxysuccinimide (NHS) were dissolved in dimethyl sulfoxide (DMSO), and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) was added. The mixture was stirred at a certain temperature. After the reaction was completed, the dimethyl sulfoxide (DMSO) was washed away by extraction, the reaction product was purified by column chromatography, and finally dried in a vacuum drying oven at a certain temperature for later use. Step (2) Preparation of high-temperature meal adhesive Take the flakes of soybean meal and put them into a grinder to grind them and pass them through a sieve to obtain soybean meal powder. Add water to the crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS) solution obtained in step (1), stir evenly at room temperature, adjust the solid content of the solvent, and then add soybean meal powder. Stir at room temperature to form a uniform soybean meal adhesive without particulate matter, and obtain a high temperature soybean meal adhesive. Step (3) Preparation of waterborne epoxy resin Epoxy resin E-31 and polyethylene glycol (PEG) were added to a three-necked flask equipped with a stirrer and a condenser. The mixture was heated until it melted and stirred until homogeneous. Potassium persulfate was dissolved in water and slowly added dropwise to the flask. After mixing until homogeneous, the temperature was raised to obtain a nonionic epoxy emulsifier. The temperature was lowered, and epoxy resin E-54 was added. The mixture was stirred until homogeneous with the epoxy emulsifier. Then, distilled water was slowly added dropwise at a certain stirring speed. When the viscosity of the system suddenly decreased, the system changed from W / O to O / W. After the water was added, the mixture was stirred for a period of time to obtain an aqueous epoxy resin. Step (4) Preparation of L-Trp-DOPO inorganic phosphorus-containing flame retardant Weigh a certain amount of L-Trp-BS and organophosphorus compound (DOPO) and dissolve them in a three-necked flask containing tetrahydrofuran. Stir the mixture thoroughly and place it in an oil bath. React for a period of time and wash the precipitated dark yellow product with ethanol and deionized water. Dry it overnight in a forced-air oven at a certain temperature to obtain L-Trp-DOPO inorganic phosphorus flame retardant. Step (5) Preparation of epoxy resin flame retardant material The flame retardant L-Trp-DOPO prepared in step (4) was dissolved in anhydrous ethanol and dispersed in a water bath for a period of time. The epoxy resin obtained in step (3) was added and stirred. Then, diethylenetriamine was added to the above mixed solution. Anhydrous ethanol was removed by vacuum filter. After a period of time, the mixed solution was poured into a preheated template and defoamed in an oven. The sample was placed in an oven to cure for a period of time. Then, the oven was switched to programmed temperature rise for storage. Step (6) Preparation of high-performance green fire-retardant plywood Five-layer eucalyptus veneer was used, along with the high-temperature meal adhesive obtained in step (2) and the epoxy resin flame retardant material obtained in step (5). An appropriate amount of adhesive was applied to one side. A pre-pressing process was used: the unit pressure was set and the material was cold-pressed for a period of time. Hot pressing process: Set the hot pressing temperature and unit pressure, hot press for a period of time, exhaust the unit pressure (0.2±0.1) MPa, and after the exhaust time is completed, high-performance green fire-retardant plywood is obtained.

2. The preparation process of a high-performance green flame-retardant plywood according to claim 1, characterized in that: Step (1) Synthesis of crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS) 2.8–3.1 mmol of 2,5-furandicarboxylic acid (FDCA) and 5.6–7.1 mmol of N-hydroxysuccinimide (NHS) were dissolved in 15–23 mL of dimethyl sulfoxide (DMSO). 5.6–6.9 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) was added to the above solution. The mixture was stirred at 25–35 °C for 48–56 h. After the reaction was completed, the dimethyl sulfoxide (DMSO) was washed away by extraction, the reaction product was purified by column chromatography, and finally dried in a vacuum drying oven at 50–60 °C for later use.

3. The preparation process of a high-performance green flame-retardant plywood according to claim 2, characterized in that: Step (2) Preparation of high-temperature meal adhesive Take flake soybean meal and put it into a grinder to grind for 5-8 minutes, and pass it through a 160-200 mesh sieve to obtain soybean meal powder. Take 89.55-91.65g of the crosslinking agent furan dicarboxylic acid-NHS active ester (FDCA-NHS) solution (13.4-15.6wt%) obtained in step (1), add 10.45-11.95g of water to it, stir evenly at room temperature, and adjust the solid content of the solvent to 12.0-13.0wt%. Then add 30.00-35.00g of soybean meal powder, stir at room temperature for 3-5 minutes to form a soybean meal adhesive with a solid content of 30-35wt% and uniformity without particulate matter, and obtain a high-temperature soybean meal adhesive.

4. The preparation process of a high-performance green fire-retardant plywood according to claim 3, characterized in that: Step (3) Preparation of waterborne epoxy resin In a 250-300 mL three-necked flask equipped with a stirrer and a condenser, epoxy resin E-31 and polyethylene glycol (PEG) are added. The mixture is heated to 80-90°C and stirred until melted and homogeneous. Potassium persulfate is dissolved in water and slowly added dropwise to the flask. After mixing for 30-35 minutes, the temperature is raised to obtain a nonionic epoxy emulsifier. The temperature is lowered to 70-75°C, and epoxy resin E-54 is added. The mixture is stirred for 30-35 minutes to ensure homogeneity with the epoxy emulsifier. Then, distilled water is slowly added dropwise while stirring at 1000-1200 rpm. When the viscosity of the system suddenly decreases, the system changes from W / O to O / W. After the water is completely added, stirring is continued for 30-35 minutes to obtain an aqueous epoxy resin with a solid content of 50-52%.

5. The preparation process of a high-performance green fire-retardant plywood according to claim 4, characterized in that: Step (4) Preparation of L-Trp-DOPO inorganic phosphorus-containing flame retardant Weigh 1.42~1.86g of L-Trp-BS and 0.75~1g of organophosphorus compound (DOPO) and dissolve them in a three-necked flask containing 45~55mL of tetrahydrofuran. Stir the mixture thoroughly and place it in an oil bath at 110~120℃. React for 12~14h. Wash the precipitated dark yellow product with ethanol and deionized water and dry it overnight in a forced-air oven at 60~65℃ to obtain L-Trp-DOPO inorganic phosphorus flame retardant.

6. The preparation process of a high-performance green flame-retardant plywood according to claim 5, characterized in that: Step (5) Preparation of epoxy resin flame retardant material Dissolve the flame retardant L-Trp-DOPO prepared in step (4) in 15-20 mL of anhydrous ethanol, disperse it fully in a water bath at 70-75°C for 15-20 min, add 30-35 mL of epoxy resin obtained in step (3) and stir for 30-45 min, then add 3.4-4.2 mL of diethylenetriamine to the above mixed solution, remove the anhydrous ethanol by vacuum filter for 5-7 min, pour the mixed solution into a preheated template, remove bubbles in an oven at 80-90°C, place the sample in an oven at 80-90°C to cure for 30-35 min, and then switch the oven to a programmed temperature rise to 110-115°C and hold for 3-4 h.

7. The preparation process of a high-performance green flame-retardant plywood according to claim 6, characterized in that: Step (6) Preparation of high-performance green fire-retardant plywood Using five-layer eucalyptus veneer, the high-temperature gluten adhesive obtained in step (2) is used, along with the epoxy resin flame retardant material obtained in step (5). The amount of adhesive applied to one side is (260±10) g / m². 2 Pre-pressing process: unit pressure (0.7±0.1) MPa, cold pressing time 1~1.5h; hot pressing process: hot pressing temperature 125~150℃, unit pressure (0.7±0.1) MPa, hot pressing time 780~800s, exhaust time 120~130s, to obtain high-performance green flame-retardant plywood.

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