Flame-retardant laminated solid wood composite floor and preparation method thereof

Abstract

The present invention relates to the technical field of solid wood flooring, and in particular to a flame-retardant laminated solid wood composite flooring and a preparation method thereof. The method comprises the following steps: firstly reacting dopamine hydrochloride with acryloyl chloride to generate a dopamine monomer; then utilizing the double bond of the dopamine monomer to undergo a click reaction with a phosphate monomer containing a mercapto group, thereby introducing a catechol group into the side chain of the phosphate monomer to obtain a flame-retardant monomer containing a double bond; and then mixing pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol triacrylate, perfluorodecyl mercaptan, and the flame-retardant monomer containing a double bond to obtain a light-curable coating. The coating is applied to the surface of a wood veneer and then light-cured, thereby effectively improving the flame-retardant properties of the wood veneer. The coating also has excellent adhesion to the wood veneer. The wood veneers are laminated in multiple layers, assembled after being coated with glue, and hot-pressed to obtain a wood composite flooring, thereby improving overall performance.

Description

Technical Field

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

[0002] Solid wood composite flooring is made by laminating multiple layers of wood planks with glue. In actual production and processing, the performance requirements for single-layer wood planks are more stringent, requiring them to have excellent flame retardancy. There are many flame-retardant modification methods for wood planks, and in recent years, a variety of flame-retardant wood planks have emerged on the market, specifically categorized as surface treatment, veneer treatment, and deep treatment. Surface treatment involves directly coating, spraying, or depositing flame-retardant polymers or monomers on the wood surface, and then cross-linking and curing them through physical and chemical methods to form a protective layer on the wood surface to isolate it from heat sources. Common surface treatment methods include surface coating.

[0003] However, the flame retardant properties of existing wood boards on the market cannot meet actual needs, and the adhesion between the coating and the wood board after surface treatment is poor, which brings inconvenience to practical applications; based on this situation, the present application discloses a flame retardant laminated solid wood composite floor and a preparation method thereof to solve this technical problem. Summary of the Invention

[0004] The object of the present invention is to provide a flame retardant laminated solid wood composite floor and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A method for preparing a flame-retardant laminated solid wood composite floor comprises the following steps:

[0007] Step S1: Sodium carbonate, sodium borate decahydrate and deionized water are mixed, nitrogen is introduced to remove oxygen, dopamine hydrochloride is added under nitrogen, and the mixture is stirred evenly. Acryloyl chloride is then added, and sodium carbonate is added to maintain the pH at 8-9. The mixture is reacted at 25-30° C. for 12-14 hours. After the reaction is completed, the pH is adjusted to 1 with hydrochloric acid, and the mixture is extracted with ethyl acetate, dried over anhydrous copper sulfate, and recrystallized to obtain a dopamine monomer.

[0008] Step S2: nitrogen is introduced into anhydrous methanol to remove oxygen, dopamine monomer is added under nitrogen atmosphere, stirred and dissolved, and then a phosphate monomer containing a mercapto group and a photoinitiator are added. Under ultraviolet light (λ = 365 nm), the mixture is stirred and reacted for 0.5 to 1 hour. After the reaction is completed, the solvent is removed to obtain a flame retardant monomer containing a double bond;

[0009] Step S3: Pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol triacrylate, perfluorodecanethiol and a flame retardant monomer containing a double bond are mixed, a photoinitiator is added, and the mixture is stirred evenly to obtain a coating material;

[0010] Step S4: polishing the surface of the wood veneer, ultrasonically cleaning with deionized water, vacuum drying at 60°C for 12 hours, and then evenly applying the coating material to the surface of the wood veneer. Curing under ultraviolet light (λ=365nm) for 3-5 minutes to obtain a flame-retardant wood veneer; applying glue on the surface of several flame-retardant wood veneers, stacking and assembling them, and hot pressing to form a composite floor.

[0011] In a more optimized solution, in step S3, the molar ratio of pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol triacrylate, perfluorodecanethiol, and flame retardant monomer containing a double bond is 3:4:(1-1.2):(1-1.2); the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator used is 2-2.5wt% of the total mass of the coating.

[0012] In a more optimized solution, in step S1, the molar ratio of dopamine hydrochloride to acryloyl chloride is 1:1; the molar ratio of dopamine hydrochloride to sodium borate decahydrate is 1:1.

[0013] In a more optimized solution, in step S2, the preparation steps of the thiol-containing phosphate monomer are as follows:

[0014] (1) Trimethylolpropane, mercaptopropionic acid, a catalyst and toluene are mixed and reacted under nitrogen for 3-4 hours at a temperature of 70-80°C. After the reaction, the mixture is washed with water and the organic solvent is removed by distillation to obtain a mercapto monomer;

[0015] (2) mixing phenyl dichlorophosphate and tetrahydrofuran, and stirring uniformly to obtain a phenyl dichlorophosphate solution;

[0016] Mix hydroxyethyl acrylate, triethylamine and tetrahydrofuran, stir evenly, add phenyl dichlorophosphate solution under ice-water bath, react at 0°C for 8-10 hours, then add thiol monomer, react at 50-60°C for 4-6 hours, collect the product, and purify it to obtain a phosphate monomer containing a thiol group.

[0017] In a more optimized solution, the molar ratio of trimethylolpropane to mercaptopropionic acid is 1:(2.1-2.3); the catalyst is p-toluenesulfonic acid, and the amount of the catalyst used is 2.5-3wt% of the total mass of trimethylolpropane and mercaptopropionic acid.

[0018] In a more optimized solution, the concentration of the phenyl dichlorophosphate solution is 2-3 mol / L; the molar ratio of the hydroxyethyl acrylate, phenyl dichlorophosphate, and mercapto monomer is 1:(1-1.2):1; and the molar ratio of the hydroxyethyl acrylate and triethylamine is 1:2.

[0019] In a more optimized solution, in step S2, the molar ratio of the thiol-containing phosphate monomer and the dopamine monomer is 1:2; the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator used is 1.5-2.5 wt% of the total mass of the thiol-containing phosphate monomer and the dopamine monomer.

[0020] In the optimized solution, in step S4, the coating thickness is 0.2-0.4 mm; the amount of glue applied on one side is 120 g / m 2 .

[0021] In a more optimized solution, the wooden veneer is any one of poplar, eucalyptus and pine.

[0022] A more optimized solution is a solid wood composite floor prepared according to any one of the above methods for preparing a flame-retardant laminated solid wood composite floor.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The invention discloses a method for preparing a flame-retardant laminated solid wood composite floor. The method comprises the following steps: first, dopamine hydrochloride and acryloyl chloride are reacted to generate dopamine acrylamide (dopamine monomer); then, the double bond of the dopamine acrylamide is subjected to a click reaction with a phosphate monomer containing a mercapto group, thereby introducing a catechol group into the side chain of the phosphate monomer to obtain a flame-retardant monomer containing a double bond; and then, a light-curing coating is obtained by mixing pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol triacrylate, perfluorodecyl mercaptan, and the flame-retardant monomer containing a double bond. The coating is coated on the surface of a wood veneer and then light-cured, thereby effectively improving the flame-retardant properties of the wood veneer and providing excellent adhesion between the coating and the wood veneer. The wood veneer can be laminated in multiple layers, assembled after gluing, and hot-pressed to obtain a wood composite floor, thereby improving overall performance.

[0025] In this scheme, the introduction of dopamine acrylamide can introduce catechol groups into the system. The presence of catechol groups can effectively improve the adhesion between the wood veneer and the coating, allowing the coating to tightly bond to the wood veneer surface. Furthermore, the scheme utilizes trimethylolpropane and mercaptopropionic acid for esterification, with the molar ratio of trimethylolpropane to mercaptopropionic acid controlled to be 1:(2.1-2.3) to generate a mercapto monomer containing two mercapto groups and one hydroxyl group. The mercapto monomer is then grafted onto one end of phenyl dichlorophosphate. The other end of the phenyl dichlorophosphate reacts with hydroxyethyl acrylate to introduce a double bond, resulting in a phosphate monomer containing a mercapto group. The mercapto groups provided by the mercapto monomer are then used to bridge dopamine monomers, generating a flame-retardant monomer containing a double bond, thereby improving the surface flame retardancy of the wood veneer. The present invention also introduces perfluorodecanethiol, utilizing the mercapto groups provided by the perfluorodecanethiol to participate in crosslinking in the photocuring system and introducing fluorine to improve the water resistance and waterproofing of the wood veneer.

[0026] The present invention discloses a method for preparing a flame-retardant laminated solid wood composite floor, wherein a wood veneer with excellent flame-retardant performance is prepared, and the wood veneer is coated with glue and then laminated and hot-pressed to produce a composite floor with excellent comprehensive performance. The composite floor can be widely used in fields such as home decoration and has high practicality. DETAILED DESCRIPTION

[0027] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all 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.

[0028] In this example, dopamine hydrochloride and 1H,1H,2H,2H-perfluorodecanethiol were provided by Aladdin. The wood veneer was poplar veneer, 1.9 mm thick, and had an initial moisture content of 8%. Urea-formaldehyde resin glue or other adhesives that achieve adhesion were used for gluing the laminate flooring, all of which are commercially available.

[0029] Example 1: A method for preparing a flame-retardant laminated solid wood composite floor, comprising the following steps:

[0030] Step S1: 47.5 mmol of sodium carbonate, 16.2 mmol of sodium borate decahydrate and 300 mL of deionized water were mixed, nitrogen was introduced to deoxygenate, 16.2 mmol of dopamine hydrochloride was added under nitrogen, and the mixture was stirred evenly. Then, 16.2 mmol of acryloyl chloride was added, and sodium carbonate was added to maintain the pH at 9. The mixture was reacted at 25°C for 14 h. After the reaction, the pH was adjusted to 1 with hydrochloric acid, the mixture was extracted with ethyl acetate, dried over anhydrous copper sulfate, and recrystallized to obtain dopamine monomer.

[0031] Step S2: Nitrogen is introduced into anhydrous methanol to remove oxygen, 0.2 mol of dopamine monomer is added under nitrogen environment, and the mixture is stirred and dissolved. Then, 0.1 mol of phosphate monomer containing a mercapto group and a photoinitiator are added. Under ultraviolet light (λ = 365 nm), the mixture is stirred and reacted for 0.5 h. After the reaction, the solvent is removed to obtain a flame retardant monomer containing a double bond; the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator used is 2 wt% of the total mass of the phosphate monomer containing a mercapto group and the dopamine monomer.

[0032] The preparation steps of the phosphate monomer containing mercapto group are as follows:

[0033] (1) 0.1 mol of trimethylolpropane, 0.21 mol of mercaptopropionic acid, a catalyst and toluene were mixed and reacted for 3 h under nitrogen atmosphere at a temperature of 80 °C. After the reaction, the mixture was washed with water and the organic solvent was removed by distillation to obtain a mercapto monomer; the catalyst was p-toluenesulfonic acid, and the amount of the catalyst was 2.5 wt% of the total mass of trimethylolpropane and mercaptopropionic acid.

[0034] (2) Phenyl dichlorophosphate and tetrahydrofuran are mixed and stirred uniformly to obtain a phenyl dichlorophosphate solution; the concentration of the phenyl dichlorophosphate solution is 2 mol / L.

[0035] Mix 0.1 mol of hydroxyethyl acrylate, 0.2 mol of triethylamine and 100 mL of tetrahydrofuran, stir evenly, add 0.12 mol of phenyl dichlorophosphate solution under ice-water bath, react at 0°C for 8 h, then add 0.1 mol of thiol monomer, react at 50°C for 6 h, collect the product, and purify it to obtain a phosphate monomer containing a thiol group.

[0036] Step S3: 0.3 mol of pentaerythritol tetrakis(3-mercaptopropionate), 0.4 mol of pentaerythritol triacrylate, 0.1 mol of perfluorodecanethiol and 0.1 mol of a flame retardant monomer containing a double bond are mixed, a photoinitiator is added, and the mixture is stirred evenly to obtain a coating material; the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator used is 2.5 wt% of the total mass of the coating material.

[0037] Step S4: The surface of the wood veneer is polished and smoothed, ultrasonically cleaned with deionized water, and vacuum dried at 60° C. for 12 hours. The coating material is then evenly applied to the surface of the wood veneer and cured under ultraviolet light (λ=365 nm) for 5 minutes to obtain a flame-retardant wood veneer; the coating material coating thickness is 0.3 mm.

[0038] Glue is applied to the surface of several flame retardant wood veneers, stacked and assembled, and hot pressed to form a composite floor. The amount of glue applied on one side is 120g / m 2 .

[0039] Example 2: A method for preparing a flame-retardant laminated solid wood composite floor, comprising the following steps:

[0040] Step S1: 47.5 mmol of sodium carbonate, 16.2 mmol of sodium borate decahydrate and 300 mL of deionized water were mixed, nitrogen was introduced to deoxygenate, 16.2 mmol of dopamine hydrochloride was added under nitrogen, and the mixture was stirred evenly. Then, 16.2 mmol of acryloyl chloride was added, and sodium carbonate was added to maintain the pH at 9. The mixture was reacted at 30° C. for 12 h. After the reaction, the pH was adjusted to 1 with hydrochloric acid, the mixture was extracted with ethyl acetate, dried over anhydrous copper sulfate, and recrystallized to obtain dopamine monomer.

[0041] Step S2: Nitrogen is introduced into anhydrous methanol to remove oxygen, 0.2 mol of dopamine monomer is added under nitrogen environment, and the mixture is stirred and dissolved. Then, 0.1 mol of phosphate monomer containing a mercapto group and a photoinitiator are added. Under ultraviolet light (λ = 365 nm), the mixture is stirred and reacted for 0.5 h. After the reaction, the solvent is removed to obtain a flame retardant monomer containing a double bond; the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator used is 2 wt% of the total mass of the phosphate monomer containing a mercapto group and the dopamine monomer.

[0042] The preparation steps of the phosphate monomer containing mercapto group are as follows:

[0043] (1) 0.1 mol of trimethylolpropane, 0.21 mol of mercaptopropionic acid, a catalyst and toluene were mixed and reacted for 3.5 h under nitrogen atmosphere at a temperature of 75 °C. After the reaction, the mixture was washed with water and the organic solvent was removed by distillation to obtain a mercapto monomer; the catalyst was p-toluenesulfonic acid, and the amount of the catalyst was 2.5 wt% of the total mass of trimethylolpropane and mercaptopropionic acid.

[0044] (2) Phenyl dichlorophosphate and tetrahydrofuran are mixed and stirred uniformly to obtain a phenyl dichlorophosphate solution; the concentration of the phenyl dichlorophosphate solution is 2 mol / L.

[0045] Mix 0.1 mol of hydroxyethyl acrylate, 0.2 mol of triethylamine and 100 mL of tetrahydrofuran, stir evenly, add 0.12 mol of phenyl dichlorophosphate solution under ice-water bath, react at 0°C for 9 h, then add 0.1 mol of thiol monomer, react at 55°C for 5 h, collect the product, and purify it to obtain a phosphate monomer containing a thiol group.

[0046] Step S3: 0.3 mol of pentaerythritol tetrakis(3-mercaptopropionate), 0.4 mol of pentaerythritol triacrylate, 0.11 mol of perfluorodecanethiol and 0.11 mol of a flame retardant monomer containing a double bond are mixed, a photoinitiator is added, and the mixture is stirred evenly to obtain a coating material; the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator used is 2.5 wt% of the total mass of the coating material.

[0047] Step S4: The surface of the wood veneer is polished and smoothed, ultrasonically cleaned with deionized water, and vacuum dried at 60° C. for 12 hours. The coating material is then evenly applied to the surface of the wood veneer and cured under ultraviolet light (λ=365 nm) for 5 minutes to obtain a flame-retardant wood veneer; the coating material coating thickness is 0.3 mm.

[0048] Glue is applied to the surface of several flame retardant wood veneers, stacked and assembled, and hot pressed to form a composite floor. The amount of glue applied on one side is 120g / m 2 .

[0049] Example 3: A method for preparing a flame-retardant laminated solid wood composite floor, comprising the following steps:

[0050] Step S1: 47.5 mmol of sodium carbonate, 16.2 mmol of sodium borate decahydrate and 300 mL of deionized water were mixed, nitrogen was introduced to deoxygenate, 16.2 mmol of dopamine hydrochloride was added under nitrogen, and the mixture was stirred evenly. Then, 16.2 mmol of acryloyl chloride was added, and sodium carbonate was added to maintain the pH at 9. The mixture was reacted at 30° C. for 12 h. After the reaction, the pH was adjusted to 1 with hydrochloric acid, the mixture was extracted with ethyl acetate, dried over anhydrous copper sulfate, and recrystallized to obtain dopamine monomer.

[0051] Step S2: Nitrogen is introduced into anhydrous methanol to remove oxygen, 0.2 mol of dopamine monomer is added under nitrogen environment, and the mixture is stirred and dissolved. Then, 0.1 mol of phosphate monomer containing a mercapto group and a photoinitiator are added. Under ultraviolet light (λ = 365 nm), the mixture is stirred and reacted for 0.5 h. After the reaction, the solvent is removed to obtain a flame retardant monomer containing a double bond; the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator used is 2 wt% of the total mass of the phosphate monomer containing a mercapto group and the dopamine monomer.

[0052] The preparation steps of the phosphate monomer containing mercapto group are as follows:

[0053] (1) 0.1 mol of trimethylolpropane, 0.21 mol of mercaptopropionic acid, a catalyst and toluene were mixed and reacted for 4 h under nitrogen at a temperature of 70°C. After the reaction, the mixture was washed with water and the organic solvent was removed by distillation to obtain a mercapto monomer; the catalyst was p-toluenesulfonic acid, and the amount of the catalyst was 2.5 wt% of the total mass of trimethylolpropane and mercaptopropionic acid.

[0054] (2) Phenyl dichlorophosphate and tetrahydrofuran are mixed and stirred uniformly to obtain a phenyl dichlorophosphate solution; the concentration of the phenyl dichlorophosphate solution is 2 mol / L.

[0055] Mix 0.1 mol of hydroxyethyl acrylate, 0.2 mol of triethylamine and 100 mL of tetrahydrofuran, stir evenly, add 0.12 mol of phenyl dichlorophosphate solution under ice-water bath, react at 0°C for 10 h, then add 0.1 mol of thiol monomer, react at 60°C for 4 h, collect the product, and purify it to obtain a phosphate monomer containing a thiol group.

[0056] Step S3: 0.3 mol of pentaerythritol tetrakis(3-mercaptopropionate), 0.4 mol of pentaerythritol triacrylate, 0.12 mol of perfluorodecanethiol and 0.12 mol of a flame retardant monomer containing a double bond are mixed, a photoinitiator is added, and the mixture is stirred evenly to obtain a coating material; the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator used is 2.5 wt% of the total mass of the coating material.

[0057] Step S4: The surface of the wood veneer is polished and smoothed, ultrasonically cleaned with deionized water, and vacuum dried at 60° C. for 12 hours. The coating material is then evenly applied to the surface of the wood veneer and cured under ultraviolet light (λ=365 nm) for 5 minutes to obtain a flame-retardant wood veneer; the coating material coating thickness is 0.3 mm.

[0058] Glue is applied to the surface of several flame retardant wood veneers, stacked and assembled, and hot pressed to form a composite floor. The amount of glue applied on one side is 120g / m 2 .

[0059] Comparative Example 1: A method for preparing a flame-retardant laminated solid wood composite floor, comprising the following steps:

[0060] Step S1: The preparation step of the flame retardant monomer containing a double bond is as follows: phenyl dichlorophosphate and tetrahydrofuran are mixed and stirred uniformly to obtain a phenyl dichlorophosphate solution; the concentration of the phenyl dichlorophosphate solution is 2 mol / L.

[0061] Mix 0.21 mol of hydroxyethyl acrylate, 0.2 mol of triethylamine and 100 mL of tetrahydrofuran, stir evenly, add 0.12 mol of phenyl dichlorophosphate solution under ice-water bath, react at 0°C for 10 h, then add 0.1 mol of mercapto monomer, react at 60°C for 4 h, collect the product, and purify it to obtain a flame retardant monomer containing a double bond.

[0062] Step S2: Add a photoinitiator to 0.3 mol of pentaerythritol tetrakis(3-mercaptopropionate), 0.4 mol of pentaerythritol triacrylate, 0.2 mol of perfluorodecanethiol and 0.1 mol of a flame retardant monomer containing a double bond, and stir evenly to obtain a coating material; the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator is 2.5 wt% of the total mass of the coating material.

[0063] Step S3: The surface of the wood veneer is polished and smoothed, ultrasonically cleaned with deionized water, and vacuum dried at 60°C for 12 hours. The coating material is then evenly applied to the surface of the wood veneer and cured under ultraviolet light (λ=365nm) for 5 minutes to obtain a flame-retardant wood veneer; the coating material coating thickness is 0.3 mm.

[0064] Glue is applied to the surface of several flame retardant wood veneers, stacked and assembled, and hot pressed to form a composite floor. The amount of glue applied on one side is 120g / m 2 .

[0065] Example 3 was used as a control group, and no dopamine monomer was introduced into Comparative Example 1.

[0066] Comparative Example 2: A method for preparing a flame-retardant laminated solid wood composite floor, comprising the following steps:

[0067] Step S1: 47.5 mmol of sodium carbonate, 16.2 mmol of sodium borate decahydrate and 300 mL of deionized water were mixed, nitrogen was introduced to deoxygenate, 16.2 mmol of dopamine hydrochloride was added under nitrogen, and the mixture was stirred evenly. Then, 16.2 mmol of acryloyl chloride was added, and sodium carbonate was added to maintain the pH at 9. The mixture was reacted at 30° C. for 12 h. After the reaction, the pH was adjusted to 1 with hydrochloric acid, the mixture was extracted with ethyl acetate, dried over anhydrous copper sulfate, and recrystallized to obtain dopamine monomer.

[0068] Step S2: Nitrogen is introduced into anhydrous methanol to remove oxygen, 0.2 mol of dopamine monomer is added under nitrogen environment, and the mixture is stirred and dissolved. Then, 0.1 mol of phosphate monomer containing a mercapto group and a photoinitiator are added. Under ultraviolet light (λ = 365 nm), the mixture is stirred and reacted for 0.5 h. After the reaction, the solvent is removed to obtain a flame retardant monomer containing a double bond; the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator used is 2 wt% of the total mass of the phosphate monomer containing a mercapto group and the dopamine monomer.

[0069] The preparation steps of the phosphate monomer containing mercapto group are as follows:

[0070] (1) 0.1 mol of trimethylolpropane, 0.21 mol of mercaptopropionic acid, a catalyst and toluene were mixed and reacted for 4 h under nitrogen at a temperature of 70°C. After the reaction, the mixture was washed with water and the organic solvent was removed by distillation to obtain a mercapto monomer; the catalyst was p-toluenesulfonic acid, and the amount of the catalyst was 2.5 wt% of the total mass of trimethylolpropane and mercaptopropionic acid.

[0071] (2) Phenyl dichlorophosphate and tetrahydrofuran are mixed and stirred uniformly to obtain a phenyl dichlorophosphate solution; the concentration of the phenyl dichlorophosphate solution is 2 mol / L.

[0072] Mix 0.1 mol of hydroxyethyl acrylate, 0.2 mol of triethylamine and 100 mL of tetrahydrofuran, stir evenly, add 0.12 mol of phenyl dichlorophosphate solution under ice-water bath, react at 0°C for 10 h, then add 0.1 mol of thiol monomer, react at 60°C for 4 h, collect the product, and purify it to obtain a phosphate monomer containing a thiol group.

[0073] Step S3: 0.33 mol of pentaerythritol tetrakis(3-mercaptopropionate), 0.4 mol of pentaerythritol triacrylate, and 0.12 mol of a flame retardant monomer containing a double bond are mixed, a photoinitiator is added, and the mixture is stirred evenly to obtain a coating material; the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator used is 2.5 wt% of the total mass of the coating material.

[0074] Step S4: The surface of the wood veneer is polished and smoothed, ultrasonically cleaned with deionized water, and vacuum dried at 60° C. for 12 hours. The coating material is then evenly applied to the surface of the wood veneer and cured under ultraviolet light (λ=365 nm) for 5 minutes to obtain a flame-retardant wood veneer; the coating material coating thickness is 0.3 mm.

[0075] Glue is applied to the surface of several flame retardant wood veneers, stacked and assembled, and hot pressed to form a composite floor. The amount of glue applied on one side is 120g / m 2 .

[0076] Example 3 was used as a control group, and perfluorodecanethiol was not introduced into Comparative Example 2.

[0077] Comparative Example 3: A method for preparing a flame-retardant laminated solid wood composite floor, comprising the following steps:

[0078] Step S1: 0.3 mol of pentaerythritol tetrakis(3-mercaptopropionate) and 0.4 mol of pentaerythritol triacrylate are mixed, a photoinitiator is added, and the mixture is stirred evenly to obtain a coating material; the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator used is 2.5 wt% of the total mass of the coating material.

[0079] Step S2: The surface of the wood veneer is polished and smoothed, ultrasonically cleaned with deionized water, and vacuum dried at 60° C. for 12 hours. The coating material is then evenly applied to the surface of the wood veneer and cured under ultraviolet light (λ=365 nm) for 5 minutes to obtain a flame-retardant wood veneer; the coating material has a coating thickness of 0.3 mm.

[0080] Glue is applied to the surface of several flame retardant wood veneers, stacked and assembled, and hot pressed to form a composite floor. The amount of glue applied on one side is 120g / m 2 .

[0081] Example 3 was used as a control group, in which a film was formed by photocuring only pentaerythritol tetrakis(3-mercaptopropionate) and pentaerythritol triacrylate.

[0082] Detection experiment:

[0083] According to the methods disclosed in Examples 1 to 3 and Comparative Examples 1 to 3, flame-retardant wood veneer samples were prepared.

[0084] 1. Use an oxygen index meter to test the limiting oxygen index. The test method refers to ASTM D2863. The sample size is 130 mm × 6.5 mm × 3 mm.

[0085] 2. Refer to the method disclosed in ASTM D3359-17 and use a grid knife to test the adhesion performance of the coating to the wood veneer. During the test, the grid knife penetrates the surface coating and cuts perpendicularly to the wood veneer at a constant speed of 20 mm / s to form a matrix shape. Then, a pressure-sensitive tape is attached to the matrix shape and the tape is peeled off in the opposite direction. The coating shedding is observed and the adhesion is rated. The grades are 0B, 1B, 2B, 3B, 3B, 4B, and 5B.

[0086] 3. Test the water contact angle on the surface of the flame retardant wood veneer sample.

[0087] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Limiting oxygen index 27.8 28.1 28.5 25.4 28.4 22.3 Adhesion rating 4B 4B 4B 2B 4B 1B Water contact angle 96.7° 98.4° 101.2° / 68.4° /

[0088] Conclusion: The present invention discloses a method for preparing flame-retardant laminated solid wood composite flooring, which produces a wood veneer with excellent flame-retardant properties. The wood veneer is coated with glue and then laminated and hot-pressed to produce a composite flooring with excellent comprehensive performance. The composite flooring can be widely used in home decoration and other fields and has high practicality.

[0089] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a flame-retardant laminated solid wood composite floor, characterized by: The following steps are involved: Step S1: Sodium carbonate, sodium borate decahydrate and deionized water are mixed, nitrogen is introduced to remove oxygen, dopamine hydrochloride is added under nitrogen, and the mixture is stirred evenly. Acryloyl chloride is then added, and sodium carbonate is added to maintain the pH at 8-9. The mixture is reacted at 25-30° C. for 12-14 hours. After the reaction is completed, the pH is adjusted to 1 with hydrochloric acid, and the mixture is extracted with ethyl acetate, dried over anhydrous copper sulfate, and recrystallized to obtain a dopamine monomer. Step S2: nitrogen is introduced into anhydrous methanol to remove oxygen, dopamine monomer is added under nitrogen atmosphere, stirred and dissolved, and then a phosphate monomer containing a mercapto group and a photoinitiator are added. Under ultraviolet light, the mixture is stirred and reacted for 0.5 to 1 hour. After the reaction is completed, the solvent is removed to obtain a flame retardant monomer containing a double bond; Step S3: Pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol triacrylate, perfluorodecanethiol and a flame retardant monomer containing a double bond are mixed, a photoinitiator is added, and the mixture is stirred evenly to obtain a coating material; Step S4: polishing the surface of the wood veneer, ultrasonically cleaning with deionized water, vacuum drying at 60°C for 12 hours, then evenly applying the coating material to the surface of the wood veneer, and curing under ultraviolet light for 3-5 minutes to obtain a flame-retardant wood veneer; Glue is applied on the surfaces of several flame-retardant wooden veneers respectively, the boards are laminated and hot-pressed to form a composite floor.

2. The method for preparing a flame-retardant laminated solid wood composite floor according to claim 1, characterized in that: In step S3, the molar ratio of pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol triacrylate, perfluorodecanethiol, and flame retardant monomer containing a double bond is 3:4:(1-1.2):(1-1.2); the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator used is 2-2.5wt% of the total mass of the coating material.

3. The method for preparing a flame-retardant laminated solid wood composite floor according to claim 1, wherein: In step S1, the molar ratio of dopamine hydrochloride to acryloyl chloride is 1:1; the molar ratio of dopamine hydrochloride to sodium borate decahydrate is 1:

1.

4. The method for preparing a flame-retardant laminated solid wood composite floor according to claim 1, wherein: In step S2, the preparation steps of the thiol-containing phosphate monomer are as follows: (1) Trimethylolpropane, mercaptopropionic acid, a catalyst and toluene are mixed and reacted under nitrogen for 3-4 hours at a temperature of 70-80°C. After the reaction, the mixture is washed with water and the organic solvent is removed by distillation to obtain a mercapto monomer; (2) mixing phenyl dichlorophosphate and tetrahydrofuran, and stirring uniformly to obtain a phenyl dichlorophosphate solution; Mix hydroxyethyl acrylate, triethylamine and tetrahydrofuran, stir evenly, add phenyl dichlorophosphate solution under ice-water bath, react at 0°C for 8-10 hours, then add thiol monomer, react at 50-60°C for 4-6 hours, collect the product, and purify it to obtain a phosphate monomer containing a thiol group.

5. The method for preparing a flame-retardant laminated solid wood composite floor according to claim 4, characterized in that: The molar ratio of trimethylolpropane to mercaptopropionic acid is 1:(2.1-2.3); the catalyst is p-toluenesulfonic acid, and the amount of the catalyst used is 2.5-3 wt% of the total mass of trimethylolpropane and mercaptopropionic acid.

6. The method for preparing a flame-retardant laminated solid wood composite floor according to claim 4, characterized in that: The concentration of the phenyl dichlorophosphate solution is 2-3 mol / L; the molar ratio of the hydroxyethyl acrylate, phenyl dichlorophosphate, and mercapto monomer is 1:(1-1.2):1; and the molar ratio of the hydroxyethyl acrylate and triethylamine is 1:

2.

7. The method for preparing a flame-retardant laminated solid wood composite floor according to claim 1, wherein: In step S2, the molar ratio of the thiol-containing phosphate monomer and the dopamine monomer is 1:2; the photoinitiator is benzoin dimethyl ether, and the amount of the photoinitiator is 1.5-2.5 wt% of the total mass of the thiol-containing phosphate monomer and the dopamine monomer.

8. The method for preparing a flame-retardant laminated solid wood composite floor according to claim 1, wherein: In step S4, the coating thickness is 0.2-0.4 mm; the amount of glue applied on one side is 120 g / m 2 .

9. The method for preparing a flame-retardant laminated solid wood composite floor according to claim 1, characterized in that: The wooden veneer is any one of poplar, eucalyptus and pine.

10. A solid wood composite floor prepared according to the method for preparing a flame-retardant laminated solid wood composite floor according to any one of claims 1 to 9.