Flame-retardant recombined decorative material and preparation method thereof

Abstract

The invention provides a flame-retardant recombined decorative material and a preparation method thereof, and the preparation method comprises the following steps: applying a melamine modified urea-formaldehyde resin adhesive added with a certain amount of filler of nano montmorillonite and hydrotalcite in a certain proportion to poplar veneers, assembling, and then cold-pressing to obtain a first group of battens, and then slicing the first group of battens into recombined veneers with a certain thickness. A flame-retardant melamine modified urea-formaldehyde resin adhesive is synthesized through cyclodextrin, formaldehyde, urea and melamine, the recombined veneer is coated with the adhesive according to a certain amount, then cold pressing is conducted for a period of time after assembly is conducted, a recombined batten is obtained, and the recombined batten is sliced to obtain the flame-retardant recombined decorative material. The problems that a traditional flame-retardant recombined decorative material is poor in bonding strength and smoke suppression performance, and glue spots exist on the surface are solved.

Description

Technical Field

[0001] The present invention relates to the field of artificial boards, and in particular to a flame-retardant reconstituted decorative material and a preparation method thereof. Background Art

[0002] With the increasing safety requirements for interior decoration in public buildings and residential buildings, flame-retardant wood decorative materials are gaining increasing attention. While traditional flame-retardant reconstituted decorative materials can improve the flame retardancy of wood to a certain extent, they still have significant deficiencies in terms of bonding strength, smoke emission control, and surface decorative properties. For one thing, conventional flame retardants lack compatibility with adhesive systems, resulting in reduced bonding strength. Furthermore, some organic flame retardants readily decompose at high temperatures, producing toxic fumes and limiting their smoke suppression effectiveness. Furthermore, due to the tendency of flame retardant particles to agglomerate and become unevenly distributed, decorative defects such as adhesive spots often appear on the surface of the board, severely impacting the material's usability and visual appeal.

[0003] Prior patent documents

[0004] CN 117701207 A

[0005] CN 108659760 B Summary of the Invention

[0006] The present invention is developed in view of the above-mentioned problems, and its purpose is to provide a flame-retardant recombinant decorative material and a preparation method thereof. The flame-retardant system of nanoparticles and cyclodextrin and a two-step recombinant process design are adopted to achieve excellent flame retardancy while effectively solving the problems of poor smoke suppression, low bonding strength and glue spots in traditional processes.

[0007] First, a method for preparing a flame-retardant reconstituted decorative material is provided, which comprises:

[0008] (1): Prepare inorganic filler adhesive and flame retardant adhesive, wherein,

[0009] (1-1) The inorganic filler adhesive is prepared by the following method:

[0010] The nano-montmorillonite and nano-hydrotalcite are mixed uniformly in a mass ratio of 1:1-1.5, added to a melamine-modified urea-formaldehyde resin having a melamine content of 8-11% and a solid content of 50-55% at a mass ratio of 25-30:100, and stirred at room temperature for 5-8 hours to obtain an inorganic filler adhesive;

[0011] (1-2) The flame retardant adhesive is prepared by the following method:

[0012] Adding a 37-40% formaldehyde aqueous solution into a reactor, adding a certain amount of NaOH solution to adjust the pH value to 8.4-8.6, then adding the first batch of urea, the first batch of melamine and cyclodextrin, raising the temperature to 70-80° C. and maintaining it for 1-2.5 hours, wherein the molar ratio of formaldehyde to the first batch of urea is 0.9-0.96:0.45-0.55, the melamine accounts for 25-35% of the mass of the formaldehyde, and the cyclodextrin accounts for 30-55% of the mass of the formaldehyde;

[0013] Then, a second batch of urea and a second batch of melamine were added, and the pH value was adjusted to 6.5-6.7 with a formic acid solution. The temperature was maintained at 70-80°C for 1-2.5 hours. Then, a certain amount of NaOH solution was used to adjust the pH value to 8.5-8.7, wherein the molar ratio of formaldehyde to the second batch of urea was 0.9-0.96:0.45-0.55, and the second batch of melamine accounted for 8-12% of the mass of the formaldehyde. Heating was stopped and the temperature was allowed to cool to room temperature to obtain a flame retardant adhesive.

[0014] (2): Preparation of flame retardant reconstituted decorative materials:

[0015] (2-1) Apply the inorganic filler adhesive to the surface of the wood veneer with a certain or different thickness, with a coating amount of 110-125g / m 2 , assembling the plurality of glued veneers and then cold pressing them, with a cold pressing pressure of 0.20-0.25 MPa and a cold pressing time of 168-180 h to obtain a first group of wood squares;

[0016] (2-2) Slice the first group of wood along any side into reconstructed veneers of certain or different thicknesses, and then apply flame retardant adhesive on the surface of each reconstructed veneer with a coating amount of 110-125g / m 2 , assembling the plurality of veneers after gluing and then cold pressing them, the cold pressing pressure is 0.20-0.25MPa, the cold pressing time is 168-180h, to obtain the second group of wood squares;

[0017] (2-3) The second set of wood is sliced ​​along any side into 0.40-0.60 mm thick veneers to obtain flame retardant reconstituted decorative materials.

[0018] In the above (1-1), the average particle size of the nano-montmorillonite is 50-70 nm, and the average particle size of the nano-hydrotalcite is 50-70 nm.

[0019] In the above (2-1), the wood veneer is any one of poplar, eucalyptus, pine or a combination thereof with a thickness of 1.7-1.8 mm and a moisture content of 8-10%.

[0020] In the above (2-1), the glued wood veneers are assembled into blanks with a thickness of 1.2-1.5m.

[0021] In the above (2-2), the first group of wood blocks are sliced ​​into reconstituted veneers with a thickness of 1.0-1.2 mm.

[0022] In the above (2-2), the glue-coated reconstituted veneer is assembled into a thickness of 1.2-1.5m.

[0023] In the method (2-1), the blanks are assembled along the direction of the wood grain, and in the method (2-2), the blanks are assembled along the direction of the layer grain.

[0024] The (2-3) is sliced ​​along the side of the grid.

[0025] Also provided is a flame retardant recombinant decorative material prepared by any of the above preparation methods.

[0026] According to the present invention, the following beneficial effects can be obtained.

[0027] (1) Smoke suppression performance is significantly improved: Based on the synergistic effect of inorganic nanoparticles and cyclodextrin, nano-montmorillonite and hydrotalcite are introduced into melamine-modified urea-formaldehyde resin adhesive, and work together with the cyclodextrin groups in the synthetic adhesive: inorganic nanoparticles form a stable inert barrier layer at high temperature, effectively blocking heat conduction and combustible gas release; the cyclodextrin structure produces a nitrogen-rich carbon layer and gas (such as ammonia and nitrogen) during the pyrolysis process, which dilutes the oxygen concentration in the combustion area at the initial stage of flame spread; the two work together to form a dense and stable "expanded carbon layer", which significantly suppresses the release of smoke and toxic gases, meeting the safety requirements of modern decorative materials for low smoke and environmental protection.

[0028] (2) Two-step recombination process: the key path to improving structural stability and flame retardant efficiency

[0029] Compared with the traditional one-step pressing method, the present invention adopts a two-step method of "first slicing into reconstituted veneer + reconstitution and gluing and pressing", which has the following advantages: the first step of reconstitution and slicing can evenly distribute the nanoparticles and the primary bonding interface, thereby improving the structural density; the second step uses flame-retardant adhesive for reconstitution to ensure that the flame-retardant components are concentrated in the key adhesive layer, further enhancing the overall flame retardant effect; the process is conducive to reducing internal stress accumulation, improving dimensional stability and yield rate.

[0030] (3) Eliminating adhesive spot defects - the dispersion promotion effect of nanoparticles

[0031] Nano-scale montmorillonite and hydrotalcite provide a good dispersion interface through their layered structure, significantly improving the spreading performance of the adhesive on the wood surface; during the planing and re-pressing process, the particles can act as rheology regulators and interface modifiers to prevent the migration and aggregation of cyclodextrin components in the flame retardant adhesive; through the dispersion effect, they can effectively eliminate surface defects such as glue spots and color spots, thereby improving the decorative effect.

[0032] (4) Improved bonding strength - the reaction mechanism between the flame retardant structure and the adhesive molecular chain. The flame retardant is copolymerized by cyclodextrin, melamine, urea and formaldehyde, and has multifunctional groups (-NH2, -OH, -C=N); these groups can form a cross-linking reaction with the urea-formaldehyde resin network during the curing process and embed into the molecular chain to form a dense adhesive network structure; the increased cross-linking degree enhances the cohesive strength and heat resistance stability of the adhesive layer. While flame retardant modification is performed, the bonding strength is maintained or even improved, overcoming the bottleneck problem of "strength sacrifice" often caused by flame retardant modification. DETAILED DESCRIPTION

[0033] The following describes embodiments of the present invention. However, the present invention is not limited to these embodiments and may be modified in various ways within the scope of the claims. New modifications obtained by combining different embodiments or preparation examples, as well as conventional technical means, are also considered to be within the scope of the present invention.

[0034] Raw materials:

[0035] Nano-montmorillonite: purchased from Jingjiang Kanggaote New Material Technology Co., Ltd.;

[0036] Nano-hydrotalcite: purchased from Jingjiang Kanggaote New Material Technology Co., Ltd.;

[0037] Melamine-modified urea-formaldehyde resin: purchased from Guangxi Jianxin Wood Industry Group Co., Ltd.

[0038] Cyclodextrin: purchased from Shandong Tongwang Biotechnology Co., Ltd.

[0039] This embodiment uses a novel cyclodextrin-modified melamine urea-formaldehyde resin flame-retardant adhesive to prepare a flame-retardant reconstituted decorative material. The preparation comprises: adding a formaldehyde aqueous solution having a mass concentration of 37-40% to a reactor, adding urea in two equal or nearly equal amounts, with a molar ratio of the total amount of formaldehyde to urea being 0.9-0.96:1, and adding melamine / cyclodextrin along with the urea.

[0040] The preparation further comprises: adding the above-mentioned formaldehyde aqueous solution into a reaction kettle, adding a certain amount of NaOH solution to adjust the pH value to 8.4-8.6, then adding the first batch of urea (accounting for 45-55% of the total mass of urea), melamine (accounting for 25-35% of the mass of formaldehyde) and cyclodextrin (accounting for 30-55% of the mass of formaldehyde), heating to 70-80°C and maintaining for 1-2.5 hours;

[0041] A second batch of urea (accounting for 45-55% of the total mass of urea) and melamine (accounting for 8-12% of the mass of formaldehyde) are added, the pH value is adjusted to 6.5-6.7 with formic acid solution, and the mixture is maintained at 70-80°C for 1-2.5 hours. Then, a certain amount of NaOH solution is used to adjust the pH value to 8.5-8.7. The heating is stopped and the reaction is stopped after the temperature drops to room temperature to obtain a flame retardant adhesive.

[0042] The following reactions occur in the above preparation.

[0043] Preparation Example 1:

[0044] A 37% formaldehyde aqueous solution was added to a reactor, and a certain amount of a 35% NaOH aqueous solution was added to adjust the pH value to 8.6. Then, the first batch of urea (accounting for 45% of the total mass of urea, and the molar ratio of formaldehyde to the first batch of urea was 0.9:0.45), melamine (accounting for 25% of the mass of the formaldehyde solution) and cyclodextrin (accounting for 30% of the mass of the formaldehyde solution) were added, and the temperature was raised to 80°C and maintained for 2.5 hours;

[0045] A second batch of urea (accounting for 55% of the total mass of urea, the molar ratio of formaldehyde to the second batch of urea is 0.9:0.55) and melamine (accounting for 8% of the mass of the formaldehyde solution) are added, and the pH value is adjusted to 6.7 with a certain amount of 20% mass concentration formic acid aqueous solution, maintained at 80°C for 2.5 hours, and then the pH value is adjusted to 8.7 with a certain amount of 35% mass concentration NaOH aqueous solution. Heating is stopped and the reaction is stopped after the temperature drops to room temperature 25°C to obtain a flame retardant adhesive.

[0046] Preparation Example 2:

[0047] A 40% formaldehyde aqueous solution was added to a reactor, and a certain amount of a 35% NaOH aqueous solution was added to adjust the pH value to 8.4. Then, the first batch of urea (accounting for 55% of the total mass of urea, the molar ratio of formaldehyde to the first batch of urea was 0.96:0.55), melamine (accounting for 35% of the mass of the formaldehyde solution) and cyclodextrin (accounting for 55% of the mass of the formaldehyde solution) were added, and the temperature was raised to 70°C and maintained for 1 hour;

[0048] A second batch of urea (accounting for 45% of the total mass of urea, the molar ratio of formaldehyde to the second batch of urea is 0.96:0.45) and melamine (accounting for 12% of the mass of the formaldehyde solution) are added, and the pH value is adjusted to 6.5 with a certain amount of 20% mass concentration formic acid aqueous solution, maintained at 70°C for 1 hour, and then the pH value is adjusted to 8.5 with a certain amount of 35% mass concentration NaOH aqueous solution. Heating is stopped and the reaction is stopped after the temperature drops to room temperature 25°C to obtain a flame retardant adhesive.

[0049] Preparation Example 3:

[0050] A 37% formaldehyde aqueous solution was added to a reactor, and a certain amount of a 35% NaOH aqueous solution was added to adjust the pH value to 8.4. Then, the first batch of urea (accounting for 50% of the total mass of urea, the molar ratio of formaldehyde to the first batch of urea was 0.93:0.5), melamine (accounting for 30% of the mass of the formaldehyde solution) and cyclodextrin (accounting for 40% of the mass of the formaldehyde solution) were added, and the temperature was raised to 75°C and maintained for 2 hours;

[0051] A second batch of urea (accounting for 50% of the total mass of urea, the molar ratio of formaldehyde to the second batch of urea is 0.93:0.5) and melamine (accounting for 10% of the mass of the formaldehyde solution) are added, and the pH value is adjusted to 6.5 with a certain amount of 20% mass concentration formic acid aqueous solution, maintained at 75°C for 2h, and then the pH value is adjusted to 8.5 with a certain amount of 35% mass concentration NaOH aqueous solution. Heating is stopped and the reaction is stopped after the temperature drops to room temperature 25°C to obtain a flame retardant adhesive.

[0052] This embodiment further uses the flame-retardant adhesive prepared in Preparation Examples 1 to 3 to prepare a flame-retardant reconstituted decorative material, and the specific preparation is as follows.

[0053] (1) Nano-montmorillonite and nano-hydrotalcite are mixed uniformly in a mass ratio of 1:1-1.5, and added to a melamine-modified urea-formaldehyde resin with a melamine content of 8-11% and a solid content of 50-55%. The addition mass ratio (inorganic seasoning to urea-formaldehyde resin mass ratio) is 25-30:100. After stirring at room temperature for 5-8 hours, an inorganic filler adhesive is obtained.

[0054] (2) Apply the above inorganic filler adhesive to the surface of wood veneer with a certain or different thickness, with a coating amount of 110-125g / m 2 , assemble the multiple veneers after gluing along the same wood grain direction and then perform cold pressing treatment, the cold pressing pressure is 0.20-0.25MPa, the cold pressing time is 168-180h, and the first group of wood squares is obtained.

[0055] (3) Slice the first group of wood along any side into reconstructed veneers of certain or different thicknesses, and then apply flame retardant adhesive on the surface of each reconstructed veneer with a coating amount of 110-125g / m 2 The multiple veneers after gluing are assembled along the same layer grain direction and then cold pressed with a cold pressing pressure of 0.20-0.25 MPa and a cold pressing time of 168-180 h to obtain the second group of wood squares.

[0056] (4) Slice the second set of wood along any side (preferably along the grid pattern side) into veneers with a thickness of 0.40-0.60 mm to obtain flame-retardant reconstituted decorative materials.

[0057] The average particle size of the nano-montmorillonite is 50-70 nm, and the average particle size of the nano-hydrotalcite is 50-70 nm. The wood veneer is 1.7-1.8 mm thick and made of poplar, eucalyptus, pine, or other wood with a moisture content of 8-10%. The glued wood veneer is assembled to a thickness of 1.2-1.5 μm, and the first set of wood blocks is sliced ​​into reconstituted veneers with a thickness of 1.0-1.2 mm. The glued reconstituted veneers are assembled to a thickness of 1.2-1.5 μm.

[0058] Embodiment 1:

[0059] (1) Nano-montmorillonite with an average particle size of 50-70 nm and nano-hydrotalcite with an average particle size of 50-70 nm were mixed uniformly in a mass ratio of 1:1, and added to a melamine-modified urea-formaldehyde resin with a melamine content of 8% and a solid content of 50% at a mass ratio of 25:100. After stirring at room temperature of 25°C for 5 h, an inorganic filler adhesive was obtained.

[0060] (2) The inorganic filler adhesive was applied to the surface of a 1.7 mm thick, 2.2 m long (in the direction of wood grain), and 1.2 m wide poplar veneer with a moisture content of 8%. The amount of adhesive applied was 110 g / m 2 , multiple veneers after gluing are assembled in the same wood grain direction to a thickness of 1.2m, and then cold pressed with a cold pressing pressure of 0.20MPa and a cold pressing time of 168h to obtain the first group of wood squares.

[0061] (3) The first group of wood was sliced ​​into 1.0 mm reconstructed veneers along the width, side and thickness of the same size, and then the flame retardant adhesive of Preparation Example 1 was coated on the surface of each reconstructed veneer, with a coating amount of 110 g / m 2 The multiple veneers after gluing are assembled along the same layer grain direction to a thickness of 1.2m, and then cold pressed with a cold pressing pressure of 0.20MPa and a cold pressing time of 168h to obtain the second group of wood squares.

[0062] (4) The second group of wood blocks is sliced ​​along the sides of the long stripes into 0.40 mm thick veneers to obtain flame retardant reconstituted decorative materials.

[0063] performance:

[0064] Peak heat release rate: 105.7kW / m 2

[0065] Peak smoke release rate: 0.0164m 2 / s

[0066] Flame retardant reconstituted decorative material transverse curvature: 0.089%

[0067] Number of visible adhesive inclusions per square meter (tested according to GB / T 28998-2012): 0

[0068] Example 2:

[0069] (1) Nano-montmorillonite with an average particle size of 50-70 nm and nano-hydrotalcite with an average particle size of 50-70 nm were mixed uniformly in a mass ratio of 1:1.5, and added to a melamine-modified urea-formaldehyde resin with a melamine content of 11% and a solid content of 55% at a mass ratio of 30:100. After stirring at room temperature of 25°C for 8 h, an inorganic filler adhesive was obtained.

[0070] (2) The inorganic filler adhesive was applied to the surface of eucalyptus veneer with a moisture content of 10% and a thickness of 1.8 mm, a length of 2.2 m (in the direction of wood grain), and a width of 1.2 m. The amount of adhesive applied was 125 g / m 2 , multiple veneers after gluing are assembled in the same wood grain direction to a thickness of 1.5m, and then cold pressed with a cold pressing pressure of 0.25MPa and a cold pressing time of 180h to obtain the first group of wood squares.

[0071] (3) The first group of wood was sliced ​​into 1.2 mm reconstructed veneers along the width, side and thickness of the same size, and then the flame retardant adhesive of Preparation Example 2 was coated on the surface of each reconstructed veneer, with a coating amount of 125 g / m 2 The multiple veneers after gluing are assembled along the same layer grain direction to a thickness of 1.5m, and then cold pressed with a cold pressing pressure of 0.25MPa and a cold pressing time of 180h to obtain the second group of wood squares.

[0072] (4) The second group of wood blocks are sliced ​​along the sides of the long stripes into 0.6 mm thick veneers to obtain flame retardant reconstituted decorative materials.

[0073] performance:

[0074] Peak heat release rate: 91.8kW / m 2

[0075] Peak smoke release rate: 0.0159m 2 / s

[0076] Flame retardant reconstituted decorative material transverse curvature: 0.081%

[0077] Number of visible adhesive inclusions per square meter (tested according to GB / T 28998-2012): 0

[0078] Example 3:

[0079] (1) Nano-montmorillonite with an average particle size of 50-70 nm and nano-hydrotalcite with an average particle size of 50-70 nm were mixed uniformly in a mass ratio of 1:1.2, and added to a melamine-modified urea-formaldehyde resin with a melamine content of 10% and a solid content of 52% at a mass ratio of 28:100. After stirring at room temperature of 25°C for 9 hours, an inorganic filler adhesive was obtained.

[0080] (2) The inorganic filler adhesive was applied to the surface of a 1.7 mm thick, 2.2 m long (in the direction of wood grain), and 1.2 m wide poplar veneer with a moisture content of 9%, with a coating amount of 120 g / m 2 , multiple veneers after gluing are assembled with the same wood grain to a thickness of 1.2m, and then cold pressed with a cold pressing pressure of 0.2MPa and a cold pressing time of 168h to obtain the first group of wood squares.

[0081] (3) The first group of wood was sliced ​​into 1.2 mm thick reconstituted veneers along the length side, and then the flame retardant adhesive of Preparation Example 3 was coated on the surface of each reconstituted veneer, with a coating amount of 120 g / m 2 The multiple veneers after gluing are assembled along the same layer grain direction to a thickness of 1.2m, and then cold pressed with a cold pressing pressure of 0.2MPa and a cold pressing time of 168h to obtain the second group of wood squares.

[0082] (4) The second group of wood blocks is sliced ​​along the sides of the long stripes into 0.4 mm thick veneers to obtain flame retardant reconstituted decorative materials.

[0083] performance:

[0084] Peak heat release rate: 97.1kW / m 2

[0085] Peak smoke release rate: 0.0162m 2 / s

[0086] Flame retardant recombinant decoration transverse curvature: 0.086%

[0087] Number of visible adhesive inclusions per square meter (tested according to GB / T 28998-2012): 0

[0088] A control experiment was carried out based on Example 3 to obtain the following comparative example.

[0089] Comparative Example 1:

[0090] The difference between Comparative Example 1 and Example 3 is that:

[0091] (1) Instead of using inorganic filler adhesive, it is replaced by homologous melamine-modified urea-formaldehyde resin;

[0092] (2) No cyclodextrin is added in the preparation of the flame retardant adhesive.

[0093] performance:

[0094] Peak heat release rate: 154.1kW / m 2

[0095] Peak smoke release rate: 0.0292m 2 / s

[0096] Flame retardant recombinant decoration transverse curvature: 1.116%

[0097] Number of visible adhesive inclusions per square meter (tested according to GB / T 28998-2012): 0

[0098] Comparative Example 2:

[0099] The difference between Comparative Example 2 and Example 3 is that:

[0100] No cyclodextrin is added in the preparation of the flame retardant adhesive.

[0101] performance:

[0102] Peak heat release rate: 141.9kW / m 2

[0103] Peak smoke release rate: 0.0211m 2 / s

[0104] Flame retardant recombinant decorative transverse curvature: 1.006%

[0105] Number of visible adhesive inclusions per square meter (tested according to GB / T 28998-2012): 0

[0106] Comparative Example 3:

[0107] The difference between Comparative Example 3 and Example 3 is that:

[0108] Instead of using inorganic filler adhesive, it is replaced by homologous melamine-modified urea-formaldehyde resin.

[0109] performance:

[0110] Peak heat release rate: 149.1kW / m 2

[0111] Peak smoke release rate: 0.0251m 2 / s

[0112] Flame retardant recombinant decorative transverse curvature: 1.102%

[0113] Number of visible adhesive inclusions per square meter (tested according to GB / T 28998-2012): 5

[0114] Comparative Example 4:

[0115] The difference between Comparative Example 4 and Example 3 is that:

[0116] In the preparation of flame retardant adhesives, cyclodextrin is added in the form of a blend without reacting, that is:

[0117] A formaldehyde aqueous solution with a mass concentration of 37% was added into a reactor, and then urea (the molar ratio of formaldehyde to urea was 0.93:1), melamine (accounting for 60% of the mass of the formaldehyde solution) and cyclodextrin (accounting for 40% of the mass of the formaldehyde solution) were added and blended to obtain a blended flame retardant adhesive.

[0118] performance:

[0119] Peak heat release rate: 131.1kW / m 2

[0120] Peak smoke release rate: 0.0212m 2 / s

[0121] Flame retardant recombinant decorative transverse curvature: 1.112%

[0122] The number of visible adhesive inclusions per square meter (tested according to GB / T 28998-2012): 7.

Claims

1. A method for preparing a flame retardant reconstituted decorative material, characterized in that: include: (1): Prepare inorganic filler adhesive and flame retardant adhesive, wherein, (1-1) The inorganic filler adhesive is prepared by the following method: The nano-montmorillonite and nano-hydrotalcite are mixed uniformly in a mass ratio of 1:1-1.5, added to a melamine-modified urea-formaldehyde resin having a melamine content of 8-11% and a solid content of 50-55% at a mass ratio of 25-30:100, and stirred at room temperature for 5-8 hours to obtain an inorganic filler adhesive; (1-2) The flame retardant adhesive is prepared by the following method: Adding a 37-40% formaldehyde aqueous solution into a reactor, adding a certain amount of NaOH solution to adjust the pH value to 8.4-8.6, then adding the first batch of urea, the first batch of melamine and cyclodextrin, raising the temperature to 70-80° C. and maintaining it for 1-2.5 hours, wherein the molar ratio of formaldehyde to the first batch of urea is 0.9-0.96:0.45-0.55, the melamine accounts for 25-35% of the mass of the formaldehyde solution, and the cyclodextrin accounts for 30-55% of the mass of the formaldehyde solution; Then, a second batch of urea and a second batch of melamine were added, and the pH value was adjusted to 6.5-6.7 with a formic acid solution. The temperature was maintained at 70-80°C for 1-2.5 hours. Then, a certain amount of NaOH solution was used to adjust the pH value to 8.5-8.7, wherein the molar ratio of formaldehyde to the second batch of urea was 0.9-0.96:0.45-0.55, and the second batch of melamine accounted for 8-12% of the mass of the formaldehyde solution. Heating was stopped and the temperature was allowed to cool to room temperature to obtain a flame retardant adhesive. (2): Preparation of flame retardant reconstituted decorative materials: (2-1) Apply the inorganic filler adhesive to the surface of the wood veneer with a certain or different thickness, with a coating amount of 110-125g / m 2 , assembling the plurality of glued veneers and then cold pressing them, with a cold pressing pressure of 0.20-0.25 MPa and a cold pressing time of 168-180 h to obtain a first group of wood squares; (2-2) Slice the first group of wood along any side into reconstructed veneers of certain or different thicknesses, and then apply flame retardant adhesive on the surface of each reconstructed veneer with a coating amount of 110-125g / m 2 , assembling the plurality of veneers after gluing and then cold pressing them, the cold pressing pressure is 0.20-0.25MPa, the cold pressing time is 168-180h, and the second group of wood squares is obtained; (2-3) The second set of wood is sliced ​​along any side into 0.40-0.60 mm thick veneers to obtain flame retardant reconstituted decorative materials.

2. The preparation method according to claim 1, wherein In the above (1-1), the average particle size of the nano-montmorillonite is 50-70 nm, and the average particle size of the nano-hydrotalcite is 50-70 nm.

3. The preparation method according to claim 1, wherein In the above (2-1), the wood veneer is any one of poplar, eucalyptus, pine or a combination thereof with a thickness of 1.7-1.8 mm and a moisture content of 8-10%.

4. The preparation method according to claim 3, wherein In the above (2-1), the glued wood veneers are assembled into blanks with a thickness of 1.2-1.5m.

5. The preparation method according to claim 4, wherein In the above (2-2), the first group of wood blocks are sliced ​​into reconstituted veneers with a thickness of 1.0-1.2 mm.

6. The preparation method according to claim 5, wherein In the above (2-2), the glue-coated reconstituted veneer is assembled into a thickness of 1.2-1.5m.

7. The preparation method according to claim 1, wherein In (2-1), the blanks are assembled along the direction of the wood grain. In the above-mentioned (2-2), the blanks are assembled along the layer direction.

8. The preparation method according to claim 7, wherein The (2-3) is sliced ​​along the side of the grid.

9. A flame retardant reconstituted decorative material, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 8.