Preparation method of flame-retardant decorative technical wood

Abstract

This invention relates to the field of decorative materials and discloses a method for preparing flame-retardant decorative engineered wood. In this method, soybean meal adhesive is used as a salt inhibitor in magnesium sulfate adhesive. After the soybean protein in the soybean meal adhesive is stretched, it can expose active groups. These active groups can form a complexation reaction with magnesium ions, thereby fixing the free magnesium ions in the adhesive layer and inhibiting their dissolution. This inhibits the efflorescence effect of magnesium sulfate-magnesium oxide flame-promoting engineered wood. Soybean meal adhesive can also improve the transverse elastic modulus of engineered wood and increase the side toughness of engineered wood, making it less prone to edge chipping during manufacturing.

Description

Technical Field

[0001] This invention relates to the field of decorative panels, and in particular to a method for preparing flame-retardant decorative engineered wood. Background Technology

[0002] Flame-retardant decorative engineered wood is a type of engineered wood product with flame-retardant properties. It is made by bonding wood fibers together using flame-retardant adhesives. Among them, magnesium oxysulfate flame-retardant engineered wood is an environmentally friendly engineered wood product with excellent flame-retardant properties and is formaldehyde-free. Magnesium oxysulfate flame-retardant engineered wood uses magnesium oxysulfate adhesive to bond and composite wood fibers. After bonding, the magnesium oxysulfate adhesive undergoes hydration to form pentahydrate magnesium oxysulfate crystals. These pentahydrate magnesium oxysulfate crystals are tobermorite needle-like crystals. These crystals can penetrate into the wood fibers and form a rigid mechanical interlocking structure with the wood fibers, thereby fixing their shape.

[0003] Magnesium oxysulfate flame-retardant engineered wood may experience efflorescence during use. When engineered wood absorbs water, soluble magnesium salts from the pentahydrate magnesium oxysulfate crystals dissolve, leading to whitening, efflorescence, and reduced bonding strength in the engineered wood. Current technologies primarily employ salt inhibitors to suppress efflorescence in magnesium oxysulfate flame-retardant engineered wood. For example, publication CN115180917A uses phosphates, which form insoluble magnesium ammonium phosphate hydrates with free magnesium ions, inhibiting the dissolution of soluble magnesium salts. Another example is publication CN110183178A, which uses additives and modified microspheres. The additive is potassium tetratitanate containing anions, which adsorbs free metal ions. The anions exchange with the adsorbed metal ions, and the modified microspheres produce calcium carbonate, densifying the structure and further inhibiting the dissolution of free metal ions. Currently, the salt inhibitors used in existing technologies are expensive, and their use increases the rigidity of engineered wood. This makes engineered wood prone to edge chipping during processing, affecting its processing performance. Therefore, it is of great significance to provide a sulfur-oxygen-magnesium flame-retardant engineered wood that is highly resilient and less prone to frost formation. Summary of the Invention

[0004] This invention provides a method for preparing flame-retardant decorative engineered wood. In this method, soybean meal gum is used as a salt inhibitor in magnesium oxysulfate adhesive. After the soybean protein in the soybean meal gum is stretched, it can expose active groups. These active groups can form complexes with magnesium ions, thereby fixing the free magnesium ions in the adhesive layer and inhibiting their dissolution. This inhibits the efflorescence and blooming of magnesium oxysulfate-assisted engineered wood. Soybean meal gum can also improve the elastic modulus of engineered wood and increase the lateral toughness of engineered wood, making it less prone to edge chipping during processing.

[0005] The specific technical solution of this invention is as follows: A method for preparing flame-retardant decorative engineered wood includes the following steps: (1) Prepare magnesium sulfate adhesive by mixing lightly calcined magnesium oxide, magnesium sulfate, retarder and water; (2) Soybean meal powder, penetrant, crosslinking agent and water are mixed to make soybean meal adhesive. Sodium hydroxide solution with a mass fraction of 0.1~1% is added to soybean meal adhesive and reacted at 20~50 ℃ to make modified soybean meal adhesive. The mass ratio of sodium hydroxide solution to soybean meal adhesive is 1:20~100. (3) The modified soybean meal gum and magnesium oxysulfate adhesive are mixed to prepare the modified magnesium oxysulfate adhesive. The mass ratio of magnesium oxysulfate adhesive to modified soybean meal gum is 1:0.2~0.4. (4) The modified magnesium oxysulfate adhesive is coated on the engineered wood veneer and then composite processed to produce flame-retardant decorative engineered wood.

[0006] As a preferred embodiment, by mass fractions, the light-burned magnesium oxide comprises 20-32 parts, magnesium sulfate heptahydrate comprises 12-20 parts, retarder comprises 0.05-0.2 parts, and water comprises 28-40 parts.

[0007] Preferably, the magnesium oxide content in lightly calcined magnesium oxide is 80-90%.

[0008] As a preferred embodiment, by weight, the soybean meal powder is 15-25 parts, the penetrant is 0.01-0.03 parts, the crosslinking agent is 0.2-0.8 parts, and the water is 15-25 parts.

[0009] Preferably, the penetrant includes one of sodium dodecyl sulfate, sodium dodecyl sulfonate, and sodium dodecylbenzene sulfonate.

[0010] Preferably, the crosslinking agent is hexamethylene diisocyanate.

[0011] As a preferred option, flame-retardant decorative engineered wood comprises, from bottom to top, a bottom balancing layer, a lower penetration layer, a wood layer, an upper penetration layer, a color base layer, a color expression layer, and a wear-resistant texture layer.

[0012] As a preferred option, the wood layer is made of engineered wood veneer and modified magnesium oxysulfate adhesive.

[0013] Preferably, the raw materials for the wood layer include one or more of radiata pine, camphor, poplar, eucalyptus, and fir.

[0014] Preferably, the bottom balancing layer includes one or more of kraft paper, non-woven fabric, melamine paper, and PVC film.

[0015] This invention provides a method for preparing flame-retardant decorative engineered wood. This method uses a magnesium oxysulfate adhesive to composite the engineered wood, resulting in engineered wood with excellent flame-retardant properties. To address the problem of efflorescence and blooming after water absorption in magnesium oxysulfate flame-retardant engineered wood, this invention modifies the magnesium oxysulfate adhesive. This invention uses soybean meal gum as a salt-inhibiting agent in the magnesium oxysulfate adhesive. The active groups in the soybean protein of the soybean meal gum can complex with free magnesium ions, thereby inhibiting the dissolution of magnesium ions and significantly suppressing the efflorescence problem of the magnesium oxysulfate adhesive.

[0016] Furthermore, soybean meal gum and magnesium oxysulfate adhesive can produce a synergistic effect. When used, the needle-like crystals of magnesium oxysulfate adhesive after hydration can penetrate the cell structure of wood fibers, while soybean meal gum can penetrate into the interior of wood fibers by penetrating the crystal structure of wood fibers, thereby strengthening the mechanical interlocking structure between wood fibers and significantly improving the bonding strength of the adhesive. In addition, the addition of soybean meal gum significantly increases the elastic modulus and toughness of engineered wood, and can significantly suppress the problem of easy edge chipping during the processing of magnesium oxysulfate flame-retardant engineered wood.

[0017] This invention also found that when only soybean meal gum is used to modify magnesium oxysulfate adhesive, engineered wood still exhibits a slight efflorescence problem after prolonged use. Therefore, in order to prolong the effect of soybean meal gum on the efflorescence problem of magnesium oxysulfate engineered wood, this invention further modified the soybean meal gum. This invention found that by slightly hydrolyzing the soybean meal gum without affecting its bonding performance, slight hydrolysis can hydrolyze soybean protein to generate L-amino acid complexes. The amino and carboxyl groups of the L-amino acid complexes can provide complexation sites for free magnesium ions, thereby significantly improving the complexation effect of soybean meal gum on magnesium ions. Therefore, this invention uses a certain concentration of sodium hydroxide to slightly hydrolyze the soybean meal gum, significantly enhancing the salt barrier properties of the soybean meal gum.

[0018] Compared with the prior art, this application has the following technical effects: (1) Soybean meal gum is used as a salt inhibitor for magnesium sulfate adhesive. The active groups of soybean protein in soybean meal gum can complex with free magnesium ions, which can significantly inhibit the efflorescence problem of magnesium sulfate engineered wood. (2) Soybean meal gum and magnesium oxysulfate adhesive have a synergistic effect. The needle-like crystals of magnesium oxysulfate adhesive after hydration can penetrate wood fibers to form a mechanical interlocking structure. Soybean meal gum can penetrate into wood fibers through needle-like crystals to enhance the mechanical interlocking effect of wood fibers and can significantly improve the bonding strength of the adhesive. (3) Soybean meal gum can also improve the elastic modulus of magnesium sulfate engineered wood, improve the toughness of magnesium sulfate engineered wood, and make magnesium sulfate engineered wood less prone to edge chipping during processing. (4) Soybean meal gum was slightly hydrolyzed using sodium hydroxide solution. While improving the adhesive properties of soybean meal gum, L-amino acid complex was hydrolyzed. The amino and carboxyl groups of the L-amino acid complex can provide complexation sites for free magnesium ions, which can significantly improve the salt barrier effect of soybean meal gum on magnesium oxysulfate adhesive. Detailed Implementation

[0019] The present invention will be further described below with reference to embodiments.

[0020] To better understand the content of this invention, further explanation is provided below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of this invention.

[0021] Example 1: A method for preparing flame-retardant decorative engineered wood includes the following steps: (1) Dissolve 16 parts of magnesium sulfate heptahydrate and 0.1 parts of retarder (citric acid) in 32 parts of water to make magnesium sulfate solution, and then add 28 parts of lightly calcined magnesium oxide to magnesium sulfate solution and stir evenly to make magnesium sulfate adhesive. (2) Add 20 parts of soybean meal powder, 0.02 parts of penetrant (sodium dodecyl sulfate) and 0.5 parts of crosslinking agent (hexamethylene diisocyanate) to 20 parts of water and stir evenly to make soybean meal adhesive. Add sodium hydroxide solution (mass fraction of 0.5%) to soybean meal adhesive at a mass ratio of 1:60 and stir for 30 min under a water bath at 45 ℃ to make modified soybean meal adhesive. (3) Add soybean meal gum to magnesium oxysulfate adhesive at a mass ratio of 0.3:1 and stir evenly to prepare modified magnesium oxysulfate adhesive; (4) Apply glue to the thin layer of wood veneer using a glue applicator, with a glue application rate of 200 g / m. 2 The glued thin layer of wood veneer is laid in an I-shape along the grain to form a engineered wood blank. During the laying process, the knots are removed and filled with wood veneer. The engineered wood blank is placed in a cold press and cold-pressed at 3 MPa for 5 minutes. After the pressure index stabilizes, the locking device prepared inside the cold press is fixed. Then the cold press opens the mold and the engineered wood blank is taken out. The engineered wood blank is sent to a curing room and cured at a curing temperature of 45 ℃ and a curing humidity of 50% for 72 hours until the glue inside the engineered wood blank is completely cured and the moisture content reaches less than 10%. After curing, the engineered wood blank is trimmed, the sides are brushed with adhesive paint, and the engineered wood blank is planed using a planer to form wood layers. (5) Apply the penetrant to the upper and lower surfaces of the wood layer to form an upper and lower penetrant layer. Then print the color base layer on the upper penetrant layer, then print the color expression layer on the color base layer, then combine the bottom balance layer with the lower penetrant layer, then combine the wear-resistant texture layer with the color expression layer, use a textured steel plate to press out a deep texture area on the wear-resistant texture layer, and then brush paint on both sides of the wood layer to form flame-retardant decorative engineered wood.

[0022] Example 2: A method for preparing flame-retardant decorative engineered wood includes the following steps: (1) Dissolve 12 parts of magnesium sulfate heptahydrate and 0.05 parts of retarder (citric acid) in 28 parts of water to make a magnesium sulfate solution, and then add 20 parts of lightly calcined magnesium oxide to the magnesium sulfate solution and stir evenly to make magnesium sulfate adhesive. (2) Add 15 parts of soybean meal powder, 0.01 parts of penetrant (sodium dodecyl sulfate) and 0.2 parts of crosslinking agent (hexamethylene diisocyanate) to 15 parts of water and stir evenly to make soybean meal adhesive. Add sodium hydroxide solution (mass fraction of 0.1%) to soybean meal adhesive at a mass ratio of 1:20 and stir for 30 min under 40 ℃ water bath conditions to make modified soybean meal adhesive; (3) Add soybean meal gum to magnesium oxysulfate adhesive at a mass ratio of 0.2:1 and stir evenly to prepare modified magnesium oxysulfate adhesive; (4) Apply glue to the thin layer of wood veneer using a glue applicator, with a glue application rate of 200 g / m. 2 The glued thin layer of wood veneer is laid in an I-shape along the grain to form a engineered wood blank. During the laying process, the knots are removed and filled with wood veneer. The engineered wood blank is placed in a cold press and cold-pressed at 3 MPa for 5 minutes. After the pressure index stabilizes, the locking device prepared inside the cold press is fixed. Then the cold press opens the mold and the engineered wood blank is taken out. The engineered wood blank is sent to a curing room and cured at a curing temperature of 45 ℃ and a curing humidity of 50% for 72 hours until the glue inside the engineered wood blank is completely cured and the moisture content reaches less than 10%. After curing, the engineered wood blank is trimmed, the sides are brushed with adhesive paint, and the engineered wood blank is planed using a planer to form wood layers. (5) Apply the penetrant to the upper and lower surfaces of the wood layer to form an upper and lower penetrant layer. Then print the color base layer on the upper penetrant layer, then print the color expression layer on the color base layer, then combine the bottom balance layer with the lower penetrant layer, then combine the wear-resistant texture layer with the color expression layer, use a textured steel plate to press out a deep texture area on the wear-resistant texture layer, and then brush paint on both sides of the wood layer to form flame-retardant decorative engineered wood.

[0023] Example 3: A method for preparing flame-retardant decorative engineered wood includes the following steps: (1) Dissolve 20 parts of magnesium sulfate heptahydrate and 0.2 parts of retarder (citric acid) in 40 parts of water to make magnesium sulfate solution, and then add 32 parts of lightly calcined magnesium oxide to magnesium sulfate solution and stir evenly to make magnesium sulfate adhesive. (2) Add 25 parts of soybean meal powder, 0.03 parts of penetrant (sodium dodecyl sulfate) and 0.8 parts of crosslinking agent (hexamethylene diisocyanate) to 25 parts of water and stir evenly to make soybean meal adhesive. Add sodium hydroxide solution (mass fraction of 1%) to soybean meal adhesive at a mass ratio of 1:100 and stir for 30 min under 50 ℃ water bath conditions to make modified soybean meal adhesive; (3) Add soybean meal gum to magnesium oxysulfate adhesive at a mass ratio of 0.2~0.4:1 and stir evenly to prepare modified magnesium oxysulfate adhesive; (4) Apply glue to the thin layer of wood veneer using a glue applicator, with a glue application rate of 200 g / m. 2 The glued thin layer of wood veneer is laid in an I-shape along the grain to form a engineered wood blank. During the laying process, the knots are removed and filled with wood veneer. The engineered wood blank is placed in a cold press and cold-pressed at 3 MPa for 5 minutes. After the pressure index stabilizes, the locking device prepared inside the cold press is fixed. Then the cold press opens the mold and the engineered wood blank is taken out. The engineered wood blank is sent to a curing room and cured at a curing temperature of 45 ℃ and a curing humidity of 50% for 72 hours until the glue inside the engineered wood blank is completely cured and the moisture content reaches less than 10%. After curing, the engineered wood blank is trimmed, the sides are brushed with adhesive paint, and the engineered wood blank is planed using a planer to form wood layers. (5) Apply the penetrant to the upper and lower surfaces of the wood layer to form an upper and lower penetrant layer. Then print the color base layer on the upper penetrant layer, then print the color expression layer on the color base layer, then combine the bottom balance layer with the lower penetrant layer, then combine the wear-resistant texture layer with the color expression layer, use a textured steel plate to press out a deep texture area on the wear-resistant texture layer, and then brush paint on both sides of the wood layer to form flame-retardant decorative engineered wood.

[0024] Example 4: A method for preparing flame-retardant decorative engineered wood includes the following steps: (1) Dissolve 16 parts of magnesium sulfate heptahydrate and 0.1 parts of retarder (citric acid) in 32 parts of water to make magnesium sulfate solution, and then add 28 parts of lightly calcined magnesium oxide to magnesium sulfate solution and stir evenly to make magnesium sulfate adhesive. (2) Add 20 parts of soybean meal powder, 0.02 parts of penetrant (sodium dodecyl sulfonate) and 0.5 parts of crosslinking agent (hexamethylene diisocyanate) to 20 parts of water and stir evenly to make soybean meal adhesive. Add sodium hydroxide solution (mass fraction of 0.5%) to soybean meal adhesive at a mass ratio of 1:60 and stir for 30 min under a water bath at 45 ℃ to make modified soybean meal adhesive. (3) Add soybean meal gum to magnesium oxysulfate adhesive at a mass ratio of 0.3:1 and stir evenly to prepare modified magnesium oxysulfate adhesive; (4) Apply glue to the thin layer of wood veneer using a glue applicator, with a glue application rate of 200 g / m. 2 The glued thin layer of wood veneer is laid in an I-shape along the grain to form a engineered wood blank. During the laying process, the knots are removed and filled with wood veneer. The engineered wood blank is placed in a cold press and cold-pressed at 3 MPa for 5 minutes. After the pressure index stabilizes, the locking device prepared inside the cold press is fixed. Then the cold press opens the mold and the engineered wood blank is taken out. The engineered wood blank is sent to a curing room and cured at a curing temperature of 45 ℃ and a curing humidity of 50% for 72 hours until the glue inside the engineered wood blank is completely cured and the moisture content reaches less than 10%. After curing, the engineered wood blank is trimmed, the sides are brushed with adhesive paint, and the engineered wood blank is planed using a planer to form wood layers. (5) Apply the penetrant to the upper and lower surfaces of the wood layer to form an upper and lower penetrant layer. Then print the color base layer on the upper penetrant layer, then print the color expression layer on the color base layer, then combine the bottom balance layer with the lower penetrant layer, then combine the wear-resistant texture layer with the color expression layer, use a textured steel plate to press out a deep texture area on the wear-resistant texture layer, and then brush paint on both sides of the wood layer to form flame-retardant decorative engineered wood.

[0025] Example 5: A method for preparing flame-retardant decorative engineered wood includes the following steps: (1) Dissolve 16 parts of magnesium sulfate heptahydrate and 0.1 parts of retarder (citric acid) in 32 parts of water to make magnesium sulfate solution, and then add 28 parts of lightly calcined magnesium oxide to magnesium sulfate solution and stir evenly to make magnesium sulfate adhesive. (2) Add 20 parts of soybean meal powder, 0.02 parts of penetrant (sodium dodecylbenzene sulfonate) and 0.5 parts of crosslinking agent (hexamethylene diisocyanate) to 20 parts of water and stir evenly to make soybean meal adhesive. Add sodium hydroxide solution (mass fraction of 0.5%) to soybean meal adhesive at a mass ratio of 1:60 and stir for 30 min under a water bath at 45 ℃ to make modified soybean meal adhesive. (3) Add soybean meal gum to magnesium oxysulfate adhesive at a mass ratio of 0.3:1 and stir evenly to prepare modified magnesium oxysulfate adhesive; (4) Apply glue to the thin layer of wood veneer using a glue applicator, with a glue application rate of 200 g / m. 2 The glued thin layer of wood veneer is laid in an I-shape along the grain to form a engineered wood blank. During the laying process, the knots are removed and filled with wood veneer. The engineered wood blank is placed in a cold press and cold-pressed at 3 MPa for 5 minutes. After the pressure index stabilizes, the locking device prepared inside the cold press is fixed. Then the cold press opens the mold and the engineered wood blank is taken out. The engineered wood blank is sent to a curing room and cured at a curing temperature of 45 ℃ and a curing humidity of 50% for 72 hours until the glue inside the engineered wood blank is completely cured and the moisture content reaches less than 10%. After curing, the engineered wood blank is trimmed, the sides are brushed with adhesive paint, and the engineered wood blank is planed using a planer to form wood layers. (5) Apply the penetrant to the upper and lower surfaces of the wood layer to form an upper and lower penetrant layer. Then print the color base layer on the upper penetrant layer, then print the color expression layer on the color base layer, then combine the bottom balance layer with the lower penetrant layer, then combine the wear-resistant texture layer with the color expression layer, use a textured steel plate to press out a deep texture area on the wear-resistant texture layer, and then brush paint on both sides of the wood layer to form flame-retardant decorative engineered wood.

[0026] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that soybean meal gum was not added to the magnesium oxysulfate adhesive; the steps include: (1) Dissolve 16 parts of magnesium sulfate heptahydrate and 0.1 parts of retarder (citric acid) in 32 parts of water to make magnesium sulfate solution, and then add 28 parts of lightly calcined magnesium oxide to magnesium sulfate solution and stir evenly to make magnesium sulfate adhesive. (2) Apply glue to the thin layer of wood veneer using a glue applicator, with a glue application rate of 200 g / m. 2 The glued thin layer of wood veneer is laid in an I-shape along the grain to form a engineered wood blank. During the laying process, the knots are removed and filled with wood veneer. The engineered wood blank is placed in a cold press and cold-pressed at 3 MPa for 5 minutes. After the pressure index stabilizes, the locking device prepared inside the cold press is fixed. Then the cold press opens the mold and the engineered wood blank is taken out. The engineered wood blank is sent to a curing room and cured at a curing temperature of 45 ℃ and a curing humidity of 50% for 72 hours until the glue inside the engineered wood blank is completely cured and the moisture content reaches less than 10%. After curing, the engineered wood blank is trimmed, the sides are brushed with adhesive paint, and the engineered wood blank is planed using a planer to form wood layers. (3) Apply the penetrant to the upper and lower surfaces of the wood layer to form an upper and lower penetrant layer. Then print the color base layer on the upper penetrant layer, then print the color expression layer on the color base layer, then combine the bottom balance layer with the lower penetrant layer, then combine the wear-resistant texture layer with the color expression layer, use a textured steel plate to press out a deep texture area on the wear-resistant texture layer, and then brush paint on both sides of the wood layer to form flame-retardant decorative engineered wood.

[0027] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that the soybean meal gum was treated with sodium hydroxide; the process included the following steps: (1) Dissolve 16 parts of magnesium sulfate heptahydrate and 0.1 parts of retarder (citric acid) in 32 parts of water to make magnesium sulfate solution, and then add 28 parts of lightly calcined magnesium oxide to magnesium sulfate solution and stir evenly to make magnesium sulfate adhesive. (2) Add 20 parts soybean meal powder, 0.02 parts penetrant (sodium dodecyl sulfate) and 0.5 parts crosslinking agent (hexamethylene diisocyanate) to 20 parts water and stir evenly to make soybean meal gum; (3) Add soybean meal gum to magnesium oxysulfate adhesive at a mass ratio of 0.3:1 and stir evenly to prepare modified magnesium oxysulfate adhesive; (4) Apply glue to the thin layer of wood veneer using a glue applicator, with a glue application rate of 200 g / m. 2 The glued thin layer of wood veneer is laid in an I-shape along the grain to form a engineered wood blank. During the laying process, the knots are removed and filled with wood veneer. The engineered wood blank is placed in a cold press and cold-pressed at 3 MPa for 5 minutes. After the pressure index stabilizes, the locking device prepared inside the cold press is fixed. Then the cold press opens the mold and the engineered wood blank is taken out. The engineered wood blank is sent to a curing room and cured at a curing temperature of 45 ℃ and a curing humidity of 50% for 72 hours until the glue inside the engineered wood blank is completely cured and the moisture content reaches less than 10%. After curing, the engineered wood blank is trimmed, the sides are brushed with adhesive paint, and the engineered wood blank is planed using a planer to form wood layers. (5) Apply the penetrant to the upper and lower surfaces of the wood layer to form an upper and lower penetrant layer. Then print the color base layer on the upper penetrant layer, then print the color expression layer on the color base layer, then combine the bottom balance layer with the lower penetrant layer, then combine the wear-resistant texture layer with the color expression layer, use a textured steel plate to press out a deep texture area on the wear-resistant texture layer, and then brush paint on both sides of the wood layer to form flame-retardant decorative engineered wood.

[0028] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that the amount of soybean meal gum used was too low, and the mass ratio of soybean meal gum to magnesium oxysulfate adhesive was 0.1:1; all other conditions were the same as in Example 1.

[0029] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that the amount of soybean meal gum used was too high, and the mass ratio of soybean meal gum to magnesium oxysulfate adhesive was 0.6:1; all other conditions were the same as in Example 1.

[0030] Comparative Example 5: The difference between Comparative Example 5 and Example 1 is that the sodium hydroxide solution was over-hydrolyzed, and 5% sodium hydroxide was used to hydrolyze soybean meal gum at 40°C for 30 min; all other conditions were the same as in Example 1.

[0031] Comparative Example 6: The difference between Comparative Example 6 and Example 1 is that the sodium hydroxide solution was insufficient for hydrolysis, and 0.05% sodium hydroxide was used to hydrolyze soybean meal gum at 25°C for 10 min; all other conditions were the same as in Example 1.

[0032] Example of detection: The physical and chemical properties and efflorescence properties of the flame-retardant decorative engineered wood of Examples 1-5 and Comparative Examples 1-6 were tested. The physical and chemical performance tests include: static bending strength, modulus of elasticity, and internal bond strength. The test methods are in accordance with GB / T17657-2022 "Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels". The test method for efflorescence performance refers to "T / CECS 10397—2024 Sulfur-oxygen-magnesium-based cementitious materials". The flame-retardant decorative engineered wood is placed upright in a constant temperature and humidity chamber with a relative humidity of 90% and a temperature of 40℃. The salt precipitation area ratio of the upper and lower surfaces and four sides of the specimen is observed at 3d, 15d and 30d respectively. The test results are shown in Table 1; Table 1. Results of Physicochemical Performance Tests As shown in Table 1, the static bending strength of the flame-retardant decorative engineered wood prepared in Examples 1 to 5 was 11–13 MPa, the elastic modulus was 1478–1582 MPa, and the internal bond strength was 1–1.1 MPa. In Comparative Example 1, the magnesium oxysulfate adhesive was not modified, and its static bending strength was 9 MPa, the elastic modulus was 783 MPa, and the internal bond strength was 0.7 MPa. Compared with Comparative Example 1, Example 1 showed significantly improved static bending strength, elastic modulus, and internal bond strength, indicating that modifying the magnesium oxysulfate adhesive with soybean meal adhesive can significantly improve the rigidity, toughness, and bonding strength of the magnesium oxysulfate flame-retardant engineered wood. The amount of soybean meal adhesive used in Comparative Examples 3 and 4 was investigated. The results showed that when the amount of soybean meal adhesive was too small, the static bending strength, elastic modulus, and bonding strength of the magnesium oxysulfate flame-retardant engineered wood were all lower than those in the Examples. When the amount of soybean meal adhesive was too high, the bonding strength and modulus of elasticity of the magnesium oxysulfate flame-retardant engineered wood did not change significantly. However, compared with the example, the static bending strength of the magnesium oxysulfate flame-retardant engineered wood was significantly reduced, which indicates that excessive soybean meal adhesive will reduce the rigidity of the flame-retardant engineered wood.

[0033] Analysis of the efflorescence performance of engineered wood revealed that the engineered wood prepared in the examples exhibited slight salt precipitation after 30 days in a humid environment. The engineered wood prepared in Comparative Example 1 showed slight salt precipitation after 5 days, with the salt precipitation area reaching 34% after 30 days, indicating severe efflorescence and blooming. The engineered wood prepared in Comparative Example 2 showed slight salt precipitation after 15 days, with the salt precipitation intensifying after 30 days. The results from the examples, Comparative Example 1, and Comparative Example 2 indicate that soybean meal gum can significantly inhibit the efflorescence and blooming of magnesium oxysulfate adhesives. Soybean meal gum modified with sodium hydroxide solution further enhances its inhibitory effect on magnesium oxysulfate adhesives. Comparative Examples 5 and 6 illustrate the effect of the degree of hydrolysis on the properties of soybean meal gum. The results show that while a lower degree of hydrolysis can enhance the inhibition of efflorescence and blooming of magnesium oxysulfate adhesives, the effect is not significant, while excessive hydrolysis leads to a decrease in the physicochemical properties of the engineered wood.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing flame-retardant decorative engineered wood, characterized in that, Includes the following steps: (1) Prepare magnesium sulfate adhesive by mixing lightly calcined magnesium oxide, magnesium sulfate, retarder and water; (2) Soybean meal powder, penetrant, crosslinking agent and water are mixed to make soybean meal adhesive. Sodium hydroxide solution with a mass fraction of 0.1~1% is added to soybean meal adhesive and reacted at 40~50 ℃ to make modified soybean meal adhesive. The mass ratio of sodium hydroxide solution to soybean meal adhesive is 1:20~100. (3) The modified soybean meal gum and magnesium oxysulfate adhesive are mixed to prepare the modified magnesium oxysulfate adhesive. The mass ratio of magnesium oxysulfate adhesive to modified soybean meal gum is 1:0.2~0.

4. (4) The modified magnesium oxysulfate adhesive is coated on the engineered wood veneer and then composite processed to produce flame-retardant decorative engineered wood.

2. The preparation method according to claim 1, characterized in that, By mass fraction, the light-burned magnesium oxide is 20-32 parts, magnesium sulfate heptahydrate is 12-20 parts, retarder is 0.05-0.2 parts, and water is 28-40 parts.

3. The preparation method according to claim 1 or 2, characterized in that, The magnesium oxide content in lightly calcined magnesium oxide is 80-90%.

4. The preparation method according to claim 1, characterized in that, By weight, the soybean meal powder is 15-25 parts, the penetrant is 0.01-0.03 parts, the cross-linking agent is 0.2-0.8 parts, and the water is 15-25 parts.

5. The preparation method according to claim 3, characterized in that, The penetrant includes one of sodium dodecyl sulfate, sodium dodecyl sulfonate, and sodium dodecylbenzene sulfonate.

6. The preparation method according to claim 3, characterized in that, The crosslinking agent is hexamethylene diisocyanate.

7. The preparation method according to claim 1, characterized in that it is flame retardant. Decorative engineered wood, from bottom to top, includes a bottom balancing layer, a lower penetration layer, a wood layer, an upper penetration layer, a color base layer, a color expression layer, and a wear-resistant texture layer.

8. The preparation method according to claim 7, characterized in that, The wood layer is made of engineered wood veneer and modified magnesium oxysulfate adhesive.

9. The preparation method according to claim 7 or 8, characterized in that, The raw materials for the wood layer include one or more of radiata pine, camphor, poplar, eucalyptus, and fir.

10. The preparation method according to claim 7, characterized in that, The bottom balancing layer includes one or more of kraft paper, non-woven fabric, melamine paper, and PVC film.

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