Low water absorption anti-cracking inorganic artificial board and preparation method thereof

Abstract

This invention relates to the field of engineered wood products technology, and discloses a low-absorption, crack-resistant inorganic engineered wood product and its preparation method. The raw materials of the engineered wood product include a substrate, inorganic mineral powder, and a modified adhesive. The modified adhesive includes a gel-type adhesive and a modifier. By mass, the modifier includes: 40-50 parts of difluoromethoxyacrylate emulsion, 0.2-0.5 parts of basalt fiber, 0.2-0.4 parts of silane coupling agent, and additives. The method uses difluoromethoxyacrylate emulsion, basalt fiber, and silane coupling agent to prepare the modifier. The difluoromethoxyacrylate emulsion particles can be adsorbed on the surface of the basalt fiber. During the gradual curing process after the modifier and adhesive are mixed, the difluoromethoxyacrylate emulsion will dehydrate and break down, interpenetrating between the gel adhesive, basalt, substrate, and inorganic particles, significantly reducing the shrinkage rate of the board.

Description

Technical Field

[0001] This invention relates to the field of engineered wood products technology, and in particular to a low-water-absorption, crack-resistant inorganic engineered wood product and its preparation method. Background Technology

[0002] Traditional fiberboard is mainly made by hot pressing plant fibers with thermosetting adhesives. However, the hot pressing process has problems such as high energy consumption and deterioration of board performance. At the same time, thermosetting adhesives also have the problem of excessive formaldehyde release. Therefore, in order to reduce and solve the above problems, those skilled in the art have proposed a technical solution of cold-pressed fiberboard.

[0003] The adhesives used in cold-pressed fiberboard mainly employ inorganic gel-type adhesives. For example, CN108818877A discloses a method and system for cold-pressing plant fiberboard and a cold-pressing adhesive, which uses magnesium oxysulfate adhesive to prepare the cold-pressed fiberboard. Another example is CN102531492B, which discloses a cement-based wood fiberboard and its preparation method, using silicate cement as an adhesive to prepare the cold-pressed fiberboard. After researching cold-pressed fiberboard, this invention found that its waterproof and crack-resistant properties are relatively low, failing to meet the requirements for mid-to-high-end performance. Therefore, further optimization of the preparation process of cold-pressed fiberboard is needed to ensure that its static bending strength, waterproof performance, and crack resistance meet the requirements. Summary of the Invention

[0004] The purpose of this invention is to improve the waterproof and crack-resistant properties of fiberboard.

[0005] This invention uses a modified adhesive containing a modifier to prepare fiber-reinforced engineered wood panels. The modifier includes difluoromethoxyacrylate, basalt fiber, emulsifier, and other additives. The modifier can significantly improve the waterproof and crack-resistant properties of the fiber-reinforced engineered wood panels.

[0006] The modifier of this invention is made using an emulsification process, which can reduce the shrinkage rate of the board.

[0007] The specific technical solution of this invention is as follows: A low-water-absorption, crack-resistant inorganic engineered wood panel, comprising a substrate, inorganic mineral powder, and a modified adhesive; the modified adhesive comprises a gel-type adhesive and a modifier, wherein the modifier comprises, by weight, 40-50 parts of difluoromethoxyacrylate emulsion, 0.2-0.5 parts of basalt fiber, 0.2-0.4 parts of silane coupling agent, and additives.

[0008] Preferably, the additives include dispersants and pH stabilizers, and the silane coupling agent is one of aminosilane, acryloyloxysilane, epoxysilane and mercaptosilane.

[0009] Preferably, the substrate includes one or both of straw and wood chips, and the inorganic mineral powder includes one or both of quartz sand and talc powder.

[0010] Preferably, the raw materials for gel-type adhesives include a variety of sodium hydroxide, potassium hydroxide, ultrafine sodium silicate, potassium silicate, calcium sulfate, calcium carbonate, magnesium oxide, magnesium sulfate, silicon dioxide, slag, and fly ash.

[0011] A method for preparing the above-mentioned low water absorption and crack-resistant inorganic artificial board includes the following steps: (1) Disperse basalt fibers in water to make a fiber suspension; (2) The difluoromethoxyacrylate emulsion, fiber suspension, silane coupling agent and additives are modified, and after the modification is completed, the mixture is cooled, cured and filtered to produce the modifier. (3) Mix gel-type adhesive with modifier to make modified adhesive, then make adhesive material by combining substrate, inorganic mineral powder and modified adhesive, and then press the adhesive material into low water absorption and crack-resistant inorganic artificial board.

[0012] Preferably, the modification treatment conditions include: temperature 35~45 ℃ and rotation speed 800~5000 rpm.

[0013] Preferably, the modification treatment conditions include: adding the fiber suspension and silane coupling agent at a rotation speed of 3000 rpm and a pH of 7.5~8.5.

[0014] Preferably, the emulsification conditions for the difluoromethoxyacrylate emulsion include: a dropping rate of 1.5~5.0 g / min and a rotation speed of 5000~8000 rpm for adding difluoromethoxyacrylate.

[0015] Preferably, the emulsion particle size of the difluoromethoxyacrylate emulsion is 150~250 nm.

[0016] Preferably, cold pressing is used, with a pressure of 10~20 MPa.

[0017] This invention provides a low-absorption, crack-resistant inorganic engineered wood panel. This panel is made by adding inorganic mineral powder to a fiber-reinforced engineered wood panel, which enhances its mechanical properties. The panel also utilizes a modified adhesive, which is created by adding a modifier to a gel-type adhesive. The modifier incorporates difluoromethoxyacrylate and basalt fiber. Difluoromethoxyacrylate contains strongly hydrophobic fluorine groups, significantly improving the panel's water resistance, while basalt fiber enhances the mechanical properties of the gel adhesive, further improving the overall mechanical properties of the engineered wood panel.

[0018] This invention uses a modifier prepared from dimethoxyacrylate emulsion, basalt fiber, and silane coupling agent. The basalt fiber used in the modifier has a length of 3-8 μm and a fineness of 2-4 μm. The particle size of the dimethoxyacrylate emulsion is 150-250 nm. After the basalt fiber and silane coupling agent are added to the dimethoxyacrylate emulsion, the emulsion particles are adsorbed onto the surface of the basalt fiber by the silane coupling agent, so that the dimethoxyacrylate emulsion and basalt are bonded together. After the modifier is mixed with a gel-type adhesive, the dimethoxyacrylate emulsion particles in the modifier will gradually demulsify and disperse among the gel adhesive, basalt, substrate, and inorganic particles during curing and dehydration, which significantly reduces the shrinkage rate of the board. Silane coupling agents enable dimethoxyacrylate emulsion particles to be more effectively adsorbed onto basalt. Furthermore, after dehydration and curing, silane coupling agents can form bonds with dimethoxyacrylate and basalt, further enhancing the bonding performance between dimethoxyacrylate and basalt and reducing the shrinkage rate of the board.

[0019] Compared with the prior art, this application has the following technical effects: (1) This invention adds inorganic particles to fiber-reinforced engineered wood panels to increase their mechanical properties; (2) In this invention, a modified adhesive is used in fiber-reinforced engineered wood panels. The modifier in the modified adhesive is difluoromethoxyacrylate and basalt fiber. Adding difluoromethoxyacrylate can introduce highly hydrophobic fluorine, which significantly improves the water resistance of the engineered wood panels. Basalt fiber can further improve the mechanical properties of the engineered wood panels and improve their crack resistance. (3) The present invention uses dimethoxyacrylate emulsion, basalt fiber and silane coupling agent to prepare modifier. The dimethoxyacrylate emulsion particles can be adsorbed on the surface of basalt fiber. During the gradual curing process after the modifier is mixed with the adhesive, the dimethoxyacrylate emulsion will dehydrate and break the emulsion and interweave between the gel adhesive, basalt, substrate and inorganic particles, which significantly reduces the shrinkage rate of the board. Detailed Implementation

[0020] The present invention will be further described below with reference to embodiments.

[0021] 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. Example 1:

[0022] A method for preparing a low-water-absorption, crack-resistant inorganic engineered wood panel includes the following steps: (1) Add 4 parts of dispersant (ethylene glycol monobutyl ether) to deionized water and then add 0.5 parts of basalt fiber (length 3~8 μm, fineness 2~4 μm, tensile strength ≥3000 MPa, elastic modulus 80~110 GPa) and disperse at 3000 rpm for 5 min to make fiber suspension; (2) Dissolve 2.5 parts of fatty alcohol polyoxyethylene ether and 2.5 parts of sodium alkylbenzene sulfonate in deionized water to prepare an emulsifier; (3) Heat 50 parts of difluoromethoxyacrylate (purity ≥98%, molecular weight 180~200 g / mol) to 40 ℃ and keep warm for 30 min. Add the emulsifier to the reaction vessel at 40 ℃ and stir at 8000 rpm. Then slowly add the difluoromethoxyacrylate to the emulsifier at a dropping rate of 2.0 g / min. After the dropping is completed, continue emulsification for 15 min. Use a laser particle size analyzer to monitor the emulsion particle size and control the emulsion particle size within 150 nm to prepare difluoromethoxyacrylate emulsion. (4) Add the fiber suspension to the difluoromethoxyacrylate emulsion and stir at 3000 rpm for 10 min. Then add the silane coupling agent (γ-aminopropyltriethoxysilane) and continue stirring at 3000 rpm for 20 min. Then add the pH adjuster (sodium bicarbonate) to control the pH of the emulsion at 8.5. After natural cooling, let it stand for 12 h to stabilize the emulsion system. Filter the matured solution with a 200-mesh nylon filter to remove fiber agglomerates and impurities to make a modifier. (5) The modifier and gel adhesive (magnesium oxide adhesive with pH 8) are mixed at a mass ratio of 5:100 to prepare the modified adhesive; the substrate (100-mesh fine wood chips with a moisture content of 25%), the modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare the surface gel; the substrate (1-2 cm coarse wood chips and 0.5 cm straw and fine wood chips with a mass ratio of 10:90, with a moisture content of 25%), the modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare the core gel; (6) After the surface gel and core gel are laid out, they are first pre-pressed under 0.8 MPa pressure, and then cold-pressed under 20 MPa pressure to form a locking template blank. After pressure curing for 24 h, the moisture content is then cured to 10%, and the edges are ground and cut to form a low water absorption and crack-resistant inorganic artificial board. Example 2:

[0023] A method for preparing a low-water-absorption, crack-resistant inorganic engineered wood panel includes the following steps: (1) Add 3 parts of dispersant (ethylene glycol monobutyl ether) to deionized water and then add 0.3 parts of basalt fiber (length 3~8 μm, fineness 2~4 μm, tensile strength ≥3000 MPa, elastic modulus 80~110 GPa) and disperse at 3000 rpm for 5 min to make fiber suspension; (2) Dissolve 2 parts fatty alcohol polyoxyethylene ether and 2 parts sodium alkylbenzene sulfonate in deionized water to prepare an emulsifier; (3) Heat 45 parts of difluoromethoxyacrylate (purity ≥98%, molecular weight 180~200 g / mol) to 40 ℃ and keep warm for 30 min. Add the emulsifier to the reaction vessel at 40 ℃ and stir at 6500 rpm. Then slowly add the difluoromethoxyacrylate to the emulsifier at a dropping rate of 1.75 g / min. After the dropping is completed, continue emulsification for 15 min. Use a laser particle size analyzer to monitor the emulsion particle size and control the emulsion particle size within 200 nm to prepare difluoromethoxyacrylate emulsion. (4) Add the fiber suspension to the difluoromethoxyacrylate emulsion and stir at 3000 rpm for 10 min. Then add the silane coupling agent (γ-aminopropyltriethoxysilane) and continue stirring at 3000 rpm for 20 min. Then add the pH adjuster (sodium bicarbonate) to control the pH of the emulsion at 8. After natural cooling, let it stand for 12 h to stabilize the emulsion system. Filter the matured solution with a 200-mesh nylon filter to remove fiber agglomerates and impurities to make a modifier. (5) The modifier and gel adhesive (magnesium oxide adhesive with pH 8) are mixed at a mass ratio of 4:100 to prepare the modified adhesive; the substrate (100-mesh fine wood chips with a moisture content of 25%), the modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare the surface gel; the substrate (1.5 cm coarse wood chips and 0.5 cm straw and fine wood chips with a mass ratio of 10:90, with a moisture content of 25%), the modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare the core gel. (6) After the surface gel and core gel are laid out, they are first pre-pressed under 0.6 MPa pressure, and then cold-pressed under 15 MPa pressure to form a locking template blank. After pressure is maintained and cured for 24 h, the moisture content is then cured to 12% and the edges are ground and cut to form a low water absorption and crack-resistant inorganic artificial board. Example 3:

[0024] A method for preparing a low-water-absorption, crack-resistant inorganic engineered wood panel includes the following steps: (1) Add 2 parts of dispersant (ethylene glycol monobutyl ether) to deionized water and then add 0.2 parts of basalt fiber (length 3~8 μm, fineness 2~4 μm, tensile strength ≥3000 MPa, elastic modulus 80~110 GPa) and disperse at 3000 rpm for 5 min to make fiber suspension; (2) Dissolve 1.5 parts of fatty alcohol polyoxyethylene ether and 1.5 parts of sodium alkylbenzene sulfonate in deionized water to prepare an emulsifier; (3) Heat 40 parts of difluoromethoxyacrylate (purity ≥98%, molecular weight 180~200 g / mol) to 40 ℃ and keep warm for 30 min. Add the emulsifier to the reaction vessel at 40 ℃ and stir at 5000 rpm. Then slowly add the difluoromethoxyacrylate to the emulsifier at a dropping rate of 1.5 g / min. After the dropping is completed, continue emulsification for 15 min. Use a laser particle size analyzer to monitor the emulsion particle size and control the emulsion particle size within 250 nm to prepare difluoromethoxyacrylate emulsion. (4) Add the fiber suspension to the difluoromethoxyacrylate emulsion and stir at 3000 rpm for 10 min. Then add the silane coupling agent (γ-aminopropyltriethoxysilane) and continue stirring at 3000 rpm for 20 min. Then add the pH adjuster (sodium bicarbonate) to control the pH of the emulsion at 7.5. After natural cooling, let it stand for 12 h to stabilize the emulsion system. Filter the matured solution with a 200-mesh nylon filter to remove fiber agglomerates and impurities to make a modifier. (5) The modifier and gel adhesive (magnesium oxide adhesive with pH 8) are mixed at a mass ratio of 3:100 to prepare the modified adhesive; the substrate (100-mesh fine wood chips with a moisture content of 25%), the modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare the surface gel; the substrate (1-2 cm coarse wood chips and 0.5 cm straw and fine wood chips with a mass ratio of 10:90, with a moisture content of 25%), the modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare the core gel; (6) After the surface gel and core gel are laid out, they are first pre-pressed under a pressure of 0.4 MPa, and then cold-pressed under a pressure of 10 MPa to form a locking template blank. After pressure is maintained and cured for 24 h, the moisture content is then cured to 15%, and the edges are ground and cut to form a low water absorption and crack-resistant inorganic artificial board. Example 4:

[0025] A method for preparing a low-water-absorption, crack-resistant inorganic engineered wood panel includes the following steps: (1) Add 4 parts of dispersant (ethylene glycol monobutyl ether) to deionized water and then add 0.5 parts of basalt fiber (length 3~8 μm, fineness 2~4 μm, tensile strength ≥3000 MPa, elastic modulus 80~110 GPa) and disperse at 3000 rpm for 5 min to make fiber suspension; (2) Dissolve 2.5 parts of fatty alcohol polyoxyethylene ether and 2.5 parts of sodium alkylbenzene sulfonate in deionized water to prepare an emulsifier; (3) Heat 50 parts of difluoromethoxyacrylate (purity ≥98%, molecular weight 180~200 g / mol) to 40 ℃ and keep warm for 30 min. Add the emulsifier to the reaction vessel at 40 ℃ and stir at 8000 rpm. Then slowly add the difluoromethoxyacrylate to the emulsifier at a dropping rate of 2.0 g / min. After the dropping is completed, continue emulsification for 15 min. Use a laser particle size analyzer to monitor the emulsion particle size and control the emulsion particle size within 150 nm to prepare difluoromethoxyacrylate emulsion. (4) Add the fiber suspension to the difluoromethoxyacrylate emulsion and stir at 3000 rpm for 10 min. Then add the silane coupling agent (3-mercaptopropyltriethoxysilane) and continue stirring at 3000 rpm for 20 min. Then add the pH adjuster (sodium bicarbonate) to control the pH of the emulsion at 8.5. After natural cooling, let it stand for 12 h to stabilize the emulsion system. Filter the matured solution with a 200-mesh nylon filter to remove fiber agglomerates and impurities to prepare the modifier. (5) The modifier and gel adhesive (magnesium oxide adhesive with pH 8) are mixed at a mass ratio of 5:100 to prepare the modified adhesive; the substrate (100-mesh fine wood chips with a moisture content of 25%), the modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare the surface gel; the substrate (1-2 cm coarse wood chips and 0.5 cm straw and fine wood chips with a mass ratio of 10:90, with a moisture content of 25%), the modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare the core gel; (6) After the surface gel and core gel are laid out, they are first pre-pressed under 0.8 MPa pressure, and then cold-pressed under 20 MPa pressure to form a locking template blank. After pressure curing for 24 h, the moisture content is then cured to 10%, and the edges are ground and cut to form a low water absorption and crack-resistant inorganic artificial board. Example 5:

[0026] A method for preparing a low-water-absorption, crack-resistant inorganic engineered wood panel includes the following steps: (1) Add 4 parts of dispersant (ethylene glycol monobutyl ether) to deionized water and then add 0.5 parts of basalt fiber (length 3~8 μm, fineness 2~4 μm, tensile strength ≥3000 MPa, elastic modulus 80~110 GPa) and disperse at 3000 rpm for 5 min to make fiber suspension; (2) Dissolve 2.5 parts of fatty alcohol polyoxyethylene ether and 2.5 parts of sodium alkylbenzene sulfonate in deionized water to prepare an emulsifier; (3) Heat 50 parts of difluoromethoxyacrylate (purity ≥98%, molecular weight 180~200 g / mol) to 40 ℃ and keep warm for 30 min. Add the emulsifier to the reaction vessel at 40 ℃ and stir at 8000 rpm. Then slowly add the difluoromethoxyacrylate to the emulsifier at a dropping rate of 2.0 g / min. After the dropping is completed, continue emulsification for 15 min. Use a laser particle size analyzer to monitor the emulsion particle size and control the emulsion particle size within 150 nm to prepare difluoromethoxyacrylate emulsion. (4) Add the fiber suspension to the difluoromethoxyacrylate emulsion and stir at 3000 rpm for 10 min. Then add the silane coupling agent (γ-methacryloxypropyltrimethoxysilane) and continue stirring at 3000 rpm for 20 min. Then add the pH adjuster (sodium bicarbonate) to control the pH of the emulsion at 8.5. After natural cooling, let it stand for 12 h to stabilize the emulsion system. Filter the matured solution with a 200-mesh nylon filter to remove fiber agglomerates and impurities to make a modifier. (5) The modifier and gel adhesive (magnesium oxide adhesive with pH 8) are mixed at a mass ratio of 5:100 to prepare the modified adhesive; the substrate (100-mesh fine wood chips with a moisture content of 25%), the modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare the surface gel; the substrate (1-2 cm coarse wood chips and 0.5 cm straw and fine wood chips with a mass ratio of 10:90, with a moisture content of 25%), the modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare the core gel; (6) After the surface gel and core gel are laid out, they are first pre-pressed under 0.8 MPa pressure, and then cold-pressed under 20 MPa pressure to form a locking template blank. After pressure curing for 24 h, the moisture content is then cured to 10%, and the edges are ground and cut to form a low water absorption and crack-resistant inorganic artificial board. Example 6:

[0027] A method for preparing a low-water-absorption, crack-resistant inorganic engineered wood panel includes the following steps: (1) Add 4 parts of dispersant (ethylene glycol monobutyl ether) to deionized water and then add 0.5 parts of basalt fiber (length 3~8 μm, fineness 2~4 μm, tensile strength ≥3000 MPa, elastic modulus 80~110 GPa) and disperse at 3000 rpm for 5 min to make fiber suspension; (2) Dissolve 2.5 parts of fatty alcohol polyoxyethylene ether and 2.5 parts of sodium alkylbenzene sulfonate in deionized water to prepare an emulsifier; (3) Heat 50 parts of difluoromethoxyacrylate (purity ≥98%, molecular weight 180~200 g / mol) to 40 ℃ and keep warm for 30 min. Add the emulsifier to the reaction vessel at 40 ℃ and stir at 8000 rpm. Then slowly add the difluoromethoxyacrylate to the emulsifier at a dropping rate of 2.0 g / min. After the dropping is completed, continue emulsification for 15 min. Use a laser particle size analyzer to monitor the emulsion particle size and control the emulsion particle size within 150 nm to prepare difluoromethoxyacrylate emulsion. (4) Add the fiber suspension to the difluoromethoxyacrylate emulsion and stir at 3000 rpm for 10 min. Then add the silane coupling agent (γ-glycidyl etheroxypropyltrimethoxysilane) and continue stirring at 3000 rpm for 20 min. Then add the pH adjuster (sodium bicarbonate) to control the pH of the emulsion at 8.5. After natural cooling, let it stand for 12 h to stabilize the emulsion system. Filter the matured solution with a 200-mesh nylon filter to remove fiber agglomerates and impurities to make a modifier. (5) The modifier and gel adhesive (magnesium oxide adhesive with pH 8) are mixed at a mass ratio of 5:100 to prepare the modified adhesive; the substrate (100-mesh fine wood chips with a moisture content of 25%), the modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare the surface gel; the substrate (1-2 cm coarse wood chips and 0.5 cm straw and fine wood chips with a mass ratio of 10:90, with a moisture content of 25%), the modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare the core gel; (6) After the surface gel and core gel are laid out, they are first pre-pressed under 0.8 MPa pressure, and then cold-pressed under 20 MPa pressure to form a locking template blank. After pressure curing for 24 h, the moisture content is then cured to 10%, and the edges are ground and cut to form a low water absorption and crack-resistant inorganic artificial board.

[0028] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that no modifier was added, and all other conditions were the same as in Example 1.

[0029] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that no basalt fiber was added, while all other conditions were the same as in Example 1.

[0030] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that no silane coupling agent was added, while all other conditions were the same as in Example 1.

[0031] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that difluoromethoxyacrylate was not added, while all other conditions were the same as in Example 1.

[0032] Comparative Example 5: The difference between Comparative Example 5 and Example 1 is that: the basalt fiber is coated with difluoromethoxyacrylate, which includes the following steps: (1) Heat 50 parts of difluoromethoxyacrylate (purity ≥98%, molecular weight 180~200 g / mol) to 40 ℃ and keep warm for 30 min, then add 4 parts of dispersant, 0.4 parts of silane coupling agent (γ-aminopropyltriethoxysilane) and 0.5 parts of basalt fiber (length 3~8 μm, fineness 2~4 μm, tensile strength ≥3000 MPa, elastic modulus 80~110 GPa) and dry to make modified basalt fiber; (2) Modified basalt fiber and gel-type adhesive (magnesium oxide adhesive with pH 8) are mixed at a mass ratio of 5:100 to prepare modified adhesive; base material (100-mesh fine wood chips with a moisture content of 25%), modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare surface gel; base material (1-2 cm coarse wood chips and 0.5 cm straw and fine wood chips with a mass ratio of 10:90, with a moisture content of 25%), modified adhesive and inorganic mineral powder (800-mesh talc) are mixed at a mass ratio of 54:36:10 to prepare core gel; (3) After the surface gel and core gel are laid out, they are first pre-pressed under 0.8 MPa pressure, and then cold-pressed under 20 MPa pressure to form a locking template blank. After pressure curing for 24 h, the moisture content is then cured to 10% and the edges are ground and cut to form a low water absorption and crack-resistant inorganic artificial board.

[0033] Comparative Example 6: The difference between Comparative Example 6 and Example 1 is that the emulsification speed of difluoromethoxyacrylate was 10,000 rpm, while all other conditions were the same as in Example 1.

[0034] Detection Example 1: The engineered wood panels prepared in Examples 1-6 and Comparative Examples 1-6 were tested. The test items included: water absorption rate, flexural strength, crack resistance under thermal cycling at -20~60 ℃, and shrinkage rate. The water absorption rate was tested in accordance with the content published in GB / T 17657-2022 Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels 4.4 Determination of Water Absorption Thickness Swelling Rate; Bending strength was tested in accordance with the content published in GB / T 17657-2013 Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels; The test method for thermal cycling from -20 to 60 ℃ is conducted in accordance with the content disclosed in GB / T 17657-2022 Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels 4.40 Determination of Surface Resistance to Thermal Cycling. The test results are shown in Table 1; Table 1 Test Results As shown in Table 1, the water absorption rate of the artificial board prepared by the present invention can reach 0.6~0.8%, the bending strength can reach 20~29 MPa, the shrinkage rate of the board can reach 0.2~0.5%, and no cracks appear after 50 cycles of hot and cold, with a dimensional change rate of 0.15~0.21%. Compared with the artificial board without modifier in Comparative Example 1, the artificial board prepared by the present invention has significantly increased waterproof performance, bending strength and crack resistance, and significantly reduced shrinkage rate.

[0035] The results of Examples 1, 2 and 3 show that as the amount of modified adhesive increases, the water absorption rate, shrinkage rate and dimensional change rate after 50 cycles of the engineered wood product decrease, while the flexural strength increases. These results indicate that increasing the amount of modified adhesive can improve the waterproof performance, mechanical properties and crack resistance of the engineered wood product, as well as reduce the shrinkage rate, reduce the deformation, and increase the yield of the finished product.

[0036] The results of Examples 1, 4, 5, and 6 show that different silane coupling agents affect the shrinkage rate of the boards. After analysis, it was found that the amino, sulfur, and epoxy groups introduced by aminosilane, thiosilane, and epoxysilane do not form chemical bonds with difluoromethoxyacrylate, while the group introduced by acryloyloxysilane can form chemical bonds with difluoromethoxyacrylate, which can further improve the bonding force between difluoromethoxyacrylate and basalt fiber, thereby further reducing the shrinkage performance of the wood-based panels.

[0037] Comparative Example 2 represents a technical solution without basalt fiber, Comparative Example 3 represents a technical solution without silane coupling agent, and Comparative Example 4 represents a technical solution without difluoromethoxyacrylate. The results showed that, compared to Example 1, Comparative Examples 2, 3, and 4 exhibited significantly increased shrinkage and 50-cycle dimensional change rates in the engineered wood panels. This indicates a synergistic effect between basalt fiber, silane coupling agent, and difluoromethoxyacrylate; their combined use can reduce volumetric changes and improve dimensional stability.

[0038] Comparative Example 5 illustrates a technical solution using difluoromethoxyacrylate to coat basalt fibers. The results showed that when difluoromethoxyacrylate was used as a modifier for basalt fibers, the shrinkage rate and dimensional change rate after thermal cycling of the engineered wood product were still significantly lower than those of the engineered wood product using the difluoromethoxyacrylate-basalt fiber emulsion system. Analysis revealed that the difluoromethoxyacrylate coating on the basalt fibers only introduces hydrophobic groups and does not interact with the basalt fibers, adhesives, or matrix. However, with the emulsion system, the emulsion particles gradually disperse and interweave between the adhesive, basalt fibers, and matrix during subsequent curing and dehydration, forming an interwoven network. This prevents the board from easily deforming, significantly improving the dimensional stability of the board and significantly reducing the shrinkage rate.

[0039] 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 low-water-absorption, crack-resistant inorganic engineered wood panel, characterized in that, The raw materials include a base material, inorganic mineral powder, and modified adhesive; the raw materials of the modified adhesive include a gel-type adhesive and a modifier. The raw materials of the modifier, by mass, include: 40-50 parts of difluoromethoxyacrylate emulsion, 0.2-0.5 parts of basalt fiber, 0.2-0.4 parts of silane coupling agent, and additives.

2. The low water absorption, crack-resistant inorganic engineered wood panel according to claim 1, characterized in that, The additives include dispersants and pH stabilizers, and the silane coupling agent is one of aminosilane, acryloyloxysilane, epoxysilane and mercaptosilane.

3. The low water absorption, crack-resistant inorganic engineered wood panel according to claim 1, characterized in that, The substrate includes one or both of straw and wood chips, and the inorganic mineral powder includes one or both of quartz sand and talc powder.

4. The low water absorption, crack-resistant inorganic engineered wood panel according to claim 1, characterized in that, The raw materials for gel-type adhesives include various types of sodium hydroxide, potassium hydroxide, ultrafine sodium silicate, potassium silicate, calcium sulfate, calcium carbonate, magnesium oxide, magnesium sulfate, silicon dioxide, slag, and fly ash.

5. A method for preparing a low-water-absorption, crack-resistant inorganic engineered wood panel according to any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Disperse basalt fibers in water to make a fiber suspension; (2) The difluoromethoxyacrylate emulsion, fiber suspension, silane coupling agent and additives are modified, and after the modification is completed, the mixture is cooled, cured and filtered to produce the modifier. (3) Mix gel-type adhesive with modifier to make modified adhesive, then make adhesive material by combining substrate, inorganic mineral powder and modified adhesive, and then press the adhesive material into low water absorption and crack-resistant inorganic artificial board.

6. The preparation method according to claim 5, characterized in that, The conditions for modification treatment include: temperature 35~45 ℃, rotation speed 800~5000 rpm.

7. The preparation method according to claim 5 or 6, characterized in that, The modification conditions included: the rotation speed of adding the fiber suspension and silane coupling agent was 3000 rpm, and the pH was 7.5~8.

5.

8. The preparation method according to claim 5, characterized in that, The emulsification conditions for the difluoromethoxyacrylate emulsion include: a dropping rate of 1.5~5.0 g / min and a rotation speed of 5000~8000 rpm for adding difluoromethoxyacrylate.

9. The preparation method according to claim 5 or 8, characterized in that, The emulsion particle size of the difluoromethoxyacrylate emulsion is 100~250 nm.

10. The preparation method according to claim 5, characterized in that, The pressing process uses cold pressing, with a pressure of 10~20MPa.

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