Carbonized wood multi-isolation-layer composite floor and preparation method thereof

Abstract

The invention relates to the technical field of composite floor preparation, in particular to a carbonized wood multi-isolation-layer composite floor and a preparation method thereof. A latticed base material is obtained; a base fiber board, a first latticed base material, a stress absorption layer board, a second latticed base material and the carbonized wood surface layer are sequentially laid from bottom to top, cold pressing is conducted to obtain a composite floor board blank, the cold pressing pressure is adjusted according to the interlayer contact resistance of the first latticed base material, and the stress absorption layer board is obtained. The relative laying direction of the first latticed base material and the second latticed base material is determined according to the average water content and the water content distribution variance; pre-hot-pressing is conducted on the composite floor plate blank; according to the thickness change rate, determining a down-regulation step value of the hot-pressing pressure in a staged down-regulation hot-pressing mode; and the composite floor board blank is subjected to hot pressing to obtain the finished composite floor. The performance stability of the composite floor is improved.

Description

Technical Field

[0001] This invention relates to the field of composite flooring preparation technology, and in particular to a carbonized wood multi-layer composite flooring and its preparation method. Background Technology

[0002] In existing technologies, carbonized wood multi-layer composite flooring is a new type of composite flooring that combines carbonized wood material with a multi-layer insulation structure. Its preparation method involves carbonization treatment, multi-layer structure laying, and hot pressing molding processes. The carbonized wood material, through high-temperature carbonization treatment, has excellent corrosion resistance, insect resistance, and moisture resistance. Traditional carbonized wood flooring is prone to poor dimensional stability due to uneven moisture content distribution during the preparation process, which affects the service life of the flooring. Carbonized wood multi-layer composite flooring can be used as a home floor decoration material. Its low moisture content and corrosion resistance make it particularly suitable for humid environments such as kitchens and bathrooms. In commercial places, it has good sound insulation and impact resistance, making it suitable for high-traffic areas. Due to the weather resistance and insect resistance of carbonized wood material, it can also be used in outdoor facilities such as balconies, terraces, and boardwalks, especially suitable for humid or variable climate environments.

[0003] Chinese Patent Publication No. CN111173226A discloses a composite flame-retardant solid wood flooring and its preparation process. The composite flame-retardant solid wood flooring comprises, from top to bottom, a topcoat layer, a carbonized flame-retardant board layer one, a flame-retardant layer one, a solid wood flame-retardant board layer, a flame-retardant layer two, and a carbonized flame-retardant board layer two. The thickness ratio of the carbonized flame-retardant board layer one, flame-retardant layer one, solid wood flame-retardant board layer two, flame-retardant layer two, and carbonized flame-retardant board layer two is 10-14:2.5-3.5:35-48:2.5-3.5:10-14. Therefore, it is evident that when the composite flame-retardant solid wood flooring and its preparation process are applied in geothermal environments, such as underfloor heating or areas with significant humidity fluctuations, the different expansion and contraction coefficients of the various layers of the flooring in response to temperature and humidity changes lead to internal stress accumulation, resulting in warping, deformation, cracking, or cracking at the joints of the flooring. Summary of the Invention

[0004] Therefore, the present invention provides a carbonized wood multi-insulation layer composite floor and its preparation method to overcome the problems of existing carbonized wood flooring when applied in geothermal environments, such as underfloor heating or areas with obvious alternation of dry and wet conditions. These problems arise because the different expansion and contraction coefficients of the various layers of the flooring material respond to changes in temperature and humidity, leading to internal stress accumulation, which in turn causes the flooring to warp, deform, crack, or crack at the joints.

[0005] To achieve the above objectives, the present invention provides a method for preparing carbonized wood multi-layer composite flooring, comprising:

[0006] The wood blanks are carbonized to obtain a carbonized wood surface layer, and the average moisture content and moisture content distribution variance of the carbonized wood surface layer are detected.

[0007] An alloy insulating layer is embedded in a mold to obtain a mesh-like substrate;

[0008] The base fiberboard, the first mesh substrate, the stress-absorbing layer, the second mesh substrate, and the carbonized wood surface layer are laid in sequence from bottom to top, and then cold-pressed to obtain the composite flooring blank.

[0009] The cold pressing pressure during the cold pressing process is adjusted according to the interlayer contact resistance of the first mesh substrate, and the relative laying direction of the first mesh substrate and the second mesh substrate is determined according to the average moisture content and the variance of the moisture content distribution.

[0010] The composite flooring blank is preheated and pressed to obtain the thickness change rate of the composite flooring blank;

[0011] The step size for reducing the hot pressing pressure in the staged hot pressing method is determined based on the thickness change rate.

[0012] The composite flooring blank is hot-pressed according to the described staged downward hot-pressing method to obtain the finished composite flooring.

[0013] Further, the process of determining the relative laying direction of the first mesh substrate and the second mesh substrate based on the average moisture content and the variance of the moisture content distribution includes:

[0014] The average moisture content and the variance of the moisture content distribution are obtained respectively.

[0015] If the average moisture content is less than or equal to the preset moisture content and the moisture content distribution variance is less than or equal to the preset variance, then the main direction of the first mesh substrate is laid parallel to the long side of the composite flooring blank, and the main direction of the second mesh substrate is laid perpendicular to the long side of the composite flooring blank.

[0016] If the average moisture content is greater than the preset moisture content and the moisture content distribution variance is less than or equal to the preset variance, then the main direction of the first mesh substrate is laid parallel to the long side direction, and the main direction of the second mesh substrate is laid at an acute angle to the long side direction.

[0017] If the average moisture content is less than or equal to the preset moisture content and the moisture content distribution variance is greater than the preset variance, then the main mesh direction of the first mesh substrate and the main mesh direction of the second mesh substrate are laid at an angle to the long side direction, and the angle between the main mesh direction of the first mesh substrate and the main mesh direction of the second mesh substrate is an acute angle.

[0018] If the average moisture content is greater than the preset moisture content and the moisture content distribution variance is greater than the preset variance, then the main direction of the first mesh substrate is laid at an acute angle to the long side direction, the main direction of the second mesh substrate is laid at an acute angle to the long side direction, and the acute angle between the main direction of the first mesh substrate and the long side direction is smaller than the acute angle between the main direction of the second mesh substrate and the long side direction.

[0019] Furthermore, the variance of the moisture content distribution is the average of the sum of squares of the differences between the moisture content of several detection points on the surface of the carbonized wood layer and the average moisture content.

[0020] Furthermore, the surface of the carbonized wood layer is divided into several testing areas according to a square of unit length, and the center point of the testing area is the testing point for moisture content.

[0021] Furthermore, the process of adjusting the cold pressing pressure according to the interlayer contact resistance of the first mesh-like substrate includes:

[0022] The interlayer contact resistance of the first mesh-like substrate during cold pressing was obtained;

[0023] The interlayer contact resistance is compared with a preset resistance;

[0024] If the interlayer contact resistance measured in several consecutive samples is greater than or equal to the preset resistance, the cold pressing pressure is increased until the interlayer contact resistance decreases and the cold pressing pressure returns to the set value.

[0025] Furthermore, the process of determining the step size value of the hot pressing pressure reduction method in the staged reduction hot pressing mode based on the thickness change rate includes:

[0026] Obtain the thickness change rate;

[0027] The thickness change rate is compared with the preset change rate;

[0028] If the thickness change rate is greater than or equal to the preset change rate, then the downward adjustment step size is reduced.

[0029] Furthermore, the thickness change rate is the ratio of the difference between the thickness of the composite floorboard blank at the start of preheating and the thickness of the composite floorboard blank at the end of preheating to the thickness of the composite floorboard blank at the start of preheating.

[0030] Furthermore, the increase in the cold pressing pressure is determined based on the difference between the continuously collected maximum interlayer contact resistance and the preset resistance.

[0031] Furthermore, the step size for the reduction is the hot-press pressure at the previous adjustment time minus the product of the reduction factor and the hot-press pressure at the previous adjustment time.

[0032] This invention provides a carbonized wood multi-layer composite flooring, comprising:

[0033] The substrate is laid in layers from bottom to top: base fiberboard, first mesh substrate, stress-absorbing layer, second mesh substrate, and carbonized wood surface layer.

[0034] The thickness of the carbonized wood surface layer is 2-4 mm;

[0035] The first and second mesh-like substrates are both mesh structures made of nickel-chromium alloy, with a mesh aperture of 2-5 mm and a wire diameter of 0.3-0.6 mm.

[0036] The stress-absorbing layer is a polyurethane elastomer layer with a thickness of 1-2 mm;

[0037] The base fiberboard is a high-density fiberboard with a thickness of 8-12 mm.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows: The method of the present invention obtains a carbonized wood surface layer by carbonizing the wood blank and detecting its average moisture content and moisture content distribution variance, thereby realizing the internal moisture state of the carbonized wood surface layer. The drier the surface layer, the greater its potential tendency to absorb moisture and expand in the use environment, and the stronger its memory elasticity in trying to restore its original state. It may generate greater internal stress in subsequent processing. By embedding the alloy insulating layer into the mold to form a grid-like substrate, the shrinkage force generated by the alloy insulating layer after heating is utilized to effectively offset the internal stress generated by the shrinkage and expansion of the wood layer caused by temperature and humidity changes, thereby reducing the overall deformation risk of the composite flooring; by laying the base fiberboard, the first grid-like substrate, and the stress layer in the order from bottom to top, the method can effectively counteract the internal stress generated by the shrinkage and expansion of the wood layer caused by temperature and humidity changes. The composite structure consists of an absorption layer, a second mesh substrate, and a carbonized wood surface layer. During cold pressing, the cold pressing pressure is adjusted based on the interlayer contact resistance of the first mesh substrate, enabling dynamic control of the tightness of the interlayer bonding and ensuring a good stress transmission path between different material layers. By determining the relative laying direction of the first and second mesh substrates based on the average moisture content and moisture content distribution variance of the carbonized wood surface layer, the composite structure possesses anisotropic adaptability. This allows it to maintain structural stability when facing stress changes in different directions. Furthermore, when the local heating is activated and the ambient temperature exceeds the phase transition temperature of the mesh substrate, it actively contracts, applying prestress to the mesh to tighten the floor structure and actively counteract the surface expansion tendency that may be caused by temperature increases.

[0039] Furthermore, the method of the present invention adjusts the relative laying direction of the first and second mesh-like substrates under different conditions. When the wood blank has reached or fallen below the equilibrium moisture content of the usage environment, the possibility of future moisture absorption and expansion is greater than drying shrinkage, and the internal moisture content of the wood is very uniform, resulting in a small overall deformation trend. In this case, by laying the main mesh direction of the first mesh-like substrate parallel to the long side of the composite flooring blank and laying the main mesh direction of the second mesh-like substrate perpendicular to the long side of the composite flooring blank, the two meshes provide the strongest constraint in both the longitudinal and transverse directions of the board, forming an orthogonal mesh reinforcement structure that uniformly resists minor stresses that may come from all directions, improving dimensional stability. When the wood blank is relatively moist, it will mainly experience drying shrinkage during use, but the shrinkage is uniform. The main challenge is to resist the transverse shrinkage, which has the largest shrinkage rate along the wood grain direction. By laying the main mesh direction of the first mesh-like substrate parallel to the long side and laying the main mesh direction of the second mesh-like substrate at an acute angle to the long side, the transverse shrinkage is constrained. When the overall dryness of the wood blank is suitable... However, under conditions where uneven internal moisture content and stress hotspots could lead to uneven expansion or complex internal shear stress, resulting in a high risk of warping, the composite flooring can be improved by laying the main mesh directions of the first and second mesh substrates at an angle to their long sides, with the angle between the main mesh directions of the first and second mesh substrates being acute. This disperses the uneven stress in multiple directions, thus suppressing deformation caused by excessive local stress. Furthermore, when the wood blank is both wet and uneven, leading to severe and uneven shrinkage and subsequent shrinkage and shear stress that could cause cracking and warping, the composite flooring can be further improved by laying the main mesh directions of the first and second mesh substrates at acute angles to their long sides, with the acute angle between the main mesh directions of the first and second mesh substrates being smaller than that of the second mesh substrate. This provides relatively balanced constraint forces in multiple directions—longitudinal, transverse, and diagonal—to cope with complex and severe stress changes, thereby improving the stability of the composite flooring's performance.

[0040] Furthermore, the method of the present invention increases the cold pressing pressure. Since the template with uneven humidity distribution exhibits uneven moisture absorption performance under humid conditions, increasing the cold pressing pressure during cold pressing ensures that each layer is firmly bonded and fixed to resist the problem of poor internal stress uniformity caused by uneven moisture absorption performance, thereby preventing interlayer delamination.

[0041] Furthermore, the method of the present invention obtains the thickness change rate of the composite flooring blank through preheating and pressing, and determines the step size value of the hot pressing pressure reduction method in a staged manner based on the change rate, so as to avoid uneven stress distribution inside the composite structure due to excessive or insufficient hot pressing pressure. The cold pressing pressure determines the initial density of the blank. During the hot pressing activation stage, the mesh substrate will do work due to heat shrinkage. The hot pressing pressure will restrict its shrinkage, resulting in the inability to effectively release stress or even damage the structure and the inability to effectively guide its shrinkage direction, resulting in structural distortion. By gradually reducing the pressure thereafter, a gradual environment is provided for the shrinkage of the mesh substrate, guiding its shrinkage force to act directionally on the overall structure, thereby improving the stability of the mechanical properties of the composite board.

[0042] Furthermore, the method of the present invention hot-presses the composite flooring blank in a phased downward hot-pressing manner, ensuring that the composite flooring can fully release internal stress during the molding process, improving the bonding strength between material layers, thereby enhancing its dimensional stability and durability in a geothermal environment.

[0043] Furthermore, the composite flooring of the present invention comprises, from bottom to top, a base fiberboard, a first mesh substrate, a stress-absorbing layer, a second mesh substrate, and a carbonized wood surface layer, wherein the thickness of the carbonized wood surface layer is controlled at 2-4 mm to ensure good carbonization stability; the first and second mesh substrates are made of nickel-chromium alloy, possessing good thermal conductivity and mechanical shrinkage characteristics; the stress-absorbing layer is made of polyurethane elastomer, possessing good elasticity and stress buffering capacity, and can effectively absorb local stress caused by differences in material expansion and contraction; the base fiberboard is a high-density fiberboard, providing support and stability for the overall structure. Attached Figure Description

[0044] Figure 1 This is an overall flowchart of the preparation method of carbonized wood multi-insulation layer composite flooring according to an embodiment of the present invention;

[0045] Figure 2 A flowchart illustrating the determination of the relative laying directions of the first and second mesh substrates in the preparation method of the carbonized wood multi-insulation layer composite flooring according to an embodiment of the present invention.

[0046] Figure 3 This is a flowchart illustrating the adjustment of cold pressing pressure in the preparation method of carbonized wood multi-insulation layer composite flooring according to an embodiment of the present invention;

[0047] Figure 4 This is a schematic diagram of the structure of the carbonized wood multi-insulation layer composite flooring according to an embodiment of the present invention;

[0048] Explanation of reference numerals: 1-Base fiberboard, 2-First mesh substrate, 3-Stress-absorbing layer, 4-Second mesh substrate, 5-The carbonized wood surface layer. Detailed Implementation

[0049] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0050] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0051] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0052] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0053] Please see Figure 1 , Figure 2 , Figure 3 as well as Figure 4 The diagrams shown are, respectively, an overall flowchart of the carbonized wood multi-insulation layer composite flooring and its preparation method according to an embodiment of the present invention, a flowchart for determining the relative laying direction of the first and second mesh substrates, a flowchart for adjusting the cold pressing pressure, and a structural schematic diagram of the carbonized wood multi-insulation layer composite flooring. The present invention provides a method for preparing carbonized wood multi-insulation layer composite flooring, comprising:

[0054] The wood blanks are carbonized to obtain a carbonized wood surface layer, and the average moisture content and moisture content distribution variance of the carbonized wood surface layer are detected.

[0055] An alloy insulating layer is embedded in a mold to obtain a mesh-like substrate;

[0056] The base fiberboard, the first mesh substrate, the stress-absorbing layer, the second mesh substrate, and the carbonized wood surface layer are laid in sequence from bottom to top, and then cold-pressed to obtain the composite flooring blank.

[0057] The cold pressing pressure during the cold pressing process is adjusted according to the interlayer contact resistance of the first mesh substrate, and the relative laying direction of the first mesh substrate and the second mesh substrate is determined according to the average moisture content and the variance of the moisture content distribution.

[0058] The composite flooring blank is preheated and pressed to obtain the thickness change rate of the composite flooring blank;

[0059] The step size for reducing the hot pressing pressure in the staged hot pressing method is determined based on the thickness change rate.

[0060] The composite flooring blank is hot-pressed according to the described staged downward hot-pressing method to obtain the finished composite flooring.

[0061] Specifically, during the process of laying the base fiberboard, the first grid substrate, the stress-absorbing layer, the second grid substrate, and the carbonized wood surface layer in the order from bottom to top, adhesive needs to be added between each pair of adjacent boards.

[0062] Specifically, the carbonization conditions are as follows: the carbonization temperature ranges from [180℃ to 220℃], the carbonization time ranges from [2 hours to 4 hours], and the oxygen concentration is below 5%. Under the condition that the wood blank material is oak and the wood blank thickness does not exceed 5cm, the preferred embodiment of the carbonization temperature is 200℃ and the preferred embodiment of the carbonization time is 3 hours.

[0063] Specifically, the carbonization process is carried out in a reaction vessel. The laid-up material layers are cold-pressed and bonded using a cold press, and the material layers and adhesive are cured using a hot press.

[0064] Specifically, the cold pressing temperature is 24℃, and the holding time after cold pressing is 15 minutes;

[0065] When the adhesive is urea-formaldehyde resin, the hot-pressing temperature is 120℃, and the total hot-pressing time ranges from 4 minutes to 6 minutes.

[0066] Those skilled in the art can adjust the actual total hot pressing time, actual cold pressing temperature, and actual holding time according to the actual situation.

[0067] Specifically, the interlayer contact resistance is measured by setting electrodes on the upper and lower surfaces of the first mesh substrate to measure the contact resistance between the first mesh substrate and the adjacent layers.

[0068] Specifically, the moisture content is measured using a microwave moisture meter; the thickness of the composite flooring blank is measured using a displacement sensor.

[0069] In practice, the method of this invention carbonizes the wood blank to obtain a carbonized wood surface layer and detects its average moisture content and moisture content distribution variance, thereby achieving control over the internal moisture state of the carbonized wood surface layer. The drier the surface layer, the greater its potential for moisture absorption and expansion in the usage environment, and the stronger its memory elasticity in attempting to restore its original state. This may generate greater internal stress in subsequent processing. By embedding an alloy insulating layer into a mold to form a grid-like substrate, its characteristic of generating shrinkage force after heating is utilized to effectively offset the internal stress generated by the shrinkage and expansion of the wood layer caused by temperature and humidity changes, thereby reducing the overall deformation risk of the composite flooring. The method involves laying the base fiberboard, the first grid-like substrate, the stress-absorbing layer, and the second layer in a bottom-to-top sequence. The composite structure comprises a grid-like substrate and a carbonized wood surface layer. During cold pressing, the cold pressing pressure is adjusted based on the interlayer contact resistance of the first grid-like substrate, enabling dynamic control of the tightness of the interlayer bonding and ensuring a good stress transmission path between different material layers. By determining the relative laying direction of the first and second grid-like substrates based on the average moisture content and moisture content distribution variance of the carbonized wood surface layer, the composite structure possesses anisotropic adaptability. This allows it to maintain structural stability when facing stress changes in different directions. Furthermore, when the geothermal system is activated and the ambient temperature exceeds the phase transition temperature of the grid-like substrate, it actively contracts, applying prestress to the grid to tighten the floor structure and actively counteract the surface expansion tendency that may be caused by temperature increases.

[0070] Specifically, the process of determining the laying rotation angle of the first mesh substrate and the second mesh substrate based on the average moisture content and the variance of the moisture content distribution includes:

[0071] The average moisture content and the variance of the moisture content distribution are obtained respectively.

[0072] If the average moisture content is less than or equal to the preset moisture content and the moisture content distribution variance is less than or equal to the preset variance, then the main direction of the first mesh substrate is laid parallel to the long side of the composite flooring blank, and the main direction of the second mesh substrate is laid perpendicular to the long side of the composite flooring blank.

[0073] If the average moisture content is greater than the preset moisture content and the moisture content distribution variance is less than or equal to the preset variance, then the main direction of the first mesh substrate is laid parallel to the long side direction, and the main direction of the second mesh substrate is laid at an acute angle to the long side direction.

[0074] If the average moisture content is less than or equal to the preset moisture content and the moisture content distribution variance is greater than the preset variance, then the main mesh direction of the first mesh substrate and the main mesh direction of the second mesh substrate are laid at an angle to the long side direction, and the angle between the main mesh direction of the first mesh substrate and the main mesh direction of the second mesh substrate is an acute angle.

[0075] If the average moisture content is greater than the preset moisture content and the moisture content distribution variance is greater than the preset variance, then the main direction of the first mesh substrate is laid at an acute angle to the long side direction, the main direction of the second mesh substrate is laid at an acute angle to the long side direction, and the acute angle between the main direction of the first mesh substrate and the long side direction is smaller than the acute angle between the main direction of the second mesh substrate and the long side direction.

[0076] Specifically, the main direction of the grid is the main extension direction of the continuous metal wire bundle.

[0077] For rectangular grids, the direction of the longer side of the grid is taken as the main direction of the grid. For rhomboid grids, the direction of the grid's axis of symmetry is taken as the main direction of the grid.

[0078] Specifically, in laying the main direction of the first mesh substrate parallel to the long side direction, and laying the main direction of the second mesh substrate at an acute angle to the long side direction, the acute angle between the main direction of the second mesh substrate and the long side direction is 45°.

[0079] In laying the main grid direction of the first grid substrate and the main grid direction of the second grid substrate at an angle to the long side direction, the angle between the main grid direction of the first grid substrate and the long side direction is 22.5°, and the angle between the main grid direction of the second grid substrate and the long side direction is 67.5°.

[0080] In the case where the main direction of the grid of the first grid-shaped substrate is laid at an acute angle to the long side direction, and the main direction of the grid of the second grid-shaped substrate is laid at an acute angle to the long side direction, the angle between the main direction of the grid of the first grid-shaped substrate and the long side direction is 30°, and the angle between the main direction of the grid of the second grid-shaped substrate and the long side direction is 60°.

[0081] Specifically, under the conditions that the adhesive is urea-formaldehyde resin, the blank material is oak, and the length of the composite flooring blank does not exceed 2m, the general range of the preset moisture content is [5%, 9%], and the general range of the preset variance is [1%]. 2 2% 2 The preferred embodiment has a preset moisture content of 8% and a preset variance of 1.5%. 2 .

[0082] Those skilled in the art will understand that the range of preset moisture content and preset variance provided in this embodiment, as well as the preferred embodiment, are the values ​​that best address the technical problem solved by the present invention, under the conditions that the adhesive is urea-formaldehyde resin, the blank material is oak, and the length of the composite flooring blank does not exceed 2m. In actual applications or experiments, those skilled in the art can make adaptive adjustments to the preset moisture content and preset variance according to the actual application environment and application scenario.

[0083] Specifically, the variance of the moisture content distribution is the average of the sum of squares of the differences between the moisture content of several detection points on the surface of the carbonized wood and the average moisture content.

[0084] Specifically, the surface of the carbonized wood layer is divided into several testing areas according to a square of unit length, and the center point of the testing area is the testing point for moisture content.

[0085] Specifically, the moisture content is detected using a microwave moisture meter. For example, a carbonized wood surface layer with a length of 2000 mm and a width of 200 mm is divided into 10 regions along its length, each region measuring 200 mm × 200 mm. The probe of the microwave moisture meter is vertically aligned with the detection point to detect and record the moisture content of each detection point.

[0086] Specifically, the rotational laying of the first and second mesh substrates is carried out by a robotic arm.

[0087] In practice, the method of this invention adjusts the relative laying direction of the first and second mesh-like substrates under different conditions. When the wood blank has reached or fallen below the equilibrium moisture content of the usage environment, the possibility of future moisture absorption and expansion is greater than drying shrinkage, and the internal moisture content of the wood is very uniform, resulting in a small overall deformation trend. In this case, by laying the main mesh direction of the first mesh-like substrate parallel to the long side of the composite flooring blank and laying the main mesh direction of the second mesh-like substrate perpendicular to the long side of the composite flooring blank, the two meshes provide the strongest constraint in both the longitudinal and transverse directions of the board, forming an orthogonal mesh reinforcement structure that uniformly resists minor stresses that may come from all directions, improving dimensional stability. When the wood blank is relatively moist, it will mainly experience drying shrinkage during use, but the shrinkage is uniform. The main challenge is to resist the transverse shrinkage, which has the largest shrinkage rate along the wood grain direction. By laying the main mesh direction of the first mesh-like substrate parallel to the long side and laying the main mesh direction of the second mesh-like substrate at an acute angle to the long side, the transverse shrinkage is constrained. When the overall dryness of the wood blank is appropriate... However, under conditions where uneven internal moisture content and stress hotspots could lead to uneven expansion or complex internal shear stress, resulting in a high risk of warping, the composite flooring can be improved by laying the main mesh directions of the first and second mesh substrates at an angle to their long sides, with the angle between the main mesh directions of the first and second mesh substrates being acute. This disperses the uneven stress in multiple directions, thus suppressing deformation caused by excessive local stress. Furthermore, when the wood blank is both wet and uneven, leading to severe and uneven shrinkage and subsequent shrinkage and shear stress that could cause cracking and warping, the composite flooring can be further improved by laying the main mesh directions of the first and second mesh substrates at acute angles to their long sides, with the acute angle between the main mesh directions of the first and second mesh substrates being smaller than that of the second mesh substrate. This provides relatively balanced constraint forces in multiple directions—longitudinal, transverse, and diagonal—to cope with complex and severe stress changes, thereby improving the stability of the composite flooring's performance.

[0088] Specifically, the process of adjusting the cold pressing pressure based on the interlayer contact resistance of the first mesh-like substrate includes:

[0089] The interlayer contact resistance of the first mesh-like substrate during cold pressing was obtained;

[0090] The interlayer contact resistance is compared with a preset resistance;

[0091] If the interlayer contact resistance measured in several consecutive samples is greater than or equal to the preset resistance, the cold pressing pressure is increased until the interlayer contact resistance decreases and the cold pressing pressure returns to the set value.

[0092] Specifically, the mesh size is 2–5 mm, the wire diameter is 0.3–0.6 mm, and the surface area of ​​the composite flooring blank does not exceed 5 m². 2 Under these conditions, the general range of the preset resistor value is [10mΩ, 50mΩ], and the preferred embodiment of the preset resistor is 30mΩ.

[0093] Those skilled in the art will understand that the selectable range of the preset resistor and the preferred embodiment provided in this example are based on the following conditions: the mesh aperture is 2-5 mm, the wire diameter is 0.3-0.6 mm, and the surface area of ​​the composite flooring blank does not exceed 5 m². 2 The value selected under the given conditions is the one that best addresses the technical problem solved by the present invention. In actual applications or experiments, those skilled in the art can make adaptive adjustments to the preset resistance according to the actual application environment and application scenario.

[0094] Specifically, the condition for increasing the cold pressing pressure until the interlayer contact resistance decreases and the cold pressing pressure recovers to the set value is that the interlayer contact resistance of five consecutive samples is greater than or equal to the preset resistance.

[0095] In practice, if the difference between the maximum interlayer contact resistance and the preset resistance exceeds 1 mΩ, the cold pressing pressure is increased by 0.01 MPa. For example, if the initial cold pressing pressure is 0.8 MPa, and the interlayer contact resistance of five consecutive samples is greater than or equal to 30 mΩ, and the maximum interlayer contact resistance is 35 mΩ, then the pressure is increased to 0.8 MPa + 0.01 MPa × 5 = 0.85 MPa, and maintained at 0.85 MPa until the resistance value drops below 30 mΩ, then the pressure is restored to 0.8 MPa.

[0096] In practice, the method of the present invention increases the cold pressing pressure. Since the template with uneven humidity distribution exhibits uneven moisture absorption performance under humid conditions, increasing the cold pressing pressure during cold pressing ensures that each layer is firmly bonded and fixed to resist the problem of poor internal stress uniformity caused by uneven moisture absorption performance, thereby preventing interlayer delamination.

[0097] Specifically, the process of determining the step size value of the hot pressing pressure reduction method based on the thickness change rate includes:

[0098] Obtain the thickness change rate;

[0099] The thickness change rate is compared with the preset change rate;

[0100] If the thickness change rate is greater than or equal to the preset change rate, then the downward adjustment step size is reduced.

[0101] Specifically, the thickness change rate is the ratio of the difference between the thickness of the composite floorboard blank at the start of preheating and the thickness of the composite floorboard blank at the end of preheating to the thickness of the composite floorboard blank at the start of preheating.

[0102] Specifically, the increase in cold pressing pressure is determined based on the difference between the continuously collected maximum interlayer contact resistance and the preset resistance.

[0103] Specifically, the downward adjustment step size is the hot-press pressure at the previous adjustment time minus the product of the downward adjustment factor and the hot-press pressure at the previous adjustment time.

[0104] Specifically, the phased reduction hot pressing method divides the total hot pressing time into several equal hot pressing phase durations, and the hot pressing pressure within each hot pressing phase duration is reduced compared to the hot pressing pressure within the adjacent previous hot pressing phase duration by a reduction step value.

[0105] The relationship between the duration of the hot pressing stage and the number of adjustment moments is: the number of hot pressing stages = the number of adjustment moments + 1.

[0106] Specifically, the mesh size is 2–5 mm, the wire diameter is 0.3–0.6 mm, and the surface area of ​​the composite flooring blank does not exceed 5 m². 2 Under these conditions, the general range of the preset rate of change is [0.01, 0.03], and the preferred embodiment of the preset rate of change is 0.015.

[0107] Those skilled in the art will understand that the selectable range of the preset change rate and the preferred embodiment provided in this example are based on the condition that the mesh aperture is 2-5 mm, the wire diameter is 0.3-0.6 mm, and the surface area of ​​the composite flooring blank does not exceed 5 m². 2 The value selected under the given conditions is the one that best addresses the technical problem solved by the present invention. In actual applications or experiments, those skilled in the art can adaptively adjust the preset rate of change according to the actual application environment and application scenario.

[0108] In implementation, if the difference between the preset change rate and the thickness change rate exceeds 1%, the reduction factor increases to 1.05 times the original reduction factor, thereby reducing the reduction compensation value. For example, if the difference between the preset change rate and the thickness change rate is 2%, the current reduction factor is 0.7, the initial hot pressing pressure is 1.2 MPa, the total hot pressing time is 6 minutes, the hot pressing stage duration is 2 minutes, and the original reduction compensation value is 1.2 MPa - 1.2 MPa × 0.7 = 0.36 MPa.

[0109] The reduction factor increases to 0.7 × 1.05 × 1.05 = 0.77175 ≈ 0.77, and the reduction compensation value decreases to 1.2 MPa - 1.2 MPa × 0.77 = 0.276 MPa.

[0110] In practice, the method of this invention obtains the thickness change rate of the composite flooring blank through preheating and pressing, and determines the step size of the hot pressing pressure reduction method based on the change rate. This avoids uneven stress distribution inside the composite structure due to excessive or insufficient hot pressing pressure. The cold pressing pressure determines the initial density of the blank. During the hot pressing activation stage, the mesh substrate shrinks due to heat and does work. The hot pressing pressure restricts its shrinkage, resulting in stress that cannot be effectively released or even damages the structure and cannot effectively guide its shrinkage direction, leading to structural distortion. By gradually reducing the pressure thereafter, a gradual environment is provided for the shrinkage of the mesh substrate, guiding its shrinkage force to act directionally on the overall structure, thereby improving the stability of the mechanical properties of the composite board.

[0111] In practice, the method of the present invention hot-presses the composite flooring blank in a phased downward hot-pressing manner, ensuring that the composite flooring can fully release internal stress during the molding process, improve the bonding strength between material layers, and thus enhance its dimensional stability and durability in the geothermal environment.

[0112] This invention provides an embodiment of a carbonized wood multi-layer composite flooring, comprising:

[0113] The following layers are laid sequentially from bottom to top: base fiberboard 1, first mesh substrate 2, stress-absorbing layer 3, second mesh substrate 4, and carbonized wood surface layer 5.

[0114] The thickness of the carbonized wood surface layer 5 is 2-4 mm;

[0115] The first mesh substrate 2 and the second mesh substrate 4 are mesh structures made of nickel-chromium alloy, with a mesh aperture of 2-5 mm and a wire diameter of 0.3-0.6 mm.

[0116] The stress-absorbing layer 3 is a polyurethane elastomer layer with a thickness of 1-2 mm;

[0117] The base fiberboard 1 is a high-density fiberboard with a thickness of 8-12 mm.

[0118] In implementation, the composite flooring of the present invention comprises, from bottom to top, a base fiberboard 1, a first mesh substrate 2, a stress-absorbing layer 3, a second mesh substrate 4, and a carbonized wood surface layer 5, wherein the thickness of the carbonized wood surface layer 5 is controlled at 2-4 mm to ensure good carbonization stability; the first mesh substrate 2 and the second mesh substrate 4 are made of nickel-chromium alloy, possessing good thermal conductivity and mechanical shrinkage characteristics; the stress-absorbing layer 3 is made of polyurethane elastomer, possessing good elasticity and stress buffering capacity, and can effectively absorb local stress caused by differences in material expansion and contraction; the base fiberboard 1 is a high-density fiberboard, providing support and stability for the overall structure.

[0119] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing carbonized wood multi-layer composite flooring, characterized in that, include: The wood blanks are carbonized to obtain a carbonized wood surface layer, and the average moisture content and moisture content distribution variance of the carbonized wood surface layer are detected. An alloy insulating layer is embedded in a mold to obtain a mesh-like substrate; The base fiberboard, the first mesh substrate, the stress-absorbing layer, the second mesh substrate, and the carbonized wood surface layer are laid in sequence from bottom to top, and then cold-pressed to obtain the composite flooring blank. The cold pressing pressure during the cold pressing process is adjusted according to the interlayer contact resistance of the first mesh substrate, and the relative laying direction of the first mesh substrate and the second mesh substrate is determined according to the average moisture content and the variance of the moisture content distribution. The composite flooring blank is preheated and pressed to obtain the thickness change rate of the composite flooring blank; The step size for reducing the hot pressing pressure in the staged hot pressing method is determined based on the thickness change rate. The composite flooring blank is hot-pressed according to the described staged downward hot-pressing method to obtain the finished composite flooring.

2. The method for preparing carbonized wood multi-layer composite flooring according to claim 1, characterized in that, The process of determining the relative laying direction of the first mesh substrate and the second mesh substrate based on the average moisture content and the variance of the moisture content distribution includes: The average moisture content and the variance of the moisture content distribution are obtained respectively. If the average moisture content is less than or equal to the preset moisture content and the moisture content distribution variance is less than or equal to the preset variance, then the main direction of the first mesh substrate is laid parallel to the long side of the composite flooring blank, and the main direction of the second mesh substrate is laid perpendicular to the long side of the composite flooring blank. If the average moisture content is greater than the preset moisture content and the moisture content distribution variance is less than or equal to the preset variance, then the main direction of the first mesh substrate is laid parallel to the long side direction, and the main direction of the second mesh substrate is laid at an acute angle to the long side direction. If the average moisture content is less than or equal to the preset moisture content and the moisture content distribution variance is greater than the preset variance, then the main mesh direction of the first mesh substrate and the main mesh direction of the second mesh substrate are laid at an angle to the long side direction, and the angle between the main mesh direction of the first mesh substrate and the main mesh direction of the second mesh substrate is an acute angle. If the average moisture content is greater than the preset moisture content and the moisture content distribution variance is greater than the preset variance, then the main direction of the first mesh substrate is laid at an acute angle to the long side direction, the main direction of the second mesh substrate is laid at an acute angle to the long side direction, and the acute angle between the main direction of the first mesh substrate and the long side direction is smaller than the acute angle between the main direction of the second mesh substrate and the long side direction.

3. The method for preparing carbonized wood multi-layer composite flooring according to claim 2, characterized in that, The variance of the moisture content distribution is the average of the sum of squares of the differences between the moisture content of several detection points on the surface of the carbonized wood and the average moisture content.

4. The method for preparing carbonized wood multi-layer composite flooring according to claim 3, characterized in that, The surface of the carbonized wood is divided into several testing areas according to a square of unit length, and the center point of the testing area is the testing point for moisture content.

5. The method for preparing carbonized wood multi-layer composite flooring according to claim 4, characterized in that, The process of adjusting the cold pressing pressure based on the interlayer contact resistance of the first mesh substrate includes: The interlayer contact resistance of the first mesh-like substrate during cold pressing was obtained; The interlayer contact resistance is compared with a preset resistance; If the interlayer contact resistance measured in several consecutive samples is greater than or equal to the preset resistance, the cold pressing pressure is increased until the interlayer contact resistance decreases and the cold pressing pressure returns to the set value.

6. The method for preparing carbonized wood multi-layer composite flooring according to claim 5, characterized in that, The process of determining the step size value of the hot pressing pressure reduction method based on the thickness change rate includes: Obtain the thickness change rate; The thickness change rate is compared with the preset change rate; If the thickness change rate is greater than or equal to the preset change rate, then the downward adjustment step size is reduced.

7. The method for preparing carbonized wood multi-layer composite flooring according to claim 6, characterized in that, The thickness change rate is the ratio of the difference between the thickness of the composite floorboard blank at the beginning of preheating and the thickness of the composite floorboard blank at the end of preheating to the thickness of the composite floorboard blank at the beginning of preheating.

8. The method for preparing carbonized wood multi-layer composite flooring according to claim 7, characterized in that, The increase in cold pressing pressure is determined based on the difference between the continuously collected maximum interlayer contact resistance and the preset resistance.

9. The method for preparing carbonized wood multi-layer composite flooring according to claim 8, characterized in that, The downward adjustment step size is the hot-press pressure at the previous adjustment time minus the product of the downward adjustment factor and the hot-press pressure at the previous adjustment time.

10. A carbonized wood multi-insulation layer composite flooring prepared using the preparation method of carbonized wood multi-insulation layer composite flooring according to any one of claims 1-9, characterized in that, include: The substrate is laid in layers from bottom to top: base fiberboard, first mesh substrate, stress-absorbing layer, second mesh substrate, and carbonized wood surface layer. The thickness of the carbonized wood surface layer is 2-4 mm; The first and second mesh-like substrates are both mesh structures made of nickel-chromium alloy, with a mesh aperture of 2-5 mm and a wire diameter of 0.3-0.6 mm. The stress-absorbing layer is a polyurethane elastomer layer with a thickness of 1-2 mm; The base fiberboard is a high-density fiberboard with a thickness of 8-12 mm.

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