A method for manufacturing a dimensionally stable large-piece thin OSB composite floor

Abstract

The application discloses a kind of size stable large piece thin OSB composite floor manufacturing method, comprising: surface layer flake and core layer flake are glued after using composite adhesive, and hot-pressing is formed OSB core layer;OSB core layer surface is treated by plasma, and is pasted GF / TPU interlaced layer on both sides of OSB core layer;Real wood surface layer and bottom layer are embedded CNT / PE conductive film, and are stacked with OSB core layer through orthogonal direction, middle clamping GF / TPU buffer layer, interlayer is bonded using high permeability adhesive, and hot-pressing is carried out in stages, and form plate;The micro-camber of plate two ends is pre-processed, and self-repairing sealant microcapsule is embedded in joint chamfer groove;Nanometer hydrophobic layer is generated on the surface of plate surface by chemical vapor deposition, and is coated UV wear-resistant coating;Plate is rolled and solidified, and floor is formed.The application solves the problems of poor size stability, easy deformation, insufficient bending stiffness and joint adhesive layer easy failure of OSB composite floor in the prior art.

Description

Technical Field

[0001] This invention relates to the technical field of layered products, and more particularly to a method for manufacturing a dimensionally stable large-sheet thin OSB composite floor. Background Technology

[0002] OSB composite flooring, or Oriented Strand Board, is a new type of composite structural material made by gluing oriented strand board (OSB) to decorative veneer and other materials. It is a multi-layered structural board made from wood shavings of a specific geometric shape through processes such as drying, gluing, oriented laying, and hot pressing. The surface layer shavings are oriented along the length or width of the board, while the core layer shavings are arranged laterally, forming a stable three- or multi-layer structure. OSB composite flooring is renowned for its high strength, stability, moisture resistance, and environmental friendliness, and is widely used in the construction and decoration industries, including structural materials for flooring, walls, and roofs, as well as furniture manufacturing and packaging.

[0003] Existing technologies for manufacturing OSB composite flooring primarily utilize oriented strand board (OSB), decorative veneer, and adhesives. OSB serves as the substrate, made from small-diameter timber, fast-growing thinnings, etc., shavings of a specific geometric shape, which are then dried, glued, oriented, and hot-pressed. Decorative veneer enhances the flooring's aesthetics. Adhesives typically employ isocyanate resin (MDI), which releases no formaldehyde.

[0004] Existing OSB composite flooring suffers from significant deficiencies in dimensional stability and poor thickness stability, making it prone to deformation during use. This is primarily due to the varying sizes of wood shavings. During hot pressing, these sized shavings experience different degrees of pressure and shrinkage rates, resulting in uneven stress distribution within the board and affecting thickness stability. Furthermore, uneven shaving direction and angle during installation cause variations in the board's mechanical properties across different directions. When environmental humidity and temperature change, the expansion and contraction rates in different directions differ, leading to deformation and reducing the flooring's lifespan and user experience.

[0005] Therefore, it is necessary to improve the existing method for manufacturing dimensionally stable large-sheet thin OSB composite flooring to solve the above problems. Summary of the Invention

[0006] This invention overcomes the shortcomings of the prior art and provides a method for manufacturing large-sheet thin OSB composite flooring with dimensional stability, aiming to solve the problems of poor dimensional stability, easy deformation, insufficient bending stiffness and easy failure of adhesive layer at joints in the prior art.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a method for manufacturing dimensionally stable large-sheet thin OSB composite flooring, comprising:

[0008] S1. Nanocellulose is incorporated into the surface shavings and arranged longitudinally. The core shavings are arranged laterally in an alternating wide and narrow layout. The surface shavings and core shavings are glued together with a composite adhesive and then hot-pressed to form an OSB core layer.

[0009] S2. Plasma treatment is performed on the surface of the OSB core layer, and GF / TPU interwoven layers are laminated on both sides of the OSB core layer.

[0010] S3. Embed CNT / PE conductive film into the surface and bottom layers of solid wood, and stack it with OSB core layer in an orthogonal direction. Insert GF / TPU buffer layer in the middle, and use high-penetration adhesive to bond the layers together. Perform hot pressing in stages to form the board.

[0011] S4. Pre-process the two ends of the board with a slight arch, and pre-embed self-healing sealant microcapsules in the chamfer groove of the joint;

[0012] S5. A nano-hydrophobic layer is generated on the surface of the board through chemical vapor deposition, and a UV wear-resistant coating is applied.

[0013] S6. Roller-curing the board material to form flooring.

[0014] In a preferred embodiment of the present invention, in step S1, the surface shavings are 30-50 mm long, 3-5 mm wide, and 0.3 mm thick; the amount of nanocellulose incorporated is 3%-5% of the mass of the surface shavings, and the nanocellulose has a diameter of 20-50 nm and a length of 1-2 μm.

[0015] In a preferred embodiment of the present invention, the core layer planers adopt an alternating wide and narrow layout, with the wide planers having a width of 8-12mm, the narrow planers having a width of 3-5mm, and a thickness of 0.3-0.5mm, and are arranged laterally in an alternating structure of wide planers-narrow planers-wide planers.

[0016] In a preferred embodiment of the present invention, the plasma treatment in step S2 uses a mixture of argon and oxygen in a volume ratio of 7:3, a radio frequency power of 30-50W, and a treatment time of 40-120 seconds.

[0017] In a preferred embodiment of the present invention, the mass ratio of glass fiber to thermoplastic polyurethane in the GF / TPU interwoven layer is 1.3-1.7:1, the melting temperature is 180-200℃, the film thickness is 0.3-0.5mm, and a mesh structure with a pore size of 2mm×2mm is formed by hot pressing.

[0018] In a preferred embodiment of the present invention, in step S3, the mass ratio of carbon nanotubes to polyethylene in the CNT / PE conductive film is 1.5-2.5:100, the thickness of the conductive film is 0.1-0.2 mm, and the surface resistivity is 10⁻⁶. 3 -105 Ω / sq.

[0019] In a preferred embodiment of the present invention, the radius of curvature of the pre-processed micro-arch in step S4 is 35-45m, the arch height is 0.15-0.25mm / m, the groove depth of the chamfer groove is 1.2-1.8mm, and the groove width is 2.0-2.5mm.

[0020] In a preferred embodiment of the present invention, the nano-hydrophobic layer in step S5 is generated by plasma-enhanced chemical vapor deposition, the volume ratio of hexamethyldisiloxane to carbon tetrafluoride is 1:1.5-2, the deposition temperature is 80-100℃, and the thickness of the hydrophobic layer is 200-300nm.

[0021] In a preferred embodiment of the present invention, the roll pressing curing in step S6 includes a preheating roller temperature of 80-100℃ and a pressure of 0.3-0.5MPa, a main pressing roller temperature of 120-130℃ and a pressure of 1.2-1.5MPa, a setting roller temperature of 60-70℃ and a pressure of 0.8-1.0MPa, and a cooling rate of 15℃ / min.

[0022] In a preferred embodiment of the present invention, the glass fiber and polyether-type TPU in the GF / TPU buffer layer are mixed evenly at a mass ratio of 1:1.2-1.5, heated to 180-200℃ to melt, and the film thickness is 0.2-0.3 mm.

[0023] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0024] (1) This invention discloses a method for manufacturing dimensionally stable large-sheet thin OSB composite flooring. The method involves incorporating nanocellulose into the surface layer of shavings and arranging them longitudinally, while the core layer shavings are arranged transversely with alternating wide and narrow widths. A composite adhesive is used for hot pressing to form the OSB core layer. The surface of the OSB core layer is then plasma-treated and bonded with a GF / TPU interwoven layer. CNT / PE conductive films are embedded in the solid wood surface and bottom layers, stacked orthogonally with the OSB core layer, with a GF / TPU buffer layer added in between. A high-penetration adhesive is used for staged hot pressing to form the board. The ends of the board are pre-processed with a slight arch, and self-healing sealant microcapsules are pre-embedded in the chamfered grooves. A nano-hydrophobic layer is generated through chemical vapor deposition and coated with a UV-resistant wear-resistant coating. Finally, roll pressing and curing are performed to form the flooring. This method effectively solves the problems of poor dimensional stability, easy deformation, insufficient bending stiffness, and easy failure of the adhesive layer at the joints in existing OSB composite flooring technologies. It significantly improves the dimensional stability, bending performance, moisture resistance, antistatic performance, and joint strength of the flooring, extending its service life. It is particularly suitable for large-size installation scenarios.

[0025] (2) This invention significantly improves the activity and wettability of the OSB core layer surface through plasma treatment, enhancing the interfacial bonding force between the GF / TPU interwoven layer and the core layer. The GF / TPU interwoven layer disperses hygrothermal stress through its grid structure, reducing interlayer shear deformation. The rigidity of GF provides mechanical support, while the flexibility of TPU allows for a certain degree of stress release, thereby reducing warpage. The combination of these two factors effectively suppresses interlayer shear deformation and warpage, while the grid structure of the GF / TPU interwoven layer provides additional mechanical interlocking force, further enhancing joint strength. Compared with existing technologies, this invention further improves the dimensional stability and joint strength of the flooring.

[0026] (3) The solid wood surface layer and bottom layer of this invention are stacked orthogonally with the OSB core layer, which offsets the inherent anisotropic expansion of wood and reduces the overall planar expansion difference of the board. The GF / TPU buffer layer sandwiched in between absorbs some stress through its flexibility, especially during thermal expansion and moisture expansion, effectively dispersing stress and preventing warping. The combination of the two not only compensates for the stiffness loss of the thin OSB core layer, but also significantly improves the structural stability and bending resistance of the board. Compared with the prior art, it further improves the bending stiffness and dimensional stability of the flooring.

[0027] (4) This invention incorporates nanocellulose into the surface layer shavings and arranges them longitudinally to construct a three-dimensional network reinforcement structure, significantly improving the flexural modulus and creep resistance of the surface layer. The core layer shavings are arranged laterally with alternating wide and narrow shavings. The wide shavings serve as the main load-bearing units, providing longitudinal flexural strength, while the narrow shavings act as a flexible transition layer to fill gaps and disperse hygrothermal stress. The combination of these two elements not only enhances the strength and stability of the OSB core layer but also effectively reduces the internal stress gradient, providing a highly stable and low-expansion substrate support for the subsequent composite structure. Compared with existing technologies, this further improves the dimensional stability and deformation resistance of the flooring.

[0028] (5) The micro-arch design pre-processed at both ends of the board in this invention provides the board with pre-stored deformation space, preferentially releasing elastic strain during temperature and humidity fluctuations, thus reducing the peak tensile stress in the joint area. The self-healing sealant microcapsules pre-embedded in the joint chamfer groove automatically release polyurethane prepolymer when the joint cracks, reacting with moisture in the environment to generate an elastomer and repair the crack. The combination of these two elements effectively compensates for thermal expansion and contraction deformation during use, prevents the accumulation of gradient strain, and extends the service life of the flooring. Compared with existing technologies, this further improves the long-term stability of the flooring in large-size installation scenarios. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a flowchart of a preferred embodiment of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0033] Application Overview:

[0034] The existing manufacturing technology for dimensionally stable, large-sheet thin OSB composite flooring has two major defects: 1. The thinning process significantly reduces the thickness of the board, resulting in a cubic decrease in bending stiffness. This is because bending stiffness is cubically correlated with thickness. When the ambient temperature and humidity fluctuate, the mismatch in the hygrothermal expansion coefficients between the core layer and the surface layer due to the heterogeneous materials generates interlaminar shear stress. When this stress exceeds the interfacial bonding strength, uneven expansion occurs, inducing asymmetric bidirectional warping. 2. In large-size installation scenarios, the inherent anisotropic hygroscopic expansion characteristics of OSB oriented strands will form a multidimensional stress field within the board plane. Small deformations will be continuously transmitted over long distances, resulting in gradient strain accumulation. Ultimately, tensile stress concentration will form in the joint constraint area, causing the adhesive layer at the joint to undergo brittle-ductile transition failure, ultimately leading to significant warping or joint cracking.

[0035] To address the aforementioned issues, this application proposes a method for manufacturing dimensionally stable, large-sheet, thin OSB composite flooring. This method constructs a composite buffer system consisting of a GF / TPU interwoven layer, a GF / TPU buffer layer, and a GF / TPU conductive film. A dynamic balance of multidimensional expansion coefficients is achieved through an orthogonal stacking structure. The GF / TPU mesh layer forms a three-dimensional interlocking interface through mechanical interlocking and melt penetration. The CNT / PE conductive film utilizes the negative expansion characteristics of carbon nanotubes to counteract wood swelling due to moisture. The orthogonal stacking directionality inhibits anisotropic strain transmission. Furthermore, a pre-set micro-arching and self-healing microcapsule joint protection system blocks gradient strain accumulation through deformation pre-compensation and stress self-release mechanisms.

[0036] Exemplary method:

[0037] like Figure 1 As shown, a method for manufacturing a dimensionally stable large-sheet thin OSB composite floor includes the following steps:

[0038] S1. Nanocellulose is incorporated into the surface shavings and arranged longitudinally. The core shavings are arranged laterally in an alternating wide and narrow layout. The surface shavings and core shavings are glued together with a composite adhesive and then hot-pressed to form an OSB core layer.

[0039] S2. Plasma treatment is performed on the surface of the OSB core layer, and GF / TPU interwoven layers are laminated on both sides of the OSB core layer.

[0040] S3. Embed CNT / PE conductive film into the surface and bottom layers of solid wood, and stack it with OSB core layer in an orthogonal direction. Insert GF / TPU buffer layer in the middle, and use high-penetration adhesive to bond the layers together. Perform hot pressing in stages to form the board.

[0041] S4. Pre-process the two ends of the board with a slight arch, and pre-embed self-healing sealant microcapsules in the chamfer groove of the joint;

[0042] S5. A nano-hydrophobic layer is generated on the surface of the board through chemical vapor deposition, and a UV wear-resistant coating is applied.

[0043] S6. Roller-curing the board material to form flooring.

[0044] Wood chips are the core raw material for OSB manufacturing. They are made by cutting wood into long, thin strips using a chipper. Fast-growing wood is used, specifically poplar and pine. The surface chips are made primarily from high-quality fast-growing poplar, which has fine, long fibers and moderate density, providing superior longitudinal bending strength. The core chips are a blend of pine and poplar. The resin content of pine enhances the natural moisture resistance of the board, and all the wood has been matured for more than 20 years to ensure the stability of the lignin and cellulose structure.

[0045] In step S1, the surface shavings are 30-50 mm long, 3-5 mm wide, and 0.3 mm thick; 3%-5% nanocellulose is added to a water-soluble epoxy resin with a solid content of 60% and a viscosity of 800 mPa·s; high-speed rotary mixing is performed at 2500-3000 rpm for 15-20 min to form a uniform dispersion; the nanocellulose has a diameter of 20-50 nm, a length of 1-2 μm, and a specific surface area of ​​300 m². 2 / g, can form a three-dimensional network reinforcement structure;

[0046] The surface shavings are immersed in the dispersion at a pressure of 0.6 MPa for 2-5 minutes to ensure that the nanocellulose enters the pores of the surface shavings and forms a continuous reinforcing phase inside the shavings. The immersed surface shavings are then arranged longitudinally with the wood fiber direction aligned with the length of the board.

[0047] In the core layer shavings, the wide shavings are 8-12mm wide, the narrow shavings are 3-5mm wide, and the thickness is 0.3-0.5mm. The core layer shavings are arranged in an alternating structure of wide shavings-narrow shavings-wide shavings, and the direction of the wood fibers in the core layer shavings is consistent with the width of the board. The wide shavings serve as the main load-bearing units and are arranged continuously along the width of the board to provide longitudinal bending strength, while the narrow shavings serve as a flexible transition layer to fill the gaps between the wide shavings.

[0048] In step S1, a composite adhesive is prepared by blending MDI adhesive and polyvinyl alcohol (PVA) at a ratio of 7:3, with an application rate of 200-220 g / m³. 2 ;

[0049] The arranged surface and core slices are segmented and hot-pressed to form the OSB core layer:

[0050] Preheating stage: The temperature rises from room temperature to 120℃ in 90-120 seconds, with a pressure gradient of 0.5MPa / 10 seconds;

[0051] Curing stage: Temperature 135℃-140℃, pressure 2.0MPa, time 300-450 seconds;

[0052] Cooling stage: Water-cooled templates are used with a cooling rate of 30℃ / minute to avoid stress concentration.

[0053] Step S1 involves constructing a three-dimensional network reinforcement phase within the surface shavings using nanocellulose, thereby enhancing flexural modulus and creep resistance. The alternating wide and narrow core layer layout effectively disperses hygrothermal stress through the synergistic effect of rigid wide sheets bearing load and flexible narrow sheets absorbing energy. Combined with a segmented temperature-controlled hot pressing process, this reduces the internal stress gradient, providing a highly stable and low-expansion substrate support for the subsequent composite structure.

[0054] In step S2, a 7:3 argon / oxygen mixed gas radio frequency plasma is used with a power of 30-50W and a treatment time of 40-120 seconds to increase the oxygen content on the surface of the OSB core layer, increase the content of surface active groups -OH and -COOH, reduce the wetting angle, and enhance the bonding force of the adhesive interface. After plasma treatment, the surface is left to stand for 30 minutes at 20℃ and 50% RH to avoid the decay of active groups.

[0055] In step S2, the GF / TPU interwoven layer is prepared:

[0056] Alkali-free short-cut glass fiber (GF) with a diameter of 10-15μm and a length of 3-5mm is selected. The surface is treated with silane coupling agent to enhance the interfacial bonding force with thermoplastic polyurethane (TPU).

[0057] Thermoplastic polyurethane is selected from polyester-type TPU particles with a hardness of 80-85 Shore A.

[0058] GF and TPU are mixed uniformly at a mass ratio of 1.3-1.7:1 and heated to 180-200℃ to melt, forming a uniform GF / TPU melt mixture. The GF / TPU melt mixture is extruded into a film with a thickness of 0.3-0.5mm and rapidly cooled and shaped by calendering rollers. The GF / TPU interwoven layer after film formation is then hot-pressed into a grid with a pore size of 2mm×2mm, a temperature of 160-180℃, a pressure of 0.5-1.0MPa, and a pressing time of 3-5 minutes. The grid depth accounts for 40-60% of the film thickness, improving the interlayer mechanical interlocking ability.

[0059] The GF / TPU interwoven layer is laid flat on the surface of the OSB core layer and hot-pressed at 160℃ with a pressure of 0.8MPa for 8-10 minutes. At this time, the TPU melts and penetrates into the pores of the OSB surface.

[0060] Step S2 significantly enhances the activity and wettability of the OSB core layer surface through plasma treatment, strengthening the interfacial bonding between the GF / TPU interwoven layer and the core layer. Simultaneously, the grid structure of the GF / TPU interwoven layer disperses hygrothermal stress, effectively suppressing interlayer shear deformation and warping. Building upon this, Step S3 further optimizes the electrostatic dissipation performance and overall structural stability of the board through the embedding of a CNT / PE conductive film and an orthogonal stacking design, providing comprehensive assurance for the dimensional stability and functionality of the composite flooring in high-end applications.

[0061] In step S3, solid wood is selected to wrap the OSB core layer; the fiber direction of the solid wood surface layer is orthogonally stacked with the core layer, and the inherent anisotropic expansion of wood is offset by orthogonal constraint, which reduces the difference in planar expansion of the whole board. In addition, the bending modulus of solid wood is significantly higher than that of pure OSB core layer, which can compensate for the stiffness loss of thin OSB core layer.

[0062] In step S3, carbon nanotubes (CNTs) and polyethylene (PE) are melt-blended at a mass ratio of 1.5-2.5:100 to prepare a CNT / PE conductive film with a thickness of 0.1-0.2 mm and a surface resistivity of 10⁻⁶. 3 -10 5 Ω / sq;

[0063] After microwave drying the surface and bottom layers of solid wood to a moisture content of ≤6%, grooves are cut into the inner surface of the wood. The grooves are 0.15-0.25mm deep, 0.3-0.5mm wide, and 5-8mm apart. The CNT / PE conductive film is then embedded into the grooves by roller pressing at a temperature of 90-110℃ and a pressure of 0.3-0.5MPa, so that the conductive film and the wood form a mechanical interlocking structure.

[0064] The solid wood surface and bottom layers with embedded conductive films are placed on the upper and lower sides of the OSB core layer, respectively, and a GF / TPU buffer layer is added in the middle to form a symmetrical structure.

[0065] In step S3, the GF / TPU buffer layer is prepared:

[0066] Alkali-free chopped glass fiber (GF) with a diameter of 10-15 μm and a length of 3-5 mm is selected. The surface is treated with a silane coupling agent to enhance the interfacial bonding with polyether-type TPU.

[0067] The resilience of polyether-type TPU is improved compared to that of S2 thermoplastic polyurethane, and its coefficient of thermal expansion matches that of CNT / PE conductive film.

[0068] Mix GF and TPU evenly at a mass ratio of 1:1.2-1.5. Compared with the interwoven layer, reduce the proportion of GF to improve the flexibility of the buffer layer. Heat to 180-200℃ to melt and form a uniform GF / TPU mixed melt. Extrude the GF / TPU mixed melt into a uniform and dense film with a thickness of 0.2-0.3mm.

[0069] GF / TPU is laid flat on one side of the CNT / PE conductive film on the surface and bottom of the solid wood. The hot pressing temperature is reduced to 130-140℃, the pressure is 0.5-0.8MPa, and the time is 5-7 minutes, so that the TPU is partially melted to form a viscoelastic interface.

[0070] The high-penetration adhesive between layers is a 6:4 blend of bisphenol A type epoxy resin and polyurethane prepolymer, with a viscosity of 300-500 mPa·s and an application rate of 150-180 g / m³. 2 ;

[0071] The glued wood is then subjected to staged hot pressing:

[0072] Preheating and penetration stage: temperature is 80℃-120℃, heating rate is 0.3℃ / s, pressure increases linearly from 0.5MPa to 1.0MPa, duration is 120-180s; at this time, the adhesive initially melts.

[0073] Medium-temperature main pressure stage: temperature is 140℃-150℃, constant temperature control, pressure is 2.5-3.0MPa, duration is 300-400s; at this time, the negative expansion effect of CNT / PE conductive film is triggered to counteract the wood swelling strain, the adhesive initially crosslinks, the interface shear is enhanced, and the TPU in the GF / TPU buffer layer partially melts and penetrates into the wood pores.

[0074] High-temperature activation stage: The temperature is 150℃-165℃, the pressure is 1.5-2.0MPa, and the pressure is gradually reduced by 0.05MPa / s based on the medium-temperature main pressure stage, with a duration of 120-180s; at this time, the adhesive undergoes secondary cross-linking, and the negative expansion of the CNT / PE conductive film is strengthened.

[0075] Cooling stage: The first stage has a cooling rate of 5℃ / min, with the pressure maintained at 1.0MPa, cooling down to 100℃; the second stage has a cooling rate of 10℃ / min, with the pressure reduced to 0.5MPa, cooling down to 60℃; the cooling time is 20-25min, releasing the thermal expansion difference between the core layer and the surface layer through slow cooling.

[0076] Step S3, through the embedding of CNT / PE conductive films and orthogonal stacking design, utilizes the negative expansion characteristics of carbon nanotubes to counteract the moisture swelling of wood, significantly improving the electrostatic dissipation performance and structural stability of the board. The orthogonal stacking directionality effectively suppresses anisotropic strain transmission, reducing the overall planar expansion difference of the board and compensating for the stiffness loss of the thin OSB core layer. Building on this, step S4, through pre-processing micro-camber and pre-embedding of self-healing sealant microcapsules, further blocks the accumulation of gradient strain, ensuring the long-term stability of the composite flooring in large-size installation scenarios.

[0077] In step S4, the two ends of the board are processed into a pre-set micro-arched structure with an arch curvature radius R = 35-45m and an arch height h = 0.15-0.25mm / m to compensate for thermal expansion and contraction deformation during use. The micro-arched design gives the board a pre-stored deformation space, and releases elastic strain first when temperature and humidity fluctuate, thereby reducing the peak tensile stress in the joint area.

[0078] A V-shaped chamfer groove is machined on the butt joint side of the plate. The groove depth is 1.2-1.8mm, the groove width is 2.0-2.5mm, the bottom fillet radius R = 0.3-0.5mm, and the chamfer angle is 45-60°.

[0079] The shell material of the self-healing microcapsule is urea-formaldehyde resin, and the core material is isocyanate-terminated polyurethane prepolymer.

[0080] Polyurethane-based self-healing sealant microcapsules were pre-embedded in chamfered grooves by spraying. The microcapsule particle size was 50-80 μm, the shell thickness was 2-3 μm, and the loading was 15-20 g / m³. 2 After spraying, infrared radiation is used for curing for 30-60 seconds to allow the microcapsules to physically adhere to the tank wall.

[0081] When the crack width at the joint is ≥0.1mm, the microcapsules rupture to release the prepolymer, which reacts with moisture in the environment to generate polyurethane elastomer, repairing the crack within 24 hours.

[0082] Step S4, through pre-processing the micro-arch and embedding self-healing sealant microcapsules, effectively compensates for thermal expansion and contraction deformation during use, reduces the peak tensile stress in the joint area, and extends the service life of the floor by utilizing the self-healing microcapsules' automatic repair capability when joints crack. Building on this, step S5 further enhances the floor's waterproof and wear-resistant properties by generating a nano-hydrophobic layer through chemical vapor deposition and applying a UV-resistant abrasion-resistant coating, ensuring its stability during long-term use.

[0083] In step S5, a fluorocarbon nanocone array hydrophobic layer is generated on the surface of the substrate using plasma-enhanced chemical vapor deposition.

[0084] Hexamethyldisiloxane and carbon tetrafluoride were mixed at a volume ratio of 1:1.5-2; deposition was carried out at a vacuum of 10-20 Pa, an RF power of 100-150 W, a deposition temperature of 80-100 °C, and a deposition time of 30-45 min; the hydrophobic layer thickness was 200-300 nm.

[0085] In step S5, a nano-alumina-reinforced UV-curable coating is applied using a roller coating process. The UV abrasion-resistant coating is formulated with 95% acrylate UV resin, 10-15% nano-alumina, and 2-3% photoinitiator. The thickness of the UV abrasion-resistant coating is 50-80 μm, the roller coating speed is 2-3 m / min, and it is cured by ultraviolet light irradiation at a curing energy of 800-1000 mJ / cm. 2 .

[0086] In step S6, the curing is performed by a three-roll continuous roller press;

[0087] The temperature of the preheating roller is 80-100℃ and the pressure is 0.3-0.5MPa, used to eliminate air bubbles in the coating;

[0088] The temperature of the main pressure roller is 120-130℃ and the pressure is 1.2-1.5MPa, which is used to promote the formation of chemical bonds between the UV coating and the hydrophobic layer;

[0089] The temperature of the shaping roller is 60-70℃, the pressure is 0.8-1.0MPa, and the cooling rate is 15℃ / min. It is used to lock the flatness of the board.

[0090] After roll pressing, the sheet material is placed in a constant temperature and humidity chamber and left to stand for 48-72 hours to allow residual stress to be released evenly.

[0091] Example 1:

[0092] A method for manufacturing dimensionally stable large-sheet thin OSB composite flooring includes:

[0093] Materials preparation:

[0094] The surface shavings are made from high-quality fast-growing poplar wood with fine, long fibers and moderate density.

[0095] The core layer of shavings is made from a mixture of pine and poplar wood, with the resin content of the pine enhancing the natural moisture resistance of the board.

[0096] Nanocellulose has a diameter of 20-50 nm, a length of 1-2 μm, and a specific surface area of ​​300 m². 2 / g.

[0097] The composite adhesive is made by compounding MDI adhesive with polyvinyl alcohol (PVA) in a 7:3 ratio.

[0098] The GF / TPU interwoven layer is made of alkali-free chopped glass fibers (GF) with a diameter of 10-15μm and a length of 3-5mm; the thermoplastic polyurethane (TPU) has a hardness of 80-85 Shore A.

[0099] CNT / PE conductive film: carbon nanotubes (CNTs) to polyethylene (PE) mass ratio 2:100, thickness 0.1-0.2 mm, surface resistivity 10. 3 -10 5 Ω / sq.

[0100] Self-healing microcapsules: the shell material is urea-formaldehyde resin, the core material is isocyanate-terminated polyurethane prepolymer, the particle size is 50-80μm, and the shell thickness is 2-3μm.

[0101] S1 and OSB core layer preparation:

[0102] The surface shavings are 40 mm long, 4 mm wide, and 0.3 mm thick. 4% nanocellulose is added to water-soluble epoxy resin (60% solid content, 800 mPa·s viscosity), and mixed at high speed (2800 rpm, 18 min) to form a uniform dispersion. The surface shavings are then immersed in the dispersion at a pressure of 0.6 MPa for 3 min to ensure the nanocellulose penetrates the pores of the surface shavings. The impregnated surface shavings are then arranged longitudinally, with the wood fiber direction aligned with the length of the board.

[0103] Wide planers are 10mm wide, narrow planers are 4mm wide, and 0.4mm thick; they are arranged in an alternating pattern of wide planers-narrow planers-wide planers, with the wood fiber direction consistent with the width of the board;

[0104] Preheating stage: Temperature rises from room temperature to 120℃ over 100 seconds, with a pressure gradient of 0.5 MPa / 10 seconds.

[0105] Curing stage: temperature 135℃, pressure 2.0MPa, time 360 ​​seconds;

[0106] Cooling stage: Water-cooled templates are used, with a cooling rate of 30℃ / minute.

[0107] S2, GF / TPU interwoven layer bonding

[0108] A 7:3 argon / oxygen gas mixture was used, with a radio frequency power of 40W and a processing time of 80 seconds; after processing, the mixture was left to stand for 30 minutes at 20℃ and 50% RH.

[0109] GF and TPU are mixed at a mass ratio of 1.5:1, heated to 190℃ to melt, and extruded into a film with a thickness of 0.4mm. Hot-pressing mesh formation is then performed with a pore size of 2mm×2mm, a temperature of 170℃, a pressure of 0.8MPa, a pressing time of 4 minutes, and a mesh depth of 50% of the film thickness. The GF / TPU interwoven layer is then laid flat on the surface of the OSB core layer and hot-pressed at 160℃ with a pressure of 0.8MPa for 9 minutes.

[0110] S3, embedded CNT / PE conductive film, buffer layer and hot pressing;

[0111] The solid wood surface and bottom layer are microwave dried to a moisture content of 6%; grooves are made on the inner surface: groove depth 0.2mm, groove width 0.4mm, and spacing 6mm; carbon nanotubes (CNT) and polyethylene (PE) are mixed at a mass ratio of 2:100, and the CNT / PE conductive film is embedded in the groove by roller pressing at a temperature of 100℃ and a pressure of 0.4MPa.

[0112] Preparation of GF / TPU buffer layer: Alkali-free short-cut glass fiber GF and polyether-type TPU were selected;

[0113] GF and TPU were mixed uniformly at a mass ratio of 1:1.4. Compared with the interwoven layer, the proportion of GF was reduced to improve the flexibility of the buffer layer. The mixture was heated to 180-200℃ to melt, forming a uniform GF / TPU melt. The GF / TPU melt was extruded into a uniform and dense film with a thickness of 0.2-0.3mm. GF / TPU was laid flat on one side of the CNT / PE conductive film on the surface and bottom of the solid wood. The hot-pressing temperature was reduced to 140℃, the pressure was 0.6MPa, and the time was 6 minutes. The high-penetration adhesive between the layers was a 6:4 blend of bisphenol A epoxy resin and polyurethane prepolymer, with a viscosity of 400mPa·s and an application rate of 160g / m³.2 ;

[0114] Hot pressing parameters:

[0115] Preheating and infiltration stage: temperature 100℃, heating rate 0.3℃ / s, pressure linearly increasing from 0.5MPa to 1.0MPa, time 150 seconds; Intermediate temperature main pressure stage: temperature 145℃, pressure 2.8MPa, time 360 ​​seconds; High temperature activation stage: temperature 160℃, pressure 1.8MPa, gradient pressure reduction rate 0.05MPa / s, time 150 seconds; Cooling stage: first stage cooling rate 5℃ / min, pressure 1.0MPa, cooling to 100℃; second stage cooling rate 10℃ / min, pressure 0.5MPa, cooling to 60℃.

[0116] S4. Micro-arching processing, arch curvature radius R = 40m, arch height h = 0.2mm / m; spray polyurethane-based self-healing sealant microcapsules into the V-shaped chamfered groove, with a load of 18g / m. 2 Infrared radiation curing for 45 seconds.

[0117] S5. Hydrophobic layer deposition: hexamethyldisiloxane to carbon tetrafluoride volume ratio 1:1.8; vacuum degree 15 Pa, RF power 120 W, deposition temperature 90℃, time 35 min, hydrophobic layer thickness 250 nm; abrasion-resistant coating application: roller coating speed 2.5 m / min, coating thickness 60 μm, curing energy 900 mJ / cm². 2 .

[0118] S6, Roller Curing:

[0119] Preheating roller: temperature 90℃, pressure 0.4MPa;

[0120] Main pressure roller: temperature 125℃, pressure 1.3MPa;

[0121] Setting roller: temperature 65℃, pressure 0.9MPa, cooling rate 15℃ / min;

[0122] After rolling, the sheet material is placed in a constant temperature and humidity chamber (20℃, RH50%) and left to stand for 60 hours.

[0123] Example 2:

[0124] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 1 and will not be repeated here. The difference between this example and Example 1 is that...

[0125] The ratio of GF to TPU in the GF / TPU interwoven layer is 1.4:1.

[0126] Example 3:

[0127] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 1 and will not be repeated here. The difference between this example and Example 1 is that...

[0128] The ratio of GF to TPU in the GF / TPU interwoven layer is 1.6:1.

[0129] Example 4:

[0130] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 1 and will not be repeated here. The difference between this example and Example 1 is that...

[0131] The ratio of GF to TPU in the GF / TPU buffer layer is 1:1.3.

[0132] Example 5:

[0133] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 1 and will not be repeated here. The difference between this example and Example 1 is that...

[0134] The ratio of GF to TPU in the GF / TPU buffer layer is 1:1.2.

[0135] Example 6:

[0136] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 1 and will not be repeated here. The difference between this example and Example 1 is that...

[0137] The ratio of GF to TPU in the GF / TPU buffer layer is 1:1.5.

[0138] Example 7:

[0139] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 2 and will not be repeated here. The difference between this example and Example 2 is that...

[0140] The ratio of GF to TPU in the GF / TPU buffer layer is 1:1.3.

[0141] Example 8:

[0142] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that in Example 3, and will not be repeated here. The difference between this example and Example 3 is that...

[0143] The ratio of GF to TPU in the GF / TPU buffer layer is 1:1.3.

[0144] Example 9:

[0145] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 2 and will not be repeated here. The difference between this example and Example 2 is that...

[0146] The ratio of GF to TPU in the GF / TPU buffer layer is 1:1.2.

[0147] Example 10:

[0148] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that in Example 3, and will not be repeated here. The difference between this example and Example 3 is that...

[0149] The ratio of GF to TPU in the GF / TPU buffer layer is 1:1.2.

[0150] Example 11:

[0151] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 2 and will not be repeated here. The difference between this example and Example 2 is that...

[0152] The ratio of GF to TPU in the GF / TPU buffer layer is 1:1.5.

[0153] Example 12:

[0154] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that in Example 3, and will not be repeated here. The difference between this example and Example 3 is that...

[0155] The ratio of GF to TPU in the GF / TPU buffer layer is 1:1.5.

[0156] Example 13:

[0157] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 1 and will not be repeated here. The difference between this example and Example 1 is that...

[0158] The CNT / PE conductive film contains carbon nanotubes (CNTs) and polyethylene (PE) in a mass ratio of 1.5:100.

[0159] Example 14:

[0160] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 1 and will not be repeated here. The difference between this example and Example 1 is that...

[0161] The CNT / PE conductive film contains carbon nanotubes (CNTs) and polyethylene (PE) in a mass ratio of 1.7:100.

[0162] Example 15:

[0163] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 1 and will not be repeated here. The difference between this example and Example 1 is that...

[0164] The CNT / PE conductive film contains carbon nanotubes (CNTs) and polyethylene (PE) in a mass ratio of 2.5:100.

[0165] Example 16:

[0166] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 1 and will not be repeated here. The difference between this example and Example 1 is that...

[0167] The CNT / PE conductive film contains carbon nanotubes (CNTs) and polyethylene (PE) in a mass ratio of 2.3:100.

[0168] Comparative Example 1:

[0169] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 1 and will not be repeated here. The difference between this example and Example 1 is that...

[0170] No GF / TPU interleaving layer is set.

[0171] Comparative Example 2:

[0172] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 1 and will not be repeated here. The difference between this example and Example 1 is that...

[0173] No GF / TPU buffer layer is set.

[0174] Comparative Example 3:

[0175] A method for manufacturing a dimensionally stable large-sheet thin OSB composite flooring is similar to that of Example 1 and will not be repeated here. The difference between this example and Example 1 is that...

[0176] No CNT / PE conductive film is installed.

[0177] Experimental Example 1:

[0178] This experiment selected Examples 1 to 12, as well as Comparative Examples 1 and 2, to conduct experiments and test the warping, bending resistance, and joint strength of the flooring.

[0179] Warpage testing shall be conducted in accordance with GB / T 17657, bending performance testing shall be conducted in accordance with GB / T 17657, and joint strength testing shall be conducted in accordance with GB / T 18103.

[0180] Warpage is a key indicator for measuring the dimensional stability of flooring in humid and hot environments, and can effectively assess whether the flooring will deform during use; bending resistance is an important indicator of the load-bearing capacity and stiffness of flooring, and can assess whether the flooring can withstand the expected load during use; joint strength can assess the strength of the adhesive layer at the joints of flooring in large-scale installation scenarios, and prevent joint cracking.

[0181] Table 1. Testing of Warpage, Bending Resistance, and Joint Strength

[0182]

[0183] The results of Experiment 1 show that the warping, flexural strength, and joint strength of the flooring are closely related to the material ratio of the GF / TPU interwoven layer and the buffer layer:

[0184] The GF / TPU interwoven layer disperses hygrothermal stress through its grid structure, reducing interlayer shear deformation. The rigidity of GF provides mechanical support, while the flexibility of TPU allows for a certain degree of stress release, thereby reducing warpage. After being treated with a silane coupling agent, the interfacial bonding between GF and TPU is significantly enhanced. This chemical bonding improves the overall strength and stability of the interwoven layer. The thermoplastic properties of TPU allow it to penetrate into the pores of the OSB core layer during hot pressing, forming chemical bonds and further enhancing the interlayer bonding.

[0185] The GF / TPU buffer layer absorbs some of the stress through its flexibility, especially during thermal expansion and moisture expansion. The flexibility of the buffer layer can effectively disperse stress and prevent warping.

[0186] GF's high modulus significantly improves the flexural strength of the flooring, especially when the proportion of interwoven layers is high. The flexibility of the buffer layer compensates for the brittleness of the rigid material to a certain extent, so that the flooring will not fail due to local stress concentration when subjected to bending loads.

[0187] In addition, the self-healing microcapsules release polyurethane prepolymer when the joint cracks, which reacts with moisture in the environment to generate an elastomer, thereby repairing the crack and enhancing the joint strength. The mesh structure of the interwoven layer provides additional mechanical interlocking force at the joint, further enhancing the joint strength.

[0188] Experimental Example 2:

[0189] This experiment selects Examples 1, 13 to 16, and Comparative Example 3 to conduct experiments and test the antistatic performance of the flooring.

[0190] The antistatic performance test adopts GB / T18103; antistatic performance is an important indicator for evaluating the static dissipation ability of flooring in special scenarios such as data centers, and preventing safety hazards caused by static accumulation.

[0191] Table 2. Tests for warpage, bending resistance, and antistatic properties.

[0192]

[0193]

[0194] The chemical compatibility between CNT and PE determines the stability and conductivity of the conductive film. When the CNT content is moderate, CNT forms a stable chemical bond with the PE matrix, resulting in optimal conductivity. CNT forms a conductive network in the PE matrix, which allows for rapid charge conduction, thereby reducing surface resistivity. As the CNT content increases, the continuity of the conductive network is enhanced, and the surface resistivity is significantly reduced. The negative expansion characteristics of CNT can counteract the swelling effect of wood due to moisture, thus physically reducing the warping and deformation of the flooring.

[0195] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for manufacturing a dimensionally stable large-sheet thin OSB composite floor, characterized in that, Including the following steps: S1. Nanocellulose is incorporated into the surface shavings and arranged longitudinally. The core shavings are arranged laterally in an alternating wide and narrow layout. The surface shavings and core shavings are glued together with a composite adhesive and then hot-pressed to form an OSB core layer. S2. Plasma treatment is performed on the surface of the OSB core layer, and GF / TPU interwoven layers are laminated on both sides of the OSB core layer. S3. Embed CNT / PE conductive film into the surface and bottom layers of solid wood, and stack it with OSB core layer in an orthogonal direction. Insert GF / TPU buffer layer in the middle, and use high-penetration adhesive to bond the layers together. Perform hot pressing in stages to form the board. S4. Pre-process the two ends of the board with a slight arch, and pre-embed self-healing sealant microcapsules in the chamfer groove of the joint; S5. A nano-hydrophobic layer is generated on the surface of the board through chemical vapor deposition, and a UV wear-resistant coating is applied. S6. Roller-curing process is applied to the board to form flooring.

2. The method for manufacturing a dimensionally stable large-sheet thin OSB composite floor according to claim 1, characterized in that: In step S1, the surface shavings are 30-50 mm long, 3-5 mm wide, and 0.3 mm thick; the amount of nanocellulose incorporated is 3%-5% of the mass of the surface shavings, and the nanocellulose has a diameter of 20-50 nm and a length of 1-2 μm.

3. The method for manufacturing a dimensionally stable large-sheet thin OSB composite floor according to claim 1, characterized in that: The core layer planers adopt an alternating wide and narrow layout, with the wide planers being 8-12mm wide and the narrow planers being 3-5mm wide and 0.3-0.5mm thick, and are arranged horizontally in an alternating structure of wide planers-narrow planers-wide planers.

4. The method for manufacturing a dimensionally stable large-sheet thin OSB composite floor according to claim 1, characterized in that: In step S2, the plasma treatment uses a mixture of argon and oxygen in a volume ratio of 7:3, with a radio frequency power of 30-50W and a treatment time of 40-120 seconds.

5. The method for manufacturing a dimensionally stable large-sheet thin OSB composite floor according to claim 1, characterized in that: The GF / TPU interwoven layer has a glass fiber to thermoplastic polyurethane mass ratio of 1.3-1.7:1, a melting temperature of 180-200℃, a film thickness of 0.3-0.5mm, and forms a mesh structure with a pore size of 2mm×2mm through hot pressing.

6. The method for manufacturing a dimensionally stable large-sheet thin OSB composite floor according to claim 1, characterized in that: In step S3, the mass ratio of carbon nanotubes to polyethylene in the CNT / PE conductive film is 1.5-2.5:100, the film thickness is 0.1-0.2 mm, and the surface resistivity is 10⁻⁶. 3 -10 5 Ω / sq.

7. The method for manufacturing a dimensionally stable large-sheet thin OSB composite floor according to claim 1, characterized in that: In step S4, the pre-processed micro-arch radius of curvature is 35-45m, the arch height is 0.15-0.25mm / m, the groove depth of the joint chamfer groove is 1.2-1.8mm, and the groove width is 2.0-2.5mm.

8. The method for manufacturing a dimensionally stable large-sheet thin OSB composite floor according to claim 1, characterized in that: In step S5, the nano-hydrophobic layer is generated by plasma-enhanced chemical vapor deposition, with a volume ratio of hexamethyldisiloxane to carbon tetrafluoride of 1:1.5-2, a deposition temperature of 80-100℃, and a hydrophobic layer thickness of 200-300nm.

9. The method for manufacturing a dimensionally stable large-sheet thin OSB composite floor according to claim 1, characterized in that: In step S6, the roll pressing curing includes a preheating roller temperature of 80-100℃ and a pressure of 0.3-0.5MPa, a main pressure roller temperature of 120-130℃ and a pressure of 1.2-1.5MPa, a setting roller temperature of 60-70℃ and a pressure of 0.8-1.0MPa, and a cooling rate of 15℃ / min.

10. The method for manufacturing a dimensionally stable large-sheet thin OSB composite floor according to claim 1, characterized in that: The glass fiber and polyether-type TPU in the GF / TPU buffer layer are mixed evenly at a mass ratio of 1:1.2-1.5, heated to 180-200℃ to melt, and the film thickness is 0.2-0.3mm.

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