Manufacturing method of large thin OSB (oriented strand board) composite floor with stable size

Abstract

The invention discloses a method for manufacturing a size-stable large thin OSB (oriented strand board) composite floor, which comprises the following steps of: applying glue to surface flakes and core flakes by using a composite adhesive, and performing hot pressing to form an OSB core layer; the surface of the OSB core layer is subjected to plasma treatment, and GF / TPU interwoven layers are attached to the two faces of the OSB core layer; cNT / PE conductive films are embedded in the surface layer and the bottom layer of the solid wood, the CNT / PE conductive films and the OSB core layer are stacked in the orthogonal direction, a GF / TPU buffer layer is clamped between the CNT / PE conductive films and the OSB core layer, the layers are bonded through a high-permeability adhesive, hot pressing is conducted in stages, and a board is formed; micro cambers are pre-machined at the two ends of the plate, and self-repairing sealant microcapsules are pre-buried in seam chamfering grooves; a nano hydrophobic layer is generated on the surface of the plate through chemical vapor deposition, and a UV wear-resistant coating is coated; and the plate is subjected to rolling curing treatment, and the floor is formed. The OSB composite floor solves the problems that in the prior art, an OSB composite floor is poor in size stability, prone to deformation and insufficient in flexural rigidity, and an adhesive layer at a seam is prone to failure.

Description

Technical Field

[0001] The present invention relates to the technical field of laminated products, and particularly to a manufacturing method for a dimensionally stable large-sized thin OSB composite floor. Background Art

[0002] An OSB composite floor, that is, an oriented strand board, is a new type of composite structural material made by gluing an oriented strand board as a base material with materials such as decorative veneer. It is a multi-layer structural board made from wood chips with specific geometric shapes through processes such as drying, sizing, oriented laying, and hot pressing. The surface chips of this board are oriented along the length or width direction of the board, while the core chips are arranged transversely, forming a stable three-layer or multi-layer structure; the OSB composite floor is known for its high strength, stability, moisture resistance, and environmental protection performance, and is widely used in the construction and decoration industries, including structural materials such as floors, walls, and roofs, as well as fields such as furniture manufacturing and packaging.

[0003] In the prior art for preparing OSB composite floors, the main materials include oriented strand boards, decorative veneer, and adhesives. The oriented strand board, as the base material, is made from small-diameter logs, fast-growing thinned wood, etc. into chips with a certain geometric shape, and is formed through drying, sizing, oriented laying, and hot pressing. Decorative veneer is used to enhance the aesthetics of the floor. Adhesives mostly use isocyanate resin (MDI) and do not release formaldehyde.

[0004] Existing OSB composite floors have obvious deficiencies in dimensional stability, with poor thickness stability and being prone to deformation during use. This is mainly because the sizes of the wood chips are different. During hot pressing, the different-sized wood chips are compressed and shrunk at different degrees, resulting in uneven stress distribution inside the board, thus affecting thickness stability. In addition, the directions and angles of the wood chips are uneven during the laying process, making the mechanical properties of the board different in each direction. When the environmental humidity and temperature change, the expansion and contraction degrees in different directions are inconsistent, thereby causing deformation problems and reducing the service life and user experience of the floor.

[0005] Therefore, it is necessary to improve a manufacturing method for a dimensionally stable large-sized thin OSB composite floor in the prior art to solve the above problems. Summary of the Invention

[0006] The present invention overcomes the deficiencies of the prior art and provides a manufacturing method for a dimensionally stable large-sized thin OSB composite floor, aiming to solve the problems of poor dimensional stability, easy deformation, insufficient flexural rigidity, and easy failure of the adhesive layer at the joints in the prior art.

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

[0008] S1. Incorporate nanocellulose into the surface shavings and arrange them longitudinally. Arrange the core shavings in a wide-narrow alternating layout horizontally. Apply sizing to the surface shavings and core shavings with a composite adhesive and then perform hot pressing to form the OSB core layer;

[0009] S2. Perform plasma treatment on the surface of the OSB core layer, and bond GF / TPU interwoven layers on both sides of the OSB core layer;

[0010] S3. Embed CNT / PE conductive films into the solid wood surface layer and bottom layer, stack them orthogonally with the OSB core layer, sandwich a GF / TPU buffer layer in the middle, use a highly permeable adhesive for bonding between layers, and perform hot pressing in stages to form the board;

[0011] S4. Pre-process a slight camber at both ends of the board, and embed self-healing sealant microcapsules in the seam chamfer groove;

[0012] S5. Generate a nano-hydrophobic layer on the surface of the board through chemical vapor deposition, and coat a UV wear-resistant coating;

[0013] S6. Perform roll pressing and curing treatment on the board to form the floor.

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

[0015] In a preferred embodiment of the present invention, the core shavings adopt a wide-narrow alternating layout, the width of the wide shavings is 8 - 12 mm, the width of the narrow shavings is 3 - 5 mm, the thickness is 0.3 - 0.5 mm, and they are arranged horizontally in an alternating structure of wide shavings - narrow shavings - wide shavings.

[0016] In a preferred embodiment of the present invention, in step S2, the plasma treatment uses a mixed gas of argon and oxygen with a volume ratio of 7:3, the radio frequency power is 30 - 50 W, and the treatment time is 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 °C, the film-forming thickness is 0.3 - 0.5 mm, and a grid structure with a pore size of 2 mm × 2 mm 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 3 -105 Ω / sq.

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

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

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

[0022] In a preferred embodiment of the present invention, in the GF / TPU buffer layer, the mass ratio of glass fiber to polyether-based TPU is 1:1.2 - 1.5 and is mixed evenly, heated to 180 - 200 °C for melting, and the film-forming thickness is 0.2 - 0.3 mm.

[0023] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0024] (1) The present invention discloses a manufacturing method of a dimensionally stable large-sized thin OSB composite floor. By incorporating nano-cellulose into the surface layer flakes and arranging them longitudinally, the core layer flakes adopt a layout of alternating wide and narrow and are arranged horizontally, and an OSB core layer is formed by hot pressing with a composite adhesive; the surface of the OSB core layer is subjected to plasma treatment and a GF / TPU interwoven layer is adhered; CNT / PE conductive films are embedded in the solid wood surface layer and the bottom layer, orthogonally stacked with the OSB core layer, a GF / TPU buffer layer is added in the middle, and a high-permeability adhesive is used for staged hot pressing to form a board; micro-arch is pre-processed at both ends of the board, and self-healing sealant microcapsules are embedded in the chamfer groove; a nano-hydrophobic layer is generated by chemical vapor deposition and a UV wear-resistant coating is coated; finally, roll pressing and curing treatment is carried out to form a floor. This method effectively solves the problems of poor dimensional stability, easy deformation, insufficient flexural rigidity, and easy failure of the adhesive layer at the joint in the prior art for OSB composite floors, significantly improves the dimensional stability, flexural performance, moisture-proof performance, anti-static performance, and joint strength of the floor, extends the service life of the floor, and is particularly suitable for large-size paving scenarios.

[0025] (2) The present invention significantly improves the activity and wettability of the surface of the OSB core layer during plasma treatment, enhancing the interfacial bonding force between the GF / TPU interwoven layer and the core layer; the GF / TPU interwoven layer disperses the hygrothermal stress through the grid structure, reducing the interlayer shear deformation. The rigidity of GF provides mechanical support, while the flexibility of TPU allows a certain degree of stress release, thus reducing the warpage degree. The combination of the two effectively inhibits the interlayer shear deformation and warpage phenomenon, and at the same time, the grid structure of the GF / TPU interwoven layer provides additional mechanical biting force, further enhancing the joint strength. Compared with the prior art, the dimensional stability and joint strength of the floor are further improved.

[0026] (3) The solid wood surface layer and bottom layer of the present invention are stacked orthogonally with the OSB core layer, offsetting the inherent anisotropic expansion of the wood and reducing the plane expansion difference of the overall board; the interposed GF / TPU buffer layer absorbs part of the stress through its flexibility, especially during the processes of thermal expansion and moisture expansion, effectively dispersing the stress and preventing warpage. 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 flexural performance of the board. Compared with the prior art, the flexural stiffness and dimensional stability of the floor are further improved.

[0027] (4) The present invention incorporates nanocellulose into the surface veneers and arranges them longitudinally to construct a three-dimensional network reinforcement structure, significantly enhancing the flexural modulus and creep resistance of the surface layer; the core veneers are arranged transversely in an alternating pattern of wide and narrow, with the wide veneers serving as the main load-bearing units to provide longitudinal flexural strength and the narrow veneers serving as flexible transition layers to fill the gaps and disperse the hygrothermal stress. The combination of the two not only enhances the strength and stability of the OSB core layer but also effectively reduces the internal stress gradient, providing a high-stability and low-expansion substrate support for the subsequent composite structure. Compared with the prior art, the dimensional stability and deformation resistance of the floor are further improved.

[0028] (5) The micro-arch design pre-processed at both ends of the board in the present invention gives the board a pre-stored deformation space, which preferentially releases the elastic strain during temperature and humidity fluctuations, reducing the peak tensile stress in the joint area; the self-healing sealant microcapsules embedded in the joint chamfer groove automatically release the polyurethane prepolymer when the joint cracks, reacting with the moisture in the environment to generate an elastomer and repair the crack. The combination of the two effectively compensates for the thermal expansion and contraction deformation during use, blocks the cumulative gradient strain, and extends the service life of the floor. Compared with the prior art, the long-term stability of the floor in large-size paving scenarios is further improved. Brief Description of the Drawings

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments described in the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings;

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

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0032] Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0033] Application overview:

[0034] There are two core defects in the existing manufacturing technology of dimensionally stable large-size thin OSB composite floors: 1. The thinning process results in a significant reduction in the thickness of the board, causing the flexural stiffness to decay cubically because the flexural stiffness is directly proportional to the cube of the thickness; when the environmental temperature and humidity fluctuate, the core layer and the surface layer generate interlayer shear stress due to the mismatch of the hygrothermal expansion coefficients of heterogeneous materials. When this stress exceeds the interfacial bonding strength, non-uniform expansion occurs, inducing asymmetric bidirectional warping; 2. In the large-size paving scenario, the inherent anisotropic hygroscopic expansion characteristics of OSB oriented flakes form a multi-dimensional stress field in the plane of the board. Minor deformations will be continuously transmitted over a long distance, resulting in the accumulation of gradient strain, and finally a tensile stress concentration is formed in the joint constraint area, leading to the brittle-ductile transition failure of the glue layer at the joint, and ultimately significant warping or joint cracking.

[0035] In view of the above problems, the present application proposes a manufacturing method for a dimensionally stable large-sized thin OSB composite floor. By constructing a composite buffer system of a GF / TPU interwoven layer, a GF / TPU buffer layer, and a GF / TPU conductive film, a dynamic balance of multi-dimensional expansion coefficients is achieved through an orthogonal stacking structure. The GF / TPU grid layer forms a three-dimensional locking interface through mechanical interlocking and melt penetration. The CNT / PE conductive film utilizes the negative expansion characteristics of carbon nanotubes to offset the swelling of wood due to moisture, and the orthogonal stacking directionality inhibits the transmission of anisotropic strain. In addition, a seam protection system with a preset micro-arch and self-healing microcapsules blocks the accumulation of gradient strain through a deformation pre-compensation and stress self-release mechanism.

[0036] Exemplary method:

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

[0038] S1. Incorporate nanocellulose into the surface flakes and arrange them longitudinally, arrange the core layer flakes in a horizontal alternating layout of wide and narrow, and hot-press the surface flakes and the core layer flakes after applying a composite adhesive to form an OSB core layer;

[0039] S2. Perform plasma treatment on the surface of the OSB core layer and attach GF / TPU interwoven layers to both sides of the OSB core layer;

[0040] S3. Embed CNT / PE conductive films in the solid wood surface layer and the bottom layer, stack them orthogonally with the OSB core layer, sandwich a GF / TPU buffer layer in the middle, bond the layers with a highly permeable adhesive, and perform hot-pressing in stages to form a board;

[0041] S4. Pre-process a micro-arch at both ends of the board and embed self-healing sealant microcapsules in the seam chamfer groove;

[0042] S5. Generate a nano-hydrophobic layer on the surface of the board through chemical vapor deposition and coat a UV wear-resistant coating;

[0043] S6. Perform roll pressing and curing treatment on the board to form a floor.

[0044] Flakes are the core raw materials for OSB manufacturing. They are cut from wood into long strip-like thin slices by a flaker and are prepared from fast-growing wood. Specifically, they include poplar and pine. The surface flakes preferably use high-quality fast-growing poplar, which has long and slender fibers and a moderate density, and can provide better longitudinal bending strength. The core layer flakes are a mixture of pine and poplar. The pine resin component can enhance the natural moisture resistance of the board, and the wood has passed through a growth period of more than 20 years to ensure the stability of the lignin and cellulose structures.

[0045] In step S1, the surface veneer shavings are 30 - 50 mm in length, 3 - 5 mm in width, and 0.3 mm in thickness; 3% - 5% nanocellulose is added to water-soluble epoxy resin with a solid content of 60% and a viscosity of 800 mPa·s; high-speed rotation mixing is carried out at a rotation speed of 2500 - 3000 rpm for 15 - 20 min to form a uniformly dispersed liquid; the diameter of the nanocellulose is 20 - 50 nm, the length is 1 - 2 μm, and the specific surface area reaches 300 m 2 / g, which can form a three-dimensional network reinforcement structure;

[0046] The surface veneer shavings are impregnated in the dispersed liquid at an impregnation pressure of 0.6 MPa for 2 - 5 min to ensure that the nanocellulose enters the pores on the surface of the surface veneer shavings and forms a continuous reinforcement phase inside the shavings; the impregnated surface veneer shavings are longitudinally arranged, and the wood fiber direction of the surface veneer shavings is consistent with the length of the board.

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

[0048] In step S1, MDI adhesive and polyvinyl alcohol PVA are compounded in a ratio of 7:3 to prepare a composite adhesive, and the sizing amount is 200 - 220 g / m 2 ;

[0049] The above-arranged surface veneer shavings and core veneer shavings are subjected to segmented hot pressing to form the OSB core layer:

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

[0051] Curing stage: The temperature is 135°C - 140°C, the pressure is 2.0 MPa, and the time is 300 - 450 seconds;

[0052] Cooling stage: A water-cooled template is used, and the cooling rate is 30°C / minute to avoid stress concentration.

[0053] In step S1, a three-dimensional network reinforcement phase is constructed in the surface veneer shavings by nanocellulose to improve the flexural modulus and creep resistance; the wide-narrow alternating core layer layout effectively disperses the wet and heat stress through the synergistic action of rigid wide sheets bearing and flexible narrow sheets absorbing energy, and cooperates with the segmented temperature-controlled hot pressing process to reduce the internal stress gradient, providing a high-stability and low-expansion substrate support for the subsequent composite structure.

[0054] In step S2, a radio frequency plasma of argon / oxygen mixed gas with a ratio of 7:3 is used, with a power of 30 - 50 W and a treatment time of 40 - 120 seconds. This increases the oxygen content on the surface of the OSB core layer, raises the content of surface active groups -OH and -COOH, reduces the wetting angle, and enhances the bonding force at the gluing interface. After plasma treatment, it is left standing for 30 minutes in an environment of 20°C and RH50% to prevent attenuation of active groups.

[0055] In step S2, preparation of the GF / TPU interwoven layer:

[0056] Select alkali-free chopped glass fibers GF with a diameter of 10 - 15 μm and a length of 3 - 5 mm, whose surface is treated with a silane coupling agent to enhance the interfacial bonding force with thermoplastic polyurethane TPU.

[0057] For thermoplastic polyurethane, select polyester-based TPU particles with a hardness of 80 - 85 Shore A.

[0058] Mix GF and TPU evenly according to a mass ratio of 1.3 - 1.7:1, heat to 180 - 200°C for melting to form a uniform GF / TPU mixed melt, extrude the GF / TPU mixed melt into a film with a thickness of 0.3 - 0.5 mm, and quickly cool and shape it through a calender roll. Among them, perform hot pressing grid forming on the formed GF / TPU interwoven layer, with a pore size of 2 mm × 2 mm, a temperature of 160 - 180°C, a pressure of 0.5 - 1.0 MPa, and a pressing time of 3 - 5 minutes; the grid depth accounts for 40 - 60% of the film thickness to enhance the interlayer mechanical interlocking ability.

[0059] Lay the GF / TPU interwoven layer flat on the surface of the OSB core layer, perform hot pressing at 160°C, with a pressure of 0.8 MPa and a duration of 8 - 10 min; at this time, TPU melts and penetrates into the pores on the OSB surface.

[0060] Step S2 significantly improves the surface activity and wettability of the OSB core layer through plasma treatment, enhances the interfacial bonding force between the GF / TPU interwoven layer and the core layer, and at the same time uses the grid structure of the GF / TPU interwoven layer to disperse the wet and thermal stresses, effectively suppressing the interlayer shear deformation and warping phenomenon. On this basis, step S3 further optimizes the electrostatic dissipation performance and overall structural stability of the board through the embedding of CNT / PE conductive film and orthogonal stacking design, providing comprehensive guarantee for the dimensional stability and functionality of the composite floor in high-end application scenarios.

[0061] In step S3, choose to use solid wood to sandwich 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 the wood is offset through orthogonal constraints, reducing the plane expansion difference of the overall board, and the flexural modulus of the solid wood is significantly higher than that of the pure OSB core layer, which can compensate for the stiffness loss of the 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 3 -10 5 Ω / sq;

[0063] The solid wood surface layer and bottom layer are microwave-dried until the moisture content ≤ 6%, then grooves are cut on their inner surfaces with a groove depth of 0.15 - 0.25 mm, a groove width of 0.3 - 0.5 mm, and a spacing of 5 - 8 mm. The CNT / PE conductive film is embedded in the grooves by rolling, with a rolling temperature of 90 - 110 °C and a pressure of 0.3 - 0.5 MPa, so that the conductive film and the wood form a mechanical interlocking structure;

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

[0065] In step S3, preparation of the GF / TPU buffer layer:

[0066] Alkali-free chopped glass fibers GF with a diameter of 10 - 15 μm and a length of 3 - 5 mm are selected, and the surface is treated with a silane coupling agent to enhance the interfacial bonding force with polyether-type TPU;

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

[0068] GF and TPU are mixed evenly at a mass ratio of 1:1.2 - 1.5. Compared with the interwoven layer, the proportion of GF is reduced to improve the flexibility of the buffer layer. It is heated to 180 - 200 °C and melted to form a uniform GF / TPU mixed melt. The GF / TPU mixed melt is extruded into a uniform and dense film with a thickness of 0.2 - 0.3 mm.

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

[0070] The high-permeability adhesive between layers is a compound of bisphenol A epoxy resin and polyurethane prepolymer at a ratio of 6:4, with a viscosity of 300 - 500 mPa·s and an application amount of 150 - 180 g / m 2 ;

[0071] The bonded wood is hot-pressed in stages:

[0072] Preheating and Penetration Stage: The temperature is 80°C - 120°C, the heating rate is 0.3°C / s, the pressure linearly increases from 0.5 MPa to 1.0 MPa, and the duration is 120 - 180 s; at this time, the adhesive starts to melt initially;

[0073] Medium Temperature and Main Pressure Stage: The temperature is 140°C - 150°C, with constant temperature control, the pressure is 2.5 - 3.0 MPa, and the duration is 300 - 400 s; at this time, the negative thermal expansion effect of the CNT / PE conductive film is triggered to offset the wood swelling strain, the adhesive starts to crosslink initially, the interfacial shear strength is enhanced, and the TPU part in the GF / TPU buffer layer melts partially and penetrates into the wood pores;

[0074] High Temperature Activation Stage: The temperature is 150°C - 165°C, the pressure is 1.5 - 2.0 MPa, and the pressure decreases at a gradient of 0.05 MPa / s based on the medium temperature and main pressure stage, and the duration is 120 - 180 s; at this time, the adhesive crosslinks for the second time, and the negative thermal expansion of the CNT / PE conductive film is strengthened;

[0075] Cooling Stage: In the first stage, the cooling rate is 5°C / min, the pressure is maintained at 1.0 MPa, and the temperature is cooled down to 100°C; in the second stage, the cooling rate is 10°C / min, the pressure is reduced to 0.5 MPa, and the temperature is cooled down to 60°C; the cooling duration is 20 - 25 min, and the thermal expansion difference between the core layer and the surface layer is released by slow cooling.

[0076] In step S3, by embedding the CNT / PE conductive film and orthogonal stacking design, the negative thermal expansion property of carbon nanotubes is used to offset the wood swelling, significantly improving the electrostatic dissipation performance and structural stability of the board. The orthogonal stacking direction effectively inhibits the anisotropic strain transfer, reducing the plane expansion difference of the overall board and compensating for the stiffness loss of the thin OSB core layer. On this basis, in step S4, by pre - processing the micro - camber and embedding the self - healing sealant micro - capsules, the gradient strain accumulation is further blocked, providing guarantee for the long - term stability of the composite floor in large - size paving scenarios.

[0077] In step S4, both ends of the board are processed into a preset micro - camber structure, the camber curvature radius R = 35 - 45 m, the camber height h = 0.15 - 0.25 mm / m, compensating for the thermal expansion and contraction deformation during use. The micro - camber design gives the board a pre - stored deformation space, preferentially releasing elastic strain during temperature and humidity fluctuations and reducing the peak tensile stress in the joint area.

[0078] V - shaped chamfer grooves are processed on the butting sides of the board, the groove depth is 1.2 - 1.8 mm, the groove opening width is 2.0 - 2.5 mm, the groove bottom fillet radius R = 0.3 - 0.5 mm, and the chamfer angle is 45 - 60°.

[0079] The shell material of the self - healing micro - capsule is urea - formaldehyde resin, and the core material is terminal isocyanate - based polyurethane prepolymer.

[0080] The polyurethane-based self-healing sealant microcapsules are embedded in the chamfer groove by spraying. The particle size of the microcapsules is 50 - 80 μm, the shell thickness is 2 - 3 μm, and the loading amount is 15 - 20 g / m 2 ; After spraying, infrared radiation curing is carried out for 30 - 60 seconds to form physical adsorption and anchoring between the microcapsules and the groove wall.

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

[0082] In step S4, by pre-processing the micro-arch and embedding the self-healing sealant microcapsules, the thermal expansion and contraction deformation during use are effectively compensated, the peak value of the tensile stress in the joint area is reduced. At the same time, using the automatic repair ability of the self-healing microcapsules when the joint cracks, the service life of the floor is extended. On this basis, in step S5, a nano-hydrophobic layer is generated by chemical vapor deposition and a UV wear-resistant coating is applied, further improving the waterproof and wear-resistant properties of the floor and ensuring its stability during long-term use.

[0083] In step S5, a fluorocarbon nano-cone array hydrophobic layer is generated on the surface of the plate by plasma-enhanced chemical vapor deposition process;

[0084] Hexamethyldisiloxane and carbon tetrafluoride are mixed at a volume ratio of 1:1.5 - 2; Deposition is carried out at a vacuum degree of 10 - 20 Pa, a radio frequency power of 100 - 150 W, a deposition temperature of 80 - 100 °C for 30 - 45 min; The thickness of the hydrophobic layer is 200 - 300 nm.

[0085] In step S5, a nano-aluminum oxide enhanced UV-cured coating is applied by roll coating process. The formula of the UV wear-resistant coating is prepared by mixing 95% acrylate UV resin, 10 - 15% nano-aluminum oxide and 2 - 3% photoinitiator; The thickness of the UV wear-resistant coating is 50 - 80 μm, the roll coating speed is 2 - 3 m / min, and it is cured by ultraviolet light irradiation, and the curing energy is 800 - 1000 mJ / cm 2 .

[0086] In step S6, roll pressing and curing are carried out by a three-roll continuous roll press;

[0087] The temperature of the preheating roll is 80 - 100 °C, and the pressure is 0.3 - 0.5 MPa, which is used to eliminate the bubbles in the coating;

[0088] The temperature of the main pressing roll is 120 - 130 °C, and the pressure is 1.2 - 1.5 MPa, which is used to promote the formation of chemical bonding between the UV coating and the hydrophobic layer;

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

[0090] Place the rolled board in a constant temperature and humidity chamber and let it stand for 48 - 72 hours to uniformly release the residual stress.

[0091] Example 1:

[0092] A manufacturing method of a dimensionally stable large - sized thin OSB composite floor, including:

[0093] Material preparation:

[0094] The surface veneer is made of high - quality fast - growing poplar wood, with slender fibers and moderate density.

[0095] The core veneer is a mixture of pine and poplar. The pine resin component enhances the natural moisture resistance of the board.

[0096] The diameter of the nanocellulose is 20 - 50 nm, the length is 1 - 2 μm, and the specific surface area is 300 m 2 / g.

[0097] The composite adhesive is compounded by MDI glue and polyvinyl alcohol (PVA) in a ratio of 7:3.

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

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

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

[0101] S1. Preparation of the OSB core layer:

[0102] The surface veneer has a length of 40 mm, a width of 4 mm, and a thickness of 0.3 mm; 4% nanocellulose is added to water - soluble epoxy resin (solid content 60%, viscosity 800 mPa·s), and it is mixed evenly by high - speed rotation (rotation speed 2800 rpm, time 18 min) to form a uniform dispersion; the surface veneer is impregnated in the dispersion, the impregnation pressure is 0.6 MPa, and the time is 3 min to ensure that the nanocellulose enters the pores of the surface veneer. The impregnated surface veneer is arranged longitudinally, and the direction of the wood fibers is consistent with the length of the board;

[0103] The width of the wide shavings is 10 mm, the width of the narrow shavings is 4 mm, and the thickness is 0.4 mm; they are arranged in an alternating structure of wide shavings - narrow shavings - wide shavings, and the direction of the wood fibers is consistent with the width of the board.

[0104] Preheating stage: The temperature rises from room temperature to 120 °C, the time is 100 seconds, and the pressure gradient is 0.5 MPa / 10 seconds.

[0105] Curing stage: The temperature is 135 °C, the pressure is 2.0 MPa, and the time is 360 seconds;

[0106] Cooling stage: Use a water-cooled template, and the cooling rate is 30 °C / minute.

[0107] S2. Lamination of the GF / TPU interwoven layer

[0108] Use a 7:3 argon / oxygen mixed gas, the radio frequency power is 40 W, and the treatment time is 80 seconds; after treatment, let it stand for 30 minutes in an environment of 20 °C and RH50%.

[0109] GF and TPU are mixed in a mass ratio of 1.5:1, heated to 190 °C and melted, extruded into a film, and hot-pressed into a grid with a thickness of 0.4 mm: the pore size is 2 mm × 2 mm, the temperature is 170 °C, the pressure is 0.8 MPa, and the pressing time is 4 minutes. The grid depth accounts for 50% of the film thickness; lay the GF / TPU interwoven layer flat on the surface of the OSB core layer, and hot-press at 160 °C, with a pressure of 0.8 MPa and a time of 9 minutes.

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

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

[0112] Preparation of the GF / TPU buffer layer: Select alkali-free chopped glass fiber GF and polyether-type TPU;

[0113] Mix GF and TPU evenly according to a mass ratio of 1:1.4. Compared with the interwoven layer, reduce the proportion of GF to improve the flexibility of the buffer layer. Heat to 180 - 200 °C and melt to 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 - 0.3 mm; lay the GF / TPU flat on one side of the CNT / PE conductive film on the solid wood surface layer and the bottom layer. The hot pressing temperature is reduced to 140 °C, the pressure is 0.6 MPa, and the time is 6 minutes; the high-permeability adhesive between layers is a compound of bisphenol A epoxy resin and polyurethane prepolymer in a ratio of 6:4, with a viscosity of 400 mPa·s and an application amount of 160 g / m2 ;

[0114] Hot pressing parameters:

[0115] Preheating and penetration stage: temperature 100°C, heating rate 0.3°C / s, pressure linearly increasing from 0.5 MPa to 1.0 MPa, time 150 s; medium temperature main pressing stage: temperature 145°C, pressure 2.8 MPa, time 360 s; high temperature activation stage: temperature 160°C, pressure 1.8 MPa, gradient pressure reduction rate 0.05 MPa / s, time 150 s; cooling stage: first stage cooling rate 5°C / min, pressure 1.0 MPa, cooling to 100°C; second stage cooling rate 10°C / min, pressure 0.5 MPa, cooling to 60°C.

[0116] S4. Micro-arch processing, arch curvature radius R = 40 m, arch height h = 0.2 mm / m; spraying polyurethane-based self-healing sealant microcapsules in the V-shaped chamfer groove, loading amount 18 g / m 2 , infrared radiation curing for 45 s.

[0117] S5. Hydrophobic layer deposition, volume ratio of hexamethyldisiloxane to carbon tetrafluoride 1:1.8; vacuum degree 15 Pa, radio frequency power 120 W, deposition temperature 90°C, time 35 min, hydrophobic layer thickness 250 nm; wear-resistant coating coating, roll coating speed 2.5 m / min, coating thickness 60 μm, curing energy 900 mJ / cm 2 .

[0118] S6. Roll pressing and curing:

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

[0120] Main pressing roller: temperature 125°C, pressure 1.3 MPa;

[0121] Sizing roller: temperature 65°C, pressure 0.9 MPa, cooling rate 15°C / min;

[0122] Place the plate after roll pressing in a constant temperature and humidity chamber (20°C, RH50%) and let it stand for 60 hours.

[0123] Example 2:

[0124] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as in Example 1 will not be elaborated, the difference between this example and Example 1 lies in;

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

[0126] Example 3:

[0127] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as those in Example 1 will not be described again. The differences between this example and Example 1 are as follows;

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

[0129] Example 4:

[0130] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as those in Example 1 will not be described again. The differences between this example and Example 1 are as follows;

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

[0132] Example 5:

[0133] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as those in Example 1 will not be described again. The differences between this example and Example 1 are as follows;

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

[0135] Example 6:

[0136] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as those in Example 1 will not be described again. The differences between this example and Example 1 are as follows;

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

[0138] Example 7:

[0139] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as those in Example 2 will not be described again. The differences between this example and Example 2 are as follows;

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

[0141] Example 8:

[0142] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as those in Example 3 will not be described again. The differences between this example and Example 3 are as follows;

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

[0144] Example 9:

[0145] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as those in Embodiment 2 will not be described again. The differences between this embodiment and Embodiment 2 are as follows;

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

[0147] Embodiment Ten:

[0148] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as those in Embodiment 3 will not be described again. The differences between this embodiment and Embodiment 3 are as follows;

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

[0150] Embodiment Eleven:

[0151] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as those in Embodiment 2 will not be described again. The differences between this embodiment and Embodiment 2 are as follows;

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

[0153] Embodiment Twelve:

[0154] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as those in Embodiment 3 will not be described again. The differences between this embodiment and Embodiment 3 are as follows;

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

[0156] Embodiment Thirteen:

[0157] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as those in Embodiment 1 will not be described again. The differences between this embodiment and Embodiment 1 are as follows;

[0158] The mass ratio of carbon nanotubes (CNT) to polyethylene (PE) in the CNT / PE conductive film is 1.5:100.

[0159] Embodiment Fourteen:

[0160] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as those in Embodiment 1 will not be described again. The differences between this embodiment and Embodiment 1 are as follows;

[0161] The mass ratio of carbon nanotubes (CNT) to polyethylene (PE) in the CNT / PE conductive film is 1.7:100.

[0162] Embodiment Fifteen:

[0163] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as in Example 1 will not be described again. The differences between this example and Example 1 are as follows;

[0164] For the CNT / PE conductive film, the carbon nanotubes (CNT) and polyethylene (PE) are in a mass ratio of 2.5:100.

[0165] Example 16:

[0166] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as in Example 1 will not be described again. The differences between this example and Example 1 are as follows;

[0167] For the CNT / PE conductive film, the carbon nanotubes (CNT) and polyethylene (PE) are in a mass ratio of 2.3:100.

[0168] Comparative Example 1:

[0169] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as in Example 1 will not be described again. The differences between this example and Example 1 are as follows;

[0170] Do not set the GF / TPU interweaving layer.

[0171] Comparative Example 2:

[0172] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as in Example 1 will not be described again. The differences between this example and Example 1 are as follows;

[0173] Do not set the GF / TPU buffer layer.

[0174] Comparative Example 3:

[0175] A manufacturing method of a dimensionally stable large-sized thin OSB composite floor, the same parts as in Example 1 will not be described again. The differences between this example and Example 1 are as follows;

[0176] Do not set the CNT / PE conductive film.

[0177] Experimental Example 1:

[0178] In this experimental example, Examples 1 to 12, and Comparative Examples 1 and 2 were selected for experiments to detect the warping degree, bending resistance performance, and joint strength performance of the floor.

[0179] The warping degree was detected according to GB / T 17657, the bending resistance performance was detected according to GB / T 17657, and the joint strength was detected according to GB / T 18103;

[0180] Warping is a key indicator to measure the dimensional stability of the floor in a hot and humid environment, and can effectively evaluate whether the floor will deform during use; bending resistance is an important indicator of the floor's bearing capacity and stiffness, and can evaluate whether the floor can withstand the expected load during use; joint strength can evaluate the strength of the glue layer at the joints of the floor in large-scale paving scenarios to prevent cracking of the joints.

[0181] Table 1 Warpage, bending resistance and joint strength test

[0182]

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

[0184] The GF / TPU interwoven layer disperses the hygrothermal stress through the grid structure and reduces the interlayer shear deformation. The rigidity of GF provides mechanical support, while the flexibility of TPU allows a certain degree of stress release, thereby reducing the warping. After GF is treated with a silane coupling agent, the interfacial bonding force with 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 the hot pressing process to form chemical bonds, further enhancing the interlayer bonding force.

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

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

[0187] In addition, the self-healing microcapsules release polyurethane prepolymers when the seams crack, reacting with moisture in the environment to form elastomers, thereby repairing the cracks and enhancing the strength of the seams. The grid structure of the interwoven layers provides additional mechanical bite force at the seams, further enhancing the strength of the seams.

[0188] Experimental Example 2:

[0189] This experimental example selects Examples 1, 13 to 16, and Comparative Example 3 to conduct experiments to detect the antistatic performance of the floor.

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

[0191] Table 2 Detection of warpage degree, bending resistance performance and antistatic performance

[0192]

[0193]

[0194] The chemical compatibility between CNT and PE determines the stability and conductivity of the conductive film. When the content of CNT is moderate, stable chemical bonding is formed between CNT and the PE matrix, and the conductivity is the best. CNT forms a conductive network in the PE matrix, and this network structure allows rapid charge conduction, thereby reducing the surface resistivity. When the content of CNT increases, the continuity of the conductive network is enhanced, and the surface resistivity is significantly reduced. The negative thermal expansion property of CNT can offset the swelling effect of wood, thereby physically reducing the warping deformation of the floor.

[0195] Based on the inspiration of the ideal embodiments of the present invention, through the above description, relevant personnel can completely make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope 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: Includes steps: S1. Add nanocellulose to the surface flakes and arrange them longitudinally, arrange the core flakes horizontally in a wide and narrow alternating layout, apply composite adhesive to the surface flakes and the core flakes and then hot press them to form an OSB core layer; S2, plasma treatment is performed on the surface of the OSB core layer, and GF / TPU interlaced layers are laminated on both sides of the OSB core layer; S3. CNT / PE conductive film is embedded in the surface and bottom layers of solid wood, and stacked with the OSB core layer in an orthogonal direction, with a GF / TPU buffer layer sandwiched in the middle, and the layers are bonded with a high-permeability adhesive, and hot-pressed in stages to form a board; S4. Pre-process the micro-arch at both ends of the plate and embed self-repairing sealant microcapsules in the chamfered groove of the joint; S5, generating a nano hydrophobic layer on the surface of the plate by chemical vapor deposition, and coating it with a UV wear-resistant coating; S6. Roll-pressing and curing the board to form a floor.

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 flakes are 30-50 mm long, 3-5 mm wide and 0.3 mm thick; the amount of nanocellulose added is 3%-5% of the mass of the surface flakes, and the diameter of the nanocellulose is 20-50 nm and the length is 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 flakes are arranged in an alternating wide and narrow layout, with the wide flakes being 8-12mm wide, the narrow flakes being 3-5mm wide, and the thickness being 0.3-0.5mm. They are arranged horizontally in an alternating structure of wide flakes-narrow flakes-wide flakes.

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 mixed gas of argon and oxygen with a volume ratio of 7:3, a radio frequency power of 30-50 W, 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 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° C., the film thickness is 0.3-0.5 mm, and a grid structure with a pore size of 2 mm×2 mm is formed by 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 thickness of the conductive film is 0.1-0.2 mm, and the surface resistivity is 10 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: The micro-arch curvature radius of the pre-processed micro-arch in step S4 is 35-45 mm, the arch height is 0.15-0.25 mm / m, the groove depth of the joint chamfer groove is 1.2-1.8 mm, and the groove width is 2.0-2.5 mm.

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 formed by a plasma enhanced chemical vapor deposition process, the volume ratio of hexamethyldisiloxane to carbon tetrafluoride is 1:1.5-2, the deposition temperature is 80-100° C., and the thickness of the hydrophobic layer is 200-300 nm.

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

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

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