Waterproof breathable bamboo board and preparation method thereof

Abstract

The invention relates to a waterproof breathable bamboo board and a preparation method thereof.The preparation method of the waterproof breathable bamboo board comprises the following steps that (1) bamboo flakes obtained after raw bamboo processing and bamboo fine materials are glued, and nano calcium carbonate is added into the bamboo fine materials before gluing; then the glued bamboo flakes and the bamboo fine materials are laid in a layered and oriented mode according to the structure of the fine material layer, the bamboo flake layer and the fine material layer, and a plate blank is obtained; and (2) the plate blank obtained in the step (1) is subjected to hot press molding, and the waterproof and breathable bamboo plate with the internal pore diameter being 1-10 microns and the design density being larger than 600 kg / m < 3 > is obtained. The waterproof breathable bamboo board can meet the functional requirements of water resistance, breathability and high hydrophobicity and drainage at the same time, and the production efficiency is remarkably improved on the premise that the cost is not increased.

Description

Technical Field

[0001] The present invention relates to the technical field of building boards, and in particular to a waterproof and breathable bamboo board and a preparation method thereof. Background Art

[0002] Modern bamboo-wood structures are widely used in residential and public buildings due to their environmental friendliness, aesthetics, and ease of construction. As a key component of timber-framed buildings, the structure and performance of timber walls play a decisive role in the durability of the building.

[0003] Currently, conventional wooden structure walls adopt a structural form that combines a waterproof breathable membrane with a structural covering panel. For example, CN215829700U discloses a prefabricated lightweight wooden structure wall, including a wall body and a lateral connection device. The wall body includes a fireproof gypsum board, a wooden frame, thermal insulation cotton, a covering panel, a waterproof breathable membrane, a water-resistant strip, and an exterior decorative panel. The wooden frame is filled with thermal insulation cotton, the fireproof gypsum board is fixed to the inside of the wooden frame, the covering panel is fixed to the outside of the wooden frame, the waterproof breathable membrane is fixed to the outside of the covering panel, and the water-resistant strip is fixed to the outside of the waterproof breathable membrane. The waterproof breathable membrane can block the intrusion of external liquid water while allowing water vapor to diffuse, preventing the components from rotting and moldy, thereby ensuring the durability of the wooden structure; the covering panel mainly provides the wall with lateral force resistance, improving the overall strength and stability of the wall.

[0004] However, this construction has certain drawbacks in practical application. From a construction perspective, the waterproof and breathable membrane and cladding panels must be installed separately, a complex process requiring high precision installation and increasing construction costs. Furthermore, the membrane and cladding panels have different expansion coefficients, which can lead to separation and delamination over long periods of use. This degrades the waterproof and breathable properties, ultimately causing the wall's waterproofing to fail, severely impacting the service life and safety of wooden structures. Furthermore, some materials used in traditional construction consume high energy during production and transportation, and the membranes are often non-degradable, polluting the environment upon disposal.

[0005] CN112575890A discloses a breathable and waterproof solid bamboo fiberboard, comprising a base, a wall above the base, a sealing opening in the wall, a swing-open door device in front of the sealing opening, the swing-open door device comprising a first sealing plate and a second sealing plate. The wall is a spliced ​​structure, the wall includes a shock-absorbing layer surrounded by stoppers, a waterproof layer on the outer side of the shock-absorbing layer, and an anti-scratch layer on the outer side of the waterproof layer. This invention achieves controllable breathability through the swing-open door device and waterproofing through the waterproof layer, but the board structure is relatively complex, which has certain limitations in large-scale building board applications.

[0006] Therefore, it is necessary to develop a new type of structural panel with waterproof and breathable properties for wooden structure walls, in order to replace the conventional waterproof and breathable membrane and covering panel structure through innovative materials and processes, and provide new ideas for the development of wooden structure buildings. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a waterproof and breathable bamboo board and a preparation method thereof, which can simultaneously meet the functional requirements of waterproofing, breathability and high hydrophobicity and drainage, and increase production efficiency without increasing costs.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing a waterproof and breathable bamboo board, the method comprising the following steps:

[0010] (1) Bamboo shavings and bamboo fines obtained after processing raw bamboo are glued separately, and nano calcium carbonate is added to the bamboo fines before gluing; then the glued bamboo shavings and bamboo fines are layered and oriented according to the structure of fine material layer, bamboo shaving layer and fine material layer to obtain a slab;

[0011] (2) The slab obtained in step (1) is hot-pressed to obtain a slab with an internal pore diameter of 1-10 μm and a design density of >600 kg / m 3 Waterproof and breathable bamboo panels.

[0012] Based on the fact that liquid water typically exists as droplets due to surface tension, with a minimum droplet diameter of approximately 20 μm and a water vapor molecule diameter of 0.0004 μm, the preparation method provided by the present invention controls the internal pore diameter of the board to between 1 and 10 μm, effectively preventing liquid water penetration while ensuring the smooth passage of vaporous water. The waterproof and breathable bamboo board utilizes a bamboo shaving layer as the strength material, providing both in-plane and out-of-plane strength. The fine material layer serves as a waterproof and breathable layer. The inherent microporous structure of the bamboo fine material, combined with the controlled pore diameter within the board, achieves the board's waterproof and breathable properties. Furthermore, the nano-calcium carbonate with its irregular three-dimensional microporous structure within the bamboo fine material helps improve the passage efficiency of vaporous water molecules.

[0013] The internal pore diameter of the waterproof and breathable bamboo board is 1-10 μm, for example, 1 μm, 3 μm, 5 μm, 8 μm or 10 μm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0014] The design density of the waterproof and breathable bamboo board is greater than 600kg / m 3 , for example, it can be 650kg / m 3 , 700kg / m3 , 750kg / m 3 , 800kg / m 3 or 850kg / m 3 , but not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0015] Preferably, the processing in step (1) includes the steps of sawing the raw bamboo, removing green and yellow parts, slicing the bamboo tube, drying and screening.

[0016] Preferably, the moisture content of the bamboo shavings in step (1) is 8-12%, for example, 8%, 9%, 10%, 11% or 12%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] Preferably, the bamboo shavings in step (1) have a thickness of 0.7-0.9 mm, a width of 10-30 mm, and a length of 115-125 mm.

[0018] The thickness of the bamboo shavings in step (1) is 0.7-0.9 mm, for example, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm or 0.9 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0019] The width of the bamboo shavings in step (1) is 10-30 mm, for example, 10 mm, 15 mm, 20 mm, 25 mm or 30 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] The length of the bamboo shavings in step (1) is 115-125 mm, for example, 115 mm, 118 mm, 120 mm, 122 mm or 125 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] Preferably, the bamboo fine material in step (1) includes at least one of bamboo sawdust, bamboo powder or bamboo fiber.

[0022] Preferably, the mass of the nano-calcium carbonate in step (1) is 5-10wt% of the mass of the bamboo fine material, for example, it can be 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0023] Preferably, the gluing of the bamboo shavings in step (1) is carried out by atomizing and spraying glue.

[0024] Preferably, the adhesive used for gluing the bamboo shavings in step (1) includes phenolic resin adhesive and / or pMDI adhesive.

[0025] Preferably, the amount of glue applied to the bamboo shavings in step (1) is 7-9wt%, for example, 7wt%, 7.5wt%, 8wt%, 8.5wt% or 9wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] Preferably, the gluing of the bamboo fine material in step (1) is carried out by rolling glue mixing.

[0027] Preferably, the adhesive used for gluing the bamboo fine material in step (1) comprises powdered polyurethane adhesive.

[0028] The present invention adopts a powdered polyurethane adhesive combined with a subsequent hot pressing process to achieve point gluing of each bamboo fine material, thereby preventing the adhesive layer from affecting the gas passage efficiency; the polyurethane adhesive will form an elastic adhesive layer after hot pressing, and during the process of nailing the nail connector, its flexible adhesive layer can completely wrap the nail rod, thereby ensuring that the waterproof and breathable performance of the board is not affected by the nail hole.

[0029] Preferably, the glue application amount of the bamboo fine material in step (1) is 9-11wt%, for example, it can be 9wt%, 9.5wt%, 10wt%, 10.5wt% or 11wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] Preferably, based on the total mass fraction being 100%, the mass fraction of the fine material layer in step (1) is 20-40%, the mass fraction of the bamboo shavings layer is 20-60%, and the mass fraction of the fine material layer is 20-40%.

[0031] The mass proportion of the fine material layer is 20-40%, for example, it can be 20%, 25%, 30%, 35% or 40%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] The mass proportion of the bamboo shavings layer is 20-60%, for example, it can be 20%, 30%, 40%, 50% or 60%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] The mass proportion of the fine material layer is 20-40%, for example, it can be 20%, 25%, 30%, 35% or 40%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the bamboo shavings layer includes a longitudinal bamboo shavings layer, a transverse bamboo shavings layer and a longitudinal bamboo shavings layer which are stacked and laid in sequence.

[0035] Preferably, the orientation rate of the layered directional paving in step (1) is ≥85%, and the paving angle is ≤15°.

[0036] The orientation rate of the layered directional paving in step (1) is ≥85%, for example, it can be 85%, 86%, 88%, 90% or 92%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0037] The paving angle of the layered directional paving in step (1) is ≤15°, for example, it can be 15°, 12°, 10°, 8° or 6°, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0038] Preferably, the pressure of the hot pressing molding in step (2) is ≥4 MPa, for example, it can be 4 MPa, 5 MPa, 6 MPa, 7 MPa or 8 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the hot pressing molding in step (2) is carried out using a large-format hot press machine of 8 feet × 64 feet.

[0040] The waterproof and breathable bamboo board provided by the present invention is processed by using a large-format hot press to perform a hot pressing and forming operation in one step, thereby achieving high processing efficiency.

[0041] Preferably, the surface of the steel plate used for hot pressing in step (2) has concave and convex points, and the density of the concave and convex points is greater than 10 / cm 2 , for example, it can be 11 / cm 2 , 12 pieces / cm 2 , 13 pieces / cm 2 , 14 pieces / cm 2 or 15 pieces / cm 2 , but not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0042] The steel plate of the hot press used for hot pressing in the present invention has dense concave and convex points, which makes the surface of the formed plate hydrophobic and enhances the drainage performance of the plate. When liquid water contacts the surface of the plate, it can flow away quickly by gravity, reducing the residence time of liquid water on the surface of the plate and the risk of penetration.

[0043] Preferably, the hot pressing temperature of the hot pressing molding in step (2) is 180-200° C., and the hot pressing time is 60-75 s / mm.

[0044] The hot pressing temperature of the hot pressing molding in step (2) is 180-200°C, for example, it can be 180°C, 185°C, 190°C, 195°C or 200°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0045] The hot pressing time of the hot pressing molding in step (2) is 60-75s / mm, for example, it can be 60s / mm, 62s / mm, 65s / mm, 70s / mm or 75s / mm, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0046] Preferably, the design thickness of the waterproof and breathable bamboo board in step (2) is 17-19 mm, for example, it can be 17 mm, 17.5 mm, 18 mm, 18.5 mm or 19 mm, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0047] In a second aspect, the present invention provides a waterproof and breathable bamboo board, which is prepared by the preparation method of the waterproof and breathable bamboo board described in the first aspect.

[0048] The waterproof and breathable bamboo board provided by the present invention has the functions of waterproofing, breathability and high hydrophobicity while ensuring excellent mechanical properties, and can be applied to wooden structure walls of residential or public buildings.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The preparation method of the waterproof and breathable bamboo board provided by the present invention controls the internal pore diameter of the board to be between 1-10 μm by adjusting the ratio of bamboo fines to bamboo shavings, controlling the moisture content of bamboo shavings, hot pressing forming pressure and board density. This pore diameter range allows gaseous water molecules to pass through smoothly, meeting the breathability requirements, and at the same time can effectively block the penetration of liquid water based on the surface tension principle, thereby achieving a good waterproof and breathable effect.

[0051] (2) The present invention adds nano-calcium carbonate with irregular three-dimensional structure to the bamboo fine material, which ensures the three-dimensional microporous structure of the fine material layer. At the same time, the special gluing method and hot pressing process realize the point gluing between the fine materials. The combination of the two helps to improve the passing efficiency of gaseous water molecules in the board.

[0052] (3) The present invention uses a steel plate with concave and convex points on the surface for hot pressing. The pressed plate surface has hydrophobic properties, which not only significantly enhances the drainage capacity of the plate, avoids the accumulation and penetration of liquid water on the surface of the plate, but also improves the aesthetics and cleaning convenience of the plate; in addition, the waterproof and breathable bamboo plate processing uses a large-format hot press to perform a hot pressing operation in one time, which has high processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a schematic structural diagram of a slab provided in Example 1 of the present invention;

[0054] Figure 2 Schematic diagram of the surface hydrophobic structure of the waterproof and breathable bamboo board provided in Example 1 of the present invention.

[0055] Among them: 1, fine material layer; 2, longitudinal bamboo shavings layer; 3, transverse bamboo shavings layer. DETAILED DESCRIPTION

[0056] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0057] Example 1

[0058] This embodiment provides a waterproof and breathable bamboo board with a design thickness of 18 mm and a design density of 850 kg / m 3 The preparation method of the waterproof and breathable bamboo board comprises the following steps:

[0059] (1) The raw bamboo is sequentially sawed, de-greened, de-yellowed, sliced, dried, and sieved to obtain bamboo shavings and bamboo fines with a moisture content of 10%, a thickness of 0.8 mm, a width of 20 mm, and a length of 120 mm; the bamboo fines include bamboo sawdust and bamboo powder.

[0060] The bamboo shavings were glued by atomizing and spraying pMDI adhesive, with a glue application amount of 8wt%. The bamboo fines and nano-calcium carbonate were glued by rolling and mixing powdered polyurethane adhesive, with a glue application amount of 10wt%. The mass of the nano-calcium carbonate was 8wt% of the mass of the bamboo fines.

[0061] Then the glued bamboo shavings and bamboo fine materials are layered and oriented according to the structure of fine material layer 1, bamboo shavings layer and fine material layer 1. Taking the total mass fraction as 100%, the mass proportion of the fine material layer is 30%, the mass proportion of the bamboo shavings layer is 40%, and the mass proportion of the fine material layer is 30%; wherein, the bamboo shavings layer includes a longitudinal bamboo shavings layer 2, a transverse bamboo shavings layer 3 and a longitudinal bamboo shavings layer 2 stacked and paved in sequence; the orientation rate of the layered directional paving is 85%, the paving angle is 15°, and a slab is obtained. The structural schematic diagram is shown as follows Figure 1 shown.

[0062] (2) The slab obtained in step (1) is hot-pressed, and the surface of the steel plate used for hot-pressing has concave and convex points, and the density of the concave and convex points is 15 / cm 2 The hot pressing pressure is 6MPa, the hot pressing temperature is 200℃, and the hot pressing time is 60s / mm. The waterproof and breathable bamboo board with an internal pore diameter of 1-10μm is obtained. The schematic diagram of the surface hydrophobic structure of the waterproof and breathable bamboo board is as shown in FIG. Figure 2As shown in the figure, it can be seen that the concave-convex structure on the surface of the waterproof and breathable bamboo board makes it hydrophobic, thereby enhancing the drainage performance.

[0063] Example 2

[0064] This embodiment provides a waterproof and breathable bamboo board with a design thickness of 18 mm and a design density of 750 kg / m 3 The preparation method of the waterproof and breathable bamboo board comprises the following steps:

[0065] (1) The raw bamboo is sequentially sawed, de-greened, de-yellowed, sliced ​​into bamboo tubes, dried, and sieved to obtain bamboo shavings and bamboo fines with a moisture content of 8%, a thickness of 0.7 mm, a width of 10 mm, and a length of 115 mm; the bamboo fines include bamboo sawdust and bamboo fiber.

[0066] The bamboo shavings were glued by atomizing and spraying pMDI adhesive, with a glue application amount of 7wt%. The bamboo fines and nano-calcium carbonate were glued by rolling and mixing powdered polyurethane adhesive, with a glue application amount of 9wt%. The mass of the nano-calcium carbonate was 5wt% of the mass of the bamboo fines.

[0067] Then, the glued bamboo shavings and bamboo fine materials are layered and oriented according to the structure of fine material layer 1, bamboo shaving layer and fine material layer 1. With the total mass fraction being 100%, the mass proportion of the fine material layer is 20%, the mass proportion of the bamboo shaving layer is 60%, and the mass proportion of the fine material layer is 20%; wherein the bamboo shaving layer includes a longitudinal bamboo shaving layer 2, a transverse bamboo shaving layer 3 and a longitudinal bamboo shaving layer 2 stacked and paved in sequence; the orientation rate of the layered oriented paving is 85%, and the paving angle is 15°, thereby obtaining a slab;

[0068] (2) The slab obtained in step (1) is hot-pressed, and the surface of the steel plate used for hot-pressing has concave and convex points, and the density of the concave and convex points is 12 / cm 2 The hot pressing pressure is 5 MPa, the hot pressing temperature is 190°C, and the hot pressing time is 70 s / mm, and a waterproof and breathable bamboo board with an internal pore diameter of 1-10 μm is obtained.

[0069] Example 3

[0070] This embodiment provides a waterproof and breathable bamboo board with a design thickness of 18 mm and a design density of 650 kg / m 3 The preparation method of the waterproof and breathable bamboo board comprises the following steps:

[0071] (1) The raw bamboo is sawed, de-greened, de-yellowed, sliced, dried, and sieved in sequence to obtain bamboo shavings and bamboo fines with a moisture content of 12%, a thickness of 0.9 mm, a width of 30 mm, and a length of 125 mm; the bamboo fines include bamboo powder and bamboo fiber.

[0072] Phenolic resin adhesive was applied to bamboo shavings by atomizing spraying, with an application amount of 9wt%. Powdered polyurethane adhesive was applied to bamboo fines and nano-calcium carbonate by rolling mixing, with an application amount of 11wt%. The mass of the nano-calcium carbonate was 10wt% of the mass of the bamboo fines.

[0073] Then, the glued bamboo shavings and bamboo fine materials are layered and oriented according to the structure of fine material layer 1, bamboo shaving layer and fine material layer 1. With the total mass fraction being 100%, the mass proportion of the fine material layer is 40%, the mass proportion of the bamboo shaving layer is 20%, and the mass proportion of the fine material layer is 40%; wherein, the bamboo shaving layer includes a longitudinal bamboo shaving layer 2, a transverse bamboo shaving layer 3 and a longitudinal bamboo shaving layer 2 stacked and paved in sequence; the orientation rate of the layered oriented paving is 85%, and the paving angle is 15°, thereby obtaining a slab;

[0074] (2) The slab obtained in step (1) is hot-pressed, and the surface of the steel plate used for hot-pressing has concave and convex points, and the density of the concave and convex points is 11 / cm 2 The hot pressing pressure is 4 MPa, the hot pressing temperature is 180°C, and the hot pressing time is 75 s / mm, and a waterproof and breathable bamboo board with an internal pore diameter of 1-10 μm is obtained.

[0075] Example 4

[0076] This embodiment provides a waterproof and breathable bamboo board. The difference from embodiment 1 is that in step (1), there is no step of removing the green and yellow parts of the original bamboo. The rest is the same as embodiment 1.

[0077] Comparative Example 1

[0078] This comparative example provides a waterproof and breathable bamboo board. The difference from Example 1 is that the design density of the waterproof and breathable bamboo board is adjusted to 400 kg / m 3 , the rest are the same as in Example 1.

[0079] Comparative Example 2

[0080] This comparative example provides a waterproof and breathable bamboo board, which differs from Example 1 in that nano-calcium carbonate is not added in the sizing of the bamboo fine material in step (1), and the rest is the same as Example 1.

[0081] The waterproof and breathable bamboo boards provided in Examples 1-4 and Comparative Examples 1 and 2 were tested for density using the "Test Methods for Physical and Chemical Properties of Artificial Boards and Finished Artificial Boards" (GB / T 17657-2022), for mechanical properties using the "Test Methods for Physical and Chemical Properties of Artificial Boards and Finished Artificial Boards" (GB / T 17657-2022), and for water vapor transmission rate using the "Test Method for Water Vapor Permeability of Building Materials and Their Products" (GB / T 17146-2015). The results are shown in Table 1.

[0082] Table 1

[0083]

[0084] It can be seen from Table 1 that the waterproof and breathable bamboo board provided by the present invention has excellent waterproof and breathable properties and mechanical properties, and can meet the requirements for use as a wood structure wall board.

[0085] A comparison of Example 1 and Example 4 shows that without removing the green and yellowing of the raw bamboo, the gluing and mechanical properties of the waterproof and breathable bamboo board are reduced. A comparison of Example 1 and Comparative Example 1 shows that too low a design density reduces the static bending strength and elastic modulus along the grain of the waterproof and breathable bamboo board, and does not significantly improve the water vapor transmission rate of the board. A comparison of Example 1 and Comparative Example 2 shows that without adding nano-calcium carbonate during the sizing process of the bamboo fines, the water vapor transmission rate is significantly reduced.

[0086] In summary, the preparation method of the waterproof and breathable bamboo board provided by the present invention controls the internal pore diameter of the board to between 1-10 μm by adjusting the ratio of bamboo fine material to bamboo shavings, controlling the moisture content of bamboo shavings, hot pressing molding pressure and board density. This pore diameter range allows gaseous water molecules to pass through smoothly, meeting the breathability requirements, and at the same time can effectively block the penetration of liquid water based on the principle of surface tension, thereby achieving good waterproof and breathable effects.

[0087] The present invention adds nano calcium carbonate with irregular three-dimensional structure to the bamboo fine material, ensuring the three-dimensional microporous structure of the fine material layer. At the same time, the special gluing method and hot pressing process realize the point gluing between the fine materials. The combination of the two helps to improve the passing efficiency of gaseous water molecules in the board.

[0088] The present invention uses a steel plate with concave and convex points on the surface for hot pressing. The pressed plate surface has hydrophobic properties, which not only significantly enhances the drainage capacity of the plate, avoids the accumulation and penetration of liquid water on the surface of the plate, but also improves the aesthetics and cleaning convenience of the plate; in addition, the waterproof and breathable bamboo plate processing uses a large-format hot press to perform a one-time hot pressing operation, which has high processing efficiency.

[0089] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a waterproof and breathable bamboo board, characterized in that: The preparation method comprises the following steps: (1) Bamboo shavings and bamboo fines obtained after processing raw bamboo are glued separately, and nano calcium carbonate is added to the bamboo fines before gluing; then the glued bamboo shavings and bamboo fines are layered and oriented according to the structure of fine material layer, bamboo shaving layer and fine material layer to obtain a slab; (2) The slab obtained in step (1) is hot-pressed to obtain a slab with an internal pore diameter of 1-10 μm and a design density of >600 kg / m 3 Waterproof and breathable bamboo panels.

2. The preparation method according to claim 1, characterized in that The processing in step (1) includes the steps of sawing the original bamboo, removing the green and yellow parts, slicing the bamboo tube, drying and screening.

3. The preparation method according to claim 1 or 2, characterized in that The moisture content of the bamboo shavings in step (1) is 8-12%; Preferably, the bamboo shavings in step (1) have a thickness of 0.7-0.9 mm, a width of 10-30 mm, and a length of 115-125 mm.

4. The preparation method according to any one of claims 1 to 3, characterized in that The bamboo fine material in step (1) comprises at least one of bamboo sawdust, bamboo powder or bamboo fiber; Preferably, the mass of the nano-calcium carbonate in step (1) is 5-10 wt% of the mass of the bamboo fine material.

5. The preparation method according to any one of claims 1 to 4, characterized in that The bamboo shavings in step (1) are glued by spraying with atomized glue; Preferably, the adhesive used for sizing the bamboo shavings in step (1) includes phenolic resin adhesive and / or pMDI adhesive; Preferably, the amount of glue applied to the bamboo shavings in step (1) is 7-9 wt%.

6. The preparation method according to any one of claims 1 to 5, characterized in that The gluing of the bamboo fine material in step (1) is carried out by rolling glue mixing; Preferably, the adhesive used for gluing the bamboo fine material in step (1) comprises powdered polyurethane adhesive; Preferably, the amount of glue applied to the bamboo fine material in step (1) is 9-11 wt%.

7. The preparation method according to any one of claims 1 to 6, characterized in that Taking the total mass fraction as 100%, the mass fraction of the fine material layer in step (1) is 20-40%, the mass fraction of the bamboo shavings layer is 20-60%, and the mass fraction of the fine material layer is 20-40%; Preferably, the bamboo shavings layer comprises a longitudinal bamboo shavings layer, a transverse bamboo shavings layer and a longitudinal bamboo shavings layer stacked and laid in sequence; Preferably, the orientation rate of the layered directional paving in step (1) is ≥85%, and the paving angle is ≤15°.

8. The preparation method according to any one of claims 1 to 7, characterized in that The pressure of the hot pressing molding in step (2) is ≥4 MPa; Preferably, the surface of the steel plate used for hot pressing in step (2) has concave and convex points, and the density of the concave and convex points is greater than 10 / cm 2 ; Preferably, the hot pressing temperature of the hot pressing molding in step (2) is 180-200° C., and the hot pressing time is 60-75 s / mm.

9. The preparation method according to any one of claims 1 to 8, characterized in that The designed thickness of the waterproof and breathable bamboo board in step (2) is 17-19 mm.

10. A waterproof and breathable bamboo board, characterized in that: The waterproof and breathable bamboo board is prepared by the preparation method of the waterproof and breathable bamboo board according to any one of claims 1 to 9.

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