Bamboo anti-cracking plywood and preparation method thereof

Abstract

The invention relates to the technical field of bamboo plywood, and discloses a bamboo anti-cracking plywood and a preparation method thereof.The bamboo anti-cracking plywood comprises multiple layers of plywood bodies, each layer of plywood body is composed of bamboo chips through a first adhesive, and the first adhesive comprises 20-40% by mass of cellosilk; the adjacent plate bodies are connected through a second adhesive, and screen cloth is arranged between the adjacent plate bodies. The anti-cracking performance of the bamboo plywood can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of bamboo plywood, and in particular to a bamboo anti-cracking plywood and a preparation method thereof. Background Art

[0002] At present, the common decorative panels on the market mainly include solid wood boards, fiberboards, plywood and other types. These panels are widely used in interior decoration, furniture manufacturing and other industries due to their low cost and stable performance. However, most traditional wood panels rely on forest resources, which not only consumes a lot of natural resources, but also may lead to the depletion of forest resources. In recent years, with the improvement of environmental awareness and technological progress, the research and development of using sustainable renewable materials as substrates has gradually received attention. Among them, bamboo, as a natural resource with fast growth and short maturity period, has become one of the ideal choices to replace traditional wood materials.

[0003] Bamboo plywood is a board made of bamboo as the main raw material, through a series of processes such as bamboo lamination technology. The advantage of bamboo plywood is that it maintains the natural texture of bamboo while having good physical and mechanical properties. It has a wide range of applications in home decoration and other fields.

[0004] In bamboo plywood, adhesive is applied to the surface of bamboo sheets and then formed and cured by hot pressing. However, due to the wide application of bamboo plywood, bamboo plywood will still crack in some environments with large temperature differences, which limits the application of bamboo plywood. Summary of the invention

[0005] In a first aspect, the present application provides a bamboo anti-cracking plywood, which improves the anti-cracking ability of the bamboo plywood by mixing fiber filaments into the adhesive to improve the connection force between bamboo pieces.

[0006] The present application provides a bamboo anti-cracking plywood, which adopts the following technical solution: A bamboo anti-cracking plywood comprises a multi-layer board body, each layer of the board body is formed by bamboo slices by using a first adhesive, wherein the first adhesive comprises fiber filaments with a mass fraction of 20-40%; adjacent board bodies are connected by a second adhesive, and mesh cloth is arranged between adjacent board bodies.

[0007] By adopting the above technical solution, by cooperating with the first adhesive and the fiber filaments, the fiber filaments can form stress points in the plywood system, thereby greatly improving the force between the bamboo pieces, thereby reducing cracking caused by changes in temperature and humidity; and the structure between the layers is connected together by the mesh and the second adhesive, thereby also stably connecting the bamboo sheet layer structure between the layers, further improving the anti-cracking performance of the bamboo plywood.

[0008] Optionally, the average length of the fiber filaments is 1.5-3 cm.

[0009] By adopting the above technical solution, the length of the fiber filaments is within this range, which can better form force points between the bamboo pieces, thereby achieving the effect of improving the connection force between the bamboo pieces.

[0010] Optionally, the first adhesive and the second adhesive are independently selected from one or more of urea-formaldehyde resin, phenol-formaldehyde resin, and melamine-formaldehyde resin.

[0011] Optionally, before use, the bamboo slices are roughened using a roughening device.

[0012] By adopting the above technical solution, the surface of the bamboo piece is roughened by using a roughening device, so that the surface of the bamboo piece has grains, thereby reducing the smoothness of the surface of the bamboo piece, which is conducive to the formation of stress points of fiber filaments and adhesives in the grains, thereby better improving the anti-cracking performance of the plywood. The roughening device is usually a rotating drum, and the outer surface of the drum is evenly provided with a wire-like structure. When the bamboo piece passes under the drum, the drum can form grains on the surface of the bamboo piece.

[0013] Optionally, the area ratio of the roughened surface of the bamboo piece is 30-45%.

[0014] By adopting the above technical solution, the mechanical properties and anti-cracking performance of the plywood can be combined.

[0015] Optionally, the bamboo pieces have an outer skin layer and an inner layer. When a plurality of the bamboo pieces are connected together, the outer skin layers abut against each other, and the inner layers abut against each other.

[0016] By adopting the above technical solution, due to its characteristics, the bamboo pieces are prone to bend towards the inner layer over time. The plywood can greatly reduce the reduction in mechanical properties caused by the bending characteristics of the bamboo pieces through this alternating staggered manner.

[0017] Optionally, the fiber filament is selected from one of natural palm fiber and artificial fiber.

[0018] In a second aspect, the present application provides a method for preparing the anti-cracking plywood in the above-mentioned solution.

[0019] A method for preparing a bamboo anti-cracking plywood comprises the following steps: S1. Cutting: Select bamboo and process it into strips; S2, sequentially performing rough milling, steaming, drying, carbonizing, drying, and fine milling to obtain bamboo chips of length, width, and thickness; S3, roughening the surface of the bamboo pieces using a roughening device, and then bonding the bamboo pieces together using a first adhesive; bonding the upper and lower plates together using a second adhesive and a mesh cloth; S4, loading into a hot press machine for hot pressing and then cutting.

[0020] In summary, the present application includes at least one of the following beneficial effects: 1. In the solution of the present application, by introducing fiber filaments into the adhesive, a large number of force points can be formed at the bonding interface, thereby increasing the force between the bamboo pieces, so that the obtained bamboo plywood has good anti-cracking performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of plywood; Figure 2 It is a schematic diagram of the distribution of bamboo pieces in this application. DETAILED DESCRIPTION

[0022] Example 1 A method for preparing a bamboo anti-cracking plywood comprises the following steps: S1. Slice: Select 5-year-old bamboos that are free of insects and straight in shape, and process them into strips; S2, using a rough milling machine to remove the green and yellow of the bamboo slices; then steaming the roughly milled bamboo strips; drying the steamed bamboo slices at 35°C and keeping ventilation to a moisture content of 8-12%; using a carbonization furnace, pressurizing saturated steam to 2 atmospheric pressures, temperature conditions: 140°C, for carbonization; then drying the carbonized bamboo slices again; and then fine milling the length, width and thickness to obtain the bamboo slices of the present application; S3, using a roughening device to roughen the surface of the bamboo pieces, the roughened area accounts for about 45% of the surface area of ​​the bamboo pieces; then using the first adhesive to bond the bamboo pieces together to form a board; refer to Figure 1 and Figure 2In this embodiment, the plywood is composed of three layers of boards, the thickness of the bamboo slices in the middle layer is greater than the thickness of the bamboo slices on the upper and lower sides, and the length directions of the bamboo slices in adjacent boards are perpendicular, and when the bamboo slices are connected together, the surface layer and the adjacent inner layer are in contact with each other, and the inner layer and the adjacent surface layer are in contact with each other; one side of the bamboo slices on the surface of the board is also roughened by a roughening device; the adjacent boards are connected together by a second adhesive, and a mesh is laid on the connection interface, and the mesh can be selected from a glass fiber mesh; The first adhesive is selected from phenolic resin, and the first adhesive is mixed with 20wt% of brown fiber, and the average length of the brown fiber is 2.5-3cm; the second adhesive is selected from phenolic resin; S4. The assembled board blanks are placed into a hot press for forming and hot pressing. The hot pressing pressure is 2.5 MPa, the hot pressing temperature is 140° C., and the hot pressing time is 4 min. Finally, the board blanks are cut to obtain the plywood of the present application.

[0023] Example 2 A method for preparing a bamboo anti-cracking plywood comprises the following steps: S1. Slice: Select 5-year-old bamboos that are free of insects and straight in shape, and process them into strips; S2, using a rough milling machine to remove the green and yellow of the bamboo slices; then steaming the roughly milled bamboo strips; drying the steamed bamboo slices at 35°C and keeping ventilation to a moisture content of 8-12%; using a carbonization furnace, pressurizing saturated steam to 2 atmospheric pressures, temperature conditions: 140°C, for carbonization; then drying the carbonized bamboo slices again; and then fine milling the length, width and thickness to obtain the bamboo slices of the present application; S3, using a roughening device to roughen the surface of the bamboo pieces, the roughened area accounts for about 40% of the surface area of ​​the bamboo pieces; then using the first adhesive to bond the bamboo pieces together to form a board; the board structure is the same as that of Example 1; adjacent boards are connected together by a second adhesive, and a mesh is laid on the connection interface, and the mesh can be selected from glass fiber mesh; wherein the first adhesive is selected from phenolic resin, and the first adhesive is mixed with 30wt% of palm fiber, and the average length of the palm fiber is 2.5-3cm; the second adhesive is selected from phenolic resin; S4. The assembled board blanks are placed into a hot press for forming and hot pressing. The hot pressing pressure is 2.5 MPa, the hot pressing temperature is 140° C., and the hot pressing time is 4 min. Finally, the board blanks are cut to obtain the plywood of the present application.

[0024] Example 3 A method for preparing a bamboo anti-cracking plywood comprises the following steps: S1. Slice: Select 5-year-old bamboos that are free of insects and straight in shape, and process them into strips; S2, using a rough milling machine to remove the green and yellow of the bamboo slices; then steaming the roughly milled bamboo strips; drying the steamed bamboo slices at 35°C and keeping ventilation to a moisture content of 8-12%; using a carbonization furnace, pressurizing saturated steam to 2 atmospheric pressures, temperature conditions: 140°C, for carbonization; then drying the carbonized bamboo slices again; and then fine milling the length, width and thickness to obtain the bamboo slices of the present application; S3, using a roughening device to roughen the surface of the bamboo pieces, the roughened area accounts for about 30% of the surface area of ​​the bamboo pieces; then using the first adhesive to bond the bamboo pieces together to form a board; the board structure is the same as that of Example 1; adjacent boards are connected together by a second adhesive, and a mesh is laid on the connection interface, and the mesh can be selected from glass fiber mesh; wherein the first adhesive is selected from phenolic resin, and the first adhesive is mixed with 40wt% of palm fiber, and the average length of the palm fiber is 2.5-3cm; the second adhesive is selected from phenolic resin; S4. The assembled board blanks are placed into a hot press for forming and hot pressing. The hot pressing pressure is 2.5 MPa, the hot pressing temperature is 140° C., and the hot pressing time is 4 min. Finally, the board blanks are cut to obtain the plywood of the present application.

[0025] Example 4 The difference between this embodiment and embodiment 1 is that no roughening equipment is used to roughen the bamboo pieces, and the remaining steps and components are the same.

[0026] Example 5 The difference between this embodiment and embodiment 1 is that when the bamboo pieces are distributed, the surface layer and the adjacent inner layer are in contact with each other, and the other steps and components are the same.

[0027] Example 6 The difference between this embodiment and embodiment 1 is that the palm fibers are replaced by an equal amount of polyester fibers, and the remaining steps and components are the same.

[0028] Comparative Example 1 The difference between this embodiment and embodiment 1 is that no palm fiber is added to the first adhesive, and the remaining steps and components are the same.

[0029] Comparative Example 2 The difference between this embodiment and embodiment 1 is that no mesh layer is provided between the plates, and the remaining steps and components are the same.

[0030] Performance Testing Refer to the method 4.40 Determination of surface resistance to cold and hot cycling performance-Method 1 in GBT17657-2022 "Test methods for physical and chemical properties of wood-based panels and veneered wood-based panels" for testing, and then observe whether there are cracks or bubbles on the surface of the specimen.

[0031] Refer to GBT21128-2007GBT 21128-2007 "Structural bamboo-wood composite panels" to test the horizontal shear strength of the sample.

[0032] Table 1 Performance test table of Examples 1-6 and Comparative Examples 1-2 Surface cracking Horizontal shear strength Example 1 No cracks, no bubbles 3.2MPa Example 2 No cracks, no bubbles 3.6MPa Example 3 No cracks, no bubbles 3.5MPa Example 4 Minor cracks, no bubbles 3.1MPa Example 5 Minor cracks, no bubbles 2.8MPa Example 6 No cracks, no bubbles 3.2MPa Comparative Example 1 More cracks, some bubbles 2.6MPa Comparative Example 2 Minor cracks, minor bubbles 2.5MPa By comparing Example 1 with Examples 4, 5, and 6, it can be seen that after the surface of the bamboo pieces is roughened, the stress points of the palm fibers are greatly increased, and the palm fibers can form a grid-like structure in the plywood, thereby improving the anti-cracking performance and mechanical properties of the plywood; and the distribution of the bamboo pieces has a certain influence on the cracking performance and mechanical properties. By comparing Example 1 with Comparative Examples 1 and 2, it can be seen that both the palm fibers and the mesh cloth are very helpful to the cracking performance and mechanical properties of the plywood.

[0033] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A bamboo anti-cracking plywood, characterized in that: It comprises a multi-layer board body, each layer of which is made of bamboo pieces by using a first adhesive, wherein the first adhesive comprises fiber filaments with a mass fraction of 20-40%; adjacent boards are connected by a second adhesive, and mesh cloth is arranged between adjacent boards.

2. The bamboo anti-cracking plywood according to claim 1, characterized in that: The average length of the fiber filaments is 1.5-3 cm.

3. The bamboo anti-cracking plywood according to claim 1, characterized in that: The first adhesive and the second adhesive are independently selected from one or more of urea-formaldehyde resin, phenol-formaldehyde resin and melamine-formaldehyde resin.

4. The bamboo anti-cracking plywood according to claim 3, characterized in that: Before using the bamboo slices, the surface of the bamboo slices is roughened using a roughening device.

5. The bamboo anti-cracking plywood according to claim 4, characterized in that: The surface roughening treatment area ratio of the bamboo slices is 30-45%.

6. The bamboo anti-cracking plywood according to claim 5, characterized in that: The bamboo pieces have an epidermis layer and an inner layer. When a plurality of the bamboo pieces are connected together, the epidermis layers are in contact with each other, and the inner layers are in contact with each other.

7. The bamboo anti-cracking plywood according to claim 1, characterized in that: The fiber yarn is selected from one of natural palm fiber and artificial fiber.

8. A method for preparing the bamboo anti-cracking plywood according to claim 4, characterized in that: The following steps are involved: S1. Cutting: Select bamboo and process it into strips; S2, sequentially performing rough milling, steaming, drying, carbonizing, drying, and fine milling to obtain bamboo chips of length, width, and thickness; S3, roughening the surface of the bamboo pieces using a roughening device, and then bonding the bamboo pieces together using a first adhesive; bonding the upper and lower plates together using a second adhesive and a mesh cloth; S4, loading into a hot press machine for hot pressing and then cutting.

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