Moisture-proof plywood and method for manufacturing the same

Abstract

The present application relates to a kind of moisture-proof plywood and its preparation method, belong to plywood processing technical field, moisture-proof plywood is obtained by gluing by veneer, the number of the veneer is three layers, and the fiber direction of adjacent layer veneer is perpendicular to each other;The adhesive is composed of liquid adhesive and filler;Wherein, according to weight parts, the preparation raw material of the liquid adhesive includes: 40-45 parts of isocyanate, 6-12 parts of dioctyl phthalate, 3-6 parts of triethyl orthoformate, 12-16 parts of epoxy soybean oil and 1-3 parts of polydimethylsiloxane;The preparation raw material of the filler includes: 35-55 parts of wood powder, 10-20 parts of calcium carbonate, 30-35 parts of aluminum stearate and 5-10 parts of carbon nanotube.The fiber direction of adjacent layer veneer is perpendicular to each other, can prevent veneer from fiber direction place fracture, the way of liquid adhesive and filler combination is used to prepare adhesive, and the filler provides skeleton for liquid adhesive, can control the viscosity, flow leveling property and other construction performance of adhesive.

Description

Technical Field

[0001] This invention belongs to the field of plywood processing technology, specifically relating to a moisture-proof plywood and its preparation method. Background Technology

[0002] Plywood is a three- or multi-layered sheet material made by rotary cutting logs into veneers or slicing timber into thin sheets and then gluing them together with adhesives. It usually uses an odd number of veneer layers and glues the adjacent veneer layers with the fiber directions perpendicular to each other.

[0003] Traditional plywood is generally bonded with urea-formaldehyde resin. Urea-formaldehyde resin is prone to hydrolysis when it comes into contact with water or in humid environments, which can lead to the failure of the adhesive layer. If plywood is used to package products that are susceptible to moisture, the failure of the adhesive layer can cause the plywood to crack, allowing the products inside to become damp. Summary of the Invention

[0004] The purpose of this invention is to provide a moisture-proof plywood and its preparation method in order to solve the above-mentioned problems.

[0005] The present invention achieves the above objectives through the following technical solutions: This invention provides a moisture-proof plywood, which is obtained by gluing veneers together with an adhesive. The number of veneers is three layers, and the fiber directions of adjacent veneers are perpendicular to each other. The adhesive consists of a liquid adhesive and a filler; The raw materials for preparing the liquid adhesive, by weight, include: 40-45 parts isocyanate, 6-12 parts dioctyl phthalate, 3-6 parts triethyl orthoformate, 12-16 parts epoxidized soybean oil, and 1-3 parts polydimethylsiloxane; the raw materials for preparing the filler include: 35-55 parts wood flour, 10-20 parts calcium carbonate, 30-35 parts aluminum stearate, and 5-10 parts carbon nanotubes.

[0006] As a further optimization of the present invention, the preparation process of the liquid adhesive is as follows: (1) Put dioctyl phthalate, triethyl orthoformate and epoxidized soybean oil into a dry and clean container and stir at 300-500 r / min for 15 min to obtain the base liquid; (2) Stir the base liquid continuously at a stirring speed of 150-180 r / min, add isocyanate dropwise, stir at 300-400 r / min for 20 min, and after stirring is finished, adjust the stirring speed to 80-120 r / min, add polydimethylsiloxane, stir at 80-120 r / min for 20 min to obtain the preform. (3) Transfer the pre-made material to a sealed container and let it stand for 30-45 minutes to obtain liquid adhesive.

[0007] As a further optimization of the present invention, the preparation process of the filler is as follows: (1) Calcium carbonate, aluminum stearate and carbon nanotubes are put into a dry and clean container, stirred at 60-80 r / min for 15 min, and ground to 50-100 nm to obtain a mixed powder; (2) Mix wood powder with mixed powder and ultrasonically vibrate for 20-40 minutes to couple the pores and obtain the filler.

[0008] As a further optimization of the present invention, the raw materials for preparing wood flour, by weight, include: 30-35 parts of paulownia wood, 20-45 parts of Masson pine wood, 15-30 parts of silver poplar wood and 35-55 parts of Japanese cedar wood.

[0009] As a further optimization of the present invention, the preparation process of wood flour is as follows: (1) Remove the bark from the paulownia wood, pine wood, silver poplar wood and cedar wood, and break them into wood chips that are 20-30 mm long and 5-10 mm wide; (2) Dry at 80-120℃ to a moisture content of 3-8%, and pulverize to 75-180μm to obtain wood flour.

[0010] As a further optimization of the present invention, the adhesive is composed of liquid adhesive and filler. The specific preparation process of the adhesive is as follows: the adhesive is continuously stirred at 60-80 r / min in an environment of 60°C, and the filler is added at the 15th minute of stirring. The mixture is stirred until it is evenly dispersed to obtain the adhesive.

[0011] This invention also provides a method for preparing moisture-proof plywood, comprising the following steps: (1) Prepare three veneers, take one of them as the middle layer veneer, apply adhesive to both sides of the middle layer veneer, and cover the upper and lower veneers with the fiber direction perpendicular to the middle layer veneer to form a blank; (2) The assembled slab is fed into a cold press and pressed at 0.5-1.5 MPa for 15-30 minutes to obtain a pre-formed slab; (3) Apply 1.5 - 2.5 MPa to the pre-formed board at 180-220℃, stop applying pressure after 15-35 minutes, and allow it to cool naturally to obtain moisture-proof plywood.

[0012] As a further optimization of the present invention, the thickness of the single board is 2.5mm.

[0013] As a further optimization of the present invention, the amount of adhesive applied to one side of the moisture-proof plywood is 300-330 g / m². 2 .

[0014] The beneficial effects of this invention are as follows: The moisture-proof plywood of this invention is obtained by gluing veneers together with an adhesive. The fiber directions of adjacent veneer layers are perpendicular to each other, which can prevent the veneers from breaking at the fiber direction. The adhesive is prepared by combining liquid adhesive and filler. The filler provides a skeleton for the liquid adhesive and can control the viscosity, leveling and other construction properties of the adhesive. In the preparation of the filler, ultrasonic vibration is used to achieve pore coupling between the mixed powder and wood flour. This means that the mixed powder can deeply penetrate and anchor in the micropores of the wood flour, reducing the generation of air bubbles and greatly increasing the contact area and mechanical interlocking force between the adhesive and the wood, thereby significantly improving the bonding strength. Detailed Implementation

[0015] The present application will now be described in further detail. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0016] Unless otherwise specified, all methods used in this invention are conventional methods known to those skilled in the art, and all reagents and materials used are commercially available products.

[0017] In this invention, the moisture-proof plywood is obtained by gluing veneers together with an adhesive. The number of veneers is three layers, and the fiber directions of adjacent veneers are perpendicular to each other.

[0018] All three layers of veneer are made of poplar wood.

[0019] Example 1 The preparation process of liquid adhesive is as follows: Add 6 parts of dioctyl phthalate, 3 parts of triethyl orthoformate and 12 parts of epoxidized soybean oil into a dry and clean container, stir at 300 r / min for 15 min to obtain the base liquid; The base liquid was continuously stirred at a stirring speed of 150 r / min, 40 parts of isocyanate were added dropwise, and the mixture was stirred at 300 r / min for 20 min. After stirring, the stirring speed was adjusted to 80 r / min, 1 part of polydimethylsiloxane was added, and the mixture was stirred at 80 r / min for 20 min to obtain the preform. Transfer the pre-formulated material to a sealed container and let it stand for 30 minutes to obtain a liquid adhesive; The preparation process of the filler is as follows: Add 10 parts calcium carbonate, 30 parts aluminum stearate and 5 parts carbon nanotubes into a dry and clean container, stir at 60-80 r / min for 15 min, and grind to 50 nm to obtain a mixed powder. 35 parts of wood flour were mixed with the mixed powder and ultrasonically vibrated for 20 minutes to couple the pores, thus obtaining the filler; The preparation process of wood flour is as follows: Remove the bark from 30 parts of paulownia wood, 20 parts of Masson pine wood, 15 parts of silver poplar wood and 35 parts of Japanese cedar wood, and break them into wood chips 20 mm long and 5 mm wide. The wood flour was dried at 80℃ to a moisture content of 3% and then pulverized to 75μm. The specific preparation process of the adhesive is as follows: The adhesive was continuously stirred at 60 r / min at 60℃. The filler was added at the 15th minute of stirring, and the mixture was stirred until it was evenly dispersed to obtain the adhesive. The preparation process of moisture-proof plywood is as follows: Prepare three veneers (each veneer is 2.5mm thick). Take one of them as the middle layer veneer. Apply adhesive to both sides of the middle layer veneer (the adhesive application rate for moisture-resistant plywood is 300 g / m² on one side). 2 The upper and lower veneers are laid on the glued middle layer in a manner where the fiber direction is perpendicular to the middle veneer. The assembled slab is fed into a cold press and pressed at 0.5 MPa for 15 minutes to obtain a pre-formed slab. At 180℃, 1.5MPa is applied to the pre-formed slab. After 15 minutes, the pressure is stopped and the slab is allowed to cool naturally to obtain moisture-proof plywood.

[0020] Example 2 The preparation process of liquid adhesive is as follows: Add 9 parts of dioctyl phthalate, 4 parts of triethyl orthoformate and 14 parts of epoxidized soybean oil into a dry and clean container, stir at 400 r / min for 15 min to obtain the base liquid; The base liquid was continuously stirred at a stirring speed of 160 r / min, 42 parts of isocyanate were added dropwise, and the mixture was stirred at 350 r / min for 20 min. After stirring was completed, the stirring speed was adjusted to 100 r / min, 2 parts of polydimethylsiloxane were added, and the mixture was stirred at 100 r / min for 20 min to obtain the preform. Transfer the pre-formulated material to a sealed container and let it stand for 40 minutes to obtain a liquid adhesive; The preparation process of the filler is as follows: 15 parts calcium carbonate, 32 parts aluminum stearate and 8 parts carbon nanotubes were put into a dry and clean container, stirred at 70 r / min for 15 min and ground to 80 nm to obtain a mixed powder. 45 parts of wood flour were mixed with the mixed powder and ultrasonically vibrated for 30 minutes to couple the pores, thus obtaining the filler; The preparation process of wood flour is as follows: Bark was removed from 32 parts of paulownia wood, 35 parts of Masson pine wood, 23 parts of silver poplar wood, and 45 parts of Japanese cedar wood, and the wood chips were broken into pieces 25 mm long and 8 mm wide. The wood flour was dried at 100℃ to a moisture content of 5% and then pulverized to 120 μm. The specific preparation process of the adhesive is as follows: The adhesive was continuously stirred at 70°C for 60 minutes. The filler was added at the 15th minute of stirring and stirred until it was evenly dispersed to obtain the adhesive. The preparation process of moisture-proof plywood is as follows: Prepare three veneers (each veneer is 2.5mm thick). Take one of them as the middle layer veneer. Apply adhesive to both sides of the middle layer veneer (the adhesive application rate for moisture-resistant plywood is 320g / m² on one side). 2 The upper and lower veneers are laid on the glued middle layer in a manner where the fiber direction is perpendicular to the middle veneer. The assembled slab is fed into a cold press and pressed at 1 MPa for 21 minutes to obtain a pre-formed slab. At 200℃, a pressure of 2MPa is applied to the pre-formed board blank. After 25 minutes, the pressure is stopped and the board is allowed to cool naturally to obtain moisture-proof plywood.

[0021] Example 3 The preparation process of liquid adhesive is as follows: Add 12 parts of dioctyl phthalate, 6 parts of triethyl orthoformate and 16 parts of epoxidized soybean oil into a dry and clean container, stir at 500 r / min for 15 min to obtain the base liquid; The base liquid was continuously stirred at a stirring speed of 180 r / min, 45 parts of isocyanate were added dropwise, and the mixture was stirred at 400 r / min for 20 min. After stirring, the stirring speed was adjusted to 120 r / min, 3 parts of polydimethylsiloxane were added, and the mixture was stirred at 120 r / min for 20 min to obtain the preform. Transfer the pre-formulated material to a sealed container and let it stand for 45 minutes to obtain a liquid adhesive; The preparation process of the filler is as follows: Add 20 parts calcium carbonate, 35 parts aluminum stearate and 10 parts carbon nanotubes into a dry and clean container, stir at 80 r / min for 15 min, and grind to 100 nm to obtain a mixed powder. 55 parts of wood flour were mixed with a mixed powder and ultrasonically vibrated for 40 minutes to couple the pores, thus obtaining a filler. The preparation process of wood flour is as follows: 35 parts of paulownia wood, 45 parts of Masson pine wood, 30 parts of silver poplar wood and 55 parts of Japanese cedar wood were stripped of their bark and broken into wood chips 30 mm long and 10 mm wide. The wood flour was dried at 120℃ to a moisture content of 8% and then pulverized to 180μm. The specific preparation process of the adhesive is as follows: The adhesive was continuously stirred at 80 r / min at 60℃. The filler was added at the 15th minute of stirring and stirred until it was evenly dispersed to obtain the adhesive. The preparation process of moisture-proof plywood is as follows: Prepare three veneers (each veneer is 2.5mm thick). Take one of them as the middle layer veneer. Apply adhesive to both sides of the middle layer veneer (the adhesive application rate for moisture-resistant plywood is 330 g / m² on one side). 2 The upper and lower veneers are laid on the glued middle layer in a manner where the fiber direction is perpendicular to the middle veneer. The assembled slab is fed into a cold press and pressed at 1.5 MPa for 30 minutes to obtain a pre-formed slab. At 220℃, 2.5 MPa is applied to the pre-formed slab. After 5 minutes, the pressure is stopped and the slab is allowed to cool naturally to obtain moisture-proof plywood.

[0022] Comparative Example 1 The preparation process of liquid adhesive is as follows: Add 9 parts of dioctyl phthalate, 4 parts of triethyl orthoformate and 14 parts of epoxidized soybean oil into a dry and clean container, stir at 400 r / min for 15 min to obtain the base liquid; The base liquid was continuously stirred at a stirring speed of 160 r / min, 42 parts of isocyanate were added dropwise, and the mixture was stirred at 350 r / min for 20 min. After stirring was completed, the stirring speed was adjusted to 100 r / min, 2 parts of polydimethylsiloxane were added, and the mixture was stirred at 100 r / min for 20 min to obtain the preform. Transfer the pre-formulated material to a sealed container and let it stand for 40 minutes to obtain a liquid adhesive; The preparation process of the filler is as follows: 30 parts calcium carbonate, 47 parts aluminum stearate and 23 parts carbon nanotubes were put into a dry and clean container, stirred at 70 r / min for 15 min and ground to 80 nm to obtain the filler. The specific preparation process of the adhesive is as follows: The adhesive was continuously stirred at 70°C for 60 minutes. The filler was added at the 15th minute of stirring and stirred until it was evenly dispersed to obtain the adhesive. The preparation process of moisture-proof plywood is as follows: Prepare three veneers (each veneer is 2.5mm thick). Take one of them as the middle layer veneer. Apply adhesive to both sides of the middle layer veneer (the adhesive application rate for moisture-resistant plywood is 320g / m² on one side).2 The upper and lower veneers are laid on the glued middle layer in a manner where the fiber direction is perpendicular to the middle veneer. The assembled slab is fed into a cold press and pressed at 1 MPa for 21 minutes to obtain a pre-formed slab. At 200℃, a pressure of 2MPa is applied to the pre-formed board blank. After 25 minutes, the pressure is stopped and the board is allowed to cool naturally to obtain moisture-proof plywood.

[0023] Comparative Example 2 The preparation process of liquid adhesive is as follows: Add 9 parts of dioctyl phthalate, 4 parts of triethyl orthoformate and 14 parts of epoxidized soybean oil into a dry and clean container, stir at 400 r / min for 15 min to obtain the base liquid; The base liquid was continuously stirred at a stirring speed of 160 r / min, 42 parts of isocyanate were added dropwise, and the mixture was stirred at 350 r / min for 20 min. After stirring was completed, the stirring speed was adjusted to 100 r / min, 2 parts of polydimethylsiloxane were added, and the mixture was stirred at 100 r / min for 20 min to obtain the preform. Transfer the pre-formulated material to a sealed container and let it stand for 40 minutes to obtain a liquid adhesive; The preparation process of the filler is as follows: Bark was removed from 32 parts of paulownia wood, 35 parts of Masson pine wood, 23 parts of silver poplar wood, and 45 parts of Japanese cedar wood, and the wood chips were broken into pieces 25 mm long and 8 mm wide. The filler was dried at 100℃ to a moisture content of 5% and then pulverized to 120 μm. The specific preparation process of the adhesive is as follows: The adhesive was continuously stirred at 70°C for 60 minutes. The filler was added at the 15th minute of stirring and stirred until it was evenly dispersed to obtain the adhesive. The preparation process of moisture-proof plywood is as follows: Prepare three veneers (each veneer is 2.5mm thick). Take one of them as the middle layer veneer. Apply adhesive to both sides of the middle layer veneer (the adhesive application rate for moisture-resistant plywood is 320g / m² on one side). 2 The upper and lower veneers are laid on the glued middle layer in a manner where the fiber direction is perpendicular to the middle veneer. The assembled slab is fed into a cold press and pressed at 1 MPa for 21 minutes to obtain a pre-formed slab. At 200℃, a pressure of 2MPa is applied to the pre-formed board blank. After 25 minutes, the pressure is stopped and the board is allowed to cool naturally to obtain moisture-proof plywood.

[0024] Comparative Example 3 The preparation process of liquid adhesive is as follows: Add 9 parts of dioctyl phthalate, 4 parts of triethyl orthoformate and 14 parts of epoxidized soybean oil into a dry and clean container, stir at 400 r / min for 15 min to obtain the base liquid; The base liquid was continuously stirred at a stirring speed of 160 r / min, 42 parts of isocyanate were added dropwise, and the mixture was stirred at 350 r / min for 20 min. After stirring was completed, the stirring speed was adjusted to 100 r / min, 2 parts of polydimethylsiloxane were added, and the mixture was stirred at 100 r / min for 20 min to obtain the preform. Transfer the pre-formulated material to a sealed container and let it stand for 40 minutes to obtain a liquid adhesive; The preparation process of the filler is as follows: 15 parts calcium carbonate, 32 parts aluminum stearate and 8 parts carbon nanotubes were put into a dry and clean container, stirred at 70 r / min for 15 min and ground to 80 nm to obtain a mixed powder. 45 parts of wood flour were mixed with the mixed powder to obtain the filler; The preparation process of wood flour is as follows: Bark was removed from 32 parts of paulownia wood, 35 parts of Masson pine wood, 23 parts of silver poplar wood, and 45 parts of Japanese cedar wood, and the wood chips were broken into pieces 25 mm long and 8 mm wide. The wood flour was dried at 100℃ to a moisture content of 5% and then pulverized to 120 μm. The specific preparation process of the adhesive is as follows: The adhesive was continuously stirred at 70°C for 60 minutes. The filler was added at the 15th minute of stirring and stirred until it was evenly dispersed to obtain the adhesive. The preparation process of moisture-proof plywood is as follows: Prepare three veneers (each veneer is 2.5mm thick). Take one of them as the middle layer veneer. Apply adhesive to both sides of the middle layer veneer (the adhesive application rate for moisture-resistant plywood is 320g / m² on one side). 2 The upper and lower veneers are laid on the glued middle layer in a manner where the fiber direction is perpendicular to the middle veneer. The assembled slab is fed into a cold press and pressed at 1 MPa for 21 minutes to obtain a pre-formed slab. At 200℃, a pressure of 2MPa is applied to the pre-formed board blank. After 25 minutes, the pressure is stopped and the board is allowed to cool naturally to obtain moisture-proof plywood.

[0025] Performance testing (a) The moisture content of the moisture-proof plywood prepared by the methods in Examples 1-3 was tested according to the drying method in GB / T 9846-2015 "Ordinary Plywood". The test results are shown in Table 1.

[0026] Table 1

[0027] As can be seen from Table 1, the moisture content of the moisture-proof plywood prepared by the methods of Examples 1-3 is within the safe range, and the test samples prepared by the methods of Examples 1-3 are not prone to deformation, mold and cracking.

[0028] (II) The bonding strength of the moisture-proof plywood prepared by the methods of Examples 1-3 and Comparative Examples 1-3 was tested according to the drying method in GB / T 9846-2015 "Ordinary Plywood". All samples were pretreated according to Class I (weather-resistant plywood) as follows: boiling water for 4 hours → drying at (63±3)℃ for 20 hours → boiling water for 4 hours → cooling in water. After cooling, the samples were taken out for tensile testing until the adhesive layer was broken. The maximum breaking force was recorded and the strength was calculated. The test results are shown in Table 2.

[0029] Table 2

[0030] As can be seen from Table 2, the bonding strength of the moisture-proof plywood prepared by the methods of Examples 1-3 reaches an excellent level. During the testing process, it exhibits an extremely high "wood damage rate", which means that during the stress test, the damage mainly occurs in the wood fibers themselves, rather than the adhesive layer. This fully proves that its bonding strength not only meets the standard, but even exceeds the internal bonding force of the wood, ensuring the structural integrity and durability of the product. Even after undergoing the stringent pretreatment required by the methods in Examples 1-3, the moisture-resistant plywood prepared by these methods maintains stable bonding strength and exhibits an extremely low attenuation rate. This ensures that the plywood remains strong and does not delaminate or separate in humid environments with large temperature variations. The performance of Comparative Examples 1-3 was slightly inferior to that of Examples 1-3. It can be seen that in Examples 1-3, the wood flour was mixed with the mixed powder and ultrasonically vibrated for 40 minutes to couple the pores. The resulting filler had a synergistic effect in enhancing the bonding strength, increasing the strength of the plywood and making it less prone to deformation.

[0031] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A moisture-proof plywood, characterized in that, The moisture-proof plywood is made by gluing veneers together with adhesive. The number of veneers is three layers, and the fiber directions of adjacent veneers are perpendicular to each other. The adhesive consists of a liquid adhesive and a filler; The raw materials for preparing the liquid adhesive, by weight, include: 40-45 parts isocyanate, 6-12 parts dioctyl phthalate, 3-6 parts triethyl orthoformate, 12-16 parts epoxidized soybean oil, and 1-3 parts polydimethylsiloxane; the raw materials for preparing the filler include: 35-55 parts wood flour, 10-20 parts calcium carbonate, 30-35 parts aluminum stearate, and 5-10 parts carbon nanotubes. The raw materials for preparing the wood flour, by weight, include: 30-35 parts of paulownia wood, 20-45 parts of Masson pine wood, 15-30 parts of silver poplar wood and 35-55 parts of Japanese cedar wood; The preparation process of the wood flour is as follows: (1) Remove the bark from the paulownia wood, pine wood, silver poplar wood and cedar wood, and break them into wood chips that are 20-30 mm long and 5-10 mm wide; (2) Dry at 80-120℃ to a moisture content of 3-8%, and pulverize to 75-180μm to obtain wood flour; The preparation process of the filler is as follows: (1) Calcium carbonate, aluminum stearate and carbon nanotubes are put into a dry and clean container, stirred at 60-80 r / min for 15 min, and ground to 50-100 nm to obtain a mixed powder; (2) Mix wood powder with mixed powder and ultrasonically vibrate for 20-40 minutes to couple the pores and obtain a filler.

2. The moisture-proof plywood according to claim 1, characterized in that, The preparation process of the liquid adhesive is as follows: (1) Put dioctyl phthalate, triethyl orthoformate and epoxidized soybean oil into a dry and clean container and stir at 300-500 r / min for 15 min to obtain the base liquid; (2) Stir the base liquid continuously at a stirring speed of 150-180 r / min, add isocyanate dropwise, stir at 300-400 r / min for 20 min, and after stirring is finished, adjust the stirring speed to 80-120 r / min, add polydimethylsiloxane, stir at 80-120 r / min for 20 min to obtain the preform. (3) Transfer the pre-made material to a sealed container and let it stand for 30-45 minutes to obtain liquid adhesive.

3. The moisture-proof plywood according to claim 2, characterized in that, The adhesive is composed of liquid adhesive and filler. The specific preparation process of the adhesive is as follows: the adhesive is continuously stirred at 60-80 r / min in an environment of 60℃. The filler is added at the 15th minute of stirring and stirred until it is evenly dispersed to obtain the adhesive.

4. A method for preparing a moisture-proof plywood according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Prepare three veneers, take one of them as the middle layer veneer, apply adhesive to both sides of the middle layer veneer, and cover the upper and lower veneers with the fiber direction perpendicular to the middle layer veneer to form a blank; (2) The assembled slab is fed into a cold press and pressed at 0.5-1.5 MPa for 15-30 minutes to obtain a pre-formed slab; (3) Apply 1.5 - 2.5 MPa to the pre-formed board at 180-220℃, stop applying pressure after 15-35 minutes, and allow it to cool naturally to obtain moisture-proof plywood.

5. The method for preparing a moisture-proof plywood according to claim 4, characterized in that, The thickness of the single board is 2.5mm.

6. The method for preparing a moisture-proof plywood according to claim 4, characterized in that, The adhesive application rate for the moisture-proof plywood on one side is 300-330 g / m². 2 .

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