A method for preparing waterproof and moisture-proof thin density board

Abstract

The present invention discloses a method for preparing a waterproof and moisture-proof thin density board, which relates to the technical field of sealed board production technology, and includes the following steps: pulping: hot grinding and steaming wood fibers to obtain wood fiber slurry; mixing; pressing board embryos; preparing a waterproof film: preparing a protective film adapted to the board embryo obtained in S3 through a mold, performing a multi-pore surface treatment on the protective film, and applying a waterproofing agent to the lower surface of the protective film, and attaching a layer of sealing film coating on the upper surface of the protective film to obtain a waterproof film composed of a waterproofing agent layer, a protective film and a sealing film coating; board making; processing. The present invention has a reasonable structure, not only by mixing slurry with waterproofing agent to fill the original fiber pores of the fiberboard itself, but also by hot-melting a more effective waterproof film is fixed on the outer side of the board, so that the waterproof and moisture-proof effect prepared by this process is better and the service life is longer.

Description

Technical Field

[0001] The invention relates to the technical field of sealing board production technology, and in particular to a method for preparing a waterproof and moisture-proof thin density board. Background Art

[0002] Fiberboard is a kind of man-made board, which is mainly made of wood fiber or other plant fiber. Wood, branches and other objects are soaked in water, crushed and pressed, and adhesive is applied. After fiber separation, molding, hot pressing and other processes, the man-made board is made. At present, the fiberboard on the market is roughly divided into hard density fiberboard, medium density fiberboard and soft fiberboard (low density fiberboard) according to density. Among them, medium density fiberboard is widely used as interior decoration material, furniture and other purposes.

[0003] Since there are often a lot of pores on the surface of wood fibers, water molecules in the air are easily adsorbed in the fiber gaps in humid air, causing the fiberboard to change in size and deform. Therefore, medium-density fiberboard is generally required to have a certain waterproof and moisture-proof function.

[0004] At present, in order to improve the water resistance of fiberboard, waterproofing agents are usually applied in the production of fiberboard. The waterproofing agents are adsorbed on the fiber surface to block some gaps in the fiber, cut off the water transmission channel, and play a waterproofing role. However, the existing waterproofing agents generally use non-polar materials, such as paraffin or rosin and other hydrophobic substances. Therefore, the combination of waterproofing agents and the fiberboard surface is often physical adsorption, and the bonding strength is limited, which leads to cracking and falling off after long-term use. At the same time, long-term contact with water vapor in the air will also affect the bonding effect with the fiber surface, resulting in loss of waterproofing effect. Therefore, the service life of the fiber sealing board under this process is relatively short.

[0005] To this end, the present application provides a method for preparing a waterproof and moisture-proof thin density board to solve the above technical problems. Summary of the invention

[0006] The purpose of the present application is to provide a method for preparing a waterproof and moisture-proof thin density board, which not only fills the original fiber pores of the fiberboard itself with waterproof agent by mixing slurry with waterproof agent, but also fixes a more effective waterproof film on the outside of the board by hot melting, so that the waterproof and moisture-proof effect prepared by this process is better and the service life is longer.

[0007] To achieve the above purpose, the present application provides the following technical solution: a method for preparing a waterproof and moisture-proof thin density board, comprising the following steps:

[0008] S1, pulping: hot grinding and cooking of wood fiber to obtain wood fiber pulp;

[0009] S2, mixing: mixing a waterproofing agent with a mass fraction of 2-3% into the wood fiber slurry obtained in S1, and adding a corresponding curing agent, stirring and mixing, and obtaining a mixed slurry;

[0010] S3, pressing a board embryo: drying the mixed slurry in S2 to prepare dry fibers, and pressing the dry fibers to prepare a board embryo;

[0011] S4, preparing a waterproof film: preparing a protective film adapted to the board blank obtained in S3 by a mold, performing a surface porous treatment on the protective film, applying a waterproofing agent to the lower surface of the protective film, and attaching a layer of sealing film coating to the upper surface of the protective film to obtain a waterproof film consisting of a waterproofing agent layer, a protective film and a sealing film coating;

[0012] S5, board making: attaching the protective film obtained in S4 to the surface of the board blank, placing it in a high temperature environment for high pressure molding, and repeating this operation to hot-press the protective film on the other side of the board blank, thereby making a substrate;

[0013] S6, processing: trimming the substrate obtained in S5, and waxing and polishing the surfaces on both sides thereof to obtain a final waterproof and moisture-proof density board body.

[0014] As a further preferred embodiment, in S1, after the wood fiber is subjected to hot grinding and steaming, a hot grinder is used to perform hot grinding and defibration, thereby obtaining wood fiber pulp.

[0015] As a further preferred embodiment, the curing agent in S2 includes melamine-modified urea-formaldehyde resin glue and ammonium chloride curing agent.

[0016] As a further preferred embodiment, the amount of the melamine modified urea-formaldehyde resin adhesive added is 10% to 12% of the total fiber weight, and the amount of ammonium chloride added is 1% of the weight of the melamine modified urea-formaldehyde resin adhesive.

[0017] As a further preferred embodiment, the drying temperature of the mixed slurry in S2 in S3 is 100 to 200 degrees Celsius, and the dried dry fibers are laid into a board shape, and are pressurized at a pressure of at least 3 MPa at an environment of 190-210 degrees Celsius to form a board embryo.

[0018] As a further preferred solution, the moisture content of the dry fibers in S3 is maintained at 5-7%.

[0019] As a further preferred embodiment, the protective film in S4 is a polymer nano-repair coating, which is formed by spraying a mixture of synthetic polymer resins including acrylic acid, polyurethane, PU, ​​PUR, hardener, solvent, and additives, and uniformly covering both sides of the PVC base film to form a protective film.

[0020] As a further preferred solution, the protective film is subjected to pore distribution treatment using a mold so that its surface is densely covered with fine pores for accommodating the waterproofing agent.

[0021] As a further preferred solution, the sealing film coating is a PVC-based film and is not subjected to pore treatment.

[0022] As a further preferred solution, the plate making process of S5 includes:

[0023] S501, fixing the blank: fixing the blank on a bracket, placing the bracket in the lower half of the box of the hot-melt pressurizing device, and controlling the bracket to rise and fall by a lifting device, so that the bracket can dock with the middle opening of the hot-melt pressurizing device to form a seal, so that the blank can protrude above a horizontal line based on the middle level of the hot-melt pressurizing device;

[0024] S502, fixing the protective film: horizontally erecting and fixing the protective film on the middle horizontal line of the box of the hot-melt pressurizing device, so that when the blank protrudes above the horizontal line, the protective film can be closely attached to the upper surface of the blank;

[0025] S503, hot melt pressurization: a descendable cover is arranged on the upper half of the box of the hot melt pressurization equipment, a heating device is arranged inside the cover, and an external air compressor is connected to make the cover descend to cooperate with the bracket for fixing the blank, so that after the protective film and the blank are placed inside the cover, the heating device can be used to heat the inside of the cover, and the air compressor can be used to increase the pressure inside the cover, and the protective film is fixed to the upper surface of the blank by using an air pressure of at least 3Mpa;

[0026] S504, repeat the above steps S501, S502 and S503 to fix the protective film on the lower surface of the board blank.

[0027] In summary, the technical effects and advantages of the present invention are as follows:

[0028] The present invention prepares a new waterproof membrane to cooperate with the substrate to form a waterproof and moisture-proof protective layer. Compared with the traditional medium-density fiberboard, the density board prepared by the present application not only fills the original fiber pores of the fiberboard itself with waterproof agent by mixing slurry and waterproof agent, but also fixes a more effective waterproof membrane on the outside of the board by hot melting, so that the waterproof and moisture-proof effect prepared by this process is better and the service life is longer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 A schematic diagram of a process for preparing a waterproof and moisture-proof thin density board;

[0031] Figure 2 A schematic diagram of the process of preparing a waterproof and moisture-proof thin density board in step S5;

[0032] Figure 3 The schematic diagram of the S5 board making principle of the method for preparing the waterproof and moisture-proof thin density board;

[0033] Figure 4 The present invention is a schematic structural diagram of a waterproof and moisture-proof thin density board obtained by a method for preparing the waterproof and moisture-proof thin density board.

[0034] In the figure: 1. Lower half of the hot melt pressurizing equipment; 101. Horizontal opening in the middle of the hot melt pressurizing equipment; 2. Lifting device; 3. Bracket body; 4. Plate embryo body; 5. Waterproof membrane body; 501. Protective membrane body; 502. Sealing membrane body; 6. Cover body; 7. Heating device; 8. Air compressor. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Example: Reference Figure 1 The method for preparing a waterproof and moisture-proof thin density board shown in the figure comprises the following steps:

[0037] S1. Pulping: The wood fiber is subjected to hot grinding and steaming, and then hot grinding and defibration by a hot mill to obtain wood fiber pulp.

[0038] S2, mixing: the wood fiber slurry obtained in the above S1 is mixed with a water-proofing agent with a mass fraction of 2-3%. The water-proofing agent in this embodiment comprises 20-25 parts of emulsified paraffin, 10-15 parts of terminal hydroxyl polydimethylsiloxane and 3-5 parts of silane coupling agent, wherein the silane coupling agent can be γ-aminopropyl triethoxysilane, and specifically, γ-aminopropyl triethoxysilane and ethanol solution are mixed and stirred at a mass ratio of 1:20, the pH value is adjusted to 4-5, water is added dropwise at a molar ratio of γ-aminopropyl triethoxysilane to water of 1:2, the temperature is raised to 75-80°C for reaction for 1-2h, the pH value is adjusted to 7, and the reaction mixture is subjected to low-boiling substances at a temperature of 80°C and a vacuum degree of 0.1MPa to obtain a hydrolyzate; the emulsified paraffin is placed in a reactor and stirred, and the temperature is raised to 90-100°C, and then the terminal hydroxyl polydimethylsiloxane and the hydrolyzate are added and mixed and stirred to obtain the water-proofing agent. In specific implementation, the above-mentioned waterproofing agent is an existing disclosed technology, and the present application may also adopt other types of waterproofing agents commonly used in the field of density board preparation, which is not limited here.

[0039] After the waterproofing agent is mixed, a curing agent is added accordingly, and the mixture is stirred and mixed to obtain a mixed slurry. Specifically, in this embodiment, the curing agent used includes but is not limited to melamine modified urea-formaldehyde resin glue and ammonium chloride curing agent, and the amount of melamine modified urea-formaldehyde resin glue added is 10% to 12% of the total fiber weight, and the amount of ammonium chloride added is 1% of the weight of the melamine modified urea-formaldehyde resin glue.

[0040] S3, pressing the board embryo: drying the mixed slurry in S2. In this embodiment, the drying temperature is 100 to 200 degrees Celsius to make dry fibers, and the moisture content of the dry fibers is maintained at about 5-7%. The fibers are laid into a board shape and pressurized at a pressure of at least 3 MPa at an environment of 190-210 degrees Celsius to form a board embryo.

[0041] S4, preparation of waterproof film: a protective film adapted to the blank obtained in S3 is prepared by a mold, and the surface of the protective film is pore-dressed by the mold so that the surface is densely covered with fine pores for accommodating the subsequent waterproofing agent. In specific implementation, in this embodiment, the protective film is a polymer nano-repair coating, which is a mixture of synthetic polymer resins including acrylic acid, polyurethane, PU, ​​and PUR, mixed with a hardener, a solvent, and an additive, and a PVC base film can be selected, which is placed on the mold, and the polymer nano-repair coating is evenly covered on both sides of the PVC base film by spraying, thereby forming a protective film.

[0042] Subsequently, the waterproofing agent can be applied to the lower surface of the protective film, and a layer of sealing film coating can be attached to the upper surface of the protective film to obtain a waterproofing film consisting of a waterproofing agent layer, a protective film and a sealing film coating. The sealing film here can also be made of a PVC base film, but without pore treatment, so that the waterproofing film will not be water permeable.

[0043] S5, board making: attaching the protective film obtained in S4 to the surface of the board blank, placing it in a high temperature environment for high pressure molding, and repeating this operation to hot-press the protective film on the other side of the board blank, thereby making a substrate.

[0044] For specific operations, please refer to Figure 2 and Figure 3 , and with the help of the accompanying drawings in the specification, the board making process includes:

[0045] S501, fix the plate embryo: fix the plate embryo body 4 to the upper end surface of the bracket body 3, and place the bracket in the lower half box 1 of the hot melt pressurizing device, the lower half box 1 of the hot melt pressurizing device is provided with a lifting device 2, the lifting device 2 is a cylinder or an electric push-pull rod, and the lifting device 2 can be used to control the bracket body 3 to drive the plate embryo body 4 to move up and down, and the middle of the hot melt pressurizing device is provided with a hot melt pressurizing device middle horizontal line opening 101, which can be connected with the upper end surface edge of the bracket body 3 to form a seal, so that the plate embryo body 4 can protrude above the hot melt pressurizing device middle horizontal line opening 101;

[0046] S502, fixing the protective film: horizontally erecting and fixing the waterproof film body 5 on the middle horizontal line of the box of the hot melt pressurizing device, so that when the board embryo body 4 protrudes above the opening 101 of the middle horizontal line of the hot melt pressurizing device, the waterproof film body 5 can be closely attached to the upper surface of the board embryo body 4;

[0047] S503, hot melt pressurization: a descendable cover body 6 is arranged on the upper half of the box of the hot melt pressurization equipment, and a heating device 7 is arranged inside the cover body 6. The heating device 7 can be selected from but not limited to a long-distance infrared heater, and the upper end surface of the cover body 6 is also equipped with a lifting device 2 for lifting and lowering by a controller, and an air compressor 8 connected to the inside thereof. Therefore, when the cover body 6 descends and cooperates with the horizontal opening 101 in the middle of the hot melt pressurization equipment and the bracket body 3 to place the waterproof membrane body 5 and the board embryo body 4 inside the cover body 6, the heating device 7 can be used to heat the inside of the cover body 6, and the air compressor 8 can be used to increase the internal pressure of the cover body 6, and the air pressure of at least 3Mpa is used to fix the waterproof membrane body 5 on the upper surface of the board embryo;

[0048] S504 , repeat the above S501 , S502 and S503 to fix the waterproof membrane body 5 to the lower surface of the slab body 4 .

[0049] In this process, the waterproof membrane body 5 includes a protective membrane body 501 and a sealing membrane body 502 disposed outside the protective membrane body 501. Therefore, the substrate structure controlled by this process is as follows: Figure 4 As shown, the sealing film body 502 is located at the outermost side and can be torn off without affecting the waterproof and moisture-proof effects.

[0050] S6, processing: trimming the substrate obtained in S5, and waxing and polishing the surfaces on both sides thereof, so as to obtain the final waterproof and moisture-proof density board body.

[0051] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a waterproof and moisture-proof thin density board, characterized in that: The following steps are involved: S1, pulping: hot grinding and cooking of wood fiber to obtain wood fiber pulp; S2, mixing: mixing a waterproofing agent with a mass fraction of 2-3% into the wood fiber slurry obtained in S1, and adding a corresponding curing agent, stirring and mixing, to obtain a mixed slurry; S3, pressing a board embryo: drying the mixed slurry in S2 to prepare dry fibers, and pressing the dry fibers to prepare a board embryo; S4, preparing a waterproof film: preparing a protective film adapted to the board blank obtained in S3 by a mold, performing a surface porous treatment on the protective film, applying a waterproofing agent to the lower surface of the protective film, and attaching a layer of sealing film coating to the upper surface of the protective film to obtain a waterproof film consisting of a waterproofing agent layer, a protective film and a sealing film coating; S5, board making: attaching the waterproof film obtained in S4 to the surface of the board blank, placing it in a high temperature environment for high pressure molding, and repeating this operation to hot-press the waterproof film on the other side of the board blank, thereby making a substrate; S6, processing: trimming the substrate obtained in S5, and waxing and polishing the surfaces on both sides thereof to obtain a final waterproof and moisture-proof density board body; The sealing film coating is a PVC base film and is not subjected to pore treatment; The S5 board making process includes: S501, fixing the blank: fixing the blank on a bracket, placing the bracket in the lower half of the box of the hot-melt pressurizing device, and controlling the bracket to rise and fall by a lifting device, so that the bracket can dock with the middle opening of the hot-melt pressurizing device to form a seal, so that the blank can protrude above a horizontal line based on the middle level of the hot-melt pressurizing device; S502, fixing the waterproof membrane: horizontally erecting and fixing the waterproof membrane on the horizontal line in the middle of the box of the hot-melt pressurizing equipment, so that when the slab is protruding above the horizontal line, the waterproof membrane can be closely attached to the upper surface of the slab; S503, hot melt pressurization: a descendable cover is arranged on the upper half of the box of the hot melt pressurization equipment, a heating device is arranged inside the cover, and an external air compressor is connected to make the cover descend to cooperate with the bracket for fixing the slab blank, so that after the waterproof film and the slab blank are placed inside the cover, the heating device can be used to heat the inside of the cover, and the air compressor can be used to increase the pressure inside the cover, and the waterproof film is fixed to the upper surface of the slab blank by using an air pressure of at least 3Mpa; S504, repeat the above steps S501, S502 and S503 to fix the waterproof membrane on the lower surface of the slab.

2. The method for preparing a waterproof and moisture-proof thin density board according to claim 1, characterized in that: In S1, after the wood fiber is subjected to hot grinding and steaming, a hot grinding mill is used to perform hot grinding and defibration, thereby obtaining wood fiber pulp.

3. The method for preparing a waterproof and moisture-proof thin density board according to claim 1, characterized in that: The curing agent in S2 includes melamine-modified urea-formaldehyde resin glue and ammonium chloride curing agent.

4. The method for preparing a waterproof and moisture-proof thin density board according to claim 3, characterized in that: The added amount of the melamine modified urea-formaldehyde resin adhesive is 10% to 12% of the total fiber weight, and the added amount of ammonium chloride is 1% of the weight of the melamine modified urea-formaldehyde resin adhesive.

5. The method for preparing a waterproof and moisture-proof thin density board according to claim 1, characterized in that: In S3, the mixed slurry in S2 is dried at a temperature of 100 to 200 degrees Celsius, and the dried dry fibers are laid into a board shape, and are pressurized at a pressure of at least 3 MPa at an environment of 190-210 degrees Celsius to form a board embryo.

6. The method for preparing a waterproof and moisture-proof thin density board according to claim 1, characterized in that: The moisture content of the dry fibers in S3 is maintained at 5-7%.

7. The method for preparing a waterproof and moisture-proof thin density board according to claim 1, characterized in that: The protective film in S4 is a polymer nano-repair coating.

8. The method for preparing a waterproof and moisture-proof thin density board according to claim 7, characterized in that: The protective film is subjected to pore distribution treatment using a mold, so that its surface is densely covered with fine pores for accommodating the waterproofing agent.

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