High-strength waterproof sheet and preparation method thereof

Abstract

The application discloses a kind of high-strength waterproof board and preparation method thereof, it is related to plate technical field.The preparation method of the application includes the following steps: sequentially stack 1 steel plate, 2 base plates, 1 fingerprint-resistant polymer film on 1 fingerprint-resistant polymer film, then heat pressing solidification, after cooling, plate is taken out, and high-strength waterproof board is obtained;Wherein, base plate is prepared from modified kraft paper and modified color paper.The water resistance, fire resistance and bonding strength of the plate are effectively improved by modifying kraft paper with modified phenolic resin, hydrophilic silicon dioxide and other components;The bonding strength, water resistance and fire resistance of the plate are further improved by modifying color paper with melamine, vanillin, flame retardant DOPO, 3,4-dihydroxybenzaldehyde and other components.Therefore, the application has a more extensive application prospect.

Description

Technical Field

[0001] This invention relates to the field of sheet technology, specifically to a high-strength waterproof sheet and its preparation method. Background Technology

[0002] Decorative panels are surface decoration materials used in construction, furniture, and interior decoration. They typically feature attractive textures, colors, or patterns, while also possessing certain physical properties such as wear resistance, crack resistance, and heat insulation. They are often used to enhance the decorative and functional properties of the substrate. Due to the nature of the material, it is difficult to achieve a microscopically smooth surface on steel panels. Although advancements in polishing and electroplating processes in recent years have resulted in ultra-matte, skin-like surface treatments, the presence of microscopic bumps still makes it difficult to avoid fingerprints or stains left after touching the panels, significantly impacting the tactile and visual appeal of high-end decorative panels.

[0003] To address the aforementioned issues, existing technologies propose a method of hot-pressing an anti-fingerprint polymer film onto the surface of the panel, which effectively solves the problem of poor fingerprint resistance. However, in practical applications, decorative panels still suffer from poor water resistance, easily absorbing water after prolonged immersion, leading to a significant decrease in adhesive strength; and relatively poor flame retardancy. Therefore, the water resistance and fire resistance of existing decorative panels still need improvement. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength waterproof board and its preparation method, thereby solving the following technical problems:

[0005] Existing decorative panels still suffer from poor water and fire resistance.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for preparing a high-strength waterproof board includes the following steps:

[0008] One steel plate, two base plates, and another anti-fingerprint polymer film are stacked on top of one anti-fingerprint polymer film. Then, hot pressing and curing are performed, and the board is removed after cooling to obtain a high-strength waterproof board.

[0009] The baseboard is prepared from modified kraft paper and modified colored paper.

[0010] Preferably, the preparation method of the base plate is as follows:

[0011] A1: Overlap 3-5 sheets of modified kraft paper, then heat-press and cure at 1-2MPa and 110-150℃ for 15-25 minutes, and then heat-press and cure at 1-2MPa and 155-165℃ for 10-20 minutes to obtain the kraft paper layer.

[0012] A2: Place one layer of kraft paper on top of one layer of modified colored paper, then place another layer of modified colored paper on top of the kraft paper, and then heat-press and cure at 1-2 MPa and 120-130℃ for 1-2 minutes to obtain the baseboard.

[0013] Preferably, the pressure during hot pressing curing is 8-12 MPa, the temperature is 150-170℃, and the duration is 20-60 min.

[0014] Preferably, the modified kraft paper is prepared using the following steps:

[0015] B1: Add montmorillonite to formaldehyde aqueous solution and perform ultrasonic dispersion at 17-21℃ for 2-4 hours with a power of 30-40W and a frequency of 55-60kHz. Then add phenol and sodium hydroxide aqueous solution and stir at 75-80℃ for 6-8 hours. Then add deionized water and anhydrous ethanol and stir for 30-60 minutes to obtain phenolic resin emulsion.

[0016] B2: Add p-benzenesulfonic acid to formaldehyde aqueous solution and stir for 20-30 min. Then add it to phenolic resin emulsion and stir at 65-75℃ for 2-4 h. Then centrifuge and wash the precipitate with deionized water 3-5 times and dry at 75-80℃ for 20-30 h to obtain phenolic resin prepolymer.

[0017] B3: Add phenolic resin prepolymer to deionized water and stir for 1-2 hours. Then add zirconium nitrate pentahydrate and stir for 20-24 hours. Then centrifuge and wash the precipitate with deionized water 3-5 times. Dry at 75-80℃ for 20-30 hours to obtain modified phenolic resin.

[0018] B4: Add anhydrous ethanol, modified phenolic resin, and hydrophilic silica to deionized water and perform ultrasonic treatment at a power of 100-300W and a frequency of 55-60kHz for 1-2 hours. Then immerse the mixture in kraft paper for 0.5-2 hours. After removing the paper, air dry it at 20-40℃ for 12-24 hours, and then dry it at 75-80℃ for 6-10 hours to obtain modified kraft paper.

[0019] Preferably, the mass ratio of formaldehyde aqueous solution, montmorillonite, phenol, sodium hydroxide aqueous solution, deionized water, and anhydrous ethanol in step B1 is 10.3-12.9:0.7-0.9:7.5-9.4:1.5-1.9:50-62.5:10-12.5;

[0020] The formaldehyde aqueous solution in step B1 has a mass fraction of 37%.

[0021] The mass fraction of the sodium hydroxide aqueous solution in step B1 is 2%;

[0022] In step B2, the mass ratio of formaldehyde aqueous solution, p-benzenesulfonic acid, and phenolic resin emulsion is 2.5-3.1:6-7:80-100.

[0023] The formaldehyde aqueous solution in step B2 has a mass fraction of 37%.

[0024] Preferably, the mass ratio of deionized water, phenolic resin prepolymer, and zirconium nitrate pentahydrate in step B3 is 100-200:5-10:6-12;

[0025] In step B4, the mass ratio of deionized water, anhydrous ethanol, modified phenolic resin, and hydrophilic silica is 50-100:50-100:5-10:2-6.

[0026] Preferably, the method for preparing the modified colored paper includes the following steps:

[0027] C1: Melamine, vanillin, and flame retardant DOPO are added to anhydrous ethanol and stirred at 70-75℃ for 40-60 min. Then, the temperature is raised to 90-95℃ and benzenesulfonic acid is added. The mixture is reacted at 90-95℃ for 8-12 h and then cooled to 20-35℃. The mixture is then poured into deionized water and stirred for 10-30 min. Finally, the mixture is filtered, washed, dried, and pulverized to obtain the synergistic powder.

[0028] C2: Under a nitrogen atmosphere, deionized water and melamine are mixed and stirred at 90-95℃ for 20-30 min. Then, 3,4-dihydroxybenzaldehyde is added and the pH is adjusted to 9 with a 5% sodium hydroxide aqueous solution. The mixture is reacted at 90-95℃ for 2-3 h, cooled to room temperature and filtered. The filtrate is removed by rotary evaporation under reduced pressure, washed 3-5 times with anhydrous ethanol, and dried to obtain modified melamine resin.

[0029] C3: Add synergistic powder to deionized water and perform ultrasonic treatment at a power of 30-40W and a frequency of 55-60kHz for 30-40 minutes. Then add modified melamine resin and stir at 60-70℃ for 20-30 minutes. Then immerse the colored paper in the mixture for 2-4 hours. After removing the paper, air dry it at 20-40℃ for 12-24 hours and then dry it at 75-80℃ for 4-10 hours to obtain the modified colored paper.

[0030] Preferably, the mass ratio of anhydrous ethanol, melamine, vanillin, flame retardant DOPO, benzenesulfonic acid, and deionized water in step C1 is 100-130: 8-10: 28-35: 28-35: 3-5: 300-500.

[0031] In step C2, the mass ratio of deionized water, melamine, and 3,4-dihydroxybenzaldehyde is 100-120: 2.1-2.5: 6.9-8.3.

[0032] Preferably, the mass ratio of deionized water, synergistic powder, and modified melamine resin in step C3 is 100-150:5:5-10.

[0033] The beneficial effects of this invention are:

[0034] This invention provides a high-strength waterproof board and its preparation method. The invention effectively improves the waterproof and fireproof properties of decorative panels through the following method.

[0035] (1) In the modified phenolic resin of this invention, montmorillonite can enhance the cohesive strength of the resin through physical entanglement and interfacial forces, inhibit crack propagation, and improve the brittleness of the phenolic resin. Benzenesulfonic acid can introduce polar functional groups, enhancing the interfacial bonding force between the resin and polar substrates such as paper fibers. In addition, sulfonic acid groups can participate in the later crosslinking reaction, forming a sulfonic acid-zirconium coordination structure, further increasing the crosslinking density and improving the heat resistance and chemical stability of the material. Zirconium nitrate pentahydrate hydrolyzes to generate zirconium hydroxide colloidal particles, which, through coordination, form an inorganic-organic hybrid network with the hydroxyl and sulfonic acid groups of the phenolic resin, significantly improving the thermal stability and mechanical strength of the resin, inhibiting the hydrolysis reaction, reducing water absorption, and improving water resistance. Phenolic resin easily forms a stable carbon layer at high temperatures, which blocks heat and oxygen transfer through the condensed phase flame retardant mechanism, inhibiting the spread of combustion. Montmorillonite in modified phenolic resin forms a "nano-barrier" within the resin. During combustion, its layered structure expands and melts into a dense char layer, delaying heat transfer to the substrate and inhibiting the escape of combustible gases. Montmorillonite's high thermal stability and ion exchange capacity also enhance the char layer strength, reduce molten dripping, and improve the material's refractory limit and thermal shock resistance. Zirconium nitrate pentahydrate decomposes at high temperatures to form zirconium oxide. Zirconium oxide's high melting point and chemical inertness prevent char layer cracking, inhibit flame penetration, and capture free radicals generated during combustion, slowing down the gas-phase combustion reaction rate. The combined effect of zirconium compounds and montmorillonite forms a "ceramicized char layer," possessing both barrier properties and high-temperature stability, significantly reducing the heat release rate and total heat release. The adsorption and catalytic effects of montmorillonite and zirconium compounds also reduce smoke generation and the release of toxic gases. When modified kraft paper layers and modified colored paper are cured by hot pressing to form a baseboard, the high cross-linking density and metal hybrid structure of the modified phenolic resin can enhance interlayer bonding, inhibit interlayer peeling, and improve interlayer shear strength. Under high temperature hot pressing, the zirconium cross-linking structure inhibits resin softening and reduces board deformation. The polar groups on the resin surface and the interfacial polarity of the fluorinated PET film are matched, which enhances the bonding strength through van der Waals forces. At the same time, the hardness of the hybrid network can resist friction damage and maintain the long-term effectiveness of the waterproof membrane.

[0036] (2) The hydrophilic silica of the present invention can be embedded in the phenolic resin network through physical cross-linking or "bridging action". As the modified phenolic resin penetrates into the fiber gap, the tensile strength, tear strength and folding endurance of kraft paper are significantly improved during the process of forming hydrogen bonds between the resin sulfonic acid groups and cellulose hydroxyl groups. Its high specific surface area and surface hydroxyl groups can also form hydrogen bonds or physical entanglement with the resin molecular chains, inhibiting crack propagation and enhancing the toughness of the material. The hydrophobic phenolic network and the nanoscale filling effect of silica work together to form a low surface energy coating on the paper surface, so that the contact angle changes from hydrophilic to hydrophobic, reducing water absorption.

[0037] (3) The melamine and vanillin in the synergistic powder of this invention contain a large number of polar groups such as amino and phenolic hydroxyl groups. During hot pressing, they can form hydrogen bonds or chemical bonds with other layers to build a dense cross-linked network and reduce the penetration path of water molecules. Furthermore, the aromatic ring structure and hydrophobic groups of the flame retardant DOPO may improve the hydrophobicity of the material surface through intermolecular forces, further reducing the water absorption rate and significantly enhancing the waterproof performance of the board. The flame retardant DOPO decomposes upon heating to generate phosphorus-containing free radicals, which capture active groups in the combustion chain reaction, inhibit the spread of combustion, and can also form a phosphorus-containing carbon layer to block heat and oxygen transfer and reduce the release of combustible gases. Melamine can further decompose to generate inert gases, dilute the oxygen concentration, and synergistically improve the flame retardant efficiency. The melamine resin in the synergistic powder has hydrolysis resistance, and its cross-linked structure is not easily degraded in a humid environment, which can stably maintain the mechanical properties of the material. The phenolic hydroxyl groups of vanillin react with the hydroxymethyl groups in the phenolic resin to enhance the cross-linking density between molecular chains and reduce the destructive effect of water molecules on chemical bonds. Melamine can form a three-dimensional network structure, restricting molecular chain movement and improving the material's rigidity and bending resistance. Vanillin can participate in the condensation reaction of phenolic resin through its phenolic hydroxyl groups, introducing an aromatic ring structure, enhancing molecular chain rigidity, and increasing the elastic modulus. The amino and phenolic hydroxyl groups in the synergistic powder can covalently cross-link with the hydroxymethyl groups in the phenolic resin and the active groups in the modified melamine resin, forming "molecular bridges" during hot pressing, enhancing interlayer chemical bonding, and significantly improving the interlayer bonding strength of the board.

[0038] (4) The modified melamine resin of this invention introduces a rigid benzene ring structure and a large number of hydroxyl groups through the condensation reaction of 3,4-dihydroxybenzaldehyde and melamine. The hydroxyl groups can form a tight cross-linked network through hydrogen bonds, reducing the water molecule penetration path; the hydrophobicity of the benzene ring further reduces the water absorption rate. In the subsequent process, after the resin is cured, it forms a dense network structure that fills the fiber gaps, forming a physical barrier to prevent water intrusion and significantly improves water resistance and water resistance. Melamine releases inert gas when burning, diluting oxygen and inhibiting combustion; the benzene ring structure introduced after modification has high thermal stability, which can delay thermal decomposition and significantly improve flame retardant efficiency. The benzene ring structure introduced during the modification process enhances the rigidity of the molecular chain, inhibits chain segment movement, and improves the rigidity of the material; the introduced hydroxyl groups and the multifunctional characteristics of melamine enable the formation of a three-dimensional network structure after curing, enhancing the intermolecular forces and improving mechanical strength; after the resin is impregnated into colored paper, it fills the fiber pores, forming a "resin-fiber" composite structure, which significantly improves the material's elastic modulus, resistance to elastic deformation, and static bending strength. The hydroxyl and amino groups of the modified melamine resin serve as active groups, which can be tightly bonded to paper fibers through chemical bonding and physical entanglement. The high cross-linking density further forms a strong and tough interface layer, enhancing interlayer adhesion. During hot pressing, the resin melts and penetrates into the fiber gaps. After cooling and solidification, it also forms strong bonding points, preventing interlayer peeling and significantly improving bonding strength.

[0039] Therefore, the high-strength waterproof board prepared by this invention has excellent bonding strength, waterproof and fireproof capabilities, and a wider range of application prospects. Detailed Implementation

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Unless otherwise specified, the following information pertains to some of the raw materials used in the following embodiments and comparative examples of this invention:

[0042] The hydrophilic silica was purchased from Hubei Weishi Chemical Reagent Co., Ltd., item number: HBWS-236; the phenolic resin was purchased from Pande (Shanghai) International Trading Co., Ltd., CAS: 9003-35-4.

[0043] Example 1: A method for preparing a high-strength waterproof board is as follows:

[0044] S1: Add 0.7g of montmorillonite to 10.3g of formaldehyde solution with a mass fraction of 37% and perform ultrasonic dispersion at 17℃ for 2h at a power of 30W and a frequency of 55kHz. Then add 7.5g of phenol and 1.5g of sodium hydroxide aqueous solution with a mass fraction of 2% and stir at 75℃ for 6h. Then add 50g of deionized water and 10g of anhydrous ethanol and stir at 300r / min for 30min to obtain phenolic resin emulsion.

[0045] S2: Add 6g of p-benzenesulfonic acid to 2.5g of formaldehyde solution with a mass fraction of 37% and stir for 20min. Then add it to 80g of phenolic resin emulsion and stir at 65℃ for 2h. Then centrifuge and wash the precipitate three times with deionized water and dry at 75℃ for 20h to obtain phenolic resin prepolymer.

[0046] S3: Add 5g of phenolic resin prepolymer to 100g of deionized water and stir for 1h. Then add 6g of zirconium nitrate pentahydrate and stir for 20h. Then centrifuge and wash the precipitate three times with deionized water and dry at 75℃ for 20h to obtain modified phenolic resin.

[0047] S4: Add 50g of anhydrous ethanol, 5g of modified phenolic resin, and 2g of hydrophilic silica to 50g of deionized water and perform ultrasonic treatment at 100W and 55kHz for 1 hour. Then immerse the mixture in kraft paper for 0.5 hours. After removing the paper, air dry it at 20℃ for 12 hours and then dry it at 75℃ for 6 hours to obtain modified kraft paper.

[0048] S5: Add 8g of melamine, 28g of vanillin, and 28g of flame retardant DOPO to 100g of anhydrous ethanol and stir at 70℃ for 40min. Then raise the temperature to 90℃ and add 3g of benzenesulfonic acid. React at 90℃ for 8h and then cool to 20℃. Then pour into 300mL of deionized water and stir for 10min. Finally, filter, wash, dry, and pulverize to obtain the synergistic powder.

[0049] S6: Under a nitrogen atmosphere, 100 mL of deionized water was mixed with 2.1 g of melamine and stirred at 90 °C for 20 min. Then, 6.9 g of 3,4-dihydroxybenzaldehyde was added and the pH was adjusted to 9 with a 5% sodium hydroxide aqueous solution. The mixture was reacted at 90 °C for 2 h, cooled to room temperature, and filtered. The filtrate was dehydrated by rotary evaporation under reduced pressure, washed three times with anhydrous ethanol, and dried to obtain modified melamine resin.

[0050] S7: Add 5g of synergistic powder to 100mL of deionized water and sonicate at 30W and 55kHz for 30min. Then add 5g of modified melamine resin and stir at 60℃ for 20min. Then immerse the paper in the mixture for 2h. After removing the paper, air dry it at 20℃ for 12h and then dry it at 75℃ for 4h to obtain the modified paper.

[0051] S8: Overlap three sheets of modified kraft paper, then heat-press and cure them at 1 MPa and 110℃ for 15 min, and then heat-press and cure them at 1 MPa and 155℃ for 10 min to obtain the kraft paper layer.

[0052] S9: Place one layer of kraft paper on top of one layer of modified colored paper, then place another layer of modified colored paper on top of the kraft paper, and then heat-press and cure at 1MPa and 120℃ for 1 minute to obtain the baseboard.

[0053] S10: A steel plate, two base plates, and another anti-fingerprint polymer film (a PET film with a fluorine coating on the surface, a pure water contact angle of 120°, a hexadecane contact angle of 72°, a dynamic friction coefficient of 0.03, and a hardness of 9H) are sequentially stacked on a single anti-fingerprint polymer film (a PET film with a fluorine coating on the surface, a pure water contact angle of 120°, a hexadecane contact angle of 72°, a dynamic friction coefficient of 0.03, and a hardness of 9H). The film is then hot-pressed and cured at 8MPa and 150℃ for 20 minutes. After cooling to 25℃, the film is removed to obtain a high-strength waterproof board.

[0054] Example 2: A method for preparing a high-strength waterproof board is as follows:

[0055] S1: Add 0.8g of montmorillonite to 11.6g of formaldehyde solution with a mass fraction of 37% and perform ultrasonic dispersion at 19℃ for 3h at a power of 35W and a frequency of 58kHz. Then add 8.4g of phenol and 1.7g of sodium hydroxide aqueous solution with a mass fraction of 2% and stir at 78℃ for 7h. Then add 56.3g of deionized water and 11.3g of anhydrous ethanol and stir at 350r / min for 45min to obtain phenolic resin emulsion.

[0056] S2: Add 6.5g of p-benzenesulfonic acid to 2.8g of formaldehyde solution with a mass fraction of 37% and stir for 25min. Then add it to 90g of phenolic resin emulsion and stir at 70℃ for 3h. Then centrifuge and wash the precipitate with deionized water 4 times and dry at 78℃ for 25h to obtain phenolic resin prepolymer.

[0057] S3: Add 7.5g of phenolic resin prepolymer to 150g of deionized water and stir for 1.5h. Then add 9g of zirconium nitrate pentahydrate and stir for 22h. Then centrifuge and wash the precipitate four times with deionized water and dry at 78℃ for 25h to obtain modified phenolic resin.

[0058] S4: Add 75g of anhydrous ethanol, 7.5g of modified phenolic resin, and 4g of hydrophilic silica to 75g of deionized water and perform ultrasonic treatment at 200W and 58kHz for 1.5h. Then immerse it in kraft paper for 1h. After taking it out, air dry it at 30℃ for 18h and then dry it at 78℃ for 8h to obtain modified kraft paper.

[0059] S5: Add 9g of melamine, 32g of vanillin, and 32g of flame retardant DOPO to 115g of anhydrous ethanol and stir at 73℃ for 50min. Then raise the temperature to 93℃ and add 4g of benzenesulfonic acid. React at 93℃ for 10h and then cool to 30℃. Pour into 400mL of deionized water and stir for 20min. Finally, filter, wash, dry, and pulverize to obtain the synergistic powder.

[0060] S6: Under a nitrogen atmosphere, 110 mL of deionized water was mixed with 2.3 g of melamine and stirred at 93 °C for 25 min. Then, 7.6 g of 3,4-dihydroxybenzaldehyde was added and the pH was adjusted to 9 with a 5% sodium hydroxide aqueous solution. The mixture was reacted at 93 °C for 2.5 h, cooled to room temperature, and filtered. The filtrate was evaporated under reduced pressure to remove water, washed four times with anhydrous ethanol, and dried to obtain modified melamine resin.

[0061] S7: Add 5g of synergistic powder to 130mL of deionized water and sonicate at 35W and 58kHz for 35min. Then add 7.5g of modified melamine resin and stir at 65℃ for 25min. Then immerse the paper in the mixture for 3h. After removing the paper, air dry it at 30℃ for 18h and then dry it at 78℃ for 7h to obtain the modified paper.

[0062] S8: Overlap four sheets of modified kraft paper, then heat-press and cure them at 1.5MPa and 130℃ for 20 minutes, and then heat-press and cure them at 1.5MPa and 160℃ for 15 minutes to obtain the kraft paper layer.

[0063] S9: Place one layer of kraft paper on top of one layer of modified colored paper, then place one layer of modified colored paper on top of the kraft paper, and then heat-press and cure at 1.5MPa and 125℃ for 1.5min to obtain the baseboard.

[0064] S10: A steel plate, two base plates, and another anti-fingerprint polymer film (a PET film with a fluorine coating, a pure water contact angle of 120°, a hexadecane contact angle of 72°, a dynamic friction coefficient of 0.03, and a hardness of 9H) are sequentially stacked on a single anti-fingerprint polymer film (a PET film with a fluorine coating, a pure water contact angle of 120°, a hexadecane contact angle of 72°, a dynamic friction coefficient of 0.03, and a hardness of 9H). The film is then hot-pressed and cured at 10 MPa and 160°C for 40 minutes. After cooling to 30°C, the film is removed to obtain a high-strength waterproof board.

[0065] Example 3: A method for preparing a high-strength waterproof board is as follows:

[0066] S1: Add 0.9g of montmorillonite to 12.9g of formaldehyde solution with a mass fraction of 37% and perform ultrasonic dispersion at 21℃ for 4h at a power of 40W and a frequency of 60kHz. Then add 9.4g of phenol and 1.9g of sodium hydroxide aqueous solution with a mass fraction of 2% and stir at 80℃ for 8h. Then add 62.5g of deionized water and 12.5g of anhydrous ethanol and stir at 400r / min for 60min to obtain phenolic resin emulsion.

[0067] S2: Add 7g of p-benzenesulfonic acid to 3.1g of formaldehyde solution with a mass fraction of 37% and stir for 30min. Then add it to 100g of phenolic resin emulsion and stir at 75℃ for 4h. Then centrifuge and wash the precipitate 5 times with deionized water and dry at 80℃ for 30h to obtain phenolic resin prepolymer.

[0068] S3: Add 10g of phenolic resin prepolymer to 200g of deionized water and stir for 2h. Then add 12g of zirconium nitrate pentahydrate and stir for 24h. Then centrifuge and wash the precipitate 5 times with deionized water and dry at 80℃ for 30h to obtain modified phenolic resin.

[0069] S4: Add 100g of anhydrous ethanol, 10g of modified phenolic resin, and 6g of hydrophilic silica to 100g of deionized water and perform ultrasonic treatment at 300W and 60kHz for 2 hours. Then immerse the mixture in kraft paper for 2 hours. After removing the paper, air dry it at 40℃ for 24 hours and then dry it at 80℃ for 10 hours to obtain modified kraft paper.

[0070] S5: Add 10g of melamine, 35g of vanillin, and 35g of flame retardant DOPO to 130g of anhydrous ethanol and stir at 75℃ for 60min. Then raise the temperature to 95℃ and add 5g of benzenesulfonic acid. React at 95℃ for 12h and then cool to 35℃. Pour into 500mL of deionized water and stir for 30min. Finally, filter, wash, dry, and pulverize to obtain the synergistic powder.

[0071] S6: Under a nitrogen atmosphere, 120 mL of deionized water and 2.5 g of melamine were mixed and stirred at 95 °C for 30 min. Then, 8.3 g of 3,4-dihydroxybenzaldehyde was added and the pH was adjusted to 9 with a 5% sodium hydroxide aqueous solution. The mixture was reacted at 95 °C for 3 h, cooled to room temperature, and filtered. The filtrate was removed by rotary evaporation under reduced pressure, washed 5 times with anhydrous ethanol, and dried to obtain modified melamine resin.

[0072] S7: Add 5g of synergistic powder to 150mL of deionized water and sonicate at 40W and 60kHz for 40min. Then add 10g of modified melamine resin and stir at 70℃ for 30min. Then immerse the paper in the mixture for 4h. After removing the paper, air dry it at 40℃ for 24h and then dry it at 80℃ for 10h to obtain the modified paper.

[0073] S8: Overlap 5 sheets of modified kraft paper, then heat-press and cure at 2MPa and 150℃ for 25 minutes, and then heat-press and cure at 2MPa and 165℃ for 20 minutes to obtain the kraft paper layer.

[0074] S9: Place one layer of kraft paper on top of one layer of modified colored paper, then place one layer of modified colored paper on top of the kraft paper, and then heat-press and cure at 2MPa and 130℃ for 2 minutes to obtain the base board.

[0075] S10: A steel plate, two base plates, and another anti-fingerprint polymer film (a PET film with a fluorine coating on the surface, a pure water contact angle of 120°, a hexadecane contact angle of 72°, a dynamic friction coefficient of 0.03, and a hardness of 9H) are sequentially stacked on a single anti-fingerprint polymer film (a PET film with a fluorine coating on the surface, a pure water contact angle of 120°, a hexadecane contact angle of 72°, a dynamic friction coefficient of 0.03, and a hardness of 9H). The film is then hot-pressed and cured at 12MPa and 170℃ for 60 minutes. After cooling to 40℃, the film is removed to obtain a high-strength waterproof board.

[0076] Comparative Example 1:

[0077] Compared with Example 1, this comparative example only did not add "montmorillonite" in the preparation process of S1. All other steps and parameters were the same, and will not be repeated here. The final result was a high-strength waterproof board.

[0078] Comparative Example 2:

[0079] Compared with Example 1, this comparative example only replaces the "modified phenolic resin" added in the preparation process of S4 with the "phenolic resin prepolymer" prepared in S2. All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a high-strength waterproof board is obtained.

[0080] Comparative Example 3:

[0081] Compared with Example 1, this comparative example only did not add "hydrophilic silica" in the preparation process of S4. All other steps and parameters were the same, and will not be repeated here. The final result was a high-strength waterproof board.

[0082] Comparative Example 4:

[0083] Compared with Example 1, this comparative example only replaces "adding 50g of anhydrous ethanol, 5g of modified phenolic resin, and 2g of hydrophilic silica to 50g of deionized water" in the preparation process of S4 with "adding 50g of anhydrous ethanol and 5g of phenolic resin to 50g of deionized water". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a high-strength waterproof board is obtained.

[0084] Comparative Example 5:

[0085] Compared with Example 1, this comparative example only did not add "flame retardant DOPO" in the preparation process of S5. All other steps and parameters were the same, and will not be repeated here. The final result was a high-strength waterproof board.

[0086] Comparative Example 6:

[0087] Compared with Example 1, this comparative example only replaces the "enhancing powder" added during the preparation of S7 with "modified melamine resin". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a high-strength waterproof board is obtained.

[0088] Comparative Example 7:

[0089] Compared with Example 1, this comparative example only replaces the "modified melamine resin" added in the preparation process of S7 with "enhancing powder". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a high-strength waterproof board is obtained.

[0090] Performance testing:

[0091] Flame retardancy testing:

[0092] Referring to GB / T 2408-2021 "Determination of flammability of plastics by horizontal and vertical burning methods", the flame retardant rating (grade) of the composite wood-plastic flooring prepared in Examples 1-3 and Comparative Examples 1-7 of this invention was determined by vertical burning test (V method). The test results are shown in Table 1.

[0093] Determination of water absorption rate:

[0094] Referring to GB / T 17657-2013 "Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels", the water absorption rate (%) of the high-strength waterproof boards prepared in Examples 1-3 and Comparative Examples 1-7 was determined after soaking in deionized water for 7 days. The test results are shown in Table 1.

[0095] Determination of static bending strength:

[0096] Referring to the three-point bending method in GB / T 17657-2013 "Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels", the static bending strength (MPa) of the high-strength waterproof boards prepared in Examples 1-3 and Comparative Examples 1-7 was determined. The test results are shown in Table 1.

[0097] Determination of adhesive strength:

[0098] Referring to the surface bonding strength test method in 4.1 of GB / T 17657-2013 "Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels", the bonding strength (MPa) of the high-strength waterproof boards prepared in Examples 1-3 and Comparative Examples 1-7 was determined. The test results are shown in Table 1.

[0099] Water resistance test:

[0100] Referring to the surface bonding strength determination method in 4.1 of GB / T 17657-2013 "Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels", the bonding strength retention rate (%) of the high-strength waterproof boards prepared in Examples 1-3 and Comparative Examples 1-7 after soaking in deionized water for 7 days was determined to reflect the water resistance of the high-strength waterproof boards of the present invention. The test results are shown in Table 1.

[0101] Table 1: Performance test results of Examples 1-3 and Comparative Examples 1-7

[0102] project Flame retardancy / grade Water absorption rate / % Static bending strength / MPa Bond strength / MPa Water resistance / % Example 1 V-0 1.2 132.6 7.2 98.7 Example 2 V-0 1.0 134.5 7.5 99.0 Example 3 V-0 1.3 133.3 7.3 98.9 Comparative Example 1 V-0 1.6 129.7 7.0 97.2 Comparative Example 2 V-0 2.6 106.8 5.6 88.9 Comparative Example 3 V-0 2.0 122.5 6.9 97.8 Comparative Example 4 V-1 3.3 98.9 4.9 85.6 Comparative Example 5 V-0 2.4 131.2 7.1 97.5 Comparative Example 6 V-1 1.5 138.5 6.8 98.2 Comparative Example 7 V-0 1.4 109.2 6.5 91.5

[0103] Data Analysis:

[0104] As can be seen from Table 1, the high-strength waterproof board prepared in the embodiments of the present invention has excellent bonding strength, waterproofness and fire resistance.

[0105] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for preparing a high-strength waterproof board, characterized in that, Includes the following steps: One steel plate, two base plates, and one anti-fingerprint polymer film are stacked on top of one anti-fingerprint polymer film, then hot-pressed and cured, and after cooling, the board is removed to obtain a high-strength waterproof board. The baseboard is prepared from modified kraft paper and modified colored paper; The modified kraft paper is prepared as follows: B1: Add montmorillonite to formaldehyde aqueous solution and ultrasonically disperse for 2-4 hours. Then add phenol and sodium hydroxide aqueous solution and stir at 75-80℃ for 6-8 hours. Then add deionized water and anhydrous ethanol and stir for 30-60 minutes to obtain phenolic resin emulsion. B2: Add p-benzenesulfonic acid to formaldehyde aqueous solution and stir for 20-30 min. Then add it to phenolic resin emulsion and stir at 65-75℃ for 2-4 h. Then centrifuge, wash the precipitate and dry to obtain phenolic resin prepolymer. B3: Add phenolic resin prepolymer to deionized water and stir for 1-2 hours, then add zirconium nitrate pentahydrate and stir for 20-24 hours, then centrifuge, wash and precipitate, and dry to obtain modified phenolic resin. B4: Add anhydrous ethanol, modified phenolic resin, and hydrophilic silica to deionized water and sonicate for 1-2 hours. Then immerse the mixture in kraft paper for 0.5-2 hours, remove and dry to obtain modified kraft paper. The modified colored paper is prepared as follows: C1: Melamine, vanillin, and flame retardant DOPO are added to anhydrous ethanol and stirred at 70-75℃ for 40-60 min. Then, the temperature is raised to 90-95℃ and benzenesulfonic acid is added and reacted for 8-12 h. After cooling, it is poured into deionized water and stirred for 10-30 min. Finally, after filtration, washing, drying, and pulverization, the synergistic powder is obtained. C2: Under a nitrogen atmosphere, deionized water and melamine are mixed and stirred at 90-95℃ for 20-30 min. Then, 3,4-dihydroxybenzaldehyde is added and the pH is adjusted to 9. The mixture is reacted at 90-95℃ for 2-3 h, cooled to room temperature and filtered. The filtrate is evaporated under reduced pressure to remove water, and the precipitate is washed with anhydrous ethanol and dried to obtain modified melamine resin. C3: Add synergistic powder to deionized water and sonicate for 30-40 minutes. Then add modified melamine resin and stir at 60-70℃ for 20-30 minutes. Then immerse the colored paper in the mixture for 2-4 hours, remove it and dry it to obtain modified colored paper.

2. The method for preparing the high-strength waterproof board according to claim 1, characterized in that, The preparation method of the base plate is as follows: A1: Overlap 3-5 sheets of modified kraft paper, heat-press and cure to obtain a kraft paper layer; A2: Place one layer of kraft paper on top of one layer of modified colored paper, then place another layer of modified colored paper on top of the kraft paper, and heat-press to cure to obtain the baseboard.

3. The method for preparing the high-strength waterproof board according to claim 1, characterized in that, The pressure during hot pressing curing is 8-12 MPa, the temperature is 150-170℃, and the duration is 20-60 min.

4. The method for preparing the high-strength waterproof board according to claim 1, characterized in that, The mass ratio of formaldehyde aqueous solution, montmorillonite, phenol, sodium hydroxide aqueous solution, deionized water, and anhydrous ethanol in B1 is 10.3-12.9:0.7-0.9:7.5-9.4:1.5-1.9:50-62.5:10-12.5; The formaldehyde aqueous solution described in B1 has a mass fraction of 37%; The sodium hydroxide aqueous solution described in B1 has a mass fraction of 2%; The mass ratio of formaldehyde aqueous solution, p-benzenesulfonic acid, and phenolic resin emulsion in B2 is 2.5-3.1:6-7:80-100; The formaldehyde aqueous solution described in B2 has a mass fraction of 37%.

5. The method for preparing the high-strength waterproof board according to claim 1, characterized in that, The mass ratio of deionized water, phenolic resin prepolymer, and zirconium nitrate pentahydrate described in B3 is 100-200:5-10:6-12; The mass ratio of deionized water, anhydrous ethanol, modified phenolic resin, and hydrophilic silica mentioned in B4 is 50-100:50-100:5-10:2-6.

6. The method for preparing the high-strength waterproof board according to claim 1, characterized in that, The mass ratio of anhydrous ethanol, melamine, vanillin, flame retardant DOPO, benzenesulfonic acid, and deionized water in C1 is 100-130:8-10:28-35:28-35:3-5:300-500; The mass ratio of deionized water, melamine, and 3,4-dihydroxybenzaldehyde in C2 is 100-120: 2.1-2.5: 6.9-8.

3.

7. The method for preparing the high-strength waterproof board according to claim 1, characterized in that, The mass ratio of deionized water, synergistic powder, and modified melamine resin in C3 is 100-150:5:5-10.

8. A high-strength waterproof board, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.