Inorganic fireproof plate as well as preparation method and application thereof

Abstract

The invention discloses an inorganic fireproof plate and a preparation method and application thereof, the inorganic fireproof plate comprises a core layer and a facing layer, the core layer is composed of inorganic fibers, phenolic resin and a silane coupling agent; and the facing layer is phenolic resin facing paper containing nano titanium dioxide. The preparation process comprises the steps of fiber fusion centrifugation, cyclone flow mixing, hot-pressing curing and the like. The prepared inorganic fireproof board has the advantages of fire resistance, water resistance, high strength, low VOC and the like, solves the problems that a traditional adhesive is poor in water resistance, insufficient in fire resistance and excessive in VOC, and is suitable for various scenes such as building external wall heat preservation, indoor decoration suspended ceilings, industrial equipment heat insulation and humid environment partition walls.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to an inorganic fireproof board, its preparation method, and its application. Background Technology

[0002] Existing inorganic boards on the market, such as calcium silicate boards, gypsum boards, and magnesium oxide boards, are generally brittle, prone to moisture absorption, and have low strength, making them susceptible to detachment. Other boards, such as plywood and MDF, also easily absorb moisture, causing detachment problems. Furthermore, they are prone to mold growth after absorbing moisture, posing a health hazard to the home, and their flame-retardant properties do not meet requirements.

[0003] High-pressure fireproof boards typically use kraft paper as the base material, impregnated with resin, resulting in high strength and the ability to be manufactured into larger sizes. However, they also have the following drawbacks:

[0004] (1) Insufficient fire resistance: The base material is paper-based, which has low fire resistance and cannot meet the Class A fire resistance standard.

[0005] (2) VOC release problem: The large amount of glue applied during the curing process releases harmful gases such as formaldehyde, and the formaldehyde exceedance rate in indoor decoration is as high as 76%.

[0006] Therefore, developing new inorganic boards that combine fire resistance, water resistance, low VOC, and high strength has become a pressing technical challenge for the industry. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, the present invention aims to provide an inorganic fireproof board and its preparation method. This inorganic fireproof board has the advantages of fire resistance, water resistance, high strength and low VOC, and solves the problems of poor water resistance, insufficient fire resistance and excessive VOC of traditional inorganic boards. It is suitable for various scenarios such as building exterior wall insulation, interior decorative ceiling, industrial equipment heat insulation, and partition walls in humid environments.

[0008] This invention is achieved through the following technical solution:

[0009] This invention provides an inorganic fireproof board, comprising a core layer and a decorative layer. The core layer is composed of inorganic fibers, phenolic resin, and a silane coupling agent. The decorative layer is a phenolic resin laminate containing nano-titanium dioxide.

[0010] Preferably, the inorganic fiber is selected from at least one of basalt short fiber or aluminosilicate fiber.

[0011] The substrate of this invention uses inorganic fibers such as basalt short fibers and aluminum silicate fibers, which endow the substrate with good flame retardant and fireproof properties.

[0012] More preferably, the inorganic fiber has a length of 2-3 mm and a diameter of 5-10 μm.

[0013] The basalt short fibers described in this invention are formed by melting basalt at 1500℃ and then forming fibers with a diameter of 5-10μm under centrifugal force of 20000-25000rpm, which are then cut into short fibers with a length of 2-3mm.

[0014] Preferably, the phenolic resin is phenolic resin powder or phenolic resin liquid.

[0015] The phenolic resin powder of this invention has an average particle size of 50-100 μm; the phenolic resin powder can be obtained commercially available or prepared by the following method:

[0016] Add 35-40 parts by weight of 37% formaldehyde aqueous solution, 1-2 parts by weight of water, and adjust the pH to 5.5-6.5 with hydrochloric acid; add 35-50 parts by weight of phenol, and heat evenly to 85-90℃, and maintain the temperature for 120-150 minutes; add 5-10 parts by weight of melamine, and add hydrochloric acid solution within the addition ratio range, maintaining the temperature at 90℃; dehydrate under normal pressure; grind into powder, add curing agent (such as hexamethylenetetramine), and discharge to obtain phenolic resin powder.

[0017] The solid content of the phenolic resin liquid of this invention is 40-60%, and the viscosity at 25°C is 300-1200 mPa·s. The phenolic resin liquid of this invention can be obtained commercially available or prepared by the following method:

[0018] Add 45-55 parts by weight of 37% formaldehyde aqueous solution, 1-2 parts by weight of water, and triethylamine solution to adjust the pH to between 7.5 and 10.5; add 20-25 parts by weight of phenol, and uniformly heat to 65°C, maintaining the temperature for 10-30 minutes; add 5-10 parts by weight of melamine, and add triethylamine solution within the addition ratio range, raising the temperature to 80°C; maintain the temperature and test the water solubility; when the cloud point appears, add 15-20 parts by weight of urea, the remaining water, formaldehyde solution, and triethylamine solution; heat to 85°C and maintain the temperature; when the viscosity of the compound is tested to be 50 cps, cool down, continue cooling to below 35°C, and discharge the material to obtain the phenolic resin solution.

[0019] Traditional adhesives suffer from poor water resistance, insufficient fire resistance, and excessive VOC emissions. Existing technologies, such as high-pressure fireproof boards, use resins that require large application amounts and release harmful gases like formaldehyde during curing (leading to high rates of formaldehyde exceeding standards in indoor decoration). In contrast, the phenolic resin powder or liquid of this invention has a free phenol content of <0.5%, reducing initial VOC release by 60%, thus solving the aforementioned problems of traditional materials. Combined with the nano-titanium dioxide in the finishing layer (achieving a 92% formaldehyde removal rate in 24 hours), it further reduces VOC impact, resulting in an inorganic fireproof board that combines fire resistance, water resistance, high strength, and low VOCs.

[0020] This invention adds 1-3% nano-titanium dioxide filler to the phenolic resin veneer paper of the decorative layer, forming a filler coating of 3-7 nm. The nano-titanium dioxide generates ·OH free radicals under light irradiation, achieving a formaldehyde removal rate of 92% within 24 hours. By controlling the filler coating within the 3-7 nm range, this invention ensures both the uniform distribution and photocatalytic activity of the nano-titanium dioxide, while avoiding the reduced resin matrix adhesion due to an excessively thick coating or insufficient formaldehyde removal due to an excessively thin coating. This design is suitable for the composite process of the decorative layer and core layer, as well as the overall performance requirements of the board.

[0021] The silane coupling agent described in this invention is selected from at least one of γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, or N-phenyl-3-aminopropyltrimethoxysilane.

[0022] The amount of the silane coupling agent used in this invention is 0.05-1% of the phenolic resin.

[0023] This invention uses a silane coupling agent, which, through condensation and cross-linking reactions with inorganic fibers, can improve the interfacial bonding force between inorganic fibers and phenolic resin, thereby further enhancing the strength of the inorganic fireproof board.

[0024] The inorganic fireproof board described above can be prepared by either a dry process or a wet process.

[0025] This invention provides a dry process for inorganic fireproof boards, comprising the following steps:

[0026] S1. Mixing: First, the inorganic fibers are spray-mixed with the silane coupling agent, and then mixed with the phenolic resin powder in a cyclone to obtain a mixture;

[0027] S2. Hot pressing and curing: The mixture is hot-pressed and cured for 240-360 seconds to obtain the core layer;

[0028] S3. Finishing layer composite: Phenolic resin veneer containing nano-titanium dioxide is laid flat on the surface of the core layer and cured for 240-360 seconds at 0.8-1.2MPa and 120-140℃ to form the finishing layer, thus obtaining the inorganic fireproof board.

[0029] Preferably, in step S1, the cyclone mixing speed is 2000-3000 rpm, the time is 6-10 minutes, and the wind speed is controlled at 15-20 m / s.

[0030] Preferably, in step S1, the mass ratio of the inorganic fiber to the phenolic resin powder is 8-10:1.

[0031] Preferably, in step S2, the hot-press curing process employs a three-stage heating procedure:

[0032] Stage 1: Place the mixture in a temperature-controlled press and heat it from room temperature to 110-130℃ at a rate of 4-6℃ / min, while maintaining a pressure of 0.4-0.6MPa for 25-35 seconds.

[0033] Phase 2: Continue heating to 170-190℃, simultaneously pressurizing to 2.0-2.5MPa, and hold for 180-300 seconds;

[0034] Phase 3: Reduce the temperature from 170-190℃ to room temperature, with the depressurization rate controlled at 4-5 MPa / min, lasting approximately 25-35 seconds.

[0035] The hot-press curing of the present invention, through a staged programmed temperature increase curing process, has the following advantages:

[0036] Ensuring thorough and uniform curing: Staged heating allows the phenolic resin powder to gradually complete the cross-linking reaction in different temperature ranges, avoiding the problem of incomplete internal curing due to local over-curing caused by instantaneous high temperature, and ensuring the uniformity of the overall core structure.

[0037] Reduce internal stress and defects: Stage 1, low temperature and low pressure, provides initial shaping buffer for the material; Stage 2, medium temperature and high pressure, promotes full resin flow and fills the fiber gaps; Stage 3, slow pressure and temperature reduction, can release the internal stress generated during the curing process and reduce defects such as core layer cracking and warping.

[0038] Adapting to fiber and resin properties: Avoiding direct impact from high temperatures that could damage the properties of inorganic fibers (such as basalt fibers), while matching the curing reaction kinetics of phenolic resin powder to ensure bonding strength while maintaining the supporting role of the fiber skeleton for the core layer strength.

[0039] Improved process stability and efficiency: Clear temperature, pressure and time parameters make the curing process controllable, reduce human error, and the total curing time of 240 to 360 seconds takes into account production efficiency and is suitable for large-scale production.

[0040] This invention also provides a wet process for inorganic fireproof boards, comprising the following steps:

[0041] (1) Mixing: Inorganic fibers are mixed with phenolic resin liquid containing silane coupling agent to form a uniform slurry;

[0042] (2) Pre-drying: The slurry is pre-dried in hot air circulation at 60-80℃ until the moisture content is <10%;

[0043] (3) Hot pressing curing molding: The pre-dried slurry is placed in a temperature-controlled press and heated from room temperature to 70-90℃ at a rate of 4-6℃ / min, while maintaining a pressure of 0.4-0.6MPa for about 25-35 seconds; the temperature is further increased to 170-190℃ and the pressure is increased to 2.0-2.5MPa, and the temperature is maintained for 180-300 seconds; the temperature is then reduced from 170-190℃ to room temperature at a rate of 4-5MPa / min for about 25-35 seconds to obtain the core layer;

[0044] (4) Surface layer composite: Phenolic resin veneer containing nano-titanium dioxide is laid flat on the surface of the core layer and cured for 240-360 seconds at 0.8-1.2MPa and 120-140℃ to form a surface layer, thus obtaining inorganic fireproof board.

[0045] Preferably, in step (1), the inorganic fiber and phenolic resin liquid are mixed in a ratio of 4:1 to 5:1, the stirring speed is 600-1000 rpm, and the time is 15-35 minutes.

[0046] This invention involves mixing inorganic fibers and phenolic resin solution in a wet process at a ratio of 4:1 to 5:1. Sufficient phenolic resin solution ensures thorough wetting of the inorganic fibers, preventing agglomeration and guaranteeing uniform slurry flow. Excessive phenolic resin solution results in an overly thin slurry, causing the inorganic fibers to easily separate. Within this ratio, the phenolic resin and inorganic fibers are tightly bonded, forming a stable network after curing and ensuring flexural strength. An imbalanced ratio leads to loose bonding or weakened fiber support. Furthermore, this ratio coordinates moisture evaporation and resin shrinkage during drying, preventing crusting, voids, or exposed fibers, ensuring a water absorption rate of ≤5%.

[0047] This invention also provides applications of the aforementioned inorganic fireproof boards in the construction and transportation sectors. Combining the multi-field application characteristics of inorganic fiber density boards, the inorganic fireproof boards of this invention can be further expanded to a wider range of scenarios. In the construction field, in addition to conventional interior decoration and wall insulation, its Class A non-combustible performance and low VOC characteristics make it particularly suitable for ceilings, partitions, and evacuation routes in densely populated places such as large commercial complexes, hospitals, and schools, effectively delaying the spread of fire and reducing the release of toxic gases. In industrial settings, thanks to its high-temperature resistance (suitable for long-term use temperatures above 600℃) and anti-aging advantages, it can be used as heat insulation linings and fireproof walls for petrochemical workshops and high-temperature kilns, replacing traditional metal or ceramic materials to reduce weight and cost.

[0048] In the transportation sector, the high strength and fire resistance of this material meet the flame-retardant requirements of high-speed rail carriage interiors and ship bulkheads, complying with International Maritime Organization (IMO) and rail transit fire protection standards. In special environments, such as nuclear power plant control rooms and data centers where safety requirements are stringent, its stable physical properties and radiation resistance (compatible with mineral fiber substrates) provide long-term reliable protection. Furthermore, combined with its waterproof and weather-resistant properties, it solves the problems of moisture absorption, mold growth, and strength degradation associated with traditional materials in applications such as building exterior walls in humid regions and underground firewalls, demonstrating its comprehensive application value as a "multi-functional" material and providing innovative material solutions for green building and safety engineering.

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

[0050] The inorganic fireproof board provided by this invention has a core layer made of inorganic fiber and phenolic resin composite, and a finishing layer containing nano-titanium dioxide photocatalytic filler. Through process optimization, the prepared inorganic fireproof board has the advantages of fire resistance, water resistance, high strength and low VOC, which solves the problems of poor water resistance, insufficient fire resistance and excessive VOC of traditional inorganic boards. It is suitable for various scenarios such as building exterior wall insulation, interior decorative ceiling, industrial equipment heat insulation, and partition walls in humid environments. Detailed Implementation

[0051] The present invention will be further illustrated below through specific embodiments. The following embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments.

[0052] Example 1: This example provides a dry method for preparing inorganic fireproof boards, the specific steps of which are as follows:

[0053] (1) Synthesis of phenolic resin powder:

[0054] a. Add 55 parts by weight of phenol and 5.5 parts by weight of water, and stir until the phenol is completely dissolved; add oxalic acid (0.8 parts by weight of total amount) to adjust the pH to 6.0;

[0055] b. Add 38 parts by weight of 37% formaldehyde aqueous solution at a rate of 1-2 parts / minute. After the addition is complete, heat the solution evenly to 90°C and maintain the temperature for 135 minutes.

[0056] c. Add 8 parts by weight of melamine, and add the remaining oxalic acid (total amount ≤ 0.8 parts) to maintain pH 5.8-6.2, keep the temperature at 90℃, and continue the reaction for 60 minutes;

[0057] d. Dehydrate under normal pressure until the solid content of the system is ≥85%;

[0058] e. Heat to 120℃ and hold for 30 minutes, then continue dehydration under normal pressure until the solid content is 90-95%; purge with nitrogen (flow rate 0.5-1L / min) for 40-60 minutes until the free phenol content is <0.5%, then remove from the reactor;

[0059] f. Grind the powder, pass it through a 180-mesh sieve, add hexamethylenetetramine, and discharge the powder to obtain phenolic resin powder;

[0060] (2) Core layer preparation

[0061] Fiber preparation: After basalt is melted at 1500℃, it is formed into 8μm diameter fibers under centrifugal force of 22000rpm, and then cut into short fibers with a length of 2.5mm.

[0062] Mixing process: First, the inorganic fiber and silane coupling agent are sprayed and mixed, and then mixed with phenolic resin powder at a ratio of 9:1. The mixture is then mixed in a cyclone mixer at 2000 rpm for 8 minutes with the wind speed controlled at 18 m / s.

[0063] Hot pressing curing molding: Utilizing a three-stage heating process:

[0064] Stage 1: Place the mixture in a temperature-controlled press and heat it from room temperature to 120°C at a rate of 5°C / min, while maintaining a pressure of 0.5MPa for about 30 seconds.

[0065] Phase 2: Continue heating to 190℃ and simultaneously pressurize to 2.3MPa, holding at this temperature and pressure for 240 seconds;

[0066] Phase 3: Depressurization from 190°C to room temperature, with a depressurization rate controlled at 4.6 MPa / min, lasting approximately 30 seconds;

[0067] (3) Finishing layer composite

[0068] A phenolic resin veneer containing nano-titanium dioxide is laid flat on the surface of the core layer and cured for 300 seconds at 1MPa and 130℃ to form a decorative layer, thus obtaining an inorganic fireproof board.

[0069] Example 2: This example provides a method for wet preparation of inorganic fireproof boards, the specific steps of which are as follows:

[0070] (1) Synthesis of phenolic resin solution:

[0071] a. Add 50 parts by weight of 37% formaldehyde aqueous solution and 2 parts by weight of water to the reaction vessel, stir well, and then add triethylamine solution (initial amount 0.5 parts) to adjust the pH of the system to 9.0;

[0072] b. Add 23 parts by weight of phenol, stir until completely dissolved, then heat evenly to 65°C and keep the temperature for 20 minutes (to ensure that phenol and formaldehyde undergo initial condensation).

[0073] c. Add 8 parts by weight of melamine, and add triethylamine (0.3 parts remaining) to maintain the pH of the system at 8.5-9.5. Slowly raise the temperature to 80°C and keep the reaction at this temperature for 30 minutes.

[0074] d. Continue stirring and test the water solubility of the system. When the cloud point appears (the reaction reaches the critical degree of cross-linking), add 18 parts by weight of urea and the remaining 3.5 parts by weight of water, and stir until the urea is completely dissolved.

[0075] e. Heat to 85℃ and maintain the temperature, taking samples every 10 minutes during the process, and testing the viscosity at 25℃; when the viscosity reaches 50cps, test the solid content. If it deviates from 50%, adjust it to 50% by adding a small amount of deionized water (≤1 part); then stop heating, cool down to below 35℃, and discharge the material to obtain a phenolic resin liquid with 50% solid content.

[0076] (2) Mixing

[0077] Aluminosilicate fibers (2.5 mm in length and 8 μm in diameter) were mixed with phenolic resin liquid containing silane coupling agent at a ratio of 4.5:1 and stirred at 800 rpm for 25 minutes to form a uniform slurry.

[0078] (3) Drying and curing

[0079] Pre-drying: The mixed slurry is pre-dried in hot air at 70℃ until the moisture content is <10%;

[0080] Hot pressing curing molding: The pre-dried material is placed in a temperature-controlled press, and the temperature is increased from room temperature to 80°C at a rate of 5°C / min while maintaining a pressure of 0.5MPa for about 30 seconds; the temperature is then increased to 190°C and the pressure is increased to 2.3MPa simultaneously, and the temperature is maintained for 240 seconds; the temperature is then reduced from 190°C to room temperature at a rate of 4.5MPa / min for about 30 seconds to obtain the core layer;

[0081] (4) Finishing layer composite

[0082] A phenolic resin veneer containing nano-titanium dioxide is laid flat on the surface of the core layer and cured for 300 seconds at 1MPa and 130℃ to form a decorative layer, thus obtaining an inorganic fireproof board.

[0083] Example 3:

[0084] (1) The preparation of phenolic resin solution is the same as in Example 2;

[0085] (2) Mixing: Inorganic fibers (aluminosilicate fibers and basalt short fibers) and phenolic resin liquid with added silane coupling agent are mixed at a mass ratio of 4:1 and stirred at a speed of 1000 rpm for 15 minutes to form a uniform slurry.

[0086] (3) Drying and curing:

[0087] Pre-drying: The mixed slurry is pre-dried in hot air at 75℃ until the moisture content of the slurry is <10%;

[0088] Hot pressing curing molding: The pre-dried material is placed in a mold and then placed in a hot press. The temperature is increased from room temperature to 85°C at a rate of 5°C / min, while maintaining a pressure of 0.5MPa for about 30 seconds. The temperature is then increased to 180°C and the pressure is increased to 2.5MPa simultaneously, and the temperature is maintained for 300 seconds. The temperature is then reduced from 180°C to room temperature at a rate of 4.0MPa / min for about 30 seconds to obtain the core layer.

[0089] (4) Finishing layer composite: Phenolic resin veneer containing nano-titanium dioxide is laid flat on the surface of the core layer blank and cured for 300 seconds under 1MPa pressure and 130℃ to form a finishing layer, thus obtaining inorganic fireproof board.

[0090] Comparative Example 1:

[0091] The difference between this comparative example and Example 2 is that a two-component polyurethane adhesive (main agent to curing agent weight ratio 5:1, 50% solid content) is used instead of phenolic resin liquid, and the rest is the same as in Example 2.

[0092] During the mixing process, the two-component polyurethane adhesive is poorly compatible with inorganic fibers, leading to flocculent agglomeration of the mixed slurry. During hot-press curing, the polyurethane adhesive easily decomposes at high temperatures, releasing irritating gases, and its excessive toughness after curing is mismatched with the rigidity of the inorganic fibers. During the lamination of the decorative layer, localized peeling of the decorative layer occurs due to the poor compatibility between the polyurethane adhesive and the phenolic resin veneer paper.

[0093] Comparative Example 2:

[0094] The difference between this comparative example and Example 2 is that the hot-press curing molding did not use a segmented heating process. Instead, the pre-dried material was directly placed into the mold and placed in the hot press, where it was cured for 300 seconds at 190°C and 2.5MPa pressure in one go. The rest is the same as in Example 2.

[0095] Table 1 Performance Testing Standards

[0096] Combustion performance GB8624-2012 Water absorption rate GB / T5486-2008 Bending strength T / CNFPIA3007-2019 Formaldehyde release GB18580-2017 E0 Class Weather resistance (500h) GB / T1865-2009

[0097] Table 2 Performance test results of Examples 1-3 and Comparative Examples 1-2

[0098]

[0099]

[0100] As can be seen from the results in Table 2, the inorganic fireproof boards of Examples 1-3 of the present invention have excellent key performance characteristics, fully meet and exceed the standards, while Comparative Examples 1-2 have obvious shortcomings due to differences in process or raw materials.

[0101] In terms of combustion performance, Examples 1-3 all achieved Class A non-combustible properties, with a stable overall structure and no edge charring. This is attributed to the flame retardancy of the inorganic fibers and the stable structure formed by the staged curing of the phenolic resin. Comparative Examples 1 (polyurethane adhesive) and 2 (uncured) also achieved Class A non-combustible properties, but their edges were charred and their structural stability at high temperatures was insufficient, which is directly related to the easy decomposition of polyurethane at high temperatures and uneven curing.

[0102] In terms of flexural strength, Examples 1-3 showed strengths of 92.3 MPa, 90.5 MPa, and 93.1 MPa, respectively, far exceeding the 65 MPa of Comparative Example 1 and the 70 MPa of Comparative Example 2. This is due to the enhanced interfacial bonding force of the silane coupling agent and the reduced internal stress caused by staged curing, while the comparative examples experienced a sharp drop in strength due to poor compatibility or incomplete curing.

[0103] Regarding water absorption, Examples 1-3 had absorption rates of 4.2%, 4.5%, and 4.3%, respectively, which met the standard of ≤5%, indicating that the dense structure of the phenolic resin effectively waterproofed the water. Comparative Examples 1 (8.2%) and 2 (7.5%) exceeded the standard due to their loose structure or high porosity.

[0104] Regarding formaldehyde emission, Examples 1-3 showed an emission level of 0.028 mg / m³. 3 0.029 mg / m 3 0.027 mg / m 3 The low VOC requirement is met thanks to the low free phenolic resin and nano-titanium dioxide; Comparative Example 1 (0.06 mg / m³) 3 ) and 2 (0.05 mg / m 3 The adhesive's volatility or incomplete curing exceeded the standard.

[0105] Regarding density, Examples 1-3 have a density of 1.33-1.36 g / cm³. 3 It meets the requirement of >1.30g / cm³ 3 The standard reflects a dense structure; Comparative Example 1 (1.25 g / cm³) 3 ) and 2 (1.28 g / cm 3 The structure is loose and does not meet the standards.

[0106] In the weather resistance test, Examples 1-3 showed no obvious powdering cracks, while Comparative Example 1 showed fine cracks and Comparative Example 2 showed more obvious cracks, which confirmed the advantages of staged curing to release internal stress and the process defects of the comparative examples.

[0107] In summary, by optimizing raw materials and processes, this invention has successfully produced a board material that combines fire resistance, water resistance, high strength, low VOC, and excellent weather resistance.

Claims

1. An inorganic fireproof board, characterized in that, It includes a core layer and a finishing layer, wherein the core layer is composed of inorganic fibers and phenolic resin. It is composed of a silane coupling agent; the decorative layer is a phenolic resin laminate containing nano-titanium dioxide.

2. The inorganic fireproof board according to claim 1, characterized in that, The inorganic fiber is selected from at least one of basalt short fiber or aluminosilicate fiber; the inorganic fiber has a length of 2-3 mm and a diameter of 5-10 μm.

3. The inorganic fireproof board according to claim 2, characterized in that, The phenolic resin is phenolic resin powder or phenolic resin liquid. The solid content of the phenolic resin liquid is 40-60%, and the viscosity at 25°C is 300-1200 mPa·s. The average particle size of the phenolic resin powder is 50-100 μm.

4. The method for preparing the inorganic fireproof board according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Mixing: First, the inorganic fibers are spray-mixed with the silane coupling agent, and then mixed with the phenolic resin powder in a cyclone to obtain a mixture; S2. Hot pressing and curing: The mixture is hot-pressed and cured for 240-360 seconds to obtain the core layer; S3. Finishing layer composite: Phenolic resin veneer containing nano-titanium dioxide is laid flat on the surface of the core layer and cured for 240-360 seconds at 0.8-1.2MPa and 120-140℃ to form the finishing layer, thus obtaining the inorganic fireproof board.

5. The method for preparing the inorganic fireproof board according to claim 4, characterized in that, In step S1, the cyclone mixing speed is 2000-3000 rpm, the time is 6-10 minutes, and the wind speed is controlled at 15-20 m / s.

6. The method for preparing the inorganic fireproof board according to claim 4, characterized in that, In step S1, the mass ratio of the inorganic fiber to the phenolic resin powder is 8-10:

1.

7. The method for preparing the inorganic fireproof board according to claim 4, characterized in that, In step S2, the hot-press curing process employs a three-stage heating procedure: Stage 1: Place the mixture in a temperature-controlled press and heat it from room temperature to 110-130℃ at a rate of 4-6℃ / min, while maintaining a pressure of 0.4-0.6MPa for 25-35 seconds. Phase 2: Continue heating to 170-190℃, simultaneously pressurizing to 2.0-2.5MPa, and hold for 180-300 seconds; Phase 3: Reduce the temperature from 170-190℃ to room temperature, with the depressurization rate controlled at 4-5 MPa / min, lasting approximately 25-35 seconds.

8. The method for preparing the inorganic fireproof board according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Mixing: Inorganic fibers are mixed with phenolic resin liquid containing silane coupling agent to form a uniform slurry; (2) Pre-drying: The slurry is pre-dried in hot air circulation at 60-80℃ until the moisture content is < 10%; (3) Hot pressing and curing: Place the dried slurry in a temperature-controlled press, raise the temperature from room temperature to 70-90℃ at a rate of 4-6℃ / min, while maintaining a pressure of 0.4-0.6MPa for 25-35 seconds; continue to raise the temperature to 170-190℃ and simultaneously raise the pressure to 2.0-2.5MPa, and hold for 180-300 seconds; lower the temperature from 170-190℃ to room temperature, controlling the depressurization rate at 4-5MPa / min for about 25-35 seconds to obtain the core layer; (4) Finishing layer composite: Phenolic resin veneer containing nano-titanium dioxide is laid flat on the surface of the core layer and cured for 240-360 seconds at 0.8-1.2MPa and 120-140℃ to form a finishing layer, thus obtaining inorganic fireproof board.

9. The method for preparing the inorganic fireproof board according to claim 8, characterized in that, In step (1), the inorganic fiber and phenolic resin liquid are mixed in a ratio of 4:1 to 5:1, and the stirring speed is 600-1000 rpm for 15-35 minutes.

10. The application of the inorganic fireproof board according to any one of claims 1-3 in the fields of construction and transportation.

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