Fireproof, waterproof and antibacterial coating for tunnel and preparation method of fireproof, waterproof and antibacterial coating

Abstract

The invention provides a composition of a tunnel fireproof, waterproof and antibacterial coating and a preparation method thereof, a tunnel fireproof, waterproof and antibacterial coating composite coating is composed of a bottom sealing coating-tunnel fireproof and mildew-proof bottom sealing coating, a middle coating-tunnel fireproof and mildew-proof coating and a surface coating-fireproof, waterproof and mildew-proof nano ceramic coating. Formula compositions and preparation methods of a tunnel fireproof and mildew-proof bottom sealing coating, a tunnel fireproof and mildew-proof coating and a fireproof, waterproof and mildew-proof nano ceramic coating are respectively described in details, the thickness of the composite coating is 12-12.5 mm, and the fire endurance of the composite coating is more than 2.5 h, wherein the composite coating is formed by compounding a bottom, a middle and a surface. The composite coating has relatively high bonding strength, compressive strength, flexibility, crack resistance and freezing resistance, and has the characteristics of excellent fire resistance, waterproof and impermeable properties, mildew-proof and antibacterial properties, antifouling and self-cleaning properties, negative ion release, environment friendliness and the like.

Description

A fireproof, waterproof, and antibacterial coating for tunnels and its preparation method Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a fireproof, waterproof and antibacterial coating for tunnels and its preparation method. Background Technology

[0002] With the development of my country's highway, railway, and subway transportation networks, tunnels and underground projects are becoming increasingly common. Tunnels are not only transportation channels but also, in some cases, channels for fiber optic cables, power transmission cables, and oil and water transport. In the event of a fire within a tunnel or underground project, the reinforced concrete structure is highly susceptible to cracking and collapse due to thermal expansion. Fires in tunnels and underground projects result in the greatest economic losses, the most difficult repairs, and the longest periods of downtime. Therefore, the structural fire protection of tunnels and underground projects has attracted significant attention from safety departments, and the state has issued mandatory tunnel fire safety regulations, requiring fire protection for railway, highway, and subway tunnels to improve their fire safety. To prevent damage to the reinforced concrete structures in tunnels and underground projects during a fire and minimize economic losses, applying fire-retardant coatings to the concrete is an economical and effective method.

[0003] Due to the harsh environment of tunnels and underground engineering projects, such as high humidity, poor ventilation, strong vibration from vehicles, strong wind pressure, large damage caused by freeze-thaw cycles, and difficulty in dispersing smoke and dust, higher requirements are placed on fire-retardant coatings: (1) The coating should solidify and dry quickly in humid environments and have high bonding strength and compressive strength, while also having a certain degree of flexibility; (2) The coating must have excellent water resistance and waterproof properties. The fire resistance of tunnel fire-retardant coatings must be based on the high crack resistance and excellent water resistance and waterproof properties of the coating; (3) Fire-retardant coatings used in tunnels and underground engineering projects in cold regions should also have antifreeze properties; (4) The fire resistance limit of the coating should be increased while the coating thickness should be reduced (currently the thickness is 20mm and the fire resistance limit is 120min); (5) The coating should not produce harmful smoke when exposed to fire, and the coating should be green and environmentally friendly; (6) The construction should be simple and the price should be low.

[0004] Currently, most of the fireproof coatings used in tunnels and underground engineering in China are inorganic thermal insulation mortar-type thick-coat fireproof coatings. Although their coatings have good fire resistance and heat insulation performance, they also have some insurmountable disadvantages: (1) Poor waterproof performance. Due to the rough and porous structure of the coating and the well-developed capillary structure, the waterproof and seepage prevention performance is poor. After the coating absorbs moisture, the thermal resistance value decreases and the fire resistance and heat insulation performance decreases. (2) The internal environment of tunnels and underground engineering is humid, which is conducive to the growth of mold. After long-term exposure to mold, the fireproof coating will become moldy, the adhesion will decrease, and the coating will crack and fall off. (3) The bonding strength of the coating is low. It is weak in resisting the strong airflow, wind pressure and resonance shock wave generated by high-speed traffic, and is prone to cracking. (4) The coating is relatively thick (20mm), and the construction is complicated and difficult to dry. (5) Poor decorative effect and more difficult to color match.

[0005] There is an urgent market demand for a thin-coat fireproof coating for tunnels and underground engineering projects that features a thin coating thickness, long fire resistance, good adhesion, waterproof and self-cleaning properties, mildew and antibacterial properties, environmental friendliness and non-toxicity, good decorative effect, and convenient construction. To meet market demand, this invention provides a tunnel fireproof, waterproof, and antibacterial coating, composed of a composite structure of a base coat, intermediate coat, and top coat. It features a thin coating (14mm), high fire resistance (over 2.5 hours), high bonding strength, good flexibility and crack resistance, excellent water resistance and waterproofing, freeze-thaw resistance, mildew and antibacterial properties, negative ion release, and environmental friendliness. It is suitable for coating protection of various tunnels, military mountain cave storage depots, and military and civilian underground engineering projects. Summary of the Invention

[0006] The purpose of this invention is to provide a composition and preparation method of a tunnel fireproof, waterproof and antibacterial coating with high bonding strength and compressive strength, good flexibility and crack resistance, fireproof, waterproof, self-cleaning, mildew-proof, bactericidal and bacteriostatic properties, release of negative ions, reflection of infrared heat, green environmental protection and easy construction.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a tunnel fireproof, waterproof and antibacterial coating and its preparation method, wherein the composite coating consists of three layers: a base coating, a middle coating and a top coating. The base coating is a tunnel fireproof and mildew-proof base coating, the middle coating is a tunnel fireproof and mildew-proof coating, and the top coating is a fireproof, waterproof and mildew-proof nano-ceramic coating.

[0008] Preferably, the sealing coating consists of the following components by weight: 40-50 parts of tunnel fireproof and mildew-proof coating, 20-30 parts of VAE emulsion, and 20-30 parts of deionized water.

[0009] Preferably, the intermediate coating layer, by weight, comprises the following components: 30-40 parts silicate cement, 5-10 parts high-alumina cement, 1-5 parts redispersible polymer powder, 0.1-0.5 parts hydroxypropyl methylcellulose, 0.01-0.05 parts sodium gluconate, 0.01-0.05 parts accelerator, 0.1-0.2 parts air-entraining agent, 0.1-0.5 parts water-repellent agent, and 0.1-0.5 parts water-reducing agent. 2 parts, aluminum silicate fiber 2-6 parts, enhanced multifunctional maifan stone powder 6-12 parts, ceramic hollow microspheres 5-10 parts, expanded vermiculite 6-12 parts, vitrified microspheres 10-15 parts, expandable graphite 1-5 parts, antimony trioxide 1-5 parts, aluminum hydroxide 1-5 parts, magnesium hydroxide 1-5 parts, zinc borate 1-5 parts, ammonium polyphosphate 1-2 parts, melamine 1-5 parts, dipentaerythritol 1-2 parts.

[0010] Preferably, the surface coating consists of the following components by weight: 40-60 parts of water-based inorganic nano-ceramic binder, 0.3-0.8 parts of wetting and dispersing agent, 0.1-0.4 parts of defoamer, 1-2 parts of rheology modifier, 2-5 parts of rutile titanium dioxide, 2-5 parts of potassium hexatitanate whiskers, 8-12 parts of synergistic multifunctional maifanite powder, 5-10 parts of hollow ceramic microspheres, 2-5 parts of chromium trioxide, 3-6 parts of ultrafine yttrium-stabilized zirconium oxide powder, 2-6 parts of aluminum oxide powder, and 10-20 parts of deionized water.

[0011] Firstly, step one: Preparation method of enhanced multifunctional maifan stone powder: Add low-viscosity quantitative 300-mesh Chinese maifan stone powder and quantitative nano multifunctional coating additives to a planetary ball mill jar, adjust the ball-to-material ratio to 1:1, rotate at 400 rpm, and mill for 1 hour. Discharge the material to obtain enhanced multifunctional maifan stone powder. Step two: Preparation of tunnel fireproof and mildew-proof coating: First, add ceramic hollow microspheres and aluminosilicate fibers to a powder mixer for mixing and dispersion. After the aluminosilicate fibers are evenly dispersed, add cement, enhanced multifunctional maifan stone powder, and redispersible adhesive. The powder and various additives are added, followed by expandable graphite, antimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate, ammonium polyphosphate, melamine, and dipentaerythritol. After stirring for 15-20 minutes until uniform, expandable vermiculite and vitrified microspheres are added, and the mixture is stirred for 5 minutes before being discharged to obtain a powdered tunnel fireproof and mildew-proof coating. Step three involves mixing the powdered tunnel fireproof and mildew-proof coating with water at a mass ratio of 1:0.7-1. The mixture is mechanically stirred into a uniform paste, and finally, multiple coats are applied using spraying or scraping methods to achieve a coating thickness of 12mm, which is the intermediate coat.

[0012] Preferably, the aqueous inorganic nano-ceramic binder is composed of the following components by mass: 35-45 parts potassium silicate solution, 20-30 parts silica sol, 2-3 parts MMT montmorillonite gel, 1-3 parts silane coupling agent KH-550, 15-20 parts 20% potassium hydroxide aqueous solution, and 15-20 parts deionized water.

[0013] Preferred method for preparing water-based inorganic nano-ceramic binder: Step 1: Add potassium silicate solution to a mixing tank and stir at 1000 rpm. When the temperature reaches 35-40℃, adjust the stirring speed to 1200-1500 rpm and add silica sol, continuing stirring for 25-30 minutes. Then add montmorillonite gel, increase the stirring speed to 2500 rpm and stir for 20 minutes. When the liquid temperature reaches 50-60℃, add silane coupling agent dropwise, adjust the stirring speed to 1600 rpm and stir for 25 minutes. Pour potassium hydroxide aqueous solution into the mixing tank, add deionized water, disperse evenly, and let stand for 20-30 minutes. Filter through a 200-mesh sieve. Filtration; Step 2, Preparation method of fireproof, waterproof and mildew-proof nano-ceramic coating: Add deionized water to the dispersion tank, add wetting and dispersing agent, rutile titanium dioxide, potassium hexatitanate whiskers, synergistic multifunctional maifanite powder, chromium trioxide, ultrafine yttrium-stabilized zirconium oxide powder and aluminum trioxide powder while stirring at 300 r / min, disperse at high speed for 30 min, and grind to a fineness of less than 10 μm to form pigment slurry; pour the pigment slurry into the paint mixing tank, add water-based inorganic nano-ceramic binder, hollow ceramic microspheres, defoamer and rheology modifier while stirring at 300 r / min, stir for 30 min, filter and package; Step 3: Apply by spraying or rolling, with a dry coating thickness of 0.2-0.5 mm.

[0014] Preferred is a composite coating for tunnel fireproofing, waterproofing, and antibacterial coating, consisting of a base coat, a middle coat, and a top coat, with a thickness of 12-12.5 mm and a fire resistance limit of 2.5 hours or more.

[0015] The technical effects and advantages of this invention are as follows: The composite coating of this invention has high bonding strength, compressive strength, flexibility, crack resistance, and frost resistance, and has excellent fire resistance, waterproof and seepage-proof properties, mildew and antibacterial properties, antifouling and self-cleaning properties, release of negative ions, and green environmental protection properties. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] This invention provides a tunnel fireproof, waterproof and antibacterial coating and its preparation method. The tunnel fireproof, waterproof and antibacterial coating composite coating is composed of a base coating, a middle coating and a top coating composite system.

[0018] The bottom sealing coating is a tunnel fireproof and mildew-proof sealing coating; the middle coating is a tunnel fireproof and mildew-proof coating; and the top coating is a fireproof, waterproof, and mildew-proof nano-ceramic coating.

[0019] The following provides a detailed description of the invention, specifically the formulations and preparation methods of the tunnel fireproof and mildew-proof sealing coating, the tunnel fireproof and mildew-proof coating, and the fireproof, waterproof, and mildew-proof nano-ceramic coating.

[0020] To address the aforementioned technical problems, this invention provides a formulation and preparation method for a tunnel fireproof and mildew-proof sealing coating: By mass percentage, it comprises the following components: 40-50% tunnel fireproof and mildew-proof coating, 20-30% VAE emulsion, and 20-30% deionized water. The components are mixed and stirred evenly at the construction site.

[0021] Application methods include spraying and roller coating, with a dry film thickness of 50-80µm.

[0022] To solve the above-mentioned technical problems, embodiments of the present invention provide a composition of a tunnel fireproof and mildew-proof coating: by mass percentage, it includes the following components: 30-40% 42.5R silicate cement, 5-10% C50 high-alumina cement, 1-5% redispersible polymer powder 5010N, 0.1-0.5% hydroxypropyl methylcellulose (70,000-100,000 units), 0.01-0.05% sodium gluconate, 0.01-0.05% accelerator Li2CaSO4, 0.1-0.2% air-entraining agent LP-WI, and hydrophobic... SEA-800.1-0.5, water-reducing agent SM0.1-0.2, aluminum silicate fiber (3-5mm) 2-6, multifunctional maifan stone powder 6-12, ceramic hollow microspheres 200 mesh 5-10, expanded vermiculite 6-12, vitrified microspheres 10-15, expandable graphite 1-5, antimony trioxide 1-5, aluminum hydroxide 1-5, magnesium hydroxide 1-5, zinc borate 1-5, ammonium polyphosphate (degree of polymerization > 1000) 1-2, melamine 1-5, dipentaerythritol 1-2.

[0023] Preparation method of tunnel fireproof and mildew-proof coating: Step 1, preparation method of enhanced multifunctional maifan stone: add low viscosity quantitative 300 mesh maifan stone powder and quantitative nano multifunctional coating additive into planetary ball mill jar, adjust the ball-to-material ratio to 1:1, rotate at 400 y / min, ball mill for 1 h, discharge the material, and obtain enhanced multifunctional maifan stone powder.

[0024] Enhancement Mechanism: The mechanochemical effect produced by ball milling is as follows: During the ball milling process, the maifan stone generates heat energy, and the particles develop towards amorphous shape, greatly reducing the particle size. The various metal elements contained in maifan stone have electrophilic properties. When maifan stone is subjected to strong mechanical action, a large amount of heat energy is generated, the lattice size is greatly reduced and distortion occurs, the surface is activated, and strong electrostatic adsorption is generated. At the same time, the nano-multifunctional materials also undergo lattice distortion and surface activation under mechanical effects. The activated nanoparticles are easily adsorbed by the micropores of maifan stone, forming multifunctional maifan stone powder with enhanced effects such as sterilization, deodorization, release of negative ions, and emission of far-infrared rays.

[0025] Step two, preparation of tunnel fireproof and mildew-proof coating: First, add ceramic hollow microspheres and aluminum silicate fiber to a powder mixer for mixing and dispersion. After the aluminum silicate fiber is evenly dispersed, add cement, enhanced multifunctional maifan stone powder, redispersible adhesive powder and various additives. Then add expandable graphite, antimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate, ammonium polyphosphate, melamine, and dipentaerythritol. Stir for 15-20 minutes until uniform. Then add expanded vermiculite and vitrified microspheres. Stir for 5 minutes and then discharge to obtain powdered tunnel fireproof and mildew-proof coating.

[0026] Construction mixing ratio: powdered tunnel fireproof and mildew-proof coating: water = 1:0.7-1 (mass ratio), mechanically stir into a uniform paste.

[0027] The coating is applied in multiple coats using spraying and scraping methods, with a thickness of 12mm, which is the intermediate coat.

[0028] To solve the above-mentioned technical problems, embodiments of the present invention provide a composition and preparation method of a fireproof, waterproof, and mildew-proof nano-ceramic coating: the fireproof, waterproof, and mildew-proof nano-ceramic coating comprises, by mass percentage, the following components: 40-60% water-based inorganic nano-ceramic binder, 0.3-0.8% wetting and dispersing agent, 0.1-0.4% defoamer, 1-2% rheology modifier, 2-5% rutile titanium dioxide, 2-5% potassium hexatitanate whiskers, 8-12% synergistic multifunctional maifanite powder, 5-10% hollow ceramic microspheres, 2-5% chromium trioxide, 3-6% ultrafine yttrium-stabilized zirconium oxide powder, 2-6% aluminum oxide powder, and 10-20% deionized water.

[0029] Preparation method of fireproof, waterproof and mildew-proof nano-ceramic coating: Step 1, composition and preparation method of water-based inorganic nano-ceramic binder; Step 2, preparation method of synergistic multifunctional maifanite powder; Step 3, preparation method of fireproof, waterproof and mildew-proof nano-ceramic coating.

[0030] Step 1: Composition and preparation method of water-based inorganic nano-ceramic binder; Composition of water-based inorganic nano-ceramic binder: potassium silicate solution 35-45, silica sol 20-30, MMT montmorillonite gel (8% aqueous solution) 2-3, silane coupling agent KH-5501-3 20% potassium hydroxide aqueous solution 15-20, deionized water 15-20.

[0031] Preparation method of water-based inorganic nano-ceramic binder: Add potassium silicate solution to a stirring tank and stir at 1000 r / min. When the temperature reaches 35-40℃, adjust the stirring speed to 1200-1500 r / min and slowly add silica sol and continue stirring for 25-30 min. Then slowly add montmorillonite gel and increase the stirring speed to 2500 r / min and keep stirring for 20 min. When the liquid temperature reaches 50-60℃, slowly add silane coupling agent and adjust the stirring speed to 1600 r / min and stir for 25 min. Pour potassium hydroxide aqueous solution into the stirring tank, add deionized water, disperse evenly, keep warm and stand for 20-30 min, and filter with a 200 mesh sieve.

[0032] Step two, the preparation method of the enhanced multifunctional maifanite powder, is the same as the preparation method of the enhanced multifunctional maifanite in this instruction manual.

[0033] Step 3, Preparation method of fireproof, waterproof and mildew-proof nano-ceramic coating: Add deionized water to a dispersion tank, and add wetting and dispersing agent, rutile titanium dioxide, potassium hexatitanate whiskers, synergistic multifunctional maifanite powder, chromium trioxide, ultrafine yttrium-stabilized zirconium oxide powder and aluminum trioxide powder while stirring at 300 r / min. Disperse at high speed for 30 min, and grind to a fineness of less than 10 μm using a sand mill to form a pigment slurry. Pour the pigment slurry into a paint mixing tank, and add water-based inorganic nano-ceramic binder, hollow ceramic microspheres, defoamer and rheology modifier while stirring at 300 r / min. Stir for 30 min, filter and package.

[0034] Apply by spraying or rolling, with a dry film thickness of 0.2-0.5mm.

[0035] The innovation of this invention patent lies in its composition and preparation method of a tunnel fireproof and mildew-proof coating: It uses organic redispersible polymer powder modified with high-strength silicate cement / high-alumina cement as a binder; porous, multifunctional maifanite powder, ceramic hollow microspheres, expanded vermiculite, and vitrified microspheres as fireproof and heat-insulating fillers; ammonium polyphosphate (APP), melamine (MEL), and pentaerythritol (PER) as PNC organic foaming fillers; expanded graphite as inorganic foaming fillers; antimony trioxide, aluminum hydroxide, magnesium hydroxide, and zinc borate as flame-retardant and smoke-suppressing fillers; and aluminum silicate fiber as fireproof and crack-resistant fillers. With the combined use of various functional additives, a powdered tunnel fireproof, waterproof, mildew-proof, negative ion-releasing, and environmentally friendly coating is prepared. When the coating thickness is 12mm, the fire resistance limit exceeds 120 minutes.

[0036] Innovation Point Two: Maifan stone possesses a unique porous, sponge-like structure. One gram of maifan stone has a surface area of ​​several hundred square meters, 20,000 times that of the same amount of activated carbon. Maifan stone itself can adsorb, decompose, and remove various harmful substances, such as amines, chlorine, mercury, cadmium, cyanide, Staphylococcus aureus, Escherichia coli, bacteria, and various pathogens. Through the mechanochemical effect of a high-energy ball mill, multifunctional nanomaterials with bactericidal, deodorizing, negative ion-releasing, and far-infrared-emitting properties are adsorbed into the micropores of the maifan stone particles, forming a synergistic multifunctional maifan stone with slow-release and long-lasting effects. The porous, sponge-like structure of maifan stone also provides thermal insulation properties.

[0037] Innovation Point 3: The film-forming material of the fireproof, waterproof and mildew-proof nano-ceramic coating is a self-made water-based inorganic nano-ceramic binder, which has the characteristics of self-forming film at room temperature, high hardness (6-7H), high adhesion (level 1), impact resistance (50cm), water resistance (no change after 30 days), high temperature resistance (1000℃), flexibility (1mm), and thermal shock resistance (10 times of rapid cooling from 1000℃ to room temperature is 1 time) without abnormality. A fireproof, waterproof, and mildew-resistant nano-ceramic coating was prepared using a self-made water-based inorganic nano-ceramic binder as the film-forming agent, and rutile titanium dioxide, potassium hexatitanate whiskers, synergistic multifunctional maifanite powder, hollow ceramic microspheres, chromium trioxide, ultrafine yttrium-stabilized zirconium oxide powder, and aluminum trioxide powder as fillers, with the aid of additives. The coating film possesses fireproof, waterproof, mildew-resistant, and antibacterial properties, releases negative ions, and exhibits excellent thermal infrared reflectivity, reaching 92%. In the event of a fire, it can reduce the surface temperature of the applied intermediate coating layer by approximately 20%. This increases the fire resistance limit of the tunnel fireproof composite coating of this invention to over 2.5 hours.

[0038] The beneficial effects of the technical solution are as follows: the tunnel fireproof, waterproof and antibacterial coating composite coating consists of a tunnel fireproof and mildew-proof sealing coating as the bottom coating, a tunnel fireproof and mildew-proof coating as the intermediate coating, and a fireproof, waterproof and mildew-proof nano-ceramic coating as the top coating, forming a three-layer composite structure system.

[0039] The aforementioned tunnel fireproof and mildew-proof sealing coating has high adhesion, excellent waterproofness, flexibility, and strong sealing properties on reinforced concrete substrates.

[0040] The aforementioned tunnel fireproof and mildew-resistant coating, serving as a mid-coat with a thickness of approximately 12mm, is a crucial primary coating for tunnel fire prevention. The tunnel fireproof and mildew-resistant coating prepared according to this invention, tested by the Tianjin Fire Inspection Center, fully meets conventional performance standards and exhibits a fire resistance exceeding 2 hours.

[0041] The test results are as follows: Test Item | Standard Requirements | Test Results | State in Container | Uniform after stirring, no lumps | Compliant | Workability | Easy to apply | Compliant | Surface Drying Time ≤ 54 | Alkali Resistance [Immersed in saturated Ca(OH2) solution for 24h] | No cracking, no blistering, no peeling, slight loss of gloss and discoloration allowed | 48h | No abnormalities | Cold and heat cycling resistance 15 cycles | No cracking or peeling | Compliant | Bond Strength / MPa ≥ 0.2 1.4 | Water Resistance (Immersed for 24h) | No cracking, no blistering, no peeling, slight loss of gloss and discoloration allowed | 96h | No abnormalities | Scrub Resistance 1000 cycles | No bare base | 2000 cycles | No bare base | Stain Resistance ≤ 15 | 13 | Fire Resistance Time / min | 60 120 The table, tested by the China Building Materials Academy Testing Center, shows the following performance characteristics in terms of anti-mold, antibacterial, deodorizing, and negative ion release: Test Item | Relevant Data Table | Test Item | Test Result | Standard Basis | Antibacterial | 99.5 HG / T3950-2007 | Antibacterial Durability | 99.0 HG / T3950-2007 | Anti-mold | Grade | 0 HG / T3950-2007 | Anti-mold Durability | Grade | 0 HG / T3950-2007 | Formaldehyde Purification Efficiency | % | 85 JG / T1074-2008 | Negative Ion Generation | pcs / s.cm² | 1,140 JG / T1016-2006 | Far-Infrared Emissivity | % | 92- The fireproof, waterproof, and mildew-resistant nano-ceramic coating described in the table, used as a topcoat, provides both protection and decoration. With a coating thickness of 0.2-0.5mm, it possesses excellent fire resistance, water resistance, stain resistance, self-cleaning properties, infrared reflectivity, mildew resistance, antibacterial properties, and negative ion release. In the event of a fire, the topcoat acts as the first line of fire protection, significantly delaying the heating time of the intermediate fireproof layer and improving the fire resistance limit of the composite fireproof layer through its non-combustible nature and infrared reflectivity.

[0042] Performance of Fireproof, Waterproof, and Mildew-resistant Nano-ceramic Coating: Test Item Performance Index Table Test Item Performance Index Solid Content (Unit: %) 55.0 Drying Time (Unit: h) 24.0 Water Resistance (Unit: h) 100.0 Impermeability (Unit: h) 100.0 Flexural Strength (Unit: pma) 20.0 Tear Strength (Unit: pma) 25.0 Compressive Strength (Unit: pma) 30.0 Pencil Hardness (Unit: H) 6.0 Adhesion (Cross-cut Test) 100 / 100 Graffiti Resistance Water-based and oil-based pen graffiti is easy to apply. Wipe off resistance to thermal shock without cracking; Alkali resistance (3% NaOH, 2h): No abnormality; Acid resistance (30% H2SO4, 2h): No abnormality; MEK wiping resistance: No abnormality; Heat resistance: Above 1000℃; Salt spray resistance (unit: h): 3000.0; Artificial aging resistance (unit: h): 1000.0; Thermal infrared reflectivity (unit: %): 92.0; Cooling effect of the coating medium: 20.0%; Antibacterial properties (unit: %): 99.0; Antifungal properties (unit: grade): 0.0; Negative ion generation (unit: ions / s.cm²): 1050.0 To make the technical problem to be solved, the technical solution and advantages of the present invention clearer, a detailed description will be given below with reference to specific examples.

[0043] The embodiments of this invention patent provide the composition of a tunnel fireproof, waterproof and antibacterial coating and its preparation method.

[0044] The tunnel fireproof, waterproof and antibacterial composite coating consists of a base coat, intermediate coat and top coat.

[0045] The bottom sealing coating is a tunnel fireproof and mildew-proof sealing coating; the middle coating is a tunnel fireproof and mildew-proof coating; and the top coating is a fireproof, waterproof, and mildew-proof nano-ceramic coating. The following is a detailed description of the invention, providing a detailed explanation of the formulation composition and preparation method of the tunnel fireproof and mildew-proof sealing coating, the tunnel fireproof and mildew-proof coating, and the fireproof, waterproof, and mildew-proof nano-ceramic coating.

[0046] To address the aforementioned technical problems, embodiments of this invention provide a composition and preparation method for a tunnel fireproof and mildew-proof sealing coating: Preferably, by mass percentage, it comprises the following components: 40% tunnel fireproof and mildew-proof coating, 30% VAE emulsion, and 30% deionized water. The components are mixed and stirred evenly at the construction site.

[0047] Application methods include spraying and roller coating, with a dry film thickness of 50-80µm.

[0048] To solve the above-mentioned technical problems, embodiments of the present invention provide a composition for a tunnel fireproof and mildew-proof coating: preferably, by mass percentage, it includes the following components: 32-40 parts of 42.5R silicate cement, 5-8 parts of C50 high-alumina cement, 1-5 parts of redispersible polymer powder 5010N, 0.1-0.5 parts of hydroxypropyl methylcellulose (70,000-100,000 units), 0.01-0.05 parts of sodium gluconate, 0.01-0.05 parts of accelerator Li2CaSO4, and 0.1-0.2 parts of air-entraining agent LP-WI. Water-repellent agent SEA-800.1-0.5, water-reducing agent SM0.1-0.2, aluminum silicate fiber (3-5mm) 2-5, synergistic multifunctional maifan stone powder 6-10, ceramic hollow microspheres 200 mesh 5-8, expanded vermiculite 6-10, vitrified microspheres 10-12, expandable graphite 1-5, antimony trioxide 1-5, aluminum hydroxide 1-5, magnesium hydroxide 1-5, zinc borate 1-5, ammonium polyphosphate (degree of polymerization > 1000) 1-2, melamine 1-5, dipentaerythritol 1-2.

[0049] Preparation method of tunnel fireproof and mildew-proof coating: Step 1, preparation method of enhanced multifunctional maifan stone: add a certain amount of 300 mesh maifan stone powder and a certain amount of nano multifunctional coating additive into a planetary ball mill jar, adjust the ball-to-material ratio to 1:1, rotate at 400 y / min, and ball mill for 1 hour, then discharge the material to obtain enhanced multifunctional maifan stone powder.

[0050] Step 2, Preparation of tunnel fireproof and mildew-proof coating: First, add ceramic hollow microspheres and aluminum silicate fiber to a powder mixer for mixing and dispersion. After the aluminum silicate fiber is evenly dispersed, add cement, enhanced multifunctional maifan stone powder, redispersible adhesive powder and various additives. Then add expandable graphite, antimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate, ammonium polyphosphate, melamine, and dipentaerythritol. Stir for 15-20 minutes until uniform. Then add expanded vermiculite and vitrified microspheres. Stir for 5 minutes and then discharge to obtain powdered tunnel fireproof and mildew-proof coating.

[0051] Construction mixing ratio: powdered tunnel fireproof and mildew-proof coating material: water = 1:0.7-1 (mass ratio), mechanically stir into a uniform paste.

[0052] The coating is applied by spraying or scraping, in multiple coats, with a thickness of 12mm, which is the intermediate coat.

[0053] To solve the above-mentioned technical problems, embodiments of this invention provide a composition and preparation method of a fireproof, waterproof, and mildew-proof nano-ceramic coating: the fireproof, waterproof, and mildew-proof nano-ceramic coating preferably comprises, by mass percentage, the following components: 45-55% water-based inorganic nano-ceramic binder, 0.3-0.8% wetting and dispersing agent, 0.1-0.4% defoamer, 1-2% rheology modifier, 2-5% rutile titanium dioxide, 2-5% potassium hexatitanate whiskers, 8-10% synergistic multifunctional maifanite powder, 5-10% hollow ceramic microspheres, 2-5% chromium trioxide, 3-6% ultrafine yttrium-stabilized zirconium oxide powder, 2-6% aluminum oxide powder, and 10-20% deionized water.

[0054] Preparation method of fireproof, waterproof and mildew-proof nano-ceramic coating: Step 1, composition and preparation method of water-based inorganic nano-ceramic binder; Step 2, preparation method of synergistic multifunctional maifanite powder; Step 3, preparation method of fireproof, waterproof and mildew-proof nano-ceramic coating.

[0055] Step 1: Composition and preparation method of water-based inorganic nano-ceramic binder; Composition of water-based inorganic nano-ceramic binder: potassium silicate solution 35-45, silica sol 20-30, MMT montmorillonite gel (8% aqueous solution) 2-3, silane coupling agent KH-5501-3 20% potassium hydroxide aqueous solution 15-20, deionized water 15-20.

[0056] Preparation method of water-based inorganic nano-ceramic binder: Add potassium silicate solution to a stirring tank and stir at 1000 r / min. When the temperature reaches 35-40℃, adjust the stirring speed to 1200-1500 r / min and slowly add silica sol and continue stirring for 25-30 min. Then slowly add montmorillonite gel and increase the stirring speed to 2500 r / min and keep stirring for 20 min. When the liquid temperature reaches 50-60℃, slowly add silane coupling agent and adjust the stirring speed to 1600 r / min and stir for 25 min. Pour potassium hydroxide aqueous solution into the stirring tank, add deionized water, disperse evenly, keep warm and stand for 20-30 min, and filter with a 200 mesh sieve.

[0057] Step two, the preparation method of the enhanced multifunctional maifanite powder, is the same as the preparation method of the enhanced multifunctional maifanite in this instruction manual.

[0058] Step 3, Preparation method of fireproof, waterproof and mildew-proof nano-ceramic coating: Add deionized water to a dispersion tank, and add wetting and dispersing agent, rutile titanium dioxide, potassium hexatitanate whiskers, synergistic multifunctional maifanite powder, chromium trioxide, ultrafine yttrium-stabilized zirconium oxide, and aluminum trioxide powder while stirring at 300 r / min. Disperse at high speed for 30 min, and grind to a fineness of less than 10 μm using a sand mill to form a pigment slurry. Pour the pigment slurry into a paint mixing tank, and add water-based inorganic nano-ceramic binder, hollow ceramic microspheres, defoamer, and rheology modifier while stirring at 300 r / min. Stir for 30 min, filter, and package.

[0059] Apply by spraying or rolling, with a dry coating thickness of 0.2-0.5mm.

[0060] Description of raw materials for the base coating - tunnel fireproof and mildew-proof sealing coating: In the examples, the VAE emulsion, namely ethyl acetate-ethylene copolymer emulsion, has the outstanding characteristics of excellent adhesion to various substrates, excellent alkali and water resistance of the coating film, and excellent flexibility.

[0061] In this embodiment, the tunnel fireproof and mildew-proof coating is a powdered tunnel fireproof and mildew-proof coating that serves as a mid-coat layer.

[0062] Description of raw materials for intermediate coating - tunnel fireproof and mildew-proof coating: Tunnel fireproof and mildew-proof coating is composed of redispersible adhesive powder / cement binder system, additive system, inorganic fireproof and heat-insulating filler system, inorganic flame-retardant and smoke-eliminating composite system, and organic-inorganic expansion foaming system.

[0063] In the embodiments, the redispersible adhesive powder / cement binder system is composed of 42.5R silicate cement, C50 high-alumina cement, and redispersible adhesive powder 5010N.

[0064] In the embodiments, the 42.5R silicate cement, an early-strength silicate cement, has the characteristics of high early strength, suitable for setting and hardening; good frost resistance, wear resistance, impermeability, and corrosion resistance; good workability and water retention; good compatibility with water-reducing agents; high later strength; and low heat of hydration.

[0065] In this embodiment, the C50 high-alumina cement, an aluminate refractory cement, possesses characteristics such as high temperature resistance, rapid setting time, high strength, and crack resistance. Combining silicate cement and high-alumina cement in an appropriate ratio can improve the early setting, rapid drying, fire resistance, water resistance, and strength of powdered tunnel fireproof coatings.

[0066] In the embodiments, the redispersible polymer powder 5010N, VINNAPAS® 5010N redispersible latex powder from Wacker Chemie, Germany, is a saponification-resistant redispersible vinyl acetate / ethylene copolymer powder, suitable for use with cement to form polymer-modified flexible cementitious adhesives, and has excellent adhesion, flexural strength, plasticity and workability.

[0067] Redispersible polymer powder is a powder formed by spray drying of a polymer emulsion. It can be re-emulsified when mixed with water, retaining the same properties as the original emulsion. Its dry film exhibits excellent flexibility and adhesion. Adding redispersible polymer powder to cement can form an organic-inorganic dual-adhesion structure system. When the dosage of redispersible polymer powder reaches a certain level, the polymer film forms a spatial network structure within the tunnel fireproof coating, thereby enhancing the compressive and tensile strength of the fireproof coating, improving its flexibility and water resistance, increasing its adhesion and workability, and reducing its internal stress, elastic modulus, and drying shrinkage.

[0068] In the embodiments, the additive system consists of hydroxypropyl methylcellulose, sodium gluconate, coagulant li2CaSO4, air-entraining agent LP-WI, water-repellent agent SEA-80, and water-reducing agent SM.

[0069] In this embodiment, the hydroxypropyl methylcellulose is a water-retaining agent. Cement is a rigid inorganic cementitious material, and its crystallization and curing time upon contact with water is lengthy, requiring a certain moisture content to be maintained during the curing process. Because the moisture in tunnel fireproof coatings is quickly absorbed by the wall surface during application, it affects the hydration and curing strength of the cement. The addition of the water-retaining agent hydroxypropyl methylcellulose utilizes its strong water absorption and good water retention properties to extend the open time and improve workability, adhesion, wetting properties, and crack resistance.

[0070] In the embodiments, the sodium gluconate, a white powder, is used as a high-efficiency retarder and high-efficiency water-reducing agent in this polymer cement-based tunnel fireproof coating.

[0071] In the embodiments, the accelerator Li2CaSO4, gypsum dihydrate, is used as an accelerator in this polymer cement-based tunnel fireproof coating.

[0072] In this embodiment, the air-entraining agent LP-WI is added in appropriate amounts to the polymer cement-based tunnel fireproof coating. This can improve the fluidity and plasticity of the polymer cement-based tunnel fireproof coating, reduce bleeding and segregation, increase flexural strength, increase microporous structure, reduce the thermal conductivity of the coating, and improve thermal insulation.

[0073] In the embodiments, the water-repellent agent SEA-80 is a sodium methylsilanol waterproofing agent. Adding an appropriate amount of water-repellent agent SEA-80 to this polymer cement-based tunnel fireproof coating can enhance the waterproofness, moisture resistance, and impermeability of the tunnel fireproof and mildew-proof coating.

[0074] In this embodiment, the water-reducing agent SM is a high-efficiency water-reducing agent for sulfonated melamine-formaldehyde resin. Adding an appropriate amount of SM to this polymer cement-based tunnel fireproof coating can improve its fluidity, early strength, and later strength.

[0075] In the embodiments, the inorganic fireproof and heat-insulating filler system is composed of aluminum silicate fiber, hollow ceramic microspheres, enhanced multifunctional maifan stone powder, expanded vermiculite, and vitrified microspheres.

[0076] In this embodiment, the aluminosilicate fiber, also known as ceramic fiber, possesses excellent flexibility, chemical stability, corrosion resistance, high-temperature resistance, and sound absorption properties. It also features high tensile strength, low thermal conductivity, low heat capacity, and low density. Adding an appropriate amount of aluminosilicate fiber to the polymer cement-based tunnel fireproof coating utilizes its random distribution within the coating to construct a three-dimensional network structure. This not only improves the porosity of the coating but also enhances its bonding strength, tensile strength, and flexibility and crack resistance.

[0077] In this embodiment, the hollow ceramic microspheres have a tiny porous hollow structure inside, and a hard outer shell composed of a fibrous hollow mesh structure on the surface, with a certain amount of static air inside the shell. The compressive strength is 4000-7000 kg / cm². 2 It has a thermal conductivity of 0.07-0.12 W / (m•K) and a heat resistance of up to 1500℃. It possesses advantages such as low density, large volume, low thermal conductivity, high compressive strength, low oil absorption, good self-flowing properties, resistance to high and low temperatures, corrosion resistance, sound insulation, radiation protection, low water absorption, and strong electrical insulation. It is a multifunctional, versatile, high-performance, and low-cost extender material. Adding an appropriate amount of hollow ceramic microspheres to polymer cement-based tunnel fireproof coatings improves the coating's thermal insulation and fire resistance.

[0078] In this embodiment, the enhanced multifunctional maifanite powder is a functional material formed by adsorbing nano-multifunctional coating additives onto maifanite powder. Maifanite is a natural silicate mineral; it is a composite mineral or medicinal rock that is non-toxic, harmless to organisms, and possesses certain biological activity. The main chemical components of maifanite are inorganic aluminosilicates, including SiO2, Al2O3, Fe2O3, FeO, MgO, CaO, K2O, Na2O, TiO2, P2O5, and MnO. It also contains all the macroelements required by animals, such as trace elements and rare earth elements, totaling approximately 58 kinds. Maifan stone possesses dual adsorption properties: firstly, its silicate composition provides excellent adsorption; secondly, its porous, sponge-like structure, largely composed of clay minerals like kaolinite, exhibits strong electrostatic attraction, resulting in a high adsorption capacity for heavy metal ions and harmful toxins. It boasts an adsorption rate exceeding 96% for harmful gases such as formaldehyde, benzene, and ammonia, as well as bacteria and E. coli in the air. This invention utilizes the porous structure and strong adsorption capacity of maifan stone to adsorb multifunctional nanomaterials with bactericidal, deodorizing, negative ion-releasing, and far-infrared-emitting properties into the micropores of fine maifan stone particles, forming a synergistic multifunctional maifan stone.

[0079] In this embodiment, the nano-multifunctional material is a composite of nano-bactericides, negative ions, and far-infrared materials using nanotechnology. Appearance: Light grayish-white powder; environmentally friendly and non-toxic; antibacterial activity: >99.%; negative ion release: >3000 ions / cm³. 3 Far-infrared emissivity: >90% In the embodiment, the expanded vermiculite is a complex layered fragment of iron and magnesium silicate, filled with countless tiny pores, with a dry density of 80-120 kg / m³. 3 With a thermal conductivity of 0.047–0.07 W / (mk), it is an excellent thermal insulation material. In the embodiment, the vitrified microspheres are made from acidic glassy lava minerals and processed by an electric furnace to form porous, vitrified, and spherical granular materials. Due to the surface vitrification, the particles have a certain strength, strong aging resistance and weather resistance, and excellent thermal insulation, fireproofing, sound absorption and heat preservation properties.

[0080] In the embodiments, the inorganic composite flame retardant and smoke-eliminating system is composed of antimony trioxide, aluminum hydroxide, magnesium hydroxide, and zinc borate.

[0081] In this embodiment, antimony trioxide, aluminum hydroxide, magnesium hydroxide, and zinc borate constitute an inorganic composite flame-retardant and smoke-suppressing system. Antimony trioxide, aluminum hydroxide, magnesium hydroxide, and zinc borate, through thermal decomposition and endothermic reaction, generate water vapor, which dilutes the flame and thus exerts their flame-retardant effect.

[0082] Aluminum hydroxide has an initial decomposition temperature of 250℃, while magnesium hydroxide has a decomposition temperature of 350℃, allowing for a gradient decomposition and endothermic effect. When their respective decomposition temperatures are reached, decomposition occurs, absorbing heat from the fire-retardant coating surface and releasing a large amount of moisture, diluting the oxygen on the coating surface. The resulting active alumina and active magnesium oxide adhere to the carbonized layer surface, preventing both oxygen entry and the escape of combustible gases, thus providing excellent smoke suppression. At 300℃, zinc borate decomposes, releasing water of crystallization, which acts as an endothermic cooling agent and dilutes oxygen. Zinc borate decomposes at high temperatures to form boron trioxide, and the boric acid produced during this high-temperature decomposition promotes the formation of a glassy carbonized layer, protecting it and inhibiting smoke generation.

[0083] In the embodiments, the organic-inorganic expandable foaming system is composed of expandable graphite, ammonium polyphosphate, melamine, and dipentaerythritol.

[0084] In this embodiment, the expandable graphite is an inorganic graphite product obtained by chemical or electrochemical treatment of natural flake graphite. It possesses properties such as lubricity, conductivity, flexibility, and chemical stability. When subjected to temperatures above 200°C, the compounds in its interlayer lattice absorb a large amount of heat and rapidly decompose, vaporize, and expand, ultimately expanding 150-200 times along the interlayer to form a sub-nanometer microporous structure. This results in a large number of "worm-like" carbonized particles, significantly increasing their surface area, surface free energy, surface activity, and adsorption capacity. These particles cross-link with the carbon layer generated by chemical expansion. The "worm-like" graphite carbonized particles adhere to the surface of the substrate and the interior of the carbon layer, acting as a cross-linked fiber and forming the backbone of the expansion system. This improves the residual carbon content of the fireproof coating and the activation energy during thermal degradation, thereby improving the microstructure of the foamed carbon layer.

[0085] In the embodiments, the ammonium polyphosphate, melamine, and pentaerythritol are used as catalysts. The ammonium polyphosphate, melamine as a foaming agent, and pentaerythritol as a carbonizing agent constitute an organic expanding foaming system. Expandable graphite, which also acts as a foaming agent, plasticizer, and carbonizing agent, is an inorganic expanding foaming material. Together, they constitute the expanding foaming system in the tunnel fireproof coating.

[0086] Specific embodiments of intermediate coating - tunnel fireproof and mildew-proof coating: Embodiments 1, 2, 3, and 4. Embodiments 1, 2, 3, and 4 of the present invention provide a composition and preparation method of a tunnel fireproof and mildew-proof coating: Composition of tunnel fireproof and mildew-proof coating: The raw material composition of the tunnel fireproof and mildew-proof coatings of Embodiments 1, 2, 3, and 4, by mass percentage, includes the following components, as shown in the table below: Raw material composition and dosage table Raw material name Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 42.5R Silicate cement 32.00 34.00 35.00 33.00C 50 High-alumina cement 8.00 6.00 5.00 6.00 Redispersible adhesive powder 2.00 3.00 4.00 5.00 Hydroxypropyl methylcellulose 0.30 0.40 0.50 0.40 Sodium gluconate 0.02 0.02 0.02 0.02 Accelerator Li2CaSO4 0.02 0.02 0.02 0.02 Air-entraining agent LP-WI 0.10 0.20 0.30 0.30 Water-repellent agent SEA-80 0.200. 200.300.40 Water-reducing agent SM 0.200.200.300.30 Aluminum silicate fiber 3.00 3.00 4.00 5.00 Synergistic multifunctional maifan stone powder 10.00 9.00 8.00 7.00 Ceramic hollow microspheres 5.00 5.00 6.00 7.00 Expanded vermiculite 10.00 9.00 7.00 8.00 Vitrified microspheres 11.00 12.00 10.00 7.00 Expandable graphite 2.0 03.00 4.00 5.00 Antimony trioxide 2.00 2.00 2.00 2.00 Aluminum hydroxide 2.00 2.00 2.00 2.00 Magnesium hydroxide 2.00 2.00 2.00 2.00 Zinc borate 3.00 3.00 3.00 3.00 Ammonium polyphosphate 3.00 3.00 3.00 3.00 Melamine 2.00 2.00 2.00 2.00 Dipentaerythritol 2.00 2.00 2.00 2.00 Preparation methods of tunnel fireproof and mildew-proof coatings in Examples 1, 2, 3, and 4: Step 1, preparation method of enhanced multifunctional maifan stone: Add a certain amount of 300-mesh maifan stone powder and a certain amount of nano multifunctional coating additives into a planetary ball mill jar, adjust the ball-to-material ratio to 1:1, rotate at 400 y / min, and ball mill for 1 hour, then discharge the material to obtain enhanced multifunctional maifan stone powder.

[0087] Step 2, Preparation of tunnel fireproof and mildew-proof coating: First, add ceramic hollow microspheres and aluminum silicate fiber to a powder mixer for mixing and dispersion. After the aluminum silicate fiber is evenly dispersed, add cement, enhanced multifunctional maifan stone powder, redispersible adhesive powder and various additives. Then add expandable graphite, antimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate, ammonium polyphosphate, melamine, and dipentaerythritol. Stir for 15-20 minutes until uniform. Then add expanded vermiculite and vitrified microspheres. Stir for 5 minutes and then discharge to obtain powdered tunnel fireproof and mildew-proof coating.

[0088] Construction mixing ratio: powdered tunnel fireproof and mildew-proof coating: water = 1:0.7-1 (mass ratio), mechanically stir into a uniform paste.

[0089] The coating is applied by spraying or scraping, in multiple coats, with a thickness of 12mm, which is the intermediate coat.

[0090] Topcoat - Fireproof, waterproof and mildew-proof nano-ceramic coating raw material description: The fireproof, waterproof and mildew-proof nano-ceramic coating is composed of water-based inorganic nano-ceramic binder, additives, pigments and fillers and water.

[0091] In this embodiment, the aqueous inorganic nano-ceramic binder is composed of potassium silicate solution, silica sol, MMT montmorillonite gel, silane coupling agent KH-550, 20% potassium hydroxide aqueous solution, and deionized water. Specifically, in this embodiment, the potassium silicate solution is selected with a solid content of 30%-35% and a modulus of 3-4.

[0092] In the embodiments, the silica sol is selected as having a solid content of 30%-35% and a particle size of 5-40nm.

[0093] In this embodiment, the MMT montmorillonite gel was prepared by adding 8 parts of montmorillonite to 92 parts of deionized water, stirring until homogeneous, and allowing it to stand for 24 hours. Montmorillonite is an additive with a nanosheet structure, with a crystal sheet spacing of about 1 nm. The sheet surface is mainly characterized by hydrogen bonds and charge interactions. The nanosheet structure has good adsorption capacity, reinforcing properties, and thixotropic properties.

[0094] In the embodiments, the silane coupling agent KH-550, 3-aminopropyltriethoxysilane, plays a modifying, reinforcing, and crosslinking role in the formulation preparation of the water-based inorganic nano-ceramic binder. The silane coupling agent hydrolyzes in water to obtain the corresponding silanol, which condenses into oligomers and reacts with potassium silicate / silica sol to form a network structure, thereby improving the water resistance of the binder and giving it hydrophobicity, high-temperature resistance, and room-temperature self-film-forming properties.

[0095] In the embodiments, the 20% potassium hydroxide aqueous solution plays a stabilizing role in the aqueous inorganic nano-ceramic binder.

[0096] In the embodiments, the additives in the aqueous inorganic nano-ceramic binder formulation include wetting and dispersing agent 8008, defoamer BYK-015, and rheology modifier BYK-420.

[0097] In the embodiments, the pigments and fillers in the aqueous inorganic nano-ceramic binder formulation include rutile titanium dioxide, potassium hexatitanate whiskers, synergistic multifunctional maifanite powder, hollow ceramic microspheres, chromium trioxide, ultrafine yttrium-stabilized zirconium dioxide, aluminum trioxide powder, and deionized water.

[0098] In the embodiments, the rutile titanium dioxide has the characteristics of high whiteness, strong hiding power, aging resistance, corrosion resistance, high temperature resistance, and high light and heat reflectance.

[0099] In the embodiments, the potassium hexatite whiskers have a composition of K2Ti6O. 13 The structure is an interlocking tunnel type, with K+ ions residing in the middle of the tunnels, exhibiting high stability. This gives potassium hexatite whiskers high-temperature sound absorption, chemical stability, insulation, infrared reflection, and excellent corrosion resistance. Potassium hexatite whiskers integrate structural heat insulation, physical heat insulation, and infrared reflection, with an infrared reflectivity greater than 95%. Its bulk density is 0.1-0.3 g / cm³, specific surface area is 11 m² / g, and mesopore size is 0.8-1.2 μm in diameter and 30-50 μm in length. It has low thermal conductivity (0.0534 W / (mK) at room temperature) and a negative temperature coefficient (the higher the temperature, the lower the thermal conductivity), with a thermal conductivity of 0.0174 W / (mK) at 760℃. It also has low infrared transmittance: in the wavelength range of 0.9-2.4 μm, a 0.25 μm thick potassium hexatitanate whisker has a transmittance of only 8.4%. Furthermore, it is non-toxic, harmless, has a long service life, can withstand high temperatures up to 1200℃, is acid and alkali resistant, wear-resistant, and insulating, and possesses good mechanical and physical properties. It is widely used in thermal insulation materials, friction materials, insulating materials, and refractory materials. It is an excellent functional filler for developing infrared reflective coatings and heat-resistant insulating coatings.

[0100] In this embodiment, the enhanced multifunctional maifanite powder is a functional material formed by adsorbing nano-multifunctional coating additives onto maifanite powder. Maifanite is a natural silicate mineral; it is a composite mineral or medicinal rock that is non-toxic, harmless to organisms, and possesses certain biological activity. The main chemical components of maifanite are inorganic aluminosilicates, including SiO2, Al2O3, Fe2O3, FeO, MgO, CaO, K2O, Na2O, TiO2, P2O5, and MnO. It also contains all the macroelements required by animals, such as trace elements and rare earth elements, totaling approximately 58 kinds. Maifan stone possesses dual adsorption properties: firstly, its silicate composition provides excellent adsorption; secondly, its porous, sponge-like structure, largely composed of clay minerals like kaolinite, exhibits strong electrostatic attraction, resulting in a high adsorption capacity for heavy metal ions and harmful toxins. It boasts an adsorption rate exceeding 96% for harmful gases such as formaldehyde, benzene, and ammonia, as well as bacteria and E. coli in the air. This invention utilizes the porous structure and strong adsorption capacity of maifan stone to adsorb multifunctional nanomaterials with bactericidal, deodorizing, negative ion-releasing, and far-infrared-emitting properties into the micropores of fine maifan stone particles, forming a synergistic multifunctional maifan stone.

[0101] In this embodiment, the nano-multifunctional material is a composite of nano-bactericides, negative ions, and far-infrared materials using nanotechnology. Appearance: Light grayish-white powder; environmentally friendly and non-toxic; antibacterial activity: >99.%; negative ion release: >3000 ions / cm³. 3 Far-infrared emissivity: >90%. In this embodiment, the hollow ceramic microspheres have a tiny porous hollow structure inside, and the surface is composed of a hard outer shell made of a fibrous hollow network structure, with a certain static air layer inside the shell. The compressive strength is 4000-7000 kg / cm², the thermal conductivity is 0.07-0.12 W / (m•k), and the heat resistance reaches 1500℃. It has advantages such as low density, large volume, low thermal conductivity, high compressive strength, low oil absorption, good self-flowing properties, resistance to high and low temperatures, corrosion resistance, sound insulation, radiation protection, low water absorption, and strong electrical insulation. It is a multifunctional, multi-purpose, high-performance, and low-cost extender material. Adding an appropriate amount of hollow ceramic microspheres to polymer cement-based tunnel fireproof coatings improves the coating's heat insulation and fire resistance.

[0102] In the embodiments, the chromium trioxide, a cubic or amorphous green powder, exhibits excellent heat resistance, remaining unchanged at temperatures up to 1000℃, and also demonstrates excellent resistance to acids and alkalis. It is extremely stable to light, atmosphere, and corrosive gases such as sulfur dioxide and hydrogen sulfide. It possesses high hiding power, relatively hard particle size, magnetic properties, and the ability to absorb and reflect infrared radiation.

[0103] In this embodiment, the ultrafine yttrium-stabilized zirconium dioxide (ZrO2) possesses properties such as high temperature resistance, chemical corrosion resistance, oxidation resistance, wear resistance, high coefficient of thermal expansion, and low heat capacity and thermal conductivity. Therefore, it is an ideal high-temperature refractory material, special ceramic material, abrasive material, and high-temperature insulation material. The ultrafine zirconium oxide coating can withstand temperatures up to 2200°C and exhibits exceptional optical properties, with a reflectivity of over 85% for ultraviolet long-wave, mid-wave, and infrared rays. After drying, the ultrafine particles tightly fill the gaps between the coating layers, forming a complete air insulation layer. Furthermore, its low thermal conductivity forces a longer heat transfer time within the coating, resulting in a low thermal conductivity and improved insulation performance. Simultaneously, the severely under-coordinated and oxygen-deficient surface of ultrafine zirconium oxide exhibits extremely high reactivity, readily bonding with oxygen on the surfaces of other materials in the coating, thereby improving the coating's density and physicochemical properties. Ultrafine zirconia has a spatial network structure and a large number of unsaturated residual bonds and hydroxyl groups in different states on its surface, which can generate good affinity with coating systems, thereby improving the suspension stability of coatings.

[0104] In this embodiment, the alumina powder is an α-alumina micro powder with a refractoriness of 1500℃ and a melting point of 2050℃. It is an active alumina micro powder produced by low-temperature phase inversion calcination of industrial alumina and aluminum hydroxide with additives, followed by grinding. It possesses characteristics such as high activity, low particle size, high melting point, good thermal stability, high hardness, high mechanical strength, good electrical insulation, strong corrosion resistance, and infrared reflection, making it a commonly used amphoteric oxide in high-temperature coatings.

[0105] Specific embodiments of the surface layer - fireproof, waterproof, and mildew-proof nano-ceramic coating: Embodiments 1, 2, 3, and 4. Embodiments 1, 2, 3, and 4 of the present invention provide a composition and preparation method of a surface layer - fireproof, waterproof, and mildew-proof nano-ceramic coating: Composition of the fireproof, waterproof, and mildew-proof nano-ceramic coating: Embodiments 1, 2, 3, and 4, by mass percentage, include the following components: See the table below for raw material embodiment data table Raw material name Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Water-based inorganic nano-ceramic binder 45.00 48.00 50.00 53.00 Wetting and dispersing agent 0.50 0.40 0.50 0.50 Defoamer 0.30 0.30 0.30 0.30 Rheology modifier 2.001 0.00 1.50 1.20 Rutile Titanium Dioxide 5.00 4.00 5.00 3.00 Potassium Hexatitanate Whiskers 3.00 4.00 5.00 4.00 Enhanced Multifunctional Maifan Stone Powder 10.00 8.00 7.00 7.00 Hollow Ceramic Microspheres 6.00 7.00 8.00 8.00 Chromium Trioxide 3.00 2.00 5.00 4.00 Ultrafine Yttrium Stabilized Zirconia Powder 5.00 4.00 3.00 4.00 Aluminum Trioxide Powder 5.00 3.00 4.00 3.00 Deionized Water 15.00 19.00 11.00 12.00 Preparation method of fireproof, waterproof and mildew-proof nano-ceramic coating: Step 1, composition and preparation method of water-based inorganic nano-ceramic binder; Step 2, preparation method of synergistic multifunctional maifanite powder; Step 3, preparation method of fireproof, waterproof and mildew-proof nano-ceramic coating.

[0106] Step 1: Composition and preparation method of water-based inorganic nano-ceramic binder; Composition of water-based inorganic nano-ceramic binder: potassium silicate solution 35-45, silica sol 20-30, MMT montmorillonite gel (8% aqueous solution) 2-3, silane coupling agent KH-5501-3 20% potassium hydroxide aqueous solution 15-20, deionized water 15-20.

[0107] Preparation method of water-based inorganic nano-ceramic binder: Add potassium silicate solution to a stirring tank and stir at 1000 r / min. When the temperature reaches 35-40℃, adjust the stirring speed to 1200-1500 r / min and slowly add silica sol and continue stirring for 25-30 min. Then slowly add montmorillonite gel and increase the stirring speed to 2500 r / min and keep stirring for 20 min. When the liquid temperature reaches 50-60℃, slowly add silane coupling agent and adjust the stirring speed to 1600 r / min and stir for 25 min. Pour potassium hydroxide aqueous solution into the stirring tank, add deionized water, disperse evenly, keep warm and stand for 20-30 min, and filter with a 200 mesh sieve.

[0108] Step two, the preparation method of the enhanced multifunctional maifanite powder, is the same as the preparation method of the enhanced multifunctional maifanite in this instruction manual.

[0109] Step 3, Preparation method of fireproof, waterproof and mildew-proof nano-ceramic coating: Add deionized water to a dispersion tank, and add wetting and dispersing agent, rutile titanium dioxide, potassium hexatitanate whiskers, synergistic multifunctional maifanite powder, chromium trioxide, ultrafine yttrium-stabilized zirconium oxide powder and aluminum trioxide powder while stirring at 300 r / min. Disperse at high speed for 30 min, and grind to a fineness of less than 10 μm using a sand mill to form a pigment slurry. Pour the pigment slurry into a paint mixing tank, and add water-based inorganic nano-ceramic binder, hollow ceramic microspheres, defoamer and rheology modifier while stirring at 300 r / min. Stir for 30 min, filter and package.

[0110] Apply by spraying or rolling, with a dry film thickness of 0.2-0.5mm.

[0111] The structure of the tunnel fireproof, waterproof and antibacterial composite coating: The tunnel fireproof, waterproof and antibacterial composite coating consists of a base coat, a middle coat and a top coat.

[0112] The bottom sealing coating is a tunnel fireproof and mildew-proof sealing coating; the middle coating is a tunnel fireproof and mildew-proof coating; and the top coating is a fireproof, waterproof, and mildew-proof nano-ceramic coating.

[0113] One preferred embodiment of the sealing coating—a fireproof and mildew-proof sealing coating for tunnels; four preferred embodiments of the intermediate coating—a fireproof and mildew-proof coating for tunnels; and four preferred embodiments of the topcoat—a fireproof, waterproof, and mildew-proof nano-ceramic coating.

[0114] Application of the composite coating system for tunnel fireproof, waterproof, and antibacterial coatings: With the base coat example remaining constant, the intermediate coat examples 1, 2, 3, and 4, and the top coat examples 1, 2, 3, and 4 can be compounded in a corresponding order to form four composite coating systems, or they can be cross-combined to create 12 different composite coating systems for tunnel fireproof, waterproof, and antibacterial coatings. The composite coating thickness is 12-12.5 mm, with a fire resistance limit of over 2.5 hours. The composite coating possesses high bonding strength, compressive strength, flexibility, crack resistance, and frost resistance, and exhibits excellent fire resistance, waterproofing, anti-mildew and antibacterial properties, anti-fouling and self-cleaning properties, negative ion release, and environmental friendliness.

[0115] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fireproof, waterproof, and antibacterial coating for tunnels, characterized in that: The composite coating consists of three layers: a base coating, a middle coating, and a top coating. The base coating is a tunnel fireproof and mildew-proof base coating, the middle coating is a tunnel fireproof and mildew-proof coating, and the top coating is a fireproof, waterproof, and mildew-proof nano-ceramic coating.

2. The tunnel fireproof, waterproof, and antibacterial coating according to claim 1, characterized in that: The sealing coating consists of the following components by weight: 40-50 parts of tunnel fireproof and mildew-proof coating, 20-30 parts of VAE emulsion, and 20-30 parts of deionized water.

3. The tunnel fireproof, waterproof, and antibacterial coating according to claim 1, characterized in that: The intermediate coating consists of the following components by weight: 30-40 parts silicate cement, 5-10 parts high-alumina cement, 1-5 parts redispersible polymer powder, 0.1-0.5 parts hydroxypropyl methylcellulose, 0.01-0.05 parts sodium gluconate, 0.01-0.05 parts accelerator, 0.1-0.2 parts air-entraining agent, 0.1-0.5 parts water-repellent agent, 0.1-0.2 parts water-reducing agent, 2-6 parts aluminosilicate fiber, 6-12 parts synergistic multifunctional maifan stone powder, 5-10 parts ceramic hollow microspheres, 6-12 parts expanded vermiculite, 10-15 parts vitrified microspheres, 1-5 parts expandable graphite, 1-5 parts antimony trioxide, 1-5 parts aluminum hydroxide, 1-5 parts magnesium hydroxide, 1-5 parts zinc borate, 1-2 parts ammonium polyphosphate, 1-5 parts melamine, and 1-2 parts dipentaerythritol.

4. The tunnel fireproof, waterproof, and antibacterial coating according to claim 1, characterized in that: The surface coating consists of the following components by weight: 40-60 parts of water-based inorganic nano-ceramic binder, 0.3-0.8 parts of wetting and dispersing agent, 0.1-0.4 parts of defoamer, 1-2 parts of rheology modifier, 2-5 parts of rutile titanium dioxide, 2-5 parts of potassium hexatitanate whiskers, 8-12 parts of synergistic multifunctional maifanite powder, 5-10 parts of hollow ceramic microspheres, 2-5 parts of chromium trioxide, 3-6 parts of ultrafine yttrium-stabilized zirconium oxide powder, 2-6 parts of aluminum oxide powder, and 10-20 parts of deionized water.

5. The preparation method of the tunnel fireproof, waterproof and antibacterial coating according to claim 3, characterized in that: Step 1: Preparation method of enhanced multifunctional maifan stone powder: Add low-viscosity quantitative 300-mesh Chinese maifan stone powder and quantitative nano multifunctional coating additive to a planetary ball mill jar, adjust the ball-to-material ratio to 1:1, rotate at 400 r / min, and ball mill for 1 hour. Discharge the material to obtain enhanced multifunctional maifan stone powder; Step 2: Preparation of tunnel fireproof and mildew-proof coating: First, add ceramic hollow microspheres and aluminosilicate fibers to a powder mixer for mixing and dispersion. After the aluminosilicate fibers are evenly dispersed, add cement, enhanced multifunctional maifan stone powder, redispersible adhesive powder, and... Various additives are added, along with expandable graphite, antimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate, ammonium polyphosphate, melamine, and dipentaerythritol. After stirring for 15-20 minutes until homogeneous, expandable vermiculite and vitrified microspheres are added, and the mixture is stirred for 5 minutes before being discharged to obtain a powdered tunnel fireproof and mildew-proof coating. Step three involves mixing the powdered tunnel fireproof and mildew-proof coating with water at a mass ratio of 1:0.7-1. The mixture is mechanically stirred into a uniform paste, and finally, multiple coats are applied using spraying or scraping methods to achieve a coating thickness of 12mm, which is the intermediate coat.

6. The method for preparing a tunnel fireproof, waterproof, and antibacterial coating according to claim 4, characterized in that: The aqueous inorganic nano-ceramic binder is composed of the following components by mass: 35-45 parts potassium silicate solution, 20-30 parts silica sol, 2-3 parts MMT montmorillonite gel, 1-3 parts silane coupling agent KH-550, 15-20 parts 20% potassium hydroxide aqueous solution, and 15-20 parts deionized water.

7. The preparation method of the tunnel fireproof, waterproof and antibacterial coating according to claim 6, characterized in that: Preparation method of water-based inorganic nano-ceramic binder: Step 1: Add potassium silicate solution to a stirring tank and stir at 1000 r / min. When the temperature reaches 35-40℃, adjust the stirring speed to 1200-1500 r / min and add silica sol, continuing to stir for 25-30 min. Then add montmorillonite gel, increase the stirring speed to 2500 r / min and keep stirring at this temperature for 20 min. When the liquid temperature reaches 50-60℃, add silane coupling agent dropwise, adjust the stirring speed to 1600 r / min and stir for 25 min. Pour potassium hydroxide aqueous solution into the stirring tank, add deionized water, disperse evenly, keep warm and let stand for 20-30 min, and filter through a 200-mesh sieve. Step 2: Preparation method of fireproof, waterproof and mildew-proof nano-ceramic coating: Add deionized water to the dispersion tank, and add wetting and dispersing agent, rutile titanium dioxide, potassium hexatitanate whiskers, synergistic multifunctional maifanite powder, chromium trioxide, ultrafine yttrium-stabilized zirconium oxide powder and aluminum trioxide powder while stirring at 300 r / min. Disperse at high speed for 30 min, and grind to a fineness of less than 10 μm using a sand mill to form a pigment slurry. Pour the pigment slurry into the paint mixing tank, and add water-based inorganic nano-ceramic binder, hollow ceramic microspheres, defoamer and rheology modifier while stirring at 300 r / min. Stir for 30 min, filter and package. Step 3: Apply by spraying or rolling, with a dry film thickness of 0.2-0.5 mm.

8. The method for preparing a tunnel fireproof, waterproof, and antibacterial coating according to claim 1, characterized in that: The tunnel fireproof, waterproof and antibacterial coating is composed of a base coat, a middle coat and a top coat. The composite coating thickness is 12-12.5mm and the fire resistance limit is more than 2.5h.