Anticorrosion and fireproof integrated coating and preparation method thereof

Abstract

The application discloses an anti-corrosion and fireproof integrated coating and a preparation method thereof, and relates to the technical field of building coatings.The anti-corrosion and fireproof integrated coating comprises a nano-silicon coating on the surface of a concrete base layer;an encapsulating layer, a sealing coating layer, a reactive active primer layer and a polyurea topcoat layer are sequentially arranged on the surface of the nano-silicon coating away from the concrete base layer; and the nano-silicon coating is made of the following raw materials in parts by weight: nano-silicon sol 70-90 parts, silane coupling agent 1-2 parts, deionized water 15-20 parts and dispersing agent 0.1-0.5 parts.In the nano-silicon coating, the silane coupling agent and the nano-silicon sol are added to form a dense inorganic-organic hybrid interface layer, so that the adhesion of the coating to the concrete base layer is greater than or equal to 5 MPa, and the water absorption rate is less than or equal to 0.5%, which is more than 50% higher than the adhesion of a traditional epoxy primer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building coating, in particular to a corrosion and fireproof integrated coating and a preparation method thereof. BACKGROUND

[0002] Traditional building corrosion and fireproof coatings mostly adopt single or double layer structures (such as primer + topcoat), which have the following technical defects: peeling is prone to occur between the concrete base layer and the coating due to the difference in thermal expansion coefficient, resulting in corrosion failure. The porosity of conventional sealing layer fillers (such as talc, calcium carbonate) is relatively high, which cannot effectively block the penetration of water vapor and corrosive media, and the salt spray test life is generally less than 800 hours; in the multi-layer coating process, the temperature and humidity control is not accurate, which is prone to produce bubbles, sagging and other defects, affecting the denseness of the coating. SUMMARY

[0003] In view of the problems existing in the existing corrosion and fireproof integrated coating and the preparation method thereof, the present application is proposed.

[0004] Therefore, the problem to be solved by the present application is that the interlayer adhesion of the coating is insufficient and the durability is poor.

[0005] To solve the above technical problems, the present application provides the following technical solutions:

[0006] In a first aspect, the present application provides a corrosion and fireproof integrated coating, comprising a concrete base layer, and further comprising a nanosilicon coating layer on the surface of the concrete base layer;

[0007] A sealing layer, a sealing coating layer, a reactive active primer layer and a polyurea topcoat layer are sequentially arranged on the surface of the nanosilicon coating layer away from the concrete base layer;

[0008] The nanosilicon coating layer is made of the following raw materials by weight:

[0009] Nanosilicon sol: 70-90 parts; silane coupling agent: 1-2 parts; deionized water: 15-20 parts; dispersing agent: 0.1-0.5 parts.

[0010] As a preferred scheme of the corrosion and fireproof integrated coating of the present application, the sealing layer is made of the following raw materials by weight:

[0011] Benpropolymer: 55-90 parts; calcium carbonate: 30-40 parts; titanium white: 2-5 parts; talc: 10-15 parts; nanosilica: 5-10 parts; leveling agent: 0.7 parts; wetting agent: 0.8 parts; film-forming aid: 6 parts; deionized water: 30 parts; thickening agent: 1 part.

[0012] As a preferred scheme of the fireproof and anticorrosive integrated coating, the closed paint layer is prepared from the following raw materials by weight:

[0013] Polyurethane: 35 parts; water: 55-60 parts; pigment: 9 parts; film forming aid: 8 parts; thickening agent: 0.7 parts; bactericide: 0.3 parts; PH regulator: 0.1 parts; defoaming agent: 0.2 parts; bridging agent: 1 part.

[0014] As a preferred scheme of the fireproof and anticorrosive integrated coating, the reaction type active primer layer is prepared from the following raw materials by weight:

[0015] Polyaspartic ester resin: 50 parts; water: 30 parts; propylene glycol methyl ether: 10 parts; active diluent: 10 parts; curing agent: 20 parts; leveling agent: 1 part.

[0016] As a preferred scheme of the fireproof and anticorrosive integrated coating, the polyurea topcoat layer is prepared from the following raw materials by weight:

[0017] Polyaspartic ester resin: 50-70 parts; aliphatic isocyanate: 30-40 parts; active diluent: 20-30 parts; ultraviolet absorbing aid: 0.5-5 parts; film forming aid: 10 parts; silicone aid: 5 parts; graphene nanosheet: 0.1-0.5 parts.

[0018] As a preferred scheme of the fireproof and anticorrosive integrated coating, the preparation method of the closed layer comprises,

[0019] The styrene-acrylic emulsion, leveling agent, wetting agent, film forming aid, and deionized water are mixed and stirred at 80°C for 30-45min, and the stirring speed is 250-300r / min;

[0020] The calcium carbonate, titanium dioxide, talc, and nano-silicon dioxide are added in stages, and the stirring speed is adjusted to 500-600r / min;

[0021] The thickening agent is added and continues to be stirred for 10-15min, the stirring temperature is raised to 90°C, the viscosity reaches 80-90KU / 25°C, and the stirring is stopped;

[0022] The closed layer is obtained.

[0023] As a preferred scheme of the fireproof and anticorrosive integrated coating, the preparation method of the closed paint layer comprises,

[0024] The polyurethane, water, pigment, film forming aid, thickening agent, bactericide, PH regulator, defoaming agent, bridging agent are stirred at 40-50 DEG C using a high-speed disperser, the stirring speed is 1000-1200 r / min, the stirring time is 20-40 min, the viscosity reaches 150+ / -20 KU / 25 DEG C, and a closed paint dispersion liquid with a fineness of less than 50 mu m is obtained;

[0025] A closed paint layer is obtained.

[0026] As a preferred scheme of the fireproof and anticorrosive integrated coating, the preparation method of the reactive primer layer comprises,

[0027] The polyaspartic ester resin, water, propylene glycol methyl ether, reactive diluent, curing agent, leveling agent are dispersed at 40-50 DEG C with a stirring speed of 800-1000 r / min for 30-45 min, the thickening agent is added and stirred for 10-15 min, and the viscosity reaches 5-10 Ku, and the stirring is stopped.

[0028] A reactive primer layer is obtained.

[0029] As a preferred scheme of the fireproof and anticorrosive integrated coating, the preparation method of the polyurea topcoat layer comprises,

[0030] The reactive diluent is added to a high-speed disperser, the graphene nanosheet is slowly added, and the high-speed disperser is started at the same time, the stirring speed is set to 1000-2000 r / min, and the dispersion is continued for 30-60 min to form a pre-dispersed mixture;

[0031] The pre-dispersed mixture is transferred to the container of a vacuum stirrer, and then the polyaspartic ester resin is added, and the stirring speed is set to 300-500 r / min.

[0032] During the stirring process, the ultraviolet absorption aid, the film forming aid and the silicone aid are slowly added, and the stirring time is set to 10-15 min.

[0033] The aliphatic isocyanate is added, the stirring speed is set to 800-1200 r / min, and the stirring is continued for 10-15 min.

[0034] The thickening agent is added and stirred for 10-15 min, and the stirring is stopped when the viscosity reaches 70-90 KU / 25 DEG C.

[0035] A polyurea topcoat layer is obtained.

[0036] In a second aspect, the embodiment of the present application also provides a preparation method of the fireproof and anticorrosive integrated coating, which comprises the fireproof and anticorrosive integrated coating, and further comprises the following steps,

[0037] cleaning the surface of the concrete base layer away from the wall body:

[0038] coating a layer of nano-silicon coating on the surface of the concrete base layer;

[0039] setting a sealing layer on the surface of the nano-silicon coating: using the latex paint of the sealing layer to coat a layer on the surface of the nano-silicon coating by a coating roller, and the rotating speed of the coating roller is controlled at 20-30 N / MIN;

[0040] setting a sealing coating layer on the surface of the sealing layer: using a coating roller to coat on the surface of the sealing layer, and the rotating speed of the coating roller is 20-25 N / MIN;

[0041] setting a reactive active primer layer on the surface of the sealing coating layer: using the reactive active primer layer to coat a layer on the surface of the sealing coating layer by a coating roller, and the rotating speed of the coating roller is controlled at 20-30 N / MIN;

[0042] setting a polyurea topcoat layer on the surface of the reactive active primer layer: using the polyurea topcoat layer to coat a layer on the surface of the reactive active primer layer by a coating roller, and the rotating speed of the coating roller is controlled at 20-30 N / MIN;

[0043] after the coating is completed, the coating is reacted for 16-24 hours under the condition that the temperature is 70-85 DEG C and the humidity is 70-85 RH%, and then reacted for 12-18 hours under the condition that the temperature is 30-35 DEG C and the humidity is 70-85 RH%, so as to form an integrated coating.

[0044] The present application has the following beneficial effects:

[0045] In the nano-silicon coating, the silane coupling agent and nano-silica sol are added to form a dense inorganic-organic hybrid interface layer, so that the adhesion of the coating to the concrete base layer is greater than or equal to 5 MPa, and the water absorption rate is less than or equal to 0.5%, which is more than 50% higher than the adhesion of the traditional epoxy primer.

[0046] In the sealing layer, nano-silicon dioxide is introduced and a staged temperature control stirring process (80 DEG C premixing + 90 DEG C thickening) is used, which prolongs the service life of the sealing layer by 50% compared with the conventional sealing layer (without nano-silicon dioxide), and the nano-silicon dioxide and the styrene-acrylic emulsion form an interpenetrating network structure, the porosity of the sealing layer is reduced by more than 50%, and the sealing layer is prepared by low-speed premixing + high-speed filler dispersion to avoid agglomeration of the nano-silicon dioxide and ensure that the surface roughness (Ra) of the coating is less than or equal to 0.3 microns.

[0047] In the polyurea topcoat layer, the added graphene nanosheet can synergistically act with the ultraviolet absorber, so that the tensile strength of the topcoat is greater than or equal to 25 MPa, the gloss retention rate is greater than or equal to 90% after 2000 hours of ultraviolet aging, and the thermal conductivity of the graphene enables the heat to quickly spread in case of fire, and the fire resistance limit is increased to 1.5 hours. Detailed Implementation

[0048] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, a detailed description is provided below in conjunction with specific embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0049] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0050] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0051] In a first aspect, embodiments of this application provide an integrated anti-corrosion and fireproof coating, including a concrete substrate.

[0052] It also includes a nano-silicon coating on the surface of the concrete substrate;

[0053] A sealing layer, a sealing coating layer, a reactive primer layer, and a polyurea topcoat layer are sequentially disposed on the surface of the nano-silicon coating away from the concrete substrate.

[0054] The nano-silicon coating is made from the following raw materials in parts by weight:

[0055] Nano silica sol: 70-90 parts; silane coupling agent: 1-2 parts; deionized water: 15-20 parts; dispersant: 0.1-0.5 parts; in this field, the dispersant is either a polycarboxylate or ammonium polyacrylate.

[0056] The synergistic effect of the silane coupling agent and the nano-silica sol not only forms a physical filler but also generates stable Si-O-Ca bonds through the chemical bonding of silanol groups with calcium hydroxide in the concrete. Adhesion test values ​​increased from 2.5 MPa for traditional coatings to ≥5 MPa, and the interface peeling mode changed from "coating-substrate peeling" to "concrete matrix failure," proving that the bonding strength exceeds the strength of the concrete itself. The micro-nano hierarchical structure of the nano-silica coating can absorb freeze-thaw stress, showing no cracking after 50 freeze-thaw cycles (-20℃ to 20℃), while traditional epoxy primers show cracks after only 20 cycles—an effect not mentioned in existing technologies.

[0057] The sealing layer is made from the following parts by weight of raw materials:

[0058] Styrene-acrylic emulsion: 55-90 parts; calcium carbonate: 30-40 parts; titanium dioxide: 2-5 parts; talc: 10-15 parts; nano silica: 5-10 parts; leveling agent: 0.7 parts; wetting agent: 0.8 parts; film-forming aid: 6 parts; deionized water: 30 parts; thickener: 1 part; the leveling agent is an organosilicon or acrylate leveling agent; the wetting agent is an acetylenide glycol or nonionic surfactant; the thickener is a hydrophobically modified ethylene oxide polyurethane; the film-forming aid is at least one of dodecyl alcohol ester, propylene glycol phenyl ether, or dipropylene glycol methyl ether.

[0059] The nano-silica does not simply fill the pores, but forms a three-dimensional interpenetrating network with the carboxyl groups (-COOH) of the styrene-acrylic emulsion through hydrogen bonds. Therefore, as shown by mercury porosimetry, the porosity is reduced from 15% in conventional closed layers to <5%, and the pore size distribution is concentrated (10-50 nm).

[0060] The sealing coating layer is made from the following raw materials in parts by weight:

[0061] Polyurethane: 35 parts; Water: 55-60 parts; Pigment: 9 parts; Film-forming aid: 8 parts; Thickener: 0.7 parts; Bactericide: 0.3 parts; pH adjuster: 0.1 parts; Defoamer: 0.2 parts; Crosslinking agent: 1 part; The defoamer is mineral oil.

[0062] The reactive primer layer is made from the following raw materials in the indicated weight fractions:

[0063] Polyaspartic acid ester resin: 50 parts; water: 30 parts; propylene glycol methyl ether: 10 parts; reactive diluent: 10 parts; curing agent: 20 parts; leveling agent: 1 part; the curing agent is an aliphatic isocyanate.

[0064] The polyurea topcoat layer is made from the following raw materials in parts by weight:

[0065] Polyaspartic acid ester resin: 50-70 parts; Aliphatic isocyanate: 30-40 parts; Reactive diluent: 20-30 parts; Ultraviolet absorption aid: 0.5-5 parts; Film-forming aid: 10 parts; Silicone aid: 5 parts; Graphene nanosheets: 0.1-0.5 parts.

[0066] In this process, graphene nanosheets form a continuous thermally conductive network in the polyurea topcoat, allowing heat to diffuse rapidly along the surface layer during a fire, thus slowing down the temperature rise of the substrate. Simultaneously, the graphene sheets block oxygen diffusion and synergistically enhance weather resistance with ultraviolet absorbers (e.g., benzotriazoles used in this embodiment). The added graphene nanosheets in the polyurea topcoat layer work synergistically with the ultraviolet absorbers, resulting in a tensile strength ≥25MPa and a gloss retention rate ≥90% after 2000 hours of ultraviolet aging. Furthermore, the thermal conductivity of graphene allows for rapid heat dissipation during a fire, increasing the fire resistance limit to 1.5 hours. Example 1

[0067] The nano-silicon coating is made from the following raw materials in parts by weight: nano-silica sol: 70 parts; silane coupling agent: 1 part; deionized water: 15 parts; dispersant: 0.1 parts, the dispersant being a polycarboxylate.

[0068] The sealing layer is made from the following raw materials in parts by weight: styrene-acrylic emulsion: 55 parts; calcium carbonate: 30 parts; titanium dioxide: 2 parts; talc: 10 parts; nano silica: 5 parts; leveling agent: 0.7 parts; wetting agent: 0.8 parts; film-forming aid: 6 parts; deionized water: 30 parts; thickener: 1 part. The leveling agent is an organosilicon; the wetting agent is an acetylenic diol; the thickener is a hydrophobically modified ethylene oxide polyurethane; and the film-forming aid is a dodecyl alcohol ester.

[0069] The sealed coating layer is made from the following raw materials in parts by weight: polyurethane: 35 parts; water: 55-60 parts; pigment: 9 parts; film-forming aid: 8 parts; thickener: 0.7 parts; bactericide: 0.3 parts; pH adjuster: 0.1 parts; defoamer: 0.2 parts; crosslinking agent: 1 part; the bactericide is benzisothiazolinone; the defoamer is mineral oil; the crosslinking agent is γ-glycidoxypropyltrimethoxysilane.

[0070] The reactive primer layer is made from the following raw materials in the following weight fractions: polyaspartic ester resin: 50 parts; water: 30 parts; propylene glycol methyl ether: 10 parts; reactive diluent: 10 parts; curing agent: 20 parts; leveling agent: 1 part; the curing agent is aliphatic isocyanate; the reactive diluent is allyl glycidyl ether.

[0071] The polyurea topcoat is made from the following raw materials in parts by weight: polyaspartic acid ester resin: 50 parts; aliphatic isocyanate: 30 parts; reactive diluent: 20 parts; ultraviolet absorption aid: 0.5 parts; film-forming aid: 10 parts; silicone aid: 5 parts; graphene nanosheets: 0.1 parts. Example 2

[0072] The nano-silica coating is made from the following raw materials in parts by weight: nano-silica sol: 80 parts; silane coupling agent: 1 part; deionized water: 18 parts; dispersant: 0.3 parts, the dispersant being ammonium polyacrylate.

[0073] The sealing layer is made from the following raw materials in parts by weight: styrene-acrylic emulsion: 70 parts; calcium carbonate: 35 parts; titanium dioxide: 4 parts; talc: 13 parts; nano silica: 7 parts; leveling agent: 0.7 parts; wetting agent: 0.8 parts; film-forming aid: 6 parts; deionized water: 30 parts; thickener: 1 part. The leveling agent is an acrylic leveling agent.

[0074] The sealed coating layer is made from the following raw materials in parts by weight: polyurethane: 35 parts; water: 58 parts; pigment: 9 parts; film-forming aid: 8 parts; thickener: 0.7 parts; bactericide: 0.3 parts; pH adjuster: 0.1 parts; defoamer: 0.2 parts; crosslinking agent: 1 part.

[0075] The reactive primer layer is made from the following raw materials in the following weight fractions: polyaspartic ester resin: 50 parts; water: 30 parts; propylene glycol methyl ether: 10 parts; reactive diluent: 10 parts; curing agent: 20 parts; leveling agent: 1 part.

[0076] The polyurea topcoat layer is made from the following raw materials in parts by weight: polyaspartic acid ester resin: 60 parts; aliphatic isocyanate: 35 parts; reactive diluent: 25 parts; ultraviolet absorption aid: 3 parts; film-forming aid: 10 parts; silicone aid: 5 parts; graphene nanosheets: 0.1-0.5 parts.

[0077] In this embodiment, the unspecified components are the same as in Example 1. Example 3

[0078] The nano-silicon coating is made from the following raw materials in parts by weight: nano-silica sol: 90 parts; silane coupling agent: 2 parts; deionized water: 20 parts; dispersant: 0.5 parts.

[0079] The sealing layer is made from the following raw materials in parts by weight: styrene-acrylic emulsion: 90 parts; calcium carbonate: 40 parts; titanium dioxide: 5 parts; talc: 15 parts; nano silica: 10 parts; leveling agent: 0.7 parts; wetting agent: 0.8 parts; film-forming aid: 6 parts; deionized water: 30 parts; thickener: 1 part. The wetting agent is a nonionic surfactant; the film-forming aid is dipropylene glycol methyl ether.

[0080] The sealed coating layer is made from the following raw materials in parts by weight: polyurethane: 35 parts; water: 60 parts; pigment: 9 parts; film-forming aid: 8 parts; thickener: 0.7 parts; bactericide: 0.3 parts; pH adjuster: 0.1 parts; defoamer: 0.2 parts; crosslinking agent: 1 part.

[0081] The reactive primer layer is made from the following raw materials in the following weight fractions: polyaspartic ester resin: 50 parts; water: 30 parts; propylene glycol methyl ether: 10 parts; reactive diluent: 10 parts; curing agent: 20 parts; leveling agent: 1 part.

[0082] The polyurea topcoat layer is made from the following raw materials in parts by weight: polyaspartic acid ester resin: 70 parts; aliphatic isocyanate: 40 parts; reactive diluent: 30 parts; ultraviolet absorption aid: 5 parts; film-forming aid: 10 parts; silicone aid: 5 parts; graphene nanosheets: 0.5 parts.

[0083] In this embodiment, the unspecified components are the same as in Example 1.

[0084] Comparative Example 1: The nano-silicon coating was removed, and a traditional epoxy primer was used. The traditional epoxy primer consisted of 50 parts epoxy resin, 10 parts curing agent, and 40 parts solvent.

[0085] Comparative Example 2: The nano-silicon coating was retained, but the silane coupling agent was removed.

[0086] Comparative Example 3: Nano-silica was removed from the sealing layer using only talc and calcium carbonate.

[0087] Comparative Example 4: Graphene was removed from the polyurea topcoat, leaving only the ultraviolet absorber.

[0088] The experimental results are shown in Table 1. In Table 1, CE1 represents Comparative Example 1, CE2 represents Comparative Example 2, CE3 represents Comparative Example 3, and CE4 represents Comparative Example 4.

[0089] Table 1: Performance Test Table for Different Components

[0090]

[0091] It is important to know that the adhesion test method is GB / T 5210-2006. A special adhesive is used to bond the test column to the coating surface, and the tensile strength (unit: MPa) is measured by a tensile testing machine. The adhesion between the coating and the substrate or between coatings is determined.

[0092] The water absorption rate is tested according to ASTM D570-2022, which involves immersing the sample in distilled water at 23°C for 24 hours (or a specific time), calculating the percentage change in mass, and determining the water absorption rate of the material under immersion or high humidity conditions.

[0093] The salt spray resistance test method is ASTM B117-2023. The sample is placed in a 5% NaCl salt spray chamber, and corrosion, blistering, and peeling are observed periodically to evaluate the corrosion resistance of the coating in the salt spray environment.

[0094] The UV aging gloss retention rate test method is to use QUV-A 2000h-2021 cycle to conduct UV irradiation (60℃) and condensation, for a total duration of 2000 hours, to simulate the accelerated aging test of the coating under UV (UVA-340 lamp) and condensation environment.

[0095] The test method for fire resistance limit is GB / T 9978.1-2019. The sample is placed under a standard fire source, and the time it takes for it to lose its integrity and heat insulation is recorded to determine the fire resistance limit of the coating.

[0096] The surface roughness test method is GB / T 3505-2020, which uses a stylus profilometer to measure the surface profile of the coating and calculates the arithmetic mean deviation (Ra).

[0097] The freeze-thaw cycle test method is ASTM D6944-2020. The sample is immersed and then repeatedly frozen and thawed 50 times. Cracks or peeling are observed to evaluate the crack resistance of the coating under freeze-thaw cycles (-20℃~20℃).

[0098] As can be seen from the table above, the adhesion of Example 2 is 5.2 MPa, which is much higher than that of CE1 (2.1 MPa) and CE2 (3.0 MPa). This is because the silane coupling agent in the nano-silicon coating forms chemical bonds (Si-O-Ca bonds) with the concrete, significantly improving the interfacial bonding strength.

[0099] Example 2 has a water absorption rate of 0.3%, which is only 1 / 6 of the 1.8% water absorption rate of CE1, demonstrating a significant advantage in impermeability. This is due to the hydrophobic modification of the nano-silica sol and the pore-filling effect of the nano-silica in the sealing layer. Although the water absorption rate of CE4 is the same as that of Example 2, its other properties (such as salt spray resistance and fire resistance limit) are still weaker than those of Example 2.

[0100] Example 2 exhibits a salt spray resistance time of 1500 hours, which is the best among the comparative examples and 2.5 times that of CE1. This is due to the effective blocking of chloride ion penetration by the three-dimensional interpenetrating network structure (nano-silica + styrene-acrylic emulsion) of the sealing layer. CE4's salt spray resistance time of 1450 hours is close to that of Example 2, but its fire resistance limit (1.0h) is lower, indicating that its formulation has shortcomings.

[0101] Example 2 exhibited a UV aging gloss retention rate of 90%, significantly higher than CE1 (40%) and CE4 (65%). This is due to the synergistic protection of the graphene thermally conductive network and UV absorbers in the polyurea topcoat. Although CE2 achieved a high gloss retention rate of 85% and CE3 88%, their insufficient salt spray resistance and adhesion indicate that their formulations prioritize a single performance characteristic.

[0102] The fire resistance limit of Example 2 is 1.5 hours, which is much higher than that of CE1 (0.5 hours) and CE4 (1.0 hours). This is because the thermal conductivity and diffusion of graphene, combined with the high cross-linking density of the polyurea topcoat, slows down the spread of fire. Although the fire resistance limits of CE2 and CE3 are the same as those of Example 2, their other properties (such as water absorption and surface roughness) are weaker.

[0103] The surface roughness of Example 2 is Ra=0.3μm, and the coating surface is smoother, which is better than 1.2μm of CE1 and 0.7μm of CE3. This is due to the optimized selection of a staged temperature-controlled stirring process and a leveling agent.

[0104] Example 2: No cracks were observed after 50 freeze-thaw cycles, while CE1 cracked and CE2 developed microcracks. This is because the micro-nano structure of the nano-silicon coating absorbs freeze-thaw stress, and the silane coupling agent enhances the interfacial toughness. Example 4

[0105] This embodiment also provides a method for preparing the sealing layer, which includes,

[0106] Styrene-acrylic emulsion, leveling agent, wetting agent, film-forming aid, and deionized water were mixed and stirred at 80°C for 30 minutes at a stirring speed of 250 r / min.

[0107] Then add calcium carbonate, titanium dioxide, talc, and nano silica in stages, and adjust the stirring speed to 500 r / min.

[0108] Add the thickener and continue stirring for 10 minutes. When the stirring temperature rises to 90°C and the viscosity reaches 80KU / 25°C, stop stirring.

[0109] Obtain a closed layer.

[0110] At a high temperature of 80℃, the dynamic bond recombination of nano-silica and styrene-acrylic emulsion can repair microcracks (SEM observation confirmed that self-healing is possible when the crack width is ≤5μm). During the 80℃ premixing stage, the molecular chains of styrene-acrylic emulsion are fully extended, coating the filler; after heating to 90℃, the thickener and styrene-acrylic emulsion form a "core-shell" structure, with precise viscosity control (80-90KU), and the coating penetration depth reaches 200μm on the concrete surface, far exceeding the 50μm of conventional processes. The introduction of nano-silica and a staged temperature-controlled stirring process (80℃ premixing + 90℃ thickening) extends the lifespan of the conventional sealing layer (without nano-silica) by 50%. During the preparation of the sealing layer, low-speed premixing + high-speed filler dispersion is used to avoid nano-silica agglomeration and ensure that the surface roughness (Ra) of the coating is ≤0.3μm. Example 5

[0111] This embodiment also provides a method for preparing a sealed coating layer, which includes:

[0112] Polyurethane, water, pigment, film-forming aid, thickener, bactericide, pH adjuster, defoamer, and crosslinking agent are mixed in a high-speed disperser at 40-50°C with a stirring speed of 1000 r / min for 20 min until the viscosity reaches 150 KU / 25°C, resulting in a uniform closed coating dispersion with a fineness of less than 50 μm.

[0113] Obtain a sealed coating layer. Example 6

[0114] This embodiment also provides a method for preparing a reactive primer layer, which includes,

[0115] Polyaspartic acid ester resin, water, propylene glycol methyl ether, reactive diluent, curing agent, and leveling agent were dispersed at 40°C and a stirring speed of 800 r / min for 30 min. Thickener was added and stirring was continued for 10 min until the viscosity reached 5 kU. Stirring was then stopped.

[0116] A reactive primer layer is obtained. Example 7

[0117] This embodiment also provides a method for preparing a polyurea topcoat layer, which includes,

[0118] Add the reactive diluent to the high-speed disperser, slowly add the graphene nanosheets, and start the high-speed disperser at the same time. Set the stirring speed to 1500 r / min and continue dispersing for 45 min to form a pre-dispersed mixture.

[0119] Transfer the pre-dispersed mixture to the container of a vacuum mixer, then add the polyaspartic acid ester resin, and set the stirring speed to 400 r / min;

[0120] During the stirring process, the UV absorption aid, film-forming aid and silicone aid are slowly added, and the stirring time is set to 15 minutes.

[0121] Add aliphatic isocyanate, set the stirring speed to 1000 r / min, and stir for 15 min;

[0122] Add thickener and continue stirring for 103 minutes. Stop stirring when the viscosity reaches 80 KU / 25℃.

[0123] Obtain a polyurea topcoat layer.

[0124] In this process, graphene nanosheets are pre-dispersed in an active diluent (such as glycidyl ether used in this embodiment). The polar groups of the active diluent adsorb the layers of graphene nanosheets, thus avoiding agglomeration (transmission electron microscopy shows that the interlayer spacing is stable at 0.8-1.2 nm). Example 8

[0125] This embodiment also provides a method for preparing an integrated anti-corrosion and fireproof coating, including the following steps:

[0126] Clean the concrete substrate surfaces away from the wall:

[0127] Apply a nano-silicon coating to the surface of the concrete substrate;

[0128] A sealing layer is set on the surface of the nano-silicon coating: a layer of sealing layer latex paint is applied to the surface of the nano-silicon coating by a coating roller, and the rotation speed of the coating roller is controlled at 20N / MIN.

[0129] A sealing coating layer is applied to the surface of the sealing layer using a coating roller at a speed of 20 N / min.

[0130] A reactive primer layer is applied to the surface of the sealed coating layer: a reactive primer layer is applied to the surface of the sealed coating layer by a coating roller, and the rotation speed of the coating roller is controlled at 20N / MIN.

[0131] A polyurea topcoat layer is applied to the surface of the reactive primer layer: a layer of polyurea topcoat layer is applied to the surface of the reactive primer layer by a coating roller, and the rotation speed of the coating roller is controlled at 20 N / min.

[0132] After the coating is applied, the coating is subjected to a reaction at 70°C and 70% RH for 16 hours. It should be noted that under these conditions, the rate of water evaporation and the rate of polycondensation reaction of the nano-silicon coating reach equilibrium, thus preventing the formation of microcracks. Then, the reaction is carried out at 30°C and 70% RH for 12 hours to form an integrated coating.

[0133] At a coating speed of 20 N / min, the coating of the sealing layer (viscosity 80-90 KU) achieves 100% filling of the pores in the nano-silicon coating.

[0134] Compared to some existing preparation methods, in this embodiment: when the coating speed is >30 N / min, the filler in the sealing layer settles due to excessive shearing, and the porosity rebounds to 10%; when the coating speed is <15 N / min, the coating thickness is uneven (fluctuation ±10 μm).

[0135] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A fire and corrosion resistant integrated coating comprising a concrete base layer, characterised in that: A nano-silicon coating is further included on the surface of the concrete base layer; A sealing layer, a closed paint layer, a reactive active primer layer, and a polyurea topcoat layer are sequentially arranged on the surface of the nano-silicon coating away from the concrete base layer; The nano-silicon coating is made of the following raw materials by weight fraction: Nano-silicon sol: 70-90 parts; silane coupling agent: 1-2 parts; deionized water: 15-20 parts; Dispersing agent: 0.1-0.5 parts; The polyurea topcoat layer is made of the following raw materials by weight fraction: Polyaspartic ester resin: 50-70 parts; aliphatic isocyanate: 30-40 parts; active diluent: 20-30 parts; ultraviolet absorbing aid: 0.5-5 parts; Film forming aid: 10 parts; Silicone aid: 5 parts; graphene nanosheet: 0.1-0.5 parts; The preparation method of the sealing layer comprises: The styrene-acrylic emulsion, leveling agent, wetting agent, film forming aid, and deionized water are mixed and stirred at 80℃ for 30-45min, with a stirring speed of 250-300r / min; Then, calcium carbonate, titanium white, talc, and nano-silicon dioxide are added in stages, and the stirring speed is adjusted to 500-600r / min; Thickening agent is added and continues to stir for 10-15min, the stirring temperature rises to 90℃, the viscosity reaches 80-90KU / 25℃, and the stirring is stopped; The sealing layer is obtained.

2. The fireproofing and corrosion protective integrated coating of claim 1, wherein: The sealing layer is made of the following raw materials by weight fraction: Styrene-acrylic emulsion: 55-90 parts; calcium carbonate: 30-40 parts; titanium white: 2-5 parts; talc: 10-15 parts; nano-silicon dioxide: 5-10 parts; Leveling agent: 0.7 parts; wetting agent: 0.8 parts; film forming aid: 6 parts; deionized water: 30 parts; thickening agent: 1 part.

3. The fireproofing and corrosion protective integrated coating of claim 2, wherein: The closed paint layer is made of the following raw materials by weight fraction: Polyurethane: 35 parts; Water: 55-60 parts; Pigment: 9 parts; film forming aid: 8 parts; thickening agent: 0.7 parts; fungicide: 0.3 parts; PH regulator: 0.1 parts; Defoaming agent: 0.2 parts; Bridging agent: 1 part.

4. The fireproofing and corrosion protective integrated coating of claim 3, wherein: The reactive active primer layer is made of the following raw materials by weight fraction: Polyaspartic ester resin: 50 parts; Water: 30 parts; propylene glycol methyl ether: 10 parts; active diluent: 10 parts; curing agent: 20 parts; leveling agent: 1 part.

5. The fireproofing and corrosion protective integrated coating of claim 4, wherein: The preparation method of the closed paint layer comprises, The polyurethane, water, pigment, film forming aid, thickening agent, fungicide, PH regulator, defoaming agent, and bridging agent are stirred at 40-50℃ using a high-speed dispersing machine, with a stirring speed of 1000-1200r / min, for 20-40min, and the viscosity reaches 150±20KU / 25℃, to obtain a closed paint dispersion liquid with a fineness of less than 50μm and uniformity; The closed paint layer is obtained.

6. The fireproofing and corrosion protective integrated coating of claim 5, wherein: The preparation method of the reactive active primer layer comprises, The polyaspartic ester resin, water, propylene glycol methyl ether, active diluent, curing agent, and leveling agent are dispersed at 40-50℃, with a stirring speed of 800-1000r / min, for 30-45min, the thickening agent is added and continues to stir for 10-15min, and the viscosity reaches 5-10Ku, and the stirring is stopped; A reactive primer layer is obtained.

7. The fireproofing and corrosion protective integrated coating of claim 6, wherein: The preparation method of the polyurea topcoat layer comprises, The active diluent is added into a high-speed dispersion machine, the graphene nanosheet is slowly added, the high-speed dispersion machine is started, the stirring speed is set to 1000-2000 r / min, and the pre-dispersion mixture is continuously dispersed for 30-60 min; The pre-dispersion mixture is transferred into the container of the vacuum stirrer, and then the polyaspartic ester resin is added, and the stirring speed is set to 300-500 r / min; In the process of stirring, the ultraviolet absorption aid, the film forming aid and the silicone aid are slowly added, and the stirring time is set to 10-15 min; The aliphatic isocyanate is added, the stirring speed is set to 800-1200 r / min, and the stirring is performed for 10-15 min; The thickening agent is added and the stirring is continuously performed for 10-15 min, and when the viscosity reaches 70-90 KU / 25℃, the stirring is stopped; A polyurea topcoat layer is obtained.

8. A method for the preparation of a fire-retardant and corrosion-protective integrated coating, characterized by: The method is used for preparing the fireproof and corrosion-resistant integrated coating layer as claimed in any one of claims 1-7, and the preparation method of the fireproof and corrosion-resistant integrated coating layer further comprises the following steps, The surface of the concrete base layer away from the wall body is cleaned: A nano-silicon coating layer is coated on the surface of the concrete base layer; An enclosed layer is arranged on the surface of the nano-silicon coating layer: a layer of the enclosed layer is coated on the surface of the nano-silicon coating layer by using a coating roller, and the rotating speed of the coating roller is controlled to be 20-30 N / MIN; A sealing coating layer is arranged on the surface of the enclosed layer: the sealing coating layer is coated on the surface of the enclosed layer by using a coating roller, and the rotating speed of the coating roller is 20-25 N / MIN; A reactive primer layer is arranged on the surface of the sealing coating layer: a layer of the reactive primer layer is coated on the surface of the sealing coating layer by using a coating roller, and the rotating speed of the coating roller is controlled to be 20-30 N / MIN; A polyurea topcoat layer is arranged on the surface of the reactive primer layer: a layer of the polyurea topcoat layer is coated on the surface of the reactive primer layer by using a coating roller, and the rotating speed of the coating roller is controlled to be 20-30 N / MIN; The coating layer after coating is reacted for 16-24 hours under the condition that the temperature is 70-85℃ and the humidity is 70-85 RH%, and then the coating layer is reacted for 12-18 hours under the condition that the temperature is 30-35℃ and the humidity is 70-85 RH%, so as to form an integrated coating layer.

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