Mildew-proof and moisture-proof thick coating type coating capable of being used in humid environment and construction method

Abstract

The invention provides a mildew-proof and moisture-proof thick-coating type coating capable of being used in a humid environment and a construction method of the mildew-proof and moisture-proof thick-coating type coating. Comprising the following raw materials: 5-10 parts of ash calcium, 5-15 parts of mineral powder, 10-15 parts of metakaolin, 10-15 parts of 80-120-mesh quartz sand combined powder, 5-10 parts of ground calcium carbonate combined powder, 10-15 parts of 200-mesh quartz sand, 5-15 parts of 300-mesh modified zeolite powder, 5-10 parts of white cement, 0.1-0.2 part of a water reducing agent, 1-3 parts of latex powder, 0.5-1 part of cellulose with 100,000 viscosity, 0.5-1 part of an alkali inhibitor and 0.2-0.5 part of a pH regulator. The 80-120-mesh quartz sand combined powder comprises 80-120-mesh quartz sand and 80-120-mesh modified quartz sand, and the heavy calcium carbonate combined powder comprises heavy calcium carbonate powder and modified heavy calcium carbonate powder. The coating can well inhibit the alkali efflorescence phenomenon of the wall, simplify the construction process and improve the construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of coatings, and more specifically, to a thick-film coating for mildew and moisture resistance that can be used in humid environments, and its application method. Background Technology

[0002] Current latex paint wall application methods typically include base layer treatment and top layer treatment. The base layer usually involves first leveling with putty, then applying two coats, followed by sanding to smooth the surface, and finally sanding any remaining imperfections. The top layer usually involves applying two coats of latex paint. However, putty, generally designed for easy sanding, has very low strength, requiring multiple thin coats, making the application process cumbersome and costly. Furthermore, putty has poor water resistance, easily fostering bacterial growth in humid environments. Latex paint, being an impermeable and non-breathable organic material, also provides a suitable environment for bacterial growth. Therefore, wall coatings applied using traditional paints and methods will quickly mold and peel off in humid environments.

[0003] Studies have found that the main reason for wall coating peeling is efflorescence. There are generally two types of substrates for coatings: one is direct application to a concrete wall, and the other is application using a layer of cement mortar about two centimeters thick as a substrate. Both concrete walls and cement mortar are composed of cement, sand, and gravel, all of which contain alkali. Sand and gravel, in particular, are materials with high alkali content. In a humid environment, the alkali in these materials dissolves in water. As the water evaporates, the alkali is released to the surface of the coating. When the dissolved alkali encounters carbon dioxide, it turns into salt and solidifies, increasing in volume – this process is known as efflorescence. This significant expansion damages the wall coating. This problem is particularly severe in poorly ventilated and humid environments such as basements, water conservancy projects, air-raid shelters, and tunnels, leading to more frequent maintenance and repairs.

[0004] Therefore, based on the above problems, it is imperative to develop an inorganic coating that is simple to apply, can be used in humid environments, and has anti-mildew, moisture-proof, alkali-resistant, and has high bonding strength to solve the problem of efflorescence on walls in such places. Summary of the Invention

[0005] In order to effectively suppress efflorescence on walls while simplifying the construction process and improving construction efficiency, the technical solution adopted in this invention is: a thick-coat anti-mildew and moisture-proof coating suitable for humid environments, which specifically includes the following raw materials by weight: 5-10 parts lime, 5-15 parts mineral powder, 10-15 parts metakaolin, 10-15 parts 80-120 mesh quartz sand composite powder, 5-10 parts heavy calcium carbonate composite powder, 10-15 parts 200 mesh quartz sand, 5-15 parts 300 mesh modified zeolite powder, 5-10 parts white cement, 0.1-0.2 parts water-reducing agent, 1-3 parts latex powder, 0.5-1 part cellulose with a viscosity of 100,000, 0.5-1 part alkali inhibitor, and 0.2-0.5 parts pH adjuster; Among them, the 80-120 mesh quartz sand composite powder includes 80-120 mesh quartz sand and 80-120 mesh modified quartz sand, and the heavy calcium composite powder includes heavy calcium powder and modified heavy calcium powder. The modified heavy calcium carbonate powder and the modified 80-120 mesh quartz sand were obtained by using sodium stearate as a modifier to modify the heavy calcium carbonate powder raw material and the 80-120 mesh quartz sand raw material to be hydrophobic. The 300-mesh modified zeolite powder is obtained by grinding and calcining zeolite raw materials; The total mass fractions of the following components are 100 parts: lime, mineral powder, metakaolin, 80-120 mesh quartz sand composite powder, heavy calcium carbonate composite powder, 200 mesh quartz sand, 300 mesh modified zeolite powder, and white cement.

[0006] Based on the above, in the 80-120 mesh quartz sand composite powder, the proportion of the 80-120 mesh modified quartz sand is less than or equal to 10 parts, and the remainder is the 80-120 mesh quartz sand.

[0007] Based on the above, in the aforementioned heavy calcium carbonate compound powder, the modified heavy calcium carbonate powder accounts for less than or equal to 5 parts, and the remainder is heavy calcium carbonate powder.

[0008] Based on the above, in the 80-120 mesh modified quartz sand, the sodium stearate accounts for 0.5% to 1.0% of the mass percentage of the 80-120 mesh quartz sand raw material.

[0009] Based on the above, in the modified heavy calcium carbonate powder, the sodium stearate accounts for 0.5% to 1.0% of the mass percentage of the heavy calcium carbonate powder raw material.

[0010] Specifically, the addition range of sodium stearate is limited to 0.5% to 1.0% because if the amount of sodium stearate added is too small, the hydrophobic modification will be incomplete, resulting in the coating still having a high water absorption rate and failing to effectively suppress alkali return. Conversely, if the amount of sodium stearate added is too large, it will lead to higher costs for hydrophobic modification and may also negatively impact the coating due to residual sodium stearate. Therefore, based on practical construction costs and effects, this invention limits the addition range of sodium stearate to 0.5% to 1.0%, preferably 1.0%.

[0011] Based on the above, white cement with a grade of 525 was selected.

[0012] Based on the above, the 300-mesh modified zeolite powder is obtained through the following steps: grinding the zeolite powder raw material to 300 mesh, placing the ground zeolite powder raw material in an electric furnace and heating it from room temperature, raising the temperature at a rate of 3℃ / min to 8℃ / min, raising the temperature to 110℃ to 130℃ and holding it for 10 min to 20 min, continuing to raise the temperature to 330℃ to 360℃ and holding it for 20 min to 40 min, and finally cooling it to room temperature with the furnace.

[0013] The present invention also provides a method for applying a thick-film anti-mildew and moisture-proof coating that can be used in humid environments, including adding water at a powder-to-water ratio of 1:(0.4-0.6), stirring, applying one coat to the wall first and then spraying another coat, or applying two coats directly to the wall.

[0014] The present invention also provides an application of a mildew-proof and moisture-proof thick coating that can be used in humid environments. This mildew-proof and moisture-proof thick coating can be used as a wall coating in humid environments such as basements, water conservancy projects, air-raid shelters, or tunnels.

[0015] This invention represents a significant advancement over existing technologies, offering substantial advantages. Specifically, it provides a thick-coat, mildew-proof, and moisture-proof coating suitable for humid environments, along with its application method. This is achieved by analyzing the root causes of efflorescence on walls painted with putty and latex paint. On one hand, it utilizes lime, mineral powder, and metakaolin—materials capable of geological polymerization—as inorganic binders in the coating, supplemented by white cement and modified zeolite powder for added strength. This replaces existing latex paint, ensuring the coating exhibits high strength, strong adhesion, and good water resistance, preventing large-scale peeling due to water seepage or dampness in humid environments. Furthermore, this weakly alkaline inorganic coating is less prone to bacterial growth in humid environments and inhibits bacterial development.

[0016] On the other hand, by modifying only a portion of the heavy calcium carbonate powder and a portion of the quartz sand to be hydrophobic, the permeability of the inorganic materials is changed and the moisture absorption capacity of the wall is reduced. At the same time, the defect of a significant reduction in coating bonding strength caused by a large amount of hydrophobic modification is avoided. This ensures that the coating of the present invention is permeable to water and air and will not be damaged during the process of alkali being released from the coating and turning into salt, thereby extending the durability of the coating.

[0017] Thirdly, by using porous zeolite as a raw material and calcining it, free water, crystal water, and some organic matter in the zeolite can be removed. This allows the zeolite to be stored to the maximum extent and slows down the rate at which it passes through the coating when efflorescence occurs on the wall. When the alkali not absorbed by the coating is released again, the amount of alkali is reduced, and its destructive power is also reduced. Furthermore, since this product is an alkali-activating material, the alkali generated in the base layer, after being intercepted by the modified zeolite, can also promote the geopolymerization reaction, which can improve the strength of the coating to a certain extent. This can compensate for the defect of reduced bonding strength caused by the hydrophobic modification of quartz sand and heavy calcium carbonate powder. Therefore, under the combined action of modified heavy calcium carbonate powder, modified quartz sand, modified zeolite, and other raw materials, the occurrence of large-area severe efflorescence on the wall is ultimately suppressed, extending the durability of the coating and the service life of the wall coating.

[0018] More importantly, this mildew-proof and moisture-proof thick-coat paint, through the reasonable matching of the particle size of each powder, uses 80-120 mesh quartz sand, 80-120 mesh modified quartz sand, and 300 mesh modified zeolite powder as raw materials. The relatively large particle size of each raw material, combined with a controlled powder-to-water ratio of 1:(0.4-0.6) during construction, results in a viscous paste-like consistency with high viscosity and good anti-sagging properties. Even when applied in a single spray coat to a thickness of 1.5mm-2mm, sagging does not occur on the wall. Furthermore, combined with the paint's inherent high strength and high adhesion, thick-coat application is possible. Two coats are sufficient to achieve the required wall coating thickness, simplifying the construction process and significantly improving efficiency.

[0019] Therefore, this invention addresses the principles of alkali return, peeling, and mold growth in coatings. By utilizing geological polymerization reactions and modifying some heavy calcium carbonate powder and some quartz sand for hydrophobicity, as well as modifying zeolite powder, it solves the problems that occur with coatings in humid environments while ensuring high strength after application, meeting the requirements for thick coatings. This simplifies the application process, reducing it from six steps to two, thus improving efficiency. The coating provided by this invention can be used in humid environments and offers advantages such as mold resistance, moisture resistance, alkali resistance, high bonding strength, simple application process, and high application efficiency. Attached Figure Description

[0020] Figure 1 These are wall effect images provided by the present invention, showing the anti-mildew and moisture-proof thick coating that can be used in humid environments before, after, and two years after application. Figure 1In Figure a, the wall surface shows efflorescence after latex paint application; in Figure b, the wall surface effect after application using the anti-mildew and moisture-proof thick coating provided by this invention; in Figure c, the overall wall surface effect two years after application; and in Figure d, the partial wall surface effect two years after application.

[0021] Figure 2 This is a wall effect diagram of a thick-coat anti-mildew and moisture-proof coating provided by the present invention, which can be used in humid environments, after construction in a tunnel and after the tunnel is put into use. Figure 2 Image a shows the effect after the tunnel construction is completed, and image b shows the effect of the tunnel walls after it is put into use.

[0022] Figure 3 This is an image showing the effect of hydrophobic modification of quartz sand and calcium powder in a thick-coat, mildew-proof and moisture-proof coating that can be used in humid environments, as provided by this invention.

[0023] Figure 4 This invention provides the environmental performance test results for a thick-film coating that is mildew-proof and moisture-proof and can be used in humid environments. Detailed Implementation

[0024] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0025] The main objective of this invention is to effectively suppress efflorescence on walls while ensuring good adhesion strength of the wall coating, meeting the requirements for thick coating construction, simplifying the construction process, and improving construction efficiency.

[0026] To achieve this objective, this invention is based on the principle of geological polymerization reaction. It utilizes lime, mineral powder, and metakaolin, which are capable of geological polymerization reactions, as inorganic binders in the coating, and supplements strength with white cement and modified zeolite powder, thus replacing existing latex paint and obtaining a basic coating formula. However, the water and air permeability of inorganic materials increases the possibility of moisture absorption by the wall; therefore, it is necessary to reduce the coating's water absorption rate and the rate at which alkali passes through the coating.

[0027] To address this problem, this invention reduces the water absorption rate of some inorganic materials, removes free water, crystal water, and some organic matter from zeolite, thereby storing alkali and slowing down the rate at which alkali passes through the coating. This improves the coating's ability to inhibit alkali return and enhances its bonding strength, ensuring high bonding strength after coating application.

[0028] Based on the above concept and specific implementation schemes, the present invention will be further described in detail below.

[0029] I. Basic Formulation of Coatings The specific raw materials include the following by weight: 5-10 parts lime, 5-15 parts mineral powder, 10-15 parts metakaolin, 10-15 parts 80-120 mesh quartz sand, 5-10 parts heavy calcium carbonate powder, 10-15 parts 200 mesh quartz sand, 5-15 parts zeolite powder, 5-10 parts white cement with a grade of 525, 0.1-0.2 parts water-reducing agent, 1-3 parts latex powder, 0.5-1 part cellulose with a viscosity of 100,000, 0.5-1 part alkali inhibitor, and 0.5 parts pH adjuster.

[0030] The total mass fraction of the following components is 100 parts: lime, mineral powder, metakaolin, 80-120 mesh quartz sand, heavy calcium carbonate powder, 200 mesh quartz sand, zeolite powder, and white cement. The pH adjuster is a mixture of sodium hydrogen phosphate and sodium dihydrogen phosphate in a 1:1 mass ratio; the alkali inhibitor is YJ-ky01; and the water-reducing agent is polycarboxylic acid.

[0031] In this basic formulation, the quartz sand and heavy calcium carbonate powder used as fillers not only affect the water absorption rate of the coating but also its adhesion strength. Furthermore, because zeolite has a porous structure, the zeolite raw materials will adsorb free water, crystal water, and some organic matter, which will affect the water absorption rate of the coating and its ability to inhibit alkali return.

[0032] Therefore, the calcination modification process of zeolite powder, the modification process of 80-120 mesh quartz sand and heavy calcium carbonate powder, and the proportions of modified quartz sand, modified heavy calcium carbonate powder, and modified zeolite powder are crucial to the strength of the coating and the inhibition of alkali return.

[0033] Therefore, the following studies investigate the effects of the modification processes of quartz sand and heavy calcium carbonate powder, the calcination modification process of zeolite powder, and the addition amount of each modifying material on the adhesion strength of the coating and the inhibition of alkali reversion. The specific contents are as follows: II. Modification steps for 80-120 mesh quartz sand When modifying 80-120 mesh quartz sand, the specific basic formula is as follows: 5 parts lime, 15 parts mineral powder, 15 parts metakaolin, 15 parts 80-120 mesh quartz sand, 10 parts heavy calcium carbonate powder, 15 parts 200 mesh quartz sand, 15 parts 300 mesh zeolite powder, 10 parts white cement (grade 525), 0.2 parts water-reducing agent, 1 part latex powder, 0.5 parts cellulose with a viscosity of 100,000, 0.5 parts alkali inhibitor, and 0.5 parts pH adjuster. Specifically, the pH adjuster is a 1:1 mass mixture of sodium hydrogen phosphate and sodium dihydrogen phosphate; the alkali inhibitor is YJ-ky01; and the water-reducing agent is polycarboxylic acid.

[0034] In the specific modification process, the proportions of other components remain unchanged, and only a portion of the 15 parts of 80-120 mesh quartz sand is modified. That is, the total mass of the modified 80-120 mesh quartz sand and the unmodified 80-120 mesh quartz sand is still 15 parts.

[0035] The specific steps are as follows: First, 80-120 mesh quartz sand is used as the raw material to be modified, and sodium stearate, accounting for 1% of the mass of the 80-120 mesh quartz sand, is weighed out as a modifier. Then, the weighed 80-120 mesh quartz sand and sodium stearate are added to the modification mixing pot.

[0036] The modification mixing tank is a high-speed mixing device with three stirring blades at the bottom and four guide plates at different angles on the inner wall. During modification, the stirring blades rotate at a speed of 1400 revolutions per minute. Inside the mixing tank, 80-120 mesh quartz sand and sodium stearate rotate under the influence of the stirring blades. Due to the guide plates, the materials inside the equipment collide and generate heat. After the modification equipment rotates at high speed for 3-5 minutes, the temperature inside the tank reaches 70℃, thus completing the hydrophobic modification of the 80-120 mesh quartz sand. Figure 3 As shown, the modified quartz sand can achieve a good hydrophobic effect.

[0037] III. Effect of 80-120 mesh modified quartz sand addition on coating water absorption and bond strength 3.1 Procedure for determining the water absorption rate of the coating The modified and remaining unmodified 80-120 mesh quartz sand were added to the specific formula in the aforementioned "80-120 mesh quartz sand modification step" to prepare the coating to be tested. Water was added at a powder-to-water ratio of 1:0.5, the sample was stirred evenly, and coated onto a 150×200mm glass plate. Three plates were made, and the coating thickness of each plate was 2mm.

[0038] The prepared samples were placed in a constant temperature and humidity curing chamber at 50% humidity and 25℃ for 7 days. The weight 'a' of each of the three samples was then measured. The samples were then completely immersed in water for 24 hours. After removing the samples, the surface water was wiped away with a paper towel, and the weight 'b' of the sample was quickly measured. The water absorption rate of the sample can then be calculated. To calculate the water absorption rate, first calculate the difference between weight 'b' and weight 'a', and then calculate the ratio of this difference to weight 'a'.

[0039] 3.2 Test Procedure for Determining the Adhesion Strength of Coatings in a Humid Environment The modified and remaining unmodified 80-120 mesh quartz sand were added to the specific formula in the aforementioned "80-120 mesh quartz sand modification step" to prepare the coating to be tested. Water was added at a powder-to-water ratio of 1:0.5, the sample was stirred evenly, and coated onto a 70mm×70mm normal mortar test block. Seven plates were made, and the coating thickness of each plate was 2mm.

[0040] The coated sample was placed inside a sealed container equipped with a timed water spraying device, spraying water for 3 minutes every 2 hours. This test was conducted for 7 days. Afterward, the test mortar block was placed in a dry container to air dry for 7 days. The tensile strength test was performed according to GB / T 9779 to determine the adhesion strength of the coating.

[0041] The specific water absorption rate test results and strength test results are shown in Table 1. As can be seen from Table 1, adding 80-120 mesh modified quartz sand has a significant benefit in reducing the water absorption of the coating surface.

[0042] However, during the experiment, it was found that adding too much modified 80-120 mesh quartz sand resulted in a decrease in strength. Therefore, after further testing, the amount of 80-120 mesh modified quartz sand was limited to less than or equal to 10 parts.

[0043] Table 1. Effect of modified quartz sand addition on coating water absorption and bond strength. Serial Number Modified quartz sand addition amount (parts) Water absorption rate Coating adhesion strength (MPa) 1 0 5.68% 1.0 2 3 4.82% 0.8 3 6 4.07% 0.7 4 9 3.24% 0.7 5 12 2.61% 0.6 6 15 1.98% 0.5 7 18 1.46% 0.4 8 20 1.22% 0.2 IV. Modification Steps of Heavy Calcium Carbonate Powder Based on the test results of the modification of 80-120 mesh quartz sand, the specific formula for modifying heavy calcium carbonate powder is as follows: 5 parts lime, 15 parts mineral powder, 15 parts metakaolin, 10 parts 80-120 mesh modified quartz sand, 5 parts 80-120 mesh quartz sand, 10 parts heavy calcium carbonate powder, 15 parts 200 mesh quartz sand, 15 parts 300 mesh zeolite powder, 10 parts white cement (grade 525), 0.2 parts water-reducing agent, 1 part latex powder, 0.5 parts cellulose with a viscosity of 100,000, 0.5 parts alkali inhibitor, and 0.5 parts pH adjuster. Specifically, the pH adjuster is a mixture of sodium hydrogen phosphate and sodium dihydrogen phosphate in a 1:1 mass ratio; the alkali inhibitor is YJ-ky01; and the water-reducing agent is polycarboxylic acid.

[0044] In other words, during the modification process, the proportions of other components remain unchanged; only a portion of the 10 parts of heavy calcium carbonate powder is modified. Therefore, the total mass of the modified and unmodified heavy calcium carbonate powder remains 10 parts. The specific modification steps are as follows: First, weigh out the heavy calcium carbonate powder as the raw material to be modified, and weigh out sodium stearate (1% of the mass of the heavy calcium carbonate powder) as the modifier. Then, add the weighed heavy calcium carbonate powder and sodium stearate into the modification mixing pot.

[0045] During modification, the stirring blades rotate at a speed of 1400 revolutions per minute. The heavy calcium carbonate powder and sodium stearate inside the mixing pot rotate under the influence of the stirring blades. Due to the design of the guide plates, the materials inside the equipment collide with each other, generating heat. The modification equipment rotates at high speed for 3-5 minutes, and when the temperature inside the pot reaches 70℃, the hydrophobic modification of the heavy calcium carbonate powder is complete.

[0046] V. Effect of Modified Heavy Calcium Carbonate Powder Addition on Coating Water Absorption and Coating Bond Strength The modified and remaining unmodified heavy calcium carbonate powder were added to the specific formulation in the aforementioned "heavy calcium carbonate powder modification step" to prepare the coating to be tested. Then, the water absorption rate and coating adhesion strength of the coating to be tested were determined according to the determination steps in 3.1 and 3.2 above.

[0047] The specific results are shown in Table 2. As can be seen from Table 2, adding modified heavy calcium carbonate powder has a significant benefit in reducing the water absorption of the coating surface. However, during the experiment, it was found that adding too much modified raw material resulted in a decrease in strength. When 6 parts of modified heavy calcium carbonate powder were added, the decrease in strength was quite significant.

[0048] Analysis suggests that heavy calcium carbonate powder, with its relatively fine particle size, acts as a filler and bridge in the entire formulation system. Sufficiently distributing heavy calcium carbonate powder between various materials improves the system's density, enhancing the product's bonding properties and resistance to damage, thereby increasing its resistance to powdering. Therefore, if the amount of modified heavy calcium carbonate powder added is too large, the modified powder loses its hydrophilic properties and cannot play a binding role in the subsequent hydration reaction. Thus, the amount of modified heavy calcium carbonate powder added should be controlled to below 5 parts.

[0049] Table 2. Effect of modified heavy calcium carbonate powder addition on coating water absorption and bonding strength. Serial Number Modified heavy calcium carbonate powder addition amount (parts) Water absorption rate Coating adhesion strength (MPa) 1 0 6.68% 0.9 2 3 5.77% 0.7 3 6 4.23% 0.4 4 9 3.14% 0.3 As shown above, simply modifying a portion of the 80-120 mesh quartz sand and a portion of the heavy calcium carbonate powder to be hydrophobic will result in a decrease in the coating's adhesive strength. Furthermore, hydrophobic modification alone cannot fundamentally store or slow down the rate at which alkali passes through the coating. Therefore, modification of other components is necessary to compensate for the strength reduction. This invention specifically selects zeolite powder from the raw materials for modification, which, while storing and slowing down the rate at which alkali passes through the coating, also maintains the coating's high adhesive strength. The specific modification steps are as follows.

[0050] VI. Zeolite Modification Steps Based on the test results of the modification of 80-120 mesh quartz sand and the modification of heavy calcium carbonate powder, the specific formula for modifying zeolite is as follows: 5 parts lime, 15 parts mineral powder, 15 parts metakaolin, 10 parts 80-120 mesh modified quartz sand, 5 parts 80-120 mesh quartz sand, 5 parts modified heavy calcium carbonate, 5 parts heavy calcium carbonate powder, 15 parts 200 mesh quartz sand, 15 parts 300 mesh zeolite powder, 10 parts white cement (grade 525), 0.2 parts water-reducing agent, 1 part latex powder, 0.5 parts cellulose with a viscosity of 100,000, 0.5 parts alkali inhibitor, and 0.5 parts pH adjuster. Specifically, the pH adjuster is a mixture of sodium hydrogen phosphate and sodium dihydrogen phosphate in a 1:1 mass ratio; the alkali inhibitor is YJ-ky01; and the water-reducing agent is polycarboxylic acid.

[0051] In the specific modification process, the proportions of other components remain unchanged, and only a portion of the 15 parts of zeolite powder is modified. That is, the total mass of the modified and unmodified zeolite powder remains 15 parts. The specific modification steps are as follows: The zeolite is ground to a fineness of 300 mesh, requiring a 90% passing rate through the 300-mesh sieve. The ground zeolite material is then calcined in an electric furnace, starting at room temperature and increasing the temperature by 5°C per minute. The temperature is then raised to 120°C and held for 15 minutes, followed by a further increase to 350°C and held for 30 minutes. This process ensures complete removal of free water, water of crystallization, and some organic matter from the zeolite, opening its pores. The calcined zeolite is then allowed to cool naturally to room temperature in the furnace. Finally, it is quickly transferred to a desiccator and sealed.

[0052] VII. Effect of Modified Zeolite Addition Amount on Coating Bond Strength and Alkali Return in Coating The modified zeolite powder and the remaining unmodified zeolite powder are added to the specific formula in the aforementioned "zeolite modification step" to prepare the coating to be tested.

[0053] Mortar test blocks of 40mm×160mm×160mm were made. When 20 blocks were formed, 2% sodium hydroxide of the total mortar mass was added to create an alkaline base layer. 10 mortar blocks were formed normally.

[0054] The molded mortar test blocks were coated according to the test plan, with the coating thickness controlled at approximately 2 mm. The coated blocks were placed inside a sealed container equipped with a timed water spraying device, spraying water for 3 minutes every 2 hours. This process was repeated for 7 days. Afterward, the mortar blocks were placed in a dry container to air dry for another 7 days. The pull-out strength of the coating was tested according to GB / T 9779.

[0055] Meanwhile, the degree of alkali reversion in the coating is judged based on the area occupied by the alkali. The specific degree of alkali reversion can be divided into: slight alkali reversion (less than one-tenth of the area), mild alkali reversion (less than one-fifth of the area), moderate alkali reversion (less than one-third of the area), and severe alkali reversion (nearly half of the area).

[0056] The specific test results are shown in Table 3. Table 3 shows that the coating without modified zeolite exhibits severe efflorescence when encountering alkaline walls, and its strength is also low. However, the coating with modified zeolite shows improved bonding strength and does not exhibit large-scale efflorescence when encountering alkaline walls, indicating that modified zeolite powder can improve the coating's bonding strength and inhibit efflorescence.

[0057] Meanwhile, the relationship between the amount of modified zeolite added and the adhesion strength of the coating shows that as the amount of modified zeolite added increases, the adhesion strength of the coating shows a certain upward trend. This indicates that after zeolite modification, the adsorbed free water, water of crystallization, and some organic matter in the zeolite raw material can be effectively removed. Therefore, when modifying zeolite, all parts of zeolite can be modified.

[0058] Table 3. Effects of modified zeolite on coating adhesion strength and alkali return in test blocks. Mortar block condition Modified zeolite addition amount (parts) Bond strength (MPa) Coating surface condition 5 normal mortar test blocks 0 0.8 Slight efflorescence 5 normal mortar test blocks 5 0.9 Slight efflorescence Five test blocks with added sodium hydroxide 0 0.4 Severe efflorescence Five test blocks with added sodium hydroxide 5 0.5 Moderate efflorescence Five test blocks with added sodium hydroxide 10 0.6 Slight efflorescence Five test blocks with added sodium hydroxide 15 0.7 Slight efflorescence In summary, the thick-film coating for mildew and moisture resistance provided by this invention, which can be used in humid environments, takes into account the bonding strength and alkali return of the coating. Specifically, the amount of 80-120 mesh modified quartz sand is limited to less than or equal to 10 parts, the amount of modified heavy calcium carbonate powder is limited to less than or equal to 5 parts, and all zeolites are modified.

[0059] Therefore, based on the above test results, the present invention specifically provides the following embodiments.

[0060] Example 1 This embodiment provides a thick-coat, mildew-proof and moisture-proof coating suitable for use in humid environments. By weight, it comprises: 5 parts lime, 15 parts mineral powder, 15 parts metakaolin, 10 parts 120-mesh modified quartz sand, 5 parts 120-mesh quartz sand, 5 parts modified heavy calcium carbonate powder, 5 parts heavy calcium carbonate powder, 15 parts 200-mesh quartz sand, 15 parts 300-mesh modified zeolite powder, 10 parts white cement (grade 525), 0.2 parts water-reducing agent, 1 part latex powder, 0.5 parts cellulose with a viscosity of 100,000, 0.5 parts alkali inhibitor, and 0.5 parts pH adjuster.

[0061] Among them, the pH adjuster is a mixture of sodium hydrogen phosphate and sodium dihydrogen phosphate in a mass ratio of 1:1, the alkali inhibitor is YJ-ky01, and the water reducing agent is polycarboxylic acid.

[0062] This embodiment provides a method for preparing a thick-film coating that is mildew-proof and moisture-proof and can be used in humid environments, including weighing each raw material according to the above-mentioned mass proportions, and then mixing the weighed raw materials.

[0063] This embodiment also provides a construction method for a thick-coat anti-mildew and moisture-proof coating that can be used in humid environments. Specifically, water is added to the thick-coat anti-mildew and moisture-proof coating that can be used in humid environments at a powder-to-water ratio of 1:0.4, and the mixture is stirred. Two coats are then applied directly to the wall.

[0064] This embodiment also provides an application of a mildew-proof and moisture-proof thick coating that can be used in humid environments. This mildew-proof and moisture-proof thick coating can be used as a wall coating in water conservancy projects.

[0065] Example 2 This embodiment provides a thick-coat anti-mildew and moisture-proof coating suitable for use in humid environments. By weight, it includes: 10 parts of lime, 15 parts of mineral powder, 15 parts of metakaolin, 10 parts of 80-mesh modified quartz sand, 5 parts of 80-mesh quartz sand, 5 parts of modified heavy calcium carbonate powder, 5 parts of heavy calcium carbonate powder, 15 parts of 200-mesh quartz sand, 10 parts of modified zeolite powder, 10 parts of white cement with a grade of 525, 0.2 parts of water-reducing agent, 3 parts of latex powder, 1 part of cellulose with a viscosity of 100,000, 1 part of alkali inhibitor, and 1 part of pH adjuster.

[0066] Among them, the pH adjuster is a mixture of sodium hydrogen phosphate and sodium dihydrogen phosphate in a mass ratio of 1:1, the alkali inhibitor is YJ-ky01, and the water reducing agent is polycarboxylic acid.

[0067] This embodiment provides a method for preparing a thick-film coating that is mildew-proof and moisture-proof and can be used in humid environments, including weighing each raw material according to the above-mentioned mass proportions, and then mixing the weighed raw materials.

[0068] This embodiment also provides a construction method for a thick-film coating that is mildew-proof and moisture-proof and can be used in humid environments. Specifically, water is added to the thick-film coating that is mildew-proof and moisture-proof and can be used in humid environments at a powder-to-water ratio of 1:0.5 and stirred. One coat is first applied to the wall and then another coat is sprayed directly onto it.

[0069] This embodiment also provides an application of a mildew-proof and moisture-proof thick-coat paint that can be used in humid environments. This mildew-proof and moisture-proof thick-coat paint can be used as a wall coating in tunnels.

[0070] Example 3 This embodiment provides a thick-coat, mildew-proof and moisture-proof coating suitable for use in humid environments. By weight, it comprises: 10 parts lime, 15 parts mineral powder, 15 parts metakaolin, 3 parts 120-mesh modified quartz sand, 12 parts 120-mesh quartz sand, 4 parts modified heavy calcium carbonate powder, 6 parts heavy calcium carbonate powder, 15 parts 200-mesh quartz sand, 11 parts modified zeolite powder, 9 parts white cement (grade 525), 0.1 parts water-reducing agent, 1 part latex powder, 1 part cellulose with a viscosity of 100,000, 0.5 parts alkali inhibitor, and 1 part pH adjuster.

[0071] Among them, the pH adjuster is a mixture of sodium hydrogen phosphate and sodium dihydrogen phosphate in a mass ratio of 1:1, the alkali inhibitor is YJ-ky01, and the water reducing agent is polycarboxylic acid.

[0072] This embodiment provides a method for preparing a thick-film coating that is mildew-proof and moisture-proof and can be used in humid environments, including weighing each raw material according to the above-mentioned mass proportions, and then mixing the weighed raw materials.

[0073] This embodiment also provides a construction method for a thick-film coating that is mildew-proof and moisture-proof and can be used in humid environments. Specifically, water is added to the thick-film coating that is mildew-proof and moisture-proof and can be used in humid environments at a powder-to-water ratio of 1:0.6 and stirred. One coat is first applied to the wall and then another coat is sprayed directly onto it.

[0074] This embodiment also provides an application of a mildew-proof and moisture-proof thick coating that can be used in humid environments. This mildew-proof and moisture-proof thick coating can be used as a wall coating in air-raid shelters.

[0075] Performance testing Following the measurement steps in 3.1 and 3.2 above and the criteria for judging efflorescence in Title 7, the water absorption rate, coating adhesion strength and efflorescence of the coatings provided in Example 1, Example 2 and Example 3 were measured respectively. The specific results are shown in Table 4.

[0076] Table 4 shows the coating water absorption rate, bond strength, and alkali return in each example. sample Water absorption rate Coating adhesion strength (MPa) Coating surface condition Example 1 4.30% 0.8 Slight efflorescence Example 2 4.35% 0.7 Slight efflorescence Example 3 4.36% 0.6 Slight efflorescence Unmodified base formulation 5.68% 1.0 Severe efflorescence As can be seen from Table 4, the three embodiments described above all demonstrate that the thick-film anti-mildew and moisture-proof coatings suitable for humid environments have low water absorption rates and exhibit minimal alkali return on the coating surface. Furthermore, the coatings retain high adhesive strength.

[0077] In summary, this invention addresses the principles behind coating efflorescence, peeling, and mold growth. By utilizing geological polymerization reactions and modifying a portion of the heavy calcium carbonate powder and quartz sand for hydrophobicity, as well as modifying the zeolite powder, and by rationally selecting the proportions of modified quartz sand, modified heavy calcium carbonate powder, and modified zeolite, and carefully choosing the particle size of the raw materials, this invention not only solves the problems encountered by the coating in humid environments but also ensures high strength after application, meeting the requirements for thick coatings. This simplifies the application process, reducing it from six steps to two, thus improving efficiency. The resulting coating is suitable for humid environments and offers advantages such as mold resistance, moisture resistance, alkali resistance, high bonding strength, simple application process, and high application efficiency.

[0078] Wall painting test This invention, according to Embodiment 1, utilizes a thick-coat, mildew-proof, and moisture-resistant coating suitable for humid environments for wall painting at a South-to-North Water Diversion Project pumping station. The specific construction steps include adding water to the mildew-proof and moisture-resistant thick-coat coating at a powder-to-water ratio of 1:0.4, stirring, and applying two coats to the wall. The specific construction effect is as follows... Figure 1 As shown.

[0079] from Figure 1It can be seen that the South-to-North Water Diversion Pumping Station originally used the conventional construction method of putty plus latex paint. Because the pumping station is built across the South-to-North Water Diversion River, the humidity is very high and it is in a humid environment all year round. The original walls developed problems such as mold, powdering and peeling in less than six months, causing the wall paint to keep peeling off and requiring multiple repairs to the wall surface every year.

[0080] Two years after the wall construction was carried out using the anti-mildew and moisture-proof thick coating provided by this invention, which can be used in humid environments, the walls of the South-to-North Water Diversion Pumping Station still did not show large-scale efflorescence and peeling.

[0081] This invention, in Embodiment 2, utilizes a thick-coat, mildew-proof, and moisture-resistant paint suitable for humid environments for wall painting in the Heping Road Tunnel in Xuzhou. The specific construction steps include adding water to the mildew-proof and moisture-resistant thick-coat paint at a powder-to-water ratio of 1:0.4, stirring, adding yellow pigment, and spraying it onto the wall. The specific construction effect is as follows... Figure 2 As shown. From Figure 2 It can be seen that after the tunnel walls were put into use, there was still no large-scale efflorescence or peeling of the walls.

[0082] Therefore, the anti-mildew and moisture-proof thick coating provided by the present invention has a good ability to inhibit efflorescence on walls in humid environments.

[0083] Environmental performance testing The environmental performance of the anti-mildew and moisture-proof thick-coat paint provided by this invention, which can be used in humid environments, was tested, and the results are as follows: Figure 4 As shown. From Figure 4 As can be seen, this thick-coat anti-mildew and moisture-proof coating suitable for humid environments does not contain VOCs, formaldehyde, benzene compounds, lead, soluble heavy metals, or other substances, and exhibits good anti-mildew properties. Therefore, this thick-coat anti-mildew and moisture-proof coating suitable for humid environments demonstrates excellent environmental performance and is an environmentally friendly inorganic coating.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A thick-coat, mildew-proof, and moisture-proof coating suitable for use in humid environments, characterized in that: The ingredients include the following raw materials by weight: 5-10 parts lime, 5-15 parts mineral powder, 10-15 parts metakaolin, 10-15 parts 80-120 mesh quartz sand composite powder, 5-10 parts heavy calcium carbonate composite powder, 10-15 parts 200 mesh quartz sand, 5-15 parts 300 mesh modified zeolite powder, 5-10 parts white cement, 0.1-0.2 parts water-reducing agent, 1-3 parts latex powder, 0.5-1 part cellulose with a viscosity of 100,000, 0.5-1 part alkali inhibitor, and 0.2-0.5 parts pH adjuster; Among them, the 80-120 mesh quartz sand composite powder includes 80-120 mesh quartz sand and 80-120 mesh modified quartz sand, and the heavy calcium composite powder includes heavy calcium powder and modified heavy calcium powder. The modified heavy calcium carbonate powder and the modified 80-120 mesh quartz sand are obtained by using sodium stearate as a modifier to modify the heavy calcium carbonate powder raw material and the 80-120 mesh quartz sand raw material to be hydrophobic. The 300-mesh modified zeolite powder is obtained by grinding zeolite raw materials and then calcining them. The total mass fractions of the following components are 100 parts: lime, mineral powder, metakaolin, 80-120 mesh quartz sand composite powder, heavy calcium carbonate composite powder, 200 mesh quartz sand, 300 mesh modified zeolite powder, and white cement.

2. The anti-mildew and moisture-proof thick-coat paint for use in humid environments according to claim 1, characterized in that: In the 80-120 mesh quartz sand composite powder, the proportion of the 80-120 mesh modified quartz sand is less than or equal to 10 parts, and the remainder is the 80-120 mesh quartz sand.

3. A thick-film anti-mildew and moisture-proof coating suitable for use in humid environments according to claim 1 or 2, characterized in that: In the aforementioned heavy calcium carbonate compound powder, the modified heavy calcium carbonate powder accounts for less than or equal to 5 parts, and the remainder is the original heavy calcium carbonate powder.

4. A thick-film coating for mildew and moisture resistance suitable for humid environments according to claim 3, characterized in that: In the 80-120 mesh modified quartz sand, the sodium stearate accounts for 0.5% to 1.0% of the mass percentage of the 80-120 mesh quartz sand raw material.

5. A thick-film coating for mildew and moisture resistance suitable for humid environments according to claim 1, characterized in that: In the modified heavy calcium carbonate powder, the sodium stearate accounts for 0.5% to 1.0% of the mass percentage of the heavy calcium carbonate powder raw material.

6. A thick-film coating for mildew and moisture resistance suitable for use in humid environments according to claim 1, 2, or 5, characterized in that: The white cement used is grade 525 white cement.

7. A thick-film anti-mildew and moisture-proof coating suitable for use in humid environments according to claim 1, 2, or 5, characterized in that: The 300-mesh modified zeolite powder is obtained through the following steps: grinding the zeolite powder raw material to 300 mesh, placing the ground zeolite powder raw material in an electric furnace, starting from room temperature and heating at a rate of 3℃ / min to 8℃ / min, heating to 110℃ to 130℃ and holding for 10 min to 20 min, continuing to heat to 330℃ to 360℃ and holding for 20 min to 40 min, and finally cooling to room temperature with the furnace.

8. A method for applying a thick-coat anti-mildew and moisture-proof coating for use in humid environments as described in any one of claims 1 to 7, comprising adding water at a powder-to-water ratio of 1:(0.4 to 0.6), stirring, applying one coat to the wall first and then spraying another coat, or applying two coats directly to the wall.

9. The application of a thick-film anti-mildew and moisture-proof coating as described in any one of claims 1 to 7, characterized in that, This mildew-proof and moisture-proof thick-coat paint can be used as a wall coating in damp environments such as basements, water conservancy projects, air-raid shelters, or tunnels.

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