Functional back and face water surface double-effect waterproof coating and preparation method and construction method thereof

Abstract

The application discloses a functional double-effect waterproof coating for water-facing and back-facing surfaces, and a preparation method and a construction method thereof. The coating is a two-component system composed of liquid material and powder material, and is mixed by liquid material: powder material: water=1:10:(2-2.5) during construction. The liquid material is composed of 80.0-90.0 wt% of two-component waterproof special emulsion (silicon-wax hybrid saponification type hydrophobic modified emulsion) and 10.0-20.0 wt% of an anti-efflorescence waterproof additive composition. The powder material includes white portland cement, calcined kaolin, high-whiteness heavy calcium carbonate and rutile titanium dioxide. The functional emulsion completely wraps cement particles, the additive composition inhibits alkali through the double mechanism of complexing calcium ions and sealing with pozzolanic gel, and the white powder material gives the coating film a finishing effect. The three components are synergistic, so that the coating realizes 0.8 MPa bidirectional impermeability of water-facing and back-facing surfaces, 1st grade accelerated efflorescence and white finishing integration (color difference ΔE < 2 after 200 h of artificial aging) at a high powder-to-liquid ratio, can replace multiple layers of processes such as leveling, putty and coating, and is suitable for waterproof finishing engineering of water-facing and back-facing surfaces of basements, air defense shelters, pools, kitchens and toilets.

Description

Technical Field

[0001] This invention relates to the field of building waterproofing materials technology, specifically to a functional dual-effect waterproof coating for both front and back water surfaces, and its preparation and construction methods. Background Technology

[0002] Polymer cement (JS) waterproof coatings are made by mixing polymer emulsions and cement-based powders on-site, and are widely used in waterproofing projects for basements, civil defense projects, kitchens and bathrooms, swimming pools, and other buildings. However, existing JS coatings have three prominent problems in practical applications.

[0003] Firstly, there are issues with efflorescence and failure on the back side. Calcium hydroxide in the concrete substrate migrates to the coating surface under capillary action, reacts with carbon dioxide to form calcium carbonate, resulting in efflorescence and whitening, which leads to peeling, loss of gloss, and chalking of the coating. Under negative pressure seepage conditions on the back side, the migration of moisture and calcium salts intensifies, and the impermeability and alkali-suppressing ability of ordinary coatings deteriorate rapidly.

[0004] Secondly, there is a contradiction between the stability and workability of high powder-to-liquid ratio systems. To balance cost and rigid waterproofing performance, engineering projects tend to use high powder-to-liquid ratio systems. However, with the increased powder proportion, ordinary styrene-acrylic emulsions are prone to demulsification in the highly alkaline environment of cement, resulting in more air bubbles during slurry mixing, severe sagging during thick-layer application, and numerous internal pore defects in the coating film, ultimately leading to a decrease in waterproofing density. It is generally accepted in this field that a high powder-to-liquid ratio is difficult to achieve simultaneously with good workability and waterproofing.

[0005] Third, the functions are limited and the procedures are complicated. Existing waterproof coatings only solve the waterproofing problem. For interior walls and ceilings, leveling, puttying, and topcoat application are still required, resulting in many procedures, long construction periods, and high overall costs. In addition, ordinary waterproof layers have poor resistance to yellowing and cannot be used directly as white finishes. Ordinary emulsions have poor coating properties for cement particles and insufficient resistance to chloride ion erosion and durability.

[0006] Therefore, there is an urgent need to develop a functional dual-effect waterproof coating for both the front and back sides of a water-resistant system that combines bidirectional impermeability, long-lasting alkali inhibition, and a white finish under a high powder-to-liquid ratio system, and has excellent construction performance. Summary of the Invention

[0007] To address the aforementioned deficiencies in existing technologies, the present invention aims to provide a functional dual-effect waterproof coating for both the water-facing and back-water-facing sides, along with its preparation and application methods. This invention utilizes a ternary synergistic system design of "functional emulsion + anti-efflorescence additive composition + white mineral powder," simultaneously achieving bidirectional waterproofing on both the water-facing and back-water-facing sides, long-lasting anti-efflorescence inhibition via dual mechanisms, and a white finish on the coating film under high powder-to-liquid ratio conditions.

[0008] The first aspect of this invention provides a functional dual-effect waterproof coating for both water-facing and back-facing surfaces. It is a two-component system consisting of a liquid and a powder, and is used during application by mixing the liquid, powder, and water at a mass ratio of 1:10:(2-2.5). The liquid component comprises 80.0-90.0 wt% of a two-component waterproof emulsion and 10.0-20.0 wt% of an anti-efflorescence waterproofing additive composition. The two-component waterproof emulsion is a silicone-wax hybrid saponified hydrophobic modified emulsion independently developed by the applicant. The anti-efflorescence... The waterproofing additive composition comprises, by weight, 35-50 parts of an organic hydroxycarboxylic acid derivative, 20-30 parts of a nano-silica dispersion with a solid content of 20 wt%, 10-18 parts of a non-APEO polycarboxylate-fatty acid polyethylene glycol composite wetting and dispersing agent, 4-8 parts of an organosilicon-polyether composite defoamer, 6-12 parts of a rheology modifier for water retention composed of a hydrophobic modified associative thickener and a modified cellulose ether, and 2-5 parts of a yellowing-resistant stabilizer composed of a hindered phenolic free radical scavenger and a benzotriazole UV absorber.

[0009] The powder materials include white silicate cement, calcined kaolin, high-whiteness heavy calcium carbonate, and rutile titanium dioxide, etc.

[0010] Furthermore, the two-component waterproof emulsion is a silicone-wax hybrid saponified hydrophobic modified emulsion independently developed and mass-produced by the applicant. This waterproof emulsion is a hybrid emulsion system obtained by high-temperature compatibility and constant-temperature emulsification dispersion of a multi-component silicon-oxygen functional matrix, long-chain alkane crystal components, and long-chain fatty active organic acids under alkaline media conditions. The finished product has an effective solid content of 20±1wt%, a pH value of 7-9, and a viscosity of 1000-2000 mPa·s. It is specifically designed for two-component waterproof coatings and waterproof mortar systems, ensuring standardized supply and stable quality of core raw materials for the coating system. This emulsion is a near-neutral anionic system, exhibiting good compatibility with the strongly alkaline environment of cement and without demulsification. Its long-chain polymers can completely encapsulate cement particles, resulting in a dense film after curing, endowing the coating with bidirectional impermeability, inhibition of chloride ion penetration, corrosion resistance, and crack resistance.

[0011] Furthermore, in the two-component waterproof silicone-wax hybrid saponified hydrophobic modified emulsion, the multi-component siloxane functional matrix is ​​selected from one or more of the following: C3-C12 alkylalkoxysilanes, branched isoalkoxysilane monomers, hydroxyl-terminated siloxane oligomers, methyl-modified polysiloxane prepolymers, cross-linked organosilicon emulsion intermediates, and cyclic siloxane hydrolyzed oligomers. The multi-structured siloxane functional groups can undergo stepwise hydrolysis and gradient condensation in an aqueous system to construct a dense three-dimensional Si-O-Si cross-linked network, possessing multiple functions including interface anchoring, hydrophobic shielding, and weather resistance stability.

[0012] Furthermore, in the two-component waterproof silicone-wax hybrid saponified hydrophobic modified emulsion, the long-chain alkane crystal-type dense hydrophobic component is selected from one or more of C20-C40 normal saturated alkanes, C22-C38 isomeric microcrystalline alkanes, petroleum-based high-melting-point crystalline waxes, and synthetic long-chain alkane eutectics. This component has narrow-range melt crystallization characteristics, and after emulsification, it can precipitate a micron-sized dense hydrophobic crystalline phase in inorganic pores, achieving physical pore sealing.

[0013] Furthermore, in the two-component waterproof silicone-wax hybrid saponified hydrophobic modified emulsion, the long-chain fatty active organic acid is selected from one or more of C16 saturated fatty carboxylic acids, C18 saturated fatty carboxylic acids, C16 / C18 mixed saturated fatty acids, isomerized long-chain fatty organic acids, and plant-derived purified saturated fatty carboxylic acid mixtures. This type of long-chain organic acid can undergo a controllable saponification reaction in an alkaline system to generate water-insoluble long-chain metallic soap crystals, precisely sealing cement-based capillary permeable channels and forming a silicone-wax dual-hybrid waterproof system with the silicone-oxygen crosslinking network.

[0014] Furthermore, in the anti-efflorescence and waterproofing additive composition, the organic hydroxycarboxylic acid derivative is selected from at least one of sodium citrate, sodium pyrophosphate, sodium gluconate, malic acid, and lactic acid, or at least one of the sodium, potassium, and ammonium salts of the above-mentioned hydroxycarboxylic acids. The additive composition complexes and migrates calcium ions through the organic hydroxycarboxylic acid derivative, and the nano-silica reacts with calcium hydroxide in a pozzolanic reaction to generate CSH gel, which seals the capillaries, forming a synergistic anti-efflorescence mechanism of chemical complexation and physical sealing. Simultaneously, it integrates wetting and dispersing, defoaming, rheological water retention, and yellowing resistance stabilization functions, ensuring the dispersibility, construction rheology, and aging resistance of the white finish in the high powder-to-liquid ratio system.

[0015] Further, the powder, by weight, comprises: 40-55 parts white silicate cement, 10-25 parts calcined kaolin, 10-25 parts high-whiteness heavy calcium carbonate, 5-10 parts rutile titanium dioxide, 2-5 parts redispersible latex powder, 0.3-1.0 parts polycarboxylate superplasticizer, and 0.15-0.3 parts polypropylene fiber; the white silicate cement has a strength grade of P·W42.5, the calcined kaolin has a whiteness ≥90, the high-whiteness heavy calcium carbonate has a whiteness ≥92, and the rutile titanium dioxide has a whiteness ≥94. The white mineral powder system imparts high whiteness and a matte finish to the coating film, while the redispersible latex powder further enhances the flexibility and adhesion of the coating film.

[0016] The second aspect of the present invention provides a method for preparing the above-mentioned functional dual-effect waterproof coating for both front and back water surfaces, comprising the steps of liquid preparation (compounding and dispersing an emulsion and an additive composition), powder preparation (mixing dry powders), and separate packaging.

[0017] The third aspect of this invention provides a construction method for the above-mentioned functional dual-effect waterproof coating for both front and back water surfaces, including the steps of substrate treatment, application of a matching special interface agent, slurry preparation, joint reinforcement, application in two coats (total thickness 2.5-5.0 mm, with reinforcing mesh fabric pressed in for thick coating), curing, and water tightness test; the construction environment temperature is 5-35℃, and it can be applied to both dry and damp substrates.

[0018] Compared with the prior art, the beneficial effects of the present invention include at least the following: (1) Bidirectional anti-permeability: The functional emulsion long-chain polymer completely encapsulates the cement particles, and the cured coating is dense. It can withstand the positive pressure on the water-facing side and the negative pressure on the back side of 0.8MPa water pressure for 60 minutes without leakage. The water immersion bonding strength is ≥1.0MPa, and it can firmly adhere to both dry and damp substrates; (2) Long-term alkali suppression: The additive composition has a dual mechanism synergistic effect, which accelerates the efflorescence test to level 1, and eradicates the efflorescence, dampness, whitening and peeling of the wall surface; (3) System stability under high powder-liquid ratio: The near-neutral anionic emulsion and the strong alkali resistant additive package work together to achieve a high powder-liquid ratio of 10:1. The emulsion does not break, the slurry does not bubble, and the thick coating of 2.5-5.0mm does not drip, thus solving the contradiction between the high powder-to-liquid ratio and the difficulty in achieving workability and waterproofing in this field; (4) Integrated finish: The coating film is naturally white and matte and smooth. The color difference ΔE < 2 after 200h of artificial aging can be directly used as interior wall and ceiling finish, replacing the multi-layer process of leveling layer, putty layer and paint layer, and waterproof decoration is formed in one step; (5) Durability and environmental protection: The two-component waterproof emulsion is resistant to chloride ions, corrosion and cracking. The system has low VOC, no free formaldehyde and no APEO. The environmental protection index is better than GB45671-2025, and it can be used safely in closed spaces. Attached Figure Description

[0019] Figure 1 This is a process flow diagram of the construction method of the functional dual-effect waterproof coating for both the front and back water surfaces according to the present invention.

[0020] Figure 2 This is a schematic diagram of the mechanism of the ternary synergistic system of "functional emulsion + anti-alkali efflorescence additive composition + white mineral powder" of the present invention. Detailed Implementation

[0021] The present invention will be further described below with reference to the embodiments. In the following embodiments, the amounts of each component in the liquid are by weight percentage, and the amounts of each component in the additive composition and powder are by weight parts. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0022] The specifications of the main raw materials used in the examples are shown in the table below:

[0023] Two-component waterproof emulsion The emulsion contains a total of 20 wt% composed of a multi-component silicon-oxygen functional matrix, long-chain alkane crystal components, and long-chain aliphatic active organic acids. The finished product has an effective solid content of 20 ± 1 wt%, a pH value of 7–9, and a viscosity of 1000–2000 mPa•s. Organic hydroxycarboxylic acid derivatives Industrial grade, with an effective content ≥98%, selected from at least one of sodium citrate, sodium pyrophosphate, and sodium gluconate. Nano silica dispersion Solid content 20wt%, average particle size 10–50 nm, pH value 9–10.5 Composite wetting and dispersing agents Non-APEO polycarboxylate and fatty acid polyethylene glycol ester are compounded in a mass ratio of 1:1. Organosilicon-polyether composite defoamer Industrial grade, alkali resistant Rheology water retention agent Hydrophobic modified associative thickener and modified cellulose ether are compounded at a mass ratio of 1:1 to 2:1. Yellowing stabilizer Hindered phenolic free radical scavengers and benzotriazole UV absorbers are compounded at a mass ratio of 1:1 to 1:2. White silicate cement Strength rating P·W42.5, whiteness ≥87 Calcinated kaolin Whiteness ≥90, 1250 mesh High whiteness heavy calcium carbonate Whiteness ≥92,800 mesh Rutile titanium dioxide Whiteness ≥94, 325 mesh Redispersible latex powder Vinyl acetate-ethylene copolymer Polycarboxylate superplasticizer Powder, industrial grade Polypropylene fiber Alkali-resistant modified 6mm monofilament, tensile strength at break ≥450MPa

[0024] A general preparation method for an anti-alkali efflorescence and waterproofing additive composition: At room temperature, the reactor is stirred at a low speed of 150-300 rpm, and the organic hydroxycarboxylic acid derivative and nano silica dispersion are added sequentially and stirred for 10 min; the composite wetting and dispersing agent and the organosilicon-polyether composite defoamer are added and stirred for 10 min; the rheology modifier is added and stirred until fully swollen; the yellowing stabilizer is added; the speed is increased to 400-600 rpm and dispersed for 25-35 min, and then filtered and discharged.

[0025] General preparation methods for coatings:

[0026] S1. Liquid preparation: At room temperature, add the two-component waterproof emulsion to the reactor and stir at 150-300 rpm. Add the anti-alkali waterproofing additive composition, increase the speed to 400-600 rpm and disperse for 20-30 minutes. Filter to obtain the liquid.

[0027] S2. Powder preparation: According to the formula, white silicate cement, calcined kaolin, high whiteness heavy calcium carbonate, rutile titanium dioxide, redispersible latex powder, and polycarboxylate superplasticizer are put into a dry powder mixer and mixed for 20 minutes until uniform to obtain powder.

[0028] S3. Liquid and powder materials are sealed and packaged separately.

[0029] Example 1 (Preferred Example)

[0030] Additive composition formula (parts by weight): 42 parts organic hydroxycarboxylic acid derivative, 25 parts nano silica dispersion, 14 parts composite wetting and dispersing agent, 6 parts organic silicone-polyether composite defoamer, 10 parts rheology modifier, and 3 parts yellowing stabilizer. Liquid composition: 85.0 wt% two-component waterproof emulsion and 15.0 wt% additive composition. Powder formulation (parts by weight): 50 parts white silicate cement, 20 parts calcined kaolin, 20 parts high-whiteness heavy calcium carbonate, 7 parts rutile titanium dioxide, 3 parts redispersible latex powder, 0.4 parts polycarboxylic acid water-reducing agent, and 0.25 parts polypropylene fiber. Construction ratio: liquid:powder:water = 1:10:2.2, total coating thickness 3.0 mm, applied in two coats.

[0031] Example 2

[0032] Additive composition formula (parts by weight): 36 parts organic hydroxycarboxylic acid derivative, 29 parts nano-silica dispersion, 17 parts composite wetting and dispersing agent, 4 parts organic silicone-polyether composite defoamer, 11 parts rheology modifier, and 3 parts yellowing stabilizer. Liquid composition: 90.0 wt% emulsion and 10.0 wt% additive composition. Powder composition (parts by weight): 45 parts white silicate cement, 25 parts calcined kaolin, 20 parts high-whiteness heavy calcium carbonate, 5 parts rutile titanium dioxide, 5 parts redispersible latex powder, 0.3 parts polycarboxylic acid water-reducing agent, and 0.3 parts polypropylene fiber. Construction ratio: liquid:powder:water = 1:10:2.5, total coating thickness 2.5 mm, applied in two coats.

[0033] Example 3

[0034] Additive composition formulation (parts by weight): 48 parts organic hydroxycarboxylic acid derivative, 21 parts nano-silica dispersion, 11 parts composite wetting and dispersing agent, 7 parts organosilicon-polyether composite defoamer, 8 parts rheology modifier, and 5 parts yellowing stabilizer. Liquid composition: 80.0 wt% emulsion and 20.0 wt% additive composition. Powder formulation (parts by weight): 55 parts white silicate cement, 15 parts calcined kaolin, 20 parts high-whiteness heavy calcium carbonate, 6 parts rutile titanium dioxide, 4 parts redispersible latex powder, 0.5 parts polycarboxylic acid water-reducing agent, and 0.2 parts polypropylene fiber. Construction ratio: liquid:powder:water = 1:10:2.0, total coating thickness 5.0 mm, applied in two coats and reinforced with alkali-resistant mesh.

[0035] Comparative Example 1

[0036] The only difference from Example 1 is that the two-component waterproof emulsion in the liquid is replaced with an equal amount of commercially available ordinary silicone waterproof emulsion (20wt% solid content), while the rest of the formulation, preparation and construction conditions are the same as in Example 1.

[0037] Comparative Example 2

[0038] The only difference from Example 1 is that the anti-alkali waterproofing additive composition is not added to the liquid material, but is replaced by an equal amount of deionized water. The rest of the formula, preparation and construction conditions are the same as in Example 1.

[0039] Comparative Example 3

[0040] Commercially available ordinary two-component JS waterproof coating, when mixed and applied according to the recommended ratio and process in its instructions, with a coating thickness of 3.0mm.

[0041] The performance test methods are as follows: (1) Impermeability: Refer to the relevant provisions of GB / T 23445 and GB / T 16777, test the leakage of the water-facing side and the back side under 0.8MPa water pressure for 60min respectively; (2) Immersion bonding strength: Test according to GB / T 23445; (3) Accelerated efflorescence test: After curing the 1.5mm thick coating specimen for 7d, place it in an environment of 50℃ and relative humidity ≥90% for 28d of dry and wet cycle, and evaluate it as 1 to 5 levels according to the proportion of efflorescence area; (4) Artificial aging color difference: Aging with xenon lamp for 200h according to GB / T 1865, and measure the color difference ΔE; (5) Coating whiteness: Measured according to GB / T 5950; (6) Thick coating sagging: Apply a wet film with a thickness of 2.5mm on a vertical surface and observe for 30min; (7) Slurry state: Observe the bubbles, layering and demulsification after mixing.

[0042] The performance test results of each embodiment and comparative example are shown in Table 1.

[0043] Table 1 Performance test results of each embodiment and comparative example

[0044] Water-facing surface 0.8MPa / 60min No leakage No leakage No leakage No leakage No leakage No leakage Backwater surface 0.8MPa / 60min No leakage No leakage No leakage Slight water seepage Bubbling seepage Water immersion bond strength ≥1.0MPa ≥1.0MPa ≥1.0MPa 0.7MPa 0.9MPa 0.6MPa Accelerate the efflorescence grade Level 1 Level 1 Level 1 Level 2 Level 4 Level 3 Color difference ΔE after 200 hours of artificial aging ＜2 ＜2 ＜2 ＞4 ＜2 ＞5 Coating whiteness ≥85 ≥85 ≥85 ≥85 ≥85 ＜80 Thick coating and sagging No dripping No dripping No dripping Flowing Slight drips Flowing Slurry state No bubbles, stable No bubbles, stable No bubbles, stable Broken milk, many bubbles Slight stratification More bubbles

[0045] As shown in Table 1, Examples 1-3 of the present invention meet all the standards in terms of bidirectional anti-seepage on both the water-facing and back-facing sides, water immersion bonding, accelerated efflorescence, yellowing resistance, whiteness, and thick coating workability. In Comparative Example 1, after replacing the functional emulsion with ordinary silicone waterproof emulsion, slight water seepage occurred on the back-facing side, the water immersion bonding strength decreased, and the thick coating sag and demulsified, indicating that the two-component waterproof emulsion plays an irreplaceable role in the stability of the high powder-liquid ratio system and the anti-seepage on the back-facing side. In Comparative Example 2, after removing the additive composition, the efflorescence grade deteriorated from level 1 to level 4, and blistering occurred on the back-facing side, indicating that the additive composition is the core of long-term efflorescence inhibition. The commercially available ordinary JS coating in Comparative Example 3 fails to meet the standards in multiple indicators such as anti-seepage on the back-facing side, efflorescence, yellowing, whiteness, and sag. The above comparison shows that the ternary system of "functional emulsion + anti-alkali additive composition + white mineral powder" of the present invention is not a simple superposition of the effects of each component, but achieves the technical effect of bidirectional anti-permeability, long-term alkali inhibition and white finishing under high powder-liquid ratio conditions, which is difficult to achieve simultaneously.

Claims

1. A functional dual-effect waterproof coating for both water-facing and back-facing surfaces, characterized in that, The waterproof coating is a two-component system consisting of liquid and powder. During construction, it is mixed and used at a mass ratio of liquid:powder:water = 1:10:(2~2.5). The liquid component consists of 80.0~90.0wt% of a two-component waterproof emulsion and 10.0~20.0wt% of an anti-efflorescence waterproofing additive composition by mass percentage. The two-component waterproof emulsion is a silicone-wax hybrid saponified hydrophobic modified emulsion independently developed by the applicant. The anti-alkali and waterproofing additive composition comprises, by weight, 35-50 parts of an organic hydroxycarboxylic acid derivative, 20-30 parts of a nano-silica dispersion with a solid content of 20 wt%, 10-18 parts of a non-APEO polycarboxylate-fatty acid polyethylene glycol composite wetting and dispersing agent, 4-8 parts of an organosilicon-polyether composite defoamer, 6-12 parts of a rheology modifier for water retention composed of a hydrophobic modified associative thickener and a modified cellulose ether, and 2-5 parts of a yellowing-resistant stabilizer composed of a hindered phenolic free radical scavenger and a benzotriazole UV absorber; the powder comprises white silicate cement, calcined kaolin, and high-whiteness heavy calcium carbonate.

2. The functional dual-effect waterproof coating for both front and back water surfaces according to claim 1, characterized in that, The two-component waterproof silicone-wax hybrid saponified hydrophobic modified emulsion is not a commercially available silicone wax raw material, nor is it obtained by simply mixing organosilicon emulsion and paraffin emulsion in the later stage; rather, it is a hybrid emulsion system obtained by high-temperature compatibility and constant-temperature emulsification dispersion of multi-dimensional silicon-oxygen functional matrix, long-chain alkane crystal components, and long-chain fatty active organic acids under alkaline medium conditions.

3. The multi-component siloxane functional matrix according to claim 2 is selected from one or more of C3-C12 alkylalkoxysilanes, branched isoalkoxysilane monomers, hydroxyl-terminated siloxane oligomers, methyl-modified polysiloxane prepolymers, cross-linked organosilicon emulsion intermediates, and cyclic siloxane hydrolysed oligomers; the long-chain alkane crystal form dense hydrophobic component is selected from one or more of C20-C40 normal saturated alkanes, C22-C38 isomeric microcrystalline alkanes, petroleum-based high-melting-point crystalline waxes, and synthetic long-chain alkane eutectics; the long-chain fatty active organic acid is selected from one or more of C16 saturated fatty carboxylic acids, C18 saturated fatty carboxylic acids, C16 / C18 mixed saturated fatty acids, isomerized long-chain fatty organic acids, and plant-derived purified saturated fatty carboxylic acid mixtures.

4. The functional dual-effect waterproof coating for both front and back water surfaces according to claim 1 or 2, characterized in that, The effective solids content of the two-component waterproof emulsion is 20±1wt%, the pH value is 7~9, and the viscosity is 1000~2000mPa·s.

5. The functional dual-effect waterproof coating for both front and back water surfaces according to claim 1, characterized in that, The organic hydroxycarboxylic acid derivative is selected from at least one of citric acid, sodium pyrophosphate, gluconic acid, malic acid, and lactic acid, or at least one of the sodium, potassium, and ammonium salts of the above hydroxycarboxylic acids.

6. The functional dual-effect waterproof coating for both front and back water surfaces according to claim 1, characterized in that, The powder, by weight, comprises: 40-55 parts white silicate cement, 10-25 parts calcined kaolin, 10-25 parts high-whiteness heavy calcium carbonate, 5-10 parts rutile titanium dioxide, 2-5 parts redispersible latex powder, 0.3-1.0 parts polycarboxylate superplasticizer, and 0.15-0.3 parts polypropylene fiber.

7. The functional dual-effect waterproof coating for both front and back water surfaces according to claim 6, characterized in that, The strength grade of the white silicate cement is P·W42.5; the whiteness of the calcined kaolin is ≥90, the whiteness of the high-whiteness heavy calcium carbonate is ≥92, and the whiteness of the rutile titanium dioxide is ≥94.

8. A method for preparing a functional dual-effect waterproof coating for both front and back water surfaces as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Liquid preparation: At room temperature, add the two-component waterproof emulsion to the reactor and stir at 150-300 rpm. Add the anti-alkali waterproofing additive composition, increase the speed to 400-600 rpm and disperse for 20-30 minutes. Filter to obtain the liquid. S2. Powder preparation: Add white silicate cement, calcined kaolin, high whiteness heavy calcium carbonate, rutile titanium dioxide and optional components to a dry powder mixer and mix until uniform to obtain powder; S3. Seal and package the liquid and powder separately.

9. A method for applying the functional dual-effect waterproof coating for both front and back water surfaces as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Base treatment: The base surface should be firm and flat. Cracks larger than 0.3mm should be repaired first. The inside and outside corners and the roots of pipes penetrating the wall should be rounded with R5 to R10. The base surface is allowed to be damp, but there should be no standing water on the surface. S2. Apply the matching special interface agent and wait for it to dry completely to form the anchoring surface; S3. Slurry preparation: According to the mass ratio of liquid material: powder material: water = 1:10: (2~2.5), first mix the liquid material with water, then add the powder material while stirring, and mechanically stir for no less than 5 minutes until there are no dry powder particles. Let it stand for 3 minutes and then stir again for 1 minute. The prepared slurry should be used up within 4 hours. S4. Node reinforcement: Apply two thin coats of slurry to the inside and outside corners, through-wall pipes, and construction joints, and lay an additional layer of alkali-resistant mesh or polyester non-woven fabric with a width of ≥200mm in the middle. S5. Apply the coating in two coats to form a large surface, with a total coating thickness of 2.5–5.0 mm; when the thickness is 5.0 mm, apply the coating in two coats and press in alkali-resistant mesh or polyester non-woven fabric for reinforcement. S6. Curing at room temperature for 72 hours, and curing the structure under long-term immersion in water for 7 days; S7. Fill the tank with 20-30mm of water and conduct a 24-hour water tightness test. No leakage is acceptable.

10. The construction method according to claim 9, characterized in that, The ambient temperature during construction is 5–35℃.

11. The application of the functional dual-effect waterproof coating for both water-facing and back-water-facing surfaces as described in any one of claims 1-7 in the integrated construction of waterproof finishing on the water-facing and back-water-facing surfaces of damp basements, basements, civil defense projects, indoor pools, or kitchen and bathroom surfaces.

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