A polymer waterproof coating and a preparation method thereof

Abstract

This application specifically discloses a polymer waterproof coating and its preparation method. The polymer waterproof coating comprises a powder and a liquid, wherein the powder comprises slag powder, and the liquid comprises an alkali-activated modified bio-based emulsion; the mass ratio of the powder to the liquid is (2.3-2.5):1. The polymer waterproof coating provided by this application maintains excellent waterproof performance while significantly reducing product carbon emissions, achieving a balance between high performance and low carbon emissions in waterproof coatings, and also exhibits good storage stability and construction adaptability.

Description

Technical Field

[0001] This application relates to the field of coating technology, and in particular to a polymer waterproof coating and its preparation method. Background Technology

[0002] Polymer cement-based waterproof coatings, also commonly known as JS waterproof coatings, are a type of material widely used in building waterproofing projects. These coatings are typically composed of polymer emulsions and inorganic cementitious materials such as cement, forming an elastic film with waterproofing properties after application. Currently, most JS waterproof coatings on the market typically contain a large amount of ordinary silicate cement in the powder component, while the liquid component mainly uses acrylic polymer emulsions. These components together constitute the main framework of existing JS waterproof coatings, which are widely used in the field of building waterproofing.

[0003] However, existing JS waterproof coatings have certain limitations in raw material acquisition and production. The cement industry's production process involves significant resource consumption and carbon dioxide emissions. Its clinker calcination stage requires the consumption of large amounts of fossil energy, and the decomposition of limestone raw materials also directly generates carbon dioxide. On the other hand, the upstream raw materials for acrylic emulsions rely entirely on the refining of fossil resources such as petroleum. The entire industrial chain, from crude oil extraction, cracking, and distillation to emulsion polymerization, also has high energy consumption intensity and is accompanied by significant carbon dioxide emissions.

[0004] Therefore, how to prepare more environmentally friendly polymer waterproof coatings while maintaining the basic performance of waterproof coatings is a technical direction worthy of attention in the industry. Summary of the Invention

[0005] To address the problems in the prior art, this application provides a polymer waterproof coating and a method for preparing the same.

[0006] In a first aspect, this application provides a polymer waterproof coating, which adopts the following technical solution: A polymer waterproof coating includes a powder and a liquid, wherein the powder comprises slag powder and the liquid comprises an alkali-activated modified bio-based emulsion; the mass ratio of the powder to the liquid is (2.3-2.5):1.

[0007] The polymer waterproof coating provided in this application uses slag powder to completely replace traditional cement as the inorganic cementitious material. The main components of slag powder are CaO, SiO2, and Al2O3. Its glassy structure undergoes depolymerization and polycondensation reactions under the action of an alkali activator: the alkali activator raises the pH value of the system to above 12, breaking the Si-O and Al-O bonds in the slag glass, and dissolving Si... 4+ Al 3+ Ca 2+The active ions, through condensation reactions, generate CSH gel and CASH gel with a three-dimensional network structure, ultimately forming a dense, hardened body that achieves strong adhesion to the substrate and efficient waterproofing. Simultaneously, the liquid agent used in this application is an alkali-activated, modified bio-based emulsion. This allows the active ions (such as SiO3) released from the alkali activator to... 2- or / and OH - During storage, the SiO3 is encapsulated by polymer chains, preventing hydrolysis or precipitation and significantly improving storage stability. On the other hand, the SiO3 released after the alkali activator dissociates... 2- and OH - The agent is uniformly distributed along the polymer chain and can be evenly released after mixing with slag powder, resulting in high activation efficiency. The formed CASH gel interpenetrates with the polymer network, significantly enhancing interfacial bonding. Based on this, this application controls the mass ratio of powder to liquid at 2.3-2.5:1 to ensure sufficient alkali activation reaction and good slurry workability. This application achieves excellent tensile strength, bond strength, and impermeability by utilizing the synergistic effect of industrial by-product slag powder and alkali-activated modified bio-based emulsion, without relying on high-carbon-emission cement. Simultaneously, it significantly reduces the total carbon emissions of the formulation, truly achieving a balance between high performance and low carbon emissions in waterproof coating products.

[0008] Preferably, the powder further includes inorganic fillers and water-reducing agents.

[0009] This application further incorporates inorganic fillers and water-reducing agents into the powder formulation to optimize the coating's workability and physical and mechanical properties. The inorganic fillers, acting as aggregates, reduce the shrinkage rate of the coating during drying and enhance its crack resistance. The water-reducing agent improves the fluidity of the slurry and reduces water demand, thereby increasing the density and mechanical strength of the hardened body. The coating containing these components exhibits a moderate initial viscosity and a significantly extended open time, greatly facilitating on-site construction while ensuring the dimensional stability and mechanical strength of the cured coating. This allows the coating to possess its core low-carbon waterproofing function while demonstrating excellent application adaptability.

[0010] Preferably, the inorganic filler includes at least one of 70-140 mesh quartz sand, 300-400 mesh heavy calcium carbonate, 300-500 mesh talc powder, and 600-800 mesh barium sulfate.

[0011] This application further optimizes the particle size distribution and bulk density of the powder system by adjusting the types of inorganic fillers. Coarse-grained quartz sand can form a skeletal support structure in the coating, effectively resisting stress generated by drying shrinkage; fine-grained heavy calcium carbonate, talc, or barium sulfate can fill the gaps in the skeletal structure, significantly improving the density and impermeability of the coating. A reasonable filler combination can also improve the rheological behavior of the coating, ensuring a uniform and stable slurry after mixing the liquid and powder, avoiding stratification and sedimentation, thereby guaranteeing the uniformity of construction quality and the long-term durability of the coating.

[0012] Preferably, the liquid further includes at least one of a dispersant, a mineral oil defoamer, a preservative, a blue pigment, and water.

[0013] This application comprehensively improves the processing stability, storage stability, and application visibility of the coating by compounding multiple functional additives into the liquid formulation. The dispersant ensures that the mineral powder and filler remain uniformly suspended in the liquid for a long period, effectively preventing sedimentation and stratification; the mineral oil defoamer inhibits the generation of bubbles during stirring and brushing, avoiding pinhole defects in the coating film and ensuring its integrity; the preservative prevents the coating from becoming moldy and spoiled under humid storage conditions, extending the product's shelf life; and the blue pigment allows construction personnel to visually identify the coating area, ensuring uniform and complete application. The synergistic effect of these additives enables the coating of this application to exhibit excellent comprehensive application performance in addition to its core waterproofing function, meeting the diverse needs of industrial production and on-site construction.

[0014] Preferably, the polymer waterproof coating comprises a powder and a liquid, calculated by weight percentage as follows: the powder comprises 40%-45% slag powder, 15%-25% 70-140 mesh quartz sand, 0.1%-0.3% water-reducing agent, and 200 mesh heavy calcium carbonate to make up to 100%; the liquid comprises 90%-95% alkali-activated modified bio-based emulsion, 0.3%-0.6% dispersant, 0.1%-0.2% mineral oil defoamer, 0.3%-0.5% preservative, 0.3%-0.5% blue pigment, and water to make up to 100%.

[0015] Preferably, the water-reducing agent includes at least one of lignin sulfonate water-reducing agents, polycyclic aromatic salt water-reducing agents, water-soluble resin sulfonate water-reducing agents, and polycarboxylate water-reducing agents.

[0016] Preferably, the dispersant comprises a hydrophobically modified copolymer ammonium salt dispersant.

[0017] Preferably, the mineral oil defoamer is selected from Nopco's NXZ.

[0018] Preferably, the bactericidal and preservative agent is an isothiazolinone, selected from MERGAL K14 of Troy Corporation, USA.

[0019] Preferably, the alkali-activated modified bio-based emulsion is prepared by a method comprising the following steps: S1, after mixing bio-based butyl acrylate, styrene, methyl methacrylate, itaconic acid, and methacryloyloxyethyltrimethylammonium chloride, a cationic emulsifier and deionized water are added, and the mixture is emulsified to obtain a pre-emulsion. S2, a portion of the pre-emulsion is mixed with a portion of the initiator solution for emulsion polymerization, and then the remaining portion of the pre-emulsion and the remaining portion of the initiator solution are added dropwise to carry out the polymerization reaction, thereby obtaining a cationic bio-based styrene-acrylic emulsion; S3, the alkaline activator solution is added dropwise to the cationic bio-based styrene-acrylic emulsion, and the mixture is stirred after the addition is complete to obtain a composite emulsion; S4. Add the silane coupling agent dropwise to the composite emulsion, mix, and stir to obtain the final product.

[0020] Bio-based butyl acrylate refers to a product prepared from renewable biomass resources (such as, but not limited to, corn, wood, straw, vegetable oil, etc.) through bio-fermentation, chemical conversion, or a combination of both. This definition conforms to the general definition of bio-based chemicals in GB / T39514-2020 "Terminology, Definition and Identification of Bio-based Materials".

[0021] Preferably, the bio-based butyl acrylate of this application is purchased from Hechuang Chemical; the bio-based content in the bio-based butyl acrylate of this application is 25%-35%.

[0022] The alkali-activated modified bio-based emulsion prepared by the process described in this application solves the technical problems of poor storage stability and low activation efficiency caused by direct mixing of conventional alkali activators with emulsions. Specifically, the first two steps synthesize a positively charged cationic bio-based styrene-acrylic emulsion; in the third step, the positively charged latex particles can efficiently electrostatically adsorb the negatively charged alkali activator anions, achieving uniform distribution of the activator on the surface of the latex particles; in the fourth step, a silane coupling agent forms a cross-linked network on the surface of the latex particles, encapsulating the activator inside the shell and effectively preventing hydrolysis or precipitation during storage. During construction, this structure slowly releases the activator under alkaline conditions and mechanical stirring, reacting with slag powder to form a dense structure of interpenetrating CASH gel and polymer network, significantly enhancing the interfacial bonding force, thereby significantly improving the mechanical properties of the coating film, such as tensile strength, elongation at break, and adhesive strength. Simultaneously, the coating prepared using this method exhibits a significantly longer open time than commercially available products, demonstrating that the storage stability and construction adaptability of this application are both excellent.

[0023] Preferably, in S1, the bio-based butyl acrylate, the styrene, the methyl methacrylate, the itaconic acid, and the methacryloyloxyethyltrimethylammonium chloride are mixed in a mass ratio of 50%-75%: 15%-30%: 10%-25%: 3%-5%: 1%-2.5%. The cationic emulsifier accounts for 2%-3% of the total mass of the monomers mentioned above; Preferably, the cationic emulsifier includes at least one of hexadecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, dodecyldimethylbenzylammonium chloride, and benzalkonium chloride.

[0024] Preferably, the emulsification process includes shearing at 8000-10000 rpm for 10-15 minutes.

[0025] This application synthesizes cationic bio-based styrene-acrylic emulsions with uniform particle size and excellent surface charge characteristics by limiting monomer ratios and emulsification process parameters. High-speed shear emulsification ensures the miniaturization and uniform distribution of monomer droplets, laying a good foundation for subsequent seed polymerization. The introduction of itaconic acid provides carboxyl active sites for later crosslinking of the latex particles. The addition of cationic functional monomers gives the latex particle surface a stable positive charge, which is the key technical basis for its efficient electrostatic adsorption of anionic alkali activators. The comprehensive control of the above parameters ensures that the latex particles have a suitable particle size range and good colloidal stability, providing structural protection for achieving uniform loading and stable storage of the activator.

[0026] Preferably, the temperature for emulsion polymerization in S2 is 70-75°C, and the holding time is 25-30 min.

[0027] Preferably, the subsequent dripping process lasts for 2-3 hours, the temperature during the dripping process is 75-80℃, and after the dripping process is completed, the temperature is raised to 85-88℃ and kept at that temperature for 1-2 hours.

[0028] This application achieves a stable cationic emulsion with high conversion rate and low agglomerate content by controlling the temperature and time of seed polymerization and continuous dropwise polymerization. During the seed polymerization stage, stable and controllable latex particle cores are formed at a relatively low temperature, and holding at this temperature for a certain time ensures uniform seed particle size. The continuous dropwise polymerization stage is conducted at a slightly higher temperature for a longer time to ensure uniform and stable monomer growth and avoid localized agglomeration. Finally, heating and holding at this temperature promotes complete reaction of residual monomers, reducing the free monomer content. The emulsion prepared by this process has a narrow particle size distribution, high conversion rate, and good storage stability. Even after subsequent grafting of activators and crosslinking treatment, it maintains excellent flowability and chemical stability, meeting the batch stability requirements for industrial production.

[0029] Preferably, the initiator in S2 includes at least one of azobisisobutyramidine hydrochloride (AIBI) and azobisisobutyramidine hydrochloride (AIBA).

[0030] Preferably, the portion of the pre-emulsion undergoing emulsion polymerization in S2 accounts for 10%-20% of the total mass of the pre-emulsion.

[0031] Preferably, the concentration of the initiator solution in S2 is 5%wt-10wt.

[0032] Preferably, the total mass of the initiator in the initiator solution in S2 accounts for 0.2%-0.3% of the total mass of the preemulsion.

[0033] Preferably, the alkaline activator in the alkaline activator solution in S3 includes at least one of sodium hydroxide, sodium silicate, sodium metasilicate, lithium silicate, and sodium carbonate.

[0034] This application utilizes specific types of alkali activators to regulate the hydration reaction process of slag powder and the structure of the gel product. These alkali activators, upon dissolving in water, release hydroxide ions, raising the system pH to approximately 12. This effectively disrupts the silicon-oxygen and aluminum-oxygen bonds in the slag glass, promoting the dissolution and condensation of active ions to form CSH and CASH gels with a three-dimensional network structure. In particular, silicate activators can continuously and slowly release alkaline components after liquid-powder mixing, extending the workable time of the slurry, preventing premature thickening during construction, and ensuring the strength and density of the final hardened body. This allows the coating of this application to achieve stable and reliable waterproofing effects under various construction conditions.

[0035] Preferably, the concentration of the alkaline activator solution in S3 is 12%-20%, and the pH value is 11-12; the mass ratio of the alkaline activator solution to the cationic bio-based styrene-acrylic emulsion is 1:(9-10).

[0036] This application achieves efficient and uniform saturated adsorption of the activator on the surface of cationic latex particles by controlling the concentration, pH value, dropping rate, and stirring speed of the alkali activator solution. Specific ranges for activator concentration and pH value ensure complete dissociation of the activator into an active anionic state; slow dropping combined with moderate stirring speed avoids emulsion flocculation or demulsification caused by localized over-concentration or strong shear; after dropping, stirring continues for a certain period to allow adsorption to reach equilibrium. After adsorption equilibrium, the surface potential of the latex particles shows a regular change, indicating that the activator has been firmly adsorbed onto the latex particle surface. This process ensures that each latex particle is loaded with a sufficient amount and uniformly distributed activator anions, providing a structural basis for the subsequent uniform and controllable alkali-activated reaction of the coating.

[0037] The dripping process lasts for 30-60 minutes, and the stirring speed during the dripping process is 300-500 rpm; after the dripping is completed, continue stirring for 30-40 minutes.

[0038] Preferably, the mass of the silane coupling agent in S4 accounts for 0.4%-0.6% of the total mass of the composite emulsion; This application constructs a dense cross-linked network shell on the surface of latex particles through a cross-linking reaction using a silane coupling agent under mild conditions. This shell acts as a physical coating, firmly locking the electrostatically adsorbed activator anions onto the latex particle surface, effectively preventing desorption or premature hydrolysis and deactivation in long-term aqueous storage media. Simultaneously, this cross-linked network enhances the mechanical strength and freeze-thaw stability of the latex particles, ensuring the modified emulsion maintains stable performance during long-term storage. During application, the cross-linked layer can slowly release activator anions (such as OH-) under alkaline conditions and mechanical stirring. - SiO3 2- (etc.), achieving a perfect balance between activation function and storage stability.

[0039] Preferably, the silane coupling agent in S4 is added over a period of 15-25 minutes; after the silane coupling agent is added, the mixture is stirred at 40-50°C for 1-2 hours.

[0040] Secondly, this application provides a method for preparing a polymer waterproof coating, which adopts the following technical solution: A method for preparing a polymer waterproof coating includes the following steps: (1) Prepare powder and liquid formulations separately for later use; The preparation of the powder includes the following steps: After mixing the slag powder and the inorganic filler, stir, and then add the water-reducing agent and stir to obtain a powder.

[0041] The preparation of the liquid includes the following steps: A1. Stir the alkali activator-modified bio-based emulsion at low speed, and add the preservative, the dispersant, the defoamer, and the color paste into the alkali activator-modified bio-based emulsion while stirring. A2, continue adding water to the above mixture and stir continuously to obtain a liquid; (2) Mix the above powder with the above liquid to obtain a polymer waterproof coating. Attached Figure Description

[0042] Figure 1 The images show the alkali return test results of the coatings of Example 1 (a) and the commercially available product of Comparative Example 6 (b).

[0043] Figure 2The images show the crack resistance test results of the coatings of Example 1 (a) and the commercially available product of Comparative Example 6 (b). Detailed Implementation

[0044] To better understand and implement this application, the technical solutions of this application will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only some of the embodiments of this application, and not all of them.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0046] Unless otherwise stated, all numerical values ​​for the amounts of expressed components, reaction conditions, etc., used in the specification and claims are to be understood as being modified by the term "about". Therefore, unless otherwise indicated, the numerical parameters set forth herein are approximate values ​​that can be varied to obtain the desired performance.

[0047] The word “and / or” as used in this article refers to one or all of the elements mentioned.

[0048] The terms "include" and "contain" as used in this article cover both cases where only the mentioned elements exist and cases where there are other unmentioned elements in addition to the mentioned elements.

[0049] All percentages in this application are weight percentages unless otherwise stated.

[0050] Unless otherwise stated, the terms “a,” “an,” “an,” and “the” as used in this specification are intended to include “at least one” or “one or more.” For example, “a component” refers to one or more components, and therefore more than one component may be considered and may be employed or used in the implementation of the described embodiments.

[0051] Example 1 A polymer waterproof coating comprises a powder and a liquid in a mass ratio of 2.5:1. By weight percentage, the powder comprises 45% slag powder, 25% 70-140 mesh quartz sand, 0.3% water-reducing agent (lignin sulfonate water-reducing agent), and 300-400 mesh heavy calcium carbonate to make up to 100%; By weight percentage, the liquid comprises 95% alkali-activated modified bio-based emulsion, 0.6% dispersant (hydrophobic modified copolymer ammonium salt dispersant), 0.2% mineral oil defoamer (Nopco NXZ), 0.5% preservative (Troy MERGAL K14), 0.5% blue pigment, and water to make up to 100%.

[0052] The preparation method of alkali-activated modified bio-based emulsion includes the following steps: S1, Bio-based butyl acrylate, styrene, methyl methacrylate, itaconic acid, and methacryloyloxyethyltrimethylammonium chloride are mixed in a mass ratio of 65%:18%:12%:3%:2%, and then cationic emulsifier (hexadecyltrimethylammonium bromide) and deionized water are added, accounting for 3% of the total mass of the above monomers. The mixture is sheared at 8000 rpm for 15 min to obtain a pre-emulsion. S2, a portion of the pre-emulsion (accounting for 20% of the total mass of the pre-emulsion) and a portion of the initiator solution (the initiator solution concentration is 10wt%, and the initiator in the initiator solution is AIBI; the mass of AIBI in the above-mentioned partial initiator solution accounts for 0.2% of the mass of the above-mentioned partial pre-emulsion) are mixed, heated to 75℃, and kept at this temperature for 30 min; then the remaining portion of the pre-emulsion and the remaining portion of the initiator solution (the mass of AIBI in the above-mentioned remaining portion of the initiator solution accounts for 0.2% of the mass of the above-mentioned remaining portion of the pre-emulsion) are added dropwise to the above-mentioned mixed system, the dropwise addition time is 2 h, the temperature is 80℃, after the dropwise addition is completed, the temperature is raised to 88℃, kept at this temperature for 1 h, cooled to room temperature, and filtered to obtain a cationic bio-based styrene-acrylic emulsion; S3, weigh out the alkaline activator solution and cationic bio-based styrene-acrylic emulsion at a mass ratio of 1:10, and set aside; The alkaline activator solution (12% sodium hydroxide aqueous solution, pH value 11-12) was added dropwise to the cationic bio-based styrene-acrylic emulsion (the mass ratio of alkaline activator solution to cationic bio-based styrene-acrylic emulsion was 1:9). The addition was completed in 30 minutes with a stirring speed of 500 rpm, and stirring was continued for another 30 minutes to obtain the composite emulsion. S4. Weigh out 0.6% of the total mass of the composite emulsion of silane coupling agent (γ-glycidoxypropyltrimethoxysilane) and set aside. The silane coupling agent (γ-glycidoxypropyltrimethoxysilane) was diluted with ethanol and then added dropwise to the composite emulsion. The dropwise addition process lasted for 20 minutes, and the mixture was stirred at 50°C for 1 hour to obtain the final product.

[0053] A polymer waterproof coating, the preparation method of which includes the following steps: (1) Prepare powder and liquid formulations separately for later use; The preparation of the powder includes the following steps: The slag powder and the inorganic filler are mixed and stirred at 600 rpm. The water-reducing agent is then added and stirred at 600 rpm to obtain a powder.

[0054] The preparation of the liquid includes the following steps: A1. Stir the alkali activator modified bio-based emulsion at 600 rpm, and add the preservative, the dispersant, the defoamer, and the color paste into the alkali activator modified bio-based emulsion while stirring. A2, continue adding water to the above mixture and stir continuously at 600 rpm to obtain a liquid; (2) Mix the above powder with the above liquid to obtain a polymer waterproof coating.

[0055] The coating efflorescence test results of this embodiment are shown in the figure below. Figure 1 As shown; the coating crack resistance test results of this embodiment are shown in the figure. Figure 2 As shown.

[0056] Example 2 A polymer waterproof coating comprises a powder and a liquid in a mass ratio of 2.3:1. By weight percentage, the powder comprises 40% slag powder, 15% 70-140 mesh quartz sand, 0.1% water-reducing agent (lignin sulfonate water-reducing agent), and 300-400 mesh heavy calcium carbonate to make up to 100%; By weight percentage, the liquid comprises 90% alkali-activated modified bio-based emulsion, 0.3% dispersant (hydrophobic modified copolymer ammonium salt dispersant), 0.1% mineral oil defoamer (Nopco NXZ), 0.3% preservative (Troy MERGAL K14), 0.3% blue pigment, and water to make up to 100%.

[0057] The preparation method of alkali-activated modified bio-based emulsion includes the following steps: S1, Bio-based butyl acrylate, styrene, methyl methacrylate, itaconic acid, and methacryloyloxyethyltrimethylammonium chloride are mixed in a mass ratio of 68%:15%:10%:5%:2%, and then cationic emulsifier (dodecyltrimethylammonium chloride) and deionized water are added, accounting for 2% of the total mass of the above monomers. The mixture is sheared at 10000 rpm for 10 min to obtain a pre-emulsion. S2, a portion of the pre-emulsion (10% of the total mass of the pre-emulsion) is mixed with a portion of the initiator solution (5wt% concentration of the initiator solution, AIBA as the initiator, and the mass of AIBA in the initiator solution is 0.3% of the mass of the pre-emulsion), heated to 70°C, and held for 25 min; then the remaining portion of the pre-emulsion and the remaining portion of the initiator solution (the mass of AIBA in the remaining initiator solution is 0.3% of the mass of the remaining portion of the pre-emulsion) are added dropwise to the above mixture over 3 h at 75°C. After the addition is complete, the temperature is raised to 85°C and held for 1 h. The mixture is then cooled to room temperature and filtered to obtain a cationic bio-based styrene-acrylic emulsion. S3, weigh out the alkaline activator solution and cationic bio-based styrene-acrylic emulsion at a mass ratio of 1:10, and set aside; The alkaline activator solution (20% sodium hydroxide aqueous solution, pH value 11-12) was added dropwise to the cationic bio-based styrene-acrylic emulsion (the mass ratio of alkaline activator solution to cationic bio-based styrene-acrylic emulsion was 1:11). The addition was completed in 60 minutes with a stirring speed of 300 rpm, and stirring was continued for 30 minutes to obtain the composite emulsion. S4. Weigh out 0.6% of the total mass of the composite emulsion of silane coupling agent (γ-glycidoxypropyltrimethoxysilane) and set aside. The silane coupling agent (γ-glycidoxypropyltrimethoxysilane) was diluted with ethanol and then added dropwise to the composite emulsion. The dropwise addition process lasted for 25 minutes, and the mixture was stirred at 50°C for 1 hour to obtain the final product.

[0058] A polymer waterproof coating, the preparation method of which includes the following steps: (1) Prepare powder and liquid formulations separately for later use; The preparation of the powder includes the following steps: The slag powder and the inorganic filler are mixed and stirred at 400 rpm. The water-reducing agent is then added and stirred at 400 rpm to obtain a powder.

[0059] The preparation of the liquid includes the following steps: A1. Stir the alkali activator modified bio-based emulsion at 400 rpm, and add the preservative, the dispersant, the defoamer, and the color paste into the alkali activator modified bio-based emulsion while stirring. A2, continue adding water to the above mixture and stir continuously at 400 rpm to obtain a liquid; (2) Mix the above powder with the above liquid to obtain a polymer waterproof coating.

[0060] Example 3 The difference between this embodiment and Embodiment 1 is that talc powder of equal mass ratio is used instead of heavy calcium carbonate, while the other steps and parameter settings are consistent with Embodiment 1.

[0061] Example 4 The difference between this embodiment and Embodiment 1 is that barium sulfate of equal mass percentage is used instead of heavy calcium carbonate, while the other steps and parameter settings are consistent with Embodiment 1.

[0062] Example 5 The difference between this embodiment and Embodiment 1 is that an aqueous solution of sodium silicate of equal mass and concentration is used instead of the aqueous solution of sodium hydroxide, while the other steps and parameter settings are consistent with Embodiment 1.

[0063] Example 6 The difference between this embodiment and Embodiment 1 is that an aqueous solution of sodium carbonate of equal mass and concentration is used instead of the aqueous solution of sodium hydroxide, while the other steps and parameter settings are consistent with Embodiment 1.

[0064] Example 7 The difference between this embodiment and Embodiment 1 is that equal masses of sodium silicate aqueous solution and sodium carbonate aqueous solution are used instead of the sodium hydroxide aqueous solution (the mass ratio of sodium silicate aqueous solution and sodium carbonate aqueous solution is 1:1). All other steps and parameter settings are consistent with Embodiment 1.

[0065] Example 8 The difference between this embodiment and Example 1 is that, in the preparation method of the polymer waterproof coating, bio-based butyl acrylate, styrene, methyl methacrylate, itaconic acid, and methacryloyloxyethyltrimethylammonium chloride are mixed in S1 at a mass ratio of 80%:10%:5%:3%:2%. All other steps and parameter settings are consistent with those in Example 1.

[0066] Example 9 The difference between this embodiment and Embodiment 1 is that, in the preparation method of the polymer waterproof coating, in S2, all the pre-emulsion and all the initiator solution are mixed at once. All other steps and parameter settings are consistent with those in Example 1.

[0067] Example 10 The difference between this embodiment and Example 1 is that, in the preparation method of the polymer waterproof coating, the concentration of the alkali activator solution in S3 is 8%; All other steps and parameter settings are consistent with those in Example 1.

[0068] Example 11 The difference between this embodiment and Example 1 is that, in the preparation method of the polymer waterproof coating, the concentration of the alkali activator solution in S3 is 25%; All other steps and parameter settings are consistent with those in Example 1.

[0069] Example 12 The difference between this embodiment and Embodiment 1 is that, in the preparation method of the polymer waterproof coating, the silane coupling agent and the composite emulsion are directly mixed in one step in S4. All other steps and parameter settings are consistent with those in Example 1.

[0070] Example 13 The difference between this embodiment and Embodiment 1 is that, in the preparation method of the polymer waterproof coating, the mass of the silane coupling agent in S4 accounts for 0.2% of the total mass of the composite emulsion; All other steps and parameter settings are consistent with those in Example 1.

[0071] Example 14 The difference between this embodiment and Embodiment 1 is that, in the preparation method of the polymer waterproof coating, the mass of the silane coupling agent in S4 accounts for 0.8% of the total mass of the composite emulsion; All other steps and parameter settings are consistent with those in Example 1.

[0072] Comparative Example 1 The difference between this embodiment and Embodiment 1 is that cement of equal mass ratio is used instead of slag powder; all other steps and parameter settings are consistent with Embodiment 1.

[0073] Comparative Example 2 The difference between this embodiment and Example 1 is that a cationic bio-based styrene-acrylic emulsion (prepared in S2) with an equal mass ratio is used instead of the alkali activator-modified bio-based emulsion; all other steps and parameter settings are consistent with Example 1.

[0074] Comparative Example 3 The difference between this embodiment and Embodiment 1 is that the alkali activator solution and the cationic bio-based styrene-acrylic emulsion are mixed in equal mass proportions in a single step instead of the alkali activator-modified bio-based emulsion used in the coating; all other steps and parameter settings are consistent with Embodiment 1.

[0075] Comparative Example 4 The difference between this embodiment and Embodiment 1 is that the mass ratio of powder to liquid is 2:1; all other steps and parameter settings are consistent with Embodiment 1.

[0076] Comparative Example 5 The difference between this embodiment and Embodiment 1 is that the mass ratio of powder to liquid is 3:1; all other steps and parameter settings are consistent with Embodiment 1.

[0077] Comparative Example 6 This embodiment uses commercially available polymer waterproof coatings. The difference between the commercially available polymer waterproof coatings and the polymer waterproof coatings of Example 1 is that, in the powder form, cement is used in place of slag powder in an equal mass ratio, and in the liquid form, conventional styrene-acrylic emulsion is used in place of alkali-activated modified bio-based emulsion in an equal mass ratio.

[0078] The coating efflorescence test results of this comparative example are shown in the figure below. Figure 1 As shown; the crack resistance test results of the coating in this comparative example are shown in the figure. Figure 2 As shown.

[0079] Test methods 1. Referring to GB / T23445-2025 Polymer Cement Waterproof Coating, the waterproof coatings in the above examples were tested for Type III indicators and compared with commercially available products (powder:liquid = 2.5:1), and all met the requirements.

[0080] II. Opening Hours Test Preparation of paint samples: Weigh the liquid and powder according to the required liquid-to-powder ratio for the experiment. Place the liquid mixture on the disperser and fix it in place. Turn on the disperser and set the speed to (300±20) r / min. Slowly add the powder using a powder shovel, observing as you add it. Do not add it too quickly, as this may cause material buildup. Ensure that all the powder has been added and there is no residue left on the powder shovel. Then, use a paint mixing knife to scrape any remaining powder from the sample cup wall, the disperser, and the rotor into the liquid mixture. Increase the speed to (600±50) r / min and start timing for 5 minutes. After 5 minutes, reduce the speed to (100±10) r / min to defoam and time for 2 minutes. Remove the sample from the machine after 2 minutes. Use a KU viscometer to test the initial viscosity and then test it every 30 minutes.

[0081] III. Anti-alkali test Apply the prepared paint evenly to the concrete slab using a brush (the concrete slab must meet the requirements of 7.5.1 in JC / T547-2017 "Ceramic Tile Adhesives"). Apply two coats, with an interval of more than 8 hours between coats. The dosage for each coat is approximately 0.8 kg / m². 2 24 hours after the second coating is applied, drip water onto the coating and observe the efflorescence after the water dries naturally.

[0082] IV. Crack Resistance Test Apply tile adhesive that meets the C1 requirements of JC / T 547-2017 "Ceramic Tile Adhesives" to the concrete slab. Use a notched scraper to scrape a groove about 3mm deep and let it dry. Use a bristle brush to brush along the groove first, ensuring that the bottom is not missed. Then fill the groove with the material and brush the paint in a direction perpendicular to the groove. After curing, observe the cracking.

[0083] V. Calculation of Total Carbon Emissions of Coatings The total carbon emissions of the coatings in this application are calculated using the following formula: Total carbon emissions of coatings = (Emulsion dosage × Emulsion solid content × Liquid component mass × Emulsion carbon emission factor + Inorganic cementitious material dosage × Powder component mass × Inorganic cementitious material carbon emission factor) / (Liquid component mass + Powder component mass), where: Liquid component by weight: The amount of liquid component added is 1 part by weight; Powder weight parts: The amount of powder to be fed is 2.3-2.5 parts by weight; Emulsion dosage: The mass percentage of the alkali-activated modified bio-based emulsion in the liquid formulation (calculated by substituting a decimal). Emulsion solids content: Solids content of alkali-activated modified bio-based emulsions (calculated as a decimal). Emulsion carbon emission factor: The total amount of greenhouse gases emitted directly or indirectly by a unit mass of emulsion throughout its entire life cycle, expressed as carbon dioxide equivalent (kg CO2e); Inorganic cementitious material dosage: the mass percentage of slag powder in the powder (calculated by substituting decimals); Carbon emission factor of inorganic cementitious materials: The total amount of greenhouse gases emitted directly or indirectly by a unit mass of inorganic cementitious materials throughout their entire life cycle, expressed as carbon dioxide equivalent (kg CO2e).

[0084] Table 1

[0085] Table 2

[0086] In conjunction with Example 1, Comparative Examples 1-6 and Table 1-2, Figure 1-2 As can be seen, in Comparative Example 1, using cement instead of slag powder significantly reduced the elongation at break of the coating, and both low-temperature flexibility and thermal aging low-temperature flexibility failed. This may be because cement hydration forms a high-density CSH gel, but it is brittle and lacks flexibility, and cannot form a good interpenetrating structure with the polymer network like the CASH gel formed by slag powder under alkali activation. This results in an excessively rigid coating with severely insufficient flexibility and low-temperature performance.

[0087] Comparative Example 2 used a cationic bio-based styrene-acrylic emulsion without activator modification instead of an alkali-activated bio-based emulsion. The tensile strength of the coating was lower than the standard, the impermeability failed, and the adhesion strength decreased significantly. This is because without an alkali activator, the slag powder cannot be activated to form CASH gel. At this time, the slag powder exists only as a filler in the coating film. The coating film lacks an inorganic network skeleton and relies solely on polymer emulsion for film formation. The coating film is not dense, resulting in poor impermeability and weak adhesion.

[0088] Comparative Example 3, where an alkaline activator solution was directly mixed with a cationic bio-based styrene-acrylic emulsion in a single step to replace the alkaline activator-modified bio-based emulsion, resulted in a decrease in the elongation at break of the coating, failure to pass low-temperature flexibility tests, and low retention rates of elongation at break after heat aging and alkaline treatment. This is because, on the one hand, the high concentration of negative ions (OH-) in the alkaline activator solution... - SiO3² -(etc.) instantaneous charge neutralization occurs between the latex particles and the cationic emulsion, leading to latex particle demulsification and flocculation, resulting in a significant decrease in film uniformity; on the other hand, ester bonds of latex particles undergo hydrolysis under high pH conditions, and thermal aging and alkali treatment further exacerbate molecular chain breakage; finally, due to the lack of electrostatic adsorption steps, a stable organic-inorganic composite interface cannot be formed between latex particles and alkali activators, resulting in low interfacial bonding strength.

[0089] Comparative Example 4, with a powder-to-liquid ratio adjusted to 2:1 (too little powder), showed that the coating's adhesion strength (untreated, damp substrate) was lower than the standard. Although slightly higher than the standard after alkali treatment, it was still generally low. This is because insufficient powder resulted in a small amount of CASH gel generated from the slag powder, failing to form enough inorganic anchor points in the polymer network, leading to a weak point in the interfacial adhesion between the coating and the substrate. Comparative Example 5, with a powder-to-liquid ratio adjusted to 3:1 (too much powder), showed a decrease in the coating's elongation at break, failure to pass low-temperature flexibility tests, a decrease in adhesion strength, and a low elongation retention rate after aging. This is because excessive powder resulted in an overly thick slurry, a relatively insufficient polymer emulsion, an excessively high proportion of inorganic rigid components in the coating, and a discontinuous polymer flexible network, leading to a comprehensive decline in flexibility, low-temperature performance, adhesion strength, and long-term durability.

[0090] Comparative Example 6 is a commercially available product, using a cement and conventional styrene-acrylic emulsion system. All properties of Comparative Example 6 are lower than those of Example 1, with a shorter open time (excessively high viscosity at 60 minutes), significant efflorescence, poor crack resistance, and significantly higher carbon emissions than this application. This indicates that traditional cement-based polymer waterproof coatings have significant shortcomings in balancing workability, efflorescence resistance, crack resistance, and low carbon emissions. Furthermore, from Figure 1-2 It can be seen that the coating of Comparative Example 6 exhibits obvious efflorescence and cracking, while the coating of Example 1 shows no efflorescence and a significantly reduced degree of cracking, further demonstrating that the solution of this application has significant advantages in resisting efflorescence and cracking.

[0091] Furthermore, the carbon emission factor of cement is 735 kg CO2e / t (data source: GB / T 51366-2019 "Standard for Calculation of Carbon Emissions in Buildings"), the carbon emission factor of conventional styrene-acrylic emulsion is 2.0 kg CO2e / t, while the carbon emission factor of slag powder in this application is 38 kg CO2e / t (data source: Baowu Environmental Technology Slag Powder EPD Report / Carbon Footprint Certification), and the carbon emission factor of alkali-activated modified bio-based emulsion is 1.4 kg CO2e / t (estimated according to ISO14067 standard, based on the conventional styrene-acrylic emulsion of 2.0 kg CO2e / t, calculated by deducting the carbon emission corresponding to 30% bio-based carbon content); the total carbon emission of Example 1 is calculated to be 12.43 kg CO2e / t, while the total carbon emission of the commercially available product in Comparative Example 6 is 106.7 kg CO2e / t. It can be seen that the solution in this application can significantly reduce carbon emissions compared with existing commercially available products.

[0092] Based on Examples 1, 3-4, and Table 1, it can be seen that the tensile strength, elongation at break, and bond strength of the coatings in Examples 3 (using talc powder instead of quartz sand) and 4 (using barium sulfate instead of heavy calcium carbonate) are basically the same as those in Example 1. This indicates that quartz sand and talc powder, as coarse aggregates, and calcium carbonate and barium sulfate, as fillers, can all form a good particle size distribution with slag powder, constructing an effective skeletal support structure in the coating film, while not affecting the interpenetration of the CASH gel and polymer network generated by the alkali-activated reaction. Therefore, the inorganic fillers of this application have good replaceability, and both talc powder and barium sulfate can be used as alternative fillers, which provides a wider range of raw material selection for this application.

[0093] Based on Examples 1, 5-7, and Table 1, it can be seen that the properties of the coatings in Examples 5 (sodium silicate aqueous solution), 6 (sodium carbonate aqueous solution), and 7 (a mixture of sodium silicate and sodium carbonate aqueous solutions) are basically similar to those in Example 1. This indicates that different types of alkaline activators can effectively raise the pH value of the system to above 12, breaking the Si-O and Al-O bonds in the slag glass, dissolving active ions, and condensing them to form CSH and CASH gels. In particular, when sodium silicate and sodium carbonate are used in combination, the dual advantages of the silicate activator's continuous slow release of alkaline components and the carbonate activator's green and low-carbon properties may be utilized, resulting in a slight improvement in coating performance. Therefore, the alkaline activator of this application has good substitutability, and different types of alkaline activators can achieve the technical effects of this application.

[0094] Based on Examples 1, 8-9, and Table 1, it can be seen that the tensile strength, elongation at break, and bond strength of the coatings in Examples 8 (where the monomer feed ratio in S1 deviates from the specified range) and 9 (where all the pre-emulsion and all the initiator solution are mixed at once) are slightly lower than those in Example 1. This indicates that the monomer feed ratio directly affects the particle size distribution and surface charge density of the cationic bio-based styrene-acrylic emulsion, thereby affecting the efficiency and uniformity of subsequent electrostatic adsorption of the alkali activator. In S2, by controlling the nucleation and growth of latex particles through stepwise dropwise addition during the polymerization reaction after emulsion polymerization, a cationic emulsion with uniform particle size and stable surface charge can be obtained, providing a structural basis for the uniform loading of the alkali activator. Deviating from the above process parameters will affect the structural regularity of the latex particles and the distribution of surface active sites, ultimately leading to a decrease in coating performance.

[0095] Based on Examples 1, 10-11, and Table 1, it can be seen that the tensile strength, elongation at break, and bond strength of the coatings in Examples 10 (alkali activator solution concentration of 8%) and 11 (alkali activator solution concentration of 25%) are slightly lower than those in Example 1. This indicates that when the alkali activator concentration is too low (8%), the OH groups in the system... - SiO3 2- Insufficient concentration leads to inadequate activation of slag powder and low CASH gel formation, resulting in decreased coating strength. When the concentration of alkali activator is too high (25%), the high concentration of negative ions and cationic latex particles undergo instantaneous charge neutralization, causing local demulsification and flocculation, reducing film uniformity. At the same time, an excessively high pH environment may exacerbate the hydrolysis of ester bonds in latex particles, leading to damage to the flexibility and long-term durability of the coating.

[0096] Based on Examples 1, 12-14, and Table 1, it can be seen that the coatings of Examples 12 (where the silane coupling agent is added to the composite emulsion all at once instead of by dripping), 13 (where the amount of silane coupling agent is 0.2%), and 14 (where the amount of silane coupling agent is 0.8%) show different strengths. Example 12 exhibits lower tensile and adhesive strength than Example 1, Example 13 shows decreased tensile and adhesive strength, and Example 14 shows decreased elongation at break. This indicates that in step S4, the silane coupling agent, through dripping, slowly crosslinks on the surface of the latex particles, forming a dense and uniform crosslinked network shell. This physically encapsulates the electrostatically adsorbed alkali activator anions within the latex particle shell, effectively preventing desorption and deactivation during storage. Insufficient silane coupling agent (0.2%) results in an incomplete crosslinked network, poor coating effect, and easy desorption of the activator, leading to a decrease in mechanical properties. Excessive silane coupling agent (0.8%) results in an overly thick and dense crosslinked network, reduced latex particle flexibility, and decreased elongation at break of the coating. Therefore, by controlling the amount of silane coupling agent within the above range, the storage stability of the activator and the flexibility of the coating film can be balanced to obtain the best overall performance.

[0097] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application, but such modifications or substitutions are all within the scope of protection of this application.

Claims

1. A polymer water repellent coating, characterized by: The formulation includes powder and liquid, wherein the powder includes slag powder and the liquid includes alkali-activated modified bio-based emulsion; The mass ratio of the powder to the liquid is (2.3-2.5):

1.

2. The polymeric water repellent coating of claim 1, wherein: The powder also includes inorganic fillers and water-reducing agents.

3. The polymeric water repellent coating of claim 1, wherein: The inorganic filler includes at least one of 70-140 mesh quartz sand, 300-400 mesh heavy calcium carbonate, 300-500 mesh talc powder, and 600-800 mesh barium sulfate.

4. The polymeric water repellent coating of claim 1, wherein: The liquid also includes at least one of the following: dispersant, mineral oil defoamer, preservative, blue pigment, and water.

5. The polymeric water repellent coating of claim 1, wherein: The alkali-activated modified bio-based emulsion was prepared by a method comprising the following steps: S1, after mixing bio-based butyl acrylate, styrene, methyl methacrylate, itaconic acid, and methacryloyloxyethyltrimethylammonium chloride, a cationic emulsifier and deionized water are added, and the mixture is emulsified to obtain a pre-emulsion. S2, a portion of the pre-emulsion is mixed with a portion of the initiator solution for emulsion polymerization, and then the remaining portion of the pre-emulsion and the remaining portion of the initiator solution are added dropwise to carry out the polymerization reaction, thereby obtaining a cationic bio-based styrene-acrylic emulsion; S3, the alkaline activator solution is added dropwise to the cationic bio-based styrene-acrylic emulsion, and the mixture is stirred after the addition is complete to obtain a composite emulsion; S4. Add the silane coupling agent dropwise to the composite emulsion, mix, and stir to obtain the final product.

6. The polymeric water repellent coating of claim 5, wherein: In S1, the bio-based butyl acrylate, the styrene, the methyl methacrylate, the itaconic acid, and the methacryloyloxyethyltrimethylammonium chloride are mixed in a mass ratio of 50%-75%: 15%-30%: 10%-25%: 3%-5%: 1%-2.5%. The cationic emulsifier accounts for 2%-3% of the total mass of the monomers.

7. The polymeric water repellent coating of claim 5, wherein: The temperature for emulsion polymerization in S2 is 70-75℃, and the holding time is 25-30 minutes.

8. The polymeric water repellent coating of claim 5, wherein: The alkaline activator in the alkaline activator solution described in S3 includes at least one of sodium hydroxide, sodium silicate, sodium metasilicate, lithium silicate, and sodium carbonate.

9. The polymeric water repellent coating of claim 5, wherein: The concentration of the alkaline activator solution described in S3 is 12%-20%, and the pH value is 11-12; The mass ratio of the alkaline activator solution to the cationic bio-based styrene-acrylic emulsion is 1:(9-10).

10. The polymeric water repellent coating of claim 5, wherein: The mass of the silane coupling agent in S4 accounts for 0.4%-0.6% of the total mass of the composite emulsion.

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