Waterproof tile adhesive composition and preparation method thereof

Abstract

The invention belongs to the technical field of tile adhesives, and relates to a waterproof tile adhesive composition and a preparation method thereof. The waterproof tile adhesive composition is prepared from the following raw material components in parts by weight: 80 to 100 parts of cement-based cementing material, 80 to 100 parts of quartz sand, 2 to 5 parts of hydroxyethyl cellulose, 10 to 16 parts of modified redispersible latex powder, 3 to 6 parts of composite water repellent agent, 1 to 1.5 parts of alkaline water agent, 0.5 to 1 part of mildew preventive and 2 to 5 parts of nano silicon dioxide. By optimizing the raw material ratio, the obtained waterproof ceramic tile adhesive composition has high cohesiveness and waterproofness, does not need to be waterproof, can be directly used, can shorten the construction period, and is suitable for long-term moist or easy water accumulation areas such as household kitchens and bathrooms, balconies, swimming pools, basements, outdoor terraces and the like.

Description

Technical Field

[0001] This invention belongs to the field of tile adhesive technology, and relates to a waterproof tile adhesive composition and its preparation method. Background Technology

[0002] Tile adhesive is a cement-based adhesive made by mixing cement, sand, and functional additives in a certain proportion. It is used to install and fix tiles. It has good adhesion and crack resistance, comes in a variety of attractive colors, and makes tiles more secure and aesthetically pleasing. It has wide applications in modern building decoration.

[0003] With the improvement of people's living standards and the increase in the types and applications of tiles, traditional cement-based adhesives are experiencing a series of problems such as insufficient adhesion and short service life. This is especially true in humid environments such as kitchens, bathrooms, balconies, swimming pools, basements, and outdoor terraces—areas prone to prolonged dampness or water accumulation. Ordinary tile adhesives, due to their poor waterproofing performance, are prone to water seepage, mold, sweating, and detachment, directly posing safety hazards. Furthermore, their application requires a waterproof coating before tile bonding, making the process complex, time-consuming, and costly. While some products improve waterproofing by adding water-repellent agents, these agents generally have limited bonding strength with inorganic materials like cement, resulting in relatively poor stability and a short service life. In long-term humid or water-accumulated environments, the poor waterproofing of the adhesive can lead to swelling and decreased adhesion, further affecting its lifespan. Therefore, developing a tile adhesive with good adhesion, waterproofing, and long service life suitable for humid environments is of great significance. Summary of the Invention

[0004] To address the aforementioned shortcomings, this invention provides a waterproof tile adhesive composition and its preparation method. This waterproof tile adhesive composition combines high-strength adhesion and waterproofing, eliminating the need for additional waterproofing and allowing for direct use. It can shorten the construction period and is suitable for areas that are chronically damp or prone to water accumulation, such as kitchens, bathrooms, balconies, swimming pools, basements, and outdoor terraces. It also has a long service life.

[0005] The purpose of this invention is to provide a waterproof tile adhesive composition, which comprises the following raw material components by weight: 80-100 parts of cement-based cementitious material, 80-100 parts of quartz sand, 2-5 parts of hydroxyethyl cellulose, 10-16 parts of modified redispersible latex powder, 3-6 parts of composite hydrophobic agent, 1-1.5 parts of water-reducing agent, 0.5-1 part of mildew inhibitor, and 2-5 parts of nano silica.

[0006] Preferably, in the above technical solution, the cement-based cementitious material is a mixture of ordinary Portland cement and high-alumina cement in a mass ratio of 100:5-15. This invention adds a small amount of high-alumina cement to the cement-based gel material, which hydrates rapidly, accelerating the hydration process of ordinary Portland cement to form an early skeleton, shortening the setting time, and improving early strength. Simultaneously, the secondary reaction of calcium hydroxide produced during its hydration reduces the total porosity of the system, making the structure denser, improving water resistance, and further effectively combining with silanes in subsequent hydrophobic agents, thereby improving long-term waterproof durability to a certain extent.

[0007] Preferably, in the above technical solution, the quartz sand is composed of 50-80 mesh coarse quartz sand and 81-140 mesh fine quartz sand in a mass ratio of 2-3:3-5. Using quartz sand aggregates with different gradations results in a denser composition, ensuring the bulk density and workability of the composite material.

[0008] Preferably, in the above technical solution, the modified redispersible latex powder is a latex powder modified by copolymerization of fluorinated hydrophobic monomers. The modification method is as follows: 2 / 3 of the total amount of ethylene, vinyl acetate, and butyl acrylate mixed monomers are added to a reaction vessel, along with an appropriate amount of deionized water, emulsifier, and half of the initiator. The mixture is heated to 70-80℃ and reacted for 0.5-1 h. The remaining mixed monomers, initiator, and fluorinated monomers are continuously added dropwise. After the addition is complete, the temperature is raised to 85-90℃ and reacted for 1-2 h. The pH is adjusted to neutral, polyvinyl alcohol is added, and after mixing evenly, the mixture is spray-dried to obtain the final product. In this technical solution, a latex powder modified by copolymerization of fluorinated hydrophobic monomers is used. First, a portion of ethylene, vinyl acetate, and butyl acrylate are polymerized to form a core copolymer. Then, fluorinated monomers are introduced to continue polymerization, forming a shell layer of fluorinated hydrophobic segments on the surface of the pre-polymerized latex particles. This significantly improves the hydrophobicity of the latex film and its adhesion stability to damp substrates.

[0009] Preferably, in the above technical solution, the mass ratio of ethylene, vinyl acetate, and butyl acrylate in the mixed monomers is 40-50:25-35:10-20; the fluorinated monomer is perfluoroalkyl ethyl acrylate or dodecafluoroheptyl methacrylate, and its usage is 4-5% of the total mass of the mixed monomers; the emulsifier is DNS-86 (allyloxynonylphenol polyoxyethylene ether ammonium sulfate), and its usage is 1-2% of the total mass of the mixed monomers; the initiator is ammonium persulfate or potassium persulfate, and its usage is 0.2-0.5% of the total mass of the mixed monomers; the amount of polyvinyl alcohol is 8-10% of the total mass of the modified redispersible latex powder.

[0010] Preferably, in the above technical solution, the composite hydrophobic agent is a composite hydrophobic agent supported on nano-calcium carbonate, and its preparation method is as follows: (1) Dissolve hydrogen-containing silicone oil in isopropanol, add silane coupling agent, add catalytic amount of isopropanol chloroplatinic acid solution, heat to 80-90℃ and react for 3-5 hours to obtain polyfunctional polysiloxane solution. (2) Disperse nano-calcium carbonate in ethanol, sonicate for 0.5-1 h, add an appropriate amount of the polyfunctional polysiloxane solution and zinc stearate from step (1) under high-speed stirring, continue sonication for 0.5-1 h, vacuum dry, pulverize and sieve to obtain a composite hydrophobic agent supported on nano-calcium carbonate. In this invention, the composite hydrophobic agent supported on nano-calcium carbonate is used as the hydrophobic agent. Based on the original organosilicon-higher fatty acid system, a silane coupling agent with epoxy and amino groups is introduced to perform a grafting reaction with hydrogen-containing silicone oil to form a hydrophobic network with multiple coupling structures. Nano-calcium carbonate is added in the later mixing stage to enhance its dispersibility and interfacial bonding in the cement system, and further improve its waterproof stability.

[0011] Preferably, in step (1) of the above technical solution, the mass ratio of the hydrogen-containing silicone oil to isopropanol is 1:1.5-3; the hydrogen content of the hydrogen-containing silicone oil is 0.8-1.2%; the amount of silane coupling agent used is 20-30% of the mass of the hydrogen-containing silicone oil; and the silane coupling agent is a mixture of VTES (vinyltriethoxysilane) and KH-550 (γ-aminopropyltriethoxysilane) in a mass ratio of 2-3:1.

[0012] Preferably, in step (2) of the above technical solution, the particle size of the nano-calcium carbonate is 30-50 nm; the mass ratio of the nano-calcium carbonate, the multifunctional polysiloxane solution and the zinc stearate is 4-6:2:1.

[0013] Preferably, in the above technical solution, the water-reducing agent is a polycarboxylate water-reducing agent; the mildew inhibitor is 1,2-benzisothiazolin-3-one; and the nano-silica is hydrophilic fumed nano-silica with a specific surface area of ​​200-250 m². 2 / g. This technical solution uses hydrophilic fumed nano silica as an auxiliary filler to fill micropores, further improving density and providing a more complete substrate for the hydrophobic agent.

[0014] The present invention also provides a method for preparing the above-mentioned waterproof tile adhesive composition, the method comprising the following steps: S1. According to the raw material ratio, first mix hydroxyethyl cellulose, composite hydrophobic agent, water-reducing agent, mildew inhibitor and half of the fine quartz sand in a high-speed mixer and set aside; S2. Mix the remaining quartz sand, cement-based cementitious materials, and nano-silica evenly according to the raw material ratio; S3. Finally, the materials obtained in S1 and S2, along with the remaining components of the modified redispersible latex powder, are added to a mixer and mixed to obtain a waterproof tile adhesive composition. This invention, through stepwise mixing, achieves more uniform mixing, solving the problem of uneven dispersion of trace components and ensuring the uniformity and stability of the product.

[0015] Advantages compared to existing technologies: This invention optimizes the raw material ratio, using a mixed cement-based material as the gelling material to provide the main gel strength and shorten the setting time; it uses different graded quartz sand as the skeleton to control shrinkage and strength, ensuring bulk density; it uses latex powder modified with fluorinated hydrophobic monomers as a binder to provide a strong polymer network, significantly improving the hydrophobicity of the latex film and its adhesion stability to damp substrates; it uses a composite hydrophobic agent loaded with nano-calcium carbonate as a hydrophobic agent to provide durable hydrophobicity and interfacial strength; and it adds other additives, such as nano-silica to fill micropores to further promote hydration and improve interfacial strength, a water-reducing agent to lower the water-cement ratio and increase density, and a mildew inhibitor to prevent mold growth and extend service life. The resulting waterproof tile adhesive composition not only has excellent adhesion, waterproofness, and durability, but also excellent workability.

[0016] This invention employs a step-by-step mixing process, resulting in more uniform mixing and ensuring product consistency and stability. Simultaneously, the synergistic use of each raw material, working together at the molecular microstructure level, significantly enhances bonding strength, water resistance, and anti-aging properties, while also providing excellent workability and durability, making it suitable for tile laying projects in various harsh environments. Detailed Implementation

[0017] The above-described technical features of the present invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. However, the present invention is not limited to these embodiments, nor are these embodiments limited in any way.

[0018] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the formulations involved in the following examples are all commercially available products that can be purchased from the market.

[0019] The present invention will be further described in detail below with reference to embodiments: Example 1 The preparation method of latex powder modified by copolymerization of fluorinated hydrophobic monomers is as follows: 200g of mixed monomers of ethylene, vinyl acetate, and butyl acrylate (mass ratio of ethylene, vinyl acetate, and butyl acrylate is 46:30:14) are added to a reaction vessel. An appropriate amount of deionized water, 5g of DNS-86, and 0.5g of potassium persulfate are added. The temperature is raised to 75℃ and reacted for 1h. 100g of mixed monomers, 0.5g of initiator, and 14g of perfluoroalkyl ethyl acrylate are added dropwise. After the addition is complete, the temperature is raised to 85℃ and reacted for 2h. The pH is adjusted to neutral, 28g of polyvinyl alcohol is added, and after mixing evenly, it is spray-dried to obtain the final product.

[0020] Example 2 The preparation method of the composite hydrophobic agent supported on nano-calcium carbonate is as follows: (1) Under nitrogen protection, 100g of hydrogen-containing silicone oil (M=8000, H%=1%) was dissolved in 200g of isopropanol, 25g of silane coupling agent (VTES and KH-550 in a mass ratio of 2:1) was added, and a catalytic amount of isopropanol chloroplatinate solution was added dropwise. The temperature was raised to 85℃ and reacted for 4h to obtain a polyfunctional polysiloxane solution. (2) Take 50g of nano calcium carbonate (30-50nm) and disperse it in 100g of ethanol. Sonicate for 40min, add 20g of the multifunctional polysiloxane solution from step (1) and 10g of zinc stearate under high-speed stirring, continue sonication for 1h, vacuum dry at 55℃, pulverize and pass through a 200-mesh sieve to obtain the composite hydrophobic agent supported on nano calcium carbonate.

[0021] Example 3 A waterproof tile adhesive composition comprises, by weight, the following raw material components: 100 parts cement-based cementitious material, 100 parts quartz sand, 4 parts hydroxyethyl cellulose, 15 parts modified redispersible latex powder, 4 parts composite hydrophobic agent, 1.2 parts water-reducing agent, 0.8 parts mildew inhibitor, and 5 parts nano-silica. Among them, The cement-based cementitious material is a mixture of 42.5 grade ordinary Portland cement and CA-70 high-alumina cement in a mass ratio of 100:10.

[0022] Quartz sand is composed of 50-80 mesh coarse quartz sand and 81-140 mesh fine quartz stone in a mass ratio of 2:3.

[0023] The modified redispersible latex powder was prepared by the method of Example 1; the composite hydrophobic agent was prepared by the method of Example 2; the water-reducing agent was a polycarboxylate water-reducing agent; the mildew inhibitor was 1,2-benzisothiazolin-3-one; and the nano-silica was a hydrophilic fumed nano-silica with a specific surface area of ​​200-250 m². 2 / g.

[0024] A method for preparing a waterproof tile adhesive composition includes the following steps: S1. According to the raw material ratio, first mix hydroxyethyl cellulose, composite hydrophobic agent, water-reducing agent, mildew inhibitor and half of the fine quartz sand in a high-speed mixer and set aside; S2. Mix the remaining quartz sand, cement-based cementitious materials, and nano-silica evenly according to the raw material ratio; S3. Finally, add the materials obtained from S1 and S2, along with the remaining components of the modified redispersible latex powder, to a mixer to mix and obtain a waterproof tile adhesive composition.

[0025] Example 4 A waterproof tile adhesive composition comprises, by weight, the following raw material components: 80 parts cement-based cementitious material, 90 parts quartz sand, 5 parts hydroxyethyl cellulose, 10 parts modified redispersible latex powder, 6 parts composite hydrophobic agent, 1 part water-reducing agent, 0.5 parts mildew inhibitor, and 2 parts nano-silica. Among them, The cement-based cementitious material is a mixture of 42.5 grade ordinary Portland cement and CA-70 high-alumina cement in a mass ratio of 100:15.

[0026] Quartz sand is composed of 50-80 mesh coarse quartz sand and 81-140 mesh fine quartz stone in a mass ratio of 3:4.

[0027] The modified redispersible latex powder was prepared by the method of Example 1; the composite hydrophobic agent was prepared by the method of Example 2; the water-reducing agent was a polycarboxylate water-reducing agent; the mildew inhibitor was 1,2-benzisothiazolin-3-one; and the nano-silica was a hydrophilic fumed nano-silica with a specific surface area of ​​200-250 m². 2 / g.

[0028] A method for preparing a waterproof tile adhesive composition includes the following steps: S1. According to the raw material ratio, first mix hydroxyethyl cellulose, composite hydrophobic agent, water-reducing agent, mildew inhibitor and half of the fine quartz sand in a high-speed mixer and set aside; S2. Mix the remaining quartz sand, cement-based cementitious materials, and nano-silica evenly according to the raw material ratio; S3. Finally, add the materials obtained from S1 and S2, along with the remaining components of the modified redispersible latex powder, to a mixer to mix and obtain a waterproof tile adhesive composition.

[0029] Example 5 A waterproof tile adhesive composition comprises, by weight, the following raw material components: 90 parts cement-based cementitious material, 80 parts quartz sand, 2 parts hydroxyethyl cellulose, 16 parts modified redispersible latex powder, 3 parts composite hydrophobic agent, 1.5 parts water-reducing agent, 1 part mildew inhibitor, and 4 parts nano-silica. The cement-based cementitious material is a mixture of 42.5 grade ordinary Portland cement and CA-70 high-alumina cement in a mass ratio of 100:5.

[0030] Quartz sand is composed of 50-80 mesh coarse quartz sand and 81-140 mesh fine quartz stone in a mass ratio of 3:5.

[0031] The modified redispersible latex powder was prepared by the method of Example 1; the composite hydrophobic agent was prepared by the method of Example 2; the water-reducing agent was a polycarboxylate water-reducing agent; the mildew inhibitor was 1,2-benzisothiazolin-3-one; and the nano-silica was a hydrophilic fumed nano-silica with a specific surface area of ​​200-250 m². 2 / g.

[0032] A method for preparing a waterproof tile adhesive composition includes the following steps: S1. According to the raw material ratio, first mix hydroxyethyl cellulose, composite hydrophobic agent, water-reducing agent, mildew inhibitor and half of the fine quartz sand in a high-speed mixer and set aside; S2. Mix the remaining quartz sand, cement-based cementitious materials, and nano-silica evenly according to the raw material ratio; S3. Finally, add the materials obtained from S1 and S2, along with the remaining components of the modified redispersible latex powder, to a mixer to mix and obtain a waterproof tile adhesive composition.

[0033] Comparative Example 1 The preparation method of the composite hydrophobic agent is as follows: (1) Under nitrogen protection, 100g of hydrogen-containing silicone oil (M=8000, H%=1%) was dissolved in 200g of isopropanol, 25g of silane coupling agent (VTES) was added, and a catalytic amount of isopropanol chloroplatinate solution was added dropwise. The temperature was raised to 85℃ and reacted for 4h to obtain a polyfunctional polysiloxane solution. (2) Take 50g of nano calcium carbonate (30-50nm) and disperse it in 100g of ethanol. Sonicate for 40min, add 20g of the polyfunctional polysiloxane solution from step (1) and 10g of zinc stearate under high-speed stirring, continue sonication for 1h, vacuum dry at 55℃, pulverize and pass through a 200-mesh sieve to obtain the composite hydrophobic agent.

[0034] Comparative Example 2 The preparation method of the composite hydrophobic agent is as follows: Under nitrogen protection, 100g of hydrogen-containing silicone oil (M=8000, H%=1%) was dissolved in 200g of isopropanol, 25g of silane coupling agent (VTES and KH-550 in a mass ratio of 2:1) was added, and a catalytic amount of isopropanol chloroplatinate solution was added dropwise. The mixture was heated to 85℃ and reacted for 4h. 150g of zinc stearate was added under high-speed stirring, and the mixture was ultrasonically treated for 1h. The mixture was then vacuum dried at 55℃, pulverized, and passed through a 200-mesh sieve to obtain a composite hydrophobic agent.

[0035] Comparative Example 3 A waterproof tile adhesive composition differs from Example 3 in that the cement-based cementitious material is 42.5 grade ordinary Portland cement, while the rest is the same as in Example 3.

[0036] Comparative Example 4 A waterproof tile adhesive composition differs from Example 3 in that the quartz sand is 50-80 mesh coarse quartz sand, otherwise it is the same as Example 3.

[0037] Comparative Example 5 A waterproof tile adhesive composition differs from Example 3 in that the latex powder is ordinary EVA latex powder, while the rest is the same as in Example 3.

[0038] Comparative Example 6 A waterproof tile adhesive composition differs from Example 3 in that the hydrophobic agent is prepared by the method of Comparative Example 1, while the rest is the same as in Example 3.

[0039] Comparative Example 7 A waterproof tile adhesive composition differs from Example 3 in that the hydrophobic agent is prepared by the method of Comparative Example 2, while the rest is the same as in Example 3.

[0040] Comparative Example 8 A waterproof tile adhesive composition differs from Example 3 in that the hydrophobic agent is a common commercially available silicone hydrophobic agent, otherwise it is the same as Example 3.

[0041] Comparative Example 9 A waterproof tile adhesive composition differs from Example 3 in that it does not contain nano-silica, but is otherwise the same as Example 3.

[0042] Comparative Example 10 A waterproof tile adhesive composition differs from Example 3 in that its preparation method is as follows: cement-based cementitious material, quartz sand, hydroxyethyl cellulose, modified redispersible latex powder, composite hydrophobic agent, water-reducing agent, mildew inhibitor, and nano silica are sequentially added to a mixer and mixed evenly to obtain the final product.

[0043] Test case The waterproof tile adhesive compositions prepared in Examples 3-5 and Comparative Examples 1-10 were used to mold and cure tile adhesive specimens according to the method of JC / T547-2017. The curing condition was room temperature curing for 28 days, and the tensile bond strength of the tile adhesive specimens was tested. The flexural strength, compressive strength, water absorption, and setting time of the tile adhesive specimens were tested according to the method of JC / T984-2011. The curing condition for the tile adhesive specimens was room temperature curing for 28 days. The test results are shown in Tables 1-2.

[0044] Table 1 Test Results of the Example

[0045] Table 2 Comparative Test Results

[0046] As can be seen from the results in Table 1, the waterproof tile adhesive prepared using the formula and method of this invention has performance indicators that far exceed relevant standards. It has good bonding performance, excellent waterproof performance and anti-aging performance, short setting time, and excellent overall performance. It can be used directly in damp places without prior waterproofing, which can shorten the construction period.

[0047] In Comparative Example 3, the absence of high-alumina cement resulted in minimal impact on bonding performance, but its setting time, strength, and impermeability were affected. In Comparative Example 4, the aggregate consisted entirely of coarse quartz sand, leading to slightly lower density and impacting overall performance. Comparative Example 5, using ordinary renewable dispersible latex powder, affected both bonding strength and waterproofing. In Comparative Example 6, the composite hydrophobic agent used only VTES as the silane coupling agent, which negatively impacted the waterproofing of the tile adhesive. In Comparative Example 7, the absence of nano-calcium carbonate in the composite hydrophobic agent significantly affected its overall performance, primarily because it acts as a dispersant for both waterproofing and other materials, thus affecting its stability. In Comparative Example 8, the hydrophobic agent was a commercially available organosilicon hydrophobic agent, resulting in significantly reduced waterproofing and affecting bonding performance. In Comparative Example 9, the absence of nano-silica resulted in lower density, impacting both waterproofing and strength. In Comparative Example 10, the direct mixing of raw materials also affected various properties, mainly due to insufficient uniform mixing.

[0048] In summary, the waterproof tile adhesive composition obtained by this invention through optimizing the raw material ratio not only has excellent adhesion, waterproofness, and anti-aging properties, but also excellent workability and durability. It can be directly used in damp places or areas prone to water accumulation, shortening the construction period, saving costs, and has broad application prospects.

[0049] Finally, it should be emphasized that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A waterproof tile adhesive composition, characterized in that, The waterproof tile adhesive composition comprises the following raw material components by weight: 80-100 parts of cement-based cementitious material, 80-100 parts of quartz sand, 2-5 parts of hydroxyethyl cellulose, 10-16 parts of modified redispersible latex powder, 3-6 parts of composite hydrophobic agent, 1-1.5 parts of water-reducing agent, 0.5-1 part of mildew inhibitor, and 2-5 parts of nano silica.

2. The waterproof tile adhesive composition according to claim 1, characterized in that, The cement-based cementitious material is a mixture of ordinary Portland cement and high-alumina cement in a mass ratio of 100:5-15.

3. The waterproof tile adhesive composition according to claim 1, characterized in that, The quartz sand is composed of 50-80 mesh coarse quartz sand and 81-140 mesh fine quartz stone in a mass ratio of 2-3:3-5.

4. The waterproof tile adhesive composition according to claim 1, characterized in that, The modified redispersible latex powder is a latex powder modified by copolymerization of fluorinated hydrophobic monomers. The modification method is as follows: 2 / 3 of the total amount of ethylene, vinyl acetate and butyl acrylate mixed monomers are added to a reaction vessel, along with an appropriate amount of deionized water, emulsifier and half of the initiator. The temperature is raised to 70-80℃ and reacted for 0.5-1h. The remaining mixed monomers, initiator and fluorinated monomers are continuously added dropwise. After the addition is complete, the temperature is raised to 85-90℃ and reacted for 1-2h. The pH is adjusted to neutral, polyvinyl alcohol is added, and after mixing evenly, it is spray-dried to obtain the final product.

5. The waterproof tile adhesive composition according to claim 4, characterized in that, The mass ratio of ethylene, vinyl acetate, and butyl acrylate in the mixed monomers is 40-50:25-35:10-20; the fluorinated monomer is perfluoroalkyl ethyl acrylate or dodecafluoroheptyl methacrylate, and its usage is 4-5% of the total mass of the mixed monomers; the emulsifier is DNS-86, and its usage is 1-2% of the total mass of the mixed monomers; the initiator is ammonium persulfate or potassium persulfate, and its usage is 0.2-0.5% of the total mass of the mixed monomers; the amount of polyvinyl alcohol is 8-10% of the total mass of the modified redispersible latex powder.

6. The waterproof tile adhesive composition according to claim 1, characterized in that, The composite hydrophobic agent is a composite hydrophobic agent supported on nano-calcium carbonate, and its preparation method is as follows: (1) Dissolve hydrogen-containing silicone oil in isopropanol, add silane coupling agent, add catalytic amount of isopropanol chloroplatinic acid solution, heat to 80-90℃ and react for 3-5 hours to obtain polyfunctional polysiloxane solution. (2) Disperse nano-calcium carbonate in ethanol, sonicate for 0.5-1h, add appropriate amount of multifunctional polysiloxane solution and zinc stearate from step (1) under high speed stirring, continue sonication for 0.5-1h, vacuum dry, pulverize and sieve to obtain composite hydrophobic agent supported on nano-calcium carbonate.

7. The waterproof tile adhesive composition according to claim 6, characterized in that, In step (1), the mass ratio of the hydrogen-containing silicone oil to isopropanol is 1:1.5-3; the hydrogen content of the hydrogen-containing silicone oil is 0.8-1.2%; the amount of silane coupling agent used is 20-30% of the mass of the hydrogen-containing silicone oil; the silane coupling agent is a mixture of VTES and KH-550 in a mass ratio of 2-3:

1.

8. The waterproof tile adhesive composition according to claim 6, characterized in that, In step (2), the particle size of the nano-calcium carbonate is 30-50 nm; the mass ratio of the nano-calcium carbonate, the multifunctional polysiloxane solution and the zinc stearate is 4-6:2:

1.

9. The waterproof tile adhesive composition according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate water-reducing agent; the mildew inhibitor is 1,2-benzisothiazolin-3-one; the nano-silica is hydrophilic fumed nano-silica with a specific surface area of ​​200-250 m². 2 / g.

10. A method for preparing a waterproof tile adhesive composition according to any one of claims 1-9, characterized in that, The preparation method includes the following steps: S1. According to the raw material ratio, first mix hydroxyethyl cellulose, composite hydrophobic agent, water-reducing agent, mildew inhibitor and half of the fine quartz sand in a high-speed mixer and set aside; S2. Mix the remaining quartz sand, cement-based cementitious materials, and nano-silica evenly according to the raw material ratio; S3. Finally, add the materials obtained from S1 and S2, along with the remaining components of the modified redispersible latex powder, to a mixer to mix and obtain a waterproof tile adhesive composition.

Images