Strong-permeability ceramic tile adhesive based on basalt fibers and preparation method of strong-permeability ceramic tile adhesive

Abstract

The invention discloses a strong-permeability ceramic tile adhesive based on basalt fibers and a preparation method thereof. The ceramic tile adhesive is prepared from 40-60 parts of Portland cement, 50-80 parts of quartz sand, 0.5-1.5 parts of basalt fiber, 5-15 parts of redispersible latex powder and 2-5 parts of a water-retaining agent, the surface of the basalt fiber is subjected to phosphorylation treatment; the redispersible latex powder comprises a siloxane modified vinyl acetate-ethylene copolymer and long-chain alkyl grafted polyvinyl alcohol in a mass ratio of (3-4): 1; the siloxane modified vinyl acetate-ethylene copolymer is prepared from a vinyl acetate-ethylene copolymer and an alkenyl siloxane compound in a mass ratio of 100: (3-6) through free radical copolymerization. The invention aims to solve the problems of low bonding strength and easiness in hollowing and falling of the existing ceramic tile adhesive in a high-humidity environment.

Description

Technical Field

[0001] This application relates to the field of building materials, and in particular to a highly penetrating ceramic tile adhesive based on basalt fibers and its preparation method. Background Technology

[0002] Tile adhesive, as a key bonding material used in modern building decoration projects for bonding ceramic tiles, vitrified tiles, slabs and other decorative materials, has the core function of forming a strong, durable adhesive layer between the substrate and the tile with a certain degree of deformation adaptability. This layer resists shear and tensile stresses caused by temperature changes, substrate shrinkage, vibration or external forces, thereby avoiding construction quality problems such as hollowing, cracking or even falling off.

[0003] Currently widely used cement-based tile adhesives typically consist of silicate cement, graded quartz sand, redispersible polymer powder (RDP), cellulose ether, and auxiliary additives. Cement provides the basic inorganic cementitious skeleton, quartz sand acts as aggregate to regulate volume stability and workability, while RDP and cellulose ether together construct an organic-inorganic composite system: cellulose ether ensures full hydration of cement through water retention, while also providing initial viscosity and anti-slip properties; RDP reforms into a film after water evaporation, forming a continuous polymer network that permeates the cement hydration products, significantly improving the flexibility, cohesive strength, and adhesion to low-absorption tiles. This system, through the introduction of an organic polymer film, effectively alleviates the brittleness and cracking defects of traditional pure cement mortar, giving the tile adhesive a certain degree of lateral deformation capability, meeting the basic requirements of the JC / T 547 standard.

[0004] Most mainstream redispersible latex powders are based on vinyl acetate-ethylene copolymer (VAE). While they possess good film-forming properties and flexibility, the vinyl acetate units in their molecular chains have limited polarity, resulting in weak interfacial chemical affinity with dense ceramic tiles and concrete substrates. Furthermore, their strong hydrophilicity leads to a deterioration of the polymer film structure. This makes it difficult for tile adhesives to meet the high durability requirements of harsh environments, especially in high-humidity and water-immersed scenarios such as bathrooms, swimming pools, and building facades. Summary of the Invention

[0005] This application provides a strong-penetration tile adhesive based on basalt fiber and its preparation method, aiming to solve the technical problems of low bonding strength and easy hollowing and detachment of existing tile adhesives in high humidity environments.

[0006] In a first aspect, this application provides a highly penetrating tile adhesive based on basalt fiber, comprising the following components in parts by weight: The composition comprises 40-60 parts silicate cement, 50-80 parts quartz sand, 0.5-1.5 parts basalt fiber, 5-15 parts redispersible latex powder, and 2-5 parts water-retaining agent; the basalt fiber surface is phosphorylated; the redispersible latex powder contains siloxane-modified vinyl acetate-ethylene copolymer and long-chain alkyl-grafted polyvinyl alcohol in a mass ratio of 3-4:1; the siloxane-modified vinyl acetate-ethylene copolymer is prepared by free radical copolymerization of vinyl acetate-ethylene copolymer and alkenyl siloxane compound in a mass ratio of 100:3-6.

[0007] This application utilizes a redispersible latex powder formulated by compounding siloxane-modified vinyl acetate-ethylene copolymer with long-chain alkyl-grafted polyvinyl alcohol. While ensuring the application performance of tile adhesive, it significantly improves its initial and post-immersion tensile bond strength. The siloxane units in the siloxane-modified VAE undergo self-condensation during film formation, introducing a Si-O-Si network into the polymer film. This network effectively prevents moisture penetration into the adhesive layer, greatly improving the adhesion retention rate under harsh conditions such as long-term immersion in water, and alleviating the problem of hollow tiles falling off in damp areas such as bathrooms and exterior walls. Simultaneously, the siloxane groups can chemically bond with Ca(OH)2 in cement hydration products or the concrete substrate, enhancing the interfacial adhesion between the polymer film and the inorganic phase, thereby improving the overall cohesive strength and lateral deformation capacity. Furthermore, the Si-O-Si network imparts excellent water-locking properties to the polymer film, delaying surface moisture evaporation, extending the open time, and facilitating construction adjustments.

[0008] It is important to note that the introduction of siloxanes also enhances the hydrogen bonding between the polymer and water-retaining agents such as cellulose ethers and magnesium aluminum silicate, leading to an increase in the elastic modulus of the wet film. This makes the film prone to rebound during tile pressing, making it difficult to adhere properly. To address this, this application synergistically introduces long-chain alkyl-grafted polyvinyl alcohol. Its flexible alkyl side chains can insert between the polymer and the water-retaining agent, disrupting the over-crosslinked hydrogen bond network and reducing wet elasticity. This makes the adhesive soft and conformable during construction and pressing, preventing rebound and ensuring a smooth tile installation. Furthermore, this flexible segment maintains the flexibility and continuity of the organic phase after curing, without weakening the lateral deformation capability of the final adhesive layer, achieving the dual effect of low elasticity during construction and high toughness after curing.

[0009] It is worth noting that the long-chain alkyl-grafted polyvinyl alcohol prepared by the ring-opening etherification reaction in this application exhibits better stability of its ether bonds compared to amide or ester bonds in the alkaline environment of tile adhesive. It is less prone to hydrolysis and can maintain good elasticity regulation and tensile bond strength after immersion in water. Furthermore, the ether bond network helps maintain the flexibility and continuity of the organic phase, improving the lateral deformation capability of the adhesive layer.

[0010] In any of the above technical solutions, the strength grade of the silicate cement is 42.5 or 52.5.

[0011] In any of the above technical solutions, the quartz sand is graded quartz sand, including 30-100 mesh coarse quartz sand and 100-200 mesh fine quartz sand with a mass ratio of 1:2-3.

[0012] In any of the above technical solutions, the basalt fiber has a diameter of 5-20 μm and a length of 3-10 mm.

[0013] In any of the above technical solutions, the water-retaining agent comprises cellulose ether, magnesium aluminum silicate, and glycerol in a mass ratio of 1:1 to 2:0.5 to 1.

[0014] In any of the above technical solutions, the cellulose ether is selected from any one or more of hydroxypropyl methylcellulose ether, methylcellulose, and hydroxyethylcellulose, preferably hydroxypropyl methylcellulose ether.

[0015] In any of the above technical solutions, the average particle size of the magnesium aluminum silicate is 200-400 mesh.

[0016] The water-retaining agent system used in this application is composed of cellulose ether, magnesium aluminum silicate, and glycerol. The synergistic effect of these three components optimizes the rheological and interfacial behavior of the tile adhesive. Cellulose ether and magnesium aluminum silicate, as conventional water-retaining components, lock in mixing water through molecular chain hydration and lamellar expansion, respectively, ensuring sufficient cement hydration and maintaining system stability and anti-slip properties. While glycerol has limited water-retaining capacity, as a small-molecule polyol with multiple hydroxyl groups, small molecular size, and fast migration rate, it preferentially adsorbs onto the surface of cellulose ether and magnesium aluminum silicate particles in the early stages of mixing, forming local hydrogen bonds without forming a hydrogen bond network. This moderately weakens the strong hydrogen bond association between the water-retaining agent itself and with the modified VAE. Through the synergistic effect of long-chain alkyl-grafted polyvinyl alcohol and glycerol, the initial elastic modulus of the wet paste is effectively reduced. Therefore, during tile pressing, the adhesive layer exhibits good plastic flowability and low resilience, avoiding hollowness or unevenness caused by elastic rebound.

[0017] In any of the above technical solutions, the alkenylsiloxane compound is a (meth)acryloyloxysilane coupling agent and / or a vinylsilane coupling agent.

[0018] In any of the above technical solutions, the (meth)acryloyloxysilane coupling agent is selected from any one or more of 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, and 3-methacryloyloxypropylmethyldiethoxysilane.

[0019] In any of the above technical solutions, the vinyl silane coupling agent is selected from any one or more of vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, and vinyltriacetoxysilane.

[0020] In any of the above technical solutions, the glass transition temperature (Tg) of the vinyl acetate-ethylene copolymer is -15℃ to 0℃.

[0021] In any of the above technical solutions, the preparation method of the siloxane-modified vinyl acetate-ethylene copolymer is as follows: The vinyl acetate-ethylene copolymer emulsion was added to a reaction vessel and heated to 70–85°C. Under nitrogen protection, an alkenyl siloxane compound was mixed with an emulsifier and added dropwise to the reaction system, along with a free radical initiator solution. The dropwise addition time was controlled to be 1–3 hours, and the reaction was maintained at the temperature for 1–2 hours after the addition was completed. The mixture was then cooled to below 40°C, the pH was adjusted to 6.5–8.0, and the mixture was spray-dried to obtain siloxane-modified vinyl acetate-ethylene copolymer latex powder.

[0022] In any of the above technical solutions, the long-chain alkyl-grafted polyvinyl alcohol is prepared by ring-opening etherification of polyvinyl alcohol and long-chain alkyl glycidyl ether in a mass ratio of 3 to 6:1 under alkaline catalysis.

[0023] In any of the above technical solutions, the long-chain alkyl group has 8 to 14 carbon atoms.

[0024] In any of the above technical solutions, the degree of polymerization of the polyvinyl alcohol is 1000-2000, and the degree of alcoholysis is 87%-89%.

[0025] In any of the above technical solutions, the alkaline catalysis uses sodium hydroxide or potassium hydroxide, with an amount of 0.5 to 2.0 wt% of the polyvinyl alcohol mass; the reaction temperature is 55 to 65°C, and the ring-opening etherification reaction time is 3 to 5 hours.

[0026] In any of the above technical solutions, the emulsifier is a nonionic emulsifier and / or anionic emulsifier. For example, the nonionic emulsifier is polyoxyethylene sorbitan fatty acid ester, and the anionic emulsifier is sodium dodecylbenzenesulfonate.

[0027] In any of the above technical solutions, the free radical initiator is ammonium persulfate or potassium persulfate, and its amount is 0.5 to 2.0 wt% of the mass of the vinyl acetate-ethylene copolymer.

[0028] In any of the above technical solutions, the inlet air temperature of the spray drying is 160-180℃, the outlet air temperature is 80-90℃, and the average particle size of the vinyl acetate-ethylene copolymer latex powder is 80-120μm.

[0029] In any of the above technical solutions, the phosphorylation treatment is as follows: basalt fibers are activated in an alkaline solution, then soaked in a phosphoric acid solution with a pH of 2 to 4 at 70 to 90°C for 1 to 2 hours, and then washed and dried to obtain the product.

[0030] In any of the above technical solutions, the alkaline solution is a 5-10 wt% sodium hydroxide aqueous solution, the activation temperature is 40-60℃, and the activation time is 30-60 minutes.

[0031] In tile adhesive systems, water-retaining agents typically work synergistically with redispersible latex powder to construct a continuous, dense organic film structure with water-retaining capabilities, ensuring sufficient hydration, flexible film formation, and excellent adhesion. However, the siloxane-modified vinyl acetate-ethylene copolymer used above, due to the introduction of hydrophobic siloxane segments and the enhanced hydrophobicity of the side chains of long-chain alkyl-grafted polyvinyl alcohol, while improving water resistance or regulating elasticity, simultaneously weakens the compatibility with hydrophilic water-retaining agents (cellulose ethers and magnesium aluminum silicate). This results in an uneven polymer film structure, which in turn affects water retention efficiency, film continuity, and the flexibility of the final cured adhesive layer.

[0032] To address the compatibility degradation issue, this application involves phosphorylation treatment of the basalt fiber surface. The rigid rod-like structure of the basalt fiber can physically penetrate the polymer film-forming region, and the phosphorylated fiber surface is rich in -PO4H2 / –PO3. 2- These functional groups can simultaneously form hydrogen bonds or ion-dipole interactions with both the water-retaining agent and the redispersible latex, thus achieving effective coupling between the two phases. Furthermore, the fibers themselves can form a supporting framework within the polymer film, enhancing the system's crack resistance and deformation resistance. Ultimately, while ensuring proper adhesion during installation, this significantly improves the lateral deformation capacity and long-term bonding durability of the tile adhesive after curing.

[0033] Secondly, this application provides a method for preparing a highly penetrating tile adhesive based on basalt fiber, comprising mixing silicate cement, quartz sand, basalt fiber, redispersible latex powder and water-retaining agent according to the proportions of the tile adhesive described in any of the first aspects.

[0034] In summary, this application has the following beneficial effects: This application achieves synergistic optimization of multiple properties of tile adhesive by employing a redispersible latex powder compounded with siloxane-modified VAE and long-chain alkyl-grafted PVA, a glycerol composite water-retaining system, and phosphorylated basalt fibers. Specifically, the siloxane network significantly improves water resistance and interfacial adhesion, enhancing tensile bonding performance and durability; the long-chain alkyl groups and glycerol jointly regulate the wet elasticity of the adhesive layer, effectively suppressing rebound during construction and ensuring the flatness of tile application; and the phosphorylated basalt fibers bridge and compatibilize the redispersible latex powder and water-retaining agent, improving the crack resistance of the adhesive layer. Ultimately, this application significantly improves the initial and post-immersion tensile bond strength and lateral deformation capacity while ensuring good application open time and adhesion, effectively meeting the application requirements of high-humidity and high-durability scenarios such as bathrooms and exterior walls. Detailed Implementation

[0035] Preparation Example Preparation Example 1-1, Siloxane-modified vinyl acetate-ethylene copolymer, the preparation steps are as follows: 1000g of a 50% solids content vinyl acetate-ethylene copolymer emulsion (MCP Tylac 7505, Tg -10℃) was added to a reactor equipped with a stirrer, condenser, and nitrogen inlet. The mixture was heated to 80℃ and purged with nitrogen for 30 minutes to remove oxygen. 23g of γ-methacryloyloxypropyltrimethoxysilane (KH-570) and 5g of polyoxyethylene sorbitan monooleate (Tween 80) were mixed and added dropwise to the reaction system at a uniform rate over 2 hours. Simultaneously, 5g of ammonium persulfate was dissolved in 50g of deionized water and added at a uniform rate over 30 minutes after the addition began. After the addition was complete, the reaction was maintained at 80℃ for 1.5 hours. The mixture was cooled to 35℃, and the pH was adjusted to 7.0 with ammonia. Subsequently, it was spray-dried at an inlet air temperature of 170℃ and an outlet air temperature of 85℃ to obtain a redispersible latex powder with an average particle size of 100μm.

[0036] Preparation Examples 1-2, siloxane-modified vinyl acetate-ethylene copolymer, the preparation steps are as follows: 1000g of a 50% solids vinyl acetate-ethylene copolymer emulsion (MCP Rovene 7005, Tg -15℃) was added to a reactor equipped with a stirrer, condenser, and nitrogen inlet. The mixture was heated to 80℃ and purged with nitrogen for 30 minutes to remove oxygen. 16g of vinyltriethoxysilane was mixed with 4g of sodium dodecylbenzenesulfonate and added dropwise to the reaction system at a uniform rate over 2.5 hours. Simultaneously, 4g of potassium persulfate was dissolved in 30g of deionized water and added at a uniform rate over 30 minutes after the addition began. After the addition was complete, the reaction was maintained at 72℃ for 2 hours. The mixture was cooled to 35℃, and the pH was adjusted to 7.0 with ammonia. The mixture was then spray-dried at an inlet air temperature of 165℃ and an outlet air temperature of 80℃ to obtain a redispersible latex powder with an average particle size of 85μm.

[0037] Preparation Examples 1-3, siloxane-modified vinyl acetate-ethylene copolymer, the preparation steps are as follows: 1000g of a 50% solids content vinyl acetate-ethylene copolymer emulsion (MCP Rovene 7005, Tg 0℃) was added to a reactor equipped with a stirrer, condenser, and nitrogen inlet. The mixture was heated to 83℃ and nitrogen was purged for 30 minutes to remove oxygen. 30g of γ-methacryloyloxypropyltriethoxysilane was mixed with 6g of polyoxyethylene sorbitan monooleate (Tween 80) and added dropwise to the reaction system at a uniform rate over 2 hours. Simultaneously, 8g of ammonium persulfate was dissolved in 65g of deionized water and added at a uniform rate over 30 minutes after the addition began. After the addition was complete, the reaction was maintained at 83℃ for 1.2 hours. The mixture was cooled to 35℃, and the pH was adjusted to 7.5 with ammonia. The mixture was then spray-dried at an inlet air temperature of 175℃ and an outlet air temperature of 85℃ to obtain a redispersible latex powder with an average particle size of 110μm.

[0038] Preparation Example 2-1: Long-chain alkyl-grafted polyvinyl alcohol was prepared according to the following steps: 350g of polyvinyl alcohol (PVA-1788) with a degree of polymerization of 1700 and a degree of hydrolysis of 88% was added to a mixed solvent consisting of 420g of deionized water and 280g of anhydrous ethanol. The solution was stirred at 90°C for 2 hours to form a homogeneous and transparent solution. The temperature was lowered to 60°C, and nitrogen gas was purged for 15 minutes. 3.5g of sodium hydroxide was added, and the mixture was stirred and activated for 10 minutes. 100g of dodecyl glycidyl ether was added dropwise to the reaction system at a uniform rate over 40 minutes. After the addition was complete, the reaction was continued at 60°C for 4 hours. After the reaction was completed, the solution was cooled to 40°C, neutralized with glacial acetic acid to pH 7.0, and then poured into 500mL of acetone to precipitate. The precipitate was filtered, washed three times with acetone, and dried under vacuum at 40°C for 24 hours to obtain long-chain alkyl-grafted polyvinyl alcohol powder.

[0039] Preparation Example 2-2: Long-chain alkyl-grafted polyvinyl alcohol was prepared according to the following steps: 300g of polyvinyl alcohol (PVA-1788) with a degree of polymerization of 1700 and a degree of hydrolysis of 88% was added to a mixed solvent consisting of 360g of deionized water and 240g of anhydrous ethanol. The solution was stirred at 90°C for 2 hours to form a homogeneous, transparent solution. The solution was then cooled to 55°C and purged with nitrogen for 15 minutes. 3.0g of sodium hydroxide was added and the mixture was stirred to activate the reaction for 10 minutes. 100g of octyl glycidyl ether was added dropwise to the reaction system at a uniform rate over 40 minutes. After the addition was complete, the reaction was continued at 55°C for 3.5 hours. After the reaction was completed, the solution was cooled to 40°C and neutralized with glacial acetic acid to pH 7.0. The precipitate was then poured into 500mL of acetone, filtered, and the solid was washed three times with acetone and dried under vacuum at 40°C for 24 hours to obtain long-chain alkyl-grafted polyvinyl alcohol powder.

[0040] Preparation Example 2-3: Long-chain alkyl-grafted polyvinyl alcohol was prepared according to the following steps: 550g of polyvinyl alcohol (PVA-1088) with a degree of polymerization of 1000 and a degree of alcoholysis of 88% was added to a mixed solvent consisting of 750g of deionized water and 450g of anhydrous ethanol. The solution was stirred at 90°C for 3 hours to form a homogeneous, transparent solution. The solution was then cooled to 60°C and purged with nitrogen for 20 minutes. 10g of sodium hydroxide was added and the mixture was stirred to activate the reaction for 12 minutes. 100g of tetradecyl glycidyl ether was added dropwise to the reaction system at a uniform rate over 40 minutes. After the addition was complete, the reaction was continued at 60°C for 5 hours. After the reaction was completed, the solution was cooled to 40°C and neutralized to pH 7.0 with glacial acetic acid. The precipitate was then poured into 600mL of acetone, filtered, and the solid was washed three times with acetone and dried under vacuum at 45°C for 20 hours to obtain long-chain alkyl-grafted polyvinyl alcohol powder.

[0041] Preparation Example 3-1, Phosphorylated basalt fibers, were prepared according to the following operation: 100g of basalt short-cut fibers with a diameter of 13μm and a length of 6mm were added to 500mL of 7.5wt% sodium hydroxide aqueous solution and stirred at 50℃ for 45 minutes to remove surface impurities and activate the fibers. After filtration, the fibers were washed with deionized water until neutral. The activated fibers were transferred to 900mL of phosphoric acid solution (pH=3.0, prepared from 85% H3PO4 and deionized water) and immersed in a constant temperature water bath at 80℃ for 1.5 hours with continuous stirring. After the reaction was completed, the fibers were filtered and washed repeatedly with deionized water at 60℃ until the pH of the washings was ≥6.6. The wet fibers were dried at 100℃ for 3 hours and then cooled to obtain phosphorylated basalt fibers.

[0042] Preparation Example 3-2, Phosphorylated basalt fibers, were prepared according to the following operation: 100g of basalt short-cut fibers with a diameter of 13μm and a length of 6mm were added to 500mL of 5.2wt% sodium hydroxide aqueous solution and stirred at 45℃ for 30 minutes to remove surface impurities and activate the fibers. After filtration, the fibers were washed with deionized water until neutral. The activated fibers were transferred to 750mL of phosphoric acid solution (pH=3.5, prepared from 85% H3PO4 and deionized water) and immersed in a constant temperature water bath at 72℃ for 1.2 hours with continuous stirring. After the reaction was completed, the fibers were filtered and washed repeatedly with deionized water at 60℃ until the pH of the washings was ≥6.0. The wet fibers were dried at 95℃ for 4 hours and then cooled to obtain phosphorylated basalt fibers.

[0043] Preparation Example 3-3, Phosphorylated basalt fibers, were prepared according to the following operation: 100g of basalt short-cut fibers with a diameter of 18μm and a length of 9mm were added to 600mL of 9.5wt% sodium hydroxide aqueous solution and stirred at 50℃ for 45 minutes to remove surface impurities and activate the fibers. After filtration, the fibers were washed with deionized water until neutral. The activated fibers were transferred to 1000mL of phosphoric acid solution (pH=2.3, prepared from 85% H3PO4 and deionized water) and immersed in a constant temperature water bath at 85℃ for 2 hours with continuous stirring. After the reaction was completed, the fibers were filtered and washed repeatedly with deionized water at 60℃ until the pH of the washings was ≥6.0. The wet fibers were dried at 100℃ for 3 hours and then cooled to obtain phosphorylated basalt fibers.

[0044] Example Example 1: A highly penetrating tile adhesive based on basalt fiber is prepared according to the following process steps: Weigh out 500g of silicate cement (Conch P·O 42.5) with a strength grade of 42.5, 650g of graded quartz sand (including 200g of 50-60 mesh coarse sand and 450g of 120-150 mesh fine sand), 10g of phosphorylated basalt fiber (Preparation Example 3-1), 100g of redispersible latex powder (containing 75g of siloxane-modified vinyl acetate-ethylene copolymer from Preparation Example 1-1 and 25g of long-chain alkyl-grafted polyvinyl alcohol from Preparation Example 2-1), and 37.5g of water-retaining agent (containing 15g of hydroxypropyl methylcellulose ether (Yidahehao YD1920), 15g of magnesium aluminum silicate (Pinying New Materials PYY-SC), and 7.5g of glycerin). Add all the above components to a laboratory double cone mixer and mix at 30 rpm for 20 minutes at room temperature and pressure to obtain a uniform dry powder tile adhesive.

[0045] Example 2: A highly penetrating tile adhesive based on basalt fiber is prepared according to the following process steps: Weigh out 520g of silicate cement (Conch P·O 42.5) with a strength grade of 42.5, 500g of graded quartz sand (including 125g of 50-60 mesh coarse sand and 375g of 120-150 mesh fine sand), 6g of phosphorylated basalt fiber (Preparation Example 3-2), 60g of redispersible latex powder (containing 45g of siloxane-modified vinyl acetate-ethylene copolymer from Preparation Example 1-2 and 15g of long-chain alkyl-grafted polyvinyl alcohol from Preparation Example 2-2), and 24g of water-retaining agent (containing 6g of hydroxypropyl methylcellulose ether (Yidahehao YD1920), 12g of magnesium aluminum silicate (Pinying New Materials PYY-SC), and 6g of glycerin). Add all the above components to a laboratory double cone mixer and mix at 30 rpm for 20 minutes at room temperature and pressure to obtain a uniform dry powder tile adhesive.

[0046] Example 3: A highly penetrating tile adhesive based on basalt fiber is prepared according to the following process steps: Weigh out 600g of silicate cement (Conch P·O 42.5) with a strength grade of 42.5, 800g of graded quartz sand (including 200g of 50-60 mesh coarse sand and 600g of 120-150 mesh fine sand), 15g of phosphorylated basalt fiber (Preparation Example 3-3), 150g of redispersible latex powder (containing 120g of siloxane-modified vinyl acetate-ethylene copolymer from Preparation Example 1-3 and 30g of long-chain alkyl-grafted polyvinyl alcohol from Preparation Example 2-3), and 50g of water-retaining agent (containing 20g of hydroxypropyl methylcellulose ether (Yidahehao YD1920), 20g of magnesium aluminum silicate (Pinying New Materials PYY-SC), and 10g of glycerin). Add all the above components to a laboratory double cone mixer and mix at 30 rpm for 20 minutes at room temperature and pressure to obtain a uniform dry powder tile adhesive.

[0047] Example 4, a highly penetrating tile adhesive based on basalt fiber, differs from Example 1 in that an equal amount of hydroxypropyl methylcellulose ether (Yidahehao YD1920) is used instead of glycerin in the water-retaining agent.

[0048] Example 5, a highly penetrating tile adhesive based on basalt fiber, differs from Example 1 in that an equal amount of glycerol is used instead of hydroxypropyl methylcellulose ether (Yidahehao YD1920) in the water-retaining agent.

[0049] Example 6, a highly penetrating tile adhesive based on basalt fiber, differs from Example 1 in that an equal amount of unmodified basalt short-cut fibers (13 μm in diameter and 6 mm in length) replaces the phosphorylated basalt fibers of Preparation Example 3-1.

[0050] Comparative Example Comparative Example 1, a highly penetrating tile adhesive based on basalt fiber, differs from Example 1 in that an equal amount of the siloxane-modified vinyl acetate-ethylene copolymer of Preparation Example 1-1 is used to replace the long-chain alkyl-grafted polyvinyl alcohol of Preparation Example 2-1 in the redispersible latex powder.

[0051] Comparative Example 2, a highly penetrating tile adhesive based on basalt fiber, differs from Example 1 in that an equal amount of long-chain alkyl-grafted polyvinyl alcohol from Preparation Example 2-1 is used to replace the siloxane-modified vinyl acetate-ethylene copolymer from Preparation Example 1-1 in the redispersible latex powder.

[0052] Comparative Example 3, a highly penetrating tile adhesive based on basalt fiber, differs from Example 1 in that an equal amount of vinyl acetate-ethylene copolymer powder (MCP Tylac 7505, Tg -10℃) is used to replace the siloxane-modified vinyl acetate-ethylene copolymer of Preparation Example 1-1 in the redispersible latex powder.

[0053] Comparative Example 4, a highly penetrating tile adhesive based on basalt fiber, differs from Example 1 in that an equal amount of polyvinyl alcohol (PVA-1788) is used to replace the long-chain alkyl-grafted polyvinyl alcohol in Preparation Example 2-1 in the redispersible latex powder.

[0054] Performance testing Test 1: Tensile bonding and water immersion tensile bonding performance test In accordance with the relevant provisions of Section 7.11 "Determination of Tensile Bond Strength" in JC / T 547–2017 "Adhesives for Ceramic Wall and Floor Tiles", the tensile bond strength test was conducted by immersion in water.

[0055] 1. Test subjects All examples and comparative examples used dry powdered tile adhesive; Ala-type extruded ceramic tiles (water absorption rate 0.1%~0.5%) conforming to Appendix A of GB / T 4100-2015, with dimensions of (50±1) mm × (50±1) mm and a thickness of (5±2) mm; and concrete slabs (400mm×400mm×40mm) conforming to Appendix A of JC / T 547-2017, with a moisture content <3% and a surface water absorption of 0.5~1.5cm² over 4 hours. 3 .

[0056] 2. Sample preparation Add tile adhesive and deionized water to a planetary cement mortar mixer at a water-to-powder ratio of 0.3, and mix according to step 7.4.1: add water first, then sprinkle dry powder, mix for 30 seconds, scrape the sides for 1 minute, mix again for 1 minute, allow to mature for 15 minutes, and then mix for an additional 15 seconds. Apply a thin layer of adhesive (approximately 1 mm) to the concrete slab using a straight-edged trowel, then use a 6 mm × 6 mm (center-to-center distance 12 mm) notched trowel at a 60° angle to the slab surface to form a uniform adhesive layer. Immediately align and adhere the ceramic tiles, placing a (2.00 ± 0.015) kg weight on each tile for 30 seconds to ensure complete adhesion (2500 mm²). 2 Ten specimens were prepared for each group and cured according to different test items.

[0057] 3. Testing Procedures (1) Initial tensile bond strength The specimens were cured for 27 days under standard conditions (temperature 23±2℃, relative humidity 50±5%, wind speed <0.2m / s). A (50±1)mm × (50±1)mm metal pull-out head was adhered to the ceramic tile surface using epoxy adhesive, and standard curing continued for another 24 hours. A tensile testing machine with 1% accuracy was used to apply a tensile force at a rate of (250±50) N / s until failure, and the maximum load L (N) was recorded. The strength was calculated using the formula As=L / A (A=2500mm). 2(Accurate to 0.1 MPa); discard data exceeding ±20% of the average, retain ≥5 valid data points and average them, while recording the damage mode.

[0058] (2) Tensile bond strength after immersion in water After standard curing for 7 days, the specimens were immersed in deionized water at (23±2)℃ for 20 days. The specimens were then removed, dried, and the pull-out heads were attached. After standard curing for 7 hours, the specimens were immersed in water at the same temperature for 17 hours. Immediately after removal, the specimens were tested at the loading rate described above, and the strength was calculated and the failure mode was recorded.

[0059] Experiment 2: Flexibility (lateral deformation) test The test was conducted in accordance with the relevant provisions of section 7.12 "Determination of transverse deformation" in JC / T 547–2017 "Ceramic Tile Adhesives".

[0060] 1. Test subjects Tile adhesive prepared in all embodiments and comparative examples; polyethylene film with a thickness ≥ 0.15 mm; mold A (280 mm × 45 mm × 5 mm) and mold B (300 mm × 45 mm × 3 mm) meeting the requirements.

[0061] 2. Sample preparation The polyethylene film was laid flat and fixed on a rigid support. Mold A was pressed tightly onto the film, and the well-mixed tile adhesive was filled in and leveled. Mold A was fixed on the slab table specified in JC / T 958-2005 and vibrated 70 times. Mold A was then removed. The inner wall of mold B was coated with release agent and placed in the center of the specimen. A (10.0±0.1) kg pressure block (area 290mm×45mm) was placed on top, and the overflowing adhesive was scraped off. The pressure block was removed after 1 hour, and mold B was removed after 48 hours to prepare 6 specimens. The specimens were placed in a sealed plastic container (volume 26±5L) and cured at (23±2)℃ for 12 days, and then transferred to standard conditions for curing for 14 days.

[0062] 3. Testing Procedures Remove the polyethylene film from the specimen surface. Measure the thickness at three points (midpoint and 50±1mm from each end) using a vernier caliper with an accuracy of 0.01mm. The deviation should be within (3.0±0.1)mm, and the average value should be taken. Place the specimen on the test stand (center distance between the two cylindrical supports 200±1mm). Apply a transverse load to the midpoint of the specimen using a testing machine at a rate of 2mm / min until failure. Record the maximum deformation value (mm) of the specimen from the starting point to failure, accurate to 0.1mm, and take the average value of three valid specimens.

[0063] Test 3: Wet elasticity (compression resilience) test 1. Test subjects Tile adhesive prepared in all embodiments and comparative examples; horizontal glass plate (500mm×500mm×10mm); 50mm×50mm flat metal pressure plate; 0.01mm vernier caliper; (1.0±0.1)kg standard weight.

[0064] 2. Sample preparation Prepare the adhesive slurry (water-to-powder ratio as before) and let it stand for 10 minutes; take about 50g of slurry and pile it in the center of a horizontal glass plate, naturally forming a hemispherical pile (initial height H0≈30mm).

[0065] 3. Testing Procedures Press the grout vertically down with a flat metal plate (50mm×50mm) with a force of (1.0±0.1)kg until it reaches a height of 10mm, and hold for 10s. Quickly remove the plate and use calipers to measure the grout rebound height ΔH (mm) within 10 seconds. The smaller ΔH is, the lower the wet elasticity and the better the adhesion. Repeat each group 5 times and take the average value.

[0066] Table 1 Performance Test Results

[0067] Analysis of experimental results: Compared to Example 1, Example 4 showed poorer performance in terms of wet rebound height, indicating that glycerol plays a key role in reducing wet elasticity. This may be because glycerol, as a small-molecule polyol, preferentially adsorbs onto the surfaces of HPMC and magnesium aluminum silicate, weakening the strong hydrogen bond network between them and the modified VAE, thereby reducing the initial elastic modulus of the slurry. Without glycerol, the hydrogen bond network formed between the redispersible latex powder and the water-retaining agent becomes too strong, leading to a significant increase in rebound during pressing.

[0068] Example 5 showed a significant decrease in initial strength, immersion strength, and lateral deformation. This may be because glycerol's water-retention capacity is far lower than that of cellulose ether, the core water-retention component ensuring film continuity and flexibility. HPMC not only provides the main water-retention capacity to ensure sufficient cement hydration but also forms an interpenetrating network with the polymer film; the absence of HPMC leads to insufficient hydration and discontinuous organic film, resulting in deterioration of overall mechanical properties.

[0069] Example 6 showed a significant decrease in water retention rate and lateral deformation, indicating that phosphorylation treatment is crucial for improving compatibility and crack resistance. This may be because the unmodified fibers cannot improve the compatibility between the water-retaining agent and RDP, resulting in a non-uniform polymer membrane structure and a decline in initial water retention and subsequent impermeability. Furthermore, the fibers and polymer membrane cannot form an effective interface, failing to create a rigid support structure, thus weakening durability and deformability.

[0070] Compared to Example 1, Comparative Example 1 showed a significant deterioration in wet rebound height. Although the initial strength was slightly higher, it rebounded easily during application and was difficult to apply flat. This indicates that long-chain alkyl-grafted PVA is indispensable for controlling wet rheological behavior. The reason may be that the hydrogen bonds between the siloxane-modified VAE and HPMC are too strong, resulting in excessively high elasticity of the wet film; the lack of flexible alkyl side chains disrupts the network, leading to an overly hard adhesive layer after curing. Comparative Example 2 showed a significant decrease in water immersion strength, retention rate, and lateral deformation capacity, indicating that the siloxane network is key to achieving high water resistance, flexibility, and interfacial adhesion of the adhesive layer, and long-chain alkyl-grafted polyvinyl alcohol cannot achieve the same effect. Comparative Example 3 showed significant deterioration in initial adhesive strength, water immersion adhesive strength, retention rate, and lateral deformation capacity, verifying that the unmodified VAE system is unable to meet the requirements of high humidity and water immersion environments. The reason may be that the ethylene segment of ordinary VAE is the core of the highly flexible organic membrane, but its vinyl acetate segment is easily hydrolyzed and cannot form a Si-O-Si network to block water penetration, leading to rapid degradation of the polymer membrane in water. The comparative example shows an extremely high 4ΔH and a significantly reduced lateral deformation, indicating that ordinary PVA not only fails to reduce elasticity during wet application but also, due to its strong hydrophilicity, intensifies the hydrogen bond network, resulting in increased resilience and decreased film toughness.

[0071] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A high-penetration tile adhesive based on basalt fiber, characterized in that, The components include the following parts by weight: The composition comprises 40-60 parts silicate cement, 50-80 parts quartz sand, 0.5-1.5 parts basalt fiber, 5-15 parts redispersible latex powder, and 2-5 parts water-retaining agent; the basalt fiber surface is phosphorylated; the redispersible latex powder contains siloxane-modified vinyl acetate-ethylene copolymer and long-chain alkyl-grafted polyvinyl alcohol in a mass ratio of 3-4:1; the siloxane-modified vinyl acetate-ethylene copolymer is prepared by free radical copolymerization of vinyl acetate-ethylene copolymer and alkenyl siloxane compound in a mass ratio of 100:3-6.

2. The tile adhesive according to claim 1, characterized in that, The water-retaining agent comprises cellulose ether, magnesium aluminum silicate, and glycerol in a mass ratio of 1:1 to 2:0.5 to 1.

3. The tile adhesive according to claim 1, characterized in that, The alkenylsiloxane compound is a (meth)acryloyloxysilane coupling agent and / or a vinylsilane coupling agent.

4. The tile adhesive according to claim 1, characterized in that, The glass transition temperature of the vinyl acetate-ethylene copolymer is -15℃ to 0℃.

5. The tile adhesive according to claim 1, characterized in that, The preparation method of the siloxane-modified vinyl acetate-ethylene copolymer is as follows: The vinyl acetate-ethylene copolymer emulsion was added to a reaction vessel and heated to 70–85°C. Under nitrogen protection, an alkenyl siloxane compound was mixed with an emulsifier and added dropwise to the reaction system, along with a free radical initiator solution. The dropwise addition time was controlled to be 1–3 hours, and the reaction was maintained at the temperature for 1–2 hours after the addition was completed. The mixture was then cooled to below 40°C, the pH was adjusted to 6.5–8.0, and the mixture was spray-dried to obtain siloxane-modified vinyl acetate-ethylene copolymer latex powder.

6. The tile adhesive according to claim 1, characterized in that, The long-chain alkyl-grafted polyvinyl alcohol is prepared by ring-opening etherification of polyvinyl alcohol and long-chain alkyl glycidyl ether in a mass ratio of 3 to 6:1 under alkaline catalysis.

7. The tile adhesive according to claim 6, characterized in that, The long-chain alkyl group has 8 to 14 carbon atoms.

8. The tile adhesive according to claim 6, characterized in that, The degree of polymerization of the polyvinyl alcohol is 1000-2000, and the degree of alcoholysis is 87%-89%.

9. The tile adhesive according to claim 1, characterized in that, The phosphorylation treatment is as follows: basalt fibers are activated in an alkaline solution, then soaked in a phosphoric acid solution with a pH of 2 to 4 at 70 to 90°C for 1 to 2 hours, followed by washing and drying.

10. A method for preparing a highly penetrating tile adhesive based on basalt fiber, characterized in that, include: The tile adhesive is prepared by mixing silicate cement, quartz sand, basalt fiber, redispersible latex powder and water-retaining agent according to the proportions described in any one of claims 1 to 9.

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