A nano-silica sol composite interface treatment agent with controllable particle size and a preparation method thereof

Abstract

The application discloses a nano-silica sol composite interface treating agent with controllable particle size and a preparation method thereof, which is composed of the following components in parts by weight: active nano-silica sol 15-40 parts, epoxy resin / polyurethane-based reactive polymer emulsion 45-70 parts, emulsifier 1-5 parts, curing agent 2-8 parts, dispersing agent 0.5-3 parts and water 5-15 parts. The application realizes efficient compatibility of inorganic nano-silica sol and organic polymer emulsion, and the prepared treating agent has high adhesive strength, excellent water resistance and weather resistance and storage stability; the preparation process is mild, controllable, green and environment-friendly, is suitable for industrialized mass production, and can be widely applied in the fields of building, coating, composite material, electronic packaging and the like.

Description

Technical Field

[0001] This invention belongs to the field of interface treatment materials technology, and particularly relates to a nano-silica sol composite interface treatment agent with controllable particle size and its preparation method. Background Technology

[0002] Interface treatment agents are key auxiliary materials for improving the interfacial bonding performance between two or more different materials, enhancing the overall mechanical strength, water resistance, corrosion resistance, and adhesion stability of composite materials. They are widely used in construction, coatings, composite materials, electronic packaging, and many other fields. Currently, most interface treatment agents on the market are based on single polymer emulsions or ordinary silica sols, which have significant drawbacks: single polymer emulsion interface treatment agents have poor weather resistance and high-temperature resistance, and insufficient adhesion strength to inorganic substrates (such as glass, metal, and ceramics); ordinary silica sols have uneven particle size distribution, low activity, and a silanol content of <3.0 mmol / g, resulting in poor compatibility with organic polymer emulsions. After compounding, they are prone to delamination and agglomeration, leading to unstable performance of the interface treatment agent and failing to meet the stringent requirements for interfacial bonding performance in high-end fields.

[0003] The sol-gel method is a common method for preparing nano-silicon materials, with advantages such as simple process, mild reaction conditions, and easy control of product particle size. The sol-gel reaction with tetraethyl orthosilicate (TEOS) as a precursor is mature and controllable. However, the nano-silica sol prepared by this method often has problems such as a wide particle size distribution range and insufficient content of surface active groups, making it difficult to achieve efficient composite with organic polymer emulsions such as epoxy resin and polyurethane. At the same time, the existing technology has not yet formed a preparation process that can precisely control the particle size of nano-silica sol (10~50nm) and achieve synergistic effects between silica sol and epoxy resin / polyurethane-based emulsions by optimizing the composite ratio, emulsifier and curing agent type, which limits the efficient application of nano-silica sol in the field of interface treatment agents.

[0004] Therefore, developing a nano-silica sol with precise and controllable particle size and high activity, optimizing its composite process with epoxy resin / polyurethane-based reactive polymer emulsions, verifying the action mechanism of each component and process parameter through comparative experiments, clarifying performance testing standards, and preparing a composite interface treatment agent with excellent interfacial bonding performance, good stability, and wide applicability have become urgent technical problems to be solved in this field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a nano-silica sol composite interface treatment agent with controllable particle size and its preparation method. The prepared treatment agent has high bonding strength, excellent water and weather resistance and stable storage.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A nano-silica sol composite interface treatment agent with controllable particle size is composed of the following components in parts by weight: 15-40 parts of active nano-silica sol, 45-70 parts of epoxy resin / polyurethane-based reactive polymer emulsion, 1-5 parts of emulsifier, 2-8 parts of curing agent, 0.5-3 parts of dispersant, and 5-15 parts of water. The active nano-silica sol was prepared using tetraethyl orthosilicate as a precursor via a sol-gel method, with a particle size controlled at 10–50 nm, a surface silanol content of 3.5–5.2 mmol / g, and a particle size variation coefficient ≤15%. The epoxy resin / polyurethane-based reactive polymer emulsion is a compound system of epoxy resin emulsion and polyurethane emulsion, with a compound mass ratio of (1~3):1.

[0007] Furthermore, in the epoxy resin / polyurethane-based reactive polymer emulsion, the epoxy value of the epoxy resin emulsion is 0.1~0.5 eq / 100g, and the solid content is 40~60wt%; the NCO group content of the polyurethane emulsion is 1~5wt%, and the solid content is 35~55wt%.

[0008] Furthermore, the emulsifier is selected from one or a mixture of two or more of sodium dodecylbenzenesulfonate, fatty alcohol polyoxyethylene ether, and nonylphenol polyoxyethylene ether.

[0009] Furthermore, the emulsifier is a mixture of anionic and nonionic emulsifiers in a mass ratio of (1~2):1.

[0010] Furthermore, the curing agent is selected from one or a mixture of two or more of aliphatic polyamines, aromatic polyamines, and polyamide curing agents.

[0011] Furthermore, the dispersant is selected from sodium polycarboxylate and polyacrylate dispersants.

[0012] This invention also provides a method for preparing the nano-silica sol composite interface treatment agent with controllable particle size, comprising the following steps: (1) Under stirring, the active nano silica sol is added to the polymer emulsion compounding system and the stirring process continues; the polymer emulsion compounding system is composed of epoxy resin / polyurethane-based reactive polymer emulsion and dispersant; (2) Add emulsifier, adjust the pH of the system to 6-8, and continue stirring; (3) Add curing agent, continue stirring, then heat up to mature, cool and filter to obtain the nano-silica sol composite interface treatment agent with controllable particle size.

[0013] Furthermore, the preparation method of the active nano-silica sol is as follows: (1) Tetraethyl orthosilicate is added dropwise to the mixed solvent system at a rate of 1-3 mL / min. During the dropwise addition, the stirring rate is maintained at 300-600 r / min. After the dropwise addition is completed, the temperature is raised to 30-50℃ and the reaction is carried out under constant temperature stirring to obtain a silica sol precursor solution. The mixed solvent system is an ethanol aqueous solution with a pH of 2-4. (2) Adjust the pH of the silica sol precursor solution to 7-9, and continue to stir the reaction at a constant temperature for 1-3 hours to form a nano silica sol system; (3) The nano silica sol system is subjected to vacuum distillation until the solid content of the system is 20~40wt% to obtain active nano silica sol.

[0014] Furthermore, the preparation method of the polymer emulsion compound system is as follows: epoxy resin emulsion and polyurethane emulsion are added to a reaction vessel at a compound mass ratio of (1~3):1, then a dispersant is added, and the mixture is stirred.

[0015] Furthermore, the heating and ripening process involves heating to 40-60°C and then maintaining that temperature for 2-4 hours.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention uses tetraethyl orthosilicate (TEOS) as a precursor and achieves precise control over the particle size (10~50 nm) of active nano-silica sol by controlling sol-gel reaction parameters (dropping rate, stirring rate, pH value, reaction temperature, and time). The silanol content is 3.5~5.2 mmol / g, with uniform particle size distribution, high surface activity, and rich in silanol groups. This allows it to chemically react with active groups (epoxy groups, amino groups, hydroxyl groups, etc.) in epoxy resin / polyurethane-based reactive polymer emulsions to form a stable cross-linked network structure, significantly improving the interfacial bonding performance of the interface treatment agent. Simultaneously, comparative experiments clarified the negative impact of deviations from the parameter range on particle size distribution, verifying the necessity of parameter control.

[0017] 2. This invention employs a reactive polymer emulsion system formed by compounding epoxy resin emulsion and polyurethane emulsion. This system combines the rigidity and high-temperature resistance of epoxy resin with the flexibility and adhesion of polyurethane. When combined with active nano-silica sol, it achieves highly efficient compatibility between the inorganic phase (nano-silica sol) and the organic phase (polymer emulsion). This solves the technical problem of poor compatibility and easy stratification and agglomeration of inorganic and organic components in existing interface treatment agents. Comparative experiments have verified the performance advantages of the compounded emulsion compared to the single emulsion, improving the comprehensive mechanical properties and stability of the interface treatment agent.

[0018] 3. This invention precisely controls the composite ratio of nano-silica sol and polymer emulsion, optimizes the type and ratio of emulsifier, screens suitable types and amounts of curing agents, and verifies the negative effects of deviations in each ratio and auxiliary parameter range through univariate comparative experiments. It clarifies the optimal ratio range of each component and prepares a composite interface treatment agent with advantages such as high bonding strength, good water resistance, excellent weather resistance, and strong stability. It can be widely used in many fields such as construction, coatings, composite materials, and electronic packaging, and has a wide range of applications.

[0019] 4. The preparation method of the present invention is controllable, simple to operate, and has mild reaction conditions. It does not require high temperature and high pressure, and has low production cost. The performance of the interface treatment agent can be flexibly adjusted by controlling the reaction parameters to meet the needs of different fields and is suitable for large-scale industrial production. At the same time, there is no emission of toxic and harmful gases during the preparation process, and all raw materials used are environmentally friendly materials, which is in line with the development trend of green and environmental protection.

[0020] 5. This invention clarifies the national standard test methods, test substrates, coating amounts, and test conditions for all expected performance indicators, achieving standardization and repeatability of performance testing, and providing a clear and unified basis for product quality inspection, industrial application, and technology promotion. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a process diagram for preparing the interface treatment agent of the present invention; Figure 2 This is a particle size distribution diagram of the active nano-silica sol in Example 1. Detailed Implementation

[0023] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0024] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0025] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0026] The primary objective of this invention is to provide a nano-silica sol composite interface treatment agent with controllable particle size. This interface treatment agent uses active nano-silica sol with a particle size precisely controlled between 10 and 50 nm as its functional component. Its surface silanol content is 3.5 to 5.2 mmol / g. It is composited with epoxy resin / polyurethane-based reactive polymer emulsion to solve the problems of poor compatibility, unstable performance, and insufficient bonding strength of existing interface treatment agents, thereby improving the overall performance of the interface treatment agent.

[0027] Another objective of this invention is to provide a method for preparing the aforementioned composite interface treatment agent. This method is process-controllable and simple to operate. The particle size of the nano-silica sol is controllable by precisely controlling the sol-gel reaction parameters. Comparative experiments were designed to verify the negative impact of parameters such as dropping rate and stirring rate on particle size distribution. By optimizing the composite ratio, emulsifier, and curing agent type, high-efficiency compatibility between silica sol and organic polymer emulsion is achieved. A series of univariate comparative experiments were conducted to verify the regulatory effect of each component, additive, and composite ratio on the performance of the treatment agent, ensuring that the performance of the interface treatment agent is stable and controllable, and suitable for large-scale industrial production.

[0028] The third objective of this invention is to clarify the standard test methods, test substrates, coating processes, and test conditions for all expected performance indicators of the composite interface treatment agent, so as to achieve standardization and repeatability of performance testing and provide a clear basis for product quality inspection and industrial application.

[0029] In some specific embodiments, the particle size controllable nano-silica sol composite interface treatment agent of the present invention is composed of the following components in parts by weight: 15-40 parts of active nano-silica sol, 45-70 parts of epoxy resin / polyurethane-based reactive polymer emulsion, 1-5 parts of emulsifier, 2-8 parts of curing agent, 0.5-3 parts of dispersant, and 5-15 parts of deionized water.

[0030] In some embodiments, the active nano-silica sol is prepared using tetraethyl orthosilicate (TEOS) as a precursor via a sol-gel method. The particle size is controlled at 10-50 nm, and the surface is rich in silanol groups, with a surface silanol content of 3.5-5.2 mmol / g and a particle size variation coefficient ≤15%. The surface contains a large number of silanol groups (-SiOH), exhibiting high reactivity. It can chemically react with the active groups in epoxy resin / polyurethane-based reactive polymer emulsions to form a stable cross-linked network structure.

[0031] In some embodiments, the epoxy resin / polyurethane-based reactive polymer emulsion (hereinafter referred to as polymer emulsion) is a compound system of epoxy resin emulsion and polyurethane emulsion, with a compounding mass ratio of (1~3):1; wherein, the epoxy resin emulsion has an epoxy value of 0.1~0.5 eq / 100g and a solid content of 40~60wt%; the polyurethane emulsion has an NCO group content of 1~5wt% and a solid content of 35~55wt%. The polyurethane emulsion is preferably an aqueous polyurethane emulsion, which has good flexibility and adhesion. When compounded with the epoxy resin emulsion, it can achieve a synergy of rigidity and flexibility, improving the bonding strength and toughness of the interface treatment agent. When using epoxy resin emulsion or polyurethane emulsion alone, the treatment agent cannot simultaneously achieve both rigidity and flexibility, easily resulting in insufficient bonding strength or poor toughness.

[0032] The composite ratio of active nano silica sol and epoxy resin / polyurethane-based reactive polymer emulsion needs to be strictly controlled at 15~40:45~70. When the amount of silica sol added is <15 parts, the bonding strength between the treatment agent and the inorganic substrate is insufficient; when the amount added is >40 parts, the composite system is prone to agglomeration, resulting in decreased toughness and poorer weather resistance.

[0033] In some embodiments, the emulsifier is selected from one or a mixture of two or more of sodium dodecylbenzenesulfonate (SDBS), fatty alcohol polyoxyethylene ether (AEO-9), and nonylphenol polyoxyethylene ether (NP-10). When two emulsifiers are used in combination, the mass ratio of anionic emulsifier (such as SDBS) to nonionic emulsifier (such as AEO-9, NP-10) is (1~2):1, which can significantly improve the compatibility between silica sol and polymer emulsion, prevent the composite system from layering and agglomerating, and ensure the stability of the interface treatment agent. When the single component emulsifier or the ratio of the combination exceeds 1~2:1, the compatibility of the composite system deteriorates, and layering and agglomeration are prone to occur.

[0034] In some embodiments, the curing agent is selected from one or a mixture of two or more aliphatic polyamines, aromatic polyamines, and polyamide curing agents. Preferably, the aliphatic polyamine is ethylenediamine or diethylenetriamine, the aromatic polyamine is preferably m-phenylenediamine, and the polyamide curing agent is preferably polyamide 650 or polyamide 651. The amount of curing agent is precisely controlled according to the content of active groups in the epoxy resin / polyurethane-based reactive polymer emulsion to ensure sufficient cross-linking and curing of the composite system, thereby improving the mechanical properties and weather resistance of the interface treatment agent. When the amount of curing agent is less than 2 parts, the system cross-linking is insufficient, resulting in low bonding strength; when the amount is greater than 8 parts, the system cures too quickly, easily leading to surface cracking and a significant decrease in water resistance.

[0035] In some embodiments, the dispersant is selected from sodium polycarboxylate and polyacrylate dispersants, which can effectively disperse active nano-silica sol, prevent its aggregation, ensure that the nano-silica sol is uniformly distributed in the composite system, and give full play to its interface modification effect. Preferably, the dispersant is sodium polyacrylate, which has excellent dispersion effect and good compatibility with the composite system, and does not affect other properties of the interface treatment agent.

[0036] In some specific implementations, such as Figure 1 The method for preparing the particle size controllable nano-silica sol composite interface treatment agent of the present invention includes the following steps: Step 1: Preparation of active nano-silica sol (sol-gel method) 1.1 Add 20-50 parts of deionized water and 10-30 parts of ethanol to the reaction vessel by weight, stir well, and adjust the pH of the system to 2-4 (using hydrochloric acid or nitric acid) to obtain a mixed solvent system. 1.2 Add 10-25 parts of tetraethyl orthosilicate (TEOS) slowly dropwise to the above mixed solvent system at a rate of 1-3 mL / min. During the dropwise addition, maintain a stirring rate of 300-600 r / min. After the dropwise addition is complete, raise the temperature to 30-50℃ and stir the reaction at a constant temperature for 2-6 h to obtain a silica sol precursor solution. 1.3 Add 0.5-2 parts of ammonia to the silica sol precursor solution, adjust the pH of the system to 7-9, and continue to stir the reaction at a constant temperature for 1-3 h to promote the full progress of the sol-gel reaction and form a nano silica sol system; 1.4 The above-mentioned nano-silica sol system was subjected to vacuum distillation to remove ethanol and excess water from the system. The distillation temperature was controlled at 60~80℃ and the vacuum degree was controlled at 0.05~0.08MPa. The system was distilled until the solid content was 20~40wt% to obtain active nano-silica sol.

[0037] By adjusting the dropping rate, stirring rate, and reaction temperature in step 1.2, and the pH value and reaction time in step 1.3, the particle size of the active nano silica sol can be precisely controlled within the range of 10~50nm, with uniform particle size distribution (particle size variation coefficient ≤15%) and surface silanol content of 3.5~5.2mmol / g. If the parameters deviate from the above range, the particle size distribution will worsen and the activity will be significantly reduced.

[0038] This invention prepares nano-silica sols with different particle size distributions by controlling the sol-gel reaction parameters. When the dropping rate is >3 mL / min, the stirring rate is <300 r / min, the reaction temperature is >50℃ or <30℃, the pH value in step 1.3 is >9 or <7, and the reaction time is >6 h or <1 h, the particle size distribution of the prepared nano-silica sols deteriorates significantly, the particle size variation coefficient is >25%, the silanol content is <3.0 mmol / g, and the compatibility with polymer emulsions decreases significantly.

[0039] Compared with existing technologies, this preparation process effectively solves the technical problems of wide particle size distribution and insufficient activity of nano-silica sol by regulating the sol-gel reaction rate through a two-step acid-base catalysis, while simplifying the process steps and reducing production costs.

[0040] Step 2: Blending of epoxy resin / polyurethane-based reactive polymer emulsion Epoxy resin emulsion and polyurethane emulsion were added to a reaction vessel at a mixing ratio of (1~3):1 by weight, along with 0.5~3 parts of dispersant. The stirring speed was adjusted to 400~800 r / min, and the mixture was stirred at room temperature for 30~60 min to obtain a uniform and stable epoxy resin / polyurethane-based reactive polymer emulsion compound system. This compound system combines the rigidity of epoxy resin and the flexibility of polyurethane. Through the action of the dispersant, the two emulsions are ensured to be fully compatible, laying the foundation for subsequent composite with nano-silica sol. Using epoxy resin or polyurethane emulsion alone cannot achieve the synergy of rigidity and flexibility, resulting in a significant decrease in the overall performance of the treatment agent.

[0041] Step 3: Preparation of composite interface treatment agent 3.1 By weight, slowly add 15-40 parts of the active nano silica sol prepared in step 1 to the polymer emulsion compound system obtained in step 2, keep the stirring rate at 500-800 r / min, stir at room temperature for 1-2 h, so that the nano silica sol is uniformly dispersed in the polymer emulsion. When the amount of silica sol added deviates from the range of 15-40 parts, the treatment agent will have defects such as insufficient bonding strength or agglomeration and stratification. 3.2 Emulsification: Add 1-5 parts of emulsifier to the above mixture, adjust the pH of the system to 6-8 (using ammonia or acetic acid), and continue stirring for 30-60 minutes to ensure that the composite system is uniform and stable, without layering or agglomeration; the type of emulsifier and the compounding ratio must strictly follow the requirements of this invention, otherwise the system compatibility will deteriorate. 3.3 Curing and ripening: Slowly add 2-8 parts of curing agent to the system, adjust the stirring speed to 300-500 r / min, stir at room temperature for 1-2 h, then raise the temperature to 40-60℃ and keep it at a constant temperature for 2-4 h to promote full cross-linking and curing of the system; when the amount of curing agent deviates from the range of 2-8 parts, the cross-linking effect of the system is not good, and problems such as low bonding strength or surface cracking are likely to occur. 3.4 After the curing process is complete, the mixture is allowed to cool naturally to room temperature. It is then filtered (with a filtration precision of 0.22 μm) to remove small amounts of impurities and agglomerates from the system, resulting in a nano-silica sol composite interface treatment agent with controllable particle size.

[0042] In step 3, if the ratio of nano-silica sol to polymer emulsion exceeds 15~40:45~70, the ratio of single component of emulsifier used / compounded exceeds 1~2:1, or the amount of curing agent is <2 parts or >8 parts, the compatibility, bonding strength and storage stability of the treatment agent will decrease significantly.

[0043] This invention achieves efficient compatibility between inorganic nano-silica sol and organic polymer emulsion, resulting in a treatment agent with high bonding strength, excellent water and weather resistance, and stable storage. The preparation process is mild, controllable, green, and environmentally friendly, suitable for large-scale industrial production, and can be widely used in fields such as construction, coatings, composite materials, and electronic packaging.

[0044] Example 1 The nano-silica sol composite interface treatment agent of this embodiment is composed of the following components in parts by weight: 25 parts of active nano-silica sol, 55 parts of epoxy resin / polyurethane-based reactive polymer emulsion (the mass ratio of epoxy resin emulsion to polyurethane emulsion is 2:1, the epoxy value of epoxy resin emulsion is 0.3 eq / 100g, and the solid content is 50%; the NCO group content of polyurethane emulsion is 3%, and the solid content is 45%), 3 parts of emulsifier (sodium dodecylbenzenesulfonate and fatty alcohol polyoxyethylene ether are compounded in a mass ratio of 1.5:1), 5 parts of curing agent (diethylenetriamine and polyamide 650 are compounded in a mass ratio of 1:1), 1.5 parts of dispersant (sodium polyacrylate), and 10 parts of deionized water.

[0045] Its preparation method includes the following steps: Step 1: Preparation of active nano-silica sol 1.1 Add 35 parts of deionized water and 20 parts of ethanol to the reaction vessel, stir well, and adjust the pH of the system to 3 with hydrochloric acid to obtain a mixed solvent system; 1.2 18 parts of tetraethyl orthosilicate were slowly added dropwise to the mixed solvent system at a rate of 2 mL / min. During the dropwise addition, the stirring rate was kept at 450 r / min. After the dropwise addition was completed, the temperature was raised to 40℃ and the reaction was stirred at a constant temperature for 4 h to obtain the silica sol precursor solution. 1.3 Add 1.2 parts of ammonia to the silica sol precursor solution, adjust the pH of the system to 8, and continue to stir the reaction at a constant temperature for 2 hours to form a nano silica sol system; 1.4 The nano-silica sol system was subjected to vacuum distillation at 70℃ and 0.06MPa until the solid content of the system reached 30%, yielding active nano-silica sol. Analysis showed that the active nano-silica sol had a particle size of 20-30 nm, a silanol content of 4.2 mmol / g, and a particle size variation coefficient of 12%. Its particle size distribution curve is shown in the figure. Figure 2 The silanol content was determined by acid-base titration, and the particle size distribution was determined by laser particle size analyzer. When calculating the coefficient of variation of particle size, it is first necessary to calculate the average particle size (μ) and standard deviation (σ) of the particle population. The percentage expression of the coefficient of variation of particle size can be obtained by dividing the standard deviation by the average particle size and multiplying by 100%.

[0046] Step 2: Blending of epoxy resin / polyurethane-based reactive polymer emulsion 37 parts of epoxy resin emulsion and 18 parts of polyurethane emulsion were added to a reaction vessel, along with 1.5 parts of dispersant. The mixture was stirred at 600 r / min at room temperature for 45 min to obtain a polymer emulsion compound system.

[0047] Step 3: Preparation of composite interface treatment agent 3.1 Slowly add 25 parts of the active nano silica sol prepared in step 1 to the polymer emulsion compounding system, keep the stirring rate at 650 r / min, and stir at room temperature for 1.5 h; 3.2 Add 3 parts of emulsifier, adjust the pH of the system to 7 with ammonia, and continue stirring for 45 min to obtain a uniform and stable mixture; 3.3 Slowly add 5 parts of curing agent, adjust the stirring speed to 400 r / min, stir at room temperature for 1.5 h, then heat to 50℃ and cure at a constant temperature for 3 h; 3.4 After naturally cooling to room temperature, the mixture is filtered through a 0.22μm filter membrane to obtain the composite interface treatment agent.

[0048] Example 2 The nano-silica sol composite interface treatment agent of this embodiment is composed of the following components in parts by weight: 15 parts of active nano-silica sol, 70 parts of epoxy resin / polyurethane-based reactive polymer emulsion (the mass ratio of epoxy resin emulsion to polyurethane emulsion is 1:1, the epoxy value of epoxy resin emulsion is 0.1 eq / 100g, and the solid content is 40%; the NCO group content of polyurethane emulsion is 1%, and the solid content is 35%), 1 part of emulsifier (fatty alcohol polyoxyethylene ether), 2 parts of curing agent (ethylenediamine), 0.5 parts of dispersant (sodium polycarboxylate), and 5 parts of deionized water.

[0049] The preparation method is the same as in Example 1, except that the reaction parameters in step 1 are adjusted: dropping rate 1 mL / min, stirring rate 300 r / min, reaction temperature 30℃, reaction time 2 h, pH value adjusted to 2 (step 1.1) and 7 (step 1.3), and distilled to a solid content of 20% to obtain particles with a size of 10~20 mm. The active nano-silica sol has a silanol content of 3.5 mmol / g and a particle size variation coefficient of 10%. In step 2, the compounding ratio is 1:1. In step 3, the amounts of emulsifier and curing agent are adjusted accordingly (main component dosage: active nano-silica sol is adjusted from 25 parts to 15 parts, polymer emulsion compounding system is adjusted from 55 parts to 70 parts; emulsifier: dosage is adjusted from 3 parts to 1 part; type is adjusted from "sodium dodecylbenzenesulfonate + fatty alcohol polyoxyethylene ether (mass ratio 1.5:1)" to single fatty alcohol polyoxyethylene ether; curing agent: dosage is adjusted from 5 parts to 2 parts; type is adjusted from "diethylenetriamine + polyamide 650 (mass ratio 1:1)" to single ethylenediamine; deionized water replenishment is adjusted from 10 parts to 5 parts). The rest is the same as in Example 1.

[0050] Example 3 The nano-silica sol composite interface treatment agent of this embodiment is composed of the following components in parts by weight: 40 parts of active nano-silica sol, 45 parts of epoxy resin / polyurethane-based reactive polymer emulsion (the mass ratio of epoxy resin emulsion to polyurethane emulsion is 3:1, the epoxy value of epoxy resin emulsion is 0.5 eq / 100g, and the solid content is 60%; the NCO group content of polyurethane emulsion is 5%, and the solid content is 55%), 5 parts of emulsifier (nonylphenol polyoxyethylene ether and sodium dodecylbenzene sulfonate are compounded in a mass ratio of 2:1), 8 parts of curing agent (m-phenylenediamine and polyamide 651 are compounded in a mass ratio of 2:1), 3 parts of dispersant (sodium polyacrylate), and 15 parts of deionized water.

[0051] The preparation method is the same as in Example 1, except that the reaction parameters in step 1 are adjusted: dropping rate 3 mL / min, stirring rate 600 r / min, reaction temperature 50℃, reaction time 6 h, pH value adjusted to 4 (step 1.1) and 9 (step 1.3), and distilled to a solid content of 40%, yielding a particle size of 40~50 mm. The active nano-silica sol has a silanol content of 5.2 mmol / g and a particle size variation coefficient of 15%. In step 2, the compounding ratio is 3:1. In step 3, the amounts of emulsifier and curing agent are adjusted accordingly (active nano-silica sol is adjusted from 25 parts to 40 parts, polymer emulsion compounding system is adjusted from 55 parts to 45 parts; emulsifier: the amount is adjusted from 3 parts to 5 parts; the type is adjusted from "sodium dodecylbenzenesulfonate + fatty alcohol polyoxyethylene ether (mass ratio 1.5:1)" to "nonylphenol polyoxyethylene ether + sodium dodecylbenzenesulfonate (mass ratio 2:1)"; curing agent: the amount is adjusted from 5 parts to 8 parts; the type is adjusted from "diethylenetriamine + polyamide 650 (mass ratio 1:1)" to "m-phenylenediamine + polyamide 651 (mass ratio 2:1)"; deionized water replenishment is adjusted from 10 parts to 15 parts). The rest is the same as in Example 1.

[0052] The performance of the composite interface treatment agents prepared in Examples 1-3 and commercially available ordinary interface treatment agents were tested. The performance test methods and test conditions were as follows: (1) Bond strength: tested according to GB / T 33333-2016, the test substrate was C30 concrete, and the coating amount was 80g / m 2 After coating, the glass was cured at room temperature (25±2℃) for 24 hours. The test environment was 25℃ and the relative humidity was 70%. (2) Water resistance: tested according to GB / T 1733-1993. The test substrate was float glass plate and the coating amount was 80g / m 2 After curing at room temperature for 24 hours, soak in distilled water at 25℃ for 24 hours and calculate the water absorption rate; (3) Weather resistance: tested according to GB / T 1865-2009, UV aging for 72 hours, wavelength 340nm, irradiation intensity 0.71W / (m 2 nm), test the retention rate of bonding strength after aging; (4) Storage stability: seal and store at room temperature (25±2℃) for 3 months, and observe whether it separates, agglomerates, or precipitates.

[0053] The test items and results are shown in Table 1: Table 1. Performance comparison of the examples with commercially available common interface treatment agents

[0054] The test results above show that the composite interface treatment agent prepared by the present invention is significantly superior to commercially available ordinary interface treatment agents in terms of bonding strength, water resistance, weather resistance and stability, which fully demonstrates the technical advantages and practical value of the present invention.

[0055] Based on Example 1, multiple groups of nano-silica sols were prepared by changing only the sol-gel reaction parameters. The particle size variation coefficient and silanol content were measured, and the results are shown in Table 2. Table 2. Effects of sol-gel reaction parameters on the expected properties of nano-silica sol.

[0056] Conclusion: When the sol-gel reaction parameters deviate from the limits defined in this invention, the particle size distribution of nano-silica sol deteriorates significantly, the silanol content decreases, and the surface activity drops sharply, making it impossible to achieve high-efficiency compatibility with polymer emulsions.

[0057] Based on Example 1, a control sample was prepared by changing only one variable and tested according to the standard test method specified in this invention (substrate: C30 concrete, coating amount 80g / m²). 2 The performance was tested after curing at room temperature for 24 hours, and the results are shown in Table 3: Table 3 Expected Experimental Results for Performance Comparison

[0058] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A nano-silica sol composite interface treatment agent with controllable particle size, characterized in that, It is composed of the following components in parts by weight: 15-40 parts of active nano silica sol, 45-70 parts of epoxy resin / polyurethane-based reactive polymer emulsion, 1-5 parts of emulsifier, 2-8 parts of curing agent, 0.5-3 parts of dispersant, and 5-15 parts of water. The active nano-silica sol was prepared using tetraethyl orthosilicate as a precursor via a sol-gel method, with a particle size controlled at 10–50 nm, a surface silanol content of 3.5–5.2 mmol / g, and a particle size variation coefficient ≤15%. The epoxy resin / polyurethane-based reactive polymer emulsion is a compound system of epoxy resin emulsion and polyurethane emulsion, with a compound mass ratio of (1~3):

1.

2. The nano-silica sol composite interface treatment agent with controllable particle size according to claim 1, characterized in that, In the epoxy resin / polyurethane-based reactive polymer emulsion, the epoxy value of the epoxy resin emulsion is 0.1~0.5 eq / 100g, and the solid content is 40~60wt%; the NCO group content of the polyurethane emulsion is 1~5wt%, and the solid content is 35~55wt%.

3. The nano-silica sol composite interface treatment agent with controllable particle size according to claim 1, characterized in that, The emulsifier is selected from one or a mixture of two or more of sodium dodecylbenzenesulfonate, fatty alcohol polyoxyethylene ether, and nonylphenol polyoxyethylene ether.

4. The nano-silica sol composite interface treatment agent with controllable particle size according to claim 3, characterized in that, The emulsifier is a mixture of anionic and nonionic emulsifiers in a mass ratio of (1~2):

1.

5. The nano-silica sol composite interface treatment agent with controllable particle size according to claim 1, characterized in that, The curing agent is selected from one or a mixture of two or more of aliphatic polyamines, aromatic polyamines, and polyamide curing agents.

6. The nano-silica sol composite interface treatment agent with controllable particle size according to claim 1, characterized in that, The dispersant is selected from sodium polycarboxylate and polyacrylate dispersants.

7. A method for preparing a nano-silica sol composite interface treatment agent with controllable particle size as described in any one of claims 1 to 6, characterized in that, Includes the following steps: (1) Under stirring, the active nano silica sol is added to the polymer emulsion compounding system and the stirring process continues; the polymer emulsion compounding system is composed of epoxy resin / polyurethane-based reactive polymer emulsion and dispersant; (2) Add emulsifier, adjust the pH of the system to 6-8, and continue stirring; (3) Add curing agent, continue stirring, then heat up to mature, cool and filter to obtain the nano-silica sol composite interface treatment agent with controllable particle size.

8. The method for preparing the nano-silica sol composite interface treatment agent with controllable particle size according to claim 7, characterized in that, The preparation method of the active nano-silica sol is as follows: (1) Tetraethyl orthosilicate is added dropwise to the mixed solvent system at a rate of 1-3 mL / min. During the dropwise addition, the stirring rate is maintained at 300-600 r / min. After the dropwise addition is completed, the temperature is raised to 30-50℃ and the reaction is carried out under constant temperature stirring to obtain a silica sol precursor solution. The mixed solvent system is an ethanol aqueous solution with a pH of 2-4. (2) Adjust the pH of the silica sol precursor solution to 7-9, and continue to stir the reaction at a constant temperature for 1-3 hours to form a nano silica sol system; (3) The nano silica sol system is subjected to vacuum distillation until the solid content of the system is 20~40wt% to obtain active nano silica sol.

9. The method for preparing the nano-silica sol composite interface treatment agent with controllable particle size according to claim 7, characterized in that, The preparation method of the polymer emulsion compound system is as follows: epoxy resin emulsion and polyurethane emulsion are added to a reaction vessel at a compound mass ratio of (1~3):1, then a dispersant is added and the mixture is stirred.

10. The method for preparing the nano-silica sol composite interface treatment agent with controllable particle size according to claim 7, characterized in that, The heating and curing process involves heating to 40-60℃ and maintaining that temperature for 2-4 hours.

Images