Water-based interface agent and preparation method thereof

Abstract

The invention belongs to the technical field of building materials. The invention relates to a water-based interface agent, in particular to a water-based interface agent and a preparation method thereof. The product is prepared from the following raw materials in parts by weight: 80 to 90 parts of waterborne acrylic emulsion, 10 to 15 parts of aluminum oxide coated nano silicon dioxide dispersion liquid, 4 to 6 parts of ethylene glycol, 2 to 4 parts of polyether modified siloxane, 0.8 to 1.2 parts of defoaming agent and 1.2 to 1.5 parts of thickening agent. Wherein the nano silicon dioxide dispersion liquid is obtained by dispersing aluminum oxide coated nano silicon dioxide and water according to a mass ratio of 1: (8-10); the aluminum oxide coated nano silicon dioxide comprises nano silicon dioxide and an aluminum oxide coating layer coated on the surface of the nano silicon dioxide; the D50 of the nano silicon dioxide is 20-25 nm, and the average thickness of the aluminum oxide coating layer is 3-5 nm. The aluminum oxide coated nano silicon dioxide further comprises a transition layer located between the nano silicon dioxide and the aluminum oxide coating layer, and the transition layer comprises amorphous carbon.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials and more specifically relates to a water-based interface agent and a preparation method thereof. Background Art

[0002] Water-based interface agents use water as a solvent, replacing traditional organic solvent-based products, significantly reducing VOC (volatile organic compound) emissions and meeting the requirements of green building and sustainable development.

[0003] The permeability of water-based interface agents is one of their core functions, but in actual applications, there may be problems with insufficient permeability, especially in complex substrates or special environments. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the existing water-based interface agent is prone to insufficient penetration during actual use. In view of the above problem, the present invention provides a water-based interface agent and a preparation method thereof.

[0005] The purpose of the present invention is to provide an aqueous interface agent.

[0006] Another object of the present invention is to provide a method for preparing an aqueous interface agent.

[0007] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0008] A water-based interface agent comprises the following raw materials in parts by weight:

[0009] 80-90 parts of water-based acrylic emulsion, 10-15 parts of alumina-coated nano-silica dispersion, 4-6 parts of ethylene glycol, 2-4 parts of polyether-modified siloxane, 0.8-1.2 parts of defoamer, 1.2-1.5 parts of thickener;

[0010] The nano-silica dispersion is prepared by dispersing alumina-coated nano-silica and water in a mass ratio of 1:8-10.

[0011] The alumina-coated nano-silica comprises nano-silica and an alumina coating layer coated on the surface of the nano-silica;

[0012] The D50 of the nano-silicon dioxide is 20-25 nm, and the average thickness of the aluminum oxide coating layer is 3-5 nm.

[0013] The beneficial effects of the above technical solution are:

[0014] During the research and development process, the inventors discovered that nano-silica particles have a relatively small size, and therefore can penetrate and diffuse into the pores on the surface of the substrate. However, if the size is too small, the presence of silanol groups on the surface of the nano-silica will lead to strong hydrogen bonding forces between the particles, causing agglomeration between the particles, thus affecting their penetration and diffusion into the pores.

[0015] Based on this, the present invention coats a certain thickness of alumina coating layer on the surface of nano-silica. On the one hand, the presence of the alumina coating layer can shield a portion of the silanol groups on the surface of the nano-silica, thereby reducing the hydrogen bonding force between the particles, reducing the occurrence of agglomeration, and improving its dispersion in the interface agent, thereby enhancing the penetration depth; on the other hand, the isoelectric point of alumina is higher than that of silica. After coating, the surface charge of the particles can be adjusted to make them more compatible with the concrete substrate, thereby promoting the wetting and capillary penetration of the water-based interface agent; more importantly, the alumina coating layer can form a smoother surface morphology, reducing the flow resistance of the nanoparticles when penetrating into the pores of the substrate;

[0016] However, the inventors found that if the coating layer is too thick, it will completely block the active sites on the surface of the nano-silica, and if it is too thin, the coating will be uneven. Therefore, the thickness needs to be controlled within a reasonable range; and after the coating treatment, it is further matched with polyether-modified silicone for synergistic use. Specifically, polyether-modified silicone model BYK-349 can be used to offset the possible loss of wetting properties after coating.

[0017] Furthermore, the alumina-coated nano-silica further includes a transition layer between the nano-silica and the alumina coating layer, and the transition layer includes amorphous carbon.

[0018] The beneficial effects of the above technical solution are:

[0019] The inventors further discovered that due to the large difference in thermal expansion coefficients between nano-silica and alumina, during processing and use, the alumina coating may partially fall off due to the inconsistent thermal expansion coefficients between the two, thereby affecting the effect after coating. By setting an amorphous carbon coating between the two, it can serve as a buffer layer to reduce interfacial stress cracking caused by temperature changes.

[0020] Furthermore, a silane coupling agent is grafted onto the surface of the alumina coating layer;

[0021] The silane coupling agent is selected from any one of silane coupling agent KH-540, silane coupling agent KH-550, silane coupling agent KH-560, silane coupling agent KH-570, and silane coupling agent KH-580.

[0022] Furthermore, the aqueous acrylic emulsion includes emulsion particles, the D50 of the emulsion particles is 80-90 nm, and the particle size distribution range of the emulsion particles is 1-200 nm.

[0023] The beneficial effects of the above technical solution are:

[0024] The inventors further discovered that by selecting emulsion particles with a D50 larger than that of nano-silica, the larger emulsion particles can preferentially enter the macro-pores of the substrate during the penetration process. Through capillary action, they open up a penetration path, creating conditions for the subsequent nano-silica to enter smaller pores, thus forming a dual penetration network of "large particles guiding flow + small particles compacting";

[0025] In addition, large-sized emulsion particles will temporarily deform under the shear force of construction, such as the shear force caused by spraying or brushing, which reduces the viscosity of the system and improves the instantaneous fluidity. Nano-silica maintains a high static viscosity to prevent sagging, making the product have both low construction viscosity (for easy penetration) and high static viscosity (to prevent sedimentation).

[0026] Furthermore, the defoamer is selected from any one of the mineral oil defoamer BYK-024, the mineral oil defoamer TegoFoamex810, and the silicone defoamer BYK-028.

[0027] Furthermore, the thickener is selected from any one of carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and carboxymethyl ethyl cellulose.

[0028] A method for preparing a water-based interface agent, the specific preparation steps comprising:

[0029] Preparation of alumina-coated nanosilica dispersion:

[0030] By weight, take 100-110 parts of nano-silicon dioxide, 2000-2200 parts of anhydrous ethanol, 10-12 parts of silane coupling agent KH-550, 20-22 parts of aluminum isopropoxide, 400-450 parts of isopropanol, and 5-6 parts of 25% ammonia water;

[0031] After mixing nano-silicon dioxide and anhydrous ethanol, ultrasonically disperse them to obtain nano-silicon dioxide dispersion;

[0032] Adding silane coupling agent KH-550 to the nano-silica dispersion, heating under reflux at 70-75°C for 2-4 hours to obtain an activated nano-silica dispersion;

[0033] Aluminum isopropoxide and isopropanol are mixed and stirred evenly, and the pH is adjusted to 3.8-4.0. The mixture is heated and stirred at a temperature of 60-62°C and a stirring speed of 200-300 r / min for reaction for 2-3 hours, and then allowed to stand at a temperature of 40°C for 12-14 hours to obtain a transparent aluminum hydroxide sol;

[0034] The activated nano-silica dispersion is slowly added dropwise to the transparent aluminum hydroxide sol at a rate of 4-6 g / min. After the addition is completed, the mixture is stirred at a temperature of 60-65°C and a stirring speed of 300-400 r / min for 4-5 hours. During the reaction, the pH is maintained at 4.2-4.5.

[0035] Heat to 80°C, add ammonia water, stir and react for 20-30 minutes, centrifuge, wash, dry, and then calcine at 400-450°C for 2-3 hours, cool, and discharge to obtain alumina-coated nano-silica;

[0036] The alumina-coated nano-silica and water are dispersed in a mass ratio of 1:8-10 to obtain the product.

[0037] Furthermore, the preparation of the alumina-coated nano-silica dispersion further comprises:

[0038] The nano-silica and glucose are mixed and dispersed in water in a mass ratio of 10:1-1.5, stirred and dispersed uniformly at 60-70°C, concentrated and dried to remove moisture, and then carbonized at 300-320°C in a nitrogen atmosphere for 2-3 hours, and then kept at 190-200°C in an air atmosphere for 10-12 minutes to obtain pretreated nano-silica;

[0039] By treating it in an air atmosphere at a certain temperature, the amorphous carbon is partially oxidized and -COOH functional groups are formed on the surface, thereby improving the bonding strength between the surface aluminum oxide coating layer and the transition layer, and also facilitating the formation of a more uniform coating layer;

[0040] The pretreated nano-silica and anhydrous ethanol are mixed and ultrasonically dispersed to obtain a nano-silica dispersion;

[0041] Add silane coupling agent KH-550 to the nano-silicon dioxide dispersion, heat and reflux at 70-75°C for 2-4 hours to obtain the activated nano-silicon dioxide dispersion.

[0042] Furthermore, the preparation of the alumina-coated nano-silica dispersion further comprises:

[0043] The alumina-coated nano-silica and 80-90% ethanol solution are mixed and dispersed in a mass ratio of 1:10-12 to obtain a dispersion A;

[0044] The silane coupling agent and 80-90% ethanol solution are stirred and evenly mixed in a mass ratio of 1:20-25, and then acetic acid is added dropwise to adjust the pH to 4.5-5.0, followed by stirring and reacting for 30-40 minutes to obtain a hydrolyzed solution;

[0045] The hydrolyzate is added dropwise to the dispersion A. After the addition is complete, the mixture is stirred at 70-75°C for 4-6 hours, and then centrifuged, washed and dried. DETAILED DESCRIPTION

[0046] The present invention is further described below with reference to specific examples, which, however, are not intended to limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0047] Unless otherwise specified, the reagents and materials used in the following examples were commercially available.

[0048] Example 1

[0049] Preparation of alumina-coated nanosilica dispersion:

[0050] Nano-silica and glucose were mixed in a mass ratio of 10:1 and dispersed in water. After being stirred and dispersed uniformly at 60°C, the mixture was concentrated and dried to remove moisture. Subsequently, the mixture was carbonized at 300°C in a nitrogen atmosphere for 2 hours. Subsequently, the mixture was heat-treated at 190°C in an air atmosphere for 10 minutes to obtain pretreated nano-silica.

[0051] The D50 of the nano-silicon dioxide is 20 nm;

[0052] By weight, 100 parts of pretreated nano-silica, 2000 parts of anhydrous ethanol, 10 parts of silane coupling agent KH-550, 20 parts of aluminum isopropoxide, 400 parts of isopropanol, and 5 parts of 25% ammonia water were taken;

[0053] After mixing the pretreated nano-silica and anhydrous ethanol, ultrasonically disperse them at an ultrasonic frequency of 80 kHz for 20 minutes to obtain a nano-silica dispersion;

[0054] Adding silane coupling agent KH-550 to the nano-silica dispersion, heating under reflux at 70°C for 2 hours to obtain an activated nano-silica dispersion;

[0055] Aluminum isopropoxide and isopropanol were mixed and stirred at 100 r / min for 10 minutes, and then the pH was adjusted to 3.8. The mixture was then heated and stirred at 60°C and 200 r / min for 2 hours, and then allowed to stand at 40°C for 12 hours to obtain a transparent aluminum hydroxide sol.

[0056] The activated nano-silica dispersion was slowly added dropwise to the transparent aluminum hydroxide sol at a rate of 4 g / min. After the addition was completed, the mixture was stirred at 60°C and 300 r / min for 4 h. During the reaction, the pH was maintained at 4.2.

[0057] After the reaction is completed, continue heating to 80°C, add ammonia water, stir and react for 20 minutes, centrifuge, wash, dry, and then calcine at 400°C for 2 hours, cool, and discharge to obtain alumina-coated nano-silica;

[0058] By controlling the above process conditions, an aluminum oxide coating layer with an average thickness of 3 nm is formed on the surface of the nano-silicon dioxide;

[0059] Alumina-coated nano-silica and 80% ethanol solution were mixed and dispersed in a mass ratio of 1:10 to obtain dispersion A;

[0060] The silane coupling agent and 80% ethanol solution were stirred and mixed in a mass ratio of 1:20, and acetic acid was added dropwise to adjust the pH to 4.5. The mixture was stirred at 200 r / min at room temperature for 30 minutes to obtain a hydrolyzed solution.

[0061] The hydrolyzed liquid was added dropwise to the dispersion A. After the addition was completed, the mixture was stirred at 70°C and a stirring rate of 300 r / min for 4 hours, and then centrifuged, washed and dried to further coat the surface of the alumina-coated nano-silica with a silane coupling agent.

[0062] The silane coupling agent is selected from silane coupling agent KH-550;

[0063] Dispersing the alumina-coated nano-silica coated with a silane coupling agent and water in a mass ratio of 1:8 to obtain an alumina-coated nano-silica dispersion;

[0064] According to the weight ratio, take 80 parts of water-based acrylic emulsion, 10 parts of alumina-coated nano-silica dispersion, 4 parts of ethylene glycol, 2 parts of polyether-modified siloxane, 0.8 parts of defoamer, and 1.2 parts of thickener;

[0065] The solid content of the aqueous acrylic emulsion is 40%, and the aqueous acrylic emulsion includes emulsion particles, the D50 of the emulsion particles is 80 nm, and the particle size distribution range of the emulsion particles is 1-200 nm;

[0066] The defoamer is selected from mineral oil defoamer BYK-024; the thickener is selected from carboxymethyl cellulose;

[0067] First, mix the water-based acrylic emulsion and the alumina-coated nano-silica dispersion, and then stir them with a stirrer at a rate of 300r / min for 20 minutes. Then, add ethylene glycol, polyether-modified silicone, defoamer and thickener in sequence while stirring. Continue stirring for 2 hours, let it stand, and discharge the material to obtain the water-based interface agent product.

[0068] Example 2

[0069] Preparation of alumina-coated nanosilica dispersion:

[0070] Nano-silica and glucose were mixed in a mass ratio of 10:1.2 and dispersed in water. After being stirred and dispersed uniformly at 65°C, the mixture was concentrated and dried to remove moisture. Subsequently, the mixture was carbonized at 310°C in a nitrogen atmosphere for 2.4 hours. Subsequently, the mixture was heat-treated at 195°C in an air atmosphere for 11 minutes to obtain pretreated nano-silica.

[0071] The D50 of the nano-silicon dioxide is 22 nm;

[0072] By weight, 105 parts of pretreated nano-silica, 2100 parts of anhydrous ethanol, 11 parts of silane coupling agent KH-550, 21 parts of aluminum isopropoxide, 420 parts of isopropanol, and 5.2 parts of 25% ammonia water were taken;

[0073] After mixing the pretreated nano-silica and anhydrous ethanol, ultrasonically disperse them at an ultrasonic frequency of 90 kHz for 25 minutes to obtain a nano-silica dispersion;

[0074] Adding silane coupling agent KH-550 to the nano-silica dispersion, heating under reflux at 72°C for 3 hours to obtain an activated nano-silica dispersion;

[0075] Aluminum isopropoxide and isopropanol were mixed and stirred at 100 r / min for 10 minutes, and then the pH was adjusted to 3.9. The mixture was then heated and stirred at 61°C and 260 r / min for 2.6 hours, and then allowed to stand at 40°C for 13 hours to obtain a transparent aluminum hydroxide sol.

[0076] The activated nano-silica dispersion was slowly added dropwise to the transparent aluminum hydroxide sol at a rate of 5 g / min. After the addition was complete, the mixture was stirred at 62°C and 350 r / min for 4.5 h. During the reaction, the pH was maintained at 4.3.

[0077] After the reaction is completed, continue heating to 80°C, add ammonia water, stir and react for 26 minutes, centrifuge, wash, dry, and then calcine at 420°C for 2.5 hours, cool, and discharge to obtain alumina-coated nano-silica;

[0078] By controlling the above process conditions, an aluminum oxide coating layer with an average thickness of 4 nm is formed on the surface of the nano-silicon dioxide;

[0079] Alumina-coated nano-silica and 85% ethanol solution were mixed and dispersed in a mass ratio of 1:11 to obtain dispersion A;

[0080] The silane coupling agent and 85% ethanol solution were stirred and mixed in a mass ratio of 1:22, and acetic acid was added dropwise to adjust the pH to 4.8. The mixture was stirred at 200 r / min at room temperature for 35 minutes to obtain a hydrolyzed solution.

[0081] The hydrolyzed liquid was added dropwise to the dispersion A. After the addition was completed, the mixture was stirred at 72°C and a stirring rate of 300 r / min for 5 hours. The mixture was then centrifuged, washed and dried to further coat the surface of the alumina-coated nano-silica with a silane coupling agent.

[0082] The silane coupling agent is selected from silane coupling agent KH-560;

[0083] Dispersing the alumina-coated nano-silica coated with a silane coupling agent and water in a mass ratio of 1:9 to obtain an alumina-coated nano-silica dispersion;

[0084] According to the weight ratio, take 85 parts of aqueous acrylic emulsion, 12 parts of alumina-coated nano-silica dispersion, 5 parts of ethylene glycol, 3 parts of polyether-modified siloxane, 1.0 part of defoamer, and 1.3 parts of thickener;

[0085] The solid content of the aqueous acrylic emulsion is 41%, and the aqueous acrylic emulsion includes emulsion particles, the D50 of the emulsion particles is 85 nm, and the particle size distribution range of the emulsion particles is 1-200 nm;

[0086] The defoaming agent is selected from the mineral oil defoaming agent Tego Foamex810; the thickening agent is selected from hydroxyethyl cellulose;

[0087] First, mix the water-based acrylic emulsion and the alumina-coated nano-silica dispersion, and then stir them with a stirrer at a rate of 400r / min for 25 minutes. Then, add ethylene glycol, polyether-modified silicone, defoamer and thickener in sequence while stirring. Continue stirring and mixing for 2.5 hours, let it stand, and discharge the material to obtain the water-based interface agent product.

[0088] Example 3

[0089] Preparation of alumina-coated nanosilica dispersion:

[0090] Nano-silica and glucose were mixed in a mass ratio of 10:1.5 and dispersed in water. After being stirred and dispersed uniformly at 70°C, the mixture was concentrated and dried to remove moisture. Subsequently, the mixture was carbonized at 320°C in a nitrogen atmosphere for 3 hours, and then kept at 200°C in an air atmosphere for 12 minutes to obtain pretreated nano-silica.

[0091] The D50 of the nano-silicon dioxide is 25 nm;

[0092] By weight, 110 parts of pretreated nano-silica, 2200 parts of anhydrous ethanol, 12 parts of silane coupling agent KH-550, 22 parts of aluminum isopropoxide, 450 parts of isopropanol, and 6 parts of 25% ammonia water were taken;

[0093] After mixing the pretreated nano-silica and anhydrous ethanol, ultrasonically disperse them at an ultrasonic frequency of 100 kHz for 30 minutes to obtain a nano-silica dispersion;

[0094] Adding silane coupling agent KH-550 to the nano-silica dispersion, heating under reflux at 75°C for 4 hours to obtain an activated nano-silica dispersion;

[0095] Aluminum isopropoxide and isopropanol were mixed and stirred at 100 r / min for 10 minutes, and then the pH was adjusted to 4.0. The mixture was then heated and stirred at 62°C and 300 r / min for 3 hours, and then allowed to stand at 40°C for 14 hours to obtain a transparent aluminum hydroxide sol.

[0096] The activated nano-silica dispersion was slowly added dropwise to the transparent aluminum hydroxide sol at a rate of 6 g / min. After the addition was completed, the mixture was stirred at 65°C and 400 r / min for 5 h. During the reaction, the pH was maintained at 4.5.

[0097] After the reaction is completed, continue heating to 80°C, add ammonia water, stir and react for 30 minutes, centrifuge, wash, dry, and then calcine at 450°C for 3 hours, cool, and discharge to obtain alumina-coated nano-silica;

[0098] By controlling the above process conditions, an aluminum oxide coating layer with an average thickness of 5 nm is formed on the surface of the nano-silicon dioxide;

[0099] Alumina-coated nano-silica and 90% ethanol solution were mixed and dispersed in a mass ratio of 1:12 to obtain dispersion A;

[0100] The silane coupling agent and 90% ethanol solution were stirred and mixed in a mass ratio of 1:25, and acetic acid was added dropwise to adjust the pH to 5.0. The mixture was stirred at 200 r / min at room temperature for 40 minutes to obtain a hydrolyzed solution.

[0101] The hydrolyzed liquid was added dropwise to the dispersion A. After the addition was complete, the mixture was stirred at 75°C and a stirring rate of 300 r / min for 6 hours. The mixture was then centrifuged, washed, and dried to further coat the surface of the alumina-coated nano-silica with a silane coupling agent.

[0102] The silane coupling agent is selected from silane coupling agent KH-570;

[0103] Dispersing the alumina-coated nano-silica coated with a silane coupling agent and water in a mass ratio of 1:10 to obtain an alumina-coated nano-silica dispersion;

[0104] According to the weight ratio, take 90 parts of aqueous acrylic emulsion, 15 parts of alumina-coated nano-silica dispersion, 6 parts of ethylene glycol, 4 parts of polyether-modified siloxane, 1.2 parts of defoamer, and 1.5 parts of thickener;

[0105] The solid content of the aqueous acrylic emulsion is 42%, and the aqueous acrylic emulsion includes emulsion particles, the D50 of the emulsion particles is 90 nm, and the particle size distribution range of the emulsion particles is 1-200 nm;

[0106] The defoaming agent is selected from mineral oil defoaming agent BYK-024; the thickening agent is selected from hydroxypropyl cellulose;

[0107] First, mix the water-based acrylic emulsion and the alumina-coated nano-silica dispersion, and then stir them with a stirrer at a speed of 500r / min for 30 minutes. Then, add ethylene glycol, polyether-modified silicone, defoamer and thickener in sequence while stirring. Continue stirring for 3 hours, let it stand, and discharge the material to obtain the water-based interface agent product.

[0108] Example 4

[0109] Compared with Example 1, this embodiment differs in that: no amorphous carbon transition layer is formed between the nano-silica and the alumina coating layer. Specifically, the nano-silica is not pretreated to be coated with amorphous carbon and is directly used; other conditions remain unchanged.

[0110] Example 5

[0111] Compared with Example 1, this embodiment differs in that:

[0112] Nano-silica and glucose were mixed in a mass ratio of 10:1 and dispersed in water. After being stirred and dispersed uniformly at 60°C, the mixture was concentrated and dried to remove moisture. Subsequently, the mixture was carbonized at 300°C in a nitrogen atmosphere for 2 hours and cooled to room temperature to obtain pretreated nano-silica.

[0113] The rest of the conditions remain unchanged.

[0114] Example 6

[0115] Compared with Example 1, this embodiment has the following differences:

[0116] The aqueous acrylic emulsion includes emulsion particles, the D50 of the emulsion particles is 20 nm, and the particle size distribution range of the emulsion particles is 1-130 nm; other conditions remain unchanged.

[0117] Comparative Example 1

[0118] Compared with Example 1, this comparative example has the following differences:

[0119] The surface of nano-silica was used directly without any coating, i.e., it was not pre-treated to coat amorphous carbon or aluminum oxide;

[0120] The rest of the conditions remain unchanged.

[0121] The performance of the products obtained in the above examples and comparative examples was tested, and the specific test methods and test results are as follows:

[0122] Dye-profile method for assessing penetration depth:

[0123] A C30 concrete test block with a porosity of 18% was used as a substrate. The product obtained in the above examples or comparative examples was sprayed onto the substrate surface using a spraying process. The sprayed wet film thickness was controlled to be 20 μm. The substrate was then dried and cured at room temperature for 24 hours. Rhodamine B fluorescent dye was then sprayed. The sprayed wet film thickness was controlled to be 8 μm. After standing for 10 minutes, the surface was rinsed with clean water. The substrate was then cut and the staining depth of the cross section was observed using a digital microscope. The detailed test results are shown in Table 1.

[0124] Water absorption test:

[0125] A C30 concrete specimen with a porosity of 18% was used as the substrate. The water absorption of the substrate was tested before spraying the water-based interface agent. The coating was then sprayed onto the substrate surface using a spraying process. The sprayed wet film thickness was controlled to be 20 μm. The specimen was then dried and cured at room temperature for 24 hours. The water absorption of the substrate after spraying was tested again, and the difference in water absorption was calculated. The results are shown in Table 1.

[0126] When testing the water absorption rate, first immerse the substrate completely in deionized water at room temperature for 30 minutes, then take it out and drain the water. The water absorption rate is calculated by dividing the difference in mass before and after immersion by the mass of the substrate itself.

[0127] Table 1: Product performance test results

[0128] Penetration depth / mm Water absorption difference / % Example 1 9.8 7.2 Example 2 9.9 7.3 Example 3 10.1 7.4 Example 4 9.4 6.8 Example 5 9.5 7.0 Example 6 9.2 6.5 Comparative Example 1 7.1 5.0

[0129] It can be seen from the test results in Table 1 that the product obtained by the present invention has a good penetration effect, can penetrate to a deeper depth, and has a more excellent interface treatment effect on the substrate surface.

[0130] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A water-based interface agent, characterized in that The composition comprises the following raw materials in parts by weight: 80-90 parts of water-based acrylic emulsion, 10-15 parts of alumina-coated nano-silica dispersion, 4-6 parts of ethylene glycol, 2-4 parts of polyether-modified siloxane, 0.8-1.2 parts of defoamer, 1.2-1.5 parts of thickener; The nano-silica dispersion is prepared by dispersing alumina-coated nano-silica and water in a mass ratio of 1:8-10. The alumina-coated nano-silica comprises nano-silica and an alumina coating layer coated on the surface of the nano-silica; The D50 of the nano-silicon dioxide is 20-25 nm, and the average thickness of the aluminum oxide coating layer is 3-5 nm.

2. A water-based interface agent according to claim 1, characterized in that: The alumina-coated nano-silica further comprises a transition layer between the nano-silica and the alumina coating layer, wherein the transition layer comprises amorphous carbon.

3. A water-based interface agent according to claim 2, characterized in that: A silane coupling agent is grafted onto the surface of the alumina coating layer; The silane coupling agent is selected from any one of silane coupling agent KH-540, silane coupling agent KH-550, silane coupling agent KH-560, silane coupling agent KH-570, and silane coupling agent KH-580.

4. The aqueous interface agent according to claim 1, characterized in that: The aqueous acrylic emulsion includes emulsion particles, the D50 of the emulsion particles is 80-90 nm, and the particle size distribution range of the emulsion particles is 1-200 nm.

5. The aqueous interface agent according to claim 1, characterized in that: The defoamer is selected from any one of mineral oil defoamer BYK-024, mineral oil defoamer Tego Foamex810, and silicone defoamer BYK-028.

6. The aqueous interface agent according to claim 1, characterized in that: The thickener is selected from any one of carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose and carboxymethyl ethyl cellulose.

7. A method for preparing the aqueous interface agent according to any one of claims 1 to 6, characterized in that: The specific preparation steps include: Preparation of alumina-coated nanosilica dispersion: By weight, take 100-110 parts of nano-silicon dioxide, 2000-2200 parts of anhydrous ethanol, 10-12 parts of silane coupling agent KH-550, 20-22 parts of aluminum isopropoxide, 400-450 parts of isopropanol, and 5-6 parts of 25% ammonia water; After mixing nano-silicon dioxide and anhydrous ethanol, ultrasonically disperse them to obtain nano-silicon dioxide dispersion; Adding silane coupling agent KH-550 to the nano-silica dispersion, heating under reflux at 70-75°C for 2-4 hours to obtain an activated nano-silica dispersion; Aluminum isopropoxide and isopropanol are mixed and stirred evenly, and the pH is adjusted to 3.8-4.

0. The mixture is heated and stirred at a temperature of 60-62°C and a stirring speed of 200-300 r / min for reaction for 2-3 hours, and then allowed to stand at a temperature of 40°C for 12-14 hours to obtain a transparent aluminum hydroxide sol; Slowly add the activated nano-silica dispersion to the transparent aluminum hydroxide sol, and after the addition is completed, stir the mixture at a temperature of 60-65°C and a stirring speed of 300-400 r / min for 4-5 hours. During the reaction, maintain the pH at 4.2-4.5; Heat to 80°C, add ammonia water, stir and react for 20-30 minutes, centrifuge, wash, dry, and then calcine at 400-450°C for 2-3 hours, cool, and discharge to obtain alumina-coated nano-silica; The alumina-coated nano-silica and water are dispersed in a mass ratio of 1:8-10 to obtain the product.

8. The method for preparing a water-based interface agent according to claim 7, characterized in that: The preparation of the alumina-coated nano-silica dispersion also includes: The nano-silica and glucose are mixed and dispersed in water in a mass ratio of 10:1-1.5, stirred and dispersed uniformly at 60-70°C, concentrated and dried to remove moisture, and then carbonized at 300-320°C in a nitrogen atmosphere for 2-3 hours, and then kept at 190-200°C in an air atmosphere for 10-12 minutes to obtain pretreated nano-silica; The pretreated nano-silica and anhydrous ethanol are mixed and ultrasonically dispersed to obtain a nano-silica dispersion; Add silane coupling agent KH-550 to the nano-silicon dioxide dispersion, heat and reflux at 70-75°C for 2-4 hours to obtain the activated nano-silicon dioxide dispersion.

9. The method for preparing a water-based interface agent according to claim 8, characterized in that: The preparation of the alumina-coated nano-silica dispersion also includes: The alumina-coated nano-silica and 80-90% ethanol solution are mixed and dispersed in a mass ratio of 1:10-12 to obtain a dispersion A; The silane coupling agent and 80-90% ethanol solution are stirred and evenly mixed in a mass ratio of 1:20-25, and then acetic acid is added dropwise to adjust the pH to 4.5-5.0, followed by stirring and reacting for 30-40 minutes to obtain a hydrolyzed solution; The hydrolyzate is added dropwise to the dispersion A. After the addition is complete, the mixture is stirred and reacted at 70-75°C for 4-6 hours, and then centrifuged, washed and dried.