High-fluorine-content silane emulsion as well as preparation method and application thereof

Abstract

The invention relates to the technical field of civil engineering material protection, in particular to a high-fluorine-content silane emulsion as well as a preparation method and application thereof. The high-fluorine-content silane emulsion comprises the following raw materials in parts by weight: 2.5-3.0 parts of an emulsifier, 0.5-1 part of polyethylene glycol, 2-3 parts of a silicone acrylic emulsion, 12-16 parts of water and 74-81 parts of silane, 2-3 parts of nano zinc oxide; wherein the emulsifying agent is prepared from peregal O and Span80; the silane is prepared from 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane and isooctyl triethoxysilane, and the silane is prepared from the following components: 1, 1, 2, 3-perfluorooctyltriethoxysilane and isooctyl triethoxysilane. The high-fluorine-content silane emulsion provided by the invention not only has strong self-stability, but also has good adhesive force, strong permeability and excellent hydrophobic performance after being sprayed or brushed on the surface of concrete, and also has a photocatalytic self-cleaning effect.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering material protection, and in particular to a high-fluorine-containing silane emulsion, a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Concrete is one of the most widely used building materials today, with applications in road and railway construction, canal dams, marine engineering, the machinery industry, power plants, and airport construction. However, due to concrete's hydrophilic nature, water droplets are drawn into the concrete by capillary action through the micropores on its surface, severely impacting its performance. Concrete surfaces are dotted with nanometer- to millimeter-scale micropores. In coastal projects, saline soils, and cold climates, concrete's service life is often reduced by surface cracking and shedding, acid rain erosion, freeze-thaw cycles, and internal steel corrosion. Therefore, improving the waterproofing properties of concrete surfaces is crucial for enhancing the durability of cementitious materials.

[0004] Applying a coating on the surface of a concrete substrate is a simple and effective method to improve the durability of existing or newly built concrete structures. Among them, hydrophobic impregnation coatings can be applied to the surface of concrete to modify the concrete surface to be hydrophobic, and are commonly used concrete surface waterproofing treatment materials. This type of coating penetrates into the interior of the concrete and forms a hydrophobic layer on the surface of the concrete to improve the waterproof and anti-seepage capabilities of the concrete. It has the advantages of convenient construction, high efficiency and durable protection. Silane liquid materials are representatives of high-performance hydrophobic impregnation coatings. However, silane liquid materials have strong fluidity and volatility. Some products need to be diluted with organic solvents, which poses certain environmental problems. During construction, they are easily affected by the coating position, temperature and wind speed. Less than 30% of silane is actually applied to the concrete matrix. In addition, the material needs to be stored dry and sealed to avoid hydrolysis and cross-linking of the material itself, gelation failure, and high storage and transportation conditions.

[0005] To address these issues, converting silane liquid into silane emulsions through emulsification technology is an effective solution. However, current silane emulsions generally suffer from weak hydrophobic protection due to their low silane content (generally below 60%). Increasing the silane content can lead to poor stability and stratification. Furthermore, silane emulsions generally exhibit high fluidity, resulting in weak adhesion and shallow penetration when applied to concrete surfaces. Therefore, a silane emulsion material with a high silane content, excellent stability, strong adhesion, and superior hydrophobicity and permeability is urgently needed. Summary of the Invention

[0006] In order to overcome the above problems, the present invention provides a high-fluorine-containing silane emulsion and a preparation method and application thereof.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: The first aspect of the present invention provides a high-fluorine-containing silane emulsion, the raw materials of which include, by weight: 2.5-3.0 parts of emulsifier, 0.5-1 part of polyethylene glycol, 2-3 parts of silicone acrylic emulsion, 12-16 parts of water, 74-81 parts of silane; 2-3 parts of nano zinc oxide; Wherein, the emulsifier consists of peregal O and Span80; The silane consists of 1H,1H,2H,2H-perfluorooctyltriethoxysilane and isooctyltriethoxysilane.

[0008] In one or more embodiments, the mass ratio of peregal O to Span 80 is (1.5-2):1.

[0009] In one or more embodiments, the mass ratio of 1H,1H,2H,2H-perfluorooctyltriethoxysilane to isooctyltriethoxysilane is 1:1.

[0010] In one or more embodiments, the polyethylene glycol is PEG2000.

[0011] In one or more embodiments, the silicone acrylic emulsion is silicone acrylic emulsion BF-400B.

[0012] The second aspect of the present invention provides a method for preparing the high fluorine-containing silane emulsion according to the first aspect, comprising the following steps: (1) Mixing silane and nano zinc oxide uniformly to obtain modified nano zinc oxide silane suspension A; (2) Mix the nano zinc oxide silane suspension A and Span80 to obtain oil phase B; (3) Mixing chlorpyrifos O, polyethylene glycol, and water to obtain aqueous phase C; (4) Add the oil phase B to the water phase C and emulsify to obtain emulsion D; (5) Add the silicone acrylic emulsion to emulsion D and mix well to obtain a high fluorine-containing silane emulsion.

[0013] In one or more embodiments, in step (1), the mixing conditions are: stirring at 35-40°C and 2000-2400 r / min for 2-2.5 hours. The modified nano-zinc oxide silane suspension A prepared under these conditions can effectively disperse and modify the nano-zinc oxide, improve compatibility, and avoid affecting the preparation of emulsion D.

[0014] In one or more embodiments, in step (2), the mixing conditions are: stirring at 35-40°C and 700-800 r / min for 1-2 minutes. Preparing oil phase B under these conditions not only allows for faster mixing of the materials but also avoids affecting the preparation of emulsion D.

[0015] In one or more embodiments, in step (3), the mixing conditions are: stirring at 35-40°C and 700-800 r / min for 1-2 minutes. Preparing aqueous phase C under these conditions not only allows for faster mixing of the materials but also avoids affecting the preparation of emulsion D.

[0016] In one or more embodiments, in step (4), when the oil phase B is added to the water phase C, the oil phase B and the water phase C are continuously stirred at 35-40°C and 700-800 r / min, and the addition time is 5-10 minutes. Under these conditions, an emulsion D with better stability can be obtained.

[0017] In one or more embodiments, in step (5), the emulsification conditions are: emulsification at 35-40°C and stirring at 2000-2400 r / min for 1.5-2 h. Under these conditions, an emulsion D with better stability can be obtained.

[0018] In one or more embodiments, in step (5), the mixing conditions are: stirring at 35-40°C and 700-800 r / min for 5-10 minutes. Under these conditions, emulsion D and the silicone acrylic emulsion can be evenly mixed, and the imbalance of the two emulsion states that may be caused by rapid addition is avoided, thereby ensuring the success rate of preparing the high-fluorine-containing silane emulsion.

[0019] The third aspect of the present invention provides the use of the high-fluorine-containing silane emulsion described in the first aspect or the high-fluorine-containing silane emulsion prepared by the preparation method described in the second aspect in concrete structure surface protection projects.

[0020] In one or more embodiments, the application includes applying the high fluorine-containing silane emulsion to the concrete surface, applying the emulsion once, and applying the emulsion in an amount of 280-320 g / m 2 .

[0021] When applying a high-fluorine silane emulsion to a concrete surface, the zero period should be ≥28 days for newly constructed concrete structures before application. After applying the high-fluorine silane emulsion to a concrete surface, the concrete surface should be kept dry for at least 7 days. New concrete must have a zero period of at least 28 days before application to prevent the silane from affecting structural strength. The prepared high-fluorine silane emulsion has a certain viscosity after application to the concrete surface, resulting in minimal sagging and loss, allowing for a single application. The set application amount ensures a sufficient total application volume to meet hydrophobicity and penetration depth requirements. A certain drying time ensures that the emulsion fully reacts with the concrete matrix, better maximizing the protective effect of the high-fluorine silane emulsion on the concrete surface.

[0022] The beneficial effects of the present invention are: (1) The high-fluorine-containing silane emulsion provided by the present invention is not only highly stable in itself, but also has good adhesion after being sprayed or brushed onto the concrete surface, strong permeability, excellent hydrophobicity, and a photocatalytic self-cleaning effect. In the present invention, by reasonably setting the order of addition of raw materials, as well as the preparation temperature, stirring rate and time, the silane as a discontinuous phase can be more stably dispersed in the water as a continuous phase, thereby ensuring that the obtained octyl fluorine-containing modified nano zinc oxide silane emulsion is more stable and uniform; in the present invention, by increasing the silane content and compounding the silicone acrylic emulsion system with nano zinc oxide, the hydrophobicity is jointly improved. Nano zinc oxide can be fixed on the concrete surface with the help of the film-forming property of the silicone acrylic emulsion, thereby increasing the roughness to improve the hydrophobicity; at the same time, the photocatalytic effect of nano zinc oxide can generate active oxygen, so that the hydrophobic surface has a certain self-cleaning ability, protecting the hydrophobic coating from the influence of organic pollutants and keeping the substrate surface clean and tidy. By adjusting the silane content and ratio, the viscosity of the emulsion is enhanced, effectively improving the adhesion and permeability of the emulsion on the concrete surface after coating; 1H,1H,2H,2H-perfluorooctyltriethoxysilane and isooctyltriethoxysilane are used as core hydrophobic components. At the optimal mixing ratio, the emulsion itself has a certain viscosity. After coating on the concrete surface, water as the continuous phase will be pre-adsorbed by the concrete. After the emulsion loses water, the viscosity increases significantly and the adhesion is improved. On this basis, the emulsion breaks and releases hydrophobic silane, effectively increasing the penetration depth.

[0023] (2) An emulsion is essentially a mixed system formed by immiscible liquids (such as water and oil) through a specific stabilizer. This mixture is always in a dynamic equilibrium state. Compared with completely miscible solutions, substances in an emulsion are more likely to separate by stratification. The high-fluorine-containing silane emulsion in the present invention is mainly used for surface waterproofing of concrete materials. Therefore, it faces the following challenges during the preparation process: On the one hand, if the hydrophobic effect is increased, the content of silane with a hydrophobic effect needs to be increased in the emulsion. However, increasing the content of silane will break the original hydrophilic-lipophilic balance, resulting in the inability of tiny droplets to be stably suspended, but accelerating stratification; on the other hand, if additional hydrophobic components are introduced, the surface charge or physical spatial distribution of the emulsion particles may be changed, thereby affecting the overall stability. Therefore, how to effectively improve the waterproof performance and adhesion without destroying the stability of the emulsion has become the core difficulty in preparing the high-fluorine-containing silane emulsion. To this end, the emulsification system of the present invention selects non-ionic surfactants with stronger adaptability, namely Span 80 and Parga O as composite emulsifiers, and polyethylene glycol as dispersant, which can ensure the formation of emulsion within a preferred ratio range; on this basis, the nano-zinc oxide compounded silicone-acrylic emulsion system used in the emulsion further ensures the stability of the emulsion; in order to make the prepared emulsion stable and uniform, the present invention pre-mixes the nano-zinc oxide and silane to hydrophobically modify the nano-zinc oxide, effectively improving its dispersibility in the emulsion, and the finished emulsion is more stable; in order to avoid damage to the existing emulsion system caused by premature addition of the silicone-acrylic emulsion, the two emulsions are mixed after the emulsion D is emulsified and stabilized; by reasonably setting the order of adding raw materials as well as the preparation temperature, stirring rate and time, the silane as the discontinuous phase can be more stably dispersed in the water as the continuous phase, thereby ensuring that the obtained high-fluorine-containing silane emulsion is more stable and uniform.

[0024] (3) The high-fluorine-containing silane emulsion prepared by the present invention has a certain viscosity, and has little loss after coating. It can be coated in one go, and the coating amount is small. However, the thickness of the hydrophobic layer formed is about 1.5 times that of the ordinary emulsion, and the water absorption rate is further reduced by nearly 10%. The surface contact angle can reach more than 130°, and it also has a photocatalytic self-cleaning effect, which can oxidize and decompose surface organic pollutants, protect the hydrophobicity of the coating, and keep the coating surface clean and tidy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] Figure 11 is a comparison diagram of the high-fluorine-containing silane emulsion prepared in Example 1 and the emulsion in Comparative Example 1 applied to mortar specimens; wherein, a is the coating result of the high-fluorine-containing silane emulsion prepared in Example 1, and is held at an angle, and b is the coating result of the emulsion in Comparative Example 1, and is placed horizontally; Figure 2 is the contact angle of the emulsions prepared in Examples 1 to 3 and Comparative Examples 1 to 2 and 4; Figure 3 is the penetration depth of the emulsions prepared in Examples 1 to 3 and Comparative Examples 1 to 2 and 4; Figure 4 It is the test result of photocatalysis test. DETAILED DESCRIPTION

[0027] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0030] The water used in the following examples is deionized water, which can avoid the introduction of impurity ions from the water and prevent the reduction of emulsion stability.

[0031] In the following examples, the polyethylene glycol is PEG2000; and the silicone acrylic emulsion is silicone acrylic emulsion BF-400B.

[0032] Example 1 A high-fluorine-containing silane emulsion, the raw materials of which include, by weight: 2.5 parts of emulsifier, 0.5 parts of polyethylene glycol, 2 parts of silicone acrylic emulsion, 12 parts of water, 81 parts of silane, 2 parts of nano zinc oxide; In the emulsifier, Span80 0.83 parts, Peregal O 1.67 parts; Among the silanes, 40.5 parts of 1H,1H,2H,2H-perfluorooctyltriethoxysilane and 40.5 parts of isooctyltriethoxysilane were used.

[0033] The preparation method of high fluorine-containing silane emulsion comprises: (1) 1H,1H,2H,2H-perfluorooctyltriethoxysilane, isooctyltriethoxysilane and nano zinc oxide were added to a container, heated and maintained at 40 °C, and stirred at 2000 r / min for 2 h to obtain modified nano zinc oxide silane suspension A; (2) Nano-zinc oxide silane suspension A and Span80 were stirred at 40 °C and 800 r / min for 1 min to obtain oil phase B; (3) Take another clean container, add PEG-2000, deionized water, and PEG-2000, heat and maintain the temperature at 40 °C, and stir at 800 rpm for 2 min to obtain a uniform aqueous phase C. (4) Keeping the temperature and stirring speed constant, continue stirring the oil phase B and the water phase C, and add the oil phase B to the water phase C at the same time. The addition time is 10 min, and then emulsify at a stirring speed of 2000 r / min for 2 h to obtain emulsion D; (5) Add the silicone acrylic emulsion to emulsion D for 2 min and stir at 40 °C and 800 r / min for 8 min to obtain a high fluorine-containing silane emulsion.

[0034] Example 2 A high-fluorine-containing silane emulsion, the raw materials of which include, by weight: 3.0 parts of emulsifier, 1 part of polyethylene glycol, 3 parts of silicone acrylic emulsion, 16 parts of water, 74 parts of silane, 3 parts of nano zinc oxide; In the emulsifier, Span80 1.1 parts, Peregal O 1.9 parts; Among the silanes, 37 parts of 1H,1H,2H,2H-perfluorooctyltriethoxysilane and 37 parts of isooctyltriethoxysilane were used.

[0035] The preparation method of high fluorine-containing silane emulsion comprises: (1) 1H,1H,2H,2H-perfluorooctyltriethoxysilane, isooctyltriethoxysilane and nano zinc oxide were added to a container, heated and maintained at 36 °C, and stirred at 2200 r / min for 2 h to obtain modified nano zinc oxide silane suspension A; (2) Nano-zinc oxide silane suspension A and Span80 were stirred at 36 °C and 700 r / min for 1 min to obtain oil phase B; (3) Take another clean container, add PEG-2000, deionized water, and PEG-2000, heat and maintain the temperature at 36 °C, and stir at 700 rpm for 2 min to obtain a uniform aqueous phase C. (4) Keeping the temperature and stirring speed constant, continue stirring the oil phase B and the water phase C, and add the oil phase B to the water phase C at the same time. The addition time is 5 min, and then emulsify at a stirring speed of 2200 r / min for 1.5 h to obtain emulsion D; (5) Add the silicone acrylic emulsion to emulsion D for 2 min and stir at 36 °C and 700 r / min for 8 min to obtain a high fluorine-containing silane emulsion.

[0036] Example 3 A high-fluorine-containing silane emulsion, the raw materials of which include, by weight: 2.8 parts of emulsifier, 0.8 parts of polyethylene glycol, 2.5 parts of silicone acrylic emulsion, 13.4 parts of water, 78 parts of silane, 2.5 parts of nano zinc oxide; In the emulsifier, Span80 1.1 parts, Peregal O 1.7 parts; Among the silanes, 39 parts of 1H,1H,2H,2H-perfluorooctyltriethoxysilane and 39 parts of isooctyltriethoxysilane were used.

[0037] The preparation method of high fluorine-containing silane emulsion comprises: (1) 1H,1H,2H,2H-perfluorooctyltriethoxysilane, isooctyltriethoxysilane and nano zinc oxide were added to a container, heated and maintained at 36 °C, and stirred at 2400 r / min for 2 h to obtain modified nano zinc oxide silane suspension A; (2) Nano-zinc oxide silane suspension A and Span80 were mixed uniformly at 36 °C and 750 r / min for 1 min to obtain oil phase B; (3) Take another clean container, add PEG-2000, deionized water, and PEG-2000, heat and maintain the temperature at 36 °C, and stir at 750 rpm for 2 min to obtain a uniform aqueous phase C. (4) Keeping the temperature and stirring speed constant, continue stirring the oil phase B and the water phase C, and add the oil phase B to the water phase C at the same time. The addition time is 10 min, and then emulsify at a stirring speed of 2400 r / min for 1.5 h to obtain emulsion D; (5) Add the silicone acrylic emulsion to emulsion D for 3 min and stir at 36 °C and 750 r / min for 8 min to obtain a high fluorine-containing silane emulsion.

[0038] Comparative Example 1 Compared with Example 1, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, silicone acrylic emulsion and nano zinc oxide were removed, and the material composition was 60 parts of isooctyltriethoxysilane, 6.4 parts of Span80, 1.6 parts of peregal O, 31 parts of deionized water and 1 part of PEG2000.

[0039] The preparation method is as follows: (1) Weigh isooctyltriethoxysilane and Span 80 into a clean container; heat the mixture in a water bath, maintain the temperature at 35 °C, and stir with a magnetic stirrer at 700 rpm for 2 min; (2) Weigh PEG-0 and PEG 2000, add them to another clean container, and then add the remaining deionized water; heat the mixture in a water bath, maintain the temperature at 35 °C, and stir it with a magnetic stirrer at 700 r / min for 2 min; (3) Keep the water bath temperature and magnetic stirrer speed constant, and slowly add the oil phase to the water phase. The entire addition process should be controlled within 5 minutes.

[0040] (4) After the addition of the aqueous phase is completed, continue to keep the water bath heating, increase the speed of the magnetic stirrer to 2000 r / min, and continue stirring for 4 h.

[0041] Comparative Example 2 Compared with Example 1, nano zinc oxide and silicone acrylic emulsion were removed, and the rest were the same as Example 1.

[0042] Comparative Example 3 Compared with Example 1, the material composition is 60 g of 1H,1H,2H,2H-perfluorooctyltriethoxysilane and 20 g of isooctyltriethoxysilane, and the rest are the same as in Example 1.

[0043] Comparative Example 4 A method for preparing an octyl fluorine-containing silicone resin emulsion for concrete surface protection comprises the following steps: (1) Weigh 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane, isooctyltriethoxysilane, and Span80 in proportion and add them to a container. Heat and maintain the temperature at 40 °C and stir at 800 r / min for 5 min to prepare a uniform oil phase A. (2) Take another clean container, add proportionally weighed amounts of Perchlorate O, deionized water, PEG2000, and defoaming agent, heat and maintain the temperature at 40 °C, and stir at 700 r / min for 5 min to prepare a uniform aqueous phase B; (3) Keeping the temperature and stirring speed constant, add the oil phase A to the water phase B at a constant rate, and keep the addition time at 10 min to obtain emulsion C; (4) Keeping the temperature and stirring speed constant, add the silicone acrylic emulsion to emulsion C at a uniform speed, and maintain the addition time at 8 minutes.

[0044] (5) Keeping the temperature constant, stirring at a high speed of 2200 r / min for 4.5 h and then stopping, an octyl fluorinated silicone resin emulsion for concrete surface protection is obtained; (6) Store the emulsion in a clean container and seal it tightly.

[0045] The mass ratio of the materials in each step is 6 parts of 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 18 parts of isooctyltriethoxysilane, 0.44 parts of Span80, 0.76 parts of peregal O, 10.4 parts of deionized water, 0.2 parts of PEG2000, 0.2 parts of silicone defoamer (AFE-1410), and 4 parts of silicone acrylic emulsion.

[0046] According to the method in GBT 17671-2021, a 70.7 mm cubic mortar specimen was prepared as the concrete matrix. One of the sides was selected and the mortar was heated to 300 g / m 2 Apply once on the substrate surface.

[0047] Referring to the silane emulsion performance test method in T / CCES12-2020, the water absorption rate and penetration depth of the emulsions prepared in Examples 1 to 3 and Comparative Examples 1 to 2 and 4 were tested, and the surface contact angle was tested using a JC-2000 contact angle meter.

[0048] To test whether the nano-zinc oxide in the hydrophobic coating possesses photocatalytic activity, enabling self-cleaning, a photocatalytic test was designed. The hydrophobic coating on the mortar surface of Examples 1-3 was scraped off to obtain a powder. The powder was mixed with a 12.5 mg / L methyl orange solution at a ratio of 1 g / L and then exposed to sunlight for 4 hours. By measuring the change in absorbance of the methyl orange solution in the 400-500 nm range before and after illumination, it was possible to detect whether the methyl orange solution decomposed, thereby verifying the coating's photocatalytic self-cleaning function.

[0049] The test results of the emulsions prepared in Examples 1 to 3 and Comparative Examples 1 to 2 and 4 are shown in Table 1. Figures 1 to 3 shown.

[0050] Table 1 Test results of the emulsions prepared in Examples 1 to 3 and Comparative Examples 1 to 2 and 4

[0051] Figure 1The comparison diagram of the high fluorine-containing silane emulsion prepared in Example 1 and the isooctylsilane emulsion prepared in the prior art (Comparative Example 1) after coating shows that the high fluorine-containing silane emulsion prepared in Example 1 is mixed and adjusted with the proportion of 1H,1H,2H,2H-perfluorooctyltriethoxysilane, which increases the viscosity of the emulsion after coating (such as Figure 1 As shown in the figure, the loss due to sagging is small, and the coating can be completed in one time with a small coating amount, but the thickness of the hydrophobic layer formed is about 1.5 times that of ordinary emulsion.

[0052] Figure 2 is the contact angle of the emulsion obtained in Examples 1 to 3 and Comparative Examples 1 to 2 and 4, Figure 2 It can be seen that the contact angles of the high-fluorine-containing silane emulsion provided by the present invention on the mortar specimens are all greater than 130°. Compared with Comparative Example 1, the surface contact angles of Examples 1 to 3 increased by about 10°, effectively improving the hydrophobic effect. In Comparative Example 4, the surface contact angle was only greater than 100°. Compared with Comparative Example 4, it increased by about 30°.

[0053] Figure 3 The penetration depths of the emulsions prepared in Examples 1 to 3 and Comparative Examples 1 to 2 and 4 are shown in Table 1. 2 At the coating rate, the silanes in Examples 1-3 penetrated deeper, forming a thicker hydrophobic layer. Compared to Comparative Example 1, the penetration depth of Examples 1-3 was approximately 1.5 times greater, effectively increasing the penetration depth. Compared to the emulsion in Comparative Example 4, which exhibited better adhesion, the penetration depth was slightly improved.

[0054] Figure 4 The results of the photocatalytic test of the coatings of Examples 1 to 3 are the changes in the absorbance of the methyl orange solution before and after illumination. Figure 4 As can be seen in the figure, at a wavelength of 463 nm, the absorbance of the methyl orange solution without the hydrophobic coating decreased by only 0.02 after illumination compared to before illumination, indicating that the ultraviolet intensity of sunlight is limited and the methyl orange hardly decomposes. However, when the methyl orange solution contained the hydrophobic coating, the absorbance of the methyl orange solution decreased by 0.26 after illumination compared to the sample without the hydrophobic coating. This indicates that the nano-zinc oxide contained in the hydrophobic coating powder has a significant photocatalytic effect, and the generated active oxygen decomposes the methyl orange, verifying the coating's photocatalytic self-cleaning properties, which can oxidize and decompose organic pollutants, protect the coating's hydrophobicity, and maintain a clean and tidy substrate surface.

[0055] Compared with the emulsion of the present invention, Comparative Example 2 does not contain nano-zinc oxide and silicone-acrylic emulsion, resulting in poor emulsion stability. However, compared with Comparative Example 1, the high silane content and the co-doping of 1H,1H,2H,2H-perfluorooctyltriethoxysilane give it a higher viscosity after coating. The fluorine-containing functional groups have lower surface energy than the methyl functional groups contained in isooctyltriethoxysilane, resulting in a stronger hydrophobic effect. As a result, the water absorption rate, penetration depth, and surface contact angle of Comparative Example 2 are all greater than those of Comparative Example 1.

[0056] In Examples 1-3, building on the emulsion foundation of Comparative Example 2, a nano-zinc oxide-silicone acrylic emulsion system was employed. This significantly enhanced the emulsion's stability while retaining its original advantages. Furthermore, after coating, a layer of hydrophobic nano-zinc oxide particles firmly adhered to the substrate surface, increasing surface roughness and enhancing hydrophobicity while also maintaining photocatalytic activity and achieving self-cleaning properties.

[0057] Compared with the emulsion of the present invention, in Comparative Example 3, the ratio of the two silanes is changed, which causes the balance of the emulsion system to be destroyed and the emulsion cannot be formed.

[0058] Compared with the emulsion of the present invention, Comparative Example 4 contains a low silane content. In order to take into account the stability of the emulsion, more film-forming silicone-acrylic emulsion is added. Although it can maintain a large adhesion after coating, the silane content in the emulsion is relatively small, resulting in a larger coating amount than the emulsion of the present invention to achieve a stronger penetration depth and surface contact angle. At the same time, it contains more film-forming silicone-acrylic emulsion, which has a sealing effect on the pores on the concrete surface. Although it has a small water absorption rate, it is not conducive to the diffusion of moisture inside the concrete, thereby affecting the "breathability" of the concrete.

[0059] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A high fluorine-containing silane emulsion, characterized in that: The raw materials include by weight: 2.5-3.0 parts of emulsifier, 0.5-1 part of polyethylene glycol, 2-3 parts of silicone acrylic emulsion, 12-16 parts of water, 74-81 parts of silane; 2-3 parts of nano zinc oxide; Wherein, the emulsifier consists of peregal O and Span80; The silane consists of 1H,1H,2H,2H-perfluorooctyltriethoxysilane and isooctyltriethoxysilane.

2. The high fluorine-containing silane emulsion according to claim 1, wherein The mass ratio of peregal O and Span80 is (1.5-2):1; Alternatively, the mass ratio of 1H,1H,2H,2H-perfluorooctyltriethoxysilane to isooctyltriethoxysilane is 1:

1.

3. The high fluorine-containing silane emulsion according to claim 1, wherein The polyethylene glycol is PEG2000; Alternatively, the silicone acrylic emulsion is silicone acrylic emulsion BF-400B.

4. The method for preparing the high fluorine-containing silane emulsion according to any one of claims 1 to 3, characterized in that: The steps include: (1) Mixing silane and nano zinc oxide uniformly to obtain modified nano zinc oxide silane suspension A; (2) Mix the nano zinc oxide silane suspension A and Span80 to obtain oil phase B; (3) Mixing chlorpyrifos O, polyethylene glycol, and water to obtain aqueous phase C; (4) Add the oil phase B to the water phase C and emulsify to obtain emulsion D; (5) Add the silicone acrylic emulsion to emulsion D and mix well to obtain a high fluorine-containing silane emulsion.

5. The preparation method according to claim 4, wherein In step (1), the mixing conditions are: stirring at 35-40 °C and 2000-2400 r / min for 2-2.5 h.

6. The preparation method according to claim 4, wherein In step (2), the mixing conditions are: stirring at 35-40°C and 700-800 r / min for 1-2 min.

7. The preparation method according to claim 4, wherein In step (3), the mixing conditions are: stirring at 35-40 °C and 700-800 r / min for 1-2 min.

8. The preparation method according to claim 4, wherein In step (3) and step (4), when the oil phase B is added to the water phase C, the oil phase B and the water phase C are continuously stirred at 35-40°C and 700-800 r / min; the addition time is 5-10 min.

9. The preparation method according to claim 4, wherein In step (5), the mixing conditions are: stirring at 35-40°C and 700-800 r / min for 5-10 minutes.

10. Use of the high-fluorine-containing silane emulsion according to any one of claims 1 to 3 or the high-fluorine-containing silane emulsion prepared by the preparation method according to any one of claims 5 to 9 in concrete structure surface protection projects; The applications include: Apply high fluorine-containing silane emulsion to the concrete surface, apply once, and apply 280~320 g / m 2 .

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