Silica sol and its preparation method, silica sol coatings and porous coatings and glass

Abstract

This invention provides a silica sol and its preparation method, a silica sol coating, a porous coating, and glass. The silica sol comprises an emulsion in a mass ratio of 10-20:25-40:1-6:40-60:0.01-0.1:1-4, an alkoxysilane, a silane coupling agent, a first organic solvent, a catalyst, and water. The emulsion comprises water in a mass ratio of 70-90:0.1-0.25:0.1-0.25:10-30:0.1-1, an emulsifier, an initiator, styrene, and a cationic monomer. This invention also provides a method for preparing the above-mentioned silica sol, a coating made from the silica sol, a porous coating formed by the coating, and glass with the coating. The silica sol provided by this invention has uniform particle size, and after curing, forms a porous coating with uniform pore size. Glass with this porous coating has high hardness, good wear resistance and aging resistance, and excellent optical properties.

Description

Technical Field

[0001] This invention relates to the field of functional coating manufacturing technology, and in particular to a silica sol and its preparation method, silica sol coatings and porous coatings and glass. Background Technology

[0002] Currently, automotive glass is generally coated with functional coatings, such as a silver layer for heat insulation and sun protection, and a TCO layer for panoramic sunroof displays. Outside these functional layers, a protective coating is needed to isolate oxygen and provide insulation. Simultaneously, while fulfilling these functions, the coated glass must also meet standards for optical performance, mechanical properties, and weather resistance. Porous silica coatings can achieve these technical objectives.

[0003] Existing porous silica coating technologies, such as the Chinese patent CN113508098A which discloses a method for preparing a vehicle glass plate with reduced emissivity and reflectivity, are as follows: The coating in this invention consists of an emissivity-reducing coating (10) and a reflectivity-reducing coating (20). The coating (10) contains at least one layer based on transparent conductive oxide (TCO), and the coating (20) is an anti-reflective coating based on nanoporous silica. This porous silica coating is prepared by using a sol-gel method to prepare a precursor sol, which is then mixed with a pore-forming agent to prepare a coating solution. The solution is then applied using a wet coating method (dipping, spin coating, flow coating, spray coating), followed by high-temperature (≥400℃) curing to remove the pore-forming agent, thus obtaining the porous coating. This invention's coating can significantly reduce the reflectivity of the coated glass, achieving an 8° R² (radius intensity reduction). L Value less than 2%, R at 60° L The value is less than 4%. This invention explains the principle of the porous coating preparation process, but does not disclose the specific formula and preparation process. Furthermore, it does not describe the optical properties, mechanical properties, or aging resistance of the coating. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a silica sol and its preparation method, a silica sol coating, a porous coating, and glass.

[0005] To achieve the above objectives, the present invention provides a silica sol, the raw materials of which include an emulsion, an alkoxysilane, a silane coupling agent, a first organic solvent, a catalyst, and water in a mass ratio of 10-20:25-40:1-6:40-60:0.01-0.1:1-4;

[0006] The raw materials of the emulsion include water, emulsifier, initiator, styrene and cationic monomer in a mass ratio of 70-90:0.1-0.25:0.1-0.25:10-30:0.1-1.

[0007] In the raw materials of the above emulsion, water can be 70-90 parts by mass; the emulsifier can be 0.1-0.25 parts, for example, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, etc., and any two of the above specific values ​​as endpoints; the initiator can be 0.1-0.25 parts, for example, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, etc., and any two of the above specific values ​​as endpoints; the styrene can be 10-30 parts, for example, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, etc., and any two of the above specific values ​​as endpoints; the cationic monomer can be 0.1-1 part, for example, 0.1 parts, 0.3 parts, 0.5 parts, 0.7 parts, 1.0 parts, etc., and any two of the above specific values ​​as endpoints.

[0008] In some specific embodiments, the raw materials of the emulsion, based on the total weight of the raw materials as 100%, may specifically include 70%-90% water, 0.1%-0.25% emulsifier, 0.1%-0.25% initiator, 10%-30% styrene, and 0.1%-1.0% cationic monomer. The sum of the weights of the above components is 100%.

[0009] Furthermore, the weight percentage of the emulsifier in the raw materials of the emulsion can be a specific value such as 0.1%, 0.15%, 0.2%, 0.25%, or a range with any two of the above specific values ​​as endpoints.

[0010] Furthermore, the weight percentage of the initiator in the raw materials of the emulsion can be a specific value such as 0.1%, 0.15%, 0.2%, 0.25%, or a range with any two of the above specific values ​​as endpoints.

[0011] Furthermore, the weight percentage of styrene in the raw materials of the emulsion can be a specific value such as 10%, 15%, 20%, 25%, 30%, or a range with any two of the above specific values ​​as endpoints.

[0012] Furthermore, the weight percentage of the cationic monomer in the raw materials of the emulsion can be a specific value such as 0.1%, 0.3%, 0.5%, 0.7%, 1.0%, or a range with any two of the above specific values ​​as endpoints.

[0013] In the aforementioned silica sol, by controlling the amount of styrene added to the emulsion raw materials, the particle size of the polymer product and the pore size in the prepared silica sol network can be adjusted, thereby adjusting the pore size, mechanical properties (hardness), wear resistance, and aging resistance of the coating formed by the curing of the silica sol.

[0014] In the aforementioned silica sol, the emulsifier may include one or a combination of two or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, dodecyl ammonium chloride, hexadecyltrimethylammonium bromide, and hexadecylpyridine bromide.

[0015] In the aforementioned silica sol, the initiator may include one or a combination of two or more of the following: ammonium persulfate, potassium persulfate, sodium persulfate, azobisisopropylimidazoline hydrochloride, azobisisobutyramidine hydrochloride, and azobiscyanopentanoic acid.

[0016] In the aforementioned silica sol, by introducing cationic monomers into the polystyrene chain segments, the polystyrene polymer can be transformed from being electrically neutral to being positively charged. The resulting cationic polystyrene can then combine with the negatively charged silica sol through electrostatic adsorption, thereby improving their compatibility.

[0017] The cationic monomer may include quaternary ammonium chloride. Specifically, the cationic monomer may include one or a combination of two or more of the following quaternary ammonium chlorides: methacryloyloxyethyltrimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, methacrylamidopropyltrimethylammonium chloride, acrylamidopropyltrimethylammonium chloride, and dimethyldiallylammonium chloride.

[0018] In the aforementioned silica sol, the cationic polystyrene acts as a pore-forming agent. High-temperature treatment removes the cationic polystyrene, allowing it to form pores in the silica sol coating. Compared to conventional electrically neutral polystyrene, the aforementioned cationic polystyrene polymer is positively charged, enabling it to bind with the negatively charged silica sol, resulting in good compatibility. Due to the good compatibility between cationic polystyrene and silica sol, the silica sol particle size distribution in the formulated coating is uniform, leading to uniform pore size in the coating and improved film hardness, wear resistance, and aging resistance.

[0019] In the above-mentioned silica sol, the alkoxysilane can be formed by hydrolytic condensation. The structural formula of the alkoxysilane can be: R 2 4-n Si(OR 1 ) n Where n is one of 1, 2, 3 or 4, and R 1 Selected from alkyl groups, R 2 It is a non-hydrolyzable organic functional group; furthermore, R 2 It is an alkyl or phenyl group; furthermore, R 1 It is methyl or ethyl, R 2 It is one of methyl, ethyl, or phenyl. Understandably, when n = 4, the alkoxysilane does not contain R. 2 .

[0020] According to a specific embodiment of the present invention, the alkoxysilane may specifically include one or a combination of two or more of tetramethyl orthosilicate, tetraethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane.

[0021] In the aforementioned silica sol, the addition of a silane coupling agent improves the adhesion of the coating to the glass substrate surface, while simultaneously reducing the surface roughness and making the coating surface smoother. The silane coupling agent may include γ-glycidoxypropyltrimethoxysilane (KH560) and / or γ-methacryloyloxypropyltrimethoxysilane (KH570).

[0022] In the aforementioned silica sol, the catalyst can be an acidic catalyst, such as an inorganic acid. Specifically, the catalyst may include hydrochloric acid and / or nitric acid. Compared to alkaline catalysts, coatings made from silica sol prepared with acidic catalysts exhibit higher wear resistance.

[0023] During the reaction to form silica sol, under the action of a catalyst, the raw materials in the silica sol can undergo dehydration condensation reaction in the sol-gel environment to first generate linear polymers, and then further generate network structures through cross-linking reaction to obtain silica sol with excellent wear resistance.

[0024] This invention has found that excessive catalyst dosage leads to an overemphasis on the Si-OH bonds formed by the hydrolysis of alkoxysilanes, resulting in particle agglomerates. The condensation process tends to occur within the particles rather than between them, leading to a decrease in coating density. This invention addresses this by controlling the catalyst dosage to obtain a dense silica sol film. Further high-temperature curing of the silica sol allows it to form a coating, increasing structural density and improving the coating's mechanical properties.

[0025] In the above-mentioned silica sol, the mass ratio of the catalyst to the alkoxysilane is generally controlled to be 0.01-0.1:25-40.

[0026] In the aforementioned silica sol, the first organic solvent includes ethanol and / or isopropanol.

[0027] In some specific embodiments, the mass ratio of the emulsion, alkoxysilane, silane coupling agent, first organic solvent, catalyst and water can be 10-20:25-40:1-6:40-60:0.01-0.1:1-4.

[0028] In the silica sol of the present invention, the mass ratio of the emulsion to the alkoxysilane can be 10-20:25-40; further, the mass ratio of the emulsion to the alkoxysilane can be 10:15-30, for example, specific values ​​such as 10:15, 10:18, 10:20, 10:25, 10:30, and a range with any two of the above specific values ​​as endpoints.

[0029] In the silica sol of the present invention, the mass ratio of the silane coupling agent to the alkoxysilane can be 1-6:25-40. Further, the mass ratio of the silane coupling agent to the alkoxysilane can be 12-60:150-300.

[0030] In the silica sol of the present invention, the mass ratio of the catalyst to the alkoxysilane can be 0.01-0.1:25-40. Further, the mass ratio of the catalyst to the alkoxysilane can be 0.25:150-300.

[0031] In the silica sol of the present invention, the mass ratio of the first organic solvent to the alkoxysilane can be 40-60:25-40. Further, the mass ratio of the first organic solvent to the alkoxysilane can be 300-520:150-300.

[0032] In the silica sol of the present invention, the mass ratio of water to alkoxysilane can be 1-4:25-40. Further, the mass ratio of water to alkoxysilane can be 6-20:150-300.

[0033] This invention provides a method for preparing the above-mentioned silica sol, the method comprising:

[0034] S1. The raw materials for forming an emulsion are mixed with water, emulsifier, initiator, styrene monomer, and cationic monomer, and the raw materials of the emulsion undergo a polymerization reaction to obtain an emulsion;

[0035] S2. An emulsion, alkoxysilane, silane coupling agent, first organic solvent, catalyst and water in a mass ratio of 10-20:25-40:1-6:40-60:0.01-0.1:1-4 are mixed and reacted to obtain silica sol.

[0036] In the above method for preparing silica sol, in step S1, the polymerization reaction is generally a free radical polymerization reaction. The temperature of the polymerization reaction can be controlled between 75℃ and 85℃, for example, specific values ​​such as 75℃, 80℃, and 85℃, or a range with any two of the above specific values ​​as endpoints; the time of the polymerization reaction can be controlled between 3h and 5h, for example, specific values ​​such as 3h, 4h, and 5h, or a range with any two of the above specific values ​​as endpoints.

[0037] In the above-described method for preparing silica sol, the polymer generated by the polymerization reaction in S1 includes cationic polystyrene. Correspondingly, the emulsion obtained in S1 contains cationic polystyrene, and this emulsion can be considered a cationic polystyrene emulsion. In the cationic polystyrene, the cationic monomer can be grafted onto the side chains of polystyrene or embedded in the main chain of polystyrene. In some specific embodiments, the cationic polystyrene can be spherical particles with a particle size of 40nm-80nm, for example, specific values ​​such as 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, etc., and a range with any two of the above specific values ​​as endpoints.

[0038] According to a specific embodiment of the present invention, the specific process of S1 may be as follows: water, emulsifier and initiator are uniformly mixed, then styrene and cationic monomer are added, the temperature is raised to 75℃-85℃ to carry out free radical polymerization reaction, the reaction time is 3h-5h, and after the reaction is completed, the mixture is cooled to room temperature to obtain an emulsion containing cationic polystyrene.

[0039] In the above method for preparing silica sol, the emulsion added in S2 is the untreated emulsion obtained directly in S1. The mass of the emulsion in S2 can be calculated based on the mass of the emulsion obtained directly in S1.

[0040] In the above method for preparing silica sol, the reaction in S2 is a reaction in which alkoxysilanes are hydrolyzed and polycondensed to form silica sol. The reaction temperature can be controlled between 50℃ and 70℃, for example, specific values ​​such as 50℃, 55℃, 60℃, 65℃, and 70℃, and a range with any two of the above specific values ​​as endpoints; the reaction time can be controlled between 4h and 6h, for example, specific values ​​such as 4h, 4.5h, 5h, 5.5h, and 6h, and a range with any two of the above specific values ​​as endpoints.

[0041] In the above-described method for preparing silica sol, the silica sol obtained in step S2 contains molecules with different degrees of polymerization. By controlling the ratio of alkoxysilane to silane coupling agent, the silica sol can have a suitable molecular structure and hydroxyl distribution, thereby obtaining a silica sol that can bond firmly to the glass surface and also has good compatibility with various additives in coatings. According to a specific embodiment of the present invention, the mass ratio of alkoxysilane to silane coupling agent can be controlled to 25-40:1-6, and more preferably to 5-15:1.

[0042] According to a specific embodiment of the present invention, the main components of the silica sol may include: silica sol molecules generated by the reaction of alkoxysilane with a silane coupling agent, cationic polystyrene, and a first organic solvent. The reaction between the alkoxysilane and the silane coupling agent is generally a sol-gel reaction.

[0043] The present invention also provides a silica sol coating, which includes the above-mentioned silica sol, an additive, and a second organic solvent; wherein the mass ratio of the silica sol, the additive, and the second organic solvent is 25-35:2-5:60-70.

[0044] The silica sol contained in the above coating is the untreated silica sol directly obtained in step S2 of the silica sol preparation method described above. The mass of the silica sol in the coating can be calculated based on the mass of the silica sol obtained in step S2 of the silica sol preparation method.

[0045] In the aforementioned silica sol coating, the positively charged cationic polystyrene combines with the negatively charged silica sol, which is beneficial for the uniform particle size distribution of the silica sol in the coating and the uniform pore size in the cured coating, thereby improving the hardness, wear resistance and aging resistance of the coating.

[0046] In the aforementioned silica sol coating, the additives can regulate the evaporation rate of the organic solvent, adjust the coating formation process, and promote coating formation. The additives may include propylene glycol methyl ether acetate and / or diethylene glycol ethyl ether.

[0047] In the aforementioned silica sol coating, the second organic solvent includes ethanol and / or isopropanol. In some specific embodiments, the first organic solvent and the second solvent may be the same or different.

[0048] According to specific embodiments of the present invention, the solid content (the mass percentage of solids in the coating) of the aforementioned silica sol coating can be adjusted according to actual conditions. The solid content can be measured by heating at 150°C for 2 hours and calculating the proportion of the remaining solid mass to the total mass of the coating. By adjusting the solid content of the silica sol coating, the second organic solvent can have a suitable evaporation rate, thereby obtaining a coating with ideal performance. Specifically, the solid content can be adjusted by regulating the amount of the second organic solvent added, and additives can be added to assist in controlling the evaporation rate of the second organic solvent, thereby obtaining a coating with better performance. In some specific embodiments, the solid content of the silica sol coating can be 1%-20%.

[0049] The present invention also provides a porous coating, which is obtained by drying the above-mentioned silica sol coating and then subjecting it to curing and tempering treatments in sequence.

[0050] According to a specific embodiment of the present invention, the porous coating has uniformly distributed pores, each pore being of uniform size. The pores in the porous coating are formed by calcining cationic polystyrene spheres during the curing process. The porous structure in the porous coating can lower the refractive index of the coating surface, giving the coating an anti-reflective effect. Applying this porous coating to transparent substrates such as glass can improve the visible light transmittance of the substrate, reduce reflectivity and haze; and, without affecting the original optical properties of the substrate (visible light transmittance, reflectivity, haze, etc.), the porous coating can provide air isolation and insulation, and possesses high hardness, wear resistance, and aging resistance.

[0051] In some specific embodiments, the pore size in the coating is 40nm-80nm.

[0052] According to specific embodiments of the present invention, the cationic polystyrene contained in the emulsion used as a silica sol raw material has a small particle size, which is beneficial for the formation of a thin porous coating after the silica sol coating is cured. In some specific embodiments, the thickness of the porous coating can be 100 nm to 500 nm.

[0053] According to a specific embodiment of the present invention, the silica sol coating is formed by curing and tempering. Tempering removes cationic polystyrene from the coating, creating pores in the film where cationic polystyrene was originally present, thus obtaining a coating with a porous structure. The curing temperature can be controlled between 150℃ and 250℃, for example, specific values ​​such as 150℃, 170℃, 190℃, 200℃, 210℃, 230℃, and 250℃, and any two of these specific values ​​as endpoints; the curing time can be controlled between 5 min and 10 min, for example, specific values ​​such as 5 min, 6 min, 7 min, 8 min, 9 min, and 10 min, and any two of these specific values ​​as endpoints. The tempering temperature can be controlled between 650℃ and 750℃, for example, specific values ​​such as 650℃, 700℃, and 750℃, and a range with any two of the above specific values ​​as endpoints; the tempering temperature can be controlled between 5min and 10min, for example, specific values ​​such as 5min, 6min, 7min, 8min, 9min, and 10min, and a range with any two of the above specific values ​​as endpoints.

[0054] According to a specific embodiment of the present invention, the method for preparing the porous coating may specifically include: applying the above-mentioned silica sol coating onto the surface of a substrate (such as a glass substrate), drying, curing at 150℃-250℃ for 5 min-10 min, and tempering at 650℃-750℃ for 5 min-10 min to obtain a coating having a porous structure.

[0055] The present invention also provides a glass comprising a glass substrate and a coating disposed on the surface of the glass substrate, the coating comprising the porous coating provided by the present invention described above.

[0056] In the aforementioned glass, the thickness of the porous coating can be 100nm-500nm, for example, it can be a specific value such as 100nm, 200nm, 300nm, 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, 370nm, 380nm, 390nm, 400nm, 500nm, etc., or a range with any two of the above specific values ​​as endpoints.

[0057] According to a specific embodiment of the present invention, the coating can be in direct contact with the surface of the glass substrate, for example, the coating can be directly applied to the surface of the glass substrate; or, the coating can be in indirect contact with the glass substrate, with a functional layer structure sandwiched between them, such as one or more combinations of a transparent conductive layer and a heat insulation layer. The transparent conductive layer can be disposed between the coating and the glass substrate, and the heat insulation layer can be disposed between the coating and the glass substrate. Specifically, the transparent conductive layer can be an ITO (indium tin oxide) layer, and the heat insulation layer can be an Ag layer.

[0058] In the aforementioned glass, the visible light transmittance of the glass substrate is greater than or equal to 70%. The glass substrate may include one or a combination of two or more of soda-lime glass, aluminosilicate glass, borosilicate glass, and lithium aluminosilicate glass. The type and color of the glass substrate can be selected according to actual application requirements. In some specific embodiments, the glass substrate may include ultra-clear glass, wherein the visible light transmittance of the ultra-clear glass can reach greater than or equal to 90%.

[0059] In the above-mentioned glass, the glass substrate can be a glass substrate with a refractive power of less than or equal to ≤110 mdp, and the glass substrate has excellent optical quality.

[0060] According to a specific embodiment of the present invention, the method for preparing the above-mentioned glass may include:

[0061] A silica sol coating is applied to the surface of a glass substrate. After the silica sol coating on the glass substrate surface dries, the glass substrate is cured and tempered to obtain the glass.

[0062] In the above-mentioned glass preparation method, the coating method can adopt a conventional coating process, such as spraying, roller coating, dip coating, spin coating, etc.

[0063] In the above glass preparation method, the curing temperature can be 150℃-250℃, and the curing time can be 5min-10min.

[0064] In the above glass preparation method, the tempering temperature can be 650℃-750℃, and the tempering time can be 5min-10min.

[0065] According to a specific embodiment of the present invention, the glass described above can be automotive glass.

[0066] When the above-mentioned glass is used as automotive glass, it has high visible light transmittance, low reflectivity and haze, and good mechanical properties, wear resistance and aging resistance.

[0067] In some specific embodiments, when the glass is composed of a glass substrate and a coating (excluding other functional layer structures), the transmittance of the glass for visible light in the 380nm-780nm range can reach more than 89% (when the transmittance of the glass substrate for visible light in the 380nm-780nm range is 87%), the haze of the glass can be controlled below 0.3%, the reflectance of the glass for visible light in the 360nm-780nm range can be controlled below 5.6%, the hardness of the glass can reach 4H, the haze difference before and after the wear resistance test can be controlled below 1.5%, and there are no cracks in the appearance after the xenon lamp aging test. The test conditions for the wear resistance test can be as follows: the coating is bonded to the substrate to form the test sample, the haze of the test sample before the test is recorded, the test sample is placed on the plane wear tester with the coating facing upward, the test pressure is 4.5N, and the plane wear test is performed for 500 revolutions. The haze H1 is obtained by testing the area of ​​the test sample that has not undergone the wear resistance test, and the haze H2 is obtained by testing the area that has undergone the wear resistance test. The haze difference before and after the test is equal to H2 - H1.

[0068] The coating provided by this invention is heat-resistant, capable of withstanding not only the coating curing process (150℃-250℃) but also the high-temperature treatment process (650℃-750℃) during automotive glass bending and forming. Therefore, the glass provided by this invention combines the coating curing process and the high-temperature stage of glass bending and forming, allowing both to occur simultaneously. This saves on separate high-temperature coating curing steps, simplifies the production process, reduces energy consumption, and offers significant economic and environmental benefits.

[0069] According to a specific embodiment of the present invention, the method for preparing the glass includes: applying a coating to the surface of a glass substrate, bending the glass substrate, simultaneously curing and tempering the coating to form a coating layer, thereby obtaining the glass.

[0070] The beneficial effects of this invention include:

[0071] 1. This invention prepares silica sol using the sol-gel method. The prepared silica sol has a suitable molecular structure and hydroxyl distribution, which can not only bond firmly to the glass surface, but also has good compatibility with various additives in silica sol coatings.

[0072] 2. The emulsion prepared by this invention contains cationic polystyrene microspheres. By adjusting the emulsion preparation process conditions, the particle size and charge density of the synthesized microspheres can be adjusted, resulting in microspheres with good monodispersity. This makes the coating effect formed by the silica sol made from the emulsion adjustable. Furthermore, by first preparing cationic polystyrene microspheres and then using the microspheres as raw materials to chemically react with alkoxysilanes, silane coupling agents, catalysts, solvents, and water to prepare silica sols and coatings, the preparation process can be simplified, reaction vessels can be saved, production efficiency can be improved, and the coating application effect is better.

[0073] 3. This invention introduces cationic monomers into the polystyrene chain segment during the polymer emulsion preparation process, transforming the electrically neutral polystyrene polymer into positively charged cationic polystyrene. This cationic polystyrene can bind with anionic silica sol through electrostatic attraction, exhibiting good compatibility. The resulting coating exhibits uniform silica sol particle size distribution and uniform pore size, thus improving the coating's hardness, wear resistance, and aging resistance.

[0074] 4. The silica sol coating preparation process of this invention enables continuous production, simplifying the process flow and reducing production costs. Furthermore, the raw materials, additives, and solvents used are inexpensive, reducing raw material costs and improving the cost-effectiveness of the coating.

[0075] 5. The porous coating glass provided by the present invention has excellent optical properties, mechanical properties and weather resistance when used as coated automotive glass. Attached Figure Description

[0076] Figure 1 The image shown is a TEM image of the emulsion prepared in Example 1.

[0077] Figure 2 The diagram shows the structural features of the glass in Examples 1, 4, 5, 6, Comparative Examples 1, 2, and 3.

[0078] Figure 3 This is a schematic diagram of the coating structure in the glass of Examples 1, 2, 3, 4, 5, 6, Comparative Examples 1, 2, and 3.

[0079] Figure 4 This is a schematic diagram of the glass structure in Example 2.

[0080] Figure 5This is a schematic diagram of the glass structure in Example 3.

[0081] Symbol Explanation

[0082] Glass substrate 1, coating 2, Ag layer 3, ITO layer 4. Detailed Implementation

[0083] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0084] Example 1

[0085] This embodiment provides a silica sol coating, the preparation method of which includes the following steps:

[0086] 1. Preparation of emulsion:

[0087] Using a three-necked flask equipped with a thermometer and a stirrer, add 0.2 g of emulsifier cetyltrimethylammonium bromide, 0.2 g of initiator azobisisopropylimidazoline hydrochloride, and 79.1 g of pure water. Start the stirrer, then add 20.0 g of styrene and 0.5 g of methacryloyloxyethyltrimethylammonium chloride to the flask. Stir until homogeneous and heat to 85°C. After reacting for 3 hours, cool to 50°C to obtain an emulsion.

[0088] This emulsion contains cationic polystyrene. Figure 1 The image shows a SEM image of the emulsion. The emulsion contains microspheres (which are cationic polystyrene) with a particle size of about 50 nm.

[0089] 2. Preparation of silica sol:

[0090] Add 150g of tetraethyl orthosilicate, 30g of KH560, and 314g of ethanol to the entire emulsion obtained in step 1 (directly obtained from step 1 without any other treatment; this applies to the following examples and comparative examples), and start stirring. Dissolve 0.25g of nitric acid in 6g of water to obtain a catalyst solution, and add the catalyst solution to a three-necked flask. Heat to 50°C, maintain this temperature for 6 hours, then cool to room temperature; the discharged product is silica sol.

[0091] 3. Preparation of silica sol coatings:

[0092] Add 52g of propylene glycol methyl ether acetate and 1088g of ethanol to all the silica sol solution in step 2 (obtained directly from step 2 without any other treatment, as is the case in the following examples and comparative examples), and mix well to obtain a stable silica sol coating.

[0093] This embodiment also provides a type of glass, such as... Figure 2As shown, the glass includes a glass substrate 1 and a coating 2, with the coating 2 covering the surface of the glass substrate 1. The coating 2 is a porous coating made of silica sol, prepared using the silica sol coating of this embodiment. Figure 3 As shown, coating 2 has a porous structure with uniform pore size and the pores are evenly distributed throughout the coating. In this embodiment, the pore size in coating 2 is 40nm-80nm.

[0094] The glass preparation method of this embodiment includes the following steps:

[0095] The original glass sheet (as the glass substrate) is cleaned and dried. A conventional spraying process is used to coat the original glass sheet with silica sol coating. After the coating on the surface of the glass substrate dries, the glass substrate is cured at 150°C for 10 minutes and then tempered at 750°C for 5 minutes (during which the coating forms a silica sol coating with a porous structure). After cooling, the glass is obtained. This glass can be used as a porous silica sol coated automotive glass.

[0096] Example 2

[0097] This embodiment provides a type of glass, such as... Figure 4 As shown, the glass includes a glass substrate 1, an Ag layer 3, and a coating 2, with the Ag layer 3 located between the coating 2 and the glass substrate 1. The coating 2 is a porous coating made of silica sol, prepared from the silica sol coating of Example 1. Figure 3 As shown, coating 2 has a porous structure with uniform pore size and the pores are evenly distributed throughout the coating. In this embodiment, the pore size in coating 2 is 40nm-80nm.

[0098] The glass preparation method of this embodiment includes the following steps:

[0099] (1) Clean and dry the glass substrate, and use magnetron sputtering to deposit Ag layer 3 on the glass substrate to obtain coated glass.

[0100] (2) Using conventional spraying process, the silica sol coating is applied to the above-mentioned coated glass. After the coating on the surface of the coated glass dries, the coated glass is cured at 150°C for 10 minutes and then tempered at 750°C for 5 minutes (during which the coating forms a silica sol coating with a porous structure). After cooling, the glass is obtained. This glass can be used as a porous silica sol coated automotive glass.

[0101] Example 3

[0102] This embodiment provides a type of glass, such as... Figure 5 As shown, the glass includes a glass substrate 1, an ITO layer 4, and a coating 2, with the ITO layer 4 located between the glass substrate 1 and the coating 2. The coating 2 is a porous coating made of silica sol, prepared from the silica sol coating of Example 1. Figure 3As shown, coating 2 has a porous structure with uniform pore size and the pores are evenly distributed throughout the coating. In this embodiment, the pore size in coating 2 is 40nm-80nm.

[0103] The glass preparation method of this embodiment includes the following steps:

[0104] (1) Clean and dry the glass substrate, and use magnetron sputtering to deposit an ITO layer 4 on the glass substrate to obtain coated glass.

[0105] (2) Using conventional spraying process, the silica sol coating is applied to the above-mentioned coated glass. After the coating on the surface of the coated glass dries, the coated glass is cured at 150°C for 10 minutes and then tempered at 750°C for 5 minutes (during which the coating forms a silica sol coating with a porous structure). After cooling, the glass is obtained. This glass can be used as a porous silica sol coated automotive glass.

[0106] Example 4

[0107] This embodiment provides a silica sol coating, the preparation method of which includes the following steps:

[0108] 1. Preparation of emulsion:

[0109] Using a three-necked flask equipped with a thermometer and a stirrer, add 0.2 g of dodecyl ammonium chloride emulsifier, 0.2 g of azobisisobutyramidine hydrochloride initiator, and 89.1 g of pure water. Start stirring, then add 10.0 g of styrene and 0.5 g of acryloyloxyethyltrimethylammonium chloride to the flask. Stir until homogeneous and heat to 80°C. After reacting for 4 hours, cool to 55°C to obtain an emulsion. The emulsion contains cationic polystyrene microspheres with a particle size of approximately 40 nm.

[0110] 2. Preparation of silica sol:

[0111] Add 150g of methyltriethoxysilane, 30g of KH560, and 314g of ethanol to the entire emulsion from step 1, and start stirring. Dissolve 0.25g of nitric acid in 6g of water to obtain a catalyst solution, and add the catalyst solution to a three-necked flask. Heat to 55°C, maintain the temperature for 5.5h, then cool to room temperature. The discharged product is silica sol.

[0112] 3. Preparation of silica sol coatings:

[0113] Add 52g of propylene glycol methyl ether acetate and 1088g of ethanol to the entire silica sol solution in step 2, and mix well to obtain a stable silica sol coating.

[0114] This embodiment also provides a type of glass, such as... Figure 2As shown, the glass includes a glass substrate 1 and a coating 2, with the coating 2 covering the surface of the glass substrate 1. The coating 2 is a porous coating made of silica sol, prepared using the silica sol coating of this embodiment. Figure 3 As shown, coating 2 has a porous structure with uniform pore size and the pores are evenly distributed throughout the coating. In this embodiment, the pore size in coating 2 is 40nm-80nm.

[0115] The glass preparation method of this embodiment includes the following steps:

[0116] The original glass sheet (as the glass substrate) is cleaned and dried. A conventional spraying process is used to coat the original glass sheet with silica sol coating. After the coating on the surface of the glass substrate dries, the glass substrate is cured at 175℃ for 8 minutes, and then tempered at 700℃ for 7.5 minutes (during which the coating forms a silica sol coating with a porous structure). After cooling, the glass is obtained, which can be used as a porous silica sol coated automotive glass.

[0117] Example 5

[0118] This embodiment provides a silica sol coating, the preparation method of which includes the following steps:

[0119] 1. Preparation of emulsion:

[0120] Using a three-necked flask equipped with a thermometer and a stirrer, add 0.2 g of sodium dodecyl sulfate (emulsifier), 0.2 g of ammonium persulfate (initiator), and 79.1 g of pure water. Start the stirrer, then add 20.0 g of styrene and 0.5 g of methacrylamidopropyltrimethylammonium chloride to the flask. Stir until homogeneous and heat to 75°C. After reacting for 5 hours, cool to 60°C to obtain an emulsion. The emulsion contains cationic polystyrene microspheres with a particle size of approximately 60 nm.

[0121] 2. Preparation of silica sol:

[0122] Add 180g of dimethyldiethoxysilane, 12g of KH570, and 302g of isopropanol to the entire emulsion from step 1, and start stirring. Dissolve 0.25g of hydrochloric acid in 6g of water to obtain a catalyst solution, and add the catalyst solution to a three-necked flask. Heat to 60°C, maintain the temperature for 5 hours, then cool to room temperature. The discharged product is silica sol.

[0123] 3. Preparation of silica sol coatings:

[0124] Add 52g of diethylene glycol ethyl ether and 1088g of isopropanol to the entire silica sol solution in step 2, and mix well to obtain a stable silica sol coating.

[0125] This embodiment also provides a type of glass, such as... Figure 2As shown, the glass includes a glass substrate 1 and a coating 2, with the coating 2 covering the surface of the glass substrate 1. The coating 2 is a porous coating made of silica sol, prepared using the silica sol coating of this embodiment. Figure 3 As shown, coating 2 has a porous structure with uniform pore size and the pores are evenly distributed throughout the coating. In this embodiment, the pore size in coating 2 is 40nm-80nm.

[0126] The glass preparation method of this embodiment includes the following steps:

[0127] The original glass sheet (as the glass substrate) is cleaned and dried. A conventional spraying process is used to coat the original glass sheet with silica sol coating. After the coating on the surface of the glass substrate dries, the glass substrate is cured at 200℃ for 7 minutes, and then tempered at 700℃ for 7.5 minutes (during which the coating forms a silica sol coating with a porous structure). After cooling, the glass is obtained, which can be used as a porous silica sol coated automotive glass.

[0128] Example 6

[0129] This embodiment provides a silica sol coating, the preparation method of which includes the following steps:

[0130] 1. Preparation of emulsion:

[0131] Using a three-necked flask equipped with a thermometer and a stirrer, add 0.2 g of sodium dodecylbenzenesulfonate (emulsifier), 0.2 g of potassium persulfate (initiator), and 79.1 g of pure water. Start the stirrer, then add 20.0 g of styrene and 0.5 g of acrylamidopropyltrimethylammonium chloride to the flask. Stir until homogeneous and heat to 75°C. After reacting for 5 hours, cool to 70°C to obtain an emulsion. The emulsion contains cationic polystyrene microspheres with a particle size of approximately 60 nm.

[0132] 2. Preparation of silica sol:

[0133] Add 300g of phenyltrimethoxysilane, 60g of KH570, and 520g of isopropanol to the entire emulsion from step 1, and start stirring. Dissolve 0.25g of hydrochloric acid in 20g of water to obtain a catalyst solution, and add the catalyst solution to a three-necked flask. Heat to 70°C, maintain the temperature for 4 hours, then cool to room temperature. The discharged product is silica sol.

[0134] 3. Preparation of silica sol coatings:

[0135] Add 130g of diethylene glycol ethyl ether and 1980g of isopropanol to the entire silica sol solution in step 2, and mix thoroughly to obtain a stable silica sol coating.

[0136] This embodiment also provides a type of glass, such as... Figure 2As shown, the glass includes a glass substrate 1 and a coating 2, with the coating 2 covering the surface of the glass substrate 1. The coating 2 is a porous coating made of silica sol, prepared using the silica sol coating of this embodiment. Figure 3 As shown, coating 2 has a porous structure with uniform pore size and the pores are evenly distributed throughout the coating. In this embodiment, the pore size in coating 2 is 40nm-80nm.

[0137] The glass preparation method of this embodiment includes the following steps:

[0138] The original glass sheet (as the glass substrate) is cleaned and dried. A conventional spraying process is used to coat the original glass sheet with silica sol coating. After the coating on the surface of the glass substrate dries, the glass substrate is cured at 250°C for 5 minutes, and then tempered at 650°C for 10 minutes (during which the coating forms a silica sol coating with a porous structure). After cooling, the glass is obtained. This glass can be used as a porous silica sol coated automotive glass.

[0139] Comparative Example 1

[0140] This comparative example provides a silica sol coating, the preparation method of which includes:

[0141] 1. Preparation of emulsion:

[0142] Using a three-necked flask equipped with a thermometer and a stirrer, add 0.2 g of emulsifier cetyltrimethylammonium bromide, 0.2 g of initiator azobisisopropylimidazoline hydrochloride, and 79.6 g of pure water. Start stirring, then add 20.0 g of styrene to the three-necked flask, stir until homogeneous, and heat to 85°C. After reacting for 3 hours, cool to 50°C to obtain an emulsion.

[0143] The emulsion contains polystyrene with a particle size of 85 nm.

[0144] Compared to the emulsion in Example 1, the emulsion raw materials in this comparative example do not contain cationic monomers such as methacryloyloxyethyltrimethylammonium chloride.

[0145] 2. Preparation of silica sol:

[0146] Add 150g tetraethyl orthosilicate, 30g KH560, and 314g ethanol to the entire emulsion from step 1, and start stirring. Dissolve 0.25g nitric acid in 6g water to obtain a catalyst solution, and add the catalyst solution to a three-necked flask. Heat to 50°C, maintain the temperature for 6 hours, then cool to room temperature. The resulting product is silica sol.

[0147] 3. Preparation of silica sol coatings:

[0148] Add 52g of propylene glycol methyl ether acetate and 1088g of ethanol to the entire silica sol solution in step 2, and mix well to obtain a stable porous silica sol coating.

[0149] This comparative example also provides a type of glass, such as... Figure 2 As shown, the glass includes a glass substrate 1 and a coating 2, with the coating 2 covering the surface of the glass substrate 1. The coating 2 is a porous coating made of silica sol, prepared from the silica sol coating of this comparative example. Figure 3 As shown, coating 2 has a porous structure, and the pore size of the pores in coating 2 is 80-100 nm.

[0150] The glass preparation method of this comparative example includes the following steps:

[0151] The original glass sheet (as the glass substrate) is cleaned and dried. A conventional spraying process is used to coat the original glass sheet with silica sol coating. After the coating on the surface of the glass substrate dries, the glass substrate is cured at 150°C for 10 minutes and then tempered at 750°C for 5 minutes (during which the coating forms a silica sol coating with a porous structure). After cooling, the glass is obtained. This glass can be used as a porous silica sol coated automotive glass.

[0152] Comparative Example 2

[0153] This comparative example provides a silica sol coating, the preparation method of which includes:

[0154] 1. Emulsion preparation:

[0155] Using a three-necked flask equipped with a thermometer and a stirrer, add 0.2 g of emulsifier cetyltrimethylammonium bromide, 0.2 g of initiator azobisisopropylimidazoline hydrochloride, and 59.1 g of pure water. Start stirring, then add 40.0 g of styrene and 0.5 g of methacryloyloxyethyltrimethylammonium chloride to the flask. Stir until homogeneous and heat to 85°C. After reacting for 3 hours, cool to 50°C to obtain an emulsion.

[0156] The emulsion contains cationic polystyrene with a particle size of 200 nm.

[0157] Compared to the emulsion preparation method in Example 1, the amount of styrene monomer used in this comparative example is larger. In the free radical polymerization reaction, the molecular weight and particle size of the polymer macromolecule will gradually increase with the increase of monomer amount.

[0158] 2. Preparation of silica sol:

[0159] Add 150g tetraethyl orthosilicate, 30g KH560, and 314g ethanol to the entire emulsion from step 1, and start stirring. Dissolve 0.25g nitric acid in 6g water to obtain a catalyst solution, and add the catalyst solution to a three-necked flask. Heat to 50°C, maintain the temperature for 6 hours, then cool to room temperature. The resulting product is silica sol.

[0160] 3. Preparation of silica sol coatings:

[0161] Add 52g of propylene glycol methyl ether acetate and 1088g of ethanol to the entire silica sol solution in step 2, and mix well to obtain a stable porous silica sol coating.

[0162] This comparative example also provides a type of glass, such as... Figure 2 As shown, the glass includes a glass substrate 1 and a coating 2, with the coating 2 covering the surface of the glass substrate 1. The coating 2 is a porous coating made of silica sol, prepared using the silica sol coating of this embodiment. Figure 3 As shown, coating 2 has a porous structure, and the pore size of the pores in coating 2 is 180-220 nm.

[0163] The glass preparation method of this comparative example includes the following steps:

[0164] The original glass sheet (as the glass substrate) is cleaned and dried. A conventional spraying process is used to coat the original glass sheet with silica sol coating. After the coating on the surface of the glass substrate dries, the glass substrate is cured at 150°C for 10 minutes and then tempered at 750°C for 5 minutes (during which the coating forms a silica sol coating with a porous structure). After cooling, the glass is obtained. This glass can be used as a porous silica sol coated automotive glass.

[0165] Comparative Example 3

[0166] This embodiment provides a silica sol coating, the preparation method of which includes the following steps:

[0167] 1. Preparation of emulsion:

[0168] Using a three-necked flask equipped with a thermometer and a stirrer, add 0.2 g of emulsifier cetyltrimethylammonium bromide, 0.2 g of initiator azobisisopropylimidazoline hydrochloride, and 79.1 g of pure water. Start the stirrer, then add 20.0 g of styrene and 0.5 g of methacryloyloxyethyltrimethylammonium chloride to the flask. Stir until homogeneous and heat to 85°C. After reacting for 3 hours, cool to 50°C to obtain an emulsion.

[0169] The emulsion contains cationic polystyrene microspheres with a particle size of approximately 50 nm.

[0170] 2. Preparation of silica sol:

[0171] Using a three-necked flask equipped with a thermometer and a stirrer, add 150g of tetraethyl orthosilicate, 30g of KH560, and 314g of ethanol, and start stirring. Dissolve 0.25g of nitric acid in 6g of water to obtain a catalyst solution, and add the catalyst solution to the three-necked flask. Heat to 50°C, maintain this temperature for 6 hours, then cool to room temperature. The discharged product is silica sol.

[0172] 3. Preparation of silica sol coatings:

[0173] Mix all the emulsion from step 1 and all the silica sol solution from step 2, add 52g of propylene glycol methyl ether acetate and 1088g of ethanol, and mix thoroughly to obtain a stable silica sol coating.

[0174] Compared to Example 1, this comparative example did not add emulsion during the preparation of silica sol, but instead mixed the emulsion with the prepared silica sol for the preparation of coatings.

[0175] This comparative example also provides a type of glass, such as... Figure 2 As shown, the glass includes a glass substrate 1 and a coating 2, with the coating 2 covering the surface of the glass substrate 1. The coating 2 is a porous coating made of silica sol, prepared from the silica sol coating of this comparative example. Figure 3 As shown, coating 2 has a porous structure. The preparation method of the glass in this comparative example includes the following steps:

[0176] The original glass sheet (as the glass substrate) is cleaned and dried. A conventional spraying process is used to coat the original glass sheet with silica sol coating. After the coating on the surface of the glass substrate dries, the glass substrate is cured at 150°C for 10 minutes and then tempered at 750°C for 5 minutes (during which the coating forms a silica sol coating with a porous structure). After cooling, the glass is obtained. This glass can be used as a porous silica sol coated automotive glass.

[0177] Test Example 1

[0178] This test example provides test results for the appearance, coating thickness, visible light transmittance, haze, reflectance, hardness, abrasion resistance, and aging resistance of the glass with silica sol coating prepared in the above embodiments and comparative examples. The original glass sheet (i.e., glass substrate 1 in the above embodiments and comparative examples) is a 2mm thick ordinary clear glass with a visible light transmittance of 87.2%, haze of 0.29%, and reflectance of 7.93%. The test methods are as follows:

[0179] Coating thickness: The coating thickness was measured using a spectroelliptic spectrometer.

[0180] Visible light transmittance: The transmittance spectrum in the wavelength range of 250nm-2500nm was measured using a spectrophotometer. The visible light transmittance in the 380nm-780nm range was calculated according to ISO 9050 standard. The transmittance measured in this experiment is the average value obtained by measuring five different points on the same glass sample.

[0181] Reflectance: The reflectance of light in the wavelength range of 360nm-780nm is measured using a spectrophotometer to obtain the average reflectance.

[0182] Hardness: The hardness of the coating was tested according to the standard GB / T 6739-2006 "Determination of Hardness of Paint and Varnish Film by Pencil Method".

[0183] Abrasion resistance: Using a surface abrasion tester, the glass sample is placed on the instrument with the coating facing up, and a surface abrasion test is performed on it for 500 revolutions under a pressure of 4.9N.

[0184] Haze: A haze meter was used to test the glass samples before and after the abrasion resistance test. Haze H1 was obtained from the area that did not undergo the abrasion resistance test, and haze H2 was obtained from the area that did undergo the abrasion resistance test. The difference in haze before and after the test was calculated as H2 - H1. A haze difference of less than 2% before and after the test was considered acceptable for the coating's abrasion resistance.

[0185] Aging resistance: The aging resistance test method is to put the sample into a xenon lamp aging chamber, with a rainfall cycle of 102 minutes of drying followed by 18 minutes of rainfall, and a concentration of 300-400nm: 60±2w / m. 2 To determine the radiation intensity, the test duration is 3000 hours, the blackboard temperature is 65±3℃, and the relative humidity is 50±10% for the aging resistance test. After the aging resistance test, the appearance of the coating is observed to see if cracks appear. If no cracks appear, it is considered qualified; otherwise, it is considered unqualified.

[0186] Table 1

[0187]

[0188] It is understandable that the coating thicknesses prepared in the above embodiments and comparative examples are similar but not exactly the same. This degree of difference in coating thickness is an unavoidable error in the preparation process and will not have a significant impact on the optical and mechanical performance test results. The differences in the performance results of the above experiments mainly come from the differences in preparation parameters.

[0189] As can be seen from the test results in Table 1, the glass prepared in Examples 1, 2, 3, 4, 5 and 6 has a normal coating appearance after high-temperature curing, high visible light transmittance, low haze, low reflectivity and high hardness, and good wear resistance and aging resistance.

[0190] The mechanical properties of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were compared: the hardness of the glass prepared in Comparative Example 1 was 3H, and its wear resistance was unqualified; the hardness of the glass in Comparative Example 2 was 2H, and both its wear resistance and aging resistance were unqualified; the hardness of the glass in Comparative Example 3 was 2H; while the hardness of the glass in Example 1 was 4H, and its wear resistance and aging resistance were qualified.

[0191] The reason for the poor glass properties of Comparative Example 1 and Comparative Example 2 is that no cationic monomer was added to the raw materials of the emulsion during the preparation of the coating of Comparative Example 1, resulting in the emulsion having a neutral charge (polystyrene is neutral and uncharged). When mixed with other raw materials of silica sol, the compatibility is poor, resulting in uneven particle size distribution of silica sol in the coating and uneven porosity in the cured coating, which affects the wear resistance and hardness of the coating.

[0192] In the preparation process of the coating in Comparative Example 2, the amount of styrene added to the raw materials of the emulsion was large, resulting in a large particle size of the total polymer product of the emulsion; the pores of the silica sol network in the coating and the silica sol prepared by reacting the emulsion with alkoxysilane were too large, affecting the hardness, wear resistance and aging resistance of the coating.

[0193] In the preparation of the coating in Comparative Example 3, both the emulsion and silica sol were prepared separately and then mixed to form the coating. In the coating prepared solely by mixing and stirring, the cationic polystyrene enters the silica sol molecular network, resulting in uneven distribution and uneven pore distribution in the coating, thus affecting its hardness.

[0194] In contrast, Example 1, by adding cationic monomers and controlling the amount of styrene monomer added, resulted in a positively charged polymer (i.e., polystyrene) in the emulsion, with a moderate and uniform particle size. Using this emulsion to prepare silica sol, the positively charged polymers in the emulsion can combine with negatively charged alkoxysilanes through electrostatic attraction, exhibiting good compatibility. The resulting silica sol and coating have uniform particle size, and the coating formed has uniform pore size, exhibiting good hardness, wear resistance, and aging resistance.

[0195] Comparing the optical properties of the glasses in Comparative Examples 1, 2, 3, and 1, it can be seen that the glass in Example 1 has higher transmittance than the glasses in Comparative Examples 1, 2, and 3, and lower reflectance and haze than the glasses in Comparative Examples 1, 2, and 3, exhibiting better optical performance. This is because the porous coating of the glass in Example 1 has small and uniform pore sizes, which effectively reduces reflectance and increases light transmittance; while the porous structure of the coatings in the glasses in Comparative Examples 1 and 3 is unevenly distributed, and the pore size of the coating in the glass in Comparative Example 2 is too large, resulting in a less significant effect of reducing reflectance and increasing light transmittance.

[0196] The above results demonstrate that the silica sol coating provided by this invention has a short reaction time, a simple preparation process, and requires no complex formulation, enabling continuous production. The reaction raw materials do not require expensive substances or excessive amounts of multifunctional additives, resulting in low cost. Automotive glass with a porous coating prepared from this silica sol coating exhibits high light transmittance, excellent wear resistance and weather resistance, and a high cost-performance ratio.

Claims

1. A silica sol, the raw materials of which comprise an emulsion, an alkoxysilane, a silane coupling agent, a first organic solvent, a catalyst, and water in a mass ratio of 10-20:25-40:1-6:40-60:0.01-0.1:1-4; in, The raw materials of the emulsion include water, emulsifier, initiator, styrene and cationic monomer in a mass ratio of 70-90:0.1-0.25:0.1-0.25:10-30:0.1-1.

2. The silica sol according to claim 1, wherein, The emulsifier includes one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, dodecyl ammonium chloride, hexadecyltrimethylammonium bromide, and hexadecylpyridine bromide; And / or, the initiator includes one or more of the following: ammonium persulfate, potassium persulfate, sodium persulfate, azobisisopropylimidazoline hydrochloride, azobisisobutyramidine hydrochloride, and azobiscyanopentanoic acid; And / or, the cationic monomer includes a quaternary ammonium chloride.

3. The silica sol according to claim 2, wherein, The cationic monomer includes one or more of the following: methacryloyloxyethyltrimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, methacrylamidopropyltrimethylammonium chloride, acrylamidopropyltrimethylammonium chloride, and dimethyldiallylammonium chloride.

4. The silica sol according to claim 1, wherein, The structural formula of the alkoxysilane is: R 2 4-n Si(OR 1 ) n n is 1, 2, 3 or 4, R 1 Selected from alkyl groups, R 2 It is a non-hydrolyzable organic functional group; And / or, the silane coupling agent comprises γ-glycidoxypropyltrimethoxysilane and / or γ-methacryloyloxypropyltrimethoxysilane; And / or, the catalyst comprises hydrochloric acid and / or nitric acid.

5. The silica sol according to claim 4, wherein, R 2 It can be an alkyl or phenyl group.

6. The silica sol according to claim 4, wherein, The alkoxysilanes include one or more combinations of tetramethyl orthosilicate, tetraethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane.

7. A method for preparing silica sol according to any one of claims 1-6, the method comprising: S1. The raw materials for forming an emulsion are mixed with water, emulsifier, initiator, styrene monomer, and cationic monomer, and the raw materials of the emulsion undergo a polymerization reaction to obtain an emulsion; S2. Mix the emulsion, alkoxysilane, silane coupling agent, first organic solvent, catalyst and water, and react to obtain silica sol.

8. The preparation method according to claim 7, wherein, The polymerization reaction is carried out at a temperature of 75℃-85℃ for 3-5 hours.

9. The preparation method according to claim 7, wherein, In S2, the reaction temperature is 50℃-70℃, and the reaction time is 4h-6h.

10. A silica sol coating, comprising the silica sol according to any one of claims 1-6, an additive, and a second organic solvent; wherein, The mass ratio of the silica sol, additives, and second organic solvent is 25-35:2-5:60-70.

11. The silica sol coating according to claim 10, wherein, The adjuvants include propylene glycol methyl ether acetate and / or diethylene glycol ethyl ether.

12. A porous coating, wherein the porous coating is obtained by drying the silica sol coating of claim 10 or 11 and then subjecting it to a curing treatment and a tempering treatment in sequence.

13. The porous coating according to claim 12, wherein, The pore size in the porous coating is 40nm-80nm.

14. The porous coating according to claim 12, wherein, The curing temperature is 150℃-250℃, and the curing time is 5min-10min.

15. The porous coating according to claim 12, wherein, The tempering temperature is 650℃-750℃, and the tempering time is 5min-10min.

16. A glass comprising a glass substrate and a coating disposed on the surface of the glass substrate, said coating comprising the porous coating of any one of claims 12-15.

17. The glass according to claim 16, wherein, The thickness of the coating is 100nm-500nm.

18. The glass according to claim 16, wherein, The glass is further provided with a transparent conductive layer and / or a heat insulation layer, wherein the transparent conductive layer is disposed between the coating and the glass substrate, and the heat insulation layer is disposed between the coating and the glass substrate.

19. The glass according to claim 16, wherein, The glass has a transmittance of 89% or more for visible light in the 380nm-780nm range.

20. The glass according to claim 16, wherein, The haze of the glass is less than or equal to 0.3%.

21. The glass according to claim 16, wherein, The glass has a reflectivity of less than or equal to 5.6% for visible light in the 360nm-780nm range.

22. The glass according to claim 16, wherein, The difference in haze of the glass before and after the abrasion test is less than or equal to 1.5%.

23. A method for preparing the glass according to any one of claims 16-22, the method comprising: A silica sol coating is applied to the surface of a glass substrate. After the silica sol coating on the glass substrate surface dries, the glass substrate is cured and tempered to obtain the glass.

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