Nanometer core-shell particle, preparation method, anti-reflective coating solution and application thereof

Abstract

The application discloses a kind of nano core-shell particles and preparation method, anti-reflective coating solution and application, it is related to high polymer compound field, the nano core-shell particles in the anti-reflective coating solution includes core structure and shell structure, the core structure is anionic silicone acrylic emulsion as core template, using the silicon hydroxyl retained in anionic silicone acrylic emulsion particle hydration layer with the silicon hydroxyl produced by hydrolysis of precursor is condensed, with chemical bonding point as starting point, grows on the surface of particle, forms a layer of complete, uniform and interface firm silica shell layer.The ingenious solution anionic core cannot be combined with the problem of negative SiO2 precursor, and the anti-reflective coating formed is not easy to peel off, can reduce reflectivity, while maintaining good light transmittance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of thin films, in particular to a kind of nano core-shell particles and preparation method, anti-reflection coating fluid and application. BACKGROUND

[0002] Anti-reflection coating is applied to the surface of glass substrate, which can improve light transmittance and reduce surface reflection, and is widely used in the field of solar photovoltaic glass, display screen and optical instrument. Traditional production process takes cationic emulsion as core, needs specific cationic monomer or cationic emulsifier, and the production cost of raw material is higher. And production process is complex, cannot realize large-scale industrial production, therefore it is crucial to develop a kind of low-cost anti-reflection coating fluid which can improve light transmittance and reduce surface reflection.

[0003] Chinese invention patent CN102969366B discloses a kind of composite film material with optical anti-reflection and wavelength conversion function, in the silicon oxide SiOx matrix material evenly dispersed nano silicon crystal grain with particle size size less than 10nm, excess silicon-rich atom forms Si-O bond with surrounding oxygen atom, which helps to improve the optical performance of the material, but the preparation cost is higher. Chinese invention patent CN109912230B discloses a kind of double-layer infrared film glass with anti-reflection, self-cleaning and radiation cooling functions and its preparation method, which takes titanium dioxide coated silica core-shell structure as upper film, single-layer zinc oxide coating as lower film, and the two films are combined by spin coating deposition method. It has high transmittance in visible light band and high reflectivity in infrared band, and has anti-reflection, self-cleaning and radiation cooling functions, but the preparation process is complex and cannot realize large-scale industrialization. SUMMARY

[0004] In order to develop a kind of low-cost anti-reflection coating fluid which can improve light transmittance and reduce surface reflection, the first aspect of the present application provides a kind of nano core-shell particles, which comprises core structure and shell structure, the core structure takes anionic silicone acrylate emulsion as core template, and the anionic silicone acrylate emulsion is anionic silicone acrylate emulsion with silane content ≥5wt%.

[0005] As an embodiment, the mass ratio of the core structure and the shell structure is 1: (1-3).

[0006] As an embodiment, the thickness of the shell structure is 10-50nm.

[0007] As an embodiment, the thickness of the shell structure is 10-30nm.

[0008] As an embodiment, the thickness of the shell structure is 20nm.

[0009] In one embodiment, the raw materials for preparing the nano-core-shell particles include anionic silicone-acrylic emulsion, a catalyst, and a precursor.

[0010] In one embodiment, the catalyst is a solution containing an alkaline catalyst, wherein the alkaline catalyst is an inorganic weak base catalyst.

[0011] In one embodiment, the catalyst includes at least one of ammonia or tetramethylammonium hydroxide solution.

[0012] In one embodiment, the mass concentration of the catalyst is 25-30%.

[0013] In one embodiment, the precursor is a solution containing an alkoxysilane, wherein the alkoxysilane includes at least one of tetraethyl orthosilicate, methyl orthosilicate, methyltriethoxysilane, or methyltrimethoxysilane.

[0014] A second aspect of the present invention provides a method for preparing core-shell nanoparticles, comprising the following steps:

[0015] Prepare anionic silicone-acrylic emulsion;

[0016] The solid content of the anionic silicone-acrylic emulsion is diluted to 3-15% to obtain a suspension;

[0017] A catalyst and precursor are slowly added to the suspension to form a nano-core-shell particle emulsion;

[0018] The emulsion of the nano-core-shell particles was post-processed to obtain nano-core-shell particles.

[0019] As one embodiment, the method for preparing the nano-core-shell particles includes the following steps:

[0020] Prepare anionic silicone-acrylic emulsion;

[0021] With stirring, the solid content of the anionic silicone-acrylic emulsion was diluted to 3-15% with ethanol to obtain a suspension;

[0022] A catalyst and precursor are slowly added to the suspension to form a nano-core-shell emulsion;

[0023] The emulsion of the nano-core-shell particles was post-processed to obtain nano-core-shell particles.

[0024] In one embodiment, the diameter of the emulsion particles in the anionic silicone-acrylic emulsion is 50-250 nm.

[0025] In one embodiment, the diameter of the emulsion particles in the anionic silicone-acrylic emulsion is 50-150 nm.

[0026] In one embodiment, the pH of the nanocore-shell particle emulsion is 9.5-10.5.

[0027] In one embodiment, the emulsion particles of the anionic silicone-acrylic emulsion are at least one of polystyrene (PS), polymethyl methacrylate, or styrene-acrylate copolymer.

[0028] In one embodiment, the anionic silicone-acrylic emulsion is a commercially available emulsion or a self-made emulsion.

[0029] As one embodiment, the raw materials for preparing the self-made anionic silicone-acrylic emulsion include acrylic monomer, double-bonded silane, anionic emulsifier, initiator, and deionized water.

[0030] As one embodiment, the raw materials for preparing the self-made anionic silicone-acrylic emulsion include, by weight, 90-100 parts of acrylic acid monomer, 3-8 parts of double-bonded silane, 1-5 parts of anionic emulsifier, 0.5-0.9 parts of initiator, and 100 parts of deionized water.

[0031] As one embodiment, the raw materials for preparing the self-made anionic silicone-acrylic emulsion include, by weight, 95 parts acrylic monomer, 5 parts double-bonded silane, 3 parts anionic emulsifier, 0.6 parts initiator, and 100 parts deionized water.

[0032] As one embodiment, the preparation method of the self-made anionic silicone-acrylic emulsion includes the following steps: sodium dodecyl sulfate, ammonium persulfate and 100 mL of deionized water are mixed and heated to 75°C under nitrogen protection. Then, acrylic monomer is added dropwise over a period of 3 hours. After 2 hours of dropwise addition, double-bonded silane is added, mixed evenly, and the addition continues. The mixture is kept warm for 3 hours, cooled to 45°C, and the pH is adjusted to 8.5 to obtain the anionic silicone-acrylic emulsion.

[0033] As one implementation method, the post-processing is high-temperature heat treatment, wherein the temperature of the high-temperature heat treatment is ≥400℃.

[0034] As one embodiment, the post-processing step of the nano-core-shell particle emulsion includes: heating the nano-core-shell particle emulsion to 400°C to remove the organic core, and then cooling it to room temperature to obtain nano-core-shell particles.

[0035] A third aspect of the present invention provides an antireflective coating solution, the antireflective coating solution comprising at least a solvent and the aforementioned nano-core-shell particles.

[0036] As one embodiment, the raw materials for preparing the antireflective coating solution also include a binder; the binder is a silicone resin or a siloxane prepolymer, and the solid content of the binder in the antireflective coating solution is 1-3 wt%.

[0037] In one embodiment, the adhesive has a solid content of 3 wt% in the antireflective coating solution.

[0038] In one embodiment, the solvent includes, but is not limited to, isopropanol.

[0039] In one embodiment, the solid content of the nano-core-shell particles in the antireflective coating solution is 1-5 wt%.

[0040] In one embodiment, the solid content of the nano-core-shell particles in the antireflective coating solution is 3 wt%.

[0041] As one embodiment, the preparation method of the antireflective coating solution includes the following steps: dispersing nano-core-shell particles in a solvent, and then adding a binder to obtain the antireflective coating solution.

[0042] As one embodiment, the post-processing steps of the nano-core-shell particle emulsion include: dispersing the nano-core-shell particle emulsion in a solvent, adjusting the solid content to 3%, adding a binder, and obtaining an anti-reflection coating solution.

[0043] The antireflective coating solution was applied to the photovoltaic glass substrate by dip coating, dried at 100°C for 10 minutes, and then placed in a muffle furnace and calcined at 500°C for 2 hours. During the calcination process, the internal polyacrylate core was completely thermally decomposed (burned off) to obtain the antireflective coating.

[0044] In one embodiment, the antireflective coating surface has a porous SiO2 structure.

[0045] In this application, anionic silicone-acrylic emulsion is used as a template. A catalyst is introduced, and the precursor is hydrolyzed to form silanol groups. These silanol groups then condense with the silanol groups exposed on the surface of anionic silicone-acrylic emulsion particles with a silane content of ≥5%, forming Si-O-Si bonds and ultimately forming a SiO2 shell.

[0046] A fourth aspect of the present invention provides an application of an antireflective coating liquid in the fabrication of optical component products.

[0047] As one implementation, the optical element products include, but are not limited to, solar panels, displays, and optical instruments.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The antireflective coating solution containing nano-core-shell particles described in this invention can use inexpensive and readily available anionic silicone-acrylic emulsion as a template, avoiding the use of expensive cationic emulsions, reducing the production cost of the antireflective coating solution, and facilitating large-scale industrial production.

[0050] (2) The antireflective coating liquid containing nano-core-shell particles described in this invention uses the silanols retained in the hydration layer of anionic silicone-acrylic emulsion particles to condense with the silanols generated by the hydrolysis of the precursor. The silicon dioxide shell is epitaxially grown on the particle surface starting from the chemical bonding point to form a complete, uniform, and firmly bonded silicon dioxide shell.

[0051] (3) The antireflective coating solution containing nano-core-shell particles described in this invention uses a solution containing an alkaline catalyst, which can improve the hydrolysis rate and accelerate the encapsulation efficiency of the shell structure on the core structure.

[0052] (4) The antireflective coating liquid containing nano-core-shell particles described in this invention has a core structure and shell structure of nano-core-shell particles with a mass ratio of 1:(1-3), which can maintain the shell structure at a suitable thickness and form good light transmittance and low reflectance.

[0053] (5) The antireflective coating solution containing nano core-shell particles described in this invention has a post-treatment temperature of ≥400℃. The internal polyacrylate core is completely thermally decomposed (burned off) to form a porous SiO2 structure, which can reduce reflectivity while maintaining good light transmittance. Detailed Implementation

[0054] Example 1

[0055] A type of core-shell nanoparticle, comprising a core structure and a shell structure, wherein the core structure uses an anionic silicone-acrylic emulsion as a core template, and the anionic silicone-acrylic emulsion is an anionic silicone-acrylic emulsion with a silane content ≥5wt%.

[0056] The mass ratio of the core structure to the shell structure is 1:1.

[0057] The shell structure has a thickness of 20 nm.

[0058] A method for preparing core-shell nanoparticles includes the following steps:

[0059] Prepare commercially available anionic silicone-acrylic emulsion D009. Under vigorous stirring, dilute the solid content of the anionic silicone-acrylic emulsion to 10% with ethanol to obtain a suspension.

[0060] The catalyst and precursor were slowly added dropwise to 100 mL of the suspension, and the reaction was carried out at room temperature for 6 h to form a nano-core-shell particle emulsion.

[0061] The emulsion of the nano-core-shell particles was post-processed to obtain nano-core-shell particles.

[0062] The anionic silicone-acrylic emulsion has a solid content of 46%, a particle size of 80 nm, and was purchased from Shanghai Qixiang Qingchen New Material Technology Co., Ltd., with the grade name D009 and a silane content of 5.5 wt%.

[0063] The catalyst contains 45 mL of ethanol and 5 mL of concentrated ammonia (28 wt%).

[0064] The precursor contains 112 mL of ethanol and 38 mL of tetraethyl orthosilicate.

[0065] The post-processing steps include: centrifuging the nano-core-shell particle emulsion (8000 rpm, 15 min) to separate the particles and removing the supernatant. The particles are then washed twice with an ethanol-water solution (50 vol%), followed by centrifugation to obtain the nano-core-shell particles.

[0066] An antireflective coating solution is prepared by dispersing nano-core-shell particles in isopropanol, adding a binder, and adjusting the solid content to 3% to obtain the antireflective coating solution.

[0067] The antireflective coating solution was applied to the photovoltaic glass substrate by dip coating, dried at 100°C for 10 minutes, and then placed in a muffle furnace and calcined at 500°C for 2 hours to obtain the antireflective coating.

[0068] The antireflective coating has a porous SiO2 structure and exhibits excellent antireflective properties.

[0069] Example 2

[0070] A nano-core-shell particle and its preparation method, an anti-reflection coating solution and its application, the specific implementation method is the same as in Example 1, the difference being that the precursor includes 74 mL of ethanol and 76 mL of tetraethyl orthosilicate.

[0071] Increased mechanical hardness of antireflective coating (pencil hardness 4H).

[0072] Example 3

[0073] A nano-core-shell particle and its preparation method, an anti-reflection coating solution and its application, the specific implementation method is the same as in Example 1, the difference is that the anionic silicone-acrylic emulsion is purchased from Foshan Shunde Badefu Industrial Co., Ltd., the brand name is FS-798, and its silane content is 6.0wt%.

[0074] Example 4

[0075] A nano-core-shell particle and its preparation method, an anti-reflection coating solution and its application, the specific implementation method is the same as in Example 1, the difference is that the anionic silicone-acrylic emulsion is a self-made anionic silicone-acrylic emulsion, wherein the silane content of the self-made anionic silicone-acrylic emulsion is 5.0 wt%.

[0076] The raw materials for preparing the self-made anionic silicone-acrylic emulsion include 95g of acrylic monomer, 5g of double-bonded silane, 3g of anionic emulsifier, 0.6g of initiator, and 100mL of deionized water.

[0077] The acrylic monomer is a mixture of butyl acrylate and methyl methacrylate in a mass ratio of 2:1;

[0078] The double-bonded silane is γ-methacryloyloxypropyltrimethoxysilane;

[0079] The anionic emulsifier is sodium dodecyl sulfate;

[0080] The initiator is ammonium persulfate.

[0081] The method for preparing the self-made anionic silicone-acrylic emulsion includes the following steps: sodium dodecyl sulfate, ammonium persulfate and deionized water are mixed and heated to 75°C under nitrogen protection. Then, acrylic monomer is added dropwise over a period of 3 hours. After 2 hours of dropwise addition, double-bonded silane is added, mixed evenly, and the addition continues. The mixture is kept at this temperature for 3 hours, then cooled to 45°C. The pH is adjusted to 8.5 with ammonia water to obtain the anionic silicone-acrylic emulsion.

[0082] Comparative Example 1

[0083] A nano-core-shell particle and its preparation method, an anti-reflective coating solution and its application, the specific implementation method is the same as in Example 1, the difference is that the anionic silicone acrylic emulsion is replaced with a traditional cationic emulsion, which is purchased from Covestro cationic acrylic emulsion, brand name XK-351.

[0084] Comparative Example 2

[0085] A nano-core-shell particle and its preparation method, an anti-reflection coating solution and its application, the specific implementation method is the same as in Example 1, the difference is that the anionic silicone-acrylic emulsion is replaced with a traditional anionic acrylic emulsion, purchased from Shanghai Qixiang Qingchen New Material Technology Co., Ltd., brand name D208.

[0086] Traditional anionic acrylic emulsions do not involve silanes in emulsion synthesis, meaning the silane content is 0%.

[0087] The shell layer cannot cover the coating properly, and the coating appears foggy.

[0088] Comparative Example 3

[0089] A nano-core-shell particle and its preparation method, an anti-reflective coating solution and its application, the specific implementation method is the same as in Example 1, the difference being that the catalyst includes 45 mL of ethanol and 5 mL of hydrochloric acid.

[0090] The uneven SiO2 shell of the nano-core-shell particles leads to a decrease in optical performance.

[0091] Comparative Example 4

[0092] A nano-core-shell particle and its preparation method, an anti-reflection coating solution and its application, the specific implementation method is the same as in Example 1, the difference is that

[0093] The antireflective coating solution was applied to the photovoltaic glass substrate by dip coating and dried at 100°C for 10 minutes to obtain the antireflective coating.

[0094] The resulting antireflective coating has low porosity and cannot form a porous structure.

[0095] Comparative Example 5

[0096] A nano-core-shell particle and its preparation method, an anti-reflective coating solution and its application, the specific implementation method is the same as in Example 4, the difference being that the catalyst includes 45 mL of ethanol and 5 mL of acetic acid.

[0097] The system has a slow hydrolysis rate.

[0098] Comparative Example 6

[0099] A nano-core-shell particle and its preparation method, an anti-reflective coating solution and its application, the implementation method is the same as in Example 4, the difference being that the mass ratio of the core structure to the shell structure is 1:4.

[0100] That is, the precursor contains 152 mL of tetraethyl orthosilicate.

[0101] The shell structure of the nano-core-shell particles is too thick, resulting in high mechanical strength but slightly reduced optical performance.

[0102] Performance testing

[0103] The double-sided transmittance of the uncoated glass substrate is 91.5%.

[0104] 1. Transmittance: The transmittance of the glass with antireflective coating in the examples and comparative examples with Shimadzu UV2600 was tested in the wavelength range of 380nm-1100nm, and the average value was taken.

[0105] 2. Pencil Hardness: Using a set of standard graphite pencils ranging from soft (e.g., 6B) to hard (e.g., 9H), the pencils were rubbed at a 45° angle and with a constant load of 750 grams onto the glass surfaces containing anti-reflective coatings in the examples and comparative examples. The “pencil hardness” value of the coating was determined by observing whether the pencils could scratch the coating.

[0106] The performance test results are shown in Table 1 below.

[0107] Table 1

[0108]

Claims

1. A type of core-shell nanoparticle, characterized in that, The nano-core-shell particles include a core structure and a shell structure, wherein the core structure uses an anionic silicone-acrylic emulsion as the core template and the shell structure is a silica shell layer. The anionic silicone-acrylic emulsion is an anionic silicone-acrylic emulsion with a silane content ≥ 5 wt%; The mass ratio of the core structure to the shell structure is 1:(1-3); The raw materials for preparing the nano-core-shell particles include anionic silicone-acrylic emulsion, catalyst, and precursor; The catalyst is a solution containing an alkaline catalyst, which is an inorganic weak base catalyst.

2. The nano-core-shell particles according to claim 1, characterized in that, The precursor is a solution containing an alkoxysilane, wherein the alkoxysilane includes at least one of tetraethyl orthosilicate, methyl orthosilicate, methyltriethoxysilane, or methyltrimethoxysilane.

3. A method for preparing nano-core-shell particles according to any one of claims 1-2, characterized in that, Includes the following steps: Prepare anionic silicone-acrylic emulsion; The solid content of the anionic silicone-acrylic emulsion is diluted to 3-15% to obtain a suspension; A catalyst and precursor are slowly added to the suspension to form a nano-core-shell particle emulsion; The emulsion of the nano-core-shell particles was post-processed to obtain nano-core-shell particles.

4. The preparation method according to claim 3, characterized in that, The diameter of the emulsion particles in the anionic silicone-acrylic emulsion is 50-250 nm.

5. An antireflective coating solution, characterized in that, The antireflective coating solution includes at least a solvent and the nano-core-shell particles as described in any one of claims 1-2, wherein the solid content of the nano-core-shell particles in the antireflective coating solution is 1-5 wt%.

6. An application of the antireflective coating solution according to claim 5, characterized in that, It is used in the fabrication of optical components.

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