CN114933820A - High-weather-resistance coating film and preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of solar photovoltaic technology, and provides a coating film with high weather resistance and a preparation method and application thereof. Small diameter, and further applied to the preparation of coated glass, it can be made into coated glass with high light transmittance, high hardness and good weather resistance, the hardness is not less than 5H, the light transmittance is not less than 94.56%, and the antireflection is not less than 94.56%. Less than 2.56%, and in the weather resistance test such as salt spray resistance test, constant temperature and humidity test, outdoor exposure test, ultraviolet test, friction test, acid resistance test, wet freezing test, etc., the change of light transmittance does not exceed 0.15%, it can be Applied in the field of solar photovoltaic.

Description

A kind of high weather-resistant coating and its preparation method and application

technical field

The present invention relates to the technical field of photovoltaic glass, and more particularly, to a coating film with high weather resistance and a preparation method and application thereof.

Background technique

The optical properties of photovoltaic glass have a great influence on the conversion efficiency of solar cells. Therefore, efforts are being made to improve the transmittance of photovoltaic glass. The latest method is to coat photovoltaic glass with a double-layer anti-reflection film, that is, double-layer anti-reflection film. , The double-layer anti-reflection film can make a certain wavelength band have a very low reflectivity, thus broadening the bandwidth area, which can greatly improve the average transmittance in the full spectrum (380-1100nm) range, thereby improving the output power of solar photovoltaic modules. According to the principle of double-layer anti-reflection coating (AR film), a layer of high-refractive-index silicon dioxide is firstly coated on the surface of photovoltaic glass as the bottom layer. A layer of low refractive index top layer is coated on the high refractive index bottom layer. According to the requirements of thin film optics, the refractive index of the single-layer coating is about 1.27-1.35, and the refractive index of the top layer should be reduced to 1.15-1.25, that is, it is necessary to increase the double-layer film. top layer porosity. At present, the core-shell structure silica-alumina sol prepared by the template method is usually used as the raw material for the top layer of the double-layer film. The template method is simple in principle and mature in the preparation process. Macromolecular organic matter is used as the spherical template. It is evenly coated on the outer surface of the template, and finally the template in the center is removed to obtain silica-alumina sol nanoparticles with a core-shell structure. It is difficult to control the particle size of silica-alumina sol at the nanometer scale, so if the refractive index is to be low, the film layer needs to be thin enough, and the film layer is too thin, resulting in a low structural strength of the film layer, and it is difficult to resist the impact of the external environment, resulting in the film layer being too thin. The layer is easily damaged by water vapor, thus affecting the weather resistance of the product. Therefore, there is an urgent need to develop a coating with good weather resistance.

SUMMARY OF THE INVENTION

The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a highly weather-resistant coating and its preparation method and application. The coating provided by the present invention can be further used to prepare coated glass, so that the coated glass has the characteristics of high weather resistance, high hardness and high light transmittance. Not less than 5H, the transmittance is not less than 94.56%, the antireflection is not less than 2.56%, and in the weather resistance test, the change of the transmittance is not more than 0.15%.

A first aspect of the present invention provides a coating with high weather resistance.

Specifically, a coating with high weather resistance includes a two-layer structure: a first coating and a second coating;

The raw materials for preparing the first coating film include a first coating solution, and the first coating solution includes a silica-alumina sol with a core-shell structure, the core is an oil-in-water microemulsion, and the shell is aluminum-doped silica ;

The raw materials for preparing the second coating film include a second coating solution; the second coating solution includes a cationic silica sol, an epoxy silane oligomer and a silane coupling agent.

The present invention adopts a silica-alumina sol with a core-shell structure to prepare a first coating solution, wherein the core is an oil-in-water microemulsion, the shell is aluminum-doped silica, and the silica-alumina sol does not contain organic matter with a large particle size as a spherical template ( core), so the particle size of the silica-alumina sol is small, and the silica-alumina sol of the core-shell structure uses aluminum-doped silica as the outer shell, and aluminum element is introduced into the outer shell, which can better improve the adhesion between the coating film and the substrate. The bonding force improves the hardness of the film layer. The first coating and the second coating cooperate to obtain a coating with a two-layer structure. By changing the size and arrangement of holes in the film, the structural strength of the system is enhanced, and the permeability of the coating is improved. It also improves the hardness and weather resistance of the coating.

Preferably, the oil-in-water microemulsion includes water, an oil phase solvent and an emulsifier.

Preferably, the average particle size of the silica-alumina sol of the core-shell structure is 50-75 nm.

More preferably, the average particle size of the silica-alumina sol of the core-shell structure is 55-60 nm.

Preferably, the solid content of the first coating solution is 3%-6%.

More preferably, the solid content of the first coating solution is 3.5%.

Preferably, the first coating solution further includes an organic solvent.

Preferably, the organic solvent is isopropanol.

Preferably, the second coating solution further comprises silica prepolymer, surfactant and propylene glycol butyl ether.

More preferably, in parts by weight, the second coating solution includes 25-35 parts of silica prepolymer, 15-25 parts of silane coupling agent, 15-20 parts of isopropanol, and 20-30 parts of cationic silica sol. parts, 1-2 parts of surfactant, 4-8 parts of propylene glycol butyl ether, and 1-10 parts of epoxy silane oligomer.

The second aspect of the present invention provides the application of a coating film with high weather resistance.

The invention protects the application of the above-mentioned highly weather-resistant coating film in the field of solar photovoltaic.

A third aspect of the present invention provides a coated glass.

The present invention protects a coated glass comprising the above-mentioned coating.

Preferably, the coated glass includes a first coating film, a second coating film, and a glass substrate in order from top to bottom.

A fourth aspect of the present invention provides a method for preparing coated glass.

The present invention protects the preparation method of the above-mentioned coated glass, comprising the following steps:

After the second coating solution is coated on the glass substrate, the glass substrate containing the second coating is prepared through the first curing; and then the first coating solution is applied on the second coating. Coating, second curing, and then tempering treatment to prepare the coated glass.

Preferably, the temperature of the first curing is 60-250° C., and the time of the first curing is 1-5 min.

Preferably, the temperature of the second curing is 80-250° C., and the time of the second curing is 1-5 min.

Preferably, the temperature of the tempering treatment is 500-700° C., and the time of the tempering treatment is 1-5 min.

Preferably, the first coating solution is prepared by mixing the above-mentioned core-shell structure silica-alumina sol with an organic solvent, and diluting to a solid content of 3%-6% to prepare the first coating solution.

Preferably, the preparation method of the silica-alumina sol of the core-shell structure comprises the following steps:

Mix water and emulsifier, then add oil phase solvent and mix to obtain oil-in-water microemulsion system, add alkoxysilane and aluminum salt, react at 25-70°C for 1-3h, after standing, The core-shell structure of silica-alumina sol was prepared.

Preferably, in terms of mass percentage, the raw materials for preparing the core-shell structure silica-alumina sol include:

Emulsifier 0.5%-1.5%;

Oil phase solvent 1.5%-3.5%;

Alkoxysilane 15%-30%;

Aluminum salt 0.02%-0.5%;

Water 65%-83%.

Preferably, the emulsifier is sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, potassium rosinate, sodium succinate sulfonate, dodecylammonium chloride, cetyltrimethyl One or more of ammonium bromide, cetylpyridinium bromide, Tritox-100, Span40, Span60, Span80, Tween40, Tween60, Tween80, and NP-5.

Preferably, the oil phase solvent is one or more of kerosene, n-octyl ammonia, n-hexadecane, trimethylbenzene, oleic acid, n-hexane, diesel oil, and cyclohexane.

Preferably, the alkoxysilane is tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, tetramethoxysilane, vinyltriethylsilane One or more of oxysilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-(2,3-glycidoxy)propyltrimethoxysilane.

Preferably, the aluminum salt is aluminum nitrate, aluminum chloride, aluminum phosphate, aluminum formate, aluminum acetate, aluminum propionate, dialkyl aluminum chloride, methyl aluminum dichloride, trialkyl aluminum trichloride , one or more of aluminum isopropoxide and aluminum acetylacetonate.

Preferably, the preparation method of the second coating solution includes the following steps:

Mix silica prepolymer, silane coupling agent, isopropanol, cationic silica sol, surfactant, propylene glycol butyl ether, and raise the temperature of the reaction system to 35-55°C, then cool to room temperature; then add epoxy Silane oligomers are mixed to obtain a mixture, and finally diluted with isopropanol until the solid content of the mixture is 2%-4% to prepare a second coating solution.

Preferably, the raw materials for preparing the silica prepolymer include ethyl silicate-40, isopropanol, glacial acetic acid and water.

Preferably, in parts by weight, the raw materials for preparing the silica prepolymer include:

40-60 parts of ethyl silicate-40, 45-60 parts of isopropanol, 0.1-1 part of glacial acetic acid, and 10-20 parts of water.

Preferably, the preparation method of the silica prepolymer comprises the steps:

Ethyl silicate-40, isopropanol, glacial acetic acid and water are mixed, hydrolyzed at 25-30 °C, then heated to 70-80 °C for 2-3 hours, and cooled to obtain silica prepolymer.

Preferably, the hydrolysis time is 30-50h.

Preferably, the cooling temperature is 25-30°C.

A fifth aspect of the present invention provides an application of coated glass.

The invention also protects the application of the above-mentioned coated glass in the field of solar photovoltaic.

A sixth aspect of the present invention provides a solar cell.

The present invention also protects a solar cell, which is prepared from the above-mentioned coated glass.

With respect to the prior art, the beneficial effects of the present invention are as follows:

(1) The highly weather-resistant coating provided by the present invention has a two-layer structure, which is a first coating and a second coating, and further utilizes the highly weather-resistant coating to prepare coated glass, and the structure of the coated glass sequentially includes the first coating, The second coating, glass substrate; the hardness of the coated glass provided by the present invention is not less than 5H, the light transmittance is not less than 94.56%, the antireflection is not less than 2.56%, and in the weather resistance test, its light transmittance changes not more than 0.15%; the coated glass of the present invention has the advantages of high hardness, high light transmittance and good weather resistance;

(2) the present invention adopts microemulsion method, utilizes oil phase solvent, water and emulsifier to form oil-in-water (O/W) microemulsion system, then monomer and aluminum salt are dispersed into microemulsion state by emulsifier in water, At the same time, the polymerization reaction occurs to generate microspheres, and the obtained core-shell structure silica-alumina sol has a small average particle size, the average particle size is about 60 nm, and the monodispersity and stability are good. The production cost of the method is low, the process is simple, and the The rapid realization of industrial production is more advantageous than the silica-alumina sol prepared by the template method.

Description of drawings

FIG. 1 is an electron microscope image of the silica-alumina sol with a core-shell structure prepared in Example 1. FIG.

Detailed ways

In order to make those skilled in the art understand the technical solutions of the present invention more clearly, the following examples are now given for illustration. It should be noted that the following examples do not limit the protection scope of the present invention.

The raw materials, reagents or devices used in the following examples can be obtained from conventional commercial channels unless otherwise specified, or can be obtained by existing known methods.

Example 1

A coating with high weather resistance, comprising a two-layer structure: a first coating and a second coating;

The raw material for preparing the first coating film includes a first coating solution, and the first coating solution includes a silica-alumina sol with a core-shell structure, the core is an oil-in-water microemulsion, and the shell is aluminum-doped silica;

The raw materials for preparing the second coating film include a second coating solution; the second coating solution includes cationic silica sol, epoxy silane oligomer, silane coupling agent, silica prepolymer, surfactant, and propylene glycol butyl ether.

A coated glass is prepared by including the above-mentioned coating; from top to bottom, it includes a first coating, a second coating and a glass substrate.

The preparation method of the above-mentioned coated glass comprises the following steps:

1. Preparation of core-shell silica-alumina sol by microemulsion method

(1) get 200mL deionized water and put it in a beaker, add 2g cetyl trimethyl ammonium bromide (CTAB) again to emulsify, put into warm water of 50 ℃ after sealing and carry out ultrasonic dissolving, to emulsifying completely;

(2) measure 5mL n-hexadecane as oil phase and add in the mixed solution in (1) with syringe, carry out magnetic stirrer so that the two can be mixed evenly, and form O/W microemulsion system;

(3) Measure 20 mL of ethyl orthosilicate with a syringe and weigh 0.05 g of aluminum isopropoxide, add it to the O/W microemulsion system of (2), and perform a water bath and ultrasonic agitation on the mixture at 50°C. Control at 600rpm, stirring time is 75 minutes;

(4) the solution in the beaker is allowed to stand at room temperature for 24 hours to obtain a core-shell structure silica-alumina sol with an average diameter of about 60 nm, with good monodispersity and stability;

The particle diameter of the present invention is all measured by the model ZetaZS90 laser particle size analyzer of Malvern company;

2. Preparation of the first coating solution

adding the above-mentioned core-shell structure silica-alumina sol into isopropanol to dilute to a solid content of 3.5% to prepare a first coating solution;

3. Preparation of the second coating solution

(1) Mix 50g of ethyl silicate-40, 55g of isopropanol, 0.5g of glacial acetic acid and 15g of water, hydrolyze at room temperature for 40h, then heat up to 75°C for 2.5h, cool down to room temperature, and obtain the carbon dioxide Silicon prepolymer;

(2) 25g silica prepolymer, 15g methyltrimethoxysilane, 18g isopropanol, 25g LevasilCT16PCL cationic silica sol, 1.5g cetyltrimethylammonium bromide, 6g propylene glycol butyl ether Mix evenly, the reaction process exothermic, and the reaction system is heated to 45 ° C, and then placed for 1.8 hours to cool to room temperature naturally; then add 5 g of Momentive CoatOSilMP200, mix evenly to obtain a mixture, and finally dilute it with isopropanol to the concentration of the mixture. The solid content is 3%, and the second coating solution is prepared;

4. Preparation of Coated Glass

(1) After the first coating solution is coated on the ultra-white solar glass (3.2mm thick patterned glass) with a light transmittance of 92.00% in the first coating room, it enters the curing furnace to cure, the curing temperature is 250°C, and the curing time is 5min , that is, the glass containing the first coating is obtained;

(2) Roll coating the second coating solution on the glass containing the first coating between the second coating films, then bake and cure at 180°C for 3 minutes, then enter the tempering furnace, and undergo tempering treatment at 700°C for 2 minutes to obtain coated glass.

Comparative Example 1

A coated glass is different from Example 1 in that the core-shell structure silica-alumina sol is replaced by a silica-coated polystyrene core-shell structure microsphere emulsion prepared by a template method.

The preparation method of the above-mentioned coated glass comprises the following steps:

1. Preparation of the first coating solution

(1) Utilize soap-free emulsion polymerization to prepare polystyrene emulsion: take comonomer acryloyloxyethyltrimethoxyammonium chloride and 100mL of water and place it in a 250mL four-necked flask, add styrene under mechanical stirring, and stir 30min at a stirring speed of 150rpm; under nitrogen protection, the temperature was raised to 50°C, and an aqueous solution of the initiator potassium persulfate (KPS) was added dropwise. The cationic polystyrene emulsion, the mass content of solid content is 10%; the mass percentages of comonomer, styrene monomer, initiator and water in the whole system are 0.5% of comonomer and 10% of styrene, respectively. Initiator 0.1%, water 89.4%;

(2) Mix the above-mentioned cationic polystyrene emulsion and methanol solvent evenly, dilute the cationic polystyrene emulsion to a solid content of 5%, and then slowly drop the silicon source material tetramethoxysilane under stirring at 15°C. It was added to make the mass ratio of silicon source material: polystyrene emulsion to be 9:1, and the reaction was carried out for 3 hours to obtain a core-shell structure microsphere emulsion of silica-coated polystyrene; after measurement, heating and drying at 150 °C 2 hours, the residual solids content is about 16%;

(3) diluting the core-shell structure microsphere emulsion of the above-mentioned silica-coated polystyrene with isopropanol to a solid content of 4% to obtain the first coating solution;

2. Preparation of the second coating solution

(1) Mix 50g of ethyl silicate-40, 55g of isopropanol, 0.5g of glacial acetic acid and 15g of water, hydrolyze at room temperature for 40h, then heat up to 75°C for 2.5h, cool down to room temperature, and obtain the carbon dioxide Silicon prepolymer;

(2) 25g silica prepolymer, 15g methyltrimethoxysilane, 18g isopropanol, 25g LevasilCT16PCL cationic silica sol, 1.5g cetyltrimethylammonium bromide, 6g propylene glycol butyl ether Mix evenly, the reaction process exothermic, and the reaction system is heated to 45 ° C, and then placed for 1.8 hours to cool to room temperature naturally; then add 5 g of Momentive CoatOSilMP200, mix evenly to obtain a mixture, and finally dilute it with isopropanol to the concentration of the mixture. The solid content is 3%, and the second coating solution is prepared;

3. Preparation of Coated Glass

(1) After coating the second coating solution on the ultra-white solar glass (3.2mm thick patterned glass) with a light transmittance of 92.00% between the first coating films, enter the curing oven to cure, the curing temperature is 250°C, and the curing time is 5min , that is, the glass containing the second coating is obtained;

(2) Roll coating the first coating solution on the glass containing the second coating between the second coating films, then bake and solidify at 180°C for 3 minutes, and then enter the tempering furnace, and undergo a tempering treatment at 700°C for 2 minutes , the coated glass was obtained.

Product effect test

1. Test method

(1) Light transmittance: refers to the average light transmittance TE measured in the range of 380nm to _1100nm . The calculation formula is as follows:

In the formula, Sλ: relative spectral distribution of AM1.5 sunlight; Δλ: wavelength interval, nm; τ(λ): measured sunlight spectral transmittance of the sample.

(2) Determination of mechanical strength - pencil hardness performance

The pencil hardness of the coating was measured with reference to the Chinese national standard GB/T6739, with a load of 750g.

(3) Weather resistance test

The following weather resistance tests were carried out on the coated glass, and then the change in light transmittance was determined. The standards and device models determined are summarized in Table 1 below:

Table 1 Device models corresponding to each test of coated glass

2. Test results

Table 2 Test results of the coated glass of Example 1

It can be seen from the above Table 2 that the coated glass prepared in Example 1 of the present invention has a hardness of 5H, and has been measured to have a light transmittance of 94.56% and an antireflection of 2.56%. It has the characteristics of high hardness and high antireflection, and is resistant to salt. In fog test, constant temperature and humidity test, outdoor exposure test, ultraviolet test, friction test, acid resistance test, wet freezing test and other weather resistance tests, the change of light transmittance does not exceed 0.15%, which has the advantage of high weather resistance.

Table 3 Test results of the coated glass of Comparative Example 1

From the test results in Table 3 above, it can be seen that the hardness of the coated glass film in Comparative Example 1 is only 3H, which also causes the film to be easily damaged by water vapor. The salt spray test fails the test. In the constant temperature and humidity test and friction test, the transmittance The change is also close to 1%, the light transmittance is 94.3%, and the antireflection performance is 2.3%. It can be seen that the hardness, weather resistance and antireflection performance of the coated glass of Comparative Example 1 all decrease. Description Comparative Example 1 The core-shell structure microsphere emulsion of silica-coated polystyrene prepared by the template method, due to its large particle size (the average particle size of the cationic polystyrene emulsion is 270 nm), the obtained The structural strength of the film layer of the first coating film is relatively low, and the outer shell does not contain aluminum element, the bonding force between the coating film layer and the substrate decreases, and the hardness decreases.

Figure 1 is an electron microscope image of the core-shell silica-alumina sol prepared in Example 1, wherein Figures 1a-b are SEM images of the core-shell silica-alumina sol under different magnifications, and Figures 1c-d are the core-shell structure of the silica-alumina sol. TEM images of silica-alumina sol at different magnifications. It can be seen from Figure 1a-b that the prepared silica-alumina sol has high sphericity, an average particle size of about 60 nm, and good particle uniformity without large particles, which greatly improves the colloidal stability. In addition, it can be seen from Figure 1c-d that the colloidal particles of the silica-alumina sol are all core-shell structures, with a shell thickness of about 10 nm and good dispersibility.

Claims (10)

1. A coating film, comprising a two-layer structure: a first plating film and a second plating film;

the raw material for preparing the first coating comprises a first coating solution, wherein the first coating solution comprises silicon-aluminum sol with a core-shell structure, the core is oil-in-water microemulsion, and the shell is aluminum-doped silicon dioxide;

the raw material for preparing the second coating comprises a second coating solution; the second coating solution comprises cationic silica sol, epoxy silane oligomer and silane coupling agent.

2. The plating film according to claim 1, wherein the oil-in-water microemulsion comprises water, an oil-phase solvent, and an emulsifier.

3. The coating film according to claim 1, wherein the silica-alumina sol of the core-shell structure has an average particle diameter of 50 to 75 nm.

4. Use of the coating film according to any one of claims 1 to 3 in the field of solar photovoltaics.

5. A coated glass comprising the coating film according to any one of claims 1 to 3.

6. The coated glass of claim 5, which comprises a first coating, a second coating and a glass substrate in sequence from top to bottom.

7. The method for preparing a coated glass according to claim 5 or 6, comprising the steps of:

after the second coating solution is coated on the glass substrate, the glass substrate containing a second coating is prepared through first curing; and then coating the first coating solution on the second coating, curing for the second time, and then tempering to obtain the coated glass.

8. The preparation method of claim 7, wherein the first coating solution is prepared by mixing the silica-alumina sol having the core-shell structure with an organic solvent, and diluting the mixture to a solid content of 3-6% to obtain the first coating solution.

9. Use of the coated glass according to claim 5 or 6 in the field of solar photovoltaics.

10. A solar cell comprising the coated glass of claim 5 or 6.

Images