Low temperature sintering white photovoltaic glass enamel and method for preparing the same

Abstract

The application discloses a low-temperature curing white glaze for photovoltaic glass and a preparation method thereof. The white glaze is prepared from an acrylic emulsion and a curing agent. The acrylic emulsion is prepared from raw materials including rutile titanium dioxide and cationic acrylic resin emulsion, and the curing agent is prepared from raw materials including silicon dioxide and siloxane resin. The rutile titanium dioxide with high refractive index is used as the main body to improve the reflectivity of the glaze. The cationic acrylic resin emulsion with high hydroxyl value and modified silicon dioxide are used. The hydroxyl groups of the siloxane can react with the hydroxyl groups in the acrylic resin and the hydroxyl groups on the surface of the glass. Meanwhile, the excess hydroxyl groups in the siloxane can condense with each other and fill the gaps in the powder accumulation, so that the compactness of the glaze is improved. The adhesion between the glaze and the glass after curing reaches 0 level. The average reflectivity of the glaze is as high as 86.83% in the wavelength range of 380-1200 nm. Meanwhile, the glaze does not have the phenomena of performance attenuation such as aging and yellowing under the irradiation of sunlight.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photovoltaic modules, and particularly relates to a low-temperature curing white glaze for photovoltaic glass and a preparation method thereof. BACKGROUND

[0002] A double-glass photovoltaic module is composed of a front plate glass, a back plate glass and solar cell pieces, etc. In the preparation process of the double-glass photovoltaic module, due to the fact that the solar cell pieces cannot be closely attached, a gap is generated in the middle. In the use process, sunlight is directly transmitted through the glass, causing waste of light source. In order to effectively improve the efficiency of the double-glass photovoltaic module, the common practice is to apply white glaze to the photovoltaic back plate glass by a silk printing process or a spraying process to form a high reflection coating, so as to reflect sunlight to the surface of the solar cell piece and improve the photoelectric power generation efficiency of the module. At present, domestic manufacturers achieve the purpose of reflecting sunlight by attaching a light-reflecting strip in the gap of the solar cell piece, but the preparation cost of the light-reflecting strip is high, the average reflectivity can only reach about 80%, and the adhesion with the glass is poor, which has certain risks in the later application. SUMMARY

[0003] In order to solve the technical problems existing in the prior art, the purpose of the present application is to provide a low-temperature curing white glaze for photovoltaic glass and a preparation method thereof.

[0004] In order to achieve the above-mentioned purposes and achieve the above-mentioned technical effects, the technical scheme adopted by the present application is as follows:

[0005] A low-temperature curing white glaze for photovoltaic glass is prepared by using an acrylic emulsion and a curing agent. The preparation raw materials of the acrylic emulsion include rutile titanium dioxide and cationic acrylic resin emulsion, and the preparation raw materials of the curing agent include silicon dioxide and siloxane resin.

[0006] Further, the preparation raw materials of the acrylic emulsion include the following components in the following weight fractions:

[0007] Rutile titanium dioxide 50-100 parts

[0008] Cationic acrylic resin emulsion 40-60 parts

[0009] Kaolin powder 5-15 parts

[0010] Deionized water 30-50 parts

[0011] Defoaming agent 1-2 parts

[0012] Dispersing agent 1-2 parts

[0013] Thickening agent 1-2 parts

[0014] Wetting and leveling agent 0.5-1 part.

[0015] Further, the cationic acrylic resin emulsion has a hydroxyl value of 1.5-2 mgKOH / g and a minimum film formation temperature of 15-25℃.

[0016] Further, the raw materials for preparing the curing agent include the following components by weight:

[0017] 30-40 parts of basic silica sol

[0018] 30-40 parts of siloxane resin

[0019] 30-40 parts of deionized water

[0020] 0.25-1 part of acetic acid.

[0021] Further, the siloxane resin is a mixture of methyl triethoxysilane and γ-(2,3-epoxypropoxy) propyl trimethoxysilane, and the mass ratio of the methyl triethoxysilane to the γ-(2,3-epoxypropoxy) propyl trimethoxysilane is 1:0-2.

[0022] Further, the particle size of the basic silica sol is 30-40 nm.

[0023] Further, the mass ratio of the acrylic emulsion to the curing agent is 10:4-10.

[0024] The application discloses a preparation method of a low-temperature curing white glaze for photovoltaic glass.

[0025] 1) Preparation of acrylic emulsion

[0026] Deionized water is weighed, part of the defoaming agent, all of the dispersing agent are sequentially added, and then the rutile titanium dioxide and kaolin powder are added and stirred and dispersed into a paste, followed by adding the thickening agent, wetting and leveling agent and the remaining defoaming agent, and then the cationic acrylic resin emulsion is added, and the acrylic emulsion is obtained after uniform stirring.

[0027] 2) Preparation of curing agent

[0028] The basic silica sol is weighed and diluted with deionized water, and then the mixed solution composed of the siloxane resin and acetic acid is added under stirring, and the solution gradually reacts from turbid two phases into a uniform single phase after uniform stirring, and the solution changes from alkaline to acidic, and the curing agent is obtained.

[0029] 3) The acrylic emulsion obtained in step 1) and the curing agent obtained in step 2) are mixed according to a certain mass ratio, and the low-temperature curing white glaze for photovoltaic glass is obtained.

[0030] The application further discloses a high-reflection coating prepared by curing the low-temperature curing white glaze for photovoltaic glass for a certain time.

[0031] Further, the low-temperature curing for a certain time is curing at 70-80 DEG C for 10-15 min or curing at room temperature of 20-25 DEG C for 6-12 h.

[0032] Compared with the prior art, the application has the following beneficial effects:

[0033] The application discloses a low-temperature curing white glaze for photovoltaic glass and a preparation method thereof. The white glaze is prepared from an acrylic emulsion and a curing agent. The preparation raw material of the acrylic emulsion comprises rutile titanium dioxide and cationic acrylic resin emulsion, and the preparation raw material of the curing agent comprises silicon dioxide and siloxane resin. The rutile titanium dioxide with a refractive index of 2.76 is used as the main body to improve the reflectivity of the glaze and the coating after curing. The cationic acrylic resin emulsion with high hydroxyl value is used as the binder, and the silicon dioxide modified by the siloxane resin is used as the curing agent. The hydroxyl groups in the siloxane can be dehydrated and condensed with the hydroxyl groups in the acrylic resin to generate Si-O-C bonds, and can be dehydrated and condensed with the hydroxyl groups on the surface of the glass to generate Si-O-Si bonds. Meanwhile, the excessive hydroxyl groups in the siloxane can be condensed with each other to generate Si-O-Si with large bond energy and fill the gaps in the titanium dioxide powder accumulation. After the glaze is cured, the adhesion between the coating and the glass is enhanced, and can reach 0 level. The average reflectivity of the coating in the wavelength range of 380-1200 nm is significantly improved, and can be as high as 86.83%. Meanwhile, the curing agent after curing is inorganic composition, and the cationic acrylic resin emulsion is pure acrylic emulsion, and no aging yellowing performance attenuation and other phenomena occur under the irradiation of sunlight. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a broad spectrum curve of the high-reflection coating of the embodiment 2 of the application. DETAILED DESCRIPTION

[0035] The application will be described in detail below so that the advantages and features of the application can be more easily understood by those skilled in the art, and the protection scope of the application can be more clearly defined.

[0036] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0037] Example 1

[0038] 1) Preparation of acrylic emulsion

[0039] Take 30 parts of deionized water, add AF-1500 defoaming agent 1 part, BYK-2199 dispersant 1 part, stir evenly, then add rutile titanium dioxide 50 parts, kaolin powder 10 parts, stir and disperse into paste, add 2 parts of hydroxyethyl cellulose thickener, BYK-333 wetting leveling agent 1 part and AF-1500 defoaming agent 1 part, stir evenly, then add cationic acrylic resin emulsion with hydroxyl value of 2 mgKOH / g 50 parts, stir evenly to obtain the required acrylic emulsion;

[0040] 2) Preparation of curing agent

[0041] Take 30 parts of basic silica sol with particle size of 30 nm, dilute with 40 parts of deionized water, add a mixture of 24 parts of methyl triethoxysilane, 16 parts of γ-(2, 3-epoxy propoxy) propyl trimethoxysilane and 1 part of acetic acid under stirring conditions, stir for 10 h, the solution gradually reacts from turbid two-phase solution to uniform single phase, and the aqueous solution changes from basic to acidic;

[0042] 3) Mix the acrylic emulsion obtained in step 1) with the curing agent obtained in step 2) according to a mass ratio of 10:4 to obtain the required low-temperature curing photovoltaic glass white glaze. Apply the glaze on the glass, and after curing at room temperature for 10 h, a high-reflective coating is obtained.

[0043] Example 2

[0044] 1) Preparation of acrylic emulsion

[0045] Take 30 parts of deionized water, add defoaming agent 1 part, dispersant 1 part, stir evenly, then add rutile titanium dioxide 50 parts, kaolin powder 10 parts, stir and disperse into paste, add thickener 2 parts, wetting leveling agent 1 part and defoaming agent 1 part, stir evenly, then add cationic acrylic resin emulsion with hydroxyl value of 2 mgKOH / g 50 parts, stir evenly to obtain the required acrylic emulsion;

[0046] 2) Preparation of curing agent

[0047] Take 30 parts of basic silica sol, dilute with 40 parts of deionized water, add a mixture of 24 parts of methyl triethoxysilane, 16 parts of γ-(2, 3-epoxy propoxy) propyl trimethoxysilane and 1 part of acetic acid under stirring conditions, stir for 10 h, the solution gradually reacts from turbid two-phase solution to uniform single phase, and the aqueous solution changes from basic to acidic;

[0048] 3) The acrylic emulsion obtained in step 1) and the curing agent obtained in step 2) are mixed in a mass ratio of 10:10 to obtain the desired low-temperature curing white glaze for photovoltaic glass, which is coated on the glass, and a high-reflective coating is obtained after curing at room temperature for 10 h.

[0049] The rest is the same as in Example 1.

[0050] Comparative Example 1

[0051] 1) Preparation of the acrylic emulsion

[0052] In parts by weight, 30 parts of deionized water are weighed, and 1 part of defoaming agent and 1 part of dispersant are sequentially added. After stirring uniformly, 50 parts of rutile titanium dioxide and 10 parts of kaolin powder are added and stirred and dispersed into a paste. Then, 2 parts of thickening agent, 1 part of wetting and leveling agent, and 1 part of defoaming agent are added and stirred uniformly. Finally, 50 parts of cationic acrylic resin emulsion with a hydroxyl value of 2 mgKOH / g are added and stirred uniformly to obtain the desired acrylic emulsion.

[0053] 2) Preparation of the curing agent

[0054] 30 parts of alkaline silica sol are weighed and diluted with 40 parts of deionized water. Under stirring conditions, 40 parts of a mixture of methyltriethoxysilane and 1 part of acetic acid are added, and stirring is performed for 10 h.

[0055] 3) The acrylic emulsion obtained in step 1) and the curing agent obtained in step 2) are mixed in a mass ratio of 10:4 to obtain the white glaze, which is coated on the glass, and a reflective coating is obtained after curing at room temperature for 10 h.

[0056] The rest is the same as in Example 1.

[0057] The coatings obtained in Comparative Examples 1-2 and Example 1 are tested for performance, and the results are shown in Table 1. Figure 1 The high-reflective coating of Example 2 is a broad-spectrum curve diagram.

[0058] Table 1

[0059]

[0060] From Table 1 and Figure 1It can be seen that the high-reflective coating obtained in Example 1-2 has excellent high-temperature resistance, and the high-reflective coating obtained in Example 1-2 has good adhesion with the glass, which can reach 0 level, because the unhydrolyzed siloxane contained in the curing agent in the curing process condenses with the hydroxyl group on the surface of the glass to produce firm chemical bonding; compared with Example 1, the coating of Comparative Example 1 has significantly lower average reflectivity in the wavelength range of 380-1200 nm and 380-1100 nm, because the siloxane resins of Comparative Example 1 and Example 1 are different, so that the curing agent system is different, Comparative Example 1 completely uses methyl triethoxysilane modified silica, because it has certain hydrophobicity in the curing process, which leads to poor performance of filling the powder accumulation gap, while Example 1 uses a mixture of methyl triethoxysilane and γ-(2,3-epoxypropoxy) propyl trimethoxysilane to modify the silica, which improves the performance of filling the powder accumulation gap and improves the average reflectivity, which means that the type of curing agent has an effect on the reflectivity of the coating, only using a mixture of methyl triethoxysilane and γ-(2,3-epoxypropoxy) propyl trimethoxysilane to modify the silica can improve the reflectivity of the coating, and methyl triethoxysilane and γ-(2,3-epoxypropoxy) propyl trimethoxysilane are indispensable; compared with Example 1, the average reflectivity of Example 2 in the wavelength range of 380-1100 nm and 380-1200 nm is higher, which is the effect of adding more curing agent, which means that the amount of curing agent has an effect on the reflectivity of the coating, and adding an appropriate amount of curing agent can better fill the gap generated in the curing of the powder and improve the reflectivity of light.

[0061] The parts or structures not specifically described in the present application can be realized by using the prior art or existing products, which will not be described here.

[0062] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation using the content of the present application specification, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A low temperature sintering photovoltaic glass white enamel characterized in that, The white glaze is prepared by an acrylic emulsion and a curing agent, the acrylic emulsion is prepared from raw materials including rutile titanium dioxide and cationic acrylic resin emulsion, and the curing agent is prepared from raw materials including silica and siloxane resin; The raw materials for preparing the acrylic emulsion include the following components in parts by weight: Rutile titanium dioxide 50-100 parts Cationic acrylic resin emulsion 40-60 parts Kaolin powder 5-15 parts Deionized water 30-50 parts Defoaming agent 1-2 parts Dispersant 1-2 parts Thickening agent 1-2 parts Wetting and leveling agent 0.5-1 part The raw materials for preparing the curing agent include the following components in parts by weight: Alkaline silica sol 30-40 parts Siloxane resin 30-40 parts Deionized water 30-40 parts Acetic acid 0.25-1 part The siloxane resin is a mixture of methyl triethoxysilane and γ-(2,3-epoxypropoxy) propyl trimethoxysilane, and the mass ratio of methyl triethoxysilane to γ-(2,3-epoxypropoxy) propyl trimethoxysilane is 1:0.67-2.

2. A low temperature sintering photovoltaic glass white enamel according to claim 1, characterized in that, The cationic acrylic resin emulsion has a hydroxyl value of 1.5-2 mgKOH / g and a minimum film formation temperature of 15-25℃.

3. A low temperature sintering photovoltaic glass white enamel according to claim 1, characterized in that, The alkaline silica sol has a particle size of 30-40 nm.

4. A low temperature sintering photovoltaic glass white enamel according to claim 1, characterized in that, The mass ratio of the acrylic emulsion to the curing agent is 10:4-10.

5. A method of making a low temperature sintering photovoltaic glass white enamel according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: 1) Preparation of the acrylic emulsion Weigh the deionized water, add part of the defoaming agent and all of the dispersant, stir until uniform, then add the rutile titanium dioxide and kaolin powder, stir until dispersed into a paste, then add the thickening agent, wetting and leveling agent, and the remaining defoaming agent, stir until uniform, then add the cationic acrylic resin emulsion, stir until uniform, and the desired acrylic emulsion is obtained; 2) Preparation of the curing agent Weigh the alkaline silica sol, dilute with deionized water, and add the mixture of siloxane resin and acetic acid under stirring, stir until uniform, then the solution gradually changes from turbid two-phase to uniform single-phase, and the solution changes from alkaline to acidic, and the desired curing agent is obtained; 3) Mix the acrylic emulsion obtained in step 1) and the curing agent obtained in step 2) according to a certain mass ratio, and the desired low-temperature curing white glaze for photovoltaic glass is obtained.

6. A high reflectance coating characterized by, The low-temperature curing white glaze for photovoltaic glass is prepared by curing the low-temperature curing white glaze for photovoltaic glass according to any one of claims 1-5 at a low temperature for a certain period of time.

7. A high reflectance coating according to claim 6, wherein The certain period of time for low-temperature curing is 10-15 min at 70℃-80℃, or 6-12 h at room temperature 20℃-25℃.

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