Yellowing-resistant glue, preparation method thereof and photovoltaic module

Abstract

The embodiment of the invention relates to the field of photovoltaics, and provides anti-yellowing glue, a preparation method thereof and a photovoltaic module, the glue is prepared from the following raw materials in parts by weight: 50-85 parts of an acrylate copolymer, 20-40 parts of a functional monomer, 7-14 parts of an active diluent and 2-7 parts of a photoinitiator, 0.1 to 1 part by weight of an auxiliary agent; wherein the reactive diluent is one of dipentaerythritol hexaacrylate or ethoxylated bisphenol A diacrylate or a mixture of dipentaerythritol hexaacrylate and ethoxylated bisphenol A diacrylate. According to the glue and the preparation method thereof provided by the embodiment of the invention, the glue applied to the photovoltaic module is not easy to yellow, so that relatively high transmittance can be ensured, and the photoelectric conversion efficiency of a solar cell in the photovoltaic module is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the photovoltaic field, and in particular to a yellowing-resistant glue and a preparation method thereof, and a photovoltaic module. Background Art

[0002] At present, with the gradual depletion of fossil energy, solar cells are becoming more and more widely used as a new energy alternative. Solar cells are devices that convert sunlight into electrical energy. Solar cells use the photovoltaic principle to generate carriers, and then use electrodes to lead the carriers out, thereby facilitating the effective use of electrical energy.

[0003] In the process of assembling solar cells into photovoltaic modules and multiple solar panels, positioning tapes and positioning glues are often needed. For example, in conventional main grid-free cells, since the welding tape needs to be welded to the fine grid, and the extension direction of the welding tape and the fine grid is different, positioning glue is needed to improve the problem of insufficient welding tension in the cell. However, it is found that the positioning tapes and glues currently used are easy to deform under 150°C lamination conditions and in subsequent long-term use, and there is a phenomenon of yellowing and reduced transmittance, thereby blocking the effective area of ​​light energy conversion, resulting in reduced component power of photovoltaic modules. Summary of the invention

[0004] The embodiments of the present application provide a yellowing-resistant glue and a preparation method thereof, and a photovoltaic module, which are at least helpful in solving the problem of optical loss caused by yellowing of the glue layer composed of the glue during use.

[0005] According to some embodiments of the present application, on the one hand, the embodiments of the present application provide a yellowing-resistant glue, which is prepared from raw materials measured in parts by weight: 50 to 85 parts by weight of an acrylate copolymer, 20 to 40 parts by weight of a functional monomer, 7 to 14 parts by weight of an active diluent, 2 to 7 parts by weight of a photoinitiator, and 0.1 to 1 part by weight of an auxiliary agent; wherein the active diluent is dipentaerythritol hexaacrylate or ethoxylated bisphenol A diacrylate, or a mixture of several of them.

[0006] In some embodiments, the active diluent is composed of dipentaerythritol hexaacrylate and ethoxylated bisphenol A diacrylate; wherein, in parts by weight, the weight of dipentaerythritol hexaacrylate is 4 to 8 parts, and the weight of ethoxylated bisphenol A diacrylate is 3 to 6 parts.

[0007] In some embodiments, the photoinitiator is diphenyl (2,4,6-triformyl) phosphine oxide (TPO), methyl benzoylformate (MBF), 2-hydroxy-2-methyl-1-phenylpropanone (1173), 1-hydroxycyclohexyl phenyl ketone (907), ethyl 2,4,6-trimethylbenzoyl phenylphosphonate (TPO-L), 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (659), benzoin butyl ether, diphenylacetophenone, 1-hydroxycyclohexyl phenyl ketone (184), 4,a-dimethoxy-a-phenylacetophenone, a,a-diethoxybenzophenone, a-hydroxyalkylbenzophenone, a-aminoalkylbenzophenone, aromatic acylphosphine oxide, benzophenone, 2,4-dihydroxybenzophenone, Michler's ketone, thiopropoxythiophenone, isopropylthiophenone, or a mixture of several thereof.

[0008] In some embodiments, the photoinitiator is composed of diphenyl (2,4,6-triformyl) phosphine oxide (TPO) and methyl benzoylformate (MBF), wherein, in parts by weight, the weight portion of diphenyl (2,4,6-triformyl) phosphine oxide is 1 to 4 parts, and the weight portion of methyl benzoylformate is 1 to 3 parts.

[0009] In some embodiments, the functional monomer includes one or a mixture of dimethylaminoethyl methacrylate, hexanediol diacrylate, acrylamide (AAM), hydroxymethyl acrylamide (NMA), diacetone acrylamide (DAAM), ethyl acetoacetate methacrylate (AAEM), glycidyl methacrylate (GMA), dimethylaminoethyl methacrylate (DMAEMA) and vinyl siloxanes.

[0010] In some embodiments, the functional monomer is composed of dimethylaminoethyl methacrylate and hexamethylene glycol diacrylate; wherein, in parts by weight, the weight of dimethylaminoethyl methacrylate is 10 to 20 parts, and the weight of hexamethylene glycol diacrylate is 10 to 20 parts.

[0011] In some embodiments, the acrylic copolymer is polymerized from one or more olefinic monomers or one or more acrylic monomers.

[0012] In some embodiments, the molecular weight of the acrylic copolymer is 480 g / mol to 640 g / mol.

[0013] In some embodiments, the acrylic copolymer is prepared from the following raw materials in parts by weight: 25 to 35 parts by weight of methyl methacrylate, 5 to 10 parts by weight of styrene, 20 to 25 parts by weight of hydroxyethyl methacrylate, and 8 to 12 parts by weight of lauryl acrylate.

[0014] In some embodiments, the auxiliary agent includes silicone oil, polydimethylsiloxane, polyether polyester modified organic siloxane, alkyl modified organic siloxane, acrylic leveling agent or fluorine modified leveling agent.

[0015] In some embodiments, the glue has a glass transition temperature of 70° C. to 110° C. and a molecular weight of 800 g / mol to 1500 g / mol.

[0016] According to some embodiments of the present application, on the other hand, the embodiments of the present application also provide a method for preparing glue, comprising: stirring and evenly mixing 50 to 85 parts by weight of an acrylate copolymer, 7 to 14 parts by weight of an active diluent, and 0.1 to 1 part by weight of an auxiliary agent in a light-proof environment; wherein the active diluent is dipentaerythritol hexaacrylate or ethoxylated bisphenol A diacrylate or a mixture of one or more of them; adding 20 to 40 parts by weight of a functional monomer in a light-proof environment, and continuing to stir until the functional monomers are evenly mixed; slowly adding 2 to 7 parts by weight of a photoinitiator at a preset dripping rate in a light-proof environment, and continuing to stir until the photoinitiator is evenly mixed.

[0017] According to some embodiments of the present application, on the other hand, the embodiments of the present application further provide a photovoltaic module, including: a busbar-free cell, a welding strip and an adhesive layer; the adhesive layer is used to fix the welding strip and the busbar-free cell, and the adhesive layer is formed by ultraviolet light curing of the glue described in any one of the above embodiments or the glue prepared by the preparation method described in the above embodiments.

[0018] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0019] In the technical solution provided in the embodiment of the present application, a reactive diluent is added to the formula of the glue, and this reactive diluent can improve the stability of the glue and prevent the glue from yellowing in subsequent operations and during use. Wherein, the reactive diluent is dipentaerythritol hexaacrylate and ethoxylated bisphenol A diacrylate. Dipentaerythritol hexaacrylate has four hydroxyl groups that play a role, and then a more stable network structure can be formed, so that it is not easy to decompose and further react, and the stability of the formed glue is higher. The ethoxy group in ethoxylated bisphenol A diacrylate makes the acrylate glue flexible, and it also has bisphenol A chain links, which can make the structural stability of the formed polymer higher and the molecular weight larger, and the volatility is reduced, so that it is not easy to further decompose under high temperature and ultraviolet light stimulation, so that it has higher stability and heat resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] One or more embodiments are exemplarily illustrated by the figures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, the figures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present application or the technical solutions in the traditional technology, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic structural diagram of a mold used for testing the glue provided in one embodiment of the present application. DETAILED DESCRIPTION

[0022] As can be seen from the background technology, the current glue has the problems of yellowing and low light transmittance.

[0023] The embodiments of the present application provide a formula of glue, a preparation method and a photovoltaic module containing the glue. By improving the formula of the glue and adding active diluents such as dipentaerythritol hexaacrylate or ethoxylated bisphenol A diacrylate, the glue can have better yellowing resistance, thereby increasing the module power of the photovoltaic module.

[0024] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0025] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0027] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0028] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0029] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0030] In the accompanying drawings corresponding to the embodiments of the present application, the thickness and area of ​​the layer are magnified for better understanding and ease of description. When describing a component (such as a layer, film, region or substrate) on another component or on the surface of another component, the component can be "directly" located on the surface of another component, or there can be a third component between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0031] In the description of the embodiments of the present application, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, film, region, or plate is referred to as being "on / located on" another component, it may be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may exist in between. In addition, when a component such as a layer, film, region, or plate is "directly located on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it means that no other components are located in between.

[0032] The terms used in the description of the various embodiments described herein are only used to describe specific embodiments and are not intended to be limiting. As used in the description of the various embodiments described and in the appended claims, "the part" is also intended to include the plural form unless the context clearly indicates otherwise. Among them, a component includes a layer, a film, a region, or a plate.

[0033] The following will describe the various embodiments of the present application in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present application, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solution claimed in the present application can be implemented.

[0034] According to some embodiments of the present application, on the one hand, the embodiments of the present application provide a yellowing-resistant glue. The glue is prepared from raw materials in parts by weight: 50 to 85 parts by weight of an acrylate copolymer, 20 to 40 parts by weight of a functional monomer, 7 to 14 parts by weight of an active diluent, 2 to 7 parts by weight of a photoinitiator, and 0.1 to 1 part by weight of an auxiliary agent; wherein the active diluent is dipentaerythritol hexaacrylate or ethoxylated bisphenol A diacrylate, or a mixture of several of them.

[0035] In the glue provided by the embodiment of the present application, a reactive diluent is added to the formula of the glue, and this reactive diluent can improve the stability of the glue and prevent the glue from yellowing in subsequent operations and during use. Wherein, the reactive diluent is dipentaerythritol hexaacrylate and ethoxylated bisphenol A diacrylate. Dipentaerythritol hexaacrylate has four hydroxyls to play a role, and then a more stable network structure can be formed, so that it is not easy to decompose and further react, and the stability of the formed glue is higher. The ethoxy group in ethoxylated bisphenol A diacrylate makes the acrylate glue flexible, and also has bisphenol A chain links, which can make the structural stability of the formed polymer higher and the molecular weight larger, and the volatility is reduced, so that it is not easy to further decompose under high temperature and ultraviolet light stimulation, so that it has higher stability and heat resistance.

[0036] In some embodiments, the acrylic copolymer is polymerized from one or more acrylate monomers or one or more acrylic monomers.

[0037] The olefinic monomer refers to a monomer having an olefin bond (C=C) and a carboxyl group (COOH) as a functional group, and the olefinic monomer may be an acrylic acid monomer or a crotonic acid monomer.

[0038] The acrylic monomer may be methyl methacrylate, methyl acrylate, isobornyl methacrylate, isobornyl acrylate, butyl acrylate, ethyl acrylate, isooctyl acrylate, acrylic acid, glycidyl methacrylate, hydroxyethyl methacrylate, lauryl acrylate or hydroxyethyl acrylate.

[0039] The butenoic acid monomers may be butenoic acid, methyl methacrylate or ethyl 2-butenoate.

[0040] Acrylate copolymers can be produced through reactants such as hard monomers, soft monomers or functional monomers. For example, hard monomers can be methyl methacrylate, methyl acrylate, isobornyl methacrylate, isobornyl acrylate, styrene, acrylonitrile, etc.; soft monomers can be butyl acrylate, ethyl acrylate, isooctyl acrylate; functional monomers can be hydroxyethyl acrylate, acrylic acid, glycidyl methacrylate, acrylamide, etc.

[0041] In some embodiments, the acrylic copolymer is prepared from the following raw materials in parts by weight: 25 to 35 parts by weight of methyl methacrylate, 5 to 10 parts by weight of styrene, 20 to 25 parts by weight of hydroxyethyl methacrylate, and 8 to 12 parts by weight of lauryl acrylate. Among them, methyl methacrylate and styrene are used as hard monomers, lauryl acrylate is a soft monomer, and hydroxyethyl methacrylate is used as both a soft monomer and a functional monomer.

[0042] In some embodiments, the molecular weight (relative molecular weight) of the acrylic copolymer is 480 g / mol to 640 g / mol. For example, the molecular weight of the acrylic copolymer is 481 g / mol, 493 g / mol, 520 g / mol, 543 g / mol, 574.789 g / mol, 592 g / mol, 603 g / mol, 618 g / mol, or 639 g / mol.

[0043] The molecular weight may refer to the average molecular weight or average relative molecular weight of the acrylic copolymer. Depending on the statistical method, the average relative molecular weight can be expressed in four different ways: number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz), and viscosity average molecular weight (Mη). The number average molecular weight (Mn) is the average molecular weight calculated based on the number of molecules or the amount of substance; the weight average molecular weight (Mw) is the average molecular weight of the polymer calculated based on the mass; the Z average molecular weight (Mz) is the average molecular weight calculated based on the Z amount; and the viscosity average molecular weight (Mη) is the average molecular weight measured by the solution viscosity method.

[0044] In some embodiments, the functional monomer includes one or a mixture of dimethylaminoethyl methacrylate, hexanediol diacrylate, acrylamide (AAM), hydroxymethyl acrylamide (NMA), diacetone acrylamide (DAAM), ethyl acetoacetate methacrylate (AAEM), glycidyl methacrylate (GMA), dimethylaminoethyl methacrylate (DMAEMA) and vinyl siloxanes.

[0045] In some embodiments, the functional monomer is composed of dimethylaminoethyl methacrylate and hexamethylene glycol diacrylate; wherein, in parts by weight, the weight of dimethylaminoethyl methacrylate is 10 to 20 parts, and the weight of hexamethylene glycol diacrylate is 10 to 20 parts.

[0046] Reactive diluents generally refer to monomers or functional monomers in the reaction system, which refers to small organic molecules containing polymerizable functional groups. In the formulation of photocurable adhesives, reactive diluents not only dissolve and dilute oligomers and adjust the viscosity of the system, but also participate in the photocuring process, affecting the photocuring rate of the photocurable product and the various properties of the film finally formed.

[0047] In some embodiments, the active diluent is composed of dipentaerythritol hexaacrylate and ethoxylated bisphenol A diacrylate; wherein, in parts by weight, the weight of dipentaerythritol hexaacrylate is 4 to 8 parts, and the weight of ethoxylated bisphenol A diacrylate is 3 to 6 parts.

[0048] In some embodiments, the photoinitiator is diphenyl (2,4,6-triformyl) phosphine oxide (TPO), methyl benzoylformate (MBF), 2-hydroxy-2-methyl-1-phenylpropanone (1173), 1-hydroxycyclohexyl phenyl ketone (907), ethyl 2,4,6-trimethylbenzoyl phenylphosphonate (TPO-L), 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (659), benzoin butyl ether, diphenylacetophenone, 1-hydroxycyclohexyl phenyl ketone (184), 4,a-dimethoxy-a-phenylacetophenone, a,a-diethoxybenzophenone, a-hydroxyalkyl benzophenone, a-aminoalkyl benzophenone, aromatic acylphosphine oxide, benzophenone, 2,4-dihydroxybenzophenone, Michler's ketone, thiopropoxythiophenone, isopropylthiophenone, or a mixture of several thereof.

[0049] In some embodiments, the photoinitiator is composed of diphenyl (2,4,6-triformyl) phosphine oxide (TPO) and methyl benzoylformate (MBF), wherein, in parts by weight, the weight proportion of diphenyl (2,4,6-triformyl) phosphine oxide is 1 to 4 parts, and the weight proportion of methyl benzoylformate is 1 to 3 parts.

[0050] In some embodiments, the auxiliary agent includes silicone oil, polydimethylsiloxane, polyether polyester modified organic siloxane, alkyl modified organic siloxane, acrylic leveling agent or fluorine modified leveling agent.

[0051] In some embodiments, the glass transition temperature of the glue is 70° C. to 110° C., and the molecular weight is 800 g / mol to 1500 g / mol.

[0052] For example, the glass transition temperature of the glue is 70° C., 76° C., 81° C., 83° C., 88° C., 92° C., 95° C., 101° C., or 109° C. The molecular weight of the glue is 802 g / mol, 831 g / mol, 880 g / mol, 913 g / mol, 958.26 g / mol, 983 g / mol, 1021 g / mol, 1154 g / mol, 1321 g / mol, or 1500 g / mol.

[0053] The technical solution of the present application is further described below by means of specific implementation methods. It should be understood by those skilled in the art that the embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0054] Examples 1 to 9 each include a yellowing-resistant glue, which is prepared from the following raw materials by weight, as shown in Table 1:

[0055] Table 1

[0056]

[0057]

[0058] The acrylic copolymers in Examples 1 to 9 are all polymerized from 25 parts of methyl methacrylate, 8 parts of styrene, 20 parts of hydroxyethyl methacrylate and 10 parts of lauryl acrylate, and the molecular weight of the acrylic copolymer is 574 g / mol.

[0059] The functional monomers consist of 15 parts of dimethylaminoethyl methacrylate and 15 parts of hexanediol diacrylate.

[0060] The photoinitiator consisted of 1.5 parts of diphenyl(2,4,6-triformyl)phosphine oxide (TPO) and 1.5 parts of methyl benzoylformate (MBF).

[0061] The leveling agent is dodecylsiloxane.

[0062] Comparative Examples 1 to 5 each include a yellowing-resistant glue, which is prepared from the following raw materials by weight, as shown in Table 2:

[0063] Table 2

[0064]

[0065]

[0066] The acrylic copolymers, functional monomers, photoinitiators and leveling agents in Comparative Examples 1 to 5 are the same as those in Example 1, and are not described in detail here.

[0067] The glue provided in the above-mentioned Examples 1 to 9 and Comparative Examples 1 to 5 was subjected to performance testing, and the specific method is as follows:

[0068] 1. Prepare a test sample, the thickness of the test sample is 450 μm.

[0069] Provide molds for preparing test samples, such as Figure 1 As shown, the mold includes two upper and lower transparent glass plates, the size of the transparent glass plates is a 10 cm×10 cm square, and then a 5 cm×5 cm square is cut in the middle of one of the transparent glass plates to accommodate the test sample.

[0070] Place a release film on a 40cm×40cm transparent glass plate with the oil side facing upward, place the prepared mold in the middle, squeeze the test sample into a 5cm×5cm square, then cover it with the release film with the oil side facing downward, and then cover it with a second 40cm×40cm transparent glass, and press down hard; finally, irradiate it with a UV lamp for 5S to make a cured test sample, and the thickness of the prepared test sample is 450μm.

[0071] 2. Test Method

[0072] 2.1 Yellowing test method

[0073] (1) Using a colorimeter, measure the b values ​​of Examples 1 to 9 and Comparative Examples 1 to 5 respectively, and record them as b1 respectively;

[0074] (2) After the test samples were packaged in a small assembly and baked at 200° C. for 3 hours, the b values ​​of Examples 1 to 9 and Comparative Examples 1 to 5 were measured using a colorimeter and recorded as b2 respectively;

[0075] (3) Based on b1 and b2, calculate Δb=b2-b1.

[0076] 2.2 Transmittance test method

[0077] (1) Using a colorimeter, measure the T values ​​of Examples 1 to 9 and Comparative Examples 1 to 5 respectively, and record them as T1 respectively;

[0078] (2) After the test samples were packaged in a small assembly and baked at 200° C. for 3 hours, the T values ​​of Examples 1 to 9 and Comparative Examples 1 to 5 were measured using a colorimeter and recorded as T2;

[0079] (3) Based on T1 and T2, calculate ΔT=T2-T1.

[0080] 3. Test results

[0081] The test results are shown in Table 3, which shows that the formula of the photovoltaic glue provided in the embodiment of the present application has good yellowing resistance.

[0082] Table 3

[0083] Components Yellowing △b Transmittance △T Example 1 2.33 3.17 Example 2 2.28 2.88 Example 3 2.36 3.41 Example 4 2.52 4.71 Example 5 2.47 3.85 Example 6 3.95 4.47 Example 7 0.68 1.04 Example 8 1.74 1.96 Example 9 2.56 1.72 Comparative Example 1 4.21 3.55 Comparative Example 2 4.74 3.92 Comparative Example 3 5.02 4.33 Comparative Example 4 4.54 2.89 Comparative Example 5 5.79 4.16

[0084] It can be seen from Table 3 that the addition of dipentaerythritol hexaacrylate or ethoxylated bisphenol A diacrylate can improve the yellowing resistance of the glue. From the data of Examples 1 to 3 or Examples 4 to 6 and Comparative Examples 4-5, it can be seen that with the increase in the content of dipentaerythritol hexaacrylate or ethoxylated bisphenol A diacrylate, the yellowing and light transmittance show a trend of first decreasing and then increasing. From the data of Examples 1 to 9, it can be seen that when two active diluents (dipentaerythritol hexaacrylate and ethoxylated bisphenol A diacrylate) are added, the yellowing and light transmittance are better than the yellowing and light transmittance of only adding one active diluent, and the data of Example 7 is the best, that is, the amount of dipentaerythritol hexaacrylate is greater than the amount of ethoxylated bisphenol A diacrylate.

[0085] Examples 10 to 14 are the same as Example 7 except for the different photoinitiators. The difference is that each of Examples 10 to 14 includes a yellowing-resistant glue, which is prepared from the following raw materials by weight, as shown in Table 4:

[0086] Table 4

[0087]

[0088] Comparative Examples 6 to 8 each include a yellowing-resistant glue, which is prepared from the following raw materials by weight, as shown in Table 5:

[0089] Table 5

[0090]

[0091]

[0092] The acrylic copolymers, functional monomers, photoinitiators and leveling agents in Comparative Examples 6 to 8 are the same as those in Example 10, and are not described in detail here.

[0093] The glue provided in the above-mentioned Examples 10 to 14 and Comparative Examples 6 to 8 was subjected to the same performance test as in Example 1. The test results are shown in Table 6. Table 6 shows that the formula of the photovoltaic glue provided in the examples of the present application has good yellowing resistance.

[0094] Table 6

[0095] Components Yellowing △b Transmittance △T Implementation 7 0.68 1.04 Example 10 3.79 2.86 Embodiment 11 2.54 2.17 Example 12 2.82 2.09 Example 13 1.77 1.52 Embodiment 14 1.43 1.33 Comparative Example 6 6.59 3.92 Comparative Example 7 5.73 3.88 Comparative Example 8 4.94 2.85

[0096] It can be seen from Table 6 that the addition of diphenyl (2,4,6-triformyl) phosphine oxide and methyl benzoylformate can improve the yellowing resistance of the glue. From the data of Examples 10 to 13 and Comparative Examples 6-8, it can be seen that with the increase of the content of diphenyl (2,4,6-triformyl) phosphine oxide or methyl benzoylformate, the yellowing and light transmittance show a trend of first decreasing and then increasing. From the data of Examples 7 to 14, it can be seen that the addition of two photoinitiators (diphenyl (2,4,6-triformyl) phosphine oxide and methyl benzoylformate) has better yellowing and light transmittance than the addition of only one photoinitiator, and the data of Example 7 is the best.

[0097] In the glue provided by the embodiment of the present application, a reactive diluent is added to the formula of the glue, and this reactive diluent can improve the stability of the glue and prevent the glue from yellowing in subsequent operations and during use. Wherein, the reactive diluent is dipentaerythritol hexaacrylate and ethoxylated bisphenol A diacrylate. Dipentaerythritol hexaacrylate has four hydroxyls to play a role, and then a more stable network structure can be formed, so that it is not easy to decompose and further react, and the stability of the formed glue is higher. The ethoxy group in ethoxylated bisphenol A diacrylate makes the acrylate glue flexible, and also has bisphenol A chain links, which can make the structural stability of the formed polymer higher and the molecular weight larger, and the volatility is reduced, so that it is not easy to further decompose under high temperature and ultraviolet light stimulation, so that it has higher stability and heat resistance.

[0098] Correspondingly, according to some embodiments of the present application, on the other hand, the embodiments of the present application also provide a method for preparing glue, comprising: stirring and mixing 50 to 85 parts by weight of an acrylate copolymer, 7 to 14 parts by weight of an active diluent, and 0.1 to 1 part by weight of an auxiliary agent in a light-proof environment; wherein the active diluent is dipentaerythritol hexaacrylate or ethoxylated bisphenol A diacrylate or a mixture of one or more of them; adding 20 to 40 parts by weight of a functional monomer in a light-proof environment, and continuing to stir until the functional monomers are evenly mixed; slowly adding 2 to 7 parts by weight of a photoinitiator at a preset dripping rate in a light-proof environment, and continuing to stir until the photoinitiator is evenly mixed.

[0099] In some embodiments, the preset dripping rate is 1 drop / s to 2 drops / s.

[0100] Correspondingly, according to some embodiments of the present application, on the other hand, the embodiments of the present application further provide a photovoltaic module, including: a busbarless cell, a welding strip and an adhesive layer; the adhesive layer is used to fix the welding strip and the busbarless cell, and the adhesive layer is formed by ultraviolet light curing of the glue of any one of the above embodiments or the glue prepared by the preparation method of the above embodiments.

[0101] The effects of the photovoltaic components provided by the above embodiments will be further described below in conjunction with related embodiments.

[0102] Examples 15 to 19 also provide a glue which is the same as Example 7 except that the monomer of the acrylic copolymer is different. The difference is that the acrylic copolymer in Examples 15 to 19 is prepared from the following raw materials in parts by weight, as shown in Table 7:

[0103] Table 7

[0104]

[0105] The glue provided in the above-mentioned embodiments 15 to 19 is subjected to the same test as in embodiment 1, and the glass transition temperature is obtained based on the instrument, and the glue is applied to the photovoltaic module for welding tensile test. The specific method is as follows: the battery cell together with the welding ribbon is cut off, and a tensile test is performed using a welding ribbon-battery cell tensile machine for photovoltaic modules, and the welding ribbon is stretched 180° in the opposite direction to make the welding ribbon fall off the battery cell and the tensile value is read and recorded.

[0106] The test results are shown in Table 8.

[0107] Table 8

[0108]

[0109] It should be noted that embodiments 1 to 14 can all be used for welding tensile test, and the present application uses embodiments 1, 7 and 14 as examples. That is to say, the glue provided in the present application embodiment can have good anti-yellowing ability and provide good welding tensile force.

[0110] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present application, and in practical applications, various changes may be made to the embodiments in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present application, and therefore the scope of protection of the present application shall be subject to the scope defined in the claims.

Claims

1. A yellowing-resistant glue, characterized in that: The glue is prepared from the following raw materials in parts by weight: 50 to 85 parts by weight of an acrylic copolymer, 20 to 40 parts by weight of a functional monomer, 7 to 14 parts by weight of an active diluent, 2 to 7 parts by weight of a photoinitiator, and 0.1 to 1 part by weight of an auxiliary agent; wherein the active diluent is dipentaerythritol hexaacrylate or ethoxylated bisphenol A diacrylate, or a mixture of several of them.

2. The glue according to claim 1, characterized in that The active diluent is composed of dipentaerythritol hexaacrylate and ethoxylated bisphenol A diacrylate; wherein, in parts by weight, the weight of the dipentaerythritol hexaacrylate is 4 to 8 parts, and the weight of the ethoxylated bisphenol A diacrylate is 3 to 6 parts.

3. The glue according to claim 1, characterized in that The photoinitiator is one of diphenyl (2,4,6-triformyl) phosphine oxide (TPO), methyl benzoylformate (MBF), 2-hydroxy-2-methyl-1-phenylpropanone (1173), 1-hydroxycyclohexyl phenyl ketone (907), ethyl 2,4,6-trimethylbenzoyl phenylphosphonate (TPO-L), 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (659), benzoin butyl ether, diphenylacetophenone, 1-hydroxycyclohexyl phenyl ketone (184), 4,a-dimethoxy-a-phenylacetophenone, a,a-diethoxybenzophenone, a-hydroxyalkyl benzophenone, a-aminoalkyl benzophenone, aromatic acylphosphine oxide, benzophenone, 2,4-dihydroxybenzophenone, Michler's ketone, thiopropoxythioanthraquinone, isopropylthioanthraquinone, or a mixture of several thereof.

4. The glue according to claim 3, characterized in that: The photoinitiator is composed of diphenyl (2,4,6-triformyl) phosphine oxide (TPO) and methyl benzoylformate (MBF), wherein, in parts by weight, the weight of the diphenyl (2,4,6-triformyl) phosphine oxide is 1 to 4 parts, and the weight of the methyl benzoylformate is 1 to 3 parts.

5. The glue according to claim 1, characterized in that: The functional monomers include one or a mixture of dimethylaminoethyl methacrylate, hexanediol diacrylate, acrylamide (AAM), hydroxymethyl acrylamide (NMA), diacetone acrylamide (DAAM), ethyl acetoacetate methacrylate (AAEM), glycidyl methacrylate (GMA), dimethylaminoethyl methacrylate (DMAEMA) and vinyl siloxanes.

6. The glue according to claim 5, characterized in that The functional monomer is composed of dimethylaminoethyl methacrylate and hexamethylene glycol diacrylate; wherein, in parts by weight, the weight of dimethylaminoethyl methacrylate is 10 to 20 parts, and the weight of hexamethylene glycol diacrylate is 10 to 20 parts.

7. The glue according to claim 1, characterized in that The acrylic ester copolymer is polymerized from one or more olefinic monomers or one or more acrylic ester monomers.

8. The glue according to claim 1, characterized in that The molecular weight of the acrylic ester copolymer is 480 g / mol to 640 g / mol.

9. The glue according to claim 1 or 8, characterized in that: The acrylic ester copolymer is prepared from the following raw materials in parts by weight: 25 to 35 parts by weight of methyl methacrylate, 5 to 10 parts by weight of styrene, 20 to 25 parts by weight of hydroxyethyl methacrylate, and 8 to 12 parts by weight of lauryl acrylate.

10. The glue according to claim 4, characterized in that: The auxiliary agent includes silicone oil, polydimethylsiloxane, polyether polyester modified organic siloxane, alkyl modified organic siloxane, acrylic leveling agent or fluorine modified leveling agent.

11. The glue according to claim 4, characterized in that The glass transition temperature of the glue is 70° C. to 110° C., and the molecular weight is 800 g / mol to 1500 g / mol.

12. A method for preparing glue, characterized in that: include: Stir and mix 50 to 85 parts by weight of an acrylic copolymer, 7 to 14 parts by weight of an active diluent, and 0.1 to 1 part by weight of an auxiliary agent in a light-proof environment; wherein the active diluent is dipentaerythritol hexaacrylate or ethoxylated bisphenol A diacrylate, or a mixture of several of them; Add 20 to 40 parts by weight of functional monomers in a light-proof environment, and continue stirring until the functional monomers are evenly mixed; In a light-proof environment, 2 to 7 parts by weight of the photoinitiator are slowly added dropwise at a preset dropping rate, and stirring is continued until the photoinitiator is evenly mixed.

13. A photovoltaic module, characterized in that: include: A busbar-free solar cell, a welding strip and an adhesive layer; the adhesive layer is used to fix the welding strip and the busbar-free solar cell, and the adhesive layer is formed by ultraviolet light curing of the glue described in any one of claims 1 to 11 or the glue prepared by the preparation method described in claim 12.

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