Packaging material for photovoltaic module and preparation method thereof

Abstract

The invention relates to the technical field of sealants, in particular to a packaging material for a photovoltaic module and a preparation method of the packaging material. The packaging material comprises the following components in percentage by weight: 10-20% of APAO, 10-20% of polyisobutene, 2-8% of butyl rubber, 0.1-2% of a silane coupling agent, 0.1-4% of an antioxidant and the balance of filler, and the water vapor transmittance of the packaging material at 38 DEG C and 90% RH is not higher than 0.02 g / (m < 2 >. 24h). The packaging material for the assembly provided by the invention has excellent weather resistance, air tightness and chemical stability, and can effectively prevent moisture, oxygen and the like from eroding the photovoltaic assembly, so that the service life of the assembly is prolonged, and the power generation efficiency of the assembly is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sealants, and in particular to a packaging material for a photovoltaic module and a preparation method thereof. Background Art

[0002] As the global energy crisis and environmental pollution intensify, solar energy has attracted much attention as a clean and renewable energy source. Among them, photovoltaic modules are the core of solar power generation systems, and their performance and quality directly affect power generation efficiency and service life. The selection of packaging materials is crucial. Although commonly used materials such as EVA (ethylene-vinyl acetate copolymer) and POE (ethylene-α-olefin copolymer elastomer) can meet basic needs, they are insufficient in terms of weather resistance, adhesion, and aging resistance. EVA is prone to yellowing and degradation, affecting light transmittance and power generation efficiency; POE has poor adhesion, affecting structural stability. The material also has poor aging resistance, affecting service life. Therefore, improving photovoltaic module packaging materials and improving performance and reliability are issues that need to be urgently addressed in the current photovoltaic manufacturing field, which is of great significance to promoting the development of solar energy.

[0003] Chinese invention patent CN106634653A relates to a photovoltaic module encapsulation film with a three-dimensional heat-conducting channel, a preparation method and a component. The invention discloses a photovoltaic module encapsulation film with a three-dimensional heat-conducting channel, comprising a polymer main resin, wherein the polymer main resin comprises one-dimensional carbon nanotubes and / or two-dimensional graphene, and a zero-dimensional heat-conducting particle filler, wherein the polymer main resin is EVA, POE, EPDM (ethylene propylene diene monomer rubber), which can timely and effectively transfer the heat generated by the solar module during the power generation process, reduce the operating temperature of the module, increase the power generation of the module, and reduce the power generation cost of the module. However, POE has poor adhesion, which affects the structural stability. Summary of the invention

[0004] The first aspect of the present invention provides a packaging material for photovoltaic modules, which comprises, by weight percentage, 10-20% of APAO (amorphous poly-α-olefin), 10-20% of polyisobutylene, 2-8% of butyl rubber, 0.1-2% of silane coupling agent, 0.1-4% of antioxidant, and the balance is made up of fillers, wherein the water vapor transmission rate (GB / T 26253) of the butyl rubber at 38°C and 90%RH is not higher than 0.02g / (m 2 ·24h).

[0005] The filler includes at least one of silicon dioxide, calcium carbonate, talc, barium sulfate, bentonite, mica, carbon black and molecular sieve.

[0006] Preferably, the filler comprises calcium carbonate, talcum powder and carbon black, and the weight ratio of the calcium carbonate, talcum powder and carbon black is 1:(0.4-0.6):(1-2).

[0007] The applicant has found through research that the filler includes calcium carbonate, talc and carbon black, and the weight ratio of calcium carbonate, talc and carbon black is limited to 1:(0.4-0.6):(1-2), which can improve the hardness and shear strength of the sealant. The calcium carbonate particles play a role of skeleton support in the adhesive, and the talc fills the tiny gaps in the adhesive to enhance the structural strength of the adhesive. Carbon black has a very high specific surface area and surface energy, and can form a strong interaction with APAO. At the same time, the carbon black particles can act as "cross-linking points" to connect calcium carbonate and talc, and together form a hard skeleton structure in the sealant.

[0008] Further research found that limiting the particle size of calcium carbonate to 60-100nm, talc including silane-modified talc and carbon black to 60-150nm can further increase the hardness of the sealant to 80 (Shore A), and the glass-to-glass shear strength is not less than 0.4MPa, making it applicable to the packaging of photovoltaic modules. The nanostructure of calcium carbonate and carbon black increases the specific surface area and activity of the filler, and is densely stacked inside the sealant, but at the same time, the nanostructure is easy to agglomerate, affecting its dispersibility in the sealant, while silane-modified talc lubricates the nanostructured talc and carbon black, and forms a certain physical cross-linking network with APAO by hydrogen bonding.

[0009] Preferably, the weight ratio of calcium carbonate, talc and carbon black is 1:(0.4-0.6):(1-1.4).

[0010] The softening point of the APAO is 150-175°C, the needle penetration at 25°C is 12-20 dmm, and the density is 0.8-0.94 g / cm 3 .

[0011] Preferably, the APAO has a softening point of 150-165°C, a needle penetration of 14-18 dmm at 25°C, and a density of 0.86-0.92 g / cm 3 .

[0012] APAO has excellent weather resistance and air tightness, but its adhesion to low surface energy and low surface substrates is relatively poor and its aging resistance is insufficient. The present application found that by compounding APAO, butyl rubber and polyisobutylene, and limiting the weight ratio of APAO, butyl rubber and polyisobutylene to (2-4): (1-1.5): 4, the aging resistance of the sealant can be effectively provided, and the water vapor transmission rate (GB / T26253) at 38°C and 90%RH is not higher than 0.02g / (m 2·24h). It meets the application of photovoltaic modules. It may be that the bonding performance and low crystallinity of APAO complement the stability and inertness of butyl rubber. At the same time, polyisobutylene plays the role of a tackifier, which can improve the wettability and permeability of the sealant to the adherend, thereby improving the bonding effect. On the other hand, van der Waals forces and hydrogen bonds will interact between the molecules of APAO, butyl rubber and polyisobutylene, effectively improving the density of the chain segments.

[0013] Generally speaking, the longer the polymer chain segment, the better its comprehensive performance, but at the same time, the dispersibility is subject to greater resistance. In particular, the present application involves the compounding of three polymer compounds and the use of up to four fillers, and its dispersibility is significantly limited. The applicant accidentally discovered that by limiting the Mooney viscosity of butyl rubber to 40-60, the viscosity-average molecular weight of polyisobutylene to 40000-100000, and the softening point of APAO to 150-175°C, the needle penetration at 25°C to 12-20dmm, and the density to 0.8-0.94g / cm 3 The melt index of the sealant can be controlled at 20-25g / 10min (130℃ / 10kg / 600s), while the water vapor transmission rate (GB / T 26253) can be as low as 0.01g / (m 2 ·24h), which may balance the chain length and dispersion performance of the polymer compounds and improve the structural stability of the system.

[0014] The weight ratio of the APAO, butyl rubber and polyisobutylene is (2-4):(1-1.5):4.

[0015] Preferably, the weight ratio of APAO, butyl rubber and polyisobutylene is (2-4):1:4.

[0016] The Mooney viscosity of the butyl rubber is 40-60.

[0017] Preferably, the Mooney viscosity of the butyl rubber is 45-55.

[0018] The viscosity average molecular weight of the polyisobutylene is 40,000-100,000.

[0019] Preferably, the viscosity average molecular weight of the polyisobutylene is 40,000-85,000.

[0020] Preferably, the silane coupling agent comprises a mixture of vinyl silane and an inert carrier.

[0021] The antioxidant includes antioxidant 1010 and antioxidant 168, and the weight ratio of the antioxidant 1010 to the antioxidant 168 is 1:(0.8-1.2).

[0022] The particle size of the calcium carbonate is 60-100 nm.

[0023] Preferably, the particle size of the calcium carbonate is 60-80 nm.

[0024] The talc includes silane-modified talc.

[0025] The particle size of the carbon black is 60-150 nm.

[0026] Preferably, the particle size of the carbon black is 80-130 nm.

[0027] The mesh number of the silicon dioxide is 1000-3000 mesh.

[0028] Preferably, the mesh size of the silicon dioxide is 1000-2000 mesh.

[0029] A second aspect of the present invention provides a method for preparing a packaging material for a photovoltaic module, comprising the following steps:

[0030] Step 1: stirring and mixing APAO, polyisobutylene, antioxidant, and calcium carbonate, talc and carbon black in fillers to obtain a mixture;

[0031] Step 2: Add the remaining filler and silane coupling agent to the mixture, stir evenly, and press to obtain the packaging material.

[0032] The stirring temperature in step 1 is 150-190° C. and the stirring time is 0.5-1.5 h. The stirring time in step 2 is 2-5 h.

[0033] Preferably, the stirring temperature in step 1 is 150-170° C. and the stirring time is 0.5-1.5 h, and the stirring time in step 2 is 2-4 h.

[0034] Beneficial Effects

[0035] 1. The filler includes calcium carbonate, talcum powder and carbon black, and the weight ratio of calcium carbonate, talcum powder and carbon black is limited to

[0036] 1: (0.4-0.6): (1-2), can improve the hardness and shear strength of the sealant.

[0037] 2. The particle size of calcium carbonate is limited to 60-100nm, the particle size of talc powder including silane-modified talc powder and the particle size of carbon black is limited to 60-150nm, which can further increase the hardness of the sealant to 80 (Shore A), and the glass-to-glass shear strength is not less than 0.4MPa.

[0038] 3. By compounding APAO, butyl rubber and polyisobutylene, and limiting the weight ratio of APAO, butyl rubber and polyisobutylene to (2-4): (1-1.5): 4, the aging resistance of the sealant can be effectively provided, and

[0039] The water vapor transmission rate (GB / T 26253) at 38°C and 90% RH is not higher than 0.02g / (m 2 ·24h).

[0040] Meet the application of photovoltaic components.

[0041] 4. By limiting the Mooney viscosity of butyl rubber to 40-60, the viscosity-average molecular weight of polyisobutylene to 40,000-100,000, the softening point of APAO to 150-175°C, the needle penetration at 25°C to 12-20 dmm, and the density to 0.8-0.94 g / cm 3 The melt index of the sealant can be controlled at 20-25g / 10min (130℃

[0042] / 10kg / 600s), and the water vapor transmission rate (GB / T 26253) is as low as 0.01g / (m 2 ·24h).

[0043] 5. By adopting a specific preparation process, the modified APAO can be evenly dispersed in the packaging material to form a stable structure, thereby improving the structural stability and power generation efficiency of the photovoltaic module. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the morphology of the sample in Example 1 before PCT aging.

[0045] Figure 2 This is the morphology of the sample in Example 1 after PCT aging for 500 hours.

[0046] Figure 3 This is the morphology of the sample in comparative example 1 after PCT aging for 500 hours. DETAILED DESCRIPTION

[0047] Examples 1-5, Comparative Examples 1-4

[0048] A packaging material for a photovoltaic module, the components of which are shown in Table 1 by weight percentage:

[0049] Table 1

[0050]

[0051]

[0052] In Examples 1-5 and Comparative Examples 1-2, the method for preparing the packaging material for the photovoltaic module comprises the following steps:

[0053] Step 1: The kneader is preheated to 170° C., APAO, methyl styrene resin, polyisobutylene, antioxidant, and calcium carbonate, talc and carbon black in the filler are mixed, and stirred at 170° C. for 1 hour to obtain a mixture;

[0054] Step 2: The remaining components were added to the mixture, stirred at 170° C. for 3 h, and laminated at 150° C. and 1.5 MPa to form a packaging material with a thickness of 1.5 mm.

[0055] In comparative example 3-4, the method for preparing the packaging material for the photovoltaic module comprises the following steps:

[0056] Step 1: The kneader is preheated to 170° C., APAO, butyl rubber, polyisobutylene, antioxidant, and calcium carbonate, talc and carbon black in the filler are mixed, and stirred at 170° C. for 1 hour to obtain a mixture;

[0057] Step 2: The remaining components were added to the mixture, stirred at 170° C. for 3 h, and laminated at 150° C. and 1.5 MPa to form a packaging material with a thickness of 1.5 mm.

[0058] Performance testing methods and data

[0059] The packaging materials prepared in the examples and comparative examples were subjected to performance tests, and the test data are listed in Table 2. The water vapor transmission rates of comparative examples 2-4 were too high, and the PCT aging test was not performed, which is marked with " / ".

[0060] PCT aging test: Add cobalt chloride reagent to the photovoltaic glass bonded with butyl adhesive, test it at a temperature of 105°C and a humidity of 100% for 500 hours, and observe the color change of the test paper; add cobalt chloride reagent to another photovoltaic glass bonded with butyl adhesive, test it at a temperature of 85°C and a humidity of 85% for 3000 hours, and observe the color change; if the color and surface morphology of the test paper do not change, it is qualified, otherwise it is unqualified.

[0061] Combination Figure 1 and Figure 2 It can be seen that the packaging material PCT prepared in Example 1 did not change in color before and after aging. Figure 3 It can be seen that the packaging material PCT prepared in Comparative Example 1 exhibits obvious blistering on its surface after aging.

[0062] Performance test data

[0063] Table 2

[0064]

[0065]

Claims

1. A packaging material for a photovoltaic module, characterized in that: The components include, by weight percentage: APAO 10-20%, polyisobutylene 10-20%, butyl rubber 2-8%, silane coupling agent 0.1-2%, antioxidant 0.1-4%, and filler to make up the balance. The water vapor transmission rate of the butyl rubber at 38°C and 90%RH is not higher than 0.02g / (m 2 ·24h).

2. The encapsulation material for photovoltaic modules according to claim 1, characterized in that: The filler includes at least one of silicon dioxide, calcium carbonate, talc, barium sulfate, bentonite, mica, carbon black and molecular sieve.

3. The packaging material for photovoltaic modules according to claim 2, characterized in that: The filler includes calcium carbonate, talcum powder and carbon black, and the weight ratio of calcium carbonate, talcum powder and carbon black is 1: (0.4-0.6): (1-2)。 4. The encapsulation material for photovoltaic modules according to claim 1, characterized in that: The weight ratio of the APAO, butyl rubber and polyisobutylene is (2-4):(1-1.5):

4.

5. The packaging material for photovoltaic modules according to claim 4, characterized in that: The Mooney viscosity of the butyl rubber is 40-60.

6. The packaging material for photovoltaic modules according to claim 4, characterized in that: The viscosity average molecular weight of the polyisobutylene is 40,000-100,000.

7. The packaging material for photovoltaic modules according to claim 1, characterized in that: The silane coupling agent comprises a mixture of vinyl silane and an inert carrier.

8. The packaging material for photovoltaic modules according to claim 3, characterized in that: The talc includes silane-modified talc.

9. A method for preparing a packaging material for a photovoltaic module according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: stirring and mixing APAO, polyisobutylene, butyl rubber, antioxidant, and calcium carbonate, talc and carbon black in fillers to obtain a mixture; Step 2: Add the remaining components to the mixture, stir evenly, and press to obtain the encapsulation material.

10. The preparation method according to claim 9, characterized in that: The stirring temperature in step 1 is 150-190° C. and the stirring time is 0.5-1.5 h. The stirring time in step 2 is 2-5 h.

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