Butyl sealant for self-repairing photovoltaic module and preparation method of butyl sealant

Abstract

The invention relates to the technical field of photovoltaic packaging materials, and discloses a butyl sealant for a self-repairing photovoltaic module and a preparation method of the butyl sealant. The butyl sealant is prepared from the following substances in parts by weight: 40 to 60 parts of modified butyl rubber, 20 to 35 parts of inorganic filler, 5 to 15 parts of tackifying resin, 2 to 8 parts of plasticizer, 0.5 to 2 parts of anti-aging agent, 0.3 to 1.0 part of bifunctional crosslinking monomer, 0.08 to 0.25 part of composite catalyst, 2 to 5 parts of microcapsule type repairing agent and 3 to 10 parts of drying agent. According to the invention, through the dual-mechanism design of a'sulfydryl-amino-silicon oxygen bond 'dynamic network and the microcapsule type repairing agent, the self-repairing performance and the aging resistance are synchronously and remarkably improved, and the contradiction that'the self-repairing performance and the aging resistance of a traditional material are difficult to consider at the same time' is solved. Tests show that the 12h repair rate of the sealant for 3mm scratches at 50 DEG C is greater than or equal to 98%, the tensile strength retention rate is greater than or equal to 92% after the sealant is subjected to damp-heat aging at 85 DEG C / 85% RH for 1000 h, and the sealant is superior to existing similar products.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic encapsulation materials technology, specifically to a self-healing butyl sealant suitable for sensitive photovoltaic modules such as perovskite and heterojunction modules, and its preparation method. Background Technology

[0002] Butyl rubber, with its densely packed methyl groups on the side of its molecular chains, forms a unique structure that exhibits excellent airtightness and low water vapor permeability. Its air permeability is an order of magnitude lower than that of natural rubber, making it widely used for edge sealing of photovoltaic modules as the first line of defense against water. Especially in perovskite and heterojunction photovoltaic modules that are sensitive to moisture, butyl hot melt adhesives, with their solvent-free properties, anti-fogging performance, and thermoplastic characteristics, have become a core component of the sealing system.

[0003] However, current butyl sealants for photovoltaic applications still have several key problems: First, their adhesion to the glass interface is unsatisfactory. After aging under ultraviolet light, humidity, and high and low temperatures, they are prone to insufficient adhesive and delamination, leading to a significant decrease in adhesion and affecting the reliability of their moisture barrier function. Second, the material itself lacks self-healing capabilities. Damage, defects, or bubbles caused by operational errors during construction cannot be repaired independently, directly affecting the performance of the sealant and the product's pass rate. Third, in structurally complex areas such as module openings, the sealant is prone to uneven thickness and residual bubbles, which not only affect the appearance but may also cause insufficient insulation performance, creating safety hazards.

[0004] The aforementioned problems have become key factors restricting the long-term reliability and service life of photovoltaic modules. Therefore, developing a new type of butyl sealant with excellent interfacial adhesion, self-healing ability and construction adaptability has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a butyl sealant for photovoltaic modules that has strong adhesion, excellent aging resistance, and self-healing capabilities, while optimizing its preparation process to suit industrial production.

[0006] One objective of this invention is to provide a self-healing butyl sealant for photovoltaic modules, comprising the following components by weight: The mixture contains 40-60 parts modified butyl rubber, 20-35 parts inorganic filler, 5-15 parts tackifying resin, 2-8 parts plasticizer, 0.5-2 parts antioxidant, 0.3-1.0 parts bifunctional crosslinking monomer, 0.08-0.25 parts composite catalyst, 2-5 parts microcapsule repair agent, and 3-10 parts desiccant.

[0007] Furthermore, the raw materials for preparing the modified butyl rubber include halogenated butyl rubber, thiol-containing hydroxyl acid derivatives, amino-containing hydrogen silanes and alkoxy-containing hydrogen silanes. The molar ratio of the halogen group of the halogenated butyl rubber to the thiol group (-SH) of the hydroxyl acid derivative, the amino group (-NH2) in the amino-containing hydrogen silane, and the siloxane (-Si-O-) in the alkoxy-containing hydrogen silane is 1:(0.6-0.8):(0.2-0.4):(0.1-0.3).

[0008] The modified butyl rubber is the core of the performance of this invention. It is a product of halogenated butyl rubber modified through a synergistic dynamic system of "thiol-amino-siloxane bonds". This modification process involves reacting thiol-containing hydroxyl acrylate derivatives, amino-containing hydrosilanes, and alkoxy-containing hydrosilanes with halogenated butyl rubber to introduce a reversible dynamic covalent bond network (such as Si-O-Si, Si-OC) and hydrogen bond network (-NH2…O=C-) onto the rubber molecular chain. This dynamic network endows the matrix material with intrinsic self-healing capabilities while enhancing chemical bonding with substrates such as glass.

[0009] Furthermore, the thiol-containing hydroxyenoic acid derivative has the structural formula HS(CH2). k HO (CH2) m CH=CHCOOH, where k=1~3 and m=2~8.

[0010] Furthermore, the amino-containing hydrogen silane has the structural formula HSi(NH2)(OR²)2, where R² is a C1-C6 alkyl group.

[0011] Furthermore, the alkoxy-containing hydrogen silane is HSi(CH3)(OR) 3 )2,R 3 It is a C1 to C3 alkyl group.

[0012] Furthermore, the microcapsule-type repair agent is a spherical capsule with a urea-formaldehyde resin shell encapsulating a hydroxysiloxane core material, wherein the core material accounts for 60-70% of the capsule mass, and the capsule diameter is 5-10 μm.

[0013] When a material is damaged and cracks occur, the hydroxysiloxane core material released by the rupture of microcapsules can react with active groups (such as Si-H and -OH) in the matrix under the action of a catalyst, thereby achieving secondary filling and chemical repair of the cracks, forming an "active" repair mechanism for external damage, which works synergistically with the intrinsic repair mechanism.

[0014] Furthermore, the composite catalyst is a compound system of chloroplatinic acid and dibutyltin dilaurate, with a mass ratio of 1:0.5 to 1.5.

[0015] Furthermore, the bifunctional crosslinking monomer is selected from one or a mixture of two of mercaptoacrylic acid and mercaptomethacrylic acid. The bifunctional crosslinking monomer can participate in the formation of dynamic networks and serve as a connection point to enhance network stability.

[0016] Furthermore, the antioxidant is a composite system, which is composed of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester and tris(2,4-di-tert-butylphenyl) phosphite in a weight ratio of 1:0.8 to 1.2.

[0017] Furthermore, the inorganic filler is a mixture of fumed silica and talc, with a mass ratio of 1:2 to 4, and both have a mesh size greater than 500 mesh.

[0018] Furthermore, the tackifying resin is selected from one or two of terpene resin and hydrogenated C5 resin, and has a softening point of 80-120°C.

[0019] Furthermore, the plasticizer is polybutene with a number average molecular weight of 2000 to 5000.

[0020] Furthermore, the desiccant is a 3A-5A type molecular sieve with a particle size of 1-5 μm.

[0021] The second objective of this invention is to provide a method for preparing the aforementioned self-healing photovoltaic module butyl sealant, comprising the following steps: (1) Preparation of modified butyl rubber: Halogenated butyl rubber is dissolved in tetrahydrofuran, and a mercapto-containing hydroxyl olefin derivative and potassium carbonate are added. The reaction is carried out at 15-35℃ for 10-20h. A hydrogen-containing silane containing amino group, a hydrogen-containing silane containing alkoxy group and a composite catalyst are added, and the temperature is raised to 80-90℃ for 2-3h. 0.5-1.5 parts by weight of dibenzothiazole disulfide are added, and the temperature is maintained for 2-3h. The solvent is removed by vacuum distillation to obtain modified butyl rubber. (2) Melt blending: Add the modified butyl rubber obtained in step (1) to a kneader, tackifying resin and plasticizer, and knead at 110-130℃ for 15-25 minutes; (3) Functional component compounding: Cool the mixture obtained in step (2) to 80-100℃, add antioxidant, desiccant and inorganic filler, knead for 10-15 min; then cool to 60-70℃, add bifunctional crosslinking monomer and microcapsule repair agent, and stir with ultrasonic assistance for 15-20 min. (4) Vacuum degassing: The mixture obtained in step (3) is kneaded for 1 to 2 hours under a vacuum of 0.08 to 0.1 MPa and a temperature of 120 to 150°C to obtain the butyl sealant for self-healing photovoltaic modules.

[0022] Furthermore, in step (1), the amount of potassium carbonate added is 1.1 to 1.3 times the molar amount of the thiol-containing hydroxyenoic acid derivative.

[0023] Furthermore, in step (3), the power of the ultrasonic-assisted stirring is 300-500W, the frequency is 20-40kHz, and the stirring speed is 300-500r / min.

[0024] The self-healing butyl sealant for photovoltaic modules prepared in this invention exhibits a repair rate of ≥98% for a 3mm diameter scratch after 12 hours at 50℃. After 1000 hours of humid heat aging at 85℃ / 85%RH, its tensile strength retention rate is ≥92%, and its water vapor transmission rate is ≤0.2g / (m²). 2 •24h).

[0025] Compared with the prior art, the beneficial effects of the present invention are: I. Performance Synergistic Breakthrough: This invention achieves a simultaneous and significant improvement in self-healing performance and aging resistance through a dual mechanism design of a dynamic network of "thiol-amino-siloxane bonds" and a microcapsule-type repair agent, resolving the contradiction of traditional materials where "self-healing performance and aging resistance are difficult to balance." Testing shows that the sealant of this invention achieves a ≥98% repair rate for a 3mm scratch at 50℃ for 12 hours, and after 1000 hours of humid heat aging at 85℃ / 85%RH, the tensile strength retention rate is ≥92%, superior to existing similar products.

[0026] II. Excellent Interfacial Adhesion and Barrier Properties: This invention enhances the chemical affinity with glass surfaces by modifying the polar groups (such as -COOH, -NH2, Si-O-) in butyl rubber. Combined with a filler and desiccant system, this results in a sealant with high adhesive strength (≥1.7MPa) and extremely low water vapor permeability (≤0.2g / (m²)). 2 (24h) provides long-term protection for sensitive batteries such as perovskite batteries.

[0027] 3. Good process compatibility: The preparation method of the present invention does not require special equipment and has good compatibility with existing photovoltaic module packaging production lines (such as coating and lamination). The vacuum degassing process effectively solves the problem of residual bubbles in special parts.

[0028] IV. Long-term effectiveness and high economic efficiency: This invention endows the material with long-term service stability through dynamic cross-linking network, and forms a dual repair mechanism by combining the self-healing ability of microcapsules, which can significantly extend the service life of the sealing system of photovoltaic modules and reduce the operation and maintenance and replacement costs caused by sealing failure. Detailed Implementation

[0029] The present invention will be described below with reference to examples. These examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0030] Example 1 A self-healing butyl sealant for photovoltaic modules, comprising the following components by weight: Modified butyl rubber: 50 parts; The modified butyl rubber was prepared by reacting brominated butyl rubber, 7-hydroxy-9-mercapto-2-nonenoic acid, aminodiethoxysilane and methyltrimethoxysilane with a molar ratio of halogen: mercapto: amino:siloxane bond of 1:0.7:0.3:0.2. Inorganic filler: 28 parts (made by mixing fumed silica and talc in a mass ratio of 1:3, with a mesh size >800 mesh); Tackifying resin: 10 parts of terpene-styrene copolymer resin (TR-100); Plasticizer: Polybutene (Mn=3000) 5 parts; Composite antioxidant: 1 part (made by mixing β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester and tris(2,4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1). Bifunctional crosslinking monomer: 0.6 parts of mercaptoacrylic acid; Composite catalyst: 0.15 parts (made by mixing chloroplatinic acid and dibutyltin dilaurate in a mass ratio of 1:1). Desiccant: 6 parts of 3A molecular sieve; Microencapsulated repair agent: 3.5 parts (shell material is urea-formaldehyde resin, accounting for 35%, with a thickness of 1.5μm; core material is hydroxyl-terminated polydimethylsiloxane, accounting for 65%, with a particle size of 7μm). The preparation process of the microcapsule-type repair agent is as follows: 1. Raw material pretreatment: Take 65g of hydroxyl-terminated polydimethylsiloxane (core material), add 8mL of ethyl acetate to dilute, and obtain the diluted core material; Prepare urea-formaldehyde resin prepolymer (shell material precursor): Mix 35g of urea with 52.5g of 37% formaldehyde aqueous solution, adjust the pH to 8.5 with 10% NaOH solution, react at 55℃ for 1.5h, and cool to room temperature to obtain a transparent urea-formaldehyde resin prepolymer; 2. Emulsification and dispersion: Add 1.8g sodium dodecyl sulfate (emulsifier) ​​to 250mL of deionized water, stir to dissolve, then add the diluted core material, and shear and stir at 2200r / min for 22min to form a uniform oil droplet emulsion with a particle size of 7μm (ultrasonic aid: 400W, 30kHz, treatment for 10min). 3. In-situ polymerization: The emulsion was heated to 58°C, and the pH was adjusted to 2.5 with 10% hydrochloric acid. The above urea-formaldehyde resin prepolymer was slowly added dropwise. After the addition was completed, the reaction was kept at the temperature for 3.5 hours. During this period, the stirring speed was maintained at 500 r / min to ensure that the urea-formaldehyde resin was uniformly deposited on the surface of the oil droplets to form a 1.5 μm thick shell layer. 4. Post-processing: After the reaction is complete, wash the emulsion with deionized water until neutral, centrifuge (3000 r / min, 10 min), collect the microcapsules, and dry them at 45℃ and 0.08 MPa vacuum for 6 h to obtain the finished product.

[0031] The preparation method of the butyl sealant in this embodiment includes the following steps: (1) Preparation of modified butyl rubber: Brominated butyl rubber was dissolved in tetrahydrofuran, and 7-hydroxy-9-mercapto-2-nonenoic acid and 1.2 molar amounts of potassium carbonate were added. The mixture was reacted at 25°C for 15 h. Then, aminodiethoxysilane and a composite catalyst were added, and the temperature was raised to 85°C for 2.5 h (hydrosilylation reaction). Then, 1.0 part of dibenzothiazole disulfide was added, and the mixture was kept at this temperature for 2.5 h. The tetrahydrofuran was removed by vacuum distillation to obtain modified butyl rubber. (2) Melt blending: Add the above modified butyl rubber, terpene resin and polybutene to a kneader and knead at 120°C for 20 min; (3) Functional component compounding: Cool the material to 65°C, add composite antioxidant, desiccant and inorganic filler, knead for 12 min, continue to cool to 60°C, add mercaptoacrylic acid and microcapsule repair agent, turn on the ultrasonic (power 400W, frequency 30kHz) and keep mechanical stirring (speed 400r / min), disperse for 18 min; (4) Vacuum degassing: Vacuum up to 0.09MPa, heat up to 135℃, continue kneading for 1.5h, discharge the material, and cool to obtain the finished butyl sealant.

[0032] Example 2 This embodiment provides a self-healing butyl sealant for photovoltaic modules, which comprises the following components by weight: Modified butyl rubber: 45 parts (raw material composition is the same as in Example 1); Inorganic filler: 25 parts (fumed silica: talc = 1:2, mass ratio); Tackifying resin: 12 parts of hydrogenated C5 resin (softening point 110℃); Plasticizer: Polybutene (Mn=4000) 6 parts; Composite antioxidant: 1.2 parts (raw material components are the same as in Example 1); Bifunctional crosslinking monomer: 0.8 parts of mercaptomethacrylic acid; Composite catalyst: 0.2 parts (chloroplatinic acid: dibutyltin dilaurate = 1:1.2, mass ratio); Desiccant: 5 parts of 4A molecular sieve; Microcapsule-type repair agent: 5 parts (shell material is urea-formaldehyde resin, accounting for 30%, with a thickness of 1μm; core material is hydroxyl-terminated polydimethylsiloxane, accounting for 70%, with a particle size of 8μm); The preparation process of the microcapsule-type repair agent is as follows: 1. Raw material pretreatment: Take 70g of hydroxyl-terminated polydimethylsiloxane (core material), add 10mL of ethyl acetate to dilute, and obtain the diluted core material; Prepare urea-formaldehyde resin prepolymer (shell material precursor): Mix 30g of urea with 45g of 37% formaldehyde aqueous solution, adjust the pH to 8.5 with 10% NaOH solution, react at 55℃ for 1.5h, and cool to room temperature to obtain a transparent urea-formaldehyde resin prepolymer; 2. Emulsification and dispersion: Add 1.5g sodium dodecyl sulfate (emulsifier) ​​to 250mL of deionized water, stir to dissolve, then add the diluted core material, and stir at 1800r / min for 20min to form a uniform oil droplet emulsion with a particle size of 8μm (ultrasonic aid: 400W, 30kHz, treatment for 8min). 3. In-situ polymerization: Heat the emulsion to 58°C, adjust the pH to 2.5 with 10% hydrochloric acid, slowly add the above urea-formaldehyde resin prepolymer, keep the reaction at the temperature for 3 hours after the addition is complete, and maintain the stirring speed at 500 r / min during the process to ensure that the urea-formaldehyde resin is uniformly deposited on the surface of the oil droplets to form a 1 μm thick shell layer. 4. The post-processing steps are the same as in Example 1.

[0033] The butyl sealant in this embodiment is similar to that in Embodiment 1, except that: Step (1) The reaction temperature is 30℃ / 12h (first step) and 90℃ / 2h (second step), and 1.2 parts of dibenzothiazole disulfide are added.

[0034] Step (2) Kneading temperature is 125℃, time is 18min.

[0035] Step (3) The ultrasonic temperature is 70℃, the power is 500W, and the time is 15min.

[0036] Step (4) Vacuum degassing conditions are 0.08 MPa, 140 °C, 1 h.

[0037] Example 3 This embodiment provides a self-healing butyl sealant for photovoltaic modules, which comprises the following components by weight: Modified butyl rubber: 55 parts (raw material composition is the same as in Example 1); Inorganic filler: 30 parts (fumed silica: talc = 1:4, mass ratio); Tackifying resin: 8 parts of terpene resin (softening point 90℃); Plasticizer: Polybutene (Mn=2000) 4 parts; Composite antioxidant: 2 parts (a mixture of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester and tris(2,4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1.2). Bifunctional crosslinking monomer: 0.5 parts of mercaptomethacrylic acid; Composite catalyst: 0.1 parts (chloroplatinic acid: dibutyltin dilaurate = 1:0.8, mass ratio); Desiccant: 8 parts of 5A molecular sieve; Microcapsule-type repair agent: 2.5 parts (shell material is urea-formaldehyde resin, accounting for 40%, with a thickness of 2μm; core material is hydroxyl-terminated polydimethylsiloxane, accounting for 60%, with a particle size of 6μm); The preparation process is as follows: 1. Raw material pretreatment: Take 60g of hydroxyl-terminated polydimethylsiloxane (core material), add 6mL of ethyl acetate to dilute, and obtain diluted core material; Prepare urea-formaldehyde resin prepolymer (shell material precursor): Mix 40g of urea with 60g of 37% formaldehyde aqueous solution, adjust pH=8.5 with 10% NaOH solution, react at 55℃ for 1.5h, and cool to room temperature to obtain transparent urea-formaldehyde resin prepolymer; 2. Emulsification and dispersion: Add 2.0 g sodium dodecyl sulfate (emulsifier) ​​to 250 mL of deionized water, stir to dissolve, then add the diluted core material, and shear and stir at 2500 r / min for 25 min to form a uniform oil droplet emulsion with a particle size of 6 μm (ultrasonic aid: 400 W, 30 kHz, treatment for 12 min). 3. In-situ polymerization: Heat the emulsion to 58°C, adjust the pH to 2.5 with 10% hydrochloric acid, slowly add the above urea-formaldehyde resin prepolymer, keep the reaction at the temperature for 4 hours after the addition is completed, and maintain the stirring speed at 500 r / min during the process to ensure that the urea-formaldehyde resin is uniformly deposited on the surface of the oil droplets to form a 2 μm thick shell layer. 4. The post-processing steps are the same as in Example 1.

[0038] The butyl sealant in this embodiment is similar to that in Embodiment 1, except that: Step (1) The reaction temperature is 20℃ / 18h (first step) and 80℃ / 3h (second step), and 0.8 parts of dibenzothiazole disulfide are added.

[0039] Step (2) Kneading temperature is 115℃, time is 22min.

[0040] Step (3) The ultrasonic temperature is 60℃, the power is 300W, and the time is 20min.

[0041] Step (4) Vacuum degassing conditions are -0.1MPa, 130℃, 2h.

[0042] Comparative Example 1 The only difference between this comparative example and Example 1 is that: no modified butyl rubber is used, and an equal amount of unmodified brominated butyl rubber is used directly (i.e., no mercapto / amino reaction is performed), no composite catalyst or bifunctional crosslinking monomer is added, and the preparation step (1) is simplified to directly using the raw material rubber. Other components and subsequent preparation processes are exactly the same as in Example 1, and will not be repeated here.

[0043] Comparative Example 2 The only difference between this comparative example and Example 1 is that no microencapsulated repair agent is added. All other components and preparation processes are exactly the same as in Example 1 and will not be repeated here.

[0044] Comparative Example 3 This comparative example uses a traditional photovoltaic sealant formulation: 50 parts of ordinary butyl rubber 1765N (non-halogenated); 30 parts of calcium carbonate (inorganic filler); 10 parts of petroleum resin; 5 parts of paraffin oil (plasticizer); and 2641 parts of antioxidant (single-component antioxidant).

[0045] The preparation process of this comparative example is as follows: ordinary butyl rubber 1765N, petroleum resin, and paraffin oil are added to a kneader and kneaded at 120℃ for 20 min; the temperature is lowered to 80℃, antioxidant and inorganic filler are added, and stirring is continued for 15 min; ultrasonication (power 400W, frequency 30kHz) is turned on while maintaining mechanical stirring (speed 400r / min) for dispersion treatment for 18 min; vacuum is drawn to 0.09MPa, the temperature is raised to 135℃, and kneading treatment is continued for 1.5 h; the material is discharged and cooled to obtain the finished butyl sealant.

[0046] Performance testing The butyl sealants obtained in Examples 1-3 and Comparative Examples 1-3 were subjected to the following tests, and the results are summarized in Table 1.

[0047] 1. Self-healing performance: A standard sample of butyl sealant was prepared, and a linear scratch with a depth of 3mm penetrating the sealant layer was pre-applied to its surface. The sample was then placed in a constant temperature environment of 50℃ (±1℃) and relative humidity of 50% (±5%) for 12 hours. The degree of physical recovery of the scratched area was evaluated by the comprehensive self-healing rate, calculated as: Comprehensive self-healing rate = Appearance repair rate * 60% + Mechanical property repair rate (tensile shear strength) * 40%. This indicator directly reflects the sealant's ability to self-repair mechanical scratches within the photovoltaic module's operating temperature range (typical operating temperature of the module backsheet is 35~60℃), and is a key parameter ensuring the long-term sealing performance of the module.

[0048] (1) Test steps for appearance repair rate: ① Lay a standard sample of 50mm length × 25mm width × 2mm thickness flat on a glass slide. Make a 3mm long cut through the adhesive layer with a utility knife. Take a high-resolution image of the cut area under an optical microscope and mark the initial cut area S0. ②After 12 hours of static repair at 50℃: photograph the same area at the same focal length and mark the area S1 of the unclosed residual defect; ③ Calculate the appearance restoration rate: Appearance restoration rate = (S0-S1) / S0×100%.

[0049] (2) Test steps for mechanical repair rate: ① Test the tensile shear strength of a blank specimen (without scratches) and record it as the initial tensile shear strength σ0; ② Test the tensile shear strength of the specimen 0h after the scratch, and record it as the tensile shear strength σ2 caused by the scratch. ③ After the scratched tensile shear specimen was left to stand at 50℃ for 12 hours for repair, the tensile shear strength of the specimen was tested again. The tensile shear strength σ3 after repair was obtained. ④ Calculate the mechanical recovery rate: Mechanical recovery rate = (σ3-σ2) / (σ0-σ2)×100%.

[0050] 2. Tensile Shear Strength: Tested according to T / CPIA 0130—2025 "Technical Specification for Butyl Rubber for Photovoltaic Module Encapsulation" and GB / T7124 "Determination of Tensile Shear Strength of Adhesives (Rigid Material to Rigid Material)". Under standard test conditions, butyl rubber is bonded between two rigid materials to form a tensile shear specimen. A tensile testing machine is then used to apply shear force to the specimen, and the maximum shear force at failure is measured. The tensile shear strength is calculated in MPa.

[0051] 3. Perform performance tests according to GB / T3512 "Test Method for Thermal Aging of Vulcanized Rubber", evaluate the tensile strength before and after aging at 85℃ / 85%RH for 1000h, and calculate the aging performance retention rate.

[0052] 4. Water vapor transmission rate: According to T / CPIA 0130—2025 "Technical Specification for Butyl Rubber for Photovoltaic Module Encapsulation", the test method follows GB / T26253 "Determination of Water Vapor Transmission Rate of Plastic Films and Sheets - Infrared Detector Method". The test is conducted under standard test conditions, i.e., temperature (23±2)℃ and relative humidity (40~70)%. Butyl rubber samples of specified dimensions are prepared and placed in a water vapor transmission rate tester. The water vapor transmission rate is calculated by measuring the amount of water vapor passing through the sample over a certain period of time, with units of g / (m²). 2 24h).

[0053] Table 1. Performance comparison of butyl sealants in Examples 1-3 and Comparative Examples 1-3

[0054] Performance test results show: (1) Self-healing performance: Examples 1-3 exhibited an excellent repair rate of nearly 100%, which is attributed to the dual repair mechanism of "dynamic network + microcapsule". Comparative Example 1, lacking a dynamic cross-linking network, had extremely low repair ability, with a repair rate of only 15.3%, proving that dynamic bonds are the core of self-healing. Comparative Example 2, although possessing intrinsic repair ability (dynamic network), lacked active repair of large-size defects (microcapsule), resulting in a significant decrease in repair rate (82.6% vs 99.2%), with a decrease of approximately 16.6%, demonstrating the beneficial effect of microcapsules and indicating that microcapsules significantly improve the repair of large-size defects. Comparative Example 3 had no repair design.

[0055] (2) Aging resistance: The strength retention rate of Examples 1-3 after aging was not less than 92%, showing excellent durability; the aging resistance of Comparative Examples 1-3 was severely reduced due to the lack of an optimized anti-aging system and the protection of the dynamic network, with the retention rate all below 80%, verifying the synergistic anti-aging effect of the antioxidant and the dynamic system. The dynamic network of Comparative Example 2 provided good aging protection, proving the key role of the dynamic network in aging resistance.

[0056] (3) Water vapor barrier and adhesion performance: Due to the synergistic effect of the compound filler and molecular sieve, Examples 1-3 all exhibited good water vapor barrier and adhesion strength. In particular, Example 3, with its high filler content and molecular sieve dosage, resulted in better barrier performance (0.18 g / (m 2 (24h)). The traditional formula (Comparative Example 3) is only 0.52g / (m 2 (24h), the comparison shows that the material system of the present invention maintains excellent self-healing and aging resistance properties without sacrificing its core function as a sealant.

[0057] In summary, this invention, through ingenious molecular structure design and component compounding, successfully prepared a self-healing butyl sealant with excellent comprehensive performance, effectively solving the pain points of existing technologies, and is particularly suitable for new high-efficiency photovoltaic modules with extremely high reliability requirements.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A self-healing butyl sealant for photovoltaic modules, characterized in that, Includes the following substances in parts by weight: The mixture contains 40-60 parts modified butyl rubber, 20-35 parts inorganic filler, 5-15 parts tackifying resin, 2-8 parts plasticizer, 0.5-2 parts antioxidant, 0.3-1.0 parts bifunctional crosslinking monomer, 0.08-0.25 parts composite catalyst, 2-5 parts microcapsule repair agent, and 3-10 parts desiccant.

2. The butyl sealant for self-healing photovoltaic modules according to claim 1, characterized in that, The raw materials for preparing the modified butyl rubber include halogenated butyl rubber, thiol-containing hydroxyl acid derivatives, amino-containing hydrogen silanes, and alkoxy-containing hydrogen silanes. The molar ratio of the halogen group of the halogenated butyl rubber to the thiol group of the hydroxyl acid derivative, the amino group in the amino-containing hydrogen silane, and the siloxane in the alkoxy-containing hydrogen silane is 1:0.6-0.8:0.2-0.4:0.1-0.

3.

3. The butyl sealant for self-healing photovoltaic modules according to claim 2, characterized in that, The thiol-containing hydroxyenoic acid derivative has the structural formula HS(CH2). k HO (CH2) m CH=CHCOOH, where k=1~3, m=2~8; the amino-containing hydrogen silane has the structural formula HSi(NH2)(OR) 2 )2,R 2 It is a C1-C6 alkyl group; the alkoxy-containing hydrogen silane is HSi(CH3)(OR) 3 )2,R 3 It is a C1 to C3 alkyl group.

4. The butyl sealant for self-healing photovoltaic modules according to claim 1, characterized in that, The microcapsule-type repair agent is a spherical capsule with a urea-formaldehyde resin shell encapsulating a hydroxysiloxane core material. The core material accounts for 60-70% of the capsule's mass, and the capsule diameter is 5-10 μm.

5. The butyl sealant for self-healing photovoltaic modules according to claim 1, characterized in that, The composite catalyst is a mixture of chloroplatinic acid and dibutyltin dilaurate, with a mass ratio of 1:0.5 to 1.

5.

6. The butyl sealant for self-healing photovoltaic modules according to claim 1, characterized in that, The bifunctional crosslinking monomer is selected from one or a mixture of two of mercaptoacrylic acid and mercaptomethacrylic acid.

7. The butyl sealant for self-healing photovoltaic modules according to claim 1, characterized in that, The antioxidant is a composite system, which is composed of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester and tris(2,4-di-tert-butylphenyl) phosphite in a weight ratio of 1:0.8 to 1.

2.

8. The butyl sealant for self-healing photovoltaic modules according to claim 1, characterized in that, The inorganic filler is a mixture of fumed silica and talc, with a mass ratio of 1:2 to 4, and a mesh size greater than 500 mesh. The tackifying resin is selected from one or two of terpene resin and hydrogenated C5 resin, and the softening point is 80-120℃. The plasticizer is polybutene with a number average molecular weight of 2000-5000; The desiccant is a 3A-5A type molecular sieve with a particle size of 1-5 μm.

9. A method for preparing a butyl sealant for self-healing photovoltaic modules as described in any one of claims 1 to 8, characterized in that, Includes the following steps: (1) Preparation of modified butyl rubber: Halogenated butyl rubber is dissolved in tetrahydrofuran, and a mercapto-containing hydroxyl olefin derivative and potassium carbonate are added. The reaction is carried out at 15-35℃ for 10-20h. A hydrogen-containing silane containing amino group, a hydrogen-containing silane containing alkoxy group and a composite catalyst are added, and the temperature is raised to 80-90℃ for 2-3h. 0.5-1.5 parts by weight of dibenzothiazole disulfide are added, and the temperature is maintained for 2-3h. The solvent is removed by vacuum distillation to obtain modified butyl rubber. (2) Melt blending: Add the modified butyl rubber obtained in step (1) to a kneader, tackifying resin and plasticizer, and knead at 110-130℃ for 15-25 minutes; (3) Functional component compounding: Cool the mixture obtained in step (2) to 80-100℃, add antioxidant, desiccant and inorganic filler, knead for 10-15 min; then cool to 60-70℃, add bifunctional crosslinking monomer and microcapsule repair agent, and stir with ultrasonic assistance for 15-20 min. (4) Vacuum degassing: The mixture obtained in step (3) is kneaded for 1 to 2 hours under a vacuum of 0.08 to 0.1 MPa and a temperature of 120 to 150°C to obtain the butyl sealant for self-healing photovoltaic modules.

10. The method for preparing the butyl sealant for self-healing photovoltaic modules according to claim 9, characterized in that, In step (1), the amount of potassium carbonate added is 1.1 to 1.3 times the molar amount of the thiol-containing hydroxyenoic acid derivative; in step (3), the power of the ultrasonic-assisted stirring is 300 to 500 W, the frequency is 20 to 40 kHz, and the stirring speed is 300 to 500 r / min.

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