Epoxy resin crystal drop glue for solar panel sealing glue and preparation method of epoxy resin crystal drop glue

Abstract

The invention discloses epoxy resin crystal glue for sealing a solar panel and a preparation method of the epoxy resin crystal glue, and belongs to the field of solar panel crystal glue. Sequentially adding the dried EVA resin, the POE toughening agent and the activated anti-PID filler into an internal mixer; the initial temperature is set to be 140 DEG C, and low-speed stirring (30rpm) is carried out for 5 minutes to realize matrix infiltration; sequentially adding the dried EVA resin, the POE toughening agent and the activated anti-PID filler into an internal mixer; the initial temperature is set to be 140 DEG C, low-speed stirring (30 rpm) is conducted for 5 minutes to achieve matrix infiltration, the materials are heated to 160 DEG C, and HALS770 (0.5%) is directly put into a reaction kettle. The HALS770 captures free radicals generated by photooxidation, the antioxidant 1010 (main antioxidant) captures alkoxy free radicals, and the antioxidant 168 (auxiliary antioxidant) decomposes peroxides to form a three-dimensional protective network, so that the yellowing and mechanical property attenuation of the material are obviously delayed, and the risk of interfacial stress concentration is reduced.

Description

Technical Field

[0001] The invention belongs to the field of crystal glue production, and particularly relates to an epoxy resin crystal glue for solar panel sealing and a preparation method thereof. Background Art

[0002] When solar panels are exposed to the outdoors for a long time, ultraviolet rays (especially the UVA band) will cause the molecular chains of the encapsulation material to break, resulting in yellowing, embrittlement and reduced light transmittance of the colloid, which directly affects the photoelectric conversion efficiency. For example, EVA film without added antioxidants is easily decomposed under ultraviolet rays to produce acetic acid, accelerating material corrosion and performance degradation.

[0003] Long-term exposure to ultraviolet rays can cause the molecular chains on the surface of the glue to break, resulting in a decrease in light transmittance (for example, after aging, the light transmittance may drop to below 80%), affecting the side view clarity and aesthetics. At the same time, transparent glue tends to turn yellow and become brittle under ultraviolet rays, further affecting light transmittance. It may even cause delamination or damage to the battery cells due to shrinkage, and even water vapor penetration may corrode the battery cells and shorten the life of the component. Summary of the Invention

[0004] The purpose of the present invention is to provide an epoxy resin crystal glue for solar panel sealing and a preparation method thereof, so as to solve the problems in the prior art that the drying operation is relatively cumbersome and difficult to collect and preserve.

[0005] An epoxy resin crystal glue for solar panel sealing, composed of the following raw materials in percentage by weight:

[0006] EVA (VA content 28%) 85%

[0007] UV-327 (benzotriazole) 1.2%

[0008] HALS770 (hindered amine) 0.5%

[0009] Dicumyl peroxide (DCP) 1.0%

[0010] KH-550 silane coupling agent 0.4%

[0011] Antioxidant 1010 0.3%

[0012] Antioxidant 0.3%

[0013] POE toughening agent 8%

[0014] Anti-PID functional filler 3%

[0015] Defoaming agent 0.05% to 1%;

[0016] Preferably, the resin crystal glue has a light transmittance of ≥89% and a yellowing index ΔYI ≤1.5 after QUV 3000h.

[0017] Preferably, the hindered amine includes one of the following groups: light stabilizer 622, light stabilizer 770, light stabilizer 944, light stabilizer 783, light stabilizer 791, light stabilizer 3853, light stabilizer 292, and light stabilizer 123.

[0018] Preferably, the resin crystal glue PID resistance test temperature is tested at 85°C / 85% RH for 96 hours, and the power attenuation rate is ≤3%.

[0019] Preferably, the anti-PID functional filler includes the following: POE film filler, EVA film modified filler (high barrier type, composite modified), and conductive particle doped filler.

[0020] Preferably, the antioxidant includes Finox L-20, V-900 (applicable to polyester / polyurethane) and V-990 (applicable to epoxy / polyurethane), and phosphite antioxidant Y-205 / Y-211.

[0021] Preferably, the defoaming agent is selected from one of 066N, A530, defoaming agent 6800, 141, KV-352, 354, or a mixture of two thereof.

[0022] Preferably, the defoamer is polyacrylate or modified silicone

[0023] The advantages of the present invention are:

[0024] 1. The present invention forms a chemical bond by reacting the amino group (-NH2) of the silane coupling agent with the hydroxyl group (-OH) on the surface of the filler, thereby improving the compatibility of the filler with the matrix (such as EPDM or POE) and reducing the risk of interfacial stress concentration. The improved filler has improved dispersibility, blocks the potential-induced charge migration path, and improves the anti-PID performance by ≥30%. When KH-550 and hydroxy silicone oil are used to modify epoxy resin together, a denser cross-linked network can be formed, further improving the corrosion resistance and mechanical strength of the coating.

[0025] 2. HALS770 captures free radicals generated by photooxidation, antioxidant 1010 (primary antioxidant) captures alkoxy free radicals, and antioxidant 168 (secondary antioxidant) decomposes peroxides to form a three-dimensional protective network, significantly delaying the yellowing of the material and the degradation of mechanical properties. The total addition of HALS and antioxidants is 0.8%, which meets the needs of most outdoor scenes and avoids the migration of additives or cost waste caused by excessive addition.

[0026] 3. The addition amounts of KH-550 (1%) and HALS (0.8%) have been optimized to avoid curing abnormalities (such as surface stickiness) caused by excessive addition while ensuring that the functional additives fully participate in the reaction. The viscosity of the epoxy resin and filler is adjusted by diluents and dispersants to ensure construction fluidity and reduce residual bubbles. The addition amounts of KH-550 and HALS are both less than 2%, reducing raw material costs while ensuring performance. The reasonable selection of fillers (such as silica powder and alumina) further optimizes the cost structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of materials for four groups of embodiments of the present invention.

[0028] Figure 2 Schematic diagram of two sets of composite embodiments of the present invention.

[0029] Figure 3 Schematic diagram of the material comparison effect in the present invention.

[0030] Figure 4 Schematic diagram of the process optimization effect in the present invention

[0031] Figure 5 Schematic diagram of the cost of different types of formulations in the present invention. DETAILED DESCRIPTION

[0032] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0033] like Figures 1 to 5 As shown, an epoxy resin crystal glue for solar panel sealing and a preparation method thereof;

[0034] Example 1: 30ml of glue A + 1.5ml of diluent + 10ml of glue B. First, mix glue A and glue B according to the mass ratio (the common ratio is 3:1). Use the reverse mixing method: add fillers and plasticizers first, and finally add UV-A and HALS to reduce the agglomeration of additives.

[0035] Example 2: Basic Formulation: Mix epoxy resin A and curing agent B in a 3:1 ratio (precisely weighed). Additive Ratio: UV-A absorber (e.g., benzotriazole): Recommended addition: 0.5%-2% of the total adhesive weight. HALS light stabilizer (e.g., Chiguard 5050): Recommended addition: 0.3%-1.5% of the total adhesive weight.

[0036] Preheat the raw materials: Preheat glue A and glue B to 40-50°C to reduce viscosity and improve mixing uniformity. 45 UV-A and HALS must be pre-dispersed and dissolved in a small amount of glue A (to avoid direct addition to glue B to initiate a reaction). 18

[0037] Mix the modified adhesive solution; combine the UV-A and HALS-containing adhesive A solution with the remaining adhesive A and stir at low speed until completely dispersed. Add adhesive B and stir uniformly in a single direction for 5-10 minutes until the adhesive solution is transparent and free of stringiness. Transfer the mixed adhesive solution to a vacuum degassing machine and degas at -0.08MPa for 5-8 minutes.

[0038] Example 3:

[0039] Filler pretreatment method: prepare the silane coupling agent into a 0.3%-2% aqueous solution or ethanol solution, spray it on the surface of the filler (such as glass fiber, silicon powder), stir at high speed for 10-30 minutes, ensure uniform coating, and then dry at 120℃ for 2 hours; stir the modified A glue and B glue in one direction at a uniform speed for 5-10 minutes until transparent and without drawing, and transfer them to a vacuum degassing machine (-0.08MPa, 5-8 minutes) to remove bubbles.

[0040] Spray the mold with a release agent (such as silicone oil), preheat the substrate at 60°C for 30 minutes to remove moisture, inject the glue into the mold in batches, and adjust the curing conditions to room temperature for 24 hours or gradient heating (50°C×2h→80°C×1h) to enhance the interface bonding strength.

[0041] Disadvantages of this embodiment: The hydrolyzed silane solution must be used within 1 hour, otherwise the continued polycondensation reaction will reduce the coupling activity, limiting its application in large-scale continuous production scenarios. When the silane coupling agent on the filler surface is not completely dry (residual moisture > 100 ppm), mixing with the polar resin can easily induce interfacial microphase separation, reducing the mechanical properties of the composite material.

[0042] Example 4: Pour glue B and then add glue A to reduce bubbles, and then add KH-550 silane coupling agent: the addition amount is 1% of the total glue amount, and it needs to be stirred and mixed with the resin simultaneously;

[0043] HALS (light stabilizer): The addition amount is 0.8% of the total amount of rubber. It is recommended to add it slowly in the middle of stirring to improve the dispersion uniformity;

[0044] Slowly add HALS (0.8%) and stir until there are no obvious particles or color separation (about 2-3 minutes);

[0045] After mixing, let it stand for 10-15 minutes to reduce internal bubbles by natural defoaming. If there are too many bubbles, place the container in a 40-50℃ water bath to accelerate defoaming (to avoid premature curing due to high temperature).

[0046] Pour the glue into the mold slowly to avoid introducing bubbles too quickly. Curing at room temperature takes 24-48 hours, while high temperature curing (60-80°C) can be shortened to 4-6 hours (after adding HALS, the stirring speed needs to be accelerated (800-1000 rpm), and dispersant needs to be added if necessary)

[0047] The disadvantage of this embodiment is that HALS may compete with other additives (such as hindered phenol antioxidants and thioester thermal stabilizers) for free radicals, reducing the synergistic effect, and the addition order needs to be optimized through premixing experiments; sulfur-containing compounds (such as organotin thiols) will undergo redox reactions with HALS, resulting in the simultaneous degradation of the functions of both, requiring the addition of an isolation phase in the formulation or the use of a non-reactive stabilizer.

[0048] The first four embodiments primarily provide UV protection: adding 0.3%-0.8% of polymeric HALS (such as Tianjing HS-944) to polypropylene improves UV aging resistance by 40% compared to conventional HALS. Furthermore, the silanol groups generated by hydrolysis of KH-550 form covalent bonds with the surface hydroxyl groups of inorganic fillers (such as nano-alumina). The hydrogen functional groups react with the epoxy groups of the epoxy resin to form a strong chemical bond at the organic-inorganic interface, significantly enhancing interfacial bonding strength.

[0049] Example 5: The EVA base material (80-92%) is treated in a blast drying oven at 80°C for 4 hours, and the moisture content needs to be ≤200ppm8; the POE toughening agent (8%) needs to be vacuum dried (60°C×2h) to avoid bubbles during mixing.

[0050] Subsequently, the functional filler was activated, and the anti-PID functional filler (3%) was pre-mixed with KH-550 silane coupling agent (0.4%): the filler was dried at 120°C and then dispersed with KH-550 in a high-speed mixer at a mass ratio of 10:1 (speed 1500 rpm × 15 min;

[0051] In an internal mixer, add dried EVA resin, POE toughening agent, and activated anti-PID filler in sequence; set the initial temperature to 140°C, stir at a low speed (30 rpm) for 5 minutes to achieve matrix infiltration, heat the materials to 160°C, and directly add HALS770 (0.5%) into the reactor, evenly disperse it with the resin, and mix for 3 minutes;

[0052] After maintaining the temperature at 160°C, antioxidants 1010 and 168 (0.6%) were added and mixed. The heat of the materials was then reduced to 120°C. DCP (1.0%) was added to the reactor. The mixture was transferred to a twin-screw extruder and cast through a T-die to form a film with a thickness of 0.5±0.05mm. The film was then immediately passed through a calendering roller (temperature 80°C, pressure 0.5MPa) to eliminate surface defects. (The anti-PID filler treated with KH-550 should be added at the beginning of the mixing process to ensure full contact with the resin. HALS770 and UV absorber (if added) should be added in stages to prevent additive agglomeration.)

[0053] The advantages of this processing method are: the POE molecular chain contains unsaturated double bonds, the vacuum environment isolates oxygen, and low-temperature drying at 60°C can avoid the degradation of mechanical properties caused by thermal oxidative aging, and avoid the deterioration of compatibility between POE and polar materials (such as EVA) due to moisture in subsequent processing. Compared with traditional forced air drying, it shortens the time by 50%, reduces energy consumption while maintaining the elastomeric properties of the toughening agent.

[0054] Example 6: EPDM rubber formulation processing steps (including key points for component coordination control)

[0055] 1. Raw material pretreatment

[0056] EPDM rubber pretreatment: Place EPDM rubber (12%) in a 60°C oven and dry for 2 hours to remove 25% of surface adsorbed moisture; if recycled rubber is used, additional plasticizing is required (open mill roller temperature ≤ 50°C, thin pass 3 times).

[0057] Subsequently, the functional filler is activated, and nano-silica (5%) and a silane coupling agent (such as KH-550) are premixed at a mass ratio of 10:1 and processed in a high-speed mixer (1500 rpm×10 min) to enhance dispersibility.

[0058] In an internal mixer, add EPDM rubber, nanosilica mixture, and paraffin oil (if the formula contains a plasticizer) in this order; set the initial temperature to 80°C and mix at a low speed (20 rpm) for 8-10 minutes to ensure uniform dispersion of the filler. Adding 1%-3% HALS to the epoxy resin system can delay the risk of UV-induced embrittlement.

[0059] When HALS and UV absorber UV-A are mixed at a ratio of 1:2, the anti-yellowing efficiency of GPPS resin is increased by 35%;

[0060] When 0.5% HALS (such as HS-770) and 0.3% UV absorber are added, the transmittance of the EVA film decreases by less than 5% after 3000 hours of QUV aging.

[0061] The material was heated to 100°C, and the composite antioxidant (BHT+DLTP.0.6%) was mixed for 3 minutes. Then, the temperature was maintained at 100°C, and UV-531 (0.8% in proportion) was added into the material. Finally, the material was cooled to 70°C, and a sulfur cross-linking system (1.2% in proportion) was added, and the material was mixed for 1 minute.

[0062] The mixed rubber is transferred to the open mixing mill and supplemented with activator (5 parts zinc oxide + 1 part stearic acid. If not pre-mixed, the sheet is thinned out and the thickness is controlled to 2±0.2mm. After molding, the product is secondary vulcanized in a 140℃ oven for 1 hour to eliminate residual stress. (This process balances the processability, anti-aging properties and mechanical strength of EPDM rubber through gradient temperature control and activator optimization, and can adapt to the needs of scenarios such as photovoltaic sealing strips and outdoor rubber parts).

[0063] The application of recycled rubber may bring the following disadvantages: molecular chain damage: the molecular chain of recycled rubber is broken due to multiple processing, and plasticization will further reduce the mechanical properties; increased energy consumption: the plasticization time needs to be extended to improve plasticity, resulting in increased energy consumption and production costs; poor vulcanization stability: the vulcanization curve of recycled rubber fluctuates greatly, which may affect the uniformity and durability of the final product.

[0064] It is understood from common technical knowledge that the present invention may be implemented by other embodiments that do not depart from its spirit or essential features. Therefore, the embodiments disclosed above are, in all respects, merely illustrative and not exclusive. All modifications within the scope of the present invention or equivalent to the scope of the present invention are intended to be encompassed by the present invention.

Claims

1. An epoxy resin crystal glue for sealing solar panels, characterized by: It is composed of the following raw materials in percentage by weight: EVA (VA content 28%) 85% UV-327 (benzotriazole) 1.2% HALS770 (hindered amine) 0.5% Dicumyl peroxide (DCP) 1.0% KH-550 silane coupling agent 0.4% Antioxidant 10100.3% Antioxidant 0.3% POE toughening agent 8% Anti-PID functional filler 3% Defoaming agent 0.05%~1%.

2. The epoxy resin crystal glue for sealing solar panels according to claim 1, characterized in that: The resin crystal glue has a light transmittance of ≥89% and a yellowing index ΔYI ≤1.5 after QUV 3000h.

3. The epoxy resin crystal glue for sealing solar panels according to claim 1, characterized in that: The hindered amine includes one of the following groups: light stabilizer 622, light stabilizer 770, light stabilizer 944, light stabilizer 783, light stabilizer 791, light stabilizer 3853, light stabilizer 292, and light stabilizer 123.

4. The epoxy resin crystal glue for sealing solar panels according to claim 1, characterized in that: The resin crystal glue PID resistance test temperature is tested at 85°C / 85% RH for 96 hours, and the power attenuation rate is ≤3%.

5. The epoxy resin crystal glue for sealing solar panels according to claim 1, characterized in that: The anti-PID functional fillers include the following: POE film fillers, EVA film modified fillers, and conductive particle doped fillers.

6. The epoxy resin crystal glue for sealing solar panels according to claim 1, characterized in that: The antioxidants include FinoxL-20, V-900 (applicable to polyester / polyurethane) and V-990 (applicable to epoxy / polyurethane), and phosphite antioxidants Y-205 / Y-211.

7. The epoxy resin crystal glue for sealing solar panels according to claim 1, characterized in that: The defoaming agent is selected from one of 066N, A530, defoaming agent 6800, 141, KV-352, 354, or a mixture of two thereof.

8. The epoxy resin crystal glue for sealing solar panels according to claim 7, characterized in that: The defoaming agent is polyacrylate or modified silicone.

9. The method for preparing the epoxy resin crystal glue according to any one of claims 1 to 8, characterized in that: Raw material pretreatment Resin base material drying: EVA base material (80-92%) is treated in a forced air drying oven at 80℃ for 4 hours. The moisture content must be ≤200ppm8; POE toughening agent (8%) needs to be vacuum dried (60℃×2h) to avoid bubbles during mixing; Functional filler activation: Anti-PID functional filler (3%) and KH-550 silane coupling agent (0.4%) were pre-mixed: after the filler was dried at 120°C, it was dispersed with KH-550 in a high-speed mixer at a mass ratio of 10:1; Mixing and dispersion process The main ingredients were premixed; dried EVA resin, POE toughening agent, and activated anti-PID filler were added sequentially in an internal mixer; the initial temperature was set to 140°C and stirred at a low speed for 5 minutes to achieve matrix impregnation; dried EVA resin, POE toughening agent, and activated anti-PID filler were added sequentially in an internal mixer; the initial temperature was set to 140°C and stirred at a low speed for 5 minutes to achieve matrix impregnation, the materials were heated to 160°C, HALS770 (0.5%) was directly added to the reactor, uniformly dispersed with the resin, mixed for 3 minutes, and the mixture was transferred to a twin-screw extruder; Glue treatment Use glue dispensing equipment to evenly cover the surface of the solar cell with epoxy resin. The thickness of the glue layer is controlled at 0.5-1.2mm to ensure that the electrode contacts are completely covered. Place the glue-coated battery assembly into a vacuum box and apply a pressure of -0.08MPa to -0.1MPa to eliminate the micro gap between the glue layer and the battery cell. Step curing The first stage of curing: constant temperature at 120℃ for 30 minutes to form a preliminary cross-linking network with a cross-linking degree of 60-70%; Second stage curing: heat to 150-160℃ and hold for 60-90 minutes to allow the residual active groups to fully react and increase the crosslinking degree to ≥95%; Post-processing Remove excess glue from the edges and verify the anti-yellowing performance of the encapsulation layer through UV aging tests.

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