An adhesive tape, its preparation method and use

Abstract

The present application relates to a kind of adhesive tape and its preparation method and application.The adhesive tape includes the insulating substrate layer, pressure-sensitive adhesive layer and release film layer which are stacked in sequence;The preparation raw material of the insulating substrate layer includes polyolefin substrate and elastomer.The adhesive tape of the present application solves the pain points such as insufficient insulation, easy aging and bonding force attenuation of traditional edge covering material by material modification and process optimization, and can be widely applied to various photovoltaic products such as crystalline silicon photovoltaic module, thin-film photovoltaic module, BIPV (photovoltaic building integrated) module, etc., providing key material support for the safe, stable and long-term operation of photovoltaic system, and has broad market application prospect and economic value.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic module protective materials technology, and in particular to an adhesive tape, its preparation method and application. Background Technology

[0002] As a core component of solar power generation systems, photovoltaic (PV) modules are exposed to the outdoor environment for extended periods, facing harsh conditions such as rain, ultraviolet radiation, high and low temperature cycling, and salt spray corrosion. Edge-sealing tape, a critical protective material for PV modules, is primarily used for sealing module edges and isolating conductive components. Its performance directly impacts the insulation safety, sealing reliability, and lifespan of the PV module. Against the backdrop of the rapid development of the PV industry, PV modules are constantly exposed to complex outdoor environments, facing multiple challenges including high temperatures, high humidity, ultraviolet radiation, and rain erosion. Among these challenges, the sealing and protection of the module edges is crucial for ensuring their long-term stable operation. If the edge seal fails, moisture can easily seep into the module, leading to cell corrosion and short circuits. This not only significantly reduces the module's power generation efficiency but may also shorten its lifespan (typically, PV modules are designed for a lifespan of 25-30 years; edge seal failure can reduce this lifespan by 5-10 years).

[0003] Traditional edge protection for photovoltaic modules often relies on ordinary insulating tape or silicone sealant. However, ordinary insulating tape suffers from poor water resistance and weak weather resistance, while silicone sealant is prone to complex application, long curing time, and interface cracking. Therefore, developing a photovoltaic insulating and water-blocking edge-sealing tape that combines excellent insulation performance, high water resistance, strong weather resistance, and convenient application has become an important requirement for addressing the pain points of photovoltaic module edge protection and promoting the high-quality development of the photovoltaic industry.

[0004] Existing photovoltaic edge-sealing tapes mostly use traditional polyolefins as the base material, which have problems such as insufficient insulation strength, poor heat resistance, and limited mechanical toughness. They are prone to aging and cracking during long-term outdoor use. At the same time, conventional acrylic pressure-sensitive adhesives are prone to yellowing and adhesion decay under ultraviolet radiation, causing the tape to peel off from the module substrate, lose its sealing and insulation effect, and thus cause safety hazards such as water ingress and short circuits in the module, affecting the stable operation of the photovoltaic system.

[0005] Therefore, developing a photovoltaic insulating and water-blocking edge-sealing tape with excellent insulation properties, aging resistance, strong adhesion, and adaptability to harsh environments has become an urgent need for the development of the photovoltaic industry. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide an adhesive tape, its preparation method, and its applications. Through material modification and process optimization, the adhesive tape of the present invention solves the pain points of traditional edge-sealing materials, such as insufficient insulation, easy aging, and weakened adhesion. It can be widely used in various photovoltaic products such as crystalline silicon photovoltaic modules, thin-film photovoltaic modules, and BIPV (Building Integrated Photovoltaics) modules, providing key material support for the safe, stable, and long-term operation of photovoltaic systems, and has broad market application prospects and economic value.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides an adhesive tape comprising an insulating substrate layer, a pressure-sensitive adhesive layer, and a release film layer stacked sequentially; the raw materials for preparing the insulating substrate layer include a polyolefin substrate and an elastomer.

[0008] In this invention, properties are adjusted through physical modification (such as elastomer blending) and chemical modification (such as grafting and crosslinking), which not only retains the original advantages of polyolefins such as lightweight and corrosion resistance, but also significantly improves insulation strength, thermal stability, and mechanical strength, effectively blocking current leakage and resisting extreme temperature shocks. The reactive compatibilization system of this invention solves the problem of interfacial incompatibility and achieves precise control of multiphase microstructure and a balance between rigidity and toughness.

[0009] Preferably, the polyolefin substrate comprises polyethylene and / or polypropylene.

[0010] Preferably, the polyethylene includes any one or a combination of at least two of high-density polyethylene, low-density polyethylene, or linear low-density polyethylene.

[0011] Preferably, the polypropylene includes any one or a combination of at least two of homopolymer polypropylene, propylene-ethylene block copolymer, and propylene-ethylene random copolymer.

[0012] The polypropylene of this invention has high isotacticity, controllable crystallinity, high rigidity, high modulus, heat resistance (100–130℃), and lightweight.

[0013] In this invention, the core reason for preferentially using high-density polyethylene (HDPE) and polypropylene (PP) as the polyolefin substrate is that both possess excellent electrical insulation properties, mechanical stability, chemical resistance, and processing compatibility. Furthermore, their insulation reliability can be further optimized through blending with elastomers and modification with additives, thus meeting the stringent requirements of equipment insulation layers. Preferably, the raw materials for preparing the pressure-sensitive adhesive layer include the following components by weight: 100 parts pressure-sensitive adhesive, 0.2-10 parts crosslinking agent, 0.5-5 parts light stabilizer, and 5-30 parts tackifying resin.

[0014] In this invention, a light stabilizer is added to the raw materials for preparing the pressure-sensitive adhesive layer. This effectively shields ultraviolet rays in the 280-400 nm wavelength band, inhibits the photo-oxidative degradation of acrylate molecular chains, and significantly improves the tape's yellowing performance. Simultaneously, a crosslinking agent is added to adjust the adhesive gel content to 60%-80%, balancing initial tack and holding power. This results in a peel strength ≥1.5 N / mm between the tape and substrates such as photovoltaic module frames, glass, and backsheets, achieving long-lasting and tight adhesion. Furthermore, the addition of a tackifying resin enhances the bonding strength of the pressure-sensitive adhesive layer. By using a light stabilizer to shield ultraviolet rays and a crosslinking agent to construct a three-dimensional crosslinked network, the two synergistically improve the adhesive layer's weather resistance, bonding strength, and durability, making it suitable for harsh outdoor / high-temperature / high-humidity environments.

[0015] The weight percentage of the crosslinking agent can be, for example, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, or 9 parts.

[0016] The weight percentage of the light stabilizer can be, for example, 1 part, 2 parts, 2.5 parts, 3 parts, or 4 parts.

[0017] The weight percentage of the tackifying resin can be, for example, 10 parts, 15 parts, 20 parts, 25 parts, or 28 parts.

[0018] Preferably, the raw materials for preparing the pressure-sensitive adhesive layer further include 0.5-10 parts of antioxidant, for example, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts or 9 parts, etc.

[0019] Preferably, the raw materials for preparing the pressure-sensitive adhesive layer further include 0.1-5 parts of coupling agent, such as 0.5 parts, 1 part, 2 parts, 3 parts or 4 parts, etc.

[0020] Preferably, the raw materials for preparing the pressure-sensitive adhesive layer further include 0-60 parts of organic solvent, such as 10 parts, 20 parts, 30 parts, 40 parts or 50 parts.

[0021] Preferably, the pressure-sensitive adhesive is a solvent-based pressure-sensitive adhesive.

[0022] Preferably, the solvent-based pressure-sensitive adhesive includes any one or a combination of at least two of polyurethane pressure-sensitive adhesives, silicone pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, natural rubber-based pressure-sensitive adhesives, and synthetic rubber-based pressure-sensitive adhesives.

[0023] Preferably, the crosslinking agent includes any one or a combination of at least two of epoxy crosslinking agents, isocyanate crosslinking agents, organic peroxides, or metal oxides.

[0024] In this invention, the isocyanate group (-NCO) has extremely strong nucleophilic reactivity and can undergo addition reactions with various groups containing active hydrogen. In the adhesives used with the insulating layer (such as polyurethane and acrylate adhesives), the isocyanate can crosslink with the hydroxyl groups in the resin, thereby improving the cohesive force of the adhesive layer and strengthening the interfacial adhesion between the adhesive layer and the polyolefin substrate, thus solving the problems of easy peeling and poor resistance to media in traditional adhesive layers.

[0025] Preferably, the antioxidant includes any one or a combination of at least two of aromatic amine antioxidants, hindered phenolic antioxidants, or auxiliary antioxidants.

[0026] Preferably, the light stabilizer includes an ultraviolet absorber and / or a hindered amine light stabilizer.

[0027] Preferably, the ultraviolet absorber includes any one or a combination of at least two of salicylates, benzophenones, benzimidazoles, substituted acrylonitriles, or triazines.

[0028] Preferably, the tackifying resin includes any one or a combination of at least two of rosin resin, modified rosin resin, terpene resin, or synthetic petroleum resin.

[0029] Preferably, the coupling agent comprises any one or a combination of at least two of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxyethoxy)silane, N-(2-aminoethyl-3-aminopropyl)trimethoxysilane, 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane, 3-(methacryloylchloro)propyltrimethoxysilane, or γ-methacryloyloxypropyltrimethoxysilane.

[0030] Preferably, the thickness of the pressure-sensitive adhesive layer is 0.05-0.15 mm, for example, it can be 0.06 mm, 0.08 mm, 0.1 mm, 0.12 mm or 0.14 mm, etc.

[0031] Preferably, the release film layer comprises a substrate film and an anti-stick coating layered sequentially.

[0032] Preferably, the raw materials for preparing the anti-stick coating include organosilicon and / or fluorinated release agent.

[0033] Preferably, the substrate film comprises a polyester film and / or a PP release film.

[0034] Preferably, the thickness of the substrate film is 0.025-0.15 mm, for example, it can be 0.05 mm, 0.07 mm, 0.09 mm, 0.12 mm or 0.14 mm, etc.

[0035] Preferably, the thickness of the release film layer is 0.025-0.1 mm, for example, it can be 0.03 mm, 0.05 mm, 0.06 mm, 0.07 mm or 0.09 mm, etc.

[0036] Preferably, the release force of the release film layer is 5-50 g / 25mm, for example, it can be 10 g / 25mm, 20 g / 25mm, 25 g / 25mm, 30 g / 25mm or 40 g / 25mm, etc.

[0037] Preferably, the thickness of the insulating substrate layer is 0.05-0.5 mm, for example, it can be 0.1 mm, 0.2 mm, 0.25 mm, 0.3 mm or 0.4 mm, etc.

[0038] Preferably, the surface tension of the insulating substrate layer is not less than 38 mN / m, for example, it can be 39 mN / m, 40 mN / m, 41 mN / m, 42 mN / m or 43 mN / m, etc.

[0039] Preferably, the mass of the elastomer is 10%-20% of the mass of the polyolefin substrate, for example, it can be 12%, 14%, 15%, 16% or 18%, etc.

[0040] Preferably, the raw materials for preparing the insulating substrate layer further include reinforcing fillers.

[0041] Preferably, the mass of the reinforcing filler is 5%-8% of the mass of the polyolefin substrate, for example, it can be 5.5%, 6%, 6.5%, 7% or 7.5%, etc.

[0042] Preferably, the reinforcing filler comprises nano-silica and / or talc.

[0043] Preferably, the raw materials for preparing the insulating substrate layer also include antioxidants.

[0044] Preferably, the antioxidant is 0.5%-1% of the mass of the polyolefin substrate, for example, it can be 0.6%, 0.7%, 0.75%, 0.8% or 0.9%.

[0045] Preferably, the antioxidant includes any one or a combination of at least two of hindered phenolic antioxidants, aromatic amine antioxidants, phosphite antioxidants, or thioester antioxidants.

[0046] In a second aspect, the present invention provides a method for preparing the adhesive tape as described in the first aspect, the method comprising the following steps: (1) A polyolefin substrate, an elastomer, optional reinforcing fillers and optional antioxidants are mixed, melt-blended in an extruder, cast into a film, and then stretched and shaped to obtain an insulating substrate layer; (2) Mix the raw materials for preparing the pressure-sensitive adhesive layer, stir evenly, coat it on the insulating substrate layer, and cure it at 80-120℃ (for example, it can be 85℃, 90℃, 95℃, 100℃, 105℃, 110℃ or 115℃, etc.) to obtain the pressure-sensitive adhesive layer; (3) A release film layer is laminated on the pressure-sensitive adhesive layer and then compacted by a pressure roller to obtain the tape.

[0047] Preferably, the coating method in step (2) is comma blade coating or micro-recessed coating process.

[0048] Preferably, after the pressure roller compacts the material in step (3), a post-processing step is also included, and the post-processing method includes slitting, inspection, and packaging.

[0049] Preferably, the method for preparing the adhesive tape includes the following steps: (1) A polyolefin substrate, an elastomer, optional reinforcing fillers and optional antioxidants are mixed and fed into a twin-screw extruder. The mixture is melt-blended at 160-190°C (e.g., 165°C, 170°C, 175°C, 180°C or 185°C, etc.). After being cast into a film through a T-die, the film is stretched and shaped by a biaxial stretching machine. The surface is then corona-treated to obtain the insulating substrate layer. (2) The raw materials for preparing the pressure-sensitive adhesive layer are mixed in a high-speed disperser and stirred at 800-1200 r / min (e.g., 900 r / min, 950 r / min, 1000 r / min, 1050 r / min or 1100 r / min, etc.) for 30-60 min (e.g., 35 min, 40 min, 45 min, 50 min or 55 min, etc.). The mixture is then uniformly coated onto the insulating substrate layer using a comma-shaped doctor blade or microgravure coating process, with a coating thickness of 0.05-0.15 mm (e.g., 0.06 mm, 0.08 mm, 0.1 mm, 0.12 mm or 0.14 mm, etc.). Subsequently, the mixture is placed in an oven at 80-120℃ (e.g., 85℃, 90℃, 95℃, 100℃, 105℃, 110℃ or 115℃, etc.) and dried for 10-20 min (e.g., 12 min, 14 min, 15 min, etc.). The pressure-sensitive adhesive layer is obtained by (e.g., 1 min, 16 min, or 18 min, etc.); (3) A release film layer is laminated on the pressure-sensitive adhesive layer, and the tape is obtained by pressing it with a pressure roller at 0.3-0.5 MPa (for example, it can be 0.35 MPa, 0.37 MPa, 0.4 MPa, 0.43 MPa or 0.45 MPa).

[0050] Thirdly, the present invention provides an application of the tape described in the first aspect in edge sealing or conductive component isolation and overall protection of photovoltaic modules.

[0051] Preferably, the photovoltaic module includes any one or a combination of at least two of crystalline silicon photovoltaic modules, thin-film photovoltaic modules, or BIPV modules.

[0052] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The insulating substrate layer is made of modified polyolefin material. Through composite modification technology, the insulation performance, heat resistance and mechanical strength are improved simultaneously, which solves the performance shortcomings of traditional polyolefin substrate. It can maintain a stable insulation effect for a long time in harsh environments and prevent current leakage and short circuit risks. (2) The pressure-sensitive adhesive layer introduces UV absorbers and crosslinking agents, which significantly improves the UV aging resistance of the tape, inhibits yellowing and adhesion decay, ensures long-term tight adhesion between the tape and the photovoltaic module substrate, and improves sealing reliability. (3) The product has a reasonable structural design and a three-layer composite structure that works together to provide multiple advantages such as insulation, water resistance, aging resistance, and easy construction. It can be adapted to photovoltaic power stations under different climatic conditions (high temperature and humidity, cold, coastal salt fog areas, etc.).

[0053] (4) The preparation process is mature and controllable, the raw materials are readily available, the production cost is moderate, and it is suitable for large-scale production. When applied to photovoltaic modules, it can significantly reduce the failure rate of the modules, extend the service life (design service life ≥ 25 years), and improve the overall reliability and economy of the photovoltaic system. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the structure of the tape provided in Embodiment 1 of the present invention; Among them, 1-insulating substrate layer; 2-pressure sensitive adhesive layer; 3-release film layer.

[0055] Figure 2 This is a schematic diagram illustrating the application of the tape of the present invention in photovoltaic modules. Detailed Implementation

[0056] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0057] The sources of some of the raw materials used in the following examples and comparative examples.

[0058] High-density polyethylene, purchased from Daqing Petrochemical, grade 5200B; POE elastomer, purchased from Dow Chemical, grade 8480; Nano-silica, purchased from Evonik AEROSIL 200; Acrylic emulsion, purchased from BADF RS-9988; The isocyanate crosslinking agent was hexamethylene diisocyanate trimer, purchased from BASF Germany, brand name Basonat HI 100; The tackifying resin was C5 petroleum resin, purchased from Eastman, USA, with the brand name Piccotac 1095; Silicone-coated polyester release film, purchased from Keyue New Materials, grade KY25TD03; Homopolymer polypropylene (PPH) was purchased from Sinopec Yanshan Petrochemical, with the grade PPH T30S; EPDM elastomer, purchased from Dow Chemical Company, USA, brand name Nordel IP 4770P; Solvent-based acrylic pressure-sensitive adhesive, purchased from Henkel, Germany, brand name Loctite LIOFOL LA2740; PP release film, purchased from SKC Korea, brand name SKC SPN; Low-density polyethylene (LDPE), purchased from Sinopec Qilu Petrochemical, grade LDPE 2102TN00; Linear low-density polyethylene (LLDPE), purchased from ExxonMobil, grade LLDPE1002YB.

[0059] Example 1 This embodiment provides an adhesive tape and its preparation method. A schematic diagram of the adhesive tape is shown below. Figure 1 As shown, it includes an insulating substrate layer 1, a pressure-sensitive adhesive layer 2, and a release film layer 3 stacked in sequence.

[0060] Based on a mass percentage of 100% for the raw materials used in preparing the insulating substrate layer, the raw materials include 80% high-density polyethylene, 15% POE elastomer, 4.5% nano-silica, and 0.5% 4010NA (IPPD): N-isopropyl-N'-phenyl-p-phenylenediamine. The thickness of the insulating substrate layer is 0.2 mm.

[0061] Based on a mass percentage of 100% for the raw materials used in the preparation of the pressure-sensitive adhesive layer, the raw materials include 90% acrylate emulsion, 3% UV-327 ultraviolet absorber, 2% isocyanate crosslinking agent, and 5% tackifying resin. The thickness of the pressure-sensitive adhesive layer is 0.1 mm.

[0062] The release film is a silicone-coated polyester film with a thickness of 0.03 mm.

[0063] The method for preparing the adhesive tape includes the following steps: (1) Substrate preparation: The raw materials for preparing the insulating substrate layer are mixed and fed into a twin-screw extruder, melt-blended at 170°C, cast into a film, biaxially stretched and shaped, and corona treated to obtain the insulating substrate layer; (2) Mix the raw materials for preparing the pressure-sensitive adhesive layer, stir at 1000 r / min for 40 min, apply it to the surface of the insulating substrate layer with a comma scraper, and dry it in an oven at 100°C for 15 min to obtain the pressure-sensitive adhesive layer. (3) A silicone-coated polyester film is laminated onto the pressure-sensitive adhesive layer, compacted, and cut into 50mm wide finished products to obtain the tape.

[0064] Example 2 This embodiment provides an adhesive tape and its preparation method. The adhesive tape comprises an insulating substrate layer, a pressure-sensitive adhesive layer, and a release film layer stacked sequentially.

[0065] Based on the mass percentage of the raw materials used to prepare the insulating substrate layer being 100%, the raw materials used to prepare the insulating substrate layer include 80% homopolymer polypropylene, 13.2% EPDM elastomer, 6% talc, and 0.8% antioxidant, and the thickness of the insulating substrate layer is 0.15 mm. Based on a mass percentage of 100% for the raw materials used in preparing the pressure-sensitive adhesive layer, the raw materials include 88% solvent-based acrylic adhesive, 4% UV-531 ultraviolet absorber, 3% isocyanate crosslinking agent, and 5% tackifying resin. The thickness of the pressure-sensitive adhesive layer is 0.08 mm. The release film layer is a PP release film with a thickness of 0.04 mm.

[0066] The preparation method of the tape is the same as that in Example 1.

[0067] Example 3 This embodiment provides an adhesive tape and its preparation method. Specifically, the adhesive tape includes a modified insulating substrate layer 1, a pressure-sensitive adhesive layer 2, and a release film layer 3 stacked sequentially.

[0068] Based on a mass percentage of 100% for the raw materials used in preparing the insulating substrate layer, the raw materials include 80% high-density polyethylene, 15% POE elastomer, 4.5% nano-silica, and 0.5% N-isopropyl-N'-phenyl-p-phenylenediamine, and the thickness of the insulating substrate layer is 0.2 mm.

[0069] Based on a mass percentage of 100% for the raw materials used in the preparation of the pressure-sensitive adhesive layer, the raw materials include 90% acrylate emulsion, 3% UV-327 ultraviolet absorber, 2% hexamethylene diisocyanate trimer, and 5% tackifying resin. The thickness of the pressure-sensitive adhesive layer is 0.1 mm.

[0070] The release film is a silicone-coated polyester film with a thickness of 0.03 mm.

[0071] The method for preparing the adhesive tape includes the following steps: (1) Substrate preparation: The raw materials for preparing the insulating substrate layer are mixed and fed into a twin-screw extruder, melt-blended at 170°C, cast into a film, biaxially stretched and shaped, and corona treated to obtain the insulating substrate layer; Prepare a 1.0 wt% aqueous solution of silane coupling agent KH-550 (aminopropyltriethoxysilane) in ethanol, and adjust the pH to 4-5; immerse the insulating substrate layer in the solution for 2 min, remove it and air dry at room temperature, and then bake it at 90℃ for 10 min to obtain the modified insulating substrate layer.

[0072] (2) Mix the raw materials for preparing the pressure-sensitive adhesive layer, stir at 1000 r / min for 40 min, apply it to the surface of the insulating substrate layer with a comma scraper, and dry it in an oven at 100°C for 15 min to obtain the pressure-sensitive adhesive layer. (3) A silicone-coated polyester film is laminated onto the pressure-sensitive adhesive layer, compacted, and cut into 50mm wide finished products to obtain the tape.

[0073] Example 4 This embodiment provides an adhesive tape and its preparation method, which differs from Embodiment 1 only in that high-density polyethylene is replaced with the same mass of low-density polyethylene.

[0074] Example 5 This embodiment provides an adhesive tape and its preparation method, which differs from Embodiment 1 only in that high-density polyethylene is replaced with the same mass of linear low-density polyethylene.

[0075] Example 6 This embodiment provides an adhesive tape and its preparation method. The only difference from Embodiment 1 is that, based on the mass percentage of the raw materials for preparing the pressure-sensitive adhesive layer being 100%, the raw materials for preparing the pressure-sensitive adhesive layer include 90% acrylate emulsion, 5% isocyanate crosslinking agent, and 5% tackifying resin.

[0076] Example 7 This embodiment provides an adhesive tape and its preparation method. The only difference from Embodiment 1 is that, based on the mass percentage of the raw materials for preparing the pressure-sensitive adhesive layer being 100%, the raw materials for preparing the pressure-sensitive adhesive layer include 90% acrylic emulsion, 5% UV-327 ultraviolet absorber, and 5% tackifying resin.

[0077] Comparative Example 1 This comparative example provides an adhesive tape and its preparation method. The only difference from Example 1 is that, based on the mass percentage of the raw materials for preparing the insulating substrate layer being 100%, the raw materials for preparing the insulating substrate layer include 95% high-density polyethylene, 24.5% nano-silica, and 0.5% antioxidant.

[0078] Test methods Insulation performance test (1) Breakdown voltage test (refer to GB / T 1408.1-2022 "Electrical strength test methods for insulating materials - Part 1: Power frequency test") Test sample: Cut a 10mm×100mm sample from the finished tape, remove the release film, and attach the pressure-sensitive adhesive layer to a clean aluminum plate (ensure no bubbles or wrinkles) as the lower electrode; the upper electrode is a 25mm diameter circular copper electrode (with rounded edges to avoid electric field concentration).

[0079] Test conditions: ambient temperature 23℃±2℃, relative humidity 50%±5%; using the "step-by-step voltage increase method", the initial voltage is 5kV, the voltage is increased by 2kV at each step, and the dwell time at each step is 1min, until the sample breaks down, and the voltage value at the moment of breakdown is recorded; repeat the test 5 times, and take the average value as the final breakdown voltage (unit: kV / mm, which needs to be converted to "voltage / substrate thickness").

[0080] (2) Insulation resistance test (refer to GB / T 1410-2006 Test method for volume resistivity and surface resistivity of solid insulating materials) Test sample: Cut a 50 mm × 50 mm sample, remove the release film, and then attach it to a polished stainless steel plate (surface resistivity < 10). 4 Ω), using a three-electrode system (main electrode diameter 20 mm, protective electrode inner diameter 25 mm, outer electrode outer diameter 50 mm), the electrode is in close contact with the sample surface (applying 0.1 MPa pressure).

[0081] Test conditions: ambient temperature 23℃±2℃, relative humidity 50%±5%; apply 500V DC voltage, let stand for 1 minute and then read the insulation resistance value. Calculate the volume resistivity (unit: Ω·cm) according to the formula "volume resistivity ρv=R×S / d" (R is insulation resistance, S is the area of ​​the main electrode, and d is the thickness of the substrate).

[0082] Weather resistance test (1) Ultraviolet aging test (refer to GB / T 16422.3-2022 "Laboratory Light Source Exposure Test Methods for Plastics - Part 3: Fluorescent Ultraviolet Lamps") Test sample: Cut a 50mm×150mm sample, retain half of the release film (as a blank control), and after removing the release film from the other half, attach it to the aluminum alloy frame commonly used in photovoltaic modules (surface pretreatment: wipe with alcohol to remove oil).

[0083] Test conditions: UVA-340 lamp tube (simulating outdoor ultraviolet light, wavelength 280-400nm, irradiance 0.71W / (m²)) was used. 2 •nm)); Execute “Cyclic Mode”: 8h UV irradiation (temperature 60℃±3℃, no condensation) + 4h dark condensation (temperature 50℃±3℃, relative humidity 95%±5%), for a total of 1000h of testing.

[0084] Test items: ① Yellowing index: The L*, a*, and b* values ​​of the samples before and after aging were measured using a colorimeter (CIE LAB system), and the yellowing index ΔE was calculated as √[(ΔL*)]. 2 +(Δa*) 2 +(Δb*) 2 ]; (2) High and low temperature cycling test (refer to IEC 61215-2:2021 "Design qualification and type approval of terrestrial crystalline silicon photovoltaic modules - Part 2: Test procedures") Test sample: The tape was applied to a photovoltaic module simulation piece (a composite structure of glass + encapsulating film + backsheet) to make a 100mm×100mm test piece with complete edge sealing.

[0085] Test conditions: Perform a "-40℃~120℃ cycle" in a high and low temperature chamber: ① Low temperature stage: -40℃±2℃, hold for 2 hours; ② Heating stage: rise to 120℃±2℃ at a rate of 10℃ / min; ③ High temperature stage: 120℃±2℃, hold for 2 hours; ④ Cooling stage: drop to -40℃ at a rate of 10℃ / min, complete 1 cycle, and accumulate 50 cycles.

[0086] Judgment criteria: After cycling, disassemble the test piece and observe that the tape is free from cracks and peeling, and that the bonding surface is free from bubbles and moisture penetration; retest the insulation resistance to be ≥10 ohms.12 Ω·cm, peel strength ≥1.2N / mm (initial value ≥1.5N / mm).

[0087] Adhesion performance test (1) Peel strength test (refer to GB / T 2792-2014 "Adhesives 180° peel strength test method") Test sample: Cut a 25mm×200mm tape sample, remove the release film, and attach the pressure-sensitive adhesive layer to the commonly used substrates of photovoltaic modules (aluminum alloy frame, tempered glass). Roll the sample back and forth 3 times with a 2kg roller at a speed of 300mm / min. Test after placing the sample at room temperature for 24 hours.

[0088] Test conditions: tensile testing machine speed 300mm / min ± 10mm / min, test angle 180°, record the maximum force value during the peeling process, and take the average value of 5 tests (unit: N / mm).

[0089] Water resistance performance test (1) Water vapor transmission rate test (refer to GB / T 1037-2021 "Determination of water vapor transmission rate of plastic films and sheets - cup method") Test sample: Cut a 70mm diameter sample (remove the release film), seal it in the test chamber of the permeation cup (the test chamber is filled with anhydrous calcium chloride, relative humidity 0%), and place the permeation cup in an environment with a temperature of 38℃±1℃ and a relative humidity of 90%±2%.

[0090] Test procedure: Initially weigh the total mass of the permeation cup (m0), then weigh it once every 24 hours (m). n ), continuously tested for 7 days, according to the formula "Water vapor transmission rate WVT=(m n The transmittance (unit: g / (m²)) is calculated using the formula: -m0) / (A×t)" where A is the effective area of ​​the sample and t is the testing time. 2 ·24h).

[0091] Tensile strength: Tested using a universal testing machine, in accordance with GB / T 528–2009 or GB / T 1040.1–2018.

[0092] The test results are shown in Table 1.

[0093] Table 1 The test results show that: (1) As can be seen from Examples 1-7, the present invention adjusts the properties through physical modification (such as elastomer blending) and chemical modification (such as grafting and crosslinking), which not only retains the original advantages of polyolefins such as lightweight and corrosion resistance, but also significantly improves insulation strength, heat resistance and mechanical strength, effectively blocking current leakage and resisting extreme temperature shocks. A schematic diagram of the application of the tape of the present invention in photovoltaic modules is shown below. Figure 2 As shown, 1 is the front panel glass / back panel, 2 is the encapsulation film, 3 is the battery cell, 4 is the rear panel glass / back panel, 5 is the module frame layer, 6 is the release film layer, 7 is the insulating substrate layer, and 8 is the pressure-sensitive adhesive layer.

[0094] (2) By comparing Example 1 with Examples 4-5, it can be seen that the present invention improves the performance of the tape by further selecting high-density polyethylene as the polyolefin substrate.

[0095] A comparison of Examples 1 and 6-7 shows that the present invention improves the peel strength and yellowing resistance of the tape by further introducing ultraviolet absorbers and isocyanate crosslinking agents into the pressure-sensitive adhesive layer.

[0096] (3) By comparing Example 1 with Comparative Example 1, it can be seen that the present invention introduces an elastomer into the insulating substrate layer, so that the resulting tape is corrosion resistant, lightweight, has high insulation strength, good thermal stability and high mechanical strength.

[0097] In summary, this invention solves the problems of insufficient insulation, easy aging, and weakened adhesion of traditional edge-binding materials through material modification and process optimization.

[0098] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A type of adhesive tape, characterized in that, The tape comprises an insulating substrate layer, a pressure-sensitive adhesive layer, and a release film layer stacked sequentially. The raw materials for preparing the insulating substrate layer include polyolefin substrate and elastomer.

2. The tape according to claim 1, characterized in that, The polyolefin substrate includes polyethylene and / or polypropylene; Preferably, the polyethylene includes any one or a combination of at least two of high-density polyethylene, low-density polyethylene, or linear low-density polyethylene; Preferably, the polypropylene includes any one or a combination of at least two of homopolymer polypropylene, propylene-ethylene block copolymer, and propylene-ethylene random copolymer.

3. The tape according to claim 1 or 2, characterized in that, The raw materials for preparing the pressure-sensitive adhesive layer include the following components by weight: 100 parts pressure-sensitive adhesive, 0.2-10 parts crosslinking agent, 0.5-5 parts light stabilizer, and 5-30 parts tackifying resin; Preferably, the raw materials for preparing the pressure-sensitive adhesive layer further include 0.5-10 parts of antioxidant; Preferably, the raw materials for preparing the pressure-sensitive adhesive layer further include 0.1-5 parts of a coupling agent; Preferably, the raw materials for preparing the pressure-sensitive adhesive layer further include 0-60 parts of organic solvent.

4. The tape according to claim 3, characterized in that, The pressure-sensitive adhesive is a solvent-based pressure-sensitive adhesive; Preferably, the solvent-based pressure-sensitive adhesive includes any one or a combination of at least two of polyurethane pressure-sensitive adhesives, silicone pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, natural rubber-based pressure-sensitive adhesives, and synthetic rubber-based pressure-sensitive adhesives; Preferably, the crosslinking agent includes any one or a combination of at least two of epoxy crosslinking agents, isocyanate crosslinking agents, organic peroxides, or metal oxides; Preferably, the antioxidant includes any one or a combination of at least two of aromatic amine antioxidants, hindered phenolic antioxidants, or auxiliary antioxidants; Preferably, the light stabilizer comprises an ultraviolet absorber and / or a hindered amine light stabilizer; Preferably, the ultraviolet absorber includes any one or a combination of at least two of salicylates, benzophenones, benzimidazoles, substituted acrylonitriles, or triazines; Preferably, the tackifying resin includes any one or a combination of at least two of rosin resin, modified rosin resin, terpene resin, or synthetic petroleum resin; Preferably, the coupling agent comprises any one or a combination of at least two of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxyethoxy)silane, N-(2-aminoethyl-3-aminopropyl)trimethoxysilane, 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane, 3-(methacryloylchloro)propyltrimethoxysilane, or γ-methacryloyloxypropyltrimethoxysilane.

5. The tape according to any one of claims 1-4, characterized in that, The thickness of the pressure-sensitive adhesive layer is 0.05-0.15 mm.

6. The tape according to any one of claims 1-5, characterized in that, The release film layer comprises a substrate film and an anti-stick coating layered sequentially; Preferably, the raw materials for preparing the anti-stick coating include organosilicon and / or fluorinated release agent; Preferably, the substrate film comprises a polyester film and / or a PP release film; Preferably, the thickness of the substrate film is 0.025-0.15 mm; Preferably, the thickness of the release film layer is 0.025-0.1 mm.

7. The tape according to any one of claims 1-6, characterized in that, The thickness of the insulating substrate layer is 0.05-0.5 mm.

8. The tape according to any one of claims 1-7, characterized in that, The mass of the elastomer is 10%-20% of the mass of the polyolefin substrate; Preferably, the raw materials for preparing the insulating substrate layer further include reinforcing fillers; Preferably, the mass of the reinforcing filler is 5%-8% of the mass of the polyolefin substrate; Preferably, the reinforcing filler comprises nano-silica and / or talc; Preferably, the raw materials for preparing the insulating substrate layer further include antioxidants; Preferably, the antioxidant is 0.5%-1% of the mass of the polyolefin substrate; Preferably, the antioxidant includes any one or a combination of at least two of hindered phenolic antioxidants, aromatic amine antioxidants, phosphite antioxidants, or thioester antioxidants.

9. A method for preparing an adhesive tape as described in any one of claims 1-8, characterized in that, The preparation method includes the following steps: (1) A polyolefin substrate, an elastomer, optional reinforcing fillers and optional antioxidants are mixed, melt-blended in an extruder, cast into a film, and then stretched and shaped to obtain an insulating substrate layer; (2) Mix the raw materials for preparing the pressure-sensitive adhesive layer, stir evenly, coat it onto the insulating substrate layer, and cure it at 80-120℃ to obtain the pressure-sensitive adhesive layer; (3) A release film layer is laminated on the pressure-sensitive adhesive layer and then compacted by a pressure roller to obtain the tape.

10. The application of the tape as described in any one of claims 1-8 in edge sealing or conductive component isolation and overall protection of photovoltaic modules; Preferably, the photovoltaic module includes any one or a combination of at least two of crystalline silicon photovoltaic modules, thin-film photovoltaic modules, or BIPV modules.

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