A uv-debonding flexible glass acid-resistant thinning film and a preparation method thereof

Abstract

The application belongs to the technical field of pressure-sensitive adhesive materials, and particularly relates to a UV adhesion-reducing flexible glass acid-resistant thinning film and a preparation method thereof. The acid-resistant thinning film comprises, from top to bottom, a substrate layer, a buffer layer, a pressure-sensitive adhesive layer and a release film layer. The pressure-sensitive adhesive layer is prepared from the following raw materials in parts by mass: 100-105 parts of an acrylate copolymer glue solution, 5-8 parts of modified two-dimensional hexagonal boron nitride nanosheets, 0.5-2 parts of a crosslinking agent and 2-4 parts of a photoinitiator. The film has excellent acid resistance, no residual glue and no damage after film tearing, and is suitable for the chemical etching thinning protection of flexible glass.

Description

Technical Field

[0001] This invention belongs to the field of pressure-sensitive adhesive materials technology, specifically relating to a UV-resistant, acid-resistant, and anti-adhesive flexible glass film and its preparation method. Background Technology

[0002] With the accelerated commercialization of next-generation electronic devices such as foldable screens and flexible displays, ultra-thin flexible glass (UTG), with its high light transmittance, flatness, and bendability, has become a core supporting material for flexible display cover plates. In the preparation and application of flexible glass, chemical etching for thinning (such as etching using a hydrofluoric acid system) is a key process for controlling its thickness; simultaneously, protection of the non-processed surfaces is required in subsequent manufacturing processes. These processes place stringent comprehensive performance requirements on the protective film, including resistance to acid etching, high adhesion, and low-damage peeling.

[0003] UV-resistant anti-adhesion protective films are used in semiconductor wafer cutting and packaging because their adhesion can be controlled and adjusted through ultraviolet light irradiation. However, existing technologies still have many shortcomings.

[0004] For example, Chinese patent application CN110256983A discloses a UV anti-adhesion protective film, which includes a substrate layer, a UV anti-adhesion layer, and a release film layer. The UV anti-adhesion layer is composed of polyacrylate, multifunctional monomers, crosslinking agents, and photopolymerization initiators. It reduces adhesion through UV irradiation-induced polymerization and curing, enabling smooth chip pickup. However, this UV anti-adhesion protective film is only suitable for semiconductor wafer dicing. It has poor resistance to hydrofluoric acid and mixed strong acids, easily swells, bleeds, and de-adheses in etching solutions, and cannot release stress, making it highly susceptible to damage to ultra-thin glass.

[0005] Chinese patent application CN1940096A discloses an acid and alkali resistant UV-resistant protective film, comprising a substrate layer, a UV-resistant layer, and a release film layer. The UV-resistant layer is made from an adhesive composition containing epoxy-modified acrylate pressure-sensitive adhesive, polyurethane acrylate, fluorinated acrylate, and modified clay. However, the UV-resistant adhesive composition in this application is complex, and phase separation easily occurs between the fluorinated acrylate and the epoxy-modified acrylate, resulting in a shortened adhesive life. Furthermore, the fluorinated acrylate is expensive, hindering large-scale industrial production. Summary of the Invention

[0006] Existing technologies lack a UV anti-adhesion protective film that possesses strong resistance to acid etching, especially to hydrofluoric acid mixed acid systems, leaves no adhesive residue, has a simple processing method, and is cost-effective. Therefore, this invention provides a UV anti-adhesion flexible glass acid-resistant film and its preparation method.

[0007] To achieve the objectives of this invention, the following technical solution is adopted: In a first aspect, the present invention provides a UV-resistant, non-adhesive, flexible glass acid-resistant film, which comprises, from top to bottom, a substrate layer, a buffer layer, a pressure-sensitive adhesive layer, and a release film layer. The pressure-sensitive adhesive layer is prepared from the following raw materials in parts by weight: 100-105 parts of acrylate copolymer adhesive, 5-8 parts of modified two-dimensional hexagonal boron nitride nanosheets, 0.5-2 parts of crosslinking agent, and 2-4 parts of photoinitiator; The acrylate copolymer solution is prepared by copolymerizing isoborneol acrylate, dodecyl methacrylate, isooctyl acrylate, acrylic acid and hydroxyethyl acrylate, and then grafting it with ethyl isocyanate acrylate.

[0008] By adopting the above technical solution, the acrylate copolymer adhesive solution, after copolymerization and grafting reaction, has both good adhesion and acid resistance. The modified two-dimensional hexagonal boron nitride nanosheets can further improve the acid resistance and high temperature resistance of the pressure-sensitive adhesive layer. The crosslinking agent and photoinitiator work together to achieve a rapid decrease in adhesion after UV irradiation, which meets the requirements of stable fixation during etching and low-stress, residue-free peeling after etching. It is suitable for the thinning process of ultra-thin flexible glass and effectively solves the problems of insufficient acid resistance, easy glass peeling, and residue of existing materials.

[0009] Furthermore, the preparation method of the acrylate copolymer adhesive includes the following steps: (A) Mix isobornyl acrylate, dodecyl methacrylate, isooctyl acrylate, acrylic acid and hydroxyethyl acrylate with a portion of the initiator to obtain a mixture; under nitrogen protection, heat the reaction vessel containing ethyl acetate to 75-80°C, and add the mixture dropwise to the reaction vessel; after the dropwise addition is complete, heat to 80-85°C and react for 1-1.5 hours; mix the remaining initiator with ethyl acetate at a mass ratio of 1:(7-10), add the mixture to the reaction vessel in two portions, and continue the reaction for 2-3 hours. (B) Lower the temperature to 40~45℃, stop the nitrogen gas supply, and replace it with dry air. Add dibutyltin dilaurate and hydroquinone monomethyl ether and mix well. Under light-protected conditions, add ethyl isocyanate acrylate dropwise and react for 4~6 hours. Adjust the solid content to 40%~45% with ethyl acetate, filter, and the filtrate is the acrylate copolymer solution.

[0010] By adopting the above technical solution, the copolymerization reaction of isobornyl acrylate, dodecyl methacrylate, isooctyl acrylate, acrylic acid, and hydroxyethyl acrylate can first achieve synergistic complementarity of the properties of each monomer. Isobornyl acrylate gives the adhesive excellent acid resistance and rigidity, while dodecyl methacrylate improves the flexibility and viscosity of the adhesive, so that the copolymer product has good viscosity, flexibility, and acid resistance. Secondly, the subsequent grafting reaction with ethyl isocyanate can introduce photoresponsive groups into the copolymer molecular chain, providing core support for the UV-induced viscosity reduction performance of the pressure-sensitive adhesive layer.

[0011] Further, the mass ratio of isoborneol acrylate, dodecyl methacrylate, isooctyl acrylate, acrylic acid, hydroxyethyl acrylate, ethyl isocyanate acrylate, initiator, dibutyltin dilaurate, and hydroquinone monomethyl ether is (25~35):(25~30):(10~15):(2~5):(10~15):(5~10):(0.2~0.5):(0.05~0.1):(0.01~0.05).

[0012] By adopting the above technical solution and optimizing the ratio of each raw material, the micro-phase separation of the rigid ring and the flexible chain segment is optimized. This ensures that the adhesive has sufficient lubrication to relax stress and prevent edge lifting and acid leakage, as well as a sufficiently dense network to block acid molecules, thus ensuring that the acrylate copolymer has good adhesion, flexibility and acid resistance.

[0013] Further, in step (A), the amount of ethyl acetate pre-loaded into the reactor is 100% to 150% of the total mass of isobornyl acrylate, dodecyl methacrylate, isooctyl acrylate, acrylic acid, hydroxyethyl acrylate, ethyl isocyanate, initiator, dibutyltin dilaurate and hydroquinone monomethyl ether.

[0014] By adopting the above technical solution, it is ensured that all reaction raw materials are fully dissolved and evenly dispersed, providing a stable reaction environment for the copolymerization reaction and avoiding uneven reaction and unstable product performance due to excessively high raw material concentration.

[0015] Furthermore, the preparation method of the modified two-dimensional hexagonal boron nitride nanosheets includes the following steps: (1) Mix 10 parts by mass of hexagonal boron nitride with 100-110 parts by mass of NaOH aqueous solution with a concentration of 5 mol / L, sonicate for 1.5-2 h, keep warm at 155-165℃ for 20-24 h, cool, wash, and dry to obtain hydroxylated two-dimensional hexagonal boron nitride nanosheets. (2) Mix 160-170 parts by weight of anhydrous ethanol with 30-40 parts by weight of deionized water, adjust the pH value to 4-5, add 5 parts by weight of octadecyltrimethoxysilane and mix evenly, add hydroxylated two-dimensional hexagonal boron nitride nanosheets, disperse by ultrasonication, and react at 80-85℃ for 10-12h under nitrogen protection; filter, wash and dry to obtain modified two-dimensional hexagonal boron nitride nanosheets.

[0016] By employing the above technical solution, unmodified hexagonal boron nitride tends to agglomerate in acrylate pressure-sensitive adhesive systems, leading to the inability of the underlying layer to cure and reduce tack. However, after modification with octadecyltrimethoxysilane, the 18-carbon aliphatic chains extend around the nanosheets. This long, straight-chain structure generates van der Waals attraction and chain entanglement effects with the acrylate copolymer molecular chains in the pressure-sensitive adhesive system. This allows the nanosheets to be uniformly dispersed in the adhesive in a single layer or few layers, without affecting UV light penetration, and also strengthens the cohesive force of the adhesive during curing. Encapsulated by the long-chain octadecyl group, the two-dimensional boron nitride nanosheets exhibit high hydrophobicity. The combination of this ultra-long hydrophobic chain and the two-dimensional rigid sheet improves the acid penetration resistance of the pressure-sensitive adhesive system.

[0017] Furthermore, in step (2), the mass ratio of octadecyltrimethoxysilane to hydroxylated hexagonal boron nitride nanosheets is 1:(1.9~2.2).

[0018] By adopting the above technical solution, if the silane ratio is too low, the exposed polar hydroxyl groups of the nanosheets are prone to secondary aggregation in the colloid and are easily attacked by acid from the defect. If the silane ratio is too high, the excess silane is not only prone to self-condensation, but also causes the steric hindrance on the surface of the nanosheets to be too large, which hinders them from aligning in parallel in the horizontal direction in the subsequent coating process.

[0019] Furthermore, the buffer layer is prepared by solidifying a buffer solution; the preparation method of the buffer solution includes the following steps: Mix 25-40 parts by weight of butanone and 25-40 parts by weight of ethyl acetate evenly, add 100-110 parts by weight of hydroxyl-terminated polyester polyurethane resin and mix evenly, slowly add 0.5-2 parts by weight of epoxy-containing silane coupling agent and mix evenly, then add 5-10 parts by weight of hexamethylene diisocyanate trimer and mix evenly to obtain a buffer solution.

[0020] By adopting the above technical solution, the silanol at one end of the epoxy-containing silane coupling agent forms a Si-OC covalent bond with the polar groups on the substrate surface, while the epoxy group at the other end crosslinks with the carboxyl / hydroxyl groups in the pressure-sensitive adhesive layer; this eliminates the microscopic physical gaps at the interface between the substrate and the adhesive layer, preventing acid leakage from the bottom layer; at the same time, the aliphatic polyurethane network can effectively absorb the interfacial stress generated during the UV curing shrinkage of the adhesive, avoiding adhesive layer peeling and residual adhesive when the film is peeled off.

[0021] Furthermore, the buffer layer is prepared by coating the buffer solution onto the substrate layer, baking it at 75~80℃ for 1~2 minutes in zone one, and baking it at 105~110℃ for 2~3 minutes in zone two.

[0022] By adopting the above technical solution and using gradient heating baking, the solvent in the buffer solution gradually evaporates, avoiding defects such as bubbles and cracks in the buffer layer caused by excessively high or rapid baking temperature. At the same time, it ensures that the buffer solution is fully solidified to form a stable buffer layer, which can better play its buffering and bonding role.

[0023] Furthermore, the thickness of the substrate layer is 50~100μm, the thickness of the buffer layer is 1~3μm, the thickness of the pressure-sensitive adhesive layer is 15~25μm, and the thickness of the release film layer is 25~75μm.

[0024] By adopting the above technical solution, the thickness of the buffer layer is limited to 1~3μm. If it is less than 1μm, it cannot completely cover the microscopic unevenness of the substrate surface, resulting in acid leakage blind spots. If it is greater than 3μm, the cohesion of the buffer layer itself will decrease, and internal tearing will easily occur during film removal, resulting in residual adhesive. At the same time, the pressure-sensitive adhesive thickness of 15~25μm provides sufficient free volume depth to construct the acid-resistant system, while avoiding glass warping stress caused by excessive shrinkage during UV curing of thick adhesive layers. Optimizing the thickness ratio of each layer ensures that the film as a whole possesses good flexibility, acid resistance, and adhesion.

[0025] Secondly, the present invention provides a method for preparing the above-mentioned UV-resistant flexible glass acid-resistant thin film, comprising the following steps: S1: A buffer solution is uniformly coated on one side of the substrate layer and baked to form the buffer layer; S2: Mix the acrylate copolymer adhesive, modified two-dimensional hexagonal boron nitride nanosheets, crosslinking agent and photoinitiator evenly, degas, and obtain pressure-sensitive adhesive; S3: Apply the pressure-sensitive adhesive liquid onto the release film layer, and then perform gradient temperature curing: Zone 1 is baked at 60~65℃ for 1~2 min, Zone 2 at 90~95℃ for 1~2 min, and Zone 3 at 110~115℃ for 2~3 min to form the pressure-sensitive adhesive layer. S4: The substrate layer with the buffer layer in step S1 is bonded to the release film layer with the pressure-sensitive adhesive layer in step S3, and then cured and crosslinked to obtain the UV-resistant flexible glass acid-resistant film.

[0026] By adopting the above technical solution, the preparation process steps are clear and highly operable. Gradient temperature curing can ensure that the pressure-sensitive adhesive is fully cured, degassing treatment can avoid the appearance of air bubble defects in the pressure-sensitive adhesive layer, and post-lamination curing crosslinking can enhance the bonding strength between each layer and ensure the overall stability of the film performance.

[0027] In summary, the beneficial effects of this invention are: The acrylic copolymer adhesive of this invention, through copolymerization and grafting reactions, combined with modified two-dimensional hexagonal boron nitride nanosheets, enables the pressure-sensitive adhesive layer to possess both strong acid resistance and UV-controlled tack reduction effect, avoiding problems such as acid seepage, swelling, and residual adhesive during etching and peeling. The buffer layer, pressure-sensitive adhesive layer, and other layers are tightly bonded and have stable performance. The buffer layer can alleviate stress impact, and the thickness of each layer is adapted to further ensure the integrity of the ultra-thin flexible glass etching process and improve product yield. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments.

[0029] Preparation Examples 1-4: Preparation of Acrylic Ester Copolymer Liquids Preparation Example 1 The preparation method of the acrylate copolymer adhesive in this example includes the following specific steps: (A) Mix 320g of isobornyl acrylate, 270g of dodecyl methacrylate, 110g of isooctyl acrylate, 50g of acrylic acid, and 130g of hydroxyethyl acrylate with 2.8g of initiator to obtain a mixture; add 1200g of ethyl acetate to a reaction vessel, purge the air in the vessel with high-purity nitrogen for 30 minutes, raise the temperature to 75°C, and add the mixture dropwise to the reaction vessel; after the dropwise addition is complete, raise the temperature to 85°C and react for 1.2h; mix 1.2g of initiator with 12g of ethyl acetate, add the mixture to the reaction vessel in two portions, and continue the reaction for 3h. (B) Lower the temperature to 45°C, stop the nitrogen flow, and instead introduce dry air. Add 0.8g of dibutyltin dilaurate and 0.2g of hydroquinone monomethyl ether and mix well. Under light-protected conditions, add 85g of ethyl isocyanate acrylate dropwise and react for 5 hours. Adjust the solid content to 45% with ethyl acetate, filter, and the filtrate is the acrylate copolymer solution.

[0030] Preparation Example 2 The preparation method of the acrylate copolymer adhesive in this example includes the following specific steps: (A) Mix 280g of isobornyl acrylate, 290g of dodecyl methacrylate, 130g of isooctyl acrylate, 35g of acrylic acid, and 120g of hydroxyethyl acrylate with 3.5g of initiator to obtain a mixture; add 1050g of ethyl acetate to the reactor, purge the air in the reactor with high-purity nitrogen for 30 minutes, raise the temperature to 80°C, and add the mixture dropwise to the reactor; after the dropwise addition is complete, raise the temperature to 85°C and react for 1.5h; mix 1.5g of initiator with 12g of ethyl acetate, add the mixture to the reactor in two portions, and continue the reaction for 2.5h. (B) Lower the temperature to 45°C, stop the nitrogen gas flow, and instead introduce dry air. Add 1g of dibutyltin dilaurate and 0.3g of hydroquinone monomethyl ether and mix well. Under light-protected conditions, add 90g of ethyl isocyanate acrylate dropwise and react for 6 hours. Adjust the solid content to 43% with ethyl acetate, filter, and the filtrate is the acrylate copolymer solution.

[0031] Preparation Example 3 The preparation method of the acrylate copolymer adhesive in this example includes the following specific steps: (A) Mix 265g of isobornyl acrylate, 265g of dodecyl methacrylate, 125g of isooctyl acrylate, 30g of acrylic acid, and 140g of hydroxyethyl acrylate with 1.4g of initiator to obtain a mixture; add 1100g of ethyl acetate to the reactor, purge the air in the reactor with high-purity nitrogen for 30 minutes, raise the temperature to 78°C, and add the mixture dropwise to the reactor; after the dropwise addition is complete, raise the temperature to 85°C and react for 1.5h; mix 0.6g of initiator with 4.8g of ethyl acetate, add the mixture to the reactor in two portions, and continue the reaction for 2h. (B) Lower the temperature to 43°C, stop the nitrogen gas flow, and instead introduce dry air. Add 0.6g of dibutyltin dilaurate and 0.25g of hydroquinone monomethyl ether and mix well. Under light-protected conditions, add 60g of ethyl isocyanate acrylate dropwise and react for 4 hours. Adjust the solid content to 40% with ethyl acetate, filter, and the filtrate is the acrylate copolymer solution.

[0032] Preparation Example 4 The preparation method of the acrylate copolymer adhesive in this example includes the following specific steps: (A) Mix 310g of isobornyl acrylate, 270g of dodecyl methacrylate, 100g of isooctyl acrylate, 45g of acrylic acid, and 110g of hydroxyethyl acrylate with 2.1g of initiator to obtain a mixture; add 1330g of ethyl acetate to the reactor, purge the air in the reactor with high-purity nitrogen for 30min, raise the temperature to 75℃, and add the mixture dropwise to the reactor; after the dropwise addition is complete, raise the temperature to 80℃ and react for 1.3h; mix 0.9g of initiator with 9g of ethyl acetate, add the mixture to the reactor in two portions, and continue the reaction for 3h. (B) Lower the temperature to 45°C, stop the nitrogen gas flow, and instead introduce dry air. Add 0.5g of dibutyltin dilaurate and 0.4g of hydroquinone monomethyl ether and mix well. Under light-protected conditions, add 75g of ethyl isocyanate acrylate dropwise and react for 4.5h. Adjust the solid content to 45% with ethyl acetate, filter, and the filtrate is the acrylate copolymer solution.

[0033] Preparation Examples 5-8: Preparation of Modified Two-Dimensional Hexagonal Boron Nitride Nanosheets Preparation Example 5 The preparation method of the modified two-dimensional hexagonal boron nitride nanosheets in this example includes the following specific steps: (1) 10g of hexagonal boron nitride was added to 110g of NaOH aqueous solution with a concentration of 5mol / L and ultrasonically treated at room temperature at 800W and 20kHz for 1.5h. The suspension was then transferred to a high-pressure reactor and kept at 165℃ for 24h. After the reaction was completed, the mixture was cooled to room temperature, the dispersion was collected, and the mixture was washed by centrifugation with deionized water until the pH of the supernatant was neutral. The supernatant was then dried in a vacuum drying oven at 60℃ for 12h to obtain hydroxylated two-dimensional hexagonal boron nitride nanosheets. (2) Mix 170g of anhydrous ethanol with 30g of deionized water, adjust the pH to 5 using glacial acetic acid to obtain a mixed solvent; slowly add 5g of octadecyltrimethoxysilane to the above mixed solvent, stir at room temperature for 1h, add 10.5g of hydroxylated nanosheets, and ultrasonically disperse for 30min; then transfer to a three-necked flask, and heat to 80℃ for 12h under nitrogen protection; after the reaction is completed, filter while hot, wash repeatedly with anhydrous ethanol 5 times, and dry in an 80℃ vacuum drying oven for 24h to obtain modified two-dimensional hexagonal boron nitride nanosheets.

[0034] Preparation Example 6 The preparation method of the modified two-dimensional hexagonal boron nitride nanosheets in this example includes the following specific steps: (1) 10g of hexagonal boron nitride was added to 100g of NaOH aqueous solution with a concentration of 5mol / L and ultrasonically treated at room temperature at 800W and 20kHz for 1.5h. The suspension was then transferred to a high-pressure reactor and kept at 160℃ for 21h. After the reaction was completed, the mixture was cooled to room temperature, the dispersion was collected, and the mixture was washed by centrifugation with deionized water until the pH of the supernatant was neutral. The supernatant was then dried in a vacuum drying oven at 60℃ for 12h to obtain hydroxylated two-dimensional hexagonal boron nitride nanosheets. (2) Mix 160g of anhydrous ethanol with 35g of deionized water, and adjust the pH to 4 using glacial acetic acid to obtain a mixed solvent; slowly add 5g of octadecyltrimethoxysilane to the above mixed solvent, stir at room temperature for 1h, add 10g of hydroxylated nanosheets, and ultrasonically disperse for 30min; then transfer to a three-necked flask, and under nitrogen protection, heat to 82℃ and react for 11h; after the reaction is completed, filter while hot, and wash repeatedly with anhydrous ethanol 5 times, and dry in an 80℃ vacuum drying oven for 24h to obtain modified two-dimensional hexagonal boron nitride nanosheets.

[0035] Preparation Example 7 The preparation method of the modified two-dimensional hexagonal boron nitride nanosheets in this example includes the following specific steps: (1) 10g of hexagonal boron nitride was added to 105g of NaOH aqueous solution with a concentration of 5mol / L and ultrasonically treated at room temperature at 800W and 20kHz for 1.8h. The suspension was then transferred to a high-pressure reactor and kept at 155℃ for 22h. After the reaction was completed, the mixture was cooled to room temperature, the dispersion was collected, and the mixture was washed by centrifugation with deionized water until the pH of the supernatant was neutral. The supernatant was then dried in a vacuum drying oven at 60℃ for 12h to obtain hydroxylated two-dimensional hexagonal boron nitride nanosheets. (2) Mix 170g of anhydrous ethanol with 30g of deionized water, and adjust the pH to 4 using glacial acetic acid to obtain a mixed solvent; slowly add 5g of octadecyltrimethoxysilane to the above mixed solvent, stir at room temperature for 1h, add 11g of hydroxylated nanosheets, and ultrasonically disperse for 30min; then transfer to a three-necked flask, and heat to 80℃ for 10h under nitrogen protection; after the reaction is completed, filter while hot, wash repeatedly with anhydrous ethanol 5 times, and dry in an 80℃ vacuum drying oven for 24h to obtain modified two-dimensional hexagonal boron nitride nanosheets.

[0036] Preparation Example 8 The preparation method of the modified two-dimensional hexagonal boron nitride nanosheets in this example includes the following specific steps: (1) 10g of hexagonal boron nitride was added to 110g of NaOH aqueous solution with a concentration of 5mol / L. The solution was ultrasonically treated at room temperature with a power of 800W and a frequency of 20kHz for 2h. The suspension was then transferred to a high-pressure reactor and kept at 165℃ for 20h. After the reaction was completed, the solution was cooled to room temperature, the dispersion was collected, and the solution was washed by centrifugation with deionized water multiple times until the pH of the supernatant was neutral. The solution was then dried in a vacuum drying oven at 60℃ for 12h to obtain hydroxylated two-dimensional hexagonal boron nitride nanosheets. (2) Mix 165g of anhydrous ethanol with 40g of deionized water, adjust the pH to 5 using glacial acetic acid to obtain a mixed solvent; slowly add 5g of octadecyltrimethoxysilane to the above mixed solvent, stir at room temperature for 1h, add 11g of hydroxylated nanosheets, and ultrasonically disperse for 30min; then transfer to a three-necked flask, and under nitrogen protection, heat to 85℃ and react for 10h; after the reaction is completed, filter while hot, wash repeatedly with anhydrous ethanol 5 times, and dry in an 80℃ vacuum drying oven for 24h to obtain modified two-dimensional hexagonal boron nitride nanosheets.

[0037] Preparation Examples 9-11: Preparation of Buffer Solutions Preparation Example 9 The specific steps of preparing a buffer solution in this preparation example are as follows: Stir 40g of butanone and 40g of ethyl acetate for 15 minutes, add 110g of hydroxyl-terminated polyester polyurethane resin (solid content 30%, molecular weight about 30,000) and stir for 15 minutes, slowly add 1.5g of silane coupling agent KH-560 and stir for 30 minutes, then add 8g of hexamethylene diisocyanate trimer and stir for 10 minutes to obtain a buffer solution.

[0038] Preparation Example 10 The specific steps of preparing a buffer solution in this preparation example are as follows: Stir 25g of butanone and 25g of ethyl acetate for 15 minutes, add 110g of hydroxyl-terminated polyester polyurethane resin and stir for 15 minutes, slowly add 1g of silane coupling agent KH-560 and stir for 30 minutes, then add 6g of hexamethylene diisocyanate trimer and stir for 10 minutes to obtain a buffer solution.

[0039] Preparation Example 11 The specific steps of preparing a buffer solution in this preparation example are as follows: Stir 30g of butanone and 30g of ethyl acetate for 15 minutes, add 105g of hydroxyl-terminated polyester polyurethane resin and stir for 15 minutes, slowly add 0.8g of silane coupling agent KH-560 and stir for 30 minutes, then add 6.5g of hexamethylene diisocyanate trimer and stir for 10 minutes to obtain a buffer solution.

[0040] Example Example 1 This embodiment of a UV-resistant, acid-resistant, and adhesive-resistant flexible glass film includes, from top to bottom, a substrate layer, a buffer layer, a pressure-sensitive adhesive layer, and a release film layer. The pressure-sensitive adhesive layer is prepared from the following raw materials by weight: Preparation Example 1: 103g of acrylate copolymer solution, Preparation Example 5: 8g of modified two-dimensional hexagonal boron nitride nanosheets, 1.2g of crosslinking agent, and 3g of photoinitiator; The crosslinking agent is hexamethylene diisocyanate trimer, and the photoinitiator is 1-hydroxycyclohexylphenyl ketone. The buffer layer was prepared by solidifying the buffer solution obtained in Preparation Example 9.

[0041] The preparation method of the UV-resistant and acid-resistant flexible glass film according to this embodiment includes the following steps: S1: A buffer layer with a thickness of 2.5 μm is formed by uniformly coating a single side of a PET substrate layer with a thickness of 70 μm, baking at 75 °C for 1 min in zone 1, and baking at 110 °C for 2 min in zone 2. S2: Mix the acrylate copolymer solution, modified two-dimensional hexagonal boron nitride nanosheets, crosslinking agent and photoinitiator and stir for 30 min, then degas to obtain pressure-sensitive adhesive solution; S3: Apply pressure-sensitive adhesive liquid onto a release film layer with a thickness of 55μm, and then perform gradient temperature curing: Zone 1 is baked at 65℃ for 2min, Zone 2 at 95℃ for 1min, and Zone 3 at 110℃ for 2min to form a pressure-sensitive adhesive layer with a thickness of 22μm. S4: The substrate layer with buffer layer in step S1 is bonded to the release film layer with pressure-sensitive adhesive layer in step S3, and cured at 50°C for 48 hours to obtain UV-resistant flexible glass acid-resistant film.

[0042] Example 2 This embodiment of a UV-resistant, acid-resistant, and adhesive-resistant flexible glass film includes, from top to bottom, a substrate layer, a buffer layer, a pressure-sensitive adhesive layer, and a release film layer. The pressure-sensitive adhesive layer is prepared from the following raw materials by weight: Preparation Example 3: 100g of acrylate copolymer solution, Preparation Example 5: 5.5g of modified two-dimensional hexagonal boron nitride nanosheets, 1g of crosslinking agent, and 2g of photoinitiator; The crosslinking agent is hexamethylene diisocyanate trimer, and the photoinitiator is 1-hydroxycyclohexylphenyl ketone. The buffer layer was prepared by solidifying the buffer solution obtained in Preparation Example 9.

[0043] The preparation method of the UV-resistant and acid-resistant flexible glass film according to this embodiment includes the following steps: S1: A buffer layer with a thickness of 1.5 μm is formed by uniformly coating a single side of a 60 μm PET substrate layer, baking at 75°C for 1.5 min in zone 1, and baking at 105°C for 3 min in zone 2. S2: Mix the acrylate copolymer solution, modified two-dimensional hexagonal boron nitride nanosheets, crosslinking agent and photoinitiator and stir for 30 min, then degas to obtain pressure-sensitive adhesive solution; S3: Apply pressure-sensitive adhesive liquid onto a release film layer with a thickness of 40μm, and then perform gradient temperature curing: Zone 1 is baked at 62℃ for 2min, Zone 2 at 90℃ for 2min, and Zone 3 at 110℃ for 2min to form a pressure-sensitive adhesive layer with a thickness of 15μm. S4: The substrate layer with buffer layer in step S1 is bonded to the release film layer with pressure-sensitive adhesive layer in step S3, and cured at 50°C for 48 hours to obtain UV-resistant flexible glass acid-resistant film.

[0044] Example 3 This embodiment of a UV-resistant, acid-resistant, and adhesive-resistant flexible glass film includes, from top to bottom, a substrate layer, a buffer layer, a pressure-sensitive adhesive layer, and a release film layer. The pressure-sensitive adhesive layer is prepared from the following raw materials by weight: Preparation Example 3: 105g of acrylate copolymer solution, Preparation Example 8: 7g of modified two-dimensional hexagonal boron nitride nanosheets, 0.8g of crosslinking agent, and 3g of photoinitiator; The crosslinking agent is hexamethylene diisocyanate trimer, and the photoinitiator is 1-hydroxycyclohexylphenyl ketone. The buffer layer was prepared by solidifying the buffer solution obtained in Preparation Example 10.

[0045] The preparation method of the UV-resistant and acid-resistant flexible glass film according to this embodiment includes the following steps: S1: A buffer layer with a thickness of 2.5 μm is formed by uniformly coating one side of a PET substrate layer with a thickness of 75 μm, baking at 80℃ for 2 min in zone 1, and baking at 110℃ for 3 min in zone 2. S2: Mix the acrylate copolymer solution, modified two-dimensional hexagonal boron nitride nanosheets, crosslinking agent and photoinitiator and stir for 30 min, then degas to obtain pressure-sensitive adhesive solution; S3: Apply pressure-sensitive adhesive liquid onto a release film layer with a thickness of 45μm, and then perform gradient temperature curing: Zone 1 is baked at 65℃ for 1min, Zone 2 at 90℃ for 1.5min, and Zone 3 at 110℃ for 3min to form a pressure-sensitive adhesive layer with a thickness of 20μm. S4: The substrate layer with buffer layer in step S1 is bonded to the release film layer with pressure-sensitive adhesive layer in step S3, and cured at 50°C for 48 hours to obtain UV-resistant flexible glass acid-resistant film.

[0046] Example 4 The difference between this embodiment and Embodiment 1 is that the pressure-sensitive adhesive layer is prepared from the following raw materials by weight: Preparation Example 1: 102g of acrylate copolymer solution, Preparation Example 6: 6.5g of modified two-dimensional hexagonal boron nitride nanosheets, 1.7g of crosslinking agent, and 3g of photoinitiator; The rest are the same as in Example 1.

[0047] Example 5 The difference between this embodiment and Embodiment 1 is that the thickness of the substrate layer is 80 μm, the thickness of the buffer layer is 3 μm, and the thickness of the pressure-sensitive adhesive layer is 18 μm. The rest are the same as in Example 1.

[0048] Comparative Example 1 The difference from Example 1 is that no modified two-dimensional hexagonal boron nitride nanosheets are added to the pressure-sensitive adhesive layer in this comparative example; otherwise, it is the same as Example 1.

[0049] Comparative Example 2 The difference from Example 1 is that: in this comparative example, an equal amount of unmodified hexagonal boron nitride is used instead of modified two-dimensional hexagonal boron nitride nanosheets, while all other aspects are the same as in Example 1.

[0050] Comparative Example 3 The difference from Example 1 is that the acrylate copolymer liquid in this comparative pressure-sensitive adhesive layer is isoborneol acrylate-acrylate copolymer (dodecyl methacrylate and ethyl isocyanate were not introduced), while the rest are the same as in Example 1.

[0051] Comparative Example 4 The difference from Example 1 is that: no buffer layer is set in this comparative example, and the PET substrate is directly coated with pressure-sensitive adhesive layer, while the rest is the same as in Example 1.

[0052] Related performance tests The UV-resistant flexible glass acid-resistant thin films prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were subjected to relevant performance tests, and the test results are shown in Table 1.

[0053] Initial peel force (180°): Referring to GB / T 2792-2014, the sample was attached to a clean flexible glass surface and rolled back and forth 3 times with a 2kg roller. After being placed at room temperature for 20 minutes, the sample was peeled off at a speed of 300mm / min using a universal tensile testing machine to test the initial peel force.

[0054] Peel strength after UV exposure: The above samples were irradiated with a UV lamp (wavelength 365nm, energy 500mJ / cm²) and the peel strength was tested using the same method.

[0055] Acid resistance test: The sample was attached to flexible glass and completely immersed in a mixed acid etching solution (hydrofluoric acid: sulfuric acid: water = 1:2:5, mass ratio) at 60℃ for 80 minutes. After immersion, the sample was removed and the adhesive layer and interface condition were observed. Excellent: The adhesive layer is free from whitening, bubbling, acid seepage, and edge lifting; Good: Slight edge lifting (≤0.5mm), with no traces of acid seepage; Poor: The adhesive layer is white or bubbling, or there are obvious glass etching spots caused by acid seepage.

[0056] Table 1 Test Results

[0057] Comparative Example 1: Lacking the physical barrier formed by two-dimensional materials, in a strong acid etching environment, the acid micro-penetrates into the colloid, destroying the UV-reactive double bonds grafted on the side chains of the acrylate copolymer. This results in insufficient crosslinking density and a decreased anti-adhesion effect after UV irradiation. Ultimately, this manifests as easy breakage of the glass during film removal, accompanied by significant adhesive residue.

[0058] Comparative Example 2: Untreated hexagonal boron nitride has poor dispersibility in the acrylate system, forming micron-sized agglomerates, which damages the surface smoothness and wettability of the pressure-sensitive adhesive layer, resulting in a decrease in initial peel force. At the same time, the agglomerates have a blocking effect on ultraviolet light, resulting in insufficient curing at the bottom of the adhesive layer, a decrease in the anti-tack function, and an increase in peel force after UV exposure.

[0059] Comparative Example 3: The lack of flexible segments provided by long-chain alkyl groups resulted in weak adhesion of the adhesive layer to the flexible glass surface and insufficient initial peel force; at the same time, the lack of UV-reactive side chains resulted in low de-adhesion efficiency; and the insufficient hydrophobicity and cross-linking structure resulted in poor acid resistance.

[0060] Comparative Example 4: Without a primer buffer layer, the anchoring force between the pressure-sensitive adhesive and the PET substrate is insufficient, and its bonding strength is lower than that between the pressure-sensitive adhesive and flexible glass. Acid easily penetrates capillarily from the interface between PET and the adhesive layer, reducing the acid resistance effect; during peeling, interface delamination and localized edge lifting are likely to occur, but the adhesive layer as a whole leaves no residue.

[0061] The acid-resistant films prepared in Examples 1 to 5 of this invention all maintain an initial peel force in a moderate range of 20 to 25 N / 25 mm, ensuring adhesion during strong acid etching. After irradiation with 365 nm ultraviolet light, the peel force drops to below 0.05 N / 25 mm, the film peeling process is smooth and the glass surface achieves optical-grade residue-free performance, while maintaining excellent acid resistance.

[0062] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A UV-resistant, non-adhesive, flexible glass acid-resistant film, characterized in that, From top to bottom, it includes a substrate layer, a buffer layer, a pressure-sensitive adhesive layer, and a release film layer; The pressure-sensitive adhesive layer is prepared from the following raw materials in parts by weight: 100-105 parts of acrylate copolymer adhesive, 5-8 parts of modified two-dimensional hexagonal boron nitride nanosheets, 0.5-2 parts of crosslinking agent, and 2-4 parts of photoinitiator; The acrylate copolymer solution is prepared by copolymerizing isoborneol acrylate, dodecyl methacrylate, isooctyl acrylate, acrylic acid and hydroxyethyl acrylate, and then grafting it with ethyl isocyanate acrylate.

2. The UV-resistant, acid-resistant flexible glass film according to claim 1, characterized in that, The preparation method of the acrylate copolymer adhesive includes the following steps: (A) Mix isobornyl acrylate, dodecyl methacrylate, isooctyl acrylate, acrylic acid and hydroxyethyl acrylate with a portion of the initiator to obtain a mixture; under nitrogen protection, heat the reaction vessel containing ethyl acetate to 75-80°C, and add the mixture dropwise to the reaction vessel; after the dropwise addition is complete, heat to 80-85°C and react for 1-1.5 hours; mix the remaining initiator with ethyl acetate at a mass ratio of 1:(7-10), add the mixture to the reaction vessel in two portions, and continue the reaction for 2-3 hours. (B) Lower the temperature to 40~45℃, stop the nitrogen gas supply, and replace it with dry air. Add dibutyltin dilaurate and hydroquinone monomethyl ether and mix well. Under light-protected conditions, add ethyl isocyanate acrylate dropwise and react for 4~6 hours. Adjust the solid content to 40%~45% with ethyl acetate, filter, and the filtrate is the acrylate copolymer solution.

3. The UV-resistant, acid-resistant flexible glass film according to claim 2, characterized in that, The mass ratio of isoborneol acrylate, dodecyl methacrylate, isooctyl acrylate, acrylic acid, hydroxyethyl acrylate, ethyl isocyanate acrylate, initiator, dibutyltin dilaurate, and hydroquinone monomethyl ether is (25~35):(25~30):(10~15):(2~5):(10~15):(5~10):(0.2~0.5):(0.05~0.1):(0.01~0.05).

4. The UV-resistant, acid-resistant flexible glass film according to claim 2, characterized in that, In step (A), the amount of ethyl acetate pre-loaded into the reactor is 100% to 150% of the total mass of isobornyl acrylate, dodecyl methacrylate, isooctyl acrylate, acrylic acid, hydroxyethyl acrylate, ethyl isocyanate, initiator, dibutyltin dilaurate, and hydroquinone monomethyl ether.

5. The UV-resistant, acid-resistant flexible glass film according to claim 1, characterized in that, The method for preparing the modified two-dimensional hexagonal boron nitride nanosheets includes the following steps: (1) Mix 10 parts by mass of hexagonal boron nitride with 100-110 parts by mass of NaOH aqueous solution with a concentration of 5 mol / L, sonicate for 1.5-2 h, keep warm at 155-165℃ for 20-24 h, cool, wash, and dry to obtain hydroxylated two-dimensional hexagonal boron nitride nanosheets. (2) Mix 160-170 parts by weight of anhydrous ethanol with 30-40 parts by weight of deionized water, adjust the pH value to 4-5, add 5 parts by weight of octadecyltrimethoxysilane and mix evenly, add hydroxylated two-dimensional hexagonal boron nitride nanosheets, disperse by ultrasonication, and react at 80-85℃ for 10-12h under nitrogen protection; filter, wash and dry to obtain modified two-dimensional hexagonal boron nitride nanosheets.

6. The UV-resistant, acid-resistant flexible glass film according to claim 5, characterized in that, In step (2), the mass ratio of octadecyltrimethoxysilane to hydroxylated two-dimensional hexagonal boron nitride nanosheets is 1:(1.9~2.2).

7. The UV-resistant, acid-resistant flexible glass film according to claim 1, characterized in that, The buffer layer is prepared by solidifying a buffer solution; the preparation method of the buffer solution includes the following steps: Mix 25-40 parts by weight of butanone and 25-40 parts by weight of ethyl acetate evenly, add 100-110 parts by weight of hydroxyl-terminated polyester polyurethane resin and mix evenly, slowly add 0.5-2 parts by weight of epoxy-containing silane coupling agent and mix evenly, then add 5-10 parts by weight of hexamethylene diisocyanate trimer and mix evenly to obtain a buffer solution.

8. The UV-resistant, acid-resistant flexible glass film according to claim 7, characterized in that, The buffer layer is prepared by coating the buffer solution onto the substrate layer, baking it at 75-80°C in zone one for 1-2 minutes, and baking it at 105-110°C in zone two for 2-3 minutes.

9. The UV-resistant, acid-resistant flexible glass film according to claim 1, characterized in that, The thickness of the substrate layer is 50~100μm, the thickness of the buffer layer is 1~3μm, the thickness of the pressure-sensitive adhesive layer is 15~25μm, and the thickness of the release film layer is 25~75μm.

10. A method for preparing a UV-resistant, acid-resistant flexible glass film according to any one of claims 1-9, characterized in that, Includes the following steps: S1: A buffer solution is uniformly coated on one side of the substrate layer and baked to form the buffer layer; S2: Mix the acrylate copolymer adhesive, modified two-dimensional hexagonal boron nitride nanosheets, crosslinking agent and photoinitiator evenly, degas, and obtain pressure-sensitive adhesive; S3: Apply the pressure-sensitive adhesive liquid onto the release film layer, and then perform gradient temperature curing: Zone 1 is baked at 60~65℃ for 1~2 min, Zone 2 at 90~95℃ for 1~2 min, and Zone 3 at 110~115℃ for 2~3 min to form the pressure-sensitive adhesive layer. S4: The substrate layer with the buffer layer in step S1 is bonded to the release film layer with the pressure-sensitive adhesive layer in step S3, and then cured and crosslinked to obtain the UV-resistant flexible glass acid-resistant film.

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