UTG (Untranslated Glycol) laminated assembly for folding screen and preparation method of UTG laminated assembly

Abstract

The invention relates to the field of folding screen glass cover plates, and particularly discloses a UTG laminated assembly for a folding screen and a preparation method of the UTG laminated assembly. The UTG laminated assembly for the folding screen sequentially comprises a functional base film layer, a first thermoplastic polymer layer, an ultra-thin glass layer and a second thermoplastic polymer layer from top to bottom, the functional base film layer is prepared from the following raw materials in parts by weight: polyimide resin, polyarylene ether nitrile, gas-phase nano silicon dioxide, polypentafluoropropyl methacrylate, modified black phosphorus quantum dots, grafted microcrystalline cellulose, an accelerant and an ultraviolet light absorber; the grafted microcrystalline cellulose is obtained by grafting polymethyl methacrylate on microcrystalline cellulose; the modified black phosphorus quantum dots are obtained by modifying black phosphorus quantum dots through a zinc-based metal organic framework material. The UTG laminated assembly is high in impact resistance and can have high hardness and light transmittance, and it can be guaranteed that the folding screen has good appearance and visual experience after being used for a long time.

Description

Technical Field

[0001] The present application relates to the field of folding screen glass covers, and more specifically, to a UTG lamination assembly for folding screens and a preparation method thereof. Background Art

[0002] Currently, in the field of foldable display devices, ultra-thin glass (UTG) is generally used as a flexible cover material. UTG with a small thickness has excellent bending properties and can meet the stringent requirements of flexible screens for extremely small radius of curvature. However, the mechanical properties of UTG are negatively correlated with its thickness: as the thickness decreases, its impact resistance decreases significantly, resulting in a critical failure height of usually less than 10 mm in the pen-drop test (simulating drops or collisions in daily use), and there is a high risk of crack propagation. Such reliability defects seriously restrict the large-scale application of UTG in scenarios such as mobile terminals.

[0003] To improve the impact resistance of UTG, existing technologies mostly use multi-layer composite structures for reinforcement. For example, a patent document with the publication number CN212749798U discloses a foldable glass cover with a touch function, including ultra-thin glass. A first optical adhesive layer, a first touch sensor, and a first PET layer are sequentially provided on the upper surface of the ultra-thin glass, and a second optical adhesive layer, a second touch sensor, and a second PET layer are sequentially provided on the lower surface of the ultra-thin glass. The UTG is bonded to a polyethylene terephthalate (PET) film through an optically clear adhesive (OCA) to form a "UTG-OCA-PET" laminated structure.

[0004] Although this flexible folding cover structure improves the impact resistance of UTG to a certain extent, due to the presence of multiple low-modulus OCA adhesive layers and PET films on the UTG, the cover material has the defect of low hardness. Therefore, after the folding screen is used for a period of time, problems such as uneven surface, severe creases, and fingernail marks will appear, affecting the screen appearance and visual experience. In addition, as a protective layer, the light transmittance of the PET film is lower than that of the UTG body. After adding the OCA adhesive layer, the overall light transmittance further decreases, resulting in a loss of screen brightness. At the same time, reflection losses will occur at the interfaces of each layer in the UTG-OCA-PET composite structure, and the total reflectance increases after stacking, significantly reducing the light transmission efficiency. Therefore, the glass covers in related technologies have problems of low hardness and low light transmission efficiency. Summary of the Invention

[0005] In order to improve the hardness and light transmission efficiency of the cover material, and thus ensure that the folding screen still has a good appearance and visual experience under long-term use conditions, the present application provides a UTG lamination assembly for folding screens and a preparation method thereof.

[0006] The UTG lamination component for a foldable screen provided by this application adopts the following technical solution: A UTG lamination component for a foldable screen, which successively includes from top to bottom: a functional base film layer, a first thermoplastic polymer layer, an ultra-thin glass layer, and a second thermoplastic polymer layer; The first thermoplastic polymer layer and the second thermoplastic polymer layer are cured and made from the same thermoplastic polymer composition, and the thermoplastic polymer composition is made from raw materials with the following weight components: 40 - 60 parts of thermoplastic polyurethane elastomer, 20 - 30 parts of polycarbonate, and 1 - 3 parts of nano boron nitride; The functional base film layer is made from raw materials with the following weight components: 60 - 85 parts of polyimide resin, 20 - 30 parts of polyarylether nitrile, 5 - 15 parts of gaseous nano silicon dioxide, 3 - 8 parts of pentafluoropropyl polymethacrylate, 3 - 7 parts of modified black phosphorus quantum dots, 2 - 5 parts of grafted microcrystalline cellulose, 1 - 3 parts of accelerator, and 1 - 3 parts of ultraviolet absorber; The grafted microcrystalline cellulose is obtained by grafting polymethyl methacrylate onto microcrystalline cellulose; The modified black phosphorus quantum dots are obtained by modifying black phosphorus quantum dots with zinc-based metal-organic framework materials.

[0007] By adopting the above technical solution, polyimide resin and polyarylether nitrile have excellent heat resistance, mechanical properties, and chemical stability. The combination of the two provides a basic strength and stability framework for the functional base film layer, enhancing the overall hardness and anti-deformation ability of the base film layer. Nano-scale silicon dioxide is dispersed in the base film, further improving hardness and wear resistance, and reducing the occurrence of unevenness on the surface. The presence of pentafluoropropyl polymethacrylate reduces the surface energy of the base film surface, making the base film have good anti-fouling and anti-fingerprint properties, avoiding the generation of appearance defects such as fingernail marks. At the same time, its good optical properties help to maintain the light transmittance of the base film.

[0008] The modified black phosphorus quantum dots are uniformly dispersed in the base film. The black phosphorus particles themselves have relatively high strength and rigidity, which can effectively resist external forces, significantly improve the hardness of the base film, and reduce problems such as surface depressions and scratches during the use of the folding screen. After modifying the black phosphorus quantum dots with zinc-based metal-organic framework materials (such as ZIF-8), on the one hand, the high porosity and uniform pore size distribution of ZIF-8 reduce the light scattering in the base film; on the other hand, the interaction between the modified black phosphorus quantum dots and other components in the base film is optimized, and their special optoelectronic properties can regulate the absorption and transmission of light, making the transmission of visible light through the base film more uniform and efficient, thereby improving the overall light transmittance. The modified black phosphorus quantum dots and other components in the base film form a synergistic effect. When subjected to impact, they can effectively disperse and absorb the impact energy through their own structural deformation and interaction with surrounding materials, enhance the impact resistance of the base film, protect the ultra-thin glass layer, and reduce the generation of creases.

[0009] Microcrystalline cellulose has relatively high strength and rigidity. By grafting polymethyl methacrylate, its compatibility with other polymers in the base film is improved, forming a good dispersion state and enhanced network structure in the base film, thereby significantly enhancing the mechanical properties such as tensile strength and flexural strength of the base film, and further improving the hardness and anti-deformation ability of the base film. The grafted microcrystalline cellulose forms an enhanced network structure in the base film and interweaves with polymers such as polyimide resin and polyarylether nitrile. This network structure makes the interior of the base film more dense and uniform, reducing internal voids and defects. When light propagates, the obstacles encountered are reduced, and the reflection and scattering are lowered, thereby improving the overall light transmittance.

[0010] The thermoplastic polyurethane elastomer in the thermoplastic polymer layer endows the material with certain flexibility, enabling it to adapt to deformation during folding; polycarbonate provides relatively high strength and rigidity; the addition of nano boron nitride further enhances the hardness and wear resistance. The two thermoplastic polymer layers are closely attached to the functional base film layer and the ultra-thin glass layer, and cooperate with the functional base film layer to jointly improve the hardness of the entire cover plate material.

[0011] This laminated component is directly hot-pressed into a four-layer structure without adding an OCA adhesive layer. The OCA adhesive layer not only has a low modulus, which will affect the hardness of the cover plate, but also increases the number of interfaces, and each interface will generate reflection losses, reducing the light transmission efficiency. This solution reduces the use of the OCA adhesive layer and provides a functional base film layer and thermoplastic polymer layer with good performance, effectively enhancing the hardness and light transmittance of the cover plate material.

[0012] Optionally, the modified black phosphorus quantum dots are prepared by the following method: A. Mix zinc nitrate, 2-methylimidazole, and N,N-dimethylformamide, stir and react at a speed of 500 - 700 r / min for 30 - 50 min, then react at 100 - 120 °C for 20 - 24 h. After the reaction, centrifuge the reaction product, and then wash and dry the reaction product to obtain ZIF-8 powder; B. Take the ZIF-8 powder and mix it with the black phosphorus quantum dot dispersion liquid, ultrasonically treat for 1 - 2 h, then stir and react at 30 - 40 °C at a speed of 200 - 300 r / min for 20 - 24 h. After the reaction, centrifuge the product, and then wash and dry the reaction product to obtain modified black phosphorus quantum dots.

[0013] By adopting the above technical solution, the modified black phosphorus quantum dots prepared by this method, on the one hand, its high porosity and uniform pore size distribution reduce the scattering of light in the base film, and on the other hand, the interaction with other components in the base film is optimized, which can regulate the absorption and transmission of light, improve the overall light transmittance, and at the same time can enhance the impact resistance of the base film and reduce the generation of creases.

[0014] Optionally, in step A, the mass ratio of zinc nitrate, 2-methylimidazole, and N,N-dimethylformamide is 1:(2 - 3):(20 - 30).

[0015] By adopting the above technical solution, this ratio is helpful for preparing ZIF-8 powder with good performance, and then ensuring the performance of the modified black phosphorus quantum dots, so that it can better play the roles of improving the hardness, light transmittance, and impact resistance of the base film, etc.

[0016] Optionally, in step B, the mass concentration of the black phosphorus quantum dot dispersion liquid is 25% - 30%; the mass ratio of the ZIF-8 powder to the black phosphorus quantum dot dispersion liquid is 1:(1 - 3).

[0017] By adopting the above technical solution, the mass concentration of the black phosphorus quantum dot dispersion liquid and the mass ratio of the ZIF-8 powder to the black phosphorus quantum dot dispersion liquid are specified, which is beneficial to obtaining uniformly dispersed and stable-performance modified black phosphorus quantum dots, so that it can more effectively enhance the hardness, improve the light transmittance, and impact resistance in the base film.

[0018] Optionally, the grafted microcrystalline cellulose is prepared by the following method: (1) Add microcrystalline cellulose to the NaOH solution, stir at a speed of 200 - 400 r / min at 60 - 80 °C for 10 - 12 h, filter, and then wash with an ethanol-water mixed solution until the pH of the filtrate is 7 - 8 to obtain surface hydroxyl-activated cellulose; (2) Add surface hydroxyl-activated cellulose, methyl methacrylate, azobisisobutyronitrile, and dimethyl sulfoxide into a reaction vessel. Under nitrogen protection, stir and react at 60 - 70 °C at a rotation speed of 300 - 400 r / min for 8 - 12 h. After the reaction, pour the reaction product into absolute ethanol for precipitation, wash it with absolute ethanol 3 - 5 times after filtration, and finally vacuum dry it at 50 - 60 °C for 12 - 24 h to obtain grafted microcrystalline cellulose.

[0019] The grafted microcrystalline cellulose prepared by this method can form a good dispersion state and enhanced network structure in the base film, significantly improving the mechanical properties of the base film, enhancing the hardness and anti-deformation ability of the base film. At the same time, it makes the interior of the base film more dense and uniform, reduces the hindrance of light propagation, and improves the overall light transmittance.

[0020] Optionally, in step (1), the mass concentration of the NaOH solution is 5% - 10%, and the mass ratio of the microcrystalline cellulose to the NaOH solution is 1:(10 - 15).

[0021] Optionally, the mass ratio of the surface hydroxyl-activated cellulose, methyl methacrylate, azobisisobutyronitrile, and dimethyl sulfoxide in step (2) is (1 - 2):(3 - 4):(0.05 - 0.1):15.

[0022] Optionally, the ultraviolet absorber is thiospiropyran.

[0023] By adopting the above technical solution, thiospiropyran has advantages such as good light responsiveness and a relatively wide absorption wavelength range. Moreover, thiospiropyran has good chemical stability and is not prone to chemical reactions and deterioration during the processing of the glass cover plate and its use environment, and can maintain its ultraviolet absorption and other properties for a long time, ensuring that the folding screen glass cover plate continuously plays a protective and optimizing role during long-term use.

[0024] This application also provides a preparation method for a UTG lamination assembly for a folding screen, adopting the following technical solution: A preparation method for a UTG lamination assembly for a folding screen includes the following steps: S1. Prepare a functional base film layer: Mix polyimide resin, polyarylether nitrile, gas-phase nano-silica, poly(perfluoropropyl methacrylate), modified black phosphorus quantum dots, grafted microcrystalline cellulose, a promoter, an ultraviolet absorber, and a solvent evenly to obtain a base film coating. Coating the base film coating on a polyester release film, and after drying and curing, peel it off from the polyester release film to obtain a functional base film layer; S2, preparing a thermoplastic polymer layer: mixing a thermoplastic polyurethane elastomer, polycarbonate and nano boron nitride to obtain a thermoplastic polymer composition, and then melt-blending and extruding the mixture at 190-200° C. through a twin-screw extruder to form a sheet, and then shearing the mixture to obtain a first thermoplastic polymer layer and a second thermoplastic polymer layer, respectively; S3. Assemble the laminated components: stack the functional base film layer, the first thermoplastic polymer layer, the ultra-thin glass layer and the second thermoplastic polymer layer in sequence, put the stacked four layers of materials into a vacuum hot press, and hot press them at 110-130°C and 1.5-2.5MPa pressure for 15-25 minutes. After the hot pressing is completed, wait for the temperature to cool down to obtain the UTG laminated component for the folding screen.

[0025] The above scheme provides a method for preparing a UTG laminated assembly for a folding screen. The laminated assembly prepared by this method adopts a four-layer structure and is directly hot-pressed without adding an OCA adhesive layer, thereby avoiding the problem that the low modulus of the OCA adhesive layer affects the hardness of the cover plate and increases the interface reflection loss and reduces the light transmittance. At the same time, each layer of material can better exert its performance through this preparation method, effectively enhancing the hardness and light transmittance of the cover plate material.

[0026] Optionally, the temperature during drying and curing in S1 is 80-120° C., and the drying and curing time is 1-3 hours.

[0027] Under the above conditions, the base film coating is fully dried and cured to obtain a functional base film layer with good performance, ensuring its hardness, anti-fouling, anti-fingerprint, light transmittance and other properties, thereby improving the performance of the entire laminated assembly.

[0028] In summary, this application has the following beneficial effects: 1. This application introduces black phosphorus quantum dots modified by zinc-based metal organic framework materials into the base film layer, and the modified black phosphorus quantum dots play a key role in improving the performance of UTG laminated components for folding screens. Its own high strength and rigidity characteristics, like rigid reinforcing particles evenly dispersed in the functional base film layer, effectively resist external forces, significantly enhance the hardness of the base film, and reduce surface depressions and scratches; after modification, the high porosity and uniform pore size distribution of the zinc-based metal organic framework material are used to reduce the scattering of light in the base film, while optimizing the interaction with other components of the base film, regulating light absorption and transmission, and improving the overall light transmittance; when impacted, it synergizes with other components of the base film to deform, disperse and absorb impact energy, enhance the impact resistance of the base film, protect the ultra-thin glass layer, and reduce the generation of creases.

[0029] 2. The grafted microcrystalline cellulose introduced in this application can significantly improve the performance of the functional base film. The graft modification improves the compatibility of microcrystalline cellulose with other polymers in the base film, enabling it to be well-dispersed in the base film and form a reinforcing network structure, interwoven between polymers such as polyimide resin and polyarylether nitrile, greatly enhancing the mechanical properties of the base film such as tensile and bending properties, and further enhancing the hardness and anti-deformation ability of the base film; this reinforcing network structure also makes the interior of the base film denser and more uniform, reducing voids and defects, reducing the hindrance to light propagation, and reducing reflection and scattering, thereby effectively improving the overall light transmittance of the base film.

[0030] 3. The laminated component of this application adopts a four-layer structure of a functional base film layer, a first thermoplastic polymer layer, an ultra-thin glass layer, and a second thermoplastic polymer layer, and through a preparation process of direct hot pressing, effectively overcomes the defects of the prior art. In the four-layer structure, the functional base film layer and the thermoplastic polymer layer act synergistically to endow the component with high hardness; the components in the thermoplastic polymer layer take into account both flexibility and rigidity to ensure folding adaptability. The direct hot pressing process does not require the addition of a low-modulus OCA adhesive layer, reducing the problem of hardness reduction caused by the OCA adhesive layer; at the same time, it reduces the number of interfaces, reduces the interface reflection loss, and improves the light transmission efficiency, ultimately effectively enhancing the hardness and light transmittance of the cover plate material, and ensuring good appearance and visual experience under long-term use of the folding screen. Detailed implementation mode

[0031] The following further elaborates on this application in conjunction with the embodiments.

[0032] Preparation example of modified black phosphorus quantum dots Preparation example 1 The modified black phosphorus quantum dots are prepared by the following method: A. Mix 1 kg of zinc nitrate, 2 kg of 2-methylimidazole, and 20 kg of N,N-dimethylformamide, stir and react at a speed of 500 r / min for 30 min, then react at 100 °C for 20 h. After the reaction, centrifuge the reaction product, and then wash the reaction product alternately with ethanol and DMF 5 times, and vacuum dry at 60 °C for 12 h to obtain ZIF-8 powder; B. Take 1 kg of ZIF-8 powder and mix it with 1 kg of a 25% mass concentration black phosphorus quantum dot dispersion liquid, ultrasonically treat for 1 h, then stir and react at a speed of 200 r / min at 30 °C for 20 h. After the reaction, centrifuge the product, and then wash the reaction product alternately with ethanol and DMF 5 times, and vacuum dry at 40 °C for 12 h to obtain modified black phosphorus quantum dots.

[0033] Preparation example 2 The modified black phosphorus quantum dots are prepared by the following method: A. Mix 1 kg of zinc nitrate, 2.5 kg of 2-methylimidazole, and 25 kg of N,N-dimethylformamide, stir and react at a speed of 600 r / min for 40 min, then react at 110 °C for 22 h. After the reaction is completed, centrifuge the reaction product, and then wash the reaction product alternately with ethanol and DMF 5 times, and vacuum dry at 60 °C for 12 h to obtain ZIF-8 powder; B. Take 1 kg of ZIF-8 powder and mix it with 2 kg of black phosphorus quantum dot dispersion with a mass concentration of 28%, ultrasonically treat for 1.5 h, then stir and react at a speed of 250 r / min at 35 °C for 22 h. After the reaction is completed, centrifuge the product, and then wash the reaction product alternately with ethanol and DMF 5 times, and vacuum dry at 40 °C for 12 h to obtain modified black phosphorus quantum dots.

[0034] Preparation Example 3 The modified black phosphorus quantum dots are prepared by the following method: A. Mix 1 kg of zinc nitrate, 3 kg of 2-methylimidazole, and 30 kg of N,N-dimethylformamide, stir and react at a speed of 700 r / min for 50 min, then react at 120 °C for 24 h. After the reaction is completed, centrifuge the reaction product, and then wash the reaction product alternately with ethanol and DMF 5 times, and vacuum dry at 60 °C for 12 h to obtain ZIF-8 powder; B. Take 1 kg of ZIF-8 powder and mix it with 3 kg of black phosphorus quantum dot dispersion with a mass concentration of 30%, ultrasonically treat for 2 h, then stir and react at a speed of 300 r / min at 40 °C for 24 h. After the reaction is completed, centrifuge the product, and then wash the reaction product alternately with ethanol and DMF 5 times, and vacuum dry at 40 °C for 12 h to obtain modified black phosphorus quantum dots.

[0035] Preparation Example 4 The modified black phosphorus quantum dots are different from those in Preparation Example 1 in that: in step B of this preparation example, the mass concentration of the black phosphorus quantum dot dispersion is 35%.

[0036] Preparation Examples of Grafted Microcrystalline Cellulose Preparation Example 5 The grafted microcrystalline cellulose is prepared by the following method: (1) Add 1 kg of microcrystalline cellulose to 10 kg of NaOH solution with a mass concentration of 5%, stir at a speed of 200 r / min at 60 °C for 10 h, filter, and then wash with a 1:1 mixture of ethanol and water until the pH of the filtrate is 7 to obtain surface hydroxyl-activated cellulose; (2) Add 1 kg of surface hydroxyl-activated cellulose, 3 kg of methyl methacrylate, 0.05 kg of azobisisobutyronitrile, and 15 kg of dimethyl sulfoxide into a reaction kettle. Under nitrogen protection, stir and react at 60 °C at a rotation speed of 300 r / min for 8 h. After the reaction, pour the reaction product into absolute ethanol for precipitation, wash it 3 times with absolute ethanol after filtration, and finally dry it under vacuum at 50 °C for 12 h to obtain grafted microcrystalline cellulose.

[0037] Preparation Example 6 Grafted microcrystalline cellulose is prepared by the following method: (1) Add 2 kg of microcrystalline cellulose into 25 kg of NaOH solution with a mass concentration of 8%. Stir at 70 °C at a rotation speed of 300 r / min for 11 h. After filtration, wash it with a 1:1 mixture of ethanol and water until the pH of the filtrate is 7.5 to obtain surface hydroxyl-activated cellulose. (2) Add 1.5 kg of surface hydroxyl-activated cellulose, 3.5 kg of methyl methacrylate, 0.08 kg of azobisisobutyronitrile, and 15 kg of dimethyl sulfoxide into a reaction kettle. Under nitrogen protection, stir and react at 65 °C at a rotation speed of 350 r / min for 10 h. After the reaction, pour the reaction product into absolute ethanol for precipitation, wash it 4 times with absolute ethanol after filtration, and finally dry it under vacuum at 55 °C for 18 h to obtain grafted microcrystalline cellulose.

[0038] Preparation Example 7 Grafted microcrystalline cellulose is prepared by the following method: (1) Add 2 kg of microcrystalline cellulose into 30 kg of NaOH solution with a mass concentration of 10%. Stir at 80 °C at a rotation speed of 400 r / min for 12 h. After filtration, wash it with a 1:1 mixture of ethanol and water until the pH of the filtrate is 8 to obtain surface hydroxyl-activated cellulose. (2) Add 2 kg of surface hydroxyl-activated cellulose, 4 kg of methyl methacrylate, 0.1 kg of azobisisobutyronitrile, and 15 kg of dimethyl sulfoxide into a reaction kettle. Under nitrogen protection, stir and react at 70 °C at a rotation speed of 400 r / min for 12 h. After the reaction, pour the reaction product into absolute ethanol for precipitation, wash it 5 times with absolute ethanol after filtration, and finally dry it under vacuum at 60 °C for 24 h to obtain grafted microcrystalline cellulose.

[0039] Preparation Example 8 The difference between the grafted microcrystalline cellulose of this preparation example and Preparation Example 1 is that in this preparation example, the surface hydroxyl activation treatment of microcrystalline cellulose is not carried out, that is, step (1) is not carried out, and microcrystalline cellulose is directly used to participate in the grafting reaction in step (2).

[0040] Examples Example 1 A UTG lamination component for a folding screen, which sequentially includes, from top to bottom: a functional base film layer, a first thermoplastic polymer layer, an ultra-thin glass layer, and a second thermoplastic polymer layer. The thickness of the functional base film is 30 μm; the thickness of the first thermoplastic polymer layer is 20 μm; the thickness of the ultra-thin glass layer is 30 μm; the thickness of the second thermoplastic polymer layer is 20 μm.

[0041] The first thermoplastic polymer layer and the second thermoplastic polymer layer are cured and made from the same thermoplastic polymer composition. The raw materials of the thermoplastic polymer composition include 4 kg of thermoplastic polyurethane elastomer, 2 kg of polycarbonate, and 0.1 kg of nano boron nitride.

[0042] The raw material components and dosages of the functional base film layer are shown in Table 1, wherein the modified black phosphorus quantum dots are the modified black phosphorus quantum dots prepared in Preparation Example 1; the grafted microcrystalline cellulose is the grafted microcrystalline cellulose prepared in Preparation Example 5; the promoter is benzyl dimethylamine; the ultraviolet absorber is thiospiropyran.

[0043] A preparation method of a UTG lamination component for a folding screen includes the following steps: S1. Prepare the functional base film layer: Mix polyimide resin, polyarylether nitrile, gas-phase nano-silica, poly(pentafluoropropyl methacrylate), modified black phosphorus quantum dots, grafted microcrystalline cellulose, promoter, ultraviolet absorber, and solvent, and stir at a speed of 500 r / min at 70 °C for 4 h to fully mix and form a base film coating. The solvent is N,N-dimethylacetamide, and the solvent dosage is 30 kg. Then, coat the base film coating on a polyester release film by a casting method, with a film thickness of 25 μm, and then transfer it to a vacuum oven at 80 °C for drying for 3 h. After complete curing, cool it to room temperature and peel it off from the release film to obtain the functional base film layer; S2. Prepare the thermoplastic polymer layer: Mix thermoplastic polyurethane elastomer, polycarbonate, and nano boron nitride to obtain a thermoplastic polymer composition, and then melt and co-extrude it through a twin-screw extruder at 190 °C to make a sheet with a thickness of 20 μm, and then perform shearing to obtain the first thermoplastic polymer layer and the second thermoplastic polymer layer respectively; S3. Assemble the lamination component: Stack the functional base film layer, the first thermoplastic polymer layer, the ultra-thin glass layer, and the second thermoplastic polymer layer in sequence, put the stacked four-layer material into a vacuum hot press, and hot press it at 110 °C and a pressure of 1.5 MPa for 25 min. After the hot pressing is completed, wait for the temperature to cool to obtain a UTG lamination component for a folding screen.

[0044] Example 2 A UTG laminated component for a folding screen includes, from top to bottom, a functional base film layer, a first thermoplastic polymer layer, an ultra-thin glass layer, and a second thermoplastic polymer layer. The thickness of the functional base film is 30 μm; the thickness of the first thermoplastic polymer layer is 30 μm; the thickness of the ultra-thin glass layer is 30 μm; and the thickness of the second thermoplastic polymer layer is 30 μm.

[0045] The first thermoplastic polymer layer and the second thermoplastic polymer layer are made by curing the same thermoplastic polymer composition. The raw materials of the thermoplastic polymer composition include 5kg of thermoplastic polyurethane elastomer, 2.5kg of polycarbonate and 0.2kg of nano boron nitride.

[0046] The raw material components and dosages of the functional base film layer are shown in Table 1, wherein the modified black phosphorus quantum dots are selected from the modified black phosphorus quantum dots prepared in Preparation Example 1; the grafted microcrystalline cellulose is selected from the grafted microcrystalline cellulose prepared in Preparation Example 5; the promoter is benzyldimethylamine; and the ultraviolet absorber is thiospiropyran.

[0047] A method for preparing a UTG laminated component for a folding screen comprises the following steps: S1. Preparation of functional base film layer: polyimide resin, polyarylether nitrile, fumed nano-silica, polymethacrylate pentafluoropropyl, modified black phosphorus quantum dots, grafted microcrystalline cellulose, promoter, ultraviolet absorber and solvent are mixed, stirred at 70°C at a speed of 500r / min for 4h, and fully mixed to form a base film coating, wherein the solvent is N,N-dimethylacetamide, and the amount of solvent is 33kg. Then the base film coating is coated on the polyester release film by casting method, with a film thickness of 30μm, and then transferred to a vacuum oven at 100°C for drying for 2h, cooled to room temperature after complete curing, and peeled off from the release film to obtain a functional base film layer; S2, preparing a thermoplastic polymer layer: mixing a thermoplastic polyurethane elastomer, polycarbonate and nano boron nitride to obtain a thermoplastic polymer composition, and then melt-blending and extruding the mixture at 195° C. through a twin-screw extruder to form a sheet with a thickness of 30 μm, and then shearing the sheet to obtain a first thermoplastic polymer layer and a second thermoplastic polymer layer, respectively; S3. Assemble the laminated components: stack the functional base film layer, the first thermoplastic polymer layer, the ultra-thin glass layer and the second thermoplastic polymer layer in sequence, put the stacked four layers of materials into a vacuum hot press, and hot press them at 120°C and 2.0MPa pressure for 20 minutes. After the hot pressing is completed, wait for the temperature to cool down to obtain the UTG laminated component for the folding screen.

[0048] Example 3 A UTG lamination component for a folding screen, which sequentially includes, from top to bottom: a functional base film layer, a first thermoplastic polymer layer, an ultra-thin glass layer, and a second thermoplastic polymer layer. The thickness of the functional base film is 40 μm; the thickness of the first thermoplastic polymer layer is 35 μm; the thickness of the ultra-thin glass layer is 30 μm; the thickness of the second thermoplastic polymer layer is 35 μm.

[0049] The first thermoplastic polymer layer and the second thermoplastic polymer layer are cured from the same thermoplastic polymer composition. The raw materials of the thermoplastic polymer composition include 6 kg of thermoplastic polyurethane elastomer, 3 kg of polycarbonate, and 0.3 kg of nano boron nitride.

[0050] The raw material components and dosages of the functional base film layer are shown in Table 1, in which the modified black phosphorus quantum dots are the modified black phosphorus quantum dots prepared in Preparation Example 1; the grafted microcrystalline cellulose is the grafted microcrystalline cellulose obtained in Preparation Example 5; the promoter is benzyl dimethylamine; the ultraviolet absorber is thiospiropyran.

[0051] A preparation method of a UTG lamination component for a folding screen includes the following steps: S1. Prepare the functional base film layer: Mix polyimide resin, polyarylether nitrile, gas-phase nano-silica, poly(pentafluoropropyl methacrylate), modified black phosphorus quantum dots, grafted microcrystalline cellulose, promoter, ultraviolet absorber, and solvent, and stir at a speed of 500 r / min at 70 °C for 4 h to fully mix and form a base film coating. The solvent is N,N-dimethylacetamide, and the solvent dosage is 33 kg. Then, coat the base film coating on a polyester release film by a casting method, with a film thickness of 40 μm, and then transfer it to a vacuum oven at 120 °C for drying for 1 h. After complete curing, cool it to room temperature and peel it off from the release film to obtain the functional base film layer; S2. Prepare the thermoplastic polymer layer: Mix thermoplastic polyurethane elastomer, polycarbonate, and nano boron nitride to obtain a thermoplastic polymer composition, and then melt and co-extrude it through a twin-screw extruder at 200 °C to form a sheet with a thickness of 35 μm, and then perform shearing to obtain the first thermoplastic polymer layer and the second thermoplastic polymer layer respectively; S3. Assemble the lamination component: Stack the functional base film layer, the first thermoplastic polymer layer, the ultra-thin glass layer, and the second thermoplastic polymer layer in sequence, put the stacked four-layer material into a vacuum hot press, and hot press it at 130 °C and a pressure of 2.5 MPa for 15 min. After the hot pressing is completed, wait for the temperature to cool to obtain a UTG lamination component for a folding screen.

[0052] Table 1 Raw material components and dosages (kg) of the functional base film layer in Examples 1-3

[0053] Example 4 A UTG lamination component for a folding screen, which is different from that in Example 1 in that in this example, the modified black phosphorus quantum dots are the modified black phosphorus quantum dots prepared in Preparation Example 2; the grafted microcrystalline cellulose is the grafted microcrystalline cellulose obtained in Preparation Example 6.

[0054] Example 5 A UTG lamination component for a folding screen, which is different from that in Example 1 in that in this example, the modified black phosphorus quantum dots are the modified black phosphorus quantum dots prepared in Preparation Example 3; the grafted microcrystalline cellulose is the grafted microcrystalline cellulose obtained in Preparation Example 7.

[0055] Example 6 A UTG lamination component for a folding screen, which is different from that in Example 1 in that in this example, the modified black phosphorus quantum dots are the modified black phosphorus quantum dots prepared in Preparation Example 4.

[0056] Example 7 A UTG lamination component for a folding screen, which is different from that in Example 1 in that in this example, the grafted microcrystalline cellulose is the grafted microcrystalline cellulose obtained in Preparation Example 8.

[0057] Example 8 A UTG lamination component for a folding screen, which is different from that in Example 1 in that in this example, the ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone.

[0058] Comparative Example Comparative Example 1 A glass cover plate for a folding screen, which sequentially includes from top to bottom: a PET film layer, an OCA optical adhesive layer, an ultra-thin glass layer, an OCA optical adhesive layer, and a POP film layer.

[0059] A preparation method of a glass cover plate for a folding screen is as follows: cleaning the PET film layer and the POP film layer with deionized water to remove surface dust and impurities; cleaning the ultra-thin glass with deionized water and then drying it; taking an appropriate amount of OCA optical adhesive and coating it on one side of the PET film, both sides of the ultra-thin glass, and one side of the POP layer respectively, fitting the coated surface of the PET film to one side of the ultra-thin glass, and fitting the coated surface of the POP layer to the other side of the ultra-thin glass, and performing hot pressing and lamination. The hot pressing temperature is 60 °C, and the pressure is 0.2 MPa to discharge air bubbles, so that each layer is tightly combined to obtain a glass cover plate for a folding screen.

[0060] Comparative Example 2 A UTG lamination component for a folding screen, which is different from that in Example 1 in that in this comparative example, modified black phosphorus quantum dots and grafted microcrystalline cellulose are not added to the functional base film raw materials, and the difference is supplemented with polyimide resin.

[0061] Comparative Example 3 A UTG lamination component for a folding screen, which is different from that in Example 1. In this comparative example, unmodified black phosphorus quantum dots are used instead of modified black phosphorus quantum dots in the raw material of the functional base film.

[0062] Comparative Example 4 A UTG lamination component for a folding screen, which is different from that in Example 1. In this comparative example, ungrafted microcrystalline cellulose is used instead of grafted microcrystalline cellulose in the raw material of the functional base film.

[0063] Performance detection test Detection object: The lamination components prepared in Examples 1-8 and Comparative Examples 1-4.

[0064] Detection content: 1. Impact resistance detection Place the glass cover plate horizontally on the fixing device, select one with a diameter of 20 mm and a mass of 32.6 g, and let it fall freely from different heights to impact the surface of the glass cover plate. Observe the surface damage of the glass cover plate after impact, such as whether there are cracks, breakages, chipping, etc. Record the critical height at which the glass cover plate begins to show damage under impacts at different heights, and evaluate its impact resistance based on this.

[0065] 2. Hardness detection Scratch the surface of the glass cover plate with standard minerals of different hardnesses, and observe the scratch situation on the surface of the glass cover plate to determine its Mohs hardness grade. The Mohs hardness is divided into 10 grades, from 1 (talc) to 10 (diamond). The higher the grade, the higher the hardness of the glass cover plate.

[0066] 3. Transmittance detection Use an ultraviolet-visible spectrophotometer, place the UTG lamination component in the optical path, and measure the transmittance in the specific wavelength ranges of 500 nm, 600 nm, and 700 nm. The result is the average value.

[0067] Detection results: See Table 2.

[0068] Table 2 Detection results

[0069] The anti-impact critical height of Examples 1-5 is between 1930-2000 mm, indicating that the UTG laminated component for foldable screens prepared in this application has good anti-impact performance. This is because the modified black phosphorus quantum dots in the functional base film layer and other components act synergistically to effectively disperse and absorb impact energy when subjected to impact; the grafted microcrystalline cellulose forms a reinforcing network structure in the base film, which also helps to improve the overall anti-impact performance; at the same time, the thermoplastic polyurethane elastomer in the thermoplastic polymer layer gives the material flexibility, the polycarbonate provides strength and rigidity, and the nano boron nitride further enhances the hardness and wear resistance. Each layer collaborates to protect the ultra-thin glass layer and improve the anti-impact ability of the component.

[0070] The anti-impact critical height of Comparative Example 1 is only 980 mm. Because it adopts the structure of "PET-OCA-UTG-OCA-POP", the OCA adhesive layer has a low modulus and cannot effectively disperse the impact energy, and the protective effects of the PET film and the POP film are limited. In Comparative Example 2, the modified black phosphorus quantum dots and the grafted microcrystalline cellulose were not added, and the anti-impact critical height was 1300 mm, lower than that of Example 1, indicating that these two substances play an important role in improving the anti-impact performance. In Comparative Example 3, unmodified black phosphorus quantum dots were used, and in Comparative Example 4, ungrafted microcrystalline cellulose was used. Their anti-impact performance was also inferior to that of the examples, further proving the necessity of modification and grafting treatment for enhancing the anti-impact performance.

[0071] The hardness grades of Examples 1-8 are all 6, indicating relatively high hardness. This is because the polyimide resin and polyarylether nitrile in the functional base film layer provide the basic strength and stability framework, and nano-silica, modified black phosphorus quantum dots, grafted microcrystalline cellulose, etc. further increase the hardness; the polycarbonate and nano boron nitride in the thermoplastic polymer layer also help to enhance the hardness. The two thermoplastic polymer layers and the functional base film layer act synergistically to jointly improve the hardness of the entire cover plate material.

[0072] The hardness grade of Comparative Example 1 is 3, which is relatively low, mainly because the OCA adhesive layer has a low modulus and the PET film and the POP film do not have high hardness. The hardness grades of Comparative Examples 2-4 are 4-5, lower than those of the examples, indicating that the modified black phosphorus quantum dots and the grafted microcrystalline cellulose play a significant role in increasing the hardness. The modification and grafting treatment enable them to better cooperate with other components in the base film and enhance the hardness of the base film.

[0073] The light transmittance of Examples 1-5 ranges from 96.0% to 96.9%, having a relatively high light transmittance. This is because after the modified black phosphorus quantum dots are modified by the zinc-based metal-organic framework material, their high porosity and uniform pore size distribution reduce the light scattering in the base film. At the same time, the interaction with other components in the base film is optimized, which can regulate the light absorption and transmission. The grafted microcrystalline cellulose makes the interior of the base film more dense and uniform, reduces the hindrance of light propagation, and lowers the reflection and scattering. In addition, the laminated component of this application adopts a four-layer structure and is directly hot-pressed into shape without an OCA adhesive layer, reducing the interface reflection loss, thereby improving the overall light transmittance, and enabling the folding screen to have a good appearance and visual experience.

[0074] The light transmittance of Comparative Example 1 is 83.1%, which is relatively low because the presence of the OCA adhesive layer, PET film, and POP film increases the interface reflection loss, and the light transmittance of the PET film and POP film themselves is lower than that of UTG. In Comparative Example 2, the modified black phosphorus quantum dots and grafted microcrystalline cellulose are not added, and the light transmittance is 84.2%, indicating that the modified black phosphorus quantum dots and grafted microcrystalline cellulose play a significant role in improving the light transmittance. In Comparative Example 3, unmodified black phosphorus quantum dots are used, and in Comparative Example 4, ungrafted microcrystalline cellulose is used. Their light transmittances are 87.2% and 89.6% respectively, both lower than those of the examples. Further, the modification and grafting treatment of black phosphorus quantum dots and microcrystalline cellulose respectively play a key role in optimizing the light scattering, absorption, and transmission and improving the light transmittance.

[0075] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A UTG laminated assembly for a folding screen, characterized in that: It includes, from top to bottom: a functional base film layer, a first thermoplastic polymer layer, an ultra-thin glass layer and a second thermoplastic polymer layer; The first thermoplastic polymer layer and the second thermoplastic polymer layer are made by curing the same thermoplastic polymer composition, wherein the thermoplastic polymer composition is made of the following raw materials by weight: 40-60 parts of thermoplastic polyurethane elastomer, 20-30 parts of polycarbonate, and 1-3 parts of nano boron nitride; The functional base film layer is made of the following raw materials by weight: 60-85 parts of polyimide resin, 20-30 parts of polyarylether nitrile, 5-15 parts of fumed nano-silica, 3-8 parts of polymethacrylate pentafluoropropyl, 3-7 parts of modified black phosphorus quantum dots, 2-5 parts of grafted microcrystalline cellulose, 1-3 parts of accelerator, and 1-3 parts of ultraviolet absorber; The grafted microcrystalline cellulose is obtained by grafting polymethyl methacrylate on microcrystalline cellulose; The modified black phosphorus quantum dots are obtained by modifying black phosphorus quantum dots with zinc-based metal organic framework materials.

2. The UTG laminate assembly for a folding screen according to claim 1, characterized in that: The modified black phosphorus quantum dots are prepared by the following method: A. Mix zinc nitrate, 2-methylimidazole and N,N-dimethylformamide, stir and react at a speed of 500-700 r / min for 30-50 min, and then react at 100-120° C. for 20-24 h. After the reaction, centrifuge the reaction product, wash and dry the reaction product to obtain ZIF-8 powder; B. Mix the ZIF-8 powder with the black phosphorus quantum dot dispersion, perform ultrasonic treatment for 1-2 hours, and then stir the mixture at 30-40°C and 200-300 r / min for 20-24 hours. After the reaction, centrifuge the product, wash and dry the reaction product to obtain modified black phosphorus quantum dots.

3. A UTG laminate assembly for a folding screen according to claim 2, characterized in that: In step A, the mass ratio of zinc nitrate, 2-methylimidazole and N,N-dimethylformamide is 1:(2-3):(20-30).

4. The UTG laminate assembly for a folding screen according to claim 2, characterized in that: The mass concentration of the black phosphorus quantum dot dispersion in step B is 25%-30%; the mass ratio of the ZIF-8 powder to the black phosphorus quantum dot dispersion is 1:(1-3).

5. The UTG laminate assembly for a folding screen according to claim 1, characterized in that: The grafted microcrystalline cellulose is prepared by the following method: (1) Add microcrystalline cellulose to a NaOH solution, stir at 60-80°C and 200-400 r / min for 10-12 hours, filter and then wash with an ethanol-water mixture until the pH of the filtrate is 7-8 to obtain surface hydroxyl-activated cellulose; (2) Add surface hydroxyl-activated cellulose, methyl methacrylate, azobisisobutyronitrile and dimethyl sulfoxide into a reaction vessel, and stir the reaction at 60-70°C and 300-400 r / min for 8-12 hours under nitrogen protection; after the reaction, pour the reaction product into anhydrous ethanol for precipitation, filter and wash with anhydrous ethanol for 3-5 times, and finally vacuum dry at 50-60°C for 12-24 hours to obtain grafted microcrystalline cellulose.

6. The UTG laminate assembly for a folding screen according to claim 5, characterized in that: The mass concentration of the NaOH solution in step (1) is 5%-10%, and the mass ratio of the microcrystalline cellulose to the NaOH solution is 1:(10-15).

7. The UTG laminate assembly for a folding screen according to claim 5, characterized in that: The mass ratio of the surface hydroxyl activated cellulose, methyl methacrylate, azobisisobutyronitrile and dimethyl sulfoxide in step (2) is (1-2): (3-4): (0.05-0.1):

15.

8. The UTG laminate assembly for a folding screen according to claim 1, characterized in that: The ultraviolet absorber is thiospiropyran.

9. A method for preparing a UTG laminate assembly for a folding screen as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Preparing a functional base film layer: uniformly mixing polyimide resin, polyarylether nitrile, fumed nano-silica, polypentafluoropropyl methacrylate, modified black phosphorus quantum dots, grafted microcrystalline cellulose, an accelerator, an ultraviolet absorber and a solvent to obtain a base film coating, coating the base film coating on a polyester release film, and after drying and curing, peeling the base film from the polyester release film to obtain a functional base film layer; S2, preparing a thermoplastic polymer layer: mixing a thermoplastic polyurethane elastomer, polycarbonate and nano boron nitride to obtain a thermoplastic polymer composition, and then melt-blending and extruding the mixture at 190-200° C. through a twin-screw extruder to form a sheet, and then shearing the mixture to obtain a first thermoplastic polymer layer and a second thermoplastic polymer layer, respectively; S3. Assemble the laminated components: stack the functional base film layer, the first thermoplastic polymer layer, the ultra-thin glass layer and the second thermoplastic polymer layer in sequence, put the stacked four layers of materials into a vacuum hot press, and hot press them at 110-130°C and 1.5-2.5MPa pressure for 15-25 minutes. After the hot pressing is completed, wait for the temperature to cool down to obtain the UTG laminated component for the folding screen.

10. The method for preparing a UTG laminate assembly for a folding screen according to claim 9, characterized in that: The drying and curing in S1 is performed at a temperature of 80-120° C. and a drying and curing time of 1-3 hours.

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