High-temperature-resistant display screen protective film and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant display screen protective film and a preparation method thereof, and belongs to the technical field of preparation of display screen protective films. The high-temperature-resistant display screen protective film comprises a base material layer and a modified BiVO4 film layer, a preparation method of the modified BiVO4 film layer comprises the following steps: S1, dispersing Bi (NO3) 3.5 H2O, NH4VO3 and citric acid in an acetic acid / N, N-dimethylformamide solution, and heating and stirring for 2-3 hours to obtain a mixed solution; s2, adding C2H7NO, a silane coupling agent and an acetic acid / N, N-dimethylformamide solution into the mixed solution, and heating and stirring for 22-24 hours to obtain a coating solution; and S3, coating a carrier with the coating liquid, drying at high temperature, annealing, cooling to room temperature, and separating from the carrier to obtain the modified BiVO4 film layer. The preparation method provided by the invention is simple and easy to implement, low in raw material price, eco-friendly, chemically stable and suitable for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of display screen protective film preparation, and in particular relates to a high-temperature resistant display screen protective film and a preparation method thereof. Background Art

[0002] With the development of technology, touch-screen products such as mobile phones, tablet computers, and optical touch screens have become indispensable items in people's lives. In order to prevent the touch screen from being scratched or abraded by nails or other hard objects, most consumers will stick a layer of inexpensive and high-quality protective film on the touch screen.

[0003] The materials used for display screen protective films are constantly evolving, evolving from the original PC (polycarbonate) films, PVC (polyvinyl chloride) films, and PET (polyethylene terephthalate) films to the current mainstream tempered glass films, TPU films, and all-adhesive composite films. Patent application number CN109401653 A discloses a high-temperature-resistant, low-elution protective film and its applications. The film comprises, from top to bottom, a release layer, an adhesive layer, and a substrate layer. The adhesive layer is an acetic acid pressure-sensitive adhesive, which includes an acetic acid copolymer, ethyl acetate, a curing agent, a high-temperature-resistant filler, and a low-elution additive. The protective film exhibits excellent high-temperature resistance. After being bonded to glass, it can withstand temperatures of 220°C in a vacuum environment without bulging or wrinkling. Upon removal, there is no white fog or adhesive residue.

[0004] To enhance the user experience and protect vision, display screen protective films are expanding beyond simple drop and shock protection. A growing number of films are now offering optical protection, such as high transmittance, anti-glare, and blue light protection. However, these films still suffer from wear and tear resistance and are prone to scratching, which increases eye strain, causes eye fatigue, and impairs vision. Display screen protective films should evolve from simply providing anti-glare and fingerprint resistance to offering multifunctional optical features, including anti-glare, display anti-reflection, blue light protection, fingerprint resistance, and high and low temperature resistance. Summary of the Invention

[0005] The object of the present invention is to provide a high-temperature resistant display screen protective film and a preparation method thereof, so as to improve the high-temperature resistance of the display screen protective film.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A high-temperature resistant display screen protective film, comprising a substrate layer and a modified BiVO4 film layer;

[0008] The preparation method of the modified BiVO4 film is as follows:

[0009] S1. Disperse Bi(NO3)3·5H2O, NH4VO3 and citric acid in acetic acid / N,N-dimethylformamide solution, heat and stir for 2-3 h to obtain a mixed solution;

[0010] S2. Add C2H7NO, silane coupling agent and acetic acid / N,N-dimethylformamide solution to the mixed solution, heat and stir for 22-24 hours to obtain a coating solution;

[0011] S3. The coating liquid is coated on the carrier, dried at high temperature, annealed, cooled to room temperature, and separated from the carrier to obtain a modified BiVO4 film layer.

[0012] Furthermore, the mass fraction of acetic acid in the acetic acid / N,N-dimethylformamide solution is 10%-40%.

[0013] Furthermore, the molar ratio of Bi(NO3)3·5H2O, NH4VO3 and citric acid is (0.5-2):(0.5-2):(3-6).

[0014] Furthermore, the temperature of the heating and stirring is 40-50°C.

[0015] Furthermore, the mass ratio of Bi(NO3)3·5H2O, C2H7NO and silane coupling agent is (1-1.2):(0.1-0.3):(0.01-0.1).

[0016] Furthermore, the silane coupling agent is one or a combination of perfluorodecyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 4-anilinotriethoxysilane, 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

[0017] Furthermore, the coating method is a spin coating method.

[0018] Furthermore, the carrier is glass.

[0019] Furthermore, the high temperature drying is drying at a temperature of 140-150° C. for 0.5-1 h.

[0020] Furthermore, the annealing is performed at 450-500° C. for 15-30 minutes.

[0021] A method for preparing a high-temperature resistant display screen protective film comprises the following steps:

[0022] The modified BiVO4 film layer is attached to the substrate layer and heated and cured to obtain a high-temperature resistant display screen protective film.

[0023] Furthermore, the substrate layer is one of polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate.

[0024] Furthermore, the thickness of the modified BiVO4 film layer is 25-75 μm, and the thickness of the substrate film is 100-150 μm.

[0025] Beneficial effects of the present invention:

[0026] (1) The present invention provides a high-temperature resistant display screen protective film, comprising a substrate layer and a modified BiVO4 film layer; the substrate layer provides good mechanical properties, and the modified BiVO4 film layer can enhance the heat resistance and mechanical properties of the material after being attached and combined with the substrate layer. In addition, the BiVO4 film layer also has blue light shielding capability, which expands the functionality of the protective film.

[0027] (2) The modified BiVO4 film layer used in the present invention is modified by a silane coupling agent, which not only improves the dispersibility of BiVO4 particles, but the groups of the coupling agent can also improve the functionality of the protective film (for example, perfluorodecyltrimethoxysilane can improve flame retardancy and hydrophobicity); and BiVO4 not only has a good blue light protection effect, but also can improve the heat resistance of the protective film.

[0028] (3) The BiVO4 film synthesis method employed in the present invention is to prepare BiVO4 directly in solution by spin coating followed by high-temperature drying and annealing. Compared to synthesizing BiVO4 particles first and then dissolving them in a solvent, the one-step BiVO4 film formation provides better dispersion, further enhancing the performance of the protective film. Furthermore, the preparation method provided by the present invention utilizes inexpensive, eco-friendly, and chemically stable raw materials suitable for large-scale production. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] Example 1

[0031] This embodiment provides a method for preparing a high-temperature resistant display screen protective film, which is prepared by the following steps:

[0032] S1. Disperse 4.85 g of Bi(NO3)3·5H2O, 1.17 g of NH4VO3, and 7.68 g of citric acid in 80 mL of a 20% by mass acetic acid / N,N-dimethylformamide solution, and heat and stir at 45°C for 2.5 h to obtain a mixed solution;

[0033] S2. Add 0.97 g of C2H7NO, 0.24 g of perfluorodecyltrimethoxysilane, and 30 mL of a 20% by mass acetic acid / N,N-dimethylformamide solution to the mixture, and heat and stir at 45° C. for 24 h to obtain a coating solution.

[0034] S3. The coating liquid is applied on glass by a spin coating method, dried at a temperature of 145°C for 0.5 h, annealed at 500°C for 15 min, cooled to room temperature and separated from the carrier to obtain a modified BiVO4 film layer; the modified BiVO4 film layer is attached to a polyethylene naphthalate substrate layer (the thickness of the modified BiVO4 film layer is 50 μm, and the thickness of the substrate film is 125 μm), heated and cured to obtain a high-temperature resistant display screen protective film.

[0035] Example 2

[0036] Compared with Example 1, this embodiment differs in that the molar ratio of Bi(NO3)3·5H2O, NH4VO3 and citric acid is changed to 2:2:3. The specific implementation steps of S1 are as follows:

[0037] S1. Disperse 9.7 g of Bi(NO3)3·5H2O, 2.34 g of NH4VO3, and 5.76 g of citric acid in 100 mL of a 20% by mass acetic acid / N,N-dimethylformamide solution, and heat and stir at 45°C for 2.5 h to obtain a mixed solution.

[0038] The remaining raw materials and preparation process remain the same as in Example 1.

[0039] Example 3

[0040] Compared with Example 1, this embodiment differs in that the molar ratio of Bi(NO3)3·5H2O, NH4VO3 and citric acid is changed to 0.5:0.5:6. The specific implementation steps of S1 are as follows:

[0041] S1. Disperse 2.43 g of Bi(NO3)3·5H2O, 0.59 g of NH4VO3, and 11.52 g of citric acid in 80 mL of a 20% by mass acetic acid / N,N-dimethylformamide solution, and heat and stir at 45°C for 2.5 h to obtain a mixed solution;

[0042] The remaining raw materials and preparation process remain the same as in Example 1.

[0043] Example 4

[0044] Compared with Example 1, this embodiment differs in that the mass ratio of Bi(NO3)3·5H2O, C2H7NO and silane coupling agent is changed to 1:0.3:0.1. The specific implementation steps of S2 are as follows:

[0045] S2. Add 1.46 g of C2H7NO, 0.49 g of perfluorodecyltrimethoxysilane, and 30 mL of a 20% by mass acetic acid / N,N-dimethylformamide solution to the mixture, and heat and stir at 45° C. for 24 h to obtain a coating solution.

[0046] The remaining raw materials and preparation process remain the same as in Example 1.

[0047] Example 5

[0048] Compared with Example 1, this embodiment differs in that the mass ratio of Bi(NO3)3·5H2O, C2H7NO and silane coupling agent is changed to 1:0.1:0.01. The specific implementation steps of S2 are as follows:

[0049] S2. Add 0.49 g of C2H7NO, 0.049 g of perfluorodecyltrimethoxysilane, and 30 mL of a 20% by mass acetic acid / N,N-dimethylformamide solution to the mixture, and heat and stir at 45° C. for 24 h to obtain a coating solution.

[0050] The remaining raw materials and preparation process remain the same as in Example 1.

[0051] Example 6

[0052] Compared with Example 1, this embodiment differs in that the silane coupling agent is replaced with 3-aminopropyltrimethoxysilane. The specific implementation steps of S2 are as follows:

[0053] S2. Add 0.97 g of C2H7NO, 0.24 g of 3-aminopropyltrimethoxysilane, and 30 mL of a 20% by mass acetic acid / N,N-dimethylformamide solution to the mixture, and heat and stir at 45° C. for 24 h to obtain a coating solution.

[0054] The remaining raw materials and preparation process remain the same as in Example 1.

[0055] Example 7

[0056] Compared with Example 1, this embodiment differs in that the thickness of the modified BiVO4 film layer and the substrate film are changed. The specific implementation steps of S3 are as follows:

[0057] S3. The coating liquid is applied on glass by a spin coating method, dried at a temperature of 145°C for 0.5 h, annealed at 500°C for 15 min, cooled to room temperature and separated from the carrier to obtain a modified BiVO4 film layer; the modified BiVO4 film layer is attached to a polyethylene naphthalate substrate layer (the thickness of the modified BiVO4 film layer is 25 μm, and the thickness of the substrate film is 150 μm), heated and cured to obtain a high-temperature resistant display screen protective film.

[0058] The remaining raw materials and preparation process remain the same as in Example 1.

[0059] Example 8

[0060] Compared with Example 1, this embodiment differs in that the thickness of the modified BiVO4 film layer and the substrate film are changed. The specific implementation steps of S3 are as follows:

[0061] S3. The coating liquid is applied on glass by a spin coating method, dried at a temperature of 145°C for 0.5h, annealed at 500°C for 15min, cooled to room temperature and separated from the carrier to obtain a modified BiVO4 film layer; the modified BiVO4 film layer is attached to a polyethylene naphthalate substrate layer (the thickness of the modified BiVO4 film layer is 75μm, and the thickness of the substrate film is 100μm), heated and cured to obtain a high-temperature resistant display screen protective film.

[0062] The remaining raw materials and preparation process remain the same as in Example 1.

[0063] Comparative Example 1

[0064] Compared with Example 1, this comparative example differs in that no C2H7NO is added. The specific implementation steps are as follows:

[0065] S1. Disperse 4.85 g of Bi(NO3)3·5H2O, 1.17 g of NH4VO3, and 7.68 g of citric acid in 80 mL of a 20% by mass acetic acid / N,N-dimethylformamide solution, and heat and stir at 45°C for 2.5 h to obtain a mixed solution;

[0066] S2. Add 0.24 g of perfluorodecyltrimethoxysilane and 30 mL of 20% by mass acetic acid / N,N-dimethylformamide solution to the mixed solution, and heat and stir at 45° C. for 24 h to obtain a coating solution;

[0067] S3. The coating liquid is applied on glass by a spin coating method, dried at a temperature of 145°C for 0.5 h, annealed at 500°C for 15 min, cooled to room temperature and separated from the carrier to obtain a modified BiVO4 film layer; the modified BiVO4 film layer is attached to a polyethylene naphthalate substrate layer (the thickness of the modified BiVO4 film layer is 50 μm, and the thickness of the substrate film is 125 μm), heated and cured to obtain a high-temperature resistant display screen protective film.

[0068] The remaining raw materials and preparation process remain the same as in Example 1.

[0069] Comparative Example 2

[0070] Compared with Example 1, this comparative example differs in that no silane coupling agent is added. The specific implementation steps are as follows:

[0071] S1. Disperse 4.85 g of Bi(NO3)3·5H2O, 1.17 g of NH4VO3, and 7.68 g of citric acid in 80 mL of a 20% by mass acetic acid / N,N-dimethylformamide solution, and heat and stir at 45°C for 2.5 h to obtain a mixed solution;

[0072] S2. Add 0.97 g of C2H7NO and 30 mL of 20% acetic acid / N,N-dimethylformamide solution to the mixture, and heat and stir at 45°C for 24 h to obtain a coating solution;

[0073] S3. The coating liquid is applied on glass by a spin coating method, dried at a temperature of 145°C for 0.5 h, annealed at 500°C for 15 min, cooled to room temperature and separated from the carrier to obtain a modified BiVO4 film layer; the modified BiVO4 film layer is attached to a polyethylene naphthalate substrate layer (the thickness of the modified BiVO4 film layer is 50 μm, and the thickness of the substrate film is 125 μm), heated and cured to obtain a high-temperature resistant display screen protective film.

[0074] The remaining raw materials and preparation process remain the same as in Example 1.

[0075] Comparative Example 3

[0076] Compared with Example 1, this comparative example differs in that neither C2H7NO nor silane coupling agent is added. The specific implementation steps are as follows:

[0077] S1. Disperse 4.85 g of Bi(NO3)3·5H2O, 1.17 g of NH4VO3, and 7.68 g of citric acid in 80 mL of a 20% by mass acetic acid / N,N-dimethylformamide solution, and heat and stir at 45°C for 2.5 h to obtain a mixed solution;

[0078] S2. Add 30 mL of 20% acetic acid / N,N-dimethylformamide solution to the mixed solution, heat and stir at 45° C. for 24 h to obtain a coating solution;

[0079] S3. The coating liquid is applied on glass by a spin coating method, dried at a temperature of 145°C for 0.5 h, annealed at 500°C for 15 min, cooled to room temperature and separated from the carrier to obtain a modified BiVO4 film layer; the modified BiVO4 film layer is attached to a polyethylene naphthalate substrate layer (the thickness of the modified BiVO4 film layer is 50 μm, and the thickness of the substrate film is 125 μm), heated and cured to obtain a high-temperature resistant display screen protective film.

[0080] The remaining raw materials and preparation process remain the same as in Example 1.

[0081] Comparative Example 4

[0082] S1. Disperse 4.85 g of Bi(NO3)3·5H2O, 1.17 g of NH4VO3, and 7.68 g of citric acid in 80 mL of a 20% by mass acetic acid / N,N-dimethylformamide solution, and heat and stir at 45°C for 2.5 h to obtain a mixed solution; add 0.97 g of C2H7NO to the mixed solution, heat and stir for 22-24 h, centrifuge, wash, and dry to obtain BiVO4;

[0083] S2. Disperse 2.5 g of BiVO4 and 0.24 g of perfluorodecyltrimethoxysilane in 30 mL of a 20% by mass acetic acid / N,N-dimethylformamide solution, add the solution to the mixture, mix well, and heat with stirring at 45° C. for 24 h to obtain a coating solution;

[0084] S3. The coating liquid is applied on glass by a spin coating method, dried at a temperature of 145°C for 0.5 h, annealed at 500°C for 15 min, cooled to room temperature and separated from the carrier to obtain a modified BiVO4 film layer; the modified BiVO4 film layer is attached to a polyethylene naphthalate substrate layer (the thickness of the modified BiVO4 film layer is 50 μm, and the thickness of the substrate film is 125 μm), heated and cured to obtain a high-temperature resistant display screen protective film.

[0085] The remaining raw materials and preparation process remain the same as in Example 1.

[0086] Comparative Example 5

[0087] This comparative example is a single substrate film.

[0088] Performance tests were performed on Examples 1 to 8 and Comparative Examples 1 to 5.

[0089] Light transmittance: According to GB T 2410-2008 "Determination of light transmittance and haze of transparent plastics", the light transmittance of the high-temperature resistant display screen protective films obtained in various examples and comparative examples of this application was tested;

[0090] Blue light blocking rate: The blue light blocking rate of the high temperature resistant display screen protective films obtained in each embodiment and comparative example of the present application was tested using an optical transmittance meter;

[0091] (High temperature treatment: Place at 90°C and 80% humidity for 200 hours)

[0092] The results are shown in Table 1:

[0093] Table 1

[0094]

[0095]

[0096] According to the examples, comparative examples and the data in Table 1, it can be seen that the only difference between Examples 2-5 and Example 1 is that the raw material ratio of the modified BiVO4 film layer is changed within a reasonable range during the preparation process. From the results in Table 1, the prepared high-temperature resistant display screen protective films all have good light transmittance, blue light blocking rate and heat resistance; compared with Example 1, the performance of the prepared high-temperature resistant display screen protective film in Example 6 is reduced, which may be because perfluorodecyltrimethoxysilane has better hydrophobicity, so that it can maintain its original performance in a high temperature and high humidity environment; compared with Example 1, the difference between Examples 7-8 lies in the thickness ratio of the modified BiVO4 film layer and the substrate film. In actual production and use, it is necessary to select an appropriate thickness according to actual conditions to make a balanced choice between light transmittance and blue light blocking rate.

[0097] Compared with Example 1, in Comparative Example 1, the blue light blocking rate of the protective film decreases after no addition of C2H7NO. This is because C2H7NO is a strong base, which acts as a catalyst in the system and promotes the formation of BiVO4. Compared with Example 1, in Comparative Example 2, the blue light blocking rate and heat resistance decrease after no addition of silane coupling agent. This is because the dispersibility of BiVO4 decreases. Compared with Comparative Example 3 and Comparative Examples 1-2 and Example 1, the heat resistance and blue light blocking rate of the protective film decrease significantly after no addition of C2H7NO and silane coupling agent, which fully demonstrates the role of both in the synthesis and dispersion of modified BiVO4. Compared with Example 1, the difference between Comparative Example 4 and Example 1 lies in the optimization of the synthesis process. After repeated experiments to determine the appropriate molar ratio, the BiVO4 synthesis and drying steps are omitted, and the next step of coating is directly entered, avoiding the problem of BiVO4 particle size leading to a decrease in protective film performance. Compared with Example 1, Comparative Example 5 is equivalent to the blank control.

[0098] In summary, the present invention provides a high-temperature resistant display screen protective film and a preparation method thereof. The prepared protective film has good light transmittance, blue light blocking rate and heat resistance. The provided preparation method is simple and easy, the raw materials are low-priced, eco-friendly, chemically stable, and suitable for large-scale production.

[0099] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0100] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A high temperature resistant display screen protective film, characterized in that: It includes a substrate layer and a modified BiVO4 film layer; The modified BiVO4 film is prepared by the following steps: S1. Disperse Bi(NO3)3·5H2O, NH4VO3 and citric acid in acetic acid / N,N-dimethylformamide solution, heat and stir for 2-3 h to obtain a mixed solution; S2. Add C2H7NO, silane coupling agent and acetic acid / N,N-dimethylformamide solution to the mixed solution, heat and stir for 22-24 hours to obtain a coating solution; S3. The coating liquid is coated on the carrier, dried at high temperature, annealed, cooled to room temperature, and separated from the carrier to obtain a modified BiVO4 film layer.

2. The high temperature resistant display screen protective film according to claim 1, characterized in that: The mass fraction of acetic acid in the acetic acid / N,N-dimethylformamide solution is 10%-40%.

3. The high temperature resistant display screen protective film according to claim 1, characterized in that: The molar ratio of Bi(NO3)3·5H2O, NH4VO3 and citric acid is (0.5-2):(0.5-2):(3-6).

4. The high temperature resistant display screen protective film according to claim 1, characterized in that: The mass ratio of Bi(NO3)3·5H2O, C2H7NO and silane coupling agent is (1-1.2):(0.1-0.3):(0.01-0.1).

5. The high temperature resistant display screen protective film according to claim 1, characterized in that: The silane coupling agent is one or a combination of perfluorodecyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 4-anilinotriethoxysilane, 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

6. The high temperature resistant display screen protective film according to claim 1, characterized in that: The coating method is a spin coating method; the carrier is glass.

7. The high temperature resistant display screen protective film according to claim 1, characterized in that: The heating and stirring temperature is 40-50° C.; the high-temperature drying is drying at a temperature of 140-150° C. for 0.5-1 h; and the annealing is annealing at 450-500° C. for 15-30 min.

8. A method for preparing a high temperature resistant display screen protective film according to any one of claims 1 to 7, characterized in that: The following steps are involved: The modified BiVO4 film layer is attached to the substrate layer and heated and cured to obtain a high-temperature resistant display screen protective film.

9. The method for preparing a high-temperature resistant display screen protective film according to claim 8, characterized in that: The substrate layer is one of polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate.

10. The method for preparing a high temperature resistant display screen protective film according to claim 8, characterized in that: The thickness of the modified BiVO4 film layer is 25-75 μm, and the thickness of the substrate film is 100-150 μm.

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