Optical film based on PMMA / PTFS blending material, preparation method of optical film and liquid crystal display equipment

Abstract

The invention discloses an optical film based on a PMMA / PTFS blending material, a preparation method of the optical film and liquid crystal display equipment, the preparation method of the optical film based on the PMMA / PTFS blending material comprises the steps of substrate cleaning, blending solution preparation, coating film forming, staged drying and subsequent processing, and the optical film based on the PMMA / PTFS blending material is prepared by optimizing the mass ratio of PTFS / PMMA (such as 10 / 90, 20 / 80, 30 / 70 and the like) and combining a tetrahydrofuran / butanone cosolvent system. The balance between optical properties (such as high light transmittance and controllable delay value) and mechanical properties (such as high tensile strength and dimensional stability) of the film is realized, and addition of a proper amount of PTFS not only maintains high light transmittance, but also significantly improves in-plane delay value regulation and control capability and heat resistance and moisture resistance of the film material. According to the optimized preparation process, a solution coating technology is adopted, and a semi-closed drying process and stretching treatment are combined, so that the optical uniformity and smoothness of the membrane material are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical functional film manufacturing, and particularly to an optical film based on a PMMA / PTFS blend material, a preparation method thereof, and a liquid crystal display device. Background Art

[0002] A polarizer is an essential optical component in a liquid crystal display device, and one of its core components is a protective film and a compensation film; triacetyl cellulose (TAC) film is widely used in polarizers because it has high light transmittance, low birefringence, good moisture resistance and thermal stability. However, the TAC film has obvious deficiencies. Its rigid molecular chain structure makes it weak in mechanical properties, especially in terms of tensile strength and toughness. In addition, the negative birefringence characteristic of the TAC film has limited ability to regulate the retardation value, and it is difficult to meet the requirements of high-resolution and extra-large-size liquid crystal display devices for high phase retardation values and optical uniformity; at the same time, the processing technology of the TAC film is complex, and a large amount of plasticizers and ultraviolet absorbers usually need to be added to improve its moisture permeability and processability, which further increases the manufacturing cost.

[0003] In contrast, polymethyl methacrylate (PMMA) film is considered a potential material to replace the TAC film because of its excellent optical and mechanical properties. The light transmittance of the PMMA film in the visible light band is as high as 92%, and it has a similar low negative birefringence characteristic to the TAC film; in addition, the PMMA film is significantly superior to the TAC film in terms of tensile strength and tensile strength, making it more advantageous in terms of dimensional stability and mechanical durability. However, the PMMA film also has significant limitations. Its heat resistance and toughness are both inferior to the TAC film, and it is prone to deformation especially in a high-temperature environment, thus affecting the optical and mechanical stability of the film. At the same time, the PMMA film has limited ability to regulate the retardation value and is difficult to meet the requirements of high-resolution liquid crystal display devices for viewing angle compensation. Summary of the Invention

[0004] The main object of the present invention is to provide a preparation method of an optical film based on a PMMA / PTFS blend material, aiming to solve the problems of poor optical and mechanical stability of the PMMA film and difficulty in meeting the requirements of high-resolution liquid crystal display devices for viewing angle compensation.

[0005] To achieve the above object, the present invention proposes a preparation method of an optical film based on a PMMA / PTFS blend material, and the preparation method of the optical film based on a PMMA / PTFS blend material includes: S1. Clean a float soda-lime flat glass substrate material with a thickness of 3 mm successively with 10% dilute sulfuric acid, deionized water, acetone and isopropanol, perform ultrasonic treatment for 5 minutes, and then dry it with an electric hair dryer; S2. Weigh PTFS and PMMA according to the mass ratio range of PTFS / PMMA from 10 / 90 to 70 / 30. After mixing them evenly, add a co-solvent of tetrahydrofuran / butanone with an equal mass ratio to prepare a blend solution with a solute content of 10%, 15% or 20% in the total mass of the solution. Seal it and place it on a shaker, and oscillate at room temperature for 48 hours until the solution is completely homogeneous. S3. Pour 5 ml of the blend solution onto the surface of a cleaned glass substrate, and use a coating knife to evenly coat a film within a rectangular range of 30 mm × 100 mm. S4. Surround the wet film after coating with glass strips to form a semi-closed cavity, and place it in a horizontally calibrated oven. Dry it at 60 °C for 24 hours, and then raise the temperature to 90 °C and continue baking for 12 hours. S5. Peel the dried film from the substrate, cut it into a spline of 30 mm × 80 mm, and then put it into a vacuum oven at 60 °C for storage for later use.

[0006] The present invention also provides an optical film based on a PMMA / PTFS blend material, and the optical film based on the PMMA / PTFS blend material is obtained by the preparation method of the optical film based on the PMMA / PTFS blend material as described above.

[0007] The present invention also provides a liquid crystal display device, and the liquid crystal display device includes the optical film based on the PMMA / PTFS blend material as described above.

[0008] The technical solution of the present invention realizes the uniform film formation of the PVA film and the regulation of the polarization characteristics by adopting common solution coating methods and orientation stretching techniques. The overall preparation process is simplified, reducing the production difficulty and time cost; the prepared blend film uses PMMA as the matrix and combines the high optical performance of PTFS, showing high light transmittance and controllable retardation value, and can meet the requirements of the polarizing film in optical compensation. The transparency and optical uniformity of the blend film are significantly better than those of traditional TAC films, and are suitable for high-resolution and large-size liquid crystal display devices; the blend film of the present invention has excellent tensile strength and toughness through the synergistic effect of PMMA and PTFS, and can still maintain shape stability in high-temperature and high-humidity environments, avoiding the performance degradation of traditional films under extreme conditions. This excellent dimensional stability and mechanical durability ensure the long-term use reliability of the film material. Description of the Drawings

[0009] Figure 1 It is a schematic structural formula diagram of PTFS in the preparation method of the optical film based on the PMMA / PTFS blend material of the present invention. Figure 2Schematic diagram of the transmittance of PTFS / PMMA (50 / 50) for the preparation method of the optical film based on PMMA / PTFS blend materials of the present invention in the near ultraviolet-visible light band; Figure 3 Schematic diagram of the in-plane retardation values (normalized to thickness) of thin films with different blend ratios of the preparation method of the optical film based on PMMA / PTFS blend materials of the present invention at different draw ratios. Detailed implementation manners

[0010] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0011] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0012] It should be noted that: similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0013] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0014] In addition, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0015] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and defined, terms such as "arrangement" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0016] The present invention provides a method for preparing an optical film based on a PMMA / PTFS blend material. The following will describe the specific embodiments of the present invention in detail with reference to the accompanying drawings.

[0017] As Figures 1-3 shown, the method for preparing an optical film based on a PMMA / PTFS blend material includes the following steps: S1. Clean a float soda-lime flat glass substrate material with a thickness of 3 mm successively with 10% dilute sulfuric acid, deionized water, acetone, and isopropanol, perform ultrasonic treatment for 5 minutes, and then dry it with an electric hair dryer. S2. Weigh PTFS and PMMA according to the mass ratio range of PTFS / PMMA being 10 / 90 to 70 / 30, mix them evenly, add a co-solvent of tetrahydrofuran / butanone with an equal mass ratio, and prepare a blend solution with a solute content of 10%, 15%, or 20% in the total mass of the solution. Seal it and place it on a shaker, and oscillate it at room temperature for 48 hours until the solution is completely homogeneous. S3. Pour 5 ml of the blend solution onto the surface of the cleaned glass substrate, and evenly coat it into a film within a rectangular range of 30 mm × 100 mm with a coating knife. S4. Surround the wet film after coating with glass strips to form a semi-closed cavity, and place it in a horizontally calibrated oven. Dry it at 60 °C for 24 hours, and then raise the temperature to 90 °C and continue baking for 12 hours. S5. Peel the dried film from the substrate, cut it into a spline of 30 mm × 80 mm, and then place it in a vacuum oven at 60 °C for storage for later use.

[0018] In one embodiment, the co-solvent further includes a mixed solvent of tetrahydrofuran / toluene or tetrahydrofuran / cyclopentanone.

[0019] In one embodiment, the height range of the coating knife is 500 μm to 1000 μm, and the coating speed range of the coating knife is 3 mm / s to 8 mm / s.

[0020] In one embodiment, the in-plane retardation value of the film reaches 300 - 800 nm after stretching.

[0021] The preparation method of the optical film based on PMMA / PTFS blend material develops a new type of polarizer protective film and compensation film with both high optical performance and excellent mechanical properties by introducing polytetrafluorostyrene (PTFS) and blending it with PMMA, and adopting solution coating and stretching treatment technologies. By optimizing the co-solvent system (such as equal proportion mixing of THF / MEK) and controlling processing parameters, while maintaining high light transmittance and good retardation value regulation ability of the film, the heat resistance and elongation at break are significantly improved. In addition, by stretching treatment to improve the orientation structure of molecular chains, the retardation value performance of the film is further enhanced. This method provides a feasible solution for the application of acrylic resin-based films in high-performance polarizers, reduces the manufacturing cost at the same time, and promotes the further development of liquid crystal display technology.

[0022] The present invention also provides an optical film based on PMMA / PTFS blend material, which is obtained by the preparation method of the optical film based on PMMA / PTFS blend material described above; the specific steps of the preparation method of the optical film based on PMMA / PTFS blend material refer to the above embodiments. Since the optical film based on PMMA / PTFS blend material adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0023] The present invention also provides a liquid crystal display device, which includes the optical film based on PMMA / PTFS blend material as described above.

[0024] Example 1 (control group) S1. Clean the substrate material. Use 3-mm-thick float soda-lime plate glass as the substrate material. After rinsing the surface of the glass plate with 10% dilute sulfuric acid and deionized water in sequence, dry the water stains with lint-free paper, then ultrasonically clean with acetone, isopropanol and deionized water for 5 minutes in sequence, and finally dry with an electric hair dryer. S2. Weigh a certain mass of PMMA, add tetrahydrofuran / butanone with equal mass ratio as the co-solvent according to 15% of the total mass of the mixed solution, seal it and place it on a shaker, and oscillate at room temperature for 48 h to make it fully dissolve. S3. Take 5 ml of the mixed solution and pour it evenly within a 30×100 mm rectangular range on the glass substrate. Place a wet film former with a coating height of 1000 μm on the side of the solution away from the coating direction. Set the blade height to 1000 μm, the coating speed to 5 mm / s, and the coating stroke to 300 mm. S4. After coating, surround a rectangle with 6-mm-thick glass strips around the wet film, and then cover it with a glass plate to form a semi-closed cavity. S5. Place the flat glass in an oven calibrated to be level with a spirit level, dry it at 60 °C for 24 h, then raise the temperature to 90 °C and continue baking for 12 h. S6. Cool to room temperature, peel off the blend film, cut it into several 30×80 mm strips, and finally store it in a vacuum oven at 60 °C for later use.

[0025] Example 2. The preparation method steps are as follows: S1. Clean the substrate material. Use 3-mm-thick float soda-lime flat glass as the substrate material. After rinsing the glass plate surface with 10% dilute sulfuric acid and deionized water in sequence, dry the water stains with lint-free paper, then ultrasonically clean it with acetone, isopropanol, and deionized water for 5 min each in sequence, and finally dry it with an electric hair dryer. S2. Weigh PTFS and PMMA according to the mass ratio of PTFS / PMMA = 10 / 90, and add a tetrahydrofuran / butanone mixture with an equal mass ratio as the co-solvent according to 15% of the total mass of the mixed solution. Seal it and place it on a shaker, and oscillate it at room temperature for 48 h to fully dissolve it. S3. Take 5 ml of the mixed solution and evenly pour it within a 30×100 mm rectangular range on the glass substrate. Place a wet film applicator with a coating height of 1000 μm on the side far from the coating direction. Set the blade height to 1000 μm, the coating speed to 5 mm / s, and the coating stroke to 300 mm. S4. After coating, surround a rectangle with 6-mm-thick glass strips around the wet film, and then cover it with a glass plate to form a semi-closed cavity. S5. Place the flat glass in an oven calibrated to be level with a spirit level, dry it at 60 °C for 24 h, then raise the temperature to 90 °C and continue baking for 12 h. S6. Cool to room temperature, peel off the blend film, cut it into several 30×80 mm strips, and finally store it in a vacuum oven at 60 °C for later use.

[0026] Example 3. The preparation method steps are as follows: S1. Clean the substrate material. Use 3-mm-thick float soda-lime flat glass as the substrate material. After rinsing the glass plate surface with 10% dilute sulfuric acid and deionized water in sequence, dry the water stains with lint-free paper, then ultrasonically clean it with acetone, isopropanol, and deionized water for 5 min each in sequence, and finally dry it with an electric hair dryer. S2. Weigh PTFS and PMMA according to the mass ratio of PTFS / PMMA = 20 / 80, and add a tetrahydrofuran / butanone mixture with an equal mass ratio as the co-solvent according to 15% of the total mass of the mixed solution. Seal it and place it on a shaker, and oscillate it at room temperature for 48 h to fully dissolve it. S3. Take 5 ml of the mixed solution and evenly pour it within a 30×100 mm rectangular range on the glass substrate. Place a wet film applicator with a coating height of 1000 μm on the side of the solution away from the coating direction. Set the blade height of the wet film applicator to 1000 μm, the coating speed to 5 mm / s, and the coating stroke to 300 mm; S4. After coating, use a 6 mm thick glass strip to enclose a rectangle around the wet film, and then cover it with a glass plate to form a semi-closed cavity; S5. Place the flat glass in an oven calibrated to be level with a spirit level, dry it at 60 °C for 24 h, and then raise the temperature to 90 °C and continue baking for 12 h; S6. Cool to room temperature, peel off the blend film, cut it into several 30×80 mm strips, and finally store them in a vacuum oven at 60 °C for standby.

[0027] Example 4. The preparation method steps are as follows: S1. Clean the substrate material. Use a 3 mm thick float soda-lime flat glass as the substrate material. After rinsing the surface of the glass plate with 10% dilute sulfuric acid and deionized water in sequence, dry the water stains with lint-free paper, then ultrasonically clean it with acetone, isopropanol, and deionized water for 5 min each in sequence, and finally dry it with an electric hair dryer; S2. Weigh PTFS and PMMA according to the mass ratio of PTFS / PMMA = 30 / 70, and add a tetrahydrofuran / butanone mixture with an equal mass ratio as the co-solvent according to 15% of the total mass of the mixed solution. Seal it and place it on a shaker, and oscillate it at room temperature for 48 h to fully dissolve it; S3. Take 5 ml of the mixed solution and evenly pour it within a 30×100 mm rectangular range on the glass substrate. Place a wet film applicator with a coating height of 1000 μm on the side of the solution away from the coating direction. Set the blade height of the wet film applicator to 1000 μm, the coating speed to 5 mm / s, and the coating stroke to 300 mm; S4. After coating, use a 6 mm thick glass strip to enclose a rectangle around the wet film, and then cover it with a glass plate to form a semi-closed cavity; S5. Place the flat glass in an oven calibrated to be level with a spirit level, dry it at 60 °C for 24 h, and then raise the temperature to 90 °C and continue baking for 12 h; S6. Cool to room temperature, peel off the blend film, cut it into several 30×80 mm strips, and finally store them in a vacuum oven at 60 °C for standby.

[0028] Example 5. The preparation method steps are as follows: S1. Clean the substrate material. Use 3-mm-thick float soda-lime plate glass as the substrate material. After rinsing the surface of the glass plate successively with 10% dilute sulfuric acid and deionized water, dry the water stains with lint-free paper, then ultrasonically clean it successively with acetone, isopropanol, and deionized water for 5 min each, and finally dry it with an electric hair dryer; S2. Weigh PTFS and PMMA according to the mass ratio of PTFS / PMMA = 40 / 60, and add a tetrahydrofuran / butanone mixture with an equal mass ratio as the co-solvent according to 15% of the total mass of the mixed solution. Seal it and place it on a shaker, and oscillate it at room temperature for 48 h to fully dissolve it; S3. Take 5 ml of the mixed solution and evenly pour it within a 30×100-mm rectangular range on the glass substrate. Place a wet film applicator with a coating height of 1000 μm on the side away from the coating direction. Set the blade height to 1000 μm, the coating speed to 5 mm / s, and the coating stroke to 300 mm; S4. After coating, surround the wet film with 6-mm-thick glass strips to form a rectangle, and then cover it with a glass plate to form a semi-closed cavity; S5. Place the flat glass in an oven calibrated to be horizontal by a spirit level, dry it at 60 °C for 24 h, and then raise the temperature to 90 °C and continue baking for 12 h; S6. Cool to room temperature, peel off the blend film, cut it into several 30×80-mm strips, and finally store it in a vacuum oven at 60 °C for standby.

[0029] Example 6. The preparation method steps are as follows: S1. Clean the substrate material. Use 3-mm-thick float soda-lime plate glass as the substrate material. After rinsing the surface of the glass plate successively with 10% dilute sulfuric acid and deionized water, dry the water stains with lint-free paper, then ultrasonically clean it successively with acetone, isopropanol, and deionized water for 5 min each, and finally dry it with an electric hair dryer; S2. Weigh PTFS and PMMA according to the mass ratio of PTFS / PMMA = 50 / 50, and add a tetrahydrofuran / butanone mixture with an equal mass ratio as the co-solvent according to 15% of the total mass of the mixed solution. Seal it and place it on a shaker, and oscillate it at room temperature for 48 h to fully dissolve it; S3. Take 5 ml of the mixed solution and evenly pour it within a 30×100-mm rectangular range on the glass substrate. Place a wet film applicator with a coating height of 1000 μm on the side away from the coating direction. Set the blade height to 1000 μm, the coating speed to 5 mm / s, and the coating stroke to 300 mm; S4. After coating, surround the wet film with 6-mm-thick glass strips to form a rectangle, and then cover it with a glass plate to form a semi-closed cavity; S5. Place the flat glass in an oven calibrated to be level with a spirit level, dry it at 60 °C for 24 h, then raise the temperature to 90 °C and continue baking for 12 h; S6. Cool to room temperature, peel off the blend film, cut it into several 30×80 mm strips, and finally store it in a vacuum oven at 60 °C for later use.

[0030] Example 7. The preparation method steps are as follows: S1. Clean the substrate material. Use 3 mm thick float soda-lime flat glass as the substrate material. After rinsing the glass plate surface with 10% dilute sulfuric acid and deionized water in sequence, dry the water stains with lint-free paper, then ultrasonically clean it with acetone, isopropyl alcohol, and deionized water for 5 min in sequence, and finally dry it with an electric hair dryer; S2. Weigh PTFS and PMMA according to the mass ratio of PTFS / PMMA = 60 / 40, and add a tetrahydrofuran / butanone mixture with an equal mass ratio as the co-solvent according to 15% of the total mass of the mixed solution. Seal it and place it on a shaker, and oscillate it at room temperature for 48 h to fully dissolve it; S3. Take 5 ml of the mixed solution and pour it evenly within a 30×100 mm rectangle on the glass substrate. Place a wet film applicator with a coating height of 1000 μm on the side far from the coating direction. Set the blade height to 1000 μm, the coating speed to 5 mm / s, and the coating stroke to 300 mm; S4. After coating, surround a rectangle with 6 mm thick glass strips around the wet film, and then cover it with a glass plate to form a semi-closed cavity; S5. Place the flat glass in an oven calibrated to be level with a spirit level, dry it at 60 °C for 24 h, then raise the temperature to 90 °C and continue baking for 12 h; S6. Cool to room temperature, peel off the blend film, cut it into several 30×80 mm strips, and finally store it in a vacuum oven at 60 °C for later use.

[0031] Example 8. The preparation method steps are as follows: S1. Clean the substrate material. Use 3 mm thick float soda-lime flat glass as the substrate material. After rinsing the glass plate surface with 10% dilute sulfuric acid and deionized water in sequence, dry the water stains with lint-free paper, then ultrasonically clean it with acetone, isopropyl alcohol, and deionized water for 5 min in sequence, and finally dry it with an electric hair dryer; S2. Weigh PTFS and PMMA according to the mass ratio of PTFS / PMMA = 70 / 30, and add a tetrahydrofuran / butanone mixture with an equal mass ratio as the co-solvent according to 15% of the total mass of the mixed solution. Seal it and place it on a shaker, and oscillate it at room temperature for 48 h to fully dissolve it; S3. Pour 5 ml of the mixed solution evenly within a 30×100 mm rectangular area on the glass substrate. Place a wet film coater with a coating height of 1000 μm on the side of the solution away from the coating direction. Set the blade height to 1000 μm, the coating speed to 5 mm / s, and the coating stroke to 300 mm. S4. After coating, use a 6-mm thick glass strip to enclose a rectangle around the wet film, and then cover it with a glass plate to form a semi-closed cavity. S5. Place the flat glass in an oven calibrated to be horizontal by a spirit level. Dry it at 60 °C for 24 h, and then raise the temperature to 90 °C and continue baking for 12 h. S6. Cool to room temperature, peel off the blend film, cut it into several 30×80 mm strips, and finally store them in a vacuum oven at 60 °C for standby.

[0032] It can be seen from Figure 2 that the transmittance of the PTFS / PMMA (50 / 50) blend film in the visible light band (wavelength 400 nm - 750 nm) exceeds 92%, showing very excellent light transparency. This indicates that the mixing of PMMA and PTFS has no obvious effect on the transparency of the PMMA film. The lowest light transmittance in the visible light band is still 91%, which is beneficial to reducing the light intensity loss in the display optical path and improving the display brightness.

[0033] The phase retardation value of the film is the most important characteristic of the compensation film. The specific retardation value needs to be designed according to the requirements of the display. Usually, an in-plane retardation value of 300 - 800 nm is required. Figure 3 shows the variation law of the in-plane retardation values of films with different blend ratios after being treated with different stretching ratios. Before stretching, the in-plane retardation values of different blend components are all zero, and the slope of the fitted straight line is zero, indicating that the film before stretching treatment is isotropic in the in-plane direction, with zero birefringence and no change with the component. After stretching, the in-plane retardation value of the film increases with the increase of the stretching ratio, and the higher the content of PTFS, the greater the contribution to the increase of the in-plane retardation value. It is thus speculated that the stretching process promotes the molecular chain orientation of PTFS in the blend.

[0034] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principles of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing an optical film based on a PMMA / PTFS blend material, characterized in that, The preparation method of the optical film based on the PMMA / PTFS blend material comprises the following steps: S1. The float soda-lime flat glass substrate material with a thickness of 3 mm is successively cleaned with 10% dilute sulfuric acid, deionized water, acetone and isopropanol, ultrasonically treated for 5 minutes, and then dried with an electric hair dryer; S2. According to the mass ratio range of PTFS / PMMA being 10 / 90 to 70 / 30, PTFS and PMMA are weighed and mixed evenly, and then a co-solvent of tetrahydrofuran / butanone with an equal mass ratio is added to prepare a blend solution with a solute content of 10%, 15% or 20% in the total mass of the solution. After sealing, it is placed on a shaker and oscillated at room temperature for 48 hours until the solution is completely uniform; S3. 5 ml of the blend solution is poured onto the surface of the cleaned glass substrate, and a film is evenly coated within a rectangular range of 30 mm×100 mm with a coating knife; S4. The periphery of the wet film after coating is surrounded by glass strips to form a semi-closed cavity, and it is placed in a horizontally calibrated oven, dried at 60 °C for 24 hours, and then heated to 90 °C and baked for another 12 hours; S5. The dried film is peeled off from the substrate, cut into a sample strip of 30 mm×80 mm, and then placed in a vacuum oven at 60 °C for storage for later use.

2. The preparation method of the optical film based on the PMMA / PTFS blend material according to claim 1, wherein The co-solvent also includes a mixed solvent of tetrahydrofuran / toluene or tetrahydrofuran / cyclopentanone.

3. The preparation method of the optical film based on the PMMA / PTFS blend material according to claim 1, wherein, The height range of the coating knife is 500 μm to 1000 μm, and the coating speed range of the coating knife is 3 mm / s to 8 mm / s.

4. The preparation method of the optical film based on the PMMA / PTFS blend material according to claim 1, wherein The in-plane retardation value of the film reaches 300 - 800 nm after stretching.

5. An optical film based on PMMA / PTFS blend material, characterized in that, The optical film based on the PMMA / PTFS blend material is obtained by the preparation method of the optical film based on the PMMA / PTFS blend material according to any one of claims 1 - 4.

6. A liquid crystal display device, characterized in that, The liquid crystal display device includes the optical film based on the PMMA / PTFS blend material as described in claim 5.

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