A highly durable anti-blue light optical film and method of making the same
By introducing a multi-layer structure and a specific particle combination into the optical film, the problem of balancing blue light blocking and transparency was solved, achieving high durability and blue light protection, while improving the film's haze and light transmittance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-19
- Publication Date
- 2026-06-16
AI Technical Summary
Existing optical diffusion films cannot effectively block blue light, leading to increased eye strain and difficulty in achieving both transparency and haze.
A composite structure consisting of a PET substrate layer, a first diffusion layer, and a second diffusion layer is adopted. By adding sodium isophthalate-5-sulfonate and hindered amine light stabilizers to the PET substrate layer, the first diffusion layer uses porous PS microspheres and nano-SiO2 particles, and the second diffusion layer uses PMMA-CeO2-SiO2 hybrid particles and blue light absorbers, multi-layer light scattering and blue light absorption are achieved.
It improves the durability and transparency of the optical film, while effectively blocking blue light in the 380-450nm range, reducing eye damage, enhancing the film's haze and light transmittance, and improving its UV resistance and abrasion resistance.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of optical film technology, specifically to a high-durability blue light blocking optical film and its preparation method. Background Technology
[0002] PET optical films, due to their colorless transparency, gloss, good mechanical properties, and high hardness and toughness, are widely used in downstream markets such as liquid crystal displays (LCDs) and organic light-emitting diode (OLED) displays, in applications such as diffusion films and diffusion films. Diffuse films, also known as separation films, transform point light sources into uniform surface light sources through scattering, refraction, and reflection. Diffuse film products come in various thicknesses and widths and are used in LCDs, LED backlighting, and other fields. They are also used in educational hardware; for example, some learning machines employ multi-layer diffusion film technology to achieve a more uniform light distribution on the screen.
[0003] However, ordinary optical diffusion films only diffuse light, offering no protection against blue light emitted from electronic screens or light sources. Short-wavelength blue light has extremely high energy, capable of penetrating the lens and reaching the retina. Blue light scattering exacerbates the eye's accommodative burden, easily leading to eye strain, blurred vision, and other harmful effects. Currently, research on blue light blocking diffusion films is relatively limited within the broader field of optical films. Therefore, obtaining a diffusion film that blocks blue light while maintaining high haze and high light transmittance is a pressing problem that needs to be solved in this field. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a high-durability blue light blocking optical film and its preparation method.
[0005] To achieve the above objectives, the present invention provides the following technical solution: A high-durability blue light blocking optical film, comprising: The PET substrate layer is made by melt extrusion of optical-grade PET chips, sodium isophthalate-5-sulfonate, hindered amine light stabilizers and antioxidants; The first diffusion layer is obtained by coating a first coating liquid, including epoxy acrylic resin and first diffusion particles, onto a PET substrate layer and curing it. The second diffusion layer is obtained by coating a PET substrate layer with a second coating liquid comprising an organic-inorganic hybrid UV curable resin, second diffusion particles, and a blue light absorber and curing it. The preparation process of the first diffused particle is as follows: firstly, PS seed microspheres are prepared by dispersion polymerization, then porous microspheres are prepared by swelling polymerization, and finally, nano-silica particles are deposited on its surface to obtain the particle. The preparation process of the second diffused particles is as follows: Cerium oxide is treated with a double-bonded silane coupling agent and then dispersed and polymerized with methyl methacrylate to obtain microspheres. These microspheres are then placed in an aqueous solution of PDADMAC (polydiallyl dimethyl ammonium chloride) to adsorb and obtain hybrid particles with positively charged surfaces. Finally, these particles are obtained by electrostatic self-assembly adsorption with an aqueous dispersion of SiO2. The organic-inorganic hybrid UV-curable resin is a silica sol-modified acrylate resin.
[0006] Further, the PET substrate layer, by weight, comprises 100 parts optical-grade PET chips, 2-5 parts sodium isophthalate-5-sulfonate, 0.1-0.5 parts hindered amine light stabilizer, and 0.1-0.5 parts antioxidant; the hindered amine light stabilizer is TH-944; and the antioxidant is Irganox 1010.
[0007] Further, the first coating liquid, by weight, comprises 100 parts epoxy acrylate resin, 5-15 parts first diffusion particles, 1-5 parts DPHA (dipentaerythritol hexaacrylate), 10-30 parts IBOA (isobornyl acrylate), and 1-3 parts TPO; the dry film thickness is 5-12 μm.
[0008] Furthermore, the preparation process of the first diffusing particle is as follows: S1-1. Add ethanol / deionized water mixed solvent to the reaction flask, add polyvinylpyrrolidone and stir evenly, heat to 70℃, add styrene monomer and AIBN initiator, and polymerize under nitrogen protection for 12h. Centrifuge the obtained product, wash with ethanol and dry to obtain seed microspheres, disperse them in polyvinylpyrrolidone aqueous solution and stir evenly for later use. S1-2. Add toluene, styrene, benzoyl peroxide and divinylbenzene to the reaction flask and stir until they are evenly mixed. Emulsify evenly in an aqueous solution containing sodium dodecyl sulfate. Slowly add to the seed microsphere dispersion and stir at room temperature to swell for 12-24 h. Heat to 70℃ and polymerize for 24 h. Centrifuge to collect the microspheres. S1-3. The collected microspheres are redispersed in a mixed solvent of ethanol / deionized water. Tetraethyl orthosilicate and ammonia are added. The mixture is stirred at room temperature to allow the SiO2 generated by the hydrolysis of tetraethyl orthosilicate to be deposited on the surface of the microspheres and the inner wall of the pores. The microspheres are then separated by centrifugation and extracted to obtain the final product.
[0009] Furthermore, the preparation process of the first diffusing particle is as follows: S1-1. Add 100 mL of a 1:1 mixture of ethanol and deionized water to a reaction flask, add 1.2 g of polyvinylpyrrolidone and stir until homogeneous. Heat to 70 °C, add 10-20 g of styrene monomer and 0.05-0.2 g of AIBN initiator, and polymerize under nitrogen protection for 12 h. Centrifuge the obtained product, wash with ethanol and dry to obtain seed microspheres; take 10 g and disperse in 400 mL of an aqueous solution containing 1 wt% PVA, stir until homogeneous and set aside. S1-2. Add 20-30g toluene, 40-50g styrene, 1-3g benzoyl peroxide and 2-4g divinylbenzene to a reaction flask and stir until they are evenly mixed. Then emulsify in 100mL of 0.2wt% sodium dodecyl sulfonate aqueous solution, and then dropwise add to the seed microsphere dispersion. Stir and swell at room temperature for 12-24h, raise the temperature to 70℃, and polymerize under nitrogen protection for 24h. Collect the microspheres by centrifugation and dry at low temperature. S1-3. The collected microspheres (5g) were redispersed in 100 mL of a 1:1 mixture of ethanol and deionized water, 5 mL of tetraethyl orthosilicate and 1 mL of ammonia were added, and the mixture was stirred at room temperature for 6-8 h. After centrifugation and washing with water, the microspheres were placed in a Soxhlet extractor and extracted with anhydrous ethanol. After vacuum drying at 50 °C, porous core-shell composite microspheres, i.e., the first diffusion particles, were obtained.
[0010] Further, the second coating liquid, by weight fraction, comprises 10-20 parts of organic-inorganic hybrid UV-curable resin, 30-50 parts of reactive diluent, 20-40 parts of acrylate oligomer, 10-25 parts of second diffusion particles, 1-4 parts of blue light absorber, 1-3 parts of TPO, 0.1-0.5 parts of leveling agent, and 0.1-0.5 parts of defoamer; the dry film thickness is 8-12 μm. Preferably, the acrylate oligomer is an epoxy acrylate oligomer or a polyurethane acrylate oligomer.
[0011] Furthermore, the preparation process of the second diffused particle is as follows: S2-1. The silane coupling agent containing double bonds is placed in a mixed solvent of water and ethanol for hydrolysis. Cerium oxide is dispersed in anhydrous ethanol and then added dropwise to the hydrolysis solution of the silane coupling agent to obtain modified cerium oxide. S2-2. Modified cerium oxide was dispersed in a water / ethanol mixed solvent, polyvinylpyrrolidone, methyl methacrylate and initiator AIBN were added, nitrogen gas was introduced to remove oxygen from the system, the temperature was raised to 60-70℃ and the reaction was carried out for 24 hours. The product was centrifuged, washed with ethanol and dried to obtain PMMA microspheres. S2-3. Disperse PMMA microspheres in 0.2wt% PDADMAC aqueous solution, stir at room temperature for 60-120 min, centrifuge, wash with water and dry to obtain positively charged hybrid particles; take nano-SiO2 and ultrasonically disperse in deionized water, adjust the pH to 7.5-8.0 with ammonia water, ultrasonically disperse for 30 min to obtain a stable dispersion with a solid content of 1wt%. S2-4. The positively charged hybrid particles are redispersed in deionized water and added dropwise to the stable dispersion while stirring. The mass ratio of SiO2 to hybrid particles is 1:10~15. After the addition is complete, continue stirring at room temperature for 1 hour, centrifuge, wash with water, and then dry under low temperature vacuum.
[0012] Furthermore, the silane coupling agent containing double bonds is preferably one of γ-methacryloyloxypropyltrimethoxysilane (KH570), methyl vinyldimethoxysilane, and vinyltris(2-methoxyethoxy)silane (A-172).
[0013] Furthermore, the organic-inorganic hybrid UV-curable resin is a NANOCRYL® series nano silica acrylate dispersion, preferably, the organic-inorganic hybrid UV-curable resin is NANOCRYL® C140 or NANOCRYL® C130.
[0014] Furthermore, the blue light absorber is one or more of blue light absorber 46, blue light absorber 47, blue light absorber 93, or blue light absorber 605.
[0015] A second objective of this invention is to provide a method for preparing a high-durability blue light blocking optical film according to any one of the preceding claims, comprising the following steps: 1) The PET substrate layer raw material is dried, blended, and then fed into a twin-screw extruder for melt extrusion to form a cast sheet; 2) The cast sheet is biaxially stretched, cooled and shaped to obtain a film with a total thickness of 50~70 μm, and then corona treated; 3) Mix the first coating liquid evenly according to the formula, and then coat it onto the film surface by slit coating, followed by UV curing; 4) Prepare the second coating liquid. Weigh each raw material according to the formula, premix the oligomer, reactive diluent, photoinitiator, leveling agent and defoamer, add organic-inorganic hybrid UV curing resin, stir and grind thoroughly, finally add the second diffusion particles and blue light absorber, degas under vacuum, and then coat the other side of the film by slit coating and UV curing to obtain the coating liquid.
[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. Sodium isophthalate-5-sulfonate, hindered amine light stabilizer, and antioxidant are added to the PET substrate layer, which improves the surface activity and polarity of the substrate and gives the PET substrate long-lasting resistance to UV yellowing. 2. The first diffusion layer is made of porous PS microspheres combined with nano-SiO2 deposition. The porous structure provides high light scattering efficiency, and the deposited nano-SiO2 improves the surface hardness and compatibility of the particles. It can improve haze with a low addition amount and reduce the negative impact on light transmittance. 3. The second diffusion layer comprises silica sol-modified acrylate resin, second diffusion particles composed of PMMA-CeO2-SiO2, and a blue light absorber. The silica sol-modified acrylate resin has excellent wear resistance and scratch resistance, good UV resistance, and does not affect transparency. The second diffusion particles, with PMMA-encapsulated CeO2 as the core, also have diffusion and scattering capabilities, as well as high wear resistance and light absorption. They are combined with SiO2 through electrostatic self-assembly, further enhancing the stability of the particles. The synergistic effect of the blue light absorber enables the film to suppress light with wavelengths of 380~450 nm, greatly reducing the harm of blue light to the eyes. Detailed Implementation
[0017] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0019] Example: A high-durability blue light blocking optical film, comprising: The PET substrate layer is prepared by melt extrusion of 100 parts optical-grade PET chips, 2-5 parts sodium isophthalate-5-sulfonate, 0.1-0.5 parts hindered amine light stabilizer TH-944 and 0.1-0.5 parts antioxidant 1010; The first diffusion layer is obtained by coating a first coating liquid comprising 100 parts epoxy acrylate resin, 5 to 15 parts first diffusion particles, 1 to 5 parts DPHA, 10 to 30 parts IBOA, and 1 to 3 parts TPO onto a PET substrate layer and curing it. The second diffusion layer is formed by coating a PET substrate layer with a second coating liquid comprising 10-20 parts NANOCRYL® C140, 30-50 parts reactive diluent, 20-40 parts acrylate oligomer, 10-25 parts second diffusion particles, 1-4 parts blue light absorber, 1-3 parts TPO, 0.1-0.5 parts leveling agent, and 0.1-0.5 parts defoamer and curing it. The preparation process of the first diffused particle is as follows: S1-1. Add 100 mL of a 1:1 mixture of ethanol and deionized water to a reaction flask, add 1.2 g of polyvinylpyrrolidone and stir until homogeneous. Heat to 70 °C, add 10-20 g of styrene monomer and 0.05-0.2 g of AIBN initiator, and polymerize under nitrogen protection for 12 h. Centrifuge the obtained product, wash with ethanol and dry to obtain seed microspheres; take 10 g and disperse in 400 mL of an aqueous solution containing 1 wt% PVA, stir until homogeneous and set aside. S1-2. Add 20-30g toluene, 40-50g styrene, 1-3g benzoyl peroxide and 2-4g divinylbenzene to a reaction flask and stir until they are evenly mixed. Then emulsify in 100mL of 0.2wt% sodium dodecyl sulfonate aqueous solution, and then dropwise add to the seed microsphere dispersion. Stir and swell at room temperature for 12-24h, raise the temperature to 70℃, and polymerize under nitrogen protection for 24h. Collect the microspheres by centrifugation and dry at low temperature. S1-3. The collected microspheres (5g) were redispersed in 100 mL of a 1:1 mixture of ethanol and deionized water, 5 mL of tetraethyl orthosilicate and 1 mL of ammonia were added, and the mixture was stirred at room temperature for 6-8 h. After centrifugation and washing with water, the microspheres were placed in a Soxhlet extractor and extracted with anhydrous ethanol. After vacuum drying at 50 °C, porous core-shell composite microspheres, i.e., the first diffusion particles, were obtained.
[0020] The preparation process of the second diffused particle is as follows: S2-1. 10 mL of KH570 was placed in a mixed solvent of 100 mL of water and ethanol for hydrolysis. 5 g of cerium oxide was dispersed in 50 mL of anhydrous ethanol and then added dropwise to the hydrolysis solution of the silane coupling agent to obtain modified cerium oxide. S2-2. Modified cerium oxide was dispersed in 100 mL of water / ethanol mixed solvent, 2 g of polyvinylpyrrolidone, 80 g of methyl methacrylate and 0.8 g of initiator AIBN were added, nitrogen gas was introduced to remove oxygen from the system, the temperature was raised to 60-70℃ and reacted for 24 h, the product was centrifuged, washed with ethanol and dried to obtain PMMA microspheres. S2-3. Disperse 10g of PMMA microspheres in 1L of 0.2wt% PDADMAC aqueous solution, stir at room temperature for 60-120min, centrifuge, wash with water and dry to obtain positively charged hybrid particles; take nano-SiO2 and ultrasonically disperse it in deionized water, adjust the pH to 7.5-8.0 with ammonia water, ultrasonically disperse for 30min to obtain a stable dispersion with a solid content of 1wt%; S2-4. The positively charged hybrid particles are redispersed in deionized water and added dropwise to the stable dispersion while stirring. The mass ratio of SiO2 to hybrid particles is 1:10~15. After the addition is complete, continue stirring at room temperature for 1 hour, centrifuge, wash with water, and then dry under low temperature vacuum.
[0021] The raw materials used in this invention, such as styrene and methyl methacrylate, are conventional reagents, and are purchased from brands such as Sinopharm Group and Aladdin, which will not be described in detail in this application. The remaining raw materials are shown in Table 1.
[0022] In addition, it should be noted that the term "parts" as used in this article refers to "parts by weight".
[0023] Table 1 Example 1: 1) The raw materials for the PET substrate layer, namely 100 parts of optical grade PET chips, 3 parts of sodium isophthalate-5-sulfonate, 0.3 parts of hindered amine light stabilizer TH-944 and 0.3 parts of antioxidant 1010, were dried, mixed, and then melt-extruded in a twin-screw extruder to form a cast sheet. 2) The cast sheet is biaxially stretched, cooled and shaped to obtain a film with a total thickness of 70 μm, and then corona treated; 3) Mix the first coating liquid according to the formula: 100 parts epoxy acrylic resin, 10 parts first diffusion particles, 5 parts DPHA, 30 parts IBOA, and 3 parts TPO evenly, and then coat it on the film surface by slit coating. After UV curing, the dry film thickness is 8μm. 4) Prepare the second coating solution. Weigh each raw material according to the formula. Premix 30 parts of acrylate oligomer, 40 parts of reactive diluent, 3 parts of photoinitiator, 0.3 parts of leveling agent, and 0.3 parts of defoamer. Add 15 parts of NANOCRYL® C140 and stir and grind thoroughly. Finally, add 18 parts of second diffusion particles and 4 parts of blue light absorber. Degas under vacuum and then coat the other side of the film by slit coating. After UV curing, the dry film thickness is 12μm.
[0024] Example 2: 1) The raw materials for the PET substrate layer, namely 100 parts of optical grade PET chips, 3 parts of sodium isophthalate-5-sulfonate, 0.3 parts of hindered amine light stabilizer TH-944 and 0.3 parts of antioxidant 1010, were dried, mixed, and then melt-extruded in a twin-screw extruder to form a cast sheet. 2) The cast sheet is biaxially stretched, cooled and shaped to obtain a film with a total thickness of 70 μm, and then corona treated; 3) Mix the first coating liquid according to the formula: 100 parts epoxy acrylic resin, 5 parts first diffusion particles, 4 parts DPHA, 20 parts IBOA, and 2 parts TPO evenly, and then coat it on the film surface by slit coating. After UV curing, the dry film thickness is 8μm. 4) Prepare the second coating solution by weighing the raw materials according to the formula. Premix 40 parts of acrylate oligomer, 30 parts of reactive diluent, 3 parts of photoinitiator, 0.3 parts of leveling agent, and 0.3 parts of defoamer. Add 10 parts of organic-inorganic hybrid UV curing resin, stir and grind thoroughly. Finally, add 12 parts of second diffusion particles and 4 parts of blue light absorber. Degas under vacuum, then coat the other side of the film by slit coating and UV curing. The dry film thickness is 12μm.
[0025] Example 3: 1) The raw materials for the PET substrate layer, namely 100 parts of optical grade PET chips, 3 parts of sodium isophthalate-5-sulfonate, 0.3 parts of hindered amine light stabilizer TH-944 and 0.3 parts of antioxidant 1010, were dried, mixed, and then melt-extruded in a twin-screw extruder to form a cast sheet. 2) The cast sheet is biaxially stretched, cooled and shaped to obtain a film with a total thickness of 70 μm, and then corona treated; 3) Mix the first coating liquid according to the formula: 100 parts epoxy acrylic resin, 15 parts first diffusion particles, 5 parts DPHA, 30 parts IBOA, and 2 parts TPO evenly, and then coat it on the film surface by slit coating. After UV curing, the dry film thickness is 8μm. 4) Prepare the second coating solution by weighing the raw materials according to the formula. Premix 20 parts of epoxy acrylate oligomer, 50 parts of reactive diluent, 3 parts of photoinitiator, 0.3 parts of leveling agent, and 0.3 parts of defoamer. Add 20 parts of organic-inorganic hybrid UV curing resin, stir and grind thoroughly. Finally, add 25 parts of second diffusion particles and 4 parts of blue light absorber. Degas under vacuum, then coat the other side of the film by slit coating and UV curing. The dry film thickness is 12 μm.
[0026] Comparative Example 1: Same as Example 1, except that the PET substrate layer is made of pure optical grade PET.
[0027] Comparative Example 2: Same as Example 1, except that the first diffusion particles of the first diffusion layer are the seed microspheres obtained in step S1-1.
[0028] Comparative Example 3: Same as Example 1, except that the first diffusion particles of the first diffusion layer are the swollen microspheres obtained in step S1-2.
[0029] Comparative Example 4: Same as Example 1, except that the second diffusion particles in the second diffusion layer did not undergo electrostatic self-assembly to adsorb SiO2.
[0030] Comparative Example 5: Same as Example 1, except that the second diffusion particles in the second diffusion layer are PMMA microspheres.
[0031] Comparative Example 6: Same as Example 1, except that the organic-inorganic hybrid UV-curable resin in the second diffusion layer is replaced by an equal amount of acrylate oligomer.
[0032] Comparative Example 7: Same as Example 1, except that the second diffusion layer does not contain a blue light absorber.
[0033] Performance testing: Haze and transmittance: The transmittance / haze was measured using a WGT-S type transmittance / haze meter (Shanghai Precision Scientific Instruments Co., Ltd.); three points were taken from the center and edge of each sample, and the average value was taken.
[0034] Weather resistance: Stability in high temperature and high humidity environments. The sample was placed in a constant temperature and humidity chamber at 85℃ / 85%RH for 1000 h. After removal, the yellowing index Δb was tested using a colorimeter.
[0035] Peel strength: The 180° peel strength was tested using a universal testing machine according to the method of GB / T 8808-2023; the sample width was 25 mm, the peel speed was 50 mm / min, and the average peak load of 5 tests was taken, with the unit being N / cm.
[0036] Pencil hardness: Refer to GB / T 6739-2006, 500g load, Mitsubishi pencil, test the surface hardness of the second diffusion layer; Blue light blocking rate: Using a Shimadzu UV-2600 spectrophotometer, the scanning range was 380-450 nm, and the blocking rate at 430 nm was calculated.
[0037] The results are recorded in Table 2.
[0038] Table 2 Referring to Table 1, it was observed that the haze of Examples 1-3 increased with the increase of the first and second diffusing particles, while the light transmittance decreased, indicating that Example 1 had relatively better overall performance. Comparing Comparative Examples 2 and 3, the haze improvement effect of the unporous PS seed microspheres was significantly worse than that of the other examples and comparative examples. Although the haze of the porous microspheres without SiO2 deposition after swelling was improved to 83.6% compared to Comparative Example 2, it still did not meet the requirements. Observing Comparative Examples 4 and 5, the role of the second diffusing particles is mainly to improve surface hardness, weather resistance, and blue light protection. The film made of diffusing particles without SiO2 coating has poor hardness and an increased yellowing index. The pure PMMA microspheres, without CeO2 coating or SiO2 coating, showed a significant decrease in both hardness and weather resistance, indicating that CeO2 encapsulation not only provides blue light absorption but also assists in anti-aging. In addition, the pure PET film layer in Comparative Example 1 had relatively weaker bonding with the diffusion layer, and the lack of additives also led to an increase in the yellowing index. Comparative Example 6 used ordinary acrylate oligomers instead of organic-inorganic hybrid photocurable resin. The pencil hardness was only B, and the yellowing index increased after aging, indicating that silica sol-modified acrylate resin significantly improved hardness and anti-yellowing ability. Comparative Example 7, without added blue light absorber, showed a significant decrease in blue light blocking rate to only 30.2%. Compared with Comparative Example 5, the blue light blocking rate of Comparative Example 5 decreased to 37.6%, attributed to the weak scattering absorption of the blue light absorber, the resin matrix, and PMMA itself. In Comparative Example 7, the blue light blocking rate was attributed to CeO2 embedded in the second diffuser particles, but its effect was less than that of the blue light absorber, confirming the synergistic effect of the blue light absorber.
[0039] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.
Claims
1. A high-durability blue light blocking optical film, characterized in that, include: The PET substrate layer is made by melt extrusion of optical-grade PET chips, sodium isophthalate-5-sulfonate, hindered amine light stabilizers and antioxidants; The first diffusion layer is obtained by coating a first coating liquid, including epoxy acrylic resin and first diffusion particles, onto a PET substrate layer and curing it. The second diffusion layer is obtained by coating a PET substrate layer with a second coating liquid comprising an organic-inorganic hybrid UV curable resin, second diffusion particles, and a blue light absorber and curing it. The preparation process of the first diffused particle is as follows: firstly, PS seed microspheres are prepared by dispersion polymerization, then porous microspheres are prepared by swelling polymerization, and finally, nano-silica particles are deposited on its surface to obtain the particle. The preparation process of the second diffused particles is as follows: Cerium oxide is treated with a double-bonded silane coupling agent and then dispersed and polymerized with methyl methacrylate to obtain microspheres. These microspheres are then placed in PDADMAC aqueous solution for adsorption to obtain hybrid particles with positively charged surfaces. Finally, they are obtained by electrostatic self-assembly adsorption with SiO2 aqueous dispersion. The organic-inorganic hybrid UV-curable resin is a silica sol-modified acrylate resin.
2. The high-durability blue light blocking optical film according to claim 1, characterized in that, The PET substrate layer, by weight, comprises 100 parts optical-grade PET chips, 2-5 parts sodium isophthalate-5-sulfonate, 0.1-0.5 parts hindered amine light stabilizer, and 0.1-0.5 parts antioxidant; the hindered amine light stabilizer is TH-944; and the antioxidant is Irganox 1010.
3. The high-durability blue light blocking optical film according to claim 1, characterized in that, The first coating liquid, by weight, comprises 100 parts epoxy acrylate resin, 5-15 parts first diffusion particles, 1-5 parts DPHA, 10-30 parts IBOA, and 1-3 parts TPO; the dry film thickness is 5-12 μm.
4. The high-durability blue light blocking optical film according to claim 1, characterized in that, The preparation process of the first diffusing particle is as follows: S1-1. Add ethanol / deionized water mixed solvent to the reaction flask, add polyvinylpyrrolidone and stir evenly, heat to 70℃, add styrene monomer and AIBN initiator, and polymerize under nitrogen protection for 12h. Centrifuge the obtained product, wash with ethanol and dry to obtain seed microspheres, disperse them in polyvinylpyrrolidone aqueous solution and stir evenly for later use. S1-2. Add toluene, styrene, benzoyl peroxide and divinylbenzene to the reaction flask and stir until they are evenly mixed. Emulsify evenly in an aqueous solution containing sodium dodecyl sulfate. Slowly add to the seed microsphere dispersion and stir at room temperature to swell for 12-24 h. Heat to 70℃ and polymerize for 24 h. Centrifuge to collect the microspheres. S1-3. The collected microspheres are redispersed in a mixed solvent of ethanol / deionized water. Tetraethyl orthosilicate and ammonia are added. The mixture is stirred at room temperature to allow the SiO2 generated by the hydrolysis of tetraethyl orthosilicate to be deposited on the surface of the microspheres and the inner wall of the pores. The microspheres are then separated by centrifugation and extracted to obtain the final product.
5. The high-durability blue light blocking optical film according to claim 4, characterized in that, The preparation process of the first diffusing particle is as follows: S1-1. Add 100 mL of a 1:1 mixture of ethanol and deionized water to a reaction flask, add 1.2 g of polyvinylpyrrolidone and stir until homogeneous. Heat to 70 °C, add 10-20 g of styrene monomer and 0.05-0.2 g of AIBN initiator, and polymerize under nitrogen protection for 12 h. Centrifuge the obtained product, wash with ethanol and dry to obtain seed microspheres; take 10 g and disperse in 400 mL of an aqueous solution containing 1 wt% PVA, stir until homogeneous and set aside. S1-2. Add 20-30g toluene, 40-50g styrene, 1-3g benzoyl peroxide and 2-4g divinylbenzene to a reaction flask and stir until they are evenly mixed. Then emulsify in 100mL of 0.2wt% sodium dodecyl sulfonate aqueous solution, and then dropwise add to the seed microsphere dispersion. Stir and swell at room temperature for 12-24h, raise the temperature to 70℃, and polymerize under nitrogen protection for 24h. Collect the microspheres by centrifugation and dry at low temperature. S1-3. The collected microspheres (5g) were redispersed in 100 mL of a 1:1 mixture of ethanol and deionized water, 5 mL of tetraethyl orthosilicate and 1 mL of ammonia were added, and the mixture was stirred at room temperature for 6-8 h. After centrifugation and washing with water, the microspheres were placed in a Soxhlet extractor and extracted with anhydrous ethanol. After vacuum drying at 50 °C, porous core-shell composite microspheres, i.e., the first diffusion particles, were obtained.
6. The high-durability blue light blocking optical film according to claim 1, characterized in that, The second coating liquid, by weight fraction, comprises 10-20 parts of organic-inorganic hybrid UV curing resin, 30-50 parts of reactive diluent, 20-40 parts of acrylate oligomer, 10-25 parts of second diffusion particles, 1-4 parts of blue light absorber, 1-3 parts of TPO, 0.1-0.5 parts of leveling agent, and 0.1-0.5 parts of defoamer; the dry film thickness is 8-12 μm.
7. The high-durability blue light blocking optical film according to claim 1, characterized in that, The preparation process of the second diffused particle is as follows: S2-1. The silane coupling agent containing double bonds is placed in a mixed solvent of water and ethanol for hydrolysis. Cerium oxide is dispersed in anhydrous ethanol and then added dropwise to the hydrolysis solution of the silane coupling agent to obtain modified cerium oxide. S2-2. Modified cerium oxide was dispersed in a water / ethanol mixed solvent, polyvinylpyrrolidone, methyl methacrylate and initiator AIBN were added, nitrogen gas was introduced to remove oxygen from the system, the temperature was raised to 60-70℃ and the reaction was carried out for 24 hours. The product was centrifuged, washed with ethanol and dried to obtain PMMA microspheres. S2-3. Disperse PMMA microspheres in 0.2wt% PDADMAC aqueous solution, stir at room temperature for 60-120 min, centrifuge, wash with water and dry to obtain positively charged hybrid particles; take nano-SiO2 and ultrasonically disperse in deionized water, adjust the pH to 7.5-8.0 with ammonia water, ultrasonically disperse for 30 min to obtain a stable dispersion with a solid content of 1wt%. S2-4. The positively charged hybrid particles are redispersed in deionized water and added dropwise to the stable dispersion while stirring. The mass ratio of SiO2 to hybrid particles is 1:10~15. After the addition is complete, continue stirring at room temperature for 1 hour, centrifuge, wash with water, and then dry under low temperature vacuum.
8. The high-durability blue light blocking optical film according to claim 1, characterized in that, The organic-inorganic hybrid UV-curable resin is a NANOCRYL® series nano silica acrylate dispersion.
9. The high-durability blue light blocking optical film according to claim 1, characterized in that, The blue light absorber is one or more of blue light absorber 46, blue light absorber 47, blue light absorber 93 or blue light absorber 605.
10. A method for preparing a high-durability blue light blocking optical film according to any one of claims 1-9, characterized in that, Includes the following steps: 1) The PET substrate layer raw material is dried, blended, and then fed into a twin-screw extruder for melt extrusion to form a cast sheet; 2) The cast sheet is biaxially stretched, cooled and shaped to obtain a film with a total thickness of 50~70 μm, and then corona treated; 3) Mix the first coating liquid evenly according to the formula, and then coat it onto the film surface by slit coating, followed by UV curing; 4) Prepare the second coating liquid. Weigh each raw material according to the formula, premix the oligomer, reactive diluent, photoinitiator, leveling agent and defoamer, add organic-inorganic hybrid UV curing resin, stir and grind thoroughly, finally add the second diffusion particles and blue light absorber, degas under vacuum, and then coat the other side of the film by slit coating and UV curing to obtain the coating liquid.