Self-repairing anti-scraping optical thin film, preparation method thereof and application of self-repairing anti-scraping optical thin film in display device

Abstract

The invention belongs to the technical field of self-repairing materials, and particularly relates to a self-repairing anti-scraping optical thin film, a preparation method thereof and application of the self-repairing anti-scraping optical thin film in a display device. By reasonably setting the thickness and material composition of the base material layer, the self-repairing functional layer and the anti-scraping layer, all the layers have a synergistic effect, and the self-repairing performance, the anti-scraping performance and the optical performance can be achieved at the same time. The self-repairing functional layer is compounded by polyurethane elastomer and polycaprolactone glycol, and nano silicon dioxide is added, so that not only are the self-repairing performance and the mechanical performance improved, but also the self-repairing efficiency is enhanced; and the anti-scraping layer is formed by combining organic silicon resin and nano silicon nitride, so that the anti-scraping performance is ensured, and meanwhile, the influence on the optical performance is avoided.

Description

Technical Field

[0001] This invention belongs to the field of self-healing materials technology, specifically relating to a self-healing scratch-resistant optical thin film, its preparation method, and its application in display devices. Background Technology

[0002] In the field of display devices, optical thin films are an important component, and their performance directly affects the display effect and lifespan of the display device. With the continuous development of display technology, the performance requirements for optical thin films are also becoming increasingly stringent. They not only need to possess good optical properties, such as high light transmittance and low haze, but also excellent mechanical properties, such as scratch resistance and self-healing properties.

[0003] Currently, existing optical thin films have many shortcomings in terms of scratch resistance and self-healing properties. Some optical thin films, in order to improve scratch resistance, often use materials with high hardness, resulting in poor self-healing performance. Once scratched, they are difficult to repair themselves, affecting the aesthetics and lifespan of display devices. Other optical thin films, while possessing some self-healing properties, have weak scratch resistance and are easily scratched. Furthermore, most existing self-healing optical thin films have low self-healing efficiency, requiring specific conditions (such as high temperature and high humidity) to achieve good self-healing effects, limiting their widespread adoption in practical applications. Simultaneously, some optical thin films, while possessing self-healing and scratch resistance, suffer from compromised optical performance, such as decreased light transmittance and increased haze, failing to meet the high-quality optical performance requirements of display devices.

[0004] Therefore, developing an optical thin film that can simultaneously achieve self-healing properties, scratch resistance, and good optical performance is of great practical significance. Summary of the Invention

[0005] The purpose of this invention is to provide a self-healing and scratch-resistant optical film, its preparation method, and its application in display devices. By reasonably setting the thickness and material composition of the substrate layer, the self-healing functional layer, and the scratch-resistant layer, the layers work together to achieve self-healing performance, scratch resistance, and optical performance simultaneously.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A self-healing and scratch-resistant optical film has a structure consisting of a substrate layer, a self-healing functional layer, and a scratch-resistant layer from bottom to top. Preferably, the substrate layer includes any one of PET film, CPI film, COP film, and ultrathin flexible glass.

[0007] Preferably, the thickness of the substrate layer is 25-100 µm.

[0008] The self-healing functional layer is made of a self-healing material; the self-healing material, by weight, includes 50-70 parts of polyurethane elastomer, 10-20 parts of polycaprolactone diol, 5-10 parts of modified nano-silica, 1-3 parts of photoinitiator, and 2-5 parts of crosslinking agent.

[0009] Preferably, the method for preparing the polyurethane elastomer includes the following steps: mixing 4,4'-diphenylmethane diisocyanate with poly(tetrahydrofuran) and reacting at 80°C for 2 hours to obtain a prepolymer; adding a chain extender and reacting at 60°C for 1 hour to obtain the final product.

[0010] Preferably, the poly(tetrahydrofuran) has a relative molecular mass of 1900-2100 and a hydroxyl value of 53-59 mgKOH / g.

[0011] In some preferred embodiments, the poly(tetrahydrofuran) is sourced from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0012] Preferably, the molar ratio of 4,4'-diphenylmethane diisocyanate to polytetrahydrofuran diol is (1.8-2.2):1; more preferably, it is 2:1.

[0013] Preferably, the chain extender comprises ethylenediamine.

[0014] Preferably, the molar ratio of the prepolymer to the chain extender is 1:1.

[0015] By manufacturing a self-made polyurethane elastomer and controlling the molar ratio of raw materials and reaction conditions during the preparation process, the self-healing properties of the film can be improved. This is likely because the use of 4,4'-diphenylmethane diisocyanate, polytetrahydrofuran, and ethylenediamine chain extenders introduces a large number of urea and urethane groups into the elastomer molecular chain, forming a dense dynamic hydrogen bond network. When scratches occur on the film, the hydrogen bonds break and recombine at room temperature, achieving self-repair. At the same time, the polytetrahydrofuran segments provide suitable flexibility, promote molecular chain migration, and accelerate the repair process.

[0016] Preferably, the polycaprolactone diol has a molecular weight of 1200-2800 and a hydroxyl value of 61-53 mgKOH / g.

[0017] In some preferred embodiments, the polycaprolactone diol is sourced from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0018] Preferably, the method for preparing the modified nano-silica includes the following steps: adding nano-silica to silane hydrolysate 1, refluxing at 70-80℃ for 3-5 hours, centrifuging, collecting the precipitate, washing with anhydrous ethanol 2-3 times, and vacuum drying to obtain the product.

[0019] Preferably, the average particle size of the nano-silica is 10-14 nm, and the specific surface area is 200±25 m². 2 / g.

[0020] In some preferred embodiments, the nano-silica is sourced from Evonik Industries, AEROSIL 200.

[0021] Preferably, the preparation method of the silane hydrolysate 1 includes the following steps: adding silane coupling agent 1 to an ethanol aqueous solution, adjusting the pH to 3-4, stirring at 200-400 r / min and 28-32℃ for 25-35 min, and then obtaining the solution.

[0022] Preferably, the ethanol aqueous solution contains 70%-80% ethanol by mass.

[0023] Preferably, the silane coupling agent 1 includes KH570.

[0024] Preferably, the mass ratio of the silane coupling agent 1 to the aqueous ethanol solution is 1:(40-60).

[0025] Preferably, the mass of silane coupling agent 1 in the silane hydrolysate 1 is 5%-8% of the mass of nano-silica.

[0026] Preferably, the specific conditions for vacuum drying are: vacuum degree of 0.008-0.009 MPa, temperature of 55-65℃, and time of 10-15 h.

[0027] Preferably, the mass ratio of the polyurethane elastomer to the modified nano-silica is (5-10):1.

[0028] Preferably, the photoinitiator includes, but is not limited to, 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0029] Preferably, the crosslinking agent comprises isophorone diisocyanate.

[0030] Preferably, the mass ratio of the polyurethane elastomer, polycaprolactone diol, and crosslinking agent is (15-25):(3-5):1.

[0031] Preferably, the thickness of the self-healing functional layer is 5-15 μm.

[0032] By using a blend of polyurethane elastomer and polycaprolactone diol (PCL) as the substrate for the self-healing functional layer, and employing IPDI as the crosslinking agent, not only is the self-healing performance improved, but also its flexibility and structural stability are enhanced. This is likely due to the synergistic effect of the three components. The urea-based hydrogen bond network of the polyurethane elastomer provides reversible repair dynamics, while the low glass transition temperature of PCL endows the chain segments with room-temperature mobility. The two form a dynamic interpenetrating network, which accelerates molecular chain migration and recombination at the scratch site while ensuring structural stability after repair. The aliphatic six-membered ring structure of IPDI imparts moderate flexibility to the crosslinking network, and the urea bonds formed by the reaction of its isocyanate groups and hydroxyl groups possess reversible breakage-recombination capabilities, enabling rapid repair of deep scratches while maintaining the film's hardness under normal conditions. Furthermore, the selection of nano-silica with a specific particle size enhances the mechanical strength of the self-healing layer, preventing deformation due to excessive softness, without hindering molecular chain movement or affecting the repair capability. Simultaneously, the 10-14 nm particle size is below the visible light wavelength, avoiding light scattering, maintaining film transmittance while improving film toughness. However, inorganic materials have poor compatibility with organic systems and may aggregate, affecting the performance improvement effect.

[0033] Modifying nano-silica with a specific KH570 silane coupling agent can improve the compatibility between nano-silica and polyurethane elastomers, thereby enhancing the film's performance. This may be because KH570 contains double bonds, which can chemically react with the active groups of the polyurethane elastomer in the self-healing layer, enhancing interfacial bonding; and the polarity of the ethanol aqueous solution matches the hydroxyl groups on the silica surface, promoting the adsorption of the coupling agent.

[0034] The anti-scratch layer is made of an anti-scratch material; the anti-scratch material, by weight, comprises 40-60 parts of organosilicon resin, 8-15 parts of modified nano-silicon nitride, 3-6 parts of coupling agent, and 20-30 parts of solvent.

[0035] Preferably, the organosilicon resin has a dynamic viscosity of ≤120 mPa·s at 25°C and a solid content of ≤89%.

[0036] In some preferred embodiments, the silicone resin is from Wacker Chemie, Germany, SILRES® SY 231.

[0037] Preferably, the method for preparing the modified nano-silicon nitride includes the following steps: adding nano-silicon nitride to silane hydrolysate 2, refluxing at 80-90°C for 3-4 hours, filtering, washing with isopropanol 2-3 times, and drying at 100-110°C for 8-10 hours to obtain the product.

[0038] Preferably, the average particle size of the nano-silicon nitride is ≤50nm and the purity is ≥98.5%.

[0039] In some preferred embodiments, the nano-silicon nitride is sourced from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0040] Preferably, the preparation method of the silane hydrolysate 2 includes the following steps: adding silane coupling agent 2 to an isopropanol aqueous solution, adjusting the pH to 4-5, and stirring at 200-400 r / min and 38-42℃ for 35-45 min to obtain the solution.

[0041] Preferably, the isopropanol in the aqueous isopropanol solution has a mass fraction of 90%-95%.

[0042] Preferably, the silane coupling agent 2 comprises γ-glycidoxypropyltrimethoxysilane.

[0043] Preferably, the mass ratio of the silane coupling agent 2 to the isopropanol aqueous solution is 1:(30-40).

[0044] Preferably, the mass of silane coupling agent 2 in the silane hydrolysate 2 is 6%-10% of the mass of nano-silicon nitride.

[0045] Preferably, the mass ratio of the organosilicon resin to the modified nano-silicon nitride is (4-6):1.

[0046] Preferably, the coupling agent comprises γ-aminopropyltriethoxysilane.

[0047] Preferably, the solvent includes one or more of ethyl acetate, propylene glycol methyl ether acetate, isopropanol, and ethylene glycol monobutyl ether.

[0048] Preferably, the thickness of the scratch-resistant layer is 3-8 μm.

[0049] By using a composite system of silicone resin and nano-silicon nitride in the scratch-resistant layer, the hardness and weather resistance of the film can be synergistically improved. This is likely due to the synergistic effect of the silicone resin and nano-silicon nitride. The Si-O bond energy of the silicone resin is higher than that of the C-C bond, giving the coating excellent aging resistance, while the high hardness of the nano-silicon nitride can significantly improve the surface hardness of the scratch-resistant layer and resist external friction. However, nano-silicon nitride is an inorganic material, and it also suffers from compatibility and agglomeration problems. Even with the addition of coupling agents in the raw materials, their main function is to maintain processing stability and cannot fundamentally solve the intrinsic agglomeration problem of nano-silicon nitride.

[0050] By selecting a specific γ-glycidoxypropyltrimethoxysilane to modify nano-silicon nitride, the epoxy groups of γ-glycidoxypropyltrimethoxysilane can react with the hydroxyl groups of the organosilicon resin in the anti-scratch layer, thereby improving compatibility; the polarity of the isopropanol aqueous solution matches the surface characteristics of silicon nitride and is consistent with the solubility of organosilicon resin, thus avoiding agglomeration.

[0051] In the system of this invention, different silane coupling agents are selected to modify the two inorganic materials, nano-silica and nano-silicon nitride. The two modification processes are adapted to the chemical properties of the nanoparticles and the matrix respectively, to ensure uniform dispersion and avoid problems such as decreased optical performance caused by particle agglomeration.

[0052] A second aspect of the present invention provides a method for preparing the self-healing, scratch-resistant optical thin film, comprising the following steps: S1. Preparation of self-healing material: Mix the raw materials of the self-healing material and stir for 20-30 minutes at a speed of 300-500 r / min to obtain the self-healing material; S2. Preparation of anti-scratch material: Mix the raw materials of the anti-scratch material, grind for 1-2 hours, and then pass through a 200-mesh sieve to obtain the anti-scratch material; S3. Coat one side of the substrate layer with a self-healing material, cure with UV light, coat with an anti-scratch material, and heat-cur to obtain the final product. Preferably, in step S3, the specific conditions for UV curing are: light intensity of 80-100 mW / cm². 2 The irradiation time is 30-60 seconds.

[0053] Preferably, in step S3, the specific conditions for thermosetting are: temperature of 80-100℃ and time of 30-60min.

[0054] The third aspect of the present invention provides the application of the self-healing and scratch-resistant optical film in a display device, wherein the optical film is adhered to the display surface of the display device to improve the scratch resistance and self-healing performance of the display device, while ensuring the display effect of the display device.

[0055] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. This invention provides a self-healing and scratch-resistant optical film. By reasonably setting the thickness and material composition of the substrate layer, the self-healing functional layer and the scratch-resistant layer, the layers work together to achieve self-healing performance, scratch resistance and optical performance at the same time. The prepared optical film can be applied in the field of display devices.

[0056] 2. This invention improves the self-healing properties of the film by using a self-made polyurethane elastomer and controlling the molar ratio of each raw material and reaction conditions during the preparation process.

[0057] 3. This invention uses a blend of polyurethane elastomer and polycaprolactone diol as the substrate for the self-healing functional layer, and employs IPDI as the crosslinking agent for the self-healing functional layer. This not only improves the self-healing performance, but also enhances the flexibility and structural stability.

[0058] 4. This invention improves the compatibility between nano-silica and polyurethane elastomer by modifying nano-silica with a specific KH570 silane coupling agent, thereby improving the performance of the film.

[0059] 5. The present invention uses a composite system of organosilicon resin and nano-silicon nitride in the scratch-resistant layer, which can synergistically improve the hardness and weather resistance of the film. Detailed Implementation

[0060] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0061] All raw materials used in this invention are commercially available, specifically: The relative molecular mass of poly(tetrahydrofuran) is 1900-2100, the hydroxyl value is 53-59 mgKOH / g, the CAS number is 25190-06-1, and it comes from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0062] Polycaprolactone diol has a molecular weight of 1200-2800, a hydroxyl value of 61-53 mgKOH / g, and CAS number 36890-68-3. It is from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0063] The average particle size of nano-silica is 10-14 nm, and the specific surface area is 200±25 m². 2 / g, from Evonik Industries, AEROSIL 200.

[0064] The silicone resin has a dynamic viscosity of ≤120 mPa·s at 25°C and a solid content of ≤89%, and is from Wacker Chemie, Germany, SILRES® SY 231.

[0065] The nano-silicon nitride has an average particle size of ≤50nm and a purity of ≥98.5%, and comes from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0066] PET film, 50-55μm thick, with a transmittance of ≥99% and a haze of ≤0.84%, is from Shanghai Jiri Electronics Co., Ltd.

[0067] Example 1 This embodiment provides a self-healing and scratch-resistant optical film, the structure of which, from bottom to top, consists of a substrate layer, a self-healing functional layer, and a scratch-resistant layer.

[0068] The substrate layer is a PET film.

[0069] The self-healing functional layer is made of a self-healing material; the self-healing material, by weight, comprises 60 parts of polyurethane elastomer, 12 parts of polycaprolactone diol, 8 parts of modified nano-silica, 2 parts of photoinitiator, and 3 parts of crosslinking agent.

[0070] The preparation method of the polyurethane elastomer includes the following steps: mixing 4,4'-diphenylmethane diisocyanate with poly(tetrahydrofuran) and reacting at 80°C for 2 hours to obtain a prepolymer; adding a chain extender and reacting at 60°C for 1 hour to obtain the final product.

[0071] The molar ratio of 4,4'-diphenylmethane diisocyanate to polytetrahydrofuran diol is 2:1.

[0072] The chain extender is ethylenediamine.

[0073] The molar ratio of the prepolymer to the chain extender is 1:1.

[0074] The method for preparing the modified nano-silica includes the following steps: adding nano-silica to silane hydrolysate 1, refluxing at 75°C for 4 hours, centrifuging, collecting the precipitate, washing it three times with anhydrous ethanol, and drying it under vacuum to obtain the final product.

[0075] The preparation method of the silane hydrolysate 1 is as follows: add silane coupling agent 1 to an ethanol aqueous solution, adjust the pH to 3.5, stir at 300 r / min and 30℃ for 30 min, and the solution is obtained.

[0076] The ethanol aqueous solution has an ethanol mass fraction of 75%.

[0077] The silane coupling agent 1 is KH570.

[0078] The mass ratio of the silane coupling agent 1 to the aqueous ethanol solution is 1:50.

[0079] The mass of silane coupling agent 1 in the silane hydrolysate 1 is 6% of the mass of nano-silica.

[0080] The specific conditions for vacuum drying are: vacuum degree of 0.0085 MPa, temperature of 60℃, and time of 12 hours.

[0081] The photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0082] The crosslinking agent is isophorone diisocyanate.

[0083] The thickness of the self-healing functional layer is 10 μm.

[0084] The anti-scratch layer is made of an anti-scratch material; the anti-scratch material, by weight, is prepared from raw materials including 50 parts of organosilicon resin, 10 parts of modified nano-silicon nitride, 4 parts of coupling agent, and 25 parts of solvent.

[0085] The method for preparing the modified nano-silicon nitride is as follows: add nano-silicon nitride to silane hydrolysate 2, reflux at 85°C for 3.5 h, filter, wash 3 times with isopropanol, and dry at 105°C for 9 h to obtain the product.

[0086] The preparation method of the silane hydrolysate 2 is as follows: add silane coupling agent 2 to an isopropanol aqueous solution, adjust the pH to 4.5, stir at 300 r / min and 40℃ for 40 min, and the solution is obtained.

[0087] The isopropanol aqueous solution contains 92% isopropanol by mass.

[0088] The silane coupling agent 2 is γ-glycidoxypropyltrimethoxysilane.

[0089] The mass ratio of the silane coupling agent 2 to the isopropanol aqueous solution is 1:35.

[0090] The mass of silane coupling agent 2 in the silane hydrolysate 2 is 8% of the mass of nano-silicon nitride.

[0091] The coupling agent is γ-aminopropyltriethoxysilane.

[0092] The solvent is ethyl acetate.

[0093] The thickness of the scratch-resistant layer is 5 μm.

[0094] The preparation method of the self-healing scratch-resistant optical film includes the following steps: S1. Preparation of self-healing material: Mix the raw materials of the self-healing material and stir for 25 minutes at a speed of 400 r / min to obtain the self-healing material; S2. Preparation of anti-scratch material: Mix the raw materials of the anti-scratch material, grind for 2 hours, and then pass through a 200-mesh sieve to obtain the anti-scratch material; S3. Coat one side of the substrate layer with a self-healing material, cure with UV light, coat with an anti-scratch material, and heat-cur to obtain the final product. In step S3, the specific conditions for UV curing are: light intensity of 90 mW / cm². 2 The irradiation time is 45 seconds.

[0095] In step S3, the specific conditions for heat curing are: temperature 90℃ and time 45min.

[0096] Example 2 The difference between this embodiment and Embodiment 1 is that the self-healing material, by weight, consists of 55 parts polyurethane elastomer, 15 parts polycaprolactone diol, 8 parts modified nano silica, 2 parts photoinitiator, and 3 parts crosslinking agent.

[0097] Comparative Example 1 The difference between this comparative example and Example 1 is that the molar ratio of 4,4'-diphenylmethane diisocyanate and polytetrahydrofuran diol is 1:1.

[0098] Comparative Example 2 The difference between this comparative example and Example 1 is that the chain extender is butanediol.

[0099] Comparative Example 3 The difference between this comparative example and Example 1 is that the molecular weight of polycaprolactone diol is 3000, the CAS number is 36890-68-3, and it comes from Shandong Huian Chemical Co., Ltd.

[0100] Comparative Example 4 The difference between this comparative example and Example 1 is that the self-healing material, by weight, consists of 60 parts of polyurethane elastomer, 12 parts of polycaprolactone diol, 8 parts of nano-silica, 2 parts of photoinitiator, and 3 parts of crosslinking agent.

[0101] Comparative Example 5 The difference between this comparative example and Example 1 is that the silane hydrolysate 1 is γ-glycidoxypropyltrimethoxysilane.

[0102] Comparative Example 6 The difference between this comparative example and Example 1 is that the crosslinking agent is trimethylolpropane triacrylate.

[0103] Comparative Example 7 The difference between this comparative example and Example 1 is that the anti-scratch material, by weight, is prepared from raw materials including 50 parts of organosilicon resin, 10 parts of nano-silicon nitride, 4 parts of coupling agent, and 25 parts of solvent.

[0104] Comparative Example 8 The difference between this comparative example and Example 1 is that the silane coupling agent 2 is KH570.

[0105] Performance testing Referencing GB / T 2410-2008, the transmittance and haze of the film were tested using visible light (380-780nm) as the light source. The highest transmittance value was recorded, and the average value was taken from three tests. Referring to GB / T 6739-2006, the pencil hardness of the scratch-resistant side of the film was tested with a 750g load, a triangular pencil, and a 45° angle scratch. Referring to GB / T 23989-2009, the transmittance retention rate of the scratch-resistant side of the film was tested using steel wool friction. The initial transmittance was recorded as T0. Using #0000 steel wool, a 1kg load was applied, and the sample surface was rubbed 10,000 times at a rate of 30 times / min and a stroke of 50mm. The transmittance after friction was recorded as T1. The transmittance retention rate was calculated as (T1 / T0) × 100%, and the average value was taken from three tests. Room temperature self-healing rate test: A 1H pencil (500g load) was used to scratch the surface of the scratch-resistant layer, forming a scratch approximately 20mm long and 50μm wide. The initial width W0 was measured under a microscope. After being placed at 25℃ for 24 hours, the width W1 of the scratch after repair was measured under a microscope. The self-healing rate = (W0-W1) / W0 × 100%. The average value of three scratches was taken. Repair rate after 200,000 bends: Referring to the bending device in GB / T 15256-1994, the sample was fixed on the bending test machine. The bending angle was set to 180°, the bending radius to 1mm, and the speed to 30 times / min. After 100,000 consecutive bends, the repair rate was measured according to the room temperature self-healing rate test procedure and recorded as the repair rate after bending. The average value of three tests was taken. The results are shown in Table 1.

[0106] Table 1 Measurement Results

[0107] According to statistics, the self-healing and scratch-resistant optical films prepared in Examples 1-2 of this invention have high light transmittance and low haze, indicating that they have excellent optical performance and can be applied to display devices. At the same time, they have high light transmittance retention under pencil hardness and steel wool friction, indicating that they have good scratch resistance, high self-healing rate at room temperature, and still have a high self-healing rate after 100,000 bends. In Comparative Example 1, the molar ratio was reduced to 1:1, resulting in insufficient urea group density in the polyurethane elastomer and a decrease in self-healing ability. In Comparative Example 2, the chain extender was butanediol, and the prepared polyurethane elastomer did not contain urea groups, leading to the breakage of the dynamic hydrogen bond network, a significant decrease in self-healing rate, and deterioration in performance after bending. In Comparative Example 3, the molecular weight of polycaprolactone diol exceeded the limit, hindering chain segment movement and reducing the self-healing rate. In Comparative Example 4, the unmodified nano-silica had poor dispersibility, resulting in decreased light transmittance, increased haze, and poor optical performance. Simultaneously, the self-healing rate was also affected by particle agglomeration. In Comparative Example 5, silane coupling agent 1 was replaced with γ-glycidyl etheroxypropyltrimethoxysilane, which, along with the polyurethane... The compatibility decreased, and the self-healing rate decreased. In Comparative Example 6, the crosslinking agent was replaced with trimethylolpropane triacrylate, resulting in excessively high crosslinking density and a decrease in all properties. In Comparative Example 7, the unmodified nano-silicon nitride resulted in poor dispersion of the scratch-resistant layer, reduced pencil hardness, and a significant decrease in light transmittance retention due to steel wool friction. Furthermore, the reduced scratch-resistant layer performance led to puncture phenomena during self-healing performance measurements, further affecting the self-healing performance. In Comparative Example 8, the silane coupling agent 2 was replaced with KH570, resulting in insufficient compatibility with the silicone resin, poor silicon nitride dispersion, and decreased scratch resistance. Again, the reduced scratch-resistant layer performance led to puncture phenomena during self-healing performance measurements, further affecting the self-healing performance. Therefore, the self-healing scratch-resistant optical film prepared using the raw materials and methods described in this application can simultaneously achieve self-healing performance, scratch resistance, and optical performance, and can be applied in the field of optical display devices.

[0108] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A self-healing, scratch-resistant optical film, characterized in that, Its structure, from bottom to top, consists of a substrate layer, a self-healing functional layer, and a scratch-resistant layer; The self-healing functional layer is made of a self-healing material; the self-healing material, by weight, includes 50-70 parts of polyurethane elastomer, 10-20 parts of polycaprolactone diol, 5-10 parts of modified nano-silica, 1-3 parts of photoinitiator, and 2-5 parts of crosslinking agent. The method for preparing the polyurethane elastomer includes the following steps: mixing 4,4'-diphenylmethane diisocyanate with poly(tetrahydrofuran) and reacting at 80°C for 2 hours to obtain a prepolymer; adding a chain extender and reacting at 60°C for 1 hour to obtain the final product.

2. The self-healing, scratch-resistant optical film according to claim 1, characterized in that, The relative molecular mass of the poly(tetrahydrofuran) is 1900-2100, and the hydroxyl value is 53-59 mgKOH / g.

3. The self-healing, scratch-resistant optical film according to claim 2, characterized in that, The chain extender includes ethylenediamine.

4. The self-healing, scratch-resistant optical film according to claim 1, characterized in that, The method for preparing the modified nano-silica includes the following steps: adding nano-silica to silane hydrolysate 1, refluxing at 70-80℃ for 3-5 hours, centrifuging, collecting the precipitate, washing with anhydrous ethanol 2-3 times, and vacuum drying to obtain the product.

5. The self-healing, scratch-resistant optical film according to claim 4, characterized in that, The preparation method of the silane hydrolysate 1 is as follows: add silane coupling agent 1 to an ethanol aqueous solution, adjust the pH to 3-4, stir at 200-400 r / min and 28-32℃ for 25-35 min, and the solution is obtained.

6. The self-healing, scratch-resistant optical film according to claim 5, characterized in that, The silane coupling agent 1 includes KH570.

7. The self-healing, scratch-resistant optical film according to claim 1, characterized in that, The crosslinking agent includes isophorone diisocyanate.

8. The self-healing, scratch-resistant optical film according to claim 1, characterized in that, The anti-scratch layer is made of an anti-scratch material; the anti-scratch material, by weight, comprises 40-60 parts of organosilicon resin, 8-15 parts of modified nano-silicon nitride, 3-6 parts of coupling agent, and 20-30 parts of solvent.

9. A method for preparing a self-healing, scratch-resistant optical thin film according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Preparation of self-healing material: Mix the raw materials of the self-healing material and stir for 20-30 minutes at a speed of 300-500 r / min to obtain the self-healing material; S2. Preparation of anti-scratch material: Mix the raw materials of the anti-scratch material, grind for 1-2 hours, and then pass through a 200-mesh sieve to obtain the anti-scratch material; S3. Coat one side of the substrate layer with a self-healing material, cure with UV light, coat with an anti-scratch material, and heat-cur to obtain the final product.

10. The application of a self-healing, scratch-resistant optical film according to any one of claims 1 to 8 in a display device.

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