Highway LED transparent lens face shield and preparation method thereof

Abstract

The present application relates to the technical field of lens mask, especially to a highway LED transparent lens mask and a preparation method thereof, which comprises the following components by weight: 80-90 parts of poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA); 0.5-2.0 parts of nano-scale cerium-doped zinc oxide (Ce-ZnO) quantum dots; 5-10 parts of random ethylene-methyl acrylate-glycidyl methacrylate terpolymer; 1-3 parts of photochromic spiropyran derivative modified silica nanoparticles; and 1-3 parts of hyperbranched fluorinated polyether. The high light transmittance is ensured, and the active sites are provided through the PGMA block, which is conducive to the uniform dispersion and chemical bonding of other functional components. The nano-scale cerium-doped zinc oxide (Ce-ZnO) quantum dots are introduced to realize efficient ultraviolet blocking and light stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lens cover, in particular to a highway LED transparent lens cover and a preparation method thereof. BACKGROUND

[0002] With the rapid development of intelligent transportation systems, highway LED display screens have become an important device for providing real-time traffic information and safety warnings. However, these display screens are exposed to complex outdoor environments for a long time, facing many challenges. First, strong sunlight and ultraviolet radiation can cause the display screen cover material to age and yellow, affecting the clarity and readability of the information. Second, frequent temperature changes and humidity fluctuations can easily cause micro-cracks in the cover material, reducing its service life. Third, the accumulation of pollutants such as rain, snow and dust can seriously affect the display effect and increase maintenance costs. In addition, the problem of glare under strong light at night has always plagued the visual comfort and driving safety of drivers.

[0003] In the prior art, commonly used transparent cover materials such as polymethyl methacrylate (PMMA) or polycarbonate (PC) have good light transmission, but perform poorly in terms of ultraviolet resistance, self-cleaning and anti-glare. Some improvement schemes, such as adding ultraviolet absorbers or coating anti-reflection coatings, have improved in some aspects, but often at the expense of other properties of the material. For example, adding ultraviolet absorbers can reduce the light transmission of the material, and coating anti-reflection coatings can affect the weather resistance of the material. In addition, these methods can usually only solve a single problem and cannot comprehensively improve the overall performance of the material.

[0004] Therefore, it is urgent to develop a new type of highway LED transparent lens cover material that can simultaneously have excellent light transmission, ultraviolet resistance, self-repairing ability, intelligent anti-glare function and self-cleaning effect to meet the long-term use requirements in complex outdoor environments. SUMMARY

[0005] The present application is directed to the above problems, and proposes an innovative highway LED transparent lens cover and a preparation method thereof.

[0006] The purpose of the present application is to provide a highway LED transparent lens cover, which comprises the following components by weight:

[0007] 80-90 parts of poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA);

[0008] 0.5-2.0 parts of nano-sized cerium-doped zinc oxide Ce-ZnO quantum dots;

[0009] 5-10 parts of random ethylene-methyl acrylate-glycidyl methacrylate terpolymer;

[0010] 1-3 parts of photochromic spiropyran derivative modified silica nanoparticles;

[0011] 1-3 parts of hyperbranched fluorinated polyether.

[0012] Specifically, the molecular weight of the poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA) is 70,000-80,000 g / mol, and the block ratio PMMA:PGMA is 7.5:2.5 to 8.5:1.5.

[0013] Specifically, the particle size of the nanoscale cerium-doped zinc oxide Ce-ZnO quantum dots is 5-10 nm, and the cerium doping amount is 1-5 mol%.

[0014] Specifically, the content of glycidyl methacrylate in the random ethylene-methyl acrylate-glycidyl methacrylate terpolymer is 7.5-8.5 wt%, and the melt index (190°C / 2.16 kg) is 6-8 g / 10 min.

[0015] Specifically, the particle size of the photochromic spiropyran derivative modified silica nanoparticles is 20-50 nm, and the spiropyran modification density is 0.5-1.0 μmol / m 2 .

[0016] Specifically, the molecular weight of the hyperbranched fluorinated polyether is 2000-3000 g / mol, and the hydroxyl value is 155-175 mgKOH / g.

[0017] The preparation method of the formula high-speed LED transparent lens mask, comprising the following steps:

[0018] (1) Preparation of nanoscale cerium-doped zinc oxide Ce-ZnO quantum dots:

[0019] a) In a 250 mL three-necked round-bottom flask, add 150 mL of anhydrous ethanol;

[0020] b) Add 10.0-12.0 mmol of zinc acetate dihydrate and 0.2-0.4 mmol of cerium(III) acetate hydrate, and stir to dissolve;

[0021] c) In another beaker, dissolve 20-24 mmol of sodium hydroxide in 50 mL of anhydrous ethanol;

[0022] d) Slowly add sodium hydroxide solution into acetate solution with constant pressure dropping funnel at the speed of 2-3 mL / min under ice bath at 0-5 °C and nitrogen protection, while keeping stirring at 900-1100 rpm;

[0023] e) After the completion of dropping, increase the reaction temperature to 25±2 °C and continue stirring for 3 hours;

[0024] f) Separate the product by centrifugation at 7000-8000 rpm for 15 minutes and wash with anhydrous ethanol and deionized water for 3 times respectively;

[0025] g) Dry the obtained product in vacuum oven at 80±2 °C for 10 hours, keeping the vacuum degree at 0.1-0.05 MPa;

[0026] (2) Preparation of photochromic spiropyran derivative modified silica nanoparticles:

[0027] a) In a 500 mL three-necked round-bottom flask, add 250 mL anhydrous ethanol, 15 mL ammonia water (28-30%) and 7 mL deionized water;

[0028] b) Slowly add 20 mL tetraethyl orthosilicate (TEOS) with constant pressure dropping funnel at the speed of 1-2 mL / min under nitrogen protection and stirring at 600-700 rpm, and react at room temperature (25±2 °C) for 5 hours;

[0029] c) Separate the silica nanoparticles by centrifugation at 7000-8000 rpm for 15 minutes and wash with anhydrous ethanol for 3 times;

[0030] d) Disperse the nanoparticles in 250 mL anhydrous toluene, add 3 g (3-glycidyloxypropyl)trimethoxysilane, and react at 80±2 °C under reflux for 10 hours under nitrogen protection;

[0031] e) Separate the product by centrifugation at 7000-8000 rpm for 15 minutes and wash with anhydrous toluene and anhydrous ethanol for 3 times respectively;

[0032] f) Disperse the modified nanoparticles in 250 mL anhydrous N,N-dimethylformamide (DMF);

[0033] g) Add 2 g 1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-(2H)-indole] and 0.2 g p-toluenesulfonic acid;

[0034] h) React at 85±2 °C for 18 hours under nitrogen protection;

[0035] i) Separate the product by centrifugation at 7000-8000 rpm for 15 minutes and wash with DMF and anhydrous ethanol for 3 times respectively;

[0036] j) The resulting product is placed in a vacuum oven at 60 ± 2 °C for 18 hours, with a vacuum degree of 0.1-0.05 MPa;

[0037] (3) Preparation of the composite material:

[0038] a) In a 1 L three-necked round-bottom flask, 500 mL of tetrahydrofuran (THF) is added;

[0039] b) 85 parts by weight of poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA) is added, and dissolved at 25 ± 2 °C for 5 hours with stirring at a speed of 300-400 rpm;

[0040] c) Under the condition of ultrasonic dispersion (power 40-50 W, frequency 40 kHz), 1.5 parts by weight of Ce-ZnO quantum dot suspension (previously dispersed in 50 mL of THF) is slowly added, and ultrasonic dispersion is continued for 45 minutes;

[0041] d) 2 parts by weight of photochromic spiropyran derivative modified silica nanoparticle suspension (previously dispersed in 50 mL of THF) is added, and ultrasonic dispersion is continued for 45 minutes;

[0042] e) 7.5 parts by weight of random ethylene-methyl acrylate-glycidyl methacrylate terpolymer is added, and dissolved at 25 ± 2 °C for 3 hours with stirring at a speed of 300-400 rpm;

[0043] f) Finally, 2 parts by weight of hyperbranched fluorinated polyether is added, and stirred uniformly at 25 ± 2 °C for 3 hours at a speed of 300-400 rpm;

[0044] g) The resulting uniform solution is poured into a polytetrafluoroethylene mold of 40 cm x 40 cm x 1 cm;

[0045] h) In a fume hood, the solvent is slowly evaporated at 25 ± 2 °C for 36 hours;

[0046] i) The initially formed film is placed in a vacuum oven at 70 ± 2 °C for 18 hours, with a vacuum degree of 0.1-0.05 MPa, to remove residual solvents.

[0047] Specifically, the following hot press forming step is also included:

[0048] a) The dried composite film is cut into a square of 30 cm x 30 cm;

[0049] b) The film is placed between two polished stainless steel plates (surface roughness Ra ≤ 0.2 μm) of 40 cm x 40 cm in size and 1 cm in thickness;

[0050] c) Place the entire assembly into the hot press;

[0051] d) Increase the temperature to 180±2℃ at a rate of 8℃ / min;

[0052] e) Apply a pressure of 20±1MPa at 180±2℃ and maintain for 45 minutes;

[0053] f) Maintain pressure and slowly cool to 25±2℃ at a rate of 2℃ / min.

[0054] Specifically, it also includes the following surface treatment steps:

[0055] a) Place the hot-pressed mask in a sealed chamber filled with nitrogen (nitrogen purity ≥ 99.99%).

[0056] b) Use a UV lamp with a wavelength of 365±5nm and a light intensity of 7.5±0.5mW / cm². 2 ;

[0057] c) Irradiate at 30±2℃ for 30 minutes to activate the photochromic groups on the surface.

[0058] Specifically, it also includes the following post-processing steps:

[0059] a) Prepare a 3wt% hydrofluoric acid solution (using 40% hydrofluoric acid);

[0060] b) Immerse the mask in hydrofluoric acid solution for 30±2 seconds;

[0061] c) Immediately rinse with deionized water (conductivity ≤1μS / cm) for 4 minutes;

[0062] d) Wipe the surface with a cleanroom-grade lint-free cloth (Class 100 cleanroom standard);

[0063] e) Dry in a vacuum oven at 70±2℃ for 3 hours, maintaining a vacuum level of 0.1-0.05MPa.

[0064] The present invention has the following beneficial effects:

[0065] First, using poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA) as the matrix not only ensures high light transmittance but also provides active sites through the PGMA blocks, which is beneficial for the uniform dispersion and chemical bonding of other functional components. Second, the introduction of nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots, utilizing their unique band structure and the synergistic effect of cerium, achieves efficient UV blocking and photostability. Furthermore, the addition of the random ethylene-methyl methacrylate-glycidyl methacrylate terpolymer forms a dynamic covalent network, endowing the material with excellent self-healing capabilities. In addition, the introduction of photochromic spiropyran derivative-modified silica nanoparticles achieves intelligent anti-glare function through photoinduced molecular configuration changes. Finally, the addition of hyperbranched fluorinated polyether creates a superhydrophobic effect similar to the surface of a lotus leaf by forming a nanoscale phase-separated structure on the material surface, greatly improving the material's self-cleaning ability.

[0066] This multi-component synergistic design not only solves the performance trade-offs that may arise from improvements in a single function, but also generates a series of unexpected synergistic effects through the interactions between the components. For example, the interaction between the PGMA block of PMMA-b-PGMA and Ce-ZnO quantum dots not only enhances the material's UV resistance but also improves its mechanical strength. The interaction between photochromic spiropyran-modified silica nanoparticles and the PGMA block significantly improves the response speed and dimming range of the intelligent anti-glare technology.

[0067] At the molecular level, this synergistic effect stems from the carefully designed molecular structure and functional group distribution. The epoxy groups in PMMA-b-PGMA provide chemical bonding sites for other components, while the hydroxyl groups on the Ce-ZnO quantum dot surface can undergo ring-opening reactions with the epoxy groups to form stable chemical bonds. The glycidyl methacrylate units in the random terpolymer not only form covalent bonds with the matrix but also participate in the construction of a dynamic cross-linking network. The photochromic spiropyran molecule forms a stable bond with the silica nanoparticle surface through a silane coupling agent, ensuring its uniform distribution and durable performance within the matrix. The hyperbranched structure and terminal hydroxyl groups of the hyperbranched fluorinated polyether enable it to form physical entanglement and chemical bonds with the matrix, while simultaneously forming low surface energy nanostructures on the surface.

[0068] This multi-level, multi-scale synergistic mechanism not only ensures the effective functioning of the material but also produces performance improvements beyond expectations. For example, after 2000 hours of accelerated aging under a xenon lamp, the material's light transmittance decreased by only 1.6%, far superior to traditional materials; its self-healing speed was significantly accelerated, capable of repairing 100μm wide scratches within 2 hours; its intelligent dimming range expanded to 30%, 20-50% higher than expected; and its water contact angle reached 158°, demonstrating excellent self-cleaning performance.

[0069] In summary, this invention, through a deep understanding of cutting-edge knowledge in materials science, optics, polymer chemistry, and nanotechnology, has successfully developed a multifunctional, synergistic, and high-performance transparent lens cover material for highway LEDs. This innovation not only solves multiple challenges faced by existing technologies but also provides new ideas and methods for developing a new generation of intelligent, durable, and transparent protective materials. The success of this invention will significantly improve the lifespan and information transmission efficiency of highway LED displays, making a significant contribution to improving road safety and traffic efficiency. Furthermore, this multifunctional synergistic design concept and method are also expected to find wide applications in architectural glass, automotive windshields, and other fields, driving technological progress in related industries. Detailed Implementation

[0070] In the highway LED transparent lens cover of this invention, poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA), trade name: Plexiglas VS-UVT, grade: Plexiglas VS-UVT 100, has a molecular weight of Mn = 75,000±5,000 g / mol, a block ratio of PMMA:PGMA = 7.5:2.5 to 8.5:1.5, a transmittance of ≥92% (3mm thickness, 550nm wavelength), a refractive index of 1.49±0.01 (20℃, 589nm), and a glass transition temperature of 105±2℃; random ethylene-methyl methacrylate-glycidyl methacrylate terpolymer is used as a self-healing and toughening agent, trade name: AX8900, GMA content 8±0.5wt%, melt index (190℃ / 2.16kg) 6-8g / 10min; density 0.94±0.01g / cm³ 3 Vicat softening point: 60±2℃; Elongation at break: >700%; Hyperbranched fluorinated polyether, trade name: Z-Tetraol has a molecular weight of Mn = 2200±200 g / mol, a hydroxyl value of 160±5 mg KOH / g, a viscosity (20℃) of 80-120 cSt, a surface tension (20℃) of 25±2 mN / m, and a thermal decomposition temperature >290℃. Its structural formula is as follows:

[0071]

[0072] Example 1

[0073] This embodiment provides a transparent LED lens cover for highways and its preparation method. The formulation, by weight, includes the following components:

[0074] 80 parts of poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA);

[0075] 0.5 parts of nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots;

[0076] Five parts of random ethylene-methyl acrylate-glycidyl methacrylate terpolymer;

[0077] One portion of photochromic spiropyran derivative-modified silica nanoparticles;

[0078] 1 part hyperbranched fluorinated polyether.

[0079] The PMMA-b-PGMA has a molecular weight of 70,000 g / mol and a block ratio of PMMA:PGMA of 7.5:2.5. The Ce-ZnO quantum dots have a particle size of 5 nm and a cerium doping content of 1 mol%. The random terpolymer contains 7.5 wt% glycidyl methacrylate and has a melt index (190℃ / 2.16 kg) of 6 g / 10 min. The photochromic spiropyran-modified silica nanoparticles have a particle size of 20 nm and a spiropyran modification density of 0.5 μmol / m³. 2 The hyperbranched fluorinated polyether has a molecular weight of 2000 g / mol and a hydroxyl value of 155 mg KOH / g.

[0080] The method for preparing the LED transparent lens cover for highways includes the following steps:

[0081] First, nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots were prepared. In a 250 mL three-necked round-bottom flask, 150 mL of anhydrous ethanol was added, followed by 10.0 mmol of zinc acetate dihydrate and 0.2 mmol of cerium(III) acetate hydrate, and the mixture was stirred until dissolved. In another beaker, 20 mmol of sodium hydroxide was dissolved in 50 mL of anhydrous ethanol. Under a nitrogen atmosphere and in an ice bath at 0 °C, the sodium hydroxide solution was slowly added dropwise to the acetate solution at a rate of 2 mL / min using a constant-pressure dropping funnel, while stirring at 900 rpm. After the addition was complete, the reaction temperature was raised to 25 °C, and the reaction was continued with stirring for 3 hours. Subsequently, the product was separated by centrifugation at 7000 rpm for 15 minutes and washed three times each with anhydrous ethanol and deionized water. Finally, the obtained product was dried in a vacuum oven at 80 °C for 10 hours, maintaining a vacuum of 0.1 MPa.

[0082] Next, photochromic spiropyran derivative-modified silica nanoparticles were prepared. In a 500 mL three-necked round-bottom flask, 250 mL of anhydrous ethanol, 15 mL of ammonia (28-30%), and 7 mL of deionized water were added. Under nitrogen protection, the mixture was stirred at 600 rpm, and 20 mL of tetraethyl orthosilicate (TEOS) was slowly added dropwise at a rate of 1 mL / min using a constant-pressure dropping funnel. The reaction was carried out at room temperature (25 °C) for 5 hours. Then, the silica nanoparticles were separated by centrifugation at 7000 rpm for 15 minutes and washed three times with anhydrous ethanol. The nanoparticles were dispersed in 250 mL of anhydrous toluene, and 3 g of (3-glycidylpropoxy)trimethoxysilane was added. The mixture was refluxed at 80 °C for 10 hours under nitrogen protection. The product was again separated by centrifugation at 7000 rpm for 15 minutes and washed three times each with anhydrous toluene and anhydrous ethanol. The modified nanoparticles were dispersed in 250 mL of anhydrous N,N-dimethylformamide (DMF), and 2 g of 1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-(2H)-indole] and 0.2 g of p-toluenesulfonic acid were added. The reaction was carried out at 85 °C for 18 hours under nitrogen protection. Finally, the product was separated by centrifugation at 7000 rpm for 15 minutes, washed three times each with DMF and anhydrous ethanol, and dried in a vacuum oven at 60 °C for 18 hours, maintaining a vacuum of 0.1 MPa. The chemical structure of 1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-(2H)-indole] is as follows:

[0083]

[0084] Next, the composite material was prepared. In a 1L three-necked round-bottom flask, 500 mL of tetrahydrofuran (THF) was added, followed by 80 parts by weight of PMMA-b-PGMA. The mixture was stirred and dissolved at 25°C for 5 hours at a stirring speed of 300 rpm. Under ultrasonic dispersion (40 W power, 40 kHz frequency), 0.5 parts by weight of Ce-ZnO quantum dot suspension (pre-dispersed in 50 mL THF) was slowly added, and ultrasonic dispersion was maintained for 45 minutes. Subsequently, 1 part by weight of photochromic spiropyran derivative-modified silica nanoparticle suspension (pre-dispersed in 50 mL THF) was added, and ultrasonic dispersion was continued for 45 minutes. Then, 5 parts by weight of atactic ethylene-methyl acrylate-glycidyl methacrylate terpolymer was added, and the mixture was stirred and dissolved at 25°C for 3 hours at a stirring speed of 300 rpm. Finally, 1 part by weight of hyperbranched fluorinated polyether was added, and the mixture was stirred evenly at 25°C for 3 hours at a stirring speed of 300 rpm. The obtained homogeneous solution was poured into a 40cm×40cm×1cm polytetrafluoroethylene mold, and the solvent was slowly evaporated at 25°C for 36 hours in a fume hood. The preliminarily formed film was then placed in a 70°C vacuum oven to dry for 18 hours, with the vacuum level maintained at 0.1MPa, to remove residual solvent.

[0085] The hot pressing process is as follows: Cut the dried composite film into 30cm × 30cm squares and place them between two 40cm × 40cm, 1cm thick polished stainless steel plates (surface roughness Ra ≤ 0.2μm). Place the entire assembly into a hot press and heat it to 180°C at a rate of 8°C / min. At 180°C, apply a pressure of 20MPa and hold for 45 minutes. Maintain the pressure and slowly cool to 25°C at a rate of 2°C / min.

[0086] The surface treatment steps are as follows: The thermo-pressed mask is placed in a sealed chamber filled with nitrogen (nitrogen purity ≥ 99.99%). A UV lamp with a wavelength of 365nm and a light intensity of 7.5mW / cm² is used. 2 Irradiation at 30°C for 30 minutes activates the photochromic groups on the surface.

[0087] Finally, post-processing steps are performed: Prepare a 3wt% hydrofluoric acid solution (using 40% hydrofluoric acid). Immerse the mask in the hydrofluoric acid solution for 30 seconds, then immediately rinse with deionized water (conductivity ≤1μS / cm) for 4 minutes. Wipe the surface with a lint-free cloth in a Class 100 cleanroom, and dry in a 70℃ vacuum oven for 3 hours, maintaining a vacuum level of 0.1MPa.

[0088] Preferably, in the embodiments of the present invention, PMMA-b-PGMA, as the matrix material, not only provides excellent light transmittance but also enhances the overall performance of the material by forming chemical bonds with other components through the epoxy groups of the PGMA blocks. Ce-ZnO quantum dots, as an anti-UV additive, ensure uniform dispersion at the nanoscale while maintaining the material's high light transmittance. Random terpolymers provide self-healing capabilities and toughening effects through a dynamic covalent bond network, significantly improving the material's durability. Photochromic spiropyran-modified silica nanoparticles achieve intelligent anti-glare function, automatically adjusting light transmittance under strong light, thus improving driving safety. The introduction of hyperbranched fluorinated polyethers endows the material with excellent self-cleaning properties, reducing maintenance costs.

[0089] Example 2

[0090] This embodiment provides another transparent LED lens cover for highways and its preparation method. The formulation, by weight, comprises the following components:

[0091] 85 parts of poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA);

[0092] 1.25 nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots;

[0093] 7.5 parts of random ethylene-methyl acrylate-glycidyl methacrylate terpolymer;

[0094] Two photochromic spiropyran derivatives-modified silica nanoparticles;

[0095] Two parts of hyperbranched fluorinated polyether.

[0096] The PMMA-b-PGMA has a molecular weight of 75,000 g / mol and a block ratio of PMMA:PGMA of 8:2. The Ce-ZnO quantum dots have a particle size of 7.5 nm and a cerium doping content of 3 mol%. The random terpolymer contains 8 wt% glycidyl methacrylate and has a melt index (190℃ / 2.16 kg) of 7 g / 10 min. The photochromic spiropyran-modified silica nanoparticles have a particle size of 35 nm and a spiropyran modification density of 0.75 μmol / m³. 2 The hyperbranched fluorinated polyether has a molecular weight of 2500 g / mol and a hydroxyl value of 165 mg KOH / g.

[0097] The method for preparing the LED transparent lens cover for highways includes the following steps:

[0098] First, nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots were prepared. In a 250 mL three-necked round-bottom flask, 150 mL of anhydrous ethanol was added, followed by 11.0 mmol of zinc acetate dihydrate and 0.3 mmol of cerium(III) acetate hydrate, and the mixture was stirred until dissolved. In another beaker, 22 mmol of sodium hydroxide was dissolved in 50 mL of anhydrous ethanol. Under nitrogen protection and an ice bath at 2.5 °C, the sodium hydroxide solution was slowly added dropwise to the acetate solution using a constant-pressure dropping funnel at a rate of 2.5 mL / min, while stirring at 1000 rpm. After the addition was complete, the reaction temperature was raised to 25 °C, and the reaction was continued with stirring for 3 hours. Subsequently, the product was separated by centrifugation at 7500 rpm for 15 minutes and washed three times each with anhydrous ethanol and deionized water. Finally, the obtained product was dried in a vacuum oven at 80 °C for 10 hours, maintaining a vacuum of 0.075 MPa.

[0099] Next, photochromic spiropyran derivative-modified silica nanoparticles were prepared. In a 500 mL three-necked round-bottom flask, 250 mL of anhydrous ethanol, 15 mL of ammonia (28-30%), and 7 mL of deionized water were added. Under nitrogen protection, the mixture was stirred at 650 rpm, and 20 mL of tetraethyl orthosilicate (TEOS) was slowly added dropwise at a rate of 1.5 mL / min using a constant-pressure dropping funnel. The reaction was carried out at room temperature (25 °C) for 5 hours. Then, the silica nanoparticles were separated by centrifugation at 7500 rpm for 15 minutes and washed three times with anhydrous ethanol. The nanoparticles were dispersed in 250 mL of anhydrous toluene, and 3 g of (3-glycidylpropoxy)trimethoxysilane was added. The mixture was refluxed at 80 °C for 10 hours under nitrogen protection. The product was again separated by centrifugation at 7500 rpm for 15 minutes and washed three times each with anhydrous toluene and anhydrous ethanol. The modified nanoparticles were dispersed in 250 mL of anhydrous N,N-dimethylformamide (DMF), and 2 g of 1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-(2H)-indole] and 0.2 g of p-toluenesulfonic acid were added. The reaction was carried out at 85 °C for 18 hours under nitrogen protection. Finally, the product was separated by centrifugation at 7500 rpm for 15 minutes, washed three times each with DMF and anhydrous ethanol, and dried in a vacuum oven at 60 °C for 18 hours, maintaining a vacuum of 0.075 MPa.

[0100] Next, the composite material was prepared. In a 1L three-necked round-bottom flask, 500 mL of tetrahydrofuran (THF) was added, followed by 85 parts by weight of PMMA-b-PGMA. The mixture was stirred and dissolved at 25°C for 5 hours at a stirring speed of 350 rpm. Under ultrasonic dispersion (45 W power, 40 kHz frequency), 1.25 parts by weight of Ce-ZnO quantum dot suspension (pre-dispersed in 50 mL THF) was slowly added, and ultrasonic dispersion was maintained for 45 minutes. Subsequently, 2 parts by weight of a photochromic spiropyran derivative-modified silica nanoparticle suspension (pre-dispersed in 50 mL THF) was added, and ultrasonic dispersion was continued for 45 minutes. Then, 7.5 parts by weight of a random ethylene-methyl acrylate-glycidyl methacrylate terpolymer was added, and the mixture was stirred and dissolved at 25°C for 3 hours at a stirring speed of 350 rpm. Finally, 2 parts by weight of hyperbranched fluorinated polyether was added, and the mixture was stirred evenly at 25°C for 3 hours at a stirring speed of 350 rpm. The obtained homogeneous solution was poured into a 40cm×40cm×1cm polytetrafluoroethylene mold, and the solvent was slowly evaporated at 25°C for 36 hours in a fume hood. The preliminarily formed film was then placed in a 75°C vacuum oven to dry for 18 hours, with the vacuum level maintained at 0.075MPa, to remove residual solvent.

[0101] The hot pressing process is as follows: Cut the dried composite film into 30cm × 30cm squares and place them between two 40cm × 40cm, 1cm thick polished stainless steel plates (surface roughness Ra ≤ 0.2μm). Place the entire assembly into a hot press and heat to 185°C at a rate of 9°C / min. At 185°C, apply a pressure of 22.5MPa and hold for 52.5 minutes. Maintain the pressure and slowly cool to 25°C at a rate of 2.5°C / min.

[0102] The surface treatment steps are as follows: The thermo-pressed mask is placed in a sealed chamber filled with nitrogen (nitrogen purity ≥ 99.99%). A UV lamp with a wavelength of 365nm and a light intensity of 8.75mW / cm² is used. 2 Irradiation at 35°C for 35 minutes activates the photochromic groups on the surface.

[0103] Finally, post-processing steps are performed: Prepare a 3.5 wt% hydrofluoric acid solution (using 40% hydrofluoric acid). Immerse the mask in the hydrofluoric acid solution for 35 seconds, then immediately rinse with deionized water (conductivity ≤1 μS / cm) for 4.5 minutes. Wipe the surface with a lint-free cloth in a Class 100 cleanroom, and dry in a vacuum oven at 75°C for 3.5 hours, maintaining a vacuum level of 0.075 MPa.

[0104] Example 3

[0105] This embodiment provides a third type of transparent LED lens cover for highways and its preparation method. The formulation, by weight, includes the following components:

[0106] 90 parts of poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA);

[0107] 2.0 parts of nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots;

[0108] 10 parts random ethylene-methyl acrylate-glycidyl methacrylate terpolymer;

[0109] Three photochromic spiropyran derivatives modified silica nanoparticles;

[0110] 3 parts hyperbranched fluorinated polyether.

[0111] The PMMA-b-PGMA has a molecular weight of 80,000 g / mol and a block ratio of PMMA:PGMA of 8.5:1.5. The Ce-ZnO quantum dots have a particle size of 10 nm and a cerium doping content of 5 mol%. The random terpolymer contains 8.5 wt% glycidyl methacrylate and has a melt index (190℃ / 2.16 kg) of 8 g / 10 min. The photochromic spiropyran-modified silica nanoparticles have a particle size of 50 nm and a spiropyran modification density of 1.0 μmol / m³. 2 The hyperbranched fluorinated polyether has a molecular weight of 3000 g / mol and a hydroxyl value of 175 mg KOH / g.

[0112] The method for preparing the LED transparent lens cover for highways includes the following steps:

[0113] First, nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots were prepared. In a 250 mL three-necked round-bottom flask, 150 mL of anhydrous ethanol was added, followed by 12.0 mmol of zinc acetate dihydrate and 0.4 mmol of cerium(III) acetate hydrate, and the mixture was stirred until dissolved. In another beaker, 24 mmol of sodium hydroxide was dissolved in 50 mL of anhydrous ethanol. Under a nitrogen atmosphere and in an ice bath at 5 °C, the sodium hydroxide solution was slowly added dropwise to the acetate solution using a constant-pressure dropping funnel at a rate of 3 mL / min, while stirring at 1100 rpm. After the addition was complete, the reaction temperature was raised to 25 °C, and the reaction was continued with stirring for 3 hours. Subsequently, the product was separated by centrifugation at 8000 rpm for 15 minutes and washed three times each with anhydrous ethanol and deionized water. Finally, the obtained product was dried in a vacuum oven at 80 °C for 10 hours, maintaining a vacuum of 0.05 MPa.

[0114] Next, photochromic spiropyran derivative-modified silica nanoparticles were prepared. In a 500 mL three-necked round-bottom flask, 250 mL of anhydrous ethanol, 15 mL of ammonia (28-30%), and 7 mL of deionized water were added. Under nitrogen protection, the mixture was stirred at 700 rpm, and 20 mL of tetraethyl orthosilicate (TEOS) was slowly added dropwise at a rate of 2 mL / min using a constant-pressure dropping funnel. The reaction was carried out at room temperature (25 °C) for 5 hours. Then, the silica nanoparticles were separated by centrifugation at 8000 rpm for 15 minutes and washed three times with anhydrous ethanol. The nanoparticles were dispersed in 250 mL of anhydrous toluene, and 3 g of (3-glycidylpropoxy)trimethoxysilane was added. The mixture was refluxed at 80 °C for 10 hours under nitrogen protection. The product was again separated by centrifugation at 8000 rpm for 15 minutes and washed three times each with anhydrous toluene and anhydrous ethanol. The modified nanoparticles were dispersed in 250 mL of anhydrous N,N-dimethylformamide (DMF), and 2 g of 1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-(2H)-indole] and 0.2 g of p-toluenesulfonic acid were added. The reaction was carried out at 85 °C for 18 hours under nitrogen protection. Finally, the product was separated by centrifugation at 8000 rpm for 15 minutes, washed three times each with DMF and anhydrous ethanol, and dried in a vacuum oven at 60 °C for 18 hours, maintaining a vacuum of 0.05 MPa.

[0115] Next, the composite material was prepared. In a 1L three-necked round-bottom flask, 500 mL of tetrahydrofuran (THF) was added, followed by 90 parts by weight of PMMA-b-PGMA. The mixture was stirred and dissolved at 25°C for 5 hours at a stirring speed of 400 rpm. Under ultrasonic dispersion (50 W power, 40 kHz frequency), 2.0 parts by weight of Ce-ZnO quantum dot suspension (pre-dispersed in 50 mL THF) was slowly added, and ultrasonic dispersion was maintained for 45 minutes. Subsequently, 3 parts by weight of photochromic spiropyran derivative-modified silica nanoparticle suspension (pre-dispersed in 50 mL THF) was added, and ultrasonic dispersion was continued for 45 minutes. Then, 10 parts by weight of random ethylene-methyl acrylate-glycidyl methacrylate terpolymer was added, and the mixture was stirred and dissolved at 25°C for 3 hours at a stirring speed of 400 rpm. Finally, 3 parts by weight of hyperbranched fluorinated polyether was added, and the mixture was stirred evenly at 25°C for 3 hours at a stirring speed of 400 rpm. The obtained homogeneous solution was poured into a 40cm×40cm×1cm polytetrafluoroethylene mold, and the solvent was slowly evaporated at 25°C for 36 hours in a fume hood. The preliminarily formed film was then placed in an 80°C vacuum oven to dry for 18 hours, with the vacuum level maintained at 0.05MPa, to remove residual solvent.

[0116] The hot pressing process is as follows: Cut the dried composite film into 30cm × 30cm squares and place them between two 40cm × 40cm, 1cm thick polished stainless steel plates (surface roughness Ra ≤ 0.2μm). Place the entire assembly into a hot press and heat it to 190°C at a rate of 10°C / min. At 190°C, apply a pressure of 25MPa and maintain it for 60 minutes. Maintain the pressure and slowly cool it to 25°C at a rate of 3°C / min.

[0117] The surface treatment steps are as follows: The thermo-pressed mask is placed in a sealed chamber filled with nitrogen (nitrogen purity ≥ 99.99%). A UV lamp with a wavelength of 365nm and a light intensity of 10mW / cm² is used. 2 Irradiation at 40°C for 40 minutes activates the photochromic groups on the surface.

[0118] Finally, post-processing steps are performed: Prepare a 4wt% hydrofluoric acid solution (using 40% hydrofluoric acid). Immerse the mask in the hydrofluoric acid solution for 40 seconds, then immediately rinse with deionized water (conductivity ≤1μS / cm) for 5 minutes. Wipe the surface with a lint-free cloth in a Class 100 cleanroom, and dry in an 80℃ vacuum oven for 4 hours, maintaining a vacuum level of 0.05MPa.

[0119] Example 4

[0120] This embodiment provides a fourth type of transparent LED lens cover for highways and its preparation method. The formulation, by weight, includes the following components:

[0121] 87.5 parts of poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA);

[0122] 1.75 nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots;

[0123] 8.75 parts of random ethylene-methyl acrylate-glycidyl methacrylate terpolymer;

[0124] 2.5 parts of photochromic spiropyran derivative-modified silica nanoparticles;

[0125] 2.5 parts hyperbranched fluorinated polyether.

[0126] The PMMA-b-PGMA has a molecular weight of 77,500 g / mol and a block ratio of PMMA:PGMA of 8.25:1.75. The Ce-ZnO quantum dots have a particle size of 8.75 nm and a cerium doping content of 4 mol%. The random terpolymer contains 8.25 wt% glycidyl methacrylate and has a melt index (190℃ / 2.16 kg) of 7.5 g / 10 min. The photochromic spiropyran-modified silica nanoparticles have a particle size of 42.5 nm and a spiropyran modification density of 0.875 μmol / m³. 2 The hyperbranched fluorinated polyether has a molecular weight of 2750 g / mol and a hydroxyl value of 170 mg KOH / g.

[0127] The method for preparing the LED transparent lens cover for highways includes the following steps:

[0128] First, nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots were prepared. In a 250 mL three-necked round-bottom flask, 150 mL of anhydrous ethanol was added, followed by 11.5 mmol of zinc acetate dihydrate and 0.35 mmol of cerium(III) acetate hydrate, and the mixture was stirred until dissolved. In another beaker, 23 mmol of sodium hydroxide was dissolved in 50 mL of anhydrous ethanol. Under nitrogen protection and in an ice bath at 3.75 °C, the sodium hydroxide solution was slowly added dropwise to the acetate solution using a constant-pressure dropping funnel at a rate of 2.75 mL / min, while stirring at 1050 rpm. After the addition was complete, the reaction temperature was raised to 25 °C, and the reaction was continued with stirring for 3 hours. Subsequently, the product was separated by centrifugation at 7750 rpm for 15 minutes and washed three times each with anhydrous ethanol and deionized water. Finally, the obtained product was dried in a vacuum oven at 80 °C for 10 hours, maintaining a vacuum of 0.0625 MPa.

[0129] Next, photochromic spiropyran derivative-modified silica nanoparticles were prepared. In a 500 mL three-necked round-bottom flask, 250 mL of anhydrous ethanol, 15 mL of ammonia (28-30%), and 7 mL of deionized water were added. Under nitrogen protection, the mixture was stirred at 675 rpm, and 20 mL of tetraethyl orthosilicate (TEOS) was slowly added dropwise at a rate of 1.75 mL / min using a constant-pressure dropping funnel. The reaction was carried out at room temperature (25 °C) for 5 hours. Then, the silica nanoparticles were separated by centrifugation at 7750 rpm for 15 minutes and washed three times with anhydrous ethanol. The nanoparticles were dispersed in 250 mL of anhydrous toluene, and 3 g of (3-glycidylpropoxy)trimethoxysilane was added. The mixture was refluxed at 80 °C for 10 hours under nitrogen protection. The product was again separated by centrifugation at 7750 rpm for 15 minutes and washed three times each with anhydrous toluene and anhydrous ethanol. The modified nanoparticles were dispersed in 250 mL of anhydrous N,N-dimethylformamide (DMF), and 2 g of 1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-(2H)-indole] and 0.2 g of p-toluenesulfonic acid were added. The reaction was carried out at 85 °C for 18 hours under nitrogen protection. Finally, the product was separated by centrifugation at 7750 rpm for 15 minutes, washed three times each with DMF and anhydrous ethanol, and dried in a vacuum oven at 60 °C for 18 hours, maintaining a vacuum of 0.0625 MPa.

[0130] Next, the composite material was prepared. In a 1L three-necked round-bottom flask, 500 mL of tetrahydrofuran (THF) was added, followed by 87.5 parts by weight of PMMA-b-PGMA. The mixture was stirred and dissolved at 25°C for 5 hours at a stirring speed of 375 rpm. Under ultrasonic dispersion (power 47.5 W, frequency 40 kHz), 1.75 parts by weight of Ce-ZnO quantum dot suspension (pre-dispersed in 50 mL THF) was slowly added, and ultrasonic dispersion was maintained for 45 minutes. Subsequently, 2.5 parts by weight of a photochromic spiropyran derivative-modified silica nanoparticle suspension (pre-dispersed in 50 mL THF) was added, and ultrasonic dispersion was continued for 45 minutes. Then, 8.75 parts by weight of a random ethylene-methyl acrylate-glycidyl methacrylate terpolymer was added, and the mixture was stirred and dissolved at 25°C for 3 hours at a stirring speed of 375 rpm. Finally, 2.5 parts by weight of hyperbranched fluorinated polyether was added, and the mixture was stirred evenly at 25°C for 3 hours at a stirring speed of 375 rpm. The obtained homogeneous solution was poured into a 40cm×40cm×1cm polytetrafluoroethylene mold, and the solvent was slowly evaporated at 25°C for 36 hours in a fume hood. The preliminarily formed film was then placed in a vacuum oven at 77.5°C for 18 hours, with the vacuum level maintained at 0.0625MPa, to remove residual solvent.

[0131] The hot pressing process is as follows: The dried composite film is cut into 30cm × 30cm squares and placed between two 40cm × 40cm, 1cm thick polished stainless steel plates (surface roughness Ra ≤ 0.2μm). The entire assembly is placed in a hot press and heated to 187.5℃ at a rate of 9.5℃ / min. At 187.5℃, a pressure of 23.75MPa is applied and maintained for 56.25 minutes. The pressure is maintained while the assembly is slowly cooled to 25℃ at a rate of 2.75℃ / min.

[0132] The surface treatment steps are as follows: The thermo-pressed mask is placed in a sealed chamber filled with nitrogen (nitrogen purity ≥ 99.99%). A UV lamp with a wavelength of 365nm and a light intensity of 9.375mW / cm² is used. 2 Irradiation at 37.5℃ for 37.5 minutes activates the photochromic groups on the surface.

[0133] Finally, post-processing steps are performed: Prepare a 3.75 wt% hydrofluoric acid solution (using 40% hydrofluoric acid). Immerse the mask in the hydrofluoric acid solution for 37.5 seconds, then immediately rinse with deionized water (conductivity ≤1 μS / cm) for 4.75 minutes. Wipe the surface with a lint-free cloth in a Class 100 cleanroom, and dry in a vacuum oven at 77.5℃ for 3.75 hours, maintaining a vacuum level of 0.0625 MPa.

[0134] Comparative Example 1

[0135] This comparative example aims to verify the importance of the PMMA-b-PGMA block copolymer in this invention. The formulation, by weight, comprises the following components:

[0136] 80 parts polymethyl methacrylate (PMMA);

[0137] 0.5 parts of nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots;

[0138] Five parts of random ethylene-methyl acrylate-glycidyl methacrylate terpolymer;

[0139] One portion of photochromic spiropyran derivative-modified silica nanoparticles;

[0140] 1 part hyperbranched fluorinated polyether.

[0141] The molecular weight of PMMA is 70,000 g / mol. The parameters of other components are the same as in Example 1.

[0142] The method for preparing the LED transparent lens cover for highways includes the following steps:

[0143] First, the preparation method of Ce-ZnO quantum dots and photochromic spiropyran derivative-modified silica nanoparticles is the same as in Example 1.

[0144] Next, the composite material was prepared. In a 1L three-necked round-bottom flask, 500 mL of tetrahydrofuran (THF) was added, followed by 80 parts by weight of PMMA. The mixture was stirred at 25°C for 5 hours at a stirring speed of 300 rpm. Subsequent steps were the same as in Example 1.

[0145] The hot pressing, surface treatment, and post-treatment steps are the same as in Example 1.

[0146] Comparative analysis revealed that while replacing PMMA-b-PGMA with PMMA maintained high light transmittance, its weather resistance significantly decreased. After 2000 hours of accelerated aging under a xenon lamp, light transmittance decreased by over 10%. This is primarily because the PGMA blocks in PMMA-b-PGMA form chemical bonds with other components through epoxy groups, enhancing the overall stability of the material. Furthermore, the lack of PGMA blocks resulted in poorer dispersion of Ce-ZnO quantum dots and photochromic spiropyran-modified silica nanoparticles in the matrix, leading to reduced UV resistance and intelligent anti-glare effects.

[0147] Comparative Example 2

[0148] This comparative example aims to verify the importance of Ce-ZnO quantum dots in this invention. The formulation, by weight, comprises the following components:

[0149] 85 parts of poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA);

[0150] 1.25 parts titanium dioxide nanoparticles;

[0151] 7.5 parts of random ethylene-methyl acrylate-glycidyl methacrylate terpolymer;

[0152] Two photochromic spiropyran derivatives-modified silica nanoparticles;

[0153] Two parts of hyperbranched fluorinated polyether.

[0154] The titanium dioxide nanoparticles have a particle size of 7.5 nm. The parameters of other components are the same as in Example 2.

[0155] The method for preparing the LED transparent lens cover for highways includes the following steps:

[0156] First, titanium dioxide nanoparticles were prepared using the sol-gel method, with the specific steps as follows:

[0157] In a 250 mL three-necked round-bottom flask, 150 mL of anhydrous ethanol was added, followed by 10 mmol of tetrabutyl titanate, and the mixture was stirred to dissolve. Under a nitrogen atmosphere and in an ice bath at 0 °C, a mixture of 5 mL of deionized water and 1 mL of concentrated hydrochloric acid was slowly added dropwise. The reaction temperature was raised to 25 °C, and the reaction was continued with stirring for 3 hours. Subsequently, the product was separated by centrifugation at 7500 rpm for 15 minutes and washed three times with anhydrous ethanol. Finally, the obtained product was dried in a vacuum oven at 80 °C for 10 hours, maintaining a vacuum of 0.075 MPa.

[0158] The preparation methods for other components and the preparation steps for the composite material are the same as in Example 2.

[0159] Comparative analysis revealed that replacing Ce-ZnO quantum dots with titanium dioxide nanoparticles reduced the material's UV resistance. While titanium dioxide also possesses some UV blocking ability, its effect is inferior to that of Ce-ZnO quantum dots. At the same concentration, Ce-ZnO quantum dots can block over 98% of UV radiation, while titanium dioxide can only block approximately 90%. Furthermore, the lack of cerium doping also reduced the material's photostability under strong UV irradiation. This verifies that Ce-ZnO quantum dots provide highly efficient UV protection while simultaneously enhancing the material's photostability through cerium doping.

[0160] Comparative Example 3

[0161] This comparative example aims to verify the importance of the random ethylene-methyl acrylate-glycidyl methacrylate terpolymer in this invention. The formulation, by weight, comprises the following components:

[0162] 90 parts of poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA);

[0163] 2.0 parts of nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots;

[0164] 10 parts polymethyl methacrylate (PMMA);

[0165] Three photochromic spiropyran derivatives modified silica nanoparticles;

[0166] 3 parts hyperbranched fluorinated polyether.

[0167] The molecular weight of PMMA is 100,000 g / mol. The parameters of other components are the same as in Example 3.

[0168] The preparation method of the highway LED transparent lens cover is basically the same as that of Example 3, except that in the composite material preparation step, 10 parts by weight of PMMA is used to replace the random terpolymer.

[0169] Comparative analysis revealed that replacing the random terpolymer with PMMA resulted in the material losing its self-healing ability. Even minute scratches less than 100 μm wide failed to repair themselves during scratch testing. This is because the glycidyl methacrylate units in the random terpolymer form a dynamic covalent network, endowing the material with self-healing capabilities. Furthermore, the material's impact resistance also decreased due to the lack of toughening effect from the terpolymer. This validates the crucial role of random terpolymers in providing both self-healing and toughening properties.

[0170] Comparative Example 4

[0171] This comparative example aims to verify the importance of photochromic spiropyran derivative-modified silica nanoparticles in this invention. The formulation, by weight, comprises the following components:

[0172] 87.5 parts of poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA);

[0173] 1.75 nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots;

[0174] 8.75 parts of random ethylene-methyl acrylate-glycidyl methacrylate terpolymer;

[0175] 2.5 parts of unmodified silica nanoparticles;

[0176] 2.5 parts hyperbranched fluorinated polyether.

[0177] The unmodified silica nanoparticles had a particle size of 42.5 nm. The parameters of the other components were the same as in Example 4.

[0178] The preparation method of the highway LED transparent lens mask is basically the same as that of Example 4, except that the modification process of photochromic spiropyran derivative is omitted in the preparation step of silica nanoparticles.

[0179] Comparative analysis revealed that the material lost its intelligent anti-glare function when using unmodified silica nanoparticles. Under strong light, the material could not automatically adjust its transmittance, potentially leading to glare. This is because the photochromic spiropyran derivative undergoes structural changes under strong light stimulation, altering the material's optical properties. Furthermore, the lack of spiropyran modification reduced the compatibility of the silica nanoparticles with the matrix, resulting in a slight decrease in the material's mechanical strength. This validates the crucial role of photochromic spiropyran-modified silica nanoparticles in providing intelligent anti-glare functionality and enhancing the material's mechanical properties.

[0180] Comparative Example 5

[0181] This comparative example aims to verify the importance of hyperbranched fluorinated polyethers in this invention. The formulation comprises the following components by weight:

[0182] 80 parts of poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA);

[0183] 0.5 parts of nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots;

[0184] Five parts of random ethylene-methyl acrylate-glycidyl methacrylate terpolymer;

[0185] One portion of photochromic spiropyran derivative-modified silica nanoparticles;

[0186] 1 part polytetrafluoroethylene (PTFE) micro powder.

[0187] The average particle size of the PTFE micropowder is 1 μm. The parameters of other components are the same as in Example 1.

[0188] The preparation method of the highway LED transparent lens mask is basically the same as that of Example 1, except that in the composite material preparation step, 1 part by weight of PTFE micro powder is used to replace the hyperbranched fluorinated polyether.

[0189] Comparative analysis revealed that replacing hyperbranched fluorinated polyether with PTFE micropowder significantly reduced the material's self-cleaning effect. Although PTFE is also hydrophobic, its insolubility in organic solvents makes it difficult to form a homogeneous composite material with other components. Tests showed that the contact angle of the material surface was only around 120°, far lower than the over 150° achieved with hyperbranched fluorinated polyether. Furthermore, the larger size of the PTFE micropowder also reduced the material's light transmittance. This validates the crucial role of hyperbranched fluorinated polyether in providing excellent self-cleaning performance while maintaining high light transmittance.

[0190] Comparative Example 6

[0191] This comparative example aims to verify the synergistic effect between the components. The formulation, by weight, includes the following components:

[0192] 90 parts of poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer (PMMA-b-PGMA);

[0193] 2.0 parts of nanoscale cerium-doped zinc oxide (Ce-ZnO) quantum dots;

[0194] 10 parts random ethylene-methyl acrylate-glycidyl methacrylate terpolymer;

[0195] Three photochromic spiropyran derivatives modified silica nanoparticles;

[0196] 3 parts hyperbranched fluorinated polyether.

[0197] The parameters of each component are the same as in Example 3.

[0198] The preparation method of the highway LED transparent lens mask is basically the same as that of Example 3. However, in the composite material preparation step, each component is prepared separately and then mechanically mixed, rather than using a solution blending method.

[0199] The specific steps are as follows: First, each component is prepared according to the method in Example 3. Then, all components are placed in a high-speed mixer and dry-mixed at 5000 rpm for 10 minutes. Finally, the mixture is placed in a twin-screw extruder and extruded and granulated at 180°C to obtain the composite material. Subsequent hot pressing, surface treatment, and post-treatment steps are the same as in Example 3.

[0200] To comprehensively evaluate the performance of the highway LED transparent lens cover of this invention, a series of tests were designed, covering aspects such as optical performance, mechanical performance, weather resistance, and intelligent functions. These experiments not only verified the core innovations of this invention but also revealed the synergistic mechanism among the components.

[0201] First, transmittance was tested. A UV-Vis spectrophotometer (UV-2600, Shimadzu) was used to measure the transmittance of the samples within the wavelength range of 400-800 nm. The test conditions were room temperature 25℃ and relative humidity 50%. Each sample was tested three times, and the average value was taken.

[0202] Secondly, the UV resistance performance was evaluated. Accelerated aging tests were conducted using a xenon lamp aging chamber (Q-SUN Xe-3-HS, Q-Lab). The test conditions were: irradiance 0.55 W / m². 2 (340nm), blackboard temperature 65℃, relative humidity 50%. The transmittance change and yellowing index of the sample were measured every 500 hours.

[0203] Next, the self-healing ability of the material was tested. A 100 μm wide scratch was created on the sample surface using a scratch tester (CSM Instruments), and the recovery of the scratch was observed at 80°C. Micrographs were taken every 30 minutes for up to 4 hours.

[0204] Next, the intelligent anti-glare performance was evaluated. A self-made high-intensity light simulation device (with an adjustable LED light source and a maximum light intensity of 10000 cd / m²) was used. 2 The sample was irradiated, and the transmittance was monitored in real time using a spectrophotometer. Data was recorded every 5 seconds for 5 minutes.

[0205] Next, the self-cleaning effect of the material was tested. A contact angle meter (DSA100) was used. The contact angle of water droplets on the sample surface was measured. Simultaneously, the effect of rainwater scouring was simulated by tilting the sample at a 45° angle and dropping simulated rainwater (deionized water) from a height of 50 cm to observe the removal of stains (carbon black aqueous solution).

[0206] Finally, a comprehensive weather resistance test was conducted. The samples were placed at an outdoor testing station (located next to a highway), and their performance indicators were tested every 3 months for 1 year.

[0207] Based on the above tests, detailed test results for Examples 1-4 and Comparative Examples 1-6 were obtained. The following is a summary table of some key data:

[0208] Table 1: Results of optical performance and weather resistance tests for each sample

[0209]

[0210] Table 2: Functional performance test results of each sample

[0211]

[0212]

[0213] Based on the test results, Example 3 performed the best and can be considered the optimal embodiment of the present invention. While maintaining high light transmittance, it exhibited excellent UV resistance, rapid self-healing ability, sensitive intelligent anti-glare response, and outstanding self-cleaning effect.

[0214] In-depth analysis of the test data revealed that the present invention has the following unexpected technical effects:

[0215] 1. Ultra-long-lasting weather resistance: In Example 3, after 2000 hours of accelerated aging under a xenon lamp, the light transmittance only decreased.

[0216] The UV protection efficiency is 1.6%, far superior to traditional transparent protective materials. This is due to the synergistic effect of PMMA-b-PGMA and Ce-ZnO quantum dots, which not only effectively blocks ultraviolet rays but also inhibits photo-oxidation reactions within the material.

[0217] 2. Rapid self-healing capability: Example 3 can repair a 100μm wide scratch within 2 hours, a performance far exceeding expectations. This is because the dynamic covalent bond network formed by the random terpolymer is more uniformly distributed in the PMMA-b-PGMA matrix, greatly accelerating the self-healing process.

[0218] 3. Expanded intelligent dimming range: The transmittance adjustment range of Example 3 reaches 30%, which is wider than the expected 20-25%. This may be due to the synergistic effect between the photochromic spiropyran-modified silica nanoparticles and the PGMA block of PMMA-b-PGMA, which enhances the photoresponse sensitivity.

[0219] 4. Superhydrophobic self-cleaning effect: The water contact angle of Example 3 is as high as 158°, far exceeding that of ordinary hydrophobic materials. This is because the hyperbranched fluorinated polyether forms a nanoscale phase separation structure in the PMMA-b-PGMA matrix, creating a micro-nano structure similar to the surface of a lotus leaf, which greatly enhances the hydrophobicity.

[0220] 5. Synergistic effect of comprehensive performance: The interaction between the components does not weaken their respective functions, but rather produces an enhancing effect. For example, the introduction of Ce-ZnO quantum dots not only provides UV resistance, but also enhances the mechanical strength of the material through interaction with PGMA blocks.

[0221] These unexpected technical effects fully demonstrate the innovation of this invention in materials design. By carefully selecting the components and their proportions, and utilizing nanoscale phase separation and interfacial interactions, multifunctional synergistic effects are achieved. This provides new ideas for developing a new generation of high-performance transparent protective materials, which are not only suitable for highway LED displays, but also have the potential for wide application in architectural glass, automotive windshields, and other fields.

[0222] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for preparing a transparent LED lens cover for highways, characterized in that... The composite material comprises, by weight, the following components: 80-90 parts poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer; 0.5-2.0 parts nanoscale cerium-doped zinc oxide quantum dots; 5-10 parts random ethylene-methyl methacrylate-glycidyl methacrylate terpolymer; 1-3 parts photochromic spiropyran derivative-modified silica nanoparticles; and 1-3 parts hyperbranched fluorinated polyether. The preparation method includes the following steps for preparing the composite material: a) Add tetrahydrofuran solvent to a three-necked round-bottom flask; b) Add the poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer and stir to dissolve; c) Under ultrasonic dispersion conditions, the nanoscale cerium-doped zinc oxide quantum dot suspension was added and ultrasonically dispersed; d) Add the photochromic spiropyran derivative-modified silica nanoparticle suspension and continue ultrasonic dispersion; e) Add the random ethylene-methyl acrylate-glycidyl methacrylate terpolymer and stir to dissolve; f) Add the hyperbranched fluorinated polyether and stir until homogeneous; g) Pour the resulting homogeneous solution into the mold; h) Evaporate the solvent to obtain a thin film; i) Dry the film to remove residual solvent.

2. The preparation method according to claim 1, characterized in that... The poly(methyl methacrylate)-b-poly(glycidyl methacrylate) block copolymer has a molecular weight of 70,000-80,000 g / mol and a block ratio of PMMA:PGMA of 7.5:2.5 to 8.5:1.

5.

3. The preparation method according to claim 1, characterized in that... The nanoscale cerium-doped zinc oxide quantum dots have a particle size of 5-10 nm and a cerium doping amount of 1-5 mol.

4. The preparation method according to claim 1, characterized in that... The random ethylene-methyl acrylate-glycidyl methacrylate terpolymer contains 7.5-8.5 wt% glycidyl methacrylate and has a melt index of 6-8 g / 10min at 190℃ and 2.16 kg.

5. The preparation method according to claim 1, characterized in that... The photochromic spiropyran derivative-modified silica nanoparticles have a particle size of 20-50 nm and a spiropyran modification density of 0.5-1.0 μmol / m².

6. The preparation method according to claim 1, characterized in that... The hyperbranched fluorinated polyether has a molecular weight of 2000-3000 g / mol and a hydroxyl value of 155-175 mg KOH / g.

7. The preparation method according to any one of claims 1-6, characterized in that... The preparation of the nanoscale cerium-doped zinc oxide quantum dots includes the following steps: a) Add anhydrous ethanol to a three-necked round-bottom flask; b) Add zinc acetate dihydrate and cerium acetate hydrate, and stir to dissolve; c) Dissolve sodium hydroxide in anhydrous ethanol in another beaker; d) Under ice bath and nitrogen protection, slowly add sodium hydroxide solution dropwise to acetate solution while stirring; e) Continue stirring the reaction after heating; f) The centrifuged product was washed with anhydrous ethanol and deionized water; g) Dry the product in a vacuum oven.

8. The preparation method according to any one of claims 1-6, characterized in that... It also includes the following hot pressing steps: a) Cut the dried composite film; b) Place the film between polished stainless steel plates; c) Place the components into the hot press; d) Increase the temperature to 180±2℃; e) Apply a pressure of 20±1 MPa and maintain it for 45 minutes; f) Maintain pressure and cool slowly.

9. The preparation method according to claim 8, characterized in that... It also includes the following surface treatment steps: a) Place the thermoformed mask in a sealed chamber filled with nitrogen gas, with a nitrogen purity ≥ 99.99%; b) Use a UV lamp with a wavelength of 365±5 nm and a light intensity of 7.5±0.5 mW / cm²; c) Irradiate at 30±2℃ for 30 minutes to activate the photochromic groups on the surface.

10. The preparation method according to claim 9, characterized in that... It also includes the following post-processing steps: a) Prepare a 3 wt% hydrofluoric acid solution; b) Immerse the mask in a hydrofluoric acid solution; c) Rinse with deionized water; d) Wipe the surface with a lint-free cloth; e) Dry in a vacuum oven.

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