High-refraction wear-resistant glass microbead and preparation process thereof

Abstract

The application provides high-refraction wear-resistant glass microbeads and a preparation process thereof, and belongs to the technical field of glass microbeads; the preparation process comprises the following steps: surface modification of nano-titanium dioxide; addition of isocyanatoethyl methacrylate to prepare a precursor A; mixed heating reaction to prepare a precursor B; mixing of the precursor A, the precursor B and the surface modified titanium dioxide; addition of yttrium carbonate and zirconium tetrafluoride and mixed melting. The precursor A prepared by taking polycaprolactone tetrol as a raw material, the precursor B prepared by taking polypropylene glycol as a raw material and the surface modified titanium dioxide are mixed to prepare a mixed protective solution, the base glass microbeads are immersed in the mixed protective solution, a protective layer is coated on the surface of the base glass microbeads, the base glass microbeads are protected, the impact resistance and wear resistance of the base glass microbeads are improved, and the service life of the reflective road signs and road markings prepared by taking the glass microbeads as a raw material is prolonged.

Description

Technical Field

[0001] This invention relates to the field of rare earth permanent magnet materials technology, specifically to a high-refractive-index wear-resistant glass microsphere and its preparation process. Background Technology

[0002] Glass microspheres are tiny, spherical or near-spherical glass particles, usually made of borosilicate glass or other special glass formulations. They are generally divided into two main categories: solid glass microspheres and hollow glass microspheres. Solid glass microspheres are mainly used in traffic as reflective pavement markers and road markings. As an important reflective element in reflective materials, the strength of the reflective ability of glass microspheres directly affects the reflective performance of reflective materials. Not all solid microspheres have good retroreflective properties; only glass microspheres with a diameter of less than 0.8 mm and a refractive index of around 1.9 have retroreflective properties.

[0003] Currently, the refractive index of ordinary glass microspheres is around 1.5. To significantly increase the refractive index of finished glass microspheres, it is usually necessary to add elements with higher refractive indices, such as Pb and Bi, to the glass raw materials. However, these elements have disadvantages such as being harmful to the human body and not environmentally friendly. Therefore, existing technologies have emerged that improve the refractive index of glass microspheres by coating the surface of glass microspheres with high-refractive-index oxide films, such as titanium dioxide films or tin dioxide films. However, when coated glass microspheres are used as reflective road markers and road markings, the surface coating is easily peeled off due to friction from car tires, resulting in a decrease in the refractive index of the glass microspheres. In addition, although glass microspheres have a certain mechanical strength, long-term, high-intensity wheel rolling can still cause wear or local breakage of the surface microspheres. Especially when the marking coating itself is worn or aged, the microspheres lose effective protection and are more susceptible to damage.

[0004] Therefore, it is necessary to propose a high-refractive-index wear-resistant glass microsphere with strong impact resistance and its preparation process to improve the practicality of glass microspheres and extend their service life. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a high-refractive-index wear-resistant glass microsphere and its preparation process.

[0006] A high-refractive-index wear-resistant glass microsphere includes a matrix glass microsphere and a protective layer;

[0007] The matrix glass microspheres, by mass percentage, include: 15-25% sodium oxide, 5-10% calcium oxide, 8-10% aluminum oxide, 10-12% boron oxide, 0.2-0.4% yttrium carbonate and 0.1-0.2% zirconium tetrafluoride, with the balance being silicon dioxide.

[0008] A process for preparing high-refractive-index wear-resistant glass microspheres includes the following steps:

[0009] S1: Surface-modified nano-titanium dioxide

[0010] Nano-titanium dioxide was dispersed in an anhydrous ethanol solution of γ-aminopropyltriethoxysilane and heated for a first treatment. It was then dispersed in anhydrous pyridine and reacted with 2-bromoisobutyryl bromide. Finally, it was mixed with 2,2-bipyridine, cuprous bromide, n-propanol, 2-hydroxyethyl methacrylate and butanone to obtain surface-modified titanium dioxide.

[0011] S2: Preparation of precursor A by adding isoethyl methacrylate

[0012] Polycaprolactone tetraol, polycaprolactone triol and ethyl acetate were mixed and heated, then dicyclohexylmethane diisocyanate and butyl acetate were added to react, and then isocyanate methacrylate was added to continue the reaction to obtain precursor A.

[0013] S3: Preparation of precursor B by mixed heating reaction

[0014] Component A was prepared by heating and reacting polypropylene glycol with 4,4-diphenylmethane diisocyanate. Component B was then prepared by mixing polyether polyamine, 3,5-diethyltoluene diamine, and 4,4-bis-sec-butylaminodiphenylmethane. Finally, component A and component B were mixed and reacted to obtain precursor B.

[0015] S4: A mixture of precursor A, precursor B, and surface-modified titanium dioxide.

[0016] The above-mentioned precursor A, the above-mentioned precursor B and the above-mentioned surface-modified titanium dioxide are stirred and mixed, then the curing agent and diluent are added, and after stirring and mixing evenly, the mixture is homogenized for 10-20 minutes to obtain a mixed protective liquid.

[0017] S5: Add yttrium carbonate and zirconium tetrafluoride and mix and melt.

[0018] Silica, sodium oxide, calcium oxide, aluminum oxide, boron oxide, yttrium carbonate and zirconium tetrafluoride are mixed and melted, then water-quenched, ball-milled, and then placed in a bead-forming furnace to be spheroidized into beads. The beads are then immersed in the above-mentioned mixed protective liquid, taken out and heated to solidify, to obtain high-refractive-index wear-resistant glass microspheres.

[0019] Furthermore, S1 specifically includes the following steps:

[0020] S1.1: Dissolve γ-aminopropyltriethoxysilane in anhydrous ethanol to prepare a γ-aminopropyltriethoxysilane solution with a concentration of 1-3%;

[0021] S1.2: Disperse nano-titanium dioxide in the above γ-aminopropyltriethoxysilane solution, sonicate for 3-5 min, then heat to 40-50℃ and keep warm for 2-3 h, filter, wash with anhydrous ethanol and dry to obtain primary treated titanium dioxide;

[0022] S1.3: Disperse the above-treated titanium dioxide in anhydrous pyridine at a solid-liquid ratio of 1g:(10-20)mL, and then cool it in an ice-water bath at 1-3℃ to obtain a titanium dioxide dispersion.

[0023] S1.4: Add 6-8% by volume of 2-bromoisobutyryl bromide to the above titanium dioxide dispersion, react for 10-12 h, centrifuge, filter, wash with anhydrous ethanol and dry to obtain secondary treated titanium dioxide.

[0024] S1.5: Add the above-mentioned secondary treated titanium dioxide, 2,2-bipyridine, cuprous bromide, n-propanol, 2-hydroxyethyl methacrylate and butanone to the reactor at a solid-liquid ratio of (8-10)g:1g:1g:1mL:(40-50)mL:(40-50)mL. Under nitrogen protection, heat to 80-90℃ and react for 4-5 hours. Then, after centrifugation, washing with tetrahydrofuran, washing with anhydrous ethanol and vacuum drying, surface-modified titanium dioxide is obtained.

[0025] Furthermore, S2 specifically includes the following steps:

[0026] S2.1: Add polycaprolactone tetraol, polycaprolactone triol and ethyl acetate to the reaction chamber at a mass ratio of 1:(1.2-1.6):(3-5), heat to 70-80℃, and keep warm under reflux for 2-3 hours;

[0027] S2.2: Add dicyclohexylmethane diisocyanate to the reaction chamber at a uniform rate within 1-2 hours, continue to keep the temperature for 2-3 hours, and when it is naturally cooled to 40-50℃, add butyl acetate and continue to react for 40-50 minutes to obtain the prepolymer.

[0028] S2.3: Keeping the temperature constant, add isocyanate methacrylate to the above prepolymer and continue the reaction for 1-2 hours to modify it and obtain precursor A.

[0029] Furthermore, S3 specifically includes the following steps:

[0030] S3.1: Polypropylene glycol is vacuum dehydrated at 90-100℃ for 4-5 hours, then mixed with 4,4-diphenylmethane diisocyanate and heated to 70-80℃. Under nitrogen protection, the reaction is maintained at this temperature for 2-3 hours to obtain component A.

[0031] S3.2: Polyether polyamine, 3,5-diethyltoluene diamine and 4,4-bis-sec-butylaminodiphenylmethane are stirred and mixed, and then vacuum dehydrated for 2-3 hours to obtain component B;

[0032] S3.3: Mix the above components A and B by stirring and heating to 65-75℃, and react for 1-2 hours to obtain precursor B.

[0033] Furthermore, S5 specifically includes the following steps:

[0034] S5.1: Place silicon dioxide, sodium oxide, calcium oxide, aluminum oxide, boron oxide, yttrium carbonate and zirconium tetrafluoride in a mixer and mix them evenly. Heat the mixture to 1500-1600℃ at a rate of 40-50℃ / min to melt it, and keep it at that temperature for 3-4 hours to obtain a mixed melt.

[0035] S5.2: The above-mentioned mixed melt is water-quenched, then ball-milled in a ball mill, sieved, and then placed in a bead-forming furnace to be spheroidized into beads at a temperature of 1000-1200℃ to obtain matrix glass microspheres.

[0036] S5.3: Immerse the above-mentioned matrix glass microspheres in the mixed protective liquid prepared in step S4, take them out, and then cure them in an oven at 80-90℃ to form a protective layer, thereby obtaining high refractive wear-resistant glass microspheres.

[0037] Furthermore, the mass ratio of dicyclohexylmethane diisocyanate to ethyl acetate is 1:(3-4), and the mass ratio of butyl acetate to ethyl acetate is (7.5-8.5):1.

[0038] Furthermore, the molar ratio of isocyanate methacrylate to the prepolymer is (3.5-4.5):1.

[0039] Furthermore, by weight percentage, the mixed protective liquid comprises: 30-40% precursor A, 20-30% precursor B, 10-20% modified titanium dioxide, 2-3% curing agent, and the balance being diluent.

[0040] Further, by weight, precursor B comprises: 40-50 parts of polypropylene glycol, 50-60 parts of 4,4-diphenylmethane diisocyanate, 70-80 parts of polyether polyamine, 10-20 parts of 3,5-diethyltoluene diamine and 5-10 parts of 4,4-bis-sec-butylaminodiphenylmethane.

[0041] Compared with the prior art, the beneficial effects of the present invention are:

[0042] 1. The high-refractive-index wear-resistant glass microspheres of this invention consist of a matrix glass microsphere and a protective layer. A mixed protective liquid is prepared by mixing precursor A (made from polycaprolactone tetraol, polycaprolactone triol, and ethyl acetate), precursor B (made from polypropylene glycol, 4,4-diphenylmethane diisocyanate, and polyether polyamine), and surface-modified titanium dioxide. The matrix glass microspheres are then immersed in this mixed protective liquid, resulting in a protective layer coating the surface of the matrix glass microspheres. This protects the matrix glass microspheres, improves their wear resistance, and prevents long-term, high-intensity wheel rolling that could cause wear or localized breakage of the glass microspheres, thereby extending the service life of reflective road markers and road markings made from glass microspheres.

[0043] 2. This invention first treats titanium dioxide with γ-aminopropyltriethoxysilane, then disperses it in anhydrous pyridine and reacts it with 2-bromoisobutyryl bromide for a second treatment. Then, it is mixed with 2,2-bipyridine, cuprous bromide, n-propanol, 2-hydroxyethyl methacrylate, and butanone for surface modification. This not only reduces the aggregation and hydrogen bonding between nano-titanium dioxide particles, improving their dispersibility in the mixed system of precursor A and precursor B, but also enhances the tensile strength, elongation at break, and shear strength of the protective layer formed on the surface of the matrix glass microspheres by the mixed protective liquid. This strengthens and toughens the protective layer and also improves its adhesion to the matrix glass microspheres.

[0044] 3. This invention first mixes polycaprolactone tetraol, polycaprolactone triol, and ethyl acetate and refluxes them at a certain temperature. Then, dicyclohexylmethane diisocyanate and butyl acetate are added to react and obtain a prepolymer with a "cage-like" structure. Through its polyhydroxy structure, it can increase the crosslinking density of the formed protective layer and form a spatial network structure, thereby improving the wear resistance of the protective layer. Then, the prepolymer is modified with ethyl isocyanate of methacrylate. Due to the introduction of acrylic acid segments, the orientation force between the protective layer formed by the mixed protective liquid and the matrix glass microspheres is increased, improving the matching between the protective layer and the matrix glass microspheres, and thus improving the adhesion of the protective layer.

[0045] 4. This invention produces matrix glass microspheres with a particle size of less than 800 μm and a refractive index greater than or equal to 1.9, using silicon dioxide, sodium oxide, calcium oxide, aluminum oxide, boron oxide, yttrium carbonate, and zirconium tetrafluoride as raw materials. These microspheres possess the characteristics of high-refractive-index glass microspheres. The introduction of yttrium through yttrium carbonate, due to its abundant energy level structure and large electron affinity, effectively alters the local electric field distribution and increases electron density within the glass network, thereby improving the refractive index of the prepared matrix glass microspheres. Furthermore, the addition of zirconium tetrafluoride synergizes with the effect of yttrium, further enhancing the refractive index of the matrix glass microspheres. Detailed Implementation

[0046] The following describes in detail a high-refractive-index wear-resistant glass microsphere and its preparation process provided by the present invention, with reference to embodiments and specific examples. It should be noted that, to make the embodiments more detailed, the following embodiments are the best and preferred embodiments; those skilled in the art can also use other alternative methods to implement some known technologies; moreover, the embodiments are only for more specific descriptions and are not intended to specifically limit the present invention.

[0047] Example 1

[0048] A process for preparing high-refractive-index wear-resistant glass microspheres includes the following steps:

[0049] S1: Surface-modified nano-titanium dioxide

[0050] γ-aminopropyltriethoxysilane was dissolved in anhydrous ethanol to prepare a 1% γ-aminopropyltriethoxysilane solution. Nano-titanium dioxide was then dispersed in the γ-aminopropyltriethoxysilane solution and sonicated for 3 min. The solution was then heated to 40°C and held at that temperature for 2 h. After filtration, washing with anhydrous ethanol, and drying, primary-treated titanium dioxide was obtained. This primary-treated titanium dioxide was then dispersed in anhydrous pyridine at a solid-liquid ratio of 1 g:10 mL and cooled in an ice-water bath at 1°C to obtain a titanium dioxide dispersion. Subsequently, the titanium dioxide... 6% by volume of 2-bromoisobutyryl bromide was added to the dispersion, and the reaction was carried out for 10 h. After centrifugation, filtration, washing with anhydrous ethanol, and drying, secondary treated titanium dioxide was obtained. Finally, the secondary treated titanium dioxide, 2,2-bipyridine, cuprous bromide, n-propanol, 2-hydroxyethyl methacrylate, and butanone were added to the reactor at a solid-liquid ratio of 8 g: 1 g: 1 g: 1 mL: 40 mL: 40 mL. Under nitrogen protection, the mixture was heated to 80 °C and reacted for 4 h. After centrifugation, washing with tetrahydrofuran, washing with anhydrous ethanol, and vacuum drying, surface-modified titanium dioxide was obtained.

[0051] S2: Preparation of precursor A by adding isoethyl methacrylate

[0052] Polycaprolactone tetraol, polycaprolactone triol, and ethyl acetate were added to a reaction chamber at a mass ratio of 1:1.2:3. The mixture was heated to 70°C and refluxed for 2 hours. Then, dicyclohexylmethane diisocyanate was added to the reaction chamber at a uniform rate over 1 hour. The reaction was continued for another 2 hours. After naturally cooling to 40°C, butyl acetate was added, and the reaction was continued for 40 minutes to obtain a prepolymer. The mass ratio of dicyclohexylmethane diisocyanate to ethyl acetate was 1:3, and the mass ratio of butyl acetate to ethyl acetate was 7.5:1. The temperature was kept constant, and isocyanate methacrylate was added to the prepolymer. The reaction was continued for 1 hour to modify the prepolymer and obtain precursor A. The molar ratio of isocyanate methacrylate to the prepolymer was 3.5:1.

[0053] S3: Preparation of precursor B by mixed heating reaction

[0054] By weight, 40 parts of polypropylene glycol were vacuum dehydrated at 90°C for 4 hours, then mixed with 50 parts of 4,4-diphenylmethane diisocyanate and heated to 70°C. Under nitrogen protection, the mixture was kept at this temperature for 2 hours to obtain component A, which was set aside. Then, 70 parts of polyether polyamine, 10 parts of 3,5-diethyltoluene diamine and 5 parts of 4,4-bis-sec-butylaminodiphenylmethane were stirred and mixed, and vacuum dehydrated for 2 hours to obtain component B, which was set aside. Subsequently, component A and component B were stirred and mixed and heated to 65°C for 1 hour to obtain precursor B.

[0055] S4: A mixture of precursor A, precursor B, and surface-modified titanium dioxide.

[0056] By weight percentage, 30% of the above precursor A, 20% of the above precursor B and 10% of the above surface-modified titanium dioxide are stirred and mixed, then 2% of curing agent and 38% of diluent are added, stirred and mixed evenly, and then homogenized for 10 minutes to obtain a mixed protective liquid.

[0057] S5: Add yttrium carbonate and zirconium tetrafluoride and mix and melt.

[0058] By mass percentage, 61.7% silica, 15% sodium oxide, 5% calcium oxide, 8% aluminum oxide, 10% boron oxide, 0.2% yttrium carbonate, and 0.1% zirconium tetrafluoride are mixed evenly in a mixer, heated to 1500℃ at a rate of 40℃ / min for melting, and held at that temperature for 3 hours to obtain a mixed melt. The mixed melt is then water-quenched, ball-milled, sieved, and then placed in a bead-forming furnace at 1000℃ to form beads, obtaining matrix glass microspheres. Finally, the matrix glass microspheres are immersed in the above mixed protective liquid, removed, and then cured in an oven at 80℃ to form a protective layer, resulting in high-refractive-index wear-resistant glass microspheres.

[0059] The performance test results are shown in Table 1 below:

[0060] 1. Use an abrasion tester to test the abrasion resistance of the protective layer. Set the rotation speed of the stage of the abrasion tester to 60 r / min and perform abrasion tests on the prepared high-refractive-index abrasion-resistant glass microspheres until the protective layer is worn away, exposing the matrix glass microspheres, and record the time taken for this process;

[0061] 2. In accordance with GB / T7124—2008 standard, the tensile strength, elongation at break and shear strength of the protective layer were tested using an electronic universal testing machine;

[0062] 3. The particle size of the high-refractive-index wear-resistant glass microspheres was measured using a laser particle size analyzer, and their refractive index was measured by the oil immersion method.

[0063] Example 2

[0064] A process for preparing high-refractive-index wear-resistant glass microspheres includes the following steps:

[0065] S1: Surface-modified nano-titanium dioxide

[0066] γ-aminopropyltriethoxysilane was dissolved in anhydrous ethanol to prepare a 2% γ-aminopropyltriethoxysilane solution. Nano-titanium dioxide was then dispersed in the γ-aminopropyltriethoxysilane solution and sonicated for 4 min. The solution was then heated to 45°C and held at that temperature for 2.5 h. After filtration, washing with anhydrous ethanol, and drying, primary-treated titanium dioxide was obtained. This primary-treated titanium dioxide was then dispersed in anhydrous pyridine at a solid-liquid ratio of 1 g:15 mL and cooled in an ice-water bath at 2°C to obtain a titanium dioxide dispersion. Subsequently, the titanium dioxide... 7% by volume of 2-bromoisobutyryl bromide was added to the dispersion, and the reaction was carried out for 11 h. After centrifugation, filtration, washing with anhydrous ethanol, and drying, secondary treated titanium dioxide was obtained. Finally, the secondary treated titanium dioxide, 2,2-bipyridine, cuprous bromide, n-propanol, 2-hydroxyethyl methacrylate, and butanone were added to the reactor at a solid-liquid ratio of 9 g: 1 g: 1 g: 1 mL: 45 mL: 45 mL. Under nitrogen protection, the mixture was heated to 85 °C and reacted for 4.5 h. After centrifugation, washing with tetrahydrofuran, washing with anhydrous ethanol, and vacuum drying, surface-modified titanium dioxide was obtained.

[0067] S2: Preparation of precursor A by adding isoethyl methacrylate

[0068] Polycaprolactone tetraol, polycaprolactone triol, and ethyl acetate were added to a reaction chamber at a mass ratio of 1:1.4:4. The mixture was heated to 75°C and refluxed for 2.5 hours. Then, dicyclohexylmethane diisocyanate was added to the reaction chamber at a uniform rate over 1.5 hours. The reaction was continued for another 2.5 hours. After naturally cooling to 45°C, butyl acetate was added, and the reaction was continued for 45 minutes to obtain a prepolymer. The mass ratio of dicyclohexylmethane diisocyanate to ethyl acetate was 1:3.5, and the mass ratio of butyl acetate to ethyl acetate was 8:1. The temperature was kept constant, and isocyanate methacrylate was added to the prepolymer. The reaction was continued for another 1.5 hours to modify the prepolymer and obtain precursor A. The molar ratio of isocyanate methacrylate to the prepolymer was 4:1.

[0069] S3: Preparation of precursor B by mixed heating reaction

[0070] By weight, 45 parts of polypropylene glycol were vacuum dehydrated at 95°C for 4.5 h, then mixed with 55 parts of 4,4-diphenylmethane diisocyanate and heated to 75°C. Under nitrogen protection, the mixture was kept at this temperature for 2.5 h to obtain component A, which was set aside. Then, 75 parts of polyether polyamine, 15 parts of 3,5-diethyltoluene diamine and 7 parts of 4,4-bis-sec-butylaminodiphenylmethane were stirred and mixed, and vacuum dehydrated for 2.5 h to obtain component B, which was set aside. Subsequently, component A and component B were stirred and mixed and heated to 70°C for 1.5 h to obtain precursor B.

[0071] S4: A mixture of precursor A, precursor B, and surface-modified titanium dioxide.

[0072] By weight percentage, 35% of the above precursor A, 25% of the above precursor B and 15% of the above surface-modified titanium dioxide are stirred and mixed, then 2.5% of curing agent and 22.5% of diluent are added, stirred and mixed evenly, and then homogenized for 15 minutes to obtain a mixed protective liquid.

[0073] S5: Add yttrium carbonate and zirconium tetrafluoride and mix and melt.

[0074] By mass percentage, 52.55% silica, 20% sodium oxide, 7% calcium oxide, 9% aluminum oxide, 11% boron oxide, 0.3% yttrium carbonate, and 0.15% zirconium tetrafluoride are mixed evenly in a mixer, heated to 1550°C at a rate of 45°C / min for melting, and held at that temperature for 3.5 hours to obtain a mixed melt. The mixed melt is then water-quenched, ball-milled, sieved, and then placed in a bead-forming furnace at 1100°C to form beads, obtaining matrix glass microspheres. Finally, the matrix glass microspheres are immersed in the above mixed protective liquid, removed, and then cured in an oven at 85°C to form a protective layer, resulting in high-refractive-index wear-resistant glass microspheres.

[0075] The performance test results are shown in Table 1 below:

[0076] 1. Use an abrasion tester to test the abrasion resistance of the protective layer. Set the rotation speed of the stage of the abrasion tester to 60 r / min and perform abrasion tests on the prepared high-refractive-index abrasion-resistant glass microspheres until the protective layer is worn away, exposing the matrix glass microspheres, and record the time taken for this process;

[0077] 2. In accordance with GB / T7124—2008 standard, the tensile strength, elongation at break and shear strength of the protective layer were tested using an electronic universal testing machine;

[0078] 3. The particle size of the high-refractive-index wear-resistant glass microspheres was measured using a laser particle size analyzer, and their refractive index was measured by the oil immersion method.

[0079] Example 3

[0080] A process for preparing high-refractive-index wear-resistant glass microspheres includes the following steps:

[0081] S1: Surface-modified nano-titanium dioxide

[0082] γ-aminopropyltriethoxysilane was dissolved in anhydrous ethanol to prepare a 3% γ-aminopropyltriethoxysilane solution. Nano-titanium dioxide was then dispersed in the γ-aminopropyltriethoxysilane solution and sonicated for 5 min. The solution was then heated to 50°C and held at that temperature for 3 h. After filtration, washing with anhydrous ethanol, and drying, primary-treated titanium dioxide was obtained. This primary-treated titanium dioxide was then dispersed in anhydrous pyridine at a solid-liquid ratio of 1 g: 20 mL and cooled in an ice-water bath at 3°C ​​to obtain a titanium dioxide dispersion. Subsequently, the titanium dioxide... 8% by volume of 2-bromoisobutyryl bromide was added to the dispersion, and the reaction was carried out for 12 h. After centrifugation, filtration, washing with anhydrous ethanol, and drying, secondary treated titanium dioxide was obtained. Finally, the secondary treated titanium dioxide, 2,2-bipyridine, cuprous bromide, n-propanol, 2-hydroxyethyl methacrylate, and butanone were added to the reactor at a solid-liquid ratio of 10 g: 1 g: 1 g: 1 mL: 50 mL: 50 mL. Under nitrogen protection, the mixture was heated to 90 °C and reacted for 5 h. After centrifugation, washing with tetrahydrofuran, washing with anhydrous ethanol, and vacuum drying, surface-modified titanium dioxide was obtained.

[0083] S2: Preparation of precursor A by adding isoethyl methacrylate

[0084] Polycaprolactone tetraol, polycaprolactone triol, and ethyl acetate were added to a reaction chamber at a mass ratio of 1:1.6:5. The mixture was heated to 80°C and refluxed for 3 hours. Then, dicyclohexylmethane diisocyanate was added to the reaction chamber at a uniform rate over 2 hours. The reaction was continued for another 3 hours. After naturally cooling to 50°C, butyl acetate was added, and the reaction was continued for 50 minutes to obtain a prepolymer. The mass ratio of dicyclohexylmethane diisocyanate to ethyl acetate was 1:4, and the mass ratio of butyl acetate to ethyl acetate was 8.5:1. The temperature was kept constant, and isocyanate methacrylate was added to the prepolymer. The reaction was continued for 2 hours to modify the prepolymer and obtain precursor A. The molar ratio of isocyanate methacrylate to the prepolymer was 4.5:1.

[0085] S3: Preparation of precursor B by mixed heating reaction

[0086] By weight, 50 parts of polypropylene glycol were vacuum dehydrated at 100°C for 5 hours, then mixed with 60 parts of 4,4-diphenylmethane diisocyanate and heated to 80°C. Under nitrogen protection, the mixture was kept at this temperature for 3 hours to obtain component A, which was set aside. Then, 80 parts of polyether polyamine, 20 parts of 3,5-diethyltoluene diamine and 10 parts of 4,4-bis-sec-butylaminodiphenylmethane were stirred and mixed, and vacuum dehydrated for 3 hours to obtain component B, which was set aside. Subsequently, component A and component B were stirred and mixed and heated to 75°C for 2 hours to obtain precursor B.

[0087] S4: A mixture of precursor A, precursor B, and surface-modified titanium dioxide.

[0088] By weight percentage, 40% of the above precursor A, 30% of the above precursor B and 20% of the above surface-modified titanium dioxide are stirred and mixed, then 3% of curing agent and 7% of diluent are added, stirred and mixed evenly, and then homogenized for 20 minutes to obtain a mixed protective liquid.

[0089] S5: Add yttrium carbonate and zirconium tetrafluoride and mix and melt.

[0090] By mass percentage, 42.4% silica, 25% sodium oxide, 10% calcium oxide, 10% aluminum oxide, 12% boron oxide, 0.4% yttrium carbonate, and 0.2% zirconium tetrafluoride are mixed evenly in a mixer, heated to 1600℃ at a rate of 50℃ / min for melting, and held at that temperature for 4 hours to obtain a mixed melt. The mixed melt is then water-quenched, ball-milled, sieved, and then placed in a bead-forming furnace at 1200℃ to form beads, obtaining matrix glass microspheres. Finally, the matrix glass microspheres are immersed in the above mixed protective liquid, removed, and then cured in an oven at 90℃ to form a protective layer, resulting in high-refractive-index wear-resistant glass microspheres.

[0091] The performance test results are shown in Table 1 below:

[0092] 1. Use an abrasion tester to test the abrasion resistance of the protective layer. Set the rotation speed of the stage of the abrasion tester to 60 r / min and perform abrasion tests on the prepared high-refractive-index abrasion-resistant glass microspheres until the protective layer is worn away, exposing the matrix glass microspheres, and record the time taken for this process;

[0093] 2. In accordance with GB / T7124—2008 standard, the tensile strength, elongation at break and shear strength of the protective layer were tested using an electronic universal testing machine;

[0094] 3. The particle size of the high-refractive-index wear-resistant glass microspheres was measured using a laser particle size analyzer, and their refractive index was measured by the oil immersion method.

[0095] Table 1: Summary of Performance Test Results for Examples 1-3

[0096]

[0097] As shown in Table 1, the performance test results indicate that the time taken for the protective layer to wear down until the base glass microspheres were exposed was greater than 800 hours. This demonstrates that by preparing a mixed protective solution using precursor A (made from polycaprolactone tetraol, polycaprolactone triol, and ethyl acetate), precursor B (made from polypropylene glycol, 4,4-diphenylmethane diisocyanate, and polyether polyamine), and surface-modified titanium dioxide, and then immersing the base glass microspheres in this solution, a protective layer is formed on the surface of the base glass microspheres. This protects the base glass microspheres, improves their wear resistance, and prevents long-term, high-intensity wheel rolling from causing wear or local breakage of the glass microspheres, thereby extending the service life of reflective road markers and road markings made from glass microspheres.

[0098] Comparative Example 1

[0099] The difference between this comparative example and Example 1 is that step S1 is removed, and the surface-modified titanium dioxide in step S4 is replaced with an equal amount of nano-titanium dioxide. Then, the performance test is carried out according to the performance test method in Example 1, and the results are shown in Table 2 below.

[0100] Table 2: Comparison of performance test results between Comparative Example 1 and Example 1

[0101]

[0102]

[0103] The performance test comparison between Comparative Example 1 and Example 1 shows that the tensile strength, elongation at break, and shear strength of Comparative Example 1 are 20 MPa, 8%, and 17 MPa, respectively, all lower than those of Example 1. This indicates that by first treating titanium dioxide with γ-aminopropyltriethoxysilane, then dispersing it in anhydrous pyridine and reacting it with 2-bromoisobutyryl bromide for a second treatment, and then reacting it with 2,2-bipyridine, cuprous bromide, n-propanol, 2-hydroxyethyl methacrylate, and butanone for surface modification, the aggregation and hydrogen bonding between nano-titanium dioxide particles can be improved. The reduced effect improves the dispersibility of nano-titanium dioxide in the mixed system of precursor A and precursor B, and can also improve the tensile strength, elongation at break and shear strength of the protective layer formed by the mixed protective liquid on the surface of the matrix glass microspheres, thus enhancing and toughening the protective layer. Moreover, since shear strength refers to the maximum stress that a material can withstand when it undergoes relative slippage and eventually fails under shear force, it can reflect the adhesion between the coating and the substrate, as well as the stability of the internal structure of the coating. Therefore, modifying the surface of nano-titanium dioxide also improves the adhesion of the protective layer to the matrix glass microspheres.

[0104] Comparative Example 2

[0105] The difference between this comparative example and Example 1 is that step S2 is removed and precursor A in step S4 is removed. Then, the performance test is performed according to the performance test method in Example 1, and the results are shown in Table 3 below.

[0106] Table 3: Comparison of performance test results between Comparative Example 2 and Example 1

[0107]

[0108] The performance test comparison between Comparative Example 2 and Example 1 shows that the wear time and shear strength of the protective layer in Comparative Example 2 are 427 MPa and 22 MPa, respectively, both less than those in Example 1. This indicates that by first mixing polycaprolactone tetraol, polycaprolactone triol, and ethyl acetate and refluxing them at a low temperature, and then adding dicyclohexylmethane diisocyanate and butyl acetate to react, a prepolymer with a "cage-like" structure is obtained. Through its polyhydroxy structure, the prepolymer can increase the crosslinking density of the formed protective layer and form a spatial network structure, thereby improving the wear resistance of the protective layer. Then, the prepolymer is modified with isocyanate methacrylate. Due to the introduction of acrylic acid segments, the orientation force between the protective layer formed by the mixed protective liquid and the matrix glass microspheres is increased, improving the matching between the protective layer and the matrix glass microspheres, and thus improving the adhesion of the protective layer.

[0109] Comparative Example 3

[0110] The difference between this comparative example and Example 1 is that the yttrium carbonate in step S5 is replaced with an equal amount of zirconium tetrafluoride, and then the performance test is carried out according to the performance test method in Example 1. The results are shown in Table 4 below.

[0111] Comparative Example 4

[0112] The difference between this comparative example and Example 1 is that zirconium tetrafluoride in step S5 is replaced with an equal amount of yttrium carbonate, and then the performance test is carried out in accordance with the performance test method in Example 1. The results are shown in Table 4 below.

[0113] Comparative Example 5

[0114] The difference between this comparative example and Example 1 is that yttrium carbonate and zirconium tetrafluoride were removed in step S5, and then the performance was tested according to the performance test method in Example 1. The results are shown in Table 4 below.

[0115] Table 4: Comparison of performance test results between Comparative Examples 3-5 and Example 1

[0116]

[0117] As can be seen from Table 4 above, the refractive indices of the matrix glass microspheres with added zirconium tetrafluoride and yttrium carbonate are 1.87 and 1.84, respectively, both lower than those of the matrix glass microspheres with added zirconium tetrafluoride and yttrium carbonate in Example 1. Furthermore, the refractive index of the matrix glass microspheres in Comparative Example 5 without added zirconium tetrafluoride and yttrium carbonate is lower than that of the matrix glass microspheres with added zirconium tetrafluoride and yttrium carbonate. Therefore, by using silicon dioxide, sodium oxide, calcium oxide, aluminum oxide, boron oxide, yttrium carbonate, and zirconium tetrafluoride as... The matrix glass microspheres prepared from the raw materials have a particle size of less than 800 μm and a refractive index greater than or equal to 1.9, possessing the characteristics of high refractive index glass microspheres. Among them, yttrium is introduced by yttrium carbonate. Due to the rich energy level structure and large electron affinity of yttrium, it can effectively change the local electric field distribution in the glass network and increase the electron density, thereby improving the refractive index of the prepared matrix glass microspheres. The addition of zirconium tetrafluoride can synergize with the effect of yttrium to further improve the refractive index of the matrix glass microspheres.

[0118] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A type of high-refractive-index wear-resistant glass microsphere, characterized in that, Includes a matrix of glass microspheres and a protective layer; The matrix glass microspheres, by mass percentage, include: 15-25% sodium oxide, 5-10% calcium oxide, 8-10% aluminum oxide, 10-12% boron oxide, 0.2-0.4% yttrium carbonate and 0.1-0.2% zirconium tetrafluoride, with the balance being silicon dioxide; The preparation process of the high-refractive-index wear-resistant glass microspheres includes the following steps: S1: Surface-modified nano-titanium dioxide S1.1: Dissolve γ-aminopropyltriethoxysilane in anhydrous ethanol to prepare a γ-aminopropyltriethoxysilane solution with a concentration of 1-3%; S1.2: Disperse nano-titanium dioxide in the above γ-aminopropyltriethoxysilane solution, sonicate for 3-5 min, then heat to 40-50℃ and keep warm for 2-3 h, filter, wash with anhydrous ethanol and dry to obtain primary treated titanium dioxide; S1.3: Disperse the above-treated titanium dioxide in anhydrous pyridine at a solid-liquid ratio of 1g:(10-20)mL, and then cool it in an ice-water bath at 1-3℃ to obtain a titanium dioxide dispersion. S1.4: Add 6-8% by volume of 2-bromoisobutyryl bromide to the above titanium dioxide dispersion, react for 10-12 h, centrifuge, filter, wash with anhydrous ethanol and dry to obtain secondary treated titanium dioxide; S1.5: Add the above-mentioned secondary treated titanium dioxide, 2,2-bipyridine, cuprous bromide, n-propanol, 2-hydroxyethyl methacrylate and butanone to the reactor at a solid-liquid ratio of (8-10) g: 1 g: 1 g: 1 mL: (40-50) mL: (40-50) mL. Under nitrogen protection, heat to 80-90℃ and react for 4-5 h. Then, after centrifugation, washing with tetrahydrofuran, washing with anhydrous ethanol and vacuum drying, surface-modified titanium dioxide is obtained. S2: Preparation of precursor A by adding isoethyl methacrylate S2.1: Add polycaprolactone tetraol, polycaprolactone triol and ethyl acetate to the reaction chamber at a mass ratio of 1:(1.2-1.6):(3-5), heat to 70-80℃, and keep warm under reflux for 2-3 hours; S2.2: Add dicyclohexylmethane diisocyanate to the reaction chamber at a uniform rate within 1-2 hours, continue to keep the temperature for 2-3 hours, and when it is naturally cooled to 40-50℃, add butyl acetate and continue to react for 40-50 minutes to obtain the prepolymer. S2.3: Keeping the temperature constant, add isocyanate methacrylate to the above prepolymer and continue the reaction for 1-2 hours to modify it and obtain precursor A; S3: Preparation of precursor B by mixed heating reaction S3.1: Polypropylene glycol is vacuum dehydrated at 90-100℃ for 4-5 hours, then mixed with 4,4-diphenylmethane diisocyanate and heated to 70-80℃. Under nitrogen protection, the reaction is maintained at this temperature for 2-3 hours to obtain component A. S3.2: Polyether polyamine, 3,5-diethyltoluenediamine and 4,4-bis-sec-butylaminodiphenylmethane are stirred and mixed, and then vacuum dehydrated for 2-3 hours to obtain component B; S3.3: Mix the above components A and B by stirring and heating to 65-75℃, and react for 1-2 hours to obtain precursor B; S4: A mixture of precursor A, precursor B, and surface-modified titanium dioxide. The above-mentioned precursor A, the above-mentioned precursor B and the above-mentioned surface-modified titanium dioxide are stirred and mixed, then the curing agent and diluent are added, and after stirring and mixing evenly, the mixture is homogenized for 10-20 minutes to obtain a mixed protective liquid. S5: Add yttrium carbonate and zirconium tetrafluoride and mix and melt. Silica, sodium oxide, calcium oxide, aluminum oxide, boron oxide, yttrium carbonate and zirconium tetrafluoride are mixed and melted, then water-quenched, ball-milled, and then placed in a bead-forming furnace to be spheroidized into beads. The beads are then immersed in the above-mentioned mixed protective liquid, taken out and heated to solidify, to obtain high-refractive-index wear-resistant glass microspheres.

2. The high-refractive-index wear-resistant glass microspheres according to claim 1, characterized in that, S5 specifically includes the following steps: S5.1: Place silicon dioxide, sodium oxide, calcium oxide, aluminum oxide, boron oxide, yttrium carbonate and zirconium tetrafluoride in a mixer and mix them evenly. Heat the mixture to 1500-1600℃ at a rate of 40-50℃ / min to melt it, and keep it at that temperature for 3-4 hours to obtain a mixed melt. S5.2: The above-mentioned mixed melt is water-quenched, then ball-milled in a ball mill, sieved, and then placed in a bead-forming furnace to be spheroidized into beads at a temperature of 1000-1200℃ to obtain matrix glass microspheres. S5.3: Immerse the above-mentioned matrix glass microspheres in the mixed protective liquid prepared in step S4, take them out, and then cure them in an oven at 80-90℃ to form a protective layer, thereby obtaining high refractive wear-resistant glass microspheres.

3. The high-refractive-index wear-resistant glass microspheres according to claim 1, characterized in that, The mass ratio of dicyclohexylmethane diisocyanate to ethyl acetate is 1:(3-4), and the mass ratio of butyl acetate to ethyl acetate is (7.5-8.5):

1.

4. The high-refractive-index wear-resistant glass microspheres according to claim 1, characterized in that, The molar ratio of isocyanate methacrylate to prepolymer is (3.5-4.5):

1.

5. The high-refractive-index wear-resistant glass microspheres according to claim 1, characterized in that, By weight percentage, the mixed protective liquid comprises: 30-40% precursor A, 20-30% precursor B, 10-20% modified titanium dioxide, 2-3% curing agent, and the balance being diluent.

6. The high-refractive-index wear-resistant glass microspheres according to claim 1, characterized in that, By weight, precursor B comprises: 40-50 parts polypropylene glycol, 50-60 parts 4,4-diphenylmethane diisocyanate, 70-80 parts polyether polyamine, 10-20 parts 3,5-diethyltoluene diamine and 5-10 parts 4,4-bis-sec-butylaminodiphenylmethane.

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