High-transparency anti-cracking microcrystalline glass and preparation method thereof

Abstract

This invention discloses a high-transparency, crack-resistant microcrystalline glass and its preparation method, belonging to the field of microcrystalline glass technology. The microcrystalline glass comprises a microcrystalline glass substrate and a crack-resistant coating. The crack-resistant coating is composed of polyurethane prepolymer, nano-silica, modified organosilicon monomer, small molecule polyol, dibutyltin dilaurate, and a silane coupling agent in specific mass proportions. This invention first synthesizes a modified organosilicon monomer containing a rigid benzoxazole structure and hindered phenolic antioxidant groups through a multi-step reaction, and then prepares the polyurethane prepolymer; next, the components are mixed to form a coating liquid; finally, the microcrystalline glass substrate is surface-activated, coated, and cured. Through the synergistic effect of the components, this invention enables the microcrystalline glass to maintain high transparency while also possessing excellent crack resistance, wear resistance, weather resistance, and hydrophobicity, effectively solving the technical problems of easy cracking, yellowing, and contamination in existing microcrystalline glass.

Description

Technical Field

[0001] This invention belongs to the field of microcrystalline glass technology, and particularly relates to a high-transparency, crack-resistant microcrystalline glass and its preparation method. Background Technology

[0002] Glass-ceramics (glass-ceramics) are polycrystalline solid materials prepared from glass particles through sintering and crystallization processes. They cleverly combine the dual core characteristics of glass and ceramics, with a surface texture close to that of ceramics and superior brightness. They are significantly tougher than ordinary glass, and also possess outstanding weather resistance, wear resistance, and stain resistance. Their water absorption rate is almost zero, and they are resistant to acid and alkali corrosion. They can maintain color stability for a long time, so they are widely used in many fields such as architectural decoration, electronic device packaging, high-end kitchenware, and optical components.

[0003] Despite the numerous advantages of existing microcrystalline glass, there are still some technical shortcomings that need to be addressed in practical applications. On the one hand, the crack resistance of traditional microcrystalline glass is insufficient to meet the requirements of complex working conditions. Under external impact, sudden temperature changes, or long-term stress, microcracks are easily generated on the surface, and these cracks can propagate rapidly, seriously affecting the structural integrity and service life of the material. On the other hand, some microcrystalline glass products experience problems such as decreased light transmittance and yellowing after long-term use, especially those products made from aromatic raw materials, where the yellowing phenomenon is more pronounced. At the same time, their surfaces lack effective protective mechanisms, resulting in an imbalance between rigidity and toughness, making them prone to cracking due to brittleness. Furthermore, they are easily contaminated by dust, water stains, and other pollutants, further limiting their application in high-end fields where there are stringent requirements for transparency, crack resistance, and long-term stability.

[0004] Different approaches exist in existing technologies to improve the performance of glass-ceramics. For example, patent CN201510875782.8 discloses an amber-colored glass-ceramic and its preparation method. This method involves a specific composition of oxides such as SiO2, Al2O3, TiO2, CuO, and MgO / ZnO, followed by melting, molding, and heat treatment processes to precipitate microcrystals within the glass matrix, resulting in a glass-ceramic with high Mohs hardness and high-temperature resistance. This technical solution primarily focuses on improving the material's hardness, heat resistance, and chemical stability to overcome the defects of ordinary amber-colored glass, such as easy scratching and poor high-temperature resistance, making it suitable for decorative building materials and other fields. However, this method of modification through adjusting the basic components and crystallization process mainly focuses on improving the overall mechanical strength and thermal stability of the material, resulting in a relatively singular performance improvement direction. The glass-ceramic is a specific amber color, and its light transmittance is limited by the color itself. More importantly, it does not offer effective solutions to the comprehensive problems of microcrack formation on the surface of the glass-ceramic, insufficient impact resistance, and the need to maintain transparency and prevent surface staining during long-term use. Especially for high-end applications requiring high transparency, excellent crack resistance, and long-lasting surface protection, the limitations of this type of overall modification technology remain obvious. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention coats microcrystalline glass with a coating liquid containing polyurethane prepolymer, nano-silica, modified organosilicon monomers and other components, so that microcrystalline glass has the advantages of high transparency, excellent crack resistance, good wear resistance, long-term stability and hydrophobicity and antifouling.

[0006] To achieve the above objectives, the following technical solution is adopted: On the one hand, the present invention provides a high-transparency crack-resistant microcrystalline glass, including a microcrystalline glass substrate and a crack-resistant coating; the crack-resistant coating includes the following components in parts by weight: 50-80 parts of polyurethane prepolymer, 5-15 parts of nano-silica, 10-30 parts of modified organosilicon monomer, 2-5 parts of small molecule polyol, 0.1-1 parts of dibutyltin dilaurate, and 1-3 parts of silane coupling agent.

[0007] Furthermore, the modified organosilicon monomer is prepared through the following steps: S1. 5-Amino-2-(2-chloro-4-aminophenyl)benzoxazole and 3,5-di-tert-butyl-4-hydroxybenzaldehyde were added to anhydrous ethanol, and glacial acetic acid was added dropwise as a catalyst. The mixture was stirred at 40-60℃ for 4-6 hours. After the reaction was completed, the mixture was cooled to room temperature, and a solid was precipitated. The solid was filtered, washed three times with anhydrous ethanol, and dried under vacuum to obtain intermediate A. S2. Add intermediate A and glutamic acid to N,N-dimethylformamide, add anhydrous potassium carbonate, stir and react at 70-90℃ for 8-10h. After the reaction is completed, cool to room temperature, remove part of the solvent by vacuum distillation, add deionized water and precipitate the solid, filter to obtain crude product, dissolve the crude product in methanol, add sodium borohydride, stir and react at 25-40℃ for 2-3h. After the reaction is completed, adjust the pH to 6-7 with dilute hydrochloric acid, precipitate the solid, filter, wash with water until neutral, and vacuum dry to obtain intermediate B; S3. Add intermediate B and chlorine-terminated polydimethylsiloxane to a reaction vessel, add toluene to dissolve, then add triethylamine, and stir the reaction at 60-80℃ for 5-7 hours; after the reaction is completed, filter to remove triethylamine hydrochloride, and remove the solvent by vacuum distillation of the filtrate to obtain the modified organosilicon monomer.

[0008] Further, the preparation process of the polyurethane prepolymer is as follows: aliphatic isocyanate and polymeric polyol are added to a reaction vessel at a molar ratio of -NCO to -OH of 1.2-1.8:1, ethyl acetate is used as solvent, the amount of solvent is 2-3 times the total mass of the reactants, and dibutyltin dilaurate is added as a catalyst at a mass of 0.05-0.1% of the total mass of the reactants. The mixture is stirred and reacted at 60-75℃ for 3-4 hours to obtain the polyurethane prepolymer.

[0009] Further, in step S1, the feeding ratio of 5-amino-2-(2-chloro-4-aminophenyl)-benzoxazole, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, anhydrous ethanol, and glacial acetic acid is 10-20g: 8.6-19.0g: 70-240mL: 0.09-0.38mL.

[0010] Further, in step S2, the feeding ratio of intermediate A, glutamic acid, N,N-dimethylformamide, and anhydrous potassium carbonate is 10-20g: 3.3-7.2g: 55-170mL: 0.5-1.6g; and in step S2, the feeding ratio of crude product, methanol, and sodium borohydride is 10-20g: 60-200mL: 12-30g.

[0011] Further, in step S3, the feeding ratio of intermediate B, chlorinated polydimethylsiloxane, toluene, and triethylamine is 10-20g: 12.5-26.2g: 75-260mL: 11-24g.

[0012] Furthermore, the feeding ratio of the aliphatic isocyanate, polymeric polyol, ethyl acetate, and dibutyltin dilaurate is 10.1-30.2g: 50-100g: 130-440mL: 0.03-0.13g.

[0013] Further, the aliphatic isocyanate is at least one of hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and methylcyclohexyl diisocyanate; the polymeric polyol is at least one of polycarbonate diol, polytetrahydrofuran ether diol, polycaprolactone diol, and polypropylene glycol.

[0014] Furthermore, the small molecule polyol is at least one selected from 1,4-butanediol, 1,6-hexanediol, ethylenediamine, and diethylene glycol.

[0015] Furthermore, the silane coupling agent is at least one of KH-792, KH-560, and KH570.

[0016] On the other hand, the present invention also provides a method for preparing high-transparency, crack-resistant microcrystalline glass, comprising the following steps: (1) Add polyurethane prepolymer, small molecule polyol, nano silica, silane coupling agent and dibutyltin dilaurate into a stirred tank according to the formula. Stir at 300-500 rpm for 20-40 min under inert gas protection at 40-60℃ to make it uniformly mixed. Then add modified organosilicon monomer and continue stirring for 30-60 min to obtain coating liquid. (2) The surface of the microcrystalline glass substrate is cleaned and then activated by ultraviolet light irradiation; (3) The coating liquid is uniformly coated on the surface of the surface-activated microcrystalline glass substrate by spin coating, and the wet film thickness is controlled to be 50-150μm; the coated substrate is pre-cured at 60-80℃ for 10-30min, and then finally cured at 80-120℃ for 1-3h, and naturally cooled to room temperature to obtain the high transparency crack-resistant microcrystalline glass.

[0017] The beneficial effects of this invention are: This invention coats microcrystalline glass with a coating liquid containing polyurethane prepolymer, nano-silica, modified organosilicon monomers, and other components, giving the microcrystalline glass advantages such as high transparency, excellent crack resistance, good wear resistance, long-term stability, and hydrophobicity and antifouling properties.

[0018] The rigid structure of benzoxazole in the modified organosilicon monomer significantly enhances the mechanical strength and impact resistance of the coating, effectively resisting stress transmission and reducing crack formation under external forces. Simultaneously, the regularity of its aromatic ring structure helps reduce light scattering, ensuring the coating's high transparency. 5-Amino-2-(2-chloro-4-aminophenyl)-benzoxazole and 3,5-di-tert-butyl-4-hydroxybenzaldehyde form C=N bonds through a Schiff base reaction, introducing a hindered phenolic structure. As a highly efficient antioxidant, the hindered phenol can capture free radicals generated during coating aging, delaying the oxidative degradation of polyurethane, organosilicon, and other polymer chains, improving the coating's weather resistance and service life, and maintaining stable crack resistance and transparency over the long term. The carboxyl group introduced after the reaction of intermediate A with glutamic acid can undergo a dehydration condensation reaction with the hydroxyl groups on the surface of nano-silica, achieving uniform dispersion of nano-silica in the coating solution. To avoid light scattering and mechanical property degradation caused by particle agglomeration, the combination of carboxyl and hydroxyl groups makes nano-silica a rigid support point in the coating. With its high specific surface area and high hardness, it further improves the wear resistance and compressive strength of the coating, and synergistically enhances the crack resistance. After the crude product obtained from intermediate A is reduced, the C=N bond in the Schiff base structure is converted into a secondary amine group. On the one hand, the secondary amine group can undergo an addition reaction with the -NCO group in the polyurethane prepolymer, increasing the crosslinking density of the coating and forming a dense and tough crosslinking network, which improves the integrity and tensile strength of the coating. On the other hand, the siloxane flexible segments introduced by the reaction of the secondary amine group with chlorine-terminated polydimethylsiloxane can alleviate stress concentration inside the coating and inhibit crack propagation. At the same time, the low surface energy of the siloxane segments gives the coating hydrophobic and antifouling properties, reducing the adhesion of pollutants such as dust and water stains, without affecting the light transmittance of the coating.

[0019] The polyurethane prepolymer is prepared using aliphatic isocyanates and specific polyols. The aliphatic isocyanates avoid the yellowing defect of aromatic isocyanates and can maintain the transparency of the coating for a long time. The polyols give the polyurethane segments good flexibility and mechanical compatibility, forming a synergistic effect of rigidity and flexibility with the rigid structure in the modified organosilicon monomer and the flexible segments of siloxane, balancing the crack resistance and toughness of the coating and avoiding brittle cracking caused by excessive rigidity. Attached Figure Description

[0020] Figure 1 The following is the process equation for the preparation of the modified organosilicon monomer of this invention; Figure 2 The modified organosilicon monomer of this invention 1 HNMR image.

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0024] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the experimental materials used in the following examples were all purchased from commercial sources. The preparation process equations for the modified organosilicon monomers in the following examples are shown below. Figure 1 .

[0025] Example 1:

[0026] A high-transparency, crack-resistant microcrystalline glass includes a microcrystalline glass substrate and a crack-resistant coating; the crack-resistant coating comprises the following components in parts by weight: 50 parts polyurethane prepolymer, 5 parts nano-silica, 10 parts modified organosilicon monomer, 2 parts small molecule polyol, 0.1 parts dibutyltin dilaurate, and 1 part silane coupling agent.

[0027] The modified organosilicon monomer is prepared by the following steps: S1. 5-Amino-2-(2-chloro-4-aminophenyl)benzoxazole and 3,5-di-tert-butyl-4-hydroxybenzaldehyde were added to anhydrous ethanol, and glacial acetic acid was added dropwise as a catalyst. The mixture was stirred at 40°C for 4 hours. After the reaction was completed, the mixture was cooled to room temperature, and a solid was precipitated. The solid was filtered, washed three times with anhydrous ethanol, and dried under vacuum to obtain intermediate A. S2. Intermediate A and glutamic acid were added to N,N-dimethylformamide, anhydrous potassium carbonate was added, and the mixture was stirred at 70°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature, and some of the solvent was removed by vacuum distillation. After adding deionized water, a solid was precipitated and filtered to obtain the crude product. The crude product was dissolved in methanol, sodium borohydride was added, and the mixture was stirred at 25°C for 2 hours. After the reaction was completed, the pH was adjusted to 6-7 with dilute hydrochloric acid, and a solid was precipitated. The solid was filtered, washed with water until neutral, and dried under vacuum to obtain intermediate B. S3. Add intermediate B and chlorine-terminated polydimethylsiloxane to a reaction vessel, add toluene to dissolve, then add triethylamine, and stir the reaction at 60°C for 5 hours. After the reaction is completed, filter to remove triethylamine hydrochloride, and remove the solvent by vacuum distillation of the filtrate to obtain the modified organosilicon monomer.

[0028] The preparation process of the polyurethane prepolymer is as follows: Aliphatic isocyanate and polymeric polyol are added to a reaction vessel at a molar ratio of -NCO to -OH of 1.2:1. Ethyl acetate is used as a solvent, and the amount of solvent is twice the total mass of the reactants. Dibutyltin dilaurate, accounting for 0.05% of the total mass of the reactants, is added as a catalyst. The mixture is stirred at 60°C for 3 hours to obtain the polyurethane prepolymer.

[0029] In step S1, the feeding ratio of 5-amino-2-(2-chloro-4-aminophenyl)benzoxazole, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, anhydrous ethanol, and glacial acetic acid is 10g:8.6g:70mL:0.09mL.

[0030] In step S2, the feeding ratio of intermediate A, glutamic acid, N,N-dimethylformamide, and anhydrous potassium carbonate is 10g:3.3g:55mL:0.5g; and the feeding ratio of crude product, methanol, and sodium borohydride in step S2 is 10g:60mL:12g.

[0031] In step S3, the feeding ratio of intermediate B, chlorinated polydimethylsiloxane, toluene, and triethylamine is 10g:12.5g:75mL:11g.

[0032] The feeding ratio of the aliphatic isocyanate, polymeric polyol, ethyl acetate, and dibutyltin dilaurate is 10.1g:50g:130mL:0.03g.

[0033] The aliphatic isocyanate is hexamethylene diisocyanate; the polymeric polyol is polycarbonate diol; the small molecule polyol is 1,4-butanediol; and the silane coupling agent is KH-792.

[0034] A method for preparing a high-transparency, crack-resistant microcrystalline glass includes the following steps: (1) Add polyurethane prepolymer, small molecule polyol, nano silica, silane coupling agent and dibutyltin dilaurate into a stirred tank according to the ratio, and stir at 300 rpm for 20 min under inert gas protection at 40℃ to make it uniform; then add modified organosilicon monomer and continue stirring for 30 min to obtain coating liquid. (2) The surface of the microcrystalline glass substrate is cleaned and then activated by ultraviolet light irradiation; (3) The coating liquid is uniformly coated on the surface of the surface-activated microcrystalline glass substrate by spin coating, and the wet film thickness is controlled to be 50 μm. The coated substrate is pre-cured at 60°C for 10 min, and then finally cured at 80°C for 1 h. After natural cooling to room temperature, the high transparency crack-resistant microcrystalline glass is obtained.

[0035] Example 2:

[0036] A high-transparency, crack-resistant microcrystalline glass includes a microcrystalline glass substrate and a crack-resistant coating; the crack-resistant coating comprises the following components in parts by weight: 80 parts polyurethane prepolymer, 15 parts nano-silica, 30 parts modified organosilicon monomer, 5 parts small molecule polyol, 1 part dibutyltin dilaurate, and 3 parts silane coupling agent.

[0037] The modified organosilicon monomer is prepared by the following steps: S1. 5-Amino-2-(2-chloro-4-aminophenyl)benzoxazole and 3,5-di-tert-butyl-4-hydroxybenzaldehyde were added to anhydrous ethanol, and glacial acetic acid was added dropwise as a catalyst. The mixture was stirred at 60°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, and a solid was precipitated. The solid was filtered, washed three times with anhydrous ethanol, and dried under vacuum to obtain intermediate A. S2. Intermediate A and glutamic acid were added to N,N-dimethylformamide, anhydrous potassium carbonate was added, and the mixture was stirred at 90°C for 10 h. After the reaction was completed, the mixture was cooled to room temperature, and some of the solvent was removed by vacuum distillation. After adding deionized water, a solid was precipitated and filtered to obtain the crude product. The crude product was dissolved in methanol, sodium borohydride was added, and the mixture was stirred at 40°C for 3 h. After the reaction was completed, the pH was adjusted to 6-7 with dilute hydrochloric acid, and a solid was precipitated. The solid was filtered, washed with water until neutral, and dried under vacuum to obtain intermediate B. S3. Add intermediate B and chlorine-terminated polydimethylsiloxane to a reaction vessel, add toluene to dissolve, then add triethylamine, and stir the reaction at 80°C for 7 hours. After the reaction is completed, filter to remove triethylamine hydrochloride, and remove the solvent by vacuum distillation of the filtrate to obtain the modified organosilicon monomer.

[0038] The preparation process of the polyurethane prepolymer is as follows: Aliphatic isocyanate and polymeric polyol are added to a reaction vessel at a molar ratio of -NCO to -OH of 1.8:1. Ethyl acetate is used as a solvent, and the amount of solvent is 3 times the total mass of the reactants. Dibutyltin dilaurate, accounting for 0.1% of the total mass of the reactants, is added as a catalyst. The mixture is stirred at 75°C for 4 hours to obtain the polyurethane prepolymer.

[0039] In step S1, the feeding ratio of 5-amino-2-(2-chloro-4-aminophenyl)-benzoxazole, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, anhydrous ethanol, and glacial acetic acid is 20g:19.0g:240mL:0.38mL.

[0040] In step S2, the feeding ratio of intermediate A, glutamic acid, N,N-dimethylformamide, and anhydrous potassium carbonate is 20g:7.2g:170mL:1.6g; and the feeding ratio of crude product, methanol, and sodium borohydride in step S2 is 20g:200mL:30g.

[0041] In step S3, the feeding ratio of intermediate B, chlorine-terminated polydimethylsiloxane, toluene, and triethylamine is 20g:26.2g:260mL:24g.

[0042] The feeding ratio of the aliphatic isocyanate, polymeric polyol, ethyl acetate, and dibutyltin dilaurate is 30.2g:100g:440mL:0.13g.

[0043] The aliphatic isocyanate is a combination of hexamethylene diisocyanate and isophorone diisocyanate in a 1:1 mass ratio; the polymeric polyol is a combination of polycarbonate diol and polytetrahydrofuran ether diol in a 1:1 mass ratio; the small molecule polyol is a combination of 1,4-butanediol and 1,6-hexanediol in a 1:1 mass ratio; and the silane coupling agent is a combination of KH-792 and KH-560 in a 1:1 mass ratio.

[0044] A method for preparing a high-transparency, crack-resistant microcrystalline glass includes the following steps: (1) Add polyurethane prepolymer, small molecule polyol, nano silica, silane coupling agent and dibutyltin dilaurate into a stirred tank according to the ratio, and stir at 500 rpm for 40 min at 60℃ under inert gas protection to make it uniform; then add modified organosilicon monomer and continue stirring for 60 min to obtain coating liquid. (2) The surface of the microcrystalline glass substrate is cleaned and then activated by ultraviolet light irradiation; (3) The coating liquid is uniformly coated on the surface of the surface-activated microcrystalline glass substrate by spin coating, and the wet film thickness is controlled to be 150 μm. The coated substrate is pre-cured at 80°C for 30 min, and then finally cured at 120°C for 3 h. After natural cooling to room temperature, the high transparency crack-resistant microcrystalline glass is obtained.

[0045] Example 3:

[0046] A high-transparency, crack-resistant microcrystalline glass includes a microcrystalline glass substrate and a crack-resistant coating; the crack-resistant coating comprises the following components in parts by weight: 65 parts polyurethane prepolymer, 10 parts nano-silica, 20 parts modified organosilicon monomer, 3.5 parts small molecule polyol, 0.5 parts dibutyltin dilaurate, and 2 parts silane coupling agent.

[0047] The modified organosilicon monomer is prepared by the following steps: S1. 5-Amino-2-(2-chloro-4-aminophenyl)benzoxazole and 3,5-di-tert-butyl-4-hydroxybenzaldehyde were added to anhydrous ethanol, and glacial acetic acid was added dropwise as a catalyst. The mixture was stirred at 50°C for 5 hours. After the reaction was completed, the mixture was cooled to room temperature, and a solid was precipitated. The solid was filtered, washed three times with anhydrous ethanol, and dried under vacuum to obtain intermediate A. S2. Intermediate A and glutamic acid were added to N,N-dimethylformamide, anhydrous potassium carbonate was added, and the mixture was stirred at 80°C for 9 h. After the reaction was completed, the mixture was cooled to room temperature, and part of the solvent was removed by vacuum distillation. After adding deionized water, a solid was precipitated and filtered to obtain the crude product. The crude product was dissolved in methanol, sodium borohydride was added, and the mixture was stirred at 32°C for 2.5 h. After the reaction was completed, the pH was adjusted to 6-7 with dilute hydrochloric acid, and a solid was precipitated. The solid was filtered, washed with water until neutral, and dried under vacuum to obtain intermediate B. S3. Add intermediate B and chlorine-terminated polydimethylsiloxane to a reaction vessel, add toluene to dissolve, then add triethylamine, and stir the reaction at 70°C for 6 hours. After the reaction is completed, filter to remove triethylamine hydrochloride, and remove the solvent by vacuum distillation of the filtrate to obtain the modified organosilicon monomer.

[0048] The preparation process of the polyurethane prepolymer is as follows: Aliphatic isocyanate and polymeric polyol are added to a reaction vessel at a molar ratio of -NCO to -OH of 1.5:1. Ethyl acetate is used as solvent, and the amount of solvent is 2.5 times the total mass of the reactants. Dibutyltin dilaurate, accounting for 0.075% of the total mass of the reactants, is added as a catalyst. The mixture is stirred at 67°C for 3.5 hours to obtain the polyurethane prepolymer.

[0049] In step S1, the feeding ratio of 5-amino-2-(2-chloro-4-aminophenyl)benzoxazole, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, anhydrous ethanol, and glacial acetic acid is 15g:13.8g:155mL:0.235mL.

[0050] In step S2, the feeding ratio of intermediate A, glutamic acid, N,N-dimethylformamide, and anhydrous potassium carbonate is 15g:5.25g:112.5mL:1.05g; and the feeding ratio of crude product, methanol, and sodium borohydride in step S2 is 15g:130mL:21g.

[0051] In step S3, the feeding ratio of intermediate B, chlorinated polydimethylsiloxane, toluene, and triethylamine is 15g:19.35g:167.5mL:17.5g.

[0052] The feeding ratio of the aliphatic isocyanate, polyol, ethyl acetate, and dibutyltin dilaurate is 20.15g:75g:285mL:0.08g.

[0053] The aliphatic isocyanate is a combination of isophorone diisocyanate and 4,4'-dicyclohexylmethane diisocyanate in a 1:1 mass ratio; the polymeric polyol is a combination of polytetrahydrofuran ether diol and polycaprolactone diol in a 1:1 mass ratio; the small molecule polyol is a combination of 1,6-hexanediol and ethylenediamine in a 1:1 mass ratio; and the silane coupling agent is a combination of KH-560 and KH570 in a 1:1 mass ratio.

[0054] A method for preparing a high-transparency, crack-resistant microcrystalline glass includes the following steps: (1) Add polyurethane prepolymer, small molecule polyol, nano silica, silane coupling agent and dibutyltin dilaurate into a stirred tank according to the ratio, and stir at 400 rpm for 30 min at 50℃ under inert gas protection to make it uniform; then add modified organosilicon monomer and continue stirring for 45 min to obtain coating liquid. (2) The surface of the microcrystalline glass substrate is cleaned and then activated by ultraviolet light irradiation; (3) The coating liquid is uniformly coated on the surface of the surface-activated microcrystalline glass substrate by spin coating, and the wet film thickness is controlled to be 100 μm. The coated substrate is pre-cured at 70°C for 20 min, and then finally cured at 100°C for 2 h. After natural cooling to room temperature, the high transparency crack-resistant microcrystalline glass is obtained.

[0055] Comparative Example 1: The modified organosilicon monomer component is omitted in the crack-resistant coating of this comparative example; all other components are the same as in Example 3.

[0056] Comparative Example 2: The nano-silica component is omitted in the crack-resistant coating of this comparative example, and the rest is the same as in Example 3.

[0057] Comparative Example 3: In this comparative example, commercially available ordinary hydroxyl-terminated polydimethylsiloxane was used instead of the modified organosilicon monomer, and all other aspects were the same as in Example 3.

[0058] Results Analysis The modified organosilicon monomer prepared in this invention was characterized by nuclear magnetic resonance, and the results are shown in the figure. Figure 2 . Figure 2 In the above, the proton peak at 0.15 ppm is the proton peak of the methyl group on dimethylsiloxane, the proton peak at 1.37 ppm is the proton peak of the tert-butyl group, the proton peak at 4.32 ppm is the proton peak of the methylene group after the reduction of the C=N bond generated by the Schiff base reaction, and the proton peaks at 12.02 ppm and 12.39 ppm are the proton peaks of the carboxyl group introduced by glutamic acid. In summary, this invention proves that the preparation of the above-mentioned product... Figure 1 Modified organosilicon monomers with medium structure.

[0059] The microcrystalline glass prepared by this invention was tested for transparency, impact resistance, wear resistance, weather resistance, and hydrophobicity.

[0060] According to GB / T2410-2008, the transmittance was tested using a UV-Vis spectrophotometer. The specific steps are as follows: The samples prepared in Examples 1-3 and Comparative Examples 1-3 were cut into 50mm×50mm×2mm test pieces, placed in the sample chamber of the spectrophotometer, and scanned in the wavelength range of 400-800nm ​​using air as a reference. The transmittance value at a wavelength of 550nm was recorded.

[0061] According to GB / T6552-2015, the impact resistance performance was tested using a falling ball impact tester. The specific steps are as follows: 100mm×100mm×5mm samples prepared in Examples 1-3 and Comparative Examples 1-3 were placed on the impact tester platform. A steel ball with a diameter of 19mm and a mass of 100g was used to drop freely from different heights to impact the center position of the sample. The critical impact height at which visible cracks appeared on the sample surface was recorded.

[0062] According to ASTM D1044-2013, wear performance was tested using a Taber abrasion tester. The specific steps are as follows: 100mm×100mm×5mm samples prepared in Examples 1-3 and Comparative Examples 1-3 were fixed on a rotating platform. A CS-10 grinding wheel was used, a load of 500g was applied, and the sample was rotated 1000 times at a speed of 60r / min. The mass of the sample was weighed using an electronic balance with an accuracy of 0.1mg before and after the test, and the mass wear rate was calculated.

[0063] Accelerated aging tests were conducted in accordance with GB / T16422.3-2014 using an ultraviolet aging test chamber. The specific steps are as follows: 50mm×50mm×2mm samples prepared in Examples 1-3 and Comparative Examples 1-3 were placed in the aging chamber and subjected to UVB-313 lamps. After continuous ultraviolet irradiation at 60℃ for 8 hours, the samples were condensed at 50℃ for 4 hours as one cycle. A total of 500 hours of aging tests were conducted, and the change in transmittance of the samples at 550nm before and after aging was tested.

[0064] According to GB / T30447-2013, the water contact angle was tested using a contact angle measuring instrument. The specific steps are as follows: The 50mm×50mm×2mm samples prepared in Examples 1-3 and Comparative Examples 1-3 were placed horizontally on the measuring platform. 5μL of deionized water was added to the sample surface using a micro-syringe. The droplet morphology was analyzed and the static water contact angle was calculated using the instrument's built-in software.

[0065] Table 1 Comparison of Performance Test Results of Glass-Crystal

[0066] According to the test results in Table 1, the high-transparency crack-resistant microcrystalline glass prepared by this invention exhibits excellent comprehensive performance. Examples 1-3 all maintained a transmittance of over 86.5% at a wavelength of 550nm, demonstrating outstanding optical performance. The critical impact height of each example exceeded 50cm, significantly higher than the comparative examples, showing excellent impact resistance. Abrasion resistance tests showed that the mass wear rate of the examples remained below 12.3mg / 1000r, far lower than the 25.0mg / 1000r of comparative example 2, proving that both nano-silica and modified organosilicon monomers enhanced abrasion resistance. After 500 hours of accelerated aging, the transmittance change of the examples was less than 2.2%, indicating that the modified organosilicon monomers have anti-aging advantages. In the hydrophobicity test, the water contact angle of each example was greater than 102°, significantly higher than the comparative examples, demonstrating good hydrophobic properties. In summary, these data fully verify that the present invention successfully achieves improvements in high transparency, crack resistance, wear resistance, weather resistance, and hydrophobicity through the synergistic effect of polyurethane prepolymer, nano-silica, and modified organosilicon monomers.

[0067] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0068] The present invention and its embodiments have been described above. This description is not restrictive, and the embodiments shown are only one of the embodiments of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A high-transparency, crack-resistant microcrystalline glass, characterized in that: It includes a microcrystalline glass substrate and a crack-resistant coating; the crack-resistant coating comprises the following components in parts by weight: 50-80 parts of polyurethane prepolymer, 5-15 parts of nano-silica, 10-30 parts of modified organosilicon monomer, 2-5 parts of small molecule polyol, 0.1-1 parts of dibutyltin dilaurate, and 1-3 parts of silane coupling agent. The modified organosilicon monomer is prepared by the following steps: S1. 5-Amino-2-(2-chloro-4-aminophenyl)benzoxazole and 3,5-di-tert-butyl-4-hydroxybenzaldehyde were added to anhydrous ethanol, and glacial acetic acid was added dropwise as a catalyst. The mixture was stirred at 40-60℃ for 4-6 hours. After the reaction was completed, the mixture was cooled to room temperature, and a solid was precipitated. The solid was filtered, washed three times with anhydrous ethanol, and dried under vacuum to obtain intermediate A. S2. Add intermediate A and glutamic acid to N,N-dimethylformamide, add anhydrous potassium carbonate, stir and react at 70-90℃ for 8-10h. After the reaction is completed, cool to room temperature, remove part of the solvent by vacuum distillation, add deionized water and precipitate the solid, filter to obtain crude product, dissolve the crude product in methanol, add sodium borohydride, stir and react at 25-40℃ for 2-3h. After the reaction is completed, adjust the pH to 6-7 with dilute hydrochloric acid, precipitate the solid, filter, wash with water until neutral, and vacuum dry to obtain intermediate B; S3. Add intermediate B and chlorine-terminated polydimethylsiloxane to a reaction vessel, add toluene to dissolve, then add triethylamine, and stir the reaction at 60-80℃ for 5-7 hours; after the reaction is completed, filter to remove triethylamine hydrochloride, and remove the solvent by vacuum distillation of the filtrate to obtain the modified organosilicon monomer.

2. The high-transparency, crack-resistant microcrystalline glass according to claim 1, characterized in that: The preparation process of the polyurethane prepolymer is as follows: Aliphatic isocyanate and polymeric polyol are added to a reaction vessel at a molar ratio of -NCO to -OH of 1.2-1.8:

1. Ethyl acetate is used as solvent, and the amount of solvent is 2-3 times the total mass of the reactants. Dibutyltin dilaurate is added as a catalyst at a mass of 0.05-0.1% of the total mass of the reactants. The mixture is stirred and reacted at 60-75℃ for 3-4 hours to obtain the polyurethane prepolymer.

3. The high-transparency, crack-resistant microcrystalline glass according to claim 2, characterized in that: In step S1, the feeding ratio of 5-amino-2-(2-chloro-4-aminophenyl)benzoxazole, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, anhydrous ethanol, and glacial acetic acid is 10-20g: 8.6-19.0g: 70-240mL: 0.09-0.38mL.

4. The high-transparency, crack-resistant microcrystalline glass according to claim 3, characterized in that: In step S2, the feeding ratio of intermediate A, glutamic acid, N,N-dimethylformamide, and anhydrous potassium carbonate is 10-20g: 3.3-7.2g: 55-170mL: 0.5-1.6g; the feeding ratio of crude product, methanol, and sodium borohydride in step S2 is 10-20g: 60-200mL: 12-30g.

5. The high-transparency, crack-resistant microcrystalline glass according to claim 4, characterized in that: In step S3, the feeding ratio of intermediate B, chlorinated polydimethylsiloxane, toluene, and triethylamine is 10-20g: 12.5-26.2g: 75-260mL: 11-24g.

6. The high-transparency, crack-resistant microcrystalline glass according to claim 5, characterized in that: The feeding ratio of the aliphatic isocyanate, polymeric polyol, ethyl acetate, and dibutyltin dilaurate is 10.1-30.2g: 50-100g: 130-440mL: 0.03-0.13g.

7. The high-transparency, crack-resistant microcrystalline glass according to claim 6, characterized in that: The aliphatic isocyanate is at least one of hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and methylcyclohexyl diisocyanate; the polymeric polyol is at least one of polycarbonate diol, polytetrahydrofuran ether diol, polycaprolactone diol, and polypropylene glycol.

8. The high-transparency, crack-resistant microcrystalline glass according to claim 7, characterized in that: The small molecule polyol is at least one of 1,4-butanediol, 1,6-hexanediol, ethylenediamine, and diethylene glycol.

9. The high-transparency, crack-resistant microcrystalline glass according to claim 8, characterized in that: The silane coupling agent is at least one of KH-792, KH-560, and KH570.

10. A method for preparing a high-transparency, crack-resistant microcrystalline glass according to any one of claims 1-9, characterized in that: Includes the following steps: (1) Add polyurethane prepolymer, small molecule polyol, nano silica, silane coupling agent and dibutyltin dilaurate into a stirred tank according to the formula. Stir at 300-500 rpm for 20-40 min under inert gas protection at 40-60℃ to make it uniformly mixed. Then add modified organosilicon monomer and continue stirring for 30-60 min to obtain coating liquid. (2) The surface of the microcrystalline glass substrate is cleaned and then activated by ultraviolet light irradiation; (3) The coating liquid is uniformly coated on the surface of the surface-activated microcrystalline glass substrate by spin coating, and the wet film thickness is controlled to be 50-150μm; the coated substrate is pre-cured at 60-80℃ for 10-30min, and then finally cured at 80-120℃ for 1-3h, and naturally cooled to room temperature to obtain the high transparency crack-resistant microcrystalline glass.

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