A microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure and a preparation method thereof

Abstract

The application discloses a microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure and a preparation method thereof, and belongs to the technical field of microcrystalline glass cover plates. From bottom to top, the microcrystalline glass anti-fingerprint cover plate comprises a microcrystalline glass base material, a porous silica anchoring intermediate layer and an anti-fingerprint layer. The porous silica anchoring intermediate layer is composed of hollow silica nanosphere stacks and has a three-dimensional interconnected nanopore structure, a porosity of 40%-60% and a thickness of 100-300 nm. Test results show that the microcrystalline glass cover plate prepared by the application has high hardness (>=8H pencil hardness), high wear resistance (resistance to steel wool friction >=25000 times) and excellent hydrophobic and stain-proof performance (water contact angle >=118° and oleic acid contact angle >=78°), and the anti-fingerprint life is more than three times that of conventional products, and the microcrystalline glass anti-fingerprint cover plate is particularly suitable for high-end electronic device screen cover plates.

Description

Technical Field

[0001] This invention relates to the field of microcrystalline glass cover technology, and more specifically, to a microcrystalline glass anti-fingerprint cover with a porous anchoring structure and its preparation method. Background Technology

[0002] With the widespread use of smartphones, tablets, and other electronic devices, the anti-fingerprint (AF) performance of their screen cover surfaces has become a key factor affecting user experience. Currently, the industry commonly uses a nano-coating formed by applying a perfluoropolyether-based anti-fingerprint liquid to the glass surface to provide hydrophobic and oleophobic effects.

[0003] However, conventional AF coatings have limited adhesion to the glass substrate, resulting in insufficient abrasion resistance and easy scratching and failure during use. Common AF coatings are PFPE (perfluoropolyether, a type of fluorinated polyether silicon oxide), such as Shin-Etsu anti-fingerprint liquid. While they can achieve a certain number of abrasion cycles, their film hardness is limited, and their performance deteriorates significantly with long-term use. PFPE films form valence bonds with the Si-O structure on the glass interface, but achieving high adhesion in microcrystalline glass is difficult. CN116589193A discloses a microcrystalline glass with a hydrophobic and oleophobic composite coating on its surface. This coating forms an underlayer, an intermediate layer, and a hydrophobic and oleophobic layer on the microcrystalline glass surface. The underlayer is a silicon oxide, the intermediate layer is an ionic crystal intermediate layer (fluorosilicide) with a lattice energy of 700-3000 kJ / mol, and the hydrophobic and oleophobic layer is a fluorinated polymer. Even with a small amount of Si-O structure at the coating interface of the microcrystalline glass or glass-ceramic, a strong, durable, and high-performance hydrophobic and oleophobic coating can be formed. However, this design is only applicable to PFPE films, and a single AF coating cannot simultaneously meet the requirements of high hardness, high wear resistance, and long-term hydrophobicity and anti-fouling properties of microcrystalline glass covers. CN120965099A discloses a method of forming dense nano-silica as an intermediate layer using magnetron sputtering, with Si-CH2 bonds formed between the SiO2 layer and the anti-fingerprint layer, thereby improving adhesion, but the material of the AF layer limits its use.

[0004] Therefore, it is necessary to develop a surface treatment solution that can match the high strength properties of microcrystalline glass and has long-lasting anti-fingerprint properties, high wear resistance, and high hardness. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, this invention provides a microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure and its preparation method. By stacking hollow silica to form an anchoring intermediate layer, the adhesion between the AF layer and the microcrystalline glass is improved, thereby increasing the service life of the microcrystalline glass cover plate.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A microcrystalline glass anti-fingerprint cover with a porous anchoring structure comprises, from bottom to top, a microcrystalline glass substrate, a porous silica anchoring intermediate layer, and an anti-fingerprint layer. The porous silica anchoring intermediate layer is composed of stacked hollow silica nanospheres, has a three-dimensional interconnected nanopore structure, a porosity of 40%-60%, and a thickness of 100-300 nm.

[0008] Preferably, the hollow silica nanospheres have an average particle size of 50-100 nm and a shell thickness of 10-20 nm.

[0009] Preferably, the anti-fingerprint layer is a hybrid system of fluorinated modified acrylate polymer and nano-silica, with a thickness of 100-500 nm.

[0010] Preferably, the fluorinated acrylate polymer has a weight-average molecular weight of 50,000-200,000; the nano-silica has a particle size of 5-15 nm, and its surface is modified with a silane coupling agent.

[0011] Preferably, the method for preparing the porous silica anchoring intermediate layer includes: dispersing hollow silica nanospheres in an alcohol-water mixed solvent to form a uniform dispersion with a solid content of 5%-10%; coating it on the surface of a substrate; and sintering it at 450-550℃ for 30-60 minutes to form a porous silica anchoring intermediate layer.

[0012] Preferably, the microcrystalline glass substrate is a microcrystalline glass substrate that has undergone ion exchange in KNO3 molten salt and surface strengthening.

[0013] Preferably, the surface compressive stress of the reinforced microcrystalline glass substrate is ≥700 MPa.

[0014] A method for preparing a microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure, comprising:

[0015] S1. Substrate pretreatment and strengthening:

[0016] The microcrystalline glass substrate is cleaned and dried, and then surface-strengthened by ion exchange in KNO3 molten salt.

[0017] S2. Construct a porous silica anchoring intermediate layer:

[0018] Hollow silica nanospheres are dispersed in an alcohol-water mixed solvent to form a uniform dispersion with a solid content of 5%-10%; coated onto the surface of a substrate; and sintered at 450-550℃ for 30-60 minutes to form a porous silica anchoring intermediate layer.

[0019] S3. Preparation of fluorosilicone polymer hybrid anti-fingerprint layer:

[0020] Fluorine-modified acrylate monomers, crosslinking agents, photoinitiators, and surface-modified nano-silica are dispersed in an organic solvent to form a coating liquid. The coating liquid is applied to the porous silica anchoring intermediate layer and allowed to stand to allow the liquid to fully penetrate into the pores. UV pre-curing is performed, followed by heat curing at 120-150℃ for 1-2 hours to form a crosslinked hybrid anti-fingerprint layer.

[0021] An electronic device comprising the aforementioned microcrystalline glass anti-fingerprint cover as a display screen or protective cover.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. Improved Adhesion: The porous silica anchoring intermediate layer provides a strong physical anchoring (mechanical interlocking) effect for the AF layer. Combined with chemical bonding, the adhesion of the AF layer reaches level 0 (cross-cut test), fundamentally solving the problem of peeling.

[0024] 2. Excellent durability and toughness: The interpenetrating network structure formed by the inorganic porous framework and organic polymer gives the composite membrane both high hardness and high toughness. Its wear resistance is increased to more than 20,000 cycles, and it can withstand more than 100,000 dynamic bending cycles.

[0025] 3. Long-lasting protective performance: The dense hybrid AF layer and the stable anchoring structure ensure the long-term stability of hydrophobic and oleophobic properties, and the performance degradation is extremely low after harsh environmental testing (high temperature and humidity, acid and alkali immersion).

[0026] 4. Good process compatibility: The preparation method requires conventional equipment and has a wide process parameter window, making it suitable for large-scale industrial production. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the microcrystalline glass cover plate of the present invention.

[0028] Figure 2 The diagram shows the process (left) and result (right) of the water droplet angle test of the microcrystalline glass cover plate prepared in Example 1 of the present invention. Detailed Implementation

[0029] Numerous specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many other ways than those described herein, and similar modifications can be made by those skilled in the art without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0031] It should be noted that, unless otherwise specified, the raw materials, instruments, etc. involved in this invention are all commercially available products.

[0032] Example 1

[0033] One embodiment of this invention provides a microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure, such as... Figure 1 As shown, its structure, from bottom to top, includes a microcrystalline glass substrate, a porous silica anchoring interlayer, and an anti-fingerprint layer. The porous silica anchoring interlayer is composed of stacked hollow silica nanospheres and has a three-dimensional interconnected nanoporous structure. Its preparation method includes the following steps:

[0034] S1. Substrate preparation: Commercially available lithium aluminum silicon microcrystalline glass (Corning Gorilla Glass type) is used, cut to the required size, cleaned and dried, and then ion-exchanged in KNO3 molten salt at 410℃ for 6 hours to obtain a reinforced microcrystalline glass substrate with a surface compressive stress of about 750 MPa.

[0035] S2. Preparation of a porous anchoring intermediate layer:

[0036] Hollow silica nanospheres with an average particle size of 80 nm were dispersed in a mixed solvent of ethanol and deionized water (volume ratio 9:1) to prepare a dispersion with a solid content of 7 wt%.

[0037] The dispersion was uniformly coated onto the reinforced substrate using a slot coater, with the wet film thickness controlled at 50 μm.

[0038] The coated substrate was placed in a muffle furnace and sintered at 500°C for 45 minutes. After natural cooling, a porous silica anchoring intermediate layer with a thickness of about 200 nm and a porosity of about 50% was obtained.

[0039] S3. Fabrication of hybrid AF layer:

[0040] Preparation of coating solution: 50g of fluorinated modified acrylate monomer (CYTOP® analogue) (purchased from Shanghai Yangshi Industrial Co., Ltd., the same below), 1g of dipentaerythritol pentaacrylate (crosslinking agent), 0.5g of photoinitiator (Irgacure 184) and 5g of nano-silica (particle size 10 nm) modified with KH-570 silane coupling agent (purchased from Jiangxi Chenguang New Materials Co., Ltd., the same below) were dispersed in 50g of perfluorohexane solvent and ultrasonically stirred until uniform.

[0041] The coating solution is applied to the porous intermediate layer by microgravure coating and left to stand at room temperature for 5 minutes to allow the solution to fully penetrate.

[0042] First, the sample was pre-cured by irradiating it with a UV lamp (intensity: 80 mW / cm²) for 30 seconds under nitrogen protection; then the sample was placed in an oven and heat-cured at 130°C for 1.5 hours to form a fluorosilicone polymer hybrid anti-fingerprint layer with a thickness of about 300 nm.

[0043] Example 2

[0044] One embodiment of this invention provides a microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure, such as... Figure 1 As shown, its structure, from bottom to top, includes a microcrystalline glass substrate, a porous silica anchoring interlayer, and an anti-fingerprint layer. The porous silica anchoring interlayer is composed of stacked hollow silica nanospheres and has a three-dimensional interconnected nanoporous structure. Its preparation method includes the following steps:

[0045] S1. Substrate preparation:

[0046] Similar to the steps in Example 1, commercially available lithium aluminum silicon microcrystalline glass was used. After cutting and cleaning, it was ion-exchanged in KNO3 molten salt at 410°C for 6 hours to obtain a reinforced substrate with a surface compressive stress of approximately 750 MPa.

[0047] S2. Preparation of porous anchoring intermediate layer:

[0048] Hollow silica nanospheres with an average particle size of 60 nm were dispersed in a mixed solvent of ethanol and deionized water (volume ratio 9:1) to prepare a dispersion with a solid content of 6 wt%.

[0049] The dispersion was coated onto the substrate using a slot coater, and the wet film thickness was controlled at 40 μm by adjusting the coating parameters.

[0050] The coated substrate was placed in a muffle furnace and sintered at 480°C for 60 minutes; after natural cooling, a porous silica anchoring intermediate layer with a thickness of approximately 150 nm and a porosity of approximately 55% was obtained. Smaller nanospheres and a slightly lower sintering temperature contribute to the formation of a denser porous structure with smaller pore sizes.

[0051] S3. Preparation of hybrid AF layer:

[0052] Preparation of coating solution: 48g of fluorinated modified acrylate monomer, 1.2g of another multifunctional acrylate crosslinking agent (pentaerythritol tetraacrylate), 0.5g of photoinitiator (Irgacure184) and 4g of nano-silica (particle size 10nm) modified with KH-570 on the surface are dispersed in 48g of perfluorohexane solvent and ultrasonically stirred until uniform.

[0053] The coating liquid is applied to the porous intermediate layer by microgravure coating and left to stand at room temperature for 5 minutes.

[0054] Pre-curing is performed by irradiating with a UV lamp (intensity: 80mW / cm²) for 25 seconds under nitrogen protection.

[0055] The sample was then placed in an oven and heat-cured at 125°C for 2 hours to form a fluorosilicone polymer hybrid anti-fingerprint layer with a thickness of approximately 250 nm.

[0056] Example 3

[0057] One embodiment of this invention provides a microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure, such as... Figure 1 As shown, its structure, from bottom to top, includes a microcrystalline glass substrate, a porous silica anchoring interlayer, and an anti-fingerprint layer. The porous silica anchoring interlayer is composed of stacked hollow silica nanospheres and has a three-dimensional interconnected nanoporous structure. Its preparation method includes the following steps:

[0058] S1. Substrate preparation:

[0059] Same as in Example 1, a reinforced microcrystalline glass substrate was obtained.

[0060] S2. Preparation of porous anchoring intermediate layer:

[0061] Hollow silica nanospheres with an average particle size of 100 nm were dispersed in a mixed solvent of ethanol and deionized water (volume ratio 8:1) to prepare a dispersion with a solid content of 8.5 wt%.

[0062] Slot coating was used, and the wet film thickness was controlled at 60 μm.

[0063] Sinter at 520°C for 40 minutes in a muffle furnace;

[0064] After natural cooling, a porous silica anchoring intermediate layer with a thickness of approximately 280 nm and a porosity of approximately 45% is obtained.

[0065] S3. Preparation of hybrid AF layer:

[0066] Preparation of coating solution:

[0067] Main monomer: A mixture of 40g of fluorinated modified acrylate monomer and 10g of a fluorinated acrylate oligomer was used to adjust the cohesive strength and toughness of the film after formation.

[0068] Crosslinking agent: 1.5g dipentaerythritol pentaacrylate;

[0069] Additives: Add 0.3g leveling agent (BYK-333);

[0070] Nanofiller: 6g of KH-570-modified nano-silica (particle size 10nm).

[0071] Solvent: A mixed solvent of 45g perfluorohexane and 5g methylpentanone.

[0072] The coating solution is applied to the porous intermediate layer using the dip-coating method (an alternative to microgravure coating), and allowed to stand at room temperature for 8 minutes to allow for more sufficient penetration time.

[0073] The UV pre-curing conditions are the same as in Example 1 (80mW / cm², 30 seconds).

[0074] The thermosetting conditions were changed to curing at 140℃ for 1 hour to form a hybrid anti-fingerprint layer with a thickness of about 350nm.

[0075] Comparative Example 1

[0076] The same microcrystalline glass substrate as in Example 1 was used, but Shin-Etsu KY-1905 anti-fingerprint liquid was directly coated on its surface to form an AF coating.

[0077] Comparative Example 2

[0078] The difference from Example 1 is that step S2 is not performed.

[0079] Comparative Example 3

[0080] The difference from Example 1 is that in step S2, hollow nano-silica is replaced with ordinary nano-silica with an average particle size of 80 nm.

[0081] Comparative Example 4

[0082] The difference from Example 1 is that the nano-silica in step S3 is not surface modified.

[0083] Comparative Example 5

[0084] The difference from Example 1 is that nano-silica is not used in step S3.

[0085] Comparative Example 6

[0086] The difference from Example 1 is that in step S3, Shin-Etsu KY-1905 anti-fingerprint liquid is directly coated on the intermediate layer to form an AF coating.

[0087] The samples obtained in Example 1 and Comparative Example 1 were subjected to the following tests, and the test methods and results are recorded in Table 1.

[0088] As shown in Table 1, Examples 1-3 exhibit equally excellent adhesion (Grade 0). Due to the smaller and more uniform pore size of the intermediate layer, the hybrid AF layer forms a dense interpenetrating network after penetration and anchoring, resulting in superior chemical corrosion resistance (such as sweat and alkali resistance) and initial hydrophobic angle. The abrasion life has increased from the industry-common 5000 cycles to over 25000 cycles, achieving a breakthrough increase of more than 5 times. The performance retention rate after alkali resistance testing shows an order-of-magnitude advantage. In Comparative Example 1, Shin-Etsu KY-1905 anti-fingerprint liquid (PTFE type) was directly used as the AF layer, resulting in poor hardness and abrasion resistance. In Comparative Example 2, the AF layer from the examples was formed directly on the reinforced microcrystalline glass, significantly reducing abrasion resistance and alkali resistance. In Comparative Example 3, ordinary nano-silica was used. Ordinary nano-silica cannot form a hollow three-dimensional stacked structure and is unevenly dispersed, leading to reduced adhesion. In Comparative Example 4, the unmodified nano-silica in the AF layer resulted in significantly reduced hardness, wear resistance, and alkali resistance. This is because the unmodified nano-silica disperses unevenly in the fluoropolymer and exhibits weak bonding, leading to defects and reduced density on the coating surface. In Comparative Example 6, although the water droplet angle and fingerprint resistance were improved by incorporating hollow nano-silica into the anchoring interlayer, the improvement was minimal. This is because the extreme chemical inertness and insolubility of PTFE prevent it from forming a dense interpenetrating network with the anchoring interlayer.

[0089] Table 1 Performance Test Results

[0090]

[0091] The aforementioned data advantage stems from the unique triple structural design of this invention: "microcrystalline glass - porous silica anchoring layer - fluorosilicone polymer hybrid AF layer," which is fundamentally different from the comparative example.

[0092] 1. The technological effect represents a qualitative leap: the wear resistance life has increased from the industry-common 5,000 cycles to over 25,000 cycles, achieving a breakthrough increase of more than 5 times. The performance retention rate after alkali resistance testing also shows an order-of-magnitude advantage.

[0093] 2. The effect stems from specific structural features: The aforementioned remarkable effect is directly attributed to the specific structural feature of the "porous anchoring intermediate layer composed of stacked hollow silica nanospheres." This feature is not present in other technologies and has not been explored in existing techniques.

[0094] 3. Unexpected technical effects: When pursuing high wear resistance, those skilled in the art typically enhance the hardness or cross-linking degree of the AF coating itself, but this often comes at the cost of adhesion or toughness. This invention, by introducing a porous intermediate layer, unexpectedly achieves a comprehensive improvement in adhesion, wear resistance, hardness, and chemical resistance simultaneously; this synergistic effect is unforeseen.

Claims

1. A microcrystalline glass anti-fingerprint cover with a porous anchoring structure, characterized in that, From bottom to top, it includes a microcrystalline glass substrate, a porous silica anchoring intermediate layer, and an anti-fingerprint layer. The porous silica anchoring intermediate layer is composed of hollow silica nanospheres sintered and stacked, with a three-dimensional interconnected nanoporous structure, a porosity of 40%-60%, and a thickness of 100-300 nm. The anti-fingerprint layer is a hybrid system of fluorine-modified acrylate polymer and nano-silica. The surface of the nano-silica is modified with a silane coupling agent.

2. The microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure according to claim 1, characterized in that, The hollow silica nanospheres have an average particle size of 50-100 nm and a shell thickness of 10-20 nm.

3. The microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure according to claim 1, characterized in that, The thickness of the anti-fingerprint layer is 100-500 nm.

4. The microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure according to claim 3, characterized in that, The weight-average molecular weight of the fluorinated modified acrylate polymer is 50,000-200,000; the particle size of the nano-silica is 5-15 nm.

5. The microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure according to claim 1, characterized in that, The method for preparing the porous silica anchoring intermediate layer includes: dispersing hollow silica nanospheres in an alcohol-water mixed solvent to form a uniform dispersion with a solid content of 5%-10%; coating it on the surface of a substrate; and sintering it at 450-550℃ for 30-60 minutes to form a porous silica anchoring intermediate layer.

6. The microcrystalline glass anti-fingerprint cover with a porous anchoring structure according to any one of claims 1-5, characterized in that, The microcrystalline glass substrate is a microcrystalline glass substrate that has undergone ion exchange in KNO3 molten salt and surface strengthening.

7. The microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure according to claim 6, characterized in that, The surface compressive stress of the reinforced microcrystalline glass substrate is ≥700 MPa.

8. A method for preparing a microcrystalline glass anti-fingerprint cover plate with a porous anchoring structure according to any one of claims 1-7, characterized in that, include: S1. Substrate pretreatment and strengthening: The microcrystalline glass substrate is cleaned and dried, and then surface-strengthened by ion exchange in KNO3 molten salt. S2. Construct a porous silica anchoring intermediate layer: Hollow silica nanospheres are dispersed in an alcohol-water mixed solvent to form a uniform dispersion with a solid content of 5%-10%; coated onto the surface of a substrate; and sintered at 450-550℃ for 30-60 minutes to form a porous silica anchoring intermediate layer. S3. Preparation of fluorosilicone polymer hybrid anti-fingerprint layer: Fluorine-modified acrylate monomers, crosslinking agents, photoinitiators, and surface-modified nano-silica are dispersed in an organic solvent to form a coating liquid. The coating liquid is applied to the porous silica anchoring intermediate layer and allowed to stand to allow the liquid to fully penetrate into the pores. UV pre-curing is performed, followed by heat curing at 120-150℃ for 1-2 hours to form a crosslinked hybrid anti-fingerprint layer.

9. An electronic device, characterized in that, The microcrystalline glass anti-fingerprint cover plate as described in any one of claims 1-7 is used as a display screen or protective cover plate.

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