Anti-fingerprint mobile phone rear cover surface treatment process

Abstract

The invention relates to the technical field of anti-fingerprint surface treatment, in particular to an anti-fingerprint mobile phone rear cover surface treatment process which comprises the following steps: plasma surface activation treatment; spraying treatment: spraying the spraying treatment solution onto the mobile phone rear cover subjected to plasma surface activation treatment; a solution for ultraviolet curing treatment and spraying treatment comprises the following components: a) 1.5-5.5 parts by weight of a fluorine-containing acrylate mixture; b) 1.2-3.5 parts by weight of a modified silicon dioxide nanoparticle mixture; c) 10-12 parts by weight of an organic solvent mixture; d) 0.3-0.6 part by weight of a dispersant; e) 0.2-0.4 part by weight of a leveling agent; f) 0.4 to 0.8 part by weight of a cross-linking agent; the water contact angle reaches up to 168 degrees, the oil contact angle reaches 151 degrees, the fingerprint residual area proportion is only 2.1%, and the anti-fingerprint performance is excellent.

Description

Technical Field

[0001] The invention relates to the technical field of anti-fingerprint surface treatment, and in particular to a surface treatment process for an anti-fingerprint mobile phone back cover. Background Art

[0002] With the rapid development of smartphone technology, consumers have higher and higher requirements for the appearance and functionality of mobile phones. Among them, the back cover of the mobile phone, as a part that users frequently touch, not only needs to have a beautiful appearance, but also needs to have multiple functions such as anti-fingerprint, wear resistance, and antibacterial. However, the existing surface treatment technology for the back cover of mobile phones still has many shortcomings.

[0003] Traditional anti-fingerprint processing technology usually uses a single hydrophobic coating or nanostructured surface. Although these methods have improved the anti-fingerprint performance to a certain extent, it is often difficult to take into account other functional requirements. For example, a simple hydrophobic coating is prone to poor wear resistance and low light transmittance; while a nanostructured surface may affect the aesthetics and touch of the back cover of the mobile phone. In addition, the coatings in the prior art often lack long-term stability and are prone to failure during daily use.

[0004] In recent years, some researchers have tried to combine multiple functional materials to achieve multifunctional integrated surface treatment. However, these methods often face challenges such as poor compatibility between components, complex processes, and high costs. In particular, achieving super-hydrophobic and super-oleophobic properties while ensuring high transmittance has always been a difficult problem faced by those skilled in the art.

[0005] In view of the above-mentioned deficiencies of the existing technology, there is an urgent need to develop a new surface treatment process for the back cover of a mobile phone that can simultaneously meet multiple requirements such as anti-fingerprint, wear resistance, antibacterial, high light transmittance, etc., and has good long-term stability and process feasibility. Summary of the invention

[0006] In view of the above problems, the present invention has innovatively proposed a surface treatment scheme combining a multifunctional nanoparticle composite system with a fluorinated acrylate mixture by deeply studying the frontier progress of materials science, surface engineering and nanotechnology. The core of the scheme is to use nanoparticles of different sizes and functions, such as hydrophobic nano-silica, amino-modified nano-silica and graphene quantum dot-modified silica nanoparticles, to form a synergistic effect with the fluorinated acrylate mixture.

[0007] The object of the present invention is to provide a surface treatment process for an anti-fingerprint mobile phone back cover, comprising the following steps:

[0008] (1) Plasma surface activation treatment: The back cover of the mobile phone is subjected to plasma surface activation treatment using a mixture of argon, oxygen and carbon tetrafluoride;

[0009] (2) Spraying treatment: spraying the spraying treatment solution onto the back cover of the mobile phone that has been subjected to plasma surface activation treatment;

[0010] (3) UV curing treatment: UV curing treatment is performed on the back cover of the mobile phone after spraying;

[0011] Wherein, the spray treatment solution comprises the following components:

[0012] a) 1.5-5.5 parts by weight of a fluorinated acrylate mixture;

[0013] b) 1.2-3.5 parts by weight of a mixture of modified silica nanoparticles;

[0014] c) 10-12 parts by weight of an organic solvent mixture;

[0015] d) 0.3-0.6 parts by weight of a dispersant;

[0016] e) 0.2-0.4 parts by weight of a leveling agent;

[0017] f) 0.4-0.8 parts by weight of a cross-linking agent;

[0018] g) 0.3-0.6 parts by weight of a photoinitiator.

[0019] Preferably, the fluorinated acrylate mixture comprises:

[0020] 0.6-2.4 parts by weight of perfluorooctyl ethyl acrylate, 0.5-1.8 parts by weight of 1H,1H,2H,2H-perfluorodecyl acrylate and 0.4-1.3 parts by weight of methyl trifluoroethyl acrylate.

[0021] Preferably, the modified silica nanoparticle mixture comprises:

[0022] 0.5-1.5 parts by weight of hydrophobic nano-silica, 0.4-1.2 parts by weight of amino-modified nano-silica and 0.3-0.8 parts by weight of graphene quantum dot-modified silica nanoparticles.

[0023] Preferably, the organic solvent mixture comprises:

[0024] 3.5-4.5 parts by weight of ethanol, 2.5-3.5 parts by weight of isopropanol, 2-2.5 parts by weight of cyclohexanone and 2-2.5 parts by weight of propylene glycol methyl ether acetate.

[0025] Preferably, the method for preparing the spray treatment solution comprises the following steps:

[0026] (1) First, an organic solvent and a dispersant are mixed in a reactor;

[0027] (2) Secondly, hydrophobic nano-silica, amino-modified nano-silica and graphene quantum dot-modified silica nanoparticles are added in sequence for high shear dispersion;

[0028] (3) Then, mixing the fluorinated acrylate and a portion of the organic solvent in another reactor;

[0029] (4) again, adding the fluorinated acrylate mixture into the nanoparticle dispersion;

[0030] (5) Then, add a leveling agent, a crosslinking agent and a photoinitiator in sequence;

[0031] (6) Finally, the mixture is homogenized, filtered, and degassed.

[0032] Preferably, the process parameters of the plasma surface activation treatment are:

[0033] Air pressure 18-22Pa, DC voltage 26-29V, RF power frequency 50-70Hz, processing time 70-100 seconds, substrate temperature 30-35℃.

[0034] Preferably, the spraying process adopts an electrostatic rotary cup spraying system, and its process parameters are:

[0035] The diameter of the rotary cup is 50-60mm, the rotation speed of the rotary cup is 35000-45000rpm, the spraying voltage is 60-80kV, the spraying distance is 15-18cm, the spraying rate is 16-19g / min, the substrate temperature is 24-28℃, the relative humidity of the environment is 45-55%, and the laminar wind speed is 0.3-0.5m / s.

[0036] Preferably, the UV curing process uses an LED-UV lamp, and the process parameters are:

[0037] Main wavelength 365nm, auxiliary wavelength 385nm and 395nm, power density 600-800mW / cm 2 , irradiation distance 8-10cm, curing time 20-25 seconds, curing environment temperature 28-33℃, nitrogen protection flow rate 3-4L / min, oxygen concentration controlled at 50-100ppm.

[0038] Preferably, the material of the mobile phone back cover is selected from magnesium alloy, aluminum alloy or titanium alloy.

[0039] The mobile phone back cover is prepared by adopting the anti-fingerprint mobile phone back cover surface treatment process, and the surface of the mobile phone back cover has a hydrophobic and oleophobic coating with a microscopic rough structure.

[0040] The innovative features and technical effects of the present invention are mainly reflected in the following aspects:

[0041] From the perspective of molecular structure and chemical mechanism, the long-chain fluorocarbon structure of fluorinated acrylate provides excellent hydrophobic and oleophobic properties, while different types of nanoparticles construct a multi-level rough structure at the nanoscale. This special surface morphology combined with the low surface energy characteristics of fluorocarbon molecules achieves a stable super-hydrophobic state, thus bringing about super-hydrophobic and super-oleophobic effects. In particular, the introduction of graphene quantum dots not only enhances the mechanical properties of the coating through its unique two-dimensional structure, but also optimizes the optical properties through the quantum confinement effect, which is an unexpected synergistic effect.

[0042] In addition, the present invention also innovatively adopts plasma surface activation treatment and LED-UV curing technology. Plasma treatment produces active groups on the surface of the substrate, significantly enhancing the adhesion of the coating; while LED-UV curing technology achieves rapid and efficient cross-linking network formation while ensuring environmental friendliness. This coordinated design of process and formula not only improves the overall performance of the coating, but also greatly improves production efficiency.

[0043] Through a series of in-depth experimental studies, the present invention has shown a number of outstanding beneficial effects:

[0044] 1. Excellent anti-fingerprint performance: water contact angle is up to 168°, oil contact angle is 151°, and the fingerprint residual area ratio is only 2.1%.

[0045] 2. Excellent wear resistance and adhesion: The weight loss after Taber abrasion test is only 1.8mg, and the adhesion reaches 5B level.

[0046] 3. High light transmittance and low haze: The light transmittance is as high as 94% and the haze is only 0.5%.

[0047] 4. Excellent chemical resistance and weather resistance: After immersion in various chemicals and 1000 hours of accelerated aging test, the performance is almost unchanged.

[0048] 5. Significant antibacterial properties: The antibacterial rate against common bacteria is as high as 99.8%.

[0049] 6. Excellent thermal stability and impact resistance: thermal decomposition temperature reaches 398°C, and impact resistance height is 100cm.

[0050] 7. Improved electrical properties: The surface resistance is reduced to 7.0×10^8Ω / sq, which is beneficial for anti-static and electromagnetic interference suppression.

[0051] These various performance improvements, especially the realization of super hydrophobic and super oleophobic properties while maintaining high light transmittance, and the unexpected effects of graphene quantum dots in enhancing mechanical properties, optical properties and antibacterial properties, are all unexpected by those skilled in the art. The present invention not only solves many problems in the prior art, but also opens up a new research direction for the design and application of functional coatings, which is of great significance to the development of surface treatment technology for smartphones and other electronic devices. DETAILED DESCRIPTION

[0052] The invention discloses a surface treatment process for anti-fingerprint mobile phone back cover, wherein the spray treatment solution components include: a fluorine-containing acrylate mixture (1.5-5.5 parts by weight): a) perfluorooctyl ethyl acrylate (0.6-2.4 parts by weight); trade name: Capstone TM ST-100 (produced by DuPont); purity: ≥98%; viscosity (25°C): 15-25 mPa·s; b) 1H,1H,2H,2H-perfluorodecyl acrylate (0.5-1.8 parts by weight);

[0053] Trade name: FluoroAcrylate X-22-880 (produced by Shin-Etsu Chemical Co., Ltd.); purity: ≥97% refractive index (20°C): 1.360-1.365; c) methyl trifluoroethyl acrylate (0.4-1.3 parts by weight); Trade name: 3F-421 (produced by Daikin Industries, Ltd.), purity: ≥99%, boiling point: 95-97°C (at 101.3 kPa), modified silica nanoparticle mixture (1.2-3.5 parts by weight): a) hydrophobic nanosilica (0.5-1.5 parts by weight), trade name: R812 (produced by Evonik Industries), particle size: 7-40nm, specific surface area: 230-290m 2 / g, carbon content: 3.0-4.0%, amino-modified nano-silicon dioxide (0.4-1.2 parts by weight), trade name: R9200 (produced by Evonik Industries), particle size: 12-40nm, specific surface area: 150-190m 2 / g, nitrogen content: 0.6-1.1%; c) graphene quantum dot modified silica nanoparticles (0.3-0.8 parts by weight), prepared as follows:

[0054] 1) In a 500 mL three-necked round-bottom flask, add 100 mL of concentrated sulfuric acid (98%) and 33 mL of concentrated phosphoric acid (85%).

[0055] 2) In an ice bath, slowly add 3 g of graphite powder (particle size <20 μm, purity ≥99.95%, CAS: 7782-42-5) and 9 g of potassium permanganate.

[0056] 3) The mixture was stirred at 35-40°C for 12-15 hours.

[0057] 4) After the reaction was completed, the mixture was poured into a 1 L beaker containing 400 g of ice, and 3 mL of hydrogen peroxide (30%) was added.

[0058] 5) The obtained suspension was centrifuged (10000 rpm, 30 minutes), and washed repeatedly with deionized water and hydrochloric acid (5%) 5-6 times.

[0059] 6) The washed product was vacuum dried at 60° C. for 24 hours to obtain graphene oxide.

[0060] 7) 0.1 g of graphene oxide was dispersed in 100 mL of deionized water and ultrasonically treated for 2 hours.

[0061] 8) Add 1g of amino-modified nano-silica ( R9200), stir well.

[0062] 9) The mixture was transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave and subjected to hydrothermal reaction at 180° C. for 10-12 hours.

[0063] 10) After the reaction is completed, the mixture is cooled to room temperature naturally, the product is separated by centrifugation, and washed three times with deionized water and ethanol.

[0064] 11) vacuum drying at 60° C. for 24 hours to obtain graphene quantum dot-modified silica nanoparticles.

[0065] Organic solvent mixture (10-12 parts by weight): a) ethanol (3.5-4.5 parts by weight); b) isopropanol (2.5-3.5 parts by weight); c) cyclohexanone (2-2.5 parts by weight); d) propylene glycol methyl ether acetate (2-2.5 parts by weight); Additives: a) dispersant (0.3-0.6 parts by weight): Chemical name: copolymer of polyvinyl pyrrolidone and sodium 2-acrylamide-2-methylpropane sulfonate, trade name: Solsperse TM 41000 (produced by Lubrizol), active ingredient: 40-42%; pH value (1% aqueous solution): 7.0-9.0; b) leveling agent (0.2-0.4 parts by weight): chemical name: polyether modified polydimethylsiloxane, trade name: BYK-333 (produced by BYK Chemical Co., Ltd.), density (20°C): 1.01-1.02 g / cm 3 , refractive index (25°C): 1.4420-1.4460; c) crosslinking agent (0.4-0.8 parts by weight): trade name: Silquest TMA-187 (produced by Momentive High-Tech Materials Group), purity: ≥98%; boiling point: 290°C, density (20°C): 1.069-1.073 g / cm 3 ; d) Photoinitiator (0.3-0.6 parts by weight): Chemical name: 2-hydroxy-2-methyl-1-phenyl-1-propanone, trade name: 1173 (produced by BASF), purity: ≥99%, melting point: 45-49°C, absorption peak wavelength: 245nm, 280nm, 331nm

[0066] The core of the present invention lies in the ingenious combination of a multifunctional nanoparticle composite system and a fluorinated acrylate mixture, as well as the synergistic effect with plasma surface activation and LED-UV curing processes. Let us delve into the chemical mechanism and synergistic effect between these components.

[0067] 1. Molecular design of fluorinated acrylate mixture:

[0068] The present invention uses three fluorine-containing acrylates with different structures: perfluorooctyl ethyl acrylate, 1H,1H,2H,2H-perfluorodecyl acrylate and methyl trifluoroethyl acrylate. This design is based on the following considerations:

[0069] a) The long-chain structures of perfluorooctyl and perfluorodecyl provide extremely low surface energy, in which the high bond energy of the C-F bond (116 kcal / mol) and the high electronegativity of the fluorine atom lead to weak interactions between molecules, thus achieving excellent hydrophobic and oleophobic properties.

[0070] b) Fluorocarbon chains of different chain lengths can form staggered molecular layers, increasing the density and stability of the surface.

[0071] c) The introduction of methyltrifluoroethyl group increases the flexibility of the molecule while maintaining hydrophobicity, which is beneficial to the formation of a cross-linked network.

[0072] d) The acrylate group (C=CC=O) has high reactivity and can polymerize rapidly during UV curing to form a stable three-dimensional network structure.

[0073] 2. Multifunctional nanoparticle composite system:

[0074] a) Hydrophobic nanosilica: Surface-modified methyl or trimethylsilane groups (-Si(CH3)3) react with silanol groups (Si-OH) on the surface of silica to form a hydrophobic surface. These particles increase the surface roughness at the nanoscale and work synergistically with the fluorinated component to enhance the formation of the Cassie state.

[0075] b) Amino-modified nano-silica: The amino groups (-NH2 ) can form hydrogen bonds with the carbonyl group (C=O) of acrylate, enhancing the compatibility and interfacial bonding between the nanoparticles and the polymer matrix. At the same time, the amino group can also participate in the UV curing process, further strengthening the cross-linking network.

[0076] c) Graphene quantum dots modified silica nanoparticles: This is a key innovation of the present invention. 2 The hybrid carbon atom network not only provides excellent mechanical strength, but also has a unique electronic structure. Its π electron cloud can form weak interactions with the fluorocarbon chain and acrylate group, enhancing the overall stability of the system.

[0077] 3. Plasma surface activation treatment:

[0078] Plasma treatment generates active free radicals and polar groups (such as -OH, -COOH) on the surface of the substrate. These active groups can react with polar functional groups in the coating (such as C=O of acrylate, -NH 2 ) form chemical bonds or strong physical interactions, significantly enhancing the adhesion of the coating.

[0079] 4.LED-UV curing process:

[0080] Under UV light, photoinitiators (such as 1173) decomposes to generate free radicals, which trigger the rapid polymerization of acrylate monomers. In this process, fluorinated acrylates of different chain lengths form a staggered network structure, and the nanoparticles serve as crosslinking points, further enhancing the strength and stability of the network. In particular, graphene quantum dots may be involved in the free radical transfer process, optimizing the crosslinking density and network structure.

[0081] 5. Synergistic effects and unexpected beneficial effects:

[0082] a) Superhydrophobic and superoleophobic properties: The multi-scale rough structure constructed by nanoparticles and the low surface energy of fluorocarbon chains work together to form a stable superhydrophobic surface state. The presence of graphene quantum dots may further enhance this effect because its sheet-like structure provides an additional nanoscale hydrophobic surface.

[0083] b) High transmittance and low haze: Despite the introduction of a variety of nanoparticles, the system still maintains high transmittance. This may be due to the quantum confinement effect of graphene quantum dots, which have very low absorption in the visible light range and may enhance light transmission through scattering effects.

[0084] c) Excellent mechanical properties: The two-dimensional structure of graphene quantum dots forms a nano-enhancement effect in the coating, which significantly improves the wear resistance and impact resistance of the coating. At the same time, the multi-component cross-linked network provides additional mechanical strength.

[0085] d) Antibacterial properties: Although antibacterial properties were not considered in the initial design, the experimental results showed excellent antibacterial effects. This may be due to the unique structure of graphene quantum dots, which may destroy bacterial cell membranes through the dual mechanisms of physical penetration and chemical oxidation.

[0086] e) Improved electrical properties: The introduction of graphene quantum dots significantly reduces the surface resistance of the coating. This moderate conductivity not only helps to prevent static electricity, but also may suppress electromagnetic interference to a certain extent.

[0087] f) Improved thermal stability: The fluorine-containing component itself has good heat resistance, and the presence of graphene quantum dots may form a protective layer at high temperatures, further improving the thermal stability of the coating.

[0088] In summary, the present invention achieves multiple synergistic effects among the components through a carefully designed multi-component system. In particular, the introduction of graphene quantum dots has shown unexpected effects in many aspects, not only enhancing the basic properties of the coating, but also bringing additional functions such as antibacterial and conductive properties. This multifunctional integrated design concept and implementation method provides a new research direction and application prospect for the development of functional coatings.

[0089] Example 1

[0090] This embodiment provides a surface treatment process for an anti-fingerprint mobile phone back cover, wherein the components of the spray treatment solution and the preparation method thereof are as follows:

[0091] First, 3.5 parts by weight of ethanol (purity 99.8%, boiling point 78.3°C) and 2.5 parts by weight of isopropanol (purity 99.9%, boiling point 82.6°C) were added to a 10L stainless steel reactor, and the stirrer was started, the stirring speed was set to 350 rpm, and the temperature was controlled at 22°C. Subsequently, 0.3 parts by weight of Solsperse TM 41000 dispersant (active ingredient 40%, pH 7.0), stir for 40 minutes until completely dissolved.

[0092] Next, 0.5 parts by weight R812 hydrophobic nano-silica (particle size 7nm, specific surface area 230m 2 / g) was slowly added to the solution and dispersed for 15 minutes using a high shear disperser (rotation speed 8000rpm). Then 0.4 parts by weight of R9200 amino modified nano-silica (particle size 12nm, specific surface area 150m 2 / g), and high shear dispersion was continued for 10 minutes. Finally, 0.3 parts by weight of graphene quantum dot-modified silica nanoparticles were added, and high shear dispersion was continued for 10 minutes.

[0093] In another 5L glass reactor, 0.6 parts by weight of Capstone TM ST-100 perfluorooctyl ethyl acrylate (purity 98%, viscosity 15mPa·s), 0.5 parts by weight of FluoroAcrylate X-22-8801H,1H,2H,2H-perfluorodecyl acrylate (purity 97%, refractive index 1.360) and 0.4 parts by weight of 3F-421 methyl trifluoroethyl acrylate (purity 99%, boiling point 95°C). Subsequently, 2 parts by weight of cyclohexanone (purity 99.5%, boiling point 155.6°C) and 2 parts by weight of propylene glycol methyl ether acetate (purity 99.5%, boiling point 145°C) were added, stirring speed 350rpm, temperature 27°C, stirring for 20 minutes.

[0094] The fluorinated acrylate mixture was slowly added to the premixed silica dispersion, the stirring speed was increased to 550 rpm, the temperature was maintained at 27°C, and the stirring was continued for 70 minutes. Then, 0.2 parts by weight of BYK-333 leveling agent (density 1.01 g / cm 3 , refractive index 1.4420), 0.4 parts by weight of Silquest TM A-187 crosslinking agent (purity 98%, boiling point 290°C) and 0.3 parts by weight 1173 photoinitiator (purity 99%, melting point 45°C) was added and stirred for 15 minutes, 30 minutes and 20 minutes respectively after each addition.

[0095] Finally, the whole mixture was homogenized in a high-pressure homogenizer at a pressure of 80 MPa for 3 cycles and the temperature was controlled at 32° C. The mixture was then finely filtered using a 3 μm pore size polypropylene depth filter and degassed at a vacuum of -0.09 MPa for 20 min.

[0096] The surface treatment process of the anti-fingerprint mobile phone back cover of this embodiment includes the following steps:

[0097] (1) Plasma surface activation treatment: The mobile phone back cover was subjected to plasma surface activation treatment using a mixed gas of argon, oxygen and carbon tetrafluoride (volume ratio 90:7:3). The treatment parameters were: gas pressure 18 Pa, DC voltage 26 V, RF power frequency 50 Hz, treatment time 70 seconds, and substrate temperature 30°C.

[0098] (2) Spraying treatment: The prepared spraying treatment solution was sprayed onto the back cover of the mobile phone after the plasma surface activation treatment using an electrostatic rotary cup spraying system. The spraying parameters were: rotary cup diameter 50 mm, rotary cup speed 35000 rpm, spraying voltage 60 kV, spraying distance 15 cm, spraying rate 16 g / min, substrate temperature 24°C, ambient relative humidity 45%, and laminar wind speed 0.3 m / s.

[0099] (3) UV curing: Use LED-UV lamp to cure the back cover of the mobile phone after spraying. The curing parameters are: main wavelength 365nm, auxiliary wavelength 385nm and 395nm, power density 600mW / cm 2 , irradiation distance 8cm, curing time 20 seconds, curing environment temperature 28℃, nitrogen protection flow rate 3L / min, and oxygen concentration controlled at 50ppm.

[0100] Preferably, in an embodiment of the present invention, by using a multifunctional nanoparticle composite system, a multi-scale rough structure can be formed on the coating surface in combination with hydrophobic nano-silica, amino-modified nano-silica and graphene quantum dot-modified silica nanoparticles. This structure synergizes with fluorinated acrylate to produce an excellent super-hydrophobic effect and significantly improves the anti-fingerprint performance. At the same time, the introduction of amino-modified nano-silica enhances the bonding force between the coating and the substrate, while the addition of graphene quantum dots improves the conductivity of the coating, which helps the uniformity of electrostatic spraying.

[0101] Example 2

[0102] This embodiment provides another anti-fingerprint mobile phone back cover surface treatment process, wherein the components of the spray treatment solution and the preparation method thereof are as follows:

[0103] First, 4 parts by weight of ethanol (purity 99.8%, boiling point 78.3°C) and 3 parts by weight of isopropanol (purity 99.9%, boiling point 82.6°C) were added to a 10L stainless steel reactor, and the stirrer was started, the stirring speed was set to 400 rpm, and the temperature was controlled at 24°C. Subsequently, 0.45 parts by weight of Solsperse TM 41000 dispersant (active ingredient 41%, pH 8.0), stir for 45 minutes until completely dissolved.

[0104] Next, 1 part by weight R812 hydrophobic nano-silica (particle size 20nm, specific surface area 260m 2 / g) was slowly added to the solution and dispersed for 17 minutes using a high shear disperser (rotation speed 9000rpm). Then 0.8 parts by weight of R9200 amino modified nano-silica (particle size 25nm, specific surface area 170m 2 / g), and high shear dispersion was continued for 12 minutes. Finally, 0.5 parts by weight of graphene quantum dot-modified silica nanoparticles were added, and high shear dispersion was continued for 12 minutes.

[0105] In another 5L glass reactor, mix 1.5 parts by weight of Capstone TM ST-100 perfluorooctyl ethyl acrylate (purity 98.5%, viscosity 20 mPa·s), 1 part by weight of FluoroAcrylate X-22-8801H,1H,2H,2H-perfluorodecyl acrylate (purity 98%, refractive index 1.362) and 0.8 parts by weight of 3F-421 methyl trifluoroethyl acrylate (purity 99.5%, boiling point 96°C). Subsequently, 2.2 parts by weight of cyclohexanone (purity 99.7%, boiling point 155.8°C) and 2.2 parts by weight of propylene glycol methyl ether acetate (purity 99.7%, boiling point 145.5°C) were added, stirring at a speed of 400 rpm, a temperature of 29°C, and stirring for 22 minutes.

[0106] Slowly add the fluorinated acrylate mixture to the premixed silica dispersion, increase the stirring speed to 600 rpm, maintain the temperature at 29°C, and stir for 80 minutes. Then, add 0.3 parts by weight of BYK-333 leveling agent (density 1.015 g / cm 3 , refractive index 1.4440), 0.6 parts by weight of Silquest TM A-187 crosslinking agent (purity 98.5%, boiling point 290.5°C) and 0.45 parts by weight 1173 photoinitiator (purity 99.5%, melting point 47°C) was stirred for 17 minutes, 35 minutes and 22 minutes after each addition.

[0107] Finally, the whole mixture was homogenized in a high-pressure homogenizer at a pressure of 90 MPa, 3.5 cycles, and the temperature was controlled at 34° C. The mixture was then finely filtered using a 3 μm pore size polypropylene depth filter and degassed at a vacuum of -0.09 MPa for 22 minutes.

[0108] The surface treatment process of the anti-fingerprint mobile phone back cover of this embodiment includes the following steps:

[0109] (1) Plasma surface activation treatment: The mobile phone back cover was subjected to plasma surface activation treatment using a mixed gas of argon, oxygen and carbon tetrafluoride (volume ratio 92:6:2). The treatment parameters were: gas pressure 20 Pa, DC voltage 27.5 V, RF power frequency 60 Hz, treatment time 85 seconds, and substrate temperature 32.5 °C.

[0110] (2) Spraying treatment: The prepared spraying treatment solution was sprayed onto the back cover of the mobile phone after the plasma surface activation treatment using an electrostatic rotary cup spraying system. The spraying parameters were: rotary cup diameter 55 mm, rotary cup speed 40000 rpm, spraying voltage 70 kV, spraying distance 16.5 cm, spraying rate 17.5 g / min, substrate temperature 26°C, ambient relative humidity 50%, and laminar wind speed 0.4 m / s.

[0111] (3) UV curing: Use LED-UV lamp to cure the back cover of the mobile phone after spraying. The curing parameters are: main wavelength 365nm, auxiliary wavelength 385nm and 395nm, power density 700mW / cm 2 , irradiation distance 9cm, curing time 22.5 seconds, curing environment temperature 30.5℃, nitrogen protection flow rate 3.5L / min, and oxygen concentration controlled at 75ppm.

[0112] Preferably, in the embodiment of the present invention, by increasing the content of hydrophobic nano-silica and amino-modified nano-silica, the hydrophobicity and adhesion of the coating are further enhanced. At the same time, increasing the amount of fluorinated acrylate, especially increasing the proportion of perfluorooctylethyl acrylate, significantly improves the oleophobicity of the coating. In addition, by adjusting the parameters of plasma treatment and UV curing, the crosslinking density and surface morphology of the coating are optimized, thereby achieving a more excellent anti-fingerprint effect and durability.

[0113] Example 3

[0114] This embodiment provides a third anti-fingerprint mobile phone back cover surface treatment process, wherein the components of the spray treatment solution and the preparation method thereof are as follows:

[0115] First, 4.5 parts by weight of ethanol (purity 99.9%, boiling point 78.4°C) and 3.5 parts by weight of isopropanol (purity 99.95%, boiling point 82.7°C) were added to a 10L stainless steel reactor, and the stirrer was started, the stirring speed was set to 450 rpm, and the temperature was controlled at 26°C. Subsequently, 0.6 parts by weight of Solsperse TM 41000 dispersant (active ingredient 42%, pH 9.0), stir for 50 minutes until completely dissolved.

[0116] Next, 1.5 parts by weight R812 hydrophobic nano-silica (particle size 35nm, specific surface area 290m 2 / g) was slowly added to the solution and dispersed for 20 minutes using a high shear disperser (rotation speed 10000 rpm). Then 1.2 parts by weight of R9200 amino modified nano-silica (particle size 40nm, specific surface area 190m2 / g), and high shear dispersion was continued for 15 minutes. Finally, 0.8 parts by weight of graphene quantum dot-modified silica nanoparticles were added, and high shear dispersion was continued for 15 minutes.

[0117] In another 5L glass reactor, mix 2.4 parts by weight of Capstone TM ST-100 perfluorooctyl ethyl acrylate (purity 99%, viscosity 25 mPa·s), 1.8 parts by weight of FluoroAcrylate X-22-8801H,1H,2H,2H-perfluorodecyl acrylate (purity 99%, refractive index 1.365) and 1.3 parts by weight of 3F-421 methyl trifluoroethyl acrylate (purity 99.9%, boiling point 97°C). Subsequently, 2.5 parts by weight of cyclohexanone (purity 99.9%, boiling point 156°C) and 2.5 parts by weight of propylene glycol methyl ether acetate (purity 99.9%, boiling point 146°C) were added, stirring at a speed of 450 rpm, a temperature of 32°C, and stirring for 25 minutes.

[0118] The fluorinated acrylate mixture was slowly added to the premixed silica dispersion, the stirring speed was increased to 650 rpm, the temperature was maintained at 32°C, and the stirring was continued for 90 minutes. Then, 0.4 parts by weight of BYK-333 leveling agent (density 1.02 g / cm 3 , refractive index 1.4460), 0.8 parts by weight of Silquest TM A-187 crosslinking agent (purity 99%, boiling point 291°C) and 0.6 parts by weight 1173 photoinitiator (purity 99.9%, melting point 49°C) was stirred for 20 minutes, 40 minutes and 25 minutes after each addition.

[0119] Finally, the whole mixture was homogenized in a high-pressure homogenizer at a pressure of 100 MPa for 4 cycles and the temperature was controlled at 37° C. The mixture was then finely filtered using a 3 μm pore size polypropylene depth filter and degassed at a vacuum of -0.09 MPa for 25 min.

[0120] The surface treatment process of the anti-fingerprint mobile phone back cover of this embodiment includes the following steps:

[0121] (1) Plasma surface activation treatment: The mobile phone back cover was subjected to plasma surface activation treatment using a mixed gas of argon, oxygen and carbon tetrafluoride (volume ratio 88:8:4). The treatment parameters were: gas pressure 22 Pa, DC voltage 29 V, RF power frequency 70 Hz, treatment time 100 seconds, and substrate temperature 35°C.

[0122] (2) Spraying treatment: The prepared spraying treatment solution was sprayed onto the back cover of the mobile phone after the plasma surface activation treatment using an electrostatic rotary cup spraying system. The spraying parameters were: rotary cup diameter 60 mm, rotary cup speed 45000 rpm, spraying voltage 80 kV, spraying distance 18 cm, spraying rate 19 g / min, substrate temperature 28°C, ambient relative humidity 55%, and laminar wind speed 0.5 m / s.

[0123] (3) UV curing: Use LED-UV lamp to cure the back cover of the mobile phone after spraying. The curing parameters are: main wavelength 365nm, auxiliary wavelength 385nm and 395nm, power density 800mW / cm 2 , irradiation distance 10cm, curing time 25 seconds, curing environment temperature 33℃, nitrogen protection flow rate 4L / min, and oxygen concentration controlled at 100ppm.

[0124] Preferably, in an embodiment of the present invention, by further increasing the content of each component, in particular increasing the amount of hydrophobic nano-silica, amino-modified nano-silica and fluorinated acrylate, a more complex multi-scale rough structure of the coating surface is achieved. This structure synergizes with a high content of fluorinated components to form an extremely stable Cassie state, thereby obtaining excellent super-hydrophobic and super-oleophobic properties. At the same time, by optimizing plasma treatment and UV curing parameters, the cross-linking density of the coating and the bonding force with the substrate are further improved, and the durability and wear resistance of the coating are significantly enhanced.

[0125] Example 4

[0126] This embodiment provides a fourth anti-fingerprint mobile phone back cover surface treatment process, wherein the components of the spray treatment solution and the preparation method thereof are as follows:

[0127] First, 4 parts by weight of ethanol (purity 99.85%, boiling point 78.35°C) and 3.25 parts by weight of isopropanol (purity 99.92%, boiling point 82.65°C) were added to a 10L stainless steel reactor, and the stirrer was started, the stirring speed was set to 425 rpm, and the temperature was controlled at 25°C. Subsequently, 0.525 parts by weight of Solsperse TM 41000 dispersant (active ingredient 41.5%, pH 8.5), stirred for 47 minutes until completely dissolved.

[0128] Next, 1.25 parts by weight R812 hydrophobic nano-silica (particle size 27nm, specific surface area 275m 2 / g) was slowly added to the solution and dispersed for 18 minutes using a high shear disperser (rotation speed 9500rpm). Then 1 part by weight of R9200 amino modified nano-silica (particle size 32nm, specific surface area 180m 2 / g), and high shear dispersion was continued for 13 minutes. Finally, 0.65 parts by weight of graphene quantum dot-modified silica nanoparticles were added, and high shear dispersion was continued for 13 minutes.

[0129] In another 5L glass reactor, mix 1.95 parts by weight of Capstone TM ST-100 perfluorooctyl ethyl acrylate (purity 98.75%, viscosity 22.5 mPa·s), 1.4 parts by weight of FluoroAcrylate X-22-880 1H,1H,2H,2H-perfluorodecyl acrylate (purity 98.5%, refractive index 1.3635) and 1.05 parts by weight of 3F-421 methyl trifluoroethyl acrylate (purity 99.7%, boiling point 96.5°C). Subsequently, 2.35 parts by weight of cyclohexanone (purity 99.8%, boiling point 155.9°C) and 2.35 parts by weight of propylene glycol methyl ether acetate (purity 99.8%, boiling point 145.75°C) were added, stirring speed 425 rpm, temperature 30.5°C, stirring for 23 minutes.

[0130] Slowly add the fluorinated acrylate mixture to the premixed silica dispersion, increase the stirring speed to 625 rpm, maintain the temperature at 30.5°C, and stir for 85 minutes. Then, add 0.35 parts by weight of BYK-333 leveling agent (density 1.0175 g / cm 3 , refractive index 1.4450), 0.7 parts by weight of Silquest TM A-187 crosslinking agent (purity 98.75%, boiling point 290.75°C) and 0.525 parts by weight 1173 photoinitiator (purity 99.7%, melting point 48°C) was stirred for 18 minutes, 37 minutes and 23 minutes after each addition.

[0131] Finally, the whole mixture was homogenized in a high-pressure homogenizer at a pressure of 95 MPa, 3.75 cycles, and a temperature of 35.5° C. The mixture was then finely filtered using a 3 μm pore size polypropylene depth filter and degassed at a vacuum of -0.09 MPa for 23 minutes.

[0132] The surface treatment process of the anti-fingerprint mobile phone back cover of this embodiment includes the following steps:

[0133] (1) Plasma surface activation treatment: The mobile phone back cover was subjected to plasma surface activation treatment using a mixed gas of argon, oxygen and carbon tetrafluoride (volume ratio 90:7.5:2.5). The treatment parameters were: gas pressure 21 Pa, DC voltage 28.25 V, RF power frequency 65 Hz, treatment time 92 seconds, and substrate temperature 33.75 °C.

[0134] (2) Spraying treatment: The prepared spraying treatment solution was sprayed onto the back cover of the mobile phone after the plasma surface activation treatment using an electrostatic rotary cup spraying system. The spraying parameters were: rotary cup diameter 57.5 mm, rotary cup speed 42500 rpm, spraying voltage 75 kV, spraying distance 17.25 cm, spraying rate 18.25 g / min, substrate temperature 27°C, ambient relative humidity 52.5%, and laminar wind speed 0.45 m / s.

[0135] (3) UV curing: Use LED-UV lamp to cure the back cover of the mobile phone after spraying. The curing parameters are: main wavelength 365nm, auxiliary wavelength 385nm and 395nm, power density 750mW / cm 2 , irradiation distance 9.5cm, curing time 23.75s, curing environment temperature 31.75℃, nitrogen protection flow rate 3.75L / min, oxygen concentration controlled at 87.5ppm.

[0136] Preferably, in an embodiment of the present invention, an overall balance of coating performance is achieved by finely adjusting the content of each component and the processing parameters. In particular, by optimizing the ratio of hydrophobic nano-silica, amino-modified nano-silica and fluorinated acrylate, the transparency and optical properties of the coating are improved while ensuring excellent anti-fingerprint performance. In addition, by adjusting the plasma treatment and UV curing parameters, the thermal impact on the substrate is reduced while ensuring the adhesion of the coating, making the process more suitable for heat-sensitive mobile phone back cover materials. At the same time, the introduction of graphene quantum dot-modified silica nanoparticles not only enhances the conductivity of the coating, but also improves the wear resistance and scratch resistance of the coating.

[0137] Through the above four embodiments, the surface treatment process of the anti-fingerprint mobile phone back cover of the present invention shows good adaptability and adjustability. By adjusting the ratio of each component and the processing parameters, a functional coating with excellent anti-fingerprint performance, high transparency, good durability and excellent optical performance can be prepared for mobile phone back covers of different materials and different performance requirements. This flexibility makes the process of the present invention have a wide range of application prospects in actual production.

[0138] Comparative Example 1

[0139] This comparative example provides a surface treatment process for the back cover of an anti-fingerprint mobile phone, wherein the components and preparation method of the spray treatment solution are substantially the same as those of Example 1, but do not contain graphene quantum dot-modified silica nanoparticles. The specific preparation method is as follows:

[0140] First, in a 10L stainless steel reactor, the solvent and dispersant were mixed according to the method of Example 1. Then, only 0.5 parts by weight of R812 hydrophobic nano-silica and 0.4 parts by weight R9200 amino-modified nano-silica was subjected to high shear dispersion. The remaining steps were the same as those in Example 1.

[0141] The surface treatment process steps of the anti-fingerprint mobile phone back cover in this comparative example are the same as those in Example 1, including plasma surface activation treatment, spraying treatment and ultraviolet light curing treatment.

[0142] Through comparative tests, it was found that compared with Example 1, the anti-fingerprint performance and durability of the coating prepared in this comparative example were both reduced. This shows that the graphene quantum dot-modified silica nanoparticles play an important role in the coating, not only enhancing the conductivity of the coating, but also improving the mechanical strength and wear resistance of the coating. This verifies the synergistic effect of the multifunctional nanoparticle composite system in the present invention.

[0143] Comparative Example 2

[0144] This comparative example provides a surface treatment process for anti-fingerprint mobile phone back cover, wherein the components and preparation method of the spray treatment solution are basically the same as those in Example 2, but the fluorinated acrylate mixture is replaced by a single perfluorooctyl ethyl acrylate. The specific preparation method is as follows:

[0145] In a 5L glass reactor, only 3.3 parts by weight of Capstone were used. TM ST-100 perfluorooctyl ethyl acrylate, other steps are the same as Example 2.

[0146] The surface treatment process steps of the anti-fingerprint mobile phone back cover of this comparative example are the same as those of Example 2.

[0147] The test results show that the coating prepared in this comparative example performs poorly in terms of oleophobicity and coating stability compared with Example 2. This demonstrates the importance of using a mixture of fluorinated acrylates of different chain lengths in the present invention, which can form a more stable hydrophobic and oleophobic surface structure and improve the overall performance of the coating.

[0148] Comparative Example 3

[0149] This comparative example provides a surface treatment process for the back cover of an anti-fingerprint mobile phone, wherein the components and preparation method of the spray treatment solution are basically the same as those of Example 3, but plasma surface activation treatment is not performed. The specific preparation method is as follows:

[0150] The preparation method of the spray treatment solution is exactly the same as that of Example 3. However, in the surface treatment process, the plasma surface activation treatment step is omitted, and the spray treatment and UV curing treatment are directly performed.

[0151] The test results show that the coating prepared in this comparative example has significantly lower adhesion and durability compared with Example 3. This fully demonstrates the key role of plasma surface activation treatment in the present invention, which not only cleans the substrate surface, but also generates active groups on the substrate surface, significantly enhancing the bonding force between the coating and the substrate.

[0152] Comparative Example 4

[0153] This comparative example provides a surface treatment process for anti-fingerprint mobile phone back cover, wherein the composition and preparation method of the spray treatment solution are basically the same as those in Example 4, but the crosslinking agent Silquest is not used. TM A-187. The specific preparation method is as follows:

[0154] The spray treatment solution was prepared according to the method of Example 4, but in the additive mixing step, 0.7 parts by weight of Silquest TM Addition of A-187 crosslinker. Other steps remain unchanged.

[0155] The surface treatment process steps of the anti-fingerprint mobile phone back cover of this comparative example are the same as those of Example 4.

[0156] The test results show that the coating prepared in this comparative example has significantly decreased wear resistance, chemical resistance and adhesion compared with Example 4. This verifies the importance of the crosslinking agent in the present invention, which not only enhances the cohesion of the coating, but also improves the interfacial bonding between the coating and the substrate, thereby significantly improving the overall performance and durability of the coating.

[0157] Comparative Example 5

[0158] This comparative example provides a surface treatment process for the back cover of an anti-fingerprint mobile phone, wherein the components and preparation method of the spray treatment solution are substantially the same as those of Example 1, but the ultraviolet light curing treatment is replaced by a thermal curing treatment. The specific preparation method is as follows:

[0159] The preparation method of the spray treatment solution is exactly the same as that of Example 1, except that the photoinitiator The position of 1173 was replaced by an equal amount of thermal initiator dibenzoyl peroxide (BPO).

[0160] The surface treatment process steps of the anti-fingerprint mobile phone back cover of this comparative example include:

[0161] (1) Plasma surface activation treatment: same as in Example 1.

[0162] (2) Spraying treatment: same as in Example 1.

[0163] (3) Thermal curing treatment: Place the sprayed mobile phone back cover in an oven and cure it at 150°C for 30 minutes.

[0164] The test results show that the coating prepared in this comparative example has decreased curing efficiency, coating uniformity and optical properties compared with Example 1. This proves the superiority of the UV curing technology used in the present invention, which not only improves production efficiency, but also improves the overall performance and environmental friendliness of the coating.

[0165] Comparative Example 6

[0166] This comparative example provides a surface treatment process for the back cover of an anti-fingerprint mobile phone, wherein the components and preparation method of the spray treatment solution are basically the same as those in Example 3, but the electrostatic rotary cup spray system is replaced by a traditional air spray system. The specific preparation method is as follows:

[0167] The preparation method of the spray treatment solution is exactly the same as that of Example 3.

[0168] The surface treatment process steps of the anti-fingerprint mobile phone back cover of the comparative example include:

[0169] (1) Plasma surface activation treatment: same as Example 3.

[0170] (2) Spraying treatment: Use the traditional air spray system, spray pressure 0.3MPa, spray gun distance 20cm, spray rate 15g / min.

[0171] (3) UV curing treatment: same as in Example 3.

[0172] The test results show that the coating prepared in this comparative example has obvious disadvantages in thickness uniformity, surface smoothness and coating utilization compared with Example 3. This verifies the importance of the electrostatic rotary cup spraying system used in the present invention, which not only improves the construction quality and uniformity of the coating, but also significantly improves the utilization rate of the coating and reduces environmental pollution.

[0173] Through the above six comparative examples, it can be clearly seen that the invention is innovative and superior in many aspects. First, the synergistic effect of the multifunctional nanoparticle composite system significantly improves the comprehensive performance of the coating. Secondly, the use of a fluorinated acrylate mixture optimizes the hydrophobic and oleophobic properties of the coating. Furthermore, the application of plasma surface activation treatment and ultraviolet light curing technology greatly improves the adhesion and curing efficiency of the coating. Finally, the use of an electrostatic rotary cup spraying system improves the construction quality and environmental friendliness of the coating. These innovative points work together to give the invention significant technical advantages and practical value in the field of anti-fingerprint mobile phone back cover surface treatment.

[0174] In order to comprehensively evaluate the performance of the anti-fingerprint mobile phone back cover surface treatment process of the present invention, the following test experiments were designed:

[0175] 1. Contact angle test

[0176] Experimental conditions: The test was conducted using a contact angle meter at room temperature of 25°C and relative humidity of 50%.

[0177] Experimental method: Use water and oil (n-hexadecane) as test liquids, drop 5 μL of liquid on the surface of the treated mobile phone back cover, and measure the static contact angle. Measure 5 different positions for each sample and take the average value.

[0178] 2. Wear resistance test

[0179] Experimental conditions: Taber wear tester, CS-10 grinding wheel, 500g load.

[0180] Experimental method: After the sample is rotated 1000 times, the weight loss and surface gloss change of the sample are measured.

[0181] 3. Adhesion test

[0182] Experimental conditions: According to ASTM D3359 standard, using the cross scratch method.

[0183] Experimental method: Draw a 10×10 grid on the sample surface, stick it with tape, and then quickly peel it off to observe the peeling of the coating.

[0184] 4. Anti-fingerprint performance test

[0185] Experimental conditions: room temperature 25°C, relative humidity 60%.

[0186] Experimental method: Use an artificial fingerprint simulator to apply 0.5N pressure on the sample surface, hold for 5 seconds and then remove it. Use a microscope to observe the fingerprint residue and use image analysis software to calculate the fingerprint residue area ratio.

[0187] 5. Light transmittance test

[0188] Experimental conditions: Use a spectrophotometer to measure wavelengths in the range of 400-700 nm.

[0189] Experimental method: Place the sample at the sample port of the integrating sphere and measure its transmittance.

[0190] 6. Chemical resistance test

[0191] Experimental conditions: room temperature 25℃.

[0192] Experimental method: The samples were immersed in ethanol, sweat simulation liquid (0.5% sodium chloride, 0.1% urea and 0.1% lactic acid aqueous solution) and oil (olive oil) for 24 hours, the changes in the coating were observed, and the contact angle was retested.

[0193] The test results are as follows:

[0194] Table 1: Contact angle test results of each sample

[0195]

[0196] Table 2: Test results of wear resistance, adhesion and anti-fingerprint performance

[0197]

[0198]

[0199] Table 3: Light transmittance and chemical resistance test results

[0200]

[0201] According to the test results, Example 3 performs best and can be regarded as the best embodiment of the present invention.

[0202] Results analysis and unexpected technical effects

[0203] 1. Super hydrophobic and super oleophobic properties: The embodiments of the present invention all exhibit excellent super hydrophobic and super oleophobic properties, with water contact angles reaching more than 165° and oil contact angles exceeding 145°. This excellent surface performance stems from the synergistic effect of the multifunctional nanoparticle composite system and the fluorinated acrylate mixture. In particular, the introduction of graphene quantum dot-modified silica nanoparticles not only enhances the conductivity of the coating, but also further increases the surface roughness at the nanoscale through its unique flaky structure, thereby achieving a stable Cassie state, which is an unexpected synergistic effect.

[0204] 2. Excellent wear resistance and adhesion: The coatings in the examples show excellent wear resistance and adhesion. This is mainly due to the plasma surface activation treatment and the formation of a multi-component cross-linked network. It is particularly noteworthy that the addition of graphene quantum dots significantly improves the mechanical strength of the coating, which may be due to the two-dimensional structure of graphene forming a nano-enhancement effect in the coating, which is an unexpected discovery.

[0205] 3. Excellent anti-fingerprint performance: The coating in the embodiment shows an extremely low fingerprint residual area ratio, which is not only due to its super hydrophobic and super oleophobic properties, but also closely related to the nanostructure of the coating surface. The multi-scale surface structure reduces the actual contact area between the fingerprint and the surface, while increasing the air barrier. This structural effect of the anti-fingerprint mechanism is an important innovation of the present invention.

[0206] 4. High light transmittance and excellent optical properties: Despite the introduction of a variety of nanoparticles, the coating of the present invention still maintains a high light transmittance of more than 90%. This is mainly due to the uniform dispersion of nanoparticles and the synergistic effect of the multi-component system. In particular, the addition of graphene quantum dots not only does not reduce the light transmittance, but slightly improves the light transmittance of the coating, which may be due to its unique optical properties, such as the quantum confinement effect, which is an unexpected discovery.

[0207] 5. Excellent chemical resistance: The coatings in the examples show excellent chemical resistance, which is mainly due to the synergistic effect of the fluorine-containing component and the multi-component cross-linked network. In particular, in the grease test, Example 3 did not even show any change in the contact angle, which shows that the coating has a strong ability to resist oil stains, which is particularly important for electronic devices used in daily life.

[0208] 6. Innovation in preparation process: The electrostatic rotary cup spraying system and LED-UV curing technology used in the present invention not only improve the quality and uniformity of the coating, but also significantly improve production efficiency and environmental friendliness. In particular, the combination of this process and the multi-component system achieves rapid curing while ensuring the formation of complex nanostructures. The synergistic effect of this process and the formula is another important innovation of the present invention.

[0209] In summary, the present invention realizes a mobile phone back cover surface treatment process with super hydrophobic and super oleophobic, high wear resistance, strong adhesion, excellent anti-fingerprint performance, high transmittance and excellent chemical resistance through the synergistic effect of multifunctional nanoparticle composite system, fluorinated acrylate mixture, plasma surface activation treatment and advanced spray curing process. This synergistic improvement of multiple performances, especially the realization of super hydrophobic and super oleophobic performance while maintaining high transmittance, is unpredictable for those skilled in the art. In addition, the unexpected effect of graphene quantum dots in enhancing the mechanical and optical properties of coatings provides a new research direction for the development of future functional coatings.

[0210] 7. Weather resistance test

[0211] Experimental conditions: Use a xenon arc lamp aging test chamber and test according to ASTM G155 standard.

[0212] Experimental method: Samples were exposed to simulated sunlight, temperature and humidity cycles for 1000 hours. Contact angle, light transmittance and color change were measured every 200 hours.

[0213] 8. Antibacterial performance test

[0214] Experimental conditions: Tested in accordance with JIS Z 2801 standard.

[0215] Experimental method: Add the culture solution of Escherichia coli and Staphylococcus aureus on the surface of the sample, and count the number of bacteria after culturing at 35℃ for 24 hours.

[0216] 9. Thermal stability test

[0217] Experimental conditions: A thermogravimetric analyzer (TGA) was used.

[0218] Experimental method: In a nitrogen atmosphere, the sample was heated from room temperature to 600°C at a heating rate of 10°C / min, and the weight loss of the sample was recorded.

[0219] 10. Electrical performance test

[0220] Experimental conditions: The surface resistance was measured using the four-probe method.

[0221] Experimental method: Select 5 points evenly on the sample surface for measurement and take the average value.

[0222] 11. Haze test

[0223] Experimental conditions: Use a haze meter and test according to ASTM D1003 standard.

[0224] Experimental method: Measure the total light transmittance and diffuse reflectance transmittance of the sample and calculate the haze value.

[0225] 12. Impact resistance test

[0226] Experimental conditions: The test was conducted using a falling ball impact tester in accordance with ASTM D2794.

[0227] Experimental method: Drop a 500g steel ball from different heights and observe the damage to the coating.

[0228] Test results:

[0229] Table 4: Weathering test results

[0230]

[0231]

[0232] Table 5: Antibacterial performance and thermal stability test results

[0233]

[0234] Table 6: Electrical properties, haze and impact resistance test results

[0235]

[0236] Result analysis and new technical effects:

[0237] 1. Excellent weather resistance: After 1000 hours of accelerated aging test, the contact angle of Example 3 decreased by only 2.5%, the transmittance decreased by only 0.8%, and the color change was only 0.5ΔE. This shows that the coating of the present invention has excellent long-term stability and can maintain its function in various harsh environments. This improvement in weather resistance may be due to the dense network structure formed by the multi-component system and the absorption and scattering of UV light by graphene quantum dots, which is an unexpected discovery.

[0238] 2. Significant antibacterial performance: Example 3 has an antibacterial rate of 99.8% and 99.5% against Escherichia coli and Staphylococcus aureus, respectively. This highly efficient antibacterial performance may be due to the synergistic effect of nano-silica and graphene quantum dots. In particular, graphene quantum dots may destroy bacterial cell membranes through a dual mechanism of physical penetration and chemical oxidation, which is an unexpected function.

[0239] 3. Excellent thermal stability: The thermal decomposition temperature of Example 3 reaches 398°C, which is much higher than that of the comparative example. This high thermal stability is not only due to the heat resistance of the fluorine-containing component, but also due to the fact that the graphene quantum dots form a protective layer at high temperatures, preventing further decomposition of the coating. This improvement in thermal stability is of great significance to the safety and durability of electronic devices.

[0240] 4. Improved electrical properties: The surface resistance of Example 3 is 7.0×10^8Ω / sq, which is two orders of magnitude lower than that of the comparative example. This improvement in conductivity is mainly attributed to the introduction of graphene quantum dots. It is worth noting that this moderate conductivity not only helps to prevent static electricity, but also may suppress electromagnetic interference to a certain extent, which is of great significance for the performance optimization of modern electronic devices.

[0241] 5. Extremely low haze: The haze of Example 3 is only 0.5%, which is much lower than that of the comparative example. This combination of low haze and high light transmittance proves that the present invention achieves excellent optical performance while maintaining excellent functionality. This may be due to the uniform dispersion of nanoparticles and the synergistic effect of the multi-component system, which forms a special optical structure.

[0242] 6. Excellent impact resistance: The impact resistance height of Example 3 reaches 100 cm, which is much higher than that of the comparative example. This improvement in mechanical strength may be due to the formation of a multi-component cross-linked network and the strengthening effect of graphene quantum dots. In particular, graphene quantum dots may form a nanoscale "shock-absorbing" structure in the coating, which is an unexpected discovery.

[0243] In summary, these additional test results further confirm the versatility and excellent performance of the present invention. In particular, the synergistic improvement in weather resistance, antibacterial properties, thermal stability, electrical properties, optical properties and mechanical strength demonstrates a major breakthrough in the field of materials science and surface engineering. This synergistic improvement in multiple properties, especially the unexpected effects of graphene quantum dots in antibacterial, conductive and mechanical enhancement, opens up new research directions for the design and application of functional coatings, and also provides innovative ideas for the development of surface treatment technology for smart electronic devices.

[0244] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A surface treatment process for anti-fingerprint mobile phone back cover, characterized in that: The following steps are involved: (1) Plasma surface activation treatment: The back cover of the mobile phone is subjected to plasma surface activation treatment using a mixture of argon, oxygen and carbon tetrafluoride; (2) Spraying treatment: spraying the spraying treatment solution onto the back cover of the mobile phone that has been subjected to plasma surface activation treatment; (3) UV curing treatment: UV curing treatment is performed on the back cover of the mobile phone after spraying; Wherein, the spray treatment solution comprises the following components: a) 1.5-5.5 parts by weight of a fluorinated acrylate mixture; b) 1.2-3.5 parts by weight of a modified silica nanoparticle mixture; c) 10-12 parts by weight of an organic solvent mixture; d) 0.3-0.6 parts by weight of a dispersant; e) 0.2-0.4 parts by weight of a leveling agent; f) 0.4-0.8 parts by weight of a cross-linking agent; g) 0.3-0.6 parts by weight of a photoinitiator.

2. The anti-fingerprint mobile phone back cover surface treatment process according to claim 1 is characterized in that: The fluorinated acrylate mixture comprises: 0.6-2.4 parts by weight of perfluorooctyl ethyl acrylate, 0.5-1.8 parts by weight of 1H,1H,2H,2H-perfluorodecyl acrylate and 0.4-1.3 parts by weight of methyl trifluoroethyl acrylate.

3. The anti-fingerprint mobile phone back cover surface treatment process according to claim 1, characterized in that: The modified silica nanoparticle mixture comprises: 0.5-1.5 parts by weight of hydrophobic nano-silica, 0.4-1.2 parts by weight of amino-modified nano-silica and 0.3-0.8 parts by weight of graphene quantum dot-modified silica nanoparticles.

4. The anti-fingerprint mobile phone back cover surface treatment process according to claim 1, characterized in that: The organic solvent mixture comprises: 3.5-4.5 parts by weight of ethanol, 2.5-3.5 parts by weight of isopropanol, 2-2.5 parts by weight of cyclohexanone and 2-2.5 parts by weight of propylene glycol methyl ether acetate.

5. The anti-fingerprint mobile phone back cover surface treatment process according to claim 1, characterized in that: The method for preparing the spray treatment solution comprises the following steps: (1) First, an organic solvent and a dispersant are mixed in a reactor; (2) Secondly, hydrophobic nano-silica, amino-modified nano-silica and graphene quantum dot-modified silica nanoparticles are added in sequence for high shear dispersion; (3) Then, mixing the fluorinated acrylate and a portion of the organic solvent in another reactor; (4) again, adding the fluorinated acrylate mixture into the nanoparticle dispersion; (5) Then, add a leveling agent, a crosslinking agent and a photoinitiator in sequence; (6) Finally, the mixture is homogenized, filtered, and degassed.

6. The anti-fingerprint mobile phone back cover surface treatment process according to claim 1, characterized in that: The process parameters of the plasma surface activation treatment are: Air pressure 18-22Pa, DC voltage 26-29V, RF power frequency 50-70Hz, processing time 70-100 seconds, substrate temperature 30-35℃.

7. The anti-fingerprint mobile phone back cover surface treatment process according to claim 1, characterized in that: The spraying process adopts an electrostatic rotary cup spraying system, and its process parameters are: The diameter of the rotary cup is 50-60mm, the rotation speed of the rotary cup is 35000-45000rpm, the spraying voltage is 60-80kV, the spraying distance is 15-18cm, the spraying rate is 16-19g / min, the substrate temperature is 24-28℃, the relative humidity of the environment is 45-55%, and the laminar wind speed is 0.3-0.5m / s.

8. The anti-fingerprint mobile phone back cover surface treatment process according to claim 1, characterized in that: The UV curing process uses LED-UV lamp, and its process parameters are: Main wavelength 365nm, auxiliary wavelength 385nm and 395nm, power density 600-800mW / cm 2 , irradiation distance 8-10cm, curing time 20-25 seconds, curing environment temperature 28-33℃, nitrogen protection flow rate 3-4L / min, oxygen concentration controlled at 50-100ppm.

9. The surface treatment process for anti-fingerprint mobile phone back cover according to any one of claims 1 to 8, characterized in that: The material of the mobile phone back cover is selected from magnesium alloy, aluminum alloy or titanium alloy.

10. A mobile phone back cover prepared by the anti-fingerprint mobile phone back cover surface treatment process according to any one of claims 1 to 9, characterized in that: The surface of the mobile phone back cover is provided with a hydrophobic and oleophobic coating with a microscopic rough structure.

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