Wear-resistant and anti-fingerprint coating and preparation method thereof

Abstract

The invention discloses a wear-resistant and anti-fingerprint coating and a preparation method thereof, relating to the technical field of coatings. The preparation method comprises the following steps: adding a composite lignin lubricant to anhydrous ethanol and stirring evenly to obtain a lignin stock solution; adding a modified cellulose nanocrystal suspension to the lignin stock solution under stirring, and vacuum distilling to obtain a lignin-cellulose composite filler; adding lignin to N,N-dimethylformamide and stirring evenly, adding hexamethylene diisocyanate and dibutyltin dilaurate, heating to 90-95°C for reaction for 3-3.5h, adding polycarbonate polyol, and keeping the temperature for reaction for 6-6.5h to obtain a lignin-modified polyurethane; and adding the lignin-cellulose composite filler to the lignin-modified polyurethane and stirring evenly to obtain the wear-resistant and anti-fingerprint coating.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to a wear-resistant and anti-fingerprint coating and a preparation method thereof. Background Art

[0002] In today's coating application field, with the continuous advancement of science and technology and the improvement of people's quality of life, the requirements for coating performance are becoming more diversified and high-end, especially in terms of wear resistance and anti-fingerprint.

[0003] In the field of electronic devices such as mobile phones, tablets, and smart watches, their casings and screens frequently come into contact with users' fingers. Fingerprint residue not only affects the product's aesthetics but also reduces screen clarity and touch sensitivity, severely impacting the user experience. Furthermore, during daily use, the device surface is constantly subjected to various frictions, such as friction with the tabletop and clothing, which can easily cause coating wear, resulting in scratches and paint peeling on the device's exterior. This not only shortens the product's lifespan but also increases replacement costs for consumers.

[0004] In the automotive interior sector, components such as dashboards, steering wheels, and door trims are often stained with fingerprints, affecting the overall aesthetics and cleanliness of the vehicle interior. Furthermore, while the vehicle is in motion, interior components are subject to mechanical stress due to vibration and friction, requiring coatings with excellent wear resistance to maintain the texture and quality of the interior.

[0005] At present, some wear-resistant coatings available on the market can resist friction to a certain extent, but their anti-fingerprint effect is poor; and the wear resistance of some anti-fingerprint coatings is difficult to meet the actual use requirements. Traditional coating preparation technologies mostly use simple physical mixing or single chemical modification to achieve certain performance improvements, which has many limitations. For example, during the preparation process, the interface compatibility between the filler and the matrix is ​​poor, resulting in unstable overall performance of the coating. When subjected to external forces, the filler easily falls off from the matrix, thereby reducing the wear resistance. Moreover, traditional coatings are difficult to take into account the synergistic optimization of multiple properties and cannot meet the high-performance and multifunctional requirements of modern industry and life for coatings.

[0006] Against this backdrop, developing a coating with both excellent wear resistance and high anti-fingerprint properties, and its preparation method, has become an important and pressing issue in the field of coatings technology. This present invention addresses this need, aiming to overcome the shortcomings of existing technologies and provide a wear-resistant, anti-fingerprint coating with improved overall performance and its preparation method. Summary of the Invention

[0007] The purpose of the present invention is to provide a wear-resistant and anti-fingerprint coating and a preparation method thereof, so as to solve the problems raised in the prior art.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A method for preparing a wear-resistant and anti-fingerprint coating comprises the following steps: S1: adding a composite lignin lubricant to anhydrous ethanol and stirring evenly to obtain a lignin stock solution; while stirring, adding a modified cellulose nanocrystal suspension to the lignin stock solution and performing vacuum distillation to obtain a lignin-cellulose composite filler;

[0010] S2: adding lignin to N,N-dimethylformamide and stirring evenly, adding hexamethylene diisocyanate and dibutyltin dilaurate, heating to 90-95°C for reaction for 3-3.5 hours, adding polycarbonate polyol, and keeping the temperature for reaction for 6-6.5 hours to obtain lignin-modified polyurethane; adding lignin-cellulose composite filler to the lignin-modified polyurethane and stirring evenly to obtain a wear-resistant and anti-fingerprint coating;

[0011] Furthermore, the composite lignin lubricant is prepared from benzotriazole, tetrabutylphosphine hydroxide and wood; and the modified cellulose nanocrystals are prepared from oxidized cellulose nanocrystals and octadecylamine.

[0012] Furthermore, the preparation process of the modified cellulose nanocrystal suspension includes the following steps: adding oxidized cellulose nanocrystals to deionized water, ultrasonically dispersing, adding 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, stirring for 30-45 minutes, adding N-hydroxysuccinimide, shaking at room temperature for 1-1.5 hours, adding octadecylamine, ultrasonically treating for 2-2.5 hours, stirring for reaction for 2-2.5 hours, and washing the suspension with 0.1M hydrochloric acid solution and anhydrous ethanol by centrifugation to obtain a modified cellulose nanocrystal suspension.

[0013] Furthermore, during the preparation of the modified cellulose nanocrystal suspension, the molar ratio of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide:N-hydroxysuccinimide:octadecylamine is 1:1:1.

[0014] Furthermore, the preparation process of the oxidized cellulose nanocrystals comprises the following steps: Step (1): degumming sisal fibers to obtain degummed sisal fibers;

[0015] Step (2): treating the degummed sisal fiber with alkali to obtain alkali-treated sisal fiber;

[0016] Step (3): adding alkali-treated sisal fiber to deionized water, ultrasonically dispersing, adding sodium bromide and 2,2,6,6-tetramethylpiperidinium oxide, stirring at room temperature for 30-45 minutes, adding 12 wt% sodium hypochlorite aqueous solution under stirring, using a pH meter to detect the reaction system, and maintaining the pH of the reaction system at 10-10.5 by adding 1 wt% sodium hydroxide aqueous solution. When the reaction no longer consumes sodium hydroxide, adding anhydrous ethanol to terminate the reaction, centrifuging, collecting the precipitate, washing with deionized water until neutral, adding the precipitate to deionized water, ultrasonically treating, collecting the supernatant, centrifuging, collecting the precipitate, and freeze-drying to obtain oxidized cellulose nanocrystals.

[0017] Furthermore, in the preparation process of the oxidized cellulose nanocrystals, the mass ratio of alkali-treated sisal fiber: sodium bromide: 2,2,6,6-tetramethylpiperidinyl oxide is 1:0.2:0.02.

[0018] Furthermore, the preparation method of the composite lignin lubricant includes the following steps: adding benzotriazole and tetrabutylphosphine hydroxide into a reaction vessel, reacting at room temperature for 8-9 hours, extracting the aqueous phase, vacuum distilling, adding anhydrous magnesium sulfate to dry the organic phase, filtering to obtain an ionic liquid; heating the ionic liquid to 90-95°C, adding lignin, and stirring evenly to obtain a composite lignin lubricant.

[0019] Furthermore, during the preparation of the composite lignin lubricant, the molar ratio of benzotriazole to tetrabutylphosphonium hydroxide is 1:1, and the amount of lignin added is 1-5 wt% of the mass of the ionic liquid.

[0020] Furthermore, during the preparation of the lignin-cellulose composite filler, the concentration of the lignin stock solution was 8 mg / mL, the concentration of the modified cellulose nanocrystal suspension was 4-16 mg / mL, and the volume ratio of the modified cellulose nanocrystal suspension to the lignin stock solution was 7:3.

[0021] Furthermore, in the preparation process of the lignin-modified polyurethane, the proportions of each component, calculated by mass, include: 4-6.3 parts of hexamethylene diisocyanate, 0.01-0.02 parts of dibutyltin dilaurate, 1.4-16.1 parts of polycarbonate polyol, and 1-2 parts of lignin; in the preparation process of the wear-resistant and anti-fingerprint coating, the mass ratio of lignin-cellulose composite filler: lignin-modified polyurethane is 3:(2-4).

[0022] Furthermore, the sisal fiber degumming treatment includes the following steps: adding the sisal fiber to a 3wt% sodium hydroxide solution containing 2wt% sodium silicate, heating it to 90-95°C and soaking it for 3-3.5h, washing the fiber with deionized water until it is neutral, vacuum drying, adding the fiber to a 3wt% ethylenediaminetetraacetic acid solution; the material-liquid ratio is 1:40, heating it to 30-35°C and reacting it for 1-1.5h, washing the fiber with deionized water until it is neutral, vacuum drying, adding the fiber to a mixed solution of 20g / L sodium hydroxide and 22.5mL / L hydrogen peroxide, heating it to 95-96°C and reacting it for 3.5-4h, the material-liquid ratio is 1:50, washing, and vacuum drying to obtain degummed sisal fiber.

[0023] Furthermore, the alkali treatment of the degummed sisal fiber includes the following steps: grinding the degummed sisal fiber and adding it to a 15% sodium hydroxide solution, heating it to 60-65°C for reaction for 4-4.5 hours, with a material-liquid ratio of 1:50, washing, and drying; placing the fiber in a dimethyl sulfoxide solution, heating it to 70-75°C for reaction for 3-3.5 hours, with a material-liquid ratio of 1:20, washing, and drying to obtain alkali-treated sisal fiber.

[0024] Furthermore, the preparation method of lignin includes the following steps: adding poplar sawdust to ethanol water solution, stirring evenly, adding 2wt% sulfuric acid solution, heating to 180-185°C for reaction for 2-2.5h, cooling to room temperature, filtering, vacuum concentrating, adding water for precipitation and separation, and vacuum drying to obtain lignin.

[0025] Furthermore, in the preparation process of the lignin, the volume ratio of ethanol to water in the ethanol-water solution is 7:3.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention introduces long-chain alkyl groups onto the surface of cellulose nanocrystals through TEMPO oxidation and octadecylamine amidation to enhance interfacial compatibility with the hydrophobic polyurethane matrix. The resulting modified cellulose nanocrystals significantly improve the mechanical strength and hardness of the resulting coating. The high specific surface area and rigid structure of the modified cellulose nanocrystals form a reinforced network within the polyurethane matrix, effectively dispersing external stress and reducing wear during friction. The ionic liquid formed by the benzotriazole and tetrabutylphosphonium hydroxide in the composite lignin lubricant forms a lubricating layer on the coating surface, reducing the coefficient of friction, further minimizing wear, and enhancing the coating's wear resistance.

[0028] 2. The present invention prepares a lignin-cellulose composite filler by co-assembling modified cellulose nanocrystals and a composite lignin lubricant. The surface of the cellulose nanocrystals modified with octadecylamine forms a hydrophobic layer to reduce the adhesion of grease and moisture in fingerprints. The nano-scale rough surface of the composite filler repels pollutants through the "lotus effect", realizes a self-cleaning function, and achieves high-efficiency anti-fingerprint performance.

[0029] 3. This invention further improves the dispersion of lignin-cellulose composite fillers in lignin-modified polyurethane by modifying it with lignin. This lignin-modified polyurethane, prepared by reacting lignin's hydroxyl groups with isocyanate, differs from traditional physical blending of lignin and polyurethane in that it features a denser cross-linked network at the top layer, resulting in a coating with excellent wear resistance and anti-fingerprint properties. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] In the following examples, the specification of polycarbonate polyol is: Mn=2000; the specification of polyurethane is: Mn=2000; and the remaining raw materials are commercially available.

[0032] The preparation method of oxidized cellulose nanocrystals comprises the following steps: step (1): adding 2g of sisal fiber to a 3wt% sodium hydroxide solution containing 2wt% sodium silicate, heating to 90°C and soaking for 3h, washing the fiber with deionized water until neutral, vacuum drying, adding the fiber to a 3wt% ethylenediaminetetraacetic acid solution with a material-liquid ratio of 1:40, heating to 30-35°C and reacting for 1h, washing the fiber with deionized water until neutral, vacuum drying, adding the fiber to a mixed solution of 20g / L sodium hydroxide and 22.5mL / L hydrogen peroxide, heating to 95-96°C and reacting for 3.5h, with a material-liquid ratio of 1:50, washing, and vacuum drying to obtain degummed sisal fiber.

[0033] Step (2): Grind the degummed sisal fiber and add it to a 15% sodium hydroxide solution, heat it to 60°C and react for 4 hours, with a material-liquid ratio of 1:50, wash it, and dry it. Then, add the fiber to a dimethyl sulfoxide solution, heat it to 70°C and react for 3 hours, with a material-liquid ratio of 1:20, wash it, and dry it to obtain an alkali-treated sisal fiber.

[0034] Step (3): 1 g of alkali-treated sisal fiber was added to deionized water, ultrasonically dispersed, 0.2 g of sodium bromide and 0.02 g of 2,2,6,6-tetramethylpiperidinyl oxide were added, and stirred at room temperature for 30 min. A 12 wt% sodium hypochlorite aqueous solution was added under stirring, and the reaction system was detected using a pH meter. The pH of the reaction system was maintained at 10 by adding a 1 wt% sodium hydroxide aqueous solution. When the reaction no longer consumed sodium hydroxide, anhydrous ethanol was added to terminate the reaction, centrifuged, and the precipitate was collected. The precipitate was washed with deionized water until neutral, and the precipitate was added to deionized water, ultrasonically treated, and the supernatant was collected. The precipitate was centrifuged and collected, and freeze-dried to obtain oxidized cellulose nanocrystals.

[0035] The preparation method of lignin comprises the following steps: adding 2 g of poplar sawdust to an ethanol-water solution (ethanol:water volume ratio is 7:3), stirring evenly, adding 2 wt% sulfuric acid solution, heating to 180° C. for reaction for 2 h, cooling to room temperature, filtering, vacuum concentrating, adding water for precipitation and separation, and vacuum drying to obtain lignin.

[0036] Example 1: A method for preparing a wear-resistant and anti-fingerprint coating, comprising the following steps: S1: adding 1 mol of benzotriazole and 1 mol of tetrabutylphosphonium hydroxide to a reaction vessel, reacting at room temperature for 8 hours, extracting the aqueous phase, vacuum distilling, adding anhydrous magnesium sulfate to dry the organic phase, and filtering to obtain an ionic liquid; heating the ionic liquid to 90° C., adding 1 wt % of lignin, and stirring uniformly to obtain a composite lignin lubricant;

[0037] S2: Add oxidized cellulose nanocrystals to deionized water, disperse by ultrasonication, add 1 mol of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, stir for 30 min, add 1 mol of N-hydroxysuccinimide, shake at room temperature for 1 h, add 1 mol of octadecylamine, ultrasonicate for 2 h, stir and react for 2 h, and wash the suspension with 0.1 M hydrochloric acid solution and anhydrous ethanol by centrifugation to obtain a modified cellulose nanocrystal suspension;

[0038] S3: Add the composite lignin lubricant to anhydrous ethanol and stir evenly to obtain an 8 mg / mL lignin stock solution; while stirring, add a 4 mg / mL modified cellulose nanocrystal suspension to the lignin stock solution and vacuum distill to obtain a lignin-cellulose composite filler; wherein the volume ratio of the modified cellulose nanocrystal suspension to the lignin stock solution is 7:3;

[0039] S4: Add 1 part of lignin to N,N-dimethylformamide, stir evenly, add 6.3 parts of hexamethylene diisocyanate and 0.01 parts of dibutyltin dilaurate, heat to 90°C and react for 3 hours, add 16.1 parts of polycarbonate polyol, keep warm and react for 6 hours to obtain lignin-modified polyurethane; add 3g of lignin-cellulose composite filler to 4g of lignin-modified polyurethane, stir evenly to obtain a wear-resistant and anti-fingerprint coating.

[0040] Example 2: A method for preparing a wear-resistant and anti-fingerprint coating, comprising the following steps: S1: adding 1 mol of benzotriazole and 1 mol of tetrabutylphosphine hydroxide to a reaction vessel, reacting at room temperature for 8 hours, extracting the aqueous phase, vacuum distilling, adding anhydrous magnesium sulfate to dry the organic phase, and filtering to obtain an ionic liquid; heating the ionic liquid to 90° C., adding 3 wt % of lignin, and stirring uniformly to obtain a composite lignin lubricant;

[0041] S2: Add oxidized cellulose nanocrystals to deionized water, disperse by ultrasonication, add 1 mol of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, stir for 30 min, add 1 mol of N-hydroxysuccinimide, shake at room temperature for 1 h, add 1 mol of octadecylamine, ultrasonicate for 2 h, stir and react for 2 h, and wash the suspension with 0.1 M hydrochloric acid solution and anhydrous ethanol by centrifugation to obtain a modified cellulose nanocrystal suspension;

[0042] S3: Add the composite lignin lubricant to anhydrous ethanol and stir evenly to obtain an 8 mg / mL lignin stock solution; while stirring, add an 8 mg / mL modified cellulose nanocrystal suspension to the lignin stock solution and vacuum distill to obtain a lignin-cellulose composite filler; wherein the volume ratio of the modified cellulose nanocrystal suspension to the lignin stock solution is 7:3;

[0043] S4: Add 1 part of lignin to N,N-dimethylformamide, stir evenly, add 5.7 parts of hexamethylene diisocyanate and 0.01 parts of dibutyltin dilaurate, heat to 90°C and react for 3 hours, add 13.2 parts of polycarbonate polyol, keep warm and react for 6 hours to obtain lignin-modified polyurethane; add 3g of lignin-cellulose composite filler to 4g of lignin-modified polyurethane, stir evenly to obtain a wear-resistant and anti-fingerprint coating.

[0044] Example 3: A method for preparing a wear-resistant and anti-fingerprint coating, comprising the following steps: S1: adding 1 mol of benzotriazole and 1 mol of tetrabutylphosphine hydroxide to a reaction vessel, reacting at room temperature for 8 hours, extracting the aqueous phase, vacuum distilling, adding anhydrous magnesium sulfate to dry the organic phase, and filtering to obtain an ionic liquid; heating the ionic liquid to 90° C., adding 5 wt % of lignin, and stirring uniformly to obtain a composite lignin lubricant;

[0045] S2: Add oxidized cellulose nanocrystals to deionized water, disperse by ultrasonication, add 1 mol of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, stir for 30 min, add 1 mol of N-hydroxysuccinimide, shake at room temperature for 1 h, add 1 mol of octadecylamine, ultrasonicate for 2 h, stir and react for 2 h, and wash the suspension with 0.1 M hydrochloric acid solution and anhydrous ethanol by centrifugation to obtain a modified cellulose nanocrystal suspension;

[0046] S3: Add the composite lignin lubricant to anhydrous ethanol and stir evenly to obtain an 8 mg / mL lignin stock solution; while stirring, add an 8 mg / mL modified cellulose nanocrystal suspension to the lignin stock solution and vacuum distill to obtain a lignin-cellulose composite filler; wherein the volume ratio of the modified cellulose nanocrystal suspension to the lignin stock solution is 7:3;

[0047] S4: Add 1 part of lignin to N,N-dimethylformamide, stir evenly, add 4.6 parts of hexamethylene diisocyanate and 0.01 parts of dibutyltin dilaurate, heat to 90°C and react for 3 hours, add 4.3 parts of polycarbonate polyol, keep warm and react for 6 hours to obtain lignin-modified polyurethane; add 3g of lignin-cellulose composite filler to 4g of lignin-modified polyurethane, stir evenly to obtain a wear-resistant and anti-fingerprint coating.

[0048] Example 4: A method for preparing a wear-resistant and anti-fingerprint coating, comprising the following steps: S1: adding 1 mol of benzotriazole and 1 mol of tetrabutylphosphine hydroxide to a reaction vessel, reacting at room temperature for 8 hours, extracting the aqueous phase, vacuum distilling, adding anhydrous magnesium sulfate to dry the organic phase, and filtering to obtain an ionic liquid; heating the ionic liquid to 90° C., adding 5 wt % of lignin, and stirring uniformly to obtain a composite lignin lubricant;

[0049] S2: Add oxidized cellulose nanocrystals to deionized water, disperse by ultrasonication, add 1 mol of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, stir for 30 min, add 1 mol of N-hydroxysuccinimide, shake at room temperature for 1 h, add 1 mol of octadecylamine, ultrasonicate for 2 h, stir and react for 2 h, and wash the suspension with 0.1 M hydrochloric acid solution and anhydrous ethanol by centrifugation to obtain a modified cellulose nanocrystal suspension;

[0050] S3: Add the composite lignin lubricant to anhydrous ethanol and stir evenly to obtain an 8 mg / mL lignin stock solution; while stirring, add 16 mg / mL modified cellulose nanocrystal suspension to the lignin stock solution and vacuum distill to obtain a lignin-cellulose composite filler; wherein the volume ratio of the modified cellulose nanocrystal suspension to the lignin stock solution is 7:3;

[0051] S4: Add 1 part of lignin to N,N-dimethylformamide, stir evenly, add 1.4 parts of hexamethylene diisocyanate and 0.01 parts of dibutyltin dilaurate, heat to 90°C and react for 3 hours, add 4.2 parts of polycarbonate polyol, keep warm and react for 6 hours to obtain lignin-modified polyurethane; add 3g of lignin-cellulose composite filler to 2g of lignin-modified polyurethane, stir evenly to obtain a wear-resistant and anti-fingerprint coating.

[0052] Comparative Example 1: A method for preparing a wear-resistant and anti-fingerprint coating, comprising the following steps: S1: adding oxidized cellulose nanocrystals to deionized water, ultrasonically dispersing the mixture, adding 1 mol of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, stirring for 30 minutes, adding 1 mol of N-hydroxysuccinimide, shaking the mixture at room temperature for 1 hour, adding 1 mol of octadecylamine, ultrasonically treating the mixture for 2 hours, stirring the mixture for 2 hours, and washing the suspension with 0.1 M hydrochloric acid solution and anhydrous ethanol by centrifugation to obtain a modified cellulose nanocrystal suspension;

[0053] S2: Add 1 part of lignin to N,N-dimethylformamide, stir evenly, add 6.3 parts of hexamethylene diisocyanate and 0.01 parts of dibutyltin dilaurate, heat to 90°C and react for 3 hours, add 16.1 parts of polycarbonate polyol, keep warm and react for 6 hours to obtain lignin-modified polyurethane; add 3g of modified cellulose nanocrystal suspension to 4g of lignin-modified polyurethane, stir evenly to obtain a wear-resistant and anti-fingerprint coating.

[0054] Comparative Example 2: A method for preparing a wear-resistant and anti-fingerprint coating, comprising the following steps: S1: adding 1 mol of benzotriazole and 1 mol of tetrabutylphosphine hydroxide to a reaction vessel, reacting at room temperature for 8 hours, extracting the aqueous phase, vacuum distilling, adding anhydrous magnesium sulfate to dry the organic phase, and filtering to obtain an ionic liquid; heating the ionic liquid to 90° C., adding 1 wt % of lignin, and stirring uniformly to obtain a composite lignin lubricant;

[0055] S2: Add the composite lignin lubricant to anhydrous ethanol and stir evenly to obtain an 8 mg / mL lignin stock solution; while stirring, add a 4 mg / mL aqueous suspension of oxidized cellulose nanocrystals to the lignin stock solution and vacuum distill to obtain a lignin-cellulose composite filler; wherein the volume ratio of the aqueous suspension of oxidized cellulose nanocrystals to the lignin stock solution is 7:3;

[0056] S3: Add 1 part of lignin to N,N-dimethylformamide, stir evenly, add 6.3 parts of hexamethylene diisocyanate and 0.01 parts of dibutyltin dilaurate, heat to 90°C and react for 3 hours, add 16.1 parts of polycarbonate polyol, keep warm and react for 6 hours to obtain lignin-modified polyurethane; add 3g of lignin-cellulose composite filler to 4g of lignin-modified polyurethane, stir evenly to obtain a wear-resistant and anti-fingerprint coating.

[0057] Comparative Example 3: A method for preparing a wear-resistant and anti-fingerprint coating, comprising the following steps: S1: adding 1 mol of benzotriazole and 1 mol of tetrabutylphosphine hydroxide to a reaction vessel, reacting at room temperature for 8 hours, extracting the aqueous phase, vacuum distilling, adding anhydrous magnesium sulfate to dry the organic phase, and filtering to obtain an ionic liquid; heating the ionic liquid to 90° C., adding 1 wt % of lignin, and stirring uniformly to obtain a composite lignin lubricant;

[0058] S2: Add oxidized cellulose nanocrystals to deionized water, disperse by ultrasonication, add 1 mol of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, stir for 30 min, add 1 mol of N-hydroxysuccinimide, shake at room temperature for 1 h, add 1 mol of octadecylamine, ultrasonicate for 2 h, stir and react for 2 h, and wash the suspension with 0.1 M hydrochloric acid solution and anhydrous ethanol by centrifugation to obtain a modified cellulose nanocrystal suspension;

[0059] S3: Add the composite lignin lubricant to anhydrous ethanol and stir evenly to obtain an 8 mg / mL lignin stock solution; while stirring, add a 4 mg / mL modified cellulose nanocrystal suspension to the lignin stock solution and vacuum distill to obtain a lignin-cellulose composite filler; wherein the volume ratio of the modified cellulose nanocrystal suspension to the lignin stock solution is 7:3;

[0060] S4: Add 1 part of lignin to 4 g of polyurethane and stir evenly to obtain lignin-modified polyurethane; add 3 g of lignin-cellulose composite filler to 4 g of lignin-modified polyurethane and stir evenly to obtain a wear-resistant and anti-fingerprint coating.

[0061] Experiment: The wear-resistant and anti-fingerprint coatings prepared in the above examples and comparative examples were spin-coated on the surface of a 304 stainless steel plate with a coating thickness of 20 μm. After drying and curing, the coatings were tested.

[0062] Anti-fingerprint performance test: Press the coating surface with a fingerprint for 5 seconds to simulate fingerprint contamination. Sprinkle excess zinc oxide powder to cover the surface, gently brush to remove excess powder, observe the distribution of residual powder under a microscope, and quantify the fingerprint area ratio.

[0063] Wear resistance testing: A diamond-shaped indenter was used to scratch the coating surface at a load of 50N. The cross-section of the wear track was scanned and the volume loss was calculated. The friction coefficient was tested using a friction and wear testing machine at a load of 2N, a frequency of 2Hz, and a friction time of 20min. The magic ball was a φ6mm tungsten carbide ball.

[0064] The experimental results are shown in Table 1 below.

[0065] Table 1 Wear-resistant and anti-fingerprint coating performance test data

[0066]

[0067] Conclusion: The wear-resistant and anti-fingerprint coating prepared by the present invention has excellent anti-fingerprint and wear resistance.

[0068] In Comparative Example 1, no composite lignin lubricant was added, resulting in reduced anti-fingerprint performance and wear resistance.

[0069] In Comparative Example 2, oxidized cellulose nanocrystals were used, resulting in reduced anti-fingerprint performance and wear resistance.

[0070] In Comparative Example 3, lignin was used to physically blend and modify the polyurethane, resulting in reduced anti-fingerprint performance and wear resistance.

[0071] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A method for preparing a wear-resistant and anti-fingerprint coating, characterized in that: The following steps are involved: S1: adding the composite lignin lubricant to anhydrous ethanol and stirring evenly to obtain a lignin stock solution; while stirring, adding the modified cellulose nanocrystal suspension to the lignin stock solution and vacuum distilling to obtain a lignin-cellulose composite filler; S2: adding lignin to N,N-dimethylformamide and stirring evenly, adding hexamethylene diisocyanate and dibutyltin dilaurate, heating to 90-95°C for reaction for 3-3.5 hours, adding polycarbonate polyol, and keeping the temperature for reaction for 6-6.5 hours to obtain lignin-modified polyurethane; adding lignin-cellulose composite filler to the lignin-modified polyurethane and stirring evenly to obtain a wear-resistant and anti-fingerprint coating; The preparation process of the modified cellulose nanocrystal suspension comprises the following steps: adding oxidized cellulose nanocrystals to deionized water, ultrasonically dispersing the cellulose nanocrystals, adding 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, stirring for 30-45 minutes, adding N-hydroxysuccinimide, shaking at room temperature for 1-1.5 hours, adding octadecylamine, ultrasonically treating for 2-2.5 hours, stirring for reaction for 2-2.5 hours, and washing the suspension with a 0.1M hydrochloric acid solution and anhydrous ethanol by centrifugation to obtain a modified cellulose nanocrystal suspension; The preparation method of the composite lignin lubricant comprises the following steps: adding benzotriazole and tetrabutylphosphonium hydroxide into a reaction vessel, reacting at room temperature for 8-9 hours, extracting the aqueous phase, vacuum distilling, adding anhydrous magnesium sulfate to dry the organic phase, filtering to obtain an ionic liquid; heating the ionic liquid to 90-95° C., adding lignin, and stirring uniformly to obtain the composite lignin lubricant; The proportions of each component in the preparation process of lignin-modified polyurethane are calculated by mass and include: 4-6.3 parts of hexamethylene diisocyanate, 0.01-0.02 parts of dibutyltin dilaurate, 1.4-16.1 parts of polycarbonate polyol, and 1-2 parts of lignin; in the preparation process of wear-resistant and anti-fingerprint coating, the mass ratio of lignin-cellulose composite filler: lignin-modified polyurethane is 3:(2-4).

2. The method for preparing a wear-resistant and anti-fingerprint coating according to claim 1, characterized in that: During the preparation of the modified cellulose nanocrystal suspension, the molar ratio of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide:N-hydroxysuccinimide:octadecylamine is 1:1:

1.

3. The method for preparing a wear-resistant and anti-fingerprint coating according to claim 1, characterized in that: The preparation process of the oxidized cellulose nanocrystals comprises the following steps: step (1): degumming sisal fibers to obtain degummed sisal fibers; Step (2): treating the degummed sisal fiber with alkali to obtain alkali-treated sisal fiber; Step (3): adding alkali-treated sisal fiber to deionized water, ultrasonically dispersing, adding sodium bromide and 2,2,6,6-tetramethylpiperidinium oxide, stirring at room temperature for 30-45 minutes, adding 12 wt% sodium hypochlorite aqueous solution under stirring, using a pH meter to detect the reaction system, and maintaining the pH of the reaction system at 10-10.5 by adding 1 wt% sodium hydroxide aqueous solution. When the reaction no longer consumes sodium hydroxide, adding anhydrous ethanol to terminate the reaction, centrifuging, collecting the precipitate, washing with deionized water until neutral, adding the precipitate to deionized water, ultrasonically treating, collecting the supernatant, centrifuging, collecting the precipitate, and freeze-drying to obtain oxidized cellulose nanocrystals.

4. The method for preparing a wear-resistant and anti-fingerprint coating according to claim 3, characterized in that: During the preparation of oxidized cellulose nanocrystals, the mass ratio of alkali-treated sisal fiber: sodium bromide: 2,2,6,6-tetramethylpiperidinyl oxide was 1:0.2:0.

02.

5. The method for preparing a wear-resistant and anti-fingerprint coating according to claim 1, characterized in that: During the preparation of the composite lignin lubricant, the molar ratio of benzotriazole to tetrabutylphosphonium hydroxide is 1:1, and the amount of lignin added is 1-5 wt% of the mass of the ionic liquid.

6. The method for preparing a wear-resistant and anti-fingerprint coating according to claim 1, characterized in that: During the preparation of the lignin-cellulose composite filler, the concentration of the lignin stock solution was 8 mg / mL, the concentration of the modified cellulose nanocrystal suspension was 4-16 mg / mL, and the volume ratio of the modified cellulose nanocrystal suspension: the lignin stock solution was 7:

3.

7. A wear-resistant and anti-fingerprint coating prepared according to the method for preparing a wear-resistant and anti-fingerprint coating according to any one of claims 1 to 6.

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