Antibacterial antiskid PU leather and preparation method and application thereof

Abstract

The invention discloses antibacterial and antiskid PU leather and a preparation method and application thereof, and belongs to the technical field of PU leather.The preparation method comprises the steps that a ZIF-8 / g-CNcomposite photocatalyst is obtained through an in-situ growth method, silver-doped nano-hydroxyapatite is prepared through an ion replacement method, the ZIF-8 / g-CNcomposite photocatalyst and the silver-doped nano-hydroxyapatite are compounded through liquid phase adsorption, and the antibacterial and antiskid PU leather is obtained. The preparation method comprises the following steps: preparing composite antibacterial powder, uniformly dispersing the composite powder into acrylamide, Arabic gum and polyethylene glycol methyl ether methacrylate serving as monomers, initiating polymerization to form composite coating slurry, performing oxygen plasma activation on PU leather, blade-coating the composite coating slurry, and curing to obtain the antibacterial antiskid PU leather. The material integrates the functions of self-cleaning, antibiosis, skid resistance and wear resistance.

Description

Technical Field

[0001] This invention belongs to the field of PU leather technology, specifically relating to an antibacterial and anti-slip PU leather, its preparation method, and its application. Background Technology

[0002] PU leather, short for polyurethane synthetic leather, is an artificial leather material made from polyurethane resin as the main raw material through coating, lamination and other processes. The polyurethane coating gives it a soft touch, good toughness and a certain degree of breathability. Compared with natural leather, it has the advantages of short production cycle, low cost, good environmental protection and flexible style design. Compared with PVC leather, it feels closer to natural leather and has better flexibility and durability. Therefore, it is widely used in footwear, bags and clothing, home decoration and automotive interiors.

[0003] However, conventional PU leather has a porous structure and certain hydrophilicity due to its polyurethane coating and fiber substrate, which makes it prone to the growth of bacteria, mold and other microorganisms in humid and warm environments. This can cause products to produce odors and cause skin itching, allergies or even bacterial infections. At the same time, its surface is relatively smooth, and the coefficient of friction is significantly reduced in humid environments, which can easily cause users to slip and fall. Therefore, it is necessary to prepare antibacterial and non-slip PU leather to make up for its shortcomings and meet higher standards of health, safety and use safety requirements.

[0004] Chinese invention patent application CN113684695A discloses a production process for water-based PU synthetic leather for automobiles. First, a modified polyurethane with silicon, fluorine groups and quaternary ammonium salt structure is synthesized through a multi-step reaction. Then, it is combined with nano-titanium dioxide modified with silane coupling agent to prepare a surface layer slurry and a foamed inner layer slurry, respectively. Then, a dense surface layer is formed by release paper transfer method, and a microporous foamed inner layer is formed on the base fabric. Finally, the two are combined with an adhesive to obtain a self-cleaning and long-lasting antibacterial water-based PU synthetic leather for automobiles.

[0005] Its self-cleaning mainly relies on the physical repulsion achieved by the superhydrophobicity of the surface. It is effective against dust and water droplets, but it is not good at cleaning low surface tension organic matter such as juice and oil. It is easy to wet and adhere to the surface, which is not only difficult to remove, but may also penetrate or chemically bond to the surface of the material, resulting in stubborn stains and spots, and accelerating the aging of the material. Summary of the Invention

[0006] The purpose of this invention is to provide an antibacterial and anti-slip PU leather, its preparation method, and its application. By constructing a multifunctional composite coating with ZIF-8 / g-C3N4 and silver-doped nano-hydroxyapatite as the core on the surface of a PU synthetic leather substrate, the invention effectively solves the problem of the failure of existing technologies that rely on superhydrophobic surfaces to clean organic pollutants such as grease and juice. Under light irradiation, ZIF-8 / g-C3N4 exerts a photocatalytic self-cleaning effect, which can degrade attached organic stains such as grease and juice and microorganisms. The silver ions continuously released from the hydroxyapatite can synergistically enhance antibacterial properties. The micro-nano rough surface formed by the composite antibacterial powder in the coating, combined with the viscoelasticity of the hydrogel, gives the coating excellent anti-slip properties, achieving self-cleaning, antibacterial, and anti-slip properties in one.

[0007] The objective of this invention can be achieved through the following technical solutions: A method for preparing antibacterial and non-slip PU leather includes the following steps: Step 1: Using the in-situ growth method, g-C3N4 is used as the nucleation site to grow ZIF-8 crystals on the surface of g-C3N4, thus obtaining the ZIF-8 / g-C3N4 composite photocatalyst.

[0008] Step 2: Silver-doped nano-hydroxyapatite was prepared by ion exchange method. The ZIF-8 / g-C3N4 composite photocatalyst and silver-doped nano-hydroxyapatite were then combined by liquid phase adsorption to obtain composite antibacterial powder.

[0009] Step 3: Using acrylamide, gum arabic, and polyethylene glycol methyl ether methacrylate as monomers, the composite powder is uniformly dispersed and polymerization is initiated to form a composite coating slurry. The PU leather with simulated leather texture printed on the surface is activated by oxygen plasma, the composite coating slurry is scraped and cured to obtain antibacterial and non-slip PU leather.

[0010] Furthermore, the specific preparation steps of the ZIF-8 / g-C3N4 composite photocatalyst are as follows: 2-Methylimidazole was dissolved in methanol to obtain a 2-methylimidazole methanol solution. Zinc nitrate and g-C3N4 were added to methanol and sonicated for 1-2 hours. The 2-methylimidazole methanol solution was then quickly added, and the mixture was sonicated for 30-50 minutes and then stirred for 8-10 hours. After centrifugation and separation, the mixture was vacuum dried to constant weight to obtain the ZIF-8 / g-C3N4 composite photocatalyst.

[0011] Furthermore, the ratio of 2-methylimidazole to methanol is 9.6-12.4 g: 360-500 mL.

[0012] Furthermore, the ratio of zinc nitrate, g-C3N4, methanol, and 2-methylimidazolium methanol solution is 3.78-5.42g: 7.56-10.68g: 360-500mL: 360-500mL.

[0013] Furthermore, the specific preparation steps of silver-doped nano-hydroxyapatite are as follows: Nano-hydroxyapatite was added to a 0.2 mol / L silver nitrate solution and stirred with a magnetic stirrer at room temperature and in the dark for 24-26 h at 300-400 rpm. After centrifugation at 10000-12000 rpm for 5-10 min, the mixture was filtered. The filter cake was washed 3-5 times with ultrapure water, and the product was collected. The product was calcined at 400-500℃ for 4-6 h and then ground to obtain silver-doped nano-hydroxyapatite.

[0014] Furthermore, the ratio of nano-hydroxyapatite to 0.2 mol / L silver nitrate solution is 10-12 g: 100-150 mL.

[0015] Furthermore, the specific preparation steps of the composite antibacterial powder are as follows: Silver-doped nano-hydroxyapatite was added to anhydrous ethanol and sonicated in an ice-water bath for 30-50 min to obtain a suspension. ZIF-8 / g-C3N4 composite photocatalyst was added to anhydrous ethanol and magnetically stirred at room temperature for 30-40 min. The suspension was slowly added dropwise and stirred at 40-50℃ for 6-8 h. After centrifugation, the precipitate was collected and washed alternately with anhydrous ethanol and deionized water 3-5 times. The precipitate was then vacuum dried to constant weight and ground into a fine powder to obtain a composite antibacterial powder.

[0016] Furthermore, the ratio of silver-doped nano-hydroxyapatite to anhydrous ethanol is 8-10g:800-1000mL.

[0017] Furthermore, the ratio of ZIF-8 / g-C3N4 composite photocatalyst, anhydrous ethanol, and suspension is 8-10g: 800-1000mL: 800-1000mL.

[0018] Furthermore, the specific preparation steps of the composite coating slurry are as follows: Add gum arabic, acrylamide, polyethylene glycol methyl ether methacrylate, and N,N'-methylenebisacrylamide to deionized water and stir at room temperature for 30-40 minutes. Add composite antibacterial powder and treat with ultrasonic radiation in a 300-400W ice-water bath for 40-60 minutes. Then add ammonium persulfate and N,N,N',N'-tetramethylethylenediamine and stir rapidly for 8-10 minutes to obtain the composite coating slurry.

[0019] Furthermore, the ratio of gum arabic, acrylamide, polyethylene glycol methyl ether methacrylate, N,N'-methylenebisacrylamide, deionized water, composite antibacterial powder, ammonium persulfate, and N,N,N',N'-tetramethylethylenediamine is 5-8g: 50-60g: 7.14-8.46mL: 0.135-0.215g: 200-500mL: 10-15g: 0.4-0.6g: 400-500μL.

[0020] Furthermore, the specific preparation steps for antibacterial and non-slip PU leather are as follows: Using post-processing high-solids printing technology, a simulated sheepskin texture with a natural and full feel is printed on the surface of PU synthetic leather. After curing at 50-60℃ for 2-5 minutes, textured PU leather is obtained. After pre-treatment with oxygen plasma for 5-10 minutes, an activated textured PU leather substrate is obtained. After applying the coating paste to the surface of the activated textured PU leather substrate, it is placed in an oven at 50-60℃ for 10-15 minutes to obtain antibacterial and non-slip PU leather.

[0021] This invention also provides the application of antibacterial and non-slip PU leather in the field of photocatalytic self-cleaning in materials that meet hygiene and safety requirements in high-frequency contact, enclosed spaces, and shared environments.

[0022] The beneficial effects of this invention are: 1. This invention designs a ZIF-8 / g-C3N4 composite photocatalyst and silver-doped nano-hydroxyapatite, and uses a liquid-phase adsorption method to form tightly bound nanocomposite functional units. These units are then uniformly dispersed in a gum arabic-reinforced hydrogel coating, achieving a dual synergistic effect of photocatalytic sterilization and silver ion slow-release sterilization. This endows the material with highly efficient, long-lasting, and broad-spectrum antibacterial properties. Simultaneously, the photocatalytic effect can completely decompose organic pollutants adhering to the surface, achieving active self-cleaning. Furthermore, the micro-nano rough structure constructed by the composite antibacterial powder in the coating, combined with the viscoelasticity of the hydrogel, gives the material excellent anti-slip properties and wear resistance in both dry and wet conditions. Oxygen plasma pretreatment and the introduction of gum arabic further ensure a strong interfacial bond between the coating and the substrate.

[0023] This process integrates multiple functions such as antibacterial, anti-slip, self-cleaning, and potential air purification in a single coating, significantly improving the hygiene, safety, and reliability of PU leather. It is particularly suitable for scenarios with stringent requirements for cleanliness, safety, and durability, such as automotive interiors and home furniture.

[0024] 2. The ZIF-8 / g-C3N4 composite photocatalyst in this invention effectively promotes the separation of photogenerated carriers by constructing a heterojunction structure, and achieves efficient adsorption of pollutants by relying on the porous characteristics of ZIF-8. It significantly broadens the spectral response range of the material and improves the yield of reactive oxygen species, thereby driving a highly efficient, visible light-responsive photocatalytic process and providing the core self-cleaning and antibacterial power for the coating. At the same time, it itself serves as an ideal nanocarrier and structural unit, providing an interfacial basis for the stable loading and synergistic effect of silver ions, which helps to form the micro-nano rough structure of the coating.

[0025] 3. The silver-doped nano-hydroxyapatite in this invention achieves long-term, controllable sustained release of silver ions through the stable combination of silver ions and the hydroxyapatite lattice, providing broad-spectrum contact antibacterial properties. The released silver ions can act as electron traps, synergistically with the ZIF-8 / g-C3N4 photocatalytic component, significantly improving photocatalytic efficiency by inhibiting photogenerated carrier recombination. In addition, its nanoscale hard particle characteristics help enhance the mechanical properties and wear resistance of the coating, and together with the composite photocatalyst, it constructs a stable micro-nano rough surface, enhancing the anti-slip effect of the coating.

[0026] 4. The composite antibacterial powder in this invention is made by tightly combining silver-doped nano-hydroxyapatite and ZIF-8 / g-C3N4 at the nanoscale through liquid-phase adsorption. This structure provides a heterogeneous interface for silver ions and photocatalytic components, realizing electron transfer and functional synergy, significantly enhancing antibacterial and self-cleaning efficacy. The powder, as a stable functional unit, ensures its uniform dispersion in the coating slurry and its firm bonding with the substrate, thereby ensuring the homogeneity and long-term durability of the coating performance. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments in the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1: A method for preparing antibacterial and non-slip PU leather, comprising the following steps: S1: Dissolve 9.6g of 2-methylimidazole in 360mL of methanol to obtain a 2-methylimidazole methanol solution; add 3.78g of zinc nitrate and 7.56g of g-C3N4 to 360mL of methanol, sonicate for 1h, then quickly add 360mL of the 2-methylimidazole methanol solution, sonicate for 30min, then stir for 8h, centrifuge and separate, and dry at 60℃ for 6h to obtain a ZIF-8 / g-C3N4 composite photocatalyst with an average particle size of 300nm.

[0029] The pre-dispersed g-C3N4 nanosheets have certain defect sites and functional groups on their surface, which can adsorb zinc ions in the solution and cause them to accumulate locally at the interface. The added 2-methylimidazole rapidly binds to the zinc ions at the interface through Zn–N coordination bonds, and nucleates and grows on the g-C3N4 surface, eventually forming ZIF-8 crystals.

[0030] S2: Add 10g of nano-hydroxyapatite to 100mL of 0.2mol / L silver nitrate solution, stir with a magnetic stirrer at room temperature and in the dark for 24h at 300rpm, centrifuge at 10000rpm for 5min, filter, wash the filter cake three times with ultrapure water, collect the product, calcine at 400℃ for 4h, grind and refine to obtain silver-doped nano-hydroxyapatite with an average particle size of 80nm.

[0031] Under light-protected conditions, through prolonged stirring, silver ions in the solution and calcium ions in the nano-hydroxyapatite crystal structure undergo a displacement reaction. Silver ions partially replace the original calcium ion sites in the crystal lattice and are thus integrated into the crystal structure of nano-hydroxyapatite, forming silver-doped nano-hydroxyapatite.

[0032] S3: Add 8g of silver-doped nano-hydroxyapatite to 800mL of anhydrous ethanol and sonicate in an ice-water bath for 30min to obtain a suspension; add 8g of ZIF-8 / g-C3N4 composite photocatalyst to 800mL of anhydrous ethanol and stir magnetically at room temperature for 30min, slowly add 800mL of the suspension, stir at 40℃ for 6h, centrifuge, collect the precipitate, wash the precipitate three times alternately with anhydrous ethanol and deionized water, vacuum dry at 60℃ for 6h, grind and refine to obtain composite antibacterial powder.

[0033] Nanocomposite materials are achieved by liquid-phase adsorption. In an ethanol medium, highly dispersed silver-doped nano-hydroxyapatite particles collide with a porous ZIF-8 / g-C3N4 support under Brownian motion and are firmly adsorbed and anchored to the surface and pores of the support through hydrogen bonding.

[0034] S4: Add 5g of gum arabic, 50g of acrylamide, 7.14mL of polyethylene glycol methyl ether methacrylate and 0.135g of N,N'-methylenebisacrylamide to 200mL of deionized water and stir at room temperature for 30min. Add 10g of composite antibacterial powder and treat with ultrasonic radiation in a 300W ice water bath for 40min. Then add 0.4g of ammonium persulfate and 400μL of N,N,N',N'-tetramethylethylenediamine and stir rapidly for 8min to obtain the composite coating slurry.

[0035] Acryloyl, gum arabic, and polyethylene glycol methyl ether methacrylate were selected as monomers for preparing the hydrogel coating. The addition of gum arabic can improve the adhesion of the hydrogel coating to the PU leather surface. Gum arabic molecules contain a large number of hydroxyl and carboxyl groups, which can crosslink the hydrogel coating with PU pretreated with oxygen plasma to form covalent bonds.

[0036] S5: Using post-processing high-solids printing technology, simulated sheepskin texture with a natural and full feel is printed on the surface of PU synthetic leather. It is cured at 50℃ for 2 minutes to set the texture and obtain textured PU leather. It is then pretreated with oxygen plasma for 5 minutes to obtain activated textured PU leather substrate. The coating paste is scraped onto the surface of the activated textured PU leather substrate and placed in a 50℃ oven for 10 minutes to obtain antibacterial and non-slip PU leather with a coating thickness of 0.3mm.

[0037] Example 2: A method for preparing antibacterial and anti-slip PU leather, comprising the following steps: S1: Dissolve 11.0 g of 2-methylimidazole in 430 mL of methanol to obtain a 2-methylimidazole methanol solution; add 4.60 g of zinc nitrate and 9.12 g of g-C3N4 to 430 mL of methanol, sonicate for 1.5 h, then quickly add 430 mL of the 2-methylimidazole methanol solution, sonicate for 40 min, then stir for 9 h, centrifuge and separate, and dry at 65 °C for 7 h to obtain a ZIF-8 / g-C3N4 composite photocatalyst with an average particle size of 300 nm.

[0038] S2: 11g of nano-hydroxyapatite was added to 125mL of 0.2mol / L silver nitrate solution and stirred with a magnetic stirrer at room temperature and in the dark for 25h at 350rpm. After centrifugation at 11000rpm for 7.5min, the mixture was filtered, and the filter cake was washed 4 times with ultrapure water. The product was collected, calcined at 450℃ for 5h, and then ground to obtain silver-doped nano-hydroxyapatite with an average particle size of 80nm.

[0039] S3: Add 9g of silver-doped nano-hydroxyapatite to 900mL of anhydrous ethanol and sonicate in an ice-water bath for 40min to obtain a suspension; add 9g of ZIF-8 / g-C3N4 composite photocatalyst to 900mL of anhydrous ethanol and stir magnetically at room temperature for 35min, slowly add 900mL of the suspension, stir at 45℃ for 7h, centrifuge, collect the precipitate, wash the precipitate alternately with anhydrous ethanol and deionized water 4 times, vacuum dry at 65℃ for 7h, grind and refine to obtain composite antibacterial powder.

[0040] S4: Add 6.5g gum arabic, 55g acrylamide, 7.80mL polyethylene glycol methyl ether methacrylate and 0.175g N,N'-methylenebisacrylamide to 350mL of deionized water and stir at room temperature for 35min. Add 12.5g of composite antibacterial powder and treat with ultrasonic radiation in a 350W ice water bath for 50min. Then add 0.5g ammonium persulfate and 450μL N,N,N',N'-tetramethylethylenediamine and stir rapidly for 9min to obtain the composite coating slurry.

[0041] S5: Using post-processing high-solids printing technology, a simulated sheepskin texture with a natural and full feel is printed on the surface of PU synthetic leather. It is cured at 55℃ for 3.5 minutes to set the texture and obtain textured PU leather. It is then pretreated with oxygen plasma for 7.5 minutes to obtain activated textured PU leather substrate. The coating slurry is then scraped onto the surface of the activated textured PU leather substrate and placed in a 55℃ oven for 12.5 minutes to obtain antibacterial and non-slip PU leather with a coating thickness of 0.3mm.

[0042] Example 3: A method for preparing antibacterial and anti-slip PU leather, comprising the following steps: S1: Dissolve 12.4g of 2-methylimidazole in 500mL of methanol to obtain a 2-methylimidazole methanol solution; add 5.42g of zinc nitrate and 10.68g of g-C3N4 to 500mL of methanol, sonicate for 2h, then quickly add 500mL of the 2-methylimidazole methanol solution, sonicate for 50min, then stir for 10h, centrifuge and separate, and dry at 70℃ for 8h to obtain a ZIF-8 / g-C3N4 composite photocatalyst with an average particle size of 300nm.

[0043] S2: 12g of nano-hydroxyapatite was added to 150mL of 0.2mol / L silver nitrate solution and stirred with a magnetic stirrer at room temperature and in the dark for 26h at 400rpm. After centrifugation at 12000rpm for 10min, the mixture was filtered, and the filter cake was washed 5 times with ultrapure water. The product was collected, calcined at 500℃ for 6h, and ground to obtain silver-doped nano-hydroxyapatite with an average particle size of 80nm.

[0044] S3: Add 10g of silver-doped nano-hydroxyapatite to 1000mL of anhydrous ethanol and sonicate in an ice-water bath for 50min to obtain a suspension; add 10g of ZIF-8 / g-C3N4 composite photocatalyst to 1000mL of anhydrous ethanol and stir magnetically at room temperature for 40min, slowly add 1000mL of the suspension, stir at 50℃ for 8h, centrifuge, collect the precipitate, wash the precipitate alternately with anhydrous ethanol and deionized water 5 times, vacuum dry at 70℃ for 8h, grind and refine to obtain composite antibacterial powder.

[0045] S4: Add 8g of gum arabic, 60g of acrylamide, 8.46mL of polyethylene glycol methyl ether methacrylate and 0.215g of N,N'-methylenebisacrylamide to 500mL of deionized water and stir at room temperature for 40min. Add 15g of composite antibacterial powder and treat with ultrasonic radiation in a 400W ice water bath for 60min. Then add 0.6g of ammonium persulfate and 500μL of N,N,N',N'-tetramethylethylenediamine and stir rapidly for 10min to obtain the composite coating slurry.

[0046] S5: Using post-processing high-solids printing technology, simulated sheepskin texture with a natural and full feel is printed on the surface of PU synthetic leather. It is cured at 60℃ for 5 minutes to set the texture and obtain textured PU leather. It is then pretreated with oxygen plasma for 10 minutes to obtain activated textured PU leather substrate. The coating paste is then scraped onto the surface of the activated textured PU leather substrate and placed in a 60℃ oven for 15 minutes to obtain antibacterial and non-slip PU leather with a coating thickness of 0.3mm.

[0047] In Examples 1-3, g-C3N was prepared according to the method described in the reference (Yang Tiantian. Construction of Z-type heterostructures of silver-modified barium titanate composite graphite carbon nitride and its photocatalytic performance study [D]. Donghua University, 2025.), with an average sheet thickness of 5-10 nm. Nano-hydroxyapatite was selected from Hubei Shuaiyan Ligao Biomedical Co., Ltd., CAS No. 1306-06-5, with an average particle size of 60 nm. Gum arabic was selected from Zhengzhou Yuhe Food Additives Co., Ltd., CAS No. 9000-01-5, with a mesh size of 100 μm. Acrylamide was selected from Shanghai Gaoming Chemical Co., Ltd., CAS No. 924-42-5, with a density of 0.2 (g / cm3). Polyethylene glycol methyl ether methacrylate was selected from Tianjin Development Zone Lotte Chemical Co., Ltd. Lotte Chemical Supermarket, CAS No. 26915-72-0, with a product number of 26915-72-0. N,N'-Methylenebisacrylamide was selected from Shandong Shengbang International Trade Co., Ltd., CAS No. 110-26-9; ammonium persulfate was selected from Jinan Jingyu Chemical Co., Ltd., CAS No. 7727-54-0; N,N,N',N'-tetramethylethylenediamine was selected from Jiangsu Pulesi Biotechnology Co., Ltd., CAS No. 110-18-9; the remaining raw materials were all commercially available products.

[0048] Comparative Example 1: The difference from Example 1 is that step S1 is omitted, and the ZIF-8 / g-C3N4 composite photocatalyst in step S3 is replaced with g-C3N4, while the other steps remain unchanged, and antibacterial and non-slip PU leather is prepared.

[0049] Comparative Example 2: The difference from Example 1 is that step S2 is omitted, and the silver-doped nano-hydroxyapatite in step S3 is replaced with commercially available nano-hydroxyapatite. The remaining steps remain unchanged, and antibacterial and non-slip PU leather is prepared.

[0050] Comparative Example 3: The difference from Example 1 is that step S3 is replaced by: dry mechanically mixing silver-doped nano-hydroxyapatite and ZIF-8 / g-C3N4 composite photocatalyst for 30 min to obtain mixed antibacterial powder; replacing the composite antibacterial powder in step S4 with mixed antibacterial powder, while keeping the other steps unchanged, to prepare antibacterial and non-slip PU leather.

[0051] This antibacterial and non-slip PU leather is especially suitable for contact surfaces with stringent requirements for hygiene, safety, and durability. It can be applied to the driver's seat, passenger seat, and rear seats of new energy vehicle brands, precisely addressing the high-frequency contact, enclosed space, and environment prone to bacterial growth and organic stains inside the vehicle. It is also suitable for various sofas, lounge chairs, and other upholstered furniture, meeting the protection needs of home settings for prolonged contact, multiple users, and occasional liquid spills, satisfying multiple application scenarios from travel to living.

[0052] The antibacterial and antislip PU leathers prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests: Static friction coefficient: Referring to GB / T3903.37-2021 "Test Methods for Static Friction Coefficient of Footwear Uppers and Linings", the static friction coefficient of the samples was tested under dry and wet conditions (0.1 mL / cm² water sprayed on the surface) with a normal load of 5 N and a slide speed of 100 mm / min using a material friction coefficient measuring instrument. The higher the static friction coefficient, the better the anti-slip performance of the material and the higher the safety.

[0053] Abrasion resistance: The Martindale abrasion tester was used with 400-grit sandpaper as the abrasive and a load of 100g. The number of friction cycles corresponding to the start of powder shedding was recorded. The higher the number of friction cycles, the better the abrasion resistance.

[0054] Antibacterial properties: Referring to GB / T20944.3-2008 "Evaluation of antibacterial properties of textiles - Part 3: Shaking method", Staphylococcus aureus and Escherichia coli suspensions were inoculated into the bacterial solution containing the sample at a concentration of (1.0-2.0)×10⁻⁶. 5 The antibacterial rate was calculated after contacting the material in a conical flask with CFU / mL at 37℃ and 150 rpm for 18 hours with shaking. The higher the antibacterial rate, the stronger the antibacterial effect of the material.

[0055] Long-lasting antibacterial properties: The samples that have undergone abrasion resistance testing are then subjected to the above antibacterial test to determine their antibacterial rate. The higher the antibacterial rate retention rate, the longer the antibacterial function of the material lasts.

[0056] Photocatalytic self-cleaning performance: The sample was added to a 10 mg / L methylene blue solution. After dark adsorption equilibrium was reached, the absorbance of the solution was measured at regular intervals under a 300 W xenon lamp with λ≥420 nm irradiation. The dye degradation rate was calculated within 3 hours.

[0057] The results are shown in Table 1: Table 1. Test Results of Antibacterial and Anti-slip PU Leather Performance project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Dry static friction coefficient 1.42 1.41 1.48 1.15 1.12 0.98 wet static friction coefficient 0.99 0.98 0.96 0.81 0.83 0.72 Abrasion resistance / times 10100 9800 9500 6500 7000 4800 Antibacterial rate - Staphylococcus aureus / % 99.9 99.9 99.9 85.5 65.4 92.5 Antibacterial rate - Escherichia coli / % 99.9 99.9 99.9 83.6 61.6 91.2 Antibacterial retention rate after wear resistance - Staphylococcus aureus / % 99.0 98.5 98.0 78.5 38.5 82.3 Degradation rate / % 97.2 96.3 95.1 32.8 71.7 76.8 As can be seen from Table 1, the antibacterial and antislip PU leather prepared in Examples 1-3 of the present invention is superior to Comparative Examples 1-3 in terms of antislip, wear resistance, antibacterial and photocatalytic self-cleaning properties.

[0058] The degradation rate in Comparative Example 1 decreased significantly, possibly due to the lack of modification with ZIF-8 crystals. The specific surface area and surface roughness of the unloaded ZIF-8 g-C3N4 nanosheets were significantly reduced, failing to provide sufficient active sites and pollutant adsorption sites for the photocatalytic reaction. Furthermore, the absence of the heterojunction structure composed of ZIF-8 and g-C3N4 resulted in an extremely high recombination rate of photogenerated electrons and holes, severely weakening the material's ability to generate reactive oxygen species under visible light, thus rendering the photocatalytic self-cleaning function essentially ineffective.

[0059] The significant decrease in antibacterial rate in Comparative Example 2 may be due to the lack of slow-release bactericidal effect of silver ions provided by silver-doped nano-hydroxyapatite. Undoped nano-hydroxyapatite itself does not have significant antibacterial activity, and the coating mainly relies on limited photocatalytic effect. The antibacterial spectrum and efficiency are seriously insufficient. At the same time, since there is no continuous release of silver ions from the crystal lattice, the coating cannot maintain an effective antibacterial concentration on the surface after being worn, resulting in its antibacterial function not being durable. Once the physical barrier is damaged, the antibacterial performance deteriorates rapidly.

[0060] The significant decrease in static friction coefficient and wear resistance in Comparative Example 3 is likely due to the lack of uniform nanoscale composite and firm anchoring achieved by liquid-phase adsorption. Dry mechanical blending struggles to achieve uniform dispersion and tight interfacial bonding of silver-doped nano-hydroxyapatite and ZIF-8 / g-C3N4 at the nanoscale, easily leading to particle agglomeration. These agglomerates form dispersion defects in the coating, making it difficult to construct a uniform and abundant micro / nano rough surface structure to improve the friction coefficient. They also become stress concentration points in the matrix, weakening the coating's cohesion and making it more prone to pulverization or peeling under frictional forces, thus significantly reducing the coating's wear life and overall durability.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing antibacterial and anti-slip PU leather, characterized in that, Includes the following steps: Step 1: Using the in-situ growth method, g-C3N4 is used as the nucleation site to grow ZIF-8 crystals on the surface of g-C3N4, thus obtaining the ZIF-8 / g-C3N4 composite photocatalyst. Step 2: Silver-doped nano-hydroxyapatite was prepared by ion exchange method; ZIF-8 / g-C3N4 composite photocatalyst and silver-doped nano-hydroxyapatite were combined by liquid phase adsorption to obtain composite antibacterial powder; Step 3: Using acrylamide, gum arabic, and polyethylene glycol methyl ether methacrylate as monomers, the composite powder is uniformly dispersed and polymerization is initiated to form a composite coating slurry. The PU leather with simulated leather texture printed on the surface is activated by oxygen plasma, the composite coating slurry is scraped and cured to obtain antibacterial and non-slip PU leather.

2. The method for preparing antibacterial and anti-slip PU leather according to claim 1, characterized in that, The specific preparation steps of the ZIF-8 / g-C3N4 composite photocatalyst are as follows: 2-Methylimidazole was dissolved in methanol at a ratio of 9.6-12.4 g: 360-500 mL to prepare a 2-methylimidazole methanol solution. Zinc nitrate and g-C3N4 were added to methanol and sonicated for 1-2 h. The 2-methylimidazole methanol solution was then quickly added, sonicated for 30-50 min, and stirred for 8-10 h. After centrifugation and separation, the solution was vacuum dried to constant weight to obtain the ZIF-8 / g-C3N4 composite photocatalyst. The ratio of zinc nitrate, g-C3N4, methanol, and 2-methylimidazolium methanol solution is 3.78-5.42g: 7.56-10.68g: 360-500mL: 360-500mL.

3. The method for preparing antibacterial and anti-slip PU leather according to claim 1, characterized in that, The specific preparation steps of the silver-doped nano-hydroxyapatite are as follows: Nano-hydroxyapatite was added to a 0.2 mol / L silver nitrate solution and stirred with a magnetic stirrer at room temperature and in the dark for 24-26 h at 300-400 rpm. After centrifugation at 10000-12000 rpm for 5-10 min, the mixture was filtered. The filter cake was washed with ultrapure water 3-5 times, and the product was collected. The product was calcined at 400-500℃ for 4-6 h and then ground to obtain silver-doped nano-hydroxyapatite. The ratio of nano-hydroxyapatite to 0.2 mol / L silver nitrate solution is 10-12 g: 100-150 mL.

4. The method for preparing antibacterial and anti-slip PU leather according to claim 1, characterized in that, The specific preparation steps of the composite antibacterial powder are as follows: Silver-doped nano-hydroxyapatite was added to anhydrous ethanol and sonicated in an ice-water bath for 30-50 min to obtain a suspension. ZIF-8 / g-C3N4 composite photocatalyst was added to anhydrous ethanol and magnetically stirred at room temperature for 30-40 min. The suspension was slowly added dropwise and stirred at 40-50℃ for 6-8 h. After centrifugation, the precipitate was collected and washed alternately with anhydrous ethanol and deionized water 3-5 times. The precipitate was then vacuum dried to constant weight and ground into a fine powder to obtain a composite antibacterial powder.

5. The method for preparing an antibacterial and anti-slip PU leather according to claim 4, characterized in that, The ratio of silver-doped nano-hydroxyapatite to anhydrous ethanol is 8-10g:800-1000mL; The ratio of the ZIF-8 / g-C3N4 composite photocatalyst, anhydrous ethanol, and suspension is 8-10g: 800-1000mL: 800-1000mL.

6. The method for preparing an antibacterial and anti-slip PU leather according to claim 1, characterized in that, The specific preparation steps of the composite coating slurry are as follows: Add gum arabic, acrylamide, polyethylene glycol methyl ether methacrylate, and N,N'-methylenebisacrylamide to deionized water and stir at room temperature for 30-40 minutes. Add composite antibacterial powder and treat with ultrasonic radiation in a 300-400W ice-water bath for 40-60 minutes. Then add ammonium persulfate and N,N,N',N'-tetramethylethylenediamine and stir rapidly for 8-10 minutes to obtain the composite coating slurry.

7. The method for preparing an antibacterial and anti-slip PU leather according to claim 6, characterized in that, The ratio of gum arabic, acrylamide, polyethylene glycol methyl ether methacrylate, N,N'-methylenebisacrylamide, deionized water, composite antibacterial powder, ammonium persulfate, and N,N,N',N'-tetramethylethylenediamine is 5-8g: 50-60g: 7.14-8.46mL: 0.135-0.215g: 200-500mL: 10-15g: 0.4-0.6g: 400-500μL.

8. The method for preparing an antibacterial and anti-slip PU leather according to claim 1, characterized in that, The specific preparation steps for the antibacterial and anti-slip PU leather are as follows: Using post-processing high-solids printing technology, a simulated sheepskin texture with a natural and full feel is printed on the surface of PU synthetic leather. After curing at 50-60℃ for 2-5 minutes, textured PU leather is obtained. After pre-treatment with oxygen plasma for 5-10 minutes, an activated textured PU leather substrate is obtained. After applying the coating paste to the surface of the activated textured PU leather substrate, it is placed in an oven at 50-60℃ for 10-15 minutes to obtain antibacterial and non-slip PU leather.

9. An antibacterial and anti-slip PU leather, prepared according to any one of claims 1-8.

10. The application of the antibacterial and anti-slip PU leather as described in claim 9 in photocatalytic self-cleaning.