A wear-resistant and antibacterial composite leather for electronic skin and its preparation method

Abstract

This invention relates to the field of crystal materials technology, specifically disclosing a wear-resistant and antibacterial composite leather for electronic skin and its preparation method. The composite leather is composed of delimed bare leather, plant polyphenols, glutaraldehyde, lysine-chitosan graft polymer, tannic acid-zirconium coordination oligomer solution, plant-derived wax esters, and lipase. The preparation method includes: adding plant polyphenols and glutaraldehyde to the delimed bare leather for tanning to obtain primary cross-linked raw leather; adjusting the pH and then adding lysine-chitosan graft polymer and tannic acid-zirconium coordination oligomer for an antibacterial mineralization reaction; then adding plant-derived wax esters and lipase for an enzyme-catalyzed transesterification reaction; finally, drying, rehydrating, and softening to obtain the finished product. This invention, through the synergistic effect of multi-stage processes including composite tanning, synergistic antibacterial action, and enzyme-catalyzed lubrication, enables the composite leather to possess excellent wear resistance, long-lasting antibacterial properties, high breathability, and good softness, making it suitable for wearable devices such as electronic skin and showing promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of crystal materials technology, specifically to a wear-resistant and antibacterial composite leather for electronic skin and its preparation method. Background Technology

[0002] Leather is a bio-based material made from natural animal hides through processes such as tanning. Its main component is type I collagen. Due to its excellent softness, breathability, and skin-friendliness, leather has long been widely used in clothing, footwear, and wearable products. With the development of wearable technology, leather, due to its natural biocompatibility and comfort, is considered a suitable material substrate for electronic skin applications.

[0003] However, ordinary leather still has certain limitations in practical use. On the one hand, under repeated friction, bending, or stress, the surface fiber structure of leather is prone to wear, resulting in pilling, shedding, or even localized structural damage, thus affecting the material's service life and appearance stability. This insufficient abrasion resistance is particularly pronounced in scenarios involving prolonged skin contact or high-frequency contact.

[0004] On the other hand, leather is a natural protein material, which easily provides conditions for the growth of bacteria and fungi in humid and warm environments, leading to odors, hygiene and safety hazards, and even skin irritation. Therefore, endowing leather with stable and long-lasting antibacterial properties is of great significance for improving its safety and comfort in skin-contact applications.

[0005] To address the aforementioned issues, various modification schemes for abrasion-resistant or antibacterial leather have been proposed in existing technologies. For example, abrasion resistance can be improved by coating the leather surface with abrasion-resistant resin or polymer coatings, or by impregnating or spraying antibacterial agents to inhibit microbial growth. However, these technical solutions still have certain shortcomings: First, some abrasion-resistant coatings are quite thick or have a high degree of cross-linking, which can easily reduce the original softness and breathability of the leather, affecting wearing comfort; second, antibacterial components mostly exist through physical adsorption or surface adhesion, and are prone to detachment during long-term friction or repeated use, leading to a decrease in antibacterial effect; third, abrasion resistance modification and antibacterial modification are often carried out separately, lacking synergistic design between the two, making it difficult to balance long-term durability and functional stability.

[0006] Based on the above statements, the present invention provides a wear-resistant and antibacterial composite leather for electronic skin and a method for preparing the same. Summary of the Invention

[0007] To address the problems of insufficient abrasion resistance, easy bacterial growth, and poor functional stability of existing leathers during long-term skin contact, as well as the tendency of existing modification methods to reduce the breathability and softness of leather, this invention provides an abrasion-resistant and antibacterial composite leather for electronic skin and its preparation method.

[0008] In a first aspect, the present invention provides a wear-resistant and antibacterial composite leather for electronic skin, employing the following technical solution: A wear-resistant and antibacterial composite leather for electronic skin comprises the following raw materials in parts by weight: 100-120 parts of de-ashed bare leather, 5-15 parts of plant polyphenols, 0.8-2.0 parts of glutaraldehyde, 2-6 parts of lysine-chitosan graft, 1-5 parts of tannic acid-zirconium coordination oligomer solution, 2-6 parts of plant-derived wax esters, and 0.1-0.3 parts of lipase.

[0009] Preferably, the preparation method of the deashed bare skin is as follows: take fresh animal skin, remove hair and immerse it in a biological degreasing agent for degreasing, and wash it; then immerse it in a deashing solution and stir to deash it, and wash it; then immerse it in an enzyme softening agent to soften it, and wash it; finally, freeze dry it under vacuum to obtain the deashed bare skin.

[0010] Preferably, the specific preparation method of the deashed bare hide is as follows: Take fresh animal hide, remove the hair, and immerse it in a biological degreasing agent (composed of soybean lecithin, Tween 80, and deionized water in a mass ratio of 2-3:1:100) at a mass ratio of 1:30-40, degrease at 30-40°C for 30-60 minutes, and wash with deionized water 2-4 times; then immerse it in a deashing solution (composed of ammonium chloride, fatty alcohol polyoxyethylene ether, and deionized water in a mass ratio of 1-2:0.2-0.4:100) at a mass ratio of 1:30-50, at a temperature of 25-35°C and a pH of 8.5-9.5, and stir at 300-500 rpm for 50 minutes to deash. Wash with deionized water 2-4 times for 90 min; then immerse in an enzyme softening agent (composed of trypsin, lipase and deionized water in a mass ratio of 1:1-1.5:100, with trypsin activity of 3000-5000 U / g and lipase activity of 20000-25000 U / g) at a mass ratio of 1:20-30, soften at 30-35°C for 20-40 min, and wash with deionized water 2-4 times; finally freeze-dry to constant weight at -50°C to -60°C and vacuum degree ≤10Pa to obtain de-ashed bare skin with a thickness of 0.1-0.5 mm and a water vapor permeability ≥1000 g / (m²·24h).

[0011] Preferably, the animal skin is one of cowhide, sheepskin, or pigskin.

[0012] Preferably, the plant polyphenols are composed of taratanine and tea polyphenols in a mass ratio of 1-2:1.

[0013] Preferably, the preparation method of the lysine-chitosan graft is as follows: dissolve chitosan in acetic acid solution, add EDC·HCl and NHS for activation, add lysine solution dropwise, stir the reaction at room temperature, dialyze and freeze dry to obtain the lysine-chitosan graft.

[0014] Preferably, the specific preparation method of the lysine-chitosan graft is as follows: dissolve chitosan in an acetic acid solution with a mass concentration of 1-2% to prepare a chitosan solution with a mass concentration of 0.5-1.5%; add EDC·HCl and NHS to the chitosan solution at a mass ratio of 1.2-2.0:0.4-0.5:100-150, and activate at 25-30℃ for 30-60 min to obtain an activated solution; add... Add 5-10 wt% lysine solution dropwise to the activation solution and stir at 200-400 rpm for 6-12 h at room temperature. After the reaction is completed, place the reaction solution in a dialysis bag with a molecular weight cutoff of 3000-5000 Da and dialyze with deionized water for 24-48 h, changing the deionized water every 6-8 h. Finally, freeze-dry to constant weight at -50°C to -60°C and vacuum degree ≤10 Pa to obtain the lysine-chitosan graft.

[0015] Preferably, the tannic acid-zirconium coordination oligomer solution is prepared by: adding zirconium oxychloride solution dropwise to tannic acid solution, heating and stirring to react, and then cooling to obtain the tannic acid-zirconium coordination oligomer solution.

[0016] Preferably, the specific preparation method of the tannic acid-zirconium coordination oligomer solution is as follows: according to the molar ratio of tannic acid to zirconium oxychloride 1:0.8-1.2, first, 0.5-2.0 wt% of tannic acid solution is placed in a constant temperature water bath and preheated to 40-60℃, then 1.0-3.0 wt% of zirconium oxychloride solution is added dropwise to the tannic acid solution at a rate of 2.5 mL / s, and the reaction is stirred at 40-60℃ and 200-400 rpm for 1.5-3.0 h; after the reaction is completed, it is cooled to room temperature to obtain the tannic acid-zirconium coordination oligomer solution.

[0017] Preferably, the plant-derived wax ester is composed of jojoba oil and rice bran wax in a mass ratio of 2-3:1.

[0018] Preferably, the lipase has an enzyme activity of 10,000-30,000 U / g.

[0019] Secondly, the present invention provides a method for preparing wear-resistant and antibacterial composite leather for electronic skin, employing the following technical solution: A method for preparing abrasion-resistant and antibacterial composite leather for electronic skin includes the following steps: S1. Plant polyphenols and glutaraldehyde are added to delimed bare leather and tanned to obtain primary cross-linked raw leather; S2. Adjust the pH of the primary cross-linked raw leather to 5.5-6.5, add lysine-chitosan graft and tannic acid-zirconium coordination oligomer solution, and react at 35-40°C for 2-3 hours to obtain antibacterial mineralized raw leather. S3. Plant-derived wax esters and lipases are added to antibacterial mineralized raw leather to carry out an enzyme-catalyzed transesterification reaction to obtain lubricated raw leather. S4. Dry, rehydrate, and soften the lubricated raw leather to obtain wear-resistant and antibacterial composite leather for electronic skin with a thickness of 0.3-0.8mm.

[0020] Preferably, the tanning temperature in step S1 is 25-35°C and the tanning time is 2-4 hours.

[0021] Preferably, in step S3, the temperature for enzyme-catalyzed transesterification is 45-50°C, and the time for enzyme-catalyzed transesterification is 30-60 min.

[0022] In summary, the present invention has the following beneficial effects: 1. Excellent wear resistance, suitable for long-term use of electronic skin: This invention utilizes the primary cross-linking system of "plant polyphenols + glutaraldehyde" and the mineralization enhancement effect of "tannic acid-zirconium coordination oligomers" to form a dense and stable cross-linking network and inorganic reinforcing phase between leather fibers, significantly improving the structural strength and surface wear resistance of the leather. At the same time, plant-derived wax esters can be uniformly coated on the surface of leather fibers after enzyme-catalyzed ester exchange, forming a lubricating protective layer, further reducing friction loss and solving the problem of easy wear and tear of existing leathers when used in close contact with the skin for a long time.

[0023] 2. Significant and long-lasting antibacterial effect: The lysine-chitosan graft retains the natural antibacterial activity of chitosan, while the introduction of lysine enhances its water solubility and binding ability with leather fibers, allowing it to be firmly anchored in the leather matrix; the zirconium ions in the tannic acid-zirconium coordination oligomer can disrupt the bacterial cell membrane structure, forming a synergistic antibacterial effect with chitosan, achieving highly effective inhibition of a variety of common pathogenic bacteria (such as Escherichia coli and Staphylococcus aureus); and the antibacterial components bind to the leather through chemical cross-linking or coordination, rather than simple physical adsorption, effectively avoiding the loss of antibacterial components during use and ensuring the antibacterial stability for long-term skin contact.

[0024] 3. Strong functional stability and excellent environmental adaptability: During the preparation process, the functional components (antibacterial, wear-resistant, and lubricating components) form a stable chemical or physical bond with the leather fibers through multi-level cross-linking and mineralization. Under conditions such as long-term skin contact with sweat and friction, the functional components are not prone to falling off or performance degradation. At the same time, reasonable process parameter control (such as mild tanning and mineralization temperatures) avoids excessive shrinkage or degradation of the leather fibers, further ensuring the long-term stability of the overall performance of the composite leather.

[0025] 4. Enhancing breathability and softness for improved skin comfort: This invention employs a gentle de-ashed raw leather preparation process. By precisely controlling the enzyme softening conditions, impurities in the leather are removed while preserving the natural porous structure of the leather fibers to the maximum extent, ensuring the composite leather's excellent water vapor permeability (derived from the basic advantage of de-ashed raw leather with a water vapor permeability of ≥1000g / (m²·24h)). The subsequent enzymatic ester exchange reaction of plant-derived wax esters further optimizes the lubricity of the leather fibers and improves the leather's softness. This solves the problems of poor breathability and hard feel caused by excessive cross-linking or the addition of a large amount of inorganic fillers in existing modified leathers, thus meeting the comfort requirements for electronic skin contact.

[0026] 5. The preparation process is green and controllable, with good prospects for industrialization: The raw materials used in this invention (such as plant polyphenols, chitosan, plant-derived wax esters, etc.) are mostly natural or bio-based materials, which are environmentally friendly; the pretreatment processes such as deashing, degreasing, and softening are mild and have no harmful pollutant emissions; the parameters of each preparation step are clear and highly controllable, and the tannic acid-zirconium coordination oligomer can directly participate in the reaction in solution form without the need for additional complex steps such as freeze drying, which simplifies the process flow, reduces production costs, and is conducive to large-scale industrial production. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0028] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0029] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available products.

[0030] Taratanin was purchased from Hunan Beiya Biotechnology Co., Ltd.

[0031] The tea polyphenols were purchased from Shaanxi Benhe Bioengineering Co., Ltd., with a specification of 98% tea polyphenols.

[0032] Jojoba oil was purchased from Wanyi Spice Oil Co., Ltd. in Ji'an City.

[0033] The rice bran wax was purchased from Shanghai Jingyan Chemical Co., Ltd.

[0034] Glutaraldehyde was purchased from Shanghai Moen Chemical Technology Co., Ltd., CAS No.: 111-30-8.

[0035] Examples 1-3 provide a wear-resistant and antibacterial composite leather for electronic skin and its preparation method.

[0036] Example 1 A wear-resistant and antibacterial composite leather for electronic skin comprises the following raw materials in parts by weight: 100 parts of de-ashed bare leather, 5 parts of plant polyphenols, 0.8 parts of glutaraldehyde, 2 parts of lysine-chitosan graft, 1 part of tannic acid-zirconium coordination oligomer solution, 2 parts of plant-derived wax esters, and 0.1 parts of lipase.

[0037] The specific preparation method for the degreased raw hide is as follows: Take fresh cowhide, mechanically remove the hair, and then immerse it in a biological degreasing agent (composed of soybean lecithin, Tween 80, and deionized water in a mass ratio of 2:1:100) at a mass ratio of 1:30. Degrease at 30°C for 30 minutes, and wash twice with deionized water; then immerse it in a solution at a temperature of 25°C and pH at a mass ratio of 1:30. The ash was removed from the deashing solution (composed of ammonium chloride, fatty alcohol polyoxyethylene ether and deionized water in a mass ratio of 1:0.2:100) at 8.5 rpm for 50 min by stirring, and then washed twice with deionized water. Subsequently, the ash was removed from the solution at a mass ratio of 1:20 by immersion in an enzyme softening agent (composed of trypsin, lipase and deionized water in a mass ratio of 1:1:100, with trypsin activity of 3000 U / g and lipase activity of 20000 U / g) at 30°C for 20 min by washing twice with deionized water. Finally, the ash was freeze-dried to constant weight at -50°C and a vacuum degree of 10 Pa to obtain a deashed bare skin with a thickness of 0.5 mm and a water vapor permeability of 1000 g / (m²·24h).

[0038] Plant polyphenols are composed of taratanine and tea polyphenols in a 1:1 mass ratio.

[0039] The specific preparation method of lysine-chitosan graft is as follows: Chitosan is dissolved in a 1% (w / w) acetic acid solution to prepare a 0.5% (w / w) chitosan solution; EDC·HCl and NHS are added to the chitosan solution at a mass ratio of 1.2:0.4:100, and activated at 25°C for 30 min to obtain an activated solution; 5 wt% lysine solution is added dropwise to the activated solution at a molar ratio of chitosan to lysine of 1:1 at a rate of 2.5 mL / s, and the mixture is stirred at 200 rpm for 6 h at room temperature. After the reaction is completed, the reaction solution is placed in a dialysis bag with a molecular weight cutoff of 3000 Da and dialyzed with deionized water for 24 h, with the deionized water being replaced every 6 h. Finally, the mixture is freeze-dried at -50°C and a vacuum of 10 Pa to constant weight to obtain the lysine-chitosan graft.

[0040] The specific preparation method of the tannic acid-zirconium coordination oligomer solution is as follows: according to the molar ratio of tannic acid to zirconium oxychloride 1:0.8, first place a 0.5wt% tannic acid solution in a constant temperature water bath and preheat it to 40℃, then add a 1.0wt% zirconium oxychloride solution dropwise to the tannic acid solution at a rate of 2.5mL / s, and stir the reaction at 40℃ and 200rpm for 1.5h; after the reaction is completed, cool to room temperature to obtain the tannic acid-zirconium coordination oligomer solution.

[0041] Plant-derived wax esters are composed of jojoba oil and rice bran wax in a mass ratio of 2:1.

[0042] A method for preparing abrasion-resistant and antibacterial composite leather for electronic skin includes the following steps: S1. Add plant polyphenols and glutaraldehyde to the delimed bare leather and tan at 25°C for 2 hours to obtain primary cross-linked raw leather. S2. The pH of the primary cross-linked raw leather was adjusted to 5.5 using a 1wt% acetic acid solution. Lysine-chitosan graft and tannic acid-zirconium coordination oligomer solution were added and reacted at 35°C for 2 hours to obtain antibacterial mineralized raw leather. S3. Plant-derived wax esters and lipase with an enzyme activity of 10000 U / g were added to the antibacterial mineralized raw leather, and the enzyme-catalyzed transesterification reaction was carried out at 45°C for 30 min to obtain lubricated raw leather. S4. Dry the lubricated raw leather with hot air at 50°C to a moisture content of 10%, then rehydrate it with deionized water to a moisture content of 20%, and then soften it by tumbling at 25°C and 20 rpm for 30 minutes to obtain a wear-resistant and antibacterial composite leather for electronic skin with a thickness of 0.8 mm.

[0043] Example 2 A wear-resistant and antibacterial composite leather for electronic skin comprises the following raw materials in parts by weight: 110 parts of de-ashed bare leather, 10 parts of plant polyphenols, 1.4 parts of glutaraldehyde, 4 parts of lysine-chitosan graft, 3 parts of tannic acid-zirconium coordination oligomer solution, 4 parts of plant-derived wax esters, and 0.2 parts of lipase.

[0044] The specific preparation method for de-ashed raw hide is as follows: Take fresh cowhide, remove the hair mechanically, and then immerse it in a biological degreasing agent (composed of soybean lecithin, Tween 80, and deionized water in a mass ratio of 2.5:1:100) at a mass ratio of 1:35. Degrease at 35°C for 45 minutes, and wash three times with deionized water. Then, immerse it in a de-ashing solution (composed of ammonium chloride, fatty alcohol polyoxyethylene ether, and deionized water in a mass ratio of 1.5:0.3:100) at a mass ratio of 1:40 at a temperature of 30°C and a pH of 9, and stir at 400 rpm to remove ash. The ash was removed and washed three times with deionized water for 70 minutes. Then, it was immersed in an enzyme softening agent (composed of trypsin, lipase and deionized water in a mass ratio of 1:1.2:100, with trypsin activity of 4000 U / g and lipase activity of 22000 U / g) at a mass ratio of 1:25, softened at 32°C for 30 minutes, and washed three times with deionized water. Finally, it was freeze-dried to constant weight at -55°C and a vacuum degree of 10 Pa to obtain a deashed bare skin with a thickness of 0.3 mm and a water vapor permeability of 1100 g / (m²·24h).

[0045] Plant polyphenols are composed of taratanine and tea polyphenols in a mass ratio of 1.5:1.

[0046] The specific preparation method of lysine-chitosan graft is as follows: Chitosan is dissolved in a 1.5% (w / w) acetic acid solution to prepare a 1% (w / w) chitosan solution; EDC·HCl and NHS are added to the chitosan solution at a mass ratio of 1.6:0.45:125, and activated at 27°C for 45 min to obtain an activated solution; 7.5 wt% lysine solution is added dropwise to the activated solution at a rate of 2.5 mL / s at a molar ratio of chitosan to lysine of 1:1.2, and the mixture is stirred at 300 rpm for 9 h at room temperature. After the reaction is completed, the reaction solution is placed in a dialysis bag with a molecular weight cutoff of 4000 Da and dialyzed with deionized water for 36 h, with the deionized water being replaced every 7 h. Finally, the mixture is freeze-dried at -55°C and a vacuum of 10 Pa to constant weight to obtain the lysine-chitosan graft.

[0047] The specific preparation method of the tannic acid-zirconium coordination oligomer solution is as follows: according to the molar ratio of tannic acid to zirconium oxychloride 1:1, first place a 1.5wt% tannic acid solution in a constant temperature water bath and preheat it to 50℃, then add a 2.0wt% zirconium oxychloride solution dropwise to the tannic acid solution at a rate of 2.5mL / s, and stir the reaction at 50℃ and 300rpm for 2h; after the reaction is completed, cool to room temperature to obtain the tannic acid-zirconium coordination oligomer solution.

[0048] Plant-derived wax esters are composed of jojoba oil and rice bran wax in a mass ratio of 2.5:1.

[0049] A method for preparing abrasion-resistant and antibacterial composite leather for electronic skin includes the following steps: S1. Add plant polyphenols and glutaraldehyde to the delimed bare leather and tan at 30°C for 3 hours to obtain primary cross-linked raw leather. S2. The pH of the primary cross-linked raw leather was adjusted to 6 using a 2wt% acetic acid solution. Lysine-chitosan graft and tannic acid-zirconium coordination oligomer solution were added and reacted at 37°C for 2.5 h to obtain antibacterial mineralized raw leather. S3. Plant-derived wax esters and lipase with an enzyme activity of 20000 U / g were added to the antibacterial mineralized raw leather, and an enzyme-catalyzed transesterification reaction was carried out at 47°C for 45 min to obtain lubricated raw leather. S4. The lubricated raw leather is dried with hot air at 55°C to a moisture content of 12%, then rehydrated with deionized water to a moisture content of 22%, and then softened by tumbling at 30°C and 25 rpm for 45 minutes to obtain a wear-resistant and antibacterial composite leather for electronic skin with a thickness of 0.5 mm.

[0050] Example 3 A wear-resistant and antibacterial composite leather for electronic skin comprises the following raw materials in parts by weight: 120 parts of de-ashed bare leather, 15 parts of plant polyphenols, 2.0 parts of glutaraldehyde, 6 parts of lysine-chitosan graft, 5 parts of tannic acid-zirconium coordination oligomer solution, 6 parts of plant-derived wax esters, and 0.3 parts of lipase.

[0051] The specific preparation method for the degreased raw hide is as follows: Take fresh cowhide, remove the hair mechanically, and then immerse it in a biological degreasing agent (composed of soybean lecithin, Tween 80, and deionized water in a mass ratio of 3:1:100) at a mass ratio of 1:40. Degrease at 40°C for 60 minutes, and wash four times with deionized water. Then immerse it in a solution at a mass ratio of 1:50 at a temperature of 35°C and pH... The ash removal solution (composed of ammonium chloride, fatty alcohol polyoxyethylene ether, and deionized water in a mass ratio of 2:0.4:100) was stirred at 500 rpm for 90 min to remove ash, and then washed four times with deionized water. Subsequently, the ash removal solution was immersed in an enzyme softening agent (composed of trypsin, lipase, and deionized water in a mass ratio of 1:1.5:100, with trypsin activity of 5000 U / g and lipase activity of 25000 U / g) at a mass ratio of 1:30, softened at 35°C for 40 min, and washed four times with deionized water. Finally, the ash removal solution was freeze-dried at -60°C and a vacuum degree of 10 Pa to a constant weight to obtain a ash removal solution with a thickness of 0.1 mm and a water vapor permeability of 1200 g / (m²·24h).

[0052] Plant polyphenols are composed of taratanine and tea polyphenols in a mass ratio of 2:1.

[0053] The specific preparation method of lysine-chitosan graft is as follows: Chitosan is dissolved in a 2% (w / w) acetic acid solution to prepare a 1.5% (w / w) chitosan solution; EDC·HCl and NHS are added to the chitosan solution at a mass ratio of 2.0:0.5:150, and activated at 30°C for 60 min to obtain an activated solution; 10 wt% lysine solution is added dropwise to the activated solution at a molar ratio of chitosan to lysine of 1:1.5 at a rate of 2.5 mL / s, and the mixture is stirred at 400 rpm for 12 h at room temperature. After the reaction is completed, the reaction solution is placed in a dialysis bag with a molecular weight cutoff of 5000 Da and dialyzed with deionized water for 48 h, with the deionized water being replaced every 8 h. Finally, the mixture is freeze-dried at -60°C and a vacuum of 10 Pa to constant weight to obtain the lysine-chitosan graft.

[0054] The specific preparation method of the tannic acid-zirconium coordination oligomer solution is as follows: according to the molar ratio of tannic acid to zirconium oxychloride 1:1.2, first place a 2.0 wt% tannic acid solution in a constant temperature water bath and preheat it to 60℃, then add a 3.0 wt% zirconium oxychloride solution dropwise to the tannic acid solution at a rate of 2.5 mL / s, and stir the reaction at 60℃ and 400 rpm for 3.0 h; after the reaction is completed, cool to room temperature to obtain the tannic acid-zirconium coordination oligomer solution.

[0055] Plant-derived wax esters are composed of jojoba oil and rice bran wax in a mass ratio of 3:1.

[0056] A method for preparing abrasion-resistant and antibacterial composite leather for electronic skin includes the following steps: S1. Add plant polyphenols and glutaraldehyde to the delimed bare leather and tan at 35°C for 4 hours to obtain primary cross-linked raw leather. S2. The pH of the primary cross-linked raw leather was adjusted to 6.5 using a 3wt% acetic acid solution. Lysine-chitosan graft and tannic acid-zirconium coordination oligomer solution were added and reacted at 40°C for 3 hours to obtain antibacterial mineralized raw leather. S3. Plant-derived wax esters and lipase with an enzyme activity of 30,000 U / g were added to the antibacterial mineralized raw leather, and an enzyme-catalyzed transesterification reaction was carried out at 50°C for 60 min to obtain lubricated raw leather. S4. The lubricated raw leather is dried with hot air at 60°C to a moisture content of 15%, then rehydrated with deionized water to a moisture content of 25%, and then softened by tumbling at 35°C and 30 rpm for 60 minutes to obtain a wear-resistant and antibacterial composite leather for electronic skin with a thickness of 0.3 mm.

[0057] Comparative Example 1 A wear-resistant and antibacterial composite leather for electronic skin comprises the following raw materials in parts by weight: 110 parts of de-ashed bare leather, 1.4 parts of glutaraldehyde, 4 parts of lysine-chitosan graft, 3 parts of tannic acid-zirconium coordination oligomer solution, 4 parts of plant-derived wax ester, and 0.2 parts of lipase.

[0058] The specific preparation method for de-ashed raw hide is as follows: Take fresh cowhide, remove the hair mechanically, and then immerse it in a biological degreasing agent (composed of soybean lecithin, Tween 80, and deionized water in a mass ratio of 2.5:1:100) at a mass ratio of 1:35. Degrease at 35°C for 45 minutes, and wash three times with deionized water. Then, immerse it in a de-ashing solution (composed of ammonium chloride, fatty alcohol polyoxyethylene ether, and deionized water in a mass ratio of 1.5:0.3:100) at a mass ratio of 1:40 at a temperature of 30°C and a pH of 9, and stir at 400 rpm to remove ash. The ash was removed and washed three times with deionized water for 70 minutes. Then, it was immersed in an enzyme softening agent (composed of trypsin, lipase and deionized water in a mass ratio of 1:1.2:100, with trypsin activity of 4000 U / g and lipase activity of 22000 U / g) at a mass ratio of 1:25, softened at 32°C for 30 minutes, and washed three times with deionized water. Finally, it was freeze-dried to constant weight at -55°C and a vacuum degree of 10 Pa to obtain a deashed bare skin with a thickness of 0.3 mm and a water vapor permeability of 1100 g / (m²·24h).

[0059] The specific preparation method of lysine-chitosan graft is as follows: Chitosan is dissolved in a 1.5% (w / w) acetic acid solution to prepare a 1% (w / w) chitosan solution; EDC·HCl and NHS are added to the chitosan solution at a mass ratio of 1.6:0.45:125, and activated at 27°C for 45 min to obtain an activated solution; 7.5 wt% lysine solution is added dropwise to the activated solution at a rate of 2.5 mL / s at a molar ratio of chitosan to lysine of 1:1.2, and the mixture is stirred at 300 rpm for 9 h at room temperature. After the reaction is completed, the reaction solution is placed in a dialysis bag with a molecular weight cutoff of 4000 Da and dialyzed with deionized water for 36 h, with the deionized water being replaced every 7 h. Finally, the mixture is freeze-dried at -55°C and a vacuum of 10 Pa to constant weight to obtain the lysine-chitosan graft.

[0060] The specific preparation method of the tannic acid-zirconium coordination oligomer solution is as follows: according to the molar ratio of tannic acid to zirconium oxychloride 1:1, first place a 1.5wt% tannic acid solution in a constant temperature water bath and preheat it to 50℃, then add a 2.0wt% zirconium oxychloride solution dropwise to the tannic acid solution at a rate of 2.5mL / s, and stir the reaction at 50℃ and 300rpm for 2h; after the reaction is completed, cool to room temperature to obtain the tannic acid-zirconium coordination oligomer solution.

[0061] Plant-derived wax esters are composed of jojoba oil and rice bran wax in a mass ratio of 2.5:1.

[0062] A method for preparing abrasion-resistant and antibacterial composite leather for electronic skin includes the following steps: S1. Add glutaraldehyde to the delimed bare leather and tan it at 30°C for 3 hours to obtain primary cross-linked raw leather; S2. The pH of the primary cross-linked raw leather was adjusted to 6 using a 2wt% acetic acid solution. Lysine-chitosan graft and tannic acid-zirconium coordination oligomer solution were added and reacted at 37°C for 2.5 h to obtain antibacterial mineralized raw leather. S3. Plant-derived wax esters and lipase with an enzyme activity of 20000 U / g were added to the antibacterial mineralized raw leather, and an enzyme-catalyzed transesterification reaction was carried out at 47°C for 45 min to obtain lubricated raw leather. S4. The lubricated raw leather is dried with hot air at 55°C to a moisture content of 12%, then rehydrated with deionized water to a moisture content of 22%, and then softened by tumbling at 30°C and 25 rpm for 45 minutes to obtain a wear-resistant and antibacterial composite leather for electronic skin with a thickness of 0.5 mm.

[0063] Comparative Example 2 A wear-resistant and antibacterial composite leather for electronic skin comprises the following raw materials in parts by weight: 110 parts of de-ashed bare leather, 10 parts of plant polyphenols, 1.4 parts of glutaraldehyde, 3 parts of tannic acid-zirconium coordination oligomer solution, 4 parts of plant-derived wax esters, and 0.2 parts of lipase.

[0064] The specific preparation method for de-ashed raw hide is as follows: Take fresh cowhide, remove the hair mechanically, and then immerse it in a biological degreasing agent (composed of soybean lecithin, Tween 80, and deionized water in a mass ratio of 2.5:1:100) at a mass ratio of 1:35. Degrease at 35°C for 45 minutes, and wash three times with deionized water. Then, immerse it in a de-ashing solution (composed of ammonium chloride, fatty alcohol polyoxyethylene ether, and deionized water in a mass ratio of 1.5:0.3:100) at a mass ratio of 1:40 at a temperature of 30°C and a pH of 9, and stir at 400 rpm to remove ash. The ash was removed and washed three times with deionized water for 70 minutes. Then, it was immersed in an enzyme softening agent (composed of trypsin, lipase and deionized water in a mass ratio of 1:1.2:100, with trypsin activity of 4000 U / g and lipase activity of 22000 U / g) at a mass ratio of 1:25, softened at 32°C for 30 minutes, and washed three times with deionized water. Finally, it was freeze-dried to constant weight at -55°C and a vacuum degree of 10 Pa to obtain a deashed bare skin with a thickness of 0.3 mm and a water vapor permeability of 1100 g / (m²·24h).

[0065] Plant polyphenols are composed of taratanine and tea polyphenols in a mass ratio of 1.5:1.

[0066] The specific preparation method of the tannic acid-zirconium coordination oligomer solution is as follows: according to the molar ratio of tannic acid to zirconium oxychloride 1:1, first place a 1.5wt% tannic acid solution in a constant temperature water bath and preheat it to 50℃, then add a 2.0wt% zirconium oxychloride solution dropwise to the tannic acid solution at a rate of 2.5mL / s, and stir the reaction at 50℃ and 300rpm for 2h; after the reaction is completed, cool to room temperature to obtain the tannic acid-zirconium coordination oligomer solution.

[0067] Plant-derived wax esters are composed of jojoba oil and rice bran wax in a mass ratio of 2.5:1.

[0068] A method for preparing abrasion-resistant and antibacterial composite leather for electronic skin includes the following steps: S1. Add plant polyphenols and glutaraldehyde to the delimed bare leather and tan at 30°C for 3 hours to obtain primary cross-linked raw leather. S2. The pH of the primary cross-linked raw leather was adjusted to 6 using a 2wt% acetic acid solution, and a tannic acid-zirconium coordination oligomer solution was added. The mixture was reacted at 37°C for 2.5 h to obtain antibacterial mineralized raw leather. S3. Plant-derived wax esters and lipase with an enzyme activity of 20000 U / g were added to the antibacterial mineralized raw leather, and an enzyme-catalyzed transesterification reaction was carried out at 47°C for 45 min to obtain lubricated raw leather. S4. The lubricated raw leather is dried with hot air at 55°C to a moisture content of 12%, then rehydrated with deionized water to a moisture content of 22%, and then softened by tumbling at 30°C and 25 rpm for 45 minutes to obtain a wear-resistant and antibacterial composite leather for electronic skin with a thickness of 0.5 mm.

[0069] Comparative Example 3 A wear-resistant and antibacterial composite leather for electronic skin comprises the following raw materials in parts by weight: 110 parts of de-ashed bare leather, 10 parts of plant polyphenols, 1.4 parts of glutaraldehyde, 4 parts of lysine-chitosan graft, 4 parts of plant-derived wax ester, and 0.2 parts of lipase.

[0070] The specific preparation method for de-ashed raw hide is as follows: Take fresh cowhide, remove the hair mechanically, and then immerse it in a biological degreasing agent (composed of soybean lecithin, Tween 80, and deionized water in a mass ratio of 2.5:1:100) at a mass ratio of 1:35. Degrease at 35°C for 45 minutes, and wash three times with deionized water. Then, immerse it in a de-ashing solution (composed of ammonium chloride, fatty alcohol polyoxyethylene ether, and deionized water in a mass ratio of 1.5:0.3:100) at a mass ratio of 1:40 at a temperature of 30°C and a pH of 9, and stir at 400 rpm to remove ash. The ash was removed and washed three times with deionized water for 70 minutes. Then, it was immersed in an enzyme softening agent (composed of trypsin, lipase and deionized water in a mass ratio of 1:1.2:100, with trypsin activity of 4000 U / g and lipase activity of 22000 U / g) at a mass ratio of 1:25, softened at 32°C for 30 minutes, and washed three times with deionized water. Finally, it was freeze-dried to constant weight at -55°C and a vacuum degree of 10 Pa to obtain a deashed bare skin with a thickness of 0.3 mm and a water vapor permeability of 1100 g / (m²·24h).

[0071] Plant polyphenols are composed of taratanine and tea polyphenols in a mass ratio of 1.5:1.

[0072] The specific preparation method of lysine-chitosan graft is as follows: Chitosan is dissolved in a 1.5% (w / w) acetic acid solution to prepare a 1% (w / w) chitosan solution; EDC·HCl and NHS are added to the chitosan solution at a mass ratio of 1.6:0.45:125, and activated at 27°C for 45 min to obtain an activated solution; 7.5 wt% lysine solution is added dropwise to the activated solution at a rate of 2.5 mL / s at a molar ratio of chitosan to lysine of 1:1.2, and the mixture is stirred at 300 rpm for 9 h at room temperature. After the reaction is completed, the reaction solution is placed in a dialysis bag with a molecular weight cutoff of 4000 Da and dialyzed with deionized water for 36 h, with the deionized water being replaced every 7 h. Finally, the mixture is freeze-dried at -55°C and a vacuum of 10 Pa to constant weight to obtain the lysine-chitosan graft.

[0073] Plant-derived wax esters are composed of jojoba oil and rice bran wax in a mass ratio of 2.5:1.

[0074] A method for preparing abrasion-resistant and antibacterial composite leather for electronic skin includes the following steps: S1. Add plant polyphenols and glutaraldehyde to the delimed bare leather and tan at 30°C for 3 hours to obtain primary cross-linked raw leather. S2. The pH of the primary cross-linked raw leather was adjusted to 6 using a 2wt% acetic acid solution, and lysine-chitosan graft was added. The reaction was carried out at 37°C for 2.5 hours to obtain antibacterial mineralized raw leather. S3. Plant-derived wax esters and lipase with an enzyme activity of 20000 U / g were added to the antibacterial mineralized raw leather, and an enzyme-catalyzed transesterification reaction was carried out at 47°C for 45 min to obtain lubricated raw leather. S4. The lubricated raw leather is dried with hot air at 55°C to a moisture content of 12%, then rehydrated with deionized water to a moisture content of 22%, and then softened by tumbling at 30°C and 25 rpm for 45 minutes to obtain a wear-resistant and antibacterial composite leather for electronic skin with a thickness of 0.5 mm.

[0075] Comparative Example 4 A wear-resistant and antibacterial composite leather for electronic skin comprises the following raw materials in parts by weight: 110 parts of de-ashed bare leather, 10 parts of plant polyphenols, 1.4 parts of glutaraldehyde, 4 parts of lysine-chitosan graft, 3 parts of tannic acid-zirconium coordination oligomer solution, and 4 parts of plant-derived wax esters.

[0076] The specific preparation method for de-ashed raw hide is as follows: Take fresh cowhide, remove the hair mechanically, and then immerse it in a biological degreasing agent (composed of soybean lecithin, Tween 80, and deionized water in a mass ratio of 2.5:1:100) at a mass ratio of 1:35. Degrease at 35°C for 45 minutes, and wash three times with deionized water. Then, immerse it in a de-ashing solution (composed of ammonium chloride, fatty alcohol polyoxyethylene ether, and deionized water in a mass ratio of 1.5:0.3:100) at a mass ratio of 1:40 at a temperature of 30°C and a pH of 9, and stir at 400 rpm to remove ash. The ash was removed and washed three times with deionized water for 70 minutes. Then, it was immersed in an enzyme softening agent (composed of trypsin, lipase and deionized water in a mass ratio of 1:1.2:100, with trypsin activity of 4000 U / g and lipase activity of 22000 U / g) at a mass ratio of 1:25, softened at 32°C for 30 minutes, and washed three times with deionized water. Finally, it was freeze-dried to constant weight at -55°C and a vacuum degree of 10 Pa to obtain a deashed bare skin with a thickness of 0.3 mm and a water vapor permeability of 1100 g / (m²·24h).

[0077] Plant polyphenols are composed of taratanine and tea polyphenols in a mass ratio of 1.5:1.

[0078] The specific preparation method of lysine-chitosan graft is as follows: Chitosan is dissolved in a 1.5% (w / w) acetic acid solution to prepare a 1% (w / w) chitosan solution; EDC·HCl and NHS are added to the chitosan solution at a mass ratio of 1.6:0.45:125, and activated at 27°C for 45 min to obtain an activated solution; 7.5 wt% lysine solution is added dropwise to the activated solution at a rate of 2.5 mL / s at a molar ratio of chitosan to lysine of 1:1.2, and the mixture is stirred at 300 rpm for 9 h at room temperature. After the reaction is completed, the reaction solution is placed in a dialysis bag with a molecular weight cutoff of 4000 Da and dialyzed with deionized water for 36 h, with the deionized water being replaced every 7 h. Finally, the mixture is freeze-dried at -55°C and a vacuum of 10 Pa to constant weight to obtain the lysine-chitosan graft.

[0079] The specific preparation method of the tannic acid-zirconium coordination oligomer solution is as follows: according to the molar ratio of tannic acid to zirconium oxychloride 1:1, first place a 1.5wt% tannic acid solution in a constant temperature water bath and preheat it to 50℃, then add a 2.0wt% zirconium oxychloride solution dropwise to the tannic acid solution at a rate of 2.5mL / s, and stir the reaction at 50℃ and 300rpm for 2h; after the reaction is completed, cool to room temperature to obtain the tannic acid-zirconium coordination oligomer solution.

[0080] Plant-derived wax esters are composed of jojoba oil and rice bran wax in a mass ratio of 2.5:1.

[0081] A method for preparing abrasion-resistant and antibacterial composite leather for electronic skin includes the following steps: S1. Add plant polyphenols and glutaraldehyde to the delimed bare leather and tan at 30°C for 3 hours to obtain primary cross-linked raw leather. S2. The pH of the primary cross-linked raw leather was adjusted to 6 using a 2wt% acetic acid solution. Lysine-chitosan graft and tannic acid-zirconium coordination oligomer solution were added and reacted at 37°C for 2.5 h to obtain antibacterial mineralized raw leather. S3. Add plant-derived wax esters to antibacterial mineralized raw leather and place at 47°C for 45 minutes to obtain lubricated raw leather. S4. The lubricated raw leather is dried with hot air at 55°C to a moisture content of 12%, then rehydrated with deionized water to a moisture content of 22%, and then softened by tumbling at 30°C and 25 rpm for 45 minutes to obtain a wear-resistant and antibacterial composite leather for electronic skin with a thickness of 0.5 mm.

[0082] Performance verification This experiment aims to verify the core performance of wear-resistant and antibacterial composite leather for electronic skin. By comparing the wear resistance, antibacterial properties, breathability, and softness of Examples 1-3 and Comparative Examples 1-4, the effects of the composite tanning system, synergistic antibacterial system, and enzyme-catalyzed transesterification process on improving the overall performance of the leather are evaluated.

[0083] (1) Abrasion resistance test: According to QB / T 2726-2005 "Determination of abrasion resistance of leather physical and mechanical tests", composite leather samples prepared in Examples 1-3 and Comparative Examples 1-4 were cut into 50mm×50mm samples and tested with a Martindale abrasion tester. The load was set to 4.9N and the abrasive was standard fabric. The number of abrasions when obvious damage appeared on the sample surface was recorded to characterize the abrasion resistance of the leather.

[0084] (2) Antibacterial performance test: According to GB / T 20944.3-2008 "Evaluation of antibacterial properties of textiles - Part 3: Shaking method", Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 6538) were selected as test strains, and antibacterial tests were performed on the samples of Examples 1-3 and Comparative Examples 1-4, respectively. First, the 24-hour inhibition rate of the samples against the two strains was determined to evaluate the immediate antibacterial effect; then, the samples were immersed in artificial sweat at 37°C for 7 days to simulate the skin-contact environment, and the 72-hour inhibition rate of the samples against Escherichia coli after immersion was determined to evaluate the long-term antibacterial stability.

[0085] (3) Air permeability test: According to GB / T 1037-2021 "Determination of water vapor permeability of plastic films and sheets by cup weight gain and loss method", the samples of Examples 1-3 and Comparative Examples 1-4 were cut to the specified size, placed on a moisture permeability cup, and the test environment temperature was controlled at 38℃ and the relative humidity at 90%. The water vapor permeability of the samples was tested, and the unit was g / (m²・24h) to quantify the air permeability of the leather.

[0086] (4) Softness test: Using the professional hand feel scoring method, 5 experienced leather performance evaluators were selected to score the softness of the samples of Examples 1-3 and Comparative Examples 1-4 on a 5-point scale (scoring criteria: 5 points: extremely soft, fits the skin without any binding feeling; 4 points: soft, fits the skin without obvious binding feeling; 3 points: relatively soft, slight binding feeling; 2 points: slightly hard, with obvious binding feeling; 1 point: too hard, cannot fit the skin). The average score of the 5 evaluators was taken as the final softness score of the sample.

[0087] The core performance test results of Examples 1-3 and Comparative Examples 1-4 are shown in Table 1.

[0088] Table 1. Test Results of Core Performance of Composite Leather Conclusion: In terms of abrasion resistance, the abrasion resistance of Examples 1-3 all exceeded 18,000 cycles, with Example 2 showing the best performance at 19,800 cycles, significantly superior to the comparative samples. This advantage stems from the synergistic effect of the "plant polyphenols + glutaraldehyde" composite tanning system and the mineralization enhancement of tannic acid-zirconium coordination oligomers. The composite tanning system can construct a dense and stable cross-linked network between leather fibers, and the inorganic reinforcing phase formed by tannic acid-zirconium coordination oligomers further enhances the fiber structural strength. Together, they strengthen the abrasion-resistant base of the leather. In contrast, Comparative Example 1, lacking plant polyphenols and using only glutaraldehyde for tanning, had insufficient fiber cross-linking density, resulting in only 8,200 abrasion cycles, a decrease of 58.6% compared to Example 2. Comparative Example 4, without enzyme-catalyzed ester exchange, could not uniformly coat the fibers with plant-derived wax esters to form a lubricating protective layer, resulting in only 10,500 abrasion cycles, a decrease of 46.9% compared to Example 2. This fully demonstrates the key role of the composite tanning system and enzyme-catalyzed ester exchange process in improving abrasion resistance.

[0089] In terms of antibacterial performance, Examples 1-3 exhibited excellent immediate antibacterial effects and long-term stability, with 24-hour inhibition rates of ≥99.0% against Escherichia coli and Staphylococcus aureus. After 7 days of immersion in artificial sweat at 37°C, the inhibition rate against Escherichia coli remained above 98.7% for 72 hours. This is attributed to the synergistic antibacterial mechanism of "lysine-chitosan graft + tannic acid-zirconium coordination oligomer": the lysine-chitosan graft firmly anchors to the leather matrix with good substrate adhesion, achieving antibacterial effect by disrupting bacterial cell walls; the zirconium ions in the tannic acid-zirconium coordination oligomer can penetrate bacterial cell membranes and disrupt internal structures. The synergistic effect of the two significantly improves antibacterial efficiency and durability. The 24-hour antibacterial rates of Comparative Example 2 (retaining only tannic acid-zirconium coordination oligomer) and Comparative Example 3 (retaining only lysine-chitosan graft) were both below 94%, and the antibacterial rate further decreased to 85.3%-86.7% after sweat immersion. Their antibacterial long-term effect was significantly inferior to that of Examples 1-3, which confirmed the irreplaceable synergistic effect of the two antibacterial components. The antibacterial performance of Comparative Examples 1 and 4 was similar to that of Examples 1-3, indicating that the absence of the composite tanning system and the omission of the enzyme catalysis process had no significant negative impact on the antibacterial effect.

[0090] Regarding breathability and softness, the water vapor permeability of Examples 1-3 was ≥1050g / (m²・24h), and the softness score was ≥4.6 points, fully meeting the comfort requirements for electronic skin contact. This is due to the gentle de-ashed bare leather preparation process of this invention—the precisely controlled degreasing and softening conditions maximize the preservation of the natural porous structure of the leather fibers, laying the foundation for breathability; at the same time, the plant-derived wax esters can be uniformly dispersed and coated on the fibers after enzyme-catalyzed ester exchange, effectively improving the softness of the leather. Comparative Example 4, lacking lipase, did not undergo enzyme-catalyzed ester exchange, and the plant-derived wax esters were prone to agglomeration, resulting in a softness score of only 3.2 points, a decrease of 33.3% compared to Example 2, highlighting the necessity of the enzyme-catalyzed ester exchange process for ensuring softness; although the water vapor permeability of each comparative example was slightly lower than that of Examples 1-3, it remained above 970g / (m²・24h), indicating that the adjustment of the core components and optimization of the process of this invention will not damage the breathable structure of the leather and can better preserve the inherent breathability advantages of the substrate.

[0091] In summary, the wear-resistant and antibacterial composite leather for electronic skin prepared in Examples 1-3 achieves synergistic optimization in four core properties: wear resistance, antibacterial properties, breathability, and softness. Its overall performance is significantly superior to that of Comparative Examples 1-4, which lack key components or have altered core processes. This invention, through a multi-system synergistic design of "composite tanning - synergistic antibacterial - enzyme-catalyzed lubrication," solves the pain points of insufficient wear resistance, poor long-term antibacterial effect, and unsatisfactory softness in existing leather skin applications. Each key component and process works synergistically and is indispensable, fully demonstrating the inventiveness and practicality of this invention, especially suitable for the field of electronic skin where stringent comprehensive performance requirements are necessary.

[0092] The above specific embodiments are merely explanations of the present invention and are not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to these embodiments without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A wear-resistant and antibacterial composite leather for electronic skin, characterized in that, The raw materials include the following parts by weight: 100-120 parts of delimed bare bark, 5-15 parts of plant polyphenols, 0.8-2.0 parts of glutaraldehyde, 2-6 parts of lysine-chitosan graft, 1-5 parts of tannic acid-zirconium coordination oligomer solution, 2-6 parts of plant-derived wax esters, and 0.1-0.3 parts of lipase.

2. The wear-resistant and antibacterial composite leather for electronic skin according to claim 1, characterized in that, The method for preparing the deashed naked skin is as follows: take fresh animal skin, remove the hair, immerse it in a biological degreasing agent to degrease, and wash it; then immerse it in a deashing solution to stir and deash it, and wash it; then immerse it in an enzyme softening agent to soften it, and wash it; finally, freeze dry it under vacuum to obtain the deashed naked skin.

3. The wear-resistant and antibacterial composite leather for electronic skin according to claim 1, characterized in that, The plant polyphenols are composed of taratanine and tea polyphenols in a mass ratio of 1-2:

1.

4. The wear-resistant and antibacterial composite leather for electronic skin according to claim 1, characterized in that, The preparation method of the lysine-chitosan graft is as follows: chitosan is dissolved in acetic acid solution, activated by adding EDC·HCl and NHS, lysine solution is added dropwise, the reaction is stirred at room temperature, dialyzed and freeze-dried to obtain the lysine-chitosan graft.

5. The wear-resistant and antibacterial composite leather for electronic skin according to claim 1, characterized in that, The method for preparing the tannic acid-zirconium coordination oligomer solution is as follows: add zirconium oxychloride solution dropwise to tannic acid solution, heat and stir to react, and then cool to obtain the tannic acid-zirconium coordination oligomer solution.

6. The wear-resistant and antibacterial composite leather for electronic skin according to claim 1, characterized in that, The plant-derived wax ester is composed of jojoba oil and rice bran wax in a mass ratio of 2-3:

1.

7. The wear-resistant and antibacterial composite leather for electronic skin according to claim 1, characterized in that, The lipase has an enzyme activity of 10,000-30,000 U / g.

8. A method for preparing abrasion-resistant and antibacterial composite leather for electronic skin according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Plant polyphenols and glutaraldehyde are added to delimed bare leather and tanned to obtain primary cross-linked raw leather; S2. Adjust the pH of the primary cross-linked raw leather to 5.5-6.5, add lysine-chitosan graft and tannic acid-zirconium coordination oligomer solution, and react at 35-40°C for 2-3 hours to obtain antibacterial mineralized raw leather. S3. Plant-derived wax esters and lipases are added to antibacterial mineralized raw leather to carry out an enzyme-catalyzed transesterification reaction to obtain lubricated raw leather. S4. Dry, rehydrate, and soften the lubricated raw leather to obtain wear-resistant and antibacterial composite leather for electronic skin with a thickness of 0.3-0.8mm.

9. The method for preparing wear-resistant and antibacterial composite leather for electronic skin according to claim 8, characterized in that, In step S1, the tanning temperature is 25-35°C and the tanning time is 2-4 hours.

10. The method for preparing wear-resistant and antibacterial composite leather for electronic skin according to claim 8, characterized in that, In step S3, the temperature of the enzyme-catalyzed transesterification reaction is 45-50°C, and the reaction time is 30-60 min.

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