Low-carbon preparation method of antibacterial ecological leather based on all-natural materials

Abstract

This invention relates to a low-carbon preparation method for antibacterial eco-leather based on all-natural materials, comprising the following steps: batching → pre-soaking → fleshing and trimming → main soaking → fleshing and trimming → enzymatic hair removal → liming → splitting and trimming → deliming → softening → acid soaking → tanning with yellow collagen aldehyde-aluminum combined → standing, squeezing, and smoothing → rewetting → neutralization → filling with waste leather collagen modifiers and dyeing with plant dyes → fatliquoring with modified rapeseed oil → dyeing with plant dyes → drying and finishing → vanillin finishing. The innovative feature of this invention is the use of a yellow collagen aldehyde-Al(III) combined tanning process, resulting in a leather shrinkage temperature ≥90℃, far exceeding the industry standard (≥75℃); an antibacterial rate >99% against Staphylococcus aureus, Klebsiella pneumoniae, and Candida albicans; a tear strength of 62N, a bursting force of 220N, and a bursting height of 9mm, exhibiting high mechanical strength and good structural stability.

Description

Technical Field

[0001] This invention relates to the field of leather manufacturing technology, and in particular to a low-carbon method for preparing antibacterial eco-leather based on all-natural materials. Background Technology

[0002] Leather is a modified, rot-resistant material obtained by processing animal hides through physical and chemical processes such as hair removal and tanning. It is composed of natural protein fibers tightly woven in three-dimensional space, with a special grain layer on the surface. It has natural grain, luster and a comfortable feel, and also has high strength, good breathability and abrasion resistance. Therefore, it is widely used in clothing, footwear, bags, automotive interiors, furniture and many other fields.

[0003] Traditional leather tanning processes use a large amount of chrome tanning, petroleum-based chemicals, and high-VOC coating agents, resulting in problems such as heavy metal pollution, high energy consumption, large carbon emissions, non-degradability, poor antibacterial and mildew resistance, low comfort, and residual odor.

[0004] Existing chromium-free tanning processes (aluminum tanning, zirconium tanning, vegetable tanning) suffer from low shrinkage temperature, poor stability, insufficient filling, low strength, weak antibacterial properties, and susceptibility to mold. Existing bio-based coatings have low antibacterial efficiency, poor long-term effectiveness, no photothermal response, insufficient breathability, and weak mechanical properties. Existing low-carbon processes have not achieved closed-loop raw material production, have low waste utilization rates, and incomplete antibacterial systems, making it difficult to simultaneously meet the comprehensive requirements of being all-natural, low-carbon, chromium-free, highly comfortable, long-lasting antibacterial and anti-mildew, and biodegradable.

[0005] Therefore, there is an urgent need to develop an eco-friendly leather manufacturing process that uses all-natural raw materials, is low-carbon and closed-loop, is chromium-free tanned, is bio-based and functionalized, has long-lasting antibacterial properties in response to light and heat, is highly comfortable, and is industrially feasible. Summary of the Invention

[0006] This invention provides a low-carbon manufacturing process for antibacterial eco-leather made from all-natural materials to address the aforementioned deficiencies.

[0007] The present invention adopts the following technical solution: A low-carbon preparation method for antibacterial eco-leather based on all-natural materials includes the following steps: batching → pre-soaking → fleshing and trimming → main soaking → fleshing and trimming → enzymatic hair removal → liming → splitting and trimming → deliming → softening → acid soaking → tanning with yellow collagen aldehyde-aluminum combination → standing, squeezing out water, and shaving evenly → rewetting → neutralization → filling with waste leather collagen modifiers and dyeing with plant dyes → fatliquoring with modified rapeseed oil → dyeing with plant dyes → drying and finishing → vanillin finishing; in, Batching: Using wet cowhide as raw material, weigh it and add 150% to the weight for measurement; Pre-soaking: Place the batched salted beef hides into a drum, add 180-200% water at 18-20℃, 0.2-0.3% probiotic penetrant, 0.3-0.5% probiotic soaking agent, 0.1-0.2% probiotic defatting agent, and 0.5-1.5% wood ash. Rotate for 10 minutes, stop for 20 minutes; repeat 2-3 times; rotation speed 2-3 rpm; control temperature 19-21℃, pH 6.3-6.7, Baume degree 8-9; repeat 4-6 times; wash with water, remove from the drum; remove meat and trim edges; weigh, and add 150% weight for measurement; Preparation of the above-mentioned plant ash: Burn waste wood and residues from natural plant materials produced by this patented technology, collect the combustion ash, crush it, pour the plant ash into water, stir, filter out impurities, and that is the plant ash solution. Soaking: Place the pre-soaked, de-fleshed, and trimmed cowhide into a drum, add 80-150% water at 18-22℃, and rotate the drum at 3 rpm; add 0.2-0.4% probiotic soaking agent, 0.2-0.4% probiotic penetrant, and 0.1-0.2% probiotic defatting agent, rotate for 10 minutes, then stop for 20 minutes; control the pH at 6.3-6.7, rotate the drum at 2-3 rpm, and repeat 1-3 times; add 0.5-1.5% wood ash and 0.4-0.6% plant fungicide, adjust the pH to 9.5-10.5, rotate for 10 minutes, then stop for 20 minutes; repeat 5-8 times until fully saturated and the cut is milky white; wash with water, remove from the drum; de-fleshed and trim; weigh, and add 150% weight for measurement; Preparation of the above-mentioned plant fungicide: 1 kg of dried and pulverized plant powder (such as camphor leaves, tea leaves, licorice, etc.) is added to a subcritical treatment device, 10-15 kg of 30-90% ethanol aqueous solution is added, the device is sealed, and the reaction is carried out at a temperature of 100-150℃ and a pressure of 0.5-1.5 MPa for 0.5-3 hours. The mixture is filtered, the filtrate is collected, and the solution is concentrated by rotary evaporation to obtain the plant fungicide. Enzymatic hair removal: The soaked cowhide, after primary soaking, fleshing, and trimming, is placed in a rotating drum. 100% chlorine solution at 24-28℃ is added, and the drum speed is 6-8 rpm. The pH is adjusted to 9.0-9.5. 0.3% probiotic penetrant, 1.0-1.5% nano-negative ion powder, and 0.7-1.3% compound enzyme (patent: ZL201510347968.6) are added, and the drum is rotated for 30 minutes. 0.3-0.5% keratinase is added, and the drum is rotated for another 30 minutes. The hair removal rate is checked. If the hair removal rate is greater than 90%, proceed to the next step; otherwise, continue rotating for 30-60 minutes. The hide is then washed, filtered, and drained. Lime treatment: Place the de-limed bovine hides (with a hair removal rate >90%) into a drum, add 100% water at 24-26℃, and rotate the drum at 3-5 rpm; add 0.3% probiotic penetrant and 2% lime, and rotate for 60 minutes; add 100% water at 24-26℃, 50% of a 15-25% wood ash solution, and 0.15-0.2% of a 30% sodium hydroxide solution, and rotate for 60 minutes; then rotate for 5 minutes, stop for 55 minutes, and repeat 5-8 times; wash with water, remove from the drum; remove meat, trim edges, and split layers; weigh, and add 150% weight for measurement. De-ashing: Place the de-fleshed, trimmed, and split cowhide into a drum, add 30-60% water at 30-35℃, 0.3% probiotic penetrant, and 1.0-2.0% citric acid (food grade, Rizhao Jinhe Biochemical Group Co., Ltd.), and rotate for 30-60 minutes at 6 rpm; then add 1.0-3.0% citric acid and rotate for 90-180 minutes. Softening: Continue adding 1.0-3.5% acidic softening enzyme (TJ-A489) and 0.3% probiotic defatting agent, incubate for 10 minutes, then stop for 20 minutes; adjust the temperature to 30-32℃ and pH to 7.5-8.5, incubate for 10 minutes, then stop for 20 minutes; repeat 2-3 times. When the buttock incision shows no color change in phenolphthalein reagent, softening is considered complete; wash with water and remove from the drum; Acid soaking: Put the softened bare skin into a rotating drum, add 50-60% water at 20-22℃, add 7-10% salt, and rotate for 5-15 minutes; add 0.5-1.5% diluted citric acid and 0.5-1.5% sulfuric acid, adjust the pH to 2.8-3.0, and rotate for 30-90 minutes; Xanthan gum aldehyde-Al(III) combined tanning: Continue adding 140-160% water at 20-22℃ and 3-5% salt, and rotate for 5-15 minutes; add 6-10% xanthan gum aldehyde and rotate for 180-300 minutes; add 0.5-1.5% wood ash every 15-20 minutes to adjust the pH to 7.5-8.5, maintain the temperature at 38-42℃, and rotate for 180-300 minutes; wash with water, remove from the drum and let stand for 24 hours; then put it back into the drum, add 180-230% water at 38-42℃ and 2-3% citric acid, and rotate for 30-60 minutes; add 8-12% aluminum sulfate and rotate for 180-300 minutes; add 0.5-1.5% wood ash every 15-20 minutes to adjust the pH to 7.5-8.5, maintain the temperature at 38-42℃, and rotate for 180-300 minutes; wash with water, remove from the drum and let stand for more than 24 hours; obtain white wet leather; Preparation of the above-mentioned yellow collagen aldehyde: Add 1 kg of yellow collagen and 25 L of water to a light-proof reaction vessel and stir for 8-24 h; add 0.5-0.8 kg of sodium periodate, adjust the temperature to 8-12℃, and react for 12-36 h; add 0.1-0.3 kg of sucrose and react for 60-120 min; adjust the pH to 6.3-6.6; vacuum filter, and freeze-dry the filtrate to obtain yellow collagen aldehyde; Rehydration: Place the combined-tanned white wet leather into a drum, add 300-400% water at 38-42℃, 0.1-0.3% probiotic penetrant, 0.1-0.3% probiotic degreasing agent, and 1-3% citric acid; rotate for 30-60 minutes; drain and dry. Neutralization: Place the rehydrated white wet leather into a drum, add 300-400% water at 38-42℃, 0.2-0.4% probiotic penetrant, 0.5-1.5% sodium citrate, and 0.5-1.5% wood ash, and rotate for 30-90 minutes; add 0.5-1.5% wood ash to adjust the pH to 5.8-6.2; drain and allow to dry. Filling: Place the neutralized wet white leather into a drum, add 100-150% water at 30-40℃, 1-2% sulfite fish oil (MIR-90, Yixiang Chemical), 4-6% chamomile bark tannin (ME, Shihua Technology), 4-6% arborvitae tannin (ATO, Shihua Technology), and 2-3% plant dye, and rotate for 120-180 minutes; add 4-6% waste leather collagen modifier, and rotate for 60-120 minutes; adjust the pH to 4.0 with citric acid, and rotate for 15-30 minutes; drain and dry. Preparation of plant dyes: 1 kg of dried and pulverized plant powder (such as Sophora japonica, turmeric, Polygonum tinctorium, safflower, gardenia, dragon fruit, etc.) is added to a subcritical fluid processing device, along with 10-15 kg of a 5-50% ethanol aqueous solution. The device is sealed and reacted at 100-150℃ and 0.5-1.5 MPa for 0.5-3 hours. After filtration, the filtrate is collected and concentrated by rotary evaporation to obtain the plant dye. Preparation of modified waste leather collagen: Add 1 kg of chromium-free tanning waste (such as trimming scraps, shavings, etc.) to a reactor, along with 10-15 L of water and 50-100 mL of copper-iron catalyst. Adjust the temperature to 70-75℃ and react for 5-15 min. Add 0.8-1.2 kg of hydrogen peroxide and 10-30 g of sulfuric acid, and react for 60-120 min. Filter the solution, and freeze-dry the filtrate to obtain leather collagen. Continue adding 1 kg of leather collagen and 10-15 L of water to the reactor, adjust the pH to 7.5-8.0 with sodium hydroxide, add 2-10% sodium alginate, adjust the temperature to 55-65℃, and react for 120-180 min. Freeze-dry the mixture to obtain the modified waste leather collagen. Modified rapeseed oil fatliquoring: Place the filled wet white leather into a rotating drum, add 150-200% water (50-60℃), 9-15% modified rapeseed oil fatliquoring agent, adjust the temperature to 50-60℃, and rotate for 60-90 minutes; add 0.1-0.8% citric acid every 15-20 minutes to adjust the pH to 3.6-4.0; wash with water, drain, and dry. Preparation of modified rapeseed oil fatliquoring agent: Add 1 kg of rapeseed oil and 10-20 g of magnesium oxide to a reaction vessel, purge with nitrogen, adjust the temperature to 160-180℃ and the pressure to 0.3-0.4 MPa, slowly introduce 100-200 g of ethylene oxide, and react for 8-12 hours; then sulfonate using an SO3 falling film sulfonation device for 30-150 minutes, controlling the SO2 flow rate at 0.6-1.0 L / min, the air flow rate at 18-20 L / min, and the cooling jacket temperature at 70-75℃ during sulfonation to obtain ethoxylated modified sulfonated rapeseed oil; then mix 1 kg of ethoxylated modified sulfonated rapeseed oil, 0.2-0.3 kg of probiotic permeation solution, 0.1-0.2 kg of water, 40-50 g of surfactant, and 30-50 g of organosilicon defoamer evenly, adjust the pH to 7.5-8.0, and obtain the modified rapeseed oil fatliquoring agent. Dyeing: Place the fattened white wet leather into a drum, add 150-200% water at 55-60℃ and 1-2% zeolite tanning agent, and rotate for 30-60 minutes; then add 0.5-2.0% plant dye and rotate for 30-60 minutes; add 0.5-2.0% citric acid at 15-20 minutes intervals to adjust the pH to 3.3-3.6, and rotate for 15-20 minutes; add 1-2% zeolite tanning agent and rotate for 15-20 minutes; add 0.5-2.0% GS sulfite fish oil (MIR-90, Yixiang Chemical) evenly dispersed in 5 times its volume of water at 55℃, and rotate for 15-20 minutes; wash with water, drain, and dry.

[0008] Furthermore, the above finishing process is as follows: water squeezing and stretching → vacuum drying → hanging drying → re-moistening → softening by tumbling → stretching and drying → sealing the base → troweling → top coating → softening → rolling → measuring and warehousing; the main operational points are as follows: Dewatering and stretching: Performed on a reciprocating dewatering and stretching machine with a blade spacing of 1.10-1.15 mm, a dewatering pressure of 30 bar, and a feed speed of 20-25 m / min; the moisture content after dewatering is controlled at 50-55%. Vacuum drying: carried out in a vacuum dryer at a temperature of 45℃ for 500 seconds, with a negative pressure of 23-26 Mbar; the moisture content after vacuum drying is controlled at 23-30%. Hanging and drying: carried out on a hanging drying line, with a hanging time of 24 hours. After hanging and drying, the moisture content is controlled at 13-18%. Rehydration: Performed on a rehydration machine, the moisture content is controlled at 20-25% after rehydration; Tumbling and softening: This is carried out in a stainless steel octagonal tumbling and softening drum at a speed of 15 r / min for 6 hours. The drum rotates in both directions, and the internal temperature is automatically controlled at 25-30℃. After tumbling and softening, the moisture content of the raw leather is 18-20%. Stretching: Performed on a horizontal stretching machine, oven temperature 50℃, stretching distance 6cm, clamping distance 10-12cm, raw leather time in oven 20min, raw leather moisture content 14%-18%; Base coat: Operate on a spraying machine, with a coating amount of approximately 5-10 g / sf, spraying 1-3 times, each time 3-5 g / sf2, with a coating amount of approximately 3-15 g / sf2; the coating agent formula is as follows: 400-800 parts water, 100-200 parts negative ion aqueous solution (VEIKEKJP39, Hunan Kangjian Nanomaterials Technology Co., Ltd.); 500-800 parts water-soluble protein binder, 200-300 parts modified protein and modified protein gloss agent, 20-100 parts probiotic penetrant; 50-100 parts bio-based additives; Calendering: Performed on a board ironing machine at a board surface temperature of 100℃, a pressure of 30kg, and a time of 2s. Top coat: Operate on a computer-controlled sprayer, spray 2-3 times, each time 3-5g / sf2, with a coating amount of about 9-15g / sf2; Oscillating softening: Operated on an oscillating softening machine with the following parameters: conveying speed 9.5m / min, number of stages 5; Blazing: Operated on a pass-through ironing machine, with a temperature of 120℃, a pressure of 20-30kg, and a speed of 8m / min.

[0009] Furthermore, the above coating agent formulation is as follows: 100-300 parts water, 200-300 parts P(MMA-BA-DV) emulsion, 1.5-2.5 parts EG@MXene / Ag-MOF composite nanofiller, 20-100 parts penetrant, and 50-100 parts bio-based additives; Wherein: DV is double-bonded vanillin, which is formed by introducing a methacrylic acid double bond through Steglich esterification of vanillin; MXene is Ti3C2T X It is prepared by etching Ti3AlC2 with LiF / HCl, ultrasonic exfoliation and freeze drying; Ag-MOF is Ag-BTC, which is grown in situ on the surface of MXene; EG is eugenol, which is impregnated and encapsulated in the porous structure of MXene / Ag-MOF with an encapsulation rate of ≥15%; P(MMA-BA-DV) is methyl methacrylate-butyl acrylate-double-bonded vanillin terpolymer emulsion.

[0010] Furthermore, the preparation of the above formula includes the following steps: Step 1, Preparation of double-bonded vanillin (DV): Vanillin and methacrylic acid were esterified by Steglich reaction at room temperature for 6-12 h under DCC / DMAP catalysis; filtered, recrystallized, and vacuum dried to obtain DV; Step 2, Preparation of MXene / Ag-MOF: 1 g Ti3AlC2, 0.6-1.0 g LiF, 20 mL 36% HCl, stirred at 35-40℃ for 48 h; centrifuged, washed with water until pH≈6, ultrasonically exfoliated (30 min, 300 W), and freeze-dried to obtain MXene powder; 0.1 g MXene was dispersed in 30 mL water and ultrasonicated for 10 min; 0.0849 g AgNO3 and 0.1051 g H3BTC were added, stirred at room temperature for 2 h, and allowed to stand for 12 h; centrifuged and dried to obtain MXene / Ag-MOF composite powder; Step 3, Preparation of EG@MXene / Ag-MOF: MXene / Ag-MOF and eugenol (EG) were mixed at a mass ratio of 3:1 and impregnated with ethanol for 24 hours; centrifuged and vacuum dried to obtain EG@MXene / Ag-MOF; the encapsulation efficiency was approximately 16%. Step 4, Preparation of P(MMA-BA-DV) emulsion: Aqueous phase: SDS 0.28g, n-butanol 0.40g, deionized water 30g; Oil phase: MMA, BA, DV mixed in a mass ratio of 6:3:1; The oil and water mixture was sonicated for 15min to obtain a pre-microemulsion; At 75℃, KPS 0.15g (13mL water) was added first, and after 2h, KPS 0.45g (23.5mL water) was added to the pre-microemulsion; The reaction was continued for 2h, cooled, and filtered to obtain the P(MMA-BA-DV) emulsion; Step 5, preparation of composite coating agent: 1.0 g of EG@MXene / Ag-MOF is dispersed in 10 mL of water and sonicated for 30 min; 100 g of P(MMA-BA-DV) emulsion is slowly added and stirred at room temperature for 4 h; After filtration and adjustment of the solids content to 20%–30%, a topcoat finishing agent is obtained.

[0011] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following advantages: 1. All raw materials and auxiliaries of this invention are derived from natural / bio-based sources. They utilize wood ash, waste leather collagen, and plant residues for recycling, achieving a closed-loop waste management system. The entire tanning process is chromium-free and has low VOC emissions. The biochar content of the leather is >90%, significantly reducing the carbon footprint and meeting the needs of "dual carbon" development. There is no pollution from heavy metals, residual solvents, harmful dyes, or other harmful substances.

[0012] 2. The innovation of this invention adopts the yellow collagen aldehyde-Al(III) combined tanning process, the leather shrinkage temperature is ≥90℃, far exceeding the industry standard (≥75℃); the tearing force reaches 62N, the bursting force is 220N, and the bursting height is 9mm. It has high mechanical strength and good structural stability, and completely solves the pain points of traditional chrome-free tanning, such as low shrinkage temperature, poor stability and insufficient strength.

[0013] 3. The integrated bio-based photothermal responsive antibacterial coating technology of the present invention prepares a P(MMA-BA-DV)-EG@MXene / Ag-MOF composite coating layer with an antibacterial rate of ≥99%, a mildew resistance rate of 100%, and an antibacterial long-term effect of ≥30 days; effectively solving the problems of low antibacterial efficiency, poor long-term effect, and easy mildew in traditional leather, and improving the hygiene and safety of products.

[0014] 4. The present invention employs plant dyeing, modified rapeseed oil fatliquoring, and bio-based filling processes, resulting in leather with high softness, excellent breathability and moisture permeability (water permeability reaches 15.2mg / cm²•h); dry / wet rubbing color fastness of 4-5 grade, coating folding fastness of 50,000 cycles without cracking, strong weather resistance and durability, and a balance between comfort and practicality.

[0015] 5. The finished leather of this invention fully meets the Class A standard of the Green Design Product Evaluation Technical Specification for Leather. The formaldehyde content is only 12.5mg / kg (≤20mg / kg). Volatile organic compounds, alkylphenols, organotin compounds, heavy metals, carcinogenic dyes and other harmful substances were not detected. There is no chromium and the hexavalent chromium residue is extremely low. It can be safely used in many fields such as shoes, bags, furniture, and automotive interiors. Detailed Implementation

[0016] Example 1: A low-carbon preparation method for antibacterial eco-leather based on all-natural materials includes the following steps: batching → pre-soaking → fleshing and trimming → main soaking → fleshing and trimming → enzymatic hair removal → liming → splitting and trimming → deliming → softening → acid soaking → tanning with yellow collagen aldehyde-aluminum combination → standing, squeezing out water, and shaving evenly → rewetting → neutralization → filling with waste leather collagen modifiers and dyeing with plant dyes → fatliquoring with modified rapeseed oil → dyeing with plant dyes → drying and finishing → vanillin finishing; in, Batching: Using wet cowhide as raw material, weigh it and add 150% to the weight for measurement; Pre-soaking: Place the batched salted beef hides into a drum, add 180% water at 18-20℃, 0.2% probiotic penetrant, 0.3% probiotic soaking agent, 0.1% probiotic defatting agent, and 0.5% wood ash. Rotate for 10 minutes, stop for 20 minutes; repeat twice; rotation speed 2 rpm; control temperature 19-21℃, pH 6.3-6.7, Baume degree 8-9; repeat 4 times; wash with water, remove from the drum; remove meat and trim edges; weigh, and add 150% weight for measurement; Preparation of the above-mentioned plant ash: Burn waste wood and residues from natural plant materials produced by this patented technology, collect the combustion ash, crush it, pour the plant ash into water, stir, filter out impurities, and that is the plant ash solution. Soaking: Place the pre-soaked, de-fleshed, and trimmed cowhide into a drum, add 80% water at 18-22℃, and rotate the drum at 3 rpm; add 0.2% probiotic soaking agent, 0.2% probiotic penetrant, and 0.1% probiotic defatting agent, rotate for 10 minutes, then stop for 20 minutes; control the pH to 6.3-6.7, rotate the drum at 2-3 rpm, and repeat once; add 0.5% wood ash and 0.4% plant fungicide, adjust the pH to 9.5-10.5, rotate for 10 minutes, then stop for 20 minutes; repeat 5 times until fully transparent and the cut is milky white; wash with water, remove from the drum; de-fleshed and trim the edges; weigh, and add 150% weight for measurement; Preparation of the above-mentioned plant fungicide: 1 kg of dried and pulverized plant (such as camphor leaves, tea leaves, licorice, etc.) powder is added to a subcritical treatment device, 10 kg of 30% ethanol aqueous solution is added, the device is sealed, and the reaction is carried out at a temperature of 100℃ and a pressure of 0.5 MPa for 0.5 h. After filtration, the filtrate is collected and concentrated by rotary evaporation to obtain the plant fungicide. Enzymatic hair removal: The soaked cowhide, after soaking, fleshing, and trimming, is placed into a rotating drum. 100% water at 24-28℃ is added, and the drum speed is 6 rpm. The pH is adjusted to 9.0-9.5. 0.3% probiotic penetrant, 1.0% nano negative ion powder, and 0.7-1.3% compound enzyme (refer to patent: ZL201510347968.6) are added, and the drum is rotated for 30 minutes. 0.3% keratinase is added, and the drum is rotated for 30 minutes. The hair removal is checked. If the hair removal rate is greater than 90%, proceed to the next step; otherwise, continue rotating for 30 minutes. The hide is then washed, filtered, and drained. Lime treatment: Place bovine hides with a hair removal rate >90% into a drum, add 100% water at 24-26℃, and rotate the drum at 3 rpm; add 0.3% probiotic penetrant and 2% lime, and rotate for 60 minutes; add 100% water at 24-26℃, 50% of a 15% wood ash solution, and 0.15% of a 30% sodium hydroxide solution, and rotate for 60 minutes; then rotate for 5 minutes, stop for 55 minutes, and repeat 5-8 times; wash with water, remove from the drum; remove meat, trim edges, and split layers; weigh, and add 150% weight for measurement. De-ashing: Put the de-fleshed, trimmed, and split cowhide into a drum, add 30% water at 30-35℃, 0.3% probiotic penetrant, and 1.0% citric acid (food grade, Rizhao Jinhe Biochemical Group Co., Ltd.), and rotate for 30 minutes at 6 rpm; then rotate for 90 minutes with 1.0% citric acid. Softening: Continue adding 1.0% acidic softening enzyme (TJ-A489) and 0.3% probiotic defatting agent, incubate for 10 minutes, then stop for 20 minutes; adjust the temperature to 30-32℃ and pH to 7.5-8.5, incubate for 10 minutes, then stop for 20 minutes; repeat twice. When the buttock incision shows no color change in phenolphthalein reagent, softening is considered complete; wash with water and remove from the drum; Acid soaking: Put the softened bare skin into a rotating drum, add 50% water at 20-22℃, add 7% salt, and rotate for 5 minutes; add 0.5% diluted citric acid and 0.5% sulfuric acid, adjust the pH to 2.8-3.0, and rotate for 30 minutes; Xanthan gum aldehyde-Al(III) combined tanning: Continue adding 140% water at 20-22℃ and 3% salt, and rotate for 5 minutes; add 6% xanthan gum aldehyde and rotate for 180 minutes; add 0.5% wood ash every 15 minutes to adjust the pH to 7.5-8.5, maintain the temperature at 38-42℃, and rotate for 180 minutes; wash with water, remove from the drum and let stand for 24 hours; then put it back into the drum, add 180% water at 38-42℃ and 3% citric acid, and rotate for 30 minutes; add 8% aluminum sulfate and rotate for 180 minutes; add 0.5% wood ash every 15 minutes to adjust the pH to 7.5-8.5, maintain the temperature at 38-42℃, and rotate for 180 minutes; wash with water, remove from the drum and let stand for more than 24 hours; obtain white wet leather; Preparation of the above-mentioned xanthocollagen aldehyde: 1 kg of xanthocollagen and 25 L of water were added to a light-proof reaction vessel and stirred for 8 h; 0.5 kg of sodium periodate was added, the temperature was adjusted to 8-12℃, and the reaction was carried out for 12 h; 0.1 kg of sucrose was added, and the reaction was carried out for 60 min; the pH was adjusted to 6.3-6.6; vacuum filtration was performed, and the filtrate was freeze-dried to obtain xanthocollagen aldehyde; Rehydration: Place the combined tanned white wet leather into a drum, add 300% water at 38-42℃, 0.1% probiotic penetrant, 0.1% probiotic degreasing agent, and 1% citric acid; rotate for 30 minutes; drain and dry. Neutralization: Place the rehydrated white wet leather into a drum, add 300% water at 38-42℃, 0.2% probiotic penetrant, 0.5% sodium citrate, and 0.5% wood ash, and rotate for 30 minutes; add 0.5% wood ash to adjust the pH to 5.8-6.2; drain and allow to dry. Filling: Place the neutralized wet white leather into a drum, add 100% water at 30-40℃, 1% sulfite fish oil (MIR-90, Yixiang Chemical), 4% chamomile bark tannin (ME, Shihua Technology), 4% arborvitae tannin (ATO, Shihua Technology), and 2% plant dye, and rotate for 180 minutes; add 4% waste leather collagen modifier, and rotate for 60 minutes; adjust the pH to 4.0 with citric acid, and rotate for 15 minutes; drain and dry. Preparation of plant dyes: 1 kg of dried and pulverized plant powder (such as Sophora japonica, turmeric, Polygonum tinctorium, safflower, gardenia, dragon fruit, etc.) was added to a subcritical fluid processing device, along with 10 kg of a 5% ethanol aqueous solution. The device was sealed and reacted at 100-150℃ and 0.5-1.5 MPa for 0.5 h. After filtration, the filtrate was collected and concentrated by rotary evaporation to obtain the plant dye. Preparation of modified waste leather collagen: 1 kg of chromium-free tanning waste (such as trimming scraps and shavings) and 10 L of water were added to a reaction vessel. 50 mL of copper-iron catalyst was added, and the temperature was adjusted to 70-75℃. The reaction was carried out for 5 min. 0.8 kg of hydrogen peroxide and 10 g of sulfuric acid were added, and the reaction was carried out for 60 min. The mixture was filtered, and the filtrate was freeze-dried to obtain leather collagen. 1 kg of leather collagen and 10 L of water were added to the reaction vessel. The pH was adjusted to 7.5-8.0 with sodium hydroxide, and 2% sodium alginate (dialdehyde) was added. The temperature was adjusted to 55-65℃, and the reaction was carried out for 120 min. After freeze-drying, the modified waste leather collagen was obtained. Modified rapeseed oil fatliquoring: Place the filled wet white leather into a rotating drum, add 150% water (50-60℃) and 9% modified rapeseed oil fatliquoring agent, adjust the temperature to 50-60℃, and rotate for 60 minutes; add 0.1% citric acid every 15 minutes to adjust the pH to 3.6-4.0; wash with water, drain, and dry. Preparation of modified rapeseed oil fatliquoring agent: Add 1 kg of rapeseed oil and 10 g of magnesium oxide to a reaction vessel, purge with nitrogen, adjust the temperature to 160-180℃ and the pressure to 0.3-0.4 MPa, slowly introduce 100 g of ethylene oxide, and react for 8 hours; then sulfonate using an SO3 falling film sulfonation device for 30 minutes, controlling the SO2 flow rate at 0.6-1.0 L / min, the air flow rate at 18-20 L / min, and the cooling jacket temperature at 70-75℃ to obtain ethoxylated modified sulfonated rapeseed oil; then mix 1 kg of ethoxylated modified sulfonated rapeseed oil, 0.2 kg of probiotic permeation agent, 0.1 kg of water, 40 g of surfactant, and 30 g of organosilicon defoamer evenly, adjust the pH to 7.5-8.0, and obtain the modified rapeseed oil fatliquoring agent. Dyeing: Place the fattened white wet leather into a drum, add 150% water at 55-60℃ and 1% zeolite tanning agent, and rotate for 30 minutes; then add 0.5% plant dye and rotate for 30 minutes; add 0.5% citric acid every 15 minutes to adjust the pH to 3.3-3.6 and rotate for 15 minutes; add 1% zeolite tanning agent and rotate for 15 minutes; add 0.5% GS sulfite fish oil (MIR-90, Yixiang Chemical) evenly dispersed in 5 times its volume of water at 55℃ and rotate for 15 minutes; wash with water, drain, and dry.

[0017] The above finishing process is as follows: water squeezing and stretching → vacuum drying → hanging drying → re-moistening → softening by tumbling → stretching and drying → sealing the base → troweling → top coating → softening → rolling → measuring and warehousing; the main operational points are as follows: Dewatering and stretching: Performed on a reciprocating dewatering and stretching machine with a blade spacing of 1.10 mm, a dewatering pressure of 30 bar, and a feed speed of 20 m / min; the moisture content after dewatering is controlled at 50%. Vacuum drying: carried out in a vacuum dryer at a temperature of 45℃ for 500 seconds, with a negative pressure of 23-26 Mbar; the moisture content after vacuum drying is controlled at 23%. Hanging and drying: carried out on a hanging drying line, with a hanging time of 24 hours, and the moisture content after hanging and drying is controlled at 13%; Re-humidification: carried out on a re-humidification machine, with the moisture content controlled at 20% after re-humidification; Tumbling and softening: This process is carried out in a stainless steel octagonal tumbling and softening drum at a speed of 15 r / min for 6 hours. The drum rotates in both directions, and the internal temperature is automatically controlled at 25-30℃. After tumbling and softening, the moisture content of the raw leather is 18%. Stretching: Performed on a horizontal stretching machine, oven temperature 50℃, stretching distance 6cm, clamping distance 10-12cm, raw leather time in oven 20min, raw leather moisture content 14%; Base coat: Operate on a spraying machine, with a coating amount of approximately 5g / sf, spraying 3 times, each time 3g / sf2, with a coating amount of approximately 3g / sf2; the coating agent formula is: 800 parts water, 100 parts negative ion aqueous solution (VEIKEKJP39, Hunan Kangjian Nanomaterials Technology Co., Ltd.); 500 parts water-soluble protein binder, 200 parts modified protein and modified protein gloss agent, 20 parts probiotic penetrant; 50 parts bio-based additives; Calendering: Performed on a board ironing machine at a board surface temperature of 100℃, a pressure of 30kg, and a time of 2s. Top coat: Operate on a computer-controlled sprayer, spray twice, 3g / sf2 each time, for a total coating weight of approximately 9-15g / sf2; Oscillating softening: Operated on an oscillating softening machine with the following parameters: conveying speed 9.5m / min, number of stages 5; Blazing: Operated on a pass-through ironing machine, with a temperature of 120℃, a pressure of 20kg, and a speed of 8m / min.

[0018] The above coating agent formulation is as follows: 100 parts water, 200 parts P(MMA-BA-DV) emulsion, 1.5 parts EG@MXene / Ag-MOF composite nanofiller, 20 parts penetrant, and 50 parts bio-based additives; Wherein: DV is double-bonded vanillin, which is formed by introducing a methacrylic acid double bond through Steglich esterification of vanillin; MXene is Ti3C2TX It is prepared by etching Ti3AlC2 with LiF / HCl, ultrasonic exfoliation and freeze drying; Ag-MOF is Ag-BTC, which is grown in situ on the surface of MXene; EG is eugenol, which is impregnated and encapsulated in the porous structure of MXene / Ag-MOF with an encapsulation rate of ≥15%; P(MMA-BA-DV) is methyl methacrylate-butyl acrylate-double-bonded vanillin terpolymer emulsion.

[0019] The preparation of the above formula includes the following steps: Step 1, Preparation of double-bonded vanillin (DV): Vanillin and methacrylic acid were esterified by Steglich reaction at room temperature for 6 h under DCC / DMAP catalysis; filtered, recrystallized, and vacuum dried to obtain DV; Step 2, Preparation of MXene / Ag-MOF: 1g Ti3AlC2, 0.6g LiF, 20mL 36% HCl, stirred at 35-40℃ for 48h; centrifuged, washed with water until pH≈6, ultrasonically exfoliated (30min, 300W), and freeze-dried to obtain MXene powder; 0.1g MXene was dispersed in 30mL water and ultrasonicated for 10min; 0.0849g AgNO3 and 0.1051g H3BTC were added, stirred at room temperature for 2h, and allowed to stand for 12h; centrifuged and dried to obtain MXene / Ag-MOF composite powder; Step 3, Preparation of EG@MXene / Ag-MOF: MXene / Ag-MOF and eugenol (EG) were mixed at a mass ratio of 3:1 and impregnated with ethanol for 24 hours; centrifuged and vacuum dried to obtain EG@MXene / Ag-MOF; the encapsulation efficiency was approximately 16%. Step 4, Preparation of P(MMA-BA-DV) emulsion: Aqueous phase: SDS 0.28g, n-butanol 0.40g, deionized water 30g; Oil phase: MMA, BA, DV mixed in a mass ratio of 6:3:1; The oil and water mixture was sonicated for 15min to obtain a pre-microemulsion; At 75℃, KPS 0.15g (13mL water) was added first, and after 2h, KPS 0.45g (23.5mL water) was added to the pre-microemulsion; The reaction was continued for 2h, cooled, and filtered to obtain the P(MMA-BA-DV) emulsion; Step 5, preparation of composite coating agent: 1.0 g of EG@MXene / Ag-MOF is dispersed in 10 mL of water and sonicated for 30 min; 100 g of P(MMA-BA-DV) emulsion is slowly added and stirred at room temperature for 4 h; After filtration and adjustment of the solids content to 20%, a topcoat finishing agent is obtained.

[0020] Example 2: A low-carbon preparation method for antibacterial eco-leather based on all-natural materials includes the following steps: batching → pre-soaking → fleshing and trimming → main soaking → fleshing and trimming → enzymatic hair removal → liming → splitting and trimming → deliming → softening → acid soaking → tanning with yellow collagen aldehyde-aluminum combination → standing, squeezing out water, and shaving evenly → rewetting → neutralization → filling with waste leather collagen modifiers and dyeing with plant dyes → fatliquoring with modified rapeseed oil → dyeing with plant dyes → drying and finishing → vanillin finishing; in, Batching: Using wet cowhide as raw material, weigh it and add 150% to the weight for measurement; Pre-soaking: Place the batched salted beef hides into a drum, add 200% water at 18-20℃, 0.3% probiotic penetrant, 0.5% probiotic soaking agent, 0.2% probiotic defatting agent, and 1.5% wood ash. Rotate for 10 minutes, stop for 20 minutes; repeat 3 times; rotation speed 2-3 rpm; control temperature 19-21℃, pH 6.3-6.7, Baume degree 8-9; repeat 6 times; wash with water, remove from the drum; remove meat and trim edges; weigh, and add 150% weight for measurement; Preparation of the above-mentioned plant ash: Burn waste wood and residues from natural plant materials produced by this patented technology, collect the combustion ash, crush it, pour the plant ash into water, stir, filter out impurities, and that is the plant ash solution. Soaking: Place the pre-soaked, de-fleshed, and trimmed cowhide into a drum, add 150% water at 18-22℃, and rotate the drum at 3 rpm; add 0.4% probiotic soaking agent, 0.4% probiotic penetrant, and 0.2% probiotic defatting agent, rotate for 10 minutes, then stop for 20 minutes; control the pH to 6.3-6.7, rotate at 3 rpm, and repeat 3 times; add 1.5% wood ash and 0.6% plant fungicide, adjust the pH to 9.5-10.5, rotate for 10 minutes, then stop for 20 minutes; repeat 8 times, ensuring complete penetration and a milky white cut surface; wash with water, remove from the drum; de-fleshed and trim the edges; weigh, and add 150% weight for measurement; Preparation of the above-mentioned plant fungicide: 1 kg of dried and pulverized plant (such as camphor leaves, tea leaves, licorice, etc.) powder is added to a subcritical treatment device, 15 kg of 90% ethanol aqueous solution is added, the device is sealed, and the reaction is carried out at a temperature of 100-150℃ and a pressure of 0.5-1.5MPa for 3 hours. After filtration, the filtrate is collected and concentrated by rotary evaporation to obtain the plant fungicide. Enzymatic hair removal: The soaked cowhide, after soaking, fleshing, and trimming, is placed into a rotating drum. 100% chlorine solution at 24-28℃ is added, and the drum speed is 8 rpm. The pH is adjusted to 9.0-9.5. 0.3% probiotic penetrant, 1.5% nano-negative ion powder, and 1.3% compound enzyme (patent: ZL201510347968.6) are added, and the drum is rotated for 30 minutes. 0.5% keratinase is added, and the drum is rotated for another 30 minutes. The hair removal rate is checked. If the hair removal rate is greater than 90%, proceed to the next step; otherwise, continue rotating for 60 minutes. The hide is then washed, filtered, and drained. Lime treatment: Place bovine hides with a hair removal rate >90% into a drum, add 100% water at 24-26℃, and rotate the drum at 5 rpm; add 0.3% probiotic penetrant and 2% lime, and rotate for 60 minutes; add 100% water at 24-26℃, 50% of a 25% wood ash solution, and 0.2% of a 30% sodium hydroxide solution, and rotate for 60 minutes; then rotate for 5 minutes, stop for 55 minutes, and repeat 8 times; wash with water, remove from the drum; remove meat, trim edges, and split layers; weigh, and add 150% weight for measurement. De-ashing: Put the de-fleshed, trimmed and split cowhide into a drum, add 60% water at 30-35℃, 0.3% probiotic penetrant, and 2.0% citric acid (food grade, Rizhao Jinhe Biochemical Group Co., Ltd.), and rotate for 60 minutes at 6 rpm; then add 3.0% citric acid and rotate for 180 minutes. Softening: Continue adding 3.5% acidic softening enzyme (TJ-A489) and 0.3% probiotic defatting agent, incubate for 10 minutes, then stop for 20 minutes; adjust the temperature to 30-32℃ and pH to 7.5-8.5, incubate for 10 minutes, then stop for 20 minutes; repeat 3 times. When the buttock incision shows no color change in phenolphthalein reagent, softening is considered complete; wash with water and remove from the drum; Acid soaking: Put the softened bare skin into a rotating drum, add 60% water at 20-22℃, add 7-10% salt, and rotate for 5-15 minutes; add 0.5-1.5% diluted citric acid and 1.5% sulfuric acid, adjust the pH to 2.8-3.0, and rotate for 30-90 minutes; Xanthan gum aldehyde-Al(III) combined tanning: Continue adding 160% water at 20-22℃ and 5% salt, and rotate for 15 minutes; add 10% xanthan gum aldehyde and rotate for 300 minutes; add 1.5% wood ash every 20 minutes to adjust the pH to 7.5-8.5, maintain the temperature at 38-42℃, and rotate for 300 minutes; wash with water, remove from the drum and let stand for 24 hours; then put it back into the drum, add 230% water at 38-42℃ and 3% citric acid, and rotate for 60 minutes; add 12% aluminum sulfate and rotate for 300 minutes; add 1.5% wood ash every 20 minutes to adjust the pH to 7.5-8.5, maintain the temperature at 38-42℃, and rotate for 300 minutes; wash with water, remove from the drum and let stand for more than 24 hours; obtain white wet leather; Preparation of the above-mentioned xanthocollagen aldehyde: 1 kg of xanthocollagen and 25 L of water were added to a light-proof reaction vessel and stirred for 24 h; 0.8 kg of sodium periodate was added, the temperature was adjusted to 8-12℃, and the reaction was carried out for 36 h; 0.3 kg of sucrose was added, and the reaction was carried out for 120 min; the pH was adjusted to 6.3-6.6; vacuum filtration was performed, and the filtrate was freeze-dried to obtain xanthocollagen aldehyde; Rehydration: Place the combined tanned white wet leather into the drum, add 400% water at 38-42℃, 0.3% probiotic penetrant, 0.3% probiotic degreasing agent, and 3% citric acid; rotate for 60 minutes; drain and dry. Neutralization: Place the rehydrated white wet leather into a drum, add 400% water at 38-42℃, 0.4% probiotic penetrant, 1.5% sodium citrate, and 1.5% wood ash, and rotate for 90 minutes; add 1.5% wood ash to adjust the pH to 5.8-6.2; drain and allow to dry. Filling: Place the neutralized wet white leather into a drum, add 150% water at 30-40℃, 2% sulfite fish oil (MIR-90, Yixiang Chemical), 6% chamomile bark tannin (ME, Shihua Technology), 6% arborvitae tannin (ATO, Shihua Technology), and 3% plant dye, and rotate for 180 minutes; add 6% waste leather collagen modifier, and rotate for 120 minutes; adjust the pH to 4.0 with citric acid, and rotate for 30 minutes; drain and dry. Preparation of plant dyes: 1 kg of dried and pulverized plant powder (such as Sophora japonica flower, turmeric, Polygonum tinctorium, safflower, gardenia, dragon fruit, etc.) was added to a subcritical fluid processing device, along with 15 kg of 50% ethanol aqueous solution. The device was sealed and reacted at 100-150℃ and 0.5-1.5 MPa for 3 hours. After filtration, the filtrate was collected and concentrated by rotary evaporation to obtain the plant dye. Preparation of modified waste leather collagen: 1 kg of chromium-free tanning waste (such as trimming scraps and shavings) was added to a reactor along with 15 L of water and 100 mL of copper-iron catalyst. The temperature was adjusted to 70-75℃, and the reaction was carried out for 15 min. Then, 1.2 kg of hydrogen peroxide and 30 g of sulfuric acid were added, and the reaction was carried out for 120 min. The mixture was filtered, and the filtrate was freeze-dried to obtain leather collagen. 1 kg of leather collagen and 15 L of water were added to the reactor, the pH was adjusted to 7.5-8.0 with sodium hydroxide, and 10% sodium alginate (dialdehyde) was added. The temperature was adjusted to 55-65℃, and the reaction was carried out for 180 min. After freeze-drying, the modified waste leather collagen was obtained. Modified rapeseed oil fatliquoring: Place the filled wet white leather into a rotating drum, add 150-200% water (50-60℃) and 15% modified rapeseed oil fatliquoring agent, adjust the temperature to 50-60℃, and rotate for 90 minutes; add 0.8% citric acid every 20 minutes to adjust the pH to 3.6-4.0; wash with water, drain, and dry. Preparation of modified rapeseed oil fatliquoring agent: 1 kg of rapeseed oil and 20 g of magnesium oxide were added to a reaction vessel. Nitrogen gas was introduced, and the temperature was adjusted to 160-180℃ and the pressure to 0.3-0.4 MPa. 200 g of ethylene oxide was slowly introduced, and the reaction was carried out for 12 hours. Then, sulfonation was performed for 150 minutes using an SO3 falling film sulfonation device. During sulfonation, the SO2 flow rate was controlled at 0.6-1.0 L / min, the air flow rate at 18-20 L / min, and the cooling jacket temperature at 70-75℃ to obtain ethoxylated modified sulfonated rapeseed oil. Then, 1 kg of ethoxylated modified sulfonated rapeseed oil, 0.3 kg of probiotic permeation agent, 0.2 kg of water, 50 g of surfactant, and 50 g of organosilicon defoamer were mixed evenly, and the pH was adjusted to 7.5-8.0 to obtain the modified rapeseed oil fatliquoring agent. Dyeing: Place the fattened white wet leather into a drum, add 200% water at 55-60℃ and 2% zeolite tanning agent, and rotate for 30-60 minutes; then add 2.0% plant dye and rotate for 60 minutes; add 2.0% citric acid every 20 minutes to adjust the pH to 3.3-3.6 and rotate for 20 minutes; add 2% zeolite tanning agent and rotate for 20 minutes; add 2.0% GS sulfite fish oil (MIR-90, Yixiang Chemical) evenly dispersed in 5 times its volume of water at 55℃ and rotate for 20 minutes; wash with water, drain, and dry.

[0021] The above finishing process is as follows: water squeezing and stretching → vacuum drying → hanging drying → re-moistening → softening by tumbling → stretching and drying → sealing the base → troweling → top coating → softening → rolling → measuring and warehousing; the main operational points are as follows: Dewatering and stretching: Performed on a reciprocating dewatering and stretching machine with a blade spacing of 1.15 mm, a dewatering pressure of 30 bar, and a feed speed of 25 m / min; the moisture content after dewatering is controlled at 55%. Vacuum drying: carried out in a vacuum dryer at a temperature of 45℃ for 500 seconds, with a negative pressure of 23-26 Mbar; the moisture content after vacuum drying is controlled at 30%. Hanging and drying: carried out on a hanging drying line, with a hanging time of 24 hours, and the moisture content after hanging and drying is controlled at 18%; Re-humidification: carried out on a re-humidification machine, with the moisture content controlled at 25% after re-humidification; Tumbling and softening: This is carried out in a stainless steel octagonal tumbling and softening drum at a speed of 15 r / min for 6 hours. The drum rotates in both directions, and the internal temperature is automatically controlled at 25-30℃. After tumbling and softening, the moisture content of the raw leather is 20%. Stretching: Performed on a horizontal stretching machine, oven temperature 50℃, stretching distance 6cm, clamping distance 10-12cm, raw leather time in oven 20min, raw leather moisture content 18%; Base coat: Apply using a spray gun, with a coating amount of approximately 5-10 g / sf, spraying 3 times, each time 5 g / sf2, for a total coating amount of approximately 15 g / sf2; the coating agent formula is as follows: 800 parts water, 200 parts negative ion aqueous solution (VEIKEKJP39, Hunan Kangjian Nanomaterials Technology Co., Ltd.); 800 parts water-soluble protein binder, 300 parts modified protein and modified protein gloss agent, 100 parts probiotic penetrant; 100 parts bio-based additives; Calendering: Performed on a board ironing machine at a board surface temperature of 100℃, a pressure of 30kg, and a time of 2s. Top coat: Operate on a computer-controlled sprayer, spray 2-3 times, each time 3-5g / sf2, with a coating amount of about 9-15g / sf2; Oscillating softening: Operated on an oscillating softening machine with the following parameters: conveying speed 9.5m / min, number of stages 5; Blazing: Operated on a pass-through ironing machine, with a temperature of 120℃, a pressure of 20-30kg, and a speed of 8m / min.

[0022] The above coating agent formulation is as follows: 300 parts water, 300 parts P(MMA-BA-DV) emulsion, 2.5 parts EG@MXene / Ag-MOF composite nanofiller, 100 parts penetrant, and 100 parts bio-based additives; Wherein: DV is double-bonded vanillin, which is formed by introducing a methacrylic acid double bond through Steglich esterification of vanillin; MXene is Ti3C2T X It is prepared by etching Ti3AlC2 with LiF / HCl, ultrasonic exfoliation and freeze drying; Ag-MOF is Ag-BTC, which is grown in situ on the surface of MXene; EG is eugenol, which is impregnated and encapsulated in the porous structure of MXene / Ag-MOF with an encapsulation rate of ≥15%; P(MMA-BA-DV) is methyl methacrylate-butyl acrylate-double-bonded vanillin terpolymer emulsion.

[0023] The preparation of the above formula includes the following steps: Step 1, Preparation of double-bonded vanillin (DV): Vanillin and methacrylic acid were esterified by Steglich reaction at room temperature for 12 h under DCC / DMAP catalysis; filtered, recrystallized and vacuum dried to obtain DV; Step 2, Preparation of MXene / Ag-MOF: 1 g Ti3AlC2, 1.0 g LiF, 20 mL 36% HCl, stirred at 35-40℃ for 48 h; centrifuged, washed with water until pH≈6, ultrasonically exfoliated (30 min, 300 W), and freeze-dried to obtain MXene powder; 0.1 g MXene was dispersed in 30 mL water and ultrasonicated for 10 min; 0.0849 g AgNO3 and 0.1051 g H3BTC were added, stirred at room temperature for 2 h, and allowed to stand for 12 h; centrifuged and dried to obtain MXene / Ag-MOF composite powder; Step 3, Preparation of EG@MXene / Ag-MOF: MXene / Ag-MOF and eugenol (EG) were mixed at a mass ratio of 3:1 and impregnated with ethanol for 24 hours; centrifuged and vacuum dried to obtain EG@MXene / Ag-MOF; the encapsulation efficiency was approximately 16%. Step 4, Preparation of P(MMA-BA-DV) emulsion: Aqueous phase: SDS 0.28g, n-butanol 0.40g, deionized water 30g; Oil phase: MMA, BA, DV mixed in a mass ratio of 6:3:1; The oil and water mixture was sonicated for 15min to obtain a pre-microemulsion; At 75℃, KPS 0.15g (13mL water) was added first, and after 2h, KPS 0.45g (23.5mL water) was added to the pre-microemulsion; The reaction was continued for 2h, cooled, and filtered to obtain the P(MMA-BA-DV) emulsion; Step 5, preparation of composite coating agent: 1.0 g of EG@MXene / Ag-MOF is dispersed in 10 mL of water and sonicated for 30 min; 100 g of P(MMA-BA-DV) emulsion is slowly added and stirred at room temperature for 4 h; After filtration and adjustment of the solids content to 20%–30%, a topcoat finishing agent is obtained.

[0024] Product Performance: Leather products contain >90% biochar, which is effective against Staphylococcus aureus and Klebsiella pneumoniae. The antibacterial rate against bacteria and Candida albicans is >99%; it meets the industry standard for chrome-free tanned leather for shoe uppers and the Class A standard requirements of the Green Design Product Evaluation Technical Specification for Leather, as detailed below: The antibacterial performance was tested according to Appendix B of QB / T 2881-2013 "Technical Conditions for Antibacterial Performance of Footwear and Footwear Components" using the bacterial solution absorption method. The sterilization method was high-pressure steam sterilization at 115°C for 30 min; the sample size was 4.8 cm ± 1.0 cm; one sample was used, absorbing 1 mL of bacterial solution; the test conditions were before washing. The test results are as follows:

[0025] The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. A low-carbon preparation method for antibacterial eco-leather based on all-natural materials, characterized in that, The process includes the following steps: batching → pre-soaking → fleshing and trimming → main soaking → fleshing and trimming → enzymatic hair removal → liming → splitting and trimming → deliming → softening → acid soaking → aldehyde-aluminum tanning with yellow collagen → settling, squeezing out water, and shaving → rewetting → neutralization → filling with modified waste leather collagen and dyeing with plant dyes → fatliquoring with modified rapeseed oil → dyeing with plant dyes → drying and finishing → vanillin finishing; in, Batching: Using wet cowhide as raw material, weigh it and add 150% to the weight for measurement; Pre-soaking: Place the batched salted beef hides into a drum, add 180-200% water at 18-20℃, 0.2-0.3% probiotic penetrant, 0.3-0.5% probiotic soaking agent, 0.1-0.2% probiotic defatting agent, and 0.5-1.5% wood ash. Rotate for 10 minutes, stop for 20 minutes; repeat 2-3 times; rotation speed 2-3 rpm; control temperature 19-21℃, pH 6.3-6.7, Baume degree 8-9; repeat 4-6 times; wash with water, remove from the drum; remove meat and trim edges; weigh, and add 150% weight for measurement; Preparation of plant ash: Burn waste wood and residues from natural plant materials produced by this patented technology, collect the ash, crush it, pour the plant ash into water, stir, filter out impurities, and that is the plant ash solution. Soaking: Place the pre-soaked, de-fleshed, and trimmed cowhide into a drum, add 80-150% water at 18-22℃, and rotate the drum at 3 rpm; add 0.2-0.4% probiotic soaking agent, 0.2-0.4% probiotic penetrant, and 0.1-0.2% probiotic defatting agent, rotate for 10 minutes, then stop for 20 minutes; control the pH at 6.3-6.7, rotate the drum at 2-3 rpm, and repeat 1-3 times; add 0.5-1.5% wood ash and 0.4-0.6% plant fungicide, adjust the pH to 9.5-10.5, rotate for 10 minutes, then stop for 20 minutes; repeat 5-8 times until fully saturated and the cut is milky white; wash with water, remove from the drum; de-fleshed and trim; weigh, and add 150% weight for measurement; Preparation of the plant fungicide: 1 kg of dried and pulverized plant powder is added to a subcritical treatment device, 10-15 kg of 30-90% ethanol aqueous solution is added, the device is sealed, and the reaction is carried out at a temperature of 100-150℃ and a pressure of 0.5-1.5 MPa for 0.5-3 hours. The mixture is filtered, the filtrate is collected, and the plant fungicide is obtained by rotary evaporation and concentration. Enzymatic hair removal: After soaking, removing flesh, and trimming, the soaked cowhide is placed into a rotating drum. 100% chlorine solution at 24-28℃ is added, and the drum speed is 6-8 rpm. The pH is adjusted to 9.0-9.

5. 0.3% probiotic penetrant, 1.0-1.5% nano-negative ion powder, and 0.7-1.3% compound enzyme are added, and the drum is rotated for 30 minutes. 0.3-0.5% keratinase is added, and the drum is rotated for another 30 minutes. The hair removal rate is checked. If the hair removal rate is greater than 90%, proceed to the next step; otherwise, continue rotating for 30-60 minutes. The hide is then washed, the hair is filtered, and the liquid is drained. Lime treatment: Place the de-limed bovine hides (with a hair removal rate >90%) into a drum, add 100% water at 24-26℃, and rotate the drum at 3-5 rpm; add 0.3% probiotic penetrant and 2% lime, and rotate for 60 minutes; add 100% water at 24-26℃, 50% of a 15-25% wood ash solution, and 0.15-0.2% of a 30% sodium hydroxide solution, and rotate for 60 minutes; then rotate for 5 minutes, stop for 55 minutes, and repeat 5-8 times; wash with water, remove from the drum; remove meat, trim edges, and split layers; weigh, and add 150% weight for measurement. De-ashing: Put the de-fleshed, trimmed, and split cowhide into a drum, add 30-60% water at 30-35℃, 0.3% probiotic penetrant, and 1.0-2.0% citric acid, and rotate for 30-60 minutes at 6 rpm; or add 1.0-3.0% citric acid and rotate for 90-180 minutes. Softening: Continue adding 1.0-3.5% acidic softening enzyme and 0.3% probiotic defatting agent, incubate for 10 minutes, then stop for 20 minutes; adjust the temperature to 30-32℃ and pH to 7.5-8.5, incubate for 10 minutes, then stop for 20 minutes; repeat 2-3 times. When the buttock incision shows no color change in phenolphthalein reagent, softening is considered complete; wash with water and remove from the drum; Acid soaking: Put the softened bare skin into a rotating drum, add 50-60% water at 20-22℃, add 7-10% salt, and rotate for 5-15 minutes; add 0.5-1.5% diluted citric acid and 0.5-1.5% sulfuric acid, adjust the pH to 2.8-3.0, and rotate for 30-90 minutes; Xanthan gum aldehyde-Al(III) combined tanning: Continue adding 140-160% water at 20-22℃ and 3-5% salt, and rotate for 5-15 minutes; add 6-10% xanthan gum aldehyde and rotate for 180-300 minutes; add 0.5-1.5% wood ash every 15-20 minutes to adjust the pH to 7.5-8.5, maintain the temperature at 38-42℃, and rotate for 180-300 minutes; wash with water, remove from the drum and let stand for 24 hours; then put it back into the drum, add 180-230% water at 38-42℃ and 2-3% citric acid, and rotate for 30-60 minutes; add 8-12% aluminum sulfate and rotate for 180-300 minutes; add 0.5-1.5% wood ash every 15-20 minutes to adjust the pH to 7.5-8.5, maintain the temperature at 38-42℃, and rotate for 180-300 minutes; wash with water, remove from the drum and let stand for more than 24 hours; obtain white wet leather; Preparation of the yellow collagen aldehyde: 1 kg of yellow collagen and 25 L of water were added to a light-shielded reaction vessel and stirred for 8-24 h; 0.5-0.8 kg of sodium periodate was added, the temperature was adjusted to 8-12℃, and the reaction was carried out for 12-36 h; 0.1-0.3 kg of sucrose was added, and the reaction was carried out for 60-120 min; the pH was adjusted to 6.3-6.6; the mixture was vacuum filtered, and the filtrate was freeze-dried to obtain yellow collagen aldehyde. Rehydration: Place the combined-tanned white wet leather into a drum, add 300-400% water at 38-42℃, 0.1-0.3% probiotic penetrant, 0.1-0.3% probiotic degreasing agent, and 1-3% citric acid; rotate for 30-60 minutes; drain and dry. Neutralization: Place the rehydrated white wet leather into a drum, add 300-400% water at 38-42℃, 0.2-0.4% probiotic penetrant, 0.5-1.5% sodium citrate, and 0.5-1.5% wood ash, and rotate for 30-90 minutes; add 0.5-1.5% wood ash to adjust the pH to 5.8-6.2; drain and allow to dry. Filling: Place the neutralized wet white leather into a drum, add 100-150% water at 30-40℃, 1-2% sulfite fish oil, 4-6% tannin from vitex bark, 4-6% tannin from oak trees, and 2-3% plant dye, and rotate for 120-180 minutes; add 4-6% modified waste leather collagen, and rotate for 60-120 minutes; adjust the pH to 4.0 with citric acid, and rotate for 15-30 minutes; drain and dry. Preparation of plant dyes: 1 kg of dried and pulverized plant powder is added to a subcritical fluid processing device, along with 10-15 kg of a 5-50% ethanol aqueous solution. The device is sealed and reacted at 100-150℃ and 0.5-1.5 MPa for 0.5-3 hours. After filtration, the filtrate is collected and concentrated by rotary evaporation to obtain the plant dye. Preparation of modified waste leather collagen: Add 1 kg of chromium-free tanning waste, 10-15 L of water, and 50-100 mL of copper-iron catalyst to a reaction vessel. Adjust the temperature to 70-75℃ and react for 5-15 min. Add 0.8-1.2 kg of hydrogen peroxide and 10-30 g of sulfuric acid, and react for 60-120 min. Filter the mixture, and freeze-dry the filtrate to obtain leather collagen. Continue adding 1 kg of leather collagen and 10-15 L of water to the reaction vessel. Adjust the pH to 7.5-8.0 with sodium hydroxide, add 2-10% sodium alginate, and adjust the temperature to 55-65℃. React for 120-180 min. Freeze-dry the mixture to obtain the modified waste leather collagen. Modified rapeseed oil fatliquoring: Place the filled wet white leather into a rotating drum, add 150-200% water (50-60℃), 9-15% modified rapeseed oil fatliquoring agent, adjust the temperature to 50-60℃, and rotate for 60-90 minutes; add 0.1-0.8% citric acid every 15-20 minutes to adjust the pH to 3.6-4.0; wash with water, drain, and dry. Preparation of modified rapeseed oil fatliquoring agent: Add 1 kg of rapeseed oil and 10-20 g of magnesium oxide to a reaction vessel, purge with nitrogen, adjust the temperature to 160-180℃ and the pressure to 0.3-0.4 MPa, slowly introduce 100-200 g of ethylene oxide, and react for 8-12 hours; then sulfonate using an SO3 falling film sulfonation device for 30-150 minutes, controlling the SO2 flow rate at 0.6-1.0 L / min, the air flow rate at 18-20 L / min, and the cooling jacket temperature at 70-75℃ during sulfonation to obtain ethoxylated modified sulfonated rapeseed oil; then mix 1 kg of ethoxylated modified sulfonated rapeseed oil, 0.2-0.3 kg of probiotic permeation solution, 0.1-0.2 kg of water, 40-50 g of surfactant, and 30-50 g of organosilicon defoamer evenly, adjust the pH to 7.5-8.0, and obtain the modified rapeseed oil fatliquoring agent. Dyeing: Place the fattened white wet leather into a drum, add 150-200% water at 55-60℃ and 1-2% zeolite tanning agent, and rotate for 30-60 minutes; then add 0.5-2.0% plant dye and rotate for 30-60 minutes; add 0.5-2.0% citric acid at 15-20 minutes intervals to adjust the pH to 3.3-3.6, and rotate for 15-20 minutes; add 1-2% zeolite tanning agent and rotate for 15-20 minutes; add 0.5-2.0% GS sulfite fish oil evenly dispersed in 5 times its volume of water at 55℃, and rotate for 15-20 minutes; wash with water, drain, and dry.

2. The method for preparing antibacterial eco-leather based on all-natural materials in a low-carbon manner according to claim 1, characterized in that, The finishing process is as follows: water squeezing and stretching → vacuum drying → hanging drying → rehydration → softening by tumbling → stretching and drying → sealing the base → calendering → top coating → softening → rolling → measuring and warehousing; the main operational points are as follows. Dewatering and stretching: Performed on a reciprocating dewatering and stretching machine with a blade spacing of 1.10-1.15 mm, a dewatering pressure of 30 bar, and a feed speed of 20-25 m / min; the moisture content after dewatering is controlled at 50-55%. Vacuum drying: carried out in a vacuum dryer at a temperature of 45℃ for 500 seconds, with a negative pressure of 23-26 Mbar; the moisture content after vacuum drying is controlled at 23-30%. Hanging and drying: carried out on a hanging drying line, with a hanging time of 24 hours. After hanging and drying, the moisture content is controlled at 13-18%. Rehydration: Performed on a rehydration machine, the moisture content is controlled at 20-25% after rehydration; Tumbling and softening: This is carried out in a stainless steel octagonal tumbling and softening drum at a speed of 15 r / min for 6 hours. The drum rotates in both directions, and the internal temperature is automatically controlled at 25-30℃. After tumbling and softening, the moisture content of the raw leather is 18-20%. Stretching: Performed on a horizontal stretching machine, oven temperature 50℃, stretching distance 6cm, clamping distance 10-12cm, raw leather time in oven 20min, raw leather moisture content 14%-18%; Base coat: Operate on a spraying machine, with a coating amount of approximately 5-10 g / sf, spraying 1-3 times, each time 3-5 g / sf2, with a coating amount of approximately 3-15 g / sf2; the coating agent formula is as follows: 400-800 parts water, 100-200 parts negative ion aqueous solution; 500-800 parts water-soluble protein binder, 200-300 parts modified protein and modified protein gloss agent, 20-100 parts probiotic penetrant; 50-100 parts bio-based additives; Calendering: Performed on a board ironing machine at a board surface temperature of 100℃, a pressure of 30kg, and a time of 2s. Top coat: Operate on a computerized spraying machine, spray the coating agent 2-3 times, 3-5g / sf2 each time, with a coating amount of about 9-15g / sf2; Oscillating softening: Operated on an oscillating softening machine with the following parameters: conveying speed 9.5m / min, number of stages 5; Blazing: Operated on a pass-through ironing machine, with a temperature of 120℃, a pressure of 20-30kg, and a speed of 8m / min.

3. The method for preparing antibacterial eco-leather based on all-natural materials in a low-carbon manner according to claim 2, characterized in that, The coating agent formulation is as follows: 100-300 parts water, 200-300 parts P(MMA-BA-DV) emulsion, 1.5-2.5 parts EG@MXene / Ag-MOF composite nanofiller, 20-100 parts penetrant, and 50-100 parts bio-based additives; Wherein: DV is double-bonded vanillin, which is formed by introducing a methacrylic acid double bond through Steglich esterification of vanillin; MXene is Ti3C2T X It is prepared by etching Ti3AlC2 with LiF / HCl, ultrasonic exfoliation and freeze drying; Ag-MOF is Ag-BTC, which is grown in situ on the surface of MXene; EG is eugenol, which is impregnated and encapsulated in the porous structure of MXene / Ag-MOF with an encapsulation rate of ≥15%; P(MMA-BA-DV) is methyl methacrylate-butyl acrylate-double-bonded vanillin terpolymer emulsion.

4. The method for preparing antibacterial eco-leather based on all-natural materials in a low-carbon manner according to claim 3, characterized in that, The preparation of the formula includes the following steps: Step 1, Preparation of double-bonded vanillin (DV): Vanillin and methacrylic acid were esterified by Steglich reaction at room temperature for 6-12 h under DCC / DMAP catalysis; filtered, recrystallized, and vacuum dried to obtain DV; Step 2, Preparation of MXene / Ag-MOF: 1 g Ti3AlC2, 0.6-1.0 g LiF, 20 mL 36% HCl, stirred at 35-40℃ for 48 h; centrifuged, washed with water until pH≈6, ultrasonically exfoliated (30 min, 300 W), and freeze-dried to obtain MXene powder; 0.1 g MXene was dispersed in 30 mL water and ultrasonicated for 10 min; 0.0849 g AgNO3 and 0.1051 g H3BTC were added, stirred at room temperature for 2 h, and allowed to stand for 12 h; centrifuged and dried to obtain MXene / Ag-MOF composite powder; Step 3, Preparation of EG@MXene / Ag-MOF: MXene / Ag-MOF and eugenol (EG) were mixed at a mass ratio of 3:1 and impregnated with ethanol for 24 hours; centrifuged and vacuum dried to obtain EG@MXene / Ag-MOF; the encapsulation efficiency was approximately 16%. Step 4, Preparation of P(MMA-BA-DV) emulsion: Aqueous phase: SDS 0.28g, n-butanol 0.40g, deionized water 30g; Oil phase: MMA, BA, DV mixed in a mass ratio of 6:3:1; The oil and water mixture was sonicated for 15min to obtain a pre-microemulsion; At 75℃, KPS 0.15g (13mL water) was added first, and after 2h, KPS 0.45g (23.5mL water) was added to the pre-microemulsion; The reaction was continued for 2h, cooled, and filtered to obtain the P(MMA-BA-DV) emulsion; Step 5, preparation of composite coating agent: 1.0 g of EG@MXene / Ag-MOF is dispersed in 10 mL of water and sonicated for 30 min; 100 g of P(MMA-BA-DV) emulsion is slowly added and stirred at room temperature for 4 h; After filtration and adjustment of the solids content to 20%–30%, a topcoat finishing agent is obtained.

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