Preparation method of antibacterial retanning agent and wet dyeing and finishing process of antibacterial leather

Abstract

The invention relates to a preparation method of an antibacterial retanning agent, which comprises the following steps: dissolving a rare earth oxide in hydrochloric acid with the ratio of 1: 1, and evaporating until the rare earth oxide is nearly dry to prepare a rare earth chloride; the preparation method comprises the following steps: adding 10mol of phenanthroline into an absolute ethyl alcohol solution containing 10mmol of LaCl3. 6H2O, stirring, dropwise adding an absolute ethyl alcohol solution containing 30mmol of methacrylic acid, carrying out centrifugal separation, and drying in a P4O10 vacuum dryer until the weight is constant, so as to obtain the antibacterial retanning agent rare earth organic complex. The invention relates to a wet dyeing and finishing process of antibacterial leather. The wet dyeing and finishing process comprises the steps of wet blue leather preparation, wringing and shaving, softening, retanning, neutralizing, filling, dyeing, fat liquoring, water washing and bulging, stretching, vacuum drying and antibacterial leather crust leather preparation. Wherein in retanning, 100% of water and 2% of a chrome tanning agent are added, and rotation is conducted for 2 hours; and adding an antibacterial retanning agent rare earth organic complex. The crust leather is endowed with excellent antibacterial performance, a complex formed by rare earth ions and o-phenanthroline has higher antibacterial activity, is superior to a single ligand or rare earth ions, and is low in toxicity and free of drug resistance.

Description

Technical Field

[0001] The invention relates to the technical field of leather manufacturing, in particular to a method for preparing an antibacterial retanning agent and a wet dyeing and finishing process for antibacterial leather. Background Art

[0002] With the development of science and technology and the improvement of human living standards, people are paying more and more attention to the health of the body and the convenience of life. Therefore, the health of living and working environment and supplies has become the current development trend, and antibacterial products have gradually developed rapidly as civilian products. Harmful bacteria, fungi, viruses and other microorganisms in nature are the main causes of human infection and disease induction. People frequently come into contact with a large number of bacteria in their daily work and life. Most of these bacteria are pathogenic bacteria, which directly threaten people's health. In order to kill these bacteria, in addition to regular scrubbing and cleaning, they are often sterilized with agents such as hydrogen peroxide, chlorine and bleaching powder or disinfected with high-pressure steam, ultraviolet rays, etc. However, no matter which agent or method is used, the sterilization effect cannot be maintained for a long time, and special drug application equipment or special disinfection equipment must be used, and the cost of sterilization and disinfection is high. In order to improve human health, improve living and working environment, and improve the quality of life, research and development of new, efficient, non-toxic and side-effect, excellent durability, practical and economical antibacterial agents and antibacterial materials is one of the important topics of current researchers.

[0003] In particular, leather is a collagen-based polymer material, which is easily attacked by harmful microorganisms such as bacteria and viruses. Leather products cannot be washed frequently, and simply wiping and drying them in the sun cannot completely remove sweat or dirt residues. Under suitable temperature and humidity conditions, it is easy to breed a large number of harmful microorganisms such as bacteria and viruses, causing mold and rot, which seriously affects the quality of leather products and also poses a serious threat to human health.

[0004] There is almost no special antibacterial process in the conventional leather making process. The purpose of inhibiting the mildew of leather is mainly achieved by adding mildew inhibitors during the leather making process. However, mildew inhibitors have problems such as high toxicity, high cost, poor permeability, environmental pollution, and bacteria are prone to drug resistance. In addition, adding antibacterial agents in the later production process of leather products can also make leather products have certain antibacterial and self-cleaning capabilities, but their antibacterial durability is poor. Therefore, in order to give leather and leather products long-lasting and efficient antibacterial properties, it is necessary to combine the research and development innovation of antibacterial materials with the optimization and upgrading of leather making processes. Summary of the invention

[0005] The invention provides a method for preparing an antibacterial retanning agent and a wet dyeing and finishing process for antibacterial leather, so as to overcome the problem of poor antibacterial durability of existing leather.

[0006] The present invention adopts the following technical solution:

[0007] A method for preparing an antibacterial retanning agent comprises the following steps:

[0008] 1) dissolving the rare earth oxide La2O3 in hydrochloric acid with a concentration of 1:1, i.e., a 50% hydrochloric acid aqueous solution, and evaporating to near dryness to obtain the rare earth chloride LaCl3·6H2O;

[0009] 2) Add 10 mmol of o-phenanthroline (Phen) to 40-60 mL of anhydrous ethanol solution containing 10 mmol of LaCl3·6H2O, stir until a milky white precipitate is generated, and react for 1-2 hours;

[0010] 3) Then add 40-60 mL of anhydrous ethanol solution of 30 mmol methacrylic acid (C3H5COOH) dropwise, the mixture becomes clear, and the reaction is continued, and a precipitate is generated;

[0011] 4) After 5-6 hours of reaction, centrifuge and wash the precipitate several times with anhydrous ethanol and place it in P4O 10 The mixture was dried in a vacuum dryer to a constant weight to obtain the antibacterial retanning agent rare earth organic complex La(C3H5CO2)3(Phen).

[0012] A wet dyeing and finishing process for antibacterial leather, comprising the following steps: wet blue leather → squeezing, shaving → softening → retanning → neutralization → filling → dyeing → fatliquoring → washing, drum discharge → stretching, vacuum, drying → antibacterial leather crust;

[0013] For retanning, add 100% water and 2% chrome tanning agent and rotate for 2 hours; add 1% to 3% of the above-mentioned antibacterial retanning agent rare earth organic complex and rotate for 1 hour.

[0014] The wet blue leather is squeezed and shaved: the wet blue leather is squeezed to control the moisture content to about 40%, and the shaved thickness is 1.2 mm.

[0015] Weighing: The weight of wet blue leather after shaving is used as the basis for subsequent chemical material dosage;

[0016] The above-mentioned softening: the wet blue leather is put into a drum, 200% water, 0.3% oxalic acid, and 0.3% rewetting agent OC (Starr Fine Coatings Co., Ltd.) are added, and the drum is rotated for 2 hours. The whole wet blue leather is thoroughly water-recovered, the leather body is soft, and the water is drained.

[0017] The above neutralization: add 1.2% sodium formate, rotate for 20 minutes; add 1.6% baking soda, rotate for 1 hour, and measure the pH value at 5.0-5.2.

[0018] The above filling: add 3% of melamine resin DLF (Stahl Fine Coatings Co., Ltd.), 3% of dicyandiamide resin R19 (Tiger Chemical Co., Ltd.), and 2% of acrylic resin R83 (Temper Chemical Co., Ltd.), rotate for 90 minutes, and drain.

[0019] For the above dyeing: add 50% water, 1.2% dye, and rotate for 60 minutes; add 1% formic acid and rotate for 20 minutes.

[0020] The above fatliquoring: water supplementation 100%, temperature 50°C, addition of synthetic oil 94S (Sima Chemical Co., Ltd.) 8%, sulfited fish oil MIR 90 (Yixiang Chemical Co., Ltd.) 4%, rotation for 60 minutes; addition of formic acid 1.5%, rotation for 30 minutes.

[0021] The rare earth ions and o-phenanthroline of the present application have certain antibacterial properties, and the antibacterial activity of the complex formed is better than that of a single ligand and a rare earth ion, mainly because the rare earth ions and the ligands have a synergistic effect, which is less toxic than many traditional antibacterial organic synthetics or transition metal complexes and does not produce drug resistance.

[0022] The rare earth elements of the present application have unique electronic structures and chemical properties, and react chemically with leather collagen fibers to form stable chemical bonds. The formation of these chemical bonds strengthens the bonding force between leather fibers, making the leather more durable. The distribution of rare earth elements in leather also plays a certain physical filling role, making the leather structure more compact, thereby improving the density and strength of the leather. When rare earth elements are used in combination with other tanning agents (such as chrome tanning agents, vegetable tanning agents, etc.), a synergistic effect will occur between them, which can reduce the amount of chromium by more than 30%, while reducing the content of chromium ions in waste tanning liquid and improving the utilization rate of chromium.

[0023] The rare earth elements of the present application react with active groups (such as ~NH2, ~COOH) on leather fibers to form stable chemical bonds, enhance fiber activity, and promote its combination with dye molecules. Rare earth elements complex with sulfonic acid groups, carboxyl groups and other groups in dye molecules to form high-solubility rare earth dye complexes, which help to evenly distribute the dye in the dyeing medium. Rare earth elements adjust the surface charge of leather fibers, promote dye adsorption, diffusion and penetration, and improve dyeing rate, which can reduce the amount of dye used by more than 20%. Rare earth elements act as a bridge between dyes and fibers, enhance bonding strength, and improve color fastness and durability.

[0024] The methacrylic acid of the present application reacts chemically with the active groups (such as ~NHs) on the leather collagen fibers through the active groups such as carboxyl groups in its molecules to form multi-point bonds. This combination enhances the network of fibers in the loose parts of the leather edges and belly, effectively filling the loose parts in the leather, making the texture of the leather tighter and more uniform, and improving the physical and chemical properties of the leather. The combination of methacrylic acid and leather collagen fibers helps to form new intermolecular bonds in the collagen structure. These bonds enhance the stability of the leather, thereby increasing the shrinkage temperature of the leather. The stability of leather tanned with methacrylic acid in a hot and humid environment is significantly improved, and it can resist the adverse effects of a hot and humid environment on the performance of the leather; its ability to resist chemicals such as acids, alkalis, and enzymes is also enhanced, making the leather more durable in a wider range of usage environments.

[0025] It can be seen from the above description of the present invention that, compared with the prior art, the present invention has the following advantages:

[0026] 1. When the rare earth elements of the present application are used in combination with other tanning agents, the amount of chromium used can be significantly reduced (more than 30%), the content of chromium ions in waste tanning liquid can be reduced, the utilization rate of chromium can be increased, and it is beneficial to environmental protection;

[0027] 2. The rare earth elements of the present application form stable chemical bonds with leather collagen fibers, which enhance the bonding force between leather fibers, making the leather more durable, while also increasing the density and strength of the leather;

[0028] 3. The rare earth elements of the present application promote the combination of dyes and leather fibers, improve the dyeing rate, reduce the amount of dyes used (more than 20%), and at the same time enhance the color fastness and durability, thereby improving the dyeing quality of leather;

[0029] 4. The methacrylic acid of the present application enhances the network of fibers in the loose parts of the leather side and belly through multi-point bonding, has a selective filling effect, makes the leather texture more compact and uniform, improves the physical and chemical properties of the leather and its stability in a humid, hot and chemical environment, and enhances the durability of the leather;

[0030] 5. The present invention imparts excellent antibacterial properties to the leather. The complex formed by rare earth ions and o-phenanthroline has stronger antibacterial activity, which is better than a single ligand or rare earth ion, and has low toxicity and does not produce drug resistance. DETAILED DESCRIPTION

[0031] Embodiment 1:

[0032] Rare earth oxide (La2O3, purity> 9 9.9%) was dissolved in hydrochloric acid with a concentration of 1:1, and evaporated to near dryness to obtain rare earth chloride (LaCl3·6H2O); 10 mmol o-phenanthroline (Phen) was added to 40 mL of anhydrous ethanol solution containing 10 mmol LaCl3·6H2O, and stirred, and a milky white precipitate was generated. After reacting for 1-2 hours, 60 mL of anhydrous ethanol solution of 30 mmol methyl acrylic acid (C3H5 COOH) was added dropwise thereto, and the mixture became clear. The reaction was continued, and a precipitate was generated. After about 5-6 hours, the precipitate was separated by centrifugation, and washed several times with anhydrous ethanol and placed in P4O 10 The mixture was dried in a vacuum dryer to a constant weight to obtain the antibacterial retanning agent rare earth organic complex La(C3 H5 CO2)3(Phen).

[0033] (2) Squeeze and shave wet blue leather: squeeze wet blue leather to control the moisture content to about 40% and shave to a thickness of 1.2 mm;

[0034] Weighing: The weight of wet blue leather after shaving is used as the basis for subsequent chemical material dosage;

[0035] Softening: Put the wet blue leather into a drum, add 200% water, 0.3% oxalic acid, and 0.3% rewetting agent OC (Starr Fine Coatings Co., Ltd.), rotate for 2 hours, and the whole wet blue leather will be thoroughly hydrated, the leather body will be soft, and the water will be drained;

[0036] Retanning: add 100% water, 2% chrome tanning agent, and rotate for 2 hours; add 2% rare earth antibacterial retanning agent, and rotate for 1 hour;

[0037] Neutralization: add 1.2% sodium formate, rotate for 20 minutes; add 1.6% baking soda, rotate for 1 hour, and measure the pH value at 5.0-5.2;

[0038] Filling: add 3% of melamine resin DLF (Stahl Fine Coatings Co., Ltd.), 3% of dicyandiamide resin R19 (Taige Chemical Co., Ltd.), 2% of acrylic resin R 83 (Temper Chemical Co., Ltd.), rotate for 90 minutes, and drain;

[0039] Dyeing: add 50% water, 1.2% dye, rotate for 60 minutes; add 1% formic acid, rotate for 20 minutes;

[0040] Fat-liquoring: add 100% water, temperature 50°C, add 8% synthetic oil 94S (Sima Chemical Co., Ltd.), 4% sulfited fish oil MIR 90 (Yixiang Chemical Co., Ltd.), rotate for 60 minutes; add 1.5% formic acid, rotate for 30 minutes;

[0041] The antibacterial leather crust is obtained by washing, drumming, stretching, vacuuming and drying.

[0042] Embodiment 2:

[0043] Rare earth oxide (La2O3, purity> 9 9.9%) was dissolved in hydrochloric acid with a concentration of 1:1, and evaporated to near dryness to obtain rare earth chloride (LaCl3·6H2O); 10 mmol o-phenanthroline (Phen) was added to 60 mL of anhydrous ethanol solution containing 10 mmol LaCl3·6H2O, and stirred, and a milky white precipitate was generated. After reacting for 1-2 hours, 40 mL of anhydrous ethanol solution of 30 mmol methyl acrylic acid (C3H5 COOH) was added dropwise thereto, and the mixture became clear. The reaction was continued, and a precipitate was generated. After about 5-6 hours, the precipitate was separated by centrifugation, and the precipitate was washed several times with anhydrous ethanol and placed in P4O 10 The mixture was dried in a vacuum dryer to a constant weight to obtain the antibacterial retanning agent rare earth organic complex La(C3 H5 CO2)3(Phen).

[0044] Squeeze and shave wet blue leather: squeeze wet blue leather, control the moisture content to about 40%, and shave to a thickness of 1.2mm;

[0045] Weighing: The weight of wet blue leather after shaving is used as the basis for subsequent chemical material dosage;

[0046] Softening: Put the wet blue leather into a drum, add 200% water, 0.3% oxalic acid, and 0.3% rewetting agent OC (Starr Fine Coatings Co., Ltd.), rotate for 2 hours, and the whole wet blue leather will be thoroughly hydrated, the leather body will be soft, and the water will be drained;

[0047] Retanning: add 100% water, 2% chrome tanning agent, and rotate for 2 hours; add 3% rare earth antibacterial retanning agent, and rotate for 1 hour;

[0048] Neutralization: add 1.2% sodium formate, rotate for 20 minutes; add 1.6% baking soda, rotate for 1 hour, and measure the pH value at 5.0-5.2;

[0049] Filling: add 3% of melamine resin DLF (Stahl Fine Coatings Co., Ltd.), 3% of dicyandiamide resin R19 (Taige Chemical Co., Ltd.), 2% of acrylic resin R 83 (Temper Chemical Co., Ltd.), rotate for 90 minutes, and drain;

[0050] Dyeing: add 50% water, 1.2% dye, rotate for 60 minutes; add 1% formic acid, rotate for 20 minutes;

[0051] Fat-liquoring: add 100% water, temperature 50°C, add 8% synthetic oil 94S (Sima Chemical Co., Ltd.), 4% sulfited fish oil MIR 90 (Yixiang Chemical Co., Ltd.), rotate for 60 minutes; add 1.5% formic acid, rotate for 30 minutes;

[0052] The antibacterial leather crust is obtained by washing, drumming, stretching, vacuuming and drying.

[0053] Implementation effect:

[0054] The leather was tested according to the standard "QB / T 2881-2013 Technical Conditions for Antibacterial Performance of Footwear and Footwear Components", the chromium content of the waste liquid was determined by the sodium chromate colorimetric method, and the amount of chrome tanning agent and dye was calculated based on actual use. The results are shown in the table below.

[0055] Crust leather performance testing

[0056]

[0057] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A method for preparing an antibacterial retanning agent, characterized in that: The steps include: 1) Dissolve the rare earth oxide La2O3 in hydrochloric acid with a concentration of 1:1, evaporate to near dryness, and obtain the rare earth chloride LaCl3·6H2O; 2) Add 10 mmol of o-phenanthroline to 40-60 mL of anhydrous ethanol solution containing 10 mmol of LaCl3·6H2O, stir until a milky white precipitate is generated, and react for 1-2 hours; 3) Then add 40-60 mL of anhydrous ethanol solution of 30 mmol methacrylic acid dropwise, the mixture becomes clear, and the reaction is continued, and a precipitate is generated; 4) After 5-6 hours of reaction, centrifuge and wash the precipitate several times with anhydrous ethanol and place it in P4O 10 The mixture was dried in a vacuum dryer to a constant weight to obtain the antibacterial retanning agent rare earth organic complex La(C3H5CO2)3(Phen).

2. A wet dyeing and finishing process for antibacterial leather, characterized in that: The process includes the following steps: wet blue leather → squeezing, shaving → softening → retanning → neutralization → filling → dyeing → fatliquoring → washing, drumming → stretching, vacuuming, drying → antibacterial leather crust; Wherein, for retanning, 100% water and 2% chrome tanning agent are added and the mixture is rotated for 2 hours; 1% to 3% of the antibacterial retanning agent rare earth organic complex as claimed in claim 1 is added and the mixture is rotated for 1 hour.

3. The wet dyeing and finishing process of antibacterial leather according to claim 2, characterized in that: The wet blue leather is squeezed and shaving: the wet blue leather is squeezed to control the moisture content to about 40%, and the shaving thickness is 1.2 mm.

4. The wet dyeing and finishing process of antibacterial leather according to claim 2, characterized in that: The softening process is as follows: wet blue leather is put into a rotary drum, 200% water, 0.3% oxalic acid and 0.3% rewetting agent OC are added, and the drum is rotated for 2 hours, so that the whole wet blue leather is thoroughly rehydrated, the leather body is soft, and the water is drained.

5. The wet dyeing and finishing process of antibacterial leather according to claim 2, characterized in that: The neutralization: add 1.2% sodium formate, rotate for 20 minutes; add 1.6% baking soda, rotate for 1 hour, and measure the pH value at 5.0-5.

2.

6. The wet dyeing and finishing process for antibacterial leather according to claim 2, characterized in that: The filling process includes adding 3% melamine resin DLF, 3% dicyandiamide resin R19, and 2% acrylic resin R83, rotating for 90 minutes, and draining the water.

7. The wet dyeing and finishing process for antibacterial leather according to claim 2, characterized in that: The dyeing process includes adding 50% water and 1.2% dye and rotating for 60 minutes; adding 1% formic acid and rotating for 20 minutes.

8. The wet dyeing and finishing process for antibacterial leather according to claim 2, characterized in that: The fatliquoring process comprises the following steps: adding 100% water, setting the temperature to 50°C, adding 8% of synthetic oil 94S, 4% of sulfited fish oil MIR90, and rotating for 60 minutes; adding 1.5% of formic acid, and rotating for 30 minutes.

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