Zeolite-based dyeing-free white nappa leather manufacturing process

Abstract

The invention relates to a zeolite-based dyeing-free white nappa leather manufacturing process, which comprises the following steps: rewetting, neutralization (1), retanning (1), retanning (2), neutralization (2), filling and drying finishing, in the retanning (1) process, a small-molecular acrylic resin tanning agent is added, and in the filling process, the small-molecular acrylic resin tanning agent is added; a zeolite tanning agent is added in the second retanning procedure, and electrolyte oil is resisted; and modified sulfonate, silicon-containing grease and synthetic waterproof oil are added in the filling process. Zeolite serves as a natural mineral tanning agent, does not contain heavy metal and other harmful substances, replaces traditional chrome tanning and other processes, and reduces environmental pollution through dyeing-free treatment. Through zeolite tanning and subsequent process treatment, the softness of the nappa leather is remarkably improved, the average value of the softness can reach 4.0 or above, and the leather is finer and more comfortable in touch feeling; the nappa leather is easy to fade and age after being exposed to the sun for a long time, and the nappa leather has light resistance and can keep long-term color brightness and attractive appearance by selecting a material with good light resistance in the process.

Description

Technical Field

[0001] The invention relates to the technical field of leather manufacturing, in particular to a zeolite-based non-dyed white nappa leather manufacturing process. Background Art

[0002] With the increasing awareness of environmental protection around the world, the traditional leather industry is facing unprecedented transformation pressure and unprecedented innovation opportunities. For a long time, traditional leather manufacturing has been highly dependent on chrome tanning, which can give leather excellent thermal stability, comfortable feel and excellent leather properties, and occupies an absolute dominant position in the leather industry. However, the accompanying chromium ion emission problem has caused serious pollution to water bodies and soil, and the harmful chemicals in the production process may also affect human health through direct or environmental contact, posing a potential threat that cannot be ignored. Therefore, environmentally friendly, efficient and sustainable leather production technology has become the focus of industry research and development.

[0003] In view of this, the inventor conducted in-depth research on the above-mentioned issues, and thus the present case was produced. Summary of the invention

[0004] The invention provides a zeolite-based non-dyed white nappa leather manufacturing process to overcome the problem that harmful substances in the existing leather production process affect human health.

[0005] The present invention adopts the following technical solution:

[0006] A zeolite-based undyed white nappa leather manufacturing process comprises the following steps: rewetting → neutralization ① → retanning ① → retanning ② → neutralization ② → filling → drying and finishing, wherein:

[0007] Retanning①: add 50%-100% water and 1.0%-3.0% synthetic oil to the drum, rotate at 35°C for 20 minutes; add 1.0%-3.0% medium molecular acrylic resin tanning agent and 1.0%-5.0% medium and small molecular acrylic resin tanning agent, rotate for 60 minutes; add 2.0%-3.0% light-resistant resin tanning agent, 2.0%-6.0% melamine resin tanning agent and 2.0%-5.0% melamine resin tanning agent, rotate for 90 minutes; add 100% water at 35°C and rotate for 10 minutes; add 1.0%-1.6% formic acid twice, rotate for 20-30 minutes each time, adjust the pH of the bath liquid to less than 3.7, drain the liquid, and wash with water;

[0008] In the retanning process①, small and medium molecular acrylic resin tanning agents are added, and in the filling process, small molecular acrylic resin tanning agents are added:

[0009] (1) Enhance the physical properties of leather: acrylic resin tanning agents of different molecular weights have different permeability and binding abilities in leather. High molecular weight acrylic resin tanning agents tend to form a protective film on the surface of leather, while low molecular weight acrylic resin tanning agents are more likely to penetrate into the leather and bind to leather fibers, thereby improving the overall performance of the leather.

[0010] (2) Improve the appearance and feel of leather: The application of acrylic resin tanning agent can make the leather surface smoother and more delicate, and improve the grade and beauty of the leather. At the same time, the softness of the resin also helps to improve the feel of the leather, making it softer and more comfortable.

[0011] (3) No dyeing effect: Acrylic resin itself does not provide color, so it will not affect the whiteness of the leather. On the contrary, adding it at the end of the filling can serve as a protective layer to prevent the leather from changing color or fading during subsequent processing or use.

[0012] Retanning②: add 100%-150% water, 1.0%-1.5% modified glutaraldehyde, 1.0%-3.0% electrolyte oil into the drum, the temperature is 35°C, and the drum is rotated for 20 minutes; add 1.0%-3.0% formic acid, rotate for 15 minutes; add 2.0%-5.0% zeolite tanning agent, rotate for 90 minutes; add 1.0%-1.5% sodium formate, rotate for 30 minutes; add 0.5%-1.0% baking soda, adjust the bath liquid to 3.8≤pH≤4.2, and drain;

[0013] Zeolite tanning agent is added in the retanning step ②:

[0014] (1) It can react with the carboxyl groups on the side chains of the collagen fibers in the leather. As the amount of zeolite tanning agent increases, the number of carboxyl groups involved in the coordination also increases accordingly, which enhances the cross-linking and stability between the leather fibers, thereby improving its ability to resist shrinkage deformation caused by a hot and humid environment.

[0015] (2) During the tanning process, zeolite tanning agents can penetrate deeply into the leather and react chemically with the collagen in the leather to form a stable cross-linked structure. This cross-linked structure not only enhances the structural stability of the leather, thereby exhibiting the best physical and mechanical properties, but also further improves the softness and toughness of the leather by optimizing the arrangement and gap distribution of the fibers inside the leather. In addition, the use of zeolite tanning agents can also effectively reduce the evaporation and shrinkage of the leather during subsequent processing, which is crucial to maintaining the softness of the leather.

[0016] (3) Compared with traditional chrome tanning agents, zeolite tanning agents have better environmental performance. They do not contain harmful substances such as heavy metals and will not pollute the environment. At the same time, zeolite can also absorb excess moisture, impurities and harmful substances in leather, reduce the use of chemical tanning agents, thereby reducing environmental pollution at the source and is easy to handle.

[0017] Filling: add 50% to 100% water, 1.0% to 1.8% light-resistant synthetic oil, 1.0% to 3.0% silicone grease into the drum, the temperature is 35°C, and the drum is rotated for 30 minutes; add 2.0% to 6.0% macromolecular acrylic resin tanning agent, 1.0% to 5.0% light-resistant synthetic tanning agent, and rotate for 60 minutes; add 1.0% to 3.0% replacement tannin, 2.0% to 6.0% melamine resin tanning agent, 1.0% to 5.0% melamine resin tanning agent, 2.0% to 6.0% modified sulfonate, 2.0% to 6.0% light-resistant synthetic tanning agent, and rotate for 12 minutes. 0min; add 200% water at 55℃, rotate for 10min; add 1.0%~1.5% silicone grease, 1.0%~5.0% light-resistant synthetic oil, 1.0%~1.5% high-concentration phospholipids, 2.0%~5.0% synthetic waterproof oil, rotate for 60min, add 1.0%~3.0% small molecule acrylic resin tanning agent, rotate for 40min; add 1.5~3.2% formic acid in four times, rotate for 15min each time, adjust 3.6≤pH≤3.8, add 1.0%~1.5% cationic oil, rotate for 10min, drain the liquid, and wash out the drum with water.

[0018] Modified sulfonates, silicone-containing greases, and synthetic waterproof oils are added during the filling process: (1) Modified sulfonates are a functional additive that can enhance the waterproof properties of leather. Their special chemical structure helps to form a waterproof film on the leather surface, effectively blocking water penetration. (2) Silicone oil has good waterproof properties and can form a protective film on the leather surface to prevent water and stains from penetrating, thereby improving the water resistance and washability of the leather. (3) Synthetic waterproof oil has a better waterproof effect than general greases, further enhancing the waterproof properties of leather.

[0019] Electrolyte-resistant oil is added in the retanning process ②: The electrolyte-resistant property of electrolyte-resistant oil helps it to better penetrate and combine between leather fibers, ensuring even distribution of oil and improving the overall effect.

[0020] Retanning①. Melamine resin retanning agent is added in the filling process: Melamine resin retanning agent has excellent filling performance and can be filled in large quantities between the collagen fibers of leather, making the leather grain fine, the body full, and the thickening effect obvious. By combining with the multi-site of the leather collagen fibers, it gives the leather better elasticity and firmness, and improves the overall texture of the finished leather. At the same time, it has good light resistance, which helps to improve the weather resistance of the leather and extend its service life. Adding melamine resin retanning agent in the filling process can further fill the gaps between the leather fibers, making the leather more compact and full.

[0021] Further, the above neutralization ①: add 100% to 150% water, 2.0% to 6.0% neutralizer, 0.5% to 1.0% sodium formate, 0.1% to 1.5% baking soda to the drum, the temperature is 35°C, and rotate for 40 minutes; add 0.5% to 1.0% synthetic oil, rotate for 60 minutes, adjust the bath liquid to 4.8≤pH≤5.2, and drain.

[0022] Further, the above neutralization ②: add 100% to 150% water, 2.0% to 6.0% neutralizer, 0.5% to 1.0% sodium formate, 0.5% to 1.0% baking soda to the drum, the temperature is 35°C, rotate for 40 minutes, adjust 4.8≤pH≤5.0; add 0.1% to 1.5% light-resistant synthetic oil, rotate for 60 minutes, drain the liquid, and wash with water.

[0023] Furthermore, the above drying finishing: standing for 12 hours → squeezing water and stretching → vacuum drying (40°C / 300s) → hanging to dry → drying → moisture regain → standing → vibration and softening.

[0024] 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:

[0025] 1. Has remarkable environmental protection performance

[0026] Zeolite tanning agent: Zeolite, as a natural mineral tanning agent, does not contain harmful substances such as heavy metals. It replaces traditional chrome tanning processes and reduces environmental pollution.

[0027] Non-dyeing treatment: The non-dyeing process reduces the use of chemical dyes, reduces the difficulty of wastewater treatment and the risk of environmental pollution, and conforms to modern environmental protection concepts.

[0028] 2. Optimize the physical properties of leather

[0029] Softness: Through zeolite tanning and subsequent processing, the softness of Nappa leather has been significantly improved, with an average value of over 4.0, making the leather feel more delicate and comfortable.

[0030] Moisture and heat resistance stability: Enhances the moisture and heat resistance of leather, improves its ability to resist shrinkage and deformation caused by a humid and hot environment, and can reach above 85°C, ensuring the stability and durability of the leather under different climatic conditions.

[0031] Light resistance: Leather is prone to fading and aging when exposed to sunlight for a long time. The process uses materials with good light resistance to make Nappa leather light-resistant, which can maintain its color brightness and beautiful appearance for a long time.

[0032] Waterproofing: The process includes a waterproofing step, which makes the undyed white nappa leather water-resistant to the point of resisting water penetration. DETAILED DESCRIPTION

[0033] In order to better understand the above technical scheme, the above technical scheme will be described in detail below in combination with the specification and the specific implementation method (the amount of chemical materials used in the rewetting, neutralization ①, retanning ①, retanning ②, neutralization ② and filling processes are all based on the weight of the white wet leather after shaving. For example, the weight of the white wet leather after shaving is 100kg, then 300% water is 300kg water).

[0034] Embodiment 1:

[0035] A process for manufacturing undyed white nappa leather based on zeolite, comprising the following process steps:

[0036] Rewetting: put the shaved wet leather into a drum, add 300% water, 3.0% oxalic acid, 0.5% surfactant (BORRON SAF, De Ruipi Chemical Co., Ltd.), 6.0% salt into the drum, the temperature is 50°C, rotate for 90 minutes, adjust the bath pH ≤ 3.0, drain the liquid, and wash with water.

[0037] Neutralization ①: add 150% water, 2.0% neutralizer (Tamol X NL, BASF AG), 1.0% sodium formate, 0.5% baking soda into the drum, the temperature is 35°C, and the drum is rotated for 40 minutes; add 1.0% synthetic oil (CORIPOL SLG, De Ruipi Chemical Co., Ltd.), rotate for 60 minutes, adjust the bath liquid to 4.8≤pH≤5.2, and drain.

[0038] Retanning①: add 50% water and 2.0% synthetic oil to the drum, set the temperature to 35°C, and rotate for 20 minutes; add 3.0% medium-molecular acrylic resin tanning agent (VTAN C30, Shanghai Laitan New Material Technology Co., Ltd.) and 3.0% small-molecular acrylic resin tanning agent (BITAN B4, UNITEK) and rotate for 60 minutes; add 3.0% light-resistant resin tanning agent (TRUPOTAN BIO-08P, Tompler Chemical Dye (Jiaxing) Co., Ltd.), 3.0% melamine resin tanning agent (TRUPOTAN HB, Tompler Chemical Dye (Jiaxing) Co., Ltd.) and 2.0% melamine resin tanning agent (BITAN R19, UNITEK) and rotate for 90 minutes; add 100% water at 35°C and rotate for 10 minutes; add 1.6% formic acid twice, rotate for 20 minutes each time, adjust the pH of the bath liquid to less than 3.7, drain the liquid, and wash with water.

[0039] Retanning②: add 150% water, 1.5% modified glutaraldehyde (BESTAN WG 60, BESTAN), 1.0% electrolyte resistant oil (PELLAN GLH liq, Kekai Fine Chemicals (Shanghai) Co., Ltd.) into the drum, temperature 35°C, rotate for 20 min; add 0.5% formic acid, rotate for 15 min; add 5.0% zeolite tanning agent (UNITEK), rotate for 90 min; add 1.0% sodium formate, rotate for 30 min; add 0.5% baking soda, adjust the bath liquid to 3.8≤pH≤4.2, and drain.

[0040] Neutralization ②: add 150% water, 2.0% neutralizer, 1.0% sodium formate, 0.5% baking soda to the drum, rotate at 35°C for 40 minutes, adjust to 4.8≤pH≤5.0; add 1.0% light-resistant synthetic oil (TANINOIL BQ, Chengdu Pengzhou Mingzhong Chemical Co., Ltd.), rotate for 60 minutes, drain and wash with water.

[0041] Filling: add 50% water, 1.0% light-resistant synthetic oil, 1.0% silicone grease (TJ-F5193, Sichuan Tingjiang New Materials Co., Ltd.) to the drum, the temperature is 35°C, and the drum is rotated for 30 minutes; add 3.0% macromolecular acrylic resin tanning agent (BAYTIGANAR, De Ruipi Chemical Co., Ltd.), 3.0% light-resistant synthetic tanning agent (DRASIL 608 / C, Kekai Fine Chemicals (Shanghai) Co., Ltd.) and rotate for 60 minutes; add 1.5% replacement tannin (TANIGAN OSR, De Ruipi Chemical Co., Ltd.), 3.0% melamine resin tanning agent, 0.0% melamine resin tanning agent, and modified sulfonate (BLX 14468, BUCKMAN Company) 4.0%, light-resistant synthetic tanning agent) 4.0%, rotate for 120 minutes; add 200% of 55°C water, rotate for 10 minutes; add 1.5% of silicone grease (TJ-F5193, Sichuan Tingjiang New Materials Co., Ltd.), 2.0% of light-resistant synthetic oil, 1.5% of high-concentration phospholipids (TRUPON DB, Temple Chemical Dye (Jiaxing) Co., Ltd.), 2.0% of synthetic waterproof oil (PERFECTOL QX, SCHILL+SEILACHER Company), rotate for 60 minutes, add 2.0% of small molecule acrylic resin tanning agent (INTAN TP 340, ALPA Company), rotate for 40 minutes; add 2.4% of formic acid in four times, rotate for 15 minutes each time, adjust 3.6≤pH≤3.8, add 1.0% of cationic oil (XGS, Sichuan Tingjiang New Materials Co., Ltd.), rotate for 10 minutes, drain the liquid, and wash the drum with water.

[0042] Drying and finishing: let stand for 12 hours → squeeze out water and stretch → vacuum drying (40℃ / 300s) → hang to dry → dry → regain moisture → let stand → oscillate and soften.

[0043] Embodiment 2:

[0044] A process for manufacturing undyed white nappa leather based on zeolite, comprising the following process steps:

[0045] Rewetting: put the shaved wet leather into a drum, add 300% water, 3.0% oxalic acid, 0.5% surfactant (BORRON SAF, De Ruipi Chemical Co., Ltd.), 6.0% salt into the drum, the temperature is 50°C, rotate for 90 minutes, adjust the bath pH ≤ 3.0, drain the liquid, and wash with water.

[0046] Neutralization ①: Add 150% water, 2.0% neutralizer, 0.5% sodium formate, 1.5% baking soda into the drum, temperature 35°C, rotate for 40 minutes; add 1.0% synthetic oil, rotate for 60 minutes, adjust the bath liquid to 4.8≤pH≤5.2, and drain.

[0047] Retanning①: Add 50% water and 1.0% synthetic oil into the drum, temperature 35℃, rotate for 20min; add 3.0% medium molecular acrylic resin tanning agent and 1.0% medium and small molecular acrylic resin tanning agent, rotate for 60min; add 2.0% light-resistant resin tanning agent, 4.0% melamine resin tanning agent and 2.0% melamine resin tanning agent, rotate for 90min; add 100% water at 35℃, rotate for 10min; add 1.6% formic acid twice, rotate for 20-30min each time, adjust the pH of the bath liquid to less than 3.7, drain the liquid, and wash with water.

[0048] Retanning②: add 150% water, 1.0% modified glutaraldehyde, 3.0% electrolyte oil into the drum, rotate at 35°C for 20 minutes; add 3.0% formic acid, rotate for 15 minutes; add 5.0% zeolite tanning agent, rotate for 90 minutes; add 1.0% sodium formate, rotate for 30 minutes; add 0.5% baking soda, adjust the bath liquid to 3.8≤pH≤4.2, and drain.

[0049] Neutralization ②: Add 150% water, 2.0% neutralizer, 0.5% sodium formate, 1.0% baking soda into the drum, temperature 35°C, rotate for 40 minutes, adjust 4.8≤pH≤5.0; add 1.5% light-resistant synthetic oil, rotate for 60 minutes, drain and wash with water.

[0050] Filling: add 50% water, 1.8% light-resistant synthetic oil, 1.0% silicone grease into the drum, rotate at 35°C for 30 minutes; add 6.0% macromolecular acrylic resin tanning agent, 2.0% light-resistant synthetic tanning agent, rotate for 60 minutes; add 1.5% replaced tannin, 2.0% melamine resin tanning agent, 3.0% melamine resin tanning agent, 3.0% modified sulfonate, 2.0% light-resistant synthetic tanning agent, rotate for 120 minutes; add 200% water at 55°C, rotate for 10 minutes; add 1.5% silicone grease, 1.0% light-resistant synthetic oil, 1.5% high-concentration phospholipids, 4.0% synthetic waterproof oil, rotate for 60 minutes, add 2.0% small molecular acrylic resin tanning agent, rotate for 40 minutes; add 2.6% formic acid in four times, rotate for 15 minutes each time, adjust 3.6≤pH≤3.8, add 1.5% cationic oil, rotate for 10 minutes, drain the liquid, and wash out the drum with water.

[0051] Drying and finishing: let stand for 12 hours → squeeze out water and stretch → vacuum drying (40℃ / 300s) → hang to dry → dry → regain moisture → let stand → oscillate and soften.

[0052] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited to this. 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 process for producing undyed white nappa leather based on zeolite, characterized in that: The method comprises the following steps: rewetting→neutralization①→retanning①→retanning②→neutralization②→filling→drying and finishing, wherein, retanning①: add 50% to 100% water and 1.0% to 3.0% synthetic oil into a drum, rotate at a temperature of 35°C for 20 minutes; add 1.0% to 3.0% medium-molecular acrylic resin tanning agent and 1.0% to 5.0% medium-molecular acrylic resin tanning agent, rotate for 60 minutes; add 2.0% to 3.0% light-resistant resin tanning agent, 2.0% to 6.0% melamine resin tanning agent and 2.0% to 5.0% melamine resin tanning agent, rotate for 90 minutes; add 100% water at 35°C and rotate for 10 minutes; add 1.0% to 1.6% formic acid twice, rotate for 20 to 30 minutes each time, adjust the pH value of the bath liquid to less than 3.7, drain the liquid, and wash with water; Retanning②: add 100% to 150% water, 1.0% to 1.5% modified glutaraldehyde, 1.0% to 3.0% electrolyte oil into the drum, the temperature is 35°C, and the drum is rotated for 20 minutes; add 1.0% to 3.0% formic acid, rotate for 15 minutes; add 2.0% to 5.0% zeolite tanning agent, rotate for 90 minutes; add 1.0% to 1.5% sodium formate, rotate for 30 minutes; add 0.5% to 1.0% baking soda, adjust the bath liquid to 3.8≤pH≤4.2, and drain; filling: add 50% to 100% water, 1.0% to 1.8% light-resistant synthetic oil, 1.0% to 3.0% silicone grease into the drum, the temperature is 35°C, and the drum is rotated for 30 minutes; add 2.0% to 6.0% macromolecular acrylic resin tanning agent, 1.0% to 5.0% light-resistant synthetic tanning agent, rotate for 60 minutes; add place Replace tannin 1.0%-3.0%, melamine resin tanning agent 2.0%-6.0%, melamine resin tanning agent 1.0%-5.0%, modified sulfonate 2.0%-6.0%, light-resistant synthetic tanning agent 2.0%-6.0%, rotate for 120 minutes; add 200% of 55°C water, rotate for 10 minutes; add silicone grease 1.0%-1.5%, light-resistant synthetic oil 1.0%-5.0%, high-concentration phospholipids 1.0%-1.5%, synthetic waterproof oil 2.0%-5.0%, rotate for 60 minutes, add small molecule acrylic resin tanning agent 1.0-3.0%, rotate for 40 minutes; add formic acid 1.5-3.2% in four times, rotate for 15 minutes each time, adjust 3.6≤pH≤3.8, add cationic oil 1.0%-1.5%, rotate for 10 minutes, drain the liquid, and wash out the drum with water.

2. A process for manufacturing undyed white nappa leather based on zeolite as claimed in claim 1, characterized in that: The neutralization ①: add 100% to 150% water, 2.0% to 6.0% neutralizer, 0.5% to 1.0% sodium formate, 0.1% to 1.5% baking soda into the drum, the temperature is 35°C, and the drum is rotated for 40 minutes; add 0.5% to 1.0% synthetic oil, rotate for 60 minutes, adjust the bath liquid to 4.8≤pH≤5.2, and drain.

3. A process for manufacturing undyed white nappa leather based on zeolite as claimed in claim 1, characterized in that: The neutralization ②: add 100% to 150% water, 2.0% to 6.0% neutralizer, 0.5% to 1.0% sodium formate, 0.5% to 1.0% baking soda into the drum, the temperature is 35°C, rotate for 40 minutes, adjust 4.8≤pH≤5.0; add 0.1% to 1.5% light-resistant synthetic oil, rotate for 60 minutes, drain and wash with water.

4. A process for manufacturing undyed white nappa leather based on zeolite as claimed in claim 1, characterized in that: The drying and finishing process includes: standing for 12 hours → squeezing out water and stretching → vacuum drying (40°C / 300s) → hanging to dry → drying → moisture regaining → standing → oscillating and softening.