Preparation method of rare earth zeolite tanning agent and plant-rare earth zeolite combined tanning process

Abstract

The invention relates to a preparation method of a rare earth zeolite tanning agent, which comprises the following steps of: dissolving rare earth oxide in hydrochloric acid with the ratio of 1: 1, and evaporating until the rare earth oxide is nearly dry; the preparation method comprises the following steps: respectively dissolving L-phenylalanine and 1, 10-o-phenanthroline in an ethanol aqueous solution, adding a LaCl3. 6H2O ethanol aqueous solution, carrying out water bath reflux for 6 hours, and standing overnight; evaporating in a water bath, precipitating and crystallizing, washing with acetone, drying, adding zeolite, mixing, and grinding into powder, so as to prepare a rare earth zeolite tanning agent; a plant-rare earth zeolite combined tanning technology comprises the following procedures of normal mass production of pickled bare leather, fatty aldehyde pre-tanning, vegetable tanning, rare earth zeolite tanning agent combined tanning, alkali extraction, water washing, drum discharging, horse building and standing, and vegetable tanning of white wet leather. The natural plant tanning agent does not contain heavy metals, formaldehyde, benzene, phenol and other harmful components, and has the advantages of no toxicity, small pollution, biodegradability and the like; the plant-rare earth zeolite cooperates with the tanning effect, so that the shrinkage temperature is greatly increased, and the mechanical property and the sensory property are improved.

Description

Technical Field

[0001] The invention relates to the technical field of leather manufacturing, in particular to a preparation method of a rare earth zeolite tanning agent and a plant-rare earth zeolite combined tanning process. Background Art

[0002] Tanning, as the core link of the leather making process, is centered on the deep integration of skin collagen fibers and tanning agents to achieve a qualitative change from skin to leather. Since Friedrich Knapp revealed the tanning properties of chromium in 1858, chrome tanning has long dominated the leather making industry by giving leather excellent resistance to moisture and heat, water washing, and excellent extensibility, softness and full elasticity. However, this traditional process has significant drawbacks: low chromium utilization (only 65%-75%), resulting in serious waste of resources and environmental pollution, unbound Cr (III) may be converted into highly toxic Cr (VI), endangering human health and ecological safety; in addition, chrome tanned leather is difficult to degrade naturally, which aggravates environmental pressure. In addition, the scarcity and uneven distribution of chromium resources, as well as the secondary pollution of the environment caused by the large-scale use of neutral salts in traditional processes, all pose major challenges to the sustainable development of the industry.

[0003] Vegetable tanning, as an ancient and environmentally friendly tanning method, has many advantages: ① Environmental protection: Vegetable tanned leather contains only pure natural animal and plant ingredients, does not contain heavy metals, benzene, phenol and other harmful ingredients, and conforms to modern environmental protection concepts; ② Naturalness: Vegetable tanned leather retains the grain and gloss of the leather itself, is naturally simple, and has a unique texture and color; ③ Wearability: With the improvement of leather making technology, the feel and wearability of vegetable tanned leather have been significantly improved. It has good air permeability and moisture absorption and is comfortable to wear; ④ Plasticity: Vegetable tanned leather has good plasticity in a wet state, which is convenient for various shapes and designs.

[0004] Although vegetable tanned leather has many advantages, it also has some disadvantages that cannot be ignored: ① Low shrinkage temperature: The shrinkage temperature of vegetable tanned leather is relatively low, generally only more than 70 degrees, which means that in a high temperature environment, its dimensional stability is poor and it is easy to deform; ② Easy to grow mold: Because vegetable tanned leather contains more natural ingredients and has a loose fiber structure, it is easy to breed mold. In a humid environment, if it is not properly maintained, vegetable tanned leather is prone to mold and deterioration, affecting its appearance and service life. Summary of the invention

[0005] In order to overcome the above problems, the present invention provides a method for preparing a rare earth zeolite tanning agent and a plant-rare earth zeolite combined tanning process, which significantly enhances the tanning effect while maintaining the excellent properties of vegetable tanned leather, greatly improves the shrinkage temperature of vegetable tanned white wet leather, and at the same time gives the vegetable tanned white wet leather good antibacterial properties.

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

[0007] A method for preparing a rare earth zeolite tanning agent comprises the following steps:

[0008] 1) dissolving rare earth oxide La2O3 (purity>99.9%) in hydrochloric acid with a concentration ratio of 1:1, evaporating to near dryness, and obtaining rare earth chloride LaCl3·6H2O;

[0009] 2) Dissolve 0.15 mol L-phenylalanine (Phe) and 0.05 mol 1,10-phenanthroline (Phen) in 500 ml ethanol-water solution respectively, mix the two and heat them in a water bath, add 0.05 mol LaCl3·6H2O in 500 ml ethanol-water solution when the solution boils, reflux in a water bath for 6 hours, and let stand overnight;

[0010] 3) Evaporating in a water bath until it becomes viscous, precipitating and crystallizing, washing with acetone, and drying to obtain a rare earth organic complex La(Phe)3PhenCl3·3H2O;

[0011] 4) Add zeolite in a mass ratio of 1:4, mix and grind into powder to obtain a rare earth zeolite tanning agent.

[0012] A plant-rare earth zeolite combined tanning process, comprising the following steps: normal mass production pickling bare leather → fatty aldehyde pre-tanning → vegetable tanning → rare earth zeolite tanning agent combined tanning La(Phe)3PhenCl3·3H2O → alkali extraction → washing, drumming, horse riding, standing → vegetable tanned white wet leather; the details are as follows:

[0013] The rotary drum is put into large-scale production to pickle bare leather, control the pickling liquid ratio to 50%, add 2% of fatty aldehyde PF (Sima Chemical (China) Co., Ltd.), rotate for 60 minutes; add 1% of sodium formate, rotate for 15 minutes, add 1% of baking soda, rotate for 50 minutes, measure the pH value at 4.0-4.2, and drain; add 30% of water, 2% of fish oil MIR90, rotate for 30 minutes; add 10%-25% of vegetable tannin ATO (Shihua Technology Co., Ltd.), rotate for 5-8 hours; add 4%-6% of rare earth zeolite tanning agent, rotate for 2-3 hours; add 1% of sodium formate, rotate for 15 minutes, add 1.5% of baking soda, rotate for 60 minutes, measure the pH value at 4.8-5.0, and drain; wash with water, remove from the drum, mount, and let stand to obtain vegetable tanned white wet leather.

[0014] 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:

[0015] 1. Rare earth ions, L-phenylalanine, and o-phenanthroline all have certain antibacterial properties, and the antibacterial activity of the complexes they form is better than that of single ligands and rare earth ions. This is mainly due to the synergistic effect between rare earth ions and ligands. They have good antibacterial effects at low concentrations and do not produce drug resistance. They are less toxic than many traditional antibacterial organic synthetics or transition metal complexes.

[0016] 2. Rare earth elements have unique electronic structures and chemical properties. They react chemically with leather collagen fibers to form stable chemical bonds. The formation of these chemical bonds strengthens the binding force between leather fibers, plays a tanning role, and makes the leather stronger and more durable. The distribution of rare earth elements in leather also plays a certain physical filling role, making the leather structure more compact, thereby increasing 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.), they will produce a synergistic effect. This synergistic effect can further enhance the performance of the leather, such as improving the softness, fullness and elasticity of the leather.

[0017] 3. Zeolite is a hydrated aluminosilicate of alkali metal or alkaline earth metal with silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron structures. It reacts with leather collagen fibers and vegetable tanning agents to form an interpenetrating network structure, which enhances the binding force between the tanning agent and leather collagen. The resulting leather's resistance to water washing, resistance to organic solvents and shrinkage temperature are greatly improved, reflecting a good synergistic tanning effect.

[0018] 4. Natural vegetable tanning, does not contain heavy metals, formaldehyde, benzene, phenol and other harmful ingredients, and has the advantages of non-toxic, low pollution and biodegradable.

[0019] 5. The plant-rare earth zeolite synergistic tanning effect greatly increases the shrinkage temperature and improves the mechanical and sensory properties; it gives the vegetable tanned wet white leather good antibacterial properties and can be stored for 3 months without mold. DETAILED DESCRIPTION

[0020] Embodiment 1:

[0021] Preparation of rare earth zeolite tanning agent:

[0022] The rare earth oxide La2O3 (purity> 99.9%) is dissolved in hydrochloric acid with a concentration ratio of 1:1, and evaporated to near dryness to obtain rare earth chloride (LaCl3·6H2O). 0.15mol L-phenylalanine (Phe) and 0.05mol 1,10-phenanthroline (Phen) are respectively dissolved in 500ml ethanol aqueous solution, the two are mixed and heated on a water bath, and when the solution boils, 0.05mol LaCl3·6H2O 500ml ethanol aqueous solution is added, the water bath is refluxed for 6h, and the mixture is allowed to stand overnight. The mixture is evaporated in a water bath until it becomes viscous, and crystals are precipitated and washed with acetone and dried to obtain a rare earth organic complex La(Phe)3PhenCl3·3H2O, and then zeolite is added in a mass ratio of 1:4, mixed and ground into powder to obtain a rare earth zeolite tanning agent.

[0023] A plant-rare earth zeolite combined tanning process, comprising the following steps: normal mass production pickling bare leather → fatty aldehyde pre-tanning → vegetable tanning → rare earth zeolite tanning agent combined tanning La(Phe)3PhenCl3·3H2O → alkali extraction → washing, drumming, horse riding, standing → vegetable tanned white wet leather; the details are as follows:

[0024] The rotary drum is put into large-scale production to pickle bare leather, control the pickling liquid ratio to 50%, add 2% of fatty aldehyde PF (Sima Chemical (China) Co., Ltd.), rotate for 60 minutes; add 1% of sodium formate, rotate for 15 minutes, add 1% of baking soda, rotate for 50 minutes, measure the pH value at 4.0-4.2, and drain; add 30% of water, 2% of fish oil MIR90, rotate for 30 minutes; add 15% of vegetable tannin ATO (Shihua Technology Co., Ltd.), rotate for 6 hours; add 5% of rare earth zeolite tanning agent, rotate for 2 hours; add 1% of sodium formate, rotate for 15 minutes, add 1.5% of baking soda, rotate for 60 minutes, measure the pH value at 4.8-5.0, and drain; wash with water, remove from the drum, mount, and let stand to obtain vegetable tanned white wet leather.

[0025] Embodiment 2:

[0026] Preparation of rare earth zeolite tanning agent:

[0027] The rare earth oxide La2O3 (purity> 99.9%) is dissolved in hydrochloric acid with a concentration ratio of 1:1, and evaporated to near dryness to obtain rare earth chloride (LaCl3·6H2O). 0.15mol L-phenylalanine (Phe) and 0.05mol 1,10-phenanthroline (Phen) are respectively dissolved in 500ml ethanol aqueous solution, the two are mixed and heated on a water bath, and when the solution boils, 0.05mol LaCl3·6H2O 500ml ethanol aqueous solution is added, the water bath is refluxed for 6h, and the mixture is allowed to stand overnight. The mixture is evaporated in a water bath until it becomes viscous, and crystals are precipitated and washed with acetone and dried to obtain a rare earth organic complex La(Phe)3PhenCl3·3H2O, and then zeolite is added in a mass ratio of 1:4, mixed and ground into powder to obtain a rare earth zeolite tanning agent.

[0028] A plant-rare earth zeolite combined tanning process, comprising the following steps: normal mass production pickling bare leather → fatty aldehyde pre-tanning → vegetable tanning → rare earth zeolite tanning agent combined tanning La(Phe)3PhenCl3·3H2O → alkali extraction → washing, drumming, horse riding, standing → vegetable tanned white wet leather; the details are as follows:

[0029] The rotary drum is put into large-scale production to pickle bare leather, control the pickling liquid ratio to 50%, add 2% of fatty aldehyde PF (Sima Chemical (China) Co., Ltd.), rotate for 60 minutes; add 1% of sodium formate, rotate for 15 minutes, add 1% of baking soda, rotate for 50 minutes, measure the pH value at 4.0-4.2, and drain; add 30% of water, 2% of fish oil MIR90, rotate for 30 minutes; add 20% of vegetable tannin ATO (Shihua Technology Co., Ltd.), rotate for 6 hours; add 6% of rare earth zeolite tanning agent, rotate for 3 hours; add 1% of sodium formate, rotate for 15 minutes, add 1.5% of baking soda, rotate for 60 minutes, measure the pH value at 4.8-5.0, and drain; wash with water, remove from the drum, mount, and let stand to obtain vegetable tanned white wet leather.

[0030] Implementation effect:

[0031] The shrinkage temperature of vegetable tanned wet leather was tested according to the standards QB, T 2713-2005 "Determination of shrinkage temperature of leather in physical and mechanical tests". The antibacterial property was observed by sealing the wet leather (water content 80%) in a plastic bag and placing it in a 37°C incubator. The results are shown in the table below.

[0032] Performance Testing

[0033] Test sample Shrinkage Temperature Antimicrobial properties Example 1 90℃ 3 months, no mold Example 2 91℃ 3 months, no mold Ordinary vegetable tanned wet white leather 72℃ 5 days, mold starts to grow

[0034] 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 a rare earth zeolite tanning agent, characterized in that: The steps include: 1) dissolving rare earth oxide La2O3 in hydrochloric acid at a concentration ratio of 1:1, evaporating to near dryness, and obtaining rare earth chloride LaCl3·6H2O; 2) Dissolve 0.15 mol L-phenylalanine (Phe) and 0.05 mol 1,10-phenanthroline (P hen) in 500 ml ethanol-water solution respectively, mix the two and heat them in a water bath, add 0.05 mol LaCl3·6H2O in 500 ml ethanol-water solution when the solution boils, reflux in a water bath for 6 hours, and let stand overnight; 3) Evaporating in a water bath until it becomes viscous, precipitating and crystallizing, washing with acetone, and drying to obtain a rare earth organic complex La(Phe)3PhenCl3·3H2O; 4) Add zeolite in a mass ratio of 1:4, mix and grind into powder to obtain a rare earth / zeolite tanning agent.

2. A plant-rare earth zeolite combined tanning process, characterized in that: The process includes the following steps: normal large-scale production of pickled leather → fatty aldehyde pre-tanning → vegetable tanning → rare earth zeolite tanning agent combined with tanning La(Phe)3PhenCl3·3H2O as claimed in claim 1 → alkali extraction → washing, drumming, horse riding, standing → vegetable tanned white wet leather; the details are as follows: The rotary drum is put into large-scale production to pickle bare leather, control the pickling liquid ratio to 50%, add 2% fatty aldehyde PF, rotate for 60 minutes; add 1% sodium formate, rotate for 15 minutes, add 1% baking soda, rotate for 50 minutes, measure the pH value at 4.0-4.2, and drain; add 30% water, 2% fish oil MIR90, rotate for 30 minutes; add 10%-25% vegetable tannin ATO, rotate for 5-8 hours; add 4%-6% rare earth zeolite tanning agent, rotate for 2-3 hours; add 1% sodium formate, rotate for 15 minutes, add 1.5% baking soda, rotate for 60 minutes, measure the pH value at 4.8-5.0, and drain; wash with water, remove from the drum, mount and let stand to obtain vegetable tanned white wet leather.