阅读说明：本技术 一种厚型自然摔纹高档沙发革的生产工艺 (Production process of thick natural pattern-falling high-grade sofa leather ) 是由 孙辉永 梁永贤 陈军 温会涛 王小卓 陈永榜 但卫华 于 2019-09-09 设计创作，主要内容包括：本发明涉及制革化学与制革工程技术领域,提供一种厚型自然摔纹高档沙发革的生产工艺,包括如下工序：取厚型蓝湿革依次进行挤水、削匀、称重、回软、前端铬复鞣、中和一、加脂一、中和二、加脂二、填充染色一、加脂三、填充染色二、末端铬复鞣、加脂四、干燥整理、涂饰；本发明的自然摔纹高档沙发革不需要片皮,直接削匀,既可以省去一道工序,又可以明显减少革屑、皮革边角料等废弃物产生量,具有很好的环保效益,并具有良好的撕裂强度、耐磨耐刮擦等物性,提高了皮革的附加值。(The invention relates to the technical field of leather-making chemistry and leather-making engineering, and provides a production process of thick natural pattern-falling high-grade sofa leather, which comprises the following steps: taking thick blue wet leather, sequentially carrying out wringing, shaving, weighing, softening, front end chromium retanning, neutralization I, fatliquoring I, neutralization II, fatliquoring II, filling dyeing I, fatliquoring III, filling dyeing II, tail end chromium retanning, fatliquoring IV, drying, finishing and finishing; the natural grain-broken high-grade sofa leather does not need splitting leather, is directly shaved, can save a process, can obviously reduce the generation amount of wastes such as leather scraps, leather leftover materials and the like, has good environmental protection benefit, has good physical properties such as tearing strength, wear resistance, scraping resistance and the like, and improves the added value of the leather.)

1. A production process of thick natural grain-falling high-grade sofa leather is characterized by comprising the following steps: taking thick blue wet leather, sequentially carrying out wringing, shaving, weighing, softening, front end chromium retanning, neutralization I, fatliquoring I, neutralization II, fatliquoring II, filling dyeing I, fatliquoring III, filling dyeing II, tail end chromium retanning, fatliquoring IV, drying, finishing and finishing;

the softening sequentially comprises surfactant softening, fatting agent softening and enzyme softening;

and adding a zirconium-containing polymetallic tanning agent into both the front-end chromium retanning and the tail-end chromium retanning.

2. The production process of the thick natural falling line high-grade sofa leather according to claim 1, wherein the zirconium-containing multi-metal tanning agent is one or more of a zirconium-aluminum multi-metal complex tanning agent, a chromium-zirconium-aluminum multi-metal complex tanning agent, a zirconium-titanium multi-metal complex tanning agent, a zirconium-aluminum-titanium multi-metal complex tanning agent and a ferrum-zirconium-aluminum multi-metal complex tanning agent.

3. The production process of the thick natural pattern-falling high-grade sofa leather according to claim 1, wherein the surfactant softening step comprises: taking the weight of the blue wet leather obtained by shaving as a reference, putting the shaved blue wet leather into a rotating drum, adding 50-400% of water, adjusting the temperature in the drum to be 25-45 ℃, adding 0-1.0% of formic acid and 0.1-3.0% of surfactant, rotating for 30-120 minutes, and discharging liquid;

the specific steps of softening the fatting agent are as follows: adding 50-400% of water, adjusting the temperature in the drum to 25-45 ℃, adding 0-1.0% of oxalic acid and 0.1-3% of electrolysis-resistant fat-liquoring agent, rotating for 30-120 minutes, and discharging liquid;

the enzyme softening process includes adding water in 50-400 wt% into the drum, regulating the temperature inside the drum to 20-45 deg.c, regulating the pH value of the bath liquid to 3.0-4.6, adding acid softening enzyme in 0.5-6 wt% and electrolyte resisting fatting agent in 0-2 wt%, rotating for 30-300 min and draining.

4. The production process of the thick natural grain-falling high-grade sofa leather according to claim 1, wherein the front-end chrome retanning comprises the following specific steps: adding 50-300% of water into a rotary drum, adjusting the temperature in the drum to be 25-40 ℃, adding 0.5-2% of electrolyte-resistant fatting agent and 0.5-2% of fatty aldehyde, rotating for 20-40 minutes, adding 1-5% of chrome tanning agent, 1-5% of chrome-containing tannin and 0.5-3% of zirconium-containing polymetallic tanning agent, rotating for 30-90 minutes, adding 1-3% of weak organic acid salt, rotating for 30-60 minutes, adding 0.5-1.5% of sodium bicarbonate, rotating for 30-60 minutes, adjusting the pH value of bath liquid to be 4.0-4.8, rotating and stopping for 2-10 hours, and discharging liquid;

the specific steps of the terminal chrome retanning are that 50-300% of water is added into a rotary drum, the temperature in the drum is adjusted to be 30-40 ℃, 0.1-1.5% of cationic fatting agent, 1-5% of chrome tanning agent and 0.5-3% of zirconium-containing polymetallic tanning agent are added, and the rotary drum rotates for 30-90 minutes;

the first neutralization step comprises the steps of adding 50-300% of water into a rotary drum, adjusting the temperature in the drum to 25-40 ℃, adding 1-3% of neutralized tannin and 1-3% of weak organic acid salt, and rotating for 30-90 min;

the second step of neutralization is that 0.5 to 3 percent of sodium bicarbonate is added into the rotary drum, the temperature in the drum is adjusted to be 20 to 45 ℃, and the drum rotates for 30 to 90 minutes; adding 0.5-3% ammonium bicarbonate, rotating for 30-90min, adjusting pH of the bath liquid to 6-7, stopping rotation for 2-10 hr, and discharging liquid;

the first step of fat-liquoring is that 1-3% of aldehyde tanning agent, 1-3% of phospholipid fat-liquoring agent and 1-3% of sulfonate fat-liquoring agent are added into a rotary drum, the temperature in the drum is adjusted to be 25-40 ℃, and the drum rotates for 30-90 minutes;

adding 30-300% of water into the rotary drum, adjusting the temperature in the drum to be 20-45 ℃, adding 1-5% of sulfonate fatting agent, 1-5% of phospholipid fatting agent, 1-5% of synthetic fatting agent and 1-5% of polymer fatting agent, and rotating for 30-120 minutes;

adding 50-300% of hot water into the rotary drum, adjusting the temperature in the drum to 45-55 ℃, adding 1-5% of sulfonate fatting agent, 1-5% of phospholipid fatting agent, 1-5% of synthetic oil and 1-5% of polyacrylic fatting agent, and rotating for 40-90 minutes;

adding 0.1-1.5% of self-emulsified cow's foot oil or raw cow's foot oil into the rotary drum, adjusting the temperature in the drum to be 30-40 ℃, rotating for 10-30 minutes, discharging liquid, washing the liquid, discharging the liquid, and standing after the drum is taken out;

the filling dyeing step I comprises the specific steps of adding 1-8% of amino resin tanning agent, 1-8% of substitute synthetic tanning agent and 1-5% of dye into a rotary drum, adjusting the temperature in the drum to be 20-45 ℃, rotating for 60-180 minutes, adding 50-300% of water, adjusting the temperature in the drum to be 50-60 ℃, rotating for 5-30 minutes, adding 0.5-3.0% of formic acid for 2-4 times, rotating for 20-80 minutes, adjusting the pH value to be 4.0-4.8, and discharging liquid;

in the second filling and dyeing step, 1-5% of amino resin tanning agent, 1-5% of substitute synthetic tanning agent and 1-5% of dye are added into a rotary drum, the temperature in the drum is adjusted to be 20-45 ℃, and the rotary drum rotates for 60-150 minutes; adding 50-300% water, controlling the temperature at 40-60 deg.C, rotating for 5-30 min; adding 0.5-3.0% formic acid 2-3 times, rotating for 20-80 min, adjusting pH to 3-3.8, and discharging liquid.

5. The production process of the thick natural grain-falling high-grade sofa leather according to claim 1, characterized in that the drying and finishing are sequentially as follows: wringing and stretching → stretching of the stretching plate → rewetting → shaking for softening.

6. The production process of the thick natural grain-falling high-grade sofa leather according to claim 1, wherein the coating comprises bottom coating, tumbling, standing, softening, vibrating and softening, toggling and drying, middle coating and top coating; adding graphene-based polysiloxane emulsion into the top coating.

7. The process for producing the thick natural grain-broken high-grade sofa leather according to claim 4, wherein the electrolyte-resistant fatliquor is at least one of sulfonic anionic fatliquor, cationic fatliquor, nonionic fatliquor and amphoteric fatliquor.

8. The production process of the thick natural grain-falling high-grade sofa leather according to claim 6, characterized in that: the rolling finishing temperature is 100-140 ℃, and the pressure is 5-30 kgf; the falling time is 2-30h respectively; the toggling drying temperature is 30-50 deg.C, the time is 10-60min, and the interval is 3-10 cm; standing for 2-12 h.

9. The production process of the thick natural grain-falling high-grade sofa leather according to claim 6, characterized in that: the bottom layer coating and the middle layer coating are the same in coating agent, and the components are 400 parts of water 350-one, 120 parts of comprehensive resin 100-one, 80-100 parts of polyurethane resin, 120 parts of polyacrylic resin 100-one, 40-60 parts of softening agent, 40-60 parts of wax agent, 40-60 parts of filler and 60-80 parts of pigment paste; the top coating finishing agent comprises 150 parts of 100-one water, 120 parts of 100-one polyurethane resin, 3-5 parts of a cross-linking agent and 3-20 parts of graphene-based polysiloxane emulsion.

Technical Field

The invention relates to the technical field of leather-making chemistry and leather-making engineering, in particular to a production process of thick natural pattern-falling high-grade sofa leather.

Background

The thick natural grain-throwing sofa leather is a high-quality decorative furniture leather, and is characterized by uniform, natural and beautiful patterns, mellow, soft, plump, firm and durable, good physical and mechanical properties, good grain-fixing property, good comfort and high utilization rate, so that the sofa leather is pursued once being put into the market, and the prospect is greatly over the expectation.

Because the leather body of thick type natural pattern sofa leather is thicker, consequently have great difference with current slim leather in the course of working, it all with the great difference of normal operating procedure at every process of operation, if leather thickness is great, inside chemical reagent is difficult to permeate the leather, lead to inside leather can not fully absorb chemical reagent, and then influence the leather quality.

Meanwhile, the thick natural grain-broken sofa leather is mainly used for daily sitting and lying and can be scraped with metal articles such as zippers and keys of clothes on a person, so that the improvement of the wear-resisting and scratch-resisting performance of the thick natural grain-broken sofa leather is one of focuses of people, and in addition, whether the thick natural grain-broken sofa leather can prevent water or not is also a focus of people.

Disclosure of Invention

Therefore, aiming at the problems, the invention provides a production process of thick natural pattern-falling high-grade sofa leather, which has the following beneficial effects: according to the characteristics of large thickness, large part difference and slow material permeation of thick wet blue leather and the manufacturing principle of natural textured leather, when a wet dyeing and finishing process is designed, the shaving thickness is controlled to be 3.0-3.5, and the shaving is directly performed without splitting, so that one process can be omitted, the generation amount of wastes such as leather scraps, leather leftover materials and the like can be obviously reduced, the environment-friendly benefit is good, and the utilization value of the wet blue leather is improved.

In order to realize the technical problem, the solution scheme adopted by the invention is as follows: a production process of thick natural pattern-falling high-grade sofa leather comprises the following steps: taking thick blue wet leather, sequentially carrying out wringing, shaving, weighing, softening, front end chromium retanning, neutralization I, fatliquoring I, neutralization II, fatliquoring II, filling dyeing I, fatliquoring III, filling dyeing II, tail end chromium retanning, fatliquoring IV, drying, finishing and finishing;

the softening sequentially comprises surfactant softening, fatting agent softening and enzyme softening;

and adding a zirconium-containing polymetallic tanning agent into both the front-end chromium retanning and the tail-end chromium retanning.

Further, the zirconium-containing multi-metal tanning agent is one or more of a zirconium-aluminum multi-metal complex tanning agent, a chromium-zirconium-aluminum multi-metal complex tanning agent, a zirconium-titanium multi-metal complex tanning agent, a zirconium-aluminum-titanium multi-metal complex tanning agent and an iron-zirconium-aluminum multi-metal complex tanning agent.

Further, the specific steps of softening the surfactant are as follows: taking the weight of the blue wet leather obtained by shaving as a reference, putting the shaved blue wet leather into a rotating drum, adding 50-400% of water, adjusting the temperature in the drum to be 25-45 ℃, adding 0-1.0% of formic acid and 0.1-3.0% of surfactant, rotating for 30-120 minutes, and discharging liquid;

the specific steps of softening the fatting agent are as follows: adding 50-400% of water, adjusting the temperature in the drum to 25-45 ℃, adding 0-1.0% of oxalic acid and 0.1-3% of electrolysis-resistant fat-liquoring agent, rotating for 30-120 minutes, and discharging liquid;

the enzyme softening process includes adding water in 50-400 wt% into the drum, regulating the temperature inside the drum to 20-45 deg.c, regulating the pH value of the bath liquid to 3.0-4.6, adding acid softening enzyme in 0.5-6 wt% and electrolyte resisting fatting agent in 0-2 wt%, rotating for 30-300 min and draining.

Further, the front-end chrome retanning comprises the following specific steps: adding 50-300% of water into a rotary drum, adjusting the temperature in the drum to be 25-40 ℃, adding 0.5-2% of electrolyte-resistant fatting agent and 0.5-2% of fatty aldehyde, rotating for 20-40 minutes, adding 1-5% of chrome tanning agent, 1-5% of chrome-containing tannin and 0.5-3% of zirconium-containing polymetallic tanning agent, rotating for 30-90 minutes, adding 1-3% of weak organic acid salt, rotating for 30-60 minutes, adding 0.5-1.5% of sodium bicarbonate, rotating for 30-60 minutes, adjusting the pH value of bath liquid to be 4.0-4.8, rotating and stopping for 2-10 hours, and discharging liquid;

the specific steps of the terminal chrome retanning are that 50-300% of water is added into a rotary drum, the temperature in the drum is adjusted to be 30-40 ℃, 0.1-1.5% of cationic fatting agent, 1-5% of chrome tanning agent and 0.5-3% of zirconium-containing polymetallic tanning agent are added, and the rotary drum rotates for 30-90 minutes;

the first neutralization step comprises the steps of adding 50-300% of water into a rotary drum, adjusting the temperature in the drum to 25-40 ℃, adding 1-3% of neutralized tannin and 1-3% of weak organic acid salt, and rotating for 30-90 min;

the second step of neutralization is that 0.5 to 3 percent of sodium bicarbonate is added into the rotary drum, the temperature in the drum is adjusted to be 20 to 45 ℃, and the drum rotates for 30 to 90 minutes; adding 0.5-3% ammonium bicarbonate, rotating for 30-90min, adjusting pH of the bath liquid to 6-7, stopping rotation for 2-10 hr, and discharging liquid;

the first step of fat-liquoring is that 1-3% of aldehyde tanning agent, 1-3% of phospholipid fat-liquoring agent and 1-3% of sulfonate fat-liquoring agent are added into a rotary drum, the temperature in the drum is adjusted to be 25-40 ℃, and the drum rotates for 30-90 minutes;

adding 30-300% of water into the rotary drum, adjusting the temperature in the drum to be 20-45 ℃, adding 1-5% of sulfonate fatting agent, 1-5% of phospholipid fatting agent, 1-5% of synthetic fatting agent and 1-5% of polymer fatting agent, and rotating for 30-120 minutes;

adding 50-300% of hot water into the rotary drum, adjusting the temperature in the drum to 45-55 ℃, adding 1-5% of sulfonate fatting agent, 1-5% of phospholipid fatting agent, 1-5% of synthetic oil and 1-5% of polyacrylic fatting agent, and rotating for 40-90 minutes;

adding 0.1-1.5% of self-emulsified cow's foot oil or raw cow's foot oil into the rotary drum, adjusting the temperature in the drum to be 30-40 ℃, rotating for 10-30 minutes, discharging liquid, washing the liquid, discharging the liquid, and standing after the drum is taken out;

the filling dyeing step I comprises the specific steps of adding 1-8% of amino resin tanning agent, 1-8% of substitute synthetic tanning agent and 1-5% of dye into a rotary drum, adjusting the temperature in the drum to be 20-45 ℃, rotating for 60-180 minutes, adding 50-300% of water, adjusting the temperature in the drum to be 50-60 ℃, rotating for 5-30 minutes, adding 0.5-3.0% of formic acid for 2-4 times, rotating for 20-80 minutes, adjusting the pH value to be 4.0-4.8, and discharging liquid;

in the second filling and dyeing step, 1-5% of amino resin tanning agent, 1-5% of substitute synthetic tanning agent and 1-5% of dye are added into a rotary drum, the temperature in the drum is adjusted to be 20-45 ℃, and the rotary drum rotates for 60-150 minutes; adding 50-300% water, controlling the temperature at 40-60 deg.C, rotating for 5-30 min; adding 0.5-3.0% formic acid 2-3 times, rotating for 20-80 min, adjusting pH to 3-3.8, and discharging liquid.

Further, the drying and finishing are as follows in sequence: wringing and stretching → stretching of the stretching plate → rewetting → shaking for softening.

Further, the coating comprises bottom coating, roller finishing, standing, milling, vibration softening, toggling drying, middle coating and top coating; and adding graphene-based polysiloxane emulsion into the top coating.

Furthermore, the electrolyte-resistant fatliquor is at least one of sulfonic anion fatliquor, cation fatliquor, nonionic fatliquor and amphoteric fatliquor.

Further, the roller burnishing temperature is 100-140 ℃, and the pressure is 5-30 kgf; the falling time is 2-30h respectively; the toggling drying temperature is 30-50 deg.C, the time is 10-60min, and the interval is 3-10 cm; standing for 2-12 h.

Further, the bottom layer coating and the middle layer coating are the same in coating agent, and the components are 400 parts of water 350-; the top coating finishing agent comprises 150 parts of 100-one water, 120 parts of 100-one polyurethane resin, 3-5 parts of a cross-linking agent and 3-20 parts of graphene-based polysiloxane emulsion.

By adopting the technical scheme, the invention has the beneficial effects that: compared with the prior art, the production process of the thick natural grain-falling high-grade sofa leather has the following advantages:

1. the existing softening process is generally to add wet blue leather into water containing oxalic acid and degreasing agent, rinse and discharge liquid; the softening process of the invention sequentially adopts surfactant softening, fatting agent softening and enzyme softening, wherein the softening of the surfactant is to wash off dirt on the surface of the leather and to ensure that the leather is refilled with water to expand and wet; softening by the fatting agent not only further moistens the leather by filling water, but also plays a role in softening the leather, and prevents collagen fibers from being broken due to overlarge mechanical action when enzyme is softened in the next step; the enzyme softening is mainly used for completely removing non-collagen components such as fiber stroma, elastin and the like in the leather fiber, so that the chemical materials can enter the thick leather, and three softening processes supplement each other and are not indispensable.

2.2 times of chrome retanning is adopted, and zirconium-containing polymetallic tanning agents are added, so that the chrome retanning agents and the chrome tanning agents can play a synergistic effect to promote the absorption of the tanning agents, the chrome tanning agents are mainly combined with the carboxyl of collagen, but the quantity of the carboxyl of the collagen is limited, when the chrome tanning agents are excessive, a part of chrome and the collagen can only form single-point combination, and a part of chrome and the collagen can not be combined even; the active group binding sites of zirconium and collagen are more than those of chromium, aluminum, iron and titanium, and can react with amino groups and guanidyl groups in the collagen and simultaneously generate coordination and polymerization with chromium, so that the zirconium, the chromium and the collagen can form a multi-element net-shaped cross-linking structure, the absorption of a chromium tanning agent is promoted, the cross-linking degree of a metal tanning agent and the collagen of the leather is improved, and the physical mechanical strength, the wear resistance, the water washing resistance and other properties of the leather are improved.

3. The fatty aldehyde and the fatting agent are added in the front-end chrome retanning procedure, so that the absorption of the metal tanning agent can be promoted, the plumpness of leather can be improved, the charge expansion generated by the cross-linking combination of the aldehyde tanning agent and amino groups on a collagen peptide chain is larger than that generated by the cross-linking combination of the chrome tanning agent and carboxyl groups, meanwhile, the fatty aldehyde can be deposited between fibers in the form of aldehyde polymers, so that the fiber gaps are enlarged, and the leather obtains good looseness and porosity due to the large charge expansion and the polymer deposition, so that the metal tanning agent can quickly and uniformly permeate. Meanwhile, after the aldehyde tanning agent is crosslinked with amino on the collagen, the electrical property of the collagen is out of balance, and the combination of carboxyl on a collagen molecular chain and chromium is facilitated.

4. The binding fastness of an anionic material can be improved by retanning the tail end chromium, the physical and mechanical properties of the leather are improved, the cationic fatliquor and the metal tanning agent are added simultaneously, the binding of the metal tanning agent and the grain surface is slowed down, and the fineness of the grain surface of the leather is ensured; when the pH value is less than pI, the collagen has positive charge, and the larger the difference value between the two is, the stronger the electric property is, and the stronger the absorption binding property on the anion material is. The chrome retanning is carried out at the later stage of fatliquoring, so that the pH value can be reduced, the difference between the pH value and the isoelectric point is increased by moving the isoelectric point to the alkaline direction, the electropositivity is enhanced, and the absorption of an anion material is promoted.

5. The front-end chrome retanning mainly comprises the steps that collagen fibers and collagen fibers are crosslinked together through a metal tanning agent to form a porous material with a multi-element net-shaped crosslinking structure, and the aldehyde tanning agent plays a role in assisting crosslinking; the terminal chrome retanning mainly comprises the step of crosslinking a filler, a dye, a fatliquor and collagen fibers together through a metal tanning agent, so that the binding fastness of the materials is improved, the leather is plump and has a bone feeling, meanwhile, the negative effect of the filler on the mechanical property of the leather is reduced, the physical and mechanical properties of the leather are improved, and the cationic fatliquor mainly plays a role in lubricating the fibers and promoting the penetration.

6. The invention adopts twice neutralization, wherein the neutralizing agent used for the neutralization has good buffering and masking effects, the neutralizing effect is mild, and the neutralizing agent can penetrate into the leather to prevent excessive neutralization; the neutralizing agent sodium bicarbonate used in the neutralization step II has strong neutralizing capacity, the ammonium bicarbonate has mild neutralizing effect, the two neutralizing agents can achieve the purpose of rapid neutralization, and meanwhile, the surface and the interior of the leather have certain difference, so that the subsequent materials are combined in the leather firstly.

7. Because the leather is thick and the chemical materials are not easy to permeate, the greasing agent can permeate into the leather by a method of greasing for a small number of times, so that the leather can achieve the effect of softness and fullness; different fatting agents are adopted according to different isoelectric points of the leather in different procedures and different functions to be realized; the adoption of neutralization and then greasing can not only soften the leather and improve the strength, but also lubricate the fiber and seal the cationic group, so that the filler and the dye can permeate into the skin in the subsequent filling and dyeing process; the fat liquoring after filling and dyeing is main fat liquoring, which mainly plays the roles of softening and plumping the leather and improving the physical and mechanical properties, and also endows the leather with certain hand feeling, such as wax feeling and moist feeling. And the greasing is surface greasing, and is mainly used for endowing the leather with certain hand feeling, such as waxy feeling, smooth feeling and polishing property.

8. The material can fully permeate into the leather by a fractional filling and dyeing method; in the coating process, the proportion of the coating agent resin is high, active groups on side chains among molecular chains can generate cross-linking reaction to form a light three-dimensional net structure, so that the leather coating has good physical properties such as wear resistance, scraping resistance and the like and waterproof performance; the wear-resisting and scratch-resisting performance of the leather can be improved by adding the graphene-based polysiloxane emulsion in the top coating, and the physical and mechanical properties and the sensory properties of the thick natural pattern-falling high-grade sofa leather prepared by adopting the technical scheme completely meet the standard requirements of the sofa leather, so that the thick natural pattern-falling high-grade sofa leather has good practicability.

Detailed Description

The following detailed description will be provided for the embodiments of the present invention with reference to specific embodiments, so that how to apply the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented. Unless otherwise indicated, the techniques employed in the examples are conventional and well known to those skilled in the art, and the reagents and products employed are also commercially available.

Some specific examples of the present invention are provided below to aid in further understanding of the present invention, but the scope of the present invention is not limited to these examples.

A production process of thick natural pattern-falling high-grade sofa leather comprises the following process steps:

taking thick blue wet leather, squeezing water, shaving evenly (thickness: 3.2mm), weighing;

softening the surfactant: the reagent dosage is calculated by the weight percentage of the blue wet leather obtained by shaving, the shaved blue wet leather is put into a rotating drum, 280 percent of water is added, the temperature in the drum is adjusted to be 42 ℃, 0.4 percent of formic acid and 0.3 percent of surfactant SAF (Delui leather chemical company) are added, and the rotating is carried out for 50 minutes; draining;

softening the fatting agent: adding 200% of water into a rotary drum, adjusting the temperature in the drum to 38 ℃, adding 0.6% of oxalic acid and 1.0% of nonionic fatliquoring agent TRUPON OSL (Toeplier leather chemical Co., Ltd.), rotating for 60 minutes, and discharging liquid;

enzyme softening: adding 200% of water into a rotary drum, adjusting the temperature in the drum to be 43 ℃, adjusting the pH value of bath liquid to be 4.3-4.4, adding 4.5% of acidic protease NOWOLASE WA (Yixiang chemical company) and 1.5% of sulfited fish oil EUREKA400-R (Attapus chemical company), rotating for 240 minutes, and discharging liquid;

front-end chrome retanning: adding 100% of water into a rotary drum, adjusting the temperature in the drum to 33 ℃, adding 1% of electrolyte-resistant fatting agent TRUPON PEM (Toeplier leather chemical company) and 1.2% of fatty aldehyde NOVALTAN PF (Sema leather chemical company), and rotating for 30 minutes; adding 3% chrome tanning agent KROMSAN AB (Jinshan trade Co., Ltd.), 2% chrome-containing tannin BITAN BO (UniteK chemical Co., Ltd.), and 2% zirconium aluminum titanium complex tanning agent (Jinkun chemical Co., Ltd., Mianzhu city), and rotating for 60 min; adding 2% sodium formate, and rotating for 300 minutes; adding 0.6-0.8% sodium bicarbonate, rotating for 50min, and adjusting bath liquid pH to 4.3-4.4; stopping the rotation for 210 minutes in a mode of rotating for 3 minutes and stopping for 33 minutes, and discharging the liquid;

neutralization one: adding 150% water into the rotary drum, adjusting the temperature in the drum to 35 deg.C, adding 2.5% neutralized tannin TANIGAN PAK-S (Langshen leather chemical company) and 2% sodium formate, and rotating for 40 min;

fat liquoring I: adding 2% aldehyde tanning agent TRUPOTAN OXB (Toeplier leather chemical company), 2% phospholipid fatting agent PROVOL BA (Sima leather chemical company) and 2% sulfonate fatting agent LUTAPOLRUN (Shandong Riboku chemical company) into the rotary drum, keeping the temperature in the drum at 35 ℃, and rotating for 50 minutes;

and (2) neutralization: adding 1.2% sodium bicarbonate into the rotary drum, and rotating for 40 minutes; adding 1.5% ammonium bicarbonate, maintaining the temperature in the drum at 35 deg.C, rotating for 50min, and adjusting the pH value of the bath liquid to 6.6-6.7; rotating for 5 minutes and stopping for 35 minutes, and stopping for 480 minutes; draining;

and (2) fat adding: adding 60% of water into a rotary drum, adjusting the temperature in the drum to 31 ℃, adding 2.5% of sulfonate fatliquor VILIONFABUP (Convergence leather chemical company), 2.5% of phospholipid fatliquor TRUPON DB (Toepler leather chemical company), 3% of synthetic oil PELLASTOL 94S (Sema leather chemical company) and 3% of polyacrylic fatliquor SFT-F (Deli leather chemical company), and rotating for 60 minutes;

filling and dyeing: adding 3% amino resin tanning agent TRUPOTAN HB (Toepler leather chemical company), 3% substitute synthetic tanning agent RETINGAN BN (Langshan chemical company, Ltd.), 3% dye into the rotary drum, keeping the temperature in the drum at 31 ℃, and rotating for 120 minutes; adding 120% hot water, rotating for 20 minutes, and adjusting the temperature in the drum to 52 ℃; adding 1.5% formic acid in 2 times, rotating for 40min, and adjusting pH to 4.4-4.5; draining;

and (3) fat adding: adding 100% hot water into the rotary drum, adjusting the temperature in the drum to 45 ℃, adding 3% of sulfonate fatting agent LUTAPOL RUN, 3% of phospholipid fatting agent TRUPON DB, 3% of synthetic oil PELLASTOL 94S and 2% of polyacrylic fatting agent MAGNOPLAL SFT-F (Delui leather chemical company), and rotating for 60 minutes;

filling and dyeing II: adding 1.5% amino resin tanning agent TRUPOTAN HB, 1.5% substitute synthetic tanning agent BASYNTAN FR-BC (BASF leather chemical Co., Ltd.), 1.5% dye into the rotary drum, keeping the temperature in the drum at 45 deg.C, and rotating for 40 min; adding 100% warm water, rotating for 20 minutes, and adjusting the temperature in the drum to 52 ℃; adding 2.2% formic acid for 3 times, rotating for 50min, adjusting pH to 3.4-3.5, draining, washing with water, and draining;

terminal chrome retanning: adding 200% of water into the rotary drum, adjusting the temperature in the drum to 35 ℃, adding 1% of cationic fatting agent CATALIX GS (Stelar chemical company), 2% of chrome tanning agent KROMSAN AB and 1% of zirconium-aluminum-titanium complex tanning agent (Jinkun chemical company, Mianzhu city), and rotating for 40 minutes;

and C, fat adding: adding 0.8% of self-emulsified neat's foot oil BITOIL OPE (UniteK chemical company) into the rotary drum, keeping the temperature in the drum at 35 ℃, rotating for 10-30 minutes, discharging liquid, washing with water, discharging liquid, and standing after the drum is taken out;

example of coating application:

(1) the components of the bottom layer coating agent and the middle layer coating agent are the same, and are 400 parts of water; 120 parts of comprehensive resin RC-78-555 (Steyr chemical Co.); 100 parts of polyurethane resin RU-3904 (Stahl chemical Co.); 120 parts of polyacrylic resin RA-2312 (Steyr chemical Co.); 40 parts of a softening agent Euderm Nappa Soft S-C (Lansheng chemical Co., Ltd.); wax 48416-GAA (Pickle chemical Co., Ltd.) 40 parts; 40 parts of FILLER BIOFIN FILLER FD (Bai Euro chemical company); 60 parts of pigment paste PPE DEEP BLACK A-ID (Steyr chemical Co.).

(2) The top coating finishing agent comprises 120 parts of water; 100 parts of polyurethane resin AQUALEN TOP LN.A (St. Tael chemical Co., Ltd.); 5 parts of cross-linking agent AQUALEN AKU (St. Taer chemical Co., Ltd.) and 8 parts of graphene-based polysiloxane emulsion (prepared by the method described in the patent "preparation method and application method of high-physical-property graphene-based leather finishing agent" (application No. 201811383945.0)).

(3) The operation process comprises the following steps: bottom coating → tumbling (120 ℃/20kgf) → standing (4h) → tumbling (30h) → vibration staking (level 2) → toggling dry (40 ℃/20min/4cm) → middle coating → tumbling (110 ℃/10kgf) → top coating → tumbling (120 ℃/20kgf) → standing (4h) → tumbling (2h) → vibration staking (level 2) → tumbling (100 ℃/5kgf) → finished product.

The above description is only an embodiment utilizing the technical content of the present disclosure, and any modification and variation made by those skilled in the art can be covered by the claims of the present disclosure, and not limited to the embodiments disclosed.