A high-performance raw cowhide leather production process based on salt-free pickling and high-pH value chrome tanning

Abstract

The application discloses a high-performance cattle crust production process based on salt-free pickling and high-pH value chrome tanning, and is characterized in that the process comprises the following steps in sequence: water washing of yellow cattle softened pelt, salt-free pickling, chrome tanning, alkali extraction, water washing out of drum, standing, water squeezing, shaving, weighing, softening rinsing, water washing, chrome-zirconium combined retanning, neutralization, water washing, filling, fatting, surface treatment, water washing out of drum, standing and drying finishing; aromatic sulfonic acid or aromatic sulfonic acid oligomer is selected as a pickling agent in the salt-free pickling process; at least chlorosulfonated paraffin fatting agent, modified glutaraldehyde, chrome tanning agent, zirconium tanning agent, amphoteric aromatic sulfonic acid condensate and natural protein filler are added in the chrome-zirconium combined retanning process; the production process disclosed by the application can effectively solve the problems of chloride ion and chrome pollution caused by traditional pickling-chrome tanning technology, and simultaneously provides a wet-state dyeing and finishing process technology for transforming blue wet leather into crust leather without reducing the physical and mechanical strength of the blue wet leather.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tanning technology, and particularly relates to a high-performance raw cowhide production process based on salt-free pickling and high-pH value chrome tanning. BACKGROUND

[0002] Chrome tanned leather has excellent properties such as moisture and heat stability, resilience, fullness, and physical and mechanical strength, so that chrome tanning is still the most widely used tanning method in the current and future tanning industry. Pickling is a very important process in the chrome tanning process, and its purpose is to adjust the pH value of the raw hide, further loosen the collagen fibers, and provide protection for the penetration of the chrome tanning agent into the collagen fiber matrix. However, in the traditional pickling-chrome tanning process, in order to inhibit the acid swelling of the raw hide, 6-8% of neutral salt (NaCl) by weight of the raw hide is added, and the absorption rate of chromium is only 65-75%, resulting in the concentration of chloride ions and total chromium in the tanning waste liquid reaching more than 20,000 mg / L and 2,000 mg / L, respectively. The relevant laws of the state have made clear provisions for the emission concentration of chloride ions and chromium in tanning wastewater, and the total chloride ion content should not exceed 3,000 mg / L, and the total chromium content should not exceed 1.5 mg / L. Therefore, it is particularly urgent to solve the pollution problems of chloride ions and chromium caused by the traditional pickling-chrome tanning technology. SUMMARY

[0003] The present application provides a high-performance raw cowhide production process based on salt-free pickling and high-pH value chrome tanning, which solves the technical problem of excessive concentration of chloride ions and total chromium in the tanning waste liquid in the prior art, realizes source control, does not use neutral salt in the pickling process, improves the absorption rate of chromium in the chrome tanning process, greatly reduces the concentration of chloride ions and chromium in the tanning waste liquid, and relieves the pressure of end-of-pipe treatment of tanning wastewater.

[0004] The present application provides a high-performance raw cowhide production process based on salt-free pickling and high-pH value chrome tanning, which sequentially comprises the following processes: water washing of yellow soft raw hide, salt-free pickling, chrome tanning, alkali extraction, water washing out of drum, standing, water squeezing, shaving, weighing, softening and rinsing, water washing, chrome-zirconium combined retanning, neutralization, water washing, padding, fatliquoring, surface treatment, water washing out of drum, standing, and drying finishing.

[0005] In the salt-free pickling process, an aromatic sulfonic acid or an aromatic sulfonic acid oligomer is selected as a pickling agent;

[0006] In the chrome-zirconium combined retanning process, at least chlorosulfonated paraffin fatliquoring agent, modified glutaraldehyde, chrome tanning agent, zirconium tanning agent, amphoteric aromatic sulfonic acid condensate, and natural protein padding are added.

[0007] The filling process at least adds a ternary copolymer aqueous solution, an acrylic polymer retanning agent, an amino resin tanning agent, a vegetable tanning agent, a synthetic tanning agent, a sulfonic acid-based synthetic fatliquoring agent, and a phosphate ester-based synthetic fatliquoring agent.

[0008] The fatliquoring process at least adds natural protein fillers, synthetic soft oil, chlorosulfonated paraffin fatliquoring agent, sulfuric acid-based synthetic fatliquoring agent, phosphate ester-based synthetic fatliquoring agent, sulfited lanolin, and self-emulsifying natural cow hoof oil.

[0009] Further, the amino resin tanning agent in the filling process is selected from one or more of dicyandiamide resin tanning agent, melamine resin tanning agent, and amphoteric melamine resin tanning agent.

[0010] The vegetable tanning agent in the filling process is selected from one or more of modified quebracho and white quebracho.

[0011] The synthetic tanning agent in the filling process is selected from one or more of phenolic synthetic tanning agent, sulfone synthetic tanning agent, and phenol-sulfone copolymer synthetic tanning agent.

[0012] Further, the specific steps of the salt-free pickling process are as follows: 30-50% water and 1.0-1.5% pickling agent are added to the rotating drum at a temperature of 18-23°C, and then 1.0-1.5% pickling agent is added and the drum is rotated, and the bath pH is 4.0-4.5.

[0013] The chrome tanning process is carried out in the same bath as the salt-free pickling process, and the specific steps are as follows: 2.5-3.0% chrome tanning agent and 0.2-0.5% acid-resistant and electrolyte-resistant fatliquoring agent are added to the bath, and then 2.5-3.0% chrome tanning agent is added and the bath is rotated, and the bath pH is 2.9-3.4.

[0014] The alkali extraction process is carried out in the same bath as the salt-free pickling process and the chrome tanning process, and the specific steps are as follows: 0.3-0.5% automatic alkali extraction agent is added to the bath in two portions, and then 150-200% water and 0.15-0.3% mildew-resistant agent are added, and the bath is rotated at a temperature of 38-40°C.

[0015] Further, the specific steps of the softening and rinsing process are as follows: 200-300% water, 0.5-1.5% sulfonate humectant, 1.0-2.0% acid protease, 0.2-0.5% sulfated fatty alcohol degreasing agent, and 1.0-1.5% oxalic acid are added to the rotating drum at a temperature of 40-45°C, and then the drum is rotated.

[0016] Further, the specific steps of the chrome-zirconium combined retanning process are as follows: adding 100-150% water, 1.0-2.5% chlorosulfonated paraffin fat-liquoring agent, 1.5-3.0% modified glutaraldehyde into the rotating drum, rotating at 30-32℃; adding 0.3-0.5% formic acid in two portions, rotating, adjusting the bath pH to 2.6-2.9; adding 1.0-3.0% chrome tanning agent, 0.5-1.5% zirconium tanning agent, 1.0-3.0% amphoteric aryl sulfonic acid condensate, 2.5-4.0% natural protein filler, rotating; adding 1.0-1.5% sodium formate, rotating; adding 0.5-1.0% baking soda in two portions, rotating, adjusting the bath pH to 3.8-4.1.

[0017] Further, the specific steps of the neutralization process are as follows: adding 100-150% water, 1.0-3.0% neutralization tannin, 1.0-1.5% sodium formate into the rotating drum, rotating at 30-32℃; adding 1.0-1.5% baking soda, 0.5-0.8% sodium bisulfite, rotating, adjusting the bath pH to 4.6-4.9; adding 1.5-3.0% fatty alcohol sulfate derivative, rotating.

[0018] Further, the specific steps of the filling process are as follows: adding 30-80% water, 2.0-5.0% low-molecular-weight acrylic polymer retanning agent, 2.0-8.0% medium-molecular-weight acrylic polymer retanning agent, 2.0-6.0% high-molecular-weight acrylic polymer retanning agent into the rotating drum, rotating at 30-32℃; adding 4.0-8.0% terpolymer aqueous solution, 2.0-8.0% dicyandiamide resin tanning agent, 3.0-6.0% melamine resin tanning agent, 3.0-6.0% amphoteric melamine resin tanning agent, 2.0-5.0% white sumac resin, 1.0-4.0% phenolic synthetic tanning agent, 2.0-5.0% sulfone synthetic tanning agent, rotating; adding 1.0-4.0% sulfonic acid-based synthetic fat-liquoring agent, 1.0-4.0% phosphate ester-based synthetic fat-liquoring agent, rotating; adding 5.0-8.0% modified quebracho, 2.0-6.0% phenol-sulfone copolymer synthetic tanning agent, rotating;

[0019] The fat-liquoring process is carried out in the same bath as the filling process, and the specific steps are as follows: adding 150-200% hot water, 2.0-5.0% natural protein filler, 2.0-5.0% synthetic soft oil, 2.0-4.0% chlorosulfonated paraffin fat-liquoring agent, 1.5-4.0% phosphate ester-based synthetic fat-liquoring agent, 1.5-3.0% sulfuric acid-based synthetic fat-liquoring agent, 1.5-3.0% sulfited lanolin, 1.5-4.0% self-emulsifying natural ox hoof oil, 0.1-0.3% mildew inhibitor into the bath, rotating at 50-53℃; adding 2.0-3.5% formic acid in two portions, rotating, adjusting the bath pH to 3.2-3.6.

[0020] Further, the specific steps of the surface treatment process are: adding 200-300% hot water, 0.5-1.0% self-emulsifying natural oxhide oil, and 0.5-1.5% cationic fatliquoring agent into the rotating drum, and rotating at a temperature of 50-53°C.

[0021] Further, the drying finishing process comprises, in sequence, water squeezing and stretching, vacuum drying, air drying, moisture regaining, standing, and oscillation softening.

[0022] The one or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0023] 1. In the traditional pickling process, 6-8% neutral salt is usually used to adjust the pickling liquid Baume degree to 6.5-8.0°Be, so as to achieve Tangnan balance, osmotic pressure balance, reduce the water absorption of raw hide, prevent acid swelling of raw hide, and achieve the purpose of pickling. Generally, the pH value at the end of the traditional pickling process is controlled at 2.4-2.8. Low pH value will cause partial degradation of collagen fibers, thereby negatively affecting the physical and mechanical strength of blue wet leather, and easily causing loose surface phenomenon. In the salt-free pickling process, aromatic sulfonic acid or aromatic sulfonic acid oligomer is selected. Aromatic sulfonic acid or aromatic sulfonic acid oligomer belongs to non-swelling acid, and can completely replace formic acid and sulfuric acid in the traditional pickling process, thereby reducing the pH value of the pickling liquid, and the sulfonic acid group on the benzene ring in the structure can form stable ionic bond (-SO3 - -- + NH3-) with the amino group on the side chain of collagen fibers, partially blocking the positive charge on the side chain of collagen fibers under acidic conditions, reducing the hydrophilicity of collagen fibers, and achieving the effect of inhibiting acid swelling of raw hide without using neutral salt, thereby achieving the purpose of salt-free pickling.

[0024] 2、Traditional chrome tanning process, the pH value is low in the early stage of tanning, the chrome tanning agent is mainly penetrated, and the pH value is adjusted to 3.9-4.3 through alkali extraction in the later stage of tanning, so that the chrome tanning agent is combined with collagen fibers, and the absorption rate of the chrome tanning agent is low. The chrome tanning process and the salt-free pickling process of the application are carried out in the same bath, the sulfonic acid group in the aromatic sulfonic acid or its oligomer structure can form a certain masking effect on Cr(III), which is conducive to the penetration of the chrome tanning agent. Because the pH value at the end of the salt-free pickling process is 4.0-4.5, the high pH value is more suitable for the combination of the chrome tanning agent and collagen fibers, when the chrome tanning agent penetrates into the leather, Cr(III) forms coordination combination with the carboxyl group on the side chain of collagen fibers to produce tanning effect. With the progress of tanning reaction, H+ is gradually released, so that the pH value gradually decreases to 2.9-3.4, and the low pH is more suitable for the penetration of the chrome tanning agent, so the chrome tanning agent will further penetrate into the leather, and through the later alkali extraction process, the pH value is adjusted to 3.9-4.3, so that Cr(III) further forms coordination combination with the carboxyl group on the side chain of collagen fibers, thereby effectively improving the chrome tanning effect, improving the absorption rate of chromium and the uniformity of chromium distribution in the blue wet leather.

[0025] 3、Because the internal chromium content of the blue wet leather formed by the salt-free pickling-high pH value chrome tanning technology is high and uniformly distributed, if the traditional chrome retanning technology is used, the absorption rate of chromium is low, resulting in high chromium content in the retanning waste liquid. The application adopts chrome-zirconium combined retanning, and zirconium tanning agent cooperates with chrome tanning agent for retanning, which on the one hand reduces the dosage of chrome tanning agent, and on the other hand, compared with the chain-like structure of chromium complex, the zirconium complex is a bulky structure with tetramer as the smallest structural unit, has a large spatial structure, has good tanning and filling effects, can strengthen the cross-linking degree of collagen fibers, improve the physical and mechanical strength of the crust leather, and can provide binding points for subsequent materials.

[0026] 4、The ternary copolymer used in the filling process of the application is a modified product containing dicyandiamide resin and melamine resin. The amino resin itself contains rich active groups such as N-methylol group, imine group and urea group, and the activity of the groups in the modified product is further improved, thereby showing strong cross-linking property, so as to strengthen the cross-linking degree of the retanning agent with the retanning agent, the retanning agent with collagen fibers, and improve the physical and mechanical strength, tightness, fullness, resilience and other sensory properties of the crust leather.

[0027] 5、The chlorosulfonated paraffin fatliquoring agent used in the fatliquoring process of the application is a chlorosulfonated modified product of paraffin wax. Paraffin wax is a hydrocarbon compound, which has excellent light resistance and weather resistance. After chlorosulfonated modification, active group -SO2Cl is introduced, which shows high affinity, thereby improving the cross-linking degree of the fatliquoring agent with the fatliquoring agent, the fatliquoring agent with collagen fibers, and improving the physical and mechanical strength and softness and other sensory properties of the crust leather. DETAILED DESCRIPTION

[0028] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with the description and specific embodiments (the raw material usage in the examples has two bases, among which the chemical material usage in the salt-free pickling, chrome tanning and alkali extraction processes is based on the weight of the gray hide, for example, if the gray hide is 100 kg, 30% water is 30 kg of water; the chemical material usage in the softening rinsing, retanning, neutralization, filling, fat-liquoring and surface treatment processes is based on the weight of the blue wet leather after shaving, for example, if the blue wet leather is 100 kg, 30% water is 30 kg of water).

[0029] A high-performance raw cowhide production process based on salt-free pickling and high-pH value chrome tanning, comprising the following process steps:

[0030] Water washing of yellow cow softening hide → salt-free pickling → chrome tanning → alkali extraction → water washing out of drum (to obtain blue wet leather) → standing → water squeezing → shaving → weighing → softening rinsing → water washing → chrome-zirconium combined retanning → neutralization → water washing → filling → fat-liquoring → surface treatment → water washing out of drum → standing → water squeezing and stretching → vacuum drying → hanging drying → re-humidification → standing → vibration and softening (to obtain raw leather).

[0031] (1) Conventional water washing;

[0032] (2) Salt-free pickling: 30% water, 1.0% pickling agent Corotan MCS (BASF Chemical Co., Ltd.) is added to the drum, the temperature is 20°C, and rotation is performed for 60 min; 1.5% pickling agent Corotan MCS (BASF Chemical Co., Ltd.) is additionally added, rotation is performed for 60 min, and the bath pH is 4.1;

[0033] (3) Chrome tanning: the chrome tanning process is performed in the same bath as the salt-free pickling process, 3.0% chrome tanning agent Chromosal B (Brother Science and Technology Co., Ltd.) and 0.3% acid-resistant and electrolyte-resistant fat-liquoring agent TRUPON PEM (Tomple Co., Ltd.) are added to the bath, and rotation is performed for 60 min; 3.0% chrome tanning agent Chromosal B (Brother Science and Technology Co., Ltd.) is additionally added, rotation is performed for 150 min, and the bath pH is 3.2;

[0034] (4) Alkali extraction: the alkali extraction process is performed in the same bath as the salt-free pickling process and the chrome tanning process, 0.35% automatic alkali extraction agent MgO (Bosika Chemical Co., Ltd.) is added to the bath in two times, each time rotation is performed for 60 min, the bath pH is adjusted to 4.2; 200% water and 0.2% mildew-proof agent BUSAN 1336 (Bakman Chemical Co., Ltd.) are additionally added, the temperature is 40°C, and rotation is performed for 360 min;

[0035] (5) Conventional water washing;

[0036] (6) Standing, water squeezing, shaving and weighing;

[0037] (7) Softening back rinsing: add 300% water, 0.8% sulfonate wetting agent SYNCUROL FP (Sima Chemical Co.), 2.0% acid protease DESOBATE TN (Desiral Chemical Industry Co.), 0.3% sulfated fatty alcohol degreasing agent BORRON SAF (Dreves Leather Technology Co.), 1.0% oxalic acid (Long Xiang Industry Co.) into the drum, temperature 42℃, rotation 180min;

[0038] (8) Normal water washing;

[0039] (9) Chrome-zirconium combined retanning: add 100% water, 2.0% chlorosulfonated paraffin fatliquoring agent INGRASSANTE TSP (ALPA Chemical Co., Italy), 2.0% modified glutaraldehyde SYNEKTAN GTA (Star Chemical Co.) into the drum, temperature 30℃, rotation 30min; add 0.3% formic acid in 2 times, each time rotation 20min, adjust bath pH to 2.7; add 2.0% chrome tanning agent Chromosal B (Brother Science and Technology Co.), 1.0% zirconium tanning agent TJ-T602 (Sichuan Tingjiang New Material Co.), 2.5% amphoteric aryl sulfonic acid condensate Basyntan AN (BASF Chemical Co.), 2.5% natural protein filler DESOATEN FB (Desiral Chemical Industry Co.), rotation 120min; add 1.0% sodium formate, rotation 30min; add 0.5% baking soda in 2 times, each time rotation 45min, adjust bath pH to 3.9;

[0040] (10) Neutralization: add 150% water, 2.0% neutralization tannin TANIGAN PAK-S (Longsheng Chemical Co.), 1.0% sodium formate into the drum, temperature 30℃, rotation 30min; add 1.0% baking soda, 0.6% sodium bisulfite, rotation 40min, adjust bath pH to 4.8; add 2.5% fatty alcohol sulfate derivative PERAMIT LSW (Cognis Chemical Co., Germany), rotation 60min;

[0041] (11) Normal water washing;

[0042] (12) padding: add 50% water, 3.0% small molecular weight acrylic polymer retanning agent TRUPOTAN R83 (Tupler), 5.0% medium molecular weight acrylic polymer retanning agent INTAN TP 340 (ALPA, Italy), 3.0% large molecular weight acrylic polymer retanning agent BAYTIGAN AR (Langsun), temperature 30℃, rotation 60min; add 5.0% ternary copolymer aqueous solution Relugan AG (BASF), 4.0% dicyandiamide resin tanning agent RENEKTAN DCT (Star), 4.0% melamine resin tanning agent TRUPOTAN HB (Tupler), 3.0% amphoteric melamine resin tanning agent TRUPOTAN MAU (Tupler), 4.0% white extract BIOTAN S88 (Baiou), 2.0% phenolic synthetic tanning agent Tamol M (BASF), 3.0% sulfone synthetic tanning agent TANIGAN OS (Langsun), rotation 60min; add 1.5% sulfonic acid-based synthetic fatliquoring agent INGRASSANTE VA3 (ALPA, Italy), 1.5% phosphate-based synthetic fatliquoring agent DERNINOL NLM (Star), rotation 30min; add 6.0% modified extract UNITAN ATO (Younite), 3.0% phenol-sulfone copolymer synthetic tanning agent SELLATAN RL (Derui), rotation 90min;

[0043] (13) fatliquoring: fatliquoring process is carried out in the same bath as padding process, add 150% hot water, 3.0% natural protein filler DESOATEN FB (Desai), 3.0% synthetic soft oil PELLASTOL 94S (Simag), 4.0% INGRASSANTE TSP (ALPA, Italy), 2.0% phosphate-based synthetic fatliquoring agent DERNINOL NLM (Star), 2.0% sulfuric acid-based synthetic fatliquoring agent TRUPON DB (Tupler), 2.0% sulfited lanolin PATEK ZLN (Biso, Italy), 2.0% self-emulsifying natural ox hoof oil BITOIL OPE (Taiji), 0.2% mildewproofing agent BUSAN 1336 (Bakman), temperature 53℃, rotation 90min; add 3.0% formic acid in 2 times, each time rotation 20min, adjust bath pH to 3.4;

[0044] (14) Surface treatment: add 300% hot water, 0.8% self-emulsified natural oxhide oil BITOIL OPE (Tiger Industrial Co., Ltd.), 1.2% cationic fatliquor CATALIX GS-HKI (Star Company) into the drum, temperature 53°C, rotate for 30 min;

[0045] (15) Regular water washing;

[0046] (16) Stand, squeeze and stretch, vacuum drying, air drying, re-moistening, stand, oscillation softening.

[0047] Experimental detection

[0048] According to the process in the examples, the chloride ion content, total chromium content in the tanning waste liquid and the physical and mechanical properties of the blue wet leather and crust leather are detected respectively, wherein the chloride ion content and total chromium content are detected from the waste liquid after the alkali extraction process, and the results are shown in Table 1.

[0049] Table 1: Detection results of chloride ion content, total chromium content in tanning waste liquid and physical and mechanical properties of blue wet leather and crust leather

[0050]

[0051] The above-described is only an embodiment using the technical content of the present application, and any modification or change made by those skilled in the art using the present application is within the scope of the patent claimed by the present application, and is not limited to the embodiments disclosed.

Claims

1. A high performance raw cow leather production process based on salt free pickling, high pH value chrome tanning characterized in that, The process comprises the following steps in sequence: water washing of softened rawhide of yellow cattle, salt-free pickling, chrome tanning, alkali extraction, water washing out of drum, standing, water squeezing, shaving, weighing, softening and rinsing, water washing, chrome-zirconium combined retanning, neutralization, water washing, padding, fatting, surface treatment, water washing out of drum, standing, drying and finishing; The aromatic sulfonic acid or aromatic sulfonic acid oligomer is selected as the pickling agent in the salt-free pickling process; The chrome-zirconium combined retanning process at least adds chlorosulfonated paraffin fatting agent, modified glutaraldehyde, chrome tanning agent, zirconium tanning agent, amphoteric aromatic sulfonic acid condensate and natural protein padding agent; The padding process at least adds terpolymer aqueous solution, acrylic polymer retanning agent, amino resin tanning agent, vegetable tanning agent, synthetic tanning agent, sulfonic acid-based synthetic fatting agent and phosphate ester-based synthetic fatting agent, and the terpolymer aqueous solution is Relugan AG of BASF Chemical Company; The fatting process at least adds natural protein padding agent, synthetic soft oil, chlorosulfonated paraffin fatting agent, sulfuric acid-based synthetic fatting agent, phosphate ester-based synthetic fatting agent, sulfited lanolin and self-emulsifying natural cattle hoof oil. The specific steps of the salt-free pickling process are as follows: 30-50% water and 1.0-1.5% pickling agent are added into a rotating drum at a temperature of 18-23℃; 1.0-1.5% pickling agent is supplemented and the drum is rotated; and the bath pH is 4.0-4.

5. The chrome tanning process is carried out in the same bath as the salt-free pickling process, and the specific steps are as follows: 2.5-3.0% chrome tanning agent and 0.2-0.5% acid-resistant electrolyte fatting agent are added into the bath, and the drum is rotated; 2.5-3.0% chrome tanning agent is supplemented, the drum is rotated, and the bath pH is 2.9-3.

4. The alkali extraction process is carried out in the same bath as the salt-free pickling process and the chrome tanning process, and the specific steps are as follows: 0.3-0.5% automatic alkali extraction agent is added into the bath in two times, the drum is rotated, the bath pH is adjusted to 3.9-4.3, and 150-200% water and 0.15-0.3% mildew-proof agent are supplemented at a temperature of 38-40℃, and the drum is rotated.

2. The high-performance raw cowhide production process based on salt-free pickling and high-pH value chrome tanning according to claim 1, characterized in that, The amino resin tanning agent in the padding process is selected from one or more of dicyandiamide resin tanning agent, melamine resin tanning agent and amphoteric melamine resin tanning agent, the melamine resin tanning agent is TRUPOTAN HB of Tompul Company, and the amphoteric melamine resin tanning agent is TRUPOTAN MAU of Tompul Company; The vegetable tanning agent in the padding process is selected from one or more of modified quebracho and white quebracho; The synthetic tanning agent in the padding process is selected from one or more of phenolic synthetic tanning agent, sulfone synthetic tanning agent and phenol-sulfone copolymer synthetic tanning agent.

3. A process for the production of high performance bovine crust leather based on salt-free pickling and high pH value chrome tanning as claimed in claim 1, wherein, The specific steps of the softening and rinsing process are as follows: 200-300% water, 0.5-1.5% sulfonate humectant, 1.0-2.0% acid protease, 0.2-0.5% sulfated fatty alcohol degreasing agent and 1.0-1.5% oxalic acid are added into a rotating drum at a temperature of 40-45℃.

4. A process for production of high performance cow upper leather based on salt free pickling, high pH value chrome tanning as claimed in claim 1, wherein, The specific steps of the chrome-zirconium combined retanning process are: adding 100-150% water, 1.0-2.5% chlorosulfonated paraffin fatting agent, 1.5-3.0% modified glutaraldehyde into the drum, rotating at a temperature of 30-32℃; adding 0.3-0.5% formic acid in two portions, rotating, adjusting the bath pH to 2.6-2.9; adding 1.0-3.0% chrome tanning agent, 0.5-1.5% zirconium tanning agent, 1.0-3.0% amphoteric aryl sulfonic acid condensate, 2.5-4.0% natural protein filler, rotating; adding 1.0-1.5% sodium formate, rotating; adding 0.5-1.0% baking soda in two portions, rotating, adjusting the bath pH to 3.8-4.

1.

5. A process for the production of high performance bovine crust leather based on salt-free pickling and high pH value chrome tanning as claimed in claim 1, wherein, The specific steps of the neutralization process are: adding 100-150% water, 1.0-3.0% neutralizing tannin, 1.0-1.5% sodium formate into the drum, rotating at a temperature of 30-32℃; adding 1.0-1.5% baking soda, 0.5-0.8% sodium bisulfite, rotating, adjusting the bath pH to 4.6-4.9; adding 1.5-3.0% fatty alcohol sulfate ester derivative, rotating.

6. The high-performance cowhide leather production process based on salt-free pickling and high-pH chrome tanning according to claim 1, characterized in that, The specific steps of the filling process are: adding 30-80% water, 2.0-5.0% small molecular weight acrylic polymer retanning agent, 2.0-8.0% medium molecular weight acrylic polymer retanning agent, 2.0-6.0% large molecular weight acrylic polymer retanning agent into the drum, rotating at a temperature of 30-32℃; adding 4.0-8.0% terpolymer aqueous solution, 2.0-8.0% dicyandiamide resin tanning agent, 3.0-6.0% melamine resin tanning agent, 3.0-6.0% amphoteric melamine resin tanning agent, 2.0-5.0% white sumac resin, 1.0-4.0% phenolic synthetic tanning agent, 2.0-5.0% sulfone synthetic tanning agent, rotating; the melamine resin tanning agent is TRUPOTAN HB from Tompul Company, and the amphoteric melamine resin tanning agent is TRUPOTAN MAU from Tompul Company; adding 1.0-4.0% sulfonic acid-based synthetic fatting agent, 1.0-4.0% phosphate ester-based synthetic fatting agent, rotating; adding 5.0-8.0% modified quebracho, 2.0-6.0% phenol-sulfone copolymer synthetic tanning agent, rotating; The fatting process is carried out in the same bath as the filling process, and the specific steps are: adding 150-200% hot water, 2.0-5.0% natural protein filler, 2.0-5.0% synthetic soft oil, 2.0-4.0% chlorosulfonated paraffin fatting agent, 1.5-4.0% phosphate ester-based synthetic fatting agent, 1.5-3.0% sulfuric acid-based synthetic fatting agent, 1.5-3.0% sulfited lanolin, 1.5-4.0% self-emulsifying natural cattle hoof oil, 0.1-0.3% mildew inhibitor into the bath, rotating at a temperature of 50-53℃; adding 2.0-3.5% formic acid in two portions, rotating, adjusting the bath pH to 3.2-3.

6.

7. A process for the production of high performance bovine crust leather based on salt-free pickling and high pH value chrome tanning as claimed in claim 1, wherein, The specific steps of the surface treatment process are: adding 200-300% hot water, 0.5-1.0% self-emulsified natural oxhide oil and 0.5-1.5% cationic fatliquor into the rotating drum, and rotating at a temperature of 50-53℃.

8. A process for production of high performance bovine crust leather based on salt free pickling, high pH value chrome tannage as claimed in claim 1, wherein, The drying finishing process comprises, in sequence, water squeezing and stretching, vacuum drying, air drying, moisture regaining, standing, and oscillation softening.

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