CN113201606A - Production process of heavy metal-free tanned cow leather - Google Patents

Abstract

The invention discloses a production process of heavy metal-free tanned cattle leather, which comprises the following steps: ash pelts → weighing (first → pre-deliming → main deliming → softening → washing → main tanning → cooperative tanning → standing → paring → weighing (second → processing (first → vibration softening)); the processing (I) comprises the following steps: softening → neutralizing → washing → filling → fatliquoring → standing → drying; the pre-deliming and main deliming processes adopt a degreasing agent, a deliming agent and a complexing agent; the main tanning process adopts an amphoteric organic compound; the synergistic tanning process adopts a phenolic synthetic tanning agent; the first step of neutralization adopts an amphoteric sulfonic fatliquor; the filling first procedure adopts sulfone synthetic tanning agents; the procedure of the fatting is to adopt a cationic fatting agent; the degreasing agent is a nonionic surfactant; the deliming agent is a mixture of ammonium salt and organic acid; the complexing agent is a polyphosphate complex.

Description

Production process of heavy metal-free tanned cow leather

Technical Field

The invention relates to the technical field of leather making, in particular to a production process of heavy metal-free tanned cattle leather.

Background

Chrome tanned leather has excellent stability against humidity and heat, rebound resilience, fullness, mechanical strength and the like, so that the chrome tanning method is still the most widely applied tanning method in the leather-making industry at present. However, with the continuous improvement of the industrialization degree, the environmental protection consciousness of consumers is continuously enhanced, and the problems of the shortage of chromium resources, the safety problem of chrome tanned products and the treatment problem of chromium-containing wastes (wastewater, waste leather scraps and the like) are receiving increasing attention. The EU countries even put forward 'chromium-free' requirements on partial interface leather and leather products thereof, so that the export of the leather and the leather products thereof in China is limited.

The chromium element is a heavy metal element with biological toxicity, and besides chromium, the limited heavy metal elements in the leather and leather products thereof also comprise mercury, cadmium, lead, metalloid arsenic and the like. Heavy metals can invade the human body through sweat impregnation and skin, and are harmful to human health; and heavy metals can not be completely absorbed by the leather in the process of leather production, and residual parts can be discharged in the form of waste water and solid wastes, so that the ecological environment is polluted.

Disclosure of Invention

The embodiment of the application provides a production process of the heavy metal-free tanned cattle leather, wherein an amphoteric organic compound and a phenol synthetic tanning agent are adopted to replace a chromium tanning agent, the adverse effects of heavy metal elements such as chromium on human health and ecological environment in the existing tanning technology are solved by controlling from the source, the heavy metal-free ecological cattle leather is obtained, the leather does not contain heavy metal elements such as trivalent chromium and hexavalent chromium which cause harm to human bodies and pollution to the environment, and the content of free formaldehyde accords with the restriction standard of European Union on formaldehyde in leather directly contacting with skin.

The embodiment of the application provides a production process of heavy metal-free tanned cattle leather, which comprises the following steps: ash pelts → weighing (first → pre-deliming → main deliming → softening → washing → main tanning → cooperative tanning → standing → paring → weighing (second → processing (first → vibration softening));

the processing (I) comprises the following steps: softening → neutralizing → washing → filling → fatliquoring → standing → drying;

the pre-deliming and main deliming processes adopt a degreasing agent, a deliming agent and a complexing agent;

the main tanning process adopts an amphoteric organic compound;

the synergistic tanning process adopts a phenolic synthetic tanning agent;

the first step of neutralization adopts an amphoteric sulfonic fatliquor;

the filling first procedure adopts sulfone synthetic tanning agents;

the procedure of the fatting is to adopt a cationic fatting agent;

the degreasing agent is a nonionic surfactant; the deliming agent is a mixture of ammonium salt and organic acid; the complexing agent is a polyphosphate complex.

Further, the amphiphilic organic complex is selected from the group consisting of Granofin Easy F-90 (stahl); the phenolic synthetic tanning agent is selected from at least one of Tanicor PWB (Stahl company) and Basyntan DLE (Basff chemical company); the amphoteric sulfonic fatliquor is selected from at least one of ODINIIL BTB (Spanish Delsa), BITOIL OPE (leather chemical company, Yonittaceae Italy), INGRASSANTE E123 (App chemical company, Italy); the sulfone syntan is at least one selected from Tanicor SXP (Stahl), BLANCOTAN BR (Guangzhou Schwarkout Co., Ltd.), BLANCOTAN BC (Guangzhou Schwarkout Co., Ltd.), and BLANCOTAN BRD (Guangzhou Schwarkout Co., Ltd.); the cationic fatliquor is selected from at least one of Catalix150 (Starl company) and INGRASSANTE M (App chemical company, Italy); the mixture of ammonium salt and organic acid is at least one selected from Decaltal U (Pasteur chemical Co.), TRUPOCAL DE (Thompler Co.), and DERMSAL ASB-A (Delry chemical Co.); the polyphosphate complex is at least one selected from TRUKALINK (thopler), CARETAN CR (mansion wangtong chemical materials limited). Further, the method also comprises a processing step II, wherein the processing step II is carried out after the oscillation softening step I;

the processing step II comprises the following steps: softening → neutralization → washing → filling → greasing → standing → drying → washing.

Further, the method further comprises the steps of dampening → shaking softening → coating, wherein the dampening → shaking softening → coating is performed after the step of treating (c).

Further, the pre-deliming process comprises the following specific steps: adding 80-100% of water, 0.1-0.15% of degreasing agent and 0.2-0.5% of deliming agent into the rotary drum, rotating for 30-35min at 30-32 ℃, wherein the pH value of bath liquid is 12-13;

the main deliming process comprises the following specific steps: adding 50-70% of water, 0.1-0.15% of degreasing agent, 0.15-0.3% of complexing agent and 2.5-3% of deashing agent into the rotary drum, rotating at 30-32 ℃ for 60-90min, and controlling the pH value of bath liquid to be 8.2-8.5.

Further, the softening process and the main deliming process are carried out in one bath, and the method specifically comprises the following steps: adding 0.15-0.3% trypsin into the bath lotion, and rotating for 30-35min to obtain bath lotion with pH of 8.2-8.5.

Further, the main tanning process comprises the following specific steps: adding 20-30% of water and 4-5% of amphoteric organic compound into the rotary drum, rotating at 30-35 ℃ for 150 min; adding 5-7% amphoteric organic compound, rotating for 480-720min, and controlling the pH of the bath liquid to 5.0-5.2; adding 30-50% of water, rotating at 40-45 deg.C for 150min, and controlling the pH of the bath solution at 4.8-4.9; adding 50-70% of water, rotating at 45-50 ℃ for 150min, and controlling the pH of the bath liquid to be 4.6-4.8;

the synergistic tanning process comprises the following specific steps: adding 80-100% of water, 1-1.5% of acid-resistant electrolyte-resistant fatting agent and 1-1.5% of dispersed tannin into the rotary drum, rotating at 30-35 deg.C for 10-15 min; supplementing 2.5-3% of phenolic synthetic tanning agent, and rotating for 120-; adding 1-1.5% formic acid 2-3 times, rotating for 20-25min, and bath solution pH is 2.8-3.0; adding 0.3-0.5% aluminum tanning agent, and rotating for 30-45 min; adding 0.15-0.2% of mildew preventive, and rotating for 30-45 min.

Further, the softening process is the same as the softening process, and the specific steps are as follows: adding 230 percent of 200 and 230 percent of water, 1 to 1.5 percent of sulfited fatliquor and 0.1 to 0.15 percent of degreasing agent into the rotary drum, rotating for 60 to 90min at the temperature of between 50 and 53 ℃;

the neutralization process is the same as the neutralization process, and the specific steps are as follows: adding 100-125% of water, 2-2.5% of amphoteric sulfonic fatliquor, 2-2.5% of neutralized tannin and 2-2.5% of ammonium carbonate into a rotary drum, rotating for 45-60min at the temperature of 30-32 ℃, and controlling the pH value of bath liquid to be 6.5-7.

Further, the filling (i) process includes the specific steps of: adding 30-50% of water, 2-2.5% of amphoteric sulfonic fatliquor, 2.5-3% of water-soluble acrylic polymer tanning agent, 2.5-3% of acrylic copolymer retanning agent and 0.5-1.0% of waterproof polymer into a rotary drum, rotating for 30-45min at the temperature of 30-32 ℃; adding 2.5-3% polyhydroxy synthetic tanning agent, and rotating for 60-90 min; adding 2-2.5% dispersed tannin, 8-10% phenol synthetic tanning agent, 8-10% melamine resin retanning agent, 8-10% aromatic sulfonate condensate retanning agent, 8-10% sulfone and aromatic sulfonate condensate synthetic tanning agent, and rotating for 60-90 min; 8-10% phenolsulfonic acid polycondensate retanning agent is added, and the mixture is rotated for 60-90 min; adding 4-4.5% sulfone synthetic tanning agent, and rotating for 60-90 min; adding 120 percent of 100-one, adding 2.5-3 percent of formic acid in 2-3 times, rotating for 25-30min at 50-53 ℃;

the step of fat liquoring comprises the following specific steps: adding 120-150% of water and 6-9% of cationic fatliquor into the rotary drum, rotating for 30-45min at the temperature of 50-53 ℃; adding 1-1.5% formic acid, and rotating for 30-45 min; adding 1-1.5% aluminum tanning agent, and rotating for 30-45 min.

Further, the filling step comprises the following specific steps: adding 30-50% water, 2-2.5% water soluble acrylic acid polymer tanning agent, 2-2.5% acrylic acid copolymer retanning agent, and 0.5-1.0% waterproof polymer into the rotary drum, rotating at 30-32 deg.C for 40-45 min; adding 2-2.5% polyhydroxy synthetic tanning agent, and rotating for 60-90 min; adding 1-1.5% dispersed tannin, 10-12% phenolic synthetic tanning agent, 3-5% phenolsulfonic acid polycondensate retanning agent, and 2-2.5% sulfone synthetic tanning agent, and rotating for 90-120 min; adding 120 percent of 100-one, adding 2.5-3 percent of formic acid in 2-3 times, rotating for 25-30min at 50-53 ℃;

the step of greasing comprises the following specific steps: 120-150% of water and 8-10% of cationic fatliquor, rotating for 30-45min at the temperature of 50-53 ℃; adding 2-2.5% of silicon synthetic fat liquor, and rotating for 30-45 min; adding 1-1.5% formic acid, and rotating for 30-45 min; adding 1-1.5% aluminum tanning agent, and rotating for 30-45 min.

Further, the drying process comprises the following specific steps: squeezing and stretching → vacuum drying → hanging and airing;

the weight of the ash pelts obtained in the weighing first procedure is used as the reference of the dosage of chemical materials in each procedure of pre-deliming, main deliming, softening, main tanning and synergistic tanning; and the weight of the wet white leather obtained in the weighing step is used as a reference for the amount of chemical materials in the processing steps.

One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

1. the main purpose of deliming is to remove Ca from the skin²⁺Eliminating expansion of the grey naked skin; in order to achieve 100% deliming of liming bare skin and prevent intradermal ash from influencing permeation and absorption of an amphoteric organic compound, the method adopts a mixture of ammonium salt and organic acid and a polyphosphate complex for synergistic deliming, the mixture of ammonium salt and organic acid has high deliming speed and high efficiency, and can be delimed with Ca²⁺Combining to form a soluble substance, and rapidly reducing the expansion of the grey naked skin; polyphosphate complexes to aid deliming with Ca²⁺The chelation reaction is carried out to generate soluble chelate, so that the grain surface of the naked skin is clean, flat, fine and compact after deliming.

2. The amphoteric organic compound can be mixed with-NH on collagen fiber₂The combination can also be combined with-COOH on the collagen fiber to strengthen the cross-linking structure of the collagen fiber, show good tanning effect and improve the moisture-heat resistance stability of the leather. After the main tanning is finished, a phenolic synthetic tanning agent is further adopted for synergistic tanning, so that the tanning effect is enhanced. The molecular structure of the phenolic synthetic tanning agent contains a large amount of-OH and-NH₂The active groups have good tanning property on one hand and can be combined with-NH on collagen fibers₂The groups of-COOH, -OH and the like react to form chemical crosslinking among collagen polypeptide chains, so that the moisture and heat resistance stability of the leather is improved; on the other hand, the phenolic synthetic tanning agent has excellent filling property, can be filled among collagen fibers in a physical adsorption mode, improves the compactness and fullness of leather, and reduces the loose surface rate.

3. The white wet leather obtained by the tanning of the amphoteric organic compound has extremely strong negative electricity property and absorption and combination capability on the traditional anionic retanning and fatliquoring materialsIs poor. The application adopts a sulfone synthetic tanning agent, an amphoteric sulfonic group fatting agent and a cation fatting agent, wherein the sulfone synthetic tanning agent is synthesized by taking phenol as a raw material and contains sulfone bridge bond (-SO)₂-) phenol polycondensate, the molecular structure of the synthetic tanning agent not only contains strong electron-withdrawing sulfuryl, but also contains sulfonic acid group (-SO)₃H) And phenolic hydroxyl (-OH) groups, which can react with-NH on collagen fibers of leather₂The groups of-COOH, -OH, NH-CO-and the like have different bonding effects, and the sulfone group can promote the dissociation of hydrogen atoms on the aromatic nucleus and further enhance the affinity of the synthetic tanning agent to collagen. The amphoteric sulfonic fatliquor and the cationic fatliquor can adjust the electrical property of the wet and white leather, are beneficial to the penetration and absorption of other retanning and fatliquoring materials, and endow the leather with good softness and oily touch feeling.

4. The tanning process is clean, simple and easy to operate, can release H + in the tanning process, automatically reduces the pH value of bath solution, directly tan the softened pelts, does not pickle in the early stage and does not extract alkali in the later stage, simplifies the tanning production process, avoids salt pollution in the pickling and alkali extraction processes, abandons a chromium tanning agent in the tanning process and avoids chromium pollution in the chromium tanning process. Compared with the traditional pickling and tanning process, the water consumption is reduced, the chemical materials are reduced, the tanning time is shortened, and the energy consumption and the operation error rate are effectively reduced.

5. The tearing force of the cattle leather with the thickness of 1.3-1.5mm of the traditional chrome-tanned upper leather is only required to be more than 36N. The thickness of the heavy metal-free tanned cattle leather prepared in the embodiment of the application is 1.3-1.5mm, and the tearing force can reach more than 65N. The formed leather has no obvious blood ribs and wrinkles, and the part between the ribs and the hips of the abdomen is plump and uniform; the crust leather has low extensibility and elasticity, and the grain surface is fine and compact.

Detailed Description

In order to better understand the technical solutions, the technical solutions will be described in detail with reference to the description and the specific embodiments.

Example 1:

a production process of heavy metal-free tanned cow leather comprises the following process flows:

(1) weighing the ash pelts, and putting the ash pelts into a rotary drum; (on a gray skin weight basis, assuming a gray skin weight of 1kg, then 0.1% degreaser, i.e., 0.001kg degreaser)

(2) Pre-deliming: adding 80% water, 0.1% degreasing agent Eusapon OC (Pasteur chemical Co.), and 0.2% deashing agent decatal U (Pasteur chemical Co.) into the rotary drum, rotating at 30 deg.C for 30min to obtain bath solution with pH of 12;

(3) main deashing: adding 50% of water, 0.1% of degreasing agent Eusapon OC (Pasteur chemical Co.), 0.15% of complexing agent TRUKALINK (Toeplier Co.), and 2.5% of deliming agent Decaltal U (Pasteur chemical Co.), rotating at 30 deg.C for 60min to obtain bath solution with pH of 8.5;

(4) softening: performing main deashing process in one bath, adding 0.15% trypsin DESOBEE U5 (Desel chemical industry Co., Ltd.), rotating for 30min, and bath solution pH is 8.5;

(5) main tanning: adding 20% water, 4% amphoteric organic complex Granofin Easy F-90 (Starter corporation) into the rotary drum, rotating at 30 deg.C for 120 min; supplementing 5% amphoteric organic complex Granofin Easy F-90 (Steyr), rotating for 480min, and bath pH 5.2; adding 30% water, rotating at 45 deg.C for 120min to obtain bath liquid with pH of 4.9; adding 50% water, rotating at 50 deg.C for 120min to obtain bath liquid with pH of 4.6;

(6) synergistic tanning: adding 80% water, 1% acid-resistant and electrolyte-resistant greasing agent TRUPON PEM (Thompler company) and 1% dispersed tannin Tamol M (Pasteur chemical company) into the rotary drum, rotating at 30 deg.C for 10 min; supplementing 2.5% of phenolic synthetic tanning agent Tanicor PWB (Steyr company), and rotating for 120 min; adding 1% formic acid in 2 times, rotating for 20min each time, and bath solution pH is 3.0; adding 0.3% aluminum tanning agent Lutan BN (Pasf chemical Co.), and rotating for 30 min; supplementing 0.15% mildew inhibitor BUSAN 1336 (Barkman corporation), and rotating for 30 min;

(7) standing to obtain wet white leather, shaving the wet white leather evenly and weighing the wet white leather; (0.1% degreaser, i.e. 0.001kg of degreaser, based on the weight of wet white leather assuming 1kg of wet white leather)

(8) Softening: adding 200% water, 1% sulfited fatliquor EDOLAN BZU (Spanish De Sha Bay Co., Ltd.), 0.1% degreaser Eusapon OC (Pasteur chemical Co., Ltd.) into the rotary drum, rotating at 50 deg.C for 60 min;

(9) and (3) neutralization: adding 100% water, 2% amphoteric sulfonic fatliquor ODINIOIL BTB (Spanish Desha, Inc.), 2% neutralizing tannin Tamol X NL (Starter, Inc.), 2% ammonium carbonate into the rotary drum, rotating at 30 deg.C for 60min, and bath pH 6.7;

(10) washing with water conventionally;

(11) filling: adding 30% water, 2% amphoteric sulfonic fatliquor ODINIIOL BTB (Spain Dessa Beck company), 2.5% water-soluble acrylic polymer tanning agent Relugan RF (Passion chemical company), 2.5% acrylic copolymer retanning agent TERGOTAN PMB (Stahl company), 0.5% water-proof polymer Densotan A (Passion chemical company) into the rotary drum, rotating for 30min at 30 ℃; supplementing 2.5% polyhydroxy synthetic tanning agent Basyntan EF (BASF chemical company), and rotating for 60 min; adding 2% dispersed tannin TamolM (Pasf chemical company), 8% phenolic synthetic tanning agent Tanicor PWB (Stahl company), 8% melamine resin retanning agent Relugan DLF (Pasf chemical company), 8% aromatic sulfonate condensate retanning agent Basyntan HL (Pasf chemical company), 8% sulfone and aromatic sulfonate condensate synthetic tanning agent Basyntan MLB (Pasf chemical company), and rotating for 60 min; 8 percent of phenolsulfonic acid polycondensate retanning agent Basyntan FR-BC (BASF chemical company) is added, and the mixture is rotated for 60 min; adding 4% of sulphone synthetic tanning agent Tanicor SXP (Steyr company), and rotating for 60 min; adding 100% of water, adding 2.5% of formic acid in 3 times, rotating for 30min each time, and keeping the temperature at 50 ℃;

(12) fat liquoring: adding 120% water and 6% cationic fatting agent Catalix150 (Stahl company) into the rotary drum, rotating for 30min at 50 ℃; adding 1% formic acid, and rotating for 30 min; adding 1% aluminum tanning agent Lutan BN (Pasf chemical company), and rotating for 30 min;

(13) standing; squeezing and stretching → vacuum drying → hanging and airing;

(14) vibrating and softening;

(15) softening is finished: the method is the same as the softening step;

(16) neutralization 2: the method is the same as the neutralization step;

(17) washing with water conventionally;

(18) filling step two: adding 30% water, 2% water-soluble acrylic polymer tanning agent Relugan RF (Passion chemical Co.), 2% acrylic copolymer retanning agent TERGOTAN PMB (Stahl), 0.5% water-proof polymer Densotan A (Passion chemical Co.), at 30 deg.C, and rotating for 40 min; supplementing 2% polyhydroxy synthetic tanning agent Basyntan EF (BASF chemical company), and rotating for 60 min; adding 1% dispersed tannin Tamol M (BASF chemical Co., Ltd.), 10% phenolic synthetic tanning agent Tanicor PWB (Staal Co., Ltd.), 3% phenolsulfonic acid polycondensate retanning agent Basyntan FR-BC (BASF chemical Co., Ltd.), 2% sulfone synthetic tanning agent Tanicor SXP (Staal Co., Ltd.), and rotating for 90 min; adding 100% of water, adding 2.5% of formic acid in 3 times, rotating for 30min each time, and keeping the temperature at 50 ℃;

(19) fat liquoring (II): adding 120% water and 8% cationic fatting agent Catalix150 (Stahl company) into the rotary drum, rotating for 30min at 50 ℃; supplementing 2% silicon synthetic fatliquor Densodrin CD (Basff chemical company), and rotating for 30 min; adding 1% formic acid, and rotating for 30 min; adding 1% aluminum tanning agent Lutan BN (Pasf chemical company), and rotating for 30 min;

(20) standing, drying, dampening, vibrating and softening, crust leather and coating by adopting conventional procedures.

The wet white leather obtained in the example was stored for 3 months without deterioration of wet heat resistance (Ts), mildew, and yellowing.

Example 2

A production process of heavy metal-free tanned cow leather comprises the following process flows:

(1) weighing the ash pelts, and putting the ash pelts into a rotary drum;

(2) pre-deliming: adding 90% of water, 0.13% of degreasing agent Eusapon OC (Passion chemical company) and 0.35% of deashing agent Decal U (Passion chemical company) into the rotary drum, rotating at 30 deg.C for 30min to obtain bath solution with pH of 12;

(3) main deashing: adding 60% of water, 0.13% of degreasing agent Eusapon OC (Pasteur chemical Co.), 0.23% of complexing agent TRUKALIN K (Toeplier Co.), and 2.75% of deliming agent Decatal U (Pasteur chemical Co.), rotating at 30 deg.C for 60min to obtain bath solution with pH of 8.5;

(4) softening: performing main deashing process in one bath, adding 0.23% trypsin DESOBEE U5 (Desel chemical industry Co., Ltd.), rotating for 30min, and bath solution pH is 8.5;

(5) main tanning: adding 25% water, 4.5% amphoteric organic complex Granofin Easy F-90 (Starter corporation) into the rotary drum, rotating at 30 deg.C for 120 min; supplementing 6% amphoteric organic complex Granofin Easy F-90 (Starl corporation), rotating for 480min, and bath pH 5.2; adding 40% water, rotating at 45 deg.C for 120min to obtain bath liquid with pH of 4.9; adding 60% water, rotating at 50 deg.C for 120min to obtain bath liquid with pH of 4.6;

(6) synergistic tanning: adding 90% water, 1.25% acid-resistant and electrolyte-resistant fatliquor TRUPON PEM (Toeplier corporation) and 1.25% dispersed tannin Tamol M (Basf chemical corporation) into the rotary drum, rotating at 30 deg.C for 10 min; supplementing 2.75% of phenolic synthetic tanning agent Tanicor PWB (Steyr company), and rotating for 120 min; adding 1.25% formic acid in 2 times, rotating for 20min each time, and bath solution pH is 3.0; adding 0.4% aluminum tanning agent Lutan BN (Pasf chemical Co.), and rotating for 30 min; supplementing 0.18% mildew inhibitor BUSAN 1336 (Barkman corporation), and rotating for 30 min;

(7) standing to obtain wet white leather, shaving the wet white leather evenly and weighing the wet white leather;

(8) softening: adding 215% water, 1.25% sulfited fatliquor EDOLAN BZU (Spanish Delsa Beaud.), 0.13% degreaser Eusapon OC (Pasteur chemical Co.) into the drum, rotating at 50 deg.C for 60 min;

(9) and (3) neutralization: adding 113% water, 2.25% amphoteric sulfonic fatliquor ODINIION BTB (Spanish Desha, Inc.), 2.25% neutralized tannin Tamol X NL (Steyr, Inc.), 2.25% ammonium carbonate into a rotary drum, rotating at 30 deg.C for 60min, and bath pH 6.7;

(10) washing with water conventionally;

(11) filling: adding 40% of water, 2.25% of amphoteric sulfonic fatliquor ODINIOL BTB (Spanish Delsa), 2.75% of water-soluble acrylic polymer tanning agent Relugan RF (Passion chemical Co., Ltd.), 2.75% of acrylic copolymer retanning agent TERGOTAN PMB (Staal Co., Ltd.), 0.75% of water-repellent polymer Densotan A (Passion chemical Co., Ltd.) to a rotary drum, rotating at 30 ℃ for 30 min; supplementing 2.75% polyhydroxy synthetic tanning agent Basyntan EF (BASF chemical company), and rotating for 60 min; adding 2.25% dispersed tannin Tamol M (Pasf chemical company), 9% phenolic synthetic tanning agent Tanicor PWB (Stahl company), 9% melamine resin retanning agent Relugan DLF (Pasf chemical company), 9% aromatic sulfonate condensate retanning agent Basyntan HL (Pasf chemical company), 9% sulfone and aromatic sulfonate condensate synthetic tanning agent Basyntan MLB (Pasf chemical company), and rotating for 60 min; supplementing 9% of phenolsulfonic acid polycondensate retanning agent Basyntan FR-BC (BASF chemical company), and rotating for 60 min; adding 4.25% of Tanicor SXP (Steyr company), and rotating for 60 min; adding 110% of water, adding 2.75% of formic acid in 3 times, rotating for 30min each time, and keeping the temperature at 50 ℃;

(12) fat liquoring: adding 135% of water and 7.5% of cationic fatliquor Catalix150 (Stahl company) into the rotary drum, rotating for 30min at 50 ℃; adding 1.25% formic acid, and rotating for 30 min; adding 1.25% aluminum tanning agent Lutan BN (Pasf chemical Co.), and rotating for 30 min;

(13) standing; squeezing and stretching → vacuum drying → hanging and airing;

(14) vibrating and softening;

(15) softening is finished: the method is the same as the softening step;

(16) neutralization 2: the method is the same as the neutralization step;

(17) washing with water conventionally;

(18) filling step two: adding 40% water, 2.25% water-soluble acrylic polymer tanning agent Relugan RF (Passion chemical Co.), 2.25% acrylic copolymer retanning agent TERGOTAN PMB (Stahl), 0.75% water-proof polymer Densotan A (Passion chemical Co.), at 30 deg.C, and rotating for 40 min; supplementing 2.25% polyhydroxy synthetic tanning agent Basyntan EF (BASF chemical company), and rotating for 60 min; adding 1.25% dispersed tannin Tamol M (BASF chemical company), 11% phenolic synthetic tanning agent Tanicor PWB (Stall company), 4% phenolsulfonic acid polycondensate retanning agent Basyntan FR-BC (BASF chemical company) and 2.25% sulfone synthetic tanning agent Tanicor SXP (Stall company), and rotating for 90 min; adding 110% of water, adding 2.75% of formic acid in 3 times, rotating for 30min each time, and keeping the temperature at 50 ℃;

(19) fat liquoring (II): adding 135% of water and 9% of cationic fatting agent Catalix150 (Stahl company) into the rotary drum, rotating for 30min at the temperature of 50 ℃; supplementing 2.25% silicon synthetic fatliquor Densodrin CD (basf chemical company), and rotating for 30 min; adding 1.25% formic acid, and rotating for 30 min; adding 1.25% aluminum tanning agent Lutan BN (Pasf chemical Co.), and rotating for 30 min;

(20) standing, drying, dampening, vibrating and softening, crust leather and coating by adopting conventional procedures.

The wet white leather obtained in the example was stored for 3 months without deterioration of wet heat resistance (Ts), mildew, and yellowing.

Example 3:

a production process of heavy metal-free tanned cow leather comprises the following process flows:

(1) weighing the ash pelts, and putting the ash pelts into a rotary drum;

(2) pre-deliming: adding 100% water, 0.15% degreasing agent Eusapon OC (Pasteur chemical Co.), and 0.5% deashing agent Decal U (Pasteur chemical Co.) into the rotary drum, rotating at 30 deg.C for 30min to obtain bath solution with pH of 12;

(3) main deashing: adding 70% water, 0.15% degreasing agent Eusapon OC (Pasteur chemical Co.), 0.3% complexing agent TRUKALIN K (Toeplier Co.), and 3% deliming agent decatal U (Pasteur chemical Co.) into the rotary drum, rotating at 30 deg.C for 60min to obtain bath solution pH of 8.5;

(4) softening: performing main deashing process in one bath, adding 0.3% trypsin DESOBEE U5 (Desel chemical industry Co., Ltd.), rotating for 30min, and bath solution pH of 8.5;

(5) main tanning: adding 30% water and 5% amphoteric organic complex Granofin Easy F-90 (Starter corporation) into the rotary drum, rotating at 30 deg.C for 120 min; supplementing 7% amphoteric organic complex Granofin Easy F-90 (Steyr), rotating for 480min, and bath pH 5.2; adding 50% water, rotating at 45 deg.C for 120min to obtain bath liquid with pH of 4.9; adding 70% water, rotating at 50 deg.C for 120min to obtain bath liquid with pH of 4.6;

(6) synergistic tanning: adding 100% water, 1.5% acid-resistant and electrolyte-resistant greasing agent TRUPON PEM (Toeplier corporation) and 1.5% dispersed tannin Tamol M (Basf chemical company) into a rotary drum, rotating at 30 deg.C for 10 min; supplementing 3% of phenolic synthetic tanning agent Tanicor PWB (Steyr corporation), and rotating for 120 min; adding 1.5% formic acid in 2 times, rotating for 20min each time, and bath solution pH is 3.0; adding 0.5% aluminum tanning agent Lutan BN (Pasf chemical Co.), and rotating for 30 min; supplementing 0.2% mildew inhibitor BUSAN 1336 (Barkman corporation), and rotating for 30 min;

(7) standing to obtain wet white leather, shaving the wet white leather evenly and weighing the wet white leather;

(8) softening: adding 230% water, 1.5% sulfited fatliquor EDOLAN BZU (Spanish Delsa Beaud.), 0.15% degreaser Eusapon OC (Pasteur chemical Co.) into the drum, rotating at 50 deg.C for 60 min;

(9) and (3) neutralization: adding 125% water, 2.5% amphoteric sulfonic fatliquor ODINIION BTB (Spanish Desha, Inc.), 2.5% neutralized tannin Tamol X NL (Steyr, Inc.), 2.5% ammonium carbonate into a rotary drum, rotating at 30 deg.C for 60min, and bath pH 6.7;

(10) washing with water conventionally;

(11) filling: adding 50% water, 2.5% amphoteric sulfonic fatliquor ODINIOL BTB (Spain Dessa Beck company), 3% water-soluble acrylic polymer tanning agent Relugan RF (Passion chemical company), 3% acrylic copolymer retanning agent TERGOTAN PMB (Stahl company), 1% water-proof polymer Densotan A (Passion chemical company), rotating at 30 deg.C for 30 min; supplementing 3% polyhydroxy synthetic tanning agent Basyntan EF (BASF chemical company), and rotating for 60 min; adding 2.5% dispersed tannin TamolM (Pasf chemical company), 10% phenolic synthetic tanning agent Tanicor PWB (Stahl company), 10% melamine resin retanning agent Relugan DLF (Pasf chemical company), 10% aromatic sulfonate condensate retanning agent Basyntan HL (Pasf chemical company), 10% sulfone and aromatic sulfonate condensate synthetic tanning agent Basyntan MLB (Pasf chemical company), and rotating for 60 min; adding 10% of phenolsulfonic acid polycondensate retanning agent Basyntan FR-BC (BASF chemical company), and rotating for 60 min; adding 4.5% of Tanicor SXP (Steyr company), and rotating for 60 min; adding 110% of water, adding 3% of formic acid in 3 times, rotating for 30min each time at 50 ℃;

(12) fat liquoring: adding 150% water and 9% cationic fatting agent Catalix150 (Stahl company) into the rotary drum, rotating for 30min at 50 deg.C; adding 1.5% formic acid, and rotating for 30 min; adding 1.5% aluminum tanning agent Lutan BN (Pasf chemical Co.), and rotating for 30 min;

(13) standing; squeezing and stretching → vacuum drying → hanging and airing;

(14) vibrating and softening;

(15) softening is finished: the method is the same as the softening step;

(16) neutralization 2: the method is the same as the neutralization step;

(17) washing with water conventionally;

(18) filling step two: adding 50% water, 2.5% water-soluble acrylic polymer tanning agent Relugan RF (Passion chemical Co.), 2.5% acrylic copolymer retanning agent TERGOTAN PMB (Stahl), 1% water-proof polymer Densotan A (Passion chemical Co.), at 30 deg.C, and rotating for 40 min; supplementing 2.5% polyhydroxy synthetic tanning agent Basyntan EF (BASF chemical company), and rotating for 60 min; adding 1.5% dispersed tannin Tamol M (BASF chemical company), 12% phenolic synthetic tanning agent Tanicor PWB (Stall company), 5% phenolsulfonic acid polycondensate retanning agent Basyntan FR-BC (BASF chemical company) and 2.5% sulfone synthetic tanning agent Tanicor SXP (Stall company), and rotating for 90 min; adding 120% of water, adding 3% of formic acid in 3 times, rotating for 30min each time at 50 ℃;

(19) fat liquoring (II): adding 150% water and 10% cationic fatting agent Catalix150 (Stahl company) into the rotary drum, rotating for 30min at 50 deg.C; supplementing 2.5% silicon synthetic fatliquor Densodrin CD (basf chemical company), and rotating for 30 min; adding 1.5% formic acid, and rotating for 30 min; adding 1.5% aluminum tanning agent Lutan BN (Pasf chemical Co.), and rotating for 30 min;

(20) standing, drying, dampening, vibrating and softening, crust leather and coating by adopting conventional procedures.

The wet white leather obtained in the example was stored for 3 months without deterioration of wet heat resistance (Ts), mildew, and yellowing.

Experimental detection

The main tanning process of this example 1 was compared to a conventional pickling tanning process as shown in table 1 below:

TABLE 1

As can be seen from Table 1, this example 1 omits the pickling process because the tanning process of the example releases H + so that the bath pH automatically decreases; meanwhile, compared with the traditional pickling and tanning process, the water consumption is reduced, chemical materials are reduced, the tanning time is shortened, and the energy consumption and the operation error rate can be effectively reduced.

The cow leather obtained in examples 1, 2 and 3 was subjected to experimental tests, and the test results are shown in table 2 below:

TABLE 2

Note: testing heavy metals (or metalloids) includes: 14 kinds of lead, cadmium, nickel, chromium, cobalt, copper, antimony, mercury, silver, iron, zirconium, titanium, arsenic and selenium;

n.d. not detected (< MDL);

③ MDL ═ method detection limit;

the free formaldehyde content meets the European standards for the formaldehyde in leathers in direct contact with the skin (75 kg/mg).

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.

Claims (10)

1. The production process of the heavy metal-free tanned cattle leather is characterized by comprising the following steps: ash pelts → weighing (first → pre-deliming → main deliming → softening → washing → main tanning → cooperative tanning → standing → paring → weighing (second → processing (first → vibration softening));

the processing (I) comprises the following steps: softening → neutralizing → washing → filling → fatliquoring → standing → drying;

the pre-deliming and main deliming processes adopt a degreasing agent, a deliming agent and a complexing agent;

the main tanning process adopts an amphoteric organic compound;

the synergistic tanning process adopts a phenolic synthetic tanning agent;

the first step of neutralization adopts an amphoteric sulfonic fatliquor;

the filling first procedure adopts sulfone synthetic tanning agents;

the procedure of the fatting is to adopt a cationic fatting agent;

the degreasing agent is a nonionic surfactant; the deliming agent is a mixture of ammonium salt and organic acid; the complexing agent is a polyphosphate complex.

2. The process for producing heavy metal-free tanned bovine leather according to claim 1,

the method also comprises a processing step II, wherein the processing step II is carried out after the oscillation softening step I;

the processing step II comprises the following steps: softening → neutralization → washing → filling → greasing → standing → drying → washing.

3. The process for producing heavy metal-free tanned bovine leather according to claim 1, further comprising dampening → shaking softening → finishing, wherein the dampening → shaking softening → finishing is carried out after the treating step.

4. The process for producing heavy metal-free tanned bovine leather according to claim 1,

the pre-deliming process comprises the following specific steps: adding 80-100% of water, 0.1-0.15% of degreasing agent and 0.2-0.5% of deliming agent into the rotary drum, rotating at 30-32 ℃, and controlling the pH of bath liquid to be 12-13;

the main deliming process comprises the following specific steps: adding 50-70% of water, 0.1-0.15% of degreasing agent, 0.15-0.3% of complexing agent and 2.5-3% of deashing agent into the rotary drum, rotating at 30-32 ℃, and controlling the pH of bath liquid to be 8.2-8.5.

5. The process for producing heavy metal-free tanned bovine leather according to claim 1,

the softening process and the main deliming process are carried out in one bath, and the method comprises the following specific steps: adding 0.15-0.3% trypsin into the bath liquid, and rotating to obtain bath liquid with pH of 8.2-8.5.

6. The process for producing heavy metal-free tanned bovine leather according to claim 1,

the main tanning process comprises the following specific steps: adding 20-30% of water and 4-5% of amphoteric organic compound into the rotary drum, rotating at 30-35 deg.C; adding 5-7% of amphoteric organic compound, and rotating to obtain bath liquid with pH of 5.0-5.2; adding 30-50% water, rotating at 40-45 deg.C, and bath solution pH of 4.8-4.9; adding 50-70% of water, rotating at 45-50 deg.C, and bath solution pH is 4.6-4.8;

the synergistic tanning process comprises the following specific steps: adding 80-100% of water, 1-1.5% of acid-resistant electrolyte-resistant fatting agent and 1-1.5% of dispersed tannin into the rotary drum, rotating at the temperature of 30-35 ℃; adding 2.5-3% of phenolic synthetic tanning agent, and rotating; adding 1-1.5% formic acid 2-3 times, rotating, and bath solution pH 2.8-3.0; adding 0.3-0.5% of aluminum tanning agent, and rotating; adding 0.15-0.2% of mildew preventive, and rotating.

7. The process for producing heavy metal-free tanned bovine leather according to claim 1,

the softening process is the same as the softening process, and the specific steps are as follows: adding 200-230% of water, 1-1.5% of sulfited fatliquor and 0.1-0.15% of degreasing agent into the rotary drum, rotating at the temperature of 50-53 ℃;

the neutralization process is the same as the neutralization process, and the specific steps are as follows: adding 100-125% of water, 2-2.5% of amphoteric sulfonic fatliquor, 2-2.5% of neutralized tannin and 2-2.5% of ammonium carbonate into a rotary drum, rotating at the temperature of 30-32 ℃, and controlling the pH value of bath liquid to be 6.5-7.

8. The process for producing heavy metal-free tanned bovine leather according to claim 1,

the filling first process comprises the following specific steps: adding 30-50% of water, 2-2.5% of amphoteric sulfonic fatliquor, 2.5-3% of water-soluble acrylic polymer tanning agent, 2.5-3% of acrylic copolymer retanning agent and 0.5-1.0% of waterproof polymer into a rotary drum, rotating at the temperature of 30-32 ℃; adding 2.5-3% polyhydroxy synthetic tanning agent, and rotating; adding 2-2.5% of dispersed tannin, 8-10% of phenol synthetic tanning agent, 8-10% of melamine resin retanning agent, 8-10% of aromatic sulfonate condensate retanning agent, 8-10% of sulfone and aromatic sulfonate condensate synthetic tanning agent, and rotating; 8-10% of phenolsulfonic acid polycondensate retanning agent is added, and the mixture is rotated; adding 4-4.5% of sulfone synthetic tanning agent, and rotating; adding 120 percent of 100-one water, adding 2.5-3 percent of formic acid in 2-3 times, rotating at 50-53 ℃;

the step of fat liquoring comprises the following specific steps: adding 120-150% of water and 6-9% of cationic fatliquor into the rotary drum, rotating at the temperature of 50-53 ℃; adding 1-1.5% formic acid, and rotating; adding 1-1.5% aluminum tanning agent, and rotating.

9. The process for producing heavy metal-free tanned bovine leather according to claim 1,

the filling step comprises the following specific steps: adding 30-50% of water, 2-2.5% of water-soluble acrylic polymer tanning agent, 2-2.5% of acrylic copolymer retanning agent and 0.5-1.0% of waterproof polymer into a rotary drum, rotating at 30-32 ℃; adding 2-2.5% polyhydroxy synthetic tanning agent, and rotating; adding 1-1.5% of dispersed tannin, 10-12% of phenol synthetic tanning agent, 3-5% of phenolsulfonic acid polycondensate retanning agent and 2-2.5% of sulfone synthetic tanning agent, and rotating; adding 120 percent of 100-one water, adding 2.5-3 percent of formic acid in 2-3 times, rotating at 50-53 ℃;

the step of greasing comprises the following specific steps: 120-150% of water and 8-10% of cationic fatliquor, rotating at the temperature of 50-53 ℃; adding 2-2.5% of silicon synthetic fat liquor, and rotating; adding 1-1.5% formic acid, and rotating; adding 1-1.5% aluminum tanning agent, and rotating.

10. The process for producing heavy metal-free tanned bovine leather according to claim 1,

the drying process comprises the following specific steps: squeezing and stretching → vacuum drying → hanging and airing;

the weight of the ash pelts obtained in the weighing first procedure is used as the reference of the dosage of chemical materials in each procedure of pre-deliming, main deliming, softening, main tanning and synergistic tanning; and the weight of the wet white leather obtained in the weighing step is used as a reference for the amount of chemical materials in the processing steps.