Tanning device and process for full vegetable tanning cowhide harness leather

Abstract

The invention discloses a tanning device for full vegetable tanning cowhide harness leather, and relates to the technical field of leather processing. According to the leather tanning device for the full vegetable tanned cow leather harness, an automatic leather conveying system is constructed through the conveying shaft and the conveying belt, uniform and continuous feeding is achieved, and the treatment consistency is improved; a high-pressure fixed spray head arranged in the leather soaking treatment system can be used for carrying out efficient and uniform jet flow treatment on leather, so that the treatment efficiency and quality are obviously improved, meanwhile, the consumption of water, electricity and chemical materials is reduced, and the generation of sewage is reduced; a filter wheel, a dust cover, a rotating shaft, a bearing and other components are arranged in the sewage purification system, and production sewage can be efficiently purified; purified water is recycled for production through a purified water outlet, so that resource recycling is realized, and residual sludge is intensively discharged through a drain outlet; and the exhaust treatment system is communicated with the wastewater tank, so that irritant gas and pollutants can be discharged in time, air circulation in the device is maintained, and the working environment is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of leather processing, and in particular to a tanning device and process for full plant tanning of cowhide harness leather. BACKGROUND

[0002] Tanning treatment is a key chemical process for converting cowhide, a perishable protein material, into stable and durable cowhide harness leather with practical value. This process not only fundamentally overcomes the defect of perishable rawhide, but also endows the leather with corrosion resistance, structural stability, heat and water resistance, softness and ductility, excellent physical and mechanical properties, and dyeing and finishing properties. Among various tanning methods, plant tanning uses tannins in plant extracts to combine with collagen fibers, which is a tanning strategy with wide raw material sources, low cost and environmental friendliness. At the same time, plant tanning can effectively avoid the bottleneck problem that the firmness, fastness and easy shaping of the leather caused by chrome tanning and aldehyde tanning cannot meet the performance requirements of cowhide harness leather.

[0003] Traditional plant tanning processes mostly use pit tanning, while modern plant tanning generally uses drum tanning. The latter has made significant progress in shortening the tanning cycle, improving production efficiency, reducing labor intensity and saving space. However, even this relatively advanced technology of drum tanning has obvious bottlenecks: usually only 60%-70% of the tanning agent combines with collagen protein and remains in the skin, and the remaining 30%-40% of the tanning agent is discharged with waste liquid, resulting in serious waste of raw materials. In addition, the chemical oxygen demand (COD) and suspended solids (SS) content in such waste liquid are extremely high, greatly increasing the difficulty of wastewater treatment, not only requiring more reagents, energy consumption and treatment cost, but also significantly increasing the environmental emission load of the whole process.

[0004] Under the background of the current national active promotion of green transformation of traditional industries, the leather-making industry urgently needs to develop in the direction of green and low carbon. In order to improve the market competitiveness of high-value-added products such as chrome-free tanning, achieve precise carbon reduction in the whole tanning process and sustainable development of enterprises, it has become a key to the transformation and upgrading of the industry to develop a tanning process and device for full plant tanning of cowhide harness leather with high efficiency, low pollution, low energy consumption and high quality. SUMMARY

[0005] The purpose of the present application is to provide a tanning device for full plant tanning of cowhide harness leather, which solves the above problems.

[0006] To solve the above technical problems, the present application adopts the following technical solutions:

[0007] The tanning device for full plant tanning of cowhide harness leather of the present application comprises a trough, a treatment chamber, a wastewater tank, a leather area conveying system, a leather soaking treatment system, a sewage purification system and an exhaust treatment system.

[0008] The material tank is arranged outside the processing chamber, and the wastewater tank is arranged inside the processing chamber.

[0009] The leather area conveying system comprises a conveying frame, one end of the conveying frame is arranged beside the material tank through a through hole arranged on one side of the processing chamber, the conveying frame is arranged above the wastewater tank, and a plurality of conveying shafts and conveying belts surrounding the conveying shafts are connected to the conveying frame.

[0010] The leather soaking treatment system is arranged on one side of the processing chamber, the leather soaking treatment system comprises a circulating pump arranged on one side of the processing chamber, the circulating pump is a high-pressure pump, a chemical material injection mechanism for injecting chemical materials into water flow in proportion is further arranged in the outlet pipeline of the circulating pump, the circulating pump is connected to the water outlet pipe of the sewage purification system through a purified water inlet, a purified water pipeline is connected to the water outlet end of the circulating pump, the purified water pipeline is arranged above the conveying belt and is fixed to the inner top surface of the processing chamber, a plurality of spray heads are arranged on the purified water pipeline, and the spray heads are high-pressure rotary spray heads.

[0011] The wastewater tank is provided with a sewage purification port, and the water inlet pipe of the sewage purification system is connected to the wastewater tank through the sewage purification port.

[0012] The air exhaust treatment system is arranged on the other side of the processing chamber.

[0013] Further, the conveying belt is in a mesh structure, and a liquid collecting tank for collecting dripping liquid is arranged below the conveying belt, and the liquid collecting tank is communicated with the wastewater tank.

[0014] Further, the sewage purification system comprises a filter box and a filter wheel arranged in the filter box, the filter wheel is rotatably connected to the filter box through a rotating shaft and a bearing, the filter box is provided with a purified water outlet, a sewage inlet and a sewage discharge port, the filter box is connected to the purified water inlet of the circulating pump through the purified water outlet, the filter box is connected to the sewage purification port through the sewage inlet, and a dust cover is further arranged in the filter box and covers the periphery of the filter wheel.

[0015] Further, the air exhaust treatment system comprises an air exhaust cover, a fan and an exhaust pipeline, the air exhaust cover is arranged at the inner top end of the processing chamber, the air exhaust cover and one end of the exhaust pipeline are connected through an exhaust gas purification mechanism, and the other end of the exhaust pipeline is connected to the air inlet of the fan.

[0016] A tanning process of a tanning device for tanning full-plant-tanned cowhide harness leather, characterized in that the process comprises the following steps:

[0017] A, the pre-treatment of raw hide: the raw hide is placed in a rotating drum, water and soaking aids are added, and rotation is continued until the water absorption recovers to the fresh hide state; the flesh side of the soaked hide is polished to remove the meat membrane, and then placed in an enzyme-containing neutral solution for rotation to remove hair, and then placed in a cool place for static placement; lime soaking aids and lime are added in sequence, and continuous rotation is performed to complete lime soaking; a hide splitting machine is used, and the thickness of the split hide is adjusted according to requirements to uniformly divide the hide into the required thickness; the split hide is placed in a solution containing ammonium chloride and ammonium sulfate, and is rotated to remove lime, and then washed with clean water to remove residual lime;

[0018] B, acid pickling and pre-tanning: the pre-treated raw hide is placed in water, and first to fourth pre-tanning chemicals are added in sequence and continuously rotated; during the acid pickling and pre-tanning process, a recovery liquid collection and filtration device is provided, and a spraying machine is used for chemical liquid circulation;

[0019] C, tannage by tanning plant: the raw hide to be treated is transported into the treatment chamber of the leather soaking treatment system through a trough and a leather area conveying system, a circulating pump is started, and a first tanning plant tanning chemical is added through a chemical adding mechanism, the purified water from the sewage purification system is mixed with the chemical, and then sprayed into the leather through a high-pressure nozzle, the spraying time is 30 minutes, the waste water generated during the treatment is introduced into the sewage purification system through a sewage inlet for purification treatment, the purified water is circulated back to the inlet of the circulating pump, the waste gas generated during the treatment is collected and discharged by the exhaust treatment system, and then the above-mentioned actions are repeated, and a second tanning plant tanning chemical, a third tanning plant tanning chemical and a fourth tanning plant tanning chemical are added respectively to treat the leather;

[0020] D, intermediate treatment: the leather blank after tannage by tanning plant is taken out of the rotating drum, and is placed for 120 minutes for static treatment to remove excess surface water, and then the static leather blank is squeezed to remove excess internal water, preparing for subsequent deep processing;

[0021] E, retanning and rinsing: the retanning process is to place the leather blank after tannage by tanning plant into a rotating drum, and then add a dispersing agent, a retanning agent and a filler in sequence and rotate, and a recovery liquid collection and chemical adding filtration device is provided, and a spraying machine is used for chemical liquid circulation. The rinsing process is to add an acidic aid and a multifunctional aid to adjust the pH value and activate the surface, and then water is used to remove residual tanning agent, grease and impurities on the leather blank;

[0022] F, oiling and acid fixing: the oiling process is to place the leather blank after retanning into a rotating drum, add water, a composite grease agent and a mildew-proof agent to ensure uniform penetration of the grease into the leather fibers; the acid fixing process is to add formic acid into the rotating drum in multiple times based on fixed time intervals, maintain the temperature and pH value of the solution stable, and realize the synergistic optimization of grease fixation and pH adjustment of the leather blank;

[0023] G, hanging and stretching: after the oiling and acid fixing, the leather blank is taken out of the drum, and the flesh side of the leather blank is placed in a relative overlapping manner;

[0024] Let stand: Let stand at room temperature for 3-5 days to allow the moisture and oil to distribute evenly;

[0025] Dehydration: A hydraulic dehydrator is used at a pressure of 0.3-0.5 MPa to remove excess water to a moisture content of 45%-50%, in preparation for drying.

[0026] Hanging and drying: Hang the squeezed-out leather on a drying rack and hang it in a well-ventilated environment at 28-30℃ for 4 hours;

[0027] Drying: After hanging in a ventilated area to dry, raise the temperature to 40-45℃ and continue drying until the moisture content is 18%-22%;

[0028] Stretching: Use a rotary drum stretching machine to stretch the skin to make the surface of the skin flat and the grain smooth, eliminating wrinkles;

[0029] Vibration softening: High-frequency vibration of a vibration softener loosens the fibers, giving the leather a soft feel;

[0030] Roll pressing: Performed on a roller press at a pressure of 1.0-1.2 MPa, which makes the skin compact, the grain surface smooth, and improves wear resistance and gloss.

[0031] Upon arrival at the warehouse: After the moisture content is tested and found to be within the standard range, stack the items flat and place them in the warehouse, keeping the environment well-ventilated and dry;

[0032] The hanging and drying process specifically includes: Day 1: temperature 25 ℃, humidity 70-80%; Day 2: temperature 30 ℃, humidity 60-70%; Day 3: temperature 35 ℃, humidity 40-50%.

[0033] Furthermore, the soaking aids used in the pretreatment of raw hides include 1% Ciartan multifunctional aid, 1% degreasing agent, 2% soaking enzyme preparation, and 4% sodium chloride. The 1% degreasing agent is any two of ZL300, D117, and TJ-A160 used in combination. The enzyme-containing neutral solution used includes 2% protease, 1% lipase, 1.5% ammonium sulfate, and 0.5% nonionic surfactant. The liming aid used includes a 1% sodium sulfide and sodium hydroxide mixed alkaline solution.

[0034] Furthermore, in the pickling and pretanning process, the first to fourth pretanning chemicals include 1% water softener, 0.5% anti-snagging agent, 4% dispersed tannin and 4% phenol tannin. The 1% water softener includes sodium hexametaphosphate and sodium pyrophosphate. The 0.5% anti-snagging agent includes a solid composite lubricant composed of polymer wax, aluminum stearate, calcium stearate and Seta_SLP.

[0035] Further, the first vegetable tanning agent in the vegetable tanning process comprises 50% multi-type tannin, the 50% multi-type tannin is any two of gallic tannin, quercetin tannin and flavonoid tannin, the second vegetable tanning agent comprises 1% light-resistant oil, the 1% light-resistant oil comprises nitrocellulose water-based emulsion light oil and water-based polyurethane light-resistant oil, the third vegetable tanning agent comprises 2% dispersed tannin, and the fourth vegetable tanning agent comprises 5% phenolic tannin.

[0036] Further, the dispersing agent in the retanning and rinsing process is 2% dispersed tannin, the retanning agent is 2% composite sulfone tanning agent, the 2% composite sulfone tanning agent is any two of aryl sulfone bridge type tanning agent, aryl sulfone type amphoteric tanning agent and yellowing-resistant sulfone type tannin tanning agent, the filler is 2% melamine, the acidic auxiliary agent is 1% formic acid and 3% maleic anhydride, and the multifunctional auxiliary agent is 1% ciartan multifunctional auxiliary agent.

[0037] Further, the composite oil agent in the oiling and acid fixing process is 3% light-resistant oil, 3% modified beef tallow, 2% sulfurized fish oil and 2% penetrating oil, the mildew-proof agent is 1% prochloraz, the amount of formic acid used in the acid fixing process is 0.1% at a time, the number of times of use is 5, and the pH value is stabilized at 3.5-3.8.

[0038] Compared with the prior art, the present application has the beneficial technical effects that:

[0039] The full-vegetable tanned cowhide leather harness leather tanning device provided by the present application realizes uniform and continuous feeding by constructing an automatic leather conveying system through a conveying shaft and a conveying belt, improves processing consistency, the high-pressure fixed nozzle arranged in the leather soaking treatment system can perform efficient and uniform jet flow treatment on the leather, significantly improves processing efficiency and quality, reduces water, electricity and chemical material consumption, and reduces sewage generation, the sewage purification system is internally provided with components such as a filter wheel, a dust cover, a rotating shaft and a bearing, and can efficiently purify production sewage, the purified water is returned to production through a purified water outlet, resource recycling is realized, and residual sludge is discharged through a sewage discharge port, the exhaust treatment system is communicated with the wastewater tank, can timely remove irritating gases and pollutants, maintains internal air circulation of the device, and improves the working environment.

[0040] Meanwhile, the present application optimizes the production process, improves the vegetable tanning effect, greatly reduces wastewater discharge and promotes the realization of the goal of low carbon or even zero carbon emission, the present application can shorten the tanning time by 40-50%, reduce the hot water consumption by 60-70%, reduce the energy consumption by 30-40%, reduce the mechanical and chemical damage to raw leather, improve the finished product grade rate, significantly save chemical raw materials by 30-40%, reduce water consumption by 50-60%, reduce electric energy consumption by 20-30%, and greatly reduce the generation of sewage and sludge from the source. BRIEF DESCRIPTION OF DRAWINGS

[0041] The present invention will be further described below with reference to the accompanying drawings.

[0042] Figure 1 This is a top view of the tanning apparatus for the all-vegetable tanned cowhide fittings of the present invention;

[0043] Figure 2 This is a schematic diagram of a wastewater purification system.

[0044] Figure 3 This is a flow chart of the tanning process for the all-vegetable tanned cowhide fitting leather of the present invention;

[0045] Explanation of reference numerals in the attached drawings: 1. Material trough; 2. Conveyor shaft; 3. Conveyor belt; 4. Processing chamber; 5. Wastewater tank; 6. Circulating pump; 7. Purified water pipeline; 8. Purified water inlet; 9. Wastewater purification outlet; 10. Nozzle; 11. Exhaust hood; 12. Fan; 13. Waste discharge pipeline; 14. Purified water outlet; 15. Wastewater inlet; 16. Sewage outlet; 17. Filter wheel; 18. Dust cover; 19. Rotating shaft; 20. Bearing. Detailed Implementation

[0046] like Figures 1-2 As shown, a tanning apparatus for vegetable-tanned cowhide fittings includes a material tank 1, a processing chamber 4, a wastewater tank 5, a leather area conveying system, a leather soaking treatment system, a wastewater purification system, and an exhaust treatment system.

[0047] The material tank 1 is located on the outside of the treatment chamber 4, and the wastewater tank 5 is located inside the treatment chamber 4.

[0048] The leather area conveying system includes a conveyor frame. One end of the conveyor frame passes through a through hole on one side of the processing chamber 4 and is placed next to the material trough 1. The conveyor frame is positioned above the wastewater trough 5. Several conveyor shafts 2 and conveyor belts 3 surrounding the conveyor shafts 2 are connected to the conveyor frame. The conveyor belts 3 have a mesh structure. A liquid collection tank for collecting dripping liquid is provided below the conveyor belts 3. The liquid collection tank is connected to the wastewater trough 5.

[0049] The leather soaking treatment system is located on one side of the treatment chamber 4. The leather soaking treatment system includes a circulation pump 6 installed on one side of the treatment chamber 4. The circulation pump 6 is a high-pressure pump. Its outlet pipe is also equipped with a chemical additive mechanism for injecting chemical materials into the water flow in proportion. The circulation pump 6 is connected to the outlet pipe of the sewage purification system through the purified water inlet 8. A purified water pipe 7 is connected to the outlet end of the circulation pump 6. The purified water pipe 7 is located above the conveyor belt 3 and fixed on the inner top surface of the treatment chamber 4. Several nozzles 10 are installed on the purified water pipe 7. The nozzles 10 are high-pressure rotary nozzles.

[0050] The sewage tank 5 is provided with a sewage purification port 9, and a water inlet pipe of the sewage purification system is connected with the sewage tank 5 through the sewage purification port 9. The sewage purification system comprises a filter box and a filter wheel 17 arranged in the filter box. The filter wheel 17 is rotatably connected in the filter box through a rotating shaft 19 and a bearing 20. The filter box is provided with a purified water outlet 14, a sewage inlet 15 and a sewage outlet 16. The filter box is connected with the purified water inlet 8 of the circulating pump 6 through the purified water outlet 14. The filter box is connected with the sewage purification port 9 through the sewage inlet 15. The filter box is further provided with a dust cover 18, which covers the periphery of the filter wheel 17, so as to block external dust and keep the filter wheel 17 clean, thereby ensuring the stable operation and safe operation of the sewage purification system and the whole tanning device.

[0051] The exhaust treatment system is installed on the other side of the treatment chamber 4. The exhaust treatment system comprises an exhaust hood 11, a fan 12 and an exhaust pipe 13. The exhaust hood 11 is arranged at the inner top end of the treatment chamber 4. The exhaust hood 11 is connected with one end of the exhaust pipe 13 through an exhaust gas purification mechanism. The other end of the exhaust pipe 13 is connected with the air inlet of the fan 12.

[0052] Embodiment one

[0053] As shown in the accompanying drawings, Figure 3 a tanning process of a full-plant tanning cowhide harness leather tanning device, comprising the following steps:

[0054] A. Pretreatment of rawhide:

[0055] 1. Rawhide cutting: cutting from the tail root along the ridge for 100 cm, and cutting vertically to the ridge for 120 cm. According to the different textures of rawhide, heavy or light tanning products are selected;

[0056] 2. Immersion treatment: pre-immersion temperature is 18-25℃, and 1.5 times of clean water and 8% of immersion aid (ZL300 and D117 each account for 50%, i.e. 4%) are added. The rawhide is continuously rotated for 60 minutes until the water absorption is restored to the fresh skin state;

[0057] 3. Fleshing and unhairing: a hydraulic fleshing machine with an automatic thickness adjustment range of 10 mm is used at a speed of 19-50 m / min to apply a constant pressure (25 MPa) to the conveying belt during fleshing, so as to uniformly polish the immersed skin and remove the flesh membrane. Then, the rawhide is placed in a 5% enzyme-containing neutral solution (2% protease, 1% lipase, 1.5% ammonium sulfate and 0.5% non-ionic surfactant) and rotated for 120 minutes. After fleshing and unhairing, the rawhide is placed flat in a cool place for 10 hours;

[0058] 4. Static liming: under the condition of 30℃ and liquid ratio of 2.5, 1% liming aid (1% sodium sulfide and sodium hydroxide mixed alkali) is added continuously for 30 minutes, 3% lime is added after mixing evenly for 120 minutes, it is stopped for 60 minutes, it is continuously rotated for 60 minutes, it is stopped for 60 minutes, it is rotated for 10 minutes every hour, and it is stopped overnight to complete liming; the down hair condition is checked in real time during the static liming process, and the rotation speed and rotation time are effectively and timely adjusted;

[0059] 5. Slice skin deliming: a slice skin machine is used, and the slice skin thickness is adjusted according to the requirements; the slice skin is evenly divided into the required thickness; the slice skin is placed in a solution containing 5% ammonium chloride or ammonium sulfate and rotated to delime, and the water is changed every 30 minutes to wash the residual reagent.

[0060] B. Acid soaking and pre-tanning: the raw hide after the pre-treatment is placed in clean water, and first to fourth pre-tanning chemicals (1% sodium hexametaphosphate as a water softener, 0.5% solid composite lubricant composed of high molecular wax, aluminum stearate and calcium stearate as an anti-twist agent, 4% dispersed tannin and 4% phenol tannin) are added in sequence and continuously rotated for 120 minutes (after adding each pre-tanning chemical, it is continuously rotated for 30 minutes); the acid soaking and pre-tanning process has a recovery liquid collection and filtration device, and the liquid is circulated by a spraying machine. According to the detection of the effective components of the residual liquid after the acid soaking and pre-tanning, the amount of the liquid is controllably added, so that the circulating liquid can be used for the pre-tanning and tanning of the subsequent leather.

[0061] C. Vegetable tanning: at 25-35℃, the leather to be treated is conveyed into the treatment chamber of the leather soaking treatment system through the trough 1 and the leather area conveying system, the circulating pump 6 is started, and the first vegetable tanning chemical is added through the chemical adding mechanism. The purified water from the sewage purification system is mixed with the chemical material, and then sprayed into the inside of the leather through the high-pressure nozzle 10. The spraying time is 30 minutes. The waste water generated during the treatment process enters the sewage purification system for purification treatment through the sewage inlet. The purified water is circulated back to the inlet of the circulating pump. The waste gas generated during the treatment process is collected and discharged by the exhaust treatment system, and then the above-mentioned actions are repeated. The second vegetable tanning chemical, the third vegetable tanning chemical and the fourth vegetable tanning chemical are added respectively to treat the leather.

[0062] D. Intermediate treatment: the leather embryo after vegetable tanning is taken out from the drum, and is treated for 120 minutes to remove the excess water on the surface. Then, the leather embryo after the static treatment is squeezed to squeeze out the excess internal water, so as to prepare for the subsequent deep processing.

[0063] E. Retanning and rinsing: Put the rawhide after vegetable tanning into the drum, then add 2% dispersed tannin, 2% composite sulfone tanning agent (aromatic sulfone bridge tanning agent, aromatic sulfone amphoteric tanning agent) at room temperature, and then fill 2% melamine as a filler, and rotate for 240 minutes (the rotation time after each step is 80 minutes). The device has a liquid recovery and dosing filter, and the liquid is circulated by a spraying machine. Then, put the rawhide in water at 45°C with a liquid ratio of 0.8, and add 3% maleic anhydride acid additive and 1% formic acid acid additive successively, and rotate for 60 minutes and 30 minutes respectively. After sufficient acid treatment, add 1% ciartan multifunctional additive for pH adjustment and surface activation, and remove the residual tanning agent, grease and impurities of the rawhide by washing;

[0064] F. Oil addition and acid fixation: Put the rawhide after retanning into the drum, add 3% light-resistant oil, 3% modified beef tallow, 2% sulfurized fish oil, and 2% composite oil agent composed of penetration oil and 1% imazalil to ensure uniform penetration of the oil into the fibers, and treat for 180 minutes at an internal temperature of 45°C and a liquid ratio of 0.3. The acid fixation process is based on a fixed time interval (30 minutes) to add 0.1% formic acid to the drum in five times, and the temperature and pH value of the solution are kept stable at a liquid ratio of 1, to realize the synergistic optimization of oil fixation and pH adjustment of the rawhide. The solution temperature is kept at 45°C, and the pH value is kept stable at 3.5-3.8;

[0065] G. Hanging and stretching: The hanging and stretching process specifically includes horseback riding, standing, water squeezing, hanging, drying, stretching, softening, rolling, and storage;

[0066] Horseback riding: After oil addition and acid fixation, the rawhide is taken out of the drum and the flesh side is stacked on the opposite side;

[0067] Standing: Stand at room temperature for 3-5 days to evenly distribute water and oil;

[0068] Water squeezing: Use a hydraulic water squeezing machine to remove excess water to a moisture content of 45%-50% at a pressure of 0.3-0.5 MPa, to prepare for drying;

[0069] Hanging: Hang the water-squeezed rawhide on a drying rack in a ventilated environment at 28-30°C for 4 hours;

[0070] Drying: After ventilated hanging, the rawhide is heated to 40-45°C and dried to a moisture content of 18%-22%;

[0071] Stretching: Use a rotary drum stretcher to stretch the rawhide to make the surface flat and smooth, and eliminate wrinkles;

[0072] Softening: Soften the fibers by high-frequency vibration to give the leather a soft feel;

[0073] Rolling: on the rolling machine, the pressure is 1.0-1.2 MPa, so that the crust is compacted, the grain surface is flat, and the wear resistance and gloss are improved;

[0074] Storage: after the moisture content meets the standard, the flat stacked products are stored in a dry and ventilated environment.

[0075] Example Two

[0076] As shown in Figure 3 , a tanning process of a tanning device for full-vegetable tanned harness leather includes the following steps:

[0077] A full-vegetable tanned harness leather tanning process and device includes the following steps:

[0078] A, pretreatment of rawhide:

[0079] 1. Rawhide cutting: cutting from the tail root along the ridge 100 cm, perpendicular to the ridge 120 cm, according to the different texture of rawhide, selecting heavy or light leather tanning products;

[0080] 2. Immersion treatment: pre-immersion temperature 18-25℃, add 1.5 times the amount of water, 8% immersion aid (D117, TJ-A160 each accounts for 50%, i.e. 4%), continue to rotate for 60 minutes until the rawhide is restored to the fresh state;

[0081] 3. Fleshing and unhairing: using a hydraulic fleshing machine with an automatic thickness adjustment range of 10 mm at a speed of 19-50 m / min to apply a constant pressure (25 MPa) to the conveyor belt during fleshing, so as to evenly polish the immersed skin and remove the flesh membrane, then placing it in a 5% enzyme-containing neutral solution (2% protease, 1% lipase, 1.5% ammonium sulfate and 0.5% non-ionic surfactant) and rotating for 120 minutes, after dehumidification, the skin is completely dehaired and laid flat in a cool place for 10 hours;

[0082] 4. Static liming: under the condition of 30℃ and liquid ratio of 2.5, add 1% liming aid (1% sodium sulfide and sodium hydroxide mixed lye) continuously for 30 minutes, add 3% lime after mixing evenly, continue to rotate for 120 minutes, stop for 60 minutes, continue to rotate for 60 minutes, stop for 60 minutes, and rotate for 10 minutes every hour, stop overnight, complete liming; check the unhairing situation in real time during static liming, and adjust the rotation speed and time effectively and timely;

[0083] 5. Piece skin deliming: using a piece skin machine, adjusting the thickness of the piece skin according to the demand, evenly dividing the skin into the required thickness; placing the piece skin in a solution containing 5% ammonium chloride or ammonium sulfate for deliming, continuously rotating for 120 minutes and changing water every 30 minutes to wash away the residual reagent.

[0084] B, pickling pre-tanning: the pre-treated raw hide is placed in clean water, and the first to fourth pre-tanning chemicals (sodium pyrophosphate as a water softener 1%, Seta_SLP as an anti-winding agent 0.5%, dispersed tannin 4% and phenolic tannin 4%) are added in sequence and continuously rotated for 120 minutes (30 minutes of continuous rotation after each addition of pre-tanning chemicals); the pickling pre-tanning process has a recovery liquid collection and filtration device, and the liquid circulation is carried out by a spraying machine. According to the effective component detection of the residual liquid after pickling pre-tanning, the amount of liquid is controllably added, so as to ensure that the circulating liquid can be used for subsequent pre-tanning and tanning of the leather.

[0085] C, tanning with plant tanning agent: at 25-35°C, the leather to be treated is transported into the treatment chamber of the leather soaking treatment system through the tank 1 and the leather area conveying system, the circulating pump 6 is started, and the first tanning with plant tanning agent chemical is added through the chemical adding mechanism. The purified water from the sewage purification system is mixed with the chemical material, and then sprayed into the inside of the leather through the nozzle 10 by high pressure. The spraying time is 30 minutes. The waste water generated during the treatment process enters the sewage purification system for purification treatment through the sewage inlet. The purified water is circulated back to the inlet of the circulating pump. The waste gas generated during the treatment process is collected and discharged by the exhaust treatment system, and then the above-mentioned actions are repeated. The second tanning with plant tanning agent chemical, the third tanning with plant tanning agent chemical and the fourth tanning with plant tanning agent chemical are added respectively to treat the leather;

[0086] D, intermediate treatment: the leather embryo after tanning with plant tanning agent is taken out from the drum and is subjected to static treatment for 120 minutes to remove the excess surface water. Subsequently, the water-extracted leather embryo is subjected to water-extraction operation to squeeze out the excess internal water for subsequent deep processing.

[0087] E, re-tanning and rinsing: the leather embryo after tanning with plant tanning agent is placed in the drum, and then 2% dispersed tannin, 2% composite sulfone tanning agent (aromatic sulfone amphoteric tanning agent, yellowing-resistant sulfone tannin tanning agent), and 2% melamine as a filler are added in sequence at room temperature, and the drum is rotated for 240 minutes (the rotation time after each addition of chemicals is 80 minutes). The system has a recovery liquid collection and chemical addition filtration device, and the liquid circulation is carried out by a spraying machine. Subsequently, the leather embryo is placed in clean water at 45°C and with a liquid ratio of 0.8, 3% maleic anhydride acid additive is added, and the drum is continuously rotated for 60 minutes. 1% formic acid acid additive is added, and the drum is continuously rotated for 30 minutes. After sufficient acid treatment, 1% ciartan multifunctional additive is added for pH adjustment and surface activation, and the residual tanning agent, grease and impurities of the leather embryo are removed by water washing;

[0088] F. Oil and solid acid: After retanning, the leather blank is placed in a rotating drum, and 3% light-resistant oil, 3% modified beef tallow, 2% sulfurized fish oil, and 2% penetrating oil are added to the composite oil agent, and 1% imazalil is added to ensure uniform penetration of the oil into the fibers, and the treatment time is 180 minutes; the solid acid process is based on a fixed time interval (30 minutes) to add 0.1% formic acid to the rotating drum 5 times, and the temperature and pH value of the solution are maintained stable under the condition of liquid ratio of 1, to realize the synergistic optimization of oil fixation and pH adjustment of the leather blank. The solution temperature is maintained at 45°C, and the pH value is stabilized at 3.5-3.8;

[0089] G. Hanging and stretching: the hanging and stretching process specifically includes horseback, standing, water squeezing, hanging, drying, stretching, softening, rolling, and storage;

[0090] Horseback: after oil and solid acid, the leather embryo is placed on the horseback with the flesh side facing up;

[0091] Standing: standing at room temperature for 3-5 days to evenly distribute water and oil;

[0092] Water squeezing: using a hydraulic water squeezing machine, the pressure is 0.3-0.5 MPa, and the water content is removed to 45%-50% to prepare for drying;

[0093] Hanging: the leather embryo after water squeezing is hung on the drying rack, and first hung in a ventilated environment at 28-30°C for 4 hours;

[0094] Drying: the leather embryo after ventilation and hanging is heated to 40-45°C, and continues to dry until the water content is 18%-22%;

[0095] Stretching: using a rotating drum stretcher to stretch, making the leather embryo surface flat and grain smooth, and eliminating wrinkles;

[0096] Softening: through high-frequency vibration of the softening machine, the fibers are loosened, and the leather is given a soft touch;

[0097] Rolling: on a rolling machine, the pressure is 1.0-1.2 MPa, making the leather embryo compact and the grain flat, improving wear resistance and gloss;

[0098] Storage: after detection of water content, the leather is flatly stacked and stored in a dry and ventilated environment.

[0099] The present application adopts the steps of raw hide pretreatment, pickling pre-tanning, vegetable tanning, intermediate treatment, re-tanning and rinsing, oil filling and acid fixing, and hanging and airing stretching, etc., to obtain a full-vegetable tanned cowhide harness leather product. In the raw hide pretreatment process, ciartan multifunctional additives, degreasing agents, water soaking enzyme preparations, and sodium chloride are added to make the raw hide fibers absorb water to restore the fresh hide state. The addition of enzyme-containing neutral solution promotes the shedding of fine hair on the surface of the raw hide and improves the surface treatment activity. Liming treatment can further effectively remove hair, epidermis, grease and interstitial substance between fibers, and make the raw hide further expand, keep the fibers loose, increase the interstitial space between fibers, and thus provide a basis for improving the penetration speed of soft water agent, anti-twist agent, dispersed tannin and phenolic tannin in the subsequent pickling pre-tanning process, and shorten the overall time cycle of vegetable tanning.

[0100] The use of soft water agent in the pickling pre-tanning process can effectively remove calcium and magnesium ions in water, prevent them from reacting with chemicals, improve the softness of the leather, reduce the residual ash, and the anti-twist agent can effectively reduce the friction of the leather, prevent it from being twisted and torn, and avoid uneven dyeing. The dispersed tannin can disperse the vegetable tanning agent, promote its uniform penetration, and keep the leather surface fine. The phenolic tannin can cross-link with collagen, giving the leather softness, durability, water resistance, wear resistance, and dark appearance.

[0101] In the vegetable tanning process, various tannins in tannin contain abundant tannins, which can cross-link with collagen fibers to give the leather basic tanning effect and improve water resistance and wear resistance. Different tannins can be matched to adjust the color and body of the leather to meet the appearance and texture requirements of the harness leather. The use of dispersed tannin can effectively disperse tannin, prevent it from depositing on the leather surface, promote uniform penetration of tannin, and avoid color spots and cracks on the leather surface. At the same time, it can assist the subsequent material absorption to ensure the uniformity of the overall tanning of the leather. The use of phenolic tannin can enhance the tanning effect, deeply combine with collagen, further improve the tightness and durability of the leather, deepen the color of the leather, give the harness leather a stable color tone, and optimize the fineness of the leather surface. Light oil resistance can effectively improve the light resistance and overall quality of the leather. In the re-tanning and rinsing process, the use of dispersant can promote the rapid and uniform penetration of tannin, prevent excessive deposition on the leather surface, and avoid color spots and cracks. The re-tanning agent can further improve the performance of the leather, such as tensile strength, fullness, softness, etc., and can also change the surface charge of the leather, which is beneficial to uniform dyeing. The filler can effectively fill the interstitial space of the leather fibers, improve the fullness, elasticity and tightness, and reduce the part difference. Acidic additives can adjust the pH value to provide a suitable environment for the re-tanning reaction, and can also help remove impurities in the leather. The weak alkaline performance of ciartan multifunctional additives gently removes acid, stabilizes the fiber structure, improves the fullness and hand feeling of the leather, disperses lime, reduces growth marks, and makes the grain surface smoother and more uniform.

[0102] The use of light-resistant oil in the oiling and solid acid process can improve the light resistance of leather, slow down the discoloration and aging caused by light, and at the same time form a protective film on the leather surface, which can help to enhance the waterproofness and wear resistance, improve the gloss and hand feeling of the leather surface; modified tallow gives the leather a soft and full hand feeling, improves the elasticity and moisturizing degree of the leather, enhances the low-temperature stability of the leather, reduces the risk of cracking during use, and meets the demand of cowhide leather for texture; sulfurized fish oil has the functions of fatliquoring and lubrication, penetrates into the fiber gap, improves the softness and extensibility of the leather, and also helps to disperse other oils, enhancing the uniformity of fatliquoring; penetrating oil can reduce the surface tension of oil, promote the penetration of light-resistant oil and modified tallow into the fiber layer of leather, avoid the oil only adhering to the surface, and ensure the uniformity and durability of fatliquoring effect; imazalil can inhibit the growth of mold, prevent the leather from being easily moldy due to the presence of moisture and oil after oiling and solid acid, and prolong the storage and use cycle of cowhide leather products; formic acid can adjust the pH of the system to be acidic, fix the combination of oil and leather fiber, prevent oil migration, and at the same time neutralize residual alkaline substances to stabilize the performance of the leather.

[0103] The following table is a comparison table of original process consumption and present process consumption:

[0104]

[0105] The above-described embodiments are only descriptions of preferred modes of the present application and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A tanning apparatus for tanning full-plant tanned harness leather, characterized in that: It comprises a tank (1), a processing chamber (4), a wastewater tank (5), a leather area conveying system, a leather soaking treatment system, a sewage purification system and an exhaust treatment system; The tank (1) is arranged outside the processing chamber (4), and the wastewater tank (5) is arranged inside the processing chamber (4); The leather area conveying system comprises a conveying frame, one end of the conveying frame penetrates through a through hole arranged on one side of the processing chamber (4) and is then arranged beside the tank (1), the conveying frame is arranged above the wastewater tank (5), and a plurality of conveying shafts (2) and a conveying belt (3) surrounding the conveying shafts (2) are connected to the conveying frame; The leather soaking treatment system is arranged on one side of the processing chamber (4), the leather soaking treatment system comprises a circulating pump (6) arranged on one side of the processing chamber (4), the circulating pump (6) is a high-pressure pump, a chemical material injection mechanism for injecting chemical materials into water flow in proportion is further arranged in an outlet pipeline of the circulating pump (6), the circulating pump (6) is connected to a water outlet pipeline of the sewage purification system through a purified water inlet (8), a purified water pipeline (7) is connected to one end of the water outlet of the circulating pump (6), the purified water pipeline (7) is arranged above the conveying belt (3) and is fixed to an inner top surface of the processing chamber (4), a plurality of nozzles (10) are arranged on the purified water pipeline (7), and the nozzles (10) are high-pressure rotary nozzles; The wastewater tank (5) is provided with a sewage purification opening (9), and a water inlet pipeline of the sewage purification system is connected to the wastewater tank (5) through the sewage purification opening (9); The exhaust treatment system is arranged on the other side of the processing chamber (4).

2. The tanning apparatus for tanning full vegetable tanned leather harness leather according to claim 1, characterized in that: The conveying belt (3) has a mesh structure, and a liquid collecting tank for collecting dripping liquid is arranged below the conveying belt (3), and the liquid collecting tank is communicated with the wastewater tank (5).

3. The tanning apparatus for tanning full vegetable tanned leather harness leather according to claim 1, characterized in that: The sewage purification system comprises a filter box and a filter wheel (17) arranged in the filter box, the filter wheel (17) is rotatably connected to the filter box through a rotating shaft (19) and a bearing (20), the filter box is provided with a purified water outlet (14), a sewage inlet (15) and a sewage discharge opening (16), the filter box is connected to the purified water inlet (8) of the circulating pump (6) through the purified water outlet (14), the filter box is connected to the sewage purification opening (9) through the sewage inlet (15), and a dust cover (18) is further arranged in the filter box and covers an outer periphery of the filter wheel (17).

4. The tanning apparatus for tanning full vegetable tanned leather harness leather according to claim 1, characterized in that: The exhaust treatment system comprises an exhaust hood (11), a fan (12) and an exhaust pipeline (13), the exhaust hood (11) is arranged at an inner top end of the processing chamber (4), the exhaust hood (11) and one end of the exhaust pipeline (13) are connected through an exhaust gas purification mechanism, and the other end of the exhaust pipeline (13) is connected to an air inlet of the fan (12).

5. A tanning process for the tanning apparatus of full vegetable tanned leather harnesses according to any of claims 1-4, characterized by, The method comprises the following steps: A, the pre-treatment of raw hide: the raw hide is placed in a rotating drum, water and soaking aids are added, and rotation is continued until the water absorption recovers to the fresh hide state; the flesh side of the soaked hide is polished to remove the flesh membrane, and then placed in an enzyme-containing neutral solution for rotation and hair removal, and then placed in a cool place for flat laying and standing; lime soaking aids and lime are added in turn and continuous rotation is performed to complete lime soaking; A piece of leather machine is used to adjust the thickness of the leather piece according to the requirements, and the leather piece is uniformly divided into the required thickness; the leather piece after slicing is placed in a solution containing ammonium chloride and ammonium sulfate and rotated to remove lime, and then washed with clean water to remove the remaining lime; B, acid pickling and pre-tanning: the pre-treated raw hide is placed in water, and first to fourth pre-tanning chemicals are added in turn and continuously rotated; the acid pickling and pre-tanning process has a recovery liquid collection and filtration device, and the liquid is circulated by a spraying machine; C, tannage by tanning agent implantation: the leather to be treated is conveyed into the treatment chamber of the leather soaking treatment system through the trough (1) and the leather area conveying system, the circulating pump (6) is started, and the first tanning agent implantation chemical is added through the chemical adding mechanism, the purified water from the sewage purification system is mixed with the chemical material, and then sprayed into the leather through the high-pressure nozzle (10), the spraying time is 30 minutes, the waste water generated in the process is introduced into the sewage purification system for purification treatment, the purified water is circulated back to the inlet of the circulating pump, the waste gas generated in the process is collected and discharged by the exhaust treatment system, and then the above actions are repeated, the second, third and fourth tanning agent implantation chemicals are added respectively to treat the leather; D, intermediate treatment: the leather embryo after tannage by tanning agent implantation is taken out from the rotating drum, and is subjected to standing treatment for 120 minutes to remove the excess water on the surface, and then the standing leather embryo is subjected to water squeezing operation to squeeze out the excess internal water, so as to prepare for subsequent deep processing; E, retanning and rinsing: the retanning process is to place the leather blank treated by tannage by tanning agent implantation into a rotating drum, and then add dispersing agent, retanning agent and filling agent, and rotate, which has a recovery liquid collection and filtration device, and the liquid is circulated by a spraying machine. The rinsing process is to add acid additives and multifunctional additives to adjust the pH value and activate the surface, and then remove the residual tanning agent, grease and impurities on the leather blank by water washing; F, oiling and acid fixing: the oiling process is to place the leather blank treated by retanning into a rotating drum, add water, composite oil agent and mildew-proof agent to ensure uniform penetration of the oil into the leather fibers; the acid fixing process is to add formic acid into the rotating drum in multiple times based on fixed time intervals, maintain the temperature and pH value of the solution stable, and realize the synergistic optimization of oil fixing and pH adjustment of the leather blank; G, hanging and stretching: after the oiling and acid fixing, the leather embryo is taken out from the drum, and the flesh side of the leather embryo is relatively overlapped and stacked; Standing: standing at room temperature for 3-5 days to make the water and oil evenly distributed; Water squeezing: hydraulic water squeezing machine is used for treatment, the pressure is 0.3-0.5 MPa, and the excess water is removed to a water content of 45%-50% for preparation for drying; Hanging: the leather embryo treated by water squeezing is hung on a hanging rack, and is hung in a ventilated environment at 28-30℃ for 4 hours; Drying: the leather embryo after ventilated hanging is heated to 40-45℃, and is continuously dried until the water content is 18%-22%. Stretching: stretched by rotary drum stretching machine to make the surface of the leather flat and smooth, and to eliminate wrinkles; Softening: loosened by high-frequency vibration of the softening machine to give the leather soft touch; Rolling: performed on the rolling machine with pressure of 1.0-1.2 MPa to make the leather compact and the grain flat, and to improve wear resistance and gloss; Storage: after the detection of water content, the leather is stored in a well-ventilated and dry environment; The hanging and stretching process specifically includes the first day: temperature 25 ℃, humidity 70-80%; the second day: temperature 30 ℃, humidity 60-70%; the third day: temperature 35 ℃, humidity 40-50%.

6. Tannage process of full-vegetable tanned leather for harnesses according to claim 5, characterized by the fact that: The soaking auxiliary agent in the raw hide pretreatment process includes 1% ciartan multifunctional auxiliary agent, 1% degreasing agent, 2% soaking enzyme preparation and 4% sodium chloride, the 1% degreasing agent is any two of ZL300, D117 and TJ-A160, the enzyme-containing neutral solution used includes 2% protease, 1% lipase, 1.5% ammonium sulfate and 0.5% non-ionic surfactant, and the liming auxiliary agent used includes 1% sodium sulfide and sodium hydroxide mixed lye.

7. The tanning process of full-vegetable tanned leather for harnesses according to claim 5, characterized by the fact that: The first to fourth pre-tanning agents in the pickling pre-tanning process include 1% water softener, 0.5% anti-twist agent, 4% dispersed tannin and 4% phenolic tannin, the 1% water softener includes sodium hexametaphosphate and sodium pyrophosphate, the 0.5% anti-twist agent includes a solid composite lubricant composed of high molecular wax, aluminum stearate and calcium stearate and Seta_SLP.

8. The tanning process of full-vegetable tanned leather for harnesses according to claim 5, characterized by the fact that: The first plant tanning agent in the plant tanning process includes 50% multi-type vegetable tannin, the 50% multi-type vegetable tannin is any two of gallic tannin, quercetin tannin and flavonoid tannin, the second plant tanning agent includes 1% light-resistant oil, the 1% light-resistant oil includes nitrocellulose water-based emulsion light oil and water-based polyurethane light-resistant oil, the third plant tanning agent includes 2% dispersed tannin, and the fourth plant tanning agent includes 5% phenolic tannin.

9. The tanning process of full-vegetable tanned leather for harnesses according to claim 5, characterized by the fact that: The dispersing agent in the retanning and rinsing process is 2% dispersed tannin, the retanning agent is 2% composite sulfone tanning agent, the 2% composite sulfone tanning agent is any two of aryl sulfone bridge tanning agent, aryl sulfone amphoteric tanning agent and yellowing-resistant sulfone tannin tanning agent, and the filler is 2% melamine; the acid auxiliary agent is 1% formic acid and 3% maleic anhydride, and the multifunctional auxiliary agent is 1% ciartan multifunctional auxiliary agent.

10. The tanning process of full-vegetable tanned leather for harnesses according to claim 5, characterized by the fact that: The composite oil agent in the oiling and acid fixing process is 3% light-resistant oil, 3% modified beef tallow, 2% sulfided fish oil and 2% penetrating oil; the mildew-proof agent is 1% prochloraz; the amount of formic acid used in the acid fixing process is 0.1% at a time, the number of times is 5, and the pH value is stabilized at 3.5-3.8.

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