A method and apparatus for dehairing leather using enzyme preparations.

Abstract

The present invention provides a processing method for leather depilation using an enzyme preparation, comprising the following steps: filling animal skin with water to a fresh skin state, and then removing dirt and subcutaneous tissue on the surface; after transferring the animal skin to a processing device, first adding water of 80-150% of the skin weight, and then adding a depilatory agent for depilatory treatment for 3-6 hours, until most of the hair is removed cleanly; adding an ashless expansion agent for alkali expansion until depilation is completed; after depilation is completed, conventional liming, deliming, softening, pickling, and tanning processes are performed. The present invention uses an immobilized enzyme to replace traditional free enzymes in the leather depilation step, and the immobilized enzyme has the characteristics of slow release. Compared with traditional free state depilatory enzyme preparations, the immobilized enzyme can be slowly released when in contact with the surface of the animal skin, avoiding damage to the surface of the animal skin caused by too fast early reaction, and the operation of pre-treatment of the animal skin is not required in the early stage.

Description

[Technical field]

[0001] The invention relates to the field of leather processing, and in particular to a leather depilatory processing method and a processing device utilizing an enzyme preparation. [Background technology]

[0002] my country is a major leather processing country in the world, and its processing and export volumes have long ranked first in the world. Therefore, the leather industry has become a light industry with rapid technological progress and development in the national economy, and is closely related to the national living standards and quality.

[0003] Traditional leather crafts include soaking, dehairing, liming, deliming, softening, pickling, tanning and other processes. Enzyme preparations are usually used in soaking, dehairing and softening to accelerate the dehairing and softening. At present, the existing dehairing enzyme preparations are not only complex in composition, but also difficult to control in dosage. If the dosage is not appropriate, it will react too quickly with the surface of animal fur and cause damage to the fur surface. For example, the prior art CN104711379B discloses an enzymatic dehairing method for eliminating grain damage of cowhide leather. In order to significantly improve the dehairing efficiency and shorten the enzymatic dehairing treatment time, the dehairing enzyme preparation used includes any one of Bacillus subtilis AS1.398 neutral protease, Actinomycetes 166 neutral protease, Bacillus pumilus 209 alkaline protease or DTM198 protease; the dehairing enzyme preparation of the prior art has a very high dehairing efficiency in the early stage of the dehairing step, but the dehairing speed in the early stage is too fast, which can easily cause irreversible damage to the leather surface, so a collagenase inhibitor needs to be added in the early stage for pretreatment to prevent leather damage; however, the efficiency of the enzyme preparation will decrease in the later stage of dehairing, so the overall dehairing time is not shortened; in addition, the dehairing enzyme preparation cannot be recycled and is not conducive to environmental protection.

[0004] In view of this, the inventor of this case conducted in-depth research on the above-mentioned issues, which led to the emergence of this case. [Summary of the invention]

[0005] The present invention aims to solve the technical problem that the existing depilatory enzyme preparation has too fast initial depilatory speed, causing irreversible damage to the leather surface and cannot be recycled, and provides a leather depilatory processing method and processing device that can slowly release the depilatory enzyme preparation and recycle the depilatory enzyme preparation.

[0006] The present invention is achieved in that a method for depilating leather using an enzyme preparation comprises the following steps:

[0007] (1) Fill the animal skin with water until it is in a fresh state, and then remove the dirt and subcutaneous tissue on the surface;

[0008] (2) After transferring the animal skin to the processing device, first add 80-150% of the skin weight of water, then add the depilatory agent to carry out the depilation treatment for 3-6 hours until most of the hair is removed;

[0009] (3) adding an ashless expander for alkali expansion until the depilation is completed;

[0010] (4) After the unhairing is completed, the conventional liming, deliming, bating, pickling and tanning processes are carried out.

[0011] Furthermore, in step (2), the depilatory agent comprises 20-50% by weight of water, 0.2-0.6% of a surfactant, and 0.3-0.6% of a depilatory enzyme preparation.

[0012] Furthermore, in step (2), the depilatory enzyme preparation is an immobilized enzyme.

[0013] Furthermore, the immobilized enzyme is sodium alginate immobilized protease.

[0014] Furthermore, the preparation process of the sodium alginate immobilized protease is as follows:

[0015] Step 1: Weigh 1-2g of sodium alginate and dissolve it in water to prepare a sodium alginate aqueous solution, the concentration of the sodium alginate aqueous solution is 1-3%;

[0016] Step 2: Prepare a protease aqueous solution with a phosphate buffer solution of pH 6-8 and protease; the activity of the protease is 120 IU-300 IU;

[0017] Step 3: Mix the sodium alginate aqueous solution and the protease aqueous solution, add 0.05-0.1 g of pentasodium phosphate and 0.1-0.2 g of polyethylene glycol, and stir well to obtain a sodium alginate protease aqueous solution;

[0018] Step 4: Use a syringe to add the sodium alginate protease aqueous solution dropwise into a 0.01-0.16 mol / L sterile calcium chloride solution, take it out after solidification for 20-50 minutes, wash it with deionized water for 3 times, and dry it at 50°C to obtain granular sodium alginate immobilized protease.

[0019] Furthermore, in step 1, the concentration of the sodium alginate aqueous solution is 2%.

[0020] Furthermore, in step three, the dosage ratio of sodium alginate to protease is 1 (g):210 (IU).

[0021] Furthermore, in step 4, the curing time is 35 minutes.

[0022] Furthermore, in step 4, the concentration of the sterile calcium chloride solution is 0.05 mol / L.

[0023] On the other hand, a processing device for leather depilatory processing method using enzyme preparations includes a processing mechanism for preliminary processing of animal skins, a liquid supply mechanism for conveying depilatory reagents to the processing mechanism, a solution recovery mechanism for recovering the depilatory reagents, and a fur collecting mechanism for collecting fur; the output end of the liquid supply mechanism is connected to the input end of the processing mechanism, the input end of the fur collecting mechanism is located at the output end of the processing mechanism, and the input end of the solution recovery mechanism is connected to the output end of the processing mechanism.

[0024] The advantages of the present invention are:

[0025] 1. The present invention uses an immobilized enzyme to replace the traditional free enzyme in the leather depilation step. The immobilized enzyme has the characteristic of slow release. Compared with the traditional free depilatory enzyme preparation, the immobilized enzyme can be slowly released when in contact with the surface of animal skin, avoiding damage to the surface of animal skin caused by too fast reaction in the early stage, and no pretreatment of animal skin is required in the early stage. The immobilized enzyme not only has the characteristics of maintaining high efficiency and specificity and mildness of enzyme catalysis, but also can improve the thermal stability and chemical stability of the enzyme; and after the depilatory reagent made of the immobilized enzyme is used, the immobilized enzyme can be separated from other chemical components by simple methods such as centrifugation and filtration, which is conducive to repeated use of the immobilized enzyme and purification of the product, thereby saving processing costs.

[0026] 2. The immobilized enzyme is specifically sodium alginate immobilized protease. The sodium alginate immobilized protease uses sodium alginate as a carrier and not only has the advantages of good thermal stability, but also has a long retention time of enzyme activity under high temperature. Moreover, the preparation process of the sodium alginate immobilized protease is simple, the reaction conditions are mild, and the operation is convenient, which is conducive to production. Equal amounts of sodium alginate immobilized protease and conventional enzyme preparations are kept at the same temperature for 2 hours, and finally it is found that the activity loss of the sodium alginate immobilized protease is small, which shows that the sodium alginate immobilized protease has good thermal stability; therefore, the present invention uses sodium alginate immobilized protease as a depilatory enzyme preparation to maintain the depilatory efficiency without damaging the animal skin.

[0027] 3. Polyethylene glycol and pentasodium phosphate are added in the process of combining sodium alginate as a carrier with protease. Polyethylene glycol and pentasodium phosphate are stable in nature, will not react with sodium alginate aqueous solution and protease aqueous solution, and can greatly improve the adsorption rate of sodium alginate to protease. At the same time, since the granular sodium alginate immobilized protease of the present invention is a mixture containing pentasodium phosphate, after being made into a depilatory agent, the pentasodium phosphate dispersed in the solution can also play a role in pre-tanning and shortening the curing time, and can better protect the leather grain surface in the later stage.

[0028] 4. In the present invention, a depilatory agent is used to depilate animal skin in a processing mechanism. When the processing mechanism is working, the depilatory enzyme preparation contacts the animal skin, and the sodium alginate immobilized protease in the depilatory agent is slowly released to avoid the depilation speed being too fast. After the depilation is completed, the processing mechanism separates the depilatory agent from the animal skin to recycle the depilatory agent, which not only saves production costs but also avoids waste of resources.

Brief Description of the Drawings

[0029] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0030] Figure 1 It is a schematic diagram of the structure of the processing device in the present invention.

[0031] Figure 2 It is a structural schematic diagram of the gathering component in the present invention.

[0032] Processing device 100, processing mechanism 1, frame 11, support seat 12, frame cover 13, fur output port 14, first liquid inlet 15, first liquid outlet 16, liquid supply mechanism 2, second liquid inlet 21, second liquid outlet 22, liquid pump 23, solution recovery mechanism 3, fur collecting mechanism 4, roller 41, rotating cylinder 5, first driving mechanism 51, movable rod 52, filtering assembly 6, spoiler mechanism 7, second driving mechanism 71, stirring blade 72, fur cleaning mechanism 8, gathering assembly 81, push plate 811, first bend 812, second bend 813, fur gathering cavity 814, fur gathering port 815, liquid discharge port 816, third driving mechanism 82. [Specific implementation method]

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] Embodiment 1

[0035] This embodiment provides a method for leather depilation using an enzyme preparation, which specifically comprises the following steps:

[0036] (1) Fill the animal skin with water until it is in a fresh state, and then remove the dirt and subcutaneous tissue on the surface.

[0037] (2) After the animal skin is transferred to the processing device, water of 80-150% of the skin weight is first added, and then a depilatory agent is added to carry out depilation for 3-6 hours until most of the hair is removed.

[0038] (3) Add ash-free expander for alkali expansion until the depilation is completed.

[0039] (4) After the unhairing is completed, the conventional liming, deliming, bating, pickling and tanning processes are carried out.

[0040] In this embodiment, in step (2), the hair removal treatment time is 4 hours.

[0041] In this embodiment, in step (2), the depilatory agent comprises 20-50% by weight of water, 0.2-0.6% of a surfactant, and 0.3-0.6% of a depilatory enzyme preparation.

[0042] In this embodiment, in step (2), the depilatory agent comprises 40% by weight of water, 0.5% of a surfactant, and 0.5% of a depilatory enzyme preparation.

[0043] In this embodiment, in step (2), the depilatory enzyme preparation is an immobilized enzyme. The immobilized enzyme has the characteristic of slow release. Compared with the traditional free depilatory enzyme preparation, the present invention uses the immobilized enzyme instead of the free enzyme in the leather depilatory process. The immobilized enzyme can be slowly released and contact with the surface of the animal skin, avoiding the reaction too fast to damage the surface of the animal skin. The traditional leather depilatory process needs to add collagen inhibitors in the early stage of depilation to prevent animal skin damage. Therefore, when the immobilized enzyme is used instead of the free enzyme, it is not necessary to perform pretreatment in the early stage while avoiding animal skin damage, thereby optimizing the depilatory process; and it can also reduce the excessive residue of chemical substances on the leather surface, and the leather obtained is greener and safer. The immobilized enzyme not only has the characteristics of maintaining the high efficiency and specificity of enzyme catalysis, but also improves the thermal stability and chemical stability of the enzyme; and after the depilatory reagent made of the immobilized enzyme is used, the immobilized enzyme can be separated from other chemical components by simple methods such as centrifugation and filtration, which is conducive to the repeated use of the immobilized enzyme and the purification of the product, thereby saving processing costs.

[0044] In the present embodiment, the immobilized enzyme is sodium alginate immobilized protease. Sodium alginate immobilized protease not only has the advantage of good thermal stability with sodium alginate as a carrier, but also has a long retention time of enzyme activity under high temperature, and the preparation process of sodium alginate immobilized protease is simple, the reaction conditions are mild, and the operation is convenient, which is conducive to production. Equal amounts of sodium alginate immobilized protease and conventional enzyme preparations are incubated at the same temperature for 2h, and finally it is found that the activity loss of sodium alginate immobilized protease is small, which shows that sodium alginate immobilized protease has good thermal stability. Therefore, the present invention uses sodium alginate immobilized protease as a depilatory enzyme preparation to maintain depilatory efficiency without damaging animal skin.

[0045] The following further illustrates the beneficial effects of the leather depilatory processing method using the present embodiment through several experimental groups and comparative groups. Specifically, 10 kg of animal skin is used as the raw material, 100% of the weight of the skin is firstly added with water, and then various depilatory reagents with different component contents are added for testing, and the damage on the surface of the animal skin is detected after the depilatory is completed.

[0046] Experimental Group 1

[0047] The processing method of leather depilation in this experimental group is as follows:

[0048] 10 kg of animal skins are filled with water to a fresh state, and then surface dirt and subcutaneous tissue are removed; after the animal skins are transferred to a processing device, 100% of the skin weight of water is added, and then a depilatory reagent containing 20% ​​of the skin weight of water, 0.2% of a surfactant, and 0.3% of a depilatory enzyme preparation is added to carry out depilation for 3 hours until most of the hair is removed and the surface damage of the animal skin is detected.

[0049] Experimental Group 2

[0050] The processing method of leather depilation in this experimental group is as follows:

[0051] 10 kg of animal skins are filled with water to a fresh state, and then surface dirt and subcutaneous tissue are removed; after the animal skins are transferred to a processing device, 100% of the skin weight of water is added, and then a depilatory reagent containing 20% ​​of the skin weight of water, 0.3% of a surfactant, and 0.4% of a depilatory enzyme preparation is added to carry out depilation for 3 hours until most of the hair is removed and the surface damage of the animal skin is detected.

[0052] Experimental Group 3

[0053] The processing method of leather depilation in this experimental group is as follows:

[0054] 10 kg of animal skins are filled with water to a fresh state, and then surface dirt and subcutaneous tissue are removed; after the animal skins are transferred to a processing device, 100% of the skin weight of water is added, and then a depilatory reagent containing 30% of the skin weight of water, 0.4% of a surfactant, and 0.45% of a depilatory enzyme preparation is added to carry out depilation treatment for 4 hours until most of the hair is removed and the surface damage of the animal skin is detected.

[0055] Experimental Group 4

[0056] The processing method of leather depilation in this experimental group is as follows:

[0057] 10 kg of animal skins are filled with water to a fresh state, and then surface dirt and subcutaneous tissue are removed; after the animal skins are transferred to a processing device, 100% of the skin weight of water is added, and then a depilatory reagent containing 40% of the skin weight of water, 0.5% of a surfactant, and 0.5% of a depilatory enzyme preparation is added to carry out depilation treatment for 5 hours until most of the hair is removed and the surface damage of the animal skin is detected.

[0058] Experimental Group 5

[0059] The processing method of leather depilation in this experimental group is as follows:

[0060] 10 kg of animal skins are filled with water to a fresh state, and then surface dirt and subcutaneous tissue are removed; after the animal skins are transferred to a processing device, 100% of the skin weight of water is added, and then a depilatory reagent containing 50% of the skin weight of water, 0.6% of a surfactant, and 0.6% of a depilatory enzyme preparation is added to carry out depilation treatment for 6 hours until most of the hair is removed and the surface damage of the animal skin is detected.

[0061] Comparison Group 1

[0062] The processing method of leather depilation in this experimental group is as follows:

[0063] 10 kg of animal skins are filled with water to a fresh state, and then surface dirt and subcutaneous tissue are removed; after the animal skins are transferred to a processing device, 100% of the skin weight of water is added, and then a depilatory reagent containing 50% of the skin weight of water, 0.6% of a surfactant, and 1.0% of a depilatory enzyme preparation is added to carry out depilation treatment for 6 hours until most of the hair is removed and the surface damage of the animal skin is detected.

[0064] Comparison Group 2

[0065] The processing method of leather depilation in this experimental group is as follows:

[0066] 10 kg of animal skins are filled with water to a fresh state, and then surface dirt and subcutaneous tissue are removed; after the animal skins are transferred to a processing device, 100% of the skin weight of water is added, and then a depilatory reagent containing 50% of the skin weight of water, 0.6% of a surfactant, and 1.1% of a depilatory enzyme preparation is added to carry out depilation treatment for 6 hours until most of the hair is removed and the surface damage of the animal skin is detected.

[0067] Comparison group 3

[0068] The processing method of leather depilation in this experimental group is as follows:

[0069] 10 kg of animal skins are filled with water to a fresh state, and then surface dirt and subcutaneous tissue are removed; after the animal skins are transferred to a processing device, 100% of the skin weight of water is added, and then a depilatory reagent containing 50% of the skin weight of water, 0.6% of a surfactant, and 1.2% of a depilatory enzyme preparation is added to carry out depilation treatment for 6 hours until most of the hair is removed and the surface damage of the animal skin is detected.

[0070] Comparison Group 4

[0071] 10 kg of animal skins are filled with water to a fresh state, and then surface dirt and subcutaneous tissue are removed; after the animal skins are transferred to a processing device, 100% of the skin weight of water is added, and then a depilatory reagent containing 50% of the skin weight of water, 0.6% of a surfactant, and 0.5% of free protease is added to carry out depilation for 6 hours until most of the hair is removed and the surface damage of the animal skin is detected.

[0072] According to the experimental results of the above five experimental groups and three comparison groups, the detection of skin damage is as follows:

[0073] Table 1 Relevant data of each experimental group and comparison group

[0074]

[0075] It can be seen from Table 1 that, under the premise of omitting the preliminary pretreatment process, the five experimental groups used the depilatory reagent of the present invention to depilate the animal skin, and after the depilation was completed, the surface of the animal skin would not be damaged. According to the detection results of the five experimental groups and the four comparative groups, when the depilatory enzyme preparation exceeded 1.0%, the surface of the animal skin was slightly damaged; from the experimental results of experimental group four and comparative group four, it can be seen that under the same conditions, the conventional free protease was used instead of the sodium alginate immobilized protease of this embodiment, and the leather grain surface was seriously damaged. It can be seen that the present invention uses immobilized protease as a depilatory enzyme preparation to maintain the depilatory efficiency without damaging the animal skin.

[0076] Embodiment 2

[0077] This embodiment provides a preparation process of sodium alginate immobilized protease, and the specific steps are as follows:

[0078] Step 1: Weigh 1-2 g of sodium alginate and dissolve it in 30-200 mL of water to prepare a sodium alginate aqueous solution; the concentration of the sodium alginate aqueous solution is 1-3%.

[0079] Step 2: Prepare a protease aqueous solution with a phosphate buffer solution of pH 6-8 and protease, wherein the amount of protease is 150 IU-300 IU.

[0080] Step 3: Mix the sodium alginate aqueous solution and the protease aqueous solution, add 0.05-0.1 g of pentasodium phosphate and 0.1-0.2 g of polyethylene glycol, and stir well to obtain the sodium alginate protease aqueous solution.

[0081] Step 4: Use a syringe to add the sodium alginate protease aqueous solution dropwise into a 0.01-0.16 mol / L sterile calcium chloride solution, take it out after solidification for 30-60 minutes, wash it with deionized water for 3 times, and dry it at 50°C to obtain granular sodium alginate immobilized protease.

[0082] The preparation process of the sodium alginate immobilized protease of the present embodiment can not only obtain the sodium alginate immobilized protease with high enzyme activity, but also the process is simple, easy to operate, and the conversion rate of the sodium alginate immobilized protease is high. In step 3, polyethylene glycol and pentasodium phosphate are added in the process of sodium alginate as a carrier combined with the protease, and polyethylene glycol and pentasodium phosphate are stable in nature, not only will not react with the sodium alginate aqueous solution and the protease aqueous solution, but also can significantly improve the adsorption rate of sodium alginate to the protease. At the same time, because the granular sodium alginate immobilized protease of the present invention is a mixture, which contains pentasodium phosphate, after the depilatory reagent is made, the pentasodium phosphate is dispersed in the solution and can also play the role of pre-tanning and shortening the curing time, and the leather grain surface can be protected from being damaged in the later stage.

[0083] In step 3 of this embodiment, the optimal ratio of sodium alginate to protease is 1 (g): 210 (IU). Next, 1g of sodium alginate is dissolved in water to prepare a sodium alginate aqueous solution with a concentration of 1%, and experiments are conducted with different amounts of protease to measure the activity of sodium alginate adsorbing protease (i.e., the carrier carrying capacity), and the following data are obtained:

[0084] Table 2: Effect of the ratio of sodium alginate to protease on protease immobilization

[0085] Sodium alginate(g) 1 1 1 1 1 1 1 Protease (IU) 120 150 180 210 240 270 300 Carrier loading capacity (IU / g) 16.2 24.5 41.3 51.5 48.3 38.4 29.6

[0086] It can be seen from Table 2 that when the dosage ratio of sodium alginate to protease is 1 (g): 210 (IU), the activity of the immobilized protease reaches the maximum value. With the increase of the enzyme dosage, the activity of the protease adsorbed by sodium alginate (i.e., the carrier loading capacity) shows a trend of first increasing and then decreasing. When the dosage of the enzyme preparation increases to 210 IU / g, the carrier loading capacity reaches the maximum value of 51.5 IU / g.

[0087] In step 3 of the present invention, the concentration of the sodium alginate aqueous solution is 2%. The following experiment was conducted with different concentrations of sodium alginate and a protease with an activity of 210 IU, and the dosage ratio of sodium alginate to protease was 1 (g): 210 (IU) to measure the activity of protease adsorbed by sodium alginate (i.e., the carrier carrying capacity), and the following data were obtained:

[0088] Table 3: Effect of sodium alginate concentration on protease immobilization

[0089] Sodium alginate concentration (%) 0.5 1.0 1.5 2 2.5 3 3.5 Carrier loading capacity (IU / g) 29.2 36.1 42.3 53.2 39.3 26.4 20.4

[0090] It can be seen from Table 3 that when the sodium alginate concentration reaches 2%, the activity of the protease (i.e., the carrier carrying capacity) reaches the maximum value, and then gradually decreases. Therefore, the optimal concentration of the sodium alginate carrier is 2%. The concentration of sodium alginate can significantly affect the activity of the immobilized protease. When sodium alginate reacts with calcium ions in a sterile calcium chloride solution to form particles, the density of the particles increases with the increase in the sodium alginate concentration, and the corresponding particle pore size becomes smaller; when the sodium alginate concentration is low, the particle pore size is large, and the enzyme molecules in the particles are easily lost, so the enzyme activity is low; when the sodium alginate concentration is too high, the particle pore size is too small, so the enzyme activity decreases. Therefore, the concentration of the sodium alginate carrier should be controlled within an appropriate range.

[0091] In step 4 of this embodiment, the solidification time is 45 minutes. Next, the same sodium alginate protease aqueous solution was added dropwise to the sterile calcium chloride solution and then allowed to stand for different solidification times to measure the activity of sodium alginate adsorbed protease (i.e., the carrier carrying capacity), and the following data were obtained:

[0092] Table 4: Effect of immobilization time on protease immobilization

[0093] Fixation time (min) 20 25 30 35 40 45 50 Carrier loading capacity (IU / g) 51.2 52.1 56.0 57.0 51.3 44.6 38.7

[0094] It can be seen from Table 4 that 35 minutes is the best solidification time. Too long or too short a solidification time will reduce the activity of sodium alginate immobilized protease. This is because as time goes by, the solidification becomes more and more complete, and the protease is more firmly adsorbed in the calcium alginate particles and is not easy to fall off. However, when the time continues to extend, the effect of calcium ions on the immobilized protease intensifies, causing the protease activity to decrease.

[0095] In step 4 of this embodiment, the concentration of the sterile calcium chloride solution is 0.05 mol / L. Next, the same sodium alginate protease aqueous solution was added dropwise to sterile calcium chloride solutions of different concentrations for solidification for 35 minutes to measure the activity of sodium alginate adsorbed protease (i.e., carrier loading capacity), and the following data were obtained:

[0096] Table 5: Effect of sterile calcium chloride solution on protease immobilization

[0097]

[0098] It can be seen from Table 5 that with the increase of the concentration of sterile calcium chloride solution, the activity of the protease first rises rapidly. When the concentration of sterile calcium chloride solution reaches 0.05 mol / L, the activity of the protease is the highest, and then it shows a slow downward trend. Because when the concentration of calcium chloride is too low, the calcium alginate particles are not fully solidified, the protease is not completely adsorbed, and it is easy to lose; when the concentration of calcium chloride is too high, calcium ions will react with the protease, causing the protease activity to decrease. Therefore, the optimal concentration of calcium chloride during immobilization is 0.05 mol / L.

[0099] Embodiment 3

[0100] See also Figure 1 to Figure 2 As shown, this embodiment provides a processing device 100 for depilating leather using an enzyme preparation, including a processing mechanism 1 for pre-processing animal skins, a liquid supply mechanism 2 for conveying a depilatory agent to the processing mechanism 1, a solution recovery mechanism 3 for recovering the depilatory agent, and a fur collecting mechanism 4 for collecting fur; the output end of the liquid supply mechanism 2 is connected to the input end of the processing mechanism 1, the input end of the fur collecting mechanism 4 is located at the output end of the processing mechanism 1, and the input end of the solution recovery mechanism 3 is connected to the output end of the processing mechanism 1. In the processing device 100 of the present invention, a depilatory agent is used to depilate the animal skin in the processing mechanism 1. When the processing mechanism 1 is working, the depilatory enzyme preparation contacts the animal skin, and the sodium alginate immobilized protease in the depilatory agent is slowly released to avoid too fast a depilation speed; after the depilation is completed, the processing mechanism 1 separates the depilatory agent from the animal fur to recycle the depilatory agent to avoid wasting resources.

[0101] Working principle: water with 80-150% of the skin weight and washed animal skin are placed into the processing mechanism 1, and the liquid supply mechanism 2 transports the pre-configured depilatory agent to the processing mechanism 1 to depilate the animal skin for 3-6 hours until most of the hair is removed; then, an ash-free expander is added for alkaline expansion until the depilation is completed; after the depilation is completed, the solution recovery mechanism 3 recovers the depilatory agent discharged from the processing mechanism 1, and the fur collection mechanism 4 collects the fur discharged from the processing mechanism 1.

[0102] In this embodiment, the processing mechanism 1 includes a frame 11, a support seat 12 for supporting the frame 11, a frame cover 13 rotatably mounted on the upper end of the frame 11, a rotating cylinder 5 rotatably mounted inside the frame 11, a first driving mechanism 51 for driving the rotating cylinder 5 to rotate, and a filter assembly 6 assembled inside the frame 11 and located below the rotating cylinder 5; the driving shaft of the first driving mechanism 51 passes through the rotating cylinder 5 and connects the rotating cylinder 5 to the frame 11. During operation, the rotating cylinder 5 is continuously rotated under the drive of the first driving mechanism 51, so that the animal skin in the cylinder is fully in contact with the depilatory agent.

[0103] In this embodiment, two groups of movable rods 52 are provided in the inner cavity of the rotating cylinder 5, and the animal skin is located between the movable rods 52 and the cylinder wall of the rotating cylinder 5 or between the two groups of movable rods 52. As the rotating cylinder 5 rotates, the animal skin contacts the outer wall of the movable rods 52 in the rotating cylinder 5 through the flexible mechanical action of the movable rods 52, and the movable rods 52 continuously make the sodium alginate immobilized protease contact the animal skin to perform a depilatory reaction.

[0104] In this embodiment, the first driving mechanism 51 is preferably a driving motor.

[0105] In this embodiment, the flow disturbance mechanism 7 and the second driving mechanism 71 for driving the flow disturbance mechanism 7 to rotate are also included. The flow disturbance mechanism 7 is installed at the central position of the bottom of the frame 11 and is located below the filter assembly 6. The second driving mechanism 71 is arranged at the bottom outside the frame 11. Since the sodium alginate immobilized protease is a granular material, it is easy to be deposited at the bottom of the inner cavity of the frame 11. By installing the flow disturbance mechanism 7 at the central position of the bottom of the frame 11, the depilatory reagent at the bottom of the frame 11 can be disturbed so as to continuously push the granular sodium alginate immobilized protease upward, so that the animal skin and the effective ingredients in the depilatory reagent can be more fully and evenly contacted, which is beneficial to depilation.

[0106] In this embodiment, in order to further reduce the deposition probability of the granular sodium alginate immobilized protease, the flow disturbance mechanism 7 includes a plurality of stirring blades 72 arranged vertically, and the radius of the stirring blade 72 located at the bottom is greater than the radius of the stirring blade 72 located at the top.

[0107] In this embodiment, the second driving mechanism 71 is preferably a driving motor.

[0108] In this embodiment, the filter assembly 6 is a filter screen, and the mesh number of the filter screen is 50-200. The filter screen is a detachable filter screen, and since the fineness of different animal furs is different, it can be adaptively replaced to improve the applicability of the processing device.

[0109] In this embodiment, a fur cleaning mechanism 8 is also included above the filter assembly 6; the fur cleaning mechanism 8 includes a gathering assembly 81 and a third driving mechanism 82 that drives the gathering assembly 81 to push the fur to the fur outlet 14; both sides of the gathering assembly 81 are in contact with the inner wall of the frame 11 to prevent the fur from overflowing. When the hair removal is completed, the hair removal reagent and fur inside the frame 11 are stationary, and the fur is deposited above the filter net. At this time, the third driving mechanism 82 drives the gathering assembly 81 to move along the surface of the filter net to push the fur to the fur outlet 14. The gathering component 81 can not only squeeze out the depilatory agent between the furs, but also slowly gather the furs, and finally squeeze and limit all the furs at the fur outlet 14, so as to prevent the depilatory agent from flowing downwards and the furs from being scattered again when the depilatory agent is recovered. When the depilatory agent is recovered, the fur outlet 14 is opened, and the third driving mechanism 82 pushes the gathering component 81 out of the frame 11, so that all the furs fall into the fur collecting mechanism 4.

[0110] In this embodiment, the gathering component 81 includes a push plate 811 with an inclined angle, a first bent portion 812 and a second bent portion 813 for gathering fur, the bottom surface of the push plate 811 is tightly fitted with the filter net, the upper end of the push plate 811 is connected to one end of the first bent portion 812, and the other end of the first bent portion 812 is connected to one end of the second bent portion 813, the push plate 811, the first bent portion 812 and the second bent portion 813 are surrounded by a fur gathering cavity 814, and a fur gathering mouth 815 is formed between one end of the push plate 811 and the other end of the second bent portion 813; the second bent portion 813 includes a first end connected to the first bent portion 812, and a second end forming the fur gathering mouth 815 with the push plate 811, and the second bent portion 813 is inclined downward from the first end to the second end. By setting the second curved portion 813 to be inclined downward from the first end to the second end, when the gathering component 81 is pushed, on the one hand, the fur and the depilatory agent slowly enter the fur gathering cavity 814 from the fur gathering opening 815, and on the other hand, the depilatory agent flows upward along the upper surface of the second curved portion 813, which can reduce the pushing resistance. At the same time, under the action of water pressure, the second curved portion 813 slowly bends, and the fur gathering opening 815 slowly becomes smaller, preventing the fur from running out when the fur gathering cavity 814 is disturbed and surging. By setting the push plate 811 to have an inclined angle, the fur enters the fur gathering cavity 814 along the inclined surface of the push plate 811 during the pushing process of the push plate 811, thereby improving the gathering efficiency of the fur.

[0111] In this embodiment, the second curved portion 813 is made of an elastic material. By setting the second curved portion 813 to be made of an elastic material, when the gathering component 81 is pushed, the second curved portion 813 can bend downward under the action of water pressure, so that the fur gathering opening 815 gradually becomes smaller, thereby preventing the fur from running out when the fur gathering cavity 814 is disturbed and surging.

[0112] In this embodiment, a plurality of drainage ports 816 are formed through the first curved portion 812. By providing a plurality of drainage ports 816, when the gathering component 81 is pushed, the hair removal agent can be discharged from the drainage ports 816, so as to avoid that the fur gathering chamber 814 is not sufficient to accommodate the fur and the hair removal agent, and the probability of the fur violently surging and running out in the fur gathering chamber 814 can be reduced, so as to further improve the gathering efficiency of the fur.

[0113] In this embodiment, in order to allow the hair removal agent to be discharged smoothly from the discharge port 816 , a plurality of the discharge ports 816 are distributed in a matrix on the first curved portion 812 .

[0114] In this embodiment, the third driving mechanism 82 is a driving cylinder.

[0115] In this embodiment, a roller 41 is provided at the bottom end of the fur collecting mechanism 4 to facilitate the transfer of the fully collected fur.

[0116] In this embodiment, a first liquid inlet 15 is formed on the upper side surface of the frame 11, and a first liquid outlet 16 is formed at the bottom end of the frame 11; a second liquid outlet 22 is formed on one side of the liquid supply mechanism 2, and a second liquid inlet 21 is provided on the top of the liquid supply mechanism 2; the frame 11 is connected to the solution recovery mechanism 3 through the first liquid inlet 15.

[0117] In this embodiment, a liquid pump 23 is further provided between the processing mechanism 1 and the liquid supply mechanism 2 .

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for depilating leather using an enzyme preparation, characterized in that: The steps include: (1) Fill the animal skin with water until it is in a fresh state, and then remove the dirt and subcutaneous tissue on the surface; (2) After transferring the animal skin to the processing device, first add 80-150% of the skin weight of water, and then add a depilatory agent to carry out depilatory treatment for 3-6 hours until most of the hair is removed; the depilatory agent contains 20-50% of the skin weight of water, 0.2-0.6% of a surfactant, and 0.3-0.6% of a depilatory enzyme preparation, and the depilatory enzyme preparation is a sodium alginate immobilized protease; (3) adding an ashless expander for alkali expansion until the depilation is completed; (4) After the unhairing is completed, the conventional liming, deliming, bating, pickling and tanning processes are carried out.

2. The method for depilating leather using an enzyme preparation as claimed in claim 1, wherein: The preparation process of the sodium alginate immobilized protease is as follows: Step 1: Weigh 1-2g of sodium alginate and dissolve it in water to prepare a sodium alginate aqueous solution, the concentration of the sodium alginate aqueous solution is 1-3%; Step 2: Prepare a protease aqueous solution with a phosphate buffer solution of pH 6-8 and protease; the activity of the protease is 120 IU-300 IU; Step 3: Mix the sodium alginate aqueous solution and the protease aqueous solution, add 0.05-0.1 g of pentasodium phosphate and 0.1-0.2 g of polyethylene glycol, and stir well to obtain a sodium alginate protease aqueous solution; Step 4: Use a syringe to add the sodium alginate protease aqueous solution dropwise into a 0.01-0.16 mol / L sterile calcium chloride solution, take it out after solidification for 20-50 minutes, wash it with deionized water for 3 times, and dry it at 50°C to obtain granular sodium alginate immobilized protease.

3. The method for depilating leather using an enzyme preparation as claimed in claim 2, wherein: In step 1, the concentration of the sodium alginate aqueous solution is 2%.

4. The method for depilating leather using an enzyme preparation as claimed in claim 2, wherein: In step three, the dosage ratio of sodium alginate to protease is 1 (g):210 (IU).

5. The method for depilating leather using an enzyme preparation as claimed in claim 2, wherein: In step 4, the curing time is 35 minutes.

6. The method for depilating leather using an enzyme preparation as claimed in claim 2, wherein: In step 4, the concentration of the sterile calcium chloride solution is 0.05 mol / L.

7. A processing device for leather depilation using an enzyme preparation as claimed in any one of claims 1 to 6, characterized in that: It includes a processing mechanism for performing preliminary processing on animal skins, a liquid supply mechanism for conveying depilatory reagents to the processing mechanism, a solution recovery mechanism for recovering the depilatory reagents, and a fur collecting mechanism for collecting fur; the output end of the liquid supply mechanism is connected to the input end of the processing mechanism, the input end of the fur collecting mechanism is located at the output end of the processing mechanism, and the input end of the solution recovery mechanism is connected to the output end of the processing mechanism.

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