Tanning method of crocodile skin

Abstract

The invention relates to the technical field of leather processing, and discloses a crocodile skin tanning method which comprises the following steps: step 1, draining pickled crocodile skin; secondly, the crocodile skin is toggled, the crocodile skin needs to be fully toggled, the periphery of the skin is fixed to a toggling plate, the area of the crocodile skin is maximized, the toggling plate is preferably provided with a porous or net-shaped structure, and after the crocodile skin is fixed to the toggling plate, tanning liquid can penetrate through the porous or net-shaped structure to make contact with the skin; thirdly, the toggling plate and the crocodile skin are jointly immersed into a container containing tanning agent operation liquid, all the toggling plate and the crocodile skin are required to be immersed into the tanning agent operation liquid, and ultrasonic stirring or mechanical stirring is started. According to the tanning method of the crocodile skin, in the tanning process of the crocodile skin, the combination of a tanning agent and skin fibers has the trend that the skin shrinks, after tanning is finished, the skin and a toggling plate are taken out of a container, standing and aging are conducted for 48 hours or longer, in the standing and aging process, the tanning agent continues to react with the skin fibers, and the tanning agent and the skin fibers are tanned; therefore, the effect of improving the area yield of the crocodile skin can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field, in particular to a tanning method for crocodile leather. Background Art

[0002] Crocodile leather has become an important part of the leather industry. As a high-end specialty leather, it has formed a complete industrial structure of design, development and production, attracting the attention of many consumers. In China, crocodile farming has gradually prospered, and large-scale breeding of Nile crocodiles, saltwater crocodiles, Siamese crocodiles and American alligators has been successfully bred. There is also a sufficient source of crocodile raw leather. However, there are very few independently developed crocodile leather processing technologies that can be used in actual production. This has greatly restricted the growth and development of the specialty leather processing industry.

[0003] Like other leather products, crocodile leather is sold by area. In order to obtain a larger area, on the one hand, the fibers of the crocodile leather need to be loosened appropriately, such as by using alkali treatment, enzyme treatment and other methods to loosen the crocodile leather fibers to obtain a larger area; on the other hand, the crocodile leather must be prevented from shrinking during the tanning process, because tanning is a cross-linking process that will cause the leather to shrink. Conventional tanning is carried out in a drum or groove, and the crocodile leather is in a non-fixed free state. After the leather shrinks, the area will decrease, resulting in a decrease in the added value of the product.

[0004] Chrome tanning is a widely used process in leather production because the leather obtained by chrome tanning is soft, plump and easy to process later. However, the area shrinkage rate of the chrome tanning method is relatively large. For ordinary leather products with relatively low price per unit area, the area shrinkage is acceptable, but for crocodile leather, the price per unit area is relatively high. Therefore, how to solve the problem of area shrinkage in the tanning process, especially the chrome tanning process, has always plagued the crocodile leather industry. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies of the prior art, the present invention provides a tanning method for crocodile leather, which can improve the area yield of crocodile leather and solve the problems of the above-mentioned technology.

[0007] Technical Solution

[0008] To achieve the above object, the present invention provides the following technical solution: a tanning method for crocodile leather, comprising the following steps:

[0009] Step 1: After acid soaking, drain the crocodile skin;

[0010] Step 2: stretch the crocodile skin on a board, which is required to be fully stretched and fixed on the board around the skin to maximize its area. The board preferably has a porous or mesh structure so that after the crocodile skin is fixed on the board, the tanning liquid can pass through the porous or mesh structure and contact the skin;

[0011] Step 3: Immerse the stretch board and the crocodile skin together in a container containing a tanning agent operating liquid, and make sure that they are completely immersed in the tanning agent operating liquid. Start ultrasonic stirring or mechanical stirring, and the crocodile skin will complete the tanning process in a fixed state.

[0012] Step 4: Take the stretch board and crocodile skin out of the container, cover them with plastic sheeting, and let them stand for more than 48 hours;

[0013] Step 5: Remove the crocodile skin from the stretcher and proceed with other normal operations.

[0014] Preferably, the stretching board and the leather are immersed in a container filled with chrome tanning liquid, and the leather is required to be completely immersed in the chrome tanning liquid. The pH value of the chrome tanning liquid is between 2-2.5, the sodium chloride concentration is 40-80g / l, and the chromium content (equivalent to Cr2O3) is 2-10g / l. Ultrasonic stirring or mechanical stirring is started, and the treatment is carried out at room temperature for 16-24 hours.

[0015] Preferably, sodium bicarbonate solution is slowly added to the container to uniformly increase the pH value of the chrome tanning solution to about 3.8-4.2 within 4-8 hours, and then the temperature is increased to 38-42° C. and the reaction is continued by heat preservation for 18-24 hours.

[0016] Preferably, the stretching board and the leather are immersed in a container containing tannin solution, and the whole of the leather is required to be immersed in the tannin solution. The pH value of the vegetable tanning solution is controlled to be 5.8, 35°C, and the tannin concentration is 15g / l. Ultrasonic stirring or mechanical stirring is started, and the treatment is carried out for 24 hours.

[0017] Preferably, acetic acid solution is slowly added to the container to uniformly increase the pH value of the chrome tanning solution to 4 within 4 hours, and the reaction is continued by heat preservation for 36 hours.

[0018] Preferably, the above method is suitable for all tanning methods, including but not limited to: chrome tanning, aldehyde tanning, vegetable tanning, aluminum tanning, organophosphorus tanning, etc. The specific operation can be adjusted according to the requirements of the specific tanning method.

[0019] Compared with the prior art, the present invention provides a tanning method for crocodile leather, which has the following beneficial effects:

[0020] According to the tanning method for crocodile leather, during the tanning process of the crocodile leather, the combination of the tanning agent and the leather fiber will cause the leather to shrink, but since the crocodile leather is fixed on the stretching board, it will not shrink due to the tanning effect. After the tanning is completed, the leather and the stretching board are taken out of the container and left to age for more than 48 hours. During the standing and aging process, the tanning agent continues to react with the leather fiber, thereby achieving the effect of increasing the area yield of the crocodile leather. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not 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.

[0022] Embodiment 1: Alligator leather tanning method using chrome tanning process

[0023] A tanning method for crocodile leather comprises the following steps:

[0024] (1) After pickling, drain the crocodile skin;

[0025] (2) stretching the crocodile skin on a board, which is required to be fully stretched and fixed on the board on all sides to maximize its area. The board preferably has a porous or mesh structure so that after the crocodile skin is fixed on the board, the tanning liquid can pass through the porous or mesh structure and contact the skin;

[0026] (3) Immerse the stretch board and the leather together in a container filled with chrome tanning liquid, requiring that the leather is completely immersed in the chrome tanning liquid. The pH value of the chrome tanning liquid is controlled to be 2.1, the sodium chloride concentration is 50 g / l, and the chromium content (equivalent to Cr2O3) is 3 g / l. Start ultrasonic stirring or mechanical stirring and treat at room temperature for 16 hours;

[0027] (4) slowly adding sodium bicarbonate solution into the container to uniformly increase the pH value of the chrome tanning solution to about 4.2 within 4 hours, then raising the temperature to 42° C. and continuing to keep the temperature for 24 hours;

[0028] (5) Take the stretch board and crocodile skin out of the container, cover them with plastic sheeting, and let them stand for more than 48 hours;

[0029] (6) Remove the crocodile skin from the stretcher and carry out other normal operations.

[0030] Embodiment 2: Alligator leather tanning method using chrome tanning process

[0031] A tanning method for crocodile leather comprises the following steps:

[0032] (1) After pickling, drain the crocodile skin;

[0033] (2) stretching the crocodile skin on a board, which is required to be fully stretched and fixed on the board on all sides to maximize its area. The board preferably has a porous or mesh structure so that after the crocodile skin is fixed on the board, the tanning liquid can pass through the porous or mesh structure and contact the skin;

[0034] (3) Immerse the stretch board and the leather together in a container filled with chrome tanning liquid, requiring that they are completely immersed in the chrome tanning liquid. The pH value of the chrome tanning liquid is controlled to be 2.4, the sodium chloride concentration is 70 g / l, and the chromium content (equivalent to Cr2O3) is 8 g / l. Start ultrasonic stirring or mechanical stirring and treat at room temperature for 24 hours;

[0035] (4) slowly adding sodium bicarbonate solution into the container to uniformly increase the pH value of the chrome tanning solution to about 3.9 within 8 hours, then raising the temperature to 38° C. and continuing the reaction at this temperature for 18 hours;

[0036] (5) Take the stretch board and crocodile skin out of the container, cover them with plastic sheeting, and let them stand for more than 48 hours;

[0037] (6) Remove the crocodile skin from the stretcher and carry out other normal operations.

[0038] Example 3: Crocodile leather tanning process using vegetable tanning

[0039] A tanning method for crocodile leather comprises the following steps:

[0040] (1) After pickling, drain the crocodile skin;

[0041] (2) stretching the crocodile skin on a board, which is required to be fully stretched and fixed on the board on all sides to maximize its area. The board preferably has a porous or mesh structure so that after the crocodile skin is fixed on the board, the tanning liquid can pass through the porous or mesh structure and contact the skin;

[0042] (3) Immerse the stretch board and the leather together in a container containing tannin solution, requiring that they are completely immersed in the tannin solution. The pH value of the vegetable tanning solution is controlled to be 5.8, 35°C, and the tannin concentration is 15g / l. Start ultrasonic stirring or mechanical stirring and treat for 24 hours.

[0043] (4) slowly adding acetic acid solution into the container to uniformly increase the pH value of the chrome tanning solution to 4 within 4 hours, and continue to keep the temperature for 36 hours;

[0044] (5) Take the stretch board and crocodile skin out of the container, cover them with plastic sheeting, and let them stand for more than 48 hours;

[0045] (6) Remove the crocodile skin from the stretcher, rinse it, and proceed with other normal operations.

[0046] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for tanning crocodile skin, Features: The following steps are involved: Step 1: After acid soaking, drain the crocodile skin; Step 2: stretch the crocodile skin on a board, which is required to be fully stretched and fixed on the board around the skin to maximize its area. The board preferably has a porous or mesh structure so that after the crocodile skin is fixed on the board, the tanning liquid can pass through the porous or mesh structure and contact the skin; Step 3: Immerse the stretch board and the crocodile skin together in a container containing a tanning agent operating liquid, and make sure that they are completely immersed in the tanning agent operating liquid. Start ultrasonic stirring or mechanical stirring, and the crocodile skin will complete the tanning process in a fixed state. Step 4: Take the stretch board and crocodile skin out of the container, cover them with plastic sheeting, and let them stand for more than 48 hours; Step 5: Remove the crocodile skin from the stretcher and proceed with other normal operations.

2. A method for tanning crocodile leather according to claim 1, Features: Immerse the stretching board and the leather together in a container filled with chrome tanning liquid. The pH value of the chrome tanning liquid is between 2-2.5, the sodium chloride concentration is 40-80g / l, and the chromium content (equivalent to Cr2O3) is 2-10g / l. Start ultrasonic or mechanical stirring and treat at room temperature for 16-24 hours.

3. A method for tanning crocodile skin according to claim 1, Features: Slowly add sodium bicarbonate solution into the container to evenly increase the pH value of the chrome tanning solution to about 3.8-4.2 within 4-8 hours, then increase the temperature to 38-42°C and continue to keep the reaction warm for 18-24 hours.

4. A method for tanning crocodile leather according to claim 1, Features: Immerse the stretch board and the leather together in a container filled with tannin solution. Make sure they are completely immersed in the tannin solution. Control the pH value of the vegetable tanning solution to 5.8, 35°C, and the tannin concentration to 15g / l. Start ultrasonic or mechanical stirring and treat for 24 hours.

5. The tanning method of crocodile leather according to claim 1, Features: Slowly add acetic acid solution into the container to evenly increase the pH value of the chrome tanning solution to 4 within 4 hours, and continue to keep the reaction warm for 36 hours.

6. A method for tanning crocodile leather according to claim 1, Features: The above method is suitable for all tanning methods, including but not limited to: chrome tanning, aldehyde tanning, vegetable tanning, aluminum tanning, organic phosphorus tanning, etc. The specific operation can be adjusted according to the requirements of the specific tanning method.