Crocodile skin desquamation method

Abstract

The invention relates to the technical field of leather processing, and discloses a crocodile skin desquamation method which comprises the following steps: step 1, preparing raw materials: soaking and degreasing crocodile skin, and taking the crocodile skin as a weighing basis; 2, pretreatment: treating 300% of water, 1% of a penetrant and 2-4% of an alkali expansion inhibitor A for 60 minutes; 3, desquamation: adding 2-4% of sodium sulfide and 2-3% of sodium hydroxide, treating for 18-24 hours, and draining; and 4, washing with water. According to the method, the penetrant and the alkali expansion inhibitor are added in proportion for pretreatment, the high pH value is inevitable in order to guarantee the descaling effect, but the crocodile skin can be prevented from being excessively degraded under the high pH value by inhibiting alkali expansion, the descaling effect is guaranteed, the crocodile skin can be prevented from being excessively damaged, and unity of contradictions is achieved.

Description

Technical Field

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

[0002] Crocodile leather has become an important part of the leather industry. As a high-end special 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. The Nile crocodiles, saltwater crocodiles, Siamese crocodiles and American alligators that have been farmed on a large scale have all been successfully bred. There are also sufficient sources of crocodile raw material leathers. However, there are very few independently developed crocodile leather processing technologies that can be used for actual production in actual production. This has greatly restricted the growth and development of the special leather processing industry. However, unlike other leather processing processes, the processing of crocodile leather is particularly important for the treatment of scales. The removal of scales often requires relatively violent chemical reactions. For example, under the action of alkali sulfide and lime, or alkali sulfide and sodium hydroxide, the disulfide bonds in the keratin in the scales will be destroyed and dissolved, causing the scales to fall off.

[0003] Although the removal of crocodile skin scales is similar to the dehairing process of other leather production, the processing requirements are different. The scales in crocodile skin are relatively hard and difficult to remove, so the amount of alkali sulfide and alkali used is relatively large. The fiber structure of the crocodile skin is relatively weak. Under the action of large amounts of alkali sulfide and alkali, the structure of the crocodile skin will be destroyed, resulting in a decrease in strength. On the contrary, if the amount of alkali sulfide and alkali is reduced in order to protect the fiber structure of the crocodile skin, the effect of removing the scale layer will be weakened and the treatment effect will not be achieved. Therefore, the contradiction between the descaling effect and the protection of the skin layer in the crocodile skin production process affects the production of crocodile skin. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a method for descaling crocodile skin, which has the advantages of ensuring the descaling effect and preventing the crocodile skin from being excessively damaged, thereby solving the above-mentioned problems.

[0006] (II) Technical solution

[0007] In order to achieve the above-mentioned purpose of ensuring the descaling effect and preventing the crocodile skin from being excessively damaged, the present invention provides the following technical solution: a descaling method for crocodile skin, comprising the following steps:

[0008] Step 1: Raw materials: crocodile skin after soaking and defatting, and use this as the basis for weight measurement;

[0009] Step 2: Pretreatment: 300% water, 1% penetrant, 2-4% alkali swelling inhibitor A, treatment for 60 minutes;

[0010] Step 3: Descaling: Add 2-4% alkali sulfide and 2-3% sodium hydroxide, treat for 18-24 hours, and control to dry;

[0011] Step 4: Wash with water.

[0012] Preferably, the pretreatment in step 2 may also be: 300% water, 1% penetrant, 2-4% alkali swelling inhibitor C, and the treatment lasts for 60 minutes.

[0013] Preferably, the descaling in step three may also be performed by adding 3-5% sodium sulfide and 3-5% calcium hydroxide, treating for 18-24 hours, and controlling to dryness.

[0014] Preferably, the penetrant is a nonionic surfactant.

[0015] Preferably, the alkali swelling inhibitor A is a mixture of sodium sulfate, sodium carbonate, sodium nitrate, calcium chloride, calcium nitrate, a cationic surfactant and an alcohol amine.

[0016] Preferably, the alkali swelling inhibitor C is a mixture of barium chloride, calcium chloride, calcium nitrate, barium nitrate, a cationic surfactant and an alcohol amine.

[0017] Compared with the prior art, the present invention provides a method for descaling crocodile skin, which has the following beneficial effects:

[0018] The present invention performs pretreatment by adding a penetrant and an alkali swelling inhibitor in proportion. Since a high pH value is inevitable to ensure the descaling effect, excessive degradation of the crocodile skin at a high pH value can be prevented by inhibiting alkali swelling, thereby ensuring the descaling effect and preventing the crocodile skin from being excessively damaged, thereby achieving a unity of contradictions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flow chart of Embodiment 1 of the present invention;

[0020] Figure 2 This is a flow chart of Embodiment 2 of the present invention;

[0021] Figure 3 This is a schematic diagram of the expansion degree of crocodile skin;

[0022] Figure 4 Schematic diagram of the cortical loss of crocodile skin. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in 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 creative work are within the scope of protection of the present invention.

[0024] See also Figure 1 , Embodiment 1:

[0025] A method for descaling crocodile skin comprises the following steps:

[0026] Step 1: Raw materials: crocodile skin after soaking and defatting, and use this as the basis for weight measurement;

[0027] Step 2: Pretreatment: 300% water, 1% penetrant, 2-4% alkali swelling inhibitor A, treatment for 60 minutes;

[0028] Step 3: Descaling: Add 2-4% alkali sulfide and 2-3% sodium hydroxide, treat for 18-24 hours, and control to dry;

[0029] Step 4: Wash with water.

[0030] The above-mentioned penetrant is a nonionic surfactant, and the alkali swelling inhibitor A is a mixture of sodium sulfate, sodium carbonate, sodium nitrate, calcium chloride, calcium nitrate, a cationic surfactant, and an alcohol amine.

[0031] See also Figure 2 , Embodiment 2:

[0032] A method for descaling crocodile skin comprises the following steps:

[0033] Step 1: Raw materials: crocodile skin after soaking and defatting, and use this as the basis for weight measurement;

[0034] Step 2: Pretreatment: 300% water, 1% penetrant, 2-4% alkali swelling inhibitor C, treatment for 60 minutes;

[0035] Step 3: Descaling: Add 3-5% sodium sulfide and 3-5% calcium hydroxide, treat for 18-24 hours, and control to dry;

[0036] Step 4: Wash with water.

[0037] The above-mentioned penetrant is a nonionic surfactant, and the alkali swelling inhibitor C is a mixture of barium chloride, calcium chloride, calcium nitrate, barium nitrate, a cationic surfactant, and an alcohol amine.

[0038] See also Figure 3It is a comparison of the crocodile skin descaling effect under the inhibition of alkali expansion and traditional alkaline descaling. Different parts of the crocodile skin were taken, and the two descaling methods were compared, and the expansion degree was measured. The results show that in the descaling method using the inhibition of alkali expansion, the expansion degree of each part is inhibited and relatively uniform. The expansion degree of the softest part is reduced from 120% to about 20%, the alkali expansion degree is reduced by more than 70% on average, and the expansion of the difference between parts is effectively inhibited.

[0039] See also Figure 4 Different parts of crocodile skin were taken and the two descaling methods were compared. The hydroxyproline content in the waste liquid was determined. The lower the hydroxyproline content, the less cortical degradation. Figure 2 It can be seen from the results that the descaling method of inhibiting alkali expansion can effectively reduce the cortical loss in various parts, and is more effective in reducing the cortical loss in soft parts. This also shows that the differences in parts of crocodile skin can be effectively reduced.

[0040] When animal skin expands in acid or alkali, the skin fibers will be damaged and degraded. This degradation is composed of two parts. One part of the degradation is the chemical action of acid or alkali, and the other part of the degradation is the mechanical damage caused by the expansion stress of the skin fibers. In the descaling process of crocodile skin, in order to ensure the descaling effect, there must be a sufficiently high amount of alkali sulfide and alkali, and a relatively high pH value must be maintained, which will lead to a relatively high degree of skin expansion, and the crocodile skin will be degraded by high pH and high expansion at the same time. Since a high pH value is inevitable to ensure the descaling effect, the excessive degradation of the crocodile skin at high pH can be prevented by inhibiting alkali expansion, which not only ensures the descaling effect but also reduces the damage to the cortex, achieving a unity of contradictions.

[0041] Under alkaline conditions, the amino groups on the skin collagen fibers are blocked and have no charge, while the collagen carboxyl groups are in an ionized state and have a negative charge. The electrostatic repulsion between the negative charges causes the collagen fibers to swell. In the application of this patent, a relatively high concentration of cations is added to block the collagen carboxyl groups and reduce the amount of negative charge on the collagen carboxyl groups, thereby reducing the degree of expansion of the skin under alkaline conditions.

[0042] The cations in the inhibitor of the present invention can be combined with the collagen carboxyl groups, especially the divalent calcium ions, barium ions and organic cations can be firmly combined with the collagen carboxyl groups, which can effectively block the collagen carboxyl groups, prevent the ionization of the collagen carboxyl groups, and reduce the number of negative charges of the collagen carboxyl groups, thereby reducing the alkaline expansion of the skin, reducing the cortical loss of crocodile skin during the alkaline descaling process, and effectively protecting the strength of the crocodile skin.

[0043] 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 descaling crocodile skin, characterized in that: The following steps are involved: Step 1: Raw materials: crocodile skin after soaking and defatting, and use this as the basis for weight measurement; Step 2: Pretreatment: 300% water, 1% penetrant, 2-4% alkali swelling inhibitor A, treatment for 60 minutes; Step 3: Descaling: Add 2-4% alkali sulfide and 2-3% sodium hydroxide, treat for 18-24 hours, and control to dry; Step 4: Wash with water.

2. The method for descaling crocodile skin according to claim 1, characterized in that: The pretreatment in step 2 may also be: 300% water, 1% penetrant, 2-4% alkali swelling inhibitor C, and the treatment lasts for 60 minutes.

3. The method for descaling crocodile skin according to claim 1, characterized in that: The descaling in step 3 may also be performed by adding 3-5% sodium sulfide and 3-5% calcium hydroxide, treating for 18-24 hours, and controlling to dryness.

4. The method for descaling crocodile skin according to claim 1, characterized in that: The penetrant is a nonionic surfactant.

5. The method for descaling crocodile skin according to claim 1, characterized in that: The alkali swelling inhibitor A is a mixture of sodium sulfate, sodium carbonate, sodium nitrate, calcium chloride, calcium nitrate, a cationic surfactant and an alcohol amine.

6. The method for descaling crocodile skin according to claim 2, characterized in that: The alkali swelling inhibitor C is a mixture of barium chloride, calcium chloride, calcium nitrate, barium nitrate, a cationic surfactant and an alcohol amine.

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