A method for ashless preparation of greenfin pufferfish leather

Abstract

This invention relates to a method for preparing greenfin filefish leather without ash treatment, belonging to the field of leather processing. The method includes batching, fleshing, weighing, soaking, degreasing, washing, weighing, pickling, tanning, washing, weighing, rewetting, retanning, neutralization, dyeing, fatliquoring, and drying. Compared with conventional processes, the fish leather processed using this method reduces the two steps of ash soaking and deashing, reduces the use of chemical raw materials, and alleviates environmental pollution. In this method, the fish skin is not treated with ash and alkali, resulting in a better leather surface condition during processing. The finished leather is full and soft, with scales adhering without falling off, and is aesthetically pleasing and fashionable.

Description

Technical Field

[0001] This invention belongs to the field of leather processing technology, specifically relating to a method for preparing greenfin filefish leather without ash. Background Technology

[0002] The greenfin filefish, also known as the filefish or skinfish, has an approximately oval body shape. It is distributed in the waters of Korea, Japan, southern Africa, and the East China Sea, Yellow Sea, and Bohai Sea of ​​my country. It is easy to catch and has a high yield. Since the 1980s, it has been the second most important economic fish species in China's marine fishing industry.

[0003] Greenfin filefish have high economic value; fish weighing over 100g can be marketed, and processed byproducts can be used to produce fishmeal, cod liver oil, and collagen. In recent years, with the decline of wild greenfin filefish resources and breakthroughs in artificial breeding technology, their aquaculture industry has gradually emerged.

[0004] The greenfin filefish has a tough skin with small scales and a strong connection between the skin and dermis. The skin is tough and easy to peel, but has low edible value. It is typically processed by removing the head, skin, and internal organs before being consumed or transported. Currently, the utilization rate of greenfin filefish skin is low due to its toughness and low value, and it is often discarded as waste. This not only wastes valuable biological resources but also pollutes the environment.

[0005] The scale structure of the greenfin filefish skin, which combines the base plate with the spines, gives the skin a unique frosted feel. Its skin is also highly tear-resistant and flexible. Processing the greenfin filefish skin into leather and then into leather products will significantly increase the economic value of the greenfin filefish.

[0006] CN116516079A discloses a method for producing wet blue leather from greenfin filefish skin while preserving its scales. This method describes soaking the greenfin filefish skin in water, pre-degreasing, liming and degreasing, deliming and degreasing, softening, pickling, deacidification, chrome tanning, and drying to obtain wet blue leather, but does not perform further processing to transform it into fish leather. Furthermore, in the liming and deliming steps of the method, the conventional liming process using alkali sulfide and quicklime causes the raw hide to swell and loosen the collagen fibers, while simultaneously dissolving the collagen, resulting in varying degrees of damage to the leather surface. Summary of the Invention

[0007] The purpose of this invention is to provide an ashless method for preparing greenfin filefish leather. This method involves treating the fish skin to produce greenfin filefish leather with scales. By extending the alkaline immersion environment, this invention achieves the goal of loosening collagen fibers, thereby saving time, resources, and manpower in leather tanning, better utilizing greenfin filefish skin resources, and increasing the variety of leather products.

[0008] This invention provides a method for preparing greenfin filefish leather without ash, comprising the steps of soaking in water, degreasing, acid soaking, tanning, alkali extraction, rehydration, retanning, neutralization, dyeing, fatliquoring, and drying to obtain greenfin filefish leather.

[0009] The specific steps for soaking and degreasing are as follows: Place the greenfin pufferfish skin in a rotating drum, add 400-800% water to the drum, adjust the temperature to 20-35℃, add 0.1-1.2% soaking aid, 0.2-1.2% degreasing agent, and 0.1-0.6% bactericide, control the pH of the bath solution to 7.0-10.0, rotate for 3-15 minutes, stop for 30-50 minutes, and combine rotation and stop for 6.5-8 hours, then drain the liquid; the amount of materials used is based on the weight of the raw skin.

[0010] Further, the specific steps of the acid soaking are as follows: place the greenfin pufferfish skin in a rotating drum, add water at a weight of 20-300%, adjust the temperature to 15-30℃, add 8-50% neutral salt, rotate for 5-15 minutes, and then use acid to lower the pH to 3.0-6.0 before tanning.

[0011] Further, the specific steps of the tanning process are as follows: after pickling, 20-90% of the pickling solution is reserved in the drum, and 0.5-5% of aldehyde tanning agent is added in two batches, with a rotation time of 10-60 minutes between the two additions.

[0012] Further, the specific steps for alkali extraction are as follows: after tanning, add 0.1-1% alkaline substance in multiple portions with an interval of 10-60 minutes; until the pH of the bath solution rises to 5.0-8.0, then adjust the drum temperature to 35-45℃, add 20-80% water, rotate for 120-360 minutes, and drain the solution.

[0013] Further, the specific steps of the rehumidification are as follows: Place the alkali-extracted greenfin pufferfish skin in a rotating drum, add 200-600% water to the drum, adjust the temperature to 30-35℃, and add 0.1-1.2% oxalic acid, 0.1-1% degreasing agent, and 0.2-0.6% formic acid; rotate for 30-60 minutes until the pH of the bath solution is 3.0-5.0, drain the solution, and then wash with water.

[0014] Further, the specific steps of the retanning are as follows: Place the rehydrated greenfin pufferfish skin in a rotating drum, add 100-200% water to the drum, adjust the temperature to 30-35℃, add 0.5-5% oxazolidine tanning agent, and rotate for 20-50 minutes; add 0.5-5% sulfone synthetic tanning agent, and rotate for 20-50 minutes; add 1-5% formic acid in 3 portions, with an interval of 20-50 minutes between each addition, and after the pH of the bath solution reaches 3-5, rotate for 20-50 minutes, add 3-8% chromium tanning agent and 0.2-1% fatliquoring agent in two portions, and rotate for 30-240 minutes. Then stop the drum and let it sit overnight. The next day, rotate for 30-60 minutes and drain the liquid.

[0015] Further, the specific steps of neutralization are as follows: add 100-300% water to the drum, adjust the temperature to 20-30℃, add 1-4% neutralizing retanning agent, and rotate for 20-50 minutes; add 1-3% sodium formate, rotate for 20-50 minutes, add 0.3-3% sodium bicarbonate in three portions, and rotate for 60-90 minutes until the pH of the bath solution is 3.0-6.0, then drain the solution.

[0016] Furthermore, the specific steps of the dyeing process are as follows: 1-3% disperse tannin and 0.1-3% dye are added to the drum, and after rotating for 30-60 minutes, the solution is replenished.

[0017] Further, the specific steps of the fatliquoring are as follows: add 50-100% of the fatliquoring agent into the drum, adjust the bath temperature to 40-55℃, add 1-5% protein filler, and rotate for 10-30 minutes; add 5-15% mixed fatliquoring agent, and rotate for 90-240 minutes; add 1-4% formic acid in 3 portions, with an interval of 15-30 minutes between each portion, adjust the pH of the soaking solution to 3.0-5, drain the solution, and wash with water.

[0018] Furthermore, the specific steps of the drying process are as follows: the washed fish leather is laid flat and fixed, and then dried in a cool place at a self-ignition temperature to obtain the green-finned pufferfish leather of the present invention.

[0019] The beneficial effects of this invention compared with the prior art are as follows:

[0020] This invention loosens the muscle fibers of greenfin filefish skin by extending the soaking time, while eliminating the two steps of soaking and deliming. Compared with conventional methods, the fish leather processed using this method has more intact and firm scales, and the skin thickness, tear strength, tensile strength, burst strength and elongation at break are all improved. At the same time, the method of this invention reduces the use of chemical raw materials, reduces environmental pollution, and saves leather processing time, manpower and material resources. Attached Figure Description

[0021] Figure 1 The scaled side of the fish leather prepared according to one embodiment of the present invention;

[0022] Figure 2 The flesh side of the fish leather prepared according to one embodiment of the present invention;

[0023] Figure 3 The scaled side of the fish leather prepared according to two embodiments of the present invention;

[0024] Figure 4 The fish skin prepared according to two examples of the present invention is shown below. Detailed Implementation

[0025] The technical solution of the present invention will be further explained below through specific embodiments, but the scope of protection of the present invention is not limited in any way by the embodiments.

[0026] All reagents in this embodiment are commercially available reagents, and the amount of all reagents or materials used is based on the weight of the greenfin pufferfish skin as a percentage by mass.

[0027] Example 1

[0028] Fish skin batching: Select some greenfin pufferfish skins that are relatively well-preserved and of similar size and thickness;

[0029] Remove the flesh and weigh: After removing any remaining fascia and impurities from the surface of the greenfin pufferfish skin, wash it with water, weigh it, and then proceed with the following steps.

[0030] Soaking and degreasing: Add water at 25°C to the drum, the amount of which is 600% of the weight of the greenfin pufferfish skin. Add 0.6% soaking aid (ES-10M), 0.6% degreasing agent (Eusapon OC), and 0.5% bactericide. Control the pH of the bath solution to 9.0. Rotate for 10 minutes, stop for 30 minutes, and combine rotation and stop for 8 hours. After draining the liquid, wash with water.

[0031] Acid treatment: Place the skin of the greenfin pufferfish in a rotating drum, add water equal to 200% of the skin's weight, adjust the temperature to 20℃, add 10% NaCl, rotate for 10 minutes, add 2% formic acid in three portions with a 10-minute interval between each addition, add 0.5% concentrated sulfuric acid in two portions, and add 1% formic acid in three portions with a 20-minute interval between each addition, until the pH is lowered to 3.5 for tanning.

[0032] Tanning: Add 5% glutaraldehyde tanning agent (GTA) to the 50% volume ratio of the pickling solution in the drum, in two additions, with an interval of 20 minutes between each addition;

[0033] Alkali extraction: After tanning, add 0.6% baking soda in multiple batches at 20-minute intervals to raise the pH of the bath to 6; then adjust the drum temperature to 40°C, add 20% water, rotate for 120 minutes, and drain; then perform routine water washing, remove from the drum, and let stand.

[0034] Rehydration: Place the greenfin pufferfish skin after alkali extraction in a rotating drum, add 200% water to the drum, adjust the temperature to 35℃, add 1% oxalic acid, 0.5% defatting agent (Eusapon OC), and 0.2% formic acid; rotate for 30 minutes, drain the bath solution when the pH is 4, and then wash with water;

[0035] Retanning: Place the rehydrated greenfin pufferfish skin in a rotating drum, add 100% water to the drum, adjust the temperature to 30℃, then add 2% oxazolidine tanning agent (OXB) and rotate for 20 minutes; add 3% sulfone synthetic tanning agent (OS) and rotate for 20 minutes; add 2% formic acid in 3 portions, 20 minutes apart each time, and after the pH of the bath solution reaches 3, rotate for 30 minutes; add 6% chromium tanning agent and 0.2% fatliquoring agent in two portions, rotate for 60 minutes, stop the drum and let it sit overnight; the next day, rotate for 30 minutes and drain the liquid.

[0036] Neutralization: Add water equal to 300% of the leather weight to the drum, adjust the temperature to 30℃, add 3% of neutralizing retanning agent (XNL), and rotate for 30 minutes; add 1% sodium formate and rotate for 30 minutes; add 1.5% sodium bicarbonate in three portions and rotate for 60 minutes each time, control the pH of the bath to 4.5, and drain the liquid.

[0037] Dyeing: Add 1% disperse tannin (JOM) and 1% dye (yellow-brown dye) to the drum and rotate for 30 minutes;

[0038] Fat addition: Add 80% water to the drum, adjust the bath temperature to 50℃, add 3% protein filler (FB), and rotate for 20 minutes; add 2% synthetic fatliquoring agent (94S), 2% lecithin (LC-13), and 2% lanolin (ZLN), and rotate for 120 minutes; add 2.5% formic acid in 3 portions, 20 minutes apart each time, adjust the pH of the soaking solution to 4, and drain the solution;

[0039] Water washing: Add 800% water to the drum, rotate for 5 minutes, drain the liquid, and remove from the drum.

[0040] Drying: Stretch, flatten, and fix the obtained fish skin, then dry it in a cool, shaded place. The resulting fish leather is as follows: Figure 1 and Figure 2 As shown.

[0041] The physical properties of the obtained fish leather were tested, and the test results are shown in Table 1 below.

[0042] Table 1. Physical property tests of greenfin filefish leather.

[0043] 1 2 3 Thickness (mm) 0.65 0.67 0.64 Tear strength (N / mm) 18.95 19.32 20.62 Tensile strength (N / mm) 15.16 15.26 16.16 <![CDATA[Burst strength (N / mm 2 )]]> 190.60 180.30 175.10 Elongation at break (%) 43.34 46.44 45.26

[0044] Example 2

[0045] Fish skin batching: Select some greenfin pufferfish skins that are relatively well-preserved and of similar size and thickness;

[0046] Meat removal and weighing: After removing some remaining fascia and impurities from the surface of the greenfin pufferfish skin, it is washed, weighed, and the chemical calculations for the soaking and degreasing processes are based on the quality of the fish skin.

[0047] Soaking: Add water at 25°C to the drum, the amount of which is 600% of the weight of the greenfin pufferfish skin. Add 0.6% soaking aid (ES-10M), 0.6% degreasing agent (Eusapon OC), and 0.5% bactericide. Control the pH of the bath solution to 9.0. Rotate for 10 minutes, stop for 30 minutes, and combine rotation and stop for 5 hours. After draining the liquid, wash with water.

[0048] Lime impregnation: Add water at 25℃ to the drum, along with 2% sodium sulfide, 3.0% lime, 1.0% impregnation aid (MB), and 1.0% degreasing agent (Eusapon OC). Rotate the drum for 70 minutes, then add another 1.0% lime and 0.5% impregnation aid. Control the pH at around 12, rotate for 60 minutes, and then drain the liquid.

[0049] Deashing: Add water at 25°C, 1.0% ammonium sulfate, 2.0% deashing agent (ASB), and 500% water to the drum; rotate for 50 minutes, drain the liquid, and wash with water.

[0050] Acid treatment: Place the skin of the greenfin pufferfish in a rotating drum and add water with a mass of 200% of its weight. Adjust the temperature to 20°C, add 10% NaCl, and rotate for 10 minutes. Add 2% formic acid in three portions, with an interval of 10 minutes between each addition. Add 0.5% concentrated sulfuric acid in two portions. Add 1% formic acid in three portions, with an interval of 20 minutes between each addition. Lower the pH to 3.5 for tanning.

[0051] Tanning: Add 5% glutaraldehyde tanning agent (GTX) to the 50% volume ratio of the pickling solution in the drum, in two additions, with an interval of 20 minutes between each addition;

[0052] Alkali extraction: After tanning, add 0.6% baking soda in multiple batches to raise the pH of the bath solution to 6; then adjust the drum temperature to 40℃, add 20% water, rotate for 120 minutes, and drain the solution; then perform routine water washing, remove from the drum, and let stand.

[0053] Rehumidification: In the drum, add 200% water, adjust the temperature to 35℃, add 1% oxalic acid, 0.5% degreasing agent (EusaponOC), and 0.2% formic acid; rotate for 30 minutes, drain the bath solution when the pH is 4, and then wash with water.

[0054] Retanning: Add 100% water and 2% oxazolidine tanning agent (OXB) to the drum and rotate for 20 minutes; add 3% sulfone synthetic tanning agent (OS) and rotate for 20 minutes; add 2% formic acid in 3 portions, 20 minutes apart each time. After the pH of the bath reaches 3, rotate for 30 minutes. Add 6% chromium tanning agent and 0.2% fatliquoring agent in two portions and rotate for 60 minutes. Stop the drum and let it sit overnight. The next day, rotate for 30 minutes and drain the liquid.

[0055] Neutralization: Add water equal to 300% of the leather weight to the drum, adjust the temperature to 30℃, add 3% of neutralizing retanning agent (XNL), and rotate for 30 minutes; add 1% sodium formate and rotate for 30 minutes; add 1.5% sodium bicarbonate and rotate for 60 minutes, control the pH of the bath to 4.5, and drain the liquid;

[0056] Fat-adding process: Add 80% water to the drum, adjust the bath temperature to 50℃, add 3% protein filler (FB), and rotate for 20 minutes; add 2% synthetic fat-adding agent (94S), 2% lecithin (LC-13), and 2% lanolin (ZLN), and rotate for 90-120 minutes; add 2.5% formic acid in 3 portions, with an interval of 10 minutes between each addition, adjust the pH of the soaking solution to 4, and drain the solution;

[0057] Water washing: Add 800% water to the drum, rotate for 5 minutes, drain the liquid, and remove from the drum.

[0058] Drying: Stretch, flatten, and fix the obtained fish skin, then dry it in a cool, shaded place. The fish skin will resemble... Figure 3 and Figure 4 As shown.

[0059] The performance tests of the greenfin pufferfish leather prepared by the above method are shown in Table 2.

[0060] Table 2. Physical property tests of greenfin filefish leather.

[0061] 1 2 3 Thickness (mm) 0.52 0.60 0.62 Tear strength (N / mm) 16.37 17.06 18.23 Tensile strength (N / mm) 14.13 12.16 13.12 <![CDATA[Burst strength (N / mm 2 )]]> 150.27 140.26 155.35 Elongation at break (%) 42.38 45.66 44.56 .

Claims

1. A method for preparing greenfin filefish leather without ash, characterized in that, The method includes the following steps in sequence: soaking in water, degreasing, soaking in acid, tanning, alkali extraction, rehydration, retanning, neutralization, dyeing, fat addition and drying, to produce greenfin filefish leather; The specific steps for soaking and degreasing are as follows: Place the greenfin pufferfish skin in a rotating drum, add 400-800% water, adjust the temperature to 20-35℃, add 0.1-1.2% soaking aid, 0.2-1.2% degreasing agent, and 0.1-0.6% bactericide, control the pH of the bath solution to 7.0-10.0, rotate for 3-15 minutes, stop for 30-50 minutes, combine rotation and stop for 6.5-8 hours, and then drain the liquid; the amount of materials used is based on the weight of the greenfin pufferfish skin. The specific steps of the dyeing process are as follows: After neutralization, add 1-3% disperse tannin and 0.1-3% dye to the drum, rotate for 30-60 minutes, and then replenish the solution. The specific steps for fatliquoring are as follows: After staining, add 50-100% water to the drum, adjust the bath temperature to 40-55℃, add 1-5% protein filler, and rotate for 10-30 minutes; add 5-15% mixed fatliquoring agent, and rotate for 90-240 minutes; add 1-4% formic acid in 3 portions, with an interval of 15-30 minutes between each portion, adjust the pH of the soaking solution to 3.0-5, drain the solution, and wash with water.

2. The method for preparing greenfin filefish leather without ash according to claim 1, characterized in that, The specific steps of the acid immersion process are as follows: the soaked and degreased greenfin pufferfish skin is placed in a rotating drum, 20-300% water by weight is added, the temperature is adjusted to 15-30℃, 8-50% neutral salt is added, and after rotating for 5-15 minutes, the pH is lowered to 3.0-6.0 with acid before tanning. The amount of materials used is based on the weight of the greenfin pufferfish skin.

3. The method for preparing greenfin filefish leather without ash according to claim 2, characterized in that, The specific steps of the tanning process are as follows: after immersion in acid, 20-90% of the immersion solution is reserved in the drum, and 0.5-5% of aldehyde tanning agent is added in two batches, with a rotation time of 10-60 minutes between the two additions. The amount of material used is based on the weight of the greenfin pufferfish skin.

4. The method for preparing greenfin filefish leather without ash according to claim 3, characterized in that, The specific steps for alkali extraction are as follows: After tanning, add 0.1-1% alkaline substance in multiple portions at intervals of 10-60 minutes; until the pH of the bath solution rises to 5.0-8.0, then adjust the drum temperature to 35-45℃, add 20-80% water, rotate for 120-360 minutes, and drain the liquid. The amount of materials used is based on the weight of the greenfin pufferfish skin.

5. The method for preparing greenfin filefish leather without ash according to claim 4, characterized in that, The specific steps for rehydration are as follows: Place the alkali-extracted greenfin pufferfish skin in a rotating drum, add 200-600% water to the drum, adjust the temperature to 30-35℃, and add 0.1-1.2% oxalic acid, 0.1-1% degreasing agent, and 0.2-0.6% formic acid; rotate for 30-60 minutes until the pH of the bath solution is 3.0-5.0, drain the solution, and then wash with water.

6. The method for preparing greenfin filefish leather without ash according to claim 5, characterized in that, The specific steps of the retanning process are as follows: Place the rehydrated greenfin pufferfish skin in a rotating drum, add 100-200% water to the drum, adjust the temperature to 30-35℃, add 0.5-5% oxazolidine tanning agent, and rotate for 20-50 minutes; add 0.5-5% sulfone synthetic tanning agent, and rotate for 20-50 minutes; add 1-5% formic acid in 3 portions, with an interval of 20-50 minutes between each addition, and after the pH of the bath solution reaches 3-5, rotate for 20-50 minutes, add 3-8% chromium tanning agent and 0.2-1% fatliquoring agent in two portions, and rotate for 30-240 minutes. Stop the drum and let it sit overnight. The next day, rotate for 30-60 minutes and drain the liquid.

7. The method for preparing greenfin filefish leather without ash according to claim 6, characterized in that, The specific steps for neutralization are as follows: After retanning, add 100-300% water to the drum, adjust the temperature to 20-30℃, add 1-4% neutralizing retanning agent, and rotate for 20-50 minutes; add 1-3% sodium formate, and rotate for 20-50 minutes; add 0.3-3% sodium bicarbonate in three portions, and rotate for 60-90 minutes until the pH of the bath solution is 3.0-6.0, then drain the solution.

8. The method for preparing greenfin filefish leather without ash according to claim 1, characterized in that, The specific steps of the drying process are as follows: after the fish leather is washed with oil, it is laid flat and fixed, and then dried in the shade at a natural temperature to obtain greenfin pufferfish leather.

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