Method for raising the nap of a leather-white hide

Abstract

The application relates to the technical field of fur leather processing, and particularly discloses a napping treatment method for fur leather white embryo skins. The napping treatment method mainly comprises the following steps: S1, adding fur leather white embryo skins and water into a rotating drum; S2, adding a napping agent into the rotating drum and rotating for treatment; S3, repeating the step S2 operation at least once and draining liquid; and S4, adding water, a hand feel agent and an organic acid into the rotating drum, rotating for treatment, draining liquid and obtaining napped fur leather white embryo skins. The napping agent is mainly made of the following raw materials: potassium hydrogen persulfate, cyclohexanone peroxide, sulfonated succinic acid dioctyl ester sodium salt, dipropylene glycol methyl ether, isopropyl alcohol and water. The napped fur leather white embryo skins obtained by the napping treatment method have the advantages of small hair fineness, good fineness uniformity and good uniform distribution of fineness, and the fur surface is fine, smooth, soft, comfortable, natural and soft, which is beneficial to improving the quality, grade and market competitiveness of the fur leather and meeting market demands.

Description

Technical Field

[0001] This application relates to the field of fur and leather processing technology, and more specifically, it relates to a method for napping fur and leather raw hides. Background Technology

[0002] Fuzzy leather is a type of leather product with two sides: a fur side and a leather side. It is also a common everyday item, widely used in clothing, footwear, and furniture. The processing of fur leather mainly includes soaking, re-soaking, degreasing, pickling, white tanning, filling, and washing to obtain raw fur hide. This raw hide is then retanned, dyed, and dried to obtain the final fur leather. However, the applicant has found in actual processing that the raw fur hide obtained after white tanning has a coarser fur on the fur side, resulting in a less desirable feel and affecting the quality of the fur leather. Summary of the Invention

[0003] To reduce the average diameter of the hair and refine the hair, this application provides a method for napping raw leather, employing the following technical solution: The method for napping raw hides mainly includes the following steps: S1. Add raw leather and water to the drum; S2. Add the fluff treatment agent to the drum and rotate for 50-70 minutes. S3. Repeat step S2 at least once to drain the fluid; S4. Add water to the drum, then add a hand-feeling agent and organic acid, rotate for 20-40 minutes, drain the liquid, and complete the napping process to obtain napped white leather raw hide. The fluff treatment agent is mainly made from the following raw materials in parts by weight: 25-35 parts potassium persulfate, 15-25 parts cyclohexanone peroxide, 3-7 parts sodium dioctyl sulfosuccinate, 3-7 parts dipropylene glycol methyl ether, 80-120 parts isopropanol, and 80-120 parts water.

[0004] The method for napping raw leather in this application, through the cooperation of each step, enables the hair on the napped raw leather to have a low average diameter and coefficient of variation, with an average diameter <32μm and a coefficient of variation <26%. It exhibits the advantages of fine hair, good uniformity of thickness and distribution, and a delicate surface with a smooth, soft, comfortable, and naturally supple feel, which is conducive to improving the quality of the leather and meeting market demands.

[0005] Adding potassium persulfate and cyclohexanone peroxide to the raw materials of the napping agent has a good oxidizing effect. It can oxidize proteins and cause them to break down, thus destroying the hair on the surface of the raw leather and making it fluffy, soft, and enhancing its luster, softness, and elasticity. Furthermore, the synergistic effect between the two can improve the fineness of the hair, reduce the average diameter, and maintain good uniformity of hair thickness, thereby improving the feel and enhancing the napping effect. This results in napped raw leather with superior quality, which is beneficial for improving the grade and market competitiveness of the leather.

[0006] Optionally, in step S3, the operation of step S2 is repeated one to four times. Preferably, in step S3, the operation of step S2 is repeated one to three times.

[0007] By adopting the above technical solution, the number of repeated operations is limited, thereby limiting the number of times the fur treatment agent is added to the white fur hide. This reduces the situation where the average diameter is too high due to too few additions, and also reduces the situation where excessive damage to the hair is caused by too many additions. Furthermore, when the number of additions is two to four, the hair of the fur-treated white fur hide can maintain a good average diameter and coefficient of variation.

[0008] Optionally, the weight ratio of the raw leather and water in step S1 is 1:(10-20), and the weight ratio of the raw leather and the fur treatment agent is 1000:(4.3-4.7).

[0009] By adopting the above technical solution, the amount of water and napping agent added in step S1 is limited to ensure that the napping agent and the white leather are in full contact, and to fully oxidize the hair on the napping surface of the white leather, thereby reducing the average diameter, improving the uniformity of thickness, enhancing the napping effect, and achieving ideal softness and feel.

[0010] Optionally, the weight ratio of the raw leather and water in step S4 is 1:(10-20), and the weight ratio of the raw leather, hand feel agent, and organic acid is 1000:(7-9):(7-9).

[0011] By adopting the above technical solution, the amount of water, hand-feeling agent, and organic acid added in step S4 is limited to ensure that the raw leather and hand-feeling agent and organic acid are in full contact and penetrate, thereby enhancing the effect of the hand-feeling agent and organic acid and ensuring the effect of the napping treatment.

[0012] In several implementations, the weight ratio of raw leather and water in step S4 is 1:15. However, the weight ratio can also be set to 1:10, 1:11, 1:12, 1:13, 1:14, 1:16, 1:17, 1:18, 1:19, or 1:20 as needed. But it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0013] In several implementation schemes, the weight ratio of raw leather, hand feel agent, and formic acid is 1000:8:8. It can also be set to 1000:7:7, 1000:7:8, 1000:7:9, 1000:8:7, 1000:8:9, 1000:9:7, 1000:9:8, or 1000:9:9 as needed. However, it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0014] Optionally, the hand feel agent is one or more of the following: hand feel agent LM-3032, hand feel agent XH-A50, hand feel agent XH-A90, hand feel agent AD4003, and hand feel agent AD4005.

[0015] By adopting the above technical solution, the hand feel agent is limited, which facilitates the selection of the hand feel agent. Moreover, hand feel agents LM-3032, XH-A50, XH-A90, AD4003, and AD4005 can all effectively improve the softness and elasticity of raw fur leather, giving the fur leather a better feel and durability.

[0016] Optionally, the organic acid is one or more of formic acid, acetic acid, propionic acid, butyric acid, malic acid, and citric acid.

[0017] By adopting the above technical solution, the organic acids are limited, which facilitates the selection of organic acids.

[0018] Optionally, in step S1, the water temperature is 40-50℃; in step S2, the water temperature is 10-30℃.

[0019] By employing the above technical solution, the temperature of the water in step S1 is limited to ensure the treatment effect of the napping agent on the raw leather hide. The temperature of the water in step S2 is also limited to facilitate the treatment of the raw leather hide by the hand-feeling agent and organic acids, ensuring the uniformity and stability of the napped raw leather hide.

[0020] In several implementations, in step S2, the water temperature is 23°C. It can also be set to 10°C, 15°C, 20°C, 25°C, or 30°C as needed, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] Optionally, the average diameter of the hairs on the surface of the raw leather hide is 35-50 μm.

[0022] By adopting the above technical solution, the average diameter of the hairs on the surface of the raw leather hide is limited, ensuring the stability of the raw leather hide source and facilitating the napping process. In several embodiments, the average diameter of the hairs on the surface of the raw leather hide is 38.67 μm. However, the average diameter can also be set to 35 μm, 40 μm, 45 μm, or 50 μm as needed, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0023] Optionally, the raw materials of the fluff treatment agent may also include 4-6 parts by weight of a fluorinated surfactant.

[0024] By adopting the above technical solution, adding a fluorinated surfactant to the napping agent and utilizing its interaction with sodium dioctyl sulfosuccinate enhances permeability and uniformity, which is beneficial to improving the synergistic effect between potassium persulfate and cyclohexanone peroxide, reducing the average hair diameter on the napped surface of the white fur, improving the uniformity of hair diameter and distribution, and thus improving the quality of the fur.

[0025] Optionally, the fluorinated surfactant is a sodium sulfonate fluorinated surfactant, which is prepared by the following method: T1. Under the protection of an inert gas at a temperature of 40-60℃, ethanol and p-phenylenediamine are mixed, and then trifluoroethyl acrylate is added dropwise over a period of 50-70 minutes. After the addition is complete, the mixture is stirred for 18-22 hours, and then the ethanol is removed by vacuum distillation to obtain a fluorine-containing intermediate. T2. At a temperature of 70-80℃ and under inert gas protection, acetonitrile and fluorine-containing intermediates are mixed, and then 2,4-butane sulfonyl lactone is added. The mixture is stirred for 18-22 hours, cooled to room temperature, filtered, and washed to obtain sulfonic acid fluorine-containing intermediates. T3. At a temperature of 40-60℃, water and fluorinated sulfonic acid intermediates are mixed, then sodium ethoxide is added, and the mixture is stirred for 8-12 hours. After drying to constant weight, sodium sulfonate fluorinated surfactant is obtained.

[0026] Optionally, the weight ratio of p-phenylenediamine, trifluoroethyl acrylate, 2,4-butanesulfonyl lactone, and sodium ethoxide is 10:(12-17):(11-14):(5-8).

[0027] By employing the above technical solution, p-phenylenediamine contains two amino groups. First, fluorine is introduced by an addition reaction between the carbon-carbon double bond in trifluoroethyl acrylate and one amino group in p-phenylenediamine, yielding a fluorinated intermediate. Then, a ring-opening reaction is conducted between the sulfonyl group in 2,4-butanesulfonyl lactone and the remaining amino group in p-phenylenediamine, introducing a sulfonic acid group, yielding a fluorinated sulfonic acid intermediate. Subsequently, an acid-base reaction is conducted between the sodium group in sodium ethoxide and the sulfonic acid group, introducing a sodium group, yielding a sodium sulfonate salt fluorinated surfactant. The preparation method of this application not only facilitates the preparation of sodium sulfonate salt fluorinated surfactants but also introduces sodium sulfonate and fluorine groups, effectively increasing wettability and penetration. This allows the napping agent to penetrate more easily into the internal structure of the hair, enhancing the napping effect, reducing the average diameter and coefficient of variation, making the hair thickness more uniform, improving distribution uniformity, and also giving the fur leather a better feel and quality.

[0028] In several embodiments, the weight ratio of p-phenylenediamine, trifluoroethyl acrylate, 2,4-butanesulfonyl lactone, and sodium ethoxide is 10:14.4:12.6:6.3. This ratio can also be set to 10:12:11:5, 10:12:11:8, 10:12:14:5, 10:12:14:8, 10:17:11:5, 10:17:11:8, 10:17:14:5, or 10:17:14:8 as needed, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0029] Optionally, the weight ratio of p-phenylenediamine to ethanol is 1:(8-12).

[0030] By adopting the above technical solution and limiting the amount of ethanol added, it is beneficial to the uniform dispersion of phenylenediamine and trifluoroethyl acrylate, as well as their full contact and reaction, reducing the occurrence of side reactions and ensuring the stability and effectiveness of the sodium sulfonate fluorinated surfactant. In several embodiments, the weight ratio of phenylenediamine to ethanol is 1:10, but it can also be set to 1:8, 1:9, 1:11, or 1:12 as needed, but it is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0031] Optionally, the weight ratio of p-phenylenediamine to acetonitrile is 1:(8-12).

[0032] By adopting the above technical solution and limiting the amount of acetonitrile added, it is beneficial to the uniform dispersion of the fluorinated intermediate and 2,4-butanesulfonyl lactone, as well as to their full contact and reaction, reducing the occurrence of side reactions and ensuring the stability and performance of the sodium sulfonate fluorinated surfactant. In several embodiments, the weight ratio of p-phenylenediamine to acetonitrile is 1:10, but it can also be set to 1:8, 1:9, 1:11, or 1:12 as needed, but it is not limited to the values ​​listed; other unlisted values ​​within this range are also applicable.

[0033] Optionally, the weight ratio of p-phenylenediamine to water is 1:(8-12).

[0034] By adopting the above technical solution and limiting the amount of water added, it is beneficial to the uniform dispersion of the fluorinated sulfonic acid intermediate and sodium ethoxide, as well as to their full contact and reaction, reducing the occurrence of side reactions and ensuring the stability and effectiveness of the sodium sulfonate fluorinated surfactant preparation. In several embodiments, the weight ratio of p-phenylenediamine to water is 1:10, but it can also be set to 1:8, 1:9, 1:11, or 1:12 as needed, but it is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0035] In several embodiments, the dripping time of trifluoroethyl acrylate is 60 min. However, the dripping time can also be set to 50 min, 52 min, 55 min, 57 min, 62 min, 65 min, 67 min, or 70 min as needed, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] The leather is obtained by using the aforementioned method for napping the raw leather hide, which involves napping the raw leather hide, followed by retanning, dyeing, and drying.

[0037] In summary, this application has at least the following beneficial effects: The method for napping raw leather in this application involves simultaneously adding potassium persulfate and cyclohexanone peroxide to the raw materials of the napping agent. Utilizing the synergistic effect of these two substances, the nap on the surface of the raw leather becomes fluffy and soft, increasing its luster, softness, and elasticity. This improves the fineness of the hair, reduces its average diameter, maintains good uniformity in hair thickness, improves the feel, and enhances the napping effect. The average hair diameter is <32μm, and the coefficient of variation is <26%. This method exhibits advantages such as fine hair, good uniformity in hair thickness, and even distribution of hair thickness. Furthermore, the nap is delicate, smooth, soft, comfortable, and naturally supple, which helps improve the quality, grade, and market competitiveness of the leather, meeting market demands. Detailed Implementation

[0038] To make this application easier to understand, the following detailed description will be provided with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of application of this application. Unless otherwise specified, the raw materials or components used in this application can be obtained commercially or by conventional methods.

[0039] Preparation Example Table 1. Amounts of each raw material used in the fluff treatment agent (unit: kg) Potassium persulfate 30 25 35 30 30 Cyclohexanone peroxide 20 25 15 20 20 Sodium dioctyl sulfosuccinate 5 7 3 5 5 Dipropylene glycol methyl ether 5 3 7 5 5 Isopropanol 100 80 120 100 100 water 100 120 80 100 100 Sodium sulfonate fluorinated surfactants 0 0 0 4 6 Preparation Example 1 A fluff treatment agent, the raw materials and their proportions are shown in Table 1.

[0040] A method for preparing a fluff treatment agent mainly includes the following steps: At a rotation speed of 300 rpm, isopropanol, sodium dioctyl sulfosuccinate, and dipropylene glycol methyl ether were added to water and stirred for 3 minutes. Then potassium persulfate was added and stirred for 3 minutes. Finally, cyclohexanone peroxide was added and stirred for 3 minutes to obtain the fluff treatment agent.

[0041] Preparation Example 2 A fluff treatment agent differs from Preparation Example 1 in that the raw material ratio of the fluff treatment agent is different, and the raw material ratio of the fluff treatment agent is shown in Table 1.

[0042] Preparation Example 3 A fluff treatment agent differs from Preparation Example 1 in that the raw material ratio of the fluff treatment agent is different, and the raw material ratio of the fluff treatment agent is shown in Table 1.

[0043] Preparation Example 4 A fluff treatment agent, the raw materials and their proportions are shown in Table 1.

[0044] The sodium sulfonate fluorinated surfactant is prepared using the following method: T1. Under nitrogen protection, at a rotation speed of 500 r / min and a temperature of 50℃, 10 kg of p-phenylenediamine was added to 100 kg of ethanol and stirred for 3 min. Then, 14.4 kg of trifluoroethyl acrylate was added dropwise over 60 min. After the addition was complete, the mixture was stirred for 20 h. The ethanol was then removed by vacuum distillation to obtain a fluorine-containing intermediate.

[0045] T2. Under nitrogen protection, at a rotation speed of 300 r / min and a temperature of 75℃, the fluorine-containing intermediate obtained in step T1 was added to 100 kg of acetonitrile and stirred for 3 min. Then, 12.6 kg of 2,4-butanesulfonyl lactone was added, and the mixture was stirred for 20 h, followed by cooling to 25℃. The mixture was then filtered and washed three times with acetonitrile, with 200 kg of acetonitrile used each time, to obtain the fluorine-containing sulfonic acid intermediate.

[0046] T3. At a speed of 300 r / min and a temperature of 50℃, the sulfonic acid fluorinated intermediate obtained in step T2 was added to 100 kg of water and stirred for 3 min. Then, 6.3 kg of sodium ethoxide was added and stirred for 10 h. Afterward, it was dried to constant weight at a temperature of 90℃ to obtain the sodium sulfonate fluorinated surfactant.

[0047] A method for preparing a fluff treatment agent mainly includes the following steps: At a rotation speed of 300 rpm, isopropanol, sodium dioctyl sulfosuccinate, sodium sulfonate fluorinated surfactant, and dipropylene glycol methyl ether were added to water and stirred for 3 minutes. Then potassium persulfate was added and stirred for 3 minutes. Finally, cyclohexanone peroxide was added and stirred for 3 minutes to obtain the fluff treatment agent.

[0048] Preparation Example 5 A fluff treatment agent differs from Preparation Example 4 in that the raw material ratio of the fluff treatment agent is different, and the raw material ratio of the fluff treatment agent is shown in Table 1.

[0049] Preparation Example 6 A fluffing agent, which differs from Preparation Example 4 in that, in the raw materials of the fluffing agent, an equal amount of fluorinated surfactant is used to replace the sodium sulfonate fluorinated surfactant, and the fluorinated surfactant is a fluorinated surfactant. FS-3100.

[0050] Preparation Example 7 A fluffing agent, which differs from Preparation Example 4 in that, in the raw materials of the fluffing agent, an equal amount of fluorinated surfactant is used to replace the sodium sulfonate fluorinated surfactant, and the fluorinated surfactant is a fluorinated surfactant. FS-10. Example

[0051] Example 1 A method for napping raw leather hides mainly includes the following steps: S0. Prepare raw leather, nap treatment agent, hand feel agent, and organic acid.

[0052] The raw wool hides are made from sheepskin through a series of processes including soaking, re-soaking, degreasing, pickling, white tanning, filling, and washing. Each raw wool hide weighs 1 kg, is 17 mm thick, and has an area of ​​1.1 m². 2 The moisture content is 13wt%, and the average diameter of the hair on the surface of each white leather hide is 38.67μm.

[0053] The fluff treatment agent was prepared using the method described in Preparation Example 1; the hand feel agent was hand feel agent LM-3032; and the organic acid was formic acid.

[0054] S1. At a rotation speed of 10 r / min, add 10 kg of raw wool hide and 150 kg of water at a temperature of 45°C to the drum.

[0055] S2. Add 60g of fluff treatment agent to the drum at a rotation speed of 10r / min and rotate for 60min.

[0056] S3. Repeat step S2 three times to drain the fluid.

[0057] S4. At a rotation speed of 10 r / min, add 150 kg of water at a temperature of 23°C to the drum, then add 80 g of hand-feeling agent and 80 g of organic acid, rotate for 30 min, drain the liquid, and complete the napping treatment to obtain napped white leather raw hide.

[0058] S5. The raw suede of the napped fur leather is successively retanned, dyed, and dried to obtain fur leather.

[0059] Examples 2-7 A method for fluffing white leather hides, which differs from Example 1 in that the source of the fluffing agent in step S0 is different, and the fluffing agents of Examples 2-7 are prepared sequentially using the methods of Preparation Examples 2-7.

[0060] Example 8 A method for napping white leather hides, which differs from Example 1 in that step S3 is different.

[0061] Step S3 specifically involves repeating step S2 four times to drain the fluid.

[0062] Example 9 A method for napping white leather hides, which differs from Example 1 in that step S3 is different.

[0063] Step S3 specifically involves repeating step S2 twice to drain the fluid.

[0064] Example 10 A method for napping white leather hides, which differs from Example 1 in that step S3 is different.

[0065] Step S3 specifically involves repeating step S2 once to drain the fluid.

[0066] Example 11 A method for napping white leather hides, which differs from Example 1 in that steps S1 and S2 are different.

[0067] Step S1 specifically involves adding 10 kg of raw wool hide and 100 kg of water at a temperature of 50°C to the drum at a rotation speed of 10 r / min.

[0068] Step S2 specifically involves adding 5g of fluff treatment agent to the drum at a rotation speed of 10r / min and rotating it for 70min.

[0069] Example 12 A method for napping white leather hides, which differs from Example 1 in that steps S1 and S2 are different.

[0070] Step S1 specifically involves adding 10 kg of raw wool hide and 200 kg of water at a temperature of 40°C to the drum at a rotation speed of 10 r / min.

[0071] Step S2 specifically involves adding 7g of fluff treatment agent to the drum at a rotation speed of 10r / min and rotating for 50min.

[0072] Comparative Example Comparative Example 1 A method for napping white leather hides, which differs from Example 1 in that, in step S0, an equal amount of potassium persulfate is used to replace cyclohexanone peroxide in the raw materials of the napping agent.

[0073] Comparative Example 2 A method for napping white leather hides, which differs from Example 1 in that, in step S0, an equal amount of cyclohexanone peroxide is used to replace potassium persulfate in the raw materials of the napping agent.

[0074] Comparative Example 3 A method for napping white leather hides, which differs from Example 1 in that step S3 is different.

[0075] Step S3 specifically involves draining the fluid.

[0076] Performance testing The white raw hides of the fur-like leather obtained in step S4 of Examples 1-12 and Comparative Examples 1-3 were taken respectively, and the following performance tests were performed on the white raw hides of the fur-like leather. The test results are shown in Table 2.

[0077] The diameter of hairs on the surface of the suede hides was measured using a wool fineness analyzer. 350 hair diameters were randomly measured from each suede hide, and the mean diameter, standard deviation, and coefficient of variation were calculated. The coefficient of variation, which is the ratio of the standard deviation to the mean diameter, indicates the relative dispersion of hair diameter. A smaller coefficient of variation indicates that the hair diameter is closer to the average value, the hair thickness is more consistent, and the hair thickness is more uniform.

[0078] Table 2 Detection Results Example 1 27.72 6.59 23.77 Example 2 28.96 6.84 23.62 Example 3 28.23 6.70 23.73 Example 4 25.25 5.16 20.44 Example 5 24.83 4.82 19.41 Example 6 26.82 6.16 22.97 Example 7 26.56 5.93 22.33 Example 8 27.57 6.93 25.14 Example 9 30.32 7.08 23.35 Example 10 31.99 7.41 23.16 Example 11 28.55 6.76 23.68 Example 12 29.11 6.86 23.57 Comparative Example 1 33.26 8.79 26.43 Comparative Example 2 33.85 7.78 22.98 Comparative Example 3 34.27 7.85 22.91 As can be seen from Table 2, the napped white leather raw hides obtained by the napping treatment method of this application have low average diameter and coefficient of variation, with an average diameter of 24.83-31.99 μm and a coefficient of variation of 19.41-25.15%. They exhibit the advantages of fine hair, good uniformity of thickness, and good uniformity of thickness distribution. Furthermore, the napped white leather raw hides have a delicate surface, smooth feel, softness, comfort, and natural suppleness, which is conducive to improving the quality of the leather and meeting market demand.

[0079] Example 1 and Comparative Examples 1-2 were compared. Comparative Example 1 used potassium persulfate in its raw material for the flocking agent; Comparative Example 2 used cyclohexanone peroxide in its raw material for the flocking agent; and Example 1 used both potassium persulfate and cyclohexanone peroxide in its raw material for the flocking agent. This demonstrates that simultaneously adding potassium persulfate and cyclohexanone peroxide to the raw material of the flocking agent, and utilizing their synergistic effect, can significantly reduce the average hair diameter and coefficient of variation in the suede of flocked fur leather.

[0080] Comparative Examples 3, 1, and 8-10 were compared. In Comparative Example 3, a single addition of a fluffing agent was added to the raw leather hide; in Example 10, a second addition of a fluffing agent was added; in Example 9, a third addition of a fluffing agent was added; in Example 1, a fourth addition of a fluffing agent was added; and in Example 8, a fifth addition of a fluffing agent was added. It can be seen that as the number of additions of the fluffing agent increases, the average diameter of the hairs on the fluffed raw leather hide gradually decreases and tends to level off. However, the coefficient of variation initially increases and then decreases. This may be due to excessive addition of the fluffing agent, causing excessive damage to the hairs. Adding the fluffing agent two to four times results in superior hair performance on the surface of the fluffed raw leather hide.

[0081] Examples 1, 4, and 6-7 were compared. In Example 1, the raw material for the fluff treatment agent did not contain fluorinated surfactants; in Example 6, the raw material for the fluff treatment agent contained fluorinated surfactants. FS-3100; Example 7: Fluorinated surfactant added to the raw materials of the fluff treatment agent. FS-10; Example 4: Adding sodium sulfonate fluorinated surfactant to the raw materials of the pile treatment agent. It can be seen that adding a fluorinated surfactant to the raw materials of the pile treatment agent, and utilizing its synergistic effect with sodium dioctyl sulfosuccinate, enhances penetration and uniformity, thus improving the effectiveness of the pile treatment agent. In particular, the sodium sulfonate fluorinated surfactant of this application can further reduce the average diameter of hair, improve the uniformity of hair diameter and distribution, and give the fur and leather superior performance and quality.

[0082] It should be noted that the embodiments described above are only for explaining this application and do not constitute any limitation on this application. This application has been described with reference to typical embodiments, but it should be understood that the terms used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to this application within the scope of the claims, and revisions can be made to the invention without departing from the scope and spirit of this application. Although the application described herein relates to specific methods, materials, and embodiments, it does not mean that this application is limited to the specific examples disclosed herein; on the contrary, this application can be extended to all other methods and applications with the same function.

Claims

1. A method for napping suede hides, characterized in that: The main steps include the following: S1. Add raw leather and water to the drum; S2. Add the fluff treatment agent to the drum and rotate for 50-70 minutes. S3. Repeat step S2 at least once to drain the fluid; S4. Add water to the drum, then add a hand-feeling agent and organic acid, rotate for 20-40 minutes, drain the liquid, and complete the napping process to obtain napped white leather raw hide. The fluff treatment agent is mainly made from the following raw materials in parts by weight: 25-35 parts potassium persulfate, 15-25 parts cyclohexanone peroxide, 3-7 parts sodium dioctyl sulfosuccinate, 3-7 parts dipropylene glycol methyl ether, 80-120 parts isopropanol, and 80-120 parts water.

2. The method for napping white raw hides according to claim 1, characterized in that: The weight ratio of the raw leather and water in step S1 is 1:(10-20), and the weight ratio of the raw leather and the fur treatment agent is 1000:(5-7).

3. The method for napping white raw hides according to claim 1, characterized in that: The weight ratio of the raw leather and water in step S4 is 1:(10-20), and the weight ratio of the raw leather, hand feel agent, and organic acid is 1000:(7-9):(7-9).

4. The method for napping white raw hides according to claim 1, characterized in that: The hand feel agent is one or more of the following: hand feel agent LM-3032, hand feel agent XH-A50, hand feel agent XH-A90, hand feel agent AD4003, and hand feel agent AD4005.

5. The method for napping white raw hides according to claim 1, characterized in that: The organic acid is one or more of formic acid, acetic acid, propionic acid, butyric acid, malic acid, and citric acid.

6. The method for napping white raw hides according to claim 1, characterized in that: In step S1, the water temperature is 40-50℃; in step S2, the water temperature is 10-30℃.

7. The method for napping white raw hides according to claim 1, characterized in that: The average diameter of the hairs on the surface of the raw leather is 35-50 μm.

8. The method for napping white raw hides according to claim 1, characterized in that: The raw materials of the fluff treatment agent also include 4-6 parts by weight of fluorinated surfactant.

9. The method for napping white raw hides according to claim 8, characterized in that: The fluorinated surfactant is a sodium sulfonate fluorinated surfactant, which is prepared by the following method: T1. Under the protection of an inert gas at a temperature of 40-60℃, ethanol and p-phenylenediamine are mixed, and then trifluoroethyl acrylate is added dropwise over a period of 50-70 minutes. After the addition is complete, the mixture is stirred for 18-22 hours, and then the ethanol is removed by vacuum distillation to obtain a fluorine-containing intermediate. T2. At a temperature of 70-80℃ and under inert gas protection, acetonitrile and fluorine-containing intermediates are mixed, and then 2,4-butane sulfonyl lactone is added. The mixture is stirred for 18-22 hours, cooled to room temperature, filtered, and washed to obtain sulfonic acid fluorine-containing intermediates. T3. At a temperature of 40-60℃, water and fluorinated sulfonic acid intermediates are mixed, then sodium ethoxide is added, and the mixture is stirred for 8-12 hours. After drying to constant weight, sodium sulfonate fluorinated surfactant is obtained.

10. The method for napping white raw hides according to claim 9, characterized in that: The weight ratio of p-phenylenediamine, trifluoroethyl acrylate, 2,4-butanesulfonyl lactone, and sodium ethoxide is 10:(12-17):(11-14):(5-8).