Anti-yellowing leather fatliquoring agent with modified sulfonated oil as main agent and preparation method thereof

Abstract

The application discloses a yellowing-resistant leather fatliquoring agent taking modified sulfonated oil as a main agent and a preparation method thereof. The leather fatliquoring agent comprises the following components in mass percentage: 30-50% of modified sulfonated oil, 1-5% of ethoxylated alkyl phosphate CEP, 10-20% of coal-based AOS, 1-3% of fatliquoring auxiliary, and 30-50% of water. The leather fatliquoring agent provided by the application has low cost, the modified sulfonated oil as the main agent is introduced with an EO group, the addition of ethylene oxide reduces the raw material cost, and the coal-based AOS has low price. The product has good yellowing resistance. The introduction of the EO group increases the molecular weight of the main agent sulfonated oil, thereby reducing the active groups in the fatliquoring agent under the same addition amount, and the fatliquoring agent is endowed with good yellowing resistance. The product can significantly improve the mechanical strength and softness of a leather product.

Description

Technical Field

[0001] This invention relates to a yellowing-resistant leather fatliquoring agent with modified sulfonated oil as the main agent and its preparation method, belonging to the technical field of leather fatliquoring agents. Background Technology

[0002] my country is a major leather producer, and the leather industry plays a very important role in my country's economic and social development.

[0003] White and light-colored leathers have considerable applications in high-end gloves, footwear, and automotive leather. However, they are inevitably exposed to ultraviolet radiation during use, leading to surface aging and yellowing, significantly affecting their lifespan and appearance. Leather fatliquoring is a crucial step in leather production, involving the treatment of leather with a fatliquoring agent. This allows the leather to absorb a certain amount of oil, imparting specific physical, mechanical, and performance properties. Currently, some fatliquoring agent products with yellowing-resistant properties are available on the domestic market, but these products are expensive and of generally poor quality, failing to meet usage requirements.

[0004] Chinese patent CN113430306A discloses a yellowing-resistant titanium dioxide / fatty acid-based leather fatliquoring agent and its preparation method. Using fatty acids as the main monomer, monoethanolamine as an amidation modifier, and TiO2COOH as a UV shielding agent, a yellowing-resistant TiO2 / fatty acid-based leather fatliquoring agent is prepared by a blending method. This technology solves the problem of surface aging and yellowing that easily occurs in existing leather products during use. By introducing TiO2COOH UV shielding agent into the fatty acid-based fatliquoring agent through blending, a TiO2 / fatty acid-based leather fatliquoring agent with both good mechanical properties and yellowing resistance is finally obtained. The yellowing resistance level of the raw leather after fatliquoring can reach level 4-5.

[0005] Chinese patent CN110564901A discloses a succinate-sulfonated Sichuan pepper seed oil / nano-perovskite oxide composite anti-yellowing fatliquoring agent and its preparation method. The method involves preparing zirconium-aluminum dual-doped perovskite oxides using a sol-gel method and incorporating them into a succinate-sulfonated rapeseed oil matrix to obtain the succinate-sulfonated Sichuan pepper seed oil / nano-perovskite oxide composite anti-yellowing fatliquoring agent. The zirconium-aluminum dual-doped perovskite oxides possess excellent UV absorption capabilities, imparting high anti-yellowing properties to fatliquoring leather. Due to the tanning properties of this oxide and the presence of cationic vacancies, it can simultaneously bind with leather collagen and anionic fatliquoring agents, significantly increasing the absorption rate of the prepared composite fatliquoring agent. After fatliquoring, the leather sample exhibits a smooth, soft feel, good fullness, and significantly improved anti-yellowing properties.

[0006] The anti-yellowing fatliquoring agents reported in the aforementioned patent documents all use metal oxides as UV shielding agents, which have complex production processes, high costs, and are difficult to industrialize. Summary of the Invention

[0007] In view of this, the present invention provides a yellowing-resistant leather fatliquoring agent compounded with modified sulfonated oil as raw material and its preparation method, which can meet the requirements of yellowing resistance and low cost of leather fatliquoring agents, and can effectively improve the softness and mechanical strength of the leather after fatliquoring.

[0008] This application uses alkoxylated modified sulfonated oil as the main agent to obtain a yellowing-resistant leather fatliquoring agent through compounding. All raw materials can be produced using existing large-scale industrial equipment, and the product meets the requirements of yellowing resistance and low cost. Sulfonated oil is a commonly used leather fatliquoring auxiliary agent, with common raw materials including rapeseed oil and castor oil. When sulfonated oil is used for leather fatliquoring, the finished leather is prone to yellowing mainly due to the presence of a large number of unstable double bonds in the oil structure. Inserting EO groups into the raw oil can increase the water solubility of the raw material, reduce coking during sulfonation, and solve the problem of poor product flowability. It can also increase the molecular weight of the raw material and reduce its hydroxyl value, i.e., reduce the number of double bonds per unit mass of raw material. For modified sulfonated castor oil, SO3 can react with double bonds, greatly reducing the double bond content in the product. Therefore, it can effectively alleviate the yellowing problem of leather caused by the introduction of vegetable oil fatliquoring agents. Furthermore, the sulfonated oil obtained by SO3 membrane sulfonation retains its trimer structure to the greatest extent, resulting in good lubrication. The introduction of EO groups increases the product's water solubility, allowing it to form fine and stable emulsions with water. This emulsion has good penetration properties and can be effectively absorbed by the leather, surrounding the individual fibers within the leather and increasing inter-fiber mobility. This makes the fatliquoring leather softer, fuller, and stronger. Coal-based AOS is obtained from a mixture of alkanes / olefins in Fischer-Tropsch synthetic oil through sulfonation, neutralization, and hydrolysis. It contains olefin sulfonates and unreacted alkanes. These alkanes can act as mineral oil components, improving the softness of the fatliquoring leather. Simultaneously, the mineral oil structure is stable and not easily decomposed, resulting in odorless leather after fatliquoring. Due to the consistent carbon chain distribution, the generated olefin sulfonates have excellent emulsifying effects on unreacted alkanes. Therefore, when coal-based AOS is compounded with modified sulfonated oil, no additional emulsifier is needed to obtain a stable leather fatliquoring agent product. The P=O bond in ethoxylated alkyl phosphate has a strong complexing ability with chromium in leather, which is beneficial for the leather to maintain its softness, fullness and elasticity for a long time after fatliquoring; when compounded with modified sulfonated oil, it can further improve the softness of leather.

[0009] This invention provides a yellowing-resistant leather fatliquoring agent with modified sulfonated oil as the main agent, comprising the following components by mass percentage: 30-50% modified sulfonated oil, 1-5% ethoxylated alkyl phosphate (CEP), 10-20% coal-based AOS, 1-3% fatliquoring aid, and 30-50% water.

[0010] The modified sulfonated oil described above is obtained by ethoxylation of oil followed by sulfonation and neutralization. The oil can be rapeseed oil or castor oil. The preparation process is as follows:

[0011] The oil and Mg-Al composite insertion ethoxylation catalyst were placed in a high-pressure reactor. After purging with nitrogen to remove water, the reactor was heated to 150-200℃, the rotation speed was controlled at 500 r / min, and ethylene oxide was introduced at a pressure of 0.3-0.4 MPa. After the addition was completed, the temperature in the reactor was maintained until the pressure remained constant. After cooling, the sample was taken out to obtain the oil ethoxylate.

[0012] The obtained ethoxylated oil is reacted in an SO3 membrane sulfonation device to prepare modified sulfonated oil, which is then neutralized to obtain the corresponding sulfonate. During the sulfonation process, the SO3 / air volume ratio is 4.0–7.0%. The molar ratio of SO3 to ethoxylated oil is adjusted to obtain modified sulfonated oil with an SO3 binding content of 1%–9%. After neutralization with sodium hydroxide aqueous solution and adjustment of pH to 6–7, the corresponding modified sulfonated oil is obtained.

[0013] As described above, ethoxylated alkyl phosphates (C x E y PM), with a carbon chain length x of 8~14, an EO number y of 2~5, and M being the type of neutralizing salt, which can be one of Na, K or NH4;

[0014] The coal-based AOS described above is a mixture of coal-based alkanes and olefins (C... 14~16 The fraction is obtained through sulfonation, neutralization, and hydrolysis, and contains 40-60% C. 14~16 Alkanes are prepared as follows:

[0015] (1) Sulfonation

[0016] The coal-based alkane / olefin mixture and the sulfur trioxide / air mixture both enter the sulfonation reactor from the top of the membrane sulfonator. They flow downstream and undergo a sulfonation reaction. The reaction products leave from the bottom of the membrane sulfonator and enter the gas-liquid separator to be separated into a liquid phase and a gas phase. The gas phase is the sulfonation tail gas, and the liquid phase is a mixture of alkane and olefin sulfonation products.

[0017] The sulfonation process conditions are as follows: feed temperature of coal-based alkane / olefin mixture is 15-30℃, feed rate of organic matter per tube is 30-40kg / tube, cooling water temperature of sulfonator jacket is 15-40℃, molar ratio of olefin to SO3 in raw material is 1:1.0-1.2, and SO3 gas volume concentration in sulfur trioxide / air mixture is 3-7%.

[0018] (2) Neutralization

[0019] The alkenyl sulfonic acid is neutralized with 2 to 3 times the theoretical neutralization value of sodium hydroxide to obtain alkenyl sulfonate.

[0020] (3) Hydrolysis

[0021] The neutralized product was added to a high-pressure reactor, and the hydrolysis temperature was controlled at 120~170℃ for 2~5h to obtain coal-based AOS.

[0022] The aforementioned fatliquoring aid is a filler, and can be a filler-type fatliquoring agent SDF.

[0023] The present invention also provides a method for preparing the above-mentioned yellowing-resistant leather fatliquoring agent with modified sulfonated oil as the main agent. After mixing water, ethoxylated alkyl phosphate (CEP) and filler-type fatliquoring agent SDF, the modified sulfonated oil is added, and after stirring evenly, coal-based AOS is added and stirred evenly to obtain the yellowing-resistant leather fatliquoring agent.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) Low cost: EO groups are introduced into the modified sulfonated oil of the main agent, the addition of ethylene oxide reduces the cost of raw materials, and the price of coal-based AOS is low;

[0026] (2) The formula is simple. Coal-based AOS is obtained by direct sulfonation of a mixture of Fischer-Tropsch alkanes and olefins. On the one hand, it reduces the cost of AOS with emulsifying effect, and on the other hand, it directly adds alkanes to the formula. Moreover, due to the similar carbon chain structure, coal-based AOS can exist directly in a stable emulsion form without the need to add emulsifiers.

[0027] (3) Leather fatliquoring agents have good resistance to yellowing. The introduction of EO groups increases the molecular weight of the main sulfonated oil, thereby reducing the active groups in the fatliquoring agent at the same addition amount, thus giving the fatliquoring agent good resistance to yellowing.

[0028] (4) Leather fatliquoring agents can significantly improve the mechanical strength of leather products;

[0029] (5) Leather fatliquoring agents can significantly improve the softness of leather products. Attached Figure Description

[0030] Figure 1 The color change of commercially available products after treating leather with fatliquoring agents and then irradiating it with UV light at 60°C for 48 hours is shown in the graph.

[0031] Figure 2 The image shows the color change of leather treated with the product of Example 1 as a fatliquoring agent before and after UV irradiation at 60°C for 48 hours. Detailed Implementation

[0032] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention. Example 1

[0033] The preparation process of ethoxylated modified sulfonated rapeseed oil is as follows:

[0034] Rapeseed oil and Mg-Al composite insertion ethoxylation catalyst were placed in a high-pressure reactor at a mass ratio of 100:0.5. After purging the reactor with nitrogen to remove water, the reactor was heated to 150°C, the rotation speed was controlled at 500 r / min, ethylene oxide was introduced, and the system pressure was controlled at 0.3 MPa. After the addition was completed, the temperature in the reactor was maintained until the pressure remained constant. After cooling, the sample was taken out to obtain modified rapeseed oil.

[0035] The modified rapeseed oil was reacted in an SO3 membrane sulfonation device to prepare modified sulfonated oil, which was then neutralized to obtain the corresponding sulfonate. During the sulfonation process, the SO3 / air volume ratio was 4.0%. The molar ratio of SO3 to modified rapeseed oil was adjusted to obtain modified sulfonated oil with an SO3 binding content of 4%. After neutralization with sodium hydroxide aqueous solution and adjustment of pH to 7, the corresponding modified sulfonated oil was obtained.

[0036] The coal-based AOS preparation process is as follows:

[0037] (1) Sulfonation

[0038] The Fischer-Tropsch C14-16 fraction alkane / olefin mixture and sulfur trioxide / air mixture are both introduced into the sulfonation reactor from the top of the membrane sulfonator. The two flow downstream and undergo sulfonation. The reaction products leave from the bottom of the membrane sulfonator and enter the gas-liquid separator to be separated into liquid and gas phases. The gas phase is the sulfonation tail gas, and the liquid phase is a mixture of alkane and olefin sulfonation products.

[0039] The sulfonation process conditions are as follows: organic feed temperature 15℃, organic feed rate per tube 30kg / tube, sulfonator jacket cooling water temperature 15℃, olefin to SO3 molar ratio in the raw material 1:1.0, and SO3 gas volume concentration in the sulfur trioxide / air mixture 3%.

[0040] (2) Neutralization

[0041] The alkenylsulfonic acid was neutralized with twice the amount of sodium hydroxide, according to the theoretical neutralization value, to obtain alkenylsulfonate.

[0042] (3) Hydrolysis

[0043] The neutralized product was added to a high-pressure reactor, and the hydrolysis temperature was controlled at 120℃ for 5 hours to obtain coal-based AOS.

[0044] The raw materials are prepared in the following mass ratio: 30% ethoxylated modified sulfonated rapeseed oil, and 30% ethoxylated alkyl phosphate (C 8 E 5A leather fatliquoring agent resistant to yellowing was prepared by mixing 5% P-Na, 15% coal-based AOS, 3% fatliquoring agent SDF, and 47% water. Example 2

[0045] The preparation process of ethoxylated modified sulfonated castor oil is as follows:

[0046] Castor oil and Mg-Al composite insertion ethoxylation catalyst were placed in a high-pressure reactor at a mass ratio of 100:0.5. After purging the reactor with nitrogen to remove water, the reactor was heated to 180°C, the rotation speed was controlled at 500 r / min, ethylene oxide was introduced, and the system pressure was controlled at 0.4 MPa. After the addition was completed, the temperature in the reactor was maintained until the pressure remained constant. After cooling, the sample was taken out to obtain modified castor oil.

[0047] The modified castor oil was reacted in an SO3 membrane sulfonation unit to prepare modified sulfonated oil, which was then neutralized to obtain the corresponding sulfonate. During the sulfonation process, the SO3 / air volume ratio was 5.0%. The molar ratio of SO3 to modified castor oil was adjusted to obtain modified sulfonated oil with an SO3 binding content of 1%. After neutralization with sodium hydroxide aqueous solution and adjustment of pH to 6, the corresponding modified sulfonated oil was obtained.

[0048] The coal-based AOS preparation process is as follows:

[0049] (1) Sulfonation

[0050] The Fischer-Tropsch C14-16 fraction alkane / olefin mixture and sulfur trioxide / air mixture are both introduced into the sulfonation reactor from the top of the membrane sulfonator. The two flow downstream and undergo sulfonation. The reaction products leave from the bottom of the membrane sulfonator and enter the gas-liquid separator to be separated into liquid and gas phases. The gas phase is the sulfonation tail gas, and the liquid phase is a mixture of alkane and olefin sulfonation products.

[0051] The sulfonation process conditions are as follows: organic feed temperature 25℃, organic feed rate per tube 35kg / tube, sulfonator jacket cooling water temperature 20℃, olefin to SO3 molar ratio in the raw material 1:1.1, and SO3 gas volume concentration in the sulfur trioxide / air mixture 5%.

[0052] (2) Neutralization

[0053] The alkenylsulfonic acid was neutralized with 2.5 times the theoretical neutralization value of sodium hydroxide to obtain alkenylsulfonate.

[0054] (3) Hydrolysis

[0055] The neutralized product was added to a high-pressure reactor, and the hydrolysis temperature was controlled at 150℃ for 3 hours to obtain coal-based AOS.

[0056] The raw materials are prepared in the following mass ratio: 50% ethoxylated modified sulfonated castor oil, and 50% ethoxylated alkyl phosphate (C 10 E 3 A leather fatliquoring agent resistant to yellowing was prepared by mixing 1% PK, 10% coal-based AOS, 1% fatliquoring agent SDF, and 38% water. Example 3

[0057] The preparation process of ethoxylated modified sulfonated castor oil is as follows:

[0058] Castor oil and Mg-Al composite insertion ethoxylation catalyst were placed in a high-pressure reactor at a mass ratio of 100:0.5. After purging the reactor with nitrogen to remove water, the reactor was heated to 200°C and the rotation speed was controlled at 500 r / min. Ethylene oxide was introduced at 0.4 MPa. After the addition was completed, the temperature in the reactor was maintained until the pressure remained constant. After cooling, the sample was taken out to obtain the ethoxylated oil.

[0059] The obtained ethoxylated oil was reacted in an SO3 membrane sulfonation device to prepare modified sulfonated oil, which was then neutralized to obtain the corresponding sulfonate. During the sulfonation process, the SO3 / air volume ratio was 7.0%. The molar ratio of SO3 to ethoxylated oil was adjusted to obtain modified sulfonated oil with an SO3 binding content of 9%. After neutralization with sodium hydroxide aqueous solution and adjustment of pH to 7, the corresponding modified sulfonated oil was obtained.

[0060] The preparation process of coal-based AOS is as follows:

[0061] (1) Sulfonation

[0062] The coal-based alkane / olefin mixture and the sulfur trioxide / air mixture both enter the sulfonation reactor from the top of the membrane sulfonator. They flow downstream and undergo a sulfonation reaction. The reaction products leave from the bottom of the membrane sulfonator and enter the gas-liquid separator to be separated into a liquid phase and a gas phase. The gas phase is the sulfonation tail gas, and the liquid phase is a mixture of alkane and olefin sulfonation products.

[0063] The sulfonation process conditions are as follows: organic feed temperature 30℃, organic feed rate per tube 40kg / tube, sulfonator jacket cooling water temperature 40℃, olefin to SO3 molar ratio in the raw material 1:1.2, and SO3 gas volume concentration in the sulfur trioxide / air mixture 3%.

[0064] (2) Neutralization

[0065] The alkenylsulfonic acid was neutralized with three times the theoretical neutralization value of sodium hydroxide to obtain alkenylsulfonate.

[0066] (3) Hydrolysis

[0067] The neutralized product was added to a high-pressure reactor, and the hydrolysis temperature was controlled at 170℃ for 2 hours to obtain coal-based AOS.

[0068] The raw materials are prepared in the following mass ratio: 40% ethoxylated modified sulfonated castor oil, and 40% ethoxylated alkyl phosphate (C 1214 E 2 P-NH 4 A leather fatliquoring agent resistant to yellowing was prepared by mixing 3%, coal-based AOS 20%, fatliquoring agent SDF 2%, and water 35%. Example 4

[0069] The preparation process of ethoxylated modified sulfonated rapeseed oil is as follows:

[0070] Rapeseed oil and Mg-Al composite insertion ethoxylation catalyst were placed in a high-pressure reactor at a mass ratio of 100:0.5. After purging the reactor with nitrogen to remove water, the reactor was heated to 160°C, the rotation speed was controlled at 500 r / min, ethylene oxide was introduced, and the system pressure was controlled at 0.4 MPa. After the addition was completed, the temperature in the reactor was maintained until the pressure remained constant. After cooling, the sample was taken out to obtain modified rapeseed oil.

[0071] The modified rapeseed oil was reacted in an SO3 membrane sulfonation device to prepare modified sulfonated oil, which was then neutralized to obtain the corresponding sulfonate. During the sulfonation process, the SO3 / air volume ratio was 5.0%. The molar ratio of SO3 to modified rapeseed oil was adjusted to obtain modified sulfonated oil with an SO3 binding content of 5%. After neutralization with sodium hydroxide aqueous solution and adjustment of pH to 7, the corresponding modified sulfonated oil was obtained.

[0072] The coal-based AOS preparation process is as follows:

[0073] (1) Sulfonation

[0074] The Fischer-Tropsch C14-16 fraction alkane / olefin mixture and sulfur trioxide / air mixture are both introduced into the sulfonation reactor from the top of the membrane sulfonator. The two flow downstream and undergo sulfonation. The reaction products leave from the bottom of the membrane sulfonator and enter the gas-liquid separator to be separated into liquid and gas phases. The gas phase is the sulfonation tail gas, and the liquid phase is a mixture of alkane and olefin sulfonation products.

[0075] The sulfonation process conditions are as follows: organic feed temperature 20℃, organic feed rate per tube 30kg / tube, sulfonator jacket cooling water temperature 30℃, olefin to SO3 molar ratio in the raw material 1:1.1, and SO3 gas volume concentration in the sulfur trioxide / air mixture 4%.

[0076] (2) Neutralization

[0077] The alkenylsulfonic acid was neutralized with 2.5 times the theoretical neutralization value of sodium hydroxide to obtain alkenylsulfonate.

[0078] (3) Hydrolysis

[0079] The neutralized product was added to a high-pressure reactor, and the hydrolysis temperature was controlled at 140℃ for 4 hours to obtain coal-based AOS.

[0080] The raw materials are prepared in the following mass ratio: 40% ethoxylated modified sulfonated rapeseed oil, and 40% ethoxylated alkyl phosphate (C 8 E 5 A leather fatliquoring agent resistant to yellowing was prepared by mixing 5% P-Na, 10% coal-based AOS, 3% fatliquoring agent SDF, and 42% water.

[0081] Performance testing:

[0082] The leather fatliquoring performance was evaluated using wet blue bovine leather. The fatliquoring agent dosage was 12%, the fatliquoring temperature was 50℃, and the leather softness, mechanical properties, and color difference ΔE before and after yellowing were measured after fatliquoring.

[0083] Tensile strength and elongation at break were determined using a universal testing machine (GT-U55, Dongguan Gotech Testing Machines Co., Ltd.) and standard procedures according to GB / T 17928-1999. Tear strength was determined according to QB / T 39371-2020. Softness was measured using a softness tester (GT303, Dongguan Gotech Testing Machines Co., Ltd.) according to standard ISO 17235:2015. The color difference ΔE before and after yellowing was calculated using an LY-605A yellowing resistance tester after UV treatment at 60℃ for 48 hours. Better yellowing resistance resulted in a smaller ΔE value.

[0084] The evaluation results of the leather fatliquoring performance of commercially available products and samples from Examples 1-3 are shown in Table 1.

[0085] Table 1

[0086]

[0087] Note: Commercially available products are sourced from Shandong Yousuo.

[0088] As shown in Table 1, the leather treated in Examples 1-3 of the present invention exhibits higher softness, tear strength, elongation at break, and tensile strength compared to commercially available products. The leather fatliquoring agent provided by this invention, by inserting EO groups into the raw material oil, can increase the water solubility of the raw material, reduce coking during sulfonation, and solve the problem of poor product flowability. It can also increase the molecular weight of the raw material and reduce its hydroxyl value, i.e., reduce the number of double bonds per unit mass of raw material. For modified sulfonated castor oil, SO3 can react with the double bonds, significantly reducing the double bond content in the product, thus effectively alleviating the yellowing problem of leather caused by the introduction of vegetable oil fatliquoring agents. For modified sulfonated rapeseed oil, the introduction of EO groups avoids the coking problem in the current sulfonated rapeseed oil production process, avoids product quality fluctuations caused by frequent equipment shutdowns for cleaning, and effectively reduces product color, minimizing the influence of the sulfonated oil fatliquoring agent's own color on the color of the leather after fatliquoring treatment. Furthermore, the sulfonated oil obtained by SO3 membrane sulfonation retains its trimer structure to the greatest extent, resulting in good lubrication. The introduction of EO groups increases the water solubility of the product, allowing it to form a fine and stable emulsion with water. This emulsion has good penetration properties and can be effectively absorbed by the leather, surrounding each fiber inside the leather with sulfonated oil, increasing the mobility between fibers, and making the fatliquoring leather softer, fuller, and stronger. Coal-based AOS, when compounded with modified sulfonated oil, can produce a stable leather fatliquoring agent product without the need for additional emulsifiers. The P=O bond in ethoxylated alkyl phosphate has a strong complexing ability with chromium in the leather, which is beneficial for the long-term maintenance of softness, fullness, and elasticity of the fatliquoring leather. When compounded with modified sulfonated oil, it can further improve the softness of the leather.

[0089] Appendix Figure 1 , 2 The images show the color changes of commercially available products and leather treated with the fatliquoring agent of Example 1 before and after 48 hours of UV irradiation at 60°C (the background of the images is leather that has not undergone yellowing testing). It can be seen that the degree of yellowing of the leather treated with the fatliquoring agent of Example 1 after UV irradiation is significantly lower than that of commercially available products.

[0090] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A yellowing-resistant type of leather fatliquoring agent using a modified sulfonated oil as a main agent, characterized by: consists of the following components by mass percent: modified sulfonated oil 30-50%, ethoxylated alkyl phosphate C x EO y P-M 1-5%, coal-based AOS 10-20%, fatting aid 1-3%, water 30-50%; The modified sulfonated oil is obtained by sulfonation and neutralization of the oil ethoxylate, wherein the oil is rapeseed oil or castor oil, and the preparation process is as follows: The oil and Mg-Al composite plug-in type ethoxylation catalyst are placed in a high-pressure reactor, and after water is removed by nitrogen blowing, the reactor is heated to 150-200 DEG C, the rotating speed is controlled to 500 r / min, the ethylene oxide is introduced, the pressure is 0.3-0.4 MPa, after the feeding is completed, the temperature in the reactor is maintained until the pressure is constant, and then the sample is taken out after cooling to obtain the oil ethoxylate; The obtained oil ethoxylate is reacted by SO3 membrane sulfonation device to prepare the modified sulfonated oil, and then the corresponding sulfonate is obtained by neutralization; in the sulfonation process, the SO3 / air volume ratio is 4.0-7.0%, the SO3 / oil ethoxylate molar ratio is adjusted, the modified sulfonated oil with SO3 combination amount of 1%-9% is obtained, and the corresponding modified sulfonated oil is obtained by neutralization with sodium hydroxide solution, adjusting pH 6-7; The ethoxylated alkyl phosphate salt C x EO y The carbon chain length x of P-M is 8-14, the number of EO y is 2-5, M is a neutralized salt type, and M is one of Na, K, or NH4. The coal-based AOS is a coal-based alkane / alkene mixture C 14~16 The distillate section, after sulfonation, neutralization and hydrolysis, contains 40-60% C 14~16 Alkanes are prepared as follows: (1) Sulfonation The coal-based alkane / alkene mixture and the sulfur trioxide / air mixed gas are introduced from the upper part of the membrane sulfonator into the sulfonation reactor, and the two are down-flowed and sulfonated, the reaction product is discharged from the lower part of the membrane sulfonator into the gas-liquid separator to separate into liquid phase and gas phase, wherein the gas phase is sulfonation tail gas, and the liquid phase is a mixture of alkane and alkene sulfonation products; The sulfonation process conditions are as follows: the coal-based alkane / alkene mixture feed temperature is 15-30 DEG C, the organic matter single pipe feed amount is 30-40 kg / pipeline, the sulfonator jacket cooling water temperature is 15-40 DEG C, the molar ratio of alkene to SO3 in the raw material is 1:1.0-1.2, and the SO3 gas volume concentration in the sulfur trioxide / air mixed gas is 3-7%; (2) Neutralization The alkyl sulfonic acid is neutralized with 2-3 times the theoretical neutralization value of sodium hydroxide to obtain an alkyl sulfonate; (3) Hydrolysis The neutralized product is added to a high-pressure reactor, the hydrolysis temperature is controlled to 120-170 DEG C, and the hydrolysis time is 2-5 h to obtain a coal-based AOS.

2. The anti-yellowing type leather fat-liquoring agent with modified sulfonated oil as a main agent according to claim 1, characterized in that: The fatting aid is a filling type fatting agent SDF.

3. A method for preparing the anti-yellowing type of leather fatliquoring agent using the modified sulfonated oil as the main agent according to any one of claims 1 to 2, characterized in that: Water and ethoxylated alkyl phosphate C x EO y After mixing water, P-M and fat-liquoring assistant, add modified sulfonated oil, after stirring evenly, add coal-based AOS, stir evenly, and then the anti-yellowing type leather fat-liquoring agent is obtained.

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