Polymer waterproofing fat liquor and method for preparing the same

Abstract

This invention belongs to the field of fatliquoring agent preparation technology, and particularly relates to a polymer waterproof fatliquoring agent and its preparation method. The fatliquoring agent is obtained by polymerization of raw materials including octadecyl acrylate, octadecyl methacrylate, hexadecene, acrylic acid, a cyclodextrin-long-chain acrylate inclusion complex dispersion, an antibacterial functional monomer, and an antioxidant auxiliary agent. By employing a "starved droplet method" and a post-initiator, and utilizing 2-hydroxypropyl-β-cyclodextrin inclusion, the solubility of the long-chain acrylate is effectively improved, achieving effective copolymerization. The prepared fatliquoring agent exhibits good hydrophobicity, softness, and resistance to yellowing.

Description

Technical Field

[0001] This invention belongs to the field of fatliquoring agent preparation technology, specifically relating to a polymer waterproof fatliquoring agent and its preparation method. Background Technology

[0002] my country is a major leather producer, and in recent years, the leather industry has developed into a distinctive industry, playing a vital role in national economic development. With increasing environmental awareness and the influx of foreign products, domestic leather chemical production must rely on technological innovation, continuous product structure adjustment, and improved product quality to enhance competitiveness in domestic and international markets. Under the inevitable trend of cleaner leather production, increasing the development and use of green chemicals is fundamental to achieving cleaner leather processing. Fatliquoring is a key process in leather production, and fatliquoring agents are important leather chemicals, as well as the most widely used leather chemical material, significantly impacting the properties of the finished leather. Under certain conditions, fatliquoring agents can penetrate between the collagen fibers of leather, acting as lubricants and plasticizers, facilitating the movement of collagen fiber molecular chains and segments, thus giving the finished leather softness, moisture, water resistance, sun protection, and elasticity. Among the essential materials for retanning processes, acrylic retanning fatliquoring agents have seen rapid development in recent years. With advancements in synthetic technology, some varieties have now replaced imported materials in China's leather industry, improving the quality of finished leather and reducing costs. With technological advancements, multifunctional synthetic materials possessing retanning, fatliquoring, and waterproofing properties have become important tanning auxiliaries. Acrylic retanning and fatliquoring agents are high-molecular-weight leather tanning auxiliaries whose molecular structure contains both hydrophilic carboxyl groups and hydrophobic long-chain hydrocarbon groups, with the hydrophobic long-chain hydrocarbon groups comprising approximately 20% to 80% by mass. This treatment method has no significant impact on the water-based finishing, water permeability, and breathability of the leather. Therefore, it is suitable for producing various types of leather, especially waterproof and washable leather.

[0003] Chinese Patent CN112126025B discloses a method for preparing a benign polymer retanning and fatliquoring agent. The agent is prepared using maleic anhydride, natural oils, acrylic acid, long-chain alkyl acrylate monomers, vinylimidazole ionic liquids, emulsifiers, and initiators as raw materials. By introducing vinylimidazole ionic liquids into the polymerization system, the polymerization reaction can proceed without solvent participation, reducing environmental pollution during production and use. Furthermore, the introduction of positively charged groups by the vinylimidazole ionic liquids into the retanning and fatliquoring agent increases the positive charge of the leather after retanning and fatliquoring, which is beneficial for dye uptake. However, existing fatliquoring agents lack sufficient water resistance and stability, and have limited functionality. Therefore, the preparation of a fatliquoring agent with high copolymerization rate, multifunctionality, and high stability has become a research focus. Summary of the Invention

[0004] To address at least one of the above problems, the present invention provides a method for preparing a polymer waterproofing and fatliquoring agent, comprising the following steps: S100: A cyclodextrin-long-chain acrylate inclusion complex dispersion was prepared using raw materials including 2-hydroxypropyl-β-cyclodextrin, octadecyl acrylate, and octadecyl methacrylate. S200: Add ethylene glycol monobutyl ether and viscosity adjuster to the reactor, mix well, and then purge with inert gas to replace the air. Then add cyclodextrin-acrylic acid long-chain ester inclusion complex dispersion, hexadecene, acrylic acid, antibacterial functional monomer, and antioxidant. Heat to 65-75℃, and add 20%-50% of the required amount of sodium alkyl sulfate polymerization aid while stirring. After stirring evenly, add 80%-90% of the required amount of azo initiator. After the addition is complete, raise the temperature to 80-85℃ and keep it at that temperature for 1-3 hours. Then add the remaining sodium alkyl sulfate polymerization aid and azo initiator, and continue to keep it at that temperature for 1.5-2.5 hours. Add an interface modifier, lower the temperature to 70-75℃ and keep it at that temperature for 1-3 hours to obtain the blend. S300. Reduce the reactor temperature to 55-60℃, add a neutralizing agent, and after the addition is complete, reduce the temperature to 45-50℃ and keep it warm for 1-2 hours to obtain the fatliquoring agent.

[0005] Further, step S100 specifically involves dissolving 2-hydroxypropyl-β-cyclodextrin in deionized water, heating it to 50-55°C, adding octadecyl acrylate and octadecyl methacrylate while stirring, and stirring at a constant temperature for 2-3 hours to obtain a cyclodextrin-long-chain acrylic acid ester inclusion complex dispersion.

[0006] Furthermore, the mass ratio of 2-hydroxypropyl-β-cyclodextrin, octadecyl acrylate, and octadecyl methacrylate is 0.15-0.25:0.2-0.6:0.15-0.3.

[0007] Furthermore, the viscosity modifier is a mixture of fatty acid methyl ester and mineral oil.

[0008] Furthermore, the preparation method of the antioxidant auxiliaries is as follows: A1. Add anhydrous dichloromethane and α-tocopherol to the reactor, mix well, and then lower the temperature to 0-5℃. Under an inert atmosphere, add triethylamine and methacrylamide chloride. After the addition is complete, stir at low temperature for 3-5 hours. After the reaction is complete, add deionized water to wash, collect the organic phase, and obtain the α-tocopherol derivative after drying and vacuum distillation. A2. Add 2-(diethylamino)ethyl acrylate and dodecanethiol to anhydrous ethanol, raise the temperature to 50-60°C while stirring, and add dropwise an ethanol solution of azobisisobutyronitrile and an ethanol solution of α-tocopherol derivative under an inert atmosphere. After the addition is complete, raise the temperature to 65-75°C and stir at a constant temperature for 8-12 hours. After the reaction is complete, cool to room temperature, pour into ice-cold ether, let stand for 30-50 minutes, collect the precipitate, and obtain the antioxidant auxiliary agent by washing and drying.

[0009] Furthermore, the preparation method of the interface modifier is as follows: triethanolamine is added to the reactor and then phosphoric acid is slowly added. After stirring the reaction for 1.5-2.5 hours, the mixture is cooled to room temperature to obtain the interface modifier.

[0010] Further, step S300 specifically involves: after lowering the reactor temperature to 55-60℃, adding a neutralizing agent dropwise, pausing for 1-2 minutes after every 3-5 minutes of dropwise addition, controlling the reactor temperature to ≤65℃, stopping the addition of the neutralizing agent when the system pH reaches 6.5-7.5, then lowering the temperature to 45-50℃ and maintaining the temperature for 1-2 hours to obtain the fatliquoring agent.

[0011] Furthermore, the neutralizing agent is a mixture of sodium hydroxide and triethanolamine in a weight ratio of 1:0.25-0.45.

[0012] A polymer waterproofing and fatliquoring agent is prepared by the preparation method of a polymer waterproofing and fatliquoring agent described in any of the above technical solutions.

[0013] The present invention has the following beneficial effects: Fatliquoring agents are obtained through polymerization reactions using octadecyl acrylate, octadecyl methacrylate, hexadecene, acrylic acid, a dispersion of cyclodextrin-long-chain acrylic acid ester inclusion complex, antibacterial functional monomers, and antioxidant auxiliaries. Due to significant differences in the hydrophilicity / hydrophobicity, steric hindrance, and copolymerization rate of the monomers used, copolymerization is difficult to achieve. This invention utilizes a "starved drop addition" method and a post-initiator, and through inclusion with 2-hydroxypropyl-β-cyclodextrin, effectively improves the solubility of the long-chain acrylic acid ester, achieving effective copolymerization. The successful introduction of hydrophilic carboxyl groups and hydrophobic long-chain groups into the molecular structure significantly improves the water solubility, dispersibility, and permeability of the fatliquoring agent. The special structure imparts appropriate hydrophobicity to the fatliquoringed leather. The synergistic effect of the various substances enables the formation of hydrogen bonds and other interactions between the fatliquoring agent and leather fibers, achieving a strong bond between the fatliquoring agent and leather fibers and preventing defects such as "white bloom" and oil seepage. Detailed Implementation

[0014] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0015] Leather fatliquoring agents are core materials for improving the softness and fullness of leather. Among them, acrylate polymer fatliquoring agents are widely used because they have both retanning and fatliquoring functions. However, existing technologies have problems such as long-chain acrylates having long carbon chains and strong hydrophobicity, resulting in low solubility in aqueous polymerization systems and easy aggregation, leading to uneven copolymerization. Based on this, the present invention provides a method for preparing a polymer waterproof fatliquoring agent, including the following steps: S100: A cyclodextrin-long-chain acrylate inclusion complex dispersion was prepared using raw materials including 2-hydroxypropyl-β-cyclodextrin, octadecyl acrylate, and octadecyl methacrylate. S200: Add ethylene glycol monobutyl ether and viscosity adjuster to the reactor, mix well, and then purge with inert gas to replace the air. Then add cyclodextrin-acrylic acid long-chain ester inclusion complex dispersion, hexadecene, acrylic acid, antibacterial functional monomer, and antioxidant. Heat to 65-75℃, and add 20%-50% of the required amount of sodium alkyl sulfate polymerization aid while stirring. After stirring evenly, add 80%-90% of the required amount of azo initiator. After the addition is complete, raise the temperature to 80-85℃ and keep it at that temperature for 1-3 hours. Then add the remaining sodium alkyl sulfate polymerization aid and azo initiator, and continue to keep it at that temperature for 1.5-2.5 hours. Add an interface modifier, lower the temperature to 70-75℃ and keep it at that temperature for 1-3 hours to obtain the blend. S300. Reduce the reactor temperature to 55-60℃, add a neutralizing agent, and after the addition is complete, reduce the temperature to 45-50℃ and keep it warm for 1-2 hours to obtain the fatliquoring agent.

[0016] Specifically, step S100 involves dissolving 2-hydroxypropyl-β-cyclodextrin in deionized water, heating the solution to 50-55°C, adding octadecyl acrylate and octadecyl methacrylate while stirring, and stirring at a constant temperature for 2-3 hours to obtain a cyclodextrin-long-chain acrylic acid ester inclusion complex dispersion.

[0017] In this step, the mass ratio of 2-hydroxypropyl-β-cyclodextrin, octadecyl acrylate, and octadecyl methacrylate is 0.15-0.25:0.2-0.6:0.15-0.3; the amount of deionized water used is 4-8 times the mass of 2-hydroxypropyl-β-cyclodextrin. 2-hydroxypropyl-β-cyclodextrin has a hydrophobic cavity structure, which matches the hydrophobic carbon chains of octadecyl acrylate and octadecyl methacrylate, forming a stable inclusion complex through van der Waals forces and hydrophobic interactions. Simultaneously, the hydroxypropyl groups on the surface of the 2-hydroxypropyl-β-cyclodextrin molecule are hydrophilic, enabling the inclusion complex to be stably dispersed in the aqueous phase, which is beneficial for the dispersion of long-chain monomers.

[0018] The viscosity modifier is a mixture of fatty acid methyl esters and mineral oil. Specifically, the fatty acid methyl esters are a mixture of methyl hexanoate, methyl octanoate, and methyl decanoate in a mass ratio of 1-2:2-3:4-5; the short-chain structure reduces inter-monomer interfacial tension and increases miscibility with cyclodextrin inclusion complexes. The mineral oil is a paraffin-based mineral oil; its inert long carbon chain fills the gaps in the system, synergistically maintaining the system viscosity and improving leather fullness with the fatty acid methyl esters.

[0019] The antibacterial functional monomer is a cationic quaternary ammonium salt, preferably methacryloyloxyethyltrimethylammonium chloride; the quaternary ammonium salt group can form an electrostatic interaction with the hydroxyl group on the cyclodextrin, preventing the migration of the antibacterial monomer and improving the copolymerization uniformity.

[0020] The preparation method of the antioxidant auxiliaries is as follows: A1. Add anhydrous dichloromethane and α-tocopherol to the reactor, mix well, and then lower the temperature to 0-5℃. Under an inert atmosphere, add triethylamine and methacryloyl chloride. After the addition is complete, stir at low temperature for 3-5 hours. After the reaction is complete, add deionized water to wash, collect the organic phase, dry the organic phase with anhydrous magnesium sulfate, filter, and then remove the solvent by vacuum distillation of the filtrate to obtain the α-tocopherol derivative. A2. Add 2-(diethylamino)ethyl acrylate and dodecanethiol to anhydrous ethanol, raise the temperature to 50-60°C while stirring, and add dropwise an ethanol solution of azobisisobutyronitrile and an ethanol solution of α-tocopherol derivative under an inert atmosphere. After the addition is complete, raise the temperature to 65-75°C and stir at a constant temperature for 8-12 hours. After the reaction is complete, cool to room temperature, pour into ice-cold ether, let stand for 30-50 minutes, collect the precipitate, and obtain the antioxidant auxiliary agent by washing and drying.

[0021] In step A1, the mass ratio of α-tocopherol, triethylamine, and methacryloyl chloride is 3-4.2:0.8-1.2:0.8-1.2. α-Tocopherol undergoes an esterification reaction with methacryloyl chloride, introducing carbon-carbon double bonds to obtain an α-tocopherol derivative containing copolymerization active sites, providing a basis for subsequent incorporation into the polymer chain. Triethylamine acts as an acid-binding agent, promoting the forward shift of the esterification equilibrium and preventing the hydrolysis of methacryloyl chloride at low temperatures, thereby improving the purity of the product.

[0022] In step A2, the ethanol solution of azobisisobutyronitrile is obtained by adding azobisisobutyronitrile to anhydrous ethanol and mixing evenly; the ethanol solution of α-tocopherol derivative is obtained by adding α-tocopherol derivative to anhydrous ethanol and mixing evenly; the mass ratio of 2-(diethylamino)ethyl acrylate, dodecyl mercaptan, azobisisobutyronitrile and α-tocopherol derivative is 4.5-6:0.8-1.2:0.035-0.1:2.8-3.5; the amino group of 2-(diethylamino)ethyl acrylate interacts with the hydroxyl group of cyclodextrin present in the system, improving the dispersibility of monomers in the polymerization system, the sulfur chain of dodecyl mercaptan strengthens the hydrophobic binding of leather fibers, and the α-tocopherol group imparts antioxidant properties to the leather, preventing oxidative discoloration.

[0023] In step S200, the sodium alkyl sulfate polymerization aid is sodium dodecyl sulfonate; the azo initiator is an ethylene glycol monobutyl ether solution of azobisisobutyronitrile, specifically prepared by dissolving azobisisobutyronitrile in ethylene glycol monobutyl ether, wherein the mass ratio of azobisisobutyronitrile to ethylene glycol monobutyl ether is 5-15:100.

[0024] The preparation method of the interface modifier is as follows: triethanolamine is added to the reactor and then phosphoric acid is slowly added. After stirring the reaction for 1.5-2.5 hours, the mixture is cooled to room temperature to obtain the interface modifier.

[0025] In this step, the mass ratio of triethanolamine to phosphoric acid is 1.2-1.5:1. Triethanolamine undergoes an esterification reaction with phosphoric acid to generate triethanolamine phosphate. The phosphate groups in its structure can interact with the hydroxyl groups of leather collagen fibers, significantly improving the bonding strength. In addition, the phosphate ester groups can optimize the surface polarity of leather, reduce water penetration, and improve water resistance and hand feel.

[0026] Specifically, step S300 involves: lowering the reactor temperature to 55-60℃, adding a neutralizing agent dropwise, pausing for 1-2 minutes after every 3-5 minutes of dropwise addition, controlling the reactor temperature to ≤65℃, stopping the addition of the neutralizing agent when the system pH reaches 6.5-7.5, then lowering the temperature to 45-50℃ and maintaining the temperature for 1-2 hours to obtain the fatliquoring agent.

[0027] In this step, the neutralizing agent is a mixture of sodium hydroxide and triethanolamine at a weight ratio of 1:0.25-0.45. Sodium hydroxide reacts with the carboxyl groups of acrylic acid to form sodium carboxylate, which significantly improves the water solubility of the product. Triethanolamine reacts with the free phosphoric acid in the interface modifier to form phosphate ester amine salt, and its hydroxyl groups form hydrogen bonds with the hydroxyl groups on the cyclodextrin, effectively inhibiting the stratification of the product during storage. In particular, holding the product at 45-50℃ for 1-2 hours allows the polymer chains to fully extend, reduces internal stress, and improves the stability of the product.

[0028] Preparation Example 1-1 The preparation method of antioxidant auxiliaries is as follows: A1. Add 50 parts by weight of anhydrous dichloromethane and 38 parts by weight of α-tocopherol to a reactor, mix well, and then lower the temperature to 5°C. Under a nitrogen atmosphere, add 10 parts by weight of triethylamine and 11 parts by weight of methacryloyl chloride dropwise. After the addition is complete, stir at low temperature for 4 hours. After the reaction is complete, add deionized water to wash three times, collect the organic phase, dry the organic phase with anhydrous magnesium sulfate, filter, and then remove the solvent by vacuum distillation of the filtrate to obtain the α-tocopherol derivative. A2. Add 15 parts by weight of 2-(diethylamino)ethyl acrylate and 3 parts by weight of dodecanethiol to 100 parts by weight of anhydrous ethanol. While stirring, raise the temperature to 55°C. Under a nitrogen atmosphere, add dropwise an ethanol solution of azobisisobutyronitrile (0.24 parts by weight of azobisisobutyronitrile dissolved in 12 parts by weight of anhydrous ethanol) and an ethanol solution of α-tocopherol derivative (9 parts by weight of α-tocopherol derivative dissolved in 20 parts by weight of anhydrous ethanol). After the addition is complete, raise the temperature to 70°C and stir at a constant temperature for 10 hours. After the reaction is complete, cool to room temperature and pour into ice-cold ether. After standing for 40 minutes, collect the precipitate, wash it three times with ice-cold ether, and dry it in a vacuum drying oven at 40°C for 4 hours to obtain the antioxidant auxiliary agent.

[0029] Preparation Examples 1-2 This preparation example differs from Preparation Example 1-1 in the following ways: In step A1, 50 parts by weight of anhydrous dichloromethane and 30 parts by weight of α-tocopherol are added to the reactor, and 8 parts by weight of triethylamine and 8 parts by weight of methacryloyl chloride are added dropwise under a nitrogen atmosphere; in step A2, 13.5 parts by weight of 2-(diethylamino)ethyl acrylate and 2.4 parts by weight of dodecanethiol are added to 100 parts by weight of anhydrous ethanol; the ethanol solution of azobisisobutyronitrile is obtained by adding 0.1 parts by weight of azobisisobutyronitrile to 10 parts by weight of anhydrous ethanol and mixing them evenly; the ethanol solution of the α-tocopherol derivative is obtained by adding 5.4 parts by weight of the α-tocopherol derivative to 15 parts by weight of anhydrous ethanol and mixing them evenly.

[0030] Preparation Examples 1-3 This preparation example differs from Preparation Example 1-1 in the following ways: In step A1, 65 parts by weight of anhydrous dichloromethane and 42 parts by weight of α-tocopherol are added to the reactor, and 12 parts by weight of triethylamine and 12 parts by weight of methacryloyl chloride are added dropwise under a nitrogen atmosphere; in step A2, 18 parts by weight of 2-(diethylamino)ethyl acrylate and 3.6 parts by weight of dodecanethiol are added to 120 parts by weight of anhydrous ethanol; the ethanol solution of azobisisobutyronitrile is obtained by adding 0.3 parts by weight of azobisisobutyronitrile to 15 parts by weight of anhydrous ethanol and mixing them evenly; the ethanol solution of the α-tocopherol derivative is obtained by adding 10.5 parts by weight of the α-tocopherol derivative to 25 parts by weight of anhydrous ethanol and mixing them evenly.

[0031] Example 1 A method for preparing a polymer waterproofing and fatliquoring agent includes the following steps: S100. Dissolve 20 parts by weight of 2-hydroxypropyl-β-cyclodextrin in 100 parts by weight of deionized water, heat to 55°C, add 40 parts by weight of octadecyl acrylate and 20 parts by weight of octadecyl methacrylate while stirring, and keep the temperature at 55°C and stir for 2.5 hours to obtain a cyclodextrin-long-chain acrylate inclusion complex dispersion. S200: Add 30 parts by weight of ethylene glycol monobutyl ether and 16 parts by weight of viscosity modifier to the reactor. After mixing evenly, purge with nitrogen to replace the air. Then add 25 parts by weight of cyclodextrin-acrylic acid long-chain ester inclusion complex dispersion, 20 parts by weight of hexadecene, 25 parts by weight of acrylic acid, 6 parts by weight of methacryloyloxyethyltrimethylammonium chloride, and 5 parts by weight of the antioxidant auxiliary prepared in Preparation Example 1-1. Heat to 70°C, and add 0.3 parts by weight of sodium dodecyl sulfonate while stirring. After stirring evenly, add 18.7 parts by weight of azo initiator dropwise. After the addition is complete, raise the temperature to 85°C and keep it at that temperature for 2 hours. Then add another 0.7 parts by weight of sodium dodecyl sulfonate and 3.3 parts by weight of azo initiator dropwise. Continue to keep it at that temperature for 2 hours. Finally, add 10 parts by weight of... An interface modifier was prepared by cooling the mixture to 70°C and holding it at that temperature for 2 hours to obtain a blend. The viscosity modifier consisted of a 1:1 mass ratio of fatty acid methyl ester and mineral oil. Specifically, the fatty acid methyl ester was a 1:2.5:4.5 mass ratio of methyl hexanoate, methyl octanoate, and methyl decanoate, and the mineral oil was paraffin-based mineral oil. The azo initiator was a solution of azobisisobutyronitrile in ethylene glycol monobutyl ether, prepared by dissolving azobisisobutyronitrile in ethylene glycol monobutyl ether at a mass ratio of 12:100. The interface modifier was prepared by slowly adding phosphoric acid after adding triethanolamine to a reactor, stirring the reaction for 2 hours, and then cooling to room temperature to obtain the interface modifier, wherein the mass ratio of triethanolamine to phosphoric acid was 1.4:1. S300. After lowering the reactor temperature to 55℃, add a neutralizing agent dropwise, pausing for 1 minute after every 4 minutes of dropwise addition, and control the reactor temperature to ≤65℃. When the pH value of the system reaches 7.0, stop adding the neutralizing agent, then lower the temperature to 45℃ and keep it at that temperature for 1.5 hours to obtain the fatliquoring agent. The neutralizing agent is a mixture of sodium hydroxide and triethanolamine in a weight ratio of 1:0.3.

[0032] Example 2 This embodiment differs from Embodiment 1 in the following ways: In step S100, 16 parts by weight of 2-hydroxypropyl-β-cyclodextrin are dissolved in 80 parts by weight of deionized water, heated to 50°C, and 21 parts by weight of octadecyl acrylate and 16 parts by weight of octadecyl methacrylate are added while stirring. The mixture is kept at 50°C and stirred for 2 hours. In step S200, 25 parts by weight of ethylene glycol monobutyl ether and 12 parts by weight of viscosity modifier are added to the reactor. After mixing evenly, nitrogen is introduced to replace the air. Then, 15 parts by weight of cyclodextrin-acrylic acid long-chain ester inclusion complex dispersion, 12 parts by weight of hexadecene, 18 parts by weight of acrylic acid, 4 parts by weight of methacryloyloxyethyltrimethylammonium chloride, and 3 parts by weight of antioxidant prepared in Preparation Examples 1-2 are added. The temperature is heated to 65°C, and 0.2 parts by weight of sodium dodecyl sulfonate are added while stirring. After stirring evenly, 16 parts by weight of azo initiator are added dropwise. After the addition is completed, the temperature is raised to 80°C and kept at that temperature for 1 hour. Then, 0.6 parts by weight of sodium dodecyl sulfonate and 3 parts by weight of azo initiator are added dropwise. The temperature is kept at that temperature for another 1.5 hours. 10 parts by weight of interface modifier are added, and the temperature is lowered to 70°C and kept at that temperature for 2 hours to obtain the blend. In step S300, after the reactor temperature is lowered to 55°C, a neutralizing agent is added dropwise, with a 1-minute pause after every 3 minutes of addition, and the temperature inside the reactor is controlled to be ≤65°C. When the pH value of the system reaches 7.0, the addition of the neutralizing agent is stopped, and then the temperature is lowered to 45°C and kept at that temperature for 1 hour to obtain the fatliquoring agent.

[0033] Example 3 This embodiment differs from Embodiment 1 in the following ways: In step S100, 25 parts by weight of 2-hydroxypropyl-β-cyclodextrin are dissolved in 120 parts by weight of deionized water, the temperature is raised to 50°C, and 55 parts by weight of octadecyl acrylate and 30 parts by weight of octadecyl methacrylate are added while stirring. The mixture is kept at 55°C and stirred for 3 hours. In step S200, 45 parts by weight of ethylene glycol monobutyl ether and 20 parts by weight of viscosity modifier are added to the reactor. After mixing evenly, nitrogen is introduced to replace the air. Then, 32 parts by weight of cyclodextrin-acrylic acid long-chain ester inclusion complex dispersion, 25 parts by weight of hexadecene, 32 parts by weight of acrylic acid, 7 parts by weight of methacryloyloxyethyltrimethylammonium chloride, and 6 parts by weight of antioxidant prepared in Examples 1-3 are added. The temperature is heated to 75°C, and 0.5 parts by weight of sodium dodecyl sulfonate are added while stirring. After stirring evenly, 22 parts by weight of azo initiator are added dropwise. After the addition is completed, the temperature is raised to 85°C and kept at that temperature for 3 hours. Then, 0.9 parts by weight of sodium dodecyl sulfonate and 4.5 parts by weight of azo initiator are added dropwise. The temperature is kept at that temperature for another 2.5 hours. 10 parts by weight of interface modifier are added, and the temperature is lowered to 75°C and kept at that temperature for 3 hours to obtain the blend. In step S300, after the reactor temperature is lowered to 60°C, a neutralizing agent is added dropwise, with a 2-minute pause after every 5 minutes of addition, and the temperature inside the reactor is controlled to be ≤65°C. When the pH value of the system reaches 7.0, the addition of the neutralizing agent is stopped, and then the temperature is lowered to 50°C and kept at that temperature for 2 hours to obtain the fatliquoring agent.

[0034] Example 4 Compared with Example 1, the method of adding the polymerization aid and azo initiator in step S200 is different in this embodiment. The rest is the same as in Example 1, as follows: In step S200, 30 parts by weight of ethylene glycol monobutyl ether and 16 parts by weight of viscosity modifier are added to the reactor. After mixing evenly, nitrogen is introduced to replace the air. Then, 25 parts by weight of cyclodextrin-acrylic acid long-chain ester inclusion complex dispersion, 20 parts by weight of hexadecene, 25 parts by weight of acrylic acid, 6 parts by weight of methacryloyloxyethyltrimethylammonium chloride, and 5 parts by weight of antioxidant prepared in Preparation Example 1-1 are added. The temperature is heated to 70°C, and 1 part by weight of sodium dodecyl sulfonate is added while stirring. After stirring evenly, 22 parts by weight of azo initiator are added. After the addition is completed, the temperature is raised to 85°C and kept at that temperature for 4 hours. Then, 10 parts by weight of interface modifier are added, and the temperature is lowered to 70°C and kept at that temperature for 2 hours to obtain a blend. The viscosity modifier is a mixture of fatty acid methyl ester and mineral oil in a mass ratio of 1:1. Specifically, the fatty acid methyl ester is a mixture of methyl hexanoate, methyl octanoate, and methyl decanoate in a mass ratio of 1:2.5:4.5, and the mineral oil is paraffinic mineral oil. The azo initiator is an ethylene glycol monobutyl ether solution of azobisisobutyronitrile (AIB), specifically prepared by dissolving AIB in ethylene glycol monobutyl ether, wherein the mass ratio of AIB to ethylene glycol monobutyl ether is 12:100. The interface modifier is prepared by slowly adding phosphoric acid after adding triethanolamine to a reactor, stirring the reaction for 2 hours, and then cooling to room temperature to obtain the interface modifier, wherein the mass ratio of triethanolamine to phosphoric acid is 1.4:1.

[0035] Comparative Example 1 Compared with Example 1, this comparative example does not add an interface modifier during the preparation process in step S200, but the rest is the same as in Example 1, specifically: In step S200, 30 parts by weight of ethylene glycol monobutyl ether and 16 parts by weight of viscosity modifier are added to the reactor. After mixing evenly, nitrogen gas is introduced to replace the air. Then, 25 parts by weight of cyclodextrin-acrylic acid long-chain ester inclusion complex dispersion, 20 parts by weight of hexadecene, 25 parts by weight of acrylic acid, 6 parts by weight of methacryloyloxyethyltrimethylammonium chloride, and 5 parts by weight of the antioxidant auxiliary prepared in Preparation Example 1-1 are added. The temperature is heated to 70°C, and 0.3 parts by weight of sodium dodecyl sulfonate is added while stirring. After stirring evenly, 18.7 parts by weight of azo initiator are added. After the addition is completed, the temperature is raised to 85°C and maintained. After heating for 2 hours, 0.7 parts by weight of sodium alkyl dodecyl sulfonate and 3.3 parts by weight of azo initiator were added, and the mixture was kept at this temperature for another 4 hours to obtain a blend. The viscosity modifier was a mixture of fatty acid methyl ester and mineral oil in a mass ratio of 1:1. Specifically, the fatty acid methyl ester was a mixture of methyl hexanoate, methyl octanoate, and methyl decanoate in a mass ratio of 1:2.5:4.5, and the mineral oil was paraffinic mineral oil. The azo initiator was a solution of azobisisobutyronitrile in ethylene glycol monobutyl ether, specifically prepared by dissolving azobisisobutyronitrile in ethylene glycol monobutyl ether, wherein the mass ratio of azobisisobutyronitrile to ethylene glycol monobutyl ether was 12:100.

[0036] Comparative Example 2 Compared with Example 1, this comparative example uses α-tocopherol as an antioxidant adjuvant, while the rest is the same as in Example 1. Specifically: In step S200, 30 parts by weight of ethylene glycol monobutyl ether and 16 parts by weight of viscosity modifier are added to the reactor. After mixing evenly, nitrogen is introduced to replace the air. Then, 25 parts by weight of cyclodextrin-acrylic acid long-chain ester inclusion complex dispersion, 20 parts by weight of hexadecene, 25 parts by weight of acrylic acid, 6 parts by weight of methacryloyloxyethyltrimethylammonium chloride, and 5 parts by weight of α-tocopherol are added. The temperature is heated to 70°C, and 0.3 parts by weight of sodium dodecyl sulfonate is added while stirring. After stirring evenly, 18.7 parts by weight of azo initiator are added dropwise. After the addition is complete, the temperature is raised to 85°C and kept at that temperature for 2 hours. Then, 0.7 parts by weight of sodium dodecyl sulfonate and 3.3 parts by weight of azo initiator are added dropwise. The temperature is kept at that temperature for another 2 hours. Finally, 10 parts by weight of interface... The modifier was cooled to 70℃ and held for 2 hours to obtain a blend. The viscosity adjuster was a mixture of fatty acid methyl ester and mineral oil in a 1:1 mass ratio. Specifically, the fatty acid methyl ester was a mixture of methyl hexanoate, methyl octanoate, and methyl decanoate in a mass ratio of 1:2.5:4.5, and the mineral oil was paraffinic mineral oil. The azo initiator was a solution of azobisisobutyronitrile in ethylene glycol monobutyl ether, specifically prepared by dissolving azobisisobutyronitrile in ethylene glycol monobutyl ether, with a mass ratio of azobisisobutyronitrile to ethylene glycol monobutyl ether of 12:100. The interface modifier was prepared by slowly adding phosphoric acid after adding triethanolamine to a reactor, stirring for 2 hours, and then cooling to room temperature to obtain the interface modifier, with a mass ratio of triethanolamine to phosphoric acid of 1.4:1.

[0037] Comparative Example 3 Compared with Example 1, this comparative example does not add antioxidants during the preparation process in step S200, but the rest is the same as in Example 1: In step S200, 30 parts by weight of ethylene glycol monobutyl ether and 16 parts by weight of viscosity adjuster are added to the reactor. After mixing evenly, nitrogen is introduced to replace the air. Then, 25 parts by weight of cyclodextrin-acrylic acid long-chain ester inclusion complex dispersion, 20 parts by weight of hexadecene, 25 parts by weight of acrylic acid, and 6 parts by weight of methacryloyloxyethyltrimethylammonium chloride are added. The temperature is heated to 70°C, and 0.3 parts by weight of sodium dodecyl sulfonate is added while stirring. After stirring evenly, 18.7 parts by weight of azo initiator are added dropwise. After the addition is complete, the temperature is raised to 85°C and kept at that temperature for 2 hours. Then, 0.7 parts by weight of sodium dodecyl sulfonate and 3.3 parts by weight of azo initiator are added dropwise. The temperature is kept at that temperature for another 2 hours. Finally, 10 parts by weight of interface modifier are added to reduce the temperature. The mixture was heated to 70℃ and kept at that temperature for 2 hours to obtain a blend. The viscosity modifier was a mixture of fatty acid methyl ester and mineral oil in a 1:1 mass ratio. Specifically, the fatty acid methyl ester was a mixture of methyl hexanoate, methyl octanoate, and methyl decanoate in a mass ratio of 1:2.5:4.5, and the mineral oil was paraffin-based mineral oil. The azo initiator was a solution of azobisisobutyronitrile in ethylene glycol monobutyl ether, prepared by dissolving azobisisobutyronitrile in ethylene glycol monobutyl ether, with a mass ratio of azobisisobutyronitrile to ethylene glycol monobutyl ether of 12:100. The interface modifier was prepared by slowly adding phosphoric acid after adding triethanolamine to a reactor, stirring the reaction for 2 hours, and then cooling to room temperature to obtain the interface modifier, with a mass ratio of triethanolamine to phosphoric acid of 1.4:1.

[0038] Comparative Example 4 Compared with Example 1, this comparative example does not include the cyclodextrin-long-chain acrylic acid ester inclusion complex during preparation; all other aspects are the same as in Example 1. Specifically: S1. Add 30 parts by weight of ethylene glycol monobutyl ether and 16 parts by weight of viscosity modifier to the reactor. After mixing evenly, purge with nitrogen to replace the air. Then add 20 parts by weight of hexadecene, 25 parts by weight of acrylic acid, 6 parts by weight of methacryloyloxyethyltrimethylammonium chloride, and 5 parts by weight of the antioxidant prepared in Preparation Example 1-1. Heat to 70°C. While stirring, add 0.3 parts by weight of sodium dodecyl sulfonate. After stirring evenly, add 18.7 parts by weight of azo initiator dropwise. After the addition is complete, raise the temperature to 85°C and keep it at that temperature for 2 hours. Then add another 0.7 parts by weight of sodium dodecyl sulfonate and another 3.3 parts by weight of azo initiator dropwise. Continue to keep it at that temperature for 2 hours. Add 10 parts by weight of interface modifier and lower the temperature to 70°C. The mixture was kept at a constant temperature for 2 hours to obtain a blend. The viscosity modifier was a mixture of fatty acid methyl ester and mineral oil in a 1:1 mass ratio. Specifically, the fatty acid methyl ester was a mixture of methyl hexanoate, methyl octanoate, and methyl decanoate in a mass ratio of 1:2.5:4.5, and the mineral oil was paraffin-based mineral oil. The azo initiator was a solution of azobisisobutyronitrile in ethylene glycol monobutyl ether, specifically prepared by dissolving azobisisobutyronitrile in ethylene glycol monobutyl ether, with a mass ratio of azobisisobutyronitrile to ethylene glycol monobutyl ether of 12:100. The interface modifier was prepared by slowly adding phosphoric acid after adding triethanolamine to a reactor, stirring the reaction for 2 hours, and then cooling to room temperature to obtain the interface modifier, with a mass ratio of triethanolamine to phosphoric acid of 1.4:1. S2. After lowering the reactor temperature to 55℃, add a neutralizing agent dropwise, pausing for 1 minute after every 4 minutes of dropwise addition, and control the reactor temperature to ≤65℃. When the pH value of the system reaches 7.0, stop adding the neutralizing agent, then lower the temperature to 45℃ and keep it at that temperature for 1.5 hours to obtain the fatliquoring agent. The neutralizing agent is a mixture of sodium hydroxide and triethanolamine in a weight ratio of 1:0.3.

[0039] Comparative Example 5 A method for preparing a polymer waterproofing and fatliquoring agent includes the following steps: S1. Add 30 parts by weight of ethylene glycol monobutyl ether and 16 parts by weight of viscosity modifier to the reactor. After mixing evenly, purge with nitrogen to replace the air. Then add 20 parts by weight of hexadecene, 25 parts by weight of acrylic acid, and 6 parts by weight of methacryloyloxyethyltrimethylammonium chloride. Heat to 70°C. While stirring, add 0.3 parts by weight of sodium dodecyl sulfonate. After stirring evenly, add 18.7 parts by weight of azo initiator dropwise. After the addition is complete, raise the temperature to 85°C and keep it at that temperature for 2 hours. Then add another 0.7 parts by weight of sodium dodecyl sulfonate and dropwise 3 parts by weight of ethylene glycol monobutyl ether. 3 parts by weight of azo initiator were added and kept at the temperature for 4 hours to obtain a blend. The viscosity modifier was a mixture of fatty acid methyl ester and mineral oil in a mass ratio of 1:1. Specifically, the fatty acid methyl ester was a mixture of methyl hexanoate, methyl octanoate, and methyl decanoate in a mass ratio of 1:2.5:4.5, and the mineral oil was paraffinic mineral oil. The azo initiator was a solution of azobisisobutyronitrile in ethylene glycol monobutyl ether, specifically prepared by dissolving azobisisobutyronitrile in ethylene glycol monobutyl ether, wherein the mass ratio of azobisisobutyronitrile to ethylene glycol monobutyl ether was 12:100. S2. After lowering the reactor temperature to 55℃, add a neutralizing agent dropwise, pausing for 1 minute after every 4 minutes of dropwise addition, and control the reactor temperature to ≤65℃. When the pH value of the system reaches 7.0, stop adding the neutralizing agent, then lower the temperature to 45℃ and keep it at that temperature for 1.5 hours to obtain the fatliquoring agent. The neutralizing agent is a mixture of sodium hydroxide and triethanolamine in a weight ratio of 1:0.3.

[0040] Related tests: The application performance of the fatliquoring agents prepared in Examples 1 to 4 and Comparative Examples 1 to 5 was verified using wet white sheep leather tanned with the commercially available organic chromium-free tanning agent TWS (purchased from Zhejiang Tongtianxing Group Co., Ltd.). First, the backline of the TWS organic tanned sheep leather was folded in half and cut into leather samples with basically the same weight and area. Then, the application test was carried out according to the processing technology in Table 1.

[0041] Table 1 Application Test Process of Fat Additives Thickness increase test: Lay the hide out and select five different parts, including the four corners and the middle, to measure the thickness with a thickness gauge and record the readings to obtain the average thickness of the leather before neutralization and at the end of application; Average thickness increase (%) = (d2-d1) / d1×100%; where d1 is the average thickness of the leather before neutralization, mm; d2 is the average thickness of the leather at the end of application, mm.

[0042] Softness test: The softness of the leather is determined using the GT-303 leather softness tester.

[0043] Contact angle test: The contact angle of the grain surface of the leather sample was tested using an optical contact angle meter.

[0044] The test results are shown in Table 2.

[0045] Table 2. Test results of thickness increase rate, softness, and contact angle. As can be seen from the data in Table 2, each embodiment exhibits a greater thickening rate and softness compared to the comparative examples. This indicates that the fatliquoring agents prepared in each embodiment have a good filling and thickening effect between leather fibers and can be evenly distributed between the leather fibers, making the leather samples feel softer. Furthermore, the contact angle of the treated leather is above 90°, especially that of Example 1, which reaches above 125°, demonstrating good hydrophobicity.

[0046] Tensile strength test: The tensile strength was tested in accordance with the relevant provisions of QB / T 2710-2018; Yellowing resistance test: The yellowing resistance of the samples prepared in each example and comparative example was tested using a TST-E704 yellowing aging tester. The test results are shown in Table 3.

[0047] Table 3. Test results of tensile strength and yellowing resistance As can be seen from the data in Table 3, the tensile strength of the examples is superior to that of the comparative examples, indicating that the fatliquoring agent of the present invention has an excellent fatliquoring effect on leather fibers. The test examples with added antioxidants showed relatively high yellowing resistance, indicating that the addition of antioxidants can effectively improve the yellowing problem.

[0048] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0049] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a polymer waterproofing and fatliquoring agent, characterized in that, Includes the following steps: S100. A cyclodextrin-long-chain acrylate inclusion complex dispersion was prepared using raw materials including 2-hydroxypropyl-β-cyclodextrin, octadecyl acrylate, and octadecyl methacrylate; wherein the mass ratio of 2-hydroxypropyl-β-cyclodextrin, octadecyl acrylate, and octadecyl methacrylate was 0.15-0.25:0.2-0.6:0.15-0.

3. S200: Add ethylene glycol monobutyl ether and viscosity adjuster to the reactor, mix well, and then purge with inert gas to replace the air. Then add cyclodextrin-acrylic acid long-chain ester inclusion complex dispersion, hexadecene, acrylic acid, antibacterial functional monomer, and antioxidant. Heat to 65-75℃, and add 20%-50% of the required amount of sodium alkyl sulfate polymerization aid while stirring. After stirring evenly, add 80%-90% of the required amount of azo initiator. After the addition is complete, raise the temperature to 80-85℃ and keep it at that temperature for 1-3 hours. Then add the remaining sodium alkyl sulfate polymerization aid and azo initiator, and continue to keep it at that temperature for 1.5-2.5 hours. Add an interface modifier, lower the temperature to 70-75℃ and keep it at that temperature for 1-3 hours to obtain the blend. The viscosity modifier is a mixture of fatty acid methyl ester and mineral oil; the fatty acid methyl ester is a mixture of methyl hexanoate, methyl octanoate, and methyl decanoate in a mass ratio of 1-2:2-3:4-5; the interface modifier is prepared by adding triethanolamine to a reactor, then slowly adding phosphoric acid, stirring and reacting for 1.5-2.5 hours, and then cooling to room temperature to obtain the interface modifier; the mass ratio of triethanolamine to phosphoric acid is 1.2-1.5:

1. S300. After lowering the reactor temperature to 55-60℃, add a neutralizing agent dropwise, pausing for 1-2 minutes after every 3-5 minutes of dropwise addition, and control the reactor temperature to ≤65℃. When the pH value of the system reaches 6.5-7.5, stop adding the neutralizing agent, then lower the temperature to 45-50℃ and keep it at that temperature for 1-2 hours to obtain the fatliquoring agent. The preparation method of the antioxidant auxiliaries is as follows: A1. Add anhydrous dichloromethane and α-tocopherol to the reactor, mix well, and then lower the temperature to 0-5℃. Under an inert atmosphere, add triethylamine and methacrylamide chloride. After the addition is complete, stir at low temperature for 3-5 hours. After the reaction is complete, add deionized water to wash, collect the organic phase, and obtain the α-tocopherol derivative after drying and vacuum distillation. A2. Add 2-(diethylamino)ethyl acrylate and dodecanethiol to anhydrous ethanol, raise the temperature to 50-60°C while stirring, and add dropwise an ethanol solution of azobisisobutyronitrile and an ethanol solution of α-tocopherol derivative under an inert atmosphere. After the addition is complete, raise the temperature to 65-75°C and stir at a constant temperature for 8-12 hours. After the reaction is complete, cool to room temperature, pour into ice-cold ether, let stand for 30-50 minutes, collect the precipitate, and obtain the antioxidant auxiliary agent by washing and drying.

2. The method for preparing a polymer waterproofing and fatliquoring agent according to claim 1, characterized in that, Step S100 specifically involves dissolving 2-hydroxypropyl-β-cyclodextrin in deionized water, heating it to 50-55°C, adding octadecyl acrylate and octadecyl methacrylate while stirring, and stirring at a constant temperature for 2-3 hours to obtain a cyclodextrin-long-chain acrylic acid ester inclusion complex dispersion.

3. The method for preparing a polymer waterproofing and fatliquoring agent according to claim 1, characterized in that, The neutralizing agent is a mixture of sodium hydroxide and triethanolamine in a weight ratio of 1:0.25-0.

45.

4. A polymer waterproofing and fatliquoring agent, characterized in that, It is prepared by the method of any one of claims 1-3 for preparing a polymer waterproofing and fatliquoring agent.

Images