Polymer retanning fatliquor as well as preparation method and application thereof

Abstract

The invention discloses a polymer retanning fatliquor as well as a preparation method and application thereof. The polymer retanning fatliquor is prepared from castor oil polyoxyethylene ether, acrylic acid and methacrylic acid as main raw materials through free radical graft polymerization reaction in a water phase under the action of an initiator. As a nonionic amphiphilic castor oil polyoxyethylene ether monomer structural unit is introduced into a copolymer molecular chain of the retanning and fatting agent, the retanning and fatting agent is applied to a leather retanning and fatting process, not only has relatively good acid-resistant stability, but also can enable a leather blank to have good softness, oily feeling and fullness.

Description

Technical Field

[0001] The invention relates to the technical field of leather, in particular to a polymer retanning fatliquor and a preparation method and application thereof. Background Art

[0002] Retanning and fatliquoring are two important processes in the leather production process. Retanning can increase the effect of the main tanning and give leather special properties, and is known as the "alchemy" in the leather production process. Fatliquoring can lubricate leather fibers and give leather softness and plumpness, and is one of the indispensable processes in leather making. Polymer retanning fatliquoring agents have both retanning and fatliquoring functions. They can lubricate leather fibers, prevent leather from stiffening and cracking, and make leather have corresponding toughness and softness, and maintain its strength. At the same time, a part of the fatliquoring agent combined with chrome leather fibers can also play a role in slight supplementary tanning, filling, dyeing and fixing, and slowing down the migration of chrome tanning agents. The polymer fatliquoring agent leather chemical has good compatibility with other retanning agents and fatliquoring agents, has strong affinity with chrome tanning, and is firmly combined. After the retanning and fatliquoring treatment, it does not affect the water-based finishing of the crust leather, and has little effect on the air permeability and water permeability of the leather. Therefore, the polymer retanning fatliquoring agent can be used in the production of various types of leather.

[0003] Polymer retanning fatliquor is an amphiphilic macromolecular compound, which is mainly obtained by free radical copolymerization of a lipophilic monomer containing a long chain alkyl group with a double bond and a hydrophilic monomer containing a carboxyl group. According to the way of introducing the hydrophobic group into the polymer molecular structure, the preparation methods are mainly: (1) copolymerization of acrylic acid with alkyl acrylate; (2) copolymerization of acrylic acid with maleic anhydride derivatives.

[0004] There are document records using octadecyl acrylate and acrylic acid as reaction monomers, ethylene glycol monobutyl ether as reaction medium, dodecyl mercaptan as molecular weight regulator, benzoyl peroxide as initiator to prepare series polymer retanning fatting agent. This retanning fatting agent shows better fatting performance, and has good combination with crust leather (Du J, Shi L, Peng B. Amphiphilic acrylate copolymer fat liquor forecological leather: Influence of molecular weight on performances [J]. Journal of Applied Polymer Science, 2016, 133 (20): 43440). There is also a method of synthesizing acrylic acid-methacrylic acid hexadecyl ester polymer retanning fatting agent with amphiphilic structure using acrylic acid and methacrylic acid hexadecyl ester as raw materials, azobisisobutyronitrile as initiator, and ethylene glycol monobutyl ether as solvent. By changing the monomer ratio, products with obvious retanning, fatliquor and waterproof properties can be obtained (Wang Jiatu, Xi Xianfeng, Wang Biqing, et al. Study on the properties of acrylic ester polymer fatliquor emulsion [J]. Fine Chemicals, 2004, 21 (04): 285-287). This method mainly uses monomers such as octadecyl acrylate and hexadecanol methacrylate. These monomers are insoluble in water and need to be copolymerized in a solvent, which is not conducive to environmental protection. Most of the synthesized polymer retanning fatliquors can be used for functional waterproof leather processing.

[0005] There are also literature reports on the preparation of retanning fat-liquor with acrylic acid and maleic anhydride derivatives as monomer raw materials. Common maleic anhydride derivatives include maleic acid fatty alcohol monoester / diester, modified natural animal / plant maleic anhydride derivatives. Related studies have shown that RF series polymer retanning fat-liquor is prepared by free radical copolymerization with maleic acid hexadecanol monoester and acrylic acid as reaction raw materials. The product will lead to different softness of finished products applied to leather as the amount of acrylic acid used in the polymerization process changes (Zhou Jianfei, Zou Xianglong, Lan Yunjun. Study on the application performance of hexadecanol maleic acid monoester-acrylic acid polymer fat-liquor [J]. Western Leather, 2007, 29 (06): 22-24). Maleic anhydride and animal and plant oils are copolymerized to prepare an oil-based polymer intermediate. Then, organosilicon and high-grade fatty alcohol are used for esterification grafting modification to prepare a retanning fat-liquor. The obtained product has good fat-liquoring performance and retanning and filling performance (Luo Chaoyang, Lu Yan, Fan Haojun, et al. Preparation and Performance Study of Washable Polymer Fat-liquoring Agent [J]. China Leather, 2007, 36 (17): 39-44). This type of method mainly uses maleic anhydride mono- and diester derivatives for modification polymerization. The intermediate preparation is simple and easy, but cis- and trans-isomers will occur during the esterification of maleic anhydride, and the generation of cis- and trans-isomers and the influence of the generated ratio on polymerization and the influence on retanning and fat-liquoring are not involved. Maleic anhydride derivatives are mostly raw materials for the synthesis of lipophilic monomers, and the fat-liquoring performance is poor (a preparation method of a polymer retanning fat-liquoring agent and a retanning fat-liquoring agent, CN109880944B).

[0006] Although considerable research results have been achieved on the synthesis and application of the above-mentioned polymer retanning and fatliquor, there are still some shortcomings, such as the environmental pollution (the addition of organic solvents is required), insufficient fatliquor oiliness, poor softness, etc., which make it difficult to meet the requirements of retanning and fatliquor in leather making.

[0007] On the basis of comprehensively utilizing the advantages of the above-mentioned retanning and fat-liquor research, and avoiding the existing deficiencies, there is a study using natural vegetable oil castor oil as raw material, because of its special chemical structure and good lubrication, while ensuring that it has an oily feeling, it improves its hydrophilicity, and it is mainly used to prepare leather fat-liquor by sulfation modification. There is a document that on the basis of the successfully developed sulfated castor oil / methacrylic acid / acrylonitrile terpolymer leather retanning and fat-liquor, a suitable monomer is selected to make the product have the functions of tanning and fat-liquor (Shen Yiding, Li Xiaorui, Zhao Fuzhong. Preparation and structural characterization of amphoteric acrylic resin emulsion [J]. Polymer Materials Science and Engineering, 1992, (1): 30-34). Castor oil is sulfated and then grafted with (meth) acrylic acid and other monomers for polymerization. This method can be polymerized in the water phase, avoiding the use of solvents, and to a certain extent increasing the oiliness and softness of the retanned and fat-liquored leather. However, due to the presence of sulfated castor oil structure, the product has poor acid and electrolyte resistance, which greatly limits the application and promotion of the retanning fatliquor prepared by this method in leather processing technology.

[0008] Therefore, there is an urgent need for a leather chemical with both retanning and fatliquoring effects prepared under aqueous conditions. Such products should not only meet certain softness, oiliness and filling effects, but also have good acid-resistant structural stability. This will be more conducive to the application performance of such retanning and fatliquoring products in the leather field.

[0009] In view of this, the present invention is proposed. Summary of the invention

[0010] The purpose of the present invention is to overcome the defects of the prior art and provide a polymer retanning fatliquor and a preparation method and application thereof.

[0011] The present invention solves the technical problem by adopting the following technical solutions.

[0012] The invention provides a polymer retanning and fatting agent. The raw materials for preparing the polymer retanning and fatting agent include castor oil polyoxyethylene ether. The addition number of ethylene oxide in the castor oil polyoxyethylene ether is 20 or 40.

[0013] The present invention also provides a method for preparing the polymer retanning and fatliquor, which comprises: subjecting a monomer containing castor oil polyoxyethylene ether and a monomer solution containing acrylic acid to free radical graft polymerization in an aqueous phase to obtain the polymer retanning and fatliquor.

[0014] The present invention also provides application of the polymer retanning and fatliquor agent or the polymer retanning and fatliquor agent prepared by the preparation method in leather processing.

[0015] The present invention has the following beneficial effects:

[0016] The present invention provides a polymer retanning and fatting agent, and a preparation method and application thereof. The raw materials for preparing the polymer retanning and fatting agent provided by the present invention include castor oil polyoxyethylene ether, and the ethylene oxide addition number in the castor oil polyoxyethylene ether is 20 or 40. A nonionic amphiphilic castor oil polyoxyethylene ether monomer structural unit is introduced into the copolymer molecular chain of the polymer retanning and fatting agent, and the polymer retanning and fatting agent is applied in the leather retanning and fatting process, which not only has good acid resistance and stability, but also makes the leather blank have good softness, oiliness and fullness. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 Schematic diagram of the segmentation diagram of the first layer of yellow cattle wet blue hide. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0020] The polymer retanning fatliquor provided in the embodiments of the present invention and its preparation method and application are described in detail below.

[0021] In a first aspect, an embodiment of the present invention provides a polymer retanning and fatliquor. The raw materials for preparing the polymer retanning and fatliquor include castor oil polyoxyethylene ether. The addition number of ethylene oxide in the castor oil polyoxyethylene ether is 20 or 40.

[0022] The polymer retanning fatliquor provided by the embodiment of the present invention introduces a nonionic amphiphilic castor oil polyoxyethylene ether monomer structural unit into the copolymer molecular chain of the polymer retanning fatliquor. Since the castor oil polyoxyethylene ether series monomer is a nonionic amphiphilic substance with good water solubility, the polymerization reaction can be carried out in an aqueous phase system, which meets the requirements of environmental protection. In addition, the nonionic castor oil polyoxyethylene ether series monomer has acid resistance and stability, and can make the polymer retanning fatliquor have good softness, oiliness and filling degree. It is worth noting that the raw material castor oil polyoxyethylene ether used to prepare the polymer retanning fatting agent has an ethylene oxide addition number of 20 or 40. When the ethylene oxide addition number is greater than 40, the molecular weight increases, the epoxide addition number is large, and the appearance changes from liquid to paste or solid, which makes it difficult to react, and the emulsification is too strong, lacking the oily feel that the polymer fatting agent should have; when the ethylene oxide addition number is less than 20, the molecular weight is small, the epoxide addition number is small, it is difficult to emulsify, or it is insoluble in water. Therefore, it is more appropriate for the ethylene oxide addition number in castor oil polyoxyethylene ether to be 20 or 40.

[0023] In some optional embodiments, the raw materials for preparing the polymer retanning fatliquor include castor oil polyoxyethylene ether, acrylic acid and methacrylic acid, and the ethylene oxide addition number in the castor oil polyoxyethylene ether is 20 or 40, and the molar ratio of castor oil polyoxyethylene ether, acrylic acid and methacrylic acid is 1:(3-6):(2.2-4).

[0024] Controlling the molar ratio of castor oil polyoxyethylene ether, acrylic acid and methacrylic acid to 1: (3-6): (2.2-4) has the following advantages:

[0025] (1) Physical properties that can be given to polymer retanning agents: The finished product synthesized within this range has a viscosity of 1400 to 4000 Pa·s at 40°C;

[0026] (2) It can give the finished product good application performance: The polymer retanning fatliquor can give the leather embryo better softness, oiliness and plumpness. The finished product synthesized within this range has a viscosity (indirectly reflecting the molecular weight) suitable for penetration and bonding in the leather embryo; too high a viscosity is not conducive to penetration, and too low a viscosity is not conducive to bonding between fibers;

[0027] (3) It can give the finished product a good structure: Acrylic acid and methacrylic acid are active monomers and are easy to form homopolymers. If the amount used is too large, the finished product is easy to form linear homopolymers, and the filling performance when used in skin embryos is weak; castor oil polyoxyethylene ether is a copolymer and is not easy to form a homopolymer.

[0028] In some optional embodiments, the main component of the polymer retanning fatliquor is castor oil polyoxyethylene ether-based acrylic resin.

[0029] In some optional embodiments, the structure of the castor oil polyoxyethylene ether-based acrylic resin is shown below:

[0030]

[0031] Wherein, a represents the degree of polymerization, and the structural formula of R1 is:

[0032]

[0033] Wherein, n=x+y+z, n is the average amount of ethylene oxide combined with 1 mol of castor oil, and n is 20 or 40.

[0034] In a second aspect, an embodiment of the present invention further provides a method for preparing the above-mentioned polymer retanning and fatliquor, which comprises: reacting a monomer containing castor oil polyoxyethylene ether with a monomer solution containing acrylic acid in an aqueous phase through free radical graft polymerization to obtain a polymer retanning and fatliquor.

[0035] In some optional embodiments, the method comprises the following steps: using castor oil polyoxyethylene ether, acrylic acid and methacrylic acid as main raw materials, obtaining a polymerization solution by free radical graft polymerization in an aqueous phase under the action of an initiator, and then post-treating the polymerization solution to prepare a polymer retanning and fat-liquoring agent.

[0036] In some optional embodiments, the free radical graft polymerization reaction comprises the following steps: using deionized water as reaction base water, heating the reaction base water to a preset temperature, adding a small amount of mixed monomer solution and initiator solution at one time to perform pre-initiated polymerization, and after the pre-initiated polymerization is completed, simultaneously starting to dropwise add the remaining mixed monomer solution and initiator solution, and after the initiation polymerization is completed, obtaining a polymerization reaction solution;

[0037] Preferably, the ratio of the mass of the bottom water in the reaction to the total mass of the mixed monomers is (1.1-2.0):1, and the heating temperature is 75-95°C;

[0038] Preferably, the polymerization temperature is 75-95° C., the amount of the mixed monomer solution and the initiator solution used for the pre-initiation polymerization is 10-20% of the total amount of the mixed monomer solution and the initiator solution, the pre-initiation reaction time is 10-30 min, and after the remaining mixed monomer solution and the initiator solution are added dropwise, the initiation polymerization reaction time is 1.5-3 h;

[0039] Preferably, the preparation of the mixed monomer solution comprises the following steps: at room temperature, castor oil polyoxyethylene ether, acrylic acid and methacrylic acid are stirred and mixed in a molar ratio of 1:(3-6):(2.2-4), deionized water is added, and the ratio of the mass of deionized water to the total mass of the mixed monomer is (1.5-2.5):1, and the mixture is stirred again for 30 minutes to obtain a mixed monomer solution. Preferably, the castor oil polyoxyethylene ether is at least one of EL-20 and EL-40.

[0040] Preferably, the initiator solution is prepared by taking 0.3-1.5% of the total mass of the mixed monomer initiator and dissolving it in deionized water to prepare an initiator aqueous solution with a mass concentration of 20-30%. Preferably, the initiator is at least one of ammonium persulfate and potassium persulfate.

[0041] In some optional embodiments, the post-treatment comprises the following steps: cooling the polymerization reaction solution, neutralizing it with a neutralizer, and finally adding deionized water to adjust the solid content of the solution to obtain the polymer retanning fatliquor;

[0042] Preferably, the method comprises the following steps: lowering the temperature of the polymerization reaction solution to 55-65° C., then neutralizing with a neutralizer until the pH of the neutralized solution with a solid content of 10% reaches 6.5-7.5, continuing stirring for 15-30 minutes, and finally adding deionized water to adjust the solid content of the solution to 20-25%, thereby obtaining a polymer retanning fatliquor;

[0043] Preferably, the neutralizing agent is at least one of an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide, and the mass concentration of the solution is 20 to 50%.

[0044] In some optional embodiments, the polymer retanning fatliquor has a viscosity of 1400-4000 Pa·s at 40°C.

[0045] In a fourth aspect, an embodiment of the present invention further provides a use of the above-mentioned polymer retanning and fatliquor agent or the polymer retanning and fatliquor agent prepared by the above-mentioned preparation method in leather processing.

[0046] The present invention will be further described below in conjunction with the embodiments.

[0047] Example 1

[0048] Step 1: Prepare a mixed monomer solution. In a 1L three-necked flask with stirring at room temperature, add 178g EL-20, 24g acrylic acid, and 27.5g methacrylic acid in sequence and stir evenly. Then, add 344g deionized water to dilute the monomers and stir at room temperature for 30 minutes to form a uniform mixed monomer solution for standby use.

[0049] Step 2: Prepare an initiator solution. In a 50 mL beaker, dissolve 3.2 g of ammonium persulfate in 7.5 g of deionized water and stir to fully dissolve the solution to obtain an ammonium persulfate aqueous solution for standby use.

[0050] Step 3: Free radical graft polymerization, add 458.6g substrate deionized water to a 2L three-necked flask with stirring, and heat to 80°C. Add 57g mixed monomer solution and 1.06g ammonium persulfate aqueous solution at one time for pre-initiated polymerization. After 10 minutes of pre-initiation, start to drip the remaining mixed monomer solution and initiator solution at the same time. The mixed monomer solution and the initiator solution are dripped in 2.0 hours. After the dripping is completed, react at a temperature of 80°C for 2 hours. After the reaction is completed, the reaction temperature is lowered to 65°C, and then 82g of 32% sodium hydroxide aqueous solution is used for neutralization to pH (10%) to 6.8, and stirring is continued for 15 minutes, and then 170g deionized water is added to adjust the solid content of the product to 20.0%, and a light yellow viscous liquid polymer retanning fatliquor can be obtained, and its viscosity is 1500pa·s (40°C).

[0051] Example 2

[0052] Step 1: Prepare mixed monomers. In a 1L three-necked flask with stirring at room temperature, add 178g EL-20, 43.2g acrylic acid, and 34.4g methacrylic acid in sequence and stir evenly. Then, add 639g deionized water to dilute the monomers and stir at room temperature for 30 minutes to form a uniform mixed monomer for standby use.

[0053] Step 2: Prepare an initiator solution. In a 50 mL beaker, dissolve 2.6 g of potassium persulfate in 7.7 g of deionized water and stir to fully dissolve the potassium persulfate solution to prepare a potassium persulfate aqueous solution for standby use.

[0054] Step 3: Free radical graft polymerization, in a 2L three-necked flask with stirring, add 383.4g substrate deionized water, and heat to 95°C. Add 179g mixed monomer solution and 2.04g ammonium persulfate aqueous solution at one time for pre-initiated polymerization. After 20 minutes of pre-initiation, start to drip the remaining mixed monomer solution and initiator solution at the same time, and the mixed monomer solution and initiator solution are dripped in 3.0 hours. After the dripping is completed, react at a temperature of 95°C for 1.5 hours. After the reaction is completed, the reaction temperature is lowered to 60°C, and then 160g 40% potassium hydroxide aqueous solution is used for neutralization, neutralized to pH (10%) to 7.4, and continued to stir for 30 minutes, and then 143g deionized water is added to adjust the solid content of the product to 20.2%, and a light yellow viscous liquid polymer retanning fatliquor can be obtained, and its viscosity is 2350pa·s (40°C).

[0055] Example 3

[0056] Step 1: Prepare a mixed monomer solution. In a 1L three-necked flask with stirring at room temperature, add 260g EL-40, 32.4g acrylic acid, and 18.62g methacrylic acid in sequence and stir evenly. Then, add 622.64g deionized water to dilute the monomers and stir at room temperature for 30 minutes to form a uniform mixed monomer solution for standby use.

[0057] Step 2: Prepare an initiator solution. In a 50 mL beaker, dissolve 1.2 g of potassium persulfate in 5.1 g of deionized water and stir to fully dissolve the potassium persulfate solution to prepare a potassium persulfate aqueous solution for standby use.

[0058] Step 3: Free radical graft polymerization, add 342.5g substrate deionized water into a 2L three-necked flask with stirring, and heat to 75°C. Add 93.4g mixed monomer solution and 0.62g ammonium persulfate aqueous solution at one time for pre-initiated polymerization. After 30 minutes of pre-initiation, start to drip the remaining monomer solution and initiator solution at the same time, and drip the mixed monomer solution and initiator solution in 2.5 hours. After the dripping is completed, react at a temperature of 75°C for 3 hours. After the reaction is completed, lower the reaction temperature to 55°C, and then neutralize with 53g 50% sodium hydroxide aqueous solution to pH (10%) to 7.1, then add 21.2g deionized water, adjust the solid content of the product to 25.0%, and obtain a light yellow viscous liquid polymer retanning fatliquor with a viscosity of 3980pa·s (40°C).

[0059] Example 4

[0060] Step 1: Prepare a mixed monomer solution. In a 1L three-necked flask with stirring at room temperature, add 260g EL-40, 43.2g acrylic acid, and 25.8g methacrylic acid in sequence and stir evenly. Then, add 526.4g deionized water to dilute the monomers and stir at room temperature for 30 minutes to form a uniform mixed monomer solution for standby use.

[0061] Step 2: Prepare an initiator solution. In a 50 mL beaker, dissolve 4.9 g of ammonium persulfate in 11.5 g of deionized water and stir to fully dissolve the solution to obtain an ammonium persulfate aqueous solution for standby use.

[0062] Step 3: Free radical graft polymerization, add 526.4g substrate deionized water into a 2L three-necked flask with stirring, and heat to 95°C. Add 17.1g mixed monomer solution and 0.33g ammonium persulfate aqueous solution at one time for pre-initiated polymerization. After 10 minutes of pre-initiation, start to drip the remaining mixed monomer solution and initiator solution at the same time. The mixed monomer solution and the initiator solution are dripped in 2 hours. After the dripping is completed, react at a temperature of 95°C for 2.5 hours. After the reaction is completed, the reaction temperature is lowered to 55°C, and then neutralized with 212g 20% ​​sodium hydroxide aqueous solution to a pH (10%) of 6.6. The solid content of the product is 23.2%, and a light yellow viscous liquid polymer retanning fatliquor can be obtained with a viscosity of 1460pa·s (40°C).

[0063] Comparative Example 1

[0064] The steps are similar to those in Example 1, except that sulfated castor oil acrylic resin is used as a retanning fatliquoring agent (prepared with reference to the following literature: Shen Yiding, Li Xiaorui, Zhao Fuzhong, Preparation and structural characterization of amphoteric acrylic resin emulsion [J]. Polymer Materials Science and Engineering, 1992, (1): 30-34).

[0065] Comparative Example 2

[0066] The steps are similar to those in Example 1, except that the epoxy addition number of the castor oil polyoxyethylene ether is 10.

[0067] Comparative Example 3

[0068] The steps are similar to those in Example 1, except that the epoxy addition number of the castor oil polyoxyethylene ether is 60.

[0069] Comparative Example 4

[0070] The steps are similar to those in Example 1, except that the amount of acrylic acid used is 50 g.

[0071] Comparative Example 5

[0072] The steps are similar to those in Example 1, except that the amount of acrylic acid used is 10 g.

[0073] Comparative Example 6

[0074] The steps are similar to those in Example 1, except that the amount of methacrylic acid used is 40 g.

[0075] Comparative Example 7

[0076] The steps are similar to those in Example 1, except that the amount of methacrylic acid used is 15 g.

[0077] Product analysis of polymer retanning fatliquor:

[0078] The first layer of yellow cattle wet blue leather (thickness 1.2mm) was selected as the test object. Figure 1 The application experiment was carried out according to the retanning and fatliquor process operation rules shown in Table 1 using the acrylic resin retanning and fatliquor agent modified with castor oil polyoxyethylene ether prepared in the example.

[0079] The softness, water absorption, air permeability and water-air permeability of the leather blank after retanning and fat-liquoring treatment of the polymer retanning and fat-liquoring agent prepared by the embodiment and the comparative example were tested according to GB / T39371-2020, GB / T4689.21-1996, GB / T4689.22-1996 and QB / T1811-1993. The sensory properties (grain condition, oiliness, fullness and durability of hand feel) of the leather blank were evaluated by three leather experts by manual sensory evaluation (the evaluation level is 1 to 5, the higher the level, the better the performance). The evaluation indexes of the leather blank performance are shown in Table 2.

[0080] Table 1

[0081]

[0082]

[0083] The data obtained from the above test are shown in Table 2.

[0084] Table 2

[0085]

[0086] The application performance evaluation results of the polymer retanning fatliquor emulsion are shown in Table 3 below.

[0087] Table 3

[0088]

[0089] It can be seen from the experimental results in Tables 2 and 3 that when the castor oil polyoxyethylene ether-modified acrylic resin retanning and fat-liquor solution prepared by the embodiment of the present invention is used in the leather retanning and fat-liquor process, it not only has good acid resistance and stability, but also can make the crust leather have good softness, fullness and oiliness. Under the same conditions, when the polymer retanning and fat-liquor prepared in Comparative Example 1 is used in the leather retanning and fat-liquor process, its performance is relatively poor, especially it is not resistant to alkali, acid and electrolyte.

[0090] The data obtained by comparing the above Example 1 and Comparative Examples 2-7 are shown in Table 4.

[0091] Table 4

[0092]

[0093] It can be seen from Table 4 above that when the castor oil polyoxyethylene ether modified acrylic resin retanning and fatliquoring agent solution prepared in the embodiment of the present invention is used in the leather retanning and fatliquoring process, it has good softness, fullness and oiliness.

[0094] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A polymer retanning fatliquor, characterized in that, The raw materials for preparing the polymer retanning fatliquor include castor oil polyoxyethylene ether, and the ethylene oxide addition number in the castor oil polyoxyethylene ether is 20 or 40.

2. The polymer retanning fatliquor according to claim 1, characterized in that The raw materials for preparing the polymer retanning fatliquor include castor oil polyoxyethylene ether, acrylic acid and methacrylic acid, the ethylene oxide addition number in the castor oil polyoxyethylene ether is 20 or 40, and the molar ratio of castor oil polyoxyethylene ether, acrylic acid and methacrylic acid is 1:(3-6):(2.2-4).

3. The polymer retanning fatliquor according to claim 2, characterized in that The main component of the polymer retanning fatliquor is castor oil polyoxyethylene ether-based acrylic resin.

4. The polymer retanning fatliquor according to claim 3, characterized in that The structure of the castor oil polyoxyethylene ether-based acrylic resin is shown in the following formula: Wherein, a represents the degree of polymerization, and the structural formula of R1 is: Wherein, n=x+y+z, n is the average amount of ethylene oxide combined with 1 mol of castor oil, and n is 20 or 40.

5. A method for preparing a polymer retanning fatliquor according to any one of claims 1 to 4, characterized in that: It includes: The monomer containing castor oil polyoxyethylene ether and the monomer solution containing acrylic acid are subjected to free radical graft polymerization reaction in an aqueous phase to prepare a polymer retanning fatliquor.

6. The preparation method according to claim 5, characterized in that: The method comprises the following steps: using castor oil polyoxyethylene ether, acrylic acid and methacrylic acid as main raw materials, obtaining a polymerization solution by free radical graft polymerization in an aqueous phase under the action of an initiator, and then preparing a polymer retanning and fatliquoring agent by post-treatment of the polymerization solution.

7. The preparation method according to claim 6, characterized in that: The free radical graft polymerization reaction comprises the following steps: using deionized water as reaction base water, heating the reaction base water to a preset temperature, adding a small amount of mixed monomer solution and initiator solution at one time to perform pre-initiated polymerization, and after the pre-initiated polymerization is completed, simultaneously starting to dropwise add the remaining mixed monomer solution and initiator solution, and after the initiation polymerization is completed, obtaining a polymerization reaction solution; Preferably, the ratio of the mass of the bottom water in the reaction to the total mass of the mixed monomers is (1.1-2.0):1, and the heating temperature is 75-95°C; Preferably, the polymerization reaction temperature is 75-95° C., the amount of the mixed monomer solution and the initiator solution used for the pre-initiation polymerization is 10-20% of the total amount of the mixed monomer solution and the initiator solution, the pre-initiation reaction time is 10-30 min, and after the remaining mixed monomer solution and the initiator solution are added dropwise, the initiation polymerization reaction time is 1.5-3 h; Preferably, the preparation of the mixed monomer solution comprises the following steps: at room temperature, mixing castor oil polyoxyethylene ether, acrylic acid and methacrylic acid in a molar ratio of 1:(3-6):(2.2-4), adding deionized water, wherein the ratio of the mass of deionized water to the total mass of the mixed monomer is (1.5-2.5):1, and stirring again for 30 minutes to obtain a mixed monomer solution, wherein the castor oil polyoxyethylene ether is preferably at least one of EL-20 and EL-40; Preferably, the initiator solution is prepared by taking 0.3-1.5% of the total mass of the mixed monomer initiator and dissolving it in deionized water to prepare an initiator aqueous solution with a mass concentration of 20-30%. Preferably, the initiator is at least one of ammonium persulfate and potassium persulfate.

8. The preparation method according to claim 6, characterized in that: The post-treatment comprises the following steps: cooling the polymerization reaction solution, neutralizing it with a neutralizing agent, and finally adding deionized water to adjust the solid content of the solution to obtain the polymer retanning fatliquor; Preferably, the method comprises the following steps: lowering the temperature of the polymerization reaction solution to 55-65° C., then neutralizing with a neutralizer until the pH value is 6.5-7.5 when the mass fraction is 10%, continuing stirring for 15-30 minutes, and finally adding deionized water to adjust the solid content of the solution to 20-25%, thereby obtaining a polymer retanning fatliquor; Preferably, the neutralizing agent is at least one of an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide, and the mass concentration of the solution is 20-50%.

9. The preparation method according to claim 8, characterized in that: The viscosity of the polymer retanning fatliquor at 40° C. is 1400-4000 Pa·s.

10. Use of the polymer retanning and fatliquor according to any one of claims 1 to 4 or the polymer retanning and fatliquor prepared by the preparation method according to any one of claims 5 to 9 in leather processing.

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