A preparation method of composite leather fatliquor

Abstract

The invention discloses a preparation method of a composite leather fatliquor, and belongs to the field of chemical synthesis of leather fatliquor. The steps include: vegetable oil, trans-cinnamic acid and an organic solvent are mixed and dissolved to form a reaction solution, and the reaction solution is heated to 70°C~80°C and then an oil-soluble initiator is added for mixed reaction for 1h~2h to obtain a vegetable oil-based polymer; after the vegetable oil-based polymer, amphoteric surfactant and a copper ion-containing solution are mixed, an inorganic base is added to adjust the pH to 8~9 to catalyze chelation for 40min~80min to obtain a copper ion-plant oil-based polymer; copper ion-plant oil-based polymer is catalyzed by a vulcanizing agent to obtain a composite leather fatliquor. The present invention uses vegetable oil containing unsaturated carbon-carbon double bonds as a raw material, and uses trans-cinnamic acid of plant origin, environmentally friendly and fragrant as an odor improver to cover the smell of vegetable oil. After the two react, copper ions are chelated, and then the chelated copper ions are vulcanized and fixed, which solves the problem of easily producing unpleasant odors to greasy raw materials.

Description

Technical Field

[0001] The invention belongs to the field of chemical synthesis of leather fatliquor, and in particular relates to a preparation method of a composite leather fatliquor. Background Art

[0002] Leather products with higher performance have always been the most popular products in leather. At the same time, higher requirements are also put forward for the quality and performance of leather for different purposes. Fatliquor is an auxiliary agent used to lubricate leather fibers and significantly improve leather performance during leather tanning. It is the most widely used leather chemical material in the leather production industry. It is used in large quantities and has many varieties. Fatliquor plays a very important role in the leather industry. To obtain leather with excellent performance, a series of treatment processes are required for the leather, and fatliquor is one of the most important processes for obtaining high-quality leather. Compared with unfatified leather, some properties of the leather obtained by re-fatting the degreased leather, such as softness, fullness and mechanical strength, will be significantly improved, and even some special properties such as anti-oxidation, water resistance, flame retardancy, etc. will be given to the leather. Leather fatliquor can effectively soften the leather, and it is a very important process in leather production. After a series of tanning processes, the grease in the leather is almost completely removed, resulting in a certain degree of reduction in the softness and other properties of the leather. The leather that has just been tanned has a high moisture content and will appear very soft because it has not been dried. However, if it is dried directly at this time, the leather fibers will stick together after losing water because it has not been lubricated with fat, which will cause the leather fibers to shrink and become hard. In the state of the leather being hard and stiff, it is difficult for the leather fibers to absorb water and rewet. During the drying process, due to the lack of proper lubrication between the leather fibers, the fibers are bonded together, causing the leather to become hardened, not resistant to bending, and prone to creases, which cannot meet people's needs for the feel and physical and mechanical properties of leather. Therefore, fatliquoring is an essential process for leather.

[0003] Patent CN108950110A discloses a leather fatliquor and a preparation method thereof. The invention uses modified polyethylene wax emulsion, modified silicone oil emulsion and water as main components. Through the joint action of modified polyethylene wax emulsion and modified silicone oil emulsion, the performance of leather and leather products in various aspects is greatly improved. It has the characteristics of easy emulsification and dispersion, can make the treated leather feel rich and smooth, and does not affect the subsequent coating and dyeing.

[0004] Patent CN113755654A discloses a leather fatliquor and a preparation method thereof. The invention mixes and stirs modified natural oils, antioxidants and salicylic acid to obtain the leather fatliquor. The synergistic effect of salicylic acid on the antioxidant reduces the amount of antioxidant used, reduces the cost of the fatliquor, and increases the anti-oxidation time.

[0005] Patent CN113462826A discloses a cationic leather fatliquor and a preparation method thereof. The invention uses cationic emulsifier, neutral oil, fatty acid glyceride derivative, co-emulsifier, cosolvent, viscosity modifier and organic acid aqueous solution as raw materials, and obtains the cationic leather fatliquor through a series of mixing, heating and stirring, so that the leather has light resistance and oily feel.

[0006] The above patent adjusts the formula of leather fatliquor, and after applying it on leather, the leather has the characteristics of oiliness, anti-oxidation and good hand feel. However, since the core component of leather fatliquor is oil raw materials that provide good permeability and moisturizing effects, most of the oil raw materials are cheap and easily available vegetable oils or animal fats. Such oils have their own pungent odor, which can cause discomfort to people, or even adverse reactions such as vomiting, thereby reducing customers' desire to consume leather products.

[0007] Therefore, improving leather fatliquor to cover up the odor of oily raw materials and make it more pleasant is of great significance to improving the competitiveness of leather products. Summary of the invention

[0008] In view of the deficiencies of the prior art, the present invention uses vegetable oil containing unsaturated carbon-carbon double bonds as raw material, and uses trans-cinnamic acid of plant origin, environmentally friendly and fragrant as an odor improver to mask the odor of the vegetable oil. After the two react, copper ions are chelated, and then the chelated copper ions are vulcanized and fixed to obtain a composite leather fatliquor, which solves the technical problems raised in the background technology. Specifically, the technical solution of the present invention includes the following contents:

[0009] A preparation method of a composite leather fatliquor, the preparation method comprising the following steps:

[0010] The vegetable oil, trans-cinnamic acid and an organic solvent are mixed and dissolved to form a reaction solution, and the reaction solution is heated to 70° C. to 80° C. and then an oil-soluble initiator is added to react for 1 h to 2 h to obtain a vegetable oil-based polymer;

[0011] The vegetable oil-based polymer, the amphoteric surfactant and the copper ion-containing solution are mixed, and then an inorganic base is added to adjust the pH to 8-9 for catalytic chelation for 40 minutes to 80 minutes to obtain the copper ion-vegetable oil-based polymer;

[0012] The copper ion-plant oil-based polymer is catalyzed by a vulcanizing agent to obtain the composite leather fatliquor.

[0013] Furthermore, the iodine value of the vegetable oil is greater than 100.

[0014] Furthermore, the vegetable oil includes soybean oil, linseed oil or sunflower oil.

[0015] Furthermore, the organic solvent includes ethanol or acetone.

[0016] Furthermore, the mass ratio of the vegetable oil: trans-cinnamic acid: organic solvent is 10:1-2:2-5.

[0017] Furthermore, the oil-soluble initiator includes azobisisobutyronitrile, dimethyl azobisisobutyrate or azobisisovaleronitrile.

[0018] Furthermore, the mass ratio of the reaction solution to the oil-soluble initiator is 1:0.02-0.03.

[0019] Furthermore, the amphoteric surfactant includes cocamidopropyl betaine CAB-30 or cocamidopropyl amine oxide CAO-30.

[0020] Furthermore, the copper ion-containing solution includes a copper chloride solution or a copper sulfate solution, and the mass concentration of the copper ion-containing solution is 1% to 1.5%.

[0021] Furthermore, the mass ratio of the plant oil-based polymer: the amphoteric surfactant: the copper ion-containing solution is 1:0.01-0.02:1.

[0022] Furthermore, the inorganic base includes sodium hydroxide or potassium hydroxide.

[0023] Furthermore, the vulcanizing agent includes sodium sulfide or thioacetamide, and the mass of the vulcanizing agent is 0.01 times of the mass of the copper ion-vegetable oil-based polymer.

[0024] Furthermore, the catalytic conditions of the vulcanizing agent include a reaction temperature of 30-40° C. and a reaction time of 50 min-60 min.

[0025] A composite leather fatliquor prepared by a method for preparing a composite leather fatliquor.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The invention uses vegetable oil with unsaturated carbon-carbon double bonds as a raw material and trans-cinnamic acid with fragrance as an odor improver. Under the action of an oil-soluble initiator, a polymerization reaction is initiated at the carbon-carbon double bonds, and then the trans-cinnamic acid is grafted onto the side chain of the vegetable oil carbon chain to obtain a vegetable oil-based polymer. The invention not only improves the pungent odor of the vegetable oil, but also reduces the iodine value of the vegetable oil through the polymerization reaction, so that the softness of the leather after fatliquoring is improved. Then, the plant oil-based polymer is subjected to an alkali treatment, which improves the deprotonation ability of the carboxyl group on the trans-cinnamic acid, helps to chelate the metal ions copper ions, and then forms a complex, fixes the copper ions on the plant oil-based polymer, and then undergoes a vulcanization treatment with a vulcanizing agent, so that the copper ions are vulcanized into a copper sulfide structure with a photothermal antibacterial effect. On the one hand, the stability of the plant oil-based polymer is improved through the chelation of the copper ions, so that the plant oil-based polymer is not easy to atomize; on the other hand, the copper sulfide formed after the copper ions are vulcanized has a good performance of converting light energy into heat energy and then achieving sterilization, so that the composite leather fatting agent of the present invention can use the photothermal effect to achieve an antibacterial effect after fatting the leather, thereby achieving simple daily antibacterial protection for the leather and avoiding the damage to the leather after fatting caused by the additional use of solvents with bactericidal ability such as alcohol. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be clearly and completely described below through the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0029] Unless otherwise specified, the raw materials and reagents used in the present invention are commercially available or can be prepared by known methods.

[0030] Embodiment 1:

[0031] A preparation method of a composite leather fatliquor, specifically comprising the following process:

[0032] 100g soybean oil and 20g ethanol solution were mixed in a three-necked flask and stirred evenly, and then 10g trans-cinnamic acid was added and mixed and stirred until completely dissolved to obtain a reaction solution. The water bath was heated to 70°C for heat preservation, and the reaction solution was placed in a water bath. 2.6g azobisisobutyronitrile was added to the reaction solution at a temperature of 70°C, and the mixture was stirred and reacted for 1 hour. After the reaction was completed, the mixed solution was treated with a 500Da dialysis bag to obtain a soybean oil-based polymer.

[0033] Weigh 50 g of soybean oil-based polymer, 0.5 g of cocamidopropyl betaine CAB-30 and 50 g of 1% copper chloride solution, stir and disperse them evenly, then drop sodium hydroxide to adjust the pH to 8, and then stir and chelate for 40 minutes to obtain copper ion-soybean oil-based polymer.

[0034] Weigh 20 g of copper ion-soybean oil-based polymer and 0.2 g of sodium sulfide, mix and stir, and place in a 30° C. water bath environment to react for 50 minutes to obtain a composite leather fatliquor.

[0035] Embodiment 2:

[0036] A preparation method of a composite leather fatliquor, specifically comprising the following process:

[0037] 100g soybean oil and 20g ethanol solution were mixed in a three-necked flask and stirred evenly, and then 10g trans-cinnamic acid was added and mixed and stirred until completely dissolved to obtain a reaction solution. The water bath was heated to 70°C for heat preservation, and the reaction solution was placed in a water bath. 3.12g azobisisobutyronitrile was added to the reaction solution at a temperature of 70°C, and the mixture was stirred and reacted for 1.2 hours. After the reaction was completed, the mixed solution was treated with a 500Da dialysis bag to obtain a soybean oil-based polymer.

[0038] Weigh 50 g of soybean oil-based polymer, 0.5 g of cocamidopropyl betaine CAB-30 and 50 g of 1.1% copper chloride solution, stir and disperse them evenly, then drop sodium hydroxide to adjust the pH to 8, and then stir and chelate for 40 minutes to obtain copper ion-soybean oil-based polymer.

[0039] Weigh 20 g of copper ion-soybean oil-based polymer and 0.2 g of sodium sulfide, mix and stir, place in a 30° C. water bath environment and react for 52 minutes to obtain a composite leather fatliquor.

[0040] Embodiment 3:

[0041] A preparation method of a composite leather fatliquor, specifically comprising the following process:

[0042] 100g of linseed oil and 30g of ethanol solution were mixed in a three-necked flask and stirred evenly, and then 12g of trans-cinnamic acid was added and mixed and stirred until completely dissolved to obtain a reaction solution. The water bath was heated to 72°C for heat preservation, and the reaction solution was placed in a water bath. 3.55g of azobisisobutyronitrile was added to the reaction solution at a temperature of 72°C, and the mixture was stirred and reacted for 1.2 hours. After the reaction was completed, the mixed solution after the reaction was treated with a 500Da dialysis bag to obtain a linseed oil-based polymer.

[0043] Weigh 50 g of linseed oil-based polymer, 0.6 g of cocamidopropyl betaine CAB-30 and 50 g of 1.2% copper chloride solution, stir and disperse them evenly, then drop sodium hydroxide to adjust the pH to 8.5, and then stir and chelate for 50 minutes to obtain copper ion-linseed oil-based polymer.

[0044] Weigh 20 g of copper ion-linseed oil-based polymer and 0.2 g of sodium sulfide, mix and stir, place in a 32° C. water bath environment and react for 52 minutes to obtain a composite leather fatliquor.

[0045] Embodiment 4:

[0046] A preparation method of a composite leather fatliquor, specifically comprising the following processes:

[0047] 100g of linseed oil and 30g of ethanol solution were mixed in a three-necked flask and stirred evenly, and then 12g of trans-cinnamic acid was added and mixed and stirred until completely dissolved to obtain a reaction solution. The water bath was heated to 72°C for heat preservation, and the reaction solution was placed in a water bath. 3.69g of dimethyl azobisisobutyrate was added to the reaction solution at a temperature of 72°C, and the mixture was stirred and reacted for 1.4h. After the reaction was completed, the mixed solution was treated with a 500Da dialysis bag to obtain a linseed oil-based polymer.

[0048] Weigh 50 g of linseed oil-based polymer, 0.6 g of cocamidopropyl betaine CAB-30 and 50 g of 1.3% copper chloride solution, stir and disperse them evenly, then drop sodium hydroxide to adjust the pH to 8.5, and then stir and chelate for 60 minutes to obtain copper ion-linseed oil-based polymer.

[0049] Weigh 20 g of copper ion-linseed oil-based polymer and 0.2 g of sodium sulfide, mix and stir, and place in a 34° C. water bath environment and react for 54 minutes to obtain a composite leather fatliquor.

[0050] Embodiment 5:

[0051] A preparation method of a composite leather fatliquor, specifically comprising the following processes:

[0052] 100g of linseed oil and 40g of acetone solution were mixed in a three-necked flask and stirred evenly, and then 14g of trans-cinnamic acid was added and stirred until completely dissolved to obtain a reaction solution. The water bath was heated to 74°C for heat preservation, and the reaction solution was placed in a water bath. 4.31g of dimethyl azobisisobutyrate was added to the reaction solution at a temperature of 74°C, and the mixture was stirred and reacted for 1.4h. After the reaction was completed, the mixed solution was treated with a 500Da dialysis bag to obtain a linseed oil-based polymer.

[0053] Weigh 50 g of linseed oil-based polymer, 0.7 g of cocamidopropylamine oxide CAO-30 and 50 g of 1.3% copper sulfate solution, stir and disperse them evenly, then drop potassium hydroxide to adjust the pH to 8.5, and then stir and chelate for 60 minutes to obtain copper ion-linseed oil-based polymer.

[0054] Weigh 20 g of copper ion-linseed oil-based polymer and 0.2 g of thioacetamide, mix and stir, and place in a 34° C. water bath environment to react for 56 minutes to obtain a composite leather fatliquor.

[0055] Embodiment 6:

[0056] A preparation method of a composite leather fatliquor, specifically comprising the following processes:

[0057] 100g of sunflower oil and 40g of acetone solution were mixed in a three-necked flask and stirred evenly, and then 16g of trans-cinnamic acid was added and mixed and stirred until completely dissolved to obtain a reaction solution. The water bath was heated to 76°C for heat preservation, and the reaction solution was placed in a water bath. 4.36g of dimethyl azobisisobutyrate was added to the reaction solution at a temperature of 76°C, and the mixture was stirred and reacted for 1.6 hours. After the reaction was completed, the mixed solution was treated with a 500Da dialysis bag to obtain a sunflower oil-based polymer.

[0058] Weigh 50 g of sunflower oil-based polymer, 0.8 g of cocamidopropylamine oxide CAO-30 and 50 g of copper sulfate solution with a mass concentration of 1.4%, stir and disperse them evenly, then drop potassium hydroxide to adjust the pH to 8.5, and then stir and chelate for 70 minutes to obtain copper ion-sunflower oil-based polymer.

[0059] Weigh 20 g of copper ion-sunflower oil-based polymer and 0.2 g of thioacetamide, mix and stir, and place in a 36° C. water bath environment for a timed reaction of 56 min to obtain a composite leather fatliquor.

[0060] Embodiment 7:

[0061] A preparation method of a composite leather fatliquor, specifically comprising the following processes:

[0062] 100g of sunflower oil and 50g of acetone solution were mixed in a three-necked flask and stirred evenly, and then 18g of trans-cinnamic acid was added and mixed and stirred until completely dissolved to obtain a reaction solution. The water bath was heated to 78°C for insulation, and the reaction solution was placed in a water bath. 5.04g of azobisisovaleronitrile was added to the reaction solution at a temperature of 78°C, and the mixture was stirred and reacted for 1.8h. After the reaction was completed, the mixed solution was treated with a 500Da dialysis bag to obtain a sunflower oil-based polymer.

[0063] Weigh 50 g of sunflower oil-based polymer, 0.9 g of cocamidopropylamine oxide CAO-30 and 50 g of copper sulfate solution with a mass concentration of 1.4%, stir and disperse them evenly, then drop potassium hydroxide to adjust the pH to 9, and then stir and chelate for 70 minutes to obtain copper ion-sunflower oil-based polymer.

[0064] Weigh 20 g of copper ion-sunflower oil-based polymer and 0.2 g of thioacetamide, mix and stir, and place in a 38° C. water bath environment for a timed reaction of 58 min to obtain a composite leather fatliquor.

[0065] Embodiment 8:

[0066] A preparation method of a composite leather fatliquor, specifically comprising the following process:

[0067] 100g of sunflower oil and 50g of acetone solution were mixed in a three-necked flask and stirred evenly, and then 20g of trans-cinnamic acid was added and mixed and stirred until completely dissolved to obtain a reaction solution. The water bath was heated to 80°C for insulation, and the reaction solution was placed in a water bath. 5.1g of azobisisovaleronitrile was added to the reaction solution at 80°C, mixed and stirred, and the reaction was timed for 2h. After the reaction was completed, the mixed solution was treated with a 500Da dialysis bag to obtain a sunflower oil-based polymer.

[0068] Weigh 50 g of sunflower oil-based polymer, 1 g of cocamidopropylamine oxide CAO-30 and 50 g of 1.5% copper sulfate solution, stir and disperse them evenly, then drop potassium hydroxide to adjust the pH to 9, then stir and chelate for 80 minutes to obtain copper ion-sunflower oil-based polymer.

[0069] Weigh 20 g of copper ion-sunflower oil-based polymer and 0.2 g of thioacetamide, mix and stir, and place in a 40° C. water bath environment for a timed reaction of 60 min to obtain a composite leather fatliquor.

[0070] Comparative Example 1:

[0071] A preparation method of a composite leather fatliquor, specifically comprising the following process:

[0072] The sunflower seed oil in Example 8 was replaced by olive oil, and the other conditions remained the same as in Example 8.

[0073] Comparative Example 2:

[0074] A preparation method of a composite leather fatliquor, specifically comprising the following process:

[0075] The sunflower seed oil in Example 8 was replaced by palm oil, and the other conditions remained the same as in Example 8.

[0076] Comparative Example 3:

[0077] A preparation method of a composite leather fatliquor, specifically comprising the following processes:

[0078] The azobisisovaleronitrile in Example 8 was replaced with a hydrogen peroxide solution with a mass concentration of 30%, and the other conditions remained the same as in Example 8.

[0079] Comparative Example 4:

[0080] A preparation method of a composite leather fatliquor, specifically comprising the following processes:

[0081] The azobisisovaleronitrile in Example 8 was replaced with a hydrogen peroxide solution with a mass concentration of 50%, and the other conditions were kept consistent with Example 8.

[0082] Comparative Example 5:

[0083] A preparation method of a composite leather fatliquor, specifically comprising the following processes:

[0084] 100g of sunflower oil and 50g of acetone solution were mixed in a three-necked flask and stirred evenly, and then 20g of trans-cinnamic acid was added and mixed and stirred until completely dissolved to obtain a reaction solution. The water bath was heated to 80°C for insulation, and the reaction solution was placed in a water bath. 5.1g of azobisisovaleronitrile was added to the reaction solution at 80°C, and the mixture was stirred and reacted for 2 hours. After the reaction was completed, the mixed solution was treated with a 500Da dialysis bag, and the obtained sunflower oil-based polymer was directly used as a composite leather fatliquor.

[0085] Comparative Example 6:

[0086] A preparation method of a composite leather fatliquor, specifically comprising the following processes:

[0087] The copper sulfate solution with a mass concentration of 1.5% in Example 8 was replaced by a copper sulfate solution with a mass concentration of 2%, and the other conditions remained the same as in Example 8.

[0088] The surface tension of the composite leather fatliquor obtained in Examples 1 to 8 and Comparative Examples 1 to 6 was measured by a surface tension meter, and the presence of fragrance and the duration of the fragrance were determined by manual sniffing. The results are shown in the following table:

[0089]

[0090] From the above data, we can see that:

[0091] (1) It can be seen from Examples 1 to 8 that the composite leather fatliquor obtained by the present invention has low surface tension, good dispersibility, and is conducive to leather absorption.

[0092] (2) It can be seen from Comparative Examples 1-2 and Example 8 that the iodine value of olive oil and palm oil is relatively low. Although the double bonds are reduced after the polymerization reaction, the low iodine value of olive oil and palm oil leads to a low proportion of unsaturated fatty acids and a high proportion of saturated fatty acids. The interaction between saturated fatty acid molecules is relatively strong, which leads to an increase in the intermolecular binding force, thereby increasing the surface tension and poor dispersibility, which is not conducive to the leather absorbing the composite leather fatliquor. In addition, due to the low proportion of unsaturated fatty acids, less trans-cinnamic acid is introduced by polymerization, resulting in a weaker fragrance and a shorter duration.

[0093] (3) It can be seen from Comparative Examples 3-4 and Example 8 that a lower concentration of hydrogen peroxide is poorly soluble in the vegetable oil-based polymer, resulting in a poor catalytic effect and almost no change in the surface tension, while a higher concentration of hydrogen peroxide increases the contact area with the vegetable oil-based polymer, which is beneficial to reducing the surface tension.

[0094] (4) It can be seen from Comparative Example 5 and Example 8 that the chelation of metal ions can reduce the surface tension. In the absence of metal ion chelation, the surface tension improvement is poor.

[0095] (6) It can be seen from Comparative Example 6 and Example 8 that increasing the concentration of copper ions can increase the metal chelating strength. Too high a metal chelating strength can make the composite leather fatliquor have poor fluidity and difficult to disperse.

[0096] The cowhide leather is treated according to the following fatliquoring process:

[0097] Fatliquoring process:

[0098] Softening: 200% water + 0.3% Pingping, 40℃, 120min;

[0099] Washing: 200% water, 40℃ for 30min, drain;

[0100] Retanning: 200% water + 0.5% formic acid, 30°C for 30 minutes, 4% chrome powder, 60 minutes, 0.5% sodium formate + 0.5% baking soda, 30 minutes;

[0101] Water washing: 200% water treatment for 30 minutes, drain;

[0102] Neutralization: 200% water + 2.5% sodium formate + 0.8% baking soda, treatment for 90 minutes;

[0103] Fatting: 10% of the composite leather fatliquor obtained in Examples 1 to 8 and Comparative Examples 1 to 6 was treated at 50° C. for 60 min;

[0104] Water washing: 200% water, 30 minutes of treatment and drainage;

[0105] Dry and soften.

[0106] Then, the tensile strength was measured according to "QB / T 1269-2012 Physical and Mechanical Tests for Fur - Determination of Tensile Strength and Elongation", the softness after fatliquoring was measured according to "GB / T 39371-2020 Physical and Mechanical Tests for Leather - Determination of Softness", and the atomization value was measured according to "QB / T 2728-2018 Physical and Mechanical Tests for Leather - Determination of Atomization Performance". The results are shown in the following table:

[0107]

[0108] From the above data, we can know that:

[0109] (1) It can be seen from Examples 1 to 8 that the composite leather fatliquor prepared by the present invention has a good odor effect and a strong fragrance retention ability after being applied to leather, and improves the softness and tensile strength of the leather and reduces the atomization value.

[0110] (2) It can be seen from Comparative Examples 1 to 6 that although there is a certain fragrance, there is no good fragrance retention ability, and the tensile strength and softness of Comparative Examples 1 to 5 are poor. The high atomization value makes the composite leather fatliquor easily affected by temperature and migrates out, affecting the protection of the fatliquor to the leather. In addition, the hydrogen peroxide solution used in Comparative Examples 3 and 4 has poor compatibility with vegetable oil, and the amount of organic solvent added is small. After the two are mixed, the effective contact surface is low, and the catalytic effect is poor. Further increasing the concentration of hydrogen peroxide, although hydrogen peroxide has the ability to catalyze the formation of free radicals and then initiate polymerization, due to the strong oxidizing property of hydrogen peroxide, the unsaturated carbon-carbon double bond is easily oxidized to form an epoxy structure, which increases the difficulty of introducing trans-cinnamic acid into the side chain of vegetable oil, resulting in poor fragrance modification effect; Comparative Example 6 increases the copper ion concentration, which enhances the metal chelation effect and tensile strength, but the excessively high copper ion concentration makes the leather after fatliquor extremely soft, affecting the comfort, and is easily damaged and cracked.

[0111] The fat-liquored leather was placed in an environment at a temperature of 20°C for 30 minutes, and then irradiated with a 1064nm NIR laser for 20 minutes. The temperature of the leather surface before and after the laser irradiation treatment was recorded. The results are shown in the following table:

[0112]

[0113] The above-described embodiments provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected.

Claims

1. A method for preparing a composite leather fatliquor, characterized in that, The preparation method comprises the following steps: The vegetable oil, trans-cinnamic acid and an organic solvent are mixed and dissolved to form a reaction solution, the reaction solution is heated to 70° C. to 80° C., an oil-soluble initiator is added, and the mixture is reacted for 1 h to 2 h to obtain a vegetable oil-based polymer; The vegetable oil-based polymer, the amphoteric surfactant and the copper ion-containing solution are mixed, and then an inorganic base is added to adjust the pH to 8-9 for catalytic chelation for 40 minutes to 80 minutes to obtain the copper ion-vegetable oil-based polymer; The copper ion-plant oil-based polymer is catalyzed by a vulcanizing agent to obtain the composite leather fatliquor; The vegetable oil is soybean oil, linseed oil or sunflower oil; The copper ion solution is a copper chloride solution or a copper sulfate solution, and the mass concentration of the copper ion solution is 1% to 1.5%; The mass ratio of the vegetable oil-based polymer: the amphoteric surfactant: the copper ion-containing solution is 1:0.01-0.02:

1.

2. The method for preparing a composite leather fatliquor according to claim 1, wherein The mass ratio of the vegetable oil: trans-cinnamic acid: organic solvent is 10:1-2:2-5.

3. The preparation method of a composite leather fatliquor according to claim 1, characterized in that, The oil-soluble initiator is azobisisobutyronitrile, dimethyl azobisisobutyrate or azobisisovaleronitrile.

4. The preparation method of a composite leather fatliquor according to claim 1, characterized in that, The mass ratio of the reaction liquid to the oil-soluble initiator is 1:0.02-0.

03.

5. The preparation method of a composite leather fatliquor according to claim 1, characterized in that, The amphoteric surfactant is cocamidopropyl betaine CAB-30 or cocamidopropyl amine oxide CAO-30.

6. The preparation method of a composite leather fatliquor according to claim 1, characterized in that: The vulcanizing agent is sodium sulfide or thioacetamide, and the mass of the vulcanizing agent is 0.01 times of the mass of the copper ion-vegetable oil-based polymer.

7. The method for preparing a composite leather fatliquor according to claim 1, characterized in that: The conditions for the catalysis of the vulcanizing agent include a reaction temperature of 30-40° C. and a reaction time of 50-60 min.

8. A composite leather fatliquor prepared by the preparation method of a composite leather fatliquor according to any one of claims 1 to 7.

Images