Aged leather softening agent based on lanolin / soybean polysaccharide as well as preparation method and application of aged leather softening agent

Abstract

The invention belongs to the technical field of leather softening agents, and particularly relates to an aged leather softening agent based on wool fat / soybean polysaccharide as well as a preparation method and application of the aged leather softening agent. The softening agent is prepared by mixing glycerol, amino silicon oil, wool fat and a soybean polysaccharide aqueous solution. The preparation method of the softening agent comprises the following steps: mixing a soybean polysaccharide aqueous solution with glycerol to obtain a first mixture; adding amino silicon oil into the first mixture, and mixing to obtain a second mixture; and adding molten wool fat into the second mixture, and mixing to obtain the aged leather softening agent based on wool fat / soybean polysaccharide. The lanolin / soybean polysaccharide-based aged leather softening agent is prepared from pure natural soybean polysaccharide, glycerol, amino silicon oil and lanolin, so that deep penetration of aged leather and effective filling of fiber gaps are realized, and the softness, color and luster and heat resistance of the aged leather can be remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of leather softening agents, and in particular relates to an aged leather softening agent based on lanolin / soybean polysaccharide, and a preparation method and application thereof. Background Art

[0002] As an important material in human history, leather is not only widely used in daily life, but also an important carrier of culture, history and art. Leather artifacts, especially ancient leather products, have become an important part of cultural heritage due to their unique artistic and historical value. However, with the passage of time, these precious leather artifacts have experienced varying degrees of aging due to the natural environment, human factors and improper protection, such as loss of gloss, decreased softness, hardening and brittleness. These changes not only affect the aesthetics of leather artifacts, but also bring great challenges to their preservation and display.

[0003] Traditional leather softening methods mainly rely on oils and chemicals. Although they can restore the softness of leather, long-term use of these chemicals will cause secondary damage to the leather and even have adverse effects on the environment and human health. In recent years, with the continuous development of science and technology, researchers have modified lecithin, lanolin and castor oil to produce a variety of composite fatliquors. Although these composite fatliquors can improve the softness of leather, the modified composite fatliquors are irreversible and will cause secondary damage to crusted leather cultural relics, while limiting the possibility of further protection and research on leather cultural relics. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides an aged leather softening agent based on lanolin / soybean polysaccharide, and a preparation method and application thereof. The present invention adopts pure natural soybean polysaccharide, glycerin, amino silicone oil and lanolin to prepare the aged leather softening agent based on lanolin / soybean polysaccharide, which not only achieves deep penetration into the aged leather and effective filling of fiber gaps, but also can significantly improve the softness, color and heat resistance of the aged leather, and provides scientific theoretical guidance for the softening, long-term preservation and display of aged leather cultural relics.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The first object of the present invention is to provide an aged leather softening agent based on lanolin / soybean polysaccharide, wherein the softening agent is prepared by mixing glycerin, amino silicone oil, lanolin and soybean polysaccharide aqueous solution, and the mass ratio of glycerin, amino silicone oil, lanolin and soybean polysaccharide aqueous solution is 2:1:1:10-25;

[0007] Among them, the mass percentage of the soybean polysaccharide aqueous solution is 3wt% to 5wt%. When the mass percentage of the soybean polysaccharide aqueous solution is less than 3wt%, the emulsion is stratified; when the mass percentage of the soybean polysaccharide aqueous solution is greater than 5wt%, the emulsion particle size becomes larger, and when the mass percentage of the soybean polysaccharide aqueous solution is greater than 5wt%, the soybean polysaccharide is difficult to dissolve.

[0008] The second object of the present invention is to provide a method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide, which is prepared according to the following steps:

[0009] S1, mixing the soybean polysaccharide aqueous solution and glycerol to obtain a first mixture;

[0010] S2, adding amino silicone oil to the first mixture, mixing, to obtain a second mixture;

[0011] S3, adding the heated and melted lanolin to the second mixture, and mixing them to obtain an aged leather softening agent based on lanolin / soybean polysaccharide.

[0012] Preferably, in step S1, the mixing temperature is 50°C to 60°C, the mixing time is 15 min to 30 min, and the rotation speed is 1500 r / min.

[0013] Preferably, in step S2, the mixing temperature is 50°C to 60°C, the mixing time is 15 min to 30 min, and the rotation speed is 1500 r / min.

[0014] Preferably, in step S3, the mixing temperature is 50°C to 60°C, the mixing time is 150min to 180min, and the rotation speed is 1500r / min.

[0015] The third object of the present invention is to provide the application of the above-mentioned aged leather softening agent based on lanolin / soybean polysaccharide in the softening of aged leather, which is carried out according to the following steps:

[0016] Apply the aged leather softening agent based on lanolin / soybean polysaccharide to the aged leather surface and let it dry.

[0017] Preferably, the aged leather softening agent based on lanolin / soybean polysaccharide is repeatedly applied to the aged leather surface, and then applied again after the aged leather has completely absorbed the agent, until the quality of the aged leather does not change, with an interval of 20 minutes between each application.

[0018] Preferably, before applying the aged leather softening agent based on lanolin / soy polysaccharide, the aged leather is first moistened with distilled water so that the water molecules can penetrate into the fiber structure of the aged leather, making the aged leather fibers more swollen and soft, thereby facilitating the subsequent penetration and uniform distribution of the aged leather softening agent based on lanolin / soy polysaccharide.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention provides an aged leather softening agent based on lanolin / soybean polysaccharide, which is prepared by using pure natural soybean polysaccharide, glycerol, amino silicone oil and lanolin. The aged leather softening agent based on lanolin / soybean polysaccharide of the present invention not only avoids the negative effects caused by chemical modification, but also utilizes the natural properties of soybean polysaccharide, glycerol, amino silicone oil and lanolin to achieve deep penetration into aged leather and effective filling of fiber gaps, which can significantly improve the softness, color and heat resistance of aged leather.

[0021] Among them, glycerol and soybean polysaccharides both contain hydroxyl groups, and there are a large number of polar groups such as -OH and -COOH on the collagen molecules in aged leather. When glycerol and soybean polysaccharides are filled into the aged leather fiber network, they form hydrogen bonds with the collagen molecules, thereby significantly enhancing its heat resistance and providing an ideal environmentally friendly solution for the care of aged leather.

[0022] 2. The present invention provides a method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide, comprising mixing an aqueous soybean polysaccharide solution and glycerin to obtain a first mixture, then adding amino silicone oil to the first mixture to obtain a second mixture, and finally adding melted lanolin to the second mixture and mixing to obtain an aged leather softening agent based on lanolin / soybean polysaccharide.

[0023] Among them, soybean polysaccharide has emulsifying and filling effects, glycerol serves as a humectant, amino silicone oil serves as a softener, and lanolin serves as a fatting agent. In the present invention, a soybean polysaccharide aqueous solution, glycerol, amino silicone oil and lanolin are mixed to form an oil-in-water emulsion, and the emulsifying and filling effects of soybean polysaccharide and the moisturizing property of glycerol cooperate with each other to ensure the uniform dispersion and stability of each component during the mixing process, while improving the moisturizing property of the aged leather softening agent based on lanolin / soybean polysaccharide; and amino silicone oil serves as a softener, and its permeability and the property of reducing friction resistance between fibers cooperate with the moisturizing and moisturizing properties of lanolin, which not only enhances the softness and smoothness of the aged leather softening agent based on lanolin / soybean polysaccharide on aged leather fibers, but also improves the overall softness and color of the aged leather.

[0024] 3. The present invention also provides the use of an aged leather softening agent based on lanolin / soy polysaccharide in softening aged leather. The aged leather softening agent based on lanolin / soy polysaccharide can effectively alleviate the hardening phenomenon of aged leather, significantly improve its softness and elasticity, and achieve efficient softening while maintaining the appearance quality of the aged leather. In addition, it can also enhance the thermal stability of aged leather and further promote the recovery of the elasticity of aged leather, providing an efficient and practical solution for the repair and maintenance of aged leather. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a particle size distribution diagram of the soybean polysaccharide aqueous solution used in Examples 4 to 6 of the present invention;

[0026] Figure 2 This is an infrared spectrum of soybean polysaccharides used in Examples 1 to 6 and Comparative Examples 1 to 3 of the present invention;

[0027] Figure 3The optical microscope photographs and particle size distribution diagrams of the aged leather softening agent based on lanolin / soy polysaccharide of Examples 1 to 6 and Comparative Examples 2 to 3 are shown, wherein (a) is an optical microscope photograph of the aged leather softening agent based on lanolin / soy polysaccharide of Example 1, (a1) is a particle size distribution diagram of the aged leather softening agent based on lanolin / soy polysaccharide of Example 1, and (a2) is an emulsion diagram of the aged leather softening agent based on lanolin / soy polysaccharide of Example 1; (b) is an optical microscope photograph of the aged leather softening agent based on lanolin / soy polysaccharide of Example 2, and (b1) is a particle size distribution diagram of the aged leather softening agent based on lanolin / soy polysaccharide of Example 2. The particle size distribution diagram of the softening agent, (b2) is the emulsion diagram of the aged leather softening agent based on lanolin / soy polysaccharide in Example 2; (c) is the optical microscope photo of the aged leather softening agent based on lanolin / soy polysaccharide in Example 3, (c1) is the particle size distribution diagram of the aged leather softening agent based on lanolin / soy polysaccharide in Example 3, (c2) is the emulsion diagram of the aged leather softening agent based on lanolin / soy polysaccharide in Example 3; (d) is the optical microscope photo of the aged leather softening agent based on lanolin / soy polysaccharide in Example 4, (d1) is the particle size distribution diagram of the aged leather softening agent based on lanolin / soy polysaccharide in Example 4, (d2) (e) is an optical microscope photograph of the aged leather softening agent based on lanolin / soy polysaccharide in Example 5, (e1) is a particle size distribution diagram of the aged leather softening agent based on lanolin / soy polysaccharide in Example 5, and (e2) is an emulsion photograph of the aged leather softening agent based on lanolin / soy polysaccharide in Example 5; (f) is an optical microscope photograph of the aged leather softening agent based on lanolin / soy polysaccharide in Example 6, (f1) is a particle size distribution diagram of the aged leather softening agent based on lanolin / soy polysaccharide in Example 6, and (f2) is an emulsion photograph of the aged leather softening agent based on lanolin / soy polysaccharide in Example 6. (g) is an optical microscope photograph of the aged leather softening agent based on lanolin / soy polysaccharides in comparative example 2, (g1) is a particle size distribution diagram of the aged leather softening agent based on lanolin / soy polysaccharides in comparative example 2, and (g2) is an emulsion photograph of the aged leather softening agent based on lanolin / soy polysaccharides in comparative example 2; (h) is an optical microscope photograph of the aged leather softening agent based on lanolin / soy polysaccharides in comparative example 3, (h1) is a particle size distribution diagram of the aged leather softening agent based on lanolin / soy polysaccharides in comparative example 3, and (h2) is an emulsion photograph of the aged leather softening agent based on lanolin / soy polysaccharides in comparative example 3.

[0028] Figure 4The present invention provides a comparison of the softness of aged rubber-tanned leather samples before and after softening by the aged leather softening agent based on lanolin / soy polysaccharide of Examples 1 to 6 of the present invention, wherein (a) is a comparison of the softness of aged rubber-tanned leather samples before and after softening by the aged leather softening agent based on lanolin / soy polysaccharide of Examples 1, 2 and 3, and (b) is a comparison of the softness of aged rubber-tanned leather samples before and after softening by the aged leather softening agent based on lanolin / soy polysaccharide of Examples 4, 5 and 6;

[0029] Figure 5 These are digital photographs of aged rubber-tanned leather samples before and after softening by the aged leather softening agent based on lanolin / soybean polysaccharide of Examples 1 to 6 of the present invention;

[0030] Figure 6 The chromatic aberration analysis diagram of the aged leather softening agent based on lanolin / soy polysaccharide prepared in Examples 1 to 6 of the present invention before and after the softening of the aged rubber-tanned leather sample, wherein (a) is a chromatic aberration analysis diagram of the aged rubber-tanned leather sample before and after the softening of the aged leather softening agent based on lanolin / soy polysaccharide applied in Examples 1, 2 and 3, and (b) is a chromatic aberration analysis diagram of the aged rubber-tanned leather sample before and after the softening of the aged leather softening agent based on lanolin / soy polysaccharide applied in Examples 4, 5 and 6;

[0031] Figure 7 Thermogravimetric (TG) and differential thermogravimetric (DTG) curves of the aged leather softening agent based on lanolin / soy polysaccharide prepared in Examples 1 to 6 of the present invention before and after the softening of the aged rubber-tanned leather sample, wherein (a) is the TG / DTG curve of the aged rubber-tanned leather sample before and after the softening of the aged leather softening agent based on lanolin / soy polysaccharide in Example 1, (b) is the TG / DTG curve of the aged rubber-tanned leather sample before and after the softening of the aged leather softening agent based on lanolin / soy polysaccharide in Example 2, and (c) is the TG / DTG curve of the aged rubber-tanned leather sample before and after the softening of the aged leather softening agent based on lanolin / soy polysaccharide in Example 2. Example 3 is a TG / DTG curve of the aged leather softening agent based on lanolin / soy polysaccharide before and after softening, (d) is a TG / DTG curve of the aged rubber tanned leather sample application example 4 based on lanolin / soy polysaccharide before and after softening, (e) is a TG / DTG curve of the aged rubber tanned leather sample application example 5 based on lanolin / soy polysaccharide before and after softening, (f) is a TG / DTG curve of the aged rubber tanned leather sample application example 6 based on lanolin / soy polysaccharide before and after softening;

[0032] Figure 8The present invention provides DSC graphs of aged rubber-tanned leather samples before and after softening using the lanolin / soybean polysaccharide-based aged leather softening agent prepared in Examples 1 to 6 of the present invention, wherein (a) is a DSC graph of the aged rubber-tanned leather sample before and after softening using the softening agent in Example 1, (b) is a DSC graph of the aged rubber-tanned leather sample before and after softening using the softening agent in Example 2, (c) is a DSC graph of the aged rubber-tanned leather sample before and after softening using the softening agent in Example 3, (d) is a DSC graph of the aged rubber-tanned leather sample before and after softening using the softening agent in Example 4, (e) is a DSC graph of the aged rubber-tanned leather sample before and after softening using the softening agent in Example 5, and (f) is a DSC graph of the aged rubber-tanned leather sample before and after softening using the softening agent in Example 6. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solution of the present invention in combination with the data in 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 ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specifically stated, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0035] In the prior art, composite fatliquor is mainly prepared by chemically modifying lecithin, lanolin and castor oil. This modification process changes the original chemical structure of the natural ingredients, which will cause irreversible damage to leather cultural relics during use. At the same time, it limits the possibility of further protection and research on leather cultural relics, and also limits its application in the protection of crusted leather cultural relics.

[0036] In view of these defects, the present invention provides an aged leather softening agent based on lanolin / soybean polysaccharide, wherein the softening agent is a mixture of glycerin, aminosilicone oil, lanolin and soybean polysaccharide aqueous solution, and the mass ratio of glycerin, aminosilicone oil, lanolin and soybean polysaccharide aqueous solution is 2:1:1:10-25; wherein the mass percentage of soybean polysaccharide aqueous solution is 3wt%-5wt%. The present invention prepares the aged leather softening agent by mixing the soybean polysaccharide aqueous solution with emulsifying properties with glycerin, introducing aminosilicone oil as a softener, and combining the moisturizing and hydrating properties of lanolin. This method avoids the negative effects of chemical modification, and at the same time utilizes the natural properties of soybean polysaccharides, glycerin, aminosilicone oil and lanolin, achieving deep penetration into aged leather and effective filling of fiber gaps, significantly improving the softness, color and heat resistance of leather.

[0037] The technical solution of the present invention is further explained by using embodiments below, which are specifically as follows:

[0038] Example 1

[0039] A method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide comprises the following steps:

[0040] S1. According to the mass ratio of glycerol, amino silicone oil, lanolin and 3wt% soybean polysaccharide aqueous solution of 2:1:1:10, glycerol, amino silicone oil, lanolin and soybean polysaccharide aqueous solution are weighed respectively for later use;

[0041] S2, adding the weighed 3wt% soybean polysaccharide aqueous solution and glycerol into a three-necked flask, placing the three-necked flask in a 60°C constant temperature water bath, and using an overhead stirrer to stir at a speed of 1500r / min for 30min to obtain a first mixture;

[0042] S3, adding the weighed amino silicone oil to the first mixture, and continuing to stir at a speed of 1500 r / min for 30 min in a constant temperature water bath at 60° C. to obtain a second mixture;

[0043] S4. Dissolve the weighed lanolin at 60°C and add it dropwise into the second mixture. Use a digital high-speed disperser homogenizer to shear at 10,000 r / min for 5 minutes. Then transfer it to a three-necked flask and heat it in a 60°C water bath. Use an overhead stirrer to mechanically stir at 1,500 r / min for 3 hours to obtain 1# lanolin / soybean polysaccharide-based aged leather softening agent.

[0044] Example 2

[0045] A method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide is the same as steps S2-S4 of Example 1, except that the mass ratio of glycerol, amino silicone oil, lanolin and 3wt% soybean polysaccharide aqueous solution in S1 is 2:1:1:15, comprising the following steps:

[0046] S1. According to the mass ratio of glycerol, amino silicone oil, lanolin and 3 wt% soybean polysaccharide aqueous solution of 2:1:1:15, glycerol, amino silicone oil, lanolin and soybean polysaccharide aqueous solution are weighed respectively for later use;

[0047] S2, adding the weighed 3wt% soybean polysaccharide aqueous solution and glycerol into a three-necked flask, placing the three-necked flask in a 60°C constant temperature water bath, and using an overhead stirrer to stir at a speed of 1500r / min for 30min to obtain a first mixture;

[0048] S3, adding the weighed amino silicone oil to the first mixture, and continuing to stir at a speed of 1500 r / min for 30 min in a constant temperature water bath at 60° C. to obtain a second mixture;

[0049] S4. Dissolve the weighed lanolin at 60°C and add it dropwise into the second mixture. Use a digital high-speed disperser homogenizer to shear at 10,000 r / min for 5 minutes. Then transfer it to a three-necked flask and heat it in a 60°C water bath. Use an overhead stirrer to mechanically stir at 1,500 r / min for 3 hours to obtain 2# lanolin / soybean polysaccharide-based aged leather softening agent.

[0050] Example 3

[0051] A method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide is the same as steps S2-S4 of Example 1, except that the mass ratio of glycerol, amino silicone oil, lanolin and 3wt% soybean polysaccharide aqueous solution in S1 is 2:1:1:20, comprising the following steps:

[0052] S1. According to the mass ratio of glycerol, amino silicone oil, lanolin and 3wt% soybean polysaccharide aqueous solution of 2:1:1:20, glycerol, amino silicone oil, lanolin and soybean polysaccharide aqueous solution are weighed respectively for later use;

[0053] S2, adding the weighed 3wt% soybean polysaccharide aqueous solution and glycerol into a three-necked flask, placing the three-necked flask in a 60°C constant temperature water bath, and using an overhead stirrer to stir at a speed of 1500r / min for 30min to obtain a first mixture;

[0054] S3, adding the weighed amino silicone oil to the first mixture, and continuing to stir at a speed of 1500 r / min for 30 min in a constant temperature water bath at 60° C. to obtain a second mixture;

[0055] S4. Dissolve the weighed lanolin at 60°C and add it dropwise into the second mixture. Use a digital high-speed disperser homogenizer to shear at 10,000 r / min for 5 minutes. Then transfer it to a three-necked flask and heat it in a 60°C water bath. Use an overhead stirrer to mechanically stir at 1,500 r / min for 3 hours to obtain 3# lanolin / soybean polysaccharide-based aged leather softening agent.

[0056] Example 4

[0057] A method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide, which has the same preparation steps as those in Example 1, except that the mass percentage of the soybean polysaccharide aqueous solution is replaced by 5wt% from 3wt%, and comprises the following steps:

[0058] S1. According to the mass ratio of glycerol, amino silicone oil, lanolin and 3wt% soybean polysaccharide aqueous solution of 2:1:1:10, glycerol, amino silicone oil, lanolin and soybean polysaccharide aqueous solution are weighed respectively for later use;

[0059] S2, adding the weighed 5 wt% soybean polysaccharide aqueous solution and glycerol into a three-necked flask, placing the three-necked flask in a 60° C. constant temperature water bath, and using an overhead stirrer to stir at a speed of 1500 r / min for 30 min to obtain a first mixture;

[0060] S3, adding the weighed amino silicone oil to the first mixture, and continuing to stir at a speed of 1500 r / min for 30 min in a constant temperature water bath at 60° C. to obtain a second mixture;

[0061] S4. Dissolve the weighed lanolin at 60°C and add it dropwise into the second mixture. Use a digital high-speed disperser homogenizer to shear at 10,000 r / min for 5 minutes. Then transfer it to a three-necked flask and heat it in a 60°C water bath. Use an overhead stirrer to mechanically stir at 1,500 r / min for 3 hours to obtain 4# aged leather softening agent based on lanolin / soybean polysaccharide.

[0062] Example 5

[0063] A method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide, which has the same preparation steps as those in Example 2, except that the mass percentage of the soybean polysaccharide aqueous solution is replaced by 5wt% from 3wt%, and comprises the following steps:

[0064] S1. According to the mass ratio of glycerol, amino silicone oil, lanolin and 3 wt% soybean polysaccharide aqueous solution of 2:1:1:15, glycerol, amino silicone oil, lanolin and soybean polysaccharide aqueous solution are weighed respectively for later use;

[0065] S2, adding the weighed 5 wt% soybean polysaccharide aqueous solution and glycerol into a three-necked flask, placing the three-necked flask in a 60° C. constant temperature water bath, and using an overhead stirrer to stir at a speed of 1500 r / min for 30 min to obtain a first mixture;

[0066] S3, adding the weighed amino silicone oil to the first mixture, and continuing to stir at a speed of 1500 r / min for 30 min in a constant temperature water bath at 60° C. to obtain a second mixture;

[0067] S4. Dissolve the weighed lanolin at 60°C and add it dropwise into the second mixture. Use a digital high-speed disperser homogenizer to shear at 10,000 r / min for 5 minutes. Then transfer it to a three-necked flask and heat it in a 60°C water bath. Use an overhead stirrer to mechanically stir at 1,500 r / min for 3 hours to obtain 5# aged leather softening agent based on lanolin / soybean polysaccharide.

[0068] Example 6

[0069] A method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide, which has the same preparation steps as those in Example 3, except that the mass percentage of the soybean polysaccharide aqueous solution is replaced by 5wt% from 3wt%, and comprises the following steps:

[0070] S1. According to the mass ratio of glycerol, amino silicone oil, lanolin and 5wt% soybean polysaccharide aqueous solution of 2:1:1:20, glycerol, amino silicone oil, lanolin and soybean polysaccharide aqueous solution are weighed respectively for later use;

[0071] S2, adding the weighed 3wt% soybean polysaccharide aqueous solution and glycerol into a three-necked flask, placing the three-necked flask in a 60°C constant temperature water bath, and using an overhead stirrer to stir at a speed of 1500r / min for 30min to obtain a first mixture;

[0072] S3, adding the weighed amino silicone oil to the first mixture, and continuing to stir at a speed of 1500 r / min for 30 min in a constant temperature water bath at 60° C. to obtain a second mixture;

[0073] S4. Dissolve the weighed lanolin at 60°C and add it dropwise into the second mixture. Use a digital high-speed disperser homogenizer to shear at 10,000 r / min for 5 minutes. Then transfer it to a three-necked flask and heat it in a 60°C water bath. Use an overhead stirrer to mechanically stir at 1,500 r / min for 3 hours to obtain 6# lanolin / soybean polysaccharide-based aged leather softening agent.

[0074] Example 7

[0075] A method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide, which has the same preparation steps as those in Example 4, except that the mass ratio of glycerol, amino silicone oil, lanolin and 3wt% soybean polysaccharide aqueous solution in S1 is 2:1:1:25, and the mixing temperature of S2, S3 and S4 is replaced from 60°C to 50°C, comprising the following steps:

[0076] S1. According to the mass ratio of glycerol, amino silicone oil, lanolin and 3wt% soybean polysaccharide aqueous solution of 2:1:1:25, glycerol, amino silicone oil, lanolin and soybean polysaccharide aqueous solution are weighed respectively for later use;

[0077] S2, adding the weighed 5wt% soybean polysaccharide aqueous solution and glycerol into a three-necked flask, placing the three-necked flask in a 50°C constant temperature water bath, and using an overhead stirrer to stir at a speed of 1500r / min for 30min to obtain a first mixture;

[0078] S3, adding the weighed amino silicone oil to the first mixture, and continuing to stir at a speed of 1500 r / min for 30 min in a 50° C. constant temperature water bath to obtain a second mixture;

[0079] S4. Dissolve the weighed lanolin at 60°C and add it dropwise into the second mixture. Use a digital high-speed disperser homogenizer to shear at 10,000 r / min for 5 minutes. Then transfer it to a three-necked flask and heat it in a 60°C water bath. Use an overhead stirrer to mechanically stir at 1,500 r / min for 180 minutes to obtain 7# aged leather softening agent based on lanolin / soybean polysaccharide.

[0080] When the mass ratio of lanolin to soybean polysaccharide aqueous solution is less than 1:25, it means that the proportion of lanolin is reduced, although the particle size of the prepared lanolin / soy polysaccharide-based aged leather softening agent emulsion is reduced and evenly distributed; however, given that lanolin plays a core softening role in the lanolin / soy polysaccharide-based aged leather softening agent, the mass ratio of lanolin to soybean polysaccharide aqueous solution cannot be less than 1:25.

[0081] Comparative Example 1

[0082] A method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide, which has the same preparation steps as those in Example 1, except that the mass percentage of the soybean polysaccharide aqueous solution in S1 is replaced by 1wt% from 3wt%, and the stirring time in S4 is replaced by 4h from 3h, comprising the following steps:

[0083] S1. According to the mass ratio of glycerol, amino silicone oil, lanolin and 1 wt% soybean polysaccharide aqueous solution of 2:1:1:10, glycerol, amino silicone oil, lanolin and soybean polysaccharide aqueous solution are weighed respectively for later use;

[0084] S2, adding the weighed 5 wt% soybean polysaccharide aqueous solution and glycerol into a three-necked flask, placing the three-necked flask in a 60° C. constant temperature water bath, and using an overhead stirrer to stir at a speed of 1500 r / min for 30 min to obtain a first mixture;

[0085] S3, adding the weighed amino silicone oil to the first mixture, and continuing to stir at a speed of 1500 r / min for 30 min in a constant temperature water bath at 60° C. to obtain a second mixture;

[0086] S4. Dissolve the weighed lanolin at 60°C and add it dropwise into the second mixture. Use a digital high-speed disperser homogenizer to shear at 10,000 r / min for 5 minutes. Then transfer it to a three-necked flask and heat it in a 60°C water bath. Use an overhead stirrer to mechanically stir it at 1,500 r / min for 4 hours. The emulsion stratification is quite serious.

[0087] Comparative Example 2

[0088] A method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide, which has the same preparation steps as those of comparative example 1, except that the mass percentage of the soybean polysaccharide aqueous solution in S1 is replaced by 10wt% from 1wt%, and comprises the following steps:

[0089] S1. According to the mass ratio of glycerol, amino silicone oil, lanolin and 10wt% soybean polysaccharide aqueous solution of 2:1:1:10, glycerol, amino silicone oil, lanolin and soybean polysaccharide aqueous solution are weighed respectively for later use;

[0090] S2, adding the weighed 5 wt% soybean polysaccharide aqueous solution and glycerol into a three-necked flask, placing the three-necked flask in a 60° C. constant temperature water bath, and using an overhead stirrer to stir at a speed of 1500 r / min for 30 min to obtain a first mixture;

[0091] S3, adding the weighed amino silicone oil to the first mixture, and continuing to stir at a speed of 1500 r / min for 30 min in a constant temperature water bath at 60° C. to obtain a second mixture;

[0092] S4. Dissolve the weighed lanolin at 60°C and add it dropwise to the second mixture, use a digital high-speed dispersing homogenizer to shear at 10,000 r / min for 5 minutes, then transfer it to a three-necked flask and heat it in a 60°C water bath, use an overhead stirrer to mechanically stir at 1500 r / min for 180 minutes to obtain 8# lanolin / soy polysaccharide-based aged leather softening agent. The particle size of 8# lanolin / soy polysaccharide-based aged leather softening agent emulsion is too large, and it is difficult to penetrate into the leather.

[0093] Comparative Example 3

[0094] A method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide, which has the same preparation steps as those of comparative example 2, except that the mass ratio of glycerol, amino silicone oil, lanolin and 10wt% soybean polysaccharide aqueous solution in S1 is 2:1:1:20, and comprises the following steps:

[0095] S1. According to the mass ratio of glycerol, amino silicone oil, lanolin and 10wt% soybean polysaccharide aqueous solution of 2:1:1:20, glycerol, amino silicone oil, lanolin and soybean polysaccharide aqueous solution are weighed respectively for later use;

[0096] S2, adding the weighed 5 wt% soybean polysaccharide aqueous solution and glycerol into a three-necked flask, placing the three-necked flask in a 60° C. constant temperature water bath, and using an overhead stirrer to stir at a speed of 1500 r / min for 30 min to obtain a first mixture;

[0097] S3, adding the weighed amino silicone oil to the first mixture, and continuing to stir at a speed of 1500 r / min for 30 min in a constant temperature water bath at 60° C. to obtain a second mixture;

[0098] S4. Dissolve the weighed lanolin at 60°C and add it dropwise to the second mixture, use a digital high-speed dispersing homogenizer to shear at 10,000 r / min for 5 minutes, then transfer it to a three-necked flask and heat it in a 60°C water bath, use an overhead stirrer to mechanically stir at 1500 r / min for 180 minutes to obtain 9# lanolin / soy polysaccharide-based aged leather softening agent. The average particle size of the 9# lanolin / soy polysaccharide-based aged leather softening agent emulsion is too large, and it is difficult to penetrate into the leather.

[0099] Figure 1 This is the particle size distribution diagram of the soybean polysaccharide aqueous solution used in the present invention. Figure 1 It is known that the particle size distribution of soybean polysaccharide aqueous solution is concentrated in two ranges: 0.05μm-0.12μm and 0.31μm-0.89μm. The particle size distribution diagram of soybean polysaccharide aqueous solution shows that the particle size of the soybean polysaccharide aqueous solution used this time is in the range of 0.05μm-0.12μm, and most of them are concentrated in the range of 0.31μm-0.89μm.

[0100] Figure 2 This is the infrared spectrum of soybean polysaccharide used in the present invention. Figure 2 It was found that soybean polysaccharide showed characteristic absorption peaks of polysaccharides, and the -OH stretching vibration peak appeared at 3422cm -1 Nearby. 2928cm -1 The characteristic absorption peak nearby is the CH stretching vibration, but the peak intensity is relatively weak. The uronic acid group appears at 1730cm -1The carbon-oxygen double bond stretching vibration in the free ester group leads to the absorption peak of 1628 cm -1 Absorption peak near 1073cm -1 The peaks nearby are vibration peaks of COC. The infrared spectrum results show that the characteristic functional groups of soybean polysaccharides are aldehyde, ester and hydroxyl groups.

[0101] Depend on Figure 3 It is known from (a)(a1)(b)(b1)(c)(c1) that when the mass percentage of the soybean polysaccharide aqueous solution is 3wt%, the particle size distribution of the aged leather softening agent based on lanolin / soy polysaccharide is in the range of 1.7μm to 32.2μm. As the amount of lanolin decreases, the particle size of the prepared aged leather softening agent based on lanolin / soy polysaccharide decreases, and the uniformity of the particle size distribution increases; when the mass ratio of lanolin to the soybean polysaccharide aqueous solution is 1:10, the particle size distribution is 1.7μm to 32.2μm; when the mass ratio of lanolin to the soybean polysaccharide aqueous solution is 1:20, the particle size distribution is 6μm to 24μm;

[0102] Depend on Figure 3 It is known from (d)(d1)(e)(e1)(f)(f1) that when the mass percentage of the soybean polysaccharide aqueous solution is 5wt%, the particle size distribution range of the aged leather softening agent based on lanolin / soy polysaccharide is 5.0μm to 31.6μm. As the oil phase content decreases, the particle size of the prepared aged leather softening agent based on lanolin / soy polysaccharide changes slightly, and the particle size distribution becomes uniform; when the mass ratio of lanolin to the soybean polysaccharide aqueous solution is 1:10, the particle size distribution is 6.4μm to 31.6μm; when the mass ratio of lanolin to the soybean polysaccharide aqueous solution is 1:20, the particle size distribution is 5μm to 24μm;

[0103] Depend on Figure 3 It can be seen from (g)(g1)(h)(h1) that when the mass percentage of soybean polysaccharide aqueous solution is 10wt%, the particle size distribution range of the aged leather softening agent based on lanolin / soy polysaccharide is 17.3μm~32.2μm; with the increase of soybean polysaccharide content, the particle size of the prepared aged leather softening agent based on lanolin / soy polysaccharide becomes slightly smaller, and the particle size distribution becomes uniform; when the mass ratio of lanolin to soybean polysaccharide aqueous solution is 1:10, the particle size distribution is 20.5μm~32.2μm; when the mass ratio of lanolin to soybean polysaccharide aqueous solution is 1:20, the particle size distribution is 17.3μm~27.8μm.

[0104] Depend on Figure 3 It can be observed from (a2)(b2)(c2)(d2)(e2)(f2)(g2)(h2) that the aged leather softening agent based on lanolin / soybean polysaccharide prepared by the present invention is a uniform and stable emulsion.

[0105] The softening agent obtained in Examples 1 to 6 of the present invention is used as an example to soften aged leather. The specific application method and results are as follows:

[0106] (1) Preparation of aged leather samples

[0107] S1. Weighing: Cut the sheepskin, weigh it and record it. Use a wide range pH test paper to test the pH value of the acid-soaked leather surface and record it (pH = 2-3).

[0108] S2. Salt soaking the sample: Use an electronic balance to weigh 7wt% of the sodium chloride NaCl of the sheepskin, put it into two 1000mL beakers respectively, and add 200wt% deionized water into them, then put the corresponding sheepskin into the solution, and shake it in a constant temperature water bath shaker at 30℃ for 1h. The purpose of salt soaking is to prevent acid swelling.

[0109] S3. Deacidification treatment: pour out the salt solution, weigh 2wt% of the weight of the sheepskin with an electronic balance, oscillate at a constant temperature of 30°C for 30 minutes in a liquid-free state, deacidify until the pH value of the leather surface measured by pH test paper reaches 4-5, and the deacidification time is 30 minutes. Under this condition, the structure of the sheepskin is conducive to the entry of rubber bowl tannin into the leather fiber for tanning.

[0110] S4. Tanning: ① Use an electronic balance to weigh 10wt% of the sheepskin weight of rubber bowl tannin and add it to a beaker, then put the sheepskin into the tanning solution and oscillate for 2 days under the same conditions until the color of the tanning agent becomes lighter; ② Use an electronic balance to weigh 15wt% of the sheepskin weight of rubber bowl tannin and add it to the above beaker, and continue to oscillate for 4 days under the same conditions until the color of the tanning agent becomes lighter; ③ Use an electronic balance to weigh 20wt% of the sheepskin weight of rubber bowl tannin, add it to the above beaker, and oscillate at the same temperature for 9 days until the color of the cross section of the sheepskin is uniform, that is, tanned.

[0111] S5. Rinse: Wash with distilled water for 30 minutes, change the water every 10 minutes, rub the sheepskin in the middle to wash away the excess tannin that is not involved in the tanning. Then place the leather sample in a ventilated and dry place, dry it naturally and set it aside.

[0112] S6. Aging: setting the oven temperature to 120° C., aging the sample for 8 days to obtain an aged rubber-tanned leather sample.

[0113] (2) Softening of aged rubber tanned leather samples

[0114] Use brushing method to soften, the specific method is as follows:

[0115] First, moisten the aged rubber-tanned leather sample with distilled water for 30 minutes to soften it, and then use a brush to apply the softening agent to its surface. After the aged rubber-tanned leather sample completely absorbs the softening agent, apply it again until the quality of the aged rubber-tanned leather sample no longer changes. Each time, leave an interval of 20 minutes, and then place it in a ventilated environment to dry naturally.

[0116] (3) Characterization of properties of aged rubber tanned leather samples before and after softening

[0117] a. Differential Scanning Calorimetry (DSC) Test: This experiment measured DSC using a differential scanning calorimeter model 214Polyma from NETZSCH Instruments GmbH, Germany. The heating rate was set to 10°C / min, the heating range was 25°C to 250°C, the protective gas flow rate P2, i.e., N2, was 40 mL / min, and the furnace protective gas flow rate PG, i.e., N2, was 60 mL / min; wherein, the protective gas was N2.

[0118] b. Thermogravimetric analysis: Thermogravimetric analysis of the present invention adopts a thermogravimetric analyzer model 209F3Tarsus of NETZSCH Instrument Co., Ltd. of Germany, with a heating rate of 10°C / min, a heating range of 40°C to 600°C, a protective gas flow rate P2 of 50mL / min, and a furnace protective gas flow rate PG of 20mL / min; wherein the protective gas is N2.

[0119] c. Color difference test: The aged rubber-tanned leather sample before softening is used as the benchmark to analyze the color difference value and color difference change of the aged rubber-tanned leather sample before and after softening. Use the high-precision colorimeter model JZ-600 of Jinzhun Technology Hong Kong Co., Ltd., and take the unaged rubber-tanned leather sample as the blank sample; before measurement, zero point calibration and white plate calibration should be performed to measure the color difference of the grain layer of the rubber-tanned leather sample. Take three different test points for each sample, and avoid light during the measurement process; record the measured brightness (L*), color difference (a, b), and color difference value ΔE, the calculation method is shown in Formula 1, and then average the obtained data.

[0120]

[0121] In order to further analyze the influence of softening on the color of leather, the present invention adopts a high-precision colorimeter to measure the brightness and chromaticity of the sample before and after softening, and calculates the brightness difference (ΔL), chromaticity difference (Δa, Δb) and overall color difference (ΔE) before and after softening.

[0122] d. Softness test: A leather softness tester model GT-303-D was used to measure the softness of the grain layer of the aged rubber-tanned leather samples. Standard iron sheets and leather sheets were used for calibration before measurement. Three different test points were taken for each aged rubber-tanned leather sample, and the softness data were recorded. The average value of the obtained data was taken as the softness of the aged rubber-tanned leather sample to analyze the change in softness before and after softening.

[0123] One of the most important properties of leather products is softness, which is usually determined by the size of the movement space of collagen fibers and the relative sliding difficulty of them.

[0124] Depend on Figure 4 (a) It is known that as the proportion of oil phase decreases, its softness first decreases and then increases; Figure 4 The results of (b) show that for the aged leather softening agent based on lanolin / soy polysaccharide prepared with 5wt% soybean polysaccharide aqueous solution, as the mass ratio of lanolin to soybean polysaccharide aqueous solution decreases, the softness recovery effect after softening becomes worse. This is because, in the aged leather softening agent based on lanolin / soy polysaccharide, the soybean polysaccharide concentration is relatively high and the oil phase content is too high, resulting in the softening agent being unable to fully penetrate into the leather fiber and being blocked on the surface, causing the leather softness recovery effect to deteriorate. By comparing the softness of aged rubber-tanned leather samples before and after softening, it was found that the softness of the aged rubber-tanned leather samples was greatly improved after using the aged leather softening agent based on lanolin / soy polysaccharide, indicating that the aged leather softening agent based on lanolin / soy polysaccharide can repair the leather crusting phenomenon; compared with 1#, 2# and 3# aged leather softening agents based on lanolin / soy polysaccharide prepared with 3wt% soybean polysaccharide, 4#, 5# and 6# aged leather softening agents based on lanolin / soy polysaccharide prepared with 5wt% soybean polysaccharide have better effect on restoring softness.

[0125] Depend on Figure 5 It was observed that the glossiness of the surface of the aged rubber-tanned leather samples was significantly improved after softening, but the color of the aged rubber-tanned leather samples was deepened to varying degrees after softening.

[0126] Depend on Figure 6 It is known that after softening, ΔL is a positive value, indicating that the color of the leather becomes darker after softening, and the concentration of soybean polysaccharides remains unchanged. The softening agent prepared by changing the ratio of oil phase to water phase has different effects on the color. Reducing the oil phase content, that is, when the mass ratio of lanolin to soybean polysaccharide aqueous solution is 1:20, the color change before and after softening is reduced.

[0127] contrast Figure 6 (a) and Figure 6(b) It was found that the softening agent prepared with 3wt% soybean polysaccharide had less effect on the color of rubber tanned leather than the softening agent prepared with 5wt% soybean polysaccharide. The yellowness change Δb was smaller. The aged leather softening agent based on lanolin / soybean polysaccharide of the present invention was yellowish due to the presence of lanolin, so the yellowness change before and after softening was small. It can be seen from this that the aged leather softening agent based on lanolin / soybean polysaccharide of the present invention is effective in changing the surface color of leather. In terms of color change, the aged leather softening agent based on lanolin / soybean polysaccharide of Example 3 has the best softening effect.

[0128] Depend on Figure 7 It was found that the pyrolysis of aged rubber-tanned leather samples was divided into three stages: first, within 120°C, the volatile small molecular components inside the aged rubber-tanned leather samples began to evaporate; then, the quality of the aged rubber-tanned leather samples decreased rapidly, because the fibers of the aged rubber-tanned leather samples were rapidly decomposed when heated between 250°C and 450°C, and this stage was the main pyrolysis stage; finally, when the temperature exceeded 500°C, the quality decline became slow, and this stage was mainly the further carbonization of the aged rubber-tanned leather samples at high temperature.

[0129] By comparing the TG curves before and after softening, we can see that the stage of rapid weight loss of aged rubber-tanned leather samples after softening is advanced to varying degrees. This is because the volatile oils fill the gaps between the fibers of the aged rubber-tanned leather samples during the softening period, which increases the volatile small molecules in the aged rubber-tanned leather samples after softening. The corresponding temperature of the aged rubber-tanned leather samples when they reach the maximum weight loss rate between the two stages before and after softening does not change significantly, which is about 320℃. Moreover, Figure 7 It can be seen from (d) that the maximum weight loss rate after softening decreases, that is, the peak value of the DTG curve decreases, indicating that the aged rubber-tanned leather sample has restored its thermal stability. This shows that the aged leather softening agent based on lanolin / soybean polysaccharide prepared by the present invention does not have an adverse effect on the thermal stability of the aged rubber-tanned leather sample.

[0130] Depend on Figure 8 It is known that the DSC curve of the aged rubber tanned leather sample has two endothermic peaks at 75℃ and 220℃ respectively; 75℃, that is, the peak T1 is related to the thermal shrinkage temperature of the aged rubber tanned leather sample. The higher the temperature, the better the thermal stability of the aged rubber tanned leather sample. After softening with 3#, 4# and 5# softening agents, the peak moves to high temperature, indicating that the thermal stability of the aged rubber tanned leather sample has improved; T2 temperature corresponds to the decomposition of the structure of collagen. After softening, due to the immersion of the softening agent, it fills between the collagen fibers, increases the spacing between the collagen fibers, destroys the local order of the collagen fibers, and makes the endothermic peak at this position disappear.

[0131] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. An aged leather softening agent based on lanolin / soybean polysaccharide, characterized in that: The softening agent is prepared by mixing glycerin, amino silicone oil, lanolin and soybean polysaccharide aqueous solution, and the mass ratio of glycerin, amino silicone oil, lanolin and soybean polysaccharide aqueous solution is 2:1:1:10-25; The mass percentage of the soybean polysaccharide aqueous solution is 3wt% to 5wt%.

2. A method for preparing the aged leather softening agent based on lanolin / soybean polysaccharide according to claim 1, characterized in that: The following steps are involved: Mixing the soybean polysaccharide aqueous solution and glycerol to obtain a first mixture; Adding amino silicone oil to the first mixture and mixing to obtain a second mixture; The melted lanolin is added into the second mixture and mixed to obtain an aged leather softening agent based on lanolin / soybean polysaccharide.

3. The method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide according to claim 2, characterized in that: When preparing the first mixture, the mixing temperature is 50° C. to 60° C., and the mixing time is 15 min to 30 min.

4. The method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide according to claim 2, characterized in that: When preparing the second mixture, the mixing temperature is 50° C. to 60° C., and the mixing time is 15 min to 30 min.

5. The method for preparing an aged leather softening agent based on lanolin / soybean polysaccharide according to claim 2, characterized in that: When preparing the aged leather softening agent based on lanolin / soybean polysaccharide, the mixing temperature is 50°C to 60°C and the mixing time is 150min to 180min.

6. Use of the aged leather softening agent based on lanolin / soybean polysaccharide according to claim 1 in softening aged leather.

7. The use of the aged leather softening agent based on lanolin / soybean polysaccharide according to claim 6 in the softening of aged leather, characterized in that: Apply the aged leather softening agent based on lanolin / soybean polysaccharide to the aged leather surface and let it dry.

8. The use of the aged leather softening agent based on lanolin / soybean polysaccharide according to claim 6 in the softening of aged leather, characterized in that: Repeatedly apply the aged leather surface with a lanolin / soy polysaccharide-based aged leather softening agent until the quality of the aged leather no longer changes.

9. The use of the aged leather softening agent based on lanolin / soybean polysaccharide according to claim 6 in the softening of aged leather, characterized in that: Before applying the aged leather softener based on lanolin / soy polysaccharides, wet the aged leather with distilled water.

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