Waterproof color-changing leather finishing oil as well as preparation method and application thereof

Abstract

The invention provides waterproof color-changing leather finishing oil as well as a preparation method and application thereof. The finishing oil comprises the following components in parts by weight: 80-85 parts of mineral oil; 5 to 10 parts of sorbitan trioleate; 0.2 to 0.3 part of an oil phase antioxidant; 2.5 to 3 parts of an oil phase thickening agent; 5-10 parts of long-chain alkyl modified silicone oil; the oil phase thickening agent is an organic polymer oil phase thickening agent; the carbon atom number of long-chain alkyl of the long-chain alkyl modified silicone oil is 12-16. The waterproof color-changing leather finishing oil disclosed by the invention is low in price and can achieve a color-changing effect similar to that of animal fat; the organic silicon substance and the oil thickening agent component are added, so that the leather has the characteristics of higher hydrophobicity, water stain resistance and the like, genuine leather can obtain a certain self-cleaning function, and the varieties of domestic leather waterproof color-changing oil products are enriched.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemicals and leather chemicals, in particular to a waterproof color-changing leather finishing oil, a preparation method and application thereof, and belongs to a genuine leather surface treatment agent. Background Art

[0002] Among leather products, color-changing leather is a kind of high-grade leather made by special technology. It has a color-changing effect, which means that the stress part of the leather surface has different shades of color under the action of external force. It is a visual effect caused by the difference in the refractive index of light in the aggregation state of genuine leather fibers. It is very popular among consumers. Usually, oil or wax with color-changing properties is injected into the leather, and the leather surface undergoes stress changes such as stretching, bending, friction, top-throwing or rubbing to make the color of the color-changing leather darken. Waterproof color-changing leather is to add waterproof properties to the color-changing effect. Generally, the genuine leather (such as cowhide) is treated with color-changing treatment and waterproof treatment respectively; in terms of structure, waterproof color-changing leather has a cowhide base layer, a color-changing coating layer, an oil wax layer and a waterproof treatment layer. Its processing procedures are often complicated; there are also some simple processing methods, which can directly apply a layer of color-changing oil or thin wax on the leather surface, so that the leather blank has an antique art effect, which can change color according to stress, but the waterproofness is general, and it is easy to seep oil for a long time.

[0003] As oils with "color-changing effects", the leather processing industry generally chooses animal oils such as neatshoe oil and horse oil. The method of applying color-changing oils and waxes through hot roller coating has been enthusiastically sought after by domestic and foreign leather manufacturers in recent years due to its excellent characteristics such as convenient operation and strong style effects. However, due to the selectivity of raw materials and the maturity of the process, there are not many regions in China that have hot roller oil and wax products for leather finishing, and they are mainly concentrated in Taiwan, China and other regions.

[0004] At present, there are many leather color-changing oil products on the market, which usually use animal fats such as neatshoe oil and horse oil as the main oil and have good effects; but their sources are not wide, the prices are high, and low-priced waterproof color-changing oil products that can give leather a certain degree of waterproofness are relatively scarce. Summary of the invention

[0005] In order to solve the technical difficulties in the above-mentioned prior art, the present invention provides a waterproof color-changing leather finishing oil, a preparation method and application thereof. The waterproof color-changing leather finishing oil proposed in the present invention has a relatively low price, can not only give the leather a good color-changing effect, but also make it have good waterproof properties, which is conducive to application.

[0006] The present invention provides a waterproof color-changing leather finishing oil, comprising the following components in parts by weight:

[0007] 80-85 parts of mineral oil;

[0008] 5-10 parts of sorbitan trioleate;

[0009] 0.2-0.3 parts of oil phase antioxidant;

[0010] 2.5-3 parts of oil phase thickener;

[0011] 5-10 parts of long-chain alkyl modified silicone oil;

[0012] The oil phase thickener is an organic polymer oil phase thickener; the carbon number of the long chain alkyl group of the long chain alkyl modified silicone oil is 12-16.

[0013] In some embodiments of the present invention, the mineral oil is 26# white oil.

[0014] In some embodiments of the present invention, the oil phase antioxidant is a BHA antioxidant.

[0015] In some embodiments of the present invention, the melting point of the oil phase thickener is 90-100°C.

[0016] The method for preparing the waterproof color-changing leather finishing oil as described above comprises the following steps:

[0017] Mineral oil and sorbitan trioleate are mixed according to weight, heated and stirred, and then an oil phase antioxidant, an oil phase thickener and a long-chain alkyl modified silicone oil are added in sequence to obtain a waterproof color-changing leather finishing oil.

[0018] In some embodiments of the present invention, the heating is performed to 90-100° C., and the oil phase antioxidant is added after the temperature is raised to 90-100° C., and the temperature is kept for 20-30 minutes.

[0019] In some embodiments of the present invention, the oil phase thickener is added under stirring conditions, and the stirring speed is ≥1000r / min.

[0020] The application method of the waterproof color-changing leather finishing oil as described above comprises the following steps:

[0021] The waterproof color-changing leather finishing oil is rolled on the surface of the leather blank, dried and left to stand to obtain the waterproof color-changing leather.

[0022] In some embodiments of the present invention, the leather blank is a semi-vegetable tanned leather blank; the temperature of the roller coating is 70-90°C, and the drying is drying at 70-85°C.

[0023] In some embodiments of the present invention, the standing time is more than 12 hours, and then an embossing treatment is included, and the embossing treatment temperature is 80-90°C.

[0024] Compared with the prior art, the waterproof color-changing leather finishing oil of the present invention mainly uses low-priced mineral oil, and is matched with a certain proportion of dehydrated sorbitan trioleate, long-chain alkyl modified silicone oil and oil phase thickener and other auxiliary agents. The waterproof color-changing leather finishing oil of the present invention can achieve a color-changing effect similar to that of animal fats and oils; and by adding silicone substances and oil thickener components, the leather can have stronger hydrophobic and water-resistant stain properties, which can make the genuine leather have a certain "self-cleaning" function, and also enrich the category of domestic leather waterproof color-changing oil products. DETAILED DESCRIPTION

[0025] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the technical scheme of the present invention is now described in detail below in conjunction with specific embodiments. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0026] The present invention provides a waterproof color-changing leather finishing oil, comprising the following components in parts by weight:

[0027] 80-85 parts of mineral oil;

[0028] 5-10 parts of sorbitan trioleate;

[0029] 0.2-0.3 parts of oil phase antioxidant;

[0030] 2.5-3 parts of oil phase thickener;

[0031] 5-10 parts of long-chain alkyl modified silicone oil;

[0032] The oil phase thickener is an organic polymer oil phase thickener; the carbon number of the long chain alkyl group of the long chain alkyl modified silicone oil is 12-16.

[0033] The waterproof color-changing leather finishing oil provided by the invention has a relatively low price, can not only give the leather a good color-changing effect, but also make it have good waterproof properties, and is convenient for application.

[0034] The composition ratio of the waterproof color-changing leather finishing oil described in the embodiment of the present invention is mainly based on common mineral oil, including 80-85 parts by weight of mineral oil, such as 80, 82, 84, and 85 parts. The mineral oil contains a variety of hydrocarbon components, such as normal alkanes, cycloalkanes, and aromatic hydrocarbons, which have good thermal stability and chemical stability, are not easy to volatilize and decompose, and are cheap, and are suitable as the main oil component of hot roller oiling. The mineral oil is preferably 26# white oil, which is a mixture of liquid hydrocarbons, and the main component is a mixture of normal isomeric alkanes of C16-C31; the kinematic viscosity (40°C) is 5.7-46mm2 / S, the acid value is ≤0.05, it is stable to acid, light, and heat, insoluble in ethanol, soluble in ether, benzene, petroleum ether, etc., and can be miscible with most fatty oils.

[0035] The embodiment of the present invention combines a certain proportion of Span-85 (5-10 parts of sorbitan trioleate) with mineral oil, which is conducive to achieving a color change effect equivalent to that of animal and plant oils and fats, and has a good oily feel. At the same time, Span-85 can penetrate into the leather fiber and fill the pores well. The Span-85 is sorbitan trioleate, which contains three long oleic acid carbon chains in its molecular chain, has a large molecular volume, and is a lipophilic surfactant. Since it is a surfactant with a low HLB value, it has a hydrophilic group and a lipophilic group with a large molecular weight. After encountering water, Span-85 in the gaps between leather fibers will encapsulate water to form oil-in-water micelles, and will swell and block the fiber pores to prevent subsequent water penetration; after drying and evaporating the moisture of the leather blank, its waterproof properties can be restored. Moreover, Span-85 is a non-toxic, harmless, and environmentally friendly ingredient, so Span-85 can be used as a good dynamic leather body waterproofing agent in the formula of the present invention. Span-85 is also called Span or Span 85. Its HLB value is generally 1.8. Its weight can be 6-9 parts or 7-8 parts. The hydrophile-lipophile balance (HLB value) is a value used to indicate the hydrophilicity or lipophilicity of a surfactant. The smaller the HLB value, the stronger its lipophilicity.

[0036] In addition, the waterproof color-changing leather finishing oil includes 5-10 parts by weight of long-chain alkyl modified silicone oil, preferably 6-8 parts, wherein the number of carbon atoms of the long-chain alkyl group is 12 to 16; the addition of this long-chain alkyl modified silicone oil in the embodiment of the present invention can significantly enhance the waterproofness. The long-chain alkyl modified silicone oil belongs to the silicone-type substance, preferably the silicone waterproofing auxiliary agent produced by Sichuan Dawei Technology Co., Ltd., which is a long-chain alkyl modified (dodecyl modified) silicone oil, that is, a product in which part of the methyl groups in the methyl silicone oil are replaced by long-chain alkyl (dodecyl), and its waterproofness increases with the increase of the number of carbon atoms. Specifically, the effective content of the product is ≥98wt%, and it has good surface waterproof performance.

[0037] The commonly used waterproofing agents in the prior art are silicone waterproofing agents, which can only perform simple surface waterproofing, have unstable waterproofing properties and are easy to affect the natural feel of the leather blank (silicone substances have a strong sense of slipperiness). The Span-85 described in the embodiments of the present invention is a non-toxic, harmless, environmentally friendly ingredient. In combination with other components, it can not only achieve a color change effect and oily feel similar to animal fats at a relatively low cost, but also achieve the purpose of dynamic bulk waterproofing without affecting the air permeability of the leather blank. The long-chain alkyl-modified silicone oil produced by Sichuan Dawi Technology Co., Ltd. used in some embodiments of the present invention has excellent surface waterproofing properties. The preferred embodiment of the present invention combines two waterproof systems, and the resulting waterproof color-changing leather finishing oil (which can be called waterproof roller-coated color-changing oil) has the characteristics of excellent waterproofing properties, strong color change, sufficient oil feel and high cost performance after roller coating.

[0038] Since the long-chain alkyl modified silicone oil has unsatisfactory compatibility with mineral oil and the stability after compounding is insufficient, an oil phase thickener needs to be added; that is, the leather finishing oil includes 2.5-3 parts by weight of an oil phase thickener. The addition of an oil phase thickener in the embodiment of the present invention is beneficial to improving the stability of the oil. If the amount added is too little, the purpose of stabilizing the system cannot be achieved; adding too much will cause the oil viscosity to be too thick, which can easily cause the oil to stay on the leather blank and be unable to penetrate, affecting the application performance. Therefore, after innovative multiple screening in the embodiment of the present invention, an organic polymer oil phase thickener was finally screened out, and the addition amount can be 2.5%-3%. At this time, the penetration and drying performance are better, and the oil phase system can also be stabilized.

[0039] In some embodiments of the present invention, the oil phase thickener is a commercially available product, for example, an organic polymer thickening powder (Shanghai Wanzhao Fine Chemical Co., Ltd.), which can thicken most oil systems and has long-term stability after thickening. The system has excellent high temperature resistance, acid and alkali resistance, and weather resistance, and its melting point is 90-100°C.

[0040] In addition, the embodiment of the present invention assists in using a common oil-phase antioxidant, and its weight ratio is 0.2 to 0.3 parts. The oil-phase antioxidant is preferably a BHA antioxidant, butylated hydroxyanisole (BHA), that is, antioxidant BHA, a white or slightly yellow crystal, a melting point of 48 to 63°C, and is relatively stable to heat. The embodiment of the present invention can also use other oil-phase antioxidants (oil-soluble antioxidants), such as butylated hydroxytoluene (BHT), etc.

[0041] The embodiment of the present invention provides a method for preparing the waterproof color-changing leather finishing oil as described above, comprising the following steps:

[0042] Mineral oil and sorbitan trioleate are mixed according to weight, heated and stirred, and then an oil phase antioxidant, an oil phase thickener and a long-chain alkyl modified silicone oil are added in sequence to obtain a waterproof color-changing leather finishing oil.

[0043] Specifically, the processing steps of the preparation method are as follows:

[0044] 1. Accurately weigh various raw materials and set aside; clean the reactor, add mineral oil and Span-85 into the reactor respectively, start stirring, heat to 90-100°C, stir at full speed, and obtain a uniform first mixture;

[0045] 2. After the temperature rises to 90-100°C, add the oil phase antioxidant to the first mixture, keep warm for 20-30 minutes, and stir at full speed to obtain a uniformly dissolved second mixture;

[0046] 3. After the oil phase antioxidant is completely dissolved, add the oil phase thickener into the reactor and stir at full speed (speed ≥ 1000r / min) to make it completely dissolved evenly;

[0047] 4. After the oil phase thickener is completely dissolved, add the long-chain alkyl modified silicone oil, keep warm and disperse at high speed for 20-30 minutes, then cool down to ≤45°C under high-speed stirring, measure the viscosity, and after the sampling test is qualified, the formed waterproof color-changing leather finishing oil is discharged (viscosity 1000-1500mpa·s (3# rotor, 6r)).

[0048] The embodiment of the present invention also provides an application method of the waterproof color-changing leather finishing oil as described above, comprising the following steps: rolling the waterproof color-changing leather finishing oil on the surface of the leather blank, drying and standing to obtain the waterproof color-changing leather.

[0049] The embodiment of the present invention uses the leather finishing oil described above, and its construction process is as follows:

[0050] (1) Preparation of leather blanks: Since roller oiling requires a construction environment of 70-90℃ and the shrinkage temperature of the leather blank is required to be ≥95℃, brown semi-vegetable tanned cowhide leather blanks are used; the color of the leather blanks is not particularly limited. Vegetable tanned leather blanks are leather blanks formed by processing leather with vegetable tanning agents, and semi-vegetable tanned leather blanks include combined tanning processing methods.

[0051] (2) Construction method:

[0052] The roller coating temperature of the hot roller coater can be set to 70-90°C, preferably 80°C, the leather finishing oil is heated to above 70°C, and poured evenly into the hot roller coater;

[0053] The cut brown semi-vegetable tanned cowhide leather is passed through a roller, so that the leather finishing oil is evenly rolled on the surface of the leather, and the rolling amount is preferably 10g / sf;

[0054] The roller-coated leather blank is dried at 70-85°C, preferably at 80°C for 1-2 minutes, and then left to stand overnight;

[0055] After that, embossing treatment can be carried out, and the processing technology includes: pressing the sand plate of the press machine at 80-90℃, pressure 50kg, 2 seconds and pressure 160kg, 1 second; by embossing under these two preferred conditions, waterproof color-changing leather with strong color change, good uniformity and excellent waterproof performance can be obtained.

[0056] The waterproof color-changing leather obtained in the embodiment of the present invention is evaluated and tested; in the waterproof performance evaluation, water drops can be dropped on the leather blank treated with the waterproof color-changing leather finishing oil to test the surface waterproofness and the bulk waterproofness respectively. In addition, the color-changing effect can be evaluated by visual inspection and other methods. After testing, the waterproof roller-coated color-changing oil obtained in the embodiment of the present invention has excellent waterproof performance, and has the characteristics of strong color change, sufficient oil feeling and high cost performance.

[0057] In order to further understand the present invention, the present invention is described in detail below in conjunction with the examples, and the protection scope of the present invention is not limited by the following examples. In the examples, all original reagents and materials are commercially available, and the experimental methods without specifying the specific experimental conditions are conventional methods and conditions well known in the field. The mineral oil-flavored 26# white oil used; the long-chain alkyl-modified silicone oil is an organosilicon waterproofing aid (dodecyl-modified silicone oil) produced by Sichuan Dawei Technology Co., Ltd., with an effective content of ≥98%. The oil phase thickener is an organic polymer-type thickening powder purchased from Shanghai Wanzhao Fine Chemical Co., Ltd., with a melting point of 90-100°C.

[0058] Example 1

[0059] Preparation of waterproof discoloration leather finishing oil:

[0060] 1. Accurately weigh various raw materials and set aside; clean the reactor, add 80 parts of mineral oil and 10 parts of Span-85 into the reactor, start stirring, heat to 95°C, stir at full speed, and obtain a uniformly mixed first mixture;

[0061] 2. After the temperature rises to 95°C, add 0.3 parts of oil-phase antioxidant BHA to the first mixture, keep warm for 25 minutes, and stir at full speed to obtain a uniformly dissolved second mixture;

[0062] 3. After the oil phase antioxidant BHA is completely dissolved, add 2.7 parts of oil phase thickener to the reactor and stir at full speed at 1000r / min to make it completely dissolved evenly;

[0063] 4. After the oil phase thickener is completely dissolved, add 7 parts of long-chain alkyl modified silicone oil, keep warm and disperse at high speed for 25 minutes, then cool down to ≤45°C under high-speed stirring, measure the viscosity, and after the sampling test is qualified, the formed waterproof color-changing leather finishing oil is discharged.

[0064] Apply the waterproof discoloration leather finish as described:

[0065] The hot roller coater is set to a roller coating temperature of 80°C, the leather finishing oil is heated to above 70°C, and poured evenly into the hot roller coater;

[0066] The cut brown semi-vegetable tanned cowhide leather blank (waterproof light brown shaved leather blank (waterproofness needs to be tested) is polished with 240# once and 320# once, the same as in the following embodiments) through a roller, so that the leather finishing oil is evenly rolled on the surface of the leather blank, and the roller coating amount is 10g / sf;

[0067] Bake the roller-coated leather blank at 80℃ for 1-2 minutes, and then let it stand overnight;

[0068] Afterwards, the sand plate was pressed on a plate pressing machine at 80-90°C, a pressure of 50kg for 2 seconds and a pressure of 160kg for 1 second; by embossing under these two conditions, a waterproof color-changing leather sample was obtained.

[0069] The sample was heat stored at 50°C for 15 days without delamination and had good penetration and drying properties. The leather blank after roll coating of the sample was baked at 80°C for 1-2 minutes and no undried oil sample was present on the leather blank surface.

[0070] The obtained sample leather blanks were evaluated for water resistance and discoloration effect, and the results are as follows: Among them, the sample leather blanks of the control group added with long-chain alkyl modified silicone oil, the specific formula is: 90 parts of 26# white oil + 7 parts of long-chain alkyl modified silicone oil + 2.7 parts of oil phase thickener + 0.3 parts of BHA.

[0071] Table 1 Waterproofness comparison

[0072]

[0073] Note: (1) The wetting level is divided into 1-5 levels, 1 is non-wetting, and 5 is full wetting.

[0074] (2) To verify the leather blanks, select leather blanks from adjacent parts of the same piece of leather, and the surface characteristics and thickness of the leather blanks are almost the same.

[0075] (3) Waterproof test method: drop a certain amount of water on the surface of the leather embryo, put it in a sealed constant temperature and humidity container, start timing, observe the water drop penetration on the surface of the leather embryo after 30 minutes, and get the surface waterproof rating; observe the water seepage on the cross section of the leather embryo after 60 minutes, and get the body waterproof rating. Each group of experiments selects different parts of the leather embryo for testing, and the average value is taken after three measurements.

[0076] Conclusion: It shows that the addition of Span-85 can significantly improve the waterproof performance of the leather blank, not only improving the waterproof performance of the leather blank body, but also improving the waterproof performance of the leather blank surface to a certain extent.

[0077] In addition, the color change effect of the finishing oil of Example 1 was compared with other finishing oils, and the results were as follows: The comparison group included: 26# white oil + Span-80, neat's foot oil, and soybean oil.

[0078] Table 2 Comparison of color change effects

[0079]

[0080] Note: To verify the leather, select leather from adjacent parts of the same piece of leather, with almost the same surface characteristics and thickness. In addition, the discoloration level is generally evaluated by visual inspection.

[0081] Conclusion: It shows that the addition of Span-85 can significantly improve the color change effect and enhance the oil feeling, and can reach or even exceed the application performance of neat's foot oil, but its unit price is much cheaper than that of neat's foot oil.

[0082] Example 2

[0083] Preparation of waterproof discoloration leather finishing oil:

[0084] 1. Accurately weigh various raw materials and set aside; clean the reactor, add 85 parts of mineral oil and 5 parts of Span-85 into the reactor, start stirring, heat to 95°C, stir at full speed, and obtain a uniformly mixed first mixture;

[0085] 2. After the temperature rises to 90°C, add 0.2 parts of oil-phase antioxidant BHA to the first mixture, keep warm for 30 minutes, and stir at full speed to obtain a uniformly dissolved second mixture;

[0086] 3. After the oil phase antioxidant BHA is completely dissolved, add 2.8 parts of oil phase thickener to the reactor and stir at full speed at 1000r / min to make it completely dissolved evenly;

[0087] 4. After the oil phase thickener is completely dissolved, add 7 parts of long-chain alkyl modified silicone oil, keep warm and disperse at high speed for 30 minutes, then cool down to ≤45°C under high-speed stirring, measure the viscosity, and after the sampling test is qualified, the formed waterproof color-changing leather finishing oil is discharged.

[0088] The viscosity of the waterproof color-changing leather finishing oils described in Examples 1-2 is 1000-1500 mPa·s (3# rotor, 6r); the application performance of Example 2 is as follows.

[0089] Table 3 Effect of Span-85 dosage on waterproof performance

[0090]

[0091]

[0092] In addition, the performance of the embossed leather blank (coating oil formula: 90 parts 26# white oil + 7 parts long-chain alkyl modified silicone oil + 2.7 parts oil phase thickener + 0.3 parts BHA) was compared with the reference sample leather blank. The results are as follows:

[0093] Table 4 Comparison of waterproof performance

[0094]

[0095] Note: (1) The wetting level is divided into 1-5 levels, 1 is non-wetting, and 5 is full wetting.

[0096] (2) To verify the leather blanks, select leather blanks from adjacent parts of the same piece of leather, and the surface characteristics and thickness of the leather blanks are almost the same.

[0097] (3) Reference sample leather blank waterproof light brown shaved leather blank (to be tested for water resistance) buffed 240# once and 320# once.

[0098] Conclusion: Compared with the reference sample, the experimental results show that long-chain alkyl-modified silicone oil has stronger surface water-repellent properties.

[0099] As can be seen from the above embodiments, the waterproof color-changing leather finishing oil of the present invention mainly uses mineral oil, and is matched with a certain proportion of anhydrous sorbitan trioleate, long-chain alkyl modified silicone oil and oil phase thickener and other auxiliary agents. The waterproof color-changing leather finishing oil of the present invention is low in price and can achieve a color-changing effect similar to that of animal fats and oils; and by adding silicone substances and oil thickener components, the leather can have stronger hydrophobic and water-resistant stains and other properties, which can make the genuine leather obtain a certain "self-cleaning" function, and also enrich the category of domestic leather waterproof color-changing oil products.

[0100] The above examples are only used to illustrate the technical features and implementation process of the present invention, rather than to limit the technical solution of the present invention. It should be pointed out that for ordinary technicians in this field, the present invention can still be modified or replaced by equivalents, and modifications or replacements that do not deviate from the principles of the present invention are all covered by the protection of the present invention.

Claims

1. A waterproof color-changing leather finishing oil, characterized in that: The composition comprises the following components in parts by weight: 80-85 parts of mineral oil; 5-10 parts of sorbitan trioleate; 0.2-0.3 parts of oil phase antioxidant; 2.5-3 parts of oil phase thickener; 5-10 parts of long-chain alkyl modified silicone oil; The oil phase thickener is an organic polymer oil phase thickener; the carbon number of the long chain alkyl group of the long chain alkyl modified silicone oil is 12-16.

2. The waterproof color-changing leather finishing oil according to claim 1, characterized in that: The mineral oil is 26# white oil.

3. The waterproof color-changing leather finishing oil according to claim 1, characterized in that: The oil phase antioxidant is a BHA antioxidant.

4. The waterproof color-changing leather finishing oil according to any one of claims 1 to 3, characterized in that: The melting point of the oil phase thickener is 90-100°C.

5. A method for preparing the waterproof color-changing leather finishing oil according to any one of claims 1 to 4, comprising the following steps: According to weight parts, mineral oil and sorbitan trioleate are mixed, heated and stirred, and then an oil phase antioxidant, an oil phase thickener and a long-chain alkyl modified silicone oil are added in sequence to obtain a waterproof color-changing leather finishing oil.

6. The preparation method according to claim 5, characterized in that: The heating is to 90-100° C., and the oil phase antioxidant is added when the temperature is raised to 90-100° C., and the temperature is kept for 20-30 minutes.

7. The preparation method according to claim 6, characterized in that: The oil phase thickener is added under stirring conditions, and the stirring speed is ≥1000r / min.

8. The method for applying the waterproof color-changing leather finishing oil according to any one of claims 1 to 4, comprising the following steps: The waterproof color-changing leather finishing oil is rolled on the surface of the leather blank, dried and left to stand to obtain the waterproof color-changing leather.

9. The application method according to claim 8, characterized in that: The leather blank is a semi-vegetable tanned leather blank; the temperature of the roller coating is 70-90°C, and the drying is performed at 70-85°C.

10. The application method according to claim 9, characterized in that: The standing time is more than 12 hours, and then an embossing treatment is included, and the temperature of the embossing treatment is 80-90°C.

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