High-physical-property sofa leather brightener as well as preparation method and coating process thereof

Abstract

The invention relates to the technical field of functional brighteners, in particular to a high-physical-property sofa leather brightener as well as a preparation method and a coating process thereof. The high-physical-property sofa leather brightener is prepared from the following raw materials in parts by mass: 30 to 40 parts of nitrocotton gloss oil, 30 to 40 parts of beewax, 10 to 15 parts of polyethylene wax and 10 to 15 parts of patching paste. The high-physical-property sofa leather brightener disclosed by the invention has excellent wear resistance, softness, high-temperature stability and yellowing resistance.

Description

Technical Field

[0001] The present application relates to the technical field of functional brighteners, and more specifically, to a sofa leather brightener with high physical properties and a preparation method and coating process thereof. Background Art

[0002] With the development of the leather industry, leather products are increasingly used in people's daily lives. In the leather making process, leather finishing is an extremely important process, which has a vital impact on the appearance, hygiene and physical-mechanical properties of leather products. Its performance even affects the impression of the product in the minds of consumers. The use of leather brighteners with excellent performance is one of the important processes to ensure the quality of finished leather.

[0003] Leather brightener is a leather additive used for leather care, which is mainly used to improve the appearance and texture of leather and reduce the damage to leather caused by external factors. The main ingredients of leather brightener include waxes and oils. The role of waxes is to form a protective film on the surface of leather, thereby increasing the gloss and water resistance of leather; while the role of oils is to moisturize leather and reduce the possibility of leather aging and cracking.

[0004] However, when brightener is used on materials that frequently come into contact with the human body, such as sofa leather, the surface of the sofa leather is easily rubbed or scratched during daily use, thus placing higher requirements on the wear-resistant protection performance of the brightener. Summary of the invention

[0005] In order to improve the defect that conventional leather brighteners have insufficient wear-resistant protection performance for leather, the present application provides a sofa leather brightener with high physical properties and a preparation method and coating process thereof.

[0006] In the first aspect, the present application provides a sofa leather brightener with high physical properties, which adopts the following technical solution: A sofa leather brightener with high physical properties comprises the following raw materials in parts by weight: 30-40 parts of nitrocellulose varnish, 30-40 parts of beeswax, 10-15 parts of polyethylene wax and 10-15 parts of wound repairing ointment.

[0007] The high-property sofa leather brightener of the present application uses varnish, natural wax, synthetic wax and repairing ointment as raw materials, wherein the varnish is nitrocellulose varnish, the synthetic wax is ethylene wax, and the natural wax is beeswax or paraffin. Compared with paraffin, the use of beeswax will enable the high-property sofa leather brightener to have better wear resistance and softness.

[0008] The reason may be that beeswax contains ester components, which enable the beeswax molecules to form a tighter and more orderly arrangement, and the intermolecular force is stronger. In addition, beeswax has a higher hardness and a certain rigidity, which enables the high physical property sofa leather brightener to better resist external forces when rubbed and is not easily worn.

[0009] The molecular structure of paraffin is relatively simple, and the intermolecular force is relatively weak, which makes it easier for the molecules of the high-physical property sofa leather brightener to slide or shift when rubbed, making it more susceptible to wear, and even scratches and peeling.

[0010] In summary, when beeswax is used as natural wax, the high physical property sofa leather brightener will make the sofa leather have better wear resistance.

[0011] In addition, the high-property sofa leather brightener of the present application has excellent thermal stability, and the emulsion does not delaminate for 50 days at room temperature and does not delaminate for 50 days at a heat storage temperature of 50°C. At the same time, the high-property sofa leather brightener has excellent high temperature resistance, and the yellowing resistance level still reaches level 4-5 after being treated at a temperature of 129°C for 12 hours.

[0012] Preferably, the wound repairing ointment comprises the following raw materials in parts by weight: 50-60 parts of antioxidant polyurethane emulsion, 2-4 parts of filling material, 1-3 parts of thickener, 1-3 parts of defoaming agent and 20-50 parts of deionized water, wherein the antioxidant polyurethane emulsion contains 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and didodecyl thiodipropionate.

[0013] The molecular structure of nitrocellulose varnish contains unstable nitrate groups. During storage and use, especially in a high temperature and high humidity oxygen environment, nitrocellulose varnish is prone to oxidation reaction. The oxidation reaction will cause the molecular structure of nitrocellulose varnish to change and produce a small amount of chromophore groups, thereby causing the sofa leather brightener to turn yellow. As the temperature increases and the storage time increases, the yellowing of the sofa leather brightener will become more obvious.

[0014] In order to improve the defect that sofa leather brightener is prone to yellowing after long-term storage, the applicant combines 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and didodecyl thiodipropionate to form a composite antioxidant, and through the synergistic effect, further reduce the possibility of yellowing of sofa leather brightener.

[0015] The mechanism is that 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate is a bisphenol monoacrylate antioxidant, 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine is a hindered phenol antioxidant, and didodecyl thiodipropionate is a thioether antioxidant.

[0016] When nitrocellulose varnish is subjected to high temperature aging, some unstable bonds (such as ester bonds) in the nitrocellulose molecules break, and the alkyl parts connected to these bonds may be separated in the form of free radicals to form alkyl free radicals. The alkyl free radicals are further oxidized to form peroxy free radicals, which then capture hydrogen atoms in the nitrocellulose varnish to form new alkyl free radicals and hydroperoxides, thereby further accelerating the yellowing of the nitrocellulose varnish.

[0017] 2-(2-Hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate can capture alkyl radicals and inhibit the aging of nitrocellulose varnish from the root elements, while 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine can capture peroxy radicals and didodecyl thiodipropionate can capture hydroperoxides. Therefore, when the three are used in combination, antioxidant treatment will be carried out at three different stages of aging of nitrocellulose varnish, thereby further reducing the possibility of yellowing of sofa leather brightener.

[0018] Preferably, the mass ratio of 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and didodecyl thiodipropionate is (1-3):(2-4):(1-3).

[0019] Preferably, the antioxidant polyurethane further contains nonylphenol polyoxyethylene ether.

[0020] Beeswax is a non-polar or weakly polar substance, while nitrocellulose varnish is a polar substance. The polarity difference between the two is large, and the intermolecular force is small, so it is difficult for them to dissolve in each other or mix evenly. As a result, after the leather brightener is left for a long time, stratification is likely to occur. In a hot storage environment, the molecular movement of beeswax and nitrocellulose varnish will be more active, further causing stratification.

[0021] Nonylphenol polyoxyethylene ether has both hydrophilic groups and lipophilic groups. This structure can significantly reduce the surface tension of the liquid. When nonylphenol polyoxyethylene ether is added to antioxidant polyurethane, and antioxidant polyurethane is added to sofa leather brightener, nonylphenol polyoxyethylene ether will be oriented, with the hydrophilic group facing the water phase and the lipophilic group facing the oil phase, thereby reducing the tension of the oil-water interface, allowing beeswax and nitrocellulose varnish to be evenly dispersed in water to form a stable emulsion, thereby effectively reducing the possibility of stratification of the sofa leather brightener after long-term storage.

[0022] Preferably, the antioxidant polyurethane emulsion comprises the following raw materials in parts by mass: 30-40 parts of aqueous polyurethane emulsion, 10-16 parts of nonylphenol polyoxyethylene ether, 1-3 parts of 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 2-4 parts of 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and 1-3 parts of didodecyl thiodipropionate.

[0023] Preferably, the filling material is one or a mixture of polymer hollow microspheres, kaolin, silicon dioxide, titanium dioxide and light calcium carbonate; and / or; The thickener is one of RM-8W, PU1341 and RHEOLATE 299; and / or; The defoamer is one of YL-801, EFKA SI 2741 and DU-1242.

[0024] In the second aspect, the present application provides a method for preparing a sofa leather brightener with high physical properties, using the following technical solution: A method for preparing a sofa leather brightener with high physical properties comprises the following steps: Step 1: First, mix nitrocellulose varnish and beeswax to obtain a first mixed solution; Step 2: mixing the first mixed solution with polyethylene wax to obtain a second mixed solution; Step 3: Mix the second mixed liquid with the repairing ointment to obtain a sofa leather brightener with high physical properties.

[0025] In the third aspect, the present application provides a coating process for a sofa leather brightener with high physical properties, which adopts the following technical solution: A coating process for a high-property sofa leather brightener comprises the following steps: S1. Spray the high-property sofa leather brightener evenly on the surface of the sofa leather, and control the spraying thickness to 1-3g per square foot; S2. Transfer the sofa leather into an oven and heat at 90-110°C for 2-4h; S3. Place the sofa leather at room temperature for 6-8 hours to form a stable coating layer; S4. Perform tumbling treatment on the sofa leather at 100-120°C to obtain hot spots with high physical properties.

[0026] Bright spots can cause leather to produce a unique gloss and three-dimensional sense, breaking the monotony of the traditional leather surface, making it more fashionable and attractive. At present, the formation of bright spots usually adopts the tumbling bright spot process, while the present application innovatively uses 100-120℃ hot spot treatment. Compared with the tumbling bright spot process, the hot spot process is shorter. The process time of tumbling bright spots is nearly 8 hours, while the process time of hot spot is only 1 hour, which significantly improves the operation time of the bright spot process and improves the efficiency of sofa leather preparation. Moreover, compared with the tumbling bright spot process, the hot spot process can cause the sofa leather to have better wear resistance and softness.

[0027] In summary, this application has the following beneficial effects: 1. The high-property sofa leather brightener of the present application is made of varnish, natural wax, synthetic wax and repairing ointment as raw materials, wherein the varnish is nitrocellulose varnish, the synthetic wax is ethylene wax, and the natural wax is beeswax or paraffin. Compared with paraffin, the use of beeswax will enable the high-property sofa leather brightener to have better wear resistance and softness.

[0028] 2. In order to improve the defect that sofa leather brightener is prone to yellowing after long-term storage, the applicant combines 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and didodecyl thiodipropionate to form a composite antioxidant, and through the synergistic effect, further reduce the possibility of yellowing of sofa leather brightener.

[0029] 3. Bright spots can make the leather produce unique gloss and three-dimensional sense, break the monotony of traditional leather surface, and make it more fashionable and attractive. At present, the formation of bright spots usually adopts the tumbling bright spot process, while the present application innovatively uses 100-120℃ hot bright spot treatment. Compared with the tumbling bright spot process, the hot bright spot process takes less time. The process time of tumbling bright spots is nearly 8 hours, while the process time of hot bright spots is 1 hour. The operation time of the bright spot process is significantly improved, and the efficiency of sofa leather preparation is improved. Moreover, compared with the tumbling bright spot process, the hot bright spot process can make the sofa leather have better wear resistance and softness. DETAILED DESCRIPTION

[0030] The present application is further described in detail below in conjunction with Examples 1 to 8 and Comparative Example 1.

[0031] raw material Nitrocellulose varnish silver resin 765816; beeswax, paraffin and silicon dioxide are commercially available; polyethylene wax CAS: 9002-88-4; sofa leather Guangdong Wanbian PVC artificial leather; water-based polyurethane emulsion PU667; 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate antioxidant ao-3052; 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine triphenol antioxidant 3224; didodecyl thiodipropionate CAS: 123-28-4; nonylphenol polyoxyethylene ether NP-10; thickener PU1341; defoamer YL-801.

[0032] Example 1 A sofa leather brightener with high physical properties comprises the following raw materials: 35g of nitrocellulose varnish, 35g of beeswax, 12g of polyethylene wax and 13g of wound repairing ointment.

[0033] The wound-repairing ointment is prepared by mixing the following raw materials: 55 g of antioxidant polyurethane emulsion, 3 g of filler material - silicon dioxide, 2 g of thickener PU1341, 2 g of defoamer YL-801 and 40 g of deionized water.

[0034] Antioxidant polyurethane emulsion is obtained by mixing the following raw materials: 35g water-based polyurethane emulsion, 13g nonylphenol polyoxyethylene ether and 2g 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate.

[0035] A method for preparing a sofa leather brightener with high physical properties comprises the following steps: Step 1: First, mix nitrocellulose varnish and beeswax to obtain a first mixed solution; Step 2: mixing the first mixed solution with polyethylene wax to obtain a second mixed solution; Step 3: Mix the second mixed liquid with the repairing ointment to obtain a sofa leather brightener with high physical properties.

[0036] A coating process for a high-property sofa leather brightener comprises the following steps: S1. Spray the high-property sofa leather brightener evenly on the surface of the sofa leather, and control the spraying thickness to 2g per square foot; S2, transfer the sofa leather into an oven and heat at 100°C for 3h; S3, placing the sofa leather at room temperature for 7 hours to form a stable coating layer; S4. The sofa leather is thrashed and polished to obtain high-property thrashing highlights, and the thrashing time is 8 hours.

[0037] Example 2 A sofa leather brightener with high physical properties comprises the following raw materials: 35g of nitrocellulose varnish, 35g of beeswax, 12g of polyethylene wax and 13g of wound repairing ointment.

[0038] The wound-repairing ointment is prepared by mixing the following raw materials: 55 g of antioxidant polyurethane emulsion, 3 g of filler material - silicon dioxide, 2 g of thickener PU1341, 2 g of defoamer YL-801 and 40 g of deionized water.

[0039] Antioxidant polyurethane emulsion is obtained by mixing the following raw materials: 35g water-based polyurethane emulsion, 13g nonylphenol polyoxyethylene ether and 2g 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate.

[0040] A method for preparing a sofa leather brightener with high physical properties comprises the following steps: Step 1: First, mix nitrocellulose varnish and beeswax to obtain a first mixed solution; Step 2: mixing the first mixed solution with polyethylene wax to obtain a second mixed solution; Step 3: Mix the second mixed liquid with the repairing ointment to obtain a sofa leather brightener with high physical properties.

[0041] A coating process for a high-property sofa leather brightener comprises the following steps: S1. Spray the high-property sofa leather brightener evenly on the surface of the sofa leather, and control the spraying thickness to 2g per square foot; S2, transfer the sofa leather into an oven and heat at 100°C for 3h; S3, placing the sofa leather at room temperature for 7 hours to form a stable coating layer; S4. The sofa leather is subjected to tumbling treatment at 110°C to obtain hot spots with high physical properties. The tumbling time is 1 hour.

[0042] Example 3 The difference from Example 2 is that the antioxidant polyurethane emulsion is mixed by the following raw materials: 35g of aqueous polyurethane emulsion, 13g of nonylphenol polyoxyethylene ether and 3g of 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine.

[0043] Example 4 The difference from Example 2 is that the antioxidant polyurethane emulsion is obtained by mixing the following raw materials: 35 g of aqueous polyurethane emulsion, 13 g of nonylphenol polyoxyethylene ether and 2 g of didodecyl thiodipropionate.

[0044] Example 5 The difference from Example 2 is that the antioxidant polyurethane emulsion is mixed by the following raw materials: 35g of aqueous polyurethane emulsion, 13g of nonylphenol polyoxyethylene ether, 2g of 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 3g of 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and 2g of didodecyl thiodipropionate.

[0045] Example 6 The difference from Example 5 is that the antioxidant polyurethane emulsion is mixed by the following masses of raw materials: 35 g of aqueous polyurethane emulsion, 13 g of nonylphenol polyoxyethylene ether, 1 g of 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 4 g of 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and 1 g of didodecyl thiodipropionate.

[0046] Example 7 The difference from Example 5 is that the antioxidant polyurethane emulsion is mixed by the following raw materials: 35g of aqueous polyurethane emulsion, 13g of nonylphenol polyoxyethylene ether, 3g of 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 2g of 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and 3g of didodecyl thiodipropionate.

[0047] Example 8 The difference from Example 5 is that no nonylphenol polyoxyethylene ether is added to the antioxidant polyurethane emulsion.

[0048] Comparative Example Comparative Example 1 A sofa leather brightener with high physical properties comprises the following raw materials: 35g of nitrocellulose varnish, 35g of paraffin wax, 12g of polyethylene wax and 13g of wound repairing ointment.

[0049] The wound-repairing ointment is prepared by mixing the following raw materials: 55 g of antioxidant polyurethane emulsion, 3 g of filler material - silicon dioxide, 2 g of thickener PU1341, 2 g of defoamer YL-801 and 40 g of deionized water.

[0050] Antioxidant polyurethane emulsion is obtained by mixing the following raw materials: 35g water-based polyurethane emulsion, 13g nonylphenol polyoxyethylene ether and 2g 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate.

[0051] A method for preparing a sofa leather brightener with high physical properties comprises the following steps: Step 1: First, mix nitrocellulose varnish and paraffin to obtain a first mixed solution; Step 2: mixing the first mixed solution with polyethylene wax to obtain a second mixed solution; Step 3: Mix the second mixed liquid with the repairing ointment to obtain a sofa leather brightener with high physical properties.

[0052] A coating process for a high-property sofa leather brightener comprises the following steps: S1. Spray the high-property sofa leather brightener evenly on the surface of the sofa leather, and control the spraying thickness to 2g per square foot; S2, transfer the sofa leather into an oven and heat at 100°C for 3h; S3, placing the sofa leather at room temperature for 7 hours to form a stable coating layer; S4. The sofa leather is thrashed and polished to obtain high-property thrashing highlights, and the thrashing time is 8 hours.

[0053] Performance testing 1. Anti-wear performance test Three samples were taken from Example 1-Example 2 and Comparative Example 1, and then the wear resistance of the samples was tested with reference to GB / T43818.1-2024 "Determination of the wear resistance of leather Part 1: Taber method", and the test data are shown in Table 1.

[0054] Table 1 Anti-wear performance test table of Example 1-Example 2 and Comparative Example 1

[0055] 2. Softness test Three samples were taken out from Example 1-Example 2 and Comparative Example 1 respectively, and cut into 70mm×45mm samples. Then, the folding angle was set to 22.5±0.5°, the folding frequency was 100 times / min, and the folding was 10,000 times. The surface state of the sample was observed, and the test data is shown in Table 2.

[0056] Table 2 Softness test table of Example 1-Example 2 and Comparative Example 1

[0057] 3. Yellowing resistance test Three samples were taken from Examples 2 to 7 respectively, and then placed at a temperature of 129° C. for 12 hours. The fastness grades of the samples were then measured with reference to GB / T250-2008 “Grey Scale for Assessing Color Change in Textile Color Fastness Tests”. The test data are shown in Table 3.

[0058] Table 3 Yellowing resistance performance data table of Example 2 to Example 7

[0059] 4. Stability Test Three samples were taken out from Example 5 and Example 8 respectively, and then placed at room temperature for 50 days to observe the stratification of the samples; then three more samples were taken out and placed at 50°C for 50 days to observe the stratification of the samples. The experimental data are shown in Table 4.

[0060] Table 4 Stability data table of Example 5 and Example 8

[0061] With reference to Example 1 and Comparative Example 1 and in combination with Tables 1 and 2, it can be seen that, relative to Comparative Example 1, the number of cycles and softness of Example 1 are significantly improved, which indicates that, relative to the use of paraffin, the use of beeswax can further improve the wear resistance and softness of the sofa leather brightener.

[0062] The reason is that beeswax contains ester components, which enable the beeswax molecules to form a tighter and more orderly arrangement, and the intermolecular force is stronger. In addition, beeswax has a higher hardness and a certain rigidity, which enables the high physical property sofa leather brightener to better resist external forces when subjected to friction and is not easily worn. At the same time, it has better softness and is not prone to cracking.

[0063] The molecular structure of paraffin is relatively simple, and the intermolecular force is relatively weak, which makes it easier for the molecules of the high-physical property sofa leather brightener to slide or shift when rubbed, making it more susceptible to wear, and even scratches and peeling.

[0064] Referring to Example 1-Example 2 and combining with Table 1-Table 2, it can be seen that, compared with Example 1, the number of cycles and softness of Example 2 are further improved, which shows that, compared with the tumbling bright spot process, the hot spot process can further improve the wear resistance and softness of the sofa leather brightener. Moreover, compared with the tumbling bright spot process, the hot spot process takes less time. The process time of the tumbling bright spot is nearly 8 hours, while the process time of the hot spot is only 1 hour, which significantly improves the operation time of the bright spot process and improves the efficiency of sofa leather preparation.

[0065] With reference to Example 2 to Example 5 and in combination with Table 3, it can be seen that relative to Example 5, the fastness grades of Example 2 to Example 4 are significantly reduced, which indicates that, relative to the use of 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and didodecyl thiodipropionate alone, when 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and didodecyl thiodipropionate are used in combination, the sofa leather brightener will have better yellowing resistance.

[0066] The reason is that when nitrocellulose varnish is subjected to high temperature aging, some unstable bonds (such as ester bonds) in the nitrocellulose molecules break, and the alkyl parts connected to these bonds may be separated in the form of free radicals to form alkyl free radicals. The alkyl free radicals are further oxidized to form peroxy free radicals, which then capture hydrogen atoms in the nitrocellulose varnish to form new alkyl free radicals and hydroperoxides, thereby further accelerating the yellowing of the nitrocellulose varnish.

[0067] (2-Hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate can capture alkyl radicals and inhibit the aging of nitrocellulose varnish from the root elements, while 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine can capture peroxy radicals and didodecyl thiodipropionate can capture hydroperoxides. Therefore, when the three are used in combination, antioxidant treatment will be carried out at three different stages of aging of nitrocellulose varnish, thereby further reducing the possibility of yellowing of sofa leather brightener.

[0068] With reference to Example 5 to Example 7 and in combination with Table 3, it can be seen that relative to Example 5, the fastness grades of Example 6 to Example 7 are slightly decreased, which indicates that when 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and didodecyl thiodipropionate adopt the mass ratio of Example 5, the prepared sofa leather brightener will have better yellowing resistance.

[0069] Referring to Example 5 and Example 8 and combining with Table 4, it can be seen that, relative to Example 5, although Example 8 did not delaminate within 50 days at room temperature, delamination occurred in Example 8 under an environment of 50°C for 50 days, that is, the addition of nonylphenol polyoxyethylene ether can effectively improve the thermal stability of the sofa leather brightener.

[0070] The reason is that beeswax is a non-polar or weakly polar substance, while nitrocellulose varnish is a polar substance. The polarity difference between the two is large, and the intermolecular force is small, so it is difficult for them to dissolve in each other or mix evenly. As a result, after the leather brightener is left for a long time, stratification is likely to occur. In a hot storage environment, the molecular movement of beeswax and nitrocellulose varnish will be more active, further causing stratification.

[0071] Nonylphenol polyoxyethylene ether has both hydrophilic groups and lipophilic groups. This structure can significantly reduce the surface tension of the liquid. When nonylphenol polyoxyethylene ether is added to antioxidant polyurethane, and antioxidant polyurethane is added to sofa leather brightener, nonylphenol polyoxyethylene ether will be oriented, with the hydrophilic groups facing the water phase and the lipophilic groups facing the oil phase, thereby reducing the tension of the oil-water interface, allowing beeswax and nitrocellulose varnish to be evenly dispersed in water and form a stable emulsion, thereby effectively reducing the possibility of stratification of the sofa leather brightener after long-term storage.

[0072] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A sofa leather brightener with high physical properties, characterized in that: The invention comprises the following raw materials in parts by weight: 30-40 parts of nitrocellulose varnish, 30-40 parts of beeswax, 10-15 parts of polyethylene wax and 10-15 parts of wound repairing ointment.

2. The high-property sofa leather brightener according to claim 1, characterized in that The wound-repairing ointment comprises the following raw materials in parts by weight: 50-60 parts of antioxidant polyurethane emulsion, 2-4 parts of filling material, 1-3 parts of thickener, 1-3 parts of defoamer and 20-50 parts of deionized water, wherein the antioxidant polyurethane emulsion contains 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and didodecyl thiodipropionate.

3. The high-property sofa leather brightener according to claim 2, characterized in that: The mass ratio of the 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and didodecyl thiodipropionate is (1-3):(2-4):(1-3).

4. The high-property sofa leather brightener according to claim 2, characterized in that: The antioxidant polyurethane also contains nonylphenol polyoxyethylene ether.

5. The high-property sofa leather brightener according to claim 4, characterized in that: The antioxidant polyurethane emulsion comprises the following raw materials in parts by weight: 30-40 parts of waterborne polyurethane emulsion, 10-16 parts of nonylphenol polyoxyethylene ether, 1-3 parts of 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate, 2-4 parts of 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine and 1-3 parts of didodecyl thiodipropionate.

6. The high-property sofa leather brightener according to claim 2, characterized in that: The filling material is one or a mixture of polymer hollow microspheres, kaolin, silicon dioxide, titanium dioxide and light calcium carbonate; and / or; The thickener is one of RM-8W, PU1341 and RHEOLATE 299; and / or; The defoamer is one of YL-801, EFKA SI 2741 and DU-1242.

7. A method for preparing the high-property sofa leather brightener according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: First, mix nitrocellulose varnish and beeswax to obtain a first mixed solution; Step 2: mixing the first mixed solution with polyethylene wax to obtain a second mixed solution; Step 3: Mix the second mixed liquid with the repairing ointment to obtain a sofa leather brightener with high physical properties.

8. A coating process for the high-property sofa leather brightener according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Spray the high-property sofa leather brightener evenly on the surface of the sofa leather, and control the spraying thickness to 1-3g per square foot; S2. Transfer the sofa leather into an oven and heat at 90-110°C for 2-4 hours; S3. Place the sofa leather at room temperature for 6-8 hours to form a stable coating layer; S4. Perform tumbling treatment on the sofa leather at 100-120°C to obtain hot spots with high physical properties.

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