A biodegradable water-based plastic-replacing oil and its preparation method

Abstract

The present invention relates to a biodegradable water-based plastic replacement oil and its preparation method, belonging to the technical field of water-based plastic replacement oils. The biodegradable water-based plastic replacement oil comprises the following components: a modified water-based polyurethane emulsion, a water-based acrylic emulsion, wax powder, matting agent, a defoaming agent, a silane coupling agent, propylene glycol, and deionized water. The present invention utilizes titanium dioxide for modification, improving its dispersibility and compatibility while enabling it to participate in system reactions, significantly enhancing the mechanical properties and high-temperature resistance of the water-based plastic replacement oil.

Description

Technical Field

[0001] The invention belongs to the technical field of water-based plastic-replacing oils and relates to a biodegradable water-based plastic-replacing oil and a preparation method thereof. Background Art

[0002] Water-based plastic replacement oil is an innovative, environmentally friendly material designed to replace traditional plastic film. This material is not only environmentally friendly but also provides the same level of protection as traditional plastic film.

[0003] Water-based plastic replacement oils are biodegradable, effectively reducing environmental pollution. Compared to traditional plastic film, they avoid the waste of resources involved in waste paper disposal. They exhibit advantages such as high tension and tensile strength, strength, abrasion resistance, fold and riot resistance, water resistance, and aging resistance. They also exhibit excellent ink adhesion, exhibiting no sticking and strong adhesion. Water-based plastic replacement oils are suitable for coating packaging paperboard in various industries, including the medical, electronics, cosmetics, and education sectors. In the printing industry, they can achieve effects similar to laminating and film coating, and are suitable for a variety of equipment, including inline printing presses, full-sheet UV printers, standard oiling machines, and spot UV printers for thin paper. Compared to traditional plastic replacement oils, water-based plastic replacement oils offer significant environmental advantages. Traditional plastic replacement oils are often based on petrochemical raw materials and are difficult to degrade, while water-based plastic replacement oils utilize biodegradable raw materials, making them more compliant with modern environmental standards. Summary of the Invention

[0004] The purpose of the present invention is to provide a biodegradable water-based plastic replacement oil and a preparation method thereof. The present invention modifies titanium dioxide to change its dispersibility and compatibility while enabling it to participate in the reaction of the system, thereby significantly improving the mechanical properties and high-temperature resistance of the water-based plastic replacement oil.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A biodegradable water-based plastic-replacing oil comprises the following components in parts by weight:

[0007] 70-82 parts of modified water-based polyurethane emulsion, 15-21 parts of water-based acrylic emulsion, 2-4 parts of wax powder, 2-4 parts of matting powder, 0.3-0.5 parts of defoaming agent, 1.2-1.8 parts of silane coupling agent, 2-3 parts of propylene glycol and 20-40 parts of deionized water.

[0008] As a preferred technical solution of the present invention, the solid content of the aqueous acrylic emulsion is 35-45%, and the pH value is 7-9.

[0009] As a preferred technical solution of the present invention, the wax powder is PE wax with a particle size of 2-5 μm.

[0010] As a preferred technical solution of the present invention, the matting powder is Degussa TS-100; and the defoaming agent is TEGO Airex 904W.

[0011] As a preferred technical solution of the present invention, the silane coupling agent is one or more of silane coupling agent KH550, silane coupling agent KH560 and silane coupling agent KH570.

[0012] As a preferred technical solution of the present invention, the preparation method of the modified polyurethane emulsion comprises the following steps:

[0013] After preheating the polyether diol, diisocyanate and an organic tin catalyst are added and stirred to react to obtain a prepolymer. 2,2-dihydroxymethylpropionic acid and modified titanium dioxide are added to the prepolymer to continue the reaction. 1,4-butanediol is added, and after cooling, triethylamine and deionized water are added and dispersed to obtain a modified waterborne polyurethane emulsion.

[0014] As a preferred technical solution of the present invention, in the preparation of the modified polyurethane emulsion, the preheating is heating to a temperature of 60-80°C; the stirring reaction time is 2-4 hours; the continued reaction is reacting at a temperature of 60-80°C for 4-6 hours; and the cooling is cooling to 25-40°C.

[0015] As a preferred technical solution of the present invention, in the preparation of the modified polyurethane emulsion, the polyether diol, diisocyanate, organotin catalyst, 2,2-dihydroxymethylpropionic acid, modified titanium dioxide, 1,4-butanediol, triethylamine and deionized water are in a ratio of 20-30:8-15:0.15-0.16:2-4:2.4-3.0:1.2-2.0:5-8:60-70; the polyether diol is PPG3000; the diisocyanate is one or more of IPDI, TDI, MDI and HMDI; and the organotin catalyst is dibutyltin laurate.

[0016] As a preferred technical solution of the present invention, the preparation method of the modified titanium dioxide comprises the following steps:

[0017] S1. After mixing titanium dioxide and isobutanol, adding chitosan solution, ultrasonic treatment, and standing to obtain a mixed solution;

[0018] S2. Under an inert atmosphere, the mixed solution, anhydrous ethanol and composite monomer are heated and stirred, filtered, washed and vacuum dried to obtain an intermediate object;

[0019] S3. After mixing the intermediate object with anhydrous ethanol, adding thioglycerol and a photoinitiator and treating with ultraviolet radiation, centrifuging and collecting the solid, washing, and vacuum drying to obtain modified titanium dioxide.

[0020] As a preferred technical solution of the present invention, in step S1, the ultrasonic treatment is performed at a power of 600-800 W for 40-50 minutes; the standing time is 2-3 hours; the mass ratio of the titanium dioxide, isobutanol, and chitosan solution is 16-17:0.8-1.0:85-90; the chitosan solution is prepared by mixing chitosan and acetic acid solution in a mass ratio of 1.2:18-20; and the mass fraction of the acetic acid solution is 3%.

[0021] As a preferred technical solution of the present invention, in step S2, the inert atmosphere is a nitrogen atmosphere; the heating and stirring is stirring at a temperature of 56-65°C and a speed of 400-600 rpm for 6-8 hours; the washing is washing with anhydrous ethanol three times and then washing with deionized water twice; the vacuum drying is vacuum drying at a temperature of 80-90°C to constant weight; the mass ratio of the mixed solution, anhydrous ethanol and composite monomer is 120:8-10:2.8-3.2; and the composite monomer is composed of citral and 5-hydroxymethylfurfural in a mass ratio of 4.2-4.6:2.3-2.5.

[0022] As a preferred technical solution of the present invention, in step S3, the ultraviolet irradiation treatment is ultraviolet irradiation at a wavelength of 365nm for 10-12h; the washing is washing with anhydrous ethanol three times; the vacuum drying is vacuum drying at a temperature of 80-90°C for 8-10h; the mass ratio of the intermediate object, anhydrous ethanol, thioglycerol and photoinitiator is 15-18:50-60:2.8-3.2:0.09-0.11; and the photoinitiator is photoinitiator 1173.

[0023] A method for preparing a biodegradable water-based plastic-replacing oil comprises the following steps:

[0024] Stir wax powder, matting powder, propylene glycol, silane coupling agent and deionized water at 600-800 rpm for 15-20 minutes, add modified waterborne polyurethane emulsion and waterborne acrylic emulsion and continue stirring for 8-10 minutes, add defoaming agent and stir at 1000-1200 rpm for 5-8 minutes to obtain the product.

[0025] Beneficial effects of the present invention:

[0026] The present invention forms a stable self-assembled network structure through titanium dioxide and chitosan, significantly improving the dispersion effect of titanium dioxide, and then grafts citral, 5-hydroxymethylfurfural and thioglycerol to participate in the reaction of the system, significantly improving the mechanical properties and high temperature resistance of the water-based plastic replacement oil. DETAILED DESCRIPTION

[0027] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments. Example 1

[0028] A biodegradable water-based plastic-replacing oil comprises the following components in parts by weight:

[0029] 70 parts of modified water-based polyurethane emulsion, 15 parts of water-based acrylic emulsion, 2 parts of wax powder, 2 parts of matting powder, 0.3 parts of defoaming agent, 1.2 parts of silane coupling agent, 2 parts of propylene glycol and 20 parts of deionized water;

[0030] The solid content of the aqueous acrylic emulsion is 35% and the pH value is 7;

[0031] The wax powder is PE wax with a particle size of 2 μm;

[0032] The silane coupling agent is silane coupling agent KH550.

[0033] The preparation method of the modified polyurethane emulsion comprises the following steps:

[0034] After preheating the polyether diol, diisocyanate and an organotin catalyst are added and stirred to react to obtain a prepolymer, 2,2-dihydroxymethylpropionic acid and modified titanium dioxide are added to the prepolymer to continue the reaction, 1,4-butanediol is added, the temperature is lowered, and triethylamine and deionized water are added and dispersed to obtain a modified waterborne polyurethane emulsion;

[0035] Among them, the preheating is heating to 60°C; the stirring reaction time is 2 hours; the continued reaction is reacting at 60°C for 4 hours; the cooling is cooling to 25°C; the polyether diol, diisocyanate, organic tin catalyst, 2,2-dihydroxymethylpropionic acid, modified titanium dioxide, 1,4-butanediol, triethylamine and deionized water are 20:8:0.15:2:2.4:1.2:5:60; the polyether diol is PPG3000; the diisocyanate is IPDI; the organic tin catalyst is dibutyltin laurate.

[0036] The preparation method of the modified titanium dioxide comprises the following steps:

[0037] S1. After mixing titanium dioxide and isobutanol, chitosan solution is added and ultrasonically treated, and the mixture is allowed to stand to obtain a mixed solution; wherein the ultrasonic treatment is performed at a power of 600 W for 40 minutes; the standing time is 2 hours; the mass ratio of the titanium dioxide, isobutanol, and chitosan solution is 16:0.8:85; the chitosan solution is prepared by mixing chitosan and acetic acid solution in a mass ratio of 1.2:18; the mass fraction of the acetic acid solution is 3%;

[0038] S2. Under an inert atmosphere, the mixed liquid, anhydrous ethanol and composite monomer are heated and stirred, and then filtered, washed and vacuum dried to obtain an intermediate object; wherein, the inert atmosphere is a nitrogen atmosphere; the heating and stirring is stirring at 56°C and 400 rpm for 6 hours; the washing is washing with anhydrous ethanol 3 times and then washing with deionized water 2 times; the vacuum drying is vacuum drying at 80°C to constant weight; the mass ratio of the mixed liquid, anhydrous ethanol and composite monomer is 120:8:2.8; the composite monomer is composed of citral and 5-hydroxymethylfurfural in a mass ratio of 4.2:2.3.

[0039] S3. After mixing the intermediate object and anhydrous ethanol, add thioglycerol and a photoinitiator and treat with ultraviolet light. Centrifuge to obtain the solid, wash it, and vacuum dry it to obtain modified titanium dioxide. The ultraviolet irradiation treatment is ultraviolet irradiation at a wavelength of 365nm for 10 hours. The washing is washing with anhydrous ethanol three times. The vacuum drying is vacuum drying at a temperature of 80°C for 8 hours. The mass ratio of the intermediate object, anhydrous ethanol, thioglycerol and photoinitiator is 15:50:2.8:0.09.

[0040] A method for preparing a biodegradable water-based plastic-replacing oil comprises the following steps:

[0041] After stirring wax powder, matting powder, propylene glycol, silane coupling agent and deionized water at 600 rpm for 15 minutes, modified waterborne polyurethane emulsion and waterborne acrylic emulsion are added and stirred for 8 minutes, and defoaming agent is added and stirred for 5 minutes at 1000 rpm to obtain the product. Example 2

[0042] A biodegradable water-based plastic-replacing oil comprises the following components in parts by weight:

[0043] 76 parts of modified waterborne polyurethane emulsion, 18 parts of waterborne acrylic emulsion, 3 parts of wax powder, 3 parts of matting powder, 0.4 parts of defoaming agent, 1.5 parts of silane coupling agent, 2.5 parts of propylene glycol and 30 parts of deionized water;

[0044] The solid content of the aqueous acrylic emulsion is 40% and the pH value is 8;

[0045] The wax powder is PE wax with a particle size of 4 μm;

[0046] The silane coupling agent is silane coupling agent KH550.

[0047] The preparation method of the modified polyurethane emulsion comprises the following steps:

[0048] After preheating the polyether diol, diisocyanate and an organotin catalyst are added and stirred to react to obtain a prepolymer, 2,2-dihydroxymethylpropionic acid and modified titanium dioxide are added to the prepolymer to continue the reaction, 1,4-butanediol is added, the temperature is lowered, and triethylamine and deionized water are added and dispersed to obtain a modified waterborne polyurethane emulsion;

[0049] Among them, the preheating is heating to 70°C; the stirring reaction time is 3 hours; the continued reaction is reacting at 70°C for 5 hours; the cooling is cooling to 32°C; the polyether diol, diisocyanate, organic tin catalyst, 2,2-dihydroxymethylpropionic acid, modified titanium dioxide, 1,4-butanediol, triethylamine and deionized water are 25:12:0.155:3:2.7:1.6:6:65; the polyether diol is PPG3000; the diisocyanate is IPDI; the organic tin catalyst is dibutyltin laurate.

[0050] The preparation method of the modified titanium dioxide comprises the following steps:

[0051] S1. After mixing titanium dioxide and isobutanol, chitosan solution is added and ultrasonically treated, and the mixture is allowed to stand to obtain a mixed solution; wherein the ultrasonic treatment is performed at a power of 700 W for 45 minutes; the standing time is 2.5 hours; the mass ratio of titanium dioxide, isobutanol and chitosan solution is 16.5:0.9:88; the chitosan solution is prepared by mixing chitosan and acetic acid solution in a mass ratio of 1.2:19; the mass fraction of the acetic acid solution is 3%;

[0052] S2. Under an inert atmosphere, the mixed liquid, anhydrous ethanol and composite monomer are heated and stirred, and then filtered, washed and vacuum dried to obtain an intermediate object; wherein, the inert atmosphere is a nitrogen atmosphere; the heating and stirring is stirring at 60°C and 500 rpm for 7 hours; the washing is washing with anhydrous ethanol 3 times and then washing with deionized water 2 times; the vacuum drying is vacuum drying at 85°C to constant weight; the mass ratio of the mixed liquid, anhydrous ethanol and composite monomer is 120:9:3; the composite monomer is composed of citral and 5-hydroxymethylfurfural in a mass ratio of 4.4:2.4.

[0053] S3. After mixing the intermediate object and anhydrous ethanol, add thioglycerol and a photoinitiator and treat with ultraviolet light. Centrifuge to obtain the solid, wash it, and vacuum dry it to obtain modified titanium dioxide. The ultraviolet irradiation treatment is ultraviolet irradiation at a wavelength of 365nm for 11 hours. The washing is washing with anhydrous ethanol three times. The vacuum drying is vacuum drying at a temperature of 85°C for 9 hours. The mass ratio of the intermediate object, anhydrous ethanol, thioglycerol and photoinitiator is 16:55:3:0.1.

[0054] A method for preparing a biodegradable water-based plastic-replacing oil comprises the following steps:

[0055] After stirring wax powder, matting powder, propylene glycol, silane coupling agent and deionized water at 700 rpm for 18 minutes, modified waterborne polyurethane emulsion and waterborne acrylic emulsion are added and stirred for 9 minutes, and defoaming agent is added and stirred at 1100 rpm for 6 minutes to obtain the product. Example 3

[0056] A biodegradable water-based plastic-replacing oil comprises the following components in parts by weight:

[0057] 82 parts of modified waterborne polyurethane emulsion, 21 parts of waterborne acrylic emulsion, 4 parts of wax powder, 4 parts of matting powder, 0.5 parts of defoaming agent, 1.8 parts of silane coupling agent, 3 parts of propylene glycol and 40 parts of deionized water;

[0058] The solid content of the aqueous acrylic emulsion is 45% and the pH value is 9;

[0059] The wax powder is PE wax with a particle size of 5 μm;

[0060] The silane coupling agent is silane coupling agent KH550.

[0061] The preparation method of the modified polyurethane emulsion comprises the following steps:

[0062] After preheating the polyether diol, diisocyanate and an organotin catalyst are added and stirred to react to obtain a prepolymer, 2,2-dihydroxymethylpropionic acid and modified titanium dioxide are added to the prepolymer to continue the reaction, 1,4-butanediol is added, the temperature is lowered, and triethylamine and deionized water are added and dispersed to obtain a modified waterborne polyurethane emulsion;

[0063] Among them, the preheating is heating to 80°C; the stirring reaction time is 4 hours; the continued reaction is reacting at 80°C for 6 hours; the cooling is cooling to 40°C; the polyether diol, diisocyanate, organic tin catalyst, 2,2-dihydroxymethylpropionic acid, modified titanium dioxide, 1,4-butanediol, triethylamine and deionized water are 30:15:0.16:4:3.0:2.0:8:70; the polyether diol is PPG3000; the diisocyanate is IPDI; the organic tin catalyst is dibutyltin laurate.

[0064] The preparation method of the modified titanium dioxide comprises the following steps:

[0065] S1. After mixing titanium dioxide and isobutanol, chitosan solution is added and ultrasonically treated, and the mixture is allowed to stand to obtain a mixed solution; wherein the ultrasonic treatment is performed at an 800W power for 50 minutes; the standing time is 3 hours; the mass ratio of the titanium dioxide, isobutanol, and chitosan solution is 17:1.0:90; the chitosan solution is prepared by mixing chitosan and acetic acid solution in a mass ratio of 1.2:20; the mass fraction of the acetic acid solution is 3%;

[0066] S2. Under an inert atmosphere, the mixed liquid, anhydrous ethanol and composite monomer are heated and stirred, and then filtered, washed and vacuum dried to obtain an intermediate object; wherein, the inert atmosphere is a nitrogen atmosphere; the heating and stirring is stirring at 65°C and 600 rpm for 8 hours; the washing is washing with anhydrous ethanol 3 times and then washing with deionized water 2 times; the vacuum drying is vacuum drying at 90°C to constant weight; the mass ratio of the mixed liquid, anhydrous ethanol and composite monomer is 120:10:3.2; the composite monomer is composed of citral and 5-hydroxymethylfurfural in a mass ratio of 4.6:2.5.

[0067] S3. After mixing the intermediate object and anhydrous ethanol, add thioglycerol and a photoinitiator and treat with ultraviolet light. Centrifuge to obtain the solid, wash it, and vacuum dry it to obtain modified titanium dioxide. The ultraviolet irradiation treatment is ultraviolet irradiation at a wavelength of 365nm for 12 hours. The washing is washing with anhydrous ethanol three times. The vacuum drying is vacuum drying at a temperature of 90°C for 10 hours. The mass ratio of the intermediate object, anhydrous ethanol, thioglycerol and photoinitiator is 18:60:3.2:0.11.

[0068] A method for preparing a biodegradable water-based plastic-replacing oil comprises the following steps:

[0069] After stirring wax powder, matting powder, propylene glycol, silane coupling agent and deionized water at 800 rpm for 20 minutes, modified waterborne polyurethane emulsion and waterborne acrylic emulsion are added and stirred for 10 minutes, and defoaming agent is added and stirred at 1200 rpm for 8 minutes to obtain the product. Example 4

[0070] Compared with Example 3, Example 4 is different in that the silane coupling agent is silane coupling agent KH560, and the other components, preparation steps and parameters are the same.

[0071] Comparative Example 1

[0072] Compared with Example 3, Comparative Example 1 is different in that chitosan is not used, and the other components, preparation steps and parameters are the same.

[0073] Comparative Example 2

[0074] Compared with Example 3, the difference in Comparative Example 2 is that the composite monomer is citral, and the other components, preparation steps and parameters are the same.

[0075] Comparative Example 3

[0076] Compared with Example 3, Comparative Example 3 is different in that the composite monomer is 5-hydroxymethylfurfural, and the other components, preparation steps and parameters are the same.

[0077] Comparative Example 4

[0078] Compared with Example 3, the difference of Comparative Example 4 is that no composite monomer is used, and the other components, preparation steps and parameters are the same

[0079] Comparative Example 5

[0080] Compared with Example 3, Comparative Example 5 is different in that thioglycerol is not used, and the other components, preparation steps and parameters are the same.

[0081] The water-based plastic-displacing oils prepared in Examples 1-4 and Comparative Examples 1-5 were subjected to the following performance tests, and the test results are shown in Table 1.

[0082] Hardness test: According to GB / T6739-2006 pencil hardness test, the pencil is pressed down at a 45° angle under a load of 500g;

[0083] High temperature resistance test: bake the sample at 150℃ for 1 hour and observe the surface of the cured film;

[0084] Table 1

[0085]

[0086] From the test results in Table 1, it can be seen that, compared with Comparative Examples 1-5, the water-based plastic-displacing oil prepared in Examples 1-4 has excellent mechanical properties and high-temperature resistance after solidification.

[0087] This method uses isobutanol as the dispersion medium and ultrasonically treats titanium dioxide and chitosan to promote the penetration of chitosan into the titanium dioxide. Through hydrogen bonding and electrostatic interactions, chitosan and titanium dioxide form a self-assembled, stable network structure. In this structure, chitosan acts as a bridge, significantly improving the dispersion of titanium dioxide within the system. Subsequently, by introducing citral and 5-hydroxymethylfurfural containing aldehyde groups, they react with the amino groups in the chitosan molecules to form Schiff base bonds, thereby constructing a network-like cross-linked structure. Now, the mechanical properties and high-temperature resistance of the water-based plastic substitute are increased. The hydrogen bonding between the hydroxyl groups of 5-hydroxymethylfurfural and chitosan is utilized to make the layered stacking structure of the cross-linked composite material become tighter. 5-Hydroxymethylfurfural contains a high-temperature resistant furan structure. Combined with the hydrophobic carbon chain of citral, the non-polarity and hydrophobicity of the mixed monomer are utilized to jointly improve the stability of the modified titanium dioxide and the dispersibility of the modified titanium dioxide in the water-based plastic substitute system. In addition, the modified titanium dioxide, due to the introduction of unsaturated carbon-carbon double bonds, participates in the copolymerization reaction of the system. Combined with the grafted thioglycerol, it contains multiple active hydroxyl groups and can react chemically with diisocyanates, thereby increasing the binding force of the modified titanium dioxide, water-based polyurethane emulsion, and water-based acrylic emulsion system, and significantly improving its mechanical properties and high-temperature resistance.

[0088] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any indirect modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A biodegradable water-based plastic-replacing oil, characterized in that: The following components are included in parts by weight: 70-82 parts of modified waterborne polyurethane emulsion, 15-21 parts of waterborne acrylic emulsion, 2-4 parts of wax powder, 2-4 parts of matting powder, 0.3-0.5 parts of defoaming agent, 1.2-1.8 parts of silane coupling agent, 2-3 parts of propylene glycol and 20-40 parts of deionized water; The preparation method of the modified aqueous polyurethane emulsion comprises the following steps: After preheating the polyether diol, diisocyanate and an organotin catalyst are added and stirred to react to obtain a prepolymer, 2,2-dihydroxymethylpropionic acid and modified titanium dioxide are added to the prepolymer to continue the reaction, 1,4-butanediol is added, the temperature is lowered, and triethylamine and deionized water are added and dispersed to obtain a modified waterborne polyurethane emulsion; The preparation method of the modified titanium dioxide comprises the following steps: S1. After mixing titanium dioxide and isobutanol, adding chitosan solution, ultrasonic treatment, and standing to obtain a mixed solution; S2. Under an inert atmosphere, heating and stirring the mixed solution, anhydrous ethanol, and a composite monomer, followed by suction filtration, washing, and vacuum drying to obtain an intermediate object; the composite monomer is composed of citral and 5-hydroxymethylfurfural in a mass ratio of 4.2-4.6:2.3-2.5; S3. After mixing the intermediate object with anhydrous ethanol, adding thioglycerol and a photoinitiator and treating with ultraviolet radiation, centrifuging and collecting the solid, washing, and vacuum drying to obtain modified titanium dioxide.

2. The biodegradable aqueous plastic-displacing oil according to claim 1, characterized in that: The solid content of the aqueous acrylic emulsion is 35-45%, and the pH value is 7-9; the wax powder is PE wax with a particle size of 2-5 μm; and the silane coupling agent is one or more of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

3. The biodegradable aqueous plastic-displacing oil according to claim 1, characterized in that: In the preparation of the modified waterborne polyurethane emulsion, the preheating is heating to 60-80°C; the stirring reaction time is 2-4 hours; the continued reaction is reacting at 60-80°C for 4-6 hours; and the cooling is cooling to 25-40°C.

4. The biodegradable aqueous plastic-displacing oil according to claim 1, characterized in that: In the preparation of the modified waterborne polyurethane emulsion, the ratio of the polyether diol, diisocyanate, organotin catalyst, 2,2-dihydroxymethylpropionic acid, modified titanium dioxide, 1,4-butanediol, triethylamine and deionized water is 20-30:8-15:0.15-0.16:2-4:2.4-3.0:1.2-2.0:5-8:60-70; the polyether diol is PPG3000; and the diisocyanate is one or more of IPDI, TDI, MDI and HMDI.

5. The biodegradable aqueous plastic-displacing oil according to claim 1, characterized in that: In step S1, the ultrasonic treatment is performed at a power of 600-800 W for 40-50 minutes; the standing time is 2-3 hours; the mass ratio of the titanium dioxide, isobutanol, and chitosan solution is 16-17:0.8-1.0:85-90; the chitosan solution is prepared by mixing chitosan and acetic acid solution in a mass ratio of 1.2:18-20; and the mass fraction of the acetic acid solution is 3%.

6. The biodegradable aqueous plastic-displacing oil according to claim 1, characterized in that: In step S2, the inert atmosphere is a nitrogen atmosphere; the heating and stirring is stirring at a temperature of 56-65°C and a speed of 400-600 rpm for 6-8 hours; the washing is washing with anhydrous ethanol 3 times and then washing with deionized water 2 times; the vacuum drying is vacuum drying at a temperature of 80-90°C to constant weight.

7. The biodegradable aqueous plastic-displacing oil according to claim 1, characterized in that: In step S2, the mass ratio of the mixed liquid, anhydrous ethanol and composite monomer is 120:8-10:2.8-3.

2.

8. The biodegradable aqueous plastic-displacing oil according to claim 1, characterized in that: In step S3, the ultraviolet irradiation treatment is ultraviolet irradiation at a wavelength of 365 nm for 10-12 hours; the washing is washing with anhydrous ethanol for 3 times; and the vacuum drying is vacuum drying at a temperature of 80-90° C. for 8-10 hours.

9. The biodegradable aqueous plastic-displacing oil according to claim 1, characterized in that: In step S3, the mass ratio of the intermediate object, anhydrous ethanol, thioglycerol and photoinitiator is 15-18:50-60:2.8-3.2:0.09-0.

11.

10. A method for preparing the biodegradable aqueous plastic-displacing oil according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: stirring wax powder, matting powder, propylene glycol, silane coupling agent and deionized water at a speed of 600-800 rpm for 15-20 minutes, adding modified waterborne polyurethane emulsion and waterborne acrylic emulsion and continuing to stir for 8-10 minutes, adding defoaming agent and stirring at a speed of 1000-1200 rpm for 5-8 minutes to obtain the product.

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