Essential oil sustained-release microcapsule as well as preparation method and application thereof

Abstract

The invention relates to the technical field of essential oil microcapsules, and provides an essential oil sustained-release microcapsule as well as a preparation method and application thereof. According to the preparation method, a polyurethane prepolymer, hydroxyl silicone oil and essential oil are taken as main raw materials, and the essential oil-coated sustained-release microcapsule is prepared by interfacial polymerization. The essential oil sustained-release microcapsule provided by the invention has a fragrance sustained-release function and lasting antibacterial performance, has a wide application prospect, can be applied to fabric products, leather products, paper products and the like, and has good washing and rubbing fastness on the fabric products.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of essential oil microcapsules, in particular to an essential oil slow-release microcapsule and a preparation method and application thereof. BACKGROUND

[0002] Plant essential oil is a volatile oil liquid substance with strong fragrance extracted from aromatic plants, which is complex in composition and diverse in structure, mainly composed of aromatic compounds such as alcohols, ethers, aldehydes, ketones and esters. Essential oil not only has a pleasant fragrance, but also has many medical and health care effects, usually showing antibacterial, antioxidant and other biological activities. However, essential oil is difficult to dissolve in water, volatile, easily oxidized, has a strong irritating odor at high concentration, and the biological activity is extremely unstable under high humidity, high temperature and light conditions, which greatly limits its practical application.

[0003] People are eager to find a method that can protect essential oil substances for a long time, improve their stability and processability. Microencapsulation is a technology that uses natural or synthetic substances to encapsulate solids, liquids or gases. After microencapsulation, essential oil is wrapped by the capsule wall, which can prevent external environmental interference, thereby avoiding the loss of volatile active ingredients, making essential oil easy to store, safe and convenient to use, greatly improving the fragrance retention time, durability and stability of essential oil.

[0004] In the prior art, there are many methods for preparing fragrance microcapsules, including miniemulsion polymerization, in-situ polymerization, complex coacervation, interfacial polymerization and spray drying. Chinese invention patent (application number: 201110006254.0) provides a preparation method of fragrance microcapsules, which improves the compactness of the capsule wall and the tolerance to solution acidity and alkalinity by adding a crosslinking agent to treat the capsule wall, thereby improving the stability of the application of fragrance microcapsules. However, this method has many processes, and the corresponding control conditions are strict, which is not conducive to ensuring the quality of the product. Chinese invention patent (application number: 201610338140.9) provides a preparation method of microcapsules with fragrance slow-release function, which double-coats the fragrance with gelatin, gum arabic and porous shell powder. Based on the double capsule wall, the microcapsules can release fragrance for a long time. The preparation process of this method is complicated, and the coating amount is limited. Most importantly, the fastness of these microcapsules for textiles such as washing and rubbing is low. Therefore, it is of great significance to realize the improvement of the stability and slow-release performance of essential oil for the development and utilization of essential oil products and the development of essential oil industry. SUMMARY

[0005] In view of the above technical problems, the purpose of the present application is to provide an essential oil slow-release microcapsule and a preparation method and application thereof.

[0006] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions:

[0007] A preparation method of an essential oil sustained-release microcapsule, comprising the following steps:

[0008] mixing essential oil, polyurethane prepolymer, hydroxyl silicone oil, diethylenetriamine, emulsifier and deionized water, and performing dispersion treatment to obtain an emulsion; performing a capsule forming reaction on the obtained emulsion to obtain an essential oil sustained-release microcapsule,

[0009] wherein the polyurethane prepolymer is prepared by reacting isophorone diisocyanate, polyethylene glycol and 2-chloro-3', 4'-dihydroxyacetophenone under the action of a catalyst.

[0010] Further, the mass ratio of the essential oil, polyurethane prepolymer, hydroxyl silicone oil, diethylenetriamine, emulsifier and deionized water is 10-50:10-60:1-20:0.5-5:0.5-10:100-2000.

[0011] Further, the dispersion treatment is performed at a rotation speed of 5000-20000 for 2-8 min.

[0012] Further, the reaction temperature of the capsule forming reaction is 40-80℃, and the reaction time is 4-10 h.

[0013] Further, the essential oil is one or a mixture of several of jasmine essential oil, lily essential oil, mint essential oil, lavender essential oil, wormwood essential oil, osmanthus essential oil, violet essential oil, carvacrol, thymol, lemon oil, Asian mint essential oil, laurel leaf oil, patchouli oil, geranium oil or perilla oil.

[0014] Further, the essential oil is at least one of carvacrol, thymol, lemon oil, Asian mint essential oil, laurel leaf oil, patchouli oil, geranium oil and perilla oil.

[0015] Further, the essential oil is a mixture of carvacrol, thymol, lemon oil, Asian mint essential oil, laurel leaf oil, patchouli oil, geranium oil and perilla oil.

[0016] Further, the essential oil is composed of components with the following mass percentages: 5% of carvacrol, 5% of thymol, 35% of lemon oil, 30% of Asian mint essential oil, 10% of laurel leaf oil, 0.5% of patchouli oil, 5% of geranium oil and 9.5% of perilla oil. The essential oil is named Herbal Antibacterial / Bacteriostasis Essential Oil HABO, Essential Oil HABO or HABO( Herbal Antibacterial / Bacteriostasis Essential Oil).

[0017] Further, the polyurethane prepolymer has a molecular weight of 3000-8000; and the hydroxyl silicone oil has a molecular weight of 800-2000.

[0018] Further, the emulsifier is one or a mixture of several of polyoxyethylene-8-octylphenyl ether, sorbitan oleate, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, dodecyl ammonium chloride, N-dodecyl dimethylamine, sodium dodecyl benzene sulfonate or sodium dodecyl sulfate.

[0019] Further, the polyurethane prepolymer is prepared by using isophorone diisocyanate, polyethylene glycol and 2-chloro-3', 4'-dihydroxyacetophenone as raw materials in a molar ratio of 1:0.4:0.2, using dibutyltin dilaurate as a catalyst, using acetone as a solvent, reacting at 60℃ for 2h, and removing the excess acetone, wherein the polyethylene glycol has a molecular weight of 400-2000.

[0020] The application further provides an essential oil slow-release microcapsule prepared by the above-mentioned method for preparing an essential oil slow-release microcapsule.

[0021] Compared with the prior art, the method for preparing an essential oil microcapsule provided by the application uses essential oil as a core material, and a polyurethane prepolymer and a hydroxyl silicone oil as main raw materials for forming a microcapsule shell layer by interfacial polymerization, so the preparation method is simple and easy to operate. Based on the design of the chemical composition of the shell layer and the coating of the essential oil, the stability of the essential oil is improved, the essential oil in the finally obtained microcapsule can be released slowly for a long time, the microcapsule has a fragrance slow-release function, and has a wide application prospect.

[0022] In addition, the application further provides applications of the above-mentioned essential oil slow-release microcapsule in fabric finishing and in preparing leather products and paper products.

[0023] Further, the fabric includes woven fabric, knitted fabric or non-woven fabric.

[0024] Further, the essential oil slow-release microcapsule is finished on the fabric by padding, dipping, coating or spraying.

[0025] After the fabric is dipped into the microcapsule emulsion for 0.5-2h, the fabric is dried at 40-80℃ for 2-10min to obtain the fabric finished by the microcapsule.

[0026] The essential oil slow-release microcapsule provided by the application can be applied to fabric products, leather products, paper products and the like. Based on the specific design of the chemical composition of the microcapsule shell layer, the washing and rubbing fastness of the microcapsule on the fabric product are significantly improved, the fabric product is endowed with persistent fragrance and persistent antibacterial performance, and has a wider application value. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 SEM image of the essential oil sustained-release microcapsule of the embodiment of the present application;

[0028] Figure 2 SEM image of the fabric after finishing with the microcapsule of the embodiment of the present application;

[0029] Figure 3 Graph of the residual amount of essential oil after washing of the fabric after finishing with the microcapsule and the fabric after finishing with essential oil of the embodiment of the present application. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below with examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application.

[0031] Example 1

[0032] A method for preparing an essential oil sustained-release microcapsule, comprising the following steps:

[0033] 30 parts of essential oil (HABO), 30 parts of polyurethane prepolymer (molecular weight 3000), 10 parts of hydroxyl silicone oil (molecular weight 800), 2.5 parts of divinyltriamine, 5 parts of sodium dodecyl benzene sulfonate and 1000 parts of deionized water are mixed and dispersed in a homogenizer at a speed of 10000 rpm for 5 minutes to obtain an emulsion, and then the emulsion is reacted at 60℃ for 6 hours to obtain the essential oil sustained-release microcapsule.

[0034] The essential oil consists of the following components in mass percentage: 5% of carvacol, 5% of thymol, 35% of lemon oil, 30% of Asian peppermint oil, 10% of laurel leaf oil, 0.5% of patchouli oil, 5% of geranium oil and 9.5% of perilla oil.

[0035] The polyurethane prepolymer is prepared by the following method: 6 parts of isophorone diisocyanate, 4.3 parts of polyethylene glycol (molecular weight: 400), 1 part of 2-chloro-3', 4'-dihydroxyacetophenone and 0.1 part of dibutyltin dilaurate are dissolved in 40 parts of acetone, and reacted at 60℃ for 2h. The obtained product is obtained by removing excess acetone.

[0036] After the viscose fabric is immersed in the obtained microcapsule emulsion for 1 hour, it is dried in a 60℃ oven for 5 minutes to obtain the fabric after finishing with the microcapsule.

[0037] Example 2

[0038] A method for preparing an essential oil sustained-release microcapsule, comprising the following steps:

[0039] Mix 10 parts of jasmine flower essential oil, 10 parts of polyurethane prepolymer (molecular weight 8000), 1 part of hydroxyl silicone oil (molecular weight 2000), 0.5 part of divinyl triamine, 0.5 part of polyoxyethylene sorbitan fatty acid ester and 100 parts of deionized water, and then disperse the mixture in a homogenizer at a speed of 5000 rpm for 2 minutes to obtain an emulsion. The emulsion is then reacted at 40°C for 10 hours to obtain the essential oil sustained-release microcapsule.

[0040] The polyurethane prepolymer is prepared by the following method: 6 parts of isophorone diisocyanate, 21.5 parts of polyethylene glycol (molecular weight 2000), 1 part of 2-chloro-3', 4'-dihydroxyacetophenone and 0.1 part of dibutyl tin dilaurate are dissolved in 40 parts of acetone, and the mixture is reacted at 60°C for 2 hours. The obtained product is then dried to remove excess acetone.

[0041] The viscose fiber cloth is immersed in the microcapsule emulsion for 2 hours, and then dried in an oven at 80°C for 2 minutes to obtain the microcapsule finished fabric.

[0042] Example 3

[0043] A method for preparing an essential oil sustained-release microcapsule, comprising the following steps:

[0044] Mix 20 parts of peppermint essential oil, 20 parts of polyurethane prepolymer (molecular weight 5000), 6 parts of hydroxyl silicone oil (molecular weight 1000), 1.5 parts of divinyl triamine, 3 parts of polyoxyethylene-8-octyl phenyl ether and 600 parts of deionized water, and then disperse the mixture in a homogenizer at a speed of 8000 rpm for 4 minutes to obtain an emulsion. The emulsion is then reacted at 50°C for 8 hours to obtain the essential oil sustained-release microcapsule.

[0045] The polyurethane prepolymer is prepared by the following method: 6 parts of isophorone diisocyanate, 10.8 parts of polyethylene glycol (molecular weight 1000), 1 part of 2-chloro-3', 4'-dihydroxyacetophenone and 0.1 part of dibutyl tin dilaurate are dissolved in 40 parts of acetone, and the mixture is reacted at 60°C for 2 hours. The obtained product is then dried to remove excess acetone.

[0046] The viscose fiber cloth is immersed in the microcapsule emulsion for 1.5 hours, and then dried in an oven at 70°C for 3 minutes to obtain the microcapsule finished fabric.

[0047] Example 4

[0048] A method for preparing an essential oil sustained-release microcapsule, comprising the following steps:

[0049] Lavender essential oil 40 parts, polyurethane prepolymer (molecular weight 4000) 50 parts, hydroxyl silicone oil (molecular weight 800) 17 parts, divinyl triamine 4 parts, sodium dodecyl sulfate 8 parts and deionized water 1700 parts are mixed and dispersed in a homogenizer at a speed of 12000 rpm for 7 minutes to obtain an emulsion, and the emulsion is then reacted at 70°C for 5 hours to obtain the essential oil slow-release microcapsule.

[0050] The polyurethane prepolymer is prepared by the following method: 6 parts of isophorone diisocyanate, 8.6 parts of polyethylene glycol (molecular weight 800), 1 part of 2-chloro-3', 4'-dihydroxyacetophenone and 0.1 part of dibutyltin dilaurate are dissolved in 40 parts of acetone, and the mixture is reacted at 60°C for 2 hours. The obtained product is then dried to remove excess acetone.

[0051] The viscose fiber cloth is immersed in the microcapsule emulsion for 1 hour, and then dried in an oven at 50°C for 4 minutes to obtain the microcapsule finished fabric.

[0052] Example 5

[0053] A method for preparing an essential oil slow-release microcapsule, comprising the following steps:

[0054] Artemisia oil 50 parts, polyurethane prepolymer (molecular weight 6000) 60 parts, hydroxyl silicone oil (molecular weight 1500) 20 parts, divinyl triamine 5 parts, dodecyl ammonium chloride 10 parts and deionized water 2000 parts are mixed and dispersed in a homogenizer at a speed of 20000 rpm for 8 minutes to obtain an emulsion, and the emulsion is then reacted at 40°C for 10 hours to obtain the essential oil slow-release microcapsule.

[0055] The polyurethane prepolymer is prepared by the following method: 6 parts of isophorone diisocyanate, 12 parts of polyethylene glycol (molecular weight 1200), 1 part of 2-chloro-3', 4'-dihydroxyacetophenone and 0.1 part of dibutyltin dilaurate are dissolved in 40 parts of acetone, and the mixture is reacted at 60°C for 2 hours. The obtained product is then dried to remove excess acetone.

[0056] The viscose fiber cloth is immersed in the microcapsule emulsion for 0.5 hours, and then dried in an oven at 40°C for 10 minutes to obtain the microcapsule finished fabric.

[0057] Comparative Example 1

[0058] A method for preparing an essential oil microcapsule, comprising the following steps:

[0059] Mixing essential oil (HABO) 30 parts, polyurethane prepolymer (molecular weight 3000) 30 parts, polyethylene glycol (molecular weight 800) 10 parts, divinyl triamine 2.5 parts, polyvinyl alcohol 5 parts and deionized water 500 parts, then disperse in a homogenizer at a speed of 10000 rpm for 5 minutes to obtain an emulsion, and then react the emulsion at 40°C for 8 hours to obtain the essential oil microcapsule.

[0060] In the formula, the essential oil and the polyurethane prepolymer are the same as in Example 1.

[0061] After the viscose fiber cloth is immersed in the above obtained microcapsule emulsion for 1 hour, it is placed in an oven at 60°C for drying for 5 minutes to obtain the microcapsule finished fabric.

[0062] Comparative Example 2

[0063] A method for preparing an essential oil microcapsule, comprising the following steps:

[0064] Mixing essential oil (HABO) 30 parts, polyurethane prepolymer (molecular weight 2000) 30 parts, hydroxyl silicone oil (molecular weight 800) 10 parts, divinyl triamine 2.5 parts, sodium dodecyl benzene sulfonate 5 parts and deionized water 1000 parts, then disperse in a homogenizer at a speed of 10000 rpm for 5 minutes to obtain an emulsion, and then react the emulsion at 60°C for 6 hours to obtain the essential oil microcapsule.

[0065] In the formula, the essential oil is the same as in Example 1, and the polyurethane prepolymer is prepared by the same method as in Example 1.

[0066] After the viscose fiber cloth is immersed in the above obtained microcapsule emulsion for 1 hour, it is placed in an oven at 60°C for drying for 5 minutes to obtain the microcapsule finished fabric.

[0067] Comparative Example 3

[0068] A method for preparing an essential oil microcapsule, comprising the following steps:

[0069] Mixing essential oil (HABO) 30 parts, polyurethane prepolymer 30 parts, hydroxyl silicone oil (molecular weight 800) 10 parts, divinyl triamine 2.5 parts, sodium dodecyl benzene sulfonate 5 parts and deionized water 1000 parts, then disperse in a homogenizer at a speed of 10000 rpm for 5 minutes to obtain an emulsion, and then react the emulsion at 60°C for 4 hours to obtain the essential oil microcapsule.

[0070] In the formula, the essential oil is the same as in Example 1; the polyurethane prepolymer is prepared by replacing isophorone diisocyanate with an equal molar amount of toluene-3,5-diisocyanate based on Example 1.

[0071] After immersing the viscose fiber cloth in the microcapsule emulsion obtained above for 1 hour, it is dried in a 60°C oven for 5 minutes to obtain the microcapsule-treated fabric.

[0072] Experimental Example 1

[0073] The essential oil sustained-release microcapsules prepared in Example 1 and the fabric treated with the microcapsules obtained in Example 1 were subjected to scanning electron microscopy.

[0074] like Figure 1 As shown, the morphology of the essential oil sustained-release microcapsules prepared in Example 1 was observed by scanning electron microscopy. The particle size of the microcapsules was 8-10 μm.

[0075] like Figure 2 As shown in Example 1, the microstructure of the fabric surface after microcapsule treatment can be seen. There are many microcapsules between the fabric fibers, and the microcapsules cover the fabric surface.

[0076] Experimental Example 2

[0077] The absorbance was measured in the 200-800 nm range using a UV-Vis-NIR spectrophotometer (U-4100, Hitachi) to test the essential oil sustained-release performance of the microcapsule-treated fabrics obtained in Example 1 and Comparative Examples 1, 2, and 3. The absorbance was measured using a spectrophotometer at different concentrations (0.1 mg / mL). -1 0.2 mg·mL -1 0.3 mg·mL -1 0.4 mg·mL -1 0.5 mg·mL -1 The absorbance of the essential oil-ethanol solution was tested. The absorbance data at the maximum absorption wavelength was selected, and data fitting was performed using Origin to obtain a standard curve and linear regression equation for the essential oil absorbance. The treated fabric (0.200g) was placed in a constant temperature incubator and immersed in 20mL of ethanol at different times (1, 15, 30, 45, 60, 75, and 90 days). The absorbance of the corresponding ethanol was measured, and then converted to essential oil concentration using the standard curve to determine the residual amount of essential oil on the fabric at different times.

[0078] After testing and calculation, the data on the residual essential oil content of the fabrics treated with microcapsules in Examples 1, 2, and 3 after different placement times were obtained, and the results are shown in the table below.

[0079] Table 1. Essential oil residue after different storage times.

[0080]

[0081] From the above data, compared with the comparative example, the microcapsule finished fabric obtained by the embodiment of the application still has more than 30% of the essential oil residue after being placed for 3 months, which shows that the specific design of the shell layer chemical composition and the coating of the essential oil in the application achieve effective barrier effect and realize slow release of the essential oil.

[0082] The essential oil residue data of the microcapsule finished fabric of the embodiment and the comparative examples 1, 2 and 3 after different washing times are obtained through test calculation, and the results are shown in the following table.

[0083] Table 2 Essential oil residue after different washing times

[0084]

[0085] Compared with the comparative example, the essential oil residue of the microcapsule finished fabric of the application still remains more than 75% after 10 times of washing, which shows that the washing fastness of the microcapsule on the fabric surface is high. In addition, the essential oil residue of the fabric finished by the microcapsule of the embodiment 1 and the essential oil finished by the embodiment 1 after different washing times is compared, and the results are shown in Table 3. Figure 3 The washing and rubbing fastness of the essential oil slow-release microcapsule is significantly improved through the design of the microcapsule, which further verifies that the microcapsule on the fabric surface can endow the fabric with long-lasting fragrance and long-lasting antibacterial performance.

[0086] Test example 3

[0087] The microcapsule finished fabric prepared in the embodiment 1 is subjected to antibacterial performance test, and the test method refers to GB-T20944.3-2008 “Evaluation of Antibacterial Performance of Textiles Part 3: Oscillation Method”. The specific method is as follows:

[0088] (1) The microcapsule finished fabric prepared in the embodiment 1 is cut into about 5mm*5mm fragments, and then 0.25g is weighed as 1 part and placed in a 100mL conical flask. According to the test requirements, multiple parts are weighed and sterilized by using ultraviolet lamp.

[0089] (2) Prepare bacterial inoculum (Escherichia coli and Staphylococcus aureus) and PBS buffer, and prepare nutrient agar culture medium plate.

[0090] (3) Prepare bacterial suspension: use a bacterial inoculation ring to take a colony from the cultured bacteria, and put it into the conical flask containing the bacterial inoculum, and put it into a shaking bed (temperature: 37℃, speed: 130r / min) and shake for 24 hours.

[0091] (4) Dilution and separation: test the bacterial concentration by using ultraviolet spectrophotometer, and dilute with PBS buffer to control the concentration of the bacterial solution to about 0.4.

[0092] (5) When the concentration is appropriate, take 5 mL of the bacterial solution and dilute it 10 times with PBS buffer solution 2 , and move it into the conical flask containing the fabric, and place it in a shaking bed for 18 h (24℃, 150 r / min).

[0093] (6) After the specified time, take 1 mL of the bacterial solution from the conical flask of step (5), and dilute it to an appropriate dilution fold with PBS buffer solution, take 25 μL respectively and move it into sterilized agar medium plates, and coat it evenly, and finally place the plates in a constant temperature cabinet at 37℃ for 24 h, and record the number of bacteria.

[0094] (7) Calculate the results according to GB-T20944.3-2008, and obtain the inhibition rate.

[0095] The inhibition rates of the microcapsule finished fabric prepared in Example 1 on Staphylococcus aureus and Escherichia coli after different storage times are shown in the following table.

[0096] Table 3

[0097]

[0098] From the above data, it can be seen that the inhibition rates of the microcapsule finished fabric prepared in the example of the present application on Staphylococcus aureus and Escherichia coli after 3 months of storage are still as high as 94.1% and 92.5%, and the antibacterial performance is excellent.

[0099] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement or improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing sustained-release microcapsules of essential oils, characterized in that, The preparation method includes the following steps: Essential oils, polyurethane prepolymers, hydroxyl silicone oils, divinyltriamine, emulsifiers, and deionized water were mixed and dispersed to obtain an emulsion. The resulting emulsion was then subjected to an encapsulation reaction to obtain sustained-release microcapsules of the essential oils. The polyurethane prepolymer is prepared by reacting isophorone diisocyanate, polyethylene glycol and 2-chloro-3′,4′-dihydroxyacetophenone in the presence of a catalyst.

2. The method for preparing essential oil sustained-release microcapsules as described in claim 1, characterized in that, The mass ratio of the essential oil, polyurethane prepolymer, hydroxy silicone oil, divinyltriamine, emulsifier and deionized water is 10-50:10-60:1-20:0.5-5:0.5-10:100-2000.

3. The method for preparing essential oil sustained-release microcapsules as described in claim 1, characterized in that, The dispersion process involves dispersing at a rotation speed of 5000-20000 for 2-8 minutes.

4. The method for preparing essential oil sustained-release microcapsules as described in claim 1, characterized in that, The reaction temperature for the capsule formation reaction is 40-80℃, and the reaction time is 4-10h.

5. The method for preparing essential oil sustained-release microcapsules as described in claim 1, characterized in that, The essential oil is one or a mixture of several of the following: jasmine essential oil, lily essential oil, peppermint essential oil, lavender essential oil, artemisia essential oil, osmanthus essential oil, violet essential oil, carvacrol, thymol, lemon oil, Asian peppermint oil, bay leaf oil, patchouli oil, geranium oil, or perilla oil.

6. The method for preparing essential oil sustained-release microcapsules as described in claim 5, characterized in that, The essential oil is at least one of carvacrol, thymol, lemon oil, Asian peppermint oil, bay leaf oil, patchouli oil, geranium oil, or perilla oil.

7. The method for preparing essential oil sustained-release microcapsules as described in claim 6, characterized in that, The essential oil is a mixture of carvacrol, thymol, lemon oil, Asian peppermint oil, bay leaf oil, patchouli oil, geranium oil, and perilla oil.

8. The method for preparing essential oil sustained-release microcapsules as described in claim 7, characterized in that, The essential oil is composed of the following components in weight percentages: 5% carvacrol, 5% thymol, 35% lemon oil, 30% peppermint oil, 10% bay leaf oil, 0.5% patchouli oil, 5% geranium oil and 9.5% perilla oil.

9. The method for preparing essential oil sustained-release microcapsules as described in claim 1, characterized in that, The molecular weight of the polyurethane prepolymer is 3000-8000; the molecular weight of the hydroxyl silicone oil is 800-2000.

10. The method for preparing essential oil sustained-release microcapsules as described in claim 1, characterized in that, The emulsifier is one or a mixture of several of the following: polyoxyethylene-8-octylphenyl ether, sorbitan oleate, polyoxyethylene sorbitan fatty acid ester, dehydrated sorbitan fatty acid ester, dodecyl ammonium chloride, N-dodecyl dimethylamine, sodium dodecylbenzenesulfonate, or sodium dodecyl sulfate.

11. The method for preparing essential oil sustained-release microcapsules as described in claim 1, characterized in that, The polyurethane prepolymer is prepared by using isophorone diisocyanate, polyethylene glycol and 2-chloro-3′,4′-dihydroxyacetophenone in a molar ratio of 1:0.4:0.2 as raw materials, dibutyltin dilaurate as catalyst, acetone as solvent, reacting at 60°C for 2 hours, and removing excess acetone from the product.

12. A sustained-release microcapsule of essential oil, characterized in that, The essential oil sustained-release microcapsules are prepared by the method described in any one of claims 1 to 11.

13. The application of the essential oil sustained-release microcapsules according to claim 12 in fabric finishing.

14. The application as described in claim 13, characterized in that, The fabrics include woven fabrics, knitted fabrics, or non-woven fabrics.

15. The application as described in claim 14, characterized in that, The essential oil sustained-release microcapsules are applied to the fabric by padding, impregnation, coating, or spraying.

16. The use of the essential oil sustained-release microcapsules according to claim 12 in the preparation of leather products and paper products.

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