Preparation method of negundo chastetree fruit microcapsule and application of negundo chastetree fruit microcapsule in mosquito repellent finishing of fabric

Abstract

The invention discloses a preparation method of a negundo chastetree fruit microcapsule and application of the negundo chastetree fruit microcapsule in mosquito-repellent finishing of fabrics. Vitex negundo essential oil is used as a core material, an emulsifier and a wall material are investigated, it is determined that Tween-80 is used as the emulsifier, gelatin and sodium alginate are used as the wall material, a complex coacervation method and calcium chloride cross-linking curing are adopted, and freeze drying is performed to obtain the Vitex negundo microcapsule. By optimizing the emulsifier addition amount, the total wall material concentration, the core-wall ratio and the like, the embedding rate of the prepared rhizoma polygonati microcapsule can reach 75% or above, the particle size is smaller than 2 microns, and the rhizoma polygonati microcapsule can be stably and uniformly dispersed in water. The negundo chastetree fruit microcapsule is prepared into a finishing liquid which is used for after-finishing of fabrics, can endow the fabrics with good mosquito repelling performance, and is fresh in smell and free of anaphylactic reaction.

Description

Technical Field

[0001] The invention belongs to the technical field of application of natural plant essential oils, and particularly relates to a preparation method of vitex negundo microcapsules and application of the microcapsules in mosquito repellent finishing of fabrics. Background Art

[0002] The spread of diseases caused by mosquitoes is very disturbing. With the continuous change of global climate, the continuous melting of glaciers and the continuous rise of sea levels, the spread of diseases mediated by mosquitoes is becoming more and more widespread. The vast majority of infectious diseases transmitted by mosquitoes currently have no vaccines or specific drugs to effectively protect against them. The use of pesticides to control mosquitoes is the most widely used method. Pesticides include organic pesticides, inorganic pesticides, botanical pesticides, and microbial pesticides. With the rapid development of modernization, the use of pesticides is becoming more and more widespread. However, the use of too much organic pesticides can easily cause soil pollution, thereby changing the balance of the ecosystem, making it difficult for some species to survive and increasing the drug resistance of some pests. The use of low-pollution plants for control has become a research focus in recent years.

[0003] Vitex negundo L. is a plant of the genus Vitex in the Verbenaceae family. Vitex negundo essential oil is a volatile oil extracted from the branches, leaves, flowers and fruits of Vitex negundo, and has a special fragrance. Vitex negundo essential oil contains a variety of chemical components, including terpenes, flavonoids, lignans and their derivatives. Vitex negundo essential oil has the effects of expectorant, cough relief and asthma relief, and can be used to treat chronic bronchitis. Vitex negundo has a good repellent effect on mosquitoes, but there are few studies on its repellent properties against mosquitoes. my country has abundant wild Vitex negundo resources, so Vitex negundo has great development potential as a mosquito repellent plant.

[0004] Since plant essential oils are unstable and volatile, microencapsulation can be used to maintain the performance and biological activity of plant essential oils. Complex coacervation is a method of using two or more oppositely charged polymer materials as wall materials, adjusting the pH of the solution to cause cross-linking and coagulation with the core material to form microcapsules. Summary of the invention

[0005] In order to make up for the lack of application of Vitex negundo in mosquito repelling, the present invention aims to provide a preparation method of Vitex negundo microcapsules and application of the microcapsules in mosquito repellent finishing of fabrics.

[0006] In order to solve the above technical problems and achieve the purpose of the invention, the present invention adopts the following technical solutions: The first aspect of the present invention provides a method for preparing microcapsules of Vitex negundo, comprising the following specific steps: (1) Preparation of wall material A: Add gelatin into distilled water to dissolve to prepare a gelatin aqueous solution; Preparation of wall material B: Add sodium alginate into distilled water to dissolve to prepare a sodium alginate aqueous solution; wherein the mass fraction of the gelatin aqueous solution is 0.5-2.5%, the mass fraction of the sodium alginate aqueous solution is 0.5-2.5%, and the mass fraction of the sodium alginate aqueous solution is 0.5-2.5%, and the total mass concentration of the wall materials is controlled to be 0.5%-2.5%.

[0007] (2) Weighing the essential oil of Vitex negundo and the surfactant, mixing them evenly, adding them into the aqueous gelatin solution, and stirring them homogeneously to obtain an emulsion; Among them, the addition amount of surfactant is 1.5% of the mass of essential oil, the homogenization speed is 10000rpm, the homogenization time is 3min~11min, and the mass ratio of core material to wall material is 1:0.5~2.

[0008] (3) Slowly add the sodium alginate aqueous solution to the emulsion, stir evenly, and then use 10% acetic acid solution to adjust the pH value of the solution for complex coagulation reaction; The mass ratio of gelatin to sodium alginate is 5:1, the stirring speed is 1000 r / min, the pH of the complex coagulation reaction is 4.2, the complex coagulation reaction temperature is 40° C., and the complex coagulation reaction time is 50 min.

[0009] (4) After the complex coagulation reaction is completed, cool to below 10°C and slowly add 1% calcium chloride solution to solidify; Among them, the curing time is 60 minutes.

[0010] (5) After solidification, wash and filter with distilled water, and then freeze-dry to obtain the Vitex negundo microcapsule powder.

[0011] As a preferred technical solution of the present invention, in step (1), the total wall material mass concentration is 1% to 1.5%, and more preferably 1%.

[0012] As a preferred technical solution of the present invention, in step (2), the surfactant is any one of Tween-80, Span-20 and Span-80; Tween-80 is further preferred.

[0013] As a preferred technical solution of the present invention, in step (2), the homogenization time is 3 to 7 minutes, more preferably 3 to 5 minutes, and more preferably 5 minutes.

[0014] As a preferred technical solution of the present invention, in step (2), the mass ratio of the core material to the wall material is 1:0.5-1.5; more preferably 1:0.67-1; and even more preferably 1:1.

[0015] As a preferred technical solution of the present invention, in step (5), the freeze-drying temperature is -80°C and the freeze-drying time is 24 hours.

[0016] The second aspect of the present invention provides the use of the vitex negundo microcapsules prepared by the above preparation method in mosquito repellent finishing of fabrics.

[0017] Specifically, the vitex negundo microcapsules are prepared into finishing liquid, which is used for fabric post-finishing to obtain mosquito-repellent fabric.

[0018] The vitex negundo microcapsules can be directly dispersed in water to obtain a mosquito repellent finishing liquid; or the vitex negundo microcapsules, adhesive, penetrant and water are prepared into a mosquito repellent finishing liquid; the mass concentration of the vitex negundo microcapsules in the mosquito repellent finishing liquid is 1-5%.

[0019] Among them, the adhesive includes but is not limited to water-based polyurethane, acrylate, etc., and its added amount accounts for 3~7% of the mass of the mosquito repellent finishing liquid; the penetrant includes but is not limited to sodium fatty alcohol polyoxyethylene ether sulfate, sodium alkylbenzene sulfonate, etc., and its added amount accounts for 1~3% of the mass of the mosquito repellent finishing liquid.

[0020] Furthermore, the above-mentioned fabric finishing method includes spraying the mosquito repellent finishing liquid directly on the surface of the fabric (such as non-woven fabric); or first immersing the fabric (such as cotton fabric) in the finishing liquid, and then performing padding and baking treatment to obtain the mosquito repellent fabric.

[0021] Compared with the existing technology, the present invention has the following beneficial technical effects: The present invention is a method for preparing a vitex microcapsule for fabric finishing, wherein the vitex essential oil with mosquito repellent performance is used as a core material, gelatin and sodium alginate are used as composite wall materials, and the vitex mosquito repellent microcapsule powder is obtained by homogenization emulsification, complex coacervation reaction, solidification, and freeze drying. This technology fills the gap in the research direction of the mosquito repellent performance of vitex essential oil. The use of microcapsule technology can improve the sustained release performance of the essential oil and increase the mosquito repellent time of vitex essential oil. The core material and wall material used in the present invention are both environmentally friendly materials, meet the industrial needs of green development, and have good application prospects. The preparation method of the vitex microcapsule of the present invention is simple, and the raw materials are green. It is used for fabric finishing, can give textiles good mosquito repellent performance, and has a fresh smell and is friendly to human skin. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a scanning electron microscope image of the Vitex negundo microcapsules prepared in Example 1 of the present invention.

[0023] Figure 2 Schematic diagram of the mosquito repellent performance testing device used in the present invention. DETAILED DESCRIPTION

[0024] The present invention is further described in detail in conjunction with the following specific examples, and the protection scope of the present invention is not limited to the following examples. The process, conditions, reagents, experimental methods, etc. for implementing the present invention, except for the contents specifically mentioned below, are all common knowledge and common common sense in the art, and the present invention has no special restrictions.

[0025] The vitex negundo essential oil used in the following examples of the present invention is extracted according to the method of CN118028055A.

[0026] The test methods used in the following examples of the present invention are as follows: 1. The method for determining the microcapsule embedding rate is as follows: The maximum absorption wavelength of Vitex negundo essential oil was measured by ultraviolet spectrophotometer; the absorbance of ethanol solutions of Vitex negundo essential oil of different concentrations was measured at the maximum absorption wavelength, and a standard curve was drawn.

[0027] Surface oil: Weigh a certain amount of microcapsule powder, add anhydrous ethanol, shake evenly and centrifuge, take the supernatant and dilute it and measure its absorbance, and calculate the essential oil content on the surface of the prepared microcapsule according to the standard curve of Vitex negundo essential oil.

[0028] Total oil: Weigh a certain amount of microcapsule powder, add anhydrous ethanol, shake evenly, and then ultrasonicate. Centrifuge after the ultrasonication, take the supernatant and dilute it to measure its absorbance. According to the standard curve of Vitex negundo essential oil, calculate the essential oil content contained in the prepared microcapsules. The embedding rate of the microcapsules is calculated according to the following formula.

[0029] Embedding rate (%) = (1- m1 / m2) × 100 Wherein, m1 is the mass of microcapsule surface oil / g, and m2 is the mass of total oil in the initial microcapsule / g.

[0030] 2. The mosquito repellent performance test method is as follows: Mosquitoes caught in the wild were temporarily raised in mosquito cages at 26°C and 60% relative humidity. The finished fabrics were first placed in box A, and the unfinished fabrics were placed in box C. Then 50 mosquitoes were placed in box B through the insect release port. After 3 minutes, the partition was removed. After 10 minutes, the number of mosquitoes staying in boxes A and C was observed. The mosquito repellent rate was calculated as follows:

[0031] Among them, m1 is the number of mosquitoes staying in box C; m2 is the number of mosquitoes staying in box A. Example 1

[0032] (1) Preparation of wall material A: Weigh 1.0 g of gelatin and add it to distilled water to dissolve, and prepare a 1.0% gelatin solution for later use; Preparation of wall material B: Weigh 0.2 g of sodium alginate and add it to distilled water to dissolve, and prepare a 1.0% sodium alginate solution for later use; (2) Weigh 1.2 g of Vitex negundo essential oil and Tween-80 (1.5% by weight of Vitex negundo essential oil), mix well, add to the gelatin aqueous solution, and homogenize and stir at 10,000 rpm for 5 min using a high-speed homogenizer; (3) Place the homogenized emulsion in a constant temperature magnetic stirring water bath, slowly add sodium alginate aqueous solution until complete, stir evenly at 1000 r / min at 40°C, slowly add 10% acetic acid solution to adjust the solution pH to 4.2, and perform complex coagulation reaction for 50 minutes; (4) After the complex coagulation reaction is completed, cool to below 10°C, slowly add 1% calcium chloride solution, and solidify for 60 minutes; (5) After solidification, wash and filter with distilled water, and then freeze-dry to obtain the Vitex negundo microcapsule powder.

[0033] According to the method for measuring the embedding rate of microcapsules, the embedding rate of the microcapsules prepared in this embodiment is 75.30%. The average particle size of the prepared microcapsules measured by Malvern particle size analyzer is 1010 nm. Figure 1 This is a scanning electron microscope image of the microcapsules prepared in Example 1. Example 2

[0034] Compared with Example 1, Example 2 studied the effect of the homogenization time in step (2) on the microcapsule embedding efficiency, while other conditions were the same as those in Example 1.

[0035] Table 1. Effect of different homogenization time on microcapsule embedding efficiency Example 3

[0036] Compared with Example 1, Example 3 studies the effect of the total wall material concentration on the microcapsule embedding efficiency in steps (1) to (2), while other conditions are the same as those in Example 1.

[0037] Table 2. Effect of different total wall material concentrations on microcapsule embedding efficiency Example 4

[0038] Compared with Example 1, Example 4 studies the effect of the core-to-wall ratio on the microcapsule embedding efficiency in step (2), while other conditions are the same as those in Example 1.

[0039] Table 3. Effect of different core-to-wall ratios on microcapsule embedding efficiency Comparative Example 1

[0040] The difference between this comparative example and Example 1 is that the wall material A is: 1.0 g of chitosan is weighed and added into distilled water to dissolve, and a 1.0% chitosan solution is prepared for use. The remaining steps are the same as those in Example 1.

[0041] According to the method for measuring the embedding rate of microcapsules, the embedding rate of the microcapsules prepared in this comparative example is 67.21%. The particle size is measured by using a Malvern particle size analyzer, and the average particle size of the microcapsules prepared in this comparative example is 1665 nm. Comparative Example 2

[0042] The difference between this comparative example and Example 1 is that Tween-80 is not added in step (2), and the remaining steps are the same as those in Example 1.

[0043] According to the method for measuring the embedding rate of microcapsules, the embedding rate of the microcapsules prepared in this comparative example is 65.71%. The particle size is measured by using a Malvern particle size analyzer, and the average particle size of the microcapsules prepared in this comparative example is 1733 nm. Comparative Example 3

[0044] The surfactant used in the emulsification process in this comparative example is Span-20, and the specific preparation method is as follows: (1) Preparation of wall material A: Weigh 1.0 g of gelatin and add it to distilled water to dissolve, and prepare a 1.0% gelatin solution for later use; Preparation of wall material B: Weigh 0.2 g of sodium alginate and add it to distilled water to dissolve, and prepare a 1.0% sodium alginate solution for later use; (2) Weigh 0.8 g of Vitex negundo essential oil and Span-20 (1.5% by weight of Vitex negundo essential oil), mix well, add to the gelatin aqueous solution, and homogenize and stir at 10,000 rpm for 5 min using a high-speed homogenizer; (3) Place the homogenized emulsion in a constant temperature magnetic stirring water bath, slowly add sodium alginate aqueous solution until complete, stir evenly at 1000 r / min at 40°C, slowly add 10% acetic acid solution to adjust the solution pH to 4.2, and perform complex coagulation reaction for 50 minutes; (4) After the complex coagulation reaction is completed, cool to below 10°C, slowly add 1% calcium chloride solution, and solidify for 60 minutes; (5) After solidification, wash and filter with distilled water, and then freeze-dry to obtain the Vitex negundo microcapsule powder.

[0045] According to the method for measuring the embedding rate of microcapsules, the embedding rate of the microcapsules prepared in this comparative example is 66.92%. The particle size is measured by using a Malvern particle size analyzer, and the average particle size of the microcapsules prepared in this comparative example is 1593 nm. Comparative Example 4

[0046] The difference between this comparative example and comparative example 3 is that the surfactant used in the emulsification process is Span-80. The specific preparation method is as follows: (1) Preparation of wall material A: Weigh 1.0 g of gelatin and add it to distilled water to dissolve, and prepare a 1.0% gelatin solution for later use; Preparation of wall material B: Weigh 0.2 g of sodium alginate and add it to distilled water to dissolve, and prepare a 1.0% sodium alginate solution for later use; (2) Weigh 0.8 g of Vitex negundo essential oil and Span-80 (1.5% by weight of Vitex negundo essential oil), mix well, add to the gelatin aqueous solution, and homogenize and stir at 10,000 rpm for 5 min using a high-speed homogenizer; (3) Place the homogenized emulsion in a constant temperature magnetic stirring water bath, slowly add sodium alginate aqueous solution until complete, stir evenly at 1000 r / min at 40°C, slowly add 10% acetic acid solution to adjust the solution pH to 4.2, and perform complex coagulation reaction for 50 minutes; (4) After the complex coagulation reaction is completed, cool to below 10°C, slowly add 1% calcium chloride solution, and solidify for 60 minutes; (5) After solidification, wash and filter with distilled water, and then freeze-dry to obtain the Vitex negundo microcapsule powder.

[0047] According to the method for measuring the embedding rate of microcapsules, the embedding rate of the microcapsules prepared in this comparative example is 69.92%. The particle size is measured by using a Malvern particle size analyzer, and the average particle size of the microcapsules prepared in this comparative example is 1157 nm. Application Example 1

[0048] The yellow vitex mosquito repellent microcapsules prepared in Example 1 and Comparative Examples 1-4 were used for finishing of cotton fabrics, and the specific method was as follows: Preparation of fabrics finished with Huangjing mosquito repellent microcapsules: Weigh the Huangjing mosquito repellent microcapsule powder prepared in the present invention and disperse it in water, then add the adhesive waterborne polyurethane and the penetrant fatty alcohol polyoxyethylene ether sodium sulfate and disperse them uniformly by ultrasonication, wherein the solid content of the microcapsules is 3% of the total mass of the system, the amount of the adhesive added is 5% of the total mass of the system, and the amount of the penetrant added is 1% of the total mass of the system. Dip the cotton fabric in it, take it out after 2 minutes, and do two dips and two rollings, with a rolling rate of 85%. Bake at 110°C to obtain a cotton fabric with mosquito repellent performance, and conduct a mosquito repellent test on the obtained cotton fabric.

[0049] Table 4. Mosquito repellent effect of the finished cotton fabrics Application Example 2

[0050] The yellow vitex mosquito repellent microcapsules prepared in Example 1 and Comparative Examples 1-4 were used for post-finishing of non-woven fabrics, and the specific method was as follows: Preparation of fabrics finished with Huangjing mosquito repellent microcapsules: Weigh the Huangjing mosquito repellent microcapsule powder prepared in the present invention and disperse it in water to prepare a mosquito repellent spray preparation, wherein the solid content of the microcapsules is 3% of the total mass of the system. Spray it on non-woven fabrics and dry it at room temperature to obtain non-woven fabrics with mosquito repellent properties, and conduct mosquito repellent tests on the obtained non-woven fabrics.

[0051] Table 5. Mosquito repellent effect of nonwoven fabric after finishing

[0052] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing microcapsules of Vitex negundo, characterized in that: The specific steps include: (1) Preparation of wall material A: adding gelatin into distilled water to dissolve to prepare a gelatin aqueous solution; preparation of wall material B: adding sodium alginate into distilled water to dissolve to prepare a sodium alginate aqueous solution; wherein the total mass concentration of the wall material is controlled to be 0.5%~2.5%; (2) mixing the vitex negundo essential oil and the surfactant evenly, adding the mixture to the gelatin aqueous solution, and stirring the mixture to obtain an emulsion; wherein the amount of the surfactant added is 1.5% of the mass of the vitex negundo essential oil, the homogenization speed is 10000 rpm, the homogenization time is 3 min to 11 min, and the mass ratio of the core material to the wall material is 1:0.5 to 2; (3) Slowly add the sodium alginate aqueous solution to the emulsion, stir evenly, and then adjust the pH value to 4.0-4.5 with 10% acetic acid solution to carry out complex coagulation reaction; (4) After the complex coagulation reaction is completed, cool to below 10°C and slowly add 1% calcium chloride solution to solidify; (5) After solidification, wash and filter with distilled water, and then freeze-dry to obtain the Vitex negundo microcapsule powder.

2. The method for preparing the Vitex negundo microcapsules according to claim 1, characterized in that: The mass ratio of the gelatin to the sodium alginate is 5:

1.

3. The method for preparing the Vitex negundo microcapsules according to claim 1, characterized in that: In step (1), the total wall material mass concentration is 1% to 1.5%.

4. The method for preparing the Vitex negundo microcapsules according to claim 1, characterized in that: In step (2), the mass ratio of the core material to the wall material is 1:0.5~1.

5.

5. The method for preparing the Vitex negundo microcapsules according to claim 1, characterized in that: In step (2), the surfactant is any one of Tween-80, Span-20 and Span-80.

6. The method for preparing the Vitex negundo microcapsules according to claim 1, characterized in that: In step (2), the homogenization time is 3 to 5 minutes.

7. The method for preparing the Vitex negundo microcapsules according to claim 1, characterized in that: The stirring speed in step (3) is 1000 r / min, the pH of the complex coagulation reaction is 4.2, the complex coagulation reaction temperature is 40° C., and the complex coagulation reaction time is 50 min.

8. The method for preparing the Vitex negundo microcapsules according to claim 1, characterized in that: In step (5), the freeze-drying temperature is -80°C and the freeze-drying time is 24 hours.

9. Use of the Vitex negundo microcapsules prepared by the method according to any one of claims 1 to 8 in mosquito repellent finishing of fabrics, characterized in that: The microcapsules of Vitex negundo are prepared into mosquito repellent finishing liquid, and the fabric is post-finished to obtain mosquito repellent fabric.

10. The use according to claim 9, characterized in that: The mass concentration of the Vitex negundo microcapsules in the mosquito repellent finishing liquid is 1-5%.

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