A colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition, preparation method and application thereof

Abstract

The present invention relates to the technical field of mosquito repellents, and in particular to a colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition, a preparation method and its application, comprising the following components in mass percentage: DEET 1-25, agar: 1-5, lithium chloride: 0.5-10, water: 50-80, essential oils (citronella, holly, eucalyptus): 0.01-1, food coloring: 0.01-0.1. The composition of the present invention does not contain ethanol, and can avoid the damage to the skin caused by the use of ethanol, as well as the potential safety hazards caused by the ethanol molecules exposed in the air. The mosquito repellent composition of the present invention can automatically absorb water vapor from the air to maintain the moist state of the hydrogel, and the evaporation of water molecules drives the DEET molecules to diffuse into the air, and the mosquito repellent effect can be maintained for more than 4 months. The mosquito repellent composition of the present invention does not need to add a surfactant, and can form a homogeneous system. After the volatilization of DEET is completed, agar in the remaining composition can be naturally degraded, and lithium chloride can be recycled to reduce environmental pollution.

Description

Technical Field

[0001] The invention relates to the technical field of mosquito repellents, and in particular to a colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition, a preparation method and application thereof. Background Art

[0002] DEET (English: Diethyltoluamide, abbreviated as DEET), also known as DEET, DEET, is a yellowish oily liquid, a common ingredient in mosquito repellent, mainly used to repel mosquitoes. DEET is a chemical that has been scientifically proven to have mosquito repellent effects, and its effect is related to concentration. 100% DEET can protect up to 12 hours, and lower concentrations of DEET such as 20%-34% protect for about 3-6 hours. The American Academy of Pediatrics has confirmed that 10-20% DEET can be used directly on children and adults, but it is not recommended for infants under 2 months old, and it cannot be directly in contact with wounds, which may cause neurotoxicity. Traditional theory believes that DEET can interfere with the olfactory receptors of insects and block the sense of insects to emit special odors to humans or animals. Recent scientific research shows that DEET, as a mosquito repellent, works by making mosquitoes feel uncomfortable. At the same time, DEET is a solvent that can be absorbed through the skin, so it is important to use the lowest possible concentration to be effective (10% or less for children) and the smallest possible amount is necessary.

[0003] In recent years, DEET diluted with organic solvents has dominated the market for mosquito repellent products. However, since the organic solvent used to dilute DEET is more easily permeable to the skin, low-concentration DEET is more easily absorbed by the human body. For example, the absorption rate of 15% DEET products by the skin is 20%, while the absorption rate of undiluted DEET by the skin is 12%. Therefore, it is urgent to improve the preparation method of DEET to reduce the contact between DEET and the skin and reduce or eliminate the use of organic solvents.

[0004] Chinese invention patent CN202110437493.5 discloses the use of nitrogen protection, 65-80°C reaction for 5-8h, the use of one of the initiators selected from azobisisoheptanonitrile, azobisisobutyronitrile, dimethyl azobisisobutyrate or dibenzoyl peroxide, and the use of an anionic emulsifier-sodium dodecylbenzene sulfonate as the emulsifier. The prepared capsule-type hydrogel has a mosquito repellent time of 12h and a mosquito repellent rate of 99%. The above characteristic parameters need to be improved for the preparation process conditions of the mosquito repellent hydrogel, and the reaction time is long, which is not conducive to the quantitative production of the product. Moreover, the effective time of the mosquito repellent hydrogel is short, which is difficult to meet practical applications.

[0005] Aqueous mosquito repellents use surfactants to effectively dissolve DEET in water, which not only solves the problem of instability of the DEET solution system, but also effectively solves the adverse effects of organic solvents on the human body. However, in order to maintain the stable state of aqueous mosquito repellents, the additional use of emulsifiers, preservatives, etc. will also lead to increased production costs, especially the secondary environmental pollution caused by the remaining composition after the DEET volatilizes. Therefore, it is necessary to improve the preparation method of existing aqueous mosquito repellents, reduce or eliminate the use of surfactants, and pay attention to the environmental problems of the remaining composition.

[0006] Water-based mosquito repellents are prone to evaporation and water loss during use, causing serious deformation of the sample, reducing the aesthetic effect, and not conducive to maintaining the product's "appearance". At the same time, mosquito repellent compositions are mostly colorless and odorless precursors that cannot attract visual attention. Therefore, it is necessary to improve the preparation method of water-based mosquito repellents to meet consumers' various needs for "appearance", color, and fragrance. In addition, water-based mosquito repellents will inevitably be contaminated by bacteria in the air during use, and are very likely to breed mold, which seriously limits their use environment and stable performance.

[0007] In view of the above-mentioned defects, the inventors of the present invention finally obtained the present invention after a long period of research and practice. Summary of the invention

[0008] The purpose of the present invention is to solve the problem of mosquito repellents' dependence on organic solvents and surfactants, the problem of recycling and reusing the remaining composition after the use of DEET, and the problem that the water-based DEET composition is colorless, odorless, easy to evaporate and lose water, and breed bacteria. A colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition, a preparation method and its application are provided.

[0009] In order to achieve the above object, the present invention discloses a method for preparing a colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition, comprising the following steps:

[0010] S1, mixing agar and water, heating and stirring to obtain an agar dispersion;

[0011] S2, mixing the agar dispersion obtained in step S1 with lithium chloride, DEET and essential oil to obtain a DEET composition dispersion;

[0012] S3, placing the composition in step S2 in an ultrasonic cell crusher for ultrasonic crushing, or using a homogenizer for emulsification and mixing, and then placing the composition in a refrigerator for refrigeration to obtain a self-hygroscopic hydrogel type DEET composition;

[0013] S4, adding food coloring to the composition in step S2, ultrasonically treating the composition with a cell crusher, or emulsifying and mixing with a homogenizer, and then refrigerating the composition in a refrigerator to obtain a colored self-hygroscopic hydrogel type DEET composition.

[0014] In step S1, the mass ratio of agar to water is 1:20 to 1:100, the solution heating temperature is 90 to 95° C., and the stirring time is 0.5 to 1 h.

[0015] In step S2, the mass ratio of lithium chloride to the composition is 1:20 to 1:50.

[0016] In the step S2, the mass ratio of DEET to the composition is 1:5 to 1:100.

[0017] The ultrasonic cell pulverization time in step S3 is 0.5 to 5 minutes.

[0018] The refrigeration temperature in step S3 is 5-30°C.

[0019] The refrigeration time in step S3 is 10 to 30 minutes.

[0020] The edible pigments in step S4 include natural beta-carotene, beetroot red, curcumin, safflower yellow, lac red, bilberry red, capsicum red, capsicum orange, red rice red, chrysanthemum yellow extract, black bean red, sorghum red, corn yellow, radish red, amaranth, amaranth aluminum lake, carmine, carmine aluminum lake, erythrosine, and erythrosine aluminum lake.

[0021] The present invention also discloses a colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition prepared by the preparation method and the application of the colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition in mosquito repellent. The hydrogel system automatically absorbs water from the surrounding air to maintain a moist state. The agar remaining in the composition after the DEET preparation is used can be naturally degraded, and the used lithium chloride can be recycled and reused.

[0022] Compared with the prior art, the invention has the following beneficial effects: the invention provides a simple and easy-to-operate colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition and a preparation method thereof, wherein the method utilizes a cell crusher or an emulsifier to uniformly mix DEET, agar, lithium chloride, essential oils (citronella, holly, eucalyptus) and an edible pigment composition; utilizes the hydrogel characteristics of agar to lock DEET molecules; utilizes the water absorption characteristics of lithium chloride to maintain the moist state of the hydrogel and inhibit bacterial growth; utilizes the essential oils (citronella, holly, eucalyptus) to provide a variety of aromatic DEET hydrogel compositions for selection; utilizes the color of edible pigments to obtain a variety of colors of hydrogel-type DEET compositions, and has a good guiding significance for the simple preparation, stable storage, safe use and recyclability of DEET preparations. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1The relationship between the water loss weight change rate of the hydrogel composition with different mass fractions of lithium chloride and time. The water loss environment conditions in this study are 50°C and 50% humidity;

[0024] Figure 2 The relationship between the moisture absorption weight change rate of the hydrogel composition with different mass fractions of lithium chloride after being baked at 80℃ for 12h and the time. The moisture absorption environment conditions in this study are 50℃ and 50% humidity;

[0025] Figure 3 An optical image of a multi-color aromatic long-lasting moisturizing mosquito repellent hydrogel composition;

[0026] Figure 4 This is an optical image of the mosquito repellent gel mosquito repellent effect test test;

[0027] Figure 5 Optical images of the hydrogel composition after being left open in a real environment for 1 day and 4 months. DETAILED DESCRIPTION

[0028] The above and other technical features and advantages of the present invention are described in more detail below in conjunction with the accompanying drawings.

[0029] Example 1

[0030] (1) Preparation of agar dispersion

[0031] Mix 1g of commercial agar with 100g of water, heat to 90°C in a water bath, and stir for 30min to obtain a uniformly dispersed agar aqueous dispersion;

[0032] (2) Preparation of DEET composition dispersion

[0033] The agar dispersion obtained in step (1) is mixed with lithium chloride, 5 g of DEET and 0.1 g of wintergreen essential oil to obtain a DEET composition dispersion, wherein the content of lithium chloride is 0%, 2%, 5%, 10% and 15% respectively;

[0034] (3) Preparation of colored self-hygroscopic hydrogel type DEET composition

[0035] 10 ppm of food-grade pigment was mixed with the composition in step (2) and stirred for 10 minutes. The composition was ultrasonically treated with a cell crusher for 2 minutes to obtain a uniformly dispersed composition. The composition was placed in a refrigerator at 5°C for 10 minutes to obtain a colorful self-hygroscopic hydrogel-type DEET composition. The water loss weight change rate of the hydrogel composition with different lithium chloride contents baked at 80°C for 12 hours is as follows: Figure 1The results of this example show that the content of lithium chloride affects the water loss limit of the hydrogel composition differently, wherein the water loss limit of the lithium chloride content of 15% is less than 50%, while the water loss limit of the lithium chloride content of 0 is greater than 95%. The above results show that the content of lithium chloride plays an important role in maintaining a stable wet state of the hydrogel composition, which is conducive to the stable volatilization of the active ingredients.

[0036] Example 2

[0037] (1) Mix 1 g of commercial agar with 100 g of water, heat in a water bath to 90° C., and stir for 30 min to obtain a uniformly dispersed agar aqueous dispersion;

[0038] (2) Preparation of DEET composition dispersion

[0039] The agar dispersion obtained in step (1) is mixed with lithium chloride, 5 g of DEET and 0.1 g of wintergreen essential oil to obtain a DEET composition dispersion, wherein the content of lithium chloride is 0%, 2%, 5%, 10% and 15% respectively;

[0040] (3) Preparation of colored self-hygroscopic hydrogel type DEET composition

[0041] 10 ppm of food-grade pigment was mixed with the composition in step (2) and stirred for 10 minutes. The composition was ultrasonically treated with a cell crusher for 2 minutes to obtain a uniformly dispersed composition. The composition was placed in a refrigerator at 5°C for 10 minutes to obtain a colorful self-hygroscopic hydrogel-type DEET composition. The experimental results are as follows: Figure 2 As shown by Figure 2 It can be seen that the content of lithium chloride affects the recovery ability of the hydrogel composition after water loss, wherein the recovery ability of the lithium chloride content of 15% is 300%, while the recovery ability of the lithium chloride content of 0 is less than 110%. The above results show that the content of lithium chloride plays an important role in maintaining a stable wet state of the hydrogel composition, which is conducive to the stable volatilization of the active ingredients.

[0042] Example 3

[0043] (1) Preparation of agar dispersion

[0044] Mix 1g of commercial agar with 100g of water, heat to 90°C in a water bath, and stir for 30min to obtain a uniformly dispersed agar aqueous dispersion;

[0045] (2) Preparation of DEET composition dispersion

[0046] The agar dispersion obtained in step (1) is mixed with 1 g of lithium chloride, 5 g of DEET and 0.05 g of eucalyptus essential oil to obtain a DEET composition dispersion;

[0047] (3) Preparation of colored self-hygroscopic hydrogel type DEET composition

[0048] 10 ppm of food-grade pigment was mixed with the composition in step (2) and stirred for 10 minutes. The composition was ultrasonically treated with a cell crusher for 2 minutes to obtain a uniformly dispersed composition. The composition was placed in a refrigerator at 5°C for 10 minutes to obtain a colorful self-hygroscopic hydrogel-type DEET composition. The experimental results are as follows: Figure 3 As shown by Figure 3 It can be seen that the self-hygroscopic hydrogel-type DEET composition prepared in this embodiment can be customized as needed, and the pigment used is food grade to meet the user's preference for different colors.

[0049] Example 4

[0050] (1) Preparation of agar dispersion

[0051] Mix 1g of commercial agar with 100g of water, heat to 90°C in a water bath, and stir for 30min to obtain a uniformly dispersed agar aqueous dispersion;

[0052] (2) Preparation of DEET composition dispersion

[0053] The agar dispersion obtained in step (1) is mixed with 1 g of lithium chloride, 5 g of DEET and 0.01 g of wintergreen essential oil to obtain a DEET composition dispersion;

[0054] (3) Preparation of colored self-hygroscopic hydrogel type DEET composition

[0055] 10 ppm of food grade pigment was mixed with the composition in (2) and stirred for 10 minutes, and the composition was ultrasonically treated with a cell crusher for 2 minutes to obtain a uniformly dispersed composition, which was placed in a refrigerator at 5°C for 10 minutes to obtain a white self-hygroscopic hydrogel type DEET composition. The experimental results are as follows: Figure 4 As shown by Figure 4 It can be seen that the self-hygroscopic hydrogel-type DEET composition prepared in this embodiment can kill mosquitoes quickly and efficiently.

[0056] Example 5

[0057] (1) Preparation of agar dispersion

[0058] Mix 1g of commercial agar with 100g of water, heat to 90°C in a water bath, and stir for 30min to obtain a uniformly dispersed agar aqueous dispersion;

[0059] (2) Preparation of DEET composition dispersion

[0060] The agar dispersion obtained in step (1) is mixed with 1 g of lithium chloride, 5 g of DEET and 0.1 g of wintergreen essential oil to obtain a DEET composition dispersion;

[0061] (3) Preparation of colored self-hygroscopic hydrogel type DEET composition

[0062] 10 ppm of food grade pigment was mixed with the composition in (2) and stirred for 10 minutes, and the composition was ultrasonically treated with a cell crusher for 2 minutes to obtain a uniformly dispersed composition, which was placed in a refrigerator at 5°C for 10 minutes to obtain a colorful self-hygroscopic hydrogel type DEET composition. The experimental results are as follows: Figure 5 As shown by Figure 5 It can be seen that the appearance of the self-hygroscopic hydrogel-type DEET composition prepared in this example changes after being placed in a room temperature environment for 4 consecutive months, indicating that the DEET composition of the present invention can maintain its basic shape for a long time.

[0063] Example 6

[0064] First, prepare natural containers in advance to breed mosquitoes. When the density of mosquitoes is high, in the evening, use the electric mosquito suction device to capture the natural and healthy blood-sucking female mosquitoes by human luring and put them in the mosquito trap for later use. Secondly, use a knife to cut a mosquito repellent gel with a thickness of 0.5 mm, stick it on the attractant placement paper of the attractant bottle, and use a knife to trim the shape of the gel sheet to the same size as the attractant sheet, trim it into a gel volatile sheet with a diameter of 4 cm and a thickness of 0.5 mm, and connect it to the closed plastic film with its own connecting rod for later use. Thirdly, use an electric mosquito suction device to randomly suck a certain number of mosquitoes into the attractant bottle, and quickly cover the prepared plastic film with the mosquito repellent gel sheet on the bottle mouth and tighten it with a rubber band. Finally, make a mark and record the knockdown of mosquitoes at different time points and the fumigation effect at the last time point. The standard for mosquito knockdown is that the mosquito body turns over and cannot resume flying after shaking the attractant bottle. The standard for mosquito death is that the mosquito is completely dead and there is no movement when shaking the attractant bottle. The experimental results are shown in Table 1. This example compares the performance of various DEET compositions in killing mosquitoes, wherein the higher the DEET content, the better the effective fumigation effect, and the fumigation performance of the combination of DEET and essential oil is even better.

[0065] Table 1 Comparison of the performance of DEET compositions in fumigating mosquitoes

[0066]

[0067]

[0068] The above description is only a preferred embodiment of the present invention, which is only illustrative and not restrictive of the present invention. Those skilled in the art understand that many changes, modifications, and even equivalences may be made to the present invention within the spirit and scope defined by the claims of the present invention, but all of them will fall within the scope of protection of the present invention.

Claims

1. A method for preparing a colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition, characterized in that: It consists of the following steps: S1, mixing agar and water, heating and stirring to obtain an agar dispersion; S2, mixing the agar dispersion obtained in step S1 with lithium chloride, DEET and essential oil to obtain a DEET composition dispersion; S3, adding food coloring to the composition in step S2, ultrasonically treating the composition with a cell crusher, or emulsifying and mixing the composition with a homogenizer, and then refrigerating the composition in a refrigerator to obtain a colored self-hygroscopic hydrogel type DEET composition; In step S2, the essential oil is citronella essential oil, wintergreen essential oil or eucalyptus essential oil, and the mass percentages of DEET, essential oil and lithium chloride are 7% DEET, 1% essential oil and 2% lithium chloride respectively.

2. The method for preparing a colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition according to claim 1, characterized in that: The ultrasonic cell pulverization time in step S3 is 0.5 to 5 minutes.

3. The method for preparing a colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition according to claim 1, characterized in that: The refrigeration temperature in step S3 is 5-30°C.

4. The method for preparing a colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition according to claim 1, characterized in that: The refrigeration time in step S3 is 10 to 30 minutes.

5. The method for preparing a colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition according to claim 1, characterized in that: The edible pigments in step S3 include natural beta-carotene, beetroot red, curcumin, safflower yellow, lac red, bilberry red, capsicum red, capsicum orange, red rice red, chrysanthemum yellow extract, black bean red, sorghum red, corn yellow, radish red, amaranth, amaranth aluminum lake, carmine, carmine aluminum lake, erythrosine, and erythrosine aluminum lake.

6. A colorful, aromatic, long-lasting, moisturizing and mosquito-repellent hydrogel composition prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the colorful aromatic long-lasting moisturizing mosquito repellent hydrogel composition as claimed in claim 6 in repelling mosquitoes.

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