Efficient maidenhair mosquito-repellent green essential oil and preparation method thereof

Abstract

The invention relates to the technical field of mosquito-repelling essential oil, in particular to high-efficiency French marigold mosquito-repelling green essential oil which is prepared from the following raw materials: French marigold essential oil, auxiliary plant essential oil, a green nonionic surfactant, food-grade ethanol and deionized water. The auxiliary plant essential oil is selected from at least one of lemongrass essential oil, peppermint essential oil, lavender essential oil, citronella essential oil, chamomile essential oil, rosemary essential oil and folium eucalypti essential oil; the green non-ionic surface active agent is selected from at least one of Tween 80, polyglycerol fatty acid ester, coco-glucoside and polyglyceryl-3 laurate. According to the invention, the Indian maidenhair essential oil is taken as the core, the unique mosquito-repelling activity of the Indian maidenhair essential oil provides core support for the efficient mosquito-repelling performance of the product, and compared with the existing product with a single component or non-Indian maidenhair as the core, the mosquito-repelling efficiency is greatly improved, and the core function advantage of the product is guaranteed from the source.

Description

Technical Field

[0001] This invention relates to the field of mosquito repellent essential oil technology, specifically to a highly effective green mosquito repellent essential oil made from Inca marigold and its preparation method. Background Technology

[0002] With increasing awareness of health and environmental protection, green mosquito repellent products are gradually becoming the mainstream in the market, with plant essential oil mosquito repellent products being particularly popular due to their natural and gentle properties. However, existing mosquito repellent essential oil technology still has many problems that urgently need to be solved. Some products rely on a single plant essential oil as the core ingredient, resulting in limited mosquito repellent effects and short-lived effects, making it difficult to meet actual usage needs. Other products use simple compounding methods to mix multiple essential oils, but fail to form an effective synergistic system; some components even exhibit antagonistic effects, which not only affect mosquito repellent efficiency but may also result in a pungent odor and a poor user experience.

[0003] In terms of stability, existing essential oil products generally suffer from problems such as easy layering, sedimentation, and oxidative deterioration, resulting in a short shelf life at room temperature, which limits product storage and use. Regarding additives, many products still use traditional, non-green additives, which, while improving dispersibility to some extent, pose a risk of skin irritation and do not align with the trend towards safety and environmental protection. At the manufacturing process level, traditional extraction methods result in low extraction rates and purity, leading to easy loss of active ingredients; the compounding process lacks precise parameter control, resulting in insufficient component integration; and simplified post-processing makes it difficult to guarantee product purity and stability.

[0004] Furthermore, existing products have limitations in their compatibility. Some have weak broad-spectrum repellency, targeting only mosquitoes and failing to address a variety of harmful organisms such as mites and bedbugs; others lack sufficient safety, failing to meet the needs of infants, young children, and those with sensitive skin. Additionally, there are few products specifically designed for different scenarios such as home use, outdoor activities, and camping, making it difficult to comprehensively cover diverse usage needs. These technical deficiencies prevent existing mosquito repellent essential oil products from achieving a balance of high efficiency, long-lasting effects, safety, and stability, thus hindering the development and application of green mosquito repellent essential oil technology. Summary of the Invention

[0005] The primary objective of this invention is to provide a highly effective green essential oil for mosquito repelling from Inca marigolds and its preparation method.

[0006] A further objective of this invention is to provide a mosquito-repellent green essential oil, composed of the following ingredients: Inca marigold essential oil, auxiliary plant essential oils, a green nonionic surfactant, food-grade ethanol, and deionized water; wherein the auxiliary plant essential oils are selected from at least one of lemongrass essential oil, peppermint essential oil, lavender essential oil, citronella essential oil, chamomile essential oil, rosemary essential oil, and eucalyptus essential oil; and wherein the green nonionic surfactant is selected from at least one of Tween 80, polyglycerol fatty acid esters, cocoyl glucoside, and polyglycerol-3-laurate.

[0007] Preferably, the mass percentage range of each raw material is as follows: 10 to 30 parts of Inca marigold essential oil, 2 to 14 parts of auxiliary plant essential oil, 2 to 7 parts of green nonionic surfactant, 42 to 68 parts of food-grade ethanol, and 9 to 31 parts of deionized water.

[0008] Preferably, the raw materials also include natural antioxidants, which are selected from at least one of vitamin E and vitamin C, and are present in a mass percentage of 1 part.

[0009] Preferably, the raw materials also include menthol, which is 1 part by mass.

[0010] A method for preparing the aforementioned mosquito-repellent green essential oil includes the following steps: (1) Extraction of Inca Marigold essential oil: Select fresh whole plant of Inca Marigold, remove rotten parts, wash and dry, then crush, add food grade ethanol, extract by ultrasonication, let stand and filter, and distill the filtrate under reduced pressure to recover ethanol to obtain crude essential oil. The crude essential oil is purified by silica gel column chromatography to obtain Inca Marigold essential oil. (2) Blending of compound essential oils: Add the Inca Marigold essential oil and the auxiliary plant essential oils to the reaction vessel according to the ratio, and stir to obtain the compound essential oil; (3) Stabilization treatment: Add green nonionic surfactant to the mixed essential oils, stir, and then add a mixture of food-grade ethanol and deionized water dropwise. Heat and keep warm while stirring to obtain a uniform essential oil system. (4) Post-processing: Filter the essential oil system, seal and let it stand in the dark to obtain mosquito repellent green essential oil.

[0011] Preferably, in step (1), the particle size of the crushed Cotyledon Inca is 40 to 60 mesh, the amount of food-grade ethanol added is 5 times the mass of Cotyledon Inca, the temperature of ultrasonic extraction is 35°C, the ultrasonic power is 150 to 180W, and the extraction time is 30 to 45 minutes; the eluent for silica gel column chromatography is a mixture of petroleum ether and ethanol.

[0012] Preferably, in step (2), the stirring temperature is 22 to 30°C, the stirring speed is 250 to 400 revolutions per minute, and the stirring time is 15 to 25 minutes; ultrasonic-assisted dispersion can be performed during the stirring process.

[0013] Preferably, in step (3), the stirring time after adding the green nonionic surfactant is 20 to 30 minutes; after the ethanol and deionized water mixture is added dropwise, the temperature is raised to 30 to 40°C and the stirring time is 30 to 50 minutes.

[0014] Preferably, in step (4), the filtration is precision filtration, the filter membrane material is polyvinylidene fluoride; the standing temperature is 20 to 25°C, and the standing time is 12 to 36 hours.

[0015] Preferably, in step (4), the filtration process may include an ultraviolet sterilization step; in step (1), the purity of the food-grade ethanol is 75% or 95%.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses Inca marigold essential oil as its core ingredient. Its unique mosquito-repelling activity provides the core support for the product's high-efficiency mosquito-repelling performance. Compared with existing products with single ingredients or non-Inca marigold as the core ingredient, it greatly improves the mosquito-repelling efficiency and ensures the core functional advantages of the product from the source.

[0017] 2. This invention precisely selects auxiliary ingredients such as lemongrass essential oil and lavender essential oil and optimizes their ratio. Combined with process optimization, it promotes the full integration of the molecules of each component, forming a synergistic compound system. This not only enhances the mosquito repellent effect but also improves the product's odor, overcoming the limitations of existing compound essential oils with poor synergy and pungent odor.

[0018] 3. This invention replaces traditional irritating additives and selects mild and environmentally friendly nonionic surfactants and natural antioxidants. While improving product stability and skin adhesion, it significantly reduces skin irritation, achieving the green and safe attributes of the product and making it suitable for a wider range of users.

[0019] 4. This invention forms an organic whole from extraction, compounding, stabilization to post-processing, effectively improving the extraction rate and purity of the core essential oils, fully preserving active ingredients, avoiding ingredient loss and antagonism, while improving the stability of the product system, extending the shelf life, and ensuring that the product can maintain excellent performance under different environments.

[0020] 5. The product series design of this invention covers four types: basic, long-lasting, safe, and broad-spectrum. It can not only meet the daily mosquito repellent needs of ordinary users, but also be suitable for special groups such as infants and young children and those with sensitive skin. It can also cope with diverse scenarios such as home, outdoor, and camping. At the same time, it has the ability to repel a variety of mosquitoes such as mites and bed bugs, which significantly expands the application range of the product. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0022] Raw material composition by mass percentage: The formula contains 15% Inca marigold essential oil, 3% lemongrass essential oil, 2% peppermint essential oil, 2% Tween 80, 68% food-grade ethanol, and 10% deionized water. Among them, Tween 80 is a green nonionic surfactant, the food-grade ethanol has a purity of 95%, and the resistivity of deionized water is ≥18.2 MΩ·cm.

[0023] Preparation method: (1) Extraction of Inca Marigold essential oil: Fresh whole plant of Inca Marigold was selected, rotten parts were removed, washed and dried, and then pulverized to 40-60 mesh. Food-grade ethanol was added in 5 times its weight, and ultrasonic extraction was carried out at 35℃ and ultrasonic power of 150W for 30 min. Then it was allowed to stand for 2 h and filtered to remove the residue. The filtrate was distilled under reduced pressure at 45℃ and vacuum degree of -0.08MPa to recover the ethanol and obtain crude Inca Marigold essential oil. The crude essential oil was purified by silica gel column chromatography with petroleum ether-ethanol mixture as eluent at a volume ratio of 8:2. The eluent was collected and distilled under reduced pressure to obtain Inca Marigold essential oil with a purity ≥95%. This extraction process solves the problems of low extraction rate and insufficient purity of existing single solvent extraction processes. Compared with the existing traditional soaking extraction process, the extraction rate is increased by more than 20% and the purity is increased by more than 15%. The ultrasonic equipment used in the extraction process was a conventional laboratory ultrasonic instrument with an adjustable power range of 50-200W; the vacuum distillation equipment was a rotary evaporator with an adjustable vacuum range of -0.05 to -0.1MPa.

[0024] (2) Blending of compound essential oils: According to the above ratio, add Inca Indica patula essential oil, lemongrass essential oil, and peppermint essential oil to a 500mL reactor. Stir for 15 minutes at 25℃ and a stirring speed of 300r / min to obtain a mixed essential oil. This initially achieves synergy between the core and auxiliary components, overcoming the limitation of the limited mosquito-repellent effect of a single Inca Indica patula essential oil. Unlike existing simple compounding schemes, this step promotes the fusion of component molecules and avoids component antagonism by precisely controlling the stirring parameters. The stirring paddle of the reactor has an anchor-type structure with an adjustable speed range of 0-500r / min, which can achieve uniform stirring.

[0025] (3) Stabilization treatment: Slowly add Tween 80 to the mixed essential oils, maintaining a constant stirring speed and stirring for 20 minutes. Then, add a mixture of ethanol and deionized water dropwise at a volume ratio of 6.8:1. After the addition is complete, raise the temperature to 30°C and maintain the temperature while stirring for 30 minutes to obtain a homogeneous essential oil system. This step solves the problems of easy stratification and poor stability of existing essential oils. Compared with existing stabilization processes, the shelf life of the product at room temperature is extended by more than 6 months. The heating process uses a water bath heating method with a temperature control accuracy of ±1°C to ensure process stability.

[0026] (4) Post-processing: The above essential oil system is precision filtered using a 0.22μm pore size filter made of polyvinylidene fluoride. After removing impurities, it is left to stand for 12 hours under light-proof and sealed conditions to obtain the basic high-efficiency Inca Marigold mosquito repellent green essential oil. This product can achieve a mosquito repellency rate of ≥90% and a duration of effectiveness of ≥4 hours. Its basic performance is significantly better than existing single-component mosquito repellent essential oils and simple compound mosquito repellent essential oils. The mosquito repellency rate is increased by more than 10% compared with existing single-component essential oils, and the duration of effectiveness is extended by more than 1.5 hours. The filtration equipment is a vacuum filtration device, and the filtration pressure is controlled at 0.02-0.05MPa to avoid excessive pressure from damaging the active ingredients of the essential oil. Example

[0027] Based on the formulation and process of Example 1, this embodiment optimizes the components and ratio of the compound essential oils, upgrades the stabilization process, and introduces dual green additives and natural antioxidants to achieve a dual improvement in efficacy and odor compatibility, while avoiding the defects of existing technical combination solutions.

[0028] Raw material composition by mass percentage: The formula contains 22% Inca Marigold essential oil, 4% lemongrass essential oil, 3% lavender essential oil, 2% citronella essential oil, 3% Tween 80, 2% polyglycerol fatty acid ester, 55% food-grade ethanol, 9% deionized water, and 1% vitamin E. The polyglycerol fatty acid ester is a green nonionic surfactant, primarily used to enhance adhesion; vitamin E is a natural antioxidant with a purity ≥98%; and the food-grade ethanol has a purity of 95%.

[0029] Preparation method: (1) Extraction of Inca Marigold essential oil: The extraction process of Example 1 was followed, but the ultrasonic extraction time was optimized to 40 min, and the volume ratio of silica gel column chromatography eluent was adjusted to 7:3, further improving the purity of Inca Marigold essential oil to ≥96%, enhancing the activity of the core mosquito-repellent components, and solving the problem of insufficient activity of the core components in Example 1, which resulted in a short duration of effect. Compared with Example 1, the activity of the core components was increased by more than 10%. At the same time, unlike the existing extraction process, this step achieved simultaneous improvement of purity and activity through parameter optimization, avoiding the problem of activity loss caused by purity improvement in the existing process.

[0030] (2) Compound essential oil blending: In accordance with the specified ratio, cosmos stigma essential oil, lemongrass essential oil, lavender essential oil, and lemongrass essential oil were added to a 500mL reaction vessel. The mixture was stirred for 20 minutes at 28℃ and a stirring speed of 350r / min. During this period, ultrasonic-assisted dispersion was performed every 5 minutes (100W for 30s) to promote the full fusion of different essential oil molecules, enhance the synergistic mosquito-repelling effect, and improve the product's aroma by adding lavender essential oil, thus solving the problem of a single aroma in Example 1 and overcoming the limitations of poor synergy and pungent odor in existing compound essential oil blends. Compared to existing simple compounding processes, the component fusion degree is improved by more than 30%, and the synergistic mosquito-repelling effect is improved by more than 15%.

[0031] (3) Stabilization treatment: First, Tween 80 and polyglycerol fatty acid esters are mixed evenly at a ratio of 3:2, added to the reaction vessel and mixed with the compound essential oil, and stirred for 25 min. Then, vitamin E is added and stirred for another 10 min. Next, a mixture of ethanol and deionized water is added dropwise at a volume ratio of 55:9. After the addition is complete, the temperature is raised to 35°C and kept warm while stirring for 40 min. At the same time, intermittent ultrasound is used with a power of 120W, each time for 30 s, with an interval of 5 min, to improve the stability of the system and the compatibility of the components. The addition of polyglycerol fatty acid esters can enhance the adhesion of the essential oil to the skin surface, and vitamin E can delay the oxidation of the essential oil, providing double protection for the duration of efficacy and solving the problems of insufficient duration of efficacy and easy oxidation and deterioration in Example 1. Compared with the existing stabilization process and technology combination scheme, the product's duration of efficacy is extended by more than 60%, and the oxidation stability is improved by more than 40%.

[0032] (4) Post-processing: Using the precision filtration process of Example 1, the filtered oil is left to stand for 24 hours at 25°C, in the dark and sealed environment to allow the essential oil system to fully stabilize, thus obtaining a long-lasting, high-efficiency Inca Marigold mosquito repellent green essential oil. This product has a mosquito repellency rate of ≥95%, a duration of effectiveness of ≥7 hours, a mild scent, and significantly better stability than Example 1, existing compound mosquito repellent essential oils, and existing technical combination schemes. The duration of effectiveness is extended by more than 45% compared to existing technical combination schemes. Example

[0033] Based on the formulation and process of Example 2, this embodiment optimizes the adjuvant system, replaces it with mild and green adjuvants, adjusts the raw material ratio, reduces the solvent concentration, and improves biosafety, while retaining the high-efficiency mosquito repellent performance, achieving a balance between safety and high efficiency, adapting to the needs of special populations, and breaking through the limitations of existing technologies and combination solutions.

[0034] Raw material composition by mass percentage: This formula contains 10% Inca Marigold essential oil, 2% lemongrass essential oil, 3% lavender essential oil, 2% chamomile essential oil, 4% cocoyl glucoside, 2% polyglycerol-3-laurate, 45% low-concentration food-grade ethanol, 31% deionized water, and 1% vitamin C. Cocoyl glucoside is a green nonionic surfactant, gentle and non-irritating; polyglycerol-3-laurate is a mild emulsifier; low-concentration food-grade ethanol has a purity of 75%; and vitamin C is a natural antioxidant with a purity ≥99%.

[0035] Preparation method: (1) Extraction of Inca Marigold essential oil: The extraction process of Example 2 was followed, but the concentration of the extraction solvent ethanol was reduced from 95% to 75%. This reduced the impact of the solvent on the active ingredients of the essential oil during the extraction process and reduced the risk of subsequent residues. The purity of the purified essential oil was ≥95%, ensuring the safety and efficiency of the core components and solving the irritation problem that may have been caused by solvent residues in Example 2. Compared with the existing extraction process and technology combination scheme, the amount of solvent residue was reduced by more than 80%, and the irritation was significantly reduced.

[0036] (2) Compound essential oil blending: Add Inca Marigold essential oil, lemongrass essential oil, lavender essential oil, and chamomile essential oil to a 500mL reactor according to the specified ratio. Stir slowly for 25 minutes at 22℃ and a stirring speed of 250r / min to avoid damaging the active ingredients in the essential oils due to high temperature and high-speed stirring. At the same time, the addition of chamomile essential oil neutralizes some of the irritation of the essential oils, improving the product's mildness and solving the problem of unsuitability for special populations caused by irritation in Example 2. This overcomes the limitation of insufficient mosquito repellent effect of existing mosquito repellent essential oils for special populations. Compared with existing essential oil and technology combination solutions for special populations, the mosquito repellent effect is improved by more than 20%, and the irritation is reduced to a non-irritating level.

[0037] (3) Stabilization treatment: First, mix cocoyl glucoside and polyglycerol-3 laurate evenly, add them to the reaction vessel and mix with the compound essential oil, stir for 30 min, add vitamin C and continue stirring for 15 min, then add a mixture of low concentration ethanol and deionized water dropwise at a volume ratio of 45:31, with the dropping rate controlled at 1-2 drops / second. After the addition is complete, keep the mixture at 30℃ and stirring at a stirring speed of 200 r / min for 50 min to ensure that the system is mild and stable and that no irritating substances are generated. Cocoyl glucoside partially replaces Tween 80, further reducing irritation, while vitamin C combines antioxidant and mild properties, making it suitable for the needs of special populations. Compared with existing adjuvant systems and technical combinations, the product's mildness is improved by more than 50%, while maintaining good stability.

[0038] (4) Post-processing: A dual filtration process is adopted, first filtering through a 0.45μm filter membrane, and then through a 0.22μm filter membrane. Both filter membranes are made of polyvinylidene fluoride to remove minute impurities. After filtration, the product is left to stand at 20℃, protected from light, and sealed for 36 hours to further improve product stability and safety, thus obtaining a safe and highly effective Inca Marigold mosquito repellent green essential oil. This product has a mosquito repellency rate of ≥91%, an effective duration of ≥5 hours, and no skin irritation. It is suitable for infants, young children, and people with sensitive skin, effectively solving the problem of balancing the effectiveness and safety of existing mosquito repellent essential oils for special populations. Compared with existing essential oil and technology combination solutions for special populations, it achieves a dual improvement in mosquito repellency and gentleness. Example

[0039] This embodiment integrates the core technologies of the previous three examples, further expands the range of raw material ratios, increases active ingredients targeting various mosquitoes, optimizes the process to adapt to complex scenarios, achieves a breakthrough in broad-spectrum repellency and multi-scenario adaptability, and avoids the component antagonism problem of existing technology combination schemes.

[0040] Raw material composition by mass percentage: The formula contains 30% Inca Marigold essential oil, 5% lemongrass essential oil, 3% citronella essential oil, 2% rosemary essential oil, 1% eucalyptus essential oil, 2% Tween 80, 3% polyglycerol fatty acid ester, 42% food-grade ethanol, 10% deionized water, 1% vitamin E, and 1% menthol. Menthol primarily enhances the cooling sensation and provides broad-spectrum mosquito repellency; the food-grade ethanol has a purity of 95%; and the vitamin E has a purity of ≥98%.

[0041] Preparation method: (1) Extraction of Inca Marigold essential oil: The extraction process of Example 2 was used, but the ultrasonic extraction power was increased to 180W and the extraction time was extended to 45min to further improve the extraction rate of the core mosquito-repellent components. The volume ratio of silica gel column chromatography eluent was adjusted to 6:4 to ensure that the purity of the essential oil was ≥97% and to enhance the broad-spectrum mosquito-repellent activity. This step integrates the advantages of the extraction process of Examples 1-2 to improve the efficacy of the core components. Compared with the existing extraction process and technology combination scheme, the extraction rate of the core components is increased by more than 25%, and the broad-spectrum mosquito-repellent activity is increased by more than 30%.

[0042] (2) Compound essential oil blending: In accordance with the specified ratio, cosmos stigma essential oil, lemongrass essential oil, citronella essential oil, rosemary essential oil, and eucalyptus essential oil were added to a 500mL reaction vessel. The mixture was stirred for 20 minutes at 30℃ and a stirring speed of 400r / min, while continuous ultrasonic dispersion was performed at 150W for 1 minute with 3-minute intervals to promote the synergistic effect of the various essential oil active ingredients and avoid component antagonism. The addition of rosemary and eucalyptus essential oils enhances the repellency against mites, bedbugs, and other mosquitoes, overcoming the limitation of Examples 1-3 which only target mosquitoes, and solving the problem of insufficient broad-spectrum efficacy of existing essential oils. Compared to existing broad-spectrum mosquito repellent essential oils and technical combinations, the risk of component antagonism is reduced by more than 90%, and the repellency rate against various mosquitoes is increased by more than 25%.

[0043] (3) Stabilization treatment: First, Tween 80 and polyglycerol fatty acid esters are mixed evenly and added to the reaction vessel to mix with the compound essential oil. Stir for 25 minutes, then add vitamin E and menthol and continue stirring for 15 minutes. Add a mixture of ethanol and deionized water dropwise at a volume ratio of 42:10. After the addition is complete, raise the temperature to 40°C and keep stirring for 45 minutes to improve the stability of the system under complex environments such as high temperature and humidity. This step integrates the long-lasting adjuvant system of Example 2 with the mild process logic of Example 3, taking into account both long-lasting effect, stability and mildness. Compared with the existing stabilization process and technology combination scheme, the stability of the product under complex environments is improved by more than 40%, and the duration of effect is maintained at more than 6.5 hours.

[0044] (4) Post-treatment: Precision filtration and ultraviolet sterilization are adopted. After filtration, the UV light intensity is 200μW / cm. 2 Sterilize for 15 minutes under the specified conditions using a standard desktop UV sterilizer to avoid residual bacteria. After sterilization, let it stand for 24 hours at 25℃ in a dark, sealed environment to obtain a broad-spectrum, highly effective Inca Marigold mosquito repellent essential oil. This product has a mosquito repellency rate of ≥97% and a duration of effectiveness of ≥6.5 hours. It is highly effective against various mosquitoes, including mites and bedbugs, and is suitable for diverse scenarios such as home use, outdoor activities, and camping. It completely breaks through the limitations of existing essential oil application scenarios and significantly expands the application scenarios compared to existing technologies and technology combinations. Example

[0045] Raw material composition: by mass percentage: The formula contains 28% Inca Marigold essential oil, 4% lemongrass essential oil, 3% citronella essential oil, 3% rosemary essential oil, 2% eucalyptus essential oil, 1% Tween 80, 4% polyglycerol fatty acid ester, 40% food-grade ethanol, 13% deionized water, 1% vitamin E, 1% menthol, and 0.5% sodium hyaluronate. The optimized ratio of polyglycerol fatty acid ester to Tween 80 enhances emulsification stability at high temperatures, while sodium hyaluronate acts as a natural moisturizing and adhesion enhancer, improving the adhesion of the essential oils to sweaty skin. The food-grade ethanol has a purity of 95%, and the sodium hyaluronate has a purity of ≥99%.

[0046] Preparation method: (1) Extraction of Inca Marigold essential oil: The extraction process of Example 4 was followed, and the volume ratio of silica gel column chromatography eluent was adjusted to 5:5 to further improve the retention rate of high temperature resistant active ingredients in the core essential oil. The purity of the purified essential oil was ≥97.5%.

[0047] (2) Blending of compound essential oils: Add Inca Marigold essential oil, lemongrass essential oil, citronella essential oil, rosemary essential oil, and eucalyptus essential oil to a 500mL reactor according to the specified ratio. Stir at 32℃ and a stirring speed of 450r / min for 22min, with continuous ultrasonic-assisted dispersion during the process (power 160W, time 90s, interval 2min). By increasing the stirring speed and adjusting the ultrasonic parameters, a more compact synergistic system of essential oil molecules is promoted, resisting molecular dissociation at high temperatures.

[0048] (3) Stabilization treatment: First, mix Tween 80 and polyglycerol fatty acid ester evenly, add them to the reaction vessel and mix with the compound essential oil for 28 min. Then, add vitamin E, menthol, and sodium hyaluronate in sequence and continue stirring for 18 min. Add a mixture of ethanol and deionized water (volume ratio 40:13) dropwise. After the addition is complete, raise the temperature to 45℃ and keep it warm while stirring for 60 min. During this period, continuous ultrasound (power 130W) is used. The combination of high temperature heat preservation and continuous ultrasound enhances the compatibility between the additives and the essential oil. The molecular film formed by sodium hyaluronate reduces the volatilization of active ingredients.

[0049] (4) Post-treatment: A triple precision filtration process is adopted (passing through 0.45μm, 0.22μm, and 0.1μm polyvinylidene fluoride filter membranes in sequence) to remove minute impurities and particles that may affect high-temperature stability; after filtration, ultraviolet sterilization is performed (intensity 220μW / cm). 2 The product is then left to stand for 18 minutes (18 minutes) and then left to stand for 28 hours at 23°C in a dark, sealed environment to obtain an outdoor extreme environment-adapted product.

[0050] Comparative Example 1: Raw material composition by mass percentage: The formula contains 6% lemongrass essential oil, 5% lavender essential oil, 4% citronella essential oil, 3% Tween 80, 2% polyglycerol fatty acid ester, 55% ethanol, 9% deionized water, and 1% vitamin E. It does not include Inca Marigold essential oil. The remaining components and proportions are consistent with Example 2. This formula replicates the existing single-essence blending technique, but does not use Inca Marigold as the core ingredient.

[0051] Preparation method: Using the preparation method of Example 2, only the extraction step of Marigold essential oil is omitted, and the compound essential oil is directly blended and the subsequent processes are carried out, thus replicating the existing compound essential oil preparation process.

[0052] Comparative Example 2: Raw material composition by mass percentage: This formula contains 30% Inca marigold essential oil, 5% Tween 80, 55% ethanol, and 10% deionized water. It contains no compound plant essential oils, and the remaining components and proportions have been adjusted accordingly. This formula replicates the existing single-plant essential oil mosquito repellent technology, relying solely on a single core ingredient.

[0053] Preparation method: Using the extraction process of Inca marigold essential oil from Example 2, only the mixing and stabilization treatment of single essential oil with auxiliaries and solvents is performed. The steps of compound essential oil blending and ultrasonic-assisted dispersion are omitted, thus replicating the existing single-component essential oil preparation process.

[0054] Comparative Example 3: Raw material composition by mass percentage: The formula contains 22% Inca Marigold essential oil, 4% lemongrass essential oil, 3% lavender essential oil, 2% citronella essential oil, 5% sodium dodecylbenzenesulfonate, 55% ethanol, 9% deionized water, and 1% vitamin E. Traditional adjuvants are used instead of the green adjuvants in Example 2, while the remaining components and proportions remain the same. This formula replicates the existing traditional adjuvant mosquito repellent essential oil technology, but does not employ a green adjuvant system.

[0055] Preparation method: The preparation method of Example 2 is used, except that the green additive is replaced with a traditional additive, while the other process steps remain unchanged, thus replicating the existing traditional additive system preparation process.

[0056] Comparative Example 4: Raw material composition by mass percentage: Completely consistent with Example 2, ensuring no difference in raw material ratios, only verifying the technical value of process optimization.

[0057] Preparation method: (1) Extraction of Inca Marigold essential oil: The ultrasonic extraction step is omitted, and only ethanol soaking extraction is used. Soaking at 35℃ for 2 hours is omitted, and the silica gel column chromatography purification step is omitted. Crude essential oil is used directly, replicating the existing simplified extraction process.

[0058] (2) Compound essential oil blending: only simple stirring is performed at 25℃, 200r / min, and 10min, without ultrasonic-assisted dispersion steps, replicating the existing simple compounding process.

[0059] (3) Stabilization treatment: All components are directly mixed and stirred for 30 minutes without heat preservation stirring and intermittent ultrasonic steps, replicating the existing simplified stabilization process.

[0060] (4) Post-treatment: only a single filtration is performed, using a 0.45μm filter membrane, without a static stabilization step, replicating the existing simplified post-treatment process.

[0061] Comparative Example 5: Raw material composition by mass percentage: It contains 20% lemongrass essential oil, 4% Tween 80, 66% ethanol, and 10% deionized water, precisely replicating a typical single-plant essential oil mosquito repellent formula in existing technologies. It does not contain the core Inca Indigo essential oil, nor any complex synergistic ingredients.

[0062] Preparation method: Lemongrass essential oil is extracted by traditional ethanol soaking at 35°C for 1 hour. After filtration, it is directly mixed with Tween 80, ethanol, and deionized water and stirred for 20 minutes. There are no purification, ultrasonic dispersion, or heat preservation stabilization steps. It accurately replicates the conventional process of existing technology without any optimization design.

[0063] Comparative Example 6: Raw material composition by mass percentage: The formula consists of 15% Inca marigold essential oil, 3% lemongrass essential oil, 2% peppermint essential oil, 3% sodium dodecylbenzenesulfonate, 67% ethanol, and 10% deionized water. It is a simple combination of existing Inca marigold essential oil technology and existing compound essential oil technology. The adjuvants are of the traditional type and no synergistic optimization has been performed.

[0064] Preparation method: Traditional soaking methods were used to extract essential oils from Inca marigold, lemongrass, and peppermint, respectively. There was no purification step; the oils were directly mixed and then mixed with traditional additives, ethanol, and deionized water. The mixture was simply stirred for 30 minutes without ultrasonic assistance or temperature stabilization optimization. This method precisely replicated the simple superposition of existing technologies without any process synergy optimization.

[0065] To comprehensively verify the mosquito-repellent effect, duration of action, stability, safety, and broad spectrum of the essential oil of this invention, and to accurately compare the performance differences of existing technologies and combinations thereof, performance tests were conducted on the products of Examples 1-4 and Comparative Examples 1-6. The test methods all comply with relevant national standards, and the specific test methods for each indicator are as follows.

[0066] (1) Method for testing mosquito repellency rate: The tests were conducted according to the national standard GB / T13917.9-2009 "Indoor Efficacy Test Methods for Sanitary Insecticides for Pesticide Registration - Part 9: Repellents". Test environment: temperature 25±2℃, relative humidity 65±5%, no airflow interference; Test mosquitoes: 3-5 days after emergence, non-biting female Culex pipiens pallens were selected, with 200 mosquitoes per group, starved for 24 hours before use; Test samples: The products of each example and comparative example were diluted to the actual usage concentration (1:10 dilution with deionized water), while the control group used deionized water; Test procedure: Ten healthy volunteers were selected (5 males and 5 females, aged 20-45 years, with no history of skin diseases or allergies). A 4cm×6cm area of ​​the inner forearm skin of the volunteers was exposed. The remaining areas were covered with opaque fabric; 0.5 mL of test sample was applied to the exposed areas, and the area was allowed to air dry for 30 minutes; the forearm after applying the sample was inserted into a mosquito breeding cage (1m×1m×1m) for 2 minutes each time, and the number of mosquitoes that landed and attempted to suck blood was recorded; the test was repeated every 1 hour until the mosquito repellency rate was less than 80%; the mosquito repellency rate was calculated as follows: mosquito repellency rate (%) = (number of mosquitoes landing in the control group - number of mosquitoes landing in the test group) / number of mosquitoes landing in the control group × 100%, and the average of the test results of 10 volunteers was taken as the final data.

[0067] (2) Duration of effect test method: Based on the above mosquito repellency testing method, the testing period was extended, and the changes in mosquito repellency of each test sample were continuously recorded. The test began after the sample was applied and allowed to dry. A mosquito repellency test was conducted every 1 hour. The test was stopped when the mosquito repellency rate was below 80% for two consecutive tests. The time interval from the first application of the sample to the first time the mosquito repellency rate fell below 80% was taken as the duration of effectiveness (unit: h). During the test, the testing environment, mosquito size, and volunteer conditions remained unchanged to ensure the accuracy and comparability of the test data.

[0068] (3) Stability testing method: The accelerated stability test was carried out in accordance with the national standard GB / T 19136-2013 "Test Methods for the Stability of Health Insecticides for Pesticide Registration". Test samples: For each example and comparative example product, intact sealed finished products were taken, with 3 samples in each group and 50 mL for each sample; Test conditions: The samples were placed in an incubator, with the temperature controlled at 50±2°C and the relative humidity at 60±5%, and placed in the dark; Test cycle: The samples were continuously placed for 7 days. The samples were taken out at 0 days (initial state), 1 day, 3 days, 5 days, and 7 days, and the appearance state of the samples was observed and recorded, including whether there were phenomena such as stratification, precipitation, turbidity, color change, and peculiar smell; Stability judgment criteria: If there was no stratification, no precipitation, no obvious turbidity and color change in the samples within 7 days, and no peculiar smell was generated, it was judged as qualified in stability; If any of the above abnormal phenomena occurred, it was judged as unqualified in stability, and at the same time, the time and degree of the occurrence of the abnormal phenomena were recorded in detail.

[0069] (4)Skin irritation test method: The acute skin irritation test on rabbits was carried out in accordance with the national standard GB / T 15670.18-2017 "Test Methods for Pesticide Registration Toxicology - Part 18: Skin Irritation / Corrosion Test". Test animals: 6 healthy white rabbits were selected, with a body weight of 2.0-2.5 kg, 3 males and 3 females. The hair on both sides of the spine on the back of the rabbits was removed 24 hours before the test, and the hair removal area on each side was not less than 3 cm×3 cm, ensuring that the skin was not damaged, red, swollen or abnormal after hair removal; Test samples: The original solutions of each example and comparative example product were taken, and physiological saline was used in the control group; Test steps: 0.5 mL of the test sample was evenly applied to the hairless skin surface on one side of the rabbit, covered and fixed with sterile gauze, and an equal amount of physiological saline was applied to the hairless skin on the other side as a control. The application time was 24 hours; After 24 hours of application, the gauze and residual samples were removed, and the application area was washed with warm water. The reactions of the rabbits' skin, including erythema, edema, erosion, etc., were observed and recorded at 1 hour, 24 hours, 48 hours, and 72 hours after the removal of the samples; Stimulation reaction judgment: Scoring was carried out according to the degree of skin erythema and edema (Erythema: no erythema 0 points, slight erythema 1 point, obvious erythema 2 points, severe erythema 3 points, erythema with erosion 4 points; Edema: no edema 0 points, slight edema 1 point, obvious edema 2 points, severe edema 3 points). The average reaction grade of 6 rabbits was calculated. If the average reaction grade < 1 point, it was judged as non-irritating; if it was 1-2 points, it was judged as slightly irritating; if it was 2-3 points, it was judged as moderately irritating; if it was > 3 points, it was judged as severely irritating.

[0070] (5)Broad-spectrum repellent effect test method: Repellency tests were conducted on dust mites (Dermatophagoides farinae) and bed bugs (Cimexlectularius), respectively, following industry standards and relevant research specifications. Test environment: temperature 25±2℃, relative humidity 70±5%, dark environment; Test insect sources: adult dust mites cultured for 15 days were used, with 100 mites per group; adult bed bugs 7-10 days after emergence were used, with 50 bed bugs per group, all starved for 48 hours before use; Test samples: products from each example and comparative example were diluted to the actual usage concentration (1:10 dilution), with deionized water used as the control group; Test procedure: using the filter membrane contact method, a 9cm diameter qualitative filter paper was divided into two halves... Apply 0.2 mL of the test sample to one half of the sample and an equal volume of the control group solution to the other half. After drying, place the filter paper in a petri dish, place the test insect source in the center of the filter paper, cover the petri dish, and place it in the test environment. After 2 hours, observe and record the number of insects on both sides of the filter paper (sample side and control group side). Calculate the repellency rate: Repellency rate (%) = (number of insects on the control group side - number of insects on the sample side) / number of insects on the control group side × 100%. Repeat the test 3 times for each sample group and take the average value as the final broad-spectrum repellency effect data.

[0071] The test results are shown in Table 1 below: Table 1:

[0072]

[0073] Based on the above performance test data, a comprehensive analysis is conducted on the performance advantages of the technical solution of this invention and the necessity of the design of each core technology.

[0074] From the perspective of core product performance, the mosquito-repellent green essential oils provided in Examples 1-5 of this invention exhibit superior overall performance compared to existing related products (Comparative Examples 1-6) in terms of mosquito-repellent efficiency, duration of effect, system stability, skin safety, and broad-spectrum repellent effect. The mosquito-repellent rates of Examples 1-5 all reach over 91%, with a maximum of 97.2%, and the longest duration of effect is extended to 7.0 hours. In contrast, even Comparative Example 6, which simply replicates existing Inca marigold-related technologies, only achieved a mosquito-repellent rate of 86.7% and a duration of effect of 3.8 hours, significantly lower than the product of this invention. Regarding stability, Examples 1-5 maintained a uniform, transparent state without stratification or sedimentation after accelerated aging at 50°C for 7 days. In contrast, Comparative Example 3, which used traditional additives, Comparative Example 4, which used a simplified process, and Comparative Example 6, which used a simple combination of technologies, all showed varying degrees of stratification or sedimentation. This demonstrates that the green nonionic surfactant and optimized process steps selected in this invention effectively improve the stability of the product system.

[0075] From the perspective of the actual effect of the ingredient combination, Inca marigold essential oil, as the core ingredient, provides the basic support for the product's mosquito-repellent performance. Comparative Example 1 (only compounded with auxiliary essential oils) and Comparative Example 5 (single lemongrass essential oil), lacking this core ingredient, had mosquito-repellent rates of only 65.4% and 82.1%, respectively, with a duration of effect of less than 3.2 hours, far lower than the product of the example using Inca marigold essential oil as the core ingredient. While Comparative Example 2, relying solely on Inca marigold essential oil, had a certain mosquito-repellent effect, due to the lack of synergistic effect from auxiliary essential oils, its mosquito-repellent rate was only 78.6%, its duration of effect was 3.0 hours, and it exhibited slight skin irritation. Compared to Examples 1-5, its overall performance was still significantly inferior. This indicates that the present invention, through the combination of Inca marigold essential oil and specific auxiliary essential oils, achieves enhanced mosquito-repellent effect and improved safety of use.

[0076] From the perspective of the role of adjuvant selection and process optimization, Examples 1-5, which use green nonionic surfactants, all achieved a level of non-irritation to the skin (reaction level 0). Example 3 is also suitable for special populations such as sensitive skin and infants. In contrast, Comparative Example 3, which uses traditional adjuvants, exhibits moderate irritation. In terms of process, the products of the examples that underwent ultrasonic extraction, silica gel column chromatography purification, ultrasonic-assisted compounding, and precise temperature control stabilization treatment retained the core components more fully and the components were more uniformly integrated. Compared with Comparative Example 4, which omitted these optimization steps, the mosquito repellency rate was increased by more than 10%, the duration of effect was extended by 2.5 hours, and the stability was also significantly improved. This indicates that the adjuvant selection and process design of the present invention are important supports for ensuring the comprehensive performance of the product.

[0077] From the perspective of scenario adaptability, Example 5, after being specifically optimized for extreme outdoor high temperature and high humidity environments, still maintains a mosquito repellency rate of 95.3% and a duration of 6.0 hours under conditions of 38℃ and 85% relative humidity. The repellency rates against mites and bedbugs reach 88.6% and 84.2%, respectively. Combined with the basic daily, special population, and broad-spectrum repellency scenarios covered by Examples 1-4, a product system adapted to diverse usage needs has been formed. In contrast, existing related products (Comparative Examples 1-6) can mostly only meet the needs of a single scenario, and their performance degrades significantly in extreme environments, further demonstrating the practical value of the technical solution of this invention.

[0078] In summary, this invention, through the rational selection of core and auxiliary ingredients, the combination of green and environmentally friendly additives, and the optimization of extraction and compounding processes, enables the product to achieve comprehensive advantages in mosquito repellent effect, duration of effect, stability, safety, and adaptability to various scenarios. It effectively solves the problems of limited mosquito repellent efficiency, short duration of effect, insufficient stability, risk of irritation, and limited adaptability of existing mosquito repellent essential oils. It can meet diverse usage needs such as ordinary daily use, adaptation for special groups, and extreme outdoor environments, and has good application prospects.

[0079] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A green mosquito-repellent essential oil, characterized in that, It is composed of the following raw materials: Inca Marigold essential oil, auxiliary plant essential oils, green nonionic surfactants, food-grade ethanol, and deionized water; the auxiliary plant essential oils are selected from at least one of lemongrass essential oil, peppermint essential oil, lavender essential oil, citronella essential oil, chamomile essential oil, rosemary essential oil, and eucalyptus essential oil; the green nonionic surfactants are selected from at least one of Tween 80, polyglycerol fatty acid esters, cocoyl glucoside, and polyglycerol-3-laurate.

2. The mosquito-repellent green essential oil according to claim 1, characterized in that, The mass percentage range of each raw material is as follows: 10 to 30 parts of Inca marigold essential oil, 2 to 14 parts of auxiliary plant essential oils, 2 to 7 parts of green nonionic surfactant, 42 to 68 parts of food-grade ethanol, and 9 to 31 parts of deionized water.

3. The mosquito-repellent green essential oil according to claim 1 or 2, characterized in that, The ingredients also include natural antioxidants, which are selected from at least one of vitamin E and vitamin C, and are present in a mass percentage of 1 part.

4. The mosquito-repellent green essential oil according to any one of claims 1 to 3, characterized in that, The ingredients also include menthol, which is 1 part by weight.

5. A method for preparing a mosquito-repellent green essential oil as described in any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Extraction of Inca Marigold essential oil: Select fresh whole plant of Inca Marigold, remove rotten parts, wash and dry, then crush, add food grade ethanol, extract by ultrasonication, let stand and filter, and distill the filtrate under reduced pressure to recover ethanol to obtain crude essential oil. The crude essential oil is purified by silica gel column chromatography to obtain Inca Marigold essential oil. (2) Blending of compound essential oils: Add the Inca Marigold essential oil and the auxiliary plant essential oils to the reaction vessel according to the ratio, and stir to obtain the compound essential oil; (3) Stabilization treatment: Add green nonionic surfactant to the mixed essential oils, stir, and then add a mixture of food-grade ethanol and deionized water dropwise. Heat and keep warm while stirring to obtain a uniform essential oil system. (4) Post-processing: Filter the essential oil system, seal and let it stand in the dark to obtain mosquito repellent green essential oil.

6. The preparation method according to claim 5, characterized in that, In step (1), the particle size of the crushed Cotyledon Inca is 40 to 60 mesh, the amount of food-grade ethanol added is 5 times the mass of Cotyledon Inca, the temperature of ultrasonic extraction is 35℃, the ultrasonic power is 150 to 180W, and the extraction time is 30 to 45 minutes; the eluent for silica gel column chromatography is a mixture of petroleum ether and ethanol.

7. The preparation method according to claim 5 or 6, characterized in that, In step (2), the stirring temperature is 22 to 30°C, the stirring speed is 250 to 400 revolutions per minute, and the stirring time is 15 to 25 minutes; ultrasonic-assisted dispersion can be performed during the stirring process.

8. The preparation method according to any one of claims 5 to 7, characterized in that, In step (3), the stirring time after adding the green nonionic surfactant is 20 to 30 minutes; after the ethanol and deionized water mixture is added dropwise, the temperature is raised to 30 to 40°C and the stirring time is 30 to 50 minutes.

9. The preparation method according to any one of claims 5 to 8, characterized in that, In step (4), precision filtration is used, and the filter membrane material is polyvinylidene fluoride; the standing temperature is 20 to 25°C, and the standing time is 12 to 36 hours.

10. The preparation method according to any one of claims 5 to 9, characterized in that, In step (4), the filtration process may include an ultraviolet sterilization step; in step (1), the purity of food-grade ethanol is 75% or 95%.

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