Plant essential oil spray with mosquito repelling effect and preparation method thereof

Abstract

The invention relates to the field of mosquito-repelling articles, in particular to a plant essential oil spray with a mosquito-repelling effect and a preparation method of the plant essential oil spray, and the plant essential oil spray comprises the following components in parts by mass: 45-50 parts of an essential oil-loaded modified mesoporous silica carrier; 60 to 70 parts of caprylic / capric glyceride; 3 to 5 parts of hydrogenated polyisobutene; the essential oil loading mass percentage of the essential oil loading modified mesoporous silica carrier is greater than or equal to 65%; the essential oil comprises PMD, citronellol and piperine in a mass ratio of (30-35): (10-12): (0.8-1); and the particle size distribution D90 of the essential oil-loaded modified mesoporous silica carrier is 15-20 [mu] m. According to the scheme, through the high-proportion mesoporous silicon dioxide carrier, the ultrahigh load rate of more than or equal to 65% for a PMD, citronellol and piperine ternary essential oil system is achieved, and the long-time slow-release mosquito repelling effect is achieved.

Description

Technical Field

[0001] This invention relates to the field of mosquito repellent products, and more particularly to a plant essential oil spray with mosquito repellent effect and its preparation method. Background Technology

[0002] Plant essential oil sprays have garnered significant attention in the mosquito repellent field due to their natural, non-irritating, and multifunctional properties. However, current technologies still have significant shortcomings in achieving long-lasting mosquito repellency and skin safety. On the one hand, the problem of the volatile oxidation of active ingredients in natural essential oils has not been effectively solved, resulting in a short duration of mosquito repellency. Conventional sprays require frequent reapplication, and the effective molecules rapidly decay upon contact with the skin. On the other hand, the addition of high concentrations of essential oils may cause skin irritation and allergic reactions, limiting their application in long-term use scenarios.

[0003] In existing technologies, CN110251435B proposes an essential oil spray with mosquito-repellent and anti-itch effects and its preparation method. This method aims to improve product stability and moisturizing effects by combining various essential oils with emulsifiers, moisturizers, and other excipients. However, this technical solution fails to fundamentally solve the problem of easy volatility and oxidation of the active ingredients in essential oils, resulting in a short-lasting mosquito-repellent effect. Furthermore, the use of high-concentration essential oils still carries the risk of skin irritation and allergies. CN116440014B designs a two-layer plant essential oil spray with mosquito-repellent effects. This design avoids the problem of rapid evaporation of essential oils in traditional single-phase systems through a water-oil layered structure and utilizes emollients to solubilize the core mosquito-repellent ingredients to improve stability. However, this technical solution requires shaking before use, making it inconvenient to operate and difficult to ensure consistent dosage each time. Additionally, the layered design has high requirements for storage conditions, which may lead to uneven layering or product failure during transportation or storage.

[0004] The problems indicate that existing plant essential oil sprays still have certain shortcomings in terms of mosquito repellency duration, essential oil stability, skin safety, and ease of use. Summary of the Invention

[0005] To overcome the above shortcomings, this invention provides a plant essential oil spray with mosquito-repellent effect and its preparation method. This invention introduces a modified mesoporous silica carrier to efficiently load essential oil molecules to form a stable sustained-release system, which significantly delays the volatilization of essential oil and prolongs the mosquito-repellent effect. The external surface modification precisely adapts to the skin interface behavior, which not only alleviates the irritation caused by direct contact of essential oil with the skin, but also enhances the adhesion and sustained-release effect to the skin through a dynamic response mechanism.

[0006] To achieve its objectives, the present invention employs the following technical solution: A plant essential oil spray with mosquito-repellent properties, comprising, by weight: Essential oil-loaded modified mesoporous silica carrier: 45-50 parts; Caprylic / capric triglyceride: 60-70 parts; Hydrogenated polyisobutylene: 3-5 parts; The essential oil-loaded modified mesoporous silica carrier has an essential oil loading percentage of ≥65% by mass; the essential oil comprises PMD:citronellol:piperine in a mass ratio of 30-35:10-12:0.8-1; the particle size distribution D of the essential oil-loaded modified mesoporous silica carrier is... 90 It is 15-20μm.

[0007] Preferably, the viscosity of the spray at 25°C is 500-1500 mPa·s.

[0008] Preferably, the average pore size of the mesoporous silica carrier modified with essential oil is 4-8 nm; the water contact angle of the inner wall of the mesoporous pore is ≥120°, and the water contact angle of the outer wall is 70°-85°.

[0009] A method for preparing a plant essential oil spray with mosquito-repellent properties includes the following steps: Step (1): Prepare a modified mesoporous silica support; Step (2): Preparation of essential oil-loaded modified mesoporous silica carrier; Step (3): According to the material ratio, homogenize to obtain a plant essential oil spray with mosquito repellent effect.

[0010] Preferably, the preparation of the modified mesoporous silica support includes the following steps: (1-a) Tetraethyl orthosilicate, hexadecyltrimethylammonium bromide, and pore expander are mixed in a molar ratio of 1:0.9-1.1:0.2-0.4. Ammonia water with a mass fraction of 25%-28% is added to adjust the pH of the system to 8.5-9.5. The mixture is stirred and reacted at 65-85℃ for 6-8 hours. After the reaction is completed, the solid phase is separated by centrifugation. The obtained solid is calcined at 500-600℃ for 4-6 hours to obtain a mesoporous silica support. (1-b) The mesoporous silica support and octadecyltrimethoxysilane were mixed in an anhydrous ethanol at a mass ratio of 100:20-30 and reacted at 75-85℃ for 5-8h. After the reaction was completed, the mixture was washed with ethanol and dried to obtain the hydrophobically modified mesoporous silica support. (1-c) The hydrophobic modified mesoporous silica carrier and polyether modified silicone oil were reacted in toluene at 65-75℃ for 7-9h, and the modified mesoporous silica carrier was obtained by washing and drying with toluene; the amount of polyether modified silicone oil added was 25%-35% of the mass of the hydrophobic modified mesoporous silica carrier.

[0011] The modified mesoporous silica carrier has a hydrophilic surface and a hydrophobic interior.

[0012] Preferably, the pore-expanding agent is 1,3,5-trimethylbenzene.

[0013] Preferably, the process for preparing the essential oil-supported modified mesoporous silica carrier includes: (2-a) The modified mesoporous silica support was added to acetone and treated under vacuum conditions of -45kPa to -55kPa for 25-35 min. The acetone was then filtered out to obtain the pre-wetted modified mesoporous silica support. (2-b) The pre-wetted modified mesoporous silica carrier was added to a mixture of PMD, citronellol and piperine in a mass ratio of 30-35:10-12:0.8-1, and vacuum-treated. Then, the pressure was slowly increased to atmospheric pressure at a rate of 0.8-1.2 kPa / s, and low-frequency ultrasonic treatment at 18-22 kHz and 45-55 W was applied simultaneously to obtain an essential oil-loaded modified mesoporous silica carrier.

[0014] Preferably, the vacuum treatment is performed in three stages, maintaining a temperature of 30-40°C: Phase 1: Maintain -45kPa to -55kPa for 25-35 minutes; Second stage: Adjust to -65kPa to -75kPa and maintain for 25-35 minutes; Phase 3: Adjust to -85kPa to -95kPa and maintain for 22-26 hours.

[0015] Since acetone can volatilize well under low pressure at 30-40℃, the vacuum treatment process also removes a small amount of residual acetone.

[0016] Preferably, the homogenization process includes: mixing essential oil-loaded modified mesoporous silica carrier with caprylic / capric glyceride and hydrogenated polyisobutylene in a certain ratio, and homogenizing at 9500-10500 rpm for 9-11 min to obtain a plant essential oil spray with mosquito repellent effect.

[0017] Compared with existing technologies, this solution has the following advantages: 1. Component Formulation Design: A high proportion of mesoporous silica carrier achieves an ultra-high loading rate of ≥65% for the PMD, citronellol, and piperine ternary essential oil system; the controlled ratio of hydrogenated polyisobutylene (thickener) to glyceryl caprylate (oil phase base) ensures the product achieves a golden viscosity range of 500-1500 mPa·s at 25℃, guaranteeing atomization effectiveness. This formula combines natural safety, long-lasting mosquito repellency, and user-friendliness.

[0018] 2. Process: The modified mesoporous silica carrier forms rigid mesopores through calcination with a pore-expanding agent, and constructs a hydrophobic inner cavity and a hydrophilic outer wall, forming a "slow-release-adsorption" dual-function synergy to improve the mosquito repellency. In the essential oil loading stage, pre-wetting utilizes acetone molecules to expel air from the pores and reduce interfacial tension. The gradual pressurization stage drives the essential oil molecules to fill deeply, removes residual acetone, and the depressurization process is supplemented by ultrasonic oscillation, which reduces the pore rupture rate. Finally, the homogenization process yields a stable finished product. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1

[0021] A method for preparing a plant essential oil spray with mosquito-repellent properties includes the following steps: Step (1): Preparation of modified mesoporous silica support: (1-a) Tetraethyl orthosilicate, hexadecyltrimethylammonium bromide and 1,3,5-trimethylbenzene were mixed in a molar ratio of 1:1:0.3, and 26% ammonia water was added to adjust the pH of the system to 9. The mixture was stirred at 70°C for 7 h. After the reaction was completed, the solid phase was separated by centrifugation, and the obtained solid was calcined at 550°C for 5 h to obtain a mesoporous silica support. (1-b) The mesoporous silica support and octadecyltrimethoxysilane were mixed in anhydrous ethanol at a mass ratio of 100:25 and reacted at 80°C for 6 h. After the reaction was completed, the mixture was washed and dried with ethanol to obtain the hydrophobically modified mesoporous silica support. (1-c) The hydrophobic modified mesoporous silica support was reacted with polyether modified silicone oil in toluene at 70°C for 8 hours. The mixture was washed with toluene and dried to obtain the modified mesoporous silica support. The amount of polyether modified silicone oil added was 30% of the mass of the hydrophobic modified mesoporous silica support. Step (2): Preparation of essential oil-supported modified mesoporous silica carrier: (2-a) The modified mesoporous silica support was added to acetone and treated under vacuum of -50 kPa for 30 min. The acetone was then filtered out to obtain the pre-wetted modified mesoporous silica support. (2-b) The pre-wetted modified mesoporous silica carrier was added to a mixture of PMD, citronellol and piperine in a mass ratio of 32:11:0.9, and vacuum-treated. Then, the pressure was slowly increased to atmospheric pressure at a rate of 1.0 kPa / s, and low-frequency ultrasonic treatment of 20 kHz and 50 W was applied simultaneously to obtain an essential oil-loaded modified mesoporous silica carrier. The vacuum treatment is divided into three stages, maintaining a temperature of 35°C: Phase 1: Maintain -50 kPa for 30 minutes; Second stage: Adjust to -70 kPa and maintain for 30 minutes; Phase 3: Adjust to -90 kPa and maintain for 24 hours; Step (3): By weight, 48 parts of essential oil-loaded modified mesoporous silica carrier, 65 parts of caprylic / capric glyceride, and 4 parts of hydrogenated polyisobutylene are mixed and homogenized at 10,000 rpm for 10 min to obtain a plant essential oil spray with mosquito repellent effect.

[0022] Example 2

[0023] A method for preparing a plant essential oil spray with mosquito-repellent properties includes the following steps: Step (1): Preparation of modified mesoporous silica support: (1-a) Tetraethyl orthosilicate, hexadecyltrimethylammonium bromide, and 1,3,5-trimethylbenzene were mixed in a molar ratio of 1:1:0.4. Ammonia water with a mass fraction of 26% was added to adjust the pH of the system to 9.0. The mixture was stirred at 85°C for 8 hours. After the reaction was completed, the solid phase was separated by centrifugation. The obtained solid was calcined at 600°C for 4 hours to obtain a mesoporous silica support. (1-b) The mesoporous silica support and octadecyltrimethoxysilane were mixed in anhydrous ethanol at a mass ratio of 100:30 and reacted at 85°C for 5-8 hours. After the reaction was completed, the mixture was washed and dried with ethanol to obtain the hydrophobically modified mesoporous silica support. (1-c) The hydrophobic modified mesoporous silica support was reacted with polyether modified silicone oil in toluene at 75°C for 7 h, and the mixture was washed and dried with toluene to obtain the modified mesoporous silica support; the amount of polyether modified silicone oil added was 35% of the mass of the hydrophobic modified mesoporous silica support; Step (2): Preparation of essential oil-supported modified mesoporous silica carrier: (2-a) The modified mesoporous silica support was added to acetone and treated under vacuum of -55 kPa for 25 min. The acetone was then filtered out to obtain the pre-wetted modified mesoporous silica support. (2-b) The pre-wetted modified mesoporous silica carrier was added to a mixture of PMD, citronellol and piperine in a mass ratio of 35:12:1, and vacuum-treated. Then, the pressure was slowly increased to atmospheric pressure at a rate of 1.0 kPa / s, and low-frequency ultrasonic treatment of 20 kHz and 50 W was applied simultaneously to obtain an essential oil-loaded modified mesoporous silica carrier. The vacuum treatment is divided into three stages, maintaining a temperature of 35°C: Phase 1: Maintain -50 kPa for 30 minutes; Second stage: Adjust to -70 kPa and maintain for 30 minutes; Phase 3: Adjust to -90 kPa and maintain for 24 hours; Step (3): By weight, 50 parts of essential oil-loaded modified mesoporous silica carrier, 70 parts of caprylic / capric glyceride, and 5 parts of hydrogenated polyisobutylene are mixed and homogenized at 10,000 rpm for 10 min to obtain a plant essential oil spray with mosquito repellent effect.

[0024] Example 3

[0025] A method for preparing a plant essential oil spray with mosquito-repellent properties includes the following steps: Step (1): Preparation of modified mesoporous silica support: (1-a) Tetraethyl orthosilicate, hexadecyltrimethylammonium bromide, and 1,3,5-trimethylbenzene were mixed in a molar ratio of 1:0.9:0.2. Ammonia water with a mass fraction of 26% was added to adjust the pH of the system to 9.0. The mixture was stirred at 65°C for 8 hours. After the reaction was completed, the solid phase was separated by centrifugation. The obtained solid was calcined at 500°C for 6 hours to obtain a mesoporous silica support. (1-b) The mesoporous silica support and octadecyltrimethoxysilane were mixed in anhydrous ethanol at a mass ratio of 100:20 and reacted at 75°C for 7 h. After the reaction was completed, the mixture was washed with ethanol and dried to obtain the hydrophobically modified mesoporous silica support. (1-c) The hydrophobic modified mesoporous silica support was reacted with polyether modified silicone oil in toluene at 65°C for 9 h, and the mixture was washed and dried with toluene to obtain the modified mesoporous silica support; the amount of polyether modified silicone oil added was 25% of the mass of the hydrophobic modified mesoporous silica support; Step (2): Preparation of essential oil-supported modified mesoporous silica carrier: (2-a) The modified mesoporous silica support was added to acetone and treated under a vacuum of -45 kPa for 35 min. The acetone was then filtered out to obtain the pre-wetted modified mesoporous silica support. (2-b) The pre-wetted modified mesoporous silica carrier was added to a mixture of PMD, citronellol and piperine in a mass ratio of 30:10:0.8, and vacuum-treated. Then, the pressure was slowly increased to atmospheric pressure at a rate of 1.0 kPa / s, and low-frequency ultrasonic treatment of 20 kHz and 50 W was applied simultaneously to obtain an essential oil-loaded modified mesoporous silica carrier. The vacuum treatment is divided into three stages, maintaining a temperature of 35°C: Phase 1: Maintain -50 kPa for 30 minutes; Second stage: Adjust to -70 kPa and maintain for 30 minutes; Phase 3: Adjust to -90 kPa and maintain for 24 hours; Step (3): By weight, 45 parts of essential oil-loaded modified mesoporous silica carrier, 60 parts of caprylic / capric glyceride, and 3 parts of hydrogenated polyisobutylene are mixed and homogenized at 10,000 rpm for 10 min to obtain a plant essential oil spray with mosquito repellent effect.

[0026] Comparative Example 1 The difference from Example 1 is that a mesoporous silica carrier was not used: A method for preparing a plant essential oil spray with mosquito-repellent properties includes the following steps: By weight, 48 parts of a mixture of PMD, citronellol, and piperine in a mass ratio of 32:11:0.9, 65 parts of caprylic / capric glyceride, and 4 parts of hydrogenated polyisobutylene were mixed and homogenized at 10,000 rpm for 10 minutes to prepare a plant essential oil spray with mosquito-repellent effect.

[0027] Comparative Example 2 The difference from Example 1 is that ordinary silica powder is used: A method for preparing a plant essential oil spray with mosquito-repellent properties includes the following steps: Step (1): Preparation of modified mesoporous silica support: Silica powder and octadecyltrimethoxysilane were mixed at a mass ratio of 100:25 and added to anhydrous ethanol. The mixture was reacted at 80°C for 6 hours. After the reaction, the mixture was washed and dried with ethanol. Then, it was reacted with polyether-modified silicone oil in toluene at 70°C for 8 hours. The mixture was washed and dried with toluene to obtain the modified silica carrier. The amount of polyether-modified silicone oil added was 30% of the mass of the hydrophobic modified mesoporous silica carrier. Step (2): Preparation of essential oil-supported modified silica carrier: (2-a) The modified silica support was added to acetone and treated under vacuum of -50 kPa for 30 min. The acetone was then filtered out to obtain the pre-wetted modified silica support. (2-b) The pre-wetted modified silica carrier was added to a mixture of PMD, citronellol and piperine in a mass ratio of 32:11:0.9, and vacuum-treated. Then, the pressure was slowly increased to atmospheric pressure at a rate of 1.0 kPa / s, and low-frequency ultrasonic treatment of 20 kHz and 50 W was applied simultaneously to obtain an essential oil-loaded modified silica carrier. The vacuum treatment is divided into three stages, maintaining a temperature of 35°C: Phase 1: Maintain -50 kPa for 30 minutes; Second stage: Adjust to -70 kPa and maintain for 30 minutes; Phase 3: Adjust to -90 kPa and maintain for 24 hours; Step (3): By weight, 48 parts of essential oil-loaded modified silica carrier, 65 parts of caprylic / capric glyceride, and 4 parts of hydrogenated polyisobutylene are mixed and homogenized at 10,000 rpm for 10 min to obtain a plant essential oil spray with mosquito repellent effect.

[0028] Comparative Example 3 The difference from Example 1 is that no hydrophobically modified mesoporous silica support was prepared: A method for preparing a plant essential oil spray with mosquito-repellent properties includes the following steps: Step (1): Preparation of modified mesoporous silica support: (1-a) Tetraethyl orthosilicate, hexadecyltrimethylammonium bromide and 1,3,5-trimethylbenzene were mixed in a molar ratio of 1:1:0.3, and 26% ammonia water was added to adjust the pH of the system to 9. The mixture was stirred at 70°C for 7 h. After the reaction was completed, the solid phase was separated by centrifugation, and the obtained solid was calcined at 550°C for 5 h to obtain a mesoporous silica support. (1-b) Mesoporous silica support and polyether-modified silicone oil were reacted in toluene at 70°C for 8 hours, and the mixture was washed and dried with toluene to obtain modified mesoporous silica support; the amount of polyether-modified silicone oil added was 30% of the mass of the hydrophobic modified mesoporous silica support; Step (2): Preparation of essential oil-supported modified mesoporous silica carrier: (2-a) The modified mesoporous silica support was added to acetone and treated under vacuum of -50 kPa for 30 min. The acetone was then filtered out to obtain the pre-wetted modified mesoporous silica support. (2-b) The pre-wetted modified mesoporous silica carrier was added to a mixture of PMD, citronellol and piperine in a mass ratio of 32:11:0.9, and vacuum-treated. Then, the pressure was slowly increased to atmospheric pressure at a rate of 1.0 kPa / s, and low-frequency ultrasonic treatment of 20 kHz and 50 W was applied simultaneously to obtain an essential oil-loaded modified mesoporous silica carrier. The vacuum treatment is divided into three stages, maintaining a temperature of 35°C: Phase 1: Maintain -50 kPa for 30 minutes; Second stage: Adjust to -70 kPa and maintain for 30 minutes; Phase 3: Adjust to -90 kPa and maintain for 24 hours; Step (3): By weight, 48 parts of essential oil-loaded modified mesoporous silica carrier, 65 parts of caprylic / capric glyceride, and 4 parts of hydrogenated polyisobutylene are mixed and homogenized at 10,000 rpm for 10 min to obtain a plant essential oil spray with mosquito repellent effect.

[0029] Comparative Example 4 The difference from Example 1 is that polyether-modified silicone oil was not used for modification: A method for preparing a plant essential oil spray with mosquito-repellent properties includes the following steps: Step (1): Preparation of modified mesoporous silica support: (1-a) Tetraethyl orthosilicate, hexadecyltrimethylammonium bromide and 1,3,5-trimethylbenzene were mixed in a molar ratio of 1:1:0.3, and 26% ammonia water was added to adjust the pH of the system to 9. The mixture was stirred at 70°C for 7 h. After the reaction was completed, the solid phase was separated by centrifugation, and the obtained solid was calcined at 550°C for 5 h to obtain a mesoporous silica support. (1-b) The mesoporous silica support and octadecyltrimethoxysilane were mixed in anhydrous ethanol at a mass ratio of 100:25 and reacted at 80°C for 6 h. After the reaction was completed, the mixture was washed with ethanol and dried to obtain the modified mesoporous silica support. Step (2): Preparation of essential oil-supported modified mesoporous silica carrier: (2-a) The modified mesoporous silica support was added to acetone and treated under vacuum of -50 kPa for 30 min. The acetone was then filtered out to obtain the pre-wetted modified mesoporous silica support. (2-b) The pre-wetted modified mesoporous silica carrier was added to a mixture of PMD, citronellol and piperine in a mass ratio of 32:11:0.9, and vacuum-treated. Then, the pressure was slowly increased to atmospheric pressure at a rate of 1.0 kPa / s, and low-frequency ultrasonic treatment of 20 kHz and 50 W was applied simultaneously to obtain an essential oil-loaded modified mesoporous silica carrier. The vacuum treatment is divided into three stages, maintaining a temperature of 35°C: Phase 1: Maintain -50 kPa for 30 minutes; Second stage: Adjust to -70 kPa and maintain for 30 minutes; Phase 3: Adjust to -90 kPa and maintain for 24 hours; Step (3): By weight, 48 parts of essential oil-loaded modified mesoporous silica carrier, 65 parts of caprylic / capric glyceride, and 4 parts of hydrogenated polyisobutylene are mixed and homogenized at 10,000 rpm for 10 min to obtain a plant essential oil spray with mosquito repellent effect.

[0030] Comparative Example 5 The difference from Example 1 is that the modified mesoporous silica was not pre-wetted: A method for preparing a plant essential oil spray with mosquito-repellent properties includes the following steps: Step (1): Preparation of modified mesoporous silica support: (1-a) Tetraethyl orthosilicate, hexadecyltrimethylammonium bromide and 1,3,5-trimethylbenzene were mixed in a molar ratio of 1:1:0.3, and 26% ammonia water was added to adjust the pH of the system to 9. The mixture was stirred at 70°C for 7 h. After the reaction was completed, the solid phase was separated by centrifugation, and the obtained solid was calcined at 550°C for 5 h to obtain a mesoporous silica support. (1-b) The mesoporous silica support and octadecyltrimethoxysilane were mixed in anhydrous ethanol at a mass ratio of 100:25 and reacted at 80°C for 6 h. After the reaction was completed, the mixture was washed and dried with ethanol to obtain the hydrophobically modified mesoporous silica support. (1-c) The hydrophobic modified mesoporous silica support was reacted with polyether modified silicone oil in toluene at 70°C for 8 hours. The mixture was washed with toluene and dried to obtain the modified mesoporous silica support. The amount of polyether modified silicone oil added was 30% of the mass of the hydrophobic modified mesoporous silica support. Step (2): Preparation of essential oil-supported modified mesoporous silica carrier: Modified mesoporous silica carrier was added to a mixture of PMD, citronellol, and piperine in a mass ratio of 32:11:0.9, and vacuum-treated. Then, the pressure was slowly increased to atmospheric pressure at a rate of 1.0 kPa / s, and low-frequency ultrasonic treatment of 20 kHz and 50 W was applied simultaneously to obtain essential oil-loaded modified mesoporous silica carrier. The vacuum treatment is divided into three stages, maintaining a temperature of 35°C: Phase 1: Maintain -50 kPa for 30 minutes; Second stage: Adjust to -70 kPa and maintain for 30 minutes; Phase 3: Adjust to -90 kPa and maintain for 24 hours; Step (3): By weight, 48 parts of essential oil-loaded modified mesoporous silica carrier, 65 parts of caprylic / capric glyceride, and 4 parts of hydrogenated polyisobutylene are mixed and homogenized at 10,000 rpm for 10 min to obtain a plant essential oil spray with mosquito repellent effect.

[0031] Comparative Example 6 The difference from Example 1 is that step (2-b) is not vacuum treated: A method for preparing a plant essential oil spray with mosquito-repellent properties includes the following steps: Step (1): Preparation of modified mesoporous silica support: (1-a) Tetraethyl orthosilicate, hexadecyltrimethylammonium bromide and 1,3,5-trimethylbenzene were mixed in a molar ratio of 1:1:0.3, and 26% ammonia water was added to adjust the pH of the system to 9. The mixture was stirred at 70°C for 7 h. After the reaction was completed, the solid phase was separated by centrifugation, and the obtained solid was calcined at 550°C for 5 h to obtain a mesoporous silica support. (1-b) The mesoporous silica support and octadecyltrimethoxysilane were mixed in anhydrous ethanol at a mass ratio of 100:25 and reacted at 80°C for 6 h. After the reaction was completed, the mixture was washed and dried with ethanol to obtain the hydrophobically modified mesoporous silica support. (1-c) The hydrophobic modified mesoporous silica support was reacted with polyether modified silicone oil in toluene at 70°C for 8 hours. The mixture was washed with toluene and dried to obtain the modified mesoporous silica support. The amount of polyether modified silicone oil added was 30% of the mass of the hydrophobic modified mesoporous silica support. Step (2): Preparation of essential oil-supported modified mesoporous silica carrier: (2-a) The modified mesoporous silica support was added to acetone and treated under vacuum of -50 kPa for 30 min. The acetone was then filtered out to obtain the pre-wetted modified mesoporous silica support. (2-b) The pre-wetted modified mesoporous silica carrier was added to a mixture of PMD, citronellol and piperine in a mass ratio of 32:11:0.9 and subjected to low-frequency ultrasonic treatment at 20kHz and 50W for 24h to obtain an essential oil-loaded modified mesoporous silica carrier. Step (3): By weight, 48 parts of essential oil-loaded modified mesoporous silica carrier, 65 parts of caprylic / capric glyceride, and 4 parts of hydrogenated polyisobutylene are mixed and homogenized at 10,000 rpm for 10 min to obtain a plant essential oil spray with mosquito repellent effect.

[0032] Comparative Example 7 The difference from Example 1 is that an excess of essential oil-loaded modified mesoporous silica carrier is used: A method for preparing a plant essential oil spray with mosquito-repellent properties includes the following steps: Step (1): Preparation of modified mesoporous silica support: (1-a) Tetraethyl orthosilicate, hexadecyltrimethylammonium bromide and 1,3,5-trimethylbenzene were mixed in a molar ratio of 1:1:0.3, and 26% ammonia water was added to adjust the pH of the system to 9. The mixture was stirred at 70°C for 7 h. After the reaction was completed, the solid phase was separated by centrifugation, and the obtained solid was calcined at 550°C for 5 h to obtain a mesoporous silica support. (1-b) The mesoporous silica support and octadecyltrimethoxysilane were mixed in anhydrous ethanol at a mass ratio of 100:25 and reacted at 80°C for 6 h. After the reaction was completed, the mixture was washed and dried with ethanol to obtain the hydrophobically modified mesoporous silica support. (1-c) The hydrophobic modified mesoporous silica support was reacted with polyether modified silicone oil in toluene at 70°C for 8 hours. The mixture was washed with toluene and dried to obtain the modified mesoporous silica support. The amount of polyether modified silicone oil added was 30% of the mass of the hydrophobic modified mesoporous silica support. Step (2): Preparation of essential oil-supported modified mesoporous silica carrier: (2-a) The modified mesoporous silica support was added to acetone and treated under vacuum of -50 kPa for 30 min. The acetone was then filtered out to obtain the pre-wetted modified mesoporous silica support. (2-b) The pre-wetted modified mesoporous silica carrier was added to a mixture of PMD, citronellol and piperine in a mass ratio of 32:11:0.9, and vacuum-treated. Then, the pressure was slowly increased to atmospheric pressure at a rate of 1.0 kPa / s, and low-frequency ultrasonic treatment of 20 kHz and 50 W was applied simultaneously to obtain an essential oil-loaded modified mesoporous silica carrier. The vacuum treatment is divided into three stages, maintaining a temperature of 35°C: Phase 1: Maintain -50 kPa for 30 minutes; Second stage: Adjust to -70 kPa and maintain for 30 minutes; Phase 3: Adjust to -90 kPa and maintain for 24 hours; Step (3): By weight, 60 parts of essential oil-loaded modified mesoporous silica carrier, 65 parts of caprylic / capric glyceride, and 4 parts of hydrogenated polyisobutylene are mixed and homogenized at 10,000 rpm for 10 min to obtain a plant essential oil spray with mosquito repellent effect.

[0033] Comparative Example 8 The difference from Example 1 is that the essential oil-loaded modified mesoporous silica carrier is insufficient: A method for preparing a plant essential oil spray with mosquito-repellent properties includes the following steps: Step (1): Preparation of modified mesoporous silica support: (1-a) Tetraethyl orthosilicate, hexadecyltrimethylammonium bromide and 1,3,5-trimethylbenzene were mixed in a molar ratio of 1:1:0.3, and 26% ammonia water was added to adjust the pH of the system to 9. The mixture was stirred at 70°C for 7 h. After the reaction was completed, the solid phase was separated by centrifugation, and the obtained solid was calcined at 550°C for 5 h to obtain a mesoporous silica support. (1-b) The mesoporous silica support and octadecyltrimethoxysilane were mixed in anhydrous ethanol at a mass ratio of 100:25 and reacted at 80°C for 6 h. After the reaction was completed, the mixture was washed and dried with ethanol to obtain the hydrophobically modified mesoporous silica support. (1-c) The hydrophobic modified mesoporous silica support was reacted with polyether modified silicone oil in toluene at 70°C for 8 hours. The mixture was washed with toluene and dried to obtain the modified mesoporous silica support. The amount of polyether modified silicone oil added was 30% of the mass of the hydrophobic modified mesoporous silica support. Step (2): Preparation of essential oil-supported modified mesoporous silica carrier: (2-a) The modified mesoporous silica support was added to acetone and treated under vacuum of -50 kPa for 30 min. The acetone was then filtered out to obtain the pre-wetted modified mesoporous silica support. (2-b) The pre-wetted modified mesoporous silica carrier was added to a mixture of PMD, citronellol and piperine in a mass ratio of 32:11:0.9, and vacuum-treated. Then, the pressure was slowly increased to atmospheric pressure at a rate of 1.0 kPa / s, and low-frequency ultrasonic treatment of 20 kHz and 50 W was applied simultaneously to obtain an essential oil-loaded modified mesoporous silica carrier. The vacuum treatment is divided into three stages, maintaining a temperature of 35°C: Phase 1: Maintain -50 kPa for 30 minutes; Second stage: Adjust to -70 kPa and maintain for 30 minutes; Phase 3: Adjust to -90 kPa and maintain for 24 hours; Step (3): By weight, 30 parts of essential oil-loaded modified mesoporous silica carrier, 65 parts of caprylic / capric glyceride, and 4 parts of hydrogenated polyisobutylene are mixed and homogenized at 10,000 rpm for 10 min to obtain a plant essential oil spray with mosquito repellent effect.

[0034] Performance testing: I. Carrier structural parameters and essential oil loading performance are shown in Table 1.

[0035] Detection method: D 90 Laser particle size analyzer detection; Pore ​​size: N2 adsorption-desorption (BJH) ISO 15901-2; Inner wall contact angle: calculated using mercury porosimetry and the Washburn equation; Outer wall contact angle: Powder compression method ASTM D7334; Essential oil loading rate: Soxhlet extraction for 6 hours (toluene) + GC / MS quantification.

[0036] Table 1 Carrier structural parameters and essential oil loading performance experimental group <![CDATA[D 90 (μm)]]> Average pore size (nm) Inner wall contact angle (°) Outer wall contact angle (°) Essential oil loading rate (%) Example 1 17.2±0.3 4.5±0.1 125±2 76±2 68.5±1.2 Example 2 18.6±0.4 7.8±0.2 128±3 82±3 69.1±1.5 Example 3 15.9±0.2 5.2±0.1 122±2 73±2 67.3±1.0 Comparative Example 1 / / / / / Comparative Example 2 22.4±0.6 / / 92±4 16.2±2.1 Comparative Example 3 16.8±0.3 4.7±0.1 89±3 65±3 52.4±1.8 Comparative Example 4 17.1±0.3 4.6±0.1 126±2 138±4 67.8±1.3 Comparative Example 5 17.3±0.3 4.5±0.1 124±2 77±2 53.7±1.6 Comparative Example 6 17.0±0.3 4.5±0.1 123±2 75±2 41.9±1.9 Comparative Example 7 16.9±0.4 4.4±0.1 121±2 74±2 65.2±1.4 Comparative Example 8 18.1±0.3 5.0±0.1 127±3 80±3 64.8±1.3 II. The performance and mosquito-repellent effect of the spray are shown in Table 2.

[0037] Detection method: Viscosity: Rotational viscometer ISO 2555; Dv50: Laser Diffraction Spray Analyzer ISO 21501-3; Full protection time: WHO arm exposure test.

[0038] Table 2. Performance and mosquito-repellent effect of sprays experimental group Viscosity (mPa·s) Fog droplet Dv50 (μm) Full protection time (h) Example 1 820±25 38.5±1.2 6.1±0.3 Example 2 1120±35 42.1±1.5 5.7±0.4 Example 3 680±20 36.7±1.0 5.9±0.3 Comparative Example 1 340±15 85.6±3.5 1.5±0.2 Comparative Example 2 1050±40 68.9±2.4 3.2±0.3 Comparative Example 3 750±28 39.2±1.3 4.3±0.3 Comparative Example 4 1850±50 47.5±1.6 4.9±0.4 Comparative Example 5 870±30 39.8±1.4 3.4±0.3 Comparative Example 6 835±32 37.9±1.3 2.8±0.2 Comparative Example 7 1860±55 53.6±1.8 5.3±0.4 Comparative Example 8 305±12 31.5±1.0 3.1±0.2 The data results show that Examples 1-3 have better mosquito repellent effects than Comparative Examples 1-8, which is attributed to the formulation design of this solution and the sustained-release effect of the essential oil.

[0039] The difference between Comparative Example 1 and Example 1 is that the latter lacks a mesoporous carrier sustained-release system, and the essential oil is directly exposed to the environment. Terpenoid molecules such as PMD are rapidly released due to their high volatility, and direct contact with the skin leads to a significant increase in irritation.

[0040] The difference between Comparative Example 2 and Example 1 is that ordinary silica was used, which did not form an ordered mesoporous structure, had a small specific surface area, and the essential oil molecules were physically adsorbed rather than anchored, resulting in a large number of them falling off during the vacuum loading stage. The high contact angle also hindered skin wetting.

[0041] The difference between Comparative Example 3 and Example 1 is that Comparative Example 3 lacks hydrophobic modification, and the essential oil molecules cannot penetrate deep into the pores under vacuum gradient, resulting in a low loading rate.

[0042] The difference between Comparative Example 4 and Example 1 is that the lack of hydrophilic modification and the hydrophobic outer wall caused wetting failure. The adsorption effect of the essential oil-loaded modified mesoporous silica carrier particles was poor. In addition, in caprylic and caprylic glycerides, the hydrophobic surface caused a surge in interparticle capillary attraction, resulting in an increase in viscosity.

[0043] The difference between Comparative Example 5 and Example 1 is that Comparative Example 5 was not pre-wetted, and the residual air in the pores prevented the essential oil molecules from penetrating deep into the pores under the vacuum gradient, resulting in a low loading rate.

[0044] The difference between Comparative Example 6 and Example 1 is that there is no vacuum gradient, and the atmospheric pressure environment makes the essential oil penetration dependent on molecular Brownian motion, which also leads to a low loading rate.

[0045] The difference between Comparative Example 7 and Example 1 is that the excess of essential oil-loaded modified mesoporous silica carrier (more than 50% carrier ratio) leads to the formation of a percolation network in the oil phase. Hydrogenated polyisobutylene crosslinks into a gel structure between particles, resulting in a sharp increase in viscosity that destroys the atomization rheological properties. During spraying, droplets carrying overloaded particles collide with the skin, causing mechanical irritation.

[0046] The difference between Comparative Example 8 and Example 1 is that the essential oil loading modified mesoporous silica carrier is insufficient, which weakens the sustained-release effect of the essential oil.

Claims

1. A plant essential oil spray with mosquito-repellent properties, characterized in that, By weight, it includes: Essential oil-loaded modified mesoporous silica carrier: 45-50 parts; Caprylic / capric triglyceride: 60-70 parts; Hydrogenated polyisobutylene: 3-5 parts; The essential oil-loaded modified mesoporous silica carrier has an essential oil loading percentage of ≥65% by mass; the essential oil comprises PMD:citronellol:piperine in a mass ratio of 30-35:10-12:0.8-1; the particle size distribution D of the essential oil-loaded modified mesoporous silica carrier is... 90 It is 15-20μm.

2. The plant essential oil spray with mosquito-repellent effect as described in claim 1, characterized in that, The viscosity of the spray at 25°C is 500-1500 mPa·s.

3. The plant essential oil spray with mosquito-repellent effect as described in claim 1, characterized in that, The water contact angle of the inner wall of the mesoporous silica carrier modified with essential oil loading is ≥120°, and the water contact angle of the outer wall is 70°-85°.

4. A method for preparing a plant essential oil spray with mosquito-repellent effect as described in any one of claims 1-3, characterized in that, Includes the following steps: Step (1): Prepare a modified mesoporous silica support; Step (2): Preparation of essential oil-loaded modified mesoporous silica carrier; Step (3): According to the material ratio, homogenize to obtain a plant essential oil spray with mosquito repellent effect.

5. The method for preparing the plant essential oil spray with mosquito-repellent effect as described in claim 4, characterized in that, The preparation of modified mesoporous silica carriers includes the following steps: (1-a) Tetraethyl orthosilicate, hexadecyltrimethylammonium bromide, and pore expander are mixed in a molar ratio of 1:0.9-1.1:0.2-0.4, the pH is adjusted to 8.5-9.5, and the mixture is stirred at 65-85℃ for 6-8 hours. The solid phase is separated, and the resulting solid is calcined at 500-600℃ for 4-6 hours to obtain a mesoporous silica support. (1-b) The mesoporous silica support and octadecyltrimethoxysilane were mixed in an anhydrous ethanol at a mass ratio of 100:20-30 and reacted at 75-85℃ for 5-8h. After the reaction was completed, the mixture was washed and dried to obtain the hydrophobically modified mesoporous silica support. (1-c) The hydrophobic modified mesoporous silica support and polyether modified silicone oil were reacted in toluene at 65-75℃ for 7-9h, and the modified mesoporous silica support was obtained by washing and drying with toluene.

6. The method for preparing the plant essential oil spray with mosquito-repellent effect as described in claim 5, characterized in that, The amount of polyether-modified silicone oil added is 25%-35% of the mass of the hydrophobic modified mesoporous silica carrier.

7. The method for preparing the plant essential oil spray with mosquito-repellent effect as described in claim 5, characterized in that, The pore-expanding agent is 1,3,5-trimethylbenzene.

8. The method for preparing the plant essential oil spray with mosquito-repellent effect as described in claim 4, characterized in that, The process of preparing essential oil-loaded modified mesoporous silica carriers includes: (2-a) The modified mesoporous silica support was added to acetone and treated under vacuum conditions of -45kPa to -55kPa for 25-35 min. The acetone was then filtered out to obtain the pre-wetted modified mesoporous silica support. (2-b) The pre-wetted modified mesoporous silica carrier was added to a mixture of PMD, citronellol and piperine in a mass ratio of 30-35:10-12:0.8-1, vacuum treated, then raised to atmospheric pressure and simultaneously ultrasonic treated to obtain an essential oil-loaded modified mesoporous silica carrier.

9. The method for preparing the plant essential oil spray with mosquito-repellent effect as described in claim 8, characterized in that, The vacuum treatment is divided into three stages, maintaining a temperature of 30-40℃: Phase 1: Maintain -45kPa to -55kPa for 25-35 minutes; Second stage: Adjust to -65kPa to -75kPa and maintain for 25-35 minutes; Phase 3: Adjust to -85kPa to -95kPa and maintain for 22-26 hours.

10. The method for preparing the plant essential oil spray with mosquito-repellent effect as described in claim 4, characterized in that, The homogenization process includes: mixing essential oil-loaded modified mesoporous silica carrier with caprylic / capric glyceride and hydrogenated polyisobutylene in a certain ratio, and homogenizing at 9500-10500 rpm for 9-11 min to obtain a plant essential oil spray with mosquito repellent effect.