Environment-friendly mosquito-repelling electric mosquito coil liquid with bio-based solvent and preparation method thereof

Abstract

The present application relates to mosquito liquid technical field, disclose a kind of environmental protection type mosquito repellent electric mosquito coil liquid with bio-based solvent and its preparation method, the electric mosquito coil liquid by mass percentage, including the following components: bio-based solvent 80%~85%, active ingredient 0.8%~1.9%, antioxidant 0.05%~0.2%, stabilizer 0.1%~0.5%, the rest is C1-C3 alcohol;Its preparation method includes: active ingredient and part bio-based solvent are dissolved to obtain active pre-solution;Remaining bio-based solvent is mixed with antioxidant, stabilizer to obtain main mixed solution;Active pre-solution is added to main mixed solution and homogenization treatment is carried out;Then in turn degassing treatment, standing ripening, filtration, filling, sealing, finished product is obtained.The present application uses bio-based solvent to replace traditional petroleum-based solvent, renewable, low irritation, and volatile uniform and stable, suitable for infant and the environment of sensitive population such as old people, and environmental protection is good.

Description

Technical Field

[0001] This invention relates to the field of mosquito repellent liquid technology, and in particular to an environmentally friendly electric mosquito repellent liquid using a bio-based solvent and its preparation method. Background Technology

[0002] Electric mosquito repellent liquid is a household hygiene and insecticidal product that uses a heating element to continuously release the active ingredients into the air to repel and kill mosquitoes. It is widely used in homes, offices, and other places due to its ease of use and long-lasting effect. Currently, most commercially available electric mosquito repellent liquids use petroleum-based solvents such as deodorized kerosene and C10-C13 isoalkanes as carriers, combined with pyrethroid active ingredients (such as chlorpyrifos and tetrafluoromethrin). These solvents have good solubility for the active ingredients and a suitable evaporation rate.

[0003] However, petroleum-based solvents are derived from non-renewable fossil resources, which contradicts the requirements of green environmental protection and sustainable development. More importantly, the evaporation rate of such solvents is greatly affected by heating temperature and environmental fluctuations. In the initial stage of use, excessively rapid evaporation leads to an over-release of active ingredients, while insufficient evaporation in the later stages results in a decreased mosquito-repelling effect and poor evaporation uniformity. At the same time, petroleum-based solvents may produce trace amounts of oxidation byproducts under long-term continuous heating conditions. Long-term inhalation of their volatile organic compounds poses a potential respiratory irritation risk to sensitive groups such as infants, the elderly, and those with allergies. Summary of the Invention

[0004] The purpose of this invention is to provide an environmentally friendly electric mosquito repellent liquid using a bio-based solvent and its preparation method, which solves the problems of existing electric mosquito repellent liquids relying on petroleum-based solvents, resulting in non-renewability, unstable evaporation rate, and potential irritation to sensitive populations.

[0005] To achieve the above objectives, the present invention provides an environmentally friendly electric mosquito repellent liquid using a bio-based solvent, comprising the following components by weight percentage: Bio-based solvents: 80%–85%; Active ingredient: 0.8%–1.9%; Antioxidant: 0.05%–0.2%; Stabilizer: 0.1%–0.5%; The balance is C1-C3 alcohols; The active ingredient is one or both of chlorfluazuron and tetrafluazuron.

[0006] The mass percentage of the chlorpyrifos is 0.5% to 1.2%.

[0007] The mass percentage of the tetrafluoromethrin is 0.3% to 0.7%.

[0008] The bio-based solvent is selected from one or more compound mixtures of lactate esters, vegetable oil methyl esters, and bio-based glycol ethers.

[0009] The bio-based solvent is a compound mixture of dipropylene glycol methyl ether and ethyl lactate, with a mass ratio of 60-80:20-40.

[0010] The antioxidant is tocopherol, butylated hydroxyanisole, or butylated hydroxytoluene; the stabilizer is epoxidized soybean oil or epoxidized linseed oil.

[0011] On the other hand, the present invention also includes a preparation method, comprising the following steps: The active ingredient in the formulation was dissolved with a portion of the bio-based solvent at 20℃~40℃ to obtain an active pre-solution; Then, the remaining bio-based solvent is mixed with antioxidants and stabilizers, and stirred until homogeneous to obtain the main mixture; Then, the active pre-solution is added to the main mixture under stirring, and homogenization is carried out for 15-30 minutes to obtain a homogeneous mixture; The homogeneous mixture is degassed and then allowed to stand for aging. After aging and filtration, the homogeneous mixture is filled into electric mosquito repellent liquid bottles and sealed to obtain the finished product.

[0012] The amount of the bio-based solvent used is 10% to 30% of the total amount of bio-based solvent; the homogenization speed is 300 to 600 rpm.

[0013] This invention discloses an environmentally friendly electric mosquito repellent liquid using bio-based solvents and its preparation method. The liquid primarily uses 80%–85% bio-based solvents, replacing traditional petroleum-based deodorized kerosene or C10-C13 alkanes. The raw materials are derived from renewable plant resources, resulting in a low carbon footprint and meeting the requirements of green environmental protection and sustainable development. Secondly, by optimizing the bio-based solvent system and combining it with specific amounts of chlorpyrifos and / or tetrafluoromethrin, along with the addition of antioxidants and stabilizers, the evaporation rate of the active ingredient fluctuates by less than ±10% during continuous heating for over 360 hours, overcoming the defect of petroleum-based solvents being "too concentrated in the early stages and ineffective in the later stages." Thirdly, bio-based solvents are inherently low in toxicity and irritation, making them safer for infants, the elderly, and those with allergies with long-term inhalation, and they do not produce the irritating oxidative byproducts that may be generated when petroleum-based solvents are heated. Finally, the preparation method of this invention employs steps such as room-temperature pre-dissolution, homogenization mixing, vacuum degassing, and static curing, eliminating the need for high temperature and high pressure. The process is simple, energy-efficient, and reproducible, facilitating industrial-scale mass production. In summary, this invention provides an electric mosquito repellent liquid solution that is environmentally friendly, has uniform evaporation, is low in irritation, and is easy to prepare, and has broad market application prospects. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0015] Figure 1 This is a flowchart of the preparation method of the environmentally friendly electric mosquito repellent liquid using bio-based solvents according to the present invention. Detailed Implementation

[0016] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0017] This invention provides an environmentally friendly electric mosquito repellent liquid using a bio-based solvent, comprising the following components by weight percentage: Bio-based solvents: 80%–85%; Active ingredient: 0.8%–1.9%; Antioxidant: 0.05%–0.2%; Stabilizer: 0.1%–0.5%; The balance is C1-C3 alcohols; The active ingredient is one or both of chlorfluazuron and tetrafluazuron.

[0018] The mass percentage of the chlorpyrifos is 0.5% to 1.2%.

[0019] The mass percentage of the tetrafluoromethrin is 0.3% to 0.7%.

[0020] The bio-based solvent is a compound mixture of dipropylene glycol methyl ether and ethyl lactate, with a mass ratio of 60-80:20-40.

[0021] The antioxidant is tocopherol, butylated hydroxyanisole, or butylated hydroxytoluene; the stabilizer is epoxidized soybean oil or epoxidized linseed oil.

[0022] In this specific embodiment, the mass percentage of chlorpyrifos can be 0.8%, 0.9%, 1.0%, or 1.2%, and the mass percentage of tetrafluoromethrin can be 0.62%. When chlorpyrifos and tetrafluoromethrin are used in combination, the sum of their mass percentages is preferably 0.8% to 1.9%. As a more specific example, chlorpyrifos is 0.8% and tetrafluoromethrin is 0.62%, with a sum of 1.42%. The C1-C3 alcohol is preferably anhydrous ethanol to enhance the miscibility of the system and improve the wettability of the mandrel. The bio-based solvent can also be selected from methyl lactate, methyl soybean oil, and palm oil. A compound system of one or more of palm oil methyl ester, propylene glycol methyl ether, dipropylene glycol methyl ether, or dipropylene glycol dimethyl ether with ethyl lactate, wherein the mass ratio of dipropylene glycol methyl ether to ethyl lactate is preferably 65-75:25-35; the antioxidant may also be rosemary extract or tea polyphenols, and the stabilizer may also be epoxy fatty acid methyl ester, wherein the mass ratio of the antioxidant to the stabilizer is preferably 1:2-1:5, to synergistically inhibit the oxidative deterioration of bio-based solvents under long-term heating; the active ingredient may also contain no more than 0.3% of a synergist, wherein the synergist is a synergist ether or octachlorodipropyl ether, to enhance the mosquito repellent effect without increasing the amount of pyrethroid.

[0023] The evaporation rate of the bio-based solvent compound system of the present invention is more matched with the evaporation characteristics of the active ingredient, so that the release of the active ingredient is maintained between 85% and 115% of the initial value throughout the entire use cycle; the synergistic effect of antioxidants and stabilizers reduces the decomposition rate of the active ingredient after heat storage to below 1.5%; the preferred C1-C3 alcohol further reduces the viscosity of the formulation, ensuring the long-lasting and smooth capillary action of the mandrel; the addition of compound synergists can maintain excellent knockdown effect even when the total amount of active ingredient is at the lower limit of 0.8%, thus broadening the applicable concentration range of the formulation.

[0024] On the other hand, the present invention also includes a preparation method, comprising the following steps:

[0025] S1: Dissolve the active ingredient in the formulation with a portion of the bio-based solvent at 20℃~40℃ to obtain an active pre-solution.

[0026] Specifically, the amount of the bio-based solvent used is 10% to 30% of the total amount of bio-based solvent.

[0027] In this specific embodiment, the stirring speed for dissolving in step S1 is 100-300 rpm. The dissolution time is 10-20 minutes at rpm. The preferred temperature range of 20℃-40℃ is 25℃-35℃, at which temperature the solubility of chlorpyrifos and tetrafluoromethrin is highest and there is no risk of decomposition. When the active ingredient contains tetrafluoromethrin and its mass percentage is close to 0.7%, the preferred temperature is 35℃-40℃ to accelerate its complete dissolution. The amount of the bio-based solvent is 10%-30% of the total amount of bio-based solvent, and more preferably 15%-25%. This ratio can ensure that the active ingredient is fully dissolved to form a clear pre-solution, and avoid local supersaturation and precipitation of the active ingredient in the subsequent main mixture due to excessive solvent. The bio-based solvent can be entirely dipropylene glycol methyl ether, entirely ethyl lactate, or a mixture of both. Dipropylene glycol methyl ether is preferred as the pre-dissolving solvent because its dissolving ability for pyrethroid active ingredients is better than that of ethyl lactate, which can shorten the dissolution time to less than 10 minutes.

[0028] S2: Then mix the remaining bio-based solvent with antioxidants and stabilizers, stir well to obtain the main mixture.

[0029] In this specific embodiment, the stirring speed in step S2 is 150–400 rpm. The stirring time is 5-15 minutes at rpm, and the mixing temperature is 20℃-30℃. The remaining bio-based solvent is the total amount of bio-based solvent minus the portion used in step S1. The preferred mixing order of the remaining bio-based solvent with the antioxidant and stabilizer is as follows: first, add the remaining bio-based solvent to the reactor and start stirring, then add the stabilizer and antioxidant in sequence, with the stabilizer added first to facilitate its full dispersion in the solvent, followed by the antioxidant. When the antioxidant is tocopherol or butylated hydroxyanisole, it can be dissolved in a small amount of the C1-C3 alcohol (such as anhydrous ethanol) before being added to improve the uniformity of dispersion. When the stabilizer is epoxidized soybean oil, it can be added directly without pretreatment. The mixing endpoint of the main mixture is that the system is uniform and transparent, without layering or flocculent matter. The mixing temperature of step S2 is further preferably 25℃±2℃, at which temperature the compatibility between the stabilizer and the bio-based solvent is optimal, which can avoid the precipitation of the stabilizer at low temperature or the oxidation and inactivation of the antioxidant at high temperature.

[0030] S3: Add the active pre-solution to the main mixture while stirring, and homogenize for 15-30 minutes to obtain a homogeneous mixture.

[0031] Specifically, the homogenization rotation speed is 300–600 rpm.

[0032] In this specific embodiment, in step S3, when adding the active pre-solution to the main mixture, it is added slowly in a fine stream or by mist spraying over a period of 5-10 minutes to avoid local oversaturation leading to the precipitation of effective components. During the addition process, the stirring speed is maintained at 200-300 rpm. After all the active pre-solution has been added, the stirring speed is increased to 300-600 rpm for homogenization, preferably 400-500 rpm. The homogenization temperature is 20℃-40℃, and the homogenization time is 15-30 minutes, until the system is clear, transparent, homogeneous, and stable, with no visible oil droplets or suspended matter. When the total content of effective components in the formulation is close to 1.9%, the homogenization time is preferably extended to 25-30 minutes, and the stirring speed is appropriately increased to 500-600 rpm to ensure complete dispersion of high-concentration effective components. The homogenization process can be assisted by a high-shear emulsifier with a shear speed of 2000-4000 rpm. The process should be performed at rpm for 1 to 3 minutes, intermittently, to avoid overheating.

[0033] S4: Degas the homogeneous mixture and then let it stand for aging.

[0034] In this specific embodiment, the degassing treatment in step S4 preferably uses vacuum degassing with a vacuum degree of -0.06 to -0.09 MPa and a degassing time of 10 to 20 minutes to effectively remove dissolved gases and microbubbles from the homogeneous mixture, preventing bubble precipitation during storage or use after filling, which could lead to interruption of mandrel liquid absorption or fluctuations in evaporation rate. The temperature of the mixture during degassing treatment is maintained at 20°C to 30°C. Too high a temperature may result in the loss of C1-C3 alcohols through evaporation, while too low a temperature will reduce degassing efficiency. The standing curing involves transferring the degassed mixture to a sealed container and letting it stand at room temperature for 12 to 24 hours. During this process, the molecules of each component further associate through van der Waals forces and hydrogen bonds, forming a more stable solvent-active ingredient-auxiliary compound structure, thereby making the evaporation rate more stable during subsequent use. The container should be sealed during curing to prevent solvent evaporation and foreign matter from falling in.

[0035] S5: After aging, filter the solution and fill the homogeneous mixture into an electric mosquito repellent liquid bottle, then seal it to obtain the finished product.

[0036] In this specific embodiment, the filtration in step S5 uses a 200-400 mesh sieve or a 5-10 micrometer filter bag, preferably a 400 mesh sieve or a 5 micrometer filter bag, to remove trace amounts of insoluble matter or gel-like impurities that may be generated during the curing process, thus avoiding clogging the micropores of the electric mosquito repellent liquid core. The filtration operation is carried out under normal pressure or slightly positive pressure, and the filtration temperature is consistent with room temperature. During filling, the filtered liquid is injected into a special bottle of electric mosquito repellent liquid pre-filled with the core according to predetermined specifications (such as 45mL, 60mL, 90mL). The core can be made of high-density wood, plastic, or ceramic, preferably high-density wood, as its capillary effect is most compatible with the bio-based solvent system of this invention. The filling accuracy is controlled within ±1%, and the bottle is immediately sealed with aluminum foil or a sealing gasket after filling to prevent solvent evaporation and loss of active ingredients during storage.

[0037] Examples 1-3: Electric mosquito repellent liquid was prepared according to the proportions and preparation method described in this invention. The specific formulas are shown in Table 1.

[0038] Comparative Example 1: A conventional petroleum-based solvent (C13 isoalkane) was used instead of a bio-based solvent, and the remaining components were the same as in Example 2.

[0039] Comparative Example 2: No stabilizer (epoxidized soybean oil) was added, and the remaining components were the same as in Example 2.

[0040] Table 1. Composition of the formulations in the examples and comparative examples (mass percentage %) Chlorpyrimethanil 0.8 0.5 0.6 0.5 0.5 Tetrafluoromethrin 0.62 0.3 0.4 0.3 0.3 Dipropylene glycol methyl ether 56 58 44 - 52 Ethyl lactate 24 23.2 37.6 - 23.2 C13 isoalkanes - - - 75.2 - Tocopherol 0.1 0.2 0.05 0.2 0.2 Epoxidized soybean oil 0.3 0.3 0.5 0.3 - Anhydrous ethanol Supplement to 100 Supplement to 100 Supplement to 100 Supplement to 100 Supplement to 100 total 100 100 100 100 100

[0041] Evaporation rate uniformity test: Methods: A standard electric mosquito repellent liquid heater was used for continuous heating for 360 hours. The amount of liquid remaining on the heating element was measured every 24 hours. The percentage of the cumulative volatilization of the active ingredients (chlorfenapyr + tetrafluoromethrin) relative to the initial total amount was calculated to assess the uniformity of volatilization. The maximum fluctuation range of the hourly volatilization rate of the active ingredients over 360 hours (relative to the average hourly volatilization rate) was used as the evaluation index.

[0042] Results: See Table 2.

[0043] Active ingredient decomposition rate test: Methods: Each sample was stored in a 54℃ constant temperature chamber for 14 days (accelerated heat storage test). The total content of chlorpyrifos and tetrafluoromethrin in the samples before and after heat storage was determined by gas chromatography, and the decomposition rate of the active ingredients was calculated. Results: See Table 2.

[0044] Mosquito repellent efficacy test (KT50 value):

[0045] Methods: Using Culex pipiens pallens as the test insect, the median knockdown time (KT50) of each sample was determined. Results: See Table 2.

[0046] Sensory stimulation assessment:

[0047] Methods: Thirty healthy volunteers (including 10 who reported a history of respiratory sensitivities) were selected. In a 30 m³ closed room, each sample was heated for 8 hours. Participants rated the odor intensity (1-no odor, 2-mild, 3-obvious, 4-strong, 5-unbearable) and respiratory irritation (1-no irritation, 2-mild, 3-moderate, 4-severe, 5-unbearable). The results were averaged. Results: See Table 2.

[0048] Table 2 Summary of Performance Test Results Maximum fluctuation range of evaporation rate (%) ±6.8 ±7.2 ±8.1 ±15.6 ±12.4 Decomposition rate of effective components after thermal storage (%) 1.1 0.9 1.3 2.8 4.2 KT50 value (minutes) 6.2 7.5 6.8 8.9 7.8 Odor intensity rating 1.2 1.1 1.3 2.5 1.2 Respiratory irritation score (general population) 1.1 1.0 1.2 2.2 1.4 Respiratory irritation score (sensitive population) 1.3 1.2 1.4 3.1 1.8

[0049] The data in the table above shows that:

[0050] Uniformity of evaporation: During 360 hours of continuous use, the evaporation rate fluctuation of the active ingredient in the electric mosquito repellent liquids of Examples 1-3 of this invention was less than ±10% (maximum ±8.1%), which is far superior to Comparative Example 1 (±15.6%) using petroleum-based solvents and Comparative Example 2 (±12.4%) without stabilizers. This indicates that the bio-based solvent compound system used in this invention, combined with stabilizers, significantly improves the uniformity of evaporation and overcomes the defects of excessively rapid evaporation in the early stage and insufficient evaporation in the later stage.

[0051] Chemical stability: In Examples 1-3, the decomposition rate of the active ingredient after heat storage was less than 1.5%, with the lowest reaching 0.9%, while the decomposition rate of Comparative Example 1 was 2.8%, and the decomposition rate of Comparative Example 2 reached 4.2% due to the lack of a stabilizer. This demonstrates that the antioxidant and stabilizer of the present invention work synergistically to effectively inhibit the oxidative deterioration of the active ingredient and bio-based solvent under long-term heating or storage conditions.

[0052] Mosquito repellent effect: The KT50 values ​​of Examples 1-3 were all within 7.5 minutes, which was better than Comparative Example 1 (8.9 minutes) and Comparative Example 2 (7.8 minutes), proving that the formulation of the present invention still maintains excellent knockdown effect under the premise of lower irritation.

[0053] Sensory and Safety: Examples 1-3 scored significantly lower than Comparative Example 1 in terms of odor intensity and respiratory irritation (especially for sensitive individuals), and were superior to Comparative Example 2 without stabilizers. This confirms that the bio-based solvents and formulations used in this invention are gentler and safer for users (including infants, the elderly, and those with allergies), avoiding the irritating byproducts that may be generated when heating petroleum-based solvents.

[0054] In summary, the environmentally friendly electric mosquito repellent liquid with bio-based solvents of the present invention has achieved significant progress in terms of evaporation uniformity, chemical stability, mosquito repellent effect, and user comfort.

[0055] The above-disclosed embodiments are merely one or more preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art can understand that all or part of the processes for implementing the above embodiments and equivalent changes made in accordance with the claims of this application still fall within the scope of this application.

Claims

1. An environmentally friendly electric mosquito repellent liquid using a bio-based solvent, characterized in that, By mass percentage, it includes the following components: Bio-based solvents: 80%–85%; Active ingredient: 0.8%–1.9%; Antioxidant: 0.05%–0.2%; Stabilizer: 0.1%–0.5%; The balance is C1-C3 alcohols; The active ingredient is one or both of chlorfluazuron and tetrafluazuron.

2. The environmentally friendly electric mosquito repellent liquid with a bio-based solvent as described in claim 1, characterized in that, The mass percentage of the chlorpyrifos is 0.5% to 1.2%.

3. The environmentally friendly electric mosquito repellent liquid with a bio-based solvent as described in claim 1, characterized in that, The mass percentage of the tetrafluoromethrin is 0.3% to 0.7%.

4. The environmentally friendly electric mosquito repellent liquid with a bio-based solvent as described in claim 1, characterized in that, The bio-based solvent is selected from one or more of the following: lactic acid esters, vegetable oil methyl esters, and bio-based glycol ethers.

5. The environmentally friendly electric mosquito repellent liquid with a bio-based solvent as described in claim 4, characterized in that, The bio-based solvent is a compound mixture of dipropylene glycol methyl ether and ethyl lactate, with a mass ratio of 60-80:20-40.

6. The environmentally friendly electric mosquito repellent liquid with a bio-based solvent as described in claim 1, characterized in that, The antioxidant is tocopherol, butylated hydroxyanisole, or butylated hydroxytoluene; the stabilizer is epoxidized soybean oil or epoxidized linseed oil.

7. A process for the preparation of an eco-friendly electric mosquito repellent liquid incense with bio-based solvent as claimed in any of claims 1-6, wherein, Includes the following steps: The active ingredient in the formulation was dissolved with a portion of the bio-based solvent at 20℃~40℃ to obtain an active pre-solution; Then, the remaining bio-based solvent is mixed with antioxidants and stabilizers, and stirred until homogeneous to obtain the main mixture; Then, the active pre-solution is added to the main mixture under stirring, and homogenization is carried out for 15-30 minutes to obtain a homogeneous mixture; The homogeneous mixture is degassed and then allowed to stand for aging. After aging and filtration, the homogeneous mixture is filled into electric mosquito repellent liquid bottles and sealed to obtain the finished product.

8. The preparation method according to claim 7, characterized in that, The amount of the bio-based solvent used is 10% to 30% of the total amount of bio-based solvent; the homogenization speed is 300 to 600 rpm.

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