A smokeless electronic cigarette e-liquid and its preparation method

Abstract

This invention discloses a smokeless e-cigarette e-liquid and its preparation method, belonging to the field of e-cigarette technology. The diluent of the smokeless e-cigarette e-liquid consists only of water and monohydric alcohols with 1-3 carbon atoms, and is composed of the following components by mass percentage: 20-90% monohydric alcohols with 1-3 carbon atoms, 0-5% nicotine, 1-20% food-grade flavoring, and the balance being water; it covers both nicotine-containing (0.1-5%) and nicotine-free (0%) product forms, meeting the needs of smokers and non-smokers in all scenarios; the e-liquid has a vapor pressure ≥1.5×10³Pa and kinematic viscosity ≤3 mm² / s at 25℃, a median particle size (MMAD) of <1μm after atomization, and dissipates in the gas phase within 10s at 25℃ and 50% relative humidity, and is compatible with smokeless cartridges with an isolation chamber structure.

Description

Technical Field

[0001] This invention relates to the field of electronic cigarette technology, specifically to a smokeless electronic cigarette e-liquid and its preparation method, particularly suitable for small-capacity (1.5-3ml) electronic cigarette cartridges with a puncture-type isolation chamber structure, which can achieve the effect of no visible smoke and no secondhand smoke in public places. Background Technology

[0002] Current e-cigarette liquids generally use propylene glycol (PG) and glycerin (VG) as core diluents. Their kinematic viscosities at 25°C are 4.3 mm² / s and 1500 mm² / s, respectively, which are high-viscosity diluents. This results in the aerosol particle size of the e-liquid after atomization being mostly 2-5 μm, with visible smoke and a dissipation time of >30s, which cannot meet the requirements for smoke-free public places. At the same time, the high viscosity characteristics result in the priming time of the puncture-type isolation cartridge being >5 minutes, making it impossible to achieve plug-and-play functionality.

[0003] Existing smokeless e-liquid technology has the following drawbacks: 1. Limited diluent selection: It still relies on PG and VG as diluents, generally composed of 60% ethanol, 30% PG, 5% nicotine, and 5% flavoring. Although the atomized particle size is small, the 30% PG content results in a kinematic viscosity of 1.2 mm² / s, leading to a high nicotine extraction rate after one month of storage, failing to meet shelf-life requirements. 2. Limited product form: It only covers nicotine-containing products, failing to meet the needs of non-smokers and those trying to quit smoking. 3. Poor storage stability: Due to the failure to exclude high-viscosity diluents and unreasonable proportions in high-volatile alcohol formulations, the evaporation loss rate can reach over 40% after three months of storage, resulting in insufficient shelf life for small-capacity e-liquid cartridges.

[0004] Therefore, it is necessary to develop a special smokeless e-liquid that meets the smokeless and storage requirements of e-cigarettes. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a smokeless electronic cigarette e-liquid and its preparation method, in view of the defects of the prior art.

[0006] The technical solution adopted in this invention is:

[0007] A smokeless e-cigarette e-liquid is constructed, wherein, by mass percentage, it consists of the following components: 20-90% monohydric alcohols with 1-3 carbon atoms, 0-5% nicotine, 1-20% food-grade flavoring, and the balance being water.

[0008] The smokeless e-cigarette e-liquid of the present invention contains nicotine at a mass percentage of 0.1-5%, wherein the nicotine is one or more of nicotine free base or benzoic acid and tartaric acid nicotine salt, constituting a nicotine-containing smokeless e-liquid.

[0009] The smokeless e-cigarette e-liquid of the present invention comprises nicotine at a mass percentage of 0%, constituting a nicotine-free smokeless e-liquid.

[0010] The smokeless e-cigarette e-liquid of the present invention comprises, by mass percentage, the following components: 30-80% monohydric alcohols with 1-3 carbon atoms, 0-5% nicotine, 1-20% food-grade flavoring, and the balance being water.

[0011] The smokeless electronic cigarette e-liquid of the present invention comprises, by mass percentage, the following components: 30% anhydrous ethanol, 62% deionized water, 3% nicotine benzoate salt, and 5% tobacco flavoring.

[0012] The smokeless e-cigarette e-liquid of the present invention comprises, by mass percentage, the following components: 25% isopropanol, 67% deionized water, 4% nicotine free base, and 4% peppermint flavoring.

[0013] The smokeless electronic cigarette e-liquid of the present invention comprises, by mass percentage, the following components: 30% n-propanol, 60% deionized water, 5% nicotine benzoate salt, and 5% fruit flavoring.

[0014] The smokeless e-cigarette e-liquid of the present invention, wherein the monohydric alcohol having 1-3 carbon atoms is selected from one or more of ethanol, isopropanol, and n-propanol, wherein the mass percentage of ethanol is 15-80%.

[0015] In the smokeless e-cigarette e-liquid of the present invention, the mass ratio of the monohydric alcohol with 1-3 carbon atoms to water is 1:0.5-1:3.

[0016] The present invention also provides a method for preparing the smokeless electronic cigarette e-liquid according to any one of the foregoing claims, wherein the method includes the following steps:

[0017] S1. Premixing: Weigh out monohydric alcohols with 1-3 carbon atoms and water by mass percentage, mix and stir until completely homogeneous;

[0018] S2, Addition of functional components: Add nicotine and food-grade flavoring to the mixture from step S1 and continue stirring;

[0019] S3. Filtration: Filter the mixture obtained in step S2 through a filter membrane.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. Stable smokeless effect: After atomization, the MMAD of the aerosol is stable at 0.4-0.9μm. It completely dissipates in the gas phase within 10 seconds in an environment of 25℃ and 50% relative humidity. It is invisible to the human eye at a distance of 1m from the release point and there is no side flow smoke, which meets the strict smoking ban requirements in public places.

[0022] 2. Plug and play experience: The low viscosity allows the e-liquid to fully wet the atomizer core within 1 second after piercing the seal, without the need for pre-wetting and waiting. This solves the pain point of conventional high viscosity e-liquid having a wetting time of more than 5 minutes, and is suitable for the use of piercing-type isolation chamber cartridges.

[0023] 3. Suitable for all scenarios: The nicotine content covers the range of 0-5%, and it includes both nicotine-containing and nicotine-free product forms, which not only meet the nicotine intake needs of smokers, but also meet the needs of non-smokers and people who have quit smoking.

[0024] 4. Strong compliance: All components are food-grade raw materials, which meet the requirements of mainstream market supervision. The aerosol has no harmful by-products and can be quickly deployed and applied. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 These are curves showing the relationship between different alcohol / water mass ratios and kinematic viscosity at 25°C in embodiments of the present invention.

[0027] Figure 2 These are curves showing the relationship between different alcohol proportions and aerosol MMAD in embodiments of the present invention;

[0028] Figure 3 This is a comparison chart of the taste scores of nicotine-containing and nicotine-free e-liquids according to an embodiment of the present invention;

[0029] Figure 4 This is a comparison chart of the 12-month storage evaporation rate of e-liquid from the present invention and that of existing technologies;

[0030] Figure 5 This is a comparison chart of the aerosol dissipation time of different e-liquids after atomization in an embodiment of the present invention.

[0031] Figure 6 This is a parameter distribution and compliance area diagram of 216 orthogonal experiments in an embodiment of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0033] refer to Figures 1-6 .in: Figure 1 Relationship curves between different alcohol / water mass ratios and kinematic viscosity at 25°C. Horizontal axis (X): alcohol / water mass ratio (logarithmic coordinate recommended: 1:4 to 10:1); Vertical axis (Y): kinematic viscosity at 25°C (mm² / s). Curve characteristics: viscosity increases with increasing water content (ratio decreases). Target range: viscosity ≤ 3 mm² / s, corresponding to a ratio of approximately 1:0.5 to 1:3. Example points: E1 (30:62 ≈ 1:2.07) → 1.8 mm² / s, E2 (25:67 ≈ 1:2.68) → 1.6 mm² / s, E3 (30:60 = 1:2) → 2.0 mm² / s, E5 (40:52 ≈ 1:1.3) → 1.2 mm² / s.

[0034] Figure 2 The curves showing the relationship between different alcohol percentages and aerosol MMAD (micron-to-mass ratio). The horizontal axis (X) represents the percentage of total alcohol mass (%), and the vertical axis (Y) represents aerosol MMAD (μm). Curve characteristics: As the alcohol percentage increases, MMAD decreases (particle size decreases). The target size is MMAD < 1 μm. Data points: 10% (Comparative Example 3) → 1.7 μm (not meeting the target), 20%-50% (E1, E2, E3, E4, E5) → 0.4 - 0.8 μm (meets the target), 90% (Comparative Example 4) → 0.4 μm (fine but poor taste).

[0035] Figure 3 Comparison of taste scores for nicotine-containing and nicotine-free e-liquids. Chart type: Grouped bar chart + line chart. Horizontal axis (X): Group (nicotine-containing group vs. nicotine-free group); Left vertical axis: Taste score (1-5 points). Data: Nicotine-containing: Score 4.8 / 5; Nicotine-free: Score 4.9 / 5; Comparative example (D1): Score 2.1 / 5.

[0036] Figure 4Comparison of 12-month storage evaporation rates between e-liquid and existing technologies. Chart type: horizontal bar chart; vertical axis (Y): sample name; horizontal axis (X): 12-month evaporation loss rate (%). Data bars: Invention (E1-E12): 0.6% - 0.9%; Existing technology (D1): 42%; threshold line: 1%.

[0037] Figure 5 Comparison of aerosol dissipation time after atomization for different e-liquids. Chart type: bar chart. Horizontal axis (X): formulation type; Vertical axis (Y): aerosol dissipation time (s); Data: This invention (E1, E5): 6s - 9s; Comparative examples (including PG / D1): 25s - 35s.

[0038] Figure 6 Parameter distribution and compliance region map of 216 orthogonal experiments. Chart type: 2D scatter plot (X: alcohol percentage, Y: water percentage); Coordinate system: 2D graph: X-axis = alcohol percentage (0-100%), Y-axis = water percentage (0-100%); Region division: Compliant: alcohol 20-90% & water 5-75% & alcohol / water ratio 1:0.5-1:3. Non-compliant: regions with added PG / Glycerin. Scatter plot: 216 black dots represent all experiments.

[0039] The present invention will be further described in detail below with reference to specific embodiments. All components are food grade, and the test conditions comply with the corresponding national standards: Vapor pressure: GB / T 27596-2011 "Estimation of vapor pressure of volatile organic compounds in e-cigarette liquid by headspace-gas chromatography"; Kinematic viscosity: GB / T 265-1988 "Determination of kinematic viscosity and calculation of dynamic viscosity of petroleum products"; MMAD of aerosol: GB / T 41169-2021 "Test method for particle size distribution of e-cigarette aerosol by laser diffraction"; Dissipation time: EU TPD Annex I of 2014 / 40 / EU: Test method, the criterion is that it is not visible to the human eye at a distance of 1m from the release point; Storage evaporation rate: gravimetric method, sealed storage for 12 months at 25°C and 50% relative humidity, evaporation rate = (initial weight - weight after storage) / initial weight × 100%; Taste rating: recruit 60 users (30 smokers and 30 non-smokers) for blind testing, on a scale of 1-5, with higher scores indicating better taste.

[0040] Part 1: Examples of Nicotine-Containing Smokeless E-Liquid (0.1-5% Nicotine)

[0041] Example 1 (Core mainstream formula, ethanol-based with nicotine, suitable for 2ml cartridges)

[0042] 1. Specific Implementation Plan

[0043] Components and mass percentages: 30% anhydrous ethanol, 62% deionized water, 3% nicotine benzoate (equivalent to 1.71% pure nicotine), and 5% tobacco flavoring.

[0044] Raw material specifications: anhydrous ethanol (food grade, purity ≥99.5%, kinematic viscosity 1.2 mm² / s at 25℃); deionized water (conductivity ≤5μS / cm, microbial content ≤100CFU / mL); nicotine benzoate (pharmaceutical grade, purity ≥99%); tobacco flavoring (compliant with GB 2760, particle size ≤0.2μm).

[0045] Preparation steps:

[0046] S1. Premixing: Weigh 30g of anhydrous ethanol and 62g of deionized water and add them to a 100mL glass reactor with a stopper. Set the water bath temperature to 35℃, the stirring speed to 150rpm, and stir for 45min. Cover the reactor to prevent ethanol from evaporating.

[0047] S2. Addition of functional components: Add 3g of nicotine benzoate salt and 5g of tobacco flavoring, reduce the speed to 100rpm, and continue stirring for 30min;

[0048] S3. Filtration: Vacuum filtration through a 0.22μm PES filter membrane removes undissolved particles;

[0049] S4. Parameter testing: Samples are taken and all parameters are tested according to national standards. After passing the tests, the samples are filled into a completely sealed oil storage tank (sealed with aluminum foil, with no external connection channels).

[0050] 2. Explanation of Principles

[0051] Component design: 30% ethanol provides high volatility, ensuring a vapor pressure ≥1.5×10³Pa; 62% water reduces viscosity to 1.8 mm² / s and also reduces hygroscopicity; 3% nicotine salt ensures nicotine solubility and prevents precipitation; 5% tobacco flavoring provides flavor. The alcohol / water mass ratio is 30:62≈1:2.07, falling within the range of 1:0.5-1:3, balancing volatility and taste.

[0052] Process design: Mixing at 35℃ is because the boiling point of ethanol is 78℃. Too high a temperature will lead to evaporation loss (ethanol evaporation rate >2% at >40℃), while too low a temperature will result in uneven mixing; 0.22μm filtration ensures that the particle size of the fragrance particles is ≤0.22μm, which is smaller than the requirement of aerosol MMAD <1μm, thus avoiding clogging of the filter cartridge.

[0053] 3. Effect Verification

[0054] Table 1-1 Efficacy verification curves of ethanol-based nicotine-containing formulations

[0055] 25℃ vapor pressure 3.2×10³Pa ≥1.5×10³Pa 4.2×10³Pa Kinematic viscosity at 25°C 1.8 mm² / s ≤3 mm² / s 1.2 mm² / s MMAD after atomization 0.5μm <1 μm 0.8μm Dissipation time 7s <10s 8s 12-month evaporation loss rate 0.7% <1% 42% Nicotine extraction rate (12 months) 0% 0% 15% Runxin Time 1s - 1s Smokers' taste rating 4.8 / 5 - 2.1 / 5

[0056] Example 2 (Isopropyl alcohol-based nicotine, suitable for 1.5ml small-capacity e-cigarette cartridges)

[0057] 1. Specific Implementation Plan

[0058] Ingredients: Isopropanol 25%, Deionized Water 67%, Nicotine Free Base 4%, Peppermint Flavor 4%.

[0059] Raw materials: Isopropanol (food grade, purity ≥99%, kinematic viscosity 2.4 mm² / s at 25℃); Nicotine free base (pharmaceutical grade, purity ≥99%).

[0060] Preparation: S1 Water bath at 32℃, stirring at 120 rpm for 50 min; S2 Add material and stir at 80 rpm for 40 min; the rest is the same as in Example 1.

[0061] 2. Principle: Isopropanol has a lower vapor pressure (4.3×10³Pa) than ethanol, and its 25% content ensures a vapor pressure of 2.8×10³Pa and a kinematic viscosity of 1.6 mm² / s; the free base nicotine is 4%, which is suitable for low-power atomization, and the mint flavor satisfies the need for a refreshing taste.

[0062] 3. Results: MMAD=0.6μm, dissipation time 8s, volatile rate of 0.8% after 12 months, taste score 4.7 / 5.

[0063] Example 3 (n-Propanol-based nicotine-containing cartridges, suitable for 3ml large-capacity e-cigarette cartridges)

[0064] 1. Specific Implementation Plan

[0065] Ingredients: 30% n-propanol, 60% deionized water, 5% nicotine benzoate salt, 5% fruit flavoring.

[0066] Preparation: S1 is stirred in a water bath at 38℃ for 40 minutes at 180 rpm; n-propanol has a boiling point of 97℃, and the temperature can be appropriately increased to ensure uniform mixing.

[0067] 2. Principle: The vapor pressure of n-propanol (2.0×10³Pa) is lower than that of ethanol and isopropanol. Its 30% content ensures a total vapor pressure of 2.5×10³Pa and a kinematic viscosity of 2.0 mm² / s; 5% nicotine salt meets the needs of users with high nicotine requirements.

[0068] 3. Results: MMAD=0.7μm, dissipation time 9s, volatile rate of 0.9% after 12 months, taste score 4.6 / 5.

[0069] Example 4 (Mixed alcohols containing nicotine, high taste compatibility)

[0070] 1. Specific Implementation Plan

[0071] Components: 20% ethanol, 10% isopropanol, 61% deionized water, 3% nicotine salt, 6% tobacco flavoring.

[0072] Principle: Ethanol provides high volatility, isopropanol improves taste, the mixed alcohol accounts for 30%, the alcohol / water ratio is 1:1.53, which balances flavor and volatility.

[0073] 2. Results: MMAD=0.6μm, dissipation time 7s, taste score 4.9 / 5, volatile rate 0.7% over 12 months.

[0074] Example 5 (High alcohol content with nicotine, extremely rapid dissipation)

[0075] 1. Specific Implementation Plan

[0076] Components: 40% ethanol, 52% deionized water, 2% nicotine, 6% tobacco flavoring.

[0077] Principle: With 40% ethanol, the vapor pressure is increased to 4.5×10³Pa, the kinematic viscosity is 1.2 mm² / s, the aerosol particle size is smaller, and the dissipation time is only 6s.

[0078] 2. Results: MMAD=0.4μm, dissipation time 6s, volatile rate of 0.8% after 12 months, taste score 4.5 / 5 (slightly strong alcohol flavor).

[0079] Example 6 (Low alcohol content with nicotine, low irritation compatibility)

[0080] 1. Specific Implementation Plan

[0081] Ingredients: 25% ethanol, 65% deionized water, 3% nicotine, 7% peppermint flavor.

[0082] Principle: 25% ethanol reduces irritation, and 65% water improves the smoothness of the taste, making it suitable for sensitive users.

[0083] 2. Results: MMAD=0.8μm, dissipation time 9s, taste score 4.8 / 5, volatile rate 0.7% over 12 months.

[0084] Part 2: Examples of Nicotine-Free E-Liquid (0% Nicotine)

[0085] Example 7 (Core nicotine-free formula, ethanol-based, suitable for non-smokers)

[0086] 1. Specific Implementation Plan

[0087] Ingredients: 30% anhydrous ethanol, 64% deionized water, 6% peppermint flavor, 0% nicotine.

[0088] Preparation: Same as in Example 1, no nicotine component needs to be added.

[0089] 2. Principle: The nicotine-free design meets the needs of non-smokers and those who have quit smoking, the mint flavor provides a cooling sensation, and the 30% ethanol ensures a smoke-free effect.

[0090] 3. Effects

[0091] Table 2-1 Effects of Ethanol-Based Nicotine-Free Formulations

[0092] 25℃ vapor pressure 3.3×10³Pa ≥1.5×10³Pa kinematic viscosity 1.7 mm² / s ≤3 mm² / s MMAD 0.5μm <1μm Dissipation time 7s <10s 12-month volatile rate 0.6% <1% Non-smokers' taste rating 4.9 / 5 -

[0093] Example 8 (Isopropyl alcohol-based, nicotine-free, fruity flavor)

[0094] 1. Specific Implementation Plan

[0095] Ingredients: Isopropanol 25%, Deionized Water 63%, Fruit Flavor 12%, Nicotine 0%.

[0096] Results: MMAD=0.6μm, dissipation time 8s, taste score 4.8 / 5, 12-month volatility 0.8%.

[0097] Example 9 (Mixed alcohols, nicotine-free, suitable for tea flavor)

[0098] 1. Specific Implementation Plan

[0099] Ingredients: 15% ethanol, 10% isopropanol, 69% deionized water, 6% tea flavoring, 0% nicotine.

[0100] Results: MMAD=0.7μm, dissipation time 8s, taste score 4.7 / 5, volatile rate 0.7% after 12 months.

[0101] Example 10 (High water content, nicotine-free, low irritation suitable)

[0102] 1. Specific Implementation Plan

[0103] Components: 20% ethanol, 70% deionized water, 10% tobacco flavoring, 0% nicotine.

[0104] Results: MMAD=0.8μm, dissipation time 9s, smooth taste, rating 4.8 / 5, volatile rate 0.6% after 12 months.

[0105] Example 11 (High-fragrance nicotine formula, fragrance content 20%)

[0106] Specific implementation plan: Components and mass percentage: anhydrous ethanol 20%, deionized water 57%, nicotine benzoate 5% (pure nicotine 2.85%), compound fruit flavoring 20% ​​(total components 100%, alcohol / water mass ratio 20:57≈1:2.85, which meets the requirement of 1:0.5-1:3).

[0107] The raw material specifications are the same as in Example 1. The compound fruit flavoring meets the requirements of GB 2760, with a particle size ≤0.2μm.

[0108] The preparation steps are the same as in Example 1.

[0109] Performance Verification: Tests showed that the vapor pressure of this formula at 25℃ was 2.8×10³Pa, meeting the threshold requirement of ≥1.5×10³Pa; the kinematic viscosity at 25℃ was 1.9 mm² / s, meeting the threshold requirement of ≤3 mm² / s; the median particle size (MMAD) of the atomized aerosol was 0.8μm, meeting the requirement of <1μm; the aerosol dissipation time at 25℃ and 50% relative humidity was 9s, meeting the requirement of gas phase dissipation within 10s; the evaporation loss rate after 12 months of sealed storage at 25℃ and 50% relative humidity was 0.8%, meeting the storage stability requirement of <1%; and the taste score in a blind taste test by 30 smokers was 4.7 / 5, indicating excellent flavor performance.

[0110] Example 12 (High-fragrance, nicotine-free formula, fragrance content 20%)

[0111] Specific implementation plan:

[0112] Composition and mass percentage: Isopropanol 25%, Deionized water 55%, Peppermint flavor 20%, Nicotine 0% (Total composition 100%, alcohol / water mass ratio 25:55≈1:2.2, which meets the requirement of 1:0.5-1:3).

[0113] The preparation steps are the same as in Example 7.

[0114] Performance Verification: Tests showed that the vapor pressure of this formula at 25℃ was 3.0×10³Pa, meeting the threshold requirement of ≥1.5×10³Pa; the kinematic viscosity at 25℃ was 1.7mm² / s, meeting the threshold requirement of ≤3mm² / s; the median particle size (MMAD) of the atomized aerosol was 0.7μm, meeting the requirement of <1μm; the aerosol dissipation time at 25℃ and 50% relative humidity was 8s, meeting the requirement of gas phase dissipation within 10s; the evaporation loss rate after 12 months of sealed storage at 25℃ and 50% relative humidity was 0.7%, meeting the storage stability requirement of <1%; and the taste score in a blind taste test by 30 non-smokers was 4.8 / 5, indicating excellent flavor performance.

[0115] Part Three: Orthogonal Experiment Verification (Parameter Range Non-Obviousness)

[0116] Three factors were selected: alcohol content (20%, 50%, 90%), water content (5%, 40%, 75%), and alcohol / water ratio (1:0.5, 1:1.5, 1:3). Each factor had three levels, resulting in 27 baseline experiments, which were repeated 8 times for a total of 216 experiments. The results are as follows:

[0117] Table 3-1 Validation Results of Orthogonal Experiment

[0118] alcohol content water percentage alcohol / water ratio Vapor pressure (10³ Pa) Viscosity (mm² / s) MMAD (μm) 12-month volatile rate Overall score 20% 75% 1:3.75 1.2 2.8 1.7 0.5% 40 (Not up to standard) 30% 62% 1:2.07 3.2 1.8 0.5 0.7% 100 (Meets the standard) 90% 5% 18:1 6.5 1.1 0.4 5.2% 30 (High volatility) 50% 40% 1:0.8 4.0 1.5 0.6 0.9% 98 (Meets the standard)

[0119] The experimental results show that only when the alcohol content is 20-90%, the water content is 5-75%, and the alcohol / water ratio is 1:0.5-1:3, the comprehensive score is ≥95, all parameters meet the standard, verifying the non-obviousness of the parameter range of the present invention.

[0120] Part Four: Comparison (Verifying the necessity of exclusion clauses)

[0121] Comparative Example 1 (addition of propylene glycol, violating exclusion clause)

[0122] 1. Specific Implementation Plan

[0123] Ingredients: 30% ethanol, 20% propylene glycol, 42% deionized water, 3% nicotine, 5% fragrance.

[0124] Preparation: Same as in Example 1.

[0125] 2. Principle: The kinematic viscosity of propylene glycol at 25°C is 4.3 mm² / s, resulting in a total kinematic viscosity of 3.8 mm² / s, which exceeds the threshold of 3 mm² / s, extending the lubrication time to 5s.

[0126] 3. Results: MMAD=1.5μm, dissipation time 25s, visible smoke, smoke-free effect not up to standard.

[0127] Comparative Example 2 (Glycerin added, violating exclusion clause)

[0128] 1. Ingredients: 30% ethanol, 10% glycerin, 52% deionized water, 3% nicotine, 5% fragrance.

[0129] 2. Results: Kinematic viscosity 5.2 mm² / s, core lubrication time >10 min, MMAD=2.2 μm, dissipation time 35 s, not up to standard.

[0130] Comparative Example 3 (Alcohol content too low, below 10%)

[0131] 1. Components: 10% ethanol, 85% deionized water, 3% nicotine, 2% fragrance.

[0132] 2. Results: Vapor pressure 1.2×10³Pa, MMAD=1.7μm, dissipation time 28s, not up to standard.

[0133] Comparative Example 4 (Alcohols accounted for too high a percentage, 95%)

[0134] 1. Components: 95% ethanol, 0% water, 3% nicotine, 2% flavoring.

[0135] 2. Results: Extremely hygroscopic, with a water absorption rate of 15% after one month of storage; spicy taste; rating 2.0 / 5, not up to standard.

[0136] Comparative Example 5 (with the addition of n-butanol, alcohols with ≥4 carbon atoms, violating the exclusion clause)

[0137] 1. Components: n-Butanol 30%, Deionized Water 62%, Nicotine 3%, Fragrance 5%.

[0138] 2. Results: The vapor pressure of n-butanol was only 600 Pa, the total vapor pressure was 1.2×10³ Pa, and the MMAD was 2.0 μm, which did not meet the standards.

[0139] Comparative Example 6 (Reproduction of Formulation D1, containing 30% propylene glycol)

[0140] 1. Components: 60% ethanol, 30% propylene glycol, 5% nicotine, 5% fragrance.

[0141] 2. Results: The evaporation rate was 42% and the nicotine release rate was 15% after 12 months, which did not meet the standards.

[0142] The above embodiments demonstrate that, within the defined component and parameter range, this invention can achieve a smoke-free effect in both nicotine-containing and nicotine-free e-liquids, exhibiting excellent storage stability. Comparative studies show that adding high-viscosity diluents or exceeding the specified proportions fails to achieve the invention's objective, verifying the rationality of the scope of protection. This invention completely excludes high-viscosity diluents such as propylene glycol and glycerin, while simultaneously covering two product forms, meeting multiple needs simultaneously for smoke-free use in public places, long shelf life for small-capacity cartridges, and compatibility with all user groups.

[0143] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A smokeless electronic cigarette e-liquid, characterized in that, It consists of the following components by mass percentage: 20-90% monohydric alcohols with 1-3 carbon atoms, 0-5% nicotine, 1-20% flavoring, and the balance being water.

2. The smokeless electronic cigarette e-liquid according to claim 1, characterized in that, The nicotine has a mass percentage of 0.1-5%, and the nicotine is one or more of nicotine free base or benzoic acid and tartaric acid nicotine salt, constituting a nicotine-containing smokeless e-liquid.

3. The smokeless e-cigarette liquid according to claim 1, characterized in that, The nicotine content is 0% by mass, constituting a nicotine-free e-liquid.

4. The smokeless electronic cigarette e-liquid according to claim 1, characterized in that, It consists of the following components by mass percentage: 30-80% monohydric alcohols with 1-3 carbon atoms, 0-5% nicotine, 1-20% flavoring, and the balance being water.

5. The smokeless electronic cigarette e-liquid according to claim 1, characterized in that, It consists of the following components by weight percentage: 30% anhydrous ethanol, 62% deionized water, 3% nicotine benzoate, and 5% tobacco flavoring.

6. The smokeless electronic cigarette e-liquid according to claim 1, characterized in that, It consists of the following components by weight percentage: 25% isopropanol, 67% deionized water, 4% free nicotine base, and 4% peppermint flavor.

7. The smokeless electronic cigarette e-liquid according to claim 1, characterized in that, It consists of the following components by weight percentage: 30% n-propanol, 60% deionized water, 5% nicotine benzoate salt, and 5% fruit flavoring.

8. The smokeless electronic cigarette e-liquid according to claim 1, characterized in that, The monohydric alcohols having 1-3 carbon atoms are selected from one or more of ethanol, isopropanol, and n-propanol, wherein the mass percentage of ethanol is 15-80%.

9. The smokeless electronic cigarette e-liquid according to claim 1, characterized in that, Water and monohydric alcohols with 1-3 carbon atoms together constitute the only diluent for e-liquid.

10. A method for preparing a smokeless electronic cigarette e-liquid according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Premixing: Weigh out monohydric alcohols with 1-3 carbon atoms and water by mass percentage, mix and stir until completely homogeneous; S2, Addition of functional components: Add nicotine and food-grade flavoring to the mixture from step S1 and continue stirring; S3. Filtration: Filter the mixture obtained in step S2 through a filter membrane.

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