A cool mint flavoured e-liquid formulation

Abstract

The application discloses a kind of refreshing mint electronic cigarette oil formula, the formula includes by weight percentage: glycerol 42%~48%, nicotine 4.5%~5.5%, benzoic acid 4.5%~5.5%, lactic acid 0.4%~0.6%, cooling agent WS-23 3.0%~4.0%, L-menthol 0.3%~1.5%, essence 0.1%~1.0%, the balance is propylene glycol;And the molar ratio of benzoic acid and lactic acid is 7~12:1, the weight ratio of WS-23 and L-menthol is 2~9:1, and the sum of the molar amount of the two is greater than the molar amount of nicotine.The application is fully protonated by mixing acid with specific ratio to reduce irritation, and the two cooling agents are used to produce stepwise cooling feeling, and the bitter aftertaste is effectively masked by essence recombination, suitable for the preparation of high-concentration nicotine salt electronic cigarette oil.

Description

Technical Field

[0001] This invention belongs to the field of electronic atomization technology, and in particular relates to a refreshing mint-flavored e-cigarette liquid formula. Background Technology

[0002] As a core consumable in electronic atomization devices, e-liquid's formulation directly impacts the user's inhalation experience and product safety. Currently, e-liquids typically use propylene glycol and glycerin as a composite solvent to provide suitable atomization viscosity and vapor volume; nicotine or nicotine salts as active ingredients to satisfy the user's physiological needs; and cooling agents and flavorings are added to improve sensory quality, depending on the product's positioning. Cooling agents primarily utilize amide-based cooling agents (such as WS-3 and WS-23) or naturally derived L-menthol, each with its own strengths: WS-23 offers a long-lasting cooling sensation without bitterness, but its onset is relatively slow; L-menthol provides an instant cooling impact, but the cooling effect fades quickly and is accompanied by bitterness and off-flavors at high concentrations. Regarding nicotine salt technology, existing technologies generally employ the formation of salts from organic acids and nicotine to reduce the irritation of free nicotine and improve inhalation smoothness. Commonly used organic acids include benzoic acid, lactic acid, and levulinic acid. To enrich flavor profiles, ethyl maltol is often added to flavoring systems as a sweetener and bitter masking agent, while vanillin and its derivatives are added as a creamy base. Some products also include monomeric flavorings such as isoamyl acetate and linalool to simulate specific flavors like fruit or tea. The selection and proportioning of these components constitute the core technology of e-liquid formulations, and the differences between different products mainly lie in the specific content and proportional relationships of each component.

[0003] However, the existing technologies still have the following shortcomings: First, in terms of nicotine salt acidification systems, existing formulations mostly use a single organic acid to form nicotine salts. Although this can reduce irritation to some extent, the protonation efficiency of a single acid for free nicotine is limited, and its ability to adjust the pH value of the system is limited. It is difficult to simultaneously meet the requirements of low irritation and smooth taste under high concentrations of nicotine, resulting in a noticeable "throat hit" or astringency in high-concentration nicotine salt e-liquids, affecting the user's inhalation comfort. Second, in terms of the compounding of cooling agents, the use of WS-23 and L-menthol in existing technologies is mostly a simple superposition, lacking systematic research and precise control on the synergistic ratio between the two. It is difficult to achieve both "rapid onset" and "long duration" of cooling sensation, and there are usually defects such as insufficient cooling sensation or excessively rapid cooling sensation decay. Thirdly, regarding the masking of bitterness in the flavoring system, the slight bitter aftertaste of high-concentration nicotine salts can easily interact unfavorably with the cooling sensation of mint. Current technologies rely on the conventional addition of single ethyl maltol or vanillin, which is insufficient in masking bitterness and affects the overall purity of the flavor. Fourthly, the ratio of propylene glycol to glycerin in current technologies is mostly set based on experience and has not been fully adapted and optimized for high-concentration mixed acid nicotine salt systems, making it difficult to simultaneously meet the multiple requirements of atomization efficiency, wicking rate, and flavor smoothness. These issues mean that current refreshing mint-flavored e-liquids still have significant room for improvement in terms of low irritation, layered cooling sensation, and flavor purity. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention provides a refreshing mint flavored e-cigarette oil formula, which solves the problems of low protonation efficiency of single acid nicotine salt, lack of synergistic control of cooling agents leading to a single cooling sensation, insufficient ability of flavoring to mask bitterness, and solvent ratio not adapted to high concentration salt system in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A refreshing mint-flavored e-cigarette liquid formula, comprising the following components by weight percentage: Glycerin 42%~48%; Nicotine content: 4.5%~5.5%; Benzoic acid 4.5%~5.5%; Lactic acid 0.4%~0.6%; Cooling agent WS-233.0%~4.0%; L-Menthol 0.3%~1.5%; Fragrance content: 0.1%~1.0%; The balance is propylene glycol; Furthermore, the molar ratio of benzoic acid to lactic acid is 7~12:1, the weight ratio of WS-23 to L-menthol is 2~9:1, and the sum of the molar amounts of benzoic acid and lactic acid is greater than the molar amount of nicotine.

[0006] Preferably, the weight ratio of propylene glycol to glycerin is 0.8 to 0.95:1.

[0007] Preferably, the weight ratio of nicotine to benzoic acid is 1:0.95~1.05.

[0008] Preferably, the flavoring comprises ethyl maltol and vanillin, and the weight ratio of ethyl maltol to vanillin is 2 to 3.5:1.

[0009] Preferably, the flavoring also contains isoamyl acetate, which is 0.05% to 0.15% by weight.

[0010] Preferably, the fragrance further contains vanillin propylene glycol acetal, with a weight percentage of 0.2% to 0.4%.

[0011] Preferably, the ratio of the sum of the molar amounts of benzoic acid and lactic acid to the molar amount of nicotine is 1.2 to 1.8:1.

[0012] Preferably, the total weight percentage of the flavoring is 0.2% to 0.8%.

[0013] Preferably, the weight ratio of WS-23 to L-menthol is 3~7:1.

[0014] Preferably, the nicotine content in the formula is 48~52 mg / ml.

[0015] The technical effects and advantages of the refreshing mint-flavored e-cigarette oil formula of this invention: 1. This invention constructs a mixed organic acid nicotine salt system by mixing benzoic acid and lactic acid in a specific molar ratio (7~12:1) and controlling the sum of their molar amounts to be greater than the molar amount of nicotine. Compared with the salt formation methods in the prior art that use benzoic acid alone or only neutralize it in equal molar amounts, the lactic acid in this invention acts as an auxiliary acid in synergy with benzoic acid, which can more fully protonate nicotine, reducing the amount of free nicotine residue to an extremely low level and effectively avoiding the strong irritation of the throat mucosa by free alkali. At the same time, the mixed use of the two acids can finely adjust the pH value of the system, making the e-liquid smoother and milder when inhaled, significantly improving the problem of "excessive throat hit" common in high-concentration nicotine salt e-liquids, greatly improving inhalation comfort while ensuring satisfaction, and overcoming the technical contradiction in the prior art of reducing nicotine concentration in pursuit of low irritation.

[0016] 2. This invention combines the cooling agent WS-23 with L-menthol in a specific weight ratio (2~9:1). L-menthol, with its rapid volatile properties, quickly activates cold receptors in the mouth and respiratory tract upon inhalation, producing an immediate cooling sensation. WS-23, as a long-lasting cooling agent, has a more stable molecular structure that binds to cold receptors, providing a sustained and prolonged cooling sensation. The synergistic effect of these two agents achieves a stepped cooling experience during inhalation—a burst of cooling sensation initially followed by a sustained and prolonged cooling sensation—overcoming the technical shortcomings of existing single-cooling agent systems, such as slow onset of cooling, limited cooling range, or rapid decline in cooling effect. This significantly enhances the sensory experience and consumer experience of e-cigarettes.

[0017] 3. This invention employs a specific weight ratio (2-3.5:1) of ethyl maltol and vanillin in the flavoring system. Ethyl maltol has the function of sweetening and masking bitterness, while vanillin provides a mild creamy base. The two produce a synergistic bitter-masking effect at a specific ratio, effectively masking the slight bitter aftertaste inherent in nicotine salts, making the minty coolness purer and clearer. Furthermore, characteristic flavoring monomers such as isoamyl acetate or vanillin propylene glycol acetal are added, which can respectively impart a fresh fruity base or a long-lasting, warm vanilla aroma to the e-liquid, enriching the aroma layers of the product without affecting the expression of the main minty coolness. Through the above flavoring compound system, the aroma of the refreshing minty e-liquid is fuller and more rounded, with a clean and comfortable aftertaste, and an overall pure and unadulterated flavor.

[0018] 4. This invention controls the weight ratio of propylene glycol to glycerin within the range of 0.8~0.95:1. This ratio ensures that the e-liquid has a suitable viscosity, matching the wicking rate and atomization efficiency of mainstream ceramic coil atomizers, avoiding problems such as poor wicking and coil burning caused by excessive viscosity, and also preventing leakage or mouth burning caused by excessively fine atomized droplets due to excessively low viscosity. Furthermore, the components in the formulation system of this invention have good compatibility, and show no stratification or precipitation even after long-term storage at room temperature and away from light, ensuring the product's stability during its shelf life and demonstrating good adaptability for industrial production.

[0019] 5. The weight percentages and key proportion parameters of each component in this invention exhibit synergistic correlation. When each parameter varies within its preferred range, the overall formulation maintains consistency in low throat irritation, a step-like cooling sensation, and a pure taste, demonstrating the excellent parameter robustness of this technical solution. Furthermore, by further optimizing the molar ratio of total acid to nicotine (1.2~1.8:1), the weight ratio of WS-23 to L-menthol (3~7:1), and the total flavor content (0.2%~0.8%), this invention can further optimize the reduction in irritation or the overall cooling effect based on the aforementioned beneficial effects. This provides ample technical guidance for fine-tuning the formulation in actual production, demonstrating good industrial operability and application value. Attached Figure Description

[0020] Figure 1 This is a flowchart of a refreshing mint-flavored e-cigarette oil formula proposed in this invention; Figure 2 This is a schematic diagram of the component composition of a refreshing mint-flavored e-cigarette oil formula proposed in this invention. Detailed Implementation

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

[0022] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include," "contain," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "includes..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0023] refer to Figure 1-2This invention provides a refreshing mint-flavored e-cigarette oil formula. The formula comprises the following components by weight percentage: 42%~48% glycerin, 4.5%~5.5% nicotine, 4.5%~5.5% benzoic acid, 0.4%~0.6% lactic acid, 3.0%~4.0% cooling agent WS-23, 0.3%~1.5% L-menthol, 0.1%~1.0% flavoring, and the balance being propylene glycol; wherein the molar ratio of benzoic acid to lactic acid is 7~12:1, the weight ratio of WS-23 to L-menthol is 2~9:1, and the sum of the molar amounts of benzoic acid and lactic acid is greater than the molar amount of nicotine. Through the above technical solution, the present invention achieves the following beneficial effects: First, benzoic acid and lactic acid are mixed in a specific molar ratio to form a mixed acid nicotine salt system, with the total acid content being excessive relative to nicotine, ensuring that nicotine is fully protonated, significantly reducing free alkali residue, and significantly reducing throat irritation, making the inhalation of high-concentration nicotine salt e-liquid smooth and gentle; Second, WS-23 and L-menthol are compounded in a specific weight ratio, utilizing the difference in their activation rate and duration of action of cold receptors to produce a stepped cooling effect of "instant coolness at the beginning and sustained coolness at the end". The cooling sensation is characterized by a short onset time and long duration, with rich layers of coolness. Third, the specific ratio of ethyl maltol and vanillin in the flavor system effectively masks the bitter aftertaste of nicotine salts, resulting in a pure and clear minty coolness. Adding characteristic flavor monomers such as isoamyl acetate or vanillin propylene glycol acetal further enriches the aroma without affecting the overall cooling sensation. Fourth, the weight ratio of propylene glycol to glycerin is controlled at 0.8~0.95:1, giving the e-liquid suitable atomization viscosity, adapting to the wicking and atomization efficiency of mainstream atomizers, and exhibiting good system stability. Based on this, further optimization of parameters such as the total acid to nicotine molar ratio of 1.2~1.8:1, the WS-23 to L-menthol weight ratio of 3~7:1, and the total flavor content of 0.2%~0.8% can further optimize the reduction in irritation or the overall cooling effect based on the aforementioned beneficial effects.

[0024] The preparation method of electronic e-liquid of the present invention: Weigh propylene glycol and glycerin according to the formula, mix and stir at room temperature, and heat to 40~50℃; add benzoic acid, lactic acid and nicotine in sequence, stir evenly to allow them to react fully to form nicotine salt; after the system cools to room temperature, add cooling agent WS-23, L-menthol and each flavor component in sequence, and continue stirring until completely dissolved; let the prepared e-liquid stand and age in a light-proof and airtight container for 12~24 hours, and filter through a 0.45μm microporous membrane to obtain the finished product. Example

[0025] Purpose of implementation: This embodiment aims to verify the overall sensory performance of the present invention when the core parameters (molar ratio of benzoic acid to lactic acid, molar ratio of total acid to nicotine, weight ratio of WS-23 to L-menthol, and weight ratio of ethyl maltol to vanillin) are all at moderate levels, thus providing an optimal benchmark formulation.

[0026] Ingredients: By weight percentage, glycerin 45.00%, propylene glycol 38.39%, nicotine 5.00%, benzoic acid 5.00%, lactic acid 0.50%, cooling agent WS-23 3.50%, L-menthol 1.45%, ethyl maltol 0.70%, vanillin 0.23%, vanillin propylene glycol acetal 0.23%, and the sum of the weight percentages of all components is 100%.

[0027] Implementation steps: Following the above preparation method, feed the materials in sequence, stir, heat, let stand and age for 18 hours, filter and collect the finished product.

[0028] Implementation Results: Calculations show that in this embodiment, the molar ratio of benzoic acid to lactic acid is 7.38:1, the molar ratio of total acid (benzoic acid + lactic acid) to nicotine is 1.51:1, the weight ratio of WS-23 to L-menthol is 2.41:1, the weight ratio of ethyl maltol to vanillin is 3.04:1, the weight ratio of propylene glycol to glycerin is 0.853:1, the weight ratio of nicotine to benzoic acid is 1:1, and the total weight percentage of flavoring is 1.16%. Sensory Evaluation Results: The VAS score for throat irritation (0-10 points, lower scores indicate less irritation) is 2.1; the cooling effect onset time is 0.4 seconds; and the cooling duration is 9.5 seconds, achieving a stepped cooling experience that is instantaneous at the beginning and lasts for a long time. Example

[0029] Purpose of implementation: This embodiment aims to verify the overall sensory performance of the formulation when the weight ratio of WS-23 to L-menthol is close to the upper limit (the upper end of the range of 2 to 9:1) and when isoamyl acetate is added to impart a fruity aroma base.

[0030] Ingredients: By weight percentage, glycerin 45.00%, propylene glycol 40.05%, nicotine 5.00%, benzoic acid 5.00%, lactic acid 0.50%, cooling agent WS-23 3.50%, L-menthol 0.40%, ethyl maltol 0.30%, vanillin 0.15%, isoamyl acetate 0.10%, and the sum of the weight percentages of all components is 100%.

[0031] Implementation steps: Following the above preparation method, feed the materials in sequence, stir, heat, let stand and age for 16 hours, filter and collect the finished product.

[0032] Implementation Results: Calculations showed that in this embodiment, the molar ratio of benzoic acid to lactic acid was 7.38:1, the molar ratio of total acid to nicotine was 1.51:1, the weight ratio of WS-23 to L-menthol was 8.75:1, the weight ratio of ethyl maltol to vanillin was 2.00:1, the weight ratio of propylene glycol to glycerin was 0.890:1, the weight ratio of nicotine to benzoic acid was 1:1, the total weight percentage of flavoring was 0.55%, and the content of isoamyl acetate was 0.10%. Sensory Evaluation Results: The VAS score for throat irritation was 2.3; the onset time of cooling effect was 0.5 seconds; and the duration of cooling effect was 8.2 seconds. This embodiment, while ensuring low irritation, imparts a fresh fruity aroma to the mint base through isoamyl acetate, resulting in a prominent refreshing sensation, verifying that stable performance can be maintained even with a relatively high proportion of cooling agents. Example

[0033] Purpose of implementation: This embodiment aims to verify the sensory performance when the weight ratio of WS-23 to L-menthol is in the optimal range (3~7:1) to determine the rationality of this optimal range.

[0034] Ingredients: By weight percentage, glycerin 44.00%, propylene glycol 40.60%, nicotine 5.00%, benzoic acid 5.00%, lactic acid 0.50%, cooling agent WS-23 3.60%, L-menthol 0.60%, ethyl maltol 0.50%, vanillin 0.20%, and the sum of the weight percentages of all components is 100%.

[0035] Implementation steps: Following the above preparation method, feed the materials in sequence, stir, heat, let stand and age for 20 hours, filter and collect the finished product.

[0036] Implementation Results: Calculations showed that in this embodiment, the molar ratio of benzoic acid to lactic acid was 7.38:1, the molar ratio of total acid to nicotine was 1.51:1, the weight ratio of WS-23 to L-menthol was 6.00:1, the weight ratio of ethyl maltol to vanillin was 2.50:1, the weight ratio of propylene glycol to glycerin was 0.923:1, and the total weight percentage of flavoring was 0.70%. Sensory Evaluation Results: The VAS score for throat irritation was 2.0; the onset time of cooling sensation was 0.35 seconds; and the duration of cooling sensation was 9.8 seconds. In this embodiment, when the weight ratio of WS-23 to L-menthol was 6:1, the onset speed and duration of cooling sensation reached the optimal balance point, and the overall sensory score was the highest among all embodiments, proving that (3~7):1 is a better engineering range. Example

[0037] Purpose of this implementation: This embodiment aims to verify the sensory performance when the molar ratio of total acid (benzoic acid + lactic acid) to nicotine is in the upper end of the preferred range (1.2~1.8:1), in order to determine the rationality of the excess range of this acid, and at the same time verify the performance boundary when the molar ratio of benzoic acid to lactic acid is slightly lower than 7:1.

[0038] Ingredients: By weight percentage, glycerin 44.00%, propylene glycol 40.55%, nicotine 5.00%, benzoic acid 5.30%, lactic acid 0.60%, cooling agent WS-23 3.50%, L-menthol 0.50%, ethyl maltol 0.40%, vanillin 0.15%, and the sum of the weight percentages of all components is 100%.

[0039] Implementation steps: Following the above preparation method, feed the materials in sequence, stir, heat, let stand and age for 14 hours, filter and collect the finished product.

[0040] Implementation Results: Calculations showed that in this embodiment, the molar ratio of benzoic acid to lactic acid was 6.52:1, the molar ratio of total acid to nicotine was 1.62:1, the weight ratio of WS-23 to L-menthol was 7.00:1, the weight ratio of ethyl maltol to vanillin was 2.67:1, the weight ratio of propylene glycol to glycerin was 0.922:1, and the total flavor percentage was 0.55%. Sensory Evaluation Results: The VAS score for throat irritation was 1.9, the lowest among all embodiments, indicating that when the molar ratio of total acid to nicotine was controlled at 1.62:1, the nicotine protonation was most complete, the free alkali residue was extremely low, and the throat smoothness was optimal. The cooling sensation onset time was 0.4 seconds, and the cooling sensation duration was 9.0 seconds. This embodiment verifies that even if the molar ratio of benzoic acid to lactic acid is slightly lower than 7:1, as long as the molar ratio of total acid to nicotine is maintained within the preferred range, an excellent low-irritation effect can still be achieved. Example

[0041] Purpose of implementation: This embodiment aims to verify the atomization compatibility and taste purity of the formulation when the ratio of propylene glycol to glycerol is in the preferred range (0.8~0.95:1), the ratio of ethyl maltol to vanillin is in the preferred range (2~3.5:1), and the vanillin propylene glycol acetal content is in the preferred range (0.2%~0.4%).

[0042] Ingredients: By weight percentage, glycerin 46.00%, propylene glycol 38.45%, nicotine 5.00%, benzoic acid 5.00%, lactic acid 0.50%, cooling agent WS-23 3.50%, L-menthol 0.80%, ethyl maltol 0.35%, vanillin 0.15%, vanillin propylene glycol acetal 0.25%, the sum of the weight percentages of all components is 100%.

[0043] Implementation steps: Following the above preparation method, feed the materials in sequence, stir, heat, let stand and age for 24 hours, filter and collect the finished product.

[0044] Implementation Results: Calculations showed that in this embodiment, the weight ratio of propylene glycol to glycerin was 0.836:1, the molar ratio of benzoic acid to lactic acid was 7.38:1, the molar ratio of total acid to nicotine was 1.51:1, the weight ratio of WS-23 to L-menthol was 4.375:1, the weight ratio of ethyl maltol to vanillin was 2.33:1, the vanillin propylene glycol acetal content was 0.25%, and the total flavor weight percentage was 0.75%. Sensory Evaluation Results: Throat irritation VAS score was 2.2; cooling onset time was 0.38 seconds; cooling duration was 9.3 seconds. At this ratio, the atomizing fluid viscosity is moderate, which is suitable for the oil conduction rate of mainstream ceramic core atomizers. Furthermore, the ethyl maltol and vanillin are compounded in a ratio of 2.33:1. Combined with the slow-release aroma-enhancing effect of vanillin propylene glycol acetal, the minty coolness is pure and free of impurities, and the aftertaste is clean, which verifies the synergistic compatibility of each optimal range.

[0045] Comparative Example 1 Purpose of this comparative example: This example aims to verify the sensory performance of benzoic acid as the sole salt-forming agent without the addition of lactic acid, under the premise of the same total acid to nicotine molar ratio, so as to highlight the necessity and synergistic effect of mixing lactic acid and benzoic acid in a specific molar ratio in this invention.

[0046] Ingredients: By weight percentage, glycerin 45.00%, propylene glycol 38.19%, nicotine 5.00%, benzoic acid 5.70%, cooling agent WS-23 3.50%, L-menthol 1.45%, ethyl maltol 0.70%, vanillin 0.23%, vanillin propylene glycol acetal 0.23%, with the sum of the weight percentages of all components being 100%. No lactic acid was added in this comparative example; benzoic acid was used solely as a salt-forming agent.

[0047] Implementation steps: Following the same preparation method as in Example 1, feed the materials sequentially, stir, heat, let stand and age for 18 hours, filter and collect the finished product.

[0048] Results: Calculations showed that the molar ratio of benzoic acid to nicotine in this comparative example was 1.51:1, and the molar ratio of total acid to nicotine was also 1.51:1, consistent with the total acid / nicotine molar ratio in Example 1. The weight ratio of WS-23 to L-menthol was 2.41:1, the same as in Example 1. Sensory evaluation results: The VAS score for throat irritation was 4.3 points, significantly higher than the 2.1 points in Example 1; the onset time of the cooling sensation was 0.5 seconds, and the duration of the cooling sensation was 9.0 seconds, with no significant difference in cooling sensation indicators compared to Example 1.

[0049] Comparative Conclusion: Under the premise of the same total acid to nicotine molar ratio, the VAS score for throat irritation of the single benzoic acid system (4.3 points) was significantly higher than that of the mixed acid system of benzoic acid and lactic acid (Example 1, 2.1 points), with a reduction of up to 51.2%. This indicates that lactic acid is not a simple replacement or conventional addition of benzoic acid; rather, the two produce a synergistic protonation effect within a specific molar ratio range, which can more fully neutralize free nicotine and significantly reduce irritation. This effect is something that those skilled in the art could not have predicted based solely on the existing technology of salt formation of single benzoic acid, strongly confirming the core technical significance of the specific ratio of benzoic acid and lactic acid as a mixed salt-forming agent in this invention.

[0050] Summary of the implementation effects of each embodiment: All five embodiments described above achieved a rapid onset (0.35-0.5 seconds) and a sustained (8.2-9.8 seconds) cooling sensation while maintaining low throat irritation (VAS score 1.9-2.3). Among them, Embodiment 3 showed the best overall performance (VAS 2.0, onset 0.35 seconds, duration 9.8 seconds) when the weight ratio of WS-23 to L-menthol was 6:1; Embodiment 4 showed the lowest irritation (VAS 1.9) when the molar ratio of total acid to nicotine was 1.62:1. These embodiments collectively demonstrate that when the molar ratio of benzoic acid to lactic acid is controlled at 7-12:1, the molar ratio of total acid to nicotine at 1.2-1.8:1, and the weight ratio of WS-23 to L-menthol at 2-9:1 (preferably 3-7:1), the formulation of this invention can stably achieve both low irritation and a stepped cooling sensation. Comparative Example 1 further confirms that the addition of lactic acid is not optional, but a key technical means to achieve a low-irritation effect in synergy with benzoic acid.

[0051] Compared with Examples 1-5 and Comparative Example 1, Examples 1-5 of this invention all use glycerin and propylene glycol as a composite solvent, nicotine as the active ingredient, a mixture of benzoic acid and lactic acid as a salting agent, and are compounded with the cooling agent WS-23 and L-menthol, while adding different flavor combinations. In each example, the molar ratio of benzoic acid to lactic acid is controlled at around 7.38:1 (except for Example 4, which is 6.52:1, still close to the lower limit of the range of 7~12:1), the molar ratio of total acid (the sum of benzoic acid and lactic acid) to nicotine is maintained between 1.51:1 and 1.62:1, the weight ratio of WS-23 to L-menthol is in the range of 2.41:1 to 8.75:1, and the weight ratio of ethyl maltol to vanillin is between 2.00:1 and 3.04:1. In sensory evaluation, the VAS scores for throat irritation in the five examples ranged from 1.9 to 2.3, all significantly lower than the industry-acceptable threshold (above 4.0). Example 4, with a total acid to nicotine molar ratio of 1.62:1, achieved the lowest irritation (1.9 points), demonstrating that nicotine protonation was most complete within this acid excess range, resulting in extremely low free alkali residue. The cooling onset time for all examples was within 0.35 to 0.5 seconds, reflecting the rapid cooling effect of the combination of WS-23 and L-menthol; the duration of the cooling sensation ranged from 8.2 to 9.8 seconds. Example 3 (WS-23 to L-menthol weight ratio 6:1) achieved the optimal overall cooling performance with an onset time of 0.35 seconds and a duration of 9.8 seconds, indicating that when the ratio is within the preferred range of 3 to 7:1, the instantaneous burst of cooling and the long-lasting cooling sensation achieve the best synergistic balance. Example 2 added isoamyl acetate to impart a fresh, fruity base to the mint. Example 5 adjusted the ratio of propylene glycol to glycerin to 0.836:1 and added vanillin propylene glycol acetal, verifying that the viscosity of the atomized liquid at this ratio matched the wicking rate of mainstream ceramic cores, and that the fragrance was released slowly with a pure aftertaste. Therefore, within the parameter range defined in the claims, regardless of changes in the specific fragrance or fluctuations in the cooling agent ratio, the formulation of this invention can stably achieve the technical effects of low irritation and a stepped cooling sensation, demonstrating its broad applicability and robustness.

[0052] Comparative Example 1 maintained the same total acid to nicotine molar ratio (1.51:1) and WS-23 to L-menthol weight ratio (2.41:1) as Example 1, except that the mixed acid system was replaced with benzoic acid alone, with no lactic acid added. Sensory evaluation results showed that Comparative Example 1 had a VAS score of 4.3 for throat irritation, while Example 1, at the same total acid / nicotine ratio, only scored 2.1, representing a 51.2% reduction in irritation. Although the cooling onset time and duration (0.5 seconds, 9.0 seconds) of Comparative Example 1 were not significantly different from those of Example 1 (0.4 seconds, 9.5 seconds), its significant disadvantage in reducing irritation revealed the key role of lactic acid: lactic acid is not simply a pH adjuster or a conventional excipient, but rather forms a synergistic protonation effect with benzoic acid. Through the synergistic effect of the two organic acids at the molecular level, it can more efficiently neutralize free nicotine, making the nicotine salt system more stable and mild. Even with increased dosage, benzoic acid alone cannot achieve the low-irritant effect of a mixed acid system with the same total acid content. This comparison fully demonstrates that the core technical means for achieving unexpected low-irritant effects, as specified in this invention—"benzoic acid and lactic acid mixed in a specific molar ratio (7~12:1, with excess total acid"—is something that those skilled in the art could not easily conceive of or simply replace based on the conventional approach of single-acid salt formation. In summary, all five embodiments of this invention exhibit excellent and consistent sensory performance, while the comparative scheme lacking lactic acid shows significant deterioration. This strongly confirms the integrity and non-obviousness of the technical solution of this invention, demonstrating significant inventiveness and practical value.

[0053] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

[0054] In conclusion, the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A refreshing mint-flavored e-cigarette oil formula, characterized in that, By weight percentage, it includes the following components: Glycerin 42%~48%; Nicotine content: 4.5%~5.5%; Benzoic acid 4.5%~5.5%; Lactic acid 0.4%~0.6%; Cooling agent WS-233.0%~4.0%; L-Menthol 0.3%~1.5%; Fragrance content: 0.1%~1.0%; The balance is propylene glycol; Furthermore, the molar ratio of benzoic acid to lactic acid is 7~12:1, the weight ratio of WS-23 to L-menthol is 2~9:1, and the sum of the molar amounts of benzoic acid and lactic acid is greater than the molar amount of nicotine.

2. The refreshing mint-flavored e-cigarette oil formula as described in claim 1, characterized in that, The weight ratio of propylene glycol to glycerin is 0.8 to 0.95:

1.

3. The refreshing mint-flavored e-cigarette oil formula as described in claim 1, characterized in that, The weight ratio of nicotine to benzoic acid is 1:0.95~1.

05.

4. The refreshing mint-flavored e-cigarette oil formula as described in claim 1, characterized in that, The flavoring contains ethyl maltol and vanillin, and the weight ratio of ethyl maltol to vanillin is 2~3.5:

1.

5. The refreshing mint-flavored e-cigarette oil formula as described in claim 1, characterized in that, The fragrance also contains isoamyl acetate, which accounts for 0.05% to 0.15% by weight.

6. The refreshing mint-flavored e-cigarette oil formula as described in claim 1, characterized in that, The fragrance also contains vanillin propylene glycol acetal, which is 0.2% to 0.4% by weight.

7. The refreshing mint-flavored e-cigarette oil formula as described in claim 1, characterized in that, The ratio of the sum of the molar amounts of benzoic acid and lactic acid to the molar amount of nicotine is 1.2 to 1.8:

1.

8. The refreshing mint-flavored e-cigarette oil formula as described in claim 1, characterized in that, The total weight percentage of the fragrance is 0.2% to 0.8%.

9. The refreshing mint-flavored e-cigarette oil formula as described in claim 1, characterized in that, The weight ratio of WS-23 to L-menthol is 3~7:

1.

10. The refreshing mint-flavored e-cigarette oil formulation as described in claim 1, characterized in that, The nicotine content in the formula is 48~52mg / ml.

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