Water-in-oil system pre-makeup cream and preparation method thereof

Abstract

The invention relates to the technical field of cosmetics, in particular to water-in-oil system pre-makeup cream and a preparation method thereof. The water-in-oil system pre-makeup cream comprises the following components in parts by weight: cosmetic-grade purified water; and cetyl PEG (Polyethylene Glycol) / PPG-10 / 1 polydimethylsiloxane. A polydimethylsiloxane; isononyl isononanoate; synthetic wax; microcrystalline wax; glycerol; 1, 3-propylene glycol / caprylyl glycol / ethylhexylglycerin; butanediol; sodium chloride; and a compound of polyoxyethylene (20) sorbitan monolaurate and polyoxypropylene (4) sorbitan monolaurate is prepared from the polyoxyethylene (20) sorbitan monolaurate and the polyoxypropylene (4). The water-in-oil system pre-makeup cream provided by the invention can realize 80% high water phase stable bearing, and provides sufficient moisturizing reserve for dry skin; meanwhile, in the smearing process, instant film forming and water locking can be achieved, the water retention rate is increased to 85% or above, and the problem that the water supplementing effect is attenuated is solved, so that the double effects of instant water locking and long-acting moisturizing are achieved, and the contradiction between water locking and skin feeling is eliminated.

Description

Technical Field

[0001] This application relates to the technical field of cosmetics, and more particularly to a water-in-oil makeup primer and its preparation method. Background Technology

[0002] Makeup primers are pre-treatment products used in the cosmetics industry before applying foundation. Their core function is to improve the skin's surface condition, providing a good foundation for subsequent base makeup (such as liquid foundation and cream foundation), thereby enhancing the adherence, lasting power, and smoothness of the makeup finish. As consumers' demands for more refined makeup and better skincare increase, makeup primers have become an important part of their daily makeup routine, especially for those with dry skin, where products that combine moisturizing and makeup base functions are in high demand. Currently, makeup primers are mainly divided into two categories based on their dispersion system: oil-in-water (O / W) and water-in-oil (W / O). Among them, oil-in-water products have a relatively light texture and are easy to wash off, but their water phase carrying capacity is limited; water-in-oil products, on the other hand, have a stronger water-locking ability and can form a protective film on the skin surface, which is more in line with the moisturizing needs of dry skin, and therefore have become one of the mainstream technologies for dry-skin-friendly makeup primers.

[0003] Although existing oil-in-water makeup primers outperform water-in-oil primers in terms of moisturizing performance, key technological bottlenecks still exist in practical applications to address the "long-lasting hydration and moisture retention" needs of dry skin. Specifically: (1) Low water phase capacity and insufficient moisturizing reserve: Currently, most water-in-oil makeup primers on the market have a water phase content of only 40-60% due to the sensitivity of the system's stability to the water phase ratio. An excessively high water phase ratio can easily lead to emulsion demulsification and stratification of the water-in-oil system. Therefore, the industry usually controls the water phase ratio to below 60%. This water phase ratio can only provide basic moisture to the skin and cannot meet the core need of dry skin (especially in autumn and winter, and in extremely dry environments such as air-conditioned rooms) for "high moisturizing reserve", becoming the primary factor restricting the moisturizing effect.

[0004] (2) High water evaporation rate and severely reduced moisturizing effect: Existing products require application and massage to promote absorption during use. However, during this process, a large amount of free water in the aqueous phase evaporates due to large-area contact with air and frictional heat generation. Experiments have shown that the actual water content retained by the skin is less than 30% of the initial aqueous phase content. This results in the skin quickly returning to a dry state after the "instant hydration" effect wears off, and subsequent makeup is still prone to problems such as caking, flaking, and powderiness. The moisturizing effect cannot be effectively converted into long-lasting moisturizing power.

[0005] (3) Mismatch between film-forming speed and water-locking requirements: In order to alleviate the problem of water evaporation, some products try to increase wax ingredients (such as microcrystalline wax and beeswax) to improve film-forming properties. However, traditional waxes have a slow film-forming speed, usually requiring 3-5 minutes after application to form a complete film. During the film-forming waiting process, a large amount of water is lost, making it impossible to achieve "instant water-locking". If the wax content is further increased to speed up the film-forming speed, the cream will become thick and sticky, and it will be easy to pill when applied, which will damage the smooth effect of the makeup base and fall into the dilemma of "water-locking and skin feel".

[0006] Therefore, improving the aforementioned technical bottlenecks in water-in-oil makeup primers is a core issue that the industry urgently needs to address. Summary of the Invention

[0007] This application provides a water-in-oil emulsion makeup primer and its preparation method. The water-in-oil emulsion makeup primer provided by this application can achieve a stable water phase content of 80%, providing ample moisturizing reserves for dry skin; at the same time, it can form a film and lock in water immediately during application, increasing the water retention rate to over 85%, solving the problem of diminishing moisturizing effects, thus achieving the dual effects of "immediate water locking + long-lasting moisturizing" and resolving the contradiction between "water locking and skin feel".

[0008] In the first aspect, this application provides a water-in-oil makeup primer, which adopts the following technical solution: A water-in-oil makeup base, comprising the following components in parts by weight: 75-80 parts cosmetic-grade purified water; 0.5-1 parts cetyl PEG / PPG-10 / 1 polydimethylsiloxane; 1-10 parts polydimethylsiloxane; 1-5 parts isononyl isononanoate; 1-5 parts synthetic wax; 0.5-1 parts microcrystalline wax; 1-5 parts glycerin; 1-3 parts 1,3-propanediol / caprylyl glycol / ethylhexylglycerin; 1-5 parts butylene glycol; 0.5-1 parts sodium chloride; and 0.2-0.5 parts polyoxyethylene (20) sorbitan monolaurate-polyoxypropylene (4) sorbitan monolaurate complex.

[0009] Cosmetic-grade purified water serves as the base solvent, dissolving water-soluble ingredients such as glycerin and butylene glycol, ensuring all components are evenly mixed to form a stable, creamy texture. It provides basic hydration, directly replenishing skin moisture, alleviating dryness, and preventing makeup from caking or flakeing during subsequent application. Additionally, it allows for adjustment of the product's consistency and feel; by controlling the amount of water, it balances the heaviness caused by other oils and waxes, making the primer easier to spread.

[0010] Cetyl PEG / PPG-10 / 1 polydimethylsiloxane is a nonionic siloxane emulsifier composed of cetyl groups (lipophilic end) and PEG / PPG polyethers (hydrophilic end), exhibiting both lipophilic and hydrophilic properties. It is a transparent liquid with high stability. Its core emulsifying function is to uniformly blend the oil-phase components (such as polydimethylsiloxane and isononyl isononanoate) and water-phase components (such as water and glycerin) in the formula, preventing product separation and ensuring the stability of the cream. Furthermore, it enhances skin smoothness, forming a thin silicone film on the skin surface during application, reducing friction and making the makeup primer easier to spread. It also lays a smooth foundation for subsequent foundation makeup and helps to minimize the appearance of pores.

[0011] Polydimethylsiloxane, commonly known as "silicone oil," is a commonly used silicone emollient in cosmetics. It has a lightweight texture, is odorless, and is highly safe. As a core emollient, it forms a breathable protective film on the skin's surface, reducing moisture loss and preventing direct irritation from the chemical ingredients in subsequent makeup. Furthermore, polydimethylsiloxane optimizes makeup longevity; the silicone film improves the adhesion of foundation to the skin, reducing patchiness caused by oil and sweat, and extending makeup wear time. Polydimethylsiloxane also improves product spreadability, reduces the viscosity of the product, and makes makeup primers smoother to apply without pulling or tugging at the skin.

[0012] Isonononyl isononanoate is a synthetic ester emollient produced by the esterification reaction of isononanoic acid and isononyl alcohol. It is a colorless, transparent liquid with a refreshing, easily absorbed, and non-sticky texture, and exhibits good compatibility with other ingredients. Its benefits include: replenishing skin's natural oils, providing moisture to dry skin or skin in dry environments, relieving dryness and tightness, and preventing makeup from caking; adjusting the texture of the cream, replacing traditional heavy oils (such as mineral oil), ensuring hydration while leaving a non-sticky feel after application, quickly forming a film without affecting subsequent makeup application; and enhancing the solubility of ingredients, helping to dissolve solid components in the formula (such as synthetic waxes and microcrystalline waxes), resulting in a more even and delicate texture.

[0013] Synthetic waxes are polymerized from hydrocarbons, have a moderate melting point (approximately 80°C), and form a stable solid upon cooling, with a delicate texture. They offer the following benefits: core thickening and shaping, increasing the consistency of the makeup primer from a "lotion-like" to a "cream-like" consistency, preventing the product from being too thin and prone to dripping, making it easier to apply and control the amount used; enhancing skin smoothing, forming a thin wax film on the skin's surface after application, filling in small pores and fine lines, resulting in a smoother skin feel and aiding in a "blurred" effect with subsequent foundation makeup; and improving formula stability, working synergistically with other oils and silicones to prevent the cream from melting and deforming at high temperatures, extending the product's shelf life.

[0014] Microcrystalline wax is composed of small-molecule hydrocarbons with a melting point slightly lower than synthetic waxes (approximately 60-70℃). It has a soft texture and good spreadability. It offers the following benefits: it aids in thickening and shaping; when used with synthetic waxes, it adjusts the hardness of the primer, giving it both support (preventing it from collapsing) and a soft, easy-to-apply texture; it enhances the skin's moisture retention capacity, as the wax components form a dense protective film on the skin's surface, reducing moisture evaporation and improving the primer's long-lasting moisturizing effect; and it improves the product's application feel, making the primer smoother and preventing "pilling" or a "heavy" feeling caused by an excessive proportion of synthetic waxes.

[0015] Glycerin is a classic moisturizer in cosmetics due to its strong hygroscopic properties and high safety. It offers the following benefits: actively absorbing moisture from the air or skin surface to replenish hydration and alleviate dryness, making it a core moisturizing ingredient for dry skin; improving product compatibility by promoting the blending of water and oil phases, resulting in a more even texture and reducing the risk of component separation; and enhancing makeup adherence by keeping skin hydrated, reducing gaps between makeup and skin, and preventing makeup from caking or fading.

[0016] 1,3-Propylene glycol / caprylyl glycol / ethylhexylglycerin (complex ingredient) is a three-component multifunctional ingredient. 1,3-Propylene glycol is a humectant, caprylyl glycol is a solvent and humectant, and ethylhexylglycerin is a humectant and auxiliary preservative. It offers the following benefits: Triple synergistic moisturizing: the three ingredients enhance moisturizing effects from three dimensions—"water absorption," "water retention," and "skin hydration"—providing longer-lasting hydration than a single humectant and making it suitable for dry seasons; Gentle preservative support: ethylhexylglycerin enhances the effectiveness of other preservatives (such as conventional preservatives not explicitly added in this formula), reducing the need for high-concentration preservatives and lowering the risk of skin irritation; Improved product stability: 1,3-Propylene glycol and caprylyl glycol enhance the formula's antifreeze and heat resistance, preventing the product from freezing at low temperatures and deteriorating at high temperatures.

[0017] Butylene glycol is a cosmetic-grade small-molecule polyol, a colorless and transparent liquid with moderate hygroscopicity. It combines moisturizing and solvent functions and has low skin irritation. Its benefits include: supplementing the moisturizing layer; when combined with glycerin and complex moisturizers, it forms a "small molecule + large molecule" moisturizing system, providing both rapid hydration and long-lasting moisture retention, preventing rapid dryness after a brief period of hydration; acting as a solvent carrier, it helps dissolve water-soluble active ingredients in the formula (such as plant extracts that may be added later), while promoting the penetration and absorption of other ingredients on the skin surface, enhancing their efficacy; reducing product stickiness, it replaces some of the glycerin, ensuring moisturizing power while reducing the "sticky" feeling that glycerin may cause, making the makeup primer feel more refreshing.

[0018] Sodium chloride, a high-purity version of table salt, is free of impurities, appears as a white powder, and is easily soluble in water. It offers the following benefits: It regulates the viscosity of the aqueous phase by altering its osmotic pressure, increasing the consistency of the aqueous components and helping to improve the overall stability of the makeup primer, preventing separation of the oil and water phases; it optimizes emulsification by working synergistically with emulsifiers (cetyl PEG / PPG-10 / 1 polydimethylsiloxane) to enhance emulsification capabilities, resulting in a finer, more uniform texture and reducing a grainy feel; and it controls product costs by acting as a low-cost stabilizer, replacing some expensive thickeners without affecting efficacy or skin feel, thus reducing the overall cost of the formula.

[0019] This application utilizes synthetic wax and high-viscosity silicone oil. When these two components melt at high temperatures to form an oil-wax mixture, it forms a transparent, closed-film layer when applied to the skin, preventing the moisture in the internal phase from evaporating rapidly due to contact with the external environment. Experiments have shown that mixing a linear synthetic wax with a melting point of 85℃ and polydimethylsiloxane in a 5:15 ratio, and melting it at 90℃ to form an oil-wax mixture, creates a transparent, closed-film layer. Adding 100% isomerized microcrystalline wax improves the hardness of the cream, making it easier to apply. Adding isononyl isononanoate improves the compatibility of the high-viscosity polydimethylsiloxane within the system. Adding 70-80% aqueous phase, with the aid of an emulsifier, creates a water-in-oil cream. Because the external phase is an oil-wax mixture that forms a transparent, closed-film layer when applied to the skin, the water in the internal phase is completely covered by the film, preventing evaporation due to contact with the external environment. This significantly improves the moisturizing effect on the skin.

[0020] The polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate complex is composed of "high EO (polyoxyethylene) chain" and "low PO (polyoxypropylene) chain": the high EO chain (20 units) has strong hydrophilicity and can penetrate into the interior of 80% high aqueous phase, forming hydrogen bonds with water molecules, avoiding the aggregation and precipitation of aqueous phase due to "insufficient hydrophilicity"; the low PO chain (4 units) provides moderate lipophilicity and can be tightly combined with the existing oil phase (polydimethylsiloxane, isononyl isononanoate) to build a "water-oil transition bridge" and solve the core pain point of "excessive oil-water interfacial tension and easy demulsification" in high aqueous phase water-in-oil system. It can work synergistically with the main emulsifier to assist cetyl PEG / PPG-10 / 1 polydimethylsiloxane in forming a "dual emulsification system"—the main emulsifier is responsible for building the high aqueous phase dispersion framework, and the compound fills the interfacial gaps, so that the 80% high aqueous phase can be stored at -15℃ for 30 days without water separation, improving the stability by 30% compared with the basic formula; at the same time, it can also optimize the skin feel: compared with a single emulsifier, the EO / PO chain ratio of the compound can reduce the "heaviness" of the oil phase, reduce the frictional resistance when applying the cream by 25%, and avoid the "sticky and difficult to spread" problem that is common in high aqueous phase creams.

[0021] The water-in-oil system makeup primer provided in this application can achieve a stable carrying capacity of 80% high aqueous phase, providing ample moisturizing reserves for dry skin; at the same time, it can form a film and lock in water immediately during the application process, increasing the water retention rate to over 85%, solving the problem of diminishing moisturizing effects, thus achieving the dual effects of "immediate water locking + long-lasting moisturizing" and resolving the contradiction between "water locking and skin feel".

[0022] Optionally, the polyoxyethylene (20) sorbitan monolaurate-polyoxypropylene (4) sorbitan monolaurate compound is 0.3-0.4 parts by weight.

[0023] In one specific embodiment, the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate compound is 0.2 parts, 0.3 parts, 0.35 parts, 0.4 parts, and 0.5 parts by weight.

[0024] In some specific embodiments, the weight parts of the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate compound are 0.2-0.3 parts, 0.2-0.35 parts, 0.2-0.4 parts, 0.3-0.35 parts, 0.3-0.4 parts, 0.4-0.5 parts, 0.35-0.4 parts, 0.35-0.5 parts, and 0.4-0.5 parts.

[0025] The amount of the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate compound is 0.2-0.5 parts. This compound is an "auxiliary emulsifier", and its core function is to enhance the high aqueous phase dispersion ability of the main emulsifier (cetyl PEG / PPG-10 / 1 polydimethylsiloxane, 0.5-1 parts). When the amount is less than 0.2 parts, the auxiliary stabilizing effect is insufficient and cannot solve the problem of water separation at -15℃; when it is more than 0.5 parts, the excessive hydrophilicity will break the balance of the oil-in-water system and may cause the cream to separate. In addition, its EO chain (hydrophilic) has a high proportion, and excessive amount will easily increase the stickiness of the cream. 0.2-0.5 parts can balance "strengthening stability" and "maintaining smooth skin feel" and there is no sticky residue when applying.

[0026] Optionally, the water-in-oil makeup base further includes polyethylene glycol-6000 distearate, wherein the polyethylene glycol-6000 distearate is present in an amount of 0.3-0.6 parts by weight.

[0027] Optionally, the polyethylene glycol-6000 distearate is present in 0.4-0.5 parts by weight.

[0028] In one specific embodiment, the polyethylene glycol-6000 distearate is present in parts by weight of 0.3 parts, 0.4 parts, 0.45 parts, 0.5 parts, and 0.6 parts.

[0029] In some specific embodiments, the polyethylene glycol-6000 distearate is present in parts by weight of 0.3-0.4 parts, 0.3-0.45 parts, 0.3-0.5 parts, 0.4-0.45 parts, 0.4-0.5 parts, 0.4-0.6 parts, 0.45-0.5 parts, 0.45-0.6 parts, or 0.5-0.6 parts.

[0030] Polyethylene glycol-6000 distearate has a melting point of 55-60℃, between that of synthetic waxes (80℃) and microcrystalline waxes (60-70℃). When applied, it softens before synthetic waxes and hardens after microcrystalline waxes, forming a "transitional intermediate film" on the skin surface. This accelerates the spreading speed of wax components, reducing the overall film-forming time from 10-15 seconds to 7-9 seconds, thus preventing the evaporation of high-aqueous phase moisture earlier. Furthermore, PEG-6000 distearate contains two stearic acid lipophilic ends and a polyethylene glycol hydrophilic chain, giving it emulsifying capabilities. This helps the main emulsifier encapsulate tiny droplets of the aqueous phase, reducing the "droplet aggregation" phenomenon at 45℃ and improving high-temperature storage stability by 40%. Furthermore, its polyethylene glycol hydrophilic chain can form a "weak interaction" with polydimethylsiloxane in the oil phase, reducing the surface tension of the oil phase and making the oil phase more evenly coated with the water phase. Compared with simply increasing the wax content, this component can improve the film-forming speed without significantly increasing the hardness of the cream, and the skin feels "smooth and non-tight" after application.

[0031] Polyethylene glycol-6000 distearate has both "film-forming aid" and "mild emulsifier" functions, and needs to be used in conjunction with existing waxes (1-10 parts synthetic wax + 0.5-1 part microcrystalline wax). When the dosage is less than 0.3 parts, it cannot accelerate film formation (film formation time is still >10 seconds); when it is more than 0.6 parts, its high melting point (55-60℃) will significantly increase the hardness of the paste, easily causing a "grainy" or "skin-pulling" feeling during application. Furthermore, as an oil-phase auxiliary ingredient, excessive amounts of polyethylene glycol-6000 distearate will disrupt the ratio balance of the oil phase (1-10 parts polydimethylsiloxane + 1-10 parts isononyl isononanoate), potentially leading to an oil phase floating layer during storage at 45℃. 0.3-0.6 parts ensure the stability of the water-in-oil system.

[0032] Optionally, the water-in-oil makeup base also includes a trehalose-mannitol complex, wherein the trehalose-mannitol complex is present in an amount of 0.5-1 parts by weight.

[0033] Optionally, the trehalose-mannitol compound is present in an amount of 0.6-0.9 parts by weight.

[0034] In one specific embodiment, the trehalose-mannitol compound is present in the following weight proportions: 0.5 parts, 0.6 parts, 0.75 parts, 0.9 parts, and 1 part.

[0035] In some specific embodiments, the trehalose-mannitol compound is present in the following weight proportions: 0.5-0.6 parts, 0.5-0.75 parts, 0.5-0.9 parts, 0.6-0.75 parts, 0.6-0.9 parts, 0.6-1 parts, 0.75-0.9 parts, 0.75-1 parts, and 0.9-1 parts.

[0036] In the trehalose-mannitol complex, trehalose molecules can form a "hydration shell" with water molecules, converting free water in the high-aqueous phase into "bound water"—bound water evaporates at only 1 / 10 the rate of free water, significantly reducing moisture loss during application. Simultaneously, this hydration structure forms a "slow-release layer" on the skin surface, slowly releasing moisture and extending the immediate hydration from 1 hour to over 2 hours. The hydroxyl groups (-OH) of mannitol can bind to keratin in the stratum corneum, forming a "moisturizing film" that prevents the reverse evaporation of water that has already penetrated to the surface. Its small molecular size allows it to work synergistically with glycerin and butylene glycol to penetrate deeply, forming a "multi-layered moisturizing network" in the superficial layers of the skin, increasing the moisture retention rate from 85% to over 90% after 8 hours.

[0037] Furthermore, in the trehalose-mannitol compound, both trehalose and mannitol are "small molecule moisturizers," whose core function is to prolong the moisturizing effect of the high aqueous phase. When the dosage is higher than 1.0 part, although the moisturizing power is enhanced, the excessively high concentration of polyols may cause a "mild stinging sensation" in some sensitive skin (polyol penetration irritation), and may also increase the hygroscopicity of the cream, causing it to easily absorb moisture and soften after opening.

[0038] Secondly, this application provides a method for preparing a water-in-oil makeup primer, using the following technical solution: A method for preparing a water-in-oil makeup base, the method specifically including the following steps: (1) Mix the synthetic wax, cetyl PEG / PPG-10 / 1 polydimethylsiloxane, polydimethylsiloxane, isononyl isononate, and microcrystalline wax and heat to 90°C until completely dissolved. Then add the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate compound and stir for 5-8 minutes until homogeneous. This is called system one. (2) Mix cosmetic grade purified water, butylene glycol, glycerin, 1,3-propanediol / octyl glycol / ethylhexylglycerin and sodium chloride and heat to 80°C until dissolved, and record as system two; (3) Add the system two prepared in step (2) to the system one prepared in step (1) to obtain the oil-in-water system makeup cream.

[0039] Optionally, the water-in-oil makeup base further includes polyethylene glycol-6000 distearate, wherein the polyethylene glycol-6000 distearate is 0.3-0.6 parts by weight; the polyethylene glycol-6000 distearate is added along with the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate complex in the step of preparing system one.

[0040] Optionally, the water-in-oil makeup base further includes a trehalose-mannitol complex, wherein the trehalose-mannitol complex is present in an amount of 0.5-1 parts by weight; the trehalose-mannitol complex is added during the preparation of the second system.

[0041] In summary, this application includes at least one of the following beneficial technical effects: The water-in-oil system makeup primer provided in this application can achieve a stable carrying capacity of 80% high aqueous phase, providing ample moisturizing reserves for dry skin; at the same time, it can form a film and lock in water immediately during the application process, increasing the water retention rate to over 85%, solving the problem of diminishing moisturizing effects, thus achieving the dual effects of "immediate water locking + long-lasting moisturizing" and resolving the contradiction between "water locking and skin feel".

[0042] Furthermore, this application achieves the core effects of "enhanced high water phase carrying capacity, instant water locking, and high moisture retention" by adding polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate complex, polyethylene glycol-6000 distearate, and trehalose-mannitol complex to the water-in-oil system makeup primer. Detailed Implementation

[0043] Before describing the embodiments of this application in detail, it should be understood that the terminology used herein is for the purpose of describing a particular embodiment only. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the term pertains.

[0044] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0045] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0046] In this application, the terms "comprising" or "including" are open-ended expressions, meaning they include the content specified in this application but do not exclude other aspects.

[0047] This application provides a water-in-oil makeup base.

[0048] This water-in-oil makeup base comprises the following components by weight: 75-80 parts cosmetic-grade purified water; 0.5-1 part cetyl PEG / PPG-10 / 1 polydimethylsiloxane; 1-10 parts polydimethylsiloxane; 1-5 parts isononyl isononanoate; 1-5 parts synthetic wax; 0.5-1 part microcrystalline wax; 1-5 parts glycerin; 1-3 parts 1,3-propanediol / caprylyl glycol / ethylhexylglycerin; 1-5 parts butylene glycol; 0.5-1 part sodium chloride; and 0.2-0.5 parts polyoxyethylene (20) sorbitan monolaurate-polyoxypropylene (4) sorbitan monolaurate complex.

[0049] Furthermore, the water-in-oil makeup primer also includes polyethylene glycol-6000 distearate, wherein the polyethylene glycol-6000 distearate is present in an amount of 0.3-0.6 parts by weight.

[0050] Furthermore, the water-in-oil makeup base also includes a trehalose-mannitol complex, wherein the trehalose-mannitol complex is present in an amount of 0.5-1 parts by weight.

[0051] This application provides a method for preparing the above-mentioned water-in-oil system makeup primer, specifically including the following steps: (1) Mix the synthetic wax, cetyl PEG / PPG-10 / 1 polydimethylsiloxane, polydimethylsiloxane, isononyl isononate, and microcrystalline wax and heat to 90°C until completely dissolved. Then add the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate compound and stir for 5-8 minutes until homogeneous. This is called system one. (2) Mix cosmetic grade purified water, butylene glycol, glycerin, 1,3-propanediol / octyl glycol / ethylhexylglycerin and sodium chloride and heat to 80°C until dissolved, and record as system two; (3) Add the system two prepared in step (2) to the system one prepared in step (1) to obtain the water-in-oil system makeup cream. (4) Pour the prepared water-in-oil makeup base into the mold and let it cool and solidify.

[0052] Furthermore, the water-in-oil makeup base also includes polyethylene glycol-6000 distearate, which is added along with the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate complex in the step of preparing system one.

[0053] Furthermore, the water-in-oil makeup base also includes a trehalose-mannitol complex, which is added during the preparation of System Two.

[0054] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0055] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0056] In the following examples, cosmetic-grade purified water was purchased from Shanghai Kofeng Biotechnology Co., Ltd.; cetyl PEG / PPG-10 / 1 polydimethylsiloxane was purchased from Evonik Operations GmbH (ABIL EM 90); polydimethylsiloxane was purchased from Wacker Chemie (China) Co., Ltd. (BELSIL® DM 1000); isononyl isononanoate was purchased from BASF (China) Co., Ltd. (Cetiol ININ Deo); synthetic wax was purchased from Shanghai Rongzhi Materials Technology Co., Ltd. (PrecisionMelt M80); microcrystalline wax was purchased from Shanghai Rongzhi Materials Technology Co., Ltd. (SW9010); glycerin was purchased from Tyco Brown Chemical (Zhangjiagang) Co., Ltd. (Pomegranate G995U Glycerin USP 99.5%); 1,3-propanediol / octyl glycol / ethylhexylglycerin was purchased from AMT BIOTECH LTD. (UltraCare) PEC; butanediol was purchased from DAICELCORPORATION (brand name: 1,3-Butylene Glycol); sodium chloride was purchased from Yonghua Chemical Co., Ltd.

[0057] The polyoxyethylene (20) sorbitan monolaurate-polyoxypropylene (4) sorbitan monolaurate blend was prepared by mixing polyoxyethylene (20) sorbitan monolaurate and polyoxypropylene (4) sorbitan monolaurate in a 1:1 weight ratio. Polyoxyethylene (20) sorbitan monolaurate was purchased from Fujifilm and Guangchunyao (Shanghai) Chemical Co., Ltd., and polyoxypropylene (4) sorbitan monolaurate was purchased from Sigma-Aldrich.

[0058] Polyethylene glycol-6000 distearate was purchased from Nantong Chenrun Chemical Co., Ltd., and its model is thickener 638, also known as PEG6000DS. This product is non-ionic, with an HLB value of 18.4±1.

[0059] The trehalose-mannitol compound is a blend of trehalose and mannitol in a 1:1 weight ratio. The trehalose was purchased from Aivito (Shanghai) Pharmaceutical Technology Co., Ltd., model number Hipo-M; the mannitol was purchased from Hunan Jushuo Biotechnology Co., Ltd., with a purity of 99%.

[0060] The present application will be further described in detail below with reference to the embodiments and test results.

[0061] Example 1

[0062] This embodiment provides a water-in-oil makeup primer.

[0063] The preparation method of the above-mentioned water-in-oil makeup primer specifically includes the following steps: (1) Mix the synthetic wax, cetyl PEG / PPG-10 / 1 polydimethylsiloxane, polydimethylsiloxane, isononyl isononate, and microcrystalline wax and heat to 90°C until completely dissolved. Then add the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate compound and stir for 5-8 minutes until homogeneous. This is called system one. (2) Mix cosmetic grade purified water, butylene glycol, glycerin, 1,3-propanediol / octyl glycol / ethylhexylglycerin and sodium chloride and heat to 80°C until dissolved, and record as system two; (3) Add the system two prepared in step (2) to the system one prepared in step (1) to obtain the oil-in-water system makeup cream.

[0064] (4) Pour the prepared water-in-oil makeup base into the mold and let it cool and solidify.

[0065] Table 1. Some components and proportions of the water-in-oil makeup primer in Example 1 (Part 1)

[0066] Table 2. Some components and proportions of the water-in-oil makeup primers in each example and comparative example (II)

[0067] Examples 2-5 This embodiment provides a water-in-oil makeup base. The difference between the above embodiment and Embodiment 1 is that the amount of the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate complex added is shown in Table 2. The remaining operating steps are consistent with Embodiment 1.

[0068] Example 6

[0069] This embodiment provides a water-in-oil makeup base. The difference between this embodiment and Embodiment 3 is that, based on Embodiment 3, polyethylene glycol-6000 distearate is added. The specific amount added is shown in Table 2, specifically added during the preparation of System 1 along with the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate complex. All other operating steps remain consistent with Embodiment 3.

[0070] Examples 7-10 This embodiment provides a water-in-oil makeup primer. The difference between this embodiment and Embodiment 6 lies in the amount of polyethylene glycol-6000 distearate added, as shown in Table 2. All other operating steps remain the same as in Embodiment 6.

[0071] Example 11

[0072] This embodiment provides a water-in-oil makeup primer. The difference between this embodiment and Embodiment 8 is that, based on Embodiment 8, a trehalose-mannitol complex is added. The specific amount added is shown in Table 2, specifically, the trehalose-mannitol complex is added during the preparation of System Two. All other operational steps remain consistent with Embodiment 8.

[0073] Examples 12-15 This embodiment provides a water-in-oil makeup primer. The difference between this embodiment and Embodiment 11 is the amount of trehalose-mannitol complex added, as shown in Table 2. All other operating steps are consistent with Embodiment 11.

[0074] Comparative Example 1 This comparative example provides a makeup primer. The difference between the above comparative example and Example 3 is that the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate complex was not added. All other operating steps are consistent with Example 3.

[0075] Performance testing The makeup primers provided in the above embodiments and comparative examples were tested as follows.

[0076] (a) Heat resistance test at 50℃ The testing method is as follows: Take appropriate amounts of the makeup primer samples prepared in Comparative Example 1, Example 3, Example 8, and Example 13, and place them into sealed containers, ensuring that the containers have sufficient space to prevent the primer from expanding and overflowing due to heat. Place the containers containing the samples in a high-temperature test chamber at 50°C for 24 hours.

[0077] After the specified time has elapsed, remove the sample and place it at room temperature (around 25°C) until it returns to room temperature (around 25°C, recovery time 1-2 hours, 2 hours for this test). Then observe whether there are any changes in the appearance, texture, color, or odor of the sample. Record whether the cream exhibits stratification (e.g., separation of oil and water phases), thinning (significantly increased fluidity), discoloration (darkening of color or appearance of abnormal color), or odor change (development of an off-odor), etc., to determine the heat resistance of the makeup primer.

[0078] The test results are shown in Table 3.

[0079] Table 3 Results of heat resistance test

[0080] As shown in Table 3, the makeup primers prepared in the above embodiments of this application all exhibit better heat resistance stability compared to the makeup primer in Comparative Example 1. In particular, the solutions in Examples 8 and 13 showed virtually no layering and no other abnormal phenomena. Therefore, it can be inferred that the makeup primers provided in this application all possess good heat resistance stability.

[0081] (II) -18℃ Cold Resistance Test The detection method is as follows: Take appropriate amounts of the makeup primer samples prepared in Comparative Example 1, Example 3, Example 8, and Example 13, and place them into sealed containers, ensuring that the containers have sufficient space to accurately observe their changes in properties. Place the containers containing the samples in a freezer at -18°C for 24 hours.

[0082] After the specified time has elapsed, the sample is removed and placed at room temperature (around 25°C) until it returns to room temperature (around 25°C, recovery time 2-3 hours, 3 hours for this test). The physical properties of the makeup primer at low temperature and after returning to room temperature are observed and recorded, including whether the texture hardens or clumps, whether the color changes, whether the odor is abnormal, whether layering occurs, and whether the makeup removal ability is weakened during use. This is to determine the cold resistance of the makeup primer.

[0083] The test results are shown in Table 4.

[0084] Table 4 Results of cold resistance test

[0085] As shown in Table 4, the makeup primers prepared in the above embodiments of this application all exhibit better cold resistance compared to the makeup primer in Comparative Example 1. In particular, the solutions in Examples 8 and 13 showed virtually no layering and no other abnormal phenomena. Therefore, it can be inferred that the makeup primers provided in this application all possess good cold resistance.

[0086] (III) Cold (-18°C) and hot (50°C) cycle test The testing method is as follows: Take appropriate amounts of the makeup primer samples prepared in Comparative Example 1, Example 3, Example 8, and Example 13, and place them into sealed containers, ensuring that the containers have sufficient space. Place the containers containing the samples into a constant temperature test chamber, set the cycle period (-18℃ to 50℃), each cycle is 24h, including 12h at -18℃ and 12h at 50℃, and perform 7 cycles of cyclic testing.

[0087] After each cycle and at the end of the entire test, observe the changes in appearance, texture, color, and odor of the makeup primer, and record whether phenomena such as layering, thinning, hardening, clumping, discoloration, or odor change occur. Analyze the development trend of these changes with the increase of the number of cycles to evaluate the stability of the makeup primer under hot and cold cycling conditions.

[0088] The test results are shown in Table 5.

[0089] Table 5 Results of thermal cycling tests

[0090] As shown in Table 5, the makeup primers prepared in the above embodiments of this application exhibit better stability under thermal cycling test conditions than the makeup primer in Comparative Example 1. In particular, the solutions in Examples 8 and 13 showed virtually no stratification and no other abnormal phenomena. Therefore, it can be inferred that the makeup primers provided in this application possess good stability under thermal cycling test conditions.

[0091] (iv) Microbial testing The makeup primer samples prepared in Comparative Example 1, Example 3, Example 8 and Example 13 were tested in accordance with the "Cosmetic Hygiene Standard".

[0092] According to the 2015 edition of the "Cosmetic Safety Technical Specifications", the total bacterial count in non-eye and non-lip cosmetics shall not exceed 1000 CFU / g, the total number of molds and yeasts shall not exceed 100 CFU / g, and fecal coliforms, Staphylococcus aureus, and Pseudomonas aeruginosa shall not be detected; the total bacterial count in eye and non-lip cosmetics shall not exceed 500 CFU / g, the total number of molds and yeasts shall not exceed 100 CFU / g, and fecal coliforms, Staphylococcus aureus, and Pseudomonas aeruginosa shall not be detected.

[0093] The test results show that the makeup primers prepared in the above embodiments and comparative examples all meet the relevant requirements.

[0094] (v) Efficacy testing The following efficacy tests were performed on the makeup primers prepared in the embodiments and comparative examples of this application, respectively.

[0095] (1) High water phase stability bearing capacity test The testing method is as follows: Accurately weigh 50g of the makeup primer sample, place it in a centrifuge tube, and centrifuge at 3000r / min for 30min.

[0096] After centrifugation, observe the state of the makeup primer in the centrifuge tube, and calculate the proportion of the aqueous phase in the entire makeup primer system by measuring the volume of the lower aqueous phase in the centrifuge tube.

[0097] Meanwhile, the dispersion of aqueous droplets in the oil phase is observed using a microscope to determine the stability of the aqueous phase. If the droplets are uniformly dispersed and there is no obvious aggregation or sedimentation, it indicates that the aqueous phase has good stability.

[0098] To ensure the accuracy of the test, the makeup primer samples for each method were tested three times, and the average value was taken as the final result.

[0099] The test results are shown in Table 6.

[0100] (2) Moisture retention rate detection The testing method is as follows: 160 participants (aged 25-35, dry / combination dry skin) were selected and divided into 16 groups (using the makeup primers from Examples 1-15 and Comparative Example 1, respectively), with 10 participants in each group; the testing environment was a constant temperature of 25℃ and a constant humidity of 50% (simulating a normal indoor environment); before the test, volunteers cleansed their faces and sat quietly for 30 minutes in an environment with a temperature of (25±2)℃ and a relative humidity of (50±5)% to stabilize their skin condition. The initial skin moisture content of the same area (cheek) on the volunteers' face was measured using a skin moisture meter (Corneometer CM 825) and recorded as M1.

[0101] During the test, the makeup primer was evenly applied to the corresponding areas of the volunteers' faces, with a consistent application amount (0.5 g / cm²). After application, the volunteers remained seated in the same environment for 2 hours. After 2 hours, the skin moisture content of the areas where the makeup primer was applied was measured again using a skin moisture meter and recorded as M2.

[0102] The moisture retention rate of the makeup primer can be calculated using the formula: Moisture retention rate = (M2 ÷ M1) × 100%.

[0103] The test results are shown in Table 6.

[0104] (3) Water retention time test The testing method is as follows: 160 people (aged 25-35, dry / combination dry skin) were selected and divided into 16 groups (using the makeup primers of Examples 1-15 and Comparative Example 1 respectively), with 10 people in each group; the test environment was a constant temperature of 25℃ and a constant humidity of 50% (simulating the daily indoor environment); before the test, the initial skin moisture content of the same area (cheek) of the volunteers' face was measured using a skin moisture meter and recorded as N1.

[0105] During the test, the makeup primer was evenly applied to the corresponding areas of the volunteers' faces, with a consistent application amount (0.4 g / cm²). Starting from the moment of application, the skin moisture content of each area was measured every hour using a skin moisture meter and recorded as N2, N3, etc., until the skin moisture content dropped to 70% of its initial value (i.e., Nx = 0.7N1). The time at this point was recorded as Tx, which represents the primer's water-locking time.

[0106] The test results are shown in Table 6.

[0107] (4) Film formation time detection The detection method is as follows: detection is carried out by visual observation combined with image analysis software (ImageJ).

[0108] Apply the makeup primer evenly to a glass slide, ensuring a uniform thickness (e.g., 0.1 mm). Place the slides with the primer applied in an environment with a temperature of 25°C and a relative humidity of 50%. Immediately after application, photograph the slides using a digital camera to record the initial state. Then, photograph the slides every 10 seconds until the primer forms a continuous and complete film on the slide surface. Visually inspect the photographs to determine if the primer has formed a film. Simultaneously, use image analysis software to process the photographs and analyze the coverage area and film uniformity of the primer on the slides. A film formation standard is defined as primer coverage exceeding 90% and good film uniformity; the time required to achieve this standard is recorded as the film formation time.

[0109] For each scheme, conduct multiple experiments (10 times) and take the average value as the final result.

[0110] The test results are shown in Table 6.

[0111] Table 6 Efficacy Testing

[0112] As shown in Table 6, compared with the makeup primer of Comparative Example 1, the scheme of adding only polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate compound in this application can effectively increase the proportion of aqueous phase to more than 70%, the water retention rate to more than 75%, the water-locking time to 4.75h, the film-forming time to less than 11s, and the stability is also greatly improved.

[0113] Meanwhile, the scheme of adding polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate compound and polyethylene glycol-6000 distearate can further increase the proportion of aqueous phase to more than 78%, the water retention rate to more than 82%, the water-locking time to 6h, the film-forming time to less than 9s, and at the same time have good stability.

[0114] Furthermore, the present application simultaneously adds a polyoxyethylene (20) sorbitan monolaurate-polyoxypropylene (4) sorbitan monolaurate complex, polyethylene glycol-6000 distearate, and trehalose-mannitol complex, which can further increase the aqueous phase content to over 83.5%, the water retention rate to over 89%, the water-locking time to 8 hours, and the film-forming time to less than 6 seconds, while also exhibiting optimal stability.

[0115] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A water-in-oil makeup primer, characterized in that, The water-in-oil makeup base comprises the following components in parts by weight: 75-80 parts cosmetic-grade purified water; 0.5-1 parts cetyl PEG / PPG-10 / 1 polydimethylsiloxane; 1-10 parts polydimethylsiloxane; 1-5 parts isononyl isononanoate; 1-5 parts synthetic wax; 0.5-1 parts microcrystalline wax; 1-5 parts glycerin; 1-3 parts 1,3-propanediol / caprylyl glycol / ethylhexylglycerin; 1-5 parts butylene glycol; 0.5-1 parts sodium chloride; and 0.2-0.5 parts polyoxyethylene (20) sorbitan monolaurate-polyoxypropylene (4) sorbitan monolaurate complex.

2. The water-in-oil makeup primer according to claim 1, characterized in that, The weight parts of the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate compound are 0.3-0.4 parts.

3. The water-in-oil makeup primer according to claim 1, characterized in that, The water-in-oil makeup base also includes polyethylene glycol-6000 distearate, wherein the polyethylene glycol-6000 distearate is present in an amount of 0.3-0.6 parts by weight.

4. The water-in-oil makeup primer according to claim 3, characterized in that, The polyethylene glycol-6000 distearate is present in parts by weight of 0.4-0.

5.

5. The water-in-oil makeup primer according to claim 1, characterized in that, The oil-in-water makeup base also includes a trehalose-mannitol complex, wherein the trehalose-mannitol complex is present in an amount of 0.5-1 parts by weight.

6. The water-in-oil makeup primer according to claim 5, characterized in that, The trehalose-mannitol compound is present in an amount of 0.6-0.9 parts by weight.

7. A method for preparing a water-in-oil makeup base according to any one of claims 1-2, characterized in that, The preparation method specifically includes the following steps: (1) Mix the synthetic wax, cetyl PEG / PPG-10 / 1 polydimethylsiloxane, polydimethylsiloxane, isononyl isononate, and microcrystalline wax and heat to 90°C until completely dissolved. Then add the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate compound and stir for 5-8 minutes until homogeneous. This is called system one. (2) Mix cosmetic grade purified water, butylene glycol, glycerin, 1,3-propanediol / octyl glycol / ethylhexylglycerin and sodium chloride and heat to 80°C until dissolved, and record as system two; (3) Add the system two prepared in step (2) to the system one prepared in step (1) to obtain the oil-in-water system makeup cream.

8. The preparation method according to claim 7, characterized in that, The water-in-oil makeup base also includes polyethylene glycol-6000 distearate, which has a weight of 0.3-0.6 parts; the polyethylene glycol-6000 distearate is added along with the polyoxyethylene (20) dehydrated sorbitan monolaurate-polyoxypropylene (4) dehydrated sorbitan monolaurate complex in the step of preparing system one.

9. The preparation method according to claim 7, characterized in that, The water-in-oil makeup base also includes a trehalose-mannitol complex, which is 0.5-1 parts by weight; the trehalose-mannitol complex is added in the step of preparing the second system.

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