Sensitive skin care emulsion based on composite emulsification system and preparation method of sensitive skin care emulsion

Abstract

The invention relates to a sensitive skin care emulsion based on a composite emulsification system and a preparation method thereof. The emulsion comprises the following components in percentage by mass: 0.05-3.0% of plant-derived total glycosides, 3-20% of an oil phase, 1-7% of a composite emulsification system (comprising C8-C16 alkyl polyglucoside, phospholipid and acrylic acid / C10-C30 alkyl acrylate cross-linked copolymer), 2-20% of a polyol humectant and the balance of water, and does not contain a sulfate surfactant and a polyoxyethylene nonionic emulsifier. The preparation method comprises the following steps: pre-dissolving low-temperature glucoside, pre-neutralizing and hydrating an acrylic copolymer to form weak gel, pre-mixing a phospholipid oil phase, and performing high-shear emulsification and temperature-controlled cooling under a reduced pressure condition, so that the activity of the glucoside is uniformly and stably dispersed in a system, and the particle size D50 of emulsion droplets is 0.2-3.0 microns. The emulsion interface structure has the characteristics of a glycosyl hydrophilic environment and bionic lipid, is low in irritation and good in storage stability, and can reduce percutaneous water loss.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cosmetic formulations and the application of glycoside compounds, and in particular to a sensitive skin care emulsion based on a composite emulsifying system and a preparation method thereof. BACKGROUND

[0002] Sensitive skin is prone to experience adverse feelings such as stinging, tightness or burning when using skin care emulsions, and its tolerance is affected by factors such as skin barrier state, emulsion interface structure, surfactant type and solubility of active substances. In order to improve the use experience of sensitive skin, the existing technology often introduces plant extracts as soothing active ingredients, or uses non-ionic emulsifiers to reduce the impact of surfactants on stratum corneum lipids. In terms of plant activity, glycosides are used in some studies for soothing skin care products due to their abundant sources, but glycosides have problems such as insufficient solubility, crystallization or unstable dispersion in water, which affect the appearance and uniformity of the emulsion during use.

[0003] In terms of emulsifying system, traditional sensitive skin emulsions often use polyoxyethylene nonionic emulsifiers, fatty alcohol co-emulsifiers or a small amount of anionic surfactants to maintain system stability, but the structural characteristics of such emulsifying systems at the interface differ from the composition of the skin lipid membrane, which may cause tightness or increased barrier burden during use. In addition, high content of active substances, natural lipids, thickeners and other ingredients may interact during emulsification and cooling, which may cause oil droplet coalescence and phase separation, and may also affect the particle size and appearance consistency of the emulsion after storage. The existing emulsification process usually uses the method of directly emulsifying after heating the oil phase and the water phase to a certain temperature, which is difficult to fine control according to the solubility behavior or interface characteristics of specific active substances. During storage, some emulsions also have problems such as difficulty in removing bubbles, interface oxidation sensitivity, and unstable particle size, which affect the appearance, skin feel and stability of the product.

[0004] Based on the above situation, the existing technology still lacks a skin care emulsion formula and preparation scheme that can achieve interface stability, good skin compatibility and be suitable for sensitive skin in the presence of glycoside active substances. SUMMARY

[0005] The purpose of the present application is to overcome the above-mentioned problems existing in the prior art, and to provide a sensitive skin care emulsion based on a composite emulsifying system and a preparation method thereof, so that the glycoside active ingredients have good dispersion and stability in the system, and the emulsion has good skin compatibility and structural stability during use.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a sensitive skin care emulsion based on a composite emulsifying system, which comprises, by mass percentage: A. 0.05-3.0% glycoside soothing component, the glycoside soothing component being total glycosides from plant sources, the mass fraction of glycoside compounds in the total glycosides being 50-95%; B. 3-20% oil phase component; C. 1-7% complex emulsification system, the complex emulsification system comprising: C1. 0.3-4.0% glycoside nonionic emulsifier, being C8-C16 alkyl polyglucoside or a mixture thereof; C2. 0.1-2.0% phospholipid emulsifier; C3. 0.1-2.0% acrylic copolymer emulsifier, being a crosslinked copolymer obtained by copolymerization of acrylic acid and C10-C30 alkyl acrylate as monomers; D. 2-20% humectant, being one or more polyhydric alcohols; E. the balance being water; wherein the mass ratio of the glycoside soothing component to the complex emulsification system is 1:4-40, the mass ratio of the glycoside nonionic emulsifier to the phospholipid emulsifier is 1:0.2-2, and the skin care emulsion does not contain sulfate surfactant and polyoxyethylene nonionic emulsifier.

[0007] As a further improvement of the present application, the glycoside soothing component is a combination of total asiaticoside, total glycyrrhiza, and total sea buckthorn glycoside, wherein the total mass fraction of asiaticoside and hydroxyl asiaticoside in the total asiaticoside is 30-80%.

[0008] As a further improvement of the present application, the glycoside nonionic emulsifier is selected from decyl glucoside, decyl-octyl glucoside, coco glucoside, and a mixture thereof, and the average glycosyl substitution degree of the glycoside nonionic emulsifier is 1.1-2.5.

[0009] As a further improvement of the present application, the acrylic copolymer emulsifier forms a gel system after neutralization and hydration under the condition of 25°C and pH 5.0-6.2, and the apparent viscosity of the gel system is 1000-6000 mPa·s at a shear rate of 1 s -1 .

[0010] As a further improvement of the present application, the oil phase component comprises medium-chain triglyceride and solid lipid, the mass ratio of the medium-chain triglyceride to the solid lipid is 2-8:1, and the solid lipid is selected from one or more of shea butter, hydrogenated vegetable oil, and cetyl stearyl alcohol.

[0011] The second aspect of the present application provides a preparation method of the sensitive skin care emulsion based on the complex emulsification system as described above, comprising the following steps: (1) Glycoside pre-solution: the glycoside soothing component is added into water and humectant, stirred at 20-35℃ for 10-60min to obtain a glycoside pre-solution, wherein the mass ratio of the glycoside soothing component to the humectant is 1:3-20; (2) Acrylic acid copolymer pre-hydration: the acrylic acid copolymer emulsifier is dispersed in water, a neutralizing agent is added to adjust the pH to 5.0-6.2, and the system is statically hydrated at 20-35℃ for 60-180min to obtain a uniform acrylic acid copolymer gel; (3) Phospholipid oil phase pre-mixing: the oil phase components are mixed with the phospholipid emulsifier, and stirred at 50-75℃ until a uniform oil phase pre-mixing solution is formed; (4) Water phase pre-mixing: the glycoside pre-solution obtained in step (1), the glycoside non-ionic emulsifier, the acrylic acid copolymer gel obtained in step (2), and water are mixed, and stirred at 50-75℃ to obtain a water phase pre-mixing solution; (5) Emulsification and cooling: the oil phase pre-mixing solution obtained in step (3) is slowly added into the water phase pre-mixing solution obtained in step (4) at a shearing speed of 3000-8000r / min for 5-20min, and after emulsification, the system is kept at 65-75℃ for 3-10min, and then cooled to 25-35℃ under stirring to obtain a sensitive skin care emulsion.

[0012] As a further improvement of the present application, the mass concentration of the glycoside soothing component in the glycoside pre-solution in step (1) is 1-10wt%.

[0013] As a further improvement of the present application, the mass ratio of the acrylic acid copolymer to water in step (2) is 1:20-80, and the neutralizing agent is selected from one or more of sodium hydroxide, potassium hydroxide and ammonia.

[0014] As a further improvement of the present application, the volume median particle size D50 of the emulsion obtained after emulsification in step (5) is 0.2-3.0μm.

[0015] As a further improvement of the present application, the emulsification and cooling process in step (5) is carried out under reduced pressure, and the absolute pressure of the system is 20-80kPa.

[0016] The present application has the following beneficial effects by adopting the above technical solutions: The present application forms a stable structure with both hydrophilic and biomimetic lipid characteristics at the emulsion interface by the combination design of total glycosides, non-ionic glycoside emulsifiers, phospholipids and specific acrylic cross-linked copolymer. The total glycosides contain a high proportion of glycosidic bond structure, which is usually prone to crystallization or precipitation in the aqueous phase. The present application uses it together with C8-C16 alkyl polyglucoside in the interface layer to form a continuous sugar-based hydrophilic environment at the interface, which is conducive to reducing the aggregation of glycoside activity in the aqueous phase, while reducing the extraction of conventional alkyl emulsifiers on the sebum film and improving the tolerance of sensitive skin. The addition of phospholipids can form a biological bilayer at the interface of the oil droplet, so that the emulsion droplet has good mechanical flexibility and skin compatibility, thereby improving the extensibility and softness of the application process. The mass ratio of the above three types of ingredients is limited, which can keep the interface layer stable arrangement, avoid active crystallization, interface film rupture or oil droplet coalescence, and obtain an emulsion structure with uniform particle size and no stratification during the storage period.

[0017] The acrylic cross-linked copolymer forms a weak gel structure with moderate viscosity under the condition of pH 5.0-6.2 after sufficient neutralization and hydration, which can quickly establish a continuous phase during the emulsification process, providing necessary three-dimensional support for oil droplets, reducing shear stress at the interface, and inhibiting contact and fusion between emulsion droplets. The apparent viscosity of the gel is limited to the range of 1000-6000 mPa·s, so that the system has sufficient structure and does not produce heavy and dragging touch. The gel skeleton and glycoside emulsifier, phospholipid together constitute a composite emulsification system, which plays a role in emulsification, stabilization and visual uniformity at the interface, so that the emulsion can still obtain good stability and skin feel without introducing polyoxyethylene surfactants.

[0018] The combination of medium-chain triglycerides and solid lipids is used in the oil phase part, and the mass ratio is limited to the range of 2-8:1, so that the oil phase has both fluidity and certain solid support, which can maintain the morphological integrity of the oil droplets during the cooling process and reduce the oil phase migration phenomenon during storage. The good spreading performance of medium-chain triglycerides can offset the sticky feeling that solid lipids may bring, making the overall feeling smooth and light. The oil phase structure cooperates with the aforementioned composite emulsification system to make the emulsion have good skin feel and stability.

[0019] In the preparation process, the total glycosides are treated by low-temperature pre-solution method to dissolve in part of water and humectants in the range of 20-35℃, thereby avoiding the problems of degradation, color deepening or reduced solubility that may occur under high temperature conditions. The pre-solution is in a uniform and stable state before entering the emulsification process, which is conducive to preventing active crystallization during subsequent emulsification. The acrylic cross-linked copolymer is first neutralized and hydrated for a long time before emulsification, so that the chain segments are fully stretched to form a uniform gel, avoiding phase separation caused by instantaneous viscosity change during shearing.

[0020] In the oil phase part, the present application makes the phospholipid form a more uniform dispersion structure in the oil by premixing the phospholipid with the oil phase at 50-75°C, so that it is easier to form a complete interface film during emulsification, thereby improving the shear resistance of the emulsion droplets. After emulsification, short-term incubation at 65-75°C can further arrange and stabilize the glycoside emulsifier, total glycoside and phospholipid at the interface, thereby reducing the particle size growth and phase instability caused by interface disturbance during the cooling stage. The emulsification and cooling process is carried out in a reduced pressure environment of 20-80 kPa, which helps to reduce the amount of air entrainment and the solubility of oxygen, so that the activity of the glycoside is not easily oxidized, the volume fraction of the bubbles in the emulsion is controlled at a low level, and the overall appearance and uniformity are improved.

[0021] Through the overall setting of the above formula structure and process steps, the present application obtains a sensitive skin care emulsion with low irritation, high interface stability, long storage period and excellent skin feel. The structure of the system depends on the interaction between the total glycoside, glycoside surfactant, phospholipid and low crosslinking acrylic acid gel, and at the same time, the comprehensive effects of activity stability, skin compatibility and emulsion structure stability are obtained. DETAILED DESCRIPTION

[0022] The specific embodiments of the present application will be described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0023] Unless otherwise defined, all scientific and technical terms used in the present application have the same meanings as commonly understood by one of ordinary skill in the art to which the present application pertains.

[0024] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by one of ordinary skill in the art without creative work belong to the scope of protection of the present application.

[0025] The materials, reagents and the like used in the following examples have no special instructions and can be obtained from commercial channels.

[0026] The present application will be described in detail below with reference to specific embodiments, which are used to understand but not limit the present application.

[0027] Example 1 The specific sources of the key raw materials used in this embodiment are as follows: 1. Centella Asiatica Extract - Total Glycosides 80% produced by Xi'an Jintai Bioengineering Co., Ltd. is an extract of the above-ground part of Centella Asiatica. The nominal total glycoside content is 80wt%, mainly triterpenoid glycosides (such as asiaticoside, hydroxyasiaticoside and their related derivatives), which is a food and cosmetic grade raw material.

[0028] 2. Total glycyrrhizin: The selected product is Licorice Extract - Glycyrrhizic Acid 20% powder extract produced by Hunan Yike Biotechnology Co., Ltd. The nominal total content of glycyrrhizic acid and its glycosides is ≥20wt%. It is a cosmetic-grade plant extract and is used as a source of total glycyrrhizin. It is a food and cosmetic-grade raw material.

[0029] 3. Sea buckthorn total glycosides, selected from Sea Buckthorn Fruit Extract - Flavones 20% produced by Hunan Yike Biotechnology Co., Ltd., is a sea buckthorn fruit extract with a nominal total flavonoid / total glycoside content of approximately 20wt%. The main components include sea buckthorn flavonoid glycosides and related glycoside compounds, and it is a food and cosmetic grade raw material.

[0030] 4. Glycoside nonionic emulsifiers (C8-C16 alkyl polyglucosides), all glycoside nonionic emulsifiers are manufactured by BASF SE: Plantacare® 2000 UP (Decyl Glucoside); Plantacare® 810 UP (Caprylyl / Capryl Glucoside). The dosage of Plantacare® 2000 UP is 1.50% by weight, and the dosage of Plantacare® 810 UP is 1.00% by weight, totaling approximately 2.50% of the emulsion system's mass fraction.

[0031] 5. Phospholipid emulsifier: NIKKOL LECINOL® S-10 provided by Nikko Chemical Co., Ltd., INCI name Hydrogenated Lecithin, is hydrogenated soybean lecithin containing 25-30 wt% phosphatidylcholine (PC).

[0032] 6. The acrylic copolymer emulsifier used is Carbopol® Ultrez 20 Polymer from Lubrizol Advanced Materials, Inc., with the INCI name Acrylates / C10-30 Alkyl Acrylate Crosspolymer, which is a hydrophobically modified acrylic / C10-30 alkyl acrylate crosspolymer.

[0033] 7. Medium chain triglyceride, MCT - Caprylic / Capric Triglyceride supplied by Acme-Hardesty Company, is a triglyceride mainly composed of C8-C10 fatty acids, cosmetic grade.

[0034] The raw materials not specifically marked with manufacturer and brand in this example, such as purified water, glycerin, propylene glycol, butylene glycol, citric acid, sodium citrate, disodium ethylenediaminetetraacetate, sodium hydroxide, and shea butter, hydrogenated vegetable oil, cetyl stearyl alcohol, etc., are all conventional commercial-grade raw materials meeting the requirements of current cosmetic regulations, which can be directly obtained from multiple suppliers by those skilled in the art.

[0035] Examples 1-4 and Comparative Example 1 specifically disclose a sensitive skin care emulsion based on a composite emulsifying system, the formula (by mass percentage) is shown in Table 1 below:

[0036] This example specifically discloses a preparation method of a sensitive skin care emulsion based on a composite emulsifying system, which comprises the following steps: (1) Glycoside pre-solution, add glycerin 5.00wt%, butylene glycol 2.00wt%, pentanediol 1.00wt% into a preparation tank, add 15.00wt% of deionized water, and make the system temperature 25℃. Under the stirring speed of 350r / min, add total glucoside of comfrey, total glycoside of licorice and total glucoside of sea buckthorn in turn, continuously stir for 30min, and get a transparent slightly yellow glycoside pre-solution.

[0037] (2) Acrylic acid copolymer pre-hydration, add deionized water (about 20wt%) into another container, slowly sprinkle Carbopol® Ultrez20 (the amount is 0.90wt% of the formula mass), and stir at 300r / min for 15min to make it uniformly dispersed. After standing for 10min, add 10wt% sodium hydroxide solution dropwise, adjust the pH of the system to 5.8. Then hydrate at 25℃ for 120min, get a transparent and uniform acrylic acid copolymer gel without visible gel particles.

[0038] The apparent viscosity of the gel is measured to be 3200mPa·s at 25℃ and shear rate 1s -1 .

[0039] (3) Premixing of phospholipid oil phase, add medium-chain triglyceride 6.00 wt%, shea butter 2.00 wt%, hydrogenated vegetable oil 1.00 wt% and cetyl stearyl alcohol 1.00 wt% into an oil phase tank, heat to 65°C and stir until completely melted. Add hydrogenated lecithin, continue stirring at 65°C and 400 r / min for 20 min to obtain a uniform oil phase premix.

[0040] (4) Premixing of water phase, mix the glycoside pre-solution obtained in step (1) with the acrylic acid copolymer gel obtained in step (2), and heat to 65°C. Add Plantacare® 2000UP (1.50 wt%) and Plantacare® 810UP (1.00 wt%) under stirring at 400 r / min, and stir for 15 min. Then add EDTA-2Na (0.05 wt%) and citric acid / sodium citrate buffer (0.30 wt%), and add deionized water to the total amount of the formulation to obtain a uniform and transparent water phase premix.

[0041] (5) Emulsification and cooling, in a vacuum emulsification kettle, heat the water phase premix to 68°C, and stabilize the absolute pressure of the system at 40 kPa. Start the homogenizer, and slowly add the oil phase premix obtained in step (3) into the water phase within 8 min at a shear speed of 5000 r / min, and emulsify for 10 min. After emulsification, continue to heat at 68°C for 5 min. After the heating is completed, cool to 28°C while maintaining stirring, and maintain the vacuum condition during the cooling process to keep the pressure at 40-60 kPa, so as to reduce the dissolved air and entrained bubbles in the system.

[0042] After the cooling is completed, the pH is measured to be 5.7, and adjusted to 5.5-6.0, to obtain a milky white and uniform sensitive skin care emulsion.

[0043] The volume median particle size D50 of the obtained emulsion is 0.35 μm as measured by a laser particle size analyzer; after accelerated storage at 45°C for three months, the D50 is 0.38 μm, and no significant phase separation or oil droplet coalescence is detected.

[0044] Example 2, the preparation method of the embodiment is the same as that of Example 1 except for the following differences.

[0045] In the glycoside pre-solution stage, the temperature of the system is set to 24°C, and the stirring time is 20 min.

[0046] The acrylic acid copolymer is hydrated at 25°C for 90 min, and the apparent viscosity of the obtained gel is 2200 mPa·s.

[0047] The emulsification conditions are changed to: homogenizer speed 4000 r / min, emulsification time 8 min. After emulsification, heat at 62°C for 5 min.

[0048] The emulsification and cooling process was carried out at an absolute pressure of 50 kPa.

[0049] The obtained emulsion had a D50 of 0.50 μm, and the particle size was 0.55 μm after 3 months of acceleration at 45℃, and no obvious stratification was observed.

[0050] Example 3, the preparation method of this example was basically the same as that of Example 1, and only the following steps were adjusted.

[0051] The addition ratio of the acrylic copolymer was 1.50 wt% based on the mass of the formula, and the mass ratio of the acrylic copolymer to water was 1:30, and the neutralization pH was 5.5. The hydration was carried out at 25℃ for 180 min, and a weak gel system with an apparent viscosity of 4800 mPa·s was obtained.

[0052] The emulsification conditions were: homogenization speed 6000 r / min, emulsification time 12 min. The emulsification process was carried out at an absolute pressure of 30 kPa. During the cooling process, the stirring speed was increased to 500 r / min to prevent local crystallization of the oil phase.

[0053] The obtained emulsion had a cream-like texture, and the D50 was 0.45 μm; the particle size was 0.50 μm after 3 months of acceleration at 45℃, and the appearance was stable without crystallization.

[0054] Example 4, the preparation method of this example was the same as that of Example 1, and only the homogenization conditions of the emulsification stage were adjusted to 3500 r / min, and the emulsification time was 12 min.

[0055] The obtained emulsion had a D50 of 0.40 μm; no stratification was observed after 3 months of acceleration, and the texture was relatively light and thin.

[0056] Comparative Example 1, in this comparative example, no glycoside nonionic emulsifier, phospholipid emulsifier and acrylic copolymer pre-hydration step was used, and the remaining steps were kept consistent as much as possible.

[0057] The preparation method was as follows: 6.00 wt% of medium-chain triglyceride, 2.00 wt% of shea butter, 1.00 wt% of hydrogenated vegetable oil and 1.00 wt% of cetyl stearyl alcohol were added to an oil phase tank, heated to 70℃ and stirred until completely melted. 2.50 wt% of PEG-100 stearate and 1.50 wt% of glycerol stearate SE were added, and stirring was continued at 70℃ and 400 r / min for 15 min to obtain an oil phase.

[0058] In the water phase tank, 5.00 wt% of glycerol, 2.00 wt% of butanediol, 1.00 wt% of pentanediol and 20 wt% of deionized water were added, and after stirring and dissolving, 0.20 wt% of carbomer was added and stirred for 15 min. Then, total snowbell glycoside, total glycyrrhiza glycoside and total sea buckthorn glycoside were added, and heated to 75℃ until dissolved uniformly.

[0059] The 75℃ oil phase was added to the 75℃ water phase in one portion and emulsified at 2000 r / min for 10 min. The heating was stopped and the temperature was allowed to cool naturally to 40℃, then triethanolamine was added to adjust the pH to 6.5, and then the temperature was cooled to 25℃, and water was added to make up to 100wt%.

[0060] The resulting emulsion had a uniform initial appearance, but after being placed at 45℃ for three months, slight creaming and particle size increase occurred; after centrifugation at 3000 r / min for 30 min, obvious layering occurred.

[0061] Performance testing: I. Test methods: 1. Particle size and particle size stability: the volume median particle size D50 of the emulsion at 25℃ was determined using a laser particle size analyzer. The particle size change was determined again after the sample was placed at room temperature and 45℃ for 3 months under accelerated conditions, respectively.

[0062] 2. Storage stability: the sample was stored at 45℃ for 3 months, during which the appearance, layering, creaming and color change were observed every month, and at the same time, centrifugation was carried out at 3000 r / min for 30 min, and whether layering occurred was recorded.

[0063] 3. Apparent viscosity: the apparent viscosity was determined at 25℃, shear rate 1 s -1 under the condition of 1 s -1, to evaluate the structural properties and skin feel matching of the system.

[0064] 4. Subjective evaluation of sensitive skin irritation: 30 volunteers with sensitive skin were selected, 0.2g of the sample was applied to the inner side of the forearm, and the discomfort such as stinging, burning and tightness within 10 min after application was recorded, and the score was graded as 0-3: 0 for no, 1 for mild, 2 for moderate, and 3 for obvious and difficult to tolerate, and the average score was calculated.

[0065] 5. Change in trans-epidermal water loss (TEWL): 20 volunteers with mild barrier damage were selected, and the products of Example 1 and Comparative Example 1 were applied to the cheeks of the face respectively, once a day in the morning and evening, for 4 weeks. The TEWL value was measured before use and at the end of the 4th week, and the relative percentage decrease was calculated.

[0066] 6. Bubble content and appearance uniformity: the emulsion was placed in a transparent measuring cylinder, and the initial volume V0 was recorded. After standing for 24 hours, the gas layer and the layering volume at the top of the emulsion were read, and the bubble volume fraction was calculated:

[0067] II. Test results: Table 2 Performance comparison of examples and comparative examples,

[0068] III. Analysis of results: As can be seen from Table 1, the emulsions of Examples 1-4 only have slight increase in median particle size after 3 months under accelerated conditions, and no obvious delamination and oiling-out phenomenon occurs, among which the particle size stability of Example 1 is the best. In contrast, the particle size of Comparative Example 1 obviously increases and delamination occurs after 3 months at 45℃, indicating that the conventional polyoxyethylene emulsification system has insufficient interface structure stability under the condition of total glycoside containing glycosides.

[0069] The apparent viscosity of Examples 1-4 is controlled in the range of 2000-5000 mPa·s, which can provide good structure support without producing heavy dragging feeling, and the average score of irritation feeling evaluated by volunteers is lower than 0.5, which is significantly lower than 1.4 of Comparative Example 1. It is indicated that the composite emulsification system composed of glycoside nonionic emulsifier, phospholipid and pre-hydrated acrylic acid copolymer can provide more gentle skin feeling for sensitive skin without using polyoxyethylene emulsifier and sulfate surfactant.

[0070] In terms of trans-epidermal water loss, the relative decrease amplitude of TEWL of Example 1 and Example 3 reaches 24% and 26% respectively, which is significantly higher than 12% of Comparative Example 1, indicating that the oil droplet structure formed by the composite emulsification system of the application and medium-chain triglyceride / solid lipid combination has more obvious positive effect on repairing and maintaining skin barrier.

[0071] In addition, Examples 1-4 are emulsified and cooled under reduced pressure, and the obtained emulsions all have bubble volume fraction lower than 1%, and the appearance is fine and the luster is uniform; Comparative Example 1 has significantly higher bubble volume fraction because it is not vacuum defoamed, and the surface is prone to depression and uneven luster after long-term storage.

[0072] It can be seen from the above results that the combination of total glycoside, glycoside nonionic emulsifier, phospholipid and specific acrylic acid copolymer, and the design of glycoside pre-dissolution, acrylic acid copolymer pre-hydration and reduced pressure emulsification process, can simultaneously realize significant improvement in active stability, interface structure stability and skin compatibility in sensitive skin care emulsion, and Example 1 is the preferred scheme, which shows the best particle size stability, the lowest irritation feeling and higher barrier repair effect.

[0073] The above only describes the preferred embodiments of the application, and the protection scope of the application is not limited to the above examples only, and any technical scheme falling within the idea of the application shall fall within the protection scope of the application. It should be noted that for ordinary skilled persons in the art, some improvements and refinements without departing from the principle of the application shall also be considered as the protection scope of the application.

Claims

1. A skincare lotion for sensitive skin based on a complex emulsification system, characterized in that, Included by weight percentage: A. 0.05–3.0% glycoside soothing component, wherein the glycoside soothing component is total glycosides derived from plants, and the mass fraction of glycoside compounds in the total glycosides is 50–95%; B. 3–20% oil phase components; C. A 1-7% complex emulsion system, wherein the complex emulsion system comprises: C1. 0.3-4.0% glycoside nonionic emulsifier, which is a C8-C16 alkyl polyglucoside or a mixture thereof; C2. 0.1–2.0% phospholipid emulsifier; C3. 0.1-2.0% acrylic copolymer emulsifier, which is a crosslinked copolymer obtained by copolymerizing acrylic acid with C10-C30 alkyl acrylates as monomers; D. 2-20% humectant, which is one or more polyols; E. The remainder is water; The mass ratio of the glycoside soothing component to the composite emulsification system is 1:4 to 40, the mass ratio of the glycoside nonionic emulsifier to the phospholipid emulsifier is 1:0.2 to 2, and the skin care lotion does not contain sulfate surfactants or polyoxyethylene nonionic emulsifiers.

2. The sensitive skin skin care lotion based on a composite emulsification system according to claim 1, characterized in that, The glycoside soothing component is a combination of total asiaticoside, total glycyrrhizin, and total sea buckthorn glycoside, wherein the total mass fraction of asiaticoside and hydroxyasiaticoside in the total asiaticoside is 30-80%.

3. The sensitive skin skincare lotion based on a composite emulsification system according to claim 1, characterized in that, The glycoside nonionic emulsifier is selected from decyl glucoside, decyl-octyl glucoside, cocoyl glucoside and mixtures thereof, and the average degree of glycosyl substitution of the glycoside nonionic emulsifier is 1.1 to 2.

5.

4. The sensitive skin skincare lotion based on a composite emulsification system according to claim 1, characterized in that, The acrylic copolymer emulsifier, after neutralization and hydration at 25°C and pH 5.0–6.2, forms a gel system, which can withstand a shear rate of 1 s. -1 The apparent viscosity at that time was 1000–6000 mPa·s.

5. The sensitive skin skincare lotion based on a composite emulsification system according to claim 1, characterized in that, The oil phase component includes medium-chain triglycerides and solid lipids, wherein the mass ratio of medium-chain triglycerides to solid lipids is 2 to 8:1, and the solid lipids are selected from one or more of shea butter, hydrogenated vegetable oil, and cetearyl alcohol.

6. A method for preparing a sensitive skin skin care lotion based on a composite emulsification system according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Glycoside pre-dissolution: Add the glycoside soothing component to water and humectant, stir at 20-35°C for 10-60 min to obtain glycoside pre-solution, wherein the mass ratio of the glycoside soothing component to the humectant is 1:3-20; (2) Prehydration of acrylic copolymer: Disperse acrylic copolymer emulsifier in water, add neutralizer to adjust pH to 5.0-6.2, and let stand for hydration at 20-35℃ for 60-180 min to obtain uniform acrylic copolymer gel; (3) Phospholipid oil phase premix: Mix the oil phase component with the phospholipid emulsifier and stir at 50-75°C until a homogeneous oil phase premix is ​​formed; (4) Aqueous premix: The glycoside presol obtained in step (1), the glycoside nonionic emulsifier, the acrylic copolymer gel obtained in step (2) and water are mixed and stirred at 50-75°C to obtain an aqueous premix. (5) Emulsification and cooling: At 50-75℃, the oil phase premix obtained in step (3) is slowly added to the aqueous phase premix obtained in step (4) at a shear speed of 3000-8000r / min and emulsified for 5-20min. After emulsification, the mixture is kept at 65-75℃ for 3-10min and then cooled to 25-35℃ under stirring to obtain a sensitive skin skin lotion.

7. The method for preparing a sensitive skin skincare lotion based on a composite emulsification system according to claim 6, characterized in that, In step (1), the mass concentration of the glycoside soothing component in the glycoside presol solution is 1–10 wt%.

8. The method for preparing a sensitive skin skincare lotion based on a composite emulsification system according to claim 6, characterized in that, In step (2), the mass ratio of acrylic copolymer to water is 1:20 to 80, and the neutralizing agent is selected from one or more of sodium hydroxide, potassium hydroxide and ammonia.

9. The method for preparing a sensitive skin skincare lotion based on a composite emulsification system according to claim 6, characterized in that, After emulsification in step (5), the median particle size D50 of the emulsion obtained is 0.2–3.0 μm.

10. The method for preparing a sensitive skin skincare lotion based on a composite emulsification system according to claim 6, characterized in that, The emulsification and cooling process in step (5) is carried out under reduced pressure, with an absolute system pressure of 20–80 kPa.

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