Mild amino acid facial cleanser and preparation method thereof

Abstract

The invention discloses a mild amino acid facial cleanser and a preparation method of the mild amino acid facial cleanser, and belongs to the technical field of daily cosmetics. A polar-nonpolar cleaning auxiliary agent composed of polyglycerol-10 laurate and isododecane, a double-complexing foam stabilizing system composed of sodium gluconate and sodium phytate, and a reversible network thickening system composed of xanthan gum and an acrylate cross-linked polymer are introduced; therefore, good cleaning power, foam maintenance under a hard water condition and viscosity stability are realized under the condition of relatively low surfactant consumption, and the problems of skin feeling and tightness during washing are solved.

Description

Technical Field

[0001] This invention belongs to the field of daily cosmetics technology, specifically relating to a mild amino acid facial cleanser and its preparation method. Background Technology

[0002] Facial cleansers are one of the basic skin care products, widely used for daily facial cleansing, removing makeup and sunscreen residue, and cleaning away oil, sweat, and environmental particles. With the increasing number of people with sensitive skin and damaged skin barriers, the market demand for gentle amino acid facial cleansers that are "low-irritant, low-tightening, have sufficient cleansing power, and produce fine foam" has increased significantly.

[0003] Existing amino acid facial cleansing systems mostly use mild surfactant combinations such as glutamate, sarcosinate, and betaine. However, in practical applications, the following contradictions often arise: increasing the surfactant content to enhance cleansing power and foam production can lead to a higher probability of tightness and stinging after rinsing; while reducing the surfactant content is gentler, it can easily result in insufficient oil removal, heavy residue, and thin foam. Furthermore, many amino acid systems react poorly in hard water (containing calcium). 2+ / Mg 2+ Under certain conditions, foam decay is significant, or viscosity drift, stratification, and low-temperature turbidity occur after the addition of salt / polyols or thickeners, resulting in a narrow formulation window and poor stability.

[0004] As consumers increasingly demand products that are suitable for sensitive skin and do not damage the skin barrier with long-term use, and given the stringent requirements of e-commerce channels regarding transportation, temperature fluctuations, and shelf-life stability, there is an urgent need for a gentle amino acid facial cleanser that can provide sufficient cleansing power, fine foam, and a pleasant rinsing feel even with low surfactant dosages, while maintaining stable viscosity and appearance in hard water and under varying temperature conditions. Failure to resolve these contradictions will lead to inconsistent product experiences, increased complaint rates, and batch instability risks. Summary of the Invention

[0005] This invention aims to solve the problem that existing amino acid facial cleansers are difficult to balance between "mildness, cleansing power, foam fineness, hard water compatibility and viscosity stability", especially: (1) insufficient cleansing power under the requirements of low irritation and low tightness; (2) foam decay and reduced stain removal under hard water conditions; (3) poor thickening stability (salt sensitivity, viscosity drift under temperature difference, low temperature turbidity / layering).

[0006] Therefore, the present invention provides a mild amino acid facial cleanser and its preparation method.

[0007] The objective of this invention can be achieved through the following technical solutions: This invention provides a mild amino acid facial cleanser, the key to which lies in constructing a "dual-function mild cleansing synergistic system + micro-complex foam stabilizing system + reversible network thickening system", specifically including: (1) Dual-function gentle cleaning synergistic system: It is based on amino acid anionic surfactants, combined with amphoteric surfactants and a small amount of nonionic surfactants, and introduces "polar-nonpolar cleaning aids" to enable the formula to maintain its ability to remove sebum / sunscreen film at a low active ingredient content, while reducing irritation and tightness.

[0008] A: Disodium Cocoyl Glutamate or Sodium Lauroyl Sarcosinate; B: Cocamidopropyl Betaine; C: Decyl Glucoside or Lauryl Glucoside; D: A polar-nonpolar synergistic cleaning agent formed by polyglyceryl-10 laurate and isododecane, wherein polyglyceryl-10 laurate improves the washability of the oil phase, and isododecane reduces stickiness and improves the dissolution efficiency of sunscreen oil film.

[0009] (2) Micro-complexed foam-stabilizing system: A dual complexing system of sodium gluconate and sodium phytate (in extremely low total amounts) was introduced into a mild formulation for hard water ion complexation, significantly reducing calcium content. 2+ / Mg 2+ Suppression of foaming and cleaning efficiency. Compared to single EDTA formulations, this system significantly improves foam retention in hard water at low addition levels, while also being less irritating to the skin and having better formulation compatibility.

[0010] (3) Reversible network thickening system: A composite thickening method using xanthan gum, acrylate crosspolymers (such as Acrylates / C10-30 AlkylAcrylate Crosspolymer), and aminomethylpropanol (AMP-95) for segmental neutralization is employed, with small amounts of glycerol and 1,3-propanediol added to control water activity. This system forms a network structure that is "weakly ionicly sensitive but reversibly recoverable": it can still restore uniform viscosity after storage temperature differences or transportation shocks, and it quickly breaks down during rinsing, improving the "easy-to-rinse and non-slippery" skin feel.

[0011] Specifically, the above-mentioned mild amino acid facial cleanser comprises, by weight percentage: Amino acid anionic surfactants: 8.0%–12.0%; Amphoteric surfactants: 2.0%–5.0%; Nonionic surfactants: 0.5%–4.0%; Polar-nonpolar cleaning aids: 0.2%–2.5% (of which polyglycerol-10 laurate 0.1%–1.5% and isododecane 0.1%–1.0%); Complexed foam stabilizing system: 0.05%–0.50% (sodium gluconate 0.03%–0.30%, sodium phytate 0.02%–0.20%); Composite thickening system: 0.10%~1.20% (xanthan gum: 0.05%~0.60%, acrylate crosslinking polymer: 0.05%~0.60%); Moisturizer: Glycerin 1.0%–6.0%; Solvent: 1,3-propanediol 1.0%–6.0%; Preservatives: 0.2%–1.2%; Soothing agents: panthenol 0.05%–0.5%, allantoin 0.05%–0.3%; pH adjuster: Aminomethylpropanol (AMP-95) 0.05%~0.50%; Balance: Add deionized water to bring the total to 100%.

[0012] Note: The above raw materials are all commonly used commercial raw materials in daily chemical products and can be purchased from common suppliers (INCI name is universal).

[0013] Furthermore, the preparation method of the above-mentioned mild amino acid facial cleanser includes the following steps: Step S1: Aqueous phase preparation: Add 70% to 80% of the formula amount of deionized water to the main pot, start stirring (200 to 400 rpm), add glycerol and 1,3-propanediol, stir for 10 to 30 minutes until clear and homogeneous, then add xanthan gum, stir for 20 to 30 minutes until there is no obvious agglomeration, then add sodium gluconate and sodium phytate, stir for 10 to 30 minutes; Step S2: Add polymer thickener and pre-neutralize: Add acrylate cross-linked polymer (such as Acrylates / C10-30 Alkyl Acrylate Crosspolymer) to the main pot at 25-35°C to avoid clumping, and then add 50%-70% of AMP-95 for pre-neutralization. Stir for 20-30 minutes to form the basic viscosity. Step S3: Adding the surfactant system (low-foaming process): Add amino acid anionic surfactant, amphoteric surfactant, and nonionic surfactant to the main pot in sequence. Control the stirring speed at 100-250 rpm to avoid a large amount of air entrainment. Stir for 20-30 minutes until the system is homogeneous. Step S4: Cleaning aids and post-addition: Mix polyglycerol-10 laurate and isododecane in a water bath at 40-45°C for 10-20 minutes to obtain a premix. Add the premix to the main pot and stir for 15-30 minutes. Then add the preservative, panthenol, and allantoin to the main pot in sequence and stir for 10-20 minutes. Step S5: Final adjustment and filling: Add the remaining AMP-95 to the main pot; add deionized water to make up to 100%, stir at low speed to defoam for 20-30 minutes, filter with 80-120 mesh and fill to obtain a mild amino acid facial cleanser.

[0014] The beneficial effects of this invention are: This invention provides a mild amino acid facial cleanser. By constructing a "dual-function mild cleansing synergistic system," a "micro-complex foam-stabilizing system," and a "reversible network thickening system," it effectively solves the technical problems of existing amino acid facial cleansers, such as insufficient cleansing power under low-irritation conditions, severe foam attenuation under hard water conditions, and poor stability of the thickening system (e.g., viscosity drift due to temperature difference, slippery feeling). Specific beneficial effects and principle analysis are as follows: (1) Significantly improved cleaning ability and rinsing feel under low surfactant system, resolving the contradiction between gentleness and cleanliness: The present invention achieves excellent oil removal effect (oil removal rate of soft water 91.5% to 98.2%) and refreshing rinsing feel even with a relatively low amount of surfactant (Examples 1-3). This is mainly due to the synergistic effect of "polar-nonpolar cleaning aids".

[0015] Principle Analysis: Based on the comparative data of Example 2 and Comparative Example 1, after removing polyglycerol-10 laurate and isododecane, the oil removal rate of soft water decreased significantly from 96.8% to 75.4%, proving that this auxiliary agent system is key to improving cleaning power. Further analysis of Comparative Example 3, where only polyglycerol ester was retained and isododecane was removed, resulted in an oil removal rate of 82.3%, indicating that isododecane, as a non-polar solvent, plays a decisive role in dissolving stubborn sebum and sunscreen film. Analysis of Comparative Example 2, where only isododecane was retained and polyglycerol ester was removed, although the oil removal rate (88.5%) was acceptable, the coefficient of friction on the wetted surface decreased from 0.65 to 0.45, and a small amount of floating oil appeared after centrifugation. This indicates that polyglycerol-10 laurate played a crucial emulsifying and solubilizing role in the system, helping the oil phase to be carried away by water and avoiding the "residual oil film" feeling caused by a simple solvent. Therefore, this invention achieves excellent cleaning power and residue-free rinsing through a specific ratio of the two components.

[0016] (2) Excellent hard water adaptability ensures foaming and cleaning efficiency under harsh water conditions: This invention introduces a double complexation foam stabilizing system composed of sodium gluconate and sodium phytate, which significantly overcomes the inhibition of amino acid surfactants by hard water.

[0017] Principle Analysis: Based on the comparison between Example 2 and Comparative Example 4, after removing the complexing system, the foam retention rate under hard water (200 mg / L) conditions plummeted from 89.2% to 56.6%, and the hard water degreasing rate also decreased from 94.5% to 76.8%, with a soapy residue feeling after rinsing. This indicates that calcium and magnesium ions severely interfere with the formation of surfactant micelles. Further comparison between Example 2 and Comparative Examples 5 and 6 shows that when sodium phytate or sodium gluconate is used alone, the hard water foam retention rate (81.1% and 80.2%, respectively) is lower than that of Example 2 (89.2%), which uses a two-component compound. This indicates that sodium gluconate and sodium phytate have a synergistic effect when complexing metal ions of different valence states or types, and can more comprehensively shield against hard water ion interference, thus maintaining foam richness and cleaning efficiency at extremely low addition levels (0.05%–0.50%).

[0018] (3) It achieves an excellent balance between viscosity stability and sensory experience, and solves the problems of thickening difficulty and slippery texture: The present invention adopts a composite thickening system composed of xanthan gum and acrylate crosslinked polymers, which successfully solves the common problems of "salt sensitivity" and "slippery texture" in amino acid facial cleansers.

[0019] Principle Analysis: Based on the comparison between Example 2 and Comparative Example 8, if xanthan gum is removed and only acrylic polymers are used, although the initial viscosity is acceptable, after high and low temperature cycling (-5℃ to 45℃), the viscosity change rate is as high as -35.3%, and the appearance becomes thinner and slightly cloudy. This indicates that a single acrylic polymer cannot withstand the ionic strength and temperature difference changes of the amino acid system. Conversely, according to Comparative Example 9, if only xanthan gum is used, although the viscosity stability is better (change rate -3.3%), the washing friction coefficient is as low as 0.35, exhibiting a severe "false slippery" feeling, and the appearance is cloudy.

[0020] Synergistic Effect: Example 2, employing a composite system, showed a viscosity decrease of only 2.9% after high and low temperature cycling, maintaining a uniform appearance and a coefficient of friction of 0.65 (clean and non-drying). This indicates that xanthan gum provides a rigid, salt-resistant framework, ensuring stability under extreme conditions; while the acrylic polymer provides thixotropy, improving the colloidal rheological properties of xanthan gum, allowing it to quickly "break down" during rinsing and avoiding a slippery feel. The two complement each other, achieving a dual optimization of product shelf-life stability and user experience.

[0021] In summary, through the precise combination of its components, this invention powerfully demonstrates, on a data level, its significant advancements over existing technologies in terms of cleaning power, foam stability in hard water, and formulation stability. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Furthermore, unless otherwise specified, the raw materials, reagents, or devices used in the following embodiments can be obtained from conventional commercial channels or by existing known methods.

[0023] Example 1

[0024] A mild amino acid facial cleanser and its preparation method: First, the gentle amino acid facial cleanser comprises, by weight percentage: Sodium lauroyl sarcosinate: 8.0%; Cocamidopropyl betaine: 2.0%; Lauryl glucoside: 0.5%; Polyglycerol-10 laurate: 0.1%; Isododecane: 0.1%; Sodium gluconate: 0.03%; Sodium phytate: 0.02%; Xanthan gum: 0.05%; Acrylates / C10-30 Alkyl Acrylate Crosspolymer: 0.05%; Glycerin: 1.0%; 1,3-Propanediol: 1.0%; Preservative phenoxyethanol: 0.2%; Panthenol: 0.05%; Allantoin: 0.05%; AMP-95: 0.05%; Deionized water: Top up to 100%.

[0025] Then, the preparation method of the above-mentioned mild amino acid facial cleanser includes the following steps: First, weigh each raw material according to its mass percentage; Step S1: Aqueous phase preparation: Add 70% of the formula amount of deionized water to the main pot, start stirring (200 rpm), add glycerol and 1,3-propanediol, stir for 10 min until clear and homogeneous, then add xanthan gum, stir for 20 min until there is no obvious agglomeration, then add sodium gluconate and sodium phytate, stir for 10 min. Step S2: Add polymer thickener and pre-neutralize: Add acrylate crosspolymer (Acrylates / C10-30 Alkyl Acrylate Crosspolymer) to the main pot at 25°C to prevent clumping, then add 50% of AMP-95 for pre-neutralization and stir for 20 minutes to form the basic viscosity. Step S3: Adding the surfactant system (low-foaming process): Add the amino acid anionic surfactant sodium lauroyl sarcosinate, the amphoteric surfactant cocamidopropyl betaine, and the nonionic surfactant lauryl glucoside to the main pot in sequence. Control the stirring speed at 100 rpm to avoid a large amount of air entrainment. Stir for 20 minutes until the system is homogeneous. Step S4: Cleaning aids and post-addition: Mix polyglycerol-10 laurate and isododecane in a 40°C water bath for 10 min to obtain a premix. Add the premix to the main pot and stir for 15 min. Then add the preservatives phenoxyethanol, panthenol, and allantoin to the main pot in sequence and stir for 10 min. Step S5: Final adjustment and filling: Add the remaining AMP-95 to the main pot; add deionized water to make up to 100%, stir at low speed to defoam for 20 minutes, filter with 80 mesh and fill to obtain a mild amino acid facial cleanser.

[0026] Example 2

[0027] A mild amino acid facial cleanser and its preparation method: First, the gentle amino acid facial cleanser comprises, by weight percentage: Disodium cocoyl glutamate: 10.0%; Cocamidopropyl betaine: 4.5%; Decyl glucoside: 3.0%; Polyglycerol-10 laurate: 1.0%; Isododecane: 0.5%; Sodium gluconate: 0.20%; Sodium phytate: 0.10%; Xanthan gum: 0.45%; Acrylates / C10-30 Alkyl Acrylate Crosspolymer: 0.35%; Glycerin: 4.0%; 1,3-Propanediol: 3.5%; Preservative phenoxyethanol: 1.0%; Panthenol: 0.35%; Allantoin: 0.20%; AMP-95: 0.30%; Deionized water: Top up to 100%.

[0028] Then, the preparation method of the above-mentioned mild amino acid facial cleanser includes the following steps: Step S1: Aqueous phase preparation: Add 70% of the formula amount of deionized water to the main pot, start stirring (400 rpm), add glycerol and 1,3-propanediol, stir for 30 min until clear and homogeneous, then add xanthan gum, stir for 30 min until there is no obvious agglomeration, then add sodium gluconate and sodium phytate, stir for 30 min. Step S2: Add polymer thickener and pre-neutralize: Add acrylate crosspolymer (Acrylates / C10-30 Alkyl Acrylate Crosspolymer) to the main pot at 35°C to prevent clumping, then add 70% of AMP-95 for pre-neutralization and stir for 30 minutes to form the basic viscosity. Step S3: Adding the surfactant system (low-foaming process): Add the amino acid anionic surfactant disodium cocoyl glutamate, the amphoteric surfactant cocamidopropyl betaine, and the nonionic surfactant decyl glucoside to the main pot in sequence. Control the stirring speed at 250 rpm to avoid a large amount of air entrainment. Stir for 30 minutes until the system is homogeneous. Step S4: Cleaning aids and post-addition: Polyglycerol-10 laurate and isododecane are mixed in a 45°C water bath for 20 minutes to obtain a premix. The premix is ​​added to the main pot and stirred for 30 minutes. Then, the preservatives phenoxyethanol, panthenol, and allantoin are added to the main pot in sequence and stirred for 20 minutes. Step S5: Final adjustment and filling: Add the remaining AMP-95 to the main pot; add deionized water to make up to 100%, stir at low speed to defoam for 30 minutes, filter through 120 mesh and fill to obtain a mild amino acid facial cleanser.

[0029] Example 3

[0030] A mild amino acid facial cleanser and its preparation method: First, the gentle amino acid facial cleanser comprises, by weight percentage: Disodium cocoyl glutamate: 12.0%; Cocamidopropyl betaine: 5.0%; Decyl glucoside: 4.0%; Polyglycerol-10 laurate: 1.5%; Isododecane: 1.0%; Sodium gluconate: 0.30%; Sodium phytate: 0.20%; Xanthan gum: 0.60%; Acrylates / C10-30 Alkyl Acrylate Crosspolymer: 0.60%; Glycerin: 6.0%; 1,3-Propanediol: 6.0%; Preservative phenoxyethanol: 1.2%; Panthenol: 0.5%; Allantoin: 0.3%; AMP-95: 0.50%; Deionized water: Top up to 100%.

[0031] Then, the preparation method of the above-mentioned mild amino acid facial cleanser includes the following steps: Step S1: Aqueous phase preparation: Add 80% of the formula amount of deionized water to the main pot, start stirring (400 rpm), add glycerol and 1,3-propanediol, stir for 30 min until clear and homogeneous, then add xanthan gum, stir for 30 min until there is no obvious agglomeration, then add sodium gluconate and sodium phytate, stir for 30 min. Step S2: Add polymer thickener and pre-neutralize: Add acrylate crosspolymer (Acrylates / C10-30 Alkyl Acrylate Crosspolymer) to the main pot at 35°C to prevent clumping, then add 70% of AMP-95 for pre-neutralization and stir for 30 minutes to form the basic viscosity. Step S3: Adding the surfactant system (low-foaming process): Add the amino acid anionic surfactant disodium cocoyl glutamate, the amphoteric surfactant cocamidopropyl betaine, and the nonionic surfactant decyl glucoside to the main pot in sequence. Control the stirring speed at 250 rpm to avoid a large amount of air entrainment. Stir for 30 minutes until the system is homogeneous. Step S4: Cleaning aids and post-addition: Polyglycerol-10 laurate and isododecane are mixed in a 45°C water bath for 20 minutes to obtain a premix. The premix is ​​added to the main pot and stirred for 30 minutes. Then, the preservatives phenoxyethanol, panthenol, and allantoin are added to the main pot in sequence and stirred for 20 minutes. Step S5: Final adjustment and filling: Add the remaining AMP-95 to the main pot; add deionized water to make up to 100%, stir at low speed to defoam for 30 minutes, filter through 120 mesh and fill to obtain a mild amino acid facial cleanser.

[0032] Comparative Example 1 Comparative Example 1 served as the control group for Example 2. Based on Example 2, polyglycerol-10 laurate and isododecane were removed and replaced with an equal amount of deionized water, while the rest remained unchanged, resulting in a mild amino acid facial cleanser.

[0033] Comparative Example 2 Comparative Example 2 served as the control group for Example 2. Based on Example 2, 1.0% of polyglycerol-10 laurate was removed, and isododecane was increased to 1.5%, while the rest remained unchanged, resulting in a mild amino acid facial cleanser.

[0034] Comparative Example 3 Comparative Example 3 served as the control group for Example 2. Based on Example 2, 0.5% of isododecane was removed, and polyglycerol-10 laurate was increased to 1.5%, while the rest remained unchanged, resulting in a mild amino acid facial cleanser.

[0035] Comparative Example 4 Comparative Example 4 served as the control group for Example 2. Based on Example 2, sodium gluconate and sodium phytate were removed and replaced with deionized water, while the rest remained unchanged, resulting in a mild amino acid facial cleanser.

[0036] Comparative Example 5 Comparative Example 5 served as the control group for Example 2. Based on Example 2, 0.20% of sodium gluconate was removed, and sodium phytate was increased to 0.30% (keeping the total amount of complexing agent unchanged at 0.30%), while the rest remained unchanged, resulting in a mild amino acid facial cleanser.

[0037] Comparative Example 6 Comparative Example 6 served as the control group for Example 2. Based on Example 2, 0.10% of sodium phytate was removed, and sodium gluconate was increased to 0.30% (keeping the total amount of complexing agent unchanged at 0.30%), while the rest remained unchanged, resulting in a mild amino acid facial cleanser.

[0038] Comparative Example 7 Comparative Example 7 served as the control group for Example 2. Based on Example 2, xanthan gum and acrylate cross-linked polymers were removed and replaced with deionized water, while the rest remained unchanged, resulting in a mild amino acid facial cleanser.

[0039] Comparative Example 8 Comparative Example 8 served as the control group for Example 2. Based on Example 2, 0.45% of xanthan gum was removed, and the acrylate crosslinking polymer was increased to 0.80% (while keeping the total thickener content unchanged at 0.80%), with the rest remaining the same, resulting in a mild amino acid facial cleanser.

[0040] Comparative Example 9 Comparative Example 9 served as the control group for Example 2. Based on Example 2, 0.35% of the acrylate crosslinking polymer was removed, and the xanthan gum content was increased to 0.80% (while keeping the total thickener content unchanged at 0.80%). The rest remained the same, resulting in a mild amino acid facial cleanser.

[0041] Comparative Example 1 Performance testing methods and results: (1) Sample preparation and conditions: Samples of amino acid facial cleansers prepared in Examples 1-3 and Comparative Examples 1-9 were allowed to stand for 24 hours to defoam; the test temperature was 25±1℃, and n=3 were used for each test, and the average value was taken.

[0042] (2) pH and viscosity: pH test: Take 10g of sample, add 10g of deionized water, mix well, and measure with a calibrated pH meter; Viscosity test: Brookfield viscometer (RV), rotor #4, 20 rpm, 25℃, take the reading after it stabilizes.

[0043] result:

[0044] (3) Hard water foam retention capacity: Hard water preparation: Hardness of 200 mg / L (calculated as CaCO3): Prepared using calcium chloride and magnesium sulfate, so that the CaCO3 content is reduced to a certain level. 2+ :Mg 2+ =2:1 (molar ratio), and bring to volume with deionized water.

[0045] Test solution: Prepare a sample active ingredient equivalent to 0.5% (based on the finished product mass and kept consistent).

[0046] Procedure: Measure 200 mL of test solution into a graduated cylinder; use a standard drop liquid to form foam (drop distance 90 cm), record the foam height H0 at 0 min; let stand for 5 min and record H5; record H at 10 min. 10 Evaluation metric: Foam retention rate = H 10 / H0×100%.

[0047] Results (hard water 200 mg / L):

[0048] (4) Degreasing and cleaning power: Artificial sebum formulation (commercially available or homemade; homemade formulation is provided here): Squalane / Isopropyl myristate / Oleic acid = 50 / 30 / 20 (mass ratio).

[0049] Substrate: Standard PMMA board or glass board (50mm×50mm), first cleaned with ethanol, dried and weighed m0.

[0050] Oiling: Apply 0.200g of artificial sebum evenly to the plate, let it stand for 30 minutes, and then weigh it (m1).

[0051] Cleaning steps: Prepare a 10% finished product solution (10g sample + 90g water; water can be either soft or hard water); immerse the plate in the solution and wipe it 20 times with a standard sponge under a 200g load; rinse with running tap water for 10 seconds and air dry at room temperature for 30 minutes; weigh m2. Oil removal rate = (m1-m2) / (m1-m0) × 100%.

[0052] result:

[0053] (5) Objective alternative evaluation of rinsing residue / "false slippery feeling": Instead of using instrumental microscopic characterization, the "wet friction coefficient" of reproducible experiments is used as an objective substitute indicator for rinsing residue (a simple friction coefficient test stand or a commercially available friction coefficient measuring instrument can be used; if no instrument is available, weights and a tension gauge can be used to set it up).

[0054] Steps: After cleaning and rinsing the artificial grease plate according to step (4), add 5 mL of deionized water to the plate surface to form a wet surface; apply a normal load of 500 g to the standard rubber sheet (20 mm × 20 mm) and pull it at a uniform speed of 100 mm / min, and record the average pulling force F; the coefficient of friction μ = F / (load × g) (can be directly approximated by F / load). Judgment: The lower the μ, the more "slippery / film-like" it is, which usually means that the rinsing residue or false slippery feeling is more obvious.

[0055] Result (expressed in μ):

[0056] (6) Viscosity stability: High and low temperature cycling: -5℃ / 24h→45℃ / 24h is one cycle, for a total of 3 cycles; after resting at 25℃ for 24h, the viscosity and appearance are measured.

[0057] Centrifugation: Take 50 mL of sample, centrifuge at 3000 rpm for 30 min, and observe the layering / precipitation / obvious bubble layer.

[0058] result:

[0059] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A mild amino acid facial cleanser, characterized in that, Included by weight percentage: Amino acid anionic surfactants: 8.0%–12.0%; Amphoteric surfactants: 2.0%–5.0%; Nonionic surfactants: 0.5%–4.0%; Polar-nonpolar cleaning aids: 0.2%–2.5%; Complexed foam stabilizing system: 0.05%~0.50%; Composite thickening system: 0.10%~1.20%; Glycerin: 1.0%–6.0%; 1,3-Propanediol: 1.0%–6.0%; Phenoxyethanol: 0.2%–1.2%; Panthenol: 0.05%–0.5%; Allantoin: 0.05%–0.3%; Aminomethylpropanol: 0.05%–0.50%; The remainder is deionized water; The composite thickening system consists of xanthan gum and acrylate crosslinking polymers.

2. The mild amino acid facial cleanser according to claim 1, characterized in that, The amino acid anionic surfactant is disodium cocoyl glutamate or sodium lauroyl sarcosinate.

3. The mild amino acid facial cleanser according to claim 1, characterized in that, The nonionic surfactant is decyl glucoside or lauryl glucoside.

4. The mild amino acid facial cleanser according to claim 1, characterized in that, The polar-nonpolar cleaning aid consists of polyglycerol-10 laurate and isododecane.

5. A mild amino acid facial cleanser according to claim 1, characterized in that, The complexed foam-stabilizing system consists of sodium gluconate and sodium phytate.

6. A method for preparing a mild amino acid facial cleanser according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step S1: Add 70% to 80% of the formula amount of deionized water to the main pot, start stirring, add glycerin and 1,3-propanediol, stir for 10 to 30 minutes, then add xanthan gum, stir for 20 to 30 minutes, then add the complexing foam stabilizing system, stir for 10 to 30 minutes. Step S2: Add 50% to 70% of the amount of acrylate crosslinking polymer and aminomethylpropanol to the main pot at 25 to 35°C, and stir for 20 to 30 minutes; Step S3: Add amino acid anionic surfactant, amphoteric surfactant, and nonionic surfactant to the main pot in sequence, and stir for 20-30 minutes; Step S4: Add the polar-nonpolar cleaning aid to the main pot and stir for 15-30 minutes; then add phenoxyethanol, panthenol, and allantoin to the main pot in sequence and stir for 10-20 minutes. Step S5: Add the remaining aminomethylpropanol to the main pot, add deionized water to make up to 100%, stir and defoam for 20-30 minutes, filter with 80-120 mesh and fill to obtain a mild amino acid facial cleanser.

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