Composition for skin cleaning and application thereof

Abstract

The invention discloses a composition for skin cleaning and application thereof, and belongs to the field of daily chemicals. The composition comprises glycolipid and a lauryl alcohol polyether carboxylic acid surfactant in a specific weight ratio. Wherein the glycolipid is preferably sophorolipid, and the lauryl alcohol polyether carboxylic acid surfactant is preferably lauryl alcohol polyether-5 carboxylic acid. According to the composition disclosed by the invention, the cleaning efficiency on unsaturated fatty acids (such as oleic acid and squalene) on the skin surface is remarkably improved on the premise of not excessively adding a high-effect anionic surfactant or sacrificing the product mildness. Meanwhile, the composition can effectively reduce degeneration damage to skin keratoprotein, has good skin mildness and safety, and is suitable for washing-off type personal care products for face cleaning, hair washing, bathing and the like.

Description

Technical Field

[0001] This invention relates to the field of daily chemical products technology, and more specifically to a composition for skin cleansing and its application. Background Technology

[0002] Sebum secreted by the skin contains a large amount of unsaturated fatty acids, such as squalene and oleic acid. These lipids are crucial for maintaining the skin barrier function. However, due to the unsaturated bonds in their chemical structure, unsaturated fatty acids are easily oxidized by air, generating oxidation products and free radicals. This can trigger skin inflammation and oxidative stress damage, causing or exacerbating skin problems such as dandruff and acne. Therefore, an ideal wash-off personal care product should not only remove dust and dirt but also effectively cleanse unsaturated fatty acids.

[0003] Currently available cleansing products typically rely on surfactant systems. Conventional anionic surfactants (such as sodium lauryl ether sulfate, SLES) have good cleaning power for unsaturated fatty acids, but they are highly irritating and may damage the skin barrier with long-term use. To reduce irritation and improve system viscosity, milder zwitterionic surfactants (such as cocamidopropyl betaine, CAPB) are often added to the formulation. However, zwitterionic surfactants generally have weak cleaning ability for unsaturated fatty acids, and their excessive addition can significantly weaken the overall cleaning effect of the formulation on the target lipids.

[0004] To address the aforementioned contradictions, existing technologies have attempted several methods: First, reducing or avoiding the use of nonionic surfactants, but this sacrifices the thickening and mildness of the system, leading to poorer formulation stability; Second, adding specific emulsifiers (such as polyglycerol-10 myristate) to enhance the emulsification and cleansing of lipids, but this method often inhibits product foaming and may over-cleanse the structural lipids between skin cells, which is also detrimental to skin health.

[0005] Therefore, there is an urgent need in this field to develop a new technical solution that can effectively improve the ability to clean unsaturated fatty acids on the skin surface while maintaining good foaming properties, gentleness, and formula stability. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a novel skin cleansing composition. Through the synergistic effect of specific components, this composition can significantly improve the cleansing efficiency of unsaturated fatty acids (especially oleic acid and squalene) while ensuring the product's gentleness and pleasant user experience.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: On the one hand, the present invention provides a composition for skin cleansing comprising glycolipid and lauryl ether carboxylic acid surfactant, wherein the mass ratio of glycolipid to lauryl ether carboxylic acid surfactant is 3:1 to 1:3, and within this ratio range, the two exhibit the best synergistic effect.

[0008] Furthermore, the glycolipid is preferably sophorolipid. Sophorolipid is a naturally derived biosurfactant with excellent surface activity and biocompatibility.

[0009] Furthermore, the lauryl polyether carboxylic acid surfactant refers to a carboxylic acid or carboxylate surfactant obtained by ethoxylation and carboxymethylation of lauryl alcohol and ethylene oxide. More preferably, the lauryl polyether carboxylic acid surfactant is lauryl polyether-5 carboxylic acid. Lauryl polyether carboxylic acid combines the cleaning power of anionic surfactants with the mildness provided by the polyether chain, making it a mild anionic / amphoteric modified surfactant.

[0010] The compositions of the present invention may further comprise anionic surfactants conventional in the art to provide basic cleaning power and rich foam. Exemplary anionic surfactants include, but are not limited to, sodium lauryl ether sulfate (SLES), sodium lauryl sulfate (SLS), sodium cocoyl methyl taurate, etc.

[0011] The compositions of the present invention may further comprise zwitterionic surfactants to further enhance the mildness and viscosity of the system. Exemplary zwitterionic surfactants include, but are not limited to, cocamidopropyl betaine (CAPB), sodium lauroamphoacetate, and disodium cocoamphodiacetate.

[0012] The compositions of the present invention are typically formulated into aqueous systems and can be used to make various wash-off personal care products, such as facial cleansers, shampoos, shower gels, hand soaps, etc.

[0013] On the other hand, the present invention provides the use of the above composition in the preparation of wash-off personal care products for cleansing skin with unsaturated fatty acids. The unsaturated fatty acids are preferably oleic acid and / or squalene.

[0014] In another aspect, the present invention provides the use of the above composition in the preparation of wash-off personal care products with reduced skin irritation.

[0015] The beneficial effects and principles of this invention: Through in-depth research, this invention has discovered that combining a specific ratio of glycolipids (especially sophorolipids) with lauryl polyether carboxylic acid surfactants (especially lauryl polyether-5 carboxylic acid) can produce a significant synergistic effect. The mechanism is as follows: Synergistic Solubilization and Emulsification: Sophorolipids, a biosurfactant with a low critical micelle concentration, possess a unique molecular structure with long hydrophobic chains and strongly hydrophilic sugar rings, exhibiting strong emulsifying and solubilizing capabilities for highly hydrophobic lipids (such as unsaturated fatty acids). Lauryl ether-5 carboxylic acid, with its polyoxyethylene ether chain and carboxylic acid group, has a spatial structure and charge distribution that helps disrupt the adhesion between sebum and the stratum corneum. When combined, the two form a complementary micelle structure, jointly solubilizing and emulsifying more unsaturated fatty acid molecules, making them easier to detach from the skin surface and rinse away with water.

[0016] Reduced irritation: Sophorolipids themselves possess excellent mildness and anti-inflammatory properties. Lauryl ether-5-carboxylic acid is also milder than traditional strong anionic surfactants (such as SLES). The combination of these two ingredients allows the entire cleansing system to effectively remove oil while significantly reducing the denaturing effect on skin keratin proteins (as shown in the protein denaturation rate data in the examples), thereby improving the product's skin safety.

[0017] Overcoming the shortcomings of zwitterionic surfactants: In systems containing conventional zwitterionic surfactants (such as CAPB), the direct addition of the glycolipid-lauryl alcohol polyether carboxylic acid combination of the present invention can effectively compensate for the weak cleaning power of zwitterionic surfactants without significantly changing the viscosity and foaming properties of the system, thereby achieving targeted and efficient cleaning of unsaturated fatty acids.

[0018] Experimental data (see detailed embodiments) strongly demonstrate the beneficial effects of the present invention: formulations containing the core combination of the present invention (glycolipids and lauryl ether-5-carboxylic acid) (such as Examples 10-18) exhibited significantly higher oleic acid washing rates than comparative formulations (such as Comparative Examples 1-9) that did not contain this combination or contained only a single component, and the washing rate for squalene was also maintained at an extremely high level. Simultaneously, these formulations generally showed lower protein denaturation rates (reflecting irritation), indicating their good mildness.

[0019] In summary, the composition of the present invention successfully resolves the contradiction between cleansing effectiveness and gentleness in the prior art, and provides a highly efficient, gentle, and targeted solution for cleansing unsaturated fatty acids in the skin. Attached Figure Description

[0020] Figure 1 These are sample images of Example 11 (left) and Example 12 (right).

[0021] Figure 2The hair condition after washing is shown for Comparative Example 2 (left), Comparative Example 8 (middle), and Example 14 (right). Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but this should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art, and the materials, reagents, etc. used in the following embodiments are commercially available unless otherwise specified.

[0023] Preparation of compositions in Examples 10-18 and Comparative Examples 1-9 Weigh each raw material according to the formulation shown in Table 1 (weight percentage, based on active ingredient content), with the remainder being water. Add deionized water to a suitable container, and while stirring, add each surfactant component in Table 1 in sequence, as well as glycolipids and lauryl ether-5 carboxylic acid as needed. Continue stirring until all components are completely dissolved and the system is homogeneous and transparent, thus obtaining the clean composition samples of each example and comparative example.

[0024] Table 1: Composition of Examples 10-18 and Comparative Examples 1-9 (Unit: wt%, active ingredient content) Examples 10-18 contain a combination of the core glycolipid (sophorolipid) and lauryl ether-5 carboxylic acid, with the proportions falling within the preferred range. Comparative Examples 1-9 are control samples that do not contain the core combination or contain only one of them.

[0025] Performance testing Oleic acid cleaning rate test: Take a standard hair strand and place it in a constant temperature and humidity chamber at 40℃ and 45% relative humidity for 2 hours. Remove and weigh the strand, recording the initial weight as m1. Apply 0.3g of oleic acid evenly to the hair strand and record the oleic acid weight as m2. Place the strand back in the chamber and treat it under the same conditions for 2 hours. Remove the strand and clean it with 0.7g of the test sample, then rinse thoroughly with water. Dry the cleaned hair strand at 40℃ and 45% relative humidity for 2 hours, weigh it, and record the final weight as m3. The oleic acid cleaning rate is calculated as follows: Cleaning rate (%) = [1 - (m3 - m1) / m2] × 100%. Each sample is tested in triplicate, and the average value is taken as the average oleic acid cleaning rate.

[0026] Squalene washing efficiency test: The test method is the same as the oleic acid cleaning rate test, except that the coating is replaced with an equal amount of squalene instead of oleic acid.

[0027] Protein denaturation rate test (mildness assessment): Prepare a 1% aqueous solution of the sample to be tested. Take a certain amount of this solution, add 0.5g of zein, and sonicate for 30 minutes to ensure sufficient dispersion and possible dissolution of the protein. Then filter, and measure the absorbance (OD value) of the filtrate at 470nm wavelength using a UV-Vis spectrophotometer. The higher the absorbance value, the more zein has been dissolved, indicating a stronger denaturing effect of the sample on the protein, and thus a greater potential for skin irritation.

[0028] Results analysis: Cleaning Efficiency: As shown in Table 2, Comparative Example 1, containing only the strong anionic surfactant SLES, showed acceptable cleaning rates for oleic acid and squalene (75.34%, 99.87%), but its high protein denaturation rate (0.585) indicated strong irritation. Comparative Examples 2-4, containing only amphoteric surfactants, showed extremely low or even negative oleic acid cleaning rates (meaning ineffective cleaning or even residue buildup; the surfactants formed a water-in-oil emulsion with oleic acid and rinsing water, resulting in an overall hydrophobic environment). Figure 2 As shown in the image, because the rinsing water was encapsulated in oleic acid, the moisture could not be dried during the drying process, and the entire hair stuck to the surface, confirming the inherent defects of zwitterionic surfactants in cleaning unsaturated fatty acids.

[0029] Comparative examples 5-7 combined SLES and a single zwitterionic surfactant, and although the oleic acid cleaning rate was improved, it was still not ideal (8.83%-38.01%).

[0030] Comparative Examples 8 and 9 used lauryl ether-5 carboxylic acid or sophoryl ester alone, respectively. Although their oleic acid cleaning rates (71.48% and 69.84%) were better than most zwitterionic systems, they were lower than the core combination of the present invention.

[0031] Table 2 Performance Test Results Effects of the Invention: Examples 10-18, which contain both sophorolipids and lauryl ether-5-carboxylic acid, exhibit superior performance. Oleic acid cleaning rates generally reached over 80%, with a maximum of 92.06% (Example 10), significantly higher than all comparative examples. Simultaneously, the cleaning rate for squalene remained at a high level of over 97%. More importantly, the protein denaturation rates (absorbance 0.089-0.391) in these examples were generally lower than or comparable to the mildest formulation in the comparative examples, indicating that the invention achieves highly efficient degreasing while maintaining excellent gentleness. In particular, Examples 10-12, while achieving highly efficient cleaning (oleic acid cleaning rate 84%-93%), exhibited extremely low protein denaturation rates (absorbance 0.089-0.102), achieving an optimal balance between cleaning power and gentleness.

[0032] In summary, the technical solution of the present invention, through a specific combination of glycolipids and lauryl ether carboxylic acid surfactants, successfully provides an innovative composition that can effectively and gently cleanse the skin of unsaturated fatty acids.

[0033] It should be noted that when numerical ranges are mentioned in the claims of this invention, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. To avoid redundancy, the present invention describes preferred embodiments.

[0034] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0035] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A composition for skin cleansing, characterized in that, It contains glycolipids and lauryl ether carboxylic acid surfactants, wherein the mass ratio of the glycolipids to the lauryl ether carboxylic acid surfactants is 3:1 to 1:

3.

2. The composition according to claim 1, characterized in that, The glycolipid is sophorolipid.

3. The composition according to claim 1, characterized in that, The lauryl polyether carboxylic acid surfactant is lauryl polyether-5 carboxylic acid.

4. The composition according to claim 1, characterized in that, The composition also contains anionic surfactants.

5. The composition according to claim 4, characterized in that, The anionic surfactant is selected from one or more of sodium lauryl ether sulfate, sodium lauryl sulfate, and sodium cocoyl methyl taurate.

6. The composition according to claim 1, characterized in that, The composition also contains an amphoteric surfactant.

7. The composition according to claim 6, characterized in that, The zwitterionic surfactant is selected from one or more of cocamidopropyl betaine, sodium lauroyl amphoteric acetate, and disodium cocamidopropyl diacetate.

8. Use of the composition according to any one of claims 1-7 in the preparation of a wash-off personal care product for cleansing skin of unsaturated fatty acids, characterized in that, The unsaturated fatty acid is oleic acid and / or squalene.

9. Use of the composition according to any one of claims 1-7 in the preparation of a wash-off personal care product with reduced skin irritation, characterized in that, The care products are in the form of facial cleanser, shampoo, shower gel, or hand sanitizer.

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