Application of rhamnolipid in sunscreen product and sunscreen product containing rhamnolipid

Abstract

The invention discloses a novel application of rhamnolipid in sunscreen products, which can significantly improve the SPF value and PA value of inorganic sunscreen powder (such as nano titanium dioxide and nano zinc oxide) and enhance the light stability of a sunscreen agent. The content of double rhamnolipid in the used rhamnolipid is greater than 80%, and the range of the carbon chain of fatty acid is C8-C20, preferably C12-C14. The invention also provides a sunscreen product containing the inorganic sunscreen powder and rhamnolipid, and the preparation process of the sunscreen product comprises the following steps: mixing and dissolving the emulsifier, the humectant and the thickener, and then mixing and homogenizing with the rhamnolipid solution and the inorganic sunscreen powder. The sunscreen effect is improved, the addition amount of the inorganic sunscreen powder is reduced, the product cost and negative effects are reduced, and the stability of the formula is enhanced.

Description

Technical Field

[0001] The invention belongs to the field of personal care products, and particularly relates to the application of rhamnolipid in improving the SPF value and PA value of inorganic sunscreen powder. Background Art

[0002] Rhamnolipid is a glycolipid anionic biosurfactant produced by Pseudomonas or Burkholderia. It is composed of rhamnose bound to β-hydroxy fatty acids through 1,4 glycosidic bonds and exists naturally in soil, water and plants. Rhamnolipid is environmentally friendly and completely biodegradable, and is a green surfactant. Rhamnolipid also has a variety of physiological activities, such as antioxidant, anti-inflammatory and anti-tumor effects, and is widely used in oil extraction, agriculture, food, medicine and personal care.

[0003] There are four main structural types of rhamnolipids, namely monorhamnose monolipid, monorhamnose dislipid, disrhamnose monolipid and disrhamnose dislipid. Different types of rhamnolipids have different properties. Disrhamnose lipids have better surface activity and higher HLB value and have a wider range of applications. There is no report on the use of rhamnolipids in improving SPF and PA values.

[0004] Inorganic sunscreens such as nano titanium dioxide and nano zinc oxide have good absorption in both UVA and UVB bands and are broad-spectrum sunscreens. However, due to their water- and oil-insoluble properties, they are usually surface treated in actual applications to be prepared to be hydrophilic, lipophilic or amphiphilic. However, the addition of surface treatment agents (5-30% addition amount) reduces the purity of the sunscreen. When using such sunscreens, a larger amount needs to be added within the regulatory limit. When a large amount of powdered sunscreen is added, it is easy to cause instability in the formula, such as crystallization resulting in rough products and stratification, and a decrease in SPF and PA values. Summary of the invention

[0005] In order to solve the above problems, the present invention discloses the application of rhamnolipid in sunscreen products and sunscreen products containing rhamnolipid. The present invention uses rhamnolipid and inorganic sunscreen powder for premixing. Rhamnolipid generates repulsion between sunscreen powder particles, so that the sunscreen powder is evenly dispersed in the formula, improves SPF and PA values, reduces the amount of sunscreen powder added, saves costs, and improves the stability of the formula.

[0006] The present invention includes the following technical solutions:

[0007] The invention discloses a new application of rhamnolipid in sunscreen products. The rhamnolipid is used to improve the SPF value and PA value of inorganic sunscreen powder.

[0008] Furthermore, in the above application, the rhamnolipid is a rhamnolipid with a disrhamnolipid content greater than or equal to 80%.

[0009] Furthermore, in the above application, the carbon chain range of the fatty acid of the rhamnolipid is C8-C20, preferably C12-C14.

[0010] Furthermore, in the above application, the inorganic sunscreen powder is one or both of nano titanium dioxide and nano zinc oxide.

[0011] Furthermore, in the above application, the nano titanium dioxide or nano zinc oxide is hydrophilic or amphiphilic, and its particle size D50 is 10-100 nm.

[0012] Furthermore, in the above application, rhamnolipid and inorganic sunscreen powder are premixed in a weight ratio of 0.5-2:1.

[0013] The invention also discloses a sunscreen product, which contains inorganic sunscreen powder and rhamnolipid.

[0014] Furthermore, in the above sunscreen product, the inorganic sunscreen powder is selected from one or both of nano titanium dioxide and nano zinc oxide; and the rhamnolipid is a rhamnolipid with a disrhamnolipid content greater than or equal to 80%.

[0015] Furthermore, in the above sunscreen product, the rhamnolipid is a rhamnolipid with a disrhamnolipid content greater than or equal to 80%, and the carbon chain range of its fatty acid is C8-C20, preferably C12-C14; the nano titanium dioxide or nano zinc oxide is hydrophilic or amphiphilic, and its particle size D50 is 10-100nm.

[0016] Furthermore, in the above sunscreen product, the content of the rhamnolipid is 5-20wt%; the content of the nano titanium dioxide or nano zinc oxide is 4-10wt%.

[0017] The present invention also discloses a method for preparing the sunscreen product, comprising the following steps:

[0018] (1) mixing an emulsifier, a moisturizer and a thickener according to a certain proportion, dissolving them completely at 75-85° C., and adjusting the pH to 6.0-7.5;

[0019] (2) Take an appropriate amount of purified water and mix it with rhamnolipid to prepare a 50% solution, then add inorganic sunscreen powder and disperse it evenly at a high speed of 2000 rpm;

[0020] (3) Add (2) to (1) and stir evenly to obtain an aqueous phase;

[0021] (4) Heat the oil phase to 80°C, add it to the water phase and homogenize for 3-10 minutes.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] Significantly improve sun protection effect: By adding rhamnolipids, the SPF value and UVAPF value of sunscreen products are significantly improved, providing consumers with stronger UV protection.

[0024] Enhanced photostability: Even under prolonged light exposure, sunscreen products with added rhamnolipids can still maintain high SPF and UVAPF values, indicating that their sunscreen effect is more lasting and more photostability.

[0025] Reduce the use of inorganic sunscreen powder: Due to the synergistic effect of rhamnolipids, the amount of inorganic sunscreen powder added can be reduced, thereby reducing costs and reducing the negative impact that sunscreens may have on the human body and the environment.

[0026] Improve formula stability: The addition of rhamnolipids helps improve the stability of the formula, prevent precipitation and stratification caused by agglomeration of inorganic sunscreen powders, and improve the overall quality of the product.

[0027] Expanding the application field of rhamnolipids: The present invention provides a new direction for the application of rhamnolipids in personal care products, expands its application scope, and has important market potential and social value. DETAILED DESCRIPTION

[0028] The technical scheme in the embodiment of the present invention is clearly and completely described below, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, rather than all embodiments. Based on the embodiment in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work premise belong to the scope of protection of the present invention. The reagent or instrument used in the embodiment of the present invention do not indicate the manufacturer, and are all conventional reagent products that can be obtained by commercial purchase.

[0029] Table 1 Main raw materials

[0030]

[0031] Examples 1-8 and Comparative Examples 1-2

[0032] Table 2 Sunscreen formula (wt%)

[0033]

[0034]

[0035] The examples and comparative examples were prepared as shown in Table 2, and the preparation method was as follows:

[0036] (1) mixing an emulsifier, a moisturizer and a thickener according to a certain proportion, dissolving them completely at 75-85° C., and adjusting the pH to 6.0-7.5;

[0037] (2) Take an appropriate amount of purified water and mix it with rhamnolipid to prepare a 50% solution, then add inorganic sunscreen powder and disperse it evenly at a high speed of 2000 rpm;

[0038] (3) Add (2) to (1) and stir evenly to obtain an aqueous phase;

[0039] (4) Heat the oil phase to 80°C, add it to the water phase and homogenize for 3-10 minutes.

[0040] Test Example 1

[0041] Stability test

[0042] High temperature stability (45±1)℃, treatment time is 28 days; low temperature stability -5~-10℃, treatment time is 7 days; high and low temperature alternation, treatment time is 14 days. After the test, return to room temperature to observe whether there are precipitation, stratification, roughness, precipitation and other phenomena. The results are shown in Table 3.

[0043] Table 3 Stability test results of embodiments and comparative examples

[0044] high temperature Low temperature Alternate high and low temperatures Example 1 Stablize Stablize Stablize Example 2 Stablize Stablize Stablize Example 3 Stablize Stablize Stablize Example 4 Stablize Stablize Stablize Example 5 Stablize Stablize Stablize Example 6 Stablize Stablize Stablize Example 7 Stablize Stablize Stablize Example 8 Stablize Stablize Stablize Comparative Example 1 Stablize Rough Rough Comparative Example 2 Stablize Rough Rough

[0045] As can be seen from Table 3, the sunscreen formula with rhamnolipid added is more stable in the low temperature and high and low temperature alternation test. The sunscreen formula without rhamnolipid added appears rough in the low temperature and high and low temperature alternation.

[0046] Test Example 2

[0047] Effect of rhamnolipids on improving SPF and PA values

[0048] According to the test method of the "Technical Specification for Safety of Cosmetics" (2015 edition), the SPF value and UVAPF value of the sunscreen were tested after 0, 2, 4, and 6 hours of exposure to light. The results are shown in Tables 4 and 5.

[0049] Table 4. SPF test results of embodiments and comparative examples

[0050] 0hour 2 hours 4 hours 6 hours Example 1 10.62 10.30 9.04 8.56 Example 2 13.85 12.66 11.76 10.89 Example 3 14.02 13.75 12.22 11.53 Example 4 9.88 9.05 8.23 7.32 Example 5 12.23 11.97 10.55 9.34 Example 6 13.85 13.24 12.45 11.03 Example 7 11.43 10.56 9.87 9.02 Example 8 9.66 9.05 8.44 7.37 Comparative Example 1 7.54 6.09 4.05 2.12 Comparative Example 2 6.26 4.87 3.05 1.46

[0051] It can be seen from Table 4 that at 0 hours (i.e., the initial state), the SPF value of the embodiment (sunscreen formula with rhamnolipid added) is significantly higher than that of the comparative example (sunscreen formula without rhamnolipid added). For example, the SPF value of embodiment 1 is 10.62, while that of comparative example 1 is only 7.54. As the illumination time increases (2 hours, 4 hours, 6 hours), the SPF value of the embodiment decreases, but still remains at a high level, while the SPF value of the comparative example decreases sharply. For example, after 6 hours, the SPF value of embodiment 1 is still 8.56, while that of comparative example 1 has dropped to 2.12.

[0052] Table 5. UVAPF value test results of comparative examples and application examples

[0053]

[0054]

[0055] As can be seen from Table 5, similar to the SPF test results, the UVAPF value of the embodiment is significantly higher than that of the comparative example in the initial state. For example, the UVAPF value of embodiment 1 is 7.85, while that of comparative example 1 is only 3.92. As the illumination time increases, the UVAPF value of the embodiment decreases slightly, while the UVAPF value of the comparative example decreases sharply, even to a level of less than 2 after 4 hours, indicating that the sunscreen effect is very limited.

[0056] Therefore, rhamnolipids can effectively enhance the SPF value and PA value of inorganic powder sunscreens and enhance the photostability of the formula.

[0057] From the above embodiments, it can be concluded that the present invention has the following advantages:

[0058] The invention discloses a new application of rhamnolipid in sunscreen products, which significantly improves the SPF value and PA value of the sunscreen products and provides stronger ultraviolet protection ability; secondly, the addition of rhamnolipid enhances the light stability of the sunscreen agent, making the sunscreen effect more durable; furthermore, due to the synergistic effect of rhamnolipid, the usage of inorganic sunscreen powder is reduced, thereby reducing the product cost and the negative impact that the sunscreen agent may have on the human body and the environment; in addition, rhamnolipid is also helpful to improve the stability of the formula, prevent the product from being rough, stratified and other problems, and the invention provides a new direction for the application of rhamnolipid in sunscreen products and expands its application range in the field of personal care.

[0059] The above embodiments show and describe the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. The application of rhamnolipid in sunscreen products is characterized in that: The rhamnolipid is used to improve the SPF value and PA value of inorganic sunscreen powder.

2. The use according to claim 1, characterized in that: The rhamnolipid is a rhamnolipid with a disrhamnolipid content of greater than or equal to 80%.

3. The use according to claim 1, characterized in that: The carbon chain of the fatty acid of the rhamnolipid ranges from C8 to C20, preferably from C12 to C14.

4. The use according to claim 1, characterized in that: The inorganic sunscreen powder is one or both of nano titanium dioxide and nano zinc oxide.

5. The use according to claim 1, characterized in that: The nano titanium dioxide or nano zinc oxide is hydrophilic or amphiphilic, and its particle size D50 is 10-100nm.

6. A sunscreen product, characterized in that: Contains inorganic sunscreen powder and rhamnolipids.

7. A sunscreen product according to claim 6, characterized in that: The inorganic sunscreen powder is selected from one or both of nano titanium dioxide and nano zinc oxide; the rhamnolipid is a rhamnolipid with a disrhamnolipid content greater than or equal to 80%.

8. A sunscreen product according to claim 7, characterized in that: The rhamnolipid is a rhamnolipid with a disrhamnolipid content greater than or equal to 80%, and the carbon chain range of its fatty acid is C8-C20, preferably C12-C14; the nano titanium dioxide or nano zinc oxide is hydrophilic or amphiphilic, and its particle size D50 is 10-100nm.

9. A sunscreen product according to claim 7, characterized in that: In the sunscreen product, the content of the rhamnolipid is 5-20wt%; the content of the nano titanium dioxide or nano zinc oxide is 4-10wt%.

10. The method for preparing a sunscreen product according to any one of claims 6 to 9, characterized in that: The following steps are involved: (1) mixing an emulsifier, a moisturizer and a thickener according to a certain proportion, dissolving them completely at 75-85° C., and adjusting the pH to 6.0-7.5; (2) Take an appropriate amount of purified water and mix it with rhamnolipid to prepare a 50% solution, then add inorganic sunscreen powder and disperse it evenly at a high speed of 2000 rpm; (3) Add (2) to (1) and stir evenly to obtain an aqueous phase; (4) Heat the oil phase to 80°C, add it to the water phase and homogenize for 3-10 minutes.

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