A stable sunscreen lotion that can be phase - converted into a film without emulsifier and its preparation method

Abstract

The present invention relates to the technical field of sunscreen lotions, and specifically to a stable sunscreen lotion that does not contain emulsifiers and can be converted into a film and its preparation method. It includes an oil phase and an aqueous phase. By mass percentage, the oil phase at least includes: silicone oil 0.1-5%, nano-powder dispersion slurry 1-25%, emollient 0.1-5%, oil-soluble sunscreen agent 10-40%; the aqueous phase at least includes: silica 0.5-9%, sodium hyaluronate 0.03-0.4%, deionized water to make up the balance. The average particle size D50 of the silica is ≤7 μm. Under the condition of not additionally adding emulsifiers and film-forming agents, the product can be applied and converted into a film and form a film independently to ensure the effects of waterproofing, sweat resistance, freshness and non-greasiness, and has extremely high market application and promotion value.

Description

Technical Field

[0001] The present invention relates to the technical field of sunscreen lotions, and specifically to a stable sunscreen lotion capable of phase inversion and film formation without emulsifiers and a preparation method thereof. Background Art

[0002] Commercially available sunscreen lotions usually include emulsifiers, which are divided into water-in-oil formula systems and oil-in-water formula systems. Based on the specific usage requirements of sunscreen lotions, water-in-oil sunscreen lotions have insufficient retention of the formula, cannot provide sun protection and sweat resistance, and have insufficient sunscreen performance in human efficacy tests, which limits their production and sales. The prior art adds a high-molecular film-forming agent to the water-in-oil formula system to increase its retention ability. For example, Chinese Patent (Authorized Publication No. CN109833214B) discloses a mild water-in-oil Pickering sunscreen skin care product, which improves the waterproof and sweat-resistant effects by adding sodium polyacryloyldimethyltaurate, but still cannot meet the actual usage requirements. Therefore, the oil-in-water formula has gradually become the mainstream system of sunscreen lotions on the market.

[0003] For oil-in-water sunscreen lotions, the oil is the continuous phase, forming a natural waterproof barrier. When the product is used, it is not easy to get out of makeup, effectively ensuring the continuous output of the sunscreen ability of the product. However, the emulsifiers used in the oil-in-water formula polymerize polydimethylsiloxane functional groups in the molecular chain, which are a type of stable oil-in-water polymerized multi-functional emulsifiers, and their molecular weights are often relatively large, generally above 5000 - 10000 daltons. The addition of large-molecular emulsifiers increases the skin feel stickiness of the formula and reduces the freshness, resulting in discomfort during use. At the same time, calculated by mass percentage, for oil-in-water sunscreen lotions, the continuous phase (oil phase) is generally 30 - 40%, and the dispersed phase (water phase) is 60 - 70%. In order to stabilize the dispersed phase and make the emulsion droplets tightly stable, a high-strength emulsifying interfacial film needs to be formed, which also makes the interfacial tension of the emulsion very large, and then leads to a large application resistance when the emulsion is used, making the already greasy skin feel even more sticky and uncomfortable. In addition, for the oil-in-water sunscreen lotion formula containing surfactants, after encountering water or sweat, the oil film will undergo molecular migration, and the firmness of the oil film is insufficient, making it difficult to ensure long-term non-smudging. For example, Chinese Patent (Authorized Publication No. CN111150677B) discloses a sunscreen cosmetic and a preparation method thereof, which improves the skin feel of the product by introducing polyquaternium-37, but cannot ensure the long-lasting makeup effect. Adding hydrophobic film-forming components will bring a higher molecular weight and a more sticky and obstructive skin feel experience. There are also some products that sacrifice stability to add 0.5 - 1% of emulsifiers to achieve the purpose of improving the skin feel, but they need to be shaken well during use, and the packaging is limited, the manufacturing cost is high, and the operability is insufficient, which limits their application. Summary of the Invention

[0004] To solve the above problems, the present invention provides a stable sunscreen emulsion that can be phase-transformed into a film without emulsifiers. Without the additional addition of emulsifiers and film-forming agents, the product can be applied for phase transformation and self-form a film to ensure the effects of waterproofing, sweat resistance, freshness, and non-greasiness, and has extremely high market application and promotion value.

[0005] On the one hand, the present invention provides a stable sunscreen emulsion that can be phase-transformed into a film without emulsifiers, including an oil phase and a water phase. By mass percentage, the oil phase at least includes: silicone oil 0.1 - 5%, nano-powder dispersion slurry 1 - 25%, emollient 0.1 - 5%, oil-soluble sunscreen agent 10 - 40%; the water phase at least includes: silica 0.5 - 9%, sodium hyaluronate 0.03 - 0.4%, and deionized water to make up the balance.

[0006] As a preferred technical solution, based on the mass of the sunscreen emulsion, the addition amount of the nano-powder dispersion slurry is 2 - 10%.

[0007] As a preferred technical solution, the nano-powder dispersion slurry at least includes nano-powders and a dispersion carrier. The nano-powders are selected from at least one of nano-titanium dioxide, nano-zirconium oxide, and nano-zinc oxide, preferably nano-titanium dioxide.

[0008] Preferably, the mass ratio of the nano-powders is 20 - 50%, preferably 40%.

[0009] Preferably, the nano-powder dispersion slurry is 40wt% nano-Ti 2 dispersion slurry (TINOPLY E50C)

[0010] As a preferred technical solution, the emollient at least includes isononyl isononanoate.

[0011] As a preferred technical solution, the silicone oil at least includes cyclopentasiloxane and polydimethylsiloxane.

[0012] Preferably, the polydimethylsiloxane is selected from at least one of polydimethylsiloxanes with a viscosity of 1 - 350 cSt at 25°C.

[0013] As an example, the polydimethylsiloxane is selected from at least one of polydimethylsiloxanes with a viscosity of 1 cSt, 1.5 cSt, 2 cSt, 2.5 cSt, 3 cSt, 10 cSt, 20 cSt, 50 cSt, 100 cSt, 150 cSt, 200 cSt, 250 cSt, 300 cSt, 350 cSt at 25°C.

[0014] Preferably, the polydimethylsiloxane is a combination of polydimethylsiloxane A with a viscosity of 1-2 cSt at 25°C and polydimethylsiloxane B with a viscosity of 300-350 cSt.

[0015] As a preferred technical solution, the mass ratio of cyclopentadimethylsiloxane, polydimethylsiloxane A, and polydimethylsiloxane B is (1-2):(0.5-2):(0.5-1.5), preferably (1-2):1:(0.5-1).

[0016] As a preferred technical solution, the oil-soluble sunscreen is selected from at least one of ethylhexyl methoxycinnamate, octocrylene, ethylhexyl salicylate, bis-ethylhexyloxyphenol methoxyphenyl triazine, diethylamino hydroxybenzoyl hexyl benzoate, ethylhexyl triazone, and polysiloxane-15.

[0017] Preferably, based on the mass of the sunscreen lotion, the oil-soluble sunscreen includes: 5-10% of ethylhexyl methoxycinnamate, 2-6% of octocrylene, 2-6% of ethylhexyl salicylate, 2-65% of bis-ethylhexyloxyphenol methoxyphenyl triazine, 1-3% of diethylamino hydroxybenzoyl hexyl benzoate, 0.1-1% of ethylhexyl triazone, and 2-5% of polysiloxane-15.

[0018] As a preferred technical solution, based on the mass of the sunscreen lotion, the oil phase further includes 0.1-2% of isododecane and 0.01-0.3% of tocopherol (vitamin E).

[0019] As a preferred technical solution, based on the mass of the sunscreen lotion, the addition amount of silica is 1.5-4.5%.

[0020] As an example, the addition amount of silica is 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%.

[0021] Preferably, the average particle size D50 of the silica is ≤7 μm, preferably 1-7 μm, most preferably 5±2 μm, and the model is Kingsica5020, Linkai powder.

[0022] As a preferred technical solution, based on the mass of the sunscreen lotion, the addition amount of sodium hyaluronate is 0.05-0.3%.

[0023] As an example, the addition amount of sodium hyaluronate is 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.2%, 0.25%, 0.3%.

[0024] As a preferred technical solution, the molecular weight of the sodium hyaluronate is 1.0-1.8 MDa, preferably 1.0-1.5 MDa.

[0025] Preferably, the sodium hyaluronate is moistuHA® sodium hyaluronate.

[0026] As a preferred technical solution, the aqueous phase further includes a preservative, a pH regulator, a conditioner, and a humectant.

[0027] As a preferred technical solution, based on the mass of the sunscreen lotion, the aqueous phase includes: silica 1.5 - 4.5%, sodium hyaluronate 0.05 - 0.3%, p-hydroxyacetophenone 0.01 - 0.4%, 1,2 - hexanediol 0.1 - 0.5%, niacinamide 0.01 - 0.2%, citric acid 0.001 - 0.03%, sodium citrate 0.01 - 0.2%, 1,3 - butanediol 0.1 - 5%, glycerol 0.1 - 8%, allantoin 0.01 - 0.5%, and deionized water to make up the balance.

[0028] In the present invention, by simultaneously adding a nano - powder dispersion slurry, silica, and sodium hyaluronate, when the provided sunscreen lotion has not contacted the skin, the lotion is in an oil - in - water state. When gently applied on the skin surface, the lotion automatically changes its phase and becomes an water - in - oil state. This not only ensures a refreshing and non - sticky use experience but also has a relatively stable water - in - oil state with an autonomous film formation on the surface, ensuring the makeup - holding effect. The possible reason for the analysis is as follows: A stable adsorption angle is formed among the nano - colloid particles, the aqueous phase, and the oil phase in the sunscreen lotion. When the adsorption angle is less than 90°, the lotion is in an oil - in - water state, and when the adsorption angle is greater than 90°, the lotion is in an water - in - oil state. Therefore, it is possible to achieve the change of the two states before and after application, and thus simultaneously ensure the use feel of the lotion and the makeup - holding effect.

[0029] However, the stability of the lotion could not be guaranteed during the early stage of product development. The lotion obtained by directly introducing nano - powder showed an oil - water separation state. Based on a large number of exploratory experiments, it was found that the selection, combination, and addition amount control of the nano - powder dispersion slurry, silica, and sodium hyaluronate directly affect the stability of the lotion. In the present invention, by using a nano - titanium dioxide dispersion slurry in combination with silica with an average particle size D50 ≤ 7μm and moistuHA® sodium hyaluronate, and controlling the addition amount of silica to be 0.5 - 9%, the prepared sunscreen lotion has qualified color, appearance state, viscosity range, and centrifugal, cold - resistance, and heat - resistance stabilities, ensuring the subsequent use effect and sunscreen effect.

[0030] Furthermore, for the sunscreen lotion provided by the present invention, by preferably using a combination of oil - soluble sunscreen agents such as ethylhexyl methoxycinnamate, octocrylene, ethylhexyl salicylate, bis - ethylhexyloxyphenol methoxyphenyl triazine, diethylamino hydroxybenzoyl hexyl benzoate, ethylhexyl triazone, and polysiloxane - 15, the sunscreen effect of the sunscreen lotion is ensured.

[0031] The sunscreen lotion provided by the present invention can achieve the water and sweat resistance ability and effect that only the water-in-oil formulations with film-forming agents added in the market have without additionally adding film-forming agents, achieving a new breakthrough in the technical field of sunscreen lotion formulations.

[0032] On the other hand, the present invention provides a method for preparing a stable sunscreen lotion that can be phase-transformed into a film without an emulsifier, which at least includes the following steps: adding oil-phase raw materials to an oil-phase pot, heating to 85°C - 90°C, and stirring until dissolved to obtain an oil phase; adding water-phase raw materials to an emulsifying pot, heating to 80°C - 85°C, and homogenizing and stirring to obtain a water phase; adding the water phase to the oil phase, with a homogenizing speed of 2000 - 4000 rpm, homogenizing and emulsifying for 3 - 8 minutes, and maintaining the temperature at 80 - 82°C; after emulsification, defoaming under vacuum, cooling and removing the vacuum, continuing to cool, and discharging after passing the sampling inspection to obtain the product.

[0033] The sunscreen lotion provided by the present invention has easily obtainable raw materials, a simple preparation method, is easy to control, and is easy to achieve large-scale industrial production.

[0034] Beneficial effects

[0035] 1. The present invention provides a stable sunscreen lotion that can be phase-transformed into a film without an emulsifier. Without additionally adding an emulsifier and a film-forming agent, the product can be applied and phase-transformed and form a film autonomously to ensure the water and sweat resistance and a fresh and non-greasy effect, having extremely high market application and promotion value.

[0036] 2. By simultaneously adding a nano-powder dispersion slurry, silica, and sodium hyaluronate, when the sunscreen lotion provided by the present invention does not contact the skin, the lotion is in a water-in-oil state. When gently applied on the skin surface, the lotion automatically phase-transforms into an oil-in-water state, which not only ensures a fresh and non-sticky use experience but also has a relatively stable oil-in-water state and forms a film autonomously on the surface to ensure the makeup-holding effect.

[0037] 3. By simultaneously adding a nano-powder dispersion slurry, silica, and sodium hyaluronate, when the sunscreen lotion provided by the present invention does not contact the skin, the lotion is in a water-in-oil state. When gently applied on the skin surface, the lotion automatically phase-transforms into an oil-in-water state, which not only ensures a fresh and non-sticky use experience but also has a relatively stable oil-in-water state and forms a film autonomously on the surface to ensure the makeup-holding effect.

[0038] 4. By preferably using a combination of oil-soluble sunscreen agents such as ethylhexyl methoxycinnamate, octocrylene, ethylhexyl salicylate, bis-ethylhexyloxyphenol methoxyphenyl triazine, diethylamino hydroxybenzoyl hexyl benzoate, ethylhexyl triazone, and polysiloxane-15 in the sunscreen lotion provided by the present invention, the sunscreen effect of the sunscreen lotion is ensured.

[0039] 5. The sunscreen lotion provided by the present invention achieves the water and sweat resistance ability and effect that are only possessed by the water-in-oil formula with a film-forming agent added in the market without adding a film-forming agent additionally, achieving a new breakthrough in the technical field of sunscreen lotion formulations. Description of the Drawings

[0040] Figure 1 It is the product appearance diagram provided by Example 1 of the present invention.

[0041] Figure 2 It is the product appearance diagram provided by Comparative Example 1 of the present invention.

[0042] Figure 3 It is the waterproof effect diagram of the product provided by Example 1 of the present invention.

[0043] Figure 4 It is the waterproof effect diagram of the product provided by Example 2 of the present invention.

[0044] Figure 5 It is the film-forming effect diagram of the product provided by Example 3 of the present invention. Detailed Embodiments

[0045] The grades of each raw material in the examples and comparative examples of the present invention are shown in Table 1.

[0046] Table 1

[0047]

[0048] Examples 1 - 3

[0049] Examples 1 - 3 of the present invention provide a stable sunscreen lotion that can be phase-transformed into a film without an emulsifier. By mass percentage, the preparation raw materials are shown in Table 2.

[0050] Table 2

[0051]

[0052] On the other hand, Examples 1 - 3 of the present invention provide a preparation method of a stable sunscreen lotion that can be phase-transformed into a film without an emulsifier, including the following steps: adding the oil-phase raw materials to an oil-phase pot, heating to 87°C, and stirring until dissolved to obtain an oil phase; adding the water-phase raw materials to an emulsifying pot, heating to 84°C, and homogenizing and stirring to obtain a water phase; adding the water phase to the oil phase, with a homogenizing speed of 2800 rpm, homogenizing and emulsifying for 5 min, and keeping warm at 82°C; after emulsification is completed, defoaming under vacuum (-0.2 Pa), cooling to 42°C and removing the vacuum, continuing to cool to 38°C, and discharging after passing the sampling inspection.

[0053] Comparative Examples 1 - 6

[0054] Comparative Examples 1-6 of the present invention provide a sunscreen lotion. By mass percentage, the raw materials for its preparation are shown in Table 3.

[0055] Table 3

[0056]

[0057] On the other hand, Comparative Examples 1-6 of the present invention provide a method for preparing a sunscreen lotion, including the following steps: adding oil-phase raw materials to an oil-phase pot, heating to 87°C, and stirring until dissolved to obtain an oil phase; adding water-phase raw materials to an emulsifying pot, heating to 84°C, and homogenizing and stirring to obtain a water phase; adding the water phase to the oil phase, with a homogenization speed of 2800 rpm, homogenizing and emulsifying for 5 min, and maintaining the temperature at 82°C; after emulsification is completed, defoaming under vacuum (-0.2 Pa), cooling to 42°C and removing the vacuum, continuing to cool to 38°C, and discharging after sampling and passing the inspection.

[0058] Performance Test

[0059] 1. Use the BASF sunscreen value calculator to calculate the sunscreen values of the sunscreen lotions provided in Examples 1-3 and Comparative Examples 1-6. The test results are shown in Table 4.

[0060] Table 4

[0061]

[0062] 2. Conduct physical and chemical tests on the sunscreen lotions provided in Examples 1-3 and Comparative Examples 1-6. The test reference standards, test items, and test results are shown in Tables 5-13 respectively. The product appearance is shown in Figure 1 、 2 。

[0063] Table 5 Physical and Chemical Test Results of Example 1

[0064]

[0065] Table 6 Physical and Chemical Test Results of Example 2

[0066]

[0067] Table 7 Physical and Chemical Test Results of Example 3

[0068]

[0069] Table 8 Physical and Chemical Test Results of Comparative Example 1

[0070]

[0071] Table 9 Physical and Chemical Test Results of Comparative Example 2

[0072]

[0073] Table 10 Physicochemical Test Results of Comparative Example 3

[0074]

[0075] Table 11 Physicochemical Test Results of Comparative Example 4

[0076]

[0077] Table 12 Physicochemical Test Results of Comparative Example 5

[0078]

[0079] Table 13 Physicochemical Test Results of Comparative Example 6

[0080]

[0081] Analysis of the above table shows that: Compared with the sunscreen lotions provided by Comparative Examples 1-6, the products of Examples 1-3 have qualified product stability, thus ensuring the subsequent sunscreen effect. The sunscreen lotion provided by the present invention needs to add nano-powder dispersion slurry, silica and sodium hyaluronate simultaneously and control their addition amounts to ensure product stability.

[0082] 3. Waterproof effect: The waterproof effect of the products provided in Example 1 and Example 2 was tested (apply the same amount of the products of Example 1 and Example 2, and after 2 minutes, rinse with running water for 10 minutes, check the residual situation of the material body, and judge the waterproof effect). The test results are shown in Figure 3 、 Figure 4 , observe Figure 3 、 4 It can be seen that there is no obvious change before and after flushing, indicating that the products provided in Example 1 and Example 2 have good waterproof effects.

[0083] 4. Film-forming effect: The film-forming effect of the product provided in Example 3 was tested. The product provided in Example 3 was applied on the skin surface, and the application amount was 1 g / 4 cm 2 , and after 2 minutes, a small ball was used to test the film-forming effect. The test results are shown in Figure 5 , observe Figure 5 It can be seen that the small ball adheres to the skin surface, indicating that a film is formed on the skin surface in 2 minutes.

Claims

1. A stable sunscreen emulsion that does not contain an emulsifier and can form a phase transition film, characterized in that: It includes an oil phase and an aqueous phase. Calculated by mass percentage, the oil phase at least includes: 0.1-5% silicone oil, 1-25% nano powder dispersion slurry, 0.1-5% emollient, and 10-40% oil-soluble sunscreen; the aqueous phase at least includes: 1.5-4.5% silica, 0.03-0.4% sodium hyaluronate, and deionized water to make up the balance, and the average particle size of the silica D50 is ≤7μm; the sodium hyaluronate is moistuHA ® sodium hyaluronate; the nano powder dispersion slurry is 40wt% nano TiO2 dispersion slurry.

2. The stable sunscreen emulsion without emulsifier and capable of phase inversion and film formation according to claim 1, characterized in that: The amount of the nano powder dispersion slurry added is 2-10% based on the mass of the sunscreen lotion.

3. The stable sunscreen emulsion capable of phase inversion and film formation without emulsifier according to claim 1, characterized in that: The emollient includes at least isononyl isononanoate.

4. The stable sunscreen emulsion capable of phase inversion and film formation without emulsifier according to claim 1, characterized in that: The silicone oil at least includes cyclopentasiloxane and polydimethylsiloxane.

5. The stable sunscreen emulsion without emulsifier and capable of phase inversion and film formation according to claim 1, characterized in that: The oil-soluble sunscreen is selected from at least one of ethylhexyl methoxycinnamate, octocrylene, ethylhexyl salicylate, bis-ethylhexyloxyphenol methoxyphenyl triazine, diethylaminohydroxybenzoyl hexyl benzoate, ethylhexyl triazone, and polysilicone-15.

6. The stable sunscreen emulsion capable of phase inversion and film formation without emulsifier according to claim 1, characterized in that: Based on the mass of the sunscreen lotion, the oil phase further comprises 0.1-2% isododecane and 0.01-0.3% tocopherol.

7. The stable sunscreen emulsion capable of phase inversion and film formation without emulsifier according to claim 1, characterized in that: The added amount of the silica is 1.5-4.5% based on the mass of the sunscreen lotion.

8. The stable sunscreen emulsion capable of phase inversion and film formation without emulsifier according to claim 1, characterized in that: Based on the mass of the sunscreen lotion, the added amount of the sodium hyaluronate is 0.05-0.3%.

9. A method for preparing a stable sunscreen emulsion that does not contain an emulsifier and can form a phase-inverting film according to any one of claims 1 to 8, characterized in that: The method comprises at least the following steps: adding the oil phase raw material into the oil phase pot, heating it to 85°C-90°C, stirring it until it is dissolved to obtain the oil phase; adding the water phase raw material into the emulsifying pot, heating it to 80°C-85°C, stirring it homogenously to obtain the water phase; adding the water phase into the oil phase, with the homogenizing speed of 2000-4000rpm, homogenizing and emulsifying for 3-8min, and keeping the temperature at 80-82°C; after the emulsification is completed, vacuum defoaming, cooling and venting the vacuum, continuing cooling, sampling and testing to obtain the material after it is qualified.

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