Macromolecular sunscreen cream capable of realizing emulsion phase inversion by washing and preparation method of macromolecular sunscreen cream

Abstract

The invention relates to the technical field of cosmetics, and discloses a macromolecular sunscreen cream capable of realizing emulsion phase inversion by washing and a preparation method thereof, the sunscreen cream with an innovative dosage form is a water-in-oil emulsion through matching design of an emulsifier, and the emulsion can generate phase inversion into oil-in-water when being washed with clear water, so that the effects of preventing water and sweat on the skin and improving the sunscreen effect are realized. The sunscreen cream and physical and chemical sunscreen agents in the sunscreen cream can be washed off under running water, no additional face cleaning or makeup removing product is needed, and meanwhile, natural sunscreen raw materials with synergistic interaction are added in the formula, so that the sunscreen effect of the sunscreen cream is achieved, and the use of the sunscreen agents is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of cosmetics, and in particular to a macromolecular sunscreen cream that can achieve emulsion phase inversion by washing with water and a preparation method thereof. Background Art

[0002] The skin is the first line of defense for the human body to block ultraviolet rays. In order to protect the skin from sunburn, photoaging and photocarcinogenesis under ultraviolet (UV) exposure, sunscreen cosmetics have received more and more attention. The sunscreens used in current sunscreen cosmetics include physical sunscreens and chemical sunscreens. When physical sunscreens and chemical sunscreens are made into sunscreen creams, different dosage forms have different problems. When physical sunscreens and chemical sunscreens are oil-soluble, the sunscreen of oil-in-water sunscreen cream is in the outer phase of the emulsion, and it is necessary to use additional makeup removal products or surfactants to wash it off, otherwise it will remain on the skin. Oil-in-water sunscreen cream wraps the sunscreen in the inner phase of the emulsion, which can achieve water washing of the sunscreen, but it is not waterproof and sweat-proof. The residues of physical sunscreens or chemical sunscreens on the skin can easily cause pores to be clogged, and the lack of waterproof and sweat-proof will result in poor sunscreen effect. Therefore, it is very necessary to achieve a sunscreen that is waterproof, sweat-proof and easy to wash in terms of dosage form. Sunscreen that can achieve phase inversion of the emulsion by washing with water can achieve this effect. However, how to achieve the phase inversion of the emulsion and complete this technological breakthrough is a problem that needs to be solved at present.

[0003] In addition, some chemical sunscreens have the disadvantages of causing skin allergies and phototoxicity, and can have adverse effects on the marine environment, such as benzophenone-3. Physical sunscreens such as titanium dioxide and zinc oxide have the problem of whitening and poor skin feel when used in high dosages. In order to reduce the adverse effects of chemical sunscreens and physical sunscreens, adding sunscreen enhancers from natural sources to sunscreen products is an effective method. Publication No. CN 115487103A discloses a group of sunscreen enhancers including hesperidin and Glycyrrhiza inflata root extract, Scutellaria baicalensis root extract, Sophora flavescens root extract, Taraxacum root extract, and Paeonia suffruticosa root extract to enhance the protection of sunscreens to the skin, but these plant extracts have limited absorption of ultraviolet rays and are relatively expensive, making them unsuitable for large-scale industrial production. Summary of the invention

[0004] In order to solve the technical problems raised in the above background technology that the residues of physical sunscreen or chemical sunscreen on the skin easily lead to clogged pores, and the lack of water and sweat resistance leads to poor sunscreen effect, the present invention provides a macromolecular sunscreen cream that can be washed with water to achieve emulsion phase inversion and a preparation method thereof, which can achieve oil-in-water sunscreen, water-proof and sweat-proof on the skin by selecting the type and ratio of emulsifier, but can be converted into an oil-in-water formulation under running water washing, thereby effectively washing away the sunscreen on the skin.

[0005] The specific technical scheme of the present invention is: a macromolecular sunscreen cream that can achieve emulsion phase inversion by water washing and a preparation method thereof, comprising, by weight, 0.1-10% emulsifier, 0.1-3% stabilizer, 0.1-3% natural sunscreen raw materials, 5-25% sunscreen agent, 10-25% oil raw materials and 45-70% aqueous phase raw materials, wherein the emulsifier is steareth-21 and C12-20 alkyl glucoside in a mass ratio of (3-5):(1-1.2), and the stabilizer is coconut oil glucoside and polyglycerol-3 beeswax acid ester in a mass ratio of (0.8-1.2):(0.8-1.2).

[0006] The most influential factor in determining the type of emulsion (oil-in-water or water-in-oil) is the solubility of the emulsifier in water or oil. Emulsifiers are amphiphilic molecules with hydrophilic groups and lipophilic groups. The hydrophilic-lipophilic balance (HLB value) can be used to represent the hydrophilic or lipophilic ability of the emulsifier. Generally, a system with an HLB value of 1 to 7 can form an oil-in-water emulsion, and a system with an HLB value of 7 to 18 can form an oil-in-water emulsion. The present invention team has concluded through a large number of experiments that the HLB value of the system of this scheme is between the oil-in-water emulsion and the oil-in-water emulsion. The oil-in-water emulsion is transformed into an oil-in-water emulsion when it is washed with water, that is, when the water phase content increases. The reason is presumed to be that when the HLB value of the system is at the critical value of the oil-in-water emulsion and the oil-in-water emulsion, the oil-in-water emulsion is affected by the increase in the water phase content and is transformed into an oil-in-water emulsion. At the same time, the coconut glucoside and polyglycerol-3 beeswax acid ester in the system can not only stabilize the system to form a uniform emulsion, but also have a certain regulating effect on the HLB value of the product. The addition of natural sunscreen raw materials can achieve the sunscreen synergy of the macromolecular sunscreen cream and reduce the use of sunscreen agents.

[0007] Furthermore, the sunscreen includes one or more of physical sunscreens and chemical sunscreens.

[0008] Furthermore, natural sunscreen ingredients include one or more of camellia oil and tea polyphenols. Camellia oil is often used as a moisturizer in cosmetics, and camellia oil also contains flavonoids, which have the function of absorbing ultraviolet rays; tea polyphenols are the active ingredients in tea leaves, which have the function of absorbing ultraviolet rays and scavenging free radicals. The two together have a synergistic effect in sunscreen and can also provide additional protection for the skin, including improving ultraviolet protection, blue light protection, repairing light damage, and increasing SPF / PA values.

[0009] Furthermore, the physical sunscreen is one or more of non-nanoscale titanium dioxide and zinc oxide; the chemical sunscreen is one or more of ethylhexyl methoxycinnamate, ethylhexyl triazone, bis-ethylhexyloxyphenol methoxyphenyl triazine, and methylene bis-benzotriazolyl tetramethylbutylphenol. The physical sunscreen and chemical sunscreen provided by the present invention are both macromolecular sunscreens, do not have the risk of penetrating the skin, and are more suitable for sunscreen products for infants, children and pregnant women.

[0010] Furthermore, the oil raw materials include C12-15 alcohol benzoate, caprylic / capric triglyceride and coconut oil caprylate / caprate.

[0011] Furthermore, the SPF value of the macromolecular sunscreen cream that achieves emulsion phase inversion upon washing is 10 to 50. A method for preparing a macromolecular sunscreen cream that achieves emulsion phase inversion by water washing, characterized in that it comprises the following steps: 1) Weighing an emulsifier, a fat raw material and a sunscreen according to weight, preliminarily mixing them, heating them, and then mixing them with water to homogenize them; 2) cooling, adding natural sunscreen raw materials according to weight ratio and stirring evenly to obtain a macromolecular sunscreen cream that can be washed and achieve emulsion phase inversion.

[0012] Furthermore, in step 1), the heating temperature is 50-80°C.

[0013] Furthermore, in step 1), the homogenization speed is 1000-8000 rpm.

[0014] Furthermore, in step 2), the cooling temperature is 35-40°C.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1) Design of emulsifier types and ratios. The innovative dosage form of macromolecular sunscreen cream is an oil-in-water emulsion. When the cream is washed with clean water, it will undergo a reverse conversion to water-in-oil, thereby achieving waterproof and sweat-proof properties on the skin. At the same time, the macromolecular sunscreen cream and the physical and chemical sunscreens therein can be washed off under running water without the need for additional cleansing or makeup removal products.

[0016] 2) Adding synergistic natural sunscreen raw materials to achieve the sunscreen synergy of the macromolecular sunscreen cream and reduce the use of sunscreen agents, while also providing additional protection for the skin.

[0017] 3) The additives used in the present invention are all macromolecular sunscreens, which do not have the risk of penetrating the skin and are more suitable for sunscreen products for infants, children and pregnant women. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a microscopic image of water-in-oil in Example 1 before phase inversion.

[0019] Figure 2 This is a water-in-oil microscope image after phase inversion of Example 1. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the embodiments.

[0021] Example 1 A macromolecular sunscreen cream that can be washed off to achieve emulsion phase inversion comprises the following steps: 1) Preparation 3.75g of steareth-21, 1.25g of C12-20 alkyl glucoside, 5g of C12-15 alcohol benzoate, 5g of caprylic / capric triglyceride, 10g of coconut oil alcohol-caprylate / caprate, 15g of titanium dioxide, 1g of coconut oil glucoside and 1g of polyglyceryl-3 beeswax ester were heated and mixed at 65°C, and then homogenized with 55g of water in a homogenizer at a high speed of 6000rpm. After running for 10 minutes, the semi-finished product was cooled. After cooling to 35°C, 1.5g of camellia seed oil and 1.5g of tea polyphenols were added with stirring, and the mixture was stirred evenly to obtain a macromolecular sunscreen cream that can be washed to achieve emulsion phase inversion.

[0022] 2) Performance testing The macromolecular sunscreen cream prepared in step 1) that achieves emulsion phase inversion by washing is subjected to a human skin patch test to detect the safety of the product. The detection method is as follows: The use area does not exceed 50mm 2 , a qualified patch test device with a depth of about 1mm, about 0.020g of the tested macromolecular sunscreen cream is placed in the patch tester by the closed patch test method, and a low-allergenic tape is applied to the back of the subject. The test substance is removed after 24 hours, and the skin reaction is observed 0.5h, 24h, and 48h after removal. The results are recorded according to the skin reaction grading standard in the 2015 edition of the "Technical Specifications for Safety of Cosmetics". Grade 0 is a negative reaction, 1 is a suspicious reaction, The macromolecular sunscreen cream prepared in step 1) was subjected to microscopic testing before and after the phase inversion (washing) of the emulsion droplets. The oil-in-water microscopic image before the phase inversion was as follows: Figure 1 As shown, the water-in-oil microscope image after phase inversion is as follows Figure 2 As shown, at the same time, the stability test of the macromolecular sunscreen cream that achieves emulsion phase inversion by water washing is carried out, and the detection method is as follows: Eight groups of samples, each with 30g, were taken and placed at -10℃, 5℃, 25℃ and 45℃ for 90 days respectively to observe whether the products had abnormal conditions such as oil-water separation, stratification, aggregation, etc. If there were abnormal conditions, they were recorded as unstable, and if there were no abnormal conditions, they were recorded as stable.

[0023] The macromolecular sunscreen cream prepared in step 1) that achieves phase inversion by washing is subjected to human SPF test, and the test method is as follows: Preparation of control substance: SPF value 16.1±2.4, prepared according to the standard formula in the "Technical Specification for Safety of Cosmetics" (2015 edition); Subjects: 8 people in total, 4 males and 4 females, aged 24 to 50 years old, meeting the voluntary inclusion criteria of the subjects; Light source: Daylight simulator xenon arc lamp, all performance indicators meet the requirements of the measurement specifications; Inspection is carried out in accordance with the specific requirements of the "Technical Specification for Safety of Cosmetics" (2015 edition). The back of the subject is taken for irradiation. The minimum erythema dose (MED value) of the subject's skin to ultraviolet radiation is predicted 24 hours before the test, and the ultraviolet radiation dose is adjusted according to the predicted results for the test object. On the day of the test, a normal skin area of ​​no less than 30cm is first selected on the back of the subject, according to (2.00+0.05)mg / cm -1 The test object or reference substance is evenly applied to the above-mentioned area with the dosage of 100 mg / kg. Then the irradiation dose is selected according to the specification requirements, and irradiation is performed in three conditions: ① The test object is not applied to the subject's skin; ② The reference substance is applied; ③ The test object is applied. Observe the experimental results after 24 hours and record the MED values ​​in the three conditions respectively.

[0024] Comparative Example 1 The difference between this comparative example and Example 1 is that in this comparative example, the addition ratio of the two emulsifiers in step 1) is steareth-21:C12-20 alkyl glucoside=1:9, that is, the addition amount of steareth-21 is 0.50g, and the addition amount of C12-20 alkyl glucoside is 4.50g. The rest of the process is the same as that in Example 1, and the specific steps are as follows: 1) Preparation 0.50g of steareth-21, 4.50g of C12-20 alkyl glucoside, 5g of C12-15 alcohol benzoate, 5g of caprylic / capric triglyceride, 10g of coconut oil caprylate / caprate, 15g of titanium dioxide, 1g of coconut oil glucoside and 1g of polyglyceryl-3 beeswax ester were heated and mixed at 65°C, and then homogenized with 55g of water in a homogenizer at a high speed of 6000rpm. After running for 10 minutes, the semi-finished product was cooled to 35°C, and 1.5g of camellia seed oil and 1.5g of tea polyphenols were added with stirring. After stirring evenly, a macromolecular sunscreen cream that can be washed to achieve emulsion phase inversion was obtained.

[0025] 2) Performance testing The macromolecular sunscreen cream prepared in step 1) is subjected to a human skin patch test to detect the safety of the product.

[0026] The macromolecular sunscreen cream prepared in step 1) is subjected to microscope test and stability test before phase inversion (washing) and after washing (phase inversion) to remove the emulsion droplets.

[0027] The macromolecular sunscreen cream prepared in step 1) that achieves phase inversion after washing with water is subjected to human SPF test.

[0028] Comparative Example 2 The difference between this comparative example and Example 1 is that in this comparative example, the addition ratio of the two emulsifiers in step 1) is steareth-21:C12-20 alkyl glucoside=1:1, that is, the addition amount of steareth-21 is 2.50g, and the addition amount of C12-20 alkyl glucoside is 2.50g. The rest of the process is the same as Example 1, and the specific steps are as follows: 1) Preparation: 2.50 g of steareth-21, 2.50 g of C12-20 alkyl glucoside, 5 g of C12-15 alcohol benzoate, 5 g of caprylic / capric triglyceride, 10 g of coconut oil alcohol-caprylate / caprate, 15 g of titanium dioxide, 1 g of coconut oil glucoside and 1 g of polyglycerol-3 beeswax acid ester are heated and mixed uniformly at 65° C., and then homogenized with 55 g of water in a homogenizer at a high speed of 6000 rpm. After running for 10 min, the semi-finished product is cooled, cooled to 35° C., and 1.5 g of camellia seed oil and 1.5 g of tea polyphenols are added with stirring, and after stirring uniformly, a macromolecular sunscreen cream that can achieve emulsion phase inversion by washing is obtained.

[0029] 2) Performance Testing The macromolecular sunscreen cream prepared in step 1) is subjected to a human skin patch test to test the safety of the product.

[0030] The macromolecular sunscreen cream prepared in step 1) is subjected to microscope test, HLB value test and stability test before phase inversion (washing) and after washing (phase inversion) to remove the emulsion droplets.

[0031] The macromolecular sunscreen cream prepared in step 1) that achieves phase inversion after washing with water is subjected to human SPF test.

[0032] Table 1 Effect of emulsifier ratio on the performance of macromolecular sunscreen cream It can be concluded from the data in Table 1 that when the ratio of steareth-21 to C12-20 alkyl glucoside in the emulsifier is too high or too low, the HLB value of the final synthesized macromolecular sunscreen cream will not be able to reach around 7, that is, between water-in-oil and oil-in-water. The HLB value of steareth-21 was measured to be 15.6, and the HLB value of C12-20 alkyl glucoside was measured to be 4.4. The large difference in the HLB of the two will cause a change in the ratio, which will have a greater impact on the HLB value of the system.

[0033] Comparative Example 3 The difference between this comparative example and Example 1 is that in step 1), the stabilizers cocoyl glucoside and polyglycerol-3 beeswax acid ester are not added, and the rest of the process is the same as that of Example 1, and the specific steps are as follows: 1) Preparation: 3.75 g of steareth-21, 1.25 g of C12-20 alkyl glucoside, 5 g of C12-15 alcohol benzoate, 5 g of caprylic / capric triglyceride, 10 g of coconut oil alcohol-caprylate / caprate, and 15 g of titanium dioxide are heated and mixed at 65° C. and uniformly homogenized with 57 g of water in a homogenizer at a high speed of 6000 rpm. After running for 10 min, the semi-finished product is cooled to 35° C., and 1.5 g of camellia seed oil and 1.5 g of tea polyphenols are added with stirring. After uniform stirring, a macromolecular sunscreen cream that can achieve emulsion phase inversion by washing is obtained.

[0034] 2) Performance testing The macromolecular sunscreen cream prepared in step 1) is subjected to a human skin patch test to detect the safety of the product.

[0035] The macromolecular sunscreen cream prepared in step 1) is subjected to microscope test, HLB value test and stability test before phase inversion (washing) and after washing (phase inversion) to remove the emulsion droplets.

[0036] The macromolecular sunscreen cream prepared in step 1) that achieves phase inversion after washing with water is subjected to human SPF test.

[0037] Comparative Example 4 The difference between this comparative example and Example 1 is that in step 1), the amount of the stabilizer coco-glucoside added is 1.8 g and the amount of polyglycerol-3 beeswax acid ester added is 0.2 g, and the rest of the process is the same as Example 1, and the specific steps are as follows: 1) Preparation 3.75g of steareth-21, 1.25g of C12-20 alkyl glucoside, 5g of C12-15 alcohol benzoate, 5g of caprylic / capric triglyceride, 10g of coconut oil caprylate, 15g of titanium dioxide, 1.8g of coconut oil glucoside and 0.2g of polyglyceryl-3 beeswax ester were heated and mixed at 65°C, and then homogenized with 55g of water in a homogenizer at a high speed of 6000rpm. After running for 10 minutes, the semi-finished product was cooled. After cooling to 35°C, 1.5g of camellia seed oil and 1.5g of tea polyphenols were added with stirring, and the mixture was stirred evenly to obtain a macromolecular sunscreen cream that can be washed to achieve emulsion phase inversion.

[0038] 2) Performance testing The macromolecular sunscreen cream prepared in step 1) is subjected to a human skin patch test to detect the safety of the product.

[0039] The macromolecular sunscreen cream prepared in step 1) is subjected to microscope test, HLB value test and stability test before phase inversion (washing) and after washing (phase inversion) to remove the emulsion droplets.

[0040] The macromolecular sunscreen cream prepared in step 1) that achieves phase inversion after washing with water is subjected to human SPF test.

[0041] Comparative Example 5 The difference between this comparative example and Example 1 is that in step 1), the amount of the stabilizer coco-glucoside added is 0.2 g and the amount of polyglycerol-3 beeswax acid ester added is 1.8 g, and the rest of the process is the same as Example 1, and the specific steps are as follows: 1) Preparation 3.75g of steareth-21, 1.25g of C12-20 alkyl glucoside, 5g of C12-15 alcohol benzoate, 5g of caprylic / capric triglyceride, 10g of coconut oil caprylate / caprate, 15g of titanium dioxide, 0.2g of coconut oil glucoside and 1.8g of polyglyceryl-3 beeswax ester were heated and mixed at 65°C, and then homogenized with 55g of water in a homogenizer at a high speed of 6000rpm. After running for 10 minutes, the semi-finished product was cooled. After cooling to 35°C, 1.5g of camellia seed oil and 1.5g of tea polyphenols were added with stirring, and the mixture was stirred evenly to obtain a macromolecular sunscreen cream that can be washed to achieve emulsion phase inversion.

[0042] 2) Performance testing The macromolecular sunscreen cream prepared in step 1) is subjected to a human skin patch test to detect the safety of the product.

[0043] The macromolecular sunscreen cream prepared in step 1) is subjected to microscope test, HLB value test and stability test before phase inversion (washing) and after washing (phase inversion) to remove the emulsion droplets.

[0044] The macromolecular sunscreen cream prepared in step 1) that achieves phase inversion after washing with water is subjected to human SPF test.

[0045] Table 2 Effect of the addition and ratio of stabilizers on the performance of macromolecular sunscreen cream It can be concluded from the data in Table 2 that when no stabilizer is added to the formula of the macromolecular sunscreen cream or the addition ratio of the two stabilizers is too high or too low, the stability of the macromolecular sunscreen cream will decrease. The presumed reasons are: the addition of coconut glucoside can increase the elasticity of the emulsion interface film and improve the low-temperature stability of the emulsion, and the addition of polyglycerol-3 beeswax acid ester can strengthen the emulsion interface film to improve the high-temperature stability of the emulsion.

[0046] Comparative Example 6 The difference between this comparative example and Example 1 is that in step 1), no natural sunscreen raw materials are added, and the rest of the process is the same as that of Example 1. The specific steps are as follows: 1) Preparation 3.75g of steareth-21, 1.25g of C12-20 alkyl glucoside, 5g of C12-15 alcohol benzoate, 5g of caprylic / capric triglyceride, 10g of coconut oil alcohol-caprylate / caprate, 15g of titanium dioxide, 1g of coconut oil glucoside and 1g of polyglyceryl-3 beeswax ester were heated and mixed at 65°C, and then homogenized with 58g of water in a homogenizer at a high speed of 6000rpm. After running for 10 minutes, the semi-finished product was cooled to 35°C, and then stirred evenly to obtain a macromolecular sunscreen cream that can be washed to achieve emulsion phase inversion.

[0047] 2) Performance testing The macromolecular sunscreen cream prepared in step 1) is subjected to a human skin patch test to detect the safety of the product.

[0048] The macromolecular sunscreen cream prepared in step 1) is subjected to microscope test, HLB value test and stability test before phase inversion (washing) and after washing (phase inversion) to remove the emulsion droplets.

[0049] The macromolecular sunscreen cream prepared in step 1) that achieves phase inversion after washing with water is subjected to human SPF test.

[0050] Comparative Example 7 The difference between this comparative example and Example 1 is that in step 1), the amount of camellia oil, a natural sunscreen raw material, added is 3 g, and no tea polyphenols are added. The rest of the process is the same as that of Example 1. The specific steps are as follows: 1) Preparation 3.75g of steareth-21, 1.25g of C12-20 alkyl glucoside, 5g of C12-15 alcohol benzoate, 5g of caprylic / capric triglyceride, 10g of coconut oil alcohol-caprylate / caprate, 15g of titanium dioxide, 1g of coconut oil glucoside and 1g of polyglyceryl-3 beeswax ester were heated and mixed at 65°C, and then homogenized with 55g of water in a homogenizer at a high speed of 6000rpm. After running for 10 minutes, the semi-finished product was cooled to 35°C, and 3g of camellia seed oil was added. After stirring evenly, a macromolecular sunscreen cream that can achieve emulsion phase inversion by washing was obtained.

[0051] 2) Performance testing The macromolecular sunscreen cream prepared in step 1) is subjected to a human skin patch test to detect the safety of the product.

[0052] The macromolecular sunscreen cream prepared in step 1) is subjected to microscope test, HLB value test and stability test before phase inversion (washing) and after washing (phase inversion) to remove the emulsion droplets.

[0053] The macromolecular sunscreen cream prepared in step 1) that achieves phase inversion after washing with water is subjected to human SPF test.

[0054] Comparative Example 8 The difference between this comparative example and Example 1 is that in step 1), no natural sunscreen raw material camellia seed oil is added, and the amount of natural sunscreen raw material tea polyphenol added is 3g. The rest of the process is the same as Example 1, and the specific steps are as follows: 1) Preparation 3.75g of steareth-21, 1.25g of C12-20 alkyl glucoside, 5g of C12-15 alcohol benzoate, 5g of caprylic / capric triglyceride, 10g of coconut oil caprylate / caprate, 15g of titanium dioxide, 1g of coconut oil glucoside and 1g of polyglyceryl-3 beeswax were heated and mixed at 65°C, and then homogenized with 55g of water in a homogenizer at a high speed of 6000rpm. After running for 10min, the semi-finished product was cooled to 35°C, and 3g of tea polyphenols was added. After stirring evenly, a macromolecular sunscreen cream that can achieve emulsion phase inversion by washing was obtained.

[0055] 2) Performance testing The macromolecular sunscreen cream prepared in step 1) is subjected to a human skin patch test to detect the safety of the product.

[0056] The macromolecular sunscreen cream prepared in step 1) is subjected to microscope test, HLB value test and stability test before phase inversion (washing) and after washing (phase inversion) to remove the emulsion droplets.

[0057] The macromolecular sunscreen cream prepared in step 1) that achieves phase inversion after washing with water is subjected to human SPF test.

[0058] Table 3 Synergistic effect of natural sunscreen ingredients From the data in Table 3, it can be concluded that when natural sunscreen ingredients are not added to the formula of the macromolecular sunscreen cream, its SPF value is low. At the same time, when only camellia seed oil or tea polyphenols are added to the formula, the macromolecular sunscreen cream produced is also far lower than when both camellia seed oil and tea polyphenols are added. The reason is presumably that the flavonoid structure in camellia seed oil has the function of absorbing ultraviolet rays; tea polyphenols are the active ingredients in tea leaves, which have the functions of absorbing ultraviolet rays and scavenging free radicals. The combination of the two has a synergistic effect in sunscreen and can also provide additional protection for the skin.

[0059] Example 2 1) Preparation 4g of steareth-21, 1g of C12-20 alkyl glucoside, 5g of C12-15 alcohol benzoate, 5g of caprylic / capric triglyceride, 10g of coconut oil-caprylate / caprate, 5g of titanium dioxide, 5g of ethylhexyl methoxycinnamate, 1g of ethylhexyl triazone, 2g of bis-ethylhexyloxyphenol methoxyphenyl triazine, 2g of methylene bis-benzotriazolyl tetramethylbutylphenol, 0.8g of coconut oil glucoside and 1.2g of polyglycerol-3 beeswax ester are heated and mixed at 65°C, and then homogenized with 57g of water in a homogenizer at a high speed of 6000rpm. After running for 10min, the semi-finished product is cooled. After cooling to 35°C, 0.5g of camellia seed oil and 0.5g of tea polyphenols are added with stirring, and after stirring, a macromolecular sunscreen cream that can achieve emulsion phase inversion by washing is obtained.

[0060] 2) Performance testing The macromolecular sunscreen cream prepared in step 1) is subjected to a human skin patch test to detect the safety of the product.

[0061] The macromolecular sunscreen cream prepared in step 1) is subjected to microscope test, HLB value test and stability test before phase inversion (washing) and after washing (phase inversion) to remove the emulsion droplets.

[0062] The macromolecular sunscreen cream prepared in step 1) that achieves phase inversion after washing with water is subjected to human SPF test.

[0063] Finally, the results of the human skin patch tests of Examples 1 to 2 and Comparative Examples 1 to 8 are as follows: the skin of all test subjects showed negative reactions within 48 hours (the scoring level was all 0), without any irritation, with good mildness and high safety.

[0064] The raw materials and equipment used in the present invention, unless otherwise specified, are all commonly used raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are all conventional methods in the art.

[0065] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A macromolecular sunscreen cream that can be washed off to achieve emulsion phase inversion, characterized in that: The composition comprises the following by weight: 0.1-10% emulsifier, 0.1-3% stabilizer, 0.1-3% natural sunscreen raw material, 5-25% sunscreen, 10-25% oil raw material and 45-70% aqueous phase raw material, wherein the emulsifier is steareth-21 and C12-20 alkyl glucoside in a mass ratio of (3-5):(1-1.2), and the stabilizer is coconut glucoside and polyglyceryl-3 beeswax acid ester in a mass ratio of (0.8-1.2):(0.8-1.2).

2. A macromolecular sunscreen cream for water-washing and emulsion phase inversion according to claim 1, characterized in that: The sunscreen includes one or more physical sunscreens and chemical sunscreens.

3. A macromolecular sunscreen cream that can be washed with water to achieve emulsion phase inversion according to claim 1 or 2, characterized in that: The natural sunscreen ingredients include camellia seed oil and tea polyphenols in a weight ratio of (0.8:1.2):(0.8:1.2).

4. A macromolecular sunscreen cream for water-washing and emulsion phase inversion according to claim 2, characterized in that: The physical sunscreen is one or more of non-nano titanium dioxide and zinc oxide; the chemical sunscreen is one or more of ethylhexyl methoxycinnamate, ethylhexyl triazone, bis-ethylhexyloxyphenol methoxyphenyl triazine, and methylene bis-benzotriazolyl tetramethylbutylphenol.

5. The macromolecular sunscreen cream for water-washing and emulsion phase inversion according to claim 1, characterized in that: The oil raw materials include C12-15 alcohol benzoate, caprylic / capric triglyceride and coconut oil caprylate / caprate.

6. The macromolecular sunscreen cream for water-washing and emulsion phase inversion according to claim 1, characterized in that: The SPF value of macromolecular sunscreen creams that can achieve emulsion phase inversion after washing with water is 10~50.

7. A method for preparing a macromolecular sunscreen cream that can be washed to achieve emulsion phase inversion according to any one of claims 1 to 6, characterized in that: The following steps are involved: 1) Weigh the emulsifier, oil raw material and sunscreen according to weight, preliminarily mix them, heat them, mix them with water and homogenize them; 2) Cooling, adding natural sunscreen raw materials according to weight ratio and stirring evenly to obtain a macromolecular sunscreen cream that can be washed and achieve emulsion phase inversion.

8. The method for preparing a macromolecular sunscreen cream capable of achieving emulsion phase inversion by water washing according to claim 7, characterized in that: In step 1), the heating temperature is 50-80°C.

9. The method for preparing a macromolecular sunscreen cream capable of achieving emulsion phase inversion by water washing according to claim 7 or 8, characterized in that: In step 1), the homogenizing speed is 1000~8000rpm.

10. The method for preparing a macromolecular sunscreen cream capable of achieving phase inversion by washing with water according to claim 7, characterized in that: In step 2), the cooling temperature is 35-40°C.

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