A light sunscreen emulsion and a preparation method thereof

Abstract

This invention discloses a refreshing sunscreen lotion and its preparation method, belonging to the field of cosmetic technology. The preparation method includes: S1: heating and melting triethoxyoctylsilane, stearic acid, and silanized modified dextrin palmitate; adding nano-zinc oxide, nano-titanium dioxide, and an amphiphilic copolymer modifier; stirring while heating; adding silica, polymethylsilsesquioxane, and aluminum hydroxide; and then gradient grinding to obtain a modified sunscreen powder dispersion; S2: dissolving a moisturizer and water; adding an emulsifier and distearate dimethylammonium lithium montmorillonite; and homogenizing to obtain a moisturizing emulsion; S3: heating the oil-phase base raw materials; adding the modified sunscreen powder dispersion; homogenizing; adding an oil-soluble sunscreen agent, antioxidant, whitening ingredient, and moisturizing emulsion; homogenizing; adding ethanol, skin protectant, preservative, skin feel modifier, and film-forming agent; and then homogenizing, defoaming, and filtering to obtain the finished product. The prepared product has sun protection, soothing and anti-inflammatory, and barrier repair effects.

Description

Technical Field

[0001] This invention relates to the field of cosmetic technology, specifically to a refreshing sunscreen lotion and its preparation method. Background Technology

[0002] With the increasing awareness of sun protection in skincare, sunscreen products have become a core component of daily skincare routines. Consumers' demands have evolved from simple UV protection to a more comprehensive approach, seeking high-efficiency sun protection, comfortable feel, and multi-faceted care. UVA and UVB rays directly damage skin cell DNA, leading to sunburn, age spots, wrinkles, and other problems. Therefore, high-efficiency, broad-spectrum sun protection is a core requirement for these products. However, existing sunscreen products still face numerous technical bottlenecks in formula design and process optimization, limiting improvements in product quality.

[0003] Existing sunscreen products generally suffer from poor dispersion stability of sunscreen agents. Physical sunscreen ingredients are prone to particle aggregation, leading to severe whitening and a rough skin feel. Chemical sunscreen ingredients, on the other hand, often make products sticky and heavy due to their oil-soluble properties, easily clogging pores after application and failing to meet consumers' demand for a refreshing and breathable feel. At the same time, balancing stability and moisturizing performance is a technical challenge in the industry. Formulas that prioritize stability often achieve system stability by increasing the amount of emulsifiers or thickeners, but this increases the burden on the skin. On the other hand, products that pursue moisturizing effects are prone to stability problems such as layering and crystallization during low-temperature storage or long-term use, affecting the product's lifespan.

[0004] Furthermore, the limited functionality of traditional sunscreens makes it difficult to meet the diverse needs of today's consumers. Most products focus solely on sun protection, lacking auxiliary skin care benefits. Long-term use can lead to dryness, sensitivity, and other discomfort due to the irritation of sunscreen agents. Simultaneously, the traditional manufacturing process lacks precise control over parameters such as temperature and rotation speed during the fusion of raw materials, resulting in significant performance variations between batches and hindering the achievement of consistent quality in large-scale production. These technological shortcomings collectively restrict the market competitiveness of sunscreen products. Therefore, developing a sunscreen lotion that combines high-efficiency sun protection, a refreshing feel, high stability, and multiple skin care benefits has become an important research direction in the cosmetics industry. Summary of the Invention

[0005] To address the technical problems mentioned in the background section, this invention provides a refreshing sunscreen lotion and its preparation method.

[0006] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a method for preparing a refreshing sunscreen lotion, comprising the following preparation steps: S1: Triethoxyoctylsilane, stearic acid and silanized modified dextrin palmitate are mixed and heated to melt. Nano zinc oxide, nano titanium dioxide and amphiphilic copolymer modifier are added, and the mixture is heated and stirred. Silica, polymethylsilsesquioxane and aluminum hydroxide are then added and subjected to gradient grinding to obtain a modified sunscreen powder dispersion. S2: Add humectant and water to the emulsification pot, heat and stir to dissolve, add emulsifier, distearate, lithium dimethylammonium montmorillonite for the first homogenization treatment, keep warm and stir, then cool down to obtain humectant emulsion. S3: Heat the oil-phase base material, add the modified sunscreen powder dispersion obtained in step S1, and perform a second homogenization treatment to obtain the sunscreen base material; add oil-soluble sunscreen agent, water-based sunscreen agent, and antioxidant to the sunscreen base material, stir evenly, cool down, add whitening ingredients, stir evenly, add the moisturizing emulsion obtained in step S2, and perform a third homogenization treatment; after cooling down, add ethanol, skin protectant, preservative, and skin feel modifier; continue cooling and add film-forming agent, and adjust the pH value of the system with pH adjuster; finally, after a fourth homogenization treatment, vacuum degassing, and filtration, obtain a refreshing sunscreen emulsion.

[0007] Furthermore, the preparation method of the amphiphilic copolymer modifier is as follows: γ-methacryloxypropyltrimethoxysilane, methacrylic acid, methacryloxyethyltrimethylammonium chloride, and azobisisobutyronitrile were added to anhydrous ethanol, placed in a reaction vessel, and heated to 70℃-75℃ under nitrogen protection. The mixture was stirred for 3.5h-4.5h and then cooled to obtain an amphiphilic copolymer modifier.

[0008] Further, the amphiphilic copolymer modifier, by weight, comprises 4.0-6.0 parts of γ-methacryloyloxypropyltrimethoxysilane, 2.5-3.5 parts of methacrylic acid, 2.0-3.0 parts of methacryloyloxyethyltrimethylammonium chloride, 0.1-0.2 parts of azobisisobutyronitrile, and 15.0-20.0 parts of anhydrous ethanol.

[0009] Furthermore, the preparation method of the silanized modified dextrin palmitate is as follows: Dextrin palmitate was added to anhydrous ethanol and stirred to disperse. Then, γ-aminopropyltriethoxysilane and glacial acetic acid were added, and the temperature was raised to 75℃-80℃. The mixture was stirred at a constant temperature for 4-5 hours. After the reaction was completed, rotary evaporation was performed to obtain silanized modified dextrin palmitate.

[0010] Further, the silanized modified dextrin palmitate is composed of 6.0-8.0 parts dextrin palmitate, 18.0-22.0 parts anhydrous ethanol, 0.2-0.3 parts glacial acetic acid, and 1.0-1.5 parts γ-aminopropyltriethoxysilane by weight.

[0011] Further, in step S1, the modified sunscreen powder dispersion, by weight, comprises 7.0-8.5 parts of nano zinc oxide, 2.0-3.0 parts of nano titanium dioxide, 0.3-0.5 parts of triethoxyoctylsilane, 0.2-0.3 parts of stearic acid, 0.6-1.2 parts of amphiphilic copolymer modifier, 0.9-1.6 parts of silanized modified dextrin palmitate, 1.5-2.5 parts of silica, 0.1-0.2 parts of polymethylsilsesquioxane, and 0.2-0.4 parts of aluminum hydroxide.

[0012] Further, in step S2, the moisturizing emulsion, by weight, consists of 10.0-13.0 parts water, 7.02-9.14 parts humectant, 2.5-3.5 parts emulsifier, and 0.2-0.4 parts distearate dimethylammonium lithium montmorillonite.

[0013] Further, the moisturizer is composed of 3.5-4.5 parts butylene glycol, 2.0-2.5 parts glycerin, 0.5-0.7 parts trehalose, 0.5-0.7 parts erythritol, 0.4-0.6 parts panthenol, 0.4-0.6 parts 1,2-hexanediol, and 0.02-0.04 parts sodium hyaluronate; the emulsifier is lauryl PEG-9 polydimethylsiloxane-ethyl polydimethylsiloxane.

[0014] Further, in step S3, the refreshing sunscreen lotion, by weight, comprises 27.0-31.0 parts of oil-phase base raw materials, 11-15 parts of modified sunscreen powder dispersion obtained in step S1, 15.8-19.7 parts of oil-soluble sunscreen agent, 0.8-1.2 parts of water-based sunscreen agent, 0.008-0.009 parts of antioxidant, 2.5-3.51 parts of whitening ingredient, 19.72-26.04 parts of moisturizing emulsifier obtained in step S2, 9-11 parts of ethanol, 0.7-1.1 parts of skin protectant, 0.8-1.2 parts of skin feel modifier, 0.35-0.45 parts of preservative, 0.8-1.2 parts of film-forming agent, 0.7-0.9 parts of sodium chloride, and 0.08-0.12 parts of fragrance.

[0015] Further, the oil-phase base raw material, by weight, consists of 20-22 parts of polydimethylsiloxane, 7-9 parts of isododecane, and 0.08-0.12 parts of propylene glycol carbonate; the oil-soluble sunscreen agent, by weight, consists of 8.0-8.5 parts of ethylhexyl methoxycinnamate, 3.5-4.5 parts of ethylhexyl salicylate, 2.0-3.0 parts of hexyl diethylaminohydroxybenzoylbenzoate, 1.5-2.5 parts of octocrylene, and 0.8-1.2 parts of bis-ethylhexyloxyphenol methoxyphenyl triazine; the antioxidant is butylated hydroxytoluene; and the water-based sunscreen agent is phenylbenzimidazole sulfonic acid.

[0016] Furthermore, the whitening ingredient, by weight, comprises 2.5-3.5 parts of niacinamide, 0.0008-0.0012 parts of 3-o-ethyl ascorbic acid, 0.0008-0.0012 parts of ascorbic acid tetraisopalmitate, 0.0008-0.0012 parts of α-arbutin, 0.0008-0.0012 parts of phenylethyl resorcinol, and 0.0008-0.0012 parts of tranexamic acid.

[0017] Further, the skin protectant, by weight, comprises 0.15-0.25 parts of dipotassium glycyrrhizate, 0.4-0.6 parts of compound plant extract A, and compound plant extract B. The compound plant extract A, by weight, consists of 0.15-0.25 parts of water, 0.19-0.3 parts of glycerin, 0.005-0.007 parts of matricaria flower extract, 0.005-0.007 parts of dandelion rhizome / root extract, 0.005-0.007 parts of violet extract, 0.005-0.007 parts of peony root extract, 0.002-0.003 parts of mallow flower extract, 0.002-0.003 parts of honeysuckle flower extract, and 0.0002-0.0003 parts of aloe vera leaf juice; the compound plant extract B, by weight, consists of 0.002-0.003 parts of saffron flower extract, 0.02-0.03 parts of 1,3-propanediol, and 0.12-0.24 parts of water.

[0018] Further, the skin feel modifier is dextrin palmitate; the preservative is composed of 0.3-0.4 parts of p-hydroxyacetophenone, 0.05-0.06 parts of capryloyl hydroxamic acid, and 0.004-0.005 parts of glyceryl caprylate; and the film-forming agent is trimethylsiloxysilicate.

[0019] Further, in step S1, triethoxyoctylsilane, stearic acid, and silanized modified dextrin palmitate are mixed and heated to 60℃-65℃ to melt them; nano zinc oxide, nano titanium dioxide, and amphiphilic copolymer modifier are added, and the mixture is heated and stirred for 6min-10min at a stirring temperature of 65℃-70℃; gradient grinding is performed using a three-roll mill, and the grinding is performed three times, with the grinding gaps set successively to 45μm-55μm, 25μm-35μm, and 8μm-12μm.

[0020] Further, in step S2, after adding the humectant and water to the emulsification pot, the temperature is raised to 85℃-90℃, and the stirring speed is 750rpm-850rpm; after adding the emulsifier, distearate, dimethylammonium montmorillonite, and other ingredients, a first homogenization treatment is performed at a speed of 2800rpm-3200rpm for 8min-12min; after completion, the mixture is kept at 83℃-87℃ and stirred for 25min-35min; then the temperature is lowered at a rate of 0.8℃ / min-1.2℃ / min until it reaches 63℃-67℃ to obtain the humectant emulsion.

[0021] Further, in step S3, the oil phase base material is heated to 58℃-62℃, and after adding the modified sunscreen powder dispersion obtained in step S1, a second homogenization treatment is performed at a speed of 1900rpm-2100rpm for 4min-6min; after adding the whitening ingredient, it is stirred evenly at a speed of 450rpm-550rpm for 2min-4min; after adding the moisturizing emulsion obtained in step S2, a third homogenization treatment is performed at a speed of 2400rpm-2600rpm for 7min-9min.

[0022] Further, in step S3, the temperature is lowered to 43℃-47℃ at a rate of 0.6℃ / min-1.0℃ / min, ethanol is added, along with a skin protectant, preservative, and skin feel modifier, and the mixture is stirred evenly. The temperature is then lowered further to 36℃-40℃, at which point a film-forming agent is added. Simultaneously, the pH of the system is adjusted to 5.8-6.8 using sodium hydroxide solution. A fourth homogenization process is then performed at a speed of 1700rpm-1900rpm, with a total of three homogenization operations, each lasting 9s-11s. After homogenization, vacuum degassing is performed at a vacuum level of -0.1MPa to -0.08MPa for 13min-17min. Finally, filtration is performed using 200-300 mesh nylon filter cloth, with the filtration temperature controlled at 35℃-40℃.

[0023] On the other hand, the present invention provides a method for preparing a refreshing sunscreen lotion, resulting in a refreshing sunscreen lotion.

[0024] The beneficial effects of this invention are: 1. This invention employs a staged preparation method combined with multi-stage dispersion treatment. In step S1, the nano-sunscreen powder undergoes dual modification and gradient grinding to achieve a uniform and stable dispersion of physical sunscreen particles, effectively avoiding the problem of sunscreen agents easily crystallizing and agglomerating in traditional sunscreen products. Simultaneously, in step S2, precise control of emulsification temperature, homogenization speed, and cooling rate forms a structurally stable moisturizing emulsion system, laying the foundation for subsequent fusion with aqueous and oil-phase raw materials. Step S3, through the staged addition of different functional components and multi-stage homogenization treatment, ensures that active substances such as sunscreen agents, whitening ingredients, and skin protectants are uniformly distributed in the system and maintain their activity, achieving an ideal balance between sun protection performance, skin feel, and stability in the final product.

[0025] 2. The refreshing sunscreen lotion prepared by this invention possesses comprehensive and balanced performance. Testing showed that the product achieved a high SPF value, demonstrating excellent broad-spectrum sun protection capabilities and providing effective UV protection for the skin. In terms of stability, the product maintained a homogeneous state after long-term storage at room temperature and low-temperature freezing tests, with minimal viscosity change and almost no stratification after centrifugation, demonstrating excellent system stability. Regarding skin feel, the product forms a film quickly after application, has a light and non-sticky texture, good breathability, and a long-lasting moisturizing sensation, significantly improving the comfort of using sunscreen products. Furthermore, by incorporating multiple whitening active ingredients and compound plant extracts, the product provides sun protection while also offering multiple nourishing effects such as melanin inhibition, soothing and anti-inflammatory properties, and barrier repair, meeting consumers' upgraded needs for multi-functional sunscreen products.

[0026] 3. This invention achieves controllable product performance and batch-to-batch reproducibility through precise control of process parameters and scientific component compounding design. During the preparation process, key parameters such as temperature, rotation speed, and time are meticulously set at each step to ensure that each batch of product meets high quality standards, providing a reliable guarantee for large-scale production. Simultaneously, the prepared sunscreen emulsion is uniformly dispersed and the system is stable, effectively avoiding the problem of diminished protective effect caused by sunscreen agent aggregation in traditional sunscreen products, ensuring the continuous stability of sun protection performance throughout the product's entire lifespan. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The specific parameters of the raw materials used in this invention are as follows: The polydimethylsiloxane used in this invention was purchased from Shandong Junteng Chemical Co., Ltd.

[0029] The nano zinc oxide product used in this invention has a specification of 100nm and was purchased from Shenzhen Jingcai Chemical Co., Ltd.

[0030] The lauryl PEG-9 polydimethylsiloxane used in this invention was purchased from Yeohan International Co., Ltd., South Korea.

[0031] The nano-titanium dioxide used in this invention has a particle size of 20,000 mesh and was purchased from Qinghe County Xingxin New Material Technology Co., Ltd.

[0032] The polymethylsilsesquioxane used in this invention was purchased from Hubei Langbowan Biomedical Co., Ltd.

[0033] The dextrin palmitate used in this invention has the CAS number 83271-10-7 and was purchased from Wuhan Kemic Biomedical Technology Co., Ltd.

[0034] The chamomile (CHAMOMILLA RECUTITA) flower extract used in this invention was purchased from IDBIO SAS.

[0035] The rhizome / root extract of taraxacum officinale used in this invention was purchased from IDBIOSAS.

[0036] The Viola yedoensis extract used in this invention was purchased from IDBIO SAS.

[0037] The peony (PAEONIA LACTIFLORA) root extract used in this invention was purchased from IDBIO SAS.

[0038] The Malva sylvestris flower extract used in this invention was purchased from IDBIO SAS.

[0039] The honeysuckle (LONICERA JAPONICA) flower extract used in this invention was purchased from IDBIO SAS.

[0040] The Aloe Barbadensis leaf juice used in this invention was purchased from IDBIO SAS.

[0041] The distearate dimethylammonium lithium montmorillonite used in this invention was purchased from Hubei Jusheng Technology Co., Ltd.

[0042] The saffron (CROCUS SATIVUS) flower extract used in this invention was purchased from IDBIO SAS.

[0043] Example 1 A method for preparing a refreshing sunscreen lotion includes the following preparation steps: The preparation method of the amphiphilic copolymer modifier is as follows: By weight, 4.0 parts of γ-methacryloxypropyltrimethoxysilane, 2.5 parts of methacrylic acid, 2.0 parts of methacryloxyethyltrimethylammonium chloride, 0.1 parts of azobisisobutyronitrile, and 15.0 parts of anhydrous ethanol were taken. γ-methacryloxypropyltrimethoxysilane, methacrylic acid, methacryloxyethyltrimethylammonium chloride, and azobisisobutyronitrile were added to anhydrous ethanol, placed in a reaction vessel, heated to 70°C under nitrogen protection, and stirred for 3.5 h. After cooling, an amphiphilic copolymer modifier was obtained.

[0044] The preparation method of silanized modified dextrin palmitate is as follows: By weight, 6.0 parts of dextrin palmitate, 18.0 parts of anhydrous ethanol, 0.2 parts of glacial acetic acid, and 1.0 part of γ-aminopropyltriethoxysilane were taken. The dextrin palmitate was added to anhydrous ethanol and stirred at 65°C and 300 rpm until completely dispersed. γ-aminopropyltriethoxysilane and glacial acetic acid were added, and the temperature was raised to 75°C. The mixture was stirred at a constant temperature for 4 hours. After the reaction was completed, the mixture was rotary evaporated at a vacuum of -0.09 MPa and a temperature of 50°C for 4 hours to obtain silanized modified dextrin palmitate.

[0045] S1: By weight, take 7.0 parts of nano zinc oxide, 2.0 parts of nano titanium dioxide, 0.3 parts of triethoxyoctylsilane, 0.2 parts of stearic acid, 0.6 parts of amphiphilic copolymer modifier, 0.9 parts of silanized modified dextrin palmitate, 1.5 parts of silica, 0.1 parts of polymethylsilsesquioxane, and 0.2 parts of aluminum hydroxide; mix triethoxyoctylsilane, stearic acid, and silanized modified dextrin palmitate, and heat to 60℃ to melt; add nano zinc oxide, nano titanium dioxide, and amphiphilic copolymer modifier, and heat and stir for 6 minutes at a stirring temperature of 65℃; then add silica, polymethylsilsesquioxane, and aluminum hydroxide, and perform gradient grinding 3 times using a three-roll mill, with grinding gaps of 45μm, 25μm, and 8μm respectively, to obtain a modified sunscreen powder dispersion.

[0046] S2: By weight, take 10.0 parts water, 7.02 parts humectant (composed of 3.5 parts butylene glycol, 2.0 parts glycerin, 0.5 parts trehalose, 0.5 parts erythritol, 0.4 parts panthenol, 0.4 parts 1,2-hexanediol, and 0.02 parts sodium hyaluronate), 2.5 parts emulsifier (lauryl PEG-9 polydimethylsiloxane-ethyl polydimethylsiloxane), and 0.2 parts distearate dimethylammonium lithium montmorillonite; add the humectant and water to the emulsification pot, heat to 85℃, and stir at 750 rpm to dissolve; add the emulsifier and distearate dimethylammonium lithium montmorillonite, and perform the first homogenization treatment at 2800 rpm for 8 min; keep warm and stir at 83℃ for 25 min, and then cool to 63℃ at a cooling rate of 0.8℃ / min to obtain the humectant emulsion.

[0047] S3: By weight, take 27.0 parts of oil-phase base raw material (composed of 20 parts of polydimethylsiloxane, 7 parts of isododecane, and 0.08 parts of propylene glycol carbonate), 11 parts of the modified sunscreen powder dispersion obtained in step S1, 15.8 parts of oil-soluble sunscreen agent (composed of 8.0 parts of ethylhexyl methoxycinnamate, 3.5 parts of ethylhexyl salicylate, 2.0 parts of diethylaminohydroxybenzoyl benzoate, 1.5 parts of octocrylene, and 0.8 parts of bis-ethylhexyloxyphenol methoxyphenyl triazine), and water-based sunscreen agent (phenylbenzene). The ingredients include: 0.8 parts of imidazolium sulfonic acid, 0.008 parts of antioxidant (butylated hydroxytoluene), 2.5 parts of whitening ingredient (composed of 2.5 parts of niacinamide, 0.0008 parts of 3-o-ethyl ascorbic acid, 0.0008 parts of ascorbic acid tetraisopalmitate, 0.0008 parts of α-arbutin, 0.0008 parts of phenylethyl resorcinol, and 0.0008 parts of tranexamic acid), 19.72 parts of moisturizing emulsion obtained in step S2, 9 parts of ethanol, and 0.7 parts of skin protectant (composed of 0.15 parts of dipotassium glycyrrhizate, 0.4 parts of compound plant extract A, and compound plant extract B). Composed of 0.15 parts; wherein, compound plant extract A is composed of 0.2 parts water, 0.19 parts glycerin, 0.005 parts matricaria flower extract, 0.005 parts dandelion rhizome / root extract, 0.005 parts violet extract, 0.005 parts peony root extract, 0.002 parts mallow flower extract, 0.002 parts honeysuckle flower extract, and 0.0002 parts aloe vera leaf juice; compound plant extract B is composed of 0.002 parts saffron flower extract, 0.02 parts 1,3-propanediol, and 0.12 parts water), 0.8 parts skin feel modifier (dextrin palmitate), 0.35 parts preservative (composed of 0.3 parts p-hydroxyacetophenone, 0.05 parts capryloyl hydroxamic acid, and 0.004 parts glyceryl caprylate), 0.8 parts film-forming agent (trimethylsiloxane silicate), 0.7 parts sodium chloride, and 0.08 parts fragrance; The oil-phase base material was heated to 58°C, and the modified sunscreen powder dispersion obtained in step S1 was added. A second homogenization treatment was performed at 1900 rpm for 4 minutes to obtain the sunscreen base material. Oil-soluble sunscreen agent, water-based sunscreen agent, and antioxidant butylated hydroxytoluene were added to the sunscreen base material and stirred until homogenized. The mixture was then cooled to room temperature, and whitening ingredients were added. The mixture was stirred at 450 rpm for 2 minutes, and then the moisturizing emulsion obtained in step S2 was added. A third homogenization treatment was performed at 2400 rpm for 7 minutes. Finally, the mixture was homogenized at 0.6°C / min. The temperature was lowered to 43°C, ethanol was added, along with skin protectants, preservatives, skin feel modifiers, and sodium chloride. The temperature was further lowered to 36°C, and film-forming agents and fragrances were added. The pH of the system was adjusted to 5.8 using a 5% sodium hydroxide solution. Then, a fourth homogenization process was performed at 1700 rpm, for a total of 3 homogenizations, each lasting 9 seconds. After that, vacuum degassing was performed at -0.1 MPa for 13 minutes. Finally, the solution was filtered through a 200-mesh nylon filter cloth at a filtration temperature of 35°C to obtain a refreshing sunscreen lotion.

[0048] Example 2 A method for preparing a refreshing sunscreen lotion includes the following preparation steps: The preparation method of the amphiphilic copolymer modifier is as follows: By weight, 5.0 parts of γ-methacryloxypropyltrimethoxysilane, 3.0 parts of methacrylic acid, 2.5 parts of methacryloxyethyltrimethylammonium chloride, 0.15 parts of azobisisobutyronitrile, and 17.5 parts of anhydrous ethanol were taken. γ-methacryloxypropyltrimethoxysilane, methacrylic acid, methacryloxyethyltrimethylammonium chloride, and azobisisobutyronitrile were added to anhydrous ethanol, placed in a reaction vessel, heated to 72°C under nitrogen protection, stirred for 4 hours, and cooled to obtain an amphiphilic copolymer modifier.

[0049] The preparation method of silanized modified dextrin palmitate is as follows: By weight, 7.0 parts of dextrin palmitate, 20.0 parts of anhydrous ethanol, 0.25 parts of glacial acetic acid, and 1.2 parts of γ-aminopropyltriethoxysilane were taken. The dextrin palmitate was added to anhydrous ethanol and stirred at 68°C and 350 rpm until completely dispersed. γ-aminopropyltriethoxysilane and glacial acetic acid were added, and the temperature was raised to 78°C. The mixture was stirred at a constant temperature for 4.5 h. After the reaction was completed, the mixture was rotary evaporated at a vacuum of -0.09 MPa and a temperature of 52°C for 5 h to obtain silanized modified dextrin palmitate.

[0050] S1: By weight, take 7.75 parts of nano zinc oxide, 2.5 parts of nano titanium dioxide, 0.4 parts of triethoxyoctylsilane, 0.25 parts of stearic acid, 0.9 parts of amphiphilic copolymer modifier, 1.2 parts of silanized modified dextrin palmitate, 2.0 parts of silica, 0.15 parts of polymethylsilsesquioxane, and 0.3 parts of aluminum hydroxide; mix triethoxyoctylsilane, stearic acid, and silanized modified dextrin palmitate, and heat to 62.5℃ to melt them; add nano zinc oxide, nano titanium dioxide, and amphiphilic copolymer modifier, and heat and stir for 8 minutes at a stirring temperature of 68℃; then add silica, polymethylsilsesquioxane, and aluminum hydroxide, and perform gradient grinding 3 times using a three-roll mill, with grinding gaps of 50μm, 30μm, and 10μm respectively, to obtain a modified sunscreen powder dispersion.

[0051] S2: By weight, take 11.5 parts water, 8.08 parts humectant (composed of 4.0 parts butylene glycol, 2.25 parts glycerin, 0.6 parts trehalose, 0.6 parts erythritol, 0.5 parts panthenol, 0.5 parts 1,2-hexanediol, and 0.03 parts sodium hyaluronate), 3.0 parts emulsifier (lauryl PEG-9 polydimethylsiloxane-ethyl polydimethylsiloxane), and 0.3 parts distearate dimethylammonium lithium montmorillonite; add the humectant and water to the emulsification pot, heat to 87.5℃, and stir at 800 rpm to dissolve; add the emulsifier and distearate dimethylammonium lithium montmorillonite, and perform the first homogenization treatment at 3000 rpm for 10 min; keep warm and stir at 85℃ for 30 min, and then cool to 65℃ at a cooling rate of 1.0℃ / min to obtain the humectant emulsion.

[0052] S3: By weight, take 29.0 parts of the oil phase base raw material (composed of 21 parts of polydimethylsiloxane, 8 parts of isododecane, and 0.10 parts of propylene glycol carbonate), 13 parts of the modified sunscreen powder dispersion obtained in step S1, 17.75 parts of the oil-soluble sunscreen agent (composed of 8.25 parts of ethylhexyl methoxycinnamate, 4.0 parts of ethylhexyl salicylate, 2.5 parts of diethylaminohydroxybenzoyl benzoate, 2.0 parts of octocrylene, and 1.0 part of bis-ethylhexyloxyphenol methoxyphenyl triazine), antioxidant (butylated hydroxytoluene), and water. The formula includes: 1.0 part of a sunscreen agent (phenylbenzimidazole sulfonic acid), 0.0085 parts of a whitening ingredient (composed of 3.006 parts of niacinamide, 0.0010 parts of 3-o-ethyl ascorbic acid, 0.0010 parts of ascorbic acid tetraisopalmitate, 0.0010 parts of α-arbutin, 0.0010 parts of phenylethyl resorcinol, and 0.0010 parts of tranexamic acid), 22.88 parts of a moisturizing emulsion obtained in step S2, 10 parts of ethanol, and 0.9 parts of a skin protectant (composed of 0.20 parts of dipotassium glycyrrhizate, 0.5 parts of compound plant extract A, and compound plant extract B). Composed of 0.20 parts; wherein, Compound Plant Extract A consists of 0.25 parts water, 0.245 parts glycerin, 0.006 parts matricaria flower extract, 0.006 parts dandelion rhizome / root extract, 0.006 parts violet extract, 0.006 parts peony root extract, 0.0025 parts mallow flower extract, 0.0025 parts honeysuckle flower extract, and 0.00025 parts aloe vera leaf juice; Compound Plant Extract Product B consists of 0.0025 parts of saffron flower extract, 0.025 parts of 1,3-propanediol, and 0.18 parts of water; 1.0 part of skin feel modifier (dextrin palmitate); 0.40 parts of preservative (composed of 0.35 parts of p-hydroxyacetophenone, 0.055 parts of capryloyl hydroxamic acid, and 0.0045 parts of glyceryl caprylate); 1.0 part of film-forming agent (trimethylsiloxysilicate); 0.8 parts of sodium chloride; and 0.10 parts of fragrance. The oil-phase base material was heated to 60°C, and the modified sunscreen powder dispersion obtained in step S1 was added. A second homogenization treatment was performed at 2000 rpm for 5 minutes to obtain the sunscreen base material. Oil-soluble sunscreen agent and antioxidant butylated hydroxytoluene were added to the sunscreen base material and stirred until homogeneous. The mixture was then cooled to room temperature, and whitening ingredients were added. The mixture was stirred at 500 rpm for 3 minutes. The moisturizing emulsion obtained in step S2 was then added, and a third homogenization treatment was performed at 2500 rpm for 8 minutes. The mixture was then cooled at a rate of 0.8°C / min. At 45°C, ethanol was added, along with skin protectants, preservatives, skin feel modifiers, and sodium chloride. The temperature was then lowered to 38°C, and film-forming agents and fragrances were added. The pH of the system was adjusted to 6.3 using a 5% sodium hydroxide solution. A fourth homogenization process was then performed at 1800 rpm, for a total of three homogenizations, each lasting 10 seconds. Vacuum degassing was then performed at -0.09 MPa for 15 minutes. Finally, the solution was filtered through a 250-mesh nylon filter cloth at 37.5°C to obtain a refreshing sunscreen lotion.

[0053] Example 3 A method for preparing a refreshing sunscreen lotion includes the following preparation steps: The preparation method of the amphiphilic copolymer modifier is as follows: By weight, 6.0 parts of γ-methacryloxypropyltrimethoxysilane, 3.5 parts of methacrylic acid, 3.0 parts of methacryloxyethyltrimethylammonium chloride, 0.2 parts of azobisisobutyronitrile, and 20.0 parts of anhydrous ethanol were taken. γ-methacryloxypropyltrimethoxysilane, methacrylic acid, methacryloxyethyltrimethylammonium chloride, and azobisisobutyronitrile were added to anhydrous ethanol, placed in a reaction vessel, heated to 75°C under nitrogen protection, stirred for 4.5 h, and cooled to obtain an amphiphilic copolymer modifier.

[0054] The preparation method of silanized modified dextrin palmitate is as follows: By weight, 8.0 parts of dextrin palmitate, 22.0 parts of anhydrous ethanol, 0.3 parts of glacial acetic acid, and 1.5 parts of γ-aminopropyltriethoxysilane were taken. The dextrin palmitate was added to anhydrous ethanol and stirred at 70°C and 400 rpm until completely dispersed. γ-aminopropyltriethoxysilane and glacial acetic acid were added, and the temperature was raised to 80°C. The mixture was stirred at a constant temperature for 5 hours. After the reaction was completed, the mixture was rotary evaporated under a vacuum of -0.08 MPa and a temperature of 55°C to obtain silanized modified dextrin palmitate.

[0055] S1: By weight, take 8.5 parts of nano zinc oxide, 3.0 parts of nano titanium dioxide, 0.5 parts of triethoxyoctylsilane, 0.3 parts of stearic acid, 1.2 parts of amphiphilic copolymer modifier, 1.6 parts of silanized modified dextrin palmitate, 2.5 parts of silica, 0.2 parts of polymethylsilsesquioxane, and 0.4 parts of aluminum hydroxide; mix triethoxyoctylsilane, stearic acid, and silanized modified dextrin palmitate, and heat to 65°C to melt them; add nano zinc oxide, nano titanium dioxide, and amphiphilic copolymer modifier, and heat and stir for 10 minutes at 70°C; then add silica, polymethylsilsesquioxane, and aluminum hydroxide, and perform gradient grinding three times using a three-roll mill, with grinding gaps of 55μm, 35μm, and 12μm respectively, to obtain a modified sunscreen powder dispersion.

[0056] S2: By weight, take 13.0 parts water, 9.14 parts humectant (composed of 4.5 parts butylene glycol, 2.5 parts glycerin, 0.7 parts trehalose, 0.7 parts erythritol, 0.6 parts panthenol, 0.6 parts 1,2-hexanediol, and 0.04 parts sodium hyaluronate), 3.5 parts emulsifier (lauryl PEG-9 polydimethylsiloxane-ethyl polydimethylsiloxane), and 0.4 parts distearate dimethylammonium lithium montmorillonite; add the humectant and water to the emulsification pot, heat to 90℃, and stir at 850 rpm to dissolve; add the emulsifier and distearate dimethylammonium lithium montmorillonite, and perform the first homogenization treatment at 3200 rpm for 12 min; keep warm and stir at 87℃ for 35 min, and then cool to 67℃ at a cooling rate of 1.2℃ / min to obtain the humectant emulsion.

[0057] S3: By weight, take 31.0 parts of oil-phase base raw material (composed of 22 parts of polydimethylsiloxane, 9 parts of isododecane, and 0.12 parts of propylene glycol carbonate), 15 parts of the modified sunscreen powder dispersion obtained in step S1, 19.7 parts of oil-soluble sunscreen agent (composed of 8.5 parts of ethylhexyl methoxycinnamate, 4.5 parts of ethylhexyl salicylate, 3.0 parts of diethylaminohydroxybenzoyl benzoate, 2.5 parts of octocrylene, and 1.2 parts of bis-ethylhexyloxyphenol methoxyphenyl triazine), and water-based sunscreen agent (phenylbenzoyl... The composition includes: 1.2 parts imidazole sulfonic acid, 0.009 parts antioxidant (butylated hydroxytoluene), 3.51 parts whitening ingredient (composed of 3.5 parts niacinamide, 0.0012 parts 3-o-ethyl ascorbic acid, 0.0012 parts tetraisopalmitate ascorbate, 0.0012 parts α-arbutin, 0.0012 parts phenylethyl resorcinol, and 0.0012 parts tranexamic acid), 26.04 parts moisturizing emulsion obtained in step S2, 11 parts ethanol, and 1.1 parts skin protectant (composed of 0.25 parts dipotassium glycyrrhizate, 0.6 parts compound plant extract A, and compound plant extract B). Composition: 0.25 parts; of which Compound Plant Extract A consists of 0.3 parts water, 0.3 parts glycerin, 0.007 parts matricaria flower extract, 0.007 parts dandelion rhizome / root extract, 0.007 parts violet extract, 0.007 parts peony root extract, 0.003 parts mallow flower extract, 0.003 parts honeysuckle flower extract, and 0.0003 parts aloe vera leaf juice; Compound Plant Extract B consists of 0.003 parts saffron flower extract, 0.03 parts 1,3-propanediol, and 0.24 parts water), 1.2 parts skin feel modifier (dextrin palmitate), 0.45 parts preservative (composed of 0.4 parts p-hydroxyacetophenone, 0.06 parts capryloyl hydroxamic acid, and 0.005 parts glyceryl caprylate), 1.2 parts film-forming agent (trimethylsiloxane silicate), 0.9 parts sodium chloride, and 0.12 parts fragrance; The oil-phase base material was heated to 62°C, and the modified sunscreen powder dispersion obtained in step S1 was added. A second homogenization treatment was performed at 2100 rpm for 6 minutes to obtain the sunscreen base material. Oil-soluble sunscreen agent and antioxidant butylated hydroxytoluene were added to the sunscreen base material and stirred until homogeneous. The mixture was then cooled to room temperature, and whitening ingredients were added. The mixture was stirred at 550 rpm for 4 minutes. The moisturizing emulsion obtained in step S2 was then added, and a third homogenization treatment was performed at 2600 rpm for 9 minutes. The mixture was then cooled at a rate of 1.0°C / min. At 47°C, ethanol is added, along with skin protectant, preservative, skin feel modifier, and sodium chloride. The temperature is then lowered to 40°C, and film-forming agent and fragrance are added. The pH of the system is adjusted to 6.8 using a 5% sodium hydroxide solution. A fourth homogenization process is then performed at 1900 rpm, for a total of three homogenizations, each lasting 11 seconds. Vacuum degassing is then performed at -0.08 MPa for 17 minutes. Finally, the solution is filtered through a 300-mesh nylon filter cloth at 40°C to obtain a refreshing sunscreen lotion.

[0058] Comparative Example 1 Compared with Example 1, this comparative example did not add γ-methacryloyloxypropyltrimethoxysilane during the preparation of the amphiphilic copolymer modifier; the remaining steps and parameters were the same, and will not be repeated in this comparative example. Finally, a refreshing sunscreen lotion was obtained.

[0059] Comparative Example 2 Compared with Example 1, this comparative example did not add methacryloyloxyethyltrimethylammonium chloride during the preparation of the amphiphilic copolymer modifier; the remaining steps and parameters were the same, and will not be repeated in this comparative example. Finally, a refreshing sunscreen lotion was obtained.

[0060] Comparative Example 3 Compared with Example 1, this comparative example replaces "silanized modified dextrin palmitate" with "dextrin palmitate"; the remaining steps and parameters are the same, and will not be repeated in this comparative example. Finally, a refreshing sunscreen lotion is obtained.

[0061] Comparative Example 4 Compared with Example 1, this comparative example did not add distearate dimethylammonium lithium montmorillonite in step S2; the remaining steps and parameters were the same, and will not be repeated here. The final result was a refreshing sunscreen lotion.

[0062] Comparative Example 5 Compared with Example 1, no dextrin palmitate was added in step S3 of this comparative example; the remaining steps and parameters are the same, and will not be repeated in this comparative example. Finally, a refreshing sunscreen lotion was obtained.

[0063] Comparative Example 6 Compared with Example 1, this comparative example did not add trimethylsiloxysilicate in step S3; the remaining steps and parameters were the same, and will not be repeated here. The final result was a refreshing sunscreen lotion.

[0064] Comparative Example 7 Compared with Example 1, in step S3, “compound plant extract A” was replaced with “deionized water”; the remaining steps and parameters are the same, and will not be repeated in this comparative example. Finally, a refreshing sunscreen lotion was obtained.

[0065] Comparative Example 8 Compared with Example 1, in step S3, “compound plant extract B” was replaced with “deionized water”; the remaining steps and parameters are the same, and will not be repeated in this comparative example. Finally, a refreshing sunscreen lotion was obtained.

[0066] The refreshing sunscreen lotions prepared in Examples 1-3 and Comparative Examples 1-8 were tested, and the results are recorded in Tables 1, 2 and 3.

[0067] 1. Sunscreen performance testing: The Sun Protection Factor (SPF) of the refreshing sunscreen lotions prepared in Examples 1-3 and Comparative Examples 1-8 was determined using a UV-2000S UV transmittance tester (Bluefield Company, USA). Following ISO 24443 standards, 32.5 mg of sunscreen lotion was accurately weighed onto a 5 cm × 5 cm PMMA organic plate, quickly and evenly applied using disposable latex gloves, with the residual amount on the plate controlled at 29.0 mg. Each sample was tested three times, and the average of the three measurements was recorded as the final SPF value to evaluate the product's broad-spectrum sun protection capability.

[0068] 2. Stability testing 2.1 Low-temperature stability: The refreshing sunscreen lotions prepared in Examples 1-3 and Comparative Examples 1-8 were sealed and placed in a -10℃ low-temperature environment for 1 month. The samples were observed weekly to check for coagulation or stratification. After being taken out and warmed to room temperature, it was checked whether the homogeneity could be restored, and it was observed whether there were any problems such as sunscreen agent aggregation, precipitation or separation.

[0069] 2.2 Centrifugal stability: Anxin TG16G centrifuge was used. 10 mL of sunscreen emulsion was centrifuged at 3000 rpm for 5 min. The height of the supernatant after centrifugation was measured. The smaller the height, the stronger the anti-stratification ability of the emulsion and the better the stability of the system.

[0070] 3. Skin feel evaluation A panel of 30 professional evaluators was selected to evaluate the skin feel of the refreshing sunscreen lotions prepared in Examples 1-3 and Comparative Examples 1-8 from multiple dimensions. Evaluation indicators included: film-forming speed (time required for the sample to completely dry and become non-sticky after application, scored from 1 to 5, with 5 being the fastest), lightness (the feeling of lightness or heaviness on the skin after application, scored from 1 to 5, with 5 being the lightest), hydration (the feeling of moisture on the skin after application, scored from 1 to 5, with 5 being the most hydrating), and breathability (the feeling of breathability on the skin after application, scored from 1 to 5, with 5 being the most breathable). The average score for each indicator was calculated to comprehensively reflect the skin feel quality of the product.

[0071] 4. Testing of multiple maintenance effects A multi-dimensional instrumental approach was used to comprehensively evaluate the product's diverse skincare effects. Thirty healthy subjects used the product continuously for four weeks under constant temperature and humidity conditions. Tests were conducted before and four weeks after use: The Mexameter MX18 skin melanin analyzer was used to measure changes in facial melanin content, and the melanin reduction rate was calculated to evaluate the whitening effect; the Chromameter CR-400 colorimeter was used to measure changes in the skin erythema index (a value), and the Tewameter TM300 transepidermal water loss analyzer was used to measure transepidermal water loss (TEWL) to comprehensively evaluate the product's anti-inflammatory, soothing, and barrier repair effects. The rate of change for all indicators before and after use was calculated, and statistical analysis was used to determine the product's diverse skincare capabilities.

[0072] Table 1: Results of Sunscreen Performance and Stability Tests Table 2: Skin Feel Evaluation Test Results Table 3: Results of Multi-functional Maintenance Efficacy Tests As shown in Tables 1, 2 and 3, the refreshing sunscreen lotions prepared in Examples 1-3 of this invention exhibit excellent performance in terms of sun protection, stability, skin feel and multiple care effects, which are significantly better than those in Comparative Examples 1-8.

[0073] As shown by the data from Example 1 and Comparative Example 1, in the preparation of the amphiphilic copolymer modifier in Comparative Example 1, γ-methacryloyloxypropyltrimethoxysilane was not added, which destroyed the hydrophobicity and amphiphilic structure of the copolymer, resulting in insufficient coating of the nano sunscreen powder, a significant decrease in dispersion stability, a significant increase in viscosity change during room temperature storage, aggravated stratification after centrifugation, uneven distribution of sunscreen agent leading to a decrease in SPF value, and a significant deterioration in skin feel and multi-care efficacy.

[0074] As shown by the data from Example 1 and Comparative Example 2, in the preparation of the amphiphilic copolymer modifier in Comparative Example 2, methacryloyloxyethyltrimethylammonium chloride was not added, resulting in insufficient hydrophilicity and interfacial compatibility of the copolymer. The powder was unevenly dispersed in the water-oil system, and the system stability, sun protection performance, skin feel and maintenance effect were significantly reduced, and the synergistic and stable dispersion effect could not be achieved.

[0075] The data from Example 1 and Comparative Example 3 show that replacing the silanized dextrin palmitate with unmodified dextrin palmitate in Comparative Example 3 resulted in a significant reduction in dispersion enhancement and silane compatibility, a decrease in the uniformity of sunscreen powder dispersion, and lower system stability, sunscreen effect, skin smoothness, and maintenance performance compared to the Example. This confirms that silanization modification is the key to improving powder dispersion and system compatibility.

[0076] Data from Example 1 and Comparative Example 4 show that: Comparative Example 4 did not add distearate dimethylammonium lithium montmorillonite in step S2, which led to a decrease in the stability of the emulsion system, a significant increase in viscosity changes during room temperature storage, coagulation and stratification at low temperatures, a significant increase in the height of the supernatant after centrifugation, and uneven dispersion of sunscreen agents due to system instability, resulting in a significant weakening of sun protection performance. All indicators of skin feel evaluation decreased simultaneously, and the multi-care efficacy also declined.

[0077] As can be seen from the data shown in Example 1 and Comparative Example 5, Comparative Example 5 did not add dextrin palmitate in step S3. Although the effect on sun protection performance and stability was relatively small, it directly led to a deterioration in skin feel. The film-forming speed, lightness, hydration and breathability scores were significantly reduced, and the stability of the system also decreased to a certain extent.

[0078] The data from Example 1 and Comparative Example 6 show that: Comparative Example 6 did not add trimethylsiloxysilicate in step S3, which severely damaged the film-forming performance of the emulsion, resulting in the lowest film-forming speed score. The sun protection effect was significantly reduced due to the incomplete film layer, the low-temperature stability was worse, the height of the clear liquid after centrifugation was higher, and the overall performance was significantly deteriorated.

[0079] The data from Example 1 and Comparative Example 7 show that replacing compound plant extract A with deionized water in Comparative Example 7 had a relatively small impact on sun protection performance and stability, but the skin's hydration level decreased significantly, and the whitening, anti-inflammatory, and barrier repair capabilities among the multiple skin care effects were all significantly reduced. This indicates that compound plant extract A plays an important role in providing a hydrating skin feel and skin protection effects.

[0080] The data from Example 1 and Comparative Example 8 show that when Comparative Example 8 replaced compound plant extract B with deionized water, the overall multi-care efficacy also decreased. The reduction rate of melanin, the improvement of erythema index, and the reduction of transdermal water loss were all lower than those in Example 1, confirming that compound plant extract B is the key ingredient that gives the product multi-care efficacy.

[0081] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a refreshing sunscreen lotion, characterized in that, The preparation steps include the following: S1: Triethoxyoctylsilane, stearic acid and silanized modified dextrin palmitate are mixed and heated to melt. Nano zinc oxide, nano titanium dioxide and amphiphilic copolymer modifier are added, the mixture is heated and stirred, and then silica, polymethylsilsesquioxane and aluminum hydroxide are added for gradient grinding to obtain modified sunscreen powder dispersion. S2: Add humectant and water to the emulsification pot, heat and stir to dissolve, add emulsifier, distearate, lithium dimethylammonium montmorillonite for the first homogenization treatment, keep warm and stir, then cool down to obtain humectant emulsion. S3: Heat the oil-phase base material, add the modified sunscreen powder dispersion obtained in step S1, and perform a second homogenization treatment to obtain the sunscreen base material; add oil-soluble sunscreen agent, water-based sunscreen agent, and antioxidant to the sunscreen base material, stir evenly, cool down, add whitening ingredients, stir evenly, add the moisturizing emulsion obtained in step S2, and perform a third homogenization treatment; after cooling down, add ethanol, skin protectant, preservative, skin feel modifier, and sodium chloride, and stir evenly; after continuing to cool down, add film-forming agent and fragrance, and adjust the pH value of the system with a pH adjuster; finally, after a fourth homogenization treatment, vacuum degassing, and filtration, obtain a refreshing sunscreen emulsion.

2. The method for preparing a refreshing sunscreen lotion according to claim 1, characterized in that, The preparation method of the amphiphilic copolymer modifier is as follows: γ-methacryloxypropyltrimethoxysilane, methacrylic acid, methacryloxyethyltrimethylammonium chloride, and azobisisobutyronitrile were added to anhydrous ethanol, placed in a reaction vessel, and heated to 70℃-75℃ under nitrogen protection. The mixture was stirred for 3.5h-4.5h and then cooled to obtain an amphiphilic copolymer modifier.

3. The method for preparing a refreshing sunscreen lotion according to claim 2, characterized in that, The amphiphilic copolymer modifier, by weight, consists of 4.0-6.0 parts of γ-methacryloyloxypropyltrimethoxysilane, 2.5-3.5 parts of methacrylic acid, 2.0-3.0 parts of methacryloyloxyethyltrimethylammonium chloride, 0.1-0.2 parts of azobisisobutyronitrile, and 15.0-20.0 parts of anhydrous ethanol.

4. The method for preparing a refreshing sunscreen lotion according to claim 1, characterized in that, The preparation method of the silanized modified dextrin palmitate is as follows: Dextrin palmitate was added to anhydrous ethanol and stirred to disperse. Then, γ-aminopropyltriethoxysilane and glacial acetic acid were added, and the temperature was raised to 75℃-80℃. The mixture was stirred at a constant temperature for 4-5 hours. After the reaction was completed, rotary evaporation was performed to obtain silanized modified dextrin palmitate.

5. The method for preparing a refreshing sunscreen lotion according to claim 4, characterized in that, The silanized modified dextrin palmitate, by weight, is composed of 6.0-8.0 parts dextrin palmitate, 18.0-22.0 parts anhydrous ethanol, 0.2-0.3 parts glacial acetic acid, and 1.0-1.5 parts γ-aminopropyltriethoxysilane.

6. The method for preparing a refreshing sunscreen lotion according to claim 1, characterized in that, In step S1, the modified sunscreen powder dispersion, by weight, consists of 7.0-8.5 parts of nano zinc oxide, 2.0-3.0 parts of nano titanium dioxide, 0.3-0.5 parts of triethoxyoctylsilane, 0.2-0.3 parts of stearic acid, 0.6-1.2 parts of amphiphilic copolymer modifier, 0.9-1.6 parts of silanized modified dextrin palmitate, 1.5-2.5 parts of silica, 0.1-0.2 parts of polymethylsilsesquioxane, and 0.2-0.4 parts of aluminum hydroxide.

7. The method for preparing a refreshing sunscreen lotion according to claim 1, characterized in that, In step S2, the moisturizing emulsion, by weight, consists of 10.0-13.0 parts water, 7.02-9.14 parts humectant, 2.5-3.5 parts emulsifier, and 0.2-0.4 parts distearate dimethylammonium lithium montmorillonite.

8. The method for preparing a refreshing sunscreen lotion according to claim 1, characterized in that, In step S3, the refreshing sunscreen lotion, by weight, comprises 27.0-31.0 parts of oil-phase base raw materials, 11-15 parts of modified sunscreen powder dispersion obtained in step S1, 15.8-19.7 parts of oil-soluble sunscreen agent, 0.8-1.2 parts of water-based sunscreen agent, 2.5-3.51 parts of whitening ingredient, 19.72-26.04 parts of moisturizing emulsifier obtained in step S2, 9-11 parts of ethanol, 0.7-1.1 parts of skin protectant, 0.8-1.2 parts of skin feel modifier, 0.35-0.45 parts of preservative, 0.8-1.2 parts of film-forming agent, 0.7-0.9 parts of sodium chloride, and 0.08-0.12 parts of fragrance.

9. The method for preparing a refreshing sunscreen lotion according to claim 1, characterized in that, The oil-phase base raw material, by weight, consists of 20-22 parts of polydimethylsiloxane, 7-9 parts of isododecane, and 0.08-0.12 parts of propylene glycol carbonate; the oil-soluble sunscreen agent, by weight, consists of 8.0-8.5 parts of ethylhexyl methoxycinnamate, 3.5-4.5 parts of ethylhexyl salicylate, 2.0-3.0 parts of hexyl diethylaminohydroxybenzoylbenzoate, 1.5-2.5 parts of octocrylene, and 0.8-1.2 parts of bis-ethylhexyloxyphenol methoxyphenyl triazine; the antioxidant is butylated hydroxytoluene; and the water-based sunscreen agent is phenylbenzimidazole sulfonic acid.

10. A refreshing sunscreen lotion prepared by the method of any one of claims 1-9.

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