Moisturizing, soothing, refreshing, light, thin and easy-to-smear sunscreen rod

Abstract

The invention discloses a moisturizing, soothing, refreshing, light, thin and easy-to-smear sunscreen rod, and belongs to the technical field of cosmetics. According to the sunscreen stick prepared by the invention, the polymer (ethylhexyl acrylate / methyl methacrylate copolymer) is firstly mixed with the ultraviolet absorbent for coating, so that the SPF value is increased, and meanwhile, the damage of the ultraviolet absorbent to the skin is avoided; meanwhile, the plant extracts (centella asiatica, aloe and saussurea involucrata) and a mixed system of bisabolol and menthol are mixed and matched with each other to achieve synergistic interaction, so that the moisturizing and soothing effects are achieved. In addition, the formula and the content of the grease and the thickening agent can be further optimized, and the prepared sunscreen stick is lighter, thinner and easy to smear.

Description

Technical Field

[0001] This invention relates to a sunscreen stick that is moisturizing, soothing, refreshing, lightweight, and easy to apply, belonging to the field of cosmetic technology. Background Technology

[0002] Ultraviolet radiation poses various health risks to the skin, such as causing sunburn, tanning, premature aging, and increasing the risk of skin cancer. As people become increasingly health-conscious and concerned about their appearance, sun protection has become an essential part of daily life.

[0003] Sunscreen products block or absorb ultraviolet rays to prevent skin from tanning and sunburn. Whether in daily life or during outdoor activities, it's essential to use sunscreen appropriately to protect your skin. Currently, there are various types of sunscreen products, including sunscreen lotions, sprays, and sticks. Sunscreen sticks, with their high-melting-point wax / polyolefin framework, are solid at room temperature and are applied directly to the face or body. Compared to sunscreen lotions and sprays, sunscreen sticks eliminate concerns about leakage, can be carried on airplanes, and can be applied with a single twist, leaving your hands clean when reapplying. They offer advantages such as portability and ease of application.

[0004] However, existing sunscreen sticks still have some significant drawbacks. For example, to improve water resistance, their formulas often contain 15%–25% wax and 40%–60% non-polar oils, resulting in high occlusion after application and a tendency to cause skin problems such as closed comedones and inflammatory papules. Furthermore, existing sunscreen sticks primarily focus on enhancing sun protection, lacking moisturizing, soothing, and repairing functions. Additionally, due to the high wax content, sunscreen sticks require repeated rubbing to form a coating on the skin. Users often fail to achieve the desired coating thickness, resulting in a lower actual amount used per unit area and a sun protection effect far below the stated SPF. Increasing the amount of sunscreen agent added to improve the SPF would lead to excessive sunscreen usage, posing a potential risk to the skin. Current research suggests using polymer-encapsulated organic UV absorbers to improve their safety during use, but this has drawbacks such as a reduction in SPF.

[0005] Therefore, developing a sunscreen stick that combines high-efficiency UV protection, instant soothing, and low risk of acne breakouts has become a pressing technical challenge for the industry. Summary of the Invention

[0006] To address at least one of the aforementioned problems, the present invention provides a sunscreen stick that is moisturizing, soothing, refreshing, lightweight, and easy to apply, possessing functions such as moisturizing, soothing, refreshing, lightweight, and easy to apply.

[0007] The first objective of this invention is to provide a sunscreen stick that is moisturizing, soothing, refreshing, lightweight, and easy to apply. By weight, the sunscreen stick specifically comprises the following components: 40-50 parts oil, 10-15 parts thickener, 10-15 parts sunscreen agent, 5-8 parts polymer, 5-10 parts soothing ingredient, 4-8 parts plant extract, 0.1-1 part preservative, and 0.1-1 part antioxidant; wherein the plant extract is obtained by mixing Centella asiatica, Aloe vera, and Saussurea involucrata in a weight ratio of 2-3:1-2:1; the polymer is prepared by mixing 2-ethylhexyl acrylate monomer, methyl methacrylate monomer, crosslinking agent ethylene glycol dimethacrylate, and initiator azobisisobutyronitrile in a weight ratio of 55-65:25-35:4-6:0.5-1, and then, under the action of a protective gas, at 60-70 °C... o C. Stir and react for 20-30 hours to obtain the polymer.

[0008] In one embodiment of the present invention, the sunscreen agent is obtained by mixing trimethylsiloxysilicate, ethylhexyl salicylate, and polysiloxane-15 in a mass ratio of 1~1.5:1~2:1.

[0009] In one embodiment of the present invention, the oil is obtained by mixing squalane and coconut oil ester in a ratio of 5 to 10:1.

[0010] In one embodiment of the present invention, the thickener is one or more of petrolatum, polyethylene wax, and microcrystalline wax; preferably, the thickener is a mixture of petrolatum, polyethylene wax, and microcrystalline wax in a mass ratio of 1:1 to 2:2 to 4.

[0011] In one embodiment of the present invention, the soothing component is a mixture of bisabolol and menthol in a ratio of 0.5 to 2:1.

[0012] In one embodiment of the present invention, the method for preparing the plant extract includes the following steps: pulverizing each raw material, adding an ethanol solution for extraction, filtering, and then extracting 50-80 ml of the extract. o Ethanol was recovered under reduced pressure until no alcohol odor remained, and the extract was obtained by drying.

[0013] In one embodiment of the present invention, the extraction method is reflux extraction; the concentration of ethanol is 50-85%; the amount of ethanol used is 3-10 times the total weight of the raw materials; and the number of extractions is 2-4.

[0014] In one embodiment of the present invention, the preservative is one or more of sodium benzoate, benzalkonium chloride, and methylparaben; preferably, the preservative is sodium benzoate.

[0015] In one embodiment of the present invention, the antioxidant includes one or more of tocopheryl acetate, tocopherol, ascorbate palmitate, and tetrahexyldecyl ascorbate; preferably, the antioxidant is tocopheryl acetate.

[0016] A second objective of this invention is to provide a method for preparing the sunscreen stick, comprising the following steps: Includes the following steps: S1. Mix 40%~60% of the oil and thickener, and heat to 80~90 degrees Celsius. o C. Stir well and cool to 50-60°C. o C yields the first oil phase; S2. Mix the remaining grease and polymer, and heat to 80-90°C. o C. Stir well and cool to 50-70°C. o After C, sunscreen is added, and the mixture is sheared and dispersed to obtain the second oil phase; S3. Mix the first oil phase and the second oil phase, and stir until homogeneous; S4. Add soothing ingredients, plant extracts, preservatives, and antioxidants, and stir well. S5. Injection molding, cooling and forming, demolding to obtain the sunscreen stick.

[0017] In one embodiment of the invention, the polymer is pulverized to 60-100 mesh before being mixed with oil.

[0018] In one embodiment of the present invention, in step S2, the shear dispersion is performed at a rotation speed of 7000~9000 rpm.

[0019] Advantages and effects of the present invention: The sunscreen stick prepared by this invention utilizes a polymer (ethylhexyl acrylate / methyl methacrylate copolymer) first mixed with a UV absorber for coating, which improves the SPF value while avoiding skin damage from the UV absorber. Simultaneously, this invention employs a mixture of plant extracts (centella asiatica, aloe vera, snow lotus) and a blend of bisabolol and menthol, which work synergistically to achieve moisturizing and soothing effects. Furthermore, this invention allows for further optimization of the formulation and content of oils and thickeners, resulting in a thinner and easier-to-apply sunscreen stick. Detailed Implementation

[0020] (1) Experimental materials: All raw materials used in the examples are commercially available.

[0021] (2) Evaluation method: a. Sun Protection Factor (SPF): The SPF values ​​of each sample were tested according to the method disclosed in T / CAFFCI 78-2024 "Prediction and Determination Method of Sunscreen Cosmetics Sun Protection Index (SPF Value) (Ultraviolet Light Variation Method)".

[0022] b. Moisturizing: Volunteer eligibility: Applicants must be between 20 and 45 years old, without serious systemic diseases, immunodeficiency or autoimmune diseases, active allergic diseases, a history of severe allergies to cosmetics, and have not used hormonal drugs or immunosuppressants in the past month. Applicants must not have scars, pigmentation, atrophy, port-wine stains, or other blemishes at the skin test site that would affect the test results, must not have participated in other clinical trials, must use the test substance as required and have complete documentation, and must sign an informed consent form before the test. A total of 30 qualified volunteers were selected, and samples were used on each volunteer.

[0023] Experimental method: Subjects were kept under constant temperature and humidity (temperature (21±1)). o Sit quietly for 30 minutes in an environment with humidity (40-60%), and mark two circular areas with a diameter of 18 mm on the corresponding positions on the inner sides of the left and right forearms. Do not drink water or beverages during this period. The test sites should be exposed and placed in the test position, and kept relaxed.

[0024] The product application area and blank control area should be randomly distributed in the calibrated areas of the left and right arms, with the test sample concentration set at (2.0±0.1) mg / cm³. 2 The sample was applied for the first time, and the sample was evenly applied to the test area. The actual amount of sample applied was recorded. Subjects were required to apply the sample on time and in the correct amount every day. After adjusting the instrument according to the instruction manual of the capacitance method skin moisture meter, the product area and the control area were measured. Each area was measured three times in parallel. The initial value (0h) of each test area was measured first, and then the skin moisture content of the test area and the control area was measured after the set time (1h, 3h).

[0025] c. Evaluation of soothing and repairing efficacy: Volunteer eligibility: Applicants must be between 20 and 45 years old, without serious systemic diseases, immunodeficiency or autoimmune diseases, active allergic diseases, a history of severe allergies to cosmetics, and have not used hormonal drugs or immunosuppressants in the past month. Applicants must not have scars, pigmentation, atrophy, port-wine stains, or other blemishes at the skin test site that would affect the test results, must not have participated in other clinical trials, must use the test substance as required and have complete documentation, and must sign an informed consent form before the test. A total of 30 qualified volunteers were selected, and samples were used on each volunteer.

[0026] Experimental method: Subjects were kept under constant temperature and humidity (temperature (21±1)). oSit quietly for 30 minutes in an environment with humidity (40-60%), and mark two circular areas with a diameter of 18 mm on the corresponding positions on the inner sides of the left and right forearms. Do not drink water or beverages during this period. The test sites should be exposed and placed in the test position, and kept relaxed.

[0027] First, the baseline values ​​of the two regions were measured. Then, a closed patch test was performed on the inner side of both forearms with a mass fraction of 1% sodium dodecyl sulfate (SLS) solution for 24 h to induce erythema. The right side region was the experimental group. The test sample was measured at (2.0±0.1) mg / cm³. 2 The amount of product used was applied for the first application. The sample was evenly applied to the right test area, while the left hand area served as the control group. The actual amount of product applied was recorded. Subjects were required to apply the product on time and in the correct amount every day. From day 1 to day 10, subjects in the experimental group used the test product on the right hand area in the morning and evening, while the left hand area served as the control group and no product was used. To conduct soothing and repair experimental data testing: Skin parameters, including transepidermal water loss (TEWL) and skin red pigment content, were measured on the left and right hands at 1, 5, and 10 days after using the test product. Testing of the same subject must be performed using the same instrument by the same tester, and the test probe should be cleaned between measurements.

[0028] Example 1: Preparation of plant extracts: Take 25g of Centella asiatica, 15g of Aloe vera, and 10g of Saussurea involucrata, crush them, add 300ml of 75% ethanol solution for reflux extraction, collect the extract, filter, and extract the residue again. Extract a total of 3 times, combine the extracts, and dilute 60ml of the extract. o Ethanol was recovered under reduced pressure until no alcohol odor remained, and the extract was obtained by drying.

[0029] Polymer preparation: 2-Ethylhexyl acrylate monomer, methyl methacrylate monomer, crosslinking agent ethylene glycol dimethacrylate, and initiator azobisisobutyronitrile were mixed in a mass ratio of 60:30:5:0.8 and heated at 70°C under a protective gas atmosphere. o C. Stir and react for 24 hours to obtain the polymer. Crush the polymer to 80 mesh for later use.

[0030] Preparation of sunscreen stick: Mix 40g of squalane and 5g of coconut oil ester evenly to obtain a mixed oil. Take 20g of the mixed oil, add 2g of petrolatum, 2g of polyethylene wax, and 8g of microcrystalline wax, and mix. Heat to 85°C. o C. Stir until homogeneous to obtain the first oil phase, then cool to 60°C. o C is reserved; add polymer powder to the remaining mixed oils and heat to 85°C. o C. Stir well and cool to 60°C. oAfter step C, add 12g of sunscreen agent obtained by mixing trimethylsiloxysilicate, ethylhexyl salicylate, and polysiloxane-15 in a mass ratio of 1:1:1, and shear and disperse at 8000rpm to obtain the second oil phase; mix the first and second oil phases evenly; add 4g of bisabolol, 4g of menthol, 6g of plant extract, 0.5g of sodium benzoate, and 0.5g of tocopheryl acetate, and stir evenly; then mold, cool and shape, and demold to obtain the sunscreen stick.

[0031] The sunscreen stick prepared in Example 1 was heated at 37°C. o After being stored in a constant temperature chamber for 30 days, the soothing efficacy was evaluated, and the results are shown in Table 1.

[0032] Table 1

[0033] Example 2: Preparation of plant extracts: Take 20g of Centella asiatica, 15g of Aloe vera, and 15g of Saussurea involucrata, crush them, add 300ml of 75% ethanol solution for reflux extraction, collect the extract, filter, and extract the residue again. Extract a total of 3 times, combine the extracts, and dilute 60ml of the extract. o Ethanol was recovered under reduced pressure until no alcohol odor remained, and the extract was obtained by drying.

[0034] Polymer preparation: 2-Ethylhexyl acrylate monomer, methyl methacrylate monomer, crosslinking agent ethylene glycol dimethacrylate, and initiator azobisisobutyronitrile were mixed in a mass ratio of 60:30:5:0.8 and heated at 70°C under a protective gas atmosphere. o C. Stir and react for 24 hours to obtain the polymer. Crush the polymer to 80 mesh for later use.

[0035] Preparation of sunscreen stick: Mix 40g of squalane and 5g of coconut oil ester evenly to obtain a mixed oil. Take 25g of the mixed oil, add 2g of petrolatum, 2g of polyethylene wax, and 8g of microcrystalline wax, and mix. Heat to 85°C. o C. Stir until homogeneous to obtain the first oil phase, then cool to 60°C. o C is reserved; add polymer powder to the remaining mixed oils and heat to 85°C. o C. Stir well and cool to 60°C. o After step C, add 12g of sunscreen agent obtained by mixing trimethylsiloxysilicate, ethylhexyl salicylate, and polysiloxane-15 in a mass ratio of 1:1:1, and shear and disperse at 8000rpm to obtain the second oil phase; mix the first and second oil phases evenly; add 4g of bisabolol, 4g of menthol, 6g of plant extract, 0.5g of sodium benzoate, and 0.5g of tocopheryl acetate, and stir evenly; then mold, cool and shape, and demold to obtain the sunscreen stick.

[0036] Example 3: Preparation of plant extracts: Take 25g of Centella asiatica, 15g of Aloe vera, and 10g of Saussurea involucrata, crush them, add 300ml of 75% ethanol solution for reflux extraction, collect the extract, filter, and extract the residue again. Extract a total of 3 times, combine the extracts, and dilute 60ml of the extract. o Ethanol was recovered under reduced pressure until no alcohol odor remained, and the extract was obtained by drying.

[0037] Polymer preparation: 2-Ethylhexyl acrylate monomer, methyl methacrylate monomer, crosslinking agent ethylene glycol dimethacrylate, and initiator azobisisobutyronitrile were mixed in a mass ratio of 60:30:5:0.8 and heated at 70°C under a protective gas atmosphere. o C. Stir and react for 24 hours to obtain the polymer. Crush the polymer to 80 mesh for later use.

[0038] Preparation of sunscreen stick: Mix 40g of squalane and 5g of coconut oil ester evenly to obtain a mixed oil. Take 20g of the mixed oil, add 3g of petrolatum, 3g of polyethylene wax, and 6g of microcrystalline wax, mix, and heat to 85°C. o C. Stir until homogeneous to obtain the first oil phase, then cool to 60°C. o C is reserved; add polymer powder to the remaining mixed oils and heat to 85°C. o C. Stir well and cool to 60°C. o After step C, add 12g of sunscreen agent obtained by mixing trimethylsiloxysilicate, ethylhexyl salicylate, and polysiloxane-15 in a mass ratio of 1:1:1, and shear and disperse at 8000rpm to obtain the second oil phase; mix the first and second oil phases evenly; add 5g of bisabolol, 4g of menthol, 5g of plant extract, 0.5g of sodium benzoate, and 0.5g of tocopheryl acetate, and stir evenly; then mold, cool and shape, and demold to obtain the sunscreen stick.

[0039] Comparative Example 1: Except for the absence of plant extracts, the other steps were the same as in Example 1, and the sunscreen stick was prepared.

[0040] The sunscreen stick prepared in Comparative Example 1 was heated at 37°C. o After being stored in a constant temperature chamber for 30 days, the soothing efficacy was evaluated, and the results are shown in Table 2.

[0041] Table 2

[0042] Comparative Example 2: Except for changing the raw materials in the plant extract to 30g of Centella asiatica and 20g of aloe vera, the other steps are the same as in Example 1, and the sunscreen stick is prepared.

[0043] The sunscreen stick prepared in Comparative Example 2 was heated at 37°C. o After being stored in a constant temperature chamber for 30 days, the soothing efficacy was evaluated, and the results are shown in Table 3.

[0044] Table 3

[0045] Comparative Example 3: Except for omitting menthol and adjusting the amount of bisabolol to 8g, the other steps are the same as in Example 1 to prepare the sunscreen stick.

[0046] The sunscreen stick prepared in Comparative Example 3 was heated at 37°C. o After being stored in a constant temperature chamber for 30 days, the soothing efficacy was evaluated, and the results are shown in Table 4.

[0047] Table 4

[0048] By comparing the data from the soothing experiments of Example 1 and Comparative Examples 1-3, it can be found that the sunscreen stick in Example 1 showed better skin recovery after 10 days, indicating that the sunscreen stick in Example 1 can repair the skin barrier, improve skin erythema, and has a soothing and repairing effect on damaged skin; while the sunscreen sticks in Comparative Examples 1-3 also had a certain soothing effect on the skin after use, but the effect was not as good as that of the sunscreen stick in Example 1.

[0049] Comparative Example 4: In the preparation of the sunscreen stick, no polymer powder was added, and the other steps were the same as in Example 1, and the sunscreen stick was prepared.

[0050] Test example: The sunscreen sticks prepared in Examples 1-3 and Comparative Examples 1-4 were tested at 37°C. o After being stored in a constant temperature chamber for 30 days, the sun protection and moisturizing effects were evaluated, and the results are shown in Table 5.

[0051] Table 5

[0052] As shown in Table 5, the sunscreen sticks prepared in Examples 1-3 all have good sun protection and moisturizing properties. Comparing the test results of the examples with Comparative Example 1, it can be found that when no plant extracts are added to the sunscreen sticks, the performance of the sunscreen sticks is significantly reduced. Comparing the test results of the examples with Comparative Examples 2-3, it can be found that the moisturizing effect of the sunscreen sticks is only good when the raw materials of the plant extracts are Centella asiatica, aloe vera, and snow lotus, and the soothing ingredients are bisabolol and menthol.

[0053] Comparing the test results of the examples and Comparative Example 4, it was found that when the polymer prepared in Example 1 was not added, the sun protection effect of the sunscreen stick in Comparative Example 4 decreased significantly after 30 days of storage, while the sun protection effect of the example was better.

[0054] The specific embodiments described above further illustrate the technical problems, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sunscreen stick that is moisturizing, soothing, refreshing, lightweight, and easy to apply, characterized in that: By weight, the sunscreen stick specifically comprises the following components: The mixture comprises 40-50 parts oil, 10-15 parts thickener, 10-15 parts sunscreen, 5-8 parts polymer, 5-10 parts soothing ingredients, 4-8 parts plant extracts, 0.1-1 parts preservative, and 0.1-1 parts antioxidant; wherein the plant extract is obtained by mixing Centella asiatica, Aloe vera, and Saussurea involucrata in a mass ratio of 2-3:1-2:1; the polymer is prepared by mixing 2-ethylhexyl acrylate monomer, methyl methacrylate monomer, crosslinking agent ethylene glycol dimethacrylate, and initiator azobisisobutyronitrile in a mass ratio of 55-65:25-35:4-6:0.5-1, and under the action of a protective gas at 60-70 °C. o C. Stir and react for 20-30 hours to obtain the polymer.

2. The sunscreen stick according to claim 1, characterized in that, The sunscreen agent is obtained by mixing trimethylsiloxysilicate, ethylhexyl salicylate, and polysiloxane-15 in a mass ratio of 1~1.5:1~2:

1.

3. The sunscreen stick according to claim 1, characterized in that, The oil is obtained by mixing squalane and coconut oil ester in a ratio of 5 to 10:

1.

4. The sunscreen stick according to claim 1, characterized in that, The thickener is one or more of petrolatum, polyethylene wax, and microcrystalline wax; preferably, the thickener is a mixture of petrolatum, polyethylene wax, and microcrystalline wax in a mass ratio of 1:1 to 2:2 to 4.

5. The sunscreen stick according to claim 1, characterized in that, The soothing ingredients are a mixture of bisabolol and menthol in a ratio of 0.5 to 2:

1.

6. The sunscreen stick according to claim 1, characterized in that, The preparation method of the plant extract includes the following steps: pulverizing each raw material, adding ethanol solution for extraction, filtering, and then extracting 50-80 ml of the extract. o Ethanol was recovered under reduced pressure until no alcohol odor remained, and the extract was obtained by drying. The extraction method is reflux extraction; the concentration of ethanol is 50-85%; the amount of ethanol used is 3-10 times the total weight of the raw material; the number of extractions is 2-4.

7. The sunscreen stick according to claim 1, characterized in that, The preservative is one or more of sodium benzoate, benzalkonium chloride, and methylparaben; the antioxidant includes one or more of tocopheryl acetate, tocopherol, ascorbate palmitate, and tetrahexyldecyl ascorbate.

8. A method for preparing a sunscreen stick according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Mix 40%~60% of the oil and thickener, and heat to 80~90 degrees Celsius. o C. Stir well and cool to 50-60°C. o C yields the first oil phase; S2. Mix the remaining grease and polymer, and heat to 80-90°C. o C. Stir well and cool to 50-70°C. o After C, sunscreen is added, and the mixture is sheared and dispersed to obtain the second oil phase; S3. Mix the first oil phase and the second oil phase, and stir until homogeneous; S4. Add soothing ingredients, plant extracts, preservatives, and antioxidants, and stir well. S5. Injection molding, cooling and forming, demolding to obtain the sunscreen stick.

9. The preparation method according to claim 8, characterized in that, The polymer is pulverized to 60-100 mesh before being mixed with oil.

10. The preparation method according to claim 8, characterized in that, In step S2, shear dispersion is performed at a rotation speed of 7000~9000 rpm.

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