Hydrogel containing all-type sun-screening agent microbeads, preparation method and application

Abstract

The invention relates to hydrogel containing all-type sun-screening agent microbeads, a preparation method and application, and belongs to the technical field of sun screening. Mixing, heating and dissolving the oil-soluble organic sun-screening agent to obtain the sun-screening oil; the preparation method comprises the following steps: mixing a sodium alginate solution, a PVA solution and an inorganic sun-screening agent (zinc oxide and titanium dioxide) to form a turbid liquid, and uniformly stirring to form a first mixture; preparing oil-in-water microspheres from the obtained sunscreen oil and the first mixture through a microfluidic technology, and dripping the oil-in-water microspheres into a calcium chloride solution to form light yellow sunscreen microspheres; adding carbomer sodium into water to form gel, then adding the water-soluble organic sun-screening agent, adding the pH regulator while heating and dissolving until the solution is transparent, then adding the active substance, and continuously stirring until the mixture is uniformly mixed to obtain a third mixture; adding a thickening agent to prepare hydrogel; and adding the sunscreen microbeads into the hydrogel to obtain a dispersion system containing all types of sunscreen microbeads. The invention solves the technical problem that the product in the existing sunscreen system is greasy and easily causes anaphylactic reaction.

Description

Technical Field

[0001] The present invention relates to the field of sunscreen technology, and in particular to a method for preparing all types of sunscreen microbeads. Background Art

[0002] Ultraviolet radiation can cause skin sunburn, skin erythema, pigmentation and aging, which not only affects the appearance, but also causes harm to health. Sunscreen products are an important means to prevent skin tanning and sunburn. They are loved by consumers and the market for sunscreen products has gradually increased in recent years. Sunscreen agents are the core functional raw materials of sunscreen products, which are mainly divided into two categories: organic sunscreen agents and inorganic sunscreen agents. Among them, organic sunscreen agents can be divided into oil-soluble sunscreen agents (such as ethylhexyl methoxycinnamate octocrylene) and water-soluble sunscreen agents (such as phenylbenzimidazole sulfonic acid, disodium phenyl dibenzimidazole tetrasulfonate). This type of sunscreen agent is generally a carbonyl conjugated or heterocyclic aromatic organic compound that can absorb ultraviolet rays and then convert them into radiation that is safer for human skin. Inorganic sunscreen agents include zinc oxide and titanium dioxide, which mainly rely on reflecting and scattering ultraviolet rays to achieve the effect of sun protection, but they are neither soluble in water nor in oil.

[0003] People's choice of sunscreen products is usually determined by SPF value, PA value, and skin feel. Most of the sunscreen raw materials allowed for use in my country are oil-soluble, so the common sunscreen product formulations are mainly oil-in-water systems, which have problems such as greasy products and heavy textures. Oil-soluble sunscreens are also prone to toxicity and can easily cause allergic reactions when in contact with the skin. Although water-in-oil sunscreen products have a better skin feel, the SPF value is not high due to the limitation on the amount of sunscreen added, which cannot meet people's daily sun protection needs, and seriously limits the promotion of water-in-oil sunscreen products in the market. At the same time, inorganic sunscreens such as titanium dioxide and zinc oxide cannot be well dispersed in water-in-oil formulations or oil-in-water formulations, which makes them easy to aggregate and affect the sunscreen effect. In addition, both oil-in-water sunscreen products and water-in-oil sunscreen products are prone to stratification after long-term storage and have poor stability.

[0004] Microfluidics is a science and technology for manipulating fluids in microchannels. It has the characteristics of miniaturization and integration. It can wrap the core material in the wall material to form microspheres with controllable size and independent of each other by precisely controlling the flow of fluid, thereby isolating the core material from the surrounding environment. Therefore, the present invention proposes to use inorganic sunscreen as wall material, and use microfluidics technology to wrap oil-soluble organic sunscreen as core material in the wall material to make microbeads. At the same time, water-soluble organic sunscreen and various functional ingredients are dissolved in hydrogel, thereby forming a hydrogel sunscreen product containing all types of sunscreen and various cosmetic functional ingredients. The microspheres generated by the above method are uniform and stable, and can effectively avoid the stratification phenomenon of long-term placement. The oil-soluble sunscreen is wrapped in the wall material, which can effectively isolate it from water, improve product stability, and further reduce the irritation and toxic side effects that may be caused by organic sunscreen to the skin, thereby improving product stability and safety. In addition, since the hydrogel sunscreen product contains water-soluble organic sunscreens, oil-soluble organic sunscreens, inorganic sunscreens and a variety of cosmetic functional ingredients, it can ensure the stable presence of all types of sunscreens and cosmetic functional ingredients while ensuring a refreshing skin feel, making the product have excellent sun protection performance and versatility. Summary of the invention

[0005] The present invention provides a hydrogel containing all types of sunscreen microbeads, a preparation method and an application thereof, which solve the technical problem that products in the existing sunscreen system are greasy and easily cause allergic reactions.

[0006] The technical solution of the present invention:

[0007] A method for preparing a hydrogel containing all types of sunscreen microbeads comprises the following steps:

[0008] Step 1: Mixing and heating the oil-soluble organic sunscreen agent to dissolve to obtain a sunscreen oil;

[0009] Step 2: Mix the sodium alginate solution, the PVA solution, the zinc oxide, and the titanium dioxide to form a suspension, and stir evenly to form a first mixture;

[0010] Step 3: preparing the sunscreen oil obtained in step 1 and the first mixture into oil-in-water microspheres by microfluidics technology and dropping the microspheres into a calcium chloride solution to form light yellow sunscreen microspheres;

[0011] Step 4: adding sodium carbomer into water to form a gel, then adding a water-soluble organic sunscreen, and adding a pH adjuster while heating to dissolve until the solution is transparent, to obtain a second mixture;

[0012] Step 5: Add the active substance to the second mixture obtained in step 4, and stir continuously until the mixture is uniform to obtain a third mixture;

[0013] Step 6: adding a thickener to the third mixture obtained in step 5 to prepare a hydrogel;

[0014] Step 7: Add the sunscreen microbeads obtained in step 3 into the hydrogel to obtain a dispersion system containing all types of sunscreen microbeads.

[0015] Preferably, the composition and ratio of the oil-soluble organic sunscreen in step 1 are: ethylhexyl methoxycinnamate (OMC): ethylhexyl salicylate (EHS): octocrylene (OCR): diethylaminohydroxybenzoyl hexyl benzoate (DHHB): bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT) = 5-10: 1-5: 4-10: 1-5: 1-5;

[0016] Preferably, the heating temperature in step 1 is 60-80°C.

[0017] Preferably, the mass concentrations of the sodium alginate solution and the PVA solution in step 2 are both 1%-3%; the mass ratio of the sodium alginate solution to the PVA solution is 1-5:1; and the zinc oxide and titanium dioxide each account for 3%-5% of the total solution mass.

[0018] Preferably, in step 3, the pushing speed of the sunscreen oil is 0.1-0.25 mL / min, the pushing speed of the first mixture is 0.3-0.8 mL / min, and the flow rate ratio is 1:2-5; the mass concentration of the calcium chloride solution is 5%-10%.

[0019] Preferably, the mass concentration of sodium carbomer in the gel in step 4 is 0.5-1%; the composition and ratio of the water-soluble organic sunscreen are: phenylbenzimidazole sulfonic acid: disodium phenyl dibenzimidazole tetrasulfonate (DPDT) = 5:8-10; the mass ratio of sodium carbomer to the water-soluble organic sunscreen is 1:10-36. The heating temperature is 70-90°C; and the pH adjuster is triethanolamine or sodium hydroxide.

[0020] Preferably, the active substance in step 5 is a plant extract such as Dendrobium candidum, chamomile, calendula, or carbon dots, and the mass concentration of the active substance in the third mixture is 0.1%-1%.

[0021] Preferably, the thickeners in step 6 are xanthan gum and hydroxyethyl cellulose, and the amount of the thickener added is 0.1%-0.5% of the mass of the third mixture, wherein xanthan gum accounts for 1-2 parts and hydroxyethyl cellulose accounts for 1-3 parts.

[0022] Preferably, in step 7, the mass ratio of the light yellow sunscreen microbeads to the hydrogel is 1:2-10.

[0023] The present invention provides a sunscreen technology, which uses inorganic sunscreen as a wall material to embed an oil-soluble organic chemical sunscreen, and uses a refreshing hydrogel as the main solvent. By adding functional ingredients such as water-soluble organic chemical sunscreens, plant extracts and carbon dots, the SPF value and soothing effect are further improved. The oil-soluble organic sunscreen is encapsulated in a ball to avoid separation caused by long-term storage of oil-water mixture, thereby significantly improving product stability. This method covers all types of sunscreens, including inorganic sunscreens, oil-soluble organic sunscreens and water-soluble organic sunscreens. The sunscreen has a high content and good broad spectrum, and has excellent ultraviolet absorption performance in both UVA and UVB bands, and has a significant sunscreen effect. In addition, the encapsulation of the oil-soluble sunscreen by the hydrogel not only reduces the toxicity, but also reduces the incidence of skin irritation and allergic reactions while ensuring a refreshing skin feel, further improving the safety and applicability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the sunscreen microbeads of Example 1.

[0025] Figure 2 The sunscreen microbeads of Example 1 are shown under a microscope.

[0026] Figure 3 This is the sunscreen microbeads of Comparative Example 1.

[0027] Figure 4 This is the sunscreen microbeads of Comparative Example 1 under a microscope.

[0028] Figure 5 is the ultraviolet absorbance of the embodiment.

[0029] Figure 6 The UV transmittance of Example 1 and Example 2. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below with reference to the examples, but the embodiments of the present invention are not limited thereto.

[0031] Example 1

[0032] (1) Preparation of sunscreen microbeads

[0033] Accurately weigh 9g of ethylhexyl methoxycinnamate, 3g of ethylhexyl salicylate, 8g of octocrylene, 3g of diethylaminohydroxybenzoyl hexyl benzoate, and 3g of bis-ethylhexyloxyphenol methoxyphenyl triazine in a beaker, heat in a constant temperature water bath at 80°C, and stir continuously to dissolve into sunscreen oil for later use. Weigh 1g of sodium alginate and PVA respectively and dissolve in 100mL of deionized water to prepare a 1% dilute solution. The two are mixed in a mass ratio of 3:1 to form a 100g solution, stir evenly, then add 3g of zinc oxide and 4g of titanium dioxide powder, stir well, and ultrasonicate for half an hour to obtain a uniformly dispersed suspension. Weigh 5g of calcium chloride powder and dissolve in 100mL of deionized water to prepare a 5% calcium chloride solution for later use. The above-mentioned sunscreen oil and suspension were added into 30mL syringes respectively, fixed on the syringe pump, the suspension was pushed at a rate of 0.6mL / min, and the sunscreen oil was pushed at a rate of 0.2mL / min, with a flow rate ratio of 3:1. The two automatically generated water-in-oil microbeads in the microchannel, which dripped into 5% calcium chloride solution at the outlet. Sodium alginate was converted into calcium alginate, and a gel shell was formed to generate light yellow sunscreen microbeads for standby use.

[0034] (2) Preparation of carbon dots

[0035] 30 ml of carrot juice was measured and placed in a hydrothermal autoclave, reacted at 180°C for 4 h, cooled naturally, and taken out to obtain carrot carbon dots.

[0036] (3) Preparation of hydrogel

[0037] Weigh 0.25g of sodium carbomer powder and pour it into 50mL of deionized water, heat and dissolve to form a gel. Weigh 3g of phenylbenzimidazole sulfonic acid and 4g of disodium phenyl dibenzimidazole tetrasulfonate and add them to the gel. Add 1mol / L sodium hydroxide solution while stirring at 80°C. After the gel turns into a milky white transparent solution, stop adding sodium hydroxide solution and wait for the solution to cool. Add 0.15g of calendula extract, 0.25g of Dendrobium officinale solution, and 0.1g of carrot carbon dot solution and mix well. Add 0.1g of xanthan gum and 0.15g of hydroxyethyl cellulose to swell, dissolve in a homogenizer at 4000 rpm to obtain a dispersion, eliminate bubbles by ultrasound, and let stand to form a gel.

[0038] (4) Preparation of hydrogel containing all types of sunscreen microbeads

[0039] 20 g of sunscreen microbeads were added one by one to 50 g of hydrogel, and stirred to allow the microbeads to be fully dispersed in the gel to prepare full-type sunscreen microbeads I.

[0040] Example 2

[0041] (1) Preparation of sunscreen microbeads

[0042] Accurately weigh 9g of ethylhexyl methoxycinnamate, 3g of ethylhexyl salicylate, 8g of octocrylene, 3g of diethylaminohydroxybenzoyl hexyl benzoate, and 3g of bis-ethylhexyloxyphenol methoxyphenyl triazine in a beaker, heat in a constant temperature water bath at 80°C, and stir continuously to dissolve into sunscreen oil for later use. Weigh 1g of sodium alginate and PVA respectively and dissolve in 100mL of deionized water to prepare a 1% dilute solution. The two are mixed in a mass ratio of 3:1 to form a 100g solution, stir evenly, then add 3g of zinc oxide and 4g of titanium dioxide powder, stir well, and ultrasonicate for half an hour to obtain a uniformly dispersed suspension. Weigh 5g of calcium chloride powder and dissolve in 100mL of deionized water to prepare a 5% calcium chloride solution for later use. The above-mentioned sunscreen oil and suspension were added into 30mL syringes respectively, fixed on the syringe pump, the suspension was pushed at a rate of 0.6mL / min, and the sunscreen oil was pushed at a rate of 0.2mL / min, with a flow rate ratio of 3:1. The two automatically generated water-in-oil microbeads in the microchannel, which dripped into 5% calcium chloride solution at the outlet. Sodium alginate was converted into calcium alginate, and a gel shell was formed to generate light yellow sunscreen microbeads for standby use.

[0043] (2) Preparation of hydrogel

[0044] Weigh 0.25g of sodium carbomer powder and pour it into 50mL of deionized water, heat and dissolve to form a gel. Weigh 3g of phenylbenzimidazole sulfonic acid and 4g of disodium phenyl dibenzimidazole tetrasulfonate and add them to the gel. Add 1mol / L sodium hydroxide solution while stirring at 80°C. After the gel turns into a milky white transparent solution, stop adding sodium hydroxide solution and wait for the solution to cool. Add 0.25g of calendula extract and 0.25g of Dendrobium officinale solution and mix well. Add 0.1g of xanthan gum and 0.15g of hydroxyethyl cellulose to swell, dissolve in a homogenizer at 4000 rpm to obtain a dispersion, eliminate bubbles by ultrasound, and let stand to form a gel.

[0045] (3) Preparation of hydrogel containing all types of sunscreen microbeads

[0046] Add 20 g of sunscreen microbeads to 50 g of hydrogel one by one, stir to allow the microbeads to be fully dispersed in the gel, and prepare full-type sunscreen microbeads II.

[0047] Example 3

[0048] (1) Preparation of sunscreen microbeads

[0049] Accurately weigh 5g of ethylhexyl methoxycinnamate, 5g of ethylhexyl salicylate, 6g of octocrylene, 5g of diethylaminohydroxybenzoyl hexyl benzoate, and 5g of bis-ethylhexyloxyphenol methoxyphenyl triazine in a beaker, heat in a 60°C constant temperature water bath, and stir continuously to dissolve into sunscreen oil for later use. Weigh 1g of sodium alginate and PVA respectively and dissolve in 100mL of deionized water to prepare a 1% dilute solution. The two are mixed in a mass ratio of 1:1 to form a 100g solution, stir evenly, then add 5g of zinc oxide and 5g of titanium dioxide powder, stir well, and ultrasonicate for half an hour to obtain a uniformly dispersed suspension. Weigh 5g of calcium chloride powder and dissolve in 100mL of deionized water to prepare a 5% calcium chloride solution for later use. The above-mentioned sunscreen oil and suspension were added into 30mL syringes respectively, fixed on the syringe pump, the suspension was pushed at a rate of 0.8mL / min, and the sunscreen oil was pushed at a rate of 0.2mL / min, with a flow rate ratio of 4:1. The two automatically generated water-in-oil microbeads in the microchannel, which dripped into 5% calcium chloride solution at the outlet. Sodium alginate was converted into calcium alginate, and a gel shell was formed to generate light yellow sunscreen microbeads for standby use.

[0050] (2) Preparation of carbon dots

[0051] 30 ml of carrot juice was measured and placed in a hydrothermal autoclave, reacted at 180°C for 4 h, cooled naturally, and taken out to obtain carrot carbon dots.

[0052] (3) Preparation of hydrogel

[0053] Weigh 0.5g of sodium carbomer powder and pour it into 50mL of deionized water, heat and dissolve to form a gel. Weigh 4g of phenylbenzimidazole sulfonic acid and 5g of disodium phenyl dibenzimidazole tetrasulfonate and add them to the gel. Add 1mol / L sodium hydroxide solution while stirring at 80°C. After the gel turns into a milky white transparent solution, stop adding sodium hydroxide solution and wait for the solution to cool. Add 0.35g of carrot carbon dot solution and mix well. Add 0.1g of xanthan gum and 0.15g of hydroxyethyl cellulose to swell, dissolve in a homogenizer at 4000 rpm to obtain a dispersion, eliminate bubbles by ultrasound, and let stand to form a gel.

[0054] (4) Preparation of hydrogel containing all types of sunscreen microbeads

[0055] Add 25 g of sunscreen microbeads one by one into 50 g of hydrogel and stir to allow the microbeads to be fully dispersed in the gel to prepare full-type sunscreen microbeads III.

[0056] Example 4

[0057] (1) Preparation of sunscreen microbeads

[0058] Accurately weigh 10g of ethylhexyl methoxycinnamate, 5g of ethylhexyl salicylate, 4g of octocrylene, 1g of diethylaminohydroxybenzoyl hexyl benzoate, and 1g of bis-ethylhexyloxyphenol methoxyphenyl triazine in a beaker, heat in a 70°C constant temperature water bath, and stir continuously to dissolve into sunscreen oil for later use. Weigh 2g of sodium alginate and PVA respectively and dissolve in 100mL of deionized water to prepare a 2% dilute solution. The two are mixed into a 100g solution at a mass ratio of 5:1, stirred evenly, and then 3g of zinc oxide and 3g of titanium dioxide powder are added. Stir well and ultrasonicate for half an hour to obtain a uniformly dispersed suspension. Weigh 5g of calcium chloride powder and dissolve in 100mL of deionized water to prepare a 5% calcium chloride solution for later use. The above-mentioned sunscreen oil and suspension were added into 30mL syringes respectively, fixed on the syringe pump, the suspension was pushed at a rate of 0.5mL / min, and the sunscreen oil was pushed at a rate of 0.25mL / min, with a flow rate ratio of 2:1. The two automatically generated water-in-oil microbeads in the microchannel, which dripped into 5% calcium chloride solution at the outlet. Sodium alginate was converted into calcium alginate, and a gel shell was formed to generate light yellow sunscreen microbeads for standby use.

[0059] (2) Preparation of carbon dots

[0060] 30 ml of carrot juice was measured and placed in a hydrothermal autoclave, reacted at 180°C for 4 h, cooled naturally, and taken out to obtain carrot carbon dots.

[0061] (3) Preparation of hydrogel

[0062] Weigh 0.25g of sodium carbomer powder and pour it into 50mL of deionized water, heat and dissolve to form a gel. Weigh 3g of phenylbenzimidazole sulfonic acid and 4g of disodium phenyl dibenzimidazole tetrasulfonate and add them to the gel. Add 1mol / L sodium hydroxide solution while stirring at 80°C. After the gel turns into a milky white transparent solution, stop adding sodium hydroxide solution and wait for the solution to cool. Add 0.15g of carrot carbon dot solution and mix well. Add 0.1g of xanthan gum and 0.15g of hydroxyethyl cellulose to swell, dissolve in a homogenizer at 4000 rpm to obtain a dispersion, eliminate bubbles by ultrasound, and let it stand to form a gel.

[0063] (4) Preparation of hydrogel containing all types of sunscreen microbeads

[0064] Add 10 g of sunscreen microbeads one by one into 50 g of hydrogel and stir to allow the microbeads to be fully dispersed in the gel to prepare full-type sunscreen microbeads IV.

[0065] Comparative Example 1 (Compared with Example 1, the zinc oxide and titanium dioxide powders were added in different ways)

[0066] (1) Preparation of sunscreen microbeads

[0067] Accurately weigh 9g ethylhexyl methoxycinnamate, 3g ethylhexyl salicylate, 8g octocrylene, 3g diethylaminohydroxybenzoyl hexyl benzoate, 3g bis-ethylhexyloxyphenol methoxyphenyl triazine, 3g zinc oxide, and 4g titanium dioxide in a beaker, heat in a constant temperature water bath at 80°C, and stir continuously to dissolve into sunscreen oil for later use. Weigh 1g sodium alginate and PVA separately and dissolve in 100mL deionized water to prepare a 1% dilute solution. Mix the two in a mass ratio of 3:1 to form a 100g solution and stir evenly. Weigh 5g calcium chloride powder and dissolve in 100mL deionized water to prepare a 5% calcium chloride solution for later use. The above-mentioned sunscreen oil and solution were added into 30mL syringes respectively, fixed on the syringe pump, the suspension was pushed at a rate of 0.6mL / min, and the sunscreen oil was pushed at a rate of 0.2mL / min, with a flow rate ratio of 3:1. The two automatically generated water-in-oil microbeads in the microchannel, which dripped into 5% calcium chloride solution at the outlet. Sodium alginate was converted into calcium alginate, and a gel shell was formed to generate light yellow sunscreen microbeads for standby use.

[0068] (2) Preparation of carbon dots

[0069] 30 ml of carrot juice was measured and placed in a hydrothermal autoclave, reacted at 180°C for 4 h, cooled naturally, and taken out to obtain carrot carbon dots.

[0070] (3) Preparation of hydrogel

[0071] Weigh 0.25g of sodium carbomer powder and pour it into 50mL of deionized water, heat and dissolve to form a gel. Weigh 3g of phenylbenzimidazole sulfonic acid and 4g of disodium phenyl dibenzimidazole tetrasulfonate and pour them into the gel. Add 1mol / L sodium hydroxide solution while stirring at 80°C. After the gel turns into a milky white transparent solution, stop adding sodium hydroxide solution and wait for the solution to cool. Add 0.15g of calendula extract, 0.25g of Dendrobium officinale solution, and 0.1g of carrot carbon dot solution and mix well. Add 0.1g of xanthan gum and 0.15g of hydroxyethyl cellulose to swell, dissolve in a homogenizer at 4000 rpm to obtain a dispersion, eliminate bubbles by ultrasound, and let stand to form a gel.

[0072] (4) Preparation of hydrogel containing all types of sunscreen microbeads

[0073] Add 20 g of sunscreen microbeads one by one into 50 g of hydrogel and stir to allow the microbeads to be fully dispersed in the gel to prepare full-type sunscreen microbeads V.

[0074] Comparative Example 2

[0075] (1) Preparation of oil phase

[0076] Mix 9g of ethylhexyl methoxycinnamate, 6g of 12-15 alkyl benzoate, 4g of titanium dioxide, 3g of zinc oxide, 3g of ethylhexyl salicylate, 8g of octocrylene, 3g of diethylaminohydroxybenzoyl hexyl benzoate, 3g of bis-ethylhexyloxyphenol methoxyphenyl triazine, 3g of glyceryl stearate, 3g of cyclomethicone, 2.5g of diethylaminohydroxybenzoyl hexyl benzoate, 2g of 4-methylbenzylidene camphor, 1g of cetyl alcohol, 1g of VP / hexadecene copolymer and 2g of polydimethylsiloxane, and heat to 80°C to dissolve.

[0077] (2) Preparation of aqueous phase

[0078] Mix 5g of butanediol, 3g of phenylbenzimidazole sulfonic acid, 4g of disodium phenyl dibenzimidazole tetrasulfonate, 2.5g of potassium cetyl phosphate, 0.3g of panthenol, 0.1g of carrot carbon dot solution, 0.15g of calendula extract, 0.25g of Dendrobium officinale extract, 0.2g of xanthan gum and 60g of deionized water, and heat to 80°C; add 0.1g of flavor, 0.1g of disodium EDTA and 0.01g of methylisothiazolinone, and stir well.

[0079] (3) Preparation of sunscreen lotion

[0080] In a 90°C water bath, the water phase was added dropwise to the oil phase while stirring. After the oil-water was completed, the sample was cooled and homogenized in a homogenizer at 4000 rpm to obtain sunscreen lotion VI.

[0081] In this example, the prepared sunscreen microspheres were preliminarily evaluated in comparison with commercially available sunscreens. The evaluation criteria included appearance, sunscreen effect, skin feel, and sensitivity.

[0082] External evaluation standard: The overall color of the sunscreen is uniform and there is no stratification, which is 10 points. Uneven color, stratification, and turbidity are 0 points. Sunscreen effect evaluation standard: Apply the same amount of different sunscreens and irradiate under the sun simulator. If erythema does not occur for a long time and the skin does not feel obvious, it is 10 points. If erythema occurs in a short time and the skin feels burning, it is 0 points. Skin sensitivity evaluation standard: Apply the same amount of different sunscreens evenly on the back of the hand. If it can be spread immediately without residue and is not greasy after application, it is 10 points. If there is a certain residue and the skin feels sticky, it is 0 points. Sensitivity evaluation standard: 8 hours after applying the sunscreen, there is no stuffy acne and no obvious feeling, which is 10 points. If acne occurs and itching is 0 points.

[0083] The evaluation results are shown in Table 1 below. Numbers 1, 2, 3, and 4 are all types of sunscreen microbeads I (Example 1), all types of sunscreen microbeads II (Example 2), all types of sunscreen microbeads V (Comparative Example 1), and sunscreen lotion VI (Comparative Example 2). Numbers 5 and 6 are commercially available sunscreens of different brands.

[0084] Table 1 Evaluation table

[0085] Group Appearance Sun protection effect Skin feel Sensitivity 1 (Example 1) 9.6 9.8 9.7 10 2 (Example 2) 9.6 9.2 9.6 10 3 (Comparative Example 1) 9.3 9.4 9.5 10 4 (Comparative Example 2) 9.4 9.4 9.1 10 5 (commercially available 1) 9.2 9.1 9.1 10 6 (commercially available 2) 9.1 9.1 9.0 10

[0086] As shown in Table 1, the sunscreen effects of all types of sunscreen microbeads and sunscreen lotions are better than those of commercially available sunscreens. By comparing Example 1 with Example 2, it is shown that the sunscreen effect is improved after adding carbon dots. Figure 1 and Figure 3 As shown, it is shown that using titanium dioxide and zinc oxide as shell materials can avoid the whitening phenomenon of sunscreen agents and improve the appearance. The water-in-oil type sunscreen microbeads prepared in Example 1 and Implementation 2 have better skin feel than the comparative example 2 and the traditional oil-in-water system sunscreen lotion system on the market. Comparison between Implementation 1 and Comparative Example 2 shows that under the same raw material conditions, the sunscreen microbeads prepared by microfluidic technology are better than sunscreen lotion. The sensitivity difference between the seven is not large, and there is no allergic reaction.

[0087] SPF value test of samples

[0088] Selected subjects: 10 people in total, 4 males, 6 females, aged 20-25, SPF value measurement results are shown in Table 2

[0089] Table 2 SPF values

[0090]

[0091] Conclusion: The human test results show that the SPF value is improved after adding carbon dots.

[0092] UV test: Use a UV spectrophotometer to test the product.

[0093] Depend on Figure 5 and Figure 6 It can be seen that after adding carbon dots to all types of sunscreen microbeads, UV absorption is enhanced and UV transmittance is reduced.

[0094] Irritation test of sunscreen patent

[0095] (1) Solution preparation

[0096] Prepare 25g of 1wt% sample solution, add 0.5wt%~1wt% Zein (0.125g~0.25g) thereto, stir the test solution at 25℃ for 2h, add 0.5wt% Zein first, if it is completely dissolved, add 0.5wt% Zein again, and make a blank control sample at the same time.

[0097] (2) Sample digestion

[0098] 10mL of the liquid sample with Zein added was taken and transferred into a dry 250mL nitrogen determination bottle, and 0.2g of copper sulfate, 3g of potassium sulfate and 20mL of sulfuric acid were added. After digestion for 2h in the UPT-XH10 intelligent constant temperature digestion furnace, the blue-green clear and transparent liquid obtained was the digestion solution. The control sample was a sample without Zein added, and the digestion solution control sample was obtained after the same operation.

[0099] (3) Nitrogen determination

[0100] Use UPT-K1600A Kjeldahl nitrogen analyzer, put in the nitrogen determination bottle with complete digestion, let steam evaporate for 5 minutes, and introduce all the evaporated nitrogen into the boric acid solution. Add methyl red-bromocresol green mixed indicator, and use the calibrated hydrochloric acid standard solution to titrate from blue-green to red.

[0101] (4) Data processing and judgment

[0102] N = 1000 * 0.0140 * C * (V1-V2) / V3. Where N is the mass fraction of nitrogen in the sample (g / L); V1 is the volume of hydrochloric acid standard solution consumed by sample titration (mL); V2 is the volume of hydrochloric acid standard solution consumed by blank titration (mL); C is the concentration of hydrochloric acid standard titration solution (mol·L -1 ), the concentration of the hydrochloric acid standard solution in this test is 0.1052 mol·L -1 ; V3—volume of sample solution with Zein added (mL); 0.0140 is 1 mol·L -1 1mL of hydrochloric acid standard solution is equivalent to grams of nitrogen.

[0103] By using the N value, irritation can be divided into three categories:

[0104]

[0105]

[0106] It can be seen from the table that Example 1 and Example 2 have no obvious irritation.

Claims

1. A method for preparing a hydrogel containing all types of sunscreen microbeads, characterized in that: The following steps are involved: Step 1: Mixing and heating the oil-soluble organic sunscreen agent to dissolve to obtain a sunscreen oil; Step 2: Mix the sodium alginate solution, the PVA solution, the zinc oxide, and the titanium dioxide to form a suspension, and stir evenly to form a first mixture; Step 3: preparing the sunscreen oil obtained in step 1 and the first mixture into oil-in-water microspheres by microfluidics technology and dropping the microspheres into a calcium chloride solution to form light yellow sunscreen microspheres; Step 4: adding sodium carbomer into water to form a gel, then adding a water-soluble organic sunscreen, and adding a pH adjuster while heating to dissolve until the solution is transparent, to obtain a second mixture; Step 5: Add the active substance to the second mixture obtained in step 4, and stir continuously until the mixture is uniform to obtain a third mixture; Step 6: adding a thickener to the third mixture obtained in step 5 to prepare a hydrogel; Step 7: Add the sunscreen microbeads obtained in step 3 into the hydrogel to obtain a dispersion system containing all types of sunscreen microbeads.

2. The method for preparing a hydrogel containing all types of sunscreen microbeads according to claim 1, characterized in that: The composition and ratio of the oil-soluble organic sunscreen in step 1 are: ethylhexyl methoxycinnamate: ethylhexyl salicylate: octocrylene: diethylaminohydroxybenzoyl hexyl benzoate: bis-ethylhexyloxyphenol methoxyphenyl triazine = 5-10: 1-5: 4-10: 1-5: 1-5; the heating temperature in step 1 is 60-80°C.

3. The method for preparing a hydrogel containing all types of sunscreen microbeads according to claim 1, characterized in that: The mass concentrations of the sodium alginate solution and the PVA solution in step 2 are both 1%-3%; the mass ratio of the sodium alginate solution to the PVA solution is 1-5:1; Zinc oxide and titanium dioxide each account for 3%-5% of the total solution mass.

4. The method for preparing a hydrogel containing all types of sunscreen microbeads according to claim 1, characterized in that: In step 3, the pushing speed of the sunscreen oil is 0.1-0.25 mL / min, the pushing speed of the first mixture is 0.3-0.8 mL / min, and the flow rate ratio is 1:2-5; the mass concentration of the calcium chloride solution is 5%-10%.

5. The method for preparing a hydrogel containing all types of sunscreen microbeads according to claim 1, characterized in that: The mass concentration of sodium carbomer in the gel in step 4 is 0.5-1%; the composition and ratio of the water-soluble organic sunscreen are: phenylbenzimidazole sulfonic acid: disodium phenyl dibenzimidazole tetrasulfonate = 5:8-10; the mass ratio of sodium carbomer to the water-soluble organic sunscreen is 1:10-36; the heating temperature is 70-90°C; and the pH adjuster is triethanolamine or sodium hydroxide.

6. The method for preparing a hydrogel containing all types of sunscreen microbeads according to claim 1, characterized in that: In step 5, the active substance is extracts of Dendrobium officinale, chamomile, calendula or carbon dots, and the mass concentration of the active substance in the third mixture is 0.1%-1%.

7. The method for preparing a hydrogel containing all types of sunscreen microbeads according to claim 1, characterized in that: The thickeners in step 6 are xanthan gum and hydroxyethyl cellulose, and the amount of the thickener added is 0.1%-0.5% of the mass of the third mixture, wherein xanthan gum accounts for 1-2 parts and hydroxyethyl cellulose accounts for 1-3 parts.

8. The method for preparing a hydrogel containing all types of sunscreen microbeads according to claim 1, characterized in that: In step 7, the mass ratio of the light yellow sunscreen microbeads to the hydrogel is 1:2-10.

9. A hydrogel containing all types of sunscreen microbeads obtained by the method for preparing a hydrogel containing all types of sunscreen microbeads as described in any one of claims 1 to 8.

10. The method for preparing a hydrogel containing all types of sunscreen microbeads according to any one of claims 1 to 8, wherein the hydrogel containing all types of sunscreen microbeads is used for preparing sunscreen products.

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