Radiation refrigeration sunscreen cream with broad-spectrum sunscreen function as well as preparation method and application of radiation refrigeration sunscreen cream

Abstract

The invention belongs to the field of preparation of daily necessities, and particularly relates to radiation refrigeration sunscreen cream with a broad-spectrum sunscreen function as well as a preparation method and application of the radiation refrigeration sunscreen cream. The ZnO-coated ZIF-8 composite material is prepared by simply mixing raw materials in an organic solvent environment, and the sunscreen cream disclosed by the invention comprises the following components in percentage by weight: 10-15wt% of ZnO-coated ZIF-8 composite material, 10-15wt% of zinc oxide-coated ZIF-8 composite material, 10-15wt% of zinc oxide-coated ZIF-8 composite material and the balance of water. The ZnO (at) ZIF-8 composite material is obtained by reacting zinc oxide nanoparticles with 2-methylimidazole in an organic solvent. The sunscreen cream product has high sunlight reflectivity and high ultraviolet protection effect at the same time. The sunscreen cream can be applied under direct sunlight in an actual scene to realize an effective cooling effect, and has a high SPF value, broad-spectrum sunscreen capability covering UVA and UVB, and good waterproof performance.

Description

Technical Field

[0001] The invention belongs to the field of daily necessities preparation, and particularly relates to a radiation cooling sunscreen with broad-spectrum sun protection function, and a preparation method and application thereof. Background Art

[0002] Global warming and energy shortages have become two major challenges facing people worldwide. To meet cooling needs in daily life and production, air conditioning and other cooling methods have become widely used. However, these cooling devices, which rely on external energy input, consume large amounts of electricity and emit greenhouse gases, further exacerbating global warming. Faced with enormous environmental and energy pressures, people need to explore new, green cooling methods.

[0003] Radiative cooling technology has garnered widespread attention in recent years due to its ability to dissipate heat completely autonomously, requiring no external energy input. Achieving this radiative cooling effect requires materials with two properties: high reflectivity within the 0.3-2.5μm range of the solar spectrum to prevent absorption of solar thermal radiation; and high emissivity within the 8-13μm atmospheric window, which achieves cooling by radiating its own heat as electromagnetic waves into outer space, where the temperature is only 3K. In recent years, with the continuous advancement of research, a variety of radiative cooling materials have emerged, covering a wide range of materials and applications, with promising applications in architectural coatings, refrigerated transportation, and personal thermal management.

[0004] Personal thermal management is closely related to human life. Good thermal management not only provides comfort but also prevents the harmful effects of high temperatures on the human body, making it of great research and application value. However, current research focuses almost entirely on the manufacture of radiative cooling clothing, with little research on other daily necessities.

[0005] Long-term exposure to ultraviolet rays is a major cause of skin cancer. Sunscreen can be applied to the skin surface and provides protection from ultraviolet rays through physical scattering and chemical absorption of its active ingredients. Ultraviolet rays are divided into UVA (long wave) and UVB (medium wave). UVB acts on the surface of the skin and is the main cause of sunburn and cell cancer; UVA can penetrate the epidermis and directly damage the dermis, accelerating skin aging while also increasing the risk of skin cancer. This shows that an ideal sunscreen should provide effective protection against both UVA and UVB. As a cosmetic widely used in daily life, sunscreen has a high degree of overlap with radiant cooling in its usage scenarios. By integrating radiant cooling with sun protection, a new type of sunscreen product is created that has great application value.

[0006] Traditional radiative cooling materials include white paint, inorganic material film and polymer film, etc. They use the high refractive index and wide infrared emissivity of inorganic microparticles (such as titanium dioxide) and the excellent infrared emissivity of specific polymers (such as polyvinyl fluoride) to achieve the cooling effect, and some studies further improve the radiative cooling performance by combining the advantages of the two materials. The cost of such materials is relatively controllable, and the application scenarios are relatively wide, but the research on personal thermal management is almost entirely focused on radiative cooling clothing, and there is almost no report on cosmetics.

[0007] As a radiative cooling material designed and simulated, photonic devices often have advantages in solar reflectivity and infrared emissivity compared to traditional radiative cooling materials, but the high cost of design and manufacturing greatly limits their widespread application, and the delicate and fragile nanostructure also makes it difficult to be used for personal thermal management.

[0008] At present, the shortcomings in the prior art are as follows:

[0009] 1. Traditional radiative cooling materials are abundant in sources, widely used in various application scenarios, low in cost, and easy to mass-produce, but the research on personal thermal management is focused on the field of textiles and clothing, and almost no research is conducted in the field of daily chemicals.

[0010] 2. Photonic devices have exquisite structure and can achieve extremely high solar reflectivity and infrared emissivity, but the cost of design and preparation is extremely high, and they cannot be applied to personal thermal management.

[0011] 3. Current sunscreen products focus on protecting against ultraviolet rays and lack effective protection against solar heat radiation. People are still at risk of various heat-related diseases such as heat stroke and heat exhaustion caused by heat stress under long-term exposure to sunlight. SUMMARY

[0012] To solve the above technical problems, the present application provides the following technical solutions:

[0013] The present application provides a radiative cooling sunscreen with broad-spectrum sunscreen function, which comprises 10-15wt% of ZnO@ZIF-8 composite material; the ZnO@ZIF-8 composite material is obtained by reacting zinc oxide nanoparticles and 2-methyl imidazole in an organic solvent.

[0014] Preferably, the molar ratio of the zinc oxide nanoparticles and 2-methyl imidazole is 1:8-10.

[0015] Preferably, the radiative cooling sunscreen with broad-spectrum sunscreen function further comprises 10-15wt% of titanium dioxide; the particle size of the titanium dioxide is 1-3μm.

[0016] Preferably, the radiation refrigeration sunscreen cream with broad-spectrum sunscreen function further comprises a viscosity regulator, a formula stabilizer and a skin cream.

[0017] Further, the viscosity regulator is selected from ethanol, and the formula stabilizer is selected from liquid paraffin, decamethylcyclopentasiloxane and glycerol; the mass ratio of the decamethylcyclopentasiloxane, glycerol, ethanol, liquid paraffin and skin cream is 8-12:8-12:8-12:18-22:23-27.

[0018] Preferably, the organic solvent is selected from ethanol, methanol or N,N-dimethylformamide.

[0019] Further, the organic solvent used in the synthesis can also be selected from methanol, DMF and the like, but for safety considerations, ethanol is used as a non-toxic preparation solvent in the present application.

[0020] Preferably, the temperature of the reaction is room temperature (25±5℃), and the reaction time is 12-48h.

[0021] Preferably, the mixture obtained after the reaction is washed with ethanol and dried at 55-65℃ for 9-12h.

[0022] The present application also provides a preparation method of the radiation refrigeration sunscreen cream with broad-spectrum sunscreen function as described above, comprising the following steps:

[0023] S11: preparing an ethanol suspension of zinc oxide nanoparticles and an ethanol solution of 2-methylimidazole, respectively;

[0024] S12: adding the ethanol suspension of zinc oxide nanoparticles into the ethanol solution of 2-methylimidazole, and reacting at room temperature for 12-48h to obtain a mixture;

[0025] S13: solid-liquid separation is performed on the mixture obtained in step S12, the solid is washed with ethanol for multiple times, and then dried at 55-65℃ for 9-12h to obtain a ZnO@ZIF-8 composite material;

[0026] S14: mixing the ZnO@ZIF-8 composite material, titanium dioxide, viscosity regulator, formula stabilizer and skin cream at room temperature for 12-24h to obtain the radiation refrigeration sunscreen cream with broad-spectrum sunscreen function.

[0027] Specifically, the preparation method of the ZnO@ZIF-8 composite material comprises the following steps:

[0028] The preparation of the composite material ZnO@ZIF-8 composite material required by the present application comprises the following steps: synthesis by an organic solvent method, mixing ZnO and 2-methylimidazole in ethanol, and synthesizing ZnO@ZIF-8 composite material by 2-methylimidazole and Zn 2+The ZnO@ZIF-8 composite material was prepared by in situ growth of a ZIF-8 shell directly on the ZnO surface, wherein the molar ratio of ZnO to 2-methylimidazole was 1:8-1:10.

[0029] The weighed ZnO nanoparticles were added to 15 mL of ethanol and placed in an ultrasonic cleaner for thorough dispersion. The weighed 2-methylimidazole was dissolved in 35 mL of ethanol, and the dispersed ZnO suspension was then added dropwise to the latter while stirring vigorously. After reacting at room temperature for 12-48 hours, the precipitate was collected, washed with anhydrous ethanol and centrifuged (8000 rpm) three times, and dried in an oven at 60°C for 9-12 hours. The dried product was ground in a mortar and the resulting white powder was collected for later use.

[0030] Specifically, step S14 comprises mixing the following ingredients to prepare a sunscreen: 10-15 wt% ZnO@ZIF-8; 10-15 wt% TiO2, particle size 1-3 μm; 10 wt% decamethylcyclopentasiloxane; 10 wt% glycerin; 10 wt% ethanol; 20 wt% liquid paraffin; and 25 wt% of a commercial moisturizer without radiant cooling / sunscreen functions. The ingredients are added to a reaction vessel and stirred at room temperature for 12-24 hours to produce a radiant cooling sunscreen product with broad-spectrum sunscreen functions.

[0031] The efficacy of each ingredient is as follows: ZnO@ZIF-8 serves as a broad-spectrum sunscreen in the UVA / UVB band (290-400nm), the main component of solar reflection in the visible light band (400-780nm), and an auxiliary component of emission in the mid-infrared band (8-13μm); TiO2 serves as a sunscreen in the UVB band (290-320nm), the main component of solar reflection in the near-infrared band (0.78-2.5μm), and an auxiliary component of emission in the mid-infrared band (8-13μm); decamethylcyclopentasiloxane and glycerin serve as the main components of emission in the mid-infrared band and also as formula stabilizers; liquid paraffin serves as a formula stabilizer, forming a stable emulsion with TiO2 particles and ZnO@ZIF-8 composite materials; ethanol serves as a formula viscosity regulator; and commercial moisturizer is used to imitate the appearance of commercially available cosmetics and enhance product texture.

[0032] The ZnO@ZIF-8 composite material, prepared by simply mixing raw materials in an ethanol environment, has both high sunlight reflectivity (especially in the visible light wavelength range) and high UV protection.

[0033] The present invention also provides use of the radiation cooling sunscreen with broad-spectrum sun protection function in the preparation of personal thermal management cosmetics.

[0034] The present invention also provides an application of the above-mentioned sunscreen in actual scenarios: the sunscreen can achieve an effective cooling effect under direct sunlight, and at the same time has a high SPF value, a broad-spectrum sun protection ability covering UVA and UVB, and good waterproof performance.

[0035] The technical solution of the present invention has the following advantages over the prior art:

[0036] (1) The present invention synthesizes a composite material ZnO@ZIF-8 in a safe and non-toxic ethanol solvent. The material has high sunlight reflectivity while effectively providing broad-spectrum UV protection.

[0037] (2) The present invention proposes and prepares a radiant heat dissipation sunscreen with broad-spectrum sun protection ability. The sunscreen has broad-spectrum sun protection function, high sunlight reflectivity and high and medium infrared emissivity, and can achieve effective sun protection and radiant cooling effects under high temperatures outdoors. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is an electronic photo of the sunscreen prepared in Example 1.

[0039] Figure 2 This is the sample morphology of the ZnO@ZIF-8 material in Example 1 under a scanning electron microscope.

[0040] Figure 3 The sample morphology of the ZnO@ZIF-8 material in Example 1 under a transmission electron microscope; wherein, a is a transmission electron microscope photograph of the sample in Example 1, b is a scanning transmission electron microscope high-angle annular dark field photograph of the sample in Example 1, and c to e are element distribution diagrams of oxygen, carbon, and zinc, respectively.

[0041] Figure 4 Fourier transform infrared spectra of the ZnO nanoparticle raw material used in Comparative Example 1, the ZIF-8 material prepared in Comparative Example 2, and the ZnO@ZIF-8 material synthesized in Example 1.

[0042] Figure 5 These are the X-ray diffraction test patterns of the ZnO nanoparticle raw material used in Comparative Example 1, the ZIF-8 material prepared in Comparative Example 2, and the ZnO@ZIF-8 material synthesized in Example 1.

[0043] Figure 6 These are the reflectivity and emissivity data of the sunscreen prepared in Example 1.

[0044] Figure 7 The graph shows the UV transmittance test results of Example 1 and Comparative Example 4.

[0045] Figure 8The figure shows the sun protection factor (SPF) values ​​of Example 1 and Comparative Example 4.

[0046] Figure 9 Schematic diagram of the cross section of the experimental device in Test Example 6.

[0047] Figure 10 This is a test chart of the actual outdoor cooling effect of Example 1 and Comparative Example 4. DETAILED DESCRIPTION

[0048] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0049] Example 1:

[0050] This embodiment provides a method for directly synthesizing a ZnO@ZIF-8 composite material in an ethanol solvent, and the steps are as follows:

[0051] Step 1: Raw material pretreatment:

[0052] Weighed ZnO nanoparticles were prepared into a ZnO ethanol suspension, and 2-methylimidazole was dissolved in ethanol;

[0053] Specifically, prepare 0.3g of ZnO nanoparticles, 2.5g of 2-methylimidazole, and 50mL of ethanol. At room temperature, add the weighed ZnO nanoparticles to 25mL of ethanol and fully disperse them in a cell disruptor for 20 minutes to obtain a ZnO ethanol suspension. At room temperature, add the weighed 2-methylimidazole to 25mL of ethanol and stir to completely dissolve it.

[0054] Step 2: In situ synthesis of ZnO@ZIF-8 on the surface of ZnO nanoparticles: adding the ZnO ethanol suspension prepared in step 1 dropwise to the ethanol solution of 2-methylimidazole prepared in step 1, reacting under vigorous stirring at room temperature to in situ grow a ZIF-8 layer on the surface of the ZnO nanoparticles;

[0055] Specifically, the ethanol suspension of ZnO dispersed in step 1 was added dropwise to the ethanol solution of 2-methylimidazole in step 1 at room temperature at a rate of 1 drop / second. The suspension was added dropwise over 10 minutes, and then reacted for 48 hours under vigorous stirring. After the reaction was completed, the resulting white precipitate was collected by centrifugation at 8000 rpm for 5 minutes, washed three times with ethanol, and then dried in an oven at 65°C for 12 hours to obtain the ZnO@ZIF-8 composite material.

[0056] This embodiment provides a radiant heat dissipation sunscreen with broad-spectrum sun protection function, the components of which are: 10g of ZnO@ZIF-8 composite material, 15g of TiO2 particles, 10g of decamethylcyclopentasiloxane, 10g of glycerin, 10g of ethanol, 20g of liquid paraffin, and 25g of Nivea brand commercially available moisturizer that does not have sun protection or radiant cooling capabilities.

[0057] The particle size of ZnO@ZIF-8 synthesized in this embodiment is 0.22-0.6 μm, and the average particle size of TiO2 particles is 1-3 μm. The components are mixed in a container at room temperature and stirred for 24 hours to obtain a radiant heat dissipation sunscreen with broad-spectrum sun protection function. The electronic photo of the sunscreen is shown in FIG. Figure 1 shown.

[0058] Example 2:

[0059] The method of this embodiment is the same as that of Example 1, except that the mass of the ZnO@ZIF-8 material in the sunscreen formula is 15 g, the mass component of TiO2 is 10 g, and the other experimental steps and experimental parameters are consistent with those of Example 1.

[0060] Example 3:

[0061] The method of this embodiment is the same as that of Example 1, except that the reaction time for synthesizing the ZnO@ZIF-8 material in step 2 is 6 h, and the other experimental steps and experimental parameters are consistent with those of Example 1.

[0062] Comparative Example 1:

[0063] The method of this comparative example is the same as that of Example 1, except that the ZnO@ZIF-8 composite material is replaced by ZnO nanoparticles in the sunscreen formula, and the other experimental steps and experimental parameters are consistent with those of Example 1.

[0064] Comparative Example 2:

[0065] The method of this comparative example is the same as that of Example 1, except that the ZnO@ZIF-8 composite material is replaced with ZIF-8 in the sunscreen formula. The other experimental steps and experimental parameters are consistent with those of Example 1, wherein the steps for preparing the ZIF-8 material are as follows:

[0066] In step 1, 1.8 g of zinc nitrate hexahydrate and 4.1 g of 2-methylimidazole were added to 40 g of methanol and shaken in an ultrasonic bath to ensure complete dissolution. In step 2, the two solutions were mixed and reacted with vigorous stirring for 24 hours. After the reaction was complete, the resulting white precipitate was collected by centrifugation at 8000 rpm for 5 minutes, washed three times with methanol, and then dried in an oven at 65°C for 12 hours to obtain the ZIF-8 material.

[0067] Comparative Example 3:

[0068] The comparative example is the same as the method of Example 1, except that the ZnO@ZIF-8 composite material is not added in the sunscreen cream formula, and other experimental steps and experimental parameters are consistent with Example 1.

[0069] Comparative Example 4:

[0070] A sample of a commercially available sunscreen cream (L'Oreal Men's Multi-Defense Moisturizing Lotion) with a nominal SPF 50+, which mainly contains effective sunscreen ingredients: homosalate, octocrylene, ethylhexyl salicylate, Dibenzoylmethane, and the rest are additives and necessary ingredients.

[0071] Test Example 1:

[0072] (I) Based on Example 1, the morphology of ZnO nanoparticle raw material and synthesized ZnO@ZIF-8 material was observed, and the sample morphology under scanning electron microscope is shown in Figure 2 It can be seen that the ZnO raw material presents an amorphous structure, and the average particle size is about 180 nm, while the ZnO@ZIF-8 composite material presents a clear cubic structure, and the average particle size is about 380 nm; further, as shown in Figure 3 The morphology of ZnO@ZIF-8 composite material was observed by transmission electron microscope, and the material presents a clear core-shell structure under transmission electron microscope, the dark ZnO core is wrapped by the light-colored ZIF-8 shell, and the shell presents a clear dodecahedron structure. In the subsequent TEM mapping test, only the C element existing in ZIF-8 is enriched in the shell of the composite material, and only the O element existing in ZnO is gathered in the core of the composite material, which further proves the successful synthesis of ZnO@ZIF-8 material.

[0073] (II) Based on Example 1, Fourier transform infrared spectroscopy analysis was performed on ZnO nanoparticle raw material, ZIF-8 material and synthesized ZnO@ZIF-8 material, and the results are shown in Figure 4 From the figure, it can be seen that the ZnO@ZIF-8 composite material shows C=N and C=C stretching vibration peaks of imidazole ring at 1581 cm -1 and 1439 cm -1 , shows C-N bond stretching vibration peak of imidazole ring at 1309 cm -1 , shows in-plane bending vibration peak of imidazole ring at 1146 cm -1 , shows out-of-plane bending vibration of imidazole ring at 757 cm -1 , and shows ring out-of-plane bending vibration of imidazole ring at 531 cm -1The characteristic peaks of ZnO appeared, which proved that ZIF-8 and ZnO coexisted in the system; in addition, X-ray diffraction tests were also performed on the three, and the results are shown in Figure 5 Fig. 2, the signal peaks of the ZnO@ZIF-8 composite material correspond to the standard peaks of ZnO and ZIF-8, which further proves the successful synthesis of the ZnO@ZIF-8 composite material.

[0074] The reflectivity of the samples in the above examples and comparative examples in the wavelength range of 300-2500 nm and the emissivity in the range of 8-13 μm were tested, and the experimental results are shown in Table 1, wherein the reflectivity and emissivity data of Example 1 are shown in Figure 6

[0075] Table 1 Reflectivity and emissivity test of each example and comparative example

[0076]

[0077] Analysis of experimental results: From the experimental results in Table 1, it can be seen that the radiation cooling sunscreen cream prepared in the examples of the present application has a high reflectivity in the wavelength range of 300-2500 nm and a high emissivity in the wavelength range of 8-13 μm, with the highest being 90.99% and 90.61%, respectively. It is proved that the combination of ZnO and the ZIF-8 shell grown outside it improves the reflectivity of the product.

[0078] Test Example 3

[0079] The ultraviolet transmittance of the samples in the above examples and comparative examples in the range of 290-400 nm was tested, and the SPF value was calculated, and the experimental results are shown in Table 2, wherein the ultraviolet transmittance test results of Example 1 and Comparative Example 4 are shown in Figure 7

[0080] Table 2 Test results of SPF value of each example and comparative example

[0081] serial number SPF value Example 1 55.22 Example 2 55.36 Example 3 52.18 Comparative Example 1 52.99 Comparative Example 2 27.22 Comparative Example 3 14.60 Comparative Example 4 53.69

[0082] Analysis of experimental results: From the experimental results in Table 2, it can be seen that the radiation cooling sunscreen cream prepared in the examples of the present application has good sunscreen ability, with the highest SPF value being 55.36, and the ZIF-8 shell grown outside the ZnO does not affect its ultraviolet absorption capacity.

[0083] Test Example 4

[0084] The absorbance of Example 1 and Comparative Example 4 in the range of 290-400 nm was tested, and the critical wavelength of the two was calculated, and the experimental results are shown in Table 3.

[0085] Table 3 Critical wavelength of Example 1 and Comparative Example 4​​

[0086] serial number Critical wavelength (nm) Example 1 386 Comparative Example 4 375

[0087] Analysis of experimental results: From the experimental results in Table 3, it can be seen that the radiant cooling sunscreen prepared in Example 1 of the present invention has good broad-spectrum sun protection ability, and the critical wavelength reaches 386nm, which indicates that it has excellent sun protection performance in both UVA and UVB wavelength ranges.

[0088] Test Example 5:

[0089] The waterproof performance of Example 1 and Comparative Example 4 was tested. Specifically, equal amounts of Example 1 and Comparative Example 4 were applied to the same substrate, the substrate was immersed in water and gently shaken for 20 minutes, then taken out and allowed to stand for 20 minutes, the immersion drying process was repeated 2 times (equivalent to 40 minutes) or 4 times (equivalent to 80 minutes), and then taken out and dried. The SPF values ​​of the two were tested. The results are shown in the figure. Figure 8 As shown in Table 4.

[0090] Table 4 SPF test results of Example 1 and Comparative Example 4

[0091] serial number SPF after 40 minutes test SPF after 80min test Example 1 55.12 42.92 Comparative Example 4 43.65 28.73

[0092] Analysis of experimental results: From the experimental results in Table 4, it can be seen that the radiant cooling sunscreen prepared in Example 1 of the present invention has good water resistance. The results of the 40-minute water resistance test and the 80-minute water resistance test are significantly better than those of commercially available sunscreens. After the 80-minute test, the SPF value of 42.92 is maintained, and it still has effective sun protection ability.

[0093] Test Example 6:

[0094] The actual outdoor cooling effect of Example 1 and Comparative Example 4 was tested. The specific experimental method was as follows: a foam plastic box with good thermal insulation effect was prepared, and its surface was covered with aluminum foil to further improve the thermal insulation effect. Each experimental sample was evenly applied to the bottom of the box, and a thermocouple was connected to monitor the temperature in real time. The upper surface of the box was covered with polyethylene film to isolate the influence of heat convection on the experimental results. The experiment was carried out on a hot summer day in a mostly sunny day. The thermocouple recorded the temperature change curves of Example 1, the comparative example and the blank sample respectively. The cross-sectional schematic diagram of the experimental apparatus is shown in FIG. Figure 9 The experimental results are shown in Figure 10 , the average temperature is shown in Table 5:

[0095] Table 5 Average temperature of Examples and Comparative Examples

[0096] serial number Average temperature (℃) Example 1 60.72 Comparative Example 1 61.98 Comparative Example 2 63.00 Comparative Example 3 63.51 Comparative Example 4 64.97 blank 65.02

[0097] Experimental results analysis: From Table 5 and Figure 10It can be seen from the experimental results that the radiant cooling sunscreen prepared in Example 1 of the present invention has a good actual cooling ability and can achieve an average cooling effect of 4.25°C in a hot environment.

[0098] Effect evaluation:

[0099] The present invention proposes and prepares a composite material, ZnO@ZIF-8, that has both radiative cooling and UV protection capabilities. This material effectively reflects sunlight (especially within the visible light range) while retaining the broad-spectrum UV protection capabilities of ZnO. Secondly, the present invention proposes and formulates a sunscreen with radiative cooling capabilities. This sunscreen has a high SPF value, broad-spectrum sun protection, good water resistance, and can achieve effective cooling in outdoor tests. At the same time, through the complementary and synergistic effects between the ingredients, the radiative cooling function and the broad-spectrum UV protection function are integrated into cosmetics, providing new ideas for future research on radiative cooling in the direction of personal thermal management.

[0100] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A radiant cooling sunscreen with broad-spectrum sun protection function, characterized in that: Calculated by weight, the ZnO@ZIF-8 composite material comprises 10-15 wt % of the ZnO@ZIF-8 composite material; the ZnO@ZIF-8 composite material is obtained by reacting zinc oxide nanoparticles and 2-methylimidazole in an organic solvent.

2. The radiant cooling sunscreen with broad-spectrum sun protection function according to claim 1, characterized in that: The molar ratio of the zinc oxide nanoparticles to 2-methylimidazole is 1:8-10.

3. The radiant cooling sunscreen with broad-spectrum sun protection function according to claim 1, characterized in that: Calculated by weight, the radiation cooling sunscreen with broad-spectrum sun protection function further comprises 10-15wt% of titanium dioxide; the particle size of the titanium dioxide is 1-3μm.

4. The radiant cooling sunscreen with broad-spectrum sun protection function according to claim 1, characterized in that: The radiation cooling sunscreen with broad-spectrum sun protection function further comprises a viscosity regulator, a formula stabilizer and a moisturizer.

5. The radiant cooling sunscreen with broad-spectrum sun protection function as claimed in claim 4, characterized in that: The viscosity regulator is selected from ethanol, and the formula stabilizer is selected from liquid paraffin, decamethylcyclopentasiloxane and glycerin; the mass ratio of decamethylcyclopentasiloxane, glycerin, ethanol, liquid paraffin and moisturizer is 8-12:8-12:8-12:18-22:23-27.

6. The radiant cooling sunscreen with broad-spectrum sun protection function according to claim 1, characterized in that: The organic solvent is selected from ethanol, methanol or N,N-dimethylformamide.

7. The radiant cooling sunscreen with broad-spectrum sun protection function according to claim 1, characterized in that: The reaction temperature is room temperature, and the reaction time is 12-48 hours.

8. The radiant cooling sunscreen with broad-spectrum sun protection function according to claim 1, characterized in that: After the reaction, the mixture was washed with ethanol and dried at 55-65° C. for 9-12 h.

9. A method for preparing the radiant cooling sunscreen with broad-spectrum sun protection function according to any one of claims 1 to 8, characterized in that: The steps include: S11: preparing an ethanol suspension of zinc oxide nanoparticles and an ethanol solution of 2-methylimidazole respectively; S12: adding the ethanol suspension of the zinc oxide nanoparticles to the ethanol solution of 2-methylimidazole, and reacting at room temperature for 12-48 hours to obtain a mixture; S13: performing solid-liquid separation on the mixture obtained in step S12, washing the solid with ethanol for multiple times, and then drying at 55-65° C. for 9-12 hours to obtain a ZnO@ZIF-8 composite material; S14: Mixing the ZnO@ZIF-8 composite material, titanium dioxide, a viscosity modifier, a formula stabilizer, and a moisturizer at room temperature for 12-24 hours to obtain the radiation cooling sunscreen with broad-spectrum sun protection function.

10. Use of the radiant cooling sunscreen with broad-spectrum sun protection function according to any one of claims 1 to 8 in the preparation of personal thermal management cosmetics.

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