Composite sun-screening agent containing natural polyphenol and preparation method thereof

Abstract

The invention discloses a composite sun-screening agent containing natural polyphenol, the composite sun-screening agent comprises a polyphosphazene shell layer and an inner core, the raw materials of the polyphosphazene shell layer comprise phosphonitrilic chloride trimer and a natural polyphenol compound, and the inner core is modified titanium dioxide; the invention also discloses a preparation method of the natural polyphenol-containing composite sun-screening agent. The method comprises the following steps: step 1, dispersing the modified titanium dioxide powder and the polyphosphazene shell material under ultrasonic stirring; 2, adding an organic alkali under an ultrasonic stirring condition for reaction; and step 3, sequentially centrifuging, washing and drying to obtain the composite sun-screening agent. According to the composite sun-screening agent, the structure that the modified titanium dioxide core is wrapped by the polyphosphazene shell layer is adopted, harm caused by direct contact between titanium dioxide and skin is avoided, natural polyphenol compounds are added into the polyphosphazene shell layer, free radicals are removed, accelerated skin aging is prevented, the sun-screening effect of the composite sun-screening agent is enhanced, and the sun-screening effect of the composite sun-screening agent is improved. The invention is applicable to the technical field of skin protection.

Description

Technical Field

[0001] The present invention belongs to the technical field of skin protection, and in particular relates to a composite sunscreen containing natural polyphenols and a preparation method thereof. Background Art

[0002] Solar ultraviolet radiation is divided into three categories according to wavelength, including UVA (400nm - 315nm), UVB (315nm - 280nm) and UVC (280nm - 100nm). UVC is completely reduced and dispersed through the ozone-oxygen cycle, and the remaining UVA and part of UVB reach the earth's surface. High doses of solar ultraviolet rays are harmful to the human body and can cause erythema, premature skin aging and skin cancer. To counteract these adverse effects, using sunscreen products is a common skin protection measure.

[0003] Physical sunscreens titanium dioxide nanoparticles and zinc oxide nanoparticles have excellent ultraviolet absorption effects and are widely used in sunscreens. However, they can generate strongly oxidizing free radicals under ultraviolet irradiation, leading to skin aging; on the other hand, the high surface energy of nanoparticles and easy aggregation can result in a heavy skin feel for consumers when the added content is high. By performing surface coating treatment on titanium dioxide and zinc oxide nanoparticles, the above adverse factors can be effectively inhibited.

[0004] Natural polyphenolic compounds are a class of secondary metabolites widely present in plants, and mainly have antioxidant, whitening, anti-inflammatory, antibacterial and other effects in cosmetics. Since natural polyphenolic compounds have a special conjugated structure that can absorb ultraviolet rays, plant extracts rich in natural polyphenols, such as pomegranate peel extract, grapefruit seed extract, etc., are often added to sunscreens. The polyphenol components in these extracts can effectively absorb UVB and UVA, providing broad-spectrum sun protection for the skin.

[0005] Currently, there are mainly two application methods of natural polyphenolic compounds in sunscreens: one is to mix the extracted natural polyphenol components with other components of cosmetics to improve the sun protection effect or replace some chemical components to improve the adaptability of the population; the other is to macromolecularize natural polyphenol small molecules to prepare nanomaterials with sun protection effects. For example, the Chinese invention patent "A Whitening Sunscreen Eye Cream Containing Plant Extracts and Its Preparation Method" (application number 202410520921.4) mixes various active ingredients such as resveratrol, Scutellaria baicalensis root extract, and Centella asiatica extract in proportion and mixes them with other thickening agents and other components to prepare an eye cream to improve the protection and repair effects of the eye cream against ultraviolet irradiation. The Chinese invention patent "A Poly-Natural Polyphenol Type Sunscreen Gel and Its Preparation Method" (application number 202010537797.4) macromolecularizes the natural polyphenol small molecule caffeic acid phenethyl ester to prepare nanomaterials and mixes them with a gel substrate to prepare a sunscreen gel. Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies in the above-mentioned prior art and provide a composite sunscreen containing natural polyphenols. The composite sunscreen adopts a structure in which a polyphosphazene shell wraps and modifies a titanium dioxide core, avoiding direct contact between titanium dioxide and the skin to cause harm. By adding natural polyphenolic compounds to the polyphosphazene shell, it can scavenge free radicals generated by the photocatalysis of titanium dioxide and free radicals generated during the metabolism of human cells, preventing free radicals from accelerating skin aging. At the same time, natural polyphenolic compounds also have the function of absorbing ultraviolet light, improving the sunscreen effect of the composite sunscreen.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a composite sunscreen containing natural polyphenols, characterized in that it includes a polyphosphazene shell and a core, the raw materials of the polyphosphazene shell include hexachlorocyclotriphosphazene and natural polyphenolic compounds, and the core is modified titanium dioxide.

[0008] The above-mentioned composite sunscreen containing natural polyphenols is characterized in that the raw materials of the polyphosphazene shell further include nano-silica, and the mass of the nano-silica is not greater than 5% of the total mass of the raw materials of the polyphosphazene shell.

[0009] By adding nano-silica to the polyphosphazene shell in the present invention, it can reflect a part of ultraviolet light, reduce the ultraviolet light reaching the surface of the modified titanium dioxide, and further reduce the free radicals generated by the photocatalytic action of titanium dioxide.

[0010] The above-mentioned composite sunscreen containing natural polyphenols is characterized in that the natural polyphenolic compound is one of resveratrol, curcumin, catechins, tea polyphenols, phloretin, magnolol, hesperetin, ellagic acid, gallic acid, tannic acid, coenzyme panthenol, flavonoids, flavanols, dihydroflavonoids and isoflavonoids, and the mass of the natural polyphenolic compound accounts for 20% - 80% of the total mass of the raw materials of the polyphosphazene shell.

[0011] In addition, the present invention also discloses a preparation method of the above-mentioned composite sunscreen containing natural polyphenols, characterized in that the preparation method includes the following steps:

[0012] Step 1: Disperse the modified titanium dioxide powder, hexachlorocyclotriphosphazene and natural polyphenolic compounds in an organic solvent under ultrasonic stirring to obtain a dispersion;

[0013] Step 2: Add an organic base to the dispersion obtained in Step 1 under ultrasonic stirring to carry out a first polymerization reaction to obtain a mixed solution;

[0014] Step 3: Centrifuge the solid product of the mixed solution obtained in Step 2, and then wash and dry it in sequence to obtain the composite sunscreen.

[0015] By coating the surface of modified titanium dioxide with a polyphosphazene shell layer, a three-layer protection structure of polyphosphazene, modified titanium dioxide, and polyphosphazene is formed, effectively improving the sun protection effect of the composite sunscreen agent.

[0016] The preparation method of a composite sunscreen agent containing natural polyphenols as described above is characterized in that the preparation method of the modified titanium dioxide powder in step one includes the following steps:

[0017] Step 101: Pour titanium dioxide into a sodium hydroxide solution and stir, followed by ultrasonic and hydrothermal reactions to obtain a mixed solution;

[0018] Step 102: Wash and centrifuge the mixed solution obtained in step 101, then soak it in a hydrochloric acid solution, and then wash, centrifuge, dry, and grind it to obtain a powder;

[0019] Step 103: Spread the powder obtained in step 102 between two ceramic plates, use ultrasonic waves to disperse the powder particles, and then place it in an inert gas environment for calcination. After grinding, modified titanium dioxide powder is obtained.

[0020] In the present invention, titanium dioxide is treated with a sodium hydroxide solution to increase the surface roughness of titanium dioxide, thereby enhancing the absorption rate of titanium dioxide for ultraviolet light; in step 103, the ultrasonic waves are used to weaken the force between the powder particles and disperse the powder particles. At the same time, by spreading the powder between two ceramic plates, the gravity of the upper ceramic plate and the frictional force between the powder and the ceramic plate are utilized to keep the powder particles dispersed by ultrasonic waves still in a dispersed state after turning off the ultrasonic waves, preventing sintering between a large number of powder particles during the calcination process and ensuring the particle size of the powder particles; then, a small part of the sintered powder particles after calcination are dispersed by grinding.

[0021] The preparation method of a composite sunscreen agent containing natural polyphenols as described above is characterized in that a copper salt or an iron salt is added during the stirring process in step 101. The copper salt is one of copper chloride, copper sulfate, copper carbonate, and copper acetate, and the iron salt is one of ferric chloride, ferric sulfate, and ferric acetate. The concentration of the sodium hydroxide solution is 0.5 mol / L to 5 mol / L, the temperature of the hydrothermal reaction is 150 °C to 180 °C, and the duration of the hydrothermal reaction is 20 h to 24 h.

[0022] In the present invention, by doping titanium dioxide with copper ions or iron ions, the absorption rate of titanium dioxide in the ultraviolet light region with a wavelength less than 400 nm can be effectively improved.

[0023] The preparation method of a composite sunscreen agent containing natural polyphenols as described above is characterized in that the molar percentage of copper element or iron element in the modified titanium dioxide in step 103 is not more than 0.5%.

[0024] By controlling the molar percentage of copper ions doped in titanium dioxide to be no more than 0.5%, while the absorption rate of the modified titanium dioxide in the ultraviolet region with a wavelength less than 400 nm is increased, the absorption rate in the visible light range is slightly increased.

[0025] The preparation method of the above-mentioned composite sunscreen containing natural polyphenols is characterized in that, in step 102, the concentration of the hydrochloric acid solution is 0.09 mol / L to 0.11 mol / L, the soaking time is 20 h to 24 h, the drying temperature is 90 °C to 110 °C, and the drying time is not less than 24 h. In step 103, the calcination process is as follows: the temperature is raised to 400 °C to 800 °C at a heating rate of 2 °C / min and then held for 0.5 h to 3 h.

[0026] The powder prepared in step 102 of the present invention is anatase-type and rutile-type doped titanium dioxide. By calcination, the anatase-type can be converted into the rutile-type. Compared with the anatase-type, the rutile-type titanium dioxide has a higher absorption rate in the short-wavelength ultraviolet region, and has better weather resistance and non-powdering characteristics, which can make the performance of the composite sunscreen better.

[0027] The preparation method of the above-mentioned composite sunscreen containing natural polyphenols is characterized in that, in step two, the mass ratio of the modified titanium dioxide powder to the total mass of hexachlorocyclotriphosphazene and natural polyphenol compounds is 1:6 to 4:1, and the organic solvent is one of acetonitrile, tetrahydrofuran, and acetone.

[0028] By controlling the mass ratio of the modified titanium dioxide powder to the polyphosphazene shell material and controlling the addition amount of nano-silica, the particle size of the composite sunscreen can be adjusted, so that the particle size of the composite sunscreen is controlled at the micron level when preparing a sunscreen spray, reducing the risk of human inhalation.

[0029] The preparation method of the above-mentioned composite sunscreen containing natural polyphenols is characterized in that, in step two, the temperature of the first polymerization reaction is 20 °C to 70 °C, the duration of the first polymerization reaction is 0.2 h to 5 h, and the volume of the organic base is 6% to 16% of the volume of the organic solvent in step one; after the first polymerization reaction is completed, nano-silica and natural polyphenol compounds are added under ultrasonic stirring conditions, and the second polymerization reaction is carried out at 20 °C to 70 °C for 1 h to 5 h, and the mass ratio of the nano-silica to the natural polyphenol compounds is 1:1 to 2.2.

[0030] In the present invention, the organic base is one of trimethylamine, triethylamine, tripropylamine, and pyridine; by adding silica for the second polymerization reaction, a five-layer protective structure of natural polyphenol compound + silica, polyphosphazene, modified titanium dioxide, polyphosphazene, and natural polyphenol compound + silica is formed, effectively improving the sun protection effect of the composite sunscreen agent.

[0031] The present invention has the following advantages compared with the prior art:

[0032] 1. In the present invention, the composite sunscreen agent is set as a structure in which a polyphosphazene shell layer wraps modified titanium dioxide, enabling the synergistic effect between the polyphosphazene shell layer and the modified titanium dioxide core to form multiple protective barriers, effectively improving the ultraviolet light absorption efficiency of the composite sunscreen agent in the ultraviolet region, and isolating the modified titanium dioxide from the skin to avoid the harm caused by the photocatalytic effect of titanium dioxide on the skin; by adding natural polyphenol compounds in the polyphosphazene shell layer, the active oxygen generated by ultraviolet irradiation can be inhibited, the free radicals generated by the photocatalytic effect of titanium dioxide can be scavenged, cell apoptosis and autophagy can be regulated. At the same time, natural polyphenol compounds have a cyclic structure, and when excited by photons, electrons can undergo energy level transitions, thereby absorbing ultraviolet light and further enhancing the ultraviolet light absorption rate of the composite sunscreen agent.

[0033] 2. In the present invention, by modifying titanium dioxide, the ultraviolet light absorption rate of titanium dioxide is increased, and a polyphosphazene shell layer is wrapped on the surface of titanium dioxide, so that the composite sunscreen agent particles have multiple ultraviolet light protection layers, further enhancing the sun protection effect of the composite sunscreen agent.

[0034] 3. In the present invention, by adding nano-silica in the polyphosphazene shell layer, the ultraviolet light reflection ability of the composite sunscreen agent is improved by using the small size effect of nano-silica, so that the composite sunscreen agent has both the functions of reflecting and absorbing ultraviolet light; at the same time, nano-silica has the characteristics of odorless, non-toxic, good light transmittance, stable chemical properties, and easy compatibility with other components, and can cooperate with hexachlorocyclotriphosphazene and natural polyphenol compounds to wrap the modified titanium dioxide to avoid direct contact with the skin; and the added nano-silica is located on the surface layer and can absorb ultraviolet light, reducing the amount of ultraviolet light reaching the surface of the modified titanium dioxide.

[0035] 4. In the present invention, by using a polyphosphazene shell layer to coat titanium dioxide, the defect that nanoparticles are prone to agglomeration due to high surface energy can be reduced, thereby reducing the adhesion thickness of the composite sunscreen agent on the skin surface and improving the skin feel of the composite sunscreen agent.

[0036] 5. The present invention prepares polyphosphazene shell-coated modified titanium dioxide by using natural polyphenolic compounds with a conjugated structure and phenolic hydroxyl groups. The conjugated structure endows the natural polyphenolic compounds with good electron transfer ability, enabling them to accept the photo-generated electrons produced by the modified titanium dioxide. At the same time, the phenolic hydroxyl groups can form hydrogen bonds with the hydroxyl groups on the surface of titanium dioxide and adsorb on the surface of titanium dioxide, promoting the transfer of electrons from titanium dioxide to natural polyphenolic compounds, preventing the direct recombination of electrons and holes on the surface of titanium dioxide, inhibiting the recombination of electron-hole pairs, improving the photo-stability of titanium dioxide, and thus maintaining a long-lasting sun protection effect and reducing photocatalytic side effects.

[0037] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Brief Description of the Drawings

[0038] Figure 1 It is a transmission electron micrograph of the composite sunscreen in Example 1 of the present invention.

[0039] Figure 2 It is a graph of the ultraviolet light absorption results of the composite sunscreen in Example 1 of the present invention.

[0040] Figure 3 It is a graph of the test results of the free radical scavenging ability of the composite sunscreen in Example 1 of the present invention.

[0041] Figure 4 It is a transmission electron micrograph of the composite sunscreen in Example 2 of the present invention.

[0042] Figure 5 It is a graph of the ultraviolet light absorption results of the composite sunscreen in Example 2 of the present invention.

[0043] Figure 6 It is a graph of the test results of the free radical scavenging ability of the composite sunscreen in Example 2 of the present invention. Detailed Description of the Embodiments

[0044] Example 1

[0045] The composite sunscreen of this example includes a polyphosphazene shell and a core. The raw materials of the polyphosphazene shell include hexachlorocyclotriphosphazene and resveratrol, and the core is modified titanium dioxide doped with copper ions, and the molar percentage of copper element in the modified titanium dioxide is 0.1%.

[0046] The preparation method of the composite sunscreen in this example includes the following steps:

[0047] Step 1: Prepare modified titanium dioxide:

[0048] Step 101: Pour titanium dioxide and copper chloride into a sodium hydroxide solution with a concentration of 3 mol / L, stir evenly, then perform ultrasonic treatment for 20 min, transfer to an autoclave, and carry out hydrothermal reaction at 170 °C for 20 h to obtain a mixed solution;

[0049] Step 102: Wash and centrifuge the mixed solution obtained in Step 101, then soak it in a hydrochloric acid solution with a concentration of 0.1 mol / L for 20 h, and then wash, centrifuge, dry, and grind it in sequence to obtain a powder; the drying temperature is 100 °C, and the drying duration is not less than 24 h;

[0050] Step 103: Spread the powder obtained in Step 102 evenly between two ceramic plates, use ultrasonic waves to disperse the powder particles, then place it in an inert gas environment for calcination, and obtain modified titanium dioxide powder after grinding. Disperse 200 g of the modified titanium dioxide powder, 152 g of hexachlorocyclotriphosphazene, and 200 g of resveratrol in 3600 mL of acetonitrile under ultrasonic waves to obtain a dispersion; the process of the calcination is: raise the temperature to 600 °C at a heating rate of 2 °C / min and then hold for 1 h;

[0051] Step Two: Add 360 mL of triethylamine to the dispersion obtained in Step One under ultrasonic conditions, and carry out the first polymerization reaction at a temperature of 60 °C for 3 h to obtain a mixed solution;

[0052] Step Three: Centrifuge the solid product from the mixed solution obtained in Step Two, and then wash and dry it in sequence to obtain a composite sunscreen agent.

[0053] In this embodiment, resveratrol can also be replaced by one of catechins, tea polyphenols, phloretin, honokiol, hesperetin, tannic acid, coenzyme panthenol, flavonoids, flavanols, dihydroflavonoids, and isoflavonoids other than resveratrol.

[0054] Perform microscopic analysis on the composite sunscreen agent obtained in this embodiment, as Figure 1 shown, the composite sunscreen agent forms a granular structure, with an average particle size of about 200 nm and good dispersibility, and no agglomeration phenomenon occurs.

[0055] Perform ultraviolet light absorption tests on the composite sunscreen agent obtained in this embodiment and unmodified titanium dioxide respectively, as Figure 2 shown, compared with unmodified titanium dioxide, the absorbance of the composite sunscreen agent is significantly increased in the range of wavelengths less than 400 nm. However, due to the doping of a small amount of copper ions in the composite sunscreen agent, the absorbance also increases slightly in the range of wavelengths greater than 400 nm. The composite sunscreen agent has enhanced absorption of ultraviolet light in the range of wavelengths less than 400 nm compared with traditional titanium dioxide, improving the sunscreen effect.

[0056] The compound sunscreen agents with concentrations of 2 mg / mL and 3 mg / mL in this example were respectively mixed with DPPH (free radical) solution and then left to stand for the free radical scavenging ability test. The results are as Figure 3 shown. The compound sunscreen agents with both concentrations had good free radical scavenging effects within 8 hours of standing.

[0057] In summary, the compound sunscreen agent of this example has the characteristics of good dispersibility, excellent sunscreen effect, and strong free radical scavenging ability.

[0058] Example 2

[0059] The compound sunscreen agent of this example includes a polyphosphazene shell layer and a core. The raw materials of the polyphosphazene shell layer include hexachlorocyclotriphosphazene, resveratrol, and nano-silica. The core is modified titanium dioxide doped with copper ions, and the molar percentage of copper element in the modified titanium dioxide is 0.1%.

[0060] The preparation method of the compound sunscreen agent in this example includes the following steps:

[0061] Step 1. Prepare modified titanium dioxide:

[0062] Step 101. Pour titanium dioxide and copper chloride into a sodium hydroxide solution with a concentration of 5 mol / L, stir evenly, then perform ultrasonic treatment for 20 min, transfer to an autoclave, and carry out hydrothermal reaction at 180 °C for 24 h to obtain a mixed solution;

[0063] Step 102. Wash and centrifuge the mixed solution obtained in Step 101, then soak it in a hydrochloric acid solution with a concentration of 0.11 mol / L for 24 h, and then wash, centrifuge, dry, and grind it in sequence to obtain a powder; the drying temperature is 90 °C, and the drying duration is not less than 24 h;

[0064] Step 103. Spread the powder obtained in Step 102 on the surface of a ceramic plate, use ultrasonic waves to disperse the powder particles, then place it in an inert gas environment for calcination, and grind it to obtain modified titanium dioxide powder. Disperse 200 g of modified titanium dioxide powder, 180 g of hexachlorocyclotriphosphazene, and 220 g of resveratrol in 3500 mL of acetone under ultrasonic waves to obtain a dispersion; the process of the calcination is: raise the temperature to 550 °C at a heating rate of 2 °C / min and then hold for 0.5 h;

[0065] Step 2. Add 460 mL of triethylamine to the dispersion obtained in Step 1 under ultrasonic conditions, and carry out the first polymerization reaction at 70 °C for 5 h. Then add 25 g of resveratrol and 15 g of nano-silica under ultrasonic conditions, and carry out the second polymerization reaction at 20 °C for 5 h to obtain a mixed solution;

[0066] Step 3: Centrifuge the solid product from the mixture obtained in Step 2, and then wash and dry it successively to obtain the composite sunscreen agent.

[0067] Perform microscopic analysis on the composite sunscreen agent obtained in this example, as Figure 4 shown. The composite sunscreen agent forms a granular structure, with an average particle size of about 350 nm and good dispersibility, and no agglomeration phenomenon occurs.

[0068] Perform ultraviolet light absorption tests on the composite sunscreen agent obtained in this example and unmodified titanium dioxide respectively, as Figure 5 shown. Compared with unmodified titanium dioxide, the absorbance of this composite sunscreen agent increases in the range of wavelengths less than 400 nm, especially significantly increases in the range of wavelengths from 250 nm to 400 nm. However, due to the doping of a small amount of copper ions in the composite sunscreen agent, the absorbance also increases slightly in the range of wavelengths greater than 400 nm. This composite sunscreen agent has enhanced absorption of ultraviolet light in the range of wavelengths less than 400 nm compared with traditional titanium dioxide, improving the sunscreen effect.

[0069] Mix the composite sunscreen agents with concentrations of 2 mg / mL and 3 mg / mL in this example with DPPH (free radical) solution respectively and let them stand still, and perform free radical scavenging ability tests. The results are as Figure 6 shown. The composite sunscreen agents with both concentrations have good free radical scavenging effects within 8 hours of standing still.

[0070] In summary, the composite sunscreen agent of this example has the characteristics of good dispersibility, excellent sunscreen effect, and strong free radical scavenging ability.

[0071] Example 3

[0072] The composite sunscreen agent of this example includes a polyphosphazene shell layer and a core. The raw materials of the polyphosphazene shell layer include hexachlorocyclotriphosphazene and naringenin, and the core is modified titanium dioxide doped with copper ions. The molar percentage of copper element in this modified titanium dioxide is 0.15%.

[0073] The preparation method of the composite sunscreen agent in this example includes the following steps:

[0074] Step 1: Prepare modified titanium dioxide:

[0075] Step 101: Pour titanium dioxide and copper sulfate into a sodium hydroxide solution with a concentration of 5 mol / L, stir evenly, then perform ultrasonic treatment for 20 min, transfer to an autoclave, and carry out hydrothermal reaction at 150 °C for 21 h to obtain a mixed solution;

[0076] Step 102: After washing and centrifuging the mixed solution obtained in Step 101, soak it in a hydrochloric acid solution with a concentration of 0.11 mol / L for 21 h, and then wash, centrifuge, dry, and grind it in sequence to obtain a powder; the drying temperature is 90 °C, and the drying duration is not less than 24 h;

[0077] Step 103: Spread the powder obtained in Step 102 on the surface of a ceramic plate, disperse the powder particles by ultrasonic waves, and then place it in an inert gas environment for calcination. After grinding, modified titanium dioxide powder is obtained. Disperse 200 g of the modified titanium dioxide powder, 150 g of hexachlorocyclotriphosphazene, and 750 g of naringenin in 4500 mL of tetrahydrofuran under ultrasonic waves to obtain a dispersion; the process of the calcination is: raise the temperature to 500 °C at a heating rate of 2 °C / min and then keep it warm for 1.5 h;

[0078] Step Two: Add 710 mL of triethylamine to the dispersion obtained in Step One under ultrasonic conditions, and carry out the first polymerization reaction for 5 h at a temperature of 20 °C to obtain a mixed solution;

[0079] Step Three: Centrifuge the solid product from the mixed solution obtained in Step Two, and then wash and dry it in sequence to obtain a composite sunscreen agent.

[0080] After testing, the composite sunscreen agent prepared in this example has good dispersibility. The average particle size of this composite sunscreen agent is about 3 μm; compared with titanium dioxide, the absorption effect of this composite sunscreen agent in the range of ultraviolet light less than 400 nm is significantly enhanced, and when the composite sunscreen agent with concentrations of 2 mg / mL and 3 mg / mL is mixed with DPPH (free radical) solution and left to stand respectively, both have good free radical scavenging effects within 8 hours.

[0081] Example 4

[0082] The composite sunscreen agent of this example includes a polyphosphazene shell layer and a core. The raw materials of the polyphosphazene shell layer include hexachlorocyclotriphosphazene and EGCG (epigallocatechin gallate), and the core is modified titanium dioxide doped with copper ions. The molar percentage of copper element in this modified titanium dioxide is 0.2%.

[0083] The preparation method of the composite sunscreen agent in this example includes the following steps:

[0084] Step One: Prepare modified titanium dioxide:

[0085] Step 101: Pour titanium dioxide and copper chloride into a sodium hydroxide solution with a concentration of 0.5 mol / L, stir evenly, then carry out ultrasonic treatment for 30 min, transfer it to an autoclave, and carry out a hydrothermal reaction at 180 °C for 24 h to obtain a mixed solution;

[0086] Step 102: After washing and centrifuging the mixed solution obtained in Step 101, soak it in a hydrochloric acid solution with a concentration of 0.09 mol / L for 24 h, and then wash, centrifuge, dry, and grind it in sequence to obtain a powder; the drying temperature is 110 °C, and the drying duration is not less than 24 h;

[0087] Step 103: Spread the powder obtained in Step 102 on the surface of a ceramic plate, use ultrasonic waves to disperse the powder particles, and then place it in an inert gas environment for calcination. After grinding, obtain modified titanium dioxide powder. Disperse 400 g of modified titanium dioxide powder, 75 g of hexachlorocyclotriphosphazene, and 70 g of EGCG in 1500 mL of acetone under ultrasonic waves to obtain a dispersion; the process of the calcination is: raise the temperature to 400 °C at a heating rate of 2 °C / min and then hold for 3 h;

[0088] Step Two: Add 160 mL of trimethylamine to the dispersion obtained in Step One under ultrasonic conditions, and carry out the first polymerization reaction at a temperature of 70 °C for 0.2 h to obtain a mixed solution;

[0089] Step Three: Centrifuge the solid product from the mixed solution obtained in Step Two, and then wash and dry it in sequence to obtain a composite sunscreen agent.

[0090] Copper chloride in this embodiment can also be replaced by copper acetate.

[0091] After testing, the composite sunscreen agent prepared in this embodiment has good dispersibility. The average particle size of this composite sunscreen agent is about 150 nm; compared with titanium dioxide, the absorption effect of this composite sunscreen agent in the range of ultraviolet light less than 400 nm is significantly enhanced, and when the composite sunscreen agents with concentrations of 2 mg / mL and 3 mg / mL are respectively mixed with DPPH (free radical) solution and left standing, both have good free radical scavenging effects within 8 hours.

[0092] Example 5

[0093] The composite sunscreen agent of this embodiment includes a polyphosphazene shell layer and a core. The raw materials of the polyphosphazene shell layer include hexachlorocyclotriphosphazene, ellagic acid, and nano-silica. The core is modified titanium dioxide doped with copper ions, and the molar percentage of copper element in this modified titanium dioxide is 0.2%.

[0094] The preparation method of the composite sunscreen agent in this embodiment includes the following steps:

[0095] Step One: Prepare modified titanium dioxide:

[0096] Step 101: Pour titanium dioxide and copper chloride into a sodium hydroxide solution with a concentration of 4.5 mol / L, stir evenly, then perform ultrasonic treatment for 20 min, transfer it to an autoclave, and carry out hydrothermal reaction at 180 °C for 22 h to obtain a mixed solution;

[0097] Step 102: Wash and centrifuge the mixed solution obtained in Step 101, then soak it in a hydrochloric acid solution with a concentration of 0.1 mol / L for 24 h, and then perform washing, centrifugation, drying and grinding in sequence to obtain a powder; the drying temperature is 95 °C, and the drying duration is not less than 24 h;

[0098] Step 103: Spread the powder obtained in Step 102 on the surface of a ceramic plate, use ultrasonic waves to disperse the powder particles, then place it in an inert gas environment for calcination, and obtain modified titanium dioxide powder after grinding. Disperse 200 g of modified titanium dioxide powder, 200 g of hexachlorocyclotriphosphazene, and 210 g of ellagic acid in 3500 mL of acetonitrile under ultrasonic waves to obtain a dispersion; the process of the calcination is: increase the temperature to 800 °C at a heating rate of 2 °C / min and then hold for 0.5 h;

[0099] Step Two: Add 250 mL of pyridine to the dispersion obtained in Step One under ultrasonic conditions, and carry out the first polymerization reaction at 60 °C for 4 h. Then add 17.5 g of ellagic acid and 17.5 g of nano-titanium dioxide under ultrasonic conditions, and carry out the second polymerization reaction at 30 °C for 4.5 h to obtain a mixed solution;

[0100] Step Three: Centrifuge the mixed solution obtained in Step Two to separate the solid product, and then perform washing and drying in sequence to obtain a composite sunscreen agent.

[0101] After testing, the composite sunscreen agent prepared in this example has good dispersibility. The average particle size of this composite sunscreen agent is about 400 nm; compared with titanium dioxide, the absorption effect of this composite sunscreen agent in the range of ultraviolet light less than 400 nm is significantly enhanced, and when the composite sunscreen agents with concentrations of 2 mg / mL and 3 mg / mL are respectively mixed with DPPH (free radical) solution and left standing, both have good free radical scavenging effects within 8 hours.

[0102] Example 6

[0103] The composite sunscreen agent of this example includes a polyphosphazene shell layer and a core. The raw materials of the polyphosphazene shell layer include hexachlorocyclotriphosphazene, curcumin and nano-titanium dioxide, and the core is modified titanium dioxide doped with copper ions. The molar percentage of copper element in this modified titanium dioxide is 0.05%.

[0104] The preparation method of the composite sunscreen agent in this example includes the following steps:

[0105] Step 1. Preparation of modified titanium dioxide:

[0106] Step 101. Pour titanium dioxide and copper carbonate into a sodium hydroxide solution with a concentration of 4 mol / L, stir evenly, then perform ultrasonic treatment for 25 min, transfer to an autoclave, and carry out hydrothermal reaction at 175 °C for 22 h to obtain a mixed solution;

[0107] Step 102. After washing and centrifuging the mixed solution obtained in Step 101, soak it in a hydrochloric acid solution with a concentration of 0.1 mol / L for 24 h, and then perform washing, centrifuging, drying, and grinding in sequence to obtain a powder; the drying temperature is 100 °C, and the drying duration is not less than 24 h;

[0108] Step 103. Spread the powder obtained in Step 102 on the surface of a ceramic plate, use ultrasonic waves to disperse the powder particles, and then place it in an inert gas environment for calcination. After grinding, modified titanium dioxide powder is obtained. Disperse 400 g of modified titanium dioxide powder, 80 g of hexachlorocyclotriphosphazene, and 50 g of curcumin in 1500 mL of acetonitrile under ultrasonic waves to obtain a dispersion; the process of the calcination is: raise the temperature to 800 °C at a heating rate of 2 °C / min and then hold for 0.5 h;

[0109] Step 2. Add 120 mL of tripropylamine to the dispersion obtained in Step 1 under ultrasonic conditions, and carry out the first polymerization reaction at 60 °C for 4 h. Then add 15 g of curcumin and 7 g of nano-titanium dioxide under ultrasonic conditions, and carry out the second polymerization reaction at 70 °C for 1 h to obtain a mixed solution;

[0110] Step 3. Centrifuge the mixed solution obtained in Step 2 to separate the solid product, and then perform washing and drying in sequence to obtain a composite sunscreen agent.

[0111] After testing, the composite sunscreen agent prepared in this example has good dispersibility. The average particle size of this composite sunscreen agent is about 300 nm; compared with titanium dioxide, the absorption effect of this composite sunscreen agent in the range of ultraviolet light less than 400 nm is significantly enhanced. Moreover, when the composite sunscreen agents with concentrations of 2 mg / mL and 3 mg / mL are respectively mixed with DPPH (free radical) solution and left standing, both have good free radical scavenging effects within 8 hours.

[0112] Example 7

[0113] The composite sunscreen agent of this example includes a polyphosphazene shell layer and a core. The raw materials of the polyphosphazene shell layer include hexachlorocyclotriphosphazene and EGCG, and the core is modified titanium dioxide doped with iron ions. The molar percentage of iron element in this modified titanium dioxide is 0.02%.

[0114] The preparation method of the composite sunscreen agent in this embodiment includes the following steps:

[0115] Step 1: Prepare modified titanium dioxide:

[0116] Step 101: Pour titanium dioxide and ferric chloride into a sodium hydroxide solution with a concentration of 0.5 mol / L, stir evenly, then carry out ultrasonic treatment for 30 min, transfer to an autoclave, and carry out hydrothermal reaction at 180 °C for 24 h to obtain a mixed solution;

[0117] Step 102: After washing and centrifuging the mixed solution obtained in Step 101, soak it in a hydrochloric acid solution with a concentration of 0.1 mol / L for 24 h, and then carry out washing, centrifuging, drying and grinding in sequence to obtain a powder; the drying temperature is 100 °C, and the drying duration is not less than 24 h;

[0118] Step 103: Spread the powder obtained in Step 102 on the surface of a ceramic plate, use ultrasonic waves to disperse the powder particles, and then place it in an inert gas environment for calcination. After grinding, obtain modified titanium dioxide powder. Disperse 400 g of modified titanium dioxide powder, 116 g of hexachlorocyclotriphosphazene, and 29 g of EGCG in 1500 mL of acetone under ultrasonic waves to obtain a dispersion; the process of the calcination is: increase the temperature to 400 °C at a heating rate of 2 °C / min and then keep it warm for 3 h;

[0119] Step 2: Add 160 mL of trimethylamine to the dispersion obtained in Step 1 under ultrasonic conditions, and carry out the first polymerization reaction at 70 °C for 0.2 h to obtain a mixed solution;

[0120] Step 3: Centrifuge the solid product from the mixed solution obtained in Step 2, and then carry out washing and drying in sequence to obtain the composite sunscreen agent.

[0121] In this embodiment, ferric chloride can also be replaced by ferric acetate.

[0122] After testing, the composite sunscreen agent prepared in this embodiment has good dispersibility, and the average particle size of the composite sunscreen agent is about 140 nm; compared with titanium dioxide, the absorption effect of the composite sunscreen agent in the range of ultraviolet light less than 400 nm is enhanced, and when the composite sunscreen agent with concentrations of 2 mg / mL and 3 mg / mL is mixed with DPPH (free radical) solution and left standing, both have good free radical scavenging effects within 8 hours.

[0123] Example 8

[0124] The composite sunscreen agent of this embodiment includes a polyphosphazene shell layer and a core. The raw materials of the polyphosphazene shell layer include hexachlorocyclotriphosphazene, naringenin, and nano-silica. The core is modified titanium dioxide doped with iron ions, and the molar percentage of iron element in the modified titanium dioxide is 0.12%.

[0125] The preparation method of the composite sunscreen agent in this embodiment includes the following steps:

[0126] Step 1. Prepare modified titanium dioxide:

[0127] Step 101. Pour titanium dioxide and ferric sulfate into a sodium hydroxide solution with a concentration of 5 mol / L, stir evenly, then perform ultrasonic treatment for 20 min, transfer to an autoclave, and carry out hydrothermal reaction at 160 °C for 23 h to obtain a mixed solution;

[0128] Step 102. After washing and centrifuging the mixed solution obtained in Step 101, soak it in a hydrochloric acid solution with a concentration of 0.11 mol / L for 23 h, and then perform washing, centrifuging, drying, and grinding in sequence to obtain a powder; the drying temperature is 90 °C, and the drying duration is not less than 24 h;

[0129] Step 103. Spread the powder obtained in Step 102 on the surface of a ceramic plate, use ultrasonic waves to disperse the powder particles, and then place it in an inert gas environment for calcination. After grinding, obtain modified titanium dioxide powder. Disperse 200 g of modified titanium dioxide powder, 840 g of hexachlorocyclotriphosphazene, and 360 g of naringenin in 8000 mL of tetrahydrofuran under ultrasonic waves to obtain a dispersion; the process of the calcination is: raise the temperature to 650 °C at a heating rate of 2 °C / min and then keep it warm for 1.3 h;

[0130] Step 2. Add 480 mL of pyridine to the dispersion obtained in Step 1 under ultrasonic conditions, and carry out the first polymerization reaction at 30 °C for 5 h. Then, add 80 g of naringenin and 60 g of nano-silica under ultrasonic conditions, and carry out the second polymerization reaction at 30 °C for 4 h to obtain a mixed solution;

[0131] Step 3. Centrifuge the mixed solution obtained in Step 2 to separate the solid product, and then perform washing and drying in sequence to obtain the composite sunscreen agent.

[0132] After testing, the composite sunscreen agent prepared in this embodiment has good dispersibility. The average particle size of the composite sunscreen agent is about 12 μm; compared with titanium dioxide, the absorption effect of the composite sunscreen agent in the range of ultraviolet light less than 400 nm is significantly enhanced. Moreover, when the composite sunscreen agent with concentrations of 2 mg / mL and 3 mg / mL is mixed with DPPH (free radical) solution and left standing, both have good free radical scavenging effects within 8 hours.

[0133] The above are only the preferred embodiments of the present invention, and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent structural transformations made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A composite sunscreen containing natural polyphenols, characterized in that, It includes a polyphosphazene shell and a core. The raw materials of the polyphosphazene shell include hexachlorocyclotriphosphazene and natural polyphenolic compounds, and the core is modified titanium dioxide.

2. The composite sunscreen containing natural polyphenols according to claim 1, characterized in that, The raw materials of the polyphosphazene shell further include nano-silica, and the mass of the nano-silica is not more than 5% of the total mass of the raw materials of the polyphosphazene shell.

3. The composite sunscreen containing natural polyphenols according to claim 1, characterized in that, The natural polyphenolic compound is one of resveratrol, curcumin, catechins, tea polyphenols, phloretin, magnolol, hesperetin, ellagic acid, gallic acid, tannic acid, coenzyme panthenol, flavonoids, flavanols, dihydroflavonoids and isoflavonoids, and the mass of the natural polyphenolic compound accounts for 20% - 80% of the total mass of the raw materials of the polyphosphazene shell.

4. A preparation method of a composite sunscreen containing natural polyphenols as described in any one of claims 1 to 3, characterized in that, The preparation method includes the following steps: Step 1: Disperse the modified titanium dioxide powder, hexachlorocyclotriphosphazene and natural polyphenolic compounds in an organic solvent under ultrasonic stirring to obtain a dispersion. Step 2: Add an organic base to the dispersion obtained in Step 1 under ultrasonic stirring to carry out a first polymerization reaction to obtain a mixed solution. Step 3: Centrifuge the solid product of the mixed solution obtained in Step 2, and then wash and dry it in sequence to obtain a composite sunscreen.

5. The preparation method of a composite sunscreen containing natural polyphenols according to claim 4, characterized in that, The preparation method of the modified titanium dioxide powder in Step 1 includes the following steps: Step 101: Pour titanium dioxide into a sodium hydroxide solution and stir, and carry out ultrasonic and hydrothermal reactions in sequence to obtain a mixed solution. Step 102: Wash and centrifuge the mixed solution obtained in Step 101, then soak it in a hydrochloric acid solution, and then wash, centrifuge, dry and grind it in sequence to obtain a powder. Step 103: Spread the powder obtained in Step 102 between two ceramic plates, use ultrasonic waves to disperse the powder particles, and then place it in an inert gas environment for calcination, and grind it to obtain the modified titanium dioxide powder.

6. The preparation method of a composite sunscreen containing natural polyphenols according to claim 5, characterized in that, In the stirring process of Step 101, a copper salt or an iron salt is added. The copper salt is one of copper chloride, copper sulfate, copper carbonate and copper acetate, and the iron salt is one of ferric chloride, ferric sulfate and ferric acetate. The concentration of the sodium hydroxide solution is 0.5mol / L - 5mol / L, the temperature of the hydrothermal reaction is 150°C - 180°C, and the duration of the hydrothermal reaction is 20h - 24h.

7. The preparation method of a composite sunscreen containing natural polyphenols according to claim 5, characterized in that, The molar percentage of copper element or iron element in the modified titanium dioxide in Step 103 is not more than 0.5%.

8. The preparation method of a composite sunscreen containing natural polyphenols according to claim 5, characterized in that, The concentration of the hydrochloric acid solution in Step 102 is 0.09mol / L - 0.11mol / L, the soaking duration is 20h - 24h, the drying temperature is 90°C - 110°C, and the drying duration is not less than 24h. The calcination process in Step 103 is: raise the temperature to 400°C - 800°C at a heating rate of 2°C / min and then keep it warm for 0.5h - 3h.

9. The preparation method of a composite sunscreen containing natural polyphenols according to claim 4, characterized in that, In Step 1, the ratio of the mass of the modified titanium dioxide powder to the total mass of the hexachlorocyclotriphosphazene and natural polyphenolic compounds is 1:6 - 4:1, and the organic solvent is one of acetonitrile, tetrahydrofuran and acetone.

10. The preparation method of a composite sunscreen containing natural polyphenols according to claim 4, characterized in that, In Step 2, the temperature of the first polymerization reaction is 20°C to 70°C, the duration of the first polymerization reaction is 0.2 h to 5 h, and the volume of the organic base is 6% to 16% of the volume of the organic solvent in Step 1; after the first polymerization reaction is completed, nano-silica and natural polyphenolic compounds are added under ultrasonic stirring conditions, and a second polymerization reaction is carried out at 20°C to 70°C for 1 h to 5 h, and the mass ratio of the nano-silica to the natural polyphenolic compounds is 1:1 to 2.2.

Images