A triazine sunscreen microcapsule and its preparation method and application

Abstract

The invention belongs to the technical field of fine chemicals, and discloses a triazine sunscreen microcapsule and a preparation method thereof. The method comprises the following steps: dissolving bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone in an organic solvent, adding an emulsifier and a gelatin solution for homogenization and emulsification, and performing rotary evaporation of the emulsified system at 40 to 60° C. and a negative pressure of ‑0.2 to 0.‑0.5 MPa to obtain a submicron sunscreen particle dispersion; then mixing the gelatin solution, the sodium alginate solution and the submicron sunscreen particle dispersion, adjusting the pH value of the mixed system to 4.0 to 4.5, performing complex coagulation at 40 to 50° C., adding a calcium chloride solution to the gel system for crosslinking at 5 to 10° C., adjusting the pH value of the system to 6.0 to 6.5, and drying to obtain a triazine sunscreen microcapsule. The microcapsule has good ultraviolet absorption, and at the same time reduces the penetration of chemical ultraviolet absorbers into the skin, causing skin irritation such as photosensitivity and phototoxic reactions.

Description

Technical Field

[0001] The present invention belongs to the technical field of fine chemicals, and more specifically, relates to a triazine sunscreen microcapsule and a preparation method and application thereof. Technical Background

[0002] The spectrum of sunlight is very wide and can be divided into three types: ultraviolet radiation (200-400nm), visible light (400-700nm), and infrared radiation (700-3000nm). Although ultraviolet radiation only accounts for 5% of all radiation, it plays an important role in photoaging and skin cancer. The International Commission on Illumination divides ultraviolet rays into three specific bands, among which 100-280nm ultraviolet rays are called short-wave ultraviolet rays (UVC), 280-315nm ultraviolet rays are called medium-wave ultraviolet rays (UVB), and 315-400nm ultraviolet rays are called long-wave ultraviolet rays (UVA). Generally speaking, due to the absorption of the atmosphere, UVC cannot reach the earth's surface, and only medium-wave ultraviolet rays (UVB) and long-wave ultraviolet rays (UVA) can reach the earth's surface. UVB can penetrate into the stratum corneum of human skin. A small amount of UVB irradiation can promote metabolism and the formation of vitamin D in the body, but long-term exposure will tan the skin, causing sunburn and erythema. UVA can penetrate the epidermis and reach the dermis. After long-term exposure to UVA, the elastic fibers and collagen fibers of the skin will be severely damaged, causing melanin precipitation, making the skin darker and rougher. Over time, the pigment accumulates into dark spots. The International Agency for Research on Cancer pointed out that there is enough evidence to prove that ultraviolet radiation is a human carcinogen (Gallagher RP, Lee T K. Adverse effects of ultraviolet radiation: a brief review [J]. Progress in Biophysics and Molecular Biology, 2006, 92 (1): 119-131).

[0003] As people gradually realize the damage of ultraviolet radiation to the skin, more and more people will use sunscreen products to protect their skin from ultraviolet damage when going out, such as sunscreen, sunscreen spray, etc. However, the national health department strictly stipulates the types and dosages of organic ultraviolet absorbers that can be added to sunscreen products. A large number of studies have shown that the safety and skin permeability of organic ultraviolet absorbers are still issues that consumers are more concerned about. The European Commission's Consumer Products Scientific Committee pointed out that many sunscreen molecules can penetrate the skin and cause photosensitivity, phototoxic reactions and skin irritation (Gonzalez H. Percutaneous absorption with emphasis on sunscreens [J]. Photochemical & Photobiological Sciences, 2010, 9 (4): 482-488).

[0004] Bis-ethylhexyloxyphenol methoxyphenyl triazine is a new type of oil-soluble, strong broad-spectrum sunscreen that can absorb both UVA and UVB. It has a good absorption effect on UVA, but a general absorption effect on UVB. Octyl triazone is an oil-soluble UVB sunscreen that has a strong absorption effect on UVB, but has almost no absorption ability for UVA. Therefore, the combination of the two can make up for their respective shortcomings and give the sunscreen a strong spectrum absorption ability. However, since both are insoluble in water, they need to be used with highly polar oils such as C 12～15 Alkyl benzoic acid esters, caprylic acid capric acid triglyceride, dicaprylyl carbonate and the like are used in combination, which not only reduces the refreshing property of sunscreen products, but also the oily raw materials may penetrate into the skin together with chemical ultraviolet absorbers, causing adverse reactions such as skin allergy, phototoxicity and skin irritation. At present, some studies have proved that bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S) can cause allergic contact dermatitis (Eric Chatelain, Bernard Gabard "Photostabilization of Butyl methoxydibenzoylmethane (Avobenzone) and Ethylhexylmethoxycinnamate by Bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S), a New UV Broadband Filter," Photochemistry and Photobiology, 74 (3), 401-406, (1 September 2001)).

[0005] The emergence of capsule technology just meets people's pursuit of "pursuing naturalness, advocating health, requiring convenience, and advocating deliciousness" for food. There are many methods for preparing microcapsules, including coacervation, phase separation in organic phase system, interfacial polymerization, emulsion polymerization, etc. The phase separation method in organic phase system requires a large amount of organic solvents, which is not environmentally friendly, while interfacial polymerization and emulsion polymerization require semi-synthetic polymers or synthetic polymer materials, which have certain toxicity and poor biocompatibility. Therefore, applying organic ultraviolet absorbers on the surface of the human body while protecting the skin from harm and making the sunscreen have good freshness has become a difficult problem in the current research and development of sunscreen products. Summary of the invention

[0006] In order to solve the deficiencies and shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a method for preparing triazine sunscreen microcapsules. The method prepares a submicron sunscreen particle dispersion by a solvent volatilization method, and then mixes a polymer wall material gelatin with good biocompatibility with sodium alginate to perform complex coacervation coating on the sunscreen particles to form a triazine sunscreen microcapsule with a core-shell structure. The invention solves the following problems: (1) Most triazine organic UV absorbers need to be dissolved in oils and fats during use, which causes a greasy feeling during use; (2) triazine organic UV absorbers have poor and uneven dispersion in water and refreshing creams, and organic UV absorbers directly contact the skin and cause damage to the skin; (3) chemical UV absorbers in sunscreen products on the market cause skin allergies and other problems.

[0007] Another object of the present invention is to provide triazine sunscreen microcapsules prepared by the above method. The triazine sunscreen microcapsules have excellent safety, sunscreen properties, high dispersibility, stability, and can absorb in a wide ultraviolet band.

[0008] Another object of the present invention is to provide application of the above triazine sunscreen microcapsules.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] A method for preparing triazine sunscreen microcapsules comprises the following steps:

[0011] S1. Add gelatin to deionized water, stir and heat at 40°C to dissolve, and obtain a clear gelatin solution; add sodium alginate powder to deionized water, stir and heat at 40°C to dissolve, and obtain a clear sodium alginate solution.

[0012] S2. Dissolving the sunscreen agents bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone in an organic solvent, adding an emulsifier and 1 to 10 wt % gelatin solution for homogenization and emulsification to obtain an emulsified system;

[0013] S3. The emulsified system is subjected to rotary evaporation at 40 to 60° C. and a negative pressure of -0.2 to 0.-0.5 MPa to obtain a submicron sunscreen particle dispersion;

[0014] S4. The gelatin solution, the sodium alginate solution and the submicron sunscreen particle dispersion are mixed, the pH value of the mixed system is adjusted to 4.0 to 4.5, and the mixture is subjected to complex coagulation at 40 to 50° C. to obtain a gel system;

[0015] S5. Add calcium chloride solution to the gel system and perform cross-linking at 5-10° C. for 30-60 min. After the cross-linking is completed, adjust the pH value of the system to 6.0-6.5, dry, and obtain triazine sunscreen microcapsules.

[0016] Preferably, the mass ratio of bis-ethylhexyloxyphenol methoxyphenyl triazine to octyl triazone in the sunscreen in step S1 is 1:(0.1-0.3); the mass ratio of the sunscreen to the organic solvent is 1:(2-5); the organic solvent is dichloromethane, petroleum ether, n-hexane or ethyl acetate; the emulsifier is one or more of Span 20, Tween-80 or potassium hexadecyl phosphate, and the emulsifier is 0.7-1.3wt% of the organic solvent; the gelatin is type B gelatin.

[0017] Preferably, the homogenization and emulsification rate in step S1 is 6000-18000 rpm, and the homogenization and emulsification time is 3-10 min.

[0018] Preferably, the rotation speed of the rotary evaporation in step S2 is 50 to 200 rpm, and the time of the rotary evaporation is 50 to 100 min.

[0019] Preferably, the particle size of the submicron sunscreen particle dispersion in step S2 is 400 nm to 4 μm.

[0020] Preferably, the concentration of the gelatin solution in step S3 is 0.5-1wt%, and the concentration of the sodium alginate solution is 0.1-1wt%; the mass ratio of the gelatin solution, the sodium alginate solution and the submicron sunscreen particle dispersion is (1-10):1:(1-2); the gelatin solution and the sodium alginate solution are 0.5-1wt% of the total mass of the gelatin solution, the sodium alginate solution and the submicron sunscreen particle dispersion.

[0021] Preferably, the calcium chloride in the calcium chloride solution in step S4 is 0.1-0.5 wt % of the gel system.

[0022] Preferably, the drying in step S4 is freeze drying or spray drying.

[0023] A triazine sunscreen microcapsule is prepared by the method described.

[0024] The triazine sunscreen microcapsules of the present invention have high dispersibility and broad-spectrum protection. The hydrophobic and oil-soluble bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone are compressed into submicron-level particles with good dispersibility in water by a solvent volatilization method, and then wrapped by natural materials. Bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone are coated with gelatin-sodium alginate with good hydrophilicity and biocompatibility, which can not only greatly improve the stability, dispersibility and hydrophilicity of bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone, but also effectively isolate the skin from the triazine sunscreen, and reduce the irritation of the organic ultraviolet absorber itself to the skin. It can be seen that the prospect of bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone microcapsules is widely used, has strong operability, and is easier to obtain a new type of sunscreen with high stability and safety.

[0025] Working principle of the present invention:

[0026] If traditional sunscreen formulations need to be added to water, they must be dissolved in polar oils (such as C 12～15 When a small amount of non-polar organic solvent is dispersed in water, the non-polar organic solvent is the internal phase and water is the continuous external phase, which can form an oil-in-water (O / W) emulsion, but this mixture is unstable. If there is no emulsifier, the oil-in-water emulsion will usually be completely separated in a few seconds. Gelatin has both hydrophilic and lipophilic groups. The surfactant protein can be used as an emulsifier to stabilize the oil-water interface to prevent the emulsion from separating. However, the emulsification effect of gelatin colloid as an emulsifier is not very good, and it usually tends to form a large particle size emulsion. Adding a small amount of emulsifier (such as Span 20 or Span 80, etc.) can obtain an emulsion with a smaller particle size. When the sunscreen agents bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone are dissolved in an organic solvent to form an emulsion, the organic solvent continuously evaporates during the rotary evaporation process. Since the emulsion is heated evenly during the rotary evaporation, the spherical droplets continue to shrink evenly, and when the amount of organic solvent is evaporated to a level that is insufficient to dissolve the sunscreen agent, the sunscreen agent will precipitate and gradually form spherical micro-nano particles (i.e., particle dispersions). Compared with conventional irregular sunscreen agent particles, the micro-nano particles have a smaller particle size and better dispersion properties in water.

[0027] Gelatin is an amphoteric polymer material with many groups on its molecular chain. Among them, the change in the charge on the amino and carboxyl groups has the greatest impact on the entire complex coagulation process. The isoelectric point of type B gelatin is between 4.5 and 6.0. When the pH is greater than its isoelectric point, the amino group becomes -NH2, and the carboxyl group becomes a negatively charged -COO - At this time, the type B gelatin solution is negatively charged. Due to the deprotonation effect of the amino group in the type B gelatin, -NH +The carboxyl group protonates to form -COOH, which makes gelatin positively charged as the pH value gradually decreases. At the same time, due to the carboxyl groups of aL-guluronic acid and β-D-mannuronic acid in sodium alginate reacting with Na + Ionization makes the molecular chain segments of sodium alginate negatively charged. At this time, gelatin and sodium alginate will induce electrostatic interaction and undergo complex coagulation behavior (coagulation refers to the coagulation of a substance in a solution due to changes in the environment, and complex coagulation refers to the coagulation of two substances in a solution due to interaction).

[0028] Gelatin has both hydrophilic and hydrophobic groups and is surface active, so gelatin solution has good emulsification and foaming properties. First, the sunscreen and gelatin solution are homogenized and emulsified, and the gelatin molecules and the organic solvent containing the sunscreen form an oil / gelatin solution (O / W emulsion). After the organic solvent is removed by rotation, a submicron sunscreen particle dispersion is obtained. Sodium alginate is then added, and the pH value is adjusted to make the gelatin positively charged. Sodium alginate adsorbs gelatin to form spherical microcapsules, and then Ca is added. 2+ It forms an "egg-box structure" by complexing with sodium alginate, solidifying the capsule wall of the microcapsule, improving the compactness of the microcapsule and enhancing the strength of the capsule wall.

[0029] The triazine sunscreen molecule contains an intramolecular hydrogen bond involving a hydroxyl or amino group, which forms a six-membered ring with the N atom. This six-membered ring and the surrounding structure form a conjugated system. The optical band gap of the conjugated system is similar to the ultraviolet light energy in the UVA and UVB range. When the molecule itself absorbs ultraviolet light, the molecular energy increases, the NH bond in the conjugated system breaks, and the structure becomes unstable after the hydrogen bond breaks. It is easy to convert the absorbed ultraviolet light energy into harmless heat energy, fluorescence, phosphorescence and other forms and release it. At the same time, the molecular structure is restored to the original structure, and so on, achieving the effect of absorbing ultraviolet rays. Due to the presence of phenolic hydroxyl groups in bis-ethylhexyloxyphenol methoxyphenyl triazine, the hydrogen bonding effect is extremely strong, so it has a good UVA absorption capacity; while octyl triazone is NH hydrogen bonding, the UVA absorption capacity is weak, but the UVB absorption capacity is excellent. The combination of the two can have excellent UVA and UVB absorption capacity. At the same time, the chemical structures of the two are similar and have good compatibility.

[0030] Among them, the chemical structure of bis-ethylhexyloxyphenol methoxyphenyl triazine sunscreen is as follows:

[0031]

[0032] The chemical structure of octyl triazone sunscreen is as follows:

[0033]

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The present invention selects natural polymer materials to prepare microcapsules by complex coacervation method. The biopolymer is naturally non-toxic, degradable and has good biocompatibility. The sunscreen is compressed to submicron level by solvent volatilization method, which greatly increases the dispersibility in water. Since the sunscreen is hydrophobic, if it is directly coated with natural polymer materials, it can be directly dispersed evenly in water without oil dissolution. By reducing the addition of oily raw materials in sunscreen, the sunscreen feels refreshing on the skin, and overcomes the shortcomings of current high SPF sunscreen such as greasy feeling.

[0036] 2. The triazine sunscreen microcapsules of the present invention are coated with gelatin-sodium alginate to encapsulate the oil-soluble bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone sunscreen agents, which can be well dispersed in water without stratification after long-term storage, and have a good embedding rate for the triazine sunscreen agents.

[0037] 3. The triazine sunscreen microcapsules of the present invention have excellent safety, sunscreen, dispersibility, stability, broad-spectrum ultraviolet protection, and good protection effects on both UVA and UVB. The capsule wall is a natural polymer material and has good biocompatibility.

[0038] 4. The raw materials for the preparation of the present invention exist in large quantities in nature, the production process is simple to operate, and the particle size of the microcapsules can be adjusted by the homogenization speed and the homogenization time to control the particle size distribution, the quality control is simple, the organic solvent used in the preparation process can be recovered and reused by rotary evaporation, the production process does not pollute the environment, and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a standard curve of the bis-ethylhexyloxyphenol methoxyphenyl triazine sunscreen agent and octyl triazone ketone of the present invention dissolved in ethyl acetate respectively;

[0040] Figure 2 The particle size distribution diagram of the particle dispersion in the microcapsule prepared in Examples 7-9;

[0041] Figure 3 are optical microscope images of triazine microcapsules of Example 4 and Example 7;

[0042] Figure 4 is a particle size distribution diagram of the triazine microcapsules of Example 4 and Example 7;

[0043] Figure 5 The dispersion stability of the microcapsules prepared in Example 7;

[0044] Figure 6 is the ultraviolet absorption graph of the triazine sunscreen microcapsules of Example 7;

[0045] Figure 7It is an infrared comparison picture of the triazine sunscreen microcapsules of Example 7, blank microcapsules, bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone sunscreen agent. DETAILED DESCRIPTION

[0046] The content of the present invention is further described below in conjunction with specific examples, but it should not be construed as limiting the present invention. If not specifically indicated, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0047] Example

[0048] 1. Add 1g of gelatin to 100g of deionized water, stir and heat at 40°C to dissolve, and obtain a clear 1% gelatin solution; add 1g of sodium alginate powder to 200g of deionized water, stir and heat at 40°C to dissolve, and obtain a 0.5% sodium alginate solution; prepare different gelatin-sodium alginate solutions according to the mass ratio of gelatin to sodium alginate in Table 1.

[0049] 2. Dissolve 1 g of bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone in a mass ratio of 1: (0.1-0.3) in 5 g of dichloromethane to obtain a yellow clear solution, then add 100 g of 1% gelatin solution and 0.05 g of Tween-80, homogenize and emulsify to obtain an O / W emulsion (mixed color of milky white and light yellow); put the O / W emulsion into a rotary evaporator at 50° C., a negative pressure of -0.4 MPa, and a rotation speed of 50-200 rpm for rotary evaporation for 50-100 min. After the dichloromethane is completely volatilized, collect the organic solvent in the rotary evaporator and wait for reuse to obtain a triazine sunscreen particle dispersion.

[0050] 2. The triazine sunscreen particle dispersion and gelatin-sodium alginate solution are mixed into a 1% gelatin-sodium alginate solution and stirred at 400-600 rpm, the pH value of the system is adjusted to 4.2, and a complex coagulation reaction is carried out for 10 min in a 40° C. water bath with stirring to obtain a gel system, 100 mL of distilled water is added to the gel system for dilution, and then a 3 g / 30 mL calcium chloride aqueous solution is added for cross-linking and curing, and the solution is placed in a water bath at 5-10° C. for 30 min. After the cross-linking is completed, the pH value is adjusted to 5.8-6.5, and the solution is spray-dried or freeze-dried to obtain triazine sunscreen microcapsules.

[0051] Since microcapsules are not 100% encapsulated, the encapsulation rate will change under different conditions. Some microcapsules may be damaged during the encapsulation process due to different process conditions, which may cause the capsule core to come into contact with the outside world during use, causing adverse effects, contact with the human body surface, causing allergies, or penetrating into the human body. The higher the encapsulation rate, the better the conditions for the raw material encapsulation, the less raw material loss, and the less harm caused. Microcapsule encapsulation rate (%) = (m1-m2) / m 1* 100% formula (1), wherein m2 is the total mass of bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone contained in the triazine sunscreen microcapsules, and m1 is the total mass of the sunscreen particle dispersion added in step 2.

[0052] Take 20 mg of triazine sunscreen microcapsule powder and add 10 mL of ethyl acetate, take 0.1 mL of ethyl acetate solution of triazine sunscreen microcapsules, and adjust the volume in a 10 mL constant volume bottle to prepare a 20 mg / L microcapsule-ethyl acetate solution. After washing the sunscreen agent on the surface of the microcapsule with ethyl acetate, the microcapsule solution is filtered with an organic filter membrane to obtain an ethyl acetate clear solution, and then use a double beam ultraviolet spectrophotometer to measure the absorbance A at λ=350nm and λ=307 350nm , A 307nm , compared Figure 1 (b) and Figure 1 The mass m2 of bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone in the microcapsule is obtained by using the standard curve of bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone in (d), and m1 is the total mass of the sunscreen particle dispersion added in step 2 of the embodiment.

[0053] Table 1 Ratios of different raw materials and process conditions in sunscreen microcapsules of Examples 1 to 10 and their embedding rates and dispersion properties

[0054]

[0055]

[0056] Standard testing environment conditions: temperature: (23±2)℃, relative humidity: (50±5)%.

[0057] 1. Particle size test: Malvern Mastersizer 3000 laser diffraction particle size analyzer is used to measure the particle size and particle size distribution of submicron sunscreen particles and sunscreen microcapsules. The dispersed samples are placed in the sample pool equipped with the instrument. The measurement temperature is 25°C, the dispersion system is water, the lower limit of the light shielding is 10%, and the upper limit is 15%. Among them, the refractive index of the sunscreen microcapsules is set to 1.35, and the refractive index of the submicron sunscreen particles is set to 1.56.

[0058] 2. UV absorbance test:

[0059] (1) UV absorption test of aqueous solution: Take a small amount of sunscreen microcapsules and disperse them in a 100-fold mass ratio aqueous solution. Shake it manually until it is completely dispersed. Use a pipette to take 2 mL of the sunscreen microcapsule aqueous solution and place it on a 2 cm x 5 cm slide. Use a UV-visible spectrophotometer to test the UV absorption spectrum of the sunscreen microcapsule aqueous solution.

[0060] (2) Powder UV absorption test: Take an appropriate amount of solid sunscreen microcapsule powder and spread it in the center of the sample dish. Cover the sample dish with dry barium sulfate. After tightening the sample dish, directly use a UV-visible-near-infrared spectrophotometer to test its solid UV absorption spectrum.

[0061] 3. Dispersibility test: Take an appropriate amount of solid sunscreen microcapsule powder and redisperse it back into the water. Observe the sedimentation of the sunscreen microcapsule powder at regular intervals and record it.

[0062] 4. Infrared absorption spectrum test: Take a small amount of sunscreen microcapsule solid powder and control group powder, add KBr to grind, press into tablets, and place them directly on the sample rack to measure the infrared absorption spectrum. The FTIR scanning range is set to 500~4000cm -1 , resolution 4cm -1 .

[0063] Table 1 shows the embedding rate and dispersibility of triazine sunscreen microcapsules with different raw material ratios and process conditions in Examples 1 to 10. As can be seen from Table 1, when the mass ratio of gelatin to sodium alginate is 1:1, the embedding rate of bis-ethylhexyloxyphenol methoxyphenyl triazine microcapsules is up to 88.63%, and when the sodium alginate content is too high, the sunscreen microcapsules will stick together, the dispersibility is extremely poor, and they are easy to settle. When the mass ratio of gelatin to sodium alginate is 5:1, the homogenization speed is 16000 rpm, the homogenization time is 10min, and the wall-core mass ratio is 1:1 (the wall is gelatin / sodium alginate, and the core is bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone), the embedding rate of the obtained triazine sunscreen microcapsules is up to 85.68%, and the dispersibility is the best. With the increase of homogenization time and homogenization speed, the particle size of the sunscreen microcapsules is gradually getting smaller, and the smaller the particle size, the better the dispersibility. Therefore, the optimal conditions were a mass ratio of gelatin to sodium alginate of 5:1, a wall-core mass ratio of 1:1, a homogenization time of 10 min, and a homogenization speed of 16,000 rpm.

[0064] Figure 1The standard curves of bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone of the present invention; wherein, (a) is the ultraviolet absorption spectrum of 10-30 mg / L bis-ethylhexyloxyphenol methoxyphenyl triazine, (b) is the standard curve of bis-ethylhexyloxyphenol methoxyphenyl triazine, (c) is the ultraviolet absorption spectrum of 10-30 mg / L octyl triazone, and (d) is the standard curve of octyl triazone. (e) is the ultraviolet absorption spectrum of bis-ethylhexyloxyphenol methoxyphenyl triazine, octyl triazone, and bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone. From Figure 1 It can be seen that bis-ethylhexyloxyphenol methoxyphenyl triazine has a certain absorption intensity in the wavelength range of 300-375nm, but the absorption intensity at around 300nm is not as good as that of octyl triazone. When bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone are compounded, the absorption intensity of UVA and UVB is stronger than when the two are used alone. This is because the chelate ring formed by the hydrogen bonding effect of bis-ethylhexyloxyphenol methoxyphenyl triazine is in contact with octyl triazone with a similar chemical structure. The NH bond in octyl triazone participates in enhancing the hydrogen bonding effect of the former, thereby enhancing the ring-opening energy of the chelate ring, so that the absorption intensity of UVA and UVB of the compound of bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone increases, and the sunscreen effect is enhanced, indicating that the synergistic effect of the compound of the two makes the sunscreen microcapsules have a better broad-spectrum protection effect.

[0065] Figure 2 is the particle size distribution of the particle dispersion in the triazine sunscreen capsules of Examples 7-9. Figure 2 It can be seen that the particle size of the sunscreen particle dispersion prepared by the homogenization conditions of Examples 7-9 presents a normal distribution, and the distribution curve is single and narrow. Under the homogenization conditions, the particle size of the triazine sunscreen particle dispersion is 400nm-4um. Since the homogenization time of Examples 1-6 is short and slow, the particle size of the formed emulsion droplets is larger, so the precipitated particles are also large, and the particle size of the formed microcapsules is also increased. Therefore, the homogenization conditions will affect the particle size of the sunscreen particle dispersion, thereby affecting the particle size of the microcapsules.

[0066] Figure 3 Figure 2 is an optical micrograph of the triazine sunscreen microcapsules of Examples 4 and 7. Figure 3 It can be seen that the triazine sunscreen microcapsules of Example 4 have a core-shell structure, and the triazine sunscreen is successfully wrapped in the microcapsule wall, thereby avoiding contact with the outside world and avoiding direct contact between the triazine sunscreen and the human body surface. The triazine sunscreen microcapsules are attached to the human skin surface to form a protective effect. The capsule wall of the triazine sunscreen microcapsules of Example 4 is translucent, so the triazine sunscreen microcapsules in Examples 4 and 7 will increase the refraction and diffusion of ultraviolet rays between the microcapsule core material and the capsule cavity, thereby improving the sunscreen performance.

[0067] Figure 4 Figure 4 is a particle size distribution diagram of the triazine sunscreen microcapsules of Example 4 and Example 7. Figure 4 It can be seen that the average particle size of the triazine sunscreen microcapsules in Example 4 is 56 um, and the average particle size of the triazine sunscreen microcapsules in Example 7 is 5.6 um, which means that by controlling different parameters of homogenization emulsification, triazine sunscreen microcapsules with different particle sizes (1-100 um) can be prepared, thereby achieving the regulation of the particle size of the microcapsules.

[0068] Figure 5 The triazine sunscreen microcapsules of Example 7 are dispersed stably in water, wherein (a) is the sedimentation effect of the sunscreen microcapsules of Example 7 in water within 24 hours, and (b) is the comparison of the dispersion effect of the sunscreen microcapsules of Example 7 and bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone in water at a mass ratio of 0.75:0.25 without microencapsulation. Figure 5 As can be seen in (a), the triazine sunscreen microcapsules did not undergo any sedimentation in the aqueous solution for 4 hours, and the sunscreen microcapsules slightly precipitated after 8 hours, and the solution was slightly less turbid. After 12 hours, obvious sedimentation was found, and after 24 hours, the solution became clear. This shows that the smaller the particle size of the microcapsules, the longer the sedimentation time, and the more conducive to dispersion in water. Figure 5 (b) It can be seen that the triazine sunscreen microcapsules can achieve a good dispersion effect in deionized water after stirring for 1 minute, while the bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone ketone with a mass ratio of 0.75:0.25 that have not been microencapsulated cannot be dispersed on the water surface even after being ultrasonicated in a 100W ultrasonic microwave cleaning machine for 5 minutes, indicating that microencapsulation of bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone will give them a good dispersion effect in water.

[0069] Figure 6 The ultraviolet absorption diagram of the triazine sunscreen microcapsule solution and powder of Example 7, wherein (a) is the triazine sunscreen microcapsule of Example 7 (bis-ethylhexyloxyphenol methoxyphenyl triazine:octyl triazone ketone with a mass ratio of 0.75:0.25) dissolved in C 12～15 Alkyl benzoate (TS-T150), triazine sunscreen microcapsule aqueous solution and blank microcapsule aqueous solution. (b) is the triazine sunscreen microcapsule powder of Example 7, and blank microcapsule powder. Figure 6 It can be seen that the aqueous solution of the triazine sunscreen microcapsules of Example 7 and C 12～15 The alkyl benzoate solution has an ultraviolet absorption peak in the wavelength range of 300-400nm. The ultraviolet absorption effect of the aqueous solution of triazine sunscreen microcapsules is better than that of the triazine sunscreen microcapsules dissolved in C 12～15The blank microcapsules (Example 10) do not have the UV absorption effect in alkyl benzoates, but the UV absorption capacity of the triazine sunscreen microcapsules within a wavelength of 200 to 400 nm is even better than that of the triazine sunscreen agents that have not been microencapsulated, proving that the triazine sunscreen microcapsules have successfully encapsulated the triazine sunscreen agents and enhanced their UV absorption capacity.

[0070] Figure 7 This is a comparison chart of infrared analysis of the triazine sunscreen microcapsules, blank microcapsules, bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone sunscreen agents that are not microencapsulated in Example 7. Figure 7 It can be seen that the characteristic peak of bis-ethylhexyloxyphenol methoxyphenyl triazine is 3500cm -1 Phenolic hydroxyl stretching vibration, 1371 cm -1 Phenolic hydroxyl in-plane bending vibration, 1109 cm -1 Ar-OC ether bond stretching vibration, 1270 cm -1 The stretching vibration of the CN carbon-nitrogen single bond is 1628 cm -1 The C=N double bond stretching vibration, at the same time, octyl triazone ketone at 1720cm -1 The characteristic peak of ester C=O stretching vibration was found. The triazine sunscreen microcapsules have a peak at 1270 cm -1 There is a similar strong absorption peak of CN single bond stretching vibration at 1628cm -1 The characteristic peak of C=N double bond stretching vibration was found at 1109cm -1 There is also a stretching vibration absorption peak of the Ar-OC ether bond of bis-ethylhexyloxyphenol methoxyphenyl triazine (the sunscreen agent TS in the figure is the abbreviation of bis-ethylhexyloxyphenol methoxyphenyl triazine), 1720 cm -1 There is also C=O stretching vibration of the ester group of octyl triazone, while the infrared spectrum of the blank microcapsules has no obvious sharp characteristic absorption peaks at these three positions, proving that the triazine sunscreen microcapsules contain bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone, and this method can effectively encapsulate the sunscreen agent.

[0071] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing triazine sunscreen microcapsules, comprising the following steps: S1. Dissolve sunscreen bis-ethylhexyloxyphenol methoxyphenyl triazine and octyl triazone in an organic solvent, add an emulsifier and 1-10wt% gelatin solution for homogenization and emulsification to obtain an emulsified system; the mass ratio of bis-ethylhexyloxyphenol methoxyphenyl triazine to octyl triazone in the sunscreen is 1:(0.1-0.3); the mass ratio of the sunscreen to the organic solvent is 1:(2-5); the organic solvent is dichloromethane, petroleum ether, n-hexane or ethyl acetate; the emulsifier is one or more of Span 20, Tween-80 or potassium hexadecyl phosphate, and the emulsifier is 0.7-1.3wt% of the organic solvent; the gelatin is type B gelatin; S2. The emulsified system is subjected to rotary evaporation at 40-60°C and a negative pressure of -0.2-0.5 MPa to obtain a submicron sunscreen particle dispersion; S3. Mix the gelatin solution, sodium alginate solution and submicron sunscreen particle dispersion, adjust the pH value of the mixed system to 4.0-4.5, and perform complex coagulation at 40-50°C to obtain a gel system; the concentration of the gelatin solution is 0.5-1wt%, and the concentration of the sodium alginate solution is 0.1-1wt%; the mass ratio of the gelatin solution, sodium alginate solution and submicron sunscreen particle dispersion is (1-10):1:(1-2); the gelatin solution and sodium alginate solution are 0.5-1wt% of the total mass of the gelatin solution, sodium alginate solution and submicron sunscreen particle dispersion; S4. Add calcium chloride solution to the gel system for cross-linking at 5-10° C. for 30-60 min, wherein the calcium chloride in the calcium chloride solution is 0.1-0.5 wt % of the gel system, and then adjust the pH value of the system to 6.0-6.5, dry, and obtain triazine sunscreen microcapsules.

2. The method for preparing triazine sunscreen microcapsules according to claim 1, characterized in that: The homogenization and emulsification rate in step S1 is 6000-18000 rpm, and the homogenization and emulsification time is 3-10 min.

3. The method for preparing triazine sunscreen microcapsules according to claim 1, characterized in that: The particle size of the submicron sunscreen particle dispersion in step S2 is 400nm~4µm.

4. The method for preparing triazine sunscreen microcapsules according to claim 1, characterized in that: The rotation speed of the rotary evaporation in step S2 is 50-200 rpm, and the time of the rotary evaporation is 50-100 min.

5. The method for preparing triazine sunscreen microcapsules according to claim 1, characterized in that: The drying in step S4 is freeze drying or spray drying.

6. A triazine sunscreen microcapsule, characterized in that: The triazine sunscreen microcapsules are prepared by the method described in any one of claims 1 to 5.

7. Use of the triazine sunscreen microcapsules according to claim 6 in the field of fine chemicals.

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