Micro-jet physical sunscreen powder slurry as well as preparation method and application thereof

Abstract

The invention relates to the technical field of cosmetics, in particular to micro-jet physical sunscreen powder slurry as well as a preparation method and application thereof. The sunscreen powder slurry comprises zinc oxide powder slurry and titanium dioxide powder slurry; the zinc oxide powder slurry is prepared from the following raw materials: nano zinc oxide, an emollient, a first emulsifier and a first adhesive; the titanium dioxide powder slurry is prepared from the following raw materials: nano titanium dioxide, an emollient, a second emulsifier, a second adhesive and a third adhesive; the zinc oxide powder slurry and the titanium dioxide powder slurry are respectively subjected to microjet treatment. Nano-zinc oxide and nano-titanium dioxide are selected as core sun-screening agents, the nano-zinc oxide and the nano-titanium dioxide are subjected to refining treatment through the advanced micro-jet technology, fine and uniform sun-screening powder slurry is obtained, the sun-screening index of a sun-screening product can be remarkably increased, and the sun-screening powder slurry is small in particle size, high in light transmittance, high in light aging resistance and good in sun-screening effect. The problems of non-uniform particle size distribution, whitening after smearing, low sunscreen efficiency and the like of a physical sunscreen agent are solved, and the application prospect is wide.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cosmetic technology, in particular to a microfluidic physical sunscreen powder, a preparation method and application thereof. BACKGROUND

[0002] With the continuous rise of global ultraviolet radiation intensity due to environmental changes, skin photodamage problems are becoming increasingly serious, and the protection efficiency and safety of sunscreen products have become the core focus of industry research and development. Traditional sunscreen technology mainly relies on two paths of chemical sunscreen agents and physical sunscreen agents, but both have significant technical bottlenecks, which restrict the safe use and promotion of sunscreen products. Chemical sunscreen agents reduce the risk of skin damage by absorbing ultraviolet rays and converting them into heat energy, thereby reducing the risk of skin damage. However, its molecular structure often contains benzene rings, nitro groups and other highly reactive groups, which are prone to photochemical reactions under ultraviolet radiation, generating harmful substances such as free radicals and active oxygen. Long-term use can cause damage to the skin barrier function, induce allergies, inflammation, and even increase the risk of skin cancer, and can also interfere with hormone balance, posing a potential threat to the health of children and sensitive groups. Although the industry has reduced toxicity through structural modification, the light stability and biological safety of chemical sunscreen agents are still difficult to balance, making it difficult to popularize their use. Physical sunscreen agents achieve protection by reflecting and scattering ultraviolet rays, with the advantages of high stability and safety. However, their protection efficiency is limited by particle characteristics and dispersion technology: on the one hand, traditional physical sunscreen agents have large particle sizes (usually >100 nm), which have low reflection efficiency for the UVA band (320-400 nm), making it difficult to improve the SPF value; on the other hand, particles are prone to aggregation due to van der Waals forces, forming uneven sunscreen film layers and creating ultraviolet penetration gaps. At the same time, the high concentration of physical sunscreen agents can result in thick and white product texture, severely affecting user experience and making it difficult to meet the needs of consumers.

[0003] Chinese patent CN117159398B discloses a superfluid composite sunscreen agent and a water-in-oil-in-oil triple sunscreen cream, which solves the problems of pore blockage, greasy feeling and side effects of existing sunscreen agents in cosmetics by using a specific ratio of non-ionic surfactant combined with sunscreen agents, and combining the water-in-oil-in-oil triple sunscreen cream process, achieving high-efficiency, stable and safe sunscreen effect. Chinese patent CN116602877B discloses an easy-to-clean sunscreen product and a preparation method thereof, which solves the problem of difficult cleaning of waterproof sunscreen cream by using a combination of water-in-oil emulsifiers, film formers and emollients in the sunscreen product, achieving waterproof and sweat-resistant effects and easy-to-clean characteristics. However, these existing technologies do not solve the above technical problems, and the SPF value and use experience of sunscreen agents still need to be improved.

[0004] In this context, the industry urgently needs to develop a sunscreen product with high SPF value and biosafety, while meeting the multiple needs of consumers for sunscreen efficacy, use experience and safety. SUMMARY

[0005] To solve the above technical problems, the first aspect of the present application provides a microfluidic physical sunscreen powder slurry, the sunscreen powder slurry comprising a zinc oxide powder slurry and a titanium dioxide powder slurry.

[0006] Optionally, the preparation raw materials of the zinc oxide powder slurry comprise, by weight, 5-25 parts of nano zinc oxide, 5-15 parts of an emollient, 0.5-5 parts of a first emulsifier, and 0.1-1 parts of a first binder; and the preparation raw materials of the titanium dioxide powder slurry comprise 5-25 parts of nano titanium dioxide, 8-20 parts of an emollient, 0.1-2 parts of a second emulsifier, 0.1-2 parts of a second binder, and 0.1-1 parts of a third binder. Optionally, the zinc oxide powder slurry and the titanium dioxide powder slurry are subjected to microfluidic treatment respectively.

[0007] Optionally, the microfluidic treatment is performed under the following conditions: a microfluidic channel pore size of 100-300 nm, and a microfluidic pressure of 150-200 MPa.

[0008] Optionally, the nano zinc oxide is NAOCOS ZS1004B or MZX-508OTS.

[0009] Optionally, the microfluidic treatment is performed under the following conditions: a microfluidic channel pore size of 100-300 nm, and a microfluidic pressure of 150-200 MPa.

[0010] Optionally, the nano zinc oxide is NAOCOS ZS1004B or MZX-508OTS.

[0011] Optionally, the nano titanium dioxide is Dexian® NM-H26 or MICRO TITANIUM DIOXIDE MT-100TV.

[0012] Optionally, the emollient is polydimethylsiloxane.

[0013] Optionally, the first emulsifier and the second emulsifier are both polyglyceryl-3 polydimethylsiloxyethyl dimethicone.

[0014] Optionally, the preparation raw materials of the titanium dioxide powder slurry further comprise 0.1-2 parts of a third emulsifier. Optionally, the third emulsifier is PEG-9 polydimethylsiloxyethyl dimethicone.

[0015] The second aspect of the present application provides a preparation method of the sunscreen powder slurry as described above, and the preparation steps of the sunscreen powder slurry comprise: The nano zinc oxide, the emollient, the first emulsifier and the first binder are mixed, homogenized and filtered, and then subjected to micro-jet treatment to obtain the zinc oxide powder slurry. The nano titanium dioxide, the emollient, the second emulsifier, the second binder and the third binder are mixed, homogenized and filtered, and then subjected to micro-jet treatment to obtain the titanium dioxide powder slurry.

[0016] The third aspect of the present application provides an application of the micro-jet physical sunscreen powder slurry as described above, and the sunscreen powder slurry is applied to the preparation of a sunscreen product.

[0017] Optionally, the sunscreen product is a sunscreen cream, and the preparation raw materials of the sunscreen cream comprise the sunscreen powder slurry, a humectant, a thickening agent, an antioxidant, an adsorbent, an emollient, a fourth emulsifier and a solvent. Optionally, the addition amount of the sunscreen powder slurry in the sunscreen cream is 20-60wt%.

[0018] Beneficial effects: The present application provides a micro-jet physical sunscreen powder slurry, a preparation method and an application thereof, and has the following advantages: (1) The present application selects nano zinc oxide and nano titanium dioxide as core sunscreen agents, and uses advanced micro-jet technology to finely process the two, which can significantly improve the sun protection factor (SPF) of the sunscreen product and build an efficient and stable ultraviolet protection barrier.

[0019] (2) The present application preferably selects nano zinc oxide as NAOCOS ZS1004B (Changzhou Naoer) or MZX-508OTS (Empire Chemical Industry), and nano titanium dioxide as Dexian®NM-H26 (Guangzhou Desen) or MICRO TITANIUM DIOXIDE MT-100TV (Empire Chemical Industry), which can improve the SPF value of the sunscreen product to above 50 and the PFA value to above 10.

[0020] (3) The present application respectively compounding nano titanium dioxide and nano zinc oxide with specific emulsifiers, emollients, binders and the like, and then processing them through a micro-jet device, can prepare fine and uniform zinc oxide powder slurry and titanium dioxide powder slurry, which on the one hand solves the problem of too thick and high viscosity of the material liquid when mixing titanium dioxide and zinc oxide and then performing micro-jet treatment, and on the other hand solves the problem of uneven particle size distribution and whitening of the physical sunscreen agent.

[0021] (4) Preferably, the microfluidization treatment is carried out under the following conditions: a microfluidization channel pore size of 100-300 nm and a microfluidization pressure of 150-200 MPa. The process conditions can fully exert the crushing and homogenization effect on the specific sunscreen powder slurry raw material, so that the particle size of the sunscreen product (e.g., sunscreen cream) prepared finally can reach below 8 pm, and the light transmittance can reach above 91%.

[0022] (5) In the present application, nano-zinc oxide and nano-titanium dioxide are used as core sunscreen agents to prepare a powder slurry, and are combined with emollients, humectants, antioxidants, emulsifiers, adsorbents, thickening agents, adhesives, solvents and other auxiliary agents to design a specific sunscreen product formula system, thereby further optimizing the product performance and improving the sunscreen performance and use experience of the product.

[0023] (6) The present application not only realizes the efficient preparation of sunscreen powder slurry and sunscreen products, but also solves the problems of uneven particle size distribution, whitening after application, insufficient sunscreen efficiency and other use problems of physical sunscreen agents (such as nano-zinc oxide or nano-titanium dioxide). The sunscreen index of the obtained product is significantly improved, the particle size is smaller and the distribution is narrower, and the light transmittance is higher. The problems of whitening after application and the like are effectively solved, and the use experience is optimized. After use, it has a "light and breathable feeling", and there is no sticky, muddy, heavy and other discomfort.

[0024] (7) The sunscreen product of the present application is added with specific zinc oxide powder slurry and titanium dioxide powder slurry, which significantly improves the anti-photoaging property of the sunscreen product. The sunscreen product can protect the skin from ultraviolet (UVA / UVB) and visible light, infrared light and other light radiation damage through multiple mechanisms, thereby delaying the skin photoaging process. After use, it can reduce DNA breakage, collagen degradation, pigmentation and inflammatory response caused by light damage, thereby preventing wrinkles, laxity, pigmentation and other signs of aging.

[0025] (8) The raw materials of the present application are easy to obtain, and the preparation process is simple. The sunscreen product with high content of sunscreen agent can be prepared, and the technology has strong practicality. Batch production of high-quality sunscreen powder slurry (raw material end) and sunscreen products can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Microscopic observation results of the sunscreen cream of Example 1 (magnification 500); Figure 2 Microscopic observation results of the sunscreen cream of Example 2 (magnification 500); Figure 3 Microscopic observation results of the sunscreen cream of Comparative Example 1 (magnification 500); Figure 4 Anti-photoaging test results. DETAILED DESCRIPTION

[0027] In view of the poor safety of the existing chemical sunscreen agents, the limited sunscreen effect of the physical sunscreen agents, and the technical problems of poor particle size uniformity, easy fake white and the like, the present application provides a micro-fluid physical sunscreen powder slurry and a sunscreen product, which can improve the sunscreen effect of the sunscreen product while ensuring safety, and has small particle size, high light transmittance, delicate texture and no "fake white" when being applied, and good use experience.

[0028] The present application provides a micro-fluid physical sunscreen powder slurry in the first aspect, wherein the sunscreen powder slurry comprises a zinc oxide powder slurry and a titanium dioxide powder slurry.

[0029] In some embodiments, the preparation raw materials of the zinc oxide powder slurry comprise 5-25 parts by weight of nano-zinc oxide, 5-15 parts by weight of an emollient, 0.5-5 parts by weight of a first emulsifier and 0.1-1 parts by weight of a first binder; and the preparation raw materials of the titanium dioxide powder slurry comprise 5-25 parts by weight of nano-titanium dioxide, 8-20 parts by weight of an emollient, 0.1-2 parts by weight of a second emulsifier, 0.1-2 parts by weight of a second binder and 0.1-1 parts by weight of a third binder.

[0030] Optionally, the nano-zinc oxide and the nano-titanium dioxide are subjected to micro-fluid treatment respectively.

[0031] Optionally, the micro-fluid treatment is performed under the following conditions: a micro-fluid channel pore size of 100-300 nm and a micro-fluid pressure of 150-200 MPa.

[0032] Further optionally, the micro-fluid treatment is performed under the following conditions: a micro-fluid channel pore size of 125-275 nm and a micro-fluid pressure of 160-180 MPa.

[0033] The applicant found that although the microfluidization technology can crush, disperse and homogenize solid particles into extremely fine nanoparticles, if the nanoparticles of zinc oxide and the nanoparticles of titanium dioxide are mixed and then subjected to microfluidization operation, the liquid material is too thick and the viscosity is too high, the machine is difficult to work efficiently, and even faults such as blockage are prone to occur, which also affects the product quality. In the application, the nanoparticles of titanium dioxide and the nanoparticles of zinc oxide are respectively compounded with specific emulsifiers, emollients and adhesives, and then subjected to microfluidization treatment. In the microfluidization treatment process, the materials pass through extremely fine nozzles and collide with each other under high pressure, so that extremely high shearing force, impact force and cavitation effect can be generated, and fine and uniform zinc oxide slurry and titanium dioxide slurry can be prepared. Further, the physical sunscreen product can be prepared, which can not only realize efficient preparation of sunscreen slurry, but also solve the problems of uneven particle size distribution, whitening after smearing, insufficient sunscreen efficiency and other use problems of the current physical sunscreen, reduce the particle size of the product and improve the light transmittance. Further, the microfluidization treatment conditions are as follows: the microfluidization channel aperture is 100-300 nm, and the microfluidization pressure is 150-200 MPa. The process conditions can fully play the crushing and homogenizing effect on specific sunscreen slurry raw materials, so that the particle size of the sunscreen product (such as sunscreen cream) prepared finally can reach below 8 μm, the light transmittance can reach above 91%, and the anti-aging property is excellent.

[0034] Optionally, the median particle size of the nanoparticles of zinc oxide is 30-500 nm.

[0035] Optionally, the surface of the nanoparticles of zinc oxide contains a coating, and the coating material is triethoxyl octyl silane.

[0036] Optionally, the median particle size of the nanoparticles of titanium dioxide is 10-150 nm.

[0037] Optionally, the surface of the nanoparticles of titanium dioxide contains a coating, and the coating material is a combination of one or more of silica, aluminum hydroxide, stearic acid, triethoxyl octyl silane, polydimethylsiloxane, aluminum oxide and aluminum stearate.

[0038] In order to improve the sun protection factor of the sunscreen product, in some embodiments, the nanoparticles of zinc oxide are NAOCOSZS1004B (Changzhou Naoer) or MZX-508OTS (Imperial Chemical).

[0039] In order to improve the sun protection factor of the sunscreen product, in some embodiments, the nanoparticles of titanium dioxide are Dexian®NM-H26 (Guangzhou Desen) or MICRO TITANIUM DIOXIDE MT-100TV (Imperial Chemical).

[0040] The inventors of the present application have tried zinc oxide, titanium dioxide raw materials from many manufacturers, and finally unexpectedly found that the preferred nano zinc oxide is NAOCOS ZS1004B (Changzhou Naoyue) or MZX-508OTS (Imperial Chemical), and the preferred nano titanium dioxide is Dexian NM-H26 (Guangzhou Desen) or MICRO TITANIUM DIOXIDE MT-100TV (Imperial Chemical), which can increase the SPF value of the sunscreen product to above 50 and the PFA value to above 10; it is speculated that the nano zinc oxide and nano titanium dioxide of a specific particle size and coating have strong adaptability, can be fully and uniformly dispersed in the formula system of the sunscreen powder slurry, and can prepare a fine and uniform sunscreen powder slurry, so as to realize the construction of a protective barrier, avoid protective loopholes caused by uneven distribution, and effectively improve the sun protection factor of the product; and the use of zinc oxide and titanium dioxide raw materials from other sources cannot achieve similar excellent effects.

[0041] In some embodiments, the emollient can include, but is not limited to, dimethicone, caprylic / capric triglyceride, isopropyl palmitate, isopropyl myristate, jojoba oil, cetyl alcohol, etc., and dimethicone can be selected.

[0042] In some embodiments, the preparation raw material of the titanium dioxide slurry further includes a third emulsifier 0.1-2 parts.

[0043] The first emulsifier, the second emulsifier, and the third emulsifier can include, but are not limited to, PEG-9 dimethicone copolyol, polyglyceryl-3 polydimethylsiloxyethyl dimethicone, polyglyceryl-4 isostearate, polyglyceryl-10 myristate, sodium cocoyl glutamate, and disodium lauroyl glutamate, etc.; optionally, the first emulsifier and the second emulsifier are polyglyceryl-3 polydimethylsiloxyethyl dimethicone; and the third emulsifier is PEG-9 dimethicone copolyol.

[0044] Further optionally, the addition amount ratio of the first emulsifier, the second emulsifier, and the third emulsifier is (0.5-2):(0.1-1):(0.2-1.5); and more further optionally, 1.25:0.44:0.88.

[0045] In some embodiments, the first binder, the second binder, and the third binder can include, but are not limited to, aluminum hydroxide, triethoxysilane, stearic acid, and phenyl trimethicone, etc.; optionally, the first binder is triethoxysilane; the second binder is aluminum hydroxide; and the third binder is stearic acid.

[0046] Optionally, the mass ratio of the triethoxyl octyl silane, aluminum hydroxide and stearic acid is (0.1-1):(0.1-2):(0.1-1); further optionally (0.6-0.8):(1-1.5):(0.2-6).

[0047] The second aspect of the present application provides a preparation method of a microfluidic physical sunscreen powder slurry, the preparation steps of the sunscreen powder slurry comprising: Mixing the nano zinc oxide, the emollient, the first emulsifier and the first binder, homogenizing and filtering, and then performing microfluidic treatment to obtain a zinc oxide powder slurry; Mixing the nano titanium dioxide, the emollient, the second emulsifier, the second binder and the third binder, homogenizing and filtering, and then performing microfluidic treatment to obtain a titanium dioxide powder slurry.

[0048] The third aspect of the present application provides an application of a microfluidic physical sunscreen powder slurry; the sunscreen powder slurry is applied to the preparation of a sunscreen product, which can include sunscreen cream, sunscreen milk, sunscreen spray or sunscreen gel.

[0049] In some embodiments, the sunscreen product is sunscreen milk; the preparation raw materials of the sunscreen milk include: sunscreen powder slurry, humectant, thickening agent, antioxidant, adsorbent, emollient, fourth emulsifier and solvent.

[0050] Optionally, the addition amount of the sunscreen powder slurry in the sunscreen milk is 20-60wt%; further optionally 40-50%.

[0051] Optionally, the preparation raw materials of the sunscreen milk include, by mass percentage: sunscreen powder slurry 40-50%, humectant 2-15%, thickening agent 0.1-2%, antioxidant 0.1-0.6%, adsorbent 0.5-5%, emollient 5-15%, fourth emulsifier 1-5%, and solvent to make up to 100%.

[0052] Further optionally, the preparation raw materials of the sunscreen milk include, by mass percentage: sunscreen powder slurry 45.6692%, humectant 8.7%, thickening agent 0.9%, antioxidant 0.5%, adsorbent 2%, emollient 11.7308%, fourth emulsifier 2%, and solvent to make up to 100%.

[0053] In some embodiments, the humectant can include, but is not limited to, butylene glycol, dipropylene glycol, hexylene glycol, ethoxydiglycol, glycerin, sorbitol, stearyl alcohol, 1,3-butanediol, dipropylene glycol, 1,2-hexanediol, ethoxydiglycol, at least one of the above; further, 1,3-butanediol, dipropylene glycol, 1,2-hexanediol, and ethoxydiglycol; further, the mass ratio of 1,3-butanediol, dipropylene glycol, 1,2-hexanediol, and ethoxydiglycol is (1-10):(0.5-10):(0.1-1):(0.1-1); further, the mass ratio of 1,3-butanediol, dipropylene glycol, 1,2-hexanediol, and ethoxydiglycol is (5-10):(0.5-2):(0.1-1):(0.1-0.5); and most preferably, 7:1.1:0.4:0.2.

[0054] In some embodiments, the antioxidant can include, but is not limited to, 4-hydroxyacetophenone, methyl paraben, propyl paraben, phenoxyethanol, sodium benzoate, and 4-hydroxyacetophenone.

[0055] In some embodiments, the adsorbent can include, but is not limited to, polymethylsilsesquioxane, polyethylsilsesquioxane, polyphenylsilsesquioxane, dimethicone / vinyl dimethicone crosspolymer microspheres, octamethylcyclotetrasiloxane modified microspheres, and polymethylsilsesquioxane.

[0056] In some embodiments, the thickening agent can include, but is not limited to, sodium chloride, potassium chloride, disteardimonium hectorite, carbomer, xanthan gum, sodium polyacrylate, hydroxyethyl cellulose, sodium carboxymethyl cellulose, sodium chloride, and disteardimonium hectorite; further, the sodium chloride is added in an amount of 0.1-2%, and the disteardimonium hectorite is added in an amount of 0.1-1%.

[0057] In some embodiments, the fourth emulsifier can include, but is not limited to, PEG-9 dimethicone crosspolymer, polyglyceryl-3 dimethicone crosspolymer, polyglyceryl-4 isostearate, polyglyceryl-10 myristate, sodium cocoyl glutamate, and disodium lauroyl glutamate; and preferably, the fourth emulsifier is PEG-9 dimethicone crosspolymer.

[0058] The solvent is not particularly limited in the present application, and any solvent capable of achieving the purpose of dissolution can be used, such as water.

[0059] Optionally, the sunscreen cream has an SPF value of ≥50 and a PFA value of ≥16.

[0060] Optionally, the sunscreen cream has a D 90Particle size < 8 μm, light transmittance ≥ 91%.

[0061] In some embodiments, the preparation step of the sunscreen cream comprises: mixing the preparation raw materials, homogenizing uniformly to obtain the sunscreen cream.

[0062] Unless otherwise specified, the raw materials, equipment, and other consumables used in the present application are commercially available. Some raw material source information in the following examples is as follows: In some embodiments, the nano-zinc oxide is sourced from Changzhou Naoyu New Material Technology Co., Ltd., with model number NAOCOS ZS1004B; the product has a median particle size (D50) of 477 nm, and the surface contains a triethoxyl octyl silane coating.

[0063] In some embodiments, the nano-zinc oxide is sourced from Imperial Chemicals, with model number MZX-508OTS; the product has a median particle size (D50) of 36 nm, and the surface contains a triethoxyl octyl silane coating.

[0064] In some embodiments, the nano-zinc oxide is sourced from DSM, with model number PARSOL ZX; the product has a median particle size (D50) of 90-130 nm, and the surface contains a triethoxyl octyl silane coating.

[0065] In some embodiments, the nano-zinc oxide is sourced from BASF, with model number Z-COTE HP1; the product has a median particle size (D50) of 80 nm, and the surface contains a triethoxyl octyl silane coating.

[0066] In some embodiments, the nano-titanium dioxide is sourced from Guangzhou Desen Chemical Co., Ltd., with model number Dexian NM-H26; the product has an original particle size (D50) of 10-20 nm, and the surface contains a coating of stearic acid, aluminum hydroxide, and polydimethylsiloxane.

[0067] In some embodiments, the nano-titanium dioxide is sourced from Imperial Chemicals, with model number Dexian NM-H26; the product has a median particle size (D50) of 130 nm, and the surface contains a coating of stearic acid and aluminum hydroxide.

[0068] In some embodiments, the nano-titanium dioxide is sourced from DSM, with model number PARSOL TX; the product has a median particle size (D50) of 27 nm (TEM), and the surface contains a coating of silica and polydimethylsiloxane.

[0069] In some embodiments, the nano-titanium dioxide is sourced from CRODA, with model number Solaveil TMCTP1; the median particle size (D50) of the product is 45 nm, and the surface contains an alumina, aluminum stearate treated coating.

[0070] Dimethicone: Originated from Shin-Etsu, Japan.

[0071] PEG-9 Dimethicone Ethyl Dimethicone: Originated from Shin-Etsu, Japan.

[0072] Methylphenylpolysiloxane: Originated from Momentive.

[0073] Polyglyceryl-3 Polydimethylsiloxyethyl Dimethicone: Originated from Shin-Etsu, Japan.

[0074] Embodiment Embodiment 1 The present embodiment provides a microfluidic physical sunscreen powder slurry, a preparation method and application thereof.

[0075] The sunscreen powder slurry comprises a zinc oxide powder slurry and a titanium dioxide powder slurry; the preparation raw materials of the zinc oxide powder slurry comprise 14.25 parts of nano zinc oxide, 8 parts of an emollient (dimethicone), 1.25 parts of a first emulsifier (polyglyceryl-3 polydimethylsiloxyethyl dimethicone), and 0.75 parts of a first binder (triethoxyl octyl silane) by weight; the preparation raw materials of the titanium dioxide powder slurry comprise 8.184 parts of nano titanium dioxide, 10.12 parts of an emollient (dimethicone), 0.44 parts of a second emulsifier (polyglyceryl-3 polydimethylsiloxyethyl dimethicone), 1.2144 parts of a second binder (aluminum hydroxide), and 0.5808 parts of a third binder (stearic acid).

[0076] The nano zinc oxide in the present embodiment is originated from Changzhou Naonuo New Material Technology Co., Ltd., and the model is NAOCOSZS1004B; the nano titanium dioxide is originated from Guangzhou Desen Chemical Co., Ltd., and the model is Dexian®NM-H26.

[0077] The preparation steps of the sunscreen powder slurry comprise: The preparation raw materials (nano zinc oxide, emollient, first emulsifier, and first binder) of the zinc oxide powder slurry are mixed in a 1# beaker, the materials are homogenized for 4±1 min until the materials are uniform, filtered using a 200-mesh filter cloth, and then the filtered materials are transferred to a microfluidic device for microfluidic treatment twice (microfluidic conditions: microfluidic channel pore size 200±75 nm, microfluidic pressure 170 MPa) to obtain the zinc oxide powder slurry; The preparation raw materials of the titanium dioxide powder slurry (nanometer titanium dioxide, emollient, second emulsifier, second binder and third binder) were mixed in a 2# beaker, the materials were homogenized for 4±1 min, filtered using a 200 mesh filter cloth, and then the filtered materials were transferred to a microfluidic device for microfluidic treatment twice (microfluidic conditions: microfluidic channel pore size 200±75 nm, microfluidic pressure 170 MPa) to obtain the titanium dioxide powder slurry.

[0078] The microfluidic physical sunscreen powder slurry is applied to prepare a sunscreen cream; the formula of the sunscreen cream is shown in Table 1 below; the addition amount in Table 1 is the mass addition amount.

[0079] Table 1

[0080] The preparation steps of the sunscreen cream include: S1. Water, 1,3-butanediol, sodium chloride, p-hydroxyacetophenone, 1,2-hexanediol and dipropylene glycol were mixed in a 3# beaker, heated to 60±2℃, and dissolved uniformly to obtain a mixture one; S2. Zinc oxide powder slurry, titanium dioxide powder slurry, dimethicone, PEG-9 polydimethylsiloxane ethyl polydimethylsiloxane, polymethylsilsesquioxane, lithium montmorillonite and ethoxydiglycol were mixed in a 4# beaker, homogenized for 4±1 min until the materials were uniform to obtain a mixture two; S3. The mixture one was slowly poured into the 4# beaker under stirring, homogenized for 1-2 min until the materials were uniform to obtain the sunscreen cream, and the product was discharged.

[0081] Example 2 The present embodiment provides a microfluidic physical sunscreen powder slurry, a preparation method and application thereof, and the specific implementation manner is the same as that of Example 1; the difference lies in that: The nanometer zinc oxide in the present embodiment is sourced from Imperial Chemical, and the model number is MZX-508OTS.

[0082] The nanometer titanium dioxide in the present embodiment is sourced from Imperial Chemical, and the model number is Dexian®NM-H26.

[0083] Example 3 The present embodiment provides a microfluidic physical sunscreen powder slurry, a preparation method and application thereof, and the specific implementation manner is the same as that of Example 1; the difference lies in that: The nanometer titanium dioxide in the present embodiment is sourced from Imperial Chemical, and the model number is Dexian®NM-H26.

[0084] Example 4 The present embodiment provides a microfluidic physical sunscreen powder slurry, a preparation method and application thereof, and the specific implementation manner is the same as that of Example 1; the difference lies in that: The nano zinc oxide in the present embodiment is sourced from the Imperial Chemical, and the model is MZX-508OTS.

[0085] Comparative Example 1 The present comparative example provides a microfluidization physical sunscreen powder slurry, and a preparation method and application thereof, and the specific implementation manner is the same as that of Example 1; the difference lies in that the nano zinc oxide and the nano titanium dioxide are not subjected to microfluidization treatment, that is, the preparation steps of the sunscreen powder slurry are as follows: The preparation raw materials of the zinc oxide powder slurry are mixed in a 1# beaker, the materials are homogenized for 4±1 min until the materials are uniform, and 200-mesh filter cloth is used for filtration to obtain the zinc oxide powder slurry; The preparation raw materials of the titanium dioxide powder slurry are mixed in a 2# beaker, the materials are homogenized for 4±1 min, and 200-mesh filter cloth is used for filtration to obtain the titanium dioxide powder slurry.

[0086] Comparative Example 2 The present comparative example provides a microfluidization physical sunscreen powder slurry, and a preparation method and application thereof, and the specific implementation manner is the same as that of Example 2; the difference lies in that the nano zinc oxide and the nano titanium dioxide are not subjected to microfluidization treatment (operation reference Comparative Example 1).

[0087] Comparative Example 3 The present comparative example provides a microfluidization physical sunscreen powder slurry, and a preparation method and application thereof, and the specific implementation manner is the same as that of Example 3; the difference lies in that the nano zinc oxide and the nano titanium dioxide are not subjected to microfluidization treatment (operation reference Comparative Example 1).

[0088] Comparative Example 4 The present comparative example provides a microfluidization physical sunscreen powder slurry, and a preparation method and application thereof, and the specific implementation manner is the same as that of Example 4; the difference lies in that the nano zinc oxide and the nano titanium dioxide are not subjected to microfluidization treatment (operation reference Comparative Example 1).

[0089] Comparative Examples 5-12 Comparative Examples 5-12 provide a microfluidization physical sunscreen powder slurry, and a preparation method and application thereof, and the specific implementation manner is the same as that of Example 1; the difference lies in that the specifications and sources of the nano zinc oxide and the nano titanium dioxide are different, and specific reference is made to Table 2 below.

[0090] Table 2

[0091] Comparative Example 13 Comparative Example 13 provides a microfluidization physical sunscreen powder slurry, and a preparation method thereof, and the specific implementation manner is the same as that of Example 1; the difference lies in that the zinc oxide powder slurry and the titanium dioxide powder slurry are not prepared respectively, but the preparation raw materials of the zinc oxide powder slurry and the titanium dioxide powder slurry are directly mixed and subjected to microfluidization treatment.

[0092] Comparative Examples 14-16 Comparative Examples 14-16 provide a microjets physical sunscreen powder and its preparation method, with the specific implementation method being the same as Example 1; the difference lies in the microjets processing conditions, as shown in Table 3 below.

[0093] Table 3

[0094] Performance testing According to the operating procedures for testing the sun protection performance of cosmetics, the SPF and PFA values ​​of the sunscreens prepared in the examples and comparative examples were determined, and the test results are recorded in Table 3.

[0095] D 90 The particle size distribution of the sunscreens prepared in the examples and comparative examples was determined using a particle size distribution analyzer (manufacturer: HORIBA, model LA-960V2). 90 The particle size (the particle size value corresponding to a cumulative distribution percentage of 90%) was measured, and the test results are recorded in Table 3.

[0096] Simultaneously, the sunscreens of Examples 1, 2, and Comparative Example 1 were observed under a microscope, and the results are shown below. Figures 1-3 ; Figure 1 , Figure 2 The results showed that the sunscreen of the present invention had a uniform particle size distribution, a fine powder, and no agglomeration; while Figure 3 The particle distribution of the Comparative Example 1 sample was uneven, and obvious agglomeration could be observed.

[0097] The light transmittance of the sunscreens prepared in the examples and comparative examples was measured, and the test results are recorded in Table 4.

[0098] Anti-photoaging test method: An in vitro cell experiment was conducted using human skin fibroblasts as the research subject, and the following procedures were performed: 1) Collect cells when the confluence reaches approximately 85% under a microscope; discard the original culture medium in a clean bench and wash once with PBS buffer; add 1 mL of 0.25% trypsin (containing 0.02% EDTA), moisten the bottom, and incubate at 37°C for 3 min; after observing that most cells have detached under a microscope, add 2 mL of complete culture medium to stop digestion; centrifuge at 1000 rpm for 5 min; discard the supernatant, resuspend in 1 mL of complete culture medium, and count using an automated cell counter; add 5000 cells / 500 μL to each well of a 24-well plate and incubate at 37°C with 5% CO2 for 24 h; 2) After the cells adhered, discard the original culture medium and add 1 mL of the test sample (negative control wells were added with serum-free culture medium, test wells were added with ① serum-free culture medium containing 0.0002 wt% microfluidic sunscreen (Example 1) test sample, ② serum-free culture medium containing 0.0002 wt% conventional physical sunscreen sample (Comparative Example 1), and positive control wells were added with serum-free culture medium containing 100 μg / mL EGCG). The cells were then incubated at 37°C in a 5% CO2 incubator for 48 h. A blank control containing adherent cells was also set up, and the treatment method was the same as for the negative control wells. The cells were then incubated at 37°C in a 5% CO2 incubator for 48 h. 3) After 48 hours, discard the original culture medium and add 500 μL of PBS buffer; place the 24-well plate of the UV irradiation group under a UV irradiator and expose it to 40 mJ / cm². 2 Under ultraviolet light; after irradiation, discard the PBS buffer in the ultraviolet-irradiated group and the non-ultraviolet-irradiated group, and add 500 μL of serum-free culture medium to each well. Incubate at 37℃ in a 5% CO2 incubator for 24 h; the blank control wells are not exposed to ultraviolet light. 4) After 24 hours, collect 450 μL of culture supernatant from each well into a 1.5 mL sterile tube and perform detection according to the instructions for use of the human pro-MMP-1 enzyme-linked immunosorbent assay kit; the test results are shown in [link to results]. Figure 4 ; Figure 4 In the test results, the microfluidic sunscreen sample corresponds to Example 1, and the physical sunscreen sample corresponds to Example 1.

[0099] In the test samples of this invention, the blank control was not treated in any way, the negative control cells were directly irradiated with ultraviolet light, and the sample group and positive group were pre-treated with sunscreen ingredients before ultraviolet irradiation; the anti-photoaging effect was measured by comparing the MMP-1 secreted by the cells, with higher secretion indicating a poorer anti-photoaging effect. Figure 4 The test results showed that the microfluidic sunscreen samples significantly inhibited MMP-1 secretion compared to the negative control (P<0.05, indicated by *), while the physical sunscreen samples showed no significant difference. This demonstrates that the physical sunscreen products prepared using the microfluidic sunscreen preparation process of this invention exhibit significantly better NMP-1 inhibition and anti-photoaging effects compared to sunscreens prepared using conventional processes.

[0100] Table 4

[0101] The test results in Table 4 show that the present invention uses specific nano-zinc oxide and nano-titanium dioxide, preferably NAOCOS ZS1004B (Changzhou Nao) or MZX-508OTS (Imperial Chemical) for nano-zinc oxide, and Dexian® NM-H26 (Guangzhou Dexian) or MICRO TITANIUM DIOXIDE MT-100TV (Imperial Chemical) for nano-titanium dioxide. These are then subjected to microfluidic treatment before mixing and homogenization, which significantly improves the SPF value of the sunscreen, reduces the particle size, and increases light transmittance, resulting in excellent anti-photoaging properties. Conversely, when the raw materials are not microfluidically treated, or when other specifications of zinc oxide or titanium dioxide are selected, or when the microfluidic process conditions are adjusted, the sun protection effect, particle size, and light transmittance of the product deteriorate, failing to meet the requirements for sunscreen products.

Claims

1. A microfluidic physical sunscreen powder, characterized in that, The sunscreen powder includes zinc oxide powder and titanium dioxide powder; by weight: The raw materials for preparing the zinc oxide slurry include 5-25 parts of nano zinc oxide, 5-15 parts of emollient, 0.5-5 parts of first emulsifier, and 0.1-1 parts of first binder; The raw materials for preparing the titanium dioxide slurry include 5-25 parts of nano titanium dioxide, 8-20 parts of emollient, 0.1-2 parts of second emulsifier, 0.1-2 parts of second binder and 0.1-1 parts of third binder; The zinc oxide slurry and titanium dioxide slurry were respectively treated by microfluidic jet.

2. The microfluidic physical sunscreen powder according to claim 1, characterized in that, The conditions for the microjet processing are: microjet channel aperture of 100-300 nm and microjet pressure of 150-200 MPa.

3. The microfluidic physical sunscreen powder according to claim 2, characterized in that, The nano zinc oxide is either NAOCOSZS1004B or MZX-508OTS.

4. The microfluidic physical sunscreen powder according to claim 2, characterized in that, The nano-titanium dioxide is either Dexian® NM-H26 or MICRO TITANIUM DIOXIDE MT-100TV.

5. The microfluidic physical sunscreen powder according to claim 1, characterized in that, The emollient is polydimethylsiloxane.

6. The microfluidic physical sunscreen powder according to claim 1, characterized in that, Both the first emulsifier and the second emulsifier are polyglycerol-3-polydimethylsiloxane-3-dimethylsiloxane.

7. The microfluidic physical sunscreen powder according to claim 6, characterized in that, The raw materials for preparing the titanium dioxide slurry also include 0.1-2 parts of a third emulsifier; The third emulsifier is PEG-9 polydimethylsiloxane-ethyl polydimethylsiloxane.

8. A method for preparing a microfluidic physical sunscreen powder according to claim 7, characterized in that, The preparation steps of the sunscreen powder include: Nano zinc oxide, emollient, first emulsifier and first binder are mixed, homogenized and filtered, and then subjected to microfluidic treatment to obtain zinc oxide slurry; Nano-titanium dioxide, emollient, second emulsifier, second binder and third binder are mixed, homogenized and filtered, and then subjected to microfluidic treatment to obtain titanium dioxide slurry.

9. An application of a microfluidic physical sunscreen powder according to any one of claims 1-7; the sunscreen powder is used in the preparation of sunscreen products, characterized in that, The sun protection products include sunscreen cream, sunscreen lotion, sunscreen spray, or sunscreen gel.

10. The application according to claim 9, characterized in that, The sunscreen product is a sunscreen lotion; The raw materials for preparing the sunscreen include: sunscreen powder, moisturizer, thickener, antioxidant, adsorbent, emollient, fourth emulsifier and solvent; The amount of sunscreen powder added to the sunscreen lotion is 20-60wt%.

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