Sunscreen pressed powder and preparation method thereof

Abstract

The invention provides a sunscreen pressed powder and a preparation method thereof. The sunscreen pressed powder comprises a powder matrix and a sunscreen agent, the powder matrix comprises an organosilicon microsphere powder vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer, the average particle size of the powder matrix is 6-12 [mu] m, and the mass percentage content of the powder matrix in the sunscreen pressed powder is 15%-25%; the sun-screening agent comprises a physical sun-screening agent and a chemical sun-screening agent, the physical sun-screening agent is at least one of nano titanium dioxide and nano zinc oxide, and the mass percentage content of the physical sun-screening agent in the sun-screening pressed powder is 10%-20%. According to the sunscreen pressed powder, the physical sunscreen agent and the chemical sunscreen agent are added in a composite mode, comprehensive broad-spectrum sunscreen can be achieved, the good sunscreen effect is achieved, the false white problem is avoided, the shrinkage rate of the powder is small in the preparation process, and the drop resistance of the pressed powder is good.

Description

Technical Field

[0001] The present application belongs to the technical field of cosmetics, and in particular relates to a sunscreen powder cake and a preparation method thereof. Background Art

[0002] By using physical sunscreen or chemical sunscreen in powder, powder can be made to have sun protection function. Physical sunscreen has the advantages of high safety and good stability, but the use of physical sunscreen will bring about the problem of "false white". The main reason for the false white of physical sunscreen is that the physical sunscreen does not blend well with the stratum corneum on the surface of the skin, forming a white "film" effect; and the particles of physical sunscreen are large, which reduces the permeability, forming a visual effect on the surface of the skin, sometimes making people mistakenly think that the skin is covered with a thick layer of white dirt.

[0003] In addition, powder products are prone to shrinkage during the drying and water removal steps of the preparation process, so drop resistance is also something that needs to be paid close attention to when preparing powder products. Summary of the invention

[0004] The embodiment of the present application provides a sunscreen powder cake and a preparation method thereof. The sunscreen powder cake provided by the present application adopts a composite addition of physical sunscreen agents and chemical sunscreen agents, which can achieve comprehensive and broad-spectrum sun protection and achieve a good sunscreen effect without the problem of false whiteness. In addition, the powder cake has a small shrinkage rate during the preparation process and has good drop resistance.

[0005] In a first aspect, an embodiment of the present application provides a sunscreen powder cake, comprising a powder matrix and a sunscreen agent, wherein the powder matrix comprises silicone microsphere powder, which is a vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer, and the average particle size of the silicone microsphere powder is 6 to 12 μm; and the mass percentage of the silicone microsphere powder in the sunscreen powder cake is 15%-25%; the sunscreen agent comprises a physical sunscreen agent and a chemical sunscreen agent, the physical sunscreen agent is at least one of nano titanium dioxide and nano zinc oxide, and the mass percentage of the physical sunscreen agent in the sunscreen powder cake is 10%-20%.

[0006] In the sunscreen powder of the present application, physical sunscreen and chemical sunscreen are added in combination to achieve comprehensive broad-spectrum sunscreen and achieve better sunscreen effects. In the sunscreen powder provided in the present application, silicone microsphere powder is also used: vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer. The conventional role of this kind of silicone microsphere powder in cosmetics is to increase the silky skin feel and soft focus effect. The inventor unexpectedly discovered that the sunscreen powder of the present application uses silicone microsphere powder with a content of 15%-25% and an average particle size of 6 to 12 μm in the powder matrix. In addition to increasing the silky skin feel and soft focus effect, it can also significantly reduce the false white problem caused by the 10%-20% physical sunscreen in the powder formula.

[0007] According to an embodiment of the first aspect of the present application, the mass ratio of the physical sunscreen agent to the silicone microsphere powder is (0.4-1.33):1.

[0008] According to an embodiment of the first aspect of the present application, the average particle size of the physical sunscreen is 20 nm to 30 nm.

[0009] The organosilicon microsphere powder vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer used in the sunscreen powder of the present application is a kind of organosilicon microsphere powder with shrinkage. If the amount added to the powder product exceeds 8%, it will lead to an increase in the shrinkage rate and cracking possibility after the powder is formed, and the powder is not resistant to falling. In this regard, the inventors further found that by controlling the average particle size of the physical sunscreen to 20nm to 30nm, and making the mass ratio of the physical sunscreen to the organosilicon microsphere powder within the range of (0.4 to 1.33): 1, the organosilicon microsphere powder can achieve better mutual mixing with the physical sunscreen at the microscopic level during the mixing and preparation process, reduce the intermolecular gap, and maintain the stability of the mutual mixing, significantly reduce the shrinkage rate during the powder preparation process, and improve the anti-falling property of the sunscreen powder.

[0010] According to an embodiment of the first aspect of the present application, the nano titanium dioxide and / or nano zinc oxide is / are surface modified.

[0011] According to an embodiment of the first aspect of the present application, the powder matrix also includes a binder, and the binder includes at least one of a Chondrus crispus extract and xanthan gum, and the mass percentage of the binder in the sunscreen powder is 0.3%-0.8%.

[0012] According to an embodiment of the first aspect of the present application, the powder matrix also includes one or more of a filler, a colorant, a skin moisturizer, a skin feel regulator, an antioxidant, a thickener, a film former, an emulsifier, and a preservative.

[0013] In order to better ensure the anti-drop property of the sunscreen powder, the present application adds two binders, Chondrus crispus extract and xanthan gum, to the formula to further strengthen the powder block and solve the problem of rough, dry texture and easy powder sticking caused by other binders.

[0014] According to the embodiment of the first aspect of the present application, the mass percentage of the powder matrix in the sunscreen powder cake is 65% to 80%, and the mass percentage of the sunscreen agent in the sunscreen powder cake is 20% to 35%.

[0015] In a second aspect, an embodiment of the present application provides a method for preparing a sunscreen powder cake, comprising the following steps: providing raw materials for preparing a sunscreen powder cake, mixing the raw materials to obtain a mixed material body; filling the mixed material body into a mold, and microwave drying it to a moisture content of ≤20% to obtain a powder master product; freezing the powder master product at -85 to -70°C; separating the frozen powder master product from the mold, and drying it to obtain a sunscreen powder cake.

[0016] According to an embodiment of the second aspect of the present application, the step of freezing the powdered masterbatch at -85 to -70°C is performed in a liquid nitrogen tunnel.

[0017] According to an embodiment of the second aspect of the present application, the drying is vacuum freeze drying.

[0018] The process of removing solvents must be carried out during the preparation of powder cakes. The shrinkage and deformation of the product during the process of removing solvents is an important factor leading to the poor drop resistance of the powder cake. In this application, the powder master product is ultra-low-temperature frozen in a liquid nitrogen tunnel at -85 to -70°C. The powder master product quickly passes through the maximum ice crystal formation zone, and the distribution of ice crystals in the powder master product is more uniform and dense, making the skin feel of the freeze-dried product softer, the product size variable is smaller and easier to control, and the product structure is more stable. In addition, vacuum freeze drying is to freeze the solvent-containing material in a frozen state, and directly sublimate the solvent frozen into ice crystals in the material body into a gaseous state without passing through a liquid state. Compared with other drying methods, the vacuum freeze-dried powder block product size variable is smaller and easier to control, the product structure is more stable, and the drop resistance is better. In summary, this application further reduces the shrinkage rate in the powder cake preparation process and improves the drop resistance of the sunscreen powder cake by using ultra-low temperature freezing and vacuum freeze drying in a liquid nitrogen tunnel at -85 to -70°C in the preparation process. DETAILED DESCRIPTION

[0019] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0020] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0021] Physical sunscreens have the advantages of high safety and good stability, but the use of physical sunscreens can cause the problem of "false whiteness". In addition, powder products are prone to shrinkage during the drying and water removal steps in the preparation process, resulting in insufficient anti-fall performance. In order to solve the above problems, the inventors of this application provide a sunscreen powder and a preparation method thereof.

[0022] In a first aspect, an embodiment of the present application provides a sunscreen powder cake, comprising a powder matrix and a sunscreen agent, wherein the powder matrix comprises silicone microsphere powder, which is a vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer, and the average particle size of the silicone microsphere powder is 6 to 12 μm; and the mass percentage of the silicone microsphere powder in the sunscreen powder cake is 15%-25%; the sunscreen agent comprises a physical sunscreen agent and a chemical sunscreen agent, the physical sunscreen agent is at least one of nano titanium dioxide and nano zinc oxide, and the mass percentage of the physical sunscreen agent in the sunscreen powder cake is 10%-20%.

[0023] In the sunscreen powder of the present application, physical sunscreen and chemical sunscreen are added in combination to achieve comprehensive broad-spectrum sunscreen and achieve better sunscreen effects. In the sunscreen powder provided in the present application, silicone microsphere powder is also used: vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer. The conventional role of this kind of silicone microsphere powder in cosmetics is to increase the silky skin feel and soft focus effect. The inventor unexpectedly discovered that the sunscreen powder of the present application uses silicone microsphere powder with a content of 15%-25% and an average particle size of 6 to 12 μm in the powder matrix. In addition to increasing the silky skin feel and soft focus effect, it can also significantly reduce the false white problem caused by the 10%-20% physical sunscreen in the powder formula.

[0024] Specifically, the sunscreen powder is selected from powder, blush, eye shadow or highlighter powder. The sunscreen powder can also include products with other functions.

[0025] The sunscreen powder of the present application adds silicone microsphere powder vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosslinked polymer to increase the silky skin feel and soft focus effect. In addition, the inventors of the present application accidentally discovered during the experiment that when ball-shaped silicone microsphere powder with an average particle size of 6 to 12 μm is used in the powder matrix, in addition to increasing the silky skin feel and soft focus effect, it can also significantly reduce the false white problem caused by the physical sunscreen in the powder formula.

[0026] Exemplarily, the average particle size of the organosilicon microsphere powder is 6 μm, 6.6 μm, 7.2 μm, 7.8 μm, 8.4 μm, 9 μm, 9.6 μm, 10.2 μm, 10.8 μm, 11.4 μm, 12 μm or an interval range consisting of any two of the above values.

[0027] In the sunscreen powder cake of the present application, a solution combining physical sunscreen agents and chemical sunscreen agents is adopted to achieve comprehensive and broad-spectrum sunscreen and achieve better sunscreen effects.

[0028] The particle size of the nanoparticles used in the physical sunscreen in the present application is between 10 nm and 100 nm. Preferably, the particle size of the physical sunscreen is between 20 nm and 30 nm.

[0029] In some embodiments, the mass ratio of the physical sunscreen to the chemical sunscreen is (0.9-1):1.

[0030] The usage range of physical sunscreen and chemical sunscreen is within the above range, which can make the sunscreen powder have full-band sun protection performance.

[0031] Illustratively, the mass ratio of the physical sunscreen to the chemical sunscreen is 0.9:1, 0.91:1, 0.92:1, 0.93:1, 0.94:1, 0.95:1, 0.96:1, 0.97:1, 0.98:1, 0.99:1 or 1:1.

[0032] In some embodiments, the mass ratio of the physical sunscreen agent to the silicone microsphere powder is (0.4-1.33):1.

[0033] Exemplarily, the mass ratio of the physical sunscreen to the silicone microsphere powder is 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1 or 1.33:1.

[0034] The organosilicon microsphere powder vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer used in the sunscreen powder of the present application is a kind of organosilicon microsphere powder with shrinkage. If the amount added to the powder product exceeds 8%, it will lead to an increase in the shrinkage rate and cracking possibility after the powder is formed, and the powder is not resistant to falling. In this regard, the inventors further found that by controlling the average particle size of the physical sunscreen to 20nm to 30nm, and making the mass ratio of the physical sunscreen to the organosilicon microsphere powder within the range of (0.4 to 1.33): 1, the organosilicon microsphere powder can achieve better mutual mixing with the physical sunscreen at the microscopic level during the mixing and preparation process, reduce the intermolecular gap, and maintain the stability of the mutual mixing, significantly reduce the shrinkage rate during the powder preparation process, and improve the anti-falling property of the sunscreen powder.

[0035] In some embodiments, the physical sunscreen is nano titanium dioxide, nano zinc oxide, etc. In order to improve the skin feel, the nano titanium dioxide and / or nano zinc oxide are surface modified. It can be that one of the nano titanium dioxide and the nano zinc oxide is surface modified, or it can be that the nano titanium dioxide and the nano zinc oxide are both surface modified. Preferably, the nano titanium dioxide is surface modified nano titanium dioxide, and illustratively, the nano titanium dioxide is modified by stearic acid and aluminum hydroxide. Nano titanium dioxide modified by stearic acid and aluminum hydroxide can make the skin feel softer.

[0036] In some embodiments, the powder matrix further includes a binder, the binder includes at least one of Chondrus crispus extract and xanthan gum, and the mass percentage of the binder in the sunscreen powder is 0.3%-0.5%.

[0037] In order to solve the problems of powder blocks that cannot be formed, are fragile, and lack resistance to falling, the formula of the present application achieves a more solid effect by adding a binder. Adding the above-mentioned amounts of Chondrus crispus extract and xanthan gum to the sunscreen powder can further strengthen the powder block. At the same time, Chondrus crispus extract and xanthan gum are in a liquid colloid state, which also solves the problems of rough and dry texture and easy powder sticking. At the same time, Chondrus crispus extract and xanthan gum also have the effect of preventing skin moisture loss and improving dry and rough skin. Therefore, the sunscreen powder of the present application can achieve a broad-spectrum sunscreen effect, and at the same time, there is no problem of false white and the resistance to falling is good.

[0038] In some embodiments, the powder matrix further comprises one or more of a filler, a colorant, a skin moisturizer, a skin feel regulator, an antioxidant, a thickener, a film former, an emulsifier, and a preservative.

[0039] In order to improve skin feel, in some embodiments, the powder matrix further includes 40% to 60% of a skin feel regulator, and the skin feel regulator includes one or more of silica, synthetic fluorphlogopite, and talc.

[0040] Exemplarily, the content of the skin feel regulator in the powder matrix is ​​40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60% or an interval range consisting of any two of the above values.

[0041] Silica is effective in improving skin feel. In addition, silica can also control oil.

[0042] Synthetic fluorphlogopite can increase the brightness of sunscreen powder, increase the skin texture and touch after use, and enhance the shiny visual effect. In order to further improve the skin feel, in some embodiments, the synthetic fluorphlogopite can also be modified with aluminum hydroxide and triethoxyoctylsilane.

[0043] Talc has good lubricity and can act as a slip agent, making the sunscreen powder smoother and easier to apply.

[0044] In some embodiments, the thickener and film former are selected from natural water-soluble polymers or their derivatives, synthetic water-based polymers or water-based inorganic thickeners.

[0045] The natural water-soluble polymer or its derivative is selected from at least one of alginic acid, agar, carrageenan, xanthan gum, gellan gum, crispy chondrus crispus, xanthan gum, guar gum, tamarind gum, tara gum, gum arabic, tragacanth gum, tara gum, pectin, arabogalactan, wheat protein, soybean protein, gelatin, casein, chitosan, gelatinized polysaccharide, cyclodextrin, hyaluronic acid, konjac gum, tremella polysaccharide, codyl gelatin, microcrystalline cellulose, methylcellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, starch phosphate, starch, sodium hydroxymethyl starch, sodium polyacrylate grafted starch, and hydroxypropyl guar gum.

[0046] The synthetic water-based polymer is selected from at least one of acrylic acid (esters) / C10-30 alkyl acrylate crosspolymer, carbomer, acrylic acid (esters) / octylacrylamide copolymer, acrylic acid (esters) / ethylhexyl acrylate copolymer, sodium acrylate / sodium acryloyldimethyl taurate copolymer, acrylic acid (esters) / octylacrylamide copolymer, styrene / acrylic acid (esters) copolymer, acrylic acid (esters) copolymer, hydroxyethyl acrylate / sodium acryloyldimethyl taurate copolymer, polyacrylate crosspolymer-6, acrylic acid (esters) / stearyl alcohol polyether-20 methacrylate copolymer, ammonium acryloyldimethyl taurate / behenyl alcohol polyether-25 methacrylate crosspolymer, acrylic acid (esters) copolymer ammonium, sodium polyacrylate, sodium polyacryloyldimethyl taurate, polyacrylamide, polyvinyl pyrrolidone, polyvinyl alcohol, VP / VA copolymer, polyurethane-1, and polyurethane-35.

[0047] The aqueous inorganic thickener is selected from at least one of aluminum magnesium silicate, sodium magnesium lithium silicate, lithium magnesium silicate, sodium magnesium silicate, montmorillonite or derivatives thereof.

[0048] In some embodiments, the filler comprises at least one of starch, cellulose and its derivatives.

[0049] Starch is widely available, cheap, has certain hygroscopicity and filling properties, and can absorb moisture and oil from the skin surface. Cellulose and its derivatives such as microcrystalline cellulose and sodium carboxymethyl cellulose have good thickening and filling effects, can adjust viscosity and texture, and make the product more stable.

[0050] In some embodiments, the emollient is selected from at least one of alcohols, silicone oils, mineral oils, synthetic oils, animal and plant oils, or derivatives thereof.

[0051] The animal and plant oils or their derivatives are selected from at least one of glycerin, propylene glycol, dipropylene glycol, pentylene glycol, butylene glycol, ethylene glycol, hexylene glycol, sorbitol, xylitol, polyethylene glycol, polydimethylsiloxane, caprylyl polymethylsiloxane, phenyl trimethicone, cetyl polydimethylsiloxane, C30-45 alkyldimethylsilyl polypropyl silsesquioxane, bis-PEG-18 methyl ether dimethyl silane, white mineral oil, petrolatum, hydrogenated polyisobutene, lanolin and its derivatives, octyldodecanol, caprylic / capric triglyceride, ethylhexyl palmitate, bis-diglyceryl polyacyl adipate-2, isononyl isononanoate, jojoba seed oil, coconut oil, hydrogenated coconut glycerides, white meadowfoam seed oil, olive oil, squalane, C9-12 alkane, coconut alcohol-caprylate / caprate, tocopheryl acetate, and methyl gluceth-10.

[0052] In some embodiments, the colorant is selected from at least one of iron oxide (CI 77499, CI 77491, CI77492), titanium dioxide (CI 77891), iron blue (CI 77510), ultramarine (CI 77007), manganese violet (CI 77742), chromium oxide green (CI 77288), chromium hydroxide green, carmine (CI75470), carbon black (CI 77266), CI 15850, CI 19140, CI 45410, CI 16035, CI 45380, CI 17200, CI 73360, CI 42090, and CI 47005.

[0053] In some embodiments, the antioxidant includes one or more of a synthetic antioxidant and a natural antioxidant. For example, the synthetic antioxidant includes butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tert-butylhydroquinone (TBHQ), etc.; the natural antioxidant includes tea polyphenols, phytic acid, vitamin C, vitamin E, etc.

[0054] In some embodiments, the preservative is selected from at least one of phenoxyethanol, parabens, chlorphenesin, potassium sorbate, sodium benzoate or preservative enhancers.

[0055] The preservative synergist is selected from at least one of caprylyl glycol, p-hydroxyacetophenone, ethylhexylglycerin, 1,2-hexanediol, caprylhydroxamic acid, 1,2-pentanediol, glyceryl caprylate, and cymene.

[0056] In a second aspect, an embodiment of the present application provides a method for preparing a sunscreen powder cake, comprising the following steps: providing raw materials for preparing a sunscreen powder cake, mixing the raw materials to obtain a mixed material body; filling the mixed material body into a mold, and microwave drying it to a moisture content of ≤20% to obtain a powder master product; freezing the powder master product at -85 to -70°C; separating the frozen powder master product from the mold, and drying it to obtain a sunscreen powder cake.

[0057] Among them, in the mixing step, the raw materials for preparing the sunscreen powder can be purchased commercially or homemade. It is understood that the raw materials for preparing the sunscreen powder generally include a powder phase component, an oil phase component and an aqueous phase component. The raw materials can be mixed in various ways commonly used in the prior art to add the raw materials step by step and mix them evenly, such as mechanical stirring, etc., and homogenization, defoaming and other operations can be added during the mixing process. Different mixing methods and steps can be used according to different raw materials, and the present application is not limited thereto.

[0058] Exemplarily, the raw materials include a powder phase component, an oil phase component and an aqueous phase component; the powder phase component includes: one or more of a powder matrix and a colorant; the oil phase component includes: one or more of an emulsifier, a moisturizer, an antioxidant, and a sunscreen; the aqueous phase component includes: one or more of a solvent, a binder, a thickener, a film former, a moisturizer, an emulsifier, and a preservative.

[0059] In some embodiments, the step of freezing the powder precursor at -85 to -70°C is performed in a liquid nitrogen tunnel.

[0060] Liquid nitrogen tunnel is also called liquid nitrogen tunnel quick freezer. It is a device that uses liquid nitrogen as a cold source, adopts a continuous production method, and sends materials into the quick freezing tunnel through a conveyor belt to achieve continuous entry and exit and rapid freezing of materials. The step of freezing the powder master product at -85 to -70 ° C is in the liquid nitrogen tunnel. The raw material components in the mixed material body undergo molecular quick freezing in an extremely low temperature environment in the liquid nitrogen quick freezing device. The mixed material body contains components such as oils and emulsions. During its freezing and shaping process, it will experience a maximum ice crystal formation zone, which is about -10 to 0 ° C. The temperature range, about 80% of the liquid (water, emulsion, etc.) will turn into ice. Different from the ordinary freezing implemented before demoulding in the prior art, the powder master product quickly passes through the maximum ice crystal formation zone during the molecular quick freezing process completed in the liquid nitrogen tunnel in this application. The distribution of ice crystals in the powder master product is smaller, more uniform and dense, making the skin feel of the freeze-dried product softer, the product size variable is smaller and easier to control, the product structure is more stable, and the anti-drop ability is better.

[0061] In some embodiments, the drying is vacuum freeze drying.

[0062] After freezing, the present application uses vacuum freeze drying to prepare sunscreen powder. Since the drying is carried out in a frozen state, the volume remains almost unchanged, the original structure is maintained, and no concentration occurs. Vacuum freeze drying is to remove the solvent frozen as ice crystals in the material body by sublimating it directly into a gaseous state without passing through a liquid state when the solvent-containing material is in a frozen state. Compared with other drying methods, the size variables of the vacuum freeze-dried powder products are smaller and easier to control, and the product structure is more stable and has better drop resistance. In summary, the present application further reduces the shrinkage rate in the powder preparation process and improves the drop resistance of the sunscreen powder by using liquid nitrogen tunnel ultra-low temperature freezing and vacuum freeze drying at -85 to -70°C in the preparation process.

[0063] Example

[0064] The following examples describe the disclosure of the present application in more detail, and these examples are for illustrative purposes only, as various modifications and variations within the scope of the disclosure of the present application are apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by mass, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further treatment, and the instruments used in the examples are commercially available.

[0065] It should be noted that the addition of chemical sunscreens and physical sunscreens can give cosmetics certain sunscreen properties, which is well known in the art. The selection of the type and amount of sunscreens and the sunscreen ability (such as the sun protection index) that the sunscreen products ultimately possess are not technical issues explored and solved by this application. Therefore, in order to more clearly reflect the distinguishing features and functions of this application relative to the prior art, the same physical sunscreen and chemical sunscreen are selected in the following examples.

[0066] Example 1

[0067] The raw material components of the sunscreen powder cake of this embodiment are shown in Table 1, and the preparation steps are as follows:

[0068] Mixing: (1) Heat phase A and disperse it evenly; (2) Add phase C to phase A and homogenize and emulsify it at a temperature of 75±5℃; (3) Add phase B to (2) and mix evenly at a temperature of 75±5℃; (4) Cool the material to 50±5℃; (5) Add phase D (which needs to be pre-dissolved) and phase E to (4) and mix evenly, and vacuum degas at 50±5℃ to obtain a mixed material.

[0069] Filling: Fill the material into the mold according to the preset amount, and microwave dry it until the moisture content is ≤20% to obtain the powder masterbatch.

[0070] Freezing demoulding: The powdered mother product is frozen through a -80℃ liquid nitrogen tunnel, and then the powdered mother product is separated from the mold to complete demoulding;

[0071] Vacuum freeze drying: The powdered master product after demoulding is subjected to vacuum freeze drying until almost all the water in the powdered master product is removed to obtain a sunscreen powder cake.

[0072] Among them, vacuum freeze drying is carried out in a freeze dryer, and the vacuum freeze drying procedure includes freezing, sublimation drying and analytical drying. Freezing includes: freezing at 42℃~45℃ for 1h 1.5 hours; sublimation drying specifically includes: heating the material to -3℃~3℃, the heating treatment includes several first heating stages and several first insulation stages, and the first heating stage and the first insulation stage are alternately carried out; the first heating stage is heated at 0.6~0.8℃ / min for 15~18min, and the first insulation time is 1.6~1.8h; analytical drying specifically includes: drying the material at 25℃~50℃, the drying treatment includes several second heating stages and several second insulation stages, and the second heating stage and the second insulation stage are alternately carried out; the second heating stage is heated at 0.6~0.8℃ / min for 15~18min, and the second insulation time is 1.6~1.8h.

[0073] Embodiment 2-5

[0074] The difference between Examples 2-5 and Example 1 is that the amounts of silicone microsphere powder and physical sunscreen agent used are different.

[0075] Embodiment 6-8

[0076] The difference between Example 6-7 and Example 1 is that the amount of binder (xanthan gum and Chondrus crispus extract) is different, and the amount of propylene glycol is adjusted so that the sum of the amount of binder and propylene glycol is the same as that of Example 1, and the physical sunscreen in Examples 6-7 uses nano zinc oxide instead of nano titanium dioxide. In Example 8, the binder is replaced by magnesium myristic acid, and the amount used is the same as the total amount of binder in Example 1.

[0077] Comparative Example 1

[0078] The difference between Comparative Example 1 and Example 1 is that the comparative example 1 does not contain organic silicon microsphere powder.

[0079] Comparative Examples 2-3

[0080] The difference between Comparative Examples 2-3 and Example 1 is that the dosage of the silicone microsphere powder and the physical sunscreen is too large or too small.

[0081] Comparative Examples 4-5

[0082] The difference between Comparative Example 4 and Example 1 is that the average particle size of the organosilicon microsphere powder is 3 μm; the difference between Comparative Example 5 and Example 1 is that the average particle size of the organosilicon microsphere powder is 18 μm.

[0083] Comparative Example 6

[0084] The difference between Comparative Example 6 and Example 1 is that: before demoulding, ultra-low temperature freezing in a liquid nitrogen tunnel is not used, but freezing in a -25°C freezer is used; the drying step after demoulding does not use vacuum freeze drying, but drying at 60°C is used.

[0085] Test Section

[0086] According to the methods of Examples 1 to 8 and Comparative Examples 1 to 6, 100 sunscreen powder foundations were prepared respectively, and the false white test and diameter shrinkage rate test were carried out.

[0087] 1) False white test

[0088] 100 subjects were selected and divided into 10 groups. The sunscreen powder of the embodiment of the present application and the comparative example were used for testing respectively. Whether the subjects had a false white problem after using the powder was observed by naked eyes. The recorded results were based on the observation results of more than 90% of the 100 subjects.

[0089] 2) Diameter shrinkage detection

[0090] The diameter D of the mold and the diameter d of the prepared sunscreen powder cake were measured with a vernier caliper. The diameter shrinkage rate was calculated using the following formula:

[0091] Diameter shrinkage = [(Dd)\D]*100%

[0092] Wherein, D is the diameter of the filling mold, and d is the diameter of the prepared powder cake.

[0093] The average value of the diameter shrinkage of 100 powder cakes was recorded.

[0094] The raw material compositions of Examples 1 to 8 and Comparative Examples 1 to 6 are shown in Table 1.

[0095] The results of the contents of some components, the false white test, and the diameter shrinkage test in the sunscreen powder cakes prepared in Examples 1 to 8 and Comparative Examples 1 to 6 are shown in Table 2.

[0096]

[0097]

[0098] Examples 1 to 8 use the technical solution provided by the present application to prepare sunscreen powder cakes. Physical sunscreen agents and chemical sunscreen agents are added in combination to achieve comprehensive broad-spectrum sunscreen and achieve better sunscreen effects. More importantly, Examples 1 to 8 all use 15%-25% of organosilicon microsphere powder with an average particle size of 6 to 12 μm in the sunscreen powder cakes: vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosslinked polymer. In addition to its conventional effect of increasing silky skin feel and softening focus, the above-mentioned organosilicon microsphere powder can also significantly reduce the false white problem caused by the physical sunscreen agent in the powder cake formula. From the false white test data in Table 2, it can be seen that although the sunscreen powder cakes of Examples 1 to 8 add physical sunscreen agents, no false white phenomenon occurs, indicating that the technical solution provided by the present application can solve the false white problem caused by the addition of physical sunscreen agents. However, since no silicone microsphere powder was added to Comparative Example 1, the false white problem was serious; although silicone microsphere powder was added to Comparative Example 2, the added amount was small and it still failed to effectively improve the false white problem caused by physical sunscreens.

[0099] Vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer silicone microsphere powder is a kind of silicone microsphere powder with shrinkage. Once the amount added to the powder product exceeds 8%, the shrinkage rate of the powder after molding will increase, the possibility of cracking will increase, and the powder will not be able to resist falling. In this regard, the present application also takes a series of measures to reduce the adverse effects of the addition of silicone microsphere powder on the shrinkage rate of the powder. For example: when the average particle size of the silicone microsphere powder is within 6-12μm, the average particle size of the physical sunscreen is controlled to be 20nm~30nm, and the mass ratio of the physical sunscreen to the silicone microsphere powder is within the range of (0.4~1.33):1, the silicone microsphere powder can be better mixed with the physical sunscreen at the microscopic level during the mixing and preparation process, reduce the intermolecular gap, and maintain the stability of the mixing. At the same time, suitable binders such as wrinkled chondrus crispus extract and xanthan gum are used to reduce the shrinkage rate of the powder and maintain a good makeup effect and skin feel. From Comparative Example 3, it can be seen that when the amount of organosilicon microsphere powder added relative to the physical sunscreen agent is too large, although the sunscreen powder does not have the problem of false white, the diameter shrinkage rate during the powder preparation process increases significantly. From Comparative Examples 4-5, it can be seen that when the average particle size of the organosilicon microsphere powder is too small or too large, the shrinkage rate of the powder increases, and it is even not conducive to solving the problem of false white.

[0100] In addition, the present application also implements liquid nitrogen tunnel freezing demoulding and vacuum freeze drying processes during the preparation process. First, the powder masterbatch is frozen in a liquid nitrogen tunnel at -85 to -70°C, and the powder masterbatch quickly passes through the maximum ice crystal formation zone, and the distribution of ice crystals in the powder masterbatch is more uniform and dense; the freeze-dried product feels softer, the product size variable is smaller and easier to control, and the product structure is more stable. Secondly, vacuum freeze drying freezes the solvent-containing material in a frozen state, and the solvent frozen into ice crystals in the material body is directly sublimated into a gaseous state without passing through a liquid state. Compared with other drying methods, the vacuum freeze-dried powder block product size variable is smaller and easier to control, the product structure is more stable, and the anti-drop ability is better. In summary, the present application further reduces the shrinkage rate in the powder preparation process and improves the anti-drop property of the sunscreen powder by using ultra-low temperature freezing and vacuum freeze drying in a liquid nitrogen tunnel at -85 to -70°C in the preparation process. It can be seen from Comparative Example 6 that even if the same formula is used, if liquid nitrogen tunnel ultra-low temperature freezing and vacuum freeze drying are not used in the preparation process, the shrinkage rate of the powder cake will increase significantly, which is not conducive to the anti-drop property of the powder cake.

[0101] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A sunscreen powder cake, characterized in that: Including powder base and sunscreen, The powder matrix includes organic silicon microsphere powder, which is a vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer, and the average particle size of the organic silicon microsphere powder is 6 to 12 μm; and the mass percentage of the organic silicon microsphere powder in the sunscreen powder is 15% to 25%; The sunscreen comprises a physical sunscreen and a chemical sunscreen. The physical sunscreen is at least one of nano titanium dioxide and nano zinc oxide, and the mass percentage of the physical sunscreen in the sunscreen powder is 10%-20%.

2. The sunscreen powder according to claim 1, characterized in that: The mass ratio of the physical sunscreen agent to the organic silicon microsphere powder is (0.4-1.33):

1.

3. The sunscreen powder according to claim 1, characterized in that: The average particle size of the physical sunscreen is 20nm to 30nm.

4. The sunscreen powder according to claim 1, characterized in that: The nano titanium dioxide and / or nano zinc oxide is / are surface modified.

5. The sunscreen powder according to claim 1, characterized in that: The powder matrix also includes a binder, which includes at least one of a Chondrus crispus extract and xanthan gum. The mass percentage of the binder in the sunscreen powder cake is 0.3%-0.5%.

6. The sunscreen powder according to claim 1, characterized in that: The powder matrix may also include one or more of a filler, a colorant, a skin moisturizer, a skin feel regulator, an antioxidant, a thickener, a film former, an emulsifier, and a preservative.

7. The sunscreen powder according to claim 1, characterized in that: The mass percentage of the powder matrix in the sunscreen powder cake is 65% to 80%, and the mass percentage of the sunscreen agent in the sunscreen powder cake is 20% to 35%.

8. A method for preparing the sunscreen powder according to any one of claims 1 to 7, characterized in that: The steps include: Providing raw materials for preparing sunscreen powder, and mixing the raw materials to obtain a mixed material body; Filling the mixed material into a mold, and drying by microwave until the water content is ≤20%, to obtain a powdered masterbatch; Freezing the powdered product at -85 to -70°C; The frozen powdered mother product is separated from the mold and dried to obtain a sunscreen powder cake.

9. The method for preparing the sunscreen powder according to claim 8, characterized in that: The step of freezing the powdered masterbatch at -85 to -70°C is carried out in a liquid nitrogen tunnel.

10. The method for preparing the sunscreen powder according to claim 8, characterized in that: The drying is vacuum freeze drying.

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