A water-resistant powder compact and a method of making the same

Abstract

The present application relates to the field of cosmetic technology, and more particularly to a waterproof powder compact, which comprises a core layer, a wrapping layer and a stacking layer; the core layer comprises 67.5-93.5 parts of a basic powder treated by a strong hydrophobic surface, the basic powder comprising micron-sized flaky inorganic filler powder; the wrapping layer is wrapped on the outside of the core layer, and comprises 2-8 parts of an emollient and 2-6 parts of a hydrophobic occlusive agent; the stacking layer is attached to the outer surface of the wrapping layer, and comprises 2-24 parts of surface filler powder and 0.5 parts of an antioxidant, the surface filler powder being in the form of spherical powder. The present application improves the powder compact by means of three-dimensional stacking to form a three-layer progressive waterproofing, and the prepared powder compact does not contain PFAS substances such as perfluorooctyltriethoxysilane.

Description

Technical Field

[0001] This invention relates to the field of cosmetics technology, and in particular to a waterproof powder compact and its preparation method. Background Technology

[0002] The market for pressed powder products is currently highly competitive with a wide variety of options. Different brands employ different marketing strategies, but generally, the concept of waterproofing is increasingly important in educating consumers about its use. Early waterproof pressed powders could keep water droplets on their surface, while later ones allowed water droplets to roll freely without penetrating. For example, one brand's pressed powder revolutionized the waterproofing concept, demonstrating in its promotional video that the powder remained dry even after being placed directly under a high-speed stream of water. In recent years, some contract manufacturers have further refined the waterproofing concept by demonstrating exceptional performance in basic powder processing technology.

[0003] However, existing pressed powders require perfluorooctyltriethoxyoctylsilane (PFOTS) as a treatment agent during the manufacturing process to achieve complete waterproofing. The core principle is that PFOTS forms a strong, dense, superhydrophobic and oleophobic protective film on the surface of powder particles, thus achieving a waterproof effect. PFOTS and other PFAS (per- and polyfluoroalkyl substances) may have adverse effects on human health. These compounds are not easily degraded in the environment and can accumulate in the human body, soil, and water. Long-term exposure to these compounds may lead to kidney and liver damage, affect the immune system, and even harm the reproductive system, especially for women, as long-term exposure to these chemicals may lead to decreased fertility and reproductive health problems. Furthermore, PFOTS also pollutes the environment during production and use. Due to its persistence and stability, it may persist in the environment for a long time, posing a potential threat to ecosystems. Therefore, consumers should be vigilant when using cosmetics containing PFOTS and carefully check the product's ingredient list.

[0004] Although perfluorooctyltriethoxysilanes are still widely used in cosmetics, as awareness of their potential hazards deepens, more alternatives or regulations restricting their use may emerge in the future. Therefore, achieving higher levels of water resistance in pressed powder products without using fluorosilane compounds that are harmful to humans and the environment is a problem that this application urgently aims to solve. Summary of the Invention

[0005] To address the shortcomings of the existing technology, this invention provides a waterproof face powder and its preparation method, thereby solving the technical problem that existing waterproof face powders contain fluorinated silane compounds that are unfriendly to human health and the environment.

[0006] This invention provides a waterproof powder compact, comprising the following raw material components in parts by weight:

[0007] The core layer comprises 67.5-93.5 parts of a base powder that has undergone strong hydrophobic surface treatment, wherein the base powder comprises micron-sized flake-shaped inorganic filler powder.

[0008] A coating layer is wrapped around the outer surface of the core layer, and the coating layer includes 2-8 parts of emollient and 2-6 parts of hydrophobic occlusive agent;

[0009] A stacked layer is deposited on the outer surface of the encapsulation layer. The stacked layer includes 2-24 parts of surface-filling powder and 0.5 parts of antioxidant. The surface-filling powder includes at least one nano-sized hydrophobically treated spherical powder.

[0010] In some embodiments of this application, the core layer is composed of mica with a strongly hydrophobic surface treatment and talc powder with a strongly hydrophobic surface treatment in a weight ratio of 1:(1.98-3.5). The base powder, i.e., the micron-sized flake-shaped inorganic filler powder, is composed of mica and talc powder.

[0011] In some embodiments of this application, the base powder with a strongly hydrophobic surface treatment includes micron-sized flake-shaped inorganic filler powder, triethoxysilyl ethyl polydimethylsiloxane, and anhydrous ethanol.

[0012] In some embodiments of this application, the amount of the triethoxysilyl ethyl polydimethylsiloxane used in the preparation of the base powder with a strong hydrophobic surface treatment is 1-5%.

[0013] In some embodiments of this application, the amount of the triethoxysilyl ethyl polydimethylsiloxane used in the preparation of the base powder with a strongly hydrophobic surface treatment is 3%.

[0014] In some embodiments of this application, the amount of the sheet-like inorganic filler powder used in the preparation of the base powder with a strongly hydrophobic surface treatment is 80-90%.

[0015] In some embodiments of this application, the anhydrous ethanol is used in the base powder at a rate of 5-15%.

[0016] In some embodiments of this application, the anhydrous ethanol is used in the base powder at a rate of 10%.

[0017] In some embodiments of this application, the preparation method of the base powder with a strongly hydrophobic surface treatment includes the following steps:

[0018] Step S1: High-pressure hydraulic peeling is used on the sheet-like inorganic filler powder to remove impurities therein;

[0019] Step S2: The sheet-like inorganic filler powder that has undergone the peeling process in step S1 is further ground using a grinding column for 6 hours;

[0020] Step S3: The powder obtained in step S2 is subjected to sedimentation and classification to obtain powder of the required specifications.

[0021] Step S4: Place the powder slurry obtained from sedimentation and classification in step S3 into a grinding jar and continue grinding with grinding balls for 6 hours.

[0022] Step S5: Mix and disperse triethoxysilyl ethyl polydimethylsiloxane with anhydrous ethanol according to the ratio, add the powder obtained in step S4, and continue stirring and mixing for 2 hours.

[0023] Step S6: Dry the mixture obtained in step S5 at 120°C for 5 hours;

[0024] Step S7: The powder obtained from drying in step S6 is sieved through a 180-mesh sieve to obtain the base powder with strong hydrophobic surface treatment.

[0025] In some embodiments of this application, the sedimentation and grading method of step S3 is as follows: first, after 1 hour of sedimentation, a first layer with an average particle size of 15 μm or more is separated; the second sedimentation is 6 hours to obtain powder with an average particle size of 10 μm; and then after a third sedimentation of 24 hours, powder with an average particle size of 5 μm is obtained.

[0026] In some embodiments of this application, the volatility of the powder after drying in step S6 must be less than 3%.

[0027] In some embodiments of this application, the emollient includes polydimethylsiloxane and caprylic / capric triglyceride.

[0028] In some embodiments of this application, the sealing agent includes liquid paraffin and / or petrolatum.

[0029] In some embodiments of this application, the ratio of the emollient to the occlusive agent is in the range of 1:3-4:1.

[0030] In some embodiments of this application, the ratio of the emollient to the occlusive agent is 2:1.

[0031] In some embodiments of this application, the surface-filling powder comprises nylon-12 and silica surface-treated with triethoxyoctylsilane.

[0032] In some embodiments of the present application, the surface filling powder consists of 1-18 parts of nylon-12 and 1-6 parts of silica surface-treated with triethoxyoctylsilane.

[0033] In some embodiments of the present application, the antioxidant includes p-hydroxyacetophenone and raspberry ketone.

[0034] In some embodiments of the present application, the present application also provides a method for preparing a waterproof powder cake, specifically including the following steps:

[0035] (1) Prepare the core layer: Mix the base powder body surface-treated with strong hydrophobicity evenly.

[0036] (2) Prepare the coating layer: Mix the emollient and the sealant evenly.

[0037] (3) Stir the core layer prepared in step (1) at high speed, and then spray the coating layer grease body prepared in step (2) onto the core layer in a high-pressure spraying manner to make it fully mixed and evenly dispersed.

[0038] (4) Put all the raw materials of the stacked layer into the mixture in step (3), and continue to stir to make it fully mixed and evenly dispersed.

[0039] (5) Take out the mixed material obtained in step (4) from the pot, after sieving, perform pressing, and then obtain the waterproof powder cake without fluorine-silicon treatment.

[0040] In some embodiments of the present application, in step (3), the stirring speed is 3000-6000 r / min; the conditions for high-pressure spraying are a temperature of 40 °C, a pressure of 0.4 MPa, a spraying port with a wide angle of 120°, and a pore diameter of 2.4 mm.

[0041] In some embodiments of the present application, in step (4), the stirring speed is 2000-4000 r / min, and the stirring time is 1-5 min.

[0042] In some embodiments of the present application, in step (5), the pressing mold used is an iron plate with a diameter of 58 mm, and the downward pressing pressure is 40 kg / cm 2 ; Through the drop test, it is qualified if the powder cake does not break after dropping from a height of 30 cm onto the marble tabletop 3 times.

[0043] Based on the above technical solution, the powder compact of this application does not contain PFAS substances such as perfluorooctyltriethoxysilane. This application utilizes a three-dimensional stacking method to improve the powder compact by forming a three-layer progressive waterproofing, mainly by constructing a micro-nano papillary three-dimensional composite structure that mimics the "lotus leaf effect," enabling the powder compact to achieve superhydrophobicity as a whole. This structure has micron-sized sheet-like powder as the core, coated with a waxy layer, and then the outermost layer is attached with nano-sized spherical powder. This composite system can effectively reduce the contact area between water droplets and the powder substrate, thereby achieving excellent hydrophobic effects. Attached Figure Description

[0044] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0045] Figure 1 Contact angle test images for evaluating the surface hydrophobicity of the powder sample prepared in Example 1;

[0046] Figure 2 Contact angle test images for evaluating the surface hydrophobicity of the powder sample prepared in Example 2;

[0047] Figure 3 Contact angle test images for evaluating the surface hydrophobicity of the powder sample prepared in Example 3;

[0048] Figure 4 Contact angle test images for evaluating the surface hydrophobicity of the powder sample prepared in Example 4;

[0049] Figure 5 Contact angle test images for evaluating the surface hydrophobicity of the powder sample prepared in Comparative Example 1;

[0050] Figure 6 Contact angle test images for evaluating the surface hydrophobicity of the powder sample prepared in Comparative Example 2;

[0051] Figure 7 Contact angle test images for evaluating the surface hydrophobicity of the powder sample prepared in Comparative Example 3;

[0052] Figure 8 Contact angle test images for evaluating the surface hydrophobicity of the powder sample prepared in Comparative Example 4;

[0053] Figure 9 Contact angle test images for evaluating the surface hydrophobicity of the powder sample prepared in Comparative Example 5;

[0054] Figure 10 Contact angle test images for evaluating the surface hydrophobicity of the powder sample prepared in Comparative Example 6;

[0055] Figure 11 The soaking conditions and contact angle test results of the powder compacts in Examples 1-4 and Comparative Examples 1-6 are shown.

[0056] Figure 12 The drop test results are for the pressed powders of Examples 1-4 and Comparative Examples 1-6;

[0057] Figure 13 The results of stability tests for the pressed powders in Examples 1-4 and Comparative Examples 1-6 are shown.

[0058] Figure 14 The oil absorption value test results are for the pressed powders in Examples 1-4 and Comparative Examples 1-6.

[0059] Figure 15 The results of patch tests for the powder compacts in Examples 1-4 and Comparative Examples 1-6 are shown.

[0060] Figure 16 The results of the makeup effect evaluation test for the powder compacts in Examples 1-4 and Comparative Examples 1-6 are shown.

[0061] Figure 17 The results of texture analysis using the VISA skin analyzer before makeup application;

[0062] Figure 18 The texture map results of the powder sample prepared in Example 1 after makeup application were obtained using a VISA skin analyzer. Detailed Implementation

[0063] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] This invention provides a waterproof powder compact, comprising the following raw material components in parts by weight:

[0065] The core layer consists of 67.5-93.5 parts of base powder with a strongly hydrophobic surface treatment, which includes micron-sized flake-shaped inorganic filler powder.

[0066] The encapsulation layer is wrapped around the outside of the core layer. The encapsulation layer includes 2-8 parts of emollient and 2-6 parts of hydrophobic occlusive agent.

[0067] A stacked layer is deposited on the outer surface of the encapsulation layer. The stacked layer includes 2-24 parts of surface filler powder and 0.5 parts of antioxidant. The surface filler powder is at least one nano-sized hydrophobic spherical powder.

[0068] To achieve overall superhydrophobicity of the powder compact, this application designs and constructs a micro / nano composite papillary structure based on the biomimetic principle of the "lotus effect." This structure uses micron-sized sheet-like powder as a framework, with a waxy functional layer and nano-sized spherical powder sequentially coated on the surface, forming a three-dimensional biomimetic surface with graded roughness. This structure effectively simulates the micro / nano papillary features of a lotus leaf surface through the orderly composite of micron-sized sheets and nanospheres. Its mechanism lies in constructing a composite contact interface on the powder surface that can trap air, thereby significantly reducing the actual contact area and interfacial adhesion energy between water droplets and the powder substrate, thus inducing a superhydrophobic effect.

[0069] This application achieves systematic waterproofing and structural reinforcement through a three-layer progressive structure. The core layer constructs a strongly hydrophobic (water-repellent) substrate on the powder surface through chemical anchoring. The encapsulation layer forms a continuous oil film composed of a combination of emollients and occlusive agents, achieving physical water blocking and water retention. The stacking layer uses nano-spherical powder to fill the gaps between layers, enhancing overall structural stability, preventing clumping and collapse, and simultaneously optimizing the skin feel. Based on the synergistic effect of these multiple mechanisms, the powder compact prepared in this application achieves stable and long-lasting superhydrophobic properties while also possessing excellent structural integrity and user experience.

[0070] In some preferred embodiments, the base powder with a strongly hydrophobic surface treatment also includes triethoxysilyl ethyl polydimethylsiloxane and anhydrous ethanol.

[0071] In some preferred embodiments, the amount of triethoxysilyl ethyl polydimethylsiloxane used in the preparation of the base powder with a strongly hydrophobic surface treatment is 1-5%. In this application, triethoxysilyl ethyl polydimethylsiloxane is used to treat the sheet-like inorganic filler powder. The terminal triethoxysilyl groups can hydrolyze and form strong covalent bonds with the hydroxyl groups on the surface of the sheet-like inorganic filler powder, thereby firmly "grafting" the entire molecule onto the powder particles. This forms a low surface energy silica film on the surface of the powder particles, resulting in a high water contact angle and long-lasting water repellency. Furthermore, as a macromolecular block copolymer, triethoxysilyl ethyl polydimethylsiloxane can provide significant steric hindrance. Using it to hydrophobically treat the sheet-like inorganic filler powder can also effectively reduce the aggregation and adhesion between powder particles.

[0072] In some preferred embodiments, the amount of triethoxysilyl ethyl polydimethylsiloxane used in the preparation of the base powder with a strongly hydrophobic surface treatment is 3%. If the proportion of triethoxysilyl ethyl polydimethylsiloxane is too low, it will lead to insufficient coating of the flake-like inorganic filler powder, resulting in a significant reduction in hydrophobicity; if the proportion is too high, it will lead to excessive powder adhesion, which will easily cause agglomeration during the production process and affect the skin feel of the product.

[0073] In some preferred embodiments, the amount of sheet-like inorganic filler powder used in the preparation of the base powder with a strongly hydrophobic surface treatment is 80-90%.

[0074] In some preferred embodiments, the amount of sheet-like inorganic filler powder used in the preparation of the base powder with a strongly hydrophobic surface treatment is more preferably 87%.

[0075] In some preferred embodiments, the sheet-like inorganic filler powder is mica or talc, that is, the core layer is composed of mica with a strong hydrophobic surface treatment and talc with a strong hydrophobic surface treatment, and the ratio of the mica with a strong hydrophobic surface treatment to the talc with a strong hydrophobic surface treatment is 1: (1.98-3.5).

[0076] This application preferably uses sheet-like inorganic filler powder as the base powder, which is more conducive to constructing a continuous and dense hydrophobic functional layer compared to spherical or needle-like powders. During film formation, the sheet-like powder tends to align and stack layer by layer along the substrate surface under shear force or surface tension, forming a highly ordered barrier similar to a "tile structure". This structure can achieve maximum coverage of the substrate with minimal overlap, providing a dense physical barrier. When media such as water, oxygen and corrosive ions pass through, they must tortuously travel between the sheet-like particles, and the permeation path is significantly extended, thereby greatly improving the barrier efficiency of the film. Furthermore, the hydrophobically modified sheet-like powder can form a uniform low surface energy platform on the surface, laying the foundation for a continuous hydrophobic interface. At the same time, its sheet-like morphology itself constitutes a micron-level rough structure, which can serve as an ideal framework for constructing a lotus leaf-like multi-level roughness, facilitating the attachment of nano-hydrophobic particles (such as silica) on its surface to form a stable composite micro-nano biomimetic structure. Its construction efficiency and structural stability are superior to smooth or spherical substrates. In addition, the film layer formed by the stacking of sheet-like particles has a stronger mechanical interlocking effect, which helps to reduce film defects caused by external forces such as scratching and thermal stress, thereby ensuring the long-lasting reliability of hydrophobic performance.

[0077] The core framework of this application is composed of mica with a strong hydrophobic surface treatment and talc powder with a strong hydrophobic surface treatment in a ratio of 1: (1.98-3.5). The aim is to construct a more stable and efficient "lotus leaf"-like micro-nano hierarchical hydrophobic structure through the synergy of the two in terms of scale and morphology. Compared to single powders, this application synergistically constructs a hierarchical rough framework. Large-sized mica sheets serve as the primary micron-sized framework, mimicking the "main papillae" on the surface of a lotus leaf, providing structural support and air trapping space. Small-sized talc powder acts as a secondary rough unit, its sheet-like morphology and surface micro-undulations forming submicron / nano-level secondary rough features on the mica surface and in the gaps, jointly constructing a complete micro-nano composite hydrophobic interface. Talc powder is precisely filled into the gaps between mica sheets in the specified proportion to achieve the densest spatial packing, reduce structural defects, and make the biomimetic papilla array more complete and dense, thereby significantly enhancing the stability of the air layer and the continuity of the barrier. This composite structure, by synergistically reducing the solid-liquid contact area and extending the medium penetration path, fundamentally strengthens the "lotus leaf effect." The complementarity of the two in terms of mechanical enhancement, surface lubrication, and cost control further improves the overall performance and process feasibility of the system.

[0078] In some preferred embodiments, anhydrous ethanol is used in the base powder at a rate of 5-15%.

[0079] In some preferred embodiments, anhydrous ethanol accounts for 10% of the base powder. Too low a proportion of anhydrous ethanol in the base powder results in insufficient wetting of the system, easily leading to inadequate contact between triethoxysilyl ethyl polydimethylsiloxane and the inorganic filler powder, resulting in a significant reduction in hydrophobicity; too high a proportion leads to raw material waste and increases energy consumption in the subsequent drying process. In this application, the appropriate amount of anhydrous ethanol ensures that triethoxysilyl ethyl polydimethylsiloxane can be efficiently, uniformly, and stably chemically bonded to the surface of the inorganic filler powder, thereby giving the powder excellent durability, water resistance, and a silky smooth feel.

[0080] In some preferred embodiments, the preparation method of the base powder with a strongly hydrophobic surface treatment includes the following steps:

[0081] Step S1: High-pressure hydraulic peeling is used on the flake-shaped inorganic filler powder to remove impurities.

[0082] Step S2: The sheet-like inorganic filler powder that has undergone the sheeting process in step S1 is further ground using a grinding column for 6 hours.

[0083] Step S3: The powder obtained in step S2 is subjected to sedimentation classification to obtain powder of the required specifications.

[0084] Step S4: Place the powder slurry obtained from sedimentation and classification in step S3 into a grinding jar and continue grinding for 6 hours using grinding balls. The sedimentation and classification method is as follows: first, after 1 hour of sedimentation, the first layer with an average particle size of 15 μm or more is separated; the second sedimentation is 6 hours to obtain powder with an average particle size of 10 μm; and then the third sedimentation is 24 hours to obtain powder with an average particle size of 5 μm.

[0085] Step S5: Mix and disperse triethoxysilyl ethyl polydimethylsiloxane with anhydrous ethanol according to the ratio, add the powder obtained in step S4, and continue stirring and mixing for 2 hours.

[0086] Step S6: Dry the mixture obtained in step S5 at 120°C for 5 hours. The volatility of the dried powder must be less than 3%. This step requires strict control of volatility to ensure that the volatile substances (anhydrous ethanol) in the powder are basically vaporized at high temperature and removed from the system.

[0087] Step S7: The powder obtained from drying in step S6 is sieved through a 180-mesh sieve to obtain a base powder with a strongly hydrophobic surface treatment.

[0088] In some preferred embodiments, the emollient includes polydimethylsiloxane and caprylic / capric triglycerides. The choice of emollient allows for penetration and plasticization of the film formed by the blocking agent, resulting in better flexibility and extensibility.

[0089] In some preferred embodiments, the sealing agent includes liquid paraffin and / or petrolatum. Liquid paraffin is a long-chain saturated alkane with a large molecular weight, low polarity, and insoluble in water. It can quickly spread on the skin surface to form a continuous, non-permeable oil film with superior sealing strength compared to lanolin, shea butter, etc. Petrolatum (i.e., petrolatum) has semi-solid hydrocarbon chains that can form a "poreless barrier," effectively blocking the evaporation path of water molecules and simultaneously isolating external stimuli. It is also highly inert and not absorbed or metabolized by the skin. This application utilizes the strong hydrophobicity, high adhesion, and large molecular weight of liquid paraffin and petrolatum to form a dense, strong, and highly continuous physical sealing film. This film forms the basic framework for waterproofing and sweatproofing, providing a strong isolation barrier and significantly enhancing the primary micron-scale framework structure of the core layer, thereby strengthening the hydrophobic effect.

[0090] In some preferred embodiments, the ratio of emollient to occlusive agent ranges from 1:3 to 4:1. The occlusive agent acts like the "steel bars" in a building, providing a strong framework and barrier, while the emollient acts like "concrete," filling and imparting flexibility and plasticity. This dual-oil system better wets and encapsulates the powder, improving the compatibility between the powder and the skin's stratum corneum, resulting in a longer-lasting and more adherent makeup look, reducing powderiness. Furthermore, the dual-oil system forms a more uniform and less defective continuous film. The emollient helps the occlusive agent disperse and encapsulate the powder more evenly, resulting in a more continuous oil film with fewer pores. This directly enhances the integrity of the barrier, making it more difficult for water and sweat to penetrate. The flexible composite film is also more resistant to daily friction (such as touching and wiping) than a single brittle film, meaning that waterproof makeup is less likely to be damaged by external forces and has a longer lasting effect.

[0091] In some preferred embodiments, the ratio of emollient to occlusive agent is 2:1. Too much occlusive agent may result in a film that is too hard and heavy, leading to a stiff powder, difficulty in powder application, and a mask-like finish. Too much emollient, on the other hand, will result in insufficient film strength, reduced waterproof durability, and a powder that is too soft and brittle. This ratio ensures that the encapsulation layer has both sufficient "skeleton" to support its waterproof sealing properties and sufficient "flesh" to provide good application and adherence, achieving an ideal balance between the structural strength and smoothness of the encapsulation layer. This further endows the powder with excellent durability, waterproofness, and a silky smooth feel.

[0092] In some preferred embodiments, the surface-filling powder comprises nylon-12 and silica surface-treated with triethoxyoctylsilane. In this application, the hydrophobically treated nanoscale spherical silica, through precise construction of a nanoscale rough surface structure, directly simulates the nanocrystalline characteristics of lotus leaf surfaces. This significantly reduces the solid-liquid contact area and enhances air layer stability, thus providing crucial assurance for the core hydrophobic performance. Together with the core layer's lamellar skeleton and the encapsulating oil phase, it constructs a durable and complete superhydrophobic system. Nylon-12 primarily serves to adjust the skin feel and workability. Its excellent smoothness and spreadability effectively improve the uniformity of powder distribution on the skin surface, giving the product a silky, refreshing final feel, and avoiding the coating stickiness or grime problems that often occur with highly hydrophobic systems. Therefore, silica ensures the achievement of superhydrophobic performance from a mechanistic perspective, while nylon-12 enhances the user experience and compatibility from an application perspective. The synergistic combination of the two significantly enhances the product's practicality and user acceptance while ensuring excellent hydrophobic performance.

[0093] In some preferred embodiments, the antioxidants include p-hydroxyacetophenone and raspberry ketone. This application does not employ a traditional preservative system, but instead uses a combination of p-hydroxyacetophenone and raspberry ketone, both recognized for their safety. Through antioxidant action, this combination breaks the chain reaction of oil rancidity, preventing product deterioration at its source. Simultaneously, its inherent antibacterial properties meet the product's preservation requirements. This system eliminates users' concerns about traditional preservatives, making it particularly suitable for markets with sensitive skin and those seeking pure formulas. The "coating layer" of the product in this application consists of emollients and occlusive agents, rich in oils. The combination of p-hydroxyacetophenone and raspberry ketone effectively scavenge free radicals, significantly delaying oil oxidation and preventing discoloration, off-flavors, and texture deterioration caused by oxidation. This largely ensures the stability and safety of the product's performance and appearance throughout its entire lifecycle.

[0094] The preparation method of the above-mentioned waterproof powder compact specifically includes the following steps:

[0095] (1) Preparation of core layer: The base powder with strong hydrophobic surface treatment is mixed and dispersed at high speed to obtain a uniform mixed powder;

[0096] (2) Preparation of the coating layer: Mix the emollient and the blocking agent evenly. Disperse and dilute the blocking agent to achieve a lower viscosity and more thorough contact with the core layer, thereby improving the hydrophobicity of the powder.

[0097] (3) The core layer prepared in step (1) is stirred at high speed, with a stirring speed of 3000-6000 r / min, preferably 4000 r / min; then the coating layer grease material prepared in step (2) is sprayed onto the core layer by high-pressure spraying to ensure thorough mixing and uniform dispersion. The conditions for high-pressure spraying are a temperature of 40℃, a pressure of 0.4 MPa, a spray nozzle with a wide angle of 120°, and a hole diameter of 2.4 mm. The stirring speed is controlled to achieve a better mixing effect; the control of the high-pressure spraying conditions can atomize the coating layer grease material into extremely fine and uniform droplets. The fine droplets can make more thorough contact with the high-speed moving core layer units to ensure that the core layer units are uniformly wetted and coated by the treatment agent without sticking together, so as to form an effective seal for the core layer units.

[0098] (4) Add all the raw materials of the stacked layer into the mixture of step (3) and continue stirring to ensure thorough mixing and uniform dispersion. The stirring speed is 2000-4000 r / min and the stirring time is 1-5 min. The preferred stirring speed is 3000 r / min and the stirring time is 3 min.

[0099] (5) The mixture obtained in step (4) is discharged from the pot, sieved, and then pressed to obtain a waterproof powder cake treated with fluorine-free silicone. A 58mm diameter iron disc is used as the pressing mold, and the pressing pressure is 40kg / cm². 2 .

[0100] In subsequent embodiments, a base powder with a strongly hydrophobic surface treatment was prepared using 87% flake-shaped inorganic filler powder, 3% triethoxysilyl ethyl polydimethylsiloxane, and 10% anhydrous ethanol. To more clearly and thoroughly describe the waterproof powder cake and its preparation method provided in the embodiments of the present invention, specific embodiments will be described below.

[0101] Example 1

[0102] A waterproof pressed powder, prepared as follows:

[0103] (1) Preparation of core layer: Take 60.5 parts of talc powder with strong hydrophobic surface treatment and 20 parts of mica with strong hydrophobic surface treatment; mix and disperse at high speed to obtain uniform core layer mixed powder.

[0104] (2) Preparation of coating layer: Take 2 parts of caprylic / capric triglyceride, 2 parts of polydimethylsiloxane and 2 parts of liquid paraffin, and mix them thoroughly to obtain the coating layer oil material.

[0105] The prepared core layer mixed powder was stirred at a high speed of 3000 r / min. While maintaining high-speed stirring, the prepared coating layer oil material was sprayed onto the core layer mixed powder by high-pressure spraying to ensure thorough mixing and uniform dispersion. The high-pressure spraying conditions were: temperature 40℃, pressure 0.4MPa, spray nozzle with a wide angle of 120° and a hole diameter of 2.4mm.

[0106] (3) Preparation of stacked layers: Take 10 parts of nylon-12, 3 parts of silica treated with triethoxyoctylsilane, 0.2 parts of p-hydroxyacetophenone, and 0.3 parts of raspberry ketone, and put them into a pot that has been pre-mixed and dispersed with the coating layer and core layer mixture. Continue stirring to make it fully mixed and evenly dispersed. The stirring speed is 2000 r / min and the stirring time is 5 min.

[0107] (4) Preparation of finished product: After the mixture obtained in the previous step is discharged from the pot and sieved through a 150-mesh screen, it is pressed using a 58mm diameter iron disc with a pressing pressure of 40kg / cm. 2 After pressing, a waterproof powder compact is obtained.

[0108] Example 2

[0109] A waterproof pressed powder, prepared as follows:

[0110] (1) Preparation of core layer: Take 49.5 parts of talc powder with strong hydrophobic surface treatment and 25 parts of mica with strong hydrophobic surface treatment; mix and disperse at high speed to obtain uniform core layer mixed powder.

[0111] (2) Preparation of coating layer: Take 4 parts of caprylic / capric triglyceride, 4 parts of polydimethylsiloxane and 2 parts of petrolatum, and mix them thoroughly to obtain the coating layer oil material.

[0112] The prepared core layer mixed powder was stirred at a high speed of 3000 r / min. While maintaining high-speed stirring, the prepared coating layer oil material was sprayed onto the core layer mixed powder by high-pressure spraying to ensure thorough mixing and uniform dispersion. The high-pressure spraying conditions were: temperature 40℃, pressure 0.4MPa, spray nozzle with a wide angle of 120° and a hole diameter of 2.4mm.

[0113] (3) Preparation of stacked layers: Take 10 parts of nylon-12, 5 parts of silica treated with triethoxyoctylsilane, 0.2 parts of p-hydroxyacetophenone, and 0.3 parts of raspberry ketone, and put them into a pot containing a pre-mixed and dispersed mixture of the coating layer and the core layer. Continue stirring to ensure that the mixture is fully mixed and evenly dispersed. The stirring speed is 2000 r / min and the stirring time is 5 min.

[0114] (4) Preparation of finished product: After the mixture obtained in the previous step is discharged from the pot and sieved through a 150-mesh screen, it is pressed using a 58mm diameter iron disc with a pressing pressure of 40kg / cm. 2 After pressing, a waterproof powder compact is obtained.

[0115] Example 3

[0116] A waterproof pressed powder, prepared as follows:

[0117] (1) Preparation of core layer: Take 68.5 parts of talc powder with strong hydrophobic surface treatment and 25 parts of mica with strong hydrophobic surface treatment; mix and disperse at high speed to obtain uniform core layer mixed powder.

[0118] (2) Preparation of coating layer: Take 1 part of caprylic / capric triglyceride, 1 part of polydimethylsiloxane and 2 parts of petrolatum, and mix them thoroughly to obtain the coating layer oil material.

[0119] The prepared core layer mixed powder was stirred at a high speed of 3000 r / min. While maintaining high-speed stirring, the prepared coating layer oil material was sprayed onto the core layer mixed powder by high-pressure spraying to ensure thorough mixing and uniform dispersion. The high-pressure spraying conditions were: temperature 40℃, pressure 0.4MPa, spray nozzle with a wide angle of 120° and a hole diameter of 2.4mm.

[0120] (3) Preparation of stacked layers: Take 1 part of nylon-12, 1 part of silica treated with triethoxyoctylsilane, 0.2 parts of p-hydroxyacetophenone, and 0.3 parts of raspberry ketone, and put them into a pot containing a pre-mixed and dispersed mixture of the coating layer and the core layer. Continue stirring to ensure that the mixture is fully mixed and evenly dispersed. The stirring speed is 2000 r / min and the stirring time is 5 min.

[0121] (4) Preparation of finished product: After the mixture obtained in the previous step is discharged from the pot and sieved through a 150-mesh screen, it is pressed using a 58mm diameter iron disc with a pressing pressure of 40kg / cm. 2 After pressing, a waterproof powder compact is obtained.

[0122] Example 4

[0123] A waterproof pressed powder, prepared as follows:

[0124] (1) Preparation of core layer: Take 52.5 parts of talc powder with strong hydrophobic surface treatment and 15 parts of mica with strong hydrophobic surface treatment; mix and disperse at high speed to obtain uniform core layer mixed powder.

[0125] (2) Preparation of coating layer: Take 1 part of caprylic / capric triglyceride, 1 part of polydimethylsiloxane, 3 parts of liquid paraffin and 3 parts of petrolatum, and mix them thoroughly to obtain the coating layer oil material.

[0126] The prepared core layer mixed powder was stirred at a high speed of 3000 r / min. While maintaining high-speed stirring, the prepared coating layer oil material was sprayed onto the core layer mixed powder by high-pressure spraying to ensure thorough mixing and uniform dispersion. The high-pressure spraying conditions were: temperature 40℃, pressure 0.4MPa, spray nozzle with a wide angle of 120° and a hole diameter of 2.4mm.

[0127] (3) Preparation of stacked layers: Take 18 parts of nylon-12, 6 parts of silica treated with triethoxyoctylsilane, 0.2 parts of p-hydroxyacetophenone, and 0.3 parts of raspberry ketone, and put them into a pot containing a pre-mixed and dispersed mixture of the coating layer and the core layer. Continue stirring to ensure that the mixture is fully mixed and evenly dispersed. The stirring speed is 2000 r / min and the stirring time is 5 min.

[0128] (4) Preparation of finished product: After the mixture obtained in the previous step is discharged from the pot and sieved through a 150-mesh screen, it is pressed using a 58mm diameter iron disc with a pressing pressure of 40kg / cm. 2 After pressing, a waterproof powder compact is obtained.

[0129] Comparative Example 1

[0130] The raw material composition and addition amount of Comparative Example 1 are the same as those of Example 1. The difference lies in the preparation method of the powder cake in Comparative Example 1. Specifically, in Comparative Example 1, all the core layer raw materials and stacked layer raw materials are put into a grinding pot and mixed and dispersed evenly to obtain a mixture. The oily raw materials of the coating layer are sprayed into the above mixture by high-pressure spraying, and then sieved and pressed to obtain a powder cake. The spraying, sieving and pressing conditions of Comparative Example 1 are the same as those of Example 1.

[0131] Comparative Example 2

[0132] Unlike Example 1, the base powder (flaky inorganic filler powder) in Comparative Example 2 was treated with commercially available common triethoxyoctylsilane. The other raw material composition, dosage, and preparation method of Comparative Example 2 were the same as in Example 1.

[0133] Comparative Example 3

[0134] Unlike Example 1, the amount of the base powder component with strong hydrophobic surface treatment in Comparative Example 3 was reduced to 50.5 parts (specifically, 35.5 parts of talc powder with strong hydrophobic surface treatment and 15 parts of mica powder with strong hydrophobic surface treatment), the amount of oil in the coating layer was increased to 9 parts (3 parts of caprylic / capric triglyceride, 3 parts of polydimethylsiloxane, and 3 parts of liquid paraffin), the amount of nylon-12 was increased to 30 parts, the amount of triethoxyoctylsilane surface-treated silica was increased to 10 parts, and the composition and content of the preservatives were the same as in Example 1.

[0135] Comparative Example 4

[0136] Unlike Example 1, the total amount of flaky inorganic filler powder components added to the powder cake in Comparative Example 4 remained unchanged, but the ratio of mica powder with strong hydrophobic surface treatment to talc powder with strong hydrophobic surface treatment was increased to 1:1. The other raw material composition, addition amount and preparation method of Comparative Example 4 were the same as those in Example 1.

[0137] Comparative Example 5

[0138] Unlike Example 1, the total amount of the base powder with a strongly hydrophobic surface treatment in Comparative Example 5 remained the same, but only talc powder with a strongly hydrophobic surface treatment was used. The other raw material composition, addition amount, and preparation method of Comparative Example 5 were the same as those in Example 1.

[0139] Comparative Example 6

[0140] Unlike Example 1, the amount of sealing agent added to the coating layer of Comparative Example 6 was 0 parts, while the total amount of oil in the coating layer remained unchanged at 6 parts, but only emollients were used (specifically, 3 parts of caprylic / capric triglyceride and 3 parts of polydimethylsiloxane). The other raw material composition, addition amount, and preparation method of Comparative Example 6 were the same as those of Example 1.

[0141] Performance Detection

[0142] 1. Product Drop Test

[0143] For the compacted powder cakes, take 5 samples from each of the examples and comparative examples, and conduct a drop test on a drop table. The height is 30 cm, and the samples are dropped onto a marble tabletop, repeating 3 times. If the number of damaged powder cakes in each group is ≤ 1, it is considered passed; otherwise, it is not passed. The test results are as Figure 12 shown.

[0144] As Figure 12 can be seen, the powder cakes compacted from the powder blocks of Examples 1-4 and Comparative Examples 1-6 all meet the drop requirements, can be fixed in shape and can be used normally, rather than being prone to breakage, looseness, etc. It meets the basic requirements for a powder cake.

[0145] 2. Product Stability Test

[0146] For the compacted powder cakes, place 2 samples from each of the examples and comparative examples under each test condition, and test them at -18°C, 5°C, and 45°C for 3 months. Record one cycle when alternating between -18°C and 40°C for 24 hours, and repeat the cycle 7 times. Finally, after returning to room temperature, if the powder cakes show no changes and can be used normally, it is considered compliant with the regulations, i.e., qualified. If the powder cakes have cracks, fall off, or cannot be used normally, they are considered unqualified. The test results are as Figure 13 shown.

[0147] As Figure 13 can be seen, when conducting stability tests on the powder cakes of Examples 1-4 and Comparative Examples 1-6, they pass the tests under each temperature test condition, the powder cakes can be used normally, and no cracks, fall off, etc. occur. It meets the basic requirements for a powder cake.

[0148] 3. Product Oil Absorption Performance Test

[0149] Dissolve commercially available standard artificial sebum into a liquid state in a 40°C constant temperature water bath. Put 5 g of the sample powder materials of each of the examples and comparative examples into 10 100 mL beakers respectively, and continue to place them in the water bath for constant temperature. Slowly titrate the liquid artificial sebum into the powder, while stirring synchronously. Record the weight m of the consumed artificial sebum when the powder forms lumps, which is the oil absorption value of the product. The test results are as Figure 14 shown.

[0150] As Figure 14It can be seen that the oil absorption values ​​of the pressed powders in Examples 1-4 and Comparative Examples 1-6 are roughly the same, mainly due to the influence of the oil-absorbing component silica and the amount of oil added in the formula. The powder processing method and manufacturing process have relatively little impact. The pressed powders in Examples 1-4 have an oil absorption value of 3.3-4.4g, while the comparative examples have an oil absorption value of 3.5-5.2g. Comparative Example 3 has the highest oil absorption value, reaching 5.2, due to its higher silica content. This range is roughly equivalent to the oil absorption values ​​of commercially available pressed powder products, meeting consumers' needs for oil absorption in pressed powders.

[0151] 4. Product hydrophobicity test

[0152] The pressed powder blocks, samples from the examples and comparative examples were subjected to hydrophobicity tests, and the testing methods are as follows:

[0153] Hydrophobicity Test 1: The powder compacts obtained in the examples and comparative examples were soaked in deionized water at 20-25℃ for 48 hours. The soaked samples were then visually inspected to check for surface integrity, water stains, and water absorption. The test results are shown in Table 4.

[0154] Hydrophobicity Test 2: The hydrophobicity of the powder compact sample surface was evaluated using an optical contact angle meter (model HSD-705B, Dongguan Huishida Instrument Co., Ltd.). The instrument used a static drop method at room temperature (23 °C) and relative humidity (50 %RH) to drop 2 µL of deionized water onto the sample surface. A high-resolution CCD was used to capture the droplet profile in real time, and the Young-Laplace fitting was used to calculate the contact angles on both sides. The average value was taken as the final result. Based on the wetting boundary, θ = 90° is the dividing line between wetting and non-wetting: when θ < 90°, the surface can be spread by water, and the smaller θ is, the better the wetting; when θ > 90°, the water droplet tends to maintain a spherical shape, and the surface exhibits hydrophobic characteristics; θ close to 0° represents complete wetting. Therefore, the change in contact angle can quantitatively characterize the enhancement or weakening of the waterproof performance of the sample surface after different treatments. Images of the contact angle test are attached to the instruction manual. Figure 1-10 As shown, the contact angle measurement value is CA-AV. The test results are summarized as follows: Figure 11 As shown.

[0155] Depend on Figure 11 As can be seen, the powder compacts in Examples 1-4 were soaked well, the surface of the powder block was intact, there were no water stains, and there was no water absorption. The contact angle test showed that the value was basically around 150°, exhibiting obvious hydrophobic properties.

[0156] Comparative Example 1 used the same raw materials and component ratios as the Example, but changed the production method, resulting in a weakening of waterproof performance and a corresponding decrease in the contact angle value. This indicates that the application of three-dimensional stacking technology in this powder product improved its waterproof performance.

[0157] Comparative Example 2 used commercially available ordinary surface treatment powder, which significantly reduced the waterproofing ability and made it impossible to achieve immersion waterproofing. Therefore, the strong hydrophobicity of the surface treatment powder using triethoxysilyl ethyl polydimethylsiloxane is effective.

[0158] Comparative Example 3 reduced the content of the core layer powder in the strong hydrophobic surface treatment to 50.5% and added a large amount of stacking layer raw materials to the formula. Although each powder raw material is waterproof on its own, it cannot support the core skeleton structure of the three-dimensional stacking technology, resulting in the destruction of waterproof performance.

[0159] Comparative Example 4 significantly increased the mica content in the formula and found that even with mica with a strong hydrophobic surface treatment, the high addition amount in the formula had a significant impact on the hydrophobic properties, resulting in a substantial reduction in the waterproof effect of the formula.

[0160] Comparative Example 5 removed the highly hydrophobic surface-treated mica and used talc powder for the entire core layer. The waterproof effect met the requirements and achieved a completely waterproof effect. This is because the proportion of the core layer was high enough and the hydrophobic properties of talc powder itself were good enough. However, using only talc powder would make the product feel too hard and lack a silky smooth feel.

[0161] Comparative Example 6 investigated the effect of the sealing agent on hydrophobic properties and found that without adding the sealing agent oil, and replacing it entirely with the emollient oil, the hydrophobic properties would be weakened, and the composition of the surface coating layer would lead to a reduction in the waterproof effect.

[0162] 5. Product safety patch test

[0163] The examples and comparative samples underwent drop tests, stability tests, anti-corrosion challenge tests, and eye irritation tests, respectively. After passing all tests, volunteers were recruited to conduct patch tests. The specific procedures are as follows:

[0164] Thirty-three people (15 men and 18 women) were selected, aged 18 to 60, with specific criteria in accordance with the Declaration of Helsinki and ICH-GCP requirements.

[0165] Patch testing was conducted as follows: 0.2g of the sample and comparative samples were applied to the inner forearm, covering an area of ​​2cm x 2cm. Skin reactions were recorded after 0.5h, 24h, and 48h. The test results are as follows: Figure 15 As shown.

[0166] Depend on Figure 15It can be seen that none of the 33 people tested had an allergic reaction to the powder compacts of Examples 1-4 and Comparative Examples 1-6. The product is suitable for most consumers because the raw materials of this product comply with the national cosmetic raw material usage catalog and the content meets the requirements. The ingredients are safe and reliable, and the product stability test, preservative challenge test, and eye irritation test have been conducted and passed in the early stage. The patch test of the powder compacts of Examples 1-4 and Comparative Examples 1-6 passed without adverse reactions.

[0167] 6. Product sensory evaluation test

[0168] After the example and comparative samples passed drop tests, stability tests, corrosion resistance tests, eye irritation tests, and patch tests, and assuming product safety was confirmed, a public opinion survey method was used to recruit volunteers to conduct sensory evaluations of the products. The specific procedures are as follows:

[0169] Skin feel: Twenty healthy female volunteers aged 20-40 years with oily or combination skin were selected and randomly divided into two groups of 10 each. The skin feel of the powder compacts from the example and the comparative example were tested.

[0170] Each participant applied equal amounts of powder to both their left and right cheeks. Participants evaluated the application process and the results (after 6 hours) based on the following criteria and scoring standards:

[0171] Makeup adherence to the skin: This refers to the degree to which the makeup remains intact after application: 1 point for severe caking and poor adherence to the skin; 5 points for no caking and good adherence to the skin.

[0172] Matte soft focus: refers to the ability to conceal skin imperfections after application: pores are prominent, poor soft focus, scored as 1 point; all pores are concealed, strong soft focus, scored as 5 points.

[0173] Oil control and makeup staying power: refers to the ability of the makeup to resist sweat and oil after use: poor oil control and makeup staying power is scored as 1 point; good oil control and makeup staying power is scored as 5 points.

[0174] Powder fly rate: refers to the degree of powder fly-off during use: very much powder fly-off, producing powder dust, is scored as 1 point; no powder fly-off, producing no powder dust, is scored as 5 points.

[0175] Makeup effect liking: refers to the overall evaluation of the product after use: 1 point: very poor makeup effect, recorded as 1 point; very good makeup effect, recorded as 5 points.

[0176] Testers scored according to the above criteria, and the average of all scores was calculated. The test results are as follows: Figure 16 As shown.

[0177] Depend on Figure 16It can be seen that the makeup effect evaluation scores of the powder compacts in Examples 1-4 all remained between 4.5 and 5.0, which are relatively high, reflecting the volunteers' high level of satisfaction with the makeup application of the powder compacts. Among them, Example 1 had the highest comprehensive score across all dimensions, meeting the requirements for daily use of the powder compact product. At the same time, the various performance tests of Example 1 also met the requirements, achieving waterproof performance.

[0178] Comparative Example 1, produced using a standard process, resulted in a lower powder quality, leading to a decrease in volunteer makeup application scores of approximately 0.5 points, demonstrating the impact of the manufacturing process on the product. Comparative Example 2, using powder with a standard surface treatment, showed a significant difference in powder quality, resulting in a substantial drop in scores to around 1.5 points. Comparative Example 3, adjusting the content of mica and talc in the core layer formula, reduced the powder's skin feel, affecting the user experience, and further lowered the score to around 3.0. Comparative Example 4, increasing the proportion of mica in the core layer, benefited from the soft, skin-adhering feel of mica, resulting in a higher score of around 4.3 in volunteer testing. Comparative Example 5, removing mica and using only talc, resulted in a harder powder texture, unsuitable for normal use, and a poor user experience, leading to the lowest overall score of around 2.5. Comparative Example 6, using only moisturizing oils instead of occlusive oils, had minimal impact on skin feel and makeup effect, achieving a score of around 4.5.

[0179] Based on comprehensive data analysis, combining powder performance data and makeup effect evaluation scores from volunteers, Example 1 utilizes a highly hydrophobic surface-treated powder, manufactured using a three-dimensional stacking technology, and combined with specific component ratios to ultimately create this powder product, achieving excellent overall performance. Finally, texture mapping was performed using a VISA skin analyzer before and after makeup application using the Example 1 powder, and the results are as follows... Figure 17 and Figure 18 As shown. Figure 17 The pre-makeup blank texture image shows a lot of bumps and depressions, while Figure 18 The texture diagram after makeup application shows that the powder prepared in Example 1 can significantly reduce the skin texture effect, indicating that the skin has a good plumpness and smoothness, and the makeup smoothness is also very high.

[0180] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0181] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A waterproof powder compact, characterized in that, The raw material components include the following parts by weight: The core layer comprises 67.5-93.5 parts of a base powder that has undergone strong hydrophobic surface treatment, wherein the base powder comprises micron-sized flake-shaped inorganic filler powder. A coating layer is wrapped around the outer surface of the core layer, and the coating layer includes 2-8 parts of emollient and 2-6 parts of hydrophobic occlusive agent; A stacked layer is deposited on the outer surface of the encapsulation layer. The stacked layer includes 2-24 parts of surface-filling powder and 0.5 parts of antioxidant. The surface-filling powder includes at least one nano-sized hydrophobically treated spherical powder.

2. The waterproof powder compact according to claim 1, characterized in that: The base powder with a strongly hydrophobic surface treatment includes micron-sized flake-shaped inorganic filler powder, triethoxysilyl ethyl polydimethylsiloxane, and anhydrous ethanol.

3. The waterproof powder compact according to claim 2, characterized in that: The preparation method of the base powder with strong hydrophobic surface treatment includes the following steps: Step S1: High-pressure hydraulic peeling is used on the sheet-like inorganic filler powder to remove impurities therein; Step S2: The sheet-like inorganic filler powder that has undergone the peeling process in step S1 is further ground using a grinding column for 6 hours; Step S3: The powder obtained in step S2 is subjected to sedimentation classification to obtain powder of the required specifications. Step S4: Place the powder slurry obtained from sedimentation and classification in step S3 into a grinding jar and continue grinding with grinding balls for 6 hours. Step S5: Mix and disperse triethoxysilyl ethyl polydimethylsiloxane with anhydrous ethanol according to the ratio, add the powder obtained in step S4, and continue stirring and mixing for 2 hours. Step S6: Dry the mixture obtained in step S5 at 120°C for 5 hours; Step S7: The powder obtained from drying in step S6 is sieved through a 180-mesh sieve to obtain the base powder with strong hydrophobic surface treatment.

4. The waterproof powder compact according to claim 3, characterized in that: The sedimentation and classification method in step S3 is as follows: first, after 1 hour of sedimentation, the first layer with an average particle size of more than 15 μm is separated; the second sedimentation is 6 hours to obtain powder with an average particle size of 10 μm; and then after a third sedimentation of 24 hours, powder with an average particle size of 5 μm is obtained.

5. The waterproof powder compact according to claim 1, characterized in that: The emollients include polydimethylsiloxane and caprylic / capric triglycerides.

6. The waterproof powder compact according to claim 1, characterized in that: The sealing agent includes liquid paraffin and / or petrolatum.

7. The waterproof powder compact according to claim 1, characterized in that: The ratio of the emollient to the occlusive agent is in the range of 1:3-4:

1.

8. The waterproof powder compact according to claim 1, characterized in that, The surface-filling powder comprises nylon-12 and silica surface-treated with triethoxyoctylsilane.

9. The waterproof powder compact according to claim 1, characterized in that: The antioxidants include p-hydroxyacetophenone and raspberry ketone.

10. A method for preparing a waterproof face powder according to any one of claims 1-9, characterized in that, Specifically, the following steps are included: (1) Preparation of core layer: The base powder that has been treated with strong hydrophobic surface is mixed evenly; (2) Preparation of the coating layer: Mix the emollient and the occlusive agent evenly; (3) Stir the core layer prepared in step (1) at high speed, and then spray the coating oil material prepared in step (2) onto the core layer by high pressure spraying to ensure thorough mixing and uniform dispersion; (4) Add all the raw materials of the stacked layer into the mixture of step (3) and continue stirring to ensure thorough mixing and uniform dispersion; (5) The mixture obtained in step (4) is discharged from the pot, sieved, and then pressed to obtain the waterproof powder cake.

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