Preparation method for powdery cosmetic product having color gradient effect, and powdery cosmetic product

Abstract

A preparation method for a powdery cosmetic product having a color gradient effect, and a powdery cosmetic product. The preparation method comprises: mixing materials; distributing colors: providing a mold provided with at least one upwardly open chamber; taking at least one water-soluble pigment and diluting the pigment to obtain at least one pigment solution, and dot-applying the at least one pigment solution to at least one predetermined position at the bottom of the chamber; filling; freezing: freezing the material body in the mold at low temperature to obtain a powder material master product; demolding: separating the powder material master product from the mold; and drying: drying the demolded powder material master product to obtain the powdery cosmetic product having a color gradient effect. The mass percentage concentration of the pigment solution is 0.1% to 10%, and the viscosity of the mixed material body at 25 °C is 1000-15,000 cP. The prepared powdery cosmetic product can achieve natural smudging and color gradient effects.

Description

Preparation methods of powder cosmetics with gradient color effects and powder cosmetics

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411763215.9, filed on December 2, 2024, entitled “Preparation method of powder cosmetic with gradient color effect and powder cosmetic”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of daily cosmetic technology, specifically relating to a method for preparing a powder cosmetic with a gradient color effect and the powder cosmetic itself. Background Technology

[0004] Powder cosmetics can enhance facial features and add radiance to the makeup. For example, highlighter can brighten specific areas, improve facial contours, make the base makeup more radiant, eliminate dullness, and create visual contrast between light and shadow to enhance the three-dimensionality of facial features.

[0005] Most of the mixed-color powder cosmetics currently on the market are made by pressing powder, which involves complex manufacturing processes, low production efficiency, and surface colors that are either irregular or have obvious splicing. Summary of the Invention

[0006] In view of this, this application provides a method for preparing a powder cosmetic with a gradient color effect and the powder cosmetic itself, which has a natural gradient blending effect.

[0007] In a first aspect, embodiments of this application provide a method for preparing a powder cosmetic with a gradient color effect, comprising the following steps: mixing: providing raw materials for preparing the powder cosmetic, mixing to obtain a mixed material; coloring: providing a mold, the mold having at least one upward-opening chamber; taking at least one water-soluble pigment, diluting it to obtain at least one pigment solution, and applying the at least one pigment solution to at least one preset position at the bottom of the chamber; filling: filling the mixed material into the mold after coloring according to a preset amount, the water-soluble pigment diffuses directionally within the mixed material under the action of a concentration gradient; freezing: freezing the material in the mold at a low temperature to obtain a powder master product; demolding: separating the powder master product from the mold; drying: drying the demolded powder master product to obtain a powder cosmetic with a gradient color effect; the mass percentage concentration of the pigment solution is 0.1% to 10%, preferably 0.5% to 5%; the viscosity of the mixed material at 25°C is 1000 to 15000 cP, preferably 2000 to 5000 cP.

[0008] According to an embodiment of the first aspect of this application, the mold is made of TPR, TPE, silicone, silicone rubber, rubber or metal; the bottom of the mold cavity may or may not have a three-dimensional pattern.

[0009] According to an embodiment of the first aspect of this application, a gradient color effect is formed on the contact surface between the powder cosmetic and the bottom of the chamber, and extends into the interior of the powder cosmetic.

[0010] According to an embodiment of the first aspect of this application, in the filling step, the mixture is filled into the mold from different directions to control the diffusion direction of the water-soluble pigment.

[0011] According to an embodiment of the first aspect of this application, after the filling step, an auxiliary diffusion step is further included, the auxiliary diffusion step including: baking or microwave heating the mixture in the mold.

[0012] According to an embodiment of the first aspect of this application, the baking temperature is 30-70°C and the baking time is 5 min-1 h; preferably, during the baking, the baking temperature gradually increases from the edge region of the mixture to the center region; more preferably, the baking temperature of the edge region of the mixture is 30-40°C and the baking temperature of the center region of the mixture is 60-70°C.

[0013] According to an embodiment of the first aspect of this application, the power of the microwave heating is 0.2 to 1 GHz, preferably 0.3 to 0.5 GHz; the microwave heating time is 20 s to 5 min, preferably 2 to 3 min.

[0014] According to an embodiment of the first aspect of this application, the step of freezing the material inside the mold at low temperature is carried out in a liquid nitrogen quick-freezing device; preferably, the temperature inside the liquid nitrogen quick-freezing device is -120 to -70°C, more preferably -95 to -80°C.

[0015] According to an embodiment of the first aspect of this application, the liquid nitrogen quick-freezing device is a liquid nitrogen tunnel, and the material passes through the liquid nitrogen tunnel on a conveyor belt at a speed of 0.6 to 1 meter / minute. The powder masterbatch passes through the liquid nitrogen tunnel for 6 to 10 minutes.

[0016] According to an embodiment of the first aspect of this application, drying includes one or more of vacuum drying, freeze drying, microwave drying, and supercritical fluid drying; preferably, the drying is vacuum freeze drying.

[0017] According to an embodiment of the first aspect of this application, the raw materials for preparing powder cosmetics include a powder phase component, an oil phase component, and an aqueous phase component, wherein the raw materials form an oil-in-water emulsion system, wherein:

[0018] Powder components include one or more of fillers and colorants;

[0019] The oil phase components include one or more of the following: emollients, antioxidants, and sunscreens;

[0020] The aqueous phase components include one or more of the following: solvent, thickener, film-forming agent, emulsifier, preservative, and active ingredient.

[0021] Secondly, embodiments of this application provide a powder cosmetic with a gradient color effect, prepared by any of the methods described above; optionally, the powder cosmetic is selected from pressed powder, blush, eyeshadow or highlighter.

[0022] Compared with the prior art, this application has at least the following beneficial effects:

[0023] In the method provided in this application, water is used as a solvent to dissolve water-soluble pigments, forming a pigment solution with good fluidity. The pigment solution is first dotted on the bottom of the mold cavity before the material is filled in. Under the action of the concentration gradient, the pigment diffuses naturally from the high concentration area to the low concentration area, forming a soft transition gradient color effect. When two or more water-soluble pigments are used, the different colors of pigments naturally blend during the diffusion process, forming multi-color blurring and gradation. By adjusting the initial concentration of the pigment solution and the viscosity of the mixed material, the prepared powder cosmetic has a natural gradient blurring effect. Attached Figure Description

[0024] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings, wherein the same or similar reference numerals denote the same or similar features.

[0025] Figure 1 is a schematic diagram of the product of Embodiment 15 provided in this application;

[0026] Figure 2 is a schematic diagram of the product of Embodiment 16 provided in this application. Detailed Implementation

[0027] To make the purpose, technical solution, and beneficial technical effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the embodiments described in this specification are merely for explaining this application and are not intended to limit it.

[0028] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated, just as any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, although not explicitly stated, every point or individual value between the endpoints of the range is included within that range. Therefore, each point or individual value can be used as its own lower or upper limit and combined with any other point or individual value or with other lower or upper limits to form a range not explicitly stated.

[0029] In the description of this application, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, and "multiple" in "one or more" means two or more.

[0030] The foregoing description of this application is not intended to describe every disclosed implementation or method. Instead, the following description provides more specific examples of exemplary embodiments. Throughout the application, guidance is provided through a series of embodiments that can be used in various combinations. The examples listed are representative only and should not be construed as exhaustive.

[0031] Most of the mixed-color and gradient powder cosmetics currently on the market are made by pressing powder, which involves complex manufacturing processes, low production efficiency, and the inability to create a natural gradient blending effect on the surface.

[0032] In view of the above problems, this application provides a method for preparing a powder cosmetic with a gradient color effect and a powder cosmetic with a gradient color effect, which has a natural gradient blending effect, can achieve mass production, and improve production efficiency.

[0033] Preparation of powder cosmetics with gradient color effect

[0034] In a first aspect, embodiments of this application provide a method for preparing a powder cosmetic with a gradient color effect, comprising the following steps: mixing: providing raw materials for preparing the powder cosmetic, mixing to obtain a mixed material; coloring: providing a mold, the mold having at least one upward-opening chamber; taking at least one water-soluble pigment, diluting it to obtain at least one pigment solution, and applying the at least one pigment solution to at least one preset position at the bottom of the chamber; filling: filling the mixed material into the mold after coloring according to a preset amount, the water-soluble pigment diffuses directionally within the mixed material under the action of a concentration gradient; freezing: freezing the material in the mold at a low temperature to obtain a powder master product; demolding: separating the powder master product from the mold; drying: drying the demolded powder master product to obtain a powder cosmetic with a gradient color effect; the mass percentage concentration of the pigment solution is 0.1% to 10%, preferably 0.5% to 5%; the viscosity of the mixed material at 25°C is 1000 to 15000 cP, preferably 2000 to 5000 cP.

[0035] In the mixing step, the raw materials for preparing powder cosmetics with gradient color effects can be commercially available or prepared in-house. It is understood that the raw materials for preparing powder cosmetics with gradient color effects typically include a powder phase component, an oil phase component, and an aqueous phase component. The raw materials can be mixed using various methods commonly used in existing technologies, such as mechanical stirring, by adding the raw materials step by step and mixing them evenly. Homogenization and defoaming operations can be added during the mixing process. Different mixing methods and steps can be used depending on the raw materials, and this application is not limited to these.

[0036] The preparation method provided in this application embodiment involves pre-coating a pigment onto a mold, requiring a mold and a water-soluble pigment solution. The mold must have at least one upward-opening chamber to accommodate the pigment and mixture to be coated. When preparing the water-soluble pigment solution, one or more water-soluble pigments are taken, dissolved, and diluted to obtain one or more pigment solutions. These pigment solutions are then applied to at least one predetermined position at the bottom of the chamber.

[0037] In the preparation of the pigment solution in this application embodiment, the same pigment can be selected and diluted into solutions of multiple concentrations to form a concentration gradient; two or more pigments can be selected and diluted into solutions of different concentrations or into solutions of multiple concentrations to form a concentration gradient; or two or more pigments can be mixed to obtain a new color pigment, and then diluted and applied. The use of various soluble pigments in the prior art is not limited, and can be selected according to the requirements of the gradient color effect.

[0038] This application does not limit the specific color of the water-soluble pigment. For example, the water-soluble pigment can be one or a combination of several of the following commercially available water-soluble pigment products with the following brand names: Red 4 (CI 14700), Red 22 (CI 45380), Red 28 (CI 45410), Red 33 (CI 17200), Red 40 (CI 16035), Carmine (CI 75470), Blue 1 (CI 42090), Yellow 5 (CI 19140), Yellow 6 (CI 15985), Yellow 7 (CI 10316), Yellow 8 (CI 45350), Yellow 10 (CI 47005), Violet 2 (CI 60730), Orange 4 (CI 15510), Green 3 (CI 42053), Green 5 (CI 61570), and Green 8 (CI 59040).

[0039] In this application embodiment, the specific location and number of preset positions are not limited. They can be selected according to the design. For example, the preset positions are evenly distributed around the outer ring of the bottom of the chamber, or evenly distributed on a certain side of the bottom of the chamber, or at a certain fixed point on the bottom of the chamber.

[0040] During the filling process, the preset amount can be set according to the volume of the powder cosmetic, the mold capacity, or the filling requirements. The preset amount can be the same or different each time. After the mixture is filled into the mold after coloring according to the preset amount, the water-soluble pigment will diffuse directionally within the mixture under the action of the concentration gradient.

[0041] In this embodiment, filling can be performed using a conventional filling machine or a pneumatic feeding device. The pneumatic feeding device refers to a device that fills the mold with material using pneumatic pressure. Exemplarily, the pneumatic feeding device may include an air pump and a pipe connected to the air pump. The air pump provides the necessary air pressure for delivery, and the pipe fills the mold with the material. This application is not limited to this. When using a conventional filling machine, the material is filled under gravity. When the material's flowability meets the requirements, filling can be performed at room temperature; when it is desired to improve the material's flowability, the material can be appropriately heated.

[0042] For powder cosmetics with gradient color effects that create intricate embossed designs, using a pneumatic feeding device for filling is a superior method. The material is filled into the mold in a preset amount via the pneumatic feeding device. The pressure assists in filling the material to the sharp corners of the intricate embossed design. Even if the material has a high viscosity, it can still fill the sharp corners of the intricate embossed design well and achieve good density, solving the problems of air bubbles and softness in the finished product.

[0043] Specifically, the mixture can be pressed into the mold by air pressure. For example, a pneumatic feeding device includes a feed pipe, an air pump, and a discharge pipe. The air pump provides the conveying air pressure to draw the mixture into the pneumatic feeding device through the feed pipe and then press it into the mold through the discharge pipe. Alternatively, the mixture can be drawn into the mold by air pressure. For example, the pneumatic feeding device is connected to the mold, and the pneumatic feeding device provides the conveying air pressure to draw the mixture into the mold. In some embodiments, the pressure in the pneumatic feeding device is 0.01–0.06 MPa, or 0.02–0.04 MPa.

[0044] After the filling step, a solvent removal step is also required. Through processes such as freeze drying, the solvent is removed from the powder cosmetics. The solvent content in the final powder cosmetics generally needs to be controlled below 5%.

[0045] In the method provided in this application, water is used as a solvent to dissolve water-soluble pigments to form a pigment solution with good fluidity. The pigment solution is first applied to the bottom of the mold cavity before the material is filled in. Under the action of the concentration gradient, the pigments diffuse naturally from the high concentration area to the low concentration area, forming a soft transition gradient color effect. When two or more water-soluble pigments are used, the pigments of different colors naturally merge during the diffusion process, forming multi-color shading and gradient.

[0046] This application utilizes the diffusion of water-soluble pigments within a mixture to achieve natural blending and gradient color effects. The initial concentration of the pigment solution and the viscosity of the mixture are key parameters. On one hand, the mixture needs to have an appropriate viscosity suitable for the diffusion of water-soluble pigments. If the viscosity is too high, the diffusion of pigments is hindered, and the gradient rendering effect is not obvious; if the viscosity is too low, the pigments diffuse excessively within the mixture, also failing to create a natural gradient blending effect. On the other hand, the pigment solution needs to have an initial concentration suitable for diffusion within the mixture. If the initial concentration of the pigment solution is too low, the diffusion effect is not obvious, and the blending effect cannot be achieved; if the initial concentration of the pigment solution is too high, pigment accumulation occurs locally within the mixture, resulting in an uneven surface after drying.

[0047] In this embodiment, by controlling the initial concentration of the pigment solution and the viscosity of the mixture within a certain range, the prepared powder cosmetics have a natural gradient blurring effect. This embodiment is applicable to the preparation of water-in-oil system powder cosmetics.

[0048] For example, the viscosity of the mixture at 25°C is 1000 cP, 2000 cP, 3000 cP, 4000 cP, 5000 cP, 6000 cP, 7000 cP, 8000 cP, 9000 cP, 10000 cP, 11000 cP, 12000 cP, 13000 cP, 14000 cP, 15000 cP, or any two of the above values.

[0049] For example, the mass percentage concentration of the pigment solution is 0.1%, 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 7%, 8%, 9%, 10%, or a range consisting of any two of the above values.

[0050] The preparation method provided in this application is simple in process, gets rid of the complexity of traditional color mixing and powder pressing process, can realize mass production, and improve production efficiency.

[0051] In some embodiments, the mold is made of TPR, TPE, silicone, silicone rubber, rubber or metal; the bottom of the mold cavity may or may not have a three-dimensional pattern.

[0052] The preparation method in this application embodiment can use molds made of TPR, TPE, silicone, silicone rubber, rubber or metal, all of which can produce powder cosmetics with natural gradient color effects.

[0053] The bottom of the cavity of the selected mold can be flat and without a three-dimensional pattern; or the bottom of the cavity of the mold can have a three-dimensional pattern. The three-dimensional pattern can be varied. For example, the three-dimensional pattern can be a deer shape or a wave pattern. The embodiments of this application are not limited to this.

[0054] In some embodiments, a gradient effect is formed on the contact surface between the powder cosmetic and the bottom of the chamber, and extends into the interior of the powder cosmetic.

[0055] When the pigment solution is applied to the bottom of the chamber, the gradient color effect is formed on the contact surface between the powder cosmetic and the bottom of the chamber. Under the action of the concentration gradient, the pigment solution diffuses in the thickness direction of the powder cosmetic, and the gradient color effect extends from the contact surface with the bottom of the chamber in the direction away from the contact surface, that is, into the interior of the powder cosmetic.

[0056] In some embodiments, during the filling step, the mixture is filled into the mold from different directions to control the diffusion direction of the water-soluble pigment.

[0057] The mixture has an impact force when filled, which will drive the diffusion of water-soluble pigments, thereby controlling the diffusion direction of water-soluble pigments. When the mixture is filled into the mold from different directions, the water-soluble pigments will diffuse in different directions, which is conducive to forming a natural gradient dyeing effect.

[0058] In this embodiment of the application, the mixture is filled into the mold from different directions during filling. For example, the mixture is filled along different directions at a preset angle to the plane where the bottom of the mold is located. Preferably, the preset angle is 30° to 90°. For example, the preset angle is 30°, 40°, 45°, 50°, 60°, 70°, 80°, 90° or any range of two of the above values.

[0059] For example, when the preset angle is 90°, the mixture is filled in a direction perpendicular to the plane where the bottom of the mold is located; when the preset angle is 60°, the mixture is filled in a direction inclined to the plane where the bottom of the mold is located.

[0060] In some embodiments, after the filling step, an auxiliary diffusion step is further included, which may include baking the mixture in the mold or microwaving the mixture in the mold.

[0061] This application embodiment adds an auxiliary diffusion step, including baking or microwave heating, after the filling step. On the one hand, baking or microwave heating removes some moisture from the mixture; on the other hand, it promotes the formation of a gradient color effect. After filling, the mixture is in a stable state. During baking or microwave heating, the temperature of the mixture rises, which helps the water-soluble pigments continue to diffuse within the stable mixture, making the gradient effect more natural. Simultaneously, the water-soluble pigments are better adsorbed onto the powder surface in the mixture, making the gradient color effect more stable. This application embodiment, by adding an auxiliary diffusion step after the filling step, can promote a more natural gradient effect.

[0062] The embodiments of this application do not limit the baking temperature and baking time, and can be set as needed. Preferably, the baking temperature is 30-70℃ and the baking time is 5 minutes to 1 hour.

[0063] Baking temperatures in the range of 30 to 70°C make the baking process relatively gentle, allowing moisture to evaporate slowly, which helps improve the uniformity of powder cosmetics and allows water-soluble pigments to diffuse evenly in a stable mixture. For example, the baking temperature is 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, or any two of the above values.

[0064] Baking time within the range of 5 minutes to 1 hour ensures that some of the moisture in the mixture does not evaporate excessively, while also resulting in higher baking efficiency and saving production time. For example, baking time can be 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 1 hour, or any combination of two of the above values.

[0065] Furthermore, in this application, during the directional diffusion of water-soluble pigments within the mixture under the influence of a concentration gradient, the diffusion rate of pigment molecules in the edge region of the mixture may be faster than that in the central region. This may be because pigment molecules in the edge region of the mixture have a lower probability of colliding with each other and thus a faster diffusion rate, while pigment molecules in the central region of the mixture have a higher probability of colliding with each other and thus a slower diffusion rate.

[0066] In some embodiments, baking is used to assist diffusion, with the baking temperature gradually increasing from the edge region to the center of the mixture. For example, the baking temperature at the edge region of the mixture is 30–40°C, and the baking temperature at the center region is 60–70°C. This ensures that the assisted diffusion effect on the center region is greater than that on the edge region, reducing the difference in diffusion rates between the edge and center regions during pigment molecule diffusion.

[0067] In other embodiments, microwave heating is used to assist diffusion. For example, the microwave heating power is 0.2–1 GHz, preferably 0.3–0.5 GHz, and the microwave heating time is 20 s–5 min, preferably 2–3 minutes. For example, the microwave heating power can be 0.2 GHz, 0.3 GHz, 0.4 GHz, 0.5 GHz, 0.6 GHz, 0.7 GHz, 0.8 GHz, 0.9 GHz, 1.0 GHz, or any range of two of the above values. For example, the microwave heating time can be 20 s, 30 s, 40 s, 50 s, 1 min, 1.2 min, 1.4 min, 1.5 min, 1.6 min, 1.8 min, 2 min, 2.5 min, 3 min, 3.5 min, 4 min, 4.5 min, 5 min, or any range of two of the above values.

[0068] Microwave heating exhibits a center effect, meaning that microwaves are reflected within the furnace cavity, with the center being the overlapping region of the microwave field, where microwave energy density is highest, decreasing towards the edges. Therefore, this application utilizes relatively low-power microwave heating to ensure that the mixture is not immediately dried, allowing the central region to receive microwave radiation first, accelerating molecular motion and providing a higher assist for diffusion compared to the edges. Due to these characteristics, microwave heating can achieve assisted diffusion in a shorter time, addressing the issue of pigment molecules diffusing faster at the edges than at the center, minimizing interference factors in the gradient color effect, and resulting in a more natural and gentle gradient.

[0069] In some embodiments, the step of freezing the material inside the mold at low temperature is carried out in a liquid nitrogen quick-freezing device; preferably, the temperature inside the liquid nitrogen quick-freezing device is -120 to -70°C, more preferably -95 to -80°C.

[0070] For example, the liquid nitrogen quick-freezing device can be a liquid nitrogen tunnel, a liquid nitrogen freezer, an ultra-low temperature freezer, etc., and these devices are commercially available, but this application is not limited thereto.

[0071] The raw material components in the mixture undergo molecular rapid freezing at extremely low temperatures in a liquid nitrogen quick-freezing device. The mixture contains components such as oils and emulsions. During its freezing and shaping process, it passes through a maximum ice crystal formation zone, approximately -10 to 0°C, where about 80% of the liquid (water, emulsion, etc.) turns into ice. Unlike conventional freezing performed before demolding in existing technologies, the molecular rapid freezing process in this application, completed within a liquid nitrogen tunnel, allows the powder masterbatch to quickly pass through the maximum ice crystal formation zone. The ice crystals in the powder masterbatch are more fine, uniform, and dense. During subsequent drying, the removal of these fine and uniform ice crystals does not affect the already formed gradient color effect, ensuring a natural, soft, and continuous gradient. This results in a softer, more manageable dimensional variation in the freeze-dried product, a more stable product structure, and better drop resistance.

[0072] In some embodiments, the liquid nitrogen quick-freezing device is a liquid nitrogen tunnel, in which the material passes through the liquid nitrogen tunnel on a conveyor belt at a speed of 0.6 to 1 meter / minute, and the powder masterbatch passes through the liquid nitrogen tunnel for 6 to 10 minutes.

[0073] A liquid nitrogen tunnel, also known as a liquid nitrogen tunnel-type quick-freezing machine, is a device that uses liquid nitrogen as a cold source and adopts a continuous production method. Materials are fed into the quick-freezing tunnel via a conveyor belt to achieve continuous material entry and exit and rapid freezing.

[0074] This application also proposes optimal liquid nitrogen quick-freezing conditions suitable for the preparation of powder cosmetics by studying the freezing curves of powder cosmetic mixtures and the energy transfer characteristics in a liquid nitrogen quick-freezing device. Under these conditions, the liquid nitrogen quick-freezing of the powder masterbatch results in a final powder cosmetic with a uniform and dense texture, optimal skin feel, and optimal product structure stability and drop resistance. The powder masterbatch passes through the liquid nitrogen tunnel on a conveyor belt at a speed of 0.6–1 m / min, and the transit time within the liquid nitrogen tunnel is 6–10 minutes.

[0075] In some embodiments, drying includes one or more of vacuum drying, freeze drying, microwave drying, and supercritical fluid drying; preferably, drying is vacuum freeze drying.

[0076] In this embodiment, the powder masterbatch after demolding is dried using vacuum freeze-drying technology. Freeze-drying involves freezing the water-containing material below its freezing point, causing the water to turn into ice. In a vacuum environment or under high vacuum conditions, the fine and uniformly distributed ice crystals in the powder masterbatch are sublimated into water vapor and removed, thus preserving the raw material's composition, color, and aroma to the greatest extent. The pigments are naturally adsorbed on the powder surface and will not be transferred with the liquid water, thereby ensuring the stable maintenance of the rendering effect throughout the drying process.

[0077] The embodiments of this application can also be dried by vacuum drying, freeze drying, microwave drying and supercritical fluid drying, or by combining multiple of the above drying methods.

[0078] In some embodiments, the raw materials used to prepare powder cosmetics include a powder phase component, an oil phase component, and an aqueous phase component, and the raw materials form an oil-in-water emulsion system, wherein:

[0079] Powder components include one or more of fillers and colorants;

[0080] The oil phase components include one or more of the following: emollients, antioxidants, and sunscreens;

[0081] The aqueous phase components include one or more of the following: solvent, thickener, film-forming agent, emulsifier, preservative, and active ingredient.

[0082] In the embodiments of this application, the raw materials form an oil-in-water emulsion system. The oil-in-water emulsion system uses water as the continuous phase, which allows water-soluble pigments to flow better and the gradient effect to be more natural.

[0083] In some embodiments, the thickener and film-forming agent are selected from natural water-soluble polymers or their derivatives, synthetic water-based polymers or water-based inorganic thickeners;

[0084] The natural water-soluble polymer or its derivatives are selected from at least one of the following: alginic acid, agar, carrageenan, xanthan gum, gellan gum, chondrus crispus, xanthan gum, guar gum, tamarind gum, tara gum, gum arabic, astragalus gum, pectin, arabinogalactan, wheat protein, soybean protein, gelatin, casein, chitosan, condensed polysaccharide, cyclodextrin, hyaluronic acid, konjac gum, tremella polysaccharide, guar gum, microcrystalline cellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, starch phosphate, starch, sodium hydroxymethyl starch, sodium polyacrylate grafted starch, and hydroxypropyl guar gum.

[0085] The synthesized waterborne polymer is selected from at least one of the following: acrylic (ester) / C10-30 alkanol acrylate crosspolymer, carbomer, acrylic (ester) / octylacrylamide copolymer, acrylic (ester) / ethylhexyl acrylate copolymer, sodium acrylate / sodium acryloyldimethyl taurate copolymer, acrylic (ester) / octylacrylamide copolymer, styrene / acrylate copolymer, acrylic (ester) copolymer, hydroxyethyl acrylate / sodium acryloyldimethyl taurate copolymer, polyacrylate crosspolymer-6, acrylic (ester) / stearyl ether-20 methacrylate copolymer, ammonium acryloyldimethyl taurate / behenol ether-25 methacrylate crosspolymer, ammonium acrylic (ester) copolymer, sodium polyacrylate, sodium polyacryloyldimethyl taurate, polyacrylamide, polyvinylpyrrolidone, polyvinyl alcohol, VP / VA copolymer, polyurethane-1, and polyurethane-35.

[0086] The water-based inorganic thickener is selected from at least one of magnesium aluminum silicate, lithium sodium magnesium silicate, lithium magnesium silicate, sodium magnesium silicate, montmorillonite, or their derivatives.

[0087] In some embodiments, the emollient is selected from at least one of alcohols, silicone oils, mineral oils, synthetic oils, animal and vegetable oils or their derivatives;

[0088] The vegetable and animal oils or their derivatives are selected from at least one of glycerol, propylene glycol, dipropylene glycol, pentane glycol, butylene glycol, ethylene glycol, hexanediol, sorbitol, xylitol, polyethylene glycol, polydimethylsiloxane, octyl polymethylsiloxane, phenyl polytrimethylsiloxane, cetyl polydimethylsiloxane, C30-45 alkyl dimethylsilyl polypropylene silsesquioxane, bis-PEG-18 methyl ether dimethylsiloxane, white mineral oil, petrolatum, hydrogenated polyisobutylene, lanolin and its derivatives, octyl dodecanol, caprylic / capric triglyceride, ethylhexyl palmitate, bis-diglycerol polyacryl adipate-2, isononyl isononanoate, jojoba seed oil, coconut oil, hydrogenated coconut oil glycerides, meadowfoam seed oil, olive oil, squalane, C9-12 alkyl, coconut oil alcohol-caprylate / capric ester, tocopheryl acetate, and methyl glucetol polyether-10.

[0089] In some embodiments, the filler is selected from at least one of mica, talc, synthetic fluorophlogopite, kaolin, bentonite, boron nitride, bismuth oxychloride, silica, potassium sodium aluminum silicate, lauroyl lysine, magnesium stearate, magnesium myristate, calcium aluminum borosilicate, tin oxide, calcium sodium borosilicate, aluminum hydroxide, zinc stearate starch and its derivatives, and plastic microbeads.

[0090] In some embodiments, the preservative is selected from at least one of phenoxyethanol, parabens, chlorphenesin, potassium sorbate, sodium benzoate, or preservative synergists.

[0091] The preservative synergist is selected from at least one of caprylyl glycol, p-hydroxyacetophenone, ethylhexylglycerin, 1,2-hexanediol, capryloyl hydroxamic acid, 1,2-pentanediol, glyceryl caprylate, and cymene.

[0092] Secondly, embodiments of this application provide a powder cosmetic with a gradient color effect, prepared by any of the methods described above; optionally, the powder cosmetic is selected from pressed powder, blush or eyeshadow.

[0093] The powder cosmetics prepared in the embodiments of this application have a natural gradient blending effect.

[0094] In some embodiments, the powder cosmetics with a gradient effect are selected from pressed powder, blush, eyeshadow, or highlighter. Powder cosmetics with a gradient effect may also include products with other functions.

[0095] Example

[0096] The following embodiments describe the disclosure of this application in more detail. These embodiments are for illustrative purposes only, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0097] Example 1

[0098] (1) Mixing: The following raw materials are provided: Phase A: water, binder, potassium chloride solution, emulsifier, oil, vitamin E; Phase B: synthetic fluorophlogopite, silica; Phase C: pearlescent agent; Phase D: preservative. The temperature control range of the mixing process is 60-65℃. Phase A is heated, and Phases B, C, and D are added for emulsification and homogenization. The emulsified and homogenized material is then degassed under vacuum to obtain a mixed material with a viscosity of 5000 cP at 25℃, ready for filling.

[0099] (2) Color application: Provide a silicone mold with an upward-opening cavity and an embossed three-dimensional pattern at the bottom of the cavity; dilute water-soluble pigment CI 42090 with water to a pigment solution with a mass percentage concentration of 3%, and apply the pigment solution to the preset positions at the bottom of the cavity of the silicone mold.

[0100] (3) Filling: Fill the mold with the mixture from the center of the mold into the mold after coloring according to the preset amount;

[0101] (4) Freezing: The mold containing the mixture is placed in a freezer at -15°C to freeze, thereby obtaining the powder masterbatch product;

[0102] (5) Demolding: Separating the powder masterbatch from the mold;

[0103] (6) Drying: The powder masterbatch after demolding is baked to obtain powder cosmetics.

[0104] Examples 2-5

[0105] The difference between Examples 2-5 and Example 1 lies in the different mass percentage concentrations of the pigment solution or the different viscosities of the mixture.

[0106] Examples 6-9

[0107] The difference between Examples 6-9 and Example 1 is that, after the filling step, an auxiliary diffusion step was performed on the material inside the mold.

[0108] The auxiliary diffusion step in Example 6 is baking, in which the mixture is baked uniformly at 50°C.

[0109] The auxiliary diffusion step in Example 7 is baking, with the baking temperature gradually increasing from the edge region to the center region of the mixture; the baking temperature of the edge region of the mixture is 30°C, and the baking temperature of the center region of the mixture is 70°C.

[0110] The auxiliary diffusion step in Examples 8 and 9 was microwave heating, with microwave frequencies of 0.3 GHz and 0.5 GHz in the microwave cavity and microwave heating times of 3 min and 2 min, respectively.

[0111] Examples 10-12

[0112] The difference between Examples 10-12 and Example 1 is that the step of freezing the material inside the mold is carried out in a liquid nitrogen tunnel.

[0113] Example 13

[0114] The difference between Example 13 and Example 1 is that the drying step uses vacuum freeze-drying. Specifically, vacuum freeze-drying includes pre-freezing, sublimation drying, and desorption drying. Pre-freezing specifically includes freezing at -40℃ to -50℃ for 0.5h to 2h. Sublimation drying includes first heating to -3℃ to 3℃, wherein the heating process includes several first heating stages and several first holding stages, and the first heating stages and the first holding stages are performed alternately; the first heating stage heats at 0.5 to 1℃ / min for 10 to 20min, and the first holding time is 1.5 to 2h. Desorption drying includes drying at 20℃ to 60℃, wherein the drying process includes several second heating stages and several second holding stages, and the second heating stages and the second holding stages are performed alternately; the second heating stage heats at 0.5 to 1℃ / min for 10 to 20min, and the second holding time is 1.5h to 2h.

[0115] Example 14

[0116] The difference between Example 14 and Example 1 is that, after the filling step, microwave-assisted diffusion was performed on the material inside the mold; the freezing step of the material inside the mold was carried out in a liquid nitrogen tunnel; and the drying step was vacuum freeze-drying, with the specific freeze-drying steps being the same as those in Example 13.

[0117] Example 15

[0118] The difference between Example 15 and Example 1 is that after the filling step, the material in the mold was baked; the freezing step of the material in the mold was carried out in a liquid nitrogen tunnel; the drying step was vacuum freeze-drying, and the specific freeze-drying steps were the same as those in Example 13; in step (2) coloring step, water-soluble pigments CI 19140 and CI 42090 were premixed to obtain the desired color combination pigments, and then diluted with water in different proportions to obtain several pigment solutions of different concentrations. The pigment solutions were then dotted onto the preset positions on the bottom outer periphery of the mold cavity.

[0119] Example 16

[0120] The difference between Example 16 and Example 15 lies in step (2) color application step: dilute water-soluble pigment Cl42090 with water in a certain ratio (blue); dilute water-soluble pigment CI17200 with water in a certain ratio (red); mix water-soluble pigments CI42090 and CI17200 in a certain ratio and then dilute with water (purple); apply the blue and red pigment solutions to the diagonal positions at the bottom of the mold respectively, and apply the purple pigment solution to the other two diagonal positions.

[0121] Comparative Examples 1-6

[0122] The difference between Comparative Example 1 and Example 1 is that, before filling, the mixed material is injected with a pigment solution using a syringe, and then filled.

[0123] The difference between Comparative Example 2 and Example 1 is that, immediately after filling, the pigment solution was injected into the bottom of the mold cavity using a syringe.

[0124] The difference between Comparative Examples 3-6 and Example 1 lies in the concentration of the pigment solution and the viscosity of the mixture.

[0125] The parameters for mixing, coloring, filling and baking, freezing demolding and drying of Examples 1-16 and Comparative Examples 1-6 are shown in Table 1.

[0126] Table 1. Process parameters for Examples 1-16 and Comparative Examples 1-6

[0127] Test section

[0128] Powder compacts were prepared according to the methods of Examples 1-16 and Comparative Examples 1-6, with 100 powder compacts prepared for each example or comparative example, and their appearance and drop tests were performed.

[0129] 1) Visual inspection

[0130] Observe the appearance of the pressed powder with the naked eye or with the aid of a microscope, including the appearance of the gradient effect. The focus is on whether the gradient effect of the pressed powder is natural and even, and the smoothness of the gradient surface.

[0131] The appearance of the powder compacts was based on observations of more than 90% of the 100 compacts tested.

[0132] 2) Drop detection

[0133] Adjust the drop test platform rotation screws to adjust the plate to the 30cm mark; place the powder block face up in the center of the test height.

[0134] The first drop test is performed: Press the test platform button to drop the powder block onto a hard plate. Pick up the powder block after it has fallen onto the platform and check its surface for cracks or breaks. If the powder block is cracked or broken, stop the drop test for that powder block. If the powder block shows no abnormalities, proceed to the second drop test. The procedure for the second drop test is the same as the first drop test. If the powder block is cracked or broken, stop the drop test for that powder block. If the powder block shows no abnormalities, proceed to the third drop test. The procedure for the third drop test is the same as the first drop test.

[0135] The breakage rate for each drop test is the ratio of the number of broken powder compacts to the total number of powder compacts tested in that test. The first, second, and third breakage rates for Examples 1-16 and Comparative Examples 1-6 were recorded respectively. The drop resistance scoring criteria are shown in Table 2.

[0136] Table 2 Drop Resistance Scoring Criteria

[0137] The test results of Examples 1-16 and Comparative Examples 1-6 are recorded in Table 3.

[0138] Table 3. Detection results of Examples 1-16 and Comparative Examples 1-6

[0139] As shown in Table 3, the test results of Examples 1-16, using the preparation method of the powder cosmetic with gradient color effect provided in this application, involved color application, filling the material into the mold, followed by freezing, drying, and demolding to obtain block-shaped powder cosmetics. Compared with Comparative Examples 1-6, which did not use the preparation method of this application, Comparative Examples 1-6 failed to form a gradient color effect, or the color and gradient effect were not obvious. Examples 1-16 showed significant improvements in filling efficiency, the naturalness and uniformity of the gradient color effect, and the smoothness of the gradient color surface. They also had a significant effect in reducing the breakage rate of powder compacts in drop tests.

[0140] In the preparation method of the gradient color-effect powder cosmetic provided in this application, parameters such as the initial concentration of the pigment solution, the viscosity of the mixture, and the temperature and time control for curing the powder masterbatch at low temperatures also affect the technical effect achieved by this application. This application also provides a preferred range of the above process parameters to further improve the various properties of the gradient color-effect powder cosmetic prepared according to the method provided in this application. For example, in Examples 6-9, assisted diffusion after filling results in a larger gradient color range compared to Examples 1-5. In particular, assisted diffusion through gradient baking and microwave heating avoids the phenomenon that pigment molecules diffuse faster at the edges of the material than in the central area during preparation, reducing interference with the gradient effect and making the gradient gradient softer and more natural. In Examples 10-12, ultra-low temperature pre-freezing in a liquid nitrogen tunnel not only creates a gradient color effect but also makes the gradient color more obvious than in Examples 1-5, without color loss after drying. Example 13 uses vacuum freeze-drying including pre-freezing, sublimation drying, and desorption drying, which not only creates a gradient color effect but also makes the gradient color more obvious than in Examples 1-5, without color loss after drying. Examples 14-16 achieve better gradient color effects by adjusting process parameters, reducing interference with the gradient effect, making the gradient gradient softer and more natural, and the color more obvious, without color loss after drying. For the product effect of Example 15, please refer to Figure 1; for the product effect of Example 16, please refer to Figure 2.

[0141] Comparative Examples 1 to 6, which did not use the methods provided in this application to carry out the preparation steps, could not obtain powder cosmetics with gradient color effects.

[0142] In Comparative Example 1, pigment solution was injected into the mixed material using a syringe before filling. While a diffused effect was observed, it failed to create a directional, natural gradient. In Comparative Example 2, pigment solution was immediately injected into the bottom of the mold cavity using a syringe after filling. The pigment only diffused locally, and air was introduced into the material, disrupting its internal density. The finished powder exhibited pores, cracks, and pigment spots, and had poor drop resistance. In Comparative Example 3, the material viscosity was too low, leading to excessive pigment diffusion. In multi-color mixing, this could result in a single color being mixed together. Furthermore, the low viscosity resulted in a soft powder block with poor drop resistance. In Comparative Example 4, the material viscosity was too high, hindering pigment diffusion and resulting in an indistinct rendering effect. In Comparative Example 5, the pigment solution concentration was too low, resulting in an indistinct diffused effect. In Comparative Example 6, the pigment solution concentration was too high, leading to localized pigment accumulation and an uneven surface after drying.

[0143] The above examples 1-16 and comparative examples 1-6 fully demonstrate that the preparation method provided in this application has outstanding beneficial effects and can prepare powder cosmetics with natural blending and gradient color effects.

[0144] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing a powder cosmetic with a gradient color effect, wherein, Includes the following steps: Mixing: Providing raw materials for the preparation of powder cosmetics, mixing them to obtain a mixture; Fabric: Provide a mold having at least one upward-opening chamber; Take at least one water-soluble pigment, dilute it separately to obtain at least one pigment solution, and apply the at least one pigment solution to at least one preset position at the bottom of the chamber respectively; Filling: The mixture is filled into the mold after coloring according to the preset amount, and the water-soluble pigment diffuses directionally in the mixture under the action of the concentration gradient; Freezing: Freezing the material inside the mold at low temperature to obtain powder masterbatch; Demolding: Separating the powder masterbatch from the mold; Drying: The powder masterbatch is dried after demolding to obtain powder cosmetics with gradient color effect; The pigment solution has a mass percentage concentration of 0.1% to 10%, preferably 0.5% to 5%. The viscosity of the mixture at 25°C is 1000–15000 cP, preferably 2000–5000 cP.

2. The method for preparing a powder cosmetic with a gradient color effect according to claim 1, wherein, The mold is made of TPR, TPE, silicone, silicone rubber, rubber or metal; the bottom of the cavity of the mold may or may not have a three-dimensional pattern.

3. The method for preparing a powder cosmetic with a gradient color effect according to claim 1, wherein, The gradient color effect is formed on the contact surface between the powder cosmetic and the bottom of the chamber, and extends into the interior of the powder cosmetic.

4. The method for preparing a powder cosmetic with a gradient color effect according to claim 1, wherein, In the filling step, the mixture is filled into the mold from different directions to control the diffusion direction of the water-soluble pigment.

5. The method for preparing a powder cosmetic with a gradient color effect according to claim 1, wherein, Following the filling step, an auxiliary diffusion step is also included, which includes baking or microwave heating the mixture within the mold.

6. The method for preparing a powder cosmetic with a gradient color effect according to claim 5, wherein, The baking temperature is 30-70°C, and the baking time is 5 min-1 h; preferably, the baking temperature increases gradually from the edge region to the center region of the mixture; more preferably, the baking temperature of the edge region of the mixture is 30-40°C, and the baking temperature of the center region of the mixture is 60-70°C.

7. The method for preparing a powder cosmetic with a gradient color effect according to claim 5, wherein, The microwave heating frequency is 0.2 to 1 GHz, preferably 0.3 to 0.5 GHz; the microwave heating time is 20 seconds to 5 minutes, preferably 2 to 3 minutes.

8. The method for preparing a powder cosmetic with a gradient color effect according to claim 1, wherein, The step of freezing the material inside the mold at low temperature is carried out in a liquid nitrogen quick-freezing device; Preferably, the internal temperature of the liquid nitrogen quick-freezing device is -120℃ to -70℃, and more preferably -95℃ to -80℃.

9. The method for preparing a powder cosmetic with a gradient color effect according to claim 8, wherein, The liquid nitrogen quick-freezing device is a liquid nitrogen tunnel. The material passes through the liquid nitrogen tunnel on a conveyor belt at a speed of 0.6 to 1 meter / minute. The powder masterbatch passes through the liquid nitrogen tunnel for 6 to 10 minutes.

10. The method for preparing a powder cosmetic with a gradient color effect according to claim 1, wherein, The drying process includes one or more of the following: vacuum drying, freeze drying, microwave drying, and supercritical fluid drying; Preferably, the drying is vacuum freeze drying.

11. The method for preparing a powder cosmetic with a gradient color effect according to claim 1, wherein, The raw materials used to prepare powder cosmetics include a powder phase component, an oil phase component, and an aqueous phase component, wherein the raw materials form an oil-in-water emulsion system, wherein: The powder components include one or more of fillers and colorants; The oil phase component includes one or more of the following: skin moisturizers, antioxidants, and sunscreens; The aqueous phase component includes one or more of the following: solvent, thickener, film-forming agent, skin moisturizer, emulsifier, preservative, and active ingredient.

12. A powder cosmetic with a gradient color effect, wherein, Prepared by the method of any one of claims 1-11; optionally, the powder cosmetic is selected from pressed powder, blush, eyeshadow or highlighter.

Images