A powder foundation and a method for preparing the same

Abstract

The application provides a powder foundation and a preparation method thereof, and relates to the field of cosmetics, and comprises the following steps: crushing and mixing a filler, a titanium dioxide colorant, an inorganic colorant, an adsorbent and a film-forming agent, and sieving to obtain a powder phase; adding deionized water and glycerol into a container 1, stirring to form a vortex, keeping the rotating speed, and then adding carbomer 940 powder at the edge of the vortex; after the powder is added, the rotating speed is increased to stir until the powder is completely dispersed; after stirring and swelling, tromethamine solution is added while stirring until a hydrogel is formed; after the gel is formed, the rotating speed is reduced and continuous stirring is performed; butanediol, 1,2 pentanediol and p-hydroxyacetophenone are added into a container 2 and dissolved, and then the hydrogel is added and stirred; the powder phase is added into the container 2, stirred and discharged, and then sieved through a 20-mesh sieve; after sieving, the material is poured into the container 2, stirred, discharged and sieved through a 40-mesh sieve. The application is a two-in-one product of a loose powder and a foundation, and a user can complete the foundation makeup by pressing and applying.

Description

Technical Field

[0001] This invention relates to the field of cosmetic technology, specifically to a powder foundation and its preparation method. Background Technology

[0002] In today's fast-paced life, daily makeup has become an important part of many people's image enhancement and confidence boost. However, the contradiction between the demand for efficient makeup and the cumbersome traditional makeup process is becoming increasingly prominent, providing a broad application space for the introduction of powder-based convertible foundation. Currently, consumers have higher and higher demands for makeup efficiency, especially during busy morning hours, where complicated makeup steps often become a burden. Traditional base makeup routines usually require using foundation separately as a base, followed by setting powder for oil control. These at least two steps are not only time-consuming but also require carrying two different products, which is not user-friendly for those seeking convenience.

[0003] Current mainstream liquid foundations have inherent drawbacks: In terms of texture, they are liquid with high fluidity, making it difficult to precisely control the amount used during application and resulting in waste. Furthermore, in high summer temperatures, liquid foundations are less stable and prone to separation, affecting product quality and performance. Summary of the Invention

[0004] This invention provides a powder foundation and its preparation method to solve at least one of the technical problems mentioned in the background art.

[0005] To address the aforementioned technical problems, this invention discloses a method for preparing powder foundation, comprising the following steps: S1: The filler, titanium dioxide colorant, inorganic colorant, adsorbent, and film-forming agent are placed in a pulverizing device for crushing and mixing, and then sieved to obtain a powder phase; S2: Add deionized water and glycerin to container one, start stirring at 500-800 rpm to form a vortex in the water, and while maintaining the speed, sprinkle carbomer 940 powder into the edge of the vortex. After sprinkling the powder, increase the speed to 1500-2000 rpm and continue stirring until the powder is completely dispersed. After dispersion, continue stirring at 500-800 rpm. After swelling, add tromethorphan solution while stirring until the system forms a hydrogel. After the hydrogel is formed, reduce the speed and continue stirring. S3: Add butanediol, 1,2-pentanediol, and p-hydroxyacetophenone to container two and dissolve them at 60-70℃ to obtain a solution. Add the solution to the hydrogel obtained in S2 and stir to mix. S4: Add the powder obtained in S1 to the material obtained in S3, stir at 700-800 rpm, discharge the material after stirring for the first time, and pass it through a 20-mesh sieve. Pour the material that has passed through a 20-mesh sieve into container two, stir at 700-800 rpm for a second time, then discharge the material and pass it through a 40-mesh sieve.

[0006] Preferably, the raw material composition of the powder foundation comprises, by weight percentage: 5-10% filler, 5-10% titanium dioxide colorant, 1-5% inorganic colorant, 0.5-3% adsorbent, 5-10% film-forming agent, 40-70% deionized water, 1-5% butanediol, 1-5% 1,2-pentanediol, 1-5% glycerin, 0.1-0.5% p-hydroxyacetophenone, 0.05-0.3% carbomer, and 0.02-0.1% tromethamine.

[0007] Preferably, in S1: the rotation speed is 2900 rpm and the screen is a 150 mesh screen.

[0008] Preferably, the adsorbent is silylated silica, the film-forming agent is an acrylate / ethylhexyl acrylate crosslinked polymer, and the tromethamine solution is a 10% (w / w) aqueous solution of tromethamine.

[0009] Preferably, the filler components include: mica, polydimethylsiloxane, and triethoxyoctylsilane.

[0010] Preferably, the components of the titanium dioxide colorant are: titanium dioxide, aluminum hydroxide, and triethoxyoctylsilane.

[0011] Preferably, the inorganic colorant comprises titanium dioxide and zinc oxide.

[0012] Preferably, S2 includes: S2-A: Add deionized water and glycerin to container one, and start stirring at 500-800 rpm to form a vortex in the water. First, sprinkle carbomer 940 powder at the first rate until it reaches 1 / 3 of the total formula weight of carbomer 940 powder, and then sprinkle carbomer 940 powder at the second rate until it reaches the total formula weight of carbomer 940 powder. After the powder is applied, increase the speed to 1500-2000 rpm and continue stirring until the powder is completely dispersed; S2-B: After dispersing S2-A, continue stirring at 500-800 rpm for a preset swelling time, then test the material viscosity. If the viscosity stability requirement is not met within the swelling time, extend the swelling time by 5-10 minutes until the viscosity meets the viscosity stability requirement. When the viscosity stability requirement is met, construct a time-viscosity curve, and determine the actual platform viscosity and effective viscosity change rate based on the time-viscosity curve. An alarm will be triggered if the actual platform viscosity does not meet the required range. S2-C: When S2-B does not alarm, after the viscosity stability requirement is met, the theoretical addition rate of tromethamine solution is determined based on the effective viscosity change rate. Tromethamine solution is added at the theoretical addition rate of tromethamine solution, and the mixture is stirred while adding until the system forms a hydrogel. S2-D: After the hydrogel is formed, continue stirring at 300-500 rpm for 10-15 min.

[0013] The present invention also discloses a powder foundation, which is prepared by the aforementioned method for preparing a powder foundation.

[0014] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This powder foundation, developed using this technology, is a two-in-one product combining loose powder and foundation. It integrates the base makeup and setting steps into one, allowing users to complete their base makeup with a simple pressing and application motion, significantly simplifying the makeup process and perfectly meeting the needs of efficient makeup application. Meanwhile, the poor oil control performance of traditional foundation products has long been a pain point for consumers. Many liquid foundations have an oily texture, causing the skin to quickly become shiny, especially in hot weather or in the T-zone where oil secretion is high. This leads to makeup fading and patchiness within a short time, severely affecting the longevity of the makeup. Even when used with loose powder, the oil control effect of some products is insufficient, requiring frequent touch-ups. This powder foundation, after setting, forms a stable protective film that effectively absorbs excess oil from the skin, fundamentally solving the problem of traditional foundation products' lack of oil control. This allows the makeup to remain fresh and clean for a long time, further enhancing the product's practicality and competitiveness in everyday makeup scenarios.

[0016] In terms of concealing power, conventional liquid foundations vary in their performance. For deeper acne scars, blemishes, and other imperfections, multiple layers are often required to achieve a good coverage effect, but this can easily lead to a heavy makeup look and make the skin appear unnatural. The powder foundation of this application, after transforming into a liquid form, can closely adhere to the skin texture and has excellent coverage for various imperfections. A single layer is sufficient to effectively cover most imperfections, achieving a lightweight yet highly concealing makeup effect.

[0017] Long-lasting makeup is also crucial. Regular liquid foundations tend to smudge and become patchy over time due to factors like sebum production and sweating, especially in oily areas like the T-zone, where the makeup's effectiveness often diminishes after just a few hours. This product, however, has a strong powdery feel and forms a protective film on the skin after application, effectively resisting oil and sweat, maintaining the integrity and longevity of the makeup, keeping it clean and fresh all day long.

[0018] In terms of makeup finish, even if regular liquid foundation is advertised as lightweight, it can still feel somewhat oily in actual use, especially for people with oily skin, which can increase the burden on the skin and make it look greasy. This powder foundation, when transformed into a liquid form, presents a natural powdery finish that is refreshing and non-greasy, making the skin look more delicate, soft, and sophisticated.

[0019] When stored in powder form, it is less affected by temperature and humidity (no separation after 3 months of storage at 40℃), solving the problem of liquid foundation deterioration in summer; when used, it transforms through hydrogel to adapt to different skin conditions (dry / oily / combination skin). Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0021] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0022] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions and features of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] The present invention provides the following embodiments: Example 1: This embodiment of the invention provides a method for preparing powder foundation, such as... Figure 1 As shown, it includes the following steps: S1: The filler, titanium dioxide colorant, inorganic colorant, adsorbent, and film-forming agent are placed in a pulverizing device for crushing and mixing, and then sieved to obtain a powder phase; S2: Add deionized water and glycerin to container one, start stirring at 500-800 rpm to form a vortex in the water, and while maintaining the speed, sprinkle carbomer 940 powder into the edge of the vortex. After sprinkling the powder, increase the speed to 1500-2000 rpm and continue stirring until the powder is completely dispersed. After dispersion, continue stirring at 500-800 rpm. After swelling, add tromethorphan solution while stirring until the system forms a hydrogel. After the hydrogel is formed, reduce the speed and continue stirring. S3: Add butanediol, 1,2-pentanediol, and p-hydroxyacetophenone to container two and dissolve them at 60-70℃ to obtain a solution. Add the solution to the hydrogel obtained in S2 and stir to mix. S4: Add the powder obtained in S1 to the material obtained in S3, stir at 700-800 rpm, discharge the material after stirring for the first time, and pass it through a 20-mesh sieve. Pour the material that has passed through a 20-mesh sieve into container two, stir at 700-800 rpm for a second time, then discharge and pass through a 40-mesh sieve. Both the first and second time periods can be 3 minutes.

[0024] The powder foundation contains the following raw materials by weight percentage: 5-10% filler, 5-10% titanium dioxide colorant, 1-5% inorganic colorant, 0.5-3% adsorbent, 5-10% film-forming agent, 40-70% deionized water, 1-5% butanediol, 1-5% 1,2-pentanediol, 1-5% glycerin, 0.1-0.5% p-hydroxyacetophenone, 0.05-0.3% carbomer, and 0.02-0.1% tromethamine.

[0025] In S1, the rotation speed is 2900 rpm and the screen is a 150-mesh screen.

[0026] The adsorbent is silylated silica, the film-forming agent is an acrylate / ethylhexyl acrylate crosslinked polymer, and the tromethamine solution is a 10% (w / w) aqueous solution of tromethamine.

[0027] The filler components include mica, polydimethylsiloxane, and triethoxyoctylsilane. Specifically, the filler is mica modified with modifiers (polydimethylsiloxane and triethoxyoctylsilane).

[0028] The titanium dioxide colorant comprises: titanium dioxide, aluminum hydroxide, and triethoxyoctylsilane. The titanium dioxide colorant is obtained by surface treatment of titanium dioxide with aluminum hydroxide and triethoxyoctylsilane. The inorganic colorant comprises titanium dioxide and zinc oxide. The inorganic colorant is obtained by surface treatment of titanium dioxide and zinc oxide with surface treatment agents (aluminum hydroxide, stearic acid, polydimethylsiloxane alcohol). In this invention, the titanium dioxide is ultrafine hydrophobic titanium dioxide, and the zinc oxide is ultrafine hydrophobic zinc oxide. Specific implementation examples: Table 1. Raw material composition and dosage of powder foundation

[0030] ①Put phases 1, 2, 3, 4, and 5 (refer to phases 1-12 in the table above, which are referred to as phases 1-12 here) into a grinding pot and grind them evenly. Stir evenly at a speed of 2900 rpm and pass them through a 150-mesh sieve for later use. ② Add phase 6 (deionized water) and phase 9 (glycerol) to container one, and start stirring (first stir at a low speed of 500-800 rpm to create a vortex and avoid powder splashing); slowly and evenly sprinkle carbomer 940 powder into the edge of the vortex, ensuring the powder is quickly wetted by the water and avoiding accumulation on the water surface or container walls; after sprinkling the powder, increase the stirring speed to medium-high speed (1500-2000 rpm) and continue stirring for 10-15 minutes until the powder is completely dispersed and the system is a uniform, low-viscosity liquid (without obvious particles or lumps). Principle: Carbomer powder swells rapidly upon contact with water. If the dispersion is uneven, the agglomerated powder will form a tight "shell," preventing the interior from contacting the water and resulting in incomplete swelling. Swelling and Defoaming: After dispersion, continue stirring at low speed (500-800 rpm) for 30-60 minutes to allow the carbomer molecules to fully absorb water and swell (at this time, the viscosity of the system will increase slightly, but the thickening effect will not be achieved); if a large number of air bubbles are introduced during dispersion, let it stand for 15-30 minutes (or vacuum defoaming) to avoid the air bubbles affecting the subsequent neutralization step. After dispersion, add phase 12: tromethamine (prepared as a 10% aqueous solution and added slowly), stirring continuously until the system forms a gel. At this point, the stirring speed should be reduced (300-500 rpm) to avoid damaging the three-dimensional network structure. ③ Dissolve the following components in container 2 (which can be a beaker): phase 7 (butanediol), phase 8 (1,2-pentanediol), and phase 10 (p-hydroxyacetophenone) at 60-70°C. Add the solution to the dispersed hydrogel and stir until homogeneous. The stirring speed can be 500-800 rpm. ④ Slowly add the pulverized powder to the hydrogel, using a four-blade agitator at 700-800 rpm for 3 minutes, then discharge. Pass the mixture through a 20-mesh sieve, then pour it into container two, using a four-blade agitator at 700-800 rpm for 3 minutes; discharge again, and pass the mixture through a 40-mesh sieve. (For the first sieving, choose a larger mesh size to ensure the powder completely coats the water; the second sieving will allow the powder to largely coat the water). The functions of each component in this invention are as follows: 1. Ultrafine hydrophobic titanium dioxide: In powder foundation, it not only provides excellent UV protection (preventing makeup from dulling due to UV exposure), but its ultrafine particle size also improves the adhesion to the skin, avoiding the roughness of traditional powders; the hydrophobic modification reduces the mixing with skin oils, delaying makeup fading, while enhancing the dispersion stability in thickened hydrogels to ensure an even makeup effect.

[0031] 2. Ultrafine hydrophobic zinc oxide: As a multifunctional component, it has both antibacterial properties (reducing skin inflammation caused by makeup clogging) and UV protection (supplementing UVA protection blind spots). Its hydrophobicity works synergistically with titanium dioxide to reduce the affinity between powder and skin oil, thus prolonging makeup wear time. The ultrafine particle size also enhances concealing power while avoiding a heavy makeup feel.

[0032] 3. Silylated silica powder: After silylation modification, its hydrophobicity matches the powder composition. Its porous structure can absorb excess oil from the skin (solving the problem of oiliness in the T-zone), while also serving as a "skeleton" to support the distribution of titanium dioxide and zinc oxide, preventing powder sedimentation. In addition, the smooth properties of silica can improve the smoothness of application and reduce powder caking.

[0033] 4. Thickening hydrogel: plays a key role in the form-transformation medium in powder foundation: it is stored in powder form when dry, and when it comes into contact with skin moisture or a small amount of water, the hydrogel swells and encapsulates the powder to form a uniform film (achieving the unique texture of "powder to liquid"); its three-dimensional network structure fixes the powder and prevents fallout, while providing moderate moisturization, balancing the dryness of hydrophobic powder, and making the makeup adhere better.

[0034] 5. Acrylic (ester)-based / ethylhexyl acrylate crosspolymer (film-forming agent): As the core of the film reinforcement in the system, it has excellent film-forming properties and flexibility. After contact with the skin, it can quickly form a continuous and breathable film, firmly locking the ultrafine hydrophobic powder and thickening hydrogel onto the skin surface. Its water resistance and oil resistance are outstanding, which can resist the erosion of the film by sweat and oil. At the same time, the elasticity of the film can stretch with skin movement, avoiding powder caking and peeling caused by facial expressions.

[0035] Carbomer and tromethamine are added to the aqueous phase to thicken it. Butylene glycol, 1,2-pentanediol and glycerin are added to improve the moisturizing properties, skin smoothness and formula stability of the aqueous phase, while also working synergistically to enhance the preservative effect and improve the antibacterial ability of the system while reducing the addition of traditional preservatives.

[0036] Component 3, hydrophobic titanium dioxide / zinc oxide, and component 4, silylated silica, are used in combination. Due to the principle of ultrafine hydrophobic powder, the synergistic effect between the ultrafine hydrophobic powders—the combination of titanium dioxide, zinc oxide, and silylated silica—achieves a "1+1+1>3" effect based on the ultrafine particle size effect and hydrophobic modification. On the one hand, the porous structure of silylated silica provides dispersion space for titanium dioxide and zinc oxide, preventing agglomeration due to direct contact; on the other hand, the consistent hydrophobicity of the three powders reduces the interfacial energy difference, allowing them to form a uniform hydrophobic region in the system, enhancing the adsorption and shielding capabilities against ultraviolet rays, pollutants, etc.

[0037] The ultra-fine powder and hydrogel work together to achieve "lightweight and high coverage" (only one layer is needed to cover acne marks). The triple action of silica absorbing oil, hydrophobic powder resisting fusion, and film-forming agent locking in makeup keeps the makeup fresh and oil-free, and extends the makeup time compared to systems without film-forming agents.

[0038] The hydrogel balances the dryness of the powder, while the film-forming agent enhances its flexibility, ensuring a smooth and non-caking application and a comfortable, non-tight feel during makeup wear. The powder form is portable, eliminating concerns about leakage, making it suitable for commuting, travel, and other occasions.

[0039] The beneficial effects of the above scheme are as follows: This invention utilizes ultrafine hydrophobic titanium dioxide / zinc oxide / silylated silica powder, stirred together with a thickening hydrogel, to construct a stable system that disperses the powder in a liquid. The core improvement of this invention lies in the synergistic combination of ultrafine hydrophobic titanium dioxide / zinc oxide / silylated silica powder, a thickening hydrogel, and an acrylic (ester) / ethylhexyl acrylate crosslinking polymer film-forming agent. Through a stirring process, a powder-based foundation system with stable dispersion, morphology transformation, and strong film-forming properties is constructed. This improvement not only overcomes the technical bottlenecks of traditional powder dispersions, such as easy agglomeration and poor stability, but also solves the problem of film layer damage and makeup effect collapse in the later stages of makeup wear by introducing a film-forming agent. It provides a more complete technical solution for foundation products that combine "base application" and "setting" functions.

[0040] 1. Synergistic effect between ultrafine hydrophobic powders: The combination of titanium dioxide and zinc oxide achieves the superimposed effect of "full-band sun protection + high concealing". The introduction of silyl alkyl silica further amplifies the advantages - its porous structure adsorbs oil while providing dispersion space for the former two, avoiding uneven makeup effect caused by agglomeration. The three work together to form a triple barrier of "protection-concealing-oil control" on the skin surface, which improves the effect by more than 40% compared with a single powder component (verified by in vitro oil control experiments).

[0041] 2. Synergistic effect of powder and thickening hydrogel: The "humidity responsiveness" of the hydrogel solves the pain points of using powder products - it is stable when dry and quickly transforms into a liquid texture after contact with the skin, avoiding the problems of traditional loose powder falling and liquid foundation running; at the same time, the viscosity of the hydrogel and the hydrophobicity of the powder form a "dynamic balance", which not only ensures the smoothness when applying, but also locks the powder after film formation to resist the erosion of sweat and oil, extending the makeup time to more than 8 hours (50% longer than conventional foundation).

[0042] 3. Synergistic effect of film-forming agent and other components: Acrylic (ester) / ethylhexyl acrylate cross-linked polymer and thickening hydrogel form "dual network support" - the three-dimensional network of hydrogel is responsible for the initial powder dispersion and morphology transformation, while the film-forming agent builds a more stable continuous film layer on this basis, increasing the powder encapsulation rate to more than 95% and reducing makeup removal caused by powder detachment; when synergistic with hydrophobic powder, the oil resistance of the film-forming agent and the oil repellency of the powder form "dual protection", increasing the ability to resist skin oil penetration by 60%, and the film layer can still maintain integrity even in high temperature environments; in addition, the flexibility of the film-forming agent can alleviate the tightness that ultrafine powder may cause, and combined with the moisturizing properties of hydrogel, it can keep the makeup adherent during the makeup process without dryness and cracking.

[0043] Complementary functions and scenario adaptation: For quick morning makeup, the four components work together to achieve "one-step" results—titanium dioxide and zinc oxide provide instant concealing and sun protection, silylated silica absorbs oil to prevent makeup from fading, hydrogel ensures rapid powder application, and film-forming agent locks in the makeup effect, eliminating the need for repeated touch-ups; for oily skin users, the hydrophobicity of the powder, the oil-absorbing properties of silica, and the oil resistance of the film-forming agent form a triple oil-control system, reducing the frequency of touch-ups to once a day; while dry skin users can avoid caking and tightness through the moisturizing properties of the hydrogel and the flexibility of the film-forming agent, achieving "suitability for all skin types".

[0044] This powder foundation, developed using this technology, is a two-in-one product combining loose powder and foundation. It integrates the base makeup and setting steps into one, allowing users to complete their base makeup with a simple pressing and application motion, significantly simplifying the makeup process and perfectly meeting the needs of efficient makeup application. Meanwhile, the poor oil control performance of traditional foundation products has long been a pain point for consumers. Many liquid foundations have an oily texture, causing the skin to quickly become shiny, especially in hot weather or in the T-zone where oil secretion is high. This leads to makeup fading and patchiness within a short time, severely affecting the longevity of the makeup. Even when used with loose powder, the oil control effect of some products is insufficient, requiring frequent touch-ups. This powder foundation, after setting, forms a stable protective film that effectively absorbs excess oil from the skin, fundamentally solving the problem of traditional foundation products' lack of oil control. This allows the makeup to remain fresh and clean for a long time, further enhancing the product's practicality and competitiveness in everyday makeup scenarios.

[0045] In terms of concealing power, conventional liquid foundations vary in their performance. For deeper acne scars, blemishes, and other imperfections, multiple layers are often required to achieve a good coverage effect, but this can easily lead to a heavy makeup look and make the skin appear unnatural. The powder foundation of this application, after transforming into a liquid form, can closely adhere to the skin texture and has excellent coverage for various imperfections. A single layer is sufficient to effectively cover most imperfections, achieving a lightweight yet highly concealing makeup effect.

[0046] Long-lasting makeup is also crucial. Regular liquid foundations tend to smudge and become patchy over time due to factors like sebum production and sweating, especially in oily areas like the T-zone, where the makeup's effectiveness often diminishes after just a few hours. This product, however, has a strong powdery feel and forms a protective film on the skin after application, effectively resisting oil and sweat, maintaining the integrity and longevity of the makeup, keeping it clean and fresh all day long.

[0047] In terms of makeup finish, even if regular liquid foundation is advertised as lightweight, it can still feel somewhat oily in actual use, especially for people with oily skin, which can increase the burden on the skin and make it look greasy. This powder foundation, when transformed into a liquid form, presents a natural powdery finish that is refreshing and non-greasy, making the skin look more delicate, soft, and sophisticated.

[0048] When stored in powder form, it is less affected by temperature and humidity (no separation after 3 months of storage at 40℃), solving the problem of liquid foundation deterioration in summer; when used, it transforms through hydrogel to adapt to different skin conditions (dry / oily / combination skin).

[0049] In one optimized embodiment, S2 includes: S2-A: Add deionized water and glycerin to container one, and start stirring at 500-800 rpm to form a vortex in the water. First, sprinkle carbomer 940 powder at the first rate until it reaches 1 / 3 of the total formula weight of carbomer 940 powder, and then sprinkle carbomer 940 powder at the second rate until it reaches the total formula weight of carbomer 940 powder. After the powder is applied, increase the speed to 1500-2000 rpm and continue stirring until the powder is completely dispersed; S2-B: After dispersing S2-A, continue stirring at 500-800 rpm for a preset swelling time, then test the material viscosity. If the viscosity stability requirement is not met within the swelling time, extend the swelling time by 5-10 minutes until the viscosity meets the viscosity stability requirement. When the viscosity stability requirement is met, construct a time-viscosity curve, and determine the actual platform viscosity and effective viscosity change rate based on the time-viscosity curve. An alarm will be triggered if the actual platform viscosity does not meet the required range. S2-C: When S2-B does not alarm, after the viscosity stability requirement is met, the theoretical addition rate of tromethamine solution is determined based on the effective viscosity change rate. Tromethamine solution is added at the theoretical addition rate of tromethamine solution, and the mixture is stirred while adding until the system forms a hydrogel. S2-D: After the hydrogel is formed, continue stirring at 300-500 rpm for 10-15 min.

[0050] The total formulation weight of Carbomer 940 powder is G, with a first rate of 0.08 G / min to 0.12 G / min and a second rate of 0.3 G / min to 0.35 G / min.

[0051] The total weight of the carbomer 940 powder formulation is: the total amount of carbomer (carbomer 940 powder) added in a single production of powder foundation, corresponding to the complete formulation of this powder foundation production.

[0052] S2-A: The first 1 / 3 of the powder is slowly added to ensure it is fully wetted and settles, preventing it from floating or agglomerating, and creating a uniform initial dispersion environment. The last 2 / 3 of the powder is quickly added to the already wetted system, balancing dispersion quality and production efficiency, and avoiding prolonged exposure that could cause the powder to absorb water and become ineffective.

[0053] S2-B: The preset swelling time is: under the baseline conditions (corresponding to the baseline ambient temperature, such as 25℃), deionized water is selected, and the specific batch of glycerol and carbomer 940 powder raw materials are used. After completing S2-A, continue stirring at 500-800 rpm until the carbomer 940 powder is completely swollen (reaching the viscosity stability requirement). Viscosity stability requirement: viscosity fluctuation range ≤ ±3% within 3 to 5 minutes; the viscosity fluctuation range refers to the percentage change rate of the difference between the measured maximum and minimum viscosity of the system relative to the average viscosity within the judgment period. The preset swelling time is set to 0.8 to 0.85 times the preset swelling time. In the time-viscosity curve, the horizontal axis represents the swelling time of a single production run, and the vertical axis represents the viscosity test value of the swollen system corresponding to the horizontal axis. The end point of the horizontal axis corresponds to the moment when the viscosity stability requirement is met. The starting point of the horizontal axis of the curve is the swelling time of a single production run after stirring for a preset multiple of the preset swelling time, and the first time the viscosity of the material is tested. Platform viscosity is the average viscosity during a period of continuous 3-5 minutes when the viscosity fluctuation range is ≤ ±3%. The effective viscosity change rate is: (viscosity detection value at the initial moment of the period when the viscosity fluctuation range is ≤ ±3% within 3 to 5 minutes - viscosity detection value at the starting point of the curve) ÷ |swelling time of a single production at the initial moment of the period when the viscosity fluctuation range is ≤ ±3% within 3 to 5 minutes - swelling time of a single production at the starting point of the curve|. S2-C: The initial verification addition rate of tromethamine solution was determined based on the effective viscosity change rate, specifically as follows: First, obtain the baseline effective viscosity change rate and the baseline addition rate of tromethamine solution (typically 0.45H / min): Under baseline conditions (corresponding to baseline ambient temperature), deionized water is selected, and specific batches of glycerol and carbomer 940 powder raw materials are used for verification. After completing S2-A and S2-B (and determining the actual effective viscosity change rate in S2-B, i.e., the baseline effective viscosity change rate), tromethamine solution is continuously added to the fully swollen carbomer system at a gradient addition rate (0.1H / min, 0.15H / min, 0.2H / min, 0.25H / min, 0.3H / min, 0.35H / min, 0.4H / min, 0.45H / min, 0.5H / min, 0.55H / min... covering the commonly used production range), and it is determined whether the addition is qualified; the total amount of tromethamine solution produced in a single batch is H; The criteria for determining the qualified rate are: no powder agglomeration, no fish-eye lumps, no sudden increase in viscosity (viscosity increase within a single minute does not exceed 15%), a steady increase in pH (pH increase does not exceed 0.5 within any 1 minute), and the final hydrogel is uniform and free of lumps. For each set of gradient dispensing rates, verify whether they meet the above qualification criteria one by one, and select the highest dispensing rate that meets all the judgment criteria as the benchmark effective viscosity change rate.

[0054] The initial rate adjustment strategy is as follows: The viscosity deviation rate satisfies [-0.1, 0.1], and the theoretical addition rate of tromethamine solution = "the baseline addition rate of tromethamine solution"; If the viscosity deviation rate is greater than 0.1, the theoretical addition rate of tromethamine solution = the baseline addition rate of tromethamine solution - 0.03 H / min; The viscosity deviation rate is less than -0.1, and the theoretical addition rate of tromethamine solution = the baseline addition rate of tromethamine solution + 0.03 H / min; The viscosity deviation rate is: (actual effective viscosity change rate - reference effective viscosity change rate) ÷ reference effective viscosity change rate; Platform viscosity requirements: To meet the gelling performance and production stability requirements of this powder foundation formulation system, the platform viscosity must meet the stability requirement of viscosity fluctuation within ≤±3% over a continuous 3-5 minutes. Furthermore, the overall viscosity of the system must be adapted to the characteristics of the formulation components and process requirements, ensuring that carbomer fully swells and gels, and that the powder is uniformly dispersed without sedimentation, while avoiding excessively high viscosity leading to a heavy, sticky application, or excessively low viscosity causing powder scattering and insufficient makeup holding power. Specific viscosity thresholds need to be determined comprehensively through process validation and product performance testing based on parameters such as the type and amount of carbomer added, the type of film-forming agent, the powder solid content, and the ratio of moisturizers in the formulation, to achieve the optimal balance between gelling properties, stability, and user experience. Typical platform viscosity ranges are as follows: for lightweight, long-lasting makeup formulations, 8000-15000 mPa·s is preferred; for standard concealer formulations, 15000-22000 mPa·s is preferred. Platform viscosity was measured at 25℃, using a #6 rotor, and at 20 rpm. The beneficial effects of the above scheme are as follows: 1. S2-A: Through a graded feeding strategy of "feeding the first 1 / 3 of the powder at low speed and the last 2 / 3 at high speed", the powder is first fed at low speed to fully wet and settle, creating a uniform initial dispersion environment and avoiding powder floating and agglomeration to form an "outer shell" that hinders internal swelling; then the remaining powder is fed at high speed, taking into account both dispersion quality and production efficiency, solving the industry pain points of carbomer powder being prone to agglomeration and insufficient swelling in traditional processes.

[0055] By controlling the initial rotation speed of 500-800 rpm to form a stable vortex, the powder is precisely added along the edge of the vortex, avoiding direct impact and splashing of the powder on the liquid surface and adhesion to the container wall. This ensures that each batch of powder can fully contact the water, providing a uniform initial system for subsequent swelling and gelation, and significantly improving the process stability between batches.

[0056] The high-speed dispersion step of 1500-2000 rpm can quickly complete the dispersion of the powder, avoid prolonged exposure which can cause the powder to absorb water and become ineffective, and at the same time reduce the waste of raw materials caused by agglomeration, thus maximizing the carbomer thickening efficiency.

[0057] 2. Through closed-loop management of “preset swelling time, viscosity stability detection, and time-viscosity curve construction”, the traditional “experience-based judgment of swelling completion” is upgraded to a quantifiable and reproducible standard judgment. The core indicator of swelling completion is “viscosity fluctuation within 3-5 minutes ≤ ±3%”, which avoids thickening failure due to insufficient swelling or abnormal system viscosity due to excessive swelling.

[0058] To address fluctuations in swelling rate caused by variations in ambient temperature and raw material batches, an adaptive adjustment mechanism is set up to extend the swelling time by 5-10 minutes if it is insufficient. At the same time, the actual platform viscosity and effective viscosity change rate are accurately calculated through time-viscosity curves, allowing the process to automatically adapt to different production conditions without the need for frequent manual parameter adjustments.

[0059] By comparing the platform viscosity with the required range, an automatic alarm is triggered when the actual platform viscosity does not meet the requirements, thus intercepting unqualified systems with abnormal swelling in advance.

[0060] 3. The effective viscosity change rate obtained through the time-viscosity curve provides the core basis for the precise addition rate of tromethamine, realizing the process linkage between the swelling process and the gelation process, and ensuring reliable addition.

[0061] The theoretical addition rate of tromethamine is determined based on the effective viscosity change rate. Combined with a dynamic adjustment strategy using viscosity deviation rate, the neutralization and gelation process is made controllable. This avoids both the sudden increase in local pH, powder agglomeration, fish-eye agglomeration, and viscosity surge caused by excessively rapid addition, and uneven gelation and poor system stability caused by excessively slow addition. Precise fine-tuning of the addition rate using viscosity deviation rate (the ratio of the actual effective viscosity change rate to the reference rate) allows the addition rate to adapt to carbomer systems in different swelling states. Regardless of whether the swelling rate is too fast or too slow, a suitable addition rate is matched, ensuring consistent gelation performance.

[0062] 4. After gelation, stir at a low speed of 300-500 rpm for 10-15 minutes to eliminate local internal stress generated during neutralization, making the three-dimensional network structure of the hydrogel more uniform and dense. At the same time, it removes residual micro air bubbles in the system, avoiding air bubbles and pores after subsequent powder mixing, thus improving the appearance and application texture of the foundation.

[0063] In an optimized embodiment, based on Example 1, after the hydrogel is formed in S2, the stirring speed is reduced while stirring continues, and the conductivity is periodically detected (to determine the end of the conductivity stabilization period described below), a time-conductivity sequence is constructed, and the conductivity stabilization period and actual conductivity stabilization rate are determined based on the time-conductivity sequence; S3 includes: S3-A: Add butanediol and 1,2-pentanediol to container two, heat to 60℃-70℃, stir at 400-500 rpm for 3 min to premix, add p-hydroxyacetophenone, stir at 400-500 rpm at 60℃-70℃ until completely dissolved, and keep warm for 8-10 min to obtain the solution. S3-B: Cool the solution obtained in S3-A to an absolute temperature difference of less than or equal to 2°C with the hydrogel obtained in S2. Determine the theoretical feeding rate of the material obtained in S3-A based on the actual conductivity stabilization rate. Then, control the rotation speed of container two to 400-500 rpm and add the solution obtained in S3-A to the hydrogel obtained in S2 at the theoretical feeding rate. After all the solution is added, stir at 600-800 r / min for 10-15 min.

[0064] The time-conductivity sequence is, for example, [(t1,κ1), (t2,κ2), (t3,κ3), ..., (tn,κn)]; t1, t2, t3, and tn are the times of the 1st, 2nd, 3rd, and nth conductivity measurements, respectively; k1, k2, k3, and kn are the conductivity values ​​obtained from the 1st, 2nd, 3rd, and nth conductivity measurements, respectively. Stable conductivity period (number of tests not less than 5): including the conductivity of the last test, the period of continuous testing and conductivity fluctuation range ≤ ±5%; the conductivity fluctuation range refers to the percentage change rate of the difference between the measured maximum and minimum conductivity of the system relative to the average conductivity within the judgment period. The actual conductivity stabilization rate is the conductivity stabilization rate determined based on the current time-conductivity sequence: The conductivity stabilization rate = (maximum conductivity during the conductivity stabilization period - minimum conductivity during the conductivity stabilization period) ÷ |Detection time corresponding to the maximum conductivity during the conductivity stabilization period - Detection time corresponding to the minimum conductivity during the conductivity stabilization period|; The conductivity stabilization rate directly reflects the dynamic change trend of the hydrogel system in the stabilization stage. The smaller the rate value, the more stable the hydrogel structure and the higher its tolerance to external mixing shocks, corresponding to a faster theoretical feeding rate. Conversely, the larger the rate value, the lower the tolerance of the hydrogel system, corresponding to a slower theoretical feeding rate.

[0065] The total weight of the solution obtained from a single production of S3-A is denoted as M; When the conductivity stabilizes at a rate ≤ 0.05 mS / (cm·s): the system experiences normal small fluctuations and remains stable, with a theoretical feeding rate of 0.12 M / min - 0.15 M / min; When 0.05 mS / (cm·s) < conductivity stability rate ≤ 0.12 mS / (cm·s): the system fluctuates greatly and there are still minor structural adjustments. The theoretical feeding rate is 0.08 M / min - 0.1 M / min.

[0066] An early warning is issued when the conductivity stabilization rate is >0.12 mS / (cm·s), feeding is paused, and the hydrogel system is prompted to be retested to determine the cause of the abnormality and make adjustments. The beneficial effects of this plan are: 1. First, premix the polyols (butanediol and 1,2-pentanediol) to form a homogeneous solvent system by utilizing the miscibility of the polyols. Then, add p-hydroxyacetophenone to avoid the problem of excessively high local concentration of p-hydroxyacetophenone and insufficient dissolution when directly mixed. The heat preservation process allows the dissolution system to reach thermodynamic equilibrium, ensuring the homogeneity of the S3-A solution. 2. This solution achieves precise differentiated feeding control based on a stable conductivity rate: When the system is stable (rate ≤ 0.05 mS / (cm·s)), a rapid feeding rate of 0.12 M / min-0.15 M / min is adopted to significantly shorten the production cycle while ensuring system stability. When the system fluctuation is large (0.05mS / (cm·s) < rate ≤ 0.12mS / (cm·s)), use a slow feeding rate of 0.08M / min-0.1M / min to avoid impacting and damaging the gel structure and to ensure uniform dispersion of the raw materials; The proportional feeding method, based on the total weight M, is perfectly adapted to different production scales (small-scale / pilot-scale / mass production) without the need to readjust parameters, and has extremely strong process scalability.

[0067] The combination of low-speed stirring and differentiated feeding rates ensures that the solution is smoothly incorporated into the hydrogel, avoiding local instability of the gel caused by excessively high local concentrations and ensuring the homogeneity of the entire system. The solution requires an absolute temperature difference of ≤2℃ between the S3-A solution and the hydrogel, avoiding thermal shock from the high-temperature solution to the low-temperature hydrogel, preventing the gel structure from collapsing and demulsifying, ensuring the uniformity and stability of the foundation system, and ultimately significantly improving the product's spreadability, adherence, and staying power.

[0068] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a powder foundation, characterized in that: Includes the following steps: S1: The filler, titanium dioxide colorant, inorganic colorant, adsorbent, and film-forming agent are placed in a pulverizing device for crushing and mixing, and then sieved to obtain a powder phase; S2: Add deionized water and glycerin to container one, start stirring at 500-800 rpm to form a vortex in the water, and while maintaining the speed, sprinkle carbomer 940 powder into the edge of the vortex. After sprinkling the powder, increase the speed to 1500-2000 rpm and continue stirring until the powder is completely dispersed. After dispersion, continue stirring at 500-800 rpm. After swelling, add tromethorphan solution while stirring until the system forms a hydrogel. After the hydrogel is formed, reduce the speed and continue stirring. S3: Add butanediol, 1,2-pentanediol, and p-hydroxyacetophenone to container two and dissolve them at 60-70℃ to obtain a solution. Add the solution to the hydrogel obtained in S2 and stir to mix. S4: Add the powder obtained in S1 to the material obtained in S3, stir at 700-800 rpm, discharge after the first stirring time, and pass through a 20-mesh sieve; then pour the material that has passed through the 20-mesh sieve into container two, stir at 700-800 rpm for a second stirring time, discharge after the second stirring time, and pass through a 40-mesh sieve; the first and second stirring times are both 3 minutes. The adsorbent is silylated silica, and the film-forming agent is an acrylate / ethylhexyl acrylate crosslinked polymer; The tromethamine solution is a 10% (w / w) aqueous solution of tromethamine. The filler components include: mica, polydimethylsiloxane, and triethoxyoctylsilane; The components of titanium dioxide colorants are: titanium dioxide, aluminum hydroxide, and triethoxyoctylsilane; Titanium dioxide is surface-treated with aluminum hydroxide and triethoxyoctylsilane to obtain the titanium dioxide-based colorant; Inorganic colorants include titanium dioxide and zinc oxide; titanium dioxide and zinc oxide are surface-treated with surface treatment agents to obtain inorganic colorants; surface treatment agents include: aluminum hydroxide, stearic acid, and polydimethylsiloxane alcohol; The titanium dioxide is ultrafine hydrophobic titanium dioxide, and the zinc oxide is ultrafine hydrophobic zinc oxide; S2 includes: S2-A: Add deionized water and glycerin to container one, and start stirring at 500-800 rpm to form a vortex in the water. First, sprinkle carbomer 940 powder at the first rate until it reaches 1 / 3 of the total formula weight of carbomer 940 powder, and then sprinkle carbomer 940 powder at the second rate until it reaches the total formula weight of carbomer 940 powder. After the powder is applied, increase the speed to 1500-2000 rpm and continue stirring until the powder is completely dispersed; S2-B: After dispersing S2-A, continue stirring at 500-800 rpm for a preset swelling time, then test the material viscosity. If the viscosity stability requirement is not met within the swelling time, extend the swelling time by 5-10 minutes until the viscosity meets the viscosity stability requirement. When the viscosity stability requirement is met, construct a time-viscosity curve, and determine the actual plateau viscosity and effective viscosity change rate based on the time-viscosity curve. The preset multiple is 0.8 to 0.85 times. Viscosity stability requirement: viscosity fluctuation range ≤ ±3% within 3 to 5 minutes. The viscosity fluctuation range refers to the percentage change rate of the difference between the measured maximum and minimum viscosity values ​​of the system relative to the average viscosity within the judgment time period. Platform viscosity is the average viscosity during a period of continuous 3-5 minutes when the viscosity fluctuation range is ≤ ±3%. The total formulation weight of Carbomer 940 powder is G, with a first rate of 0.08 G / min to 0.12 G / min and a second rate of 0.3 G / min to 0.35 G / min; An alarm will be triggered if the actual platform viscosity does not meet the required range. S2-C: When S2-B does not alarm, after the viscosity stability requirement is met, the theoretical addition rate of tromethamine solution is determined based on the effective viscosity change rate. Tromethamine solution is added at the theoretical addition rate of tromethamine solution, and the mixture is stirred while adding until the system forms a hydrogel. S2-D: After the hydrogel is formed, continue stirring at 300-500 rpm for 10-15 min; The raw material composition of powder foundation includes the following percentages by weight: filler 5-10%, titanium dioxide colorant 5-10%, inorganic colorant 1-5%, adsorbent 0.5-3%, film-forming agent 5-10%, deionized water 40-70%, butylene glycol 1-5%, 1,2-pentanediol 1-5%, glycerin 1-5%, p-hydroxyacetophenone 0.1-0.5%, carbomer 940 powder 0.05-0.3%, and tromethamine 0.02-0.1%.

2. The method for preparing a powder foundation according to claim 1, characterized in that: In S1: the rotation speed is 2900 rpm, and the screen is a 150 mesh screen.

3. A powder foundation, characterized in that: It is prepared using the powder foundation preparation method described in any one of claims 1-2.

Images