Hydrophobic surface treatment process of powder and application of hydrophobic surface treatment process in cosmetics

Abstract

The invention relates to the technical field of cosmetics, in particular to a hydrophobization surface treatment process of powder and application of the hydrophobization surface treatment process in cosmetics. Comprising the following steps: uniformly mixing powder with an organic solvent to obtain a primary dispersion; dispersing the primary dispersion under the pressure of more than 100 bar to obtain a secondary dispersion; and carrying out surface treatment on the secondary dispersion by using a surface treating agent, removing the solvent, carrying out heat treatment, and crushing to obtain treated powder. When the surface treating agent is used for treating the powder, dispersion is carried out twice and dispersion is carried out under the pressure of more than 100bar for the second time, so that the high-hydrophobicity powder can be obtained, secondary / tertiary particles are inhibited to the greatest extent, and the skin feeling is improved; meanwhile, when the treated powder is applied to foundation make-up, excellent skin feeling, concealing force and stability can be achieved.

Description

A hydrophobic surface treatment process for powders and its application in cosmetics Technical Field

[0001] This invention relates to the field of cosmetic technology, specifically to a hydrophobic surface treatment process for powders and its application in cosmetics. Background Technology

[0002] In color cosmetics such as foundation and sunscreen products, powders must meet multiple core requirements: color cosmetics must be sweat- and water-resistant to prevent makeup from fading; oil-in-water or silicone-in-water liquid foundations also require the powder to be free of fine agglomerates, easy to apply, and have excellent oil-phase dispersibility to ensure concealing effect and color presentation; in sunscreen products, the oil-phase dispersibility of particulate titanium dioxide and zinc oxide directly affects sun protection performance, therefore, hydrophobic treated powders have become key application materials. Existing methods for preparing hydrophobic treated powders mainly include: mixing mineral powders or inorganic oxide powders with hydrogen-containing silicon compounds, applying a single layer, and then heat-treating to impart hydrophobicity; dissolving polydimethylsiloxane or polymethylhydrosiloxane in an organic solvent, contacting and adhering it to the powder, adding a catalyst if necessary, and then heat-treating; coating with aminosilane and polydimethylsiloxane alcohol respectively, followed by heat treatment.

[0003] However, there are significant drawbacks: when using polymethylhydrosiloxane for treatment, hydrogen gas is generated if water or alcohol is present, and different powders have significantly different reactivity to silicon-based treatment agents, making it difficult to achieve sufficient hydrophobicity in some scenarios; the method disclosed in Japanese patent application JP2018062562A, which uses sodium hydroxide as a coating catalyst and alkylsilane for treatment, although it improves the hydrophobic effect, fails to achieve the required fine texture when applied to pressed powder or liquid foundation because the powder is not sufficiently uniformly dispersed before surface treatment; at the same time, secondary and tertiary particles remaining during surface treatment limit the skin feel; if subsequent redispersing is carried out by ball milling, bead milling, or air jet milling, some agglomerated powders may break apart, exposing untreated surfaces, resulting in the dispersion not maintaining a uniform state for a long time, insufficient dispersion stability, and further affecting the product user experience. Summary of the Invention

[0004] The first aspect of the present invention provides a hydrophobic surface treatment process for powder, comprising the following steps: mixing the powder with an organic solvent to obtain a primary dispersion; dispersing the primary dispersion under a pressure greater than 100 bar to obtain a secondary dispersion; surface treating the secondary dispersion with a surface treatment agent, followed by solvent removal, heat treatment, and pulverization to obtain the treated powder.

[0005] This invention achieves multiple technical effects through a process design involving two dispersion stages and a high-pressure secondary dispersion: the first dispersion stage mixes the powder with the organic solvent uniformly, initially breaking down the original agglomerates of the powder and creating a uniform system environment for subsequent high-pressure dispersion and the action of surface treatment agents; the second dispersion stage, under high pressure conditions greater than 100 bar, uses a homogenizer to powerfully break down the residual fine agglomerates in the powder through high-pressure shearing, impact, and other mechanical actions, bringing the powder to a monodisperse or near-monodisperse state. This not only suppresses the formation and residue of secondary / tertiary particles to the maximum extent from the source, but also fully exposes the specific surface area of ​​the powder particles. This highly dispersed state ensures that the surface treatment agent can uniformly and completely cover the surface of each powder particle, forming a continuous and dense hydrophobic coating layer through adsorption or chemical bonding. This avoids the problem of insufficient hydrophobicity caused by the inability of the powder's internal surface to effectively contact the treatment agent due to agglomeration, thus obtaining a highly hydrophobic powder. At the same time, the fine and uniform powder particles formed after high-pressure dispersion can reduce the friction between particles during application, reduce the roughness when in contact with the skin, and improve the smoothness and adhesion of the application. Combined with the hydrophobic coating layer, it reduces the skin feel defects caused by particle agglomeration, ultimately achieving excellent skin feel.

[0006] The average particle size of the powder is <1 μm.

[0007] Optionally, the average particle size of the powder is 0.01-0.31 μm.

[0008] The heat treatment temperature is 80-160℃.

[0009] The solvent removal can be performed using a plate and frame filter press, centrifuge, distiller, vacuum dryer, or hot air dryer.

[0010] The pulverization process can utilize conventional powder pulverization equipment such as hammer mills, needle mills, and air jet mills to pulverize powders that have been dried after heat treatment.

[0011] The powder includes at least one of organic pigments and inorganic pigments.

[0012] The inorganic pigments include at least one of inorganic metal compounds and silicate compounds.

[0013] The organic pigment includes at least one of the following color numbers: Red 201, Red 202, Red 204, Red 205, Red 220, Red 226, Red 228, Red 305, Orange 203, Orange 204, Yellow 205, Yellow 401, Blue 404, Red 3, Red 104, Red 106, Red 227, Red 230, Red 401, Red 505, Orange 205, Yellow 4, Yellow 5, Yellow 220, Yellow 203, Green 3, and Blue 1; optionally, the organic pigment includes zirconium lake, barium lake, or aluminum lake of the above color numbers.

[0014] The inorganic metal compound pigments include at least one of the following: ultramarine, dark blue, manganese violet, titanium dioxide-coated mica, bismuth oxychloride, etc.; metal oxides and hydroxides: magnesium oxide, potassium oxide, potassium hydroxide, aluminum oxide, aluminum hydroxide, silicon dioxide, red iron oxide, yellow iron oxide, black iron oxide, iron hydroxide, titanium dioxide, low titanium oxide, zirconium oxide, chromium oxide, manganese oxide, cobalt oxide, nickel oxide.

[0015] The silicate compounds include at least one of mica, silica, and talc.

[0016] The mica includes at least one of muscovite, phlogopite, biotite, sericite, and synthetic mica.

[0017] Optionally, the synthetic mica comprises KAl2(AlSi3)O 10 F2, KMg3(AlSi3)O 10 F2, K(MgFe3)(AlSi3)O 10 At least one of F2.

[0018] The pearlescent pigments include mica-titanium composite materials (where the titanium component can be any one of titanium dioxide, low-oxide titanium, or titanium oxynitride), mica-iron oxide composite materials, low-oxide titanium, and titanium oxynitride. Mica-titanium or iron oxide composite materials can also be mixed with one or more of bismuth oxychloride, iron oxide, azurite, chromium oxide, carbon black, carmine, or ultramarine.

[0019] The silicate compounds include phyllosilicate minerals (any one of the kaolinite group, montmorillonite group, clay mica group, chlorite group, and serpentine group) and framework silicate minerals.

[0020] Optionally, the silicate compound includes at least one of pyrophyllite, talc, chlorite, kaolinite, halloysite, montmorillonite, chlorite, soapstone, zinc soapstone, and bentonite.

[0021] Optionally, the powder includes porous powder, which includes at least one of the following porous substances: glass beads, silica, zeolite, metal oxide, metal nitride, silicate mineral, carbonate mineral, sulfate mineral, phosphate mineral, cellulose, and synthetic resin.

[0022] Optionally, the pressure is ≥200 bar.

[0023] Optionally, the pressure is 200-1000 bar.

[0024] The primary dispersion includes dispersion obtained using the following machines: dispersion mixer, rotor-stator mixer, high-speed homogenizer.

[0025] The secondary dispersion was obtained by homogenization.

[0026] Optionally, the homogenizer may be a dynamic valve pressure regulating type or a cavity type with a fixed nozzle orifice.

[0027] Optionally, the dynamic valve pressure regulating type includes SPXFLOW's APV.

[0028] Optionally, the cavity type of the fixed nozzle orifice includes Microfluidics' Microfludizer.

[0029] The weight ratio of the powder to the solvent is 1:(0.2-5).

[0030] Optionally, the weight ratio of the powder to the solvent is 1:(0.6-2).

[0031] The secondary dispersion is dispersed 1-3 times by a homogenizer.

[0032] The amount of the surface treatment agent is 0.1-20 wt% of the secondary dispersion.

[0033] The surface treatment agent includes at least one of the following types: siloxanes, amino acids, fatty acids, phospholipids, esters, and titanium compounds.

[0034] The siloxanes include at least one of the following: hydrogenated polydimethylsiloxane, triethoxyoctylsilane, polymethylsilane, polydimethylsiloxane alcohol, polydimethylsiloxane alcohol stearate, triethoxysilyl ethyl polydimethylsiloxane ethylhexyl polydimethylsiloxane, acrylate / polydimethylsiloxane copolymer, triethoxysilyl, cetyl PEG / PPG-10 / 1 polydimethylsiloxane.

[0035] The amino acids include at least one of the following: lauroyl lysine, disodium stearoyl glutamate, sodium lauroyl glutamate, and sodium cocoyl glutamate.

[0036] The fatty acids include at least one of the following: metal soaps, fatty acids, fatty acid derivatives, and fatty acid amides.

[0037] The metal soaps include at least one of the following: zinc stearate, magnesium stearate, calcium stearate, aluminum stearate, aluminum myristate, zinc myristate, and magnesium myristate.

[0038] The fatty acids include at least one of the following: stearic acid, palmitic acid, lauric acid, oleic acid, and myristic acid.

[0039] The fatty acid derivatives include at least one of the following: isopropyl myristate, isopropyl palmitate, and glyceryl stearate.

[0040] The fatty acid amide includes at least one of the following: stearamide and oleamide.

[0041] Optionally, the surface treatment agent contains 10-30 wt% of a silane compound.

[0042] Optionally, the silane compound includes at least one of the following: triethoxysilane, methyldiethoxysilane, dimethylethoxysilane, vinyltriethoxysilane, vinyldimethylethoxysilane, methylvinyldiethoxysilane, vinyldiphenylethoxysilane, allyldimethylethoxysilane, 3-glycidoxypropyltriethyloxysilane, 5,6-epoxyhexyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloyloxypropyltriethyloxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltriethoxysilane, and 3-mercaptopropylmethyldiethoxysilane.

[0043] Optionally, the surface treatment agent includes at least one of triethoxyoctylsilane, polydimethylsiloxane, aminopropylsilane, and dihydrosiloxane.

[0044] The surface treatment methods include wet processing.

[0045] A second aspect of the present invention provides a cosmetic product comprising the treated powder.

[0046] Optionally, the cosmetic product is a foundation.

[0047] Beneficial effects 1. When the powder is treated with a surface treatment agent, the present invention performs two dispersions, with the second dispersion performed at a pressure greater than 100 bar, which can obtain highly hydrophobic powder, while maximally suppressing the generation of secondary / tertiary particles and improving skin feel.

[0048] 2. The present invention limits the average particle size of the powder before treatment to <1μm, which can meet the dispersion requirements in the cosmetics field.

[0049] 3. The present invention specifies that the second dispersion is carried out under a pressure of ≥200 bar, which can further improve the physical stability of the processed powder.

[0050] 4. When the powder processed by this invention is applied to foundation, it can achieve excellent skin feel, coverage and stability.

[0051] 5. The invention provides a simple powder processing technology that can be mass-produced. Attached Figure Description

[0052] Figure 1 shows the stability test images of Examples 1-3 and Comparative Examples 1-2 in the first week, from left to right corresponding to Comparative Example 2, Comparative Example 1, Example 3, Example 2, and Example 1.

[0053] Figure 2 shows the stability test images of Examples 1-3 and Comparative Examples 1-2 in the second week, from left to right corresponding to Comparative Example 2, Comparative Example 1, Example 3, Example 2, and Example 1.

[0054] Figure 3 shows the stability test images of Examples 1-3 and Comparative Examples 1-2 in week 4, from left to right corresponding to Comparative Example 2, Comparative Example 1, Example 3, Example 2, and Example 1.

[0055] Figure 4 shows the stability test images of Examples 1-3 and Comparative Examples 1-2 in week 8, where from left to right they correspond to Comparative Example 2, Comparative Example 1, Example 3, Example 2, and Example 1.

[0056] Figure 5 shows the stability test images of Examples 1-3 and Comparative Examples 1-2 in week 12, where from left to right they correspond to Comparative Example 2, Comparative Example 1, Example 3, Example 2, and Example 1.

[0057] Figure 6 shows the stability test images of Examples 1-3 in week 16, where from left to right they correspond to Examples 3, 2, and 1.

[0058] Figure 7 shows the stability test images of Examples 1-3 in week 20, where from left to right they correspond to Examples 3, 2, and 1. Detailed Implementation

[0059] Example 1: A hydrophobic surface treatment process for powder, comprising the following steps: 1. Add 600g of organic solvent (ethanol) to a beaker, then add 600g of powder (titanium dioxide, grade: CR50, Ishihara Sangyo Co., Ltd.), and stir at 600rpm for 5min using a dispersion mixer to obtain a primary dispersion; 2. Process the primary dispersion twice using a high-pressure homogenizer (GEA, Pandaplus) at 400bar pressure to obtain a secondary dispersion; 3. Take 1kg of the secondary dispersion and place it in a dispersion mixer at 300rpm. 4. The dispersion was re-dispersed at high speed, and 15g of surface treatment agent (triethoxyoctylsilane) was added simultaneously. The mixture was stirred at 300-400rpm for 30min to perform hydrophobic treatment; 5. The treated dispersion was placed in a hot air dryer (Shanghai Biaocheng Experimental Instrument Co., Ltd., DHG-9240A), dried at 80℃ for 2h, and then heat-treated at 120℃ for 6h to remove the solvent simultaneously; 6. The surface-treated powder after removing the organic solvent was pulverized using a hammer mill (Baroin hammer mill) to break up the agglomerates formed during the drying process and obtain the treated powder.

[0060] Example 2: A hydrophobic surface treatment process for powder, comprising the following steps: 1. Add 600g of organic solvent (ethanol) to a beaker, then add 600g of powder (titanium dioxide, grade: CR50, Ishihara Sangyo Co., Ltd.), and stir at 600rpm for 5min using a dispersion mixer to obtain a primary dispersion; 2. Process the dispersed titanium dioxide dispersion twice using a high-pressure homogenizer (GEA, Pandaplus) at 600bar pressure to obtain a secondary dispersion; 3. Take 1kg of the secondary dispersion, place it in a dispersion mixer, and redisperse it at 300rpm. Add 16.5g of surface treatment agent (15g of polydimethylsiloxane and 1.5g of aminopropylsilane), stir at 300-400rpm for 30min to perform hydrophobic treatment; 4. Place the treated dispersion into a hot air dryer (Shanghai Biaocheng Experimental Instrument Co., Ltd., DHG-9240A), dry at 80℃ for 2h, and then heat treat at 140℃ for 6h to remove the solvent simultaneously; 5. Use a hammer mill (Baroin hammer mill) to pulverize the surface-treated powder after removing the organic solvent, break up the agglomerates formed during the drying process, and obtain the treated powder.

[0061] Example 3: A hydrophobic surface treatment process for powder, comprising the following steps: 1. Add 600g of organic solvent (ethanol) to a beaker, then add 600g of powder (titanium dioxide, grade: CR50, Ishihara Sangyo Co., Ltd.), and stir using a dispersion mixer at 800rpm for 5min to obtain a primary dispersion; 2. Process the primary dispersion twice using a high-pressure homogenizer (GEA, Pandaplus) at 800bar to obtain a secondary dispersion; 3. Take 1kg of the secondary dispersion and place it in a dispersion mixer at 300rpm. 4. The dispersion was redispersed at a speed of m, and 15g of surface treatment agent (hydrodimethylsiloxane) was added simultaneously. The mixture was stirred at 300-400rpm for 30min to perform hydrophobic treatment; 5. The treated dispersion was placed in a hot air dryer (Shanghai Biaocheng Experimental Instrument Co., Ltd., DHG-9240A), dried at 80℃ for 2h, and then heat-treated at 140℃ for 6h to remove the solvent simultaneously; 6. The surface-treated powder after removing the organic solvent was pulverized using a hammer mill (Baroin hammer mill) to break up the agglomerates formed during the drying process and obtain the treated powder.

[0062] Example 4: A hydrophobic surface treatment process for powder, comprising the following steps: 1. Add 600g of organic solvent (ethanol) to a beaker, then add 600g of powder (mica, MicaS-8, Huajing Company, particle size 9-15μm), and stir at 600rpm for 5min using a dispersion mixer to obtain a primary dispersion; 2. Process the primary dispersion twice using a high-pressure homogenizer (GEA, Pandaplus) at 600bar to obtain a secondary dispersion; 3. Take 1kg of the secondary dispersion and place it in a dispersion mixer at 300rpm. 4. The dispersion was re-dispersed at 1 pm speed, and 15 g of surface treatment agent (triethoxyoctylsilane) was added. The mixture was stirred at 300-400 rpm for 30 min to perform hydrophobic treatment; 5. The treated dispersion was placed in a hot air dryer (Shanghai Biaocheng Experimental Instrument Co., Ltd., DHG-9240A), dried at 80℃ for 2 h, and then heat-treated at 120℃ for 6 h to remove the solvent simultaneously; 6. The surface-treated powder after removing the organic solvent was pulverized using a hammer mill (Baroin hammer mill) to break up the agglomerates formed during the drying process and obtain the treated powder.

[0063] Example 5: A hydrophobic surface treatment process for powder, comprising the following steps: 1. Add 600g of organic solvent (ethanol) to a beaker, then add 600g of powder (synthetic mica, YM-601, Baili Company, particle size 5-7μm), and stir at 600rpm for 5min using a dispersion mixer to obtain a primary dispersion; 2. Process the primary dispersion twice using a high-pressure homogenizer (GEA, Pandaplus) at 600bar to obtain a secondary dispersion; 3. Take 1kg of the secondary dispersion and place it in a dispersion mixer at 300rpm. 4. The dispersion was re-dispersed at 1 pm speed, and 15 g of surface treatment agent (triethoxyoctylsilane) was added. The mixture was stirred at 300-400 rpm for 30 min to perform hydrophobic treatment; 5. The treated dispersion was placed in a hot air dryer (Shanghai Biaocheng Experimental Instrument Co., Ltd., DHG-9240A), dried at 80℃ for 2 h, and then heat-treated at 120℃ for 6 h to remove the solvent simultaneously; 6. The surface-treated powder after removing the organic solvent was pulverized using a hammer mill (Baroin hammer mill) to break up the agglomerates formed during the drying process and obtain the treated powder.

[0064] Example 6: A hydrophobic surface treatment process for powder, comprising the following steps: 1. Add 600g of organic solvent (ethanol) to a beaker, then add 600g of powder (synthetic mica, BL-9023, Baili Company, particle size 10-20μm), and stir at 600rpm for 5min using a dispersion mixer to obtain a primary dispersion; 2. Process the primary dispersion twice using a high-pressure homogenizer (GEA, Pandaplus) at 600bar to obtain a secondary dispersion; 3. Take 1kg of the secondary dispersion and place it in a dispersion mixer at 300... 4. The dispersion was redispersed at rpm, and 15g of surface treatment agent (triethoxyoctylsilane) was added simultaneously. The mixture was stirred at 300-400rpm for 30min to perform hydrophobic treatment. 5. The treated dispersion was placed in a hot air dryer (Shanghai Biaocheng Experimental Instrument Co., Ltd., DHG-9240A) and dried at 80℃ for 2h, followed by heat treatment at 120℃ for 6h to remove the solvent simultaneously. 6. The surface-treated powder after removing the organic solvent was pulverized using a hammer mill (Baroin hammer mill) to break up the agglomerates formed during the drying process and obtain the treated powder.

[0065] Comparative Example 1: A hydrophobic surface treatment process for a powder, comprising the following steps: 1. Add 600g of organic solvent (ethanol) to a beaker, then add 600g of powder (synthetic mica, BL-9023, Baili Company, particle size 10-20μm), and stir at 600rpm for 5min using a dispersion mixer to obtain a primary dispersion; 2. Take 1kg of the primary dispersion, place it in a dispersion mixer and redisperse at 300rpm, while adding 15g of surface treatment agent (triethoxyoctylsilane), and stir at 300-400rpm for 30min to perform hydrophobic treatment; 3. Place the treated dispersion into a hot air dryer (Shanghai Biaocheng Experimental Instrument Co., Ltd., DHG-9240A), dry at 80℃ for 2h, and then heat-treat at 120℃ for 6h to remove the solvent simultaneously; 4. Use a hammer mill (Baroin hammer mill) to pulverize the surface-treated powder after removing the organic solvent, breaking up the agglomerates formed during the drying process to obtain the treated powder.

[0066] Comparative Example 2: A hydrophobic surface treatment process for a powder, comprising the following steps: 1. Adding 600g of organic solvent (ethanol) to a beaker, followed by 600g of powder (titanium dioxide, grade: CR50, Ishihara Sangyo Co., Ltd.), and stirring at 600rpm for 5min using a dispersion mixer to obtain a primary dispersion; 2. Processing the primary dispersion twice using a high-pressure homogenizer (GEA, Pandaplus) at 100bar pressure to obtain a secondary dispersion; 3. Taking 1kg of the secondary dispersion and placing it in a dispersion mixer at 300rpm... 4. The dispersion was re-dispersed at high speed, and 15g of surface treatment agent (triethoxyoctylsilane) was added simultaneously. The mixture was stirred at 300-400rpm for 30min to perform hydrophobic treatment; 5. The treated dispersion was placed in a hot air dryer (Shanghai Biaocheng Experimental Instrument Co., Ltd., DHG-9240A), dried at 80℃ for 2h, and then heat-treated at 120℃ for 6h to remove the solvent simultaneously; 6. The surface-treated powder after removing the organic solvent was pulverized using a hammer mill (Baroin hammer mill) to break up the agglomerates formed during the drying process and obtain the treated powder.

[0067] Comparative Example 3 describes a hydrophobic surface treatment process for a powder, comprising the following steps: 1. Add 600g of organic solvent (ethanol) to a beaker, then add 600g of powder (mica, MicaS-8, Huajing Company, particle size 9-15μm), and stir at 600rpm for 5min using a dispersion mixer to obtain a primary dispersion; 2. Take 1kg of the primary dispersion, place it in a dispersion mixer, and redisperse it at 300rpm, while simultaneously adding 15g of surface treatment agent (triethoxyoctylsilane), and stir at 300-400rpm for 30min to perform hydrophobic treatment; 3. Place the treated dispersion into a hot air dryer (Shanghai Biaocheng Experimental Instrument Co., Ltd., DHG-9240A), dry it at 80℃ for 2h, and then heat-treat it at 120℃ for 6h to remove the solvent simultaneously; 4. Use a hammer mill (Baroin hammer mill) to pulverize the surface-treated powder after removing the organic solvent, breaking up the agglomerates formed during the drying process to obtain the treated powder.

[0068] Comparative Example 4: A hydrophobic surface treatment process for a powder, comprising the following steps: 1. Add 600g of organic solvent (ethanol) to a beaker, then add 600g of powder (synthetic mica, YM-601, Baili Company, particle size 5-7μm), and stir at 600rpm for 5min using a dispersion mixer to obtain a primary dispersion; 2. Process the primary dispersion twice using a high-pressure homogenizer (GEA, Pandaplus) at 100bar to obtain a secondary dispersion; 3. Take 1kg of the secondary dispersion and place it in a dispersion mixer at 300rpm. 4. The dispersion was re-dispersed at 1 pm speed, and 15 g of surface treatment agent (triethoxyoctylsilane) was added. The mixture was stirred at 300-400 rpm for 30 min to perform hydrophobic treatment; 5. The treated dispersion was placed in a hot air dryer (Shanghai Biaocheng Experimental Instrument Co., Ltd., DHG-9240A), dried at 80℃ for 2 h, and then heat-treated at 120℃ for 6 h to remove the solvent simultaneously; 6. The surface-treated powder after removing the organic solvent was pulverized using a hammer mill (Baroin hammer mill) to break up the agglomerates formed during the drying process and obtain the treated powder.

[0069] Comparative Example 5 describes a hydrophobic surface treatment process for a powder, comprising the following steps: 1. Add 600g of organic solvent (ethanol) to a beaker, then add 600g of powder (synthetic mica, BL-9023, Baili Company, particle size 10-20μm), and stir at 600rpm for 5min using a dispersion mixer to obtain a primary dispersion; 2. Take 1kg of the primary dispersion, place it in a dispersion mixer and redisperse at 300rpm, while adding 15g of surface treatment agent (triethoxyoctylsilane), and stir at 300-400rpm for 30min to perform hydrophobic treatment; 3. Place the treated dispersion in a hot air dryer (Shanghai Biaocheng Experimental Instrument Co., Ltd., DHG-9240A), dry at 80℃ for 2h, and then heat-treat at 120℃ for 6h to remove the solvent simultaneously; 4. Use a hammer mill (Baroin hammer mill) to pulverize the surface-treated powder after removing the organic solvent, breaking up the agglomerates formed during the drying process to obtain the treated powder.

[0070] Performance Testing Method 1: Dispersion Stability Test: The hydrophobically treated titanium dioxide (75%), cyclopentadiene siloxane (21%), and PEG-9 polydimethylsiloxane oxyethyldimethylsiloxane (4%) from Examples 1-3 and Comparative Examples 1-2 were mixed and stirred at 300 rpm for 30 minutes using a dispersion mixer. The mixture was then homogenized three times using a high-pressure homogenizer (600 bar) to prepare a dispersion. The dispersion was stored in a 25°C incubator and periodically tested using a Brookfield viscometer (DV2TL). Viscosity (cP) changes were measured using a V, 64 rotor, 12 rpm to assess dispersion stability. Test data are listed in Table 1, and test images are listed in Figures 1-7. Blank areas indicate no test was performed. As can be seen from Table 1 and Figure 1, the dispersions of Examples 1-3 showed smooth viscosity changes and no stratification within 20 weeks, demonstrating excellent dispersion stability. Comparative Example 1 (without high-pressure homogenization) showed stratification at week 8, and Comparative Example 2 (low-pressure homogenization) showed stratification at week 12, with dispersion stability significantly worse than the Examples.

[0071] Table 1

[0072] 2. Preparation of samples for skin feel evaluation (cushion foundation application): The titanium dioxide treated in Examples 1-3 and Comparative Examples 1-2 was used to prepare liquid foundation according to the following formula, and each sample (15g / piece) was immersed in a sponge to make a cushion foundation.

[0073] The formula for cushion foundation is shown in Table 2 (mass fraction / %).

[0074] Table 2

[0075] Preparation method of cushion foundation: Weigh components 1-7 (oil phase A) and components 14-20 (aqueous phase B) in different containers and stir thoroughly until homogeneous; place oil phase A in a high-speed homogenizer and stir, slowly add component 8, and disperse at 3500 rpm for 5 minutes; keep stirring at 3500-4000 rpm and slowly add components 9-13, and continue to disperse for 5 minutes until homogeneous; slowly add the homogeneous and transparent aqueous phase B to the above oil-powder dispersion system and emulsify at 4000-4500 rpm for 10 minutes; defoam the emulsified liquid foundation, and then immerse it (15g / piece) in a sponge to make cushion foundation.

[0076] Evaluation method: Thirty female subjects aged 23-40 were selected. After using the cushion foundation, they were rated on four indicators: "applicability, smoothness, adherence, and makeup lasting power" (1-5 points, with higher scores indicating higher satisfaction). The average evaluation score was calculated.

[0077] The evaluation results are shown in Table 3. The cushion foundations of Examples 1-3 are significantly better than those of Comparative Examples 1-2 in terms of spreadability, smoothness, adherence, makeup retention, and overall evaluation. This shows that the hydrophobic surface treatment method of the present invention can effectively improve the skin feel of cosmetics.

[0078] Table 3

[0079] 3. Using skin feel evaluation (loose powder application), the powders processed in Examples 4-6 and Comparative Examples 3-5 were formulated according to the loose powder formula (mass fraction / %) in Table 4 to obtain loose powder samples.

[0080] Powder preparation method: Accurately weigh 1-12 (A), put them into a food mixer (SFM-700SS_HANIL) and mix them thoroughly to obtain a first mixture; weigh ingredients 13-17 (B) in separate containers, and mix them thoroughly after ingredient 16 is completely dissolved to obtain a second mixture; add the thoroughly mixed second mixture to the thoroughly mixed first mixture in 3 portions, mixing after each addition, and repeat this operation 3 times; continue mixing for 30 seconds; use an atomizer (Baroin, Hammermill) for pulverization.

[0081] Table 4

[0082] Evaluation method: Thirty female subjects aged 23-40 were selected. After using the cushion foundation, they were rated on four indicators: "applicability, smoothness, adherence, and makeup lasting power" (1-5 points, with higher scores indicating higher satisfaction). The average evaluation score was calculated.

[0083] The evaluation results are shown in Table 5. The application example foundation is significantly better than the control example in terms of spreadability, smoothness, adherence, makeup lasting power and overall evaluation, which shows that the hydrophobic surface treatment method of the present invention can effectively improve the skin feel of cosmetics.

[0084] Table 5

Claims

1. A hydrophobic surface treatment process for powders, characterized in that, The process includes the following steps: mixing the powder with an organic solvent to obtain a primary dispersion; dispersing the primary dispersion under a pressure greater than 100 bar to obtain a secondary dispersion; surface treating the secondary dispersion with a surface treatment agent, followed by solvent removal, heat treatment, and pulverization to obtain the treated powder.

2. The hydrophobic surface treatment process according to claim 1, characterized in that, The average particle size of the powder is <1 μm.

3. The hydrophobic surface treatment process according to claim 2, characterized in that, The average particle size of the powder is 0.01-0.31 μm.

4. The hydrophobic surface treatment process according to claim 1, characterized in that, The pressure is ≥200 bar.

5. The hydrophobic surface treatment process according to claim 3 or 4, characterized in that, The pressure is 200-1000 bar.

6. The hydrophobic surface treatment process according to claim 5, characterized in that, The secondary dispersion was obtained by homogenization.

7. The hydrophobic surface treatment process according to claim 6, characterized in that, The weight ratio of the powder to the solvent is 1:(0.2-5).

8. The hydrophobic surface treatment process according to claim 7, characterized in that, The amount of the surface treatment agent is 0.1-20 wt% of the secondary dispersion.

9. The hydrophobic surface treatment process according to claim 1 or 8, characterized in that, The surface treatment agent includes at least one of the following types: siloxanes, amino acids, fatty acids, phospholipids, esters, and titanium compounds.

10. A cosmetic product, characterized in that, Includes the powder processed according to any one of claims 1-9.

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