Method for producing solid powder cosmetic

Abstract

To provide a method capable of improving filling performance and mold-releasing ability over conventional methods, and capable of forming more vivid surface uneven patterns on a solid powder cosmetic than conventional methods.SOLUTION: The present invention relates to a method for producing a solid powder cosmetic. The method comprises: a preliminary molding step of filling a mold having an open top and a bottom with an uneven shape with a slurry containing at least water and a powder to obtain a preliminary molded body; a molding step of pressing the preliminary molded body and removing a part of water contained in the preliminary molded body to obtain a molded body; a freezing step of cooling the molded body to obtain a frozen body; and a moisture removal step of removing the remaining water from the frozen body to obtain the solid powder cosmetic. In the molding step, water is removed from the preliminary molded body in a pressed state so that the water content in the preliminary molded body becomes 16 mass% or more and 35 mass% or less. The slurry contains 35 mass% or more of water and 1 mass% or more of a powder whose contact angle with water at 25°C is 15° or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a solid powder cosmetic. [Background technology]

[0002] The wet method is known as one of the methods for producing solid powder cosmetics such as eye shadow, foundation, etc. The wet method is a method in which a slurry containing raw materials for the solid powder cosmetic is filled into a mold, and then the solvent is removed from the slurry.

[0003] For example, Patent Document 1 describes a method for producing a solid powder cosmetic by cooling a paste containing a thermoreversible polysaccharide to turn it into a jelly-like substance, followed by heat treatment. The document also describes that this production method results in a solid powder cosmetic with a creamy texture. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-251956 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, efforts have been made to improve the design of solid powder cosmetics by forming patterns on the surface of the cosmetics. However, the manufacturing method described in Patent Document 1 can cause pinholes to form inside or on the surface of the solid cosmetic, which can make it difficult to form a clear textured pattern. Furthermore, the manufacturing method described in the same document uses a paste with low fluidity, which makes it difficult to fill the paste into a molding die and also difficult to release from the molding die, which also makes it difficult to form a clear textured pattern. Therefore, an object of the present invention is to provide a method for producing a solid powder cosmetic that has better filling and releasability than conventional methods and is capable of forming a clear uneven pattern. [Means for solving the problem]

[0006] The present invention includes a preforming step of filling a mold having an open top and an uneven bottom with a slurry containing at least water and powder to obtain a preform; a molding step of pressing the preform to remove a portion of the water contained in the preform to obtain a molded body; a freezing step of cooling the molded body to obtain a frozen body; and a moisture removal step of removing the remaining water from the frozen body to obtain a solid powder cosmetic. In one embodiment, in the molding step, it is preferable to remove the water from the preform while pressing the preform so that the water content in the preform is 16% by mass or more and 35% by mass or less. In one embodiment, the slurry preferably contains 35% by mass or more of the water and 1% by mass or more of the powder having a contact angle with water of 15° or more at 25°C. [Effects of the Invention]

[0007] The present invention provides a method that can improve filling properties and releasability compared to conventional methods. The present invention also provides a method that can form a more distinct uneven pattern on the surface of a solid powder cosmetic product than conventional methods. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a schematic diagram of one embodiment of a solid powder cosmetic produced by the production method of the present invention. [Figure 2] 2(a) to 2(d) are schematic diagrams sequentially showing steps of a manufacturing method according to one embodiment of the present invention. [Figure 3] 3(a) to 3(d) are schematic diagrams sequentially showing steps of a manufacturing method according to one embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram showing a method for measuring the contact angle. [Figure 5]FIG. 5(a) is a 3D analytical image of the surface of the solid powder cosmetic obtained in Example 3, and FIG. 5(b) is a 3D analytical image of the surface of the solid powder cosmetic obtained in Comparative Example 2. [Figure 6] FIG. 6(a) is a photograph of the cosmetic compact used to evaluate the strength of the solid powder cosmetics obtained in Examples 1 to 5 in a closed state, and FIG. 6(b) is a photograph of the cosmetic compact in an open state. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention relates to a method for producing a solid powder cosmetic. A "solid powder cosmetic" refers to a cosmetic that is solid at room temperature (25°C) and does not soften or melt when heated to a temperature higher than room temperature.

[0010] FIG. 1 shows a schematic diagram of a solid powder cosmetic 10, which is the subject of the manufacturing method of the present invention. The solid powder cosmetic 10 has a flat rectangular parallelepiped shape. The solid powder cosmetic 10 is used by being contained in a shallow, dish-shaped container (hereinafter also referred to as a "middle dish") 11. The solid powder cosmetic 10 has an uneven surface. Specifically, the solid powder cosmetic 10 of this embodiment has alternating ridges 10a and grooves 10b that extend continuously in one direction on its upper surface. The upper part of the cross section of the solid powder cosmetic 10 in the thickness direction has, for example, a triangular wave shape or a sawtooth shape. The lower part of the cross section of the solid powder cosmetic 10 in the thickness direction has a continuous shape. In either case, the peaks of the ridges 10a and the valleys of the grooves 10b have clear, linear shapes formed by intersecting planes. Furthermore, the slopes between the tops of the ridges 10a and the valleys of the grooves 10b are smooth, and no irregularities are observed due to cracks or the like in the solid powder cosmetic 10. According to the manufacturing method of the present invention, it is possible to manufacture a solid powder cosmetic 10 having a clear uneven pattern formed on its surface, as shown in Figure 1. Hereinafter, a method for producing a solid powder cosmetic will be described based on a preferred embodiment with reference to the drawings. The manufacturing method of the present invention includes the following steps in this order: Pre-molding process ·Molding process ·Freezing process ·Moisture removal process Each of these steps will be described below.

[0011] [Preforming process] In the preforming step, as shown in FIGS. 2(a) and 2(b), a slurry 22 is filled into a forming die 21 to obtain a preform 23. The mold 21 has a bottom 21a and side walls 21b extending from the periphery of the bottom 21a. The side walls 21b extend along the entire periphery of the bottom 21a. The mold 21 is open at the top, with the upper ends of the side walls 21b defining an opening. Specifically, the bottom of the mold 21 has an uneven shape. The mold 21 of this embodiment has alternating ridges 21c and grooves 21d extending continuously in one direction formed on its bottom. The cross section of the mold 21 in the thickness direction has a sawtooth shape. Specifically, in the mold 21, the peaks of the ridges 21c and the valleys of the grooves 21d are clearly linear, formed by intersecting planes. Furthermore, the slope between the peaks of the ridges 21c and the valleys of the grooves 21d is smooth. The material constituting the mold 21 is preferably an easily deformable material from the viewpoint of facilitating removal of the frozen body from the mold 21 in the freezing step described below. Examples of such materials include silicone rubber, urethane rubber, ethylene-propylene rubber, ethylene-vinyl acetate rubber, butadiene rubber, styrene-butadiene rubber, natural rubber, isoprene rubber, nitrile rubber, fluororubber, and chloroprene rubber. Of these, silicone rubber is preferred because it does not harden easily near the freezing temperature described below, and furthermore, friction during demolding is small, making it easy to remove the frozen body from the mold.

[0012] The slurry 22 contains at least water and powder and is fluid at a temperature at which the preforming step is carried out, such as room temperature. The slurry 22 preferably contains a predetermined amount of water. This provides the slurry 22 with appropriate fluidity, improving its fillability into the forming die 21. When the slurry 22 is filled into the forming die 21, the slurry 22 is more likely to spread throughout the entire interior of the forming die 21. As a result, the occurrence of pinholes due to imperfect filling is suppressed. From the viewpoint of further enhancing these advantages, the slurry 22 preferably contains 35% by mass or more of water, more preferably 38% by mass or more, even more preferably 40% by mass or more, and even more preferably 45% by mass or more. From the same viewpoint, the slurry 22 preferably contains 70% by mass or less of water, more preferably 68% by mass or less, and even more preferably 65% by mass or less.

[0013] In this embodiment, the powder is used for the purpose of imparting color and gloss to the solid powder cosmetic product, which is the target of the manufacturing method of the present invention, and for the purpose of improving the feel in use and impact resistance. Examples of such powders include extender pigments, coloring pigments, luster pigments, and organic resin powders.

[0014] Examples of extender pigments include silicic acid, silicic anhydride, magnesium silicate, talc, sericite, boron nitride, mica, glass, synthetic phlogopite, kaolin, clay, bentonite, bismuth oxychloride, magnesium oxide, aluminum oxide, calcium sulfate, barium sulfate, magnesium sulfate, calcium carbonate, aluminum silicate, magnesium silicate, silica, and alumina, as well as composite powders thereof.

[0015] Examples of color pigments include metal oxides such as titanium oxide, zinc oxide, yellow iron oxide, red iron oxide, black iron oxide, Prussian blue, ultramarine, chromium oxide, and chromium hydroxide; metal complexes such as manganese violet and cobalt titanate; carbon black; synthetic organic pigments such as Red No. 3, Red No. 104, Red No. 106, Red No. 201, Red No. 202, Red No. 204, Red No. 205, Red No. 220, Red No. 218, Red No. 223, Red No. 226, Red No. 227, Red No. 228, Red No. 230, Red No. 401, Red No. 405, Red No. 505, Orange No. 201, Orange No. 203, Orange No. 204, Orange No. 205, Yellow No. 4, Yellow No. 5, Yellow 401, Blue No. 1, and Blue 404; and natural organic dyes such as β-carotene, caramel, and paprika pigments.

[0016] Examples of luster pigments include those in which the surface of plate-like powders such as mica, synthetic phlogopite, glass, silica and alumina is coated with colorants such as titanium oxide, iron oxide, silicon oxide, Prussian blue, chromium oxide, tin oxide, chromium hydroxide, gold, silver and organic pigments; and those obtained by cutting raw film rolls such as polyethylene terephthalate-polymethyl methacrylate laminated powder, polyethylene terephthalate-aluminum vapor-deposited powder and polyethylene terephthalate-gold vapor-deposited laminated powder into any desired shape.

[0017] Examples of organic resin powders include polyethylene powder, polypropylene powder, polymethyl methacrylate powder, nylon powder, polytetrafluoroethylene powder, silicone powder, silicone rubber powder, silk powder, urethane powder, cellulose powder, starch powder, and polyethylene fluoride.

[0018] There are no limitations on the size, shape, etc. of these powders, and they can be used as they are, or they can be subjected to a hydrophobic or hydrophilic treatment by a conventional method before use.

[0019] The hydrophobic treatment is not limited to any particular treatment that is commonly used for cosmetic powders, and may be a dry treatment, a wet treatment, or the like, using a surface treatment agent such as a fluorine-based compound, a silicone-based compound, a metal soap, an amino acid-based compound, lecithin, an alkylsilane, an oil, or an organic titanate.

[0020] Specific examples of surface treatment agents include fluorine-based compounds such as perfluoropolyether, perfluoroalkyl phosphate ester, perfluoroalkylalkoxysilane, and fluorine-modified silicone; silicone-based compounds such as dimethylpolysiloxane, methylhydrogenpolysiloxane, cyclic silicone, organopolysiloxane modified with one or both ends by a trialkoxy group, crosslinked silicone, silicone resin, fluorine-modified silicone resin, and acrylic-modified silicone; metal stones such as aluminum stearate, aluminum myristate, zinc stearate, and magnesium stearate; soap; amino acid compounds such as proline, hydroxyproline, alanine, glycine, sarcosine, glutamic acid, aspartic acid, lauroyl lysine, lysine and their derivatives, and acylated amino acids; lecithin and hydrogenated lecithin; alkyl silanes such as methyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, and triethoxycaprylylsilane; oils such as polyisobutylene, waxes, oils and fatty acids; and organic titanates such as isopropyl triisostearoyl titanate.

[0021] In this embodiment, it is preferable to use a powder having a contact angle with water of 15° or more at 25°C (hereinafter also referred to as "highly water-repellent powder") as at least a portion of the powder contained in the slurry 22. A large contact angle with water means high water repellency, and by using a highly water-repellent powder, it becomes possible to easily remove some of the water from the preform so that a predetermined amount of water is contained in the preform in the molding process described below. From the viewpoint of making these advantages even more pronounced, it is even more preferable that the highly water-repellent powder has a contact angle with water of 20° or more at 25°C. The larger the contact angle of the highly water-repellent powder, the better, but the achievable upper limit is less than 180°. Examples of highly water-repellent powders that can be used include extender pigments such as talc and boron nitride, and organic resin powders, as well as powders that have been given water repellency by hydrophobic treatment (hereinafter also referred to as "hydrophobic treated powders").Highly water-repellent powders can be used alone or in combination of two or more different types.From the viewpoint of ease of handling, it is preferable to use talc and / or hydrophobic treated powders, and it is particularly preferable to use talc. The method for measuring the contact angle with water will be explained in the examples below.

[0022] The slurry 22 preferably contains a highly water-repellent powder. This makes it easier to remove a portion of the water from the preform in the molding step described below. To further enhance this advantage, the slurry 22 preferably contains 1% by mass or more of the highly water-repellent powder, more preferably 3% by mass or more, and even more preferably 5% by mass or more. From the same perspective, the slurry 22 preferably contains 50% by mass or less of the highly water-repellent powder, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0023] It is preferable that the slurry 22 further contains a polyhydric alcohol. In the present invention, the polyhydric alcohol is used for the purposes of improving the dispersibility of the highly water-repellent powder and oil in water, imparting a moist feel to the solid powder cosmetic that is the target of the manufacturing method of the present invention, and improving adhesion to the skin and impact resistance. As such a polyhydric alcohol, it is preferable to use at least one selected from dihydric alcohols and trihydric alcohols.

[0024] Examples of dihydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butylene glycol, 1,2-pentylene glycol, 1,3-pentylene glycol, 1,4-pentylene glycol, 1,5-pentylene glycol, hexylene glycol, and dipropylene glycol. An example of the trihydric alcohol is glycerin. These alcohols may be used alone or in combination of two or more different types.

[0025] Among these polyhydric alcohols, from the viewpoint of ease of handling, it is preferable to use dihydric alcohols such as 1,2-propanediol, dipropylene glycol, and 1,3-butylene glycol, and trihydric alcohols such as glycerin and diglycerin.

[0026] The content of polyhydric alcohol in slurry 22 is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, from the viewpoints of improving the dispersibility of the highly water-repellent powder and oil in water, and of making it easier to impart a moist feel to the solid powder cosmetic and improving adhesion to the skin and impact resistance. From the same viewpoints, the content of polyhydric alcohol in slurry 22 is preferably 15% by mass or less, more preferably 12% by mass or less, and even more preferably 10% by mass or less.

[0027] Furthermore, in the present invention, the mass ratio of polyhydric alcohol to powder (amount of polyhydric alcohol / amount of powder) is preferably 3 or more, more preferably 3.5 or more, and even more preferably 4 or more, from the viewpoints of improving the dispersibility of the highly water-repellent powder and oil in water, imparting a moist feel to the solid powder cosmetic, and further improving adhesion to the skin and impact resistance. Also, from the same viewpoint, the mass ratio of polyhydric alcohol to powder is preferably 30 or less, more preferably 28 or less, and even more preferably 25 or less. The mass ratio of polyhydric alcohol to powder does not substantially change between the state of the slurry and the state of the desired solid powder cosmetic.

[0028] It is preferable that the slurry 22 further contains an oil. In this embodiment, the oil is used for the purposes of imparting a moist feel to the solid powder cosmetic, which is the target of the manufacturing method of the present invention, and improving adhesion to the skin and impact resistance. Such oils are preferably liquid oils that are non-volatile at 25°C, such as hydrocarbon oils, ester oils, ether oils, and silicone oils.

[0029] Examples of non-volatile hydrocarbon oils include straight-chain or branched-chain hydrocarbon oils such as squalane, liquid paraffin, liquid isoparaffin, polybutene, hydrogenated polydecene, and petrolatum.

[0030] Examples of the ester oil include monoester oil, diester oil, triester oil, and tetraester oil.

[0031] Examples of monoester oils include monoesters of aliphatic or aromatic monocarboxylic or dicarboxylic acids having 2 to 24 carbon atoms. Specific examples include cetyl 2-ethylhexanoate, cetyl octanoate, isononyl isononanoate, isotridecyl isononanoate, hexyl laurate, isopropyl myristate, octyldodecyl myristate, myristyl myristate, 2-hexyldecyl myristate, isopropyl palmitate, octyl palmitate, 2-hexyldecyl palmitate, butyl stearate, isocetyl stearate, isocetyl isostearate, decyl oleate, isodecyl benzoate, octyl methoxycinnamate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, 2-ethylhexyl succinate, 2-hexyldecyl adipate, and alkyl benzoates (C12 to C15).

[0032] Examples of diester oils include diesters of dicarboxylic acids having 3 to 18 carbon atoms and difatty acid esters of polyhydric alcohols. Specific examples include propylene glycol dicaprylate, neopentyl glycol dicaprate, glycol distearate, propylene glycol diisostearate, glyceryl diisostearate, polyglyceryl diisostearate, glyceryl monomyristate monoisostearate, glycerin di-2-heptylundecanoate, di-2-ethylhexyl succinate, diisopropyl sebacate, diisostearyl malate, ethylene glycol di-2-ethylhexanoate, diisobutyl adipate, di-2-heptylundecyl adipate, and di-2-ethylhexyl sebacate.

[0033] Examples of triester oils include tri-fatty acid esters of trihydric or higher polyhydric alcohols, and specific examples include glycerin trimyristate, glycerin triisopalmitate, glycerin tri-2-heptylundecanoate, trimethylolpropane triethylhexanoate, trimethylolpropane trioctanoate, glyceryl tri(caprylate / caprate), glycerin trioleate, glycerin tri-2-ethylhexanoate (triethylhexanoin), and glycerin triisostearate.

[0034] Examples of tetraester oils include tetra-fatty acid esters of tetrahydric or higher polyhydric alcohols, and specific examples include pentaerythritol tetra(behenate / benzoate / ethylhexanoate), pentaerythritol tetraethylhexanoate, pentaerythritol tetraoctanoate, and pentaerythritol tetra-2-ethylhexanoate.

[0035] The ether oils include dialkyl ethers, and specific examples thereof include dihexyl ether, dicaprylyl ether, and cetyl-1,3-dimethylbutyl ether.

[0036] Examples of silicone oils include crosslinked methylpolysiloxane, network methylpolysiloxane, dimethylpolysiloxane, methyltrimethicone, dimethylcyclopolysiloxane, methylphenylpolysiloxanes such as diphenylsiloxyphenyltrimethicone, and higher alcohol-modified organopolysiloxanes. The oil agent may be used alone or in combination of two or more different types.

[0037] Among these oils, from the viewpoint of ease of handling, it is particularly preferable to use hydrocarbon oils such as hydrogenated polydecene, ester oils such as isotridecyl isononanoate, polyglyceryl diisostearate, diisostearyl malate, glyceryl tri(caprylate / caprate), and triethylhexanoin, and methylphenyl polysiloxanes such as diphenylsiloxyphenyl trimethicone.

[0038] From the viewpoints of making it easier to impart a moist feel to the solid powder cosmetic and further improving adhesion to the skin and impact resistance, the content of the oil in the slurry 22 is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more. From the same viewpoints, the content of the oil in the slurry 22 is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0039] Furthermore, in the present invention, the mass ratio of oil to powder (amount of oil / amount of powder) is preferably 2 or more, more preferably 5 or more, even more preferably 10 or more, and even more preferably 15 or more, from the viewpoint of imparting a moist feel to the solid powder cosmetic and further improving adhesion to the skin and impact resistance. From the same viewpoint, the mass ratio of oil to powder is preferably 50 or less, more preferably 45 or less, and even more preferably 40 or less. The mass ratio of oil to powder does not change substantially between the state of the slurry and the state of the desired solid powder cosmetic.

[0040] In addition to the various ingredients described above, the slurry 22 may contain ingredients commonly used in cosmetics. Examples of such ingredients include surfactants, lower alcohols, preservatives, antioxidants, thickeners such as polyacrylate crosspolymer-6, pH adjusters, fragrances, UV absorbers, moisturizers, blood circulation promoters, cooling agents, antiperspirants, disinfectants, and skin activators. These ingredients may be used alone or in combination. These ingredients do not necessarily need to be included in the slurry 22. When the slurry 22 contains these ingredients, the amount used is preferably from 0.01% by mass to 10% by mass, respectively, in the slurry 22.

[0041] Once the above raw materials are prepared, they are mixed to obtain a slurry 22. The mixing may be performed by adding the raw materials all at once or sequentially in any order. The mixing may be performed using a known mixer such as a homomixer or a disperser mixer. The viscosity of the slurry 22 thus obtained is preferably 10 mPa·s or more, more preferably 100 mPa·s or more, and even more preferably 700 mPa·s or more, from the viewpoints of the fillability into the molding die and the ability to remove moisture from the preform (described below). Furthermore, the viscosity of the slurry 22 is preferably 40,000 mPa·s or less, more preferably 30,000 mPa·s or less, and even more preferably 25,000 mPa·s or less. The "viscosity" referred to here is a value measured at 25°C using a B-type viscometer (TVB-10 model viscometer) manufactured by Toki Sangyo Co., Ltd. 2(b), the slurry 22 is filled into the forming die 21 to obtain a preformed body 23. The filling can be performed, for example, by pouring the slurry 22 into the forming die 21 through the opening of the forming die 21.

[0042] [Molding process] Next, as shown in FIGS. 2(c) and 2(d), a molding step is carried out. In the molding process, the preform 23 is first pressed by the pressing tool 24. This spreads the slurry 22 constituting the preform 23 throughout the inside of the mold 21, transferring the uneven shape of the mold 21 to the bottom of the preform 23, and removing pinholes from the preform 23. Furthermore, the feel and impact resistance of the solid powder cosmetic can be improved. To further enhance these advantages, the pressing pressure is preferably 0.01 MPa or more, more preferably 0.05 MPa or more, and even more preferably 0.08 MPa or more. From the same perspective, the pressing pressure is preferably 1 MPa or less, more preferably 0.7 MPa or less, and even more preferably 0.4 MPa or less. The pressing force can be measured, for example, by attaching a pressure detection sensor (not shown), such as a load cell, to the pressing tool 24. From the same viewpoint as above, the pressing time is preferably 0.1 seconds or more, more preferably 0.5 seconds or more, and even more preferably 1 second or more. From the same viewpoint, the pressing time is preferably 25 seconds or less, more preferably 20 seconds or less, and even more preferably 15 seconds or less.

[0043] In the molding step, it is preferable to press the preformed body 23 together with the pressing auxiliary tool 25 while the upper surface of the preformed body 23 is covered with the pressing auxiliary tool 25. In other words, it is preferable to press the preformed body 23 so that the preformed body 23 and the pressing tool 24 do not come into direct contact with each other. This makes it possible to prevent the slurry 22 constituting the preformed body 23 from adhering to the pressing tool 24. Furthermore, for example, when removing part of the water from the preformed body 23 via the pressing tool 24, it is possible to prevent raw materials other than water from being unintentionally removed. The pressing aid 25 is preferably made of a liquid-permeable material. Examples of such materials include paper, cloth, and film with holes for allowing liquid to pass through. One of these materials may be used alone as the pressing aid 25, or two or more may be used in combination. From the viewpoint of ensuring the strength of the pressing aid 25, it is preferable to use cloth, and among these, it is particularly preferable to use nonwoven fabric made of thermoplastic resin fibers. Examples of such nonwoven fabrics include spunbond nonwoven fabrics, meltblown nonwoven fabrics, spunlace nonwoven fabrics, needle-punched nonwoven fabrics, air-through nonwoven fabrics, and nonwoven fabrics made by laminating two or more of these nonwoven fabrics.

[0044] Pressing by pressing tool 24 is preferably performed in a state where the entire upper surface of preform 23 is covered with pressing auxiliary tool 25. For example, pressing auxiliary tool 25 may be made of a nonwoven fabric having a size larger than the opening of mold 21, and preform 23 can be pressed together with pressing auxiliary tool 25 by lowering pressing tool 24 from a state where pressing tool 24 and pressing auxiliary tool 25 are positioned above mold 21.

[0045] Next, as shown in Figure 2(d), the water contained in the preformed body 23 is removed to obtain a molded body 26. One of the features of the manufacturing method of the present invention is that only a portion of the water is removed, rather than all of the water contained in the preformed body 23. Removing a portion of the water has the advantages of making it easier to remove the frozen body from the mold 21 in the freezing step described below, and of suppressing deformation of the solid powder cosmetic when removing water from the frozen body. The water contained in the preform 23 can be removed, for example, by a suction mechanism provided in the pressing tool 24 at room temperature and atmospheric pressure. Any commonly used suction mechanism can be used without any particular limitation. In this embodiment, a plurality of suction holes 24a are provided in the pressing surface (the surface facing the object to be pressed) of the pressing tool 24 so as to extend in the thickness direction of the pressing tool 24. Each of the suction holes 24a opens on the upper surface of the pressing tool 24 and is connected to a suction source (not shown) such as a suction pump. The water contained in the preform 23 can be removed by operating the suction source to reduce the pressure inside the suction holes 24a. The water removal is preferably performed while the preform 23 is pressed. This is because the water seeps out of the preform 23 due to the pressing, making the water removal easier.

[0046] In the molding step, it is preferable to remove water from the preformed body 23 so that the moisture content in the preformed body 23 falls within a predetermined range. Specifically, in the freezing step described below, from the viewpoint of sufficiently freezing the molded body 26 and making it easier to remove the frozen body from the molding die 21, it is preferable to remove water so that the moisture content in the preformed body 23 is 16% by mass or more, more preferably 18% by mass or more, and even more preferably 21% by mass or more. Furthermore, when removing water from the frozen body in the moisture removing step described below, from the viewpoint of preventing deformation of the solid powder cosmetic due to evaporation of water remaining in the frozen body, it is preferable to remove water so that the moisture content in the preformed body 23 is 35% by mass or less, more preferably 32% by mass or less, and even more preferably 30% by mass or less.

[0047] In order to keep the moisture content in the preform 23 within the above range, it is preferable to adjust the suction pressure and suction time of the suction mechanism. Specifically, from the viewpoint of successfully removing water contained in the preform 23 without placing an excessive load on the suction mechanism, the suction pressure is preferably −90 kPa or more, more preferably −70 kPa or more, and even more preferably −50 kPa or more, expressed as a gauge pressure. From the same viewpoint, the suction pressure is preferably −5 kPa or less, more preferably −10 kPa or less, and even more preferably −20 kPa or less, expressed as a gauge pressure. From the viewpoint of successfully removing water contained in the preform 23 without placing an excessive load on the suction mechanism, the suction time is preferably 0.01 seconds or more, more preferably 0.1 seconds or more, and even more preferably 0.5 seconds or more. From the same viewpoint, the suction time is preferably 25 seconds or less, more preferably 20 seconds or less, and even more preferably 15 seconds or less.

[0048] [Freezing process] Next, as shown in FIG. 3( a), a freezing step is performed. The freezing step can be performed by, for example, placing the molded body 26 in a known freezing device without pressing the molded body 26. For example, the molded body 26 can be placed in the freezing device while being held in the mold 21. By subjecting the molded body 26 to the freezing step, freezing progresses from the outer surface of the molded body 26 toward the inside, causing ice crystals to grow. As the freezing step progresses, all of the water remaining in the molded body 26 turns to ice, and a frozen body 27 can be obtained. One of the features of the manufacturing method of the present invention is that the frozen body 27 is obtained by cooling the molded body 26. The frozen body 27 has a higher hardness than the molded body 26, which improves its releasability. This has the advantage of making it easier to remove the frozen body 27 from the mold 21 while maintaining the shape imparted to the frozen body 27 in the process described below.

[0049] A known freezing device can be used for freezing. Specifically, for example, a method of placing the molded body 26 in a freezer, a method of bringing the mold 21 into contact with a solid such as a cooled metal plate, or a method of immersing the mold 21 in a cooled liquid can be used. In any of these methods, it is preferable to freeze the molded body 26 while it is placed in the mold 21. This allows a frozen body 27 to be obtained while maintaining the shape given to the molded body 26.

[0050] The freezing temperature in the freezing step is not particularly limited as long as it is at a temperature at which the water in the molded body 26 can freeze to produce ice. From the viewpoint of successfully obtaining the frozen body 27, the freezing temperature is preferably −5° C. or lower, more preferably −10° C. or lower, and even more preferably −15° C. or lower. From the same viewpoint, the freezing temperature is preferably −50° C. or higher, more preferably −40° C. or higher, and even more preferably −30° C. or higher. The freezing time in the freezing step may be adjusted appropriately depending on the freezing temperature. When the freezing temperature is adjusted to the above range, freezing is preferably carried out for 15 minutes or more, more preferably 30 minutes or more, and even more preferably 60 minutes or more. In the same case, freezing is preferably carried out for 72 hours or less, more preferably 48 hours or less, and even more preferably 24 hours or less.

[0051] 3(b), the frozen body 27 is removed from the forming mold 21. The frozen body 27 can be removed from the forming mold 21 by deforming the forming mold 21 by an external force to shift the frozen body 27, and then picking up the frozen body 27 with, for example, a suction pad.

[0052] 3(c), the removed frozen body 27 is turned upside down and placed in the inner tray 11. The storage space of the inner tray 11 has a shape complementary to the outer shape of the frozen body 27.

[0053] [Moisture removal process] Next, as shown in Figure 3(d), a moisture removal step is carried out. The moisture removal step can be carried out, for example, by placing the frozen body 27 in a known moisture removal device. By subjecting the frozen body 27 to the moisture removal step, water is removed from the frozen body 27. In this way, the solid powder cosmetic 10, which is the target of the manufacturing method of the present invention, can be obtained.

[0054] For example, methods such as heat drying and vacuum drying can be used to remove moisture. When heat drying is used to remove moisture, a known drying device can be used. Specifically, methods such as blowing hot air, blowing dry gas, heating with a heater, and irradiating with infrared rays can be used.

[0055] When the frozen body 27 is dried by heating, there are no particular restrictions on the heating temperature, as long as it is capable of removing the water from the frozen body 27. From the perspective of successfully obtaining the solid powder cosmetic 10, the heating temperature is preferably 40°C or higher, more preferably 50°C or higher, and even more preferably 55°C or higher. From the same perspective, the heating temperature is preferably 200°C or lower, more preferably 100°C or lower, and even more preferably 80°C or lower. The drying time in the moisture removal step may be adjusted appropriately depending on the type of drying apparatus and heating temperature. When the heating temperature is adjusted to the above range, drying is preferably carried out for 0.5 hours or more, more preferably 1 hour or more, and even more preferably 2 hours or more. In the same case, drying is preferably carried out for 72 hours or less, more preferably 48 hours or less, and even more preferably 24 hours or less.

[0056] When the frozen body 27 is vacuum-dried, the pressure in the system is preferably 200 Pa or less from the viewpoint of successfully obtaining the solid powder cosmetic 10. From the same viewpoint, the pressure in the system is preferably 50 Pa or more. The temperature during vacuum drying is preferably below freezing, between -60°C and -20°C.

[0057] The above manufacturing method produces the desired solid powder cosmetic 10. In the steps shown in Figures 2 and 3, a mold 21 with ridges 21c and grooves 21d formed therein is used, so the produced solid powder cosmetic 10 has ridges and grooves that extend continuously in one direction on its surface. The steps shown in Figures 2 and 3 produce a solid powder cosmetic 10 with a clear textured pattern formed on its surface.

[0058] The solid powder cosmetic produced by the production method of the present invention can be used in cosmetic methods, for example, by applying it to the human body for cosmetic purposes. Specifically, it can be applied to the human lips, eyelids, cheeks, etc. Application can be carried out using an applicator such as a puff or brush, or can be carried out directly with the fingers without using an applicator.

[0059] While the present invention has been described above based on its preferred embodiments, the present invention is not limited to these embodiments. For example, in the above embodiments, a mold having ridges and grooves at the bottom is used, but the shape of the bottom is not limited to this and can be any shape that corresponds to the shape of the solid powder cosmetic to be produced. [Example]

[0060] The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, "%" means "% by mass."

[0061] Example 1 (1) Preforming process A slurry was obtained by mixing water, powder, oil, polyhydric alcohol, and thickener in the ratio shown in Table 1 below. Specifically, the oil was first heated to 60°C to obtain a uniform oil phase. Separately from this operation, a water phase was obtained by adding the polyhydric alcohol and thickener to water heated to 60°C. This water phase was added to the oil phase and mixed using a homomixer at 6000 rpm for 5 minutes. An emulsion was then obtained by cooling with water while stirring with a spatula. Powder was added to the obtained emulsion and kneaded for 5 minutes using a disper mixer to obtain a slurry. The viscosity of the obtained slurry at 25°C was as shown in Table 1. Details of each raw material shown in Table 1 are as follows. The contact angle of the powder was measured using the following method.

[0062] *1: Talc (contact angle 20°) (Talc JA-46R, Asada Flour Milling Co., Ltd.) *2: Sericite (contact angle 0°) (SERICITE FSE-S, Sanshin Mining Co., Ltd.) *3: Titanium oxide coated mica (contact angle 0°) (COSMETICA SUPER WHITE N-8000S, CQV Co., Ltd.) *4: Yellow iron oxide (contact angle 0°) (TAROX Synthetic Iron Oxide LL-100P, Titan Kogyo Co., Ltd.) *5: Red iron oxide (contact angle 0°) (TAROX synthetic iron oxide R-516P, Titan Kogyo Co., Ltd.) *6: Triethylhexanoin (TIO, Nisshin Oillio Group Co., Ltd.) *7: Polyacrylate crosspolymer-6 (SEPIMAX ZEN, SEPPIC SA)

[0063] Next, the slurry was poured into a mold having an open top and an uneven bottom, by the procedure shown in FIG. 2(b), to obtain a preform.

[0064] (2) Molding process As shown in Figure 2(c), the entire top surface of the preform was covered with a pressing aid (a nonwoven fabric made of rayon and polypropylene (PP) / polyethylene (PE) mixed fabric, 0.2 mm thick), and the preform was pressed with a pressing tool as shown in Figure 2(d). While maintaining the pressed state, water was removed from the preform using a suction mechanism attached to the pressing tool to obtain a molded product. The water content in the preform was measured using the following method. The results are shown in Table 1. The pressure and time during pressing and the pressure and time during suction were as shown in Table 1.

[0065] (3) Freezing process The molded body was placed in a freezer set at -17°C for 3 hours while still in the mold. This resulted in freezing the molded body and obtaining a frozen body as shown in Figure 3(a). The resulting frozen body was removed from the mold as shown in Figure 3(b). After the removed frozen body was inverted upside down, it was placed in the storage space of the inner plate as shown in Figure 3(c).

[0066] (4) Moisture removal process The frozen mass was heated and dried to remove water, as shown in Figure 3(d). Specifically, a paste (SEPIMAX ZEN 1.6% aqueous solution) was applied to an aluminum tray measuring 27 mm long x 27 mm wide and 4 mm deep, and the frozen mass was placed on top of the tray. Drying was carried out by leaving the tray in a thermostatic chamber at 60°C for 12 hours. In this way, the desired solid powder cosmetic was obtained.

[0067] [Examples 2 to 5 and Comparative Examples 1 to 4] In Example 1, the compounding ratios of water, powder, oil, polyhydric alcohol, and thickener were changed to the values shown in Table 1. In addition, the pressure and time during pressing and the time during suction were changed to the values shown in Table 1. Other than this, the intended solid powder cosmetic was obtained in the same manner as in Example 1.

[0068] 〔evaluation〕 The contact angles of the powders used in the examples and comparative examples were measured by the following method. 3D analytical images were obtained using a VR-5000 (manufactured by Keyence Corporation) for the solid powder cosmetics obtained in Example 3 and Comparative Example 2. The obtained 3D analytical images are shown in Figures 5(a) and (b). During the steps of the Examples and Comparative Examples, the viscosity of the resulting slurry was measured by the method described above. In the molding steps of the Examples and Comparative Examples, the amount of water in the preform was measured by the following method. During the processes of the Examples and Comparative Examples, the filling property and releasability were evaluated by the following methods. Furthermore, the solid powder cosmetics obtained in the Examples and Comparative Examples were evaluated for shape retention and pinholes by the following methods. Furthermore, the solid powder cosmetics obtained in the Examples were evaluated for strength and texture by the following methods. The results are shown in Tables 1 and 2 below.

[0069] [Contact angle of powder] The powders used in the examples and comparative examples were filled into a metal dish with outer diameters X, Y, and Z = 28.1 mm x 56.9 mm x 5 mm. The filling was performed so that the surface would be flush with the top surface of the dish after molding. Next, a pressing aid (medicine wrapping paper, small paraffin, manufactured by Hakuaisha) was placed on the top surface of the dish, and the sample was molded at a pressure of 0.2 MPa to obtain a molded sample. The obtained molded sample was placed in a fully automatic contact angle meter (Model: Dmo-702 Camra: SA-Co1, manufactured by KYOWA), and 0.8 μL of purified water was dropped onto the sample. The drop was performed using a 28G poly(tetrafluoroethylene) needle. The contact angle was measured 100 ms after the drop. The contact angle is indicated by the "θ" portion in Figure 4.

[0070] [Water content in preform] First, the mass of the mold used to produce the solid powder cosmetic was measured in advance. Next, in the freezing step, the mass of the molded product was measured while it was still in the mold. After that, the molded product was cooled and frozen, and the mass of the frozen product was measured while it was still in the molded product. Then, the water content in the pre-molded product was calculated based on the following formula (1). Water content in preform (%) = {(mass of preform and mold after freezing) - (mass of mold)} / {(mass of preform and mold before freezing) - (mass of mold)} × 100 (1)

[0071] [Fillability] In the process of pouring the slurry into a mold to obtain a preform (see Figures 2(a) and (b)), five expert panelists visually observed whether the slurry spread within the mold within five taps when the mold was tapped, and then evaluated the filling ability of the slurry according to the following evaluation criteria. The number of people who answered "good" is shown in Table 1.

[0072] [Evaluation criteria] ◯: Good filling properties (the slurry spreads easily in the mold having an uneven surface). ×: Poor filling properties (the slurry does not spread over the uneven mold).

[0073] [Mold releasability] When the frozen body was removed from the mold during the freezing process, the inside of the mold was visually inspected by five expert panelists, who then evaluated the releasability according to the following criteria. The number of people who answered "Good" is shown in Table 1.

[0074] [Evaluation criteria] ◯: Almost no frozen body remained inside the mold. ×: A large amount of frozen material remained inside the mold.

[0075] [Shape retention] The surfaces of the solid powder cosmetics obtained in the Examples and Comparative Examples were visually observed by five expert panelists, and then the shape retention was evaluated according to the following evaluation criteria. The totals of scores 1 to 3 are shown in Table 1.

[0076] [Evaluation criteria] 3: The shape did not change even after the frozen body was dried. A clear uneven pattern was formed on the surface of the solid powder cosmetic. 2: The solid powder cosmetic material shrunk as the frozen body dried, and the uneven pattern was deformed. 1: The surface of the solid powder cosmetic melted as the frozen body dried, making the uneven pattern unclear.

[0077] [Pinhole] The surfaces of the solid powder cosmetics obtained in the Examples and Comparative Examples were visually inspected by five expert panelists, who then evaluated the presence or absence of pinholes according to the following evaluation criteria. The number of people who answered "Good" is shown in Table 1.

[0078] [Evaluation criteria] ○: No pinholes were observed. ×: Pinholes were observed.

[0079] [Strength] The solid powder cosmetic obtained in the example was placed in an inner tray and placed in a cosmetic compact (an ABS container with external dimensions of 40 × 46.4 × 12.9 mm, with a thickness of 2 mm below the inner tray) as shown in Figures 6(a) and 6(b). The cosmetic compact was then repeatedly dropped onto an acrylic plate (thickness 1 cm) from a position 40 cm vertically above the acrylic plate. The strength was evaluated based on the number of times it took for the solid powder cosmetic to develop defects such as chips, breaks, or cracks. The higher the number of times, the stronger the solid powder cosmetic. The results are shown in Table 2.

[0080] [Texture] The solid powder cosmetic preparations obtained in the examples were applied to the skin of five panelists. The number of people who answered that the moist feeling and adhesion upon application were "good" was evaluated. The number of people who answered "good" is shown in Table 2.

[0081] [Table 1]

[0082] [Table 2]

[0083] As is clear from the results shown in Figure 5(a), a clear uneven pattern was formed on the surface of the solid powder cosmetic obtained in Example 3. In contrast, as is clear from the results shown in Figure 5(b), the uneven pattern was partially indistinct for the solid powder cosmetic obtained in Comparative Example 2. Furthermore, as is clear from the results shown in Table 1, the solid powder cosmetic preparations obtained in the Examples had improved packing properties, releasability, and shape retention compared to the solid powder cosmetic preparations obtained in the Comparative Examples. Furthermore, as is clear from the results shown in Table 2, the solid powder cosmetic preparations obtained in the Examples had improved strength and texture. [Explanation of symbols]

[0084] 10. Solid powder cosmetics 11 Medium Plate 21 Molding mold 22 Slurry 23 Preform 24 Pressing tool 25 Pressure aids 26 Molded body 27 Frozen body

Claims

1. a preforming step of filling a mold having an open top and an uneven bottom with a slurry containing at least water and powder to obtain a preform; a molding step of pressing the preform to remove a portion of the water contained in the preform to obtain a molded body; a freezing step of cooling the molded body to obtain a frozen body; a moisture removal step of removing the remaining water from the frozen body to obtain a solid powder cosmetic, In the molding step, the water in the preform is removed while the preform is being pressed so that the water content in the preform is 16% by mass or more and 35% by mass or less; The slurry contains 35% by mass or more of the water and 1% by mass or more of the powder having a contact angle with water of 15° or more at 25°C.

2. The manufacturing method according to claim 1 , wherein in the molding step, the preform is pressed together with the pressing auxiliary tool while the upper surface of the preform is covered with the pressing auxiliary tool.

3. Using the slurry further containing a polyhydric alcohol, The method according to claim 1 or 2, wherein a mass ratio of the polyhydric alcohol to the powder (amount of polyhydric alcohol / amount of powder) is 3 or more and 30 or less.

4. Using the slurry further containing an oil agent, The method according to claim 1 or 2, wherein a mass ratio of the oil to the powder (amount of oil / amount of powder) is 2 or more and 50 or less.

5. The manufacturing method according to claim 1 or 2, wherein the mold is made of an easily deformable material.

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