Water-in-oil solid cosmetic

Abstract

To provide a water-in-oil solid cosmetic that exhibits excellent moldability, a pleasant feel, appropriate hardness at room temperature when the cosmetic is used, and excellent quality retention even at high temperatures such as in summer. [Solution] A water-in-oil solid cosmetic composition containing (A) an oil component, (B) a surfactant, (C) a wax component, and (D) water, wherein the (A) oil component is an oil component containing hydrocarbon oil and ester oil, the (B) surfactant is a surfactant containing polyglyceryl polyricinoleate, and the (C) wax component is at least one wax selected from the group consisting of sunflower seed wax and candelilla wax.

Description

Technical Field

[0001] The present invention relates to a water-in-oil solid cosmetic. More specifically, the present invention relates to a water-in-oil solid cosmetic that can be suitably used for, for example, skin care cosmetics, body care cosmetics, hair cosmetics, and the like.

Background Art

[0002] As a solid water-containing cosmetic that gives a refreshing feeling and a moist feeling to the skin when applied to the skin, a solid water-containing cosmetic containing a lipophilic polyglycerol fatty acid ester, beeswax, sunflower seed wax, and rice bran wax has been proposed (for example, see Patent Document 1).

[0003] The solid water-containing cosmetic is said to have good stability over time even when the water content is high and to give a refreshing feeling to the skin when applied to the skin. However, in recent years, there has been a demand for the development of a water-in-oil solid cosmetic that has excellent moldability, good usability, has an appropriate hardness at room temperature where the cosmetic is used, and has excellent quality retention even when the temperature is high in summer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of the above prior art, and an object thereof is to provide a water-in-oil solid cosmetic that has excellent moldability, good usability, has an appropriate hardness at room temperature where the cosmetic is used, and has excellent quality retention even when the temperature is high in summer.

Means for Solving the Problems

[0006] The present invention relates to a water-in-oil solid cosmetic composition comprising (A) an oil component, (B) a surfactant, (C) a wax component, and (D) water, wherein the (A) oil component is an oil component containing hydrocarbon oil and ester oil, the (B) surfactant is a surfactant containing polyglyceryl polyricinoleate, and the (C) wax component is at least one wax selected from the group consisting of sunflower seed wax and candelilla wax. [Effects of the Invention]

[0007] The present invention provides a water-in-oil solid cosmetic composition that exhibits excellent moldability, a pleasant feel, appropriate hardness at room temperature when the cosmetic is used, and excellent quality retention even at high temperatures such as in summer. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram illustrating the concept of the water-in-oil solid cosmetic composition of the present invention. [Modes for carrying out the invention]

[0009] As described above, the water-in-oil solid cosmetic composition of the present invention is a water-in-oil solid cosmetic composition containing (A) an oil component, (B) a surfactant, (C) a wax component, and (D) water, wherein the (A) oil component is an oil component containing hydrocarbon oil and ester oil, the (B) surfactant is a surfactant containing polyglyceryl polyricinoleate, and the (C) wax component is at least one wax selected from the group consisting of sunflower seed wax and candelilla wax. Because the water-in-oil solid cosmetic composition of the present invention has the above-described structure, it has excellent moldability, a good feel to use, has appropriate hardness at room temperature, and has excellent quality retention.

[0010] In this invention, "feel" refers to the refreshing, volatile sensation felt when the water-in-oil solid cosmetic is applied to the skin, and that it spreads smoothly on the skin's surface. Furthermore, "quality retention" refers to the property of maintaining quality even when the room temperature is high, such as in summer. In this invention, it means that no abnormalities in appearance are observed even when the room temperature is 50°C.

[0011] (A) Oil component Oil components are essential for preparing water-in-oil solid cosmetic compositions. Oil components containing hydrocarbon oils and ester oils are used as the oil component. In the present invention, since hydrocarbon oils and ester oils are used in combination, the water-in-oil solid cosmetic composition of the present invention has excellent moldability, a good feel to use, appropriate hardness at room temperature, and excellent quality retention. The oil component may consist only of hydrocarbon oils and ester oils, or other oil components may be included as long as they do not hinder the objectives of the present invention. From the viewpoint of obtaining a water-in-oil solid cosmetic composition that has excellent moldability, a good feel to use, appropriate hardness at room temperature, and excellent quality retention, the content of hydrocarbon oils and ester oils in the oil component is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass.

[0012] Examples of hydrocarbon oils include petrolatum, mineral oil, and squalane, but the present invention is not limited to these examples.

[0013] Vaseline is obtained by refining hydrocarbon compounds extracted from petroleum. Examples of Vaseline include white Vaseline, yellow Vaseline, and Propeto, but the present invention is not limited to these examples. Examples of mineral oil include liquid paraffin and liquid isoparaffin, but the present invention is not limited to these examples. Examples of squalane include shark-derived squalane, olive-derived squalane, and sugarcane-derived squalane, but the present invention is not limited to these examples.

[0014] Among hydrocarbon oils, since water-in-oil solid cosmetics are used on human skin, naturally derived hydrocarbon oils are preferred, naturally derived squalane is more preferred, and animal-derived squalanes such as shark-derived squalane and plant-derived squalanes such as olive-derived squalane and sugarcane-derived squalane are even more preferred.

[0015] In this invention, "naturally derived" ingredients refer to extracts from plants and animals, as well as ingredients obtained by processing such as purification of such extracts.

[0016] Examples of ester oils include fatty acid alkyl esters and fatty acid polyhydric alcohol esters, but the present invention is not limited to these examples. Ester oils may be of natural origin or obtained by synthesis. Synthetically obtained ester oils are preferably synthesized using naturally derived components.

[0017] Examples of fatty acid alkyl esters include isocetyl isostearate, isononyl isononanoate, cetyl 2-ethylhexanoate, cetyl octanoate, isononyl isononanoate, triethyl citrate, 2-ethylhexyl succinate, isocetyl stearate, butyl stearate, diisopropyl sebacate, di-2-ethylhexyl sebacate, isopropyl palmitate, 2-ethylhexyl palmitate, 2-hexyldecyl palmitate, 2-heptylundecyl palmitate, isopropyl myristate, octyldodecyl myristate, 2-hexyldecyl myristate, myristyl myristate, hexyldecyl dimethyloctanoate, ethyl laurate, hexyl laurate, diisostearyl malate, and isostearyl myristate, but the present invention is not limited to these examples. These fatty acid alkyl esters may be used individually or in combination of two or more types.

[0018] Examples of fatty acid polyhydric alcohol esters include polyfatty acid glyceryls, which are esters of multiple fatty acids such as glyceryl tri-2-ethylhexylate [triethylhexanoin], glyceryl triisostearate, glyceryl tri(caprylic / capric acid), glyceryl triisopalmitate, glyceryl di-2-heptylundecanoate, and glyceryl trimyristate, with one molecule of glycerin; trimethylolpropane triisostearate; ethylene glycol di-2-ethylhexanoate; trimethylolpropane tri-2-ethylhexanoate; pentaerythritol tetra-2-ethylhexanoate; and neopentyl glycol dicaprate. However, the present invention is not limited to these examples. These fatty acid polyhydric alcohol esters may be used individually or in combination of two or more types. In polyfatty acid glyceryl, "polyfatty acid" means that multiple fatty acids are used as raw materials. In the polyfatty acid glyceryls described in the examples above, two or three fatty acids are used as raw materials.

[0019] Among ester oils, fatty acid polyhydric alcohol esters are preferred from the viewpoint of obtaining a water-in-oil solid cosmetic that has excellent moldability, a good feel, appropriate hardness at room temperature, and excellent quality retention. Since water-in-oil solid cosmetics are used on human skin, fatty acid glyceryl is more preferred, and tri(caprylic / capric acid)glyceryl and tri-2-ethylhexyl glyceryl [triethylhexanoin] are even more preferred.

[0020] In the present invention, from the perspective of obtaining an oil-in-water solid cosmetic that is excellent in moldability, has a good usability, has appropriate hardness at room temperature, and is excellent in quality retention and usability, it is preferable to use a hydrocarbon oil and an ester oil in combination. The mass ratio of the hydrocarbon oil to the ester oil (hydrocarbon oil / ester oil) is preferably 10 / 90 or more, more preferably 20 / 80 or more, still more preferably 25 / 75 or more from the perspective of improving moldability and usability and imparting appropriate hardness to the oil-in-water solid cosmetic at room temperature, and is preferably 90 / 10 or less, more preferably 20 / 80 or less, still more preferably 25 / 75 or less from the perspective of improving the quality retention of the oil-in-water solid cosmetic.

[0021] The total content of the hydrocarbon oil and the ester oil in the oil-in-water solid cosmetic is preferably 25 to 60% by mass, more preferably 30 to 55% by mass from the perspective of obtaining an oil-in-water solid cosmetic that is excellent in moldability, has a good usability, has appropriate hardness at room temperature, and is excellent in quality retention.

[0022] (B) Surfactant As the surfactant, a surfactant containing polyglyceryl polyricinoleate is used. In the present invention, since a surfactant containing polyglyceryl polyricinoleate is used, an oil-in-water solid cosmetic having appropriate hardness at room temperature can be obtained.

[0023] Polyglyceryl polyricinoleate is an ester of polyricinoleic acid and polyglycerol. The average degree of polymerization of polyglycerol is preferably 2 to 10, more preferably 4 to 6 from the perspective of improving moldability. The average degree of polymerization of polyglycerol is the average degree of polymerization of polyglycerol determined from the hydroxyl value based on the end group analysis method. The glycerol used as a raw material for polyglyceryl polyricinoleate is preferably glycerol derived from natural sources such as plants since the oil-in-water solid cosmetic is used on human skin and the like.

[0024] Examples of polyglyceryl polyricinoleates include polyglyceryl-3, polyglyceryl-6, and polyglyceryl-10, but the present invention is not limited to these examples. These polyglyceryl polyricinoleates may be used individually or in combination of two or more types. The numbers at the end of the polyglyceryl polyricinoleates listed in the examples above represent the average degree of polymerization of polyglycerin. Among the polyglyceryl polyricinoleates, polyglyceryl-6 is preferred from the viewpoint of obtaining a water-in-oil type solid cosmetic having appropriate hardness at room temperature.

[0025] Polyglyceryl polyricinoleate is readily available commercially, and examples include products manufactured by Sakamoto Pharmaceutical Co., Ltd., such as CR-350H, CR-310, CR-500, and CRS-75 (polyglyceryl-6 polyricinoleate). However, the present invention is not limited to these examples.

[0026] The amount of polyglyceryl polyricinoleate per 100 parts by mass of oil component is preferably 3 to 20 parts by mass, more preferably 5 to 15 parts by mass, from the viewpoint of obtaining a water-in-oil solid cosmetic composition that has excellent moldability, a good feel, appropriate hardness at room temperature, and excellent quality retention.

[0027] In the present invention, nonionic surfactants other than polyglyceryl polyricinoleate (hereinafter referred to as "other nonionic surfactants") may be included in the water-in-oil type solid cosmetic composition, to the extent that the objectives of the present invention are not hindered.

[0028] Other nonionic surfactants include, for example, nonionic fatty acid (poly)glyceryls and nonionic sorbitan fatty acid esters, but the present invention is not limited to these examples.

[0029] Nonionic fatty acid (poly)glyceryl refers to esters of one fatty acid and one glycerol, and esters of multiple fatty acids and multiple glycerols.

[0030] Examples of nonionic fatty acid (poly)glycerides include glyceryl stearate (HLB value: 3), glyceryl isostearate (HLB value: 4), polyglyceryl-2 stearate (HLB value: 5), polyglyceryl-4 stearate (HLB value: 6), polyglyceryl-2 isostearate (HLB value: 5), polyglyceryl-4 isostearate (HLB value: 8), polyglyceryl-2 triisostearate (HLB value: 3), polyglyceryl-10 tristearate (HLB value: 8), and oleic acid Examples of fatty acid polyglycerides include polyglyceryl-2 (HLB value: 6), polyglyceryl-2 caprylate (HLB value: 8), polyglyceryl-2 sesquicaprylate (HLB value: 8), glyceryl behenate (HLB value: 3.4), glyceryl myristate (HLB value: 3.5), self-emulsifying glyceryl monostearate (HLB value: 6), diglyceryl isostearate (HLB value: 5.5), and diglyceryl myristate (HLB value: 7.6), but the present invention is not limited to these examples.

[0031] Examples of nonionic sorbitan fatty acid esters include sorbitan sesquiisostearate (HLB value: 6), sorbitan sesquioleate (HLB value: 6), sorbitan palmitate (HLB value: 7), sorbitan isostearate (HLB value: 8), and sorbitan stearate (HLB value: 8), but the present invention is not limited to these examples.

[0032] The HLB value of the other nonionic surfactant is preferably 3 to 8, from the viewpoint of obtaining a water-in-oil solid cosmetic composition that has excellent moldability, a good feel, appropriate hardness at room temperature, and excellent quality retention. Furthermore, among other nonionic surfactants, from the viewpoint of obtaining a water-in-oil type solid cosmetic that has excellent moldability, a good feel, appropriate hardness at room temperature, and excellent quality retention, nonionic fatty acid polyglyceryls with an HLB value of 3 to 8, such as polyglyceryl-2 triisostearate (HLB value: 3), glyceryl stearate (HLB value: 3), polyglyceryl-2 stearate (HLB value: 5), polyglyceryl-4 stearate (HLB value: 6), polyglyceryl-2 isostearate (HLB value: 5), and glyceryl behenate (HLB value: 3.4), and nonionic sorbitan fatty acid esters with an HLB value of 3 to 8, such as sorbitan sesquiisostearate (HLB value: 6), are preferred, and polyglyceryl-2 triisostearate (HLB value: 3) is more preferred.

[0033] When polyglyceryl polyricinoleate is used in combination with other nonionic surfactants, the mass ratio of polyglyceryl polyricinoleate to other nonionic surfactants (polyglyceryl polyricinoleate / other nonionic surfactant) is preferably 55 / 45 to 85 / 15, from the viewpoint of obtaining a water-in-oil type solid cosmetic that has excellent moldability, a good feel, appropriate hardness at room temperature, and excellent quality retention.

[0034] From the viewpoint of obtaining a water-in-oil solid cosmetic composition that has excellent moldability, a good feel, moderate hardness at room temperature, and excellent quality retention, the content of polyglyceryl polyricinoleate and other nonionic surfactants in the surfactant is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass.

[0035] Furthermore, the surfactant content in the water-in-oil solid cosmetic composition is preferably 1 to 10% by mass, more preferably 2 to 8% by mass, from the viewpoint of obtaining a water-in-oil solid cosmetic composition that has excellent moldability, a good feel, appropriate hardness at room temperature, and excellent quality retention.

[0036] (C) Wax component As the wax component, at least one wax selected from the group consisting of sunflower seed wax and candelilla wax is used. In the present invention, since at least one wax selected from the group consisting of sunflower seed wax and candelilla wax is used in this way, an oil-in-water type solid cosmetic can be obtained that has excellent moldability, a good feel to use, appropriate hardness at room temperature, and excellent quality retention. Sunflower seed wax and candelilla wax may be used individually or in combination. Among the wax components, sunflower seed wax is preferred from the viewpoint of obtaining an oil-in-water type solid cosmetic that has excellent moldability, a good feel to use, appropriate hardness at room temperature, and excellent quality retention.

[0037] From the viewpoint of obtaining a water-in-oil solid cosmetic composition that has excellent moldability, a good feel, moderate hardness at room temperature, and excellent quality retention, the content of at least one wax selected from the group consisting of sunflower seed wax and candelilla wax in the wax component is preferably 85 to 100% by mass, more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass, and even more preferably 100% by mass.

[0038] The wax component may include at least one wax component other than sunflower seed wax and candelilla wax, selected from the group consisting of sunflower seed wax and candelilla wax, to the extent that it does not hinder the objectives of the present invention (hereinafter referred to as "other wax components").

[0039] Other wax components mentioned above include, for example, naturally derived wax components such as Japanese wax, rice bran wax, cotton wax, shellac wax, beeswax, gelac wax, privet wax, and lanolin; petroleum-based wax components such as paraffin and microcrystalline wax components; and polyolefin-based wax components such as polyethylene wax components. However, the present invention is not limited to these examples. These wax components may be used individually or in combination of two or more types. Among these wax components, naturally derived wax components are preferred because water-in-oil solid cosmetics are used on human skin and the like.

[0040] Generally, carnauba wax is used as a wax in cosmetics. However, when carnauba wax is used as a wax component, it is difficult or impossible to solidify water-in-oil solid cosmetics at room temperature. Furthermore, even when carnauba wax is included in the wax component, depending on the amount of carnauba wax used, it tends to be difficult or impossible to solidify water-in-oil solid cosmetics at room temperature.

[0041] The amount of wax component per 100 parts by mass of oil component is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, from the viewpoint of obtaining an oil-in-water solid cosmetic that has excellent moldability, a good feel, appropriate hardness at room temperature, and excellent quality retention, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, from the viewpoint of obtaining an oil-in-water solid cosmetic that has excellent moldability, a good feel, appropriate hardness at room temperature, and excellent quality retention.

[0042] The wax component content in the water-in-oil solid cosmetic composition is preferably 5% by mass or more, more preferably 6% by mass or more, from the viewpoint of obtaining a water-in-oil solid cosmetic composition that has excellent moldability, a good feel, appropriate hardness at room temperature, and excellent quality retention, and preferably 10% by mass or less, more preferably 9% by mass or less, from the viewpoint of obtaining a water-in-oil solid cosmetic composition that has excellent moldability, a good feel, appropriate hardness at room temperature, and excellent quality retention.

[0043] (D)Water Water is an ingredient that improves the usability of water-in-oil solid cosmetics. The water can be any type that can be used in water-in-oil solid cosmetics, and is not particularly limited. Examples of water include pure water, purified water, deionized water, distilled water, and tap water, but the present invention is not limited to these examples.

[0044] From the viewpoint of improving the usability of the water-in-oil type solid cosmetic composition, the amount of water per 100 parts by mass of oil component is preferably 25 to 250 parts by mass, more preferably 30 to 200 parts by mass, and even more preferably 50 to 150 parts by mass.

[0045] The water content in a water-in-oil solid cosmetic composition is preferably 10% by mass or more, more preferably 15% by mass or more, from the viewpoint of improving the usability of the water-in-oil solid cosmetic composition, and preferably 65% ​​by mass or less, more preferably 60% by mass or less, from the viewpoint of improving the feel of use.

[0046] (E) Aqueous components The water-in-oil solid cosmetic composition of the present invention may, if necessary, contain an appropriate amount of aqueous components for purposes such as moisturizing the skin, within a range that does not hinder the objectives of the present invention.

[0047] Examples of aqueous components include moisturizing ingredients such as ethanol, propanediol, butanediol, pentanediol, glycerin, diglycerin, polyglycerin, dipropylene glycol, polyethylene glycol, polyoxyethylene glycerin, polyoxypropylene glyceryl ether, polyoxypropylene diglyceryl ether, polyoxypropylene butyl ether, polyoxyethylene-polyoxypropylene butyl ether, polyoxyethylene methyl glucoside, erythritol, xylitol, maltitol, mannitol, trehalose, and sorbitol. However, the present invention is not limited to these examples. These aqueous components may be used individually or in combination of two or more types.

[0048] (F) Additives The water-in-oil solid cosmetic composition of the present invention may contain, if necessary, an appropriate amount of additives, provided that such additives do not hinder the objectives of the present invention.

[0049] Examples of additives include chelating agents such as ethylenediaminetetraacetate disodium salt; ultraviolet absorbers; ultraviolet scattering agents such as titanium dioxide and fine zinc oxide particles; antioxidants; colorants; thickeners; preservatives; antioxidants; moisturizers; fragrances; pH adjusters; astringents; and texture-improving agents that give a smooth feeling to the skin, such as spherical inorganic powders and spherical organic powders. However, the present invention is not limited to these examples. These additives may be used individually or in combination of two or more types.

[0050] Furthermore, when incorporating a pigment into the water-in-oil type solid cosmetic composition of the present invention, it is preferable to control the amount of the pigment from the viewpoint of improving moldability.

[0051] The water-in-oil solid cosmetic composition of the present invention can be obtained by mixing the aforementioned components and dispersing them to obtain a uniform composition. When dispersing the aforementioned components to obtain a uniform composition, the components may be heated and stirred as necessary.

[0052] The water-in-oil solid cosmetic composition of the present invention may be molded to have a predetermined shape. A water-in-oil solid cosmetic composition having a predetermined shape can be obtained, for example, by placing the water-in-oil solid cosmetic composition of the present invention into a container having a predetermined inner surface shape and molding it. Examples of such containers include resin containers with a predetermined inner surface shape and metal containers with a predetermined inner surface shape, but the present invention is not limited to such examples. The shape of the water-in-oil solid cosmetic composition varies depending on the application of the water-in-oil solid cosmetic composition and cannot be determined in general terms, so it is preferable to determine it appropriately according to the application. Examples of shapes for the water-in-oil solid cosmetic composition include stick shape, plate shape, cylindrical shape, etc., but the present invention is not limited to such examples.

[0053] The water-in-oil solid cosmetic composition of the present invention obtained as described above has excellent moldability, a good feel to use, moderate hardness at room temperature, and excellent quality retention. The reason why the water-in-oil solid cosmetic composition of the present invention has such excellent moldability, a good feel to use, moderate hardness at room temperature, and excellent quality retention is not clear. However, since the water-in-oil solid cosmetic composition of the present invention uses hydrocarbon oil and ester oil as oil components, polyglyceryl polyricinoleate as a surfactant, sunflower seed wax and / or candelilla wax as a wax component, and also contains water, it is presumed that this is due to the water-in-oil solid cosmetic composition of the present invention having a so-called "cardhouse structure".

[0054] More specifically, as shown in Figure 1(a), in the present invention, the water-in-oil solid cosmetic composition is formed under normal conditions by a wax component that creates the wall portion 2 of the card house structure 1. Since the card house structure 1 is stabilized by the wax component that constitutes the wall portion 2, and the oil component 3, surfactant 4, and water 5 are sealed inside the wall portion 2, the water-in-oil solid cosmetic composition of the present invention is considered to have an appropriate hardness at room temperature and excellent moldability and quality retention.

[0055] In Figure 1(a), the oil component 3, surfactant 4, and water 5 are shown separately to facilitate understanding of the water-in-oil solid cosmetic composition of the present invention. However, it is believed that the oil component 3, surfactant 4, and water 5 emulsify, and in reality, emulsion particles are formed.

[0056] Next, when the water-in-oil solid cosmetic composition of the present invention is subjected to external stress, such as by applying it to the skin, as shown in Figure 1(b), the wall portion 2 of the card house structure 1 breaks and the card house structure 1 collapses, and the oil component 3, surfactant 4, and water 5 flow out from the inside surrounded by the wall portion 2 of the card house structure 1 to the outside of the card house structure 1. As a result, when the water-in-oil solid cosmetic composition of the present invention is used on the skin, a pleasant feel is imparted to the skin, and the water-in-oil solid cosmetic composition of the present invention can be easily spread on the skin.

[0057] Furthermore, after applying the water-in-oil solid cosmetic composition of the present invention to the skin, as shown in Figure 1(c), the water 5 that has leaked out of the card house structure 1 evaporates from the skin 6, providing a pleasant feel to the skin 6. The water 5 present on the surface of the skin 6 is then sealed in by the wall portion 2 and oil component 3 that constitute the card house structure 1. As a result, when moisturizing ingredients or other components are included in the water-in-oil solid cosmetic composition, these components can be retained on the surface of the skin 6.

[0058] Figure 1 is a schematic diagram illustrating the concept of the water-in-oil solid cosmetic composition of the present invention, and the present invention is not limited to this schematic diagram.

[0059] As described above, the water-in-oil solid cosmetic composition of the present invention has a pleasant feel, possesses appropriate hardness at room temperature, and has excellent quality retention, making it suitable for use in skincare cosmetics such as cleansing creams, cleansing milks, cleansing lotions, massage creams, cold creams, skin creams, skin gels, emulsions, toners, packs, serums, aftershave lotions, moisturizers, and sunscreens; body care cosmetics such as body lotions, body creams, and hand creams; and hair cosmetics such as hair lotions, hair creams, and hair styling products.

[0060] The water-in-oil solid cosmetic composition of the present invention can be used in quasi-drugs and external preparations such as ointments and disinfectants.

[0061] The water-in-oil solid cosmetic composition of the present invention can be suitably used in skincare cosmetics among the aforementioned applications. [Examples]

[0062] Next, the water-in-oil type solid cosmetic composition of the present invention will be described in more detail based on examples, but the present invention is not limited to such examples.

[0063] Examples 1-39 and Comparative Examples 1-7 Each component shown in the following tables (unit of quantity for each component listed in the table: parts by mass) was heated to 80°C and mixed under stirring to obtain a uniform composition to prepare a mixture. The obtained mixture was poured into a stick-shaped mold (inner diameter: approximately 15 mm, depth: approximately 40 mm) and cooled to room temperature to form a stick-shaped water-in-oil solid cosmetic, which was then removed from the mold. The moldability of the water-in-oil solid cosmetic was evaluated based on the following moldability evaluation method. The results are shown in each table.

[0064] [Method for evaluating moldability] The appearance of the stick-shaped water-in-oil solid cosmetic product removed from the mold was visually observed to check for any abnormalities such as deformation, chipping, or cracks, and the moldability was evaluated based on the following moldability evaluation criteria.

[0065] (Evaluation criteria for moldability) ◎: No abnormalities were observed in the appearance of the water-in-oil solid cosmetic. ○: A very slight abnormality is observed in the appearance of the water-in-oil solid cosmetic. △: An abnormality is observed in the appearance of the water-in-oil solid cosmetic, but there is no problem with its actual use. ×: The water-in-oil type solid cosmetic composition cannot be molded, or abnormalities that hinder its actual use are observed (failure).

[0066] Next, the usability, hardness, and quality retention of the stick-shaped water-in-oil solid cosmetic obtained above were investigated based on the following methods. The results are shown in the respective tables.

[0067] [Usability] A panel of women investigated the feel of a stick-type water-in-oil solid cosmetic when applied to their forearms, and evaluated its usability based on the following criteria.

[0068] (Evaluation criteria for usability) ◎: When the water-in-oil solid cosmetic was applied to the forearm, it was evaluated as having a refreshing, volatile feel and spreading smoothly on the skin's surface. ○: When the water-in-oil solid cosmetic was applied to the forearm, it was evaluated as having a slightly refreshing, volatile feel and spreading fairly smoothly on the skin's surface. △: When the water-in-oil solid cosmetic was applied to the forearm, a very slight, refreshing volatility was felt, and the spreadability on the skin surface was evaluated as slightly inferior. ×: When the water-in-oil solid cosmetic was applied to the forearm, it was evaluated as not having a refreshing, volatile feel and not spreading well on the skin surface (failure).

[0069] 〔hardness〕 Using a hardness tester (manufactured by Rheotec Co., Ltd., product name: Rheometer RT-3002D), the needle was inserted into a water-in-oil solid cosmetic at room temperature (approximately 25°C) with adapter No. 6 (diameter: 3 mm) and a needle insertion speed of 2 cm / min. The force (force at insertion) when the needle insertion distance into the water-in-oil solid cosmetic was 1 mm was measured, and the hardness was evaluated based on the following evaluation criteria.

[0070] (Hardness evaluation criteria) ◎: The force applied when inserting the needle is between 0.8N and 1.1N. ○: The force applied when inserting the needle is 0.6N or more but less than 0.8N, or greater than 1.1N and 1.8N or less. △: The force at the time of needle insertion is 0.4N or more but less than 0.6N, or greater than 1.8N but 2.5N or less. ×: The force applied during needle insertion is less than 0.4N or exceeds 2.5N (fail).

[0071] [Quality retention] A stick-shaped water-in-oil solid cosmetic was placed in a forced-air constant temperature incubator (manufactured by Yamato Scientific Co., Ltd., model number: DKN601) with the internal temperature set to 50°C and left to stand for one day. After being removed and exposed to ambient air at room temperature (approximately 25°C), the surface condition of the water-in-oil solid cosmetic was visually inspected after one hour, and its quality retention was evaluated based on the following evaluation criteria.

[0072] (Criteria for evaluating quality retention) ◎: No abnormalities were observed on the surface of the water-in-oil solid cosmetic. ○: Bleeding (seepage phenomenon) is observed on the surface of the water-in-oil solid cosmetic. △: Slight bleeding is observed on the surface of the water-in-oil solid cosmetic. ×: Significant bleeding is observed on the surface of the water-in-oil solid cosmetic (failure).

[0073] [Table 1]

[0074] [Table 2]

[0075] [Table 3]

[0076] [Table 4]

[0077] [Table 5]

[0078] The results shown in Tables 1-5 indicate that the water-in-oil solid cosmetic compositions obtained in each example exhibit excellent moldability, a pleasant feel, appropriate hardness at room temperature, and excellent quality retention even at high temperatures such as in summer. [Explanation of Symbols]

[0079] 1. Cardhouse structure 2 wall 3 Oil component 4. Surfactants 5 water 6 skin

Claims

[Claim 1] A water-in-oil solid cosmetic comprising (A) an oil component, (B) a surfactant, (C) a wax component, and (D) water, wherein the (A) oil component is an oil component containing hydrocarbon oil and ester oil, the (B) surfactant is a surfactant containing polyglyceryl polyricinoleate, and the (C) wax component is at least one wax selected from the group consisting of sunflower seed wax and candelilla wax.

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